bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differences in Gastrocnemius mRNA Expression in Sedentary and Chronically Resistance Trained Rats Fed a Standard Chow Diet, or a Low‐Carbohydrate Diet, or a Western Diet
Authors: Hyatt Hayden W , Mobley C. Brooks , Kephart Wesley C , Holland A. Maleah , Mumford Petey , Lowery Ryan P , Roberts Michael D , Wilson Jacob M , Kavazis Andreas N 
Published: November 2023

Low‐carbohydrate diets (LCD) can facilitate weight loss, but their effects on skeletal muscle remain equivocal. In this experiment we investigated the effects of three diets on skeletal muscle gene expression in sedentary and resistance exercised rats. Male Sprague‐Dawley rats (9–10 weeks of age, 300–325 g) were divided into three groups: fed a standard chow diet (SCD) (30 g/day, 3.1 kcal/g, 58.0% CHO, 18.0%, fat 24.0% protein); fed a LCD (17 g/day, 5.2 kcal/g, 20.2% protein, 10.3% CHO, 69.5% fat); or fed a Western diet (WD) (20 g/day, 4.5 kcal/g, 15.2% protein, 42.7% CHO, 42.0% fat), for 6 weeks. During these six weeks animals were either sedentary (SED) or voluntarily exercised using resistance‐loaded running wheels (EXE). At the end of the experimental protocol, the gastrocnemius muscle was harvested and used to compare the gene expression of key metabolic targets in the gastrocnemius. There was a significant interaction (p = 0.04) in carnitine palmitoyltransferase 1B (CPT1B) mRNA levels in the gastrocnemius. Specifically, SCD‐EXE showed a decline compared to SCD‐SED, whereas LCD‐EXE and WD‐EXE showed an increase compared to LCD‐SED and WD‐SED, respectively. Also, there was a trend (p = 0.05) for an interaction effect in peroxisome proliferator‐activated receptor gamma, coactivator 1‐alpha (PGC‐1α) mRNA and there was a trend (p = 0.08) for an activity effect in pyruvate dehydrogenase kinase, isozyme 4 (PDK4) mRNA in the gastrocnemius. There were no significant (p > 0.05) differences for phosphofructokinase (PFK), phosphoenolpyruvate carboxykinase (PEPCK), or glucose transporter type 4 (GLUT4) mRNA levels in the gastrocnemius. Our data indicate that the three diets tested affect the mRNA expression of metabolic genes in the gastrocnemius of sedentary and chronic resistance exercise rats. Future experiments should investigate if these changes translate to protein and/or activity level differences.Support or Funding InformationFunding for this project was provided by JMW.
Voluntary Exercise Attenuates Reactive Oxygen Species Mediated Endothelial Dysfunction in Rodents Fed a High Sodium Diet Independent of Blood Pressure
Authors: Guers John J. , Kasecky‐Lardner Lauren , Farquhar William B. , Edwards David G. , Lennon‐Edwards Shannon 
Published: November 2023

High sodium diets have been shown to cause endothelial dysfunction and diminish nitric oxide bioavailability independent of blood pressure (BP). This deleterious effect has been linked to increases in reactive oxygen species (ROS). Exercise is known for its beneficial effect on endothelial function. This may be due, in part, to a reduction in ROS production. The purpose of this study was to test the hypothesis that voluntary wheel running prevents the deleterious effect of high sodium on endothelial function by reducing ROS independent of BP. Eight week old male Sprague‐Dawley rats were placed on either a normal sodium (NS, 0.4%) or high sodium (HS, 4.0%) diet for 6 weeks. Diet groups were further subdivided into a sedentary (NS, HS) or exercise group (NS‐EX, HS‐EX), the latter were placed in a cage with 24‐hour access to a running wheel. BP was measured 3 times per week and did not change in any group. Blood and urine were collected at baseline and 6 weeks in order to assess serum and urinary sodium. Animals were sacrificed after 6 weeks and endothelium‐dependent relaxation (EDR) was assessed by dose response to acetylcholine (ACh), in the presence and absence of the superoxide scavenger tempol and the NADPH oxidase inhibitor apocynin (Apo) in femoral rings. Citrate synthase (CS) activity was measured in the soleus muscle. Serum and urinary sodium