Plasma fibronectin in diabetic retinopathy and macroangiopathy

To establish the relation between plasma fibronectin (PF) and vascular complications of diabetes mellitus, we studied 163 normotensive diabetic outpatients, of whom 53 were treated with insulin (15 type I, 38 type II) and 110 with sulfonylureas, and compared them to 34 control subjects. Diabetic patients were divided, according to their therapy, into four groups: with retinopathy (classified as background or proliferative) detected by fluorescein angiography (m), with macroangiopathy, assessed by clinical criteria (M), with both vessel complications (mM) and without vascular disease (N). PF was not related to glycosylated hemoglobin (HbA1) in each treatment group (r = 0.26; P = 0.051 in the insulin treated patients and r = 0.09; P = 0.356 in the group on oral drugs). PF levels were similar in M groups, either on insulin or sulfonylureas and in controls. Both m and mM subsets of patients were, conversely, characterized by significantly raised mean PF concentrations when compared to N subjects or controls, but proliferative retinopathy was not associated with a significant PF increase compared to background retinopathy. The differences of PF levels among m, mM and N groups remained significant after processing the data by means of stepwise discriminant analysis with age, duration of diabetes, body weight and HbA1 entering the model as covariates. We conclude that diabetic macroangiopathy is not associated with modifications of mean PF levels, which, on the contrary, appear increased only in diabetic patients with retinopathy, regardless of their therapy.