bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

IntroductionPeripheral 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.MethodsThe 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.ResultsCompared 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).ConclusionOur data suggest that macrophage activation mediates muscle nociceptor afferent dysfunction in chronic PAD.Support or Funding InformationSupported 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 InformationUTA Start‐up funds to R. Matthew BrothersThis 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 InformationSupported by NIH HL119337This 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 InformationThis 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 InformationResearch funded by Berhane Ghebrehiwet through NIH Grant: 1 R56 AI122376‐01A1This 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 InformationFunding source: NIH 1R01HL130318‐01This 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 InformationUniversity of South Dakota, College of Arts and Sciences and CURCS mini‐grantThis 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 InformationThis 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 InformationThis 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.