News Statement
Wednesday, 13 September 2022
New discoveries may enhance the development and efficacy of therapeutics.
By combining traditional eye imaging techniques with adaptive optics – a technology that improves imaging resolution – researchers at the National Eye Institute (NEI) have demonstrated for the first time how cells in the eye’s different tissue layers are affected in people with choroideremia, a rare genetic disorder that causes blindness. Their research, supported by the NEI Intramural Research Program, has been published in Communications Biology. The National Institutes of Health include NEI.
Head of the NEI Clinical and Translational Imaging Unit, Johnny Tam, Ph.D., combined adaptive optics with indocyanine green dye to visualize live cells in the retina, including light-sensitive photoreceptors, retinal pigment epithelium (RPE), and choroidal blood vessels. His team was able to determine the amount to which choroideremia disturbs these tissues, information that could be used to develop successful treatments for choroideremia and other disorders. RPE is a layer of pigmented cells that is crucial for photoreceptor nutrition and survival.
Choroideremia is more prevalent in men than in women since the disease-causing gene is placed on the X chromosome. Since men have only one copy of the X chromosome, a mutation in the gene leads males to develop more severe symptoms, whereas females, who have two copies of the X chromosome and one functional copy of the gene on the other X chromosome, typically exhibit lesser symptoms.
“One of the most important findings of our study was that both males and females with choroideremia have significantly enlarged RPE cells,” stated Tam. We were astonished to see that several cells had increased in size by as much as fivefold.
The RPE cells of female participants in the study appeared both larger and healthy. According to Tam, this may explain why women with choroideremia have milder symptoms. Photoreceptor and blood vessel layers were impacted to a lesser degree in both male and female study participants, indicating that RPE disruption plays a crucial role in choroideremia.
Tam’s adaptive optics is not routinely tested in eye clinics during diagnostic procedures. Surprisingly, his group discovered that it is possible to detect larger RPE cells using only a commercially available scanning laser ophthalmoscope and indocyanine green dye.
Using an established instrument in the clinic, we can monitor and follow the cellular health of the RPE layer, which is not immediately apparent. This could be useful for determining which patients would benefit most from therapy approaches, according to Tam.
This news release explains an elementary study finding. Fundamental research deepens our understanding of human behavior and biology, which is essential for the development of new and improved methods of illness prevention, diagnosis, and treatment. Each research advance builds on previous discoveries, frequently in unanticipated ways. Without core basic research, the majority of clinical advancements would be impossible. Visit https://www.nih.gov/news-events/basic-research-digital-media-kit for more information about basic research.
NEI oversees federal efforts to reduce vision loss and improve quality of life via vision research by generating innovation, encouraging collaboration, increasing the vision workforce, educating the public and key stakeholders, and extending the vision workforce.
NEI funds basic and clinical science projects to discover sight-saving medicines and provide options for individuals with vision loss.
For additional details, please visit https://www.nei.nih.gov.
About the National Institutes of Health (NIH): The NIH is the nation’s medical research organization and consists of 27 Institutes and Centers. The Health and Human Services Department The NIH is the principal government organization that conducts and supports basic, clinical, and translational medical research and investigates the causes, treatments, and cures for both common and rare diseases. Visit www.nih.gov for more information on the NIH and its initiatives.
NIH…Transforming Research Into Health®
References
Nancy Aguilera, Tao Liu, Andrew J. Bower, Joanne Li, Sarah Abouassali, Rongwen Lu, John Giannini, Maximilian Pfau, Chelsea Bender, Margery G. Smelkinson, Amelia Naik, Bin Guan, Owen Schwartz, Andrei Volkov, Alfredo Dubra, Zhuolin Liu, Daniel X. Hammer, Dragan Maric, Robert Fariss, Robert B. Hufnagel, Brett G. Jeffrey, Brian P. Brooks, Wadih M. Zein, Laryssa A. Huryn, Johnny Tam*.
Adaptive optics reveals widespread subclinical cellular alterations across a neural-epithelial vascular network in choroideremia