Influence of sialic acid on erythrocyte aggregation in hypercholesterolemia

The respective role of adhesive forces induced by fibrinogen and repulsive forces induced by erythrocyte sialic acid content on erythrocyte aggregation, was investigated in hypercholesterolemic and control subjects. Aggregation index (AI) and disaggregation shear rate threshold (gamma t) were determined in the presence of either autologous plasma or dextran. Compared with controls, fibrinogen (p < 0.001) and aggregation parameters (AI p < 0.01; gamma t p < 0.01) were higher in hypercholesterolemics while erythrocyte sialic acid content (p < 0.001) was lower; in addition total serum sialic acid was increased (p < 0.01). The aggregation properties of erythrocytes, independent of plasma environment using dextran as a bridging macromolecule, showed an enhanced disaggregation shear rate threshold and an inverse relationship with erythrocyte 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.