Muscle Tissue Research Articles

A wideband model to evaluate the dielectric properties of biological tissues from magnetic resonance acquisitions

Objective. Aim of this work is to illustrate and experimentally validate a model to evaluate the dielectric properties of biological tissues on a wide frequency band using the magnetic resonance imaging (MRI) technique.Approach. The dielectric behaviour of biological tissues depends on frequency, according to the so-called relaxation mechanisms. The adopted model derives the dielectric properties of biological tissues in the frequency range 10 MHz-20 GHz considering the presence of two relaxation mechanisms whose parameters are determined from quantities derived from MRI acquisitions. In particular, the MRI derived quantities are the water content and the dielectric properties of the tissue under study at the frequency of the MR scanner.Main results.The model was first theoretically validated on muscle and fat using literature data in the frequency range 10 MHz-20 GHz. Results showed capabilities of reconstructing dielectric properties with errors within 16%. Then the model was applied to ex vivo muscle and liver tissues, comparing the MRI-derived properties with data measured by the open probe technique in the frequency range 10 MHz-3 GHz, showing promising results.Significance. The use of medical techniques based on the application of electromagnetic fields (EMFs) is significantly increasing. To provide safe and effective treatments, it is necessary to know how human tissues react to the applied EMF. Since this information is embedded in the dielectric properties of biological tissues, an accurate and precise dielectric characterization is needed. Biological tissues are heterogenous, and their characteristics depend on several factors. Consequently, it is necessary to characterize dielectric propertiesin vivofor each specific patient. While this aim cannot be reached with traditional measurement techniques, through the adopted model these properties can be reconstructedin vivoon a wide frequency band from non-invasive MRI acquisitions.

Predicting post-lung transplant survival in systemic sclerosis using CT-derived features from preoperative chest CT scans.

The current understanding of survival prediction of lung transplant (LTx) patients with systemic sclerosis (SSc) is limited. This study aims to identify novel image features from preoperative chest CT scans associated with post-LTx survival in SSc patients and integrate them into comprehensive prediction models. We conducted a retrospective study based on a cohort of SSc patients with demographic information, clinical data, and preoperative chest CT scans who underwent LTx between 2004 and 2020. This cohort consists of 102 patients (mean age, 50 years ± 10, 61% (62/102) females). Five CT-derived body composition features (bone, skeletal muscle, visceral, subcutaneous, and intramuscular adipose tissues) and three CT-derived cardiopulmonary features (heart, arteries, and veins) were automatically computed using 3-D convolutional neural networks. Cox regression was used to identify post-LTx survival factors, generate composite prediction models, and stratify patients based on mortality risk. Model performance was assessed using the area under the receiver operating characteristics curve (ROC-AUC). Muscle mass ratio, bone density, artery-vein volume ratio, muscle volume, and heart volume ratio computed from CT images were significantly associated with post-LTx survival. Models using only CT-derived features outperformed all state-of-the-art clinical models in predicting post-LTx survival. The addition of CT-derived features improved the performance of traditional models at 1-year, 3-year, and 5-year survival prediction with maximum AUC scores of 0.77 (0.67-0.86), 0.85 (0.77-0.93), and 0.90 (95% CI: 0.83-0.97), respectively. The integration of CT-derived features with demographic and clinical features can significantly improve t post-LTx survival prediction and identify high-risk SSc patients. Question What CT features can predict post-lung-transplant survival for SSc patients? Finding CT body composition features such as muscle mass, bone density, and cardiopulmonary volumes significantly predict survival. Clinical relevance Our individualized risk assessment tool can better guide clinicians in choosing and managing patients requiring lung transplant for systemic sclerosis.

Mercury exposure in ringed seals (Pusa hispida saimensis) in Lake Saimaa, Finland, and the placenta as a possible non-invasive biomonitoring tool.

