Seeing the Future: How Retinal Organoids Might Hold the Key to Curing Blindness

We use cameras every day. They’re on our phones, in buildings, and even inside us. Yes, you heard that right. Our eyes, those uniquely intricate organs that we use to perceive the world around us, are more similar to a camera than you might think. Although one is made up of cold machinery and the other of flesh and blood, some parallels can be drawn between their components.

When photons of light hit the eye, they pass through a hole called the pupil. You might have noticed that your pupil expands or contracts when light levels change. This movement is regulated by the iris, the colorful ring surrounding the pupil, similar to how a photographer adjusts a camera’s opening to let in different amounts of light. The light then travels through the lens of your eye, resembling the lens of a camera, focusing the light into a clear image. In a camera, light is reflected onto sensors, which is then converted into an electrical signal. In the eye, the retina acts as that sensor. The retina is made up of specialized neurons called photoreceptors, which convert photons into electrical signals that our brains can interpret. With this assortment of parts working together in such a complex, delicate system, it is no wonder why many diseases of the eye are so difficult to treat.

Diagram of an Eye
Image credit: Maggie Liu

Retinal organoids, or lab-grown three-dimensional tissue cultures, are assisting in the search for a possible cure for blindness from retinal degeneration. Retinal organoids can mimic the structure, function and complexity of a human retina. They are grown from special cells that can differentiate into any cell type in the body called pluripotent stem cells. The stem cells are embedded in a special concoction of necessary nutrients and scaffolding. When exposed to certain growth factors and conditions, they will self-assemble into organoids that will share all of the cell types and structures like those of the retina.

Kim Edwards, a graduate student researcher of the Gamm Lab at the University of Wisconsin-Madison, gave some insight as to how organoids are cultured.

“You can imagine that organoid being like a little fish,” Edwards said. “You have these plastic dishes where you have your organoid or your fish. That organoid is going to be bathed in media that has…all of its food. We’re replacing that food, and that organoid is letting waste out into that media. So, just like a fish, it’s kind of living in that liquid.”

Now, researchers are looking at potential applications of retinal organoids to model retinal disease progression and provide further insight into its advancement. Dr. Praveen Susaimanickam, a postdoctoral researcher who is also in the Gamm Lab, offers an example where retinal organoids can be used to study the onset of congenital blindness.

Dr. Susaimanickam observed, “When the baby is born, it’s already born with blindness because the disease progression has already happened. But here in the retinal organoids, you can actually introduce those mutations and see how exactly the cells were lost. These little moments are really useful because whatever you missed that happened in the human already, you can replicate.”

Another promising use of retinal organoids is within the field of cell transplantation. One of the main causes of blindness is the death of photoreceptor cells in the retina. Unlike most cells, these can’t be regrown, especially considering the complex structure of the retina.

“The retina is like a layer cake,” Edwards said. “You have all these different layers and they’re perfectly lined up. When you cut into a cake, you have this beautiful arrangement of everything.”

Researchers are currently exploring whether cells grown from retinal organoids can be transplanted into patients with blindness from retinal degeneration.

Whether using them as models of disease or as a means for cell transplantation, retinal organoids offer exciting new opportunities to advance what we know about our eyes. As the technology improves and further research is done, these organoids may lead to additional discoveries that can change the future of treating retinal diseases and degeneration. Hopefully, with retinal organoids, our future can be made clearer.

  • The eye works similar to the way a camera works.
  • Retinal organoids are lab-grown three-dimensional tissue cultures.
  • Scientists are using retinal organoids to study disease and explore potential treatments, including treatments of various eye diseases.

Sources

Barbuzano, Javier. “Organoids: A new window into disease, development and discovery,” Harvard Stem Cell Institute. November 2, 2012. https://hsci.harvard.edu/organoids Accessed 8/2023

Cleveland Clnic article: “Retina.” https://my.clevelandclinic.org/health/body/22694-retina-eye Accessed August 2023.

González, F., Boué, S. & Belmonte, J. Methods for making induced pluripotent stem cells: reprogramming à la carte. Nat Rev Genet 12, 231–242 (2011). https://doi.org/10.1038/nrg2937

Interview with Dr. Praveen Joseph Susai Manickam, Research Associate, and Kim Edwards, Graduate Research Assistant, Gamm Lab, Waisman Center, University of Wisconsin – Madison, Madison, WI. Interview by Amber Fei on July 18, 2023.

Li X, Zhang L, Tang F and Wei X (2021) Retinal Organoids: Cultivation, Differentiation, and Transplantation. Front. Cell. Neurosci. 15:638439. doi: 10.3389/fncel.2021.638439

Nguyen KH, Patel BC, Tadi P. Anatomy, Head and Neck: Eye Retina. [Updated 2023 Aug 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK542332/

Reichenbach A, Bringmann A. Glia of the human retina. Glia. 2020 Apr;68(4):768-796. doi: 10.1002/glia.23727. Epub 2019 Dec 3. PMID: 31793693.

ScienceDirect article. “Extracellular Matrix: An Overview.” www.sciencedirect.com/topics/medicine-and-dentistry/extracellular-matrix. Accessed August 2023

University of Wisconsin – School of Medicine and Health website article, “ UW Study finds Photoreceptor Cells from Retinal Organoids can Replace Key Functions of Vision,” https://www.med.wisc.edu/news-and-events/2022/february/photoreceptor-cells-replicate-key-vision-function/ Accessed August 2023.

Yin X, Mead BE, Safaee H, Langer R, Karp JM, Levy O. Engineering Stem Cell Organoids. Cell Stem Cell. 2016 Jan 7;18(1):25-38. doi: 10.1016/j.stem.2015.12.005. PMID: 26748754; PMCID: PMC4728053.

Editorial Team

  • Chief Editor: Annika Singh
  • Team Editor: Aanya Bulusu
  • Image Credit: Maggie Liu
  • Social Media Lead: Melia Hillman

Mentor

Elizabeth Doughman is the Managing Editor of Poultry Future where she covers the intersection of new technologies and consumer trends in the poultry industry.

Content Expert(s)

Praveen Susaimanickam, Ph.D. is a postdoctoral researcher of the Gamm Lab at the University of Wisconsin-Madison. His work currently involves understanding the development of retinal photoreceptors.


Kim Edwards is a graduate student researcher of the Gamm Lab at the University of Wisconsin-Madison. Her work currently involves using pluripotent stem cells to model inherited retinal disorders.

About the Author

Amber Fei

Amber Fei is a rising senior living in New Providence, New Jersey where she attends Union County Magnet High School. Passionate about biomedical engineering and eager to promote science literacy, Amber is excited to improve her writing and communication skills through cSw. This past summer, she was an intern at Oertel Orthopedics, a specialized brace and prosthetics company. As an active member of her community, Amber plays volleyball, is Sergeant-at-Arms of her marching band where she plays clarinet and is co-president of her Future Business Leaders of America chapter. In her free time, Amber enjoys playing with her dog, spending time with friends and family, and adding to her mineral collection.