Erythrocyte and plasma cholesterol exchange in sickle cell anemia

The effects of sickling on cholesterol exchange between red cell membranes and serum lipoproteins were studied by following the movement of tritiated cholesterol incorporated into erythrocytes. The initial rate of this exchange was greater in sickled cells than in normal cells. One quarter of the cholesterol in the sickled cells is quickly exchanged with plasma lipoproteins. After 15 minutes, the rate becomes identical for these two types of cells, reaching similar equilibrium at end. The sickling of red cells would explain the observed differences, although conditions of hypoxia and the saturation of the incubation medium with oxygen tend respectively to accentuate and to cancel this phenomenon.