Abstract
Purpose:
To validate various porcine collagen-based biomaterials for therapeutic regeneration of the corneal stroma in a model of intra-stromal keratoplasty.
Methods:
35 New Zealand white rabbits were operated with an IntraLase iFs 150kHz surgical femtosecond laser, to excise a thick disc of native stromal tissue. Native rabbit corneal tissue (autograft control) or various porcine collagen-based biomaterials were inserted into the intra-stromal pocket, in a surgical procedure termed FLISK (femtosecond laser-enabled intra-stromal keratoplasty). Rabbits were monitored for 2-3 months by optical coherence tomography and in vivo confocal microscopy. Following sacrifice and corneal tissue extraction, immunohistochemistry and transmission electron microscopy of corneal sections was performed.
Results:
The minimally-invasive surgical wound healed rapidly and without sutures, inflammation, rejection, or neovascularization. No epithelial downgrowth into the stroma was observed. Biomaterials employing various hydrations, thicknesses, synthetic cross-linkers, and structural stabilizers were well-tolerated without stimulating inflammation, and maintained corneal thickness and transparency postoperatively. Stromal myofibroblasts migrated to the implant margins and into the implant materials, confirmed by in vivo and ex vivo imaging, where they degraded the implant collagen and replaced this with new, host-produced collagen.
Conclusions:
Porcine-based biomaterials can serve as biodegradable scaffolds that support host cell infiltration and regeneration of the corneal stroma in vivo. This class of biomaterials, which is cost-effective to produce, has the potential to address a range of blinding corneal pathologies.
Keywords: 484 cornea: stroma and keratocytes •
687 regeneration •
741 transplantation