bluuebunny/crossref_metadata_2025 huggingface dataset:
An Endogenous Ligand of α-1 Sodium Pump in Hypertensive Dahl Salt Sensitive Rats
Authors: Fedorova Olga V , Kolodkin Nikolai I , Lakatta Edward G , Bagrov Alexei Y
Published: March 2022

P97

Dahl salt sensitive rats (DS), due to a mutation of α-1 subunit of Na/K ATPase (NKA), exhibit impaired pressure natriuresis and on a high NaCl diet retain Na and increase their blood pressure (BP). Recently, we demonstrated that mammalian tissues contain marinobufagenin (MBG), a bufodienolide with a high affinity to α-1 subunit of NKA. The present study investigated possible roles of MBG and another endogenous NKA inhibitor, ouabain (Ou) in hypertension which develops in DS on a high NaCl intake. Dahl salt resistant rats (DR; n=12) and DS (n=12) were put on an 8% NaCl diet for 4 weeks. In DS the excretion of Ou peaked at week 1 of NaCl loading (78±20 pmol vs. 6.4±1.1 pmol in baseline; P<0.01)and then returned to baseline. In contrast, MBG exhibited a sustained increase (66±13 pmol at week 4 vs. 11±1 pmol in baseline; p<0.01) which paralled the sustained increases in systolic BP (174±10 mm Hg at week 4 vs. 110±2 mm Hg in baseline; p<0.01). No such effects occured in DR on an 8% NaCl intake. MBG-immunoreactive (MBG-ir) material was purified from urine of hypertensive DS via three steps of reverse phase HPLC and compared with ouabain and MBG from
Bufo marinus
toad for its ability of inhibit the NKA from rat kidney (which expresses only α-1 NKA) an the level of high- and low-affinity binding sites (Table). MBG acts as a selective inhibitor of ouabain-resistant α-1 NKA subunit, as one could expect from a putative natriuretic hormone. Our results sugest that in hypertensive DS, the α-1 ligand, MBG, is elaborated to promote natriuresis and contributes to the sustained BP elevation.
Improved Renal Function by Eta Receptor Blockade Is Associated with Reduced Renal Expression of Tgfβ and B FGF and Increased Activity of Mmp-2 in Shrsp
Authors: Tostes Rita C A , Touyz Rhian M , He Gang , Schiffrin Ernesto L
Published: March 2022

P104

Endothelin-1 (ET-1) receptor antagonists increase life span and improve renal function in salt-loaded stroke prone SHR (SHRSP). Mechanisms underlying these ET-1-dependent processes are unclear. We hypothesized that ET-1 induces renal damage by increasing expression of growth/inflammatory factors, important in renal fibrosis. Male 8 week-old SHRSP (n=24) were randomized in 3 groups: control group; high salt diet (4% NaCl) and salt diet plus an ET
A
receptor antagonist, BMS 182874 (40 mg/Kg/day). Systolic blood pressure (SBP) was measured weekly and renal function assessed 2 weekly. After 20 weeks treatment, rats were killed. Expression of renal ET-1 and ET
A
/ET
B
receptor mRNA was evaluated by RT-PCR, renal expression of transforming growth factor β1 (TGF-β1) and basic fibroblast growth factor (bFGF) were determined by Western blot and, metalloproteinase (MMP-2) activity was measured by gelatine-enzymography. SBP increased to ∼ 240 mmHg in salt-loaded rats. BMS treatment had a small, but significant BP lowering effect and delayed progression and severity of renal dysfunction. In salt-loaded SHRSP renal ET-1 mRNA expression was increased (1.6±0.1vs control 1±0.1; p<0.05), and ET
A
receptor mRNA expression was decreased (0.7±0.1 vs control 1±0.1; p<0.05). ET
B
subtype mRNA expression was unchanged. BMS treatment did not reverse these changes. Salt-loaded SHRSP exhibited increased renal expression of TGF-β1 (10.4±1SL-SHRSP vs 1±0.4 control, p<0.05) but not of bFGF (1.2±0.1 vs control 1±0.02) and augmented activity of MMP-2 (4.8±1.6 vs control 1±0.3, p<0.05). Treatment with BMS decreased expression of both TGF-β1 (6±0.4, p<0.05) and bFGF (0.6±0.1, p<0.05), and reduced MMP-2 activity (0.3±0.1). These data suggest that severe hypertension and renal dysfunction in salt-loaded SHRSP is associated with increased expression of renal ET-1 and growth factors. These effects were ameliorated by BMS treatment. In conclusion, nephroprotection by ET
A
receptor blockade may be mediated, in part, by normalizing expression of growth factors and restoring MMP2 activity in experimental models of severe hypertension.
Aortic Stiffness Versus Framingham Score as Independent Predictors of Coronary Heart Disease in Hypertensive Patients
Authors: Laurent Stephane , Tropeano Anne I , Boutouyrie Pierre
Published: March 2022

P113

Background
: Although various studies reported that pulse pressure, an indirect index of arterial stiffness, was an independent risk factor for coronary heart disease (CHD), a direct relationship between arterial stiffness and CHD remained to be established in patients with essential hypertension.
Methods
: A cohort of 1212 essential hypertensives patients, who had a measurement of arterial stiffness between 1980 and 1996, was studied. At entry, aortic stiffness was assessed from the carotid-femoral pulse wave velocity (PWV). A coronary disease prediction algorithm (Wilson P et al. Circulation 1998), based on the Framingham Heart Study (Framingham algorithm, FA), was calculated according to categories of sex, age, blood pressure, cholesterol, diabetes, and smoking, but not PWV. The ranges of FA and PWV values, included within the 1st and the 9th deciles, were 2-11 points and 8-16 m/s, respectively. CHD included fatal and non fatal myocardial infarction, coronary revascularization, and angina pectoris. The Cox proportional hazard regression model was used to estimate the relative risk (RR) of CHD.
Results
: Mean age at entry was 52±13 years (mean±SD). The mean delay to the first CHD event was 69±63 months. Seventy-three fatal and non fatal CHD events occurred. In this French population, the FA significantly predicted the occurence of CHD in the whole population (RR=1.10 (1.03-1.17) for 1 point of FA, P<0.01), but not in patients devoid of cardiovascular disease (other than hypertension) at entry. PWV was a significant independent predictor of CHD not only in the whole population (RR=1.07(1.02-1.12) for 1 m/s PWV, P<0.01), but also in patients devoid of previous cardiovascular disease at entry (primary events) (RR=1.11 (1.02-1.20), P=0.01). The predictive value of PWV remained unchanged after adjustment for FA and pulse pressure.
Conclusion
: This study provides the first direct evidence that aortic stiffness is an independent predictor of CHD in patients with essential hypertension. Aortic stiffness alone has a similar predictive value than the Framingham algorithm for CHD, and a better predictive value for primary CHD events.
Mechanical Forces and Carotid Atherosclerosis in Patients with Risk Factors for Atherosclerosis
Authors: Kohara Katsuhiko , Jiang Yinong , Igase Michiya , Miki Tetsuro , Hiwada Kunio
Published: March 2022

