ALTERED PROPERTIES OF THE FIBRIN GEL STRUCTURE IN PATIENTS WITH IDDM

High plasma fibrinogen levels are associated with vascular complicatio ns in the general population. Fibrin, the structural element in a clot , is derived from fibrinogen by activation of thrombin. An abnormal fi brin gel structure has been demonstrated in patients with myocardial i nfarction and in diabetic patients during poor metabolic control. In t he present study the properties of fibrin gel structure were investiga ted in 20 patients with insulin-dependent diabetes mellitus (IDDM): 10 patients without (age: 30 +/- 8; diabetes duration: 7 +/- 6 years), a nd 10 patients (age: 44 +/- 7; diabetes duration: 27 +/- 9 years) with microangiopathy. Fifteen healthy subjects served as controls (age: 40 +/- 8 years). The glycosylated haemoglobin level (HbA(1c)) was elevat ed (p < 0.001) in the patients: 6.5 +/- 1.5 % in diabetic patients wit hout, and 7.1 +/- 1.0 % in diabetic patients with microangiopathy. C-r eactive protein and plasma fibrinogen were similar as compared to heal thy control subjects. The properties of the fibrin gel structure; i.e. the permeability coefficient (Ks) and the fibre mass length ratio (mu ) formed in recalcified plasma on addition of thrombin were investigat ed. Ks was decreased in the diabetic patients, with (6.5 +/- 2.0 cm(2) ; p < 0.01) and without microangiopathy (6.5 +/- 2.7 cm(2), p < 0.05), as compared to healthy subjects (10.0 +/- 3.4 cm(2)), while Ec was no t significantly (p = 0.14) altered. The results indicate a lower fibri n gel porosity in patients with IDDM, despite normal plasma fibrinogen and irrespective of microangiopathy. The abnormal fibrin gel structur e may be due to an increased glycosylation of the fibrin (-ogen) molec ule caused by long-term hyperglycaemia and may be of importance for th e development of angiopathy in diabetic patients.