Preclinical testing of a novel hydrogel film made from cross-linked hyaluronic acid (HA) suggests that the polymer can rapidly accelerate the healing of large corneal burns, re-epithelializing them by 48 hours after the film is placed into the inferior fornix.1
Rapid recovery. The study, conducted in New Zealand white rabbits, found that corneas treated with the film, made of cross-linked, thiolated hyaluronic acid (CMHA-S), achieved complete re-epithelialization at 48 hours. In contrast, untreated eyes never had complete epithelial regrowth during 14 days of follow-up. The researchers found that both groups experienced some regression of epithelialization by the end of the study. However, the treated group retained significantly better re-epithelialization—83% versus 63% for untreated eyes.
Other findings. The treated eyes showed a 50% reduction in area of corneal opacity at the 14-day mark, while the untreated eyes had a 16% reduction. In addition, the treated eyes had significantly less edema, possibly because the compound inhibited the release of inflammatory mediators and cytokines.
Method of action. The cross-linking of CMHA-S into a translucent film enables the HA, long known for its protectant and lubricating properties, to be released slowly over time and to persist longer in the eye than a non–cross-linked liquid HA drop would, said Barbara Wirostko, MD, with EyeGate Pharmaceuticals and based in Salt Lake City.
“The film remains intact and in place longer than eyedrops and is less likely to break down. Thus, it may promote wound healing over an extended time period, especially in cases of severe trauma,” she said. In the rabbit study, the film remained intact in the fornix for at least 14 days.
From animals to humans. A CMHA-S gel formulation has been available for several years as a treatment for dry eye and corneal wounds in animals (Remend, Bayer Animal Health), and EyeGate is developing it for use in humans, Dr. Wirostko said. In a pilot clinical study, post-PRK epithelial defects treated with the gel were, on average, 29% to 36.9% smaller as early as postop day 1 than those in eyes managed with a bandage contact lens and artificial tears.2
The company also is exploring the possibility that CMHA-S film can be used as a carrier for therapeutic molecules such as antibiotics. Dr. Wirostko said that this capability has already been demonstrated preclinically. “The film provides an alternative way of delivering the hyaluronic acid polymer and potential therapeutics in a sustained-released manner in severely traumatized eyes, potentially reducing or eliminating the frequent use of eyedrops.”
1 Griffith GL et al. Burns. 2018;44(5):1179-1186.
2 Durrie DS et al. J Cataract Refract Surg. 2018;44(3):369-375.
Relevant financial disclosures—Dr. Wirostko: EyeGate: E,O.
For full disclosures and the disclosure key, see below.
Full Financial Disclosures
Dr. Chévez-Barrios NASA: S.
Dr. Foster None.
Dr. Khawaja Allergan: C,L; Grafton Optical: L; Novartis: C; Thea: C.
Dr. Wirostko EyeGate: E;O.
||Consultant fee, paid advisory boards, or fees for attending a meeting.
||Employed by a commercial company.
||Lecture fees or honoraria, travel fees or reimbursements when speaking at the invitation of a commercial company.
||Equity ownership/stock options in publicly or privately traded firms, excluding mutual funds.
||Patents and/or royalties for intellectual property.
||Grant support or other financial support to the investigator from all sources, including research support from government agencies (e.g., NIH), foundations, device manufacturers, and/or pharmaceutical companies.
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