In A New Study, Researchers Discovered An "Unexpected Link Between The Gut And The Eye," Showing That Gut Bacteria May Play A Role In Causing Blindness That's Associated With Certain Hereditary Eye Conditions

New research conducted by scientists in the United Kingdom has found that gut bacteria might play a role in causing blindness associated with certain hereditary eye conditions.

Interestingly, the study also indicates that treatments using antimicrobials could potentially treat these vision impairments.

Conducted by an international team of researchers, the study revealed that gut bacteria were found in the eyes' damaged regions in cases of vision loss stemming from a specific genetic mutation. This mutation is known to lead to eye diseases that can cause blindness.

So, scientists from University College London, working alongside Chinese scientists, suggest that the genetic mutation in question might weaken the body's immune response. Then, this reduction in defense mechanisms could enable detrimental bacteria from the gut to travel to the eyes, ultimately leading to blindness.

Our gut hosts trillions of bacteria, many of which are crucial for proper digestion. Yet, among these microbes, some can pose a threat to our health.

The team initially aimed to study the impact of the Crumbs homolog 1 (CRB1) gene, which is active in the retina— or the thin layer of cells at the back of the eyeball. This gene plays a key role in forming the blood-retina barrier, which controls the entry and exit of substances in the eye.

Moreover, the CRB1 gene is linked to hereditary eye disorders. It is identified as the underlying cause for about 10% of Leber congenital amaurosis (LCA) cases and 7% of retinitis pigmentosa (RP) cases globally.

In mouse experiments, the researchers found that the CRB1 gene plays a crucial role in maintaining the integrity of the lower gastrointestinal tract. This discovery marks the first instance such a function has been observed.

Within the lower gastrointestinal tract, the CRB1 gene helps combat pathogens and detrimental bacteria by controlling the exchange between gut contents and the body's internal environment.

JoshuAA/peopleimages.com - stock.adobe.com - illustrative purposes only, not the actual person

The team observed that a specific mutation in the gene, which diminishes its function, can compromise the protective barriers in both the retina and the gut. This breach allows gut bacteria to migrate through the body to the eye, potentially causing lesions in the retina that lead to vision loss.

Crucially, the study also found that administering antimicrobials– such as antibiotics– prevented vision loss in a group of mice. However, it's important to note that these treatments did not repair the damaged cell barriers in the eye.

The appearance of hereditary eye diseases can greatly differ among individuals. Some may experience symptoms in early childhood, whereas others may not encounter any problems until they reach adulthood.

Once the deterioration begins, it is irreversible and affects individuals for the rest of their lives. Traditionally, the focus for developing treatments has been on gene therapies.

But, this research suggests that antimicrobials could play a role in slowing down the progression of eye diseases linked to the CRB1 gene. So, future research will explore the potential of this approach in humans.

"We found an unexpected link between the gut and the eye, which might be the cause of blindness in some patients. Our findings could have huge implications for transforming treatment for CRB1-associated eye diseases. We hope to continue this research in clinical studies to confirm if this mechanism is indeed the cause of blindness in people and whether treatments targeting bacteria could prevent blindness," concluded Professor Richard Lee, the study's co-lead author.

"Additionally, as we have revealed an entirely novel mechanism linking retinal degeneration to the gut, our findings may have implications for a broader spectrum of eye conditions, which we hope to continue to explore with further studies."

To read the study's complete findings, which have since been published in the journal Cell, visit the link here.

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