TOTAL PLASMA ANTIOXIDANTS IN FIRST-DEGREE RELATIVES OF PATIENTS WITH INSULIN-DEPENDENT DIABETES

Insulin-dependent diabetes mellitus (IDDM) is a chronic disorder that results from autoimmune destruction of the pancreatic beta-cells. Rece nt evidence suggests that oxidative damage, resulting from both cytoki ne-induced production of toxic free radicals and low antioxidant capac ity of the beta-cell plays a significant role in the pathogenesis of I DDM. Islet cell antibodies (ICA) have been the best validated marker o f risk for the development of IDDM in predisposed individuals, i.e. fi rst-degree relatives of patients with IDDM. We investigated the total plasma antioxidant status (TAS) in both ICA-positive and ICA-negative first-degree relatives of patients with IDDM, to assess the level of o verall protection against oxidative damage. TAS was significantly lowe red in ICA-positive when compared to both ICA-negative and healthy sub jects (p < 0.001), while no significant difference was found in compar ison to recently diagnosed patients with IDDM. TAS values were not sig nificantly influenced by gender, age and smoking habits in all groups, as well as by ICA titers in the group of ICA-positive subjects. Resul ts indicate that prediabetic condition, apart from well-established im munological and metabolic alterations, could be associated with bioche mical changes revealing complex disturbances of the antioxidative defe nce system. Although TAS is a functional rather than specific marker, its measurement is likely to be a valuable tool for understanding the mechanisms of specific beta-cell injury.