Proteomic profiling of inflammatory signaling molecules in the tears of patients on chronic glaucoma medication.
To uncover tear proteins associated with the chronic use of glaucoma medication using proteomic analysis, and to compare these proteins to those previously identified from primary dry eye disease.
Eighteen patients treated with topical anti-glaucoma medications and 10 normal age-matched subjects with no prior topical treatment were recruited for the study. Tears were collected usingSchirmer's strip and analyzed using iTRAQ for the tear proteins using mass spectrometry. Conjunctival samples were collected and RNA expression determined by PCR.
Of the 124 identified tear proteins (99% confidence, ProtScore ≥ 2.0), we found that the tear levels of S100A8, A9, mammaglobinB and 14-3-3 ζ/δ were significantly increased in the medicated group compared to non-medicated group, (P<0.05). For S100 A9, mammaglobin B and 14-3-3 ζ/δ, use of topical medication for less than 1 year did not reach statistical significance compared to non-medicated group. Eyes on topical medication for less than one year showed a decrease of proline-rich 4 protein tear level (p = 0.0049) compared to non-medicated group. The tear proteins detected in the medicated group differed from the primary dry eye group.
Duration of topical anti-glaucoma medications longer than one year may start to induce ocular surface inflammation. The inflammatory tear protein profile present in chronically medicated glaucoma eyes appears to be different to that found in primary dry eye. Identification of tear proteins specific to medicated glaucoma eyes will help to specifically develop targeted screening modalities and therapeutic agents different to current conventional dry eye management.
Invest Ophthalmol Vis Sci. 2011 Jun 22. [Epub ahead of print]
Wong TT, Zhou L, Li J, Tong L, Zhao SZ, Li XR, Yu SJ, Koh SK, Beuerman RW.
Singapore Eye Research Institute, Singapore.