Biomarkers for predicting response to aspirin therapy in aspirin-exacerbated respiratory disease

Accumulation of long-chain unsaturated fatty acids in the airway inflammatory microenvironment drives eosinophil etosis and corticosteroid resistance

BACKGROUND

Eosinophilic inflammation is a feature of chronic rhinosinusitis with nasal polyps (CRSwNP). Patients with eosinophilic CRSwNP (ENP) tend to be refractory and prone to recurrence. Although there is increasing evidence linking lipid metabolic irregularities to eosinophilia, the particular lipid responsible for promoting eosinophilic inflammation and the precise molecular mechanisms involved remain unclear.

METHODS

Lipidomic atlas and metabolic pathway enrichment were identified by liquid chromatography-tandem mass spectrometry and RNA sequencing, respectively. Eosinophil extracellular trap cell death (EETosis) was detected by immunofluorescence microscopy and transmission electron microscopy. Functional analyses were performed on purified eosinophils.

RESULTS

The unbiased lipidomic atlas identified a specific accumulation in long-chain fatty acids (LCFAs) in ENP. Consistently, RNA-seq analysis confirmed the enrichment in long-chain unsaturated fatty acid metabolism pathway in ENP. In this lipid-rich airway inflammatory environment, EETosis including ETotic eosinophils, EETs release and Charcot-Leyden crystals (CLCs) generation was enhanced in ENP, and associated with disease severity. Further, we found that both saturated and unsaturated LCFAs, such as arachidonic acid, are critical fuel sources to trigger eosinophil activation and filamentous DNA release, whereas only arachidonic acid could induce crystalline Galectin10 (CLCs). Mechanistically, arachidonic acid induces EETosis through a mechanism independent of reactive oxygen species but the IRE1α/XBP1s/PAD4 pathway. Both the long-acting dexamethasone and short-acting hydrocortisone, while facilitate eosinophil apoptosis, are ineffective to block arachidonic acid-induced EETosis.

CONCLUSIONS

Our findings demonstrate a previously unknown role of the LCFA arachidonic acid in mediating EETosis and glucocorticoid insensitivity to drive ENP progression, which may lead to novel insights regarding the treatment of patients with refractory eosinophilic inflammation.

Clinical and mechanistic advancements in aspirin exacerbated respiratory disease

Aspirin-exacerbated respiratory disease (AERD) is characterized by the clinical triad of chronic rhinosinusitis with nasal polyps, asthma, and a hypersensitivity to nonsteroidal anti-inflammatory drugs (NSAIDs). AERD is estimated to occur in as many as 15% of patients with chronic rhinosinusitis with nasal polyps and/or asthma. Uniquely, patients with AERD develop respiratory symptoms within 30 to 180 minutes after ingesting NSAIDs such as aspirin or ibuprofen. However, even in the absence of NSAIDs, patients tend to have more severe upper and lower respiratory disease. The underlying pathogenic mechanisms contributing to AERD are complex and intertwined; they include a systemic dysregulation in arachidonic acid metabolism, an aberrant inflammatory response, a disruption in the respiratory epithelial barrier, and an imbalance between the formation and degradation of fibrin locally in nasal polyps. This review will highlight novel mechanistic findings contributing to the pathogenesis of AERD. In addition, recent advancements in the clinical understanding and management of patients with AERD will be discussed.

Aspirin hypersensitivity diagnostic index (AHDI): In vitro test for diagnosing of N-ERD based on urinary 15-oxo-ETE and LTE4 excretion

BACKGROUND

15-oxo-eicosatetraenoic acid (15-oxo-ETE), is a product of arachidonic acid (AA) metabolism in the 15-lipoxygenase-1 (15-LOX-1) pathway. 15-oxo-ETE was overproduced in the nasal polyps of patients with nonsteroidal anti-inflammatory drug-exacerbated respiratory disease (N-ERD). In this study we investigated the systemic biosynthesis of 15-oxo-ETE and leukotriene E4 (LTE4) and assessed their diagnostic value to identify patients with N-ERD.

METHODS

The study included 64 patients with N-ERD, 59 asthmatics who tolerated aspirin well (ATA), and 51 healthy controls. A thorough clinical characteristics of asthmatics included computed tomography of paranasal sinuses. Plasma and urinary 15-oxo-ETE levels, and urinary LTE4 excretion were measured using high-performance liquid chromatography and tandem mass spectrometry. Repeatability and precision of the measurements were tested.

