bluuebunny/crossref_metadata_2025 huggingface dataset:
Intensity of Voluntary Physical Exercise Affects Vesicle Development and Body Composition in an Animal Model of Endometriosis
Authors: Velazquez Johnathan , Cruz Myrella L , Chompre Gladys , Rivera‐Mendez Raquel M , Maldonado Nicmarie , Appleyard Caroline B
Published: June 2021

Endometriosis is a gynecological chronic condition caused by endometrial tissue migration outside of the uterine cavity. Some symptoms associated with this inflammatory disease are chronic pelvic pain, infertility and painful menstrual cycles. Physical activity has been shown to promote a healthy lifestyle with beneficial effects on chronic inflammatory conditions.

Hypothesis

Intensity of voluntary physical exercise on running wheels has an impact on body composition and will reduce vesicle development in an endometriosis animal model.

Methods

Endometriosis (Endo) was induced (day 0) by suturing uterine horn tissue on the intestinal mesentery of female Sprague‐Dawley rats. Our control rats (Sham) received sutures with no implants. Endo exercise rats were exposed to voluntary exercise in running wheels 14 days before surgery until day of sacrifice (day 60). Sham control and another Endo group were not exposed to exercise. Running wheel activity data (speed, distance and intensity) was collected using Scurry Activity System software. Weight change and food consumption were measured throughout the protocol. At sacrifice, vesicles were collected and measured if present. Mesenteric fat, gastrocnemius and soleus muscles were dissected, weighed and collected.

Results

The Endo exercise group had significantly decreased vesicle size (20.25±5.84mm2) compared to the Endo no exercise group (50.27±9.48mm2, p<0.05). A tendency towards smaller vesicles was observed with increased exercise intensity. The Endo exercise group showed a trend towards gaining less weight, while having a significantly higher food consumption after surgery (p<0.001). The Endo no exercise group had significantly higher amounts of mesenteric fat when compared to the Sham control and Endo exercise groups (p<0.05). The muscle/fat ratio was also increased in the Endo exercise group when compared to the Endo no exercise group indicating differences were due to less presence of fat rather than differences in muscle weight following exercise.

Conclusion

Physical exercise ameliorates the development of vesicles and promotes decreased body fat composition in an animal model of endometriosis. The intensity of voluntary exercise appears to contribute towards the degree of impact on this condition. These results reinforce the potential beneficial effects of voluntary physical exercise as part of a daily routine to reduce endometriosis symptoms in patients.

Support or Funding Information

Supported in part by P20GM103475‐16 & R15AT009915

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Physical Activity and Blood Pressure Reactivity in Young Women with a Family History of Hypertension
Authors: Welti Laura M , Matthews Evan L , Greaney Jody L , Wenner Megan M
Published: June 2021

Healthy normotensive young adults with a positive family history of hypertension (+FH) have increased risk of developing hypertension. Our laboratory has recently demonstrated that young normotensive women +FH display exaggerated blood pressure (BP) reactivity to acute laboratory stressors. Regular aerobic physical activity has been shown to attenuate BP reactivity in populations at risk for future hypertension, however it is unknown whether regular physical activity modulates BP reactivity in +FH young women.

Purpose

To test the hypothesis that young women with +FH reporting regular aerobic physical activity would demonstrate blunted BP reactivity compared to sedentary +FH women.

Methods

We retrospectively analyzed beat‐by‐beat mean arterial pressure (MAP; Finometer) in 14 young women with +FH during three sympathoexcitatory maneuvers: two minutes of a cold pressor test (CPT), two minutes of isometric handgrip exercise at 30% of maximal voluntary contraction (HG), and three minutes of post‐exercise ischemia (PEI). Physical activity data were self‐reported on a standard medical history questionnaire. Women who reported at least four days of aerobic physical activity per week (thus exceeding minimum guidelines) were considered regularly active (+PA; n=7), and less than three days per week were inactive (−PA; n=6). Dare are presented as mean ± SD.

Results

Resting MAP (−PA: 75±10 vs. +PA: 83±18 mmHg: P=0.26) and resting heart rate (HR) (−PA: 75±10 vs. +PA: 60±7 bpm: P=0.06) were not different between groups. BP reactivity during the CPT (ΔMAP: −PA 11±3 vs. +PA 13±7 mmHg, P=0.97), HG (ΔMAP: −PA 18±6 vs.+PA 23±12 mmHg, P=0.71), and PEI (ΔMAP: −PA 14±5 vs. +PA 22±10 mmHg, P=0.16) were not different between groups. Additionally, HR responses during the CPT (ΔHR: −PA 6±8 vs.+PA 4±7 bpm, P=0.74), HG (ΔHR: −PA 14±9 vs. +PA 20±11 bpm, P=0.27) and PEI (ΔHR: −PA 8±8 vs. +PA 3±9 bpm, P=0.45) were not different between groups.

Conclusions

These preliminary data suggest that self‐reported regular aerobic physical activity may not modulate BP responses to sympathoexcitatory stimuli in young women with +FH.

