Nature News has a fascinating article on induction of pluripotent stem cells by means of genetic reprogramming. Typically, skin cells have been used for reprogramming experiments. Cells called fibroblasts, which are prevalent in skin and help heal the skin when injured, have been the cell of choice for induced pluripotent stem cell (iPSC) production.
Recently, fat cells and pigmented skin cells appear to produce iPSCs much more efficiently and quickly. Reprogramming procedures with skin fibroblasts are rather inefficient and slow. Reprogramming human skin cells takes about a month for 1 in 10,000 fibroblasts to form iPSCs. Other cell types can do the job besides fibroblasts. For example blood, hair, bone marrow, and neural stem cells can be converted into iPSCs, but their conversion rate is not any better than that of skin fibroblasts. However, foreskin fibroblasts from a baby are better at making iPSCs (see Aasen, T. et al. Nat. Biotechnol. 26, 1276-1284), but this is hardly a good source of cells for adults.
Is there are better way? Apparently there is. Joseph Wu and Michael Langaker at Stanford University School of Medicine in California have converted fat tissue into iPSCs, and it took them only two days to acquire enough material for reprogramming. Compare that to about a month of biopsies to get enough fibroblasts. Additionally, cellular reprogramming of fat cells took only two more weeks and was 20-times more efficient than fibroblast reprogramming. By using fat cells, they were able to reduce the time required for the procedure by six to eight weeks (Sun, N. et al. Proc. Natl. Acad. Sci. USA, doi:10.1073/pnas.0908450106). Likewise, Konrad Hochedlinger and his co-workers at the Massachusetts General Hospital in Boston reprogrammed melanocytes, the skin cells that produce pigmented skin. Melanocytes undergo reprogramming after just 10 days and with five-fold greater success rates compared with fibroblasts (Utikal, J., Maherali, N., Kulalert, W. & Hochedlinger, K. J. Cell Sci., doi:10.1242/jcs.054783).
These findings suggest that making iPSCs is easier than previously thought. The therapeutic uses of iPSCs just became even more attractive.