Changes of ascites nitric oxide according to the treatment course in cirrhotic patients with spontaneous bacterial peritonitis

BACKGROUND/AIMS: Nitric oxide (NO) is a molecule involved in vascular dilatation and pathogen suppression. It also has immunologic and regulatory functions. Liver cirrhosis is characterized by an increased risk for bacterial infections, including spontaneous bacterial peritonitis (SBP). The role of NO in SBP which develops in cirrhosis has not been clearly established. The aim of this study was to investigate the role of NO in the pathogenesis of SBP and its clinical usefulness for prediction of disease prognosis. METHODS: This study was designed to investigate the changes of ascites NO in the course of treatment. Nitric oxide metabolite (nitrites+nitrates [NOx]) was measured by chemiluminescence in 84 ascites samples obtained from 84 cirrhotic patients. Among them, the 38 patients with SBP were treated with cefotaxime 2.0 g, q 12hr for 7 days. In 24 of SBP patients, ascites was obtained consecutively before treatment (day 0), during treatment (day 2), and after treatment (day 7). RESULTS: Ascites NO levels in the patients with SBP (n=38; 82.3 +/- 14.4 microM) were not different from those in patients with sterile ascites (n=46; 54.6 +/- 13.0 microM). There was no significant change of NO levels in sequential ascites samples during antibiotic treatment. Ascites NO level before treatment was significantly higher in SBP patients who responded to antibiotics (n=26; 101.86 microM/L) than that in SBP patients who did not respond to antibiotics (n=12; 40.03 microM/L, P=0.044). A significant direct correlation was found between ascites and serum NO levels before treatment (Pearson correlation, r2=0.86, P=0.001). Among the SBP patients, treatment response rate to antibiotics were significantly higher in those patients with pretreatment NO level > or = 80 microM/L in multivariate analysis. CONCLUSIONS: Ascites NO level was not different between ascites from SBP patients and ascites from cirrhotic patients with sterile ascites. There were no changes of ascites NO in SBP patients during treatment. Therefore ascites NO was not useful to predict the progress of SBP. Ascites NO levels reflect serum NO levels, and the patients with higher NO level may have better response to antibiotics.