REN and Hypertension: Although some studies have demonstrated that TGF-β1 is associated with increased risk of essential hypertension through the stimulation of endothelin-1 expression in the vascular endothelium, release of renin from the juxtaglomerular cells in the kidney, and regulation of angiotensin II expression [62–64], no study has evaluated the impact of this polymorphism on hypertension in patients with diabetes.