Programmed Cell Death in Diabetic Nephropathy: A Review of Apoptosis, Autophagy, and Necroptosis

Diabetic nephropathy is a common complication of type I and type II diabetes, in which renal glomeruli are destroyed, resulting in renal damage, proteinuria, and hypertension. Apoptosis, autophagy, and necroptosis are 3 forms of programmed cell death that have been implicated in the pathogenesis of diabetic nephropathy. Apoptosis of podocytes leads to glomerular injury and podocyte depletion, which are associated with proteinuria and glomerular structural damage in diabetic nephropathy. Additionally, epithelial cells in the proximal convoluted tubules also undergo apoptosis in diabetic nephropathy, leading to tubular atrophy, which causes tubular cell depletion and the subsequent formation of atubular glomeruli in association with the loss of renal function. On the other hand, insufficiency of autophagy has been correlated with the pathogenesis of diabetic nephropathy. For instance, decreased autophagic activity has been shown in podocytes of the diabetic kidney, causing variations in podocyte function and subsequent disruption to the glomerular filtration barrier. Furthermore, attenuated autophagic activity has also been demonstrated in proximal tubular cells of the diabetic kidney, resulting in the buildup of impaired molecules and organelles, which are normally broken down by autophagy, leading to proteinuria. Moreover, necroptosis might have a key role in podocyte damage and subsequent decline in diabetic nephropathy. Thus, this article aims to review the mechanisms and effects of programmed cell death in diabetic nephropathy, including the roles of apoptosis, autophagy, and necroptosis.