P115

Mechanical stresses to the arterial wall were evaluated in the carotid artery in 117 patients with risk factors for atherosclerosis including hypertension, dyslipidemia, and diabetes mellitus. Circumferential wall tension and shear stress were evaluated using Laplace’s law and Poiseuillean‘s parabolic model of flow velocity distribution. Arterial strain was also evaluated as the circumferential wall stretch. Wall tension was significantly related to BMI (r=0.40, p<0.0001), systolic pressure (r=0.79, p<0.0001), triglyeride (r=0.19, p<0.05) as well as HDL cholesterol (r=-0.22, p<0.05), while shear stress showed significant relationships with age (r=-0.34, p<0.001), pulse pressure (r=-0.27, p<0.01) and HDL-cholesterol (r=0.19, p<0.05). On the other hand, arterial strain did not correlate with any risk factor. Carotid intima-media thickness (IMT) showed a significant positive correlation with peak wall tension (r=0.44, p<0.0001) and mean wall tension (r=0.31, p<0.001), and a significant negative correlation with peak systolic shear stress (r=0.34, p<0.001) and mean shear stress (r=-0.42, p<0.0001), while there was no significant relationship between arterial strain and IMT. Stepwise regression analysis revealed that low shear stress and high wall tension were independently associated with IMT in the total subjects with risk factors. Furthermore, it revealed that wall tension was independently associated with IMT in hypertensive patients, while shear stress was an independent determinant of IMT in normotensive subjects. These findings indicate that both wall tension and shear stress are associated with carotid atherosclerosis in subjects with risk factors for atherosclerosis. However, the degree of contribution of mechanical forces to atherosclerosis differs among risk factors.
Endothelial Dysfunction in Salt Sensitive Hypertension
Authors: Bragulat Ernesto , Sierra Alejandro De La , Antonio Maria T , Coca Antonio
Published: March 2022

P129

The aim of the study was to evaluate endothelial function in a group of essential hypertensive patients classified on the basis of their salt sensitivity. Forty hypertensive patients were placed on two 7-day periods of low (50 mmol/day) and high (250 mmol/day) salt intakes. Salt sensitivity was defined as a significant rise (p<0.05) in 24-hour mean blood pressure (MBP), from low to high salt intake, measured by ambulatory blood pressure monitoring. Endothelial function was determined by the increase in the forearm blood flow (FBF) (strain-gauge plethysmography) to intrabrachial infusion of increasing doses of acetylcholine and sodium nitroprusside, before and after the addition of the NO synthase inhibitor, L-NMMA. Nineteen hypertensive patients significantly increased MBP with high salt intake (from 105 ± 2.6 to 112.5 ± 2.5 mmHg)and were considered salt sensitive (SS). In contrast, 21 patients did not modify their MBP after high salt intake (from 102 ± 3 to 100 ± 3 mmHg) and were diagnosed as having salt resistant hypertension (SR). The vasodilation response to acetylcholine was significantly blunted (p=0.001) in SS patients (FBF rose from 4.5 ± 0.2 to 20.6 ± 1.4 mL/100mL of forearm tissue [FT] per minute) when compared to SR (FBF rose to 4.4 ± 0.3 to 28.4 ± 1.7 mL/100mL FT per minute). Maximal acetylcholine-dependent vasodilation was inversely correlated with the MBP increase with high salt intake (r=-0.47; p=0.003). Sodium nitroprusside-related vasodilation was similar in SS and SR patients (from 4.4 ± 0.1 to 22.4 ± 1.1 mL/100mL/min in SS and from 4.5 ± 0.2 to 23.9 ± 1.3 mL/100mL/min in SR; p=0.4). In SS patients, L-NMMA infusion cause a decrease in baseline FBF (4.5 ± 0.2 to 3.2 ± 0.1 mL/100mL/min, whereas the response to acetylcholine was not significatively affected (from 3.2 ± 0.1 to 18.1 ± 1.8 mL/100mL/min) In SR patients, L-NMMA infusion also decreases baseline FBF (from 4.3 ± 0.2 to 3.1 ± 0.1 mL/100mL/min) and the response to acetylcholine was impaired in this group(from 3.1 ± 0.1 to 20.5 ± 1.4 mL/100mL/min). We conclude that salt-sensitive hypertension is associated with a higher degree of endothelial dysfunction. This deficient vasodilation may be secondary to an alteration in the L-arginine-NO pathway.
Reduction of Homocyst (e) Ine to Subnormal Levels Restores Endothelial Function in Normohomocyst (E) Inemic Habitual Smokers: Effect of Folic Acid Supplementation
Authors: Iida Shuji , Matsuoka Hidehiro , Fukami Kei , Satoh Akira , Okuda Seiya , Imaizumi Tsutomu
Published: March 2022

