bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Chronic Treatment With Zamicastat on Right Ventricle Pressure Overload in the Rat Monocrotaline Lung Injury Model of Pulmonary Hypertension
Authors: Igreja Bruno , Pires Nuno , Moser Paul , Soares‐da‐Silva Patrício 
Published: November 2023

Pulmonary arterial hypertension (PAH) is defined, foremost, as a plexogenic arteriopathy with subtotal luminal obliteration that increases pulmonary vascular resistance and imposes a hemodynamic stress on the right ventricle (RV) leading to RV hypertrophy and failure that contributes to premature death. There is experimental and clinical evidence that supports a relation between PAH and the sympathetic nervous system (SNS), indicating that PAH can be mediated, at least partly, by SNS hyperactivation. A strategy for the modulation of sympathetic nerve function is to reduce the biosynthesis of norepinephrine (NE) by inhibiting dopamine β‐hydroxylase (DβH), the enzyme that catalyzes the conversion of dopamine (DA) to NE in sympathetic nerves. Here, we evaluated the effect of 18‐day oral treatment with the DβH inhibitor zamicastat on RV pressure overload in the monocrotaline (MCT)‐induced pulmonary hypertension (PH) model in the rat.MCT increased RV systolic pressure (54.7±2.9 vs 32.3±1.0 mmHg, p<0.0001), mean RV pressure (23.9±1.7 vs 16.6±1.1 mmHg, p<0.001), and decreased heart rate (240.0±5.9 vs 285.8±7.6 beats/min, p<0.0001) in vehicle‐treated rats, as compared to pre‐MCT values. Zamicastat treatment prevented the MCT‐induced increase in mean RV pressure (change from baseline: +1.9±1.5 vs +7.4±1.8 mmHg, p<0.05). Likewise, the HR decrease was significantly attenuated in the zamicastat group as compared to the vehicle group (change from baseline: −14.3±9.7 vs −45.8±8.1 beats/min, p<0.05). Chronic zamicastat treatment decreased NE levels (480.5±43.9 vs 712.1±46.5 ng/mg protein, p<0.005) and increased DA levels (533.0±49.7 vs 12.3±2.3 ng/mg protein, p<0.0001) in adrenal gland homogenates of MCT‐treated rats, as compared to vehicle group demonstrating robust inhibition of DβH.In conclusion, the DβH inhibitor zamicastat reverses heart rate and RV pressure changes, two hallmarks of PAH, in the rat MCT lung injury model.Support or Funding InformationThis work was supported by BIAL ‐ Portela & Ca, S.A.
The effects of Caffeic Acid Phenethyl Ester (CAPE) on oxidative stress and hypoxia‐induced cell damage
Authors: Martin Sarah , Castellano Andrew , Uzoaru Chijioke , Lim Jonathan , Carvis Nicholas , Wieczorek Peter , Barsotti Robert , Young Lindon H , Chen Qian 
Published: November 2023

Oxidative stress has been implicated in pathogenesis of hypoxia and ischemia/reperfusion (I/R) injury. In previous studies, we have shown that the antioxidant CAPE exerted cardioprotection in an isolated rat heart I (30 min)/R (60 min) injury model. In this study, we further evaluated the effects of CAPE on oxidative stress and hypoxia‐induced cell damage. We evaluated the inhibition of absorbance in the phorbol 12‐myristate 13‐acetate (30 nM) induced superoxide production spectrophotometrically in isolated rat neutrophils via reduction of exogenous cytochrome C. We found that CAPE (0.5 μM–40 μM; n=4–13) reduced phorbol 12‐myristate 13‐acetate induced neutrophil superoxide release dose‐dependently from 29±3% to 95±2%. In a rat hind limb I (30 min)/R (60 min) model, blood hydrogen peroxide levels serves as an indicator of blood oxidative stress and was measured in real‐time via a hydrogen peroxide microsensor (100 μm) inserted into both femoral veins (one served as sham, the other as I/R). We found that in the control group, I/R significantly increased blood hydrogen peroxide levels to 2.1±0.8 μM relative to the sham limb at 60 minutes reperfusion when saline was given at the beginning of reperfusion (n=5). By contrast, CAPE when given at reperfusion (40 μM, n=5) significantly reduced blood hydrogen peroxide levels from 30 min reperfusion and throughout the rest of experiment (p<0.05). The relative change was −0.4±0.3 μM between the I/R and sham limbs at 60 minutes reperfusion. In H9C2 rat myoblast cells, cobalt chloride simulated hypoxia and induced cell damage. Tetrazolium, which can differentiate metabolically active and inactive cells/tissues, was used to measure cell damage by measuring absorbance at 450 nm. We found that incubation of cobalt chloride (800 μM, n=8) for 24 hr induced 55±5% cell death. By contrast, pretreatment of CAPE (0.5 μM–10 μM; n=1–3) for 24 hr dose‐dependently improved cell survival up to 30±9% relative to cobalt chloride treatment. In summary, this study suggests that CAPE attenuates oxidative stress from neutrophils and I/R, which may contribute to improvement in cell survival under hypoxia conditions.Support or Funding InformationThis study was supported by Division of Research and Department of Bio‐Medical Sciences at Philadelphia College of Osteopathic Medicine.
Transcriptomic Analysis of the Stellate Ganglion After MI
Authors: Bayles Richard , Olivas Antoinette , Gardner Ryan , Burchard Julja , Habecker Beth 
Published: November 2023

