Characterization Of EMP2 Positive Cells In Proliferative Vitreoretinopathy (pvr) And Epiretinal Membranes(erm)

Abstract

 

Purpose:

 

Epithelial Membrane Protein 2 (EMP2) is found in variety of different cell types and controls cell surface expression and function of specific integrin isoforms. We have previously shown that EMP2 expression correlates with PVR formation. This study looks at the coexpression of EMP2 and other cells markers in pre-retinal membranes. Our purpose was to examine occurrence of different cells types and other key molecules within pre-retinal membranes by looking at expression of Vimentin, VEGF, GFAP, and RPE-65 with respect to EMP2 expression.

 

Methods:

 

Idiopathic and secondary epiretinal membranes were collected from patients during surgical pars plana vitrectomy with consent. The membranes were fixed and processed for paraffin embedding. The membranes were sectioned and protein expression of EMP2, Vimentin, VEGF, GFAP, and RPE-65 was evaluated by immunohistochemical analysis.

 

Results:

 

EMP2 expression was found to vary in pre-retinal membranes of all causes. Vimentin expression was found to be expressed in distinct cell populations separate from EMP2 positive cell populations. In addition, VEGF appeared to be most highly expressed in membranes with low Vimentin expression in all tested membranes. RPE-65 was low in all membranes and was not seen in areas of Vimentin or VEGF expression.

 

Conclusions:

 

Pre-retinal membranes are made up of a variety of different cell types. EMP2 expression along with Vimentin, VEGF and RPE-65 helps depict which of these cells are present. Interestingly, EMP2 appears delineate the RPE cell lineage within the membranes. Better characterization of these membranes will help us understand their pathogenesis, which may lead to the development of new therapeutics.  

 

Keywords: retina • proliferative vitreoretinopathy • immunohistochemistry