bluuebunny/crossref_metadata_2025 huggingface dataset:
Detrimental Effects of Nearby Construction Activity on Endothelial and Vascular Smooth Muscle Function in Cerebral Arteries of Sprague‐Dawley (S‐D) Rats
Authors: Lombard Julian H. , Terashvili Maia , Kozak Kaleigh , Gifford Alison , Uche Nnamdi , Allen Linda Adrienne , Gebremedhin Debebe
Published: June 2021

The present study assessed the effect of nearby construction activity on endothelium‐dependent vasodilation to acetylcholine (ACh), a crucial diagnostic test, in middle cerebral arteries (MCA) of male Sprague‐Dawley (S‐D) rats. Construction activity began on October 2, 2017 and consisted of installing a utility tunnel for a new heating system near the MCW basic science building, followed by additional construction in front of the adjacent medical education building. The project involved extensive digging and tunneling, and the use of heavy equipment (steam shovels, bulldozers, dump trucks, front end loaders, etc.). Various construction activities continued until the end of May 2018. Most of the construction activity generated high levels of vibration and noise in the patio area just outside the MCW Biomedical Resource Center, which houses numerous rodents and other species used in research projects at the institution. Vibrations were monitored using a system (RPi) designed in our laboratory and consisting of a small computing unit attached to a rolling sensor (low sensitivity) and a Piezo Film Sensor (high sensitivity). The sensor was placed in an empty rat cage and vibrations were quantified as Hz. During the construction period, normal endothelium‐dependent vasodilation in response to ACh was abolished or dramatically reduced in isolated MCA of S‐D rats fed a normal salt diet. MCA from rats studied after completion of construction but housed in the vivarium during construction showed a partial recovery of ACh‐induced dilation, but MCA responses to ACh and vascular NO sensitivity, assessed via vasodilator responses to the NO donor sodium nitroprusside (SNP), in those animals were significantly reduced compared to rats obtained, housed, and studied after completion of the construction project. In separate experiments, activity of Ca2+‐activated maxi K+ channels was lost in isolated cerebral artery smooth muscle cells from S‐D rats housed and studied during the construction period. During the construction period, the RPi system recorded high levels of vibration that corresponded to construction activity outside the building. Following cessation of construction, baseline levels of vibration returned and endothelium‐dependent vasodilation to ACh and vessel NO sensitivity recovered to normal levels. The results of this study show that the noise and vibration associated with nearby construction can have highly deleterious effects upon crucial physiological phenotypes.

Support or Funding Information

NIH #R01‐HL128242

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Single‐cell Measurement of Red Blood Cell Oxygen Delivery Rate
Authors: Kim Sangho
Published: June 2021

Oxygen (O2) is supplied throughout the body by hemoglobin (Hb) bounded in red blood cells (RBCs). The ability of RBCs to deliver O2 has been routinely assessed by P50 using clinical hematology analyzers, defined as the partial pressure of O2 (PO2) required to saturate the Hb in RBCs to 50%. Although this defines the ability of RBCs to carry O2 under equilibrium states, it cannot determine the efficacy of O2 delivery in the dynamic blood flow, which could occur over the span of ~3 s in the microcirculation. Furthermore, while various factors such as pH, temperature and 2,3‐diphosphoglycerate (2,3‐DPG) affecting the O2 dissociation curve (ODC) and P50 have been established, it is unclear how, and the variations of these factors, may influence the RBC O2 delivery on the cellular level. Therefore, in this study, we developed a microwell array oxygen‐sensing chip for measuring the rate of O2 delivery from RBCs at a single‐cell level. Washed RBCs were re‐suspended in an oxygen‐sensitive fluorescence dye solution (ruthenium tris(2,2′‐dipyridyl) dichloride hexahydrate, RTDP) and introduced into the microfluidic device. After trapping of single RBCs in the microwells, heavy mineral oil is used to flush excess RBCs and to isolate single RBCs in the microwell array. Subsequently, the fluorescence intensity of the oxygen‐sensitive dye in the microwell was measured as it gets deoxygenated by N2 gas separated by a PDMS membrane. RTDP fluorescence is quenched in the presence of O2, the fluorescence intensities in the microwells increase as they get deoxygenated by the continuous flow of N2 gas. The rate of O2 release from the single RBC trapped in the microwells, however, would alter the rate of change of microwell PO2. Accordingly, RBCs with higher rates of O2 release would reduce the overall rate of deoxygenation in the microwell, thus reducing the rate of decrease in the PO2. To demonstrate the sensitivity of the device, we deoxygenated the microwells containing RBCs and RBC ghosts (RBCs without Hb). As expected, the PO2 in the microwells containing RBCs was significantly higher (p < 0.0001) than that containing RBC ghosts, due to O2 release from Hb bounded in the RBCs. Additionally, we investigated the potential difference in the O2 delivery rate between density‐fractionated young (top 5% fraction) and old RBCs (bottom 5% fraction). The obtained results showed an apparent difference in the PO2 in microwells with young and old RBCs is statistically significant (p < 0.0001), suggesting that senescent RBCs have a lower O2 delivery rate.

