Now showing 1 - 10 of 33
  • Publication
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    Resistance training does not increase myocellular garbage dumps: A pilot study on lipofuscin in skeletal muscle fibers of resistance trained young men
    (2024-01-31)
    Jacko, Daniel 
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    Masur, Lukas 
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    Schaaf, Kirill 
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    Zacher, Jonas 
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    Marées, Markus de 
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    Bloch, Wilhelm 
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    Lipofuscin (LF) is an intracellular aggregate associated with proteostatic impairments, especially prevalent in nondividing skeletal muscle fibers. Reactive oxygen species (ROS) drive LF-formation. Resistance training (RT) improves muscle performance but also increases ROS production, potentially promoting LF-formation. Thus, we aimed to investigate if RT of a mesocycle duration increases LF-formation in type-I and II muscle fibers and whether RT increases the antioxidant capacity (AOC) in terms of SOD1 and SOD2 content. An intervention group (IG) performed 14 eccentrically accented RT-sessions within 7 weeks. Vastus lateralis muscle biopsies were collected before and after the intervention from IG as well as from a control group (CG) which refrained from RT for the same duration. LF was predominantly found near nuclei, followed by membrane-near and a minor amount in the fiber core, with corresponding spot sizes. Overall, LF-content was higher in type-I than type-II fibers (p < 0.05). There was no increase in LF-content in type-I or IIA fibers, neither for the IG following RT nor for the CG. The same is valid for SOD1/2. We conclude that, in healthy subjects, RT can be safely performed, without adverse effects on increased LF-formation.
      7
  • Publication
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    Increased type-I interferon level is associated with liver damage and fibrosis in primary sclerosing cholangitis
    (2024)
    Salzmann, Rebekka J.S. 
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    Krötz, Christina 
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    Mocan, Tudor 
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    Mocan, Lavinia P. 
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    Grapa, Cristiana 
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    Rottmann, Sophia 
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    Reichelt, Ramona 
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    Keller, Cindy M. 
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    Langhans, Bettina 
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    ; ; ; ;
    Krawczyk, Marcin 
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    Milkiewicz, Piotr 
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    Sparchez, Zeno 
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    Lammert, Frank 
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    Gonzalez-Carmona, Maria A. 
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    Willms, Arnulf 
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    Strassburg, Christian P. 
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    Kornek, Miroslaw T. 
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    Dold, Leona 
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    Lukacs-Kornek, Veronika 
    Background: The level of type-I interferons (IFNs) in primary sclerosing cholangitis (PSC) was investigated to evaluate its association with disease activity and progression. Methods: Bioactive type-I IFNs were evaluated in a murine model of PSC and human patients’ sera using a cell-based reporter assay and ELISA techniques. In total, 57 healthy participants, 71 PSC, and 38 patients with primary biliary cholangitis were enrolled in this study. Results: Bioactive type-I IFNs were elevated in the liver and serum of multidrug resistance protein 2–deficient animals and showed a correlation with the presence of CD45+ immune cells and serum alanine transaminase levels. Concordantly, bioactive type-I IFNs were elevated in the sera of patients with PSC as compared to healthy controls (sensitivity of 84.51%, specificity of 63.16%, and AUROC value of 0.8267). Bioactive IFNs highly correlated with alkaline phosphatase (r=0.4179, p<0.001), alanine transaminase (r=0.4704, p<0.0001), and gamma-glutamyl transpeptidase activities (r=0.6629, p<0.0001) but not with serum bilirubin. In addition, patients with PSC with advanced fibrosis demonstrated significantly higher type-I IFN values. Among the type-I IFN subtypes IFNα, β and IFNω could be detected in patients with PSC with IFNω showing the highest concentration among the subtypes and being the most abundant among patients with PSC. Conclusions: The selectively elevated bioactive type-I IFNs specifically the dominating IFNω could suggest a novel inflammatory pathway that might also have a hitherto unrecognized role in the pathomechanism of PSC.
      38
  • Publication
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    A modified formula using energy system contributions to calculate pure maximal rate of lactate accumulation during a maximal sprint cycling test.
