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Wen Y, Xie Y, Wang C, Hua L, Zhang L, Chen P, Li H. Determination of the two-compartment model parameters of exhaled HCN by fast negative photoionization mass spectrometry. Talanta 2024; 271:125710. [PMID: 38295448 DOI: 10.1016/j.talanta.2024.125710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 01/18/2024] [Accepted: 01/22/2024] [Indexed: 02/02/2024]
Abstract
Breath exhaled hydrogen cyanide (HCN) has been identified to be associated with several respiratory diseases. Accurately distinguishing the concentration and release rate of different HCN sources is of great value in clinical research. However, there are still significant challenges due to the high adsorption and low concentration characteristics of exhaled HCN. In this study, a two-compartment kinetic model method based on negative photoionization mass spectrometry was developed to simultaneously determine the kinetic parameters including concentrations and release rates in the airways and alveoli. The influences of the sampling line diameter, length, and temperature on the response time of the sampling system were studied and optimized, achieving a response time of 0.2 s. The negative influence of oral cavity-released HCN was reduced by employing a strategy based on anatomical lung volume calculation. The calibration for HCN in the dynamic range of 0.5-100 ppbv and limit of detection (LOD) at 0.3 ppbv were achieved. Subsequently, the experiments of smoking, short-term passive smoking, and intake of bitter almonds were performed to examine the influences of endogenous and exogenous factors on the dynamic parameters of the model method. The results indicate that compared with steady-state concentration measurements, the kinetic parameters obtained using this model method can accurately and significantly reflect the changes in different HCN sources, highlighting its potential for HCN-related disease research.
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Affiliation(s)
- Yuxuan Wen
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, People's Republic of China; University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing, 100049, People's Republic of China; Liaoning Key Laboratory for Mass Spectrometry Technology and Instrumentation, Dalian 116023, People's Republic of China; Dalian Key Laboratory for Online Analytical Instrumentation, 457 Zhongshan Road, Dalian, 116023, People's Republic of China
| | - Yuanyuan Xie
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, People's Republic of China; Liaoning Key Laboratory for Mass Spectrometry Technology and Instrumentation, Dalian 116023, People's Republic of China; Dalian Key Laboratory for Online Analytical Instrumentation, 457 Zhongshan Road, Dalian, 116023, People's Republic of China
| | - Chen Wang
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, People's Republic of China; University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing, 100049, People's Republic of China; Liaoning Key Laboratory for Mass Spectrometry Technology and Instrumentation, Dalian 116023, People's Republic of China; Dalian Key Laboratory for Online Analytical Instrumentation, 457 Zhongshan Road, Dalian, 116023, People's Republic of China
| | - Lei Hua
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, People's Republic of China; Liaoning Key Laboratory for Mass Spectrometry Technology and Instrumentation, Dalian 116023, People's Republic of China; Dalian Key Laboratory for Online Analytical Instrumentation, 457 Zhongshan Road, Dalian, 116023, People's Republic of China
| | - Lichuan Zhang
- Affiliated Zhongshan Hospital of Dalian University, Dalian, People's Republic of China
| | - Ping Chen
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, People's Republic of China; Liaoning Key Laboratory for Mass Spectrometry Technology and Instrumentation, Dalian 116023, People's Republic of China; Dalian Key Laboratory for Online Analytical Instrumentation, 457 Zhongshan Road, Dalian, 116023, People's Republic of China.
| | - Haiyang Li
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, People's Republic of China; Liaoning Key Laboratory for Mass Spectrometry Technology and Instrumentation, Dalian 116023, People's Republic of China; Dalian Key Laboratory for Online Analytical Instrumentation, 457 Zhongshan Road, Dalian, 116023, People's Republic of China.
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2
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Zhou Z, Shen C, Long W, Chen J, Lu J, Gao L, Hu Y, Yu M, Wu X, Shao J. Simultaneous real-time detection of fractional exhaled nitric oxide and end-tidal carbon dioxide by quantum cascade laser absorption spectroscopy. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2024; 308:123750. [PMID: 38113557 DOI: 10.1016/j.saa.2023.123750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 11/06/2023] [Accepted: 12/08/2023] [Indexed: 12/21/2023]
Abstract
The simultaneous detection of fractional exhaled nitric oxide (FeNO) and end-tidal carbon dioxide (ETCO2) is of great importance for the distinguishing and diagnosis of asthma and chronic obstructive pulmonary disease (COPD), providing more comprehensive information on respiratory disorders. This work demonstrates a simultaneous ETCO2 and FeNO detection system based on quantum cascade laser absorption spectroscopy (QCLAS) technology was presented. The system employs wavelength modulation spectroscopy (WMS) technology and the Herriott multi-pass cell, achieving a detection limit of 2.82 ppb for nitric oxide (NO) and 0.05 % for carbon dioxide (CO2). Real-time exhalation measurements were performed on volunteers with varying ETCO2 and FeNO levels, and the results of the test can accurately distinguish whether the corresponding volunteer was healthy, had asthma or COPD. The effect of exhalation flow rate on the concentration of the two gases was explored. A range of expiratory flow rates were tested in the flow rate interval from 1 to 4 L/min, and there was always an inverse relationship between expiratory flow rate and FeNO concentration, but flow rate changes did not affect ETCO2 concentration. The results indicate that this detection system can simultaneously and effectively measure ETCO2 and FeNO concentrations in real-time.
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Affiliation(s)
- Zhiming Zhou
- Key Laboratory of Optical Information Detection and Display Technology of Zhejiang, Zhejiang Normal University, Jinhua 321004, China
| | - Chenying Shen
- Key Laboratory of Optical Information Detection and Display Technology of Zhejiang, Zhejiang Normal University, Jinhua 321004, China
| | - Wei Long
- Key Laboratory of Optical Information Detection and Display Technology of Zhejiang, Zhejiang Normal University, Jinhua 321004, China
| | - Jinling Chen
- Key Laboratory of Optical Information Detection and Display Technology of Zhejiang, Zhejiang Normal University, Jinhua 321004, China
| | - Juncheng Lu
- Key Laboratory of Optical Information Detection and Display Technology of Zhejiang, Zhejiang Normal University, Jinhua 321004, China
| | - Lu Gao
- Key Laboratory of Optical Information Detection and Display Technology of Zhejiang, Zhejiang Normal University, Jinhua 321004, China
| | - Yanyan Hu
- Jinhua Guangfu Cancer Hospital, Jinhua 321099, China
| | - Meifang Yu
- Jinhua Guangfu Cancer Hospital, Jinhua 321099, China
| | - Xiaoyu Wu
- Jinhua Guangfu Cancer Hospital, Jinhua 321099, China.
| | - Jie Shao
- Key Laboratory of Optical Information Detection and Display Technology of Zhejiang, Zhejiang Normal University, Jinhua 321004, China.
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3
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Weng J, Molshatzki N, Marjoram P, Gauderman WJ, Gilliland FD, Eckel SP. Longitudinal hierarchical Bayesian models of covariate effects on airway and alveolar nitric oxide. Sci Rep 2023; 13:5346. [PMID: 37005426 PMCID: PMC10067946 DOI: 10.1038/s41598-023-31774-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 03/16/2023] [Indexed: 04/04/2023] Open
Abstract
Biomarkers such as exhaled nitric oxide (FeNO), a marker of airway inflammation, have applications in the study of chronic respiratory disease where longitudinal studies of within-participant changes in the biomarker are particularly relevant. A cutting-edge approach to assessing FeNO, called multiple flow FeNO, repeatedly assesses FeNO across a range of expiratory flow rates at a single visit and combines these data with a deterministic model of lower respiratory tract NO to estimate parameters quantifying airway wall and alveolar NO sources. Previous methodological work for multiple flow FeNO has focused on methods for data from a single participant or from cross-sectional studies. Performance of existing ad hoc two-stage methods for longitudinal multiple flow FeNO in cohort or panel studies has not been evaluated. In this paper, we present a novel longitudinal extension to a unified hierarchical Bayesian (L_U_HB) model relating longitudinally assessed multiple flow FeNO to covariates. In several simulation study scenarios, we compare the L_U_HB method to other unified and two-stage frequentist methods. In general, L_U_HB produced unbiased estimates, had good power, and its performance was not sensitive to the magnitude of the association with a covariate and correlations between NO parameters. In an application relating height to longitudinal multiple flow FeNO in schoolchildren without asthma, unified analysis methods estimated positive, statistically significant associations of height with airway and alveolar NO concentrations and negative associations with airway wall diffusivity while estimates from two-stage methods were smaller in magnitude and sometimes non-significant.
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Affiliation(s)
- Jingying Weng
- Department of Population and Public Health Sciences, University of Southern California, 2001 N. Soto Street, SSB 202B, MC-9234, Los Angeles, CA, 90089, USA
| | - Noa Molshatzki
- Department of Population and Public Health Sciences, University of Southern California, 2001 N. Soto Street, SSB 202B, MC-9234, Los Angeles, CA, 90089, USA
| | - Paul Marjoram
- Department of Population and Public Health Sciences, University of Southern California, 2001 N. Soto Street, SSB 202B, MC-9234, Los Angeles, CA, 90089, USA
| | - W James Gauderman
- Department of Population and Public Health Sciences, University of Southern California, 2001 N. Soto Street, SSB 202B, MC-9234, Los Angeles, CA, 90089, USA
| | - Frank D Gilliland
- Department of Population and Public Health Sciences, University of Southern California, 2001 N. Soto Street, SSB 202B, MC-9234, Los Angeles, CA, 90089, USA
| | - Sandrah P Eckel
- Department of Population and Public Health Sciences, University of Southern California, 2001 N. Soto Street, SSB 202B, MC-9234, Los Angeles, CA, 90089, USA.
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Exhaled nitric oxide in early rheumatoid arthritis and effects of methotrexate treatment. Sci Rep 2022; 12:6489. [PMID: 35444250 PMCID: PMC9020158 DOI: 10.1038/s41598-022-10334-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 03/30/2022] [Indexed: 11/30/2022] Open
Abstract
Patients with established rheumatoid arthritis (RA) and disease modifying treatments have lower nitric oxide (NO) levels in the alveolar compartment (CANO) and in the airway wall (CawNO), but also higher diffusion capacities for NO in the airways (DawNO) compared to matched controls. The aim of the present study was to investigate the NO lung dynamics in patients with recent onset RA before and after immune suppression with methotrexate therapy. Patients with early RA and antibodies against anticitrullinated peptides (ACPA) were recruited. Measurement of exhaled NO and inflammatory markers in serum were performed. Clinical disease activity was evaluated with Disease Activity Score for 28 joints. Healthy individuals were used as matched controls. Data are presented as median (lower quartile, upper quartile) values. RA patients (n = 44) had lower exhaled NO (FENO50) 16 (10–24) ppb compared to controls 21 (15, 29) ppb, p = 0.013. In NO-dynamics, CANO was lower in RA patients 1.6 (1.0, 2.2) ppb compared to the control subjects 2.3 (1.3, 3.1) ppb, p = 0.007. CawNO was also lower in the RA patients 55 (24, 106) ppb compared to control subjects 124 (110, 170) ppb, p < 0.001, but DawNO was higher 17 (8, 30) mL/s and 9 (5, 11) mL/s respectively, p < 0.001. Methotrexate treatment for three months reduced disease activity, but did not change the NO dynamics. In conclusion, the altered NO dynamics of the lung in ACPA-positive RA patients are already present in the early stages of the disease before any treatments and do not change after methotrexate therapy suggesting a role in the pathogenesis.
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Exhaled and nasal NO measurement: NO in your breath doesn't imply a negative attitude! Nitric Oxide 2021; 117:34-39. [PMID: 34582941 DOI: 10.1016/j.niox.2021.09.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 09/21/2021] [Accepted: 09/24/2021] [Indexed: 11/21/2022]
Abstract
Measurement of exhaled nitric oxide (NO) and nasal nitric oxide commenced in the 1990s shortly after the scientific world learned about the endogenous production of NO and its multiple roles in physiologic and pathologic processes. Exhaled NO is an established approved clinical test in asthma that can cast light on eosinophilic airway inflammation and the response to anti-inflammatory medications e.g., inhaled corticosteroids. Nasal NO which is extremely low in primary ciliary dyskinesia is an established screening test for this condition. This review is a high-level practical guide for those wishing to use exhaled and nasal NO for research and clinical application.
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Weng J, Molshatzki N, Marjoram P, Gauderman WJ, Gilliland FD, Eckel SP. Hierarchical Bayesian estimation of covariate effects on airway and alveolar nitric oxide. Sci Rep 2021; 11:17180. [PMID: 34433846 PMCID: PMC8387480 DOI: 10.1038/s41598-021-96176-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 07/30/2021] [Indexed: 11/09/2022] Open
Abstract
Exhaled breath biomarkers are an important emerging field. The fractional concentration of exhaled nitric oxide (FeNO) is a marker of airway inflammation with clinical and epidemiological applications (e.g., air pollution health effects studies). Systems of differential equations describe FeNO—measured non-invasively at the mouth—as a function of exhalation flow rate and parameters representing airway and alveolar sources of NO in the airway. Traditionally, NO parameters have been estimated separately for each study participant (Stage I) and then related to covariates (Stage II). Statistical properties of these two-step approaches have not been investigated. In simulation studies, we evaluated finite sample properties of existing two-step methods as well as a novel Unified Hierarchical Bayesian (U-HB) model. The U-HB is a one-step estimation method developed with the goal of properly propagating uncertainty as well as increasing power and reducing type I error for estimating associations of covariates with NO parameters. We demonstrated the U-HB method in an analysis of data from the southern California Children’s Health Study relating traffic-related air pollution exposure to airway and alveolar airway inflammation.
