bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evidence for altered DNA methylation as a major regulator of gene expression in calcific aortic valve disease (671.15)
Authors: Nwachukwu Nneka , Hagler Michael , Kafa Rami , Roos Carolyn , Miller Jordan 
Published: June 2021

Aging is a major risk factor for calcific aortic valve disease (CAVD). While recent work suggests that DNA methylation patterns are dramatically altered with aging, changes in DNA methylation patterns in age‐related cardiovascular diseases remain largely uncharacterized. Thus, we tested the working hypothesis that de novo DNA methyltransferase levels (DNMT3b in particular) are significantly increased in stenotic human aortic valves and would serve to repress expression of protective genes. We used human aortic valves that were either normal (NORM) or stenotic (STEN). qRT‐PCR and Western blotting were used to examine analyze changes in DNMT3b levels and markers of osteogenesis. DNA methylation was examined using ELISA‐based methods for total methylation and Illumina 450k Beadchip assays for site‐specific methylation between NORM and STEN valves. The pro‐osteogenic marker expression, Sp7, was increased by 4±1 fold in STEN valves compared to NORM tissue. While mRNA levels of DNMT3b only tended to be increased in STEN valves, protein levels of DNMT3b were dramatically increased in STEN valves compared to NORM valves (13.9±3‐fold increase). Increases in DNMT3b levels were associated with an increase in global DNA methylation, and 450k beadchip analysis identified more than 6,000 differentially‐methylated sites between NORM and STEN tissue. Collectively, these data identify DNA methylation as a potentially novel and major regulator of gene expression in end‐stage calcific aortic valve stenosis.NHLBIGrant Funding Source: NHLBI
Effects of stenosis on hemodynamics in carotid artery bifurcation using 2D MR‐imaging computational fluid dynamics: simulated versus real cases (671.4)
Authors: Chatpun Surapong , Prakobkarn Arpapan , Ina Natee , Saeheng Sakchai 
Published: June 2021

Carotid artery stenosis is one of major risks of stroke. Magnetic resonance (MR) imaging combined with computational fluid dynamics becomes a powerful tool to investigate hemodynamic changes in circulatory system for specific patients. In this study, hemodynamics obtained from a real stenotic model of carotid artery from two patients was compared with a simulated stenotic model from two healthy subjects. MR angiographic image of carotid artery was reconstructed as an input geometry for two‐dimensional computational fluid dynamics. Inlet velocity used in the calculation was obtained from Doppler ultrasound measurement. This calculation was based on the simple assumptions i.e. incompressible and Newtonian fluid, rigid vascular wall and non‐slip condition at wall. The computational results showed that stenosis in common carotid artery increased blood flow velocity in internal carotid artery which was higher than that in external carotid artery. Increased severity of stenosis also enhanced blood flow velocity but lowered wall shear stress on the inner wall of internal carotid artery. Multiple stenotic points decreased velocity of internal carotid artery compared with single point stenosis. This study demonstrated that the simulated stenotic model of carotid artery from healthy subjects has conditionally used to represent the effects of stenosis found in the real stenotic model.Grant Funding Source: Supported by Facualty of Medicine, Prince of Songkla University and NSTDA
Loss of cerebral blood flow autoregulation and assessment of the critical cerebral perfusion pressure at high ICP (674.14)
Authors: Nemoto Edwin , Bragin Denis , Statom Gloria , Bragina Olga 
Published: June 2021

Objective: To study the effect of increased intracranial pressure (ICP) on the critical cerebral perfusion pressure (CPP) and its relationship to the loss of cerebral blood flow (CBF) autoregulation.Background: Earlier studies showed that the critical cerebral perfusion pressure (CPP) fell from 60 to 30 mmHg as determined by decreasing arterial pressure as opposed to increasing intracranial pressure (ICP), respectively. We hypothesized that the decrease in the critical CPP at high ICP was due to microvascular shunting resulting in a pathological higher CBF at a lower CPP.Methods: Using two‐photon laser scanning microscopy (2PLSM) we measured microvascular (3‐25 m diam) flow velocity in rat cerebral cortex by increasing ICP or decreasing arterial blood pressure. In separate studies we also increased ICP progressively while monitoring the capillary (CAP) to microvascular shunt (MVS) ratio to study the effect of increasing ICP on the development of microvascular shunts.Results: The reduction in critical CPP with increasing ICP was due to increased microvascular shunting resulting in a sustained CBF at a lower critical CPP, which therefore decreased the critical CPP from 60 to 30 mmHg and associated with increased microvascular shunting. A progressive increase in ICP resulted in a parallel increase in the ratio of MVS/CAP ratio.Conclusion: The decrease in critical CPP obtained when ICP is increased as opposed to decreasing arterial pressure is due to the opening of microvascular shunts thereby creating low resistance microvascular conduits through the brain. The progressive increase in MVS with increasing ICP leads to the loss of CBF autoregulation, which differs from that observed at high CO2.Grant Funding Source: NIH RO3 NS051639;AHA 2BGIA11730011
Ultrasound‐mediated nanoparticle delivery across the blood‐brain barrier (676.17)
Authors: Timbie Kelsie , Nance Elizabeth , Zhang Clark , Miller Wilson , Song Ji , Hanes Justin , Price Richard 
Published: June 2021