Support or Funding Information

NMRC/CBRG/0078/2014 and Biomedical Institute for Global Health Research and Technology

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Dopamine Regulates Blood‐Brain Barrier Endothelial Cell Hyperpermeability
Authors: Kosel Kelby , Shaji Chinchusha Anasooya , Zemmedhun Gelilla , Tharakan Binu
Published: June 2021

Blood‐Brain Barrier (BBB) dysfunction leading to hyperpermeability is one of the major causes of brain edema following conditions such as traumatic and ischemic brain injury. The BBB consists of microvascular endothelial cells that are linked to each other by tight junction and adherens junction proteins and are intracellularly linked to actin cytoskeletal assembly of the cell mainly via zonula occludens‐1 (ZO‐1). Recent studies suggest that the activation of the NLRP3 inflammasome pathway has a major role promoting various pathologies associated with brain injury. An inflammasome is a multiprotein complex that is responsible for the activation of inflammatory responses in the body. Recent studies show that the neurotransmitter, dopamine (DA) is an inhibitor of this pathway. Dopamine regulates bodily functions such as movement, behavior and many systemic functions, but also connects the nervous and immune system in the body. In this study we investigated the effects of DA for its protective effect against oxidative stress‐induced BBB dysfunction and hyperpermeability. In the experiments, hydrogen peroxide (H2O2) was used to induce oxidative stress in rat brain microvascular endothelial cells. Oxidative stress due to increased reactive oxygen species (ROS) formation occurs following trauma and ischemia. Rat brain microvascular endothelial cell monolayers were exposed to H2O2 alone (100μM; 2 hour) or in presence of DA (10μg/ml; 30min) or dopamine D1 receptor agonist (A68930; 10μg/ml; 30min). The changes in tight junction integrity and cytoskeletal assembly were studied using ZO‐1 and β‐catenin immunofluorescence and rhodamine phalloidin staining for F‐actin respectively. Cell viability was studied using Calcein AM cell viability assay. Changes in the formation ROS were studied using 2′, 7′‐dichlorofluorescien diacetate. H2O2 (100μM) treatment resulted in significant increase in monolayer permeability (p<0.05), ROS formation (p<0.05), disruption of the endothelial tight/adherens junctions and induced F‐actin stress fiber formation. Dopamine and A68930 treatment resulted in a decrease in H2O2‐induced monolayer hyperpermeability significantly (p<0.05). Furthermore, DA protected tight junction integrity and actin cytoskeletal assembly. DA and A68930 had no effect on H2O2‐induced ROS formation. The cell viability assay showed that H2O2‐induced barrier disruption is independent of cell death. Our results suggest that one of the major mechanisms for DA‐mediated protection against barrier dysfunction/hyperpermeability may be mediated via inhibiting the NLRP3 inflammasome pathway and not by inhibiting increased ROS formation.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Fibulin‐4 and Lysyl Oxidase Cooperate to Maintain Arterial Wall Integrity in Large but not Small Vessels
Authors: Halabi Carmen M. , Lin Michelle , Broekelmann Thomas J. , Mecham Robert P.
Published: June 2021

Fibulin‐4 (FBLN4) is an extracellular matrix protein essential for elastic fiber assembly in large conduit arteries. While its exact role in the process remains unknown, it is hypothesized that, through binding lysyl oxidase (LOX), FBLN4 facilitates elastin crosslinking and mature elastic fiber formation. To assess whether FBLN4 and LOX interact in the process of elastic fiber formation in vivo, we took a genetic approach where we bred recently characterized mice carrying a disease‐causing mutation in Fbln4 (Fbln4E57K) with LOX insufficient (Lox+/−) mice and examined the consequences of LOX insufficiency on the cardiovascular system of Fbln4E57K mice. By 3–4 months of age Fbln4E57K;Lox+/− mice were similar in size to Fbln4E57K mice and littermates. Ascending aortic aneurysms, which were incompletely penetrant and confined to the ascending aorta in Fbln4E57K mice were significantly worsened by LOX insufficiency as they were fully penetrant and extended from the aortic root through the aortic arch in Fbln4E57K;Lox+/− mice. Additionally, arterial tortuosity and elastic fiber fragmentation of large conduit arteries were exacerbated by LOX insufficiency. Interestingly, muscular arteries remained intact. Fbln4E57K;Lox+/− mice had significant cardiac hypertrophy and widening of the pulse pressure that was due to lower diastolic blood compared to Fbln4E57K mice. The cardiac hypertrophy and decrease in diastolic blood pressure are likely a consequence of worsened aortic regurgitation as large artery stiffness was not exacerbated by LOX insufficiency in Fbln4E57K mice. In summary, LOX insufficiency exacerbated the vascular phenotype seen in mice with mutant FBLN4 suggesting that there is a functional interaction between the two molecules. Interestingly, elastic fiber formation was unaffected in muscular arteries raising the possibility that the process of elastic fiber assembly, previously thought to be the same in all elastic tissues, may differ between vascular beds.

Support or Funding Information

NIH, NHLBI ‐ 1K08HL135400

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Cerebral Blood Flow Ultrasonography as a Diagnostic Tool for Monitoring Recovery from Concussion in Children and Adolescents
Authors: Favre Michelle E , Breen Paul P , Browne Gary J , Fyffe Andrew , Magalhaes Jennifer , Serrador Jorge M
Published: June 2021