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Affiliation(s)
- Jingying Weng
- Department of Population and Public Health Sciences, University of Southern California, 2001 N. Soto Street, SSB 202B, MC-9234, Los Angeles, CA, 90089, USA
| | - Noa Molshatzki
- Department of Population and Public Health Sciences, University of Southern California, 2001 N. Soto Street, SSB 202B, MC-9234, Los Angeles, CA, 90089, USA
| | - Paul Marjoram
- Department of Population and Public Health Sciences, University of Southern California, 2001 N. Soto Street, SSB 202B, MC-9234, Los Angeles, CA, 90089, USA
| | - W James Gauderman
- Department of Population and Public Health Sciences, University of Southern California, 2001 N. Soto Street, SSB 202B, MC-9234, Los Angeles, CA, 90089, USA
| | - Frank D Gilliland
- Department of Population and Public Health Sciences, University of Southern California, 2001 N. Soto Street, SSB 202B, MC-9234, Los Angeles, CA, 90089, USA
| | - Sandrah P Eckel
- Department of Population and Public Health Sciences, University of Southern California, 2001 N. Soto Street, SSB 202B, MC-9234, Los Angeles, CA, 90089, USA.
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7
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Karvonen T, Lehtimäki L. Effect of exhalation flow rates and level of nitric oxide output on accuracy of linear approximation of pulmonary nitric oxide dynamics. J Breath Res 2021; 15. [PMID: 33784646 DOI: 10.1088/1752-7163/abf3ab] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 03/30/2021] [Indexed: 11/11/2022]
Abstract
The method of Tsoukias and George (T and G) is a commonly used linear approximation of pulmonary nitric oxide (NO) dynamics that can be used to calculate bronchial NO output (JawNO) and alveolar NO concentration (CANO). We aimed to investigate how flow rate range in exhaled NO measurements and levels of pulmonary NO parameters affect the accuracy of the T and G method. This study has three parts. (a) A theoretical part demonstrating how different exhalation flow rates and NO parameter levels affect the accuracy of the T and G method, (b) testing how exhalation flow rate range affects the method in a sample of asthmatic and healthy subjects, and (c) a meta-analysis of published literature to test whether minimum flow rate has an association with the NO parameter values. We found that both the chosen exhalation flow rates and magnitude of the pulmonary NO parameters affect the accuracy of the T and G method. Underestimation ofJawNO increased with lower flow rates and higher bronchial diffusion factor of NO (DawNO), while overestimation of CANO increased with higher DawNO and bronchial wall NO concentration (CawNO) and lower CANO. Of the NO parameters, CANO was the most prone to bias and high DawNO was the most significant factor causing the bias. Furthermore, we found that using 40 ml s-1as the lowest flow rate in our sample and 50 ml s-1in the meta-analysis compared to 100 ml s-1resulted in higher CANO, but JawNO was not statistically significantly affected. We have provided objective evidence that not only the flow rates used but also the magnitude of NO output in the test subjects affect the accuracy of the T and G method. We suggest that flow rates below 100 ml s-1should not be used with the T and G method to maintain accuracy.
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Affiliation(s)
- Tuomas Karvonen
- Tampere University Respiratory Research Group, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Lauri Lehtimäki
- Tampere University Respiratory Research Group, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland.,Allergy Centre, Tampere University Hospital, Tampere, Finland
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Högman M, Wedholm L, Carlsson T, Carlsson M, Tonkonogi M. Differences in nitric oxide airway diffusion after maximum oxygen uptake test in asthmatic and nonasthmatic elite junior cross-country skiers. ERJ Open Res 2021; 7:00378-2020. [PMID: 33748263 PMCID: PMC7958345 DOI: 10.1183/23120541.00378-2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 11/05/2020] [Indexed: 11/30/2022] Open
Abstract
Asthma is common in cross-country skiers and is often treated with β2-agonists and inhaled corticosteroids (ICS). Exhaled nitric oxide (NO) is often used to guide ICS treatment in asthma. This study investigated the change in pulmonary NO dynamics before and after a maximum oxygen uptake (V′O2max) test. An extended NO analysis was performed among Swedish elite junior cross-country skiers (n=25), with and without declared asthma, before and after a V′O2max test using roller skis. Asthma was declared by six boys and two girls among whom five occasionally used ICSs. There were no differences in baseline NO parameters between those with and without declared asthma. The median (interquartile range) diffusion capacity over airway wall (DawNO) was 21 (17–25) mL·s−1, which is much increased for this age group. After the V′O2max test, there were statistically significant differences from the baseline fraction of exhaled NO (FENO50), NO flux from airways, DawNO and alveolar NO values; but not in the NO content in airway wall (CawNO) for all subjects together as one group. However, in the asthma group, differences were only seen in FENO50 and CawNO. Interestingly, a majority of the subjects had an increase in the DawNO. An increase in DawNO has been found with allergic asthma together with elevated CawNO. The skiers did not have elevated CawNO, which indicates an absence of inflammation in the airway wall. Modelling of lung NO production clearly shows that the asthma among our skiers is distinct from the allergic asthma in nonathletes. NO pulmonary dynamics of junior cross-country skiers with asthma respond differently to the V′O2maxtest than in those without asthma. Analysis of airway inflammation should be considered before inhaled corticosteroids are prescribed.https://bit.ly/3eWB1JZ
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Affiliation(s)
- Marieann Högman
- Dept of Medical Sciences, Respiratory, Allergy and Sleep Research, Uppsala University, University Hospital, Uppsala, Sweden
| | - Lars Wedholm
- Dept of Medicine, Falun Hospital, Falun, Sweden.,School of Education, Health and Social Studies, Dalarna University, Falun, Sweden
| | - Tomas Carlsson
- School of Education, Health and Social Studies, Dalarna University, Falun, Sweden
| | - Magnus Carlsson
- School of Education, Health and Social Studies, Dalarna University, Falun, Sweden
| | - Michail Tonkonogi
- School of Education, Health and Social Studies, Dalarna University, Falun, Sweden
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Lehtimäki L, Karvonen T, Högman M. Clinical Values of Nitric Oxide Parameters from the Respiratory System. Curr Med Chem 2021; 27:7189-7199. [PMID: 32493184 DOI: 10.2174/0929867327666200603141847] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 02/24/2020] [Accepted: 03/16/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Fractional exhaled nitric oxide (FENO) concentration reliably reflects central airway inflammation, but it is not sensitive to changes in the NO dynamics in the lung periphery. By measuring FENO at several different flow rates one can estimate alveolar NO concentration (CANO), bronchial NO flux (JawNO), bronchial wall NO concentration (CawNO) and the bronchial diffusivity of NO (DawNO). OBJECTIVE We aimed to describe the current knowledge and clinical relevance of NO parameters in different pulmonary diseases. METHODS We conducted a systematic literature search to identify publications reporting NO parameters in subjects with pulmonary or systemic diseases affecting the respiratory tract. A narrative review was created for those with clinical relevance. RESULTS Estimation of pulmonary NO parameters allows for differentiation between central and peripheral inflammation and a more precise analysis of central airway NO output. CANO seems to be a promising marker of parenchymal inflammation in interstitial lung diseases and also a marker of tissue damage and altered gas diffusion in chronic obstructive pulmonary disease and systemic diseases affecting the lung. In asthma, CANO can detect small airway involvement left undetected by ordinary FENO measurement. Additionally, CawNO and DawNO can be used in asthma to assess if FENO is increased due to enhanced inflammatory activity (increased CawNO) or tissue changes related to bronchial remodelling (altered DawNO). CONCLUSION NO parameters may be useful for diagnosis, prediction of disease progression and prediction of treatment responses in different parenchymal lung and airway diseases. Formal trials to test the added clinical value of NO parameters are needed.
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Affiliation(s)
- Lauri Lehtimäki
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland,Allergy Centre, Tampere University Hospital, Tampere, Finland
| | - Tuomas Karvonen
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Marieann Högman
- Department of Medical Sciences, Respiratory, Allergy and Sleep Research, Uppsala University, S-75185 Uppsala, Sweden
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10
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Buess A, Van Muylem A, Nonclercq A, Haut B. Modeling of the Transport and Exchange of a Gas Species in Lungs With an Asymmetric Branching Pattern. Application to Nitric Oxide. Front Physiol 2020; 11:570015. [PMID: 33362572 PMCID: PMC7758446 DOI: 10.3389/fphys.2020.570015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 10/21/2020] [Indexed: 01/25/2023] Open
Abstract
Over the years, various studies have been dedicated to the mathematical modeling of gas transport and exchange in the lungs. Indeed, the access to the distal region of the lungs with direct measurements is limited and, therefore, models are valuable tools to interpret clinical data and to give more insights into the phenomena taking place in the deepest part of the lungs. In this work, a new computational model of the transport and exchange of a gas species in the human lungs is proposed. It includes (i) a method to generate a lung geometry characterized by an asymmetric branching pattern, based on the values of several parameters that have to be given by the model user, and a method to possibly alter this geometry to mimic lung diseases, (ii) the calculation of the gas flow distribution in this geometry during inspiration or expiration (taking into account the increased resistance to the flow in airways where the flow is non-established), (iii) the evaluation of the exchange fluxes of the gaseous species of interest between the tissues composing the lungs and the lumen, and (iv) the computation of the concentration profile of the exchanged species in the lumen of the tracheobronchial tree. Even if the model is developed in a general framework, a particular attention is given to nitric oxide, as it is not only a gas species of clinical interest, but also a gas species that is both produced in the walls of the airways and consumed within the alveolar region of the lungs. First, the model is presented. Then, several features of the model, applied to lung geometry, gas flow and NO exchange and transport, are discussed, compared to existing works and notably used to give new insights into experimental data available in the literature, regarding diseases, such as asthma, cystic fibrosis, and chronic obstructive pulmonary disease.
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Affiliation(s)
- Alexandra Buess
- Transfers, Interfaces and Processes, Ecole Polytechnique de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Alain Van Muylem
- Chest Department, Erasme University Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Antoine Nonclercq
- Bio-, Electro-, and Mechanical Systems (BEAMS), Ecole Polytechnique de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Benoit Haut
- Transfers, Interfaces and Processes, Ecole Polytechnique de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
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11
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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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12
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Petralia LS, Bahl A, Peverall R, Richmond G, Couper JH, Hancock G, Robbins PA, Ritchie GAD. Accurate real-time F ENO expirograms using complementary optical sensors. J Breath Res 2020; 14:047102. [PMID: 32531773 DOI: 10.1088/1752-7163/ab9c31] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The fraction of exhaled nitric oxide (FENO) is an important biomarker for the diagnosis and management of asthma and other pulmonary diseases associated with airway inflammation. In this study we report on a novel method for accurate, highly time-resolved, real time detection of FENO at the mouth. The experimental arrangement is based on a combination of optical sensors for the determination of the temporal profile of exhaled NO and CO2 concentrations. Breath CO2 and exhalation flow are measured at the mouth using diode laser absorption spectroscopy (at 2 μm) and differential pressure sensing, respectively. NO is determined in a sidestream configuration using a quantum cascade laser based, cavity-enhanced absorption cell (at 5.2 μm) which simultaneously measures sidestream CO2. The at-mouth and sidestream CO2 measurements are used to enable the deconvolution of the sidestream NO measurement back to the at-mouth location. All measurements have a time resolution of 0.1 s, limited by the requirement of a reasonable limit of detection for the NO measurement, which on this timescale is 4.7 ppb (2 σ). Using this methodology, NO expirograms (FENOgrams) were measured and compared for eight healthy volunteers. The FENOgrams appear to differ qualitatively between individuals and the hope is that the dynamic information encoded in these FENOgrams will provide valuable additional insight into the location of the inflammation in the airways and potentially predict a response to therapy. A validation of the measurements at low-time resolution is provided by checking that results from previous studies that used a two-compartment model of NO production can be reproduced using our technology.
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Affiliation(s)
- Lorenzo S Petralia
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, United Kingdom
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13
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van den Berg MPM, Kurhade SH, Maarsingh H, Erceg S, Hulsbeek IR, Boekema PH, Kistemaker LEM, van Faassen M, Kema IP, Elsinga PH, Dömling A, Meurs H, Gosens R. Pharmacological Screening Identifies SHK242 and SHK277 as Novel Arginase Inhibitors with Efficacy against Allergen-Induced Airway Narrowing In Vitro and In Vivo. J Pharmacol Exp Ther 2020; 374:62-73. [PMID: 32269169 DOI: 10.1124/jpet.119.264341] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 03/31/2020] [Indexed: 02/02/2023] Open
Abstract
Arginase is a potential target for asthma treatment. However, there are currently no arginase inhibitors available for clinical use. Here, a novel class of arginase inhibitors was synthesized, and their efficacy was pharmacologically evaluated. The reference compound 2(S)-amino-6-boronohexanoic acid (ABH) and >200 novel arginase inhibitors were tested for their ability to inhibit recombinant human arginase 1 and 2 in vitro. The most promising compounds were separated as enantiomers. Enantiomer pairs SHK242 and SHK243, and SHK277 and SHK278 were tested for functional efficacy by measuring their effect on allergen-induced airway narrowing in lung slices of ovalbumin-sensitized guinea pigs ex vivo. A guinea pig model of acute allergic asthma was used to examine the effect of the most efficacious enantiopure arginase inhibitors on allergen-induced airway hyper-responsiveness (AHR), early and late asthmatic reactions (EAR and LAR), and airway inflammation in vivo. The novel compounds were efficacious in inhibiting arginase 1 and 2 in vitro. The enantiopure SHK242 and SHK277 fully inhibited arginase activity, with IC50 values of 3.4 and 10.5 μM for arginase 1 and 2.9 and 4.0 µM for arginase 2, respectively. Treatment of slices with ABH or novel compounds resulted in decreased ovalbumin-induced airway narrowing compared with control, explained by increased local nitric oxide production in the airway. In vivo, ABH, SHK242, and SHK277 protected against allergen-induced EAR and LAR but not against AHR or lung inflammation. We have identified promising novel arginase inhibitors for the potential treatment of allergic asthma that were able to protect against allergen-induced early and late asthmatic reactions. SIGNIFICANCE STATEMENT: Arginase is a potential drug target for asthma treatment, but currently there are no arginase inhibitors available for clinical use. We have identified promising novel arginase inhibitors for the potential treatment of allergic asthma that were able to protect against allergen-induced early and late asthmatic reactions. Our new inhibitors show protective effects in reducing airway narrowing in response to allergens and reductions in the early and late asthmatic response.
