Chronic hypoxia accentuates dysanaptic lung growth

Conrado J. Llapur, Myriam R. Martinez, Pedro T. Grassino, Ana Stok, Hector H. Altieri, Federico Bonilla, Maria M. Caram, Natasha M. Krowchuk, Miranda Kirby, Harvey O. Coxson, Robert Tepper

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

Rationale: 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. Objectives: To assess the effect of chronic hypoxia on lung growth using in vivo high-resolution computed tomography measurements. Methods: 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. Measurements and Main Results: 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. Conclusions: 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.

Original languageEnglish (US)
Pages (from-to)327-332
Number of pages6
JournalAmerican Journal of Respiratory and Critical Care Medicine
Volume194
Issue number3
DOIs
StatePublished - Aug 1 2016

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Keywords

  • Airway size
  • Altitude
  • Lung density
  • Lung volume
  • Pulmonary diffusion capacity

ASJC Scopus subject areas

  • Medicine(all)
  • Pulmonary and Respiratory Medicine
  • Critical Care and Intensive Care Medicine

Cite this

Llapur, C. J., Martinez, M. R., Grassino, P. T., Stok, A., Altieri, H. H., Bonilla, F., Caram, M. M., Krowchuk, N. M., Kirby, M., Coxson, H. O., & Tepper, R. (2016). Chronic hypoxia accentuates dysanaptic lung growth. American Journal of Respiratory and Critical Care Medicine, 194(3), 327-332. https://doi.org/10.1164/rccm.201509-1851OC