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Sarcopenia describes an age-related decline in skeletal muscle mass, strength, and function that ultimately impairs metabolism and leads to poor balance, frequent falling, limited mobility, and a reduction in quality of life. Here we investigate the pathogenesis of sarcopenia through a proteomic shotgun approach. In brief, we employed tandem mass tags to quantitate and compare the protein profiles obtained from young versus old rat slow-twitch type of muscle (soleus) and a fast-twitch type of muscle (extensor digitorum longus, EDL). Our results disclose 3452 and 1848 proteins identified from soleus and EDL muscles samples, of which 78 and 174 were found to be differentially expressed, respectively. In general, most of the proteins were structural related and involved in energy metabolism, oxidative stress, detoxification, or transport. Aging affected soleus and EDL muscles differently, and several proteins were regulated in opposite ways. For example, pyruvate kinase had its expression and activity different in both soleus and EDL muscles. We were able to verify with existing literature many of our differentially expressed proteins as candidate aging biomarkers and, most importantly, disclose several new candidate biomarkers such as the glioblastoma amplified sequence, zero ß-globin, and prolargin.
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Envejecimiento/metabolismo , Proteínas Musculares/metabolismo , Músculo Esquelético/metabolismo , Proteoma/metabolismo , Animales , Transporte Biológico , Creatina Quinasa/metabolismo , Metabolismo Energético , Masculino , Peso Molecular , Músculo Esquelético/fisiología , Tamaño de los Órganos , Estrés Oxidativo , Proteolisis , Proteómica , Piruvato Quinasa/metabolismo , Ratas , Ratas Wistar , Coloración y Etiquetado , Espectrometría de Masas en TándemRESUMEN
Branched-chain amino acids (BCAA) (especially leucine) have been shown to activate protein synthesis pathways, decrease proteolysis and increase insulin sensitivity. Furthermore, it appears that leucine can be used as a nutritional therapy to avoid sarcopenia and skeletal muscle atrophy due to immobilization or glucocorticoid treatment. However, it is of note that all of these conditions are related to insulin resistance to varying degrees and affect different tissues, particularly skeletal muscle. Additionally, evidence from recent studies demonstrate that a combination of protein containing high levels of leucine with nutrients containing saturated fatty acids or an excess of leucine are capable of inducing insulin resistance. From this discussion, a few major questions arise. First, what is the role of a combination of macronutrients in inducing insulin resistance? Second, in insulin resistance, does leucine supplementation follow the same path observed under healthy conditions? Finally, what are the dose-dependent outcome and the latency of leucine effect under such conditions? The present article discusses these questions based on data from the literature and experiments performed by our group.
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Glucosa/metabolismo , Homeostasis , Leucina/metabolismo , Dexametasona/administración & dosificación , Proteínas en la Dieta/administración & dosificación , Humanos , Resistencia a la Insulina , Modelos TeóricosRESUMEN
INTRODUÇÃO: Recentes evidências indicam que a suplementação de creatina (Cr) é capaz de aumentar a densidade mineral óssea (DMO) no fêmur de ratos saudáveis em crescimento. Entretanto, há poucos estudos que testam a efetividade da suplementação desse nutriente em condições de perda óssea. OBJETIVO: Investigar o efeito da suplementação de Cr na DMO e no conteúdo mineral ósseo (CMO) de ratos espontaneamente hipertensos (SHR), um modelo experimental de baixa massa óssea. MATERIAIS E MÉTODOS: Dezesseis ratos SHR machos com 8 meses de idade foram randomizados em dois grupos experimentais pareados pelo peso corporal, a saber: 1) Pl: SHR tratados com placebo (água destilada; n = 8); e 2) Cr: SHR tratados com Cr (n = 8). Após nove semanas de suplementação os animais foram eutanasiados e o fêmur e a coluna vertebral (L1-L4) foram analisados por densitometria óssea (Dual Energy X-Ray Absorptiometry). RESULTADOS: Não houve diferença significativa na DMO (Pl = 0,249 ± 0,003 g/cm² vs. Cr = 0,249 ± 0,004 g/cm²; P = 0,95) e no CMO (Pl = 0,509 ± 0,150 g vs. Cr = 0,509 ± 0,017 g; P = 0,99) da coluna vertebral e na DMO (Pl = 0,210 ± 0,004 g/cm² vs. Cr = 0,206 ± 0,004 g/cm2;P = 0,49) e no CMO (Pl = 0,407 ± 0,021 g vs. Cr = 0,385 ± 0,021 g; P = 0,46) do fêmur total entre os grupos experimentais. CONCLUSÃO: Neste estudo, usando um modelo experimental de baixa massa óssea, a suplementação de Cr não afetou a massa óssea.
