Abstract
The treatment of damage to cartilage represents one of the most challenging clinical tasks due to the limited spontaneous healing and regenerative capability of cartilage. Clinically applied protocols for cartilage regeneration are still faced with various obstacles. The cartilage tissue engineering combines scaffolds, cells, and bioactive molecules, achieving cartilage engineering in vitro and cartilage regeneration in vivo. More recently, the controversy and difficulty in regulatory application of various cells and bioactive molecules gradually push forward the emergence of in situ inductive cartilage regeneration by recruiting endogenous regenerative cells. With these perspectives, we aim to present an overview of existing cartilage regeneration technologies with emphasis of recent progresses, development, and major steps taken toward the structure and functional regeneration of cartilage. In this chapter, essential elements of various protocols and their advantages and disadvantages and challenges and future perspectives of cartilage regeneration are discussed.
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1 Introduction
Articular cartilage is a highly developed connective tissue for weight-bearing and friction-reducing. Chondrocyte is the only type of cells in mature articular cartilage, occupying 1–10% of the tissue volume. Seventy to 80% of weight of articular cartilage is water. Collagen, proteoglycans, matrix glycoproteins, and small amount of elastin and phospholipids contribute the other 20–30% of the weight [1, 2]. Figure 9.1a shows the composition and structure of articular cartilage [3]. Cells and extracellular matrix (ECM) in cartilage distribute laterally in the superficial, randomly in the middle, and vertically in the deep layers of cartilage, respectively.
(a) Composition and structure of articular cartilage and (b) various clinical strategies for regeneration of cartilage. (Reprinted from [5] with permission)
The avascular structure in the articular cartilage determines that the chondrocytes can only get nutrients from the synovial fluid [4]. After maturation of cartilage, chondrocytes have low ability to migrate and proliferate. Hence, articular cartilage has low possibility of self-healing when lesion occurs. The intrinsic migration of bone marrow mesenchymal stem cells (BMSCs) into cartilage defect always leads to the formation of fibrocartilage [4].
Articular cartilage defects caused by arthritis and trauma severely affect the healthy life of human being. In order to treat cartilage defects, different protocols such as autologous chondrocyte implantation (ACI), mosaicplasty, microfracture, autologous matrix-induced chondrogenesis (AMIC), and cartilage tissue engineering have been developed, as shown in Fig. 9.1b [5].
ACI utilizes autologous chondrocytes grown in culture, which are reimplanted in a second-stage procedure to repair large chondral defects [6]. Mosaicplasty is indicated for the treatment of smaller defects, less than 2–4 cm2 in size, primarily on the femoral condyles. The treatment of larger lesions is limited by donor site morbidity, and the use in the patellofemoral joint is controversial [7]. To overcome these challenges, cartilage tissue engineering has been developed to realize the structural and functional regeneration of damaged cartilage [8]. As shown in Fig. 9.2a, the cells, scaffolds, and bioactive molecules are defined as three essential elements for the traditional cartilage tissue engineering [9, 10]. Various chondrogenetic cell sources are available for the cartilage tissue engineering. The chondrogenesis capability of these cells can be induced or enhanced with many biochemical or biomechanical stimulation in vitro. After culture in vitro, scaffold-based or scaffold-free engineered cartilage could be obtained and implanted for cartilage regeneration in vivo. Hence, cartilage tissue engineering involves direct intra-articular delivery of progenitor cells, progenitor cell delivery on scaffolds, or cell-free scaffolds coated with biological factors to recruit endogenous cells for articular cartilage defect repair [10]. The implantation of biomaterials or cartilage constructs is always accompanied by injury through the surgical procedures.
(a) Articular cartilage tissue engineering involving the formation of three-dimensional tissues in vitro by seeding cells into scaffolds or through scaffold-free approaches in the presence of biochemical and biomechanical stimuli. (b) Challenges in cartilage tissue engineering. (Reprinted from [10] with permission)
Inflammatory response takes a pivotal role in tissue repair and regeneration, since injury to the tissue always initiates an inflammatory response to the biomaterials. Moreover, the implantation of engineered cell–material hybrids elicits an adaptive immune reaction toward the cellular component, which in turn influences the host response to the material component [11]. When degradable biomaterials are applied, the immune response is additionally affected by the degradation products and surface changes of the biomaterials. Chronic inflammation in osteoarthritis develops as inflammatory stimuli persist at the implant site with macrophages, representing the driving force in perpetuating immune responses. Monocytes arriving at the implantation site undergo a phenotypic change to differentiate into macrophages. Their activation leads to further dissemination of chemo-attractants. Macrophages attached to the biomaterials can foster invasion of additional inflammatory cells by secreting chemokines [12]. Taking these concerns into consideration, challenges of articular cartilage tissue engineering are shown in Fig. 9.2b. In summary, difficulty in the regulation and maintenance of cell chondrogenetic phenotype, poor integration between the implanted and the host tissues, and immunoregulation of the implanted biomaterials are the main issues that impede the development of cartilage tissue engineering [10].
2 Traditional Cell-Loaded Constructs for Cartilage Regeneration
2.1 Biomaterials for Cartilage Regeneration
An ideal cartilage tissue engineering scaffold should preserve the following characteristics: biocompatible, biodegradable, highly porous, suitable for cell attachment, proliferation and differentiation, osteoconductive, noncytotoxic, flexible and elastic, and nonantigenic. Generally, biomaterials used for cartilage tissue engineering can be divided into two categories: natural polymers and synthetic polymers. Each kind of these materials has their own advantages and shortcomings [13]. The natural materials are hydrophilic and bioactive, which enhance the cell–material interactions and facilitate the cells’ chondrogenesis to the same extent. Collagen [14,15,16,17,18,19,20,21], fibrin [22,23,24,25,26,27], silk fibrin [28,29,30,31,32], hyaluronic acid (HA) [33,34,35,36,37,38,39,40,41,42,43,44,45,46], alginate [47,48,49,50,51], gelatin [40, 52,53,54,55,56,57], chitosan [58,59,60,61,62,63,64], etc. have been broadly invested in tissue engineering. The scaffolds based on these natural polymers are usually in a format of hydrogels, either with single or multicomponents. Examples of cartilage tissue engineering scaffolds based on native materials are shown in Fig. 9.3.
2.1.1 Natural Materials
Collagen, which constitutes the major part of the extracellular matrix (ECM) and is the essential component and mechanical building block of various physiological systems including cartilage, is highly recommended in cartilage tissue engineering. Collagen has many advantages including favorable biocompatibility and high density of the RGD sequences and other sequences facilitating cell adhesion and cell differentiation [19]. Macroporous scaffolds of collagen can be fabricated conveniently by freeze-drying and chemical cross-linking (Fig. 9.3a) [67]. Vickers et al. prepared a chemically cross-linked collagen type II and glycosaminoglycan (GAG) scaffold with a low cross-linking density. Culture of bone marrow stem cells in the scaffold for 4 weeks in vitro found cell-mediated contraction, increased cell number density, and a greater degree of chondrogenesis [68]. Levingstone et al. fabricated a multilayer scaffold consisting of a bone layer composed of collagen type I and hydroxyapatite, an intermediate layer composed of collagen type I and type II and hydroxyapatite, and a superficial layer composed of collagen type I and HA [69]. The scaffolds were implanted into osteochondral defects created in the medial femoral condyle of the knee joint of New Zealand white rabbits, resulting in tissue regeneration with a zonal organization, repair of the subchondral bone, formation of an overlying cartilaginous layer, and evidence of an intermediate tidemark.
Fibrin gel has several features including biocompatibility and biodegradability. The fibronectin-rich fibrin glue is an essential protein in cartilage matrix for chondrocytes-ECM interaction [26]. Fibrin gel could serve as a delivery system for chondrogenetic cells and/or bioactive molecules to facilitate cartilage regeneration (Fig. 9.3b) [65]. Fibrin gel loaded with human bone marrow-derived mesenchymal stem cells (hMSCs) and growth factor could realize full regeneration of cartilage defects in rabbits [65]. Park et al. fabricated a hybrid hydrogel composed of fibrin and HA, into which chondrocytes were implanted for culture in vivo [23]. Cartilage-like tissues were formed in the hybrid hydrogel, showing higher amounts of the ECM components, GAG, and collagen.
Hyaluronic acid (HA) is one of the most extensively studied natural materials for cartilage tissue engineering. HA is a linear polysaccharide found natively in adult articular cartilage that is involved in many cellular processes, including proliferation, morphogenesis, inflammation, and wound repair. Furthermore, HA is also important to cartilage formation and is differentially regulated during limb bud formation and mesenchymal cell condensation. HA hydrogels support chondrocyte matrix deposition and chondrogenic differentiation of mesenchymal stem cells (MSCs) [70]. HA is widely used to functionalize hydrogels or scaffolds for regeneration of cartilage defects. Sheu et al. fabricated a hydrogel based on oxidized HA and resveratrol, into which chondrocytes were implanted for culture in vitro, resulting in upregulated expression of collagen type II, aggrecan, and Sox9 genes and downregulated inflammatory factors [39].
Alginate is a natural anionic and hydrophilic polymer obtained primarily from brown seaweed and bacteria. It is composed of β-d-mannuronate and α-l-guluronate residues [71] and has been widely applied in many biomedical fields due to its excellent biocompatibility, low toxicity, and the mild gelation condition required to form a cross-linked structure [49]. Alginate can be easily modified through chemical and physical reactions to obtain derivatives and can be processed into three-dimensional scaffolds such as hydrogels, microspheres, microcapsules, sponges, foams, and fibers. Studies prove that the alginates would support the chondrogenesis [72, 73]. The cells-alginate constructs are widely used for the regeneration of articular cartilage defects, and some of the researches demonstrate quite positive results. Igarashi et al. delivered BMSCs in an ultra-purified alginate gel into articular cartilage defects in rabbit knees, resulting in complete regeneration of the defects [74].
Gelatin is a denatured collagen, but has relatively low antigenicity compared with collagen. Recently, gelatin-based biomaterials have been widely studied in tissue engineering. However, it is difficult to use pure gelatin scaffold for hard-tissue regeneration such as bone and cartilage due to its weaker mechanical strength. Hence, many studies focus on preparing pure gelatin scaffolds by using proper cross-linking methods [75] or hybrid scaffolds based on gelatin [40, 54, 55, 76]. Some natural materials such as HA, fibrin, chitosan, and synthetic materials have been extensively incorporated to obtain hybrid scaffolds, which not only preserve higher mechanical property but also retain the bioactivity of natural materials.
Chitosan is obtained by deacetylation of chitin which is an abundant natural material. The positive charge in the molecular chain may protect GAGs from hydrolysis [61]. However, the positive charge may also limit the proliferation of chondrocytes. Meanwhile, weaker mechanical property of wet chitosan also limits its application in cartilage tissue engineering [62]. Therefore, the hybrids of one or more materials are always adopted for the application of chitosan in tissue engineering.
Silk fibroin extracted from silkworm cocoons is composed of fibrous protein (fibroin), containing amino acids and glue-like protein (sericin). Silk fibroin is widely used natural material for tissue regeneration taking into consideration of their excellence in biocompatibility, degradability, and mechanical properties [77, 78]. Scaffolds based on silk fibroin for cartilage regeneration can be fabricated through a template/solution-casting method as reported (Fig. 9.3c) [29]. Biphasic scaffolds with a cartilage phase constituting of bovine cartilage matrix biofunctionalized fibroin and differentiated autologous prechondrocytes, and a bone phase (decellularized bovine bone) has been fabricated to promote cartilage regeneration in a model of joint damage in pigs [79]. Cao et al. developed a multifunctional silk-based hydrogel incorporated with metal-organic framework nanozymes, which showed enhanced cell viability as well as antioxidant and antibacterial properties. In the full-thickness osteochondral defect model of rabbit, the hydrogel displayed successful regeneration of osteochondral defect [80].
ECM materials have become more popular because the matrices retain the structure of native cartilage, which preserve mechanical and chemical signals that can induce cell differentiation and recruitment without additional biologic additives. Cartilage ECM can be obtained from either cell-derived matrices secreted during culture in vitro or from native cartilage (Fig. 9.3d) [66]. Decellularization is an effective way to fully remove all cellular components and nucleic acids or to kill the remnant cells within the matrix [79,80,81,82,83,84]. The scaffolds based on the decellularized cartilage ECM regenerate hyaline cartilage when combined with rabbit MSCs after transplantation into weight-bearing area of patellar grooves in rabbits for 12 weeks [85]. Dai et al. prepared an acellular bone matrix scaffold using iliac bone of pigs [86]. The scaffold implantation combined with microfracture was used to treat full-thickness articular defects (9 mm in diameter) without destroying the subchondral bone of pigs. 24 weeks after surgery, the defects were repaired with hyaline-like neocartilage which has the similar mechanical properties to the normal cartilage. Ayariga et al. developed a decellularized ECM scaffolds from avian articular cartilage [87]. The obtained scaffolds registered an interconnected and porous architecture, as well as stiffness comparable to the native cartilage tissues. Meanwhile, human chondrocytes survived, proliferated, and interacted with the scaffolds, showing that the decellularized scaffolds are suitable for cartilage regeneration. Das et al. prepared a cartilaginous ECM-derived biomaterial from goat ears [88]. MSCs showed obvious chondrogenic differentiation with increasing amount collagen and GAGs in the decellularized scaffolds. Upon implantation of the IGF-1-loaded cell-free scaffolds in rabbits’ osteochondral defects for 3 months, the histological and micro-CT evaluation revealed significant enhancement and regeneration of neocartilage and subchondral bone. Oh et al. prepared full-thickness porcine cartilage-derived ECM, and then fabricated mechanically reinforced ECM scaffolds by combining salt-leaching and crosslinking methods [89]. Chondrocytes showed higher levels of cartilage-specific markers in the scaffolds compared to that in the ECM scaffolds prepared by simple freeze-drying [90]. Antler decellularized cartilage-derived matrix (AdCDM) rich in collagen and GAGs was prepared by combining freezing-thawing and enzymatic degradation. Treatment of osteochondral defects with the AdCDM showed a flat and smooth surface of the neocartilage at the surgery site. Meanwhile, compared to porcine decellularized cartilage-derived matrix, AdCDM could lead to better osteochondral regeneration with higher international cartilage repair society scores (ICRS). Decellularized ECM bioinks, derived from specific native tissues or organs, have been used to fabricate 3D-printed tissues and organs. Zhang et al. developed a crosslinker-free bioink with silk fibroin and decellularized articular cartilage extracellular matrix of goat [91]. The silk fibroin and decellularized ECM interconnect with each other through physical crosslinking and entanglement, which bypass the toxicity inherent in the chemical crosslinking process of most bioinks. In vitro test proved that BMSCs highly expressed chondrogenesis-specific genes in the 3D-printed scaffold using this bioink.
2.1.2 Synthetic Materials
Synthetic polymers are also widely applied in cartilage tissue engineering, but the relatively low cell adhesive ability limits their applications. The widely used synthetic materials include poly(lactide-co-glycolide) acid (PLGA) [40, 57, 92,93,94], polycaprolactone (PCL) [95,96,97,98,99], poly(ethylene glycol) (PEG) [34, 100,101,102,103,104,105,106,107,108], etc. The scaffolds composted of solely synthetic materials can hardly realize good tissue regeneration. Therefore, the natural materials such as collagen, gelatin, fibrin, HA, and acellular ECMs, as mentioned before, can be compounded or incorporated into the synthetic polymeric scaffolds. Examples of cartilage tissue engineering scaffolds based on synthetic materials are shown in Fig. 9.4.
PCL is a semicrystalline polymer. It belongs to a family of poly α-hydroxyl esters and is one of the most widely used biodegradable polyesters for medical applications because of its biocompatibility, biodegradability, and flexibility [111]. It is widely used to prepare scaffolds for cartilage tissue engineering as well [40, 46, 47, 92, 112,113,114]. For example, Kim et al. prepared a PCL scaffold constructed with layers of electrospun and salt-leaching PCL membrane, into which chondrocytes were seeded by using an injectable heparin-based hydrogel (Fig. 9.4a). In vivo transplantation of the construct into partial-cartilage defects demonstrates significant cartilage formation with good integration to the surrounding cartilage [95]. Lebourg et al. modified PCL scaffolds with cross-linked HA to grant PCL more hydrophilic and biomimetic microenvironment. Complete regeneration of chondral defects in rabbits in vivo was confirmed by implanting the scaffolds for 24 weeks [38].
PLAG is usually synthesized via ring-opening copolymerization of lactide and glycolide, which has prominent advantages such as adjustable molecular weight and degradation rates, good mechanical properties especially toughness, and excellent processability [115]. It has been widely used to prepare scaffolds to engineer tissues including cartilage, bone, nerve, etc. [116,117,118,119,120,121]. Chang et al. seeded endothelial progenitor cells into a highly porous PLGA scaffold and implanted into the osteochondral defect in the medial femoral condyle of rabbits. After 12 weeks, the defects were regenerated with hyaline cartilage, showing a normal columnar chondrocyte arrangement, higher Sox9 expression, and greater contents of GAG and collagen type II [122]. In order to enhance the bioactivity of PLGA scaffolds, bioactive materials such as HA, gelatin, collagen, and fibrinogen can be usually incorporated. PLGA/fibrin gel-based constructs combined with MSCs and TGF-β1 chondrogenic genes could facilitate the in vivo regeneration of full-thickness cartilage defects in a rabbit model (Fig. 9.4b) [109, 123, 124]. The PLGA scaffold is fabricated by a gelatin porogen leaching method, into which fibrinogen containing cells and plasmid TGF-β1 gene complexes is infiltrated and then gelated. The chondrocytes cultured in vitro distribute evenly and maintain a round morphology in the hybrid scaffold as that in the normal cartilage [125]. The implantation of PLGA/fibrin gel/N,N,N-trimethyl chitosan chloride (TMC)/pDNA-TGF-β1 construct into osteochondral defects for 12 weeks in vivo results in regenerated cartilage with smooth surface and well integration with its surrounding tissue and subchondral bone [109].
