Differences in the Histopathology and Matrix Metalloproteinase Expression in Tenon's Tissue of Primary Open-Angle Glaucoma and Primary Angle-Closure Glaucoma

PURPOSE: To investigate the differences in the histopathology and matrix metalloproteinase (MMP) expression in the Tenon's tissue of primary open-angle glaucoma (POAG) patients, primary angle-closure glaucoma (PACG) patients, and non-glaucomatous patients. METHODS: POAG and PACG patients, who underwent a trabeculectomy and had no history of ocular disease except glaucoma, were enrolled. The number and instillation period of topical eye drops were reviewed. For the controls, which were patients without glaucoma or a history of ocular surgery, the Tenon's tissue was obtained in the course of retinal detachment surgery. For glaucoma patients, the Tenon's tissue was obtained during the trabeculectomy. H&E and Masson's trichrome staining and immunohistochemistry for MMP-1, MMP-2, and MMP-9 were performed. A total of six eyes of POAG, six eyes of PACG, and four control eyes were evaluated. RESULTS: The duration of topical anti-glaucoma medication and the mean number of anti-glaucoma medications were similar in the POAG and PACG groups. The levels of MMP-1 and 2 were elevated in the POAG and PACG groups compared to the control group (p=0.03, 0.01, respectively). Compared with the control group, the MMP-2 level was higher in the POAG patients (p=0.01), whereas the MMP-1 was higher in the PACG patients (p=0.04). The levels of MMP-9 in the POAG and PACG patients were not significantly different from that of the control patients (p=0.48, 0.26). The levels of MMP-2 were significantly lower in the PACG patients than in the POAG patients (p=0.02). CONCLUSIONS: The MMP expression was altered in the Tenon's tissue of glaucoma patients compared to the control group. The levels of MMP-2 were lower in the PACG patients than in the POAG patients. These results suggest that there may be histopathological differences in the Tenon's tissue of POAG and PACG patients.