INTRODUCTION: Recent evidence has suggested that creatine supplementation (Cr) can increase the bone mineral density (BMD) of the femur in healthy growing rats. Nevertheless, studies assessing the efficacy of the Cr supplementation in conditions characterized by bone mass loss are scarce. OBJECTIVE: To investigate the effect of Cr supplementation on BMD and bone mineral content (BMC) in spontaneously hypertensive rats (SHRs), an experimental model of osteoporosis. MATERIALS AND METHODS: Sixteen 8-month-old male SHRs were randomly allocated into two groups matched by body weight: 1) Pl group: SHRs treated with placebo (distilled water; n = 8); and 2) Cr group: SHRs treated with Cr (n = 8). After nine weeks of supplementation, the animals were euthanized and their femur and spine (L1-L4) were analyzed by use of densitometry (Dual Energy X-Ray Absorptiometry). RESULTS: No significant difference was observed between the groups regarding either the spine or the total femur measures as follows: spine - BMD (Pl = 0.249 ± 0.003 g/cm² vs. Cr = 0.249 ± 0.004 g/cm²; P = 0.95) and BMC (Pl = 0.509 ± 0.150 g vs. Cr = 0.509 ± 0.017 g; P > 0.99); and total femur - BMD (Pl = 0.210 ± 0.004 g/cm² vs. Cr = 0.206 ± 0.004 g/cm²; P > 0.49) and BMC (Pl = 0.407 ± 0.021 g vs. Cr = 0.385 ± 0.021 g; P > 0.46). CONCLUSION: In this study, using the experimental model of osteoporosis, Cr supplementation had no effect on bone mass.
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Animales , Masculino , Ratas , Densidad Ósea/efectos de los fármacos , Creatina/farmacología , Ratas Endogámicas SHRRESUMEN
INTRODUCTION: Recent evidence has suggested that creatine supplementation (Cr) can increase the bone mineral density (BMD) of the femur in healthy growing rats. Nevertheless, studies assessing the efficacy of the Cr supplementation in conditions characterized by bone mass loss are scarce. OBJECTIVE: To investigate the effect of Cr supplementation on BMD and bone mineral content (BMC) in spontaneously hypertensive rats (SHRs), an experimental model of osteoporosis. MATERIALS AND METHODS: Sixteen 8-month-old male SHRs were randomly allocated into two groups matched by body weight: 1) Pl group: SHRs treated with placebo (distilled water; n = 8); and 2) Cr group: SHRs treated with Cr (n = 8). After nine weeks of supplementation, the animals were euthanized and their femur and spine (L1-L4) were analyzed by use of densitometry (Dual Energy X-Ray Absorptiometry). RESULTS: No significant difference was observed between the groups regarding either the spine or the total femur measures as follows: spine - BMD (Pl = 0.249 ± 0.003 g/cm² vs. Cr = 0.249 ± 0.004 g/cm²; P = 0.95) and BMC (Pl = 0.509 ± 0.150 g vs. Cr = 0.509 ± 0.017 g; P > 0.99); and total femur - BMD (Pl = 0.210 ± 0.004 g/cm² vs. Cr = 0.206 ± 0.004 g/cm²; P > 0.49) and BMC (Pl = 0.407 ± 0.021 g vs. Cr = 0.385 ± 0.021 g; P > 0.46). CONCLUSION: In this study, using the experimental model of osteoporosis, Cr supplementation had no effect on bone mass.
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Densidad Ósea/efectos de los fármacos , Creatina/farmacología , Animales , Masculino , Ratas , Ratas Endogámicas SHRRESUMEN
Physical inactivity leads to the accumulation of visceral fat and, consequently, to the activation of a network of inflammatory pathways which may promote development of insulin resistance, atherosclerosis, neurodegeneration, and tumour growth. These conditions belong to the "diseasome of physical inactivity". In contrast, the protective effect of regular exercise against diseases associated with chronic inflammation may to some extent be ascribed to an anti-inflammatory effect. The so called "acute exercise threshold", the complex mixture of several variables involved in exercise, such as type, volume, frequency, and intensity range is capable of inducing positive physiological adaptations and has been specifically addressed in the recent literature. The major concern is related to the level of the threshold: "exercise training shifts from a therapeutic adaptive intervention to one with potential pathological consequences". Nonetheless, if the mechanical stimulus is too weak to disrupt cellular homeostasis, training adaptations will not occur. Answering these questions could present practical applications, especially during inflammatory diseases associated with detrimental muscle effects and could theoretically constitute a "new" therapeutic approach to treat/improve an inflammatory state. This paper aims to describe specific data from the literature regarding the effects of exercise on inflammatory diseases in order to promote a more sophisticated perspective on the anti-inflammatory effects of exercise.