PEG hydrogel has received wide attention due to its injectability, noncell-adhesive property, cell compatibility, and low immunogenicity. Meanwhile, PEG hydrogel could be prepared for cartilage regeneration (Fig. 9.4c) [110]. The nondegradability of PEG in physiological environment limits its application in tissue engineering, although the PEG molecules of lower molecular weight, like PEG-400, have been proved to metabolize via renal or intestine pathways [126]. Biodegradable segments such as oligo(lactic acid), oligo(ε-caprolactone), oligo(trimethylene carbonate), and phosphate groups have been introduced into the PEG-based macromers. Fan et al. developed a microcavitary hydrogel via photopolymerization of biodegradable oligo(trimethylene carbonate)-poly(ethylene glycol)-oligo(trimethylene carbonate) diacrylate macromers [106]. The cavitary structure in the hydrogel would accelerate degradation of the hydrogel. Compared with noncavitary hydrogel, the cell density and total contents of collagen and GAG are significantly higher. The hydrolytically biodegradable PEG hydrogels offer a promising platform for chondrocyte encapsulation and for tuning degradation of cartilage tissue engineering scaffolds. Skaalure et al. prepared a semi-interpenetrating network of bioactive HA and oligo(lactic acid)-PEG hydrogel, into which chondrocytes were encapsulated and cultured for 4 weeks. In this way, the contents of collagen and GAG are significantly increased [34].
2.2 Cells for Cartilage Regeneration
Chondrocytes in the cartilage produce cartilage ECMs and therefore have been the first choice for cartilage tissue engineering [127]. They are isolated from various sources such as articular cartilage, nasal septum, ribs, and ear cartilage and are extensively used for the study of cartilage regeneration in vitro and in vivo. However, one of the major limitations of chondrocytes is their instability in the culture in vitro, leading to the loss of expression of cartilage matrices such as collagen type II and aggrecan. Recently, multipotent MSCs have been gained increasing interest in cartilage tissue engineering as an alternative to autologous chondrocytes due to their ease in isolation and high expansion capacity in vitro. MSCs exhibit the potential to differentiate into chondrocytes [128], tenocytes [129], ligament cells [130], neuronal cells [131, 132], cardiomyocyte [133, 134], osteoblasts [135], and other cell types [136]. In particular, bone marrow-derived stem cells (BMSCs), adipose-derived stem cells (ADSCs), and embryonic stem cells (ESCs) are most widely applied in cartilage tissue engineering.
2.2.1 Chondrocytes
Chondrocytes are metabolically active cells that synthesize a large spectrum of ECM components such as collagen, glycoproteins, proteoglycans, and HA [127]. Since the chondrocytes are the only type of cells in articular cartilage, they are used for the regeneration of cartilage defects in priority both in vitro and in vivo [127, 137,138,139,140,141,142,143,144]. It is believed that the use of chondrocytes would lead to the formation of neotissue with exactly the same ECMs with the native cartilage [145]. The activity of chondrocytes is altered by many factors present within their chemical and mechanical environment. However, the use of chondrocytes for cartilage repair suffers from chondrocyte dedifferentiation. A proper culture and delivery of chondrocytes, including the use of chondrogenetic culture medium, growth factors, and mesenchymal stem cells, need to be well adjusted in order to keep the phenotype of chondrocytes [140]. Three-dimensional scaffolds can better mimic the native microenvironment of chondrocytes in cartilage tissue, promoting cell–cell and cell–matrix interactions and enforcing round chondrogenetic cell morphology and thereby maintaining their phenotype. Xu et al. encapsulated chondrocytes in alginate gel beads and cultured in spinner flasks in chondrogenic and chondrocyte growth medium and then subcutaneously implanted the cells-loaded beads to evaluate the ectopic chondrogenesis [142]. The results prove high deposition of glycosaminoglycan and expression of cartilage-specific genes. Lohan et al. precultured chondrocytes in polyglycolide (PGA) scaffolds for 3 weeks, which were then implanted into critical-sized osteochondral defect of rabbit knee femoropatellar groove [138, 141]. Twelve weeks after implantation, neocartilage was formed in vivo in the PGA constructs seeded with chondrocytes. The results are significantly better than those of the cell-free PGA scaffolds and empty defects.
2.2.2 Bone Marrow-Derived Stem Cells (BMSCs)
BMSCs have been extensively used for chondrogenesis in a three-dimensional culture in vitro with addition of chondrogenetic factors and regeneration of cartilage defects in animal models in vivo [33, 146,147,148,149]. BMSCs can be isolated via plastic adhesion or negative selection from bone marrow aspirate that includes a highly heterogeneous cell population such as hematopoietic cells, endothelial cells, and adipocytes [150]. However, there are some limitations of BMSCs. The relative number of BMSCs in the marrow blood is rather small, and their differentiation ability decreases significantly with age [151]. Meanwhile, the constructs of cartilage containing BMSCs can raise many problems such as fibrosis, vascularization, the “hollow” phenomenon, and shrinkage likely due to the incomplete differentiation of BMSCs, deterring the clinical translation of tissue-engineered cartilage [149]. Hence, chondrogenetic bioactive factors are always applied to promote chondrogenesis differentiation of BMSCs. Li et al. fabricated a bilayered poly(vinyl alcohol)/gelatin/vanillin (PVA/Gel/V) and nanohydroxyapatite/polyamide-6 (n-HA/PA6) scaffold, into which BMSCs were implanted. The obtained constructs were used for the regeneration of cartilage and subchondral bone defects in rabbits in vivo [152]. With BMSCs loading, the two different layers of the composite biomimetic scaffolds provide a suitable microenvironment for cells to form respective tissues.
2.2.3 Adipose-Derived Stem Cells (ADSCs)
ADSCs are becoming more and more attractive because they can be easily isolated from adipose tissues and cultured in vitro for an extended period of time with stable expansion and low levels of senescence [153]. Adipose tissue contains a large proportion of MSCs and is easily accessible in all individuals. Compared with BMSCs, the ADSCs are relatively abundant and can be easily available. In vitro and in vivo studies confirm the chondrogenetic ability of ADSCs and the ability of cartilage regeneration [154,155,156,157,158,159,160]. In the presence of platelet-rich plasma (PRP) and cartilage-specific extracellular molecules, the expression of collagen type II and aggrecan can be significantly upregulated [159, 160]. Wang et al. proved different chondrogenic degrees of ADSCs being cultured in hydrogels composed of chondroitin sulfate, HA, and heparin sulfate, respectively [157]. This chondrogenetic potential of ADSCs makes them a promising candidate for restoration of cartilage defects in vivo. Wang et al. implanted ADSCs into acellular cartilage matrices and used the cell-loading constructs to restore the articular cartilage defects of rabbits [158]. After 12 weeks of implantation, the defects are filled with neotissues, showing a smooth surface, highly expressed collagen type II and GAG, and chondrocyte-like cells in the recesses. TEM analysis confirms plenty of secretary matrix particles in the neotissue.
2.2.4 Embryonic Stem Cells (ESCs)
Recently, several studies have demonstrated the regeneration of cartilage defects in vivo by using ESC progenitor cells [161,162,163,164]. ESCs can be obtained from the blastocyst and are able to self-renew for a prolonged period of time without differentiation and, most importantly, can be differentiated into a large variety of tissues derived from all three germ layers. Although the application of ESCs would bring problems such as immunologic incompatibility, possible development of teratomas, and ethical issues in human, the in-depth study of ESCs would promote their applications in healing human diseases. For the cartilage regeneration, ESCs are also a promising choice [161, 163, 165,166,167]. Pilichi et al. demonstrated a positive result of application of nondifferentiated ESCs in vivo for osteochondral regeneration without tumorigenic and teratoma formation [164]. They treated osteochondral defects in a sheep model with ESCs for 24 weeks, proving the regeneration of articular cartilage defects with hyaline cartilage, without signs of immune rejection or teratoma. Toh et al. used TGF-β1 to induce chondrogenic differentiation of ESCs, explored the potential of these ESC-derived chondrogenic cells to produce an ECM-enriched cartilaginous tissue construct when cultured in HA hydrogel, and further investigated the cartilage regenerative ability in an osteochondral defects in a rat model [162]. Twelve weeks after implantation, a hyaline-like neocartilage layer is formed, showing good surface regularity and complete integration with the adjacent host cartilage and a regenerated subchondral bone.
2.2.5 Induced Pluripotent Stem Cells (iPSCs)
iPSCs may be generated from somatic cells through reprogramming, enabling them to possess embryonic-like properties. Shinya Yamanaka’s group initially derived the iPSCs in 2006 by reprogramming mouse fibroblasts, and human fibroblasts in the following year [168, 169]. iPSC may differentiate into other cell linages and be maintained in a nondifferentiated state for an extended period of time to cultivate cells, known as the self-renewal process. The iPSCs are similar to ESCs but less of an ethical dilemma [170]. Nam et al. obtained human iPSCs from cord blood mononuclear cells using the Sendai virus [171]. The iPSCs were differentiated into chondrogenic lineage with pellet culture and maintained for 30 days. The generated pellets showed high expression of chondrogenic gene and deposition of cartilage extracellular matrix proteins. Yamashita et al. reported that differentiation of iPSCs into hyaline cartilaginous particles and implantation of the particles into joint surface defects realized the repair of cartilage defects, and neither tumor nor ectopic tissue formation was observed [172]. Kotaka et al. labeled iPSCs magnetically with nanoscale iron particles, and delivered the cells specifically into cartilage defects in nude rats using a magnetic field [173]. The histological grading proved useful and safe for cartilage repair using the mentioned iPSCs. Liu et al. fabricated a polycaprolactone/gelatin scaffold using two separate electrospinning processes [174]. After seeded with mouse iPSCs derived from mouse dermal fibroblasts, the iPSCs-scaffolds were implanted into osteochondral defects of rabbits, resulting in an enhanced gross appearance and histological improvement, higher cartilage-specific gene expression and protein levels as well as subchondral bone regeneration.
2.2.6 Dental Pulp Stem Cells (DPSCs)
DPSCs are a type of self-renewal MSCs residing within the perivascular niche of the dental pulp [175]. DPSCs are a promising source of stem cells for tissue-engineering therapies because of their low cost and easy accessibility. DPSCs can differentiate into several different cell types, including neurons, odontoblasts, osteoblasts, adipocytes and chondrocytes [176]. Mata et al. cultured DPSCs in 3% alginate hydrogel, and implanted the hydrogel in a rabbit model of cartilage damage [177]. Three months post surgery, the cartilage defects were well regenerated. Yanasse et al. reported a successful regeneration of full-thickness articular cartilage defects in rabbits using DPSCs-loaded platelet-rich plasma scaffolds [178].
2.2.7 Umbilical Cord Mesenchymal Stem Cells (UCMSCs)
Human UCMSCs can be derived from various parts of human umbilical cord, including Wharton’s jelly, cord lining, and the perivascular region [179]. hUCMSCs are advantageous because of their high expansion capacity, noninvasive harvesting, and hypoimmunogenicity. hUCMSCs possess the same potential of chondrogenic differentiation regardless of the portion of the umbilical cord from which they are isolated [180]. According to the research of Fong et al., the chondrogenic potential of hUCMSCs is thrice that of BMSCs in producing collagen [181]. Zheng et al. fabricated polycaprolactone/hydroxyapatite (PCL-HA) scaffolds using fused deposition modeling 3D-printing technology [182]. Furthermore, rabbit UCMSCs and chondrocytes with a ratio of 3:1 were seeded on the prepared PCL/HA scaffolds. After 8 weeks of implantation into rabbits’ femoral trochlear defects, the ICRS scores of the repaired defects for the UCMSCs and chondrocyte-seeded PCL-HA scaffolds were significantly higher than the unseeded PCL/HA scaffolds. 125 patients were included in a clinical study to evaluate cartilage regeneration by implanting allogenic hUCMSCs with concomitant high tibial osteotomy (HTO) [183]. Second-look arthroscopy and ICRS grade evaluation proved the effectiveness of this treatment for patients with medial compartment osteoarthritis and various deformities. Another clinical research including 176 patients also confirmed that implantation of allogenic hUCMSCs with concomitant HTO could provide clinical outcomes in terms of pain relief, functional scores, and quality of life [184].
2.2.8 Other Cells
Besides BMSCs, ADSCs, ESCs, iPSCs, DPSCs, UCMSCs, other types of stem cells from muscle, synovium, and periosteum can also be used for the cartilage regeneration [185,186,187,188].
Several works report that synovium-derived MSCs (SMSCs) show a higher colony-forming efficiency than BMSCs. Because the SMSCs display a great potential to differentiate into chondrocytes, they are one of the best candidates for the repair of cartilage defects [189]. SMSCs have the potential for both cartilage tissue engineering in vitro and cartilage regeneration in vivo. With appropriate stimulation, SMSCs are capable of migrating into articular cartilage defects and differentiating to chondrocytes [189,190,191,192,193,194]. Fan et al. explored therapeutic chondrogenesis of rabbit SMSCs encapsulated in photopolymerized hydrogels with the treatment of TGF-β1, resulting in positive SMSC chondrogenesis. Meanwhile, SMSCs may be a type of tissue-specific stem cells, because they can respond to signaling in the joint and promote cartilage defect regeneration [195]. Pei et al. isolated SMSCs from synovial tissue of rabbit knee joints and mixed SMSCs with fibrin glue, followed by seeding into a nonwoven PGA mesh. After the constructs were prematured for 1 month in vitro, they were implanted into rabbit knees to repair osteochondral defects. Six months later, the cartilage defects were full of smooth hyaline-like cartilage with high expressions of collagen type II and GAG and were well integrated with the surrounding native cartilage. No detectable collagen type I and macrophages were found [196].
2.3 Bioactive Signals for Cartilage Regeneration
The cell growth factors are typical bioactive molecules, which can stimulate or inhibit cellular proliferation, differentiation, migration, and gene expression [198]. There are a number of essential growth factors that have regulatory effects on chondrocytes or stem cells in terms of chondrocyte maturation and cartilage formation. The candidate growth factors include transforming growth factor β (TGF-β), insulin-like growth factor-1 (IGF-1), bone morphogenic proteins (BMPs), fibroblast growth factor (FGF), platelet-derived growth factor (PDGF), etc. [199]. Each growth factor plays a different role in the migration, proliferation, and differentiation of cells as summarized in Fig. 9.5. However, it is difficult to precisely define the function of each growth factor due to the functional overlaps in temporal scale [197].
Schematic overview of the role of growth factors at different stages of chondrogenesis. (Reprinted from [197] with permission)
2.3.1 TGF-β
So far four types of TGF-β superfamily, namely, TGF-β1, TGF-β2, TGF-β3, and BMP, have been found in cartilage [198]. Activated TGF-β not only increases the synthesis of proteoglycan but also prevents degradation of cartilage ECM by inhibiting matrix metalloproteinase (MMP). These TGF-β isomers play an important role in the late stage of chondrocyte differentiation and may participate in bone formation as well. TGF-β1 induces early stage of chondrogenesis and increases the production of aggrecan and collagen type II [200]. TGF-β3 plays a role in the maturation of chondrocytes [201]. The TGF-β has been extensively used for the regeneration of cartilage defects in vitro and in vivo [122, 202,203,204,205,206,207,208,209,210,211]. For example, Yin et al. fabricated a TGF-β1-immobilized scaffold by incorporating TGF-β1-loaded gelatin microspheres into PLGA framework and evaluated the ADSC differentiation in the scaffold in vitro and regenerative ability of cartilage defect in vivo. The cell proliferation and GAG deposition in the TGF-β1-immobilized scaffold are significantly increased, and the cartilage regeneration is promoted in the defective articular cartilage in vivo [211]. Lu et al. engineered ADSCs with a baculovirus system that confers prolonged and robust TGF-β3/BMP-6 expression. Culture for 2 weeks in vitro in a porous scaffold leads to the formation of cartilaginous constructs with improved maturity and mechanical properties. After implantation into full-thickness articular cartilage defects in rabbits, these engineered constructs regenerate neocartilages that resemble native hyaline cartilage in terms of cell morphology, matrix composition, and mechanical properties. The neocartilages also have cartilage-specific zonal structures without signs of hypertrophy and degeneration and integrate well with the native cartilages [187].
2.3.2 IGFs
IGFs have a polypeptide sequence similar to proinsulin that allows cells to communicate with their physiologic environment. IGF-1 is well known to promote cell proliferation and inhibit apoptosis. IGF-1 is expressed in developing cartilage, mature cartilage, and synovial fluid of the joint. Both of in vitro and in vivo studies confirm that IGF-1 can induce chondrocyte differentiation and proliferation of MSCs and enhance proteoglycan and collagen type II synthesis [212,213,214,215,216,217,218,219]. Spiller et al. encapsulated IGF-1 in degradable PLGA microparticles and embedded the particles in PVA hydrogel. The PGA fiber scaffolds with chondrocytes were wrapped around the hydrogels and were implanted subcutaneously in athymic mice. Histology analysis proves enhanced cartilage formation in the layers surrounding the hydrogel with increased content of ECMs, mechanical properties, and integration between the cartilage layers and the hydrogels [218]. The regeneration of cartilage and subchondral bone in vivo was confirmed by injecting IGF-1 suspended HA solution to the temporomandibular in a rabbit model. Twelve and twenty-four weeks after the injection, the defects were well repaired, and nearly normal microarchitectural properties of the subchondral cancellous bone were found in the defects [217].
