bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sinoaortic denervation reduces the complexity of heart rate variability in mice
Authors: Silva Luiz Eduardo , Rodrigues Fernanda , Oliveira Mauro , Salgado Helio , Fazan Rubens 
Published: June 2021

Heart rate variability (HRV) is recognized as a phenomenon highly complex, presenting nonlinear dynamics with fractal correlations and multiscale properties. Several cardiovascular and systemic diseases are related to loss of complexity in HRV, which has been recognized as an independent risk factor for life‐threatening cardiovascular outcomes. Considering that most cardiovascular diseases are accompanied by autonomic imbalance and baroreflex dysfunction, we hypothesise that the baroreflex may play an important role in the genesis of HRV complexity. Mice were submitted to sinoaortic denervation (SAD) and received catheters into femoral artery and jugular vein 5 days prior to the experiment. Baseline arterial pressure (AP) was recorded and pulse interval (PI) time series were generated from the intervals between consecutive diastolic pressures. The complexity of the HRV was determined using detrended fluctuation analysis (DFA) and multiscale entropy (MSE). DFA α1 scaling exponent (a short‐term index) was remarkably decreased in the SAD mice (0.79±0.06 vs. 1.13±0.04 for the control mice), whereas SAD slightly increased the α2 scaling exponent (a long‐term index: 1.12±0.03 vs. 1.04±0.02 from control). In SAD mice, total MSE was decreased (13.2±1.3) compared to the control counterparts (18.9±1.4). In conclusion, both fractal and regularity structures of HRV are altered by SAD in mice, affecting short‐ and long‐term mechanisms of complexity, suggesting that the baroreceptors play a important role in the complex structure of HRV.Finacial Support: FAPESP, CAPES, CNPq
Vagal nerve stimulation suppressed the inflammatory response in chronic heart failure before improving hemodynamics
Authors: Nishizaki Akiko , Saku Keita , Ide Tomomi , Kishi Takuya , Sunagawa Kenji 
Published: June 2021

BackgroundAlthough vagal nerve stimulation (VNS) significantly improves chronic heart failure (CHF) independent of heart rate (HR) reduction, the mechanism which benefits CHF remains unknown. It is also well known that VNS exerts the anti‐inflammatory response. In this study we investigated how VNS regulates the inflammatory response of CHF after myocardial infarction (MI) in rats.MethodsIn 8 weeks Sprague‐Dawley rats, we created MI. We implanted a device for VNS and started stimulation from 2 weeks after MI (CHF: n=15, VNS: n=15). We titrated VNS below its bradycardia threshold. To elucidate the pure impact of VNS on inflammatory response, we evaluated invasion of macrophages and inflammatory cytokines in 3 days after VNS. In some rats, we evaluated hemodynamics and infarct size in 4 weeks after VNS.ResultsIn 3 days, VNS did not change LVEF (CHF: 33.4±5.6, VNS: 34.8±6.9%) or LVEDP (CHF: 15.8±7.5, VNS: 12.1±7.2 mmHg). In contrast, VNS significantly reduced the invasion of macrophages in the left ventricle (LV) (CHF: 295.1±142.1, VNS: 110.7±59.6 counts/mm2, p=0.001) and plasma interleukin‐1β(IL‐1β)(CHF: 75.7±27.6, VNS: 32.9±6.8 pg/mL, p=0.0002) as well as that of heart and spleen. In 4 weeks, VNS markedly decreased LVEDP (CHF: 24.2±5.0, VNS: 17.5±7.1 mmHg, p=0.002) and heart weight (CHF: 3.7±0.5, VNS: 3.2±0.5 g/kg, p=0.0005), whereas the infarct size remained unchanged.ConclusionVNS showed the anti‐inflammatory responses 3 days after the beginning of stimulation. The VNS induced anti‐inflammatory response is by far earlier than its impact on hemodynamics and LV systolic function. The VNS induced anti‐inflammatory response may play a major role in preventing cardiac remodeling and improving LV function in the long term.
Sympathetic Tone Differentially Regulates MHC‐II Expression by Macrophages and Enteric Glia in the Gastrointestinal Tract
Authors: Vanderkamp Robert , Chow Aaron , Garver Hannah , Fink Gregory , Gulbransen Brian 
Published: June 2021

