Nasal versus bronchial and nasal response to oral aspirin challenge: Clinical and biochemical differences between patients with aspirin-induced asthma/rhinitis

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.

Genetic Variants Leading to Urticaria and Angioedema and Associated Biomarkers

Advances in next generation sequencing technologies, as well as their expanded accessibility and clinical use over the past 2 decades, have led to an exponential increase in the number of identified single gene disorders. Among these are primary atopic disorders-inborn errors of immunity resulting in severe allergic phenotypes as a primary presenting feature. Two cardinal aspects of type I immediate hypersensitivity allergic reactions are hives and angioedema. Mast cells (MCs) are frequent primary drivers of these symptoms, but other cells have also been implicated. Even where MC degranulation is believed to be the cause, mediator-induced symptoms may greatly vary among individuals. Angioedema-particularly in the absence of hives-may also be caused by hereditary angioedema conditions resulting from aberrant regulation of contact system activation and excessive bradykinin generation or impairment of vascular integrity. In these patients, swelling can affect unpredictable locations and fail to respond to MC-directed therapies. Genetic variants have helped delineate key pathways in the etiology of urticaria and nonatopic angioedema and led to the development of targeted therapies. Herein, we describe the currently known inherited and acquired genetic causes for these conditions, highlight specific features in their clinical presentations, and discuss the benefits and limitations of biomarkers that can help distinguish them.

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.

Platelet-Adherent Leukocytes Associated With Cutaneous Cross-Reactive Hypersensitivity to Nonsteroidal Anti-Inflammatory Drugs

Nonsteroidal anti-inflammatory drugs (NSAIDs) are among the most highly consumed drugs worldwide and the main triggers of drug hypersensitivity reactions. The most frequent reaction, named cross-reactive NSAID-hypersensitivity, is due to the pharmacological activity of these drugs by blocking the cyclooxygenase-1 enzyme. Such inhibition leads to cysteinyl-leukotriene synthesis, mainly LTE4, which are responsible for the reaction. Although the complete molecular picture of the underlying mechanisms remains elusive, the participation of platelet-adherent leukocytes (CD61⁺) and integrins have been described for NSAID-exacerbated respiratory disease (NERD). However, there is a lack of information concerning NSAID-induced urticaria/angioedema (NIUA), by far the most frequent clinical phenotype. Here we have evaluated the potential role of CD61⁺ leukocytes and integrins (CD18, CD11a, CD11b, and CD11c) in patients with NIUA, and included the other two phenotypes with cutaneous involvement, NSAID-exacerbated cutaneous disease (NECD) and blended reactions (simultaneous skin and airways involvement). A group NSAID-tolerant individuals was also included. During the acute phase of the reaction, the three clinical phenotypes showed increased frequencies of CD61⁺ neutrophils, eosinophils, and monocytes compared to controls, which correlated with urinary LTE4 levels. However, no correlation was found between these variables at basal state. Furthermore, increased expressions of CD18 and CD11a were found in the three CD61⁺ leukocytes subsets in NIUA, NECD and blended reactions during the acute phase when compared with CD61^-leukocyte subpopulations. During the acute phase, CD61⁺ neutrophils, eosinophils and monocytes showed increased CD18 and CD11a expression when compared with CD61⁺ leukocytes at basal state. No differences were found when comparing controls and CD61⁺ leukocytes at basal state. Our results support the participation of platelet-adherent leukocytes and integrins in cutaneous cross-hypersensitivity to NSAIDs and provide a link between these cells and arachidonic acid metabolism. Our findings also suggest that these reactions do not involve a systemic imbalance in the frequency of CD61⁺ cells/integrin expression or levels of LTE4, which represents a substantial difference to NERD. Although further studies are needed, our results shed light on the molecular basis of cutaneous cross-reactive NSAID-hypersensitivity, providing potential targets for therapy through the inhibition of platelet-leukocyte interactions.

