Changes in urinary LTE4 and nasal functions following nasal provocation test with ASA in ASA-tolerant and -intolerant asthmatics

Genomics of Treatable Traits in Asthma

The astounding number of genetic variants revealed in the 15 years of genome-wide association studies of asthma has not kept pace with the goals of translational genomics. Moving asthma diagnosis from a nonspecific umbrella term to specific phenotypes/endotypes and related traits may provide insights into features that may be prevented or alleviated by therapeutical intervention. This review provides an overview of the different asthma endotypes and phenotypes and the genomic findings from asthma studies using patient stratification strategies and asthma-related traits. Asthma genomic research for treatable traits has uncovered novel and previously reported asthma loci, primarily through studies in Europeans. Novel genomic findings for asthma phenotypes and related traits may arise from multi-trait and specific phenotyping strategies in diverse populations.

Urinary Leukotriene E4 as a Biomarker in NSAID-Exacerbated Respiratory Disease (N-ERD): a Systematic Review and Meta-analysis

PURPOSE OF REVIEW

Non-steroidal exacerbated respiratory disease (N-ERD) currently requires aspirin challenge testing for diagnosis. Urinary leukotriene E4 (uLTE₄) has been extensively investigated as potential biomarker in N-ERD. We aimed to assess the usefulness of uLTE₄ as a biomarker in the diagnosis of N-ERD.

RECENT FINDINGS

N-ERD, formerly known as aspirin-intolerant asthma (AIA), is characterised by increased leukotriene production. uLTE₄ indicates cysteinyl leukotriene production, and a potential biomarker in N-ERD. Although several studies and have examined the relationship between uLTE₄ and N-ERD, the usefulness of uLTE₄ as a biomarker in a clinical setting remains unclear.

FINDINGS

Our literature search identified 38 unique eligible studies, 35 were included in the meta-analysis. Meta-analysis was performed (i.e. pooled standardised mean difference (SMD) with 95% confidence intervals (95% CI)) and risk of bias assessed (implementing Cochrane Handbook for Systematic Reviews of Diagnostic Test Accuracy (Cochrane DTA)). Data from 3376 subjects was analysed (1354 N-ERD, 1420 ATA, and 602 HC). uLTE₄ was higher in N-ERD vs ATA (n = 35, SMD 0.80; 95% CI 0.72-0.89). uLTE4 increased following aspirin challenge in N-ERD (n = 12, SMD 0.56; 95% CI 0.26-0.85) but not ATA (n = 8, SMD 0.12; CI - 0.08-0.33). This systematic review and meta-analysis showed that uLTE₄ is higher in N-ERD than ATA or HC. Likewise, people with N-ERD have greater increases in uLTE₄ following aspirin challenge. However, due to the varied uLTE₄ measurement and result reporting practice, clinical utility of these findings is limited. Future studies should be standardised to increase clinical significance and interpretability of the results.

Future Horizons in Allergy

There are several advances in diagnosis and management for the otolaryngologist treating allergy. These include new technologies and the refinement of current techniques, and reflect overall trends in health care toward personalized medicine. Local immunoglobulin, urinary leukotriene E4, lipidomics, microRNA within extracellular vesicles, and optical rhinometry all offer to improve the diagnostic accuracy of allergy and related nonallergic conditions. New delivery systems for intranasal steroids and antihistamines, recombinant allergens, advances in allergen immunotherapy delivery, and biologics will improve current management options. These developments will aid the otolaryngologist in diagnosing and treating allergy and related diseases.

Diagnostic Accuracy of Urinary LTE4 Measurement to Predict Aspirin-Exacerbated Respiratory Disease in Patients with Asthma

BACKGROUND

Patients with aspirin-exacerbated respiratory disease (AERD) are distinguished from patients with aspirin-tolerant asthma (ATA) by significantly higher baseline concentrations of urinary leukotriene E₄ (uLTE₄). However, an overlap between the individual values of the groups exists.

OBJECTIVE

The objective of this study was to estimate the discriminative value of uLTE₄ concentration in differentiating between patients with AERD and patients with ATA and evaluate the diagnostic accuracy of uLTE₄ measurement alone and added to clinical parameters to predict AERD diagnosis in patients with asthma.

