In a joint research project with Osaka University and Ajinomoto Co., a Kyoto University research team led by Masato Nakagawa, a lecturer at CiRA, and Shinya Yamanaka, a professor at CiRA, has developed a new method for generation and maintenance culture of induced pluripotent stem cells or iPS cells that are suitable for use in cell transplantation therapy. Their findings have been published in Scientific Reports online on January 8 EST.

In order to use human iPS/ES cells in regenerative medicine, the cells must be prepared using methods compliant with GMP (Good Manufacturing Practice). However, the methods in use up till now have used feeder cells to culture iPS/ES cells, which involves complicated procedures, and have employed culture medium containing serum and numerous other animal-derived constituents, which made it difficult for them to comply with GMP. 

In the method reported in the paper, feeder cells were replaced with recombinant laminin 511-E8 fragments, which were developed by the research team of Professor Kiyotoshi Sekiguchi of Osaka University Institute for Protein Research and manufactured to GMP standard by Nippi, Inc. The cells were maintained in a culture medium free of animal-derived constituents (xeno-free) which was developed jointly with Ajinomoto. Using this method facilitates the handling of human iPS/ES cells and makes it possible to perform stable and long-term serial passage culture without generating chromosomal abnormalities. 

These iPS cells generated from human skin or blood cells with no use of feeder cells (feeder-free) and cultured in the xeno-free medium were transplanted into immunodeficient mice. Teratoma formation was observed and the cells were confirmed to be capable of differentiating into the cells of all three germ layers. The researchers also succeeded in inducing the iPS cells thus produced to differentiate into dopamine-producing cells, insulin-producing cells, and blood cells. 

These findings demonstrate that generation and maintenance culture of human iPS cells is possible using this newly developed feeder-free and xeno-free culture system. This method will not only make it possible to generate iPS cells of a quality ideally suited to cell transplantation into humans, but should also prove useful in areas such as drug discovery, toxicity testing, and disease modelling. 

iPS cells were successfully generated from each of fibroblast, blood cell (T cell and non-T cell) and umbilical cord blood cell lines.