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Affiliation(s)
- M P M van den Berg
- Departments of Molecular Pharmacology (M.P.M.v.d.B., S.E., I.R.H., P.H.B., L.E.M.K., H.Me., R.G.) and Drug Design (S.H.K., A.D.), Groningen Research Institute of Pharmacy, University of Groningen. Department of Laboratory Medicine, University Medical Center Groningen (M.v.F., I.P.K.), University of Groningen, Groningen, The Netherlands; Department of Pharmaceutical Sciences, Lloyd L. Gregory School of Pharmacy, Palm Beach Atlantic University, West Palm Beach, Florida (H.Ma.); and Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands (P.H.E.)
| | - S H Kurhade
- Departments of Molecular Pharmacology (M.P.M.v.d.B., S.E., I.R.H., P.H.B., L.E.M.K., H.Me., R.G.) and Drug Design (S.H.K., A.D.), Groningen Research Institute of Pharmacy, University of Groningen. Department of Laboratory Medicine, University Medical Center Groningen (M.v.F., I.P.K.), University of Groningen, Groningen, The Netherlands; Department of Pharmaceutical Sciences, Lloyd L. Gregory School of Pharmacy, Palm Beach Atlantic University, West Palm Beach, Florida (H.Ma.); and Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands (P.H.E.)
| | - H Maarsingh
- Departments of Molecular Pharmacology (M.P.M.v.d.B., S.E., I.R.H., P.H.B., L.E.M.K., H.Me., R.G.) and Drug Design (S.H.K., A.D.), Groningen Research Institute of Pharmacy, University of Groningen. Department of Laboratory Medicine, University Medical Center Groningen (M.v.F., I.P.K.), University of Groningen, Groningen, The Netherlands; Department of Pharmaceutical Sciences, Lloyd L. Gregory School of Pharmacy, Palm Beach Atlantic University, West Palm Beach, Florida (H.Ma.); and Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands (P.H.E.)
| | - S Erceg
- Departments of Molecular Pharmacology (M.P.M.v.d.B., S.E., I.R.H., P.H.B., L.E.M.K., H.Me., R.G.) and Drug Design (S.H.K., A.D.), Groningen Research Institute of Pharmacy, University of Groningen. Department of Laboratory Medicine, University Medical Center Groningen (M.v.F., I.P.K.), University of Groningen, Groningen, The Netherlands; Department of Pharmaceutical Sciences, Lloyd L. Gregory School of Pharmacy, Palm Beach Atlantic University, West Palm Beach, Florida (H.Ma.); and Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands (P.H.E.)
| | - I R Hulsbeek
- Departments of Molecular Pharmacology (M.P.M.v.d.B., S.E., I.R.H., P.H.B., L.E.M.K., H.Me., R.G.) and Drug Design (S.H.K., A.D.), Groningen Research Institute of Pharmacy, University of Groningen. Department of Laboratory Medicine, University Medical Center Groningen (M.v.F., I.P.K.), University of Groningen, Groningen, The Netherlands; Department of Pharmaceutical Sciences, Lloyd L. Gregory School of Pharmacy, Palm Beach Atlantic University, West Palm Beach, Florida (H.Ma.); and Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands (P.H.E.)
| | - P H Boekema
- Departments of Molecular Pharmacology (M.P.M.v.d.B., S.E., I.R.H., P.H.B., L.E.M.K., H.Me., R.G.) and Drug Design (S.H.K., A.D.), Groningen Research Institute of Pharmacy, University of Groningen. Department of Laboratory Medicine, University Medical Center Groningen (M.v.F., I.P.K.), University of Groningen, Groningen, The Netherlands; Department of Pharmaceutical Sciences, Lloyd L. Gregory School of Pharmacy, Palm Beach Atlantic University, West Palm Beach, Florida (H.Ma.); and Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands (P.H.E.)
| | - L E M Kistemaker
- Departments of Molecular Pharmacology (M.P.M.v.d.B., S.E., I.R.H., P.H.B., L.E.M.K., H.Me., R.G.) and Drug Design (S.H.K., A.D.), Groningen Research Institute of Pharmacy, University of Groningen. Department of Laboratory Medicine, University Medical Center Groningen (M.v.F., I.P.K.), University of Groningen, Groningen, The Netherlands; Department of Pharmaceutical Sciences, Lloyd L. Gregory School of Pharmacy, Palm Beach Atlantic University, West Palm Beach, Florida (H.Ma.); and Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands (P.H.E.)
| | - M van Faassen
- Departments of Molecular Pharmacology (M.P.M.v.d.B., S.E., I.R.H., P.H.B., L.E.M.K., H.Me., R.G.) and Drug Design (S.H.K., A.D.), Groningen Research Institute of Pharmacy, University of Groningen. Department of Laboratory Medicine, University Medical Center Groningen (M.v.F., I.P.K.), University of Groningen, Groningen, The Netherlands; Department of Pharmaceutical Sciences, Lloyd L. Gregory School of Pharmacy, Palm Beach Atlantic University, West Palm Beach, Florida (H.Ma.); and Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands (P.H.E.)
| | - I P Kema
- Departments of Molecular Pharmacology (M.P.M.v.d.B., S.E., I.R.H., P.H.B., L.E.M.K., H.Me., R.G.) and Drug Design (S.H.K., A.D.), Groningen Research Institute of Pharmacy, University of Groningen. Department of Laboratory Medicine, University Medical Center Groningen (M.v.F., I.P.K.), University of Groningen, Groningen, The Netherlands; Department of Pharmaceutical Sciences, Lloyd L. Gregory School of Pharmacy, Palm Beach Atlantic University, West Palm Beach, Florida (H.Ma.); and Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands (P.H.E.)
| | - P H Elsinga
- Departments of Molecular Pharmacology (M.P.M.v.d.B., S.E., I.R.H., P.H.B., L.E.M.K., H.Me., R.G.) and Drug Design (S.H.K., A.D.), Groningen Research Institute of Pharmacy, University of Groningen. Department of Laboratory Medicine, University Medical Center Groningen (M.v.F., I.P.K.), University of Groningen, Groningen, The Netherlands; Department of Pharmaceutical Sciences, Lloyd L. Gregory School of Pharmacy, Palm Beach Atlantic University, West Palm Beach, Florida (H.Ma.); and Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands (P.H.E.)
| | - A Dömling
- Departments of Molecular Pharmacology (M.P.M.v.d.B., S.E., I.R.H., P.H.B., L.E.M.K., H.Me., R.G.) and Drug Design (S.H.K., A.D.), Groningen Research Institute of Pharmacy, University of Groningen. Department of Laboratory Medicine, University Medical Center Groningen (M.v.F., I.P.K.), University of Groningen, Groningen, The Netherlands; Department of Pharmaceutical Sciences, Lloyd L. Gregory School of Pharmacy, Palm Beach Atlantic University, West Palm Beach, Florida (H.Ma.); and Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands (P.H.E.)
| | - H Meurs
- Departments of Molecular Pharmacology (M.P.M.v.d.B., S.E., I.R.H., P.H.B., L.E.M.K., H.Me., R.G.) and Drug Design (S.H.K., A.D.), Groningen Research Institute of Pharmacy, University of Groningen. Department of Laboratory Medicine, University Medical Center Groningen (M.v.F., I.P.K.), University of Groningen, Groningen, The Netherlands; Department of Pharmaceutical Sciences, Lloyd L. Gregory School of Pharmacy, Palm Beach Atlantic University, West Palm Beach, Florida (H.Ma.); and Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands (P.H.E.)
| | - R Gosens
- Departments of Molecular Pharmacology (M.P.M.v.d.B., S.E., I.R.H., P.H.B., L.E.M.K., H.Me., R.G.) and Drug Design (S.H.K., A.D.), Groningen Research Institute of Pharmacy, University of Groningen. Department of Laboratory Medicine, University Medical Center Groningen (M.v.F., I.P.K.), University of Groningen, Groningen, The Netherlands; Department of Pharmaceutical Sciences, Lloyd L. Gregory School of Pharmacy, Palm Beach Atlantic University, West Palm Beach, Florida (H.Ma.); and Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands (P.H.E.)
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14
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Muchmore P, Xu S, Marjoram P, Rappaport EB, Weng J, Molshatzki N, Eckel SP. Impact of different fixed flow sampling protocols on flow-independent exhaled nitric oxide parameter estimates using the Bayesian dynamic two-compartment model. Physiol Rep 2020; 8:e14336. [PMID: 31960619 PMCID: PMC6971414 DOI: 10.14814/phy2.14336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Exhaled nitric oxide (FeNO) is an established respiratory biomarker with clinical applications in the diagnosis and management of asthma. Because FeNO depends strongly on the flow (exhalation) rate, early protocols specified that measurements should be taken when subjects exhaled at a fixed rate of 50 ml/s. Subsequently, multiple flow (or "extended") protocols were introduced which measure FeNO across a range of fixed flow rates, allowing estimation of parameters including Caw NO and CA NO which partition the physiological sources of NO into proximal airway wall tissue and distal alveolar regions (respectively). A recently developed dynamic model of FeNO uses flow-concentration data from the entire exhalation maneuver rather than plateau means, permitting estimation of Caw NO and CA NO from a wide variety of protocols. In this paper, we use a simulation study to compare Caw NO and CA NO estimation from a variety of fixed flow protocols, including: single maneuvers (30, 50,100, or 300 ml/s) and three established multiple maneuver protocols. We quantify the improved precision with multiple maneuvers and the importance of low flow maneuvers in estimating Caw NO. We conclude by applying the dynamic model to FeNO data from 100 participants of the Southern California Children's Health Study, establishing the feasibility of using the dynamic method to reanalyze archived online FeNO data and extract new information on Caw NO and CA NO in situations where these estimates would have been impossible to obtain using traditional steady-state two compartment model estimation methods.
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Affiliation(s)
- Patrick Muchmore
- Department of Preventive MedicineUniversity of Southern CaliforniaLos AngelesCAUSA
| | - Shujing Xu
- Department of Preventive MedicineUniversity of Southern CaliforniaLos AngelesCAUSA
| | - Paul Marjoram
- Department of Preventive MedicineUniversity of Southern CaliforniaLos AngelesCAUSA
| | - Edward B. Rappaport
- Department of Preventive MedicineUniversity of Southern CaliforniaLos AngelesCAUSA
| | - Jingying Weng
- Department of Preventive MedicineUniversity of Southern CaliforniaLos AngelesCAUSA
| | - Noa Molshatzki
- Department of Preventive MedicineUniversity of Southern CaliforniaLos AngelesCAUSA
| | - Sandrah P. Eckel
- Department of Preventive MedicineUniversity of Southern CaliforniaLos AngelesCAUSA
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15
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Lassmann‐Klee PG, Lehtimäki L, Lindholm T, Malmberg LP, Sovijärvi AR, Piirilä PL. Converting F ENO by different flows to standard flow F ENO. Clin Physiol Funct Imaging 2019; 39:315-321. [PMID: 31058423 PMCID: PMC7003879 DOI: 10.1111/cpf.12574] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 04/30/2019] [Indexed: 12/31/2022]
Abstract
In clinical practice, assessment of expiratory nitric oxide (FENO ) may reveal eosinophilic airway inflammation in asthmatic and other pulmonary diseases. Currently, measuring of FENO is standardized to exhaled flow level of 50 ml s-1 , since the expiratory flow rate affects the FENO results. To enable the comparison of FENO measured with different expiratory flows, we firstly aimed to establish a conversion model to estimate FENO at the standard flow level, and secondly, validate it in five external populations. FENO measurements were obtained from 30 volunteers (mixed adult population) at the following multiple expiratory flow rates: 50, 30, 100 and 300 ml s-1 , after different mouthwash settings, and a conversion model was developed. We tested the conversion model in five populations: healthy adults, healthy children, and patients with COPD, asthma and alveolitis. FENO conversions in the mixed adult population, in healthy adults and in children, showed the lowest deviation between estimatedF ^ ENO from 100 ml s-1 and measured FENO at 50 mL s-1 : -0·28 ppb, -0·44 ppb and 0·27 ppb, respectively. In patients with COPD, asthma and alveolitis, the deviation was -1·16 ppb, -1·68 ppb and 1·47 ppb, respectively. We proposed a valid model to convert FENO in healthy or mixed populations, as well as in subjects with obstructive pulmonary diseases and found it suitable for converting FENO measured with different expiratory flows to the standard flow in large epidemiological data, but not on individual level. In conclusion, a model to convert FENO from different flows to the standard flow was established and validated.
