bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 535: Impaired Natriuresis and Increased Salt Sensitivity in Response to Acute Salt Load During Western Diet-intake: Role of Trpv1
Authors: Wang Donna H , Zhong Beihua
Published: July 2021

Western diet (WD) intake increases morbidity of obesity, diabetes, and salt sensitive hypertension albeit mechanisms are largely unknown. We tested the hypothesis that the transient receptor potential vanilloid type 1 (TRPV1) channels are activated during WD intake to protect against salt-induced increases in blood pressure possibly via enhancing natriuresis. Wild-type (WT, C57BL/6) or gene-targeted TRPV1-null mutant (TRPV1
-/-
) mice were fed a normal (CON) or Western (WD) diet for 16-18 weeks. Mean arterial pressure (MAP), determined by radiotelemetry after acute sodium loading (NS, 0.9% NaCl) or vehicle (C) by gavage with or without treatment with Nω-nitro-l-arginine methyl ester (
L
-
NAME, 10mg/kg, ip.
) or a
TRPV1
agonist, N-oleoyldopamine (
OLDA, 0.1mg/kg, ip
), was not different between two strains fed a CON diet. WT or TRPV1-/- mice fed a WD diet had increased MAP after NS, with a greater magnitude in TRPV1-/- mice (p<0.05). OLDA decreased while L-NAME increased MAP in WT-WD-NS but not TRPV1-/-WD-NS mice (p<0.05). The urinary nitrates plus nitrites excretion (UNOx, umol*4h urine/kg BW), an indicator of renal nitric oxide (NO) production, was increased in both strains fed a CON diet after NS (p<0.05). OLDA further increased while L-NAME prevented NS-induced increases in UNOx in WT-CON-NS only or in both strains, respectively. TRPV1 ablation with WD intake decreased UNOx levels before NS and abolished NS-induced increment in UNOx (WT-WD-C: 0.3 ±0.06 vs. TRPV1-/-WD-C: 0.2 ±0.05; and WT-WD-NS: 0.7 ±0.1 vs. TRPV1-/-WD-NS: 0.3 ±0.1; p<0.05). OLDA further increased while L-NAME prevented NS-induced increment in UNOx in WT-WD-NS mice only (p<0.05). Urinary sodium excretion was increased in both strains fed a CON diet after NS (p<0.05), which was unaffected by OLDA or L-NAME. UNa was increased in WT-WD-NS but not TRPV1-/-WD-NS after NS. OLDA further increased while L-NAME prevented NS-induced increases in UNa in WT-WD-NS only. Thus, TRPV1 ablation increases salt sensitivity during WD intake possibly via impaired NS-induced renal NO production and sodium excretion. Activation of TRPV1 with OLDA enhances renal NO production and sodium excretion, resulting in prevention of increased salt sensitivity during WD intake.
Abstract 549: Angiotensin II Attenuates Apelin-36 Release from Human Placental Chorionic Villi
Authors: Yamaleyeva Liliya M , Brosnihan K. Bridget , Anton Lauren , McGee Carolynne , Mertz Heather L , Merrill David C
Published: July 2021

Angiotensin II (Ang II) and apelin have opposing actions in the regulation of blood pressure, vascular tone and angiogenesis, factors known to be important in pregnancy. Chorionic villi (CV) are essential for the transport of oxygen and metabolites in the maternal-fetal interface. Previous studies from our group demonstrated the upregulation of Ang II in the CV of preeclamptic women. Since the interaction between Ang II and apelin have been suggested in the cardiovascular system, we determined whether Ang II alters the release of apelin from the placental CV obtained from normotensive pregnant (NP) and preeclamptic (PRE) women. We also established whether Ang-(1-7) influences apelin release from the same set of tissue samples. CV were dissected from the placental tissue, washed and incubated for 0, 2 and 16 hours in DMEM/F12 media with or without Ang II (1 nM and 1 μM) or Ang-(1-7) (1 nM and 1 μM) under controlled O2 and CO2 tensions. The unstimulated release of apelin measured by a competitive radioimmunoassay was significantly reduced in the conditioned media from PRE compared to NP chorionic villi at 2 hrs (PRE: 181.1 ± 31 vs. NP: 309.5 ± 51.4 pg/ml, p<0.05). There was a significant increase in apelin release from both NP (267.8 ± 34.8 vs. baseline: 118.4 ± 27.3 pg/ml, p<0.01) and PRE (293.5 ± 25.8 vs. baseline: 122.6 ± 24.8 pg/ml, p<0.01) CV at 16 hours. Ang II or Ang-(1-7) inhibited the release of apelin from CV of the NP (p<0.05) but not of PRE at 2 hours. At 16 hours, however, Ang II or Ang-(1-7) inhibited the release of apelin from both NP and PRE villi (p<0.05). Immunostaining revealed the predominant localization of apelin receptor to syncytiotrophoblasts and fetal vascular cells of CV - areas associated with AT1 receptor localization. Our data showing a negative influence of Ang II on apelin release from chorionic villi suggest an opposing interaction between these peptides in the human placental tissue. Reduced apelin activity would remove its counter-regulatory actions on Ang II-induced endothelial dysfunction, increased vascular resistance, and inflammation - abnormalities which precede and sustain preeclampsia. A surprising inhibitory effect of Ang-(1-7) on apelin suggests a complex regulation of apelin within the RAS.
Abstract 558: Role of Angiotensin Converting Enzyme 2/angiotensin (1-7)/mas Axis in the Hypotensive Effect of Azilsartan
Authors: Iwanami Jun , Mogi Masaki , Tsukuda Kana , Wang Xiao-Li , Ohshima Kousei , Chisaka Toshiyuki , Bai Huiyu , Min Li-Juan , Horiuchi Masatsugu
Published: July 2021

Objective:
The possible counteracting effect of angiotensin (Ang)-converting enzyme (ACE)2/Ang (1-7)/Mas axis against the ACE/Ang II/ Ang II type 1 (AT
1
) receptor axis in blood pressure control has been highlighted. We examined the possibility that this axis might be involved in the anti-hypertensive effect of newly developed Ang II type 1 (AT
1
) receptor blocker (ARB), azilsartan, in comparison with olmesartan.

