FUNCTIONAL-ACTIVITY OF PLASMA FIBRONECTIN IN PATIENTS WITH DIABETES-MELLITUS

Decreased wound healing and increased infection are major problems in patients with diabetes mellitus. Fibronectin plays a fundamental role in wound healing and acts as an opsonin for the phagocytosis of foreig n antigens. The aim of this study was to ascertain the functional acti vity of plasma fibronectin from patients with diabetes mellitus. Initi ally, a modified Boyden chamber technique was used to measure cell mig ration on fibronectin purified from patient's plasma and an enzyme-lin ked immunosorbent assay was used to measure the binding of gelatin. A sandwich assay was developed that enabled the capture of fibronectin d irectly from patient's plasma without prior purification. With the use of a 96-well format, the binding of two different monoclonal antibodi es could be compared simultaneously with the binding of gelatin and ce ll adhesion. In this way, differences in the function of particular do mains of fibronectin from diabetic patients and control subjects could be measured. Results showed no difference between fibronectin from di abetic patients and control subjects with respect to the monoclonal an tibodies binding in 1) the cell adhesion domain and 2) the heparin-bin ding domain. Furthermore, no detectable differences were noted with re spect to cell adhesion, cell migration, or gelatin binding. These resu lts suggest that diabetic patients receiving insulin treatment show no modulation of plasma fibronectin function, despite raised levels of c irculating glucose.