Abstract
Purpose: :
Epithelial downgrowth (ED) is a rare, sight-threatening complication that may occur following intraocular surgeries , characterized by uncontrolled proliferation of epithelium in the anterior chamber. We studied four cases of ED using neural and epithelial stem cell markers to test our hypothesis that cells that produce ED may be of epithelial stem cell origin.
Methods: :
Four specimens from four patients diagnosed with epithelial downgrowth were studied using double staining by immunohistochemistry. For the identification of corneal epithelial cells we used the following antibodies: CK5/6 , CK7 and AE1/AE3. To identify the cells expressing stem cell markers in the cornea, we used antibodies P63, CD133 and SOX2.
Results: :
All the sections showed one to four layers of corneal type epithelium lining the endothelial surface or iris. Immunohistochemistry showed that these cells were positive for AE1/AE3 and focally positive for CK7. Some of the basally located cells were positive for P63 and CD133 shows focal staining of epithelial cells on double stain. Sox2 was uniformly negative.
Conclusions: :
Our study demonstrates that epithelial downgrowth cells have a population of cells with characteristics of stem cells. Intraocular implantation of ocular surface stem cells, with proliferation and differentiation into epithelial cells may account for the major clinical characteristics of epithelial downgrowth.
Keywords: cornea: epithelium • proliferation • immunohistochemistry