Abstract
Abstract: :
Purpose:. Protein and peptides in tears play an important role in ocular surface diseases. In previous studies we demonstrated changes in the electrophoretic protein profiles of dry–eye patients. The aim of this work was to determine the usefulness of SELDI–TOF–MS (Surface Enhanced Laser Desorption/Ionisation Time–of–Flight Mass–Spectrometry) ProteinChip® Array technology for the automated analysis of proteins and peptides in tear fluid. Methods: Dry–eye patients (DRY, n=88) and healthy subjects (CTRL, n=71) were examined. Their tear proteins were analyzed using SELDI–TOF–MS ProteinChip Arrays with three different chromatographic surfaces (CM10 cation exchange, Q10 anion exchange, and H50 reverse phase) prepared by means of a laboratory liquid handling robotic workstation. The data were analyzed by multivariate statistical techniques and artificial neural networks and the most important biomarkers purified and then identified by tandem mass spectrometry. Results: Complex patterns of tear proteins and peptides were detected. The different chromatographic surfaces revealed the selective enrichment of proteins such as lipocalin and lysozyme. Analysis of discriminance demonstrated highly significant changes in the protein profiles in dry–eye patients (P<0.001). Using a seven peptide multimarker–panel, an artificial neural network could differentiate between dry–eye and healthy individuals with a specificity and sensitivity of 90%. The identification of biomarkers revealed an increase of inflammatory markers in dry–eye patients and a decrease of some proteins which might have protective functions, such as members of the proline rich protein family. Conclusions:. The SELDI–TOF–MS technology seems to be ideally suitable for the mass–screening of peptides and proteins in tears. This highly sensitive approach dramatically reduces the analysis time and provides protein profiles with great mass accuracy. In this study, new protein biomarkers for dry eye could been demonstrated. Thus, it might become a very useful tool in the search for potential biomarkers for diagnosis and new therapeutics in ocular diseases such as dry–eye.
Keywords: cornea: tears/tear film/dry eye • protein purification and characterization