Abstract
In 2009, Xu et al. and Chaput et al. in Nature Medicine had argued that the main cause of death in sepsis is the release from neutrophil nets of nuclear histone, highly toxic to endothelial cells and that these polycations are major and unique virulence factors. Since 2009, numerous researchers have also suggested the involvement of histones in the pathophysiology of many clinical disorders. If histones are indeed major unique virulence toxic agents, then heparin, activated protein C and antibodies to histone should prove excellent antisepsis agents. However, this is provided that these agents are administered to patients early enough before the activation of the cytokine storms, immune responses and the coagulation cascades are irreversibly unleashed. This may not be practical, since a diagnosis of sepsis is usually made much later. Future identifications of novel early markers are therefore needed and a compilation of cocktails of antagonists may replace the faulty single antagonists tried for many years, but in vain, to prevent death in sepsis.
Avoid common mistakes on your manuscript.
Circulating histones in sepsis and in post-traumatic events
Two “breakthrough” articles in Nature Medicine from 2009 (Chaput and Zychlinsky 2009; Xu et al. 2009) had argued to be the first to suggest that the main cause of death in sepsis may be the release from neutrophil extracellular traps (NETosis) of highly cationic histones possessing high toxicity to endothelial cells. This commences immunological (cytokines storms) and coagulation cascades culminating in septic shock and death. In their study, Xu et al. showed that activated protein C (APC), a protease, cleaved histones and reduced lethality. However, blockade of APC activation exacerbated sub-lethal LPS challenge into lethality, which was reversed by antibody to histone. Chaput et al. assessed the protective effects of recombinant thrombomodulin (rTM), which was approved in Japan for the treatment of disseminated intravascular coagulation (DIC) and is currently undergoing a phase III clinical trial in the USA.
Both groups of investigators had concluded and advised that extracellular histones may be the potential molecular targets for therapeutics for sepsis and additional post-infectious inflammatory and traumatic manifestations. If substantiated, the possibility that histone neutralization by heparins, but especially by the newly reported non-anticoagulant heparin (Wildhagen et al. 2014), may be a blessed future hope for critical care patients combating post-infectious and inflammatory sequelae.
It may interest the readers that already during the years 1951–1965, Katchalski’s group at the Weizmann Institute of Science in Rehovot, Israel, had described for the first time that the histone mimics poly-l-lysine and poly-l-arginine, injured blood vessels of rats, retarded blood coagulation and inhibited fibrinolysis (Biezunski et al. 1955; De Vries et al. 1953, 1956; Ginsburg et al. 1952). Also, during the years 1986–1996, investigators at the Department of Pathology, the University of Michigan, Ann Arbor, USA, at the Institute for Drug Research, School of Pharmacy and at the Institute for Dental Sciences at the Hebrew University of Jerusalem, Israel, had already described the killing of human umbilical cord endothelial cells by histone and by additional polycations, especially if combined synergistically with oxidants (Ginsburg et al. 1989; Ginsburg and Kohen 1995; Ginsburg et al. 1992, 1993). In those years, we never dreamed that many years later, we shall again address the histone issue thought central in the pathogenesis of so many clinical disorders.
It may be pictured that polymorphonuclear leukocytes (PMNs) recruited in sepsis, which are attracted to and adhere to endothelial cells, undergo activation and release not only highly cationic histones, LL-37 and elastase, but also a plethora of pro-inflammatory agonist such as oxidants, superoxide, nitric oxide, peroxynitrite, MPO-catalyzed hypochlorous acid, phospholipases A2 as well as numerous acid hydrolases, which may act synergistically to permeabilize and destroy endothelial cells.
Therefore, the concept that histones may exclusively act as a unique virulence factor should be doubted and reconsidered, since toxic histones probably never act on their own but always in synergy with many of the pro-inflammatory agonists released by activated neutrophils.
Since 2009, a large number of publications had also claimed a possible major involvement of nuclear histones, citrullinated histone and histone deacetylase in the pathogenesis of cardiovascular, hepatic, pulmonary and renal disorders as well as in post-traumatic episodes (Alhamdi and Toh 2016; Birmpas et al. 2015; Bosmann et al. 2013; Chen et al. 2014; Chong et al. 2012; Hirose et al. 2014; Huang et al. 2011; Kutcher et al. 2012; Saffarzadeh et al. 2012; Ward and Grailer 2014; Zhang et al. 2013, 2015; Zhao et al. 2014).
