title: Homothety ratio of airway diameters and site of airway resistance in healthy and COPD subjects.
abstract: Our objective was to evaluate whether a decrease in the homothety ratio (h: diameter of child/parent bronchus, constant over generations) explains the shift in airway resistance toward periphery in chronic obstructive pulmonary disease (COPD). Using a validated computational model of fluid motion, we determined that reduced values of h (<0.76) were associated with a shift in resistance toward periphery. The calculated luminal diameters of terminal bronchioles using normal h (0.80-0.85) or reduced h (0.70-0.75) fitted well with measured micro-CT values obtained by McDonough et al. (N. Engl. J. Med., 2011; 365:1567-75) in control and COPD patients, respectively. A semi-analytic formula of resistance using tracheal dimensions and h was developed, and using experimental data (tracheal area and h from patients [Bokov et al., Respir. Physiol. Neurobiol., 2010; 173:1-10]), we verified the agreement between measured and calculated resistance (r=0.42). In conclusion, the remodeling process of COPD may reduce h and explain the shift in resistance toward lung periphery.
authors.affiliation: Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Physiologie - Clinique de la Dyspnée, Paris, France; Laboratoire Matière et Systèmes Complexes (MSC), UMR 7057 CNRS & Université Paris Diderot, Paris, France; Mosquito Respiratory Research Group, Paris, France.
authors.forename: Plamen
authors.initials: P
authors.lastname: Bokov
authors.affiliation: Laboratoire J.A. Dieudonné (UMR 7351), Université de Nice Sophia-Antipolis/CNRS Parc Valrose, Nice, France.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Mauroy
authors.affiliation: Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Physiologie - Clinique de la Dyspnée, Paris, France; Mosquito Respiratory Research Group, Paris, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Mahut
authors.affiliation: Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Physiologie - Clinique de la Dyspnée, Paris, France; Mosquito Respiratory Research Group, Paris, France; CIC Plurithématique 9201, Hôpital Européen Georges Pompidou, Paris, France; Université Paris Descartes, Paris Sorbonne Cité, Paris, France. Electronic address: christophe.delclaux@egp.aphp.fr.
authors.forename: Christophe
authors.initials: C
authors.lastname: Delclaux
authors.affiliation: Laboratoire Matière et Systèmes Complexes (MSC), UMR 7057 CNRS & Université Paris Diderot, Paris, France.
authors.forename: Patrice
authors.initials: P
authors.lastname: Flaud
mesh_terms: D056151:Airway Remodeling / Q000502:physiology*; D000403:Airway Resistance / Q000502:physiology*; D055745:Bronchioles / Q000503:physiopathology; D003198:Computer Simulation; D006801:Humans; D057446:Hydrodynamics; D008168:Lung / Q000503:physiopathology*; D008954:Models, Biological; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*
keywords: Airway; Chronic obstructive pulmonary disease; Homothety; Remodeling; Resistance