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Gill R, Boucher M, Henry C, Bossé Y. A Quick Method to Assess Airway Distensibility in Mice. Ann Biomed Eng 2024; 52:2193-2202. [PMID: 38619723 PMCID: PMC11247055 DOI: 10.1007/s10439-024-03518-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 04/11/2024] [Indexed: 04/16/2024]
Abstract
Airway distensibility is defined as the ease whereby airways are dilating in response to inflating lung pressure. If measured swiftly and accurately, airway distensibility would be a useful readout to parse the various elements contributing to airway wall stiffening, such as smooth muscle contraction, surface tension, and airway remodeling. The goal of the present study was to develop a method for measuring airway distensibility in mice. Lungs of BALB/c and C57BL/6 mice from either sex were subjected to stepwise changes in pressure. At each pressure step, an oscillometric perturbation was used to measure the impedance spectrum, on which the constant-phase model was fitted to deduce a surrogate for airway caliber called Newtonian conductance (GN). The change in GN over the change in pressure was subsequently used as an index of airway distensibility. An additional group of mice was infused with methacholine to confirm that smooth muscle contraction changes airway distensibility. GN increased with increasing steps in pressure, suggesting that the extent to which this occurs can be used as an index of airway distensibility. Airway distensibility was greater in BALB/c than C57BL/6 mice, and its variation by sex was mouse strain dependent, being greater in female than male in BALB/c mice with an inverse trend in C57BL/6 mice. Airway distensibility was also decreased by methacholine. This novel method swiftly measures airway distensibility in mice. Airway distensibility was also shown to vary with sex and mouse strain and to be sensitive to the contraction of smooth muscle.
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Affiliation(s)
- Rebecka Gill
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ)-Université Laval, 2725, Chemin Sainte-Foy, Quebec, QC, G1V 4G5, Canada
| | - Magali Boucher
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ)-Université Laval, 2725, Chemin Sainte-Foy, Quebec, QC, G1V 4G5, Canada
| | - Cyndi Henry
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ)-Université Laval, 2725, Chemin Sainte-Foy, Quebec, QC, G1V 4G5, Canada
| | - Ynuk Bossé
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ)-Université Laval, 2725, Chemin Sainte-Foy, Quebec, QC, G1V 4G5, Canada.
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2
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Rojas-Ruiz A, Boucher M, Henry C, Packwood R, Soliz J, Bossé Y. Lung Volumes in a Mouse Model of Pulmonary Allergic Inflammation. Lung 2024:10.1007/s00408-024-00730-1. [PMID: 39020115 DOI: 10.1007/s00408-024-00730-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2024] [Accepted: 07/04/2024] [Indexed: 07/19/2024]
Abstract
PURPOSE Air trapping, often attested in humans by elevated residual volume (RV) and ratio of RV on total lung capacity (RV/TLC), is frequently observed in asthma. Confirming these alterations in experimental asthma would be important for translational purposes. Herein, lung volumes were investigated in a mouse model of pulmonary allergic inflammation. METHODS Eight- to 10-week-old male C57BL/6 and BALB/c mice were exposed once daily to intranasal house dust mite (HDM) for 10 consecutive days. All readouts were measured 24 h after the last exposure. Lung volumes were assessed with the flexiVent using a new automated method consisting of degassing the lungs followed by a full-range pressure-volume maneuver. The weight and the volume of the lungs were also measured ex vivo and a lobe was further processed for histological analyses. RESULTS HDM exposure led to tissue infiltration with inflammatory cells, goblet cell hyperplasia, thickening of the airway epithelium, and elevated ex vivo lung weight and volume. It also decreased TLC and vital capacity but without affecting RV and RV/TLC. These observations were similar between the two mouse strains. CONCLUSION Alterations of lung volumes in a murine model of pulmonary allergic inflammation are inconsistent with observations made in human asthma. These discrepancies reflect the different means whereby lung volumes are measured between species. The invasive method used herein enables RV to be measured more precisely and without the confounding effect of air trapping, suggesting that changes in RV and RV/TLC using this method in mice should be interpreted differently than in humans.
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Affiliation(s)
- Andrés Rojas-Ruiz
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Université Laval, Pavillon M, Room 2687, 2725, Chemin Sainte-Foy, Québec, QC, G1V 4G5, Canada
| | - Magali Boucher
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Université Laval, Pavillon M, Room 2687, 2725, Chemin Sainte-Foy, Québec, QC, G1V 4G5, Canada
| | - Cyndi Henry
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Université Laval, Pavillon M, Room 2687, 2725, Chemin Sainte-Foy, Québec, QC, G1V 4G5, Canada
| | - Rosalie Packwood
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Université Laval, Pavillon M, Room 2687, 2725, Chemin Sainte-Foy, Québec, QC, G1V 4G5, Canada
| | - Jorge Soliz
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Université Laval, Pavillon M, Room 2687, 2725, Chemin Sainte-Foy, Québec, QC, G1V 4G5, Canada
| | - Ynuk Bossé
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Université Laval, Pavillon M, Room 2687, 2725, Chemin Sainte-Foy, Québec, QC, G1V 4G5, Canada.
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3
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Barreto M, Veneroni C, Caiulo M, Evangelisti M, Pompilio PP, Mazzuca MC, Raponi G, Pagani J, Parisi P. Within-breath oscillometry for identifying exercise-induced bronchoconstriction in pediatric patients reporting symptoms with exercise. Front Pediatr 2024; 11:1324413. [PMID: 38274467 PMCID: PMC10808442 DOI: 10.3389/fped.2023.1324413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 12/27/2023] [Indexed: 01/27/2024] Open
Abstract
Background Evaluating oscillometry parameters separately for the inspiratory and expiratory breath phases and their within-breath differences can help to identify exercise-induced bronchoconstriction (EIB) in pediatric outpatients disclosing exercise-induced symptoms (EIS). Aims To assess the response in impedance parameters following an exercise challenge in patients reporting EIS. Methods Sixty-eight patients reporting EIS (34 asthmatics and 34 suspected of asthma, age mean = 10.8 years, range = 6.0-16.0) underwent an incremental treadmill exercise test. Spirometry was performed at baseline and 1, 5-, 10-, 15-, and 20-min post exercise. Oscillometry was performed at baseline and at 3- and 18-min post exercise. Bronchodilator response to 200 µg albuterol was then assessed. EIB was defined as a forced expiratory volume in 1 s (FEV1) fall ≥10% from baseline. Expiratory and inspiratory resistance (Rrs) and reactance (Xrs), their z-score (Ducharme et al. 2022), and their mean within-breath differences (ΔRrs = Rrsexp-Rrsinsp, ΔXrs = Xrsexp-Xrsinsp) were calculated. Receiver operating characteristic (ROC) curves and their areas (AUCs) were used to evaluate impedance parameters' performances in classifying EIB. Results Asthmatic patients developed EIB more frequently than those suspected of asthma [18/34 (52.9%) vs. 2/34 (5.9%), p < 0.001]. In the 20 subjects with EIB, Rrsinsp, Rrsexp, Xrsinsp, and Xrsexp peaked early (3'), and remained steady except for Xrsinsp, which recovered faster afterward. ΔXrs widened 18 min following the exercise and reversed sharply after bronchodilation (BD) (-1.81 ± 1.60 vs. -0.52 ± 0.80 cmH2O × s/L, p < 0.001). Cutoffs for EIB leading to the highest AUCs were a rise of 0.41 in z-score Rrsinsp (Se: 90.0%, Sp: 66.7%), and a fall of -0.64 in z-score Xrsinsp (Se: 90.0%, Sp: 75.0%). Accepting as having "positive" postexercise oscillometry changes those subjects who had both z-scores beyond respective cutoffs, sensitivity for EIB was 90.0% (18/20) and specificity, 83.3% (40/48). Conclusion Oscillometry parameters and their within-breath differences changed markedly in pediatric patients presenting EIB and were restored after the bronchodilator. Strong agreement between z-scores of inspiratory oscillometry parameters and spirometry supports their clinical utility, though larger studies are required to validate these findings in a broader population.
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Affiliation(s)
- Mario Barreto
- NESMOS Department, Pediatric Unit Sant’Andrea Hospital, Faculty of Medicine and Psychology, “Sapienza” University, Rome, Italy
| | - Chiara Veneroni
- Department of Electronics, Information and Bioengineering, Politecnico di Milano University, Milano, Italy
| | - Mariaclaudia Caiulo
- NESMOS Department, Pediatric Unit Sant’Andrea Hospital, Faculty of Medicine and Psychology, “Sapienza” University, Rome, Italy
| | - Melania Evangelisti
- NESMOS Department, Pediatric Unit Sant’Andrea Hospital, Faculty of Medicine and Psychology, “Sapienza” University, Rome, Italy
| | | | - Maria Cristina Mazzuca
- NESMOS Department, Pediatric Unit Sant’Andrea Hospital, Faculty of Medicine and Psychology, “Sapienza” University, Rome, Italy
| | - Giorgia Raponi
- NESMOS Department, Pediatric Unit Sant’Andrea Hospital, Faculty of Medicine and Psychology, “Sapienza” University, Rome, Italy
| | - Jacopo Pagani
- NESMOS Department, Pediatric Unit Sant’Andrea Hospital, Faculty of Medicine and Psychology, “Sapienza” University, Rome, Italy
| | - Pasquale Parisi
- NESMOS Department, Pediatric Unit Sant’Andrea Hospital, Faculty of Medicine and Psychology, “Sapienza” University, Rome, Italy
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Henry C, Biardel S, Boucher M, Godbout K, Chakir J, Côté A, Laviolette M, Bossé Y. Bronchial thermoplasty attenuates bronchodilator responsiveness. Respir Med 2023; 217:107340. [PMID: 37422022 DOI: 10.1016/j.rmed.2023.107340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/31/2023] [Accepted: 06/25/2023] [Indexed: 07/10/2023]
Abstract
INTRODUCTION Bronchial thermoplasty is an effective intervention to improve respiratory symptoms and to reduce the rate of exacerbations in uncontrolled severe asthma. A reduction in airway smooth muscle is arguably the most widely discussed mechanisms accounting for these clinical benefits. Yet, this smooth muscle reduction should also translate into an impaired response to bronchodilator drugs. This study was designed to address this question. METHODS Eight patients with clinical indication for thermoplasty were studied. They were uncontrolled severe asthmatics despite optimal environmental control, treatment of comorbidities, and the use of high-dose inhaled corticosteroids and long-acting β2-agonists. Lung function measured by spirometry and respiratory mechanics measured by oscillometry were examined pre- and post-bronchodilator (salbutamol, 400 μg), both before and at least 1 year after thermoplasty. RESULTS Consistent with previous studies, thermoplasty yielded no benefits in terms of baseline lung function and respiratory mechanics, despite improving symptoms based on two asthma questionnaires (ACQ-5 and ACT-5). The response to salbutamol was also not affected by thermoplasty based on spirometric readouts, including forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), and FEV1/FVC ratio. However, a significant interaction was observed between thermoplasty and salbutamol for two oscillometric readouts, namely reactance at 5 Hz (Xrs5) and reactance area (Ax), showing an attenuated response to salbutamol after thermoplasty. CONCLUSIONS Thermoplasty attenuates the response to a bronchodilator. We argue that this result is a physiological proof of therapeutic efficacy, consistent with the well-described effect of thermoplasty in reducing the amount of airway smooth muscle.
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Affiliation(s)
- Cyndi Henry
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ) - Université Laval, Québec, Canada
| | - Sabrina Biardel
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ) - Université Laval, Québec, Canada
| | - Magali Boucher
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ) - Université Laval, Québec, Canada
| | - Krystelle Godbout
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ) - Université Laval, Québec, Canada
| | - Jamila Chakir
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ) - Université Laval, Québec, Canada
| | - Andréanne Côté
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ) - Université Laval, Québec, Canada
| | - Michel Laviolette
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ) - Université Laval, Québec, Canada
| | - Ynuk Bossé
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ) - Université Laval, Québec, Canada.
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Donohue P, Love NC, Connolly M, Khurana S, Georas SN. The effects of a deep breathing maneuver on standard airwave oscillometry measurements. Respir Med Res 2023; 83:100985. [PMID: 36563552 PMCID: PMC10241980 DOI: 10.1016/j.resmer.2022.100985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 10/24/2022] [Accepted: 11/26/2022] [Indexed: 12/12/2022]
Affiliation(s)
- Patrick Donohue
- Division of Pulmonary and Critical Care Medicine, University of Rochester School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY 14642, United States.
| | - Nicholas C Love
- Department of Medicine, University of Rochester School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY 14642, United States
| | - Margaret Connolly
- Division of Pulmonary and Critical Care Medicine, University of Rochester School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY 14642, United States
| | - Sandhya Khurana
- Division of Pulmonary and Critical Care Medicine, University of Rochester School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY 14642, United States; Mary Parkes Center for Asthma, Allergy & Pulmonary Care, 400 Red Creek Drive, Suite 110, Rochester, NY 14623, United States
| | - Steve N Georas
- Division of Pulmonary and Critical Care Medicine, University of Rochester School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY 14642, United States; Mary Parkes Center for Asthma, Allergy & Pulmonary Care, 400 Red Creek Drive, Suite 110, Rochester, NY 14623, United States
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O'Sullivan CF, Nilsen K, Borg BM, Ellis MJ, Matsas P, Thien F, Douglass JA, Stuart-Andrews C, King GG, Prisk GK, Thompson BR. Small Airways Dysfunction is Associated with Increased Exacerbations in Patients with Asthma. J Appl Physiol (1985) 2022; 133:629-636. [PMID: 35861519 DOI: 10.1152/japplphysiol.00103.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
There is poor understanding of why some patients with asthma experience recurrent exacerbations despite high levels of treatment. We compared measurements of peripheral ventilation heterogeneity and respiratory system mechanics in participants with asthma who were differentiated according to exacerbation history, to ascertain whether peripheral airway dysfunction was related to exacerbations. Three asthmatic groups: "Stable" (no exacerbations for >12 months, n=18), "Exacerbation-prone" (≥1 exacerbation requiring systemic corticosteroids within the last 12 months, but stable for ≥1-month, n=9) and "Treated-exacerbation" (exacerbation requiring systemic corticosteroids within the last 1 month, n=12) were studied. All participants were current non-smokers with <10pack/years smoking history. Spirometry, static lung volumes, ventilation heterogeneity from multi-breath nitrogen washout (MBW) and respiratory system mechanics from oscillometry were measured. The Exacerbation-prone group compared to the Stable group had slightly worse spirometry (FEV1 Z-score -3.58(1.13) vs -2.32(1.06), p=0.03), however acinar ventilation heterogeneity (Sacin Z-score 7.43(8.59) vs 3.63(3.88), p=0.006) and respiratory system reactance (Xrs cmH2O.s.L-1 -2.74(3.82) vs -1.32(1.94), p=0.01) were much worse in this group. The Treated-exacerbation group had worse spirometry but similar small airway function, compared with the Stable group. Patients with asthma who exacerbate have worse small airway function as evidenced by increases in Sacin measured by MBW and delta Xrs from oscillometry, both markers of small airway dysfunction, compared with those that do not.