Support or Funding Information

Supported by NIH Grant P20 GM 113125, P20 GM 103446, U54 GM 104941, and The University of Delaware Research Foundation

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Kvβ2 deletion results in hindlimb muscle fibre type switching and enhanced endurance capabilities
Authors: Tur Jared , Chapalamadugu Kalyan C , Tipparaju Srinivas M
Published: June 2021

The Kvβ2 subunit, a member of the Kv (voltage‐gated potassium channel) auxiliary subunits is a dynamic protein interacting with many protein. Previous research has highlighted Kvβ2's abundance during myogenesis and its interactions with key contractility proteins including calmodulin and myosin filaments. Recently we demonstrated that Kvβ2 knockout (KO) mice have a significant increase (+100%) in type I muscle fiber (MHCI) expression within the Soleus muscle compared with wild‐type control mice. Similarly, a significant increase (+47%) in MHCI expression within the Gastrocnemius muscle was also observed within KO mice compared with wildtype. Based upon the deletion of Kvβ2 resulting in altered myofibre distribution towards a slower phenotype, we hypothesize that Kvβ2 KO mice have greater endurance capabilities via a greater presence of oxidative muscle fibers. Indeed, preliminary data utilizing 12–20 week old Kvβ2 KO male mice showed significantly (p<0.01) increased average time in the inverted hang test (534±52s vs. 159±44s) compared with control wildtype. Additional endurance testing utilizing the rotarod demonstrated Kvβ2 KO mice again performed for longer at a given rpm when compared with control mice. While endurance based activities were significantly increased in Kvβ2 KO mice little change was noted in activities which are predominantly fast‐twitch reliant. Grip strength analysis measuring overall force generated demonstrated no significant difference between Kvβ2 KO and control (111±2gF vs. 118±5gF) mice. Overall, this is the first report identifying that genetic deletion of Kvβ2 leads to an increased endurance capacity resulting from a substantial increase in type I muscle fiber expression in hindlimb muscles.

Support or Funding Information

This Research work was funded by National Institutes of Health (NIH) Grant R01‐HL‐102171 (S. M. Tipparaju).

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Hemodynamic Response to Activation of the Exercise Pressor Reflex during Dynamic Plantar Flexion in Peripheral Arterial Disease Patients
Authors: Kim Danielle Jin‐Kwang , Kuroki Marcos , Cui Jian , Pai Samuel , Blaha Cheryl , Luck J. Carter , Gao Zhaohui , Miller Amanda J. , Sinoway Lawrence
Published: June 2021

Patients with peripheral arterial disease (PAD) have an accentuated exercise pressor reflex (EPR). The underlying hemodynamic changes responsible for the exaggerated EPR, and the effect of this on blood flow to the exercising limb is unclear. We tested the hypothesis that the exaggerated EPR in PAD is mediated by an increase in total peripheral resistance (TPR), which augments redistribution of blood flow to the ischemic exercising muscle.

METHODS

Eleven PAD patients and 11 age, and sex‐matched subjects without PAD (control) performed dynamic plantar flexion (PF) using their symptomatic leg at progressive workloads of 2 to 12 kg (increased by 1 kg/min until the onset of fatigue). We measured heart rate (HR), beat‐by‐beat blood pressure (BP), femoral blood flow velocity (FBV), and near‐infrared spectroscopy derived tissue oxygen saturation (SmO2) continuously during the exercise. Femoral blood flow (FBF) was calculated from FBV and baseline femoral artery diameter. Stroke volume (SV), cardiac output (CO), and TPR were derived from the BP tracings.

RESULTS

Mean arterial blood pressure (MAP) was significantly augmented in PAD compared to controls during PF (P < 0.001). This was accompanied by an equal rise in CO in the two groups. Of note, TPR decreased in controls, whereas it increased in PAD. The increase in femoral blood flow velocity was greater during exercise in PAD as compared to controls (P = 0.0021), however, the increased FBF in the two groups was the same. Despite the fact the flow was not different between PAD and control group, SmO2 of the exercising limb remained significantly lower in PAD compared to control (P < 0.001).

CONCLUSION

We conclude that the exaggerated pressor response in PAD is mediated by an abnormal response in TPR, which augments redistribution of blood flow to the exercising muscle, leading to an equal rise in FBF compared to controls. However, this increase in FBF is not sufficient to normalize the SmO2 response during exercise in patients with PAD.

Support or Funding Information

Supported by National Institutes of Health Grants P01 HL134609 (Sinoway) and UL1 TR002014 (Sinoway).

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Muscle Sensory Dysfunction in a Rat Model of Peripheral Arterial Disease: the Role of Macrophage Activation in Chronic Limb Pain
Authors: Qin Lu , Li Ting , Zucker Irving H. , Hong Juan , Lisco Steven J. , Wang Han‐Jun
Published: June 2021

Introduction

Peripheral arterial disease (PAD) is associated with muscle sensory dysfunction. Here, we provide novel evidence demonstrating that macrophage activation in peripheral dorsal root ganglia (DRG) plays a critical role in this process. We hypothesized that inhibition of macrophage activation prevents the reduction in pain threshold in PAD rats.

Methods

The PAD model was developed by unilateral chronic femoral artery occlusion. We examined time‐dependent macrophage activation associated with altered nociceptive protein expression such as transient receptor potential vanilloid 1 (TRPV1) receptor, purinergic 2X3 receptor (P2X3) and vesicular glutamate transporter 1 (vGlut1) in the ipsilateral L4/L5 DRGs of PAD rats. We co‐cultured Lipopolysaccharide (LPS)‐pretreated macrophage (activated macrophages) with 50B11 DRG neurons. The manual monofilament von Frey test was used to evaluate the mechanical pain threshold. To prevent macrophage activation, minocycline was applied to animals 2 days prior to the surgery and lasted for 6 weeks.

