Abstract
Purpose :
Corneal endothelial cells (CEC) form the posterior surface of the cornea and reside upon a thick basement membrane of extracellular matrix (ECM) known as Descemet’s membrane (DM). The principle function attributed to CEC is maintenance of corneal transparency through the coordinated transport of ions and water. Since CEC in adult corneas display poor capacity for proliferation, CEC dysfunction is typically treated by implantation of donor corneal tissue. Nevertheless, there have been growing reports of corneal transparency returning in some patients following the removal of dysfunctional CEC and DM. These observations suggest the potential for CEC regeneration via some form of wound healing response. Presumably, this process is partly mediated through the deposition of ECM components required to form a new DM, but little is known regarding this process. The purpose of this study is therefore to investigate the composition and distribution of ECM components secreted by CEC using an in vitro model.
Methods :
Cultures of human CEC were established from fragments of cadaveric donor DM/endothelium or passaged cells. These cultures were maintained for up to 5 weeks before being photographed and decellularized to expose secreted ECM. The composition and distribution of ECM components within the secreted ECM was subsequently analysed by immunofluorescence using antibodies raised to human collagen I, collagen III, collagen IV and fibronectin.
Results :
Two main types of CEC morphology were discernible within the cultures; compact monolayers of cobblestoned cells resembling the morphology of CEC in vivo, and cells with a more fibroblastic and migratory morphology. Following removal of cells, dense mats of ECM components were observed in areas associated with compact monolayers of cobblestoned cells, whereas sparsely scattered plaques or fibres of ECM components were associated with regions containing more fibroblastic cells. Nevertheless, collagen I, collagen III, collagen IV and fibronectin were detected in all of the ECM investigated.
Conclusions :
The ECM secreted by human CEC in vitro contains proteins associated with corneal wound healing as well as those associated with normal DM structure. The density of secreted ECM components is highest in areas of confluent CEC with a cobblestoned morphology similar to functional CEC in vivo. We therefore propose that adult CEC have the capacity to synthesize a new DM.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.