One in three individuals have some type of reduced vision disease by the age of sixty-five (Quillen 1999). In fact, it is so common that most people just expect they will lose their vision if they get old enough. In most cases the common end point of this vision loss is the photoreceptor loss that happens in the retina. Without healthy photoreceptors, the neurological pathway is disrupted and leads to vision impairment or irreversible vision loss. However, in recent years, there have been many new findings regarding how the use of reprogramming stem cells could be a feasible option to reverse vision loss in the future.
Biraj Mahato, an experienced researcher at the University of North Texas Science Center, and his research team have expanded the current research in this field by experimenting with the best way to reprogram stem cells to serve as functional photoreceptors. They explore this in their article called, “Pharmacologic fibroblast reprogramming into photoreceptors restores vision.” This study was conducted by this research group in 2018 at the Laboratory for Retinal Rehabilitation and then later published in the British Journal “Nature” back in 2020.
Many researchers including Mahato use fibroblast as a host cell for this reprogramming process. Fibroblast cells are the most common cell in connective tissue and are readily available. Most of the fibroblast used in research are harvested from embryos. Mahato’s team started with a series of experiments mixing up different compounds; these researchers found that a combination of five compounds could effectively convert an embryonic fibroblast into a Photoreceptor-like cell called a CiPCs. Their experimental study then started by injecting these CiPCs into a group of mice. After a couple of weeks, the mice were put through a series of tests to examine if the mimic photoreceptors (CiPCs) could activate existing retinal circuitry and restore visual functions in mice. These tests included a light-aversion test where the mice were placed in a chamber where one part was sectioned off dark and the other was light, they then were monitored and recorded using a photocell-based system. Another test conducted was the Optomotor task. The mice were placed into a chamber with mirrors on the floor and ceiling. The walls were computer monitors that were used to project visual stimuli. The mice were then measured for visual acuity threshold and contrast sensitivity in each eye. The results of the trials were positive and overall led to the conclusion that the CiPCs cells did lead to restoration in some visual functions, and they are promising cell transplants for vision restoration in the future. The statistical results were that 6 out of 14 mice improved pupillary reaction. Subretinal transplantation of rod like CiPCs led to long term improvement in pupillary light reflex and restoration of normal visual behavior in the light aversion test (Mahato 2020).
This study was deemed a major success. However, like all other experiments, it does have its shortcomings and still needs to be much improved before it is safe to test on humans. Some areas of improvements are the small sample size and the success rate. This study was only performed on 14 mice and only 6 of which had improvements of vision. This shows that the CiPCs can work which is positive but also proves to be inconsistent. This improvement can come with time and refining their processes of reprogramming and injecting. Other researchers in the field such as Yuancheng Lu suggest that instead of making new cells, a better option is to regenerate the axon that has aged within the eye. He explores this in his article “Reprogramming to recover youthful epigenetic information and restore vision,” where he too has found success recovering vision within mice. Lu believes the key to recover vision is the DNA methylation patterns which causes the cells to age in the first place (Lu 2020). Besides Mahato and Lu, there are many other researchers who have different methods and ideas but they all correlate to regaining the loss of vision due to age related diseases. This goes to show that there could be multiple ways of restoring vision loss. All of which could be a readily practiced treatment in the foreseeable future.
Reversal of vision loss in elderly would be a major accomplishment. It would not only fix their apparent problems such as navigating through their house but it is also shown that it may affect many different aspects of their life such as their cognitive abilities, psychological capacity, and social functioning, which are all important contributors to successful aging (Bonnielin 2019). These studies also may lead to larger implications that solve not only vision diseases due to aging, but more types of blindness that affect different people all over the world.
Research in restoring vision has also been proven useful outside of vision loss and in the world of anti-aging. In their study Mahato’s group discovered a new function of the mitochondria that may lead to valuable information involving the regeneration of other cell types. In Lu’s article, he also viewed vision loss as a microcosm for aging as a whole. Learning more about cell regeneration in vision loss may lead us to all types of anti-aging practices.
Although these studies have been a great step in the right direction, they are still merely just the tip of the iceberg of what is possible with medical treatment of blindness and other anti-aging practices. Thanks to researchers like Mahato and their work reprogramming cells you may never have to fear losing the gift of seeing the beautiful world around us.
References
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Featured Image source:
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