METHODS

Clinical data were collected from questionnaires. Spirometry, skin prick tests, total IgE, and blood eosinophilia were evaluated. ULTE₄ concentrations were measured in morning urine samples by enzyme-linked immune assay (ELISA).

RESULTS

Patients with AERD (n = 247) had significantly higher uLTE₄ concentrations than those with ATA (n = 239). The uLTE₄ concentration of 800.0 pg/mg creatinine as measured by ELISA on a spot sample best discriminated the 2 groups (area under the curve 0.7; 95% confidence interval 0.66-0.74, sensitivity 49%, specificity 81%). The positive predictive value and negative predictive value (NPV), after considering the prevalence of AERD in the population of asthmatics, were 16% and 96%, respectively. Nasal polyps, upper airway symptoms, nasal corticosteroid treatment, asthma exacerbations, forced expiratory volume in the 1 second predicted, and age of asthma onset were independent predictors of AERD diagnosis. The addition of elevated uLTE₄ concentration to the set of clinical parameters enhanced slightly the prediction of AERD diagnosis beyond the level predicted by clinical parameters (P = .036).

CONCLUSIONS

A set of typical clinical parameters has a superior accuracy in prediction of AERD diagnosis than the measurement of uLTE₄ concentration alone. The addition of uLTE₄ concentration to clinical parameters slightly enhances the prediction of AERD diagnosis, especially due to a high NPV.

An update on the pathogenesis of the upper airways in aspirin-exacerbated respiratory disease

PURPOSE OF REVIEW

The key features of aspirin-exacerbated respiratory diseases (AERDs) include chronic, severe asthma and a high prevalence (60-80%) of chronic rhinosinusitis with nasal polyps, all of which are exacerbated by exposure to aspirin and other NSAIDs. Although the pathogenic mechanisms of AERD are not completely understood, repeated instances have shown intense eosinophilic infiltrations of upper and lower airway mucosa, and dysregulation of arachidonate metabolisms. Here, recent updates on the pathogenic mechanisms of chronic rhinosinusitis with nasal polyps in aspirin-exacerbated respiratory diseases are summarized.

RECENT FINDINGS

Intense eosinophilic infiltration is closely related to the elevated production of cytokines and chemokines such as IL-5 and eotaxin. The response of local immunoglobulin E to staphylococcal enterotoxins contributes to eosinophilic inflammation in nasal polyp tissue. Other characteristics include the overproduction of cysteinyl leukotrienes and increased expression of cysteinyl leukotriene receptor-1, reduced production of prostaglandin E2, and the down-regulation of cyclooxygenase-2 and E-prostanoid receptor subtype-2. A recent gene expression profiling study has also suggested that periostin is the most up-regulated gene in the nasal polyp tissue of AERD patients.

SUMMARY

Chronic rhinosinusitis with nasal polyps is a major comorbid condition of AERD patients that is closely associated with severe asthmatic symptoms. Significant pathologic findings in nasal polyp tissues include intense eosinophilic inflammation, which is caused by elevated production of eosinophil-related cytokines and chemokines, specific immunoglobulin E responses to staphylococcal enterotoxins, and altered arachidonic acid metabolism. This could affect the current treatments and methodologies that are used to control asthma, leading to a more severe and intractable AERD phenotype.

Prostaglandin E2 receptors in asthma and in chronic rhinosinusitis/nasal polyps with and without aspirin hypersensitivity

Chronic rhinosinusitis with nasal polyps (CRSwNP) and asthma frequently coexist and are always present in patients with aspirin exacerbated respiratory disease (AERD). Although the pathogenic mechanisms of this condition are still unknown, AERD may be due, at least in part, to an imbalance in eicosanoid metabolism (increased production of cysteinyl leukotrienes (CysLTs) and reduced biosynthesis of prostaglandin (PG) E2), possibly increasing and perpetuating the process of inflammation. PGE2 results from the metabolism of arachidonic acid (AA) by cyclooxygenase (COX) enzymes, and seems to play a central role in homeostasis maintenance and inflammatory response modulation in airways. Therefore, the abnormal regulation of PGE2 could contribute to the exacerbated processes observed in AERD. PGE2 exerts its actions through four G-protein-coupled receptors designated E-prostanoid (EP) receptors EP1, EP2, EP3, and EP4. Altered PGE2 production as well as differential EP receptor expression has been reported in both upper and lower airways of patients with AERD. Since the heterogeneity of these receptors is the key for the multiple biological effects of PGE2 this review focuses on the studies available to elucidate the importance of these receptors in inflammatory airway diseases.

