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Proliferative vitreoretinopathy membranes. An immunohistochemical study
J A Jerdan1, J S Pepose, R G Michels
1Wilmer Ophthalmological Institute, Johns Hopkins Medical School, Baltimore, MD.
Abstract:
Proliferative vitreoretinopathy (PVR) is the leading cause of failure after retinal detachment surgery. Therefore, both the extracellular matrix and cellular components of preretinal membranes from 23 eyes with PVR were characterized immunohistochemically. The membrane stroma was composed primarily of types I, II, and III collagen. Laminin and both heparan sulfate proteoglycans and collagens types IV and V were co-distributed in discrete regions within the stroma. Glial and retinal pigment epithelial (RPE) cell populations were identified in these membranes using specific immunohistochemical markers as was a small but significant macrophage population. Double-labeling experiments indicated that RPE cells in these membranes expressed the class II histocompatibility antigen HLA-DR, although neither the RPE monolayer in situ nor cultured RPE cells was HLA-DR positive unless induced by gamma interferon. Only rare isolated vascular endothelial cells were detected in 5 of the 23 membranes.
Insights
Proliferative vitreoretinopathy (PVR) preretinal membranes contain collagen, laminin, and proteoglycans. These membranes also feature glial, RPE, and macrophage cells, with RPE cells expressing HLA-DR.
Area of Science:
- Ophthalmology
- Cell Biology
- Immunology
Background:
- Proliferative vitreoretinopathy (PVR) is a primary cause of retinal detachment surgery failure.
- Understanding the composition of preretinal membranes in PVR is crucial for developing effective treatments.
Purpose of the Study:
- To immunohistochemically characterize the extracellular matrix and cellular components of preretinal membranes in eyes with PVR.
- To identify specific cell types and their expression of markers like HLA-DR.
Main Methods:
- Immunohistochemical analysis of preretinal membranes from 23 eyes with PVR.
- Utilized specific markers to identify collagen types, laminin, proteoglycans, glial cells, RPE cells, macrophages, and vascular endothelial cells.
- Performed double-labeling experiments to assess HLA-DR expression on RPE cells.
Main Results:
- The membrane stroma mainly consisted of collagen types I, II, and III.
- Laminin, heparan sulfate proteoglycans, and collagen types IV and V were found in specific stromal regions.
- Glial cells, retinal pigment epithelial (RPE) cells, and a significant macrophage population were identified.
- RPE cells in membranes expressed HLA-DR, unlike in situ or cultured RPE cells without interferon induction.
- Vascular endothelial cells were rarely detected.
Conclusions:
- Preretinal membranes in PVR are complex structures with diverse cellular and extracellular matrix components.
- The presence and expression of HLA-DR on RPE cells suggest an inflammatory or immune-mediated component in PVR pathogenesis.
- Further research into these components may lead to improved therapeutic strategies for PVR.