Aspirin-intolerant Asthmatics Research Articles

Fatty Acid Composition of Cultured Fibroblasts Derived from Healthy Nasal Mucosa and Nasal Polyps

Background: Fibroblasts from nasal polyps (NP) of asthma patients have reduced expression of cyclooxygenase 2 (COX-2) and production of prostaglandin E2 (PGE2). We hypothesized that the reported alterations are due to alterations in the availability of arachidonic acid (AA). Objective: The objective was to determine the fatty acid composition of airway fibroblasts from healthy subjects and from asthma patients with and without aspirin intolerance. Methods: We analyzed the fatty acid composition of cultured fibroblasts from non-asthmatics (n = 6) and from aspirin-tolerant (n = 6) and aspirin-intolerant asthmatics (n = 6) by gas chromatography-flame ionization detector. Fibroblasts were stimulated with acetyl salicylic acid (ASA). Results: The omega-6 fatty acids dihomo-gamma-linolenic acid (C20:3) and AA (C20:4), and omega-3 fatty acids docosapentaenoic acid (DPA) (C22:5) and docosahexaenoic acid (DHA) (C22:6) were significantly higher in NP fibroblasts than in fibroblasts derived from nasal mucosa. The percentage composition of the fatty acids palmitic acid (C16:0) and palmitoleic acid (C16:1) was significantly higher in fibroblasts from patients with NP and aspirin intolerance than in fibroblasts derived from the nasal NP of aspirin-tolerant patients. ASA did not cause changes in either omega-3 or omega-6 fatty acids. Conclusions. Our data do not support the hypothesis that a reduced production of AA in NP fibroblasts can account for the reported low production of PGE2 in nasal polyps. Whether the increased proportion of omega-3 fatty acids can contribute to reduced PGE2 production in nasal polyps by competitively inhibiting COX-2 and reducing the amount of AA available to the COX-2 enzyme remains to be elucidated.

The Influence of Aspirin on Release of Eoxin C4, Leukotriene C4 and 15-HETE, in Eosinophilic Granulocytes Isolated from Patients with Asthma

Background: The effect of aspirin on the release of key arachidonic acid metabolites in activated eosinophils from subjects with aspirin-intolerant asthma (AIA) has not been investigated previously, despite the characteristic eosinophilia in AIA. Methods: Peripheral blood eosinophils were isolated from four groups of subjects: healthy volunteers (HV; n = 8), mild asthma (MA; n = 8), severe asthma (SA; n = 9) and AIA (n = 7). In the absence or presence of lysine-aspirin, eosinophils were stimulated with arachidonic acid or calcium ionophore to trigger the 15-lipoxygenase-1 (15-LO) and 5-lipoxygenase (5-LO) pathways, respectively. 15(S)-hydroxy-eicosatetraenoic acid (15-HETE) and eoxin C₄ (EXC₄) were measured as 15-LO products and leukotriene (LT)C₄ as a product of the 5-LO pathway. Results: Activated eosinophils from patients with SA and AIA produced approximately five times more 15-HETE than eosinophils from HV or MA patients. In the presence of lysine-aspirin, eosinophils from AIA, MA and SA patients generated higher levels of 15-HETE than in the absence of lysine-aspirin. Furthermore, in the presence of lysine-aspirin, formation of EXC₄ was also significantly increased in eosinophils from AIA patients, and LTC₄ synthesis was increased both in AIA and SA patients. Conclusions: Taken together, this study shows an increased release of the recently discovered lipid mediator EXC₄, as well as the main indicator of 15-LO activity, 15-HETE, in activated eosinophils from severe and aspirin-intolerant asthmatics, and also elevated EXC₄ and LTC₄ formation in eosinophils from AIA patients after cellular activation in the presence of lysine-aspirin. The findings support a pathophysiological role of the 15-LO pathway in SA and AIA.

