LIVER REPOPULATION FOR LIVER INJURY AND GENE THERAPY

肝细胞移植具有巨大的基因治疗潜力， 用于治疗急性肝衰竭。因为肝细胞具有细胞的 表达多种基因的机器，其用于离体基因 治疗是特别有吸引力的。同样，肝细胞移植 应该为急性肝衰竭提供新的治疗方法， 导致大于80%的不可接受的死亡率。虽然 原位肝移植可用于急性肝衰竭， 这是一个艰巨而不可逆转的过程。相比之下， 肝细胞移植的优点包括技术简单， 将从单个肝脏制备的细胞移植到 多个受体和冷冻保存和移植细胞的潜力 我就能把他带走然而，尽管应用肝细胞非常紧迫， 人类移植，更好地了解生物学， 移植的肝细胞是最佳使用所必需的。 我们假设肝细胞移植的成功需要： 确定肝细胞存活的允许条件， B）确定增加 移植肝细胞，和c）优化的时间和剂量， 治疗应用所需的细胞。开始解决这些问题 关键问题，我们开发了新的系统， 明确区分移植肝细胞和宿主肝细胞 细胞此外，我们证明了移植的肝细胞存活， 在肝脏中发挥最佳作用。我们现在建议审查机制 调节移植肝细胞在肝脏中的增殖和命运。我们 将检查移植肝细胞的增殖能力， 确定是否使用肝脏再生刺激可以增加质量 移植肝细胞的当肝细胞移植到 肝脏可能受到肝血管床容量的限制，我们将 确定肝细胞移植的安全性。利用来自 从这些研究中，我们将制定大规模重建的战略， 宿主的肝脏这些策略将在强大的动物中进行测试 遗传代谢疾病的模型。此外，急性肝损伤的动物模型 失败将用于定义肝细胞的时间、剂量和值 移植，以及同时给予肝生长 因素最后，肝细胞前体细胞将用于确定 其值与原代肝细胞相比。完成这些 拟议的研究将大大推进我们的基本知识， 肝细胞移植，帮助这项技术从 实验室到床边

Hepatocyte transplantation has an immense potential for gene therapy and for treating acute liver failure. Because hepatocytes possess the cellular machinery to express a variety of genes, their use for ex-vivo gene therapy is particularly attractive. Similarly, hepatocyte transplantation should provide novel therapies for acute liver failure, which currently results in unacceptable mortalities of greater than 80%. Although orthotopic liver transplantation can be employed in acute liver failure, this is a formidable and irreversible procedure. In contrast, advantages of hepatocyte transplantation include its technical simplicity, the possibility of transplanting cells prepared from a single liver into multiple recipients and the potential to cryopreserve and transplant cells at a short notice. However, despite a great urgency in applying hepatocyte transplantation in humans, a better understanding of the biology of transplanted hepatocytes is required for an optimal usage. We hypothesize that the success of hepatocyte transplantation requires a) identification of permissive conditions for hepatocyte survival and function, b) identification of methods to increase the mass of transplanted hepatocytes, and c) optimization of the time and dose of cells required for therapeutic applications. To begin addressing these critical issues, we developed novel systems with genetically marked hepatocytes to unequivocally distinguish between transplanted and host cells. Also, we demonstrated that transplanted hepatocytes survive and function most optimally in the liver. We now propose to examine mechanisms regulating proliferation and fate of transplanted hepatocytes in liver. We will examine the proliferative capacity of transplanted hepatocytes and determine whether use of liver regenerative stimuli could augment the mass of transplanted hepatocytes. As transplantation of hepatocytes into the liver may be limited by the capacity of the hepatic vascular bed, we will determine the safety of hepatocyte transplantation. Using insights derived from these studies, we will develop strategies for massive reconstitution of the host liver. These strategies will be tested in powerful animal models of genetic metabolic disease. Also, animal models of acute liver failure will be used to define the timing, dose and value of hepatocyte transplantation, a well as simultaneous administration of hepatic growth factors. Finally, hepatocyte precursor cells will be used to determine their value compared with primary hepatocytes. Completion of these proposed studies will greatly advance our fundamental knowledge of hepatocyte transplantation and help move this technology from the laboratory to the bedside.