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Karvonen T, Sepponen-Lavikko A, Holm K, Schultz R, Moilanen E, Lehtimäki L. Onset of action of inhaled glucocorticoids on bronchial and alveolar nitric oxide output. J Breath Res 2020; 15:016008. [PMID: 33045700 DOI: 10.1088/1752-7163/abc054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Fractional exhaled nitric oxide (FENO) is a marker of airway inflammation. Measuring FENO at multiple flow rates enables calculation of NO parameters: bronchial NO output (J awNO), bronchial wall (C awNO) and alveolar (C ANO) NO concentrations, and bronchial diffusion factor of NO (D awNO). FENO is known to rapidly reduce after the commencement of inhaled corticosteroid (ICS) treatment. However, little is known on the effect of ICS on the other NO parameters. We assessed (1) the onset of action of ICS treatment on the NO parameters and (2) whether the changes in bronchial NO output are due to changes in bronchial wall NO concentration or diffusion factor. FENO and other NO parameters were measured at baseline and after 1, 3 and 7 d of treatment with inhaled fluticasone propionate 250 μg b.i.d. in 23 allergic children with a history of asthma-like symptoms. There was a decrease in J awNO (from 680 (244/1791) (median (1st/3rd quartile)) to 357 (165/753) pl s-1, p < 0.001) and FENO50( from 13.8 (7.5/35) to 8.3 (5.36/17.0) ppb, p < 0.001) in 3 d from the first dose of ICS. Also, C awNO seemed to reduce after 3 d (from 171 (89/328) to 79 (54/157) ppb, p = 0.041), while D awNO remained unchanged. Furthermore, C ANO reduced during the 7 d treatment (from 3.0 (2.0/5.0) to 2.3 (1.9/2.6) ppb, p = 0.004). ICS treatment reduced FENO50 and J awNO rapidly and the decline was caused by decreased bronchial wall NO concentration while bronchial NO diffusion factor remained unchanged. These findings suggest that C awNO could be a more specific marker of airway inflammation and treatment response than J awNO or FENO50, which are both determined also by D awNO that seems to be resistant to the treatment with ICS.
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Affiliation(s)
- Tuomas Karvonen
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
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Busby J, Khoo E, Pfeffer PE, Mansur AH, Heaney LG. The effects of oral corticosteroids on lung function, type-2 biomarkers and patient-reported outcomes in stable asthma: A systematic review and meta-analysis. Respir Med 2020; 173:106156. [PMID: 32979621 DOI: 10.1016/j.rmed.2020.106156] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 09/03/2020] [Accepted: 09/10/2020] [Indexed: 01/02/2023]
Abstract
BACKGROUND Several studies have investigated the physiological effect of OCS in stable asthma, however these have included heterogeneous populations and outcomes. This paper is the first to combine their results. METHODS We searched Medline, Embase and Web of Science databases for studies reporting the impact of OCS on FEV1, FVC, blood eosinophils, fractional exhaled nitric oxide (FeNO), Asthma Control Questionnaire (ACQ) score or Asthma Quality Of Life Questionnaire (AQLQ) score in stable asthma. We extracted data on the correlates of OCS response. RESULTS 61 studies, comprising 1608 patients, were included. FEV1 was improved by 9% (95% CI: 7, 11). There were stronger increases in FEV1 among those with a mean baseline FEV1<60% predicted (19%, 95% CI: 13, 24). Despite these improvements, substantial residual impairment remained after treatment. Blood eosinophils were reduced by 76% (95% CI: 63, 88) with larger decreases in studies of corticosteroid-naïve patients (93%, 95% CI: 73,100). Sputum eosinophils were reduced by 89% (95% CI: 79, 98) while FeNO was decreased by 35% (95% CI: 28, 41). ACQ scores were reduced by 20% (95% CI: 11, 29). Patients with higher baseline lung function impairment, sputum eosinophils, blood eosinophils and FeNO had improved OCS response. INTERPRETATION OCS consistently improves lung function, reduces markers of type-2 inflammation, and alleviates asthma symptoms. However, substantial residual impairment remained following treatment and mean improvements were below the minimally important clinically difference. Patients with increased markers of type-2 inflammation are more responsive to treatment, suggesting these should be used to better target OCS use.
