Some patients with severe asthma cannot be controlled with high doses of inhaled steroids (ICS), which may be related to ongoing environmental allergen exposure. We investigated whether 10 weeks of high altitude allergen avoidance leads to sustained benefits regarding clinical and inflammatory markers of disease control in adolescents with persistent asthma despite treatment with high dose ICS. Eighteen atopic asthmatic adolescents (12–18 yr, 500–2000 µg ICS daily) with established house dust mite allergy, participated in a parallel‐group study. Quality of life (PAQL), lung function, bronchial hyperresponsiveness (BHR) to adenosine and histamine, induced sputum and urine samples were collected repeatedly from 10 patients during a 10‐week admission period to the Swiss Alps (alt. 1560 m) and at 6 weeks after return to sea level. Results were compared with those in eight patients, studied in their home environment at sea level for a similar time period. Throughout the study, asthma medication remained unchanged in both groups. During admission to high altitude, PAQL, lung function, BHR to adenosine and histamine, and urinary levels of eosinophil protein X (U‐EPX), leukotriene E4 (U‐LTE4) and 9α11β prostaglandin F2 (U‐9α11β PGF2) improved significantly (P < 0.05), with a similar tendency for sputum eosinophils (P < 0.07). Furthermore, the changes in PAQL and BHR to adenosine and histamine were greater in the altitude than in the control group (P < 0.05). At 6 weeks after renewed allergen exposure at sea level, the improvements in PAQL (P < 0.05), BHR to adenosine (P < 0.07) and histamine (P < 0.05), as well as U‐EPX (P < 0.05) and U‐LTE4 (P < 0.05) were maintained. A short period of high altitude allergen avoidance, on top of regular treatment with ICS and long‐acting β2‐agonists, results in improvement of asthma, as assessed by clinical and inflammatory markers of disease severity. These findings indicate that short‐term, rigorous allergen avoidance can improve the long‐term control of severe asthma over and above what can be achieved even by high doses of inhaled steroids.

Abstract. Claesson H-E, Dahlén S-E (Karolinska

These results indicate that mast cell activation is a feature not only of the early but also the late asthmatic response. Finally, increased LTE4 supports the contribution of the leukotrienes to airway obstruction during both phases of the asthmatic response to allergen.

Exercise-induced bronchoconstriction (EIB) is thought to occur in 70-80% of asthmatics, most commonly amongst those with moderate-to-severe airway hyperresponsiveness [1]. It is characterized by transient airflow obstruction resulting in a Š15% decrease in forced expiratory volume in one second (FEV1) following 5-8 min of exercise. The fall in FEV1 reaches a maximum approximately 10 min after exercise and gradually normalizes over the next hour [2]. The precise pathophysiology of EIB remains unclear, although it is widely accepted that during exercise the upper airways are unable to adequately warm and humidify the increased volumes of inspired air. This results in airway cooling and increased airway fluid osmolality in the lower airways [3,4]. One hypothesis suggests that hyperosmolar triggering of mast cells and possibly other inflammatory cells results in the release of bronchoconstricting mediators, e.g. cysteinyl-leukotrienes (cys-LTs), histamine and prostaglandin (PG)D 2 [5].Previous indications for the participation of mast cell mediators in the pathogenesis of EIB are based on pharmacological data. For example, disodium cromoglycate (DSCG), a drug which stabilizes mast cell membranes, is effective in blunting exercise-induced asthma [6,7]. Pretreatment with a number of H 1 receptor antagonists has been shown to attenuate EIB [8][9][10]; however, the degree of protection afforded by this class of drugs has been modest. More recently, studies employing leukotriene receptor antagonists [11,12] and biosynthesis inhibitors [13] have implicated leukotrienes in the airway bronchoconstrictor response to exercise.The direct approach of measuring mast cell mediator release in response to exercise challenge has yielded ambiguous results. Some studies have reported an elevation in plasma and whole blood histamine concentrations following EIB [14,15], while other studies have failed to verify those findings [16,17]. Apart from the methodological problems encountered when sampling plasma histamine [18] and its short half-life in the circulation, approximately 1 min [19], it has been suggested that elevations in plasma histamine mainly reflect the basophilia which normally accompanies exercise [20]. Increases in the levels of tryptase and PGD 2 , both specific mast cell markers, have been detected in nasal lavage following nasal provocation with cold dry air [21], but not after exercise [22,23].The purpose of this study was to provide evidence to establish mast cell activation as a feature of EIB. To this end, a combination of mast cell markers, 9α,11β-PGF 2 Sullivan, A. Roquet, B. Dahlén, F. Larsen, A. Eklund, M. Kumlin, P.M. O'Byrne, S-E. Dahlén. ©ERS Journals 1998. ABSTRACT: Controversy remains about the causative mediators in the bronchoconstrictive response to exercise in asthma. This study examined whether mast cell activation is a feature of exercise-induced bronchoconstriction by measuring urinary metabolites of mast cell mediators. Evidence for mast cell activation during exercise-induced bronchoconstriction....