2.3.3 BMPs
BMPs are able to induce the formation of the cartilage and bone, which are required for the formation of prechondrogenic condensation and differentiation into chondrocytes. Meanwhile, they can increase the expression of the specific chondrocyte markers such as type X collagen [139, 205, 220,221,222,223,224,225,226,227]. BMP-2, a potent regulator of chondrogenic expression, has received considerable attention in cartilage and osteochondral tissue engineering. Jeong et al. investigated the influence of BMP-2 on the production of cartilage matrix and subsequent bone matrix by using primary chondrocytes seeded on designed three-dimensional PCL scaffolds with chemically conjugated BMP-2. The chemically conjugated BMP-2/PCL scaffolds can significantly promote better cartilage regeneration without particularly accelerating endochondral ossification both in vitro and in vivo compared with those non-BMP-2-treated scaffolds [139].
2.3.4 FGF-2
FGF-2 is known as a chondrocyte mitogen found in normal cartilage and has great potential for clinical applications. It can stimulate chondrocytes to synthesize cartilaginous matrix [228,229,230,231,232,233]. Maehara et al. impregnated a porous hydroxyapatite/collagen scaffold with FGF-2 and used the scaffolds to repair large osteochondral defects in a rabbit model. With the addition of FGF-2, the neotissue in the defects displays not only the most abundant bone regeneration but also cartilage regeneration with hyaline-like appearance [232].
2.3.5 PDGF
PDGF is a glycolytic protein released by platelets and other cells, which stimulates the growth of cells of mesenchymal origin, for example, the cartilage [234,235,236,237]. Meanwhile, the released PDGF-AA from hydrogel being filled in the full-thickness cartilage defects greatly promotes BMSC recruitment into the hydrogel. This confirms the ability of PDGF to recruit BMSCs besides promotion of cell proliferation [237].
2.3.6 Exosomes (Exos)
Exos are extracellular vesicles with 30–150 nm in diameter that are produced by cells through the paracrine pathway, which contain various types of nucleic acids and proteins [238]. Recently, Exos have been regarded as important carriers for transmitting biological signals between cells instead of waste products of cells. Exos derived from stem cells are considered as ideal substitutes for stem cells in “cell-free” cartilage regeneration [239]. Jiang et.al. combined Exos derived from human Wharton’s jelly-derived MSCs with scaffold of acellular porcine articular cartilage [240]. 6 months’ experiment in vivo proved that the Exos can promote osteochondral regeneration in a “cell-free” condition. Shao et. al. revealed that Exos derived from infrapatellar fat pad MSCs can significantly promote the proliferation as well as the expression of Sox-9, Aggrecan, and Collagen II relative genes of chondrocytes in vitro [241]. Furthermore, Shao et.al. created a rabbit articular cartilage defect with 4 mm in diameter and 1.5 mm in depth, and then treated with the Exos suspension. 12 weeks after the treatment, the defected cartilage was effectively regenerated with a hyaline morphology. In spite of these positive results using Exos to facilitate the regeneration of articular cartilage defect, the underlying mechanism of action remains unknown. Additionally, the low yield of Exos leads to a higher cost of Exos therapy than stem cell therapy, which might be the potential limitation to move the Exos therapy forward from bench to bedside [242].
2.3.7 Platelet-Rich Plasma (PRP)
PRP is a kind of autologous derivative of the whole blood, which is rich in growth factors. PRP could stimulate the migration and chondrogenic differentiation of human subchondral progenitor cells [243]. Meanwhile, PRP would counteract effects of an inflammatory environment on genes regulating matrix degradation and formation in human chondrocytes [244, 245]. Recently, PRP has commonly been utilized in the repair and regeneration of damaged articular cartilage. Lu et al. prepared an injectable hydrogel with hyaluronic acid (HA), fucoidan (FD) and gelatin (GLT), which was further cross-linked with genipin (GP) [246]. The PRP-loaded injectable hydrogel was prepared by adding PRP in the hydrogel before gelation. It could facilitate the sustained release of PRP growth factors, and promote cartilage regeneration in rabbits. Singh et al. developed a hybrid scaffold by embedding PRP/alginate-based hydrogel in porous 3D scaffold of chitosan/chondroitin sulfate/silk fibroin [247]. The hybrid construct could provide PRP-based cocktails of growth factors, which facilitates chondrogenic ECM deposition and enhanced expression of cartilage tissue-specific collagen type II and aggrecan. Autologous chondrocytes-loaded hybrid scaffolds possess the superior potential to regenerate hyaline cartilage defect of thickness around 1.10 ± 0.36 mm and integrate with surrounding tissue at the defect site.
2.4 Methods for Cartilage Tissue Engineering
2.4.1 Preculture In Vitro for Cartilage Tissue Engineering
Functional repair of focal cartilage defects requires filling the space with neotissue that has compressive properties comparable to native tissue and integration with adjacent host cartilage. One of the main issues in cartilage tissue engineering is represented by the ideal maturation of the construct before implantation in vivo, in order to optimize matrix quality and integration [248]. Considerable progress has been made toward the in vitro tissue engineering of neocartilage with compressive properties approaching native levels [249,250,251,252,253]. In 1997, Cao et al. reported a human ear-shaped tissue-engineered construct by using bovine articular chondrocytes and a nonwoven PGA scaffold [254]. Deponti et al. studied the difference of cartilage maturation with or without preculture. Articular chondrocytes were embedded in fibrin glue with preculture in vitro for 1 week and implanted subcutaneously in rat, proving better tissue maturation compared with the constructs without preculture [249]. Pei et al. mixed synovium-derived stem cells with fibrin glue, which were then seeded into nonwoven PGA mesh. After 1-month incubation with growth factors, the premature construct was used to repair osteochondral defects in a rabbit model. Six months later, the defects were full of smooth hyaline-like cartilage with high expression of collagen type II and GAG, which integrated well with the surrounding tissue too [196].
Culture of constructs in a dynamic environment involving fluid flow or agitation is beneficial for cartilage synthesis compared to the static culture conditions [255]. Therefore, various bioreactors have been applied for cartilage tissue engineering, offering advantages such as better control over culture conditions, reduced diffusional limitations for delivery of nutrients and metabolites, enhanced oxygen transfer, and exertion of mechanical and hydrodynamic forces influencing cell and tissue development [256]. Shahin et al. precultured chondrocytes in PGA scaffold for 5 weeks within a bioreactor, confirming improved GAG retention in the scaffolds [257].
2.4.2 Regeneration of Cartilage Defects In Situ
With the deep acknowledge of cell behavior regulation and bioactive molecule functions, the in situ regeneration of cartilage defects with direct implantation of cartilage tissue engineering constructs based on biomaterials, cells, and bioactive growth factors has been extensively studied. The scaffolds based on native and/or synthetic materials play a role in supporting the viability of cells and deposition of neo-ECMs, while the bioactive growth factors regulate cell differentiation and physiological activity. Numerous studies give positive regenerative results by using the bioactive constructs in repair of articular cartilage defects. As described early, cells (chondrocytes, BMSCs, ADSCs, ESCs, etc.) and bioactive growth factors (TGF-β, IGF-1, BMPs, FGF, PDGF, etc.) are loaded into scaffolds (hydrogels, porous scaffolds, etc.), which are then implanted into the cartilage defects without prematuring. Li et al. implanted a PLGA scaffold filled with fibrin gel, mesenchymal stem cells (MSCs), and poly(ethylene oxide)-b-poly(L-lysine) (PEO-b-PLL)/pDNA-TGF-β1 complexes into osteochondral defects, resulting in full in situ regeneration of the defect [123]. However, the application of constructs containing cells and bioactive molecules is still faced with obstacles like source, amount, and phenotype maintenance of MSCs during culture, immune reaction against foreign cells, as well as feasibility of clinical translation considering the ratio of performance to price [258].
Injectable hydrogels have a greater potential to promote articular cartilage regeneration considering their tailorable structural and mechanical capabilities. Importantly, the free-flowing property makes it convenient for the loading of drugs, growth factors and cells into the injectable hydrogel by simple dissolution procedures [38]. Zheng et.al. fabricated an injectable hydrogel based on silk fibroin, chitosan and thermal-sensitive glycerophosphate [259]. With the incorporation of TGF-β1 and BMSCs, the prepared injectable hydrogel could promote the regeneration of partial-thickness cartilage defect on knees of SD rats. Dong et.al. developed a physiochemical dual crosslinking injectable hydrogel using catechol-modified gelatin, dopamine-modified oxidized hyaluronic acid, and dendritic mesoporous organic silica nanoparticles with Fe3+ layers for the encapsulation of dexamethasone [260]. The obtained hydrogel was injected into osteochondral defects of 3.5 mm in diameter and 5 mm in thickness of SD rats. Post implantation for 8 weeks revealed the efficacy of the treatment on cartilage defects by the effective removal of the ROS and the inhibition of TNF-α and IL-6. Dong et.al. fabricated an injectable chitosan/silk fibroin hydrogel containing SDF-1 and PLGA microspheres loaded with Kartogenin [261]. The SDF-1 released from the hydrogel facilitated the recruitment of BMSCs in vivo, and the slowly released Kartogenin promoted the chondrogenesis of MSCs. After the hydrogel was injected into the cartilage defects (4 mm in diameter and 1.5 mm in depth) of rabbits combined with microfracture for 12 weeks, the subchondral bones and superficial cartilage were reconstructed, which were similar to the natural tissues.
3 Cell-Free Constructs for Cartilage Regeneration In Situ
Based upon the principles of tissue engineering, the stem cells and chondrocytes are usually used for cartilage regeneration. However, the controversy of using cells in tissue engineering still exists because of the uncertainty of dose, time point, as well as side effects [262]. In fact, stem cells are abundant in bone marrow and adult organs such as the brain, peripheral blood, skin, teeth, etc. Once tissues get damaged, endogenous stem/progenitor cells will migrate to the injured site through peripheral blood by responding to the immune cell-secreted biochemical signals [263, 264]. Therefore, homing of endogenous cells for tissue regeneration in situ would be a promising new therapeutic option to bypass the controversial of cell usage. Compared to that of the traditional cartilage tissue engineering, the recruitment of cells into cartilage defect to realize the regeneration in situ still remains rare [265]. Nonetheless, the cell-free scaffolds combined with anti-inflammatory molecules and BMSC-attractive chemokines would have positive influence on the regenerative outcome of cartilage defects. For example, Park et al. studied the in situ recruitment of BMSCs into cartilage defects by transplantation of polylactide/β-tricalcium phosphate (PLA/β-TCP) scaffolds containing IL-8 or MIP-3α [8]. Compared to those scaffolds without chemokines, the scaffolds with IL-8 or MIP-3α can highly facilitate the restoration of cartilage with a smoother surface and higher deposition of collagen. Wang et al. fabricated an anti-inflammatory scaffold composed of resveratrol-grafted polyacrylic acid and atelocollagen [266]. The scaffolds were transplanted into osteochondral defects without the employment of cells. After implantation for 12 weeks, the proinflammation genes such as IL-1, MMP13, and COX-2 were downregulated, while the cartilage-related genes were upregulated, leading to efficient regeneration of cartilage defects. For the sake of easier application clinically, a widely accepted biomaterial instead of a brand-new one would be the best choice for fabricating the scaffold. Dai et al. fabricated a macroporous fibrin scaffold with high Fg content and mechanical strength through a porogen leaching method by using PCL microspheres as the porogen. Together with the excellent bioactivity of Fg, the cell-free fibrin scaffold could efficiently regenerate full-thickness cartilage defects in rabbit knees, resulting in neocartilage with a smooth surface, well integrity with surrounding tissue, highly deposited GAGs and collagen type II, and higher expression of cartilage-related genes and proteins, which ensure the great potential for clinical application of Fg scaffold to achieve in situ inductive cartilage regeneration [267]. A PLGA scaffold with oriented pores in its radial direction was implanted into rabbit articular osteochondral defect for 12 weeks, confirming obvious tide mark formation, and abundant chondrocytes distributing regularly with obvious lacunas in the cartilage layer [268]. A scaffold with oriented pores in radial direction can be prepared by using methacrylated hyaluronic acid via controlled directional cooling, and followed with structure-stabilization via post photocrosslinking, and further infiltrated with PLGA to enhance the mechanical strength [269]. In vivo test proved that the composite without loading cells can facilitate simultaneous regeneration of both cartilage and subchondral bone. Meanwhile, the cell-free scaffolds can facilitate cartilage regeneration in clinic too. Roessler et al. implanted a cell-free collagen type I matrix for the treatment of large cartilage defects (mean defect size 3.71 ± 1.93 cm2, range 1.20–9.00) of the knee and conducted a short-term follow-up after the implantation. Significant pain reduction was achieved after implantation for 6 weeks, while the activity of patients was highly improved and nearly reached to preoperative value after 12 months [270].
4 Simultaneous Regeneration of Cartilage and Subchondral Bone
Articular cartilage defects can be divided into two forms, full-thickness cartilage defects without subchondral bone damage and osteochondral defects involving both the cartilage and the underlying subchondral bone [271]. Subchondral bone plays a pivotal role in supporting cartilage and will suffer from deterioration once cartilage is damaged. When damage of subchondral bone occurs, the neocartilage has poor integration with the subchondral bone, leading to negative regeneration of the articular cartilage defects [272]. Hence, the regeneration of structure and functions of the articular cartilage defects can be realized only if both cartilage and subchondral bone are simultaneously regenerated with good interface binding [273]. There are several problems that should be overcome for the regeneration of osteochondral defects, including the construction of different layers of scaffolds, well integration of the neoformed tissues with native tissues, and the effective binding of neoformed cartilage and subchondral bone [274]. Schematic design of multilayered scaffolds for osteochondral defect regeneration and typical multilayered collagen scaffolds is shown in Fig. 9.6 [69]. Osteochondral tissues encompass cartilage layer, calcified cartilage, and subchondral bone layers in the spatial scale (Fig. 9.6a). The scaffolds with a biphasic structure based on different materials and different chemical or mechanical properties are designed for the regeneration of cartilage and subchondral bone, respectively (Fig. 9.6b) [275,276,277,278,279]. The evaluation of the regenerative ability of the scaffolds in vivo has found some positive results [280,281,282,283]. For example, the biphasic PEG/hydroxyapatite scaffold with cartilage- and subchondral bone-like hierarchical nanoroughness, microstructure, and spatiotemporal bioactive cues can be prepared by the 3D-printing technology. In vitro culture proves osteochondral differentiation of BMSCs in the scaffold [284]. The bilayered scaffold composed of PLCL, PLGA, and β-tricalcium phosphate (β-TCP) has been prepared by a sintering method and a gel pressing method. The PLGA/β-TCP layer has osteoconduction activity for bone regeneration, while the elastic PLCL scaffold has mechanoactive properties for cartilage regeneration [285]. The biphasic scaffold composed of aragonite-hyaluronic acid (Ar-HA) layers shows full regenerative ability of osteochondral defects with a critical size of 6 mm in diameter and 10 mm in depth in the load-bearing femoral condyle of goats [286].
(a) Schematic design of multilayered scaffolds for osteochondral defect regeneration. (b) Three-layered collagen scaffolds. (Reprinted from [69] with permission)
Recently, 3D-printing technology has emerged as a promising strategy to fabricate scaffolds for osteochondral defects. 3D-printing provides many advantages, including well-controlled architecture (size, shape, interconnectivity, and orientation). The 3D-printed scaffold would provide structural and mechanical support, and sufficient nutrient supply, leading to regeneration of functional cartilage akin to native tissue. Depending on the biomaterials, 3D-printed scaffolds for cartilage regeneration can be classified as natural, synthetic, and inorganic scaffolds.
The natural 3D-printed scaffold is mainly designed in a form of hydrogel, by using proteins (collagen (Fig. 9.7a) [287,288,289], gelatin (Fig. 9.7b) [290,291,292,293,294,295,296,297,298,299,300,301], fibrin [292], and silk fibroin [298, 302]), polysaccharides (gellan gum [303], cellulose [303], chitosan [302], hyaluronic acid [294, 304, 305], alginate [290, 297, 303, 306,307,308,309], chondroitin sulfate [291]), and acellular matrix [295, 310, 311]. Compared with the traditional hydrogel with submicro- or nano-sized gel network, the 3D-printed hydrogel could be granted with macropores which facilitate the supply of oxygen and nutrients and the proliferation and differentiation of encapsulated cells. Li et al. fabricated a macroporous hydrogel with silk fibroin and tyramine-substituted gelatin by extrusion-based low temperature 3D printing [292]. The internal structure of the hydrogel could be well designed to improve the retention of stem cell aggregates and promote the articular cartilage repair. A bilayered hydrogel was fabricated using gellan gum, cellulose and sodium alginate [303]. Bioceramic particles were incorporated into the lower part of the hydrogel to mimic the subchondral bone. The hydrogel loaded with stem cells in the lower part, and with chondrocytes in the upper part could facilitate simultaneous regeneration of both cartilage and subchondral bone. Hydrogel with interpenetrating polymer network could be fabricated by 3D-printed technology using polyethylene glycol diacrylate, gelatin methacryloyl, and chondroitin sulfate methacrylate through photocrosslinking [291]. The designed hydrogel possessed not only adequate mechanical strength but also maintained a suitable 3D microenvironment for differentiation, proliferation and extracellular matrix production of stem cells.
