Abstract
Advanced glycation end products (AGEs) and their receptor (RAGE) play a role in diabetic
nephropathy. We have recently found that linagliptin, an inhibitor of dipeptidyl peptidase-4
(DPP-4) suppresses the AGE-induced oxidative stress generation and intercellular adhesion
molecule-1 (ICAM-1) gene expression in endothelial cells. However, whether linagliptin
could have beneficial effects on experimental diabetic nephropathy in a glucose-lowering
independent manner remains unknown. To address the issue, this study examined the
effects of linagliptin on renal damage in streptozotocin-induced diabetic rats. Serum
levels of DPP-4 were significantly elevated in diabetic rats compared with control
rats. Although linagliptin treatment for 2 weeks did not improve hyperglycemia in
diabetic rats, linagliptin significantly reduced AGEs levels, RAGE gene expression,
and 8-hydroxy-2′-deoxyguanosine, a marker of oxidative stress in the kidney of diabetic
rats. Furthermore, linagliptin significantly reduced albuminuria, renal ICAM-1 mRNA
levels, and lymphocyte infiltration into the glomeruli of diabetic rats. Our present
study suggests that linagliptin could exert beneficial effects on diabetic nephropathy
partly by blocking the AGE-RAGE-evoked oxidative stress generation in the kidney of
streptozotocin-induced diabetic rats. Inhibition of DPP-4 by linagliptin might be
a promising strategy for the treatment of diabetic nephropathy.
Key words
AGEs - RAGE - oxidative stress - DPP-4 - linagliptin - diabetic nephropathy