Abstract
The tensile properties of mitral valve chordae tendineae derive from their structural make-up. The objectives of this study were to compare the stress relaxation properties of different types of chordae and relate their variation to structural features. Fifty chordae from eight hearts were subjected to stress relaxation tests. The percent stress relaxation and the relaxation rates were found to increase in the order of marginal, basal, and strut chordae. The water content of the three types of chordae was the same (marginal 77.1 ± 5.9%, basal 77.0 ± 3.4%, strut 78.0 ± 2.3% wet weight). The collagen, elastin, and glycosaminoglycan (GAG) content in chordae were quantified using hydroxyproline assay, fastin elastin assay, and fluorophore-assisted carbohydrate electrophoresis, respectively. Collagen content of marginal chordae was only slightly less than that of basal and strut chordae (marginal 56.6 ± 8.2%, basal 61.4 ± 5.6%, strut 63.8 ± 3.9% dry weight). There was also no significant difference in elastin content between the chordae (marginal 5.3 ± 3.2%, basal 5.4 ± 2.7%, strut 4.6 ± 1.7% dry weight). However, the concentrations of unsulfated chondroitin/dermatan sulfate, 6-sulfated chondroitin sulfate, and 4-sulfate chondroitin sulfate significantly decreased in the order of marginal, basal, and strut. The total GAG-content also decreased in the order of marginal, basal, and strut (p = 0.06). The greater amount of GAGs in marginal versus strut chordae is consistent with our previous observations that marginal chordae have a greater collagen fibril density and thus more GAG-mediated, fibril-to-fibril linkages. The greater number of proteoglycan linkages may prevent the slippage of fibrils with respect to each other, and thus reduce stress relaxation. The different viscoelastic properties of mitral valve chordae can thus be explained morphologically.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
REFERENCES
Atkinson, T. S., B. J. Ewers, and R. C. Haut. The tensile and stress relaxation responses of human patellar tendon varies with specimen cross-sectional area. J.Biomech. 32:907–914, 1999.
Bashey, R. I., and S. A. Jimenez. Collagen in heart valves. In: Collagen, edited by M. E. Nimni. Boca Raton, FL: CRC Press, 1988, Vol. 1, pp. 273–292.
Brown, A. N., B. S. Kim, E. Alsberg, and D. J. Mooney. Com-bining chondrocytes and smooth muscle cells to engineer hybrid soft tissue constructs. Tissue Eng. 6:297–305, 2000
Calabro, A., M. Benavides, M. Tammi, V. C. Hascall, and R. J. Midura. Microanalysis of enzyme digests of hyaluronan and chondroitin/dermatan sulfate by fluorophore-assisted carbohy-drate electrophoresis (FACE). Glycobiology 10:273–281, 2000.
Calabro, A., V. C. Hascall, and R. J. Midura. Adaptation of FACE methodology for microanalysis of total hyaluronan and chondroitin sulfate composition from cartilage. Glycobiology 10:283–293, 2000.
Carpentier, A. Cardiac valve surgery: The 'French correction.' J.Thorac.Cardiovasc.Surg. 79:323–337, 1983.
Carpentier, A., S. Chauvaud, and J. A. N. Fabiani. Reconstructive surgery of mitral valve incompetence: Ten-year appraisal. J.Thorac.Cardiovasc.Surg. 79:338, 1980.
Cribb, A. M., and J. E. Scott. Tendon response to tensile stress: An ultrastructural investigation of collagen: Proteoglycan interactions in stressed tendon. J.Anat. 187:423–428, 1995.
Dale, W. C., E. Baer, A. Keller, and R. R. Kohn. On the ultrastructure of mammalian tendon. Experientia 28:1293–1295, 1972.
Elliott, D. M., P. S. Robinson, J. A. Gimbel, J. J. Sarver, J. A. Abboud, and R. V. Iozzo, L. J. Soslowsky. Effect of altered matrix proteins on quasilinear viscoelastic properties in transgenic mouse tail tendons. Ann.Biomed.Eng. 31:599–605, 2003.
Erlinger, R. U., U. Welsch, and J. E. Scott. Ultrastructural and biochemical observations on proteoglycans and collagen in the mutable connective tissue of the feather star Antedon bifida (Echinodermata, Crinoidea). J.Anat. 183:1–11, 1993.
Grande-Allen, K. J., N. Ratliff, D. M. Cosgrove, III, B. P. Griffin, and I. Vesely. Myxomatous mitral valve chordae. II: Selective elevation of glycosaminoglycan content. J.Heart Valve Dis. 10:325–332, discussion 332–333, 2001.
Haut, R. C., and R. W. Little. Aconstitutive equation for collagen fibers. J.Biomech. 5:423–430, 1972.
He, Z., M. S. Sacks, L. Baijens, S. Wanant, P. Shah, and A. P. Yoganathan. Effects of papillary muscle position on in-vitro dynamic strain on the porcine mitral valve. J.Heart Valve Dis. 12:488–494, 2003.
Hubbard, R. P., and R. W. Soutas-Little. Mechanical properties of human tendon and their age dependence. J.Biomech.Eng. 106:144–150, 1984.
Kunzelman, K. S., and R. P. Cochran. Mechanical properties of basal and marginal mitral valve chordae tendineae. ASAIO Trans. 36:M405–M408, 1990.
Kwan, M. K., T. H. Lin, and S. L. Woo. On the viscoelastic properties of the anteromedial bundle of the anterior cruciate ligament. J.Biomech. 26:447–452, 1993.
