bluuebunny/crossref_metadata_2025 huggingface dataset:
Exercise‐Like Mechanical Stimulation of Soleus Feed Arteries (SFA) Attenuates Age‐Induced Endothelial Dysfunction
Authors: Seawright John , Luttrell Meredith , Woodman Christopher
Published: June 2021

Objective

To determine the mechanism of exercise‐induced attenuation of the detrimental effects of aging on endothelial function. We tested the hypothesis that exercise‐like mechanical stimulation of aged SFA with an acute increase in intraluminal pressure in combination with an increase in intraluminal shear stress would induce greater improvements in endothelium‐dependent dilation than an acute increase in intraluminal pressure alone. Methods: SFA from young and old, Fischer 344 rats were pressurized at 90 cmH20 or 130 cmH20 (P130). P130 arteries were exposed to no shear stress (0 dyn/cm2) or high shear stress (~65 dyn/cm2) for 1 h. Following the 1 h treatment period, pressure in the P130 arteries was reduced to 90 cmH2O for examination of endothelium‐dependent [acetylcholine (ACh)] and endothelium‐independent [sodium nitroprusside (SNP)] dilation.

Results

ACh‐induced vasodilation was impaired in old SFA compared to young SFA. Mechanical stimulation with increased pressure for 1 h improved ACh‐induced dilation in old SFA. Stimulation of old SFA with an increase in pressure plus shear stress also improved ACh‐induced. There were no between‐group differences in SNP‐induced dilation.

Conclusion

These results indicate that stimulation with an acute increase in intraluminal pressure alone or in combination with an acute increase in shear stress improves endothelium‐dependent dilation. Research support: AHA grant 0765043Y, AHA grant 4150031, The National Space Biomedical Research Institute through NCC 9‐58 and a Sydney and JL Huffines Institute of Sports Medicine Graduate Student Research Grant.
The Effect of the Rho–kinase Inhibitor (Y‐27632) on the Relaxation of Thromboxane A2 mimetic (U‐46619) Induced Contraction in the Presence and Absence of the Endothelium
Authors: Danborno Angela , Monnet Paige , Orr James
Published: June 2021

Previous work from this laboratory has shown that contraction of aortic vessels treated with the thromboxane mimetic (U‐46619) persists for a much longer time compared to contractions evoked by other agonists. The slow relaxation in response to the TxA2 mimetic is dependent on activation of Rho kinase since an inhibitor of Rho kinase (Y‐27632) evokes a faster relaxation. The current experiments are designed to determine if production of nitric oxide (NO) contributes to the relaxation of blood vessels treated with the Rho kinase inhibitor. In order to eliminate production of NO, vessels were either denuded with forceps to remove the endothelium or treated with L‐NAME (specific inhibitor of NO). Isolated segments (n=75) of aorta from white New Zealand rabbits (n=21) were divided into two groups; in the first group the endothelium was denuded using forceps while in the second group the NO synthesis was inhibited by using L‐NAME (100µM). Acetylcholine relaxation was significantly different between rings with endothelium and rings without endothelium (P<0.001). Isolated segments of rabbit aorta were treated with U4 (0.5 µM) followed by addition of the Y2 (1.0 µM). Following treatment with Y2, there was no significant difference between the E+ and E‐ vessels both in forceps denuded vessels (P=0.57) and L‐NAME treated vessels (P=0.68). We therefore concluded that, even though Y2 significantly reduced the sustained contraction induced by U4, it does not require the release of nitric oxide from the endothelium for its action.
Modeling of the PTF1‐L/Foxa2 Transcription Factor Complex Controlling Pancreatic Development
Authors: Coats Ward , Pedigo K , Noble G , Glispin C , Agha A , Bazaldua A , Aranoff M , Bennett H , Crowling A , Gonzales N , Montoux A , Espinoza A , Almazan S , Allman C , Kaye C , Allman J , Crane B , Villegas A , Broughton B , McDonald Ray
Published: June 2021

Students at Hillcrest High School in Dallas, Texas participate in a research program at the UT Southwestern Medical Center to study the structure of a transcription factor complex crucial to the embryonic development of the pancreas. Children without a functional Ptf1a transcription factor are born with a defective pancreas and are severely diabetic. The active form of Ptf1a is a trimeric complex composed of a common E‐box binding protein (e.g., E12/47), Ptf1a and Rbpj or Rbpjl. The Rbpj form of the complex (PTF1‐J) is required for the early stage of pancreatic development. Subsequently, the Rbpjl‐form(PTF1‐L) is required for the formation of acinar cells of the exocrine pancreas. Recruitment of Foxa2 to PTF1‐L bound sites of pancreatic genes occurs during the final maturation step of pancreas development. The Hillcrest SMART (Students Modeling A Research Topic) Team has manufactured a model for the PTF1‐L/Foxa2 transcription factor complex using 3D printing technology. The students using Pymol, Jmol and the known structures for Rbpj/Notch, MyoD, E12/E47 and Foxp2 generated the atomic coordinates for the model. The model provides the orientation of the Ptf1a/E12 heterodimer relative to Rbpjl and Foxa2 and characterizes interactions formed between Ptf1a and a hydrophobic pocket present in the beta‐trefoil domain of Rbpjl. Determination of the structure for the PTF1‐L/Foxa2 complex will help elucidate the structural determinants and the mechanism for the DNA binding of these complexes.
Renin‐Angiotensin System in Trained Hypertensive Women During Climacteric Period
Authors: Zanesco Angelina , Sponton Carlos , Jarrete Aline , Anaruma Chadi , Fernandes Tiago , Fernandes Fernanda , Oliveira Edilamar , Casarini Dulce , Esposti Rodrigo
Published: June 2021

Background

Epidemiological studies have shown that the incidence of cardiovascular diseases (CVD) in women increases dramatically during climacteric phase. However, the underlying mechanisms are not fully understood.

Aims

To evaluate the components of renin‐angiotensin system (RAS: ANG I, ANG II, ANG‐(1‐7) and ACE activity at baseline and after aerobic exercise training in hypertensive comparing with age‐matched normotensive women.

