Evaluation of pre-processing methods for tear fluid proteomics using proximity extension assays

Daphne P.C. Vergouwen*, Amber J. Schotting, Tanja Endermann, Harmen J.G. van de Werken, Dwin G.B. Grashof, Sinthuja Arumugam, Rudy M.M.A. Nuijts, Josianne C. ten Berge, Aniki Rothova, Marco W.J. Schreurs, Marlies Gijs

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

2 Citations (Scopus)
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Tear fluid forms a potential source for biomarker identification, and can be minimal invasively collected via Schirmer strips. The lack of knowledge on the processing of Schirmer strips however complicates the analysis and between-study comparisons. We studied two different pre-processing methods, specifically the use of punches of the strip versus elution of the strip in a buffer. Tear fluid filled Schirmer strips were collected from 5 healthy participants, and divided into two halves over the length of the strip. In either part, punches or eluates were obtained from 4 different locations, from the first part touching the eye (head) to the end, to assess the protein distribution along the strips. The levels of 92 inflammatory proteins were measured in the punches/eluates using proximity extension assays. The punch method yielded higher protein detectability compared to the elution method (76% vs 66%; p ≤ 0.001). Protein expression level was found to be slightly higher in the head of the strip, however, 3 out of 5 punches from the head failed quality control. Protein expression levels over the remaining parts of the strips were similar. Our study showed beneficial use of punches of any part of the strip except the head in future biomarker research.

Original languageEnglish
Article number4433
JournalScientific Reports
Issue number1
Publication statusPublished - 17 Mar 2023

Bibliographical note

Funding Information:
This study was funded by Stichting Lijf en Leven under Grant [number L&L/mon/19-007].

Publisher Copyright:
© 2023, The Author(s).


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