From Gut to Eye: New Approaches to Dry Eye Disease
Scientists are embracing novel approaches to treating disease – the use of faecal implants and tablets to treat gut problems and serious conditions such as depression, Parkinson’s disease and multiple sclerosis, was one of the big medical stories in 2018. Now both the gut and ocular surface microbiomes are being explored by researchers chasing a cure for one of the most common and persistent eye conditions – dry eye.
Dr Judith Flanagan, Leader of Ocular Therapeutics at Brien Holden Vision Institute, says studies have demonstrated a link between the immune system and dry eye disease, prompting them to investigate whether probiotics taken orally will reestablish proper immune system function and combat the problem.
“There is substantial evidence associating the gut microbiome with systemic inflammation in disease states such as diabetes, irritable bowel syndrome and dermatitis,” she said. “It’s also been found that taking probiotics, which act to help restore a disrupted bacterial community in the gut, can have a positive effect on both systemic and localised immune system function.
(an) avenue being explored is the use of topical treatments at the ocular surface in an attempt to ‘rebalance’ the ocular microbiome
“So, working within an ecological framework, we’re investigating whether these probiotic supplements can reconstitute a healthy microbiome, either at the site of the disease or enterically, and act to reduce the severity of signs and symptoms of dry eye disease. Along these lines, another avenue being explored is the use of topical treatments at the ocular surface in an attempt to ‘rebalance’ the ocular microbiome.
“It’s possible that the microbial community on the eye’s surface plays a role in the development of meibomian gland dysfunction. A change to the balance of this commensal community may lead to eyelid inflammation, changes to the composition of the eye’s tears or to the quality of the meibomian lipids that form the upper most layer of the tear film.
Dr Flanagan said research has shown that low dose oral antibiotics are useful in treating meibomian gland dysfunction but the concentrations used are below levels needed to eliminate bacteria and the effects are instead, anti-inflammatory.
“Another benefit of low dose antimicrobials is that they inhibit bacterial lipase production, reducing the concentration in the tear film of these enzymes that can act to degrade the lipid layer of the tears.”
We’re currently recruiting participants for this trial of the topical ointment
However, with concerns that long term oral antibiotic use can diminish our bacterial communities, and that exposing bacteria to non-biocidal levels of these drugs can induce antibiotic resistance, the researchers are proposing an alternative approach.
“Rather than using antibiotics to target the lipase enzymes, we are developing a bacterial lipase inhibitor ointment derived from natural products (coconut oil) that can work to rebalance a healthy ocular microbiome and deliver increased ocular comfort and reduced dry eye disease,” said Dr Flanagan.
“We have already shown in the lab that our novel agent can inhibit production of bacterial lipase without being antimicrobial. It has also been shown by others that bacteria never develop resistance to this agent and that this lipase inhibitor does not affect the healthy bacteria that we need on the ocular surface. We hope, through a clinical trial, to provide initial evidence that this approach can reduce the signs and symptoms of dry eye disease by naturally allowing the bacterial community to find an ecological balance.
“We’re currently recruiting participants for this trial of the topical ointment (which is applied on the skin around the eye rather than in the eye) and planning for an oral probiotics study in the near future, so if there are optometrists working in the inner Sydney area who have patients that might be interested we would love to hear from them,” said Dr Flanagan.
Article appeared on mivision, 28th February 2019