Introduction: The intact blood‐brain barrier (BBB) presents a major obstacle for drug delivery to the brain, as it prevents the vast majority of therapeutics from entering brain tissue. Noninvasive focused ultrasound (FUS) in conjunction with microbubbles (MB) has been shown to cause safe, reversible, localized disruption of the BBB. This work examines the ability of MR guided FUS to deliver specialized brain‐penetrating nanoparticles (NP) across the BBB. NPs were 60 nm in diameter and covered with a dense PEG coating to permit diffusion through brain tissue.Materials and Methods: Anesthetized rats were coupled to the 1.14 MHz FUS system and given an IV co‐injection of fluorescent NPs and MBs immediately before sonication. Peak negative pressure was either 0.4 MPa or 0.6 MPa. Immediately following sonication, T1‐weighted contrast enhanced MRI images were captured to verify BBB disruption. Animals were placed on a heating pad at 37°C for one hour to allow increased NP uptake. Mounted brain sections were stained with BS‐I lectin to reveal endothelial cells (ECs) and imaged with confocal microscopy.Results and Discussion: Treatment with 0.6 MPa tripled NP coverage within the brain and produced larger NP “clouds” extending into the brain parenchyma, in addition to significantly increasing the occurrence of large NP clouds (>100 μm2) Furthermore, treatment with higher US pressure increased NP delivery to brain parenchyma rather than to the endothelial cells (ECs) lining the vasculature. Control regions showed no NP delivery.Conclusions: Our results indicate that varying US pressure can divert NP delivery between the endothelium and brain parenchyma.Grant Funding Source: Supported by NIH R01 CA164789 and The Focused Ultrasound Surgery Foundation
Breast cancer cell homing to bone in vivo is modulated by zoledronic acid (676.6)
Authors: Reeves Kimberley , Albon Jacob , Eaton Colby , Brown Nicola 
Published: June 2021

Cancer metastasis to the skeleton causes mortality in breast cancer, however the mechanisms involved in bone metastases development remain unclear. A metastatic initiating cell (MIC) phenotype CD44+/CD24‐/ALDHhigh has been identified in breast cancer. Zoledronic acid (zol), a bone anti‐resorptive bisphosphonate is currently the only agent with proven benefit in breast cancer. This study investigates whether zol modulates MIC homing in the early stages of breast cancer bone metastasis using the Dorsal Skinfold Chamber (DSC) metatarsal model in vivo.Following DSC metatarsal implantation, mice were treated weekly either before or after intra‐cardiac MDA‐MB‐231 tumour cell injection (1x105) for 4 weeks (Zol: 25µg/kg/injection=100μg/kg or PBS control). MDA‐MB‐231 cells were sorted into ALDHhigh and ALDHlow subpopulations using the ALDEFLUORkit and then injected into groups of mice (n=6), treated with zol before tumour cell injection. Chamber tissue and metatarsal recordings were made every 48hr for up to 4 weeks to identify tumour cell homing. At the end of the study, tissue was harvested and processed for µCT, multi‐photon analysis, histology and immunohistochemistry.Zol treatment reduces MDA‐MB‐231 cells homing to bone by 76% (before) and 62% (after) compared to control animals. ALDHhigh cells home to bone in significantly (p<0.05) higher numbers than ALDHlow cells (Day 25: 10.7±1.3 cells vs. 1.1±0.6 cells). Week zol administration (before tumour cell injection) does not reduce MDA‐MB‐231 cells bone‐homing.Weekly treatment with zol reduces breast tumour cell homing to bone, whereas ALDHhigh cell homing appears resistant to zol treatment in this model.
SGLT inhibitors attenuate NO‐dependent vascular relaxation in mouse pulmonary artery (677.3)
Authors: Han Ying , Cho Young‐Eun , Ayon Ramon , Dai Anzhi , Yuan Jason X.‐J. , Makino Ayako 
Published: June 2021

