DISTRIBUTION OF ERYTHROCYTE-MEMBRANE CHOLESTEROL IN HUMAN ESSENTIAL-HYPERTENSION

Objective: To determine whether the cholesterol distribution is impair ed in erythrocyte membranes of normo- and hypercholesterolaemic patien ts with untreated essential hypertension. Design: Observational case-c ontrol study. Methods: Erythrocytes were prepared from venous blood sa mples obtained from normotensive subjects and hypertensive patients. T he membrane cholesterol distribution was measured by cholesterol oxida tion to cholestenone after continuous cholesterol oxidase treatment. T he membrane cholesterol content was determined. The ability of cells t o be labelled with [H-3]-cholesterol was also tested. Results: The cho lesterol distribution was asymmetric in erythrocyte membranes of the c ontrol subjects and hypertensive patients. The oxidation rate was fast er in normotensive subjects, and no differences were found between nor mo- and hypercholesterolaemic hypertensive patients. Total cholesterol mass was lower in erythrocyte membranes of hypertensive patients, as indicated by a higher incorporation of radioactive cholesterol. Conclu sion: These data suggest that the membrane cholesterol distribution is impaired in patients with untreated essential hypertension, and suppo rt the presence of cholesterol-rich domains in the erythrocyte membran e inner monolayer.