Thrombin increases cardiomyocyte acute cell death after ischemia and reperfusion.
Thrombin exerts multiple actions on cardiomyocytes leading to increased intracellular Na+ and Ca2+ concentrations, and to activation of a Ca2+-independent PLA2, and has been proposed to favor the genesis of arrhythmias and ischemic injury in acute coronary syndromes. However, the influence of thrombin on cardiomyocyte cell death during ischemia-reperfusion has not been studied. A beneficial influence of low thrombin concentrations has been described in other cell types. HL-1 cardiomyocytes were subjected to simulated ischemia (SI) and reperfusion (SR) and cell death was assessed by means of LDH release to the incubation media. Thrombin dose-dependently increased cell death in normoxic cells, in cells subjected to SI, and in cells subjected to SR (by 20+/-8%, 95+/-32% and 35+/-9%, respectively, at 100 U/ml). The effects of thrombin were associated to increased cytosolic Ca2+ overload, mimicked by 100 microM PAR-1 agonist peptide SFLLRNPNDKYEPF, and reversed by the direct thrombin inhibitor lepirudin (IC50=1.3+/-0.2 microg/ml). The presence of thrombin during simulated ischemia-reperfusion increases cardiomyocyte cell death by a mechanism that involves activation of PAR-1 receptors and can be prevented by the direct thrombin inhibitor lepirudin.
Mirabet
Maribel
M
Servicio de Cardiología, Hospital Universitari Vall d'Hebron, Pg. Vall d'Hebron 119-129, 08035 Barcelona, Spain.
Garcia-Dorado
David
D
Ruiz-Meana
Marisol
M
Barrabés
José A
JA
Soler-Soler
Jordi
J
D000818:Animals; D020013:Calcium Signaling / Q000187:drug effects; D016923:Cell Death / Q000187:drug effects; D002478:Cells, Cultured; D004072:Digitonin / Q000494:pharmacology; D006629:Hirudins / Q000494:pharmacology; D045022:Lactate Dehydrogenases / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D017202:Myocardial Ischemia / Q000139:chemically induced / Q000473:pathology*; D015428:Myocardial Reperfusion Injury / Q000139:chemically induced / Q000473:pathology*; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000473:pathology*; D018179:Receptors, Thrombin / Q000819:agonists; D011994:Recombinant Proteins / Q000494:pharmacology; D013917:Thrombin / Q000037:antagonists & inhibitors / Q000494:pharmacology*
D006629:Hirudins; D018179:Receptors, Thrombin; D011994:Recombinant Proteins; D045022:Lactate Dehydrogenases; C071195:D-lactate dehydrogenase; D013917:Thrombin; D004072:Digitonin; C083544:lepirudin