Methods

Aerobic exercise training (AET) consisted of 24 sessions in treadmill, 3 times/week, 30/40 minutes for each session, iAnthropometric, cardiovascular and biomarkers parameters were measured.

Results

Hypertensive women (HT) showed higher levels of Ang I, Ang II and Ang‐(1‐7), (232, Δ=240%; 365 Δ=90% and 320 pmol/mL, Δ=140%) as compared with normotensive group (NT). No changes were found in ACE activity at baseline for both groups. In the HT group, AET was effective in lowering blood pressure, systolic (5.4%) and diastolic (5.7%), accompanied by a reduction in Ang I and Ang II levels as well as increased activity of SOD and catalase, respectively. In the NT group, we found a reduction in systolic blood pressure accompanied by an increase in SOD activity and decrease in Ang II after AET. Ambulatory blood pressure monitoring showed a reduction in systolic blood pressure in normotensive women after AET that was accompanied by reduction in ACE activity.

Conclusions

Our findings show that RAS is up‐regulated in HT women. In addition, AET was efffective in lowering blood pressure with significant reduction in RAS components in both groups.

Financial Support: FAPESP
The Anti‐inflammative Effects of Evens Blue on Compound48/80 Induced Anaphylactic Shock of rat
Authors: Luo Chi‐Lun , Lin Shiuan‐Yea , Fu Yaw‐Syan , Huang Hung‐Tu , Lu Tzong‐Shi
Published: June 2021

This study demonstratedthat pretreated with Evans blue could prevent the compound 48/80 (C48/80) induced allergic circulatory shock and systemic inflammation.Different groups of Sprague‐Dawley rats received i.v. injection of a dose of Evans blue (0, 5, 10, or 50 mg/kg) just 20 sec prior to i.v. injection of C48/80 (200 μg/kg, over 2 min) that was followed by Evans blue to total dose 50 mg/kg as the tracer dye. The results of study found that pretreatment with Evans blue in a dose of 10 or 50 mg/kg could inhibit C48/80‐induced sudden drops in mean arterial and pulse pressures, and pretreatment with Evans blue in a dose of 5, 10, or 50 mg/kg inhibited C48/80‐induced extensive plasmaextravasation, mast cell degranulation, and edema formation in various organs including the airways, esophagus, and skin. In conclusion, Evans blue pretreatment prevented rats from C48/80‐triggered allergic shock and systemic inflammation, possibly mainly due to inhibition of mast cell degranulation.
Physical Activity Assessed with Accelerometer is an Accurate and Independent Predictor of Mortality in Patients with Advanced Heart Failure
Authors: Rullman Eric , Gustafsson Thomas
Published: June 2021

Background

It is generally acknowledged that in the population as whole, larger volumes of physical activity and a high physical capacity is associated with longevity. In heart failure, physical capacity expressed as peak VO2, is one of the most, robust prognostic factors established. Recent work has put forward the volume of physical activity in daily life as a relevant prognostic aspect in heart failure. Patients with heart failure often display a distinct pattern of walking characterized of short step‐length and frequent short pauses. In the present study we test if this 1) can be assessed using accelerometers and 2) can be used in a prognostic model.

Methods: 60 patients with advanced heart failure (NYHA III, peak VO2 <20 ml/kg and LVEF <35%) underwent exercise test with peak VO2, echocardiography and routine chemistry. Daily activity was assessed by an accelerometer worn attached to the waist during waking hours for 7 consecutive days. Mortality over 5‐years was 52%. The analysis focused on episodes with high‐recorded activity, which was identified by calculating a rolling mean. From these episodes information on average activity was calculated along with measures of variance. Cox proportional hazards regression was used to analyze the data.

Results: Peak activity variance was strongly and independently correlated with mortality and increased accuracy when added to peak VO2 and the Heart Failure Survival Score prognostic model.

Conclusion

Peak activity variance is a promising novel prognostic marker in heart failure and it is a measure of physical activity independent of physical capacity.
Regulation of DAPK activity attenuates neuronal cell death in transient focal cerebral ischemic rats
Authors: Won Jinyoung , Hong Yonggeun
Published: June 2021

Background

Death‐associated protein kinase (DAPK), a positive mediator of many forms of cell death, is activated by glutamate excitotoxic signaling pathways after events such as cerebral ischemia. Purpose: We herein explored whether DAPK was an essential component of programmed neuronal cell death, by downregulating the activity thereof using an oxazolone‐based DAPK inhibitor. Results: In a focal cerebral ischemic (MCAO) model, rats exhibited brain injury accompanied by morphological changes, and altered molecular expression patterns, indicative of neuronal cell death. However, during DAPK inhibition, morphological differences in the dendrites of pyramidal neurons, and differences in programmed cell death, were observed compared to MCAO vehicle‐only rats. Significant decreases in Bax, caspase‐6, and LC3 expression levels were observed. In addition, a significant increase in Bcl2 expression was observed in the DAPK‐downregulated group compared to MCAO vehicle‐only rats, whereas the ischemic injury brain volume was reduced in MCAO rats treated with DAPK inhibitor vs. vehicle (P < 0.05). Suggestion: These data indicate that DAPK inhibition confers protection against neuronal cell death and cerebral ischemic injury. Accordingly, DAPK downregulation exhibits a therapeutic potential in treatment of transient focal ischemia and neurodegenerative diseases.

