Biosynthetic corneal substitute implantation in dogs.
OBJECTIVE
To assess integration of a biosynthetic corneal implant in dogs.


METHODS
Three normal adult laboratory Beagles underwent ophthalmic examinations, including slit-lamp biomicroscopy, indirect ophthalmoscopy, applanation tonometry, and Cochet-Bonnet aesthesiometry. Biosynthetic corneas fabricated from glutaraldehyde crosslinked collagen and copolymers of collagen and poly(N-isopropylacrylamide-co-acrylic acid-co-acryloxysuccinimide, denoted as TERP) were implanted into dogs by a modified epikeratoplasty technique. Ophthalmic examinations and aesthesiometry were performed daily for 5 days and then weekly thereafter for 16 weeks. Corneal samples underwent histopathological and transmission electron microscopy examination at 16 weeks.


RESULTS
Implants were epithelialized by 7 days. Intraocular pressure was within normal range throughout the study. Aesthesiometry values dropped from an average of 3.67 cm preoperatively to less than 1 mm for all dogs for the first postoperative weeks. By week 16, the average Cochet-Bonnet value was 1.67 cm, demonstrating partial recovery of functional innervation of the implant. No inflammation or rejection of the implant occurred, and minimal haze formation was noted. Light microscopy revealed thickened but normal epithelium over the implant with fibroblast migration into the scaffold. On transmission electron microscopy, the basement membrane was irregular but present and adhesion complexes were noted.


CONCLUSIONS
Biosynthetic corneal implantation is well tolerated in dogs, and the collagen-polymer hybrid construct holds promise for clinical application in animals and humans.
Department of Surgical Sciences, University of Wisconsin-Madison, Madison, WI, USA. bentleye@svm.vetmed.wisc.edu
Ellison
E
Bentley
Christopher J
CJ
Murphy
Fengfu
F
Li
David J
DJ
Carlsson
May
M
Griffith
D000178:Acrylamides / Q000737:chemistry; D000818:Animals; D001187:Artificial Organs; D001672:Biocompatible Materials; D024042:Collagen Type I / Q000737:chemistry; D003315:Cornea / Q000294:innervation / Q000601:surgery / Q000648:ultrastructure; D003432:Cross-Linking Reagents; D004285:Dogs; D019084:Fluorescent Antibody Technique, Indirect; D020007:Implants, Experimental; D008689:Methacrylates / Q000737:chemistry; D009416:Nerve Regeneration / Q000502:physiology; D016900:Neurofilament Proteins / Q000378:metabolism; D009882:Ophthalmic Nerve / Q000502:physiology; D010865:Pilot Projects; D019919:Prosthesis Implantation
D000178:Acrylamides; D001672:Biocompatible Materials; D024042:Collagen Type I; D003432:Cross-Linking Reagents; D008689:Methacrylates; D016900:Neurofilament Proteins; C407035:poly(N-isopropylacrylamide-co-N-acryloxysuccinimide-co-2-hydroxyethyl methacrylate)