Skeletal Muscle Tissue Samples Research Articles

Muscle Protein Synthesis in Response to Plant-Based Protein Isolates With and Without Added Leucine Versus Whey Protein in Young Men and Women

BackgroundPlant-based protein supplements often contain lower amounts of leucine and other essential amino acids (EAAs), potentially making them less effective in stimulating muscle protein synthesis (MPS) than animal-based proteins. Combining plant proteins could improve the EAA profile and more effectively support MPS. ObjectivesThe aim of this study was to determine the effect of a novel plant-based blend protein (PBP), PBP with added leucine (PBP + Leu) to levels equivalent to whey protein isolate (WHEY) on aminoacidemia and MPS responses in young men and women. We hypothesized that PBP + Leu would stimulate MPS equivalent to WHEY, and both would be greater than PBP. MethodsWe employed a randomized, double-blind, crossover study consisting of 3 separate study visits to compare PBP, PBP + Leu, and WHEY. To measure MPS response to ingestion of the supplements, a primed continuous infusion of L-[ring13C6] phenylalanine was administered for 8 h at each study visit. Skeletal muscle tissue and blood samples were collected to measure aminoacidemia and MPS. ResultsAll protein supplements increased mixed MPS above postabsorptive levels (P < 0.001). However, MPS increase following ingestion of PBP was less than that following ingestion of PBP + Leu (P = 0.002) and WHEY (P = 0.046). There were no differences in MPS between PBP + Leu and WHEY (P = 0.052). ConclusionsConsumption of PBP isolate with added leucine stimulated MPS to a similar extent as whey protein in young men and women. PBPs containing higher leucine content promote anabolism to a similar extent as animal-based proteins.This study was registered at clinicaltrials.gov as NCT05139160.

Determination of the time of death of a domestic cat by measuring the area of a wet spot

Animal cruelty is a criminal offence under the current legislation of Ukraine. When investigating criminal proceedings related to animal cruelty, including domestic cats, it is often necessary to establish the time of death. Therefore, the development of new methods for determining it and improving existing ones is extremely relevant. The purpose of the study was to establish the relationship between the obtained values of wet spot area indicators and the time of death. To achieve this goal, the authors propose a new method for determining the age of death of domestic cats based on the results of measuring the area of a wet spot obtained from skeletal muscle tissue samples of corpses (Shkundia method). To do this, samples of muscle tissue were taken from the corpses of cats, a wet spot preparation was obtained by pressing and its area was calculated to establish a correlation between the values of this indicator and the time that has passed since death. The study of the obtained indicators established that these values are constant, and the features of fluctuations in the values of this indicator with the time elapsed since the death of the animals were established and shown graphically. Using a number of statistical methods, the absence of dependence of wet spot area indicators on the muscles from which samples were taken for research and animal breeds was determined. The nature of changes in the values of the wet spot area indicator depending on time is established and the features of their fluctuations in different periods during 27 days from the moment of animal death were explained. Reference values of these indicators depending on the time elapsed since the death of animals are presented, which can be used by forensic veterinary experts in practical work to determine the time of the occurrence of death of domestic cats. Due to a number of advantages, this method can be widely implemented in the practice of forensic veterinary medicine

Maternal protein supplementation during mid-gestation improves offspring performance and metabolism in beef cows.

This study examined the impact of maternal protein supplementation during mid-gestation on offspring, considering potential sex-related effects. Forty-three pregnant purebred Tabapuã beef cows (20 female and 23 male fetuses) were collectively managed in a pasture until 100 d of gestation. From 100 to 200 d of gestation, they were randomly assigned to the restricted group [(RES) - basal diet (75% corn silage + 25% sugar cane bagasse + mineral mixture); n = 24] or control group [(CON) - same basal diet + based-plant supplement [40% of crude protein, 3.5g/kg of body weight (BW); n = 19]. From 200 d of gestation until parturition, all cows were equally fed corn silage and mineral mixture. During the cow-calf phase, cows and their calves were maintained in a pasture area. After weaning, calves were individually housed and evaluated during the backgrounding (255 to 320 d), growing 1 (321 to 381 d), and growing 2 (382 to 445 d) phases. Offspring's blood samples were collected at 210 and 445 d of age. Samples of skeletal muscle tissue were collected through biopsies at 7, 30, and 445 d of age. Muscle tissue samples were subjected to reverse-transcription quantitative polymerase chain reaction analysis. Prenatal treatment and offspring's sex (when pertinent) were considered fixed effects. The significance level was set at 5%. At mid-gestation, cows supplemented with protein reached 98% and 92% of their protein and energy requirements, while nonsupplemented cows attained only 30% and 50% of these requirements, respectively. The RES offspring were lighter at birth (27 vs. 31kg), weaning (197 vs. 214kg), and 445 d of age (398 vs. 429kg) (P ≤ 0.05). The CON calves had greater (P < 0.05) morphometric measurements overall. The CON offspring had ~26% greater muscle fiber area (P ≤ 0.01). There was a trend (P = 0.06) for a greater Mechanistic target of rapamycin kinase mRNA expression in the Longissimus thoracis in the CON group at 7 d of age. The Myogenic differentiation 1 expression was greater (P = 0.02) in RES-females. Upregulation of Carnitine palmitoyltransferase 2 was observed in RES offspring at 445 d (P = 0.04). Expression of Fatty acid binding protein 4 (P < 0.001), Peroxisome proliferator-activated receptor gamma (P < 0.001), and Stearoyl-Coenzyme A desaturase (P < 0.001) was upregulated in CON-females. Therefore, protein supplementation during gestation enhances offspring growth and promotes favorable responses to lipogenesis, particularly in females.