3D-printed scaffolds of (a) cell-laden collagen, (b) modified PEG and gelatin, (c) modified PEG and gelatin incorporating with graphene, (d) polycaprolactone and modified gelatin, (e) short electrospinning gelatin/PLGA fibers and cartilage decellularized matrix, (f) gellan gum with Li-Mg-Si bioceramics, (g) polycaprolactone and hydroxyapatite, (h) bone layer (polycaprolactone /hydroxyapatite) and cartilage layer (chitosan/silk firoin), (i) Zn/Co-MOF-β-TCP, (j) Mo-doped bioactive glass ceramic. (Reprinted from [287, 291, 296, 299, 295, 303, 182, 302, 316, 317] with permission)
Compared with natural biomaterials, synthetic biomaterials are favored by researchers because of their strong controllability and mechanical properties. Up to now, several biodegradable synthetic polymers, including polyethylene glycol (PEG) (Fig. 9.7c) [291, 296], polyvinyl alcohol (PVA) [312], polyurethane [304, 311, 313], poly (lactic-co-glycolic acid) (PLGA) (Fig. 9.7e) [295], and polycaprolactone (PCL) (Fig. 9.7d) [182, 299, 302, 308, 309, 314, 315], have been used in 3D-printed scaffolds for cartilage regeneration. For instance, Zhou et al. developed a graphene oxide-doped, gelatin methacrylate and poly (ethylene glycol) diacrylate (PEGDA)-based 3D-printing ink, in which the PEGDA could greatly improve the printability performance of the ink [296]. Because of the strong hydrogen bonding interaction in the PEGDA solution, there exists severe extrusion swelling of the pure PEGDA solution during the most common nozzle printing process, which greatly restricts the development of 3D printing of PEGDA hydrogel. Meng et al. improved the printing accuracy of PEGDA solution by adding graphene oxide and hydroxyapatite, and realized the 3D printing of a PEGDA-based hydrogel with a biomimetic pore size gradient [312]. Inspired by the architecture of collagen fibers in native cartilage tissue, Cao et al. fabricated a tri-layered scaffold with pore size gradient based on polycaprolactone and methacrylated alginate hydrogel encapsulating stem cells [308]. The stem cells-loaded gradient 3D-printed scaffolds showed excellent cell survival, proliferation and morphology, collagen II deposition, and hopeful chondrogenic differentiation.
Moreover, the scaffolds for osteochondral repair based on bioresorbable ceramic, including hydroxyapatite (Fig. 9.7g, h) [182, 288, 297, 301, 302, 307], β-tricalcium phosphate(β-TCP) [316], and bioactive glass ceramic (Fig. 9.7f) [303, 317] can be fabricated by 3D-printing technology. Hydroxyapatite is one of the essential inorganic components from bones and teeth, which is widely applied in biomedical engineering due to their excellent biocompatibility, bioactivity, osteointegrity, and osteoconductive properties [318]. Hsieh et al. prepared a biomimetic scaffold consisting of hydroxyapatite/polycaprolactone and glycidyl-methacrylate-hyaluronic acid for healing osteochondral defects [319]. The scaffolds were implanted in the knees of a miniature pig for a period of 12 months, and realized the regeneration of hyaline cartilage. β-TCP is a typical bioresorbable ceramic for bone tissue regeneration [320]. Shu et al. prepared a 3D-printed β-TCP scaffold, which was further functionalized with zinc-cobalt bimetallic organic framework (Zn/Co-MOF) (Fig. 9.7i) [316]. The hybrid scaffolds preserve excellent antioxidative and anti-inflammatory properties to protect cells from reactive oxygen species invasion, and induce the osteogenic and chondrogenic differentiation simultaneously in vitro. Moreover, in vivo studies prove that the Zn/Co-MOF-TCP scaffolds could accelerate the integrated regeneration of cartilage and subchondral bone in severe osteochondral defects induced by osteoarthritis. Dang et al. prepared a series of molybdenum-doped bioactive glass ceramic through combining a sol-gel method with 3D-printing technology (Fig. 9.7j) [317]. The scaffold not only significantly stimulated the proliferation and differentiation of both chondrocytes and stem cells in vitro, but also showed bi-lineage bioactivities for regeneration of articular cartilage and subchondral bone tissues in vivo.
5 Histological Grading of Cartilage
Histological quality of repaired cartilage is one of the most important evaluations of success in cartilage regeneration. Up to present, various histological scoring systems are used to evaluate the quality of cartilage tissues. Basically, a scoring system should be comprehensive but also applicable to researchers with limited knowledge of cartilage histology. In summary, the systems are divided into three categories to describe the osteoarthritic, in vivo repaired, and in vitro engineered cartilage, respectively [321].
Scoring systems for osteoarthritic cartilage focus on the degenerative features of healthy or diseased cartilage. Histological-Histochemical Grading System (HHGS) is the first system for the evaluation of osteoarthritic cartilage [322]. It evaluates the cartilage structure, cell distribution, Safranin-O staining, and tidemark integrity to classify the level of cartilage damage. HHGS is applied in the grading of both human and animal cartilages [323, 324]. Although widely used, HHGS is not efficient to evaluate the specific extent of cartilage deterioration [325]. Osteoarthritis Research Society International (OARSI) developed an Osteoarthritis Cartilage Histopathology Assessment System for better evaluation of the severity and the extent of cartilage surface damage during the arthritic process [326]. The OARSI system is more adequate for the assessment of mild osteoarthritis and could be more conveniently used by less experienced observers [325].
Many scoring systems are developed to evaluate the regeneration of cartilage defect in vivo. O’Driscoll score, Pineda scale, Wakitani score, OsScore, Knutsen score, and International Cartilage Repair Society (ICRS) score are widely used [321]. O’Driscoll is the first scoring system to assess the repaired cartilage in vivo and is frequently used for cartilage analysis in animal studies [327]. However, many different subitems make it a bit lengthy and complicated to use. Pineda scale is developed to simplify the assessment and is applied to evaluate the self-healing ability of cartilage defect in rabbit at the first beginning [328]. After that, Wakitani introduced a modified scoring system based on Pineda scale, which is extensively applied to evaluate animal cartilage repair in vivo [329]. O’Driscoll, Pineda scale, and Wakitani score are mainly used to evaluate cartilage repair in animal models. In contrast to the animal studies, the study of cartilage repair in human is hard to evaluate due to the infeasible harvest of large biopsy. Considering that, Robert et al. proposed a scoring system for small biopsy of repaired human cartilage, which is named as OsScore [330]. Moreover, ICRS introduced ICRS I and ICRS II scoring systems for more easy and reliable histological evaluation of repaired cartilage [331, 332]. ICRS scoring systems are based on a catalogue of repaired cartilage as a reference for scoring. Distinguished from other systems, ICRS scoring enables discrimination of each subitem, instead of summarizing all the subitems to create a total score. Compared with the ICRS I, the ICRS II contains additional categories, making it more comprehensive. Especially when a scaffold is used in cartilage repair, a category of inflammation can be included to the ICRS II [333].
Scoring system for engineered cartilage should focus on the quality of newly generated cartilage after engineering in vitro. Few histological scoring systems are available for the evaluation of engineered cartilage. O’Driscoll introduced a simple scoring system to evaluate the density of GAGs in the engineered cartilage [334]. This system is not sufficient since many other characteristics, for example, cell morphology, are not included. Another grading system, Bern score, was validated for the evaluation of engineered cartilage [335]. In contrast to O’Driscoll score, Bern score has a broader score range, which gives more information about the characteristics of tissue [336].
6 Challenges and Perspectives
Although the cartilage tissue engineering has been investigated for over two decades, rather limited success is achieved to develop clinically relevant outcomes. Nonetheless, significant strides have been made to select optimal cell sources; to identify suitable chemistry, morphology, and compliance of scaffold materials; and to optimize culture conditions and dose and delivery of soluble factors, which are of great importance to develop models of cartilage development in vitro and regeneration of cartilage defects in vivo. Meanwhile, many efforts have been made to overcome the limitations in cell harvesting and to establish culture and implantation techniques in vitro. Novel methods of manufacture such as 3D printing have opened new horizons for constructing personalized constructs for cartilage regeneration. A thorough understanding of the biological processes at both cellular and molecular levels will ensure the safety and effectiveness of these innovations. With the deep understanding of pathological and healing principles under cartilage defects, cell homing and in situ inductive regeneration of both cartilage and subchondral bone are also full of prospects. All these developments, taken together, may in the future lead to the successful and cost-effective translation from the bench top to the bedside by using novel cell/biomaterial constructs in cartilage regeneration.
References
McDevitt CA, Marcelino J. Composition of articular cartilage. Sports Med Arthrosc Rev. 1994;2:1–12.
Poole AR, Kojima T, Yasuda T, Mwale F, Kobayashi M, Laverty S. Composition and structure of articular cartilage: a template for tissue repair. Clin Orthop Relat Res. 2001;391:S26–33.
Umlauf D, Frank S, Pap T, Bertrand J. Cartilage biology, pathology, and repair. Cell Mol Life Sci. 2010;67:4197–211.
Kay P, Freemont A, Davies D. The aetiology of multiple loose bodies. Snow storm knee. Bone Joint J. 1989;71:501–4.
Jeuken RM, Roth AK, Peters RJ, van Donkelaar CC, Thies JC, van Rhijn LW, et al. Polymers in cartilage defect repair of the knee: current status and future prospects. Polymers. 2016;8:219.
Gomoll AH, Farr J. Autologous chondrocyte implantation (ACI). Cartilage restoration. New York: Springer; 2014. p. 143–52.
Gomoll AH, Farr J, Osteochondral autograft transfer. Cartilage restoration. New York: Springer; 2014. p. 123–9.
Park MS, Kim YH, Jung Y, Kim SH, Park JC, Yoon DS, et al. In situ recruitment of human BMSCs using chemokines for articular cartilage regeneration. Cell Transplant. 2014;24(6):1067–83.
Bhardwaj N, Devi D, Mandal BB. Tissue-engineered cartilage: the crossroads of biomaterials. Cells and stimulating factors. Macromol Biosci. 2015;15:153–82.
Kwon H, Paschos NK, Hu JC, Athanasiou K. Articular cartilage tissue engineering: the role of signaling molecules. Cell Mol Life Sci. 2016;73:1173–94.
Babensee JE, Anderson JM, McIntire LV, Mikos AG. Host response to tissue engineered devices. Adv Drug Deliv Rev. 1998;33:111–39.
Badylak SF, Gilbert TW. Immune response to biologic scaffold materials. Semin Immunol. 2008;20:109–16.
Puppi D, Chiellini F, Piras AM, Chiellini E. Polymeric materials for bone and cartilage repair. Prog Polym Sci. 2010;35:403–40.
Zheng L, Fan HS, Sun J, Chen XN, Wang G, Zhang L, et al. Chondrogenic differentiation of mesenchymal stem cells induced by collagen-based hydrogel: an in vivo study. J Biomed Mater Res A. 2010;93A:783–92.
Cheng H-W, Luk KDK, Cheung KMC, Chan BP. In vitro generation of an osteochondral interface from mesenchymal stem cell-collagen microspheres. Biomaterials. 2011;32:1526–35.
Bian W, Li D, Lian Q, Li X, Zhang W, Wang K, et al. Fabrication of a bio-inspired beta-tricalcium phosphate/collagen scaffold based on ceramic stereolithography and gel casting for osteochondral tissue engineering. Rapid Prototyp J. 2012;18:68–80.
Park S-H, Song T, Bae TS, Khang G, Choi BH, Park SR, et al. Comparative analysis of collagens extracted from different animal sources for application of cartilage tissue engineering. Int J Precis Eng Manuf. 2012;13:2059–66.
Zhang Q, Lu H, Kawazoe N, Chen G. Preparation of collagen scaffolds with controlled pore structures and improved mechanical property for cartilage tissue engineering. J Bioact Compat Polym. 2013;28:426–38.
Zheng L, Lu HQ, Fan HS, Zhang XD. Reinforcement and chemical cross-linking in collagen-based scaffolds in cartilage tissue engineering: a comparative study. Iran Polym J. 2013;22:833–42.
Yuan T, Zhang L, Li K, Fan H, Fan Y, Liang J, et al. Collagen hydrogel as an immunomodulatory scaffold in cartilage tissue engineering. J Biomed Mater Res B Appl Biomater. 2014;102:337–44.
Zheng L, Jiang X, Chen X, Fan H, Zhang X. Evaluation of novel in situ synthesized nano-hydroxyapatite/collagen/alginate hydrogels for osteochondral tissue engineering. Biomed Mater. 2014;9(6):065004.
Silverman RP, Passaretti D, Huang W, Randolph MA, Yaremchuk M. Injectable tissue-engineered cartilage using a fibrin glue polymer. Plast Reconstr Surg. 1999;103:1809–18.
Park SH, Park SR, Chung SI, Pai KS, Min BH. Tissue-engineered cartilage using fibrin/hyaluronan composite gel and its in vivo implantation. Artif Organs. 2005;29:838–45.
Ahmed TAE, Giulivi A, Griffith M, Hincke M. Fibrin glues in combination with mesenchymal stem cells to develop a tissue-engineered cartilage substitute. Tissue Eng Part A. 2011;17:323–35.
Singh K, Moyer H, Williams JK, Schwartz Z, Boyan BD. Fibrin glue a scaffold for cellular-based therapy in a critical-sized defect. Ann Plast Surg. 2011;66:301–5.
Hong HJ, Lee JS, Choi JW, Min BH, Lee HB, Kim CH. Transplantation of autologous chondrocytes seeded on a fibrin/hyaluronan composite gel into tracheal cartilage defects in rabbits: preliminary results. Artif Organs. 2012;36:998–1006.
Cakmak O, Babakurban ST, Akkuzu HG, Bilgi S, Ovali E, Kongur M, et al. Injectable tissue-engineered cartilage using commercially available fibrin glue. Laryngoscope. 2013;123:2986–92.
Bhardwaj N, Kundu SC. Chondrogenic differentiation of rat MSCs on porous scaffolds of silk fibroin/chitosan blends. Biomaterials. 2012;33:2848–57.
Chen C-H, Liu JM-J, Chua C-K, Chou S-M, Shyu VB-H, Chen J-P. Cartilage tissue engineering with silk fibroin scaffolds fabricated by indirect additive manufacturing technology. Materials. 2014;7:2104–19.
Han K-S, Song JE, Tripathy N, Kim H, Moon BM, Park CH, et al. Effect of pore sizes of silk scaffolds for cartilage tissue engineering. Macromol Res. 2015;23:1091–7.
Yan L-P, Silva-Correia J, Oliveira MB, Vilela C, Pereira H, Sousa RA, et al. Bilayered silk/silk-nanoCaP scaffolds for osteochondral tissue engineering: in vitro and in vivo assessment of biological performance. Acta Biomater. 2015;12:227–41.
Yodmuang S, McNamara SL, Nover AB, Mandal BB, Aganwal M, Kelly T-AN, et al. Silk microfiber-reinforced silk hydrogel composites for functional cartilage tissue repair. Acta Biomater. 2015;11:27–36.
Snyder TN, Madhavan K, Intrator M, Dregalla RC, Park D. A fibrin/hyaluronic acid hydrogel for the delivery of mesenchymal stem cells and potential for articular cartilage repair. J Biol Eng. 2014;8:10.
Skaalure SC, Dimson SO, Pennington AM, Bryant SJ. Semi-interpenetrating networks of hyaluronic acid in degradable PEG hydrogels for cartilage tissue engineering. Acta Biomater. 2014;10:3409–20.
Mintz BR, Cooper JA. Hybrid hyaluronic acid hydrogel/poly(epsilon-caprolactone) scaffold provides mechanically favorable platform for cartilage tissue engineering studies. J Biomed Mater Res A. 2014;102:2918–26.
Magalhaes J, Crawford A, Hatton PV, Blanco FJ, Roman JS. Poly(2-ethyl-(2-pyrrolidone) methacrylate) and hyaluronic acid-based hydrogels for the engineering of a cartilage-like tissue using bovine articular chondrocytes. J Bioact Compat Polym. 2014;29:545–59.
Levett PA, Hutmacher DW, Malda J, Klein TJ. Hyaluronic acid enhances the mechanical properties of tissue-engineered cartilage constructs. PloS One. 2014;9:e113216.
Lebourg M, Martinez-Diaz S, Garcia-Giralt N, Torres-Claramunt R, Ribelles JLG, Vila-Canet G, et al. Cell-free cartilage engineering approach using hyaluronic acid-polycaprolactone scaffolds: a study in vivo. J Biomater Appl. 2014;28:1304–15.
Sheu SY, Chen WS, Sun JS, Lin FH, Wu T. Biological characterization of oxidized hyaluronic acid/resveratrol hydrogel for cartilage tissue engineering. J Biomed Mater Res A. 2013;101:3457–66.
Chang NJ, Jhung YR, Yao CK, Yeh ML. Hydrophilic gelatin and hyaluronic acid-treated PLGA scaffolds for cartilage tissue engineering. J Appl Biomater Funct Mater. 2013;11:45–52.
Toh WS, Lim TC, Kurisawa M, Spector M. Modulation of mesenchymal stem cell chondrogenesis in a tunable hyaluronic acid hydrogel microenvironment. Biomaterials. 2012;33:3835–45.
Matsiko A, Levingstone TJ, O’Brien FJ, Gleeson JP. Addition of hyaluronic acid improves cellular infiltration and promotes early-stage chondrogenesis in a collagen-based scaffold for cartilage tissue engineering. J Mech Behav Biomed Mater. 2012;11:41–52.
Erickson IE, Kestle SR, Zellars KH, Farrell MJ, Kim M, Burdick JA, et al. High mesenchymal stem cell seeding densities in hyaluronic acid hydrogels produce engineered cartilage with native tissue properties. Acta Biomater. 2012;8:3027–34.
Tan HP, Chu CR, Payne KA, Marra KG. Injectable in situ forming biodegradable chitosan-hyaluronic acid based hydrogels for cartilage tissue engineering. Biomaterials. 2009;30:2499–506.
