bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 082: Chronic Angiotensin-(1-7) Attenuates the Development of Obesity in Mice by Enhancing Energy Expenditure
Authors: Arnold Amy C , Finney Charlene , Biaggioni Italo
Published: June 2021

Activation of the renin-angiotensin system, and in particular angiotensin (Ang) II, is observed in obese patients and closely correlates with insulin resistance. Obesity is also associated with deficiency of Ang-(1-7), a vasodilatory peptide that mitigates Ang II actions. Accumulating evidence suggests that Ang-(1-7) has direct positive metabolic effects including reducing adiposity and reversing whole-body glucose intolerance and insulin resistance in animal models of cardiometabolic syndrome. In this study, we tested the hypothesis that chronic Ang-(1-7) administration would prevent high fat diet-induced obesity in mice, and determined potential mechanisms underlying this effect. To test this hypothesis, adult male C57BL/6J mice received a 12-week systemic infusion of Ang-(1-7) (400 ng/kg/min; n=7) or saline (n=6) via subcutaneous osmotic mini-pumps. Immediately following mini-pump implantation, mice were placed on a 60% high fat diet, with body mass measured weekly. Body composition (mq10 nuclear magnetic resonance analyzer), food and water intake, and energy expenditure (indirect calorimetry) were measured during the last week of treatment. Ang-(1-7) attenuated high fat diet-induced weight gain [39.7±1.3 Ang-(1-7) vs. 43.9±0.7 g saline at 12 weeks; p=0.023) and adiposity [32±1 Ang-(1-7) vs. 29±1% saline; p=0.050). The reduced gain in body weight following Ang-(1-7) was associated with increased average energy expenditure [0.55±0.02 Ang-(1-7) vs. 0.42±0.06 kcal/hour saline, p=0.038] and oxygen consumption [1.84±0.07 Ang-(1-7) vs. 1.39±0.23 ml/min saline, p=0.049] during the dark cycle, with no effect on locomotor activity. A similar trend for Ang-(1-7) to increase energy expenditure and oxygen consumption was observed during the light cycle. There were no significant differences in food or water intake following chronic Ang-(1-7) versus saline infusion. These findings suggest that targeting of Ang-(1-7) may be a novel strategy to prevent the development of obesity by enhancing energy expenditure, and further highlight the importance of the renin-angiotensin system in metabolic regulation.
Abstract 092: Novel Mechanism of Salt-sensitive Hypertension: CD8
+
T Cells Stimulate Sodium Chloride Co-transporter NCC in Kidney
Authors: Mu Shengyu , Liu Yunmeng , Rhee Sung , Webber Jessica , He Beixiang , Rafferty Tonya
Published: June 2021

Recent studies suggest a role for T lymphocytes in hypertension. However, whether T cells contribute to renal sodium retention is an important question, which if answered, could reveal a critical relationship between adaptive immunity and pathogenesis of salt-sensitive hypertension. In the present study, we propose a novel mechanism of salt-sensitive hypertension via the distal nephron: that in salt-sensitive hypertension, renal infiltrating T cells interact with distal convoluted tubule cells (mDCTs), which leads to up-regulation of the sodium-chloride-co-transporter (NCC), and thus enhancement of sodium retention. In vivo tests used DOCA-salt mice (SBP~190mmHg on a high salt diet) and T cell-adoptive transferred mice (SBP~170mmHg on a high salt diet). Results confirmed enhanced NCC & p-NCC expression (>2.5X) in the kidneys of both mouse models. We found significantly more T cells infiltrating the kidneys of DOCA-salt & T cell-transferred mice compared to their controls. It is noteworthy that in both models a great number of CD8
+
T cells (CD8Ts) in the renal tubulointerstitium surround DCT segments which have higher levels of NCC expression. Direct contact between these two cell types was confirmed by super-resolution structured illumination microscopy. In vitro, we co-cultured mDCTs with T cells, and found that CD8Ts, but not CD4Ts, significantly increased NCC expression (>3X) in mDCTs via “direct cell-cell contact”. An intracellular sodium-indicator detected higher NCC-mediated sodium uptake (>1.5X) in mDCTs treated with CD8Ts compared to untreated controls. Moreover, these effects were mediated by increased (>2.2X) functional chloride channel Clc-k in the cell membrane. Clc-k knockdown by siRNA blunted chloride efflux and abolished CD8T-induced NCC activation and sodium retention in mDCTs. Taken together, our findings suggest a novel role for CD8
+
T cells in enhancement of salt retention contributing to salt-sensitive hypertension: that CD8
+
T cells directly contact mDCTs, stimulate NCC by upregulating the chloride channel Clc-k on the mDCT plasma membrane, thereby increasing chloride efflux, which leads to compensatory chloride influx via NCC activation at the cost of increasing sodium influx.
Abstract 095: Ovariectomy Restores Purinergic Receptor Activation of Endothelin-dependent Natriuresis
Authors: Gohar Eman Y , Pollock David M
Published: June 2021

