CD 133+ stem cells for the treatment of end stage liver disease.

Previous studies have shown that bone marrow (BM) cells contribute to liver regeneration after tissue injury. The main objective of the present study was to evaluate the feasibility and the safety of the purification and intrahepatic reinfusion of increasing numbers of autologous BM-derived G-CSF-mobilized CD133+ stem cells (SCs) in patients with end-stage liver disease (ESLD). For this purpose, G-CSF at 7.5 µg/Kg/b.i.d. is administered subcutaneously (sc) from day 1 until the completion of peripheral blood stem cells (PBSC) collection. Collection of PBSC begin on day + 5 only if the concentration of CD133+ cells is > 8/µL. CliniMacs device is used for the positive selection of CD133+ SCs (under GMP conditions) from PB of mobilized standard-volume leukapheresis. At least 4 weeks after SC mobilization, collection and cryopreservation, highly purified autologous G-CSF-mobilized CD133+ cells are re-infused through the hepatic artery by transfemoral or transbrachial arteriography. CD133+ cells are administered to patients starting from 5x104/Kg patient’s body weight and increased every 3 patients up to 1x106/kg. G-CSF at 5µg/Kg/day is administered sc for 3 days after the reinfusion of SCs for their expansion and to induce a selective proliferative advantage of reinfused cells in vivo. Biological assays (phenotype of circulating SCs, clonogenic assays, serum cytokines) were done during the mobilization and re-infusion phases together with the phenotypic characterization of the isolated CD133+ SCs. The clinical trial is ongoing. Up to date, 9 patients have been successfully mobilized with G-CSF and highly purified autologous CD133+ SCs have been re-infused in 7 cases. Based on preliminary data, we suggest the feasibility and safety of intrahepatic reinfusion of highly purified CD133+ stem cells in patients with ESLD. Biological studies show that: 1) circulating hematopoietic and endothelial progenitors are increased after G-CSF treatment; 2) highly purified CD133+ cells express hematopoietic and endothelial markers; 3) serum concentration of HGF, SDF-1, VEGF and MMP9 and clonogenic capability of hematopoietic progenitors are increased during the mobilization and re-infusion phases; 4) clonogenic potential of endothelial progenitors shows variable expression.