Urinary leukotriene E4 and 9α, 11β-prostaglandin F2 concentrations in mild, moderate and severe asthma, and in healthy subjects

BACKGROUND: Airway inflammation in asthma is associated with cysteinyl leukotriene and prostaglandin D(2) production. Measurement of urinary metabolites of these eicosanoids may be useful for monitoring asthma patients. However, the influence of asthma phenotype and severity on basal urinary excretion of these metabolites is unknown. OBJECTIVE: To compare urinary leukotriene (LT)E(4) and 9 alpha, 11 beta-prostaglandin (PG)F(2) concentrations in large groups of mild, moderate and severe asthmatic patients and healthy control subjects. METHODS: Asthma severity, treatment and aspirin sensitivity were assessed by questionnaire in 168 asthmatic patients. Basal LTE(4) and 9 alpha, 11 beta-PGF(2) concentrations were measured in urine samples from these patients and from 175 control subjects using enzyme immunoassays. RESULTS: Urinary LTE(4) was correlated with 9 alpha, 11 beta-PGF(2) in both control subjects and asthmatic patients (P<0.002). Median LTE(4) and 9 alpha, 11 beta-PGF(2) concentrations in patients with severe asthma were significantly reduced compared with mild asthmatic patients (P<0.05 and <0.001, respectively). Urinary 9 alpha, 11 beta-PGF(2), but not LTE(4) was lower in asthmatic patients using inhaled corticosteroids (P<0.02). Multiple regression analysis indicated that urinary 9 alpha, 11 beta-PGF(2) concentration was negatively correlated with asthma severity (P=0.003) and also with % predicted FEV(1) (forced expiratory volume in 1 s) (P=0.005). CONCLUSIONS: Baseline urinary LTE(4) and 9 alpha, 11 beta-PGF(2) concentrations are of limited value in discriminating between patients with different severities of asthma. Reduced urinary LTE(4) and 9 alpha, 11 beta-PGF(2) in patients with severe asthma suggest that direct or indirect effects of high-dose corticosteroid therapy combined with other factors associated with severe asthma may influence eicosanoid production. However, the negative association of urinary 9 alpha, 11 beta-PGF(2) with lung function suggests an adverse effect of chronic PGD(2) production on lung function in asthma, irrespective of severity.     

Possible involvement of mast-cell activation in aspirin provocation of aspirin-induced asthma

BACKGROUND: Although there is increasing evidence of the importance of cysteinyl leukotrienes (LT) as mediators of aspirin-induced bronchoconstriction in aspirin-sensitive asthma, the cellular origin of the LT is not yet clear. METHODS: Urinary concentrations of leukotriene E4 (LTE4), 11-dehydrothromboxane B2, 9alpha,11beta-prostaglandin F2, and Ntau-methylhistamine were measured during the 24 h following cumulative intravenous administration of increasing doses of lysine aspirin to asthmatic patients. In addition, the urinary concentrations of these metabolites were measured on 5 consecutive days in a patient who suffered an asthma attack after percutaneous administration of nonsteroidal anti-inflammatory drugs. RESULTS: In aspirin-induced asthma patients (AIA, n=10), the basal concentration of urinary LTE4, but not the other metabolites, was significantly higher than that in aspirin-tolerant asthma patients (ATA, n=10). After intravenous aspirin provocation, the AIA group showed a 13.1-fold (geometric mean) increase in excretion of LTE4 during the first 3 h, and 9alpha,11beta-prostaglandin F2 also increased in the AIA group during the first 0-3 h and the 3-6 h collection period. Ntau-methylhistamine excretion was also increased, but to a lesser degree. Administration of aspirin caused significant suppression of 11-dehydrothromboxane B2 excretion in both the AIA and ATA groups. When the percentage of maximum increase of each metabolite from the baseline concentrations was compared between the AIA group and the ATA group, a significantly higher increase in excretion of LTE4, 9alpha,11beta-prostaglandin F2, and Ntau-methylhistamine was observed in the AIA group than the ATA group. An increased excretion of LTE4 and 9alpha,11beta-prostaglandin F2 has been detected in a patient who suffered an asthma attack after percutaneous administration of nonsteroidal anti-inflammatory drugs. CONCLUSIONS: Considering that human lung mast cells are capable of producing LTC4, prostaglandin D2, and histamine, our present results support the concept that mast cells, at least, may participate in the development of aspirin-induced asthma.     

Effects of pranlukast on aspirin-induced bronchoconstriction: differences in chemical mediators between aspirin-intolerant and tolerant asthmatic patients.