Approximately 70% of concussions are sports‐related, accounting for up to 1.9 million children and adolescents in the USA every year. Despite the high rates of injury, there are currently no consistent agreements regarding objective measures of diagnosis or severity of injury. Our pilot study determined whether cerebral blood flow (CBF) in the internal carotid artery can be utilized as an objective marker of concussion and recovery trajectory in concussed children and adolescents. We recruited individuals being seen at a concussion clinic with post concussive symptoms (mean= 40 ± 31 days post injury; range= 8–101 days) vs a group of controls who were being seen at the clinic for musculoskeletal injury. Concussed (n=10, 7 male; 12 ± 3 years) and healthy controls (n=8, 5 male; 13 ± 2 years) underwent ultrasound assessments of internal carotid artery blood flow during resting conditions when seated and supine. Continuous blood pressure, ECG, and end‐tidal CO2 were also obtained in participants. Preliminary results showed a trend for an increase in CBF in concussed children when seated (concussed= 644 ± 167 ml/min vs control= 535 ± 118 ml/min; p=0.122) but not when supine (concussed= 628 ± 142 ml/min vs control= 602 ± 140 ml/min; p=696). When comparing the percent of supine CBF when seated, concussed children showed a trend for greater CBF (concussed= 104 ± 19% vs control= 90 ± 11% p=0.101). Interestingly, in our 10 concussed participants, the ratio of seated to supine CBF negatively correlated with the number of days since injury (r= −0.738; p=0.015), suggesting elevated seated CBF may be returning towards normal values. There were no differences in end‐tidal CO2 between concussed and controls when seated (concussed= 40.4 ± 3.0 mmHg vs control= 40.8 ± 3.3 mmHg) or supine (concussed= 40.4 ± 3.8 mmHg vs control= 41.1 ± 3.8 mmHg). However there was significantly increased mean arterial pressure in controls when supine (concussed= 83.4 ± 4.8 mmHg vs control= 92.4 ± 11.9 mmHg; p=0.036) and a trend when seated (concussed= 86.2 ± 5.2 mmHg vs control= 96.0 ± 12.2 mmHg; p=0.074). If additional subjects follow the same pattern, our preliminary data would suggest that concussed children appear to be hyperperfused when seated. While it is unclear why CBF may be elevated when seated, one possibility is that flow is matching the increased metabolic demand associated with neural remodeling after injury. Our preliminary data supports that ultrasonography may be a useful diagnostic tool to monitor recovery from concussion in children and adolescents when taking into account body posture.

Support or Funding Information

The study was supported by the MARCS Institute for Brain, Behaviour and Development, Western Sydney University, Sydney, AUS.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Neural activity drives dynamic Ca2+ signals in capillary endothelial cells that shape local brain blood flow
Authors: Longden Thomas , Harraz Osama , Hennig Grant , Shui Bo , Lee Frank , Lee Jane , Reining Shaun , Kotlikoff Michael , Kostensis Evi , König Gabriele , Hill‐Eubanks David , Nelson Mark
Published: June 2021

Brain capillaries constitute a vast, arborescent network of microscopic tubes composed of endothelial cells (ECs) that lie in close apposition to all neurons. Capillaries send long‐range electrical signals to regulate arteriolar diameter and control blood flowing into the brain, but it is unknown whether higher resolution control of blood flow exists within the capillary bed. Here, we demonstrate that capillary ECs exhibit recurrent, long‐lasting, high‐amplitude, local Ca2+ signals in vivo that depend on neuronal activity. These signals are mediated by Gq‐protein‐coupled receptors, prominently including prostaglandin E2‐induced activation of the EP1 receptor, and reflect Ca2+ release through endoplasmic reticulum IP3 receptors and Ca2+ entry through TRPV4 channels. EC Ca2+ elevation at capillary branch points relaxes overlying pericytes, which is associated with a nitric oxide‐dependent increase in local blood flow. Capillary and arteriolar ECs respond robustly to neural stimulation, suggesting coordinated Ca2+ signaling in these compartments directs blood flow to satisfy neuronal metabolic needs.

Support or Funding Information

Supported by American Heart Association postdoctoral fellowships and a Scientist Development Grant (14POST20480144; 17SDG33670237 to T.A.L.; 17POST33650030 to O.F.H), the Totman Medical Research Trust (to M.T.N.), Fondation Leducq (to M.T.N.), EC Horizon 2020 (to M.T.N.), and National Institutes of Health (NIH 4P20 GM103644/4‐5 to the Vermont Centre on Behavior and Health (T.A.L); P30‐GM‐103498 to the COBRE imaging facility at the University of Vermont College of Medicine; R24‐HL‐120847 to M.I.K; P01‐HL‐095488, R01‐HL‐121706, R37‐DK‐053832 and R01‐HL‐131181 to M.T.N., and FOR2372 to G.M.K and E.K).

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Comparison of Non‐Invasive Peripheral Vascular Function to Invasive Measures of Coronary Function in Patients with Suspected Coronary Microvascular Dysfunction
Authors: Nardone Massimo , Miner Steven , McCarthy Mary , Edgell Heather
Published: June 2021

Introduction

The purpose of this study is to compare non‐invasive vascular assessments to invasive gold standard measures of coronary flow and resistance in patients with suspected coronary microvascular dysfunction (CMD), a condition driven by systemic endothelial dysfunction. We hypothesize that non‐invasive measures will be associated with both coronary flow and resistance following pharmacological hyperemia.

Methods

Forty‐one patients with suspected CMD attended the Cardiovascular Integrative Physiology Clinic at Southlake Regional Health Centre. Patients underwent finger‐based arterial tonometry (RHPAT) to non‐invasively quantify microvascular endothelial function (EndoPAT). A subset of participants (n=15) also concurrently completed flow mediated dilation (FMD) of the brachial artery to assess conduit artery endothelial function. Briefly, a standard blood pressure cuff was positioned on the right arm of patients, distal to the elbow joint. Baseline recordings preceded 5 minutes of forearm ischemia, and was followed by cuff deflation, eliciting reperfusion. Within 4 months, patients underwent coronary reactivity testing using the Doppler guidewire method. Specifically, the coronary flow reserve (CFR), and the index of microvascular resistance (IMR) were calculated during pharmacologically‐induced hyperemia using adenosine, then acetylcholine, then dobutamine. Prior to each stimuli, baseline measures were obtained to ensure hemodynamics results to baseline.

