Trimetazidine normalizes postischemic function of hypertrophied rat hearts

The fraction of glucose passing through glycolysis that is oxidized is low in hypertrophied hearts, a pattern of glucose use associated with poor postischemic contractile function. We tested the hypothesis that trimetazidine, a partial 3-ketoacyl coenzyme A thiolase inhibitor, would stimulate glucose oxidation and, thereby, improve fractional glucose oxidation and postischemic function of hypertrophied hearts. Function, glycolysis, and oxidation of glucose, lactate, and palmitate were measured before and after global no- flow ischemia in isolated working hearts from sham-operated (control) and aortic-constricted ( hypertrophied) male Sprague- Dawley rats in the presence or absence of 1 mu M trimetazidine. Heart function was significantly improved by trimetazidine after ischemia, but only in hypertrophied hearts, with function improving to values in untreated control hearts. This effect occurred in association with relatively minor changes in oxidative metabolism. However, trimetazidine reduced glycolysis by similar to 30% but did so only in hypertrophied hearts, an unexpected novel action of this agent that resulted in a larger fractional oxidation of glucose, effectively normalizing it in hypertrophied hearts. Thus, trimetazidine normalizes postischemic function and fractional glucose oxidation in hypertrophied hearts, mainly by reducing glycolysis. These data extend the potential usefulness of trimetazidine and provide support for its use as a means to improve postischemic function of pressure overload hypertrophied hearts.