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Affiliation(s)
- Claire F O'Sullivan
- Respiratory Medicine, The Alfred Hospital, Melbourne, VIC, Australia.,Monash University, Melbourne, VIC, Australia
| | - Kris Nilsen
- Respiratory Medicine, The Alfred Hospital, Melbourne, VIC, Australia.,School of Health Science, Swinburne University of Technology, Melbourne, VIC, Australia
| | - Brigitte M Borg
- Respiratory Medicine, The Alfred Hospital, Melbourne, VIC, Australia.,Monash University, Melbourne, VIC, Australia
| | - Matthew J Ellis
- Respiratory Medicine, The Alfred Hospital, Melbourne, VIC, Australia
| | - Pam Matsas
- Respiratory Medicine, The Alfred Hospital, Melbourne, VIC, Australia
| | - Frank Thien
- Monash University, Melbourne, VIC, Australia.,Respiratory Medicine, Eastern Health, Melbourne, VIC, Australia
| | - Jo A Douglass
- The Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Melbourne, VIC, Australia
| | | | - Gregory G King
- Airway Physiology and Imaging Group, The Woolcock Institute, Sydney, NSW, Australia
| | - Gordon Kim Prisk
- Department of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Bruce R Thompson
- Respiratory Medicine, The Alfred Hospital, Melbourne, VIC, Australia.,School of Health Science, University of Melbourne, Melbourne, VIC, Australia
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Pini L, Ziletti GC, Ciarfaglia M, Giordani J, Tantucci C. Acute Effect of Bronchodilator on Intrathoracic Airway Wall Compliance in COPD Patients. Lung 2022; 200:473-480. [PMID: 35851429 PMCID: PMC9360132 DOI: 10.1007/s00408-022-00556-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 07/03/2022] [Indexed: 12/01/2022]
Abstract
Purpose In patients with chronic obstructive pulmonary disease (COPD), bronchial responsiveness after acute administration of short acting bronchodilators is conventionally assessed by measuring the improvement of forced expiratory volume in the first second (FEV1) during a maximal forced expiratory maneuver. This study aimed to measure the variation of intrathoracic airway wall compliance (AWC) after acute administration of short acting beta-2 agonist in COPD patients since this might influence the final modification of airway caliber during maximal expiratory effort and the resulting bronchodilation as inferred by FEV1 changes. Methods In a group of 10 patients suffering from COPD, intrathoracic AWC was measured at middle (50% of Forced Vital Capacity (FVC) and low (75% of FVC) lung volumes using the interrupter method during forced expiratory maneuver in basal conditions and after acute inhalation of albuterol (salbutamol) (400 mcg by MDI). Ten healthy subjects were examined similarly as a control group. Results Lower values of baseline intrathoracic AWC at both lung volumes were found in COPD patients (1.72 ± 0.20 ml/cmH2O and 1.08 ± 0.20 ml/cmH2O, respectively) as compared to controls (2.28 ± 0.27 ml/cmH2O and 1.44 ± 0.22 ml/cmH2O, respectively) (p < 0.001). In COPD patients, AWC increased significantly at both lung volumes after salbutamol, amounting to 1.81 ± 0.38 ml/cmH2O and 1.31 ± 0.39 ml/cmH2O, respectively (p < 0.01), but the relative change was not different from that observed in controls. Conclusion In COPD patients, AWC is reduced compared to controls, but after bronchodilator, the intrathoracic airways become more compliant. The consequent increased collapsibility under high positive pleural pressure could limit the airway caliber improvement seen after bronchodilator, as assessed by the FEV1 changes during the forced expiratory maneuver, underestimating the effective bronchodilation achieved in these patients.
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Affiliation(s)
- Laura Pini
- Respiratory Medicine Unit, ASST - Spedali Civili di Brescia, Piazzale Spedali Civili 1, Brescia, Italy.
- Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy.
| | - Giulia Claudia Ziletti
- Respiratory Medicine Unit, ASST - Spedali Civili di Brescia, Piazzale Spedali Civili 1, Brescia, Italy
| | - Manuela Ciarfaglia
- Respiratory Medicine Unit, ASST - Spedali Civili di Brescia, Piazzale Spedali Civili 1, Brescia, Italy
| | - Jordan Giordani
- Respiratory Medicine Unit, ASST - Spedali Civili di Brescia, Piazzale Spedali Civili 1, Brescia, Italy
| | - Claudio Tantucci
- Respiratory Medicine Unit, ASST - Spedali Civili di Brescia, Piazzale Spedali Civili 1, Brescia, Italy
- Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy
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Boucher M, Dufour-Mailhot A, Tremblay-Pitre S, Khadangi F, Rojas-Ruiz A, Henry C, Bossé Y. In mice of both sexes, repeated contractions of smooth muscle in vivo greatly enhance the response of peripheral airways to methacholine. Respir Physiol Neurobiol 2022; 304:103938. [PMID: 35716869 DOI: 10.1016/j.resp.2022.103938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 05/10/2022] [Accepted: 06/12/2022] [Indexed: 10/18/2022]
Abstract
BALB/c mice from both sexes underwent one of two nebulized methacholine challenges that were preceded by a period of 20 min either with or without tone induced by repeated contractions of the airway smooth muscle. Impedance was monitored throughout and the constant phase model was used to dissociate the impact of tone on conducting airways (RN - Newtonian resistance) versus the lung periphery (G and H - tissue resistance and elastance). The effect of tone on smooth muscle contractility was also tested on excised tracheas. While tone markedly potentiated the methacholine-induced gains in H and G in both sexes, the gain in RN was only potentiated in males. The contractility of female and male tracheas was also potentiated by tone. Inversely, the methacholine-induced gain in hysteresivity (G/H) was mitigated by tone in both sexes. Therefore, the tone-induced muscle hypercontractility impacts predominantly the lung periphery in vivo, but also promotes further airway narrowing in males while protecting against narrowing heterogeneity in both sexes.
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Affiliation(s)
- Magali Boucher
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada
| | - Alexis Dufour-Mailhot
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada
| | - Sophie Tremblay-Pitre
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada
| | - Fatemeh Khadangi
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada
| | - Andrés Rojas-Ruiz
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada
| | - Cyndi Henry
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada
| | - Ynuk Bossé
- Institut Universitaire de Cardiologie et de Pneumologie de Québec - Université Laval, Québec, Canada.
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9
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Panagou P, Tzilas V, Bouros D. Dynamic lung compliance in non-smokers with asthma and fixed, non-reversible airflow obstruction. Eur Respir J 2021; 58:13993003.02361-2021. [PMID: 34561287 DOI: 10.1183/13993003.02361-2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Accepted: 09/06/2021] [Indexed: 11/05/2022]
Affiliation(s)
- Panagiotis Panagou
- Center of Excellence for Diseases of the Chest, Athens Medical Center, Athens, Greece
| | - Vasilios Tzilas
- Center of Excellence for Diseases of the Chest, Athens Medical Center, Athens, Greece
| | - Demosthenes Bouros
- Center of Excellence for Diseases of the Chest, Athens Medical Center, Athens, Greece .,Medical School, National and Kapodistrian University of Athens, Athens, Greece
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Robichaud A, Fereydoonzad L, Collins SL, Loube JM, Ishii Y, Horton MR, Martin JG, Mitzner W. Airway compliance measurements in mouse models of respiratory diseases. Am J Physiol Lung Cell Mol Physiol 2021; 321:L204-L212. [PMID: 34009049 DOI: 10.1152/ajplung.00470.2020] [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] [Indexed: 01/11/2023] Open
Abstract
The quantification of airway compliance (Caw) is essential to the study of airway alterations in disease models. However, the required measurements of airway pressure and volume are difficult to acquire in mice. We hypothesized that the inflation limb of full-range pressure-volume (PV) curves could be used to quantify Caw, as it contains a segment where only the airway tree is distended. The study objective was to assess the feasibility of the approach by analysis of full-range PV curves previously collected in three mouse models: an elastase model of emphysema, a genetic model spontaneously developing emphysema (leukotriene C4 synthase knockout; LTC4S-KO), and a bleomycin model of lung fibrosis. Attempts to validate results included Caw change relative to respiratory system compliance (ΔCaw/ΔC), the minute work of breathing (mWOB), and the elastance at 20.5 Hz (Ers_20.5) from prior respiratory mechanics measurements in the same subjects. Caw was estimated at 3% of total compliance in healthy mice or 2.3 ± 1 μL/cmH2O (n = 17). The technique detected changes in models of respiratory obstructive and restrictive diseases relative to control mice as well as differences in the two emphysema models studied. The changes in Caw were consistent with those seen in ΔCaw/ΔC, mWOB, or Ers_20.5, with some variations according to the model, as well as with results reported in the literature in humans and mice. Direct Caw measurements in subjects as small as mice could prove useful to further characterize other respiratory disease models associated with airway remodeling or to assess treatment effects.
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Affiliation(s)
| | | | - Samuel L Collins
- Johns Hopkins University School of Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Jeffrey Martin Loube
- Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland
| | - Yumiko Ishii
- Meakins-Christie Laboratories, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Maureen R Horton
- Johns Hopkins University School of Medicine, Johns Hopkins University, Baltimore, Maryland
| | - James G Martin
- Meakins-Christie Laboratories, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Wayne Mitzner
- Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland
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11
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Cottee AM, Seccombe LM, Thamrin C, Badal T, King GG, Peters MJ, Farah CS. Longitudinal monitoring of asthma in the clinic using respiratory oscillometry. Respirology 2021; 26:566-573. [PMID: 33797141 DOI: 10.1111/resp.14053] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Accepted: 02/23/2021] [Indexed: 01/18/2023]
Abstract
BACKGROUND AND OBJECTIVE Asthma guidelines emphasize the importance of assessing lung function and symptoms. The forced oscillation technique (FOT) and its longitudinal relationship with spirometry and symptoms are unresolved. We examined concordance between longitudinal spirometry, FOT and symptom control, and determined FOT limits of agreement in stable asthma. METHODS Over a 3-year period, adults with asthma attending a tertiary clinic completed the asthma control test (ACT), fraction of exhaled nitric oxide (FeNO), FOT and spirometry. Analysis included between-visit concordance for significant change using Cohen's kappa (κ) and stable asthma FOT limits of agreement. RESULTS Data (n = 186) from 855 visits (mean ± SD 4.6 ± 3.0 visits), 114 ± 95 days apart, were analysed. Between-visit concordance was moderate between reactance at 5 Hz (X5) and forced expiratory volume in 1 s (FEV1 ) (κ = 0.34, p = 0.001), and weak between ACT and FEV1 (κ = 0.18, p = 0.001). Change in FeNO did not correlate with lung function or ACT (κ < 0.05, p > 0.1). Stable asthma between visits (n = 75; 132 visits) had reduced lung function variability, but comparable concordance to the entire cohort. Limits of agreement for FEV1 (0.42 L), resistance at 5 Hz (2.06 cm H2 O s L-1 ) and X5 (2.75 cm H2 O s L-1 ) in stable asthma were at least twofold greater than published values in health. CONCLUSION In adults with asthma, there is moderate concordance between longitudinal change in FOT and spirometry. Both tests relate poorly to changes in asthma control, highlighting the need for multi-modal assessment in asthma rather than symptoms alone. The derivation of longitudinal FOT limits of agreement will assist in its clinical interpretation.
