bluuebunny/crossref_metadata_2025 huggingface dataset:
Inhibition of ERK phosphorylation decreases post‐stress avoidance in high stress reactive rats
Authors: Whitaker Annie , Gilpin Nicholas
Published: November 2023

Avoidance is a primary symptom of post‐traumatic stress disorder (PTSD). Our laboratory has established a rodent model of traumatic stress that mimics the avoidance symptom cluster of PTSD. Animals are classified as ‘Avoiders’ or Non‐Avoiders’ post‐stress based on avoidance of predator‐odor paired context. Previously we have demonstrated that Avoiders exhibit differences in neuronal activation patterns associated with re‐exposure to traumatic stress‐related stimuli. The central amygdala (CeA) is a brain region important for mediating emotional responses and fear. Humans with PTSD exhibit amygdalar hyperactivity in response to stimuli associated with their traumatic experiences. The aim of these studies was to examine the effects of traumatic stress on CeA neuronal activation as measured by increases in ERK phosphorylation and the role of ERK phosphorylation in mediating stress‐induced avoidance. Male Wistar rats (275g) were exposed to predator odor (bobcat urine) paired with context and were 1) sacrificed from home cage or re‐exposed to context prior to sacrifice for examination of ERK phosphorylation in the CeA or 2) infused with either vehicle or the ERK inhibitor (U0126; 1ug/0.5ul/side) and re‐tested for avoidance of the predator odor‐paired context. Re‐exposure to the predator‐odor paired context produced an increase in ERK phosphorylation in the CeA of Avoider rats relative to Non‐Avoider rats (2.69±0.76 vs. 1.44±0.46; p=NS). Furthermore, pre‐treatment with U0126 decreased avoidance compared to vehicle treated Avoider rats. These data provide insight into the neural mechanisms mediating stress‐induced avoidance.

Support or Funding Information

This work was supported by NIH grants: AA018400 (NWG), AA023305 (NWG).
High Fat Diet (HFD) Induced Inhibition of Sympathetic Outflow to Brown Adipose Tissue (BAT): Role of the Nucleus Tractus Solitarius (NTS)
Authors: Madden Christopher J , Morrison Shaun F
Published: November 2023

The lack of radio labeled glucose uptake in BAT in obese humans has been interpreted to suggest that these individuals lack significant depots of active BAT. This seemingly contradicts the observation in rodent models of diet‐induced obesity that BAT (UCP‐1 expression) is upregulated, a state that is typically associated with increased activity of BAT. In the current studies rats made obese by maintenance on a HFD failed to increase BAT sympathetic nerve activity (SNA) in response to cooling. In contrast, mRNA for UCP‐1 was up regulated by a HFD. In addition, activation of the sympathetic premotor neurons in the raphe pallidus with the GABAA receptor antagonist, bicuculline, increased BAT SNA and thermogenesis in both rats maintained on a HFD and those on control diet; suggesting that the sympathetic pathway from the level of the sympathetic premotor neurons to the BAT is not impaired in rats maintained on a HFD. Stimulation of vagal afferent activity or activation of neurons in the NTS (the site of vagal afferent terminals) inhibits cooling‐evoked sympathetic outflow to BAT, therefore this study also sought to test whether glutamatergic activation of neurons in the NTS plays a role in HFD‐induced inhibition of BAT SNA. Blockade of glutamatergic receptors in the NTS reversed the HFD‐induced inhibition of BAT SNA and thermogenesis. Finally, lipid metabolites that may be altered in animals on a high fat diet act on TRPV‐1 receptors in the NTS to enhance glutamatergic neurotransmission. The current study investigated whether activation of TRPV‐1 receptors in the NTS also play a role in the HFD‐induced inhibition of BAT SNA. Blockade of TRPV‐1 receptors in the NTS reversed the HFD‐induced impairment of cooling‐evoked BAT SNA. These data suggest that plasticity in the NTS during maintenance on a HFD may contribute to weight gain by impairing metabolism in adipose tissue.

Support or Funding Information

Supported by American Diabetes Association Basic Science grant #1‐13‐BS‐120 and NIH R01 NS091066.
Does Acute Heat Stress Differentially‐Modulate RVLM Gene Expression of Ionotropic Neurotransmitter Receptors in Young and Aged F344 Rats?
Authors: Pawar Hitesh N , Balivada Shivasai , Montgomery Shawnee , Kenney Michael J
Published: November 2023

The rostral ventrolateral medulla (RVLM) is involved in the regulation of sympathetic nerve discharge (SND) and arterial blood pressure. Acute hyperthermia produces marked activation of visceral SND in young rats, and the functional integrity of this brainstem region is crucial for sustaining visceral sympathoexcitation to increased internal body temperature (Tc). Visceral SND responses to increased Tc are attenuated in aged compared with young F344 rats, and central mechanisms contributing to age‐associated alterations in SND responses to hyperthermia are not well‐established. The balance between excitatory and inhibitory inputs, mediated primarily by glutamate and GABA neural systems, is important for regulating RVLM neuronal activity. In the present study we hypothesized that, in response to acute hyperthermia, the RVLM gene expression of various excitatory and inhibitory ionotropic neurotransmitter receptors would demonstrate age‐related differences. Tc was increased from 38°C to 41.5°C in young (3–4 months) and aged (23–24 months) anesthetized F344 rats. Total RNA was extracted from RVLM‐containing micropunches and gene expression analysis for ionotropic neurotransmitter receptor subunits was performed using TaqMan real time RT‐PCR. Gene expression levels of glutamate, GABA and glycine neurotransmitter binding receptor subunits were compared between age groups. Gene expression analysis revealed an upregulation in some, but not all, major excitatory NMDA and AMPA neurotransmitter receptor subunits in young compared with aged rats. In addition, major subunits of the inhibitory GABA and glycine receptors demonstrated substantial upregulation in aged compared with young rats. These preliminary data suggest that, in response to acute hyperthermia, aging modulates the functional balance of RVLM excitatory and inhibitory neurotransmitter receptor subunits.