Strategy for NSAID administration to aspirin-intolerant asthmatics in combination with PGE2 analogue: a theoretical approach

Aspirin-induced asthma (AIA) is a severe inflammatory disease, which affects aspirin-intolerant patients after ingestion of aspirin or other non-steroidal anti-inflammatory drugs (NSAIDs). In this article, a mathematical model describing arachidonic acid metabolism and its interaction with NSAIDs, is used to study the strategy for safe managing of NSAIDs to AIA patients. Three different AIA patient populations are taken into consideration. First, the values of aspirin and ibuprofen limiting doses that might induce symptoms of AIA are calculated and compared to experimentally observed threshold doses to enlighten which AIA patient population is susceptible to aspirin and ibuprofen. Second, the methodology of NSAID administration is studied on AIA populations susceptible to aspirin and ibuprofen by using 1,000 mg dose of aspirin and 200 or 400 mg dose of ibuprofen followed by PGE(2) analogue dosing. Our model results show that successive doses of PGE(2) analogue applied at appropriate time after aspirin or ibuprofen ingestion would enable administration of both NSAIDs to AIA patients. PGE(2) analogue doses and the corresponding times of their applications are calculated. The model is also used to estimate the duration of symptoms of AIA for different aspirin and ibuprofen doses.

Epigenetic changes in B lymphocytes associated with house dust mite allergic asthma

Although there is no doubt about the influence of the genetic background in the onset of the allergic diseases, Epigenome-Wide Association Studies are needed to elucidate the possible relationship between allergic diseases and epigenomic dysregulation. In this study we aimed to analyze the epigenetic patterns, in terms of DNA methylation, of three well-characterized populations of house dust mite allergic subjects, aspirin-intolerant asthmatics and controls. As a first, genome-wide phase, we used the HELP assay to study the methylation patterns in CD19+ B lymphocytes in these populations, and found that there are reproducible epigenetic differences at limited numbers of loci distinguishing the groups, corroborated by bisulphite MassArray in a second validation phase of an expanded 40 subject group. These validated epigenetic changes occur at loci characterized as important for the immune response. One such locus is a new candidate gene, CYP26A1, which shows differential methylation patterns and expression levels between groups. Our results suggest that epigenomic dysregulation may contribute to the susceptibility to allergic diseases, showing for the first time differences in DNA methylation between allergic and non-allergic healthy subjects, both globally and at specific loci. These observations indicate that the epigenome may offer new pathophysiological insights and therapeutic targets in atopic diseases.

Mediators of inflammation in nasal lavage from aspirin intolerant patients after aspirin challenge

The pathogenetic mechanisms underlying development of persistent inflammation in aspirin (ASA) intolerance are not fully understood. The aim of this study was to determine levels of MCP-3, RANTES, eotaxin, Il-5 and Il-3 in aspirin intolerant asthmatics (AIA) after nasal lysine-aspirin (Lys-ASA) challenge. Twenty AIA and 10 aspirin tolerant controls (ATC) were challenged with saline or 14.4mg of Lys-ASA. Lys-ASA challenge induced clinical symptoms and influx of eosinophils and basophils only in AIA group. Statistically significant higher levels of MCP-3 and RANTES were found in lavages from AIA as compared with ATC (p<0.05 in all time points). Before challenge the average level of MCP-3 was 86.95pg/ml in AIA and 47.61pg/ml in ATC, RANTES levels were 34.20pg/ml in AIA and 17.21pg/ml in ATC and did not change after the challenge in both group. The mean eotaxin's level was 11.01pg/ml in AIA and 8.03pg/ml in ATC before and increased to 20.06, 26.22pg/ml (4 and 24h in AIA) as compared to 10.51, 14.76pg/ml (4 and 24h in ATC) after the challenge (p<0.05). Interleukin-3 and Il-5 were not detectable. The highest inhibition of eosinophils' chemotaxis was induced by anti-eotaxin (47% of inhibition), followed by anti-RANTES (29%), anti-MCP-3 (19%) and anti-Il-5 (9%). In summary, we found that persistent inflammation in AIA patients is characterized by overproduction of MCP-3 and RANTES. Lack of increase in MCP-3 and RANTES levels after Lys-ASA challenge suggest that those mediators are involved in chronic rather than acute phase of ASA induced inflammation.

