Investigation of intestine and liver function in cirrhosis using combined sugar oral loads

Active and passive intestinal absorption and the efficiency of hepatic galactose clearance were studied in 12 patients with liver cirrhosis and 8 healthy control subjects using differential absorption techniques in which paired sugar markers were ingested simultaneously. Such differential absorption procedures overcome the effects of variation in gastric emptying, intestinal transit, distribution space and renal clearance which could invalidate tests incorporating a single marker only. In the cirrhotic group, active absorption of D-xylose (D-xyl) compared with that of 3-O-methyl-D-glucose (3-OMG), indicated by the ratio of D-xyl/3-OMG concentration in plasma, showed no reduction in respect to the control group. The passive intestinal permeability to lactulose (lac) compared with that of L-rhamnose (rham), indicated by urinary lac/rham excretion ratio, was not raised. These findings indicate no dysfunction of small intestinal mucosa in cirrhotic patients in spite of the clinical evidence of portal hypertension. Urinary galactose (gal) excretion after oral load was 10 times higher in the cirrhotic group (P less than 0.001). The gal/3-OMG excretion ratio correlated well with galactose elimination capacity as assessed by an intravenous method. Estimation of plasma D-xyl/3-OMG concentration and both urinary lac/rham and gal/3-OMG excretion ratios after appropriate oral loads provided a convenient and simultaneous evaluation of intestinal absorption, permeability and hepatic galactose elimination.