Park SJ, Yu SM, Chun MH, Chun HJ, Kim CH. Effect of hyaluronic acid on attachment and proliferation of chondrocyte on chitosan/hyaluronic acid bead scaffolds. Tissue Eng Regen Med. 2009;6:438–44.
Jung SH, Jang JW, Kim SH, Hong HH, Oh AY, Rhee JM, et al. Articular cartilage regeneration using hyaluronic acid loaded PLGA scaffold by emulsion freeze-drying method. Tissue Eng Regen Med. 2008;5:643–9.
Choi SW, Moon SK, Chu JY, Lee HW, Park TJ, Kim JH. Alginate hydrogel embedding poly(D, L-lactide-co-glycolide) porous scaffold disks for cartilage tissue engineering. Macromol Res. 2012;20:447–52.
Kim HM, Park JY, Kim EY, Song JE, Kwon SY, Chung JW, et al. Tissue engineered cartilage reconstruction with alginate sponge containing demineralized bone particles. Polym Korea. 2014;38:278–85.
Park H, Lee KY. Cartilage regeneration using biodegradable oxidized alginate/hyaluronate hydrogels. J Biomed Mater Res A. 2014;102:4519–25.
Fan CJ, Wang DA. Potential use of alginate beads as a chondrocyte delivery vehicle and stepwise dissolving porogen in a hydrogel scaffold for cartilage tissue engineering. RSC Adv. 2015;5:80688–97.
Reppel L, Schiavi J, Charif N, Leger L, Yu H, Pinzano A, et al. Chondrogenic induction of mesenchymal stromal/stem cells from Wharton’s jelly embedded in alginate hydrogel and without added growth factor: an alternative stem cell source for cartilage tissue engineering. Stem Cell Res Ther. 2015;6:260.
Xue JX, Feng B, Zheng R, Lu Y, Zhou GD, Liu W, et al. Engineering ear-shaped cartilage using electrospun fibrous membranes of gelatin/polycaprolactone. Biomaterials. 2013;34:2624–31.
Levett PA, Melchels FPW, Schrobback K, Hutmacher DW, Malda J, Klein TJ. A biomimetic extracellular matrix for cartilage tissue engineering centered on photocurable gelatin, hyaluronic acid and chondroitin sulfate. Acta Biomater. 2014;10:214–23.
Zheng R, Duan HC, Xue JX, Liu Y, Feng B, Zhao SF, et al. The influence of gelatin/PCL ratio and 3-D construct shape of electrospun membranes on cartilage regeneration. Biomaterials. 2014;35:152–64.
Kuo CY, Chen CH, Hsiao CY, Chen JP. Incorporation of chitosan in biomimetic gelatin/chondroitin-6-sulfate/hyaluronan cryogel for cartilage tissue engineering. Carbohydr Polym. 2015;117:722–30.
Miao T, Miller EJ, McKenzie C, Oldinski RA. Physically crosslinked polyvinyl alcohol and gelatin interpenetrating polymer network theta-gels for cartilage regeneration. J Mater Chem B. 2015;3:9242–9.
Yin F, Cai JF, Zen W, Wei YH, Zhou W, Yuan F, et al. Cartilage regeneration of adipose-derived stem cells in the TGF-beta 1-immobilized PLGA-gelatin scaffold. Stem Cell Rev Rep. 2015;11:453–9.
Breyner NM, Hell RCR, Carvalho LRP, Machado CB, Peixoto Filho IN, Valerio P, et al. Effect of a three-dimensional chitosan porous scaffold on the differentiation of mesenchymal stem cells into chondrocytes. Cells Tissues Organs. 2010;191:119–28.
Ragetly GR, Slavik GJ, Cunningham BT, Schaeffer DJ, Griffon DJ. Cartilage tissue engineering on fibrous chitosan scaffolds produced by a replica molding technique. J Biomed Mater Res A. 2010;93A:46–55.
Bi L, Cao Z, Hu Y, Song Y, Yu L, Yang B, et al. Effects of different cross-linking conditions on the properties of genipin-cross-linked chitosan/collagen scaffolds for cartilage tissue engineering. J Mater Sci Mater Med. 2011;22:51–62.
Oliveira JT, Crawford A, Mundy JL, Sol PC, Correlo VM, Bhattacharya M, et al. Novel melt-processable chitosan-polybutylene succinate fibre scaffolds for cartilage tissue engineering. J Biomater Sci Polym Ed. 2011;22:773–88.
Whu SW, Hung K-C, Hsieh K-H, Chen C-H, Tsai C-L, S-h H. In vitro and in vivo evaluation of chitosan-gelatin scaffolds for cartilage tissue engineering. Mater Sci Eng C Mater Biol Appl. 2013;33:2855–63.
Garcia-Lopez J, Garciadiego-Cazares D, Melgarejo-Ramirez Y, Sanchez-Sanchez R, Solis-Arrieta L, Garcia-Carvajal Z, et al. Chondrocyte differentiation for auricular cartilage reconstruction using a chitosan based hydrogel. Histol Histopathol. 2015;30:1477–85.
Muzzarelli RAA, El Mehtedi M, Bottegoni C, Aquili A, Gigante A. Genipin-crosslinked chitosan gels and scaffolds for tissue engineering and regeneration of cartilage and bone. Mar Drugs. 2015;13:7314–38.
Park JS, Yang HN, Woo DG, Jeon SY, Park K-H. Chondrogenesis of human mesenchymal stem cells in fibrin constructs evaluated in vitro and in nude mouse and rabbit defects models. Biomaterials. 2011;32:1495–507.
Wu J, Ding Q, Dutta A, Wang Y, Huang Y-h, Weng H, et al. An injectable extracellular matrix derived hydrogel for meniscus repair and regeneration. Acta Biomater. 2015;16:49–59.
Zhang Q, Lu H, Kawazoe N, Chen G. Pore size effect of collagen scaffolds on cartilage regeneration. Acta Biomater. 2014;10:2005–13.
Vickers SM, Gotterbarm T, Spector M. Cross-linking affects cellular condensation and chondrogenesis in Type II collagen-GAG scaffolds seeded with bone marrow-derived mesenchymal stem cells. J Orthop Res. 2010;28:1184–92.
Levingstone TJ, Thompson E, Matsiko A, Schepens A, Gleeson JP, O’Brien FJ. Multi-layered collagen-based scaffolds for osteochondral defect repair in rabbits. Acta Biomater. 2016;32:149–60.
Kim IL, Mauck RL, Burdick JA. Hydrogel design for cartilage tissue engineering: a case study with hyaluronic acid. Biomaterials. 2011;32:8771–82.
Sun JC, Tan HP. Alginate-based biomaterials for regenerative medicine applications. Materials. 2013;6:1285–309.
Steinert A, Weber M, Dimmler A, Julius C, Schütze N, Nöth U, et al. Chondrogenic differentiation of mesenchymal progenitor cells encapsulated in ultrahigh – viscosity alginate. J Orthop Res. 2003;21:1090–7.
Paige KT, Cima LG, Yaremchuk MJ, Schloo BL, Vacanti JP, Vacanti CA. De novo cartilage generation using calcium alginate-chondrocyte constructs. Plast Reconstr Surg. 1996;97:168–78. discussion 79–80.
Igarashi T, Iwasaki N, Kasahara Y, Minami A. A cellular implantation system using an injectable ultra-purified alginate gel for repair of osteochondral defects in a rabbit model. J Biomed Mater Res A. 2010;94A:844–55.
Lien SM, Li WT, Huang TJ. Genipin-crosslinked gelatin scaffolds for articular cartilage tissue engineering with a novel crosslinking method. Mater Sci Eng C Biomim Supramol Syst. 2008;28:36–43.
Kim DH, Heo SJ, Shin JW, Mun CW, Park KM, Park KD, et al. Preparation of thermosensitive gelatin-pluronic copolymer for cartilage tissue engineering. Macromol Res. 2010;18:387–91.
Shin EY, Park JH, Shin ME, Song JE, Carlomagno C, Khang G. Evaluation of chondrogenic differentiation ability of bone marrow mesenchymal stem cells in silk fibroin/gellan gum hydrogels using miR-30. Macromol Res. 2019;27(4):369–76.
Farokhi M, Mottaghitalab F, Fatahi Y, et al. Silk fibroin scaffolds for common cartilage injuries: possibilities for future clinical applications. Eur Polym J. 2019;115:251–67.
Perez-Silos V, Moncada-Saucedo NK, Pena-Martinez V, et al. A cellularized biphasic implant based on a bioactive silk fibroin promotes integration and tissue organization during osteochondral defect repair in a porcine model. Int J Mol Sci. 2019;20(20):5145.
Cao Z, Wang H, Chen J, et al. Silk-based hydrogel incorporated with metal-organic framework nanozymes for enhanced osteochondral regeneration. Bioact Mater. 2023;20:221–42.
Sutherland AJ, Beck EC, Dennis SC, Converse GL, Hopkins RA, Berkland CJ, et al. Decellularized cartilage may be a chondroinductive material for osteochondral tissue engineering. PloS One. 2015;10:e0121966.
Fermor HL, Russell SL, Williams S, Fisher J, Ingham E. Development and characterisation of a decellularised bovine osteochondral biomaterial for cartilage repair. J Mater Sci Mater Med. 2015;26:186.
Chen Y-C, Chen R-N, Jhan H-J, Liu D-Z, Ho H-O, Mao Y, et al. Development and characterization of acellular extracellular matrix scaffolds from porcine menisci for use in cartilage tissue engineering. Tissue Eng Part C Methods. 2015;21:971–86.
Benders KEM, van Weeren PR, Badylak SF, Saris DBF, Dhert WJA, Malda J. Extracellular matrix scaffolds for cartilage and bone regeneration. Trends Biotechnol. 2013;31:169–76.
Yang Z, Shi Y, Wei X, He J, Yang S, Dickson G, et al. Fabrication and repair of cartilage defects with a novel acellular cartilage matrix scaffold. Tissue Eng Part C Methods. 2009;16:865–76.
Dai L, He Z, Jiang Y, et al. One-step strategy for cartilage repair using acellular bone matrix scaffold based in situ tissue engineering technique in a preclinical minipig model. Am J Transl Res. 2019;11(10):6650–9.
Ayariga JA, Huang H, Dean D. Decellularized avian cartilage, a promising alternative for human cartilage tissue regeneration. Materials. 2022;15(5):1974.
Das P, Mishra R, Devi B, et al. Decellularized xenogenic cartilage extracellular matrix (ECM) scaffolds for the reconstruction of osteochondral defects in rabbits. J Mater Chem B. 2021;9(24):4873–94.
Oh HJ, Kim SH, Cho J-H, Park S-H, Min B-H. Mechanically reinforced extracellular matrix scaffold for application of cartilage tissue engineering. Tissue Eng Regener Med. 2018;15(3):287–99.
Chu W, Hu G, Peng L, Zhang W, Ma Z. The use of a novel deer antler decellularized cartilage-derived matrix scaffold for repair of osteochondral defects. J Biol Eng. 2021;15(1):23.
Zhang X, Liu Y, Luo C, et al. Crosslinker-free silk/decellularized extracellular matrix porous bioink for 3D bioprinting-based cartilage tissue engineering. Mater Sci Eng C. 2021;118:111388.
Fan HB, Hu YY, Zhang CL, Li XS, Lv R, Qin L, et al. Cartilage regeneration using mesenchymal stem cells and a PLGA-gelatin/chondroitin/hyaluronate hybrid scaffold. Biomaterials. 2006;27:4573–80.
He X, Lu H, Kawazoe N, Tateishi T, Chen G. A novel cylinder-type poly(L-lactic acid)-collagen hybrid sponge for cartilage tissue engineering. Tissue Eng Part C Methods. 2010;16:329–38.
Andreas K, Zehbe R, Kazubek M, Grzeschik K, Sternberg N, Baumler H, et al. Biodegradable insulin-loaded PLGA microspheres fabricated by three different emulsification techniques: investigation for cartilage tissue engineering. Acta Biomater. 2011;7:1485–95.
Kim M, Hong B, Lee J, Kim SE, Kang SS, Kim YH, et al. Composite system of PLCL scaffold and heparin-based hydrogel for regeneration of partial-thickness cartilage defects. Biomacromolecules. 2012;13:2287–98.
Perez Olmedilla M, Lebourg M, Escobar Ivirico JL, Nebot I, Garcia Giralt N, Gallego Ferrer G, et al. In vitro 3D culture of human chondrocytes using modified epsilon-caprolactone scaffolds with varying hydrophilicity and porosity. J Biomater Appl. 2012;27:299–309.
Cai Y, Li J, Poh CK, Tan HC, Thian ES, Fuh JYH, et al. Collagen grafted 3D polycaprolactone scaffolds for enhanced cartilage regeneration. J Mater Chem B. 2013;1:5971–6.
Chen C-H, Shyu VB-H, Chen J-P, Lee M-Y. Selective laser sintered poly-epsilon-caprolactone scaffold hybridized with collagen hydrogel for cartilage tissue engineering. Biofabrication. 2014;6:015004.
Kundu J, Shim J-H, Jang J, Kim S-W, Cho D-W. An additive manufacturing-based PCL-alginate-chondrocyte bioprinted scaffold for cartilage tissue engineering. J Tissue Eng Regen Med. 2015;9:1286–97.
Hwang YS, Sangaj N, Varghese S. Interconnected macroporous poly(ethylene glycol) cryogels as a cell scaffold for cartilage tissue engineering. Tissue Eng Part A. 2010;16:3033–41.
Zhang C, Sangaj N, Hwang YS, Phadke A, Chang CW, Varghese S. Oligo(trimethylene carbonate)-poly(ethylene glycol)-oligo(trimethylene carbonate) triblock-based hydrogels for cartilage tissue engineering. Acta Biomater. 2011;7:3362–9.
Rennerfeldt DA, Renth AN, Talata Z, Gehrke SH, Detamore MS. Tuning mechanical performance of poly(ethylene glycol) and agarose interpenetrating network hydrogels for cartilage tissue engineering. Biomaterials. 2013;34:8241–57.
Roberts JJ, Bryant SJ. Comparison of photopolymerizable thiol-ene PEG and acrylate-based PEG hydrogels for cartilage development. Biomaterials. 2013;34:9969–79.
Yu F, Cao XD, Li YL, Zeng L, Yuan B, Chen XF. An injectable hyaluronic acid/PEG hydrogel for cartilage tissue engineering formed by integrating enzymatic crosslinking and Diels-Alder “click chemistry”. Polym Chem. 2014;5:1082–90.
Yu F, Cao XD, Li YL, Zeng L, Zhu JH, Wang G, et al. Diets-Alder crosslinked HA/PEG hydrogels with high elasticity and fatigue resistance for cell encapsulation and articular cartilage tissue repair. Polym Chem. 2014;5:5116–23.
Fan CJ, Wang DA. A biodegradable PEG-based micro-cavitary hydrogel as scaffold for cartilage tissue engineering. Eur Polym J. 2015;72:651–60.
Skaalure SC, Chu S, Bryant SJ. An enzyme-sensitive PEG hydrogel based on aggrecan catabolism for cartilage tissue engineering. Adv Healthc Mater. 2015;4:420–31.
Sridhar BV, Brock JL, Silver JS, Leight JL, Randolph MA, Anseth KS. Development of a cellularly degradable PEG hydrogel to promote articular cartilage extracellular matrix deposition. Adv Healthc Mater. 2015;4:702–13.
Wang W, Li B, Li Y, Jiang Y, Ouyang H, Gao C. In vivo restoration of full-thickness cartilage defects by poly (lactide-co-glycolide) sponges filled with fibrin gel, bone marrow mesenchymal stem cells and DNA complexes. Biomaterials. 2010;31:5953–65.
Sharifi S, Blanquer SBG, van Kooten TG, Grijpma DW. Biodegradable nanocomposite hydrogel structures with enhanced mechanical properties prepared by photo-crosslinking solutions of poly(trimethylene carbonate)–poly(ethylene glycol)–poly(trimethylene carbonate) macromonomers and nanoclay particles. Acta Biomater. 2012;8:4233–43.
Kim H-J, Lee J-H, Im G-I. Chondrogenesis using mesenchymal stem cells and PCL scaffolds. J Biomed Mater Res A. 2010;92A:659–66.
Munirah S, Kim SH, Ruszymah BHI, Khang G. The use of fibrin and poly(lactic-co-glycolic acid) hybrid scaffold for articular cartilage tissue engineering: an in vivo analysis. Eur Cell Mater. 2008;15:41–51.
Quinlan E, Lopez-Noriega A, Thompson E, Kelly HM, Cryan SA, O’Brien FJ. Development of collagen-hydroxyapatite scaffolds incorporating PLGA and alginate microparticles for the controlled delivery of rhBMP-2 for bone tissue engineering. J Control Release. 2015;198:71–9.
Sato T, Chen GP, Ushida T, Ishii T, Ochiai N, Tateishi T. Tissue-engineered cartilage by in vivo culturing of chondrocytes in PLGA-collagen hybrid sponge. Mater Sci Eng C Biomim Supramol Syst. 2001;17:83–9.
Pan Z, Ding J. Poly(lactide-co-glycolide) porous scaffolds for tissue engineering and regenerative medicine. Interface Focus. 2012;2:366–77.
Chang N-J, Lin C-C, Shie M-Y, Yeh M-L, Li C-F, Liang P-I, et al. Positive effects of cell-free porous PLGA implants and early loading exercise on hyaline cartilage regeneration in rabbits. Acta Biomater. 2015;28:128–37.
Jose MV, Thomas V, Johnson KT, Dean DR, Nyalro E. Aligned PLGA/HA nanofibrous nanocomposite scaffolds for bone tissue engineering. Acta Biomater. 2009;5:305–15.
