Mediator production and severity of aspirin-induced respiratory reactions: Impact of sampling site and body mass index.

BACKGROUND: Patients with aspirin-exacerbated respiratory disease can experience severe reactions during aspirin challenge that are associated with high levels of mast cell mediators. The tissue source and clinical factors contributing to systemic mediator levels are unknown. OBJECTIVE: We sought to determine the concordance between respiratory tract and systemic inflammatory mediator levels and identify clinical factors associated with these mediators. METHODS: We performed an oral aspirin challenge in 30 subjects with aspirin-exacerbated respiratory disease. Respiratory symptoms and function, nasal mucosal fluid, blood, and urine were collected at baseline, at the onset of a respiratory reaction, and over a 3-hour observation period. Changes in nasal and systemic mediator levels were compared. RESULTS: Neither tryptase nor leukotriene E4 levels in nasal fluid correlated with serum tryptase or urinary leukotriene E4 levels at baseline or during reactions. We observed no association between the baseline or aspirin-induced change in nasal versus urinary leukotriene E4 and serum tryptase levels. Body mass index inversely correlated with baseline and aspirin-induced urinary leukotriene E4, prostaglandin D2 metabolite, and serum tryptase levels, as well as with aspirin-induced symptoms and respiratory function, but not with nasal mediators. CONCLUSIONS: The levels of nasal and systemic aspirin-induced mast cell products are discordant in aspirin-exacerbated respiratory disease. Systemically detected levels are likely derived from mast cells outside of the sinonasal cavity and do not accurately reflect upper respiratory tract production. Increased body mass index decreases systemic mast cell mediator production and reaction severity, supporting a contribution of metabolic regulation in aspirin-induced systemic reactions.

Urine Leukotriene E4: Implications as a Biomarker in Chronic Rhinosinusitis.

OBJECTIVE: To provide a comprehensive state-of-the-art review of the emerging role of urine leukotriene E4 (uLTE4) as a biomarker in the diagnosis of chronic rhinosinusitis (CRS), aspirin-exacerbated respiratory disease (AERD), and asthma. DATA SOURCES: Ovid MEDLINE(R), Ovid EMBASE, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, and Scopus. REVIEW METHODS: A state-of-the-art review was performed investigating the role of uLTE4 as a diagnostic biomarker, predictor of disease severity, and potential marker of selected therapeutic efficacy. CONCLUSIONS: uLTE4 has been shown to be a reliable and clinically relevant biomarker for CRS, AERD, and asthma. uLTE4 is helpful in ongoing efforts to better endotype patients with CRS and to predict disease severity. IMPLICATIONS FOR PRACTICE: Aside from being a diagnostic biomarker, uLTE4 is also able to differentiate aspirin-tolerant patients from patients with AERD and has been associated with objective disease severity in patients with CRS with nasal polyposis. uLTE4 levels have also been shown to predict response to medical therapy, particularly leukotriene-modifying agents.

Mepolizumab targets multiple immune cells in aspirin-exacerbated respiratory disease.

BACKGROUND: Eosinophilic asthma and nasal polyposis are hallmarks of aspirin-exacerbated respiratory disease (AERD), and IL-5 inhibition has been shown to provide therapeutic benefit. However, IL-5Rα is expressed on many cells in addition to eosinophils, and the mechanisms by which IL-5 inhibition leads to clinical benefit in eosinophilic asthma and nasal polyposis are unlikely to be due exclusively to antieosinophil effects. OBJECTIVE: We sought to identify the mechanisms by which anti-IL-5 treatment with mepolizumab improves respiratory inflammation in AERD. METHODS: The clinical characteristics, circulating granulocytes, nasal scraping transcripts, eosinophilic cationic protein, tryptase, and antibody levels, and urinary and nasal eicosanoid levels were measured for 18 subjects with AERD who were taking mepolizumab and compared with those of 18 matched subjects with AERD who were not taking mepolizumab. RESULTS: Subjects taking mepolizumab had significantly fewer peripheral blood eosinophils and basophils, and those cells that remained had higher surface CRTH2 expression than did the cells from subjects not taking mepolizumab. Nasal prostaglandin F2α, prostaglandin D2 metabolites, leukotriene B4, and thromboxane levels were lower in subjects taking mepolizumab, as were urinary levels of tetranor-prostaglandin D2 and leukotriene E4. The nasal epithelial cell transcripts that were overexpressed among subjects with AERD who were taking mepolizumab were enriched for genes involved in tight junction formation and cilium organization. Nasal and urinary prostaglandin E2, tryptase, and antibody levels were not different between the 2 groups. CONCLUSION: IL-5 inhibition in AERD decreases production of inflammatory eicosanoids and upregulates tight junction-associated nasal epithelial cell transcripts, likely due to decreased IL-5 signaling on tissue mast cells, eosinophils, and epithelial cells. These direct effects on multiple relevant immune cells contribute to the mechanism of benefit afforded by mepolizumab.