Support or Funding Information

NIH AG‐041948.
Decrease in afferent evoked glutamate release in the rat NTS in chronic heart failure
Authors: Mastitskaya Svetlana , Gourine Alexander , Ramage Andrew G
Published: November 2023

Homeostatic mechanisms maintain arterial blood pressure, blood volume and arterial blood gases within a narrow physiological range. One of the important sites in the brain involved in this regulation is the nucleus tractus solitarii (NTS) which receives afferent information from baroreceptors, cardiopulmonary and chemoreceptors. The major transmitter involved is considered to be glutamate (Baude et al 2009, J Chem Neuroanat 38, 145–153), which is released into the NTS when these cardiovascular/visceral afferents are activated. The present study was carried to determine if this release of glutamate from cardiovascular afferents can be detected using glutamate biosensors (Sarissaprobes®) and whether it is altered in heart failure. Heart failure was induced under anaesthesia by ligation of the coronary artery (Pfeffer et al., 1979, Circ Res. 44:503–512). Rats with chronic heart failure (5–6 weeks post‐infarction; infarct size between 30–40 %) or sham‐operated were then anaesthetized with α‐chloralose (100 mg/kg; i.v), neuromuscular blocked and artificially ventilated and the biosensor placed in the NTS. Cardiopulmonary afferents were activated by phenylbiguanide (PBG; 20μg per animal i.a.) and the depressor reflex (baroreceptor activation) by i.v. injection of norepinephrine (0.5 μg/kg). Cardiopulmonary and depressor reflex activation in sham‐operated rats caused a detected release of glutamate in the NTS of 2.6 ± 0.8 μM (n=10) and 1.1 ± 0.2 μM (n=10) respectively. In the case of cardiopulmonary reflex, this was associated with a decrease in MAP of 42 ± 7 mmHg and HR of 99 ± 20 bpm, while for the depressor reflex there was an increase in MAP of 37 ± 5 mmHg and a decrease in HR of 21 ± 8 bpm. In rats with heart failure, although there was no significant difference in the cardiovascular effects caused by activation of these reflexes, the amount of glutamate detected was significantly (P<0.001) reduced to 0.5 ± 0.3 μM (n=6) and 0.2 ± 0.1 μM (n=6) respectively. Resting MAP and HR were similar in both groups. Thus in heart failure there is an approximate reduction of 80% in the glutamate being released by these afferents. This large decrease in the amount of detected glutamate overflow within the NTS in chronic heart failure could indicate a reduction in “spare capacity” in such transmission, although there is still enough to enable a “normal” reflex responses. It is possible that other transmitters may have also come into play to help maintain these reflexes in heart failure.

Support or Funding Information

British Heart Foundation project grant No PG/13/79/30429
Does trait anxiety influence muscle sympathetic nerve activity responsiveness in humans?
Authors: Carter Jason R , Fonkoue Ida T
Published: November 2023

The relationship between anxiety and muscle sympathetic nerve activity (MSNA) remains equivocal. The purpose of this study was to examine associations between trait anxiety and MSNA in young, healthy adults. We hypothesized that trait anxiety would be positively correlated to resting MSNA and MSNA reactivity to mental stress. Twenty adults (11 men, 9 women; 22±1 years; 24±1 kg/m2) were examined during a 10 min supine baseline and 5 min of mental stress (via mental arithmetic). Psychological measurement included trait anxiety determined using the State‐Trait Anxiety Inventory (STAI), and autonomic measurements included blood pressure (sphygmomanometer and finger plethysomography), heart rate (HR; electrocardiogram), and MSNA (micro neurography). Standardized trait anxiety was 43±2 arbitrary units (range 30 – 57; n=20), while mean baseline values of mean arterial pressure (MAP; n=20), HR (n=20), and MSNA (n=13) were 77±2 mmHg, 68±3 beats/min, and 11±1 bursts/min, respectively. Mental stress significantly (p<0.05) increased MAP (Δ7±1 mmHg; n=20), HR (Δ15±2 beats/min n=20), and MSNA (Δ2±1 burst/min; n=10). Trait anxiety was not correlated with resting MAP (r=−0.053, p=0.824), HR (r=0.193; p=0.415), MSNA burst frequency (r=−0.158; p=0.605), or MSNA burst incidence (r=−0.147; p=0.632). MAP (r=0.311; p=0.182) and HR (r=0.047; p=0.876) reactivity to mental stress were not correlated with trait anxiety. In contrast, trait anxiety was strongly correlated with MSNA reactivity to mental stress quantified as changes (Δ) in MSNA burst frequency (r=−0.742; p=0.014), Δ MSNA burst incidence (r=−0.750; p=0.013), and % change in total MSNA (r=−0.700; p=0.024). Contrary to our initial hypothesis, the associations between trait anxiety and MSNA reactivity to mental stress were negative. In conclusion, this pilot study suggests a negative association between trait anxiety and MSNA reactivity to mental stress. Our findings advocate for the inclusion of basic psychological surveys such as STAI prior to micro neurographic sessions, and we posit that future studies might pool data across various laboratories to more definitively determine the role of psychological states and traits on sympathetic neural activity and reactivity in humans.

