Document Detail


Structure-function studies of blood and air capillaries in chicken lung using 3D electron microscopy.
MedLine Citation:
PMID:  20038456     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Avian pulmonary capillaries differ from those of mammals in three important ways. The blood-gas barrier is much thinner, it is more uniform in thickness, and the capillaries are far more rigid when their transmural pressure is altered. The thinness of the barrier is surprising because it predisposes the capillaries to stress failure. A possible mechanism for these differences is that avian pulmonary capillaries, unlike mammalian, are supported from the outside by air capillaries, but the details of the support are poorly understood. To clarify this we studied the blood and air capillaries in chicken lung using transmission electron microscopy (EM) and two relatively new techniques that allow 3D visualization: electron tomography and serial block-face scanning EM. These studies show that the pulmonary capillaries are flanked by epithelial bridges composed of two extremely thin epithelial cells with large surface areas. The junctions of the bridges with the capillary walls show thickening of the epithelial cells and an accumulation of extracellular matrix. Collapse of the pulmonary capillaries when the pressure outside them is increased is apparently prevented by the guy wire-like action of the epithelial bridges. The enlarged junctions between the bridges and the walls could provide a mechanism that limits the hoop stress in the capillary walls when the pressure inside them is increased. The support of the pulmonary capillaries may also be explained by an interdependence mechanism whereby the capillaries are linked to a rigid assemblage of air capillaries. These EM studies show the supporting structures in greater detail than has previously been possible, particularly in 3D, and they allow a more complete analysis of the mechanical forces affecting avian pulmonary capillaries.
Authors:
John B West; Zhenxing Fu; Thomas J Deerinck; Mason R Mackey; James T Obayashi; Mark H Ellisman
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2009-12-28
Journal Detail:
Title:  Respiratory physiology & neurobiology     Volume:  170     ISSN:  1878-1519     ISO Abbreviation:  Respir Physiol Neurobiol     Publication Date:  2010 Feb 
Date Detail:
Created Date:  2010-02-09     Completed Date:  2010-05-05     Revised Date:  2013-05-31    
Medline Journal Info:
Nlm Unique ID:  101140022     Medline TA:  Respir Physiol Neurobiol     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  202-9     Citation Subset:  IM    
Copyright Information:
Copyright 2009 Elsevier B.V. All rights reserved.
Affiliation:
Department of Medicine, and National Center for Microscopy and Imaging Research, University of California San Diego, La Jolla, CA 92093-0623, USA. jwest@ucsd.edu
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MeSH Terms
Descriptor/Qualifier:
Animals
Blood-Air Barrier / ultrastructure*
Capillaries / cytology,  ultrastructure*
Capillary Permeability / physiology
Cell Communication / physiology
Chickens
Electron Microscope Tomography / methods
Epithelial Cells / ultrastructure*
Imaging, Three-Dimensional*
Intercellular Junctions / ultrastructure*
Lung / anatomy & histology,  physiology
Microscopy, Electron, Transmission* / methods
Pulmonary Circulation / physiology
Grant Support
ID/Acronym/Agency:
R01 HL 60968/HL/NHLBI NIH HHS; R01 HL060968-07/HL/NHLBI NIH HHS
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