Omalizumab for Aspirin Hypersensitivity and Leukotriene Overproduction in Aspirin-exacerbated Respiratory Disease. A Randomized Controlled Trial.

Rationale: Aspirin-exacerbated respiratory disease is characterized by severe asthma, nonsteroidal antiinflammatory drug hypersensitivity, nasal polyposis, and leukotriene overproduction. Systemic corticosteroid therapy does not completely suppress lifelong aspirin hypersensitivity. Omalizumab efficacy against aspirin-exacerbated respiratory disease has not been investigated in a randomized manner.Objectives: To evaluate omalizumab efficacy against aspirin hypersensitivity, leukotriene E4 overproduction, and symptoms during an oral aspirin challenge in patients with aspirin-exacerbated respiratory disease using a randomized design.Methods: We performed a double-blind, randomized, crossover, placebo-controlled, single-center study at Sagamihara National Hospital between August 2015 and December 2016. Atopic patients (20-79 yr old) with aspirin-exacerbated respiratory disease diagnosed by systemic aspirin challenge were randomized (1:1) to a 3-month treatment with omalizumab or placebo, followed by a >18-week washout period (crossover design). The primary endpoint was the difference in area under logarithm level of urinary leukotriene E4 concentration versus time curve in the intent-to-treat population during an oral aspirin challenge.Measurements and Main Results: Sixteen patients completed the study and were included in the analysis. The area under the logarithm level of urinary leukotriene E4 concentration versus time curve during an oral aspirin challenge was significantly lower in the omalizumab phase (median [interquartile range], 51.1 [44.5-59.8]) than in the placebo phase (80.8 [interquartile range, 65.4-87.8]) (P < 0.001). Ten of 16 patients (62.5%) developed oral aspirin tolerance up to cumulative doses of 930 mg in the omalizumab phase (P < 0.001).Conclusions: Omalizumab treatment inhibited urinary leukotriene E4 overproduction and upper/lower respiratory tract symptoms during an oral aspirin challenge, resulting in aspirin tolerance in 62.5% of the patients with aspirin-exacerbated respiratory disease.

Prostaglandin E2 decrease in induced sputum of hypersensitive asthmatics during oral challenge with aspirin.

BACKGROUND: A special regulatory role for prostaglandin E2 (PGE2 ) has been postulated in nonsteroidal anti-inflammatory drug (NSAID)-exacerbated respiratory disease (NERD). OBJECTIVE: To investigate the effect of systemic aspirin (acetylsalicylic acid) administration on airway PGE2 biosynthesis in induced sputum supernatant (ISS) among subjects with NERD or aspirin-tolerant asthma with chronic rhinosinusitis with nasal polyposis (ATA-CRSwNP), as well as healthy controls (HC). METHODS: Induced sputum (IS) was collected from patients with NERD (n = 26), ATA-CRSwNP (n = 17), and HC (n = 21) at baseline and after aspirin challenge. Sputum differential cell count and IS supernatant (ISS) levels of prostanoids, PGE2 , 8-iso-PGE2 , tetranor-PGE-M, 8-iso-PGF2 α, and leukotriene C4 , D4 , and E4 , were determined using mass spectrometry. Urinary excretion of LTE4 was measured by ELISA. RESULTS: NERD subjects had elevated sputum eosinophilic count as compared to ATA-CRSwNP and HC (median NERD 9.1%, ATA-CRSwNP 2.1%, and HC 0.4%; P < 0.01). Baseline ISS levels of PGE2 were higher in asthmatics as compared to HC at baseline (NERD vs HC P = 0.04, ATA-CRSwNP vs HC P < 0.05). Post-challenge ISS levels of PGE2 compared to baseline significantly decreased in NERD and HC (P < 0.01 and P = 0.01), but not in ATA-CRSwNP. In NERD, a similar decrease in PGE2 as in HC resulted from 2.8 times lower dose of aspirin. CONCLUSION: Aspirin-precipitated bronchoconstriction is associated with a decrease in airway PGE2 biosynthesis. These results support the mechanism of PGE2 biosynthesis inhibition as a trigger for bronchoconstriction in NERD.

