Imaging of Existing and Newly Translated Proteins Elucidates Mechanisms of Sarcomere Turnover.

BACKGROUND: How the sarcomeric complex is continuously turned over in long-living cardiomyocytes is unclear. According to the prevailing model of sarcomere maintenance, sarcomeres are maintained by cytoplasmic soluble protein pools with free recycling between pools and sarcomeres. METHODS: We imaged and quantified the turnover of expressed and endogenous sarcomeric proteins, including the giant protein titin, in cardiomyocytes in culture and in vivo, at the single cell and at the single sarcomere level using pulse-chase labeling of Halo-tagged proteins with covalent ligands. RESULTS: We disprove the prevailing protein pool model and instead show an ordered mechanism in which only newly translated proteins enter the sarcomeric complex while older ones are removed and degraded. We also show that degradation is independent of protein age and that proteolytic extraction is a rate-limiting step in the turnover. We show that replacement of sarcomeric proteins occurs at a similar rate within cells and across the heart and is slower in adult cells. CONCLUSIONS: Our findings establish a unidirectional replacement model for cardiac sarcomeres subunit replacement and identify their turnover principles.

Molecular Localization of Health-Promoting Peptides Derived from Fish Protein Hydrolyzates on Fish Muscle Proteins.

The four previously reported health-promoting dipeptides, valine-tyrosine, lysine-tryptophan, methionine-phenylalanine, and arginine-isoleucine, found in the fish muscle hydrolyzates, were mainly located in the myosin subfragment-1 heavy chain, whereas the health-promoting tripeptide, alanine-lysine-lysine, was found in the fibrous rod consisting of the myosin subfragment-2 and light meromyosin with a regular coiled-coil structure of α-helix, irrespective of the fish species. Furthermore, the localization of these peptides either in the random coil, ß-sheet, or α-helix was also examined in the three-dimensional image, showing no specific tendency. Surprisingly, the same trend was observed even for the mammalian rabbit fast muscle myosin heavy chain. Since a trade-off between myofibrillar ATPase and structural stability has been reported for fish living at low environmental temperatures, it is speculated that fish muscle proteins, when ingested, are easily digested by various proteases in the human digestive tract and provide various health-promoting peptides also in vivo. While fish actin contained only two dipeptides, methionine-phenylalanine and valine-tyrosine, glyceraldehyde 3-phosphate dehydrogenase, one of the major components of fish muscle water-soluble protein, contained all of the four dipeptides and one tripeptide mentioned above.

Effects of Low-Load Blood Flow Restriction Training on Muscle Anabolism Biomarkers and Thrombotic Biomarkers Compared with Traditional Training in Healthy Adults Older Than 60 Years: Systematic Review and Meta-Analysis.

The aim of this meta-analysis was to determine the effects of low-load blood flow restriction training (LL-BFRT) on muscle anabolism and thrombotic biomarkers compared with the effects of traditional LL training and to analyse the changes in these biomarkers in the short and medium term (acute/immediate and after at least 4 weeks of the training programme, respectively). A search was conducted in the following electronic databases from inception to 1 March 2024: MEDLINE, CENTRAL, Web of Science, PEDro, Science Direct, CINHAL, and Scopus. A total of 13 randomized controlled trials were included, with a total of 256 healthy older adults (mean (min-max) age 68 (62-71) years, 44.53% female). The outcome measures were muscle anabolism biomarkers and thrombosis biomarkers. The standardized mean difference (SMD) was calculated to compare the outcomes reported by the studies. The overall meta-analysis showed that LL-BFRT produces a large increase in muscle anabolism biomarkers compared with traditional LL training (eight studies; SMD = 0.88 [0.39; 1.37]) and compared with a passive control (four studies; SMD = 0.91 [0.54; 1.29]). LL-BFRT does not produce an increase in thrombotic biomarkers compared with traditional LL training (four studies; SMD = -0.02 [-0.41; 0.36]) or compared with a passive control (two studies; SMD = 0.20 [-0.41; 0.80]). The increase in muscle anabolism biomarkers was large after applying a single session (four studies; SMD = 1.29 [0.18; 2.41]) and moderate after applying a training programme (four studies; SMD = 0.58 [0.09; 1.06]). In conclusion, LL-BFRT increases muscle anabolism biomarkers to a greater extent than traditional LL training (low-quality evidence) or a passive control (moderate-quality evidence) in healthy older adults. This superior anabolic potential of LL-BFRT compared with LL training is sustained in the short to medium term. LL-BFRT is a safe training methodology for older adults, showing moderate-quality evidence of no increase in thrombotic biomarkers compared with traditional LL training.

