Carolina rinse attenuates postischemic microvascular injury in rat small bowel isografts

Abstract

Background: Apart from rejection-related events, the manifestation of ischemia/reperfusion (I/R) injury remains a major problem, hampering success in human small bowel transplantation (SBTx). Therefore the aim of this study was to determine the potential of Carolina rinse (CR) to attenuate microvascular reperfusion injury in rat intestinal isografts.

Methods: After 18 hours of cold preservation in 4 degrees C University of Wisconsin solution (UW), rat SBTx was performed. Immediately before reperfusion the intestine was flushed with 4 degrees C or 37 degrees C Ringer's lactate (RL, groups 1 and 2) or CR (groups 3 and 4), respectively. In vivo fluorescence microscopy was used to analyze the grafts' microcirculation.

Results: In group 1 severe microvascular I/R injury was observed in mucosa and muscle layers. Microcirculatory deterioration was paralleled by enhanced leukocyte accumulation in submucosal venules and by impaired subserosal lymphatic capillary drainage (FCLD). Rinsing the grafts with 37 degrees C RL attenuated leukocyte-endothelial cell interaction and improved subserosal FCLD; however, it did not affect mucosal microvascular reperfusion damage. In contrast, 4 degrees C CR dramatically improved nutritive perfusion within muscle and mucosa (p < 0.05) and attenuated leukocyte adherence within submucosal venules (p < 0.05). Additional prewarming of CR almost completely prevented mucosal I/R injury (p < 0.05 versus group 3) and caused a fourfold increase of FCLD. CONCLUSIONS. With this study we demonstrate that CR in combination with rewarming of the graft before reperfusion is an effective regimen to prevent leukocyte accumulation and to counteract microvascular injury after SBTx.