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Terapia por Ejercicio/métodos , Ejercicio Físico , Contracción Muscular/inmunología , Músculo Esquelético/fisiopatología , Miositis/inmunología , Miositis/prevención & control , Humanos , Modelos InmunológicosRESUMEN
BACKGROUND: Exacerbated oxidative stress is thought to be a mediator of arterial hypertension. It has been postulated that creatine (Cr) could act as an antioxidant agent preventing increased oxidative stress. The aim of this study was to investigate the effects of nine weeks of Cr or placebo supplementation on oxidative stress and cardiovascular parameters in spontaneously hypertensive rats (SHR). FINDINGS: Lipid hydroperoxidation, one important oxidative stress marker, remained unchanged in the coronary artery (Cr: 12.6 ± 1.5 vs. Pl: 12.2 ± 1.7 nmol·mg-1; p = 0.87), heart (Cr: 11.5 ± 1.8 vs. Pl: 14.6 ± 1.1 nmol·mg-1; p = 0.15), plasma (Cr: 67.7 ± 9.1 vs. Pl: 56.0 ± 3.2 nmol·mg-1; p = 0.19), plantaris (Cr: 10.0 ± 0.8 vs. Pl: 9.0 ± 0.8 nmol·mg-1; p = 0.40), and EDL muscle (Cr: 14.9 ± 1.4 vs. Pl: 17.2 ± 1.5 nmol·mg-1; p = 0.30). Additionally, Cr supplementation affected neither arterial blood pressure nor heart structure in SHR (p > 0.05). CONCLUSIONS: Using a well-known experimental model of systemic arterial hypertension, this study did not confirm the possible therapeutic effects of Cr supplementation on oxidative stress and cardiovascular dysfunction associated with arterial hypertension.
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Skeletal muscle protein turnover is modulated by intracellular signaling pathways involved in protein synthesis, degradation, and inflammation. The proinflammatory status of muscle cells, observed in pathological conditions such as cancer, aging, and sepsis, can directly modulate protein translation initiation and muscle proteolysis, contributing to negative protein turnover. In this context, branched-chain amino acids (BCAAs), especially leucine, have been described as a strong nutritional stimulus able to enhance protein translation initiation and attenuate proteolysis. Furthermore, under inflammatory conditions, BCAA can be transaminated to glutamate in order to increase glutamine synthesis, which is a substrate highly consumed by inflammatory cells such as macrophages. The present paper describes the role of inflammation on muscle remodeling and the possible metabolic and cellular effects of BCAA supplementation in the modulation of inflammatory status of skeletal muscle and the consequences on protein synthesis and degradation.
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This study aimed to develop an equipment and system of resistance exercise (RE), based on squat-type exercise for rodents, with control of training variables. We developed an operant conditioning system composed of sound, light and feeding devices that allowed optimized RE performance by the animal. With this system, it is not necessary to impose fasting or electric shock for the animal to perform the task proposed (muscle contraction). Furthermore, it is possible to perform muscle function tests in vivo within the context of the exercise proposed and control variables such as intensity, volume (sets and repetitions), and exercise session length, rest interval between sets and repetitions, and concentric strength. Based on the experiments conducted, we demonstrated that the model proposed is able to perform more specific control of other RE variables, especially rest interval between sets and repetitions, and encourages the animal to exercise through short-term energy restriction and "disturbing" stimulus that do not promote alterations in body weight. Therefore, despite experimental limitations, we believe that this RE apparatus is closer to the physiological context observed in humans.
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Prueba de Esfuerzo/instrumentación , Modelos Animales , Entrenamiento de Fuerza/instrumentación , Entrenamiento de Fuerza/métodos , Animales , Conducta Animal , Peso Corporal , Diseño de Equipo , Masculino , Ratas , Ratas WistarRESUMEN
The impact of leucine supplementation and resistance exercise (RE) on plasma lipid profile was evaluated in adult rats treated with dexamethasone, an experimental model of dyslipidemia. Total cholesterol did not differ among groups. Furthermore, leucine supplementation did not promote improvement in the plasma total cholesterol and LDL-c of the animals. However, plasma TG and VLDL-c were significantly decreased and HDL-c increased after 7 days of leucine supplementation combined with RE. In conclusion, leucine supplementation combined with RE, but not isolated, improved the plasma lipid profile of dexamethasone-induced dyslipidemic rats.
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Suplementos Dietéticos , Hipolipemiantes/uso terapéutico , Leucina/uso terapéutico , Lípidos/sangre , Entrenamiento de Fuerza , Animales , Dexametasona , Dislipidemias/inducido químicamente , Dislipidemias/tratamiento farmacológico , Hipolipemiantes/farmacología , Leucina/farmacología , Masculino , Ratas , Ratas WistarRESUMEN
Dexamethasone (DEXA) is a potent immunosupressant and anti-inflammatory agent whose main side effects are muscle atrophy and insulin resistance in skeletal muscles. In this context, leucine supplementation may represent a way to limit the DEXA side effects. In this study, we have investigated the effects of a low and a high dose of leucine supplementation (via a bolus) on glucose homeostasis, muscle mass and muscle strength in energy-restricted and DEXA-treated rats. Since the leucine response may also be linked to the administration of this amino acid, we performed a second set of experiments with leucine given in bolus (via gavage) versus leucine given via drinking water. Leucine supplementation was found to produce positive effects (e.g., reduced insulin levels) only when administrated in low dosage, both via the bolus or via drinking water. However, under DEXA treatment, leucine administration was found to significantly influence this response, since leucine supplementation via drinking water clearly induced a diabetic state, whereas the same effect was not observed when supplied via the gavage.
