Effect of erythrocyte aggregation on velocity profiles in venules

Jeffrey J. Bishop, Patricia R. Nance, Aleksander S. Popel, Marcos Intaglietta, Paul C. Johnson

Research output: Contribution to journalArticlepeer-review

Abstract

A recent whole organ study in cat skeletal muscle showed that the increase in venous resistance seen at reduced arterial pressures is nearly abolished when the muscle is perfused with a nonaggregating red blood cell suspension. To explore a possible underlying mechanism, we tested the hypothesis that red blood cell aggregation alters flow patterns in vivo and leads to blunted red blood cell velocity profiles at reduced shear rates. With the use of fluorescently labeled red blood cells in tracer quantities and a video system equipped with a gated image intensifier, we obtained velocity profiles in venous nicrovessels (45-75 μm) of rat spinotrapezius muscle at centerline velocities between 0.3 and 14 mm/s (pseudoshear rates 3-120 s-1) under normal (nonaggregating) conditions and after induction of red blood cell aggregation with Dextran 500. Profiles are nearly parabolic (Poiseville flow) over this flow rate range in the absence of aggregation. When aggregation is present, profiles are parabolic at high shear rates and become significantly blunted at pseudoshear rates of 40 s-1 and below. These results indicate a possible mechanisn for increased venous resistance at reduced flows.

Original languageEnglish (US)
Pages (from-to)H222-H236
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume280
Issue number1 49-1
DOIs
StatePublished - 2001

Keywords

  • Blood constitutive equation
  • In vivo blood viscosity
  • In vivo fluorescence microscopy
  • Venous resistance
  • Wall shear stress

ASJC Scopus subject areas

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

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