Allergenicity and toxicology of inhaled silver nanoparticles in allergen-provocation mice models

Silver nanoparticles (AgNP) have been associated with the exacerbation of airway hyperresponsiveness. However, the allergenicity and toxicology of AgNP in healthy and allergic individuals are unclear. We investigated the pathophysiological responses to AgNP inhalation in a murine model of asthma. Continuous and stable levels of 33 nm AgNP were maintained at 3.3 mg/m³ during the experimental period. AgNP exposure concomitant with ovalbumin challenge increased the enhanced pause (Penh) in the control and allergic groups. AgNP evoked neutrophil, lymphocyte and eosinophil infiltration into the airways and elevated the levels of allergic markers (immunoglobulin E [IgE] and leukotriene E₄ [LTE₄]), the type 2 T helper (Th2) cytokine interleukin-13 (IL-13), and oxidative stress (8-hydroxy-2′-deoxyguanosine [8-OHdG]) in healthy and allergic mice. Bronchocentric interstitial inflammation was observed after AgNP inhalation. After inhalation, the AgNP accumulated predominantly in the lungs, and trivial amounts of AgNP were excreted in the urine and feces. Furthermore, the AgNP induced inflammatory responses in the peritoneum. The inhalation of AgNP may present safety concerns in healthy and susceptible individuals.

Rhinosinusitis and nasal polyps in aspirin-exacerbated respiratory disease

The presence of aspirin-exacerbated respiratory disease (AERD) in a patient with chronic rhinosinusitis with nasal polyps and asthma is associated with severe eosinophilic upper and lower airway disease. This article deals with the inflammatory disease of the respiratory tract as it relates to the sinuses. Involvement of the sinuses in AERD is almost universal, depending on the stage of onset of the disease and evaluation by computed tomography. This article explores the clinical aspects, physiopathology, and treatment of rhinosinusitis as it relates to AERD.

Acoustic rhinometry and aspirin nasal challenge in the diagnosis of aspirin-intolerant asthma: clinical finding and safety aspects

BACKGROUND

The safety and utility of nasal provocation tests with lysine-aspirin (L-ASA) in the diagnosis of aspirin-intolerant asthma (AIA) have previously been described in a short series of patients.

OBJECTIVES

To describe the clinical features and safety of an L-ASA challenge test in patients with AIA.

METHODS

We evaluated 72 patients (79% women), with a mean ± SD age of 47.9 ± 14.5 years. All patients were submitted to an L-ASA nasal provocation test (29 mg in each nostril) under acoustic rhinometry (AcR) control. Symptom score (0-3), visual analogical scale and nitric oxide determinations were performed at baseline and at 15, 30, 60 and 90 min. A decrease in nasal volume of at least 25% was considered a positive test. Nasal nitric oxide (nNO) and forced expiratory volume in 1 s were measured.

RESULTS

Nasal congestion and rhinorrhea represented 51 and 32%, respectively, of total symptoms. According to AcR data, the L-ASA challenge test was positive in 20% of patients at 15 min, an additional 36% were positive at 30 min, 18% at 60 min, and the remaining 26% at 90 min. nNO nasal values decreased but did not reach statistical significance. No pulmonary or systemic reactions were observed.

CONCLUSIONS

Symptoms of nasal congestion associated with the reduction in nasal volume measured by AcR are the most useful parameters for establishing the diagnosis of AIA using the L-ASA nasal challenge. The method is very well tolerated and can be safely used even in patients with severe asthma.

[Physiopathology of aspirin intolerant asthma]

Aspirin-exacerbated respiratory disease (AERD) refers to the development of bronchoconstriction in individuals with asthma following the ingestion of aspirin. AERD affects up to 20 % of adults with asthma. At present, no reliable in vitro test is available to confirm the diagnosis. The confirmation of the diagnosis of AERD therefore depends on the response to challenge testing with aspirin. The pathogenesis of AERD is linked to abnormalities in arachidonic acid metabolism. Prior to exposure to aspirin, respiratory mucosal inflammation is the result of a cell infiltration, an overproduction of leukotrienes, prostaglandins D2, 5-oxo-eicosatetraenoic acid and an underproduction of lipoxins. After aspirin ingestion, patients with AERD synthesize excessive amounts of cysteinyl leukotrienes and prostaglandin metabolites involved in bronchoconstriction. New hypotheses concerning AERD pathogenesis have been added to the initial cyclooxygenase theory. These propose that AERD may be linked to the complement system, adenosine metabolism or angiotensin converting enzyme gene and IgE receptor gene polymorphisms.