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Affiliation(s)
| | | | | | - Adel H Mansur
- University Hospitals Birmingham NHS Foundation Trust, University of Birmingham, UK
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3
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Karvonen T, Lehtimäki L. Flow-independent nitric oxide parameters in asthma: a systematic review and meta-analysis. J Breath Res 2019; 13:044001. [PMID: 31239409 DOI: 10.1088/1752-7163/ab2c99] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
INTRODUCTION Fractional exhaled nitric oxide (FENO) has been proposed as a non-invasive marker of inflammation in the lungs. Measuring FENO at several flow rates enables the calculation of flow independent NO-parameters that describe the NO-exchange dynamics of the lungs more precisely. The purpose of this study was to compare the NO-parameters between asthmatics and healthy subjects in a systematic review and meta-analysis. METHODS A systematic search was performed in Ovid Medline, Web of Science, Scopus and Cochrane Library databases. All studies with asthmatic and healthy control groups with at least one NO-parameter calculated were included. RESULTS From 1137 identified studies, 33 were included in the meta-analysis. All NO-parameters (alveolar NO concentration (CANO), bronchial flux of NO (JawNO), bronchial mucosal NO concentration (CawNO) and bronchial wall NO diffusion capacity (DawNO)) were found increased in glucocorticoid-treated and glucocorticoid-naïve asthma. JawNO and CANO were most notably increased in both study groups. Elevation of DawNO and CawNO seemed less prominent in both asthma groups. DISCUSSION We found that all the NO-parameters are elevated in asthma as compared to healthy subjects. However, results were highly heterogenous and the evidence on CawNO and DawNO is still quite feeble due to only few studies reporting them. To gain more knowledge on the NO-parameters in asthma, nonlinear methods and standardized study protocols should be used in future studies.
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Affiliation(s)
- Tuomas Karvonen
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
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Ahovuo-Saloranta A, Csonka P, Lehtimäki L. Basic characteristics and clinical value of FeNO in smoking asthmatics-a systematic review. J Breath Res 2019; 13:034003. [PMID: 30861509 DOI: 10.1088/1752-7163/ab0ece] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Fractional exhaled nitric oxide (FeNO) reflects eosinophilic airway inflammation and it can be used to diagnose and phenotype asthma and predict treatment responses. However, smoking decreases FeNO and it is not clear if FeNO has clinical value in smoking subjects with asthma. We conducted a systematic review focusing on four basic characteristics and five clinical questions on using FeNO in smokers with asthma. At least two authors independently screened search results, extracted data and assessed the quality of the included studies. Data were synthesised mainly by qualitative methods. Twenty-two studies were included. FeNO is lower in smoking than in non-smoking asthmatics, but importantly FeNO is higher in untreated smoking asthmatics than in healthy smokers. Information was incomplete but there is some indication that FeNO might be useful in detecting eosinophilic airway inflammation and in diagnosing asthma in smoking subjects. There was no data available to four of the five clinical questions. In conclusion, at the moment there is insufficient data to give specific guidelines on using FeNO in smoking subjects, but although smoking decreases FeNO it does not seem to make FeNO measurement redundant. FeNO is also associated with asthma in smokers and current results encourage conducting clinical trials on FeNO in smokers with asthma.