Pathogenesis of NSAID-induced reactions in aspirin-exacerbated respiratory disease

It is well-established that following ingestion of aspirin or any other inhibitor of cyclooxygenase-1, patients with Samter's disease, or aspirin-exacerbated respiratory disease (AERD) develop the sudden onset of worsening respiratory clinical symptoms, which usually involves nasal congestion, rhinorrhea, wheezing and bronchospasm. Gastrointestinal distress, nausea, a pruritic rash and angioedema can also occasionally develop. However, the underlying pathologic mechanism that drives these clinical reactions remains elusive. Pretreatment with medications that inhibit the leukotriene pathway decreases the severity of clinical reactions, which points to the involvement of cysteinyl leukotrienes (cysLTs) in the pathogenesis of these aspirin-induced reactions. Furthermore, studies of aspirin challenges in carefully-phenotyped patients with AERD have confirmed that both proinflammatory lipid mediators, predominantly cysLTs and prostaglandin (PG) D₂, and the influx of effector cells to the respiratory tissue, contribute to symptom development during aspirin-induced reactions. Mast cells, which have been identified as the major cellular source of cysLTs and PGD₂, are likely to be major participants in the acute reactions, and are an attractive target for future pharmacotherapies in AERD. Although several recent studies support the role of platelets as inflammatory effector cells and as a source of cysLT overproduction in AERD, it is not yet clear whether platelet activation plays a direct role in the development of the aspirin-induced reactions. To further our understanding of the pathogenesis of aspirin-induced reactions in AERD, and to broaden the pharmacotherapeutic options available to these patients, additional investigations with targeted clinical trials will be required.

Extrabronchial symptoms and late phase reaction enhance the diagnostic value of aspirin bronchial challenge

INTRODUCTION

Lysine aspirin (l-ASA) bronchial challenge can be used in the diagnostics of aspirin exacerbated respiratory disease. It is safer than oral challenge, however it is characterized by a lower sensitivity.

AIM

We sought to investigate whether additional indicators of the positive result of l-ASA bronchial challenge, i.e. late phase reaction (LPR) and extrabronchial symptoms (EBS), may enhance its diagnostic value.

MATERIAL AND METHODS

Sixty-seven patients with a positive history of asthma exacerbated by aspirin and/or other non-steroidal inflammatory drugs underwent l-ASA bronchial challenge. The control groups comprised 15 aspirin tolerant asthmatics and 15 healthy subjects. Forced expiratory volume in 1 s (FEV1) and 24-hour peak expiratory flow (PEF) measurements were performed in all subjects in order to recognize early and late response to l-ASA. All subjects underwent oral ASA challenge 2 weeks after l-ASA bronchial challenge.

RESULTS

Basing on FEV1 and PEF results, early reaction was present in 50.7% of patients, early and LPR in 29.9% and LPR in only 10.4% of aspirin exacerbated respiratory disease patients. The EBS were noted in 31.3% of subjects. Inclusion of LPR and EBS as positive criteria of the challenge increased sensitivity to 94.0%.

CONCLUSIONS

These results indicate that both LPR and EBS should be considered as positive criteria of aspirin bronchial challenge as they enhance its diagnostic value.

NSAID-exacerbated respiratory disease: a meta-analysis evaluating prevalence, mean provocative dose of aspirin and increased asthma morbidity

BACKGROUND

The prevalence and mean provocative dose of oral aspirin (MPDA) triggering respiratory reactions in people with asthma have been inconsistently reported, and the relationship between NSAID-exacerbated respiratory disease (NERD) and asthma morbidity was less well quantified.

METHODS

A systematic review was performed by identifying studies diagnosing NERD using blinded, placebo-controlled oral provocation challenge tests (OPCTs) or by self-reported history in people with asthma. Data were extracted, and effect estimates for changes in respiratory function, MPDA and asthma morbidity were pooled using random-effects meta-analysis.

RESULTS

The prevalence of NERD in adults with asthma was 9.0% (95% CI 6-12%) using OPCTs and 9.9% (95% CI 9.4-10.5%) using self-reported history from questionnaires. The MPDA in adults with NERD was 85.8 mg (95% CI 73.9-97.6). In people with NERD, the risk of: uncontrolled asthma was increased twofold (RR 1.96 (95% CI 1.25-3.07)); severe asthma and asthma attacks was increased by 60% (RR 1.58 (95% CI 1.15-2.16) and RR 1.59 (95% CI 1.21-2.09), respectively); emergency room visits was increased by 80% (RR 1.79 (95% CI 1.29-2.49)); and asthma hospitalization was increased by 40% (RR 1.37 (95% CI 1.12-1.67)) compared to people with NSAID-tolerant asthma.

