In vivo assessment of the influence of cold preservation time on microvascular reperfusion injury after experimental small bowel transplantation

Background This study describes the impact of prolonged cold storage on microvascular reperfusion injury of transplanted rat small bowel isografts. Methods In vivo fluorescence microscopy was used to assess intestinal microcirculation after 6, 12, 18 and 24 h of cold (4 degrees C) ischaemia in University of Wisconsin solution and 20-90 min of reperfusion. Sham-operated animals served as controls. Results Whereas 6 and 12 h of ischaemia did not affect functional capillary density of the intestinal graft mucosa, villous perfusion was significantly impaired after 18 and 24 h of cold preservation. Similarly, microvascular perfusion of circular and longitudinal muscle was not affected after 6 h, but deteriorated following prolonged cold ischaemia. Leucocyte-endothelial cell interaction in submucosal venules was significantly enhanced after 6 h of ischaemia with peak values after 12 and 18 h. A progressive reduction of lymphatic capillary drainage indicated an ischaemia time-related deterioration in graft function. Conclusion The results provide evidence that leucocyte-endothelial cell interaction in submucosal venules of the transplanted intestine is a primary step in the manifestation of reperfusion injury following short periods of cold ischaemia.