Plasma Cofactors of Platelet Function: Correlation with Diabetic Retinopathy and Hemoglobins Ala-c

Abstract

Twenty-nine diabetic patients (8 without and 21 with retinopathy) and 29 matched control subjects were studied for Hb Ala-c and plasma levels of fibrinogen, von Willebrand factor and factor VIII/von Willebrand factor antigen. Hb Ala-c were elevated in all diabetic patients, regardless of retinopathy (P < 0.001); fibrinogen was elevated only in those with retinopathy (P < 0.001); and plasma von Willebrand factor was clearly elevated in those with proliferative retinopathy and minimally, if at all, in those with background or no retinopathy. Plasma from 5 diabetic patients with proliferative retinopathy and 5 control subjects was tested for its ability to enhance the ADP-induced platelet aggregation of normal or von Willebrand platelet-rich plasma; no differences were found. Elevated levels of fibrinogen and von Willebrand factor, (both recognized plasma cofactors of platelet function) are associated with proliferative diabetic retinopathy. A plasma factor that enhances ADP-induced platelet aggregation could not be found in diabetic plasma; increased von Willebrand factor is probably not responsible.