Abstract
Purpose :
To evaluate a bioengineered collagen construct (BPC) corneal implant using a femtosecond laser- assisted anterior lamellar keratoplasty rabbit models.
Methods :
BPC corneal implants were fabricated using a carbodiamide- crosslinking system and characterized for their physiochemical properties using optical, mechanical and in vitro biocompatibility test methods. The optimum formulations were then tested in vivo. For in vivo study, 23 male New Zealand white albino rabbits were used. Two surgical techniques, both assisted by femtosecond laser were used to excise the rabbit cornea vertically at 7mm diameter and 280μm depth, including the epithelium and part of the stroma. Animals were divided into four different groups depending on the implant type (aurograft/BPC) and surgical technique (Flap/ALK). The first group were autograft (Auto Flap-ALK). The second group with the same procedure but with 440µm- thick BPC implants (BCP Flap-ALK). The third group were autograft (Auto-ALK) and the last group operated with femtosecond laser- assisted flap keratoplasty for the implantation of 280 µm- thick BPC (BCP-ALK). Rabbits were monitored up to months by optical coherence tomography and in vivo confocal microscopy. The rabbits were then sacrificed and their corneas excised and tested for immunohistochemistry.
Results :
The BPC had superior light transmission charactristics than rabbit and human donor cornea and were mechanically stable with optimum elasticity and biocompatibliblity toward Human Corneal Epithelial Cells (HCECs) . Among the two techniques used Flap-ALK method showed better results with no inflammation or rejection of the implants. The thicker BPC implants with deeper insertion were well-tolerated without any inflammation. The corneal thickness and transparency were maintained postoperatively. The results showed the migration of stromal fibroblasts in to the BCP implant and formation of newly synthesized collagen was observed.
Conclusions :
The Flap-ALK method was found to be a better surgical technique for the implantation of thicker BPC scaffolds (cost effective) that can be an alternative method to support host cell infiltration and regeneration of the corneal stroma in vivo.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.