Association of angiotensin I‐converting enzyme gene polymorphisms with aspirin intolerance in asthmatics

Aspirin-intolerant asthma (AIA) refers to the development of bronchoconstriction in asthmatic individuals following the ingestion of aspirin or other non-steroidal anti-inflammatory drugs (NSAIDs). Angiotensin I-converting enzyme (ACE), a membrane-bound peptidase present in the lung, plays a pivotal role in the metabolism of the endogenous peptides involved in the pathogenesis of asthma. We screened a Korean asthma cohort (581 asthmatics including 81 aspirin-intolerant asthmatics and 231 aspirin-tolerant asthmatics, and 181 normal controls) for four single nucleotide polymorphisms (SNPs; -262 A>T and -115 T>C in the 5'-flanking region and +5467 T>C [Pro450Pro] and+11860 A>G [Thr776Thr] in the coding region) and one ins/del (+21288 CT) in the ACE gene. None of the SNPs or haplotypes showed any association with the development of asthma, but they were significantly associated with the risk of AIA. Logistic regression indicated that the frequency of the rare alleles of -262 A>T and -115 T>C was higher in subjects with AIA than in subjects with aspirin-tolerant asthma (ATA) (P=0.003-0.01, P( corr)=0.015-0.05). Subjects homozygous for the rare alleles of -262 A>T and -115 T>C showed a greater decline in forced expiratory volume in 1 s (FEV(1)) after aspirin provocation than those homozygous for the common alleles (P<0.05). A luciferase reporter assay indicated that ACE promoters containing the rare -262 A>T allele possessed lower activity than did those containing the common allele (P=0.009). In addition, ACE promoters bearing the rare -115 T>C allele had no luciferase activity. DNA-protein binding assays revealed a band containing the ACE promoter region (including -262 A) and a protein complex. The -262 A>T polymorphism in the promoter of the ACE gene is associated with AIA, and the rare allele of -262 A>T may confer aspirin hypersensitivity via the down-regulation of ACE expression.

Corticosteroid therapy increases membrane‐tethered while decreases secreted mucin expression in nasal polyps

Mucus hypersecretion is a hallmark of nasal polyposis (NP). Corticosteroids (CS) are first-line treatment for NP, decreasing their size and inflammatory component. However, their effect on mucin production is not well-understood. The aim of this (pilot) study was to investigate CS effect on mucin expression in NP. Patients were randomized in control (n = 9) and treatment (oral prednisone for 2 weeks and intranasal budesonide for 12 weeks; n = 23) groups. Nasal polyposis from nonasthmatic (NP; n = 13), aspirin-tolerant (NP-ATA; n = 11) and aspirin-intolerant (NP-AIA; n = 8) asthmatics were studied. Nasal polyposis biopsies were obtained before (w0) and after 2 (w2) and 12 (w12) weeks of CS treatment. Secreted (MUC5AC, MUC5B and MUC8) and membrane-tethered (MUC1, MUC4) mucins (immunohistochemistry) and goblet cells (Alcian blue-periodic acid Schiff) were quantified in both epithelium and glands. Rhinorrea and nasal obstruction were also assessed. At w2, steroids increased MUC1 (from 70 to 97.5) and MUC4 (from 80 to 100) in NP-ATA patients' epithelium compared with baseline (w0). At w12, steroids decreased MUC5AC (from 40 to 5) and MUC5B (from 45 to 2.5) in NP-ATA patients' epithelium and glands, respectively, compared with baseline. No mucin presented significant changes in NP-AIA patients. MUC5AC and MUC5B expression correlated with goblet and mucous cell numbers, respectively, and MUC5AC also with rhinorrea score. These results suggest: (i) CS up-regulate membrane (MUC1, MUC4) while down-regulate secreted (MUC5AC, MUC5B) mucins; (ii) there exists a link between secreted mucin expression and goblet cell hyperplasia; and (iii) NP from AIA may develop resistance to CS treatment.