The sympathetic nervous system modulates essential gut functions including motility, blood flow, and gut immunity. Yet how sympathetic innervation regulates the function of specific immune cell types in the gut is poorly understood. Norepinephrine regulates expression of major histocompatibility complex (MHC) class II molecules in astrocytes and microglia in the brain. We aimed to test the hypothesis that sympathetic innervation of their counterparts in the gut, enteric glia and macrophages, regulates their antigen‐presenting capacity by modulating MHC‐II expression.We tested our hypothesis by assessing MHC‐II expression by enteric glia or macrophages before and after removal of sympathetic tone by surgery or treatment with 6‐hydroxydopamine. Expression of MHC‐II by enteric glia or macrophages was assessed by dual‐label immunohistochemistry and mean fluorescence compared with Student's t‐test.Sympathectomy increased expression in macrophages by 260% (P<.005). In contrast, sympathectomy had no effect on MHC‐II expression by enteric glia. Elevated MHC‐II expression in macrophages was not due to increased macrophage numbers because macrophage densities were not altered by denervation. Our results suggest that sympathetic tone suppresses expression of MHC‐II in macrophages. Expression of MHC‐II by enteric glia may require other cues.Funded by the Larry D. Fowler Undergraduate Research Stipend
Chronic Salt‐Loading Alters Pre‐Autonomic Neuropeptide Expression in the Paraventricular Nucleus
Authors: Smith Justin , Pati Dipanwita , Hiller Helmut , Wang Lei , Frazier Jason , de Kloet Annette , Krause Eric 
Published: June 2021

A high‐salt diet and disregulated stress‐responsiveness are known risk‐factors for the development of hypertension and heart disease. Corticotrophin‐releasing factor (CRF) initiates the neuroendocrine response to stressful stimuli and is situated in close proximity to osmosensitive arginine‐vasopressin (AVP) and oxytocin producing neurons in the paraventricular nucleus of the hypothalamus (PVN). To investigate the effect salt‐loading has on CRF neurons, we utilized the Cre‐lox system to generate mice that express red fluorescent protein driven by CRF transcription. These CRF‐reporter mice had water replaced with 2% NaCl for 5 days ending in a 30 min restraint challenge. Compared with mice maintained on water, salt‐loaded mice drank up to 150% more fluid and had significantly higher plasma sodium, but food intakes and body weights were similar. In situ hybridization for CRF mRNA resulted in salt‐loaded mice exhibiting a decreased restraint‐induced CRF expression in the PVN specifically in neurosecretory regions, but an increase in pre‐autonomic areas. Analysis of cells labeled with retrograde tract tracer injected into the ventral‐lateral medulla confirmed an increase in the frequency of pre‐autonomic neurons expressing AVP and CRF in the PVN with salt‐loading. Whole‐cell patch clamp recording of CRF positive PVN cells found significantly fewer spontaneous excitatory postsynaptic currents; however, glutamatergic synapses onto these cells were upregulated. Collectively, these results show the plasticity of stress‐responsive neurons which may contribute to the anxiolytic and cardiovascular effects of high‐salt diets.Support: HL‐096830 (EGK), HL116074 (ADK)
Selective inhibition of the adrenergic C1 neurons reduces the hypoxic ventilatory response in unanesthetized rats
Authors: Malheiros‐Lima Milene , Takakura Ana , Moreira Thiago 
Published: June 2021

