bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamic resistance training improves cardiovascular autonomic variability in male hypertensive rats
Authors: Araujo Amanda , Dias Danielle , Bernardes Nathalia , Conti Filipe , Allioni Gabriela , Irigoyen Maria Cláudia , De Angelis Kátia 
Published: November 2023

The dynamic resistance training (DRT) has been the focus of recent researches; however, few studies evaluated the effects of DRT on hemodynamics of hypertensive subjects. The objective of this study was to evaluate the effects of DRT on blood pressure (BP) and cardiovascular autonomic modulation in spontaneously hypertensive rats. Thus, we used 16 adult males SHR, divided into two groups (n = 8/group): sedentary (SM) and trained (TM). Maximal exercise testing was conducted before and after the training period. The DRT, in moderate intensity (40–60% of the maximal load), was performed in a ladder adapted for rats per 8 weeks. After this period, blood glucose and triglyceride were measured and catheter was inserted in the carotid artery for direct measurement of BP (WINDAQ, 2 KHz). BP and heart rate variability were evaluated in time and frequency domains. At the end of the protocol, there was an improvement in physical capacity in the TM group (TM: 737±39 vs. SM: 476±50 g). Moreover, there were no differences in the weight of left ventricle and soleus muscle; however, the TM group showed an increase in plantar muscle (0.26±0.01 g) when compared to SM group (0.20±0.02 g). There was no difference in heart rate (TM: 350±8 vs. SM: 366±10 bpm) and blood glucose (TM: 88±3 vs. SM: 85±2 mg/dl); however, TM group showed reduced blood triglycerides values (TM: 110±7 vs. SM: 133±4 mg/dl). DTR did not induced reduction in mean, systolic and diastolic BP (mean BP, TM: 186±4 vs. TS: 185±9 mmHg). Despite that, DRT improved cardiac vagal modulation demonstrated by the increase in SD‐IP (TM: 6.61±1.31 vs. SM: 3.68±0.32 ms) and RMSSD (TM: 3.95±0.30 vs. SM: 3.02±0.25 ms). A reduction in BP variance (TM: 33±3 vs. SM: 66±4 mmHg2) and vascular sympathetic modulation (LF‐BP, TM: 6±2 vs. SM: 12±1 mmHg2) were observed in trained group. Additionally, DRT induced an improvement on spontaneous baroreflex (TM: 0.39±0.04 vs. SM: 0.22±0.01 ms/mmHg). We conclude that moderate intensity DRT in male SHR unchanged resting BP, but induced improvement on cardiovascular autonomic variability. These results suggesting a positive role of this approach, associated with aerobic exercise training, on hypertension management.Support or Funding InformationFAPESP 2015/10329‐5, 2015/11223‐6, UNINOVE.
Dystrophin Insufficiency Increases Skeletal Muscle Damage
Authors: Hill Sydney , Lien Stuart , Spaulding Hannah , Nonneman Dan , Ross Jason W , Selsby Joshua T 
Published: November 2023

Dystrophinopathies are caused by a mutation in the dystrophin gene, which can result in dystrophin protein insufficiency (Becker muscular dystrophy) and more commonly a dystrophin protein deficiency (Duchenne muscular dystrophy). These diseases are frequently modeled by the mdx mouse or the Golden Retriever Muscular Dystrophy model. Albeit useful, these models are not optimal for translational research due to inherent limitations. The purpose of this research was to determine the extent to which skeletal muscle is damaged by dystrophin insufficiency in a spontaneously occurring pig muscular dystrophy model. We hypothesized that dystrophin insufficiency would result in progressive muscle injury to skeletal muscle. To test this hypothesis, diaphragm from male pigs affected by dystrophin insufficiency and healthy male littermates were harvested at 3 months and 12 months of age and frozen for subsequent histological analysis. Sections were stained with hematoxylin and eosin and 3–5 random images were taken of each section. Central nucleation, a marker of skeletal muscle degeneration/regeneration, was similar between groups at 3 months of age, however, at 12 months of age central nucleation was increased by 42% in affected pigs compared to healthy pigs. When considering changes over time central nucleation increased in healthy pigs by 5‐fold (3 mo – 1.5%; 12 mo – 8%; p<0.05) and by 8‐fold in affected pigs (3 mo – 1.8%; 12 mo – 14%; p<0.05). These data indicate that the porcine diaphragm undergoes an increasing rate of central nucleation with normal aging. Importantly, this rate is dramatically increased with dystrophin insufficiency suggestive of an elevated pathological degeneration and regeneration. Interestingly, extracellular nuclei, which are associated with immune cell infiltration, and total muscle cells per area changed as a function of time but were similar between healthy and affected pigs at both 3 and 12 months of age. These data suggest that dystrophin insufficiency in diaphragm muscle increased muscle damage, which is consistent with disease‐related injury.Support or Funding InformationSupported by NIH R21 NS079603
Growth Arrest Specific 6 Activates Akt and ERK in Cultured Skeletal Muscle
Authors: Olsen Esther K. , Doxey Stephen A. , Chow Joshua L.Y. , Duplisea Michael , Thomson David M. 
Published: November 2023