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Affiliation(s)
- Alice M Cottee
- Department of Respiratory Medicine, Concord Repatriation General Hospital, Concord, New South Wales, Australia.,Airway Physiology and Imaging Group and Woolcock Emphysema Centre, Woolcock Institute of Medical Research, Glebe, New South Wales, Australia.,Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
| | - Leigh M Seccombe
- Department of Respiratory Medicine, Concord Repatriation General Hospital, Concord, New South Wales, Australia.,Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
| | - Cindy Thamrin
- Airway Physiology and Imaging Group and Woolcock Emphysema Centre, Woolcock Institute of Medical Research, Glebe, New South Wales, Australia
| | - Tanya Badal
- Department of Respiratory Medicine, Concord Repatriation General Hospital, Concord, New South Wales, Australia.,Airway Physiology and Imaging Group and Woolcock Emphysema Centre, Woolcock Institute of Medical Research, Glebe, New South Wales, Australia.,Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
| | - Gregory G King
- Airway Physiology and Imaging Group and Woolcock Emphysema Centre, Woolcock Institute of Medical Research, Glebe, New South Wales, Australia.,Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia.,Department of Respiratory Medicine, Royal North Shore Hospital, St Leonards, New South Wales, Australia
| | - Matthew J Peters
- Department of Respiratory Medicine, Concord Repatriation General Hospital, Concord, New South Wales, Australia.,Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia.,Faculty of Medicine and Health Sciences, Macquarie University, North Ryde, New South Wales, Australia
| | - Claude S Farah
- Department of Respiratory Medicine, Concord Repatriation General Hospital, Concord, New South Wales, Australia.,Airway Physiology and Imaging Group and Woolcock Emphysema Centre, Woolcock Institute of Medical Research, Glebe, New South Wales, Australia.,Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia.,Faculty of Medicine and Health Sciences, Macquarie University, North Ryde, New South Wales, Australia
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12
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Veneroni C, Van Muylem A, Malinovschi A, Michils A, Dellaca' RL. Closing volume detection by single-breath gas washout and forced oscillation technique. J Appl Physiol (1985) 2021; 130:903-913. [PMID: 33475458 DOI: 10.1152/japplphysiol.00440.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Closing volume (CV) is commonly measured by single-breath nitrogen washout (CVSBW). A method based on the forced oscillation technique was recently introduced to detect a surrogate CV (CVFOT). As the two approaches are based on different physiological mechanisms, we aim to investigate CVFOT and CVSBW relationship at different degrees and patterns of airway obstruction. A mathematical model was developed to evaluate the CVSBW and CVFOT sensitivity to different patterns of airway obstruction, either located in a specific lung region or equally distributed throughout the lung. The two CVs were also assessed during slow vital capacity (VC) maneuvers in triplicate in 13 healthy subjects and pre- and postmethacholine challenge (Mch) in 12 subjects with mild-moderate asthma. Model simulations suggest that CVSBW is more sensitive than CVFOT to the presence of few flow-limited or closed airways that modify the contribution of tracer-poor and tracer-rich lung regions to the overall exhaled gas. Conversely, CVFOT occurs only when at least ∼65% of lung units are flow limited or closed, regardless of their regional distribution. CVSBW did not differ between healthy subjects and those with asthma (17 ± 9% VC vs. 22 ± 10% VC), whereas CVFOT did (16 ± 5% VC vs. 23 ± 6% VC, P < 0.01). In patients with asthma, both CVSBW and CVFOT increased post-Mch (33 ± 7% VC P < 0.001 and 43 ± 12% VC P < 0.001, respectively). CVSBW weakly correlated with CVFOT (r = 0.45, P < 0.01). The closing capacities (CV + residual volume) were correlated (r = 0.74, P < 0.001), but the changes with Mch in both CVs and closing capacities did not correlate. CVFOT is easy to measure and provides a reproducible parameter useful for describing airway impairment in obstructive respiratory diseases.NEW & NOTEWORTHY The forced oscillation technique can identify a surrogate of closing volume (CVFOT). We investigated its relationship with the one measured by single-breath washout (CVSBW). CVFOT weakly correlates with CVSBW. The respective closing capacities were correlated, but their increases after methacholine challenge in asthmatics did not. Our results suggest that CVFOT is less sensitive than CVSBW to few flow-limited/closed airways but more specific in detecting increases in flow-limited/closed airways involving the majority of the lung.
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Affiliation(s)
- Chiara Veneroni
- TechRes Lab, Department of Electronics, Information and Biomedical Engineering, Politecnico di Milano University, Milan, Italy
| | - Alain Van Muylem
- Chest Department, Erasme University Hospital/Université Libre de Bruxelles, Brussels, Belgium
| | - Andrei Malinovschi
- Department of Medical Sciences, Clinical Physiology, Uppsala University, Uppsala, Sweden
| | - Alain Michils
- Chest Department, Erasme University Hospital/Université Libre de Bruxelles, Brussels, Belgium
| | - Raffaele L Dellaca'
- TechRes Lab, Department of Electronics, Information and Biomedical Engineering, Politecnico di Milano University, Milan, Italy
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13
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Abstract
This article will discuss in detail the pathophysiology of asthma from the point of view of lung mechanics. In particular, we will explain how asthma is more than just airflow limitation resulting from airway narrowing but in fact involves multiple consequences of airway narrowing, including ventilation heterogeneity, airway closure, and airway hyperresponsiveness. In addition, the relationship between the airway and surrounding lung parenchyma is thought to be critically important in asthma, especially as related to the response to deep inspiration. Furthermore, dynamic changes in lung mechanics over time may yield important information about asthma stability, as well as potentially provide a window into future disease control. All of these features of mechanical properties of the lung in asthma will be explained by providing evidence from multiple investigative methods, including not only traditional pulmonary function testing but also more sophisticated techniques such as forced oscillation, multiple breath nitrogen washout, and different imaging modalities. Throughout the article, we will link the lung mechanical features of asthma to clinical manifestations of asthma symptoms, severity, and control. © 2020 American Physiological Society. Compr Physiol 10:975-1007, 2020.
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Affiliation(s)
- David A Kaminsky
- University of Vermont Larner College of Medicine, Burlington, Vermont, USA
| | - David G Chapman
- University of Technology Sydney, Sydney, New South Wales, Australia
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14
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Wang L, Chitano P, Seow CY. Mechanopharmacology of Rho-kinase antagonism in airway smooth muscle and potential new therapy for asthma. Pharmacol Res 2020; 159:104995. [PMID: 32534100 DOI: 10.1016/j.phrs.2020.104995] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 05/20/2020] [Accepted: 06/03/2020] [Indexed: 02/06/2023]
Abstract
The principle of mechanopharmacology of airway smooth muscle (ASM) is based on the premise that physical agitation, such as pressure oscillation applied to an airway, is able to induce bronchodilation by reducing contractility and softening the cytoskeleton of ASM. Although the underlying mechanism is not entirely clear, there is evidence to suggest that large-amplitude stretches are able to disrupt the actomyosin interaction in the crossbridge cycle and weaken the cytoskeleton in ASM cells. Rho-kinase is known to enhance force generation and strengthen structural integrity of the cytoskeleton during smooth muscle activation and plays a key role in the maintenance of force during prolonged muscle contractions. Synergy in relaxation has been observed when the muscle is subject to oscillatory length change while Rho-kinase is pharmacologically inhibited. In this review, inhibition of Rho-kinase coupled to therapeutic pressure oscillation applied to the airways is explored as a combination treatment for asthma.
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Affiliation(s)
- Lu Wang
- The Centre for Heart Lung Innovation, St. Paul's Hospital, University of British Columbia, Canada.
| | - Pasquale Chitano
- The Centre for Heart Lung Innovation, St. Paul's Hospital, University of British Columbia, Canada
| | - Chun Y Seow
- The Centre for Heart Lung Innovation, St. Paul's Hospital, University of British Columbia, Canada
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15
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King GG, Bates J, Berger KI, Calverley P, de Melo PL, Dellacà RL, Farré R, Hall GL, Ioan I, Irvin CG, Kaczka DW, Kaminsky DA, Kurosawa H, Lombardi E, Maksym GN, Marchal F, Oppenheimer BW, Simpson SJ, Thamrin C, van den Berge M, Oostveen E. Technical standards for respiratory oscillometry. Eur Respir J 2020; 55:13993003.00753-2019. [PMID: 31772002 DOI: 10.1183/13993003.00753-2019] [Citation(s) in RCA: 282] [Impact Index Per Article: 70.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Accepted: 10/15/2019] [Indexed: 12/11/2022]
Abstract
Oscillometry (also known as the forced oscillation technique) measures the mechanical properties of the respiratory system (upper and intrathoracic airways, lung tissue and chest wall) during quiet tidal breathing, by the application of an oscillating pressure signal (input or forcing signal), most commonly at the mouth. With increased clinical and research use, it is critical that all technical details of the hardware design, signal processing and analyses, and testing protocols are transparent and clearly reported to allow standardisation, comparison and replication of clinical and research studies. Because of this need, an update of the 2003 European Respiratory Society (ERS) technical standards document was produced by an ERS task force of experts who are active in clinical oscillometry research.The aim of the task force was to provide technical recommendations regarding oscillometry measurement including hardware, software, testing protocols and quality control.The main changes in this update, compared with the 2003 ERS task force document are 1) new quality control procedures which reflect use of "within-breath" analysis, and methods of handling artefacts; 2) recommendation to disclose signal processing, quality control, artefact handling and breathing protocols (e.g. number and duration of acquisitions) in reports and publications to allow comparability and replication between devices and laboratories; 3) a summary review of new data to support threshold values for bronchodilator and bronchial challenge tests; and 4) updated list of predicted impedance values in adults and children.
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Affiliation(s)
- Gregory G King
- Dept of Respiratory Medicine and Airway Physiology and Imaging Group, Royal North Shore Hospital and The Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia
| | - Jason Bates
- Dept of Medicine, Pulmonary/Critical Care Division, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - Kenneth I Berger
- Division of Pulmonary, Critical Care, and Sleep Medicine, NYU School of Medicine and André Cournand Pulmonary Physiology Laboratory, Belleuve Hospital, New York, NY, USA
| | - Peter Calverley
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - Pedro L de Melo
- Institute of Biology and Faculty of Engineering, Department of Physiology, Biomedical Instrumentation Laboratory, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Raffaele L Dellacà
- Dipartimento di Elettronica, Informazione e Bioingegneria - DEIB, Politecnico di Milano University, Milano, Italy
| | - Ramon Farré
- Unitat de Biofísica i Bioenginyeria, Facultat de Medicina, Universitat de Barcelona-IDIBAPS, Barcelona, Spain.,CIBER de Enfermedades Respiratorias, Madrid, Spain
| | - Graham L Hall
- Children's Lung Health, Telethon Kids Institute, School of Physiotherapy and Exercise Science, Curtin University, Perth, Australia
| | - Iulia Ioan
- Dept of Pediatric Lung Function Testing, Children's Hospital, Vandoeuvre-lès-Nancy, France.,EA 3450 DevAH - Laboratory of Physiology, Faculty of Medicine, University of Lorraine, Vandoeuvre-lès-Nancy, France
| | - Charles G Irvin
- Dept of Medicine, Pulmonary/Critical Care Division, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - David W Kaczka
- Depts of Anesthesia, Biomedical Engineering and Radiology, University of Iowa, Iowa City, IA, USA
| | - David A Kaminsky
- Dept of Medicine, Pulmonary/Critical Care Division, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - Hajime Kurosawa
- Dept of Occupational Health, Tohoku University School of Medicine, Sendai, Japan
| | - Enrico Lombardi
- Pediatric Pulmonary Unit, Meyer Pediatric University Hospital, Florence, Italy
| | - Geoffrey N Maksym
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada
| | - François Marchal
- Dept of Pediatric Lung Function Testing, Children's Hospital, Vandoeuvre-lès-Nancy, France.,EA 3450 DevAH - Laboratory of Physiology, Faculty of Medicine, University of Lorraine, Vandoeuvre-lès-Nancy, France
| | - Beno W Oppenheimer
- Division of Pulmonary, Critical Care, and Sleep Medicine, NYU School of Medicine and André Cournand Pulmonary Physiology Laboratory, Belleuve Hospital, New York, NY, USA
| | - Shannon J Simpson
- Children's Lung Health, Telethon Kids Institute, School of Physiotherapy and Exercise Science, Curtin University, Perth, Australia
| | - Cindy Thamrin
- Dept of Respiratory Medicine and Airway Physiology and Imaging Group, Royal North Shore Hospital and The Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia
| | - Maarten van den Berge
- University of Groningen, University Medical Center Groningen, Dept of Pulmonary Diseases, Groningen, The Netherlands
| | - Ellie Oostveen
- Dept of Respiratory Medicine, Antwerp University Hospital and University of Antwerp, Antwerp, Belgium
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16
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Bhatawadekar SA, Leary D, de Lange V, Peters U, Fulton S, Hernandez P, McParland C, Maksym GN. Reactance and elastance as measures of small airways response to bronchodilator in asthma. J Appl Physiol (1985) 2019; 127:1772-1781. [PMID: 31647721 DOI: 10.1152/japplphysiol.01131.2018] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Bronchodilation alters both respiratory system resistance (Rrs) and reactance (Xrs) in asthma, but how changes in Rrs and Xrs compare, and respond differently in health and asthma, in reflecting the contributions from the large and small airways has not been assessed. We assessed reversibility using spirometry and oscillometry in healthy and asthma subjects. Using a multibranch airway-tree model with the mechanics of upper airway shunt, we compared the effects of airway dilation and small airways recruitment to explain the changes in Rrs and Xrs. Bronchodilator decreased Rrs by 23.0 (19.0)% in 18 asthma subjects and by 13.5 (19.5)% in 18 healthy subjects. Estimated respiratory system elastance (Ers) decreased by 23.2 (21.4)% in asthma, with no significant decrease in healthy subjects. With the use of the model, airway recruitment of 15% across a generation of the small airways could explain the changes in Ers in asthma with no recruitment in healthy subjects. In asthma, recruitment accounted for 40% of the changes in Rrs, with the remaining explained by airway dilation of 6.8% attributable largely to the central airways. Interestingly, the same dilation magnitude explained the changes in Rrs in healthy subjects. Shunt only affected Rrs of the model. Ers was unaltered in health and unaffected by shunt in both groups. In asthma, Ers changed comparably to Rrs and could be attributed to small airways, while the change in Rrs was split between large and small airways. This implies that in asthma Ers sensed through Xrs may be a more effective measure of small airways obstruction and recruitment than Rrs.NEW & NOTEWORTHY This is the first study to quantify to relative contributions of small and large airways to bronchodilator response in healthy subjects and patients with asthma. The response of the central airways to bronchodilator was similar in magnitude in both study groups, whereas the response of the small airways was significant among patients with asthma. These results suggest that low-frequency reactance and derived elastance are both sensitive measures of small airway function in asthma.