Cysteinyl-Leukotrienes in Cerebrovascular Disease

Although the initial interest in the field of leukotriene (LT) research was focused on their potent bronchoconstrictive effects, subsequent studies have suggested LTs as key mediators in several inflammatory diseases. Genetic variations within the enzymes transforming arachidonic acid into LTs (Figure) have for example been associated with atherosclerosis and an increased risk of cardiovascular events.1 Figure Metabolism of arachidonic acid into leukotrienes (LTs) by 5-lipoxygenase (5-LO), 5-LO activating protein (FLAP), LTA4 hydrolase (LTA4H), and LTC4 synthase (LTC4S). Cysteinyl-LTs (LTC4, LTD4, LTE4) activate CysLT receptors, which can be targeted by antiasthmatic CysLT1 receptor antagonists. Inset shows the 5 exons (I-V) of the LTC4S gene and its 5′-flanking untranscribed region (UTR). The 2 reported single nucleotide polymorphisms (SNP) are located at 444 and 1072 bp upstream, respectively. The −444 A to C substitution has been associated with increased LTC4 synthesis in eosinophils,6 aspirin intolerant asthma,5 increased risk for coronary calcium,10 increased carotid artery intima media thickness (IMT),10 and a decreased risk of ischemic cerebrovascular events.4 See accompanying article on page 990 Leukotriene C4 synthase (LTC4S; Figure) is a microsomal glutathione-S-transferase (mGST), which conjugates LTA4 with glutathione.2 The product, LTC4, shares its following enzymatic steps with glutathione to …

The human leucocyte antigen‐DRB1*1302‐DQB1*0609‐DPB1*0201 haplotype may be a strong genetic marker for aspirin‐induced urticaria

Urticaria/angioedema is a common aspirin-induced allergy; however, its pathogenic mechanism is not understood. In order to uncover the genetic mechanism, we studied the associations of the human leucocyte antigen (HLA) genotypes in patients with aspirin-induced urticaria compared with aspirin-intolerant asthma and normal control in a Korean population. Ninety-four aspirin-induced urticaria patients presenting urticaria/angioedema-induced by both ASA and NSAID (50 had underlying chronic urticaria) and showing positive responses on oral aspirin challenge test, 76 aspirin-intolerant asthmatics with positive responses on lysine-aspirin bronchoprovocation test, and 185 normal healthy controls were enrolled. HLA-DRB1, DQB1, and DPB1 genotypings were performed by direct DNA sequencing analysis. The allele frequencies of HLA-DRB1(*)1302 (18.1%) and HLA-DQB1(*)0609 (10.1%) in aspirin-induced urticaria were significantly higher than in aspirin-intolerant asthma (5.3%, P=0.0004; 2.0%, P=0.0024) and in normal controls (8.1%, P=0.0005; 3.2%, P=0.0008), and they remained significant after correcting for multiple comparisons. The patients with these two HLA markers had a significantly younger age than patients without, while no associations were found in with respect to atopic status, a history of previous allergic diseases, total IgE level, or presence of underlying chronic urticaria (P>0.05, respectively). In haplotype analysis, the HLA-DRB1(*)1302-DQB1(*)0609-DPB1(*)0201 was significantly higher in the aspirin-induced urticaria (8.0%) than in the aspirin-intolerant asthma (0.7%, P=0.0014) and normal controls (2.0%, P=0.0006). These findings suggest that the HLA-DRB1(*)1302-DQB1(*)0609-DPB1(*)0201 may be a strong genetic marker to determine the aspirin-induced urticaria phenotype.

Prospective clinical study of the expression of the cox-2 gene in nasal polyposis

Problem: Nasosinusal polyposis (NP) is an inflammatory disease, with higher incidence in asthmatic patients than nonasthmatic, especially in aspirin-intolerant asthmatics. Corticoids are the first line of treatment of NP. The research objective was to demonstrate the existence of different degrees of inflammation in the NP associated or not with asthma, and its different response to corticoid treatment. Methods: Our sample consisted of 80 patients with NP, 19 of whom were assigned to the control group and 61 to the experimental group. Of the latter group, 22 did not have asthma (NPNA), 21 had tolerable asthma (NP+TA), and 18 had intolerant asthma to acetylsalicylic acid (PN+IA). We performed a clinical evaluation (subjective nasal obstruction, nasal endoscopy, rhinomanometry, and computerized tomography) and experimental evaluation (expression of the Cox-1 and Cox-2 gene) after 4 weeks without corticoid treatment (baseline), after 2 weeks of treatment with oral corticoids (OCC), and 12 weeks of intranasal corticoids (ICC). Results: At week 2 there are significant differences between the study and control groups ( P < 0.001). After treatment with OCC, patients with NP improve clinically and significantly increase the expression of the Cox-2 gene ( P < 0.01). The ICC maintain the clinical improvement ( P < 0.01) but not the increased expression of the Cox-2 gene. The expression of Cox-1 does not present variations, not even after treatment with OCC or ICC. The endoscopic evaluations are correlated with the tomographic grade before (r = 0.51; P < 0.01) and after the treatment (r = 0.6; P < 0.01). Conclusion: We conclude from these results that OCC and ICC are effective with all patients, but to a lesser extent when associated with tolerant or intolerant asthma to acetylsalicylic. Also, nasal endoscopy is at least as useful a technique as the computerized tomography for the follow-up of NP. Significance: The expression of Cox-2 gene changes in patients with NP under OCC treatment but not under ICC. Support: Grant from the Ministry of Health FIS 99–0133. 1999–2001. Project: Nasal poliposi and inflammation.

