Acetate levels in cirrhosis

Lactulose has been successfully used in the treatment of portal-systemic encephalopathy but its exact mechanism of action is not known. The aim of this study was to observe the systemic effects of colonic fermentation of an acute lactulose dose in cirrhotic and normal subjects. Six cirrhotic patients and six normal subjects were placed on two identical 2-day metabolic diets, one of which was supplemented with lactulose (1g/100 kcals to a maximum of 28g/day). Lactulose increased colonic fermentation in cirrhotic and normal subjects as evidenced by significantly higher breath hydrogen and acetate levels. The change in serum acetate levels after lactulose ingestion was not different between cirrhotics and normals. The higher levels of acetate (p = 0.039) observed in the cirrhotics indicates an increased endogenous production and decreased peripheral utilisation of acetate by the cirrhotic liver. No change was observed in blood ammonia, glucose, insulin or free fatty acid levels with lactulose.