concentrations were elevated in HS groups relative to NS (p<0.05). CS activity was greater in both exercise groups indicating a training effect (p < 0.05). Femoral EDR was reduced in HS (n=11) compared to NS (n=10) rats as demonstrated by an attenuated maximal response (Emax: HS, 39.4% ± 4.8 vs. NS, 66.9% ± 3.9; p < 0.05). Emax was improved by tempol (HS+T, 65.9% ± 5.6; p <0.05) and Apo (HS+Apo, 62.9% ± 10.9; p <0.05) compared to HS alone. Total EDR as assessed by area under the curve (AUC) increased in HS animals with the addition of tempol but did not quite reach significance (AUC: HS, 63.8% ± 8.1 vs. HS+T, 89.6% ± 8.02; p=0.06). Exercise rescued Emax in the presence of a HS diet (HS‐EX (n=8), 76.8% ± 7.3 vs. HS, 39.4% ± 4.8; p<0.05) and AUC (AUC: HS‐EX, 127.1% ± 0.1 vs. HS, 63.8% ± 8.1; p <0.05). The addition of tempol and/or Apo had negative effects in general on EDR in the exercise groups. AUC was diminished in the HS‐EX group with the addition of tempol (p<0.05), while the administration of Apo decreased AUC in NS‐EX (n=10) (p < 0.05). Both tempol and apocynin decreased Emax significantly in NS‐EX animals. In conclusion, HS impairs EDR through NADPH oxidase meditated ROS. Voluntary wheel running restored EDR likely through a reduction in ROS. EDR was diminished in the exercising groups with the addition of antioxidants suggesting there may be a critical level of ROS needed for maintenance of normal vascular functioning.Support or Funding InformationACSM Foundation Research Grant
CARDIOVASCULAR ALTERATIONS IN THE ACUTE PHASE OF CHAGAS DISEASE IN SEDENTARY AND TRAINED MICE
Authors: Martins‐Pinge Marli Cardoso , Lucchetti Bruno Fernando Cruz , de Ataides Raquel Hiviny , Zanluqui Nagela Ghabdan , Lovo‐Martins Maria Izabel , Tatakihara Vera Lucia , Michelini Lisete Compagno , Pinge‐Filho Phileno 
Published: November 2023

Trypanosoma cruzi infection causes heart inflammation and fibrosis with changes in the architecture and functionality of the heart. The literature shows that physical activity (PA) of chronic moderate‐intensity acts as a factor of resistance against T. cruzi infection in animals. The parameters of mean arterial pressure, heart rate (HR) and nitric oxide (NO) accompanying the acute phase of infection in animals trained have not been clarified. We aimed to evaluate the cardiovascular parameters, production of NO in the heart and plasma, parasitaemia and mortality in trained mice infected with T. cruzi. This study was approved by our institutional ethic committee (process number: 28105.2014.72). The AF was performed on treadmill for nine weeks. Then, the mice were infected with 5×103 trypomastigotes of T. cruzi (Y strain) or PBS (control). On days 7, 14 and 20 after inoculation (dpi) cardiovascular parameters were evaluated by CODA platform. The parasitemia was performed using the method of Brenner and dosage of NO by the Griess method. Data were analyzed using analysis of variance two‐way ANOVA. We observed resting bradycardia (758bpm vs 703bpm) and a better performance in the performance test (2.2 vs 1.5 km / h) in trained animals (n = 27) compared with sedentary (n = 14). With 20 dpi we found a decrease in HR in infected sedentary animals (SI) (n = 10) compared to the infected trained (TI) (n = 10) (669 vs 765bpm, p<0.05). We observed a decreased production of NO in cardiac tissue in IT compared with IS (6,51 vs 20.73 NO2μM). We observed a decrease in parasitemia in IT compared to IS in the 15 dpi (2,03×106 vs 1,17×106 parasites / ml) and 17 dpi (3,37×106 vs 1,02×106 parasites / ml). IT animals showed increased survival compared to SI. Exercise training improves cardiovascular parameters during infection by T. cruzi, contributing to the increased survival of infected animals, and NO may participate in this process.Support or Funding InformationCAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior)
Effects of Ovarian Hormone Loss and Aerobic Fitness on Brown Adipose Tissue Immunometabolic Characteristics in Rats
Authors: Vieira‐Potter Victoria Jeanne , Park Young‐Min , Zidon Terese M. , Welly Rebecca J. 