Lam, J. H. C., N. Ranganthan, E. D. Wigle, and M. D. Silver. Morphology of the human mitral valve I—Chordae tendineae: A new classification. Circulation XLI:449–458, 1970
Lanir, Y. Amicrostructure model for the rheology of mammalian tendon. J.Biomech.Eng. 102:332–339, 1980.
Liao, J. Chapter 5: The role of small proteoglycan in fibril-to-fibril interaction. In Mechanical and Structural Properties of Mitral Valve Chordae Tendineae, Doctoral Dissertation, Cleveland State University. 2003.
Liao, J., and I. Vesely. A structural basis for the size-related mechanical properties of mitral valve chordae tendineae. J.Biomech. 36:1125–1133, 2003.
Lim, K. O., and D. R. Boughner. Mechanical properties of human mitral valve chordae tendineae: Variation with size and strain rate. Can.J.Physiol. 53:330–339, 1975.
Lis, Y., M. C. Burleigh, D. J. Parker, A. H. Child, J. Hogg, and M. J. Davies. Biochemical characterization of individual normal, floppy and rheumatic human mitral valves. Biochem.J. 244:597–603, 1987.
Murakami, T., T. Yagihara, F. Yamamoto, H. Uemura, K. Yamashita, and T. Ishizaka. Artificial chordae for mitral valve reconstruction in children. Ann.Thorac.Surg. 65:1377–1380, 1998.
Nishimura, M., W. Yan, Y. Mukudai, S. Nakamura, K. Nakamasu, M. Kawata, T. Kawamoto, M. Noshiro, T. Hamada, and Y. Kato. Role of chondroitin sulfate-hyaluronan interactions in the viscoelastic properties of extracellular matri-ces and fluids. Biochim.Biophys.Acta 1380:1–9, 1998.
Obadia, J. F., C. Casali, J. F. Chassignolle, and M. Janier. Mitral subvalvular apparatus: Different functions of primary and secondary chordae. Circulation 96:3124–3128, 1997.
Perloff, J. K., and W. C. Roberts. The mitral valve apparatus: Functional anatomy of mitral valve regurgitation. Circulation XLVI:227–239, 1972.
Pins, G. D., D. L. Christiansen, R. Patel, and F. H. Silver. Self-assembly of collagen fibers. Influence of fibrillar alignment and decorin on mechanical properties. Biophys.J. 73:2164–2217, 1997.
Pioletti, D. P., and L. R. Rakotomanana. On the independence of time and strain effects in the stress relaxation of ligaments and tendons. J.Biomech. 33:1729–1732, 2000.
Provenzano, P., R. Lakes, T. Keenan, R. Vanderby, Jr. Non-linear ligament viscoelasticity. Ann.Biomed.Eng. 29:908–914, 2001.
Ranganthan, N., J. H. Lam, E. D. Wigle, and M.D Silver. Morphology of the human mitral valve II—The valve leaflets. Circulation XLI:459–567, 1970.
Sauren, A. A., M. C. van Hout, A. A. van Steenhoven, F. E. Veldpaus, and J. D. Janssen. The mechanical properties of porcine aortic valve tissues. J.Biomech. 16:327–337, 1983.
Scott, J. E. Supramolecular organization of extracellular matrix glycosaminoglycans, in vitro and in the tissues. FASEB J. 6:2639–2645, 1992.
Scott, J. E. Proteodermatan and proteokeratan sulfate (decorin, lumican/fibromodulin) proteins are horseshoe shaped. Implications for their interactions with collagen. Biochemistry 35:8795–8799, 1996.
Scott, J. E., C. R. Orford, and E. Hughes. Proteoglycan-collagen arrangements in developing rat tail tendon: An electron micro-scopical and biochemical investigation. Biochem.J. 218:229, 1984.
Silver, F. H., Y. P. Kato, M. Ohno, and A. J. Wasserman. Analysis of mammalian connective tissue: Relationship between hierar-chical structures and mechanical properties. J.Long Term Eff.Med.Implants 2:165–198, 1992.
Silverman, M. E., and J. W. Hurst. The mitral complex: Inter-action of the anatomy, physiology, and pathology of the mitral annulus, mitral valve leaflets, chordae tendineae, and papillary muscles. Am.Heart J. 76:399–418, 1968.
Smedira, N. G., R. Selman, D. M. Cosgrove, P. M. McCarthy, B. W. Lytle, P. C. Taylor, C. Apperson-Hansen, R. W. Stewart, and F. D. Loop. Repair of anterior leaflet prolapse: Chordal transfer is superior to chordal shortening. J.Thorac.Cardiovasc.Surg. 112:287–291, discussion 291–292, 1996.
Soden, P. D., and I. Kershaw. Tensile testing of connective tissues. Med.Biol.Eng. 12:510–518, 1974.
Stegemann, H., and K. Stalder. Determination of hydroxyproline. Clin.Chim.Acta 18:267–273, 1967.
Wight, T. N., D. K. Heinegard, and V. C. Hascall. Proteoglycans: Structure and function. In: Cell Biology of Extracellular Matrix, 2nd edn., edited by E. D. Hay. New York: Plenum, 1991, pp. 45–77.
Yamamoto, E., K. Hayashi, and N. Yamamoto. Mechanical properties of collagen fascicles from the rabbit patellar tendon. J.Biomech.Eng. 121:124–131, 1999.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Liao, J., Vesely, I. Relationship Between Collagen Fibrils, Glycosaminoglycans, and Stress Relaxation in Mitral Valve Chordae Tendineae. Annals of Biomedical Engineering 32, 977–983 (2004). https://doi.org/10.1023/B:ABME.0000032460.97278.e9
Issue Date:
DOI: https://doi.org/10.1023/B:ABME.0000032460.97278.e9