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Affiliation(s)
- S A Bhatawadekar
- School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada.,Department of Medicine, University of Vermont College of Medicine, Burlington, Vermont
| | - D Leary
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, Colorado
| | - V de Lange
- School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada
| | - U Peters
- Department of Medicine, University of Vermont College of Medicine, Burlington, Vermont
| | - S Fulton
- Division of Respirology, QE-II Health Sciences Centre, Halifax, Nova Scotia, Canada
| | - P Hernandez
- Division of Respirology, QE-II Health Sciences Centre, Halifax, Nova Scotia, Canada.,Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - C McParland
- Division of Respirology, QE-II Health Sciences Centre, Halifax, Nova Scotia, Canada.,Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - G N Maksym
- School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada
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17
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Langton D, Sloan G, Banks C, Bennetts K, Plummer V, Thien F. Bronchial thermoplasty increases airway volume measured by functional respiratory imaging. Respir Res 2019; 20:157. [PMID: 31311604 PMCID: PMC6636001 DOI: 10.1186/s12931-019-1132-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Accepted: 07/10/2019] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND The purpose of this study was to use CT scanning with computational fluid dynamics to evaluate the mechanisms by which Bronchial Thermoplasty (BT) improves asthmatic symptoms. METHODS The study was conducted in a university teaching hospital, experienced in performing BT. Imaging studies were performed before, and after, BT of the left lung, and prior to treatment of the right lung, which therefore acted as a control. On each occasion, two high-resolution CT scans were performed, one at full inspiration (TLC) and the other at Functional Residual Capacity (FRC). The study protocol was offered to 10 patients, all of whom met the definition of severe asthma, despite high dose inhaled corticosteroids and dual long acting bronchodilators. RESULTS Significant increases in airway luminal volume were observed on the treated side, compared with control, at both full inspiration (by 27%) and at FRC (by 17%). The ratio of distal airway volume to lung volume significantly increased on the treated side. The change in airway volume with inspiration from FRC increased by 48% on the treated side compared to 5% in the control lung, suggesting treatment increased airway distensibility. No effect was observed on airway wall thickness, nor air trapping. There was a trend towards correlation between the improvement in airway volume at TLC and improvement in symptoms. CONCLUSION This study demonstrates that BT increases the luminal airway volume on the treated side compared to the control lung. We suggest that this is an important link between the airway smooth muscle atrophy demonstrated pathologically, and the improvement in symptoms observed clinically.
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Affiliation(s)
- D Langton
- Department of Thoracic Medicine, Frankston Hospital, Peninsula Health, 2 Hastings Road, Frankston, VIC, 3199, Australia. .,Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Vic, Australia.
| | - G Sloan
- Department of Medical Imaging, Frankston Hospital, Peninsula Health, Frankston, Vic, Australia
| | - C Banks
- Department of Thoracic Medicine, Frankston Hospital, Peninsula Health, 2 Hastings Road, Frankston, VIC, 3199, Australia
| | - K Bennetts
- Department of Thoracic Medicine, Frankston Hospital, Peninsula Health, 2 Hastings Road, Frankston, VIC, 3199, Australia
| | - V Plummer
- Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Vic, Australia
| | - F Thien
- Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Vic, Australia.,Department of Respiratory Medicine, Eastern Health, Box Hill, Vic, Australia
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18
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Zimmermann SC, Tonga KO, Thamrin C. Dismantling airway disease with the use of new pulmonary function indices. Eur Respir Rev 2019; 28:28/151/180122. [PMID: 30918023 PMCID: PMC9488242 DOI: 10.1183/16000617.0122-2018] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Accepted: 02/15/2019] [Indexed: 11/27/2022] Open
Abstract
We are currently limited in our abilities to diagnose, monitor disease status and manage chronic airway disease like asthma and chronic obstructive pulmonary disease (COPD). Conventional lung function measures often poorly reflect patient symptoms or are insensitive to changes, particularly in the small airways where disease may originate or manifest. Novel pulmonary function tests are becoming available which help us better characterise and understand chronic airway disease, and their translation and adoption from the research arena would potentially enable individualised patient care. In this article, we aim to describe two emerging lung function tests yielding novel pulmonary function indices, the forced oscillation technique (FOT) and multiple breath nitrogen washout (MBNW). With a particular focus on asthma and COPD, this article demonstrates how chronic airway disease mechanisms have been dismantled with the use of the FOT and MBNW. We describe their ability to assess detailed pulmonary mechanics for diagnostic and management purposes including response to bronchodilation and other treatments, relationship with symptoms, evaluation of acute exacerbations and recovery, and telemonitoring. The current limitations of both tests, as well as open questions/directions for further research, are also discussed. Spirometry is used to diagnose and manage airway disease such as asthma and COPD, but relates poorly to symptoms, lacks sensitivity and is effort dependent. FOT and MBNW are emerging clinical lung function tests that help us dismantle disease mechanisms.http://ow.ly/nM0G30nS6Ct
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Affiliation(s)
- Sabine C Zimmermann
- Airway Physiology and Imaging Group, Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia.,Dept of Respiratory Medicine, Royal North Shore Hospital, Sydney, Australia.,Sydney Medical School Northern, The University of Sydney, Sydney, Australia.,Woolcock Emphysema Centre, Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia
| | - Katrina O Tonga
- Airway Physiology and Imaging Group, Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia.,Dept of Respiratory Medicine, Royal North Shore Hospital, Sydney, Australia.,Sydney Medical School Northern, The University of Sydney, Sydney, Australia.,Woolcock Emphysema Centre, Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia.,Dept of Thoracic and Transplant Medicine, St Vincent's Hospital, Sydney, Australia.,Faculty of Medicine, The University of New South Wales, Sydney, Australia
| | - Cindy Thamrin
- Airway Physiology and Imaging Group, Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia .,Woolcock Emphysema Centre, Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia
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19
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Milne S, Jetmalani K, Chapman DG, Duncan JM, Farah CS, Thamrin C, King GG. Respiratory system reactance reflects communicating lung volume in chronic obstructive pulmonary disease. J Appl Physiol (1985) 2019; 126:1223-1231. [PMID: 30763164 DOI: 10.1152/japplphysiol.00503.2018] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Respiratory system reactance (Xrs) measured by the forced oscillation technique (FOT) is theoretically and experimentally related to lung volume. In chronic obstructive pulmonary disease (COPD), the absolute volume measured by body plethysmography includes a proportion that is inaccessible to pressure oscillations applied via the mouth, that is, a "noncommunicating" lung volume. We hypothesized that in COPD the presence of noncommunicating lung would disrupt the expected Xrs-volume relationship compared with plethysmographic functional residual capacity (FRCpleth). Instead, Xrs would relate to estimates of communicating volume, namely, expiratory reserve volume (ERV) and single-breath alveolar volume (VaSB). We examined FOT and lung function data from people with COPD (n = 51) and from healthy volunteers (n = 40). In healthy volunteers, we observed an expected inverse relationship between reactance at 5 Hz (X5) and FRCpleth. In contrast, there was no such relationship between X5 and FRCpleth in COPD subjects. However, there was an inverse relationship between X5 and both ERV and VaSB. Hence the theoretical Xrs-volume relationship is present in COPD but only when considering the communicating volume rather than the absolute lung volume. These findings confirm the role of reduced communicating lung volume as an important determinant of Xrs and therefore advance our understanding and interpretation of FOT measurements in COPD. NEW & NOTEWORTHY To investigate the determinants of respiratory system reactance (Xrs) measured by the forced oscillation technique (FOT) in chronic obstructive pulmonary disease (COPD), we examine the relationship between Xrs and lung volume. We show that Xrs does not relate to absolute lung volume (functional residual capacity) in COPD but instead relates only to the volume of lung in communication with the airway opening. This communicating volume may therefore be fundamental to our interpretation of FOT measurements in COPD and other pulmonary diseases.
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Affiliation(s)
- Stephen Milne
- The Woolcock Emphysema Centre and Airway Physiology and Imaging Group, Woolcock Institute of Medical Research and Sydney Medical School, University of Sydney, Glebe, New South Wales , Australia.,Department of Respiratory Medicine, Royal North Shore Hospital, Northern Sydney Local Health District, St Leonards, New South Wales , Australia.,Department of Respiratory Medicine, Concord Repatriation General Hospital, Sydney Local Health District, Concord, New South Wales , Australia
| | - Kanika Jetmalani
- The Woolcock Emphysema Centre and Airway Physiology and Imaging Group, Woolcock Institute of Medical Research and Sydney Medical School, University of Sydney, Glebe, New South Wales , Australia
| | - David G Chapman
- The Woolcock Emphysema Centre and Airway Physiology and Imaging Group, Woolcock Institute of Medical Research and Sydney Medical School, University of Sydney, Glebe, New South Wales , Australia.,Translational Airways Group, School of Life Sciences, University of Technology Sydney , Ultimo, New South Wales , Australia
| | - Joseph M Duncan
- Department of Respiratory Medicine, Royal North Shore Hospital, Northern Sydney Local Health District, St Leonards, New South Wales , Australia
| | - Claude S Farah
- The Woolcock Emphysema Centre and Airway Physiology and Imaging Group, Woolcock Institute of Medical Research and Sydney Medical School, University of Sydney, Glebe, New South Wales , Australia.,Department of Respiratory Medicine, Concord Repatriation General Hospital, Sydney Local Health District, Concord, New South Wales , Australia.,Faculty of Medicine and Health Sciences, Macquarie University , North Ryde, New South Wales , Australia
| | - Cindy Thamrin
- The Woolcock Emphysema Centre and Airway Physiology and Imaging Group, Woolcock Institute of Medical Research and Sydney Medical School, University of Sydney, Glebe, New South Wales , Australia
| | - Gregory G King
- The Woolcock Emphysema Centre and Airway Physiology and Imaging Group, Woolcock Institute of Medical Research and Sydney Medical School, University of Sydney, Glebe, New South Wales , Australia.,Department of Respiratory Medicine, Royal North Shore Hospital, Northern Sydney Local Health District, St Leonards, New South Wales , Australia.,Centre of Research Excellence in Severe Asthma, New Lambton, New South Wales , Australia
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20
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Bossé Y. The Strain on Airway Smooth Muscle During a Deep Inspiration to Total Lung Capacity. JOURNAL OF ENGINEERING AND SCIENCE IN MEDICAL DIAGNOSTICS AND THERAPY 2019; 2:0108021-1080221. [PMID: 32328568 PMCID: PMC7164505 DOI: 10.1115/1.4042309] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/06/2018] [Indexed: 02/05/2023]
Abstract
The deep inspiration (DI) maneuver entices a great deal of interest because of its ability to temporarily ease the flow of air into the lungs. This salutary effect of a DI is proposed to be mediated, at least partially, by momentarily increasing the operating length of airway smooth muscle (ASM). Concerningly, this premise is largely derived from a growing body of in vitro studies investigating the effect of stretching ASM by different magnitudes on its contractility. The relevance of these in vitro findings remains uncertain, as the real range of strains ASM undergoes in vivo during a DI is somewhat elusive. In order to understand the regulation of ASM contractility by a DI and to infer on its putative contribution to the bronchodilator effect of a DI, it is imperative that in vitro studies incorporate levels of strains that are physiologically relevant. This review summarizes the methods that may be used in vivo in humans to estimate the strain experienced by ASM during a DI from functional residual capacity (FRC) to total lung capacity (TLC). The strengths and limitations of each method, as well as the potential confounders, are also discussed. A rough estimated range of ASM strains is provided for the purpose of guiding future in vitro studies that aim at quantifying the regulatory effect of DI on ASM contractility. However, it is emphasized that, owing to the many limitations and confounders, more studies will be needed to reach conclusive statements.
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Affiliation(s)
- Ynuk Bossé
- Université Laval, Faculty of Medicine, Department of Medicine, IUCPQ, M2694, Pavillon Mallet, Chemin Sainte-Foy, Québec, QC G1V 4G5, Canada e-mail:
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Nilsen K, Thien F, Thamrin C, Ellis MJ, Prisk GK, King GG, Thompson BR. Early onset of airway derecruitment assessed using the forced oscillation technique in subjects with asthma. J Appl Physiol (1985) 2019; 126:1399-1408. [PMID: 30702975 DOI: 10.1152/japplphysiol.00534.2018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Derecruitment of air spaces in the lung occurs when airways close during exhalation and is related to ventilation heterogeneity and symptoms in asthma. The forced oscillation technique has been used to identify surrogate measures of airway closure via the reactance (Xrs) versus lung volume relationship. This study used a new algorithm to identify derecruitment from the Xrs versus lung volume relationship from a slow vital capacity maneuver. We aimed to compare two derecruitment markers on the Xrs versus volume curve, the onset reduction of Xrs (DR1vol) and the onset of more rapid reduction of Xrs (DR2vol), between control and asthmatic subjects. We hypothesized that the onset of DR1vol and DR2vol occurred at higher lung volume in asthmatic subjects. DR1vol and DR2vol were measured in 18 subjects with asthma and 18 healthy controls, and their relationships with age and height were examined using linear regression. In the control group, DR1vol and DR2vol increased with age (r2 = 0.68, P < 0.001 and r2 = 0.71, P < 0.001, respectively). DR1vol and DR2vol in subjects with asthma [76.58% of total lung capacity (TLC) and 56.79%TLC, respectively] were at higher lung volume compared with control subjects (46.1 and 37.69%TLC, respectively) (P < 0.001). DR2vol correlated with predicted values of closing capacity (r = 0.94, P < 0.001). This study demonstrates that derecruitment occurs at two points along the Xrs-volume relationship. Both derecruitment points occurred at significantly higher lung volumes in subjects with asthma compared with healthy control subjects. This technique offers a novel way to measure the effects of changes in airways/lung mechanics. NEW & NOTEWORTHY This study demonstrates that the forced oscillation technique can be used to identify two lung volume points where lung derecruitment occurs: 1) where derecruitment is initiated and 2) where onset of rapid derecruitment commences. Measurements of derecruitment increase with age. The onset of rapid derecruitment was highly correlated with predicted closing capacity. Also, the initiation and rate of derecruitment are significantly altered in subjects with asthma.