BACKGROUND: Aspirin inhibits cyclooxygenase activity and modifies production of the arachidonate cascade in aspirin-induced asthma. The aim of the present study was to examine the effects of leukotriene (LT) receptor antagonist on aspirin challenge on eosinophil activity and chemical mediators released into the airway of asthmatic patients. METHODS: Aspirin oral provocation test was performed in aspirin-intolerant asthmatic patients (AIA; N = 7) and aspirin-tolerant asthmatic patients (ATA; N = 7). In AIA, LT receptor antagonist (pranlukast) was administered orally 2 hours before the test, and its inhibitory effects on sputum LTC4+C4, eosinophil cationic protein (ECP), eosinophil count, urinary LTE4/creatinine (Cr), 11-dehydrothromboxane (11-dhTX) B2/Cr, serum LTC4+D4, ECP, and peripheral blood eosinophil count were compared with the findings in ATA subjects. RESULTS: In AIA, aspirin induced an immediate reaction associated with increased urinary LTE4/Cr and sputum ECP and a fall in urinary 11-dhTXB2/Cr. Pranlukast inhibited the bronchial reaction and an increase in sputum ECP after threshold dosed of ASA, but failed to change aspirin-induced LT production in sputum and urine. In ATA, aspirin challenge was only associated with a fall in urinary 11-dhTXB2. CONCLUSIONS: Our results indicated that aspirin-induced asthma is associated with overproduction of LT with a shift to the 5-lipoxygenase series of the arachidonate cascade and that leukotriene receptor antagonist are useful for AIA through inhibition of production of LT and eosinophilic inflammation in the airway.     

A comparative study of eicosanoid concentrations in sputum and urine in patients with aspirin-intolerant asthma

BACKGROUND: Although many studies have assumed that the overproduction of cysteinyl- leukotrienes (cys-LTs) and an imbalance of arachidonic acid metabolism may be plausible causes for the pathogenesis of aspirin-intolerant asthma (AIA), there has been little experimental evidence to substantiate this notion in lower airways of patients with AIA. OBJECTIVES: The purpose of this study was to compare the eicosanoid concentrations in sputum and urine from patients with AIA. METHODS: The concentrations of sputum cys-LTs, prostaglandin E2 (PGE2), PGF2alpha, PGD2 and thromboxane B2 were measured to assess local concentrations of eicosanoids in patients with AIA and in those with aspirin-tolerant asthma (ATA). The concentrations of two urinary metabolites, leukotriene E4 (LTE4) and 9alpha11betaPGF2, were also measured to corroborate the relationship between the eicosanoid biosynthesis in the whole body and that in lower airways. RESULTS: The concentration of PGD2 in sputum was significantly higher in patients with AIA than in those with ATA (median, 5.3 pg/mL vs. 3.1 pg/mL, P < 0.05), but there was no significant difference in the concentration of the corresponding metabolite, 9alpha11betaPGF2, between the two groups. No differences were noted in the concentrations of other prostanoids in sputum between the two groups. The sputum cys-LT concentrations showed no differences between the two groups, in spite of the observation that the concentration of urinary LTE4 was significantly higher in patients with AIA than in those with ATA (median, 195.2 pg/mg-cre vs. 122.1 pg/mg-cre, P < 0.05). There was a significant correlation among the concentration of cys-LTs, the number of eosinophils and the concentration of eosinophil-derived neurotoxin (EDN) in sputum. CONCLUSION: The urinary concentration of LTE4 does not necessary reflect cys-LT biosynthesis in lower airways. A significantly higher concentration of PGD2 in sputum from patients with AIA suggests the possible ongoing mast cell activation in lower airways.     

Clinical features of asthmatic patients with increased urinary leukotriene E4 excretion (hyperleukotrienuria): Involvement of chronic hyperplastic rhinosinusitis with nasal polyposis