Sex differences in neuromuscular and biological determinants of isometric maximal force.

AIM: Force expression is characterized by an interplay of biological and molecular determinants that are expected to differentiate males and females in terms of maximal performance. These include muscle characteristics (muscle size, fiber type, contractility), neuromuscular regulation (central and peripheral factors of force expression), and individual genetic factors (miRNAs and gene/protein expression). This research aims to comprehensively assess these physiological variables and their role as determinants of maximal force difference between sexes. METHODS: Experimental evaluations include neuromuscular components of isometric contraction, intrinsic muscle characteristics (proteins and fiber type), and some biomarkers associated with muscle function (circulating miRNAs and gut microbiome) in 12 young and healthy males and 12 females. RESULTS: Male strength superiority appears to stem primarily from muscle size while muscle fiber-type distribution plays a crucial role in contractile properties. Moderate-to-strong pooled correlations between these muscle parameters were established with specific circulating miRNAs, as well as muscle and plasma proteins. CONCLUSION: Muscle size is crucial in explaining the differences in maximal voluntary isometric force generation between males and females with similar fiber type distribution. Potential physiological mechanisms are seen from associations between maximal force, skeletal muscle contractile properties, and biological markers.

Fuerza prensil y composición corporal en escolares colombianos. Estudio piloto

Introducción: Algunos estudios han encontrado relación entre exceso de peso y baja fuerza de prensión relativa. En países de ingresos socioeconómicos medianos y bajos hay pocas evidencias que evalúen la fuerza prensil y su relación con la composición corporal en población pediátrica. Objetivo: Evaluar la correlación entre la fuerza prensil y la composición corporal de escolares de Bucaramanga, Colombia. Materiales y métodos: Se realizó un estudio piloto de corte transversal, analítico, correlacional. Participaron niños en edad escolar de Bucaramanga, Colombia. Las principales variables dependientes fueron masa muscular, agua corporal total, proteínas (kg) y el porcentaje de grasa corporal. La variable independiente correspondió a la fuerza prensil. Se usó el coeficiente de correlación de Spearman para explorar la relación entre variables. Resultados: El promedio de la fuerza prensil en el total de la muestra fue de 13,8 ± 3,2 Newton. Se encontraron correlaciones positivas y estadísticamente significativas entre la fuerza prensil y la masa musculoesquelética (r = 0,73), agua corporal total (r = 0,73) y proteínas (r = 0,74). Discusión: Nuestros resultados son consistentes con evidencias previas que identifican a la fuerza prensil como un indicador de la composición corporal, específicamente en las variables de masa musculoesquelética y proteínas. Conclusión: Los niños en el tercil más alto de fuerza prensil presentan los terciles más altos de masa musculoesquelética, agua corporal total y proteínas.

Introduction: Some studies have found a relationship between excess weight and low relative grip strength. In countries with medium and low socioeconomic income, there is little evidence evaluating grip strength and its relationship with body composition in the pediatric population. Objective: To evaluate the correlation between grip strength and body composition of schoolchildren from Bucaramanga, Colombia. Materials and Methods: A cross-sectional, analytical, correlational pilot study was conducted. Schoolchildren from Bucaramanga, Colombia participated. The main dependent variables were muscle mass, total body water, protein (kg), and percentage of body fat. The independent variable corresponded to the prehensile force. Spearman's Correlation Coefficient was used to explore the relationship between variables. Results: The average prehensile force in the total sample was 13.8±3.2 Newton. Positive and statistically significant correlations were found between grip strength and musculoskeletal mass (r=0.73), total body water (r=0.73), and protein (r=0.74). Discussion: Our results are consistent with previous evidence that identifies grip strength as an indicator of body composition, specifically in the variables of musculoskeletal mass and protein. Conclusion: Children in the highest tertile of prehensile strength present the highest tertiles of skeletal muscle mass, total body water, and protein.

