Brain natriuretic polypeptide in type 2 NIDDM patients with albuminuria.

We investigated plasma brain natriuretic polypeptide (BNP) in Type 2 NIDDM patients with albuminuria. This study involved normal control subjects (Controls), hypertensive patients without diabetes mellitus (HT) and Type 2 NIDDM patients. Diabetic patients were divided into 4 groups by urinary albumin index (Alb-I): group I <30; group II 30-149; group III 150-300; group IV >300 mg/g creatinine. BNP levels in group III or IV were significantly higher than in Controls. The diabetic patients were re-divided into 4 groups (DM: with neither diabetic retinopathy (which was one of indicators of microangiopathy) nor hypertension, DM+HT: without diabetic retinopathy and with hypertension, DM+R: with diabetic retinopathy and without hypertension and DM+R+HT: with both diabetic retinopathy and hypertension). The Alb-I levels in DM+HT and DM+R+HT were significantly higher than the Controls, indicating the development of diabetic nephropathy in those groups. BNP levels in DM+HT, DM+R or DM+R+HT were significantly higher than in Controls. This indicates that BNP levels elevate in diabetic patients with increased albuminuria due to hypertension or microangiopathy deteriorating diabetic nephropathy. Elevated plasm BNP may play a pathophysiological role in the development of diabetic nephropathy.