Funding: 2012R1A1A2005089, 2013R1A2A2A01067169, KGM4611512
The Role of Wip1 in Regulating the Protumorigenic Senescence‐Associated Secretory Phenotype
Authors: Tapia Roberto , Flanagan Kevin , Stewart Sheila
Published: June 2021

Senescent cells are known to accumulate in tissues with age. They are often characterized by a permanent cell cycle arrest and altered secretory profile referred to as the senescence‐associated secretory phenotype (SASP). The release of SASP factors—which include proinflammatory cytokines and growth factors—creates a milieu that can promote preneoplastic cell growth. The mitogen‐activated protein kinase p38 (p38MAPK) is a transcriptional and post‐transcriptional regulator of various SASP factors. Relative to its activation in response to lipopolysaccharide treatment, p38MAPK phosphorylation due to senescence stimuli is dramatically slower. To elucidate the mechanism of these slow kinetics, we focused on wild‐type p53‐induced phosphatase 1 (Wip1), which inactivates p38MAPK by dephosphorylating a conserved threonine residue. The loss of p53 function results in a more rapid and robust activation of p38MAPK in response to senescence. Additionally, Wip1 is rapidly induced by senescent stimuli, with expression decreasing over time, mirroring p38 activation kinetics. Therefore we hypothesize that senescent stimuli induces p53 to activate Wip1, which dephosphorylates p38MAPK, thereby delaying p38MAPK induction. Preliminary results from immunoblot analysis of senescent fibroblasts indicate a delay in phosphorylated p38MAPK induction on the first day after bleomycin treatment followed by robust activation in subsequent days. Further studies are focused on using the CRISPR‐Cas system to knock out Wip1 expression in order to investigate its role as a regulator of p38MAPK and the SASP in response to senescence.
Not So Hot Rods: Mutations in Rhodopsin Kinase in Regards to Oguchi Disease
Authors: Arnholt Mark , Czerniak C , Daley S , Bade J , Kellicut A , Semler L , Krupski L , Killoren J , Wilkins C , Wilk Melissa
Published: June 2021

The average person's eyes adapt to darkness within minutes. For those with Oguchi's disease, adaptation can be slowed to several hours. Oguchi disease is an autosomal recessive disorder that results in greatly slowed phototransduction. Phototransduction is a cascade reaction beginning with a photon activating rhodopsin in the rod and leading to hyperpolarization of the cell. Oguchi disease is caused by mutations in rhodopsin kinase which prevent the phosphorylation of rhodopsin, lowering rhodopsin's affinity for arrestin. This reduced ability to bind arrestin decreases the speed in which rhodopsin is deactivated and prepped to reactivate. After a long period in a dark environment, the rhodopsin is eventually deactivated by arrestin, allowing it to be recycled. The Hartford Union High School SMART (Students Modelling a Research Topic) Team has designed a model of rhodopsin kinase to investigate its structure‐function relationship. Oguchi disease can be caused by two different mutations in rhodopsin kinase: large deletion or point mutation. In our 3D model, we will highlight the complete deletion of exon five, the partial deletion at the C‐terminus, and point mutations in the catalytic domain (Val380Asp and Pro391His) that cause Oguchi disease. Understanding the structure‐function relationships of rhodopsin kinase could shed more light on night blindness. This program is supported by a grant from NIH and CTSA.
Development of conditioned place aversion to spontaneous morphine withdrawal during estradiol replacement
Authors: Martinez‐Casiano Karla , Ramos‐Ortolaza Dinah , Chamorro Jose , Torres‐Reveron Annelyn
Published: June 2021

Opiate withdrawal syndrome works as negative reinforcement contributing to the maintenance of drug seeking behavior and consequently relapse. In animal research, withdrawal‐induced conditioned place aversion (CPA) has been widely used to investigate the negative associations formed during drug withdrawal. Studies using it's counterpart (CPP) have reported sex differences with females developing CPP to lower doses of psychostimulants than males, an effect highly dependent on ovarian hormones. It is still unknown how ovarian hormones might affect CPA during spontaneous opiate withdrawal. We hypothesized that in females, estrogen is necessary to develop CPA during spontaneous withdrawal from chronic morphine. Adult ovariectomized female rats (n=27) were exposed to chronic morphine regimen and somatic signs of spontaneous morphine withdrawal were assessed at 14 and 84 hours after morphine cesation. Estradiol replacement (10μg/0.2mL, s.c.) or vehicle (sesame oil) started with the last injection of morphine until sacrifice. At 14 hours following morphine cesation (early withdrawal), we confined them to one side of a dual choice box where the compartments differ in the floor and wall cues. In contrast to our previous observations in normal cycling female rats, morphine treated females with estradiol replacement did not show CPA. These findings suggest that estradiol must be present during the acquisition of dependence and not only during the withdrawal phase for avoidance responses to happen. Supported by 2G12MD007579‐29.
Unraveling the avian paradox: Avian resistance to protein glycation
Authors: Sweazea Karen , Borges Chad , Zuck Jessica , Rayle Sean
Published: June 2021

Avian plasma glucose (PGlu) concentrations are naturally 1.5‐2 times those of mammals of similar body mass. Avian tolerance of exceptionally high PGlu is enigmatic considering that mammals with similar values would suffer severe pathologies stemming from hyperglycemia‐induced protein glycation. What is not currently known is how birds protect circulating proteins and the vasculature from high PGlu. The purpose of this study was to explore this “avian paradox.” Because protein glycation is an exothermic chemical process, we hypothesized that the unique physiology of birds (higher body temperatures than mammals) would help protect them from protein glycation. Since PGlu concentrations are inversely correlated with body mass, we measured percent glycated albumin in the plasma of three species of birds with varying body masses and body temperatures: house finches (Haemorhous mexicanus, 16‐27g, 42.5ºC), mourning doves (Zenaida macroura, 90‐130g, 41.5ºC) and mallard ducks (Anas platyrhynchos domesticus, 981‐1492g, 40.2ºC). Using top down mass spectrometry we discerned that PGlu does not predict albumin glycation demonstrating the generic, species agnostic nature of the avian paradox. In addition, birds with the highest body temperature (finches) have the lowest albumin glycation in comparison to doves and ducks (6.17±0.95%, 11.7±1.8%, 9.70±0.7%, respectively; p=0.05). These data support the hypothesis that higher body temperatures in birds may protect from protein glycation, which will be examined further through in vitro studies comparing percent glycation of avian and mammalian albumin.
Incorporation of SDF‐1α into Pre‐formed Dextran Sulfate and Chitosan Nanoparticles
Authors: Zaman Paula , Wang Julia , Li Tina , Wang Weiping , Kohane Daniel , Loscalzo Joseph , Zhang Ying‐Yi
Published: June 2021

