INFLUENCE OF SIALIC-ACID ON ERYTHROCYTE AGGREGATION IN HYPERCHOLESTEROLEMIA

The respective role of adhesive forces induced by fibrinogen and repul sive forces induced by erythrocyte sialic acid content on erythrocyte aggregation, was investigated in hypercholesterolemic and control subj ects. Aggregation index (Al) and disaggregation shear rate threshold ( yt) were determined in the presence of either autologous plasma or dex tran. Compared with controls, fibrinogen (p < 0.001) and aggregation p arameters (Al p < 0.01; gamma t p < 0.01) were higher in hypercholeste rolemics while erythrocyte sialic acid content (p < 0.001) was lower; in addition total serum sialic acid was increased (p < 0.01). The aggr egation properties of erythrocytes, independent of plasma environment using dextran as a bridging macromolecule, showed an enhanced disaggre gation shear rate threshold and an inverse relationship with erythrocy te sialic acid content. We conclude that decreased erythrocyte sialic acid content may intensify the effect of fibrinogen on aggregation and disaggregation of erythrocytes and participate in the development of atherothrombotic complications.