P131

Chronic administration of folic acid decreases plasma levels of homocyst(e)ine (Hcy) in hyperhomocyst(e)inemic subjects. Folic acid augments NO release and eliminates superoxide anion production in vitro. In chronic smokers, endothelial function is impaired possibly due to oxidative stress. Accordingly, we examined whether folic acid supplementation improves endothelial function in chronic smokers. We administrated folic acid (20 mg/day, po) or placebo for one week in normohomocyst(e)inemic habitual smokers and age-matched controls and examined flow-mediated vasodilation of the brachial artery by high resolution ultrasonography as a non-invasive measure of endothelial function by a randomized, double- blind, cross-over design. We also measured plasma levels of Hcy, malondialdehyde as an index of oxidative stress, and tetrahydrobiopterin, an essential co-factor of NO synthase and for which synthesis folic acid plays a crucial role, before and after interventions. One week of folic acid supplemetation increased plasma levels of folic acid by 5-fold of the basal level (from 7.2±0.7 to 32.4±2.2 ng/ml, p<.0001). Flow-mediated vasodilation was significantly increased to 2-fold of the baseline (from 6.9±0.4 to 13.5±0.8 %, p<.0001), whereas endothelium-independent vasodilation by nitroglycerin was not changed. The placebo had no effects on vascular function. Although plasma levels of malondialdehyde or tetrahydrobiopterin were not altered, folic acid supplementation significantly decreased plasma Hcy from normal pretreatment levels to subnormal levels (from 8.3±0.6 to 6.0±0.4 nmol/ml, p<.0005). Furthermore, there was an inverse correlation between plasma levels of Hcy and flow-mediated vasodilation (r=-.63, p=.0002). Thus, chronic supplementation of folic acid restored endothelial function in smokers via Hcy-dependent mechanisms. Our results suggest that plasma Hcy may be a modulator of endothelial dysfunction in subjects with coronary risk factors.
A Quantitative Trait Locus for Sodium-Lithium Countertransport Is Linked to Chromosome Four in Baboons
Authors: Kammerer Candace M , Cox Laura A , Mahaney Michael C , Rogers Jeffrey , Shade Robert E
Published: March 2022

P134

Alterations in cell sodium transport characteristics, such as red blood cell intracellular sodium (ICNa) levels and sodium-lithium countertransport (SLC), are secondary biochemical indices of a primary cell membrane abnormality that have been associated with some forms of essential hypertension. We are studying the effects of genes and environmental factors on hypertension and blood pressure-related phenotypes such as ICNa and SLC in baboons, a non-human primate model for blood pressure regulation. In a previous study of 84 baboons, systolic blood pressure increased with increasing ICNa (p = 0.002) and SLC (p = 0.06). In the current study, genotypes for 280 microsatellite loci, as well as SLC and ICNa data, were determined for 623 baboons comprising 11 pedigrees. The heritabilities of ICNa and SLC were 0.80±0.07 and 0.61±0.10, respectively. We performed a genome screen using a maximum-likelihood based, variance components linkage analysis program (SOLAR) and obtained evidence that a possible quantitative trait locus (QTL) for SLC is located on the baboon homologue of human chromosome 4 between D4S2456 and D4S2365 with a maximum multipoint lod-score = 8.76 (p< 10
-10
) at D4S1645. This QTL accounts for approximately 2/3 of the additive genetic variation in SLC in baboons. We found no evidence for linkage with ICNa. Thus, we have evidence that a gene located on human chromosome 4 (baboon chromosome 5) affects cell sodium transport in baboons. No strong candidate genes have yet been identified in this region. However, future studies to identify and characterize this gene may elucidate fundamental processes that contribute to the development of hypertension.
ACE I/D
Genotype Determines
in Vivo
Bradykinin Metabolism in Humans
Authors: Murphey Laine J , Gainer James V , Vaughan Douglas E , Brown Nancy J
Published: March 2022

P140

Bradykinin (BK)is a cardioprotective peptide that is inactivated by ACE. An insertion(
I
)/deletion(
D
) polymorphism in the
ACE
gene determines plasma ACE levels. The
D
allele is associated with increased cardiovascular morbidity and mortality. These correlations may be due to increased conversion of Ang I to Ang II or, alternativley, to increased degradation of BK to its inactive product BK1-5. We determined the effect of
ACE I/D
on
in vivo
BK metabolism. BK (400 ng/min) was infused into the brachial artery of volunteers homozygous for the
ACE I
or
D
allele. Forearm venous blood was analyzed for BK and BK1-5 using a sensitive and specific liquid chromatography-mass spectroscopy method. ACE activity, venous BK1-5 conentration and BK1-5:BK ratio were higher in
D/D
vs
I/I
subjects, while BK tended to be lower (Table). Total kinin concentration in venous blood correlated with net t-PA release across the forearm (r
2
=0.51, P=0.0012). The
ACE I/D
polymorphism determines the
in vivo
degradation of BK in humans. The ratio of BK1-5:BK may serve as a marker for tissue ACE activity.
Pyk2/Cakβ Negatively Regulates Angiotensin Ii-Induced Vascular Hypertrophy
Authors: Eguchi Satoru , Frank Gerald D , Motley Evangeline D , Sasaki Terukatsu
Published: March 2022

P159

PYK2/CAKβis a Ca
2+
-dependent tyrosine kinase which has been shown to activate Src tyrosine kinase and downstream mitogen-activated protein kinases (MAPKs) such as extracellular signal-regulated kinase (ERK), c-Jun amino-terminal kinase (JNK), and p38 MAPK depending on a cell-type. Although angiotensin II (Ang II)-induced activation of PYK2 has been implicated in vascular remodeling, the precise role of PYK2/CAKβin Ang II-induced MAPK family activation and cell growth in vascular smooth muscle cells (VSMCs) remain largely unclear. To resolve this question, cultured rat aortic VSMCs were transfected with adenoviral vector expressing either wild type rat PYK2/CAKβ(PykWT) or its dominant-negative K457A mutant (PykDN), and MAPK family activation and protein synthesis were compared. The activation of MAPKs was measured by immunoblotting with the phospho-specific antibodies that selectively recognize the activated MAPKs. Protein synthesis was determined by
3
H-leucine incorporation. Both PykWT and PykDN transfection had no effect on Ang II-induced ERK activation. By contrast, PykWT transfection inhibited Ang II-induced JNK and p38 MAPK activation, whereas PykDN transfection markedly enhanced their activation. Interestingly, Ang II-induced
3
H-leucine uptake was totally blocked by PykWT transfection. However, PykDN transfection had no effect on Ang II-induced
3
H-Leucine uptake. From these data, we conclude that PYK2/CAKβnegatively regulates Ang II-induced vascular hypertrophy possibly through its inhibitory effect on JNK and p38 MAPK, providing new insight into the signal transduction mechanism of vascular remodeling.
Eta Receptor Antagonist Prevents Blood Pressure Elevation and Vascular Hypertrophy of Resistance Arteries in Aldosterone-Infused Rats.
Authors: Park Jeong Bae , Schiffrin Ernesto L
Published: March 2022

