Cyclo-oxygenase-2 expression in human idiopathic epiretinal membrane.
OBJECTIVE
The purpose of this study was to examine the expression of cyclo-oxygenase (COX)-2 in the idiopathic epiretinal membrane (IERM), inner limiting membrane (ILM), and proliferative diabetic retinopathy membrane.


METHODS
Twenty membranes, consisting of eight IERMs, four ILMs, and eight proliferative diabetic retinopathy membranes, were surgically removed. Formalin-fixed, paraffin-embedded tissue sections were processed for immunohistochemistry using anti-COX-2 antibody. The nuclear density showing the density of cells situated in IERM and ILM specimens was calculated under high-power fields using a light microscope.


RESULTS
The IERM comprised flattened cells with oval nuclei constituting a monolayer. The ILM contained a few cells with abundant collagenous tissues. Neither endothelial nor inflammatory cells were observed in the IERM and ILM. COX-2 immunoreactivity was markedly detected in cells located in the IERM. In contrast, COX-2 immunoreactivity was faintly detected in the ILM. The COX-2-positive rate was 65.4 +/- 15.5% and 34.3 +/- 20.3% in the IERM and ILM, respectively, being significantly higher in the former (P = 0.046). The nuclear density was 39.3 +/- 10.3 and 8.6 +/- 7.2 in the IERM and ILM, respectively, being significantly higher in the former (P = 0.0003). The proliferative diabetic retinopathy membranes consisted of many vascular endothelial and stromal cells. Cytoplasmic immunoreactivity for COX-2 was detected in endothelial and stromal cells in the proliferative diabetic retinopathy membranes.


CONCLUSIONS
These results suggest that COX-2 plays a potential role in the formation of avascular and vascularized epiretinal membranes if an epiphenomenon of COX-2 expression within these epiretinal membranes has been ruled out in future studies.
Kase
Satoru
S
Department of Ophthalmology, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan. kaseron@med.hokudai.ac.jp
Saito
Wataru
W
Ohno
Shigeaki
S
Ishida
Susumu
S
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001485:Basement Membrane / Q000201:enzymology / Q000473:pathology; D002452:Cell Count; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D003930:Diabetic Retinopathy / Q000201:enzymology / Q000473:pathology; D019773:Epiretinal Membrane / Q000201:enzymology* / Q000473:pathology; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged
D051546:Cyclooxygenase 2