BACKGROUND: The urinary leukotriene E4 (U-LTE4) concentration is significantly increased in patients with aspirin-intolerant asthma (AIA). However, the relationship between the clinicopathogenetic factors of asthma and the U-LTE4 concentration remains undetermined. OBJECTIVE: We sought to examine the clinical features of asthmatic patients with increased excretion levels of U-LTE4 (hyperleukotrienuria). METHODS: We measured the U-LTE4 concentrations in 137 asthmatic patients (including 64 patients with AIA) who were in clinically stable condition. A U-LTE4 concentration of 150 pg/mg creatinine or greater (mean U-LTE4 + 3 SDs of normal healthy control subjects) was indicative of hyperleukotrienuria. RESULTS: The basal concentration of U-LTE4 was significantly higher in the patients with AIA than in those with aspirin-tolerant asthma (ATA; median, 227.2 vs 90.3 pg/mg creatinine; P <.01). Compared with normal leukotrienuria in the patients with AIA, hyperleukotrienuria in the patients with AIA was associated with older age and decrease in pulmonary function. On the other hand, compared with normal leukotrienuria in the patients with ATA, hyperleukotrienuria in the patients with ATA was associated with severe asthma and chronic hyperplastic rhinosinusitis with nasal polyposis (CHRS/NP), which are well-known symptoms of the aspirin triad, as well as hypereosinophilia and anosmia. The patients with ATA with CHRS/NP excreted U-LTE4 at significantly high concentrations. There were significant decreases in the U-LTE4 concentrations before and after the sinus surgery in both the AIA and ATA groups (P <.05). CONCLUSION: Cysteinyl leukotrienes are not strictly associated with aspirin intolerance itself but rather with clinical features, such as CHRS/NP, that are similar to those seen in AIA. CHRS/NP might be involved in cysteinyl leukotriene overproduction in asthmatic patients.     

Exhaled eicosanoids following oral aspirin challenge in asthmatic patients

BACKGROUND: Biochemical analysis of expiratory breath condensate is an emerging non-invasive technique for assessment of airway inflammation. OBJECTIVE: We wondered whether application of expiratory breath condensate could facilitate diagnosis of aspirin-intolerant asthma and reproduce eicosanoids mediators' abnormalities described in this disease. METHODS: We measured prostaglandins (PGs) E(2), F(2 alpha), 9 alpha 11 beta F(2) and iso-F(2) by gas-chromatography/mass-spectrometry and cysteinyl leukotrienes (cys-LTs) by radioimmunoassay in breath condensates of asthmatic patients undergoing oral aspirin challenge. Fourteen patients with aspirin-induced asthma and 20 aspirin-tolerating asthmatics, most of them on chronic inhaled corticotherapy, were studied and compared with 10 healthy subjects. Additionally, plasma 9 alpha 11 beta PGF(2), the metabolite of PGD(2) and urinary leukotriene (LT) E(4) were measured before and following the challenge. RESULTS: At baseline, PG did not differ between the groups, except for lower 9 alpha 11 beta PGF(2) in aspirin-intolerant asthma. Their concentrations were not changed by the challenge. Breath condensate cys-LTs were similar in the groups studied at base, and after aspirin challenge increased only in aspirin-intolerant patients. Elevated baseline urinary LTE(4) and its further increase following aspirin challenge was highly diagnostic for aspirin-intolerant asthma. The discriminatory value of cys-LTs increase in breath condensates was lower (72.8%) than either basal (99%) or post-challenge increase (94%) of urinary LTE(4). CONCLUSIONS: In asthmatic patients on chronic corticotherapy measurement of urinary LTE(4) excretion rather than cys-LTs in breath condensate is of greater value for diagnosis of aspirin hypersensitivity.     

Specific immunoglobulin E for staphylococcal enterotoxins in nasal polyps from patients with aspirin-intolerant asthma

BACKGROUND: Nasal polyps infiltrated with eosinophils are commonly found in chronic asthmatic patients, more frequently in those with aspirin-intolerant asthma (AIA) than aspirin-tolerant asthma (ATA). Some studies have suggested a contribution of superantigens derived from Staphylococcus sp to nasal polyposis and eosinophilia, but their relative importance in AIA and ATA subjects is unknown. OBJECTIVE: We investigated whether local production of specific IgE to staphylococcal enterotoxins A and B (SEA and SEB) and relationships with markers of eosinophilic inflammation differ in the nasal polyps of AIA and ATA subjects. METHODS: Fifteen AIA subjects with positive responses to lysine-aspirin bronchoprovocation and 15 ATA subjects underwent polypectomy. Immunoassays were used to quantify eosinophil cationic protein (ECP), IL-5, mast cell tryptase, soluble IL-2 receptors (sIL-2R), total IgE, and specific IgE for SEA and SEB. RESULTS: ECP levels in nasal polyp homogenates were higher in AIA subjects than in ATA subjects (P < 0.02), with no significant differences in tryptase, IL-5 or sIL-2R. Total IgE, and specific IgE to both SEA and SEB, were detectable in some nasal polyps from both subject groups, but median levels were markedly higher in AIA subjects than in ATA subjects (P = 0.04, 0.01, 0.05, respectively). Levels of specific IgE to SEA and SEB correlated significantly with levels of ECP and IL-5, but not those of tryptase or sIL-2R. CONCLUSION: These findings suggest that staphylococcal superantigens may drive local eosinophilic inflammation in nasal polyp tissue, and that this is exacerbated in subjects with AIA.     

