The Influence of Oxidatively Modified Low Density Lipoprotein on Parameters of Energy Metabolism and Contractile Function of Arterial Smooth Muscle

Recently published results provide evidence of the importance of oxidatively modified LDL in the development of atherosclerosis. Several typical characteristics of this disease can be ascribed to the effects of oxidized LDL on the different cells involved in lesion formation. In various cell culture systems oxidized LDL was found to be cytotoxic. Therefore we were interested in its influence on parameters of energy metabolism such as glycogen and ATP content as determined for aortic segments in vitro. The results show that oxidized LDL leads to sharp decreases in both parameters, indicating an activation of cellular energy metabolism. Findings obtained from contraction experiments in which oxidized LDL shows a contractionenhancing effect on arterial segments suggest that the oxidized lipoprotein facilitates cellular Ca2+ liberation. This seems to be a common signal leading to its effects on energy metabolism and contraction and could also explain its cytotoxicity if cells are exposed to it for longer periods.