    (2023-04)
    Yang, Woo-Hwi 
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    Park, So-Young 
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    Kim, Taenam 
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    Jeon, Hyung-Jin 
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    Heine, Oliver 
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    Purpose: This study aimed at comparing previous calculating formulas of maximal lactate accumulation rate (νLa.max) and a modified formula of pure νLa.max (PνLa.max) during a 15-s all-out sprint cycling test (ASCT) to analyze their relationships. Methods: Thirty male national-level track cyclists participated in this study (n = 30) and performed a 15-s ASCT. The anaerobic power output (Wpeak and Wmean), oxygen uptake, and blood lactate concentrations (La−) were measured. These parameters were used for different calculations of νLa.max and three energy contributions (phosphagen, WPCr; glycolytic, WGly; and oxidative, WOxi). The PνLa.max calculation considered delta La−, time until Wpeak (tPCr−peak), and the time contributed by the oxidative system (tOxi). Other νLa.max levels without tOxi were calculated using decreasing time by 3.5% from Wpeak (tPCr −3.5%) and tPCr−peak. Results: The absolute and relative WPCr were higher than WGly and WOxi (p < 0.0001, respectively), and the absolute and relative WGly were significantly higher than WOxi (p < 0.0001, respectively); νLa.max (tPCr −3.5%) was significantly higher than PνLa.max and νLa.max (tPCr−peak), while νLa.max (tPCr−peak) was lower than PνLa.max (p < 0.0001, respectively). PνLa.max and νLa.max (tPCr−peak) were highly correlated (r = 0.99; R2 = 0.98). This correlation was higher than the relationship between PνLa.max and νLa.max (tPCr −3.5%) (r = 0.87; R2 = 0.77). νLa.max (tPCr−peak), PνLa.max, and νLa.max (tPCr −3.5%) were found to correlate with absolute Wmean and WGly. Conclusion: PνLa.max as a modified calculation of νLa.max provides more detailed insights into the inter-individual differences in energy and glycolytic metabolism than νLa.max (tPCr−peak) and νLa.max (tPCr −3.5%). Because WOxi and WPCr can differ remarkably between athletes, implementing their values in PνLa.max can establish more optimized individual profiling for elite track cyclists.
      6
  • Publication
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    Diagnostics of VLamax and Glycolytic Energy Contribution Indicate Individual Characteristics of Anaerobic Glycolytic Energy Metabolism Contributing to Rowing Performance
    (2023-02) ;
    Park, Soyoung 
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    Wawer, Corinna 
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    Theis, Christian 
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    Yang, Woo-Hwi 
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    The diagnostic of anaerobic glycolytic metabolism which play a subordinate role in elite rowing and parameters such as maximum lactate accumulation rate (νLa.max) have thus far not been associated with ergometer rowing performance. The aim of the study was to quantify the glycolytic energy metabolism (WGly) during a 2000 m ergometer rowing time trial (RTT) and νLa.max during a 10 s maximum ergometer rowing sprint test (RST) and to unravel associations between those variables and RTT performance. Combined post-exercise lactate measurements and oxygen uptake after RST and RTT were used to determine νLa.max and glycolytic energy contribution (WGly) in seven male and three female German U 23 national rowers (N = 10, 19.8 ± 0.9 years, 183.2 ± 7.0 cm height, 79.9 ± 13.3 kg body mass, 16.4 ± 5.1 % body fat). WGly during RTT ranged from 7 to 15.5% and νLa.max between 0.25 and 0.66 mmol∙L−1∙s−1. νLa.max correlated with WGly (p < 0.05, r = 0.74) and the mechanical power output (W) for the first 300 m (300first) during RTT (p < 0.05, r = 0.67). νLa.max further correlated with ∆300first−last (W) for the first and last 300 m (300last) during RTT (p < 0.01, r = 0.87) and also within the subgroup of male rowers. νLa.max displays a wide spectrum of individual differences in rowers. Due to this and its correlation to specific phases of RTT, it contributes to an individual energetic performance profile in rowing. Future studies must undermine the role of νLa.max for exercise performance and whether it serves as a marker that can be specifically targeted for a training-induced increase or decrease.
      6
  • Publication
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    Enhanced capacity for CaMKII signaling mitigates calcium release related contractile fatigue with high intensity exercise
    (2023)
    Flück, Martin 
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    Sanchez, Colline 
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    Jacquemond, Vincent 
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    Berthier, Christine 
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    Giraud, Marie-Noëlle 
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    Jacko, Daniel 
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    Baan, Guus 
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    Jaspers, Richard T. 