No abstract

Expression of mRNA for EP receptors and key enzymes in the PGE2 pathway were assessed by real-time PCR using species-specific primers. Functional studies of GPT were performed in tissue organ baths. KEY RESULTSExpression of mRNA for the four EP receptors was found in airway smooth muscle. PGE2 displayed a bell-shaped concentration-response curve, where the initial contraction was inhibited by the EP1 receptor antagonist ONO-8130 and the subsequent relaxation by the EP2 receptor antagonist PF-04418948. Neither EP3 (ONO-AE5-599) nor EP4 (ONO-AE3-208) selective receptor antagonists affected the response to PGE2. Expression of COX-2 was greater than COX-1 in GPT, and the spontaneous tone was most effectively abolished by selective COX-2 inhibitors. Furthermore, ONO-8130 and a specific PGE2 antibody eliminated the spontaneous tone, whereas the EP2 antagonist PF-04418948 increased it. Antagonists of other prostanoid receptors had no effect on basal tension. The relaxant EP2 response to PGE2 was maintained after long-term culture, whereas the contractile EP1 response showed homologous desensitization to PGE2, which was prevented by COX-inhibitors.

Background and purpose: The pharmacological properties of compounds NCX 1512 and NCX 1514, synthesized by linking the histamine H1-receptor antagonist cetirizine to NO-releasing spacer groups, are reported. The aim was to establish if the compounds retained the antihistamine action of the parent compound, to assess their efficacy as NO donors and to test if they had broader antiallergic activity than cetirizine in the lung. Experimental approach: Antihistamine activity of NCX 1512 and NCX 1514 was investigated in vitro in the guinea pig ileum, in tracheal rings (GPTR) and lung parenchymal strips (GPLP) of the guinea-pig. The NO-releasing capacity was investigated in vascular preparations; the isolated rabbit and guinea-pig aorta and guinea-pig pulmonary artery. Kinetics of NO release were assessed in a rat whole blood assay. Key results: Both NCX 1512 and NCX 1514 retained activity as H1-receptor antagonists in the guinea pig ileum and airway preparations. The NO-releasing NCX compounds relaxed the rabbit aorta, an action prevented by the guanylyl cyclase inhibitor ODQ (10 mM). NCX 1512 and NCX 1514 did not relax the antigen (ovalbumin) pre-contracted GPTR, whereas the NO donors NCX 2057 and DEA-NONOate relaxed guinea-pig pre-contracted vascular and tracheal preparations. Cetirizine (1-100 mM) and NCX 1512 (1-100 mM) reduced the cumulative (0.01-100 mg ml À1 ) ovalbumin-induced constriction in GPTR, but had no significant effect in GPLP. Conclusions and implications: NCX 1512 and NCX 1514 act as antihistamines and NO donors. However, there was no improved effect compared to cetirizine on antigen-induced constriction of the central and peripheral lung. (2007) British Journal of Pharmacology

Summary The cysteinyl leukotrienes (CysLTs) induce a number of pro‐inflammatory effects including smooth muscle contraction, an increase in blood flow, plasma exudation, mucous secretion, and activation of inflammatory cells. They play a key role in asthma and allergy, and can be recovered from different body fluids (e.g. bronchoaleveolar or nasal lavage and urine) during allergen‐induced hypersensitivity reactions. The advent of antileukotriene agents (i.e. leukotriene receptor antagonists or leukotriene synthesis inhibitors) has helped clarify how the different mechanisms contribute to inflammation, as well as offer new treatment options for both asthma and allergy. It is now clear that the release of leukotrienes is the final common path for the many different factors causing airway obstruction and inflammation. In asthma, clinical studies have shown that treatment with antileukotrienes can improve pulmonary function, alleviate symptoms, reduce asthma exacerbations, and decrease the need for bronchodilator therapy. Similarly, in patients with allergic rhinitis, improvements have been seen in nasal symptoms, eye symptoms and quality of life. Antileukotrienes provide a new opportunity for simultaneous management of allergic diseases of the upper and lower respiratory tract, and are a rational treatment approach to the concept of ‘one airway’ disease. In future, their utility may also extend to inflammatory disorders of other organ systems (e.g. skin).