CONCLUSIONS

Respiratory reactions triggered by oral aspirin in people with asthma are relatively common. At the population level, the prevalence of NERD was similar when measured using appropriately conducted OPCTs or by self-reported history. On average, respiratory reactions were triggered by clinically relevant doses of oral aspirin. Asthma morbidity was significantly increased in people with NERD who potentially require more intensive monitoring and follow-up.

The role of leukotrienes in allergic diseases

Leukotrienes (LTs), both LTB4 and the cysteinyl LTs (CysLTs) LTC4, LTD4 and LTE4, are implicated in a wide variety of inflammatory disorders. These lipid mediators are generated from arachidonic acid via multistep enzymatic reactions through which arachidonic acid is liberated from membrane phospholipids through the action of phospholipase A2. LTB4 and CysLTs exert their biological effects by binding to cognate receptors, which belong to the G protein-coupled receptor superfamily. LTB4 is widely considered to be a potent chemoattractant for most subsets of leukocytes, whereas CysLTs are potent bronchoconstrictors that have effects on airway remodeling. LTs play a central role in the pathogenesis of asthma and many other inflammatory diseases. This review will provide an update on the synthesis, biological function, and relevance of LTs to the pathobiology of allergic diseases, and examine the current and future therapeutic prospects of LT modifiers.

Aspirin desensitization in patients with aspirin-induced and aspirin-tolerant asthma: a double-blind study

BACKGROUND

Numerous open trials have demonstrated the beneficial clinical effects of aspirin desensitization (AD) in patients with aspirin-induced asthma (AIA). These beneficial effects might be attributable to aspirin's potent anti-inflammatory properties, but that supposition requires further corroboration.

OBJECTIVE

We sought to compare the clinical and biochemical responses to chronic oral AD in 20 patients with AIA and 14 patients with aspirin-tolerant asthma (ATA). All of the patients had chronic rhinosinusitis and nasal polyposis, and these responses were investigated in a pilot, double-blind, placebo-controlled study.

METHODS

Twelve patients with AIA and 6 patients with ATA were randomly assigned to receive 624 mg of aspirin, and 8 patients with AIA and 8 patients with ATA received placebo. Both aspirin and placebo were administered once daily for 6 months. Nasal symptoms, Sino-Nasal Outcome Test (SNOT20) scores, peak nasal inspiratory flows, Asthma Control Questionnaire scores, spirometric parameters, peak expiratory flows, blood eosinophilia, and corticosteroid doses were assessed on a monthly basis. Levels of urinary leukotriene E4 and the stable plasma prostaglandin (PG) D2 metabolite 9α,11β-PGF2 were evaluated at baseline and after 1, 3, 5, and 6 months.

RESULTS

Only the patients with AIA subjected to AD reported improvements in smell and reductions in sneezing and nasal blockade. The SNOT20 and Asthma Control Questionnaire scores of these patients decreased, and their peak nasal inspiratory flows increased. The dosages of inhaled corticosteroids were reduced. There were no changes in leukotriene E(4) or 9α,11β-PGF(2) levels after AD.

CONCLUSION

The clinically beneficial effects of AD on nasal and bronchial symptoms occurred only in the patients with AIA.

Aspirin-intolerant asthma: a comprehensive review of biomarkers and pathophysiology

Aspirin-exacerbated respiratory disease is a tetrad of nasal polyps, chronic hypertrophic eosinophilic sinusitis, asthma, and sensitivity to aspirin. Unawareness of this clinical condition by patients and physicians may have grave consequences because of its association with near-fatal asthma. The pathogenesis of aspirin-intolerant asthma is not related with an immunoglobin E mechanism, but with an abnormal metabolism of the lipoxygenase (LO) and cyclooxygenase (COX) pathways. At present, a diagnosis of aspirin sensitivity can be established only by provocative aspirin challenge, which represents a health risk for the patient. This circumstance has encouraged the search for aspirin intolerance-specific biomarkers. Major attempts have focused on mediators related with inflammation and eicosanoid regulation. The use of modern laboratory techniques including high-throughput methods has facilitated the detection of dozens of biological metabolites associated with aspirin-intolerant asthma disease. Not surprisingly, the majority of these is implicated in the LO and COX pathways. However, substantial amounts of data reveal the participation of many genes deriving from different ontologies. Biomarkers may represent a powerful, noninvasive tool in the diagnosis of aspirin sensitivity; moreover, they could provide a new way to classify asthma phenotypes.