Results

RHPAT was negatively correlated to the IMR during dobutamine (r=−0.39, p=0.04), but not the CFR (r=0.14, p=0.49). FMD was negatively correlated to the IMR during adenosine (r=−0.64, p=0.01), but not the CFR (r=0.29, p=0.30). RHPAT and FMD were not correlated to the IMR or CFR during acetylcholine.

Conclusion

These preliminary results suggest that measures of non‐invasive peripheral vascular function can predict pharmacologically induced changes in coronary resistance, but not coronary flow.

Support or Funding Information

St. Jude Medical

The Heart of Gold Cardiac Research Fund

York University

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Ischemia/Reperfusion‐Induced Reduction of Ca2+ Sensitivity in Isolated Cardiomyocytes
Authors: Valencia Sara Osorio , Peirano Felipe , Xi Wang , Han Young Soo , Diaz Rienzi , Sieck Gary
Published: June 2021

Ischemia/reperfusion (I/R) injury occurs during acute myocardial infarction and is a frequent cause of contractile failure, morbidity and mortality. There is evidence that reduced cardiac contractility following I/R injury is associated with disruption of excitation‐contraction (E‐C) coupling. We hypothesized that I/R injury alters E‐C coupling in cardiomyocytes by reducing the Ca2+ sensitivity of contraction.

Cardiomyocytes were isolated from adult rat (Sprague Dawley) hearts using a modified Langendorff system. Cardiomyocytes were then loaded with fura‐2 AM (Ca2+ fluorescent indicator; 1 μM) and electrically stimulated every 2 s (0.5 Hz). Cytosolic Ca2+ concentration ([Ca2+]cyt) and sarcomere length shortening responses to stimulation were simultaneously measured using an IonOptix System equipped with a hypoxia‐regulated incubator system (Live Cell Instrument). To model I/R, cardiomyocytes were initially exposed to normoxia (21% O2) for 30 min followed by 30 min exposure to 2.5% O2 and finally 30 min exposure to normoxia. Throughout the I/R protocol, Ca2+ sensitivity of cardiomyocytes was assessed using a phase loop plot of concurrently measured [Ca2+]cyt and sarcomere length shortening.

I/R reduced the extent of sarcomere length shortening, but it had no effect on the amplitude of evoked [Ca2+]cyt transients. Furthermore, I/R reduced Ca2+ sensitivity reflected by a rightward shift in the phase loop plots. These results support the hypothesis that I/R alters E‐C coupling in cardiomyocytes by reducing the Ca2+ sensitivity of contraction.

Support or Funding Information

Supported by Mayo 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.
Cardiac Function and Exercise Capability in Female Goto‐Kakizaki Type‐2 Diabetic Rats after Myocardial Ischemia/Reperfusion
Authors: Omoto Ana Carolina Mieko , do Carmo Jussara M. , da Silva Alexandre A. , Salgado Mateus C. , Salgado Helio C. , Fazan Rubens , Hall John E.
Published: June 2021

Diabetes mellitus is a major risk factor for coronary artery disease. However, there is conflicting evidence on whether diabetes exacerbates myocardial ischemia/reperfusion (I/R) injury, particularly in females. In this study, we investigated if the deleterious impact of I/R on cardiac function and exercise capability is amplified in female Goto‐Kakizaki (GK, n=6) rats, a model of type‐2 diabetes, 4 weeks after myocardial I/R compared to female Wistar rats (n=5) at 28 weeks of age. Rats were submitted to myocardial I/R by temporary (30 min) ligation of the left anterior descending coronary artery. Long and short axis left ventricle dimensions were obtained before and 4 weeks after I/R procedure using a 21 MHZ transducer (VisualSonics‐VEVO3100®). At the end of week 4, animals were subjected to an aerobic fitness test (maximum velocity test ‐ Vmax) when they were placed on a treadmill, with no inclination, and the speed was increased in steps of 3 m/min every 3 min until animal fatigue. At baseline, female GK rats exhibited higher blood glucose concentration (180±12 vs. 109±4 mg/dL) and lower ejection fraction (63±3 vs. 78±3 %), fractional shortening (18±2 vs. 36±3 %) and cardiac output (75±11 vs. 122±6 mL/min) compared to Wistar controls. At the end of 4 weeks post myocardial I/R, glucose concentration was reduced in GK rats (180 ± 12 to 130 ± 15 mg/dL), associated with a cumulative deficit food intake (~14 g) while no changes were observed in Wistar rats. We also found no alterations in ejection fraction (EF), fractional shortening (FS) or cardiac output (CO) 4 weeks post I/R in female GK (EF: 63±3 to 62±2 %; FS: 18±2 to 21±2 %; CO: 75±11 to 56±4 mL/min), whereas in female Wistar rats there was a significant decrease in EF (78±3 to 66±5 %) and FS (36±3 to 26±4 %) with no change in CO (122±6 to 108±16 mL/min). Despite no evidence of major cardiac dysfunction at rest, a reduced Vmax was observed in GK rats compared to Wistar controls (18±1 vs. 24±2 m/min). These results suggest that despite no major apparent systolic dysfunction after myocardial I/R, female GK rats exhibit reduced exercise capability compared to Wistar rats, highlighting the importance of challenging the heart to unmask potential dysfunctions that may not be apparent at rest.