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Affiliation(s)
- Kris Nilsen
- Central Clinical School, Monash University , Melbourne, Victoria , Australia.,Allergy Immunology and Respiratory Medicine, The Alfred Hospital , Melbourne, Victoria , Australia
| | - Francis Thien
- Eastern Health Clinical School, Monash University , Melbourne, Victoria , Australia.,Box Hill Hospital , Melbourne, Victoria , Australia
| | - Cindy Thamrin
- Woolcock Institute of Medical Research, University of Sydney , Sydney, New South Wales , Australia.,Department of Respiratory Medicine, Royal North Shore Hospital , St. Leonards, New South Wales , Australia
| | - Matt J Ellis
- Allergy Immunology and Respiratory Medicine, The Alfred Hospital , Melbourne, Victoria , Australia
| | - G Kim Prisk
- Department of Medicine, Division of Physiology, University of California , San Diego, California
| | - Gregory G King
- Woolcock Institute of Medical Research, University of Sydney , Sydney, New South Wales , Australia.,Department of Respiratory Medicine, Royal North Shore Hospital , St. Leonards, New South Wales , Australia
| | - Bruce R Thompson
- Central Clinical School, Monash University , Melbourne, Victoria , Australia.,Allergy Immunology and Respiratory Medicine, The Alfred Hospital , Melbourne, Victoria , Australia
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22
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Comparison of two methods of determining lung de-recruitment, using the forced oscillation technique. Eur J Appl Physiol 2018; 118:2213-2224. [PMID: 30062516 DOI: 10.1007/s00421-018-3949-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 07/21/2018] [Indexed: 10/28/2022]
Abstract
Airway closure has proved to be important in a number of respiratory diseases and may be the primary functional defect in asthma. A surrogate measure of closing volume can be identified using the forced oscillation technique (FOT), by performing a deflation maneuver and examining the resultant reactance (Xrs) lung volume relationship. This study aims to determine if a slow vital capacity maneuver can be used instead of this deflation maneuver and compare it to existing more complex techniques. Three subject groups were included in the study; healthy (n = 29), asthmatic (n = 18), and COPD (n = 10) for a total of 57 subjects. Reactance lung volume curves were generated via FOT recordings during two different breathing manoeuvres (both pre and post bronchodilator). The correlation and agreement between surrogate closing volume (Volcrit) and reactance (Xrscrit) at this volume was analysed. The changes in Volcrit and Xrscrit pre and post bronchodilator were also analysed. Across all three subject groups, the two different measures of Volcrit were shown to be statistically equivalent (p > 0.05) and demonstrated a strong fit to the data (R2 = 0.49, 0.78, 0.59, for asthmatic, COPD and healthy subject groups, respectively). A bias was evident between the two measurements of Xrscrit with statistically different means (p < 0.05). However, the two measurements of Xrscrit displayed the same trends. In conclusion, we have developed an alternative technique for measuring airway closure from FOT recordings. The technique delivers equivalent and possibly more sensitive results to previous methods while being simple and easily performed by the patient.
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23
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Milne S, Hammans C, Watson S, Farah CS, Thamrin C, King GG. Bronchodilator Responses in Respiratory Impedance, Hyperinflation and Gas Trapping in COPD. COPD 2018; 15:341-349. [PMID: 29799289 DOI: 10.1080/15412555.2018.1458217] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Hyperinflation, gas trapping and their responses to long-acting bronchodilator are clinically important in COPD. The forced oscillation technique (FOT) measures of respiratory system resistance and reactance are sensitive markers of bronchodilator response in COPD. The relationships between changes in resistance and reactance, and changes in hyperinflation and gas trapping, following long-acting bronchodilator (LA-BD) have not been studied. 15 subjects with mild-moderate COPD underwent FOT, spirometry then body plethysmography, before and 2 hours after a single 150 microg dose of the LA-BD indacaterol. Hyperinflation was quantified as the inspiratory capacity to total lung capacity ratio (IC/TLC), and gas trapping as residual volume to TLC ratio (RV/TLC). At baseline, FOT parameters were moderately correlated with IC/TLC (|r| 0.53-0.73, p < 0.05). At 2 hours post-LA-BD, there were moderate correlations between change in FOT and change in RV/TLC (|r| 0.60-0.82, p < 0.05). Baseline FOT parameters also correlated with the subsequent post-LA-BD change in both IC/TLC (|r| 0.54-0.62, p < 0.05) and RV/TLC (|r| 0.57-0.76, p < 0.05). FOT impedance reflects hyperinflation and gas trapping in COPD, and the potential for long-acting bronchodilator responsiveness. These results provide us with further insight into the physiological mechanisms of action of long-acting bronchodilator treatment, and may be clinically useful for predicting treatment responses.
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Affiliation(s)
- Stephen Milne
- a The Woolcock Emphysema Centre and Airway Physiology and Imaging Group, Woolcock Institute of Medical Research and Sydney Medical School , University of Sydney , NSW , Australia.,b Department of Respiratory Medicine , Concord Repatriation General Hospital, Sydney Local Health District , Concord , NSW , Australia.,c Department of Respiratory Medicine , Royal North Shore Hospital, Northern Sydney Local Health District , St Leonards , NSW , Australia
| | - Christoph Hammans
- a The Woolcock Emphysema Centre and Airway Physiology and Imaging Group, Woolcock Institute of Medical Research and Sydney Medical School , University of Sydney , NSW , Australia
| | - Stella Watson
- a The Woolcock Emphysema Centre and Airway Physiology and Imaging Group, Woolcock Institute of Medical Research and Sydney Medical School , University of Sydney , NSW , Australia
| | - Claude S Farah
- a The Woolcock Emphysema Centre and Airway Physiology and Imaging Group, Woolcock Institute of Medical Research and Sydney Medical School , University of Sydney , NSW , Australia.,b Department of Respiratory Medicine , Concord Repatriation General Hospital, Sydney Local Health District , Concord , NSW , Australia.,d Faculty of Medicine and Health Sciences , Macquarie University , North Ryde , NSW , Australia
| | - Cindy Thamrin
- a The Woolcock Emphysema Centre and Airway Physiology and Imaging Group, Woolcock Institute of Medical Research and Sydney Medical School , University of Sydney , NSW , Australia
| | - Gregory G King
- a The Woolcock Emphysema Centre and Airway Physiology and Imaging Group, Woolcock Institute of Medical Research and Sydney Medical School , University of Sydney , NSW , Australia.,c Department of Respiratory Medicine , Royal North Shore Hospital, Northern Sydney Local Health District , St Leonards , NSW , Australia.,e Centre of Research Excellence in Severe Asthma , New Lambton , NSW , Australia
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24
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Cairncross A, Noble PB, McFawn PK. Hyperinflation of bronchi in vitro impairs bronchodilation to simulated breathing and increases sensitivity to contractile activation. Respirology 2018; 23:750-755. [DOI: 10.1111/resp.13271] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 12/19/2017] [Accepted: 01/16/2018] [Indexed: 01/30/2023]
Affiliation(s)
- Alvenia Cairncross
- School of Human Sciences; The University of Western Australia; Perth WA Australia
| | - Peter B. Noble
- School of Human Sciences; The University of Western Australia; Perth WA Australia
- Centre for Neonatal Research and Education; School of Paediatrics and Child Health; Perth WA Australia
| | - Peter K. McFawn
- School of Human Sciences; The University of Western Australia; Perth WA Australia
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25
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Montesantos S, Katz I, Venegas J, Pichelin M, Caillibotte G. The effect of disease and respiration on airway shape in patients with moderate persistent asthma. PLoS One 2017; 12:e0182052. [PMID: 28759656 PMCID: PMC5536319 DOI: 10.1371/journal.pone.0182052] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 07/11/2017] [Indexed: 12/03/2022] Open
Abstract
Computational models of gas transport and aerosol deposition frequently utilize idealized models of bronchial tree structure, where airways are considered a network of bifurcating cylinders. However, changes in the shape of the lung during respiration affect the geometry of the airways, especially in disease conditions. In this study, the internal airway geometry was examined, concentrating on comparisons between mean lung volume (MLV) and total lung capacity (TLC). A set of High Resolution CT images were acquired during breath hold on a group of moderate persistent asthmatics at MLV and TLC after challenge with a broncho-constrictor (methacholine) and the airway trees were segmented and measured. The airway hydraulic diameter (Dh) was calculated through the use of average lumen area (Ai) and average internal perimeter (Pi) at both lung volumes and was found to be systematically higher at TLC by 13.5±9% on average, with the lower lobes displaying higher percent change in comparison to the lower lobes. The average internal diameter (Din) was evaluated to be 12.4±6.8% (MLV) and 10.8±6.3% (TLC) lower than the Dh, for all the examined bronchi, a result displaying statistical significance. Finally, the airway distensibility per bronchial segment and per generation was calculated to have an average value of 0.45±0.28, exhibiting high variability both between and within lung regions and generations. Mixed constriction/dilation patterns were recorded between the lung volumes, where a number of airways either failed to dilate or even constricted when observed at TLC. We conclude that the Dh is higher than Din, a fact that may have considerable effects on bronchial resistance or airway loss at proximal regions. Differences in caliber changes between lung regions are indicative of asthma-expression variability in the lung. However, airway distensibility at generation 3 seems to predict distensibility more distally.
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Affiliation(s)
| | - Ira Katz
- Medical R&D, Air Liquide Santé International, Paris Saclay, France.,Department of Mechanical Engineering, Lafayette College, Easton, PA, United States of America
| | - Jose Venegas
- Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States of America
| | - Marine Pichelin
- Medical R&D, Air Liquide Santé International, Paris Saclay, France
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26
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Mailhot-Larouche S, Lortie K, Marsolais D, Flamand N, Bossé Y. An in vitro study examining the duration between deep inspirations on the rate of renarrowing. Respir Physiol Neurobiol 2017; 243:13-19. [PMID: 28487171 DOI: 10.1016/j.resp.2017.04.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 04/07/2017] [Accepted: 04/29/2017] [Indexed: 12/12/2022]
Abstract
The factors altering the bronchodilatory response to a deep inspiration (DI) in asthma are important to decipher. In this in vitro study, we investigated the effect of changing the duration between DIs on the rate of force recovery post-DI in guinea pig bronchi. The airway smooth muscle (ASM) within the main bronchi were submitted to length oscillation that simulated tidal breathing in different contractile states during 2, 5, 10 or 30min prior to a larger length excursion that simulated a DI. The contractile states of ASM were determined by adding either methacholine or isoproterenol. Irrespective of the contractile state, the duration between DIs neither affected the measured force during length oscillation nor the bronchodilator effect of DI. Contrastingly, the rate of force recovery post-DI in contracted state increased as the duration between DIs decreased. Similar results were obtained with contracted parenchymal strips. These findings suggest that changing the duration between DIs may alter the rate of ASM force recovery post-DI and thereby affect the rate of renarrowing and the duration of the respiratory relief afforded by DI.
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Affiliation(s)
- Samuel Mailhot-Larouche
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Canada
| | - Katherine Lortie
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Canada
| | - David Marsolais
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Canada
| | - Nicolas Flamand
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Canada
| | - Ynuk Bossé
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Canada.
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27
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Mailhot-Larouche S, Lachance M, Bullone M, Henry C, Dandurand RJ, Boulet LP, Laviolette M, King GG, Farah CS, Bossé Y. Assessment of Airway Distensibility by the Forced Oscillation Technique: Reproducible and Potentially Simplifiable. Front Physiol 2017; 8:223. [PMID: 28446881 PMCID: PMC5388760 DOI: 10.3389/fphys.2017.00223] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 03/28/2017] [Indexed: 01/02/2023] Open
Abstract
A non-invasive index of airway distensibility is required to track airway remodeling over time. The forced oscillation technique (FOT) provides such an index by measuring the change in respiratory system conductance at 5 Hz over the corresponding change in lung volume (ΔGrs5/ΔVL). To become useful clinically, this method has to be reproducible and easy to perform. The series of breathing maneuvers required to measure distensibility would be greatly facilitated if the difficulty of breathing below functional residual capacity (FRC) could be precluded and the number of maneuvers could be reduced. The distensibility at lung volumes below FRC is also reduced by several confounders, suggesting that excluding data points below FRC should provide a better surrogate for airway remodeling. The objectives of this study were to investigate the reproducibility of airway distensibility measured by FOT and to assess whether the method could be simplified to increase feasibility. Distensibility was measured at three separate occasions in 13 healthy volunteers. At each visit, three deflationary maneuvers were performed, each consisting of tidal breathing from total lung capacity (TLC) to residual volume by slowly decreasing the end-expiratory volume on each subsequent breath. Distensibility was calculated by using either all data points from TLC to residual volume (RV) or only data points from TLC to FRC for either all three or only the first two deflationary maneuvers. Intra-class correlation coefficients (ICC) were used to assess reproducibility and Bland-Altman analyses were used to assess the level of agreement between the differently calculated values of distensibility. The results indicate that distensibility calculated using all data points is reproducible (ICC = 0.64). Using data points from TLC to FRC slightly improved reproducibility (ICC = 0.68) and increased distensibility by 19.4%, which was expected as distensibility above FRC should not be affected by confounders. Using only data points within the first two maneuvers did not affect reproducibility when tested between TLC and FRC (ICC = 0.66). We conclude that a valuable measure of airway distensibility could potentially be obtained with only two deflationary maneuvers that do not require breathing below FRC. This simplified method would increase feasibility without compromising reproducibility.
