Bile Acid Metabolism in Patients with Crohn's Disease in Terminal Ileum

Abstract

Bile acid metabolism was studied by means of the fractional turnover rate or orally ingested ¹⁴C-labeled taurocholic acid and by gas chromatographic determination of fecal excretion of the bile acids cholic acid (CA), chenodeoxycholic acid (CDCA), deoxycholic acid (DCA), and lithocholic acid (LCA). Thirty patients with Crohn's disease (CD) of the small bowel, of whom 19 had been operated on with limited ileal resections, were studied and compared with 11 healthy volunteers. The unoperated group of CD patients did not show significant increase in bile acid excretion in the stools in contrast to the CD patients with ileal resection. The fecal excretion consisted mostly of primary bile acids, and a significant correlation between length of resection and bile acid excretion was found (r_s = 0.81, p < 0.01). The fractional turnover rate of CA + DCA was significantly increased in both unoperated (0.211/day) and operated (0.441/day) patients compared with normal controls (0.061/day). The bile acid pool of CA + DCA, however, was normal in patients with ileal resections, indicating a compensatory increase in bile acid synthesis. In unoperated patients the bile acid pool of CA + DCA was slightly decreased (3.1mmol) compared with operated patients (6.2 mmol) and normal controls (4.8 mmol). The pool size was not significantly correlated to mean transit time of dietary residue, feces excretion, loss of weight, or amount of fat in feces. The mean transit time of dietary residue was decreased in both operated and unoperated CD patients.

Key Words:

• Bile acid metabolism
• Crohn's disease
• dietary residue
• fat in feces
• fractional turnover rate
• mean transit time
• pool size
• synthesis rate