1. Teriparatide in sequental treatment of osteoporosis in a patient with spinal muscular atrophy : a case report and literature reviewMatej Rakuša, Lea Leonardis, Blaž Koritnik, Andrej Janež, Mojca Jensterle Sever, 2025, drugi znanstveni članki Povzetek: We report the case of a female patient with spinal muscular atrophy type 3c, low bone mineral density and multiple fragility fractures, successfully treated with teriparatide. She sustained a vertebral fracture at age 35 years while treatment naïve, and additionally, one vertebral fracture as well as an intertrochanteric right hip fracture during the 5-year treatment with oral bisphosphonates. A sequential 2-year treatment with teriparatide followed by a one-year treatment with oral bisphosphonate risedronate resulted in an overall 11-year fracture-free period and stable bone mineral density. Teriparatide is an osteoanabolic medication that effectively reduces vertebral and nonvertebral fractures in postmenopausal, male and glucocorticoid-induced osteoporosis, particularly in individuals at very high risk of fracture. In the context of neuromuscular disease, teriparatide proved effective in the treatment of osteoporosis in Duchenne muscular dystrophy. In contrast, the data for patients with spinal muscular atrophy are lacking. Further studies are needed to assess its role in this population.
Ključne besede: spinal muscular atrophy, osteoporosis, fracture
Objavljeno v DiRROS: 12.11.2025; Ogledov: 45; Prenosov: 14
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2. Alterations in Muscle Contractile Properties, Structure, and Function During 10-Day Bed Rest, Post-Recovery, and Following COVID-19 LockdownBoštjan Šimunič, Martino V. Franchi, Fabio Sarto, Elena Monti, zaključena znanstvena zbirka raziskovalnih podatkov Povzetek: We aimed to identify early tensiomyography alterations in six muscles during a 10-day bed rest (BR10), followed by a 30-day recovery period (R+30), and to compare these changes with those observed after the 54-day COVID-19 lockdown in ten healthy males (22.9 ± 5.0 years). Tensiomyography and muscle thickness (sonography) were assessed at baseline, during bed rest, at BR10, R+30, and after the COVID-19 lockdown. Additional assessments included vertical jump performance (force plate), body composition (bioimpedance), physical activity (GPAQ), and lower back pain (VAS). By BR10, participants experienced a 1.9% body mass loss, a 3.8% increase in fat mass, and a 2.4% reduction in muscle mass. While anthropometric parameters returned to baseline by R+30, fat mass increased again by 3.9% post-lockdown. Jump height declined by 10.1% at BR10, returned to baseline at R+30, and remained stable thereafter. Muscle thickness decreased by 7.0% in the vastus lateralis at BR10 and by 10.1% post-lockdown. Tensiomyographic amplitude increased in all five leg muscles prior to BR10, recovered at R+30 and increased again after the COVID-19 lockdown, while a reduction was observed in the erector spinae within the first 48 hours, coinciding with reported lower back pain. In the erector spinae, both delay and contraction time decreased during BR10 and post-lockdown. In contrast, contraction time of the biceps femoris increased before BR10 and remained elevated post-lockdown. Overall, tensiomyographic parameters after the COVID-19 lockdown changed in the same direction as during bed rest, though to a lesser degree, make it a sensitive tool for detecting changes in muscle structural and functional quality after bed rest and reduced activity paradigms.
