The effect of hypercholesterolaemia on the lipid composition and ability of human platelets to accumulate cyclic AMP.

Washed human platelets from seventeen hypercholesterolaemic subjects were compared to those from seventeen age and sex matched controls with respect to lipid composition and ability to accumulate cyclic AMP. No significant difference in platelet lipid composition was found in terms of total cholesterol, phospholipid or the ratio of cholesterol to phospholipid. There was no significant different in basal levels of platelet cyclic AMP between the two groups. Platelets from hypercholesterolaemic subjects showed an impaired ability to accumulate cyclic AMP compared with controls when challenged with prostaglandins (PG) I2, D2 and E1. The platelet inhibitory actions of PGI2, PGD2 and PGE1, which are mediated by cyclic AMP are thought to be important mechanisms for the control of platelet-platelet and platelet-vessel wall interaction. Thus, an impaired response to these three prostaglandins may be relevant to our understanding of the role played by the platelet in mediating vessel wall pathology caused by hypercholesterolaemia.