Sinus Surgery Is Associated with a Decrease in Aspirin-Induced Reaction Severity in Patients with Aspirin Exacerbated Respiratory Disease.

BACKGROUND: Nasal polyps influence the burden of aspirin-exacerbated respiratory disease (AERD) by contributing to eicosanoid production. AERD is diagnosed through graded aspirin challenges. It is not known how sinus surgery affects aspirin challenge outcomes. OBJECTIVE: To investigate the effects of endoscopic sinus surgery (ESS) on aspirin-induced reaction severity and on the levels of eicosanoids associated with these reactions. METHODS: Twenty-eight patients with AERD were challenged with aspirin before and 3 to 4 weeks after ESS. Respiratory parameters and plasma and urine levels of eicosanoids were compared before and after challenges. RESULTS: Before ESS, AERD diagnosis was confirmed in all study patients by aspirin challenges that resulted in hypersensitivity reactions. After ESS, reactions to aspirin were less severe in all patients and 12 of 28 patients (43%, P < .001) had no detectable reaction. A lack of clinical reaction to aspirin was associated with lower peripheral blood eosinophilia (0.1 K/µL [interquartile range (IQR) 0.1-0.3] vs 0.4 K/µL [IQR 0.2-0.8]; P = .006), lower urinary leukotriene E4 levels after aspirin challenge (98 pg/mg creatinine [IQR 61-239] vs 459 pg/mg creatinine [IQR 141-1344]; P = .02), and lower plasma prostaglandin D2 to prostaglandin E2 ratio (0 [±0] vs 0.43 [±0.2]; P = .03), compared with those who reacted. CONCLUSIONS: Sinus surgery results in decreased aspirin sensitivity and a decrease in several plasma and urine eicosanoid levels in patients with AERD. Diagnostic aspirin challenges should be offered to patients with suspected AERD before ESS to increase diagnostic accuracy. Patients with established AERD could undergo aspirin desensitizations after ESS as the severity of their aspirin-induced hypersensitivity reactions lessens.

The utility of biomarkers in diagnosis of aspirin exacerbated respiratory disease.

BACKGROUND: Aspirin-exacerbated respiratory disease (AERD) is a distinct eosinophilic phenotype of severe asthma with accompanying chronic rhinosinusitis, nasal polyposis, and hypersensitivity to aspirin. Urinary 3-bromotyrosine (uBrTyr) is a noninvasive marker of eosinophil-catalyzed protein oxidation. The lack of in vitro diagnostic test makes the diagnosis of AERD difficult. We aimed to determine uBrTyr levels in patients with AERD (n = 240) and aspirin-tolerant asthma (ATA) (n = 226) and to assess whether its addition to urinary leukotriene E4 (uLTE4) levels and blood eosinophilia can improve the prediction of AERD diagnosis. METHODS: Clinical data, spirometry and blood eosinophilis were evaluated. UBrTyr and uLTE4 levels were measured in urine by HPLC and ELISA, respectively. RESULTS: Both groups of asthmatics (AERD, n = 240; ATA, n = 226) had significantly higher uBrTyr, uLTE4 levels, and blood eosinophils than healthy controls (HC) (n = 71) (p < 0.05). ULTE4 levels and blood eosinophils were significantly higher in AERD as compared to ATA (p = 0.004, p < 0.0001, respectively). whereas uBrTyr levels were not significantly different between both asthma phenotypes (p = 0.34). Asthmatics with high levels of uBrTyr (> 0.101 ng/mg Cr), uLTE4 levels (> 800 pg/mg Cr) and blood eosinophils (> 300 cells/ul) were 7 times more likely to have AERD.. However, uBrTyr did not increase the benefit for predicting AERD when uLTE4 and blood eosinophils were already taken into account (p = 0.57). CONCLUSION: UBrTyr levels are elevated both in AERD and ATA as compared to HC, but they could not differentiate between these asthma phenotypes suggesting a similar eosinophilic activation. The addition of uBrTyr to elevated uLTE4 levels and blood eosinophils did not statistically enhance the prediction of AERD diagnosis.

