Coagulation pathways and diabetic retinopathy: Abnormal modulation in a selected group of insulin dependent diabetic patients

Abstract

Aims - To investigate whether diabetic retinopathy (DR), already associated with microvascular alterations, ischaemia, and endothelial dysfunction, was also characterised by abnormal modulation of coagulation pathways. Methods - Plasma samples, collected from 67 type 1 diabetics comparable for age, duration of disease (DD), and metabolic control (MC), were processed for prothrombin degradation products (F1+2) and factor VII coagulant activity (FVII:c). 50 normal subjects served as a control group. The ETDRS-Airlie House Classification of DR was used. Results - A significant correlation between FVII:c and F1+2 plasma concentrations was observed (p < 0.05). FVII:c (p < 0.005) and F1+2 (p < 0.0001) levels were higher in diabetics than in controls, especially in patients with proliferative DR (FVII:c p < 0.0001; F1+2 p < 0.005). However, cases without retinal lesions and healthy subjects did not differ significantly (FVII:c and F1+2 p > 0.05). Conclusions - These findings pointed out the presence of a hypercoagulable state associated with endothelial dysfunction in patients with insulin dependent diabetes mellitus (IDDM), demonstrated both by increased FVII:c and F1+2 plasma levels. Moreover, the observation of different DR related degrees of procoagulant activity, despite comparable DD and MC, strengthens the hypothesis of multiple risk factors in the pathogenesis of DR.