Growth arrest specific 6 (Gas6) is a signaling factor that is found in a variety of tissues and is thought to be involved in the regulation of cell proliferation through activation of AKT and/or ERK signaling pathways. Its effect on skeletal muscle cells is unknown. Therefore, to test if Gas6 activates AKT and ERK in skeletal muscle, we incubated C2C12 myoblasts and myotubes with 0 to 800 ng/ml of Gas6 for 15 minutes. The cells were lysed and AKT and ERK content and phosphorylation were measured by western blotting. We found that in myoblasts Gas6 significantly increased ERK, but not AKT phosphorylation at an optimal concentration of 100 ng/ml. In myotubes, Gas6 significantly increased AKT but not ERK phosphorylation, also at an optimal concentration of 100 ng/ml. Our findings indicate that Gas6 is able to regulate these pathways in skeletal muscle and/or skeletal muscle progenitor cells. This suggests that Gas6 may be useful in conditions where muscle growth and/or satellite cell proliferation are impaired such as diabetes and old age.Support or Funding InformationThis work was supported by a Brigham Young University Gerontology Program Grant.
A single bout of cryotherapy does not alter the transcriptome or metabolome of human skeletal muscle
Authors: Sarver Dylan C , Sugg Kristoffer B , Disser Nathaniel P , Enselman Elizabeth R Siblinsky , Mendias Christopher L 
Published: November 2023

Cryotherapy is a commonly used therapeutic modality for skeletal muscle injuries in musculoskeletal medicine. Despite the widespread use of this modality, there is little known about the biochemical effects of cryotherapy in human skeletal muscle tissue. The purpose of this study was to determine the effects of a clinically relevant dose of cryotherapy on the transcriptome and metabolome of muscle tissue, as well as the activation of various signaling proteins. Using a paired design, 8 healthy male subjects (mean age 24.7±4.5 years, mean BMI 22.2±1.6) received ice‐cup massage or sham cup massage over a 45 cm2 area on each thigh for 15 min. Two hours after application, bilateral biopsies were taken from the vastus lateralis at a depth of 2 cm in the center of the ice or sham area. Muscle biopsies from each leg were then subjected to microarray, LC/MS‐based metabolomics analysis, or Western blot. Differences between groups were tested using paired t‐tests (α=0.05). Intramuscular (IM) temperature 2 cm deep to the subcutaneous layer was predicted from regression equations of skin temperature. Prior to administration of cryotherapy, intramuscular (IM) temperature was predicted to be 35.0±0.5°C. At the end of the 15 min application, IM temperature was reduced to 25.2±1.4°C (P<0.001), and by two hours remained below baseline at 31.7±0.8°C (P<0.001). Microarray analysis revealed changes in some non‐coding RNAs, but no differences were found for protein coding genes. Further analysis by qPCR showed no significant differences in cold‐shock genes which have been reported to be induced in animal tissue exposed to extended cooling. Metabolomics analysis of over 60 metabolites involved in glycolysis, oxidative phosphorylation, and amino acid metabolism showed significant (p<0.05) decreases in the hexose sugars and hypoxanthine by 15% and 17%, respectively, in cooled skeletal muscle tissue compared to controls. No differences in other metabolites were detected. Western blot analysis of major proteins involved in protein synthesis (p‐Akt, p‐mTOR, p‐p70S6K) showed no differences between groups. In summary, a clinically relevant administration of cryotherapy does not seem to have a significant, acute impact on the transcriptome, metabolome, or protein synthesis pathways in otherwise healthy muscle tissue.Support or Funding InformationNIH grants F32‐AR067086 and U24‐DK097153
Study of Acute Kidney Injury in hyperandrogenemic female rats
Authors: Patil Chetan N , Dalmasso Carolina , Maranon Rodrigo O. , Yanes Cardozo Licy L. , Reckelhoff Jane F. 
Published: November 2023