Survivors of a myocardial infarction (MI) remain at serious risk of sudden cardiac death due to lethal arrhythmias. It is known from studies in humans and dogs that electrical and structural remodeling of the stellate sympathetic neurons occurs following MI, including an increase in size and excitability. Increased excitability may be due to a variety of sources including increased dendritic field size, more synaptic inputs or altered ion channel expression to name a few. In an effort to identify neuronal genes regulated by MI, we have performed RNA sequencing (RNAseq) of RNA extracted from the stellate ganglia of mice 14 days after MI or sham surgery. Infarction was induced by 45 min occlusion of the left anterior descending coronary (LAD) artery, and sham operated animals underwent the same procedure with no occlusion. After 14 days, left ventricular scar tissue was visible in the occluded animals, and gene expression changes in the infarct and borderzone were in agreement with previous studies of MI. Library preparation was completed using the TruSeq Stranded Total RNA kit (Illumina), and sequencing using the Illumina HiSeq 2500 Sequencer. Sequence alignment and QC was performed using STAR. RNA expression across all samples was highly consistent, however small yet consistent changes in the expression of genes were detected between mice with MI and controls. These changes included genes encoding ion channels, receptors, synaptic proteins and actin remodeling proteins.Support or Funding InformationThis work was supported by NIH RO1 HL093056
Comparison Between Spectral Analysis and Symbolic Dynamics for Heart Rate Variability Analysis in the Rat
Authors: Silva Luiz Eduardo Virgilio , Geraldini Victor Rezende , Oliveira Bianca Potratz , Silva Carlos Alberto Aguiar , Salgado Helio Cesar , Fazan Rubens 
Published: November 2023

Although spectral analysis has been widely used to assess the autonomic control of the heart, several issues are still in debate about its interpretation, especially in experimental animals such as rats and mice. A nonlinear alternative method, namely symbolic dynamics, was proposed and has been reported to be very useful to represent sympathetic and parasympathetic modulation to the heart. However, studies evaluating the validity of symbolic dynamics in experimental models still lack. Conscious male Wistar rats, under continuous recording of electrocardiogram (ECG) or arterial pressure (AP), were subjected to autonomic imbalance by two protocols: pharmacological blockade of adrenergic or cholinergic muscarinic receptors administration (atenolol 4 mg/kg or methylatropine 2 mg/kg, iv, N=9 in each group) and reflex changes in sympatho‐vagal balance by AP changes elicited by phenylephrine (PHE, N=9) or sodium nitroprusside (NPS, N=9). Beat by beat series of cardiac interval (CI) were generated from ECG or AP recordings and both spectral analysis and symbolic dynamics were calculated for each animal. Spectra of CI series were calculated by FFT and integrated in low‐ (LF: 0.2–0.8Hz) and high‐frequency bands (HF: 0.8–3Hz). For symbolic analysis, symbols were attributed to CI values and sequences of 3 symbols were classified as 0, 1 or 2V according to the number of variations showed. Percentage of 0V and 2V are associated to sympathetic and vagal cardiac modulation, respectively. Hypertensive response caused by PHE (33 ± 3 mmHg) led to a reflex bradycardia (−45 ± 3 bpm) while hypotension due to NPS (−15 ± 1 mmHg) was accompanied by tachycardia (46 ± 6 bpm). The administration of atenolol and atropine led to a reduction and an increase in HR, respectively (−19 ± 6 and 70 ± 8 bpm). All drugs used reduced the total variability (standard deviation) of the CI series. The results of the spectral and symbolic analysis are showed in the table at the end. The symbolic dynamics proved to be more robust than the spectral analysis for the evaluation of the autonomic control in rats. The 1V family patterns, hitherto unknown, have been shown to be linked to sympathetic modulation in the rat and should be considered in future studies.Support or Funding InformationFapesp

