14 DAY TRIAL // Scientists with Boston, Massachusetts-based Advanced Cell Technology (ACT) are currently testing a new type of therapy that could help preserve vision in the visually-impaired and even reverse vision loss in people who are already blind. The company has already registered significant progress and is now in the stages of setting up tests on human patients.
The treatment is meant to address a common disorder called macular degeneration (MD). The disease is usually age-related, affecting older adults predominately. Its main symptom is damage to the retina, which leads to loss of vision in the macula, the center of the visual field. MD is one of the leading causes of blindness in people over the age of 50 around the world.
Since this disease affects only the macula, patients are usually left with some peripheral vision, just enough so that they are able to complete at least some basic activities on their own. In the most extreme cases, macular degeneration leads to total blindness, but not directly. Associated conditions, such as untreated glaucoma, are usually what causes a complete loss of vision, Technology Review reports.
Available treatments for MD currently include laser coagulation and medication that stops and reverses the growth of blood vessels underneath the retina (a characteristic of the so-called “wet” form of MD). What ACT is proposing is the first-ever therapy based on embryonic stem cells (ESC). The company says it is now ready to begin testing of its treatment method on humans.
Officials say that their ESC-based approach is targeted at patients with MD and Stargardt’s disease, which is an inherited form of progressive vision loss that usually affects children. A small-scale study has already been conducted, but its full conclusions have not yet been published. One patient fared particularly well, recovering vision after being declared legally blind.
The active element in the new therapy is a solution containing retinal pigment epithelium (RPE) cells, which ACT experts grow from ESC. Treating the two conditions involves the injection of 150 microliters of RPE solution under patients' retinas, where the cells boost the ability of light-sensitive receptors to capture and process incoming light.
The ACT experimental treatment is based on a discovery made by researcher Irina Klimanskaya, while working at Harvard University. The expert is now the director of stem-cell biology at ACT. She noticed that stem cells supplied with enough nutrients, but left to their own devices in lab cultures, tended to differentiate into multiple types of adult cells.
Oftentimes, the stem cells developed into darkly-pigmented cells that took on a cobblestone-like pattern. Klimanskaya suspected that these new cells were RPE, and subsequent tests confirmed her hypothesis. Now, a treatment for two diseases is being developed based on that chance finding.