Can lifelong endurance exercise improve ageing through beneficial effects on circadian timing function, muscular performance and health status in men? Protocol for a comparative cross-sectional study.

A well-synchronized circadian system is a manifestation of an individual's health. A gradual weakening of the circadian timing function characterizes aging. Regular exercise has been suggested as a modality to improve many detrimental changes associated with aging. Therefore, we aim to examine the benefits and risks of lifelong endurance exercise on age-dependent changes in the circadian time-keeping function, the performance of the muscular system and health status. The study protocol has a comparative cross-sectional design, including groups of senior (65 to 75 years old, n=16) and young (20-30 years old, n=16) endurance runners and triathletes. Age-matched groups of young and elderly sedentary men are included as controls. The circadian function is evaluated mainly by measurement of urinary 6-sulphatoxymelatonin, a metabolite of the hormone melatonin shown to participate in the modulation of sleep cycles. The 6-sulphatoxymelatonin will be assessed in urine samples collected upon awakening in the morning and in the late evening, as a marker of melatonin production. In addition, sleep/activity rhythms and sleep quality will be measured by wrist actigraphy. Performance of the muscular system will be assessed by examination of muscular strength and quantifying of gene expression in the skeletal muscle tissue samples. Health status and age-induced reduction in immune function are to be analysed via the balance of pro- and anti-inflammatory immune markers in the plasma and skeletal muscle, body composition, bone density and physical fitness.

PSVII-18 Applying the Marbling Window Concept to Enhance Intramuscular Fat Development in Beef Cattle

Abstract The increase in marbling deposition without increasing the overall fatness of the carcass is one of the most challenge goals in meat industry. Previous studies have suggested the nutritional interventions at the neonatal stages as a strategy to enhance the commitment of muscular mesenchymal stem cells to adipogenesis, which may contribute to enhance marbling deposition at the finishing phase. As such the objective of this study was designed the evaluate the impact nutrient supplementation during the pre-weaning stage of beef calves has on intramuscular adipogenic determination. Thirty-four female calves were assigned to two experimental treatments: Control (CON, n = 17), where calves received only a mineral mixture as a supplement; Supplemented (SUP, n = 17), where calves received an energy-protein supplement (0.5 kg·100 kg of BW-1·day-1; the same mineral mixture was used in the CON supplement). Calves were supplemented from 100 to 250 days of age. Once animals reached 250 days of age, skeletal muscle tissue samples were biopsied from the 10th and 11th rib and used for identification of mesenchymal stem cells and preadipocytes through immunofluorescence, mRNA and protein abundance of adipo-fibrogenic markers, and abundance of candidate miRNA controlling expression of adipogenic commitment. Data were analyzed considering the completely randomized design of the experiment. Heifers were randomized across paddocks, and paddocks were randomized across treatments. The PROC MIXED of SAS 9.2 was used for all analyses. The average daily gain (P = 0.08) and final body weight (P = 0.07) tended to be greater in SUP than CON calves. The number of fibro-adipogenic progenitor cells (P = 0.69) did not differ between treatments, while a greater number of intramuscular pre-adipocytes were observed in SUP than CON calves (P = 0.01). The expression of miRNA-4429 (P = 0.20) did not differ between treatments, while the expression of miRNA-129-5p (P = 0.09) and miRNA-129-2-3p (P = 0.05) tended to be greater in CON than SUP calves. Our findings demonstrate that energy-protein supplementation from 100 to 250 days of age is capable to enhance intramuscular adipogenesis in beef cattle. Moreover, our results suggest that regulation of adipogenic commitment occurs by post-transcriptional regulation through miR-129 family.