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Glucemia/metabolismo , Dexametasona/efectos adversos , Glucocorticoides/efectos adversos , Resistencia a la Insulina , Insulina/sangre , Leucina/administración & dosificación , Músculo Esquelético/efectos de los fármacos , Animales , Suplementos Dietéticos , Relación Dosis-Respuesta a Droga , Vías de Administración de Medicamentos , Homeostasis/efectos de los fármacos , Leucina/farmacología , Leucina/uso terapéutico , Masculino , Fuerza Muscular/efectos de los fármacos , Músculo Esquelético/metabolismo , Músculo Esquelético/patología , Atrofia Muscular/inducido químicamente , Atrofia Muscular/tratamiento farmacológico , Ratas , Ratas WistarRESUMEN
We aimed to investigate the possible role of creatine (CR) supplementation in counteracting dexamethasone-induced muscle wasting and insulin resistance in rats. Also, we examined whether CR intake would modulate molecular pathways involved in muscle remodeling and insulin signaling. Animals were randomly divided into four groups: (1) dexamethasone (DEX); (2) control pair-fed (CON-PF); (3) dexamethasone plus CR (DEX-CR); and (4) CR pair-fed (CR-PF). Dexamethasone (5 mg/kg/day) and CR (5 g/kg/day) were given via drinking water for 7 days. Plantaris and extensor digitorum longus (EDL) muscles were removed for analysis. Plantaris and EDL muscle mass were significantly reduced in the DEX-CR and DEX groups when compared with the CON-PF and CR-PF groups (P<0.05). Dexamethasone significantly decreased phospho-Ser473-Akt protein levels compared to the CON-PF group (P<0.05) and CR supplementation aggravated this response (P<0.001). Serum glucose was significantly increased in the DEX group when compared with the CON-PF group (DEX 7.8±0.6 vs. CON-PF 5.2±0.5 mmol/l; P<0.05). CR supplementation significantly exacerbated hyperglycemia in the dexamethasone-treated animals (DEX-CR 15.1±2.4 mmol/l; P<0.05 vs. others). Dexamethasone reduced GLUT-4 translocation when compared with the CON-PF and CR-PF (P<0.05) groups and this response was aggravated by CR supplementation (P<0.05 vs. others). In conclusion, supplementation with CR resulted in increased insulin resistance and did not attenuate muscle wasting in rats treated with dexamethasone. Given the contrast with the results of human studies that have shown benefits of CR supplementation on muscle atrophy and insulin sensitivity, we suggest caution when extrapolating this animal data to human subjects.
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Creatina/administración & dosificación , Dexametasona/administración & dosificación , Resistencia a la Insulina , Músculo Esquelético/efectos de los fármacos , Atrofia Muscular/metabolismo , Animales , Glucemia/efectos de los fármacos , Agua Potable , Transportador de Glucosa de Tipo 4/metabolismo , Humanos , Masculino , Músculo Esquelético/metabolismo , Atrofia Muscular/tratamiento farmacológico , Proteínas Proto-Oncogénicas c-akt/metabolismo , RatasRESUMEN
OBJECTIVE: We aimed to evaluate the effects of resistance exercise (RE) and leucine (LEU) supplementation on dexamethasone (DEXA)-induced muscle atrophy and insulin resistance. METHODS: Male Wistar rats were randomly divided into DEXA (DEX), DEXA + RE (DEX-RE), DEXA + LEU (DEX-LEU), and DEXA + RE + LEU (DEX-RE-LEU) groups. Each group received DEXA 5 mg · kg(-1) · d(-1) for 7 d from drinking water and were pair-fed to the DEX group; LEU-supplemented groups received 0.135 g · kg(-1) · d(-1) through gavage for 7 d; the RE protocol was based on three sessions of squat-type exercise composed by three sets of 10 repetitions at 70% of maximal voluntary strength capacity. RESULTS: The plantaris mass was significantly greater in both trained groups compared with the non-trained groups. Muscle cross-sectional area and fiber areas did not differ between groups. Both trained groups displayed significant increases in the number of intermediated fibers (IIa/IIx), a decreased number of fast-twitch fibers (IIb), an increased ratio of the proteins phospho(Ser2448)/total mammalian target of rapamycin and phospho(Thr389)/total 70-kDa ribosomal protein S6 kinase, and a decreased ratio of phospho(Ser253)/total Forkhead box protein-3a. Plasma glucose was significantly increased in the DEX-LEU group compared with the DEX group and RE significantly decreased hyperglycemia. The DEX-LEU group displayed decreased glucose transporter-4 translocation compared with the DEX group and RE restored this response. LEU supplementation worsened insulin sensitivity and did not attenuate muscle wasting in rats treated with DEXA. Conversely, RE modulated glucose homeostasis and fiber type transition in the plantaris muscle. CONCLUSION: Resistance exercise but not LEU supplementation promoted fiber type transition and improved glucose homeostasis in DEXA-treated rats.
