Abstract
Purpose::
To investigate the role of apoptosis in different pathologic processes that are common indications for corneal transplantation: bullous keratopathy, Fuchs’ dystrophy, failed grafts, and keratoconus.
Methods::
Ten corneal buttons from each pathologic diagnosis were examined using TdT-dUTP terminal nick-end labeling (TUNEL) to determine the quantity and location of cells undergoing apoptosis. The apoptosis cascade was further characterized by immunohistochemistry for associated cellular markers (Fas, FasL, TRAIL).
Results::
Results show apoptosis in varying corneal layers with associated cellular markers and promoters of apoptosis present predominantly within the stroma. All disease processes show apoptosis in the epithelium and stroma, while the failed grafts exhibited less endothelial apoptosis than the other three. The failed grafts showed greater TRAIL staining in the stroma than the other three processes. Graft failure stromal cells react positively with FasL to a greater extent than the stromal cells in Fuchs'. In keratoconus there was less Fas staining than in either bullous keratopathy or failed grafts.
Conclusions::
The evidence indicates that apoptosis plays a role in each of the different pathologic processes studied. These findings may aid in the search for ways to manipulate apoptosis for preserving corneal function.
Keywords: apoptosis/cell death • cornea: clinical science • transplantation