Support or Funding Information

(CAPES 88881.187256/2018‐01, NHLBI PO1HL51971, NIGMS P20GM104357 and NIGMS U54GM115428)

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Paeo‐tang attenuates disharmony between the heart and kidney in L‐NAME‐induced hypertension
Authors: Na Se Won , Hong Mi Hyeon , Kim Hye Yoom , Ahn You Mee , Yoon Jung Joo , Lee Yun Jung , Lee Ho Sub , Kang Dae Gill
Published: June 2021

Hypertension has been approved to cause disharmony between the heart and kidney such as cardiac hypertrophy and kidney dysfunction. In traditional oriental medicine Paeo‐tang (PET) has been shown to have effects on blood circulation improvement. However, the beneficial effect of PET on hypertension remains unknown. In this study, we investigated that PET attenuates blood pressure and suppresses cardiac hypertrophy in NG‐nitro‐L‐arginine methylester (L‐NAME) rat model. Hypertensive rat models were induced by the administration of L‐NAME (40 mg/kg/day) and then PET (50 or 100 mg/kg/day) or Olmetec was treated for 2 weeks. PET treatment significantly suppressed the systolic blood pressure and decreased intima‐media thickness in the thoracic aorta. PET restored the L‐NAME‐induced decrease in aortic relaxation response to acetylcholine and atrial natriuretic peptide (ANP). However, PET didn't restore the aortic relaxation response to sodium nitroprusside. PET markedly restored the phosphorylation of endothelial nitric oxide synthase in aortic tissue. Heart weight and ANP mRNA expression in heart tissue were decreased by PET in a dose‐dependent manner. PET ameliorated the functional decline in the kidney such as albumin, blood urea nitrogen, creatinine. These results demonstrated that PET possesses vascular protective effects against L‐NAME‐induced hypertension. In addition, PET regulates harmony between the heart and kidney via inhibition of cardiac hypertrophy and renal dysfunction.

Support or Funding Information

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Cardiovascular Effects Of Acute Optogenetic Modulation Of Oxytocin‐PVN Neurons
Authors: Mohammed Mazher , Tan Yalun , Harrison Caitlin Baumer , Scott Karen A , Sumners Colin , de Kloet Annette , Krause Eric G.
Published: June 2021

The actions of oxytocin (OT), a neuropeptide that is largely synthesized in the paraventricular (PVN) and supraoptic (SON) nuclei of the hypothalamus, has been implicated in a variety of homeostatic processes. Recent studies have demonstrated that chronic activation of OT neurons in the PVN prevents hypertension that is a consequence of intermittent hypoxia/hypercapnia. The present study combines genetically‐modified mice with in vivo optogenetics to determine the cardiovascular consequences of selective inhibition or excitation of OT neurons residing in the PVN. Male mice engineered to direct the expression of Cre recombinase to the OT gene had adenoassociated virus synthesizing an inhibitory opsin (Switch), an excitatory opsin (ChR2), or enhanced yellow fluorescent protein (eYFP) bilaterally injected into the PVN. Subsequently, mice were implanted with fiber optics targeting the PVN. One month later, mice were anesthetized with isoflurane and were implanted with a Millar catheter into their left common carotid artery for continuous recording of blood pressure and heart rate. Relative to the eYFP control group, OT‐Cre mice expressing Switch exhibited reduced blood pressure (−24±6 mmHg) and heart rate (−21±9 BPM) in response to optogenetic inhibition when compared with the eYFP group (4±2 mmHg and 5±4 bpm; n=3, p<0.05). In contrast, in the ChR2‐injected group, blue light stimulation (1 min; 30 Hz; 20ms pulse width) significantly increased blood pressure by 15±2 mmHg while decreasing heart rate by −27±10 bpm when compared to controls (0±1mmHg and 9±5 bpm; n=5, p<0.01. Neuroanatomical experiments revealed that neurons in the PVN that synthesize OT send dense axonal projections to the median eminence, the nucleus of the solitary tract, and the rostral ventral lateral medulla. Collectively, the results suggest that OT synthesizing neurons in the PVN mediate cardiovascular function possibly by affecting autonomic outflow and/or the activity of neuroendocrine axes.

Support or Funding Information

NIH Funding supported the present study

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
The Effects of Fat Mass and Lean Mass on Blood Pressure Determinants in Healthy Young Men and Women
Authors: Connolly Kathleen , Middlemiss Jessica , Wilkinson Ian , McEniery Carmel
Published: June 2021

Background

Obesity is commonly associated with high blood pressure (BP) and cardiovascular risk, but it is not clear whether BP elevation is primarily associated with increased fat mass or lean mass, which is also increased in obesity. Moreover, few studies have focused on the relationship between haemodynamic determinants of BP, such as stroke volume (SV), cardiac output (CO), and peripheral vascular resistance (PVR), and fat mass or lean mass in healthy men and women.

Objective

This study was undertaken to determine whether BP and its haemodynamic determinants were more strongly associated with fat mass or lean mass, and whether the associations differed between males and females.

Methods

203 healthy human volunteers (103 males, 100 females) aged <50 years were recruited. Body composition was analysed using a Tanita bio‐impedance scale. Clinic (seated) systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured after 5 minutes of rest. Stroke volume and CO were measured using an inert gas re‐breathing method. Peripheral vascular resistance (PVR) was calculated from mean arterial pressure and CO. Data were analysed using Spearman correlation.

Results

In men, fat mass was positively correlated with DBP (r = 0.51, p < 0.001) only, while lean mass was positively correlated with SBP, CO, and SV (rSBP = 0.33, pSBP < 0.01; rCO = 0.37, pCO < 0.001; rSV = 0.45, pSV < 0.001); lean mass was inversely correlated with PVR (r = −0.31, p < 0.01). In women, fat mass and lean mass were both positively correlated with SBP, DBP, CO and SV (fat mass: rSBP = 0.48, pSBP < 0.001; rDBP = 0.51, pDBP < 0.001; rCO = 0.40, pCO < 0.001; rSV = 0.29, pSV < 0.01) (lean mass: rSBP = 0.41, pSBP < 0.001; rDBP = 0.40, pDBP < 0.001; rCO = 0.52, pCO < 0.001; rSV = 0.47, pSV < 0.01), while lean mass was also inversely correlated with PVR (r = −0.34, p < 0.01).