Sodium‐glucose cotransporter 2 (SGLT2) inhibitors are a new class of oral drugs for the treatment of type 2 diabetes and they reduce plasma blood glucose levels by inhibiting renal glucose reabsorption. However, there are no data focusing on microvascular or cardiovascular outcomes. The present study is designed to determine whether SGLT inhibitors, phlorizin (nonspecific SGLT1/SGLT2 inhibitor) and canagliflozin (SGLT2 specific inhibitor), regulate vascular relaxation in mouse coronary and pulmonary arteries. Isometric tension experiments were performed to evaluate vascular function. Phlorizin significantly decreased sodium nitroprusside (SNP, NO donor)‐dependent vascular relaxation in pulmonary arteries; however phlorizin did not alter SNP‐dependent relaxation in coronary arteries. Contrary to our expectation, phlorizin had no effect on either 8‐Bromo‐cGMP (a cell‐permeable cGMP analogue) or papaverine (phosphodiesterase inhibitor)‐induced relaxation in mouse pulmonary arteries. Canagliflozin inhibited SNP‐dependent vascular relaxation in a dose dependent manner. RT‐PCR data showed that SGLT2 mRNA expressed in small intestine, HEK293, pulmonary endothelial cells and pulmonary smooth muscle cells, while SGLT1 mRNA expressed only in small intestine. These results indicate that SGLT2 regulates NO‐dependent relaxation in mouse pulmonary arteries. Grant Funding Source: Supported by the NIH/NHLBI grant HL115578
Divergence in depressive symptom severity and vascular dysfunction with gender in rats with unpredictable chronic mild stress (680.20)
Authors: Stanley Shyla , Brooks Steven , Butcher Joshua , D'Audiffret Alexandre , Skaff Paulina , Chantler Paul , Frisbee Jefferson 
Published: June 2021

Chronic stress leads to many negative health outcomes proportional to the severity of developed depressive symptoms. This includes vascular reactivity, as endothelial function is compromised by 8 weeks of unpredictable chronic mild stress (UCMS). To extend this, we imposed 8 weeks of UCMS on healthy rats of both genders from 9 weeks of age. In males, plasma cortisol and depressive symptom severity (coat status, anhedonia, delayed grooming) were elevated. Endothelial‐dependent dilation to methacholine/acetylcholine was impaired in conduit arteries/skeletal muscle arterioles, indicating a near complete loss of NO bioavailability and increased production of TxA2 with elevated ROS. Endothelium‐independent dilation was intact. However, in females, depressive symptoms and plasma cortisol increases were more severe, although impairments to vascular reactivity were attenuated. The effects of elevated ROS and constrictor prostanoids were also blunted. These results suggest that, in comparison to males, female rats are more susceptible to chronic stress in terms of the severity of depressive behaviors, but that the subsequent development of vasculopathy is blunted.Grant Funding Source: Supported by National Institutes of Health and American Heart Association
Evaluation of the cardiovascular changes in juvenile and adult female rats submitted to chronic intermittent hypoxia (680.3)
Authors: Souza George , Bonagamba Leni , Amorim Mateus , MORAES DAVI , Machado Benedito 
Published: June 2021

Chronic intermittent hypoxia (CIH) induces hypertension in juvenile and adult male rats due to an increase in sympathetic activity. There is experimental evidence that changes in respiratory network are driving the sympathetic overactivity in this model. Female rats are more resistant to the development of hypertension in several experimental models. In this study, we evaluated the cardiovascular changes in juvenile and adult female rats in response to CIH. Juvenile female rats were exposed to CIH for a 10 days protocol and adult female rats to a 35 days protocol and at the end of the protocols direct measurements of arterial pressure were performed in control and CIH rats. Juvenile female rats exposed to CIH (n=30) presented significant increase in arterial pressure compared to their respective control [n=34 (94±1 vs 86±1 mmHg, p<0.05)], as well adult female rats exposed to CIH (n=27) when compared to their respective control [n=26 (111±1 vs 104±1 mmHg, p<0.05)]. We concluded that juvenile and adult female rats submitted to CIH develop high arterial pressure similarly to male rats after CIH, suggesting that sexual characteristics and hormones are not playing a protective role in this experimental model of hypertension.Grant Funding Source: Supported by CAPES, CNPQ and FAPESP
Effects of gender on mitochondria‐derived middle cerebral artery function in rats (680.7)
Authors: Rutkai Ibolya , Dutta Somhrita , Walter Korey , Katakam Prasad , Busija David 
Published: June 2021

