bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract P275: A Randomized Clinical Trial on Dietary Nitrate and Blood Pressure
Authors: Sundqvist Michaela L , Weitzberg Eddie , Lundberg Jon O
Published: June 2021

Background:
Elevated blood pressure (BP) is a major risk factor for cardiovascular disease and premature death worldwide. Hypertension (i.e. BP of ≥140/90 mmHg) is even considered the leading risk factor for global burden of disease. Dietary strategies preventing hypertension includes the Dietary Approaches to Stop Hypertension eating plan. A vegetarian diet and high vegetable intake has also shown beneficial effects on BP regulation.

In the last 10 years there is an emerging interest in the positive effects of dietary nitrate (NO3
-
). Inorganic nitrate is converted to nitric oxide (NO) in our body with vasodilatory effects. Vegetables alone contribute with 60-80% (60-80 of 100) of the total nitrate intake in humans and the highest concentrations of this anion are found in green leafy vegetables and beetroots. Several short term studies have shown that administration of nitrate salts or high nitrate vegetables (HNV) have BP lowering effects. A large scale randomized clinical trial is needed to explore long term effects on BP after daily intake of HNV.

Methods:
The
Di
etary
Ni
tric
O
xide (DINO) study is a single site, randomized clinical trial including subjects (n = 300) between 50-70y with SBP 130-159 mm Hg. A wash out period of 2 weeks is followed by randomization to one of three intervention groups: HNV containing 300 mg nitrate + placebo pill, low nitrate vegetables (LNV) + nitrate supplement (300mg potassium nitrate) or LNV + a placebo pill. All subjects will have a constant vegetable intake during 5 weeks of HNV or LNV provided weekly by the investigators, to consume together with their normal diet. After the wash out period and in the last week of the study 24h ambulatory BP, 24h urine collection, and blood- and saliva samples are taken. Lifestyle habits are also monitored during the study. The primary endpoint is systolic ambulatory BP with 85% (85 of 100) power to detect a difference of 2mm Hg between the groups.

Conclusion:
The DINO study is designed to investigate the potential contribution of inorganic nitrate to the BP lowering effect attributed to vegetables. In addition, the three armed design makes it possible to evaluate natural sources of nitrate compared to supplements.
Abstract P276: Tissue Primacy of Chymase as an Angiotensin II-forming Enzyme from Angiotensin-(1-12)
Authors: Ahmad Sarfaraz , Varagic Jasmina , Cheng Che P , Collawn James F , Dell’Italia Louis J , Ferrario Carlos M
Published: June 2021

Breaking the prevailing acceptance of ACE primacy as the Ang II-forming enzyme, we have demonstrated that cardiac Ang II production in human and rat heart tissues are primarily mediated by chymase. In this study, we compared the affinity of cardiac chymase to generate Ang II from Ang-(1-12) or Ang I in plasma membranes (PMs) isolated from the diseased left atria of humans and SHR left ventricle. PMs (50-100 μg) were exposed to increasing concentrations of either Ang-(1-12) or Ang I substrate (0-300 μM) for 30 min at 37
o
C in the presence of lisinopril (200 μM). The K
m
and V
max
of human cardiac chymase (Mean ± SE) were 29 ± 0.9
vs
87 ± 8.8 μM and 57 ± 1.4
vs
145 ± 3.7 μM/min/mg for Ang-(1-12) and Ang I substrates, respectively. Similarly, the K
m
and V
max
of rat cardiac chymase were 64 ± 6.3
vs
142 ± 17 μM and 13.2 ± 1.3
vs
1.9 ± 0.2 μM/min/mg for Ang-(1-12) and Ang I substrate, respectively. These data suggest that cardiac chymase has a higher affinity for Ang-(1-12) substrate compared to Ang I in both human and rat heart tissues. Further, our kinetic data show that the catalytic efficiency (ratio of V
max
/K
m
) of human and rat chymase were 1.2 and 15.4-fold higher for Ang-(1-12) substrate compared to Ang I. Overall, our findings suggest that Ang-(1-12), rather than Ang I, is the preferred substrate for chymase in the generation of Ang II by human and rat heart tissue.
Abstract P287: Endothelial Dysfunction in Small Resistance Arteries of Patients with Severe Obesity: Role of Arginase
Authors: Virdis Agostino , Duranti Emiliano , Nannipieri Monica , Anselmino Marco , Grazi Andrea , Taddei Stefano
Published: June 2021

Nitric oxide (NO) is produced by endothelial NO synthase (eNOS) using the aminoacid L-Arginine. Arginase (Arg) also uses L-Arginine as substrate, converting it in L-Ornitine and urea. An increased Arg activity causes a progressive L-Arginine depletion, which in turn determines a lower NO bioavailability. Studies in murine models of obesity identify Arg as a determinant of endothelial dysfunction. In this study, we evaluated whether Arg might play a role in determining the lower bioavailability of NO in small resistance arteries isolated from subcutaneous tissue of patients with severe obesity (Ob), split in age groups (younger than 30 aa, range 21-29, n=5; older than 30 aa, range 35-56, n=5) vs normoweight controls (Ctrl younger 30 years, range 20-29, n=5; older than 30 yrs, range 36-58, n=5). Each patient underwent a subcutaneous biopsy during a laparoscopic surgical procedure. Small arteries, isolated from periadvential fat, were evaluated on a pressurized micromyograph. Endothelium-dependent vasodilation (VD) was assessed by acetylcholine (Ach, 0,001-100μM). NO availability was assessed by repeating Ach with L-NAME (100μM). Ach was also infused in the presence of norNOHA (10μM, Arg inhibitor). In Ctrl, VD induced by Ach was inhibited by L-NAME and not modified by norNOHA. Ob younger exhibited a reduced VD induced by Ach vs Ctrl of the same age, a reduced inhibition by L-NAME, and a potentiating effect by norNOHA, which also normalized the inhibitory effect of L-NAME on Ach. In Ob older, VD induced by Ach was reduced vs Ob younger, resistant to L-NAME and not modified by norNOHA.

