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AIM: The present study aimed to investigate the effects of a single bout of resistance exercise on mitophagy in human skeletal muscle (SkM). METHODS: Eight healthy men were recruited to complete an acute bout of one-leg resistance exercise. SkM biopsies were obtained one hour after exercise in the resting leg (Rest-leg) and the contracting leg (Ex-leg). Mitophagy was assessed using protein-related abundance, transmission electron microscopy (TEM), and fluorescence microscopy. RESULTS: Our results show that acute resistance exercise increased pro-fission protein phosphorylation (DRP1Ser616) and decreased mitophagy markers such as PARKIN and BNIP3L/NIX protein abundance in the Ex-leg. Additionally, mitochondrial complex IV decreased in the Ex-leg when compared to the Rest-leg. In the Ex-leg, TEM and immunofluorescence images showed mitochondrial cristae abnormalities, a mitochondrial fission phenotype, and increased mitophagosome-like structures in both subsarcolemmal and intermyofibrillar mitochondria. We also observed increased mitophagosome-like structures on the subsarcolemmal cleft and mitochondria in the extracellular space of SkM in the Ex-leg. We stimulated human primary myotubes with CCCP, which mimics mitophagy induction in the Ex-leg, and found that BNIP3L/NIX protein abundance decreased independently of lysosomal degradation. Finally, in another human cohort, we found a negative association between BNIP3L/NIX protein abundance with both mitophagosome-like structures and mitochondrial cristae density in the SkM. CONCLUSION: The findings suggest that a single bout of resistance exercise can initiate mitophagy, potentially involving mitochondrial ejection, in human skeletal muscle. BNIP3L/NIX is proposed as a sensitive marker for assessing mitophagy flux in SkM.
Assuntos
Mitofagia , Músculo Esquelético , Humanos , Mitofagia/fisiologia , Masculino , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiologia , Adulto , Mitocôndrias Musculares/metabolismo , Mitocôndrias Musculares/ultraestrutura , Treinamento Resistido , Adulto Jovem , Proteínas de Membrana/metabolismoRESUMO
Desminopathy R350P is a human myopathy that is characterized by the progressive loss of muscle fiber organization. This results in the loss of muscle size, mobility, and strength. In desminopathy, inflammation affects muscle homeostasis and repair, and contributes to progressive muscle deterioration. Mitochondria morphology was also suggested to affect desminopathy progression. Epicatechin (Epi)-a natural compound found in cacao-has been proposed to regulate inflammatory signaling and mitochondria morphology in human and animal models. Hence, we hypothesize chronic Epi consumption to improve inflammatory pathway and mitochondria morphology in the peripheral blood mononuclear cells (PBMCs) of a desminopathy R350P patient. We found that 12 weeks of Epi consumption partially restored TRL4 signaling, indicative of inflammatory signaling and mitochondria morphology in the desminopathy patient. Moreover, Epi consumption improved blood health parameters, including reduced HOMA-IR and IL-6 levels in the desminopathy patient. This indicates that Epi consumption could be a useful tool to slow disease progression in desminopathy patients.