Methods:
Human renin (hRN) and human angiotensinogen (hANG) double transgenic mice (hRN/hANG-Tg) were used. Ten-week-old male hRN/hANG-Tg mice were administrated control chow or three different doses (1, 5 and 10mg/kg/day) of ARBs, azilsartan or olmesartan in chow for 4 weeks. Blood pressure was analyzed by radio telemetry method before drug administration and every two weeks after medication. Four weeks after drug administration, expression of ACE2 mRNA level was assessed by real time RT-PCR method.

Results:
Blood pressure was significantly higher in hRN/hANG-Tg mice compared with that in wild type (WT) mice. Treatment with all doses of azilsartan decreased blood pressure to the level of WT mice. Treatment with olmesartan (1 mg/kg/day) decreased blood pressure; however, this decrease was weaker than that with azilsartan at the same dose. Olmesartan (5 and 10 mg/kg/day) decreased blood pressure to the WT mice level; however, the reduction of blood pressure in the night-time was stronger in azilsartan group. Expression of ACE2 mRNA was decreased in heart and kidney of hRN/hANG-Tg mice compared with WT mice. This decrease in ACE2 mRNA expression was attenuated by administration of azilsartan, but not by olmesartan treatment. The ratio of heart to body weight ratio was decreased in all azilsartan-treated groups, but this decrease was observed only in 10 mg/kg/day of olmesartan-treated group. Treatment with azilsartan even at lower dose increased the urinary excretion of Na.

Conclusion:
These results suggested that hypotensive effect of azilsartan may involve the activation of ACE2/Ang(1-7)/Mas axis with AT
1
receptor blockade. Further investigation will reveal the pathophysiological role of ACE2/Ang(1-7)/Mas axis in blood ptessure control and contribute to discuss further the possible drug effect of ARBs beyond class effect.
Abstract 6: Angiotensin II via Its Type 1 Receptor Up-regulates (Pro)renin Receptor Expression in Doca-salt Hypertension
Authors: Li Wencheng , Feng Yumei
Published: July 2021

We previously reported that brain (pro)renin receptor (PRR) expression levels are elevated in deoxycorticosterone acetate (DOCA)-salt induced hypertension; however, the underlining mechanism remains unknown. To address whether angiotensin (Ang II) type 1 receptor (AT1R) signals are involved in the regulation of PRR expression in DOCA-salt hypertension, C57Bl/6J mice were implanted with telemetry transmitters. After two weeks recovery, mice were treated with DOCA (50mg) or SHAM pellet, and supplied with 0.9% saline as drinking solution; at the same time, mice were ICV infused with artificial CSF or AT1R blocker losartan (3mg/kg/day) for 3 weeks. The mean arterial BP was significantly higher in DOCA-salt (132.3±6.3mmHg) compared to SHAM (100.2±2.3mmHg) mice. ICV infusion of losartan prevented the increase in BP (107.4±2.7mmHg) following DOCA-salt treatment. The PRR mRNA levels (fold change) were significantly increased in the paraventricular nucleus (PVN) of DOCA-salt (2.9±0.3) compared with SHAM mice (1.0±0.1, P<0.05). Interestingly, ICV infusion of losartan significantly attenuated PRR mRNA levels in the PVN (1.3±0.1) following DOCA-salt treatment (P<0.05). These data suggest a role of Ang II/AT1R in regulating PRR expression during DOCA-salt hypertension. A transcription factor prediction search showed cAMP response element-binding protein (CREB), activator protein-1 binding protein (AP-1), and NF-kB binding sites on the PRR promoter region. To test whether these Ang II/AT1R downstream transcription factors are involved in PRR regulation, Neuro-2A cells were treated with Ang II (100nM, 2 h) with or without CREB (CBP-CREB interaction inhibitor, 10μM), AP-1 (SR-11302, 10μM), or NF-κB (parthenolide, 10μM) inhibitors. PRR mRNA levels (fold change) were slightly but significantly increased (1.3±0.1 vs. vehicle, P<0.05) following Ang II treatment. CREB (0.8±0.2) or AP-1 (0.7±0.1) inhibitor abolished the increase in PRR mRNA induced by Ang II (P<0.01). The NF-kB inhibitor had no effect on Ang II-induced PRR mRNA elevation. In conclusion, Ang II via AT1R up-regulates PRR mRNA expression in the PVN of DOCA-hypertensive mice possibly through activation of CREB and AP-1 signaling pathways.
Abstract 605: ICU Blood Pressure Variability Correlates With The Nadir Of Respiratory Depression After Cardiac Surgery
Authors: Costa Anne S , Costa Paulo H , de Lima Carlos E , Padua Luiz E , Campos Luciana A , Baltatu Ovidiu C
Published: July 2021

Objective.
Coronary artery bypass graft surgery (CABG) is associated with postoperative respiratory depression. The primary endpoint of this study was the determination whether the blood pressure variability during the intensive care unit (ICU) is correlated with the nadir of postoperative respiratory function impairment.

Methods.
This prospective study evaluated 44 patients subjected to CABG with cardiopulmonary bypass (CPB). Mean arterial pressure (MAP) was monitored every 30 min for 3 days at the ICU. MAP variability was evaluated through: standard deviation (SD), coefficient of variation (CV), variation independent of mean (VIM), average successive variability (ASV) and SD of ASV. Respiratory function was assessed through maximal inspiratory (MIP) and expiratory (MEP) pressures and expiratory peak flow rate (EPFR) determined 1 day before surgery and on the postoperative days 3rd to 7th.

Results.
Respiratory parameters MIP, MEP and EPFR were significantly depressed postoperatively for 4, 4 and 5 days respectively. Patient adherence to EPFR monitoring was higher than for MIP and MEP. None of the perioperative parameters (volume of cardioplegia, CPB duration, aortic cross-clamp time, number of grafts) had any correlation with the postoperative respiratory depression. Of all MAP variability parameters, the ASV and SD of ASV had a significant good positive Spearman correlation (rho coefficients ranging from 0.45 to 0.65, p<0.01) with the nadir depression of EPFR for 5 days after cardiac surgery.

