Glomerular Injury of Preeclampsia

OBJECTIVE: To assess the benefit of L-arginine, the precursor to nitric oxide (NO), to blood pressure and recovery of the glomerular lesion in pre-eclampsia. METHODS: 45 women with pre-eclampsia were randomized to receive either L-arginine or placebo until day 10 post-partum. Primary outcome measures including MAP, glomerular filtration rate and proteinuria were assessed on the third and tenth days postpartum by inulin clearance and albumin-to-creatinine (A/C) ratio. NO, cyclic guanosine 3'5' monophosphate (cGMP), endothelin-1 (ET) and asymmetric-dimethyl-arginine (ADMA) and arginine levels were assayed prior to delivery, on the third and tenth day postpartum. Healthy gravid women provided control values. Assuming a standard deviation of 10 mmHg, the study was powered to detect a 10 mmHg difference in MAP (alpha 0.05, beta 0.20) between the study groups. RESULTS: No significant differences existed between the groups with pre-eclampsia prior to randomization. Compared to the gravid control group, women with pre-eclampsia did not reveal significantly depressed levels of serum arginine, but did reveal significantly increased serum levels of ET, cGMP and ADMA prior to delivery. Despite a significant increase in serum arginine levels due to treatment, no differences were found in the levels of NO, ET, cGMP or ADMA between the two groups with pre-eclampsia. Further, there were no significant differences in any of the primary outcome measures with both groups demonstrating equivalent improvements in both blood pressure and proteinuria. CONCLUSION: Blood pressure and kidney function improve markedly in pre-eclampsia by the tenth day postpartum. L-arginine supplementation does not hasten this recovery.