The Saimaa ringed seal (Pusa hispida saimensis) is a subspecies of ringed seal, landlocked in Lake Saimaa, Finland. The small population of less than 500 seals is facing many human-induced threats, including chemical contaminants. Mercury, in particular, has previously been suggested to be one of the chemicals affecting the viability of this endangered population. We analysed mercury concentrations from placentas and lanugo pup tissues (blubber, brain, kidney, liver, and muscle) to determine current prenatal exposure levels. These pups were found dead in or near birth lairs and were less than 3months old. Additionally, we used threshold values available in the literature to estimate the potential mercury toxicity to the Saimaa ringed seal. We also determined selenium concentrations for its potential to alleviate the adverse effects of mercury. We further supplemented our study with brain samples collected from various seal age classes. These seals were found dead by either natural causes or by being caught in gillnets. The analysed chemicals were present in all tissues. For lanugo pups, mercury concentrations were the highest in the kidney and liver, whereas the highest selenium to mercury molar ratio was observed in placentas. The toxicity evaluation suggested that, in severe cases, mercury may cause adverse effects in lanugo and older pups. In these cases, the selenium concentrations were low and selenium to mercury ratio was below 1:1 threshold ratio and thus unlikely to provide adequate protection from the adverse effects of mercury. Furthermore, adverse effects are more likely to occur in adult seals, as mercury bioaccumulates, leading to higher concentrations in older individuals. Placental mercury concentrations correlated to those in the livers and muscle tissues of lanugo pups. This, together with the fact that placentas can be collected non-invasively and in good condition, provides a potential novel method for biomonitoring mercury exposure in Saimaa ringed seals.

Combination therapy of corylifol A and anamorelin attenuates cachexia by decreasing pro-inflammatory cytokines, inhibiting lipolysis and increasing food intake in a murine colon cancer model

PurposeIn our previous study, we found that corylifol A (CYA), an active component derived from Psoralea corylifolia L, exhibited ameliorating effects on cancer cachexia. Anamorelin (AML), a ghrelin receptor agonist, is the only approved drug for the clinical treatment of cancer cachexia. Here, we checked the combination of CYA and AML on muscle atrophy and fat lipolysis in cancer cachexia mice to explore the possible clinic therapeutic potency of the combination on cancer cachexia.MethodsC26 colon tumor-bearing mice, a well-established animal model of cancer cachexia, were used to evaluate the effects of combined therapy involving CYA and AML on cancer cachexia and compared with those of CYA or AML alone. Histological analysis was performed to assess the changes in gastrocnemius (GAS) muscle tissue and epididymal adipose tissue (eWAT) and the possible involved molecular pathways were explored using western blotting and ELISA.ResultsTreatments of CYA, AML, or CYA+AML all significantly ameliorated the body weight decrease, muscle atrophy as well as fat loss in the tumor-bearing mice. Notably, the ameliorating effects of CYA+AML on fat loss were more significant than CYA or AML alone. The eWAT weight of mice in healthy control, C26 model, C26 +CYA, C26 +AML or C26 +CYA +AML group was 0.48 ± 0.07, 0.21 ± 0.10, 0.26 ± 0.10, 0.37 ± 0.10 and 0.48 ± 0.18 g, respectively. CYA+AML could increase food intake, significantly decrease the serum levels of inflammatory cytokines (TNF-α and IL-6) and inhibit the activation (phosphorylation) of hormone-sensitive lipase (HSL) in the eWAT tissues of the C26 tumor-bearing mice. Treatment of CYA along could significantly decrease the serum TNF-α level of the C26 tumor-bearing mice. Treatment of AML alone could increase food intake but could not decrease the serum levels of inflammatory cytokines of the C26 tumor-bearing mice.ConclusionThese results suggested that the effects of CYA+AML include both the appetite-stimulating effects of AML and the anti-inflammatory effects of CYA. CYA+AML was better than CYA or AML alone in ameliorating cancer cachexia, especially fat loss, of C26 tumor-bearing mice and might be a novel and beneficial therapeutic option for cancer cachexia.

Fullerene C60 Decreases Inflammation, Oxidative Stress and Apoptosis Induced by 7,12-Dimethylbenz[a]Anthracene (DMBA) in Muscle Tissue Via Caspase-3 and NRF-2 Protein Signaling Pathway

Fullerene C60 Decreases Inflammation, Oxidative Stress and Apoptosis Induced by 7,12-Dimethylbenz[a]Anthracene (DMBA) in Muscle Tissue Via Caspase-3 and NRF-2 Protein Signaling Pathway

External validation of a deep learning model for automatic segmentation of skeletal muscle and adipose tissue on abdominal computed tomography images.