Conclusion.
Variability parameters ASV and SD of ASV of the MAP monitored at ICU may have predictive value for the depression of respiratory function after cardiac surgery as determined by EPFR.
Abstract 612: Differential Expression of the Estrogen Receptors GPR30 and ERa in the Kidney of the Diabetic Hypertensive mRen2.Lewis Strain
Authors: Chappell Mark C
Published: July 2021

Diabetes was induced in adult female and male mRen2.Lewis rats at 11 wk of age with a single dose of streptozotocin (STZ at 65mg/kg ip) dissolved in 0.1 M citrate buffer (diabetic); the control group received a single dose of 0.1 M citrate buffer pH 4.5 (nondiabetic). The rats were followed for 4 weeks without insulin replacement. Kidney cortex was lysed and centrifuged at 100,000g to generate cytosolic and membrane fractions. The cortical fractions were probed with antibodies to the Receptor levels for GPR30 in the membrane fractions and ER-α in both membrane and cytosolic fractions were quantified by protein immunoblot. Following detection, membranes were reprobed with mouse monoclonal anti-β-actin (1:5,000; Sigma) as a loading control, and bands were quantified by MCID densitometry software. All measurements are expressed as means ± SE. An unpaired Student’s
t
-test compared GPR30 and ER-α protein expression between the control and diabetic group as well as females and males groups in both cytosol and membranes fractions. The expression of GPR30 tended to be higher in both the intact female [0.40 ± 0.17 vs. 1.04 ± 0.29] and the male [0.32 ± 0.18 vs 0.61 ± 0.13] diabetic mRen2.Lewis rats. and increased in both diabetic females and males GPR30 showed higher levels in control females than males [1.21 ± 0.49 vs 0.76 ± 0.39]; however, it decreased in diabetic females compared to males [0.79 ± 0.27 vs 1.03 ± 0.27]. Moreover, the ER-α receptor in the cytosolic fraction was lower in the diabetics females [3.68 ± 1.30 vs 1.36 ± 0.27], but remained unchanged in males [2.09 ± 0.23 vs 2.33 ± 0.39]. The same happened in the membrane fractions where there was not difference between controls and diabetics males [0.73 ± 0.16 vs 0.63 ± 0.40] while in diabetic females the ER-α receptor levels increased [0.97 ± 0.17 vs 1.27 ± 0.06]. Cortical content of ER-α in the cytosol was significantly increased in control females compared to control males [1.06 ± 0.14 vs 0.47 ± 0.04; p = 0.007], although it remained unchanged between diabetic females and males [1.26 ± 0.24 vs 1.44 ± 0.62].
Abstract 613: Exercise Training Improves Cardiac Mitofusin 2 Expression In Diabetes
Authors: Jorge Luciana , Paulini Janaina , Silva Cleiton , Rampaso Rodolfo , luiz rafael , Lima Wesley , Scavasin Gabriele , Schor Nestor
Published: July 2021

Introduction:
DM increases the risk of developing cardiovascular disease, although the specific molecular mechanisms underlying DM are not well understood, perhaps the most important pathway regulating metabolism in muscle is mitochondrial biogenesis. The mitofusin 2 is a important protein to mitochondrial fusion. Additionally, muscle mitochondrial metabolism is regulated by a group of morphogenesis machinery proteins which are important for mitochondrial fusion and fission events and also for their independent effects on bioenergetics. The exercise training is a strategy for reversing the effects of mitochondrial dysfunction trough the regulation of mitochondrial protein transcription and biogenegis. The aim of this study was to verify if endurance exercise increases the expression of Mitofusin 2 in cardiac myocytes in experimental diabetes. Male Wistar rats were divided into 4 groups: control (C:8), control trained (CT=8), diabetic (D=8), diabetic trained (DT=8). DM was induced by STZ (50mg/kg). Trained groups were submitted to an exercise training (ET) protocol on a treadmill (8 wk). BPS, HR were analyzed using a data acquisition system (PowerLab). The ratio between heart weight and tibia length was used to determination of cardiac hypertrophy. The expression of protein mitofusin 2 was evaluated by western blotting. The BPS was similar between grups (CS:124, CT:128; DS:122; DT:130 mmHg), however the HR was decreased in the DS group (323bpm) and ET was able to normalize this (DT 342bpm ). DM decreased 23% of the cardiac mass, but ET prevented this reduction (DT 13%). The expression mft2 was reduced in the DS and the exercise normalized this expression.

Conclusion:
ET was able to avoid the cardiac muscle deterioration leading to the normalization of HR. This hemodynamic adaptation can be related with a bigger expression of mitofusin 2 and it could be associated with an improvement of cardiac metabolism. The importance of ET as a non pharmacological approach to treat the DM complications was demonstrated by the improvement of cardiac function and molecular mechanisms.
Abstract 617: Bisphenol A Inhibits GPR30-Mediated Dilation of Mesenteric Resistance Arteries
Authors: Lindsey Sarah , Bratton Melyssa , McLachlan John A
Published: July 2021

We previously showed that activation of the membrane estrogen receptor GPR30 decreases blood pressure in hypertensive ovariectomized mRen2.Lewis rats and acutely dilates mesenteric resistance arteries. These studies suggest that GPR30 plays a role in estrogen’s beneficial cardiovascular effects. Bisphenol A (BPA) is an endocrine-disrupting chemical found in most manufactured plastic products that also binds to GPR30 in the nanomolar range. Clinical studies show a significant correlation between elevated urinary BPA and increased diagnosis of cardiovascular diseases including hypertension. Therefore, we hypothesized that BPA may disrupt the vasodilatory effects mediated by the novel estrogen receptor GPR30. Second-order mesenteric arteries from 15 week-old Lewis females were denuded and mounted on a wire myograph. Arteries were preconstricted with 10 μM phenylephrine before assessing the response to increasing concentrations of the selective GPR30 agonist G-1 (0.001-3 μM). Pretreatment with 10 μM BPA significantly inhibited G-1-induced relaxation of denuded vessels (Figure, *P<0.01). In summary, BPA blocked the vasodilatory actions of G-1 in vascular smooth muscle, perhaps by competing for GPR30 and/or altering its downstream signaling. We conclude that human exposure to BPA may interfere with the protective estrogenic effects mediated by GPR30.
Abstract 625: Hypoxia-Induced sFlt-1 Production is Enhanced in Placental Villi from Obese MC4R Deficient Rats
Authors: Palei Ana C , Spradley Frank T , Granger Joey P
Published: July 2021