Investigating the migration hypothesis: Effects of trypsin-like protease on the quality of muscle proteins of red shrimp (Solenocera crassicornis) during cold storage.

This study aimed to investigate the effect of trypsin-like protease (TLP) on the quality of muscle proteins in red shrimp (Solenocera crassicornis) during cold storage. The results indicated that the activity of TLP decreased significantly in the head of shrimp but increased significantly in the muscle tissues during the cold storage. The myofibril fragmentation index (MFI) value of intact shrimp was significantly higher than that of beheaded shrimp, while the Ca2+-ATPase activity of intact shrimp was significantly lower than that of beheaded shrimp. SDS-PAGE analysis showed that the molecular weight of purified TLP from the shrimp head was about 24 kDa, and the TLP showed high activity at 50 °C and pH 8, indicating that the TLP belongs to the trypsin family. Results from in vitro simulation experiments indicated that the process of TLP incubation significantly reduced the particle size and enlarged the distribution of myofibrillar proteins (MPs) in shrimp muscle tissues. The comparisons were made with respect to the control samples. It can be inferred that TLP migrated from the shrimp head to the muscle tissues during storage and thus promoted the degradation of MPs in red shrimp. The beheading treatment could be an effective mean to maintain better quality and extend the commercialization of shrimp products.

Crystallisation and characterisation of muscle proteins: a mini-review.

The techniques of X-ray protein crystallography, NMR and high-resolution cryo-electron microscopy have all been used to determine the high-resolution structure of proteins. The most-commonly used method, however, remains X-ray crystallography but it does rely heavily on the production of suitable crystals. Indeed, the production of diffraction quality crystals remains the rate-limiting step for most protein systems. This mini-review highlights the crystallisation trials that used existing and newly developed crystallisation methods on two muscle protein targets - the actin binding domain (ABD) of α-actinin and the C0-C1 domain of human cardiac myosin binding protein C (cMyBP-C). Furthermore, using heterogenous nucleating agents the crystallisation of the C1 domain of cMyBP-C was successfully achieved in house along with preliminary actin binding studies using electron microscopy and co-sedimentation assays .

A proteomic approach to identify biomarkers of foal meat quality: A focus on tenderness, color and intramuscular fat traits.

Foal meat is considered a healthy alternative to other meat sources and more environmentally sustainable. However, its quality is highly variable and there is lack of knowledge about the molecular mechanisms underlying its determination. Genotype and diet play a relevant role as the main factors that can allow a control of the final quality and the use of high-throughput analytical methods such as proteomics is a way to achieve this lofty goal. This research aimed to study-two breeds (Burguete and Jaca Navarra) supplemented with two different finishing diets: conventional concentrate and straw (C) vs silage and organic feed (S). The proteomic approach built a library of 294 proteins that were subjected to several statistical and bioinformatic analyses. Burguete breed finished with concentrate produced higher meat quality in terms of tenderness, intramuscular fat and color lightness mainly due to the high abundance of energy metabolic proteins. Tenderness was correlated to myofibrillar proteins (ACTA1, MYBPH, MYL1 and TNNC1) and energy metabolic proteins (ALDOA, CKM, TPI1 and PGMA2). Regarding color, the main pathways were energy metabolism, involving several glycolytic enzymes (ALDOA, PKM, PFKM and CKM). Oxidative stress and response to stress proteins (HSPA1A, SOD2 and PRDX2) were further involved in color variation. Moreover, we revealed that several proteins were related to the intramuscular fat accordingly to the breed. This study proposed several candidate protein biomarkers for foal meat quality that are worthy to evaluate in the future.