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Glucemia/metabolismo , Resistencia a la Insulina/fisiología , Leucina/farmacología , Músculo Esquelético , Atrofia Muscular/prevención & control , Condicionamiento Físico Animal/fisiología , Entrenamiento de Fuerza , Animales , Dexametasona , Suplementos Dietéticos , Transportador de Glucosa de Tipo 4/metabolismo , Hiperglucemia/metabolismo , Hiperglucemia/prevención & control , Masculino , Movimiento/fisiología , Fuerza Muscular/efectos de los fármacos , Fuerza Muscular/fisiología , Músculo Esquelético/anatomía & histología , Músculo Esquelético/citología , Músculo Esquelético/fisiología , Atrofia Muscular/inducido químicamente , Atrofia Muscular/metabolismo , Distribución Aleatoria , Ratas , Ratas Wistar , Proteínas Quinasas S6 Ribosómicas 70-kDa/metabolismoRESUMEN
Branched-chain amino acids (BCAA) supplementation has been considered an interesting nutritional strategy to improve skeletal muscle protein turnover in several conditions. In this context, there is evidence that resistance exercise (RE)-derived biochemical markers of muscle soreness (creatine kinase (CK), aldolase, myoglobin), soreness, and functional strength may be modulated by BCAA supplementation in order to favor of muscle adaptation. However, few studies have investigated such effects in well-controlled conditions in humans. Therefore, the aim of this short report is to describe the potential therapeutic effects of BCAA supplementation on RE-based muscle damage in humans. The main point is that BCAA supplementation may decrease some biochemical markers related with muscle soreness but this does not necessarily reflect on muscle functionality.
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The aim of the present study was to evaluate, in adults, the nutritional statusand risk factors for cardiovascular disease and correlate them with exercise. We evaluated 77 employees , both male and female, aged an average 31.5 years. Body weight, height, waist circumference (WC), hip circumference (HC) and body fat percent (BF%) were measured. Cardiovascular risk was assessed by waist-to-hip ratio (WHR) and conicity index (CI). Weanalyzed blood pressure, total cholesterol, triglycerides and glucose. Alcohol consumption and physical exercise were also evaluated. According to BMI, 77.8% were eutrophic, 20.8% overweight and 1.3% underweight in the total sample. As for BF%, 44.2% were above the average and 41.6% below it. The variables serum cholesterol and exercise showed significant correlation (p = 0.001), and all individuals who had borderline cholesterol levels did not exercise regularly. Through the comparison of numerical variables between physical activity and triglyceride values, higher values of serum triglycerides were found for those who did not do physical exercise (p = 0.037). The remaining variables showed no significant differences. Only 1.3% of men had metabolic syndrome and this classification was not relatedto physical exercise. Although this is a population with a high prevalence of sedentarism, elevated triglycerides and overweight, it can be inferred that the study population showed a low prevalence of cardiovascular disease risk.
El objetivo de este estudio fue evaluar, en adultos, el estado nutricional y factores de riesgo de enfermedad cardiovascular y larelación con la práctica de ejercicio físico. Se estudiaron 77 empleados de ambos sexos,con un promedio de 31,5 años. Se midieron: peso, talla, circunferencia de cintura (CC), circunferencia de cadera (HC) y porcentaje de grasa corporal (% GC). El riesgo cardiovascular fue estimado por medio de la relación cinturacadera (RCC) y el índice de conicidad (IC). Sedeterminaron: presión arterial, colesterol total, triglicéridos y glucosa, consumo de alcoholy ejercicio físico. De acuerdo con el IMC del grupo de estudio, 77,8% eran eutróficos; 20,8%presentaban sobrepeso y 1,3% estaban con bajopeso. Con respecto a G%, 44,2% estaban sobrela media y 41,6% bajo la media. El riesgo para enfermedades cardiovasculares por el IC fue de13%. El colesterol sérico mostró una correlación positiva significativa (p=0,001) con la prácticade actividad física y todas las personas que portaban índice de colesterol elevado o limítrofe no practicaban ejercicio con regularidad. La comparación de variables numéricas entre actividad física y niveles de triglicéridos mostraba estos últimos más elevados en los individuos que no practicaban ejercicio físico (p = 0,037). Las otras variables estudiadas nomostraron diferencias significativas. Solamente el 1,3% de los hombres presentaba SM que no se relacionaba con la práctica de ejercicio físico. Apesar de ser una población con alta prevalencia de sedentarismo, portadora de triglicéridos elevados y sobrepeso, presenta baja prevalenciade ECV.