RESULTS

Plasma 15-oxo-ETE levels were the highest in N-ERD (p < .001). A receiver operator characteristic (ROC) revealed that 15-oxo-ETE had certain sensitivity (64.06% in plasma, or 88.24% in urine) for N-ERD discrimination, while the specificity was rather limited. Modeling of variables allowed to construct the Aspirin Hypersensitivity Diagnostic Index (AHDI) based on urinary LTE4-to-15-oxo-ETE excretion corrected for sex and the Lund-Mackay score of chronic rhinosinusitis. AHDI outperformed single measurements in discrimination of N-ERD among asthmatics with an area under ROC curve of 0.889, sensitivity of 81.97%, specificity of 87.23%, and accuracy of 86.87%.

CONCLUSIONS

We confirmed 15-oxo-ETE as a second to cysteinyl leukotrienes biomarker of N-ERD. An index based on these eicosanoids corrected for sex and Lund-Mackay score has a similar diagnostic value as gold standard oral aspirin challenge in the studied group of patients with asthma.

Unique effect of aspirin on local 15-oxo-eicosatetraenoic acid synthesis in asthma patients with aspirin hypersensitivity

BACKGROUND

Nonsteroidal anti-inflammatory drugs-exacerbated respiratory disease (NSAIDs-ERD) is characterized by altered arachidonic acid (AA) metabolism. Aspirin hypersensitivity is diagnosed using aspirin challenge, while induced sputum is collected to perform cell counts and to identify local biomarkers in induced sputum supernatant (ISS). This study aimed to assess the levels of a newly identified eicosanoid, 15-oxo-eicosatetraenoic acid (15-oxo-ETE), in ISS at baseline and during aspirin-induced bronchospasm in patients with NSAIDs-ERD.

METHODS

Oral aspirin challenge was performed in 27 patients with NSAIDs-ERD and in 17 patients with aspirin-tolerant asthma (ATA) serving as controls. Sputum was collected before and after aspirin challenge to determine eosinophil, neutrophil, macrophage, and lymphocyte counts as well as the concentration of AA metabolites via 15-lipoxygenase-1 (15-LOX-1) and 5-LOX pathways in ISS. Chromatography-tandem mass spectrometry was used to measure ISS levels of 15-oxo-ETE, 15-hydroxyeicosatetranoic acid (15-HETE), and leukotriene E4 (LTE4).

RESULTS

At baseline, ISS levels of 15-oxo-ETE were higher in NSAIDs-ERD than in ATA (p = 0.04). In contrast, baseline 15-HETE levels in ISS were lower in patients with NSAIDs-ERD (p = 0.03). After aspirin challenge, 15-oxo-ETE levels decreased only in patients with NSAIDs-ERD (p = 0.001) who developed bronchospasm. In both study groups, there was a reduction in sputum macrophage count after aspirin challenge (p = 0.03 and p = 0.02, respectively) irrespective of bronchospasm.

CONCLUSIONS

Patients with NSAIDs-ERD are characterized by higher baseline 15-oxo-ETE levels in ISS than patients with ATA. Aspirin-induced bronchospasm inhibited the local generation of 15-oxo-ETE.

Mechanistic and clinical updates in AERD: 2021-2022

Aspirin-exacerbated respiratory disease (AERD) is a unique and often clinically severe disease affecting a subgroup of adults with asthma and chronic rhinosinusitis with nasal polyposis. Works published in 2021-2022 confirmed the critical role of lipid mediator dysregulation and mast cell activation and expanded our understanding of basophils, macrophages, fibrin dysregulation, and the 15-lipoxygenase pathway in disease pathogenesis. Translational studies established inflammatory heterogeneity in the upper and lower airway at baseline and during aspirin-induced respiratory reactions. Clinical cohorts provided insights into the mechanistic actions of frequently utilized biologic therapies in AERD. These advances are already changing clinical care delivery and affecting patient outcomes. Despite this, further work is needed to improve clinical tools to reliably diagnose AERD and identify factors that could prevent development of the disease altogether. Additionally, the impact of inflammatory heterogeneity on clinical trajectories and the utility and safety of combination biologic and daily aspirin therapies remains unanswered.