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Affiliation(s)
- Paul G. Lassmann‐Klee
- Unit of Clinical PhysiologyHelsinki University Central Hospital and University of HelsinkiHelsinkiFinland
| | - Lauri Lehtimäki
- Allergy CentreTampere University HospitalFaculty of Medicine and Health TechnologyUniversity of TampereTampereFinland
| | - Tuula Lindholm
- Department of Clinical PhysiologyFinnish Institute of Occupational HealthHelsinkiFinland
| | - Leo Pekka Malmberg
- Laboratory of Clinical PhysiologySkin and Allergy HospitalHelsinki University HospitalHelsinkiFinland
| | - Anssi R.A. Sovijärvi
- Unit of Clinical PhysiologyHelsinki University Central Hospital and University of HelsinkiHelsinkiFinland
| | - Päivi Liisa Piirilä
- Unit of Clinical PhysiologyHelsinki University Central Hospital and University of HelsinkiHelsinkiFinland
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16
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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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17
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Lassmann-Klee PG, Lehtimäki L, Lindholm T, Malmberg LP, Sovijärvi ARA, Piirilä P. Influence of mouthwashes on extended exhaled nitric oxide (F ENO) analysis. Scandinavian Journal of Clinical and Laboratory Investigation 2018; 78:450-455. [PMID: 30345835 DOI: 10.1080/00365513.2018.1497802] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Fractional exhaled nitric oxide (FENO) is used to assess eosinophilic inflammation of the airways. FENO values are influenced by the expiratory flow rate and orally produced NO. We measured FENO at four different expiratory flow levels after two different mouthwashes: tap water and carbonated water. Further, we compared the alveolar NO concentration (CANO), maximum airway NO flux (J'awNO) and airway NO diffusion (DawNO) after these two mouthwashes. FENO was measured in 30 volunteers (healthy or asthmatic) with a chemiluminescence NO-analyser at flow rates of 30, 50, 100 and 300 mL/s. A mouthwash was performed before the measurement at every flow rate. The carbonated water mouthwash significantly reduced FENO compared to the tap water mouthwash at all expiratory flows: 50 mL/s (p < .001), 30 mL/s (p = .001), 100 mL/s (p < .001) and 300 mL/s (p = .004). J'awNO was also significantly reduced (p = .017), however, there were no significant differences in CANO and DawNO. In conclusion, a carbonated water mouthwash can significantly reduce oropharyngeal NO compared to a tap water mouthwash at expiratory flows of 30-300 mL/s without affecting the CANO and DawNO. Therefore, mouthwashes need to be taken into account when comparing FENO results.
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Affiliation(s)
- Paul Guenther Lassmann-Klee
- a Unit of Clinical Physiology, Helsinki University Central Hospital and University of Helsinki , Helsinki , Finland
| | - Lauri Lehtimäki
- b Allergy Centre, Tampere University Hospital and Faculty of Medicine and Life Sciences , University of Tampere , Tampere , Finland
| | - Tuula Lindholm
- c Laboratory of Clinical Physiology , Finnish Institute of Occupational Health , Helsinki , Finland
| | - L Pekka Malmberg
- d Laboratory of Clinical Physiology , Skin and Allergy Hospital , Helsinki , Finland
| | - Anssi Raimo Antero Sovijärvi
- a Unit of Clinical Physiology, Helsinki University Central Hospital and University of Helsinki , Helsinki , Finland
| | - Päivi Piirilä
- a Unit of Clinical Physiology, Helsinki University Central Hospital and University of Helsinki , Helsinki , Finland
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18
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Hoyte FCL, Gross LM, Katial RK. Exhaled Nitric Oxide: An Update. Immunol Allergy Clin North Am 2018; 38:573-585. [PMID: 30342580 DOI: 10.1016/j.iac.2018.06.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Fractional concentration of exhaled nitric oxide (FENO) is a biomarker used to identify allergic airway inflammation. Because it is noninvasive and easy to obtain, its utility has been studied in the diagnosis and management of several respiratory diseases. Much of the research has been done in asthma, and many studies support the use of FENO in aiding diagnosing asthma, predicting steroid responsiveness, and preventing exacerbations by guiding medication dosage and assessing adherence.
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Affiliation(s)
- Flavia C L Hoyte
- Division of Allergy and Immunology, National Jewish Health, 1400 Jackson Street, Denver, CO 80206, USA.
| | - Lara M Gross
- Division of Allergy and Immunology, National Jewish Health, 1400 Jackson Street, Denver, CO 80206, USA; Division of Allergy and Clinical Immunology, Department of Medicine, University of Colorado, 13001 E 17th Place, Aurora, CO 80045, USA
| | - Rohit K Katial
- Division of Allergy and Immunology, National Jewish Health, 1400 Jackson Street, Denver, CO 80206, USA
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19
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Hulo S, Edme JL, Inamo J, Van Bulck R, Dharancy S, Neviere R. Elevated alveolar nitric oxide is linked to poor aerobic capacity and chronotropic incompetence in liver transplant candidates. J Breath Res 2018; 12:046008. [PMID: 30080156 DOI: 10.1088/1752-7163/aad847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND & AIMS Increased nitric oxide is involved in abnormal hemodynamic parameters and respiratory function of cirrhotic patients. We aimed to quantify partitioning exhaled nitric oxide measurements in exhaled air in liver transplantation (LT) candidates and evaluate their relationships with chronotropic incompetence and aerobic capacity. METHODS We compared exhaled nitric oxide (NO) measurements, heart rate response and peak oxygen uptake during incremental exercise in liver transplantation candidates to those of controls. RESULTS As opposed to healthy control subjects, LT candidates displayed elevated alveolar NO, blunted chronotropic response and reduced V'O2 at maximal exercise. In LT candidates, median peak V'O2 was 18.7 ml kg-1 min-1 (interquartile range (IQR) 16.2; 21.8), corresponding to 65% (IQR 57; 72) of the predicted value. Compared with controls, LT candidates had increased levels of alveolar NO (median (IQR) 2.0 (1.2; 2.2) versus 3.1 (2.3; 4.5), p < 0.001). In controls, no relations were found between alveolar NO and V'O2 peak or heart rate reserve whereas in cirrhotic patients, negative correlations and negative slopes were found between alveolar NO and V'O2 peak and heart rate reserve decrease. CONCLUSIONS Increasing alveolar NO could be a specific pathophysiological condition limiting aerobic capacity in LT candidates.
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Affiliation(s)
- S Hulo
- Service d'Explorations Fonctionnelles Respiratoires, Hôpital Calmette, CHU Lille, F-59000, France. Univ. Lille IMPECS IMPact de l'Environnement Chimique sur la Santé humaine, F-59000 Lille, France
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20
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Muchmore P, Rappaport EB, Eckel SP. Bayesian estimation of physiological parameters governing a dynamic two-compartment model of exhaled nitric oxide. Physiol Rep 2018; 5:5/15/e13276. [PMID: 28774947 PMCID: PMC5555880 DOI: 10.14814/phy2.13276] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 04/05/2017] [Indexed: 01/17/2023] Open
Abstract
The fractional concentration of nitric oxide in exhaled breath (feNO) is a biomarker of airway inflammation with applications in clinical asthma management and environmental epidemiology. feNO concentration depends on the expiratory flow rate. Standard feNO is assessed at 50 mL/sec, but “extended NO analysis” uses feNO measured at multiple different flow rates to estimate parameters quantifying proximal and distal sources of NO in the lower respiratory tract. Most approaches to modeling multiple flow feNO assume the concentration of NO throughout the airway has achieved a “steady‐state.” In practice, this assumption demands that subjects maintain sustained flow rate exhalations, during which both feNO and expiratory flow rate must remain constant, and the feNO maneuver is summarized by the average feNO concentration and average flow during a small interval. In this work, we drop the steady‐state assumption in the classic two‐compartment model. Instead, we have developed a new parameter estimation approach based on measuring and adjusting for a continuously varying flow rate over the entire feNO maneuver. We have developed a Bayesian inference framework for the parameters of the partial differential equation underlying this model. Based on multiple flow feNO data from the Southern California Children's Health Study, we use observed and simulated NO concentrations to demonstrate that our approach has reasonable computation time and is consistent with existing steady‐state approaches, while our inferences consistently offer greater precision than current methods.
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Affiliation(s)
- Patrick Muchmore
- Department of Preventive Medicine, University of Southern California, Los Angeles, California
| | - Edward B Rappaport
- Department of Preventive Medicine, University of Southern California, Los Angeles, California
| | - Sandrah P Eckel
- Department of Preventive Medicine, University of Southern California, Los Angeles, California
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21
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Thornadtsson A, Lind A, Weitoft T, Högman M. Altered levels of exhaled nitric oxide in rheumatoid arthritis. Nitric Oxide 2018; 76:1-5. [PMID: 29486306 DOI: 10.1016/j.niox.2018.02.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 01/18/2018] [Accepted: 02/23/2018] [Indexed: 11/18/2022]
Abstract
BACKGROUND Rheumatoid arthritis (RA) is an autoimmune disorder characterized by bone and joint destruction, but other organ systems can also be involved. Recent studies have suggested that the disease may start in the lungs. Exhaled nitric oxide (FENO) is a marker of inflammation. The aims of the study were to compare the NO parameters between subjects with RA and healthy control subjects, and to examine whether the NO parameters correlated with lung function and disease activity in the subjects with RA. METHODS Subjects with RA (n = 35) were recruited during their regular outpatient visits to the rheumatology department. The nitric oxide (NO) parameters: alveolar NO concentration (CANO), airway compartment diffusing capacity of NO (DawNO), and tissue concentration of NO in the airway wall (CawNO), were algorithmically estimated. Healthy subjects (n = 35) matched by age, gender and height were used as controls. Data are given in median, (quartile 25, 75). Wilcoxon Matched Pairs test was used for group comparisons. Mann-Whitney U test was used to make comparisons between any two groups and for pairwise comparisons. Correlations were tested with Spearman rank order correlation. RESULTS CANO was significantly lower in the RA subjects compared with healthy subjects; 1.1 (0.5, 1.8) ppb versus 2.4 (2.0, 3.0) ppb, (p < 0.001). CawNO was significantly lower in the RA subjects with 51 (22, 87) ppb versus 120 (76, 162) ppb in the control group. DawNO was significantly higher at 25 (15, 36) mL/s in the RA group versus the control group's 7.7 (5.3, 10.7) mL/s. CONCLUSIONS There are significant differences between subjects with RA and matched healthy control subjects regarding the exhaled NO parameters. It is unclear if this can be explained by the pathogenesis of RA, consequences of long-term disease, and/or due to drug treatment.
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Affiliation(s)
- Alexandra Thornadtsson
- Department of Medical Sciences, Respiratory, Allergy and Sleep Research, Uppsala University, Uppsala, Sweden; Section of Rheumatology, Centre for Research and Development, Uppsala University/Region Gävleborg, Sweden.
| | - Anders Lind
- Section of Rheumatology, Centre for Research and Development, Uppsala University/Region Gävleborg, Sweden
| | - Tomas Weitoft
- Section of Rheumatology, Centre for Research and Development, Uppsala University/Region Gävleborg, Sweden
| | - Marieann Högman
- Department of Medical Sciences, Respiratory, Allergy and Sleep Research, Uppsala University, Uppsala, Sweden
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Kim YH, Sol IS, Yoon SH, Kim MJ, Kim KW, Sohn MH, Kim KE. Association of extended nitric oxide parameters with bronchial hyperresponsiveness and bronchodilator response in children with asthma. J Breath Res 2017; 11:046003. [PMID: 28656903 DOI: 10.1088/1752-7163/aa7c1f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Theoretical non-linear modeling of exhaled nitric oxide has revealed extended flow-independent parameters that could explain where or how nitric oxide is produced in the lung and transferred to the airway gas stream. We aimed to evaluate the associations of bronchial hyperresponsiveness and bronchodilator response with extended flow-independent nitric oxide parameters. Nitric oxide (30, 50, 100, 200 ml s-1) was measured in 432 children with asthma on the same day with either a methacholine challenge test (n = 156) or spirometry with bronchodilator (n = 276; 96 previously diagnosed with asthma and treated with inhaled corticosteroid, 37 with acute exacerbation treated with systemic corticosteroid). We additionally included 107 healthy controls for evaluation of the suitability of the non-linear model of exhaled nitric oxide. In asthmatic children, the response-dose ratio of the methacholine challenge test was correlated positively with bronchial nitric oxide (JawNO) and airway tissue nitric oxide (CawNO) (r = 0.367 and r = 0.299, respectively; both p < 0.001), while the change in forced expiratory volume in 1 s, representing bronchodilator response, was associated positively with only JawNO (r = 0. 216, p < 0.001). On multiple regression, JawNO, CawNO, and the diffusing capacity of NO (DawNO) were significantly associated with the response-dose ratio. JawNO was significantly associated with change in forced expiratory volume in children with stable asthma but not those with acute exacerbation. Our findings suggest that bronchial hyperresponsiveness is associated with CawNO while factors other than airway tissue inflammation could affect bronchodilator response in children with mild asthma. Systemic corticosteroid use during asthma exacerbation could affect the association of bronchodilator response with extended nitric oxide parameters.