If toxic histone levels in plasma are significantly elevated in so many diverse clinical disorders, can this cationic peptide be considered: a novel “alarmin” virulence factor? Therefore, it may effectively be neutralized either by non-anticoagulant heparin (Wildhagen et al. 2014), activated protein C (a proteinase) or antibodies to histone (Xu et al. 2009).
However, since in clinical trials, activated protein C had failed to show effective protection against the aftermath of sepsis and was removed from use, maybe there are other reasons to explain their failure to affect the course of sepsis.
In reality, although non-anticoagulant heparins may prove promising “magic bullets”, their efficacy may unfortunately be still quite limited since treatment of sepsis patients may start several hours–days after admission to the ICU and too late after the “horse had already left the stable”. At later time points, heparins’ action might be ineffective, since the deleterious effects of the immune cytokines storms and coagulation cascades may have already been unleashed. Therefore, a search for novel very early biomarkers might greatly improve early diagnosis and proper treatment may probably be by combinations between antibiotics and heparin (Reinhart et al. 2012; Shukla et al. 2014).
Since sepsis, septic shock, disseminated intravascular coagulopathy (DIC), adult respiratory distress syndrome ARDS and acute lung injury (ALI) as well as additional post-infectious and traumatic sequelae are all regarded as distinct multi-factorial episodes, it may clearly explain the futile attempts over so many years, to prevent mortality by the exclusive administration of only a single antagonist at a time. This definitely calls for the urgent development and testing of appropriate cocktails of inhibitors (Ginsburg 1999) to replace the ineffective single antagonists. After all, today the treatment of AIDS and tuberculosis is successfully controlled by cocktails of drugs.
Conclusions
If one concurs with the assumption that circulating histones from PMNs nets are indeed the major virulence factors in sepsis, then histone inhibitors such as activated protein C, heparin and anti-histone antibodies might prove as magic bullets. However, the main failure of these agent in practice is most probably the result of their late administration when all the cytokines and coagulation cascades had already been unleashed. Since sepsis septic shocks are distinct multi-factorial synergistic episodes, only appropriate early markers may allow early treatment by cocktails of antagonists yet to be established and to discontinue planning new trials to test again only single antagonists already proven to be totally ineffective.
It is surprising therefore that the recent article “Developing a new definition and assessing new clinical criteria for septic shock” (Shankar-Hari et al. 2016) did not include any comments about histone, heparins and their possible involvement in sepsis as published in scores of articles since 2009.
References
Alhamdi Y, Toh CH (2016) The role of extracellular histones in haematological disorders. Br J Haematol 173:805–811. doi:10.1111/bjh.14077
Biezunski N, Shafrir E, De Vries A, Katchalski E (1955) The action of poly-lysine on the conversion of fibrinogen into fibrin by coagulase thrombin. Biochem J 59:55–58
Birmpas C, Joshi A, Barabutis N, Thangjam G, Gregory B, Catravas J (2015) Combination treatment with histone deacetylase 3 and 6 selective inhibitors attenuates lipopolysaccharide-induced acute lung injury (ALI) in mice. FASEB J 29(411):414
Bosmann M et al (2013) Extracellular histones are essential effectors of C5aR- and C5L2-mediated tissue damage and inflammation in acute lung injury. FASEB J Off Publ Fed Am Soc Exp Biol 27:5010–5021. doi:10.1096/fj.13-236380
Chaput C, Zychlinsky A (2009) Sepsis: the dark side of histones. Nat Med 15:1245–1246. doi:10.1038/nm1109-1245
Chen R, Kang R, Fan XG, Tang D (2014) Release and activity of histone in diseases. Cell Death Dis 5:e1370. doi:10.1038/cddis.2014.337
Chong W et al (2012) Anti-inflammatory properties of histone deacetylase inhibitors: a mechanistic study. J Trauma Acute Care Surg 72:347–353. doi:10.1097/TA.0b013e318243d8b2 (discussion 353–344)
De Vries A, Feldman JD, Stein O, Stein Y, Katchalski E (1953) Effects of intravenously administered poly-d l-lysine in rats. In: proceedings of the society for experimental biology and medicine society for experimental biology and medicine, vol 82, pp 237–240
