In a rat model of streptozotocin-induced diabetic nephropathy, aliskiren plus paricalcitol decreased renal interstitial fibrosis volume but it showed no additional effect on oxidative stress, antioxidants, renin-angiotensin system and histology of the diseased kidneys when compared to monotherapy with aliskiren or paricalcitol [32]. The gene discussed is REN; the disease is diabetic kidney disease.