Support or Funding Information

Support from NIH (HL‐122919).
Effects of angiotensin II receptor type 2 (AT2R) modulation on fear memory in a mouse model of Posttraumatic Stress Disorder (PTSD)
Authors: Swiercz Adam P , Wiaderkiewicz Jan P , Moshfegh Cassandra , Hopkins Lauren , Marvar Paul J
Published: November 2023

While the most widely known function of renin angiotensin system (RAS) is related to cardiovascular regulation, evidence also suggests an important role of RAS in the response to emotional stress. Our previous studies in a mouse model of PTSD have shown that peripheral AT1R inhibition with losartan increases the extinction (learned inhibition) of a traumatic fear memory and this affects brain AT1R mRNA expression. Therefore the purpose of this study was to further investigate brain RAS in the consolidation of fear memory. We performed classical Pavlovian fear conditioning in mice pairing auditory cues with foot shocks and examined mRNA expression of components of brain RAS and examined fear extinction behavior (% freezing to conditioned stimulus). Following the acquisition of fear, there was a 5 fold and 3 fold increase (*p <0.05, n=6) in mRNA expression of AT2R and angiotensin converting enzyme 2 (ACE2) in the central amygdala (CeA) and bed nucleus stria terminalis (BNST), regions involved in the consolidation of fear memory. However, mRNA expressions of the classical RAS pathway (AT1R and ACE) were unaltered in these brain regions. Thus we examined the effect of AT2R on long‐term fear memory. Mice received intraparietal (IP) or intracerebral (ICV) injections of either the novel non‐peptide AT2R‐agonist, Compound 21 (C21), or AT2R antagonist PD123,319 (PD) during classical Pavlovian fear conditioning. Twenty‐four hours following fear conditioning both C21 (10 mg/kg IP or 2μg/kg ICV) and PD (15 mg/kg IP or 200 μg/kg ICV) had no effect on extinction of fear memory compared to the vehicle. However, when fear memory retention was tested, the ICV C21 treated mice exhibited a trend for decreased freezing (C21 – 38%) (t(15) = 1.7; p = 0.1) versus saline (55%) and PD (64%) injected animals. These data suggest that brain AT2Rs and ACE2 may play a role in fear memory formation and / or retrieval.

Support or Funding Information

NIH R00 HL107675‐03
Chronic Endurance Exercise Training Preserves Contraction‐Induced Rapid Vasodilation in Older Adults
Authors: Hughes William E. , Ganger Charles T. , Ueda Kenichi , Casey Darren P.
Published: November 2023

Aging is associated with attenuated exercise hyperemia and vasodilation after a single skeletal muscle contraction, as well as during steady state exercise. Chronic exercise training preserves exercise hyperemia and vasodilation in older adults during steady‐state exercise; however, whether chronic exercise training ameliorates the attenuated rapid vasodilator response to a single skeletal muscle contraction in older adults is currently unknown. Therefore, the purpose of this study was to examine the impact of chronic exercise training on rapid vasodilator responses in older adults, as well as investigate the relationship between exercise capacity (VO2peak) and peak vasodilator responses (ΔVCpeak). Young (n = 14; 23±1yr; 9M/5F), older untrained (n = 16; 66±1yr; 10M/6F) and trained older adults (n = 16; 66±2yr; 9M/7F) performed single muscle contractions in the forearm (10%, 20%, and 40% MVC) and leg (20%, 40%, 60% WRmax). Blood flow (ml·min−1) was measured using Doppler ultrasound and vascular conductance was calculated from blood flow and mean arterial pressure (mmHg) and normalized for muscle mass (kg). The peak and total hyperemic and vasodilator responses were greater in trained older adults across leg exercise intensities compared to untrained older adults (P < 0.05), while there were no differences in responses between trained older and young adults (P > 0.05). Within arm intensities, trained older adults exhibited higher ΔVCtotal at 10%, and ΔVCpeak at 40% compared to untrained older adults (P < 0.05).There were no differences for rapid hyperemic and vasodilator responses between trained older adults and young adults at any arm exercise intensity (P > 0.05). VO2peak was moderately associated with ΔVCpeak at moderate and higher leg exercise intensities in older adults (r = 0.46 and 0.55 respectively; P < 0.01) but only at higher exercise intensities in young adults (r = 0.60; P < 0.05). Within the arm, VO2peak was moderately associated with ΔVCpeak across exercise intensities in older adults (10% r = 0.37, 20% r = 0.36, 40% r = 0.36; P < 0.05 for all), but not in young adults (r = −0.062–0.10; P > 0.05). When separated by training status, there were no associations between VO2peak and ΔVCpeak in the arm or leg (P > 0.05). Our data demonstrate that 1) chronic endurance exercise training preserves rapid hyperemic and vasodilator responses within both the arm and leg of trained older adults, such that age related differences in the rapid vasodilator response are abolished; and 2) VO2peak is moderately associated with peak vasodilator responses in the arm and leg of older, but not young adults.

Support or Funding Information

Funded by NIH HL‐105467 (DPC) and NIH CTSA U54TR001356
Changes in muscular strength, balance, and body composition in middle‐aged women with power yoga
Authors: Jin Haeng Mi , Kim Soo Yun , Moon Hwasil
Published: November 2023

