Abstract
Purpose::
To investigate whether transplantation of tissue-engineered human corneal endothelial cell (HCEC) sheet grafts into corneas denuded of endothelium could restore corneal function and clarity in a rabbit model.
Methods::
Using plasma chemistry, the thermo-responsive surfaces (TRS) were obtained by chemically grafting poly(N-isopropylacrylamide) (PNIPAAm) on the culture substrates. Untransformed adult HCECs isolated from eye bank corneas were labeled with PKH26 and cultivated on the TRS for 3 weeks at 37°C. When the culture temperature was lowered to 20°C, confluent HCEC cultures were harvested as transplantable cell sheets. Gelatin hydrogel discs prepared by solution casting methods were used as cell sheet delivery matrices (CSDM). Bioengineered HCEC sheets along with CSDM were transplanted to rabbit corneas denuded of endothelium. Postoperative evaluations including clinical observations and histological studies were performed periodically throughout the study.
Results::
When cultured on TRS, the HCECs derived from older donor tissue kept their phenotypic characteristics and proliferative capacity. After detachment from TRS at a low culture temperature, the structure and function of HCEC sheet grafts resembled those of native corneal endothelium. Under slit-lamp biomicroscopy, rabbit corneas became edematous and opaque after their endothelial cells were removed. Corneal clarity was significantly improved in HCEC sheet-grafted corneas. Additionally, the rabbit corneas have returned to a nearly normal thickness indicating the function of implanted HCEC sheets. Successful graft-host integration was demonstrated after transplantation of well-organized HCEC monolayers.
Conclusions::
The present study suggests that tissue-engineered HCEC sheet transplantation using TRS and CSDM is very effective to restore corneal transparency and function and can potentially offer a new therapeutic strategy for corneal endothelial cell loss.
Keywords: cornea: endothelium • cornea: basic science • transplantation