Monday, September 23, 2013

Stem Cells Offer New Hope For The Blind

If the last half of the 20th century was the era of computer technology, then the first half of the 21st century may well be the era of biotechnology. The pace of progress in the field is becoming astonishing, with new achievements appearing nearly every day. For instance, consider the sequencing of the human genome. According to the National Human Genome Research Institute, at the time that the human genome was first sequenced, the cost of sequencing an individual’s DNA lay somewhere between $10 million and $100 million. Now, that cost is less than $10,000 and heading toward $1000 – that makes it economical to sequence a patient’s entire DNA to identify personalized treatments for diseases such as cancer.


Image source: http://www.med.upenn.edu/cores/images/dna_sequencing.png

Another area with enormous promise – although highly controversial – is stem cell research. Now, it appears that advances in this field are offering the possibility of a cure for certain types of blindness. Scientists have managed to grow light-sensitive retina cells in the lab, and have managed to integrate these back into the retinas of blind mice. Not only did they develop normally once they were placed into the eyes of a mouse, but – and this is crucial – they started to create neural connections back to the mouse’s brain.

While this work, carried out at University College London’s Institute of Ophthalmology, is still in its early stages, researchers are hopeful that it will lead to a cure for conditions such as age-related macular degeneration, retinitis pigmentosa, diabetic blindness and other conditions which affect the human retina. Apparently, it will be at least five years before human trials start, but researchers are confident that they will happen. Perhaps someday we will be able to go to an eye institute such as benjamineye.com and have our retinas treated in much the same way as we have laser eye treatment for myopia today.

This is not the first major advance using stem cells to regenerate retinas. Back in 2011, a team in Japan managed to grow new retina tissue from mouse stem cells, not just individual light-sensing cells. In fact, they were surprised how easily the cultured stem cells organized themselves into a structure reminiscent of an embryonic eye. They were able to create a three-dimensional layered tissue that – in many important ways – was identical to natural retinal tissue. However, the importance of the latest breakthrough is that it offers the possibility of repairing an existing retina, rather than the almost impossible task of replacing a retina and wiring it back correctly to the brain.


Image source: http://media.smithsonianmag.com/images/gene-therapy-Alisha-Bacoccini-blindness-631.jpg

Of course, stem cell research is controversial, mainly because it has used cells from embryos – which may be acceptable for animal experimentation, but raises significant ethical issues when it comes to humans. While these advances in mice also used embryonic stem cells, there has been progress over the last few years with adult stem cells – stem cells that are created by treating normal adult cells so that they return to a more potent state. In fact, this approach may be preferable for real therapies, as the patient’s own tissues can be used, avoiding the problem of rejection typically seen when foreign tissues are transplanted.

3 comments:

  1. While progress is being made using iPS cells, one company, Advanced Cell Technology, using RPE derived from hESCs (done without destroying the embryo) has already advanced into human clinical trials, with at least 30 patients safely treated to date in trials for Stargardt's disease and dry AMD, and with improved vision in almost all of the patients.

    In fact, one dry AMD patient has gone from 20/400 vision to 20/40 (eligible to obtain a drivers license in most states). To read about this, take a look at my writeup: http://tinyurl.com/StemCellUpdate25

    Irv Arons

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  2. Advanced Cell Technology's dry-AMD/SMD phase I/II trial data will be peer-reviewed, and publication should be press-released soon. From what I've heard on most recent conference call, the data is "tantalizing".

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  3. I should also note that instead of waiting five years, there are currently 41 human clinical trials underway or completed, using stem cells and cell therapies, for treating 16 ophthalmic disorders. To review the companies/institutions involved, the applications under research, and the list of clinical trials, see http://tinyurl.com/StemCellTbls

    Irv Arons

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