We have recently reported interplay between renal medullary endothelin-1 (ET-1) and purinergic (P2) systems, which play central roles in controlling Na
+
homeostasis in male rats. Evidence suggests that sex hormones regulate ET-1 and P2 systems. To test whether activation of the renal medullary P2 receptors promotes ET-dependent natriuresis in females and whether ovariectomy (OVX) modulates this potential interaction, we studied the effect of medullary NaCl loading on Na
+
excretion in adult intact female and OVX SD rats in the presence and absence of P2 or ET receptor antagonism. Isosmotic saline (284 mOsmol/kg H
2
O) was infused into the renal medullary interstitium during a baseline urine collection period, followed by isosmotic or hyperosmotic saline (1800 mOsmol/kg H
2
O) infusion. Blood pressure, renal blood flow, urine Na
+
, K
+
and osmolality were measured. Medullary NaCl loading significantly enhanced Na
+
excretion in intact females and OVX (from 0.8±0.2 to 6.2±1.6 and from 0.7±0.1 to 5.6±0.8 μmol/min, respectively, n=6-8, p<0.05). The natriuretic effect of NaCl loading in intact females was not attenuated by P2 or ET receptor blockade. Whereas, intramedullary infusion of the P2 receptor antagonist, suramin, inhibited the natriuresis induced by medullary NaCl loading in OVX (from 0.4±0.2 to 0.9±0.4 μmol/min, n=6). Additionally, combined ET
A/B
receptor blockade (ABT-627 + A-192621) abolished the natriuretic response to medullary NaCl load in OVX rats (from 0.2±0.1 to 1.4±0.7 μmol/min, n=4). Activation of medullary purinergic (P2Y
2/4
) receptors by UTP infusion had no significant effect in intact females, but enhanced Na
+
excretion in OVX rats (from 0.5±0.1 to 2.3±0.8 μmol/min, n=5, p<0.05). Combined ET
A/B
receptor blockade significantly inhibited the natriuretic response to UTP observed in OVX rats. These data suggest that increased medullary NaCl loading induces ET-independent and P2-independent natriuresis in intact females. In OVX, activation of medullary P2 receptors promotes ET-dependent natriuresis, similar to our previous findings in male rats and suggests that OVX restores the interplay between the renal ET-1 and purinergic (P2) signaling systems to facilitate Na
+
excretion. Funded by AHA 15POST25090329 to EYG and P01 HL95499 to DMP
Abstract 096: Leptin and High Salt Diet Induce Greater Increases in Blood Pressure in Female than Male Mice
Authors: Faulkner Jessica L , Belin de Chantemele Eric J
Published: June 2021

Recent studies by our group demonstrated that leptin is a direct regulator of aldosterone secretion and increases blood pressure via sex-specific mechanisms involving leptin-mediated activation of the aldosterone-mineralocorticoid receptor signaling pathway in females and sympatho-activation in males. Although it is well accepted that females secrete more leptin and aldosterone than males, it is unknown whether leptin infusion raises blood pressure similarly in male and female mice and whether higher aldosterone levels sensitize females to salt-induced hypertension. We hypothesized that female mice would be more sensitive to leptin than males and also have a potentiated blood pressure rise in response to high salt diet compared to males. Male and female Balb/C mice were implanted with radiotelemeters for continuous measurement of mean arterial pressure (MAP) at 10 weeks of age. MAP was measured for seven days prior to feeding with a high-salt diet (HS, 4%NaCl) for seven days. Following a recovery period, animals were then implanted with osmotic minipumps containing leptin (0.9mg/kg/day) recorded for seven days. Baseline MAP was similar between males and females (101.3±2.9 vs 99.3±3.7 mmHg, n=4 and 5, respectively), however, HS diet resulted in a greater MAP increase in females (15.0±2.6 mmHg) compared to males (3.1±4.5 mmHg, P<0.05). MAP with leptin treatment was increased with leptin in females moreso than in males, however, this did not reach significance (6.8±5.8 vs 1.8±5.9 mmHg, respectively). This potential sex difference in blood pressure responses to leptin was not associated with changes in body weight (0.07±0.44 vs -0.22±0.2 g, respectively) nor changes in blood glucose (-19.67±15.06 vs -15.4±11.4 mg/dl, respectively) in males and females in response to leptin. In summary, female mice are more sensitive to HS diet-induced blood pressure increases than males. Females may be more sensitive to leptin-mediated blood pressure increases than males. Further investigation is needed to determine whether these sex differences in blood pressure responses to HS diet and leptin are mediated by aldosterone or other mechanisms.
Abstract 112: The 20-HETE Receptor: a New Player in Hypertension
Authors: Garcia Victor , Gilani Ankit , Shkolnik Brian , Falck John R , Pandey Varun , Capdevila Jorge H , Schwartzman Michal L
Published: June 2021