Effects of high-intensity gymnastics on skeletal muscle proteins / Efeitos da ginástica de alta intensidade sobre as proteínas musculares esqueléticas / Efectos de la gimnasia de alta intensidad en las proteínas musculares esqueléticas

ABSTRACT Introduction: Although the current method of muscle stretching in gymnastics teaching in colleges and universities can reduce sports fatigue, it has been shown to have little effect on the well-being of athletes because it requires a long recovery time from psychological fatigue. Progressive muscle relaxation training is a method that uses the basic principle of sympathetic nerve activity to reduce the impact of negative emotions psychologically and relieve fatigue physiologically, requiring a further study of its impact on muscle protein. Objective: Explore the effect of high-intensity gymnastics on skeletal muscle protein and study the progressive muscle relaxation training method post-workout adjustment. Methods: After three weeks of training, excluding the standard deviations in the experimental data caused by the athletes' irregular movements, the athletes' blood lactate content and heart rate were counted and recorded. The collected data were analyzed using Excel software to integrate and compare the data using the T-test method. Results: After exercise training, the skeletal muscle function indices of the subjects increased to different degrees. From the point of view of heart rate recovery efficiency, the rate of heart rate decline of progressive relaxation training was higher than that of the two groups, and the degree of fluctuation was lower than that of the two groups, indicating that the level of recovery in heart rate of progressive relaxation training was better. Conclusion: The action of the high-intensity gymnastics team has a good effect on improving the athletes' skeletal muscle and skeletal muscle proteins. Post-exercise conditioning training plays an important role in athletes' physical recovery. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

RESUMO Introdução: Embora o método de alongamento muscular atual no ensino de ginástica em faculdades e universidades consiga reduzir a fadiga esportiva, tem se mostrado pouco eficaz no bem-estar dos atletas por exigir grande tempo de recuperação da fadiga psicológica. O treinamento progressivo de relaxamento muscular é um método que usa o princípio básico da atividade nervosa simpática para reduzir o impacto das emoções negativas psicologicamente e aliviar a fadiga fisiologicamente, necessitando de mais estudos do seu impacto sobre a proteína muscular. Objetivo: Explorar o efeito da ginástica de alta intensidade sobre as proteínas musculares esqueléticas e estudar o método de treinamento progressivo de relaxamento muscular no ajuste pós-treino. Métodos: Após 3 semanas de treinamento, excluídos os desvios-padrão nos dados experimentais causados pelos movimentos irregulares dos atletas, foram contabilizados e registrados os conteúdos de lactato sanguíneo e frequência cardíaca dos atletas. Analisou-se os dados coletados, com o software Excel, para integrar e comparar os dados pelo método de teste-T. Resultados: Após o treinamento do exercício, os índices de função muscular esquelética dos sujeitos aumentaram em diferentes graus. Do ponto de vista da eficiência da recuperação da frequência cardíaca, a taxa de declínio da frequência cardíaca do treinamento de relaxamento progressivo foi maior do que a dos dois grupos, o grau de flutuação foi menor do que o dos dois grupos, indicando que o nível de recuperação na frequência cardíaca do treinamento de relaxamento progressivo foi melhor. Conclusão: A ação da equipe de ginástica de alta intensidade tem um bom efeito na melhoria do músculo esquelético e das proteínas musculares esqueléticas dos atletas. O treinamento de condicionamento pós-exercício desempenha um papel importante na recuperação física dos atletas. Nível de evidência II; Estudos terapêuticos - investigação dos resultados do tratamento.