In conclusions, in small arteries from younger Ob, the Arg inhibition improves endothelial function by increasing the NO availability, while in older Ob Arg does not seem to play any role in endothelial dysfunction.
Abstract P305: Sympathetic Activation Elicited by Bilateral Carotid Occlusion Attenuates Cytokine Release in Conscious Endotoxemic Rats
Authors: Brognara Fernanda , Castania Jaci A , Dias Daniel P , Fazan Rubens , Cunha Fernando Q , Patel Kaushik P , Ulloa Luis , Kanashiro Alexandre , Salgado Helio C
Published: June 2021

Our previous studies suggest that carotid occlusion can induce a sympathetic signal able to modulate the immune system. Here, we analyze whether bilateral carotid occlusion (BCO) affect the innate immune response to bacterial lipopolysaccharide (LPS) in endotoxic rats. In order to prevent the neuronal alterations induced by anesthesia, we performed our studies of BCO in conscious rats. Wistar rats were implanted with pneumatic cuffs around the common carotid arteries for BCO. Femoral and peritoneal catheters were also inserted for blood pressure recording and LPS administration. Rats were randomly assigned to the following groups: Saline, LPS + SHAM (LPS in the presence of the occluders but without occlusion) and LPS + BCO (LPS combined with bilateral carotid occlusion). BCO was performed for 20s in conscious awake rats, right before LPS (5.0 mg/kg) or saline (control) administration. Plasma and spleen samples were collected at 90 min after LPS or saline administration. As compared to baseline arterial pressure, BCO produced a peak response in mean arterial pressure of 52 ± 3 mmHg, confirming the sympathetic activation. BCO significantly attenuated TNF-α and IL-1β plasma levels as compared to those in SHAM endotoxemic rats [TNF: 1319 ± 388 (n = 6) vs. 583 ± 138 pg/mL (n = 8),
P
= 0.03; IL-1β: 2203 ± 256 (n = 5) vs. 1086 ± 157 pg/mL (n = 9),
P
< 0.001]. BCO also significantly reduced the TNF-α levels in the spleen [5.1 ± 1.3 (n = 7) vs. 1.7 ± 0.4 pg/mg tissue (n = 8),
P
= 0.005]. By contrast, BCO did not significantly change IL-6 and IL-10 levels in plasma [IL-6: 5609 ± 352 (n = 7) vs. 5879 ± 375 pg/mL (n = 10),
P
= 0.703; IL-10: 2417 ± 354 (n = 5) vs. 2068 ± 298 pg/mL (n = 9),
P
= 0.408] or in the spleen [IL-6: 15 ± 3 (n = 7) vs. 14 ± 2 pg/mg tissue (n = 10)
P
= 0.776; IL-10: 1.6 ± 0.2 (n = 7) vs. 1.3 ± 0.2 pg/mg tissue (n = 9),
P
= 0.475]. Moreover, the IL-1β level in the spleen was not affected by BCO [54 ± 12 (n = 6) vs. 28 ± 5 pg/mg tissue (n = 9),
P
= 0.058]. These findings indicate that sympathetic activation by BCO in conscious rats attenuates the pro-inflammatory cytokines release in the endotoxemic model induced by LPS without affecting anti-inflammatory cytokine IL-10.
Abstract P315: Vascular AT1 Angiotensin Receptors Do Not Contribute to Albuminuria or Hyperfiltration in Diabetes
Authors: Sparks Matthew A , Johnson Stacy , Adhikari Rishav , Diaz Edward , Kupin Aaron , Bendt Kat , Gurley Susan , Coffman Thomas
Published: June 2021

Blockade of the renin angiotensin system (RAS) reduces albuminuria, attenuates hyperfiltration, and slows the progression of diabetic nephropathy (DN) by preventing vasoconstriction and subsequent increases in glomerular hydrostatic pressure. Since RAS blockade disrupts Ang II signaling in all tissues, the specific contribution of vascular actions of AT1 receptors in DN has been difficult to delineate. Therefore, we generated 129 SvEv mice with cell-specific loss of AT1A from VSMCs (SMKOs) using
Cre-loxp
. To eliminate AT1R from VSMCs, we crossed the SMKO mice with AT1BR -/- mice, lacking the minor AT1B isoform. To study the impact of vascular AT1R in DN, we crossed the AT1B-
null
SMKOs with mice having the
Ins2
C96Y
AKITA mutation, which develop DM1 early. To enhance kidney injury, mice underwent uninephrectomy (UNX) at 11wks. Blood glucose levels were elevated (~500mg/dL) and similar at 10, 16 and 24wks between the two groups. Prior to UNX, albuminuria was similar between Control AKITA and AT1B-
null
SMKO AKITA (62±10 Control AKITA versus 107±27 μg/24hrs SMKO AKITA, P=NS). Albuminuria increased with age in both Control Akita and AT1B-
null
SMKO AKITA but without significant differences between the groups at 16wks (307±106 vs 313±117 μg/24hrs; P=NS) or 24wks (494±236 versus 730±217 μg/24hrs; P=NS), despite a trend toward higher albuminuria in AT1B-
null
SMKO AKITAs. There was no significant difference in GFR (using FITC-inulin) between non-diabetic Control and AT1B-
null
SMKO (15.6±1.2 vs 14.8±0.8 μl/min/g BW), and hyperfiltration was observed in both Control AKITA (23.7±2.4 μl/min/g BW; P=0.003) and AT1B-
null
SMKO AKITA mice (20.7±1.7 μl/min/g BW; P=0.01) relative to their non-diabetic comparators. However, there was no significant difference in GFR between ControlAKITA and AT1B-
null
SMKO AKITA (P=NS). Finally we measured mRNA levels of putative kidney injury markers by RTqPCR and found no differences in levels of
Col1A1
,
NGAL
, or
TGFB1
mRNA between Control AKITA and AT1B
null
SMKO AKITA. Our studies indicate that the absence of vascular AT1R responses is not sufficient to reduce albuminuria and prevent hyperfiltration in a mouse model of DN. This suggests that blockade of AT1R in other cell lineages may contribute to beneficial actions of ARBs in DN.
Abstract P324: Reduction in Excreted Sodium Load in Obese Sheep: Role of Antenatal Betamethasone and Sex
Authors: Bi Jianli , Su Yixin , Chappell Mark , Rose James
Published: June 2021

Our previous studies have demonstrated the programmed impairment of sodium excretion in lean antenatal betamethasone exposed sheep whereby the males exhibited blunted excretion of a sodium load when compared to control males or control or antenatal betamethasone exposed females. Obesity has been recognized as a risk factor for developing early stage kidney failure in individuals exposed to unfavorable intrauterine conditions by virtue of fetal programming. We hypothesize that obesity (second hit) can accentuate the impairment of sodium excretion in antenatal betamethasone exposed offspring in a sex specific manner.