P173

In salt-sensitive hypertension vascular endothelin-1 expression may be enhanced. Endothelin antagonism lowers blood pressure (BP), and reduces vascular hypertrophy. We therefore evaluated whether the selective ETA receptor antagonist BMS182874 (BMS) prevents BP elevation and vascular hypertrophy in resistance arteries of aldosterone-infused rats. Rats received subcutaneous aldosterone (0.75μg/h) and 1% sodium in drinking water ± BMS (40mg/kg in food) for 6 weeks. Systolic BP was monitored by tail cuff method, and vascular changes were evaluated using a pressurized myograph. Aldosterone-infusion significantly increased BP to 151±7mmHg compared to controls (108±4mmHg, p<0.01). BMS normalized BP (117±4mmHg, p<0.01). Aldosterone increased media width and media to lumen ratio (17.6±0.4μm and 7.5±0.4%) compared to controls (14.2±0.5μm, p<0.01 and 5.9±0.0%, p<0.05, respectively). BMS normalized media and media to lumen ratio (15.1±0.6μm and 5.7±0.1%, both p<0.01). Endothelial function assessed with acetylcholine (10
-6
M) did not differ in the 3 groups. Maximal endothelin-1 (10
-7
M)-induced vasoconstriction was similar (58-62%) in all groups. In conclusion, the ETA receptor antagonist attenuated blood pressure elevation and prevented vascular hypertrophy of resistance arteries in aldosterone-infused rats.
Arterial Pressure Increases in Dogs with Chronic Hyperinsulinemia if COX-2 Is Inhibited.
Authors: Brands Michael W , Hailman Allison E , Fitzgerald Sharyn M
Published: March 2022

P175

A series of studies has shown that chronic insulin and glucose infusion does not increase mean arterial pressure (MAP) in dogs, but we have shown that the same infusion protocol or infusion of the glucose alone increases arterial pressure in rats. Thromboxane (TX) and prostaglandin (PG) production increase during the infusion, and the pressor response in rats is TX-dependent. This study tested whether in dogs PG production prevents arterial pressure from increasing. Six dogs were instrumented and assigned in random crossover design to chronic cyclooxygenase-2 (COX-2) inhibition or vehicle. Following control measurements, hyperinsulinemia was induced in all dogs with a 6-day iv. infusion of 50% dextrose (950 ml or 475 g glucose/day), which raised plasma insulin from 14±3 to 45±5 μU/ml with no significant change in blood glucose during the infusion. MAP (measured 24 h/d) decreased in control dogs during glucose infusion as shown previously but increased significantly in the dogs with COX-2 inhibition (between-group difference ∼ 9 mm Hg). Heart rate increased similarly in both groups, as shown previously, and there were no between-group differences in sodium excretion. The acute depressor response to a 10 mg iv. bolus of arachidonic acid was blocked completely in dogs during COX-2 inhibition but there was no GI distress associated with chronic inhibitor treatment. This is the first study to report a chronic pressor response with hyperinsulinemia in dogs and it also suggests that the inability to detect this relationship previously was due to COX-2-mediated prostaglandin production.
A Low-Calorie Diet Improves Endothelium-Dependent Vasodilation in Obese Patients with Essential Hypertension
Authors: Sasaki Shota , Higashi Yukihito , Ozono Ryoji , Matsuura Hideo , Kajiyama Goro , Oshima Tetsuya
Published: March 2022

P179

Objective: This study investigated the effects of a low-calorie diet on endothelial function in obese patients with essential hypertension. Methods: We measured forearm blood flow during intraarterial infusion of acetylcholine (7.5, 15, 30 μg/min, an index of endothelium-dependent vasodilation) and isosorbide dinitrate (0.75, 1.5, 3.0 μg/min, an index of endothelium-independent vasodilation) in obese patients with essential hypertension before and after 2-weeks of the low-calorie diet (800 Kcal/d). The study included 11 obese hypertensive Japanese patients (mean body mass index: 30.8 ± 3.6 kg/m2). Fifteen healthy Japanese normotensive individuals were recruited as a control group. Results: In obese patients with hypertension, the response of forearm blood flow to acetylcholine was attenuated compared to healthy individuals (P<0.001). Caloric restriction reduced body weight from 77.5±15.0 to 73.2±13.5 kg (P<0.01), the mean blood pressure from 118.4±8.7 to 105.7±8.5 mm Hg (P<0.01), fasting plasma insulin from 85.8±22.8 to 64.8±27.0 pmol/L (P<0.05), serum total cholesterol from 5.30±0.76 to 4.67±0.58 mmol/L (P<0.05), and low density lipoprotein cholesterol from 3.80±0.48 to 3.29±0.44 mmol/L (P<0.05). Basal forearm blood flow was similar before and after weight loss. Caloric restriction enhanced the response of forearm blood flow to acetylcholine (P<0.05), but did not alter the response to isosorbide dinitrate. The intraarterial infusion of NG-monomethyl-L-arginine (8 μmol/min, a nitric oxide synthase inhibitor) decreased the enhanced acetylcholine-induced blood flow response induced by caloric restriction. Conclusion: The present findings suggest that weight loss with caloric restriction improves endothelial-dependent vasodilation through an increased release of nitric oxide in obese hypertensive patients.
Attenuated Angiotensin Ii-Response in Transgenic Mice Expressing the At1 Receptor in the Vascular Endothelial Cells.
Authors: Ramchandran Ramaswamy , Barrett-Stull Linda , Wilk Dennis , Vince Geoffery , Miura Shin-ichiro , Zhang Jingli , Boros John , Husain Ahsan , Moravec Christine , Karnik Sadashiva
Published: March 2022