O objetivo do presente estudo foi avaliar, em adultos, o estado nutricional e fatores de risco para doenças cardiovasculares e correlacioná-los com a prática de exercício físico. Foram avaliados 77 funcionários, de ambos os gêneros, com média de 31,5 anos. Foram mensurados: peso, estatura, circunferência da cintura (CC), do quadril (CQ) e percentual de gordura (%G). O risco cardiovascular foi avaliado pela relação cintura-quadril (RCQ) e pelo índice de conicidade (IC). Analisou-se pressão arterial, colesterol total, triglicérides e glicemia; consumo de bebida alcoólica e prática de exercícios físicos. De acordo com o IMC, observou-se eutrofia em 77,8%, 20,8% com sobrepeso e 1,3% baixo peso na amostra total. Quanto ao %G, 44,2% encontravam-se acima da média e 41,6% abaixo da média. O risco para doenças cardiovasculares pelo IC foi de 13%. As variáveis colesterol total sérico e prática de exercícios apresentaram correlação positiva significante (p=0,001), sendo que todos os indivíduos que apresentaram taxa de colesterol limítrofe não praticavam exercícios físicos de modo regular. Por meio da comparação das variáveis numéricas entre prática de exercício físico e triglicérides foram encontrados valores maiores de triglicérides séricos nos que não praticavam exercício físico (p=0,037). As demais variáveis não apresentaram diferenças significativas. Apenas 1,3% dos indivíduos do gênero masculino apresentaram SM e esta classificação não apresentou relação com a prática de exercício físico. Apesar de se tratar de uma população com altas prevalências de sedentarismo, triglicérides elevados, sobrepeso, pode-se inferir que a população de estudo apresentou baixa prevalência de risco para DCV.
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Humanos , Masculino , Femenino , Adulto , Persona de Mediana Edad , Enfermedades Cardiovasculares/prevención & control , Técnicas de Ejercicio con Movimientos/estadística & datos numéricos , Composición Corporal , Estado Nutricional , Factores de Riesgo , Interpretación Estadística de DatosRESUMEN
The characterization of the mechanisms underlying skeletal muscle atrophy under different conditions has been a constant focus of research. Among anti-atrophic therapies, amino acid supplementation, particularly with leucine, has received a lot of attention. Supplementation has been shown to have remarkable effects on muscle remodeling through protein turnover modulation. This may then impact physiological parameters related to muscle function, and even quality of life. In light of this, leucine supplementation could be a useful therapy for mitigating the atrophic effects of catabolic conditions. The purpose of this review is to present the major results of human studies evaluating the effects of leucine supplementation on structure and function of skeletal muscle in atrophic conditions such as muscle disuse, sarcopenia, and cancer.
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Leucina/uso terapéutico , Músculo Esquelético/efectos de los fármacos , Músculo Esquelético/patología , Atrofia Muscular/tratamiento farmacológico , Enfermedades Musculares/tratamiento farmacológico , Neoplasias/tratamiento farmacológico , Ensayos Clínicos como Asunto , Suplementos Dietéticos/estadística & datos numéricos , Humanos , Leucina/efectos adversos , Enfermedades Musculares/patologíaRESUMEN
It is well known that carbohydrate (CHO) supplementation can improve performance in endurance exercises through several mechanisms such as maintenance of glycemia and sparing endogenous glycogen as well as the possibility of a central nervous-system action. Some studies have emerged in recent years in order to test the hypothesis of ergogenic action via central nervous system. Recent studies have demonstrated that CHO mouth rinse can lead to improved performance of cyclists, and this may be associated with the activation of brain areas linked to motivation and reward. These findings have already been replicated in other endurance modalities, such as running. This alternative seems to be an attractive nutritional tool to improve endurance exercise performance.
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Carbohidratos/farmacología , Ejercicio Físico/fisiología , Antisépticos Bucales/farmacología , Resistencia Física/efectos de los fármacos , Ciclismo/fisiología , Humanos , Resistencia Física/fisiologíaRESUMEN
Glucocorticoid hormones are important regulators of several physiological processes. Despite having been initially named based on their role in glucose metabolism, glucocorticoids are also fundamental in the regulation of developmental, metabolic, and neurobiological processes, as well as several other biological functions. Due to their involvement in a diverse array of biological pathways, its wide spectrum of action, it is predicted that a wide range of genes may have their expression regulated by the activated glucocorticoid receptor (GR). In fact, it has been demonstrated that in addition to the regulation of several effectors genes, the expression of the gene encoding for GR itself is regulated by physiological stimuli and fine-tuning mechanisms. Importantly, such generalized effector responses and fine-tuning responses seem to be largely mediated by mechanisms of gene regulation. Therefore, this review aims to describe the mechanisms of gene regulation by glucocorticoid hormones, which are capable of regulating differential gene transcription, within a physiological context. From this discussion, we hope to shed light on how a single molecule that is capable of exerting such divergent effects is also capable of promoting such distinct responses in different target tissues.
