Platelet hypoaggregability in hereditary hypertriglyceridemic rats: relation to plasma triglycerides.

To define better the relationships between lipid metabolism disturbances and platelet aggregation we have examined these parameters in hereditary hypertriglyceridemic and control Lewis rats. Hereditary hypertriglyceridemic rats are hypertensive and have high plasma triglycerides but not elevated plasma total cholesterol. In the present study, we have demonstrated that platelets from hereditary hypertriglyceridemic rats have lowered initial rate and maximal aggregation after stimulation with thrombin or ADP in comparison with controls.

Platelet aggregation and in vivo shear forces.

Haemodynamic shear forces have been reported to exert direct and indirect effects on platelet reactivity. In vitro, they activate platelets leading to spontaneous or facilitated aggregation. In vivo, they stimulate the production of endothelium-derived anti-aggregatory agents.

Acute membrane effects of trimetazidine in human platelets.

The mechanisms by which trimetazidine (1-[2,3,4-trimethoxybenzyl]-piperazine) exerts its cytoprotective action have not been identified. This study was designed to investigate in human platelets and erythrocyte ghosts a possible perturbation of membrane dynamics by trimetazidine. Its effects on the steady-state anisotropies of two fluorescent probes, trimethylamino-diphenyl-hexatriene (TMA-DPH) and diphenylhexatriene (DPH) were compared.

Plasma lipids and platelet membrane fluidity in essential hypertension.

Essential hypertension is often associated with high levels of plasma cholesterol or triglycerides. The relationships between plasma lipids and platelet lipids, membrane fluidity and functions in untreated hypertensive patients were investigated by measuring the fluorescence anisotropies of two fluorescent dyes (DPH and its cationic derivative, TMA-DPH, with different subcellular localization), cytosolic Ca2+ and pH, cyclic AMP content and aggregation to ADP and collagen. Hypercholesterolemia was found to be accompanied by a rise in platelet cholesterol content without changes in TMA-DPH or DPH anisotropies whereas hypertriglyceridemia was associated with a decreased cholesterol to phospholipid molar ratio, a decreased DPH anisotropy and a tendency of the cytosol to alkalinize.

Biochemical and functional alterations associated with hypercholesterolemia in platelets from hypertensive patients.

Hypercholesterolemia and hypertension are two of the major risk factors associated with increased atherosclerotic vascular disease. An abnormal platelet function is one of the mechanisms proposed to participate in atherogenesis. This study was undertaken to find out whether hypercholesterolemia in hypertensive patients can change platelet lipid composition and reactivity.