bluuebunny/crossref_metadata_2025 huggingface dataset:
Pansteatitis Induced Differential Expression of Inflammatory and Apoptosis Genes in Adipose Tissue: A Glimpse into Pathophysiology of the Condition in the Nile Crocodile.
Authors: Azeez Odunayo Ibraheem , Myburgh Jan , Meintjes Roy , Bosman Anna‐Mari , Featherstone Jonathan , Oosthuizen Marinda , Chamunorwa Joseph Panashe
Published: June 2021

In the quest to understand the pathophysiology of pansteatitis in the Nile crocodile, a condition that was attributed to the recent crocodile die off at the Olifant river, Mpumalanga, the whole transcriptome of the Nile crocodile was sequenced and assembled using whole transcriptome shotgun sequencing data by Illumina RNAseq from RNA obtained from fat body and other adipose tissues.

Total RNA, from abdominal fat body and other adipose tissue from normal farmed Nile crocodiles and samples collected from Nile crocodiles that had died of pansteatitis, were extracted and purified using Qiagen RNA mini prep (Qiagen, USA). RNA samples library were prepped using the Truseq stranded total RNA sample preparation and sequenced on the Illumina Hiseq 2500 with v4 SBS chemistry. Reads were assembled using Tophat (http://tophat.cbcb.umd.edu/) and aligned with reference transcriptome from Crocodylus porosus using Cufflinks (http://cufflinks.cbcb.umd.edu/) for downstream analysis while the differential gene expression analysis was done using Cuffdiff and RSEM (http://deweylab.github.io/RSEM/).

A total of 13,329 genes were identified out which 1541 genes related to inflammatory response and apoptosis were identified. A total of 641 genes were up regulated in the pansteatitis samples as compared to normal adipose tissues using a fold change of 16.0. A total of 70 inflammatory genes were up regulated in the pansteatitis samples including, PDCD5 (programmed cell death 5), NFIL3 (nuclear factor, interleukin 3 regulated protein), HSP90B1 (heat shock protein 90kDa beta (Grp94), member 1), VCAM1 (vascular cell adhesion molecule 1), IL1R1 (interleukin 1 receptor, type I), TNIP1 (TNFAIP3 interacting protein 1), JAK1 (Janus kinase 1), TNFAIP2 (tumor necrosis factor, alpha‐induced protein 2) IL6ST (interleukin 6 signal transducer (gp130, oncostatin M receptor)) CFD (complement factor D (adipsin) and PPARG (peroxisome proliferator‐activated receptor gamma) among others. These genes are responsible for inflammation, apoptosis, regulation of Toll‐like receptors in inflammatory response, leucocyte migration and fibrosis in chronic inflammation.

We present for the first time in the Nile crocodile, a comprehensive lists of inflammatory response genes that are expressed and up regulated in pansteatitis in the Nile crocodile.

Support or Funding Information

Part of the study was funded by Tertiary Education Trust Fund (TETFund) AST and D, Nigeria and Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
“The Role of the Unfolded Protein Response in Mediating Adaptations to Exercise Responsiveness”
Authors: Hart Corey R. , Koh Jin‐Ho , Dasari Surendra , Lalia Antigoni Z. , Lanza Ian R.
Published: June 2021

Aging is associated with altered mitochondrial physiology and exercise responsiveness in skeletal muscle. Activation of the unfolded protein response in the endoplasmic reticulum (UPRER) and mitochondria (UPRMT) is linked with exercise‐induced adaptations in skeletal muscle, but the possibility that these processes impact exercise responsiveness and mitochondrial function in older humans has not been fully elucidated. The purpose of this study was to evaluate age‐related changes in UPRER and UPRMT gene transcripts and protein abundance in response to a single bout of exercise. Muscle biopsies were obtained from 12 young (27±5 yr) and 12 older (75±5 yr) well‐matched, healthy men and women before exercise and 18h following a single bout of unilateral leg extension. Before exercise, a gene set enrichment analysis (GSEA) revealed that 27 genes associated with the UPRER were upregulated in the older subjects compared to the young (enrichment false discovery rate [FDR] = 0.0842). After exercise, GSEA indicated upregulated UPRER genes in both the young (FDR = 0.0405) and older subjects (FDR = 0.0619), however, pathway activation analysis revealed significantly greater activation of UPRER and UPRMT gene transcripts post‐exercise in the younger subjects (P < 0.05). In contrast, age did not affect key UPR‐regulatory protein abundance 18h post‐exercise. Interestingly, statistically significant correlations were observed in the young subjects between the mitochondrial transcriptional coactivator, peroxisome proliferator‐activated receptor gamma coactivator 1‐alpha (PGC‐1α) and key regulatory genes associated with the UPRER (GRP78, R = 0.67; ATF6, R = 0.70) and the UPRMT (HSPE1, R = 0.61; HSPD1, R = 0.55; and HSPA9, R = 0.79), which were not evident in the older subjects. In conclusion, transcriptomic analysis revealed an age‐related decline in the adaptive UPRER and UPRMT transcriptional response following a single bout of exercise that could potentially explain, in part, impaired exercise responsiveness and mitochondrial dysfunction with age.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Mechanisms of Gender Differences in Exercise Capacity
Authors: Oydanich Marko , Rynecki Nicole , Zhang Jie , Vatner Dorothy , Vatner Stephen
Published: June 2021

