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| 2. |
- Gyllfors, Pär, et al.
(författare)
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Bronchial responsiveness to leukotriene D4 is resistant to inhaled fluticasone propionate
- 2006
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Ingår i: Journal of Allergy and Clinical Immunology. - : Elsevier BV. - 0091-6749 .- 1097-6825. ; 118:1, s. 78-83
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Inhaled corticosteroids are highly effective in asthma, reducing inflammatory markers and bronchial hyperresponsiveness. Cysteinyl-leukotrienes are major mediators of airway obstruction and display proinflammatory effects. Although the synthesis of leukotrienes is not affected by corticosteroid treatment, the influence of corticosteroids on the leukotriene pathway remains unresolved. OBJECTIVE: We investigated whether or not bronchial responsiveness to leukotriene (LT) D(4) is reduced by fluticasone propionate in subjects with asthma. METHODS: In 13 subjects with mild asthma, inhalation challenges with methacholine and LTD(4) were performed on consecutive days before and after 2 weeks of treatment with inhaled fluticasone 500 mug, twice daily, in a double-blind, randomized, placebo-controlled study with crossover design and 3 weeks of washout between periods. Exhaled nitric oxide was measured as a marker of corticosteroid responsiveness, and baseline urinary LTE(4) concentrations as an index of cysteinyl-leukotriene biosynthesis. RESULTS: Fluticasone produced a significant decrease in methacholine responsiveness, corresponding to 2.6-fold shift in the PD(20) FEV(1), and a significant reduction in the levels of exhaled nitric oxide. By contrast, bronchial responsiveness to LTD(4) in the same subjects was unaffected by fluticasone, as were urinary LTE(4) concentrations. CONCLUSION: These new data indicate that neither the biosynthesis nor the actions of leukotrienes appear to be sensitive to inhaled corticosteroids. CLINICAL IMPLICATIONS: The study provides mechanistic support for the additive therapeutic efficacy of antileukotrienes and inhaled corticosteroids in asthma.
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- Higashi, Ai, et al.
(författare)
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Challenge of isolated sputum cells supports in vivo origin of intolerance reaction to aspirin/non-steroidal anti-inflammatory drugs in asthma
- 2012
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Ingår i: International Archives of Allergy and Immunology. - : S. Karger AG. - 1018-2438 .- 1423-0097. ; 158:3, s. 299-306
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Tidskriftsartikel (refereegranskat)abstract
- Background: There is no in vitro test to diagnose aspirin-intolerant asthma (AIA). The aim of this study was to test if challenge with aspirin of sputum cells from subjects with AIA triggers the release of cysteinyl leukotrienes (CysLTs), known to be mediators of bronchoconstriction in AIA. Methods: Sputum induction was performed at baseline and at another visit 2 h after a lysine-aspirin bronchoprovocation in 10 subjects with AIA and 9 subjects with aspirin-tolerant asthma (ATA). The isolated sputum cells were incubated for ex vivo challenge. Results: Release of CysLTs by sputum cells from patients with AIA was not induced by lysine-aspirin ex vivo, neither when cells were collected at baseline nor in sputum cells recovered after lysine-aspirin-induced bronchoconstriction, whereas release of CysLTs from sputum cells was triggered by an ionophore on both occasions. However, the CysLT levels elicited by the ionophore were higher in the AIA group both at baseline (AIA vs. ATA: 3.3 vs. 1.6 ng/million cells; p < 0.05) and after the lysine-aspirin bronchoprovocation (3.9 vs. 1.7 ng/million cells; p < 0.05). This difference in the amount of CysLTs released between the groups appeared to be related to the number of eosinophils. Conclusions: Intolerance to aspirin could not be triggered in sputum cells isolated from subjects with AIA. Together with the previous inability to demonstrate intolerance to non-steroidal anti-inflammatory drugs in isolated blood cells, these results support the requirement of tissue-resident cells in the adverse reaction. However, ex vivo stimulation of sputum cells may be developed into a new test of capacity for LT release in inflammatory cells recovered from airways.
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| 4. |
- James, Anna, et al.
(författare)
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The influence of aspirin on release of eoxin C4, leukotriene C4 and 15-HETE, in eosinophilic granulocytes isolated from patients with asthma
- 2013
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Ingår i: International Archives of Allergy and Immunology. - : S. Karger AG. - 1018-2438 .- 1423-0097. ; 162:2, s. 135-42
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 5. |
- Gulliksson, Magdalena, et al.
(författare)
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Expression of 15-lipoxygenase type-1 in human mast cells
- 2007
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Ingår i: Biochimica et Biophysica Acta. - : Elsevier BV. - 0006-3002 .- 1878-2434. ; 1771:9, s. 1156-65
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Tidskriftsartikel (refereegranskat)abstract
- Mast cells play a key role in the pathophysiology of asthma. These cells exert their effector functions by releasing a variety of proinflammatory and immunoregulatory compounds. Mast cells infiltrate the bronchial epithelium and smooth muscle to a higher degree in patients with asthma compared to control subjects. 15-Lipoxygenase type-1 (15-LO-1) is a prooxidant enzyme which is expressed in asthmatic lungs leading to formation of pro- and anti-inflammatory mediators. Here we report that interleukin-4 (IL-4) induced the expression of 15-LO-1 in human cord blood derived mast cells (CBMC) as demonstrated by RT-PCR, western blot and immunocytochemistry. The major metabolite of arachidonic acid formed via the 15-LO pathway in IL-4 treated CBMC was identified as 15-ketoeicosatetraenoic acid (15-KETE, also named 15-oxo-ETE) with smaller amounts of 15-hydroxyeicosatetraenoic acid (15-HETE) as identified by HPLC and mass spectrometry (MS/MS). Furthermore, immunohistochemical stainings demonstrated the expression of 15-LO-1 in mast cells in lung and skin in vivo. Osmotic activation of CBMC with mannitol resulted in activation of the 15-LO-1 pathway. In conclusion, the expression of 15-LO-1 and release of 15-LO-1 derived products by mast cells may contribute to the role of these cells in asthma and other inflammatory diseases.
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