The purpose of this study was to investigate the effect of power yoga on muscular strength, balance, and body composition in middle‐aged women. A total of 12 middle‐aged (43.6 ± 8.8 years, mean±SD) participated in the power yoga program during 12 weeks, 3 times per week, and 60 minutes each time. Muscular strength, balance, and body composition before and after power yoga program were measured. After power yoga program, subjects showed increased muscle strength including grip strength (25.4 ± 3.8 vs. 26.7 ± 3.3 kg) and back strength (57.6 ± 19.5 vs. 68.7 ± 20.6 kg). Balance was assessed with open and closed eyes and both were improved after power yoga (open eyes: 69.6 ± 36.2 vs. 97.6 ± 34.7 sec; closed eyes: 11.3 ± 9.8 vs. 22.4 ± 11.1 sec). Performing power yoga also improved body composition by decreasing % body fat (26.3 ± 4.9 vs. 23.1 ± 5.7) and increasing muscular weigh of legs (right leg: 6.0 ± 0.7 vs. 6.7 ± 0.7 kg; left leg: 6.0 ± 0.7 vs. 6.6 ± 0.7 kg). However, no differences were observed in body mass and waist circumference between before and after power yoga program. In summary, performing power yoga improved muscular strength, balance, and body composition in middle‐aged women. Therefore, power yoga program may be considered as a beneficial exercise strategy to improve health status of middle‐aged women by enhancing physical strength and body composition.
Cold fluid ingestion extends exercise capacity of heat‐sensitive individuals with Multiple Sclerosis in a warm environment
Authors: Chaseling Georgia K , Filingeri Davide , Hoang Phu , Barnett Michael , Davis Scott L , Jay Ollie
Published: November 2023

Exposure to a hot environment or heat gained during exercise can elicit a transient worsening of clinical symptoms in person with multiple sclerosis (MS), a demyelinating disease of the central nervous system). Heat‐related fatigue has been reported in 60–80% of individuals with MS, potentially limiting physical activity. Therefore, simple interventions that mitigate heat‐related reductions in exercise capacity in persons with MS are needed. Our aim was to test the hypothesis that cold fluid ingestion prolongs exercise duration of individuals with relapsing‐remitting MS cycling in a warm (30°C, 35% RH) environment. On two randomized occasions, 7 participants (54 ± 7 y; 76.1 ± 10.9 kg; 1.71 ± 0.09 m) diagnosed with relapsing‐remitting MS exercised at a low intensity (heat production: 3.2 ± 0.5 W·kg−1) for a maximum of 60 min (or until exhaustion), while ingesting a 3.2 mL·kg−1 aliquot every 15 min of either cold (1.5°C: CLD) or thermoneutral (37°C: NEU) water. Rectal (Tre) and mean skin (Tsk) temperature was continuously measured. Exercise duration was significantly longer (P=0.05) in the CLD trial (54.3 ± 11.0 min) compared to the NEU trial (46.4 ± 14.1 min). Indeed, after 45‐min of exercise, 3 of 7 participants remained in NEU, whereas 6 of 7 participants remained in CLD. All subjects were able to complete a minimum of 31 minutes of exercise. At this time point, absolute Tre (CLD: 37.08 ± 0.34°C, NEU: 36.99 ± 0.26°C; P = 0.59), the change in Tre (CLD: 0.25 ± 0.30°C, NEU: 0.25 ± 0.15°C; P =0.99), absolute Tsk (CLD: 34.41 ± 0.45°C, NEU: 34.31 ± 0.30°C; P = 0.57), and the change in Tsk (CLD: 1.35 ± 0.54°C, NEU: 1.41 ± 0.53°C; P = 0.63) were all similar between CLD and NEU. Additionally, at the termination end‐point of exercise, absolute Tre (CLD: 37.23 ± 0.30°C, NEU: 37.20 ± 0.26°C; P = 0.82), the change in Tre (CLD: 0.32 ± 0.30°C, NEU: 0.45 ± 0.18°C; P =0.70), absolute Tsk (CLD: 34.81 ± 0.27°C, NEU: 34.61 ± 0.35°C; P = 0.15), and the change in Tsk (CLD: 1.75 ± 0.85°C, NEU: 1.68 ± 0.88°C; P = 0.72) were all similar between CLD and NEU. In conclusion, during physical activity in a warm environment, heat‐sensitive individuals with MS exercised for longer before exhaustion with the ingestion of a cold compared to a thermoneutral fluid.

Support or Funding Information

This study was supported by a MS Research Australia Incubator Grant (Holders: Jay, Barnett, Hoang and Davis) and a University of Sydney International Collaboration Research Award (IRCA) (Holders: Davis and Jay). Dr Filingeri was supported by a Government of Australia Endeavour Fellowship
Isolating the independent effect of decreasing mean skin temperature on local thermal sensitivity of human hands and feet during cold stress
Authors: Filingeri Davide , Morris Nathan B , Jay Ollie
Published: November 2023

Whether reductions in whole‐body mean skin temperature (Tsk), with no concurrent changes in core temperature (Tc), alter local thermal sensitivity (TS) of human skin is currently unknown. On 4 separate occasions, 8 males (27±5y) underwent a 30‐min whole‐body cooling protocol (water‐perfused suit: ~5°C), during which a quantitative thermo‐sensory test, consisting of reporting (visual analogue scale) perceived magnitude of local warm (38°C) and cold (22°C) thermal stimuli (25‐cm2 thermal probe) applied to hand (palm/dorsum) and foot (sole/dorsum), was performed before cooling and every 10min thereafter. The cooling protocol resulted in large progressive reductions in Tsk (10min: −3.36±0.67°C; 20min: −5.21±1.00°C; 30min: −6.32±1.14°C; p<0.001), with minimal changes in Tc (10min: −0.08±0.04°C; 20min: −0.07±0.07°C; 30min: −0.07±0.09°C; p<0.001). While no differences in TS to the local cold stimulus were observed for any skin region at any stage of the cooling protocol (ΔTS from baseline; 10min: −2.05±5.9%; 20min: −0.3±7.8%; 30min: −1.1±8.5%; p=0.790), a significant and progressive increase in warm TS occurred at each level of Tsk for all skin regions (10min: +4.9±7.5; 20 min: +6.1±4.5; 30 min: +7.9±6.1%; p=0.004). A significant association between decreasing levels of Tsk and increases in warm TS was observed (y= −1.217x+0.2139; R2=0.98; p=0.003), indicating a 1.4% increase in warm TS per 1°C drop in whole‐body Tsk. Overall, the same local warm stimulus (hence same increase in skin temperature) was perceived to be warmer with progressive reductions in whole‐body Tsk, indicating that, independently of Tc, decreases in whole‐body Tsk significantly alter local warmth, but not cold, TS of human hands and feet.

