The Link Between Tear Polyunsaturated Fatty Acids, Eicosanoids, and Dry Eye

— Revisiting old interventions can inspire new interventions, says Anat Galor, MD

MedicalToday

A study presented at the American Academy of Ophthalmology meeting examined the relationship between tear polyunsaturated fatty acids (PUFAs), eicosanoids, and dry eye symptoms. In this exclusive video, , from the Bascom Palmer Eye Institute at the University of Miami Miller School of Medicine, discusses the research.

Following is a transcript of her remarks:

Another nociceptive trigger in this whole dry eye umbrella are inflammatory mediators. And there's been a lot of focus on T cells and cytokines and how they impact dry eye and how they need to be targeted.

But another aspect of the body's response is lipid-derived products that can either be pro-inflammatory or anti-inflammatory -- and the PUFAs that make lots of different eicosanoids, and the eicosanoids have both pro-inflammatory mechanisms and resolving mechanisms, so anti-inflammatory. And it's a conversation. These things are coming and going, and it's like a symphony.

So again, really exciting because not as much focus has been given to these mediators, both in activation of inflammation and termination of inflammation. But we have a cross-sectional study and in a cross-sectional study, as things are going up and things are going down, you don't really know what's a cause and a consequence. But it's more of a starting of a conversation. I think it's important because if we understand which molecules are driving which aspects of dry eye, there's certainly potential for new interventions or revisiting old interventions in a certain population.

So when I say old interventions, there's always this big controversy in the dry eye world on the benefit of omega-3s, which are the starting substrate for a lot of these pro-resolving eicosanoids. We've had some really large, well-designed thoughtful studies that failed to see a signal. We found some smaller studies that did find some benefit. And I think the more we understand about the role of these mediators in the dry eye umbrella, the more we're going to be able to find targeted therapy, whether it's oral supplementation or topical supplementation. And there are other things other than omega-3s that interfere with this pathway. So that's not the only way to do it.

I think the punchline in general is if you came to me as a doctor and you said I had back pain, I wouldn't be like, here is one medication for your back pain. That's ridiculous. Do you have a muscle issue? Do you have a nerve issue? Do you have a spine issue? And I think dry eye is the same. Every company is looking for the one treatment that treats all dry eye, and that's ridiculous. So as a community, we need to do a better job identifying the underlying mechanisms that are driving symptoms and signs in the individual patient so we can offer precision-based intelligent therapies for their disease. So if someone is just in a mold infested home, or has an allergy to cockroaches and they have a cockroach infestation, then environmental manipulation makes a lot of sense. And someone who has a T cell-driven autoimmune disease like Sjogren's, graft-versus-host disease, blocking those T cells makes a lot of sense.

But in other people it may be more of an imbalance between pro-resolving and pro-inflammatory eicosanoids. And then that may be the subcategory that we really need to focus on some of these newer interventions.

So I truly believe that all of these interventions that we have studied are probably beneficial in the right patient population, but none of them are going to cure all dry eye. And the biggest gap in the field to me is trying to pair the intervention with the patient. And the missing link is the diagnostic tools to figure out what's going to work in which patient.

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    Greg Laub is the Senior Director of Video and currently leads the video and podcast production teams.