Increased plasma levels of Fibronectin (Fn),a well known adesive glycoprotein synthesized in vessel endothelial cells, have been reported in diabetes mellitus (DM). Previously, we provided evidence that in type II DM an elevated storage of Fn is present in endothelial cells. We here report that in diabetic subjects an abnormal synthesis of Fn in endothelial cells could also occur. To verify this hypothesis, in 15 patients affected by type II DM, age ranging 36-59, of both sex, without overt clinical vascular complications and in glycometabolic compensation (Hb Alc 8.9 ± 1.5) we evaluated before and after venostasis repeated at several times 30, 60, 90,180 and 210 min the Fn plasma levels. Five healthy volunteers, age and sex comparaf-h ble, were utilized as normal controls. The venostasis were performed at forearm pressure of 10 mmHg over diastolic x 20 min and blood samples were collected from the same vein at the intervals above indicated. Plasma Fn was evaluated by ELISA immuno-enzymatic tecnique using a commercial kit (Biochemia, Milan). The diabetic patients showed after the first venostasis a significant (p<0.001) increase of Fn (317 ± 103μg/ml) versus the baseline values (225±79 μg/ml)while normal controls did not (before 103 ± 37, after 139±61). Such an increase was also seen in EM after the second venostasis ( 298 ±91 μg/ml, vs 128±58 in controls), whereas at third venostasis plasma Fn levels retoumed to the values comparable to the basal ones both in diabetics (245 ±. 88 μg/ml) and in controls (93±41 μg/ml). After 90 min pause by performing the fourth venostasis we observed in diabetics a further increase pf Fn (298±131μg/ml) which reached:again the values noted after the first. No change, on the contrary,was found in the normal group (95±21). In the last venostasis,carried out 30min from the fourth, the plasna Fn lasted significantly (p<0.001.) increased in diabetics (281±107 μg/ml) respect to normal controls (102±19 μg/ml).Our data, therefore, would suggest that in vascular endothelium cf type II DM an increased synthesis of Fn occurs as well.
Expression of glycogen synthase and phosphofructokinase in muscle from Type 1 (insulin-dependent) diabetic patients before and after intensive insulin treatment