Non-eosinophilic asthma in nonsteroidal anti-inflammatory drug exacerbated respiratory disease

BACKGROUND

The cellular inflammatory pattern of nonsteroidal anti-inflammatory drug-exacerbated respiratory disease (N-ERD) is heterogeneous. However, data on the heterogeneity of non-eosinophilic asthma (NEA) with aspirin hypersensitivity are scanty. By examination of N-ERD patients based on clinical data and eicosanoid biomarkers we aimed to identify NEA endotypes potentially guiding clinical management.

METHODS

Induced sputum was collected from patients with N-ERD. Sixty six patients (49.6% of 133 N-ERD) with NEA were included in the hierarchical cluster analysis based on clinical and laboratory data. The quality of clustering was evaluated using internal cluster validation with different indices and a practical decision tree was proposed to simplify stratification of patients.

RESULTS

The most frequent NEA pattern was paucigranulocytic (PGA; 75.8%), remaining was neutrophilic asthma (NA; 24.2%). Four clusters were identified. Cluster #3 included the highest number of NEA patients (37.9%) with severe asthma and PGA pattern (96.0%). Cluster #1 (24.2%) included severe only asthma, with a higher prevalence of NA (50%). Cluster #2 (25.8%) comprised well-controlled mild or severe asthma (PGA; 76.5%). Cluster #4 contained only 12.1% patients with well-controlled moderate asthma (PGA; 62.5%). Sputum prostaglandin D2 levels distinguished cluster #1 from the remaining clusters with an area under the curve of 0.94.

CONCLUSIONS

Among identified four NEA subtypes, clusters #3 and #1 represented N-ERD patients with severe asthma but a different inflammatory signatures. All the clusters were discriminated by sputum PGD2 levels, asthma severity, and age of patients. The heterogeneity of non-eosinophilic N-ERD suggests a need for novel targeted interventions.

SNOT-22 scores after 6 months of aspirin therapy are predictive of long-term quality of life in AERD

Background: Aspirin exacerbated respiratory disease (AERD) is an inflammatory condition that consists of eosinophilic asthma, chronic rhinosinusitis with nasal polyps, and respiratory reactions to cyclooxygenase-1 inhibitors. Aspirin therapy after aspirin desensitization (ATAD) is the most extensively studied treatment paradigm for AERD. Objective: The objective was to identify which time point of ATAD was most predictive of long-term outcomes as measured by the 22-item Sino-Nasal Outcome Test (SNOT-22). Methods: A retrospective chart review was conducted of patients at a single institution who underwent endoscopic sinus surgery, followed by ATAD, and had remained on ATAD for 2 consecutive years. SNOT-22 scores were recorded at predesensitization as well as at the 3-, 6-, 12-, and 24-month postdesensitization time points. The patients were separated into two cohorts at each of the data collection time points based on whether their SNOT-22 scores were < 20 (responders) or ≥ 20 (nonresponders). Responder status was compared between each time point and at 24-month postdesensitization. The odds ratios (OR) were then calculated between the two groups at each of the following time points: postsurgery/predesensitization, and 3-, 6-, and 12-month postdesensitization. Results: There were 70 patients who met the inclusion criteria of having 24-month postdesensitization SNOT-22 scores available. Responder status at 6 months after surgery had the most predictive OR 16.5 (95% confidence interval, 3.71-73.44) for long-term outcomes at 24 months. Conclusion: The SNOT-22 scores after 6 months of ATAD showed the greatest predictive value for long-term quality-of-life outcomes and, therefore, poor 6-month SNOT-22 scores could serve as a basis for consideration of alternative therapies.

Comprehensive Analysis of Nasal Polyps Reveals a More Pronounced Type 2 Transcriptomic Profile of Epithelial Cells and Mast Cells in Aspirin-Exacerbated Respiratory Disease

