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The production of a cellularized silk fibroin scaffold is very difficult because it is actually impossible to differentiate cells into a well-organized cardiac tissue. Without vascularization, not only do cell masses fail to grow, but they may also exhibit an area of necrosis, indicating a lack of oxygen and nutrients. In the present study, we used the so-called tyrosine protein kinase kit (c-Kit)-positive cardiac progenitor cells (CPCs) to generate cardiac cellularized silk fibroin scaffolds, multipotent cells isolated from the adult heart to date that can show some degree of differentiation toward the cardiac phenotype. To test their ability to differentiate into the cardiac phenotype in vivo as well, CPC and collagen organoid-like masses were implanted into nude mice and their behavior observed. Since the 3-dimensional structure of cardiac tissue can be preserved by scaffolds, we prepared in parallel different silk fibroin scaffolds with 3 different geometries and tested their behavior in 3 different models of immunosuppressed animals. Unfortunately, CPC cellularized silk fibroin scaffolds cannot be used in vivo. CPCs implanted alone or in collagen type I gel were destroyed by CD3+ lymphocyte aggregates, whereas the porous and partially oriented scaffolds elicited a consistent foreign body response characterized by giant cells. Only the electrospun meshes were resistant to the foreign body reaction. In conclusion, c-Kit-positive CPCs, although expressing a good level of cardiac differentiation markers in vitro with or without fibroin meshes, are not suitable for an in vivo model of cardiac organoids because they are degraded by a T-cell-mediated immune response. Even scaffolds which may preserve the survival of these cells in vivo also induced a host response. However, among the tested scaffolds, the electrospun meshes (F-scaffold) induced a lower response compared to all the other tested structures.
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Fibroínas , Camundongos , Animais , Fibroínas/química , Seda/química , Alicerces Teciduais/química , Engenharia Tecidual/métodos , Camundongos Nus , Células-Tronco/metabolismoRESUMO
To date, there are limited and incomplete data on possible sex-based differences in fiber-types of skeletal muscle and their response to physical exercise. Adult healthy male and female mice completed a single bout of endurance exercise to examine the sex-based differences of the peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC1α), heat shock protein 60 (Hsp60), interleukin 6 (IL-6) expression, as well as the Myosin Heavy Chain (MHC) fiber-type distribution in soleus and extensor digitorum longus (EDL) muscles. Our results showed for the first time that in male soleus, a muscle rich of type IIa fibers, endurance exercise activates specifically genes involved in mitochondrial biogenesis such as PGC1 α1 isoform, Hsp60 and IL-6, whereas the expression of PGC1 α2 and α3 was significantly upregulated in EDL muscle, a fast-twitch skeletal muscle, independently from the gender. Moreover, we found that the acute response of different PGC1α isoforms was muscle and gender dependent. These findings add a new piece to the huge puzzle of muscle response to physical exercise. Given the importance of these genes in the physiological response of the muscle to exercise, we strongly believe that our data could support future research studies to personalize a specific and sex-based exercise training protocol.
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Atividade Motora , Músculo Esquelético/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Animais , Chaperonina 60/genética , Chaperonina 60/metabolismo , Feminino , Interleucina-6/genética , Interleucina-6/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Músculo Esquelético/fisiologia , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Fatores SexuaisRESUMO
Conjugated linoleic acid (CLA) has been reported to improve muscle hypertrophy, steroidogenesis, physical activity, and endurance capacity in mice, although the molecular mechanisms of its actions are not completely understood. The aim of the present study was to identify whether CLA alters the expression of any of the peroxisome proliferator-activated receptor γ coactivator 1α (PGC1α) isoforms, and to evaluate the possible existence of fibre-type-specific hypertrophy in the gastrocnemius and plantaris muscles. Mice were randomly assigned to one of four groups: placebo sedentary, CLA sedentary, placebo trained, or CLA trained. The CLA groups were gavaged with 35 µl per day of Tonalin® FFA 80 food supplement containing CLA throughout the 6-week experimental period, whereas the placebo groups were gavaged with 35 µl sunflower oil each day. Each administered dose of CLA corresponded to approximately 0.7 g/kg or 0.5%, of the dietary daily intake. Trained groups ran 5 days per week on a Rota-Rod for 6 weeks at increasing speeds and durations. Mice were sacrificed by cervical dislocation and hind limb posterior muscle groups were dissected and used for histological and molecular analyses. Endurance training stimulated mitochondrial biogenesis by PGC1α isoforms (tot, α1, α2, and α3) but CLA supplementation did not stimulate PGC1α isoforms or mitochondrial biogenesis in trained or sedentary mice. In the plantaris muscle, CLA supplementation induced a fibre-type-specific hypertrophy of type IIx muscle fibres, which was associated with increased capillary density and was different from the fibre-type-specific hypertrophy induced by endurance exercise (of types I and IIb muscle fibres). J. Cell. Physiol. 232: 1086-1094, 2017. © 2016 Wiley Periodicals, Inc.