P186

The angiotensin II AT1 receptor mediated vasoconstriction is believed to be due to direct stimulation of vascular smooth muscle cells by the hormone angiotensin II (AngII). Recent evidence suggests that AT1 receptors, also expressed on endothelial cells (EC), on stimulation couple to activation of Ca+2 calmodulin-dependent nitric oxide synthase and NO release i
n vitro
. These AT1 receptors may mediate a vasodilatory function in the endothelium
in vivo
, contributing to regulatory mechanisms in blood pressure control. To investigate the physiological role of AT1 receptors on ECs, we generated transgenic mice expressing a constitutively active AT1[N111G] receptor specifically in vascular ECs using the mouse
tie
gene promoter. Of the three tie-AT1 founder lines with varying copies of transgene, two (TG23 and TG26) showed EC-specific transgene RNA transcript, and receptor protein expression when stained with an epitope-specific antibody. Increased mortality complemented with lack of homozygosity was observed in heterozygous TG23 mice. Tail-cuff systolic blood pressures measured were significantly reduced in TG23 tie-AT1 mice (116±2 TG versus 142±2 control) suggesting a vasodilatory effect mediated by the transgenic receptor. Change in arterial pressure to infused AngII (1 μg/kg body wt.) measured was depressed by approx. 40 % in TG23 tie-AT1 mice compared to controls, and a lower dose (0.2 μg/kg body wt.) evoked no response. These results suggest that the AngII-mediated response
in vivo
seems to depend on the cell types of the vascular beds and their downstream signaling events which may have important regulatory functional consequences.
Attenuation of Hypertension and Heart Hypertrophy by Recombinant Adeno-Associated Virus Delivering Angiotensinogen Antisense (rAAV-AGT-AS)
Authors: Kimura Birgitta , Mohuczy Dagmara , Tang Xiaoping , Phillips M. Ian
Published: March 2022

P199

Introduction: We have previously shown that injection of antisense oligonucleotides (AS-ODNs) or plasmid producing antisense directed against angiotensinogen (AGT) mRNA, lowers BP in spontaneously hypertensive rats (SHR). The effects with ODNs, however, last ∼7 days. For more prolonged effects we have developed a recombinant adeno-associated viral vector (rAAV) to deliver AS-DNA targeted to AGT. Methods: Since captopril has been shown to inhibit development of hypertension in SHR, we hypothesized that AGT inhibition would prevent hypertension. Five day old SHR were injected with a single dose of 10
9
ipf (25 μl), intra-cardiacly, with AGT-AS-DNA (n=10) or control sense-AGT-DNA (n=6). Systolic BP was measured weekly from 6 and 26 weeks of age. At 14 weeks and 7 months, tissue DNA was analyzed for presence of the transgene. At 26 weeks, the left ventricle of the heart was dissected, weighed and compared to body weight, to determine the degree of hypertrophy (n=5/group). Every three weeks plasma was sampled for RIA of AGT. Results: The rats injected with rAAV-AGT-AS had lower BP than the control group from 10 weeks of age. The difference was significant at 10,11,12 and 13 weeks of age (p<0.05). The maximum difference was at 12 weeks (172 ± 7 for control versus 150 ± 8 mmHg for the treated group). Plasma AGT levels in the treated group did not correlate to BP, whereas plasma AGT in controls correlated to BP (p<0.05). The treated group had significantly lower BP than controls at 6 months (p<0.05). The presence of AS-transgene was confirmed by nested PCR on the DNA isolated from the heart, kidney and liver. The rAAV-AGT-AS significantly decreased the left ventricular hypertrophy measured at 26 weeks (LV/BW ratio: 3.18 ± 0.02 for control versus 2.92 ± 0.04 for the treated group, p<0.001). No signs of toxicity or body weight loss were observed. Conclusion: The study shows that AAV is a stable, effective vector to deliver AGT antisense and that AGT is an important factor in the development and maintenance of high BP in SHR. We conclude that the rAAV-AGT-AS vector shows promise for long-term attenuation of BP and heart hypertrophy.
Abstract 151: Counterintuitive Trends in Obesity Prevalence and Abnormal Blood Pressures Among Adults in NAMCS-NHAMCS Data
Authors: Chandrasekharan Gopal , Thomas Joshua R , Nair Madhuri , Zhao Yan D , Fox Mark D
Published: March 2022

BACKGROUND:
It has been suggested by national data and popular media that prevalence of obesity and elevated Blood Pressure (BP) has increased in the United States over time.

OBJECTIVE:
To assess the trends in the prevalence of elevated BP and obesity in adult patients, and to quantify any correlation between them using national probability data sets.

DESIGN/METHODS:
An analysis of visit data for all patients 18 years and older included in the 2005-09 National Ambulatory Medical Care Survey (NAMCS) and National Hospital Ambulatory Medical Care Survey-Outpatient Department (OPD) was performed. BP data from 160,380 patient visits were analyzed, including adults seen in ambulatory or office-based settings (NAMCS, N=74,645) and hospital outpatient departments (OPD, N=85,735). Correlation between BP and BMI were calculated using the Pearson Correlation method.

Results:
Overall, the prevalence of hypertension decreased over time, while the prevalence of obesity increased. This data is represented in Table 1.

Conclusions:
This analysis suggests that while the prevalence of obesity may be increasing, the prevalence of elevated BP has actually decreased over time. This seemingly counter-intuitive finding may reflect improved BP control rates, despite obesity, which is suggested in contemporary NHANES data.
Abstract 162: Increased Allele-Specific Expression of Angiotensinogen Derived From the -20C vs. -20A In Subcutaneous Adipose Tissue From Anonymous Human Donors
Authors: Park Sungmi , Chatterjee Tapan K , Rudich Steven M , Weintraub Neal L , Sigmund Curt D
Published: March 2022

