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Evaluation of inter-day and inter-individual variability of tear peptide/protein profiles by MALDI-TOF MS analyses

PURPOSE: To characterize the tear film peptidome and low molecular weight protein profiles of healthy control individuals, and to evaluate changes due to day-to-day and individual variation and tear collection methods, by using solid phase extraction coupled to matrix-assisted laser desorption/ioniz...

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Autores principales: González, Nerea, Iloro, Ibon, Durán, Juan A., Elortza, Félix, Suárez, Tatiana
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Molecular Vision 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3380920/
https://www.ncbi.nlm.nih.gov/pubmed/22736947
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author González, Nerea
Iloro, Ibon
Durán, Juan A.
Elortza, Félix
Suárez, Tatiana
author_facet González, Nerea
Iloro, Ibon
Durán, Juan A.
Elortza, Félix
Suárez, Tatiana
author_sort González, Nerea
collection PubMed
description PURPOSE: To characterize the tear film peptidome and low molecular weight protein profiles of healthy control individuals, and to evaluate changes due to day-to-day and individual variation and tear collection methods, by using solid phase extraction coupled to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) profiling. METHODS: The tear protein profiles of six healthy volunteers were analyzed over seven days and inter-day and inter-individual variability was evaluated. The bilaterality of tear film and the effect of tear collection methods on protein profiles were also analyzed in some of these patients. MALDI-TOF MS analyses were performed on tear samples purified by using a solid phase extraction (SPE) method based on C18 functionalized magnetic beads for peptide and low molecular weight protein enrichment, focusing spectra acquisition on the 1 to 20 kDa range. Spectra were analyzed using principal component analysis (PCA) with MultiExperiment Viewer (TMeV) software. Volunteers were examined in terms of tear production status (Schirmer I test), clinical assessment of palpebral lids and meibomian glands, and a subjective OSD questionnaire before tear collection by a glass micro-capillary. RESULTS: Analysis of peptides and proteins in the 1–20 kDa range showed no significant inter-day differences in tear samples collected from six healthy individuals during seven days of monitoring, but revealed subtle intrinsic inter-individual differences. Profile analyses of tears collected from the right and left eyes confirmed tear bilaterality in four healthy patients. The addition of physiologic serum for tear sample collection did not affect the peptide and small protein profiles with respect to the number of resolved peaks, but it did reduce the signal intensity of the peaks, and increased variability. Magnetic beads were found to be a suitable method for tear film purification for the profiling study. CONCLUSIONS: No significant variability in tear peptide and protein profiles below 20 kDa was found in healthy controls over a seven day period, nor in right versus left eye profiles from the same individual. Subtle inter-individual differences can be observed upon tear profiling analysis and confirm intrinsic variability between control subjects. Addition of physiologic serum for tear collection affects the proteome and peptidome in terms of peak intensities, but not in the composition of the profiles themselves. This work shows that MALDI-TOF MS coupled with C18 magnetic beads is an effective and reproducible methodology for tear profiling studies in the clinical monitoring of patients.
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spelling pubmed-33809202012-06-25 Evaluation of inter-day and inter-individual variability of tear peptide/protein profiles by MALDI-TOF MS analyses González, Nerea Iloro, Ibon Durán, Juan A. Elortza, Félix Suárez, Tatiana Mol Vis Research Article PURPOSE: To characterize the tear film peptidome and low molecular weight protein profiles of healthy control individuals, and to evaluate changes due to day-to-day and individual variation and tear collection methods, by using solid phase extraction coupled to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) profiling. METHODS: The tear protein profiles of six healthy volunteers were analyzed over seven days and inter-day and inter-individual variability was evaluated. The bilaterality of tear film and the effect of tear collection methods on protein profiles were also analyzed in some of these patients. MALDI-TOF MS analyses were performed on tear samples purified by using a solid phase extraction (SPE) method based on C18 functionalized magnetic beads for peptide and low molecular weight protein enrichment, focusing spectra acquisition on the 1 to 20 kDa range. Spectra were analyzed using principal component analysis (PCA) with MultiExperiment Viewer (TMeV) software. Volunteers were examined in terms of tear production status (Schirmer I test), clinical assessment of palpebral lids and meibomian glands, and a subjective OSD questionnaire before tear collection by a glass micro-capillary. RESULTS: Analysis of peptides and proteins in the 1–20 kDa range showed no significant inter-day differences in tear samples collected from six healthy individuals during seven days of monitoring, but revealed subtle intrinsic inter-individual differences. Profile analyses of tears collected from the right and left eyes confirmed tear bilaterality in four healthy patients. The addition of physiologic serum for tear sample collection did not affect the peptide and small protein profiles with respect to the number of resolved peaks, but it did reduce the signal intensity of the peaks, and increased variability. Magnetic beads were found to be a suitable method for tear film purification for the profiling study. CONCLUSIONS: No significant variability in tear peptide and protein profiles below 20 kDa was found in healthy controls over a seven day period, nor in right versus left eye profiles from the same individual. Subtle inter-individual differences can be observed upon tear profiling analysis and confirm intrinsic variability between control subjects. Addition of physiologic serum for tear collection affects the proteome and peptidome in terms of peak intensities, but not in the composition of the profiles themselves. This work shows that MALDI-TOF MS coupled with C18 magnetic beads is an effective and reproducible methodology for tear profiling studies in the clinical monitoring of patients. Molecular Vision 2012-06-14 /pmc/articles/PMC3380920/ /pubmed/22736947 Text en Copyright © 2012 Molecular Vision. http://creativecommons.org/licenses/by/3.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Article
González, Nerea
Iloro, Ibon
Durán, Juan A.
Elortza, Félix
Suárez, Tatiana
Evaluation of inter-day and inter-individual variability of tear peptide/protein profiles by MALDI-TOF MS analyses
title Evaluation of inter-day and inter-individual variability of tear peptide/protein profiles by MALDI-TOF MS analyses
title_full Evaluation of inter-day and inter-individual variability of tear peptide/protein profiles by MALDI-TOF MS analyses
title_fullStr Evaluation of inter-day and inter-individual variability of tear peptide/protein profiles by MALDI-TOF MS analyses
title_full_unstemmed Evaluation of inter-day and inter-individual variability of tear peptide/protein profiles by MALDI-TOF MS analyses
title_short Evaluation of inter-day and inter-individual variability of tear peptide/protein profiles by MALDI-TOF MS analyses
title_sort evaluation of inter-day and inter-individual variability of tear peptide/protein profiles by maldi-tof ms analyses
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3380920/
https://www.ncbi.nlm.nih.gov/pubmed/22736947
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