Abstract
Purpose: :
To measure the levels of matrix metalloproteinase MMP-2 and MMP-9 in aqueous samples of glaucoma patients on prostaglandin analogue (PA) eye drops compared to a control group of non-glaucoma patients. Altered expression of MMP’s is known to be implicated in glaucoma and PA drugs are believed to control intraocular pressure by remodeling extracellular matrix components in the outflow pathways. We wished to study the effect of PA drops on aqueous levels of MMP 2 and 9.
Methods: :
The study was a prospective, observational, case-control series. Aqueous concentrations of MMP2 and MMP9 were measured in samples from 18 eyes in glaucoma patients on treatment with latanoprost (7), bimatoprost (5) or travoprost (6) and compared to 8 patients who did not have glaucoma. Timolol treatment was also permitted; 4 patients were on timolol and travoprost, 2 on timolol and latanoprost. Aqueous was collected at the time of intraocular surgery (cataract or combined phaco-trabeculectomy) and stored at -80°. Enzyme linked immunosorbent assays (ELISA) were performed in duplicate . Outcome measures were MMP-2 and MMP-9 concentrations in the 3 drug treatment groups of the glaucoma eyes compared to each other and to controls.
Results: :
As determined by ELISA assay, mean MMP-2 levels were 14.4 ± 6.4 in travoprost eyes, 16.7 ± 2.8 in latanoprost eyes ,11.5 ± 3.4 in bimatoprost eyes and 13.4 ± 3.9 in the control group. None of the differences between drug and control, or between different drug groups were statistically significant (p > 0.05 for all comparisons, Student's t-test). The ELISA assay showed MMP-9 levels of 0.52 ± 0.32 in the travoprost eyes, 0.36 ± 0.16 in the latanoprost eyes and 0.26 ± 0.11 in the bimatoprost eyes. The controls showed values of 0.59 ± 0.50 of MMP-9 in the aqueous. None of the differences between drug and control, or between different drug groups were statistically significant (p > 0.05 for all comparisons, Student's t-test).
Conclusions: :
There were no significant differences in the MMP-2 or MMP-9 levels expressed by glaucoma patients on different prostaglandin analog drops compared to normal controls. It is unlikely that the prostaglandin analogues influence IOP via the modulation of levels of MMP-2 & MMP-9.