Metamizole intolerance and bronchial asthma

Metamizole is one of the pyrazolone drugs used widely in Turkey. The aim of this survey was to determine the clinical features of metamizole intolerant patients and to find out if there was any difference between the ones with or without bronchial asthma. A total of 264 patients with metamizole intolerance were enrolled in the survey. Patients having bronchial asthma were accepted as group I (n = 133) and the ones without bronchial asthma as group II (n = 131). A standard questionnaire was used to collect the data. The mean age of the patients were 41.8 11.8 and 39.2 12.2 for groups I and II respectively and 99 (79.4 %) and 99 (75.6 %) were females in the same order. There was no significant difference between groups I and II when the rates of personal atopy, familial atopy and familial analgesic intolerance were compared. The most common reactions appearing after metamizole ingestion was bronchospasm (75.9 and 9 %) and urticaria (25.6 and 64.9 %) (for groups I and II, respectively and p < 0.05). Aspirin cross-reactivity was significantly more common in group I. At least one safe alternative analgesic was determined for all the patients who have not been able to use any analgesic. Metamizole intolerance seems to be as important as aspirin intolerance in Turkey. The clinical features in general appear to be similar for metamizole and aspirin intolerant asthmatics.

A moderate and unspecific release of cysteinyl leukotrienes by aspirin from peripheral blood leucocytes precludes its value for aspirin sensitivity testing in asthma.

Aspirin-induced asthma (AIA) is a clinical syndrome related to cysteinyl leukotriene overproduction in airways. The confirmation of the diagnosis requires inconvenient provocation tests with acetyl salicylic acid (ASA). A study was performed to evaluate whether measurement in vitro of cysteinyl leukotrienes (cys-LTs) release by isolated peripheral blood leucocytes, stimulated with ASA, can be of use for diagnosis of AIA. A cellular allergen stimulation test, CAST, was adapted to measure leukotriene release from leucocytes of 32 aspirin-tolerant and 26 aspirin-intolerant asthmatics. The cells were stimulated with Lys-ASA, N-formyl-methionyl-leucyl-phenylalanine (fMLP), or both fMLP and Lys-ASA, in a buffer containing IL-3, and results compared with human leukaemia cell line (Hl-60) response to Lys-ASA. Cys-LTs were measured in cell supernatant fluids by ELISA. ASA had a rather week stimulatory effect on cys-LTs release in both groups of patients. Contrary to some previous studies, no significant differences were found between cys-LTs release by leucocytes from AIA and ATA, or by differentiated Hl-60 cells. Measurement of cysteinyl-leukotriene release by peripheral blood leucocytes pre-treated with aspirin has no value for diagnosis of AIA.

Aspirin-tolerant asthmatics generate more lipoxins than aspirin-intolerant asthmatics.