Body composition assessment using computed tomography (CT) images at the L3-level is increasingly applied in cancer research. Robust high-throughput automated segmentation is key to assess large patient cohorts and to support implementation of body composition analysis into routine clinical practice. We trained and externally validated a deep learning neural network (DLNN) to automatically segment L3-CT images. Expert-drawn segmentations of visceral and subcutaneous adipose tissue (VAT/SAT) and skeletal muscle (SM) of L3-CT-images of 3,187 patients undergoing abdominal surgery were used to train a DLNN. The external validation cohort was comprised of 2,535 patients with abdominal cancer. DLNN performance was evaluated with (geometric) Dice Similarity (DS) and Lin's Concordance Correlation Coefficient. There was a strong concordance between automatic and manual segmentations with median DS for SM, VAT, and SAT of 0.97 (interquartile range, IQR: 0.95-0.98), 0.98 (IQR: 0.95-0.98), and 0.95 (IQR: 0.92-0.97), respectively. Concordance correlations were excellent: SM 0.964 (0.959-0.968), VAT 0.998 (0.998-0.998), and SAT 0.992 (0.991-0.993). Bland-Altman metrics indicated only small and clinically insignificant systematic offsets; SM radiodensity: 0.23 hounsfield units (0.5%), SM: 1.26 cm2.m-2 (2.8%), VAT: -1.02 cm2.m-2 (1.7%), and SAT: 3.24 cm2.m-2 (4.6%). A robustly-performing and independently externally validated DLNN for automated body composition analysis was developed. CT-based body composition analysis is highly prognostic for long-term overall survival in oncology. This DLNN was succesfully trained and externally validated on several large patient cohorts and will therefore enable large scale population studies and implementation of body composition analysis into clinical practice.

Benefits of chest wall mobilization on respiratory efficiency and functional exercise capacity in people with severe chronic obstructive pulmonary disease (COPD): A randomized controlled trial.

Coexistence of chest wall hypomobility and lung hyperinflation compromises respiratory muscle function and respiratory efficiency in people with severe chronic obstructive pulmonary disease (COPD). This study aimed to investigate the effect of chest wall mobilization on functional exercise capacity, respiratory muscle activity and respiratory muscle tissue oxygen saturation for people with severe COPD. Thirty male adults (age: 75 ± 6) diagnosed with severe COPD completed a 6-week programme (twice/week) according to intervention randomization (chest wall mobilization group, CWMG, n = 15; control group, CG, n = 15). Both groups received standardized education and walking exercise, while CWMG also received chest wall and thoracic spine mobilization. Electromyography of the essential and accessory respiratory muscles and tissue oxygen saturation of the intercostal muscle (StO2, measured by near-infrared spectroscopy) during incremental cycle exercise test were measured and compared between the two groups at pre-programme, post-programme and 3-month follow-up. Patients in CWMG demonstrated a significant increase in exercise tolerance from <3 METS to 4-6 METS (p = 0.000) after intervention. A significant decrease in activity of scalene, sternocleidomastoids and intercostal muscle during exercise test (p < 0.01) was found in CWMG, as compared to CG. A significant decrease in StO2 (p < 0.05) and greater decline in the slope of oxygenation dissociation (p = 0.000) were seen in CWMG during exercise test. These positive results were maintained at 3-month follow-up in CWMG. Improvements in exercise tolerance, respiratory muscle efficiency and oxygenation extraction ability in CWMG suggest a potential clinical benefit of integrating chest wall and thoracic spine mobilization for rehabilitation of people with severe COPD.

Pre- and post-skeletal muscle biopsy quantitative magnetic resonance imaging reveals correlations with histopathological findings.

Quantitative muscle magnetic resonance imaging (MRI) is a promising non-invasive method in the diagnostic workup as well as follow-up of neuromuscular disorders. The aim of this study was to correlate quantitative MRI (qMRI) parameters to histopathological changes in skeletal muscle tissue and thus to verify the data from our pilot study. Twenty-six patients (eight females, 46.4 ± 15.1 years) were examined within 72 h before and within 24 h after a skeletal muscle biopsy using quantitative muscle MRI. Post-biopsy MRI was employed to pinpoint the exact localization of the biopsy. qMRI parameters including fat fraction, water T2 relaxation time and diffusion metrics including fractional anisotropy, mean diffusivity, axial diffusivity and radial diffusivity were extracted from the localization of the biopsy and correlated with histopathological findings. Additionally, three different segmentation masks were applied to the qMRI dataset, to evaluate whether the whole muscle represents the exact biopsy location. Fat fraction and water T2 relaxation time in qMRI correlated significantly with the fat fraction in the muscle biopsy and histopathological inflammatory markers. Fractional anisotropy correlated with the quantity of type 2 fibres, whilst mean diffusivity correlated with p62. No differences were found using different segmentation masks in qMRI. In this follow-up study, the results from our previous study were verified regarding the correlation of qMRI parameters with histopathological features in muscle biopsies, indicating that qMRI serves as a suitable non-invasive method in the follow-up of patients with neuromuscular disorders. If post-biopsy MRI is not available, whole muscle volume can be used for histopathological correlations.