Safety of a specific COX-2 inhibitor in aspirin-induced asthma

In a subset of patients with asthma, aspirin and several other non-steroidal anti-inflammatory drugs (NSAID) that inhibit simultaneously cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) precipitate dangerous asthmatic attacks. We tested the hypothesis that in patients with aspirin-induced asthma the attacks are triggered by inhibition of COX-1 and not COX-2. In twelve asthmatic patients (seven men, five women, average age 39 years) oral aspirin challenge precipitated symptoms of bronchial obstruction with fall in FEV1 > 20%, and a rise in urinary leukotriene E4 (LTE4) excretion; also in five patients the stable metabolite of PGD2, 9alpha11betaPGF2, increased in urine. The patients then entered a double-blind, placebo-controlled, cross-over study in which they received either placebo or rofecoxib in increasing doses 1.5-25.0 mg for 5 consecutive days, separated by a 1-week wash-out period. No patient on rofecoxib developed dyspnoea or fall in FEV1 > 20%; mean urinary LTE4 and 9alpha11betaPGF2 urinary levels, measured on each study day for 6 h post-dosing, remained unchanged. Two patients on placebo experienced moderate dyspnoea without alterations in urinary metabolites excretion. At least 2 weeks after completion of the study, all patients received on an open basis 25 mg rofecoxib without any adverse effects. NSAID that inhibit COX-1, but not COX-2, trigger asthmatic attacks in patients with asthma and aspirin intolerance. Rofecoxib can be administered to patients with aspirin-induced asthma.     

Deficient prostaglandin E2 production by bronchial fibroblasts of asthmatic patients,with special reference to aspirin-induced asthma

BACKGROUND: Regulation of prostaglandin synthesis and the activation of human airway fibroblasts associated with the remodeling of the bronchi play an important role in asthma. OBJECTIVE: We sought to assess the cyclooxygenase pathways in airway fibroblasts of patients with bronchial asthma. METHODS: Generation of prostaglandin E(2) (PGE(2)) and pros-taglandin D(2) (PGD(2)) by bronchial fibroblasts was measured by means of mass spectrometry in culture supernatants, and cyclooxgenases expression was estimated by means of RT-PCR and immunoblotting. The cells were isolated from 3 groups of subjects: nonasthmatic patients (n = 10), patients with aspirin-tolerant asthma (ATA, n = 9), and patients with aspirin-intolerant asthma (AIA, n = 7). RESULTS: The cytomix (LPS, 5 square g/mL; IL-1 square, 5 ng/mL; and TNF- square, 10 ng/mL; 18 hours) stimulated the production of prostaglandins. Asthmatic patients were characterized by low capacity to produce PGE(2) after cytomix stimulation. In the nonasthmatic patient group the mean PGE(2) production was 32 +/- 33 ng/mL (35-fold of the basic production), in the ATA group it was 16 +/- 18 ng/mL (16-fold), and in the AIA group it was only 5.3 +/- 3.6 ng/mL (4-fold). The mean concentration of PGD(2) for nonasthmatic patients, patients with ATA, and patients with AIA was 0.18 +/- 0.16 ng/mL (4.7-fold of the basic production), 0.18 +/- 0.14 ng/mL (4.2-fold), and 0.235 +/- 0.19 ng/mL (1.9-fold), respectively. The observed difference was not due to insufficient cyclooxygenase 2 expression because all groups had similar levels of its mRNA and protein. The patients with AIA had low expression levels of cyclooxygenase 1 protein but not of its mRNA. The PGE(2)/PGD(2) concentration ratio increased after cytomix stimulation in all groups but was significantly less in patients with AIA than in patients with ATA. CONCLUSIONS: Our results point to a deficient PGE(2) production under proinflammatory conditions in asthmatic airways. This could weaken local defensive mechanisms and promote cysteinyl leukotriene overproduction.     

