title: Chronic Hypoxia Accentuates Dysanaptic Lung Growth.
abstract: Adults born and raised at high altitudes have larger lung volumes and greater pulmonary diffusion capacity compared with adults at low altitude; however, it remains unclear whether the air and tissue volumes have comparable increases and whether there is a difference in airway size.
  
  
  
  To assess the effect of chronic hypoxia on lung growth using in vivo high-resolution computed tomography measurements.
  
  
  
  Healthy adults born and raised at moderate altitude (2,000 m above sea level; n = 19) and at low altitude (400 m above sea level; n = 23) underwent high-resolution computed tomography. Differences in total lung, air, and tissue volume, mean lung density, as well as airway lumen and wall areas in anatomically matched airways were compared between groups.
  
  
  
  No significant differences for age, sex, weight, or height were found between the two groups (P > 0.05). In a multivariate regression model, altitude was a significant contributor for total lung volume (P = 0.02), air volume (P = 0.03), and tissue volume (P = 0.03), whereby the volumes were greater for the moderate- versus the low-altitude group. However, altitude was not a significant contributor for mean lung density (P = 0.35) or lumen and wall areas in anatomically matched segmental, subsegmental, and subsubsegmental airways.
  
  
  
  Our findings suggest that the adult lung did not increase lung volume later in life by expansion of an existing number of alveoli, but rather from increased alveolarization early in life. In addition, chronic hypoxia accentuates dysanaptic lung growth by increasing the lung parenchyma but not the airways.
authors: 1 Department of Pediatric Pulmonology and.|2 Cátedra de Metodología de la Investigación.
authors: Conrado J
authors: CJ
authors: Llapur
authors: 1 Department of Pediatric Pulmonology and.
authors: Myriam R
authors: MR
authors: Martínez
authors: 3 Department of Radiology, Hospital del Niño Jesús, Tucumán, Argentina.|4 Cátedra de Diagnostico por Imágenes.
authors: Pedro T
authors: PT
authors: Grassino
authors: 5 Instituto de Patologías Respiratorias Tucumán, Tucumán, Argentina.
authors: Ana
authors: A
authors: Stok
authors: 7 Cátedra de Clínica Medica, and.|6 Department of Pulmonology, Hospital Centro de Salud Zenón Santillán, Tucumán, Argentina.
authors: Héctor H
authors: HH
authors: Altieri
authors: 8 Instituto Superior de Investigaciones Biológicas, Universidad Nacional de Tucumán, Tucumán, Argentina.
authors: Federico
authors: F
authors: Bonilla
authors: 9 Cátedra de Histología, Facultad de Medicina, Universidad Nacional de Tucumán, Tucumán, Argentina.|10 Hospital Eva Perón, Tucumán, Argentina.
authors: María M
authors: MM
authors: Caram
authors: 11 Centre for Heart Lung Innovation, St. Paul's Hospital and the University of British Columbia, Vancouver, British Columbia, Canada; and.
authors: Natasha M
authors: NM
authors: Krowchuk
authors: 11 Centre for Heart Lung Innovation, St. Paul's Hospital and the University of British Columbia, Vancouver, British Columbia, Canada; and.
authors: Miranda
authors: M
authors: Kirby
authors: 11 Centre for Heart Lung Innovation, St. Paul's Hospital and the University of British Columbia, Vancouver, British Columbia, Canada; and.
authors: Harvey O
authors: HO
authors: Coxson
authors: 12 Herman B. Wells Center for Pediatric Research, Section of Pulmonology, James Whitcomb Riley Hospital for Children, Indiana University School of Medicine, Indianapolis, Indiana.
authors: Robert S
authors: RS
authors: Tepper
mesh_terms: D000328:Adult; D000531:Altitude; D001118:Argentina; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D008168:Lung / Q000033:anatomy & histology* / Q000502:physiology*; D008297:Male; D009929:Organ Size; D012129:Respiratory Function Tests / Q000706:statistics & numerical data; D013147:Spirometry / Q000706:statistics & numerical data; D013990:Tidal Volume / Q000502:physiology; D014057:Tomography, X-Ray Computed
keywords: airway size; altitude; lung density; lung volume; pulmonary diffusion capacity