Dr. Tongalp Tezel: Gene therapy and stem cell transplantation show promise in age-related macular degeneration
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On-Screen Title: Innovating novel approaches to restore vision loss in age-related macular degeneration (AMD)
Dr. Tongalp Tezel: AMD affects almost 20 million people in the United States, and almost 2 million of them has lost their central vision. The current treatment is injecting intravitreal anti-VEGF blocking agents to temporarily stop the leakage and the growth of the blood vessels.
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Dr. Tongalp Tezel: The use of these drugs has many challenges. Most of the people require several repeated injections which carry the inherited risks of retinal detachment, bleeding and infection. Almost 30 to 40% of the patients do not adhere to these painful injections, and also 10 to 15% of the people do not respond to this treatment.
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Dr. Tongalp Tezel: One way to overcome this problem is programming patients’ own retina cells to produce the same drug that we are injecting. Gene treatment involves a surgery, during which the surgeon introduces an adeno-associated virus carrying a DNA fragment into the subretinal space. This DNA then integrates into the DNA of the retinal pigment epithelial and photoreceptor cells and then produces the same anti-VEGF drug that we keep injecting.
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Dr. Tongalp Tezel: At NewYork-Presbyterian we are offering this to our patients in a clinical trial. The early trials show that this is a very effective way of suppressing the VEGF inside and obtaining almost better or same benefit of frequent injections.
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Dr. Tongalp Tezel: The next idea is why don't we replenish the cell loss in the eye of the patients with macular degeneration? We can engineer the subretinal space by using stem cells. Retinal pigment epithelial cells are just outside the photoreceptor cells. These cells support the photoreceptors metabolic activity. Once we replenish these cellular defects, we are expecting that the photoreceptor cells can start functioning. Because even in the late scars, if you look at the histopathology, 40 to 60% of the photoreceptor cells are still intact. That means that if you create an environment that these cells can function, the patients can regain the sight again.
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Dr. Tongalp Tezel: Our ability in the lab to create this stem cells allowed us to start a clinical trial in collaboration with New York Stem Cell Foundation and the National Eye Institute. We created retinal cells from six donors. And then we are going to transplant them under the retina. Replenishing the retinal pigment epithelial cells is going to help the patient to see.
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Dr. Tongalp Tezel: All my colleagues here at NewYork-Presbyterian and Columbia, we are here to reach beyond the conventional treatments and develop new treatments for patients suffering from macular degeneration, to give hope and improve the quality of life of our patients.
On-Screen Title: Clinical trials are currently underway for gene therapy and stem cell transplant with promising early results
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