Our goal is to realize new strategies of regenerative medicine for untreatable liver diseases based on transplantation of human biliary tree stem cells (hBTSCs). The central part of the project is a controlled, randomized clinical trial (RCT) in which we will evaluate feasibility, safety and efficacy of a protocol of cell therapy based on transplantation, via hepatic artery infusion, of freshly isolated hBTSCs into patients with advanced liver cirrhosis. In parallel with the RCT, and to improve the benefits of hBTSC transplantation, we propose preclinical studies aimed to: i) assess if cryopreserved hBTSCs are also effective; ii)improve liver engraftment of transplanted cells; iv) identify additional subpopulations of biliary tree stem cells suitable for clinical programs. The project, presented at the call H2020-PHC-2015-single-stage_RTD (Funding scheme: Research and Innovation action, Proposal number: 681011, Activity: PHC-15-2015) received an evaluation of excellence (Total score: 12.00 (Threshold: 12). As part of the project presented at H2020-PHC-2015, the specific objectives of this application are: Clinical studies: to start the clinical trial aimed to demonstrate that administration via hepatic artery of hBTSCs in patients with advanced cirrhosis is feasible, safe and determines a clinically relevant improvement of liver function. Pre-clinical studies: specific objectives: 1. to assess serum-free, defined cryopreservation conditions for fetal hBTSCs with the final purpose to generate a cell bank helping the treatment of patients, the distribution and commercialization of the cell product. 2. to identify new human tissues as sources of cells similar to hBTSCs. To this purpose we have preliminary data showing how Brunner glands in the duodenal wall (peri-ampullar region) contain cells with similar phenopypic and genotypic traits with respect to hBTSCs. Positive results could give us an additional cell source to be used for the cell therapy of liver diseases.
Our proposal could furnish important advances in the treatment of decompensated cirrhosis, a clinical condition currently lacking effective treatments. The concept beyond the proposal is that hBTSCs are able to engraft into the liver, differentiate into mature liver cells, hepatocytes and/or cholangiocytes, and improve liver functions, thus contributing to the improvement of quality of life and, finally, the overall survival. The cell therapy we are proposing could also represent a bridge for organ transplantation, allowing downstaging of the disease. Our cell product could overcome current criticisms of cell therapies for terminal liver diseases or genetic/metabolic liver diseases for the following reasons: i) fetal tissue-derived hBTSCs can be easily isolated from tissues that are largely available since each year approx.10,000 therapeutic abortions are performed in Italy (and similarly elsewhere in some countries in Europe); ii) hBTSCs isolation can be carried out in less than 3 hours with a yield of 50-80 million cells from each fetal tissue (sufficient cells for treatment of a patient); iii) fetal hBTSCs are resistant to ischemia and, in preliminary experiments, also to cryopreservation; iv) fetal hBTSCs display indefinite self-renewal and robust differentiative capacities avoiding unnecessary transplantation of large numbers of cells as occurs with adult hepatocyte transplantation; v) the procedure of hBTSC infusion via hepatic artery is minimally invasive and safe. Indeed, our interventional radiology unit carries out, without adverse events, approx. 500 procedures/year of hepatic artery cannulation in cirrhotic patients, with different diagnostic or therapeutic indications; vi) the procedure can be repeated in the same patient if the resulting benefits are only transitory; vii) transplanted patients do not require immunosuppression due to the minimal or null immunogenicity of hBTSCs as demonstrated by our preclinical and clinical observations; viii) the procedure has a high probability of being effective for other liver diseases such as chronic progressive cholestatic and genetic/metabolic liver diseases. Our objective is to demonstrate that: a) the administration of hBTSCs via hepatic artery is minimally invasive, feasible, safe and effective. This would represent a milestone in the management of decompensated cirrhosis and could open a new therapeutic window on this disease which, at the terminal stage, has negligible chances for treatment; b) that cryopreserved hBTSCs can be used and, therefore, facilitate the generation of a cell bank. This would enable world-wide exportation of the cells, launching the cell product for use in patients with advanced liver diseases. Innovation potential of the proposal: We are proposing an innovative treatment for end-stage liver disease that could improve survival and quality of life of these patients. The innovation potential is based on: i) transplantation of hBTSCs that are normally involved in liver repair but that are impaired in their regeneration potential by the long-lasting inflammatory milieu characterizing liver cirrhosis; ii) a novel strategy of cryopreservation of hBTSCs that will help in the generation of a cell bank as well as in the exploitation of the cell product and of our therapeutic strategy; iii) the use of methodologies and procedures performed in GMP conditions that allow a rapid translation into the clinic; iv) additional subpopulations of hBTSCs to be used in clinical programs. In the market, the only cell types available for cell therapy of liver diseases are cryopreserved adult human hepatocytes that are well known to have poor viability and functioning on thawing and negligible proliferation capacity. However, a number of different studies and meta-analyses demonstrated the scarce or null efficacy of adult cryopreserved hepatocytes in the treatment of liver diseases. There are two U.S. patents (with many derivative international patents) on hBTSCs, were we are involved as inventors. In the case of positive findings of planned clinical trail , we will plan a larger prospective randomized controlled multi-center study. Due to the full replacement of liver functions guaranteed by the engraftment, regeneration and differentiation of transplanted hBTSCs, it will be possible to recover more functions of the human liver, thus reducing complications and deaths. Specifically, by ensuring the improvement of liver function, of reducing ascites recurrence and hepatic encephalopathy, cell therapy with hBTSCs will reduce the necessity of hospitalization and the demand for drugs (albumin, diuretics), and will ameliorate the quality of life of these patients. In addition, the cell therapy with hBTSCs could allow a higher number of patients to be maintained on the waiting list for transplantation or to be inserted on the list (down staging), thus increasing the number of patients that may benefit from organ transplantation.