The examination of gender differences has been a recent priority of the NIH. It is well documented that female rodents exhibit higher exercise capacity than their male counterparts. We confirmed this in C57 wild‐type(WT) mice, where female mice exhibited greater, p<0.05, maximal exercise capacity for running distance (469 ± 24 m) than age‐matched male WT mice (337 ± 14 m). The first goal was to examine whether these differences persisted with models of enhanced exercise capacity, e.g. exercise training and the adenylyl cyclase type 5 knockout (AC5 KO) mouse. When WT mice underwent chronic exercise‐training, female mice maintained their superiority over males, with females running a 32% greater distance (p<0.05) than age‐matched trained males. However, AC5 KO mice, which demonstrated enhanced exercise capacity, did not exhibit a gender difference, with female AC5 KO mice (695 ± 51 m) running similar distances to male AC5 KO mice (661 ± 45 m). The next goal was to determine mechanisms mediating these differences. After ovariectomy, WT female mice no longer demonstrated enhanced exercise compared with males. Conversely, chronic administration of estrogen to male mice improved their exercise performance and eliminated the gender differences with exercise. Next we investigated nitric oxide (NO), a downstream target of estrogen. Total NO synthase (NOS) activity was higher in female mice compared with male mice in both sedentary (207 ± 14 U/mg vs. 138 ± 4 U/mg, p<0.05) and exercise trained groups (338 ± 42 vs. 193 ± 15 U/mg, p<0.05). Ovariectomized females exhibited nitric oxide levels similar to males (165 ± 11 U/mg). Administration of L‐NAME, resulting in NO blockade, eliminated the gender differences in exercise performance. In AC5 KO mice NOS activity was not different in male and female mice and similar exercise performance in males and females was still observed after treatment with L‐NAME. Thus, both estrogen and nitric oxide are key mechanisms mediating the enhanced exercise performance in female mice.

Support or Funding Information

This study was supported by the National Institute of Health grant R01HL106511

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Voluntary Exercise Modifies Olfactory Circuits in Control‐ and Fat‐Fed Mice
Authors: Chelette Brandon , Thomas Abigail , Giachos Danielle , Gonzalez Daniel , Vinson Margaret , Fadool Debra
Published: June 2021

Consumption of a fatty diet causes loss of olfactory sensory neurons (OSNs), loss of olfactory discrimination assessed by olfactometry and electroolfactogram, and increased inflammation in the olfactory epithelium. Because of potential anti‐inflammatory properties of voluntary exercise, we hypothesized it could mitigate the detrimental effects of a fatty diet on the olfactory system. Mice with reporters for the olfactroy receptor M72 (Olfr160) and those with resistance to diet‐induced obesity (Kv1.3−/−) were challenged with control (CF) vs. moderately‐high fat (MHF) diet for 6 months upon weaning, with (running wheel; RW) and without access (sedentary; SED) to a Med Associates vertical wireless running wheel and sensor. MHF/RW mice (n=10; mean 7 month body weight = 40.1 g) gained less body weight than MHF/SED (n=10; 33.3 g, p<0.001) and were able to clear plasma glucose as efficiently as CF/SED mice. Although mice of all treatment groups ran at the same velocity, those provided MHF diet (distance run/day = 11.2 km) increased running distance compared to both CF‐fed WT (n=10) and Kv1.3−/− (n=5) mice (6.85 km/day and 8.29 km/day respectively; p=0.02). Actogram analysis demonstrated that CF‐fed Kv1.3−/− and MHF/RW spend 20.2% and 28.3%, respectively, more time running and exhibit shorter pauses in running activity than CF/RW. Whole‐mount brain images were examined to evaluate M72 staining as quantified by the pixel density of the lateral glomerulus and projections. MHF/RW M72 pixel density was twice as much as MHF/SED mice, but CF/RW pixel density was 31.6% lower than that of CF/SED mice. Our results indicate that in addition to combating weight gain and glucose intolerance, voluntary exercise may reduce the detrimental effects of a MHF diet on olfaction, but exercise may also affect the olfactory system independent of diet composition.

Support or Funding Information

This was supported by NIH grant RO1 DC013080 from the NIDCD and a Dean's Arts and Sciences Scholarship in the Chemical Senses from FSU.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Impaired Oxygen Uptake Kinetics Related to Reduced Peripheral Oxygen Extraction in Heart Failure with Preserved Ejection Fraction
Authors: Hearon Christopher M. , Sarma Satyam , Dias Katrin A. , Hieda Michinari , Levine Benjamin D.
Published: June 2021

Background

The amount of time needed to increase oxygen utilization to sufficiently meet metabolic demand (V̇O2 kinetics) is impaired in heart failure (HF) with reduced ejection fraction, and is an independent predictor of HF mortality. However, it is not known if V̇O2 kinetics are slowed in heart HF patients with preserved ejection fraction (HFpEF). We tested the hypothesis that V̇O2 kinetics are slowed during submaximal exercise (equivalent to activities of daily living) in HFpEF patients, and that slower V̇O2 kinetics are related to impaired peripheral oxygen extraction.

Methods

Eighteen healthy controls (69±6 years, 10 females) and eighteen HFpEF patients (68±7 years, 10 females) were studied during submaximal (~30% predicted max) and peak treadmill exercise. Cardiac output (Qc, acetylene rebreathing), pulmonary oxygen uptake (V̇O2, Douglas bags), and arterial‐venous oxygen difference (a‐v O2 diff) were measured during exercise. Breath‐by‐breath V̇O2 uptake was measured continuously at the onset and throughout submaximal exercise, and V̇O2 kinetics quantified as the time needed to for V̇O2 to rise to ~63% of steady state V̇O2 (mean response time, MRT).