Significant gender differences in the composition and functionality of cerebral arteries have been shown, but effects of mitochondrial‐derived responses have not been examined. Our study tested whether mitochondrial mechanisms promoting changes in cerebral vascular tone are different in male and female rats. We examined the effects of a mitoKATP opener, diazoxide (DZ), bradykinin (BK), and sodium nitroprusside (SNP) on isolated, pressurized MCAs from 9 week old male and female Sprague‐Dawley rats. We measured levels of mitochondrial proteins of the voltage dependent anion channel (VDAC), Complex V, the fission protein DRP‐1, and endothelial and neuronal nitric oxide synthase (NOS). Levels of Complex V and VDAC were similar in male and female rats, but the protein expression of phosphorylated DRP‐1, total and phosphorylated eNOS and nNOS in MCAs were significantly higher in females than in males. However, DZ induced vasodilation was greater in male MCAs (21.1±4.5 μm to 50μM, 44.8±4.7 μm to 100 μM) compared with female MCAs (13.3±2 μm to 50 μM, 35±3.2 μm to 100 μM) whereas vasodilator responses to BK and SNP were similar for both sexes. Treatment with L‐NAME and the denudation of endothelium abolished the DZ induced vasodilation to all of the DZ concentrations in female MCAs. Our data suggest that mechanisms underlying gender differences in mitochondrial derived vasoreactivity are associated with NO production.Grant Funding Source: NIH grants HL‐077731, HL‐030260, HL‐065380, and HL‐093554.
Evaluation of the respiratory and cardiovascular activities in juvenile rats submitted to sino‐aortic denervation (681.9)
Authors: Amorim Mateus , Bonagamba Leni , Souza George , Moraes Davi , Machado Benedito 
Published: June 2021

Rats submitted to sino‐aortic denervation (SAD) present normal basal sympathetic activity and mean arterial pressure (MAP) few days after the surgical procedure. In the present study, we evaluated the cardiovascular and respiratory changes 3 and 10 days after SAD. Male juvenile Wistar rats were submitted to SAD or sham surgery and four groups were evaluated 3 (SAD and Sham) and 10 days (SAD and Sham) after the surgery. Cardiovascular and respiratory parameters were recorded in awake rats and the arterial baroreflex was tested to verify the efficacy of SAD. It was observed that MAP in all experimental groups was similar. The variability of MAP was significantly higher in SAD than in Sham rats at 3 (4.63±0.27 vs 2.86±0.16 mmHg) and 10 days (5.68±0.56 vs 2.68±0.18 mmHg). No major changes in the respiratory parameters were observed in SAD at 3 days after the surgery, but the respiratory frequency (114±4 vs 136±5 cpm) and minute volume (1457±67 vs 1998±165 mL/Kg/min) were significantly reduced 10 days after SAD. The durations of expiration (0,34±0,01 vs 0,27±0,01 sec), inspiration (0,22±0,01 vs 0,19±0,01 sec) and respiratory cycle (0,56±0,02 vs 0,46±0,02 sec) were significantly increased 10 days after SAD. These data suggest that 10 days after SAD changes in the respiratory pattern may contribute to the modulation of the sympathetic activity and prevent major changes in MAP in SAD rats.Grant Funding Source: Supported by FAPESP, CAPES and CNPq
Perivascular inflammation drives sympathetic hyperinnervation and hypertension in obesity (682.1)
Authors: Haddock Rebecca , Matthaei Klaus , Drummond Grant , Hill Caryl 
Published: June 2021