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Ácidos Linoleicos Conjugados/farmacologia , Fibras Musculares Esqueléticas/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Condicionamento Físico Animal , Adenilato Quinase/metabolismo , Animais , Suplementos Nutricionais , Membro Posterior/efeitos dos fármacos , Lectinas/metabolismo , Masculino , Camundongos Endogâmicos BALB C , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Fibras Musculares Esqueléticas/efeitos dos fármacos , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismoRESUMO
Probiotics have shown the potential to counteract the loss of muscle mass, reduce physical fatigue, and mitigate inflammatory response following intense exercise, although the mechanisms by which they work are not very clear. The objective of this review is to describe the main harmful effects of alcohol on skeletal muscle and to provide important strategies based on the use of probiotics. The excessive consumption of alcohol is a worldwide problem and has been shown to be crucial in the progression of alcoholic liver disease (ALD), for which, to date, the only therapy available is lifestyle modification, including cessation of drinking. In ALD, alcohol contributes significantly to the loss of skeletal muscle, and also to changes in the intestinal microbiota, which are the basis for a series of problems related to the onset of sarcopenia. Some of the main effects of alcohol on the skeletal muscle are described in this review, with particular emphasis on the "gut-liver-muscle axis", which seems to be the primary cause of a series of muscle dysfunctions related to the onset of ALD. The modulation of the intestinal microbiota through probiotics utilization has appeared to be crucial in mitigating the muscle damage induced by the high amounts of alcohol consumed.
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The emergence of tele-exercise as a response to the impact of technology on physical activity has opened up new possibilities for promoting physical health. By integrating innovative technologies and open-source platforms, tele-exercise encourages people to stay active. In our latest analysis, we delved into the scientific literature surrounding the use of tele-exercise technologies in training healthy individuals. After conducting an extensive search on the PubMed database using the keywords "tele-exercise" and "physical activity" (from 2020 to 2023), we identified 44 clinical trials that were applicable to tele-exercise, but less than 10% of them were aimed at healthy individuals, precisely 9.09% (four out of forty-four studies analyzed). Our review highlights the potential of tele-exercise to help maintain physical fitness and psychological well-being, especially when traditional fitness facilities are not an option. We also underscore the importance of interoperability, standardization, and the incorporation of biomechanics, exercise physiology, and neuroscience into the development of tele-exercise platforms. Nevertheless, despite these promising benefits, research has shown that there is still a significant gap in the knowledge concerning the definition and evaluation of training parameters for healthy individuals. As a result, we call for further research to establish evidence-based practices for tele-exercise in the healthy population.