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Affiliation(s)
- Yoon Hee Kim
- Department of Pediatrics, Gangnam Severance Hospital, Institute of Allergy, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
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Karvonen T, Kankaanranta H, Saarelainen S, Moilanen E, Lehtimäki L. Comparison of feasibility and estimates of central and peripheral nitric oxide parameters by different mathematical models. J Breath Res 2017; 11:047102. [DOI: 10.1088/1752-7163/aa7cc0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Molshatski N, Eckel SP. Optimal flow rate sampling designs for studies with extended exhaled nitric oxide analysis. J Breath Res 2017; 11:016012. [PMID: 28104897 DOI: 10.1088/1752-7163/aa5ad0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
INTRODUCTION The fractional concentration of exhaled nitric oxide (FeNO) is a biomarker of airway inflammation. Repeat FeNO maneuvers at multiple fixed exhalation flow rates (extended NO analysis) can be used to estimate parameters quantifying proximal and distal sources of NO in mathematical models of lower respiratory tract NO. A growing number of studies use extended NO analysis, but there is no official standard flow rate sampling protocol. In this paper, we provide information for study planning by deriving theoretically optimal flow rate sampling designs. METHODS First, we reviewed previously published designs. Then, under a nonlinear regression framework for estimating NO parameters in the steady-state two compartment model of NO, we identified unbiased optimal four flow rate designs (within the range of 10-400 ml s-1) using theoretical derivations and simulation studies. Optimality criteria included NO parameter standard errors (SEs). A simulation study was used to estimate sample sizes required to detect associations with NO parameters estimated from studies with different designs. RESULTS Most designs (77%) were unbiased. NO parameter SEs were smaller for designs with: more target flows, more replicate maneuvers per target flow, and a larger range of target flows. High flows were most important for estimating alveolar NO concentration, while low flows were most important for the proximal NO parameters. The Southern California Children's Health Study design (30, 50, 100 and 300 ml s-1) had ≥1.8 fold larger SEs and required 1.1-3.2 fold more subjects to detect the association of a determinant with each NO parameter as compared to an optimal design of 10, 50, 100 and 400 ml s-1. CONCLUSIONS There is a class of reasonable flow rate sampling designs with good theoretical performance. In practice, designs should be selected to balance the tradeoffs between optimality and feasibility of the flow range and total number of maneuvers.
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Affiliation(s)
- Noa Molshatski
- Department of Preventive Medicine, University of Southern California, Los Angeles, CA, United States of America
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Kozij NK, Granton JT, Silkoff PE, Thenganatt J, Chakravorty S, Johnson SR. Exhaled Nitric Oxide in Systemic Sclerosis Lung Disease. Can Respir J 2017; 2017:6736239. [PMID: 28293128 PMCID: PMC5331166 DOI: 10.1155/2017/6736239] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 12/09/2016] [Accepted: 01/09/2017] [Indexed: 11/17/2022] Open
Abstract
Background. Exhaled nitric oxide (eNO) is a potential biomarker to distinguish systemic sclerosis (SSc) associated pulmonary arterial hypertension (PAH) and interstitial lung disease (ILD). We evaluated the discriminative validity, feasibility, methods of eNO measurement, and magnitude of differences across lung diseases, disease-subsets (SSc, systemic lupus erythematosus), and healthy-controls. Methods. Consecutive subjects in the UHN Pulmonary Hypertension Programme were recruited. Exhaled nitric oxide was measured at 50 mL/s intervals using chemiluminescent detection. Alveolar and conducting airway NO were partitioned using a two-compartment model of axial diffusion (CMAD) and the trumpet model of axial diffusion (TMAD). Results. Sixty subjects were evaluated. Using the CMAD model, control subjects had lower median (IQR) alveolar NO than all PAH subjects (2.0 (1.5, 2.5) versus 3.14 ppb (2.3, 4.0), p = 0.008). SSc-ILD had significantly lower median conducting airway NO compared to controls (1009.5 versus 1342.1 ml⁎ppb/s, p = 0.04). SSc-PAH had increased median (IQR) alveolar NO compared to controls (3.3 (3.0, 5.7) versus 2.0 ppb (1.5, 2.5), p = 0.01). SSc-PAH conducting airway NO inversely correlated with DLCO (r -0.88 (95% CI -0.99, -0.26)). Conclusion. We have demonstrated feasibility, identified that CMAD modeling is preferred in SSc, and reported the magnitude of differences across cases and controls. Our data supports discriminative validity of eNO in SSc lung disease.
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Affiliation(s)
- Natalie K. Kozij
- University Health Network Pulmonary Hypertension Programme, Toronto General Hospital, Department of Medicine, University of Toronto, Toronto, ON, Canada
| | - John T. Granton
- University Health Network Pulmonary Hypertension Programme, Toronto General Hospital, Department of Medicine, University of Toronto, Toronto, ON, Canada
| | | | - John Thenganatt
- University Health Network Pulmonary Hypertension Programme, Toronto General Hospital, Department of Medicine, University of Toronto, Toronto, ON, Canada
| | - Shobha Chakravorty
- University Health Network Pulmonary Hypertension Programme, Toronto General Hospital, Toronto, ON, Canada
| | - Sindhu R. Johnson
- University Health Network Pulmonary Hypertension Programme, Toronto General Hospital, Toronto Scleroderma Program, Toronto Western Hospital, Mount Sinai Hospital, Department of Medicine, Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, ON, Canada
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Högman M, Lehtimäki L, Dinh-Xuan AT. Utilising exhaled nitric oxide information to enhance diagnosis and therapy of respiratory disease - current evidence for clinical practice and proposals to improve the methodology. Expert Rev Respir Med 2017; 11:101-109. [PMID: 28076986 DOI: 10.1080/17476348.2017.1281746] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
INTRODUCTION A non-invasive tool to diagnose respiratory diseases and to follow treatment has long been looked-for. Exhaled nitric oxide (NO) is a promising marker of inflammation in asthma but nearly 25-years of research has shown that it works in only certain endotypes of asthma. The modelling of NO dynamics of the lung can give more information than a single FENO value. Areas covered: The estimation of the NO production in the conducting airways and in the gas exchange area has given new insight of the NO production in diseases beyond asthma. In this article, we discuss the importance of methodology for NO measurement in the exhaled breath and the indication of applying this technique to detect respiratory disorders. This narrative review is an attempt to examine and discuss the physiological basis underlying exhaled NO measurements and the clinical evidence of the usefulness of this method in asthma and various other respiratory disorders. Expert commentary: Estimation of the NO parameters would aid in our understanding of the NO dynamics of the lung and thereby give more knowledge how to interpret the measured FENO value in clinical practice.
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Affiliation(s)
- Marieann Högman
- a Department of Medical Sciences, Lung- Allergy- and Sleep Research , Uppsala University , Uppsala , Sweden
| | - Lauri Lehtimäki
- b Allergy Centre , Tampere University Hospital , Tampere , Finland.,c Medical School , University of Tampere , Tampere , Finland
| | - Anh Tuan Dinh-Xuan
- d Department of Respiratory Physiology , Cochin Hospital & Paris Descartes University , Paris , France
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Abstract
Research over the past 30 years has identified mechanistic biochemical oxidation pathways that contribute to asthma pathophysiology. Redox imbalance is present in asthma and strongly linked to the pathobiology of airflow obstruction, airway hyperreactivity, and remodeling. High levels of reactive oxygen species, reactive nitrogen species, and oxidatively modified proteins in the lung, blood, and urine provide conclusive evidence for pathologic oxidation in asthma. Concurrent loss of antioxidants, such as superoxide dismutases and catalase, is attributed to redox modifications of the enzymes, and further amplifies the oxidative injury in the airway. The presence of high levels of urine bromotyrosine, an oxidation product of eosinophil peroxidase, identifies activated eosinophils, and shows promise for use as a noninvasive biomarker of poor asthma control.
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Dhawale VS, Amara VR, Karpe PA, Malek V, Patel D, Tikoo K. Activation of angiotensin-converting enzyme 2 (ACE2) attenuates allergic airway inflammation in rat asthma model. Toxicol Appl Pharmacol 2016; 306:17-26. [PMID: 27343405 DOI: 10.1016/j.taap.2016.06.026] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 06/21/2016] [Indexed: 02/07/2023]
Abstract
Angiotensin-I converting enzyme (ACE) is positively correlated to asthma, chronic obstructive pulmonary disease (COPD), acute respiratory distress syndrome (ARDS) and is highly expressed in lungs. ACE2, the counteracting enzyme of ACE, was proven to be protective in pulmonary, cardiovascular diseases. In the present study we checked the effect of ACE2 activation in animal model of asthma. Asthma was induced in male wistar rats by sensitization and challenge with ovalbumin and then treated with ACE2 activator, diminazene aceturate (DIZE) for 2weeks. 48h after last allergen challenge, animals were anesthetized, blood, BALF, femoral bone marrow lavage were collected for leucocyte count; trachea for measuring airway responsiveness to carbachol; lungs and heart were isolated for histological studies and western blotting. In our animal model, the characteristic features of asthma such as altered airway responsiveness to carbachol, eosinophilia and neutrophilia were observed. Western blotting revealed the increased pulmonary expression of ACE1, IL-1β, IL-4, NF-κB, BCL2, p-AKT, p-p38 and decreased expression of ACE2 and IκB. DIZE treatment prevented these alterations. Intraalveolar interstitial thickening, inflammatory cell infiltration, interstitial fibrosis, oxidative stress and right ventricular hypertrophy in asthma control animals were also reversed by DIZE treatment. Activation of ACE2 by DIZE conferred protection against asthma as evident from biochemical, functional, histological and molecular parameters. To the best of our knowledge, we report for the first time that activation of ACE2 by DIZE prevents asthma progression by altering AKT, p38, NF-κB and other inflammatory markers.
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Affiliation(s)
- Vaibhav Shrirang Dhawale
- Laboratory of Epigenetics and Diseases, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S Nagar, Punjab 160062, India
| | - Venkateswara Rao Amara
- Laboratory of Epigenetics and Diseases, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S Nagar, Punjab 160062, India
| | - Pinakin Arun Karpe
- Laboratory of Epigenetics and Diseases, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S Nagar, Punjab 160062, India
| | - Vajir Malek
- Laboratory of Epigenetics and Diseases, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S Nagar, Punjab 160062, India
| | - Deep Patel
- Laboratory of Epigenetics and Diseases, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S Nagar, Punjab 160062, India
| | - Kulbhushan Tikoo
- Laboratory of Epigenetics and Diseases, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S Nagar, Punjab 160062, India..
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Soluble guanylate cyclase as an alternative target for bronchodilator therapy in asthma. Proc Natl Acad Sci U S A 2016; 113:E2355-62. [PMID: 27071111 DOI: 10.1073/pnas.1524398113] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Asthma is defined by airway inflammation and hyperresponsiveness, and contributes to morbidity and mortality worldwide. Although bronchodilation is a cornerstone of treatment, current bronchodilators become ineffective with worsening asthma severity. We investigated an alternative pathway that involves activating the airway smooth muscle enzyme, soluble guanylate cyclase (sGC). Activating sGC by its natural stimulant nitric oxide (NO), or by pharmacologic sGC agonists BAY 41-2272 and BAY 60-2770, triggered bronchodilation in normal human lung slices and in mouse airways. Both BAY 41-2272 and BAY 60-2770 reversed airway hyperresponsiveness in mice with allergic asthma and restored normal lung function. The sGC from mouse asthmatic lungs displayed three hallmarks of oxidative damage that render it NO-insensitive, and identical changes to sGC occurred in human lung slices or in human airway smooth muscle cells when given chronic NO exposure to mimic the high NO in asthmatic lung. Our findings show how allergic inflammation in asthma may impede NO-based bronchodilation, and reveal that pharmacologic sGC agonists can achieve bronchodilation despite this loss.
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Thornadtsson A, Neerincx AH, Högman M, Hugen C, Sintnicolaas C, Harren FJM, Merkus PJFM, Cristescu SM. Extended nitric oxide analysis may improve personalized anti-inflammatory treatment in asthmatic children with intermediate F(E)NO50. J Breath Res 2015; 9:047114. [PMID: 26670199 DOI: 10.1088/1752-7155/9/4/047114] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Exhaled nitric oxide (F(E)NO) is elevated in asthma, and a clinical practice guideline has been published with recommendations for anti-inflammatory treatment. It summarizes that a F(E)NO at an expiratory flow rate of 50 ml s(-1) (F(E)NO50) above 35 ppb in children indicates eosinophilic inflammation, and the most likely response is to use inhaled corticosteroids. Intermediate F(E)NO50 between 20-35 ppb should be interpreted cautiously. The aim of the study was to investigate this guideline in a small group of asthmatic children. Thirty-seven asthmatic children; 23 boys and 14 girls, visited the outpatient clinic, and provided exhaled breath samples for offline NO measurement. These samples were analysed with chemiluminescence techniques. Three flow rates, namely 16, 90 and 230 ml s(-1) were used for the extended NO analysis (Högman-Meriläinen algorithm, HMA) to estimate the alveolar concentration (C(A)NO), diffusion rate of the airway wall (D(aw)NO) and airway wall content (C(aw)NO). For accuracy of the HMA, the estimated value of F(E)NO at 50 ml s(-1) (F(E)NO50) was compared with measured F(E)NO50. In nine children the difference was more than 5 ppb and the data were therefore excluded. Five children with F(E)NO50 <20 ppb had no known allergy and their F(E)NO50 geometrical mean (25th; 75th percentile) was 11 (10;14) and CawNO was 32 (20;43) ppb. Ten children with F(E)NO50 > 35 ppb had an allergy and had F(E)NO50 of 56 (47;60) ppb and C(aw)NO of 140 (121;172) ppb. Thirteen children with allergies, with intermediate F(E)NO50, had F(E)NO50 of 27 (25;30) ppb with a wide range of C(aw)NO. In five of these children, values were comparable to healthy children, 44 (43;50) ppb while eight children had elevated C(aw)NO values of 108 (95;129) ppb. Our data indicate the clinical potential use of extended NO analysis to determine the personal target value of F(E)NO50 for monitoring the treatment outcome. Furthermore, for children with intermediate F(E)NO50 more than half of them could possibly benefit from an adjustment of inhaled corticosteroids if the C(aw)NO value was considered.