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Catequina , Leucócitos Mononucleares , Mitocôndrias , Humanos , Catequina/farmacologia , Catequina/administração & dosagem , Leucócitos Mononucleares/metabolismo , Leucócitos Mononucleares/efeitos dos fármacos , Mitocôndrias/metabolismo , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/patologia , Masculino , Distrofias Musculares/metabolismo , Distrofias Musculares/patologia , Distrofias Musculares/tratamento farmacológico , Distrofias Musculares/genética , Adulto , Feminino , Inflamação/metabolismo , Inflamação/patologia , Cardiomiopatias/metabolismo , Cardiomiopatias/patologia , Cardiomiopatias/tratamento farmacológico , Desmina/metabolismo , Desmina/genéticaRESUMO
Background: Reactive oxygen species (ROS) regulate glucose metabolism (GM) in skeletal muscle by improving the translocation of GLUT4. Antioxidant supplementation could block this physiological effect, altering glucose signaling during exercise. However, there is limited evidence in humans on whether antioxidant intake affects GM. Therefore, we aimed to determine the effect of an antioxidant cocktail (AOC) on GM at rest and during metabolic challenges. Methods: Ten healthy male subjects received AOC supplementation (1000 mg of Vitamin C, 600 IU of Vitamin E, and 600 mg of α-lipoic acid) or placebo (2.000 mg of talc) before two trials conducted 7 days apart. Trial 1: AOC 120 and 90 minutes before an endurance exercise (EEX) bout at 60 % of maximal oxygen uptake (VO2max); Trial 2: AOC 120 and 90 minutes before an oral glucose tolerance test (OGTT; 75 g glucose). Measurements of gas exchange and capillary blood samples were collected every 15 minutes during both trials. Results: AOC supplementation increased resting glucose levels (p<0.05). During Trial 1 (EEX), the AOC increased carbohydrate oxidation (CHOox) (p= 0.03), without effect in glucose blood levels. During Trial 2 (OGTT), the AOC supplementation had no significant effect on GM parameters. Conclusion: Acute supplementation with AOC increased resting glucose levels and CHOox during EEX in healthy subjects, with no effect on GM during the OGTT.
Antecedentes: Las especies reactivas de oxígeno (ROS) regulan el metabolismo de la glucosa (GM) en el músculo esquelético al mejorar la translocación de GLUT4. La suplementación con antioxidantes podría bloquear este efecto fisiológico, alterando la señalización de la glucosa durante el ejercicio. Sin embargo, existe evidencia limitada en humanos sobre si la ingesta de antioxidantes afecta el GM. Por lo tanto, nuestro objetivo fue determinar el efecto de un cóctel de antioxidantes (AOC) en el GM en reposo y durante desafíos metabólicos. Métodos: Sujetos sanos (sexo masculino; n= 10) recibieron suplementos de AOC (1.000 mg de vitamina C, 600 UI de vitamina E y 600 mg de ácido α-lipoico) o placebo (2.000 mg de talco) previo a dos pruebas realizadas con 7 días de diferencia. Prueba 1: AOC 120 y 90 minutos antes de una serie de ejercicio de resistencia (EEX) al 60% del consumo máximo de oxígeno (VO2max); prueba 2: AOC 120 y 90 minutos antes de una prueba de tolerancia oral a la glucosa (OGTT; 75 g de glucosa). Se obtuvieron datos de intercambio de gaseoso y muestras de sangre capilar cada 15 minutos durante ambas pruebas. Resultados: la suplementación con AOC aumentó los niveles de glucosa en reposo (p<0,05). Durante la prueba 1 (EEX), el AOC aumentó la oxidación de carbohidratos (CHOox) (p= 0,03), sin efecto en los niveles de glucosa en sangre. Durante la prueba 2 (OGTT), la suplementación con AOC no tuvo un efecto significativo en los parámetros de GM. Conclusión: Una suplementación aguda con AOC aumentó los niveles de glucosa en reposo y la CHOox durante EEX en sujetos sanos, sin efecto sobre el GM durante la OGTT.
