Transplantation of Cultivated Corneal Endothelial Sheet in Primates

Abstract

Purpose: : Previously, we established a method for cultivating monkey corneal endothelial cells (MCECs) on a collagen type I carrier (Koizumi et al, ARVO 2005). The present study was designed to investigate the feasibility of cultivated MCEC sheet transplantation in eyes with corneal endothelial dysfunction.

Methods: : The experimental protocol was approved by the regulations of the laboratory animal care and use committee of Shiga University of Medical Science, and animals were handled in accordance with ARVO guidelines. MCECs from cynomolgous monkeys were cultivated on collagen type I carriers and used for transplantation. Under general anesthesia, the corneal endothelia of 5 eyes of 5 cynomolgous monkeys were scraped, with the denuded area confirmed by 0.04% trypan blue staining. A 6–mm diameter disc of cultivated MCEC sheet was brought into the anterior chamber in 3 eyes of 3 monkeys and attached to Descemet’s membrane (DM) by air. As controls, a collagen sheet without MCECs was transplanted in one eye, and a suspension of cultivated MCECs was injected into the anterior chamber in one eye. Healing was followed by biomicroscopy, ultrasonic pachymetry and non–contact specular microscopy.

Results: : In all 3 surgical eyes MCEC sheets were attached to DM the day after surgery. Mild corneal edema was observed, but this improved in 2 weeks with corneal thickness achieving preoperative levels by 3 months. Over an 8–month period, the 3 experimental corneas remained clear, and hexagonal cells at a density of 2200–2500 cells/mm² were observed by specular microscopy, though MCEC sheets detached from DM during the observation period. No signs of endothelial rejection were detected. Control eyes demonstrated vascularization and advanced corneal edema that precluded pachymetry and specular microscopy.

Conclusions: : We have established a model of cultivated corneal endothelial cell transplantation for corneal endothelial dysfunction using primates whose corneal endothelial cells do not proliferate in vivo. Our results suggest this is a useful model for long–term observation in advance of the future clinical application of cultivated corneal endothelial transplantation.

Keywords: cornea: endothelium • transplantation