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Affiliation(s)
- A Thornadtsson
- Respiratory, Allergy and Sleep Research, Department of Medical Sciences, Uppsala University, Uppsala, Sweden. Centre for Clinical Research, Uppsala University/Region Gävleborg, Uppsala, Sweden
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Larsson-Callerfelt AK, Weitoft M, Nihlberg K, Bjermer L, Westergren-Thorsson G, Tufvesson E. iNOS affects matrix production in distal lung fibroblasts from patients with mild asthma. Pulm Pharmacol Ther 2015; 34:64-71. [PMID: 26362859 DOI: 10.1016/j.pupt.2015.09.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Revised: 08/24/2015] [Accepted: 09/06/2015] [Indexed: 02/07/2023]
Abstract
INTRODUCTION A high level of exhaled nitric oxide (NO) is a marker for inflammation in the airways of asthmatic subjects. However, little is known about how NO and inducible nitric oxides synthase (iNOS) activity may affect remodelling in the distal lung. We hypothesized that there is a link between iNOS and ongoing remodelling processes in the distal lung of mild asthmatics. METHODS Patients with mild asthma (n = 6) and healthy control subjects (n = 8) were included. Exhaled NO was measured at different flow rates and alveolar NO concentrations were calculated. For studies of remodelling processes in the distal lung, primary fibroblasts were grown from transbronchial biopsies and stimulated with unselective and selective NOS inhibitors or a NO donor. The mRNA expression of iNOS and synthesis of NO (indirectly as nitrite/nitrate) were measured and distal lung fibroblast synthesis of the extracellular matrix proteoglycans were analysed. RESULTS The distal lung fibroblasts expressed iNOS, and there was a tendency of higher expression in fibroblasts from patients with asthma. The selective iNOS inhibitor 1400 W inhibited iNOS expression and NO synthesis in fibroblasts from patients with asthma (p = 0.031). Treatment with 1400 W significantly increased synthesis of the proteoglycan versican (p = 0.018) in distal fibroblasts from patients with asthma whereas there were no effects in fibroblasts from control subjects. CONCLUSIONS Our data suggest that there is a link between iNOS and remodelling in the distal lung of subjects with mild asthma and that iNOS could have a modulatory role in pathological airway remodelling.
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Affiliation(s)
| | - Maria Weitoft
- Lung Biology, Department of Experimental Medical Sciences, Lund University, Lund, Sweden.
| | - Kristian Nihlberg
- Lung Biology, Department of Experimental Medical Sciences, Lund University, Lund, Sweden.
| | - Leif Bjermer
- Respiratory Medicine and Allergology, Department of Clinical Sciences Lund, Lund University, Lund, Sweden.
| | | | - Ellen Tufvesson
- Respiratory Medicine and Allergology, Department of Clinical Sciences Lund, Lund University, Lund, Sweden.
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Corcuera-Elosegui P, Sardón-Prado O, Aldasoro-Ruiz A, Korta-Murua J, Mintegui-Aramburu J, Emparanza-Knorr JI, Pérez-Yarza EG. Inflammatory Patterns in Asthmatic Children Based on Alveolar Nitric Oxide Determination. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.arbr.2015.02.032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Fractional Exhaled Nitric Oxide: Indications and Interpretation. DIAGNOSTIC TESTS IN PEDIATRIC PULMONOLOGY 2015. [DOI: 10.1007/978-1-4939-1801-0_14] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Corcuera-Elosegui P, Sardón-Prado O, Aldasoro-Ruiz A, Korta-Murua J, Mintegui-Aramburu J, Emparanza-Knorr JI, Pérez-Yarza EG. Inflammatory patterns in asthmatic children based on alveolar nitric oxide determination. Arch Bronconeumol 2014; 51:279-84. [PMID: 25311845 DOI: 10.1016/j.arbres.2014.07.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2014] [Revised: 06/18/2014] [Accepted: 07/01/2014] [Indexed: 11/18/2022]
Abstract
INTRODUCTION Nitric oxide (NO) levels can be measured at proximal (maximum airway NO flux [J'aw(NO)]) and distal (alveolar NO concentration [C(ANO)]) levels. Four inflammatory patterns have been described in asthmatic individuals, although their relevance has not been well established. The objective was to determine J'aw(NO) and C(ANO) in order to establish four inflammatory categories in asthmatics. MATERIAL AND METHODS Cross-sectional study of a sample consisting of healthy and asthmatic children. Exhaled NO was determined at multiple flows. J'aw(NO) and C(ANO) were obtained according to the two-compartment model. The asthma control questionnaire (ACQ) and spirometry were administered to asthmatic children. Patients were categorized as type I (normal J'aw(NO) and C(ANO)), type II (elevated J'aw(NO) and normal C(ANO)), type III (elevated J'aw(NO) and C(ANO)) and type IV (normal J'aw(NO) and elevated C(ANO)). Correlation between FE(NO,50), J'aw(NO) and C(ANO) was analyzed using Spearman's R Correlation Test. Analysis of variance and paired comparisons were performed using the Bonferroni correction. RESULTS One hundred sixty-two children were studied, of whom 49 (32.23%) were healthy controls and 103 (67.76%) asthmatics. In the control subjects, FE(NO,50) (ppb)(median and range) was 11.5 (1.6 to 27.3), J'aw(NO) (pl/s) was 516 (98.3 to 1470) and C(ANO) (ppb) was 2.2 (0.1 to 4.5). Forty-four (42.7%) of the asthmatic participants were categorized as type I, 41 (39.8%) as type II, 14 (13.5%) as type III and 4 (3.88%) as type IV. Good correlation was observed between J'aw(NO) and FE(NO,50) (r=0.97). There was no association between J'aw(NO) and C(ANO). FEV1/FVC decreased significantly in type III (mean 79.8±7.5). Morbidity was significantly higher in types III and IV. CONCLUSIONS Normal values obtained are similar to those previously reported. Asthmatics with high C(ANO) showed higher morbidity. No correlation was found between proximal and distal inflammation.
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Affiliation(s)
- Paula Corcuera-Elosegui
- Sección de Neumología Infantil, Hospital Universitario Donostia, San Sebastián, Guipúzcoa, España
| | - Olaia Sardón-Prado
- Sección de Neumología Infantil, Hospital Universitario Donostia, San Sebastián, Guipúzcoa, España; Departamento de Pediatría, Universidad del País Vasco (UPV/EHU), San Sebastián, Guipúzcoa, España.
| | - Ane Aldasoro-Ruiz
- Sección de Neumología Infantil, Hospital Universitario Donostia, San Sebastián, Guipúzcoa, España
| | - Javier Korta-Murua
- Sección de Neumología Infantil, Hospital Universitario Donostia, San Sebastián, Guipúzcoa, España; Departamento de Pediatría, Universidad del País Vasco (UPV/EHU), San Sebastián, Guipúzcoa, España
| | - Javier Mintegui-Aramburu
- Sección de Neumología Infantil, Hospital Universitario Donostia, San Sebastián, Guipúzcoa, España
| | - José I Emparanza-Knorr
- Unidad de Epidemiología (CIBER-ESP), Hospital Universitario Donostia, San Sebastián, Guipúzcoa, España
| | - Eduardo G Pérez-Yarza
- Sección de Neumología Infantil, Hospital Universitario Donostia, San Sebastián, Guipúzcoa, España; Departamento de Pediatría, Universidad del País Vasco (UPV/EHU), San Sebastián, Guipúzcoa, España; Centro de Investigación Biomédica en Red, Enfermedades Respiratorias (CIBERES), San Sebastián, Guipúzcoa, España
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Sardón O, Corcuera P, Aldasoro A, Korta J, Mintegui J, Emparanza JI, Pérez-Yarza EG. Alveolar nitric oxide and its role in pediatric asthma control assessment. BMC Pulm Med 2014; 14:126. [PMID: 25090994 PMCID: PMC4124482 DOI: 10.1186/1471-2466-14-126] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 07/29/2014] [Indexed: 11/17/2022] Open
Abstract
Background Nitric oxide can be measured at multiple flow rates to determine proximal (maximum airway nitric oxide flux; JawNO) and distal inflammation (alveolar nitric oxide concentration; CANO). The main aim was to study the association among symptoms, lung function, proximal (maximum airway nitric oxide flux) and distal (alveolar nitric oxide concentration) airway inflammation in asthmatic children treated and not treated with inhaled glucocorticoids. Methods A cross-sectional study with prospective data collection was carried out in a consecutive sample of girls and boys aged between 6 and 16 years with a medical diagnosis of asthma. Maximum airway nitric oxide flux and alveolar nitric oxide concentration were calculated according to the two-compartment model. In asthmatic patients, the asthma control questionnaire (CAN) was completed and forced spirometry was performed. In controls, differences between the sexes in alveolar nitric oxide concentration and maximum airway nitric oxide flux and their correlation with height were studied. The correlation among the fraction of exhaled NO at 50 ml/s (FENO50), CANO, JawNO, forced expiratory volume in 1 second (FEV1) and the CAN questionnaire was measured and the degree of agreement regarding asthma control assessment was studied using Cohen’s kappa. Results We studied 162 children; 49 healthy (group 1), 23 asthmatic participants without treatment (group 2) and 80 asthmatic patients treated with inhaled corticosteroids (group 3). CANO (ppb) was 2.2 (0.1-4.5), 3 (0.2-9.2) and 2.45 (0.1-24), respectively. JawNO (pl/s) was 516 (98.3-1470), 2356.67 (120–6110) and 1426 (156–11805), respectively. There was a strong association (r = 0.97) between FENO50 and JawNO and the degree of agreement was very good in group 2 and was good in group 3. There was no agreement or only slight agreement between the measures used to monitor asthma control (FEV1, CAN questionnaire, CANO and JawNO). Conclusions The results for CANO and JawNO in controls were similar to those found in other reports. There was no agreement or only slight agreement among the three measure instruments analyzed to assess asthma control. In our sample, no additional information was provided by CANO and JawNO.
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Affiliation(s)
- Olaia Sardón
- Division of Pediatric Respiratory Medicine, Hospital Universitario Donostia, Avda, Dr, Beguiristain número 118, San Sebastian, Guipúzcoa CP 20014, Spain.
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Högman M, Thornadtsson A, Hedenstierna G, Meriläinen P. A practical approach to the theoretical models to calculate NO parameters of the respiratory system. J Breath Res 2014; 8:016002. [PMID: 24565997 DOI: 10.1088/1752-7155/8/1/016002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Expired nitric oxide (NO) is used as a biomarker in different respiratory diseases. The recommended flow rate of 50 mL s⁻¹ (F(E)NO₀.₀₅) does not reveal from where in the lung NO production originated. Theoretical models of NO transfer from the respiratory system, linear or nonlinear approaches, have therefore been developed and applied. These models can estimate NO from distal lung (alveolar NO) and airways (bronchial flux). The aim of this study was to show the limitation in exhaled flow rate for the theoretical models of NO production in the respiratory system, linear and nonlinear models. Subjects (n = 32) exhaled at eight different flow rates between 10-350 mL s⁻¹ for the theoretical protocols. Additional subjects (n = 32) exhaled at tree flow rates (20, 100 and 350 mL s⁻¹) for the clinical protocol. When alveolar NO is calculated using high flow rates with the linear model, correction for axial back diffusion becomes negligible, -0.04 ppb and bronchial flux enhanced by 1.27. With Högman and Meriläinen algorithm (nonlinear model) the corrections factors can be understood to be embedded, and the flow rates to be used are ≤20, 100 and ≥350 mL s⁻¹. Applying these flow rates in a clinical setting any F(E)NO can be calculated necessitating fewer exhalations. Hence, measured F(E)NO₀.₀₅ 12.9 (7.2-18.7) ppb and calculated 12.9 (6.8-18.7) ppb. In conclusion, the only possibility to avoid inconsistencies between research groups is to use the measured NO values as such in modelling, and apply tight quality control to accuracies in both NO concentration and exhaled flow measurements.