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Kaposi's sarcoma is an angioproliferative neoplasm associated with the human herpesvirus 8. According to the clinical characteristics and the degree of immunosuppression, there are four epidemiological forms: classic, endemic, iatrogenic, and epidemic. The latter is associated with acquired immunodeficiency syndrome (AIDS) and 40% GI involvement. There is little epidemiological, clinical, and endoscopic evidence of the disease. This study sought to characterize this condition in a Colombian population and compare the findings with publications from other countries. One hundred thirty-five records of patients who consulted between 2011 and 2020 for Kaposi's sarcoma were reviewed, of which 24 had GI involvement. Epidemiological, clinical, endoscopic, and treatment characteristics were obtained. Twenty-two patients were men. There were 21 patients infected with human immunodeficiency virus (HIV; 87.5%) and 19 receiving antiretroviral therapy (90%); 33.3% had HIV viral load > 100,000 copies/mL. The CD4+ count was <50 cells/µL in 28.6% of cases, between 50 and 100 cells/µL in 19.0%, and between 100 and 200 cells/µL in 14.4%. The rate of infection by other opportunistic infections was 41.7%. There were GI symptoms in 33% of the patients, and the most frequent were hematochezia, abdominal pain, nausea, and diarrhea. Most had concomitant skin lesions (70.8%). GI lesions were located mainly in the oropharynx (41.7%), stomach (20.8%), and colon (16.7%). The most common endoscopic finding was maculopapular erythema. This article provided insight into the local epidemiology of gastrointestinal Kaposi's sarcoma. In contrast to studies in other populations, GI symptoms were more frequent in this one, and there was a difference in endoscopic findings. Studies with larger populations are needed.
El sarcoma de Kaposi es una neoplasia angioproliferativa asociada al virus del herpes humano 8. Según las características clínicas y el grado de inmunosupresión, son cuatro las formas epidemiológicas: clásica, endémica, iatrogénica y epidémica, esta última asociada al síndrome de inmunodeficiencia adquirida (SIDA) y con un 40% de compromiso gastrointestinal. Existe escasa evidencia epidemiológica, clínica y endoscópica de la enfermedad. Este estudio buscó caracterizar esta condición en una población colombiana y contrastar los hallazgos con publicaciones de otros países. Se revisaron 135 registros de pacientes que consultaron entre el 2011 y 2020 por sarcoma de Kaposi, de los cuales 24 tenían compromiso gastrointestinal. Se obtuvieron características epidemiológicas, clínicas, endoscópicas y tratamientos. Veintidós pacientes eran hombres. Hubo 21 pacientes infectados por virus de la inmunodeficiencia humana (VIH; 87,5%) y 19 recibían terapia antirretroviral (90%). El 33,3% tenía carga viral VIH > 100 000 copias/mL. El recuento de CD4+ fue < 50 cel/µL en el 28,6% de los casos, entre 50 y 100 cel/µL en el 19,0%, y entre 100 y 200 cel/µL en el 14,4%. La tasa de infecciones por otros oportunistas fue de 41,7%. Hubo síntomas gastrointestinales en el 33% de los pacientes y los más frecuentes fueron hematoquecia, dolor abdominal, náuseas y diarrea. La mayoría tuvo lesiones cutáneas concomitantes (70,8%). Las lesiones gastrointestinales se localizaron principalmente en la orofaringe (41,7%), estómago (20,8%) y colon (16,7%). El hallazgo endoscópico más común fue eritema maculopapular. Este artículo mostró una visión de la epidemiología local del sarcoma de Kaposi gastrointestinal. En contraste con estudios en otras poblaciones, en este, los síntomas gastrointestinales fueron más frecuentes y hubo diferencia en los hallazgos endoscópicos. Son necesarios estudios con poblaciones más grandes.
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In skeletal muscle (SkM), a reduced mitochondrial elongate phenotype is associated with several metabolic disorders like type 2 diabetes mellitus (T2DM). However, the mechanisms contributing to this reduction in mitochondrial elongate phenotype in SkM have not been fully elucidated. It has recently been shown in a SkM cell line that toll-like receptor 4 (TLR4) contributes to the regulation of mitochondrial morphology. However, this has not been investigated in human SkM. Here we found that in human SkM biopsies, TLR4 protein correlated negatively with Opa1 (pro-mitochondrial fusion protein). Moreover, the incubation of human myotubes with LPS reduced mitochondrial size and elongation and induced abnormal mitochondrial cristae, which was prevented with the co-incubation of LPS with TAK242. Finally, T2DM myotubes were found to have reduced mitochondrial elongation and mitochondrial cristae density. Mitochondrial morphology, membrane structure, and insulin-stimulated glucose uptake were restored to healthy levels in T2DM myotubes treated with TAK242. In conclusion, mitochondrial morphology and mitochondrial cristae seem to be regulated by the TLR4 pathway in human SkM. Those mitochondrial alterations might potentially contribute to insulin resistance in the SkM of patients with T2DM.
