Magnesa 2020 Thesis

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Magnesa B (2020) Skeletal muscle mitochondrial oxidative phosphorylation plasticity in two studies on humans: exercise training effect in obese subjects and bed rest effect in healthy subjects. PhD Thesis 81.


Magnesa Benedetta (2020) PhD Thesis

Abstract: Mitochondrion is an important organelle for cells survival being involved in many cellular processes such as energy metabolism and homeostasis, cell division and differentiation, regulation of apoptosis and autophagy, etc. Mitochondrion, due to this role, is able to respond and adapt itself quickly to any perturbation and change of conditions in the different tissues of the human body including skeletal muscle. Thus, mitochondrial plasticity is one of the mechanisms that controls modification due to different physiological conditions such as weight loss or weight gain, exercise and physical inactivity/immobility in skeletal muscle; moreover it represents the capacity of a biologic system to respond to metabolic conditions in relation to the needs of the respective tissues.

In this frame, this PhD Thesis investigated the role and adaptations of mitochondria in two different skeletal muscle pathophysiological models. Exercise is a fundamental tool known to trigger adaptations in mitochondria of skeletal muscle fibres in terms of both of exercise training and of reduced activity/immobility. The present PhD work evaluated the adaptations to exercise, or to the lack of exercise, at the level of mitochondrial oxidative phosphorylation in two conditions particularly relevant for the development of diseases. The first one investigated the effects of two different protocols of exercise training (moderate intensity continuous training and high intensity interval training) in obese patients and the second the effects of 10 days bed rest-induced microgravity and immobility in young healthy volunteers. In both studies, mitochondrial oxidative function was assayed ex vivo in skeletal muscle biopsies by high resolution respirometry using a substrate-uncoupler-inhibitortitration protocol with a substrate combination.

In the first study, obese patients exhibited an increased maximal ADP-stimulated respiration and an increased maximal capacity of the electron transport system after both types of training protocol, confirming the beneficial effect of exercise.

In the second study, no impairment on mitochondrial function in terms of maximal state III respiration and coupling was observed after ten days of bed rest. No alteration in ADP sensitivity was observed after the period of inactivity.

Bioblast editor: Plangger M O2k-Network Lab: IT Udine Grassi B

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

Organism: Human  Tissue;cell: Skeletal muscle  Preparation: Permeabilized tissue 

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