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Epithelial Membrane Protein-2 in Human Proliferative Vitreoretinopathy and Epiretinal Membranes
David G Telander1, Alfred K Yu1, Krisztina I Forward1
1Department of Ophthalmology University of California, Davis, Sacramento, California, United States.
Purpose:
To determine the level of epithelial membrane protein-2 (EMP2) expression in preretinal membranes from surgical patients with proliferative vitreoretinopathy (PVR) or epiretinal membranes (ERMs). EMP2, an integrin regulator, is expressed in the retinal pigment epithelium and understanding EMP2 expression in human retinal disease may help determine whether EMP2 is a potential therapeutic target.
Methods:
Preretinal membranes were collected during surgical vitrectomies after obtaining consents. The membranes were fixed, processed, sectioned, and protein expression of EMP2 was evaluated by immunohistochemistry. The staining intensity (SI) and percentage of positive cells (PP) in membranes were compared by masked observers. Membranes were categorized by their cause and type including inflammatory and traumatic.
Results:
All of the membranes stained positive for EMP2. Proliferative vitreoretinopathy-induced membranes (all causes) showed greater expression of EMP2 than ERMs with higher SI (1.81 vs. 1.38; P = 0.07) and PP (2.08 vs. 1.54; P = 0.09). However all the PVR subgroups had similar levels of EMP2 expression without statistically significant differences by Kruskal-Wallis test. Inflammatory PVR had higher expression of EMP2 than ERMs (SI of 2.58 vs. 1.38); however, this was not statistically significant. No correlation was found between duration of PVR membrane and EMP2 expression. EMP2 was detected by RT-PCR in all samples (n = 6) tested.
Conclusions:
All studied ERMs and PVR membranes express EMP2. Levels of EMP2 trended higher in all PVR subgroups than in ERMs, especially in inflammatory and traumatic PVR. Future studies are needed to determine the role of EMP2 in the pathogenesis and treatment of various retinal conditions including PVR.
Insights
Epithelial membrane protein-2 (EMP2) is expressed in preretinal membranes from patients with epiretinal membranes (ERMs) and proliferative vitreoretinopathy (PVR). EMP2 levels trended higher in PVR membranes, suggesting a potential therapeutic role.
Area of Science:
- Ophthalmology
- Molecular Biology
- Cell Biology
Background:
- Epithelial membrane protein-2 (EMP2) is an integrin regulator.
- EMP2 is expressed in the retinal pigment epithelium.
- Understanding EMP2 expression in retinal diseases is crucial for identifying therapeutic targets.
Purpose of the Study:
- To quantify epithelial membrane protein-2 (EMP2) expression in preretinal membranes.
- To compare EMP2 levels in membranes from patients with proliferative vitreoretinopathy (PVR) and epiretinal membranes (ERMs).
- To assess EMP2 as a potential therapeutic target in retinal diseases.
Main Methods:
- Preretinal membranes were obtained from surgical vitrectomies.
- Immunohistochemistry was used to evaluate EMP2 protein expression.
- Staining intensity and percentage of positive cells were compared between membrane types.
Main Results:
- All examined membranes (ERMs and PVR) showed positive EMP2 expression.
- EMP2 levels trended higher in PVR membranes compared to ERMs.
- No correlation was found between PVR duration and EMP2 expression.
Conclusions:
- Epithelial membrane protein-2 (EMP2) is present in both ERM and PVR membranes.
- Elevated EMP2 expression in PVR suggests its potential involvement in disease pathogenesis.
- Further research is warranted to explore EMP2's role in retinal conditions and therapeutic strategies.
