The effect of vardenafil (a PDE type 5 inhibitor) on renal function in the diabetic rabbit: a pilot study

Diabetic nephropathy is a common cause of impaired renal function. We investigated the effect vardenafil, a phosphodiesterase type 5 (PDE-5) inhibitor, has on renal function in the diabetic rabbit.

Blood was taken at 4 and 6 months from control and alloxan-induced diabetic animals (n=8, in each group) and biochemical variables pertaining to renal function determined. A 7-month sample was also analysed after giving control and diabetic animals (n=4 in each group) either vardenafil (3 mg/kg) or vehicle to drink for 4 weeks. Spot urine total protein/ creatinine ratio (TP/C) was determined at 4 and 6 months. At 7 months a 24 h-urine sample was collected to measure TP/C and creatinine clearance (CrCl).

There was a significant increase in serum creatinine concentration after 6 months diabetes, which was significantly reduced by vardenafil. TP/C from diabetic rabbit spot urine samples at 6 months were significantly elevated compared to control animals, indicating the presence of proteinuria. Vardenafil treatment caused a normalisation of TP/C. Diabetic animals receiving vardenafil showed a significant improvement in CrCl when compared with diabetic animals given vehicle.

These findings highlight a potential role for vardenafil in the treatment of diabetic nephropathy.