Omalizumab can inhibit respiratory reaction during aspirin desensitization.

BACKGROUND: Aspirin desensitization has been associated with benefit in management of aspirin-exacerbated respiratory disease (AERD). An intervention that would encourage aspirin desensitization to be performed more frequently has substantial potential for improving outcomes and quality of life in patients with AERD. OBJECTIVE: We investigated whether omalizumab administration would be associated with attenuation of aspirin-provoked bronchospasm in patients with AERD undergoing aspirin desensitization. METHODS: We carried out a randomized, double-blind, placebo-controlled study in which subjects with AERD who fulfilled label criteria for omalizumab received omalizumab or placebo for 16 weeks, and then underwent aspirin desensitization. RESULTS: Eleven subjects completed aspirin desensitization. Of the 7 who were randomized to omalizumab, 5 had no respiratory reaction during aspirin desensitization. Compared with placebo, omalizumab was associated with a significantly greater likelihood for subjects with AERD to have no respiratory reaction during desensitization (P = .04, Fisher exact test). There was an overall difference in urinary leukotriene E4 (LTE4) levels in subjects who received omalizumab and did not have a respiratory reaction during desensitization compared with subjects randomized to placebo (P = .035, mixed model with interaction). Urinary LTE4 levels were significantly higher with respiratory reaction in placebo subjects compared with levels obtained after the 100-mg dose in AERD subjects who had no respiratory reaction (P < .001, mixed model with interaction). CONCLUSION: In atopic AERD subjects, omalizumab administration for 16 weeks was associated with "clinically silent" desensitization. Further studies to investigate the therapeutic utility of omalizumab in patients with AERD who are candidates for aspirin desensitization are warranted based on these findings. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT00555971.

Dietary Fatty Acid Modification for the Treatment of Aspirin-Exacerbated Respiratory Disease: A Prospective Pilot Trial.

BACKGROUND: The high levels of eicosanoid production and the clinical efficacy of leukotriene-modifying pharmacotherapies for patients with aspirin-exacerbated respiratory disease (AERD) suggest that other interventions targeting arachidonic acid dysregulation may also improve disease control. OBJECTIVE: To assess the utility of a high omega-3/low omega-6 diet for the treatment of AERD. METHODS: Prospective, nonblinded dietary intervention in 10 adult patients with AERD at Brigham and Women's Hospital in Boston, MA. The primary objective was for subjects to reduce dietary omega-6 fatty acid consumption to less than 4 g/d and increase omega-3 intake to more than 3 g/d. The primary outcome was change in urinary leukotriene E4, with changes in other eicosanoids, platelet activation, lung function, and patient-reported questionnaires also assessed. RESULTS: Of the 10 subjects who screened for the study, all 10 completed the dietary intervention. Urinary leukotriene E4 decreased by 0.17 ng/mg (95% CI, -0.29 to -0.04; P = .02) and tetranor prostaglandin D-M decreased by 0.66 ng/mg creatinine (95% CI, -1.21 to -0.11; P = .02). There was a 15.1-point reduction in the 22-item Sino-Nasal Outcome Test score (95% CI, -24.3 to -6.0; P = .01), a 0.27-point reduction in the 7-item Asthma Control Questionnaire score (95% CI, -0.52 to -0.03; P = .03), and no change in FEV1 % predicted (P = .92) or forced vital capacity % predicted (P = .74). All patients lost some weight over the 2-week intervention period, and there were no diet-associated adverse events. CONCLUSIONS: A high omega-3/low omega-6 diet may be an appropriate adjunct treatment option for patients with AERD.

Group 2 innate lymphoid cells are recruited to the nasal mucosa in patients with aspirin-exacerbated respiratory disease.

