Inhibitive. Overwhelming. Making everyday tasks a challenge. Blindness is a condition often considered extremely difficult to manage, much less cure. Most available “solutions” to make blindness manageable are simply palliative, aimed at dampening the level of discomfort that patients face. Many of these solutions are double-edged swords, coming with their own set of side-effects. One such treatment is the use of steroids which help reduce inflammation and repress the immune system, but side effects include possible infections. Alternatives like non-steroidal anti-inflammatory drugs may be useful (Harrison, 2016), but can cause corneal toxicity, a condition of the eye with symptoms like blurry vision, ocular pain, and tear formation (NCBI, 2006). For the 285 million people worldwide (World Health Organization, 2015) and 816,250 Canadians suffering from visual impairment (Facts on Seeing Limitations, 2016), the path may seem dark, but there is a ray of hope.
The solution stems from the process of regeneration. Some human tissue, like that of the liver, kidney, fingertips, and toes, has the ability to rebuild itself. The process of self-renewal depends on stem cells which can turn into differentiated, or specialized, cells based on need (Pellegrini et al., 2014). Limbal tissue (tissue at the border between the cornea and the sclera (Hopen et al., 1981)) shares this ability (Refer to Figure 1). Regenerative treatments for blindness are based upon the limbal tissue’s ability of self-restoration.
Developments in the use of limbal stem cells for ocular regeneration have increased in the last decade (Pellegrini et al., 2014), edging mankind closer and closer to a suitable cure. Success in new clinical trials on the use of Holoclar – a stem cell therapy used for patients with a deficiency of limbal stem cells due to ocular burns (Medical Dictionary Online, 2016) – shows great promise.
A recent study explored the use of limbal stem-cell therapy for long-term corneal regeneration. Researchers cultivated limbal stem-cells from the donor and transplanted harvested sheets of these cells into the patient’s eye over the damaged area. The placement of healthy stem-cells triggered the growth of the patient’s own cells, allowing the patient to rebuild his/her own cornea over time (Refer to Figure 2). They observed the therapy’s progress over a period of 10 years. Results indicated that the technique had a higher success rate for patients with a larger number of holoclone-forming cells (Rama et al., 2010). Holoclones are stem-cells with a tendency to form colonies and have a higher potential for growth (Medical Dictionary Online, 2016), enabling them to increase the corneal regeneration rate.
A discovery of this capacity is a major breakthrough in the dynamic field of medicine, and it’s effects will not be limited to the curing of blindness, but will extend far beyond into many other areas of health care. Encouraging this research will result in more breakthroughs and eventually a faster rate of implementation of research into medical practice.
Bibliography:
Centreforsight.com. Available at: <https://www.centreforsight.com/media/news/news/stem-cell-surgery-saved-mysight-daily-express> [Accessed 29 Oct. 2016].
Halle, M., 2009. Stem Cell Surgery Saved My Sight Daily Express | News | Centre for Sight. [online]
Harrison, L., 2016. Palliative care, support vital for patients who suffer vision loss. [online] OphthalmologyTimes. Available at: <http://ophthalmologytimes.modernmedicine.com/ophthalmologytimes/news/palliative-care-support-vital-patients-who-suffer-vision-loss?page=full> [Accessed 29 Oct. 2016].
Medical Dictionary, 2016. Medical Dictionary Online. [online] Online-medical-dictionary.org. Available at: <http://www.online-medical-dictionary.org> [Accessed 29 Oct. 2016].
NCBI, 2006. Corneal toxicity with systemic cytarabine NCBI. [online] Ncbi.nlm.nih.gov. Available at:<https://www.ncbi.nlm.nih.gov/pubmed/6939330> [Accessed 29 Oct. 2016].
Research Gate, 2008. Front and Side Diagram of Human Eye. [image] Available at:<https://www.researchgate.net/figure/232918663_fig1_Figure-1-A-front-and-side-diagram-of-the-human-eye-showing-the-sclera-conjunctiva> [Accessed 29 Oct. 2016].
Statistics Canada, 2016. Facts on Seeing Limitations. [online] Statcan.gc.ca. Available at: <http://www.statcan.gc.ca/pub/89-628-x/2009013/fs-fi/fs-fi-eng.htm>[Accessed 29 Oct. 2016].