Conference Proceeding

25 years in Isolation and Clinical Transplantation of Human Hepatocytes

Dr.Roberto Gramignoli,
Department of Laboratory Medicine, Karolinska Institute, Sweden

Hepatocyte transplantation (HTx) has been gaining acceptance for the treatment of liver diseases. Our laboratory has always been in the front line in the translation of HTx technology from bench to clinic. However, significant obstacles have been identified during last years, and several solutions have been proposed. The obstacles of significance include the limited number and quality of liver tissues as a cell source, the lack of clinical grade reagents, quality control evaluation of hepatocytes prior to transplant, hypothermic storage of cells prior to transplant, preconditioning treatments to enhance engraftment and proliferation of donor cells, tracking or monitoring cells after transplantation and the optimal immunosuppression protocols for transplant recipients. Our 20 years’ experience in more than 2,000 human liver cell isolations allowed us to standardize reagents and procedures in accordance with current Good Manufacturing Practice (cGMP), and design rapid and sensitive functional assays to insure that cells for transplant function adequately. Human hepatocyte suspension has been validated not only on tissues rejected from organ donation, but also on liver resections performed for multiple clinical reasons, explanted inborn error of metabolism tissues (proved useful as cell source for clinical purposes), and fetal liver tissues at different gestational ages. As part of clinical program, our functional assays formed the basis for recipient’s need match criteria in hepatocytes transplant programs. A large spectrum of primary cells has been analyzed to determine a normal range of activities from isolated cells of different origin. Data collected on recovery, viability, apoptosis, in vitro adhesion and multiple hepatic functions including basal and induced cytochrome P450 (CYP) activities, phase II conjugation and ammonia metabolism allowed us to enlarge the number of tissues and worked as quality control. In addition studies on short-term cold-storage as well as long-term cryo-preservation have been performed and reviewed. However, the success of HTx programs is hampered by insufficient engraftment and long-term acceptance of cellular allografts. Insufficient engraftment that in recent years has been approaches by different clinical strategies aimed to provide selective growth advantage to the donor cells, such as partial hepatic resection, portal vein embolization and external beam radiation. All these approaches are in continued development, aimed to improve HTx therapy. Excluding acute liver failure patients, the observation that no metabolic disease patient has been completely cured of the long-term symptoms of their disease by HTx alone, indicates that continued improvements are required.

Published: 27 April 2017