Quadratic versus linear models to estimate the mean scattering spacing as a function of temperature in ex-vivo tissue

Previous works have shown the feasibility of temperature estimation during ultrasonic therapy using pulse-echo diagnostic ultrasound. These methods are based on the measurement of thermally induced changes in backscattered RF echoes due to thermal expansion and changes in ultrasonic velocity. They assume a joint contribution of these two parameters and a linear dependence with temperature. In this work, the contributions of velocity changes and thermal expansion to the evolution of the mean scatterer spacing of ex vivo bovine skeletal muscle tissue samples were decoupled. This was achieved by employing an experimental setup which allows measuring the absolute velocity value, using the through-transmission technique in a direct transmission configuration. The mean-scatterer spacing was estimated from spectral analysis of the backscattered signals obtained in pulse-echo mode. We propose a quadratic model of the thermal expansion coefficient to fit the evolution of the mean-scatterer spacing with temperature. The temperature increase estimated by the linear model, in the range of 29.5–47 °C, presents a percentage error (mean square error) of 11 %, while for the quadratic model the error is 4.8 %.

Histopathological and immunohistochemical study to determine the effects of monosodium glutamate on skeletal muscle development in chickens

The aim of this report was to investigate the effects of MSG administration on embryonic skeletal muscle development in chickens, using histological, histopathological, and immunohistochemical methods. A total of 410 fertilized chicken eggs were used and were divided into five groups: negative control, vehicle control, low-dose group (0.12 mg/g egg MSG), medium-dose group (0.6 mg/g egg MSG), and high-dose group (1.2 mg/g egg MSG). At incubation days 15, 18, and 21, eggs from each group were opened and six live embryos were obtained. The embryos were sacrificed by decapitation, and skeletal muscle tissue samples (musculus fibularis longus and musculus sternocoracoideus pectoralis) were obtained. Sections were stained with hematoxylin-eosin. Moreover, caspase-3 reactivity was determined using the immunohistochemical method. As a result, muscle development was delayed in the MSG groups and the number of caspase-3-positive cells was higher (p &lt; 0.05) than in the controls. Histopathological examinations revealed degenerative and necrotic changes in the skeletal muscle. Muscle degeneration (edema, muscle fiber degeneration, Zenker’s necrosis, and mononuclear cell infiltrations) were observed in all groups, except for the control groups. It was concluded that MSG may have adversely affected the development of the skeletal muscle.

Rapid Freezing of Skeletal and Cardiac Muscles Using Isopentane Cooled with Liquid Nitrogen and Tragacanth Gum for Histological, Genetic, and Protein Expression Studies.

Histological and molecular genetic evaluation of skeletal and cardiac muscles is an indispensable part of understanding muscle biology and the pathology of muscle disorders. Proper processing of the muscle tissue is a prerequisite for optimal evaluation. However, the processing of skeletal muscle samples often comes with many challenges. One of the commonly used methods of frozen tissue preparation involves optimal cutting temperature compound (OCT compound) embedding. This method is considered optimal for the processing of most of the routinely studied tissue samples. However, the processing of skeletal muscle samples using this method is often unsuitable as it causes artifacts and low DNA, RNA, and protein yield and quality due to the slow freezing of skeletal muscle tissues that allows ice crystals to form. One of the most suitable methods for skeletal muscle tissue processing for histological, genetic, and molecular studies is rapid freezing of freshly collected tissue samples using isopentane cooled with liquid nitrogen and tragacanth gum, which provides distinct advantages in consuming less time, preserving the cell morphology, and helping higher nucleic acids and protein yields. This chapter describes a protocol for rapid freezing of freshly collected skeletal muscle tissues using isopentane pre-chilled with liquid nitrogen and tragacanth gum. Skeletal muscle tissue samples processed using this protocol can be used for histological and immunological staining investigations and studies requiring DNA, RNA, and proteins from these tissues.

A novel method for determining postmortem interval based on the metabolomics of multiple organs combined with ensemble learning techniques.

