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Packed Lunch: Pete Coffey on stem cells and treating blindness

2 Feb, 2010
The human eye. Image credit: Kate Whitley, Wellcome Images

The human eye

The concept of stem cell treatments has risen to prominence over the last ten years, as the field continues to develop and scientists get closer to turning promise into reality. Perhaps one of the most alluring prospects is the use of stem cells to restore sight, and this is what Professor Pete Coffey came to talk about one lunchtime at Wellcome Collection.

Coffey is a scientist at the Institute of Ophthalmology at University College London. He is also Director of the London Project to Cure Blindness, an ambitious five-year project developing a stem cell therapy for Age-related Macular Degeneration (AMD) (as well as prevent blindness, restore sight and improve sufferers’ quality of life… by 2012).

AMD is a leading cause of blindness in over 60s in the West – 25 per cent of over 60s in the UK have some degree of visual loss due to AMD and this is expected to triple in the next 10-20 years. Coffey’s research looks to cure this by using embryonic stem cells to replace the defective cells causing the disease.

AMD is a failure of cells in the macular region of the eye – that is, the part that allows you to see things at the highest resolution, picking out the details that allow you to read and recognise faces.

But the problem comes not when the photosensitive cells themselves fail, but when the housekeeper cells behind them – the retinal support cells, or retinal pigment epithelium –degenerate. These cells are vital in getting rid of the debris and chemical waste created by the neural retina, but when they no longer refresh the debris builds up. This results in distortions and blurred vision.

The good news is that the support cells are only a single layer thick, making them a relatively simple target for stem cell therapy. The eye also has the advantage of being partially immuno-privileged – that is, it doesn’t lead to the kind of transplant rejection you get in, say, heart transplants.

Coffey hopes to turn embryonic stem cells into new support cells in the laboratory and reintroduce them to the eye in a simple 45 minute operation. This would be a tremendous breakthrough as, until recently, AMD was largely untreatable – and even today 90 per cent of cases still are.

The breakthrough thus far is curing, at least temporarily, the Royal College of Surgeons rat (yes, that really is what it is called). Coffey’s team have successfully turned stem cells into retinal support cells and transplanted these into the rat, restoring its sight.

It was a major advance, but there are still major obstacles. The support cells will need to be produced to a clinical standard (the last thing anyone would want is or the cell to turn into a tumour). Then there is perfecting the surgical procedure, as well as regulating the treatment. But the research is progressing at a breakneck pace – the team has already scaled up their work to a pig model (pig eyes are the same size as humans) and hopes to conduct their first clinical trial next year (2011).

What’s exciting about stem cell therapy, says Coffey, is the fundamental shift in thinking that it could bring to medicine. “Up until now, most medicine has been about maintaining what we have, making sure something doesn’t get worse. Stem cell therapies offer the chance to get them back to what they were. And that’s better than pure maintenance.”

Listen to the whole talk:

You can also download the talk as a podcast on the Wellcome Collection website.

Packed Lunch is a regular series of science talks featuring local(ish) researchers talking about their research, motivations, inspirations and what it’s like to be a scientist. Visit the Wellcome Collection website for more info. You can also listen to past talks in the archive.

Image credit: Wellcome Images and Kate Whitley

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