Involvement of fibrinogen specific binding in erythrocyte aggregation.

Increased fibrinogen concentration and erythrocyte aggregation are significant risk factors during various cardiovascular diseases and cerebrovascular disorders. Currently, fibrinogen-induced erythrocyte aggregation is thought to be caused by a non-specific binding mechanism. However, the published data on changes in erythrocyte aggregation during hypertension point to the possible existence of other mechanism(s). Therefore, we tested the hypothesis that specific binding of fibrinogen is involved in erythrocyte aggregation. It was found that Oregon Green 488-labeled human fibrinogen specifically binds rat erythrocyte membranes with a Kd of 1.3 microM. Further experiments showed that the peptide Arg-Gly-Asp-Ser blocked both fibrinogen-induced aggregation of intact erythrocytes and specific binding of fibrinogen to the erythrocyte membranes. These results suggest that in addition to non-specific binding, a specific binding mechanism is also involved in fibrinogen-induced erythrocyte aggregation.