Chronic hyperandrogenemia is hallmark of polycystic ovarian syndrome (PCOS), affecting ~10% of women of reproductive age. Compared to men, women are protected against ischemia‐ reperfusion (I/R) acute kidney injury (AKI), but the potential susceptibility of women that have elevated androgens, as women with PCOS, to develop I/R‐induced AKI is not clear. Other models of hyperandrogenemia in females in which I/R AKI was studied utilized levels of testosterone similar to males. Using an established female rat model of PCOS that has a 3 fold increase in DHT, such as women with PCOS and 10 fold lower than in males, we tested the hypothesis that chronic hyperandrogenemia increases the risk of I/R‐induced AKI compare to placebo controls. Female SD rats were implanted with dihydrotestosterone (DHT, 7.5mg/90d) or placebo pellets (n=11/grp) beginning at 6 wks of age; pellets were changed every 85 d. At 6–7 mos of age, rats (n=3–4/grp) were subjected to sham or renal I/R with bilateral clamping of renal vessels for 30 min at 37±0.5°C. Rats were placed in metabolism cages for 24hrs reperfusion. At 48–72hr post‐surgery rats were again put in metabolic cages for 24hr, and then euthanized for blood and tissue samples. I/R increased plasma creatinine (PCr) 24hr post reperfusion in placebo (2.58±0.34 vs 0.86±0.1 mg/dL, p<0.05) as well as DHT treated rats (4.53± 0.46 vs 0.9±0.06 mg/dL, P<0.001) compared to sham‐I/R group. As noted, PCr in DHT‐treated rats was significantly higher than in placebo rats (4.53± 0.46 vs 2.58±0.34 mg/dL, p<0.05). When DHT rats were pre‐treated with androgen receptor antagonist (Flutamide, 30mg/kg/day, s.c.) for three days prior to I/R, PCr levels 24hr post reperfusion were not different than DHT–treated I/R groups (4.75 0.52 vs 4.53± 0.46 mg/dL, p=ns). These data show that rat exposure to chronic hyperandrogenemia causes significantly greater renal injury in response to I/R AKI than in controls. This injury is independent of the androgen receptor suggesting other mechanisms may be contributing to the higher level of renal injury after I/R AKI in females with PCOS.Support or Funding InformationSupported by NIH R01HL66072, P01HL05971.
High Protein Diets Blunt Insulin‐Stimulated Akt Phosphorylation While Enhancing Fibroblast Growth Factor Receptor Phosphorylation in Rat Liver
Authors: Noble Nicole D , Pettit‐Mee Ryan J , Cunningham Rory P , Sharma Naveen 
Published: November 2023

The activation of the fibroblast growth factor (FGF) pathway in the liver has been demonstrated to regulate hepatic metabolism of lipids, cholesterol, and bile acids. Irregularities in liver metabolism can result in many different metabolic disorders, which can be treated with various dietary interventions. However, the impact of high protein diets on FGF signaling in the liver remains unclear. Therefore the purpose of this study was to investigate the effect of a high casein‐based or a high soy‐based protein diet on signaling proteins associated with the FGF pathway within hepatic tissue. For 15 weeks, Sprague‐Dawley rats were fed either a control diet (CON; consisting of 20% casein protein by calories), a high casein protein diet (CAS; 40% casein protein), or a high soy protein diet (SOY; 40% soy protein). A terminal surgery was performed after an overnight fast. Under isoflurane anesthesia, saline or insulin (10U/kg) IP injections were administered to the rodents, then after 5 minutes, blood and liver samples were collected. Plasma levels of insulin and FGF‐21 were determined by ELISA. Tissue levels of FGF‐21, phosphorylated FGF receptor (pFGFR1Tyr654), and phosphorylated Akt (pAktSer473) were determined by Western immunoblot. A two‐way ANOVA was used to determine main effects of diet and insulin on plasma and tissue analytes. As expected, insulin injection resulted in a significant (P<0.05) increase in plasma insulin levels and increased pAktSer473 in the liver tissue compared to saline‐injected samples. Additionally the insulin‐induced elevation of pAktSer473 in the liver was blunted in the CAS and SOY groups compared to the CON group. There was a main effect of insulin for pFGFR1Tyr654 in the liver (insulin > saline; P<0.05). There was a main effect of diet for FGF‐21 in the liver (CAS < CON and SOY; P<0.05) while conversely plasma levels of FGF‐21 were significantly (P<0.05) elevated in plasma of the CAS group compared to either CON or SOY groups. Our findings reveal that high protein diets blunt the insulin‐enhanced pAktSer473. We speculate that high protein diets may enhance insulin‐stimulated FGF signaling in the liver independent of Akt‐mediated pathways. The therapeutic implication of this observation is yet to be determined.Support or Funding InformationCentral Michigan University Herbert H. and Grace A. Dow College of Health Professions, and the Office of Research and Graduate Studies Early Career Grant.
Stereological Analysis Of Long‐Term Effect Of Very High Fat Diet To Study The Synergism In Hormonal And Cellular Changes In Male Mice
Authors: Chakraborty Tandra Roy , Gomez Victoria , Babu Sathyapriya , Gurung Devya , Caraballo Trevor , Chakraborty Sanjoy 
Published: November 2023

