Glutamine distribution in patients with ulcerative colitis and in patients with familial adenomatous polyposis coli before and after restorative proctocolectomy

Abstract

Background and aims: Restorative proctocolectomy with construction of an ileoanal pouch (IPAA) is the surgical treatment of choice for patients with ulcerative colitis (UC) or familial adenomatous polyposis (FAP). This procedure imposes an essential change in function on the terminal ileal mucosa and pouch mucosa. Glutamine is one of the major nutrients for the small-bowel mucosa; it is metabolized into glutamate and subsequently alanine in the human enterocyte. In a prospective clinical trial we compared glutamine distribution in patients with UC to that in patients with FAP before and after restorative proctocolectomy.

Methods and patients: Concentrations of glutamine, glutamate, and alanine were measured pre- and postoperatively in the terminal ileal mucosa, pouch mucosa, skeletal muscle and venous blood of patients undergoing IPAA for UC or FAP. Healthy individuals served as controls for skeletal muscle glutamine concentration.

Results: After IPAA the glutamine concentration in UC patients was decreased in skeletal muscle. In the mucosa glutamine remained unaltered while glutamate and alanine concentrations increased. In plasma the glutamine concentration increased, the glutamate level fell, and the alanine level increased. In FAP patients the glutamine level was unchanged in skeletal muscle after IPAA. In mucosa the glutamine level did not change, but glutamate and alanine increased. In plasma the glutamine level remained unaltered, glutamate decreased, and alanine increased.

Conclusion: Patients with UC or FAP before surgical therapy do not suffer from glutamine depletion. IPAA resulted in changes in the distribution of glutamine and its metabolites in skeletal muscle, plasma, and ileal pouch mucosa, particularly in patients with UC. Further studies should investigate whether characteristics in the glutamine distribution have any impact for the long-term outcome after IPAA.