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Abstract #18332 Published in IGR 3-3
Expression of cyclooxygenase-1 and -2 in normal and glaucomatous human eyes
Maihöfner C; Schlötzer-Schrehardt U; Gübring H; Zeilhofer HU; Naumann GOH; Pahl A; Mardin CY; Tamm ER; Brune KInvestigative Ophthalmology and Visual Science 2001; 42: 2616-2624
PURPOSE: Primary open-angle glaucoma (POAG) is the predominant form of chronic glaucoma, but the underlying pathological 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 (POAG, angle-closure, congenital juvenile, and steroid-induced), as well as in age-matched control eyes. Additionally, PGE2 was measured in the 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 was 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 a 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 that was indistinguishable from control eyes. The 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 lined to the occurrence of POAG and steroid-induced glaucoma.
Dr K. Brune, Department of Experimental and Clinical Pharmacology and Toxicology, University of Erlangen-Nürnberg, Fahrstrasse 17, D91051 Erlangen, Germany. kaybrune@pharmakologie.uni-erlangen.de
Classification:
11.14 Investigational drugs; pharmacological experiments (Part of: 11 Medical treatment)
