Diabetic nephropathy (DN) is the most common renal complication of diabetes mellitus and a leading cause of end-stage renal disease. The renin-angiotensin system (RAS) is a major mediator of progressive renal injury in DN, and RAS inhibitors have been used as the mainstay treatment for DN. [Note: the RAS is a hormone system that regulates the balance of blood pressure and blood/fluid volume in the body.]
One major problem limiting the efficacy of the RAS inhibitors is the compensatory renin increase caused by disruption of renin feedback inhibition.
Vitamin D negatively regulates the RAS by suppressing renin expression and thus plays a renoprotective role in DN.
Diabetic vitamin D receptor-null mutant mice develop more severe renal injuries because of more robust RAS activation.
Combination therapy with an RAS inhibitor and a vitamin D analogue markedly ameliorates renal injuries due to blockade of the compensatory renin increase by the analogue.
These most recent data demonstrate that vitamin D and its analogues have renoprotective and therapeutic potentials in DN through targeting the RAS.
Source: Current Diabetes Reports, 2008, 8:464-469. Chun Li Y. Department of Medicine, University of Chicago, Chicago, Illinois, USA. [E-mail: email@example.com]