Wednesday, August 26, 2009

Retinal cells from iPS cells… no need for embryos

Remember the excitement about ESC being used to create retinal cells? Big headlines amongst the excitable. Now, of course, the Aug. 24 edition of the Proceedings of the (US) National Academy of Sciences shows the creation of human retinal cells from the superior-in-every-way iPS cell derived from skin.


Says the University of Wisconsin-Madison School of Medicine scientist: "This is an important step forward for us, as it not only confirms that multiple retinal cells can be derived from human iPS cells using the Wisconsin approach, but also shows how similar the process is to normal human retinal development."


Here is the report in Science Daily:

Retina Cells Created From Skin-derived Stem Cells


"The Wisconsin team took cells from skin, turned them back into cells resembling embryonic stem cells, then triggered the development of retinal cell types.

"Because the group was successful using the iPS cells, they expect this advance to lead to studying retinal development in detail and treating conditions that are genetically linked. For example, skin from a patient with retinitis pigmentosa could be reprogrammed into iPS cells, then retina cells, which would allow researchers to screen large numbers of potential drugs for treating or curing the condition.

"The team had similar success in creating the multiple specialized types of retina cells from embryonic stem cells, underscoring the similarities between ES and iPS cells."


'Similarities' indeed between ES and iPS cells – they are functionally identical - but there are vital dissimilarities in the relative usefulness of iPS and ESC:

  • only iPS matches the patient, so only iPS is useful for genetic research and drug tailoring for that patient;
  • only iPS could (if any pluripotent cell is ever considered safe) be used in transplants of retinal cells without the need for immune suppression.
  • only the ugly science of ESC research involves strip-mining an embryonic human for its useful bits.


And as per our earlier Blog on the Big Deal about ESCs producing retinal cells:

  • For that matter, why use either ESC or iPS when you can use adult stem cells (ASC)? We already have reports of the capacity of ASCs to generate the same retinal cells generated by ESCs in this 'breaking news'. Again, there is not one but TWO huge clinical differences. ASCs, like iPS cells, match the patient – but ESCs are foreign. Further, ASCs alone are free from the tumour risk inherent in ESC / iPS cells. Which type of cell would you, the patient, prefer to have in the back of your eye?


Friday, August 21, 2009

This is the whole point: iPS cells shed light on a rare disease

Here is how it works, if you want to get specific cells from a patient to study their rare disease and test treatments on those cells. In this case, brain cells – without biopsying a bit of brain – in patients with FD (familial dysautonomia). And don't' forget, that is really the one serious use of iPS or ESC: researching a genetic disease and developing treatments. Talk of so-called direct cell therapies with ESC or iPS cells is just tall tales for journalists to help them sell papers; as we know, only adult stem cells are safe for use in direct cell therapy.


Meantime, back at the lab, Susan Slaugenhaupt, a neurologist at Massachusetts General Hospital, says this technology provides "the ability to examine disease-relevant cell types from patients" for the first time. "You can't get brains from patients and look at these cell types." They even find a promising response in vitro to one of their drugs.

And as the research article in Nature says today: "Our study illustrates the promise of iPSC technology for gaining new insights into human disease pathogenesis and treatment."


And that is the whole point. No ESC has ever given insight into a particular patient's disease, because you would have to clone that patient into his twin embryo first to get its stem cells (which has never been achieved). Why bother, when iPSC is doing the job?


Read today's MIT report at


Or look up the Nature article at doi:10.1038/nature08320