RESUMEN Introducción: Aunque el método actual de elongación muscular en la enseñanza de la gimnasia en colegios y universidades consigue reducir la fatiga deportiva, se ha demostrado que tiene poco efecto en el bienestar de los atletas porque requiere un largo tiempo de recuperación de la fatiga psicológica. El entrenamiento de la relajación muscular progresiva es un método que utiliza el principio básico de la actividad nerviosa simpática para reducir el impacto de las emociones negativas desde el punto de vista psicológico y aliviar la fatiga desde el punto de vista fisiológico, lo que requiere un estudio más profundo de su impacto en la proteína muscular. Objetivo: Explorar el efecto de la gimnasia de alta intensidad sobre la proteína del músculo esquelético y estudiar el método de entrenamiento de relajación muscular progresiva en el ajuste posterior al entrenamiento. Métodos: Después de 3 semanas de entrenamiento, excluyendo las desviaciones estándar en los datos experimentales causadas por los movimientos irregulares de los atletas, se contó y registró el contenido de lactato en sangre y la frecuencia cardíaca de los atletas. Los datos recogidos se analizaron, con el programa informático Excel, para integrar y comparar los datos mediante el método de la prueba T. Resultados: Tras el entrenamiento con ejercicios, los índices de función del músculo esquelético de los sujetos aumentaron en diferentes grados. Desde el punto de vista de la eficacia de la recuperación de la frecuencia cardíaca, el índice de disminución de la frecuencia cardíaca del entrenamiento de relajación progresiva fue mayor que el de los dos grupos, el grado de fluctuación fue menor que el de los dos grupos, lo que indica que el nivel de recuperación de la frecuencia cardíaca del entrenamiento de relajación progresiva fue mejor. Conclusión: La acción del equipo de gimnasia de alta intensidad tiene un buen efecto en la mejora del músculo esquelético y de las proteínas del músculo esquelético de los atletas. El entrenamiento de acondicionamiento posterior al ejercicio desempeña un papel importante en la recuperación física de los deportistas. Nivel de evidencia II; Estudios terapéuticos - investigación de los resultados del tratamiento.

Effect of Stable Chlorine Dioxide and Vacuum-Packing Treatments on the Physicochemical and Volatile Flavor Properties of Pike Eel (Muraenesox cinereus) during Chilled Storage.

The effects of vacuum-packaging and stable chlorine dioxide treatments on the quality of pike-eel fillets were investigated during chilled storage for a period of up to 10 days. The results reveal that the sensory scores, total volatile basic nitrogen (TVB-N) content, total viable count (TVC), malondialdehyde (MDA) content, and the myofibrillar protein (MP) content of pike-eel fillets with different packing treatments all decreased significantly over 10 days of storage. However, the vacuum-packaging and stable chlorine dioxide pretreatment showed positive effects on the protein stability of pike-eel samples. Compared with the simple packaging (SP) and vacuum packing (VP) treatments, the combination treatments (CP) significantly inhibited the rapid increases in the TVB-N content, TVC values, and MDA content. Moreover, the comparative stability in the MP and its carbonyl content were maintained. Furthermore, our volatile organic compounds (VOCs) analysis confirmed that the combined packaging treatments significantly hindered protein and lipid oxidation, inhibited the growth of spoilage bacteria, and maintained the volatile flavors of pike-eel samples during chilled storage.

Rehabilitation therapy for a severe case of coronavirus disease 2019: a case report.

BACKGROUND: Patients with severe coronavirus disease 2019 (COVID-19) infection require a long period of time to return to work and society due to significant physical weakness even after recovery. Here we report a patient with a history of nephrectomy who developed severe COVID-19 infection associated with muscle weakness but was able to return to society after rehabilitation therapy. CASE PRESENTATION: A Japanese man in his 40s was admitted to the hospital with PCR-based COVID-19 diagnosis. The respiratory condition worsened rapidly and was treated with extracorporeal membrane-assisted ventilation in the intensive case unit. On admission to the Rehabilitation Department on day T + 30 [T: day patient became febrile (38 °C)], he was unable to stand for a long time and used a walker. Rehabilitation therapy was postponed to prevent COVID-19 spread, but the patient was encouraged to exercise during isolation to improve trunk and lower extremity muscle strength. Physical therapy commenced on day T + 49 to improve gait and trunk and lower limb muscle strength. He was able to walk independently and later returned to work following discharge on day T + 53. A computed tomography scan showed an increase in psoas muscle volume from 276 before to 316 cm3 after physical therapy, together with a decrease in whole-body extracellular water:total body weight ratio from 0.394 to 0.389. CONCLUSIONS: We have described the beneficial effects of rehabilitation therapy in a patient with severe COVID-19 infection. In addition to exercise, we believe that nutrition is even more important in increasing skeletal muscle mass. Rehabilitation therapy is recommended to enhance the return of severely ill COVID-19 patients to routine daily activity.

