Type

Journal Article

Authors

Roberto Bottinelli
Marco Narici
Maria Antonietta Pellegrino
Giuseppe De Vito
Olivier Seynnes
Monica Canepari
Emanuela Longa
Jamie S McPhee
Lorenza Brocca

Subjects

Physiotherapy & Sport

Topics
older men isometric contraction muscle skeletal muscle function post translational modifications up regulation older adults myosin heavy chains

Structure and function of human muscle fibres and muscle proteome in physically active older men. (2017)

Abstract Loss of muscle mass and strength in the growing population of elderly people is a major health concern for modern societies. This condition, termed sarcopenia, is a major cause of falls and of the subsequent increase in morbidity and mortality. Despite numerous studies on the impact of ageing on individual muscle fibres, the contribution of single muscle fibre adaptations to ageing-induced atrophy and functional impairment is still unsettled. The level of physical function and disuse is often associated with ageing. We studied relatively healthy older adults in order to understand the effects of ageing per se without the confounding impact of impaired physical function. We found that in healthy ageing, structural and functional alterations of muscle fibres occur. Protein post-translational modifications, oxidation and phosphorylation contribute to such alterations more than loss of myosin and other muscle protein content. Contradictory results have been reported on the impact of ageing on structure and functions of skeletal muscle fibres, likely to be due to a complex interplay between ageing and other phenomena such as disuse and diseases. Here we recruited healthy, physically and socially active young (YO) and elderly (EL) men in order to study ageing per se without the confounding effects of impaired physical function. In vivo analyses of quadriceps and in vitro analyses of vastus lateralis muscle biopsies were performed. In EL subjects, our results show that (i) quadriceps volume, maximum voluntary contraction isometric torque and patellar tendon force were significantly lower; (ii) muscle fibres went through significant atrophy and impairment of specific force (isometric force/cross-sectional area) and unloaded shortening velocity; (iii) myosin/actin ratio and myosin content in individual muscle fibres were not altered; (iv) the muscle proteome went through quantitative adaptations, namely an up-regulation of the content of several groups of proteins among which were myofibrillar proteins and antioxidant defence systems; (v) the muscle proteome went through qualitative adaptations, namely phosphorylation of several proteins, including myosin light chain-2 slow and troponin T and carbonylation of myosin heavy chains. The present results indicate that impairment of individual muscle fibre structure and function is a major feature of ageing per se and that qualitative adaptations of muscle proteome are likely to be more involved than quantitative adaptations in determining such a phenomenon.
Collections Ireland -> University College Dublin -> PubMed

Full list of authors on original publication

Roberto Bottinelli, Marco Narici, Maria Antonietta Pellegrino, Giuseppe De Vito, Olivier Seynnes, Monica Canepari, Emanuela Longa, Jamie S McPhee, Lorenza Brocca

Experts in our system

1
Giuseppe De Vito
University College Dublin
Total Publications: 47