Effects of acute and sub-acute hypobaric hypoxia on oxidative stress: a field study in the Alps.
PURPOSE
High altitude results in lower barometric pressure and hence partial pressure of O2 decrease can lead to several molecular and cellular changes, such as generation of reactive oxygen species (ROS). Electron Paramagnetic Resonance technique was adopted in the field, to evaluate the effects of acute and sub-acute hypobaric hypoxia (HH) on ROS production by micro-invasive method. Biological biomarkers, indicators of oxidative stress, renal function and inflammation were investigated too.


METHODS
Fourteen lowlander subjects (mean age 27.3 ± 5.9 years) were exposed to HH at 3269 m s.l. ROS production, related oxidative damage to cellular components, systemic inflammatory response and renal function were determined through blood and urine profile performed at 1st, 2nd, 4th, 7th, and 14th days during sojourn.


RESULTS
Kinetics of changes during HH exposition showed out significant (range p < 0.05-0.0001) increases that at max corresponds to 38% for ROS production rate, 140% for protein carbonyl, 44% for lipid peroxidation, 42% for DNA damage, 200% for inflammatory cytokines and modifications in renal function (assessed by neopterin concentration: 48%). Conversely, antioxidant capacity significantly (p < 0.0001) decreased - 17% at max.


CONCLUSION
This 14 days in-field study describes changes of oxidative-stress biomarkers during HH exposure in lowlanders. The results show an overproduction of ROS and consequent oxidative damage to protein, lipids and DNA with a decrease in antioxidant capacity and the involvement of inflammatory status and a transient renal dysfunction. Exposure at high altitude induces a hypoxic condition during acute and sub-acute phases accompanied by molecular adaptation mechanism indicating acclimatization.
['Mrakic-Sposta|S|S|http://orcid.org/0000-0001-7359-2690', 'Gussoni|M|M|http://orcid.org/0000-0002-5836-7249', 'Dellanoce|C|C|http://orcid.org/0000-0002-0750-6261', 'Marzorati|M|M|http://orcid.org/0000-0003-1093-2162', 'Montorsi|M|M|http://orcid.org/0000-0001-5152-761X', 'Rasica|L|L|http://orcid.org/0000-0001-6943-9845', 'Pratali|L|L|http://orcid.org/0000-0002-1758-5485', "D'Angelo|G|G|http://orcid.org/0000-0002-2064-0801", 'Martinelli|M|M|http://orcid.org/0000-0001-7419-5099', 'Bastiani|L|L|http://orcid.org/0000-0003-3467-7362', 'Di Natale|L|L|http://orcid.org/0000-0002-1031-6573', 'Vezzoli|A|A|http://orcid.org/0000-0002-0277-163X']
D000328:Adult D000532:Altitude Sickness D016207:Cytokines D004249:DNA Damage D005260:Female D006454:Hemoglobins D006801:Humans D008297:Male D019798:Neopterin D018384:Oxidative Stress D050050:Protein Carbonylation
Hypobaric hypoxia Oxidative stress Reactive oxygen species Electron paramagnetic resonance Acclimatization