title: Human induced pluripotent stem cells on autologous feeders.
abstract: BACKGROUND
  For therapeutic usage of induced Pluripotent Stem (iPS) cells, to accomplish xeno-free culture is critical. Previous reports have shown that human embryonic stem (ES) cells can be maintained in feeder-free condition. However, absence of feeder cells can be a hostile environment for pluripotent cells and often results in karyotype abnormalities. Instead of animal feeders, human fibroblasts can be used as feeder cells of human ES cells. However, one still has to be concerned about the existence of unidentified pathogens, such as viruses and prions in these non-autologous feeders.
  
  
  RESULTS
  This report demonstrates that human induced Pluripotent Stem (iPS) cells can be established and maintained on isogenic parental feeder cells. We tested four independent human skin fibroblasts for the potential to maintain self-renewal of iPS cells. All the fibroblasts tested, as well as their conditioned medium, were capable of maintaining the undifferentiated state and normal karyotypes of iPS cells. Furthermore, human iPS cells can be generated on isogenic parental fibroblasts as feeders. These iPS cells carried on proliferation over 19 passages with undifferentiated morphologies. They expressed undifferentiated pluripotent cell markers, and could differentiate into all three germ layers via embryoid body and teratoma formation.
  
  
  CONCLUSIONS
  These results suggest that autologous fibroblasts can be not only a source for iPS cells but also be feeder layers. Our results provide a possibility to solve the dilemma by using isogenic fibroblasts as feeder layers of iPS cells. This is an important step toward the establishment of clinical grade iPS cells.
authors: Center for iPS cell Research and Application, Institute for Integrated Cell-Material Sciences, Kyoto University, Kyoto, Japan. takahash@cira.kyoto-u.ac.jp
authors: Kazutoshi
authors: K
authors: Takahashi
authors: Megumi
authors: M
authors: Narita
authors: Midori
authors: M
authors: Yokura
authors: Tomoko
authors: T
authors: Ichisaka
authors: Shinya
authors: S
authors: Yamanaka
mesh_terms: D049109:Cell Proliferation; D020405:Dermis / Q000166:cytology; D005347:Fibroblasts / Q000166:cytology*; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000166:cytology*