Dextran sulfate (DS) and chitosan (CS) nanoparticles (NPs) have a glycan matrix that may be useful for in vivo delivery of proteins. Current procedures for the formation of DS‐CS NPs with incorporated proteins is to first combine DS or CS with the protein of interest and then proceed to particle formation. In general, this process requires a significant amount of protein for particle formation, and after the reaction the unincorporated protein cannot be easily recovered for future incorporation. Considering the high cost and limited availability of various recombinant therapeutic proteins, in this study we investigated whether proteins can be incorporated efficiently in pre‐formed DS‐CS NPs. To do so, DS‐CS NPs were formulated, prepared on a large scale, and lyophilized. The reconstituted DS‐CS NPs were sized 333±16 nm, with a polydispersity of 0.119±0.026 and zeta potential of ‐32.4±1.4 mV. Stromal cell‐derived factor‐1α (SDF‐1α) was loaded onto the DS‐CS NPs at various concentrations. At the ratio of SDF‐1α to DS of 0.02:1, 85±8 % of the loaded SDF‐1α was incorporated in the NPs. The resulted particles (SDFNPs) had a diameter of 393±17 nm, a polydispersity of 0.147±0.032, and a zeta potential of ‐28.6±1.9 mV. The incorporated SDF‐1α had the same chemotactic activity as that of free SDF‐1α. Administration of aerosolized SDFNP to the lungs of rats showed that ~ 30% SDF‐1α remained in the tissue at 72 hr after the delivery, while free SDF‐1α was mostly cleared from the lung (~97%) after 16 hr. This study shows that pre‐formed DS‐CS NPs incorporated SDF‐1α with high efficiency, and can be a useful vehicle for delivery of recombinant therapeutic proteins to the lung parenchyma.
Role of Hypoxia Inducible Factor (HIF‐1α) on mitochondrial function in Insulin Resistance Muscle Cells
Authors: Araújo Michel , Lima Tanes , Sampaio Igor , Teodoro Bruno , Bomfim Lucas , Queiroz Andre , Passos Madla , Santos Jonathas , Carneiro Everardo , Silveira Leonardo
Published: June 2021

Insulin resistance is a common feature in diabetic population. One target that has been given some attention is the transcriptional factor hypoxia inducible factor (HIF‐1α). Our proposal was to evaluate the role of HIF‐1α in insulin resistant skeletal muscle cells (Ethics protocol no. 063/2012 FMRP‐USP). After differentiation, the cells were exposed to different nutrients: glucose, palmitic acid 600 µM and AICAR (500 µM). The oxygen consumption was measured using a Clark‐type electrode (Hansatech Instruments). Analyses of western blotting were performed for proteins quantifying HIF‐1α. In addition, the mRNA level of HIF‐1α and β‐actin was determined by qPCR‐Realtime. The oxygen consumption was significantly increased in the presence of AICAR in compared to control (p<0.05). The mRNA levels HIF‐1α showed an increased expression when compared to the mRNA levels HIF‐2α in muscle cells (p<0.05). The mRNA levels of HIF‐1α showed a significant increase in AICAR compared to control and palmitic acid treated cells (p<0.05). In addition, AICAR treatment increased HIF‐1α gene expression (p<0.05). The elevated HIF‐1α was associated with reduced reactive oxygen species (ROS) production and elevated insulin response as indicated by Akt phosphorylated levels. These results, therefore, suggest that under elevated expression of HIF‐1α is an important mechanism to protect the cells against insulin resistance and mitochondrial dysfunction.Financial Support: FAPESP Process number: 2012/17416‐2 ‐ Corn Products of Brazil.
Diet Board as Strategy to Development of Fetal Programming on Female Rats
Authors: KANUNFRE CARLA , Oliveira Larissa , Costa Nathalia , Lecke Sheila , Morsch Debora , Spritzer Poli
Published: June 2021

Controlled animal studies supply an important correlation between maternal nutrition (during pregnancy and lactation) and risk of disease in later life of offspring. Here we report the use of diet board as strategy to development of fetal programming and the effects produced in mothers and female offspring postnatal fed or not with hypercaloric diet. The diet board consisted of two aspen boards placed into the rat cage with vertical holes filled with food pellets, the unique way the rats obtained feed. Wistar pregnant dams were randomized into one of two groups, control and diet board. At weaning, female offspring were randomly assigned to receive either standard rat chow or hypercaloric diet (17%Kcal of sucrose, 10%kcal of primex shortening). The diet board reduces the weight gain on lactation (p=0.004) and gestation length (p=0.04). In addition mothers fed by diet board presented lesser fat in the adipose tissue depots (p=0.02). Concerning to effects of diets in the postnatal period, offspring did not differ on growth, energy intake, final body weight, Lee index and levels of insulin. In turn, hypercaloric diet had effects on visceral fat that was confirmed by adiposity index (p=0.01), glucose concentration (p=0.009) and ipITT (p=0.006). These data indicate that diet board as strategy to development of fetal programming produces effects on mothers that have impact on insulin and glucose tolerance of adulthood offspring manifested in the animals fed with hypercaloric diet.

Grant Funding Source: Brazilian National Institute of Hormones and Women's Health and FIPE – HCPA, Brazil.
Effects of Endurance Exercise Training on Gastrointestinal Barrier
Authors: Holland A. Maleah , Hyatt Hayden , Smuder Ashley , Sollanek Kurt , Morton Aaron , Roberts Michael , Kavazis Andreas
Published: June 2021