Abstract B002: Tumor-secreted PTHrP facilitates pancreatic cancer cachexia by regulation of de novo lipogenesis pathway

Abstract Pancreatic cancer is associated with one of the highest and most severe forms of cancer- associated cachexia amongst solid tumors. In an effort to further our understanding of the molecular etiology of pancreatic cancer-associated cachexia, we have developed mouse models to study adipose tissue wasting during Pancreatic Ductal Adenocarcinoma (PDAC) progression. In these pursuits, we have identified a pro-cachectic factor, PTHrP, that is produced and secreted by PDAC tumor cells and directly signals to adipocytes to facilitate wasting. Genetic deletion and pharmacological inhibition of PTHrP significantly extended the survival of tumor-bearing animals and dramatically reduced cachectic phenotypes in these animals, manifesting as decreased adipose and muscle tissue wasting. Mechanistic studies have shown crosstalk between tumor-cell derived PTHrP and adipose tissue PTH1R that drives the cachectic phenotype. Finally, bulk RNA sequencing analysis in PTHrP-driven cachectic models point towards a role for reduced de novo lipogenesis and adipogenesis in cachectic adipose depots, suggesting potential rewiring of the metabolic profile of white adipose tissue in tumor-bearing mice with higher PTHrP expression. Citation Format: Nikita Bhalerao, Jessica Peura, Yamini Ogoti, Calvin Johnson, Qingbo Chen, Ekaterina Korobkina, Faith Keller, Maximillan Wengyn, Robert Norgard, Richard Kremmer, Emma Watson, Marcus Ruscetti, David Guertin, Jason R Pitarresi. Tumor-secreted PTHrP facilitates pancreatic cancer cachexia by regulation of de novo lipogenesis pathway [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr B002.

Orbital Adipose Tissue: The Optimal Control for Back-Table Fluorescence Imaging of Orbital Tumors

Control tissue is essential for ensuring the precision of semiquantitative analysis in back-table fluorescence imaging. However, there remains a lack of agreement on the appropriate selection of control tissues. To evaluate the back-table fluorescence imaging performance of different normal tissues and identify the optimal normal tissue, a cohort of 39 patients with orbital tumors were enrolled in the study. Prior to surgery, these patients received indocyanine green (ICG) and following resection, 43 normal control tissues (34 adipose tissues, 3 skin tissues, 3 periosteal tissues, and 3 muscle tissues) were examined using back-table fluorescence imaging. The skin tissue demonstrated significantly elevated fluorescence intensity in comparison to the diseased tissue, whereas the muscle tissue exhibited a broad range and standard deviation of fluorescence signal intensity. Conversely, the adipose and periosteum displayed weak fluorescence signals with a relatively consistent distribution. Additionally, no significant correlations were found between the signal-to-background ratio (SBR) of adipose tissue and patients’ ages, genders, weights, disease duration, tumor origins, dosing of administration of ICG infusion, and the time interval between ICG infusion and surgery. However, a positive correlation was observed between the SBR of adipose tissue and its size, with larger adipose tissues (&gt;1 cm) showing an average SBR 27% higher than smaller adipose tissues (≤1 cm). In conclusion, the findings of this study demonstrated that adipose tissue consistently exhibited homogeneous hypofluorescence during back-table fluorescence imaging, regardless of patient clinical variables or imaging parameters. The size of the adipose tissue was identified as the primary factor influencing its fluorescence imaging characteristics, supporting its utility as an ideal control tissue for back-table fluorescence imaging.

