Abstract
Purpose :
Cornea transplantation suffers from a severe global shortfall, with over 12 million patients worldwide awaiting transplantation according to the WHO. Therefore there is a high need for tissue-engineered alternative that can replace conventional corneal grafting. The aim of this study is to investigate recombinant human collagen type I (RHCI) hydrogels as a substitute corneal transplant.
Methods :
In vitro biocompatibility of RHC I hydrogels was tested in a genotoxicity (VITOTOX), cell viability (PrestoBlue) and proliferation (BrdU) assay. Composite grafts were generated using primary limbal epithelial stem cells (LESC) and characterized using immunohistochemistry, electron micrscopy and qPCR analysis. To test bio-integration and degradation, acellular hydrogels were implanted as a corneal implant in mini-pigs with a follow-up of 1 year.
Results :
RHCI generates transparent and ultrathin hydrogels that withstand manipulation. Hydrogels show no genotoxic effect, and cell tend to adhere and proliferate well to the hydrogel with cell viability and total outgrowth being comparable to tissue culture plastic and amnion. When cultivated on RHCI, primary LESC keep expressing their undifferentiated adherent stem cell genotype and phenotype. In vivo, RHCI hydrogels show good biocompatibility as hydrogels remain intact, transparent, elicit minimal inflammation and integrate within the surrounding tissue. No difference was observed with control allografted corneas in the animal model.
Conclusions :
Primary LESCs can successfully be cultivated on RHCI hydrogels using a standardized xeno-free GMP-grade cultivation protocol. Its favorable optical characteristics, relative microbial resistance, successful composite graft generation and biocompatibility prove that RHCI is a highly promising scaffold for ocular tissue engineering. The hydrogels will be brought into humans as a first-in-human trial in 2020.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.