ObjectiveTo determine the hormonal changes that occur as a result of the long term intake of a very high fat diet (VHFD) leads to simultaneous changes in the islets of Langerhans and adipocyte cell size.MethodsMale mice were fed with a normal chow diet (ND, n=15) and a VHFD (n=30) for 2, 12 and 24 weeks. Body weight, food intake, caloric intake [fat (saturated and unsaturated), protein and carbohydrate], hormone levels (leptin and insulin), and islet of Langerhans/adipocyte size were quantitatively recorded using stereology.ResultsIn VHFD‐fed animals, body weight showed significant percent increase within the first 12 weeks and then plateaued with time. VHFD‐fed animals consumed significantly less food than ND at all time periods indicating that it was the quality of food and not the quantity that caused this increase in body weight. Stereological analysis of male mice on VHFD showed significant increase in leptin and insulin levels along with accompanying growth in islet and adipocyte size within the first 12 weeks which plateaued as the mice aged. The increases in the islet and adipocyte size in VHFD fed animals were similar to the analogous increases in hormonal levels (2 vs 12 vs 24 weeks). These results, therefore, suggest that in diet‐ induced obesity changes, shifts in hormonal levels works hand in hand with metabolic adjustments at the cellular level to combat the effect of fat.ConclusionThus, hormonal resistance, changes in adiposity, islet size and caloric intake with prolonged exposure to high fat are probably defensive mechanisms employed to protect against diabetes. In order to understand these complicated and nuanced effects of high fat and to comprehend the underlying mechanism, it is important to focus on long‐term studies that emphasize the synergy between cellular and hormonal changes in addition to an analysis of individual components.
Effects of a TRPV4 Antagonist on Hydrocephalus in Wpk Rat Model
Authors: Danko Caleb , Preston Daniel , Simpson Stefanie , Blazer‐Yost Bonnie 
Published: November 2023

Hydrocephalus is a disease classified by an excess of Cerebrospinal Fluid (CSF) in the brain resulting from a variety of causes. Current treatments for hydrocephalus are limited to invasive surgical procedures that have high risks of failure or infection. The Choroid Plexus (CP) is responsible for production of the CSF, and is found in the lateral, third, and fourth ventricles of the brain. The CP contains a high resistance epithelium that tightly regulates the ionic and water movement during the production of CSF. The Wpk rat model has a single point mutation that induces a ciliopathy in homozygous recessive allele expression leading to hydrocephalus and polycystic kidney disease. The hydrocephalus in the Wpk rat model is a homologue to pediatric hydrocephalus that mimics a rapid progression of the disease, resulting in death of the rats, without intervention, within the first 21 days of life. Considering the tight control of fluid/electrolyte regulation in the CP, we have explored an osmotic‐ and mechano‐sensitive Ca2+ influx channel the transient receptor potential vanilloid‐4 (TRPV4), as a potential target for pharmaceutical regulation of CSF production. The Wpk rat pups are given a daily, intraperitoneal injection of the TRPV4 antagonist, RN1734 starting on day 7 after birth (P7), continuing through day 14 (P14), with untreated animals receiving a vehicle injection. Body weight is recorded daily with injections calculated for controlled drug doses according to body weight. Wpk rats were humanely euthanized on P15 with measurements taken of the body weight, kidney weight, cranial dimensions, and brain weight. These data were expressed in several parameters to account for the differences in body weight between the hydrocephalic and wild type pups as well as to account for the increase in cystic kidney weight in homozygous animals. Drug treatment had no effect on body weight, head dimensions or behavior of the wild‐type animals. However, in the hydrocephalic animals, head size in both the vertical and horizontal dimension were statistically decreased by antagonist treatment. These relationships were valid even when body weight or anephric body weights were taken into consideration. Likewise the brain weights were statistically lowered by treatment in the hydrocephalic animals. In this genetic model of hydrocephalus, treatment with a TRPV4 antagonist substantially ameliorates the hydrocephalic development suggesting that this class of drugs might be a good target for pharmaceutical development.Support or Funding InformationFunding: Hydrocephalus Association Innovator Award; Indiana University Collaborative Research Grant and Indiana Clinical and Translational Sciences Institute CTR Award.
Influence of Intrathoracic Vagotomy On the Cough Reflex in the Anesthetized Cat
Authors: Bolser Donald C , Shen Tabitha Y , Rose Melanie J , Musselwhite M Nicholas , Davenport Paul W 
Published: November 2023

