Preliminary results in the first two humans treated with retinal pigment epithelial (RPE) cells derived from human embryonic stem cells (hESCs) have just been published in The Lancet. One patient, aged 51, has Stargardt's disease (the most common form of macular degeneration in younger people) and the other, aged 78, has age-related MD.
The results show that the first two patients have shown no adverse effects, rejection or inflammation, and the cells are behaving exactly as hoped. Some additional patients have now been entered into the trial due to this initial demonstration of safety.
While this study is not primarily designed to look at visual outcomes, the first two patients have already shown some improvement in their vision. Before treatment, the Stargardt's patient was unable to read a single letter on a standard eye chart. After one month, she could read the top five letters on the chart, and also had improved colour and contrast perception. The MD patient was also able to read several more letters on the chart.
It must be stressed that these results are preliminary, with a very short follow-up. Many more patients will need to be tested with larger doses of implanted cells and much longer follow-up before this treatment can be made more widely available.
This study is being conducted in the USA, but has also just been expanded to the UK.
Stem Cell Research
Stem cells are master cells that can differentiate (change) into any of the hundreds of types of cells in the human body. In this initial study, a small quantity of differentiated RPE cells was implanted under the retina of these patients to assess the safety of this technique. The ultimate aim of this treatment is that the implanted RPE cells will survive, remain stable, and take the place of those cells that have died due to MD. RPE cells are critical to maintain the health of the photoreceptor cells in the retina which send light signals to the brain to be converted to an image.
18 February 2012