Results

During submaximal exercise, absolute oxygen demand was similar between groups (V̇O2: Control: 0.81±0.1, HFpEF: 0.85±0.2 L/min; P=0.54) however, HFpEF patients had substantially slowed V̇O2 kinetics (MRT: Control: 40.1±14.2, HFpEF: 65.4±27.7 s; P=0.002), and >50% greater accumulated oxygen deficit compared to controls (Control: 400±173, HFpEF: 693±392 mL; P=0.007). At peak exercise, HFpEF patients had lower relative V̇O2 (Control: 22.2±4.0, HFpEF: 14.6±3.1 mL/kg/min; P<0.001), preserved peak Qc (Control: 13.4±4.0, HFpEF: 13.9±3.5 L/min; P=0.68), and reduced peripheral oxygen extraction (a‐v O2 diff: Control: 12.7±2.9, HFpEF: 10.4±2.1 mL/dL; P=0.01). When stratified by MRT, HFpEF patients with a MRT >60s demonstrated impaired peripheral oxygen extraction that was apparent during submaximal exercise compared to HFpEF patients with a MRT <60s (submaximal a‐v O2 diff: MRT<60s: 9.7±2.1, MRT>60s: 7.9±1.1 mL/dL; P=0.03).

Conclusions

HFpEF patients have slowed V̇O2 kinetics during exercise that are due in part to impaired peripheral oxygen utilization. This finding supports growing evidence that peripheral oxidative capacity is a primary contributor to exercise intolerance in HFpEF leading to substantial oxygen deficit even during activities of daily living. Further, MRT can lend important insight into the pathophysiology of exercise intolerance in individual HFpEF patients, and identify patients with severe peripheral limitations to exercise capacity.

Support or Funding Information

NIH: AG017479, F32‐HL137285

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
The Exercise Pressor Reflex is attenuated and Coronary Exercise Hyperemia is improved by Peripheral Revascularization in Peripheral Arterial Disease
Authors: Miller Amanda Joy , Luck J Carter , Kim Danielle Jin‐Kwang , Leuenberger Urs A. , Aziz Faisal , Radtka John F. , Sinoway Lawrence I. , Muller Matthew D.
Published: June 2021

Patients with peripheral arterial disease (PAD) have a greater blood pressure (BP) response to exercise or augmented exercise pressor reflex. Our recent work showed that PAD patients also have impaired coronary blood flow responses to exercise which may increase cardiovascular risk. We investigated the effects of leg revascularization procedures on the BP and coronary blood flow responses to exercise in PAD. Seventeen PAD patients (11 men, 66 ± 2 yr) performed single‐leg plantar flexion exercise for up to 6 minutes twice: 24 hr before and one month following leg revascularization. BP and heart rate (HR) were measured continuously and rate pressure product (systolic BP × HR) was calculated as an index of myocardial oxygen demand. Coronary blood velocity was obtained by transthoracic Doppler echocardiography. The mean BP response to plantar flexion exercise was attenuated by leg revascularization (pre revascularization: 15 ± 4 vs. post revascularization: 7 ± 3 mmHg, P = 0.025). The HR response to plantar flexion was also attenuated following leg revascularization (pre revascularization: 9 ± 1 vs. post revascularization: 6 ± 1 beats/min, P = 0.006). The change in coronary blood velocity with exercise was significantly greater at the post revascularization visit: 4 ± 1 vs. pre revascularization: −1 ± 2 cm/s (P = 0.038). The rate pressure product response to exercise tended to be lower following revascularization but this did not reach statistical significance (pre revascularization: 2796 ± 871 vs. post revascularization: 1766 ± 378 mmHg*beats/minute, P = 0.082). These data suggest that leg revascularization improves reflex control of BP, HR, and coronary blood flow in response to exercise in patients with PAD.

Support or Funding Information

P01 HL134609 (Sinoway)

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Stimulation of Peripheral Opioid Receptors during Acute Exercise Decreases Anxiety‐Like Behaviors in a Rat Model of Fibromyalgia
Authors: Williams Emily R. , Daniels Abigale B. , Ford Caleb M. , Horton Molly , Stocks Silas , Leal Anna K.
Published: June 2021

Patients with fibromyalgia often experience comorbid anxiety. Studies show exercise training can decrease pain in patients with fibromyalgia as well as decrease anxiety in healthy populations. Evidence suggests endorphins acting on opioid receptors contribute to exercise‐induced analgesia, but the role of these receptors on anxiety has not been determined in patients with fibromyalgia. The purpose of this study was to compare the effects of sedentary behavior and exercise training on anxiety in a rat model of fibromyalgia and to determine the contribution of peripheral opioid receptors to the exercise‐induced response. Female Sprague Dawley rats were induced with fibromyalgia by acidic saline injections (0.1 mL; pH 4). To assess anxiety‐like behaviors, rats were placed in an open field arena (90 × 90 cm) for two minutes. The arena floor was marked with 20.5 cm grids and the number of grids crossed during the observation period was recorded: a decrease in grids crossed indicated increased anxiety. A group of sedentary rats (SED; n=8) were tested for anxiety 5 days/week for 4 weeks. Another group of treadmill‐trained rats (NAL; n=5) received injections of the nonspecific opioid receptor antagonist naloxone (120 μg in 0.1 mL saline) in both gastrocnemius muscles ten minutes prior to moderate‐intensity (15 m/sec) treadmill running (4 weeks; 5 days/week; 30 min/day). NAL rats were observed in the open field arena before (PRE) and after (POST) each running bout. Mean grids crossed for SED rats in the open field were 21.3 ± 2.4 for week 1, 23.7 ± 2.9 for week 2, 29.7 ± 2.9 for week 3, and 28.0 ± 3.0 for week 4. While NAL PRE grids crossed were not different from SED grids crossed, the POST grids crossed for NAL rats decreased for all weeks: 16.5 ± 2.0 (PRE) and 10.1 ± 1.9 (POST) for week 1, 24.0 ± 1.9 (PRE) and 12.4 ± 1.4 (POST) for week 2, 21.8 ± 1.9 (PRE) and 10.4 ± 1.7 (POST) for week 3, and 23.6 ± 2.2 (PRE) and 13.2 ± 1.8 (POST) for week 4 (all p<0.05). Further, NAL POST grids crossed were significantly different from SED grids crossed for weeks 1, 2, 3 and 4 (p<0.05). While our data does not show a long‐term effect of exercise training on anxiety, it does suggest that stimulation of peripheral opioid receptors during acute exercise decreases anxiety‐like behaviors in the rat model. In conclusion, this study provides evidence that peripheral, in addition to central, opioid receptors contribute to an exercise‐induced decrease in anxiety and that even one exercise bout is beneficial when compared to sedentary behavior.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Cerebral oxygenation in Metabolic Syndrome patients during mental task and muscle metaboreflex activation
Authors: roberto silvana , doneddu azzurra , pinna virginia , milia raffaele , ghiani giovanna , lecis romina , velluzzi fernanda , magnani sara , sainas gianmarco , guicciardi marco , crisafulli antonio
Published: June 2021