Kim SS, Park MS, Jeon O, Choi CY, Kim BS. Poly(lactide-co-glycolide)/hydroxyapatite composite scaffolds for bone tissue engineering. Biomaterials. 2006;27:1399–409.
Lee JY, Bashur CA, Goldstein AS, Schmidt CE. Polypyrrole-coated electrospun PLGA nanofibers for neural tissue applications. Biomaterials. 2009;30:4325–35.
Oh SH, Kim JH, Song KS, Jeon BH, Yoon JH, Seo TB, et al. Peripheral nerve regeneration within an asymmetrically porous PLGA/Pluronic F127 nerve guide conduit. Biomaterials. 2008;29:1601–9.
Uematsu K, Hattori K, Ishimoto Y, Yamauchi J, Habata T, Takakura Y, et al. Cartilage regeneration using mesenchymal stem cells and a three-dimensional poly-lactic-glycolic acid (PLGA) scaffold. Biomaterials. 2005;26:4273–9.
Chang NJ, Lam CF, Lin CC, Chen WL, Li CF, Lin YT, et al. Transplantation of autologous endothelial progenitor cells in porous PLGA scaffolds create a microenvironment for the regeneration of hyaline cartilage in rabbits. Osteoarthr Cartil. 2013;21:1613–22.
Li B, Yang J, Ma L, Li F, Tu Z, Gao C. Fabrication of poly(lactide-co-glycolide) scaffold filled with fibrin gel, mesenchymal stem cells, and poly(ethylene oxide)-b-poly(L-lysine)/TGF-beta 1 plasmid DNA complexes for cartilage restoration in vivo. J Biomed Mater Res A. 2013;101:3097–108.
Wang W, Li B, Yang J, Xin L, Li Y, Yin H, et al. The restoration of full-thickness cartilage defects with BMSCs and TGF-beta 1 loaded PLGA/fibrin gel constructs. Biomaterials. 2010;31:8964–73.
Wang W, Li D, Wang M-c, Li Y-l. A hybrid scaffold of poly (lactide-co-glycolide) sponge filled with fibrin gel for cartilage tissue engineering. Chin J Polym Sci. 2011;29:233–40.
Robinson GM, Orrego H, Israel Y, Devenyi P, Kapur BM. Low-molecular-weight polyethylene-glycol as a probe of gastrointestinal permeability after alcohol ingestion. Dig Dis Sci. 1981;26:971–7.
Akkiraju H, Nohe A. Role of chondrocytes in cartilage formation, progression of osteoarthritis and cartilage regeneration. J Dev Biol. 2015;3:177–92.
Mackay AM, Beck SC, Murphy JM, Barry FP, Chichester CO, Pittenger MF. Chondrogenic differentiation of cultured human mesenchymal stem cells from marrow. Tissue Eng. 1998;4:415–28.
Wang Q-W, Chen Z-L, Piao Y-J. Mesenchymal stem cells differentiate into tenocytes by bone morphogenetic protein (BMP) 12 gene transfer. J Biosci Bioeng. 2005;100:418–22.
Lee IC, Wang J-H, Lee Y-T, Young T-H. The differentiation of mesenchymal stem cells by mechanical stress or/and co-culture system. Biochem Biophys Res Commun. 2007;352:147–52.
Dezawa M, Kanno H, Hoshino M, Cho H, Matsumoto N, Itokazu Y, et al. Specific induction of neuronal cells from bone marrow stromal cells and application for autologous transplantation. J Clin Invest. 2004;113:1701–10.
Tropel P, Platet N, Platel J-C, Noel D, Albrieux M, Benabid A-L, et al. Functional neuronal differentiation of bone marrow-derived mesenchymal stem cells. Stem Cells. 2006;24:2868–76.
Li HW, Yu B, Zhang Y, Pan ZW, Wei XA, Li HL. Jagged1 protein enhances the differentiation of mesenchymal stem cells into cardiomyocytes. Biochem Biophys Res Commun. 2006;341:320–5.
Li L, Zhu J, Tian J, Liu X, Feng C. A role for Gcn5 in cardiomyocyte differentiation of rat mesenchymal stem cells. Mol Cell Biochem. 2010;345:309–16.
Jaiswal N, Haynesworth SE, Caplan AI, Bruder SP. Osteogenic differentiation of purified, culture-expanded human mesenchymal stem cells in vitro. J Cell Biochem. 1997;64:295–312.
Chamberlain G, Fox J, Ashton B, Middleton J. Concise review: mesenchymal stem cells: their phenotype, differentiation capacity, immunological features, and potential for homing. Stem Cells. 2007;25:2739–49.
Kim M, Kim SE, Kang SS, Kim YH, Tae G. The use of de-differentiated chondrocytes delivered by a heparin-based hydrogel to regenerate cartilage in partial-thickness defects. Biomaterials. 2011;32:7883–96.
Lohan A, Marzahn U, El Sayed K, Haisch A, Kohl B, Mueller RD, et al. In vitro and in vivo neo-cartilage formation by heterotopic chondrocytes seeded on PGA scaffolds. Histochem Cell Biol. 2011;136:57–69.
Jeong CG, Zhang H, Hollister SJ. Three-dimensional polycaprolactone scaffold-conjugated bone morphogenetic protein-2 promotes cartilage regeneration from primary chondrocytes in vitro and in vivo without accelerated endochondral ossification. J Biomed Mater Res A. 2012;100A:2088–96.
Hubka KM, Dahlin RL, Meretoja VV, Kasper FK, Mikos AG. Enhancing chondrogenic phenotype for cartilage tissue engineering: monoculture and coculture of articular chondrocytes and mesenchymal stem cells. Tissue Eng Part B Rev. 2014;20:641–54.
Lohan A, Marzahn U, El Sayed K, Haisch A, Mueller RD, Kohl B, et al. Osteochondral articular defect repair using auricle-derived autologous chondrocytes in a rabbit model. Ann Anat. 2014;196:317–26.
Xu F, Xu L, Wang Q, Ye Z, Zhou Y, Tan W-S. 3D dynamic culture of rabbit articular chondrocytes encapsulated in alginate gel beads using spinner flasks for cartilage tissue regeneration. Biomed Res Int. 2014;2014:539789.
Li G, Fu N, Xie J, Fu Y, Deng S, Cun X, et al. Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) based electrospun 3D scaffolds for delivery of autogeneic chondrocytes and adipose-derived stem cells: evaluation of cartilage defects in rabbit. J Biomed Nanotechnol. 2015;11:105–16.
Omobono MA, Zhao X, Furlong MA, Kwon C-H, Gill TJ, Randolph MA, et al. Enhancing the stiffness of collagen hydrogels for delivery of encapsulated chondrocytes to articular lesions for cartilage regeneration. J Biomed Mater Res A. 2015;103:1332–8.
Bryant SJ, Bender RJ, Durand KL, Anseth KS. Encapsulating chondrocytes in degrading PEG hydrogels with high modulus: engineering gel structural changes to facilitate cartilaginous tissue production. Biotechnol Bioeng. 2004;86:747–55.
Xue JX, Gong YY, Zhou GD, Liu W, Cao Y, Zhang WJ. Chondrogenic differentiation of bone marrow-derived mesenchymal stem cells induced by acellular cartilage sheets. Biomaterials. 2012;33:5832–40.
Deng J, She R, Huang W, Dong Z, Mo G, Liu B. A silk fibroin/chitosan scaffold in combination with bone marrow-derived mesenchymal stem cells to repair cartilage defects in the rabbit knee. J Mater Sci Mater Med. 2013;24:2037–46.
Lim CT, Ren X, Afizah MH, Tarigan-Panjaitan S, Yang Z, Wu Y, et al. Repair of osteochondral defects with rehydrated freeze-dried oligo poly(ethylene glycol) fumarate hydrogels seeded with bone marrow mesenchymal stem cells in a porcine model. Tissue Eng Part A. 2013;19:1852–61.
Xue K, Qi L, Zhou G, Liu K. A two-step method of constructing mature cartilage using bone marrow-derived mesenchymal stem cells. Cells Tissues Organs. 2013;197:484–95.
Wang L, Tran I, Seshareddy K, Weiss ML, Detamore MS. A comparison of human bone marrow-derived mesenchymal stem cells and human umbilical cord-derived mesenchymal stromal cells for cartilage tissue engineering. Tissue Eng Part A. 2009;15:2259–66.
Li C, Wei G, Gu Q, Wen G, Qi B, Xu L, et al. Donor Age and cell passage affect osteogenic ability of rat bone marrow mesenchymal stem cells. Cell Biochem Biophys. 2015;72:543–9.
Li X, Li Y, Zuo Y, Qu D, Liu Y, Chen T, et al. Osteogenesis and chondrogenesis of biomimetic integrated porous PVA/gel/V-n-HA/pa6 scaffolds and BMSCs construct in repair of articular osteochondral defect. J Biomed Mater Res A. 2015;103:3226–36.
Zuk PA, Zhu M, Mizuno H, Huang J, Futrell JW, Katz AJ, et al. Multilineage cells from human adipose tissue: implications for cell-based therapies. Tissue Eng. 2001;7:211–28.
Yoon HH, Bhang SH, Shin J-Y, Shin J, Kim B-S. Enhanced cartilage formation via three-dimensional cell engineering of human adipose-derived stem cells. Tissue Eng Part A. 2012;18:1949–56.
Jung M-S, Jang HB, Lee S-E, Park J-H, Hwang Y-S. In vitro micro-mineralized tissue formation by the combinatory condition of adipose-derived stem cells, macroporous PLGA microspheres and a bioreactor. Macromol Res. 2014;22:47–57.
Veronesi F, Maglio M, Tschon M, Aldini NN, Fini M. Adipose-derived mesenchymal stem cells for cartilage tissue engineering: state-of-the-art in in vivo studies. J Biomed Mater Res A. 2014;102:2448–66.
Wang T, Lai JH, Han L-H, Tong X, Yang F. Chondrogenic differentiation of adipose-derived stromal cells in combinatorial hydrogels containing cartilage matrix proteins with decoupled mechanical stiffness. Tissue Eng Part A. 2014;20:2131–9.
Wang ZJ, An RZ, Zhao JY, Zhang Q, Yang J, Wang JB, et al. Repair of articular cartilage defects by tissue-engineered cartilage constructed with adipose-derived stem cells and acellular cartilaginous matrix in rabbits. Genet Mol Res. 2014;13:4599–606.
Shen J, Gao Q, Zhang Y, He Y. Autologous platelet-rich plasma promotes proliferation and chondrogenic differentiation of adipose-derived stem cells. Mol Med Rep. 2015;11:1298–303.
Tang X-B, Dong P-L, Wang J, Zhou H-Y, Zhang H-X, Wang S-Z. Effect of autologous platelet-rich plasma on the chondrogenic differentiation of rabbit adipose-derived stem cells in vitro. Exp Ther Med. 2015;10:477–83.
Cheng A, Kapacee Z, Peng J, Lu S, Lucas RJ, Hardingham TE, et al. Cartilage repair using human embryonic stem cell-derived chondroprogenitors. Stem Cells Transl Med. 2014;3:1287–94.
Toh WS, Lee EH, Guo X-M, Chan JKY, Yeow CH, Choo AB, et al. Cartilage repair using hyaluronan hydrogel-encapsulated human embryonic stem cell-derived chondrogenic cells. Biomaterials. 2010;31:6968–80.
Hwang NS, Varghese S, Elisseeff J. Cartilage tissue engineering—directed differentiation of embryonic stem cells in three-dimensional hydrogel culture. In: Vemuri MC, editor. Methods in molecular biology. New York: Humana Press; 2007. p. 351–73.
Pilichi S, Rocca S, Pool RR, Dattena M, Masala G, Mara L, et al. Treatment with embryonic stem-like cells into osteochondral defects in sheep femoral condyles. BMC Vet Res. 2014;10:301.
Wakitani S, Aoki H, Harada Y, Sonobe M, Morita Y, Mu Y, et al. Embryonic stem cells form articular cartilage, not teratomas, in osteochondral defects of rat joints. Cell Transplant. 2004;13:331–6.
Hwang NS, Varghese S, Elisseeff J. Derivation of chondrogenically-committed cells from human embryonic cells for cartilage tissue regeneration. PloS One. 2008;3:e2498.
Toh WS, Lee EH, Cao T. Potential of human embryonic stem cells in cartilage tissue engineering and regenerative medicine. Stem Cell Rev Rep. 2011;7:544–59.
Takahashi K, Tanabe K, Ohnuki M, et al. Induction of pluripotent stem cells from adult human fibroblasts by defined factors. Cell. 2007;131(5):861–72.
Takahashi K, Yamanaka S. Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors. Cell. 2006;126(4):663–76.
Lach MS, Rosochowicz MA, Richter M, Jagiello I, Suchorska WM, Trzeciak T. The induced pluripotent stem cells in articular cartilage regeneration and disease modelling: are we ready for their clinical use? Cell. 2022;11(3):529.
Nam Y, Rim YA, Jung SM, Ju JH. Cord blood cell-derived iPSCs as a new candidate for chondrogenic differentiation and cartilage regeneration. Stem Cell Res Ther. 2017;8:16.
Yamashita A, Morioka M, Yahara Y, et al. Generation of scaffoldless hyaline cartilaginous tissue from human iPSCs. Stem Cell Rep. 2015;4(3):404–18.
Kotaka S, Wakitani S, Shimamoto A, et al. Magnetic targeted delivery of induced pluripotent stem cells promotes articular cartilage repair. Stem Cells Int. 2017;2017:9514719.
Liu J, Nie HR, Xu ZL, et al. The effect of 3D nanofibrous scaffolds on the chondrogenesis of induced pluripotent stem cells and their application in restoration of cartilage defects. PloS One. 2014;9(11):111566.
Gronthos S, Mankani M, Brahim J, Robey PG, Shi S. Postnatal human dental pulp stem cells (DPSCs) in vitro and in vivo. Proc Natl Acad Sci U S A. 2000;97(25):13625–30.
Dai J, Wang J, Lu J, et al. The effect of co-culturing costal chondrocytes and dental pulp stem cells combined with exogenous FGF9 protein on chondrogenesis and ossification in engineered cartilage. Biomaterials. 2012;33(31):7699–711.
Mata M, Milian L, Oliver M, et al. In vivo articular cartilage regeneration using human dental pulp stem cells cultured in an alginate scaffold: a preliminary study. Stem Cells Int. 2017;2017:8309256.
Yanasse R, De Labio R, Marques L, et al. Xenotransplantation of human dental pulp stem cells in platelet-rich plasma for the treatment of full-thickness articular cartilage defects in a rabbit model. Exp Ther Med. 2019;17(6):4344–56.
Ding DC, Chang YH, Shyu WC, Lin SZ. Human umbilical cord mesenchymal stem cells: a new era for stem cell therapy. Cell Transplant. 2015;24(3):339–47.
Mennan C, Wright K, Bhattacharjee A, Balain B, Richardson J, Roberts S. Isolation and characterisation of mesenchymal stem cells from different regions of the human umbilical cord. Biomed Res Int. 2013;2013:916136.
Fong CY, Gauthaman K, Cheyyatraivendran S, Lin HD, Biswas A, Bongso A. Human umbilical cord Wharton’s jelly stem cells and its conditioned medium support hematopoietic stem cell expansion ex vivo. J Cell Biochem. 2012;113(2):658–68.
Zheng P, Hu X, Lou Y, Tang K. A rabbit model of osteochondral regeneration using three-dimensional printed polycaprolactone-hydroxyapatite scaffolds coated with umbilical cord blood mesenchymal stem cells and chondrocytes. Med Sci Monit. 2019;25:7361–9.
Song J-S, Hong K-T, Kong C-G, et al. High tibial osteotomy with human umbilical cord blood-derived mesenchymal stem cells implantation for knee cartilage regeneration. World J Stem Cells. 2020;12(6):514–26.
Yang H-Y, Song E-K, Kang S-J, Kwak W-K, Kang J-K, Seon J-K. Allogenic umbilical cord blood-derived mesenchymal stromal cell implantation was superior to bone marrow aspirate concentrate augmentation for cartilage regeneration despite similar clinical outcomes. Knee Surg Sports Traumatol Arthrosc. 2022;30(1):208–18.
Chang H, Tate MLK. Concise review: the periosteum: tapping into a reservoir of clinically useful progenitor cells. Stem Cells Transl Med. 2012;1:480–91.
De Bari C, Dell’Accio F, Tylzanowski P, Luyten FP. Multipotent mesenchymal stem cells from adult human synovial membrane. Arthritis Rheum. 2001;44:1928–42.
Liu Y, Buckley CT, Downey R, Mulhall KJ, Kelly DJ. The role of environmental factors in regulating the development of cartilaginous grafts engineered using osteoarthritic human infrapatellar fat pad–derived stem cells. Tissue Eng Part A. 2012;18:1531–41.
Richter W. Mesenchymal stem cells and cartilage in situ regeneration. J Intern Med. 2009;266:390–405.
Ogata Y, Mabuchi Y, Yoshida M, Suto EG, Suzuki N, Muneta T, et al. Purified human synovium mesenchymal stem cells as a good resource for cartilage regeneration. PloS One. 2015;10:e0129096.
Alegre-Aguaron E, Sampat SR, Xiong JC, Colligan RM, Bulinski JC, Cook JL, et al. Growth factor priming differentially modulates components of the extracellular matrix proteome in chondrocytes and synovium-derived stem cells. PloS One. 2014;9:e88053.
Chang CB, Han SA, Kim EM, Lee S, Seong SC, Lee MC. Chondrogenic potentials of human synovium-derived cells sorted by specific surface markers. Osteoarthr Cartil. 2013;21:190–9.
