Purpose: To examine the feasibility of cultivated corneal endothelial cell transplantation in a primate model.
Methods: Monkey corneal endothelial cells (MCECs) obtained from three cynomolgus monkeys were cultivated, with subcultures grown on collagen type I carriers for 4 weeks. The corneal endothelium of the right eye of six monkeys was mechanically scraped, after which a cultivated MCEC sheet was brought into the anterior chamber of four eyes and fixed to Descemet's membrane by air. As the control, a collagen sheet without MCECs was transplanted into one eye of one monkey, and a suspension of cultivated MCECs was injected into the anterior chamber in one eye.
Results: Cultivated MCECs produced a confluent monolayer of closely attached hexagonal cells that showed both ZO-1 and Na(+)-K(+) ATPase expression. In the early postoperative period MCEC sheets were attached to Descemet's membrane and corneal clarity was recovered. The recovered clarity was accompanied by a decrease in corneal thickness. Fluorescein DiI labeled donor corneal endothelial cells were detected on the host cornea on postoperative day 7. Six months after transplantation MCEC-transplanted corneas remained clear, and hexagonal cells were observed by in vivo specular microscopy with a density of 1992 to 2475 cells/mm(2). Control eyes showed irreversible bullous keratopathy that precluded pachymetry and specular microscopy.
Conclusions: A model of cultivated corneal endothelial transplantation for corneal endothelial dysfunction was established in primates whose corneal endothelial cells have less proliferative capacity in vivo. Our results suggest that this is a useful model for long-term observation in advance of the future clinical application of cultivated corneal endothelial transplantation.