Conclusions

The relationship between body composition and blood pressure determinants differs between young men and women. These differences should be kept in mind when investigating the physiological mechanisms underlying obesity‐associated hypertension in humans. The impact of lean mass on blood pressure elevation should not be overlooked, particularly in younger males.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Sibjotang attenuates Doxorubicin‐Induced Cardiac Hypertrophy: Involvement of necroptosis
Authors: Son Chan Ok , Yoon Jung Joo , Han Byung Hyuk , Kim Hye Yoom , Lee Yun Jung , Kang Dae Gill , Lee Ho Sub
Published: June 2021

Doxorubicin is one for the most widely used anti‐neoplastic agents, however severely limited due to its cumulative cardiotoxicity, which develops over time into congestive heart failure. Sibjotang (Shizaotang), traditional herbal medicine formula, has been reported regulates the body fluid blood pressure homeostasis. The present study was aimed at determining the effect and regulatory mechanism of Sibjotang in doxorubicin‐induced cardiotoxicity in H9c2 cells. Immunofluorescence staining analysis showed that Sibjotang decreased doxorubicin‐induced increase in H9c2 cardiomyocytes size in does dependent manner. Pre‐treatment with Sibjotang significantly inhibited doxorubicin‐induced cardiac hypertrophic markers such as ANP (atrial natriuretic peptide), BNP (brain natriuretic peptide) and β‐MHC (β‐myosin heavy chain) mRNA expression levels. Sibjotang reduced hypertrophy‐associated transcription factor GATA 4 (GATA binding factor 4) expression. Pre‐treatment with Sibjotang significantly inhibited doxorubicin‐induced necroptosis‐associated kinase such as receptor‐interacting serine/threonine‐protein kinase RIPK1 and RIPK3 without affecting cell viability. In conclusion, doxorubicin‐induced cardiac hypertrophy and necroptosis were attenuated by Sibjotang. Therefore, Sibjotang may be potential herbal therapies targeting cardiotoxicity resulting from anti‐cancer agents.

Support or Funding Information

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Beneficial Changes Promoted by L‐arginine and Aliskiren in Resistance Vessels in 2K1C hypertensive rats
Authors: Mengal Vinicius , Tiradentes Renata Viana , Santuzzi Cintia Helena , de Almeida Simone Alves , de Abreu Glaucia Rodrigues , Gouvea Sonia Alves
Published: June 2021

Renovascular hypertension is characterized by increased angiotensin II and oxidative stress and by endothelial dysfunction. By acting on multiple targets and promoting diverse actions, angiotensin II (Ang II) plays a pivotal role in vascular dysfunction. The purpose of this study was to test whether the administration of aliskiren (ALSK) and L‐arginine (L‐arg) would restore endothelial dysfunction and reduce inflammation and oxidative stress in a rat renovascular hypertension model. Hypertension was induced by clipping the right renal artery, and the following five groups were divided: SHAM operated; 2‐kidney, 1‐clip (2K1C); 2K1C plus ALSK; 2K1C plus L‐ARG; and 2K1C plus ALSK+ L‐ARG. The vascular reactivity to norepinephrine (NE; 10(−9) to 2 × 10(−3) mol/L) and acetylcholine (ACh; 10(−10) to 10(−3) mol/L) was evaluated in the mesenteric arteriolar bed through concentration‐effect curves. The structure was assessed by histology and biomolecular analyzes were done via western blot, lipid peroxidation, DHE and DAF. For 4 weeks, blood pressure (BP) was monitored and endothelium‐dependent vasoconstriction and relaxation were assessed in mesenteric arteriolar. ALSK+L‐arg reduced BP and the contractile response to norepinephrine and improved acetylcholine relaxation. Incubation with N‐nitro‐L‐arginine methyl ester (L‐NAME) and L‐NAME+ Indometacin increased the response to norepinephrine in the 2K1C group and the effect was greater and partially improved, respectively, with the treatments. However, It was improved acetylcholine relaxation with the both of the treatments. The bioavailability of nitric oxide increased with the treatments, and the inflammation and oxidative stress was reduced with the treatments. L‐arginine and aliskiren attenuates the morphofunctional deleterious effects of Ang II on resistance vessels. The benefits of L‐arginine and aliskiren seem to occur through restoring the balance of ROS/NO. Therefore, this study opened new avenues for further clinical targeting of the treatment of cardiovascular diseases related to activation of the renin‐angiotensin system. In conclusion, combined ALSK+L‐arg treatment normalizes BP and prevents endothelial dysfunction in 2K1C hypertensive rats.

Support or Funding Information

This research was supported by a CNPq research grants. This study was funded by Fundação de Amparo a Pesquisa do Espirito Santo (FAPES‐Brazil) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq‐Brazil).

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Exercise Hypertension and Aortic Stiffness in Adults Survivors of Prematurity
Authors: Peters Matthew E
Published: June 2021

Matthew Peters, Christopher R. Barnard, Emily T. Farrell, Mari Palta, Marlowe W. Eldridge, Harald M. Stauss, John F. Dagle, Jeffrey Segar, Gary L. Pierce, Melissa L. Bates

Rationale

The long‐term consequences of premature birth, and the interventions necessary to treat premature birth, are not well understood. Previous studies have shown pulmonary insufficiencies, but few have looked at hemodynamic variables. None have looked into exercise and hypoxia intolerance in these adults who were born prematurely.

