In vivo evaluation of the effectiveness of bronchial thermoplasty with computed tomography

1 Department of Environmental Health Sciences, Johns Hopkins University, Bloomberg School of Public Health, Baltimore, Maryland; and 2 Asthmatx, Mountain View, California Submitted 26 October 2004 ; accepted in final form 9 January 2005 A recent study has reported that the application of thermal ene...

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Veröffentlicht in:Journal of applied physiology (1985) 2005-05, Vol.98 (5), p.1603-1606
Hauptverfasser: Brown, Robert H, Wizeman, William, Danek, Christopher, Mitzner, Wayne
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Sprache:eng
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Zusammenfassung:1 Department of Environmental Health Sciences, Johns Hopkins University, Bloomberg School of Public Health, Baltimore, Maryland; and 2 Asthmatx, Mountain View, California Submitted 26 October 2004 ; accepted in final form 9 January 2005 A recent study has reported that the application of thermal energy delivered through a bronchoscope (bronchial thermoplasty) impairs the ability of airway smooth muscle to shorten in response to methacholine (MCh)(Danek CJ, Lombard CM, Dungworth DL, Cox PG, Miller JD, Biggs MJ, Keast TM, Loomas BE, Wizeman WJ, Hogg JC, and Leff AR. J Appl Physiol 97: 1946–1953, 2004). If such a technique is successful, it has the potential to serve as a therapy to attenuate airway narrowing in asthmatic subjects regardless of the initiating cause that stimulates the smooth muscle. In the present study, we have applied high-resolution computed tomography to accurately quantify the changes in airway area before and after a standard MCh aerosol challenge in airways treated with bronchial thermoplasty. We studied a total of 193 airways ranging from 2 to 15 mm in six dogs. These were divided into treated and control populations. The MCh dose-response curves in untreated airways and soon-to-be-treated airways were superimposable. In contrast, the dose-response curves in treated airways were shifted upward at all points, showing a significantly decreased sensitivity to MCh at both 2 and 4 wk posttreatment. These results thus show that treated airways have significantly increased luminal area at any dose of inhaled MCh compared with untreated airways. The work in this study thus supports the underlying concept that impairing the smooth muscle may be an effective treatment for asthma. asthma; airway smooth muscle; lung mechanics; airway structure Address for correspondence: W. Mitzner, Dept. of Environmental Health Sciences, Johns Hopkins Medical Institutions, 615 N. Wolfe St., Baltimore, MD 21205 (E-mail: wmitzner{at}jhsph.edu )
ISSN:8750-7587
1522-1601
DOI:10.1152/japplphysiol.01210.2004