Results

Compared to sham rats, the number of Iba‐1‐positive (a macrophage / microglia marker) cells in L4/L5 DRGs of PAD rats was significantly increased at 3 days and lasted at least 2 months post PAD. TRPV1 and P2X3 receptors were initially elevated in the acute PAD phase but significantly decreased in the chronic PAD phase, suggesting a dynamic change of these receptors in PAD. Interestingly, vGlut1 expression was changed in the opposite direction compared to TRPV1 and P2X3 receptors at each stage of PAD. In vitro, 72‐hour co‐culture of LPS‐pretreated macrophages with 50B11 DRG neurons significantly downregulated TRPV1 and P2X3 and increased vGlut1 protein expression in DRG neurons. Compared with baseline, the mechanical pain threshold to the von Frey test was significantly lower at 3 days post PAD and lasted for 6 weeks. Pretreatment with minocycline prevented the decreased mechanical pain threshold in the chronic stage of PAD (e.g., 5 weeks post PAD, PAD + minocycline vs. PAD, 6.62±1.50 vs. 2.26±0.43 g, P<0.05; 6 weeks post PAD, 6.55±1.43 vs. 2.53±0.37 g, P<0.05) but not in the acute stage (e.g., 3 days post PAD, PAD + minocycline vs. PAD, 3.88 ± 0.61 vs. 2.17±0.57 g, P>0.05).

Conclusion

Our data suggest that macrophage activation mediates muscle nociceptor afferent dysfunction in chronic PAD.

Support or Funding Information

Supported in part by grants from the National Heart, Lung, and Blood Institute (1R01HL121012‐01 and R01 HL116608‐01)

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Attenuated Mental Stress‐Induced Brachial Artery Hyperemia in Women Relative to Men
Authors: Olvera Guillermo , Akins John D. , Richey Rauchelle E. , Campbell Jeremiah C. , Martin Zachary T. , Chan Esther Y. , Ogundipe Ayomide O. , Brothers R. Matthew
Published: June 2021

While the contributing factors resulting in hypertension and cardiovascular disease (CVD) are multifactorial, vascular dysfunction and exposure to chronic stress are key contributors. In this regard, previous research has indicated that men and women exhibit differential responses to stress. Acute mental stress (MS) elicits increases in peripheral blood flow that are predominately mediated by the actions of nitric oxide (NO) and thus is a technique that can be utilized to assess vascular function. Previous research has focused on sex differences in the response to MS in a variety of physiological variables; however, the impact of sex on the peripheral blood flow response to MS is less clear. Accordingly, the purpose of this study was to investigate the brachial BF hyperemic response during acute MS between men and women. We hypothesized that the hyperemic response to MS would be similar between the groups. Nine women (studied between days 2–7 of the follicular phase of the menstrual cycle) and seventeen men participated in this study. All measurements were obtained in the supine position following a 15 min baseline period. After the baseline period, the left arm was instrumented for continuous assessment of brachial artery diameter and blood velocity, which were used for subsequent calculation of brachial BF. Continuous arterial blood pressure was obtained on the contralateral arm for calculation of forearm vascular conductance (FVC; Flow/MAP). Brachial BF and FVC were continuously calculated during 2 min of baseline and 3 min of MS induced by asking subjects to subtract 7 continuously from a 3‐digit number while attempting to report answers at a pace set by a 60 bpm metronome. Compared to men, women had a reduced baseline blood flow (men: 84.39 ± 49.39 mL/min, women: 36.79 ± 15.41 mL/min; p = 0.01). In response to mental stress, women also had attenuated responses in the following variables: peak BF achieved during MS (men: 244.94 ± 119.06, women: 141.75 ± 86.98 ml/min; p = 0.03), total BF throughout the duration of MS (men: 408.91 ± 131.10, women: 196.84 ± 86.72 ml/min; p < 0.01) and peak FVC achieved during MS (men: 2.86 ± 1.24, women: 1.13 ± 0.63 mL/min/mmHg; p < 0.01). In conclusion, contrary to our hypothesis, these preliminary findings indicate that women had a reduced hyperemic response in the brachial artery during MS relative to men. Further research is warranted to assess mechanisms of these differential responses between sexes.

Support or Funding Information

UTA Start‐up funds to R. Matthew Brothers

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Mechanisms of Rapid Local Vasodilation During a Mild‐to‐Moderate Exercise Intensity Transition in Humans: Role for K‐IR Channel Activation
Authors: Ketelhut Nathaniel B , Terwoord Janée D , Hearon Christopher M. , Richards Jennifer C , Luckasen Gary J , Dinenno Frank A
Published: June 2021