The gastrointestinal (GI) tract is an important organ system that can affect exercise performance. Specifically, exercise causes a redistribution of blood flow away from the GI tract, which can alter GI barrier permeability. Therefore, in these experiments we investigated the effects of endurance exercise training on GI tight junction and nutrient transporter gene expression. Sixteen female Sprague Dawley rats (4 month old) were assigned to control (CON) or endurance exercise‐training (EXE) groups (n = 8 per group). EXE animals were trained on the treadmill for two weeks at a speed of 30 meters per minute at 0° incline for 60 minutes per day. CON and EXE animals were sacrificed (24 hours after the final training bout) and ileum was stored for analyses. Evaluation of the tight junction revealed that the ileum of EXE animals had significantly (p<0.05) lower CLDN1 mRNA expression compared to CON animals. However, no significant (p>0.05) changes were detected in OCLN or ZO1. Similarly, there were no significant (p>0.05) changes in the mRNA expression of six nutrient transporters (SLC 5A8, SLC 7A6, SLC 6A19, SLC 7A7, SLC 7A2, SLC 16A10). These findings suggest that two weeks of endurance exercise training does not result in any changes in the gene expression of key nutrient transporters. Likewise, exercise did not alter gene expression of OCLN (involved in regulation of the tight junction paracellular permeability barrier) or ZO1 (involved in signal transduction at cell‐cell junctions). Interestingly, exercise training reduced the expression of the tight junction gene CLDN1 (important for cell‐to‐cell adhesion) that may be suggestive of a “leaky” gut following training.
Blunted Non‐Shivering Thermogenesis in Obese Relative to Non‐Obese Adult Males
Authors: McMillan Andrew , White Matthew
Published: June 2021

PURPOSE/HYPOTHESIS

It was hypothesised that obese (O) relative to non‐obese (N‐O) men would have a reduced non‐shivering thermogenesis (NST) response to mild cold exposure. METHODS: Four college‐aged N‐O males with 18.7 % body fat (BF) and 4 O males with 33.9% BF, both assessed by DEXA, volunteered for an SFU Office of Research Ethics approved study. Measures included oxygen consumption (VO2, mL/min/kg), rectal temperature (TRE,°C), surface heat flux (HF, W m‐2) and skin temperatures (TSK,°C) on the right and left supraclavicular areas, chest, posterior shoulder, upper arm, abdomen and thigh. Surface electromyography (EMG) was used to assess the contributions of shivering thermogenesis (ST) and supraclavicular skin temperatures were assessed using a Forward Looking Infrared (FLIR) camera. After an overnight fast each volunteer, wearing only shorts, sat in a climatic chamber at 26°C for 90 min and then at 19°C for 90 min. RESULTS: The TRE in both groups remained at 36.73±0.64°C in the 26 and 19°C exposures. At 19°C the O had a lower mean TSK of 29.11±0.39°C relative to the N‐O mean TSK of 30.58±0.39°C (p < 0.05), a lower mean HF of 78.52±9.07 W m‐2 relative to that of 97.05±4.38 W m‐2 (p < 0.05) for the N‐O and a lower mean VO2 of 2.24±0.59 mL/min/kg relative to that of 4.03±0.52 mL/min/kg (p<0.05) in the N‐O. The O supraclavicular HF of 82.64±26.59 W m‐2 was lower than that of 115.69±16.76 W m‐2 (p < 0.05) in the N‐O. FLIR imaging showed O supraclavicular TSK of 30.78±0.54°C was lower than that of 32.66±0.21°C (p<0.05) for the N‐O.

CONCLUSION

Despite lower skin temperatures and the same rectal temperature, O men appear to have lower NST relative to N‐O men and this suggests they have a lower brown adipose tissue activation during mild cold exposure.

Supported by NSERC and CFI
Anti‐apoptotic effect of combined melatonin and exercise following focal cerebral ischemic in rats
Authors: Lee Minkyung , Hong Yonggeun
Published: June 2021

Ischemic stroke occurs when blood flow to the brain is interrupted, depriving the affected area of oxygen and nutrients, which can cause apoptosis. Here we investigated the effect of melatonin and exercise on apoptosis in focal cerebral ischemia at acute, sub acute, and chronic stages. Sprague‐Dawley (SD) rats (8‐week‐old) were randomly assigned to one of four groups; all underwent middle cerebral artery occlusion (MCAo), and received no treatment, twice daily melatonin (10 mg/kg) at 7:00 and 19:00, twice daily treadmill exercise (20 m/min, 6 days/week) at 17:00 and 22:00, or both melatonin and exercise. Exercise significantly reduced infarct volume as measured by 2%triphenyltetrazolium chloride (TTC) staining. Combined melatonin and exercise decreased expression of the pro‐apoptosis marker Bax (p < 0.05 relative to MCAo alone) at the chronic phase, and increased expression of the anti‐apoptosis marker Bcl2 (p < 0.05). Moreover, in these rats, the ratio of Bax to Bcl‐2 expression at the chronic phase was significantly lower than that in rats whose MCAo injury was not treated (p < 0.05), following an increase at the acute phase. Therefore, combined melatonin and exercise should be further explored as a means of reducing apoptosis and necrosisfollowing stroke.

Funding: 2012R1A1A2005089, 2013R1A2A2A01067169, KGM4611512
Acute Effects of External Pneumatic Compression on Peripheral and Central Hemodynamics
Authors: Vincent‐Horta Lisa , Sanders David , Martin Jeffrey , Beck Darren
Published: June 2021

Use of external pneumatic compression (EPC) to improve recovery after exercise is increasing. However, the acute hemodynamic effects of EPC have not been determined. The purpose of this study was to investigate the acute effects of EPC on the aortic pressure waveform (AoPW) during EPC therapy. Twenty (n=20) young participants (23.5±3.9 years) were included in this study. Analysis of the AoPW was evaluated continuously using applanation tonometry before, during, and after a single 1‐hr therapeutic session of EPC. A sequential EPC device was employed with target inflation pressures of ~100 mmHg of compression. Peripheral systolic blood pressure was increased by 5.8±1.3 mmHg during EPC and remained elevated 10 minutes post treatment, p<0.05. Aortic systolic blood pressure was increased by 5.9±1.1 mmHg during EPC and remained elevated 10 minutes post treatment, p<0.01. Both peripheral and aortic diastolic blood pressure were significantly increased by 5.1±0.9 and 4.8±0.9 mmHg, respectively, during EPC and remained elevated 10 minutes post treatment, p<0.05. Peripheral and aortic mean arterial pressure were increased by 4.2±1.0 and 4.3±1.1 mmHg, respectively, during EPC and remained elevated 10 minutes post treatment when compared to baseline values, p<0.05. EPC at target inflation pressures of 100mmHg increases total peripheral resistance to lower limb blood flow which results in increases in peripheral and central blood pressures during therapy and persists at least 10 minutes post treatment.
Time Course of Mitophagy‐Related Signals in Skeletal Muscle Following a Single Bout of Aerobic Exercise in Mice
Authors: Jannig Paulo , Voltarelli Vanessa , Bozi Luiz , Brum Patricia
Published: June 2021