280 AntagomiR-22-3p Injection alters miRNA expression and muscle fiber type of intrauterine growth restricted lambs

Abstract microRNAs (miRNA) are small non-coding RNAs that modulate muscle satellite cell proliferation. Previous research identified miR-22-3p as differentially expressed during ovine muscle development and in vitro experiments showed that antagomir-22-3p treatment enhanced satellite cell proliferation. The objective of this study was to test in vivo vascular injection of antagomir-22-3p in lateral saphenous vein on miRNA and HDAC family mRNA expression in intrauterine growth restricted lambs. Pregnant ewes (n = 18) with twins were either fed at 100% of NRC (CON) or nutrient restricted (60% NRC; NR) from gestational d 85 to parturition. On d 12 of age, NR lambs (n = 8) were randomly selected and given a systemic injection of antagomir-22-3p in the lateral saphenous vein of the right leg (MIR-NR). CON lambs (n = 8) were also randomly selected and given a sham injection of PBS in the lateral saphenous vein of the right leg (SHAM-CON). Antagomir-22-3p was reconstituted in phosphate buffered saline (PBS). Injections were given for 3 consecutive days and lambs harvested 24 d later. Blood samples were collected from each lamb weekly to monitor miR-22-3p expression. Lambs were slaughtered 24 d after the first injection and muscle mass measured. Muscle samples were removed for miR-22-3p and mRNA expression of potential targets. Cell-free circulating RNA was isolated from blood samples and miR-22-3p expression examined over time. Cell-free circulating miR-22-3p expression was downregulated (P &amp;lt; 0.05) for MIR-NR compared with SHAM-CON on d 14 after injection. On d 21 after injection, miR-22-3p expression in plasma tended (P = 0.08) to be down-regulated in MIR-NR compared with SHAM-CON. Lamb body weight and muscle weights at harvest were similar between MIR-NR and SHAM-CON treatments. In heart and semimembranosus (SM) muscles, expression of miR-22-3p was down-regulated (P &amp;lt; 0.05) in MIR-NR compared with SHAM-CON. In the gastrocnemius and semitendinosus muscle, miR-22-3p expression was unchanged (P &amp;gt; 0.05). The number of type I and IIa muscle fibers were greater (P &amp;lt; 0.05) for MIR-NR than SHAM-CON. Muscle fiber area of Type I, IIa or IIx fibers did not differ (P &amp;gt; 0.05) by treatment. The number of type IIx fibers did not differ (P &amp;gt; 0.05) between treatments. MIR-NR treatment appears to shift muscle fibers towards more oxidative metabolism and down-regulate HDAC-1, 3, and 11 and SIRT6 in SM. The systemic injection of antagomir-22-3P down-regulated miR-22-3p expression in circulation and in muscle tissues, which altered expression of HDAC/SIRT genes involved in muscle fiber type conversion and hypertrophy.

Biochemical responses of crayfish exposed to imidacloprid: assessment of oxidative stress, osmoregulatory response and neurotoxicity

ABSTRACT Among the nicotinoid insecticides, imidacloprid (IMI) may affect non-target invertebrates like aquatic crustaceans by entering the aquatic environment through rainfall. Nevertheless, there are not sufficient studies on the toxicity mechanism of IMI in crayfish. Here, we investigated the effects of IMI on oxidative stress, osmoregulatory, and neurotoxicity biomarkers. The 96-hour lethal concentration value (96 h-LC50) of IMI was determined to be 0.932 mg AI L−1. Four concentrations of IMI (0.932, 0.466, 0.233 and 0.117 mg AI L−1) were applied to crayfish for 96 h. Na+/K+-ATPase, Mg2+-ATPase, Ca2+-ATPase, and total ATPase activities had almost significantly concentration-related inhibition in both gill and muscle tissues (p < 0.05). Compare with control in hepatopancreas, the activities of GST, SOD and GPx were increased, while the activities of AChE, CES and GR were decreased (p < 0.05). As non-enzymatic parameters, a statistically significant (p < 0.05) increase in MDA levels and a decrease in GSH levels were observed in the hepatopancreas compared to the control group, which was not related to the concentration. In conclusion, it can be said that the study's biomarkers are highly helpful and that commercially consumed crayfish are a significant non-target organism in the assessment of IMI toxicity.

Treatment of chronic ruptures and defects of the Achilles tendon

Achilles tendon ruptures that are older than 4-6weeks or developed over amore extended period are chronic. Two challenges characterize the treatment. First, defect zones over alength of several centimeters must frequently be bridged. Second, aprolonged loss of function of the muscles leads to an irreversible fatty degeneration of the tissue. So that even if the tendon is restored, significant functional deficits remain. If there are doubts about the ability of the calf muscles to regenerate, regardless of the size of the defect, tendon transfers are recommended to use the power of an additional muscle to support the plantar flexion of the ankle. Established concepts are the transposition of the flexor hallucis longus or the peroneus brevis muscle. If the muscle is intact, defects of up to 2 cm can be treated with adirect suture. Defects between 2and 5 cm can be bridged using aVY-plasty or aturndown flap. For larger defects, free tendon transplants can be considered. The technical alternative for larger defects is atendon transfer of the flexor hallucis longus or the peroneus brevis muscle. Besides bridging the defect, another advantage of tendon transfer is that vital muscle tissue is placed in the bed of the Achilles tendon. Both tendons are covered with muscle tissue over nearly the full length, which offers advantages, especially in patients with critical soft tissue or after infection. Follow-up treatment is analogous to an acute Achilles tendon rupture. However, permanent impairments are possible; 75-80% of athletes regain their original performance level.