Increase in urinary leukotriene B4 glucuronide concentration in patients with aspirin-intolerant asthma after intravenous aspirin challenge

BACKGROUND: Aspirin challenge of aspirin-intolerant asthma (AIA) patients causes a significant increase in leukotriene E4 (LTE4) concentration in urine. However, knowledge on leukotriene B4 (LTB4) generation in patients with AIA is insufficient. Recent research has demonstrated that exogenously administered LTB4 is excreted as glucuronide into the urine in human healthy subjects. OBJECTIVE: The purpose of this study is to estimate urinary LTB4 glucuronide (LTBG) concentration in the clinically stable condition in healthy subjects and asthmatic patients and to investigate changes in urinary LTBG concentration in patients with AIA after aspirin challenge. METHODS: A provocation test was performed by intravenous aspirin challenge. After urine was hydrolysed by beta-glucuronidase, the fraction containing LTB4 was purified by high-performance liquid chromatography and LTB4 concentration was quantified by enzyme immunoassay. Urinary LTBG concentration was calculated as the difference between the concentration obtained with hydrolysis and that without hydrolysis. RESULTS: (1) After hydrolysis, the presence of urinary LTB4 was verified by gas chromatography-mass spectrometry-selected ion monitoring. (2) The urinary LTBG concentration was significantly higher in the asthmatic patients than in the healthy subjects (median, 5.37 pg/mg creatinine [range 1.2-13] vs. 3.32 pg/mg creatinine [range, 0.14-10.5], P = 0.0159). (3) The patients with AIA (n = 7), but not those with aspirin-tolerant asthma (n = 6), showed significant increases in LTBG and LTE4 excretions after aspirin challenge. (4) When the concentrations after aspirin challenge were analysed simultaneously, a significant linear correlation was observed between urinary LTBG concentration and urinary LTE4 concentration in patients with AIA (Spearman's rank correlation test, r = 0.817, P = 0.0003). CONCLUSION: LTBG is present in human urine, albeit at a concentration lower than urinary LTE4. In addition to a marked increase in cysteinyl-leukotriene production, aspirin challenge induced LTB4 production in AIA patients.     

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

BACKGROUND: Aspirin-induced asthma/rhinitis (AIAR) is characterized by the altered metabolism of leukotrienes and proinflammatory prostaglandins. The basal and postchallenge levels of eicosanoids might reflect the clinical and biochemical characteristics of patients with distinct types of hypersensitive responses to aspirin. OBJECTIVE: We compared clinical and eicosanoid profiles of patients with AIAR showing both bronchial and nasal versus isolated nasal responses to aspirin challenge. METHODS: Twenty-three patients with AIAR underwent the single-blind, oral, placebo-controlled aspirin challenge. The bronchial response (BR) was evidenced by dyspnea and spirometry, whereas the nasal response (NR) was evidenced by nasal symptoms and acoustic rhinometry and/or rhinomanometry. Urinary leukotriene E4 (uLTE4), serum and urinary stable prostaglandin D2 metabolite, and 9alpha,11beta-prostaglandin F2 (9alpha,11beta-PGF2), were determined at baseline and after the aspirin challenge. RESULTS: Fifteen subjects showed BR and NR (BNR), whereas 8 showed NR only. Basal uLTE4 in the BNR group was significantly higher than in the NR group. After aspirin challenge, it increased significantly in both groups. Serum 9alpha,11beta-PGF2 increased after aspirin challenge in the BNR group only. The patients with BNR had more severe AIAR. CONCLUSIONS: BNR to aspirin in AIAR indicates a more advanced disease and more profound underlying eicosanoid metabolism disturbances.     

Serum interleukin-5 in aspirin-induced asthma

BACKGROUND: Eosinophilopoetic cytokine IL-5 enhances cysteinyl-leukotriene (cys-LT) synthesis in eosinophils in vitro. In patients with aspirin-induced asthma (AIA) bronchial biopsies revealed eosinophil infiltration and a marked increase in IL-5 positive cells. OBJECTIVE: We wondered whether in AIA patients the bronchial IL-5 increase is reflected in peripheral blood, and if so, whether it is related to overproduction of cys-LT. METHODS: In 11 stable patients with AIA, 32 with ATA (aspirin-tolerant asthma) and in 16 controls we measured serum IL-5 concentrations and urinary LTE4, believed to reflect global cys-LT production. RESULTS: Serum IL-5 was detectable in 12 of 43 asthmatics, but in none of the control subjects. It was highest in the ATA group and differed significantly from the controls. There was no significant difference in IL-5 levels between: (i) the asthmatic groups studied, and (ii) AIA patients and controls. No relationship was found between serum IL-5 and urinary cys-LT. CONCLUSION: Overexpression of IL-5 reported in the airways of aspirin-sensitive patients with asthma was not reflected in their blood. If IL-5 affects cys-LT production, it is rather in the bronchi of the patients than in the blood.     