BACKGROUND: Aspirin-exacerbated respiratory disease (AERD) is characterized by tissue eosinophilia and mast cell activation, including abundant production of prostaglandin D2 (PGD2). Group 2 innate lymphoid cells (ILC2s), which promote tissue eosinophilia and mast cell responses, undergo chemotaxis and cytokine production in response to PGD2, but it is unknown whether ILC2s are active in patients with AERD. OBJECTIVE: We sought to determine whether ILC2 numbers change in peripheral blood and the nasal mucosa during COX-1 inhibitor-induced reactions in patients with AERD. METHODS: Blood and nasal scrapings were collected at baseline, during reactions, and after completion of ketorolac/aspirin challenge/desensitization in 12 patients with AERD. ILC2s and eosinophils were quantitated by means of flow cytometry. Urine was also collected, and quantification of PGD2 metabolite and leukotriene E4 levels was done by using ELISA. Baseline and nonsteroidal anti-inflammatory drug reaction clinical data were correlated with cell changes. RESULTS: ILC2 numbers significantly increased in nasal mucosal samples and decreased in blood at the time of COX-1 inhibitor reactions in 12 patients with AERD. These changes were not observed in 2 patients without AERD. Furthermore, eosinophil numbers decreased in blood concurrently with significant increases in urinary PGD2 metabolite and leukotriene E4 levels. The magnitude of increases in nasal mucosal ILC2 numbers positively correlated with maximum symptom scores during challenges. Furthermore, blood ILC2 numbers during the reaction correlated with time for the reaction to resolve, possibly reflecting reaction severity. CONCLUSIONS: ILC2s are recruited to the nasal mucosa during COX-1 inhibitor-induced reactions in patients with AERD, correlating with enhanced production of prostaglandins and leukotrienes.

Exploration of the Sphingolipid Metabolite, Sphingosine-1-phosphate and Sphingosine, as Novel Biomarkers for Aspirin-exacerbated Respiratory Disease.

Sphingolipid (SL) metabolites have been suggested to be important inflammatory mediators in airway inflammation and asthma. However, little is known about SL metabolites in aspirin-exacerbated respiratory disease (AERD). We aimed to explore the potential AERD biomarkers by conducting lipidomics targeting SL metabolites. The levels of SL metabolites in serum and urine samples from 45 AERD patients and 45 aspirin-tolerant asthma (ATA) patients were quantified through mass spectrometry. During the lysine-aspirin bronchoprovocation test (ASA-BPT), the levels of serum sphingomyelin (SM) were significantly decreased in AERD (P < 0.05) but not in ATA. The serum SM levels were positively correlated with airway responsiveness to methacholine. At the basal status before the ASA-BPT, the levels of serum sphingosine-1-phosphate (S1P) and urine sphingosine were significantly higher in the AERD patients compared with that of ATA patients (P < 0.001) and were positively correlated with a greater decrease in FEV1 (%) values following the ASA-BPT test (P < 0.001 for each), and with serum periostin level (P < 0.05 for each). This study is the first to evaluate serum S1P and urine sphingosine as potential biomarkers of AERD as well as to examine the metabolic disturbance of SL in AERD patients.

Thymic stromal lymphopoietin controls prostaglandin D2 generation in patients with aspirin-exacerbated respiratory disease.