Effect of Semaglutide on Physical Function, Body Composition, and Biomarkers of Aging in Older Adults With Overweight and Insulin Resistance: Protocol for an Open-Labeled Randomized Controlled Trial.

Older adults with type 2 diabetes mellitus (T2DM) or prediabetes are at increased risk of adverse changes in body composition, physical function, and aging-related biomarkers compared to those with normal glucose tolerance. Semaglutide is a glucagon-like peptide 1 receptor agonist that has been approved for T2DM and chronic weight management. Although semaglutide is effective for weight loss and T2DM management, its effects on lean body mass, physical function, and biomarkers of aging are understudied in older adults. This study aims to compare the effects of lifestyle counseling with and that without semaglutide on body composition, physical function, and biomarkers of aging in older adults. This is an open-label randomized controlled trial. A total of 20 adults (aged 65 years and older) with elevated BMI (27-40 kg/m2) and prediabetes or well-controlled T2DM (hemoglobin A1c 5.7%-7.5%) are recruited, stratified by sex, and randomized 1:1 to one of 2 groups (semaglutide plus lifestyle counseling vs lifestyle counseling alone) and followed up for 5 months. Those in the semaglutide group are titrated to 1 mg weekly, as tolerated, for 12 weeks. Lifestyle counseling is given by registered dietitians and based on the Diabetes Prevention Program Lifestyle Change Program. Our primary outcomes include changes in lean mass, physical function, and biomarkers of aging. Body composition is measured by dual-energy x-ray absorptiometry and includes total fat mass and lean mass. Physical function is measured by 6-minute walk distance, grip strength, and short physical performance battery. Biomarkers of aging are measured in blood, skeletal muscle, and abdominal adipose tissue to include C-reactive protein, interleukin-6, tumor necrosis factors α, and β galactosidase staining. The study was funded in December 2021 with a projected data collection period from spring 2023 through summer 2024. Despite the elevated risk of adverse changes in body composition, physical function, and biomarkers of aging among older adults with glucose intolerance and elevated adiposity, the benefits and risks of commonly prescribed antihyperglycemic or weight loss medications such as semaglutide are understudied. This study aims to fill this knowledge gap to inform clinicians about the potential for additional clinically meaningful, nonglycemic effects of semaglutide. ClinicalTrials.gov NCT05786521; https://clinicaltrials.gov/study/NCT05786521. DERR1-10.2196/62667.

281 Changes in satellite cell number in maternal and fetal muscle with 5-hydroxy tryptophan supplementation during late gestation

