Confounding Patient Factors Affecting the Proper Interpretation of the Periostin Level as a Biomarker in Asthma Development
Received 12 September 2019
Accepted for publication 9 December 2019
Published 8 January 2020 Volume 2020:13 Pages 23—37
Checked for plagiarism Yes
Review by Single-blind
Peer reviewer comments 3
Editor who approved publication: Dr Amrita Dosanjh
Mahmood Yaseen Hachim,1 Noha Mousaad Elemam,1 Rakhee K Ramakrishnan,1 Ibrahim Yaseen Hachim,1 Laila Salameh,1 Bassam Mahboub,1 Saba Al Heialy,2,3 Rabih Halwani,1 Rifat Hamoudi,1 Qutayba Hamid1,2
1Sharjah Institute for Medical Research, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates; 2Meakins-Christie Laboratories, McGill University, Montreal, QC, Canada; 3College of Medicine, Mohammed Bin Rashid University, Dubai, United Arab Emirates
Correspondence: Rifat Hamoudi
College of Medicine, University of Sharjah, PO Box 27272, Sharjah, United Arab Emirates
Introduction: The proper use of serum periostin (POSTN) as a biomarker for asthma is hindered by inconsistent performance in different clinical settings.
Objective: To explore patient’s factors that may affect POSTN expression locally and systematically and its utility as a biomarker for asthma development.
Materials and Methods: Here we used bioinformatics analysis of publicly available transcriptomics data to confirm that POSTN is an asthma specific gene involved in core signaling pathways enriched in the bronchial epithelium during asthma. We then explored a large number of datasets to identify possible confounders that may affect the POSTN gene expression and consequently, its interpretation as a reliable biomarker for asthma. Plasma and saliva levels of POSTN were determined in locally recruited asthmatic patients (mild, moderate and severe) compared to healthy controls to confirm the bioinformatics findings.
Results: Our bioinformatics results confirmed that POSTN was consistently upregulated in the bronchial epithelium in asthma, chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF) bronchial epithelium. In asthma, its mRNA expression was affected by gender, sample anatomical site and type, steroid therapy, and smoking. In our cohort, plasma POSTN was upregulated in severe and non-severe asthmatic patients. Saliva POSTN was significantly higher in non-severe asthmatic patients compared to healthy and severe asthmatic patients (specifically those who are not on Xolair (omalizumab)). Patients’ BMI, inhaled steroid use and Xolair treatment affected POSTN plasma levels.
Conclusion: Up to our knowledge, this is the first study examining the level of POSTN in the saliva of asthmatic patients. Both plasma and saliva POSTN levels can aid in early diagnosis of asthma. Saliva POSTN level was more sensitive than plasma POSTN in differentiating between severe and non-severe asthmatics. Patients’ characteristics like BMI, the use of inhaled steroids, or Xolair treatment should be carefully reviewed before any meaningful interpretation of POSTN level in clinical practice.
Keywords: periostin, biomarkers, transcriptomics
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