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Affiliation(s)
| | - Mélanie Lachance
- Department of Medicine, Quebec Heart and Lung Institute, Université LavalQuebec, QC, Canada
| | - Michela Bullone
- Department of Veterinary Science, University of TurinTurin, Italy
| | - Cyndi Henry
- Department of Medicine, Quebec Heart and Lung Institute, Université LavalQuebec, QC, Canada
| | - Ronald J Dandurand
- Meakins-Christie Laboratories, FOT Unit, Centre for Innovative Medicine, Montreal Chest Institute, McGill University Health Centre and McGill UniversityMontreal, QC, Canada
| | - Louis-Philippe Boulet
- Department of Medicine, Quebec Heart and Lung Institute, Université LavalQuebec, QC, Canada
| | - Michel Laviolette
- Department of Medicine, Quebec Heart and Lung Institute, Université LavalQuebec, QC, Canada
| | - Gregory G King
- Woolcock Institute of Medical ResearchSydney, NSW, Australia.,Sydney Medical School, University of SydneySydney, NSW, Australia.,Department of Respiratory Medicine, Royal North Shore HospitalSydney, NSW, Australia
| | - Claude S Farah
- Woolcock Institute of Medical ResearchSydney, NSW, Australia.,Sydney Medical School, University of SydneySydney, NSW, Australia.,Department of Respiratory Medicine, Concord HospitalSydney, NSW, Australia.,Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Ynuk Bossé
- Department of Medicine, Quebec Heart and Lung Institute, Université LavalQuebec, QC, Canada
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Bhatawadekar SA, Inman MD, Fredberg JJ, Tarlo SM, Lyons OD, Keller G, Yadollahi A. Contribution of rostral fluid shift to intrathoracic airway narrowing in asthma. J Appl Physiol (1985) 2017; 122:809-816. [PMID: 28082337 DOI: 10.1152/japplphysiol.00969.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 01/06/2017] [Accepted: 01/06/2017] [Indexed: 11/22/2022] Open
Abstract
In asthma, supine posture and sleep increase intrathoracic airway narrowing. When humans are supine, because of gravity fluid moves out of the legs and accumulates in the thorax. We hypothesized that fluid shifting out of the legs into the thorax contributes to the intrathoracic airway narrowing in asthma. Healthy and asthmatic subjects sat for 30 min and then lay supine for 30 min. To simulate overnight fluid shift, supine subjects were randomized to receive increased fluid shift out of the legs with lower body positive pressure (LBPP, 10-30 min) or none (control) and crossed over. With forced oscillation at 5 Hz, respiratory resistance (R5) and reactance (X5, reflecting respiratory stiffness) and with bioelectrical impedance, leg and thoracic fluid volumes (LFV, TFV) were measured while subjects were seated and supine (0 min, 30 min). In 17 healthy subjects (age: 51.8 ± 10.9 yr, FEV1/FVC z score: -0.4 ± 1.1), changes in R5 and X5 were similar in both study arms (P > 0.05). In 15 asthmatic subjects (58.5 ± 9.8 yr, -2.1 ± 1.3), R5 and X5 increased in both arms (ΔR5: 0.6 ± 0.9 vs. 1.4 ± 0.8 cmH2O·l-1·s-1, ΔX5: 0.3 ± 0.7 vs. 1.1 ± 0.9 cmH2O·l-1·s-1). The increases in R5 and X5 were 2.3 and 3.7 times larger with LBPP than control, however (P = 0.008, P = 0.006). The main predictor of increases in R5 with LBPP was increases in TFV (r = 0.73, P = 0.002). In asthmatic subjects, the magnitude of increases in X5 with LBPP was comparable to that with posture change from sitting to supine (1.1 ± 0.9 vs. 1.4 ± 0.9 cmH2O·l-1·s-1, P = 0.32). We conclude that in asthmatic subjects fluid shifting from the legs to the thorax while supine contributed to increases in the respiratory resistance and stiffness.NEW & NOTEWORTHY In supine asthmatic subjects, application of positive pressure to the lower body caused appreciable increases in respiratory system resistance and stiffness. Moreover, these changes in respiratory mechanics correlated positively with increase in thoracic fluid volume. These findings suggest that fluid shifts from the lower body to the thorax may contribute to overnight intrathoracic airway narrowing and worsening of asthma symptoms.
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Affiliation(s)
- Swati A Bhatawadekar
- Toronto Rehabilitation Institute-University Health Network, Toronto, Ontario, Canada
| | - Mark D Inman
- Faculty of Medicine (Respirology), McMaster University, Hamilton, Ontario, Canada
| | - Jeffrey J Fredberg
- Department of Environmental Health, Harvard T. H. Chan School of Public Health, Boston, Massachusetts
| | - Susan M Tarlo
- Department of Medicine and Dalla Lana School of Public Health, University of Toronto, Toronto Western Hospital-University Health Network, Toronto, Ontario, Canada
| | - Owen D Lyons
- Department of Medicine (Respirology), University of Toronto, Toronto, Ontario, Canada
| | - Gabriel Keller
- Toronto Rehabilitation Institute-University Health Network, Toronto, Ontario, Canada.,Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; and
| | - Azadeh Yadollahi
- Toronto Rehabilitation Institute-University Health Network, Toronto, Ontario, Canada; .,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
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McGeachie MJ, Yates KP, Zhou X, Guo F, Sternberg AL, Van Natta ML, Wise RA, Szefler SJ, Sharma S, Kho AT, Cho MH, Croteau-Chonka DC, Castaldi PJ, Jain G, Sanyal A, Zhan Y, Lajoie BR, Dekker J, Stamatoyannopoulos J, Covar RA, Zeiger RS, Adkinson NF, Williams PV, Kelly HW, Grasemann H, Vonk JM, Koppelman GH, Postma DS, Raby BA, Houston I, Lu Q, Fuhlbrigge AL, Tantisira KG, Silverman EK, Tonascia J, Strunk RC, Weiss ST. Genetics and Genomics of Longitudinal Lung Function Patterns in Individuals with Asthma. Am J Respir Crit Care Med 2016; 194:1465-1474. [PMID: 27367781 PMCID: PMC5215031 DOI: 10.1164/rccm.201602-0250oc] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Accepted: 06/30/2016] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Patterns of longitudinal lung function growth and decline in childhood asthma have been shown to be important in determining risk for future respiratory ailments including chronic airway obstruction and chronic obstructive pulmonary disease. OBJECTIVES To determine the genetic underpinnings of lung function patterns in subjects with childhood asthma. METHODS We performed a genome-wide association study of 581 non-Hispanic white individuals with asthma that were previously classified by patterns of lung function growth and decline (normal growth, normal growth with early decline, reduced growth, and reduced growth with early decline). The strongest association was also measured in two additional cohorts: a small asthma cohort and a large chronic obstructive pulmonary disease metaanalysis cohort. Interaction between the genomic region encompassing the most strongly associated single-nucleotide polymorphism and nearby genes was assessed by two chromosome conformation capture assays. MEASUREMENTS AND MAIN RESULTS An intergenic single-nucleotide polymorphism (rs4445257) on chromosome 8 was strongly associated with the normal growth with early decline pattern compared with all other pattern groups (P = 6.7 × 10-9; odds ratio, 2.8; 95% confidence interval, 2.0-4.0); replication analysis suggested this variant had opposite effects in normal growth with early decline and reduced growth with early decline pattern groups. Chromosome conformation capture experiments indicated a chromatin interaction between rs4445257 and the promoter of the distal CSMD3 gene. CONCLUSIONS Early decline in lung function after normal growth is associated with a genetic polymorphism that may also protect against early decline in reduced growth groups. Clinical trial registered with www.clinicaltrials.gov (NCT00000575).
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Affiliation(s)
- Michael J. McGeachie
- Channing Division of Network Medicine and
- Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
| | | | - Xiaobo Zhou
- Channing Division of Network Medicine and
- Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - Feng Guo
- Channing Division of Network Medicine and
- Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
| | | | | | - Robert A. Wise
- School of Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Stanley J. Szefler
- National Jewish Health and Research Center, Denver, Colorado
- Children's Hospital Colorado and
| | - Sunita Sharma
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Denver, Colorado
| | - Alvin T. Kho
- Channing Division of Network Medicine and
- Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
- Boston Children’s Hospital, Boston, Massachusetts
| | - Michael H. Cho
- Channing Division of Network Medicine and
- Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - Damien C. Croteau-Chonka
- Channing Division of Network Medicine and
- Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - Peter J. Castaldi
- Channing Division of Network Medicine and
- Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - Gaurav Jain
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, and
| | - Amartya Sanyal
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, and
- School of Biological Sciences, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Ye Zhan
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, and
| | - Bryan R. Lajoie
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, and
| | - Job Dekker
- Howard Hughes Medical Institute, Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts
| | | | - Ronina A. Covar
- National Jewish Health and Research Center, Denver, Colorado
- Children's Hospital Colorado and
- University of Colorado, Denver, Colorado
| | - Robert S. Zeiger
- Department of Pediatrics, University of California at San Diego, La Jolla, California
- Kaiser Permanente Southern California Region, San Diego, California
| | | | - Paul V. Williams
- ASTHMA, Inc., Clinical Research Center and Northwest Asthma & Allergy Center, Seattle, Washington
| | - H. William Kelly
- University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Hartmut Grasemann
- Division of Respiratory Medicine, Department of Pediatrics, The Hospital for Sick Children and University of Toronto, Toronto, Canada
| | | | - Gerard H. Koppelman
- Department of Pediatric Pulmonology and Pediatric Allergology, Beatrix Children’s Hospital, and
| | - Dirkje S. Postma
- Department of Pulmonology, University of Groningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD, Groningen, the Netherlands
| | - Benjamin A. Raby
- Channing Division of Network Medicine and
- Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - Isaac Houston
- Channing Division of Network Medicine and
- Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - Quan Lu
- Program in Molecular and Integrative Physiological Sciences, Departments of Environmental Health and Genetics & Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts; and
| | - Anne L. Fuhlbrigge
- Channing Division of Network Medicine and
- Division of Pulmonary and Critical Care Medicine, Brigham and Women’s Hospital, Boston, Massachusetts
- Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - Kelan G. Tantisira
- Channing Division of Network Medicine and
- Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - Edwin K. Silverman
- Channing Division of Network Medicine and
- Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
| | | | - Robert C. Strunk
- Division of Allergy, Immunology, and Pulmonary Medicine, Washington University School of Medicine, St. Louis, Missouri
| | - Scott T. Weiss
- Channing Division of Network Medicine and
- Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
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Donovan GM. Clustered ventilation defects and bilinear respiratory reactance in asthma. J Theor Biol 2016; 406:166-75. [PMID: 27374171 DOI: 10.1016/j.jtbi.2016.06.035] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 06/08/2016] [Accepted: 06/27/2016] [Indexed: 11/24/2022]
Abstract
Imaging studies of asthmatics typically reveal clustered ventilation patterns, rather than homogeneous ventilation; furthermore, the variation of these clusters suggests that the causes are at least partially dynamic, rather than structural. Theoretical studies have indicated dynamic mechanisms by which homogeneous ventilation solutions lose stability and clustered solutions emerge. At the same time, it has been demonstrated experimentally that respiratory reactance characteristically has a bilinear relationship with lung volume, and that changes to this relationship are indicative of various aspects of disease progression and control. Moreover, the transition point in the bilinear reactance relationship is thought to relate to reopening/recruitment of airway units, and thus may be connected to the bifurcation via which clustered ventilation solutions emerge. In order to investigate this possibility we develop a new model, including both airway-airway coupling and airway-parenchymal coupling, which exhibits both clustered ventilation defects and also a bilinear reactance relationship. Studying this model reveals that (1) the reactance breakpoint is not coincident with the bifurcation; (2) numerous changes to underlying behaviour can alter the reactance breakpoint in ways which mimic the experimental data; and (3) the location of ventilation defects can be a combination of both structural and dynamic factors.
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Affiliation(s)
- Graham M Donovan
- Department of Mathematics, University of Auckland, Private Bag 92019, Auckland, New Zealand.
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Klansky A, Irvin C, Morrison-Taylor A, Ahlstrand S, Labrie D, Haverkamp HC. No effect of elevated operating lung volumes on airway function during variable workrate exercise in asthmatic humans. J Appl Physiol (1985) 2016; 121:89-100. [PMID: 27150833 DOI: 10.1152/japplphysiol.00538.2015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 05/02/2016] [Indexed: 11/22/2022] Open
Abstract
In asthmatic adults, airway caliber fluctuates during variable intensity exercise such that bronchodilation (BD) occurs with increased workrate whereas bronchoconstriction (BC) occurs with decreased workrate. We hypothesized that increased lung mechanical stretch would prevent BC during such variable workrate exercise. Ten asthmatic and ten nonasthmatic subjects completed two exercise trials on a cycle ergometer. Both trials included a 28-min exercise bout consisting of alternating four min periods at workloads equal to 40 % (Low) and 70% (High) peak power output. During one trial, subjects breathed spontaneously throughout exercise (SVT), such that tidal volume (VT) and end-inspiratory lung volume (EILV) were increased by 0.5 and 0.6 liters during the high compared with the low workload in nonasthmatic and asthmatic subjects, respectively. During the second trial (MVT), VT and EILV were maintained constant when transitioning from the high to the low workload. Forced exhalations from total lung capacity were performed during each exercise workload. In asthmatic subjects, forced expiratory volume 1.0 s (FEV1.0) increased and decreased with the increases and decreases in workrate during both SVT (Low, 3.3 ± 0.3 liters; High, 3.6 ± 0.2 liters; P < 0.05) and MVT (Low, 3.3 ± 0.3 liters; High, 3.5 ± 0.2 liters; P < 0.05). Thus increased lung stretch during MVT did not prevent decreases in airway caliber when workload was reduced. We conclude that neural factors controlling airway smooth muscle (ASM) contractile activity during whole body exercise are more robust determinants of airway caliber than the ability of lung stretch to alter ASM actin-myosin binding and contraction.