Abstract Toxic tall fescue contains ergot alkaloids, which induce vasoconstriction in livestock, leading to fescue toxicosis. This condition can impact muscle development due to altered blood flow. Supplementation with 5-HTP may counteract the vasoconstrictive effects of fescue alkaloids. We aimed to investigate the influence of 5-HTP supplementation on satellite cells, myoblast, and preadipocyte numbers in maternal and fetal muscle during late gestation in Suffolk ewes. We hypothesized that 5-HTP supplementation would mitigate the effects of fescue toxicosis on muscle cell populations, potentially promoting muscle development and regeneration in maternal and fetal tissues. Suffolk ewes (n = 75), naïve to toxic tall fescue, were blocked by body condition score and body weight into 10 groups for synchronization. Ewes were confirmed pregnant using transabdominal ultrasound, and lamb number was estimated at gestational day (gd) 60. Pregnant ewes carrying twins (n = 30) were randomly assigned to one of three treatments: 1) negative control (CON, n = 10), 2) toxic tall fescue seed containing 1.77 mg ewe-1ּ d-1 ergovaline/ergovalinine plus 5-HTP (2.5 mg/kg BW) supplement (5HTP, n = 10), or 3) positive control, fed toxic tall fescue seed containing 1.77 mg ewe-1ּ d-1 ergovaline/ergovalinine (E+, n = 10). Ewes were individually fed a total mixed ration from gd 78 to gd 85 of pregnancy and then TMR plus treatment (CON, E+ or 5HTP) from gd 86 to d 111. On gd 112, terminal necropsies were performed, and semimembranosus muscle (SM) from the ewe and fetus was removed. Weights were obtained, and then samples were digested using pronase (1.5mg/mL) to isolate preadipocyte (PP1), myoblasts (PP2) and satellite cell (PP3) fractions using a pre-plating technique. Cells were quantified using a Neubauer-hemocytometer and trypan blue to also assess cell viability and changes in cell number. Fetal SM had a greater (P &amp;lt; 0.05) number of pre-adipocytes, myoblasts, and satellite cells per gram of tissue digested in comparison with the ewes. Pre-adipocyte and myoblast number per gram of tissue digested did not differ (P &amp;gt; 0.05) by treatment. The 5HTP group had the greater (P &amp;lt; 0.05) number of satellite cells per gram of tissue digested in comparison with the CON group. Satellite cell numbers tended (P &amp;lt; 0.10) to be greater in the 5HTP group in comparison to the E+ group. Satellite cell numbers from CON and E+ treatment groups did not differ (P &amp;gt; 0.05). In conclusion, 5-HTP supplementation during late gestation in Suffolk ewes exposed to toxic tall fescue significantly increased satellite cell numbers in maternal and fetal muscle tissues. This suggests a potential mitigation of the impact of fescue toxicosis on muscle cell populations.

Effects of monensin and a blend of magnesium oxide on performance, feeding behavior, and rumen morphometrics of Zebu beef cattle fed high-starch diets

Abstract This study aimed to evaluate the effects of a blend of different sources of magnesium oxide associated or not with monensin, on productive, ruminal, and nutritional parameters of steers. Eighty-four Nellore steers with an initial body weight (BW) of 367.3 ± 37.9 kg were allocated to one of 28 pens, with three steers per pen. Each pen was considered an experimental unit, and using a completely randomized design with a 2 × 2 factorial arrangement, the following treatments were assigned to each pen: (1) Control (CON) – a basal diet without additive inclusion; (2) Magnesium oxide blend (MG) – basal diet plus a magnesium-based product (pHix-up®, Timab Magnesium, Dinard, France) provided at 0.50% of dry matter (DM); (3) Monensin (MON) – basal diet plus 25 mg/ kg of DM of sodium monensin (Rumensin, Elanco Animal Health, Greenfield, IN); and (4) MG association with MON – basal diet plus MG + MON, at the same doses of the individual treatments. The experimental period lasted 100 days. Blood samples were collected on days 0, 13, and 70 to determine D-lactate levels. Daily feed intake was recorded, and animal ingestive behavior was visually observed on days 66 and 67. On day 70, skeletal muscle tissue samples were obtained through biopsy for gene expression analysis. At the end of the experimental period, carcass ultrasonography was conducted. Subsequently, the steers were slaughtered, and rumen epithelium samples were collected for morphometric analysis. The use of monensin, of magnesium oxide blend, and their interactions, were treated as fixed effects, while the pens were considered as a random effect. Statistical differences were considered when P &amp;lt; 0.05. Steers fed MG-containing diets consumed approximately 0.6 kg more dry matter per day than those fed diets without this additive (P = 0.01; 11.3 vs. 11.9 kg/day). The inclusion of MG in the diet increased (P = 0.02) the average daily gain (ADG). There was a greater Longissimus muscle area (LMA) and LMA per 100 kg of body weight (BW) (P ≤ 0.03) for steers-fed diets with MG. Steers fed MON exhibited reduced mRNA expression of the Atrogin-1 and mTOR compared to steers fed MG + MON diets (MON × MG: P ≤ 0.04). Steers fed MON had 6.9% greater feed efficiency (P = 0.02). Papillae width was lesser for CON than other treatments (MON × MG: P = 0.02). In conclusion, the magnesium oxide blend improved performance and carcass traits in high-energy feedlot diets, while monensin enhanced feed efficiency, suggesting potential for their use as alternatives or complements in beef cattle nutrition.

