title: Persistent structural adaptation in the lungs of guinea pigs raised at high altitude.
abstract: Laboratory guinea pigs raised at high altitude (HA, 3800 m) for up to 6 mo exhibit enhanced alveolar growth and remodeling (Hsia et al., 2005. Resp. Physiol. Neurobiol. 147, 105-115). To determine whether initial HA-induced structural enhancement persists following return to intermediate altitude (IA), we raised weanling guinea pigs at (a) HA for 11-12 mo, (b) IA (1200 m) for 11-12 mo, and (c) HA for 4 mo followed by IA for 7-8 mo (HA-to-IA). Morphometric analysis was performed under light and electron microscopy. Body weight and lung volume were similar among groups. Prolonged HA residence increased alveolar epithelium and interstitium volumes while reducing alveolar-capillary blood volume. The HA-induced gains in type-1 epithelium volume and alveolar surface area were no longer present following return to IA whereas volume increases in type-2 epithelium and interstitium and the reduction in alveolar duct volume persisted. Results demonstrate persistent augmentation of some but not all aspects of lung structure throughout prolonged HA residence, with partial reversibility following re-acclimatization to IA.
authors.affiliation: Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9034, United States. Electronic address: Priya.Ravikumar@utsouthwestern.edu.
authors.forename: Priya
authors.initials: P
authors.lastname: Ravikumar
authors.affiliation: Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9034, United States.
authors.forename: Dennis J
authors.initials: DJ
authors.lastname: Bellotto
authors.affiliation: Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9034, United States.
authors.forename: Connie C W
authors.initials: CC
authors.lastname: Hsia
mesh_terms: D000064:Acclimatization / Q000502:physiology*; D000367:Age Factors; D000531:Altitude; D000704:Analysis of Variance; D000818:Animals; D015331:Cohort Studies; D004848:Epithelium / Q000648:ultrastructure; D005260:Female; D006168:Guinea Pigs; D008168:Lung / Q000502:physiology* / Q000648:ultrastructure; D008297:Male; D011650:Pulmonary Alveoli / Q000166:cytology; D011652:Pulmonary Circulation / Q000502:physiology*; D011659:Pulmonary Gas Exchange; D015656:Respiratory Mechanics / Q000502:physiology*; D013997:Time Factors
keywords: Alveolar duct; Alveolar surface area; Alveolar tissue volume; Blood-gas diffusion barrier; Chronic hypoxia; Gas exchange; Lung growth