Determining postmortem interval (PMI) is one of the most challenging and essential endeavors in forensic science. Developments in PMI estimation can take advantage of machine learning techniques. Currently, applying an algorithm to obtain information on multiple organs and conducting joint analysis to accurately estimate PMI are still in the early stages. This study aimed to establish a multi-organ stacking model that estimates PMI by analyzing differential compounds of four organs in rats. In a total of 140 rats, skeletal muscle, liver, lung, and kidney tissue samples were collected at each time point after death. Ultra-performance liquid chromatography coupled with high-resolution mass spectrometry was used to determine the compound profiles of the samples. The original data were preprocessed using multivariate statistical analysis to determine discriminant compounds. In addition, three interrelated and increasingly complex patterns (single organ optimal model, single organ stacking model, multi-organ stacking model) were established to estimate PMI. The accuracy and generalized area under the receiver operating characteristic curve of the multi-organ stacking model were the highest at 93% and 0.96, respectively. Only 1 of the 14 external validation samples was misclassified by the multi-organ stacking model. The results demonstrate that the application of the multi-organ combination to the stacking algorithm is a potential forensic tool for the accurate estimation of PMI.

In vivo treatment with varespladib, a phospholipase A2 inhibitor, prevents the peripheral neurotoxicity and systemic disorders induced by Micrurus corallinus (coral snake) venom in rats

In this study, we investigated the action of varespladib (VPL) alone or in combination with a coral snake antivenom (CAV) on the local and systemic effects induced by Micrurus corallinus venom in rats. Adult male Wistar rats were exposed to venom (1.5 mg/kg – i.m.) and immediately treated with CAV (antivenom:venom ratio 1:1.5 ‘v/w’ – i.p.), VPL (0.5 mg/kg – i.p.), or both of these treatments. The animals were monitored for 120 min and then anesthetized to collect blood samples used for haematological and serum biochemical analysis; after euthanasia, skeletal muscle, renal and hepatic tissue samples were collected for histopathological analysis. M. corallinus venom caused local oedema without subcutaneous haemorrhage or apparent necrosis formation, although there was accentuated muscle morphological damage; none of the treatments prevented oedema formation but the combination of CAV and VPL reduced venom-induced myonecrosis. Venom caused neuromuscular paralysis and respiratory impairment in approximately 60 min following envenomation; CAV alone did not prevent the neurotoxic action, whereas VPL alone prevented neurotoxic symptoms developing as did the combination of CAV and VPL. Venom induced significant increase of serum CK and AST release, mostly due to local and systemic myotoxicity, which was partially prevented by the combination of CAV and VPL. The release of hepatotoxic serum biomarkers (LDH and ALP) induced by M. corallinus venom was not prevented by CAV and VPL when individually administered; their combination effectively prevented ALP release. The venom-induced nephrotoxicity (increase in serum creatinine concentration) was prevented by all the treatments. VPL alone or in combination with CAV significantly prevented the venom-induced lymphocytosis. In conclusion, VPL shows to be effective at preventing the neurotoxic, nephrotoxic, and inflammatory activities of M. corallinus venom. In addition, VPL acts synergistically with antivenom to prevent a number of systemic effects caused by M. corallinus venom.

Protective effects of 7-hydroxyethyl chrysin on rats with exercise-induced fatigue in hypobaric hypoxia environment

: To investigate the protective effect of 7-hydroxyethyl chrysin (7-HEC) on rats with exercise-induced fatigue in hypobaric hypoxic condition.Forty healthy male Wistar rats were randomly divided into four groups with 10 rats in each group: control group, model group, chrysin group and 7-HEC group. The rats in control group were raised at local altitude but other three groups were raised in a simulating altitude of for hypobaric hypoxia treatment. The chrysin group and 7-HEC group were given chrysin or 7-HEC by gavage for respectively; while the control group and model group were given the same amount of sterilized water. The weight-bearing swimming tests were performed 3 d later, and the weight-bearing swimming time was documented. After rats were sacrificed, the liver and skeletal muscle tissue samples were taken for pathological examination and determination of lactate, malondialdehyde (MDA), total superoxide dismutase (T-SOD) and glycogen levels. Blood urea nitrogen was also determined. Compared with the model group, weight-bearing swimming times were significantly prolonged in 7-HEC group [ vs. (4.04±1.30) min, <0.01]; pathological changes in liver and skeletal muscle tissue were attenuated; generation rate of blood urea nitrogen vs. 0.60) mmol·L·min, <0.05], lactate [liver: (0.14±0.05) vs. (0.10±0.03) mg·g·min, skeletal muscle: vs. (0.18±] and MDA [liver: (0.48) vs. (0.78±0.28) nmol·mg·min, skeletal muscle: (0.87±0.19) vs. (0.63±0.11) nmol·mg·min] were significantly reduced (all < 0.05); glycogen content [liver: (15.16±2.69) vs. skeletal muscle: (1.46±0.49) vs.0.48) mg/g] and T-SOD [liver: (1.87±0.01) vs. (2.68±0.12) U/mL, skeletal muscle: 0.42) vs. 0.96) U/mL] were significantly improved (all <0.05). 7-HEC has significant protective effect on the rats with exercise-induced fatigue in hypobaric hypoxia condition.