The post‐exercise muscle ischemia (PEMI) is a well established method to study the cardiovascular adjustments to exercise since it enhances sympathetic tone thereby recruiting the hemodynamic reserves. Thus, PEMI can reveal cardiovascular diseases1,2. Our hypothesis was that, in patients suffering from Metabolic Syndrome (MS), cerebral oxygenation decreased during the metaboreflex elicited by PEMI, because of an exaggerated sympathetic response which could vasoconstrict the cerebral circulation3. Furthermore, we hypothesized that in these patients, the cerebral oxygenation could be further impaired by superimposing a mental task (MT) to PEMI. To this aim, variation in cerebral circulation of MS patients was compared with that of healthy controls during contemporary PEMI and MT.

Two groups were enrolled: one composed of 15 subjects (7 women, age 53.5±10.7 yrs.) suffering from MS and a control group (CTL) composed of 14 healthy subjects (6 women, age 50.86±8.2 yrs). Both groups underwent 5 different tests each lasting 12 min: PEMI, control exercise recovery (CER), PEMI+MT, CER+MT, and MT alone. During each session, cerebral oxygenation (COx) was measured by Near Infrared Spectroscopy (NIRS) by applying sensors to the skin of the forehead.

Data analysis found no significant differences in COx between groups during any test. No reduction in COx were observed during the PEMI test (CTL 100.9±3.3% vs MS 102.5±1.9%) and the MT test (CTL 101.5±2.2% vs MS 102±1.8%) in both groups. Moreover, the addiction of MT to the PEMI test did not cause any impairment in COx.

Contrary to our hypothesis, results of the present study indicate that in patients with MS there is no impairment in COx during sympathetic activation obtained by PEMI. Furthermore, no significant reduction was found in the COx when adding MT to the PEMI test. It was concluded that COx is not impaired in patients suffering from MS when sympathetic tone is augmented.

Support or Funding Information

This study was supported by the “Fondazione di Sardegna”

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
The Association between Oxidized Low Density Lipoprotein Concentration and Paraoxonase‐1 Activity, Total Antioxidant Capacity, and Low Density Lipoprotein Concentration in Highly Trained Individuals
Authors: Robison Charles E. , Davis Paul G. , Goldfarb Allan , Mellick Paul
Published: June 2021

Physical fitness is associated with reduced risk factors for cardiovascular disease, in particular oxidized low‐density lipoprotein (ox‐LDL). Therefore determinants of ox‐LDL in fit individuals are important to understand. Antioxidant defenses and the concentration of low‐density lipoprotein (LDL) are associated with ox‐LDL concentration, however the relative importance of these variables is not fully understood. Paraoxonase 1 (PON1) is an antioxidant enzyme capable of preventing the oxidation of LDL. Moreover, total antioxidant capacity (TAC) is an assessment of the broad antioxidant status of the blood.

PURPOSE

Our purpose was to measure the association between ox‐LDL concentration and PON1 activity, TAC, and LDL concentration in highly trained individuals.

METHODS

Participants were instructed to refrain from exercise for 48 hours prior to blood sampling. Following a 12‐hour fast venous blood was taken at rest to determine ox‐LDL in plasma, PON1 in serum, and TAC in serum. LDL concentration was estimated using the Friedewald formula. Pearson Product Moment correlations were used to assess the relationships between ox‐LDL concentration and PON1 activity, ox‐LDL concentration and TAC, and ox‐LDL concentration and LDL concentration.

RESULTS

Fifteen individuals (12 males, 3 females) who had high cardiorespiratory fitness (VO2max= 54.8 ± 1.7 ml×kg−1×min−1) completed the study. We found no association between ox‐LDL concentration and PON1 activity (r= 0.08, p = 0.78) and no association between ox‐LDL concentration and TAC (r= −0.15, p= 0.58). However there was a significant association between ox‐LDL concentration and LDL concentration (r= 0.82, p < 0.001).