Chang C-H, Chen C-C, Liao C-H, Lin F-H, Hsu Y-M, Fang H-W. Human acellular cartilage matrix powders as a biological scaffold for cartilage tissue engineering with synovium-derived mesenchymal stem cells. J Biomed Mater Res A. 2014;102:2248–57.
Jones BA, Pei M. Synovium-derived stem cells: a tissue-specific stem cell for cartilage engineering and regeneration. Tissue Eng Part B Rev. 2012;18:301–11.
Suzuki S, Muneta T, Tsuji K, Ichinose S, Makino H, Umezawa A, et al. Properties and usefulness of aggregates of synovial mesenchymal stem cells as a source for cartilage regeneration. Arthritis Res Ther. 2012;14:R136.
Fan J, Ren L, Liang R, Gong Y, Cai D, Wang D-A. Chondrogenesis of synovium-derived mesenchymal stem cells in photopolymerizing hydrogel scaffolds. J Biomater Sci Polym Ed. 2010;21:1653–67.
Pei M, He F, Boyce BM, Kish VL. Repair of full-thickness femoral condyle cartilage defects using allogeneic synovial cell-engineered tissue constructs. Osteoarthr Cartil. 2009;17:714–22.
Demoor M, Ollitrault D, Gomez-Leduc T, Bouyoucef M, Hervieu M, Fabre H, et al. Cartilage tissue engineering: molecular control of chondrocyte differentiation for proper cartilage matrix reconstruction. Biochim Biophys Acta Gen Subj. 2014;1840:2414–40.
Lee S-H, Shin H. Matrices and scaffolds for delivery of bioactive molecules in bone and cartilage tissue engineering. Adv Drug Deliv Rev. 2007;59:339–59.
Angel MJ, Sgaglione NA, Grande DA. Clinical applications of bioactive factors in sports medicine—current concepts and future trends. Sports Med Arthrosc Rev. 2006;14:138–45.
Kawamura K, Chu CR, Sobajima S, Robbins PD, Fu FH, Izzo NJ, et al. Adenoviral-mediated transfer of TGF-β1 but not IGF-1 induces chondrogenic differentiation of human mesenchymal stem cells in pellet cultures. Exp Hematol. 2005;33:865–72.
Bian L, Zhai DY, Tous E, Rai R, Mauck RL, Burdick JA. Enhanced MSC chondrogenesis following delivery of TGF-β3 from alginate microspheres within hyaluronic acid hydrogels in vitro and in vivo. Biomaterials. 2011;32:6425–34.
Han Y, Wei Y, Wang S, Song Y. Cartilage regeneration using adipose-derived stem cells and the controlled-released hybrid microspheres. Joint Bone Spine. 2010;77:27–31.
Hildner F, Albrecht C, Gabriel C, Redl H, van Griensven M. State of the art and future perspectives of articular cartilage regeneration: a focus on adipose-derived stem cells and platelet-derived products. J Tissue Eng Regen Med. 2011;5:E36–51.
Lu C-H, Lin K-J, Chiu H-Y, Chen C-Y, Yen T-C, Hwang S-M, et al. Improved chondrogenesis and engineered cartilage formation from TGF-beta 3-expressing adipose-derived stem cells cultured in the rotating-shaft bioreactor. Tissue Eng Part A. 2012;18:2114–24.
Re’em T, Witte F, Willbold E, Ruvinov E, Cohen S. Simultaneous regeneration of articular cartilage and subchondral bone induced by spatially presented TGF-beta and BMP-4 in a bilayer affinity binding system. Acta Biomater. 2012;8:3283–93.
Pretzel D, Linss S, Ahrem H, Endres M, Kaps C, Klemm D, et al. A novel in vitro bovine cartilage punch model for assessing the regeneration of focal cartilage defects with biocompatible bacterial nanocellulose. Arthritis Res Ther. 2013;15:R59.
Lu C-H, Yeh T-S, Yeh C-L, Fang Y-HD, Sung L-Y, Lin S-Y, et al. Regenerating cartilages by engineered ASCs: prolonged TGF-beta 3/BMP-6 expression improved articular cartilage formation and restored zonal structure. Mol Ther. 2014;22:186–95.
Elmallah RK, Cherian JJ, Jauregui JJ, Pierce TP, Beaver WB, Mont MA. Genetically modified chondrocytes expressing TGF-beta 1: a revolutionary treatment for articular cartilage damage? Expert Opin Biol Ther. 2015;15:455–64.
Kim SH, Kim SH, Jung Y. TGF-beta(3) encapsulated PLCL scaffold by a supercritical CO2-HFIP co-solvent system for cartilage tissue engineering. J Control Release. 2015;206:101–7.
Murphy MK, Huey DJ, Hu JC, Athanasiou KA. TGF-beta 1, GDF-5, and BMP-2 stimulation induces chondrogenesis in expanded human articular chondrocytes and marrow-derived stromal cells. Stem Cells. 2015;33:762–73.
Zhang N, Lock J, Sallee A, Liu H. Magnetic nanocomposite hydrogel for potential cartilage tissue engineering: synthesis, characterization, and cytocompatibility with bone marrow derived mesenchymal stem cells. ACS Appl Mater Interfaces. 2015;7:20987–98.
Capito RM, Spector M. Collagen scaffolds for nonviral IGF-1 gene delivery in articular cartilage tissue engineering. Gene Ther. 2007;14:721–32.
Singh NK, Singh GR, Amarpal, Kinjavdekar P, Sharma AK, Mohanty TR. Articular cartilage repair with autografting under the influence of insulin-like growth factor-1 in rabbits. J Vet Med Ser A Physiol Pathol Clin Med. 2007;54:210–8.
Davies LC, Blain EJ, Gilbert SJ, Caterson B, Duance VC. The potential of IGF-1 and TGF beta 1 for promoting “Adult” articular cartilage repair: an in vitro study. Tissue Eng Part A. 2008;14:1251–61.
Bastiaansen-Jenniskens YM, Koevoet W, Feijt C, Bos PK, Verhaar JAN, Van Osch GJVM, et al. Proteoglycan production is required in initial stages of new cartilage matrix formation but inhibits integrative cartilage repair. J Tissue Eng Regen Med. 2009;3:117–23.
An C, Cheng Y, Yuan Q, Li J. IGF-1 and BMP-2 induces differentiation of adipose-derived mesenchymal stem cells into chondrocytes-like cells. Ann Biomed Eng. 2010;38:1647–54.
Liu XW, Hu J, Man C, Zhang B, Ma YQ, Zhu SS. Insulin-like growth factor-1 suspended in hyaluronan improves cartilage and subchondral cancellous bone repair in osteoarthritis of temporomandibular joint. Int J Oral Maxillofac Surg. 2011;40:184–90.
Spiller KL, Liu Y, Holloway JL, Maher SA, Cao Y, Liu W, et al. A novel method for the direct fabrication of growth factor-loaded microspheres within porous nondegradable hydrogels: controlled release for cartilage tissue engineering. J Control Release. 2012;157:39–45.
Joos H, Wildner A, Hogrefe C, Reichel H, Brenner RE. Interleukin-1 beta and tumor necrosis factor alpha inhibit migration activity of chondrogenic progenitor cells from non-fibrillated osteoarthritic cartilage. Arthritis Res Ther. 2013;15:R119.
Henson FMD, Vincent T. Chondrocyte outgrowth into a gelatin scaffold in a single impact load model of damage/repair—effect of BMP-2. BMC Musculoskelet Disord. 2007;8:120.
Kuo AC, Rodrigo JJ, Reddi AH, Curtiss S, Grotkopp E, Chiu M. Microfracture and bone morphogenetic protein 7 (BMP-7) synergistically stimulate articular cartilage repair. Osteoarthr Cartil. 2006;14:1126–35.
Matsumoto T, Cooper GM, Gharaibeh B, Meszaros LB, Li G, Usas A, et al. Cartilage repair in a rat model of osteoarthritis through intraarticular transplantation of muscle-derived stem cells expressing bone morphogenetic protein 4 and soluble Flt-1. Arthritis Rheum. 2009;60:1390–405.
Menendez MI, Clark DJ, Carlton M, Flanigan DC, Jia G, Sammet S, et al. Direct delayed human adenoviral BMP-2 or BMP-6 gene therapy for bone and cartilage regeneration in a pony osteochondral model. Osteoarthr Cartil. 2011;19:1066–75.
Nochi H, Sung JH, Lou J, Adkisson HD, Maloney WJ, Hruska KA. Adenovirus mediated BMP-13 gene transfer induces chondrogenic differentiation of murine mesenchymal progenitor cells. J Bone Miner Res. 2004;19:111–22.
Shi J, Zhang X, Zhu J, Pi Y, Hu X, Zhou C, et al. Nanoparticle delivery of the bone morphogenetic protein 4 gene to adipose-derived stem cells promotes articular cartilage repair in vitro and in vivo. Arthroscopy. 2013;29:2001–U182.
Yang HS, La W-G, Bhang SH, Kim H-J, Im G-I, Lee H, et al. Hyaline cartilage regeneration by combined therapy of microfracture and long-term bone morphogenetic protein-2 delivery. Tissue Eng Part A. 2011;17:1809–18.
Zhang Y, Tang CL, Chen WJ, Zhang Q, Wang SL. Dynamic compression combined with exogenous SOX-9 promotes chondrogenesis of adipose-derived mesenchymal stem cells in PLGA scaffold. Eur Rev Med Pharmacol Sci. 2015;19:2671–8.
Kaul G, Cucchiarini M, Arntzen D, Zurakowski D, Menger MD, Kohn D, et al. Local stimulation of articular cartilage repair by transplantation of encapsulated chondrocytes overexpressing human fibroblast growth factor 2 (FGF-2) in vivo. J Gene Med. 2006;8:100–11.
Takafuji H, Suzuki T, Okubo Y, Fujimura K, Bessho K. Regeneration of articular cartilage defects in the temporomandibular joint of rabbits by fibroblast growth factor-2: a pilot study. Int J Oral Maxillofac Surg. 2007;36:934–7.
Ellman MB, An HS, Muddasani P, Im H-J. Biological impact of the fibroblast growth factor family on articular cartilage and intervertebral disc homeostasis. Gene. 2008;420:82–9.
Kuroda Y, Akiyama H, Kawanabe K, Tabata Y, Nakamura T. Treatment of experimental osteonecrosis of the hip in adult rabbits with a single local injection of recombinant human FGF-2 microspheres. J Bone Miner Metab. 2010;28:608–16.
Maehara H, Sotome S, Yoshii T, Torigoe I, Kawasaki Y, Sugata Y, et al. Repair of large osteochondral defects in rabbits using porous hydroxyapatite/collagen (HAp/Col) and fibroblast growth factor-2 (FGF-2). J Orthop Res. 2010;28:677–86.
Kim JH, Lee MC, Seong SC, Park KH, Lee S. Enhanced proliferation and chondrogenic differentiation of human synovium-derived stem cells expanded with basic fibroblast growth factor. Tissue Eng Part A. 2011;17:991–1002.
Yuan L-J, Niu C-C, Lin S-S, Chan Y-S, Yang C-Y, Chen W-J, et al. Additive effects of hyperbaric oxygen and platelet-derived growth factor-BB in chondrocyte transplantation via up-regulation expression of platelet-derived growth factor-beta receptor. J Orthop Res. 2009;27:1439–46.
Shin SH, Song HY, Kim MY, Do EK, Kim KH, Kim JH. Platelet-activating factor receptor mediates oxidized low density lipoprotein-induced migration of bone marrow-derived mesenchymal stem cells. Cell Physiol Biochem. 2010;26:689–98.
Howard D, Shepherd JH, Kew SJ, Hernandez P, Ghose S, Wardale JA, et al. Release of growth factors from a reinforced collagen GAG matrix supplemented with platelet rich plasma: influence on cultured human meniscal cells. J Orthop Res. 2014;32:273–8.
Lee JM, Ryu JH, Kim EA, Jo S, Kim B-S, Lee H, et al. Adhesive barrier/directional controlled release for cartilage repair by endogenous progenitor cell recruitment. Biomaterials. 2015;39:173–81.
Liu X, Yang Y, Li Y, et al. Integration of stem cell-derived exosomes with in situ hydrogel glue as a promising tissue patch for articular cartilage regeneration. Nanoscale. 2017;9(13):4430–8.
Wu X, Wang Y, Xiao Y, Crawford R, Mao X, Prasadam I. Extracellular vesicles: potential role in osteoarthritis regenerative medicine. J Orthop Transl. 2020;21:73–80.
Jiang S, Tian G, Yang Z, et al. Enhancement of acellular cartilage matrix scaffold by Wharton’s jelly mesenchymal stem cell-derived exosomes to promote osteochondral regeneration. Bioact Mater. 2021;6(9):2711–28.
Shao J, Zhu J, Chen Y, et al. Exosomes from Kartogenin-pretreated infrapatellar fat pad mesenchymal stem cells enhance chondrocyte anabolism and articular cartilage regeneration. Stem Cells Int. 2021;2021:6624874.
Chen J, Huang T, Liu R, Wang C, Jiang H, Sun H. Congenital microtia patients: the genetically engineered exosomes released from porous gelatin methacryloyl hydrogel for downstream small RNA profiling, functional modulation of microtia chondrocytes and tissue-engineered ear cartilage regeneration. J Nanobiotechnol. 2022;20(1):164.
Krueger JP, Hondke S, Endres M, Pruss A, Siclari A, Kaps C. Human platelet-rich plasma stimulates migration and chondrogenic differentiation of human subchondral progenitor cells. J Orthop Res. 2012;30(6):845–52.
van Buul GM, Koevoet WLM, Kops N, et al. Platelet-rich plasma releasate inhibits inflammatory processes in osteoarthritic chondrocytes. Am J Sports Med. 2011;39(11):2362–70.
Sancho-Tello M, Martorell S, Mata Roig M, et al. Human platelet-rich plasma improves the nesting and differentiation of human chondrocytes cultured in stabilized porous chitosan scaffolds. J Tissue Eng. 2017;8:2041731417697545.
Lu H-T, Chang W-T, Tsai M-L, Chen C-H, Chen W-Y, Mi F-L. Development of injectable fucoidan and biological macromolecules hybrid hydrogels for intra-articular delivery of platelet-rich plasma. Mar Drugs. 2019;17(4):236.
Singh BN, Nallakumarasamy A, Sinha S, et al. Generation of hybrid tissue engineered construct through embedding autologous chondrocyte loaded platelet rich plasma/alginate based hydrogel in porous scaffold for cartilage regeneration. Int J Biol Macromol. 2022;203:389–405.
Scotti C, Mangiavini L, Boschetti F, Vitari F, Domeneghini C, Fraschini G, et al. Effect of in vitro culture on a chondrocyte-fibrin glue hydrogel for cartilage repair. Knee Surg Sports Traumatol Arthrosc. 2010;18:1400–6.
Deponti D, Di Giancamillo A, Mangiavini L, Pozzi A, Fraschini G, Sosio C, et al. Fibrin-based model for cartilage regeneration: tissue maturation from in vitro to in vivo. Tissue Eng Part A. 2012;18:1109–22.
Erickson IE, Kestle SR, Zellars KH, Dodge GR, Burdick JA, Mauck RL. Improved cartilage repair via in vitro pre-maturation of MSC-seeded hyaluronic acid hydrogels. Biomed Mater. 2012;7:024110.
Jeon JE, Schrobback K, Meinert C, Sramek V, Hutmacher DW, Klein TJ. Effect of preculture and loading on expression of matrix molecules, matrix metalloproteinases, and cytokines by expanded osteoarthritic chondrocytes. Arthritis Rheum. 2013;65:2356–67.
Sabatino MA, Santoro R, Gueven S, Jaquiery C, Wendt DJ, Martin I, et al. Cartilage graft engineering by co-culturing primary human articular chondrocytes with human bone marrow stromal cells. J Tissue Eng Regen Med. 2015;9:1394–403.
Zhao X, Bichara DA, Zhou L, Kulig KM, Tseng A, Bowley CM, et al. Conditions for seeding and promoting neo-auricular cartilage formation in a fibrous collagen scaffold. J Craniomaxillofac Surg. 2015;43:382–9.
Cao Y, Vacanti JP, Paige KT, Upton J, Vacanti CA. Transplantation of chondrocytes utilizing a polymer-cell construct to produce tissue-engineered cartilage in the shape of a human ear. Plast Reconstr Surg. 1997;100:297–302.
Freyria A-M, Cortial D, Ronzière M-C, Guerret S, Herbage D. Influence of medium composition, static and stirred conditions on the proliferation of and matrix protein expression of bovine articular chondrocytes cultured in a 3-D collagen scaffold. Biomaterials. 2004;25:687–97.
Darling EM, Athanasiou KA. Articular cartilage bioreactors and bioprocesses. Tissue Eng. 2003;9:9–26.
Shahin K, Doran PM. Strategies for enhancing the accumulation and retention of extracellular matrix in tissue-engineered cartilage cultured in bioreactors. PloS One. 2011;6:e23119.
Gaissmaier C, Koh JL, Weise K, Mollenhauer JA. Future perspectives of articular cartilage repair. Injury. 2008;39(Suppl 1):S114–20.
Zheng D, Chen T, Han L, et al. Synergetic integrations of bone marrow stem cells and transforming growth factor-beta 1 loaded chitosan nanoparticles blended silk fibroin injectable hydrogel to enhance repair and regeneration potential in articular cartilage tissue. Int Wound J. 2022;19(5):1023–38.
Dong X, Li C, Zhang M, et al. Multifunctional injectable hydrogel for effective promotion of cartilage regeneration and protection against osteoarthritis: combined chondroinductive, antioxidative and anti-inflammatory strategy. Sci Technol Adv Mater. 2022;23(1):361–75.
