iPS cells for transplantation

Purpose of review The induced pluripotent stem (iPS) cells from patient's somatic cells could be a useful source for drug discovery and cell transplantation therapies. However, there are still several problems to be solved in terms of safety concerns. We herein summarize the current knowledge about iPS cells and the obstacles that must be overcome before the cells can be used for medical applications. Recent findings Recent progress has enabled us to generate integration-free iPS cells from noninvasive tissues. Several studies have also uncovered differences in iPS cells and ES cells in terms of gene expression, epigenetic modification, and differentiation potentials. Tissue origin affects the quality of iPS cells. However, in a rodent disease model, the transplantation of differentiated cells derived from iPS cells ameliorated their symptoms. Methods for gene correction and direct cell fate switching have also been reported. The successful generation of human leukocyte antigen (HLA)-typed iPS cells has been described. These findings should therefore facilitate the further application of iPS cells. Summary Human iPS cells are able to provide functional neuronal cells, blood cells, and retinal cells, which would be a useful source for transplantation. Although recent reports have shown that it may be possible to overcome several difficulties associated with iPS cells, further improvements are needed, not only regarding safety aspects, but also in quality, before they can be medically applied.