Transplantation of Allogenous iPS Cells


Regenerative Medicine Coming to Enter into Practical Phase



Next years, four Japanese medical institutes - RIKEN (the Institute of Physical and Chemical Research), CiRA (Center for iPS Research and Application, Kyoto University), Kobe City Medical Center General Hospital, and Osaka University - will conduct clinical research for autoplantation and allotransplantation of retinal tissues made from iPS cells generated from autogenic tissues and allogeneic tissues for patients with exudative age-related macular degeneration that causes their field of view to distort and confirm safety of whether immunorejection occurs in the allograft tissues and of whether tumorigenesis in both the allograft tissues and autograft tissues.


Image:  iPS cells (Credit: CiRa)


These institutes will make retinal pigment epithelial cells from autogenous and allogenous iPS cells, form autograft cells and allograft cells in a sheet shape and in a suspension shape, and transplant the these four types of grafts into subjects.  These institutes will conduct the clinical research for five subjects per each type of these grafts.  CiRA has stocked allogenous iPS cells generated from tissues harvested from persons whose human leukocyte antigen types match those of many persons.  In the forthcoming clinical research, allogenous iPS cells stocked in CiRA will be used.    

In the first case of the clinical research that used autogenous iPS cells, after the subject agreed with the transplantation surgery until he underwent the surgery, it took about 11 months.  By contrast, in the forthcoming clinical research, since retinal pigment epithelial cells made from allogenous iPS cells whose human leukocyte antigen type match that of subjects are used, the waiting time for the surgery will become short.  In addition, since immunosuppression unlikely occurs in the allograft cells, after the transplantation surgery, the subjects would not need to take any immunosuppressant.  As a result, the cost of the transplantation surgery per subject in the forthcoming clinical research may be reduced to a fraction of the cost of the transplantation surgery in the former clinical research.  Moreover, when the graft cells in the suspension form is used for the transplantation surgery, it could become relatively easy.      


The former clinical research for the transplantation surgery of retinal pigment epithelial cells made from iPS cells was conducted for a subject with exudative age-related macular degeneration in September 2014 as the first case in the world.  After the transplantation surgery, the subject has a good prognosis.  The second subject for the transplantation surgery in the forgoing clinical research was suspended to undergo the transplantation surgery in June 2015 because genes of iPS cells of the patent had mutations.