Support or Funding Information

Mr Morris was supported by a University of Sydney International Postgraduate Research Scholarship (IPRS). Dr Filingeri was supported by a Government of Australia Endeavour Fellowship
Effects of Modest Weight Gain on Estrogens in Healthy Men
Authors: Singh Prachi , Covassin Naima , Sert‐Kuniyoshi Fatima H , Romero‐Corral Abel , Davison Diane , Singh Ravinder J. , Jensen Michael D. , Somers Virend K
Published: November 2023

Background

Decreases in estrogen are shown to increase body fat in men. However, obese men have high levels of estrogen and the effects of weight gain on estrogen have not been previously investigated. The objective of this study was to investigate the relationship between regional fat depots and estrogen during modest weight in healthy men.

Methods

We investigated the effects of overfeeding in 25 healthy men (30 ± 7 years, 24.7 ± 3.1 kg/m2). Changes in regional fat depot during weight gain were assessed using dual‐energy X‐ray absorptiometry and abdominal computed tomography scans. Participants gained approximately 5% body weight in 8 weeks. Estrone (E1), 17β‐estradiol (E2) and sex hormone binding globulin (SHBG) were measured at baseline and after weight gain.

Results

Overfeeding was accompanied by 3.9 ± 1.3 kg weight gain. These increases in weight resulted from increases in total body fat mass (18.3 ± 8.5 vs. 21.7 ± 8.8 kg, p<0.001) while the fat free mass did not change (58.4 ± 8.6 vs. 58.9 ± 8.7 kg, p=0.15). E1 (32.28 ± 14.25 vs. 33.44 ± 12.29 pg/mL, p=0.56) and E2 (25.04 ± 8.3 vs. 26.52 ± 7.8 pg/mL, p=0.28) did not change after weight gain. However, weight gain resulted in decreased SHBG (22.8 ± 10.5 vs. 20.8 ± 11.1 nmol/l, p=0.036) and increased E2/SHBG ratio (1.4 ± 1.0 vs 1.63 ± 1.0, p=0.027). The changes in E2/SHBG ratio, a surrogate marker of bioavailable E2, was positively associated with increases in abdominal fat mass (p=0.048, rho=0.39) and increases in visceral fat mass (p=0.049, rho=0.39).

Conclusion

Modest weight gain in healthy men does not alter circulating E1 and E2 levels. However weight gain results in decreased SHBG and increased free E2 (E2/SHBG ratio). The increased E2/SHBG ratio suggesting a pro‐estrogen effect is associated with increases in visceral fat mass during weight gain. Our study therefore suggests a complex relationship between abdominal fat gain and free E2 in men which may conceivably predispose to feminizing characteristics in obese men.

Support or Funding Information

PS is supported by AHA Grant 11SDG7260046 and NIH grant DK81014. NC is supported by AHA grant AHA 13POST16420009. MDJ is supported by NIH grants DK45343 and DK40484. VKS is supported by NIH Grants HL73211, and DK81014. This study was made possible by a grant from NCRR (1UL1 RR024150).
SECRETORY FACTORS PRODUCED BY STROMAL CULTURES OF HUMAN OMENTAL ADIPOSE TISSUE INHIBIT ADIPOSE DIFFERENTIATION
Authors: Pickering R Taylor , Lee Mi‐Jeong , Jager Michal , Layne Matthew , Fried Susan K
Published: November 2023

The size of visceral adipose tissues (VAT) is associated with risk for metabolic disease. As compared to subcutaneous, VATs have a limited capacity to expand by hyperplasia, leading to adipocyte hypertrophy, inflammation and tissue dysfunction. In contrast to adipose stem cells (ASCs) derived from the stromal fraction of human abdominal subcutaneous (Abdsc) adipose tissue, the visceral (omental (Om)) ASCs differentiate very poorly (on average only ~30% vs ~90%). We wanted to test the hypothesis that Om adipose tissue secretes factors that inhibit differentiation of human adipose progenitor cells. We differentiated the ASCs isolated from Abdsc tissue in a standard cocktail with 50% conditioned media (CM) from paired samples (n=8) of Om and Abdsc adipose tissue (7 Females, 1 Male BMI > 35), 25% CM from paired samples of ASCs (n=13) or control media throughout the 14d of differentiation. Differentiation was determined by triglyceride accumulation. IL‐6, Activin A, and TGFB levels were measured by ELISA, Western blot, and PAI‐1 Luciferase reporter assay, respectively. Omental tissue CM reduced differentiation to a greater extent compared to Abdsc [51±6 (Om) vs 111±12 (Absc) vs. control (171 mgTG/mgDNA)]. CM from Om ASCs suppressed differentiation more than CM from Abdsc [46±10 (Om) vs 26±5 (Sc) %suppression, n=13, p<0.05) and the magnitude of the effect correlated with the capacity of donors cells to differentiate (R2=0.4, p<0.01, n=17). As expected IL‐6 concentrations were much higher in CM from Om tissue and ASCs, but addition of IL‐6 did not inhibit differentiation. Members of the TGFB family, such as activin A and TGFB, are known inhibitors of adipogenesis, and we found that they were more highly expressed in Om ASCs. The concentration of activin A (0.9±0.2 AU vs 0.4±0.1 AU, n=9, p<0.05) and TGFB (1138±130 vs 539±65 AU n=13, p<0.001) were enriched in Om ASC conditioned media. Collectively, these data suggest that paracrine and autocrine production of TGFB and activin A, among other factors, produced by Om adipose tissue limit healthy adipose expansion and remodeling of human visceral adipose tissues.
The viability and differentiation of fetal spinal cord tissue after transplantation in injured mid‐cervical spinal cord
Authors: Lin Chia‐Ching , Lee Kun‐Ze
Published: November 2023