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Lázár Z, Horváth P, Puskás R, Gálffy G, Losonczy G, Horváth I, Bikov A. A suitable protocol for measuring alveolar nitric oxide in asthma with differing severity to assess peripheral airways inflammation. J Asthma 2018; 56:584-593. [PMID: 29923757 DOI: 10.1080/02770903.2018.1477957] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
OBJECTIVE Extended nitric oxide (NO) analysis offers the partitioned monitoring of inflammation in central and peripheral airways. Different mathematical models are used to estimate pulmonary NO dynamics in asthma with variable results and limitations. We aimed to establish a protocol for extended NO analysis in patients with differing asthma severity. METHODS Forty patients with stable asthma and 25 matched control subjects were recruited. Exhaled NO was measured at constant flow rates between 10 and 300 mL/s. Twelve controls performed NO measurements weekly for 4 weeks. RESULTS The proportions of patients with technically acceptable measurements at 10-30-50-100-150-200-250-300 mL/s exhalation flow rates were 8-58-100-98-98-95-90-80%, respectively. Alveolar NO (CANO) and total flux of NO in the conducting airways (JawNO) were calculated with the linear method from NO values measured at 100-150-200-250 mL/s exhalation flows. The mean intrasubject bias for JawNO and CANO in controls was 0.16 nL/s and 0.85 ppb, respectively. Both JawNO (1.31/0.83-2.97/vs. 0.70/0.54-0.87/nL/s, p < 0.001) and CANO (4.08/2.63-7.16/vs. 2.42/1.83-2.89/ppb, p < 0.001) were increased in patients with asthma compared to controls. In patients, CANO correlated with RV/TLC (r = 0.58, p < 0.001), FEF25-75% (p = 0.02, r = -0.36) and DL,CO (r = -0.46, p = 0.004). JawNO was not related to lung function parameters. CONCLUSIONS Calculation of alveolar NO concentration with the linear method from values obtained at medium flow rates (100-250 mL/s) is feasible even in asthmatic patients with severe airflow limitation and may provide information on small airways dysfunction in asthma.
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Affiliation(s)
- Zsófia Lázár
- a Department of Pulmonology , Semmelweis University , 1/c Diós árok
| | - Péter Horváth
- a Department of Pulmonology , Semmelweis University , 1/c Diós árok
| | - Rita Puskás
- a Department of Pulmonology , Semmelweis University , 1/c Diós árok
| | - Gabriella Gálffy
- a Department of Pulmonology , Semmelweis University , 1/c Diós árok
| | - György Losonczy
- a Department of Pulmonology , Semmelweis University , 1/c Diós árok
| | - Ildikó Horváth
- b National Korányi Institute of Pulmonology , 1 Pihenő Street , Budapest , Hungary
| | - András Bikov
- a Department of Pulmonology , Semmelweis University , 1/c Diós árok
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Giovannelli J, Chérot-Kornobis N, Hulo S, Ciuchete A, Clément G, Amouyel P, Matran R, Dauchet L. Both exhaled nitric oxide and blood eosinophil count were associated with mild allergic asthma only in non-smokers. Clin Exp Allergy 2016; 46:543-54. [PMID: 26542195 DOI: 10.1111/cea.12669] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Revised: 09/02/2015] [Accepted: 09/28/2015] [Indexed: 01/24/2023]
Abstract
BACKGROUND The fractional exhaled nitric oxide (FENO) and the blood eosinophil count (B-eos) are markers of eosinophilic inflammation used in the diagnosis and management of asthma. The relationships between smoking cigarette and both FENO and B-eos are complex and raise questions about the association between these markers and asthma in smokers. OBJECTIVE To determine the relationships between both FENO and B-eos on one hand and asthma and atopy on the other, according to smoking status. METHODS FENO and B-eos were measured in, respectively, 1579 and 1496 of the 1607 middle-aged adults randomly selected from the general population in the cross-sectional ELISABET survey. Allergic asthma was defined as asthma (a self-report of physician-diagnosed asthma, and wheezing in the previous 12 months or the use of asthma medications) with atopy (allergic rhinitis or hayfever in the previous 12 months, or a previous positive prick test or allergen desensitization therapy). Non-allergic asthma was defined as asthma without atopy. RESULTS The analysis included 812 (51.4%) never, 473 (30%) former and 294 (18.6%) current smokers. A total of 490 (32%) participants were atopic, 80 (5.1%) had allergic asthma, and 31 (2%) had non-allergic asthma. Only 16.2% (18/111) of asthmatics were treated with glucocorticoid inhalants, suggesting that among them a majority of participants had mild asthma. A positive interaction between smoking status and allergic asthma was observed in multivariate models explaining FENO (P = 0.003) and B-eos (P = 0.001). Thus, compared to those without allergic asthma, participants with allergic asthma had higher FENO values (+ 63.4%, 95% CI = [39; 92]) and higher B-eos (+ 63.2% [38.2; 92.7]) in never and former smokers, but not in current smokers. Lastly, an analysis of receiver-operating characteristic curves showed that each of the two markers was able to discriminate moderately allergic asthma but only in non-smokers. CONCLUSIONS & CLINICAL RELEVANCE FENO and B-eos were associated with the presence of mild allergic asthma only in non-smokers, not in current smokers. These findings raise questions about the clinical value of FENO and B-eos in smokers.