Published: November 2023

Ovary‐intact female rodents are less susceptible to white adipose tissue (WAT) inflammation and insulin resistance (IR). Females also are known to have greater brown adipose tissue (BAT) activity and uncoupling protein (UCP)‐1 expression. Ovary removal (i.e., OVX) increases adiposity, WAT inflammation, and IR. We recently demonstrated that female rats selectively bred for high running capacity (i.e., high‐fit HCR), compared to those bred for low running capacity (i.e., low‐fit LCR), are protected against OVX‐associated weight gain and IR and have more BAT, which correlates strongly with their greater resting energy expenditure. The objectives of the present study were to determine: 1) how HCR and LCR rats differ in their interscapular BAT immunometabolic characteristics; and 2) how OVX affects BAT of HCR and LCR rats. HCR and LCR rats had OVX or SHM (i.e., sham ovariectomy) surgeries at 25 weeks of age and were followed for up to 27 weeks, during which time they remained sedentary and were fed standard rodent chow. Food intake, weight gain, adiposity (DXA and fat pad weights), circulating adipokines (ELISA), spontaneous cage physical activity (SPA) (metabolic cages with beam break quantification) and insulin sensitivity (hyperinsulinemic euglycemic clamps) were compared among the 4 groups via 2‐way ANOVA to determine main effects of line (i.e., HCR v. LCR), treatment (i.e., OVX v. SHM), and line × treatment interactions (which were followed by LSD multiple comparison tests, as appropriate); correlations are Pearson bivariate. Statistical analyses were performed using SPSS v21 and P<0.05 was considered significant. BAT was assessed via UCP‐1 immunostaining, gene (rtPCR) and protein (Western) expression, citrate synthase activity (enzyme assay), and insulin‐mediated glucose uptake under clamp conditions. While HCR and LCR rats did not differ in histological, gene, enzymatic, or protein indexes of non‐stimulated BAT activity, HCR had lower BAT inflammatory cytokine (e.g., TNF‐a) and T cell (e.g., CD3, CD4) gene expression (all P<0.05 compared to LCR) and markedly greater insulin‐stimulated glucose uptake into BAT (P<0.01 compared to LCR), which was strongly related to their improved systemic glucose infusion rate (r = 0.5, P=0.014). In both HCR and LCR rats, OVX reduced skeletal muscle insulin sensitivity (P<0.02) but did not affect insulin‐stimulated glucose uptake into WAT or BAT. Unexpectedly, in HCR and LCR rats, OVX increased BAT UCP‐1 and reduced several inflammatory genes (e.g., TNF‐a, CD3, CD4, CD8, all P<0.05). We hypothesize that UCP‐1 up‐regulation following OVX may be a compensatory defense mechanism against oxidative stress resulting from OVX.Support or Funding InformationMU Research Council Grant to VJ Vieira‐Potter
The Role of Body Habitus in Predicting Cardiorespiratory Fitness: Findings from the FRIEND Registry
Authors: Baynard Tracy , Arena Ross A , Myers Jonathon , Kaminsky Leonard A 
Published: November 2023