BACKGROUND: Prostaglandin (PG) D2 is the dominant COX product of mast cells and is an effector of aspirin-induced respiratory reactions in patients with aspirin-exacerbated respiratory disease (AERD). OBJECTIVE: We evaluated the role of the innate cytokine thymic stromal lymphopoietin (TSLP) acting on mast cells to generate PGD2 and facilitate tissue eosinophilia and nasal polyposis in patients with AERD. METHODS: Urinary eicosanoid levels were measured in aspirin-tolerant control subjects and patients with AERD. Nasal polyp specimens from patients with AERD and chronic rhinosinusitis were analyzed by using quantitative PCR, Western blotting, and immunohistochemistry. Human cord blood-and peripheral blood-derived mast cells were stimulated with TSLP in vitro to assess PGD2 generation. RESULTS: Urinary levels of a stable PGD2 metabolite (uPGD-M) were 2-fold higher in patients with AERD relative to those in control subjects and increased further during aspirin-induced reactions. Peak uPGD-M levels during aspirin reactions correlated with reductions in blood eosinophil counts and lung function and increases in nasal congestion. Mast cells sorted from nasal polyps expressed PGD2 synthase (hematopoietic PGD2 synthase) mRNA at higher levels than did eosinophils from the same tissue. Whole nasal polyp TSLP mRNA expression correlated strongly with mRNA encoding hematopoietic PGD2 synthase (r = .75), the mast cell-specific marker carboxypeptidase A3 (r = .74), and uPGD-M (r = 0.74). Levels of the cleaved active form of TSLP were increased in nasal polyps from patients with AERD relative to those in aspirin-tolerant control subjects. Recombinant TSLP induced PGD2 generation by cultured human mast cells. CONCLUSIONS: Our study demonstrates that mast cell-derived PGD2 is a major effector of type 2 immune responses driven by TSLP and suggests that dysregulation of this innate system contributes significantly to the pathophysiology of AERD.

Differences in urinary leukotriene E4 levels and distribution of eosinophils between chronic rhinosinusitis patients with aspirin-intolerant and -tolerant asthma.

OBJECTIVE: Urinary leukotriene E4 (U-LTE4) concentrations are significantly elevated in patients with aspirin-intolerant asthma (AIA). However, the relationship between the clinicopathogenetic features of eosinophilic rhinosinusitis and U-LTE4 concentration remains unknown. Here we examined the relationship between U-LTE4 level and eosinophil in chronic rhinosinusitis. METHODS: We measured the U-LTE4 concentrations and eosinophil counts in ethmoidal and maxillary sinuses and peripheral blood in 30 asthmatic patients (including 15 AIA patients). RESULTS: Eosinophil counts in ethmoidal sinuses and peripheral blood were markedly higher in asthmatic patients than in controls. Although there were no significant differences between eosinophil counts in maxillary and ethmoidal sinuses for ATA group, eosinophil counts were higher in ethmoidal sinus compared to that in maxillary sinus in the AIA group (P<.05). Eosinophil counts were higher in the maxillary than in ethmoidal sinuses for control patients (P<.05). Despite low correlation between eosinophil counts in peripheral blood and eosinophil counts in maxillary sinus (rs=0.4323, P<.001), moderate correlation was observed between eosinophil counts in peripheral blood and eosinophil counts in ethmoidal sinus (rs=0.5249, P<.0001). Basal U-LTE4 concentrations were higher in AIA patients than in those with aspirin-tolerant asthma. Despite low correlation between eosinophil counts and U-LTE4 concentration in maxillary sinus (rs=0.3849, P<.01), moderate correlation was observed between eosinophil counts and U-LTE4 concentrations in ethmoidal sinus (rs=0.4736, P<.001). CONCLUSION: We describe the differences in U-LTE4 and other parameters in AIA compared to ATA, and correlation among parameters. We demonstrate that eosinophil-dominant inflammation starts in ethmoidal sinus clinicopathogenetically in CRS with asthma. U-LTE4 concentration was not exclusively associated with eosinophil counts in ethmoidal sinus. Eosinophils in ethmoidal sinus may be a major production site for CysLTs, particularly in AIA. CRS with AIA is assumed to be characterized by leukotriene-eosinophil cross-interaction in ethmoidal sinus.

Aspirin provocation increases 8-iso-PGE2 in exhaled breath condensate of aspirin-hypersensitive asthmatics.