Objectives

To determine exercise capacity and hemodynamic responses during exercise and hypoxia in prematurely born adults. To derive pulse wave velocity under normoxia and hypoxia

Methods

Preterm (N=10) and term‐born, aged matched subjects (N=12), were performed incremental exercise under normoxia (21% O2) or hypoxia (12% O2) until volitional maximum.

Results

Preterm subjects and term‐born subjects have similar forced expiratory volume in one second (FEV1), functional vital capacity (FVC), FEV1/FVC, diffusion capacity of carbon monoxide, maximum wattage, and VO2 max. The preterm adults had higher heart rates, systolic blood pressure, and pulse pressure throughout the exercise protocol under normoxia and hypoxia. They had a higher diastolic pressure and mean arterial pressure during exercise under normoxia, but had lower diastolic blood pressure and mean arterial pressure under hypoxia. Adults born prematurely also had higher pulse wave velocities in normoxia and hypoxia, but there was no effect of the gas condition.

Conclusions

This study demonstrated that heart rate and blood pressure responses to exercise in adults who survived prematurity differ from those who were born at full‐term. Premature adults elevated blood pressure more than term‐born adults when exercise under normoxia. A similar trend is seen under hypoxia, however, diastolic blood pressure falls which may be due to increased sensitivity to or production of vasodilators under hypoxic conditions.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
GPR37L1 Regulates the Expression and Function of NHE3 in Renal Proximal Tubule Cells
Authors: Zheng Xiaoxu , Asico Laureano D , Armando Ines , Jose Pedro A , Konkalmatt Prasad R
Published: June 2021

The orphan G protein‐coupled receptor 37L1 (GPR37L1) has strong homology with the endothelin‐B receptor but it does not interact with endothelin. GPR37L1 is known to be expressed in several regions in the brain, but its expression profile and function in peripheral tissues are poorly understood. We determined the expression profile of GPR37L1 in mouse organs by RT‐PCR and immunoblot analyses and further used immunohistochemical analyses to locate the sites of GPR37L1 expression within the tissues. Quantitative RT‐PCR revealed that the expression of GPR37L1 was highest in the brain, heart, stomach, testis, and ovary and less in the kidney, liver, lung, spleen, pancreas, and skeletal muscle. Immunohistochemical analyses revealed the expression of GPR37L1 in specific regions within some organs, e.g., neurons in the granular layer of the cerebellum, epithelial cells lining the airway of the lung, epithelial cells lining the gastric mucosa, apical membrane of renal proximal tubule cells (RPTCs), early spermatids in seminiferous tubule of the testis, and granulosa cells in the secondary follicle of the ovary. Transient expression of GPR37L1 in human (h)RPTCs increased sodium transport whereas silencing of GPR37L1 decreased sodium transport. Inhibition of sodium hydrogen exchanger type 3 (NHE3) expression abrogated the GPR37L1‐mediated increase in sodium transport. Renal‐restricted silencing of Gpr37l1 in mice increased urine output and sodium excretion and decreased systolic and diastolic blood pressures. The renal‐selective silencing of GPR37L1 decreased the expression of NHE3 but not the expression of Na+/K+‐ATPase or sodium/glucose cotransporter 2. Over‐expression of GPR37L1 in hRPTCs increased the phosphorylation of ERK1/2 (1.73 ± 0.11‐fold, P<0.05) and AKT (1.89 ± 0.12‐fold, P<0.01) and decreased forskolin‐induced cAMP production (38% ± 4.9). Our findings show that in the kidney GPR37L1 increases luminal RPT sodium transport and blood pressure by increasing NHE3 expression, via the ERK1/2 and AKT pathway and increasing NHE3 function by suppressing cAMP production via Gai. Taken together, these results show that GPR37L1 expressed in RPTCs plays an important role in increasing renal sodium transport; GPR37L1 may be a novel target to design drugs to treat hypertension.

Support or Funding Information

US National Institute of Health R56DK116828, R37HL023081, P01HL074940, R01HL092196, R01DK039308, and R01DK090918, and National Kidney Foundation NKF‐MD‐Mini.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Arterial smooth muscle cell PKD2 (TRPP1) channels contribute to angiotensin‐induced vascular remodeling
Authors: Daker Hailey , Reinert Angela , Fernandez‐Pena Carlos , Jaggar Jonathan H , Bulley Simon
Published: June 2021

Hypertension is associated with structural changes of resistance‐sized arteries, a process referred to as vascular remodeling, resulting in an increase in total peripheral resistance. One stimulus that exerts changes in arterial structure is an elevation in the vasoconstrictor angiotensin II (ang II), which mediates vascular smooth muscle cell growth, consequently resulting in vascular remodeling. Arterial smooth muscle cell PKD2 (TRPP1) channels, a member of the transient receptor potential (TRP) channel superfamily of ion channels, are upregulated in resistance‐sized arteries in ang II‐treated mice when compared to saline‐perfused controls. In addition, ang II‐treated conditional smooth muscle‐specific PKD2 knockout (PKD2sm−/−) mice demonstrate attenuated arterial wall remodeling and reduced blood pressure. An alteration in the expression and function of vascular smooth muscle cell ion channels also contributes to vascular remodeling through the promotion of cell proliferation. Here, we demonstrate that transient receptor potential canonical type 3 (TRPC3) and epidermal growth factor receptor (EGFR) channels, both indicated previously to contribute to ang II‐mediated vascular remodeling, are upregulated in mesenteric arteries isolated from ang II‐treated mice. During hypertension, TRPC3 channel function is also elevated, as demonstrated by application of the TRPC3 channel blocker pyrazole 3 (Pyr3) to pressurized 3rd and 4th order mesenteric arteries. Ang II‐treated PKD2sm−/− mice show reduced TRPC3 and EGFR expression, as well as decreased TRPC3 function when compared to ang II‐treated PKD2fl/fl controls. These data suggest that arterial smooth muscle cell PKD2 channels may contribute to TRPC3‐induced vascular remodeling in resistance‐sized mesenteric arteries.