The mechanism by which single nucleotide polymorphisms (SNP) regulate angiotensinogen (AGT) expression in humans has been extensively studied but remains unclear. The E box (
C
ACGTG) at position -20 in the human AGT promoter binds USF1 and USF2
in vitr
o. Recently, we published that USF1 and USF2 are both essential for human AGT expression in double transgenic mice carrying a -20C SNP in human AGT and a gene trap USF1 knockdown. Therefore, we hypothesize that selective binding of USF1/2 to -20C versus -20A (the rs5050 SNP) in the promoter region underlies the enhanced expression of AGT in humans containing the rs5050 SNP. We genotyped subcutaneous adipose tissue from 89 anonymous human donors for both the A-20C SNP and a coding region SNP known to be in linkage disequilibrium with the A-20C (C620T; rs4762). Based on sequencing and TOPO TA cloning, 22% of the samples were heterozygous for A-20C and linkage disequilibrium between -20A with 620C and -20C with 620T was confirmed in 80% of the samples. AGT and USF2 mRNA was elevated significantly (2.0±0.3 and 2.2±0.4 fold, n=8, respectively) in the male -20AC compared to the -20AA group, whereas expression of fatty acid synthase, a known USF target gene, was unchanged. These changes in expression were not observed in females, suggesting sexual dimorphism in the regulation of both USF1/2 and AGT. We developed and validated a quantitative PCR assay using Taqman probes selective for the mRNA separately corresponding to 620T and 620C. We used this assay on RNA derived from 16 heterozygous (-20AC and 620CT) subcutaneous adipose samples. Expression derived from the -20C promoter (620T mRNA) was 4.1±0.6 fold higher compared to the -20A promoter (620C mRNA) (n=16). We have also developed a quantitative allele-specific assay to measure USF1/2 binding to -20AC for use in ChIP. We conclude that USF1/2 and the -20C SNP play physiological roles in AGT regulation in human adipose tissue which we hypothesize is due to increased USF recruitment at -20C.
Abstract 169: Activation of The Interleukin-1 Receptor Contributes to the Pathogenesis of Angiotensin II-dependent Hypertension by Regulating Sodium Excretion
Authors: Zhang Jiandong , Patel Mehul B , Griffiths Robert , Sparks Matthew , Crowley Steven
Published: March 2022

Interleukin 1(IL-1) is an important regulator of inflammation and innate immunity and exerts diverse actions in multiple tissue beds. Previous studies have found increased renal IL-1 production in the setting of angiotensin (Ang) II-induced hypertension. The current study therefore explored whether activation of the IL-1 receptor (IL-1R) contributes to the pathogenesis of Ang II-dependent hypertension. Thus, we chronically infused uni-nephrectomized IL-1R-deficient (IL-1R KO) mice and wild-type (WT) controls (n=9 per group, 129/SvEv strain) with Ang II (1000ng/kg/min) for 4 weeks. At baseline, the mean arterial blood pressure (MAP) was similar in WT and IL-1R KO mice (131±9 vs. 125±6 mm Hg; p=NS). By contrast, after the 1st week of Ang II infusion, IL-1R KO mice had markedly attenuated elevations in BP (169±6 vs.184±3 mm Hg; p<0.05). Consistent with their lower BPs, IL-1R KO mice had smaller heart weight/body weight ratios compared to WTs after Ang II infusion for 14 days (7.4±0.2 vs. 6.7±0.3 mg/g, p=0.058) and 28 days (9.3±0.8 vs. 7.5±0.9 mg/g, p<0.001). Moreover, Ang II-infused IL-1R KOs had nearly 40% less albuminuria than WTs (5.9±0.9 vs. 9.4±1.4 mg/mg Cr; p=0.05). Consistent with reduced renal damage in the Ang II-infused IL-1R KOs, this group had lower renal mRNA expression of the kidney injury marker NGAL than Ang II-infused WTs (0.37±0.06 vs. 1.00±0.19 au; p=0.008) whereas expressions of IL-1α and β were similar in the 2 groups. Levels of urinary sodium excretion were similar in the groups at baseline and during the 1
st
week of Ang II when BPs were also similar. However, during the 2
nd
week of Ang II when BPs started to diverge between the groups, the IL-1R KOs excreted 23% more sodium than WT controls (416±23 vs. 337±25 μmol/day; p<0.04) while daily food intake was virtually identical in the groups throughout the experiment. As IL-1 has known vascular effects and renal blood flow can impact sodium excretion, we then examined acute pressor responses to Ang II (100ng) after 2 weeks of chronic Ang II infusion. The pressor response was blunted by 25% in IL-1R KOs compared to WT controls (30±2 vs. 41±4 mm Hg, p=0.04). We conclude that activation of the IL-1R potentiates Ang II-dependent hypertension by enhancing vasoconstriction and thereby limiting sodium excretion.
Abstract 176: Hypertension in a Rat Model of HELLP Syndrome is Associated with T Helper 1 Type Immune Activation
Authors: Wallace Kedra , Darby Marie , Kyle Patrick , Scott Jeremy , Moseley Janae , Brewer Justin , Owens Michelle Y , LaMarca Babbette
Published: March 2022

HELLP syndrome (hemolysis, elevated liver enzymes, low platelets) is a severe form of preeclampsia, which is a hypertensive disorder that occurs during pregnancy. While the symptoms and consequences of HELLP syndrome are often severe, the physiological mechanisms involved are still unknown. Previous studies demonstrate that simultaneously elevated sFlt-1 and sEndoglin, causes symptoms similar to HELLP syndrome in pregnant rats. In this study we utilized this HELLP syndrome rodent model to determine if an immunological cascade occurs similarly to that seen in HELLP patients. On gestational day (GD) 14 miniosmotic pumps infusing sEndoglin (7ug/kg/day) and sFlt-1 (3.7ug/kg/day) were implanted into normal pregnant (NP) rats. On GD18 carotid catheters were inserted and mean arterial pressure (MAP) was recorded on GD19. Plasma and tissue was also collected to determine adverse pathology and markers of inflammation. MAP increased from NP (n=7) 104+3 to 122+3mmHg in HELLP rats (n=14) (P=0.002). Alanine aminotransferase liver enzymes were also increased from 37.78+4.5 IU/L in NP to 62.85+6.1 IU/L in HELLP rats (P=0.007) and platelets were decreased in HELLP rats (6286+1209uL) compared to NP rats (28375+4547uL, P = 0.0007). TNF alpha and IL-6 were increased in HELLP rats (54.74+12.67pg/mL vs. 25.65+3.5pg/mL n=8; P = 0.04) and (103.6+26.5pg/mL vs. 40.18+ 8.2pg/mL/ P = 0.04) compared to NP rats. Furthermore, HELLP rats had increased CD4+ T lymphocytes compared to NP rats, circulating 14.37% vs. 9% gated; placental 8.67% vs. 5.99% gated; spleen 12.4% vs. 7.84% gated; liver 8.27% vs. 1.7% gated. In this study we demonstrate that hypertension in a newly adapted rat model of HELLP syndrome, is associated with a T helper 1 immune activation similar to that seen in HELLP patients.
Abstract 183: Hypertension Increases Toll-Like Receptor 2 (TLR2) and Inflammatory Cytokine Expression in the Corpus Cavernosum From Sprague Dawley Rats
Authors: Davis Jason , Nunes Kenia P , Stallmann-Jorgensen Inger , Clinton Webb R.
Published: March 2022