CONCLUSION

This indicates that in highly trained individuals LDL concentration may be more important than antioxidant defenses in the development of circulating ox‐LDL concentration.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Relationships between injury years and thermoregulatory responses during heat stress in spinal cord injury persons.
Authors: Kamijo Yoshi‐ichiro , Shibasaki Manabu , Kinoshita Tokio , Moriki Takashi , Nakamura Takeshi , Kouda Ken , Tajima Fumihiro
Published: June 2021

Thermoregulatory responses via sympathetic nerve activity during heat stress are absent or impaired in persons with spinal cord injury. However, relationships between their injury years and responses of sweating and cutaneous vasodilation to increased core temperature remained unknown. Six of cervical (CSCI; N=6; level of C5‐7; injury years of 1–22 yrs) and 8 thoraciolumbal (SCI; N=8; Th4‐L1; 1–24 yrs) spinal cord injury persons and 10 healthy subjects (AB; able‐body) were recruited. They wore water‐perfused suits with taking a supine position and 33‐degree C water was perfused into the suits to make a whole body thermoneutral condition, while all devices were applied. After 10‐min measurements during thermoneutral condition, heat stress was performed with infusion of 47‐degree C water until esophageal temperature (thermocouples) increased by 1 degree C. Mean arterial pressure (MAP; the brachial artery; Korotkoff's method), mean skin (Tsk) and local chest temperatures (Tchest; thermocouples), sweat rate (SR; capacitance hygrometry) and skin blood flow (SkBF; laser‐Doppler velocimetry) on the chest. Cutaneous vascular conductance (CVC) were calculated as SkBF divided by MAP. Tsk was about 35 degree C in all groups and increased by 3 degree C. Tchest increased by 1.4 degree C during heat stress. CVC increased by 4 times as baseline in AB, 3 times in SCI during heat stress, but no increase was observed in CSCI. Patterns of SR in all groups were similar to CVC. Maximal response of CVC [control/degrees] was tended to be negatively correlated, but that of SR [mg/cm2/min] was positively correlated with injury years. In conclusion, thermoregulatory responses to increased core temperature were absent in CSCI and impaired in SCI. In SCI, sweating response on the chest, where sympathetic nerve activity is intact, is possibly enhanced to compensate for reduced cutaneous vasodilation with increased injury year.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Prior Viral Illness Exacerbates the Severity of Lung Injury in a Mice Heat Stroke Model
Authors: Plamper Mark l. , Dineen Shauna M. , King Michelle A. , Leon Lisa R.
Published: June 2021

Heat Stroke (HS) is a common threatto both civilian and warfighter populations, however the mechanisms underlying tissueinjury are unknown. Acute respiratory distress syndrome (ARDS) is often seen with the adverse sequelae that follows HS, and correlates with mortality. Further, anecdotal evidence suggests that prior illness can increase the severity of multi‐organ injury in HS. To examine the effect of a recent viral illness on the severity of ARDS following HS, male C57BL/6J mice (body weight 23.0 ± 0.3g)were intraperitoneally injected with Polyinosinic: Polycytidylic acid (PIC; 100μg) or saline (SAL; 100 μl) 48‐h prior to heat exposure (HE; 39.5 ±0.1°C). Miceremained in HE until core temperature (Tc; ±0.1°C; radio telemetry) reached Tc Max of 42.4°C. Control mice were injected with saline or PIC, but never exposed to the heat. Lung tissue was collected for analysis of inflammatory biomarkers indicative of ARDS and cell death at Tc Max and at 1 day post HE (1d). Monocyte chemoattractant protein‐1 (MCP‐1; a predictor of ARDS severity) was upregulated in control mice injected with PIC alone (P=0.003 at Tc Max; P<0.001 at 1d)and HE exacerbated this response at both Tc Max and 1d (P<0.001 and P=0.029 respectively). Interestingly, eotaxin (an eosinophil‐specific chemoattractant)was suppressed at Tc Max following HE in both PIC and SAL groups (P<0.001). PIC in the absence of HE did not alter expression at Tc Max, however eotaxin was significantly upregulated in this group at 1d (P=0.041). To determine the extent of lung injury, a cell death assay was conducted. Unexpectedly, at Tc Max no differences in cell death were seen between groups; however, at 1d cell death was significantly augmented in those that received PIC alone (P=0.001) and those that received PIC prior to HE (P=0.002). In conclusion, PIC injection 48‐h prior to HE increases severity of lung tissue injury with the magnitude and time course of inflammatory changes was unique to each biomarker. Author views not official US Army or DOD policy.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Chemosensitive Cardiac Afferent Reflexes in Mice: Are they Altered in Hypertrophic Cardiomyopathy?
Authors: Larson Robert A. , Chapleau Mark W.
Published: June 2021