Although the etiology of preeclampsia (PE) remains unclear, evidence indicates that impaired cytotrophoblast invasion followed by placental ischemia/hypoxia promotes the release of placental anti-angiogenic factors, such as soluble fms-like tyrosine kinase-1 (sFlt-1), into the maternal circulation. sFlt-1 blocks the pro-angiogenic actions of vascular endothelial growth factor to elicit maternal endothelial dysfunction and ultimately hypertension and proteinuria. Moreover, a leading risk factor for PE is obesity; however, the mechanisms whereby obesity increases the risk for developing PE are unknown. Our aim was to evaluate circulating and placental sFlt-1 levels in a genetic rodent model of obesity, the melanocortin-4 receptor
deficient
rat (MC4R+/-). Additionally, we examined the effect of obesity on hypoxia-induced sFlt-1 production in placental villous explants. At gestational day 19, body weight (357±5 vs. 331±11 g) and visceral fat weight (15.3±0.4 vs. 9.2±0.4 g) were higher in MC4R+/- obese pregnant rats (N=7) over MC4R+/+ lean pregnant rats (N=7), whereas mean arterial pressure was similar between groups (MC4R+/-: 110±4 vs. MC4R+/+: 102±2 mmHg). The levels of sFlt-1 in plasma (MC4R+/+: 228±75 vs. MC4R+/+: 141±34 pg/mL) and whole placenta (MC4R+/-: 0.86±0.06 vs. MC4R+/+: 0.82±0.04 pg/mg) were comparable between groups. Similarly, there was no difference in sFlt-1 secretion from 48 h cultures of placental villi explanted from MC4R+/- (1969±176 pg/mg) vs. MC4R+/+ (1408±188 pg/mg) under normoxic conditions (6% oxygen). However, in the face of hypoxia (1% oxygen), there was more pronounced sFlt-1 secretion from MC4R+/- obese rats than MC4R+/+ lean counterparts (2160±233 vs. 1311±120 pg/mg, respectively; P<0.05). In conclusion, we found that sFlt-1 levels were not disrupted in obese pregnant rats during normal pregnancy; however,
in vitro
studies with placental villi from obese rats showed enhanced hypoxia-induced sFlt-1 secretion. Together these findings suggest that placental ischemia-induced endothelial dysfunction and hypertension may be exaggerated by obesity.
Abstract 631: Big Angiotensin-25 (Bang-25): A Novel Glycosylated Angiotensin-related Peptide Isolated From Human Urine
Authors: Nagata Sayaka , Kitamura Kazuo
Published: July 2021

The renin-angiotensin system (RAS) plays key roles in the regulation of blood pressure and body fluid dynamics. It is now recognized that a wide variety of tissues and organs, including the heart, vasculature, kidney and nervous system, among others, contain a local tissue RAS, which exerts autocrine/paracrine effects and acts independently of the systemic RAS. In 2006, we isolated and characterized proangiotensin-12, a component of the tissue RAS in rat small intestine. Similar angiotensin-related peptides had never been reported in humans. When we screened human urine gel filtration fractions for bioactive peptides using an antibody raised against the N-terminal portion of Angiotensin II (Ang II), we found a highly immunoreactive peptide with an apparent molecular weight of about 5,000. Therefore, we purified this peptide from 5.5 L of human urine using ion-exchange, gel-filtration, and affinity chromatography, and finally reverse-phase high-performance liquid chromatography (RP-HPLC) steps. We isolated and identified a novel Aogen-derived peptide, Big angiotensin-25 (Bang-25), which is composed of 25 amino acids and is N-glycosylated on its 14th amino acid (Asn) and has a cysteine linked to its 18th amino acid (Cys). We then assessed the distribution of Bang-25 in tissues by immunostaining with an antiserum raised against the C-terminal portion of the peptide. We found that Bang-25 was abundantly expressed in a number of human tissues, including kidney, heart, adrenal gland, pancreas and placenta. In the kidney, Bang-25 is localized predominantly to podocytes. Then, compared with angiotensinogen, Bang-25 is rapidly cleaved by chymase to Ang II, but is resistant to cleavage by renin. In the present study, we have isolated and identified a novel Angiotensin-derived peptide, Bang-25, which is composed of 25 amino acids and is N-glycosylated on its 14th amino acid (Asn) and has a cysteine linked to its 18th amino acid (Cys). The identification of Bang-25 suggests the existence of a RAS processing cascade different from the renin-catalyzed cleavage of Angiotensin to Ang I, and provides a potential target for assessing tissue RAS status and for the development of new therapeutic approaches to related diseases.
Abstract 634: Suppression of Ang II Inhibits Sodium Retention During Mental Stress
Authors: Harshfield Gregory A , Hanevold Coral , Ortiz Luis , Nwobi Obioma I , Johnson Maribeth , Stewart Deborah L
Published: July 2021

Background:
We hypothesized that stress-induced increases in Ang-II would increase the retained sodium load over the course of a day in a significant percentage of African-Americans (AAs).

Methods:
We tested this hypothesis with a double blind placebo-controlled trial which examined the effect of an angiotensin receptor antagonist blocker (irbesartan) on the pressure natriuresis response to one hour of mental stress induced by a competitive video game task in 93 healthy, normotensive AAs with a mean age of 26 years. The 3-hour protocol consisted of a 1-hour stress period preceded and followed by a 1-hour rest period. Blood and urine were collected hourly and blood pressure at 15 minute intervals. The subjects were divided into those who increased (excreters, upper panel) or decreased (retainers, lower panel) U
Na
V with stress in the placebo condition.

Results:
The ARB increased the change in U
Na
V during stress by 10.2 mEq, or approximately 235 mgs in Retainers but had no effect in Excreters. The ARB also had a beneficial effect on the blood pressure levels in Retainers but not Excreters, lowering levels throughout the protocol in this group.

Conclusions:
Assuming 4 episodes of stress during a day, the additional sodium load induced by Ang II would be approximately 1,000 mgs, which would increase the average intake by an estimated one third. From a prevention perspective, these individuals would need to reduce their sodium intake by a third to compensate for the amount of sodium reabsorbed during episodes of mental stress throughout the day.