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Regulación de la Expresión Génica , Glucocorticoides/metabolismo , Animales , Genoma/genética , Humanos , Receptores de Glucocorticoides/genética , Receptores de Glucocorticoides/metabolismo , Proteínas Represoras/metabolismo , Transcripción GenéticaRESUMEN
Judo competitions are divided into weight classes. However, most athletes reduce their body weight in a few days before competition in order to obtain a competitive advantage over lighter opponents. To achieve fast weight reduction, athletes use a number of aggressive nutritional strategies so many of them place themselves at a high health-injury risk. In collegiate wrestling, a similar problem has been observed and three wrestlers died in 1997 due to rapid weight loss regimes. After these deaths, the National Collegiate Athletic Association had implemented a successful weight management program which was proven to improve weight management behavior. No similar program has ever been discussed by judo federations even though judo competitors present a comparable inappropriate pattern of weight control. In view of this, the basis for a weight control program is provided in this manuscript, as follows: competition should begin within 1 hour after weigh-in, at the latest; each athlete is allowed to be weighed-in only once; rapid weight loss as well as artificial rehydration (i.e., saline infusion) methods are prohibited during the entire competition day; athletes should pass the hydration test to get their weigh-in validated; an individual minimum competitive weight (male athletes competing at no less than 7% and females at no less than 12% of body fat) should be determined at the beginning of each season; athletes are not allowed to compete in any weight class that requires weight reductions greater than 1.5% of body weight per week. In parallel, educational programs should aim at increasing the athletes', coaches' and parents' awareness about the risks of aggressive nutritional strategies as well as healthier ways to properly manage body weight.
RESUMEN
Resumo Objetivo: Descrever o perfil antropométrico e a composição corporal de idosos por meio da antropometria, analisando a aplicabilidade das equações de predição de Petroski (1995) e de Durnin & Womersley (1974).Métodos: Foram avaliados 37 idosos de ambos os gêneros. As medições antropométricas foram realizadas segundo as diretrizes daInternational Society for the Advancement of Kineanthropometry, e determinaram as variáveis massa corporal, estatura, oito dobras cutâneas e sete perímetros musculares. Calcularam-se índice de massa corporal (IMC), relação cintura-quadril (RCQ), somatório de cinco dobras cutâneas e densidade corporal pelas equações de predição para idosos de Petroski (1995) e de Durnin & Womersley (1974) com conversão ao percentual de gordura (%G) pela equação de Siri (1961). Para posterior discussão, aplicou-se o teste t Student (p<0,05).Resultados: As variáveis idade, massa corporal, estatura e IMC não diferiram entre os gêneros. O somatório de cinco dobras cutâneas resultou em eutrofia para ambos os gêneros. A RCQ indicou "risco moderado" para homens e "risco alto" para mulheres, de complicações metabólicas. A equação de Durnin & Womersley (1974) subestimou nos indivíduos do gênero masculino e superestimou no gênero feminino o %G obtido pela equação de Petroski (1995), respectivamente. Por ambas as equações, os indivíduos do gênero feminino apresentaram %G superior aos do gênero masculino. Conclusões:Os indivíduos de ambos os gêneros apresentam elevada adiposidade corporal, especialmente na região omental. A equação de Petroski (1995) atendeu de modo satisfatório aos critérios de aplicação utilizados e mostrou ser adequada para a população em questão.
Abstract Objective: To describe anthropometric profile and body composition of elderly by anthropometry and evaluate the applicability of Petroski (1995) and Durnin & Womerseley (1974) protocols.Methods: We evaluated 37 elderly individuals of both genders. The anthropometric measurements were performed according to the guidelines of the International Society for the Advancement of Kineanthropometry and established the variables weight, height, eight skinfolds and seven muscle girths. It was calculated body mass index (BMI), waist-to-hip ratio (WHR), sum of five skinfolds and body density by Petroski (1995) and Durnin & Womersley (1974) elderly protocols with the conversion to percentage of body fat (%BF) by Siri (1961) protocol. For further discussion, it was applied the Studentt test (p<0.05). Results: Age, weight, height and BMI did not differ between genders. The sum of five skinfolds resulted in normal range for both genders. The WHR indicated "moderate risk" for men, and "high risk" for women to develop metabolic complications. The Durnin & Womersley (1974) protocol underestimated in male subjects and overestimated in female subjects the %BF obtained by the equation of Petroski (1995), respectively. For both protocols, female subjects showed higher %BF than male subjects. Conclusions: We conclude that individuals of both genders have high body fat, especially in the abdominal region. The Petroski (1995) protocol answered satisfactorily to the applying criteria used and showed to be adequate for this population.