Trace elements in liver and muscle tissues from wild waterfowls in Australia: Risk associated with human consumption in a global context

Trace elements in game meats remain a point of concern for both the public and policymakers alike due to the human health implications if levels present are above guideline limits. This study aimed to: (1) determine trace element concentrations (As, Cd, Hg, Pb Cr, Cu, Se, Zn) in edible portions (breast meat and liver) of the four most frequently hunted duck Anatidae species inhabiting wetlands in Victoria, Australia, to identify the risk to human health from consumption; (2) investigate landscape-scale variables that may influence the detected concentrations and; (3) review the studies available (n = 41) in duck liver and muscle tissues from the 1970s to 2024, to contextualise the detected concentrations found on a global scale. Our study shows that ducks in Victoria had trace element concentrations below tolerable daily intake (TDI) guidelines for human health with one exception: notably high Hg in a filter-feeding specialist, the Pink-eared duck (Malacorhynchus membranaceus). Yet, the only trace element concentrations that were influenced by proximity to populated centres, were As and Zn. Compared to international reports, Pb concentrations in livers and muscle of Victorian waterfowl were lower, however, Pink-eared ducks had higher Hg than other duck (Anas spp.) species. Review of the worldwide data indicate that Pb concentrations in liver tissues from all Anas species have declined from the 1970s to 2024. This is the first study to identify this trend at a global scale. International movements towards Pb-shot bans, along with phasing out of Pb in gasoline and paint are the most likely cause of declining concentrations in tissues of wild waterfowl. These findings strongly underscore the importance of legislative efforts to limit trace elements entering the environment.

Topological polymeric glucosyl nanoaggregates in scaffold enable high-density piscine muscle tissue

Upon the pressure of conventional land agriculture and marine environment facing the future of human beings, the emerging of alternative proteins represented by cultured meat is expected with a breakthrough of efficient, safe and sustainable production. However, the cell proliferation efficiency and final myofiber density in current animal-derived scaffolds are still limited. Here, we incorporated five plant-derived edible polymeric glucosyl nanoparticles (GNPs) into gelatin/alginate hydrogels to spontaneously form nanoaggregates where nanotopographies were observed inside. The nanoscale topological morphology significantly enhances the adhesion and proliferation efficiencies of piscine satellite cells (PSCs) in the tailored extracellular matrix of as-prepared scaffold. Physically, the presence of GNP-induced nanoaggregate increases the interaction between ITG-A1 (membrane protein of PSCs) and hydrogel microenvironment, which activates the focal adhesion-integrin-cytoskeleton mechanotransduction signaling to promote cell proliferation. With a controlled diameter of hydrogel filament, these inner topological GNP nanoaggregates can also improve the density, alignment and differentiation efficiency of PSCs. When cultured in vitro for 15 days, the cell density, size and orientation of muscle fibers in the GNP-stimulated cultured fish fillet are very similar to the total cell mass in native fish muscle tissue.

Insulin resistance, bone health, and fracture risk.

The dramatic increase in obesity and metabolic syndrome (MetS) over the last half-century has led to a worldwide epidemic of type 2 diabetes mellitus (T2DM) as well as in the incidence of insulin resistance (IR). IR is defined as an impaired biological response to insulin stimulation in target tissues and is primarily related to the liver, muscle, and adipose tissue. The most frequent underlying cause is central obesity, and it is known that excess abdominal adipose tissue secretes increased amounts of free fatty acids, which directly affects insulin signalling, reduces glucose uptake in muscle, and triggers excessive triglyceride synthesis and gluconeogenesis in the liver. When pancreatic β cells are unable to secrete the higher levels of insulin needed, T2DM, the main complication of IR, occurs. Although obesity is generally associated with increased bone mass, recent data challenge this view and highlight the multifaceted nature of the obesity-bone relationship. Patients with T2DM are at significant risk for well-known complications of diabetes, including retinopathy, nephropathy, macrovascular disease, and neuropathy, but it is clear that they are also at high risk for fragility fractures. Moreover, recent data provide strong evidence that IR may key role in the increased fracture risk observed in both obesity and T2DM. In this concise review article, the role of IR in increased risk of osteoporotic fractures in MetS, obesity, and T2DM is discussed and summarised, including consideration of the need for fracture risk assessment as a 'preventive measure', especially in patients with T2DM and chronic MetS with abdominal obesity. Personalised and targeted diagnostic and therapeutic approaches to prevent osteoporotic fractures in IR-related diseases are needed and could make significant contributions to health outcomes.

From Brain to Muscle: The Role of Muscle Tissue in Neurodegenerative Disorders

From Brain to Muscle: The Role of Muscle Tissue in Neurodegenerative Disorders