Figure.
Effect of angiotensin receptor blocker on sodium excretion (UnaV) in response to stress in AA excreters vs. retainers.
Abstract 641: Expression Of GLUT4 In Vascular Smooth Muscle Affects Endothelial Function In Hypertension.
Authors: Atkins Kevin B , Saha Jharna , Brosius Frank C
Published: July 2021

Expression of GLUT4 is decreased in arterial smooth muscle of hypertensive rats and mice, and total body overexpression of GLUT4 in mice prevents enhanced arterial reactivity. To demonstrate that the effect on vascular response to GLUT4 overexpression is vascular rather than systemic in origin we utilized smooth muscle-specific GLUT4 transgenic mice (SMG4). GLUT4 expression in aortae of SMG4 compared to WT mice was increased 2-3 fold. Adult wild-type (WT) and SMG4 mice were made hypertensive or not through implantation of angiotensin II (AngII; 1.4mg/kg/d for 2 wks) or vehicle containing osmotic mini-pumps. Both WT and SMG4 mice AngII-treated mice exhibited significantly increased systolic blood pressure. In AngII-treated WT mice (WT-AngII) aortic GLUT4 expression was significantly decreased, whereas GLUT4 expression in aortae of AngII-treated SMG4 mice (SMG4-AngII) was maintained. The phosphorylation of ERM and MYPT1(Thr850) were significantly increased in aortae of WT-AngII compared to WT-Sham and SMG4-AngII mice. Responsiveness to the contractile agonists, phenylephrine, 5-HT, and PGF
2
was significantly increased in endothelium-intact aortic rings from WT-AngII mice, but remained normal in aortae of SMG4-AngII mice. Following pretreatment with Rho-kinase inhibitor Y-27632, relative inhibition of contractility to 5-HT was equal in aortae from WT-AngII and SMG4-AngII-treated mice. With endothelial denudation, contractility to 5-HT was equally enhanced in aortae of WT-AngII and SMG4-AngII-treated mice. Interestingly, whereas acetylcholine stimulated relaxation was significantly decreased in aortic rings of WT-AngII mice, relaxation in rings from SMG4-AngII mice was not significantly different from WT or SMG4. These results demonstrate an interesting phenomenon whereby decreased expression of GLUT4 in vascular smooth muscle leads to an endothelial dysfunction that not only impairs relaxation, but also enhances contractility.
Abstract 66: Altered Vascular Reactivity in Mice Overexpressing Adipocyte Mineralocorticoid Receptors - Role of Oxidative Stress and Rho Kinase
Authors: Nguyen Dinh Cat Aurelie , Callera Glaucia E , Antunes Tayze T , Montezano Augusto C , He Ying , Jenkins Carol , Carter Anthony , Jaisser Frederic , Touyz Rhian M
Published: July 2021

Aldosterone (aldo) plays a role in obesity and cardiovascular diseases, such as hypertension. We previously demonstrated that adipocyte-derived factors regulate vascular function and vascular smooth muscle cells signaling. Moreover, adipocytes express aldosterone synthase (CYP11B2) and produce aldo. The mineralocorticoid receptor (MR), which is responsible for aldo signaling, is also found in these cells, but its role in regulating adipose tissue interactions with the vasculature is unknown. In this study, we investigated mechanisms whether MR activation in adipocytes regulates vascular reactivity. Conditional transgenic mice that overexpress MR in an adipocyte-specific manner were studied. Vascular reactivity of resistance mesenteric arteries to acetylcholine (Ach), sodium nitroprusside and phenylephrine (Phe), in the absence or presence of fat conditioned medium (Fcm) from control and adipocyte overexpressing MR (MROE) mice, was performed by myography. In basal conditions, endothelial dysfunction was not observed in MROE or control (Ctr) mice. However, exposure of arteries from control mice to Fcm from MROE mice induces endothelial dysfunction (Ach 10
-6
M: 77.5±9.6% no Fcm vs. 49.8±7.5% Fcm, p<0.05), an effect blocked by N-acetyl-cysteine (an antioxidant) (Ach 10
-6
M: 82.2±6.6%). Resistance arteries from MROE mice had decreased Phe-induced contraction, compared to control mice (Phe 10
-5
M: 2.7±0.2 mN/mm Ctr vs. 1.7±0.2 mN/mm MROE, p<0.05). Rho Kinase activity, which regulates vascular contraction, is decreased in arteries and adipo tissue from MROE (mesenteric arteries, Ctr: 100±16.2% vs. MROE: 31.1±6.1%, arbitrary units, p<0.01; adipose tissue, Ctr: 100±12.6% vs. MROE: 51.3±9.3%, arbitrary units, p<0.01). In conclusion, MR in adipocytes may play an important role in the regulation of vascular function, through redox-sensitive pathways and activation of Rho kinase. Our study identifies novel mechanisms linking vascular/adipose tissue biology and aldo/MR activation, which may be particularly important in vascular dysfunction associated with hypertension and hyperaldosteronism.
Abstract 84: Deficiency of Lymphocyte-Specific Adaptor Protein, LNK, Exacerbates Angiotensin II-Induced Hypertension and Inflammation
Authors: Saleh Mohamed A , Harrison David G , Madhur Meena S
Published: July 2021

Lymphocyte-specific adaptor protein, LNK, is a negative regulator of hematopoiesis and endothelial cell signaling. Several large-scale genome wide association studies have identified a non-synonymous single nucleotide polymorphism in exon 3 of LNK, also known as SH2B3, to be positively associated with both systolic and diastolic blood pressure. The mechanism by which LNK contributes to blood pressure regulation is unknown. As LNK is a negative regulator of cytokine signaling and cell proliferation, we hypothesized that loss of LNK would exacerbate angiotensin II (AngII)-induced hypertension and its associated inflammation. We found that mice deficient in LNK (LNK
-/-
) had similar baseline blood pressures compared to wild type C57Bl/6 (WT) mice. However, after 2 weeks of AngII infusion, LNK
-/-
mice exhibited a greater increase in systolic blood pressure (SBP) and decrease in HR compared to WT mice as measured by radiotelemetry (SBP: 196.0±5.8 vs 174.3±4.4 mmHg, p<0.01; HR: 533.3±14.4 vs 612.2±2.0 beats/min, p<0.05, n=6-7). Renal inflammation was examined by immunostaining and flow cytometry. At baseline, LNK
-/-
mice had almost 4-fold more CD3
+
T cells in the renal medulla compared to WT mice (56.3±8.2/mm
2
vs 14.8±3.9/mm
2
, p<0.01, n=3-4), and this was markedly increased in response to 2 weeks of AngII infusion (134.0±27.0/mm
2
vs 32.5±5.9/mm
2
, p<0.01, n=3-4). Flow cytometry for total renal lymphocytes and activated macrophages demonstrated increased numbers of these cells both at baseline and in response to AngII infusion in the LNK
-/-
mice compared to WT mice. Cytokine analysis performed on the culture supernatants of splenic T cells demonstrated that baseline levels of interleukin 17A (IL17A) and tumor necrosis factor alpha were higher in LNK
-/-
mice compared to WT mice. The pro-inflammatory cytokine, IL17A, was further increased in LNK
-/-
mice in response to AngII infusion. Taken together, these data demonstrate that LNK inhibits AngII-induced hypertension and inflammation and might serve as a novel therapeutic target for this widespread disease.
Abstract 013: Chronic Intra-Renal Insulin Infusion Increases Mean Arterial Pressure on a Background of Mild Angiotensin II Hypertension
Authors: Brands Michael W , Staruschenko Alexander , Blazer-Yost Bonnie L , Alaisami Rabei , Duggan Daniel
Published: July 2021

