Carreau 2011 J Cell Mol Med
|Carreau A, El Hafny-Rahbi B, Matejuk A, Grillon C, Kieda C (2011) Why is the partial oxygen pressure of human tissues a crucial parameter? Small molecules and hypoxia. https://doi.org/10.1111/j.1582-4934.2011.01258.x|
» J Cell Mol Med 15:1239-53. PMID:21251211 Open Access
Abstract: Oxygen supply and diffusion into tissues are necessary for survival. The oxygen partial pressure pO2, which is a key component of the physiological state of an organ, results from the balance between oxygen delivery and its consumption. In mammals, oxygen is transported by red blood cells circulating in a well-organized vasculature. Oxygen delivery is dependent on the metabolic requirements and functional status of each organ. Consequently, in a physiological condition, organ and tissue are characterized by their own unique 'tissue normoxia' or 'physioxia' status. Tissue oxygenation is severely disturbed during pathological conditions such as cancer, diabetes, coronary heart disease, stroke, etc., which are associated with decrease in pO2, i.e. 'hypoxia'. In this review, we present an array of methods currently used for assessing tissue oxygenation. We show that hypoxia is marked during tumour development and has strong consequences for oxygenation and its influence upon chemotherapy efficiency. Then we compare this to physiological pO2 values of human organs. Finally we evaluate consequences of physioxia on cell activity and its molecular modulations. More importantly we emphasize the discrepancy between in vivo and in vitro tissue and cells oxygen status which can have detrimental effects on experimental outcome. It appears that the values corresponding to the physioxia are ranging between 11 % and 1 % O2 whereas current in vitro experimentations are usually performed in 19.95 % O2, an artificial context as far as oxygen balance is concerned. It is important to realize that most of the experiments performed in so-called normoxia might be dangerously misleading.
- To distinguish between the various levels of oxygenation, the following terms are currently used: ‘normoxia’ corresponding to atmospheric oxygen pressure, the commonly used oxygen pressure for cell cultures (i.e. around 150 mmHg or 19.95 % oxygen, 20.3 kPa); ‘tissue normoxia’ that we also call ‘physioxia’ for the pO2 measured in different organs in a physiological condition; ‘hypoxia’ representing a pO2 lower than physioxia and indicative for a lack of oxygenation in the tissue.
- Komlódi T, Schmitt S, Zdrazilova L, Donnelly C, Zischka H, Gnaiger E (2022) Oxygen dependence of hydrogen peroxide production in isolated mitochondria and permeabilized cells. MitoFit Preprints 2022 (in prep).
- Komlódi T, Gnaiger E (2022) Discrepancy on oxygen dependence of mitochondrial ROS production - review. MitoFit Preprints 2022 (in prep).
Tissue normoxia, MitoFit 2021 AmR, MitoFit2022Hypoxia, MitoFit 2022 ROS review