Mid‐cervical spinal cord injury interrupts the bulbospinal respiratory pathway and causes a secondary degenerative cascade, including loss of neurons and demyelination. To date, there is no effective treatment for spinal cord injury. Fetal spinal cord (FSC) tissue is composed of neural progenitors, which may have the capability to replace the lost cell and form a neural relay between separated spinal segments. Thus, the present study was design to investigate the viability and differentiation of progenitors derived from FSC after delayed transplantation into the injured spinal cord. Embryonic day 14 FSC expressing green fluorescence protein (GFP) was transplanted into the lesion cavity in rats received unilateral C4 hemisection at 1 week post‐injury. At 8 week post‐transplantation, the viability of FSC was examined by quantifying GFP‐positive area in spinal cord sections. The histological results demonstrated that GFP‐positive area was ~70 % of contralateral (i.e., uninjured side) spinal cord tissue. Immunofluorescence staining revealed that neural cell markers [e.g., neuronal nuclei (NeuN) for neuron; glial fibrillary acidic protein (GFAP) for astrocyte; ionized calcium‐binding adapter molecule 1 (Iba1) for microglia; receptor interacting protein (RIP) for oligodendrocyte] were detected in GFP‐positive tissue. In addition, there are some serotonin and choline acetyltransferase positive cells in the graft region. These results demonstrated that transplants of FSC can survive at least for 8 week post‐transplantation and differentiate into different neural cells, suggesting FSC transplants may have the potential to repair the injured spinal cord.

Support or Funding Information

National Health Research Institutes (NHRI‐EX104‐10223NC); Ministry of Science and Technology (MOST 100‐2320‐B‐110‐004‐MY3)
Time Course of Brainstem Glial Activation Following Exposure to Chronic Sustained Hypoxia
Authors: Arbogast Tara Elizabeth , Stokes Jennifer Ann , Powell Frank L
Published: November 2023

Neuron‐glia communication in the central nervous system (CNS) is proving to be an important component of neuronal signaling and recently we showed that glial activation in the brainstem plays a role in neural plasticity that increases ventilation following chronic sustained hypoxia (CSH) in rats (Stokes JA et al., 2015). In this study we measured the time course of activation of microglia and astrocytes following different lengths of exposure to CSH (10% O2). Rats were exposed to CSH followed by immediate tissue perfusion and brainstem collection at the following time points: 15‐, 30‐ and 60‐minutes, 4‐, 12‐ and 24‐hours, 2‐, 4‐ and 7‐days. We measured activation of glial cells using immunohistochemistry, focusing on respiratory control centers: the nucleus tractus solitarius (NTS) and the retrotrapezoidal nucleus (RTN). Initial results show that microglia (Iba1‐positive cells) display an active morphology at 60 minutes, but are less active in appearance at 24 hours and return to the resting state (as determined by morphology) at 7 days. In contrast, astrocytes progressively increased in GFAP expression over the same time points of 1 hour, 24 hours, and 7 days. The results show that there is an order to glial activation, which we previously showed was necessary for ventilatory acclimatization to hypoxia: microglia are activated first, followed by astrocytes during CSH exposure.

Support or Funding Information

NIH RO1 HL‐081823
Intranasal Neuropeptide Y to Prevent Development of Traumatic Stress Elicited Impairments in Rodent PTSD Model
Authors: Sabban Esther , Serova Lidia , Hansson Evelyn
Published: November 2023

Traumatic stress is a major contributor to the development of PTSD, as well as co‐morbid depression and substance abuse. Treatment of PTSD is extremely challenging and there are few effective options. The NPYergic system is associated with resilience or improved recovery from harmful effects of traumatic stress. Using the single prolonged stress (SPS) model of PTSD, a single infusion of 150 μg NPY immediately after the stressors (SPS/NPY), prevented or greatly reduced development of many of the behavioral, neuroendocrine and molecular impairments (Serova et al, 2013, Neuroscience, 236:298–312; Laukova et al., 2014, Endocrinolgy 155: 3920–33; Sabban et al, J. Neurochem, in press). A week or more after exposure to SPS stressors animals given vehicle (SPS/V) had elevated anxiety, depressive‐like behavior and hyperarousal, especially to high decibels, while the NPY treated rats were similar to unstressed controls. Intranasal NPY also prevented changes in hypothalamus, hippocampus and locus coeruleus. However, all the stressed animals (SPS/V and SPS/NPY) had reduced body weight. Therefor we examined feeding behavior and gene expression in arcuate nucleus, which plays an important role in regulation of food intake and energy homeostasis. With unrestricted access to food, SPS treated animals (SPS/V and SPS/NPY) had reduced food intake in the active (dark) phase as much as two days after SPS stressors. SPS led to reduced mRNA levels of NPY, tyrosine hydroxylase and elevated AGRP mRNA in the arcuate nucleus of SPS/V animals a week after SPS stressors, at time of the behavioral impairments. However these changes in gene expression in the arcuate were not observed in NPY treated animals, which had levels similar to controls. These findings further support likely benefits of early pharmacological intervention with intranasal NPY following exposure to traumatic stress.

