Insensitivity of cerebral oxygen transport to oxygen affinity of hemoglobin-based oxygen carriers

Biochim Biophys Acta. 2008 Oct;1784(10):1387-94. doi: 10.1016/j.bbapap.2008.01.001. Epub 2008 Jan 12.

Abstract

The cerebrovascular effects of exchange transfusion of various cell-free hemoglobins that possess different oxygen affinities are reviewed. Reducing hematocrit by transfusion of a non-oxygen-carrying solution dilates pial arterioles on the brain surface and increases cerebral blood flow to maintain a constant bulk oxygen transport to the brain. In contrast, transfusion of hemoglobins with P50 of 4-34 Torr causes constriction of pial arterioles that offsets the decrease in blood viscosity to maintain cerebral blood flow and oxygen transport. The autoregulatory constriction is dependent on synthesis of 20-HETE from arachidonic acid. This oxygen-dependent reaction is apparently enhanced by facilitated oxygen diffusion from the red cell to the endothelium arising from increased plasma oxygen solubility in the presence of low or high-affinity hemoglobin. Exchange transfusion of recombinant hemoglobin polymers with P50 of 3 and 18 Torr reduces infarct volume from experimental stroke. Cell-free hemoglobins do not require a P50 as high as red blood cell hemoglobin to facilitate oxygen delivery.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Arterioles / physiology
  • Blood Component Transfusion / methods
  • Blood Flow Velocity
  • Brain / metabolism*
  • Cell-Free System / metabolism
  • Cerebrovascular Circulation / physiology*
  • Drug Carriers / metabolism*
  • Hemoglobins / genetics
  • Hemoglobins / metabolism*
  • Humans
  • Hydroxyeicosatetraenoic Acids / metabolism
  • Oxygen / blood*
  • Oxyhemoglobins / administration & dosage
  • Oxyhemoglobins / metabolism*
  • Oxyhemoglobins / therapeutic use
  • Recombinant Proteins / metabolism
  • Solutions
  • Vasoconstriction

Substances

  • Drug Carriers
  • Hemoglobins
  • Hydroxyeicosatetraenoic Acids
  • Oxyhemoglobins
  • Recombinant Proteins
  • Solutions
  • 20-hydroxy-5,8,11,14-eicosatetraenoic acid
  • Oxygen