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Affiliation(s)
- J Giovannelli
- Faculté de Médecine Henri Warembourg, University of Lille, Lille Cedex, France.,University Hospital of Lille, Lille, France.,Pasteur Institute of Lille, INSERM U1167 RID-AGE, Lille, France
| | - N Chérot-Kornobis
- Faculté de Médecine Henri Warembourg, University of Lille, Lille Cedex, France.,University Hospital of Lille, Lille, France
| | - S Hulo
- Faculté de Médecine Henri Warembourg, University of Lille, Lille Cedex, France.,University Hospital of Lille, Lille, France
| | - A Ciuchete
- Pasteur Institute of Lille, INSERM U1167 RID-AGE, Lille, France
| | - G Clément
- Faculté de Médecine Henri Warembourg, University of Lille, Lille Cedex, France.,Pasteur Institute of Lille, INSERM U1167 RID-AGE, Lille, France
| | - P Amouyel
- Faculté de Médecine Henri Warembourg, University of Lille, Lille Cedex, France.,University Hospital of Lille, Lille, France.,Pasteur Institute of Lille, INSERM U1167 RID-AGE, Lille, France
| | - R Matran
- Faculté de Médecine Henri Warembourg, University of Lille, Lille Cedex, France.,University Hospital of Lille, Lille, France
| | - L Dauchet
- Faculté de Médecine Henri Warembourg, University of Lille, Lille Cedex, France.,University Hospital of Lille, Lille, France.,Pasteur Institute of Lille, INSERM U1167 RID-AGE, Lille, France
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Taguchi L, Pinheiro NM, Olivo CR, Choqueta-Toledo A, Grecco SS, Lopes FDTQS, Caperuto LC, Martins MA, Tiberio IFLC, Câmara NO, Lago JHG, Prado CM. A flavanone from Baccharis retusa (Asteraceae) prevents elastase-induced emphysema in mice by regulating NF-κB, oxidative stress and metalloproteinases. Respir Res 2015; 16:79. [PMID: 26122092 PMCID: PMC4489216 DOI: 10.1186/s12931-015-0233-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 06/08/2015] [Indexed: 01/02/2023] Open
Abstract
Background Pulmonary emphysema is characterized by irreversible airflow obstruction, inflammation, oxidative stress imbalance and lung remodeling, resulting in reduced lung function and a lower quality of life. Flavonoids are plant compounds with potential anti-inflammatory and antioxidant effects that have been used in folk medicine. Our aim was to determine whether treatment with sakuranetin, a flavonoid extracted from the aerial parts of Baccharis retusa, interferes with the development of lung emphysema. Methods Intranasal saline or elastase was administered to mice; the animals were then treated with sakuranetin or vehicle 2 h later and again on days 7, 14 and 28. We evaluated lung function and the inflammatory profile in bronchoalveolar lavage fluid (BALF). The lungs were removed to evaluate alveolar enlargement, extracellular matrix fibers and the expression of MMP-9, MMP-12, TIMP-1, 8-iso-PGF-2α and p65-NF-κB in the fixed tissues as well as to evaluate cytokine levels and p65-NF-κB protein expression. Results In the elastase-treated animals, sakuranetin treatment reduced the alveolar enlargement, collagen and elastic fiber deposition and the number of MMP-9- and MMP-12-positive cells but increased TIMP-1 expression. In addition, sakuranetin treatment decreased the inflammation and the levels of TNF-α, IL-1β and M-CSF in the BALF as well as the levels of NF-κB and 8-iso-PGF-2α in the lungs of the elastase-treated animals. However, this