The Dry Eye Zone

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Abstract: What's going on behind the scenes in evaporative dry eye

Tear proteomics in evaporative dry eye disease.
Eye (Lond). 2010 Feb 12. [Epub ahead of print]
Versura P, Nanni P, Bavelloni A, Blalock WL, Piazzi M, Roda A, Campos EC.

Ophthalmology Unit, University of Bologna, Bologna, Italy.
Purpose:To analyze tear protein variations in patients suffering from dry eye symptoms in the presence of tear film instability but without epithelial defects.

Methods:Five microlitres of non-stimulated tears from 60 patients, suffering from evaporative dry eye (EDE) with a break-up time (BUT) <10 s, and from 30 healthy subjects as control (no symptoms, BUT >10 s) were collected. Tear proteins were separated by mono and bi-dimensional SDS-PAGE electrophoresis and characterized by immunoblotting and enzymatic digestion. Digested peptides were analyzed by liquid chromatography coupled to electrospray ionization quadrupole-time of flight mass spectrometry followed by comparative data analysis into Swiss-Prot human protein database using Mascot. Statistical analysis were performed by applying a t-test for independent data and a Mann-Whitney test for unpaired data (P<0.05).

Results:In EDE patients vscontrols, a significant decrease in levels of lactoferrin (data in %+/-SD): 20.15+/-2.64 vs24.56+/-3.46 (P=0.001), lipocalin-1: 14.98+/-2.70 vs17.73+/-2.96 (P=0.0001), and lipophilin A-C: 2.89+/-1.06 vs3.63+/-1.37 (P=0.006) was revealed, while a significant increase was observed for serum albumin: 9.45+/-1.87 vs3.46+/-1.87 (P=0.0001). No changes for lysozyme and zinc alpha-2 glycoprotein (P=0.07 and 0.7, respectively) were shown. Proteomic analysis showed a downregulation of lipophilin A and C and lipocalin-1 in patients, which is suggested to be associated with post-translational modifications.

Conclusions:Data show that tear protein changes anticipate the onset of more extensive clinical signs in early stage dry eye disease.Eye advance online publication, 12 February 2010;