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Povzetek: Hypokinesia triggers oxidative stress and accelerates the turnover of the glutathione system via the γ-glutamyl cycle. Our study aimed to identify the regulatory checkpoints controlling intracellular glutathione levels. We measured the intermediate substrates of the γ-glutamyl cycle in erythrocytes from 19 healthy young male volunteers before and during a 10-day experimental bed rest. Additionally, we tracked changes in glutathione levels and specific metabolite ratios up to 21 days of bed rest. Using gas chromatography-mass spectrometry and the internal standard technique, we observed a 9 ± 9% decrease in glutathione levels during the first 5 days of bed rest, followed by an 11 ± 9% increase from the 5th to the 10th day, nearly returning to baseline ambulatory levels. The cysteinyl-glycine-to-glutathione ratio, reflecting γ-glutamyl cyclotransferase activity (a key enzyme in glutathione breakdown), rose by 14 ± 22% in the first 5 days and then fell by 10 ± 14% over the subsequent 5 days, again approaching baseline levels. Additionally, the γ-glutamyl cysteine-to-cysteine ratio, indicative of γ-glutamyl cysteine synthetase activity (crucial for glutathione synthesis), increased by 12 ± 30% on day 5 and by 29 ± 41% on day 10 of bed rest. The results observed on day 21 of bed rest confirm those seen on day 10. By calculating the ratio of product concentration to precursor concentration, we assessed the efficiency of these key enzymes in glutathione turnover. These results were corroborated by directly measuring glutathione synthesis and degradation rates in vivo using stable isotope techniques. Our findings reveal significant changes in glutathione kinetics during the initial days of bed rest and identify potential therapeutic targets for maintaining glutathione levels.
Ključne besede: antioxidant, muscle unloading, glutathion turnover, γ-glutamyl cycle, gamma-glutamyl cycle
Objavljeno v DiRROS: 21.11.2024; Ogledov: 115; Prenosov: 1101
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Ključne besede: skeletal muscle, conference, reports
Objavljeno v DiRROS: 28.10.2024; Ogledov: 116; Prenosov: 72
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Povzetek: Abstract: In recent decades, the rapid spread of various communication media has led to changes in traditional eating habits. In the Mediterranean region, the classic (Mediterranean) dietary pattern has been lost as a result. This has led to a shift in eating habits towards unhealthy eating patterns, which in turn has resulted in an inadequate distribution of body composition. It is known that, among other things, the number of non-communicable diseases increases with the inadequate distribution of body composition. The aim of our study was to examine the level of adherence to the Mediterranean diet (MD) of older adults in the Mediterranean region in relation to specific body composition parameters. This study included 521 older adults with a mean age of 69.6 ± 6.3 years. Body composition was measured using the BIA 101 Anniversary device (Akern s.r.l., Florence, Italy) and adherence to the MD was assessed using the MEDLIFE index questionnaire. This study found significant differences in body composition between males and females. The mean adherence to the MD was 17.0 ± 3.3 points among the participants and there was higher adherence in females (p = 0.002, ηp 2 = 0.019). A multiple linear regression was performed to assess the relationship between the body composition parameters and MD. Multiple linear regression models were significant for reactance, fat mass (%), fat-free mass (%), skeletal muscle index, and total body water (%), with specific individual MEDLIFE items such as the consumption of processed meat, meat, white meat, fruit, vegetables, olive oil and limiting snacks between meals. Moreover, promising correlations were found between certain MD characteristics and BIA parameters, but the overall health effects of the MD remain unclear.
Ključne besede: nutrition, elderly, body composition, healthy ageing, epidemiology
Objavljeno v DiRROS: 28.10.2024; Ogledov: 137; Prenosov: 90
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Povzetek: The concept of muscle quality encompasses both microand macroscopic aspects of muscle architecture and composition and has gained increasing attention with inclusion in the definition of sarcopenia, indicating the significance of muscle quality in evaluating muscle function and strength among older individuals. Muscle quality consists of two main components: neuromuscular and morphological and is often defined as the ratio between the two. The aim of this review is to present currently used methods for assessment of muscle quality with an emphasis on neuromuscular component in older adults. The most used methods for assessing morphological component are imaging techniques, such as magnetic resonance imaging, computed tomography, dualenergy X-ray absorptiometry and non-imaging bioimpedance analysis. In the neuromuscular component upper and lower body strength are assessed with different methods such as hand grip strength, isokinetic lower limb strength and isometric lower limb strength. Currently, there are three proposed muscle quality assessment methods for field or population studies: muscle quality index, ultrasound sarcopenia index and bioimpedancederived phase angle. Despite the exploration of muscle quality through various assessment methods, a consensus on the most appropriate and universally applicable approach has yet to be established.
Ključne besede: ageing, skeletal muscle, ultrasound sarcopenia index, muscle quality index, phase angle
Objavljeno v DiRROS: 13.05.2024; Ogledov: 441; Prenosov: 212
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Povzetek: Background Hormonal doping in recreational sports is a public-health concern. The World Anti-Doping Agency (WADA) promoted the creation of the Athlete Biological Passport, aiming to monitor athlete’s biological variables over time to facilitate indirect detection of doping. Detection tests for anabolic androgenic steroids (AAS) and growth hormone (GH) are available while insulin abuse cannot be revealed. We have determined in recreational bodybuilders the metabolic effects associated with different patterns of hormone abuse. All analyses were conducted using Statistical Package for Social Sciences (SPSS) 21.0 software (SPSS Chicago, IL). Results We have assessed plasma concentrations of selected metabolic markers and fatty acid content in erythrocyte membranes of 92 male bodybuilders and in 45 healthy controls. Hormonal abuse was identified by anonymous questionnaires. 43% (%) of recruited bodybuilders regularly abused hormones, i.e., anabolic androgenic steroids (95%) often associated with GH (30%) and/or insulin (38%). HDL-cholesterol was lower in insulin and/or GH abusers. Alanine (ALT) and aspartic (AST) transaminases were greater in hormone abusing bodybuilders than in non-doping bodybuilders and controls. Insulin doping was selectively associated with increased plasma ALT-to-AST ratio. In erythrocyte membranes, elongase activity (i.e., stearic-to-palmitic ratio) was lower in insulin and/or growth hormone doping, whereas increased Δ-9 desaturase activity (i.e., palmitoleic-to-palmitic ratio) was selectively associated with insulin doping. Conclusions In conclusion, our study demonstrates that insulin and GH abuse are characterized by multiple alterations of specific metabolic markers. Although further studies are needed to test whether longitudinal monitoring of selected metabolic marker such as muscle contraction time, HDL levels, ALT-AST ratio as well as the activities of selected enzymes (e.g. Δ-9 desaturase and elongase), could contribute to the detection of insulin and GH abuse in sport.
Ključne besede: bodybuilders, doping, drug abuse, matabolism
Objavljeno v DiRROS: 03.04.2024; Ogledov: 556; Prenosov: 217
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