Chronic rhinosinusitis with nasal polyps is affecting up to 3% of Western populations. About 10% of patients with nasal polyps also suffer from asthma and intolerance to aspirin, a syndrome called aspirin-exacerbated respiratory disease. Although eosinophilic inflammation is predominant in polyps of both diseases, phenotypic differences in the tissue-derived microenvironment, elucidating disease-specific characteristics, have not yet been identified. We sought to obtain detailed information about phenotypic and transcriptional differences in epithelial and immune cells in polyps of aspirin-tolerant and intolerant patients. Cytokine profiles in nasal secretions and serum of patients suffering from aspirin-exacerbated respiratory disease (n = 10) or chronic rhinosinusitis with nasal polyps (n = 9) were assessed using a multiplex mesoscale discovery assay. After enrichment for immune cell subsets by flow cytometry, we performed transcriptomic profiling by employing single-cell RNA sequencing. Aspirin-intolerant patients displayed significantly elevated IL-5 and CCL17 levels in nasal secretions corresponding to a more pronounced eosinophilic type 2 inflammation. Transcriptomic profiling revealed that epithelial and mast cells not only complement one another in terms of gene expression associated with the 15-lipoxygenase pathway but also show a clear type 2-associated inflammatory phenotype as identified by the upregulation of POSTN, CCL26, and IL13 in patients with aspirin-exacerbated respiratory disease. Interestingly, we also observed cellular stress responses indicated by an increase of MTRNR2L12, MTRNR2L8, and NEAT1 across all immune cell subsets in this disease entity. In conclusion, our findings support the hypothesis that epithelial and mast cells act in concert as potential drivers of the pathogenesis of the aspirin-exacerbated respiratory disease.

A retrospective study on long-term efficacy of intranasal lysine-aspirin in controlling NSAID-exacerbated respiratory disease

Purpose

Aspirin treatment after desensitization (ATAD) represents an effective therapeutic option suitable for NSAID-exacerbated respiratory disease (N-ERD) patients with recalcitrant disease. Intranasal administration of lysine-aspirin (LAS) has been suggested as a safer and faster route than oral ATAD but evidence for its use is less strong. We investigated nasal LAS therapy long-term efficacy based on objective outcomes, smell function, polyp recurrence and need for surgery or rescue therapy. Clinical biomarkers predicting response to intranasal LAS, long-term side effects and consequences of discontinuing treatment have been evaluated.

Methods

A retrospective analysis of a database of 60 N-ERD patients seen between 2012 and 2020 was performed in March 2021. They were followed up at 3-months, 1-, 2- and 3-years with upper and lower airway functions assessed at each follow-up.

Results

Higher nasal airflow and smell scores were found at each follow-up in patients taking LAS (p < 0.001 and p = 0.048 respectively). No influence of LAS on pulmonary function measurements was observed. Patient on intranasal LAS showed a lower rate of revision sinus surgery when compared to those who discontinued the treatment (p < 0.001). None of the variables studied was found to influence LAS treatment response.

Conclusion

Our study demonstrates the clinical effectiveness of long-term intranasal LAS in the management of N-ERD in terms of improved nasal airflow and olfaction and a reduced need for revision sinus surgery. Intranasal LAS is safe, being associated with a lower rate of side effects when compared to oral ATAD. However, discontinuation of the treatment at any stage is associated with a loss of clinical benefit.

Biomarkers for predicting response to long-term high dose aspirin therapy in aspirin-exacerbated respiratory disease

INTRODUCTION

Aspirin-exacerbated respiratory disease (AERD) is a phenotype of asthma characterized by eosinophilic inflammation in the airways, mast cell activation, cysteinyl leukotriene overproduction, and acute respiratory reactions on exposure to cyclooxygenase-1 inhibitors. Aspirin desensitization followed by daily high-dose aspirin therapy is a safe and effective treatment option for the majority of patients with AERD. However, there is still some percentage of the population who do not derive benefits from daily aspirin use.

METHODS

Based on the current literature, the biomarkers, which might predict aspirin treatment outcomes in AERD patients, were evaluated.

RESULTS AND CONCLUSIONS

Patients with severe symptoms of chronic rhinosinusitis, type 2 asthma based on blood eosinophilia, non-neutrophilic inflammatory phenotype based on sputum cells, as well as high plasma level of 15-hydroxyeicosatetraenoic acid (15-HETE) are potentially good responders to long term high-dose aspirin therapy. Additionally, high expression of the hydroxyprostaglandin dehydrogenase gene, HPGD encoding prostaglandin-degrading enzyme 15-hydroxyprostaglandin dehydrogenase (15-PGDH) and low expression of the proteoglycan 2 gene, PRG2 encoding constituent of the eosinophil granule in sputum cells might serve as a predictor of good response to aspirin therapy. Variations in the expression of cysteinyl leukotriene receptor 1 in the airways could additionally influence the response to long-term aspirin therapy. Arachidonic acid metabolites levels via the 5-lipoxygenase as well as via the cyclooxygenase pathways in induced sputum supernatant do not change during high dose long-term aspirin therapy and do not influence outcomes of aspirin treatment.