Skeletal muscle gene expression in older adults with type 2 diabetes mellitus undergoing calorie-restricted diet and recreational sports training - a randomized clinical trial.

AIMS: This study aimed to evaluate the impact of a 12-week calorie-restricted diet and recreational sports training on gene expressions IL-15, ATROGIN-1 and MURF-1 in skeletal muscle of T2D patients. METHODS: Older adults with T2D (n = 39, 60 ± 6.0 years, BMI 33.5 ± 0.6 kg/m2) were randomly allocated to Diet+Soccer (DS), Diet+Running (DR) or Diet (D). The training sessions were moderate-to-high-intensity and performed 3 × 40 min/week for 12-weeks. Gene expression from vastus lateralis muscle obtained by qRT-PCR, dual-energy X-ray and fasting blood testing measurements were performed before and after 12-weeks. Statistical analysis adopted were two-way ANOVA and Paired t-test for gene expression, and RM-ANOVA test for the remainder variables. RESULTS: Total body weight was reduced in ~4 kg representing body fat mass in all groups after 12-weeks (P < 0.05). HbA1c values decreased in all groups post-intervention. Lipids profile improved in the training groups (P < 0.05) after 12-weeks. ATROGIN-1 and MURF-1 mRNA reduced in the DS (1.084 ± 0.14 vs. 0.754 ± 1.14 and 1.175 ± 0.34 vs. 0.693 ± 0.12, respectively; P < 0.05), while IL-15 mRNA increased in the DR (1.056 ± 0.12 vs. 1.308 ± 0.13; P < 0.05) after 12-weeks intervention. CONCLUSION: Recreational training with a moderate calorie-restricted diet can downregulates the expression of atrophy-associated myokines and increases the expression of anti-inflammatory gene IL-15.

Non-thermal processing has an impact on the digestibility of the muscle proteins.

Muscle proteins undergo several processes before being ready in a final consumable form. All these processes affect the digestibility of muscle proteins and subsequent release of amino acids and peptides during digestion in the human gut. The present review examines the effects of different processing techniques, such as curing, drying, ripening, comminution, aging, and marination on the digestibility of muscle proteins. The review also examines how the source of muscle proteins alters the gastrointestinal protein digestion. Processing techniques affect the structural and functional properties of muscle proteins and can affect their digestibility negatively or positively depending on the processing conditions. Some of these techniques, such as aging and mincing, can induce favorable changes in muscle proteins, such as partial unfolding or exposure of cleavage sites, and increase susceptibility to hydrolysis by digestive enzymes whereas others, such as drying and marination, can induce unfavorable changes, such as severe cross-linking, protein aggregation, oxidation induced changes or increased disulfide (S-S) bond content, thereby decreasing proteolysis. The underlying mechanisms have been discussed in detail and the conclusions drawn in the light of existing knowledge provide information with potential industrial importance.

Prenatal diagnosis and genetic etiology analysis of a fetus with nemaline myopathy / 中华围产医学杂志

We reported a fetus with limb abnormalities and abnormal ultrasound soft markers diagnosed with nemaline myopathy. A pregnant woman (G1P0) underwent amniocentesis at 18 +2 gestational weeks due to thickened nuchal translucency suggested by ultrasound at 13 +5 gestational weeks. Karyotyping and single nucleotide polymorphism array of the amniotic fluid cells showed no fetal abnormalities. However, ultrasonographic reexaminations at 23, 28, and 28 +1 weeks indicated limb abnormalities and thickened nuchal fold, and the pregnant woman chose to terminate the pregnancy at 29 +2 gestational weeks. Whole exome sequencing showed compound heterozygous mutations of c.602G>A (p.W201*) and c.1516A>C (p.T506P) in the KLHL40 gene inherited from the mother and the father, respectively, resulting in nemaline myopathy type 8.