Potassium (K+) released from skeletal muscle fibers is uniquely situated to initiate rapid vasodilation in parallel with the degree of muscle fiber recruitment, and we have previously demonstrated that activation of inwardly‐rectifying potassium channels (KIR) contributes to the onset of vasodilation and the steady‐state hyperemic response to exercise in humans. Here, we tested the hypothesis that activation of KIR channels underlies the local vasodilation that accompanies a transition from mild‐to‐moderate exercise in humans. We measured forearm blood flow (FBF; Doppler ultrasound) and calculated vascular conductance (FVC; FBF/mean arterial pressure) in 8 young adults (4 male, 4 female) during rhythmic handgrip exercise under control conditions and during local, intra‐arterial infusion of barium chloride (BaCl2) to inhibit KIR− channels. Participants used a handgrip pulley system to perform dynamic forearm contractions (1 sec contraction, 2 sec relaxation) at a mild workload (10% of maximal voluntary contraction; MVC) for 5 min. When the blood flow response to exercise reached steady‐state, there was a step increase to a moderate workload (20% MVC) for 30 sec followed by a return to the 10% MVC workload. Exercise transitions were performed in triplicate (separated by >3 min of mild exercise) and averaged for each subject to determine the hemodynamic response. For each 3 sec duty cycle, FBF and FVC were assessed during cardiac cycles that occurred during relaxation; cardiac cycles that occurred during contractions were excluded to avoid mechanical impedance of blood flow. As expected, KIR inhibition reduced steady‐state FVC during mild exercise by ~ 20% (154 ± 22 vs. 123 ± 17 ml·min−1·100 mmHg−1, P < 0.05). BaCl2 reduced the change in FVC upon transition to a moderate workload by 56 ± 7% (area under the curve; AUC: 60 ± 10 vs. 25 ± 5, P < 0.05), and this reduction was sustained through 5 contraction cycles following the return to mild exercise (15 sec AUC: −31 ± 9 vs. −13 ± 9, P < 0.05). These findings demonstrate a key role for KIR channels in the rapid vasodilation that occurs upon transition to a higher exercise intensity and highlight the link between muscle fiber recruitment and activation of KIR channels.

Support or Funding Information

Supported by NIH HL119337

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Effect of short‐term oral administration of acephate on immune function in mice
Authors: Chen Yuan‐Ru , Chiu Fang‐Yen , Wu Hsin‐En , Lai Yi‐Xin , Li Chia‐Yang
Published: June 2021

Acephate (O,S‐dimethyl acetyl phosphoramidothioic acid), an organophosphate (OP) foliar pesticide, is widely utilized for agriculture and domestic purposes due to its efficiently of insecticide property. The toxicity of acephate is attributed to its bioactivation to methamidophos and inhibits the action of acetylcholinesterase. Previous study has been reported that short‐term oral administration of acephate decreases the number of leukocytes and lymphocytes and reduces serum total proteins and globulins in mice. However, the effect of acephate in regulating immune response has not been well examined. The aim of this study is to investigate whether short‐term oral administration of acephate on immune function in mice. Eight weeks old male C57BL/6 mice were daily oral administration of water or acephate (1/40th of apparent LD50 −8.78 mg/kg or 1/20th of apparent LD50 −17.55 mg/kg) for 28 days. At day 28, a low dose of LPS (1 mg/ml) was intraperitoneally injected into the mice for 6 hr to mimic bacterial infection. The body weight was weighted weekly. The uptake activity of fluorescent conjugated Escherichia coli by leukocytes was analyzed by flow cytometry. Complete Blood Count (CBC), C‐Reactive Protein (CRP), blood urea nitrogen (BUN), creatinine, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) were examined. In addition, the lung, liver and kidney samples were collected and examined by histopathology. This study provides new insight into the toxicity of acephate on immune function.

Support or Funding Information

This study was supported by the Ministry of Science and Technology, Taiwan, R.O.C. (Grant No. MOST 107‐2320‐B‐037‐019).

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Angioedema and Shear Stress Modulate Endothelial Permeability Through gC1qR
Authors: Fandaros Marina , Ong Chloe Leigh , Rubenstein David A , Joseph Kusumam , Kaplan Allen P , Yin Wei , Ghebrehiwet Berhane
Published: June 2021

Angioedema is characterized by swelling in the dermis, oropharyngolaryngeal tissue and/or gastrointestinal wall. In angioedema (AE), vascular wall permeability increases, which is largely due to the overproduction of bradykinin, an inflammatory mediator and vasodilator. The receptor for C1q, gC1qR, has also been identified to play important roles in many physiological/pathological responses. High molecular weight kininogen (HK) can bind to gC1qR on the surface of vascular wall endothelial cells, resulting in the assembly and activation of the kinin/kallikrein system, culminating in bradykinin production. Endothelial cells are sensitive to blood flow‐induced shear stress. It has been established that low shear stress can lead to endothelial cell inflammation and gC1qR upregulation. The goals of the present study are: 1) to investigate how bradykinin and angioedema patients' plasma impair vascular endothelial cell permeability under various shear stress conditions (physiological and pathological); and 2) to determine if a monoclonal antibody (mAb) 74.5.2 known to block the gC1qR/HK interaction can also effectively block this response. To this end, human umbilical vein endothelial cells (HUVECs) were grown to confluence in polycarbonate transwell plates and exposed to 30 minutes of shear stress (1, 5 and 10 dynes/cm2) in the presence or absence of bradykinin or angioedema patients' plasma. FITC‐conjugated bovine serum albumin (BSA) was added to the upper chamber of the transwells before shearing. Endothelial cell permeability was measured by the amount of FITC‐BSA leaked to the bottom chamber of the transwell at the end of the experiment. Cell surface gC1qR expression was measured using a solid‐phase ELISA. Endothelial cell morphology following treatment (shear stress, bradykinin and AE plasma) was quantified using immunofluorescence microscopy. To confirm that mAb 74.5.2 can effectively block HK binding to gC1qR, purified gC1qR was coated on a 96‐well microtiter plate. After incubation with 74.5.2, HK binding was measured using ELISA. The results demonstrated that both bradykinin and AE plasma can significantly enhance gC1qR expression and damage endothelial cell integrity (i.e. permeability), especially under low shear stress (1 dynes/cm2). Monoclonal antibody 74.5.2 could significantly inhibit HK binding to immobilized gC1qR (by more than 40%). These results suggest that gC1qR is a major mediator in angioedema, especially under pathological low shear stress. Inhibiting HK binding to gC1qR using 74.5.2 could be an effective therapeutic solution to prevent angioedema.