Body habitus has been previously reported to be important in the development of non‐exercise prediction models for estimating cardiorespiratory fitness (CRF). Yet, these previous models have included indices of physical activity, which is not widely assessed in the clinical setting.PurposeTo validate and cross‐validate a non‐exercise prediction model from a large and apparently healthy U.S. cohort of individuals who underwent an analysis of body habitus (waist circumference (WC) and body mass index (BMI)) with measured CRF.MethodsThe large cohort (5030 individuals) was split into validation (4030) and cross‐validation groups (1000), whereby waist circumference and maximal aerobic capacity (VO2max) were assessed by rigorously approved laboratories.ResultsVO2max was estimated in 2 multiple regression equations using age, sex, and either WC (r = 0.77; standard error of the estimate (SEE) 6.70 mLO2 ·kg−1·min−1) or BMI (r = 0.76; SEE 6.89 mLO2 ·kg−1·min−1). Cross‐validation yielded similar results. However, as VO2max increased, there was increased bias, suggesting VO2max may be underestimated at higher values.ConclusionsBoth WC and BMI prediction models yielded similar findings, with WC having a slightly smaller SEE. These measures of body habitus appear to be adequate in predicting CRF using non‐exercise parameters, even without a measure of physical activity. Caution should be taken when using these equations in higher fit individuals.Support or Funding InformationTKC Global Solutions, LLC.
The Effect of Endurance Exercise on Doxorubicin Cardiotoxicity and Antitumor Efficacy in Tumor‐Bearing Mice
Authors: Lien Chia‐Ying , Jensen Brock Thomas , Chen Mei‐Li , Wu Chung‐Hsin , Lin Ching‐Lung , Chuang Tai‐Yuan 
Published: November 2023

Doxorubicin (DOX) is a highly effective antineoplastic agent used in the treatment of various cancers. Conversely, DOX treatment can result in acute and chronic cardiotoxicity and may eventually lead to congestive heart failure and premature death. Many studies have reported that endurance exercise attenuates both acute and chronic DOX cardiotoxicity. However, the majority of studies used non‐tumor‐bearing animals. Therefore, it is of great interest to investigate the combined effects of exercise and DOX on the anti‐tumor efficacy of this commonly used chemotherapy.PurposeThe primary purpose of this study was to determine if endurance exercise can attenuate DOX cardiotoxicity and preserve the antineoplastic activities of DOX. Secondarily, if the antineoplastic efficacy was maintained with endurance exercise and DOX treatment, what mechanisms are responsible for cardioprotection.MethodsSix week old C57BL/6 mice were randomly assigned into one of following groups: Control (n=6), Tumor_SED_DOX (n=9), Tumor_ED_DOX (n=9), Tumor_EA_DOX (n=9). Excluding the control group, all animals were inoculated with melanoma cells (B16F10, 5 × 106) at 6 weeks of age and received an injection of DOX (6 mg/kg) at 8 weeks. Two days post inoculation, Tumor_ED_DOX started an endurance exercise protocol. Two days post DOX injections, Tumor_EA_DOX started an endurance exercise protocol. Control and Tumor_SED_DOX were limited to normal cage activity. Following exercise and DOX treatments, cardiac function was measured in vivo. Biochemical analyses were performed to determine inflammatory, apoptosis, and antioxidant responses to combined treatment.ResultsTumor size was not significantly different across groups (Tumor_SED_DOX, 865±207 mm3; Tumor_ED_DOX, 692±133 mm3; Tumor_EA_DOX, 621±148 mm3, P > 0.05). Fractional shortening and ejection fraction was significant lower in control mice compared to all experimental groups (P < 0.05). Additional functional measures were