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Affiliation(s)
- Andrew Klansky
- Johnson State College, Department of Environmental and Health Sciences, Johnson, Vermont; and
| | - Charlie Irvin
- University of Vermont, Vermont Lung Center, Burlington, Vermont
| | - Adriane Morrison-Taylor
- Johnson State College, Department of Environmental and Health Sciences, Johnson, Vermont; and
| | - Sarah Ahlstrand
- Johnson State College, Department of Environmental and Health Sciences, Johnson, Vermont; and
| | - Danielle Labrie
- Johnson State College, Department of Environmental and Health Sciences, Johnson, Vermont; and
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Adam RJ, Hisert KB, Dodd JD, Grogan B, Launspach JL, Barnes JK, Gallagher CG, Sieren JP, Gross TJ, Fischer AJ, Cavanaugh JE, Hoffman EA, Singh PK, Welsh MJ, McKone EF, Stoltz DA. Acute administration of ivacaftor to people with cystic fibrosis and a G551D-CFTR mutation reveals smooth muscle abnormalities. JCI Insight 2016; 1:e86183. [PMID: 27158673 DOI: 10.1172/jci.insight.86183] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Airflow obstruction is common in cystic fibrosis (CF), yet the underlying pathogenesis remains incompletely understood. People with CF often exhibit airway hyperresponsiveness, CF transmembrane conductance regulator (CFTR) is present in airway smooth muscle (ASM), and ASM from newborn CF pigs has increased contractile tone, suggesting that loss of CFTR causes a primary defect in ASM function. We hypothesized that restoring CFTR activity would decrease smooth muscle tone in people with CF. METHODS To increase or potentiate CFTR function, we administered ivacaftor to 12 adults with CF with the G551D-CFTR mutation; ivacaftor stimulates G551D-CFTR function. We studied people before and immediately after initiation of ivacaftor (48 hours) to minimize secondary consequences of CFTR restoration. We tested smooth muscle function by investigating spirometry, airway distensibility, and vascular tone. RESULTS Ivacaftor rapidly restored CFTR function, indicated by reduced sweat chloride concentration. Airflow obstruction and air trapping also improved. Airway distensibility increased in airways less than 4.5 mm but not in larger-sized airways. To assess smooth muscle function in a tissue outside the lung, we measured vascular pulse wave velocity (PWV) and augmentation index, which both decreased following CFTR potentiation. Finally, change in distensibility of <4.5-mm airways correlated with changes in PWV. CONCLUSIONS Acute CFTR potentiation provided a unique opportunity to investigate CFTR-dependent mechanisms of CF pathogenesis. The rapid effects of ivacaftor on airway distensibility and vascular tone suggest that CFTR dysfunction may directly cause increased smooth muscle tone in people with CF and that ivacaftor may relax smooth muscle. FUNDING This work was funded in part from an unrestricted grant from the Vertex Investigator-Initiated Studies Program.
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Affiliation(s)
- Ryan J Adam
- Department of Biomedical Engineering.,Department of Internal Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Katherine B Hisert
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | | | - Brenda Grogan
- National Referral Centre for Adult Cystic Fibrosis, St. Vincent's University Hospital and University College Dublin School of Medicine, Dublin, Ireland
| | - Janice L Launspach
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, USA
| | | | - Charles G Gallagher
- National Referral Centre for Adult Cystic Fibrosis, St. Vincent's University Hospital and University College Dublin School of Medicine, Dublin, Ireland
| | | | - Thomas J Gross
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, USA
| | | | | | - Eric A Hoffman
- Department of Biomedical Engineering.,Department of Radiology, and
| | - Pradeep K Singh
- Department of Medicine, University of Washington, Seattle, Washington, USA.,Department of Microbiology, University of Washington, Seattle, Washington, USA
| | - Michael J Welsh
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, USA.,Department of Molecular Physiology and Biophysics.,Howard Hughes Medical Institute, and.,Pappajohn Biomedical Institute, University of Iowa, Iowa City, Iowa, USA
| | - Edward F McKone
- National Referral Centre for Adult Cystic Fibrosis, St. Vincent's University Hospital and University College Dublin School of Medicine, Dublin, Ireland
| | - David A Stoltz
- Department of Biomedical Engineering.,Department of Internal Medicine, University of Iowa, Iowa City, Iowa, USA.,Department of Molecular Physiology and Biophysics.,Pappajohn Biomedical Institute, University of Iowa, Iowa City, Iowa, USA
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Ansell TK, Noble PB, Mitchell HW, McFawn PK. Pharmacological bronchodilation is partially mediated by reduced airway wall stiffness. Br J Pharmacol 2015; 171:4376-84. [PMID: 24846164 DOI: 10.1111/bph.12781] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 03/31/2014] [Accepted: 04/25/2014] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND AND PURPOSE In asthmatic patients, airflow limitation is at least partly reversed by administration of pharmacological bronchodilators, typically β2 -adrenoceptor agonists. In addition to receptor-mediated bronchodilation, the dynamic mechanical environment of the lung itself can reverse bronchoconstriction. We have now explored the possibility that bronchodilators exert a synergistic effect with oscillatory loads by virtue of reducing airway wall stiffness, and therefore, enhancing the bronchodilatory response to breathing manoeuvres. EXPERIMENTAL APPROACH Whole porcine bronchial segments in vitro were contracted to carbachol and relaxed to the non-specific β-adrenoceptor agonist, isoprenaline, under static conditions or during simulated breathing manoeuvres. KEY RESULTS The bronchodilatory response to isoprenaline was greater during breathing manoeuvres compared with the response under static conditions. As the bronchodilatory response to breathing manoeuvres is dependent upon airway smooth muscle (ASM) strain, and therefore, airway wall stiffness, our findings are likely to be explained by the effect of isoprenaline on reducing airway wall stiffness, which increased ASM strain, producing greater bronchodilation. CONCLUSIONS AND IMPLICATIONS A contribution of reduced airway stiffness and increased ASM strain to the bronchodilator action of isoprenaline is shown, suggesting that oscillatory loads act synergistically with pharmacologically mediated bronchodilation. The implications for the treatment of asthma are that reducing airway wall stiffness represents a potential target for novel pharmacological agents.
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Affiliation(s)
- T K Ansell
- School of Anatomy, Physiology and Human Biology, University of Western Australia, Crawley, WA, Australia
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Le Tuan T, Nguyen NM, Demoulin B, Bonabel C, Nguyen-Thi PL, Ioan I, Schweitzer C, Nguyen HTT, Varechova S, Marchal F. Specific airway resistance in healthy young Vietnamese and Caucasian adults. Respir Physiol Neurobiol 2015; 211:17-21. [PMID: 25796614 DOI: 10.1016/j.resp.2015.03.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 02/25/2015] [Accepted: 03/02/2015] [Indexed: 11/28/2022]
Abstract
In healthy Vietnamese children the respiratory resistance has been suggested to be similar at 110 cm height but larger at 130 cm when compared with data in Caucasians from the literature, suggesting smaller airways in older Vietnamese children (Vu et al., 2008). The hypothesis tested here is whether the difference in airway resistance remains consistent throughout growth, and if it is larger in adult Vietnamese than in Caucasians. Airway resistance and Functional Residual Capacity were measured in healthy young Caucasian and Vietnamese adults in their respective native country using identical equipment and protocols. Ninety five subjects in Vietnam (60 males) and 101 in France (41 males) were recruited. Airway resistance was significantly larger in Vietnamese than in Caucasians and in females than in males, consistent with difference in body dimensions. Specific airway resistance however was not different by ethnicity or gender. The findings do not support the hypothesis that airway size at adult age - once normalized for lung volume - differs between Vietnamese and Caucasians.
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Affiliation(s)
- Thanh Le Tuan
- Department of Physiology, Hanoi Medical University , Hanoi, Vietnam
| | - Ngoc Minh Nguyen
- Department of Physiology, Hanoi Medical University , Hanoi, Vietnam
| | - Bruno Demoulin
- Department of Physiology, University of Lorraine, Vandoeuvre les Nancy, France
| | - Claude Bonabel
- Department of Paediatric Lung Function Testing, University Hospital of Nancy, Children's Hospital, Vandoeuvre les Nancy, France
| | - Phi Linh Nguyen-Thi
- Department of Epidemiology, University Hospital of Nancy, Vandoeuvre les Nancy, France
| | - Iulia Ioan
- Department of Paediatric Lung Function Testing, University Hospital of Nancy, Children's Hospital, Vandoeuvre les Nancy, France
| | - Cyril Schweitzer
- Department of Paediatric Lung Function Testing, University Hospital of Nancy, Children's Hospital, Vandoeuvre les Nancy, France; Department of Epidemiology, University Hospital of Nancy, Vandoeuvre les Nancy, France
| | - H T T Nguyen
- Department of Physiology, Hanoi Medical University , Hanoi, Vietnam
| | - Silvia Varechova
- Department of Paediatric Lung Function Testing, University Hospital of Nancy, Children's Hospital, Vandoeuvre les Nancy, France; Department of Epidemiology, University Hospital of Nancy, Vandoeuvre les Nancy, France
| | - Francois Marchal
- Department of Paediatric Lung Function Testing, University Hospital of Nancy, Children's Hospital, Vandoeuvre les Nancy, France; Department of Epidemiology, University Hospital of Nancy, Vandoeuvre les Nancy, France.
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Ansell TK, McFawn PK, McLaughlin RA, Sampson DD, Eastwood PR, Hillman DR, Mitchell HW, Noble PB. Does smooth muscle in an intact airway undergo length adaptation during a sustained change in transmural pressure? J Appl Physiol (1985) 2015; 118:533-43. [DOI: 10.1152/japplphysiol.00724.2014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
In isolated airway smooth muscle (ASM) strips, an increase or decrease in ASM length away from its current optimum length causes an immediate reduction in force production followed by a gradual time-dependent recovery in force, a phenomenon termed length adaptation. In situ, length adaptation may be initiated by a change in transmural pressure (Ptm), which is a primary physiological determinant of ASM length. The present study sought to determine the effect of sustained changes in Ptm and therefore, ASM perimeter, on airway function. We measured contractile responses in whole porcine bronchial segments in vitro before and after a sustained inflation from a baseline Ptm of 5 cmH2O to 25 cmH2O, or deflation to −5 cmH2O, for ∼50 min in each case. In one group of airways, lumen narrowing and stiffening in response to electrical field stimulation (EFS) were assessed from volume and pressure signals using a servo-controlled syringe pump with pressure feedback. In a second group of airways, lumen narrowing and the perimeter of the ASM in situ were determined by anatomical optical coherence tomography. In a third group of airways, active tension was determined under isovolumic conditions. Both inflation and deflation reduced the contractile response to EFS. Sustained Ptm change resulted in a further decrease in contractile response, which returned to baseline levels upon return to the baseline Ptm. These findings reaffirm the importance of Ptm in regulating airway narrowing. However, they do not support a role for ASM length adaptation in situ under physiological levels of ASM lengthening and shortening.
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Affiliation(s)
- Thomas K. Ansell
- School of Anatomy, Physiology and Human Biology, University of Western Australia, Crawley, Western Australia, Australia
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, Western Australia, Australia
| | - Peter K. McFawn
- School of Anatomy, Physiology and Human Biology, University of Western Australia, Crawley, Western Australia, Australia
| | - Robert A. McLaughlin
- Optical+Biomedical Engineering Laboratory, School of Electrical, Electronic and Computer Engineering, University of Western Australia, Crawley, Western Australia, Australia
| | - David D. Sampson
- Optical+Biomedical Engineering Laboratory, School of Electrical, Electronic and Computer Engineering, University of Western Australia, Crawley, Western Australia, Australia
- Centre for Microscopy, Characterisation and Analysis, University of Western Australia, Crawley, Western Australia, Australia
| | - Peter R. Eastwood
- School of Anatomy, Physiology and Human Biology, University of Western Australia, Crawley, Western Australia, Australia
- West Australian Sleep Disorders Research Institute, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia; and
| | - David R. Hillman
- West Australian Sleep Disorders Research Institute, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia; and
| | - Howard W. Mitchell
- School of Anatomy, Physiology and Human Biology, University of Western Australia, Crawley, Western Australia, Australia
| | - Peter B. Noble
- School of Anatomy, Physiology and Human Biology, University of Western Australia, Crawley, Western Australia, Australia
- Centre for Neonatal Research and Education, School of Paediatrics and Child Health, University of Western Australia, Crawley, Western Australia, Australia
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Aarli BB, Calverley PM, Jensen RL, Eagan TM, Bakke PS, Hardie JA. Variability of within-breath reactance in COPD patients and its association with dyspnoea. Eur Respir J 2014; 45:625-34. [DOI: 10.1183/09031936.00051214] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The forced oscillation technique can identify expiratory flow limitation (EFL) when a large difference in inspiratory and expiratory reactance (ΔXrs) occurs. However, flow limitation can vary from breath to breath, and so we compared a multiple-breath ΔXrs approach to the traditional breath-by-breath assessment of EFL. We investigated the within- and between-day reproducibility and the factors that affect the size of ΔXrs when used as a continuous measurement over multiple breaths. In addition, we examined how multiple-breath ΔXrs relates to the sensation of breathlessness.425 moderate to very severe chronic obstructive pulmonary disease (COPD) patients and 229 controls were included. Spirometry and impedance measurements were performed on a MasterScope CT Impulse Oscillation System.Median ΔXrs approached zero in healthy controls with little variation between measurements. COPD patients generally had higher ΔXrs and higher variability. The COPD patients with ΔXrs >0.1 kPa·L−1·s−1 were prone to be more breathless and had a higher modified Medical Research Council dyspnoea scale score. In controls, the 95th percentile of ΔXrs was as low as 0.07 kPa·L−1·s−1.We describe a new method to assess EFL at a patient level and propose a cut-off, mean ΔXrs >0.1 kPa·L−1·s−1, as a way to identify COPD patients who are more likely to report dyspnoea.