treatment did not affect the changes in lung function. Conclusion These data emphasize the importance of oxidative stress and metalloproteinase imbalance in the development of emphysema and suggest that sakuranetin is a potent candidate that should be further investigated as an emphysema treatment. This compound may be useful for counteracting lung remodeling and oxidative stress and thus attenuating the development of emphysema. Electronic supplementary material The online version of this article (doi:10.1186/s12931-015-0233-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Laura Taguchi
- Department of Biological Science, Universidade Federal de São Paulo, Rua Artur Riedel, 275 - Eldorado, Diadema, SP, Brazil
| | - Nathalia M Pinheiro
- Department of Medicine, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Clarice R Olivo
- Department of Medicine, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | | | - Simone S Grecco
- Department of Exact and Earth Sciences, Universidade Federal de São Paulo, Diadema, Brazil
| | - Fernanda D T Q S Lopes
- Department of Medicine, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Luciana C Caperuto
- Department of Biological Science, Universidade Federal de São Paulo, Rua Artur Riedel, 275 - Eldorado, Diadema, SP, Brazil
| | - Mílton A Martins
- Department of Medicine, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Iolanda F L C Tiberio
- Department of Medicine, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Niels O Câmara
- Department of Immunology, Biological Institute, Universidade de São Paulo, São Paulo, Brazil
| | - João Henrique G Lago
- Department of Exact and Earth Sciences, Universidade Federal de São Paulo, Diadema, Brazil
| | - Carla M Prado
- Department of Biological Science, Universidade Federal de São Paulo, Rua Artur Riedel, 275 - Eldorado, Diadema, SP, Brazil. .,Department of Medicine, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.
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Bartminski G, Crossley M, Turcanu V. Novel biomarkers for asthma stratification and personalized therapy. Expert Rev Mol Diagn 2014; 15:415-30. [PMID: 25479456 DOI: 10.1586/14737159.2015.988613] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A stepwise pharmacological treatment is currently recommended for all asthma patients and is personalized mainly on disease severity, aiming for the lowest disease-controlling step. Nevertheless, asthma comprises several related pathologies with similar clinical manifestations resulting from distinct underlying mechanisms. Therefore novel biomarkers could lead to asthma stratification and thus improve upon the current stepwise approach. The aim of this review is to update the reader with regard to different assays proposed in the recent asthma literature for measuring potential biomarkers for patient stratification and treatment personalization. Promising biomarkers are sputum eosinophils, serum periostin and exhaled nitric oxide. Periostin could differentiate between Th2-high and Th2-low asthma (Th2-high patients are more responsive to glucocorticoids) and the less-defined asthma types which often present a therapeutic challenge. Several other biomarkers, mainly cytokines, leukotrienes and exhaled air components, can be quantified in body fluids and exhaled breath and could also be useful for asthma stratification.