Here, we report that GPR75, a G protein-coupled receptor of the Gq rhodopsin subfamily, selectively binds 20-hydroxyeicosatetraenoic acid (20-HETE), a cytochrome P450-derived bioactive arachidonic acid metabolite implicated in the pathogenesis of hypertension and cardiovascular diseases. In endothelial cells, 20-HETE binding to GPR75 stimulates β-arrestin recruitment and GIT1-GPR75 association, which further facilitates a c-Src-mediated transactivation of EGFR. This results in downstream signaling pathways which induce ACE expression and decrease NO bioavailability. Knockdown of GPR75 prevents 20-HETE-mediated downstream effects in endothelial cells including EGFR activation and ACE induction. In vascular smooth muscle cells, GPR75-20-HETE pairing is associated with Gα
q/11
-and GIT1-mediated PKC-stimulated phosphorylation of MaxiKβ, linking GPR75 activation to 20-HETE-mediated vasoconstriction. We used the conditional Cyp4a12tg mice, which display doxycycline (DOX)-mediated hypertension along with vascular dysfunction and remodeling in a 20-HETE-dependent manner, to assess whether GPR75 is a necessary component of 20-HETE pro-hypertensive actions. Administration of GPR75-targeted shRNA lentiviral particles to DOX-treated Cyp4a12tg mice, which resulted in 80% knockdown of GPR75 knockdown, prevented blood pressure elevation (100±3 vs 135±2 mmHg) and 20-HETE-mediated increases in ACE expression, endothelial dysfunction, smooth muscle contractility and vascular remodeling when compared to DOX-treated Cyp4a12tg mice receiving non-targeted shRNA. The discovery of 20-HETE-GPR75 pairing provides the molecular basis for the signaling and pathophysiological bioactions mediated by 20-HETE in hypertension. These results clearly place GPR75 as a novel target in the control of blood pressure and vascular function.
Abstract 118: Nebivolol Therapy Enhances Endothelial Fibrinolytic Capacity in Adults with Elevated Blood Pressure
Authors: DeSouza Christopher A , Bammert Tyler D , Diehl Kyle J , Dow Caitlin A , Greiner Jared J , Stauffer Brian L
Published: June 2021