Thermal processing implications on the digestibility of meat, fish and seafood proteins.

Thermal processing is an inevitable part of the processing and preparation of meat and meat products for human consumption. However, thermal processing techniques, both commercial and domestic, induce modifications in muscle proteins which can have implications for their digestibility. The nutritive value of muscle proteins is closely related to their digestibility in the gastrointestinal tract and is determined by the end products that it presents in the assimilable form (amino acids and small peptides) for the absorption. The present review examines how different thermal processing techniques, such as sous-vide, microwave, stewing, roasting, boiling, frying, grilling, and steam cooking, affect the digestibility of muscle proteins in the gastrointestinal tract. By altering the functional and structural properties of muscle proteins, thermal processing has the potential to influence the digestibility negatively or positively, depending on the processing conditions. Thermal processes such as sous-vide can induce favourable changes, such as partial unfolding or exposure of cleavage sites, in muscle proteins and improve their digestibility whereas processes such as stewing and roasting can induce unfavourable changes, such as protein aggregation, severe oxidation, cross linking or increased disulfide (S-S) content and decrease the susceptibility of proteins during gastrointestinal digestion. The review examines how the underlying mechanisms of different processing conditions can be translated into higher or lower protein digestibility in detail. This review expands the current understanding of muscle protein digestion and generates knowledge that will be indispensable for optimizing the digestibility of thermally processed muscle foods for maximum nutritional benefits and optimal meal planning.

Six Weeks of Aerobic Exercise in Untrained Men With Overweight/Obesity Improved Training Adaptations, Performance and Body Composition Independent of Oat/Potato or Milk Based Protein-Carbohydrate Drink Supplementation.

Background: Protein availability around aerobic exercise might benefit aerobic capacity and body composition in normal weight adults. However, it is unknown if individuals with overweight/obesity elicit similar adaptations or improve other cardiometabolic/health-related markers in response to different types of protein. Thus, our aim was to study the effect of supplementation of two different protein drinks in conjunction with exercise on aerobic capacity, body composition and blood health markers in untrained subjects with overweight or obesity. Methods: The present study measured training adaptation and health parameters over a 6 week period in untrained men with overweight/obesity (n = 28; BMI 30.4 ± 2.2 kg/m2) ingesting either plant- (Oat/Potato; n = 8) or animal-based (Milk; n = 10) protein-carbohydrate drinks (10 g of protein/serving), or a control carbohydrate drink (n = 10) acutely before and after each training session (average three sessions/week @ 70% HRmax). Pre-post intervention V ˙ O 2 peak , muscle biopsies and blood samples were collected, body composition measured (DXA) and two different exercise tests performed. Body weight was controlled with participants remaining weight stable throughout the intervention. Results: For the groups combined, the training intervention significantly increased V ˙ O 2 peak (8%; P < 0.001), performance in a time-to-exhaustion trial (~ 100%; P < 0.001), mitochondrial protein content and enzyme activity (~20-200%). Lean body mass increased (1%; P < 0.01) and fat mass decreased (3%; P < 0.01). No significant effects on fasting blood glucose, insulin, lipids or markers of immune function were observed. There were no significant interactions between drink conditions for training adaptation or blood measurements. For body composition, the Oat/Potato and carbohydrate group decreased leg fat mass significantly more than the Milk group (interaction P < 0.05). Conclusions: Aerobic capacity and body composition were improved and a number of mitochondrial, glycolytic and oxidative skeletal muscle proteins and enzyme activities were upregulated by a 6 week training intervention. However, none of the parameters for endurance training adaptation were influenced by protein supplementation before and after each training session.

Myosin Binding Protein-C Forms Amyloid-Like Aggregates In Vitro.

