A probiotic can improve symptoms

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A probiotic bacterial strain may help fight dry eyes, a study in mice suggests. Image credit: Jonathan Knowles/Getty Images.
  • About 12% of the world’s population suffers from dry eye, a condition in which the eyes are unable to lubricate themselves sufficiently.
  • There is currently no cure for dry eye.
  • Researchers at Baylor College of Medicine in Houston, Texas identified a probiotic bacterial strain that helped improve dry eye via a mouse model.

Almost 12% of the entire world population suffers from dry eye, a condition where the eyes do not produce enough tears to keep them properly lubricated, causing discomfort.

Although there is currently no cure for dry eye, there are a number of treatments available to help treat the symptoms of the condition.

These treatments include over-the-counter eye drops, medicationsor procedures such as adding punctal plugs to the eye tear ducts.

Now, researchers at Baylor College of Medicine in Houston, Texas have identified a probiotic bacterial strain that helped improve dry eye via a mouse model.

This research was recently presented at ASM Microbe 2023, the annual meeting of the American Society for Microbiology.

While people may associate tears with crying, healthy eyes actually produce tears all the time. When a person blinks, these tears – known as tear film — are spread over the surface of the eye to provide lubrication, remove any foreign particles and protect the eyes from infection.

Sometimes a person’s eyes may not produce enough natural tears, causing dry eyes. This can happen for a number of reasons, including:

Symptoms of dry eye include:

If left undiagnosed and untreated, dry eye can cause eye infections and potential damage to the surface of the eye, known as cornea. Whether corneal lesions becomes severe, it can even lead to loss of vision.

In addition to medical treatments for dry eye, previous research shows that dietary changes can help fight the disease.

A study in 2019 found that omega-3 supplements significantly improved dry eye symptoms and signs in people with dry eye disease.

Another study in 2019, short-term vitamin A supplementation improved tear quality in people with dry eye disease.

Researching new treatments for dry eye is important, says Dr. Laura Schaefer, assistant professor of molecular virology and microbiology at Baylor College of Medicine in Houston, Texas, and lead author of this study.

“Despite the prevalence of dry eye — about 1 in 20 people in the United States — there are only a handful of drugs currently available to treat dry eye, and for some patients, these drugs don’t work very well. to improve symptoms,” she said. Medical News Today.

Dr Schaefer said she and her team decided to focus on looking at a probiotic bacterial strain in the gut to treat dry eye because their previous work showed a functional link between intestinal bacteria and symptoms of dry eye.

“We performed several experiments using gut bacteria isolated from Sjögren’s syndrome patients with severe dry eye, from healthy patients without eye disease,” she detailed. “When mice are colonized with gut bacteria from Sjögren patients, they develop worse dry eye under dry conditions than mice colonized with gut bacteria from healthy patients.”

“This suggests that healthy people’s gut bacteria protect the surface of the eye in dry conditions, and therefore a possible treatment route for dry eye would be probiotic bacteria that have similar protective effects,” added Dr Schaefer.

For this study, Dr. Schaefer and his team used a mouse model of dry eye. The mice were first given an antibiotic to kill the “good” bacteria in the gut. They were then exposed to very dry conditions and given either the probiotic bacterial strain, Limosilactobacillus reuteri DSM17938or saline as a control.

After 5 days, the scientists found that the mice given the probiotic bacterial strain had healthier and more intact corneal surfaces than those given the saline solution.

Additionally, the mice fed the probiotic bacteria also had an increased amount of goblet cells in their eye tissue. Goblet cells are cells that produce an essential component of tears called mucin.

“Our hypothesis was that the probiotic would protect the eye, and it was exciting to prove that to be true,” Dr. Schaefer said. “This particular probiotic strain, DSM17938, has been well studied and shown to reduce inflammation in other tissues, including the gut, and improve gut barrier function. It has not, however, been previously evaluated in the context of the eye.

“These results show that bacteria with anti-inflammatory effects in the gut can also reduce inflammatory conditions in the eye. A healthy diet low in harmful fats and high in fiber is known to nourish the ‘good’ bacteria that naturally live in our intestines, and the anti-inflammatory effects of these bacteria in the intestine can extend to other tissues in the body, including the eye.

– Dr. Laura Schaefer

DTM also spoke with Dr. Benjamin Bert, an ophthalmologist at MemorialCare Orange Coast Medical Center in Fountain Valley, Calif., about this study, in which he was not involved.

“It was actually quite a fascinating study to see the multiple components involved in both our understanding of dry eye disease and also in our future abilities to treat dry eye disease,” he commented.

We have seen previously that taking supplements – omega-3 supplements, for example – (has) been shown to be beneficial in the treatment of patients with certain types of dry eye. It is therefore fascinating to focus more on the gut microbiome as a potential treatment point,” added Dr. Bert.

Regarding the next steps for this research, he said that since it was being conducted via a mouse model, a study in humans would be needed.

“It would be really interesting to see this used as an adjunct in a human trial to really prove what their hypothesis is, that this is a significant benefit or a possible treatment that could be used for patients. suffering from dry eye,” he added.

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