A Natural Tetrahydropyrimidine Protects Small Bowel from Cold Ischemia and Subsequent Warm in vitro Reperfusion Injury

Abstract

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.