ristocetin and Diabetic-Retinopathy

Plasma coagulation factors were measured in twelve male insulin-dependent diabetics with no retinopathy, ten with background and ten with proliferative retinopathy and ten non-diabetics. Factor VIII pro-coagulant activities (VIII:C), ristocetin cofactor activities and factor VIII-related antigen concentrations (VIIIR:ag) were significantly related to the severity of diabetic retinopathy (P less than 0.025, trend test). The mean ratio of VIII:C/VIIIR:ag was lower in the diabetics with proliferative retinopathy than in the other groups of diabetics (P less than 0.05) or the controls (P less than 0.02). Concentrations of alpha 2 macroglobulin and alpha 1 antitrypsin were highest in diabetics with proliferative retinopathy (0.1 greater than P greater than 0.05, trend test) but mean prothrombin and activated partial thromboplastin times and mean concentrations of alpha 2 antiplasmin, plasminogen activator and antithrombin III were similar in all groups. Concentrations of the platelet-specific protein beta thromboglobulin, though higher in diabetics than controls (P less than 0.005), were not related to retinopathy. The plasma concentrations of coagulation factors did not correlate with creatinine clearance and there were no significant differences between groups in concentrations C-reactive protein; this suggests that the raised concentrations of coagulation factors in diabetics with retinopathy were not a result of associated nephropathy or an 'acute phase protein' response to diabetic tissue damage. Increased coagulation activity in diabetics may contribute to the development of retinopathy.

Topics: Adult; alpha 1-Antitrypsin; alpha-Macroglobulins; Antigens; beta-Thromboglobulin; Blood Coagulation Factors; C-Reactive Protein; Diabetic Retinopathy; Factor VIII; Glycated Hemoglobin; Humans; Male; Middle Aged; Ristocetin; von Willebrand Factor

Topics: Adult; Aged; Blood Coagulation Factors; Diabetes Mellitus; Diabetic Retinopathy; Humans; Middle Aged; Platelet Aggregation; Ristocetin; von Willebrand Factor

Topics: Adult; Antigens; Arteriosclerosis; Cholesterol; Diabetes Complications; Diabetes Mellitus; Diabetic Retinopathy; Factor VIII; Fibrinogen; Fibrinolysis; Humans; Lipoproteins, HDL; Male; Middle Aged; Ristocetin

In 18 insulin-dependent diabetics (6 without retinopathy, 6 with proliferative retinopathy and 6 with proliferative retinopathy treated by hypophysectomy) matched for age and duration of diabetics, in vitro haemostasis was studied using ADP induced platelet aggregation, ristocetin induced platelet aggregation which allows von Willebrand factor (VIII VWF) assay, and determination of antihemophilic factor procoagulant activity (VII AHF). Using gel filtration-isolated platelets, the ADP induced hyperaggregation previously reported in diabetics with severe retinopathy untreated by hypophysectomy appeared to be related to a platelet and not a plasma factor; the normal results of thrombin induced aggregation suggests that the presumed abnormal platelet factor is related to the platelet plasma membrane. High level of plasma VII VWF was observed in diabetics with proliferative retinopathy while the VII AHF level was within normal limits.

Topics: Adenosine Diphosphate; Adolescent; Adult; Blood Coagulation Factors; Diabetic Retinopathy; Factor VIII; Female; Humans; Hypophysectomy; Male; Middle Aged; Platelet Aggregation; Ristocetin; Thrombin; von Willebrand Diseases

Topics: Adenosine Diphosphate; Blood Coagulation Factors; Diabetes Mellitus; Diabetic Retinopathy; Factor VIII; Humans; Hypophysectomy; Platelet Adhesiveness; Platelet Aggregation; Ristocetin