Release of prostaglandin D2 and leukotriene C4 in response to hyperosmolar stimulation of mast cells

BACKGROUND: Mannitol-induced bronchoconstriction in subjects with exercise-induced asthma is associated with increased urinary excretion of 9alpha, 11beta-PGF(2), a metabolite of prostaglandin D(2) (PGD(2)) serving as a mast cell marker. It has however been questioned whether or not human mast cells release PGD(2) and leukotriene C(4) (LTC(4)) after osmotic challenge with mannitol in vitro. METHODS: Cord blood-derived human mast cells were stimulated osmotically, immunologically or with a combination of both. Supernatants were analysed for PGD(2), LTC(4) and histamine contents with enzyme immunoassays. RESULTS: Significant release of de novo synthesized eicosanoids, predominantly PGD(2) [12 (8.8, 14) pmol/10(6)cells; median (25th, 75th percentile) but also LTC(4) (0.1 (0.08, 0.15) pmol/10(6) cells] were found in mast cells in vitro in response to 0.7 M mannitol stimulation. A massive release of histamine [70 (5.3)% of total; mean (SEM)] was also found. There were no correlations between the levels of released mediators after mannitol stimulation. In contrast, there was a correlation between release of PGD(2) and LTC(4), following immunological stimulation. CONCLUSION: The findings support that hyperosmolar challenge activates mast cells, but different than antigen stimulation.     

Urinary 3-bromotyrosine and 3-chlorotyrosine concentrations in asthmatic patients: lack of increase in 3-bromotyrosine concentration in urine and plasma proteins in aspirin-induced asthma after intravenous aspirin challenge

BACKGROUND: Eosinophil peroxidase and myeloperoxidase halogenate tyrosine residues in plasma proteins and generate 3-bromotyrosine (BY) and 3-chlorotyrosine (CY), respectively. OBJECTIVES: (1) To estimate urinary concentrations of BY and CY in asthmatic patients. (2) To investigate BY concentration in relation to urinary leukotriene E4 (LTE4) concentration in order to evaluate the activation of eosinophils in patients with aspirin-induced asthma (AIA). METHODS: BY and CY were quantified with a gas chromatograph-mass spectrometer using (13)C-labelled compounds as internal standards. RESULTS: (1) Activation of eosinophils and neutrophils by immobilized IgG1 induced preferential formation of BY and CY, respectively. (2) A significantly higher concentration of BY was observed in the urine from asthmatic patients than in that from healthy control subjects (45+/-21.7 vs. 22.6+/-10.8 ng/mg-creatinine, P<0.01). CY concentration was also elevated in the urine from asthmatic patients (4.4+/-3.2 vs. 1.5+/-1.0 ng/mg-creatinine, P<0.01). (3) After intravenous aspirin challenge of aspirin-induced asthmatic patients, the concentration of BY in urine did not significantly change. No significant change was also observed in the ratio of BY concentration to total tyrosine concentration in plasma proteins. In contrast, the concentration of urinary LTE4 significantly increased after the intravenous aspirin challenge. CONCLUSION: Determination of BY and CY concentrations may be useful for monitoring the activation of eosinophils and neutrophils in asthmatic patients, respectively. After aspirin challenge of AIA patients, the increased concentration of urinary LTE4 did not accompany changes in BY concentration in both urine and plasma proteins. These results may preclude the activation of eosinophils after aspirin challenge in patients with AIA.     

PGE suppresses excessive anti-IgE induced cysteinyl leucotrienes production in mast cells of patients with aspirin exacerbated respiratory disease

BACKGROUND: Aspirin causes bronchospasm in patients with aspirin exacerbated respiratory disease (AERD). The contribution of mast cells to the increased cysteinyl-leucotrienes (cys-LTs) detected in AERD patients is however not defined. AIMS OF THE STUDY: Effects of prostaglandin (PG) E(2) and inhibitors of cyclooxygenase (COX) and lipoxygenase (LO) pathways on mediator release from cultured mast cells of normal subjects, aspirin tolerant asthma (ATA) and AERD patients were compared to better define the role of mast cells in AERD. METHODS: Mast cells were cultured from peripheral blood progenitors and were activated by anti-IgE. Histamine, PGD(2) and cys-LTs released were then determined. RESULTS: Basal release of all three mediators was similar in all subjects. Although the release of all three mediators was increased by anti-IgE, mast cells from AERD patients produced significantly more cys-LTs (6.9 +/- 2.0 ng/10(6) cells) than normal and ATA subjects (2.3 +/- 0.8 and 1.7 +/- 0.5 ng/10(6) cells, respectively). While COX and LO pathway inhibitors did not affect anti-IgE induced histamine release, they significantly suppressed the production of PGD(2) and cys-LTs, respectively, in all patients. PGE(2) significantly enhanced anti-IgE induced histamine and PGD(2) release from mast cells of normal subjects but not those of ATA and AERD patients. In contrast, PGE(2) suppressed only anti-IgE induced cys-LTs release from mast cells of AERD patients. CONCLUSION: We speculate that overproduction of cys-LTs is unique to mast cells of AERD patients and is particularly sensitive to suppression by PGE(2). Consequently reduction of PGE(2) production by aspirin removes this endogenous control of cys-LTs overproduction, resulting in asthma attack.     

