Effect of latanoprost on the expression of matrix metalloproteinases and tissue inhibitor of metalloproteinase 1 on the ocular surface

Objective: To investigate the effect of topical latanoprost on the expression of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinase 1 (TIMP-1) on the ocular surface. Methods: Tears were collected from 39 patients with glaucoma who used latanoprost, 0.005%, eyedrops (Xalatan) and 28 healthy volunteers. The MMP-9 concentration was measured. Conjunctival epithelial cells were collected from 10 eyes of 10 patients before and 1 to 3 months after starting to take topical latanoprost, 0.005%, and MMP-1, MMP-9, and TIMP-1 messenger RNA (mRNA) expression was analyzed. Both eyes of 48 mice were treated once a day with latanoprost, 0.005%, timolol gel, 0.5%, eyedrops, vehicle of Xalatan, or phosphate-buffered saline, and MMP-9 and TIMP-1 mRNA expression was analyzed. Results: The median MMP-9 concentration in latanoprost-treated cases was 91.2 ng/mL (in controls, 19.7 ng/ mL; P<.001). In latanoprost-treated cases, the relative ratio of MMP-9 to glyceraldehyde 3-phosphate dehydrogenase mRNA was significantly increased from 6.42 to 21.3 (P=.04, paired t test) and the relative amount of TIMP-1 was significantly decreased from 154 to 105 (P=.009). The relative amount of MMP-1 to GAPDH mRNA before and after latanoprost use was not significantly different (P=.16). In mice, MMP-9 expression was increased and TIMP-1 expression was decreased on the ocular surface at 8 weeks after latanoprost use. Conclusion: The topical use of latanoprost increases MMP-1 and MMP-9 and decreases TIMP-1 on the ocular surface. Clinical Relevance: The use of topical latanoprost might not be recommended in patients with keratoconus or after laser-assisted in situ keratomileusis.