not significant across all groups (P > 0.05). Biochemical analyses revealed Tumor_SED_DOX had greater inflammatory (NF‐kB) and apoptosis (AkT, Bax / Bcl‐2, cyt‐c) responses and reduced antioxidant expression (SOD2) (P < 0.05).ConclusionsIn this investigation, tumor size was unadulterated by combined exercise and DOX treatment. Cardiac dysfunction was not observed in DOX treated animals. Specifically, control animals FS and EF were not different from DOX treated animals. This was likely due to a inadequate cumulative dose of DOX (250 mg/kg). Interestingly, Tumor_SED_DOX still demonstrated exacerbated inflammation, apoptosis and impaired antioxidant defense when compared to exercise trained animals. This suggests that endurance exercise may still have protective effects against DOX‐induced cardiotoxicity in a tumor bearing‐model.Support or Funding Information

Ministry of Science and Technology of Taiwan: under Grant 104‐2410‐H‐002 ‐182 –
Individual Differences in Components of the Pressor Responses to Isometric and Dynamic Handgrip Exercise in Humans
Authors: Watanabe Kazuhito , Ichinose Masashi , Tsuji Bun , Maeda Seiji , Nishiyasu Takeshi 
Published: November 2023

The aim of this study was to test the hypotheses that, in humans, cardiac output (CO) and total peripheral vascular resistance (TPR) responses to dynamic handgrip exercise vary among individuals as demonstrated recently with isometric handgrip exercise, and that the responses of the components mediating the pressor response have a similarity between those exercises in the same individuals. We studied 30 healthy male and female volunteers with a mean age of 25 ± 0.5 yr, body weight of 64 ± 2.4 kg, and height of 169 ± 1.5 cm (means ± SE). The subjects assumed a supine position and performed isometric and dynamic (30 contractions/min) handgrip exercise at 50% of maximal voluntary contraction until fatigue separately (84 ± 3 s and 178 ± 14 s, respectively). We assessed the magnitude of the variance in the individual changes in mean arterial pressure (MAP), CO and TPR at 20%, 40%, 60%, 80% and 100% of fatigue using inter individual coefficient of variation (CV). Although CVs for changes in CO and TPR between the rest and the exercise periods were not much different from the CV for change in MAP at 20% of fatigue, the CVs for changes in CO and TPR were 2‐ to 3‐fold greater than the CV for change in MAP at ≥40% of fatigue in both trials. Thus the components of the pressor responses to isometric as well as dynamic handgrip exercise varied widely among subjects at ≥40% of fatigue. In addition, the CO and TPR responses during dynamic handgrip exercise correlated positively with the corresponding responses during isometric handgrip exercise from 20% to 100% of fatigue (CO: r = 0.675–0.755, P < 0.01; TPR: r = 0.566–0.788, P < 0.01). Our findings demonstrate that the CO and TPR responses during moderate to exhaustive handgrip exercise (≥40% of fatigue) vary considerably among individuals compared to the pressor response irrespective of the exercise modality (isometric or dynamic). They also suggest that the CO and TPR responses to handgrip exercise is similar between the modalities in the same individuals throughout the course of exercise.Support or Funding InformationThis study was supported by the grants from Japan Society for the Promotion of Science.