Comparative Study of Microwave Oven-Assisted Tissue Processing with Isopropanol and Mineral Oil Mixture and Propylene Glycol Methyl Ether on Morphological Quality of Tissue Sections

Background: &#x0D; Over several years, xylene has been traditionally utilised as the clearing agent of choice in tissue-processing due to effectiveness in rapidly clearing tissue, facilitating the paraffin infiltration process. However, xylene use adversely impacts the health of personnel with long term exposure due to toxicity. In order to overcome these effects and replace it with a safer alternative agent, the present study aims to compare quality of tissue sections processed using an isopropanol and mineral oil mixture and propylene glycol methyl ether (PGME) as xylene substitutes.&#x0D; &#x0D; Methods: &#x0D; Rat skeletal muscle tissue samples (n=20) were prepared for each processing protocol with xylene substitutes. Tissue specimens were processed according to the proposed microwave protocol. The clearing steps were performed using isopropanol and mineral oil mixture, and PGME, replacing xylene. From each paraffin-embedded block, one section of 4-5µm thickness tissue was obtained and conventionally-stained with Haematoxylin and Eosin (H&amp;E). The histological sections were microscopically assessed and scored by a pathologist. A qualitative analysis was performed with the results obtained.&#x0D; &#x0D; Results: &#x0D; The overall score obtained for xylene processed tissue was 100% with a score of 2 for all the 3 parameters assessed. However, the outcome for tissue processed with isopropanol and mineral oil mixture was 28.6% unsatisfactory, 28.6% satisfactory and 42.8% good. In PGME-treated tissues, 14.3% were unsatisfactory sections, 71.4% were satisfactory and 14.3% produced good quality sections. Overall, tissues processed using both substitutes exhibited sufficient staining quality in terms of the aforementioned parameters as compared to xylene-processed tissues, though significant difference in scores were observed.&#x0D; &#x0D; Conclusion:&#x0D; Despite several challenges faced in the study, isopropanol and mineral oil mixture and PGME can be suggested as alternative clearing agents to xylene, provided having access to a more sophisticated microwave oven with precise temperature control for complete tissue-processing.

Acute sleep loss alters circulating fibroblast growth factor 21 levels in humans: A randomised crossover trial.

The hormone fibroblast growth factor 21 (FGF21) modulates tissue metabolism and circulates at higher levels in metabolic conditions associated with chronic sleep-wake disruption, such as type 2 diabetes and obesity. In the present study, we investigated whether acute sleep loss impacts circulating levels of FGF21 and tissue-specific production, and response pathways linked to FGF21. A total of 15 healthy normal-weight young men participated in a randomised crossover study with two conditions, sleep loss versus an 8.5-hr sleep window. The evening before each intervention, fasting blood was collected. Fasting, post-intervention morning skeletal muscle and adipose tissue samples underwent quantitative polymerase chain reaction and DNA methylation analyses, and serum FGF21 levels were measured before and after an oral glucose tolerance test. Serum levels of FGF21 were higher after sleep loss compared with sleep, both under fasting conditions and following glucose intake (~27%-30%, p=0.023). Fasting circulating levels of fibroblast activation protein, a protein which can degrade circulating FGF21, were not altered by sleep loss, whereas DNA methylation in the FGF21 promoter region increased only in adipose tissue. However, even though specifically the muscle exhibited transcriptional changes indicating adverse alterations to redox and metabolic homeostasis, no tissue-based changes were observed in expression of FGF21, its receptors, or selected signalling targets, in response to sleep loss. In summary, we found that acute sleep loss resulted in increased circulating levels of FGF21 in healthy young men, which may occur independent of a tissue-based stress response in metabolic peripheral tissues. Further studies may decipher whether changes in FGF21 signalling after sleep loss modulate metabolic outcomes associated with sleep or circadian disruption.

Untargeted Metabolomic Characteristics of Skeletal Muscle Dysfunction in Rabbits Induced by a High Fat Diet.

