A Duke University research team has zeroed in on a tiny “cleanup crew” inside the eye that appears to help keep pressure from creeping too high, a key issue in glaucoma. The group reports that immune cells called resident macrophages, tucked into the eye’s drainage tissues, clear away debris and help maintain steady intraocular pressure. In mouse experiments, when those cells were selectively removed, the eye’s drain clogged, fluid backed up and pressure climbed, suggesting a new angle for tackling glaucoma.
How the team showed it
The work, published March 9 in the journal Immunity, tracked fluorescently tagged resident macrophages in mouse eyes and then used selective depletion to see what happened when they disappeared. Without the cells, outflow resistance increased and intraocular pressure (IOP) rose. The experiments combined live imaging, genetic tools and direct pressure measurements to tie the cells’ cleanup role to the eye’s outflow homeostasis.
“This research helps us understand the role of the immune system in regulating eye pressure,” said lead author Katy Liu, M.D., Ph.D., in a Duke Health statement. Liu and her co-authors say that disrupting this macrophage cleanup crew in the conventional outflow tract may contribute directly to glaucoma.
Why the finding matters
Lowering intraocular pressure is currently the only treatment that has been proven to slow glaucoma, yet some patients still lose vision despite available drugs, laser procedures and surgeries, according to the National Eye Institute. The Duke study highlights a specific cell-level mechanism in the eye’s drainage pathway that might be targeted to restore more normal outflow, instead of only turning down the pressure with existing therapies. “Now we have a specific target for developing new therapies,” said corresponding author W. Daniel Stamer, Ph.D.
Next steps and who funded the work
Next, the researchers plan to track down and characterize the same kind of resident macrophages in human eye tissue and test whether boosting their cleanup activity can help normalize pressure in disease models. The study lists support from the National Institutes of Health, Research to Prevent Blindness, the Duke Strong Start Award, the Heed Fellowship and the American Glaucoma Society. Additional details on the study design, funding and author list are available through EurekAlert! and the journal entry in Immunity.
