University of Pittsburgh researchers developed a cytokine coating for silicone hydrogel lenses they believe could provide a sustained treatment for dry eye. They presented their finding on Sunday at ARVO 2019 in Vancouver.

Interleukin-4 (IL-4) has been shown to polarize macrophages from the inflammatory M1 phenotype—which is prevalent in dry eye disease—to the anti-inflammatory M2 phenotype.¹ IL-4 can be incorporated into a nanometer-thick coating for mitigation of the foreign body reaction to implantable polypropylene mesh, but the application to other devices has not yet been established, the study abstract notes.

Investigators rinsed senofilcon A lenses and then dipped them into polymer solutions of opposite charges. They observed the surface coating by immersing the lenses in alcian blue dye for 30 minutes followed by a distilled water rinse. Researchers then incubated the coated lenses in solution containing chondroitinase ABC and chitosanase enzymes (or in solution void of enzymes) to mimic in-vivo conditions. They collected lenses at various points over the 28-day study period to determine the release profile and kinetics of the IL-4 release.

The study found a uniform and conformal blue stain remained on lenses dipped in the oppositely charged polymers (compared with a control lens), showing successful application of the polymeric coating to the lens, investigators said. Additionally, IL-4 release kinetics from a coated lens incubated with enzymes showed a sustained release of IL-4 over several days, the researchers added.

There was little release of IL-4 from a coated lens in the absence of enzymes, indicating the coating was degraded primarily by enzymatic means, the study noted.

“Our results support the hypothesis that our polymeric IL-4 releasing coating can be applied to contact lenses with a resulting sustained release of drug over days vs. the transient burst release seen with eye drops,” the investigators wrote in their meeting abstract.

Future in-vivo work is necessary to determine if these coated lenses can help to mitigate inflammation associated with dry eye, they added.