title: Perfusion-related stimuli for compensatory lung growth following pneumonectomy.
abstract: Following pneumonectomy (PNX), two separate mechanical forces act on the remaining lung: parenchymal stress caused by lung expansion, and microvascular distension and shear caused by increased perfusion. We previously showed that parenchymal stress and strain explain approximately one-half of overall compensation; the remainder was presumptively attributed to perfusion-related factors. In this study, we directly tested the hypothesis that perturbation of regional pulmonary perfusion modulates post-PNX lung growth. Adult canines underwent banding of the pulmonary artery (PAB) to the left caudal (LCa) lobe, which caused a reduction in basal perfusion to LCa lobe without preventing the subsequent increase in its perfusion following right PNX while simultaneously exaggerating the post-PNX increase in perfusion to the unbanded lobes, thereby creating differential perfusion changes between banded and unbanded lobes. Control animals underwent sham pulmonary artery banding followed by right PNX. Pulmonary function, regional pulmonary perfusion, and high-resolution computed tomography of the chest were analyzed pre-PNX and 3-mo post-PNX. Terminally, the remaining lobes were fixed for detailed morphometric analysis. Results were compared with corresponding lobes in two control (Sham banding and normal unoperated) groups. PAB impaired the indices of post-PNX extravascular alveolar tissue growth by up to 50% in all remaining lobes. PAB enhanced the expected post-PNX increase in alveolar capillary formation, measured by the prevalence of double-capillary profiles, in both unbanded and banded lobes. We conclude that perfusion distribution provides major stimuli for post-PNX compensatory lung growth independent of the stimuli provided by lung expansion and parenchymal stress and strain.
authors.affiliation: Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; and.
authors.forename: D Merrill
authors.initials: DM
authors.lastname: Dane
authors.affiliation: Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; and.
authors.forename: Cuneyt
authors.initials: C
authors.lastname: Yilmaz
authors.affiliation: Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; and.
authors.forename: Dipendra
authors.initials: D
authors.lastname: Gyawali
authors.affiliation: Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; and.
authors.forename: Roshni
authors.initials: R
authors.lastname: Iyer
authors.affiliation: Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; and.
authors.forename: Priya
authors.initials: P
authors.lastname: Ravikumar
authors.affiliation: Department of Cardiothoracic Surgery, University of Texas Southwestern Medical Center, Dallas, Texas.
authors.forename: Aaron S
authors.initials: AS
authors.lastname: Estrera
authors.affiliation: Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; and Connie.Hsia@utsouthwestern.edu.
authors.forename: Connie C W
authors.initials: CC
authors.lastname: Hsia
mesh_terms: D000818:Animals; D002196:Capillaries / Q000502:physiology; D004285:Dogs; D008168:Lung / Q000502:physiology*; D008176:Lung Volume Measurements / Q000379:methods; D008297:Male; D010477:Perfusion / Q000379:methods; D011013:Pneumonectomy / Q000379:methods; D011651:Pulmonary Artery / Q000502:physiology; D011659:Pulmonary Gas Exchange / Q000502:physiology; D012038:Regeneration / Q000502:physiology*; D013314:Stress, Mechanical; D014057:Tomography, X-Ray Computed / Q000379:methods
keywords: alveolar angiogenesis; lung resection; lung structure and function; pulmonary artery banding; pulmonary blood flow