Blood and Salivary Amphiregulin Levels as Biomarkers for Asthma

Mahmood Yaseen Hachim; Noha Mousaad Elemam; Rakhee K Ramakrishnan; Laila Salameh; Ronald Olivenstein; Ibrahim Yaseen Hachim; Thenmozhi Venkatachalam; Bassam Mahboub; Saba Al Heialy; Rabih Halwani; Qutayba Hamid; Rifat Hamoudi

doi:10.3389/fmed.2020.561866

Blood and Salivary Amphiregulin Levels as Biomarkers for Asthma

Front Med (Lausanne). 2020 Oct 29:7:561866. doi: 10.3389/fmed.2020.561866. eCollection 2020.

Authors

Mahmood Yaseen Hachim^{1

2}, Noha Mousaad Elemam², Rakhee K Ramakrishnan², Laila Salameh³, Ronald Olivenstein⁴, Ibrahim Yaseen Hachim^{2

5}, Thenmozhi Venkatachalam², Bassam Mahboub^{3

5}, Saba Al Heialy^{1

4}, Rabih Halwani^{2

5}, Qutayba Hamid^{2

4

5}, Rifat Hamoudi^{2

5

6}

Affiliations

¹ College of Medicine, Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai, United Arab Emirates.
² Sharjah Institute for Medical Research, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates.
³ Rashid Hospital, Dubai Health Authority, Dubai, United Arab Emirates.
⁴ Meakins-Christie Laboratories, McGill University, Montreal, QC, Canada.
⁵ Department of Clinical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates.
⁶ Division of Surgery and Interventional Science, UCL, London, United Kingdom.

Abstract

Background: Amphiregulin (AREG) expression in asthmatic airways and sputum was shown to increase and correlate with asthma. However, no studies were carried out to evaluate the AREG level in blood and saliva of asthmatic patients. Objective: To measure circulating AREG mRNA and protein concentrations in blood, saliva, and bronchial biopsies samples from asthmatic patients. Methods: Plasma and Saliva AREG protein concentrations were measured using ELISA while PBMCs, and Saliva mRNA expression was measured by RT qPCR in non-severe, and severe asthmatic patients compared to healthy controls. Primary asthmatic bronchial epithelial cells and fibroblasts were assessed for AREG mRNA expression and released soluble AREG in their conditioned media. Tissue expression of AREG was evaluated using immunohistochemistry of bronchial biopsies from asthmatic patients and healthy controls. Publicly available transcriptomic databases were explored for the global transcriptomic profile of bronchial epithelium, and PBMCs were explored for AREG expression in asthmatic vs. healthy controls. Results: Asthmatic patients had higher AREG protein levels in blood and saliva compared to control subjects. Higher mRNA expression in saliva and primary bronchial epithelial cells plus higher AREG immunoreactivity in bronchial biopsies were also observed. Both blood and saliva AREG levels showed positive correlations with allergic rhinitis status, atopy status, eczema status, plasma periostin, neutrophilia, Montelukast sodium use, ACT score, FEV1, and FEV1/FVC. In silico analysis showed that severe asthmatic bronchial epithelium with high AREG gene expression is associated with higher neutrophils infiltration. Conclusion: AREG levels measured in a minimally invasive blood sample and a non-invasive saliva sample are higher in non-allergic severe asthma.

Clinical implications: This is the first report to show the higher level of AREG levels in blood and saliva of non-allergic severe asthma.

Keywords: amphiregulin (AREG); asthma; biomarkers; non-invasive; saliva.