Biliary bile acid profiles in patients with familial adenomatous polyposis before and after colectomy

The development of colorectal polyps and cancer in patients with familial adenomatous polyposis (FAP) is directly linked to inactivation of the APC gene. Other, epigenetic, mechanisms may be involved in tumorigenesis and a previous study suggested that an intrinsic difference in the biliary bile acid profile of untreated patients with FAP persisted after colectomy. Gas chromatography and gas chromatography-mass spectrometry were used to examine the biliary bile acid profiles of four groups of patients with normal gallbladders: 20 patients with an intact colon comprising 12 with FAP and eight controls; and 26 patients after colectomy comprising 12 with FAP and 14 controls. Comparison of ten different bile acids from both amidate fractions (glycine and taurine) revealed a small increase in the molar percentage of a minor bile acid (12-oxolithocholic acid) in patients with FAP and an intact colon compared with the matching control group. Colectomy was associated with a dramatic reduction in levels of secondary bile acids but with little difference between patients with FAP and controls.