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Affiliation(s)
- M Högman
- Centre for Research and Development, Uppsala University/County Council of Gävleborg, SE 801 88 Gävle, Sweden. Department of Medical Sciences, Lung Medicine and Allergology, Uppsala University, Sweden
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Eckel SP, Linn WS, Berhane K, Rappaport EB, Salam MT, Zhang Y, Gilliland FD. Estimation of parameters in the two-compartment model for exhaled nitric oxide. PLoS One 2014; 9:e85471. [PMID: 24465571 PMCID: PMC3894971 DOI: 10.1371/journal.pone.0085471] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 11/27/2013] [Indexed: 01/13/2023] Open
Abstract
The fractional concentration of exhaled nitric oxide (FeNO) is a biomarker of airway inflammation that is being increasingly considered in clinical, occupational, and epidemiological applications ranging from asthma management to the detection of air pollution health effects. FeNO depends strongly on exhalation flow rate. This dependency has allowed for the development of mathematical models whose parameters quantify airway and alveolar compartment contributions to FeNO. Numerous methods have been proposed to estimate these parameters using FeNO measured at multiple flow rates. These methods—which allow for non-invasive assessment of localized airway inflammation—have the potential to provide important insights on inflammatory mechanisms. However, different estimation methods produce different results and a serious barrier to progress in this field is the lack of a single recommended method. With the goal of resolving this methodological problem, we have developed a unifying framework in which to present a comprehensive set of existing and novel statistical methods for estimating parameters in the simple two-compartment model. We compared statistical properties of the estimators in simulation studies and investigated model fit and parameter estimate sensitivity across methods using data from 1507 schoolchildren from the Southern California Children's Health Study, one of the largest multiple flow FeNO studies to date. We recommend a novel nonlinear least squares model with natural log transformation on both sides that produced estimators with good properties, satisfied model assumptions, and fit the Children's Health Study data well.
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Affiliation(s)
- Sandrah P. Eckel
- Department of Preventive Medicine, University of Southern California, Los Angeles, California, United States of America
- * E-mail:
| | - William S. Linn
- Department of Preventive Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Kiros Berhane
- Department of Preventive Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Edward B. Rappaport
- Department of Preventive Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Muhammad T. Salam
- Department of Preventive Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Yue Zhang
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, United States of America
| | - Frank D. Gilliland
- Department of Preventive Medicine, University of Southern California, Los Angeles, California, United States of America
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Abstract
During inspiration and expiration, gases traverse the conducting airways as they are transported between the environment and the alveolar region of the lungs. The term "conducting" airways is used broadly as the airway tree is thought largely to provide a conduit for the respiratory gases, oxygen and carbon dioxide. However, despite a significantly smaller surface area, and thicker barrier separating the gas phase from the blood when compared to the alveolar region, the airway tree can participate in gas exchange under special conditions such as high water solubility, high chemical reactivity, or production of the gas within the airway wall tissue. While these conditions do not apply to the respiratory gases, other gases demonstrate substantial exchange of the airways and are of particular importance to the inflammatory response of the lungs, the medical-legal field, occupational health, metabolic disorders, or protection of the delicate alveolar membrane. Given the significant structural differences between the airways and the alveolar region, the physical determinants that control airway gas exchange are unique and require different models (both experimental and mathematical) to explore. Our improved physiological understanding of airway gas exchange combined with improved analytical methods to detect trace compounds in the exhaled breath provides future opportunities to develop new exhaled biomarkers that are characteristic of pulmonary and systemic conditions.
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Affiliation(s)
- Steven C George
- Department of Biomedical Engineering, University of California, Irvine, California, USA.
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Cattoni I, Guarnieri G, Tosetto A, Mason P, Scarpa MC, Saetta M, Maestrelli P. Mechanisms of decrease in fractional exhaled nitric oxide during acute bronchoconstriction. Chest 2013; 143:1269-1276. [PMID: 23370456 DOI: 10.1378/chest.12-1374] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND Fractional exhaled nitric oxide measured at expiratory flow of 50 mL/s (Feno50), a biomarker of airway inflammation, is affected by changes in airway caliber. Whether a lower Feno50 level during bronchoconstriction is only an artifact due to the strong flow dependence of this parameter is controversial. METHODS We aimed to evaluate the dynamics of airway and alveolar nitric oxide (NO) during acute bronchoconstriction induced by methacholine. Exhaled NO was measured at expiratory flows of 10, 50, 100, 150, and 250 mL/s before and after metacholine in 26 responders to methacholine and 37 nonresponders. Flow-independent parameters (airway wall NO flux, airway NO diffusing capacity, airway wall NO concentration, alveolar NO concentration) were calculated using a two-compartment model, and correction for NO axial back diffusion was applied. RESULTS Bronchoconstriction in responders was associated with a decrease in Feno50 (-28%, P < .0001), in airway wall NO flux (-34%, P < .0001), and in airway NO diffusing capacity (-15%, P < .05). In contrast, alveolar NO concentration was not affected by bronchoconstriction. Postmethacholine changes in Feno50 were more strictly related to the ventilation distribution, assessed by single-breath carbon monoxide uptake, than to larger airways caliber, assessed by FEV1. When bronchoconstriction was reversed by salbutamol, airway wall NO flux and airway NO diffusing capacity returned to values comparable to those measured premethacholine. CONCLUSIONS The changes in airway caliber induced by noninflammatory stimuli alter NO transport in the lung. The changes in NO dynamics are limited to conductive airways and are characterized by a reduction of NO flow to luminal space.
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Affiliation(s)
- Ilaria Cattoni
- Department of Cardiologic, Thoracic and Vascular Sciences, University of Padova, Padova, Italy
| | - Gabriella Guarnieri
- Department of Cardiologic, Thoracic and Vascular Sciences, University of Padova, Padova, Italy
| | - Alessandro Tosetto
- Department of Cardiologic, Thoracic and Vascular Sciences, University of Padova, Padova, Italy
| | - Paola Mason
- Department of Cardiologic, Thoracic and Vascular Sciences, University of Padova, Padova, Italy
| | - Maria C Scarpa
- Department of Cardiologic, Thoracic and Vascular Sciences, University of Padova, Padova, Italy
| | - Marina Saetta
- Department of Cardiologic, Thoracic and Vascular Sciences, University of Padova, Padova, Italy
| | - Piero Maestrelli
- Department of Cardiologic, Thoracic and Vascular Sciences, University of Padova, Padova, Italy.
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Pyrgos G, Togias A, Brown RH. Phosphodiesterase V inhibition reduces airway responsiveness, but does not improve the beneficial effect of deep inspiration. ACTA ACUST UNITED AC 2013; 86:243-51. [PMID: 23860331 DOI: 10.1159/000350451] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Accepted: 02/26/2013] [Indexed: 11/19/2022]
Abstract
BACKGROUND Deep inspirations (DIs) can prevent (bronchoprotection; BP) and reverse (bronchodilation; BD) methacholine (Mch)-induced bronchoconstriction, but this effect is reduced or absent in people with asthma or airways hyperresponsiveness (AHR). The mechanisms of this defect are unknown. OBJECTIVE To indirectly examine the role of guanosine 3',5'-cyclic monophosphate (cGMP) by testing the hypothesis that the phosphodiesterase (PDE) V inhibitor, sildenafil, would improve DI-induced BP in individuals with AHR. METHODS Thirty-two individuals were screened and 15 met all the inclusion/exclusion criteria (7 subjects with AHR and 8 healthy subjects). A single-dose Mch challenge inducing a 20% reduction in FEV1 in the absence of DIs was first identified. Thereafter, every study participant had 4 pairs of visits, each pair testing DI-induced BP and BD against the single-dose Mch, with no drug, or pretreatment with 25, 50 and 100 mg of sildenafil, respectively, in consecutive order. RESULTS Sildenafil did not influence baseline lung function. However, in the absence of DIs, the drug caused a dose-dependent attenuation of the Mch-induced decrease in FEV1 by 17% (median value; 25th percentile: 1, 75th percentile: 16), 35% (-3, 61) and 37% (13, 79) for the 25-, 50- and 100-mg doses, respectively (p = 0.0004). No differences between the two participant groups were found. There were no effects of sildenafil on DI-induced BP or BD. CONCLUSION We infer from these results that the mechanism responsible for the defective ability of DIs to protect the airways from bronchoconstriction is unlikely to be due to dysregulation of cGMP. Of importance, a potential role for PDE V inhibition as a bronchoprotector treatment needs to be explored.
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Affiliation(s)
- George Pyrgos
- Department of Medicine, Division of Allergy and Clinical Immunology, Baltimore, Md., USA
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Högman M, Meriläinen P. Guidance for a personal target value of F(E)NO in allergic asthma: case report and theoretical example. Ups J Med Sci 2013; 118:59-61. [PMID: 22793785 PMCID: PMC3572674 DOI: 10.3109/03009734.2012.704433] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
In clinically stable asthma the exhaled NO values (F(E)NO) are generally higher than in control subjects. Therefore, reference values are of limited importance in clinical practice. This is demonstrated in this case report, but it is also shown that NO parameters from non-linear modelling do have a clinical value. A subject with asthma was treated with inhaled corticosteroids for 1 week. The non-linear NO model was used to measure the response to treatment. The NO parameters from subjects with atopic rhinitis and asthma were fed into a computer program to generate theoretical F(E)NO₀.₀₅ values, i.e. target values. There was a dramatic decrease in F(E)NO₀.₀₅ due to treatment, from 82 to 34 ppb, but it remained higher than in healthy controls. This is due to the elevated diffusion rate of NO, unchanged by treatment. When the NO parameters are known, a personal best value of F(E)NO₀.₀₅ (fractional concentration of exhaled NO in the gas phase, 0.05 L/s) can be calculated, which can be the target value when only F(E)NO₀.₀₅ can be monitored. In conclusion, reference values for NO parameters are shown to be clinically useful. It is essential that every patient receives his/her target value of F(E)NO₀.₀₅, when only a single NO measurement is available. In our opinion, this is the reason why there are few successful studies of trying to target the NO value with inhaled corticosteroids.
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Affiliation(s)
- Marieann Högman
- Respiratory Medicine and Allergology, Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
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Cristescu SM, Mandon J, Harren FJM, Meriläinen P, Högman M. Methods of NO detection in exhaled breath. J Breath Res 2013; 7:017104. [PMID: 23445766 DOI: 10.1088/1752-7155/7/1/017104] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
There is still an unexplored potential for exhaled nitric oxide (NO) in many clinical applications. This study presents an overview of the currently available methods for monitoring NO in exhaled breath and the use of the modelling of NO production and transport in the lung in clinical practice. Three technologies are described, namely chemiluminescence, electrochemical sensing and laser-based detection with their advantages and limitations. Comparisons are made in terms of sensitivity, time response, size, costs and suitability for clinical purposes. The importance of the flow rate for NO sampling is discussed from the perspective of the recent recommendations for standardized procedures for online and offline NO measurement. The measurement of NO at one flow rate, such as 50 ml s(-1), can neither determine the alveolar site/peripheral contribution nor quantify the difference in NO diffusion from the airways walls. The use of NO modelling (linear or non-linear approach) can solve this problem and provide useful information about the source of NO. This is of great value in diagnostic procedures of respiratory diseases and in treatment with anti-inflammatory drugs.
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Affiliation(s)
- S M Cristescu
- Life Science Trace Gas Facility, Molecular and Laser Physics, Institute for Molecules and Materials, Radboud University, Nijmegen, The Netherlands.
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Walker WT, Liew A, Harris A, Cole J, Lucas JS. Upper and lower airway nitric oxide levels in primary ciliary dyskinesia, cystic fibrosis and asthma. Respir Med 2013; 107:380-6. [PMID: 23290188 DOI: 10.1016/j.rmed.2012.11.021] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Revised: 11/26/2012] [Accepted: 11/28/2012] [Indexed: 10/27/2022]
Abstract
BACKGROUND Patients with primary ciliary dyskinesia (PCD) have abnormal ciliary function and low nitric oxide levels. Nitric oxide (NO) biosynthesis is dependent on nitric oxide synthases (NOS). Cilia line the bronchial but not the alveolar epithelium. It has been hypothesised that NOS function relies on normal ciliary function and that in PCD bronchial but not alveolar NO might therefore be reduced. The aim of this study was to assess bronchial and alveolar NO levels primarily comparing healthy children to PCD and secondarily to cystic fibrosis (CF) and asthmatic children. METHODS Multiple flow-rate fractional exhaled and nasal NO measurements were performed using a NIOX(®) Flex NO analyser (Aerocrine, Sweden) in children with PCD (n = 14), asthma (n = 18), CF (n = 12) and healthy controls (n = 18). Alveolar and bronchial NO levels were derived using a model of pulmonary NO exchange-dynamics. RESULTS Both the bronchial and alveolar NO were significantly lower in PCD than healthy controls (mean (SD) 264 (209) picolitres/second (pl/s) vs. 720 (514) pl/s, p = 0.024 and 1.7 (0.8) parts per billion (ppb) vs. 3.5 (1.3) ppb, p = 0.001 respectively.) In asthmatics bronchial NO was found to be significantly higher than in healthy controls and in children with CF alveolar NO was significantly lower (2100 (1935) pl/s, p = 0.045 and 2.5 (1.2) ppb, p = 0.034 respectively.) CONCLUSION Our findings do not support the hypothesis that NOS and ciliary function are coupled instead suggesting a more generalised mechanism for the low levels of NO seen in PCD. Our findings in CF and asthma corroborate evidence that these are diseases of the lung peripheries and bronchi respectively.
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Affiliation(s)
- W T Walker
- Primary Ciliary Dyskinesia Centre, Southampton NIHR Respiratory Biomedical Research Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK.
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Abstract
Nitric oxide (NO) is now considered an important biomarker for respiratory disease. Studies have confirmed that the fractional concentration of exhaled nitric oxide (FENO) is elevated in the airways of patients who have asthma in comparison with controls. The level of FENO correlates well with the presence and level of inflammation, and decreases with glucocorticoid treatment. NO has potential to be used not only as a diagnostic aid but also as a management tool for assessing severity, monitoring response to therapy, and gaining control of asthma symptoms. This article reviews the biology of NO and its role in respiratory disease.