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INTRODUCTION: We investigated changes in satellite cell (SC) pool size after an acute bout of strenuous exercise and evaluated the influence of baseline SC count and fiber type. METHODS: Participants completed a downhill running (DHR) intervention (5 × 8 min, 2-min rest; 80% VO2max ; -10% gradient). Muscle biopsies were taken 7 days before VO2max and 7-9 days after the DHR intervention. Delayed-onset muscle soreness (DOMS) and creatine kinase activity (CK) were measured on days 1, 2, 7, and 9 post-DHR. SCs were identified by Pax7 and laminin staining. Relative distribution of MHC isoforms was determined by electrophoresis. RESULTS: DOMS and CK peaked on day 1 post-DHR (P < 0.01). The SC pool increased (26%) after DHR (P = 0.005). SCs/total myonuclei after recovery correlated with baseline SCs (r = 0.979, P = 0.003) and VO2max (r = 0.956, P = 0.011), whereas change in SC pool (Pax7(+) cells/total myonuclei: recovery minus baseline) tended to correlate with percent MHC II (r = 0.848; P = 0.06). CONCLUSION: Interindividual physiological characteristics affect SC pool expansion after a single bout of DHR and are influenced by VO2max .
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Diferenciação Celular/fisiologia , Exercício Físico/fisiologia , Músculo Esquelético/citologia , Corrida/fisiologia , Células Satélites de Músculo Esquelético/fisiologia , Adulto , Contagem de Células/métodos , Humanos , Masculino , Músculo Esquelético/patologia , Músculo Esquelético/fisiologia , Adulto JovemRESUMO
Open-water swimming is a rapidly growing sport discipline worldwide, and clinical problems associated with long-distance swimming are now better recognized and managed more effectively. The most prevalent medical risk associated with an open-water swimming event is hypothermia; therefore, the Federation Internationale De Natation (FINA) has instituted 2 rules to reduce this occurrence related to the minimum water temperature and the time taken to complete the race. Another medical risk that is relevant to open-water swimmers is heat stroke, a condition that can easily go unnoticed. The purpose of this review is to shed light on this physiological phenomenon by examining the physiological response of swimmers during long-distance events, to define a maximum water temperature limit for competitions. We conclude that competing in water temperatures exceeding 33°C should be avoided.
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Golpe de Calor/epidemiologia , Esforço Físico , Natação , Golpe de Calor/etiologia , Humanos , Medição de Risco , Fatores de Risco , Temperatura , Água/químicaRESUMO
This descriptive article explores the use of smart devices for health and wellness in the context of telehealth, highlighting rapidly evolving technologies such as the Internet of Things (IoT) and Artificial Intelligence (AI). Key innovations, benefits, challenges, and opportunities related to the adoption of these technologies are outlined. The article provides a descriptive and accessible approach to understanding the evolution and impact of smart devices in the tele-exercise reality. Nowadays, technological advances provide solutions that were unthinkable just a few years ago. The habits of the general population have also changed over the past few years. Hence, there is a need to investigate this issue and draw the attention of the scientific community to this topic by describing the benefits and challenges associated with each topic. If individuals no longer go to exercise, the exercise must go to their homes instead.
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Probiotics are live microorganisms that yield health benefits when consumed, generally by improving or restoring the intestinal flora (microbiota) as part of the muco-microbiotic layer of the bowel. In this work, mice were fed with ethanol alone or in combination with the probiotic Lactobacillus fermentum (L. fermentum) for 12 weeks. The modulation of the NF-κB signaling pathway with the induction of Hsp60, Hsp90, and IkB-α by the probiotic occurred in the jejunum. L. fermentum inhibited IL-6 expression and downregulated TNF-α transcription. NF-κB inactivation concurred with the restoration of the intestinal barrier, which had been damaged by ethanol, via the production of tight junction proteins, ameliorating the ethanol-induced intestinal permeability. The beneficial effect of the probiotic on the intestine was repeated for the cerebellum, in which downregulation of glial inflammation-related markers was observed in the probiotic-fed mice. The data show that L. fermentum exerted anti-inflammatory and cytoprotective effects in both the small intestine and the cerebellum, by suppressing ethanol-induced increased intestinal permeability and curbing neuroinflammation. The results also suggest that L. fermentum could be advantageous, along with the other available means, for treating intestinal diseases caused by stressors associated with inflammation and dysbiosis.