RESUMEN
The number of individuals with excess body weight has been growingalarmingly in recent times, a fact attributed, in part, to changes in the quality of the diet consumed. The nutritional knowledge has been suggested by some researches to be able to directly infl uence food selection, and possibly may be associated with nutritional status. So, the objective of this study was to evaluate the association of nutritional knowledge level with Body Mass Index and levelof education. The sample consisted of 42 male (n=9) and female (n=33)individuals, aged 24-59 years, who were receiving nutritional monitoring ina rehabilitation center located in Sao Paulo city, Brazil. The anthropometricdata measured were body weight and height, and the Body Mass Index (bodyweight/height2) was calculated. The nutrition knowledge was measuredusing a previously validated questionnaire for the Brazilian population. It was possible to check that, generally, both groups showed moderate and low nutrition knowledge, and women had a signifi cantly higher score than men (p<0.05). However, no signifi cant correlation between the questionnaire score and the Body Mass Index were observed (r=0.16), while the latter was positively correlated with the degree of education (r=0.31, p<0.05). The results suggest that the nutritional knowledge does not seem to be determinant in food selection, and highlights the importance of nutrition strategies aimed to incorporating nutritional knowledge in promoting healthy habits.
El número de personas con exceso de peso corporal ha crecido de manera alarmante enlos últimos tiempos, un hecho atribuido, en parte, a los cambios en la calidad de la dieta consumida. El conocimiento nutricional de la población ha sido propuesto por algunos sondeos como un indicador capaz de influirdirectamente en la selección de alimentos por las personas, refl ejándose probablemente en su estadonutricional. El objetivo de este estudio fue evaluar la asociación entre el nivel de conocimiento nutricional, el Índice de Masa Corporal y la escolaridad. La muestra para este trabajo estuvocompuesta de 42 personas, nueve hombres y 33 mujeres, con edades comprendidas entre 24 y 59 años, que efectuaban acompañamientonutricional en un centro de rehabilitaciónubicado en São Paulo, Brasil. Los datosantropométricos medidos fueron peso y altura, calculándose el Índice de Masa Corporal (peso corporal/altura2). El conocimiento nutricional fue evaluado utilizando un cuestionario previamente validado para la poblaciónbrasileña. En general, es posible observar que ambos grupos mostraron conocimiento nutricional entre bajo y moderado, las mujeres con una puntuación significativamentemayor que los hombres (p<0,05). Sin embargo, no hay correlación significativa entre la puntuación en el cuestionario y el Índice de Masa Corporal (r=0,16), mientras el cuestionario se correlacionó positivamente con el grado deeducación (r=0,31, p<0,05). Los resultados sugieren que el conocimiento de nutrición no parece ser determinante para la selección de alimentos, resaltando que la incorporación deeste conocimiento es una estrategia nutricional importante en la promoción de hábitos saludables.
O número de indivíduos com excesso de peso corporal vem crescendo de maneira preocupante nos últimos tempos, fato este atribuído, emparte, pelas mudanças na qualidade da dieta consumida. O conhecimento nutricional vem sendo proposto por algumas pesquisas como umindicador capaz de influenciar diretamente a seleção alimentar e, possivelmente, se associarcom o estado nutricional. Dessa forma, o objetivo do presente estudo foi avaliar a associação do nível de conhecimento nutricional com o Índice de Massa Corporal e escolaridade. A amostra foicomposta por 42 indivíduos do gênero masculino (n=9) e feminino (n=33), com idade entre 24 e 59 anos, que realizavam acompanhamento nutricional em um centro de reabilitaçãolocalizado no município de São Paulo, Brasil. Os dados antropométricos mensurados foram peso corporal, estatura e calculado o Índice de Massa Corporal (peso corporal/estatura2).O conhecimento nutricional foi mensurado por meio de um questionário previamente validado para a população brasileira. Foi possível observar que, de modo geral, ambos os grupos apresentaram conhecimento nutricional baixo e moderado, sendo mulheres com a pontuação significativamente maior que homens (p<0,05).Porém, não houve correlação significativa entre a pontuação obtida no questionário com o Índice de Massa Corporal (r=0,16), enquantoque essa foi positivamente correlacionada com o grau de escolaridade (r=0,31; p<0,05). Osresultados obtidos sugerem que o conhecimento nutricional pareça não ser determinante na seleção alimentar, destacando-se assim aimportância de estratégias nutricionais que visem à incorporação do conhecimento em nutrição na promoção de hábitos saudáveis.