Sunday, February 2, 2014

Cooking Up Stem Cells: Implications for Human Enhancement and Ageing

Every once in the while a research paper is published that really astounds you. Such is the recent pair of NATURE papers from Obokata et al (1).  What is described is an extremely simple way to convert mature differentiated cells to stem cells by exposure to stresses such as low pH. This process is called Stimulus-Triggered Acquisition of Pluripotency (STAP). The STAP cells seem to be able to contribute to all tissues in chimeric mice and to be passed through the germ line, the hallmark of truly pluripotent stem cells. Interestingly, the STAP cells can contribute to both embryonic and placental tissue. This is unlike iPS cells, whose pluripotency is induced by expression of a small set of transcription factors, and which can only contribute to embryonic tissue.

Assuming that it can be extended to human cells, this amazing result has numerous potential implications.  First of all it calls into question the much-touted concept of cancer stem cells. Perhaps these are simply cells that have been converted to stemness by the harsh tumor environment (low pH, low O2). Second, by making stem cell production far easier the STAP approach will hasten implementation of stem cell based therapies in various diseases. But perhaps most interesting consequence may be in the nascent field of human enhancement. By virtue of being able to generate large numbers of stem cells from an individual’s own cells it may be possible to retard the accumulation of senescent cells that have been implicated as a key factor in the tissue degeneration that accompanies increasing age (2).  So are STAP cells the fountain of youth? We shall see. 

(2) Baker, D.J., Wijshake, T., Tchkonia, T., LeBrasseur, N.K., Childs, B.G., van de Sluis, B., Kirkland, J.L. and van Deursen, J.M. (2011) Clearance of p16Ink4a-positive senescent cells delays ageing-associated disorders. Nature, 479, 232-236

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