Novel small molecule inhibitor of C1s exerts cardioprotective effects in ischemia-reperfusion injury in rabbits.
Myocardial ischemia-reperfusion injury can be related to complement activation with generation of chemotactic agents, adhesion molecule expression, release of cytokines and oxygen-derived free radicals, and subsequent neutrophil accumulation. In the present study the cardioprotective effects of a novel highly selective small molecule C1s inhibitor (C1s-INH-248, Knoll) were examined in a rabbit model of myocardial ischemia (I) and reperfusion (R; i.e., 60 min I + 180 min R). In in vitro tests (enzyme activity and SRBC lysis) C1s-INH-248 demonstrated profound inhibitory potency. In vivo C1s-INH-248 (1 mg/kg body weight) administered 5 min before reperfusion significantly attenuated myocardial injury (31.9 +/- 2.5 vs 8.9 +/- 1.6% necrosis/area at risk; p < 0.01). The cardioprotective effect was dose dependent. The reduction of myocardial injury was also observed as diminished plasma creatine kinase activity in C1s-INH-248-treated animals (70.7 +/- 6.8 vs 45.1 +/- 3.9 U/g protein after 3 h of reperfusion, p < 0.05). Further, cardiac myeloperoxidase activity (i.e., a marker of PMN accumulation) in the ischemic and necrotic area was significantly reduced following C1s-INH-248 treatment (1.31 +/- 0.23 vs 0.4 +/- 0.05 U/100 mg tissue in necrotic area, p < 0.01). Thus, blocking the classical complement pathway with a highly specific and potent synthetic inhibitor of the activated C1 complex appears to be an effective mean to preserve ischemic myocardium from injury following reperfusion.
Buerke
M
M
Second Department of Medicine, Johannes Gutenberg University, Mainz, Germany. buerke@mail.uni-mainz.de
Schwertz
H
H
Seitz
W
W
Meyer
J
J
Darius
H
H
D000818:Animals; D003167:Complement Activation / Q000187:drug effects; D003174:Complement C1 Inactivator Proteins / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000166:cytology; D006439:Hemodynamics / Q000187:drug effects; D006461:Hemolysis / Q000187:drug effects; D007958:Leukocyte Count; D008297:Male; D017202:Myocardial Ischemia / Q000188:drug therapy*; D015428:Myocardial Reperfusion Injury / Q000517:prevention & control*; D009504:Neutrophils / Q000502:physiology; D011817:Rabbits; D013481:Superoxides / Q000378:metabolism
D003174:Complement C1 Inactivator Proteins; D013481:Superoxides