Intestinal transplantation: effects on ileal enteric absorptive physiology

Area of Science:

• Gastroenterology
• Surgical Physiology
• Intestinal Transport

Background:

• Small intestine transplantation's effects on enteric physiology are not well understood.
• Autotransplantation leads to severe diarrhea and weight loss in dogs.
• The underlying causes of post-transplant diarrhea remain unclear.

Purpose of the Study:

• To investigate jejunoileal autotransplantation's impact on ileal water, electrolyte, and bile salt absorption.
• To assess the effects of proabsorptive and prosecretory agents on ileal transport post-transplantation.

Main Methods:

• Dogs underwent jejunoileal neural and lymphatic isolation (a model of autotransplantation).
• Triple-lumen perfusion measured ileal water, electrolyte, and bile salt fluxes pre- and post-transplant (2 and 8 weeks).
• Vasoactive intestinal polypeptide and norepinephrine infusions evaluated their effects on ileal transport.

Main Results:

• Ileal absorption of water and electrolytes decreased immediately and at 2 weeks post-transplant, returning to baseline by 8 weeks.
• Net bile salt flux also decreased at 2 weeks, recovering by 8 weeks.
• Prosecretory response to vasoactive intestinal polypeptide was unchanged; proabsorptive response to norepinephrine increased.

Conclusions:

• Jejunoileal autotransplantation significantly reduces ileal absorption of water, electrolytes, and bile salts.
• Post-transplant diarrhea may stem from secretory mechanisms or bile salt malabsorption due to denervation.
• Ileal transport function recovers by 8 weeks after jejunoileal autotransplantation.