Boushel 2013 Abstract MiP2013

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Boushel RC (2013) Convective O2 delivery, diffusion and mitochondrial OXPHOS components of VO2 during exercise in health and disease. Mitochondr Physiol Network 18.08.
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Robert Boushel
MiP2013, Book of Abstracts Open Access

Boushel RC (2013)

Event: MiPNet18.08_MiP2013

Maximal oxygen consumption (VO2) in the organism is defined by the integrated functional capacities of multiple organ systems and characterized by proportionate design of the structural components of the O2 cascade from lung to mitochondria across a wide range of species. Yet, humans exhibit an excess capacity of muscle mitochondrial OXPHOS capacity relative to convective O2 delivery [1,2]. This pattern holds with aging and in chronic diseases such as chronic obstructive lung disease and type 2 diabetes despite a lower expression and/or dysfunction of mitochondria. Muscle diffusional O2 conductance (DO2) is largely dependent on the capillary volume:muscle interface which influences the mean transit time of erythrocytes and off-loading of O2 from haemoglobin at a given p50 and blood flow. Convective O2 delivery remains a dominant factor defining maximal VO2 as revealed by comparison of muscle DO2, mean capillary pO2, and VO2 during exercise engaging small to large muscle groups. The increase in muscle VO2 with endurance training in young, healthy humans is characterized by proportional increases in O2 convection and diffusion, with variable enhancement of mitochondrial OXPHOS capacity, which remains in excess to maximize the pO2 gradient from the red blood cell to cytochrome c oxidase.


O2k-Network Lab: SE Stockholm Boushel RC, CA Vancouver Boushel RC


Labels: MiParea: Respiration, mt-Biogenesis;mt-density, Exercise physiology;nutrition;life style  Pathology: Aging;senescence, COPD, Diabetes, Other 

Organism: Human  Tissue;cell: Skeletal muscle  Preparation: Intact organism, Permeabilized cells, Permeabilized tissue 

Regulation: Oxygen kinetics  Coupling state: OXPHOS  Pathway: N, S, NS  HRR: Oxygraph-2k 

MiP2013 

Affiliations and author contributions

Heart and Circulatory Section, Dept of Biomedical Sciences, University of Copenhagen; Department of Anaesthesia, Bispebjerg Hospital, Denmark. - Email: boushel@sund.ku.dk

References

  1. Boushel RC, Gnaiger E, Calbet JA, Gonzalez-Alonso J, Wright-Paradis C, Sondergaard H, Ara I, Helge JW, Saltin B (2011) Muscle mitochondrial capacity exceeds maximal oxygen delivery in humans. Mitochondrion 11:303-7.
  2. Boushel R, Saltin B (2013) Ex vivo measures of muscle mitochondrial capacity reveal quantitative limits of oxygen delivery by the circulation during exercise. Int J Biochem Cell Biol 45:68-75.