Pregnant ewes received either betamethasone or vehicle at 80-81 days gestation. The male (n=6 per group) or female (n=5 per group) offspring were overfed to become obese (40% weight gain over a course of 3 months) at age of 1.5 years. Acute sodium load (sodium chloride: 0.13g/kg) was administrated intravenously. Sodium excretion (excreted sodium load), blood pressure (BP), renal plasma flow (RPF), and glomerular filtration rate (GFR) were measured. Data for sodium excretion are expressed as percentage of excreted sodium load. ANOVA and Student’s t test were used for data analysis.

The excreted sodium load was lower in obese male antenatal betamethasone exposed offspring (OMB) than in obese male vehicle exposed offspring (OMV) (13.5±3.1% vs. 33.2±9.9% p=0.04). However, the excreted sodium load was not significantly different between obese female antenatal betamethasone exposed offspring (OFB) and obese female vehicle exposed offspring (OFV) (60.4±6.2% vs. 72.0±8.2%, p=0.31). Compared male offspring with female offspring, the excreted sodium load was lower in male offspring (33.2±9.9% vs. 72.0±8.2%, p=0.001, OMV vs. OFV; 13.5±3.2% vs. 60.4±6.2%, p<0.0001, OMB vs. OFB). During the experiments BP, RPF and GFR did not change significantly. .

These data suggest that obesity, acting as a second hit, accentuates impairment of sodium excretion in antenatal betamethasone exposed male but not female offspring. Thus the sex specific effect of antenatal betamethasone on sodium excretion persists in in animals experiencing a secondary insult of obesity in adulthood.
Abstract P331: Renal Medullary Infusion of BAF312, a Sphingosine-1-phosphate Receptor-1 Agonist, Attenuates Angiotensin II-induced Hypertension
Authors: Zhu Qing , Hu Junping , Li Pin-Lan , Li Ningjun
Published: June 2021

Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid metabolite formed by phosphorylation of sphingosine and participates in the regulation of cardiovascular functions. We have recently shown that S1P increases sodium excretion in the renal medulla possibly through inhibiting epithelial sodium channel via the S1P receptor 1 (S1P1), which is mainly localized in collecting ducts with a higher expression level in the renal medulla than the cortex. The present study tested the hypothesis that infusion of an agonist to activate S1P1 in the renal medulla attenuates angiotensin (ANG) II-induced hypertension. Treatment of the mice with a high salt diet (HS, 4% NaCl) for 2 week significantly increased the levels of S1P1 in the renal medulla compared with that in low salt (LS) control by Western blot analysis, whereas this HS-induced increase in S1P1 level was blocked in mice treated with ANG II (600ng/kg/min, sc) (relative S1P1 levels: 1.0±0.19, 1.9±0.14 and 0.9 ±0.18 in LS, HS and HS+ANG II-treated mice, respectively). Infusion of a subpressor dose of ANG II (300ng/kg/min, sc) increased the mean arterial pressure (MAP) in mice with collecting duct-specific knockout of S1P1, but not in S1P1 floxed control mice (MAP: 132±4.7 vs. 96±1.1 mmHg). In contrast, infusion of BAF312, a selective agonist of S1P1, into the renal medulla attenuated the hypertension induced by a pressor dose of ANG II (600 ng/kg/min, sc) in uninephrectomized mice (MAP: 102±1.8, 161 ±7.1 and 133±3.9 in vehicle, ANG II and ANG II+BAF312-treated mice, respectively). These data suggest that inhibition of S1P1 level in the renal medulla may contribute to the pathogenesis of ANG II-induced hypertension and that stimulating the S1P1 pathway may be used as a therapeutic strategy for the treatment of hypertension.
Abstract P334: Sympathetically Mediated Alpha-1 Adrenoceptor Regulation of the NCC During High Salt Intake: A New Therapeutic Target for Resistant Hypertension
Authors: Wainford Richard D , Walsh Kathryn R
Published: June 2021

Aim:
We hypothesize that excess norepinephrine (NE) modulates NCC activity via an α1 adrenoceptor pathway to drive the development of salt-sensitive hypertension (HTN).

Methods:
Male Sprague-Dawley (SD) rats receiving a continuous s.c. saline or NE (600ng/min) infusion and naïve Dahl Salt-Sensitive (DSS) rats were fed a 0.6% (NS) or 8% NaCl (HS) diet for 14 or 21 days respectively (N=4/gp). On day 14 (SD) or 21 (DSS) MAP and NCC activity (peak natriuresis to iv hydrochlorothiazide (HCTZ; 2mg/kg) infusion) and expression (via immunoblotting) was assessed. Additional groups of NE infused SD and DSS rats received a propranolol (9.9mg/kg/day; s.c.) or prazosin (2.5mg/kg/day; oral) and a NS or HS diet for 14 or 21 days.

Results:
SD rats exhibit HS evoked suppression of NCC expression and activity. In contrast, NE infused SD rats and DSS rats exhibit HTN and fail to suppress NCC expression and activity during HS-intake. β-adrenoceptor antagonism (confirmed pharmacologically) reduced MAP in NE infused SD and DSS rats, but failed to decrease NCC activity or expression. In contrast α1-adreoceptor antagonism (confirmed pharmacologically) abolished the salt-sensitive component of HTN and restored dietary sodium evoked suppression of NCC activity and expression in NE infused SD rats and DSS rats.

Conclusion:
Our data suggests NE activates α, but not β, adrenoceptors to prevent dietary sodium evoked suppression of NCC activity and the development of salt-sensitive hypertension. The PATHWAY-2 Trial reported a primary role of sodium retention in resistant HTN suggesting α1-adreoceptor antagonism represents a new therapeutic approach for resistant and sympathetically mediated HTN.
Abstract P338: Heme Oxygenase Induction Suppresses Hepatic Hepcidin and Rescues Ferroportin and Ferritin Expression in Obese Mice
Authors: Chaudhry Hibba , Nichols Alexandra , Sodhi Komal , Srikanthan Krithika , Nawab Athar
Published: June 2021

Hepcidin, a phase II reactant secreted by hepatocytes, regulates cellular iron levels by increasing internalization of ferroportin- a transmembrane protein facilitating egress of cellular iron. Chronic low-grade inflammatory states, such as obesity, have been shown to increase oxidative stress and enhance hepcidin secretion from hepatocytes and macrophages. Heme-heme oxygenase (HO) is a stress response system, the induction of which reduces oxidative stress thereby abating patho-physiological conditions such as obesity and metabolic syndrome.8 week old male obese (ob) mice and their age- and sex-matched lean mice were used as controls. CoPP was administered intraperitoneally once a week (3 mg/kg) for 6 weeks to obese mice. CoPP plus stannous mesoporphyrin (SnMP) was administered intraperitoneally three times a week (20 mg/kg) for 6 weeks.

