Abstract
Purpose::
The corneal endothelium (CE) is reluctant to divide in humans beyond the 2nd decade and CE cells do not readily grow in culture. This has prompted a search for a stem cell population that may give rise to these cells. Previous work has already suggested that stem cells reside in the posterior limbus. This region includes the trabecular meshwork (TM) and a transition zone between the TM and the corneal endothelium, i.e. Schwalbe’s line.
Methods::
We tested for markers of stem cells and transient amplifying cells in flat mount and transverse sections of fixed human corneas with attached limbal tissues. Primary antibodies against nestin, alkaline phosphatase, telomerase and Oct-3/4 were used with fluorescent-labeled secondary antibodies. Appropriate controls as well as bright field comparisons were included.
Results::
Nestin, alkaline phosphatase and Oct-3/4 staining occurred at discrete regions of Schwalbe’s line. Positive staining for telomerase occurred in both the TM and the peripheral endothelium. However, no staining was seen for nestin, alkaline phosphatase and Oct-3/4 in the corneal endothelium.
Conclusions::
The results suggest that a stem cell population that supports the corneal endothelium resides in distinct locations of Schwalbe’s line. This may indicate that a population of stem cells exists apart from those previously indicated to be in the TM.
Keywords: cornea: endothelium • trabecular meshwork