Role of Oxidative Stress and Inflammatory Factors in Diabetic Kidney Disease

Diabetic nephropathy (DN) is a serious complication of diabetes mellitus, and its prevalence has been increasing in developed countries. Diabetic nephropathy has become the most common single cause of end-stage renal disease worldwide. Oxidative stress and inflammation factors are hypothesized to play a role in the development of late diabetes complications. Chronic hyperglycemia increases oxidative stress, significantly modifies the structure and function of proteins and lipids, and induces glycoxidation and peroxidation. Therefore, hyperglycemia causes auto-oxidation of glucose, glycation of proteins, and activation of polyol mechanism. Overproduction of intracellular reactive oxygen species contributes to several microvascular and macrovascular complications of DN. On the other hand, reactive oxygen species modulates signaling cascade of immune factors. An increase in reactive oxygen species can increase the production of inflammatory cytokines, and likewise, an increase in inflammatory cytokines can stimulate the production of free radicals. Some studies have shown that kidney inflammation is serious in promoting the development and progression of DN. Inflammatory factors which are activated by the metabolic, biochemical, and hemodynamic derangements are known to exist in the diabetic kidney. This review discusses facts for oxidative stress and inflammatory factors in DN and encompasses the role of immune and inflammatory cells, inflammatory cytokines, and stress oxidative factors.