Gene-expression profiles in human nasal polyp tissues and identification of genetic susceptibility in aspirin-intolerant asthma

Background Aspirin‐intolerant asthma (AIA) is a subtype of asthma induced by non‐steroidal anti‐inflammatory drugs and characterized by an aggressive mucosal inflammation of the lower airway (asthma) and the upper airways (rhinitis and nasal polyp). The lower airway lesion and the nasal polyp in AIA are postulated to have common pathogenic features involving aspirin sensitivity that would be reflected in the gene expression profile of AIA polyps. Objective This study was conducted to clarify the pathogenesis of AIA using gene expression analysis in nasal polyps, and identify genetic susceptibilities underlying AIA in a case–control association study. Methods Global gene expression of nasal polyps from nine AIA patients was examined using microarray technology in comparison with nasal polyps from five eosinophilic sinusitis (ES) patients, a related disease lacking aspirin sensitivity. Based on the AIA‐specific gene expression profile of nasal polyp, candidate genes for AIA susceptibility were selected and screened by a case–control design of 219 AIA patients, 374 non‐asthmatic control (CTR), and 282 aspirin‐tolerant asthmatic (ATA) subjects. Results One hundred and forty‐three elevated and three decreased genes were identified as AIA‐specific genes that were enriched in immune response according to Gene Ontology analysis. In addition, a k‐means‐based algorithm was applied to cluster the genes, and a subclass characteristic of AIA comprising 18 genes that were also enriched in immune response was identified. By examining the allelic associations of single nucleotide polymorphisms (SNPs) of AIA candidate genes relevant to an immune response with AIA, two SNPs, one each of INDO and IL1R2, showed significant associations with AIA (P=0.011 and 0.026 after Bonferroni's correction, respectively, in AIA vs. CTR). In AIA–ATA association analysis, modest associations of the two SNPs with AIA were observed. Conclusion These results indicate that INDO and IL1R2, which were identified from gene expression analyses of nasal polyps in AIA, represent susceptibility genes for AIA.     

Leukotriene C4 synthase promoter polymorphism in Japanese patients with aspirin-induced asthma

BACKGROUND: The A to C transversion in the promoter region of the gene encoding leukotriene C4 synthase (LTC4S) is proposed to be associated with the development of aspirin-induced asthma (AIA). OBJECTIVE: We investigated the frequency of the polymorphism in Japanese population and its association with clinical characteristics and cysteinyl leukotriene production. METHODS: Genotyping of LTC4S gene promoter was performed on 60 patients with AIA, 100 patients with aspirin-tolerant asthma (ATA), and 110 control subjects. We assessed the basal levels of urinary LTE4, the increment of urinary LTE4 on venous aspirin challenge, and LTC4S activity in peripheral blood eosinophils. RESULTS: The frequency of the variant C allele was significantly higher in patients with AIA (frequency of allele [q] = 0.192) than in patients with ATA (q = 0.110, P =.042). Variant C-allelic carriers experienced asthma at a significantly younger age (31.8 +/- 2.9 years [mean +/- SEM]) than wild-type A homozygotes (41.3 +/- 2.2 years, P =.007). Basal levels of LTE4 and the increment of urinary LTE4 on venous aspirin challenge did not show a difference between wild-type A homozygotes and variant C-allelic carriers. There was no relationship between the polymorphism and the LTC4S activity in eosinophils, although LTC4S activities were significantly higher in patients with AIA than in patients with ATA. CONCLUSION: Our findings reveal the lack of functionality of the polymorphism in the LTC4S gene, whereas this polymorphism might have some effect on the development of AIA, probably in linkage disequilibrium with another causatively important mutation.     