Erectile dysfunction (ED) significantly reduces quality of life and is an early warning of cardiovascular disease. The prevalence of ED is higher among hypertensive compared to normotensive men. Activation of the immune system has been implicated in the development of hypertension; however, the role of the immune system in the development of ED remains unknown. In this study, we hypothesized that TLR2, a key player in innate immunity, is increased leading to an inflammatory response in the corpus cavernosum of hypertensive rats. We induced hypertension in male Sprague Dawley (SD) rats (age 15-weeks) via administration of N (G)-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor, for 4 weeks in drinking water (500mg/L). Our results showed that the mean systolic blood pressure from L-NAME treated rats was significantly greater (p<0.05) compared to controls (208±33 vs 121±3mmHg). Western blot analysis demonstrated that protein expressions of TLR2, along with its primary intra-cellular signaling protein, myeloid differentiation primary response protein 88 (MyD88), were higher in the corpus cavernosum from L-NAME-treated rats compared to controls (1.691±0.2 vs 1.000±0.1) and (2.177±0.2 vs 1.000±0.3), respectively. Our results also showed that, there is an increase in the phosphorylation of the nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκBα) in the corpus cavernosum from L-NAME-treated rats compared to controls (2.038±0.2 vs 1.000±0.2). Additionally, the cavernosal tissue expression levels of the pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-α) was also increased in the L-NAME-treated group compared to control (2.757±0.4 vs 1.000±0.3). Together, these data suggest that increased activation of TLR2 may initiate an inflammatory response which may lead to corpus cavernosum dysfunction, potentially contributing to ED in a rat model of hypertension induced via nitric oxide synthase inhibition.
Abstract 185: Utilization of Nanoformulated Copper/Zinc Superoxide Dismutase (CuZnSOD) to Attenuate the Central Angiotensin II-Induced Pressor Response
Authors: Rosenbaugh Erin G , Tian Jun , Manickam Devika S , Kabanov Alexander V , Zimmerman Matthew C
Published: March 2022

Elevated levels of superoxide (O
2
.-
) in the brain and dysregulation of angiotensin II (AngII)-dependent neural mechanisms are associated with cardiovascular diseases, such as hypertension. For improved brain delivery of CuZnSOD protein, a O
2
.-
-specific scavenging enzyme, we developed SOD nano, a polyion complex with a polyethylene glycol corona and polyethyleneimine core that electrostatically binds CuZnSOD protein. Our previous studies in cultured neurons indicate that SOD nano enters neurons through active endocytosis and localizes to various organelles where it scavenges O
2
.-
and effectively inhibits AngII intra-neuronal signaling. Here, we hypothesized that centrally administered SOD nano ameliorates AngII-dependent neurogenic hypertension by delivering functional CuZnSOD protein to AngII sensitive brain regions. For these studies, C57Bl/6 male mice were instrumented with carotid catheter radiotelemeters to record mean arterial pressure (MAP). Intracerebroventricular (ICV) cannulae were implanted for the administration of SOD nano and daily injections of AngII (350 ng) before and after SOD nano treatment. The average AngII-induced increase in MAP for 3 days prior to treatment was 9.2 + 0.7 mmHg. ICV-administered SOD nano (113 U SOD activity) significantly inhibited the acute, central AngII pressor response for at least 3 days (ΔMAP D1= 1.3 + 1.4 mmHg; D2 = -2.7 + 3.7 mmHg; D3 = 3.4 + 4.1; n=3, p< 0.05 vs. AngII response 3 days prior). In contrast, ICV-administered saline did not alter the AngII-induced pressor response (ΔMAP D1 = 8.0 + 2.8 mmHg, D2 = 9.6 + 1.5, D3 = 7.3 + 1.2, n=4). Additionally, free CuZnSOD protein (ICV, 113 U SOD activity) did not attenuate the central AngII pressor response (ΔMAP D1 = 6.6 + 0.4 mmHg, D2 = 10.7 + 2.3, D3 = 16.3 + 8.4, n=2); thus, suggesting enhanced stability and/or cellular uptake of the SOD nano compared to free protein. Notably, the distribution of fluorescently labeled SOD nanozyme administered ICV was detected throughout the ventricular system, primarily in ependymal cells lining the brain ventricles and in the choroid plexus. These data suggest that this nanotechnology approach is effective in delivery CuZnSOD protein
in vivo
to AngII sensitive brain regions where it inhibits brain angiotensinergic signaling.
Abstract 213: Neuron-specific (Pro)renin Receptor Deletion Attenuates Neurogenic Hypertension and is Associated With Improvement of Autonomic Function
Authors: Li Wencheng , Peng Hua , Eisenberg Richard L , Ichihara Atsuhiro , Feng Yumei
Published: March 2022

