290 - Proteomic analysis in hyperevaporative dry eye patients
Autor(s): P.Versura, P. Nanni, A. Bavelloni, C. Coslovi, G. Cioffi, M. Piazzi, A. Roda, E.C. Campos
Issue: RIMeL - IJLaM, Vol. 5, N. 4, 2009 (MAF Servizi srl ed.)
Page(s): 290-7
Background. The instability of the lachrymal film causesdryness of the eye because of hyperevaporation: theocular surface is not protected and develops epithelialdefects with different degree of severity.
Methods. Five microliters of non-stimulated tears from 50 patients suffering from hyperevaporative dry eye (EDE) and from 15 healthy subjects used as controlhave been collected. Tear proteins such as lysozyme, lactoferrin, lipocalin and lipophilin have been separated by SDS-PAGE electrophoresis using Criterion 20%Bio-Rad gels e Brilliant Blu G (Sigma) staining. Afterwards proteins have been analysed with densitometric techniques vs standard control. The selected gel slides have been characterized by 2D electrophoresis,immunoblotting and enzymatic digestion into peptides with trypsin. The tryptic digests have been analysed by liquid chromatography electrospray ionization Quadrupole-Time of Flight mass spectrometry (LC-ESI QTOF MS/MS) followed by search into NCBI non-redundant protein database using Mascot (MatrixScience, UK). The t-test for independent data andMann-Whitney test for not-paired data (p-value lessthan 0,05) Statistical analyses have been performed onthe results.Results. For all the analysed proteins except lysozyme(p=0,9) a significant variation in the abundance bet-ween diseased patients and controls has been obtai-ned. In particular (data expressed as mean % ± stan-dard deviation): lactoferrin: 8,96 ±3,86 vs 17,41 ±3,46(p=0,001); lipocalin: 7,35 ±1,95 vs 10,55 ±1,01(p=0,002); lipophilin: 3,18 ±1,36 vs 4,14 ±1,25(p=0,01); serum albumin: 9,28 ±6,51 vs 3,49 ±2,35(p=0,005).The proteomic analysis allowed to identify the down-regulation of lipocalin 1 and lipophilin in the diseasedpatients, which is supposed to be associated with post-translational modifications.Conclusions. The decrease in the abundance of lactofer-rin is due to the functional damage of the main lachry-mal gland while the increase of serum albumin is asso-ciated with the exudative phenomenon caused by in-flammation. The decrease of the lipophilic proteinsLipocalin 1 and Lipophilin A and their modification indiseased patients could explain the altered distributionof the lipidic component of the lachrymal film.
Key-words: proteomic, human tears, dry eye.