BrdU Fluorescent Staining in a Niche of Posterior Limbal Cells Spreads to the Human Corneal Endothelium Following Mechanical Wounding.

Abstract

Abstract: : Purpose: Human corneal endothelial cells (HCE) are a monolayer of cells on the posterior side of the cornea. Their presence there is essential to deturgescence, the process of maintaining a clear cornea. Of themselves, these cells do not ordinarily divide once laid down. Recent evidence suggests that pluripotent cells reside at the HCE periphery. Here we suggest that cells located in a limbal niche anterior to the trabecular meshwork (TM) may act as a source of renewed HCE. Methods: Human corneal scleral buttons were incubated on the endothelial side in Optisol containing 5–Bromo–2'–deoxy–uridine (BrdU) for two days. Some corneas were previously mechanically wounded and others were not altered. After fixing the tissue, the tissues were exposed to anti–BrdU primary antibody and then secondary antibody coupled to fluorescein. Results: The wounded tissue demonstrated a continuous fluorescence from the anterior side of the TM (niche area) to the endothelial monolayer. In those tissues not subjected to mechanical wounding, fluorescent staining was only seen in the limbal niche area just anterior to the TM. Conclusions: The results are consistent with earlier supporting data (p53 family proteins, telomerase data, and cell density variations). Together they suggest that a putative stem cell niche exists and may supply new cells for both the TM and the endothelial monolayer.

Keywords: cornea: basic science • cornea: endothelium • wound healing