Increased plasma carbon monoxide in patients with viral cirrhosis and hyperdynamic circulation.

Abstract OBJECTIVES: Our aim was to measure plasma carbon monoxide (CO) in patients with liver cirrhosis and portal hypertension. METHODS: In 36 cirrhotic patients (24 with ascites) and 9 healthy volunteers, we evaluated CO plasma levels and systemic hemodynamics (using ultra-trace gas chromatography and echocardiography, respectively). Heme oxygenase (HO) activity and expression were measured in isolated polymorphonuclear (PMN) cells. RESULTS: Plasma CO level (mean+/-s.d.) was 5.81+/-1.31 p.p.m. in healthy subjects (HS), significantly higher in non-ascitic patients (16.24+/-4.61 p.p.m., P<0.01), and even more high in ascitic patients (28.50+/-7.27 p.p.m., P<0.01 vs. the other two groups). HO activity in PMN cells was significantly greater in patients than in HS, with the highest levels being observed in patients with ascites. Western blot analysis showed enhanced expression of HO-1, but not HO-2. In the whole series of cirrhotic patients, plasma CO levels directly correlated with cardiac output, and inversely with systemic vascular resistance and mean arterial pressure. CONCLUSIONS: The HO/CO system is activated in patients with liver cirrhosis. This could contribute to the hyperdynamic circulatory syndrome observed in this condition.