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The purposes of the present study were to investigate the effect of conjugated linoleic acid (CLA) supplementation on testosterone levels in vitro on a cell line derived from Leydig cells (R2C) and in vivo in the blood of physically active subjects before and after a resistance exercise bout. In vitro R2C cells were treated with different CLA concentrations (0-30 µM) for 24 and 48 hours. After treatment, supernatant media were tested to determine testosterone secretion. The CLA increased the testosterone secretion only after 48 hours. In vivo, 10 resistance-trained male subjects, in a double-blind placebo-controlled and crossover study design were randomized for 3 weeks of either 6 g·d⻹ CLA or placebo. Blood was drawn pre and post each resistance exercise bout to determine the total testosterone and sex hormone-binding globulin (SHBG) levels. No significant differences were observed for total testosterone or SHBG pre and post each resistance exercise bout; although after the resistance exercise bouts, total testosterone increased moderately (effect size = moderate), whereas after CLA supplementation, there was a large increase in total testosterone (effect size = large). CLA supplementation induced an increase in testosterone levels in Leydig cells in vitro after 48 hours but not in vivo before and after a resistance exercise bout. These findings suggest that CLA supplementation may promote testosterone synthesis through a molecular pathway that should be investigated in the future, although this effect did not have an anabolic relevance in our in vivo model.
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Exercício Físico/fisiologia , Células Intersticiais do Testículo/efeitos dos fármacos , Ácido Linoleico/farmacologia , Treinamento Resistido , Globulina de Ligação a Hormônio Sexual/metabolismo , Testosterona/sangue , Adulto , Animais , Linhagem Celular , Estudos Cross-Over , Suplementos Nutricionais , Método Duplo-Cego , Humanos , Células Intersticiais do Testículo/metabolismo , Masculino , Ratos , Testosterona/biossínteseRESUMO
An investigation into the histological changes in skeletal muscle fibres and jump performance indicators after 8 weeks of plyometric squat jump training was conducted. Healthy inactive participants (n = 13; age: 21.5 ± 1.7 year.; height: 173.6 ± 10.7 cm; weight: 68.5 ± 18.4 kg; BMI 22.4 ± 3.8 kg/m2) were recruited, where eight participants completed plyometric squat jump training and five control participants refrained from performing any jumping activities. Blood samples, vastus lateralis muscle biopsies and functional testing (peak and average power, peak and average velocity, maximal jump height) were collected/recorded 10 days prior to and 3 days after the training/rest period. Participants completed 1644 squat jumps over an 8-week training period of 24 sessions with a progressive increase in the number of squat jumps. The trained group significantly increased their jumping average and peak power (mean increases in average power: 16.7 ± 1.2% and peak power: 8.2% ± 0.1) and velocity (mean increases in average velocity: 13.7 ± 0.1% and peak velocity: 5.2% ± 0.03), resulting in a 25% improvement in vertical jump height. No muscle morphological changes in terms of the cross-sectional area (CSA) or muscle-fibre-type transition were observed after the plyometric training. Improvements in the functional performance indicators following training may more likely be explained by sarcomere ultrastructural adaptation, which did not directly affect myosin heavy chain or CSA.
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Currently, no commercially available drugs have the ability to reverse cachexia or counteract muscle wasting and the loss of lean mass. Here, we report the methodology used to develop Physiactisome-a conditioned medium released by heat shock protein 60 (Hsp60)-overexpressing C2C12 cell lines enriched with small and large extracellular vesicles. We also present evidence supporting its use in the treatment of cachexia. Briefly, we obtain a nanovesicle-based secretion by genetically modifying C2C12 cell lines with an Hsp60-overexpressing plasmid. The secretion is used to treat naïve C2C12 cell lines. Physiactisome activates the expression of PGC-1α isoform 1, which is directly involved in mitochondrial biogenesis and muscle atrophy suppression, in naïve C2C12 cell lines. Proteomic analyses show Hsp60 localisation inside isolated nanovesicles and the localisation of several apocrine and merocrine molecules, with potential benefits for severe forms of muscle atrophy. Considering that Physiactisome can be easily obtained following tissue biopsy and can be applied to autologous muscle stem cells, we propose a potential nanovesicle-based anti-cachexia drug that could mimic the beneficial effects of exercise. Thus, Physiactisome may improve patient survival and quality of life. Furthermore, the method used to add Hsp60 into nanovesicles can be used to deliver other drugs or active proteins to vesicles.
