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

Research output: Contribution to journalArticle

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.

Original languageEnglish (US)
Pages (from-to)1387-1394
Number of pages8
JournalBiochimica et Biophysica Acta - Proteins and Proteomics
Volume1784
Issue number10
DOIs
StatePublished - Oct 1 2008

Keywords

  • Anemia
  • Blood substitute
  • Cerebral blood flow
  • Hemoglobin
  • Oxygen affinity
  • Oxygen transport

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biophysics
  • Biochemistry
  • Molecular Biology

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