Diet and asthma

PURPOSE OF REVIEW

The goal of this review is to assess recent additions to the medical literature that contribute to the clinical question: 'How might diet act as a disease modifier in patients with asthma?' In vitro, animal, and epidemiologic data are presented as justification for interventional studies, which form the basis of clinical recommendations and decision-making.

RECENT FINDINGS

A number of studies suggest roles for n-3 fatty acids, soy isoflavones, vitamin D, and antioxidants as modifiers of asthma severity. However, these studies are generally complicated by small sample sizes and either negative results or findings that are of questionable clinical significance.

SUMMARY

The available literature regarding dietary manipulation as asthma therapy is largely unconvincing. Although mechanistic and epidemiologic studies provide a rationale for diet therapies, there are few interventional studies with positive, clinically relevant endpoints. Future studies must include sufficient numbers of well selected patients and measure effects on exacerbations, symptoms, lung function, and medication use.

Aspirin sensitivity and desensitization for asthma and sinusitis

NSAIDs-including aspirin (ASA)-that inhibit cyclooxygenase (COX)-1 induce nonallergic hypersensitivity reactions consisting of attacks of rhinitis and asthma. Such reactions occur exclusively in a subset of asthmatic patients who also have underlying nasal polyps and chronic hyperplastic eosinophilic sinusitis. We now refer to their underlying inflammatory disease of the entire respiratory tract as aspirin-exacerbated respiratory disease. This review focuses on descriptions of these patients; methods available to diagnose ASA-exacerbated respiratory disease; the unique ability of all NSAIDs that inhibit COX-1 to cross-react with ASA; lack of cross-reactivity with selective COX-2 inhibitors; an update on pathogenesis; and current thoughts about treatment, including ASA desensitization and daily ingestion of ASA itself.

Control of salicylate intolerance with fish oils

We report three patients with disabling salicylate-induced intolerance who experienced abrogation of symptoms following dietary supplementation with omega-3 polyunsaturated fatty acids (PUFAs). All three patients experienced severe urticaria, asthma requiring systemic steroid therapy and anaphylactic reactions. After dietary supplementation with 10 g daily of fish oils rich in omega-3 PUFAs for 6-8 weeks all three experienced complete or virtually complete resolution of symptoms allowing discontinuation of systemic corticosteroid therapy. Symptoms relapsed after dose reduction. Fish oil appears a safe and effective treatment for this difficult and often serious condition.

Aspirin-exacerbated asthma

: This review focuses on aspirin-exacerbated asthma (AEA). The review includes historical perspective of aspirin, prevalence, pathogenesis, clinical features and treatment of AEA. The pathogenesis of AEA involves the cyclooxygenase and lipooxygenase pathway. Aspirin affects both of these pathways by inhibiting the enzyme cycooxygenase-1 (COX-1). Inhibition of COX-1 leads to a decrease in prostaglandin E2 (PGE2). The decrease in PGE2 results in an increase in cysteinyl leukotrienes by the lipooxygenase pathway involving the enzyme 5-lipooxygenase (5-LO). Leukotriene C4 (LTC4) synthase is the enzyme responsible for the production of leukotriene C4, the chief cysteinyl leukotriene responsible for AEA. There have been familial occurences of AEA. An allele of the LTC4 synthase gene in AEA is known as allele C. Allele C has a higher frequency in AEA. Clinical presentation includes a history of asthma after ingestion of aspirin, nasal congestion, watery rhinorrhea and nasal polyposis. Treatment includes leukotriene receptor antagonists, leukotriene inhibitors, aspirin desinsitaztion and surgery. AEA is the most well-defined phenotype of asthma. Although AEA affects adults and children with physician-diagnosed asthma, in some cases there is no history of asthma and AEA often goes unrecognized and underdiagnosed.