The catecholaminergic (TH) neurons that reside in the rostral half of the ventrolateral medulla (VLM), also called C1 neurons, regulate blood pressure, the CRF/ACTH/corticosterone cascade and autonomic glucoprivic responses. The stimuli that most commonly activates the C1 neurons (nociception, hypotension, and hypoxia) also increases breathing. Although pharmacological evidence suggests that catecholaminergic neurons regulate breathing, a specific contribution of the C1 neurons to respiratory control has not been demonstrated, particularly in vivo. Here, we evaluate the role of the C1 cells in the control of breathing under hypoxia (8% O2) or hypercapnia (7% CO2) condition in unanesthetized rats. Bilateral injection of the immunotoxin anti‐dopamine β‐hydroxylase‐saporin (anti‐DβH SAP) was done in adult unanesthetized male Wistar rats (270‐300g, N = 4‐7/group). Bilateral injections of anti‐DβH SAP (2.1 ng/100 nl) into VLM destroyed TH neurons. Selective inhibition of the C1 cells with bilateral injection of anti‐DβH‐SAP into the VLM reduced the increase in respiratory frequency (fR) (110 ± 5, vs. saline 136 ± 17 bpm), tidal volume (VT) (2.3 ± 0.2, vs. saline: 2.9 ± 0.3 ml/kg), and minute ventilation (MV) (244 ± 16, vs. saline: 402 ± 90 ml/kg/min) elicited by hypoxia (8% O2). Hypercapnia challenges (7% CO2) caused graded increases in fR, VT, and MV, however, the changes in breathing elicited by hypercapnia was not altered after selective destruction of C1 cells in the VLM. The present study indicates that C1 neurons could be involved in the regulation of breathing and provide evidence that they may contribute to the hypoxic ventilatory response.Financial support: FAPESP, CNPq, CAPES/PROEX.
P2X3 receptor‐mediated chemoreceptor hypersensitivity in young spontaneous hypertensive rats
Authors: Moraes Davi , Machado Benedito , Ford Anthony , Paton Julian 
Published: June 2021

Sympathetic overactivity has been related to the pathogenesis of hypertension. Enhanced peripheral chemoreceptor sensitivity has been suggested as a possible mechanism for sympathetic overactivity. We compared both baseline and chemoreflex evoked carotid sinus nerve (CSN) activity, and the electrophysiological properties of petrosal ganglion cells (PGc) innervating the carotid body in in situ preparations of young spontaneously hypertensive (SH) and Wistar rats. Since ATP plays a major role in chemosensory transduction in the carotid body, we also evaluated the contribution of ATP and P2X receptors in PGc and their involvement in sympathetic overactivity observed in SH rats. SH rats (n=22) presented: increased basal and chemoreflex evoked CSN discharge, and the electrical excitability of PGc was elevated relative to Wistar rats (n=25). A significant increase in the depolarizing effects of ATP and α,β‐methylene ATP in SH (n=18) versus Wistar (n=16) PGc was observed. This was consistent with raised single‐cell mRNA expression of ionotropic P2X3 channels (n=12) in SH rats. Moreover, both the increased baseline and chemoreflex evoked sympathetic nerve response in SH rats (n=12) was markedly reduced after perfusion of the PG with AF‐353, a selective antagonist of P2X3 receptors. Our results suggest that ATP and P2X3 receptors play an important role as a novel mechanism for increased carotid body tone and hyper‐chemosensitivy that contributes to the sympathetic overactivity in SH rats.Support: British Heart Foundation and FAPESP
CB1 receptors into the Prelimbic Cortex modulate food intake in rats.
Authors: Scopinho América , Resstel Leonardo , Corrêa Fernando 
Published: June 2021