BACKGROUND: Isoprostanes are bioactive compounds formed by non-enzymatic oxidation of polyunsaturated fatty acids, mostly arachidonic, and markers of free radical generation during inflammation. In aspirin exacerbated respiratory disease (AERD), asthmatic symptoms are precipitated by ingestion of non-steroid anti-inflammatory drugs capable for pharmacologic inhibition of cyclooxygenase-1 isoenzyme. We investigated whether aspirin-provoked bronchoconstriction is accompanied by changes of isoprostanes in exhaled breath condensate (EBC). METHODS: EBC was collected from 28 AERD subjects and 25 aspirin-tolerant asthmatics before and after inhalatory aspirin challenge. Concentrations of 8-iso-PGF2α, 8-iso-PGE2, and prostaglandin E2 were measured using gas chromatography/mass spectrometry. Leukotriene E4 was measured by immunoassay in urine samples collected before and after the challenge. RESULTS: Before the challenge, exhaled 8-iso-PGF2α, 8-iso-PGE2, and PGE2 levels did not differ between the study groups. 8-iso-PGE2 level increased in AERD group only (p=0.014) as a result of the aspirin challenge. Urinary LTE4 was elevated in AERD, both in baseline and post-challenge samples. Post-challenge airways 8-iso-PGE2 correlated positively with urinary LTE4 level (p=0.046), whereas it correlated negatively with the provocative dose of aspirin (p=0.027). CONCLUSION: A significant increase of exhaled 8-iso-PGE2 after inhalatory challenge with aspirin was selective and not present for the other isoprostane measured. This is a novel finding in AERD, suggesting that inhibition of cyclooxygenase may elicit 8-iso-PGE2 production in a specific mechanism, contributing to bronchoconstriction and systemic overproduction of cysteinyl leukotrienes.

Aspirin-intolerant asthma (AIA) assessment using the urinary biomarkers, leukotriene E4 (LTE4) and prostaglandin D2 (PGD2) metabolites.

The clinical syndrome of aspirin-intolerant asthma (AIA) is characterized by aspirin/nonsteroidal anti-inflammatory drug intolerance, bronchial asthma, and chronic rhinosinusitis with nasal polyposis. AIA reactions are evidently triggered by pharmacological effect of cyclooxygenase-1 inhibitors. Urine sampling is a non-invasive research tool for time-course measurements in clinical investigations. The urinary stable metabolite concentration of arachidonic acid products provides a time-integrated estimate of the production of the parent compounds in vivo. AIA patients exhibits significantly higher urinary concentrations of leukotriene E(4) (LTE(4)) and 1,15-dioxo-9α-hydroxy-2,3,4,5-tetranorprostan-1,20-dioic acid (tetranor-PGDM), a newly identified metabolite of PGD(2), at baseline. This finding suggests the possibility that increased mast cell activation is involved in the pathophysiology of AIA even in a clinically stable condition. In addition, lower urinary concentrations of primary prostaglandin E(2) and 15-epimer of lipoxin A(4) at baseline in the AIA patients suggest that the impaired anti-inflammatory elements may also contribute to the severe clinical outcome of AIA. During the AIA reaction, the urinary concentrations of LTE(4) and PGD(2) metabolites, including tetranor-PGDM significantly and correlatively increase. It is considered that mast cell activation probably is a pathophysiologic hallmark of AIA. However, despite the fact that cyclooxygenease-1 is the dominant in vivo PGD(2) biosynthetic pathway, the precise mechanism underlying the PGD(2) overproduction resulting from the pharmacological effect of cyclooxygenease-1 inhibitors in AIA remains unknown. A comprehensive analysis of the urinary concentration of inflammatory mediators may afford a new research target in elucidating the pathophysiology of AIA.

Urinary concentrations of 15-epimer of lipoxin A(4) are lower in patients with aspirin-intolerant compared with aspirin-tolerant asthma.

