Effects of amphiphiles on erythrocytes, coronary arteries, and perfused hearts

Abstract

Due to their unique structure, lysophosphoglycerides (such as lysophosphatidylcholine, LPC), compounds known to accumulate in ischemic myocardium, form micelles at concentrations exceeding the critical micelle concentration (CMC). In this study, we found that sub-CMC levels of LPC exerted dose-dependent morphological changes on red blood cells and elicited dysrhythmia and contracture while increasing coronary artery resistance in isolated hearts. LPC at supra-CMC concentrations lysed red blood cells, elicited virtually instantaneous contracture in perfused hearts, and constricted isolated coronary arteries. Because bile salts form micelles also, effects of LPC were compared with those induced by selected concentrations of bile salts. At sub-CMC levels, bile salts did not affect red cell morphology appreciably and exerted only negative ino- and chronotropic effects in isolated hearts. However, at supra-CMC concentrations, bile salts lysed red blood cells and caused contracture in the hearts. Thus LPC exerts specific effects at sub-CMC levels independent of nonspecific detergent effects of micelles. These specific effects may contribute to the mechanical and electrical dysfunction associated with myocardial ischemia.