Induced sputum to assess airway inflammation: a study of reproducibility

Spanevello, Antonio; Migliori, Giovanni Battista; Sharara, Abdelmonem M.; Ballardini, Luigi; Bridge, Pete; Pisati, P.; Neri, Margherita; Ind, P W

doi:10.1111/j.1365-2222.1997.tb01150.x

Cited by 102 publications

(73 citation statements)

References 18 publications

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“…In healthy volunteers the reproducibility of total cell count was high as well as that of eosinophils, neutrophils and macrophages. Consistent with previous studies the lymphocyte count was not reproducible [17]. The fairly small amount of saline used in the experimental procedure to limit the inhalation time and to avoid the dilution of samples also enabled the measurements of cytokines in induced sputum.…”

Section: Discussionsupporting

confidence: 64%

Reproducibility of measurements of exhaled NO, and cell count and cytokine concentrations in induced sputum

Purokivi

Randell

Hirvonen³

et al. 2000

Eur Respir J

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Reproducibility of measurements of exhaled NO, and cell count and cytokine concentrations in induced sputum. M. Purokivi, J. Randell, M-R. Hirvonen, H. Tukiainen. #ERS Journals Ltd 2000. ABSTRACT: Sputum induction is a noninvasive, well-tolerated method for studying airway inflammation. When induction with hypertonic saline is repeated at short time-intervals (<24 h), the cell profile of sputum has not been reproducible. To determine the proper interval between sampling cell profiles and cytokine contents of sputum samples that had been induced 48 h apart, were compared. In addition, the inducible nitric oxide synthase (iNOS) expression of sputum cells was compared to the levels of exhaled nitric oxide (NO).Sputum induction and measurement of exhaled NO was performed in 31 healthy nonatopic volunteers. Cell differentials were counted. Concentrations of interleukin (IL)-4, IL-6, tumour necrosis factor (TNF)a, eosinophil cationic protein (ECP) were measured in sputum supernatant, and iNOS was determined.Reproducibility of cell counts was high (r=0.836 total cells, r=0.762 neutrophils, r=0.966 eosinophils, r=0.742 macrophages). IL-4 (r=0.398), IL-6 (r=0.566), TNFa (r=0.658) and ECP (r=0.501) were also less reproducible in healthy volunteers. Consistent with the low levels of NO in the exhaled air (18.52.6 ppb and 19.32.8 parts per billion (ppb) on the two study days, r=0.976, p=0.0000), expression of iNOS was not detected.In conclusion, in healthy subjects, induced sputum cell counts are reproducible. Even though the success rate in nonatopic populations is relatively low, sputum induction appears to be a valid method for detecting inflammatory changes within the airways, when being performed 48 h apart. Eur Respir J 2000; 16: 242±246. There has been wide interest in developing noninvasive methods to determine lower airway inflammation in different respiratory disorders. Measurement of inflammatory mediators in induced sputum provides a direct method to investigate airway inflammation in different respiratory conditions including asthma. Sputum induction by nebulized hypertonic saline has been found to be safe and well tolerated [1±3]. However, the saline inhalation affects the production of inflammatory markers, since neutrophilia and loss of macrophages has been reported in samplings repeated within 24 h [4]. This suggests that a longer time interval is required between two samplings of induced sputum, when it is used for the evaluation of allergen challenge. Thus, the time interval in which possible effects of saline inhalation disappear, needs to be defined.Defining the cytokine profile in induced sputum could widen the view to inflammatory state of lower respiratory tract. Previously the attempts to measure cytokines by using bronchoalveolar lavage samples have failed because of dilution caused by the large volume of saline needed for sampling [5]. In sputum induction this problem is avoided, at least when low volume of nebulized saline is used [6].Since not all patients are able to produce sputum, despite ind...

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Section: Discussionsupporting

confidence: 64%

Reproducibility of measurements of exhaled NO, and cell count and cytokine concentrations in induced sputum

Purokivi

Randell

Hirvonen³

et al. 2000

Eur Respir J

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“…In line with these observations, FORESI et al [15] have recently demonstrated that a significant number of eosinophils and metachromatic cells may be present in induced sputum from subjects with seasonal allergic rhinitis. However, their findings are at variance with those of PIN et al [20] and SPANEVELLO et al [21], who failed to show a significant difference in the percentage of eosinophils in induced sputum between individuals with seasonal allergic rhinitis (studied out of the pollen season) and healthy controls. The reasons for such discrepancies might be related to diversity in the disease activity in the subjects studied or to important differences in methodology and study protocol.…”