Support or Funding Information

US army grant DM102281
Sex differences in alcohol‐induced HPA activation following systemic vs icv administration in rats: Neuronal activation studies
Authors: Davis Seth , Wakley Alexa A. , Yap Parry , Pham Charleen , Kiester Christopher , Selvage Dan John
Published: November 2023

Understanding how alcohol differentially affects the hypothalamic‐pituitary‐adrenal (HPA) axis in males vs. females is important for the development of sex‐specific pharmacological treatments for alcohol abuse. Using intracerebroventricular (icv) administration, our lab previously reported that alcohol activated the hypothalamic‐pituitary‐adrenal (HPA) axis of rats in a sex‐ and estrous cycle‐ dependent manner. This effect was greatest in females in stages of the estrous cycle when the effects of estradiol (E2) are high (proestrus and estrus), as these animals showed greater levels of HPA‐ linked hormonal and neuronal activation by alcohol compared to males and to females in stages of the cycle when E2 levels are low (diestrus I and II). For the current study, we used an intraperitoneal (i.p.) alcohol injection to determine if systemic alcohol activates neuronal HPA activity in a similar manner as centrally delivered alcohol, or whether the many non‐CNS specific effects of the drug in the periphery affect its ability to cause sexually dimorphic activation of the HPA axis. Relative neuronal stimulation levels were determined using single‐ and dual‐ labeling immunofluouresence (IF) staining of the transcription factor and marker of neuronal activity c‐fos (Fos) in the medial parvocellular and magnocellular areas of the paraventricular nucleus of the hypothalamus (PVN), which is known to regulate HPA function. As with icv administration, systemic alcohol induced Fos expression in the medial parvocellular PVN, where cell bodies for corticotropin releasing factor (CRF), the main driver of HPA activation reside. Significant Fos expression was also stimulated in the magnocellular PVN, where cell bodies for arginine vasopressin (AVP), which contributes to HPA activation by CRF, are located. Unlike our results using icv administration, females receiving systemic alcohol exhibited less alcohol‐ induced medial parvocellular PVN Fos than males, with this difference reaching significance in diestrous females. Alcohol also induced less AVP‐ associated magnocellular PVN Fos in females than males following systemic alcohol injection, again with the greatest difference being between males and diestrous females. These results indicate that non‐ CNS specific effects of alcohol in the periphery contribute to HPA responsiveness to the drug in a sexually dimorphic manner, with the male HPA axis exhibiting a significantly greater reactivity to systemic injection of the drug than diestrous females.

Support or Funding Information

NIH R01 AA016947‐01A1
Anti‐diabetic effects of class 1 histone deacetylase inhibition in a rodent model of type 2 diabetes mellitus
Authors: Johnson Emily , Marsh Susan
Published: November 2023

Histone deacetylases (HDACs) have diverse roles in non‐cancerous cells, including an integral role in glucose and fatty acid metabolism. In the heart, class 1 HDACs (HDAC1, 2, 3, and 8) regulate cell growth, and class 1‐specific inhibitors prevent cardiomyocyte hypertrophy. In the pancreas, HDAC inhibition protects β‐cells from apoptosis due to inflammatory insults. Because dysregulated cardiac metabolism, cardiac hypertrophy, and β‐cell apoptosis are complications of type 2 diabetes, we investigated the effects of a class 1 HDAC inhibitor on these outcomes. Type 2 diabetic db/db mice and C57BL/6J controls were treated with romidepsin (FK228), a chemotherapeutic class 1 HDAC inhibitor approved for T‐cell lymphoma, at a low dose (0.56 mg/kg twice a week) for eight weeks. Treatment with romidepsin did not affect heart mass in either genotype. However, in db/db mice romidepsin treatment increased body mass and reduced blood glucose to a level not significantly different from controls. The in vivo blood glucose reduction occurred independent of plasma insulin levels, suggesting that romidepsin is not an incretin; therefore, we investigated the role of class 1 HDACs in intracellular insulin signaling. Results showed that loss of HDAC2 by in vitro siRNA knockdown in AC16 human ventricular cardiomyocytes significantly amplified AKT phosphorylation in response to IGF‐1 treatment compared to IGF‐1 treatment alone. Cumulatively these results show that class 1 HDAC inhibition has anti‐diabetic effects in vivo and suggests that these effects are due to potentiation of intracellular insulin signalling.

Support or Funding Information

S.M. is supported by the Washington State University College of Pharmacy. E.J. is supported by the National Science Foundation Graduate Research Fellowship Program.
Expression of Shaker‐Type Voltage‐gated K+ Channels in Human Conduit and Resistance Arteries
Authors: Nishijima Yoshinori , Cao Sheng , Chabowski Dawid , Ge Chang , Gutterman David , Zheng Xiaodong , Zhang David
Published: November 2023