Variants of CEP68 gene are associated with acute urticaria/angioedema induced by multiple non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are the most consumed drugs worldwide because of their efficacy and utility in the treatment of pain and inflammatory diseases. However, they are also responsible for an important number of adverse effects including hypersensitivity reactions. The most important group of these reactions is triggered by non-immunological, pharmacological mechanisms catalogued under the denomination of cross-intolerance (CRI), with acute urticaria/angioedema induced by multiple NSAIDs (MNSAID-UA) the most frequently associated clinical entity. A recent genome-wide association study identified the gene encoding the centrosomal protein of 68 KDa (CEP68) as the major locus associated with aspirin intolerance susceptibility in asthmatics. In this study, we aimed to assess the role of this locus in susceptibility to CRI to NSAIDs by examining 53 common gene variants in a total of 635 patients that were classified as MNSAID-UA (n = 399), airway exacerbations (n = 110) or blended pattern (n = 126), and 425 controls. We found in the MNSAID-UA group a number of variants (17) associated (lowest p-value = 1.13×10⁻⁶), including the non-synonymous Gly74Ser variant (rs7572857) previously associated with aspirin intolerance susceptibility in asthmatics. Although not being significant in the context of multiple testing, eight of these variants were also associated with exacerbated respiratory disease or blended reactions. Our results suggest that CEP68 gene variants may play an important role in MNSAID-UA susceptibility and, despite the different regulatory mechanisms involved depending on the specific affected organ, in the development of hypersensitivity reactions to NSAIDs.

Genome-wide association study in NSAID-induced acute urticaria/angioedema in Spanish and Han Chinese populations

AIM

Acute urticaria/angioedema (AUA) induced by cross-intolerance to NSAIDs is the most frequent clinical entity in hypersensitivity reactions to drugs. In this work, we conducted a genome-wide association study in Spanish and Han Chinese patients suffering from NSAID-induced AUA.

MATERIALS & METHODS

A whole-genome scan was performed on a total of 232 cases (112 Spanish and 120 Han Chinese) with NSAID-induced AUA and 225 unrelated controls (124 Spanish and 101 Han Chinese).

RESULTS

Although no polymorphism reached genome-wide significance, we obtained suggestive associations for three clusters in the Spanish group (RIMS1, BICC1 and RAD51L 1) and one region in the Han Chinese population (ABI3BP). Five regions showed suggestive associations after meta-analysis: HLF, RAD51L1, COL24A1, GalNAc-T13 and FBXL7. A majority of these genes are related to Ca(2+), cAMP and/or P53 signaling pathways.

CONCLUSION

The associations described were different from those related to the metabolism of arachidonic acid and could provide new mechanisms underlying NSAID-induced AUA.

Role of imbalance of eicosanoid pathways and staphylococcal superantigens in chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a multifactorial disease of the upper airways with a high prevalence (approximately 11%) in the general population. Different immune and inflammatory mechanisms are involved in its pathogenesis. Alterations in the arachidonic acid pathway (leading to an imbalanced production of eicosanoids) have been linked to the pathophysiology of different diseases especially nasal polyposis, asthma, and aspirin-exacerbated respiratory disease. Furthermore, viral and bacterial infections have been identified as important factors amplifying the pro-inflammatory reactions in these pathologies. This review summarizes the impact of an imbalance in the eicosanoid pathway and the effect of Staphylococcus aureus enterotoxins on the regulation of the pro-inflammatory network in CRS and their translation into disease severity.

