CD44H localization in primary open-angle glaucoma

PURPOSE. Primary open-angle glaucoma (POAG) is associated with a decreased content of hyaluronan in the trabecular meshwork and in the juxtacanalicular connective tissue. In this study, the authors examined selected regions of the anterior segment to localize and determine the content of CD44H, a transmembrane multifunctional glycoprotein and the principal receptor of hyaluronan. METHODS. Sections of ethanol-fixed anterior segments of six POAG and six normal postmortem eyes were analyzed by immunostaining with and without the nonionic detergent Triton X-100, using the CD44H monoclonal antibody, and the avidin/biotin complex. They were visualized by Vector VIP substrate and were quantitated by computer-aided color image analysis. RESULTS. CD44H was expressed in all regions. Statistically significant decreased content of CD44H was observed in the POAG regions compared with normal regions - ciliary muscle (P < 0.001), ciliary stroma (P < 0.001), anterior iris (P < 0.05), iris root (P < 0.05), and trabecular meshwork (P < 0.05) - and in a subgroup of nonlaser POAG juxtacanalicular connective tissue (P < 0.05) and trabecular meshwork (P < 0.01). In sections treated with Triton X-100 a further increase in immunostaining was observed in normal eyes. As evidenced by scattergram plots of the ciliary body stroma region of the change in the optical density of CD44H between pretreatment with Triton X-100 and without Triton X-100 (γ axis) versus the optical density of CD44H without Triton X-100 (x axis), individual cases of POAG were separated from normals. CONCLUSIONS. These results indicate that CD44H may represent a marker of POAG and an etiologic factor in the POAG disease process.