The endocannabinoid system is involved in the central regulation of feeding behavior. Systemic administration of exogenous cannabinoids or endocannabinoids stimulates eating, and systemic administration of CB1 antagonist attenuates agonists' stimulatory effects on food intake, suggesting the involvement of these receptors in food intake modulation. Although CB1 receptors are present principally in the central nervous system (CNS), little is known about which areas are involved in this modulation and the role of endocannabinoids system. Therefore, the aim of the present study is to investigate the effects evoked by CB1 receptors antagonist (AM251) microinjected in the prelimbic cortex (PL) on the food intake regulation.CB1 receptor antagonist AM251 (10, 50, 100pmol/100nl) or aCSF‐ artificial cerebrospinal fluid were microinjected into the PL of fed or fasted Wistar rats and 10 min later, the food intake test was performed during one hour for food intake determination.The amount of food ingested by fasted animals was significantly higher than fed animals (F(1, 48) = 482,2; P<0.001). Moreover, significant effects of treatment with doses of AM251 (F(3, 48) = 74,41; P<0.001) and interaction between the two factors F(3, 48) = 78,26; P<0.001) for total food intake (n=6‐8 each group) were observed only in fasted rats.The blockade of PL CB1 receptors inhibited food intake in fasted animals, suggesting that the PL endocannabinoid system modulated food intake behavior and satiation.FINANCIAL SUPPORT: FAPESP
Neonatal Growth Restriction Heightens Leptin‐Evoked Arterial Blood Pressure and Renal Sympathetic Nerve Responses in Adult Mice
Authors: Peotta Veronica , Morgan Donald , Rahmouni Kamal , Movva Vani , Volk Kenneth , Roghair Robert 
Published: June 2021

Neonatal growth restricted (GR) mice are leptin deficient and obesity resistant, but have adult hypertension, potentially due to enhanced central leptin sensitivity. We hypothesized that neonatal GR increases hypothalamic leptin receptor expression and leptin‐triggered sympathetic activation in adult mice. C57 male mice were fostered in litters of 12 (GR) or 6 (Ctrl), and GR was confirmed by weanling weights below the 10th percentile. At 12 wks, arterial pressure by radiotelemetry (BP) or renal sympathetic nerve activity (RSNA) were measured at baseline and following saline or leptin administration. Compared to normal weight controls, adult GR mice had significantly increased leptin receptor mRNA expression within the arcuate nucleus of the hypothalamus (ARC), decreased adult food intake (0.09±0.01 vs. 0.13±0.02g/g/d; p<0.05), decreased adult body weight, and exaggerated leptin‐triggered increases in both renal sympathetic nerve activity (29+/‐11 vs. ‐9+/‐6% change from baseline, p<0.01 for GR versus control) and systolic blood pressure (8+/‐3 vs. ‐1+/‐6% change from baseline, p<0.05 for icv leptin versus icv saline in GR mice). By confocal immunofluorescence, this GR‐induced leptin hyperresponsiveness was associated with enhanced leptin‐stimulated STAT3 activation within ARC POMC‐positive neurons. We conclude that neonatal GR‐associated leptin deficiency leads to enhanced ARC leptin sensitivity with subsequent hypertension and renal sympathetic hyperactivity.R01 HL102659
Inflammation Enhances Spinal BDNF‐Induced Phrenic Motor Facilitation
Authors: Agosto Ibis , Mitchell Gordon 
Published: June 2021

Long‐lasting phrenic motor facilitation (pMF) can be elicited by multiple, distinct cellular mechanisms. For example, acute intermittent hypoxia triggers a form of pMF known as phrenic long‐term facilitation (pLTF); pLTF requires new synthesis of brain derived neurotrophic factor (BDNF) and activation of its high affinity receptor (TrkB) in the cervical spinal cord (Baker‐Herman et al. 2004). Since systemic inflammation abolishes AIH‐induced pLTF (Huxtable et al. 2013), we tested the hypothesis that the functional impairment is upstream from BDNF/TrkB signaling by testing the impact of systemic inflammation on pMF elicited by cervical spinal injections of BDNF. We assessed phrenic nerve activity before and after intrathecal C4 BDNF (100ng, 12uL) injections in anesthetized, paralyzed and ventilated adult rats 24 hrs post‐LPS (100ug/kg, i.p.) or control (saline) injections. To our surprise, LPS pretreatment enhanced BDNF‐induced pMF (LPS: 105% baseline; versus control: 58% baseline; both n=4; p < 0.05). These results enable twoConclusions1) LPS induced inflammation most likely impairs AIH‐induced pLTF upstream from BDNF/TrkB signaling; and 2) unknown downstream mechanisms attempt to compensate, enhancing the BDNF/TrkB induced pMF. These conclusions advance our understanding concerning the impact of even mild inflammation on important forms of spinal respiratory motor plasticity.[Supported by: NIH HL111598]
Differential Focal Adhesion Kinase (FAK) Expression Accounts for the Developmental Regulation of Pulmonary Artery Endothelial Cell(PAEC) Barrier Function
Authors: Ying Lihua , Barnes Elizabeth , Alvira Cristina , Cornfield David 
Published: June 2021

