Team makes breakthrough in retinal cell transplantation
A Taiwanese research team has developed a new technique for retinal cell transplantation that could one day result in more effective treatments for an incurable eye disease that can lead to blindness, the team’s leader said Monday.
Chiou Shih-hwa, the director of the Division of Basic Research under Taipei Veterans General Hospital’s Department of Medical Research and Education, said the method, which is currently being tested in pigs, could offer a new approach to dealing with age-related macular degeneration (AMD).
The disease affects more than 200,000 people in Taiwan and is the top cause of blindness among people aged 50 and above in the West.
Drug treatments involving injections into the eye have been used for years to stem the advance of the disease, Chiou said, but they have their limitations.
Scientists are now trying a newer approach — retinal cell transplantation — which is aimed at regenerating photoreceptor cells in the macula, a part of the retina that is critical for sharp vision, and the retinal pigmented epithelium (RPE), a layer of cells that protects and nourishes photoreceptor cells.
Chiou said a team in the United States has begun the second round of human clinical trials in transplanting embryonic stem cells in patients to deal with AMD, but the team’s method of injecting the cells into the retina has led to uneven results.
Chiou’s team has devised a way to generate induced pluripotent stem cells — cells can give rise to any other cell type in the body — from human blood and then arrange them on a customized stent no thicker than a human hair that is inserted under the retina.
The stent serves as a monolayer RPE, ensuring that the cells are delivered as uniformly as possible and enabling them to cover a wider area in the retina to improve the chances of success, Chiou said.
“It’s like trying to repair a road. With injections, you can only fill in potholes and the thickness may not be uniform. By inserting this layer, we are laying down a smooth road that may give better results,” Chiou said.
Another potential advantage of the new technology, according to Chiou, is that it can be customized to the patient’s retina.
The stents have already been successfully inserted into the eyes of pigs, with the animals’ eye functions remaining normal and the cells remaining alive, Chiou said, and the next step will be to test the method in animals for efficacy.
Should those trials go smoothly, the team would then apply to use the process in clinical trials on humans, Chiou said, hoping that such trials could begin in two to three years.