Functional monitors of rejection in small intestinal transplants

Absorption of cyclosporine and uptake of radiolabelled glucose by the transplanted small intestine in the dog was investigated to develop physiologic markers of rejection. Cyclosporine in olive oil was given orally, and glucose-14C was instilled into an isolated pouch constructed from the transplanted jejunum. Biopsies were simultaneously obtained from an isolated pouch made from the transplanted ileum. The absorption data were correlated with the histologic findings. Absorption of cyclosporine was of the same magnitude in autotransplanted dogs as it was in allotransplanted dogs with a normal graft. Absorption of cyclosporine in allotransplanted dogs with histologic signs of rejection was significantly reduced. Peak uptake of glucose-14C was noted 5 to 10 minutes after instillation of the isotope in autotransplanted and allotransplanted dogs with a normal graft. Allotransplanted dogs undergoing rejection had a delayed appearance of peak uptake and significantly reduced absolute uptake. In conclusion, absorption of cyclosporine and uptake of radiolabelled glucose can be utilized as functional monitors of intestinal allograft rejection.