RESUMO
Although it is well established that fibromyalgia (FM) syndrome is characterized by chronic diffuse musculoskeletal hyperalgesia, very little is known about the effect of this pathology on muscle tissue plasticity. Therefore, the present study aimed to characterize the putative alterations in skeletal muscle mass in female rats subjected to a FM model by inducing chronic diffuse hyperalgesia (CDH) through double injections of acidic saline (pH 4.0) into the left gastrocnemius muscle at 5-day intervals. To determine protein turnover, the total proteolysis, proteolytic system activities and protein synthesis were evaluated in oxidative soleus muscles of pH 7.2 (control) and pH 4.0 groups at 7 days after CDH induction. All animals underwent behavioural analyses of mechanical hyperalgesia, strength and motor performance. Our results demonstrated that, in addition to hyperalgesia, rats injected with acidic saline exhibited skeletal muscle loss, as evidenced by a decrease in the soleus fibre cross-sectional area. This muscle loss was associated with increased proteasomal proteolysis and expression of the atrophy-related gene (muscle RING-finger protein-1), as well as reduced protein synthesis and decreased protein kinase B/S6 pathway activity. Although the plasma corticosterone concentration did not differ between the control and pH 4.0 groups, the removal of the adrenal glands attenuated hyperalgesia, but it did not prevent the increase in muscle protein loss in acidic saline-injected animals. The data suggests that the stress-related hypothalamic-pituitary-adrenal axis is involved in the development of hyperalgesia, but is not responsible for muscle atrophy observed in the FM model induced by intramuscular administration of acidic saline. Although the mechanisms involved in the attenuation of hyperalgesia in rats injected with acidic saline and subjected to adrenalectomy still need to be elucidated, the results found in this study suggest that glucocorticoids may not represent an effective therapeutic approach to alleviate FM symptoms.
Assuntos
Fibromialgia , Hiperalgesia , Ratos , Feminino , Animais , Hiperalgesia/tratamento farmacológico , Fibromialgia/complicações , Fibromialgia/tratamento farmacológico , Fibromialgia/patologia , Adrenalectomia , Sistema Hipotálamo-Hipofisário/metabolismo , Sistema Hipotálamo-Hipofisário/patologia , Sistema Hipófise-Suprarrenal/metabolismo , Sistema Hipófise-Suprarrenal/patologia , Músculo Esquelético/metabolismo , Atrofia Muscular/patologia , Solução Salina/farmacologiaRESUMO
BACKGROUND: Persistent inflammation, immunosuppression and catabolism syndrome (PICS) has been described in critically ill adults and may contribute to unfavourable outcomes. The present study aimed to describe and characterise PICS in critically ill children (PICS-ped) and to verify its association with clinical outcomes. METHODS: A prospective longitudinal study was conducted in a paediatric intensive care unit (PICU) with children aged between 3 months and 15 years. PICS-ped, based on adult definition, was described. PICS-ped was defined as PICU length of stay >14 days; C-reactive protein > 10.0 mg L-1 ; lymphocytes <25%; and any reduction of mid-upper arm circumference Z-score. Clinical, demographic, nutritional status, nutrition therapy parameters and clinical outcomes were assessed. Statistical analysis comprised Mann-Whitney and Fisher's chi-squared tests, as well as logistic and Cox regression. P < 0.05 was considered statistically significant. RESULTS: In total, 153 children were included, with a median age of 51.7 months (interquartile range 15.6-123.4 months), and 60.8% male. The mortality rate was 10.5%. The prevalence of PICS-ped was 4.6%. Days using vasoactive drugs and days using antibiotics were associated with PICS-ped. PICS-ped was associated with mortality in crude (odds ratio = 6.67; P = 0.013) and adjusted analysis (odds ratio = 7.14; P = 0.017). PICS-ped was also associated with PICU and hospital length of stay, as well as duration of mechanical ventilation. Similar results were found in a subset of critically ill children who required mechanical ventilation for more than 48 h. CONCLUSIONS: Children with PICS-ped required antibiotics or vasoactive drugs for a longer period. PICS-ped was associated with poor clinical outcomes in critically ill children. More studies are needed to properly define PICS-ped for this population.