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Affiliation(s)
- Lora Stewart
- Allergy & Asthma Care and Prevention Center, Lone Tree, CO 80204, USA
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Linkosalo L, Lehtimäki L, Holm K, Kaila M, Moilanen E. Relation of bronchial and alveolar nitric oxide to exercise-induced bronchoconstriction in atopic children and adolescents. Pediatr Allergy Immunol 2012; 23:360-6. [PMID: 22145648 DOI: 10.1111/j.1399-3038.2011.01223.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND AND OBJECTIVE Exercise challenge test is widely used in diagnostics and follow-up of childhood asthma, but the method is complex, time consuming, and expensive. In this study, we aimed to find out whether flow-independent nitric oxide (NO) parameters (bronchial NO flux [J'aw(NO)] and alveolar NO concentration [CA(NO)]) predict exercise-induced bronchoconstriction (EIB) in atopic children and adolescents with asthma-like symptoms. Also, the respective NO parameters corrected for axial backward diffusion (J'aw(NO) [TMAD] and CA(NO) [TMAD]) were calculated and included in the analysis. METHODS Thirty patients (6-19 yr old) with confirmed atopy (positive skin prick tests or allergen-specific IgE) and asthma-like respiratory symptoms were included in the study. Before the current investigations, none of the patients had been diagnosed to have asthma and none were on inhaled corticosteroids. Exhaled NO was measured at multiple exhalation flow rates, and exercise challenge test was carried out. Bronchial NO flux and alveolar NO concentration were calculated according to the linear method with and without correction for axial backward diffusion. Sixty-six healthy school children served as controls. RESULTS The patients were divided into two groups according to EIB. Patients with EIB (EIB+ group, n = 18) had enhanced bronchial NO output as compared to patients without EIB (EIB- group, n = 12); but the EIB- group did not differ from healthy controls. EIB+ group had also higher alveolar NO concentration than EIB- group and healthy controls, but EIB- group did not differ from healthy controls. When bronchial NO flux and alveolar NO concentration were corrected for axial diffusion, J'aw(NO) (TMAD) had equal difference as J'aw(NO) between the groups as expected. However, only EIB+ had higher CA(NO) (TMAD) than healthy controls, and the patient groups did not differ from each other. In patients, bronchial NO output correlated with the magnitude of exercise-induced change in PEF (r(s) = -0.388, p = 0.034), FEV(1) (r(s) = -0.395, p = 0.031), and FEF(50%) (r(s) = -0.431, p = 0.020), i.e., the higher the bronchial NO output, the larger the decrease in PEF/FEV(1) /FEF(50%) . Alveolar NO concentrations correlated with the change in FEV(1) (r(s) = -0.439, p = 0.015), FEF(50%) (r(s) = -0.454, p = 0.013), FEF(75%) (r(s) = -0.447, p = 0.017), and FVC (r(s) = -0.375, p = 0.045). For J'aw(NO) (TMAD), the correlations and p-values were equal to those of J'aw(NO) , but, interestingly, CA(NO) (TMAD) had no significant correlations with any of the exercise-induced changes in lung function. CONCLUSION The results showed that in atopic children and adolescents, increased bronchial NO output as well as J'aw(NO) (TMAD) were associated with EIB, while alveolar NO concentration (but not CA(NO) [TMAD]) correlated with the degree of obstruction in smaller airways induced by exercise challenge.
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Affiliation(s)
- Laura Linkosalo
- The Immunopharmacology Research Group, University of Tampere School of Medicine and Tampere University Hospital, Tampere, Finland
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In moderate-to-severe asthma patients monitoring exhaled nitric oxide during exacerbation is not a good predictor of spirometric response to oral corticosteroid. J Allergy Clin Immunol 2012; 129:1491-8. [PMID: 22560478 DOI: 10.1016/j.jaci.2012.03.036] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 03/20/2012] [Accepted: 03/23/2012] [Indexed: 11/22/2022]
Abstract
BACKGROUND The importance of monitoring exhaled nitric oxide (NO) in asthma remains controversial. OBJECTIVE To measure exhaled NO, postnebulized albuterol/ipratropium spirometry, and Asthma Control Test (ACT) during asthma exacerbation requiring 8- to 10-day tapering oral corticosteroid in nonsmoking patients with moderate-to-severe asthma on moderate-dose inhaled corticosteroid and long-acting β(2)-agonist but not maintenance oral corticosteroid. METHODS After measuring the fraction of exhaled NO (Feno [ppb]) at 50, 100, 150, and 200 mL/s, the total Feno at 50 mL/s (ppb), large central airway NO flux (J'(awNO) [nL/s]), and peripheral small airway/alveolar NO concentration (C(ANO) [ppb]) were calculated and corrected for NO axial back-diffusion. Outpatient exacerbation required the patient with asthma to be afebrile with normal chest x-ray and white blood cell count. RESULTS Group 1 included 17 patients (6 men) with asthma, age 52 ± 12 years, studied at baseline, during 18 exacerbations with abnormal Feno at 50 mL/s, J'(awNO), and/or C(ANO), and post 8- to 10-day tapering 40 mg prednisone (recovery). Baseline: IgE, 332 ± 243 Kμ; total blood eosinophils, 304 ± 266 cells/μL; body mass index, 28 ± 6; ACT, 16 to 19; and FEV(1), 2.5 ± 0.7 L (86% ± 20% predicted); exacerbation: FEV(1), 1.7 ± 0.4 L (60% ± 17%) (P < .001); recovery: FEV(1), 2.5 ± 0.7 L (85% ± 13%) (P < .001). Group 2 included 11 (7 men) similarly treated patients with asthma, age 49 ± 14 years, studied at baseline, during 15 exacerbations with normal Feno at 50 mL/s, J'(awNO), and C(ANO). Baseline: IgE, 307 ± 133 Kμ; total blood eosinophils, 296 ± 149 cells/μL; body mass index, 28 ± 6; ACT, 16 to 19; and FEV(1), 2.7 ± 0.9 L (71% ± 12% predicted); exacerbation: FEV(1), 1.7 ± 0.6 L (54% ± 19%) (P< .006); recovery: FEV(1), 2.7 ± 0.9 L (70% ± 14%) (P= .002). On comparing group 1 versus group 2, there was no significant difference for baseline IgE, eosinophils, body mass index, and ACT and similar significant (≤.006) decrease from baseline in FEV(1) (L) during exacerbation and similar increase (≤.006) at recovery. CONCLUSIONS Increased versus normal exhaled NO during outpatient exacerbation in patients with moderate-to-severe asthma on inhaled corticosteroid and long-acting β(2)-agonist but not maintenance oral corticosteroid does not preclude a robust clinical and spirometric response to tapering oral prednisone.
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Mandon J, Högman M, Merkus PJFM, van Amsterdam J, Harren FJM, Cristescu SM. Exhaled nitric oxide monitoring by quantum cascade laser: comparison with chemiluminescent and electrochemical sensors. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:017003. [PMID: 22352669 DOI: 10.1117/1.jbo.17.1.017003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Fractional exhaled nitric oxide (F(E)NO) is considered an indicator in the diagnostics and management of asthma. In this study we present a laser-based sensor for measuring F(E)NO. It consists of a quantum cascade laser (QCL) combined with a multi-pass cell and wavelength modulation spectroscopy for the detection of NO at the sub-part-per-billion by volume (ppbv, 110(-9)) level. The characteristics and diagnostic performance of the sensor were assessed. A detection limit of 0.5 ppbv was demonstrated with a relatively simple design. The QCL-based sensor was compared with two market sensors, a chemiluminescent analyzer (NOA 280, Sievers) and a portable hand-held electrochemical analyzer (MINO, Aerocrine AB, Sweden). F(E)NO from 20 children diagnosed with asthma and treated with inhaled corticosteroids were measured. Data were found to be clinically acceptable within 1.1 ppbv between the QCL-based sensor and chemiluminescent sensor and within 1.7 ppbv when compared to the electrochemical sensor. The QCL-based sensor was tested on healthy subjects at various expiratory flow rates for both online and offline sampling procedures. The extended NO parameters, i.e. the alveolar region, airway wall, diffusing capacity, and flux were calculated and showed a good agreement with the previously reported values.
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Affiliation(s)
- Julien Mandon
- Radboud University, Life Science Trace Gas Facility, Molecular and Laser Physics, Institute for Molecules and Materials, PO Box 9010, 6500 GL Nijmegen, The Netherlands
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Kobayashi D, Tochino Y, Kanazawa H, Ichimaru Y, Kyoh S, Asai K, Hirata K. Comparison of alveolar nitric oxide concentrations using two different methods for assessing small airways obstruction in asthma. Respirology 2011; 16:862-8. [PMID: 21564400 DOI: 10.1111/j.1440-1843.2011.01989.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND AND OBJECTIVE Fractional exhaled nitric oxide (F(E) NO) is considered a potentially useful biomarker for airway inflammation. A two-compartment model (2CM) of pulmonary NO dynamics has been used for the evaluation of bronchial NO flux (J'awNO) and alveolar NO concentration (C(A) NO) in asthmatic patients. Recently, the trumpet shape of the airway tree and axial diffusion (TMAD) model has been reported as a modification of the 2CM. This study was designed to determine the validity of C(A) NO measurement using the TMAD model for assessing small airways inflammation in asthma. METHODS A total of 52 asthmatic patients and 12 normal control subjects were included in the study. Methacholine inhalation challenge and pulmonary function tests, sputum induction, and exhaled NO measurements at several flow rates were performed. J'awNO and C(A) NO were calculated using both the 2CM (C(A) NO( 2CM) , J'awNO( 2CM) ) and TMAD models (C(A) NO( TMAD) , J'awNO( TMAD) ). RESULTS Both J'awNO (J'awNO( 2CM) and J'awNO( TMAD) ) and C(A) NO (C(A) NO( 2CM) and C(A) NO( TMAD) ) were significantly higher in asthmatic patients than in control subjects. C(A) NO( 2CM) was significantly correlated with FEV(1) /FVC (r = -0.35, P = 0.01), FEF(25-75) (r = -0.45, P < 0.001) and sputum eosinophils (r = 0.32, P = 0.02). In contrast, C(A) NO( TMAD) was significantly correlated with FEF(25-75) (r = -0.42, P = 0.002) but not with FEV(1) /FVC or sputum eosinophils. CONCLUSIONS C(A) NO( TMAD) is more specific as an indicator of small airways obstruction than C(A) NO( 2CM) . Assessment of small airways obstruction using the TMAD model may clarify the role of the small airways in the pathogenesis of asthma.
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Affiliation(s)
- Daiki Kobayashi
- Department of Respiratory Medicine, Graduate School of Medicine, Osaka City University, Osaka, Japan.
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Bazeghi N, Gerds TA, Budtz-Jørgensen E, Hove J, Vestbo J. Exhaled nitric oxide measure using multiple flows in clinically relevant subgroups of COPD. Respir Med 2011; 105:1338-44. [DOI: 10.1016/j.rmed.2011.03.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 03/17/2011] [Accepted: 03/21/2011] [Indexed: 10/18/2022]
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Spears M, Weir CJ, Smith AD, McSharry C, Chaudhuri R, Johnson M, Cameron E, Thomson NC. Bronchial nitric oxide flux (J'aw) is sensitive to oral corticosteroids in smokers with asthma. Respir Med 2011; 105:1823-30. [PMID: 21840187 DOI: 10.1016/j.rmed.2011.06.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Revised: 06/29/2011] [Accepted: 06/29/2011] [Indexed: 11/29/2022]
Abstract
BACKGROUND Exhaled nitric oxide provides a convenient, non-invasive insight into airway inflammation. However it is suppressed by current smoking, reducing its potential as an endpoint in studies of smokers with asthma, a group with increased symptoms and poor clinical responses to corticosteroids. We examined extended nitric oxide analysis as some derived variables are thought to be unaffected. Therefore this approach could reveal hidden inflammation and enable its use as an exploratory endpoint in this group. METHODS Smokers (n = 22) and never smokers (n = 21) with asthma performed exhaled nitric oxide measurements and spirometry before and after two weeks of oral dexamethasone (6 mg/1.74 m(2)/day). Linear and non-linear nitric oxide analysis was performed to derive estimates for alveolar nitric oxide (C(alv)) and nitric oxide flux (J'(aw)) for each subject. RESULTS FE(NO50) was significantly lower in smokers with asthma and did not change significantly in response to dexamethasone. C(alv) derived by linear modelling was lower in smokers with asthma and did not change significantly in response in either group. J'(aw) was substantially lower in smokers with asthma (smokers (median (IQR)); 573 pl/s (217, 734), non-smoker; 1535 pl/s (785, 3496), p = 0.001) and was reduced in both groups following dexamethasone (non-smokers change (mean (95% CI)); -743.3 pl/s (-1710, -163), p = 0.005, smokers; -293 pl/s (-572, -60), p = 0.016). Correction for axial flow did not substantially change the derived results. CONCLUSIONS Bronchial NO flux appears to be sensitive to oral dexamethasone and may provide a useful exploratory endpoint for the analysis of novel anti-inflammatory therapies in smokers with asthma.
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Affiliation(s)
- Mark Spears
- Respiratory Medicine Section, Institute of Infection, Immunity & Inflammation, University of Glasgow & Gartnavel General Hospital, Asthma Research Unit, Level 6, 1053 Gt Western Rd, Glasgow G12 OYN, United Kingdom.
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