Simple SummaryIn the present study, we performed an untargeted metabolomic analysis of skeletal muscle of rabbits and found that the skeletal muscle of rabbits fed a high-fat diet is rich in many metabolites, most of which are associated with type 2 diabetes and metabolic syndrome. In this paper, the mechanism of action of these metabolites in skeletal muscle and the metabolic pathways that interfere with the normal operation mechanism of the body are described and presented in the form of charts. Finally, we found that skeletal muscle-rich phospholipids, long-chain carnitine, histidine, carnosine, and tetrahydrocortisone may be potential markers for type 2 diabetes and metabolic syndrome, and may serve as potential therapeutic targets for related diseases in the future.Type 2 diabetes and metabolic syndrome caused by a high fat diet (HFD) have become public health problems worldwide. These diseases are characterized by the oxidation of skeletal muscle mitochondria and disruption of insulin resistance, but the mechanisms are not well understood. Therefore, this study aims to reveal how high-fat diet causes skeletal muscle metabolic disorders. In total, 16 weaned rabbits were randomly divided into two groups, one group was fed a standard normal diet (SND) and the other group was fed a high fat diet (HFD) for 5 weeks. At the end of the five-week experiment, skeletal muscle tissue samples were taken from each rabbit. Untargeted metabolomic analysis was performed using ultra-performance liquid chromatography combined with mass spectrometry (UHPLC-MS/MS). The results showed that high fat diet significantly altered the expression levels of phospholipids, LCACs, histidine, carnosine, and tetrahydrocorticosterone in skeletal muscle. Principal component analysis (PCA) and least squares discriminant analysis (PLS-DA) showed that, compared with the SND group, skeletal muscle metabolism in HFD group was significantly up-regulated. Among 43 skeletal muscle metabolites in the HFD group, phospholipids, LCACs, histidine, carnosine, and tetrahydrocorticosteroids were identified as biomarkers of skeletal muscle metabolic diseases, and may become potential physiological targets of related diseases in the future. Untargeted metabonomics analysis showed that high-fat diet altered the metabolism of phospholipids, carnitine, amino acids and steroids in skeletal muscle of rabbits. Notably, phospholipids, LCACs, histidine, carnopeptide, and tetrahydrocorticosteroids block the oxidative capacity of mitochondria and disrupt the oxidative capacity of glucose and the fatty acid-glucose cycle in rabbit skeletal muscle.

Influence of irisin on diet-induced metabolic syndrome in experimental rat model.

To evaluate the influence of irisin on the experimental paradigm of non-alcoholic fatty liver (NAFL) as a part of MetS cluster. Forty male albino rats were divided into four groups; normal control, standard diet+irisin, high carbohydrate and fat diet (HCHF), and HCHF+irisin. After the experimental period, levels of fasting blood sugar (FBS), insulin, lipid profile, kidney functions, salusin-alpha (Sal-α), adropin, and retinol-binding protein-4 (RBP-4) were evaluated. Peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1α) expression in skeletal muscle was evaluated by quantitative real-time PCR. Aorta, liver, pancreas, and skeletal muscle tissue samples were prepared for histopathological examination. Rats administrated HCHF showed elevated levels of FBS, lipid profile, kidney functions, RBP-4, and downregulation of PGC-1α expression along with a decline in levels of insulin, Sal-α, and adropin while administration of irisin significantly attenuated these levels. Irisin as based therapy could emerge as a new line of treatment against MetS and its related diseases.

Impact of increasing levels of fumonisin on performance, liver toxicity, and tissue histopathology of finishing beef steers.

To address the gaps in current scientific knowledge, the objective of the present study was to investigate the impact of fumonisin exposure on feedlot cattle intake and performance. Fifty steers were received (day 0; 361 ± 6.4 kg), housed individually and fed once daily at 0800 hours. All steers were transitioned to a dry-rolled corn-based finishing diet from days 0 to 21 and then were fed the control finishing diet until day 50. Treatment diets were formulated to achieve ≤5 (CON), 15 (15PPM), 30 (30PPM), 60 (60PPM), or 90 ppm (90PPM) of total dietary fumonisin. Steers were fed the fumonisin treatment diets from day 50 until harvest on day 160; individual animal body weights (BW) were measured on days 0, 50, 100, 150, 159, and 160. Liver, kidney, and skeletal muscle tissue samples were collected at harvest for histopathological analyses, and liver samples were further analyzed for sphinganine (SA) and sphingosine (SO) concentration. Animal performance, carcass data, and liver enzyme concentration were analyzed using a mixed model; categorical data were analyzed via nonparametric models. Contrasts were used to test for linear and quadratic responses. Throughout the study, there was no effect of treatment (P > 0.60), or a linear response (P > 0.16) from increasing fumonisin levels, on BW or dry matter intake (DMI). However, CON tended to have a lower average daily gain (ADG) than the fumonisin treatments during the fumonisin treatment period (P = 0.10), and there was a positive linear response (P = 0.02) of ADG to fumonisin during the treatment period. There were no treatment differences in hot carcass weight, dressing percentage, marbling score, ribeye area, or yield grade. There were no effects of treatment on either liver abscesses (P = 0.95) or telangiectasis (P = 0.13). We observed a treatment difference for SA and SA:SO (P < 0.01), as well as a quadratic response (P < 0.02); both SA and SA:SO increased as dietary fumonisin increased. There were no observed differences between treatments for histopathology scores of kidney (P = 0.16), liver (P = 0.25), or skeletal muscle (P = 0.59) tissue. No adverse effects were observed in steers fed increasing dietary levels of fumonisin for 110 d prior to harvest. While elevated liver amino alcohol concentration did occur, negative effects on growth and carcass characters were not observed.