Assuntos
Estado Terminal , Terapia de Imunossupressão , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Inflamação , Tempo de Internação , Estudos Longitudinais , Masculino , Estudos ProspectivosRESUMO
The interactions between liposomes and fish myofibrillar protein (surimi ground salted protein, SURP) were evaluated. Liposomes prepared with ultrapure phosphatidylcholine (UPC) or partially purified phosphatidylcholine (PPC) were dispersed at different weight ratio on SURP. Changes in protein stability and structure were evaluated using FTIR, intrinsic fluorescence and free sulfhydryl groups, and changes in liposome properties were studied by dynamic light scattering and electron microscopy. PPC promoted denaturation and aggregation of SURP, reflected in secondary structure loss, exposure of tyrosine residues and increment of free sulfhydryl. UPC produced partial unfolding and changes in the secondary structure of SURP from α-helical to ß-strand. Liposome size increased by about 40% and showed modified surface charge after SURP exposure, indicating the formation of protein corona. Surface charge and composition of liposomes influence SURP stability and could exert different effects on the myofibrillar protein network, which is important for liposome applications in surimi products.
Assuntos
Proteínas de Peixes , Lipossomos , Animais , Lecitinas , Estrutura Secundária de Proteína , ProteínasRESUMO
Omega-3 (ω-3) is a polyunsaturated fatty acid with anti-inflammatory properties that presents three main forms: alpha-linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid. Recently, studies performed in both young and older adults suggest that ω-3 may improve gains in muscle mass and/or enhance physical function. Thus, the aim of this narrative review was to evaluate the current evidence of ω-3 intake/supplementation on muscle/lean mass (LM) and physical function in young and older adults, and draw research-based conclusions as to the practical implications of findings. We first assessed whether ω-3 intake is associated with muscle mass and strength (observational studies), and then sought to determine whether evidence shows that supplementation of ω-3 increases muscle protein synthesis, LM and strength in adults and older adults (interventional studies). The search was carried out in PubMed and Scopus databases for the periods between 1997 and November 2018. The following keywords were used alone and in combination: ω-3, fish oil, muscle protein synthesis, muscle mass, lean mass, body composition, and physical function. In general, the evidence is mixed as to the effects of ω-3 supplementation on muscle mass in sedentary young and older adults; the hypertrophic effects of supplementation when combined with resistance training remain equivocal. Moreover, there is conflicting evidence as to whether supplementation confers a beneficial effect on muscle function in older adults. Importantly, this conclusion is based on limited data and more studies are needed before ω-3 supplementation can be recommended as a viable strategy for such purposes in clinical practice.
Assuntos
Composição Corporal/efeitos dos fármacos , Suplementos Nutricionais , Ácidos Graxos Ômega-3/administração & dosagem , Força Muscular/efeitos dos fármacos , Músculo Esquelético/efeitos dos fármacos , Adulto , Fatores Etários , Idoso , Ácidos Graxos Ômega-3/farmacologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
The manipulation of resistance training (RT) variables is used among athletes, recreational exercisers, and compromised populations (e.g., elderly) attempting to potentiate muscle hypertrophy. However, it is unknown whether an individual's inherent predisposition dictates the RT-induced muscle hypertrophic response. Resistance-trained young [26 (3) y] men (n = 20) performed 8 wk unilateral RT (2 times/wk), with 1 leg randomly assigned to a standard progressive RT [control (CON)] and the contralateral leg to a variable RT (VAR; modulating exercise load, volume, contraction type, and interset rest interval). The VAR leg completed all 4 RT variations every 2 wk. Bilateral vastus lateralis cross-sectional area (CSA) was measured, pre- and post-RT and acute integrated myofibrillar protein synthesis (MyoPS) rates were assessed at rest and over 48 h following the final RT session. Muscle CSA increase was similar between CON and VAR (P > 0.05), despite higher total training volume (TTV) in VAR (P < 0.05). The 0-48-h integrated MyoPS increase postexercise was slightly greater for VAR than CON (P < 0.05). All participants were considered "responders" to RT, although none benefited to a greater extent from a specific protocol. Between-subjects variability (MyoPS, 3.30%; CSA, 37.8%) was 40-fold greater than the intrasubject (between legs) variability (MyoPS, 0.08%; CSA, 0.9%). The higher TTV and greater MyoPS response in VAR did not translate to a greater muscle hypertrophic response. Manipulating common RT variables elicited similar muscle hypertrophy than a standard progressive RT program in trained young men. Intrinsic individual factors are key determinants of the MyoPS and change in muscle CSA compared with extrinsic manipulation of common RT variables.NEW & NOTEWORTHY Systematically manipulating resistance training (RT) variables during RT augments the stimulation of myofibrillar protein synthesis (MyoPS) and training volume but fails to potentiate muscle hypertrophy compared with a standard progressive RT. Any modest further MyoPS increase and higher training volumes do not reflect in a greater hypertrophic response. Between-subject variability was 40-fold greater than the variability promoted by extrinsic manipulation of RT variables, indicating that individual intrinsic factors are stronger determinants of the hypertrophic response.