ObjectiveDeferential FAK expression accounts for the developmental regulation of PAEC Barrier FunctionMethodsLung injury was induced in 6day old (neonatal) and 8week old (adult) mice by Intraperitoneal injection of lipopolysaccharide (LPS) administration. Evans Blue Dye (EBD) was injected in the retro‐orbital sinus vein 24h after LPS, and optical density (OD) of EBD measured in mouse lungs. Barrier function in vitro was assessed in PAEC from neonatal and adult mice using Electric Cell‐substrate Impedance Sensing (ECIS). Gene expression and cytokine profile were evaluated using microarray analysis. FAK expression and gap junction of VE‐Cadherin immuno‐staining were assessed in PAEC with/without FAKsiRNA.ResultsIP LPS increases lung permeability more in adult, than in neonates. With LPS, barrier function is more well preserved in neonatal, compared to adult PAEC. With LPS, FAK mRNA and protein expression increases more in neonatal, than in adult, PAEC. VE Cadherin membrane localization persists longer in neonatal, than in adult PAEC after LPS. VE cadherin membrane expression was decreased in the adult after 24h FAKsiRNA PAEC transfection. Pharmacologic FAK inhibition compromises barrier function more in adult than in neonatal PAEC. With LPS, adult PAEC FAK overexpression improves and depletion worsens barrier function.ConclusionsIn response to injury, PAEC barrier function is more well preserved in neonatal, compared to adult lungs. Deferential expression FAK may account for superior barrier function in neonatal PAEC and, perhaps, the survival advantage for children with ARDS. This observation may have important implications for novel cell‐based therapies in adults with ARDS.
HIF‐1α Expression is Decreased and Contractility is Enhanced in PASMC from PAH Patients
Authors: Barnes Elizabeth , Chen Chihhsin , Alvira Cristina , Cornfield David 
Published: June 2021

OBJECTIVETo determine if hypoxia inducible factor‐1α (HIF‐1α) expression is decreased and myosin light chain (MLC) phosphorylation and contractility are enhanced in pulmonary artery smooth muscle cells (PASMC) from patients with pulmonary arterial hypertension (PAH).METHODSPASMC were isolated from patients diagnosed with PAH and controls. PASMC were examined by Western, RT‐PCR, and immunofluorescence to assess HIF‐1α and phosphorylated MLC levels. Prolyl‐hydroxylase domain (PHD) activity was examined by oxygen, iron (II) and ascorbate cellular content. Metabolism was assessed via formazan and lactate production. The relative contractile response was determined by collagen gel assay. Rho kinase and myosin light chain kinase (MLCK) activities were quantified by ELISA. Ca2+ imaging was employed to assess intracellular Ca2+ levels in HIF‐1α‐/‐ PASMC.RESULTSIn PAH SMC, HIF‐1α protein expression is decreased and MLC phosphorylation is increased. PHD inhibition increases HIF‐1α expression in PAH SMC. Furthermore, cellular oxygen and ascorbate levels are higher in PAH SMC. Formazan production is increased and lactate production is decreased in PAH SMC. The relative SMC contractile response is greater in PAH. MLCK activity is increased in PAH SMC. Loss of HIF‐1α in PASMC potentiates the hypoxia‐induced increase in cytosolic Ca2+.CONCLUSIONSIn PASMC from patients with PAH, HIF‐1α protein expression is decreased and MLC phosphorylation and functional contraction are increased via MLCK activation. Overall, these results demonstrate that PASMC contractility is increased in PAH, perhaps as a direct result of decreased HIF‐1α expression. Altered HIF‐1α expression may play an etiologic role in the development of PAH.
Supervised and Unsupervised Learning Methods for the Automation of Glomerular Scoring
Authors: Bukowy John , Evans Louise , Broadway Elizabeth , Dayton Alex , Cowley Allen 
Published: June 2021