The expression and function of voltage‐gated potassium (KV) channels have been characterized in different vascular beds from a variety of animal species. Our recent studies indicate that 4‐aminopyridine (4‐AP)‐sensitive KV channels (especially shaker‐type KV1 family) mediate vasodilator responses to hydrogen peroxide (H2O2) in human coronary and adipose arterioles; however, the molecular identity of these KV channels remains unclear. The goal of this study was to identify α‐ (pore‐forming) and β‐ (accessory) subunit composition of KV1 channels using molecular, immunological, and patch‐clamp techniques. Human conduit (>500 μm) and resistance (100–200 μm) arteries were freshly isolated from heart and adipose (subcutaneous and visceral) tissues obtained from unused donor hearts or discarded surgical specimens (n=12 and 15 for heart and adipose tissues, respectively). We first examined mRNA transcripts of KV1α and β subunits using RT‐PCR. Of 9 subunits examined in coronary and adipose vascular tissues, four subunits were consistently detected including KVα1.5 and KVβ1.1–1.3. Other KV1 subunits (KVα1.1–1.4 and α1.6) were variably detected in some but not other tissues. As a positive control, the human brain tissue was found to express mRNAs of all the KV1 subunits. Consistent with mRNA expression profile, KVα1.5 and β1.2 proteins were detected in both coronary and adipose vessels using Western blot. These same tissue samples also revealed protein expression of KVα1.3–1.4 and α1.6. Immunofluorescence assay of freshly dissociated vascular cells revealed that KVα1.5 proteins are abundantly expressed in vascular smooth muscle cells (VSMCs) whereas KVα1.4 and α1.6 seem to be mainly localized in endothelial cells (ECs). Finally, whole‐cell K+ currents recorded from coronary and adipose VSMCs were markedly reduced by 4‐AP (5 mM; general KV blocker) and DPO‐1 (1 μM; KV1.5 blocker). In conclusion, the expression of KV1 channels is highly cell‐specific in human coronary and adipose vessels, with predominant localization of KVα1.5 in VSMCs but different KV1 channels (e.g., KVα1.4 and α1.6) in ECs. How these specific KV1 channels mediate vasodilator responses to H2O2 or other vasoactive agents remains to be determined.
Augmented Expression of Piezo1 in the Uterine Vasculature During Pregnancy
Authors: Ko Nga Ling , Heal Maci , John Liam , Villalba Nuria , Henrion Daniel , Mandala Maurizio , Osol George J
Published: November 2023

The maternal uterine circulation undergoes expansive remodeling during gestation to facilitate the many‐fold increase in uteroplacental blood flow required for normal pregnancy outcome. Although we and others have shown that endothelial nitric oxide (NO) is a key mediator of this process, the primary molecular sensor responsible for detecting shear stress and transducing it to eNOS activation has yet to be identified. The recent discovery of Piezo1 ‐ a large, mechanically‐activated cation channel that has been implicated in mechanosensing of shear stress in various cell types, including the endothelium, inspired this study. Notably, transfection of Piezo1 into HEK293 cells, which normally cannot sense shear stress, conferred a shear stress responsiveness evidenced by increased cytosolic calcium and eNOS activation. We hypothesized that Piezo1 may be present in uterine arteries, and that its expression would be augmented during pregnancy and linked to increased eNOS.

Main uterine arteries (MUA) were collected from adult (12–14 week old) late pregnant (LP: gestational day 20, n=4) Sprague‐Dawley rats, and from age‐matched nonpregnant (NP, n=4) controls. Following euthanization, MUAs were dissected free of surrounding connective and adipose tissues, and cut open to remove any blood present in the lumen. Segments of MUA were either fixed and permeabilized for immunohistochemistry (IHC), or homogenized for Western Blotting (WB). Tissues were incubated with rabbit polyclonal Piezo1 antibody (Ab), eNOS Ab, β‐tubulin Ab; goat anti‐rabbit IgG‐HRP Ab (and/or Alexa Fluor® 488 Ab). Immunolabeled vessels were imaged using a Zeiss LSM 510 META confocal microscope @ 100x; for WB, proteins were detected with chemiluminescent substrate and analyzed using ImageJ software.

Results

(1) Piezo1 was detected in the MUA of both NP and LP rats (using either method), and localized to the arterial endothelium (IHC). (2) Both Piezo1 and eNOS expression were augmented in MUAs from LP vs. NP rats. Based on this preliminary information, we suggest that Piezo1 may play a role in transducing shear stress into the activation of eNOS in the uterine circulation during pregnancy, and thereby contributes to the expansive arterial remodeling required to maintain sufficient uteroplacental perfusion. This is the first study to identify this channel in uterine vessels, and to show a gestational effect on its expression. As both shear stress and uterine arterial remodeling are attenuated in preeclampsia (a serious gestational disease that afflicts ten million pregnant women worldwide each year), understanding the underlying mechanosensing/transducing mechanisms may lead to new therapeutic strategies for augmenting uteroplacental blood flow.

Support or Funding Information

NIH R21 HD080156
Endothelial dysfunction and outward remodeling in coronary and mesenteric arteries in response to high fat diet in mice
Authors: Dunn Shannon M. , Hilgers Rob H. P. , Das Kumuda C.
Published: November 2023

It is well established that vascular endothelial dysfunction is an underlying mechanism in the pathophysiology of hypertension, atherosclerosis, diabetes and other cardiovascular diseases (CVD). Additionally, this cardiovascular pathophysiology is accentuated in aged population. We hypothesize that intake of high fat diet would exacerbate age‐related vascular endothelial dysfunction, promoting the onset and propagation of CVD. To test this hypothesis twelve‐week‐old male mice with C57BL6/J background were randomly divided into four groups and fed normal chow (NC) or HFS (42% fat) for a period of 3 or 12 months. We isolated the left coronary artery (LCA) and 2nd‐order mesenteric artery (MA) and mounted them in the wire‐ and pressure myograph. Both young and aged HFS mice had impaired glucose tolerance as well as an increase in cholesterol levels and weight gain compared to both groups of mice on NC. Aged HFS did have a significant increase in body weight (BW) when compared to young HFS. There was no difference in BW between young and aged mice on NC. Endothelium‐dependent ACh‐induced relaxing responses were blunted in MA and LCA from young HFS compared to young NC mice. Strikingly, this endothelial dysfunction was similar compared to aged NC mice. In addition, endothelial dysfunction in LCA and MA was worsened in aged HFS mice. MA from aged HFS mice developed outward hypertrophic remodeling compared to their younger counterparts and aged‐matched NC mice. These findings suggest that high fat diet in aged individuals can accelerate endothelial dysfunction and increase the risk of CVD.

Support or Funding Information

The work presented here is supported by NIH grant R01HL107885 and R01HL107885‐05S1