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Caquexia , Chaperonina 60 , Caquexia/metabolismo , Chaperonina 60/metabolismo , Humanos , Músculo Esquelético/metabolismo , Atrofia Muscular/patologia , Proteômica , Qualidade de VidaRESUMO
Recognition of diseases associated with mutations of the chaperone system genes, e.g., chaperonopathies, is on the rise. Hereditary and clinical aspects are established, but the impact of the mutation on the chaperone molecule and the mechanisms underpinning the tissue abnormalities are not. Here, histological features of skeletal muscle from a patient with a severe, early onset, distal motor neuropathy, carrying a mutation on the CCT5 subunit (MUT) were examined in comparison with normal muscle (CTR). The MUT muscle was considerably modified; atrophy of fibers and disruption of the tissue architecture were prominent, with many fibers in apoptosis. CCT5 was diversely present in the sarcolemma, cytoplasm, and nuclei in MUT and in CTR and was also in the extracellular space; it colocalized with CCT1. In MUT, the signal of myosin appeared slightly increased, and actin slightly decreased as compared with CTR. Desmin was considerably delocalized in MUT, appearing with abnormal patterns and in precipitates. Alpha-B-crystallin and Hsp90 occurred at lower signals in MUT than in CTR muscle, appearing also in precipitates with desmin. The abnormal features in MUT may be the consequence of inactivity, malnutrition, denervation, and failure of protein homeostasis. The latter could be at least in part caused by malfunction of the CCT complex with the mutant CCT5 subunit. This is suggested by the results of the in silico analyses of the mutant CCT5 molecule, which revealed various abnormalities when compared with the wild-type counterpart, mostly affecting the apical domain and potentially impairing chaperoning functions. Thus, analysis of mutated CCT5 in vitro and in vivo is anticipated to provide additional insights on subunit involvement in neuromuscular disorders.
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This study was aimed at evaluating the prevalence of use of dietary supplements (DSs) among gym users and gym instructors involved in body shaping-oriented fitness training. Furthermore, this study aimed to verify whether differences existed in the prevalence and in the types of DSs used in both gym users and gym instructors involved in body shaping-oriented fitness competitions vs. those not involved in fitness competitions. A survey was distributed to 316 participants, composed of 89 gym instructors and 227 gym users of both genders aged 27.3 ± 7.7. Among these participants, 52 were involved in competitions and 248 were not, while 16 participants did not specify either way. The results showed a high prevalence in the use of DSs in the population considered, with 85.4% of the participants declaring they used DSs, with high heterogeneity in the numbers and in the combinations used. No differences were found between gym instructors and gym users, or between participants involved and those not involved in competitions. The results indicate that DSs are widely used by persons involved in body shaping-oriented fitness training. The results also suggest that the majority of the participants decided individually which DSs to use.
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Suplementos Nutricionais , Exercício Físico , Adulto , Estudos Transversais , Feminino , Humanos , Masculino , Prevalência , Inquéritos e Questionários , Adulto JovemRESUMO
In the last few years, there has been emerging interest in developing treatments against human diseases using natural bioactive content. Here, the powder of the edible mushroom Pleurotus eryngii var. eryngii was mixed with the normal diet of mice bearing C26 colon carcinoma. Interestingly, it was evidenced by a significant increase in the survival rate of C26 tumor-bearing mice accompanied by a significant increase in Hsp90 and Hsp27 protein levels in the tumors. These data were paralleled by a decrease in Hsp60 levels. The mushroom introduced in the diet induced the inhibition of the transcription of the pro-inflammatory cytokines IL-6 and IL-1 exerting an anti-inflammatory action. The effects of the mushroom were mediated by the activation of c-Jun NH2-terminal kinases as a result of metabolic stress induced by the micronutrients introduced in the diet. In the tumors of C26 bearing mice fed with Pleurotus eryngii there was also a decreased expression of the mitotic regulator survivin and the anti-apoptotic factor Bcl-xL as well as an increase in the expression levels of Atg7, a protein that drives autophagy. In our hypothesis the interplay of these molecules favored the survival of the mice fed with the mushroom. These data are promising for the introduction of Pleurotus eryngii as a dietary supplement or as an adjuvant in anti-cancer therapy.
