Structural adaptation of microvascular networks: Functional roles of adaptive responses

A. R. Pries, B. Reglin, Timothy W Secomb

Research output: Contribution to journalArticle

121 Citations (Scopus)

Abstract

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 (PO2) is estimated for each segment. Decreasing PO2 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.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume281
Issue number3 50-3
StatePublished - 2001

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Microvessels
Pressure
Oxygen
Convection
Mesentery
Partial Pressure
Blood Vessels
Theoretical Models
Hemodynamics

Keywords

  • Conducted response
  • Mathematical modeling
  • Oxygen transport
  • Pressure
  • Shear stress

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

Cite this

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