Abstract
Purpose :
Millions of people suffer from corneal diseases, but less than 2% of patients have access to corneal transplantation due to the shortage of cadaveric donor corneal tissue. Moreover, rapid and complete epithelial wound healing is critical to prevent infection and scarring that can lead to blindness. Biomaterial matrices have been investigated as a way to fill corneal defects and support epithelialization. Loading growth factors into defect-filling hydrogels is a promising approach toward enhancing corneal epithelialization. Here, we incorporate epidermal growth factor (EGF) into in situ-forming collagen gels to study the effect of their controlled release from within defect-stabilizing matrices on epithelial cell adhesion and proliferation.
Methods :
EGF was added to a neutralized collagen solution and crosslinked either via N-hydroxysuccinimide chemistry using 8-arm PEG or via UV light using riboflavin as a photosensitizer. We compared the gels’ degradation as well as the proliferation, migration, and phenotype of corneal epithelial cells (CECs) seeded on these gels and the epithelial wound healing response in ex vivo organ culture model. Cell viability and cytotoxicity were measured using colorimetric assays. We also executed an in vitro scratch assay which mimics cell migration during wound healing in vivo. The presence of biomarkers that promote epithelial healing were compared across three groups: cells without treatment, collagen gels alone, and EGF encapsulated within PEG- or UV-crosslinked collagen hydrogels.
Results :
Encapsulated EGF accelerated in vitro corneal epithelial cell proliferation and migration. Gels loaded with EGF also exhibited a lower degradation rate and accelerated corneal wound healing in our organ culture studies. Immunohistochemical analysis exhibited expression of 4-hydroxynonenal within the epithelium and alpha-smooth muscle actin within the surrounding stroma for 8-arm PEG collagen and UV riboflavin gels with EGF. Immunohistochemical studies demonstrated that both types of EGF-loaded collagen gels fostered tight junction formation and maintained normal epithelial phenotype.
Conclusions :
Our study suggests that collagen gels with encapsulated EGF can fill corneal defects and enhance corneal epithelial regeneration. Further work to investigate the effects of EGF-loaded collagen gels in vivo are merited.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.