basal
atenolol
basal
atropine
basal
NPS
basal
PHE

LF (nu)
35±2
23±4*
40±4
28±4*
9.8±2.1
14±4
11±2
9.3±2.0

HF (ms2)
6.0±0.8
2.7±0.9*
4.3±0.4
0.2±0.03*
10±2
6.3±1.5*
4.2±1.0
25±6*

0V (%)
27±2
16±3*
27±3
29±4
7.7±1.4
9.1±1.7
9.0±1.4
5.6±1.2

1V (%)
44±1
38±2*
42±1
46±2
35±2
40±1*
45±2
33±2*

2UV (%)
25±2
37±4*
26±2
19±1*
50±3
43±2*
39±3
51±4*

P<0.05 compared to basal.
The Effect of a Patent Foramen Ovale on Ventilatory Responses to Hypoxia
Authors: Chang Alex J , Boulet Lindsey M , Davis James T , Hardin Alyssa M , Foster Glen E , Lovering Andrew T 
Published: November 2023

Approximately 35% of the general healthy population has a patent foramen ovale (PFO) (Woods et al., 2010; Marriott et al., 2013; Elliott et al., 2013). Previous work by our lab has shown that after 16 days of exposure to 5260 m, subjects with a PFO (PFO+) had blunted ventilatory acclimatization to high altitude compared to subjects without a PFO (PFO−), such that PFO+ subjects had a lower PaO2, higher PaCO2, and lower SaO2 (Elliott et al., J Appl Physiol, 2015). However, in that study 7/11 PFO+ subjects were female whereas only 2/10 PFO− subjects were female and thus potential sex differences were not accounted for and it is known that sex hormones can affect ventilatory responses to O2 and CO2 (Schoene et al., 1986; Slatkovska et al., 2006). Thus, it remains unknown if PFO+ subjects exhibit blunted ventilatory responses to hypoxia compared to PFO− subjects, independent of sex. Therefore, the purpose of this study was to determine if the presence of a PFO affects ventilatory responses during acute exposure to either poikilocapnic hypoxia or isocapnic hypoxia.A total of 31 healthy, non‐smoking subjects matched for height, weight, sex and age completed the entire study:PFO+: age: 24 ± 5 yrs, height: 170 ± 11 cm, weight: 69 ± 14 kg, BSA: 1.8 ± 0.2 m2PFO−: age: 27 ± 9 yrs, height: 172 ± 10 cm, weight: 71 ± 16 kg, BSA: 1.8 ± 0.2 m2These 31 subjects included 15 PFO+ subjects (8 female) and 16 PFO – subjects (8 female). On the day of the test, the subjects came to the lab on a single visit and breathed 1) poikilocapnic hypoxia (PETO2 = 51.4 ± 6.5 mmHg) and 2) isocapnic hypoxia (PETO2 = 43.7 ± 4.4 mmHg, PETCO2 = 40.0 ± 3.4 mmHg), and these gases were administered using the AirForce breathing response system in a randomized and balanced order. Time points of interest were baseline resting ventilation while sitting comfortably in a chair and the time at which VE was greatest after 5 minutes of breathing the respective hypoxic gas. There was a 40 min break between hypoxia trials. Hypoxic ventilatory response (HVR) was calculated as the change in minute ventilation divided by the change in saturation (Δ VE/Δ SpO2).There was no effect of PFO on HVR during exposure to either isocapnic hypoxia or poikilocapnic hypoxia (p > .05). There was no effect of PFO on SpO2, VE, VT, RR, PETO2 or PETCO2 during either the isocapnic hypoxia or poikilocapnic hypoxia trials (p > .05). These data suggest that HVR is not blunted in PFO+ subjects compared to PFO− subjects. Additionally, there were no sex differences in HVR in PFO+ subjects compared to PFO− subjects. Based on these findings, it is plausible that the blunted ventilatory acclimatization previously found by our group may be due in part to differences in responses to hypercapnia suggesting involvement of a central chemoreceptor rather than just a peripheral component (see accompanying poster Hardin et al 2016).
Ventilatory, metabolic and thermal responses to hypercapnia and hypoxia in orchidectomized and testosterone replaced adult male Wistar rats
Authors: Marques Danuzia A , de Carvalho Debora , da Silva Glauber SF , Scarpellini Carolina da S , Bícego Kênia C , Szawka Raphael E , Gargaglioni Luciane H 
Published: November 2023

