Cell Stem Cell Articles
In this issue of Cell Stem Cell, Staerk et al. (2010), Seki et al. (2010),Staerk et al. (2010), Seki et al. (2010), and Loh et al. (2010) each describe the derivation of human iPSCs from peripheral blood. Although seemingly incremental, this advance brings the stem cell field an important step closer to eventual clinical use.
we have developed a minimally invasive method for hiPSC generation without genomic integration that uses low numbers of hTDCTCs from peripheral blood. This method has advantages for research into stem cell reprogramming, TCR rearrangement, immunologic disorders, and the development of genetic markers for future applications of regenerative medicine. TiPSCs may well be relatively easy to use in a clinical setting.
Our study demonstrates that peripheral blood can be utilized as an easily accessible source of patient tissue for reprogramming without the need to extensively maintain cell cultures prior to reprogramming experiments. This is an important step to make the iPSC technology more broadly applicable
Because taking blood is safe, fast and efficient compared to current stem cell harvesting methods, some of which include biopsies and pretreatments with drugs, researchers hope that blood-derived stem cells could one day be used to study and treat diseases — though major safety hurdles remain.
The findings “represent a huge and important progression in the field,” stem cell biologist Shinya Yamanaka of Kyoto University in Japan and the Gladstone Institute of Cardiovascular Disease in San Francisco, California writes in a commentary appearing in the same issue of the journal.
Three research groups used similar methods to prod certain immune cells in human blood to become induced pluripotent stem cells. Because they are reprogrammed adult cells, these stem cells share many of the same regenerative abilities as true embryonic stem cells but may not have as much versatility in the kinds of mature cells they can become. But induced pluripotent cells are harvested from adults and so don’t face the same ethical mires posed by embryo-derived stem cells. And as techniques for manipulating induced pluripotent cells improve, some researchers think they may be just as useful.
The new studies accomplished the reprogramming feat by using viruses to deliver a four-gene cocktail that reverts the cells to a naïve state in which any developmental path is open. In theory at least, these induced pluripotent stem cells could go on to form neurons in the brain, muscle cells in the leg or beating heart cells.
Scientists’ manipulations turned the stem cells in the new studies into several types of mature blood cells, including infection-fighting T cells. What’s more, all the groups showed that a batch of the stem cells implanted into mice developed into the three main types of progenitor cells found in human embryos. In embryos, these progenitor cells give rise to different tissues.