Azelnidipine has been reported to have
antioxidant effects and attenuates tubulointerstitial
ischemia. The aim of the present study was to determine whether
azelnidipine exerts additional renoprotective effects to
angiotensin II receptor blockers (ARBs) in hypertensive patients with
diabetic nephropathy and microalbuminuria. 45 hypertensive patients with
diabetes mellitus and microalbuminuria who were already being treated with ARBs were enrolled in this study.
Azelnidipine was added to the drug treatment of 30 patients (8 mg/day, n = 15, or 16 mg/day, n = 15) whilst the remaining 15 control patients were not treated with
azelnidipine. In all patients, urinary
8-hydroxydeoxyguanosine (8-OHdG) levels and urinary liver-type
fatty acid-binding protein (L-FABP) levels were significantly correlated (r = 0.587, p = 0.0006). However, urinary
albumin excretion (UAE) was not correlated with the levels of urinary 8-OHdG (r = 0.1975, p = 0.2956) or urinary L-FABP (r = 0.2057, p = 0.2759).
Azelnidipine significantly reduced UAE, urinary 8-OHdG and urinary L-FABP after 6 (p < 0.05) and 12 months (p < 0.05). Although blood pressure was comparable between the
azelnidipine doses of 8 and 16 mg/day, the UAE (p < 0.05 after 12 months), urinary 8-OHdG (p < 0.05 after 6 and 12 months) and urinary L-FABP (p < 0.05 after 6 and 12 months) levels were more significantly reduced in patients receiving the higher dose of 16 mg/day. These data may suggest that the addition of
azelnidipine treatment to
therapy with ARBs has dose-dependent
antioxidant and renoprotective effects beyond blood pressure-lowering effects in hypertensive
diabetic nephropathy patients.