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Iskalni niz: "ključne besede" (aging) .

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1.
Absence of an aging-related increase in fibre type grouping in athletes and non-athletes
Mathew Piasecki, Guy A. M. Messa, Joern Rittweger, Jamie McPhee, Erika Koltai, Zsolt Radak, Boštjan Šimunič, Ari Heinonen, Harri Suominen, Marko T. Korhonen, Hans Degens, 2020

Povzetek: The ageing-related loss of muscle mass is thought to be partly attributable to motor neuron loss and motor unit remodelling that result in fibre type grouping. We examined fibre type grouping in 19- to 85-year-old athletes and non-athletes and evaluated to which extent any observed grouping is explained by the fibre type composition of the muscle. Since regular physical activity may stimulate reinnervation, we hypothesised that fibre groups are larger in master athletes than in age-matched non-athletes. Fibre type grouping was assessed in m. vastus lateralis biopsies from 22 young (19-27 years) and 35 healthy older (66-82 years) non-athletes, and 14 young (20-29 years), 51 middle-aged (38%65 years) and 31 older (66-85 years) athletes. An "enclosed fibre" was any muscle fibre of a particular type surrounded by fibres of the same type only. A fibre type group was defined as a group of fibres with at least one enclosed fibre. Only type II fibre cross-sectional area (FCSA) showed an age-related decline that was greater in athletes (p < 0.001) than in non-athletes (p = 0.012). There was no significant age-related effect on fibre group size or fibre group number in athletes or non-athletes, and the observed grouping was similar to that expected from the fibre type composition. At face value these observations do 1) neither show evidence for an age-related loss and remodelling of motor units nor 2) improved reinnervation with regular physical activity, but 3) histological examination may not reveal the full extent of ageing-related motor unit remodelling.
Ključne besede: aging, denervation, fibre type, reinnervation, vastus lateralis
DiRROS - Objavljeno: 24.03.2021; Ogledov: 354; Prenosov: 201
.pdf Celotno besedilo (936,83 KB)

2.
Higher neural demands on stimulus processing after prolonged hospitalization can be mitigated by a cognitively stimulating environment
Uroš Marušič, Rado Pišot, Voyko Kavcic, 2021

Povzetek: Prolonge d periods of complete physical inactivity or bed rest trigger various alterations in the functional and metabolic levels of the human body. However, bed rest-related adaptations of the central nervous system are less known and thoroughly studied. The aim of this study was to investigate brain electrophysiological changes using event-related potentials (ERPs) after 14 days of bed rest and 12 consecutive sessions of computerized cognitive training (CCT). Sixteen older (Mage= 60 years) healthy volunteers were randomly divided into a CCT treatment group and an active control group. All participants performed ERP measurements based on the foveal visual presentation of a circle on a black background before and after bed rest. After 14 days of bed rest, participants in the control group showed increased peak P1 amplitude (p = .012), decreased P1 latency (p = .024), and increased P2 amplitude (p = .036), while the CCT group also showed decreased P1 latency (p = .023) and decreased P2 latency (p = .049). Our results suggest that, even from a central adaptation perspective, prolonged periods of physical inactivity or bed rest trigger additional neural recruitment and should therefore be minimized, and that CCT may serve as a tool to mitigate this. Future research should focus on other aspects of central nervous system adaptation following periods of immobilization/hospitalization to improve our knowledge of infl uence of physical inactivity and its eff ects on cortical activity and to develop appropriate countermeasures to mitigate functional dysregulation.
Ključne besede: aging, physical inactivity, immobilization, electroencephalography, EEG, computerized cognitive training
DiRROS - Objavljeno: 13.05.2021; Ogledov: 271; Prenosov: 173
.pdf Celotno besedilo (820,21 KB)

3.
The aging muscle in experimental bed rest : ǂa ǂsystematic review and meta-analysis
Filippo Giorgio Di Girolamo, Nicola Fiotti, Zoran Milanović, Roberta Situlin, Filippo Mearelli, Pierandrea Vinci, Boštjan Šimunič, Rado Pišot, Marco Vincenzo Narici, Gianni Biolo, 2021

Povzetek: Background: Maintaining skeletal muscle mass and function in aging is crucial for preserving the quality of life and health. An experimental bed rest (BR) protocol is a suitable model to explore muscle decline on aging during inactivity. Objective: The purpose of this systematic review and meta-analysis was, therefore, to carry out an up-to-date evaluation of bed rest, with a specific focus on the magnitude of effects on muscle mass, strength, power, and functional capacity changes as well as the mechanisms, molecules, and pathways involved in muscle decay. Design: This was a systematic review and meta-analysis study. Data sources: We used PubMed, Medline; Web of Science, Google Scholar, and the Cochrane library, all of which were searched prior to April 23, 2020. A manual search was performed to cover bed rest experimental protocols using the following key terms, either singly or in combination: %Elderly Bed rest,% %Older Bed rest,% %Old Bed rest,% %Aging Bed rest,% %Aging Bed rest,% %Bed-rest,% and %Bedrest%. Eligibility criteria for selecting studies: The inclusion criteria were divided into four sections: type of study, participants, interventions, and outcome measures. The primary outcome measures were: body mass index, fat mass, fat-free mass, leg lean mass, cross-sectional area, knee extension power, cytokine pattern, IGF signaling biomarkers, FOXO signaling biomarkers, mitochondrial modulation biomarkers, and muscle protein kinetics biomarkers. Results: A total of 25 studies were included in the qualitative synthesis, while 17 of them were included in the meta-analysis. In total, 118 healthy elderly volunteers underwent 5-, 7-, 10-, or 14-days of BR and provided a brief sketch on the possible mechanisms involved. In the very early phase of BR, important changes occurred in the skeletal muscle, with significant loss of performance associated with a lesser grade reduction of the total body and muscle mass. Meta-analysis of the effect of bed rest on total body mass was determined to be small but statistically significant (ES = %0.45, 95% CI: %0.72 to %0.19, P < 0.001). Moderate, statistically significant effects were observed for total lean body mass (ES = %0.67, 95% CI: %0.95 to %0.40, P < 0.001) after bed rest intervention. Overall, total lean body mass was decreased by 1.5 kg, while there was no relationship between bed rest duration and outcomes (Z = 0.423, p = 672). The meta-analyzed effect showed that bed rest produced large, statistically significant, effects (ES = %1.06, 95% CI: %1.37 to %0.75, P < 0.001) in terms of the knee extension power. Knee extension power was decreased by 14.65 N/s. In contrast, to other measures, meta-regression showed a significant relationship between bed rest duration and knee extension power (Z = 4.219, p < 0.001). Moderate, statistically significant, effects were observed after bed rest intervention for leg muscle mass in both old (ES = %0.68, 95% CI: %0.96 to %0.40, P < 0.001) and young (ES = %0.51, 95% CI: %0.80 to %0.22, P < 0.001) adults. However, the magnitude of change was higher in older (MD = %0.86 kg) compared to younger (MD = %0.24 kg) adults. Conclusion: Experimental BR is a suitable model to explore the detrimental effects of inactivity in young adults, old adults, and hospitalized people. Changes in muscle mass and function are the two most investigated variables, and they allow for a consistent trend in the BR-induced changes. Mechanisms underlying the greater loss of muscle mass and function in aging, following inactivity, need to be thoroughly investigated.
Ključne besede: bed rest, aging, muscles, muscle physiopathology, muscle function
DiRROS - Objavljeno: 26.08.2021; Ogledov: 111; Prenosov: 65
.pdf Celotno besedilo (1,32 MB)

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