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Affiliation(s)
- Grzegorz Bartminski
- Department of Asthma, Allergy and Lung Biology, King's College London 5th floor Tower Wing, Guy's Hospital, London Bridge, SE1 9RT, UK
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9
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Exhaled nitric oxide in interstitial lung diseases. Respir Physiol Neurobiol 2014; 197:46-52. [DOI: 10.1016/j.resp.2014.03.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Revised: 03/21/2014] [Accepted: 03/21/2014] [Indexed: 11/22/2022]
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Clinical outcomes and inflammatory biomarkers in current smokers and exsmokers with severe asthma. J Allergy Clin Immunol 2013; 131:1008-16. [PMID: 23419540 DOI: 10.1016/j.jaci.2012.12.1574] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Revised: 12/07/2012] [Accepted: 12/18/2012] [Indexed: 11/23/2022]
Abstract
BACKGROUND Clinical outcomes are worse in current smokers and exsmokers with mild-to-moderate asthma compared with never smokers, but little is known about the influence of smoking status in patients with severe asthma. OBJECTIVES We sought to examine the association of current or previous cigarette smoking with clinical and inflammatory variables in patients with severe asthma. METHODS We compared patients' demographics, disease characteristics, and biomarkers of inflammation in current smokers (n=69 [9%]), exsmokers (n=210 [28%]), and never smokers (n=461 [62%]) with severe asthma (n=760) recruited to the British Thoracic Society Severe Asthma Registry. RESULTS Current smokers had poorer asthma control, more unscheduled health care visits, more rescue courses of oral steroids, and higher anxiety and depression scale scores than exsmokers or never smokers. Current smokers had a reduced proportion of sputum eosinophils compared with never smokers (1% and 4%, respectively) and lower fraction of expired nitric oxide (50 mL/s; 14 ppb and 35 ppb, respectively). Exsmokers compared with never smokers had an increased proportion of sputum neutrophils (59% and 43%, respectively) but a similar proportion of sputum eosinophils (3%) and fraction of expired nitric oxide (50 mL/s; 35 ppb). Both current smokers and exsmokers had reduced serum specific IgE levels to several common environmental allergens. CONCLUSION Current smokers with severe asthma exhibit worse clinical and health care outcomes compared with exsmokers and never smokers with severe asthma. Their inflammatory profiles in sputum and blood differ.
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Malinovschi A, Backer V, Harving H, Porsbjerg C. The value of exhaled nitric oxide to identify asthma in smoking patients with asthma-like symptoms. Respir Med 2012; 106:794-801. [PMID: 22405608 DOI: 10.1016/j.rmed.2012.02.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 02/13/2012] [Accepted: 02/17/2012] [Indexed: 01/13/2023]
Abstract
BACKGROUND The fraction of nitric oxide in exhaled air (FeNO) is used in asthma diagnosis and management. Smoking reduces FeNO and 20-35% of asthmatics are smoking. However no guidelines exist on the diagnostic value of FeNO in smokers. Therefore we assessed the value of FeNO to diagnose asthma in a population of subjects with asthma-like symptoms and different smoking habits. METHODS Measurements of FeNO, lung function, bronchial responsiveness and allergy testing were performed in 282 subjects (108 never-, 62 ex- and 112 current smokers) aged 14-44 years, with symptoms suggestive of asthma. These subjects were a subset of subjects reporting respiratory symptoms (n = 686) in a random population sample (n = 10,400). RESULTS A diagnosis of asthma was given to 96 of the 282 subjects. Subjects with asthma had higher FeNO levels than subjects with non-specific asthma symptoms in all three smoking strata (p < 0.001), with a percentual increase of FeNO by 76% in never-, 71% in ex- and 60% in current smokers. The area under the ROC-curve was similar in never-, ex- and current smokers (0.72 vs. 0.74 vs. 0.70). The cut-offs were approximately 30% lower for either 90% specificity (22 vs. 31 ppb) or 90% sensitivity (7 vs. 10 ppb) in current vs. never-smokers. CONCLUSIONS FeNO could differentiate asthmatic subjects from non-asthmatic subjects with asthma-like symptoms equally well in both never- and current smokers within a random population sample. The FeNO cut-off levels needed in order to achieve high sensitivity or specificity were lower in current smokers.
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Affiliation(s)
- Andrei Malinovschi
- Department of Medical Sciences, Clinical Physiology, Uppsala University, Uppsala, Sweden.
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