Oral arginine improves blood pressure in renal transplant and hemodialysispatients

Background: Hypertension in kidney transplant (KT) patients may result from attenuated whole-body nitric oxide (NO) content and abnormal NO-mediated v asodilation. Increasing NO bioavailability with L-arginine (ARG) could theo retically restore the NO-mediated vasodilatory response and lower blood pre ssure. Methods: In a prospective pilot study, 6 normotensive volunteers and 10 KT patients received oral supplements of ARG (9.0 g/d) for 9 days, then 18.0 g/d for 9 more days. Six hemodialysis (HD) and 4 peritoneal dialysis patients received the same dose for 14 days. Five KT patients received 30 m L/d of canola oil (GanO) in addition to ARG. Systolic (SBP) and diastolic ( DBP) blood pressure, creatinine clearance (CCr), and serum creatinine (Cr) were measured at baseline, day 9, and day 18. In a subsequent study, 20 hyp ertensive KT patients with stable but abnormal renal function were randomiz ed in a crossover study to start ARG-only or ARG+CanO supplements for two 2 -month periods with an intervening month of no supplementation. SBP, DBP, C Cr, and Cr were measured monthly for 7 months. Results: In the pilot study, ARG reduced the SBP in HD patients from 171.5 +/- 7.5 mmHg (baseline) to 1 42.8 +/- 8.3 mmHg (p = .028). In the crossover study, SBP was reduced from baseline (155.9 +/- 5.0 mmHg), after the first 2 months (143.2 +/- 3.2 mmHg ; p = .03) and subsequent 2 months (143.3 +/- 2.5 mmHg; p = .014) of supple mentation. DBP was also reduced after supplementation in both studies. CanO had no effect on blood pressure. Renal function did not change. Conclusion s: Oral preparations of ARG ( CanO) were well tolerated for up to 60 consec utive days and had favorable effects on SBP and DBP in hypertensive KT and HD patients.