This study aimed to investigate mitophagy‐related signals in skeletal muscle following a single bout of aerobic exercise in mice. C57BL6 mice were submitted to a single bout of treadmill aerobic exercise for 80 minutes at 60% of maximal speed achieved in a graded treadmill test. Skeletal muscles were harvested at rest, immediately after the bout of aerobic exercise and after 3, 6, 12 and 24h of recovery. One hindlimb was used for fresh isolation of skeletal muscle mitochondrial‐enriched fraction (MF), and contralateral muscles were immediately frozen. Immunoblotting for LC3, p62 and Bnip3 were performed either in quadriceps muscles or MF. qPCR were performed to evaluate mRNA levels of LC3, p62 and Bnip3 in quadriceps muscles. No protein was differentially expressed in total lysate of quadriceps muscle. However, LC3‐II levels were significantly increased in MF immediately after the bout of aerobic exercise (72.5%) and after 12h of recovery (63.3%), whereas p62 protein levels were increased at 6 (30%) and 12h (62.5%) of recovery. Bnip3 protein levels displayed a trend toward to increase (p=0.06) after 3h of recovery (36.4%). No difference was found in mRNA levels of LC3, p62 and Bnip3 at any time point. Collectively, these results suggest that mitophagy signaling is increased during aerobic exercise and decreases after its cessation. Interestingly, the retake of mitophagy signaling after 12h of recovery suggests that mitophagy plays an important role in skeletal muscle mitochondrial remodeling to acute aerobic exercise stimulus, independently of transcriptional regulation. Thus, these results provide new insights into aerobic exercise‐induced mitophagy and mitochondrial remodeling.

Financial support: FAPESP 2013/21065‐3
Effects of Branched‐Chain Amino Acids and Low‐Iron Containing Diet on Non‐Heme Iron and Muscle Mass of Aging Rats
Authors: Kim Yuho , Men Sambo , Liang Chen , DeRuisseau Keith
Published: June 2021

The increased iron status of aging skeletal muscle was previously shown to be associated with the development of sarcopenia. Thus, lowering muscle iron status by administering a low‐iron containing diet may attenuate muscle mass loss with advancing age. Moreover, iron homeostasis and protein synthesis may be influenced by mTOR signaling, which might be altered by branched‐chain amino acids (BCAA). The purpose of this study was to determine how chronic administration of BCAA and/or low‐iron containing diet affects muscle iron status and mass in aging rats. Male F344BN rats (aged 29 months) were fed one of the following diets for 12 weeks: Control (CON: AIN‐93M; iron 35 ppm; n=7), BCAA (control + 2×BCAA; n=6), Low‐iron (LID: control diet with iron 2‐6 ppm; n=5), and Combined (CBM: control + 2×BCAA with iron 2‐6 ppm; n=6). Gastrocnemius muscles were removed, weighed, and analyzed for non‐heme iron (NHI). After 12 weeks, all groups increased body mass but there was no difference between groups (p>0.05). Although the LID group displayed ~23% lower muscle NHI compared to CON animals (1387 ± 251.0 vs. 1823 ± 309.6 nmol/gww), the differene was not stastically significant (p>0.05). Moreover, BCAA and Combo diets also showed no effect (2083 ± 239.9 and 2123 ± 250.3 nmol/gww, respectively; p>0.05) on muscle NHI levels compared to CON animals. Muscle mass was similar (p>0.05) between all dietary intervention groups: CON, 2.60 ± 0.28 mg/g body mass (BM); BCAA, 2.75 ± 0.15 mg/g BM; LID, 2.93 ± 0.09 mg/g BM; CMB, 2.87 ± 0.11 mg/g BM. These preliminary results suggest that long term administration of low dietary iron, BCAA, or a combined diet of BCAA with low iron to aging rats does not reduce uscle NHI or alter muscle mass. Funding provided by Syracuse University Office of Research.
Pivotal role of melatonin plus exercise as a neuroregenerator following focal cerebral ischemic injury
Authors: Park Sookyoung , Lee Seunghoon , Hong Yonggeun
Published: June 2021

Among the numerous studies related to therapeutic mechanism following stroke, neurogenesis plays a critical role. Therefore, we hypothesized that combination therapy with melatonin and exercise might exert on the neurogenesis after focal cerebral ischemia. Sprague‐Dawley rats were randomly divided into control (Con) and middle cerebral artery occlusion (MCAo) groups treated vehicle (Veh), melatonin (MT), exercise (EX), and melatonin with treadmill exercise (MT+Ex). MCAo‐induced neurological deficits were improved by melatonin with and without exercise. Furthermore, we confirmed the expression of NeuN and Doublecortin were significantly reduced in MCAo+Veh, while melatonin with without exercise attenuated these alterations. The expression of BDNF, in particular mature‐BDNF was increased, but not pro‐BDNF after MCAo. These changes were reduced at chronic phase of MCAo. GFAP expression was increased in lesion area of MCAo+Veh, then melatonin with and without exercise decreased these changes. By histological examination, MCAo‐induced infarction volumes were reduced by melatonin with and without exercise. We found that neurite length from perikaryon was markedly diminished than control rat. However, melatonin plus exercise promotes neurite outgrowth from penumbra to infarct core lesion. Thus, these results demonstrate that melatonin plus exercise could contribute to neuroregeneration and support the potential use for stroke.

