Serum nitric oxide levels in chronic renal failure patients on maintenance hemodialysis

Background: Nitric oxide (NO) is an endothelium derived vasodilator. NO regulates renal function through modulation of vascular tone. With the progressive development of renal insufficiency, it remains unclear whether endogenous NO production is increased or decreased in the kidney. Aim: This study was carried out to evaluate NO levels and its correlation to routine parameters of renal dysfunction in patients of chronic renal failure (CRF) on maintenance hemodialysis (MHD) in comparison to healthy controls. Material and Methods: 30 CRF patients on MHD with serum creatinine levels >2.5 mg/dl were included in the study along with 30 healthy controls. Serum NO was estimated by spectrophotometric method using cadmium reduction. Routine renal function tests; blood urea nitrogen (BUN) and creatinine were performed by standard clinical chemistry procedures. The between-group differences and between-variable correlations were studied by the independent sample t-test and Pearson correlation analyses, respectively. The receiver operating characteristic curve (ROC) analysis was performed to obtain the sensitivity, specificity and area under curve (AUC) values for serum NO. Results: The serum NO levels were found to be significantly increased (p 0.01) in CRF on MHD (96.5 26.22 ?mol/l) as compared to the controls (40.57 13.36 ?mol/l). NO output correlated with serum creatinine (r=0.615, p 0.01) and BUN (r=0.584 ,p= 0.01) in the CRF group. The ROC analysis on serum NO discriminated between CRF patients and controls with good sensitivity (93.3%), specificity (96.1%) and AUC (0.95) results at a cut-off value of 72.5 mol/L. Conclusions: Our study findings of increased serum NO level and its significant positive correlations with BUN and creatinine in CRF patients on MHD suggests an altered endothelial function in CRF patients on MHD. This increase in serum NO has been found to be useful in discriminating patients from controls.