Asthma is characterized by chronic airway inflammation resulting from overproduction of pro-inflammatory mediators, such as leukotrienes (LT). The authors questioned the biosynthetic capacity of asthmatic patients for lipoxins (LX) and 15-epimer lipoxins (15-epi-LX), endogenous regulators of inflammatory responses that inhibit pro-inflammatory events. Levels of LXA4, 15-epi-LXA4 and LTC4 were determined in 14 clinically characterized aspirin-intolerant asthmatics (AIA), 11 aspirin-tolerant asthmatics (ATA) and eight healthy volunteers using a stimulated whole blood protocol. Both LXA4 and 15-epi-LXA4 were generated in whole blood activated by the divalent cation ionophore, A23187. Higher levels of LXA4 were produced in ATA than either AIA or healthy volunteers. Exposure of AIA whole blood to interleukin-3 prior to A23187 did not elevate their reduced capacity to generate LXA4. Generation of a bronchoconstrictor, LTC4, was similar in both AIA and ATA. Consequently, the ratio of LXA4:LTC4 quantitatively favoured the bronchoconstrictor for AIA and differed from both ATA and healthy subjects. In addition, the capacity for 15-epi-LXA4 generation was also diminished in AIA, since whole blood stimulated in the presence of aspirin gave increased levels only in samples from ATA. The present results indicate that asthmatics possess the capacity to generate both lipoxins and 15-epimer-lipoxins, but aspirin-intolerant asthmatics display a lower biosynthetic capacity than aspirin-tolerant asthmatics for these potentially protective lipid mediators. This previously unappreciated, diminished capacity for lipoxin formation by aspirin-intolerant asthmatic patients may contribute to their more severe clinical phenotype, and represents a novel paradigm for the development of chronic inflammatory disorders.

Treatment of aspirin-intolerant asthma with antileukotrienes.

Intolerance to aspirin and related nonsteroidal antiinflammatory drugs (NSAIDs) is a significant clinical problem among subjects with asthma (reviewed in References 1 and 2). Aspirin-intolerant asthmatics often suffer from a particularly severe form of asthma (2). Characteristically, in adult life the subjects develop chronic rhinosinusitis and recurrent polyposis, asthma, and intolerance to aspirin-like drugs. Ingestion of NSAIDs precipitates acute bronchoconstriction, which is often severe and persistent. Extrapulmonary symptoms such as nasal congestion, ocular injection, flush, heat rash, perspiration, and occasionally gastrointestinal symptoms may accompany the airway obstruction, in isolation or in combination. In severe cases the reaction can progress into shock and respiratory arrest. While there are no in vitro tests available for routine clinical diagnosis, the lysine-aspirin bronchoprovocation introduced by Bianco and coworkers (3), has proven useful in identifying aspirin-intolerant patients with asthma. In a prospective comparative study the lysine-aspirin bronchoprovocation was found to be as sensitive as the oral provocation with respect to detection of airway obstruction (4). In that study, 22 consecutive patients with a history and/or clinical findings (asthma, rhinorrhea, nasal polyposis) suggestive of aspirin intolerance were challenged by both routes at least 2 wk apart. Ten of the subjects developed significant bronchoconstriction (≥ 20% drop in forced expiratory volume in 1 s [FEV 1 ]) during either challenge, with the same absolute sensitivity for both tests (9 of 10). The bronchial provocations evoked reactions that developed more promptly, were limited to the airways, caused a lesser degree of airway obstruction, and were more easily reversed. The differences in challenge methods are summarized in Table 1. In 19 aspirin-tolerant control subjects with the same baseline pulmonary function, inhalation of lysine-aspirin caused no significant changes in FEV 1 , supporting the specificity of the test. Although the oral administration is necessary for detection and investigation of extrapulmonary reactions, the bronchial challenge has characteristics supporting it as the first choice both in routine clinical practice and in mechanistic investigations. For the latter purpose, safety aspects and high repeatability (5) provide a considerable advantage over the oral challenge, particularly because a significant proportion of aspirin-intolerant individuals with asthma suffer from severe asthma. The time course of an inhalation challenge with lysine-aspirin is exemplified in Figure 1. It is well established that cyclooxygenase inhibition is central in the chain of events leading to aspirin-elicited reactions (1). Plasma concentrations of acetylsalicylic acid (ASA), measured at the time of reaction following oral provocations, are of the magnitude (3-30 μM) (6) that has been established to inhibit cyclooxygenases in various test systems (7). Salicylic acid (SA), the main metabolite of ASA, is found at much higher concentrations (20-250 μM) (6). However, SA is not responsible for the intolerance reactions, because provocations with sodium salicylate with commonly used doses (0.5-1.0 g) yield much higher plasma concentrations of SA that are tolerated by NSAID-sensitive individuals (6).