Support or Funding Information

Research funded by Berhane Ghebrehiwet through NIH Grant: 1 R56 AI122376‐01A1

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Mitochondrial Respiration and H2O2 Emission in Saponin‐permeabilized Murine Diaphragm Fibers: Optimization of Fiber Separation and Comparison to Limb Muscle
Authors: Hahn Dongwoo , Kumar Ravi A , Ryan Terence E , Ferreira Leonardo F
Published: June 2021

Chronic diseases such as cancer, COPD, and heart failure impair diaphragm metabolism and mitochondrial function. Mice are used extensively to replicate disease conditions and offer the advantage of studying genetically modified animals. Mouse diaphragm contains a high abundance of connective tissue, with relatively thin (15–25 μm diameter) and fragile fibers. In preliminary studies, we discovered that standard fiber separation approaches utilized for limb muscles are unsuitable for the diaphragm. Thus, the purpose of this study was to optimize a protocol for diaphragm (Dia) fiber bundle preparation to evaluate the mitochondrial respiration and reactive oxygen species emission. We used the red gastrocnemius (Gast) muscle as a ‘standard’ for comparison.

Michaelis‐Menten kinetics of ADP‐stimulated O2 consumption with complex I substrates (JO2 in pmol/s/mg wet weight) showed 3‐fold higher Vmax in Dia than Gast (Gast 69 ± 18, Dia 211 ± 20; p < 0.05, n = 9 mice), whereas Km was not significantly different. Maximal JO2 in Dia was 3‐fold higher with complex I + II substrates (Gast 148 ± 25, Dia 387 ± 45; p < 0.05), and 2‐fold higher with palmitoyl‐CoA + carnitine (Gast 7 ± 0, Dia 15 ± 2, p < 0.05) compared to Gast. Baseline JH2O2 (pmol/min/mg wet weight) was higher in Dia (Gast 0.8 ± 0.2, Dia 1.7 ± 0.3; p < 0.05), but succinate‐induced JH2O2 was not different between muscles. Citrate synthase activity was 3‐fold higher in Dia (μmol/min/mg protein: Gast 43 ± 3, Dia 118 ± 4; p < 0.05). The protein abundance of electron transport chain complexes I‐V were 2–4 fold higher in the Dia than Gast (p < 0.05). When we normalized maximal JO2 by citrate synthase activity, there were no differences between Dia and Gast for complex I and complex I + II substrates. JH2O2 normalized to citrate synthase activity was higher for Gast at baseline (pmol/min/mg wet weight/U CS: Gast 2.1 ± 0.3, Dia 0.3 ± 0.1; p < 0.05), but there was no difference in succinate‐induced JH2O2 normalized to citrate synthase activity.

The values for maximal diaphragm mitochondria JO2 in our study are 2–3 fold higher than reported in the literature using the standard ‘limb muscle’ approach for the diaphragm fiber preparation. The similar maximal JO2 normalized to citrate synthase activity between diaphragm and red gastrocnemius muscles suggest that our new approach is valid for the assessment of intact diaphragm mitochondrial function in permeabilized fiber bundles.

Support or Funding Information

Funding source: NIH 1R01HL130318‐01

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Transcriptome Gene Expression and It's Relation to Muscle Performance in Anolis Lizards
Authors: Smith Luke Brendan , Anderson Christopher , Roberts Thomas , Zeng Erliang , Liebl Andrea
Published: June 2021

Animal muscles are exceptionally diverse in structure and function as they meet a variety of demands for an individual to survive. Whole organisms must adapt to their environments. However, specific muscles vary to best suit each muscle's role in promoting organism survival; differences in gene expression among muscles likely accounts for this variation. Anolis lizards, a species that has undergone adaptive radiation, live in a wide range of habitats and ecotypes to which each species has had to evolve appropriately to survive. Unsurprisingly, the muscle performance of these lizards (e.g., twitch time and peak contractile velocity) varies among muscle types. Specifically, the performance of jaw and leg muscles, strongly selected for because of their importance for survival (e.g., to escape predation and to bite prey), differ between the muscles both across and within individuals. Here, we use RNA‐seq to measure the underlying molecular mechanisms generating these differences. Using gene networks, we are able to differentiate the two types of muscles. The observed discrepancy in gene expression are expected to explain the divergence in performance we observe between the muscles. Determining the underlying differences in gene expression between muscles and individuals will help explain how performance metrics (e.g., twitch time and peak contractile velocity) change over time and how the ecology and evolution of an individual influences it.

