Pioneering stem cell treatment improves vision in patients with dry macular degeneration.
A pioneering clinical trial in humans has shown that a new experimental treatment using stem cells can not only halt, but potentially reverse some of the vision loss caused by age-related macular degeneration (AMD) in its dry form, the most common among older adults.
Dry macular degeneration slowly and progressively destroys central vision, which is essential for tasks such as recognizing faces, reading or driving.
Currently available treatments can only slow the progression of the disease or partially compensate for visual loss, but do not recover damaged retinal tissue, but in this new study, researchers tested for the first time in humans a stem cell transplant designed to replace retinal pigment epithelium (RPE) cells, which are fundamental for the functioning of photoreceptors.
In the November 6 study at Cell Stem Cell, researchers analyzed 18 potential candidates and ended up including six volunteers, ages 71 to 86, all with advanced dry AMD. Three had very impaired vision, with visual acuity between 20/200 and 20/800, that is, at most they could only read the largest letter in the classic Snellen chart. The remaining three had acuity between 20/70 and 20/200.
Unlike the wet form of the disease, which progresses more quickly, dry AMD results from deposits of fats and proteins that, over time, destroy RPE cells and impair support for light-sensitive cells. The tested strategy involves transplanting new RPE cells derived from stem cells, produced from material from an eye bank.
Each participant received a relatively low dose of 50,000 RPE stem cells, administered via a single injection under the retina, in the superior temporal region of the macula, in each patient’s most affected eye. One year after the procedure, the results were surprising.
Firstly, the treatment showed a favorable safety profile: no tumors, signs of toxicity or immunological problems associated with the transplanted cells were observed. The complications recorded were those usual in eye surgeries of this type and not directly related to stem cells.
Even more impressive were the signs of visual benefit. All patients experienced an improvement in vision in the treated eye which was not observed in the non-interventional eye, suggesting that the effect is linked to the transplant. Among the three participants with worse initial vision, the average improvement corresponded to the ability to read 21 more letters on the Snellen chart after one year.
According to Rajesh Rao, physician and ophthalmologist at Michigan Medicine, responsible for the study, the team was satisfied with the safety data, but surprised by the size of the visual gain, especially in the most severely affected patients. This level of improvement has never previously been observed in patients with advanced dry AMD.
The trial now continues with the evaluation of higher doses of 150,000 and 250,000 cells, to determine whether it is possible to increase the benefit while maintaining safety. If the results are confirmed in later stages, this type of transplant could be the future of a new therapeutic option for millions of people with dry macular degeneration.