Hypertension in obesity occurs as a result of abnormal increases in sympathetic nerve density over arteries controlling blood pressure; the causative factors underlying these changes are unknown. Here we examine the role of inflammatory cell infiltration to changes in perivascular nerve innervation over small mesenteric and renal arteries from C57BL/6 and Rag1‐/‐ mice fed a normal or high fat diet. Pressure myography, electrophysiology and videomicroscopy was used to measure intraluminal pressure, membrane potential, vessel diameter. Nerves were activated by electrical field stimulation. Immunohistochemistry was performed using antibodies against nerve growth factor (NGF), CD3+ (T cells) and F4/80 (macrophages). Sympathetic innervation was examined using anti‐synaptophysin (synaptic vesicles). Images were collected using confocal microscopy and analysed using Image J. Obese C57BL/6 mice were hypertensive. Nerve‐mediated contractions and excitatory junction potentials (EJP) were augmented (P<0.05) and the perivascular sympathetic nerve plexus was denser (P<0.05). Numbers of perivascular NGF‐producing immune cells (T cells and macrophages) were increased (P<0.05). Infiltration of these cells was shown to precede expansion of the nerve plexus (P<0.05). Rag1‐/‐ mice fed a HFD also became obese. However, numbers of perivascular NGF‐producing immune cells were not increased, arteries were not hyperinnervated and mice remained normotensive. Neurogenic hypertension in obesity occurs as a consequence of the infiltration of NGF positive immune cells to the vascular adventitia and expansion of the perivascular sympathetic nerve plexus.Grant Funding Source: Supported by the NHMRC to REH (466009)
Evidence for blood‐brain barrier Na‐K‐Cl cotransport, Na/H exchange and Na‐HCO3 cotransport involvement in hyperglycemia exacerbation of cerebral edema formation in ischemic stroke (685.3)
Authors: Chechneva Olga , Yuen Natalie , Tsai Yi‐Chen , Chen Yi‐Je , Anderson Steven , O'Donnell Martha 
Published: June 2021

Hyperglycemia (HG) exacerbates cerebral edema formation in ischemic stroke and worsens clinical outcome through poorly understood mechanisms. Our previous studies provided evidence that the blood‐brain barrier (BBB) Na transporters Na‐K‐Cl cotransport (NKCC), Na/H exchange (NHE) and Na‐HCO3 cotransport (NBC) are stimulated by ischemic factors, causing increased secretion of Na and water into the brain and consequent cerebral edema formation. In the present study we examined the effects of HG on cerebral microvascular endothelial cell (CMEC) NKCC, NHE and NBC expression and activity, as well the effects of ischemic factors on the Na transporter activities following HG exposures using methods that included Western blot, qRT‐PCR, radioisotopic flux assays and microspectrofluorometry. We found that HG (30 vs 5 mM glucose; 6, 24, 48 hr and 7 d) increased abundance of bovine and human CMEC NKCC1, NHE1 and NBCn1. These exposures to HG also significantly increased CMEC NKCC, NHE and NBC activities. mRNA levels of NHE1 but not NKCC1 or NBCn1 were significantly increased by 6 and 24 hr of HG. Osmotic controls (with mannitol or NaCl) had no effect on abundance, activity or mRNA levels. HG also caused a greater increase in ischemic factor stimulation of these Na transporter activities. Finally, MRI studies showed that bumetanide and HOE‐642 inhibition of NKCC and NHE reduced HG‐worsened edema in rats with cerebral ischemia.Grant Funding Source: Supported by NIH and ADA
Carbon monoxide excitatory effect in vasopressin neurons of heart failure rats involves nitric oxide/GABA signaling (686.24)
Authors: Reis Wagner , Biancardi Vinicia , Zhou Yiqiang , Stern Javier 
Published: June 2021

We showed that the gas neurotransmitter carbon monoxide (CO) regulates vasopressin (VP) neuronal activity. Neurohumoral activation in the hypothalamic paraventricular nucleus (PVN), characterized by elevated VP secretion, occurs during congestive heart failure (HF). Moreover, blunted nitric oxide (NO)/GABA inhibitory signaling pathways within PVN are major contributing factors. In this study we determined whether PVN expression of heme‐oxygenase‐1 (HO‐1), a CO‐synthesizing enzyme, was changed in HF; whether CO effects on the firing rate (FR) of VP neurons was altered, and whether CO effects were mediated by NO/GABA function. Immunofluorescence and western blots studies showed an increased PVN HO‐1 protein levels during HF (P<0.05). Additionally, patch‐clamp recordings obtained from identified VP neurons in transgenic eGFP‐VP rats, showed that tin‐protoporphyrin IX (20µM, a HO inhibitor) diminished FR in 75% VP responsive cells in HF rats, compared with no effects in 62% VP cells in sham rats. Besides, tricarbonyldichlororuthenium dimer (30µM, a CO donor) increased FR in 71% and 75% VP responsive neurons in HF and sham rats, respectively. Interesting, the majority of VP neurons in HF rats were non responsive to the CO donor after previous application of a NO blocker (62%) or a GABA blocker (80%). In addition, the excitatory CO effect was accompanied by a reduction of GABA currents in 93% of VP neurons in HF rats. Taken together, our results showed overexpression of PVN HO‐1 and excitatory CO responses on VP neurons in HF rats, likely involving changes in NO/GABA‐mediated signaling.Grant Funding Source: AHA 12POST12060540