We investigated the effects of HO-1 induction on hepatic hepcidin levels and on iron homeostasis in tissues from lean and obese mice. Obese mice exhibited hyperglycemia along with increased levels of pro-inflammatory cytokines (MCP-1, IL-6, p<0.05), oxidative stress and increased hepatic hepcidin levels (p<0.05). Enhancement of hepcidin was reflected in the reduced expression of ferroportin in obese mice (p<0.05). Further, our results showed attenuation of insulin receptor phosphorylation and attenuation of metabolic regulators including pAMPK, pAKT and pLKB1. Cobalt protoporphyrin (CoPP)-induced HO-1 up-regulation in obese mice and reversed these pathophysiological alterations (p<0.05) while attenuating hepatic hepcidin levels and enhancing ferritin expression. These effects of CoPP were prevented in obese mice concurrently exposed to an inhibitor of HO (SnMP) (p<0.05).

Taken together, our results highlight a modulatory effect of HO on iron homeostasis mediated through the suppression of hepatic hepcidin in conjunction with the rescue of cellular ferritin levels. Therefore, these findings may prove an effective strategy in treating the metabolic consequences of obesity including alteration of liver iron homeostasis.
Abstract P342: Vascular Protein Oxidation and Redox Proteomics in Hypertension
Authors: Tsiropoulou Sofia , Montezano Augusto C , Scott Alan , Burchmore Richard J , Touyz Rhian M
Published: June 2021

In hypertension (HTN) mechanisms whereby protein oxidation regulates vascular function remain unclear. We hypothesise that increased ROS promote a shift of oxidative post-translational protein modifications from reversible to irreversible forms, leading to aberrant redox signalling and vascular injury. VSMC from mesenteric arteries of normotensive (WKY) and hypertensive (SHRSP) rats were stimulated with Ang II (10
-7
M) in the presence/absence of PEG-catalase (1000U/ml) or tempol (10
-5
M). Protein carbonylation was assessed by oxyblot and protein sulfenylation by DCP-Rho1 fluorescent probe. Protein tyrosine phosphatase (PTP)-oxidation, peroxiredoxin hyperoxidation (PRXSO3), γH2AX, Bcl2 levels were assessed by immunoblotting. DiGE and CyDye labelling screened for reversibly oxidised thiol proteome. Irreversible carbonylation and PRXSO3 were increased in SHRSP (fold change (FC)=1.29 and 2.77, p<0.05). Ang II-stimulation did not alter carbonylation levels. Reversible sulfenylation and thiol-proteome oxidation were reduced in SHRSP (FC=-1.18, p<0.05 and 13.6% (253 spots)). Ang II-treatment increased sulfenylation in WKY (FC=1.08, p<0.05) and SHRSP (FC=1.23, p<0.001); an effect inhibited by catalase. Reversible PTP oxidation was increased in WKY and SHRSP (FC=1.92 and 2.42, p<0.05), versus irreversible levels. Irreversible PTP oxidation tended to be higher in SHRSP. Ang II increased reversible PTP oxidation only in WKY (FC=1.27, p<0.05) and it was prevented by tempol. Ang II-stimulation increased protein levels of γH2AX (DNA damage) (FC=1.76, p<0.05) and Bcl2 (anti-apoptotic) (FC=2, p<0.05) in WKY. Proteomic data, filtered for FC>2, detected 1777 spots with 21% being differentially oxidised between WKY and SHRSP. Candidate proteins differentially oxidized between WKY and SHRSP include annexin A1 (-2.29) and galectin-1 (2.83). These results demonstrate altered redox status in HTN characterised by increased protein hyperoxidation and decreased reversible oxidation, in combination with decreased anti-oxidant capacity. Moreover, our findings identify novel candidate oxidized proteins implicated in VSMC motility, proliferation and signalling which may contribute to oxidative vascular injury in HTN.
Abstract P344: Increased Expression and Function of Endothelin Receptors in Aorta of (mRen2)27 Hypertensive Rats
Authors: Pulgar Victor M , Ademoyero Oludamilola T , Sidach Serguei S , Aileru Azeez A
Published: June 2021

Endothelin-1 (ET-1) contributes to various cardiovascular diseases including hypertension. ET-1 is produced in the endothelium and acts via ET
A
receptors, located in smooth muscle cells, and via ET
B
receptors, located in both endothelium and smooth muscle cells. Activation of ET
A
produces vasoconstriction, whereas endothelial ET
B
activation mediates vasodilation, with previous studies showing that ET-1-mediated vasoconstriction is enhanced in hypertension. We hypothesized that increased ETA-mediated function is present in vasculature of the (mRen2)27 hypertensive rat. Western blotting of total protein extracts from thoracic aorta was used to determine expression of ET
A
and ET
B
from Sprague-Dawley (SD n=4) and (mRen2)27 hypertensive (n=5) rats. Specificity of western blot signals for ET
A
and ET
B
was assessed by using pre-absorption of primary antibody with the corresponding antigenic peptide and intensity of signals was measured by densitometry (NIH-J Image). Contractile responses to ET-1 (10
-11
-10
-7
M) in intact and denuded aorta were determined by wire myography (Multi Myograph, DMT-USA) in the presence of the ET
A
blocker BQ123 (10
-6
M) or the ET
B
blocker BQ788 (10
-6
M). Contraction to ET-1 was expressed as maximal response (ET
MAX
as %K
MAX
) and sensitivity (pD
2
=-Log [EC
50
]). In aortae from (mRen2)27 rats ET
A
and ET
B
receptor expression (48 and 31 kDa bands) was greater relative to aortae of SD rats (p<0.05). ET-1 contraction showed increased sensitivity in (mRen2)27 vs SD aortae (pD
2
, 8.17±0.15 vs 7.76±0.12, p<0.05) with similar ET
MAX
(157±16 vs 145±6 %K
MAX
, p>0.05). In intact arteries, blockade of ET
B
increased ET-1 sensitivity (pD
2
8.4±0.3, p<0.05) in SD without effect on intact arteries from (mRen2)27 rats. In denuded arteries, ETB blockade increased ET
MAX
only in aortae from (mRen2)27 (205±12 vs 152±5, p<0.05). Thus, increased ET
A
expression mediates greater ET-1-dependent contraction in vasculature of (mRen2)27 rats. In (mRen2)27 rats, loss of endothelial ET
B
receptor function in intact arteries may contribute to enhanced constrictor responses to ET-1, whereas increased ET
B
receptors in smooth muscle cells provide a counterbalancing vasodilation to offset maximal contractile effects of ET-1 in this model of hypertension.
Abstract P345: Plasma Insulin Like Growth Factor Binding Protein-7 and Tissue Inhibitor of Metalloproteinase-2 are Associated with Reduced Renal Blood Flow and Change in Kidney Function After Revascularization in Human Atherosclerotic Renovascular Disease RVD
Authors: Saad Ahmed , Herrmann Sandra , Tang Hui , Woollard John , McKusick Michael , Lerman Lilach , Textor Stephen
Published: June 2021