The values of nasal provocation test and basophil activation test in the different patterns of ASA/NSAID hypersensitivity

BACKGROUND

The oral provocation test (OPT) is the current gold standard to diagnose aspirin hypersensitivity syndrome although it is time-consuming and contains some systemic risks. Other reliable methods with lower side effects and shorter test duration are being investigated.

OBJECTIVE

The purpose of this study was to evaluate the efficacy of the nasal provocation test (NPT) and the basophil activation test (BAT) in the diagnosis of different subtypes of aspirin sensitivity.

METHODS

Thirty aspirin sensitivity patients with cutaneous and respiratory manifestations underwent NPT and BAT with lysine-ASA. NPT result was interpreted as recommended in EAACI/GA2LEN guidelines and receiver operating characteristic analysis of BAT was performed by using 15 NSAIDs tolerant volunteers as a control group.

RESULTS

NPT was positive in 60% (18/30) of patients and BAT was positive in 76.7% (23/30) of patients. The incubation of basophils with 0.31 mg/ml of lysine-aspirin and using 4.6% activated basophils gives the best predictive values to diagnose aspirin sensitivity. The combination of both tests yielded positive results in 80% and 93.3% of aspirin-induced cutaneous and respiratory patterns. The agreement between NPT and BAT results was 63.3%.

CONCLUSIONS

NPT and BAT are beneficial to detect patients with aspirin sensitivity. The combination of both tests have additional diagnostic values; less time-consuming than OPT and their complications are negligible. A reliable alternative method with minimum side effects is needed to diagnose aspirin sensitivity in suspected patients who have contraindications for OPT.

Urinary leukotrienes in patients with nasal polyposis

Objectives

To compare urinary leukotriene E4 (ULT) level in patients with nasal polyposis (NP) with and without aspirin intolerance and allergic rhinitis (AR), and correlate it with disease severity.

Study Design and Setting

Prospective study from November 2005 to November 2006. Patients with NP (n = 30) and AR (n = 35) were included. The concentration of ULT was measured in both groups. Oral provocation test with aspirin was performed to patients with NP. ULT level between both groups was compared and correlated with NP disease severity.

Results

ULT concentration was elevated on NP and AR. The patients with NP and aspirin intolerance (n = 4) presented higher levels of ULT compared to aspirin-tolerant patients. Leukotriene concentration was not correlated with NP severity.

Conclusions

Patients with NP and aspirin intolerance have increased ULT excretion; thus their measurement can be used as an indicator of arachidonic acid metabolism alteration.

Systemic responses after bronchial aspirin challenge in sensitive patients with asthma

BACKGROUND

In aspirin-sensitive patients with asthma, bronchial obstruction induced by oral aspirin may be associated with extrabronchial symptoms, suggesting the systemic character of the response.

OBJECTIVE

Go assess potential systemic effects of local aspirin challenge, hemopoietic progenitors were measured in the peripheral blood of challenged patients.

METHODS

In 19 patients with a history of aspirin-induced asthma, placebo-controlled bronchial challenges with lysine-aspirin were performed. Peripheral blood was collected before and then 1 hour and 20 hours after challenge (placebo or aspirin). Using the flow-cytometric method, the numbers of leukocyte (CD34+ cells) and eosinophil (CD34+CD125+ cells) progenitors were determined.

RESULTS

The challenge was positive in 13 patients; 6 patients had isolated local bronchial reaction, and 7 patients developed systemic symptoms (bronchial and extrabronchial). In patients with positive challenge (n = 13), leukocyte progenitors increased significantly at 1 hour and 20 hours after challenge (mean, 0.04% at baseline, 0.066% at 1 hour after challenge, and 0.073% at 20 hours; P < .05). Eosinophil progenitors raised significantly from mean 0.017% before challenge to 0.04% (P < .05) at 20 hours after the challenge. At 20 hours after the challenge, the increase in leukocyte and eosinophil progenitors was observed only in patients with systemic reactions. Positive aspirin challenge was associated with a significant increase in eotaxin 2 serum concentration.

CONCLUSION

This study demonstrated that bronchial challenge with aspirin may involve systemic reactions and is associated with mobilization of leukocyte and eosinophil progenitor cells from the bone marrow.