We reported that chronic intra-renal insulin infusion in diabetic dogs reversed the natriuresis and diuresis caused by 6 days of hyperglycemia. However, the sustained sodium-retaining action was not accompanied by hypertension. This study tested whether intra-renal insulin infusion would increase blood pressure in diabetic dogs with chronic angiotensin II (AngII) hypertension. Seven dogs were chronically instrumented and divided into D (diabetes) and Dir (D + intra-renal insulin) groups. Alloxan was administered to all 7 dogs, and continuous iv. insulin replacement therapy was used to maintain them at normal blood glucose. All dogs also were infused with AngII (3 ng/kg/min, iv) continuously. After 3 days of control measurements, with normal blood glucose, MAP averaged 135±3 and 129±3 mmHg in D and Dir dogs, respectively. Six days of hyperglycemia (diabetes) was induced in both groups by reducing the iv. insulin infusion dose. Intra-renal insulin at 0.3 mU/kg/min was initiated concurrently in the Dir dogs. MAP increased in the Dir group to an average of 141±4 mmHg by day 6 of diabetes. Moreover, Figure 1 shows the progressive separation in MAP compared to the D dogs, to an average difference of 19 mmHg by day 6 of diabetes. Renal blood flow (measured 24 hr/day along with MAP) increased in both groups, as did GFR. However, statistically significant differences were not achieved yet with these preliminary data. These results suggest that the chronic antinatriuretic effect of insulin in diabetes may have an AngII-dependent hypertensive action. The mechanism does not appear to be dependent on renal vasoconstriction, and may, therefore, be linked to effects on tubular sodium reabsorption.
Abstract 019: Vascular Smooth Muscle ADAM17 Contributes To Angiotensin II-induced Abdominal Aortic Aneurysm Formation But Not Hypertension In Mice
Authors: Tsuji Toshiyuki , Takayanagi Takehiko , Elliott Katherine , Obama Takashi , Crawford Kevin , Rizzo Victor , Eguchi Satoru
Published: July 2021

Enhancement of the renin angiotensin II (AngII) system has been implicated in the development of abdominal aortic aneurysm (AAA). However, detailed molecular mechanism(s) by which AngII promotes AAA remain uncertain. We have demonstrated the critical role of a metalloprotease, ADAM17, in AngII-induced EGFR transactivation and subsequent hypertrophy in vascular smooth muscle cells (VSMC). In caveolin 1-/- mice, AAA formation induced by AngII plus beta-aminopropionitrile (BAPN), a lysyl oxidase inhibitor, was attenuated. The attenuation of AAA formation was associated with suppression of ADAM17 induction and EGFR activation. Others have reported that systemic ADAM17 silencing attenuated CaCl2-induced AAA formation in mice. However, the cell type specific mechanism that is mediating the deleterious effect of ADAM17 in AAA is not well understood. Here, we tested our hypothesis that VSMC ADAM17 activation is required for AngII-promoted AAA formation using ADAM17flox/flox mice bred with sm22a Cre mice. 8 week old mice were co-infused with AngII 1000 ng/kg/min (4w) and BAPN 150 mg/kg/day (2w) or control saline (4w), and AAA formation was evaluated by echo (internal diameter) and measurement (external diameter) of the aortae. In control Cre-/- mice with the co-infusion, 52.4% (11/21) were dead due to aortic rupture/dissection. All surviving Cre-/- mice with co-infusion had AAA with max external/internal diameter (mm) of 2.18±0.55/1.75±0.33 vs 1.01±0.22/1.06±0.02 with saline infusion (p<0.01). In contrast, VSMC ADAM17 deficient Cre+/- with co-infusion did not die or develop AAA. The max external/internal diameter (mm) of AA in Cre+/- with co-infusion was 1.03±0.11/1.05±0.05 vs 1.01±0.12/1.27±0.21 with saline infusion. In contrast, both Cre-/- and +/- mice with the co-infusion developed hypertension assessed by telemetry (MAP mmHg: 161±15 vs 154±12). The ADAM17 deletion was also associated with less EGFR activation, ER/oxidative stress and extravascular fibrosis/matrix deposition. In conclusion, VSMC ADAM17 appears to be a critical metalloprotease contributing to AAA formation but not hypertension induced by AngII + BAPN. The mechanism by which VSMC ADAM17 promotes AAA seems to involve activation of EGFR and induction of ER/oxidative stress.
Abstract 025: Disruption of Shroom3 contributes to impaired glomerular podocyte function
Authors: Yeo Nan Cher , O'Meara Caitlin C , Veth Kerry N , Tomar Ritu , Flister Michael J , Drummond Iain A , Lazar Jozef , Link Brian A , Jacob Howard J
Published: July 2021

