title: Expression of cyclooxygenase-1 and -2 in normal and glaucomatous human eyes.
abstract: OBJECTIVE
  Primary open-angle glaucoma (POAG) is the predominant form of chronic glaucoma, but the underlying pathologic mechanisms are largely unknown. Because prostaglandins (PGs) have been introduced into POAG treatment with remarkable success, this study was undertaken to investigate whether a change in the expression of the PG-synthesizing enzymes cyclooxygenase (COX)-1 and -2 might be involved in the pathogenesis of POAG.
  
  
  METHODS
  Expression of COX-1 and -2 was assessed by confocal laser microscopy, immunohistochemistry, Western blot analysis, and real-time RT-PCR in human eyes with different forms of glaucoma (primary open-angle, angle-closure, congenital juvenile, and steroid-induced), as well as in age-matched control eyes. Additionally, PGE2 was measured in aqueous humor by means of an enzyme-linked immunoassay as a product of COX activity.
  
  
  RESULTS
  In normal eyes, ocular COX-1 and -2 expression were largely confined to the nonpigmented secretory epithelium of the ciliary body. By immunohistochemistry and real-time RT-PCR, COX-2 expression was completely lost in the nonpigmented secretory epithelium of the ciliary body of eyes with end-stage POAG, whereas COX-1 expression was unchanged. By immunohistochemistry, in the ciliary bodies of eyes in five patients with diagnosis of early POAG, eyes in two had complete loss of COX-2 expression and in three showed only a few remaining scattered COX-2-expressing cells. COX-2 expression in the ciliary body was also lost in patients with steroid-induced glaucoma and was reduced in patients receiving topical steroid treatment. Eyes of patients with either congenital juvenile or angle-closure glaucoma showed COX-2 expression indistinguishable from control eyes. Aqueous humor of eyes with POAG contained significantly less PGE2 than control eyes.
  
  
  CONCLUSIONS
  Both cyclooxygenase isoforms are constitutively expressed in the normal human eye. Specific loss of COX-2 expression in the nonpigmented secretory epithelium of the ciliary body appears to be linked to the occurrence of POAG and steroid-induced glaucoma.
authors.affiliation: Department of Experimental and Clinical Pharmacology and Toxicology, University of Erlangen-Nürnberg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Maihöfner
authors.forename: U
authors.initials: U
authors.lastname: Schlötzer-Schrehardt
authors.forename: H
authors.initials: H
authors.lastname: Gühring
authors.forename: H U
authors.initials: HU
authors.lastname: Zeilhofer
authors.forename: G O
authors.initials: GO
authors.lastname: Naumann
authors.forename: A
authors.initials: A
authors.lastname: Pahl
authors.forename: C
authors.initials: C
authors.lastname: Mardin
authors.forename: E R
authors.initials: ER
authors.lastname: Tamm
authors.forename: K
authors.initials: K
authors.lastname: Brune
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001082:Aqueous Humor / Q000378:metabolism; D015153:Blotting, Western; D002924:Ciliary Body / Q000201:enzymology*; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D015232:Dinoprostone / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D004847:Epithelial Cells / Q000201:enzymology; D019084:Fluorescent Antibody Technique, Indirect; D015812:Glaucoma, Angle-Closure / Q000201:enzymology*; D005902:Glaucoma, Open-Angle / Q000201:enzymology*; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins; D018613:Microscopy, Confocal; D016253:Microscopy, Immunoelectron; D008875:Middle Aged; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics / Q000378:metabolism*; D012313:RNA / Q000302:isolation & purification; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D007527:Isoenzymes; D008565:Membrane Proteins; D012333:RNA, Messenger; D012313:RNA; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; C496511:PTGS1 protein, human; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone