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 language | English (US) |
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Pages (from-to) | 1387-1394 |
Number of pages | 8 |
Journal | Biochimica et Biophysica Acta - Proteins and Proteomics |
Volume | 1784 |
Issue number | 10 |
DOIs | |
State | Published - Oct 2008 |
Keywords
- Anemia
- Blood substitute
- Cerebral blood flow
- Hemoglobin
- Oxygen affinity
- Oxygen transport
ASJC Scopus subject areas
- Analytical Chemistry
- Biophysics
- Biochemistry
- Molecular Biology