Study of vitamin E net mass transfer between alpha-tocopherol-enriched HDLand erythrocytes: Application to asymptomatic hypercholesterolemic men

We previously showed that hypercholesterolemic asymptomatic men had lower e rythrocyte vitamin E content, despite normal plasma concentrations compared to normocholesterolemic men. We hypothesized that the reduced erythrocyte vitamin E concentration could be due to an impairment of transfer of vitami n E from plasma lipoproteins. We first developed a model for testing the ab ility of erythrocytes to accept vitamin E from high-density lipoproteins (H DL) pre-enriched in vitamin E, which allows to measure a net mass transfer of vitamin E from HDL to erythrocytes. Vitamin E-enriched HDL were obtained in controlled conditions of concentration and incubation time with a good reproducibility (CV less than or equal to 10%). The kinetic study of the ne t mass transfer of vitamin E to erythrocytes of healthy volunteers shows sm all inter- and intraindividual variations. The application of this model to erythrocytes of hyper- and normocholesterolemic men demonstrates that the reduced erythrocyte vitamin E content observed in hypercholesterolemic men was not due to a reduced ability of these cells to accept vitamin E from HD L. It might rather be due to an impairment of lipoproteins in the delivery of vitamin E to tissues, or to an oxidative stress which consumes antioxida nts. (C) 2000 Elsevier Science Inc.