De Vries A, Katchalski E, Stein O (1956) The effect of polyamino acids on the blood vessels of the rat. Archives internationales de pharmacodynamie et de therapie 107:243–253
Ginsburg I (1999) Multi-drug strategies are necessary to inhibit the synergistic mechanism causing tissue damage and organ failure in post infectious sequelae. Inflammopharmacology 7:207–217. doi:10.1007/s10787-999-0004-1
Ginsburg I, Kohen R (1995) Cell damage in inflammatory and infectious sites might involve a coordinated “cross-talk” among oxidants, microbial haemolysins and ampiphiles, cationic proteins, phospholipases, fatty acids, proteinases and cytokines (an overview). Free Radic Res 22:489–517
Ginsburg I, de Vries A, Katchalski E (1952) The action of some water-soluble poly-agr-amino acids on fibrinolysis. Science 116:15–16. doi:10.1126/science.116.3001.15
Ginsburg I, Gibbs DF, Schuger L, Johnson KJ, Ryan US, Ward PA, Varani J (1989) Vascular endothelial cell killing by combinations of membrane-active agents and hydrogen peroxide. Free Radic Biol Med 7:369–376
Ginsburg I, Misgav R, Pinson A, Varani J, Ward PA, Kohen R (1992) Synergism among oxidants, proteinases, phospholipases, microbial hemolysins, cationic proteins, and cytokines. Inflammation 16:519–538
Ginsburg I, Mitra RS, Gibbs DF, Varani J, Kohen R (1993) Killing of endothelial cells and release of arachidonic acid. Synergistic effects among hydrogen peroxide, membrane-damaging agents, cationic substances, and proteinases and their modulation by inhibitors. Inflammation 17:295–319
Hirose T et al (2014) Presence of neutrophil extracellular traps and citrullinated histone H3 in the bloodstream of critically ill patients. PLoS One 9:e111755. doi:10.1371/journal.pone.0111755
Huang H et al (2011) Endogenous histones function as alarmins in sterile inflammatory liver injury through Toll-like receptor 9 in mice. Hepatology 54:999–1008. doi:10.1002/hep.24501
Kutcher ME, Xu J, Vilardi RF, Ho C, Esmon CT, Cohen MJ (2012) Extracellular histone release in response to traumatic injury: implications for a compensatory role of activated protein C. Journal Trauma Acute Care Surg 73:1389–1394. doi:10.1097/TA.0b013e318270d595
Reinhart K, Bauer M, Riedemann NC, Hartog CS (2012) New approaches to sepsis: molecular diagnostics and biomarkers. Clin Microbiol Rev 25:609–634. doi:10.1128/CMR.00016-12
Saffarzadeh M et al (2012) Neutrophil extracellular traps directly induce epithelial and endothelial cell death: a predominant role of histones. PloS One 7:e32366. doi:10.1371/journal.pone.0032366
Shankar-Hari M et al (2016) Developing a new definition and assessing new clinical criteria for septic shock: for the third international consensus definitions for sepsis and septic shock (sepsis-3). Jama 315:775–787. doi:10.1001/jama.2016.0289
Shukla P, Rao GM, Pandey G, Sharma S, Mittapelly N, Shegokar R, Mishra PR (2014) Therapeutic interventions in sepsis: current and anticipated pharmacological agents. Br J Pharmacol 171:5011–5031. doi:10.1111/bph.12829
Ward PA, Grailer JJ (2014) Acute lung injury and the role of histones. Transl Respir Med 2:1. doi:10.1186/2213-0802-2-1
Wildhagen KC et al (2014) Nonanticoagulant heparin prevents histone-mediated cytotoxicity in vitro and improves survival in sepsis. Blood 123:1098–1101. doi:10.1182/blood-2013-07-514984
Xu J et al (2009) Extracellular histones are major mediators of death in sepsis. Nat Med 15:1318–1321. doi:10.1038/nm.2053
Zhang H, Villar J, Slutsky AS (2013) Circulating histones: a novel target in acute respiratory distress syndrome? Am J Respir Crit Care Med 187:118–120. doi:10.1164/rccm.201211-2025ED
Zhang Y et al (2015) Extracellular histones play an inflammatory role in acid aspiration-induced acute respiratory distress syndrome. Anesthesiology 122:127–139. doi:10.1097/ALN.0000000000000429
Zhao T et al (2014) Histone deacetylase inhibitor treatment attenuates coagulation imbalance in a lethal murine model of sepsis. Surgery 156:214–220. doi:10.1016/j.surg.2014.04.022
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Ginsburg, I., Koren, E., Varani, J. et al. Nuclear histones: major virulence factors or just additional early sepsis markers? A comment. Inflammopharmacol 24, 287–289 (2016). https://doi.org/10.1007/s10787-016-0279-y
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10787-016-0279-y