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BACKGROUND: Skeletal muscle is sensitive to bile acids (BA) because it expresses the TGR5 receptor for BA. Cholic (CA) and deoxycholic (DCA) acids induce a sarcopenia-like phenotype through TGR5-dependent mechanisms. Besides, a mouse model of cholestasis-induced sarcopenia was characterised by increased levels of serum BA and muscle weakness, alterations that are dependent on TGR5 expression. Mitochondrial alterations, such as decreased mitochondrial potential and oxygen consumption rate (OCR), increased mitochondrial reactive oxygen species (mtROS) and unbalanced biogenesis and mitophagy, have not been studied in BA-induced sarcopenia. METHODS: We evaluated the effects of DCA and CA on mitochondrial alterations in C2C12 myotubes and a mouse model of cholestasis-induced sarcopenia. We measured mitochondrial mass by TOM20 levels and mitochondrial DNA; ultrastructural alterations by transmission electronic microscopy; mitochondrial biogenesis by PGC-1α plasmid reporter activity and protein levels by western blot analysis; mitophagy by the co-localisation of the MitoTracker and LysoTracker fluorescent probes; mitochondrial potential by detecting the TMRE probe signal; protein levels of OXPHOS complexes and LC3B by western blot analysis; OCR by Seahorse measures; and mtROS by MitoSOX probe signals. RESULTS: DCA and CA caused a reduction in mitochondrial mass and decreased mitochondrial biogenesis. Interestingly, DCA and CA increased LC3II/LC3I ratio and decreased autophagic flux concordant with raised mitophagosome-like structures. In addition, DCA and CA decreased mitochondrial potential and reduced protein levels in OXPHOS complexes I and II. The results also demonstrated that DCA and CA decreased basal, ATP-linked, FCCP-induced maximal respiration and spare OCR. DCA and CA also reduced the number of cristae. In addition, DCA and CA increased the mtROS. In mice with cholestasis-induced sarcopenia, TOM20, OXPHOS complexes I, II and III, and OCR were diminished. Interestingly, the OCR and OXPHOS complexes were correlated with muscle strength and bile acid levels. CONCLUSION: Our results showed that DCA and CA decreased mitochondrial mass, possibly by reducing mitochondrial biogenesis, which affects mitochondrial function, thereby altering potential OCR and mtROS generation. Some mitochondrial alterations were also observed in a mouse model of cholestasis-induced sarcopenia characterised by increased levels of BA, such as DCA and CA.
