This week is AMD Awareness Week in Ireland, and during this week we are urging everyone over the age of 50 to avail of free testing nationwide for this prevalent yet often treatable condition.
A number of new treatments have been approved in the last ten years and undoubtedly have substantially improved quality of life for people living with age-related macular degeneration (AMD). However, there is still an unmet clinical need for new and more effective treatments. One of the most promising areas of investigation is stem cell research and a number of groups worldwide are making great strides in this area.
One of these groups led by Dr Masayo Takahashi of the RIKEN institute Japan took a massive leap forward last Friday, September 12, when a patient with AMD in her mid-70s underwent a two hour operation and had retinal pigment epithelium (RPE) cells made from stem cells surgically inserted into her retina. The fascinating and ground-breaking aspect of this clinical trial is that these RPE cells (which are the cells that become dysfunctional in AMD) were made from stem cells developed from the patient’s own skin cells. This type of stem cell is known as induced pluripotent stem cells or iPS for short.
In iPS technology, a small skin sample is taken from the patient. The cells are then manipulated by adding a number of factors and reprogrammed to behave like embryonic stem cells, therefore gaining the potential to develop into any cell in the body. Scientists can manipulate these cells’ ultimate fate in the laboratory and generate RPE cells that are indistinguishable from cells that occur naturally and transplant them back into the patient.
Other groups are currently conducting stem cell trials for AMD in the UK and USA; however the notable aspect of this work is the use of iPS rather than cells of embryonic origin. This technology therefore eliminates many of the ethical issues surrounding this exciting area. Also, as the cells originate from the person themselves, there is theoretically no chance of rejection.
As this is an extremely new technology and the first study of its kind to be conducted in man, this trial will progress slowly and it is anticipated that the next patient will not undergo transplantation for at least eight weeks. This group are truly reaching into the unknown, and this gap is crucial in order to monitor the first patient for any bad reaction to the transplanted cells before moving onto the next five individuals.
Unlike other current studies, the researchers are targeting the wet form of AMD which is more debilitating rather than the more common dry form. This study also transplants ‘sheets’ of RPE cells rather than cells in a suspension, which is likely to produce more optimal results and this more closely mimics the natural occurrence of RPE cells layered in the retina.
Stem cell technology holds great potential for a number of degenerative retinal diseases to replace retinal cells that have already died due to degeneration. RPE cells provide nourishment and support the photoreceptor cells, but are not themselves responsible for ‘seeing’ and it is not anticipated that vision will be restored with this clinical trial. Rather, it is hoped that replacement of RPE cells will help the retina function better, prevent further vision loss and help nourish surviving retinal cells.
The ultimate aim of restoring vision by transplanting stem cell derived photoreceptor cells is at an earlier stage of research, but a number of recent animal studies – including by our Chief Scientific Advisor Prof Robin Ali – have shown the potential to restore function in the eye, which may pave the way for human studies in the future.
We, along with the international retina community will be monitoring the progress of this momentous trial carefully. It is heartening to see many stem cell approaches reaching clinical trial phase and we will report on any developments and announcements from all of these trials in the future.
For more information, read Nature magazine’s article about the trial.
You can download a copy of our AMD Information Booklet here or contact us on 01 6789 004 or firstname.lastname@example.org if you would like to request a copy by post.