Support or Funding Information

University of South Dakota, College of Arts and Sciences and CURCS mini‐grant

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Relationship between Morphometric Measurements and Leptin Levels of Horses Vary Among Breeds
Authors: Harms Abigail Rachel , Martinez–Flores Brenda Rachel , Moffatt Cheyenne N , Paquin Zachary W , Guild Ayla , Johnson Kathryn M.S.
Published: June 2021

Obesity in domestic horse populations is becoming more prevalent, manifesting in increased occurrences of metabolic issues. Currently, obesity in horses is determined by subjective visual assessment, which is not reliably standardized. Circulating leptin levels directly correlate with adipose tissue mass; therefore, leptin levels could potentially be used as an objective measure of obesity in horses. To determine the relationship between body mass, as defined by morphometric measurements, and plasma leptin levels, blood was collected via jugular vein from horses (n=35) from four different breeds with known varying risks of obesity and obesity‐related conditions (Saddlebreds, n = 7, draft/draft crosses, n=7, stock horses, n=11, and Welsh ponies, n=10), in southern Wisconsin and northern Illinois every 60 days for one year. Morphometric measurements included neck circumference, height, and girth. These measurements were used to calculate neck circumference to height ratio (NCHR) and girth to height ratio (G:H). For both NCHR and G:H calculations, a greater value indicates increased obesity. Plasma leptin levels (repeated measures MANOVA, F3,29=5.65, p=0.004), NCHR (repeated measures MANOVA, F3,31=26.64, p<0.0001), and G:H (repeated measures MANOVA, F3,31=23.00, p<0.0001) varied significantly among breeds. In addition, the relationship between leptin levels and NCHR (repeated measures MANOVA, F3,29=6.44, p=0.002) and leptin levels and G:H (repeated measures MANOVA, F3,29= 6.55, p=0.002) varied significantly among breeds. Among these results, post hoc analysis revealed Saddlebreds had the highest leptin levels (pairwise contrast, F1,29=10.51, p=0.003), lowest NCHR (pairwise contrast, F1,31=52.87, p<0.0001), and lowest G:H (pairwise contrast, F1,31=60.93, p<0.0001) compared to all other breeds. This suggests Saddlebreds have a different relationship between obesity and leptin levels compared to other breeds. Saddlebreds are known to have various metabolic issues, such as an increased risk of insulin resistance, even when visual inspection and exercise regimen would suggest normal insulin sensitivity. Therefore, unique relationships between leptin levels and obesity in some horse breeds may be associated with varying risks of obesity‐related conditions.

Support or Funding Information

This work was sponsored by the Biomedical Scholars Program at Beloit College.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Adeno Associated Virus Mediated Neural Tracing of TRPV1‐Expressing Airway Afferent Nerves
Authors: Kim Seol‐Hee , Taylor‐Clark Thomas
Published: June 2021

The various sensory nerve subtypes deliver different types of information to brainstem in which the integration of the information takes place to regulate respiratory reflexes. The bronchopulmonary C‐fibers, the main sensory afferent regulating respiratory reflexes, arise from vagal ganglia and those are known to innervate the nucleus of the solitary tract in the medulla. However, the innervation patterns may vary depending on the subsets of vagal afferents. Vagal afferent nerve subtypes express particular ion channels/receptors which are stimulated by various stimuli resulting in different information being conveyed to the brainstem. The variation makes it difficult to understand how distinct peripheral vagal afferent inputs are processed in the central nervous system.

In the current study, we determined the central projections of Transient receptor potential vanilloid 1 (TRPV1)‐expressing vagal sensory afferent innervating the airways using AAV mediated retrograde neural tracing. TRPV1 is expressed on nociceptive afferents involved in defensive/protective reflexes (e.g. cough, apnea). TRPV1‐Cre mice were used, along with a rAAV2 vector with a flex‐tdTomato reporter. In the presence of cre the AAV will be recombined to express tdTomato. Without cre the AAV does not express the reporter. Mice (6 to 8‐week‐old) received intratracheal instillation of AAV virus and housed for three weeks. Vagal ganglia and brainstem were collected and cryosectioned sequentially. Immunohistochemistry was performed and images were taken using Olympus FV1200 confocal microscope.

As a result, we observed tdTomato labeled cells and nerves in vagal ganglia. With immunohistochemistry using anti‐DsRed and anti‐TRPV1 antibodies, we confirmed that the red fluorescent cells and nerves are TRPV1 positive. In medulla, we were able to see tdTomato labeled projections starting from caudal (approximately −780 μm to obex) to rostral (approximately +210 μm to obex) ends of medulla. The tdTomato labeled projections are mainly located in the nucleus of solitary tract (NTS) as well as along the solitary tract. The tdTomato labeled projections were seen mainly in gelatinous NTS and dorsolateral NTS, as well as in area postrema. These data suggest that airway nociceptor central terminals are located within a specific region of the NTS.

Support or Funding Information

This study is funded by National Institutes of Health Common Fund SPARC OT2 (2016–2019): “Functional mapping of peripheral and central circuits for airway protection and breathing”

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Intercalation of swallow and breathing recorded optically in the sagittally‐sectioned rat hindbrain
Authors: Huff Alyssa D , Pitts Teresa , Gourévitch Boris , Mellen Nicholas
Published: June 2021

