Review
Version 1
Preserved in Portico This version is not peer-reviewed
Carboxyhemoglobin (COHb): Unavoidable Bystander or Protective Player?
Version 1
: Received: 8 May 2023 / Approved: 9 May 2023 / Online: 9 May 2023 (13:36:14 CEST)
A peer-reviewed article of this Preprint also exists.
Carrola, A.; Romão, C.C.; Vieira, H.L.A. Carboxyhemoglobin (COHb): Unavoidable Bystander or Protective Player? Antioxidants 2023, 12, 1198. Carrola, A.; Romão, C.C.; Vieira, H.L.A. Carboxyhemoglobin (COHb): Unavoidable Bystander or Protective Player? Antioxidants 2023, 12, 1198.
Abstract
Carbon monoxide (CO) is a cytoprotective endogenous gas that is ubiquitously produced by the stress response enzyme heme-oxygenase. Being a gas, CO rapidly diffuses through tissues and binds to hemoglobin (Hb) increasing carboxyhemoglobin (COHb) levels. COHb can be formed in the erythrocytes or in plasma from cell-free Hb. Herein, it is discussed whether endogenous COHb is or is not an innocuous and inevitable metabolic waste product and it is hypothesized that COHb has a biological role. In the present review literature data is presented to support this hypothesis based on two main premises: (i) there is no direct correlation between COHb levels and CO toxicity; and (ii) COHb seems to have a direct cytoprotective and antioxidant role in erythrocytes and in hemorrhagic models in vivo. Moreover, CO is also antioxidant by generating COHb, which protects against the pro-oxidant damaging effects of cell free Hb. Up to now COHb has been considered as a sink for both exogenous and endogenous CO generated during CO intoxication or heme metabolism, respectively. Hallmarking COHb as an important molecule with a biological (and eventually beneficial) role is a turning point on CO Biology research, namely in CO intoxication and CO cytoprotection.
Keywords
carbon monoxide; hemoglobin; carboxyhemoglobin; glutathione; antioxidant
Subject
Biology and Life Sciences, Life Sciences
Copyright: This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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