BACKGROUND: Although an abnormality in arachidonic acid metabolism may be responsible for aspirin-intolerant asthma (AIA), there is little knowledge about the concentrations of urinary lipoxin A(4) (LXA(4)) and the 15-epimer of LXA(4) (15-epi-LXA(4)) in relation to asthma severity in AIA subjects. OBJECTIVE: The purpose of this study is to estimate urinary LXA(4) and the 15-epimer concentrations to investigate lipoxins in AIA. METHODS: In this study, we examined AIA, aspirin-tolerant asthma (ATA) and healthy control groups. The AIA and ATA groups were subdivided into the severe asthma and non-severe asthma subgroups. Urinary LXA(4), 15-epi-LXA(4) and leukotriene E(4) (LTE(4) ) were quantified using enzyme immunoassay after separating these compounds using high-performance liquid chromatography. RESULTS: The urinary LXA(4) concentration was significantly lower than the 15-epi-LXA(4) concentration in the asthmatic subjects. The AIA group showed significantly lower urinary 15-epi-LXA(4) (P < 0.01) and higher urinary LTE(4) concentrations (P < 0.05) than the ATA group. Comparison of 15-epi-LXA(4) concentrations between the severe asthmatic and non-severe asthmatic subjects in the AIA and ATA groups revealed that the decreased 15-epi-LXA(4) concentration may be related to aspirin intolerance, but not asthma severity. Receiver operator characteristic curves demonstrated that the concentration ratio of LTE(4) to 15-epi-LXA(4) was superior to 15-epi-LXA(4) concentration and LTE(4) concentration as a predictive factor for aspirin intolerance. CONCLUSIONS AND CLINICAL RELEVANCE: We have demonstrated for the first time that urinary 15-epi-LXA(4) concentration is significantly higher than LXA(4) concentration in both the AIA and ATA groups. 15-Epi-LXA(4) concentration was significantly lower in the AIA group with an increased urinary LTE(4) concentration than in the ATA group. An imbalance between proinflammatory cysteinyl-leukotrienes and anti-inflammatory 15-epi-LXA(4) may be involved in AIA pathogenesis.

Safety of parecoxib in asthmatic patients with aspirin-exacerbated respiratory disease.

BACKGROUND: Aspirin-exacerbated respiratory disease (AERD) affects a subset of patients with asthma. Cyclooxygenase 2 inhibitors are a safe alternative in patients with AERD. Parecoxib is the first cyclooxygenase 2 selective drug for parenteral administration, especially useful after surgery thanks to its analgesic power. The aim of the study is to assess the tolerance of parecoxib (Dynastat; Pfizer) given by intramuscular route in patients with AERD. METHODS: Patients evaluated were referred to the Pneumology and Respiratory Allergy Department of the Hospital Clinic (Barcelona, Spain) for asthma exacerbations precipitated by 2 or more different non-steroidal anti-inflammatory drugs (NSAIDs). AERD was confirmed by a nasal challenge test with aspirin. Patients were challenged with parecoxib, and urine samples were collected to measure the leukotriene E(4) concentration. RESULTS: Ten patients were challenged with parecoxib. No symptoms were reported with any of the administered doses, and there were no signs of immediate or delayed hypersensitivity. There were no alterations in the forced expiratory volume in 1 s or in acoustic rhinometry measurements. No significant differences between leukotriene E(4) levels were detected. CONCLUSION: The drug was well tolerated by all patients, with no adverse reactions. This lack of reactions found in our study supports the fact that parecoxib could be a safe alternative in postsurgery analgesia in NSAID-intolerant asthma patients.

Increase in salivary cysteinyl-leukotriene concentration in patients with aspirin-intolerant asthma.

BACKGROUND: Cysteinyl-leukotrienes (CysLTs; LTC4, LTD4, and LTE4) play a considerable role in the pathophysiology of aspirin-intolerant asthma (AIA). Saliva has recently been validated as novel, simple, and noninvasive method for investigating inflammation in patients with asthma. The aim of this study is to clarify the molecular species of CysLT in saliva and to evaluate the CysLT and LTB4 concentrations in saliva in AIA patients. We also examined how the CysLT concentration in saliva reflects that of their corresponding urinary metabolite. METHODS: We preformed an analytical cross-sectional study. CysLT and LTB4 concentrations in saliva were quantified by enzyme immunoassay (EIA) following purification by high-performance liquid chromatography (HPLC). RESULTS: 1. When analyzed by EIA in combination with HPLC, saliva was found to consist of LTC4, LTD4 and LTE4 in similar amounts. 2. In saliva analysis among the three groups (AIA patients, aspirin-tolerant asthma [ATA] patients, and healthy subjects), both the concentrations of CysLTs and LTB4 were significantly higher in AIA patients than in ATA patients and healthy subjects. 3. We found significant correlations between CysLT concentration and LTB4 concentration in saliva in each group. 4. No significant correlation was found between the concentration of LTE4 in urine and that of CysLTs in saliva. CONCLUSIONS: In this study, we found higher concentrations of CysLTs and LTB4 in saliva from AIA patients than in saliva from ATA patients, suggesting that the quantification of CysLT and LTB4 concentrations in saliva may be another diagnostic strategy for AIA.