诱导多能干细胞（iPSCs）分化的肝细胞在肝移植前、后对肝脏保护作用的研究

Liver transplantation is a successful treatment for end-stage liver diseases. However, there is a profound shortage of transplantable donor livers. Hepatocyte transplantation (HT) has been proposed as alternative therapeutic approaches to address the shortage of transplantable livers. However, the demand for human hepatocytes, heavily outweighs their availability by conventional means..Living donor liver transplantation (LDLT) has also been developed to increase the number of donor livers. However, the survival rate of adult recipients undergoing LDLT is significantly lower than that of children. Size mismatch of the graft and the recipient remains a major risk factor contributing to impaired post-operative graft function. Small-for-size liver grafts show delayed and impaired regeneration. Moreover, small-for-size liver grafts encounter several risks of graft failure after reperfusion, and accelerated acute rejection process, which frequently leads to liver failure termed “small-for-size syndrome”. Therefore, immediate regeneration is required for the hepatic mass recovery in LDLT settings, and subsequent protective measures are required for the maintenance of liver function..Induced pluripotent stem cells (iPSCs) could prove to be an unlimited source of hepatocytes. For clinical application, the all-autologous setting seems to be the most promising approach. Because iPSCs can bypass the ethical concerns of embryo destruction related to the derivation of embryonic stem cells and potential issues of allogenic rejection, iPSCs may represent a more ideal source to produce patient-specific and disease-specific adult cells for future clinical applications..The hepatocyte-like cells (HLCs) generated from iPSCs have been shown to secrete human albumin, synthesize urea, and express human cytochrome P450 enzymes, which provide an unlimited source of human hepatocytes for HT, and can enhance the liver regeneration after LDLT. .In this study, we are to explore first with a rat ALF model, and test whether transfusion of HLCs protecte damaged livers, and then using a 40% small-for-size liver transplantation model, and test whether transfusion of HLCs can promote regeneration after transplantation. This approach may create a better understanding of the principles behind successful treatment of end stage liver disease, both pre- and post- small-for-size liver transplantation.

供肝匮乏致大量患者在等待供肝期间死亡。肝细胞移植(HT)作为急性肝衰(ALF)患者等待供肝期间的过渡治疗，暂时缓解供肝缺乏，但肝细胞来源受限，且有排斥问题；活体肝移植(LDLT)部分缓解供肝匮乏，但小肝移植时肝细胞再生能力减弱，须采取措施维持肝功能，促进肝再生，以防发生小移植物综合症(SFSS)。来源于病人自身的诱导多能干细胞(iPSCs)能分化为肝细胞样细胞(HLCs)，可作为肝移植前HT的细胞来源，LDLT后输注HLCs可促进小肝再生，且避免被机体排斥。体外诱导分化的HLCs无法足够成熟，ALF和小肝移植的损伤微环境有利于输注的HLCs定植、进一步成熟和发挥功能。本课题用iPSCs来源的HLCs分别经门静脉输注ALF、小肝移植大鼠，观察HLCs在ALF模型中肝移植前行HT的治疗作用、LDLT后对小肝的保护作用，达到合理、科学利用供肝资源，解决供肝匮乏及其导致的系列问题。

供肝匮乏致大量患者在等待供肝期间死亡。肝细胞移植(HT)作为急性肝衰(ALF)或者慢性肝衰竭急性发作患者等待供肝期间的过渡治疗，暂时缓解供肝缺乏，但肝细胞来源受限，且来自异体的肝细胞移植有排斥问题；活体肝移植(LDLT)部分缓解供肝匮乏，但小肝移植时肝细胞再生能力减弱，必须采取措施维持小移植肝功能，促进肝再生，以防发生小移植物综合症（SFSS）。来源于病人自身的诱导多能干细胞（iPSCs）能分化为肝细胞样细胞(HLCs)，可作为肝移植前HT的细胞来源；LDLT后输注HLCs可促进小肝再生，且避免被机体排斥。体外诱导分化的HLCs无法足够成熟，ALF和小肝移植的损伤微环境有利于输注的HLCs定植、进一步成熟和发挥功能。本课题用iPSCs来源的HLCs分别经门静脉输注ALF、小肝移植大鼠，观察HLCs定植、成熟及促肝再生、预防SFSS、提高存活率等指标，研究iPSCs来源的HLCs在ALF模型肝移植前行HT的治疗作用、LDLT后对小肝的保护作用。本研究的结果显示HLCs输注可以治疗ALF，促进小移植肝再生，降低SFSS发生，提高小肝移植动物生存率。结果将有助于合理、科学利用供肝资源，解决供肝匮乏及其导致的系列问题。