Background:
Insulin-like growth factor binding protein7 (IGFBP-7) and tissue inhibitor of metalloproteinase-2 (TIMP-2) reflect G1-cell cycle arrest and are used as biomarkers for AKI. Recent studies show that these biomarkers rise in ischemic conditions and suggest that they actually may limit the severity of AKI. We tested the hypothesis that renal vein [IGFBP-7]*[TIMP-2] correlate with reductions in renal blood flow (RBF) and post-stent single kidney (SK)-GFR changes in patients with RVD undergoing contrast-based imaging and stent revascularization

Methods:
Inpatient studies were performed during 150 mEq Na+ intake and ACE/ARB Rx in patients with hemodynamically severe RVD (n=29, Doppler velocity = 318 ± 100cm/sec, and eGFR= 34.7 ± 11.7 mL/ min) scheduled for renal artery stenting, and compared to essential hypertensive (EH) healthy controls (n=32). Cortical and medullary RBFs (by multidetector CT) and renal vein levels of IGFBP-7 and TIMP-2 were measured before renal artery stenting and 3 months later

Results:
Pre-stenting IGFBP-7 and TIMP-2 levels were elevated in RVD compared to EH (18.5±2. vs 15.7±1.5 and 97.4±23.1vs 62.7±9.2 ng/mL respectively,
P
<0.0001). Baseline renal vein levels of IGFBP-7 * TIMP-2 correlated inversely with pre-stent RBF (r= - 0.53, P=0.01) and directly with the change (%) in SK-GFR observed 3 months after stenting

Conclusion:
IGFBP-7 and TIMP-2 levels are elevated in patients with chronic RVD as a function of the baseline reduction in RBF, and associate with subsequent improvement in SK-GFR 3 months after revascularization. These data are consistent with renovascular occlusion inducing cell-cycle arrest that serves to protect kidney function.
Abstract P606: Cortisol Levels Correlate with Emotional Response to Perceived Racism in African American Males But Not Females
Authors: Pointer Mildred A , Yancey Sadiqa , Wells Candace , Sanchez Jesus A , McClelland Marilyn
Published: June 2021

Hypertensive African American (AA) males have as much as a 14-fold greater risk for kidney disease compared to others with hypertension. The reason for this greater risk is unknown. We have previously reported that stress contributes to resting blood pressure in normotensive AAs and can exacerbate the renal injury associated with hypertension in animal models. Consequently, we hypothesize that environmental stress activates the stress hormone system to a greater degree in AA males compared to females either due to either greater environmental stress (ES) exposure and/or greater stress hormone response to perceived ES. In this study we measured the level of perceived racism (PR), emotional response to PR (E), and baseline salivary cortisol (C) in normotensive AA males (n=39) and females (n=86). AA males had significantly higher PR scores compared to AA females for each of three domains: job (29 ± 3 vs 21 ± 2; p=0.005); academic (27 ± 3 vs 20 ± 2; p<0.05); and public (35 ± 3 vs 28 ± 2; p<0.05). Although E and C did not differ between males and females (55 ± 3 vs 58 ± 2 and 0.2 ± 0.03 vs 0.2 ± 0.03, μg/dL, respectively), E was significantly correlated with C in males (p=0.033) only. There was no difference in age (25 ± 1 vs 23 ± 1, years) between the two sexes but systolic blood pressure was significantly higher in the males (121 ± 1 vs 114 ± 2, mmHg). We interpret these results to mean that ES is more likely to activate the stress system of AA males than that of AA females. Thus, in a culture where AA may experience greater unfair treatment in the job, academic, and public domains, activation of the stress hormone system in AA males may explain the disparity of kidney disease. The reason(s) for this sex difference in stress hormone response to perceived ES is intriguing and warrants further investigation.
Abstract P610: Hypertension Is Associated With Profound Pathological Changes In The Gut
Authors: Qi YanFei , Mandloi Avinash S , Santisteban Monica M , Shenoy Vinayak , Cole-Jeffrey Colleen T , Lobaton Gilberto O , Stewart Daniel , Rubiano Andres , Simmons Chelsey , Katovich Michael J , Pepine Carl J , Raizada Mohan K
Published: June 2021

Background and objective:
Our previous studies have shown that gut microbial dysbiosis is linked to hypertension (HTN) in both animal models and patients with high blood pressure (BP) (
Hypertension
2015; 65:1331-40
). The intestinal epithelial layer serves as a barrier against pathogens and is altered in paracellular permeability with bowel diseases. Accordingly, our objective in the present study was to test the hypothesis that HTN-linked gut dysbiosis is associated with changes in gut wall pathophysiology.

