Salvadego 2016 J Appl Physiol (1985)

Salvadego D, Keramidas ME, Brocca L, Domenis R, Mavelli I, Rittweger J, Eiken O, Mekjavic IB, Grassi B (2016) Separate and combined effects of a 10-d exposure to hypoxia and inactivity on oxidative function in vivo and mitochondrial respiration ex vivo in humans. J Appl Physiol (1985) 121:154-63.

» PMID: 27197861 Open Access

Salvadego D, Keramidas ME, Brocca L, Domenis R, Mavelli I, Rittweger J, Eiken O, Mekjavic IB, Grassi B (2016) J Appl Physiol (1985)

Abstract: An integrative evaluation of oxidative metabolism was carried out in 9 healthy young men (age, 24.1 ± 1.7 yr mean ± SD) before (CTRL) and after a 10-day horizontal bed rest carried out in normoxia (N-BR) or hypoxia (H-BR, FiO₂ = 0.147). H-BR was designed to simulate planetary habitats. Pulmonary O₂ uptake (V_O2) and vastus lateralis fractional O₂ extraction (changes in deoxygenated hemoglobin+myoglobin concentration, Δ[deoxy(Hb+Mb)] evaluated using near-infrared spectroscopy) were evaluated in normoxia and during an incremental cycle ergometer (CE) and one-leg knee extension (KE) exercise (aimed at reducing cardiovascular constraints to oxidative function). Mitochondrial respiration was evaluated ex vivo by high-resolution respirometry in permeabilized vastus lateralis fibers. During CE V_O2peak and Δ[deoxy(Hb+Mb)]peak were lower (P < 0.05) after both N-BR and H-BR than during CTRL; during KE the variables were lower after N-BR but not after H-BR. During CE the overshoot of Δ[deoxy(Hb+Mb)] during constant work rate exercise was greater in N-BR and H-BR than CTRL, whereas during KE a significant difference vs. CTRL was observed only after N-BR. Maximal mitochondrial respiration determined ex vivo was not affected by either intervention. In N-BR, a significant impairment of oxidative metabolism occurred downstream of central cardiovascular O₂ delivery and upstream of mitochondrial function, possibly at the level of the intramuscular matching between O₂ supply and utilization and peripheral O₂ diffusion. Superposition of hypoxia on bed rest did not aggravate, and partially reversed, the impairment of muscle oxidative function in vivo induced by bed rest. The effects of longer exposures will have to be determined.

Copyright © 2016 the American Physiological Society. • Keywords: Hypoxia, Microgravity, Mitochondrial respiration, Muscle inactivity, Oxidative function • Bioblast editor: Kandolf G • O2k-Network Lab: IT Udine Grassi B, IT Udine Mavelli I

Labels: MiParea: Respiration, Exercise physiology;nutrition;life style 

Stress:Cryopreservation, Hypoxia  Organism: Human  Tissue;cell: Skeletal muscle  Preparation: Permeabilized tissue 

Coupling state: LEAK, OXPHOS, ET  Pathway: N, ROX  HRR: Oxygraph-2k 

Labels, 2017-11, BMI, VO2max