A natural tetrahydropyrimidine protects small bowel from cold ischemia and subsequent warm in vitro reperfusion injury.

OBJECTIVE Ischemia/reperfusion (I/R) injury is a major difficulty in small bowel transplantation. Many postoperative complications are caused by damage to the intestinal mucosa following organ retrieval and during cold storage. Here we investigate whether 1-, 4-, 5-, 6-tetrahydro-2-methyl-4-pyrimidine carboxylic acid (THP) can protect ileal mucosa and muscularis against cold ischemia and subsequent warm in vitro reperfusion injury. METHODS Small rat bowels were stored in the absence or presence of THP or its synthetic derivative lauryl-THP for 18 h at 4 degrees C. Several biochemical parameters were evaluated following isolated reperfusion in tissue grafts and/or effluent solution. Graft morphology was analyzed by electron microscopy. Ceramide was quantified as a potential target of THP action. RESULTS THP considerably inhibited apoptosis and improved all parameters illustrating membrane and subcellular integrity and functionality. Parallel studies with lauryl-THP failed to show a similar protective effect. Lauryl-THP, in contrast to THP, also failed to decrease tissue ceramide content, indicating the involvement of this well-known mediator of cellular stress response. CONCLUSIONS THP effectively protects ileal mucosa and muscularis against ischemia and reperfusion injury, indicating for the first time the clinical relevance of this new and promising molecule that might become a central component in tissue and organ protection in the near future.