Funding: 2014R1A1A3051724, 2013 Post‐Doctoral Research Program of Inje University, 2012R1A1A2005089, 2013R1A2A2A01067169, KGM4611512
Obesity Induces Further Autonomic Impairment in Sheep Exposed Antenatally to Betamethasone
Authors: Lawson Matthew , Shaltout Hossam , Diz Debra , Figueroa Jorge
Published: June 2021

Glucocorticoids including betamethasone are routinely administered to women entering into early preterm labor to facilitate fetal lung development and decrease infant mortality; however, fetal betamethasone exposure (BMX) may lead to deleterious long term consequences. In a sheep model of fetal programming, BMX offspring exhibit elevated mean arterial pressure (MAP) and decreased baroreflex sensitivity (BRS) for control of heart rate by 6 month of age. In this study we examined the hypothesis that adding obesity to BMX will have a negative effect on cardiovascular function in these sheep. To test this hypothesis, 19 female sheep at 1 year of age were divided into 4 groups. Lean control (LC, n=6), Lean Beta (LB, n=5), obese control (OC, n=4) and obese beta (OB, n=4). Obesity was induced by allowing the animals to eat ad libitum for 12 weeks and obesity was determined if the sheep showed a 40% weight gain compared to baseline weight. BMX impaired BRS measured as Seq ALL (13 ± 1 in LB vs 23 ± 4 ms/mmHg in LC, p<0.05) while BRS tended to be further impaired in OB (10 ± 1 ms/mmHg, p=0.07 vs LB). BMX reduced heart rate variability measured as rMSSD (47 ±5 in LB vs 84 ± 12 ms in LC). HRV tended to be reduced in the OC group (48 ± 13, p=0.08 vs LC) and in the OB group (39 ± 2 ms, p=0.18 vs LB). MAP was higher in LB vs LC and was further increased in both OC and OB. In human exposed in utero to betamethasone, weight gain exacerbates the risk of developing autonomic dysfunction and cardiovascular disease. Thus, body weight gain should be monitored in these subjects in early adulthood. Support: HD‐47584, GM‐064249
Electrophysiological Properties of Magno‐and Parvo‐Cellular Neurons in Rat Hypothalamic Paraventricular Nucleus
Authors: Shen Yi Ming , Lee So Yeong , Han Seong Kyu , Ryu Pan Dong
Published: June 2021

The hypothalamic paraventricular nucleus (PVN) contains magnocellular neurosecretory neurons (PVN‐MC) projecting to posterior pituitary, and parvocellular neurons projecting to anterior pituitary (neurosecretory), medulla (PVN‐RVLM) and/or spinal cord (PVN‐IML) (presympathetic). These PVN neurons are different in their roles and projections, but the differences in excitability are not well known. In this study, we compared the basic electrophysiological properties of these neuron groups.

The PVN‐MC, PVN‐IML and/or PVN‐RVLM neurons were identified by electrophysiological property (expressing a prominent transient outward rectification) and retrograde dye (FluoSphere‐Red). The spontaneous firing, EPSC and action potential were recorded in the cell‐attached or whole‐cell mode with Axopatch 200B. Data were sampled at 20 KHz using pClamp 8 data‐acquisition and analysis software.

In the voltage clamp cell‐attached mode, the frequency of spontaneous firing in the PVN‐IML neurons was higher than those in the other two groups (PVN‐ RVLM, PVN‐IML, PVN‐MC: 1.4 vs. 2.8 vs. 1.0 Hz, n=30, 27, 29; p<0.05). The mean frequencies of IPSC (5.1Hz, n=11) was lowest and the 37~90% decay time of IPSC (5.6 ms, n=9) in PVN‐IML neurons was shortest, and the PVN‐MC neurons (191.0 mV n=12) had shown the largest amplitude of IPSC (PVN‐RVLM, PVN‐IML: 61 vs. 55 mV n=16, 11; p<0.05). The 37~90% decay time (5.8 ms, n=22) of EPSC in the PVN‐MC cells was also larger than those of the PVN‐RVLM and PVN‐IML neurons (3.2 vs. 2.88 ms, n=14, 16; p<0.05). The properties of action potential were determined in the whole cell current clamp. The amplitude in PVN‐MC was definitely the largest (PVN‐RVLM, PVN‐IML, PVN‐MC: 78 vs. 65 vs. 69 mV, n=20, 10, 17; p<0.05)

These results indicate that electrophysiological properties of three neuron groups were also different. The PVN‐IML neurons were the highest of spontaneous firing, and PVN‐MC neurons have larger input resistance and action potential amplitude of action potential. Functional significance of these differences remains to be studied further.
Renal HCO3‐ Reabsorption Is Differentially Modulated by Water Deprivation Depending on Food / Na+ Intake
Authors: Pessoa Thaissa , Malnic Gerhard
Published: June 2021

Although kidneys are able to perform water balance dissociated from Na+ balance, hypovolemic dehydration, as seen during water deprivation (WD), modifies both. Moreover, WD can occur singly or together with food deprivation (FD) and, therefore, may differently alter such parameters. NHE3 is the major pathway for NaHCO3‐ in the proximal tubule and is important to volume balance, but the effect of WD on it is not well known. The goal of this work was to determine the effect of WD on HCO3‐ reabsorption (JHCO3‐) and the role of food (FI) or Na (NaI) intake in this mechanism. Rats were kept for 24 hs with water ad libitum (CTRL) or in WD, and JHCO3‐ was measured by means of stationary microperfusion. WD decreased by 34% JHCO3‐ (vs CTRL), and this effect was NHE3‐dependent, since the S3226(NHE3‐inhibitor)‐insensitive component of JHCO3‐ was not modulated by WD. Because NaI increases renal Na+ excretion and could influence JHCO3‐, animals were kept in WD and fed with a deficient Na+ diet (DNa), to determine the role of NaI on WD effect. As expected, in the absence of dietary Na+, JHCO3‐ was stimulated. Moreover, despite during WD + DNa, JHCO3‐ has decreased by 13% (vs DNa alone), the inhibitory effect of WD on JHCO3‐ was attenuated (since WD decreased JHCO3‐ by 34% when animals were fed with a CTRL diet). Because others dietary components besides Na+, may influence JHCO3‐, animals were kept in FD and WD. Although NaI was null during both, DNa and FD, JHCO3‐ was not stimulated by this last condition. Besides, the observed attenuation on JHCO3‐ was smaller (JHCO3‐ was 13% for DNa vs DNa + WD and 26% for FD vs FD + WD). These results indicate that WD inhibits NHE3. NaI presents a central role in this inhibitory effect; however NI has also a Na+‐independent component that inhibits JHCO3‐.

