EXPERIMENTAL LIVER PRESERVATION FOR TRANSPLANTATION

人类肝脏移植取得了显著的成功 在过去的5年中，由于提供了改进的免疫抑制 但临床上移植的选择通常是 减少，因为供体肝脏只能安全保存6到10年 几个小时。这种有限的保存减少了可用肝脏的数量， 使移植手术成为一项紧急程序，需要两个外科手术 团队，经常需要对一些病情最严重的外科医生进行手术 患者(即肝移植受者)在半夜。 建议的研究是一项全面的努力，以改善保存 捐赠者的肝脏。我们将使用DOG模型来：1)定义最佳条件 用于持续低温灌流(通过检查灌流效果 压力和通过灌流液注入的效果 肝动脉或门静脉，或两者兼而有之)；2)形成理想的灌流液(通过 检查电解液比例、肿胀压力和渗透压的作用 来自甘露醇和棉子糖的压力)；以及3)测试药物和其他 将肝脏损伤降至最低并促进肝脏恢复的药物 血运重建后的功能。调查人员将包括 酶抑制剂(别嘌醇和eHNA)，钙通道阻滞剂(硝苯地平， 地尔硫卓和维拉帕米)、O2-自由基清除剂(超氧化物歧化酶、过氧化氢酶、甘露醇、 和去铁胺)、膜稳定剂(氯丙嗪和 甲基强的松龙)和前列环素。 我们将使用体外组织切片模型来检测细胞活性，并 测定腺嘌呤核苷酸代谢、氧耗量、电解质 运输、组织浮肿和蛋白质合成。单元格结构将为 通过组织学分析和电子显微镜进行评估。 一个器官的生存能力和微循环的完整性将是 通过原位移植和光电子检查进行评估 活检标本的显微分析。最初的灌流液将是 一种是我们最近为保存肾脏而开发的，它包含 羟乙基淀粉为胶体，腺苷、葡萄糖酸盐、磷酸盐等。 这项工作的最终目标是一种临床保存的方法 供肝48至72小时，可用于肝移植 程序。

Human livers have been transplanted with dramatically increasing success during the past 5 years because of the improved immunosuppression provided by cyclosporin A. But the clinical option of transplantation is often reduced because donor livers can be safely preserved for only 6 to 10 hours. This limited preservation reduces the number of available livers, makes transplant surgery an emergency procedure requiring two surgical teams, and often necessitates operating on some of the sickest surgical patients (viz., liver transplant recipients) during the middle of the night. The proposed research is a comprehensive effort to improve the preservation of donor livers. We will use a dog model to: 1) define optimal conditions for continuous hypothermic perfusion (by examining the effects of perfusion pressures and the effects of administering the perfusate through the hepatic artery or portal vein, or both); 2) develop the ideal perfusate (by examining the roles of electrolyte ratio, oncotic pressure, and osmotic pressure derived from mannitol and raffinose); and 3) test drugs and other agents that minimize liver damage and facilitate the resumption of liver function after revascularization. The investigative agents will include enzyme inhibitors (allopurinol and EHNA), Ca channel blockers (nifedipine, diltiazem, and verapamil), O2-radical scavengers (SOD, catalase, mannitol, and desferrioxamine), membrane stabilizers (chlorpromazine and methylprednisolone) and prostacyclin. We will access cell viability, using an in vitro, tissue-slice model, and determine adenine nucleotide metabolism, O2 consumption, electrolyte transport, tissue edema, and protein synthesis. Cell structure will be assessed from histological analysis and electron microscopy. The viability of an organ and the integrity of its microcirculation will be assessed by orthotopic transplantation and by light and electron microscopic analyses of biopsy specimens. The initial perfusate will be one--which we recently developed for kidney preservation--that contains hydroxyethlstarch as the colloid, and adenosine, gluconate, phosphate, etc. The ultimate objective of this work is a method of clinically preserving donor livers for 48 to 72 hours that can be used in liver transplant programs.