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Chapman DG, Pascoe CD, Lee-Gosselin A, Couture C, Seow CY, Paré PD, Salome CM, King GG, Bossé Y. Smooth Muscle in the Maintenance of Increased Airway Resistance Elicited by Methacholine in Humans. Am J Respir Crit Care Med 2014; 190:879-85. [DOI: 10.1164/rccm.201403-0502oc] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Thompson BR, Westall GP, Paraskeva M, Snell GI. Lung transplantation in adults and children: putting lung function into perspective. Respirology 2014; 19:1097-105. [PMID: 25186813 DOI: 10.1111/resp.12370] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 05/22/2014] [Accepted: 06/20/2014] [Indexed: 01/13/2023]
Abstract
The number of lung transplants performed globally continues to increase year after year. Despite this growing experience, long-term outcomes following lung transplantation continue to fall far short of that described in other solid-organ transplant settings. Chronic lung allograft dysfunction (CLAD) remains common and is the end result of exposure to a multitude of potentially injurious insults that include alloreactivity and infection among others. Central to any description of the clinical performance of the transplanted lung is an assessment of its physiology by pulmonary function testing. Spirometry and the evaluation of forced expiratory volume in 1 s and forced vital capacity, remain core indices that are measured as part of routine clinical follow-up. Spirometry, while reproducible in detecting lung allograft dysfunction, lacks specificity in differentiating the different complications of lung transplantation such as rejection, infection and bronchiolitis obliterans. However, interpretation of spirometry is central to defining the different 'chronic rejection' phenotypes. It is becoming apparent that the maximal lung function achieved following transplantation, as measured by spirometry, is influenced by a number of donor and recipient factors as well as the type of surgery performed (single vs double vs lobar lung transplant). In this review, we discuss the wide range of variables that need to be considered when interpreting lung function testing in lung transplant recipients. Finally, we review a number of novel measurements of pulmonary function that may in the future serve as better biomarkers to detect and diagnose the cause of the failing lung allograft.
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Affiliation(s)
- Bruce Robert Thompson
- Lung Transplant Service, Department of Allergy, Immunology and Respiratory Medicine, The Alfred Hospital, Melbourne, Victoria, Australia; Department of Medicine, Monash University, Melbourne, Victoria, Australia
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Sferrazza Papa GF, Pellegrino GM, Pellegrino R. Asthma and respiratory physiology: putting lung function into perspective. Respirology 2014; 19:960-9. [PMID: 25060051 DOI: 10.1111/resp.12355] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 05/11/2014] [Accepted: 05/26/2014] [Indexed: 10/25/2022]
Abstract
Bronchial asthma is a chronic disease characterized by airway hyperresponsiveness, airway inflammation and remodelling. The hypothesis that the illness is inflammatory in nature has recently been challenged by studies showing that airway smooth muscle (ASM) plays a more important role than previously thought. For example, it is now known that in asthma patients, ASM proliferates more and faster than in healthy subjects, carries intrinsic defects and exhibits impaired relaxation, increased velocity of shortening, plastic adaptation to short length and perturbed equilibrium of actin-to-myosin during cycling. Similar conclusions can be drawn from studies on airway mechanics. For instance, in asthma, abnormal ASM contributes to limiting the response to deep lung stretching and accelerates the return of bronchial tone to baseline conditions, and contributes to increased airway stiffness. Upon stimulation, ASM causes airway narrowing that is heterogeneous across the lung and variable over time. This heterogeneity leads to patchy ventilation. Experimental studies have shown that patchy ventilation may precipitate an asthma attack, and inability to maintain bronchial tone control over time can predict the occurrence of bronchospastic attacks over a matter of a few days. To improve our knowledge on the pathogenesis of asthma, we believe that it is necessary to explore the disease within the framework of the topographical, volume and time domains of the lung that play an important role in setting the severity and progression of the disease. Application of the forced oscillation technique and multiple breath nitrogen washout may, alone or in combination, help address questions unsolvable until now.
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40
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Noble PB, Pascoe CD, Lan B, Ito S, Kistemaker LEM, Tatler AL, Pera T, Brook BS, Gosens R, West AR. Airway smooth muscle in asthma: linking contraction and mechanotransduction to disease pathogenesis and remodelling. Pulm Pharmacol Ther 2014; 29:96-107. [PMID: 25062835 DOI: 10.1016/j.pupt.2014.07.005] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Revised: 07/12/2014] [Accepted: 07/15/2014] [Indexed: 02/07/2023]
Abstract
Asthma is an obstructive airway disease, with a heterogeneous and multifactorial pathogenesis. Although generally considered to be a disease principally driven by chronic inflammation, it is becoming increasingly recognised that the immune component of the pathology poorly correlates with the clinical symptoms of asthma, thus highlighting a potentially central role for non-immune cells. In this context airway smooth muscle (ASM) may be a key player, as it comprises a significant proportion of the airway wall and is the ultimate effector of acute airway narrowing. Historically, the contribution of ASM to asthma pathogenesis has been contentious, yet emerging evidence suggests that ASM contractile activation imparts chronic effects that extend well beyond the temporary effects of bronchoconstriction. In this review article we describe the effects that ASM contraction, in combination with cellular mechanotransduction and novel contraction-inflammation synergies, contribute to asthma pathogenesis. Specific emphasis will be placed on the effects that ASM contraction exerts on the mechanical properties of the airway wall, as well as novel mechanisms by which ASM contraction may contribute to more established features of asthma such as airway wall remodelling.
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Affiliation(s)
- Peter B Noble
- School of Anatomy, Physiology and Human Biology, University of Western Australia, WA, Australia
| | - Chris D Pascoe
- Center for Heart Lung Innovation, University of British Columbia, BC, Canada
| | - Bo Lan
- Center for Heart Lung Innovation, University of British Columbia, BC, Canada; Bioengineering College, Chongqing University, Chongqing, China
| | - Satoru Ito
- Department of Respiratory Medicine, Nagoya University, Aichi, Japan
| | - Loes E M Kistemaker
- Department of Molecular Pharmacology, University of Groningen, The Netherlands
| | - Amanda L Tatler
- Division of Respiratory Medicine, University of Nottingham, United Kingdom
| | - Tonio Pera
- Center for Translational Medicine, Thomas Jefferson University, Philadelphia, PA, USA
| | - Bindi S Brook
- School of Mathematical Sciences, University of Nottingham, United Kingdom
| | - Reinoud Gosens
- Department of Molecular Pharmacology, University of Groningen, The Netherlands
| | - Adrian R West
- Department of Physiology, University of Manitoba, MB, Canada; Biology of Breathing, Manitoba Institute of Child Health, MB, Canada.
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Yoon JW, Shin YH, Jee HM, Chang SJ, Baek JH, Choi SH, Kim HY, Han MY. Useful marker of oscillatory lung function in methacholine challenge test-comparison of reactance and resistance with dose-response slope. Pediatr Pulmonol 2014; 49:521-8. [PMID: 24039248 DOI: 10.1002/ppul.22866] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 06/08/2013] [Indexed: 12/22/2022]
Abstract
BACKGROUND There are few studies focusing on the comparison of resistance (Rrs) and reactance (Xrs) in impulse oscillometry system (IOS) in the bronchial challenge test using dose-response slope (DRS), a quantitative index of bronchial hyperresponsiveness. MATERIAL AND METHODS We conducted a case-control study of 144 asthmatic and 218 non-asthmatic children to compare the diagnostic accuracy of two-point linear DRS for FEV1 , Rrs5 , and Xrs5 (DRS_FEV1 , DRS_Rrs5 , and DRS_Xrs5 ) and assessed various diagnostic cut-off points of provocation concentrations (PC) using receiver operating characteristic (ROC) curves. RESULTS DRS_FEV1 had a stronger correlation with DRS_Xrs5 (r = 0.739, P < 0.001) than with DRS_Rrs5 (r = 0.652, P < 0.001) and the area under the ROC curves of DRS_Xrs5 (0.737) was similar to that of DRS_FEV1 (0.732) and higher than that of DRS_Rrs5 (0.668). The area under the ROC curves in order of greater value was as follows: absolute change of Xrs5 (Abs_Xrs5 ) (0.759) > percent change of FEV1 (Pch_FEV1 ) (0.735) > Pch_Xrs5 (0.727) > Abs_Rrs5 (0.690) > Pch_Rrs5 (0.630). PC78 _Xrs5 and PC0.17 _Xrs5 of IOS showed considerably good sensitivity and specificity comparable to those of PC20 _FEV1 by spirometry. Additional 18 (13%) children who showed normal spirometric measures were identified as asthmatics with the use of IOS. CONCLUSION The utility of the DRS_Xrs5 to differentiate asthmatics from controls was comparable to that of the DRS_FEV1 and better than that of the DRS_Rrs5 . In addition, IOS could detect additional asthmatic patients who did not show positive responses in spirometry.
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Affiliation(s)
- Jung Won Yoon
- Department of Pediatrics, CHA University School of Medicine, Seongnam, Korea
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Lutchen KR. Airway smooth muscle stretch and airway hyperresponsiveness in asthma: have we chased the wrong horse? J Appl Physiol (1985) 2013; 116:1113-5. [PMID: 24265278 DOI: 10.1152/japplphysiol.00968.2013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Kelly VJ, Sands SA, Harris RS, Venegas JG, Brown NJ, Stuart-Andrews CR, King GG, Thompson BR. Respiratory system reactance is an independent determinant of asthma control. J Appl Physiol (1985) 2013; 115:1360-9. [PMID: 23990243 DOI: 10.1152/japplphysiol.00093.2013] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The mechanisms underlying not well-controlled (NWC) asthma remain poorly understood, but accumulating evidence points to peripheral airway dysfunction as a key contributor. The present study tests whether our recently described respiratory system reactance (Xrs) assessment of peripheral airway dysfunction reveals insight into poor asthma control. The aim of this study was to investigate the contribution of Xrs to asthma control. In 22 subjects with asthma, we measured Xrs (forced oscillation technique), spirometry, lung volumes, and ventilation heterogeneity (inert-gas washout), before and after bronchodilator administration. The relationship between Xrs and lung volume during a deflation maneuver yielded two parameters: the volume at which Xrs abruptly decreased (closing volume) and Xrs at this volume (Xrscrit). Lowered (more negative) Xrscrit reflects reduced apparent lung compliance at high lung volumes due, for example, to heterogeneous airway narrowing and unresolved airway closure or near closure above the critical lung volume. Asthma control was assessed via the 6-point Asthma Control Questionnaire (ACQ6). NWC asthma was defined as ACQ6 > 1.0. In 10 NWC and 12 well-controlled subjects, ACQ6 was strongly associated with postbronchodilator (post-BD) Xrscrit (R(2) = 0.43, P < 0.001), independent of all measured variables, and was a strong predictor of NWC asthma (receiver operator characteristic area = 0.94, P < 0.001). By contrast, Xrs measures at lower lung volumes were not associated with ACQ6. Xrscrit itself was significantly associated with measures of gas trapping and ventilation heterogeneity, thus confirming the link between Xrs and airway closure and heterogeneity. Residual airway dysfunction at high lung volumes assessed via Xrscrit is an independent contributor to asthma control.
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Affiliation(s)
- Vanessa J Kelly
- Department of Medicine, Pulmonary and Critical Care Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
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Yoon JW, Hur HY, Jee HM, Baek JH, Kim HY, Shin YH, Han MY. Comparison of bronchial responsiveness assessing dose-response slope between cough-variant asthma and classic asthma in young children. ALLERGY ASTHMA & RESPIRATORY DISEASE 2013. [DOI: 10.4168/aard.2013.1.4.309] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Jung Won Yoon
- Department of Pediatrics, Myongji Hospital, Goyang, Korea
| | - Hye Young Hur
- Department of Pediatrics, CHA Bundang Medical Center, CHA University School of Medicine, Seongnam, Korea
| | - Hye Mi Jee
- Department of Pediatrics, CHA Bundang Medical Center, CHA University School of Medicine, Seongnam, Korea
| | - Ji Hyeon Baek
- Department of Pediatrics, CHA Bundang Medical Center, CHA University School of Medicine, Seongnam, Korea
| | - Hyeong Yoon Kim
- Department of Pediatrics, Bundang Jesaeng Hospital, Seongnam, Korea
| | - Youn Ho Shin
- Department of Pediatrics, CHA Bundang Medical Center, CHA University School of Medicine, Seongnam, Korea
| | - Man Yong Han
- Department of Pediatrics, CHA Bundang Medical Center, CHA University School of Medicine, Seongnam, Korea
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Airway distensibility with lung inflation after allogeneic haematopoietic stem-cell transplantation. Respir Physiol Neurobiol 2012; 184:80-5. [DOI: 10.1016/j.resp.2012.07.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 07/23/2012] [Accepted: 07/24/2012] [Indexed: 11/30/2022]
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Abstract
Noninvasive physiological measurements are reviewed that have been reported in the literature with the specific aim being to study the small airways in lung disease. This has mostly involved at-the-mouth noninvasive measurement of flow, pressure or inert gas concentration, with the intent of deriving one or more indices that are representative of small airway structure and function. While these measurements have remained relatively low-tech, the effort and sophistication increasingly reside with the interpretation of such indices. When aspiring to derive information at the mouth about structural and mechanical processes occurring several airway generations away in a complex cyclically changing cul-de-sac structure, conceptual or semi-quantitative lung models can be valuable. Two assumptions that are central to small airway structure-function measurement are that of an average airway change at a given peripheral lung generation and of a parallel heterogeneity in airway changes. While these are complementary pieces of information, they can affect certain small airways tests in confounding ways. We critically analyzed the various small airway tests under review, while contending that negative outcomes of these tests are probably a true reflection of the fact that no change occurred in the small airways. Utmost care has been taken to not favor one technique over another, given that most current small airways tests still have room for improvement in terms of rendering their content more specific to the small airways. One way to achieve this could consist of the coupling of signals collected at the mouth to spatial information gathered from imaging in the same patient.
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Affiliation(s)
- Sylvia Verbanck
- Respiratory Division, University Hospital UZ Brussel, Brussels, Belgium.
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Aarli BB, Eagan TML, Ellingsen I, Bakke PS, Hardie JA. Reference values for within-breath pulmonary impedance parameters in asymptomatic elderly. CLINICAL RESPIRATORY JOURNAL 2012; 7:245-52. [DOI: 10.1111/j.1752-699x.2012.00312.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Revised: 06/10/2012] [Accepted: 07/06/2012] [Indexed: 11/30/2022]
Affiliation(s)
- Bernt Bøgvald Aarli
- Department of Thoracic Medicine; Haukeland University Hospital; Bergen; Norway
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