Financial support FAPESP, CNPq
Increased Glomerular ET‐1 in Female Sickle Cell Mice is Abolished by Chronic Hydroxyurea Treatment
Authors: Kasztan Malgorzata , Speed Joshua , Pollock David
Published: June 2021

Sickle cell disease (SCD) is associated with glomerular nephropathy leading to the chronic kidney disease. Endothelin (ET‐1), a powerful vasoconstrictor and pro‐inflammatory mediator, is increased in SCD patients and recent evidence suggests it can contribute to the development of glomerulopathy and decline in renal function in SCD. Currently, hydroxyurea is the only therapy demonstrating benefits for SCD patients due to its ability to increase fetal hemoglobin. Therefore, the aim of the study was to determine if elevated glomerular ET‐1 mRNA expression in sickle cell mice is reduced by hydroxyurea treatment and if sex differences exist in this response. Experiments utilized homozygous knockout‐transgenic sickle mice (humanized) from our in‐house colony. Hydroxyurea was administrated via drinking water and the concentration adjusted daily according to intake (50mg/kg/day) for 7 days. Glomeruli were isolated for ET‐1 mRNA. Female sickle cell mice had a 3‐fold increase in glomerular ET‐1 mRNA at baseline compared to male (3.07±0.21 vs. 1.07±0.16 fold change, p<0.05). After treatment with hydroxyurea female sickle cell mice had a significant reduction in ET‐1 expression (from 3.07±0.21 to 1.21±0.12 fold change, p<0.05). Hydroxyurea did not significantly alter glomerular ET‐1 production in male sickle cell. These data support the hypothesis that chronic treatment with hydroxyurea can reduce glomerular ET‐1 production, and possible renal pathologies associated with SCD. Further, sex differences in glomerular ET‐1 expression may play an important role in the development of sickle cell nephropathy.
Effect of Antenatal Betamethasone on Ovine Renal Function in Obese Offspring
Authors: Bi Jianli , Figueroa Jorge , Chappell Mark , Rose James
Published: June 2021

One third of adults in the United States are obese and over 100,000 individuals are born each year after antenatal exposure to glucocorticoids. Some of these individuals become obese. Little is known about effects of antenatal glucocorticoids on responses to angiotensin in obese adult offspring.

We studied the effect of antenatal glucocorticoids exposure on responses to infusions of angiotensin II (ANG II) or angiotensin – (1‐7) (ANG (1‐7)) in 1‐1.5 year old male sheep exposed to either betamethasone (n=3) or vehicle (n=3) at 80‐81 days gestation and overfed to become obese in adulthood. Systemic infusions ANG II (0.5ng/kg/min) or ANG‐(1‐7) (9ng/kg/min) were administered. Blood pressure (BP), renal plasma flow (RPF), glomerular filtration rate (GFR), and filtration fraction (FF) were measured. ANOVA and Student's t test were used for data analysis.

ANG II increased BP and the increase was higher in male obese antenatal betamethasone exposed sheep (MOB) (6.0 mmHg vs. 3.7 mmHg, p=0.04, MOB vs. MOV (male obese vehicle exposed sheep)). Basal RPF and GFR were not different but FF was lower in MOB (F=7.1, p=0.03). Neither peptide significantly changed RPF and GFR. However, ANG‐(1‐7) increased FF more in MOV than in MOB after sodium load (p=0.03, MOV vs. MOB)

The greater increase in BP in MOB suggests that they are more sensitive to ANG II. The lower FF and smaller increase of FF with ANG‐(1‐7) in MOB indicates disproportionate loss of GFR compared with MOV. The data suggest that obesity increases responses to ANG II and reduces responses to ANG‐(1‐7) in antenatal betamethasone exposed males.

Supported by NIH Grants HD‐47584 and HD‐17644.
Effects of Sodium Loading plus Walking on Bone Mineral Content (BMC)
Authors: Angelakos Kailyn , Hew‐Butler Tamara
Published: June 2021

Determine if sodium loading and changes (Δ) in blood sodium concentration ([Na+]) are related to Δ's in BMC after walking.

Methods

2 single‐blind randomized trials: 6 flour tablets (P: placebo trial) or 6 1g‐NaCl tablets (S: salt trial). Tablets ingested after baseline blood and urine collection. Dual energy x‐ray absorptiometry (DXA) scan performed next. After 60 minutes of rest, a 45‐minute treadmill walk was conducted. Immediately post‐exercise, blood and urine were collected. DXA scan repeated. Main outcomes included pre‐ to post‐exercise changes (Δ) in blood [Na+], urine [Na+], and BMC.

Results

14 subjects completed both trials. Significant increases (S vs. P trial, respectively) noted in: post‐exercise blood [Na+] (144±2 vs.140±2mEq/L; p<0.0001) and urine [Na+] (115±53 vs. 64±46 mEq/L; p=0.01); Δ blood [Na+] (3±2m; vs. 0±1mEq/L; p=0.0001) and Δ urine [Na+] (21±36 vs. ‐15±28mEq/L; p=0.006). Significant differences in BMC seen in Δ left rib (‐5.4±7 vs. 0.2±6g; p=0.03), which corresponded to location of ingested tablets pre‐exercise, and Δ total body BMC (‐5.5±27 vs. 14.1±21.4g; p=0.04). Δ blood [Na+] positively correlated with Δ urine [Na+] (r=0.47;p=0.01) and Δ thirst rating (r=0.49; p=0.008). Δ total BMC negatively correlated with: post‐exercise blood [Na+] (r=‐0.43;p=0.02); Δ blood [Na+] (r=‐0.43; p=0.02); and Δ urine [Na+] (r=‐0.47; p=0.01) and positively correlated with Δ left leg BMC (r=0.54;p=0.003) and Δ right leg BMC (r=0.53; p=0.004).

Conclusion

:1) increases in blood and urine [Na+] associated with decreases in total BMC; 2) Δ total BMC linearly related to Δ's in left and right leg BMC after treadmill walking; 3) Reductions in left rib and total BMC closely approximate NaCl ingested (~6g; inactive) before dissolution into bloodstream (active), suggesting localized sensitivity of DXA to NaCl tablets.