Dong Y, Liu Y, Chen Y, et al. Spatiotemporal regulation of endogenous MSCs using a functional injectable hydrogel system for cartilage regeneration. NPG Asia Mater. 2021;13(1):71.
Bauge C, Boumediene K. Use of adult stem cells for cartilage tissue engineering: current status and future developments. Stem Cells Int. 2015;2015:438026.
Fioretta ES, Fledderus JO, Burakowska-Meise EA, Baaijens F, Verhaar MC, Bouten CV. Polymer–based scaffold designs for in situ vascular tissue engineering: controlling recruitment and differentiation behavior of endothelial colony forming cells. Macromol Biosci. 2012;12:577–90.
Vanden Berg-Foels WS. In situ tissue regeneration: chemoattractants for endogenous stem cell recruitment. Tissue Eng. 2013;45:e57.
Kon E, Roffi A, Filardo G, Tesei G, Marcacci M. Scaffold-based cartilage treatments: with or without cells? A systematic review of preclinical and clinical evidence. Arthroscopy. 2015;31:767–75.
Wang W, Sun L, Zhang P, Song J, Liu W. An anti-inflammatory cell-free collagen/resveratrol scaffold for repairing osteochondral defects in rabbits. Acta Biomater. 2014;10:4983–95.
Dai Y, Liu G, Ma L, Wang D, Gao C. Cell-free macro-porous fibrin scaffolds for in situ inductive regeneration of full-thickness cartilage defects. J Mater Chem B. 2016;4:4410–9.
Dai Y, Shen T, Ma L, Wang D, Gao C. Regeneration of osteochondral defects in vivo by a cell-free cylindrical poly(lactide-co-glycolide) scaffold with a radially oriented microstructure. J Tissue Eng Regen Med. 2018;12(3):1647–61.
Dai Y, Gao Z, Ma L, Wang D, Gao C. Cell-free HA-MA/PLGA scaffolds with radially oriented pores for in situ inductive regeneration of full thickness cartilage defects. Macromol Biosci. 2016;16(11):1632–42.
Roessler PP, Pfister B, Gesslein M, Figiel J, Heyse TJ, Colcuc C, et al. Short-term follow up after implantation of a cell-free collagen type I matrix for the treatment of large cartilage defects of the knee. Int Orthop. 2015;39:2473–9.
Madry H, van Dijk CN, Mueller-Gerbl M. The basic science of the subchondral bone. Knee Surg Sports Traumatol Arthrosc. 2010;18:419–33.
Gelse K, Klinger P, Koch M, Surmann-Schmitt C, von der Mark K, Swoboda B, et al. Thrombospondin-1 prevents excessive ossification in cartilage repair tissue induced by osteogenic protein-1. Tissue Eng Part A. 2011;17:2101–12.
Ghosh S, Viana J, Reis R, Mano J. Bi-layered constructs based on poly (L-lactic acid) and starch for tissue engineering of osteochondral defects. Mater Sci Eng C. 2008;28:80–6.
Nukavarapu SP, Dorcemus DL. Osteochondral tissue engineering: current strategies and challenges. Biotechnol Adv. 2013;31:706–21.
Chen GP, Sato T, Tanaka J, Tateishi T. Preparation of a biphasic scaffold for osteochondral tissue engineering. Mater Sci Eng C Biomim Supramol Syst. 2006;26:118–23.
Jiang C-C, Chiang H, Liao C-J, Lin Y-J, Kuo T-F, Shieh C-S, et al. Repair of porcine articular cartilage defect with a biphasic osteochondral composite. J Orthop Res. 2007;25:1277–90.
Yang Q, Peng J, Lu S-b, Guo Q-y, Zhao B, Zhang L, et al. Evaluation of an extracellular matrix-derived acellular biphasic scaffold/cell construct in the repair of a large articular high-load-bearing osteochondral defect in a canine model. Chin Med J (Engl). 2011;124:3930–8.
Duan X, Zhu X, Dong X, Yang J, Huang F, Cen S, et al. Repair of large osteochondral defects in a beagle model with a novel type I collagen/glycosaminoglycan-porous titanium biphasic scaffold. Mater Sci Eng C Mater Biol Appl. 2013;33:3951–7.
Liu S, Wu J, Liu X, Chen D, Bowlin GL, Cao L, et al. Osteochondral regeneration using an oriented nanofiber yarn-collagen type I/hyaluronate hybrid/TCP biphasic scaffold. J Biomed Mater Res A. 2015;103:581–92.
Jeon JE, Vaquette C, Klein TJ, Hutmacher DW. Perspectives in multiphasic osteochondral tissue engineering. Anat Rec Adv Integr Anat Evol Biol. 2014;297:26–35.
Jang K-M, Lee J-H, Park CM, Song H-R, Wang JH. Xenotransplantation of human mesenchymal stem cells for repair of osteochondral defects in rabbits using osteochondral biphasic composite constructs. Knee Surg Sports Traumatol Arthrosc. 2014;22:1434–44.
Filardo G, Kon E, Perdisa F, Balboni F, Marcacci M. Autologous osteochondral transplantation for the treatment of knee lesions: results and limitations at two years’ follow-up. Int Orthop. 2014;38:1905–12.
Zhang S, Chen L, Jiang Y, Cai Y, Xu G, Tong T, et al. Bi-layer collagen/microporous electrospun nanofiber scaffold improves the osteochondral regeneration. Acta Biomater. 2013;9:7236–47.
Castro NJ, Patel R, Zhang LG. Design of a novel 3D printed bioactive nanocomposite scaffold for improved osteochondral regeneration. Cel Mol Bioeng. 2015;8:416–32.
Kim SH, Kim SH, Jung Y. Bi-layered PLCL/(PLGA/beta-TCP) composite scaffold for osteochondral tissue engineering. J Bioact Compat Polym. 2015;30:178–87.
Kon E, Filardo G, Shani J, Altschuler N, Levy A, Zaslav K, et al. Osteochondral regeneration with a novel aragonite-hyaluronate biphasic scaffold: up to 12-month follow-up study in a goat model. J Orthop Surg Res. 2015;10:81.
Koo Y, Choi E-J, Lee J, Kim H-J, Kim G, Do SH. 3D printed cell-laden collagen and hybrid scaffolds for in vivo articular cartilage tissue regeneration. J Ind Eng Chem. 2018;66:343–55.
Parisi C, Salvatore L, Veschini L, et al. Biomimetic gradient scaffold of collagen-hydroxyapatite for osteochondral regeneration. J Tissue Eng. 2020;11:2041731419896068.
Gostynska N, Krishnakumar GS, Campodoni E, et al. 3D porous collagen scaffolds reinforced by glycation with ribose for tissue engineering application. Biomed Mater. 2017;12(5):055002.
Kankala RK, Lu F-J, Liu C-G, Zhang S-S, Chen A-Z, Wang S-B. Effect of Icariin on Engineered 3D-printed porous scaffolds for cartilage repair. Materials. 2018;11(8):1390.
Guan J, Yuan F-z, Mao Z-m, et al. Fabrication of 3D-printed interpenetrating hydrogel scaffolds for promoting chondrogenic differentiation. Polymers. 2021;13(13):2146.
Li Q, Xu S, Feng Q, et al. 3D printed silk-gelatin hydrogel scaffold with different porous structure and cell seeding strategy for cartilage regeneration. Bioact Mater. 2021;6(10):3396–410.
Nelson M, Li S, Page SJ, et al. 3D printed silica-gelatin hybrid scaffolds of specific channel sizes promote collagen type II, Sox9 and Aggrecan production from chondrocytes. Mater Sci Eng C. 2021;123:111964.
Posniak S, Chung JHY, Liu X, et al. Bioprinting of chondrocyte stem cell co-cultures for auricular cartilage regeneration. Acs Omega. 2022;7(7):5908–20.
Chen W, Xu Y, Li Y, et al. 3D printing electrospinning fiber-reinforced decellularized extracellular matrix for cartilage regeneration. Chem Eng J. 2020;382:122986.
Zhou X, Nowicki M, Cui H, et al. 3D bioprinted graphene oxide-incorporated matrix for promoting chondrogenic differentiation of human bone marrow mesenchymal stem cells. Carbon. 2017;116:615–24.
Yang Y, Yang G, Song Y, Xu Y, Zhao S, Zhang W. 3D bioprinted integrated osteochondral scaffold-mediated repair of articular cartilage defects in the rabbit knee. J Med Biol Eng. 2020;40(1):71–81.
Deng C, Yang J, He H, et al. 3D bio-printed biphasic scaffolds with dual modification of silk fibroin for the integrated repair of osteochondral defects. Biomater Sci. 2021;9(14):4891–903.
Cao Y, Cheng P, Sang S, et al. 3D printed PCL/GelMA biphasic scaffold boosts cartilage regeneration using co-culture of mesenchymal stem cells and chondrocytes: in vivo study. Mater Des. 2021;210:110065.
Levato R, Webb WR, Otto IA, et al. The bio in the ink: cartilage regeneration with bioprintable hydrogels and articular cartilage-derived progenitor cells. Acta Biomater. 2017;61:41–53.
Ding X, Gao J, Yu X, et al. 3D-printed porous scaffolds of hydrogels modified with TGF-beta 1 binding peptides to promote in vivo cartilage regeneration and animal gait restoration. ACS Appl Mater Interfaces. 2022;14(14):15982–95.
Thunsiri K, Pitjamit S, Pothacharoen P, Pruksakorn D, Nakkiew W, Wattanutchariya W. The 3D-printed bilayer’s bioactive-biomaterials scaffold for full-thickness articular cartilage defects treatment. Materials. 2020;13(15):3417.
Qin C, Ma J, Chen L, et al. 3D bioprinting of multicellular scaffolds for osteochondral regeneration. Mater Today. 2021;49:68–84.
Shie M-Y, Chang W-C, Wei L-J, et al. 3D printing of cytocompatible water-based light-cured polyurethane with hyaluronic acid for cartilage tissue engineering applications. Materials. 2017;10(2):136.
Fu Y, Zoetebier B, Both S, Dijkstra PJ, Karperien M. Engineering of optimized hydrogel formulations for cartilage repair. Polymers. 2021;13(9):1526.
Gorronogoitia I, Urtaza U, Zubiarrain-Laserna A, Alonso-Varona A, Zaldua AM. A study of the printability of alginate-based bioinks by 3D bioprinting for articular cartilage tissue engineering. Polymers. 2022;14(2):354.
Zhang H, Huang H, Hao G, et al. 3D printing hydrogel scaffolds with nanohydroxyapatite gradient to effectively repair osteochondral defects in rats. Adv Funct Mater. 2021;31(1):2006697.
Cao Y, Cheng P, Sang S, et al. Mesenchymal stem cells loaded on 3D-printed gradient poly(epsilon)-caprolactonelimethacrylated alginate composite scaffolds for cartilage tissue engineering. Regener Biomater. 2021;8(3):rbab019.
Olubamiji AD, Zhu N, Chang T, et al. Traditional invasive and synchrotron-based noninvasive assessments of three-dimensional-printed hybrid cartilage constructs in situ. Tissue Eng Part C Methods. 2017;23(3):156–68.
Ryu J, Brittberg M, Nam B, et al. Evaluation of three-dimensional bioprinted human cartilage powder combined with micronized subcutaneous adipose tissues for the repair of osteochondral defects in Beagle dogs. Int J Mol Sci. 2022;23(5):2743.
Chen M, Li Y, Liu S, et al. Hierarchical macro-microporous WPU-ECM scaffolds combined with microfracture promote in situ articular cartilage regeneration in rabbits. Bioact Mater. 2021;6(7):1932–44.
Meng Y, Cao J, Chen Y, Yu Y, Ye L. 3D printing of a poly(vinyl alcohol)-based nano-composite hydrogel as an artificial cartilage replacement and the improvement mechanism of printing accuracy. J Mater Chem B. 2020;8(4):677–90.
Chen Y-W, Shie M-Y, Chang W-C, Shen Y-F. Approximate optimization study of light curing waterborne polyurethane materials for the construction of 3D printed cytocompatible cartilage scaffolds. Materials. 2021;14(22):6804.
Camacho P, Behre A, Fainor M, Seims KB, Chow LW. Spatial organization of biochemical cues in 3D-printed scaffolds to guide osteochondral tissue engineering. Biomater Sci. 2021;9(20):6813–29.
Li S, Tallia F, Mohammed AA, Stevens MM, Jones JR. Scaffold channel size influences stem cell differentiation pathway in 3-D printed silica hybrid scaffolds for cartilage regeneration. Biomater Sci. 2020;8(16):4458–66.
Shu C, Qin C, Chen L, et al. Metal-organic framework functionalized bioceramic scaffolds with antioxidative activity for enhanced osteochondral regeneration. Adv Sci. 2023;10:2206875.
Dang W, Wang X, Li J, et al. 3D printing of Mo-containing scaffolds with activated anabolic responses and bi-lineage bioactivities. Theranostics. 2018;8(16):4372–92.
Han YT, Wei QQ, Chang PB, et al. Three-dimensional printing of hydroxyapatite composites for biomedical application. Crystals. 2021;11(4):353.
Hsieh Y-H, Shen B-Y, Wang Y-H, Lin B, Lee H-M, Hsieh M-F. Healing of osteochondral defects implanted with biomimetic scaffolds of poly(epsilon-Caprolactone)/Hydroxyapatite and Glycidyl-Methacrylate-modified hyaluronic acid in a minipig. Int J Mol Sci. 2018;19(4):1125.
Bohner M, Santoni BLG, Dobelin N. Beta-tricalcium phosphate for bone substitution: synthesis and properties. Acta Biomater. 2020;113:23–41.
Rutgers M, van Pelt MJP, Dhert WJA, Creemers LB, Saris DBF. Evaluation of histological scoring systems for tissue-engineered, repaired and osteoarthritic cartilage. Osteoarthr Cartil. 2010;18:12–23.
Mankin HJ, LIPPIELLO L. Biochemical and metabolic abnormalities in articular cartilage from osteo-arthritic human hips. J Bone Joint Surg Am. 1970;52:424–34.
Lahm A, Uh M, Erggelet C, Haberstroh J, Mrosek E. Articular cartilage degeneration after acute subchondral bone damage—an experimental study in dogs with histopathological grading. Acta Orthop Scand. 2004;75:762–7.
Pearson RG, Kurien T, Shu KSS, Scammell BE. Histopathology grading systems for characterisation of human knee osteoarthritis—reproducibility, variability, reliability, correlation, and validity. Osteoarthr Cartil. 2011;19:324–31.
Custers RJH, Creemers LB, Verbout AJ, van Rijen MHP, Dhert WJA, Saris DBF. Reliability, reproducibility and variability of the traditional histologic/histochemical grading system vs the new OARSI osteoarthritis cartilage histopathology assessment system. Osteoarthr Cartil. 2007;15:1241–8.
Pritzker K, Gay S, Jimenez S, Ostergaard K, Pelletier J-P, Revell P, et al. Osteoarthritis cartilage histopathology: grading and staging. Osteoarthr Cartil. 2006;14:13–29.
O’Driscoll SW, Keeley FW, Salter RB. Durability of regenerated articular cartilage produced by free autogenous periosteal grafts in major full-thickness defects in joint surfaces under the influence of continuous passive motion. A follow-up report at one year. J Bone Joint Surg Am. 1988;70:595–606.
Pineda S, Pollack A, Stevenson S, Goldberg V, Caplan A. A semiquantitative scale or histologic grading of articular cartilage repair. Cells Tissues Organs. 1992;143:335–40.
Wakitani S, Goto T, Pineda SJ, Young RG, Mansour JM, Caplan AI, et al. Mesenchymal cell-based repair of large, full-thickness defects of articular cartilage. J Bone Joint Surg Am. 1994;76:579–92.
Roberts S, McCall IW, Darby AJ, Menage J, Evans H, Harrison PE, et al. Autologous chondrocyte implantation for cartilage repair: monitoring its success by magnetic resonance imaging and histology. Arthritis Res Ther. 2002;5:1.
Mainil-Varlet P, Aigner T, Brittberg M, Bullough P, Hollander A, Hunziker E, et al. Histological assessment of cartilage repair. J Bone Joint Surg Am. 2003;85:45–57.
Mainil-Varlet P, Van Damme B, Nesic D, Knutsen G, Kandel R, Roberts S. A new histology scoring system for the assessment of the quality of human cartilage repair: ICRS II. Am J Sports Med. 2010;38:880–90.
Hoemann CD, Tran-Khanh N, Chevrier A, Chen G, Lascau-Coman V, Mathieu C, et al. Chondroinduction is the main cartilage repair response to microfracture and microfracture with BST-CarGel: results as shown by ICRS-II histological scoring and a novel zonal collagen type scoring method of human clinical biopsy specimens. Am J Sports Med. 2015;43:2469–80.
O’Driscoll SW, Marx RG, Beaton DE, Miura Y, Gallay SH, Fitzsimmons JS. Validation of a simple histological-histochemical cartilage scoring system. Tissue Eng. 2001;7:313–20.
Grogan SP, Barbero A, Winkelmann V, Rieser F, Fitzsimmons JS, O’Driscoll S, et al. Visual histological grading system for the evaluation of in vitro-generated neocartilage. Tissue Eng. 2006;12:2141–9.
Bonasia DE, Marmotti A, Mattia S, Cosentino A, Spolaore S, Governale G, et al. The degree of chondral fragmentation affects extracellular matrix production in cartilage autograft implantation: an in vitro study. Arthroscopy. 2015;31:2335–41.
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Dai, Y., Gao, C. (2023). Cartilage Regeneration. In: Gao, C. (eds) Polymeric Biomaterials for Tissue Regeneration. Springer, Singapore. https://doi.org/10.1007/978-981-99-6948-7_9
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