Enhanced reduction of proteinuria of renal transplant with biopsy-proven chronic allograft nephropathy by dual combination of renin-angiotensin system blockers

초록

Background Blockade of the renin&#8211;angiotensin system (RAS) decreases progression in chronic kidney disease with proteinuria , but the effect on renoprotection of ranal transplant with CAN is as yet unclear. We evaluated the effects of dual blockade of renin&#8211;angiotensin system (RAS) by low-dose combination of angiotensin converting enzyme inhibitor(ACEi) and angiotensin II receptor blocker(ARB) in proteinuric patients with biopsy-proven CAN. Methods. We performed a prospective randomized crossover trial consisting of three 16-weeks treatment periods with ramipril alone (10 mg/day), olmesartan alone (20 mg/day), and ramipril (5 mg/day) plus olmesartan (10 mg/day) combination therapy. Thirteen proteinuric patients with biopsy-proven CAN with a 24 h urinary protein excretion rate (UPER) of >1.0 g/24 h and estimated glomerular filtration (eGFR) of 30 to 59 ml/min/1.73 m2. Results. Subjects consisted of 7 female and 6 male patients with a mean age of 49±7 years and duration of renal transplantation ranging from 6 to 13 years. At baseline, 24-h blood pressures (BPs) were 145±6/74±7 mmHg, eGFR 42.3±4.1 ml/min/1.73 m2, 24-h UPER 2.5±1.2 g/24 h. Although there was no comparable change in BP, eGFR and other plasma/urinary biochemical parameters, 24-h UPER was significantly reduced by the combination therapy (1.5±1.3 g/24 h) compared with that of ramipril (2.0±1.7 g/24 h) and of olmesartan (1.9±1.3 g/24 h) single therapy (P<0.05).