Ključne besede: Atrophy, Bed rest, Physical inactivity, Skeletal muscle, Tensiomyography
Objavljeno v DiRROS: 25.06.2025; Ogledov: 401; Prenosov: 0
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3. Neuromotor changes in postural control following bed restRamona Ritzmann, Christoph Centner, Luke Hughes, Janice Waldvogel, Uroš Marušič, 2025, pregledni znanstveni članek Povzetek: Chronic bed rest (BR) serves as a model for studying the effects of prolongedimmobility on physiological and neuromotor functions, particularly postural control. ProlongedBR leads to significant deconditioning of postural balance control, characterized by increasedsway path lengths, sway velocity and fall risk, independent of muscle strength. These changes arelinked to neural adaptations at spinal and supraspinal levels, including structural and functionalbrain changes, such as alterations in grey and white matter, increased cerebellar activation,reduced spinal excitability and increased latencies within reflex circuitries. Additionally, BRdisrupts sensory integration from proprioceptive, visual and vestibular systems, impairing post-ural stability. Visual reliance remains stable during BR, though decreased visual acuity andcontrast sensitivity are noted. Moreover, BR-induced shifts in cerebrospinal fluid contribute toaltered brain activity, impacting sensorimotor function. Vestibular system adaptations, includingchanges in vestibulospinal reflexes, further exacerbate balance impairments. Understanding thesemechanisms is crucial for developing interventions to mitigate the adverse effects of BR onpostural control and prevent prolonged recovery times or increased risk of injury. This reviewhighlights the need for further research into the neural underpinnings of BR-induced posturalinstability, with a focus on sensory integration and neuroplasticity
Ključne besede: atrophy, balance, disuse, immobilization, muscle
Objavljeno v DiRROS: 18.04.2025; Ogledov: 541; Prenosov: 327
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4. Spaceflight on the ISS changed the skeletal muscle proteome of two astronautsMarta Murgia, Joern Rittweger, Carlo Reggiani, Roberto Bottinelli, Matthias Mann, Stefano Schiaffino, Marco Vincenzo Narici, 2024, izvirni znanstveni članek Povzetek: Skeletal muscle undergoes atrophy and loss of force during long space missions, when astronauts are persistently exposed to altered gravity and increased ionizing radiation. We previously carried out mass spectrometry-based proteomics from skeletal muscle biopsies of two astronauts, taken before and after a mission on the International Space Station. The experiments were part of an effort to find similarities between spaceflight and bed rest, a ground-based model of unloading, focused on proteins located at the costameres. We here extend the data analysis of the astronaut dataset and show compartment-resolved changes in the mitochondrial proteome, remodeling of the extracellular matrix and of the antioxidant response. The astronauts differed in their level of onboard physical exercise, which correlated with their respective preservation of muscle mass and force at landing in previous analyses. We show that the mitochondrial proteome downregulation during spaceflight, particularly the inner membrane and matrix, was dramatic for both astronauts. The expression of autophagy regulators and reactive oxygen species scavengers, however, showed partially opposite expression trends in the two subjects, possibly correlating with their level of onboard exercise. As mitochondria are primarily affected in many different tissues during spaceflight, we hypothesize that reactive oxygen species (ROS) rather than mechanical unloading per se could be the primary cause of skeletal muscle mitochondrial damage in space. Onboard physical exercise might have a strong direct effect on the prevention of muscle atrophy through mechanotransduction and a subsidiary effect on mitochondrial quality control, possibly through upregulation of autophagy and anti-oxidant responses.
Ključne besede: skeletal muscles, microgravity, muscle atrophy, autophagy
Objavljeno v DiRROS: 12.11.2024; Ogledov: 726; Prenosov: 608
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5. Premalignant gastric lesions in patients included in National colorectal cancer screeningBojan Tepeš, Maja Šeruga, Miroslav Vujasinović, Dejan Urlep, Liljana Ljepovic, Nataša Brglez Jurecic, Alenka Forte, Anita Kek-Ljubec, Miha Skvarč, 2018, izvirni znanstveni članek Povzetek: Background. Gastric cancer is the fifth most common malignancy in the world with almost one million new cases annually. Helicobacter pylori infection causes 89% of all gastric cancers. Premalignant lesions (atrophy and intestinal metaplasia) develop after several decades of inflammation. Secondary prevention with gastroscopy is possible, but it is costly and has a low compliance rate. Alternative procedures like serology testing for pepsinogen I and II and pepsinogen I/II ratio are available to select patients for surveillance gastroscopies. Patients and methods. In seven outpatient endoscopic units, 288 patients (154 men; 53.5%), average age 60.68 years, tested positive in National colorectal cancer screening programme SVIT, were included in the study. Gastropanel (BioHit, Finland) was used as a serologic biopsy method. Results. We found 24 patients (12 men, mean age 63.7 years) with pepsinogen (pepsinogen I/II < 3 and/or pepsinogen I < 30 %g/L). Premalignant changes were found on gastric biopsies in 21 patients (7.3% incidence). Operative Link on Gastric Intestinal Metaplasia Assessment (OLGIM) % 1 was found in 20 patients; Operative Link for Gastritis Assessment (OLGA) % 1 was found in 19 patients. Combined accuracy for preneoplastic lesions in Gastropanel positive patients was 87.5%. H. pylori seropositivity was found in 219 patients (76%). Only 24% of our population had normal results. Conclusions. Gastropanel test has proven to be a reliable non-invasive test for advanced gastric preneoplastic lesions that can select patients for further gastroscopy. We found high H. pylori seropositivity in older age groups in Slovenia.
