[Glycosylation and lipid peroxidation in skin and in plasma in diabetic patients]

Glycation and free radical reactions may play a role in complications of diabetes. Vascular complications, as a consequence of atherosclerosis, are the main causes of morbidity and mortality in diabetes. The aim of this work was to study glycation and lipid peroxidation (LPO) in plasma and skin of type 2 diabetic patients. The levels of advanced glycation endproducts (AGEs) in skin collagens are considered as the sum of accumulated glycation over time. We studied 20 subjects with type 2 diabetes and 20 controls. Glycated proteins were quantified in skin and plasma by affinity chromatography in aminophenyl boronate gels. AGEs were determined on skin collagen by fluorimetry. LPO was evaluated by fluorimetry measuring TBARS in the skin and plasma. Skin collagen-linked fluorescence (CLF) was higher in diabetics (p < 0.01). CLF in diabetics with retinopathy was higher than that of diabetics without retinopathy (p < 0.02). There was a positive correlation between duration of diabetes and skin CLF (p < 0.01). TBARS were higher in skin (p < 0.01) and plasma (p < 0.001) of diabetic patients. We did not find any correlation between CLF and TBARS. This is not surprising taking into account the complexity and multifactorial aspects involved in LPO, while in glycation the main determinant factor is hyperglycemia.