Possible Mesenchymal Progenitor Cells In The Corneal Endothelium?

Abstract

Purpose: : Corneal endothelium (CE) is essential to maintain corneal transparency. Loss of CE cells ultimately leads to blindness necessitating corneal transplantation. Progenitor cells of the CE might serve as the basis for further approaches in tissue engineering to create functional CE grafts. However, in-depth knowledge of cells with precursor or stem cell-like properties for CE cells is needed. As the exact anatomical locations of those cells are not clearly identified yet we systematically studied the distribution and localization of CE cells with possible mesenchymal and stem-cell characteristics in human and mouse CE.

Methods: : The distribution of possible mesenchymal stem cells was studied conclusively by examining CD44, CD73, CD90, CD105 and stro-1 in mouse and human CE. Immunohistological analysis was performed by whole mount staining of human and mouse (C57BL6) corneas.

Results: : Among cell surface factors studied so far CD44 expression was identified in single cells located in the peripheral parts of human CE and in the limbus, but not in central parts of cornea. Moreover, CD44 could be detected at cell borders of specific cell clusters throughout the endothelium. Approximately 7% of all endothelial cells were found to be positive for CD44. In the periphery of mouse corneal endothelial cells CD90 positive cells could be detected.

Conclusions: : Our results identify CD44 positive cells with potential stem cell properties in distinct anatomical localization such as peripheral part CE and the limbus. These findings suggest that peripheral corneal tissue might be a promising source of future tissue engineering approaches for corneal endothelium.

Keywords: cornea: endothelium • cornea: basic science • anterior segment