      5
  • Publication
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    Resistance exercise: a mighty tool that adapts, destroys, rebuilds and modulates the molecular and structural environment of skeletal muscle
    (2023) ;
    So-Young, Park 
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    Schaaf, Kirill 
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    Yang, Woo-Hwi 
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    Theis, Christian 
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    Jacko, Daniel 
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    Purpose: Skeletal muscle regulates health and performance by maintaining or increasing strength and muscle mass. Although the molecular mechanisms in response to resistance exercise (RE) significantly target the activation of protein synthesis, a plethora of other mechanisms and structures must be involved in orchestrating the communication, repair, and restoration of homeostasis after RE stimulation. In practice, RE can be modulated by variations in intensity, continuity and volume, which affect molecular responses and skeletal muscle adaptation. Knowledge of these aspects is important with respect to planning of training programs and assessing the impact of RE training on skeletal muscle. Methods: In this narrative review, we introduce general aspects of skeletal muscle substructures that adapt in response to RE. We further highlighted the molecular mechanisms that control human skeletal muscle anabolism, degradation, repair and memory in response to acute and repeated RE and linked these aspects to major training variables. Results: Although RE is a key stimulus for the activation of skeletal muscle anabolism, it also induces myofibrillar damage. Nevertheless, to increase muscle mass accompanied by a corresponding adaptation of the essential substructures of the sarcomeric environment, RE must be continuously repeated. This requires the permanent engagement of molecular mechanisms that re-establish skeletal muscle integrity after each RE-induced muscle damage. Conclusion: Various molecular regulators coordinately control the adaptation of skeletal muscle after acute and repeated RE and expand their actions far beyond muscle growth. Variations of key resistance training variables likely affect these mechanisms without affecting muscle growth. Keywords: adaptation; hypertrophy; mTOR signaling; muscle damage; proteostasis; resistance exercise; skeletal muscle.
      5
  • Publication
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    Lactate Thresholds and the Simulation of Human Energy Metabolism: Contributions by the Cologne Sports Medicine Group in the 1970s and 1980s.
    (2022-07)
    Wackerhage, Henning 
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    Schulz, Henry 
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    Weber, Sebastian 
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    Ring-Dimitriou, Susanne 
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    Heine, Oliver 
    Today, researchers, practitioners, and physicians measure the concentration of lactate during a graded exercise test to determine thresholds related to the maximal lactate steady state (maxLass) as a sensitive measure of endurance capacity. In the 1970s and 1980s, a group of Cologne-based researchers around Wildor Hollmann, Alois Mader, and Hermann Heck developed the methodology for systematic lactate testing and introduced a 4 mmol.L−1 lactate threshold. Later, they also developed the concept of the maxLass, and Mader designed a sophisticated mathematical model of human energy metabolism during exercise. Mader`s model simulates metabolic responses to exercise based on individual variables such as maximum oxygen uptake (V˙ O2max) and the maximal rate of lactate formation (νLa.max). Mader’s model predicts that the νLa.max reduces the power at the anaerobic threshold and endurance performance but that a high νLa.max is required for events with high power outputs in elite athletes. Mader’s model also assumed before the millennium that the rate of fat oxidation is explained by the difference between glycolytic pyruvate synthesis and the actual rate of pyruvate oxidation which is consistent with current opinion. Mader’s model also simulated the V˙ O2max slow component in the mid-1980s. Unfortunately, several landmark studies by the Cologne group were only published in German, and as a result, contributions by the Cologne group are under-appreciated in the English-speaking world. This narrative review aims to introduce key contributions of the Cologne group to human metabolism research especially for readers who do not speak German.
      6
  • Publication
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    Repeated and Interrupted Resistance Exercise Induces the Desensitization and Re-Sensitization of mTOR-Related Signaling in Human Skeletal Muscle Fibers.
