Contribution of Adenosine in the Physiological Changes and Injuries Secondary to Exposure to Extreme Oxygen Pressure in Healthy Subjects

Alain Boussuges (1) , Jeremy Bourenne (1) , Farid Eloufir (1) , Julien Fromonot (1) , Giovanna Mottola (1) , Jean Jacques Risso , Nicolas Vallee , Fabienne Bregeon , Régis Guieu (1)

1 C2VN - Centre recherche en CardioVasculaire et Nutrition = Center for CardioVascular and Nutrition research

Climbers and aviators are exposed to severe hypoxia at high altitudes, whereas divers are exposed to hyperoxia at depth. The aim of this study was to report changes in the adenosinergic system induced by exposure to extreme oxygen partial pressures. At high altitudes, the increased adenosine concentration contributes to brain protection against hypoxia through various mechanisms such as stimulation of glycogenolysis for ATP production, reduction in neuronal energy requirements, enhancement in 2,3-bisphosphoglycerate production, and increase in cerebral blood flow secondary to vasodilation of cerebral arteries. In the context of mountain illness, the increased level of A2AR expression leads to glial dysfunction through neuroinflammation and is involved in the pathogenesis of neurological disorders. Nonetheless, a high level of adenosine concentration can protect against high-altitude pulmonary edema via a decrease in pulmonary arterial pressure. The adenosinergic system is also involved in the acclimatization phenomenon induced by prolonged exposure to altitude hypoxia. During hyperoxic exposure, decreased extracellular adenosine and low A2A receptor expression contribute to vasoconstriction. The resulting decrease in cerebral blood flow is considered a preventive phenomenon against cerebral oxygen toxicity through the decrease in oxygen delivery to the brain. With regard to lung oxygen toxicity, hyperoxia leads to an increase in extracellular adenosine, which acts to preserve pulmonary barrier function. Changes in the adenosinergic system induced by exposure to extreme oxygen partial pressures frequently have a benefit in decreasing the risk of adverse effects.

Mots clés: Adenosine; hypoxia; altitude; hyperoxia; diving

Domaines: Sciences du Vivant [q-bio]

Alain Boussuges, Jeremy Bourenne, Farid Eloufir, Julien Fromonot, Giovanna Mottola, et al.. Contribution of Adenosine in the Physiological Changes and Injuries Secondary to Exposure to Extreme Oxygen Pressure in Healthy Subjects. Biomedicines, 2022, 10 (9), pp.2059. ⟨10.3390/biomedicines10092059⟩. ⟨hal-03922581⟩