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Updated: May 20, 2026
10:38
Synthesis and Calibration of Phosphorescent Nanoprobes for Oxygen Imaging in Biological Systems
Published on: March 3, 2010
Oxygen: the poison is in the dose.
1Department of Bioengineering, University of California, San Diego, USA.
Transfusion
|July 19, 2012
Summary
Cell-free hemoglobin (Hb) may cause toxicity by oversupplying oxygen, not just scavenging nitric oxide (NO). This oxygen overload can damage tissues, necessitating modifications to Hb-based oxygen carriers (HBOCs) for safety.
Area of Science:
- Biochemistry
- Physiology
- Toxicology
Background:
- Cell-free hemoglobin (Hb) is implicated in various pathologies, including vasoconstriction and organ damage, particularly in conditions involving hemolysis or Hb-based oxygen carriers (HBOCs).
- The prevailing theory attributes Hb toxicity to scavenging of nitric oxide (NO), but inconsistencies necessitate alternative explanations.
Purpose of the Study:
- To evaluate the hypothesis that cell-free Hb causes toxicity by oversupplying oxygen to tissues, leading to oxygen-related damage.
- To explore the role of oxygen toxicity, potentially via reactive oxygen species and NO destruction, as a mechanism for cell-free Hb adverse effects.
Main Methods:
- Review of existing evidence on tissue oxygen levels, Hb oxygen transport, and protective mechanisms against hyperoxia.
- Analysis of data from in vitro studies, animal models, and clinical trials involving cell-free Hb and HBOCs.
Main Results:
- Cell-free Hb significantly augments oxygen supply to tissues, overwhelming normal protective mechanisms.
- This oxygen oversupply can lead to tissue damage, vasoconstriction, and ischemia, independent of NO scavenging.
- Tissue oxygen levels are tightly regulated and vulnerable to disruption by exogenous cell-free Hb.
Conclusions:
- Cell-free Hb-induced toxicity may stem from oxygen oversupply rather than solely NO scavenging.
- Understanding and controlling oxygen delivery is crucial for developing safe and effective cell-free Hb-based oxygen carriers (HBOCs).
- Novel strategies to limit oxygen supply are needed to mitigate Hb-related vasoconstriction and toxicity.
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