Efeitos da atividade física na histomorfometria muscular esquelética de modelo tumoral murino de caquexia

INTRODUÇÃO: A caquexia associada ao câncer (CAC) é uma síndrome paraneoplásica que ocorre com indivíduos com câncer que é caracterizada pela diminuição gradual de tecidos muscular esquelética e de tecido adiposo, promovendo um quadro de consumação física do indivíduo. A ocorrência de CAC determina de forma significativa a uma pior qualidade de vida e de sobrevida de indivíduos com câncer. A CAC não pode ser revertida pelo amparo nutricional convencional. Tratamentos não-farmacológicos empregados para a CAC tem reportado a realização de atividade física para possibilitar adaptações neurais e de hipertrofia muscular em indivíduos com a síndrome. OBJETIVO: Verificar os efeitos da atividade física em ambiente enriquecido na histomorfometria da musculatura esquelética de camundongos C57BL/6 submetidos ao modelo tumoral murino de caquexia associada ao câncer (CAC) MÉTODOS: Foram utilizados 38 camundongos C57BL/6 fêmeas, distribuídos aleatoriamente nos grupos de estudo. Todos os animais foram submetidos ao modelo tumoral murino singênico de Melanoma Cutâneo (MTMSMC) com a inoculação subcutânea de células B16F10. Os grupos de estudo são animais do experimento diagnostico CRC (n = 12), animais sedentários (n = 11) e animais submetidos à prática de atividade física em ambiente enriquecido (n = 15). O seguimento do estudo ocorreu por um período de dez dias. Após esse momento, todos os animais foram sacrificados e amostras de tecido muscular esquelético do gastrocnêmio foram submetidas às análises histomorfométricas. RESULTADOS: Os resultados da análise inferencial do peso absoluto e relativo muscular esquelético não diferiram entre os grupos do estudo. Todas as comparações das variáveis apresentaram tamanho do efeito pequeno. A análise histomorfométrica muscular revelou que a área da fibra muscular não diferiu entre os grupos do estudo. Contudo, essa área muscular, apresentou tamanho do efeito pequeno. CONCLUSÃO: Os resultados apresentados mostraram que a realização de atividade física no ambiente enriquecido não influenciou na área da fibra do músculo do gastrocnêmio de camundongos C57BL/6 submetidos ao MTMSMC, associada à CAC.

PSXI-34 Supplementation of grazing Nellore beef heifers during mid-to-late gestation as a strategy to improve skeletal muscle development of the offspring

Abstract The aim of this study was to evaluate supplementation effects of grazing heifers during mid-to-late of gestation on skeletal muscle development and performance of the progeny until weaning. One hundred and eighty Nellore beef heifers confirmed pregnant (timed AI) to a single sire were allotted to a completely randomized design with 2 treatments. Ninety heifers were fed only mineral (control) and the other 90 were fed a protein supplement (44.5% CP, 0.15% BW) from 90 to 274 days of gestation. Cows were grazed on Urochloa brizantha cv. Marandu pastures (5% CP and 64% NDF). At calving, cow–calf pairs were commingled and grazed on the same pasture until weaning. At 30 days after birth, a biopsy was performed to obtain samples of skeletal muscle tissue (Semitendinosus) from calves to determine the number and size of muscle fibre. Least squares mean for all data were computed using PROC MIXED of SAS (SAS Inst. Inc., Cary, NC). Calves from heifers supplemented with protein had greater birth BW (P &amp;lt; 0.001), ADG (P = 0.0147) and BW at 155 d (P = 0.0016) compared with calves from heifers not supplemented. However, calf BW at weaning (P = 0.1508) and gain from birth to weaning (P = 0.1446) did not differ. On the other hand, calves born from dams supplemented with protein had greater muscle fibre number (P = 0.0262), larger diameter of the fiber (P &amp;lt; 0.001), and smaller diameter of the fiber (P &amp;lt; 0.001) compared with calves from heifers not supplemented, although did not differ for mean fiber diameter (P = 0.8079). Fiber volume, fiber perimeter, and volume/area ratio were also affected (P &amp;lt; 0.001) by prepartum supplementation, and were greater on calves whose dams were fed with protein. In conclusion, supplementation of pregnant Nellore heifers with protein during the dry season improves calf birth BW, and promotes hyperplasia and hypertrophy in the skeletal muscle of the offspring.

