Increased expression of serine palmitoyl transferase and ORMDL3 polymorphism are associated with eosinophilic inflammation and airflow limitation in aspirin-exacerbated respiratory disease.

Ga-Young Ban,Dong-Ye Youn,Hae-Sim Park,Young-Min Ye,Olga A Sukocheva

doi:10.1371/journal.pone.0240334

Abstract

BackgroundPatients with aspirin-exacerbated respiratory disease (AERD) are known to have poor clinical outcomes. The pathogenic mechanisms have not yet been completely understood.ObjectiveWe aimed to assess the involvement of the de-novo synthetic pathway of sphingolipid metabolism in patients with AERD compared to those with aspirin tolerant asthma (ATA).MethodsA total of 63 patients with AERD and 79 patients with ATA were enrolled in this study. Analysis of mRNA expression of serine palmitoyl transferase, long-chain base subunit 2 (SPTLC2) and genotyping of ORMDL3 SNP (rs7216389) was performed.ResultsSignificantly higher levels of SPTLC2 mRNA expression were noted in patients with AERD, which showed significant positive correlations with peripheral/sputum eosinophil counts and urine LTE4 (all P<0.05). The levels of SPTLC2 mRNA expression showed significant negative correlations with the level of FEV1 and FEV1/FVC (P = 0.033, r = −0.274; P = 0.019, r = −0.299, respectively). Genotype frequencies of ORMDL3 SNP (rs7216389) showed no significant differences between the AERD and ATA groups. Patients with AERD carrying the TT genotype of ORMDL3 had significantly lower levels of FVC (%) and PC20 methacholine than those carrying the CT or CC genotype (P = 0.026 and P = 0.030).Conclusion & clinical relevanceThis is the first study that shows the dysregulated de novo synthetic pathway of sphingolipids may be involved in the eosinophilic inflammation and airflow limitation in AERD.

Highlights

Asthma is a heterogeneous disease characterized by chronic airway inflammation affecting 1%-18% of the general population worldwide [1]
Higher levels of SPTLC2 mRNA expression were noted in patients with aspirin-exacerbated respiratory disease (AERD), which showed significant positive correlations with peripheral/sputum eosinophil counts and urine leukotriene E4 (LTE4)
This is the first study that shows the dysregulated de novo synthetic pathway of sphingolipids may be involved in the eosinophilic inflammation and airflow limitation in AERD

Summary

Introduction

Asthma is a heterogeneous disease characterized by chronic airway inflammation affecting 1%-18% of the general population worldwide [1]. Airway inflammation is the most important feature of asthma which involves several inflammatory cells including eosinophils, lymphocytes, mast cells, and neutrophils [2]. Aspirin-exacerbated respiratory disease (AERD) is characterized by persistent asthma and chronic rhinosinusitis with nasal polyp as well as aspirin/nonsteroidal anti-inflammatory drug (NSAID) hypersensitivity, where eosinophilia is a common finding in the upper and lower airway mucosa [3]. The risk of uncontrolled asthma, severe asthma and asthma exacerbation is reported to be higher in patients with AERD than in those with aspirin tolerant asthma (ATA) [5]. Patients with aspirin-exacerbated respiratory disease (AERD) are known to have poor clinical outcomes. Flinders University of South Australia, AUSTRALIA Received: June 18, 2020 Accepted: September 23, 2020

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