Hypertrophic cardiomyopathy (HCM) is a life‐threatening disease caused by sarcomere gene mutations. Hallmark features include myocyte disarray, left ventricular hypertrophy, fibrosis, and increased risk of arrhythmias and sudden death. Cardiac norepinephrine spillover is augmented in humans with HCM. Similarly, our group has previously reported that cardiac sympathetic tone is increased and vasomotor sympathetic tone is decreased in transgenic mice with cardiac‐specific expression of mutated alpha‐tropomyosin (Glu180Gly), a model of human HCM. Specific aims of this study were to develop protocols to evaluate cardiac reflexes evoked by activation of vagal and ‘sympathetic’ afferents in anesthetized mice, and test the hypothesis that alpha‐tropomyosin mutant HCM mice exhibit enhanced heart rate responses to activation of cardiac ‘sympathetic’ afferents. Cardiac reflexes were evoked via injection of the TRPV1 receptor agonist capsaicin (25 & 50 ng/g, IV) in mice anesthetized with ketamine (91μg/g) and xylazine (9.1 μg/g). Injection of capsaicin (50 ng/g, IV) in C57BL6 mice evoked rapid decreases in heart rate (HR) (−131±17bpm) and mean arterial pressure (MAP) (−30.1±2.7 mmHg) followed by delayed increases in HR (+12.5±7.6bpm) and MAP (+12.7±3.7 mmHg) (n=6, p<0.05). Responses were dose‐dependent and repeatable. Bilateral cervical vagotomy abolished the bradycardic/depressor responses to capsaicin and enhanced the delayed increases in HR (+22.6±4.1bpm) and MAP (+27.6±1.7 mmHg) (n=5). All responses to capsaicin were essentially abolished after ganglionic blockade (p<0.05, n=3) confirming the responses were neurally mediated. The tachycardic response to capsaicin (25ng/g, IV) after vagotomy was significantly (p<0.05) augmented in HCM mice (+32±11bpm, n=5) compared with their wild‐type (WT) controls (+11±3bpm, n=6). In contrast, the MAP response to capsaicin was similar between HCM (+8.5±2.5 mmHg, n=5) and WT (+6.3±1.6 mmHg, n=6). We conclude: (1) Measurements of reflex responses to capsaicin before and after vagotomy enable assessment of both inhibitory and excitatory reflexes in mice, and (2) HCM mice demonstrate an exaggerated tachycardic response to injection of capsaicin, presumably reflecting an increased sensitivity of cardiac ‘sympathetic’ afferent nerves.

Support or Funding Information

NIH T32HL007121, AAS‐Lundbeck Fellowship, NIH HL14388, VA 1BX001414

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Mechanisms of Cross‐Talk between Leptin and Angiotensin within the Arcuate Nucleus for the Control of Metabolic Rate
Authors: Sapouckey Sarah A. , Deng Guorui , Gibson‐Corley Katherine N. , Cui Huxing , Sebag Julien A. , Grobe Justin L.
Published: June 2021

Recent studies from our laboratory have demonstrated that within the arcuate nucleus of the hypothalamus (ARC), angiotensin II (ANG) type 1A receptors (AT1A) are expressed by the subset of neurons which express both the leptin receptor (LepR) and agouti‐related peptide (AgRP). AT1A expression in this subpopulation of AgRP neurons is critically involved in the integrative control of thermogenic adipose sympathetic nerve activity (SNA) and thereby resting metabolic rate (RMR) by various stimuli including leptin. It remains unclear, however, how LepR signaling results in AT1A activation within AgRP neurons. We hypothesize that activation of LepR (i) increases de novo synthesis of AGT and thus autocrine and/or paracrine ANG signaling within the ARC, and (ii) increases AT1A expression and trafficking to the cell membrane, increasing AgRP neuron sensitivity to ANG. Consistent with our first hypothesis, AGT is co‐localized within the ARC of C57BL/6J mice with cells expressing AgRP and LepR, as determined by fluorescent in situ hybridization and confocal microscopy. Studies of an immortalized mouse hypothalamic cell line (N43/5 cells, which exhibit a gene signature typical of AgRP cells) demonstrate that AGT mRNA is increased in response to leptin treatment. Selective genetic disruption of the AGT gene in LepR or AgRP neurons (AGTLepR‐KO and AGTAgRP‐KO mice) has no effect on energy flux under baseline chow‐fed conditions, though ongoing studies are focused on examining metabolic responses of these animals to high fat diet and leptin. Consistent with our second hypothesis, leptin application to N43/5 cells results in increased AT1A mRNA, and leptin injection in wildtype C57BL/6J mice increases AT1A mRNA in the ARC. Ongoing studies utilizing the new HiBiT‐tagging system (Promega) support cell surface localization of AT1A in the N43/5 cell line, which is increased by leptin treatment and reduced by ANG application. Ongoing studies are aimed at (i) examining the roles of pSTAT3, PI3K and ERK in the stimulation of AGT and AT1A expression by leptin, (ii) further characterizing AGTLepR‐KO and AGTAgRP‐KO mice by examining SNA and RMR in response to high fat diet and leptin, and (iii) using the HiBiT extracellular detection system to clarify the mechanism(s) by which leptin modulates cell surface localization of AT1A.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Spontaneous Baroreflex Control of Muscle Sympathetic Nerve Activity in Humans: Standardizing Analysis Procedures
Authors: Holwerda Seth W. , Carter Jason R. , Yang Huan , Pierce Gary L. , Fadel Paul J.
Published: June 2021

