Nanoparticles may prevent corneal graft rejections

Biodegradable nanoparticles that release medication into the eye may solve the issue of medicine compliance after corneal transplant surgery and help increase the rate of surgical success, according to an article in the Journal of Controlled Release.

Researchers at Johns Hopkins report that they divided rats that had undergone corneal graft surgery into four groups. One group was injected weekly for 9 weeks with a biodegradable nanoparticle loaded with corticosteroids for timed release of medicine. The other 3 groups received weekly injections of saline, placebo nanoparticles, or free dexamethasone sodium phosphate aqueous solution.

Treatments were given until the graft was deemed as having clinically failed or until the 9-week test period concluded. Researchers looked at corneal transparency, swelling, and growth of new blood vessels to decide if a graft had failed.

Among rats that received the nanoparticle loaded with corticosteroids, 65% of the treatment remained in the eye and did not leak within one week of the surgery. The concentration of the treatment also remained stronger than in the other three treatment groups. Additionally, there were no signs of swelling, and the cornea was clear throughout the test period. There were less instances of unwanted growth of new blood vessels in this group.

Two weeks after surgery, rats that received the placebo nanoparticle and saline injections had severe swelling, opaque corneas, and unwanted growth of new blood vessels, all indicating graft failure. After 4 weeks, rats that received free dexamethasone sodium phosphate aqueous solution all had graft failure as well. The only group that showed successful corneal transplant was the group of rats that received the corticosteroid-loaded nanoparticle injections. The grafts were still viable in 100% of these rats. The steroid-loaded nanoparticle treatment group showed no signs of corneal transplant rejection.

“That’s 100% efficacy, a very promising finding,” said Justin Hanes, Ph.D., director of the Center for Nanomedicine at the Wilmer Eye Institute at Johns Hopkins. “This type of treatment may also help prevent corneal transplant rejection in humans while making medicine adherence much easier on patients and their families.”

The nanoparticle drug delivery system could be paired with other drugs and used in other conditions, such as glaucoma, macular degeneration, and corneal ulcers.

To read the abstract of the study, click here.