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Neoplasias do Colo/dietoterapia , Pleurotus , Animais , Suplementos Nutricionais , Modelos Animais de Doenças , Feminino , Resposta ao Choque Térmico/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , FitoterapiaRESUMO
The αB-crystallin (HSPB5) protein is modulated in response to a wide variety of stressors generated by multiple physio-pathological conditions, sustained by reactive oxygen species (ROS) production. In cardiac muscle tissue, this protein regulates various cellular processes, such as protein degradation, apoptosis and the stabilization of cytoskeletal elements. In this work, we studied the role of HSPB5 expression, activation and localization in HL-1 murine cardiomyocytes exposed to pro-oxidant and non-cytotoxic H2O2 concentration, as well as in cardiac tissue isolated from mice following an acute, non-damaging endurance exercise. Our results demonstrated that HSPB5 is the most abundant HSP in both cardiac muscle tissue and HL-1 cells when compared to HSPB1 or HSPA1A (≈3-8 fold higher protein concentrations, p < 0.01). The acute exposure of cardiac muscle cells to sustainable level of H2O2 "in vitro" or to aerobic non-damaging exercise "in vivo" determined a fast and specific increase of HSPB5 phosphorylation (from 3 up to 25 fold increase, p < 0.01) correlated to an increase in lipid peroxidation (p < 0.05). In both experimental models, p-HSPB5 likely facilitated both the interaction with ß-actin, desmin, and α-Filamin 1, the last one identified as new HSPB5 substrate in cardiac cells, as well as the sub-localization of HSPB5 within the same cellular compartment or the re-localization between compartments (i.e., nucleus and cytosol). Taken together, these data point out the role of "oxidative eustress" induced by physiological conditions in activating the molecular machinery devoted to cardiomyocytes' protection and candidate HSPB5 as a putative molecular mediator for the health benefits induced in cardiac tissue by exercise training.
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Peróxido de Hidrogênio , Cadeia B de alfa-Cristalina , Animais , Camundongos , Oxirredução , Fosforilação , Proteólise , Espécies Reativas de Oxigênio , Cadeia B de alfa-Cristalina/genética , Cadeia B de alfa-Cristalina/metabolismoRESUMO
In the last few years, a major goal of cardiac research has been to drive stem cell differentiation to replace damaged myocardium. Several research groups have attempted to differentiate potential cardiac stem cells (CSCs) using bi- or three-dimensional systems supplemented with growth factors or molecules acting as differentiating substances. We hypothesize that these systems failed to induce a complete differentiation because they lacked an architectural space. In the present study, we isolated a pool of small proliferating and fibroblast-like cells from adult rat myocardium. The phenotype of these cells was assessed and the characterized cells were cultured in a collagen I/OPLA scaffold with horse serum to obtain fine myocardial differentiation. C-Kit(POS)/Sca-1(POS) CSCs fully differentiated in vitro when an environment more similar to the CSC niche was created. These experiments demonstrated an important model for the study of the biology of CSCs and the biochemical pathways that lead to myocardial differentiation. The results pave the way for a new surgical approach.