Beat‐to‐beat variations in muscle sympathetic nerve activity (MSNA) are strongly related to diastolic blood pressure (DBP) fluctuations, and the use of spontaneous occurring bursts of MSNA at rest to determine sympathetic baroreflex sensitivity has become more prevalent. However, published results using spontaneous sympathetic baroreflex sensitivity have lacked standard methodology for analysis. Indeed, there have been variations in the duration of the recording used, the size of the DBP bins (1‐, 2‐, 3‐mmHg), and strength of the linear regression r‐values accepted. Thus, we sought to comprehensively examine the influence of these varying analysis procedures on spontaneous sympathetic baroreflex sensitivity. Our goal was to provide a standardized procedure that would allow for consistent and comparable results across laboratories. In a collective group of subjects (n=150), weighted linear regression analysis between MSNA and DBP was performed with MSNA expressed as either burst incidence (bursts/100heartbeats) or total MSNA (summation of MSNA burst amplitude relative to number of cardiac cycles). Resting MSNA was analyzed over a 10‐min baseline period, and subsequently segregated into separate 5‐, 2‐, and 1‐min segments to examine the influence of baseline duration on the weighted linear regression. MSNA was averaged over 1‐, 2‐, or 3‐mmHg DBP ranges (bins) to examine the influence of bin size. Also, in a subset of subjects (n=35), the modified Oxford technique (intravenous infusion of sodium nitroprusside followed by phenylephrine) was performed for comparison. The average slope of the linear regressions for resting MSNA burst incidence and total MSNA progressively increased as the baseline duration decreased with 1‐min duration being significantly greater than 10 min (P<0.05); however, correlation coefficients were reduced with the shorter durations. Indeed, the 10‐min baseline durations most frequently yielded statistically significant probability values for linear regressions (P<0.05), which closely reflected the p‐values obtained during the modified Oxford. Interestingly, although bin size (1‐, 2‐, 3‐mmHg) had no major influence on the average slope of the regressions (P>0.05), correlation coefficients progressively increased with bin size such that the highest correlation coefficients were observed for the 3‐mmHg bin size for each time duration segment. Overall, the 10‐min durations and 3‐mmHg bin size yielded the highest correlation coefficients. Collectively, these findings suggest that the duration of the recording used for analysis impacts the statistical validity of the r‐values defining the slopes for spontaneous sympathetic baroreflex sensitivity, whereas larger bin size improves the r‐value but has less influence on the p‐value.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Augmentation of M‐Current and Increased Synaptic Efficacy at Intrinsic Cardiac Neurons Contributes to an Enhanced Cardiac Responsiveness to Vagal Nerve Stimulation in the Infarcted Porcine Heart
Authors: Tompkins John D. , Buckley Una , Salavatian Siamak , Shivkumar Kalyanam , Ardell Jeffrey
Published: June 2021

Imbalances to autonomic regulation of cardiac function contribute to risk for arrhythmia after myocardial infarction (MI). We tested the hearts responsiveness to vagal nerve stimulation (VNS), 8 wks after MI, to determine if parasympathetic control of the heart is altered in MI pigs. A significantly greater bradycardic response was elicited in MI animals during 20Hz stimulation. Intracellular voltage recordings from whole‐mount preparations of intrinsic cardiac neurons (ICNs) were subsequently used to assess whether alterations in neuronal membrane properties or synaptic transmission underlie the observed increase in responsiveness to VNS in MI animals. General membrane properties (resting membrane potential, input resistance, action potential amplitude/duration, afterhyperpolarization amplitude/duration) of ICNs from control and MI pigs were not different, but ICN excitability was significantly depressed in MI pigs. Testing synaptic efficacy revealed a greater proportion of strong (high AP probability) vs weak synapses (low AP probability) in MI animals. Tetanic stimulation (20Hz) of interganglionic nerve bundles elicited slow excitatory postsynaptic potentials (sEPSPs) in a significantly greater subset of MI ICNs (10/22) vs controls (4/26). The sEPSP persisted in hexamethonium (500uM) but was blocked by atropine (1uM), indicating mediation by cholinergic inhibition of M‐current. Application of 1mM Ba2+ increased excitability of ICNs from both control and MI animals further supporting a role for M‐current in the regulation of porcine ICN excitability. In hexamethonium, the amplitude of the sEPSP was significantly greater in MI ICNs. In conclusion, we identify a important role of M‐current in the regulation of the excitability of porcine ICNs, and demonstrate enhanced membrane depolarization of ICNs from MI animals after presynaptic stimulation due, in part, to greater inhibition of IM during tetanic nerve stimulation which may underlie the enhanced sensitivity to VNS in MI pigs.

Support or Funding Information

This work was supported in part by NIH grant OT2OD023848.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Copeptin Responses to Isotonic and Hypertonic Saline Infusion in Healthy Adults
Authors: Suh Hyun‐Gyu , Jansen Lisa T. , Sprong Cameron , Adams J.D. , Butts Cory L. , Seal Adam D. , Scott Dylan , Melander Olle , Lemetais Guillaume , Dolci Alberto , Vanhaecke Tiphaine , Perrier Erica T. , Kirkland Tracie , Kavouras Stavros A.
Published: June 2021

Copeptin, a c‐terminal segment of arginine vasopressin (AVP) prohormone, has equimolar secretion to AVP in response to osmotic, stress‐related, and hemodynamic stimulation. For this reason, and because of the difficulties in measuring AVP directly linked to its short half‐life, copeptin has been used as a stable and sensitive surrogate marker for AVP for various clinical indications. However, the plasma copeptin response to osmotic stimulation remains poorly documented.

PURPOSE

Examine the plasma copeptin response to plasma hyperosmolality induced by hypertonic saline infusion.

METHODS

Sixty healthy adults (50% male, age: 30±1 y, weight: 78.2±15.2 kg, body mass index: 26.9±4.0 kg·m−2) were infused intravenously with 3% (HYPER) or 0.9% (ISO) NaCl for 2 h (0.1 ml·kg−1·min−1) in a counterbalanced, cross‐over design. Blood samples were collected every 30 minutes. Plasma osmolality (POsm), copeptin (PCop; BRAHAMS copeptin proAVP, Thermo Fisher Scientific, Germany), and sodium (PNa) were measured, and changes in plasma volume (PV) were calculated from hematocrit and hemoglobin using the Dill & Costill equation.

