In Vivo Functionality of a Corneal Endothelium Transplanted by Cell-Injection Therapy in a Feline Model

PURPOSE. To evaluate the functionality of a corneal endothelium reconstituted by injection of corneal endothelial cells (CEC) in the anterior chamber of a feline model. METHODS. We operated the right eyes of 16 animals. Eight underwent central endothelial scraping and injection with 2 x 10(5) (n = 4) or 1 x 10(6) (n = 4) feline CEC supplemented with Y-27632 and labeled with 3,3'-Dioctadecyl-5,5'-Di(4-Sulfophenyl)Oxacarbocyanine (SP-DiOC18[3] or DiOC). After total endothelial scraping, two eyes were injected with 1 x 10(6) labeled CEC and Y-27632. The central (n = 3) or entire (n = 3) endothelium was scraped in six eyes followed by Y-27632 injection without CEC. Subjects were positioned eyes down for 3 hours. Outcomes included graft transparency, pachymetry, CEC morphometry, histology, electron microscopy, and function and wound healing-related protein immunostaining. RESULTS. Postoperatively, corneas grafted with 2 x 10(5) CEC and centrally scraped controls displayed the best transparency and pachymetry. Corneas grafted with 1 x 10(6) CEC yielded intermediate results. Entirely scraped controls remained hazy and thick. Histopathology revealed a confluent endothelial monolayer expressing sodium-potassium adenosine triphosphatase (Na+/K+-ATPase) and zonula occludens-1 (ZO-1) in corneas grafted with 2 x 10(5) CEC and centrally scraped controls, a nonuniform endothelial multilayer without expression of functional proteins in centrally scraped corneas grafted with 1 x 10(6) CEC, and a nonfunctional fibrotic endothelium in entirely scraped grafts and controls. Expression of DiOC in grafts was scarce. CONCLUSIONS. Injected CEC contributed little to the incompletely functional endothelium of grafted corneas. Y-27632 injection without CEC following scraping reconstituted the healthiest endothelium. Further studies investigating the therapeutic effect of Y-27632 alone are needed to validate these conclusions.