Elevated plasmatic concentrations of Testosterone (T) may have an impact over respiratory parameters. Therefore, we evaluated the influence of T on ventilation (VE) and oxygen consumption (VO2) during room air, hypercapnia (7%CO2) and hypoxia (7%O2) in adult male Wistar rats. VE measurements were obtained using the barometric method (whole body plethysmography) and VO2 by closed respirometry system in intact and orchidectomized animals treated with vehicle (corn oil, ORX group; 0.2 mL/rat, s.c.) or T propionate (ORX+T group; 0.25 mg/0.2 mL/rat, s.c) for seven days. Orchiectomy did not affect ventilatory, metabolic and thermal responses to hypercapnia and hypoxia in rats. T replacement caused an increase in ventilatory response to hypercapnia (VE/VO2‐intact: 87.2 ± 9.8; ORX: 78.9 ± 13.3 and ORX+T: 124.4 ± 21.7) and to hypoxia (VE/VO2‐intact: 96.7 ± 17.5; ORX: 85.1 ± 16.1 and ORX+T: 119.5 ± 18.2). Our data suggest that T exerts an excitatory modulation in central and peripheral chemoreflex.Support or Funding InformationFAPESP and CNPq
Dynamic characteristics of respiratory central chemoreflex in normal rats
Authors: Tohyama Takeshi , Saku Keita , Tsutsui Hiroyuki , Sunagawa Kenji 
Published: November 2023

BackgroundCentral chemoreflex is the dominant regulator of respiration. Central chemoreceptors are located on the ventral surface of the medulla, respond primarily to changes in arterial carbon dioxide content (PaCO2). It is well known that increasing in PaCO2 linearly increases minute ventilation (VE) and increasing in VE decreases PaCO2 with hyperbolic manner. Thus, central chemoreflex consists of a negative feedback loop to maintain PaCO2 around 40 mmHg. Although the static characteristics of central chemoreflex have been well examined in both animals and human, the dynamic characteristics, which is prerequisite to understand how quickly and how stably central chemoreflex operates to regulate ventilation and PaCO2, has not been elucidated. The purpose of this investigation is to characterize the dynamic characteristics of central chemoreflex control of ventilation and PaCO2 with a system identification techniques based on a white noise approach.MethodsWe divided the central chemoreflex system into two components: central controller (EtCO2‐VE relationship) and peripheral plant (VE‐EtCO2 relationship) (Fig. 1). In eleven anesthetized rats, we measured respiratory end tidal CO2 (EtCO2) as a surrogate of PaCO2, and VE. To estimate central controller, we randomly switched inhaled gas from 0% to 5% CO2 every 10 sec for an hour and recorded spontaneous VE (Fig. 2A). To evaluate the peripheral plant, we randomly switched VE from hypoventilation to hyperventilation every 0.8 sec for an hour and simultaneously recorded EtCO2 under mechanical respiratory condition (Fig. 2B). We calculated the transfer functions of central controller and peripheral plant in the frequency domain.ResultsThe gain of central controller was flat up to 0.005 Hz and then decreased with frequencies. The phase was in phase at the lowest frequency and gradually delayed in higher frequencies (Fig. 3A). In the peripheral plant, the gain gradually decreased from the lowest frequency to 0.1Hz and then sharply decreased. Its phase has out of phase at the lowest frequency and gradually delayed in higher frequencies (Fig. 3B). Transfer functions of both subsystems represented as a low‐pass filter characteristic with dead time. High coherence values suggested that the input‐output relationships of the central controller and peripheral plant were predominately governed by this framework.ConclusionsWe characterized the dynamic properties of the central controller and peripheral plant of the central chemoreflex in normal rats with the white noise system identification method. These systematic analysis of chemoreflex dynamics would help us understand the respiratory regulation in physiological condition.
Implication of the Histone Deacetylase 6 in pulmonary arterial hypertension
Authors: BOUCHERAT Olivier , CHABOT Sophie , PAULIN Roxanne , TRINH Isabelle , BOURGEOIS Alice , POTUS François , LAMPRON Marie‐Claude , LAMBERT Caroline , BREUILS‐BONNET Sandra , PARADIS Renée , NADEAU Valérie , GONCAROVA Elena , PROVENCHER Steeve , BONNET Sébastien 
Published: November 2023

