Abstract
Purpose :
The shortage of cadaveric donor corneas limits the treatment of corneal blindness worldwide. In situ-forming biomaterial matrices that fill and regenerate corneal defects address this major clinical need. We aimed to compare the in vivo wound healing response of collagen-hyaluronate (HA) hydrogels crosslinked with riboflavin-based photocrosslinking chemistry to those crosslinked with a more specific and light-free crosslinking chemistry in the filling of deep corneal stromal defects in vivo.
Methods :
Lamellar stromal defects over a 3.5 mm diameter area in rabbit corneas were filled with collagen-HA hydrogels crosslinked by UVA (365 nm) light exposure and riboflavin as a photosensitizer (photocrosslinked collagen/HA) in 6 eyes and in situ-forming collagen-HA hydrogels crosslinked with bifunctional PEG-succinimide (collagen-PEG/HA) in 6 eyes. Corneal wound healing, thickness, and opacity were evaluated using slit lamp exam, optical coherence tomography (OCT), and pachymetry on days 7,14, and 28.
Results :
A 70% ± 5% cut depth was achieved without significant difference between the two groups. At 28 days, overall corneal thickness as well as stromal and epithelial thickness in the corneas treated with collagen-PEG/HA gel were not significantly between the two treatment groups. However, collagen-PEG/HA was found to have restored more than 85% of the stromal and overall thickness which was not statistically significantly different from normal corneas on day 28, whereas the photocrosslinked collagen/HA gel group showed significantly lower stromal and overall thickness compared to normal corneas. There was no statistically significant difference in epithelial healing and corneal opacity between the two groups. The epithelium healed completely in the majority of the eyes within days 14 and in 100% of the eyes healed within days 28.
Conclusions :
In-situ forming collagen-PEG/HA gel and photocrosslinked collagen/HA gel promoted corneal stromal thickness restoration and supported epithelial wound healing. Corneas treated with collagen-PEG/HA gel improved corneal thickness restoration to a greater extent than photocrosslinked collagen/HA. Further work is merited to evaluate the potential impact of crosslinking specificity on corneal tissue regeneration after matrix therapy.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.