Soltys Kyle A, Setoyama Kentaro, Tafaleng Edgar N, Soto Gutiérrez Alejandro, Fong Jason, Fukumitsu Ken, Nishikawa Taichiro, Nagaya Masaki, Sada Rachel, Haberman Kimberly, Gramignoli Roberto, Dorko Kenneth, Tahan Veysel, Dreyzin Alexandra, Baskin Kevin, Crowley John J, Quader Mubina A, Deutsch Melvin, Ashokkumar Chethan, Shneider Benjamin L, Squires Robert H, Ranganathan Sarangarajan, Reyes-Mugica Miguel, Dobrowolski Steven F, Mazariegos George, Elango Rajavel, Stolz Donna B, Strom Stephen C, Vockley Gerard, Roy-Chowdhury Jayanta, Cascalho Marilia, Guha Chandan, Sindhi Rakesh, Platt Jeffrey L, Fox Ira J
Thomas E. Starzl Transplant Institute, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, United States.
Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States.
J Hepatol. 2017 May;66(5):987-1000. doi: 10.1016/j.jhep.2016.12.017. Epub 2016 Dec 24.
BACKGROUND & AIMS: Hepatocyte transplantation partially corrects genetic disorders and has been associated anecdotally with reversal of acute liver failure. Monitoring for graft function and rejection has been difficult, and has contributed to limited graft survival. Here we aimed to use preparative liver-directed radiation therapy, and continuous monitoring for possible rejection in an attempt to overcome these limitations.
Preparative hepatic irradiation was examined in non-human primates as a strategy to improve engraftment of donor hepatocytes, and was then applied in human subjects. T cell immune monitoring was also examined in human subjects to assess adequacy of immunosuppression.
Porcine hepatocyte transplants engrafted and expanded to comprise up to 15% of irradiated segments in immunosuppressed monkeys preconditioned with 10Gy liver-directed irradiation. Two patients with urea cycle deficiencies had early graft loss following hepatocyte transplantation; retrospective immune monitoring suggested the need for additional immunosuppression. Preparative radiation, anti-lymphocyte induction, and frequent immune monitoring were instituted for hepatocyte transplantation in a 27year old female with classical phenylketonuria. Post-transplant liver biopsies demonstrated multiple small clusters of transplanted cells, multiple mitoses, and Ki67 hepatocytes. Mean peripheral blood phenylalanine (PHE) level fell from pre-transplant levels of 1343±48μM (normal 30-119μM) to 854±25μM (treatment goal ≤360μM) after transplant (36% decrease; p<0.0001), despite transplantation of only half the target number of donor hepatocytes. PHE levels remained below 900μM during supervised follow-up, but graft loss occurred after follow-up became inconsistent.
Radiation preconditioning and serial rejection risk assessment may produce better engraftment and long-term survival of transplanted hepatocytes. Hepatocyte xenografts engraft for a period of months in non-human primates and may provide effective therapy for patients with acute liver failure.
Hepatocyte transplantation can potentially be used to treat genetic liver disorders but its application in clinical practice has been impeded by inefficient hepatocyte engraftment and the inability to monitor rejection of transplanted liver cells. In this study, we first show in non-human primates that pretreatment of the host liver with radiation improves the engraftment of transplanted liver cells. We then used this knowledge in a series of clinical hepatocyte transplants in patients with genetic liver disorders to show that radiation pretreatment and rejection risk monitoring are safe and, if optimized, could improve engraftment and long-term survival of transplanted hepatocytes in patients.
肝细胞移植可部分纠正遗传性疾病，且有个别案例显示其与急性肝衰竭的逆转有关。监测移植物功能和排斥反应一直很困难，这导致移植物存活受限。我们旨在采用肝脏定向预处理放疗，并持续监测可能的排斥反应，以克服这些限制。
在非人灵长类动物中研究肝脏定向预处理放疗作为改善供体肝细胞植入的策略，随后应用于人类受试者。还在人类受试者中检测T细胞免疫监测，以评估免疫抑制的充分性。
在接受10Gy肝脏定向照射预处理的免疫抑制猴中，猪肝细胞移植成功植入并扩增，在照射节段中占比高达15%。两名尿素循环缺陷患者在肝细胞移植后早期出现移植物丢失；回顾性免疫监测提示需要加强免疫抑制。对一名患有经典苯丙酮尿症的27岁女性进行肝细胞移植时，采用了预处理放疗、抗淋巴细胞诱导治疗及频繁的免疫监测。移植后肝脏活检显示有多个小簇的移植细胞、多个有丝分裂象及Ki67阳性肝细胞。尽管移植的供体肝细胞数量仅为目标数量的一半，但移植后外周血苯丙氨酸（PHE）平均水平从移植前的1343±48μM（正常范围30 - 119μM）降至854±25μM（治疗目标≤360μM）（降低36%；p<0.0001）。在监督随访期间，PHE水平一直低于900μM，但随访不规律后出现移植物丢失。
放疗预处理和系列排斥反应风险评估可能使移植肝细胞获得更好的植入及长期存活。肝细胞异种移植在非人灵长类动物中可存活数月，可能为急性肝衰竭患者提供有效治疗。
肝细胞移植有可能用于治疗遗传性肝脏疾病，但其在临床实践中的应用因肝细胞植入效率低下及无法监测移植肝细胞的排斥反应而受到阻碍。在本研究中，我们首先在非人灵长类动物中表明，对宿主肝脏进行放疗预处理可改善移植肝细胞的植入。然后我们将这一知识应用于一系列遗传性肝脏疾病患者的临床肝细胞移植中，结果表明放疗预处理和排斥反应风险监测是安全的，并且如果优化，可改善患者移植肝细胞的植入及长期存活。