Cysteinyl-leukotrienes and their receptors in asthma and other inflammatory diseases: critical update and emerging trends

Cysteinyl-leukotrienes (cysteinyl-LTs), that is, LTC4, LTD4, and LTE4, trigger contractile and inflammatory responses through the specific interaction with G protein-coupled receptors (GPCRs) belonging to the purine receptor cluster of the rhodopsin family, and identified as CysLT receptors (CysLTRs). Cysteinyl-LTs have a clear role in pathophysiological conditions such as asthma and allergic rhinitis (AR), and have been implicated in other inflammatory conditions including cardiovascular diseases, cancer, atopic dermatitis, and urticaria. Molecular cloning of human CysLT1R and CysLT2R subtypes has confirmed most of the previous pharmacological characterization and identified distinct expression patterns only partially overlapping. Interestingly, recent data provide evidence for the immunomodulation of CysLTR expression, the existence of additional receptor subtypes, and of an intracellular pool of CysLTRs that may have roles different from those of plasma membrane receptors. Furthermore, genetic variants have been identified for the CysLTRs that may interact to confer risk for atopy. Finally, a crosstalk between the cysteinyl-LT and the purine systems is being delineated. This review will summarize and attempt to integrate recent data derived from studies on the molecular pharmacology and pharmacogenetics of CysLTRs, and will consider the therapeutic opportunities arising from the new roles suggested for cysteinyl-LTs and their receptors.

Aspirin-sensitive rhinosinusitis is associated with reduced E-prostanoid 2 receptor expression on nasal mucosal inflammatory cells

BACKGROUND

Impaired braking of inflammatory cell cysteinyl leukotriene production by prostaglandin (PG) E(2) has been implicated in the pathogenesis of aspirin exacerbated airways disease, but the mechanism is obscure. PGE(2) acts via G-protein-coupled receptors, E-prostanoid (EP)(1-4,) but there is little information on the expression of PGE(2) receptors in this condition.

OBJECTIVE

To address the hypothesis that expression of 1 or more EP receptors on nasal mucosal inflammatory cells is deficient in patients with aspirin-sensitive compared with nonaspirin-sensitive polypoid rhinosinusitis.

METHODS

By using specific antibodies, immunohistochemistry, and image analysis, we measured the expression of EP(1-4) in nasal biopsies from patients with aspirin-sensitive (n = 12) and nonaspirin-sensitive (n = 10) polypoid rhinosinusitis and normal controls (n = 9). Double-staining was used to phenotype inflammatory leukocytes expressing EP(1-4).

RESULTS

Global mucosal expression of EP(1) and EP(2), but not EP(3) or EP(4), immunoreactivity was significantly elevated in aspirin-sensitive and nonaspirin-sensitive rhinosinusitis compared with controls (P < .03). This was attributable principally to elevated expression on tubulin(+) epithelial cells and Mucin 5 subtypes A and B (Muc-5AC(+)) goblet cells. In contrast, the percentages of neutrophils, mast cells, eosinophils, and T cells expressing EP(2), but not EP(1), EP(3), or EP(4), were significantly reduced (P < or = .04) in the aspirin-sensitive compared with nonaspirin-sensitive patients.

CONCLUSION

The data suggest a possible role for PGE(2) in mediating epithelial repair in rhinitis and asthma. Because PGE(2) exerts a range of inhibitory actions on inflammatory leukocytes via the EP(2) receptor, its reduced expression in aspirin-sensitive rhinosinusitis may be partly responsible for the increased inflammatory infiltrate and production of cysteinyl leukotrienes that characterize aspirin-sensitive disease.

