Eye health and the microbiome
Blog vol 6.23. Eye health and the microbiome
What is crazy is that eye tissue is fully exposed to the environment and is not overrun by bacterial colonies. There are protective surfaces, tears that repel and keep bacteria numbers down, as well as an ever-ready immune system. Some ophthalmologists call the eye “paucibacterial”, meaning it has few or little bacteria, only 6 bacteria per 100 eye cells, as compared to the human gut that hosts literally trillions of bacteria in total.
Microbiome – a community of microorganisms (such as bacteria, fungi, and viruses) that inhabit a particular environment and especially the collection of microorganisms living in or on the human body (Meriam-Webster)
We know that the eye has its own microbiome and thrives by balancing these organisms. For example, the latest research on the bacteria, Corynebacterium mastitidis, has shown that this organism helps to recruit white blood cells by encouraging interleukin 17 release from the eye, which causes the release of antimicrobial ’alarmin’ peptides into the tears, which helps put the immune system on alert. We need these helpful bacteria to prevent dysbiosis, the disruption of the eye’s microbiome.
Fungi can also cause dysbiosis. A serious condition like keratomycosis occurs when there is an overgrowth of fungi like Aspergillus or Candida. Too much fungi is obviously a problem, but a lack of fungal diversity on the surface of the eye is also a problem, a symptom of an underlying condition such as Sjögren’s disease.
Sjögren’s syndrome is an interesting condition. It is an autoimmune syndrome that works primarily on the secreting glands of the mouth and the eyes. As a result, people with Sjögren’s usually have extreme dry eye. The latest research from Baylor University, headed up by Dr. Laura Schefer et al., is finding a connection between the gut and Sjögren’s (access the research article here). Her research with mice is suggesting that gut bacteria release molecular signals which cause the lymphocytes to become overactive, especially targeting the secreting cells of the mouth and eyes.
A connection to gut bacteria? The eyes? It is possible.
So what does this mean? Of course, more research. 1. Researchers are genetically modifying Corynebacterium mastitidis to produce its own interleukin (10) to alert the immune system for protection. 2. They need to find the offending gut bacteria to reduce lymphocyte damage in Sjögren’s. 3. Probiotics is another area of research with much potential. Butyrate (short chain fatty acid) has been shown to reduce eye dryness and a ‘friendly’ strain of Limosilactobacillus reuteri bacteria when ingested, helps to create intact corneal surfaces. Can the consumption of helpful probiotics boost eye health? Again, it is possible.
No doubt a start, it does give one “food for thought”, and for dry eyes.
The good doctor
