No Interleukin 6 Increase Seen With Hydrogel, Silicone Hydrogel Contact Lenses

Neither hydrogel nor silicone hydrogel (SiHy) contact lens materials are associated with an increased interleukin (IL)-6 in the tear film, according to research results published in Contact Lens and Anterior Eye. 

Although it is well documented that soft contact lens materials rapidly deposit proteins, lipids, and other tear film components, there is a lack of literature on inflammatory protein deposition, including cytokines. Researchers evaluated 6 commercially available contact lens materials to evaluate the uptake of interleukins IL-1β, IL-6, IL-8, and tumor necrosis factor (TNF)-α onto hydrogel and SiHy contact lenses. 

Investigated materials included 2 conventional hydrogel materials — etafilcon A and omafilcon A — and 4 SiHy materials — balafilcon A, comfilcon A, senofilcon A, and somofilcon A. Researchers assessed these materials for their ability to update cytokines from solution through the Meso Scale Discovery (MSD) system. 

All 6 materials were soaked in standard cytokine solution. Results of this experiment showed no significant differences in cytokine concentration in the remaining solutions at 6 hours in the etafilcon A, omafilcon A, senofilcon A, or somofilcon A materials. At the same timepoint, uptake of IL-1β, IL-8, and TNF-α were “statistically different” compared with controls. 

In another experiment, researchers evaluated cytokine interest at lower and higher ranges of concentrations, sourced from the supernatant of human corneal epithelial cells on to 4 of the 6 materials. At 6 hours, comfilcon A and omafilcon A demonstrated a 18% to 21% uptake of TNF-α relative to the control at a lower concentration, with a mean remaining TNF-α concentration of 79%±3% pg/mL and 82%±2% pg/mL of the control, respectively. 

IL-6 and IL-8 uptake of higher concentrations were also investigated in etafilcon A and comfilcon A. No statistical differences between remaining concentrations of IL-6 on comfilcon A relative to control were noted at 8 days; results were similar for etafilcon A. There was, however, a statistical difference in IL-8 concentration in solutions that contained etafilcon A relative to control at 7 days, and a 20% uptake of IL-8 onto the same material in the same time-frame. 

“The 6 contact lens materials tested…did not exhibit any uptake of IL-6, and furthermore, did not exhibit more than 10±3% to 25±12% uptake of IL-1β, IL-8, and TNF-α,” the research says. Investigators add that further studies are necessary to evaluate the physiological relevance of this level of uptake. 

“Numerous factors could contribute to the reported increase in corneal infiltrative events with reusable silicone hydrogel materials, however, based on these results it appears that uptake of these 4 cytokines are unlikely to contribute to this finding,” according to the researchers. 

Reference

Mirzapour P, McCanna DJ, Jones L. In vitro analysis of the interaction of tear film inflammatory markers with contemporary contact lens material. Cont Lens Anterior Eye. Published online March 23, 2021. doi:10.1016/j.clae.2021.02.016