The ventral respiratory column (VRC) contains heterogeneous neurons that generate and regulate respiration as well as other orofacial behaviors. In neonate SD rat, the VRC extends over 2 mm from the rostral margin of the facial nucleus (VIIn). In addition, networks that modulate breathing on a cycle‐to‐cycle basis are distributed along the dorsomedial margin of brainstem in or near the nucleus tractus solitaries (NTS): these include central networks that intercalate swallow into the respiratory pattern, and the first synapse of lung mechanoreceptors responsible for the Breuer‐Hering (BH) reflex. Both the VRC and NTS are exposed at the surface of the sagittaly‐sectioned rat hindbrain preparation (SSRH), enabling the induction of swallowing, as well as BH via bipolar electrode stimulation. Using previously‐described methods, coupling relations between VRC respiratory neurons before and during induced swallow and BH were obtained via high‐speed optical recordings along the entire VRC. Fluctuations in [Ca2+]I were detected using the medium‐affinity membrane permeant indicator fluo‐8L (KD=1.86 □M, AAT labs). Datasets were aligned using the caudal pole of the VIIn (VIIc) and the minimum of the concavity of the ventral surface at VIIc as rostrocaudal and ventrodorsal landmarks. Importantly this preparation allows for experimental conditions, which can directly test hypothesis related to swallow‐breathing coordination, and identify novel populations of neurons not currently recognized in the swallow central pattern generator.

Support or Funding Information

This work was supported by NIH grants HL 111215, HL 103415 and OT20D001983, the Craig F. Neilson Foundation Pilot Research Grant 546714, Kentucky Spinal Cord and Head Injury Research Trust, and the Commonwealth of Kentucky Challenge for Excellence.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Cluster Analysis of Neuronal Discharge Patterns During Breathing and the Laryngeal Adductor Reflex with Computer Simulations and Dynamic Visualizations
Authors: Morris Kendall F. , Shuman H. Dale , O'Connor Russell , Nuding Sarah C. , Horton Kofi‐Kermit , Alencar Pierina Ashley , Bolser Donald C. , Davenport Paul W. , Gestreau Christian , Pitts Teresa G. , Lindsey Bruce G. , Segers Lauren S.
Published: June 2021

The laryngeal adductor reflex (LAR) is a simple airway protective behavior that closes the vocal folds in response to mechanical or chemical stimulation of sensory afferents in the larynx. Previous work suggested that the intra‐medullary pathway that is responsible for activating laryngeal motoneurons is composed of as little as two synapses. We speculated that the central pathways supporting this behavior are more complex and involve neurons of several different phenotypes. Breathing and non‐breathing modulated neurons (n=632) were recorded with multiple electrode arrays in the ventral respiratory column (ventral respiratory group, pre‐Bötzinger, Bötzinger), pons, raphé, dorsal lateral medulla and spinal cord of decerebrate, paralyzed, vagus‐intact cats (n=13). The LAR was induced by electrical stimulation of the superior laryngeal nerve. We classified brainstem neuron activity phenotypes using a quantitative, reproducible clustering routine during baseline breathing and the LAR. We identified 25 breathing phenotypes that were mapped onto 16 LAR phenotypes. These results were used to produce a simplified model and simulations of the LAR. A 3‐D brainstem atlas displayed neuronal firing rates during periods of baseline breathing and/or the LAR, illuminated in proportion to firing rate. These data support distinct rather than a continuum of phenotypes based on discharge patterns during breathing as well as during the LAR.

Support or Funding Information

Support: OT2OD023854‐01, HL109025, HL131716

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Neuronal Correlates Mediating the Pontine Modulation of the Hering‐Breuer Expiratory Facilitatory (HBEF) Reflex
Authors: Zuperku Edward J , Stucke Astrid G. , Tomlinson Jack , Krolikowski John G. , Hopp Francis A. , Stuth Eckehard A.
Published: June 2021

The gain of the HBEF is controlled by neurons in the medial parabrachial (PB) region (1). However, the mechanism is unknown. Responses of E decrementing (Edec) neurons to inputs from slowly adapting pulmonary stretch receptors (PSRs) suggest that they may mediate the HBEF reflex (2). This study analyzed the responses of E‐neurons in the pre‐Bötzinger/Bötzinger (preBC/BC) region to inputs from both the PSRs and PB neurons in a decerebrate vagotomized dog model. Neurons were recorded with a 16‐electrode probe. Weak electrical stimulation (~100 μA & 100 μs duration) of the central end of a desheathed cervical vagus nerve was used to activate PSR afferents and a concentric bipolar microelectrode was used to activate the PB region neurons. Post‐stimulus time histograms triggered by stimulus sync pulses (10 Hz for 10 min) were used to detect the presence of synaptic inputs to E‐neurons by either or both of these inputs. Cycle‐triggered histograms triggered from the phrenic neurogram (PNG) were used to analyze induced‐changes in average discharge (Fn) patterns. The data from this study and a previous study (2) show that the decrementing rate of ~all Edec neurons decreases and the discharge duration increases with the PSR‐induced increases in expiratory duration (TE). About 60% (11/18) of the Edec neurons received an inhibitory input from the PB region (3). CTHs show that concurrent PB and PSR stimulation depress the PSR‐mediated increase in TE and depress Edec discharge patterns (e.g., see figure). This finding suggests that gain modulation of the HBEF reflex by the PB region may be mediated by inhibitory inputs to Edec neurons in the preBC/BC region.

Support or Funding Information

Supported by VA grant 2 I01BX000721‐08 (Zuperku) & R01GM112960‐01A1 (Stucke)

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Endogenous mechanism of right ventricular repair in pulmonary hypertension
Authors: Shults Nataliia , Rybka Vladyslava , Suzuki Yuichiro J.
Published: June 2021

Introduction

Right‐sided heart failure is the major cause of death among patients with pulmonary hypertension (PH) as well as children who suffer from various forms of congenital heart disease. Thus, agents that repair the damaged right ventricle (RV) have therapeutic potential to treat right‐sided heart failure. The biology of RV, however, is not well understood. The present study describes an endogenous mechanism for RV repair that was discovered in an experimental animal model of PH.

