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Stem Cells Show Potential in Treating AMD

If you wanted to provoke an emotionally driven argument about a medical issue with someone in the lay community, your best bet would likely be on the topic of stem cell technology. The issue has frequently appeared in political debates in the United States since the early 2000s, and is a common preserve of social conservatives and conspiracy theorists. The concerns and objections to stem cell technology are as myriad as their potential usage in medicine.

Stem cells are human cells that possess the ability to develop into many different cell types. This can range from muscle to brain cells, and in some cases they can also fix damaged tissue. While stem cells were originally postulated to be most useful in treating diseases like Alzheimer’s and paralysis, researchers now believe these cells may have broader application.

Stem cells come in two varieties, one of which is more prominent in the popular conscience. The first is embryonic stem cells which result from an in vitro fertilization procedure. These stem cells are then donated to research labs as they are pluripotent, which means that they can turn into more than one type of cell. However, this type of stem cell can be extremely controversial given the way they are harvested for science.1

Looking Beyond the Hysteria

Stem Cells Show Potential in Treating AMD
Stem cells made easy.

The second type are adult stem cells (which also come in two varieties). The first originates from fully developed tissues such as the brain, skin and bone marrow. The second type is induced pluripotent stem cells, which are adult stem cells that have been changed in a lab to be more like embryonic stem cells. Induced pluripotent stem cells appear to act in the same manner as embryonic stem cells but thus far, scientists have not yet found that these can develop into any kind of cell or tissue.

Now initially, the link between stem cells and ophthalmology might appear tenuous at best, given that researchers believe they are best suited to treat conditions like Alzheimers. However, consider the broader picture and their use in ophthalmology is more logical — especially for a condition like age-related macular degeneration (AMD). Like Alzheimers, AMD is a degenerative and incurable condition, therefore its progression can only be slowed and it is a disease that can significantly alter a patient’s quality of life.

The use of stem cells in treating AMD is primarily focused on the retinal pigment epithelium (RPE). This is the multifunctional monolayer located at the back of the eye and is required for the survival and function of the light-sensing photoreceptors. In AMD, the loss of RPE cells leads to photoreceptor death and permanent blindness.2

Looking at the Research from Down Under

Stem Cells Show Potential in Treating AMD
Someone got their stem cells today…

In Advancing a Stem Cell Therapy for Age-Related Macular Degeneration, a group of researchers at the Clem Jones Centre for Regenerative Medicine at Bond University, Gold Coast, Australia, examined the issue of stem cells to mitigate AMD. They stated that RPE cell transplantation to halt or reverse vision loss, thus preventing the death of photoreceptor cells, is one of the most viable applications of stem cell therapy in the field of regenerative medicine. They concluded that “early results from clinical trials indicate that transplantation of human pluripotent stem cells derived RPE cells is safe and can improve vision in AMD patients.”

However, the Australia-based researchers warned that hPSC-RPE cell production protocols used in clinical trials are insufficient. This concern is echoed by the authors of Stem Cell Treatment for Age-Related Macular Degeneration: the Challenges, Prof. Mandeep S. Singh and Dr. Robert MacLaren, who warn that no clear animal or human data exists on how quickly photoreceptors degenerate in vivo and escape the rescue window following acute RPE removal or exposure to blood components. They believe that if stem cells are to be harnessed to properly treat patients with AMD, it will be crucial to define the time window for treatment with empirical data.3

Both researchers took time in their paper to emphasize that while considerable concerns remain, overall there has been major progress in the development of stem cells in treating AMD and other conditions. Therefore, stem cells and ophthalmology are certainly an area where you should say “watch this space,”’ as research remains relatively scarce despite the major interest expressed in the subject. Hopefully in 2021, and in the coming years, we will be able to examine more research about this fascinating field and its potential applications.

References

1.` University of Rochester Medical Centre. What Are Stem Cells? Available at https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=160&contentid=38. Accessed on January 18, 2021.

2. O’Neill HC, Limnios IJ, Barnett NL. Advancing a Stem Cell Therapy for Age-Related Macular Degeneration. Curr Stem Cell Res Ther. 2020;15(2):89-97.

3. Singh MS, MacLaren RE. Stem Cell Treatment for Age-Related Macular Degeneration: the Challenges. Invest Ophthalmol Vis Sci. 2018;59(4):AMD78-AMD82.

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types of stem cells
2 years ago

As the name points out, both types of stem cells are named based on whether they originate from: embryos or the adult body. Each function differently in the nervous system and have unique assets as well as limitations.