Although (pro)renin receptor (PRR) is highly expressed in the brain, the physiological importance of brain PRR remains to be determined. We previously showed that PRR mRNA levels were up-regulated in the brain regions involved in blood pressure (BP) regulation including the subfornical organs (SFO), paraventricular nuclei (PVN), and rostral ventrolateral medulla (RVLM) in the DOCA-salt-induced hypertensive mice. To elucidate whether the increase of PRR expression contributes to the development of hypertension, we developed a neuron-specific PRR knockout mouse (Nefh-PRR) model by crossing PRR-floxed mice with mice that express Cre-recombinase with neurofilament-H (Nefh-Cre) promoter. Immunostaining showed that PRR expression was significantly reduced in cardiac regulatory brain regions including SFO (0.35± 0.15), PVN (0.34 ± 0.09), and RVLM (0.41 ± 0.1), where the Cre-recombinase was expressed, in Nefh-PRR compared to Nefh-cre mice (1 ± 0.1, 1 ± 0.19 and 1 ± 0.06). Nefh-PRR mice and Nefh-cre mice with wild type PRR gene (WT, n=8/group) were implanted with telemetric probes. BP (mmHg) and heart rate (HR, bpm) were recorded for baseline and following DOCA-salt treatment (50mg DOCA, 0.9%NaCl drinking solution, 21 days). Nefh-PRR mice exhibited normal baseline BP and HR. Following DOCA-salt treatment, BP was significantly lower in Nefh-PRR mice (108 ± 3) compared to WT mice (132 ± 6, P<0.05). The cardiac sympathetic tone (HR response to propranolol, ΔHR: -128±46vs. -180±45) and the vasomotor sympathetic tone (BP response to chlorisondamine, ΔBP: -46 ±17vs.-68± 12) were lower in Nefh-PRR than WT mice after DOCA-salt treatment. Moreover, HR response to methylatropine (ΔHR: 98±38 vs. 43±19) was greater in Nefh-PRR. In addition, DOCA-salt treatment increased plasma vasopressin (AVP) levels (33.6 ± 5.3 vs.3.0 ± 0.3pg/ml) in WT mice. PRR deletion significantly attenuated the increase in plasma AVP levels (19.0 ± 2.0pg/ml) induced by DOCA-salt. The data suggest PRR deletion prevents the development of DOCA-salt hypertension and is associated with reduction of plasma AVP levels and improvement of autonomic function. We conclude that brain PRR may be a novel therapeutic target for the treatment of hypertension.
Abstract 217: Angiotensin II Stimulates Renin Synthesis and Secretion in Mouse Collecting Duct M-1 Cells via a PKCα-mediated cAMP Stimulation Mechanism
Authors: Liu Liu , Lara Lucienne , Gonzalez Alexis , Bourgeois Camille , Seth Dale , Prieto Minolfa
Published: March 2022

Angiotensin (Ang) II stimulates renin synthesis and secretion in collecting duct (CD) cells; via the Ang II type 1 receptor (AT1R), an effect that is in contrast to the well-known inhibition that it exerts on juxtaglomerular apparatus (JGA) renin. However, the intracellular signaling mechanisms involved in the Ang II-mediated stimulation of renin synthesis and secretion by the principal cells of the CD have not been elucidated. We recently demonstrated that Ang II increases renin synthesis via protein kinase C (PKC) in primary cultured rat IMCD cells. Additionally, we found that Ang II increases intracellular cAMP levels in IMCD cells, suggesting that in CD cells, PKA/CREB might be the downstream target of cAMP. In the present study, we used a mouse cortical CD cell line (M-1) to determine the role of the cAMP/PKA/CREB pathway in the stimulation of the Ang II-mediated renin synthesis and secretion by the principal cells, and to examine the role of PKC in the stimulation of cAMP levels in this mechanism. In M-1 cells, Ang II (10-7 M) treatment increased renin mRNA and protein levels. Renin content measured in the cell culture media was augmented in Ang II-treated cells by 6 hrs (Ang II: 31±4 vs. 19±4 ng Ang I/hr/ml; p<0.05). Ang II increased cAMP levels by 1 min (148±32 pmol/mg protein) and reached a peak at 30 min (290±27 vs. 44±0 pmol/mg protein; p<0.05). The adenlyate cyclase activator, forskolin (10-10M) and the analogue of cAMP, dibutyryl-cAMP (100 uM) both significantly increased renin transcript. Augmentation of renin mRNA by Ang II was prevented by PKA inhibition with H89 or PKI, and it was followed by increased pCREB levels. Importantly, PKC inhibition either with calphostin C (10-7M) or a PKCα dominant negative prevented the augmentation of intracellular levels of cAMP, pCREB and renin mRNA in M-1 cells treated with Ang II. We show here for the first time that in mouse collecting duct cells, Ang II stimulates renin synthesis and secretion via a PKCα-mediated cAMP stimulation mechanism. The sum of these findings suggests that in collecting duct cells, Ang II stimulates rather than inhibits renin, observations that contrast with the effect of PKC activity on JGA renin.
Abstract 219: Acyloxy Nitroso Compounds Inhibit LIF Signaling in Endothelial Cells and Cardiac Myocytes: Evidence That STAT3 Signaling is Redox-Sensitive
Authors: Zgheib Carlos , Kurdi Mazen , Zouein Fouad , Zgheib Joe , King S. Bruce , Paolocci Nazareno , Booz George W
Published: March 2022

Nitroxyl donors have positive inotropic and lusitropic effects that may have therapeutic potential for treating heart failure, but their effects on other signaling pathways are not well studied. Previously we showed that leukemia inhibitory factor (LIF)-induced signaling is inhibited by oxidative stress, which targets JAK1 activation. In addition, we recently reported evidence for a cysteine-based redox switch in the JH1 catalytic domain of JAK 1 and 2. Since nitroxyl is thiophylic, we postulated that nitroxyl donors would inhibit LIF-induced JAK-STAT3 activation. Pretreatment of human microvascular endothelial cells (HMEC-1) or neonatal rat ventricular myocytes with the nitroxyl donors Angeli’s salt and the recently-described nitrosocyclohexyl acetate (NCA) inhibited LIF-induced STAT3 activation as indexed by Y705 phosphorylation. Pretreatment of HMEC-1 with NCA also blocked LIF-induced expression of the inflammation-related genes, ICAM-1 and CEBPD. The related acyloxy nitroso compound 1-nitrosocyclohexyl pivalate (NCP), which is not a nitroxyl donor, was equally effective in inhibiting STAT3 activation, suggesting that these compounds were acting as electrophiles on a thiolate residue. NCA had no effect on the catalytic activity of JAK1 and modestly affected JAK1-induced tyrosine phosphorylation of the LIF receptor. Thus, the JH1 redox switch is not a direct target of the acyloxy nitroso compound. However, pretreatment of recombinant human STAT3 with NCA or NCP reduced the labeling of free sulfhydryl residues with fluorescein-5-maleimide. In addition, we document by dimedone labeling that oxidation of STAT3 is associated with formation of sulfenic acid residues, a hallmark of redox-sensitive proteins. Altogether our evidence indicates that STAT3 has redox-sensitive cysteines that regulate its activation and are targeted by nitroxyl donors and related acyloxy nitroso compounds. These findings raise the possibility of new therapeutic strategies to target STAT3 signaling.