Pathological consequenses of systemic oxidative stress and dyslipidemia in impaired glucose tolerance and diabetes mellitus

Atherosclerosis is a chronic inflammatory disease with increased stress in response to lipid retention in the vessel wall. Diabetes mellitus type 2 is associated with excessive cardiovascular morbidity and mortality. Since atherogenesis already starts before diabetes is diagnosed, we investigated the oxidative stress in the circulation and its associations with dyslipidemia in impaired glucose tolerance (IGT) and diabetes mellitus type 2. Starting from data of a recent study including 125 IGT subjects, 75 patients with newly diagnosed diabetes mellitus type 2, and 403 subjects with normal glucose tolerance (NGT) the pathological consequences of oxidative and metabolic changes in IGT and diabetes mellitus type 2 will be reviewed. The elevated circulating levels of oxidized low-density lipoprotein (oxLDL) in IGT and diabetes mellitus type 2 subjects were not or only weakly related to the oxidative/antioxidative balance in the blood that was characterized by phagocyte oxidant production, serum paraoxonase activity, total antioxidant capacity, and urate-to-allantoin ratio. The close association between oxLDL levels and plasma LDL cholesterol and triglycerides, respectively, favours the hypothesis that dyslipidemia particularly promotes the oxidation of the modified lipoprotein into circulation.