SHROOM3 has been associated with chronic kidney disease by genome-wide association studies (GWAS), yet its role in renal function and diseases was completely unknown. Here, we leveraged the integrated physiological genomic approach in rat models and zebrafish to dissect the renal function of SHROOM3 and its contribution to renal impairments. Congenic mapping and sequence analysis in rats suggested Shroom3 was a strong positional candidate gene. Transferring a 14.50-21.40 Mbp region of the BN (Brown Norway) chromosome 14 containing the Shroom3 gene onto the FHH (Fawn-Hooded Hypertensive) background significantly lowered the level of albuminuria (31.07±3.98 vs 51.92±5.69 mg/day; P=0.001), glomerular permeability to albumin (0.48±0.02 vs 0.59±0.02; P<0.001), and glomerular sclerosis (0.72±0.03 vs 1.82±0.05; P<0.001). The FHH Shroom3 allele contains 13 amino acid variants compared to BN rat. In vivo injection of the wild-type BN Shroom3 mRNA, but not the FHH Shroom3, rescued the glomerular leakage induced by endogenous knockdown of shroom3 in zebrafish, suggesting that the FHH Shroom3 allele is defective and likely contributes to glomerular impairments seen in the FHH rat. Functional screening of the 13 FHH Shroom3 variants identified a mutation, which decreased Shroom3 binding affinity to actins (5.85±2.69 vs 52.28±16.18; P<0.05) and consequently, impaired glomerular permeability. These results demonstrate that Shroom3-mediated interaction with actin is a crucial mechanism underlying the control of glomerular filtration barrier. Furthermore, we showed that podocyte-specific shroom3 disruption in zebrafish caused glomerular impairments and podocyte effacement, indicated by reduced foot process number (2.85±0.07 vs 4.2±0.35; P<0.001) and increased foot process size (319.85±19.42 vs 164.39±8.24 nm; P<0.001). Taken together, these experiments provide the first direct demonstration that Shroom3 is functionally involved in renal pathophysiology by the control of glomerular podocyte function.
Abstract 032: Carotid Chemoreceptor Activation Blunts The Hypotensive Response Caused By The Electrical Stimulation Of The Carotid Sinus In Conscious Rats
Authors: Katayama Pedro L , Castania Jaci A , Fazan Rubens , Salgado Helio C
Published: July 2021

The mechanisms involved in Baroreflex Activation Therapy (BAT) in patients with resistant hypertension require better understanding. It was shown that electrical stimulation of the carotid sinus (ESCS), in conscious carotid body-denervated rats, caused bradycardia and greater hypotensive response when compared with intact control rats. In the current study the activation of the chemoreceptors due to ESCS, in conscious rats, was examined in the absence of the carotid baroreceptors. Wistar rats with unilateral denervation of the right carotid chemoreceptors were divided into three groups: 1) control (CONT, n=7); 2) bilateral carotid chemoreceptor denervation (CD, n=7); 3) unilateral denervation of the left carotid baroreceptors (BD, n=4). Under ketamine/xylazine anesthesia bipolar electrodes were implanted around the left carotid sinus combined with arterial and venous catheters into the femoral vessels. On the next day, after basal hemodynamic recordings, the animals received three ESCS (5V, 1 ms) with 15 Hz, 30 Hz and 60 Hz, applied randomly for 20s. Carotid chemoreceptors denervation was confirmed by the lack of hemodynamic responses after the administration of KCN (40 μg iv). The efficacy of left carotid baroreceptor denervation was confirmed by the absence of hemodynamic responses to changes in the left carotid sinus pressure ranging from 60 mmHg to 180 mmHg. The results showed that ESCS was efficient to cause greater hypotensive responses in the CD as compared with the CONT group at 60 Hz (-37 ± 6 vs -19 ± 3 mmHg) and to cause hypertensive responses in the BD group at 30 Hz and 60 Hz (15 ± 2 and 19 ± 2 mmHg). ESCS caused no alteration of the heart rate in the CONT but caused significant bradycardia in the CD group at 30 Hz and 60 Hz (-31 ± 11 and -35 ± 12 bpm) and in the BD group at 15 Hz, 30 Hz and 60 Hz (-38 ± 6, -37 ± 6 and -34 ± 4 bpm). These data demonstrated that carotid chemoreceptor activation in the absence of the carotid baroreceptors caused hypertension and bradycardia, indicating that when the baroreceptors are intact, the chemoreceptors blunt the hypotensive response caused by ESCS. These findings provide important information for the clinical studies using BAT in patients with resistant hypertension and/or heart failure.
Abstract 037: Pancreatic-Angiotensin Type 1a Receptor Deficiency Prevents Angiotensin II-Mediated Reductions In Glucose-Stimulated Insulin Secretion From Isolated Islets Of Obese Mice.
Authors: Shoemaker Robin , Cassis Lisa
Published: July 2021

Objective:
Diet-induced obesity promotes type 2 diabetes (T2D). Drugs that inhibit the renin-angiotensin system (RAS) have been demonstrated in clinical trials to decrease the onset of T2D. Pancreatic islets have been reported to possess components of the renin-angiotensin system (RAS), including angiotensin type 1a receptors (AT1aR). Previously, we demonstrated that mice made obese from chronic consumption of a high-fat diet (HF) have marked elevations in systemic concentrations of angiotensin II (AngII). We tested the hypothesis that pancreatic-specific deletion of the AT1aR would improve glucose-stimulated insulin secretion (GSIS) from isolated islets of mice with diet-induced obesity.

Methods and Results:
In preliminary studies, we demonstrated that GSIS from islets isolated from obese mice was markedly diminished in the presence of AngII compared to vehicle (VEH) (VEH, 0.94 ± 0.22; AngII, 0.017 ± 0.15 fold increase over basal; P<0.05). A mouse model of pancreatic-AT1aR deficiency was created using

AT1aR
fl/fl

mice on a C57BL/6 background bred to transgenic Cre mice expressing the pdx-1 promoter to generate pancreatic AT1aR-deficient mice (

AT1aR
pdx

) and littermate controls (

AT1aR
fl/fl

). AT1aR mRNA expression was markedly decreased in whole pancreas of

AT1aR
pdx

mice (

AT1aR
fl/fl

, 2.24 ± 0.79;

AT1aR
pdx

, 0.53 ± 0.24 ΔΔ Ct AT1aR/18S; P < 0.05). Male, 8-week old

AT1aR
fl/fl

and

AT1aR
pdx

mice were fed a HF diet (60% kcal as fat) for 17 weeks. GSIS from isolated islets of HF-fed

AT1aR
fl/fl

mice was significantly reduced in the presence of AngII (10nM) compared to VEH (VEH, 229 ± 43; AngII, 129 ± 43 ng insulin/ng protein; P<0.05). Moreover, incubation of HF-fed islets from

AT1aR
fl/fl

, but not

AT1aR
pdx

mice, with losartan (1μM) prevented AngII-induced reductions in GSIS (AngII + losartan, 244 ± 118 ng insulin/ng protein). However, at 17 weeks of HF feeding there was no significant effect of pancreatic AT1aR deficiency on glucose tolerance.

