Stem cells could hold key to stopping vision lossBy Allyson BirdOffice of Development and Alumni Affairs
Gradually, a black hole appears. Right there -- where they always saw words on the page, actors in movies, faces of their own grandchildren -- they see only a dark blur.
Age-related macular degeneration holds a cruel grip on as many as 15 million Americans. The disease, over time, destroys the part of the retina that allows someone to see clearly.
People with age-related macular degeneration instead see only peripherally, with a telltale blind spot in the center of the vision. Treatments, such as laser surgery and monthly injections of medication into the eye, work best for patients in early stages of the disease, and they often only delay
Researchers at the Medical University’s Storm Eye Institute instead hope a potential cure is growing, one cell at a time, in Petri dishes at their laboratory.
Dr. Mark Fields studies whether he can engineer skin cells to replace the retinal cells in patients with age-related macular degeneration. The process, still years away from clinical application, uses stem cells generated from the patient’s own skin.
Not to detract from the other four senses, but Fields admittedly holds a particular fondness for sight. Vision, he reasons, helps to identify the world and a person’s place within it.
“Our eyes really are key to our understanding of who we are,” he said.
And the way eyes work is just shy of magic: Every cell in the retina plays a role in turning light pulses into the images we see. But eye cells, namely retinal pigment epithelium and photoreceptors, are no different from any other cells. They age and atrophy along with the rest of the body.
Fields and colleague Jie Gong, MD, PhD, under the leadership of Storm Eye Institute Director Dr. Lucian V. Del Priore, take a skin biopsy from an age-related macular degeneration patient and place it in culture in a petri dish, where they “reprogram” the cells to function as new retinal pigment epithelium and photoreceptors.
To do that, they select proteins that they want the cells to express and then deliver those proteins directly into the cells taken from the skin biopsy. The skin cells then function like programmable stem cells which, over time, begin to function like retinal cells. Physicians then could return those cells to the patient by injection into the retina or by placing them directly over the blind spot with what Fields calls a “scaffold” of the cultured cells.
Fields and Gong, who previously worked with Del Priore in New York, joined him at Storm Eye a little more than a year ago. Their work continues moving forward, thanks to financial support from the South Carolina Lions Eye Research Program.
Dona Van Leer, a member of the South Carolina Lions Eye Research Committee from Lake Wylie, said this project fits with the community service club’s mission since 1925, when Helen Keller addressed the Lions at a national convention in Ohio.
“She tasked us to be knights of the blind,” Van Leer said. “Our motto is about serving people with vision and hearing acuity problems.”
Van Leer’s professional background as a medical technologist piqued her personal interest in this project at Storm Eye. She worked in genetics in the mid-1960s, before stem cell research began.
“With what we’ve gone through with stem cells the past few years, it’s exciting,” Van Leer said. “They’re so close to creating your own stem cells, which is so much better than creating stem cells in any other manner. How far it’s come over the years is just amazing.”
Using the patient’s own skin cells avoids the ethical controversy associated with stem cells taken from human embryos. Plus, cell replacement is less likely to be rejected than a procedure that uses foreign cells. And knowing that the cells came from a patient with age-related macular degeneration means that researchers potentially can screen for drugs that could help other people with the same condition.
As Fields explained, “It’s personalized therapy.”
Trials with the Food and Drug Administration often take a decade before they reach consumers, and this project remains in the pre-clinical trial stages. In the meantime, Fields and his colleagues continue to take skin biopsies and watch them change under the microscope, one cell at a time.