Supramolecular host-guest hyaluronic acid hydrogels for corneal endothelial cell delivery and epithelial wound healing

Abstract

Purpose : Corneal disease and scarring are major causes of blindness, with a need for improved treatment approaches. Hyaluronic acid (HA), a naturally occurring, biocompatible glycosaminoglycan with known corneal wound healing effects, is rapidly cleared from the eye. Supramolecular, non-covalent crosslinking modalities, including host-guest interactions, have been developed as ways to create biomaterial polymer networks with dynamic, reversible crosslinks. Here, supramolecular HA (s-HA) hydrogels were formed by cyclodextrin (CD) and adamantine (Ad) host-guest interaction to serve both as a potential vehicle for endothelial cells and as a possible promoter of epithelial wound healing.

Methods : S-HA hydrogels were synthesized by host-guest interaction between HA-CD and HA-Ad or HA-Ad-FITC. Primary corneal endothelial cells (CECs) were grown in culture and either covered with or encapsulated in s-HA hydrogel and evaluated using a live/dead assay at Time 0, Day 1, 2, and 3. To study epithelial healing, a total corneal epithelial debridement was performed, followed by application of s-HA, linear HA, or saline, with fluorescein examination on Day 1, 2, and 3 to determine wound size, and enucleated and fixed in paraformaldehyde for cryosectioning and immunohistochemical analysis on Day 3. Cryosections were stained for actin or nuclei, or immunostained for CD45 or vimentin and analyzed by confocal microscopy.

Results : Following encapsulation and needle injection, CECs showed greater than 90% viability, demonstrating the s-HA hydrogel to be a suitable vehicle. On Day 1, CECs remained dispersed within the hydrogel, but by Day 3, a subset of cells were seen to adhere to the tissue culture plate. In rats, all injured corneas were healed by Day 3. Animals treated with s-HA exhibited less corneal edema, fewer activated cells in the subepithelial stroma following wound closure, and reduced stromal expression of both CD45 and vimentin, with thickness and staining patterns more similar to normal controls than the linear HA or saline-treated eyes. Additionally, linear HA and saline treated eyes showed increased actin filament formation within stromal keratocytes compared to s-HA treated eyes and normal controls.

Conclusions : Supramolecular HA hydrogels have potential for corneal endothelial cell encapsulation as a delivery vehicle, as well as enhanced epithelial wound healing.

This is a 2021 ARVO Annual Meeting abstract.