Methods and Results:
Two rat models of were used: pre-hypertensive juvenile SHR (MAP 97 ± 5 mmHg) and adult SHR (MAP 160 ± 3 mmHg) with corresponding control WKY rats and chronic Angiotensin II (Ang II) infusion rat model of HTN (saline MAP 95 ± 2 mmHg vs. Ang II 150 ± 3 mmHg). A fluorescein isothiocyanate conjugated (FITC) dextran feeding protocol and a custom indentation system were used for permeability and stiffness assessments, respectively. Segments of small intestine were used for histology. We observed no significant differences in gut permeability and stiffness in pre-hypertensive juvenile SHR vs WKY controls. However, a 2-fold difference in gut permeability was observed in adult SHR (SHR 3514±563.4 vs WKY 1777±427.8, RFU, p<0.05). In addition, a 10-fold difference in gut wall stiffness (effective modulus) in adult SHR was observed (SHR 53.3±32.2 vs WKY 5.3±1.6, kPA, p<0.05). Histology revealed that adult SHR had 20% stunted villi length (SHR 580±54 vs WKY 718±6, μm, p<0.05) and a 60% increase in fibrotic area (SHR 13.8±1.3 vs WKY 8.5±0.8, p<0.05). Similar differences in gut permeability, elastic modulus, villi length and fibrotic area were observed in the Ang II HTN rat model. In contrast, pre-hypertensive, juvenile SHR did not show these differences.

Conclusions:
These observations, for the first time, demonstrate that increased BP is associated with profound gut pathology. They suggest that gut wall integrity likely plays a critical role in regulation of BP hemostasis and host microbiota communications with blood vessels.
Abstract P614: Relationship Of Sodium Intake And Stress With Bone Health In Women
Authors: Jasti Allison , Stewart Deborah L , Harshfield Gregory A
Published: June 2021

Background:
The skeleton is vital to sodium homeostasis, accounting for 40% of the body’s sodium. Research indicates stress and low sodium intake are independently associated with RAAS activation. In certain populations, stress can induce salt sensitivity, increasing the risk of hypertension and target organ damage, but the association of low versus high sodium intake with bone health is controversial.

Purpose:
This study sought out the relationship of low sodium and stress-induced RAAS activation with bone health. The tested hypothesis was those with lowest sodium intake would have lower total bone mineral density (TBMD) and content (TBMC) associated with stress-induced increases in angiotensin ii (Ang II) and aldosterone (Aldo).

Methods:
We compared effect of stress on Ang II, Aldo, TBMD and TMBC in healthy Caucasian and African-American adolescents. Subjects were grouped by quartiles based on sodium intake, assessed by urinary sodium excretion.

Results:
Due to females, overall significant inverse associations are observed between TBMD, TBMC, Ang II and Aldo in the lowest sodium intake quartile. Post-stress, women in the lowest sodium intake quartile showed that increases in both Ang II and Aldo correspond with lower TMBC and TMBD. There was no significance between Ang II, Aldo, TMBC and TMBD in the three highest quartiles of women nor in any male quartile.

Conclusion:
These data suggest Ang II and Aldo may reduce TMBC and TMBD in women. Stress-induced increases in Ang II and Aldo, with low sodium intake, may further reduce TBMD and TBMC in women. Ang II inhibition and/or moderated salt intake may be an efficacious prevention or treatment against the development of osteoporosis.
Abstract P622: Characterization of 125-I-Angiotensin (1-7) Binding to Rat Kidney
Authors: Conti Filipe F , Linares Andrea , Couling Leena E , Morris Mariana , De Angelis Katia , Speth Robert C
Published: June 2021

Despite the plethora of data indicating beneficial effects of angiotensin (1-7) (Ang 1-7) on the cardiovascular system, its putative receptor, Mas, has not been characterized in tissue membrane preparations other than single concentration demonstrations of the localization of
125
I-Ang 1-7 binding sites in rat kidney. This does not indicate the specificity of
125
I-Ang 1-7 binding nor does it indicate the actual densities of the binding sites, i.e., B
max
(fmoles/mg tissue), or dissociation constant (K
D
) to indicate binding affinity of
125
I-Ang 1-7 for its putative receptor. To characterize
125
I-Ang 1-7 binding in the kidney we prepared a low specific activity, monoradioiodinated Ang 1-7 using a 1:19 mix of
125
iodine :
127
iodine which allows for assessment of the B
max
and K
D
with concentrations of radioligand up to 100 nM. Frozen kidneys from adult male albino rats were dissected and homogenized in water and the membranes were precipitated by centrifugation at 48 kxG. Membranes were resuspended in Tris:MgCl
2
(50:1) pH 7.2 and incubated with 12 concentrations of
125/127
I-Ang 1-7 ranging from ~3-100 nM for 30 min at 22 C, after which bound
125/127
I-Ang 1-7 was resolved from unbound
125/127
I-Ang 1-7 by filtration and measured with a gamma counter. Specific binding (defined as 100 μM Ang 1-7 displaceable binding) of
125/127
I-Ang 1-7 showed a moderate binding affinity (K
D
= 14.7 ± 1.8 nM) and binding site density (B
max
= 24.5 ± 9.9 fmoles/mg initial wet weight). The B
max
value tended to be lower than that in the liver (B
max
= 62.3 ± 20.1 fmoles/mg initial wet weight) and the K
D
value was significantly greater (lower affinity) than that in the liver ( K
D
= 5.7 ± 0.6 nM, p = 0.0085). Of note, competition for
125/127
I-Ang 1-7 binding Ang 1-7 indicated that the IC
50
for Ang 1-7 competition for
125/127
I-Ang 1-7 binding was 42.5 μM. Moreover, the ability of a variety of angiotensin peptides to inhibit
125/127
I-Ang 1-7 binding at 100 μM, Ang 1-7 was less potent that the other angiotensin peptides: Ang III > Ang II > Ang I ~ Ang IV > Ang 2-7 > Ang 1-7 ~ Ang 3-7. These studies suggest that the binding site for
125/127
I-Ang 1-7 is not specific for the putative Ang 1-7 receptor mas, and may represent a low affinity binding to the AT
1
or AT
2
receptor
Abstract P623: Endothelial Dysfunction and Abnormal Perivascular Adipose Tissue Signaling in Subcutaneous Vessels from HIV-infected individuals
Authors: Wang Dan , Wang Cheng , Wang Cuiwei , Liu Chenglong , Verbesey Jennifer , Tomlinson James , Leiper James , Kassaye Seble , Young Mary , Wilcox Christopher S
Published: June 2021

Objective:
Perivascular adipose tissue (PVAT) normally promotes vascular endothelial function, whereas is impaired by reactive oxygen species (ROS) in CVD. But PVAT effects on microvessels in HIV are unexplored. We previously reported endothelial dysfunction in living subcutaneous microvascular arterioles (SMAs) dissected from a gluteal biopsy in HIV infected individuals. We test hypothesis that HIV increases microvascular ROS and asymmetric dimethylarginine (ADMA) leading to impair microvascular function and PVAT signaling.