Section: Discussioncontrasting

confidence: 56%

Bronchial hyperresponsiveness and airway inflammation markers in nonasthmatics with allergic rhinitis

et al. 2000

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Bronchial hyperresponsiveness (BHR) is a characteristic feature of asthma which is often associated with airways inflammation. However, some patients with allergic rhinitis and no clinical evidence of asthma also exhibit BHR. This study therefore investigated whether inflammatory cell infiltrate is present in the induced sputum of nonasthmatic subjects with allergic rhinitis during the pollen season and examined its relationship with airway hyperresponsiveness to inhaled methacholine and adenosine 5'-monophosphate (AMP).Twenty subjects (12 allergic rhinitis, eight nonallergic controls) underwent methacholine and AMP challenge and sputum induction with hypertonic saline on separate days. Cell differentials were calculated from whole sputum samples.A significantly greater number of eosinophils was found in the sputum of nonasthmatic subjects with allergic rhinitis compared to that of nonallergic controls, their median (range) percentages being 17.5 (4±47) and 1.5 (0±5) (p<0.001) respectively. Although sputum eosinophilia failed to be significantly associated with methacholine responsiveness (rs= -0.50; p=0.095), the provocative concentration of AMP causing a 20% fall in forced expiratory volume in one second correlated strongly and significantly with the absolute number of eosinophils (rs=-0.73; p=0.007). Eosinophil cationic protein levels in the sputum of rhinitic subjects were significantly elevated compared to controls and correlated with eosinophil number (rs=0.67; p=0.017).These findings support the view that bronchial eosinophilia alone is insufficient to cause asthmatic symptoms. Diverse agonists for assessing bronchial hyperresponsiveness are selectively associated with airway inflammation in allergic rhinitis. Eur Respir J 2000; 15: 30±35.

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“…Although unusual, this finding has previously been reported in other papers 37 and many reports have described that the lymphocyte counts are poorly reproducible. 38,39 In conclusion, our results indicate that induced sputum cells collected from asthmatics displayed an increased transcription for MMP-1 and TIMP-1. This excessive transcription of matrix metalloprotease may significantly contribute to airway remodelling in asthma and suggest applying an animal model of asthma to human MMP-1 expressing transgenic mice 40 in order to investigate the precise effects of MMP-1 overexpression on the bronchial wall extracellular matrix composition in the context of a repeated allergen exposure.…”

Section: Discussionmentioning

confidence: 58%

Matrix metalloproteinases and tissue inhibitors of matrix metalloproteinases mRNA transcripts in the bronchial secretions of asthmatics

Cataldo

Guéders

Munaut

et al. 2004

Laboratory Investigation

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Asthma is a chronic inflammatory disease characterized by profound extracellular matrix changes referred to as bronchial remodelling. In this study, we evaluated matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs) mRNA expression in bronchial secretions of asthmatics and correlated MMPs modulations with the lung function as a reflection of the bronchial extracellular matrix remodelling. Quantitative RT-PCR was performed on cell pellets obtained from induced sputum in order to detect the mRNAs for MMP-1, -2, -3, -8, -9, -12, -13 TIMP-1, -2, while semiquantitative RT-PCR was performed to assess the expression of MMP-7, monocyte chemoattractant protein-1 (MCP-1) and transforming growth factor-b 1 (TGF-b 1 ). The mRNA transcripts for MMP-1, TIMP-1 and monocyte chemoattractant protein-1 (MCP-1) were increased in cell pellets of induced sputum from asthmatics when compared to controls (Po0.05), and the intensity of MMP-1 mRNA expression inversely correlated with the FEV 1 in asthmatics (r ¼ À0.49, Po0.05). The MMP-1 mRNA/TIMP-1 mRNA ratio correlated with the levels of MCP-1 mRNA in asthmatics (r ¼ 0.47, Po0.05). There were no differences between the groups with respect to mRNA coding for MMP-2, -3, -7, -8, -9, -12, -13, -14, TIMP-2 and TGF-b 1 . We conclude that cells contained in the bronchial secretions from asthmatics express higher amounts of mRNA for MMP-1 and TIMP-1, perhaps related to an increased expression of MCP-1, which might contribute to the extracellular matrix changes observed during airway remodelling.

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Induced sputum to assess airway inflammation: a study of reproducibility

Abstract: The importance of this study is the confirmation, within important statistical guidelines for a study of reproducibility, that the methods examined are reproducible and valid.

Cited by 102 publications

References 18 publications

Reproducibility of measurements of exhaled NO, and cell count and cytokine concentrations in induced sputum

Reproducibility of measurements of exhaled NO, and cell count and cytokine concentrations in induced sputum

Bronchial hyperresponsiveness and airway inflammation markers in nonasthmatics with allergic rhinitis

Matrix metalloproteinases and tissue inhibitors of matrix metalloproteinases mRNA transcripts in the bronchial secretions of asthmatics

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