Effect of lactulose on biliary lipid composition.

Area of Science:

• Gastroenterology
• Hepatology
• Bile Acid Metabolism

Background:

• Bile acid composition influences biliary cholesterol saturation.
• Secondary bile acids, like deoxycholate, are produced by colonic bacteria.
• Lactulose is hypothesized to reduce secondary bile acids, potentially decreasing gallstone risk.

Purpose of the Study:

• To investigate the effect of lactulose on biliary deoxycholate levels.
• To determine if lactulose administration impacts biliary cholesterol saturation.
• To assess the role of colonic bacterial bile acid metabolism in gallstone formation.

Main Methods:

• Eight healthy females with colonic polyps and slightly elevated biliary cholesterol saturation received 60g lactulose daily for 12 weeks.
• Biliary deoxycholate, cholate, and chenodeoxycholate levels were measured.
• Biliary cholesterol saturation was assessed at baseline, 4 weeks, and 12 weeks.

Main Results:

• Lactulose administration led to a significant reduction in biliary deoxycholate (38% at 4 weeks, 32% at 12 weeks).
• This reduction occurred with a concurrent increase in primary bile acids (cholate and chenodeoxycholate).
• No significant changes in biliary cholesterol saturation were observed after 4 or 12 weeks of lactulose treatment.

Conclusions:

• Lactulose effectively reduces secondary bile acid deoxycholate in bile.
• The study does not support the hypothesis that colonic bacterial bile acid metabolites significantly contribute to supersaturated bile or cholesterol gallstone formation.
• Further research is needed to fully elucidate the complex interplay between gut microbiota, bile acid metabolism, and gallstone pathogenesis.