Methods:
Isolated SMAs with or without PVAT were prepared from young African American HIV-infected (n=8) and matched HIV-uninfected women (n=6) enrolled in the DC Women’s Interagency HIV Study (DC-WIHS). HIV-infected participants were virally suppressed on HAART without identified CVD risk factors (except obesity). SMA’s acetylcholine (ACh)-induced endothelium dependent relaxation (EDR), nitric oxide (NO) activity (DAF-FM), ACh-induced endothelium dependent contractions (EDC) and ROS generation (temp-9AC), plasma L-arginine, ADMA and adipose adipokines and malondialdehyde (MDA) were measured.

Results:
HIV-infected participants had significantly (
p
<0.05) reduced plasma ratio of L-arginine : ADMA (99 ± 13 vs 182 ± 32 μmol/μmol), increased adipose MDA (15.1 ± 2.5 vs 10.9 ± 2.6 ng/mg protein) and leptin (40 ± 9 vs 28 ± 7 ng/mg protein); and reduced adiponectin in plasma (14 ± 2 vs 23 ± 2 ng/ml) and in adipose (2.1 ± 0.3 vs 4.6 ± 1.3 ng/mg protein). ACh-induced EDR (57 ± 4 vs 71± 4%) and NO (0.20 ± 0.03 vs 0.58 ± 0.07 Δfluoresce unit) were significantly attenuated
(p<0.05)
in vessels from HIV-infected participants, whereas EDC (22 ± 2 vs 7 ± 2%) and O
2
-
(0.17 ± 0.02 vs 0.09 ± 0.02 Δfluoresce unit) were significantly increased

(
p
<0.05)

. PVAT significantly increased

(
p
<0.05)

EDR (87 ± 3 vs 72 ± 4%) and NO (0.84 ± 0.09 vs 0.58 ± 0.08 Δfluoresce unit) only in control vessels.

Conclusion:
HIV-infected individuals have reductions in NO synthase substrate: inhibitor ratio (L-arginine:ADMA) and consequent increased intrinsic vascular effects of ROS leading to disruption of the beneficial microvascular PVAT signaling pathway. Therapeutic targets for vascular dysfunction in HIV should include ROS and its extravascular actions on ADMA and PVAT.
Abstract P624: Prevalence, Predictors and Comparison of Spironolactone versus Clonidine as a Fourth Drug for Resistant Hypertension: the Resistant Hypertension Optimal Treatment (ReHOT) study
Authors: Krieger Eduardo M , Drager Luciano F , Giorgi Dante M , Pereira Alexandre C , Barreto-Filho José A , Nogueira Armando R , Mill José G , Krieger José E
Published: June 2021

Background:
The prevalence, predictors and the best anti-hypertensive regimen for resistant hypertension (RH) are not well established especially in Countries with multiethnic profile. Our main aim was to compare spironolactone versus clonidine as a fourth drug therapy for patients with RH.

Methods:
This is a multicentric, randomized controlled trial comprising 26 sites in Brazil that recruited outpatients from a highly admixed population with hypertension stage 2 (≥160/100mmHg) at study entry. Medical therapy adherence was checked by pill counting. Patients with confirmed RH (no office and 24hs ambulatory blood pressure monitoring - ABPM - control despite treatment with 3 drugs including a diuretic for 12 weeks) were randomized to additional 12 weeks treatment with spironolactone (12.5-50mg once daily) or clonidine (0.1-0.3mg twice daily). The primary endpoint was blood pressure (BP) control from both office (<140/90mmHg) and 24hs ABPM (<130/80mmHg). Secondary endpoints included absolute and relative BP reductions in each study arm.

Results:
A total of 1597 patients were included in the analysis. We found that 14.9% (238 patients) fulfilled the RH criteria. Predictors of true RH include male gender (OR 1.43; CI 1.02-2.00), previous stroke (OR 2.81; CI 1.51-5.06), diabetes (OR 2.09; CI 1.48-2.94) and BP ≥180x110mmHg at study entry (OR 2.53; CI 1.88-3.43). Compared to patients randomized to spironolactone (n=119), those patients randomized to clonidine (n=119) presented similar rate of the primary endpoint (19.8 vs. 24%, respectively; p=0.59). Similarly, no differences were observed between groups in the blood pressure reduction analyzed either by office as well as by 24-h ABPM. No differences in the pill counting monitoring were observed in the groups.

Conclusions:
Appropriate treatment for stage 2 hypertension under the national universal health care conditions provided blood pressure control in 85% from a highly admixed population. Spironolactone or clonidine displayed comparable BP control as a fourth drug in patients with RH.

Funding:
Ministry of Health/H. Samaritano, National Research Council, Sao Paulo Research Foundation and Zerbini Foundation.
Abstract P627: Improved Autonomic Cardiovascular Regulation and Reduced Symptoms Associated with Use of Closed-loop Noninvasive Neurotechnology by Healthcare Workers
Authors: Tegeler Catherine L , Shaltout Hossam A , Howard Lindsay I , Tegeler Charles H
Published: June 2021

Introduction:
Chronic stress in healthcare workers is associated with insomnia and risk for adverse health outcomes. High-resolution, relational, resonance-based, electroencephalic mirroring (HIRREM) is a noninvasive, closed-loop acoustic stimulation neurotechnology that identifies dominant brain frequencies and translates them into audible tones, to support auto-calibration and self-optimization of brain rhythms.

Objective:
We explore use of HIRREM in a cohort of healthcare workers enrolled in an IRB-approved open label feasibility study of HIRREM for diverse neuropsychological disorders.

Methods:
Twenty five employees (16 female), mean (SD) age 45.8 (13.9), received 14.8 (4.7) HIRREM sessions (90-120 minutes each) over 9.0 (3.6) days of in-office intervention. Data was collected before (V1), and 15.4 (11.7) days after completion (V2). Outcomes included BP and HR recordings for autonomic cardiovascular regulation (baroreflex sensitivity, BRS, and heart rate variability, HRV), with inventories for insomnia (ISI), depression (CES-D), traumatic stress (PCL-C), quality of life (EQ-5D global rating), and drop stick reaction testing (RXT). Paired t-tests were performed.