Support or Funding Information

AHA 16SDG27460007

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Blood Flow Restriction Exercise Increases the ACE2/ACE Ratio and ACE2 Shedding in CD34+ Cells in Healthy Individuals
Authors: Joshi Shrinidh , Mahoney Sean , Pitts Logan , McCullough Shane , Hackney Kyle , Jarajapu Yagna PR
Published: June 2021

Adult CD34+ hematopoietic stem/progenitor cells in the systemic circulation are bone marrow‐derived and have the propensity of maintaining cardiovascular health. We have previously shown that activation of the vascular protective axis of renin angiotensin system (RAS), Angiotensin Converting enzyme‐2 (ACE2)/Angiotensin‐(1–7)/Mas receptor axis stimulates vasoreparative functions of CD34+ cells in health and disease. Importantly, in vitro exposure of CD34+ cells to hypoxia enhanced the expressions of ACE2 and Mas, and stimulated ACE2 shedding, but ACE and AT1 receptors, members of the vascular detrimental axis of RAS were not affected. This study tested if acute regional hypoxia recapitulates the in vitro observations in healthy individuals. Blood flow restriction exercise (BFR) was performed in the lower body by applying 80% limb occlusion pressure (LOP). Delphi personalized tourniquet system was used to accomplish the target LOP. Exercise protocol consisted of total four sets (30/15/15/15 repetitions) of movements at 10% of maximal strength. Muscle oxygen saturation was determined by using MOXY muscle oxygen monitor. Peripheral blood was collected two weeks before (control) and 30 min after BFR. CD34+ cells were enumerated by flow cytometry, and ACE and ACE2 activities in plasma, and in cell lysates and cell‐free supernatants were determined. Plasma concentrations of SDF and VEGF were analyzed by ELISA. BFR prescribed at 80% LOP resulted in muscle oxygen levels of 14.1% compared to 50.9% in the resting condition. As predicted, circulating CD34+ cells were increased following BFR (before 356±59.1 and after 835±62.1/mL blood, P<0.001, n=5), which was associated with increased plasma levels of SDF and VEGF (4‐ and 3‐fold, respectively, compared to control (P<0.001, n=5)). ACE2 activity was increased in the whole cell lysates of Lineage‐negative cells resulting in the ACE2/ACE ratio of 11.7±0.5 compared to the baseline ratio of 9.1±0.9 (P<0.05, n=5). Cell supernatants have 3‐fold increase in ACE2/ACE ratio following BFR compared to the baseline levels (P<0.001, n=5). Collectively, these findings provide compelling evidence for the upregulation of ACE2, the vasoprotective enzyme of RAS, by acute regional hypoxia in HSPCs. BFR‐exercise regimen could be a promising approach for enhancing or restoring cardiovascular health in individuals that are poor mobilizers or those at risk for the development of cardiovascular complications.

Support or Funding Information

National Institute of General Medical Sciences (NIGMS) and National Institute of Aging (NIA) AG056881.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Novel Pilot Study Reveals that Heat Therapy Increases Muscle Mitochondrial Quality Control and Respiratory Efficiency in Healthy Human Subjects
Authors: Von Schulze Alex , Fuller Kelly NZ , McCoin Colin , Fernandez Clara Amat , Thyfault John , Geiger Paige
Published: June 2021

Immense focus has been placed on novel treatment strategies to prevent or reverse insulin resistance and type 2 diabetes (T2D). We have shown that heat therapy (HT) in rodents protects against high‐fat diet induced skeletal muscle insulin resistance and impaired glucose homeostasis. However, it remains unknown whether this effect can be translated to humans. The purpose of this pilot study was to determine if HT via hot water immersion was well tolerated in humans and altered mitochondrial metabolism in skeletal muscle. Healthy male and female participants (n=5/sex) underwent one bout of HT increasing core temperature to 38.5°C for 1h. Muscle biopsies were taken one week prior and 24h post HT to determine whether HT impacted mitochondrial respiratory capacity and mitochondrial quality control via autophagy. HT was well tolerated in all subjects and resulted in acute increases in heart rate and reductions in systolic and diastolic blood pressure. HT did not significantly alter maximal mitochondrial respiratory capacity at basal, state3, state3S, or uncoupled states with either palmitoyl‐carnitine + palmitoyl‐CoA (palmitate) or pyruvate + glutamate + malate (PGM) as substrates. However, HT tended to improve respiratory efficiency as indicated by a reduced coupling control ratio (basal/state3) for PGM. Of interest, this improved efficiency and maintenance of mitochondrial respiratory capacity occurred despite HT‐induced reductions in mitochondrial content as inferred by citrate synthase activity. We believe this reduction in muscle mitochondrial content occured as a result of mitophagy ‐ the targeted degradation of damaged mitochondria. Our hypothesis is supported by the observed reductions (or degradation) of the autophagy/mitophagy related protein, microtubule‐associated Proteins 1A/1B light chain 3B‐ phosphatidylethanolamine (LC3II). For the first time, our data suggest that HT increases mitochondrial quality control (via enhanced autophagy/mitophagy) and enhances respiratory efficiency in human skeletal muscle. These data provide promising results for further analysis in metabolically impaired obese subjects.

Support or Funding Information

NIH P30GM122731; Madison and Lila Self Graduate Fellowship (The University of Kansas)

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