Superoxide- and nitric oxide-derived species mediate endothelial dysfunction, endothelial glycocalyx disruption, and enhanced neutrophil adhesion in the post-ischemic guinea-pig heart.
The study was aimed at testing the hypothesis that a toxic product of the reaction between superoxide (O(2)(-)) and nitric oxide (NO) mediates, not only endothelial dysfunction, but also endothelium-glycocalyx disruption, and increased neutrophil (PMN) accumulation in the heart subjected to ischemia/reperfusion (IR) injury. Accordingly, we studied if scavengers of either O(2)(-) or NO, or a compound that was reported to attenuate cardiac production of peroxynitrite, would prevent endothelial injury and subsequent PNM adhesion in IR heart. Langendorff-perfused guinea-pig hearts were subjected to 30 min ischemia/35 min reperfusion, and infusion of PMN between 15 and 25 min of the reperfusion. Coronary flow responses to acetylcholine (ACh) and sodium nitroprusside (SNP) were used as measures of endothelium-dependent and -independent vascular function, respectively. PMN adhesion and endothelium glycocalyx ultrastructure were assessed in histological preparations. IR impaired the ACh, but not SNP, response by approximately 60%, caused endothelium-glycocalyx disruption, and approximately nine-fold increase in PMN adhesion. These alterations were prevented by superoxide dismutase (150 U/ml), NO synthase inhibitor, L-NAME (10 microM), NO scavenger, oxyhemoglobin (25 microM), and NO donor, SNAP (1 microM), and were not affected by catalase (600 u/ml). The glycocalyx-protective effect of these interventions preceded their effect on PMN adhesion. The data imply that PMN adhesion in IR guinea-pig heart is a process secondary to functional and/or structural changes in coronary endothelium, and that a toxic product of the reaction between superoxide and NO mediates these endothelial changes.
Department of Clinical Physiology, Medical Center of Postgraduate Education, Marymoncka 99, 01-813 Warsaw, Poland.
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M
Kurzelewski
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Czarnowska
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Beresewicz
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D002448:Cell Adhesion; D003326:Coronary Circulation; D004730:Endothelium, Vascular / Q000502:physiology*; D019276:Glycocalyx / Q000378:metabolism*; D006168:Guinea Pigs; D017202:Myocardial Ischemia / Q000503:physiopathology*; D009504:Neutrophils / Q000502:physiology*; D009569:Nitric Oxide / Q000378:metabolism*; D009599:Nitroprusside / Q000494:pharmacology; D013481:Superoxides / Q000378:metabolism*
D013481:Superoxides; D009599:Nitroprusside; D009569:Nitric Oxide; D000109:Acetylcholine