Increased plasma fibronectin concentration in diabetic patients with microalbuminuria.

Abstract

Raised levels of plasma fibronectin (PF), an alpha 2-glycoprotein produced by vascular endothelia, have been previously described in diabetic patients with retinopathy and overt nephropathy. The aim of this study was to investigate whether the presence of microalbuminuria is associated with increased PF concentrations. Twenty Albustix-negative diabetic outpatients with microalbuminuria [median albumin excretion rate (AER): 30.2 micrograms/min; range 12.1-194 micrograms/min] were compared with 58 sex- and age-matched patients without microalbuminuria (median AER 3.1 micrograms/min; range 0.8-12 micrograms/min) and 34 control subjects (median AER 2.8 micrograms/min; range 0.8-12.1 micrograms/min). Mean PF was significantly higher in the group with microalbuminuria (406.7 +/- 85.5 micrograms/ml) than in the group without it (325.3 +/- 76.5 micrograms/ml or in control subjects (334.5 +/- 76 micrograms/ml; P less than .05). PF increase associated with microalbuminuria was independent of the presence of retinopathy. Furthermore, in the whole group of diabetic patients, PF was significantly correlated with AER (r = .33; P = .003). Such correlation also remained significant (P = .0002) after covariance analysis by a stepwise discriminant procedure taking into account age, duration of disease, sex, blood pressure, body weight, therapy, and HbA1. In conclusion, PF increase is associated with microalbuminuria independent of the other considered variables; its role as a possible marker for early diabetic nephropathy remains to be fully clarified.