    (2022-05-12)
    Jacko, Daniel 
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    Schaaf, Kirill 
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    Masur, Lukas 
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    Windoffer, Hannes 
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    Aussieker, Thorben 
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    Schiffer, Thorsten 
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    Zacher, Jonas 
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    Bloch, Wilhelm 
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    The acute resistance exercise (RE)-induced phosphorylation of mTOR-related signaling proteins in skeletal muscle can be blunted after repeated RE. The time frame in which the phosphorylation (p) of mTORS2448, p70S6kT421/S424, and rpS6S235/236 will be reduced during an RE training period in humans and whether progressive (PR) loading can counteract such a decline has not been described. (1) To enclose the time frame in which pmTORS2448, prpS6S235/236, and pp70S6kT421/S424 are acutely reduced after RE occurs during repeated RE. (2) To test whether PR will prevent that reduction compared to constant loading (CO) and (3) whether 10 days without RE may re-increase blunted signaling. Fourteen healthy males (24 ± 2.8 yrs.; 1.83 ± 0.1 cm; 79.3 ± 8.5 kg) were subjected to RE with either PR (n = 8) or CO (n = 6) loading. Subjects performed RE thrice per week, conducting three sets with 10–12 repetitions on a leg press and leg extension machine. Muscle biopsies were collected at rest (T0), 45 min after the first (T1), seventh (T7), 13th (T13), and 14th (X-T14) RE session. No differences were found between PR and CO for any parameter. Thus, the groups were combined, and the results show the merged values. prpS6S235/236 and pp70s6kT421/S424 were increased at T1, but were already reduced at T7 and up to T13 compared to T1. Ten days without RE re-increased prpS6S235/236 and pp70S6kT421/S424 at X-T14 to a level comparable to that of T1. pmTORS2448 was increased from T1 to X-T14 and did not decline over the training period. Single-fiber immunohistochemistry revealed a reduction in prpS6S235/236 in type I fibers from T1 to T13 and a re-increase at X-T14, which was more augmented in type II fibers at T13 (p < 0.05). The entity of myofibers revealed a high heterogeneity in the level of prpS6S235/236, possibly reflecting individual contraction-induced stress during RE. The type I and II myofiber diameter increased from T0 and T1 to T13 and X-T14 (p < 0.05) prpS6S235/236 and pp70s6kT421/S424 reflect RE-induced states of desensitization and re-sensitization in dependency on frequent loading by RE, but also by its cessation.
      9
  • Publication
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    Effects of Acute and Chronic Resistance Exercise on the Skeletal Muscle Metabolome
    (2022-05) ;
    Patrick Weinisch 
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    Werner Römisch-Margl 
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    Richard Jaspers 
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    Anna Artati 
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    Jerzy Adamski 
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    Kenneth A. Dyar 
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    Thorben Aussieker 
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    Daniel Jacko 
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    Wilhelm Bloch 
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    Henning Wackerhage 
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    Gabi Kastenmüller 
    Resistance training promotes metabolic health and stimulates muscle hypertrophy, but the precise routes by which resistance exercise (RE) conveys these health benefits are largely unknown. Aim: To investigate how acute RE affects human skeletal muscle metabolism. Methods: We collected vastus lateralis biopsies from six healthy male untrained volunteers at rest, before the first of 13 RE training sessions, and 45 min after the first and last bouts of RE. Biopsies were analysed using untargeted mass spectrometry-based metabolomics. Results: We measured 617 metabolites covering a broad range of metabolic pathways. In the untrained state RE altered 33 metabolites, including increased 3-methylhistidine and N-lactoylvaline, suggesting increased protein breakdown, as well as metabolites linked to ATP (xanthosine) and NAD (N1-methyl-2-pyridone-5-carboxamide) metabolism; the bile acid chenodeoxycholate also increased in response to RE in muscle opposing previous findings in blood. Resistance training led to muscle hypertrophy, with slow type I and fast/intermediate type II muscle fibre diameter increasing by 10.7% and 10.4%, respectively. Comparison of post-exercise metabolite levels between trained and untrained state revealed alterations of 46 metabolites, including decreased N-acetylated ketogenic amino acids and increased beta-citrylglutamate which might support growth. Only five of the metabolites that changed after acute exercise in the untrained state were altered after chronic training, indicating that training induces multiple metabolic changes not directly related to the acute exercise response. Conclusion: The human skeletal muscle metabolome is sensitive towards acute RE in the trained and untrained states and reflects a broad range of adaptive processes in response to repeated stimulation.
      10
  • Publication
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    Is high-intensity interval training harmful to health?
    (2022)
    Joisten, Niklas 
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    Zimmer, Philipp 
    High-intensity interval training (HIIT) is a common method to increase performance and promote health in elite sports, rehabilitation, and disease prevention. Flockhart et al. suggest a limit of HIIT above which detrimental effects on metabolic health emerge. We put these findings into context and assess the evidence that HIIT might be harmful.
      1