OXIDATIVE STRESS AT ONSET AND IN EARLY STAGES OF TYPE-1 DIABETES IN CHILDREN AND ADOLESCENTS

OBJECTIVE - In diabetes, the persistence of hyperglycemia has been rep orted to cause increased production of oxygen free radicals through gl ucose autooxidation and nonenzymatic glycation. The aim of this study was to determine whether oxidative cellular damage occurs at the clini cal onset of diabetes and in later stages of the disease in young pati ents. RESEARCH DESIGN AND METHODS - Indicative parameters of lipoperox idation, protein oxidation, and changes in the status of antioxidant d efense systems were evaluated in single blood samples from 54 diabetic children, adolescents, and young adults and 60 healthy age- and sex-m atched control subjects. RESULTS - Malondialdehyde and protein carbony l group levels in plasma were progressively higher in diabetic childre n and adolescents than in control subjects (P < 0.0001). The highest e rythrocyte superoxide dismutase (SOD) activity was found in diabetic c hildren at onset of clinical diabetes. In diabetic adolescents, SOD wa s also significantly higher (P < 0.0001) than in control subjects. Ery throcyte glutathione peroxidase was significantly lower in diabetic ch ildren and adolescents compared with control subjects (P < 0.002), A s ignificant decline in blood glutathione content at the recent onset of diabetes was found (P < 0.0001), Furthermore, our results demonstrate d progressive glutathione depletion during diabetes evolution. The pla sma alpha-tocopherol/total lipids ratio and beta-carotene levels durin g diabetes development (P < 0.001) were lowCONCLUSIONS - This cross-se ctional study in young diabetic patients showed that systemic oxidativ e stress is present upon early onset of type 1 diabetes and is increas ed by early adulthood. Decreased antioxidant defenses may increase the susceptibility of diabetic patients to oxidative injury. Appropriate support for enhancing antioxidant supply in these young diabetic patie nts may help prevent clinical complications during the course of the d isease.