Release of cysteinyl leukotrienes with aspirin stimulation and the effect of prostaglandin E2 on this release from peripheral blood leucocytes in aspirin-induced asthmatic patients

BACKGROUND: The decrease in prostaglandin E(2) (PGE(2)) release due to aspirin (ASA)-induced cyclooxygenase inhibition and the increment in cysteinyl leukotriene (Cys-LT) release secondary to the removal of the inhibitory effect of PGE(2) on Cys-LT release have been suggested in the pathogenesis of aspirin-induced asthma (AIA). OBJECTIVE: In this study, we aimed to investigate the in vitro release of Cys-LT and to determine the effect of PGE(2) on Cys-LT release from peripheral blood leucocytes of patients with AIA after stimulation by ASA. PATIENTS AND METHODS: Patients with AIA (n = 13), patients with ASA-tolerant asthma (ATA) (n = 12) and healthy volunteers as controls (n = 13) were included to the study. ASA and PGE2 at three different concentrations were applied to the peripheral blood leucocytes of the study group, and Cys-LT levels following stimulants were assessed by enzyme immunoassay method. RESULTS: There was no difference in baseline Cys-LT levels between groups (AIA 353.4 +/- 55.5 pg/mL, ATA 354.7 +/- 40.3 pg/mL, and control group 368.5 +/- 30.2 pg/mL; P > 0.05). Though not present in other groups, the Cys-LT level of 453.6 +/- 70.0 pg/mL following ASA stimulation was higher than baseline in patients with AIA (P = 0.04). When PGE(2) was added to the ASA-stimulated samples of patients with AIA, Cys-LT levels were measured as 298.7 +/- 78.6 pg/mL, 279.8 +/- 79.9 pg/mL, and 243.4 +/- 51.3 pg/mL at PGE(2) 10(-7) m, 10(-6) m and 10(-5) m concentrations, respectively. These levels were lower than the ASA-stimulated Cys-LT values (P = 0.03, P = 0.01 and P = 0.01, respectively). The inhibitory effect of different PGE(2) concentrations on Cys-LT release was also present in patients with ATA and in controls. CONCLUSION: The increase in Cys-LT levels following ASA stimulation seems to be unique to AIA, which was not present in patients with ATA and in healthy controls. The inhibitory effect of PGE(2) on stimulated Cys-LT levels is another important finding to elucidate the role of PGE(2) in the pathogenesis of AIA.     

Increased production of cysteinyl leukotrienes and prostaglandin D2 during human anaphylaxis

Background Anaphylaxis is a life‐threatening syndrome resulting from the sudden release of mast cell‐ and basophil‐derived mediators into the circulation. However, pathological evidence of the association between inflammatory mediators and human anaphylaxis is insufficient. Objective The aim of this study was to better understand the relationship between in vivo production of inflammatory mediators and the pathogenesis of anaphylaxis. We also sought to evaluate mast cell activation in anaphylaxis. Methods We measured the concentrations of various inflammatory mediators in urine samples, which were collected from 32 anaphylactic patients during the onset of anaphlaxis and during clinical remission, 21 patients with asthma on acute exacerbation and 15 healthy control subjects. Blood and urine specimens were collected from the patients after provocation test. Urinary leukotriene E4 (LTE4), 9α, 11β‐prostaglandin F2 (9α, 11β‐PGF2), eosinophil‐derived neurotoxin (EDN) and leukotriene B4 glucuronide (LTBG) concentrations were determined by enzyme immunoassay, and the activity of plasma platelet‐activating factor acetylhydrolase and serum tryptase concentration were measured using commercially available kits. Results Significantly higher concentrations of urinary LTE4 and 9α, 11β‐PGF2, which immediately decreased during clinical remission, were observed in the anaphylactic patients than in asthmatic patients on acute exacerbation and healthy control subjects. Concentrations of EDN and LTBG were not significantly different among the anaphylactic patients, asthmatic patients on acute exacerbation and healthy subjects. There was a significant correlation between urinary LTE4 and 9α, 11β‐PGF2 concentrations in the anaphylactic patients (r=0.672, P=0.005, n=32). In addition, LTE4 concentration in patients with anaphylactic shock is significantly elevated compared with that in patients without anaphylactic shock. Conclusions This is a report on the significant increase in urinary LTE4 and 9α, 11β‐PGF2 concentrations during anaphylaxis. Urinary LTE4 and 9α, 11β‐PGF2 concentrations may be a reliable marker of endogenous production of inflammatory mediators associated with anaphylaxis.