Document Detail


Structural adaptation of microvascular networks: functional roles of adaptive responses.
MedLine Citation:
PMID:  11514266     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Terminal vascular beds continually adapt to changing demands. A theoretical model is used to simulate structural diameter changes in response to hemodynamic and metabolic stimuli in microvascular networks. Increased wall shear stress and decreased intravascular pressure are assumed to stimulate diameter increase. Intravascular partial pressure of oxygen (PO(2)) is estimated for each segment. Decreasing PO(2) is assumed to generate a metabolic stimulus for diameter increase, which acts locally, upstream via conduction along vessel walls, and downstream via metabolite convection. By adjusting the sensitivities to these stimuli, good agreement is achieved between predicted network characteristics and experimental data from microvascular networks in rat mesentery. Reduced pressure sensitivity leads to increased capillary pressure with reduced viscous energy dissipation and little change in tissue oxygenation. Dissipation decreases strongly with decreased metabolic response. Below a threshold level of metabolic response flow shifts to shorter pathways through the network, and oxygen supply efficiency decreases sharply. In summary, the distribution of vessel diameters generated by the simulated adaptive process allows the network to meet the functional demands of tissue while avoiding excessive viscous energy dissipation.
Authors:
A R Pries; B Reglin; T W Secomb
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  281     ISSN:  0363-6135     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2001 Sep 
Date Detail:
Created Date:  2001-08-21     Completed Date:  2001-09-20     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  H1015-25     Citation Subset:  IM; S    
Affiliation:
Department of Physiology, Freie Universität Berlin, D-14195 Berlin, Germany. pries@zedat.fu-berlin.de
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MeSH Terms
Descriptor/Qualifier:
Adaptation, Physiological / physiology*
Animals
Blood Flow Velocity / physiology
Blood Pressure / physiology
Blood Viscosity / physiology
Computer Simulation
Hemodynamics / physiology
Male
Mesentery / blood supply*
Microcirculation / physiology*
Models, Cardiovascular*
Oxygen / metabolism
Rats
Rats, Wistar
Regional Blood Flow / physiology
Signal Transduction / physiology
Stress, Mechanical
Vascular Patency / physiology
Grant Support
ID/Acronym/Agency:
HL-34555/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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