This work investigated in vitro aggregation and amyloid properties of skeletal myosin binding protein-C (sMyBP-C) interacting in vivo with proteins of thick and thin filaments in the sarcomeric A-disc. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) found a rapid (5-10 min) formation of large (>2 µm) aggregates. sMyBP-C oligomers formed both at the initial 5-10 min and after 16 h of aggregation. Small angle X-ray scattering (SAXS) and DLS revealed sMyBP-C oligomers to consist of 7-10 monomers. TEM and atomic force microscopy (AFM) showed sMyBP-C to form amorphous aggregates (and, to a lesser degree, fibrillar structures) exhibiting no toxicity on cell culture. X-ray diffraction of sMyBP-C aggregates registered reflections attributed to a cross-ß quaternary structure. Circular dichroism (CD) showed the formation of the amyloid-like structure to occur without changes in the sMyBP-C secondary structure. The obtained results indicating a high in vitro aggregability of sMyBP-C are, apparently, a consequence of structural features of the domain organization of proteins of this family. Formation of pathological amyloid or amyloid-like sMyBP-C aggregates in vivo is little probable due to amino-acid sequence low identity (<26%), alternating ordered/disordered regions in the protein molecule, and S-S bonds providing for general stability.

Purification and identification of novel ACE inhibitory and ACE2 upregulating peptides from spent hen muscle proteins.

The study explored the use of spent hen, a major egg industry byproduct, as the starting material for preparing antihypertensive peptides. While previous studies were focused mainly on ACE inhibitory (ACEi) peptides, this work also studied peptides with ACE2 upregulating (ACE2u) activity, an emerging target for treating hypertension. Spent hen muscle protein hydrolysate prepared by thermoase (SPH-T) exhibited both ACEi and ACE2u activities. After ultrafiltration and chromatographic fractionation, five potent ACEi peptides, VRP, LKY, VRY, KYKA, and LKYKA, with IC50 values of 0.034-5.77 µg/mL, respectively, and four ACE2u peptides, VKW, VHPKESF, VVHPKESF and VAQWRTKYETDAIQRTEELEEAKKK, which increased ACE2 expression by 0.52-0.84 folds, respectively, were identified; VKW also showed ACEi activity. All peptides, except for VRP, are susceptible to degradation during the simulated gastrointestinal digestion. Our study supports the potential use of spent hens as antihypertensive functional food ingredients and nutraceuticals.

Protein supplementation increases adaptations to endurance training: A systematic review and meta-analysis.

BACKGROUND: Trials that assessed the impact of protein supplementation on endurance training adaptations have reported conflicting findings. OBJECTIVE: To determine the impact of protein supplementation during chronic endurance training on aerobic capacity, body composition and exercise performance in healthy and clinical populations. DESIGN: A systematic database search was conducted for randomised controlled trials addressing the effects of protein supplementation during endurance training on aerobic capacity, body composition and exercise performance in PubMed, Embase, Web of Science, and CINAHL. Meta-analyses were performed to outline the overall effects of protein supplementation with all studies containing endurance training components. The effects of endurance training and add-on effects of protein supplementation were evaluated by the meta-analyses with endurance training-focused studies. RESULTS: Nineteen studies and 1162 participants contributed to the analyses. Compared with the control group, the protein supplementation group demonstrated greater improvements in aerobic capacity measured by mixed peak oxygen uptake (V̇O2peak) and peak workload power (Wpeak) (standardised mean difference [SMD] = 0.36, 95% confidence interval [CI]: 0.05 to 0.67), and V̇O2peak (mean difference [MD] = 0.89 mL‧kg-1‧min-1, 95% CI: 0.07 to 1.70); had a greater lean mass gain (MD = 0.32 kg, 95% CI: 0.07 to 0.58); and had a greater improvement in time trial performance (MD = -29.1s, 95% CI:-55.3 to -3.0). Secondary analyses showed that, in addition to the substantial improvement in V̇O2peak (MD = 3.67 mL‧kg-1‧min-1, 95% CI: 2.32 to 5.03) attributed to endurance training, protein supplementation provided an additional 26.4% gain in V̇O2peak (MD = 0.97 mL‧kg-1‧min-1, 95% CI: -0.03 to 1.97). CONCLUSION: Protein supplementation further increased aerobic capacity, stimulated lean mass gain, and improved time trial performance during chronic endurance training in healthy and clinical populations. PROSPERO REGISTRATION NUMBER: (CRD42020155239).