Conclusions:
These results demonstrate that AngII markedly reduces glucose-stimulated insulin secretion from pancreatic islets of obese mice through an AT1aR-mediatd mechanism. Further studies are required to determine if pancreatic AT1aR influence the decline of insulin secretion during the progression of T2D.
Abstract 041: Distinct populations of cell derived microvesicles in Angiotensin II-induced hypertension
Authors: Erdbruegger Uta , Rudy Christine , Lannigan Joanne , Gigliotti Joseph , Chechova Sylvia , Le Thu
Published: July 2021

Background:
Hypertension (HTN) is a leading risk factor of cardiovascular diseases. Its pathogenesis is poorly understood, but activation of the renin angiotensin system is thought to be a key event. Vascular damage is an early manifestation of HTN. There are currently no available clinical biomarkers for early detection of vascular damage. Circulating microvesicles (MVs) have gained significant attention as potential novel biomarkers for vascular injury. These vesicles are less than 1 micron in size and carry markers of the parent cell. We hypothesized that MVs of endothelial and leukocyte origin are elevated in angiotensin II (AII) induced-HTN and show a distinct phenotype depending on the duration of HTN.

Methods:
Mice were treated with AII (400ng/kg/min) via mini-osmotic pumps for 2 and 4 weeks (wks). Systolic blood pressure (SBP) was measured using tail-cuff manometry. Enumeration and phenotyping of MVs were determined in platelet poor plasma using imaging flow cytometry and the following surface markers: E- Selectin (CD62E), Endoglin (CD105), VE Cadherin (CD144), Annexin 5 (AV), Platelets (CD41), P-Selectin (CD62E), leukocytes (CD45).

Results:
Compared to untreated controls (n=5), AII treated mice (n=5) had an increase in SBP by 30mmHg (p=0.02), and significantly elevated total counts of AV negative (AV-) and positive MVs (AV+) (p=0.04 and 0.06 respectively) after 2 wks. Endothelial derived MVs were also significantly elevated after 2 wks (AV+ and AV- CD144+ (p=0.023), AV+ and AV-CD62E+ (p=0.023), AV+ and AV-CD105+ (0.023), AV+ and AV- CD144+ (p=0.04)). However, after 4 wks of AII-induced HTN, only AV-CD144+ MVs remained significantly elevated. In contrast, leukocyte derived MVs (CD45+) were significantly increased after 2 wks, and remained significantly elevated after 4 wks. Platelet derived MVs were not significantly elevated at either time point.

Conclusions:
Distinct populations of endothelial and leukocyte derived MVs are elevated at different time points during AII-induced HTN. The changing profiles of the MVs may reflect an evolving pathophysiologic response of the vasculature. Further studies are needed to confirm these findings, and to determine the effect of the severity and etiology of HTN on the profiles of MVs.
Abstract 066: Cyclooxygenase-depended Signaling Via Thromboxane Prostanoid Receptors Mediates Endothelin-i Induced Ros Generation In Mesenteric Resistance Vessels From Mice Infused With Angiotensin Ii
Authors: Wilcox Christopher S , Wang Cheng , Wang Dan
Published: July 2021

Background:
Angiotensin II (Ang II) increases reactive oxygen species (ROS) and contractions to thromboxane and endothelin-1 (ET-1). Therefore, we tested the hypothesis that cyclooxygenase (COX) and/or thromboxane-prostanoid receptors (TP-Rs) mediate enhanced ROS generations with ET-1 in Ang II-infused mice.

Methods:
ROS was assessed by urinary 8-isoprotane(8-Iso) excretion and ethedium : dihydroetheldium (DHE) in mesenteric resistance arterioles (MRAs) from wild type (+/+) and littermate COX-1 -/- or TP-R -/- mice infused with vehicle or angiotensin II (Ang II, 400 ng/kg/min for 14 days) (n=6/ group, mean ±SEM).

Results:
Ang II infusion increased excretion (ng/mg creatine) of TxB
2
(1.3±0.1±1.0±0.1 in COX-1 +/+ mice and 1.9±0.1 vs 1.2±0.1 in TP-R +/+ mice, all P<0.05) and 8-Iso (2.1±0.2 vs 1.4±0.1 in COX-1 +/+ mice and 2.2±0.1 vs 1.4±0.2 in TP-R +/+ mice, all P<0.05) but not in COX-1 -/- or TP-R -/- mice. Ang II enhanced ROS generation (Δunit) with 10
-7
M ET-1 in MRAs from both +/+ mouse genotypes (1.7±0.2 vs 0.1±0.1 in COX-1 +/+ mice and 3.2±0.3 vs 0.1±0.1 in TP-R +/+ mice, all P<0.01). However, this increase in ROS was fully prevented in TP-R-/- mouse vessels (0.3±0.2 vs 0.2±0.1, NS) and in COX-1 +/+ mouse vessels after combined blockade of COX-1( 10
-5
M SC-560) and -2 (paracoxib 10
-5
M) (0.2±0.1 vs 0.1±0.1, NS) and in COX-1 -/- mouse vessels after paracoxib (0.2±0.1 vs 0.2±0.2, NS). Increased ROS generation was only partially prevented in COX-1 -/- mouse vessels (0.5±0.1 vs 0.2±0.2, P<0.05) or in COX-1 +/+ mouse vessels after blockade of COX-1 ( 0.7±0.1 vs 0.1±0.1, NS) or COX-2 (1.0±0.1 vs 0.1±0.1,P<0.05).

Conclusions:
Increased ROS generation with ET-1 in microvessels from Ang II infused mice depends on products of both COX-1 and -2 that activate TP-Rs. Thus, combined blockade of COX-1 and -2 or TP-Rs may prevent vascular ROS and its many complications during increased Ang II and ET-1, such as hypertension, hypoxia or shock.