Assuntos
Colestase , Sarcopenia , Animais , Camundongos , Sarcopenia/metabolismo , Sarcopenia/patologia , Fibras Musculares Esqueléticas/metabolismo , Músculo Esquelético/metabolismo , Mitocôndrias , Modelos Animais de Doenças , Colestase/metabolismo , Colestase/patologiaRESUMO
BACKGROUND: Skeletal muscle generates force and movements and maintains posture. Under pathological conditions, muscle fibers suffer an imbalance in protein synthesis/degradation. This event causes muscle mass loss and decreased strength and muscle function, a syndrome known as sarcopenia. Recently, our laboratory described secondary sarcopenia in a chronic cholestatic liver disease (CCLD) mouse model. Interestingly, the administration of ursodeoxycholic acid (UDCA), a hydrophilic bile acid, is an effective therapy for cholestatic hepatic alterations. However, the effect of UDCA on skeletal muscle mass and functionality has never been evaluated, nor the possible involved mechanisms. METHODS: We assessed the ability of UDCA to generate sarcopenia in C57BL6 mice and develop a sarcopenic-like phenotype in C2C12 myotubes and isolated muscle fibers. In mice, we measured muscle strength by a grip strength test, muscle mass by bioimpedance and mass for specific muscles, and physical function by a treadmill test. We also detected the fiber's diameter and content of sarcomeric proteins. In C2C12 myotubes and/or isolated muscle fibers, we determined the diameter and troponin I level to validate the cellular effect. Moreover, to evaluate possible mechanisms, we detected puromycin incorporation, p70S6K, and 4EBP1 to evaluate protein synthesis and ULK1, LC3 I, and II protein levels to determine autophagic flux. The mitophagosome-like structures were detected by transmission electron microscopy. RESULTS: UDCA induced sarcopenia in healthy mice, evidenced by decreased strength, muscle mass, and physical function, with a decline in the fiber's diameter and the troponin I protein levels. In the C2C12 myotubes, we observed that UDCA caused a reduction in the diameter and content of MHC, troponin I, puromycin incorporation, and phosphorylated forms of p70S6K and 4EBP1. Further, we detected increased levels of phosphorylated ULK1, the LC3II/LC3I ratio, and the number of mitophagosome-like structures. These data suggest that UDCA induces a sarcopenic-like phenotype with decreased protein synthesis and autophagic flux. CONCLUSIONS: Our results indicate that UDCA induces sarcopenia in mice and sarcopenic-like features in C2C12 myotubes and/or isolated muscle fibers concomitantly with decreased protein synthesis and alterations in autophagic flux.
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Sarcopenia , Camundongos , Animais , Sarcopenia/induzido quimicamente , Sarcopenia/patologia , Ácido Ursodesoxicólico/farmacologia , Ácido Ursodesoxicólico/metabolismo , Proteínas Quinases S6 Ribossômicas 70-kDa/metabolismo , Troponina I/metabolismo , Camundongos Endogâmicos C57BL , Músculo Esquelético/metabolismoRESUMO
The aim of this study was to compare the potential additional effect of chia flour, whey protein, and a placebo juice to resistance training on fat-free mass (FFM) and strength gains in untrained young men. Eighteen healthy, untrained young men underwent an 8-week whole-body resistance training program, comprising three sessions per week. Subjects were randomized into three groups that after each training session consumed: (1) 30 g whey protein concentrate containing 23 g protein (WG), (2) 50 g chia flour containing 20 g protein (CG), or (3) a placebo not containing protein (PG). Strength tests (lower- and upper-limb one repetition maximum (1 RM) tests) and body composition analyses (dual-energy X-ray absorptiometry; DXA) were performed before (PRE) and after (POST) the intervention. Resistance training increased FFM and the 1 RM for each of the strength tests similarly in the three groups. FFM increased by 2.3% in WG (p = 0.04), by 3.6% in CG (p = 0.004), and by 3.0% in PG (p = 0.002)., and 1 RM increased in the different strength tests in the three groups (p < 0.05) with no difference between PG, CG, and WG. In conclusion, neither chia flour nor whey protein supplementation elicited an enhanced effect on FFM and strength gains after an 8-week resistance training program in healthy, untrained young men consuming a habitual high protein mixed diet (>1.2 g/kg/day).