RESULTS

Following the HYPER trial, PNa increased from 136±2 mmol ·L−1 to 146.5±3 mmol ·l−1 (P < 0.001), with PV expansion of 18.7±7.3% (P < 0.001). Both POsm and PCop increased significantly (0 min: 286±3 mmol·kg−1 and 4.5±3.7 pmol·L−1; 120 min: 305±4 mmol·kg−1 and 20.4±12.8 pmol·L−1, respectively, P < 0.001). Mean (95% CI) PCop increased with increasing POsm: 3.2 (2.5–3.8) pmol·L−1 for POsm ≤ 284.9 mmol·kg−1; 5.4 (3.8–7.0) pmol·L−1 for POsm 285–289.9; 6.2 (4.3–8.0) pmol·L−1 for POsm 290–294.9; 8.5 (7.1–9.9) pmol·L−1 for POsm 295–299.9; 12.3 (10.2–14.4) pmol·L−1 for POsm 300–304.9; and 19.2 (16.3–22.2) pmol·L−1 for POsm ≥ 305 mmol·kg−1. In contrast, during the ISO trial PNa remained unchanged during the 2‐h infusion (135.9±1.9 vs. 137.6±1.6 mmol·L−1), while PV expanded by 10.5±4.4% (P < 0.001 compared to baseline; P < 0.001 compared to HYPER). Neither POsm (0 min: 285±4,120 min: 287±3 mmol·kg−1) nor PCop (0 min: 4.1±1.8, 120 min: 3.8±3.0 pmol·L−1) were affected during the ISO trial.

CONCLUSION

Plasma copeptin was stimulated by increased plasma osmolality during a hypertonic infusion.

Support or Funding Information

This research was supported by Danone Research

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Synaptic Plasticity in the Dorsal Vagal Complex: Role in Salt Intake and Alteration by Estrogen
Authors: Toal Sheri L. , Curtis Kathleen S.
Published: June 2021

Sodium depletion produced by the natriuretic‐diuretic, furosemide (Furo) stimulates salt intake that increases progressively with repeated Furo treatments. Hormonal, osmotic, and neural signals regarding perturbations in sodium balance are initially processed within neurons and glia of the hindbrain dorsal vagal complex (DVC). Thus, plastic changes to glia and synaptic proteins can alter the effectiveness of synapses in the dorsal vagal complex to propagate signals to forebrain areas involved in body fluid regulation and thereby produce progressive increases in salt intake. Central actions of estrogen contribute to sex differences in a variety of adaptive behaviors, including salt intake in response to Furo treatment. Therefore, our objective was to assess the effect of estrogen on the expression of glial fibrillary acidic protein (GFAP; a marker for glia) and synaptotagmin 4 and calcium calmodulin kinase II (SYT4 CaMKII; synaptic proteins) in the DVC in response to repeated treatments with Furo. Adult female rats were ovariectomized, allowed to recover for 7 days, and then given estradiol benzoate (EB; 10 μg/0.1 ml oil, sc) or oil vehicle (OIL; 0.1 ml, sc) each week for 3 weeks. Rats were injected weekly with Furosemide (5 mg/kg, sc) or 0.15 M NaCl 18–24 hours after injection on week 1 and 2; and rats were also given 3‐hr access to one bottle of deionized water and one bottle of 0.5 M NaCl (salt) without food. On week 3, rats were terminated via decapitation 18–24 hours after the second injection, and the brains were flash frozen in liquid nitrogen, homogenized, and stored at −80°C. Frozen tissue punches from DVC were immunoblotted for GFAP (Millipore MAB360 mouse anti‐GFAP; 1:6000), CaMKII (Thermo Fisher MA1‐048 mouse anti‐CaMKII; 1:2000), synaptotagmin 4 (Thermo Fisher PA5‐52709 rabbit anti‐SYT4; 1:250), and β‐actin (#4970; Cell Signaling rabbit anti‐ β‐actin; 1:1000). Salt intake was increased in furosemide treated rats compared to isosaline treated rats independent of number of depletions. Estradiol produced a greater increase in salt intake compared to oil‐treated rats after first furosemide‐induced sodium depletion. Water intake was increased in furosemide treated rats compared to isosaline treated rats. Repeated furosemide treatment altered the expression of GFAP, SYT4, and CaMKII in the DVC. Preliminary analysis suggests estradiol may alter expression of GFAP, SYT4, and CaMKII in the DVC.

Support or Funding Information

Supported by OCAST HR12‐196

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Hypoxia Avoidance Behavior in two Air‐breathing Fishes
Authors: Jew Corey , Hicks James W.
Published: June 2021

Aquatic animals are known to be sensitive to low oxygen environments. Aquatic hypoxia can limit an animal's capacity for aerobic metabolism, reducing its ability for locomotion, growth, reproduction, and survival. It is thus important for a fish to be able to detect and avoid hypoxic environments or develop an auxiliary method for obtaining oxygen, such as breathing air. Air breathing allows a fish to access environments and maintain aerobic metabolism independent of environmental oxygen levels. In this study, we test two air‐breathing fishes, Polypterus and Pangasianodon, for the presence of a hypoxia avoidance behavior both when allowed to freely breathe air and when air access is denied. Fish were placed in a shuttle box consisting of two circular arena attached to allow free movement between the two. A fish was placed in the shuttle box and monitored as oxygen was reduced on one arena and then returned to normal while the other side was reduced. Separate trials were run with a subsurface net to deny air breathing. Polypterus did not show a hypoxia avoidance behavior when allowed air access, however it did when denied air access, similar to a solely water‐breathing fish. Pangasianodon did not show a hypoxia avoidance behavior with or without air access even at oxygen levels below its air‐breathing threshold and Pcrit. Pangasianodon has been shown to survive beyond 25 h below its Pcrit without air access, suggesting that this animal maintains physiological mechanisms for hypoxia tolerance (e.g., metabolic suppression) not present in other air‐breathing fishes, such as Polypterus. Further studies will compare the ability of Polypterus and Pangasianodon to reduce metabolism in response aquatic hypoxia.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.