Arachidonic Acid Metabolism in Nasal Tissue and Peripheral Blood Cells in Aspirin Intolerant Asthmatics

Aspirin intolerance (AI) is characterized by polypous rhinosinusitis, bronchial asthma and adverse reactions to aspirin. The common intolerance to all cyclo-oxygenase inhibitors allows us to focus study of the pathogenesis of AI on the metabolism of arachidonic acid (AA). We studied the metabolism of AA in nine aspirin intolerant asthmatics (AIA) and eight healthy volunteers (controls) by measuring prostaglandin E2 (PGE2) and peptido-leukotrienes (pLT=LTC4/D4/E4) in nasal tissue and peripheral blood cells (PBCs) using a specific immunoassay. In all patients with AI the tests were performed before and after bronchial provocation with lysine-ASA. In the control group the tests were done before and after 500 mg ASA p.o. The release of pLT in nasal polyps of AIA was found to be significantly higher than in normal mucosa of AIAs and controls. In every tissue a significant increase of pLT after aspirin challenge was observed. Nasal polyps of AIA show a significantly lower release of PGE2 than normal mucosa of AIAs and controls. Peripheral blood cells of AIA show a significantly higher release of pLT and a significantly lower release of PGE2 than PBCs of controls. Therefore clinical manifestations of AI may be based on an alteration of AA metabolism in AIA.

Lipid mediator pathways in the lung: leukotrienes as a new target for the treatment of asthma.

This article summarizes recent evidence supporting that antileukotriene drugs represent a new treatment of asthma which may be particularly effective when combined with drugs that have complementary effects on airway obstruction and inflammation. Firstly, it has been documented that glucocorticosteroids do not inhibit in vivo production of leukotrienes in asthmatics. In line with such findings, addition of antileukotriene drugs to a group of aspirin-intolerant asthmatics maintained on conventional therapy was found to result in an improvement of the asthma over and above the effect of the baseline treatment with inhaled and/or oral glucocorticosteroids. Likewise, in a 6-week trial in a group of severe asthmatics, the asthma deterioration caused by a reduction of the dose of inhaled steroids by half, was prevented by addition of a leukotriene antagonist to the lowered dose of glucocorticosteroids. Current evidence therefore supports that antileukotriene drugs treat components of the pathophysiology which are left unaffected by treatment with glucocorticosteroid. Secondly, in experimental studies as well as in a recent allergen bronchoprovocation study in asthmatics, it has been found that the combination of antihistaminics with antileukotriene drugs will result in a profound inhibition of both the early and the late phase of allergen-induced airway obstruction. It is hypothesized that such a combination may be useful against bronchoconstriction induced by other asthma trigger factors as well as in the treatment of asthma and rhinitits.

541 RANTES levels and eosinophils increase in broncoalveolar lavage fluid (BALF) after indomethacin in aspirin-intolerant asthmatics (AIA)

541 RANTES levels and eosinophils increase in broncoalveolar lavage fluid (BALF) after indomethacin in aspirin-intolerant asthmatics (AIA)

The leukotriene-receptor antagonist MK-0679 blocks airway obstruction induced by inhaled lysine-aspirin in aspirin-sensitive asthmatics

Drugs which block the action or formation of the cysteinyl leukotrienes (LTC4, LTD4 and LTE4) inhibit asthmatic responses evoked by allergen, exercise and cold dry air. The purpose of this study was to determine whether the specific leukotriene-receptor antagonist MK-0679 could block the airway obstruction induced by aspirin (acetylsalicylic acid (ASA)) in aspirin-intolerant asthmatics. Eight asthmatics (mean age 45 yrs), with an average history of asthma and ASA-sensitivity of about 10 yrs duration, were subjected to bronchial provocation with lysine-ASA. Baseline ASA-sensitivity was first determined in an open prestudy session by inhalation of cumulative doses of lysine-ASA to establish the dose of ASA decreasing forced expiratory volume in one second (FEV1) by 20% (PD20). Rechallenge with lysine-ASA was performed on two different occasions, 1 h after oral administration of placebo, or 750 mg of MK-0679, under double-blind conditions, in a randomized, cross-over design. Leukotriene formation was estimated by the measurement of urinary LTE4. The lysine-ASA challenge was highly reproducible (geometric mean for group PD20 being identical for the open prestudy and the placebo session), and was associated with a post-challenge increase in urinary LTE4. In contrast, after MK-0679, there was a rightward shift in the dose response relationship for all eight subjects (median shift being 4.4 fold), with three of the subjects failing to produce a 20% decrease in FEV1 despite inhalation of the highest dose of lysine-ASA feasible to deliver.(ABSTRACT TRUNCATED AT 250 WORDS)

Aspirin-sensitive asthma: abnormal platelet response to drugs inducing asthmatic attacks. Diagnostic and physiopathological implications.