Blocking Proteinase‐Activated Receptor‐2 Attenuates Amplified Pressor Response in Rats with Femoral Artery Occlusion
Authors: Lu Jian , Xing Jihong , Li Jianhua 
Published: November 2023

A rat model of femoral artery ligation was employed to study the exercise pressor reflex in peripheral artery disease (PAD). Our prior studies have shown a functional interaction in proteinase‐activated receptor‐2 (PAR2) and transient receptor potential channel A1 (TRPA1) in muscle sensory nerves and TRPA1 is engaged in the amplified sympathetic responsiveness observed in rats with femoral artery occlusion. The current study was to determine the role played by PAR2 in regulating amplified blood pressure response observed in rats following 72 hours of femoral artery occlusion. Dorsal root ganglion (DRG) tissues of control limbs and limbs with 72 hours of femoral occlusion were obtained to examine the protein levels of PAR2 using western blot analysis. Femoral occlusion significantly increased expression of PAR2 in DRG (optical density: 1.02±0.03 in control vs. 1.57±0.05 after occlusion, P<0.05; n = 5 in each group). In addition, we examined the pressor response to static muscle contraction after 2, 10 and 20μg/kg of FSLLRY‐NH2 (a PAR2 inhibitor) were injected into the arterial blood supply of the hindlimb muscle of control rats and occluded rats. We found that FSLLRY‐NH2 failed to attenuate the pressor response to contraction in control rats. However, 10 and 20μg/kg of FSLLRY‐NH2 significantly attenuated the pressor response to contraction in occluded rats. i.e., in control rats the peak response of mean arterial pressure (MAP) was 26±5 mmHg after saline (n=6) and 24±3 mmHg after 20μg/kg of FSLLRY‐NH2 (n=6; P > 0.05 vs. saline); in occluded rats the peak response of MAP was 35±6 mmHg after saline (n=5) and 21±4 mmHg after 20μg/kg of FSLLRY‐NH2 (n=6; P < 0.05 vs. saline). Note that there was no difference in developed muscle tension between saline and FSLLRY‐NH2 groups (555±10 vs. 550±15 g in control rats, P > 0.05; and 556±10g vs. 571±20g in occluded rats, P > 0.05). Overall, our data suggest that PAR2 in muscle sensory nerves likely contributes to the amplified sympathetic and pressor responsiveness observed in experimental PAD rats.Support or Funding InformationNIH P01 HL096570 and AHA Established Investigator Award 0840130N
Comparison of Food Availability in School Stores in Seoul, South Korea Before and After Implementation of Two National Food‐ and Nutrient‐Based Policies
Authors: Choi Seul Ki , Frongillo Edward A , Blake Christine E , Thrasher James F 
Published: November 2023

Public health interest in preventing childhood obesity and chronic diseases by improving school food environments has been growing around the world. As part of this movement, the South Korean government implemented two policies restricting unhealthy food sales in school stores: 1) a food‐based policy enacted in 2007 restricts specific food sales (e.g., soft drinks), and 2) a nutrient‐based policy enacted in 2009 restricts energy‐dense, nutrient‐poor (EDNP) food sales in school stores. The purpose of the study was to assess the effects of the two policies on the school store food environment.Foods sold in stores located in middle and high schools in Seoul, South Korea were observed before (2006, 15 stores) and after (2013, 12 stores) implementation of the two school store policies. After controlling for the total number of food types offered in school stores and school characteristics (school level, private/public, students’ sex, and income level), numbers and percentages of food types in each category were compared between 2006 and 2013. Also, number and percentage of EDNP foods in 2013 were examined using mixed models with school districts as random effects. All statistical analyses were conducted using SAS 9.4 (SAS Institute, Inc., Cary, NC).The mean number of food types offered in school stores was significantly higher in 2013 (102.3 items) than in 2006 (41.1 items; p<0.001), even after adjusting for school characteristics (p=0.022). When controlling for the total number of food types and school characteristics, the mean number of soft drinks offered in a school store in 2013 (0.3 items) was significantly lower than in 2006 (1.9 items, p=0.032). Soft drinks, the target of the 2007 policy, were still available in 50% of school stores observed in 2013, while 60% of school stores observed in 2006 offered soft drinks. In contrast, EDNP foods, the target of the 2009 policy, were available in all school stores observed in 2013, and represented about 7.6% of food types offered.In school stores in South Korea, a food‐based policy that prohibits soft drinks appears to have been more effective for decreasing availability of restricted items than a nutrient‐based policy. Neither of the two policies, however, eliminated access to unhealthy foods in school stores. To improve school store food environments, alternative strategies such as requiring healthy food sales are likely needed.Support or Funding InformationThis study was supported by the Walker Institute of International and Area Studies, University of South Carolina.