Ključne besede: Helicobacter pylori, gastropanel, atrophy, Slovenia, intestinal metaplasia, gastric cancer, SVIT
Objavljeno v DiRROS: 02.07.2024; Ogledov: 947; Prenosov: 290
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6. Pathophysiological mechanisms of reduced physical activity : insights from the human step reduction model and animal analoguesFabio Sarto, Roberto Bottinelli, Martino V. Franchi, Simone Porcelli, Boštjan Šimunič, Rado Pišot, Marco Vincenzo Narici, 2023, pregledni znanstveni članek Povzetek: Physical inactivity represents a heavy burden for modern societies and is spreading worldwide, it is a recognised pandemic and is the fourth cause of global mortality. Not surprisingly, there is an increasing interest in longitudinal studies on the impact of reduced physical activity on different physiological systems. This narrative review focuses on the pathophysiological mechanisms of step reduction (SR), an experimental paradigm that involves a sudden decrease in participants’ habitual daily steps to a lower level, mimicking the effects of a sedentary lifestyle. Analogous animal models of reduced physical activity, namely the “wheel-lock” and the “cage reduction” models, which can provide the foundation for human studies, are also discussed. The empirical evidence obtained thus far shows that even brief periods of reduced physical activity can lead to substantial alterations in skeletal muscle health and metabolic function. In particular, decrements in lean/muscle mass, muscle function, muscle protein synthesis, cardiorespiratory fitness, endothelial function and insulin sensitivity, together with an increased fat mass and inflammation, have been observed. Exercise interventions seem particularly effective for counteracting these pathophysiological alterations induced by periods of reduced physical activity. A direct comparison of SR with other human models of unloading, such as bed rest and lower limb suspension/immobilisation, is presented. In addition, we propose a conceptual framework aiming to unravel the mechanisms of muscle atrophy and insulin resistance in the specific context of reduced ambulatory activity. Finally, methodological considerations, knowledge gaps and future directions for both animal and human models are also discussed in the review.
Ključne besede: physical inactivity, cage reduction, insulin sensitivity, muscle atrophy
Objavljeno v DiRROS: 29.06.2023; Ogledov: 1392; Prenosov: 893
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7. Neuromuscular junction instability and altered intracellular calcium handling as early determinants of force loss during unloading in humansElena Monti, Carlo Reggiani, Martino V. Franchi, Luana Toniolo, Marco Sandri, Andrea Armani, Sandra Zampieri, Boštjan Šimunič, Rado Pišot, Marco Vincenzo Narici, 2021, izvirni znanstveni članek Povzetek: Unloading induces rapid skeletal muscle atrophy and functional decline. Importantly, force is lost at a much higher rate than muscle mass. We aimed to investigate the early determinants of the disproportionate loss of force compared to that of muscle mass in response to unloading. Ten young participants underwent 10 days of bed rest (BR). At baseline (BR0) and at 10 days (BR10), quadriceps femoris (QF) volume (VOL) and isometric maximum voluntary contraction (MVC) were assessed. At BR0 and BR10 blood samples and biopsies of vastus lateralis (VL) muscle were collected. Neuromuscular junction (NMJ) stability and myofibre innervation status were assessed, together with single fibre mechanical properties and sarcoplasmic reticulum (SR) calcium handling. From BR0 to BR10, QFVOL and MVC decreased by 5.2% (P = 0.003) and 14.3% (P < 0.001), respectively. Initial and partial denervation was detected from increased neural cell adhesion molecule (NCAM)-positive myofibres at BR10 compared with BR0 (+3.4%, P = 0.016). NMJ instability was further inferred from increased C-terminal agrin fragment concentration in serum (+19.2% at BR10, P = 0.031). Fast fibre cross-sectional area (CSA) showed a trend to decrease by 15% (P = 0.055) at BR10, while single fibre maximal tension (force/CSA) was unchanged. However, at BR10 SR Ca2+ release in response to caffeine decreased by 35.1% (P < 0.002) and 30.2% (P < 0.001) in fast and slow fibres, respectively, pointing to an impaired excitation%contraction coupling. These findings support the view that the early onset of NMJ instability and impairment in SR function are eligible mechanisms contributing to the greater decline in muscle force than in muscle size during unloading.
Ključne besede: Ca2+ dynamics, muscle atrophy, neuromuscular junction instability, sarcoplasmic reticulum, single fibre atrophy, single fibre contractile impairment, unloading
Objavljeno v DiRROS: 16.06.2021; Ogledov: 2286; Prenosov: 2032
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