The pathogenesis of aspirin-sensitive asthma remains unknown. Using a new model of platelet activation, initially described as a response of platelets to IgE antibody-dependent stimuli, this study was designed to test the hypothesis of a possible involvement of platelets in aspirin-sensitive asthma. Washed platelets from 35 aspirin-sensitive asthmatics showed an abnormal in vitro response to cyclooxygenase inhibiting nonsteroidal anti-inflammatory drugs (NSAIDs)--aspirin, indomethacin or flurbiprofen--characterized by the generation of a cytocidal supernatant and (14 patients explored) a burst of chemiluminescence; these drugs had no similar effect on platelets from 31 controls (p less than 0.0001). It was shown that the abnormal platelet response to NSAIDs was not mediated by IgE. In contrast to platelets, aspirin-sensitive asthmatic leukocytes generated neither cytocidal factors nor chemiluminescence in the presence of NSAIDs. Sodium salicylate and salicylamide, which, though structurally similar to aspirin, do not inhibit cyclooxygenase and are well tolerated by aspirin-sensitive asthmatics, did not activate their platelets to release cytocidal factors. Moreover, preincubation of platelets with sodium salicylate, salicylamide or prostaglandin endoperoxide PGH2, highly prevented their abnormal response to NSAIDs (greater than 80%; p less than 0.0001). Since several lipoxygenase inhibitors (NDGA, esculetin), including inhibitors of both cyclooxygenase and lipoxygenase (ETYA, BW755c), did not activate patient platelets and prevented the subsequent abnormal response to NSAIDs, it is suggested that the abnormal platelet activation by NSAIDs is not only the consequence of an inhibition of cyclooxygenase, but also involves generation of lipoxygenase metabolites of arachidonate. Besides, platelets from 4 aspirin-sensitive asthmatics undergoing aspirin desensitization were found to have completely lost their abnormal responsiveness to NSAIDs. These findings represent the first identification in aspirin-intolerant asthmatics of a specific abnormal cellular response to drugs inducing asthmatic attacks and open new perspectives into the pathogenesis, prevention and diagnosis of this disease. They also provide support to the concept of a role for platelets in asthma.

Oral aspirin challenges in asthmatic patients: a study of plasma histamine.

Under carefully controlled conditions, seven aspirin-intolerant asthmatic patients were challenged with oral aspirin and experienced respiratory tract reactions with a decline in forced expiratory volume in 1 sec (FEV1) ranging from 26 to 64%. Venous blood samples, which were collected during the challenges, showed a rise in plasma histamine in all seven patients. The increase in plasma histamine occurred at the onset of their respiratory reactions and those patients with the most severe asthmatic responses were found to have the highest and most prolonged levels of plasma histamine. The aspirin-intolerant asthmatic patients were able to ingest Maalox or sodium salicylate without untoward effects, decline in FEV1 values or changes in plasma histamine levels. Ten non-asthmatic individuals and eight out of ten asthmatic control patients were able to ingest aspirin without any reactions or changes in their plasma histamine levels. However, two asthmatic control individuals, with severe asthma requiring treatment with moderate dosages of corticosteroids, were found to have elevated pre-challenge plasma histamine levels which increased during their ASA challenges despite the absence of respiratory reactions or changes in FEV1 values. It is possible that these two individuals were unsuspected aspirin-intolerant asthmatics. These studies demonstrate that asthmatic reactions to acetylsalicylates are associated with release of histamine into plasma in the subgroup of asthmatic patients with the aspirin-intolerance syndrome. Such a finding suggests that histamine may be one of the mediators of bronchospasm in aspirin-induced asthma.