Contact lenses loaded with lactoferrin (LF) could prevent the effects of oxidative stress on the tear fluid, reports a study in the June 2015 Cornea.1
Researchers from the University of Milano-Bicocca in Italy incubated three types of contact lenses—galyfilcon A, filcon V and falcon 1B—for one, three or five hours at room temperature in an apolactoferrin (iron-depleted form of lactoferrin; abbreviated as apoLF) 2mg/mL solution. Results indicated maximum loading at five hours was 61±19μg for falcon V, 39±4μg for filcon 1B and 42±14μg for galyfilcon A.
After incubation, the lenses were placed in a phosphate buffer and the quantity of released apoLF was evaluated at one, two, three and 24 hours. Data showed the release of adsorbed apoLF was 49±12% for filcon V, 66±20% for filcon 1B and 100% for galyfilcon A.
In the second part of the study, researchers treated TsA cell models with 250μM H2O2 to induce oxidative stress and observed the effect of LF on cell viability, finding that while 50μg/mL apoLF had a positive effect, 50μg/mL LF did not. This indicates the presence of accessible iron-binding sites is necessary for LF to protect against oxidative stress, the researchers say.
Using the same cellular model, researchers next evaluated the lactoferrin-loaded contact lenses for treatment purposes by incubating TsA cells with contact lenses loaded or unloaded with apoLF and evaluating the effect of induced oxidative stress. Results indicated the apoLF-loaded lenses had a mitigating effect on the number of dead cells compared with the control lenses; specifically, 10.5±1.2% vs. 36.2±4.7% for filcon V, 20.9±1.6% vs. 31.8±2.5% for filcon 1B and 19.4±2% vs. 37.3±2.7% for galyfilcon A. In fact, the researchers note, all of the contact lenses loaded with apoLF counteracted the H2O2 treatment for at least 24 hours.
Tear fluid contains antioxidative compounds that protect the corneal epithelium from the effects of ultraviolet radiation, direct exposure to air and chemical agents. In cases of oxidative stress, the levels of these compounds can be drastically reduced, leaving the epithelium open to the development of anterior eye disorders such as keratoconus, dry eye and Sjögren’s syndrome.1 Results from this study indicate, however, that “LF-loaded contact lenses may represent a new therapeutic approach to treating ocular surface pathologies characterized by high levels of oxidative stress,” the researchers conclude.
1. Pastori V, Tavazzi S, Lecchi M. Lactoferrin-loaded contact lenses: eye protection against oxidative stress. Cornea 2015 Jun;34(6):693-7.