Methods & Results

The treatment of Sprague‐Dawley (SD) rats with the injection of SU5416 (VEGF inhibitor) and 3 weeks of chronic hypoxia, followed by the maintenance in normoxia, resulted in progressive PH and RV remodeling. At 17 weeks after the initiation of the treatment, RV cardiomyocytes were damaged and the fibrotic region was found to be 12% of the total RV. However, at 35 weeks, RV fibrosis was significantly reduced and new cardiomyocytes were regenerated, despite RV pressure remained elevated. Before the RV repair occurs, α‐smooth muscle actin (αSMA) was found to be expressed in myofibroblasts. In addition, we noted the expression of αSMA in some of RV cardiomyocytes. Normal terminally differentiated cardiomyocytes do not express αSMA, but induced cardiomyocytes (iCMs) derived from induced pluripotent stem cells (iPSCs) do. Thus, we hypothesized that the damaged RV is repaired by activating the cellular reprogramming process that converts resident cardiac fibroblasts into iCMs perhaps through an iPSC‐like mechanism. This hypothesis was substantiated by our observations that Sox2, stem cell‐specific transcription factor, was also expressed in RV cardiomyocytes being repaired. Further, transmission electron microscopy observations revealed that extracellular matrix contains fibroblast‐line cells with myofilaments, which are organized into myofibrils and formed into the sarcomere‐like structure similar to iCMs.

Conclusions

The RV damage promoted by PAH can be repaired through a naturally occurring process that may involve cardiomyocyte regeneration through cell reprogramming. Understanding such an endogenous repair mechanism should contribute to the development of therapeutic strategies to treat right‐sided heart failure.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
H2S Contributes to Carotid Body Response to Hypoxia but Not Anoxia
Authors: Peng Ying‐Jie , Makarenko Vladislav , Nanduri Jayasri , Chupikova Irina , Girdina Anna , Zhang Xiuli , Kumar Ganesh , Fox Aaron , Prabhakar Nanduri R
Published: June 2021

We previously reported that cystathionine‐γ‐lyase (CSE)‐derived H2S mediates carotid body (CB) response to hypoxia (Hx) (Peng et al., PNAS, 2010). A recent study showed that CB Type I cell responses to anoxia (Ax) were unaffected by CSE inhibitors (Kim et al. Respir Physiology, 2015). We re‐examined the role of CSE‐derived H2S in CB sensory and Type I cell responses to Hx and Ax in adult Sprague‐Dawley rats, wild‐type and CSE knockout (KO) mice. Hx (pO2=37± 3mmHg) produced robust sensory excitation, and increased H2S levels in the CB; whereas Ax (pO2 =5±4 mmHg) produced only a weak sensory excitation and had no effect on H2S levels. Ax evoked a robust [Ca2+]i response of Type I cells as compared to hypoxia. CSE inhibitor DL‐propargylglycine (DL‐PAG, 50μM) inhibited Hx but not Ax‐evoked sensory and Type I responses. Higher concentration (300μM) of DL‐PAG alone, or in combination with aminooxyacetic acid (300μM), non‐selectively blocked [Ca2+]i responses of Type I cells to Ax and decreased cell viability. CB sensory excitation and [Ca2+]i elevation in Type I cells were unaffected in CSE null mice as compared to wild‐type (Wt) mice. Breathing stimulation by Hx was absent in CSE KO mice, whereas depressed breathing by Ax was unaffected. These observations suggest that CSE‐derived H2S contributes to carotid body response to “physiologically” relevant hypoxia but not to anoxia.

Support or Funding Information

Supported by National Institutes of Health grants P01‐HL‐90554

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Hippocampal neural stem cells undergo fate switch following intermittent hypoxia
Authors: Khuu Maggie A. , Nallamothu Thara , Garcia Alfredo J.
Published: June 2021

Adult neurogenesis is a phenomenon widely recognized as a process supporting neurophysiology of the hippocampus. We recently reported that 30 days of intermittent hypoxia (IH), a principal consequence for sleep apnea, stimulates the expansion of hippocampal neural stem cells (NSCs), yet suppresses the generation of adult‐born neurons. This study investigates how IH impacts NSCs by using a shorter duration of IH. We hypothesize that 10 days of IH (IH10) redirects the course of development of NSCs. We examined how NSCs in the neurogenic niche of the dentate gyrus are affected by IH10. Immunohistochemical analysis revealed that the number of NSCs (Sox2+ cells) was not increased following IH10, yet appears to increase in quiescent NSCs (i.e., Sox2+ cells that co‐express the astrocytic marker, S100b, and do not develop into adult‐born neurons). Fewer NSCs were observed transitioning into intermediate neuronal progenitors (INPs, SOX2+/TBR2+ cells) and a reduction in the total number of INPs (TBR2+ cells) was also noted. These experiments suggest that the impact of IH on cells involved with adult neurogenesis is cell‐type specific. Our findings provide further support that untreated sleep apnea may impact the fate of pluripotent cellular constituents in the central nervous system.

Support or Funding Information

This work was supported by NIH R01 NS10742101 (AJG)

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.