Nutrigenomics and nutrigenetics: the emerging faces of nutrition

The recognition that nutrients have the ability to interact and modulate molecular mechanisms underlying an organism's physiological functions has prompted a revolution in the field of nutrition. Performing population-scaled epidemiological studies in the absence of genetic knowledge may result in erroneous scientific conclusions and misinformed nutritional recommendations. To circumvent such issues and more comprehensively probe the relationship between genes and diet, the field of nutrition has begun to capitalize on both the technologies and supporting analytical software brought forth in the post-genomic era. The creation of nutrigenomics and nutrigenetics, two fields with distinct approaches to elucidate the interaction between diet and genes but with a common ultimate goal to optimize health through the personalization of diet, provide powerful approaches to unravel the complex relationship between nutritional molecules, genetic polymorphisms, and the biological system as a whole. Reluctance to embrace these new fields exists primarily due to the fear that producing overwhelming quantities of biological data within the confines of a single study will submerge the original query; however, the current review aims to position nutrigenomics and nutrigenetics as the emerging faces of nutrition that, when considered with more classical approaches, will provide the necessary stepping stones to achieve the ambitious goal of optimizing an individual's health via nutritional intervention.

The broken balance in aspirin hypersensitivity

Aspirin was introduced into medicine over a century ago and has become the most popular drug in the world. Although the first hypersensitivity reaction was described soon after aspirin had been marketed, only recently a phenomenon of cysteinyl leukotriene overproduction brought new insights on a balance between pro- and anti-inflammatory mediators derived from arachidonic acid. We describe the most common clinical presentations of aspirin hypersensitivity, i.e. aspirin-induced asthma, rhinosinusitis and aspirin-induced urticaria. We also present their biochemical background. Despite relatively high incidence of these reactions, aspirin hypersensitivity remains underdiagnosed worldwide. Acute reactions of aspirin hypersensitivity are elicited via cyclooxygenase inhibition by non-steroid anti-inflammatory drugs. Coxibs, selective inhibitors of cyclooxygenase-2 isoenzyme, do not precipitate symptoms in susceptible patients. Though hypersensitivity correlates with cyclooxygenase-1 inhibition, diminished tissue expression was described only for cyclooxygenase-2. Aspirin-induced asthma and aspirin-induced urticaria, in a substantial part of the patients, are driven by a release of mediators from activated mast cells. These cells in physiological conditions are under inhibitory control of prostaglandin E2. The origin of aspirin hypersensitivity remains unknown, but accumulating data from genetic studies strongly suggest that environmental factor, possibly a common viral infection, can trigger the disease in susceptible subjects.

Expression of the cysteinyl leukotriene receptors cysLT(1) and cysLT(2) in aspirin-sensitive and aspirin-tolerant chronic rhinosinusitis

BACKGROUND

Cysteinyl leukotrienes play a disease-regulating role in rhinosinusitis and asthma, particularly aspirin-sensitive disease. They act through 2 G-protein coupled receptors termed cysteinyl leukotriene type 1 receptor (cysLT 1 ) and cysteinyl leukotriene type 2 receptor (cysLT 2 ). We previously compared expression of cysLT 1 on mucosal leukocytes in patients with aspirin-sensitive and aspirin-tolerant rhinosinusitis.

OBJECTIVE

To compare expression of cysLT 1 and cysLT 2 on leukocytes, mucus glands, and epithelium in 32 patients with chronic polypoid rhinosinusitis (21 aspirin-sensitive, 11 aspirin-tolerant) and 9 normal controls.

METHODS

Total numbers of CD45 + leukocytes, percentages of these cells expressing cysLT 1 or cysLT 2 , and percentages of the total epithelial and glandular areas expressing cysLT 1 or cysLT 2 were measured in sections of nasal biopsies by using immunohistochemistry and image analysis.

RESULTS

The percentages of mucosal CD45 + leukocytes expressing cysLT 1 were significantly ( P < .0001) elevated in the aspirin-sensitive but not the aspirin-tolerant patients compared with the controls. In contrast, the percentages of leukocytes expressing cysLT 2 did not differ significantly in the 3 groups. On epithelial and glandular cells, expression of cysLT 2 significantly exceeded that of cysLT 1 in both the patients with rhinosinusitis and the controls ( P < or = .004), although there was no significant difference in the expression of either receptor in the patients with rhinosinusitis (aspirin-sensitive or aspirin-tolerant) and the controls.

CONCLUSION

Although cysLT 1 expression predominates on inflammatory leukocytes in patients with aspirin-sensitive rhinosinusitis, the effects of cysteinyl leukotrienes on glands and epithelium may be mediated predominantly through cysLT 2. This has potentially important therapeutic implications.