Protein supplementation elicits greater gains in maximal oxygen uptake capacity and stimulates lean mass accretion during prolonged endurance training: a double-blind randomized controlled trial

Endurance training induces numerous cardiovascular and skeletal muscle adaptations, thereby increasing maximal oxygen uptake capacity (VO2max). Whether protein supplementation enhances these adaptations remains unclear. The present study was designed to determine the impact of protein supplementation on changes in VO2max during prolonged endurance training. We used a double-blind randomized controlled trial with repeated measures among 44 recreationally active, young males. Subjects performed 3 endurance training sessions per week for 10 wk. Supplements were provided immediately after each exercise session and daily before sleep, providing either protein (PRO group; n=19; 21.5±0.4 y) or an isocaloric amount of carbohydrate as control (CON group; n=21; 22.5±0.5 y). The VO2max, simulated 10-km time trial performance, and body composition (dual-energy X-ray absorptiometry) were measured before and after 5 and 10 wk of endurance training. Fasting skeletal muscle tissue samples were taken before and after 5 and 10 wk to measure skeletal muscle oxidative capacity, and fasting blood samples were taken every 2 wk to measure hematological factors. VO2max increased to a greater extent in the PRO group than in the CON group after 5 wk (from 49.9±0.8 to 54.9±1.1 vs 50.8±0.9 to 53.0±1.1 mL · kg-1 · min-1; P<0.05) and 10 wk (from 49.9±0.8 to 55.4±0.9 vs 50.8±0.9 to 53.9±1.2 mL · kg-1 · min-1; P<0.05). Lean body mass increased in the PRO group whereas lean body mass in the CON group remained stable during the first 5 wk (1.5±0.2 vs 0.1±0.3 kg; P<0.05) and after 10 wk (1.5±0.3 vs 0.4±0.3 kg; P<0.05). Throughout the intervention, fat mass reduced significantly in the PRO group and there were no changes in the CON group after 5 wk (-0.6±0.2 vs -0.1±0.2 kg; P>0.05) and 10 wk (-1.2±0.4 vs -0.2±0.2 kg; P<0.05). Protein supplementation elicited greater gains in VO2max and stimulated lean mass accretion but did not improve skeletal muscle oxidative capacity and endurance performance during 10 wk of endurance training in healthy, young males. This trial was registered at clinicaltrials.gov as NCT03462381.

Skeletal-muscle-derived mesenchymal stem/stromal cells from patients with osteoarthritis show superior biological properties compared to bone-derived cells

Mesenchymal stem/stromal cells (MSCs) are being exploited for patient-derived stem-cell therapies. As the biological properties of MSCs derived from skeletal muscle of osteoarthritis patients are poorly understood, the aim of this study was to compare muscle MSCs with well-recognized bone and bone marrow-derived MSCs from these patients.Paired samples of skeletal muscle and trabecular bone tissue were obtained from 21 patients with osteoarthritis. Isolated cells were compared using ex vivo immunophenotyping and detailed in vitro analyses. These included the colony forming unit fibroblast assay, growth kinetics, senescence, multilineage potential, immunophenotyping, and MSC marker gene expression profiling.Freshly isolated MSCs from muscle showed improved viability over bone-derived MSCs, with similar mesenchymal fraction. Muscle-derived MSCs showed superior clonogenicity, higher growth rates, and lower doubling times. Muscle-derived MSCs also showed superior osteogenic and myogenic properties and a positive correlation between CD271 expression and adipogenesis. Senescence rate as well as adipogenic and chondrogenic potentials were similar.Skeletal muscle-derived MSCs of osteoarthritis patients have superior clonogenicity and growth kinetics compared to bone-derived MSCs, making them a good candidate for autologous stem-cell therapies. Moreover, the positive correlation between CD271 and adipogenesis suggest that CD271 expressing muscle MSCs might contribute to muscle steatosis observed in osteoarthritis.