Results:
BRS and HRV (n=17) improved from V1 to V2, including Sequence ALL (+2.4 ms/mmHg (SE 2.8), p=0.15), SDNN (+8.9 ms (4.1), p=0.04), and rMSSD ms (+9.2 (4.9), p=0.07). There were significant improvements in symptoms and function at V2; ISI (n=25): -8 (5.3), p<0.0001; CES-D (n=20): -7.3 (13.4), p=0.02; PCL-C (n=19): -12.1 (12.4); p<0.001; EQ-5D (n=16): +10.8 (12.5), p<0.01; RXT (n=18): -4.6 cm (5.5), p<0.01. There were no serious adverse events.

Conclusions:
This exploratory study shows improved measures of cardiovascular regulation, and reduced insomnia, depression, and stress associated with use of HIRREM in a cohort of employees at an academic medical center. Data suggest that HIRREM is a promising intervention that merits further investigation to mitigate effects of chronic stress and improve wellness.
Abstract P637: Absence Of Estrogen Receptor Alpha In T Regulatory Cells Results In Decreased Cardiac Glucose Uptake And Improves Diastolic Function In Western Diet-fed Female Mice
Authors: Manrique Camila , Lastra Guido , Aroor Annayya R , Chen Dongqing , Jia Guanghong , Ma Lixin , McKarns Susan C , Sowers James R
Published: June 2021

Diabetic women are at greater risk of developing cardiovascular disease than diabetic men. Our group has shown that insulin resistant female mice are more prone to develop diastolic dysfunction than male mice when fed a high fat/high fructose (western diet - WD). T regulatory cells (Tregs) suppress inflammation and insulin resistance, and estrogen receptor alpha (ERα) signaling has been postulated to modulate their function. Consequently, using a novel rodent model lacking ERα in Treg cells (TregERαKO) we tested the hypothesis that in conditions of WD-feeding, abrogation of ERα signaling in Tregs in female mice results in worsened whole-body and cardiac-specific insulin sensitivity, as well as diastolic function. Female TregERαKO mice and ERαFloxed (ERα
Fl2
) littermate controls were fed a WD for 16 weeks. WD consisted of high fat (46%) and high carbohydrate as sucrose (17.5%) and high fructose corn syrup (17.5%). At the end of the intervention, rodents underwent hyperinsulinemic-euglycemic clamps (n=7-9 per group) and, in a separate cohort, cardiac MRI (n=4 per group). Although TregERα deletion did not significantly impact whole-body insulin sensitivity (glucose infusion rate at steady state: 20 ± 2 vs. 17 ± 2 mg/Kg/min, TregERαKO vs. ERαFl
2
respectively, p=0.22), cardiac glucose uptake was significantly lower in the TregERαKO cohort (214.0±7.5 vs.167.3±19.6 μmol/min/100g tissue, TregERαKO and ERαFl
2
respectively p<0.05) indicating cardiac insulin resistance. MRI analysis revealed no differences in systolic function between the cohorts. The initial filling rate (a marker of diastolic function) was greater in the WD-fed TregERαKO cohort (0.29±0.08 vs. 0.53±0.09 μL/ms, TregERαKO vs. ERαFl
2
respectively, p<0.05) pointing toward enhanced diastolic function.

Conclusions:
In female mice fed a WD, lack of ERα signaling in Tregs results in cardiac-specific insulin resistance. However, the decreased cardiac glucose uptake did not translate into deterioration of diastolic function. Further studies are needed to evaluate the differential effects of TregERα deletion on glucose uptake and diastolic function.

Acknowledgments:
We acknowledge Vanderbilt MMPC for performing the clamps. MMPC is supported in part by grant U24 DK059637.
Abstract P642: Two Pools of Eicosatrienoic Acids in Humans: Alterations in Salt Sensitive Normotensive Subjects
Authors: Elijovich Fernando , Milne Ginger L , Brown Nancy J , Laniado-Schwartzman Michal , Laffer Cheryl L
Published: June 2021

We measured eicosatrienoic acids in 21 normotensive subjects classified as salt-resistant (SR=13) or salt-sensitive (SS=8) with the rapid protocol of Indiana University (high salt, HS=460 mEq Na/24 hrs, low-salt, LS=10 mEq Na/24 hrs + furosemide 40 mg x 3). No EETs were detected in urine; hence, ELISA 14-15 DHETs were taken to represent the total pool of this urine isoform (U-TP). Plasma total pools (8-9,11-12,14-15 and 14-15 P-TP) are the sum of EETs+DHETs (HPLC-MS), and their results were similar, so the former are reported. Analyses required log-transformation of not normally distributed data. U-TP was not changed by HS but decreased with LS (Δlog -0.47±0.19, p<0.01), consistent with the response of a natriuretic system. Further, in the baseline, HS and LS periods combined, U-TP correlated positively with UNaV (r=0.35, p<0.005), fractional excretion of Na (r=0.37, p<0.003) and Na/K ratio (r=0.39, p<0.002), indicating inhibition of ENaC. P-TP was not changed by HS (due to inhibited soluble epoxide hydrolase with reduction in DHETs and increase in EETs) but was increased by LS (Δlog 0.05±0.02, p<0.01), including EETs (0.04±0.02, p<0.03), inconsistent with a natriuretic system. P-TP did not correlate with urine parameters. Instead, plasma DHETs correlated with aldosterone (r=0.34, p<0.005) and plasma EETs with catecholamines (r=0.45, p<0.001). Differences between SR and SS subjects included: a) lower levels of U-TP and P-TP in SS than SR, significant in some stages of the experiment, b) lack of response of U-TP to changes in salt balance in SS, c) lack of the correlations between U-TP and natriuresis/ENaC activity and between DHET/aldosterone in SS, all observed only in SR. We conclude that: 1. Urine eicosatrienoic acids reflect a renal pool involved in regulation of natriuresis whereas plasma ones are probably of systemic origin and uninvolved in Na excretion, 2. There may be a feed-forward mechanism for the systemic, non-renal effects of aldosterone, by stimulation of inactive DHETs, 3. Catecholamines may stimulate epoxygenases or EETs may produce neuronal release of catecholamines, which remains to be investigated, and 4. Differences between SS and SR suggest abnormalities of eicosatrienoic acid regulation of natriuresis in SS subjects.