A Novel Stem Cell-Based Therapy for Dry Age-Related Macular Degeneration
Virginia Knepper Doyle was recently diagnosed with dry age-related macular degeneration (AMD). She immediately sought treatment for her condition but had already lost the ability to recognize faces. “I see people in my daily life that I probably know, but I cannot tell who they are,” says Doyle when describing what it is like to have AMD.
What is AMD?
Age-related macular degeneration is one of the nation’s leading causes of blindness in the elderly, with more than two million people affected today.
AMD is characterized by a loss of retinal pigment epithelial (RPE) cells, which are located in the retina in the back of the eye. The retina contains photoreceptors (light sensitive cells), which capture images and send them to the brain. Ultimately, the loss of RPE cells leads to the death of the photoreceptors. AMD can progress to cause significant impairment in the ability to read, recognize faces or drive.
There are two forms of AMD: wet and dry. The majority of patients have dry AMD, where deposits form under the retina, leading to deterioration of the light-sensing cells. To date, there are no treatments for dry AMD.
“Every day, I see patients who have gone blind or are going blind, who need therapy. We are incredibly excited that we have developed a minimally invasive therapy that can give hope back to those suffering from this devastating disease,” says Mark Humayun, MD, PhD, co-director of the USC Roski Eye Institute and co-inventor of Argus II, the first FDA-approved retinal prosthesis.
Humayun, along with David Hinton, MD, USC professor of pathology, neurological surgery, ophthalmology and associate dean for vision science, received a $38 million grant from the California Institute for Regenerative Medicine (CIRM) to develop a stem cell-based therapy for AMD. Through a cross-disciplinary approach, they assembled a team of experts comprised of four major schools and institutions including the USC Roski Eye Institute, University of California, Santa Barbara, California Institute of Technology (Caltech) and City of Hope to execute this interdisciplinary initiative.
Scientists from USC Roski Eye Institute and UC Santa Barbara focused their efforts on the root cause of dry AMD — the degeneration and loss of RPE cells. “The most ideal strategy in developing a treatment for AMD would be to regenerate RPE cells. They are also surgically accessible,” says Hinton. Scientists in the Hinton lab pioneered a methodology differentiating RPE from stem cells, purifying and growing them as confluent monolayers.
Stem Cell-Based Therapy
This treatment takes regenerated RPE cells and seeds them onto a synthetic membrane designed by Caltech scientists and engineers, which is then placed underneath the diseased portion of the retina. The implanted RPE scaffold (manufactured by City of Hope) is localized to support and replenish photoreceptors, which would help restore and prevent further vision loss in patients with dry AMD.
The stem cell therapy successfully decreased progression of retinal degeneration in animal studies that were conducted by Biju Thomas, PhD, USC assistant professor of research in ophthalmology.
“This stem cell-based therapy represents cutting-edge technology in several different fields and provides a real chance at improving the lives of millions of patients with disabling vision loss,” says Amir Kashani, MD, PhD, USC assistant professor of clinical ophthalmology and the principal investigator of the upcoming phase I clinical trial.
Hope for AMD Patients
“I am worried about my grandchildren getting this, and I think stem cell research is the hope for them,” says Virginia Knepper Doyle, dry AMD patient (quote provided by CIRM).
For more information on the clinical trial please visit the below links: