Estimating oxygen transport resistance of the microvascular wall

Arjun Vadapalli, Roland N. Pittman, And Aleksander S. Popel

Research output: Contribution to journalArticlepeer-review

Abstract

The problem of diffusion of O2 across the endothelial surface in precapillary vessels and its utilization in the vascular wall remains unresolved. To establish a relationship between precapillary release of O2 and vascular wall consumption, we estimated the intravascular flux of O2 on the basis of published in vivo measurements. To interpret the data, we utilized a diffusion model of the vascular wall and computed possible physiological ranges for O2 consumption. We found that many flux values were not consistent with the diffusion model. We estimated the mitochondrial-based maximum O2 consumption of the vascular wall (M(mt)) and a possible contribution to O2 consumption of nitric oxide production by endothelial cells (M(NO)). Many values of O2 consumption predicted from the diffusion model exceeded M(mt) + M(NO). In contrast, reported values of O2 consumption for endothelial and smooth muscle cell suspensions and vascular strips in vitro do not exceed M(mt). We conjecture that most of the reported values of intravascular O2 flux are overestimated, and the likely source is in the experimental estimates of convective O2 transport at upstream and downstream points of unbranched vascular segments.

Original languageEnglish (US)
Pages (from-to)H657-H671
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume279
Issue number2 48-2
DOIs
StatePublished - 2000

Keywords

  • Arterioles
  • Endothelial cell
  • Microcirculation
  • Nitric oxide
  • Oxygen diffusion
  • Smooth muscle cell

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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