A single rat kidney can contain in excess of 30,000 glomeruli whose function is to act as a filter at the initial interface between the bloodstream and tubular fluid. Sufficient damage to glomeruli and their surrounding Bowman's space leads to altered fluid handling within the kidney and disease states. Scoring of glomeruli from histological preparations with Gomori's One‐Step Trichrome staining can quantify glomerular damage but requires a tedious and time consuming process of manual scoring individually selected glomeruli.In order to decrease inter/intra‐observer variability, analysis time, and resource dedication we propose a method of feature selection for the automation of glomerular scoring. The dataset was comprised of over 1,300 previously human‐scored bright‐field 40x histological images of rat glomeruli obtained under varying experimental conditions. The images consisted of glomeruli surrounded by tubular segments. Using an approach that considers the center of mass of salient features from the images, regions containing glomeruli were located and digitally “masked”, or isolated, within individual images. Unsupervised k‐means clustering was then implemented for color segmentation of the masked glomerular region to select features emphasized from trichrome staining. By training with the described feature set, the scores predicted by the classifier were found to be not significantly different than the human observer, thereby automating a subjective workflow while maintaining precision of scores. While the specific feature set construction described here may only be applicable to the scoring of glomerular damage assayed through trichrome staining, this approach may be applied to a variety of histological assays and stains.(HL116264)
Left Ventricle Cardiac Fibroblast Transcriptome Regulation by Aldosterone In Vivo
Authors: Ball Jana , Syed Maryam , Romero Damian 
Published: June 2021

Excess aldosterone (ALDO) causes cardiac hypertrophy, inflammation and fibrosis that lead to cardiac dysfunction. We previously reported that ALDO/SALT time‐dependently modulates left ventricle (LV) transcriptome in vivo. However, the cardiac fibroblast (CF)‐specific transcriptome regulation by ALDO in vivo is unknown. Even the role of CFs in ALDO‐mediated cardiac injury has been questioned.Uninephrectomized male Sprague Dawley rats were treated with ALDO (0.15 µg/h) and SALT (1.0% NaCl + 0.3% KCl) or vehicle for 2 weeks (N=6/group). LV CFs were isolated and CD90+ cells sorted by flow cytometry. Whole genome transcriptome was probed with Rat Gene 2.0‐ST Affymetrix arrays. Gene expression was analyzed with SAM software and DAVID and Ingenuity software used for bioinformatics analysis.Isolated cells were positive for CF markers (Thy1, vimentin, Fsp1, Ddr2) while negative for cardiomyocyte (Tnnt2) and endothelial cell (CD31) markers. ALDO/SALT regulated (FC蠅1.5‐fold, FDR=10) 950 genes (740 UP and 210 DOWN). Upregulated genes were significantly enriched in the following gene ontology categories: immune response (68 genes), cell cycle (52), chemotaxis (22) and migration (32). Surprisingly, downregulated genes were significantly enriched in the gene ontology category “detection of chemical stimulus involved in sensory perception of smell” with 49 distinct GPCR olfactory receptors downregulated.Our results show that the LV CFs are an ALDO target in vivo despite recent controversy in the field. Furthermore, we identified not only novel genes but completely new gene families that are targeted by ALDO in CFs in vivo, suggesting novel therapeutic approaches for patients with excess ALDO‐mediated cardiac injury.