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Farinha , Treinamento Resistido , Masculino , Humanos , Proteínas do Soro do Leite , Suplementos Nutricionais , Método Duplo-Cego , Composição Corporal , Força Muscular , Músculo EsqueléticoRESUMO
SCOPE: Nonalcoholic fatty liver disease (NAFLD) has a high and growing prevalence globally. Mitochondria are fundamental in regulating cell energy homeostasis. Nevertheless, mitochondria control mechanisms can be exceeded in this context of energy overload. Damaged mitochondria worsen NAFLD progression. Diet and lifestyle changes are the main recommendations for NAFLD prevention and treatment. Some polyphenols have improved mitochondrial function in different NAFLD and obesity models. OBJECTIVE: The study aims to discuss the potential role of polyphenols as a nonpharmacological approach targeting mitochondria to prevent and treat NAFLD, analyzing the influence of polyphenols' chemical structure, limitations and clinical projections. METHODS: In vivo and in vitro NAFLD models were considered. Study searches were performed using the following keywords: nonalcoholic fatty liver disease, liver steatosis, mitochondria, mitochondrial activity, mitochondrial dynamics, mitochondrial dysfunction, mitochondrial morphology, mitochondrial cristae, fusion, fission, polyphenols, flavonoids, anthocyanins, AND/OR bioactive compounds. CONCLUSION: Polyphenols are a group of diverse bioactive molecules whose bioactive effects are highly determined by their chemical structure. These bioactive compounds could offer an interesting non-pharmacological approach to preventing and treating NAFLD, regulating mitochondrial dynamics and function. Nevertheless, the mitochondria' role in subjects with NAFLD treatment is not fully elucidated. The dosage and bioavailability of these compounds should be addressed when studied.
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Hepatopatia Gordurosa não Alcoólica , Humanos , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Hepatopatia Gordurosa não Alcoólica/metabolismo , Polifenóis/farmacologia , Polifenóis/uso terapêutico , Polifenóis/metabolismo , Antocianinas/farmacologia , Mitocôndrias , Dieta , Fígado/metabolismo , Mitocôndrias Hepáticas/metabolismoRESUMO
BACKGROUND: Skeletal muscle is sensitive to bile acids (BA) because it expresses the TGR5 receptor for BA. Cholic (CA) and deoxycholic (DCA) acids induce a sarcopenia-like phenotype through TGR5-dependent mechanisms. Besides, a mouse model of cholestasis-induced sarcopenia was characterised by increased levels of serum BA and muscle weakness, alterations that are dependent on TGR5 expression. Mitochondrial alterations, such as decreased mitochondrial potential and oxygen consumption rate (OCR), increased mitochondrial reactive oxygen species (mtROS) and unbalanced biogenesis and mitophagy, have not been studied in BA-induced sarcopenia.METHODS: We evaluated the effects of DCA and CA on mitochondrial alterations in C2C12 myotubes and a mouse model of cholestasis-induced sarcopenia. We measured mitochondrial mass by TOM20 levels and mitochondrial DNA; ultrastructural alterations by transmission electronic microscopy; mitochondrial biogenesis by PGC-1α plasmid reporter activity and protein levels by western blot analysis; mitophagy by the co-localisation of the MitoTracker and LysoTracker fluorescent probes; mitochondrial potential by detecting the TMRE probe signal; protein levels of OXPHOS complexes and LC3B by western blot analysis; OCR by Seahorse measures; and mtROS by MitoSOX probe signals. RESULTS: DCA and CA caused a reduction in mitochondrial mass and decreased mitochondrial biogenesis. Interestingly, DCA and CA increased LC3II/LC3I ratio and decreased autophagic flux concordant with raised mitophagosome-like structures. In addition, DCA and CA decreased mitochondrial potential and reduced protein levels in OXPHOS complexes I and II. The results also demonstrated that DCA and CA decreased basal, ATP-linked, FCCP-induced maximal respiration and spare OCR. DCA and CA also reduced the number of cristae. In addition, DCA and CA increased the mtROS. In mice with cholestasis-induced sarcopenia, TOM20, OXPHOS complexes I, II and III, and OCR were diminished. Interestingly, the OCR and OXPHOS complexes were correlated with muscle strength and bile acid levels. CONCLUSION: Our results showed that DCA and CA decreased mitochondrial mass, possibly by reducing mitochondrial biogenesis, which affects mitochondrial function, thereby altering potential OCR and mtROS generation. Some mitochondrial alterations were also observed in a mouse model of cholestasis-induced sarcopenia characterised by increased levels of BA, such as DCA and CA.