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Células-Tronco Adultas/citologia , Diferenciação Celular/efeitos dos fármacos , Colágeno Tipo I/farmacologia , Miócitos Cardíacos/citologia , Soro , Alicerces Teciduais , Actinas/metabolismo , Células-Tronco Adultas/metabolismo , Animais , Separação Celular/métodos , Células Clonais/citologia , Células Clonais/metabolismo , Conexina 43/metabolismo , Feminino , Fator de Transcrição GATA4/metabolismo , Proteínas de Homeodomínio/metabolismo , Cavalos , Proteínas de Filamentos Intermediários/metabolismo , Proteínas com Homeodomínio LIM , Microscopia Eletrônica de Transmissão , Desenvolvimento Muscular/efeitos dos fármacos , Miocárdio/citologia , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/ultraestrutura , Cadeias Pesadas de Miosina/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Nestina , Proteínas Proto-Oncogênicas c-kit/metabolismo , Ratos , Ratos Sprague-Dawley , Fatores de Transcrição , Troponina T/metabolismoRESUMO
The purpose of this study was to investigate if exertional rhabdomyolysis induced by an acute bout of plyometric exercise in untrained individuals was associated with histological characteristics of skeletal muscle, creatine kinase (CK) polymorphism or secondary damage. Twenty-six healthy male untrained individuals completed a bout of plyometric exercise (10 sets of 10 maximal squat jumps, with each standardized to achieve at least 95% of individual maximal jump height). Blood samples were taken, and perceived pain was scored immediately before the exercise intervention and 6 h, 1, 2, and 3 days post-intervention. Muscle biopsies were collected 9 or 4 days before (baseline) and 3 days after plyometric jumps. Subjects were divided into two groups, high (n = 10) and low responders (n = 16), based on a cut-off limit for exertional rhabdomyolysis of peak CK activity ≥ 1000 U/L in any post-exercise blood sample. Perceived pain was more severe assessed in squat than standing position. Low responders perceived more pain at 6 h and 1 day, while high responders perceived more pain than low responders on days three and four after exercise; structural (dystrophin staining) and ultra-structural (transmission electron microscopy) analysis of muscle fibers revealed no baseline pathology; damage was evident in all individuals in both groups, with no difference between high and low responders in either damage or fiber type proportion. High responders had significantly higher total white blood cell and neutrophil counts 6 h and significantly higher C-reactive protein (CRP) 6 h and days one and two after exercise compared to low responders. High responders had significantly greater muscle myeloperoxidase (MPO) levels in baseline and 3 day post-exercise biopsies compared to baseline of low responders. MLCK C49T single polymorphism was present in 26% of volunteers, whose CK responses were not higher than those with MLCK CC or CT genotype. In conclusion, perceived pain is more effectively assessed with potentially affected muscle under eccentric strain, even if static. High CK responders also have pronounced CRP responses to unaccustomed plyometric exercise intervention. Exertional rhabdomyolysis after unaccustomed eccentric exercise may be related to underlying inability to resolve intramuscular MPO.
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Increased physical activity is an optimal way to maintain a good health. During exercise, triacylglycerols, an energy reservoir in adipose tissue, are hydrolyzed to free fatty acids (FAs) which are then released to the circulation, providing a fuel for working muscles. Thus, regular physical activity leads to a reduction of adipose tissue mass and improves metabolism. However, the reduction of lipid reservoir is also associated with many other interesting changes in adipose tissue FA metabolism. For example, a prolonged exercise contributes to a decrease in lipoprotein lipase activity and resultant reduction of FA uptake. This results in the improvement of mitochondrial function and upregulation of enzymes involved in the metabolism of polyunsaturated fatty acids. The exercise-induced changes in adipocyte metabolism are associated with modifications of FA composition. The modifications are adipose tissue depot-specific and follow different patterns in visceral and subcutaneous adipose tissue. Moreover, exercise affects adipokine release from adipose tissue, and thus, may mitigate inflammation and improve insulin sensitivity. Another consequence of exercise is the recently described phenomenon of adipose tissue "beiging," i.e., a switch from energy-storing white adipocyte phenotype to thermogenic FA oxidizing beige adipocytes. This process is regulated by myokines released during the exercise. In this review, we summarize published evidence for the exercise-related changes in FA metabolism and adipokine release in adipose tissue, and their potential contribution to beneficial cardiovascular and metabolic effects of physical activity.