Effects of Prolonged Exposure to Hypobaric Hypoxia on Oxidative Stress: Overwintering in Antarctic Concordia Station

Abstract

Concordia Station is the permanent, research station on the Antarctic Plateau at 3230 m. During the eleventh winter-over campaign (DC11-2015; February 2015 to November 2015) at Antarctic Concordia Station, 13 healthy team members were studied and blood samples were collected at six different time points: baseline measurements (T0), performed at sea level before the departure, and during the campaign at 3, 7, 20, 90, and 300 days after arrival at Concordia Station. Reducing the partial pressure of O2 as barometric pressure falls, hypobaric hypoxia (HH) triggers several physiological adaptations. Among the others, increased oxidative stress and enhanced generation of reactive oxygen/nitrogen species (ROS/RNS), resulting in severe oxidative damage, were observed, which can share potential physiopathological mechanisms associated with many diseases. This study characterized the extent and time-course changes after acute and chronic HH exposure, elucidating possible fundamental mechanisms of adaptation. ROS, oxidative stress biomarkers, nitric oxide, and proinflammatory cytokines significantly increased (range 24-135%) during acute and chronic hypoxia exposure (peak 20th day) with a decrease in antioxidant capacity (peak 90th day: -52%). Results suggest that the adaptive response of oxidative stress balance to HH requires a relatively long time, more than 300th days, as all the observed variables do not return to the preexposition level. These findings may also be relevant to patients in whom oxygen availability is limited through disease (i.e., chronic heart and lung and/or kidney disease) and/or during long-duration space missions.

The “ON-OFF” Switching Response of Reactive Oxygen Species in Acute Normobaric Hypoxia: Preliminary Outcome

“…A growing body of evidence indicates that hypoxia decreases both the activity and effectiveness of the antioxidant system, as well as causing increased ROS production with a consequent increase in oxidative damage [ 3 ] to lipids [ 4 , 5 , 6 ], proteins and the DNA [ 5 , 7 ] of cellular compartments [ 8 , 9 , 10 ]. Most studies on the effects of hypoxia have been carried out at high altitude [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ]. However, under such conditions, several factors other than hypoxia could induce oxidative damage; UV radiation, intense physical activity and cold may in fact produce an imbalance between ROS generation and antioxidant protection [ 17 , 18 ].…”

Fertility Impairment after Trekking at High Altitude: A Proof of Mechanisms on Redox and Metabolic Seminal Changes

“…The burden of oxidative stress increases during the time spent at altitude and may even persist for some time upon return to sea levels. In fact, the adaptive process requires a relatively long period of time, as previously reported [ 10 , 32 , 34 ].…”

“…Oxidative stress (OxS) is defined as the excessive production of ROS related to antioxidant defence and can be triggered by endogenous and exogenous factors, among which are expeditions to high altitudes. In fact, exposure to high altitude has been associated with an increase in ROS and related oxidative damage [ 10 , 11 , 30 , 32 ] induced by environmental factors such as hypoxia, cold, UV ray, exposure, and/or physical exercise (daily frequency, low-middle intensity, high volume) [ 30 ]. Moreover, Agarwal et al reported that several extrinsic or environmental factors, such as ionising radiations, alcohol, obesity, deficiencies in antioxidants, varicocele, bacterial/viral infections, toxins, and chemotherapy can induce testicular ROS, causing abnormal spermatogenesis [ 33 ].…”

“…The ROS production rate and antioxidant capacity were determined using the consolidated method [ 10 , 32 , 59 , 60 , 61 , 62 ]. An EPR instrument (E-scan-Bruker BioSpin GmbH, Billerica, MA, USA) X-band (9.3 GHz) was utilised.…”

Evaluation of Oxidative Stress and Metabolic Profile in a Preclinical Kidney Transplantation Model According to Different Preservation Modalities

“…Sample temperature was firstly stabilized and then maintained at 37 °C by a temperature and gas controller “Bio III” unit, interfaced to the spectrometer. From the EPR spectra, relative quantitative determination of ROS production was obtained then converted into absolute concentration by using the stable radical CP* (3-Carboxy-2,2,5,5-tetramethyl-1-pyrrolidinyloxy) as external reference [ 71 , 72 , 73 ].…”