RATIONALEPulmonary arterial hypertension (PAH) is a vascular remodeling disease of complex etiology. Despite environmental stressful conditions, pulmonary artery (PA) smooth muscle cells (PASMCs) and endothelial cells (PAECs) exhibit a pro‐proliferative and anti‐apoptotic phenotype. Histone deacetylase 6 (HDAC6) is a cytoplasmic histone deacetylase overexpressed in response to stress and implicated in the regulation of multiple pro‐survival mechanisms in cancer cells. Therefore, we hypothesized that HDAC6 expression is increased in PAH‐PASMCs and PAH‐PAECs allowing them to survive and proliferate, thus contributing to vascular remodeling in PAH.OBJECTIVEUsing a multidisciplinary and translational approach we aimed to demonstrate that HDAC6 inhibition is a promising strategy to improve PAH.METHODS AND RESULTSHDAC6 is significantly up‐regulated (immunoblot) in lungs, distal PAs, and isolated PASMCs and PAECs from 10 PAH patients and 15 experimental PAH animal (5 Sugen/hypoxia rats; 5 monocrotaline rats and 5 chronic hypoxic mice) compared to controls. Molecular (siRNA) and pharmacological inhibition (Tubastatin and ACY‐775) of HDAC6 reduces dose‐dependently PAH‐PASMC/PAEC proliferation (Ki67 assay) and resistance to apoptosis (Annexin V assay) in vitro sparing control cells. Mechanistically, we demonstrated that HDAC6 deacetylates Ku70, blocking the translocation of Bax to mitochondria and preventing apoptosis. In vivo inhibition of HDAC6 (Tubastatin A 25mg/kg/day for 2 weeks) significantly improved (n=5 to 10 p<0.05) established PAH by decreasing mean PA pressure, total pulmonary resistance and increasing cardiac output in two experimental models (Sugen/hypoxia and monocrotaline). In addition, we showed that HDAC6 inhibitor can be safely given in combination with currently approved PAH therapies (macitentan and tadalafil). Finally, Hdac6 K.O mice have significantly lower right ventricle systolic pressure in response to 3 weeks of chronic‐hypoxia compared to wild‐type mice.CONCLUSIONWe showed for the first time that HDAC6 is implicated in PAH development and represents a new promising therapeutic target to improve PAH.Support or Funding InformationNone
Implication of the transcription Factor FOXM1 in pulmonary arterial hypertension
Authors: BOUCHERAT Olivier , TRINH Isabelle , LAMBERT Caroline , POTUS François , BREUILS‐BONNET Sandra , NADEAU Valérie , PAULIN Roxanne , PROVENCHER Steeve , BONNET Sébastien 
Published: November 2023

RATIONALEPulmonary Arterial Hypertension (PAH) is a disease of the pulmonary vasculature, defined by an elevated pulmonary vascular resistance, leading to right heart failure and premature death. PAH is characterized by enhanced pulmonary artery smooth muscle (PASMC) proliferation and suppressed apoptosis within pulmonary artery (PA) wall. Targeting the cancer‐like of PASMCs represents an attractive therapeutic avenue to tackle PAH. Overexpression of the transcription factor FOXM1 has been shown to be a key driver of cancer progression through the stimulation of DNA repair, cell proliferation and cell survival.OBJECTIVEUsing a multidisciplinary and translational approach we aimed to demonstrate that up‐regulation of FOXM1 in PAH‐PASMCs triggers proliferation and resistance to apoptosis.METHODS AND RESULTSFOXM1 is significantly increased (immunoblot and immunofluorescence) in lungs, distal PAs, and isolated PASMCs from PAH patients as well as in the monocrotaline (MCT)‐induced PAH model compared to controls. We demonstrated that, in response to growth factors like PDGF and IGF1, Akt is activated (increased P‐Akt), phosphorylates FOXO3a and inhibits it, allowing the up‐regulation of FOXM1. Moreover, we found that inhibition of FOXM1 in PAH‐PASMCs increases DNA damage (gH2AX) and reduces expression of NBS1 and PLK1 (immunoblot), two factors up‐regulated in PAH‐PASMCs (immunoblot and immunofluorescence) and involved in DNA repair and cell cycle progression. Consistently, pharmacological inhibition of FOXM1 using Thiostrepton dose‐dependently reduces PAH‐PASMC proliferation (Ki67 labeling) and resistance to apoptosis (Annexin V assay) in vitro. Inhibition of FOXM1 with Thiostrepton improves established PAH (right heart catheterization) in the MCT model.CONCLUSIONWe showed for the first time that FOXM1 is overexpressed in human PAH and implicated in the pro‐proliferative and anti‐apoptotic phenotype of PAH‐PASMCs.Support or Funding InformationNone