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Nuove acquisizioni sul meccanismo di azione dei corticosteroidi.
In: Allergologia e immunologia clinica: dalla biologia alla clinica. Dammacco F., Ferrannini A., Tursi A., Eds. Monduzzi Editore, Bologna
EFFETTI DEL MONTELUKAST SULLA BIOSINTESI DEI LEUCOTRIENI E SULL'ATTIVITA' ENZIMATICA DELLA 5-LO
Benralizumab improves patient reported outcomes and functional parameters in difficult-to-treat patients with severe asthma: Data from a real-life cohort
In the last decade, an increasing number of randomized controlled trials (RCTs) on biologic therapy in patients with severe asthma have included patient-reported outcomes (PROs) as secondary efficacy measures. The majority of these RCTs showed a benefit in symptoms and quality of life. However, the magnitude of this benefit remains uncertain, because it rarely exceeded the minimal important difference (MID), owing to a significant improvement in the control group (placebo effect). Real-life studies on biologic therapies assessing PRO are scarce. They may support and integrate RCT results through their different experimental design. This real-life retrospective study provides data on 15 patients with difficult-to-treat severe eosinophilic asthma treated with benralizumab up to 6 months. Asthma quality of life questionnaire (AQLQ) and asthma control test (ACT) were assessed and administered at each visit to minimize the Hawthorne effect. Changes in general accepted efficacy measures, such as forced expiratory volume in 1 s (FEV1), peak expiratory flux (PEF), exacerbation rate and blood eosinophils, from baseline were also assessed. AQLQ and ACT improved from 3.9 ± 0.4 to 5.2 ± 0.4 and from15.6 ± 5.7 to 18.1 ± 5.6, respectively. FEV1 increased of about 250 ml (+14%). PEF increased from 288 ± 107 to 333 ± 133 l/min. The number of exacerbations requiring OCS courses decreased from 2.8 ± 2.2 to 0.5 ± 0.8. Eosinophil counts dropped to 25.6 ± 15 cells/microliter. In conclusion, most patients reported improvements in AQLQ and ACT greater than MID, suggesting that these outcome represent a sensitive tool in real-life effectiveness studies. Our approach reduced the limitations of transition questions and the Hawthorne effect, increasing findings reliability
Novel inhibitory effect on 5-lipoxygenase activity by the anti-asthma drug montelukast
5-Lipoxygenase is the key enzyme in the biosyntesis ok leukotrienes, powerful lipid mediators involved in inflammation, cell-cell communication, and other important physiological and pathological conditions. Particularly, cystenyl-leukotrienes have been recognized as playing a significant role in the pathophysiology of asthma and potent and effective Cys-LT1 receptor antagonists have been developed for the treatment of this illness. Here we report that montelukast, a structural Cys-LT1 receptor antagonist, also exerts a substantial and apparently direct inhibitory effect on 5-lipoxygenase activity in vitro, at concentrations in the lowel micromolar range, which are of potential therapeutic relevance. Thus, when human mast cells HMC-1 were stimulated with the Ca ionophore A23187 in the presence of montelukast (up to 100 microM) a substantial decline in 5-lipoxygenase biosyntesia was observed. Similar results were obtained in the rat mast cell-like RBL-1 cell model (IC50=2,5 microM) and in human polymorphonuclear leukocytes. Moreover, montelukast directly inhibited human recombinant 5-lipoxygenase. Kinetic experiments revealed that the inhibition was of the non-competitive type, suggesting that montelukast binds a yet undefined allosteric site on 5-lipoxygenase. 5-Lipoxygenase inhibition by montelukast appears to be highly selective since the drug had no effects on other enzymes of the leukotriene cascade, viz. LTC4 synthase and LTA hydrolase
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