Assuntos
Proteínas Musculares/biossíntese , Músculo Quadríceps/metabolismo , Treinamento Resistido/métodos , Adulto , Humanos , Hipertrofia , Masculino , Adulto JovemRESUMO
Cachexia syndrome can affect cancer patients and new prevention strategies are required. Maternal nutritional supplementation can modify metabolic programming in the offspring, which lasts until adulthood. This could be a good approach against diseases such as cancer. A 3% leucine-rich diet treatment improved muscle protein turnover by modifying the mTOR and proteolytic pathways, thus we analysed whether maternal supplementation could ameliorate muscle protein turnover in adult offspring tumour-bearing rats. Pregnant Wistar rats received a control diet or 3% leucine-rich diet during pregnancy/lactation, and their weaned male offspring received a control diet until adulthood when they were distributed into following groups (n = 7-8 per group): C, Control; W, tumour-bearing; L, without tumour with a maternal leucine-rich diet; and WL, tumour-bearing with a maternal leucine-rich diet. Protein synthesis and degradation were assessed in the gastrocnemius muscle, focusing on the mTOR pathway, which was extensively altered in W group. However, the WL adult offspring showed no decrease in muscle weight, higher food intake, ameliorated muscle turnover, activated mTOR and p70S6K, and maintained muscle cathepsin H and calpain activities. Maternal leucine nutritional supplementation could be a positive strategy to improve muscle protein balance in cancer cachexia-induced muscle damage in adult offspring rats.
Assuntos
Caquexia/complicações , Dieta , Leucina/análise , Mães , Proteínas Musculares/biossíntese , Proteínas Musculares/metabolismo , Músculos/efeitos dos fármacos , Animais , Peso Corporal/efeitos dos fármacos , Caquexia/metabolismo , Caquexia/patologia , Ingestão de Alimentos/efeitos dos fármacos , Feminino , Masculino , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Músculos/metabolismo , Músculos/patologia , Neoplasias/complicações , Tamanho do Órgão/efeitos dos fármacos , Gravidez , Proteólise/efeitos dos fármacos , Ratos , Ratos WistarRESUMO
BACKGROUND: Gene expression is an important process underpinning the acute and chronic adaptive response to resistance exercise (RE) training. PURPOSE: To investigate the effect of training status on vastus lateralis muscle global transcriptome at rest and following acute RE. METHODS: Muscle biopsies of nine young men (age: 26(2) years; body mass: 69(9) kg; height 172(6) cm) who undertook RE training for 10 weeks were collected pre and 24 h post-RE in the untrained (W1) and trained (W10) states and analysed using microarray. Tests of differential expression were conducted for rested and after RE contrasts in both training states. To control for false discovery rate (FDR), multiple testing correction was performed at a cut-off of FDR < 0.05. RESULTS: Unaccustomed RE (at W1) upregulated muscle gene transcripts related to stress (e.g., heat shock proteins), damage and inflammation, structural remodelling, protein turnover and increased translational capacity. Trained muscles (at W10) showed changes in the transcriptome signature regarding the regulation of energy metabolism, favouring a more oxidative one, upregulated antioxidant- and immune-related genes/terms, and gene transcripts related to the cytoskeleton and extracellular matrix, muscle contraction, development and growth. CONCLUSIONS: These results highlight that chronic repetition of RE changes muscle transcriptome response towards a more refined response to RE-induced stress.
Assuntos
Músculo Esquelético/metabolismo , Treinamento Resistido , Estresse Fisiológico , Transcriptoma , Adulto , Humanos , Masculino , Músculo Esquelético/anatomia & histologia , Músculo Esquelético/fisiologiaRESUMO
Um número crescente de pesquisas envolvendo a suplementação de aminoácidos isolados sobre o desempenho físico vem sendo realizado, mas os efeitos e os possíveis mecanismos de ação de muitos deles ainda permanecem inconclusivos. Destes, um aminoácido que vem sendo amplamente estudado, e que já faz parte da composição de inúmeros suplementos nutricionais, é a L-arginina pelo seu possível papel na estimulação da secreção do hormônio do crescimento (GH) e da insulina, além de ser um indutor da vasodilatação dependente de óxido nítrico (NO). Diversos estudos indicam que a suplementação de L-arginina pode estimular signifi cativa secreção do GH no repouso e, quando associada ao exercício, pode promover um feedback hipotalâmico negativo com conseqüente diminuição da secreção deste hormônio. A síntese protéica muscular tem sido associado à vasodilatação promovida pela L-arginina o que, em parte, pode ser considerado errôneo pelo fato desta isoladamente não aumentar a disponibilidade de substratos para recuperação muscular. Contudo, estudos que envolvem L-arginina e desempenho esportivo, bem como aqueles investigam dose e tempo de consumo desse aminoácido, são confl itantes e refl etem a escassez de trabalhos nesse contexto. A presente revisão descreve os aspectos metabólicos e possíveis efeitos ergogênicos da suplementação de L-arginina sobre o exercício físico.
