A Vision for the Future: Stem Cell Therapy for Retinal Diseases
Gabriele Barrocas | March 19th, 2024
In the United States alone, there are about 11.8 million people with retinal diseases, including photoreceptor degeneration, glaucoma (irreversible loss of vision around the edge of the eye), and diabetes-related retinopathy.
The retina is a thin layer of tissue on the back wall of the eye that contains millions of photoreceptors, known as rods and cones. Here, the retina sends visual information to the brain through the optic nerve. In diabetes, tiny blood vessels in the back of the eye can deteriorate, causing the retina to swell, distorting vision. In the center of the retina is the macula, an area that provides sharp vision that’s required to read and see fine detail. Those suffering from macular degeneration experience a progressive loss of central vision. Similar to this is retinoschisis, a disease diagnosed in childhood that causes progressive loss of vision. Overall, retinal diseases could seriously affect vision and could potentially cause blindness.
In a lecture focused on development and genetics in my General Biology class here at Vanderbilt, my instructor Dr. Carl Johnson began a discussion about stem cells. Stem cells have the potential to develop into many different types of cells in the body, from muscle cells to brain cells to retinal cells. I was immediately fascinated as he asked the question: “Could this ability to differentiate into any type of cell have applications to medical problems where there is a loss of cells, and stem cells might be used to replace the missing cells?” I was intrigued. Prior research has made strides in using stem cells to cure Parkinson’s, where researchers implant stem cells into a region of the brain called the substantia nigra. In rat trials, the stem cells differentiated into dopamine-producing cells and relieved the symptoms of Parkinsons. The potential applications of this technology in humans inspired me to think of other ways that stem cells could help people medically.
Dr. Johnson then talked about a research group at UCLA that implanted human embryonic stem cells into the retinas of two legally blind people. The research was a success and both patients experienced improvement in their vision.
In recent years, stem cell therapy has been investigated to restore vision for those suffering from retinal diseases, advancing the field of ophthalmology. Due to stem cells’ unique ability to self-renew and differentiate, this therapy proves to be a groundbreaking treatment in enhancing the quality of life in patients with ocular diseases. To date, embryonic stem cells, retinal progenitor cells (another type of cell found in the eye that has differentiation capabilities, mesenchymal stem cells (found in bone marrow), and induced pluripotent stem cells (derived from adult somatic cells) have been previously tested.
Closer to home, studies at the Vanderbilt Eye Institute have targeted photoreceptors and retinal ganglion cells to regenerate the retina, restoring vision. David Calkins, director for research at the Vanderbilt Eye Institute, says, “the ultimate goal is to inject these stem cell-derived ganglion cells into the eye, form connections and really integrate into the retina.” I think this field has a lot of promise. Our understanding of stem cells is increasing rapidly and the ability for scientists to stimulate stem cells to take on certain characteristics is an important one. These cells can restore eye functioning and ultimately recover vision for those suffering from retinal diseases.
References
Gaddam, S., Periasamy, R., & Gangaraju, R. (2019). Adult stem cell therapeutics in diabetic retinopathy. International Journal of Molecular Sciences, 20(19), 4876. https://doi.org/10.3390/ijms20194876
Labusca, L., Herea, D. D., & Mashayekhi, K. (2018). Stem cells as delivery vehicles for regenerative medicine-challenges and perspectives. World journal of stem cells, 10(5), 43–56. https://doi.org/10.4252/wjsc.v10.i5.43Leng, Y., Li, X.-J., Li, C.-Y., & Bai, D. (2021). Insights into stem cell therapy for diabetic retinopathy: A Bibliometric and visual analysis. Neural Regeneration Research, 16(1), 172. https://doi.org/10.4103/1673-5374.286974