In vivo tissue engineering of patient specific chimeric liver tissue for wholeorgan liver transplantation

每年，欧洲有超过7万名患者死于各种形式的肝功能衰竭。对于一些肝脏疾病，正在开发基于细胞的疗法、组织工程或基因疗法，但大多数患者将需要移植器官才能最终治愈。猪器官异种移植在肾脏、心脏和胰腺（胰岛）等器官移植中具有广阔的应用前景，利用多转基因猪器官控制免疫排斥反应已取得重大进展。然而，猪肝在很大程度上与人的生理机能不相容。因此，利用患者自身细胞再造异种肝脏有望使该器官适应特定患者。在这里，我们建议使用囊胚注射诱导多能干细胞（iPSCs）在小鼠和大鼠中产生受体来源的肝脏嵌合体。在一种新的器官移植动物模型中，我们将分析异体和异种支架嵌合肝脏的功能和细胞适应性。我们将采用免疫抑制策略，并分析受体来源的细胞替代程度、长期功能和可能的耐受性诱导。在实验动物实验的同时，我们将把猴和人的iPS细胞注射到GAL“^”/FAH“'”猪囊胚中，以产生大型嵌合动物，这是将嵌合肝脏概念转化为临床应用的重要一步。

Annually, more than 70.000 patients in Europe die fi'om various forms of liver failure. For some liver diseases cell based therapies, tissue engineering or gene therapies are being developed, but the majority of patients will require a transplantable organ for ultimate cure. Xenotransplantation of porcine organs is promising for kidney, heart or pancreas (islets), and significant progress hasbeen made in controlling the immunological rejection by using organs fi'om multi-transgenic pigs. The porcine liver, however, is largely incompatible with the human physiology.Repopulation of a xenogeneic liver by the patient's own cells could thus be promising to adapt the organ to a particular patient. Here, we propose to use blastocyst injection of induced pluripotent stem cells (iPSCs) to generate recipient derived liver chimeras in mice and rats. In a novel organ transplantation animal model we will analyze the fijnctionality and cellular adaptation of chimerized livers with allogeneic and xenogeneic scaffolds. We will employ immunosuppressive strategies and analyze the degree of recipient derived cellular substitution, long term fijnction and possible tolerance induction. In parallel to experiments with laboratory animals, we will inject monkey and human iPS cells into GAL"^"/FAH"'"porcine blastocysts to produce a large chimeric animal as an important step for translation of the chimeric liver concept towards clinical application.