A growing number of studies involving isolated aminoacids supplementation on physical performance have been achieved, but the effects and possible mechanisms of action of many of them still remain unclear. Of these, an amino acid that has been widely studied, and that is already part of the composition of many nutritional supplements, is L-arginine for its possible role in stimulating growth hormone (GH) and insulin release, beyond to be a nitric oxide dependent vasodilation inducer (NO). Several studies indicate that L-arginine supplementation can signifi cantly stimulate basal GH release and, when associated with exercise, can promote a negative hypothalamic feedback with consequent attenuation of release. Skeletal muscle protein synthesis has been associated with L-arginine-induced vasodilation which, in part, can be considered erroneous because alone it does not increase substrates availability for muscle recovery. However, studies involving L-arginine and exercise performance, as well as those investigating dose and time of consumption of this aminoacid are confl icting and refl ect the shortage of works in this context. This review describes the metabolic aspects and possible ergogenic effects of L-arginine supplementation on exercise.
Assuntos
Humanos , Aminoácidos , Arginina , Desempenho Atlético , Hormônio do Crescimento , Insulina , Óxido Nítrico , Substâncias para Melhoria do DesempenhoRESUMO
The objective of this study was to evaluate the effect of clenbuterol (CB), a beta2-adrenergic agonist, as a growth and weight gain promoter in broilers. Effects of CB were assessed, mixing it in feed at 0.0, 0.21, 0.42 and 0.84ppm, and feeding during four weeks to four groups (n=75) of 28 day-old Arbor Acres chickens. The body weight (BW) and food intake at 0, 12, 20 and 28 days of the study were recorded. Also abdominal fat (AF) and total muscle proteins were measured. Results indicate that from day 20 until the last of the experimental period (56-day-old), efficacy of CB was evident to increase growth and decrease AF deposition rates (P 0.01), in a dose-response pattern, suggesting that CB has a profitable growth promoting effect in broiler chickens.
Avaliou-se o efeito da administração de clenbuterol (CB) como promotor de ganho de peso em frangos, dos 28 (início do experimento) aos 56 dias de idade (final do experimento). CB foi adicionado às dietas nas dosagens de 0 (controle), 0,21, 0,42 e 0,84ppm. Utilizaram-se 75 frangos em cada tratamento, registrando-se o peso corporal, o consumo de alimento, a gordura abdominal e a proteína muscular. A partir do 20º dia do experimento (48 dias de idade) até o seu final o efeito da administração de CB foi significativo. Frangos que receberam dosagens mais elevadas de CB estavam mais pesados. Observou-se também diminuição na deposição de gordura no abdômen com o aumento das dosagens de CB na dieta.
RESUMO
The objective of this study was to evaluate the effect of clenbuterol (CB), a beta2-adrenergic agonist, as a growth and weight gain promoter in broilers. Effects of CB were assessed, mixing it in feed at 0.0, 0.21, 0.42 and 0.84ppm, and feeding during four weeks to four groups (n=75) of 28 day-old Arbor Acres chickens. The body weight (BW) and food intake at 0, 12, 20 and 28 days of the study were recorded. Also abdominal fat (AF) and total muscle proteins were measured. Results indicate that from day 20 until the last of the experimental period (56-day-old), efficacy of CB was evident to increase growth and decrease AF deposition rates (P 0.01), in a dose-response pattern, suggesting that CB has a profitable growth promoting effect in broiler chickens.
Avaliou-se o efeito da administração de clenbuterol (CB) como promotor de ganho de peso em frangos, dos 28 (início do experimento) aos 56 dias de idade (final do experimento). CB foi adicionado às dietas nas dosagens de 0 (controle), 0,21, 0,42 e 0,84ppm. Utilizaram-se 75 frangos em cada tratamento, registrando-se o peso corporal, o consumo de alimento, a gordura abdominal e a proteína muscular. A partir do 20º dia do experimento (48 dias de idade) até o seu final o efeito da administração de CB foi significativo. Frangos que receberam dosagens mais elevadas de CB estavam mais pesados. Observou-se também diminuição na deposição de gordura no abdômen com o aumento das dosagens de CB na dieta.