Renal function in compensated hepatic cirrhosis: Effects of an amino acid infusion and relationship with nitric acid

Aims: In order to assess the possible participation of nitric oxide (NO) in renal function during compensated hepatic cirrhosis, we studied renal func tion, the plasma and urinary levels of cGMP and the concentration of nitrat es and nitrites, as markers of NO synthesis in blood and urine, in 10 patie nts with Child A hepatic cirrhosis as compared with 10 control subjects, bo th under basal conditions and during stimulation (amino acid-induced glomer ular hyperfiltration). Methods: To study renal function, the glomerular fil tration rate (GFR), effective renal plasma flow (ERPF), renal functional re serve (RFR), renal venous resistance (RVR) and the filtration fraction (FF) were measured. Renin and aldosterone levels were determined to assess the possible involvement of these compounds in the renin-angiotensin-aldosteron e axis. Results: GFR and ERPF were significantly lower in the patients with cirrhosis than in the controls (mean GFR: 82+/-12.3 vs. 105+/-15 ml/min, p = 0.01; ERPF 452+/-86 vs. 543+/-56 ml/min, p = 6.662). The RFR value was s imilar in both groups. In the basal situation cGMP levels were higher in pl asma and urine in patients with cirrhosis than in the controls (plasma cGMP in cirrhosis 8.4+/-2.4 vs. 4.2+/-3.5 pmol/ml; urine cGMP in cirrhosis 1.2/-2.1 vs. 0.68+/-0.1 pmol/ml). The NO levels were also higher in plasma and urine in patients with cirrhosis vs. controls (plasma NO in cirrhosis 45.5 +/-9.2 vs. 30.3+/-1.2 mu mol/l; urinary NO in cirrhosis 6.2+/-1.3 vs. 3.1+/ -2.3 mu mol/ml). In both groups the amino acid perfusion increased GFR, ERP F, cGMP and NO levels in plasma and urine. In the patients with cirrhosis t he RVR decreased significantly during perfusion and no noteworthy changes i n FF were observed. The GFR values observed during amino acid perfusion wer e similar in patients with cirrhosis and portal hypertension to those obser ved in the controls (27.2+/-12 vs. 25.3+/-16%). However, the changes induce d the ERPF were more marked in patients with cirrhosis (cirrhosis 35.3+/-15 vs. 22.2+/-13%, p = 0.02). Conclusions: The present findings point to cert ain alterations in renal function in patients with hepatic cirrhosis and po rtal hypertension without ascitis, a clear difference being visible between the ERPF and GFR following amino acid-induced stimulation. The significant elevation in cGMP and NO levels in plasma and urine implies a maintained v asodilatory action that may at least partly compensate the vasoconstrictor effects of angiotensin II. Copyright (C) 2000 S. Karger AG, Basel.