Cervical vagotomy sections both lower airway and recurrent laryngeal afferent fibers and eliminates cough induced by stimulation of sensory afferents in the lower trachea and intrathoracic airways. In the guinea pig, recurrent laryngeal afferent fibers are primarily responsible for cough in response to mechanical or chemical stimulation of the upper trachea and larynx. Further, it has been proposed that lower airway slowly adapting receptors have a permissive effect on the cough reflex. The objective of this study was to determine the role of lower airway vagal afferent fibers on the cough reflex in the cat. We hypothesized that cough induced by mechanical or chemical stimuli applied to the lower airways or the larynx of this species would be depressed after vagotomy below the branch of the recurrent laryngeal nerve. Experiments were conducted in four anesthetized, bilaterally thoracotomized, and artificially ventilated cats. Artificial ventilation was accomplished via a tracheal cannula placed through an incision in the tenth trachea ring. Mechanical (via a flexible cannula through a small port in the trachea tube) or chemical (capsaicin, 0.5 cc, 10 μM) stimulation of the intrathoracic airway was employed during mechanical ventilation. Thoracic vagotomy virtually eliminated the cough response to mechanical stimulation of the lower airways (control cough number 4.7±1.7; after vagotomy 0.2±0.2 coughs, P<0.04). The cough response to mechanical stimulation of the larynx was also depressed after thoracic vagotomy. Capsaicin introduced into the intrathoracic trachea only elicited cough in two animals but this response was eliminated in both animals by thoracic vagotomy. The results support an important role of lower airway sensory feedback in the production of cough in the anesthetized cat. Further, in the presence of intact recurrent laryngeal nerves, the excitability of cough induced from the larynx is strongly influenced by sensory feedback from the lower airways.Support or Funding InformationNIH 1OT20D001983
Epigenetic modifications influence TLR3 expression and activity
Authors: McKernan Declan Patrick , Hennessy Conor 
Published: November 2023

BackgroundToll‐like receptors (TLRs) are a family of pattern recognition receptors (PRRs) which recognise conserved pathogen associated molecular patterns (PAMPs) present in bacteria and viruses e.g. TLR3 recognises dsRNA from viruses. TLRs are expressed on a variety of cells including intestinal epithelial cells and play an important role in the immune response by stimulating cytokine release via phosphorylation of signalling proteins, but it is not known how their expression is regulated. We hypothesised that epigenetic mechanisms such as DNA methylation and histone deacetylation may play a role. In order to investigate this, we studied the effect of inhibition and/or genetic knockout of the enzymes responsible for these events (DNA methyltransferases (DNMT) or histone deacetylase complexes (HDAC)) on TLR3 expression and signalling in HCT‐116 intestinal epithelial cells.MethodsHCT‐116 (both wild‐type (WT) and DNMT 1/3B double knockout (DKO) cells) cells were either untreated or treated with the pan‐HDAC inhibitor suberanilohydroxamic acid (SAHA, 10μM, 48hrs), or the DNMT inhibitor 5‐aza‐2‐deoxycytidine (500nM, 72hrs), followed by stimulation with the TLR3 ligand Poly I:C (10μg/ml, 6 or 24 hrs). Cytokine mRNA expression was measured using quantitative polymerase chain reaction (QPCR) while protein release was measured using ELISA of the cell culture supernatant. Intracellular signalling protein phosphorylation was measured using Western blotting. Statistical analyses was performed in SPSS and in all cases n ≥ 3.ResultsTreatment of HCT‐116 WT cells with Poly I:C resulted in a significant increase in TLR3 expression (p<0.001) and in the mRNA expression of cytokines (p<0.001) and also the release of cytokines (p<0.001). Poly I:C treatment also resulted in increased phosphorylation of signalling proteins (NF‐κB, IκBα, JNK, p38, IRF3). Pre‐treatment with SAHA, 5‐aza‐2‐deoxycytidine and genetic knockout of DNTM1/3b prevented this Poly I:C induced increase in TLR3 expression and cytokine mRNA expression, cytokine release and signalling protein phosphorylation.ConclusionInhibition of HDACs or DNMTs by pharmacological means or genetic knockout prevents TLR3 signalling and the activation of the TLR3 inflammatory pathway. This suggests that viral induced inflammation may be controlled using epigenetic modifying drugs.Support or Funding InformationCollege of Science Scholarship, NUI Galway