Combined Aliskiren and Amlodipine Reduce Albuminuria via Reduction in Renal Inflammation in Diabetic Rats

Abstract

We hypothesized that compared with hydrochlorothiazide (HCTZ), the renin inhibitor aliskiren (ALISK) or amlodipine (AMLO) and their combination reduce albuminuria via reduction in renal inflammation, independent of blood pressure (BP) changes. We studied normal and streptozotocin-induced diabetic (DM) Sprague-Dawley rats treated for 6 weeks with vehicle, ALISK, HCTZ, or AMLO individually and combined and evaluated the effects of treatments on BP, urine albumin to creatinine ratio, renal interstitial fluid levels of angiotensin II, tumor necrosis factor alpha (TNF-α), and interleukin 6 (IL-6) and renal expression of TNF-α, IL-6, transforming growth factor beta 1, and nuclear factor kappa B. There were no differences in BP between treatments. Only ALISK and its combinations reduced renal interstitial fluid angiotensin II. Urine albumin to creatinine ratio increased in DM rats and decreased with ALISK alone or combined with HCTZ or AMLO. HCTZ or AMLO individually and combined did not influence urine albumin to creatinine ratio. Renal interstitial fluid TNF-α and IL-6, and the renal expression of TNF-α, IL-6, transforming growth factor beta 1, and nuclear factor kappa B were increased in DM rats. These renal inflammatory markers were reduced only with ALISK or AMLO individually or combined with other treatments. We conclude that ALISK alone and combined with HCTZ or AMLO reduced albuminuria in diabetes via reduction in renal inflammation, independent of BP changes.