Impaired endothelial fibrinolytic function contributes to increased thrombotic risk with elevated blood pressure
.
In vitro
data suggests that the antihypertensive, nebivolol (N), favorably effects the fibrinolytic system, but there is no
in vivo
clinical evidence that N treatment improves endothelial fibrinolytic function. We hypothesized that chronic N therapy will increase the capacity of the endothelium to release tissue-type plasminogen activator (t-PA) in adults with elevated blood pressure (BP ≥ 130/85 mm Hg). In an ongoing study, 36 middle-aged adults (age: 44-67 years) were treated for 12 weeks: 12 with N (5 mg/d; BP 141/86±2/2 mmHg); 12 with metoprolol succinate (M: 100 mg/d; 140/90±3/2 mmHg); and 12 with placebo (P; 138/85±2/2 mmHg). Before and after intervention, net endothelial release of t-PA was determined,
in vivo
, in response to intrabrachial infusions of bradykinin (BK: 125-500 ng/min) and sodium nitroprusside (SNP: 2-8 μg/min). Subject characteristics (age, BMI, systolic and diastolic BP) were similar between the groups. Blood pressure was lowered (P< 0.05) to a similar extent by both N (124/78±3/2 mmHg) and M (124/78±3/1 mmHg) but unchanged by P (134/80±3/2 mmHg). Endothelial t-PA release in response to BK was not significantly different between the N (-2.8±1.4 to 49.2±5.6 ng/100 mL tissue/min), M (-0.5±1.3 to 53.5±8.5 ng/100 mL tissue/min) and P (0.1±1.1 to 52.0±5.6 ng/100 mL tissue/min) groups prior to intervention. After intervention, only N therapy affected t-PA release; the capacity of the endothelium to release t-PA in the N group was significantly higher (-1.9±1.6 to 72.6±7.1 ng/100 mL tissue/min; P< 0.05). Total amount of t-PA released (area under the BK curve) markedly increased (45%) in response to N (308±39 vs 445±47 ng/100 mL tissue; P< 0.05). In contrast, endothelial t-PA release was not significantly altered by M (-1.6±1.1 to 54.0±6.1 ng/100 mL tisuue/min). As expected, t-PA release was unchanged with P. These results demonstrate that, in spite of similar reductions in blood pressure, N, but not M, treatment increases the capacity of the endothelium to release t-PA in adults with elevated blood pressure. Enhanced endothelial fibrinolytic function with N may provide an important vascular benefit in this at risk population.
Abstract 120: Reversal of Hypertension Stops, but Does Not Reverse, Renal T-cell Infiltration in the Dahl Salt-sensitive Rat
Authors: Evans Louise C , Petrova Galina , Kurth Theresa , Mattson David L , Cowley Allen W
Published: June 2021

In previous chronic servo control experiments we showed that increased renal perfusion pressure (RPP) amplifies renal T-cell infiltration in Dahl salt-sensitive (SS) rats. Renal T-cell infiltration was significantly higher in the right-hypertensive kidneys vs. the left servo-controlled kidneys of SS rats fed high salt (HS) for 7-days. There was no significant difference in T-cell infiltration in sham rats (both kidneys exposed to comparable RPPs). Here we use the chronic servo control system to determine whether the reversal of salt-sensitive hypertension reverses renal T-cell infiltration in SS rats.

An aortic balloon occluder was placed around the aorta, between the renal arteries to electronically servo-control RPP to the left kidney. Arterial catheters were used to measure MAP above and below the occluder (n=5).

Baseline RPPs were measured on a control salt diet (0.4% NaCl) for 3-days (average left RPP, 124±1mmHg) after which rats were switched to a HS diet (4.0% NaCl) for 14-days. During the first 7-days of HS both kidneys were exposed to uncontrolled hypertension. After 7-days a servo control system was used to bring the RPP to the left kidney (the reversal kidney) back to the average control level, where it was held for the next 7-days of HS (from 139±2mmHg to 125±2mmHg). It was found that reversal of hypertension prevented a further increase of renal T-cell infiltration but the number of infiltrated T-cells did not diminish. Moreover, the number of T-cells in the left-reversal kidney was significantly higher than in the continuously-controlled, left-servo kidney despite comparable final RPPs (129±2mmHg to the left-servo kidney vs. 125±2mmHg to the left-reversal kidney). T-cell infiltration in the left-reversal kidney was comparable to the left-sham kidneys, in which in the final RPP was 148±2mmHg.

In ‘T-cells per kidney’-

CD3+ (mature): Reversal=287x10
3
±65x10
3
Servo=78x10
3
±12x10
3
Sham=186x10
3
±47x10
3
.

CD3+CD4+ (helper): Reversal=95x10
3
±27x10
3
Servo=32x10
3
±5x10
3
Sham=86x10
3
±26x10
3
.

CD3+CD8+ (cytotoxic): Reversal=196x10
3
±42x10
3
Servo=42x10
3
±7x10
3
Sham=102,082x10
3
±23x10
3

We conclude that reversal of blood pressure alone, for 1-week, while HS intake is continued, stops but does not reverse renal T-cell infiltration in SS rats.
Abstract 123: A Fructose-enriched Diet Stimulates Superoxide Production in Juxtaglomerular Cells and Prevents High-salt Induced Inhibition of Plasma Renin Activity (PRA)
Authors: Mendez Mariela , Gordish Kevin L , Henson Emily , Ortiz Pablo A , Beierwaltes William H
Published: June 2021

A fructose-enriched diet has been associated with hypertension. Western diets are rich in fructose and salt. We found that a fructose enriched diet plus high-salt induced salt sensitive hypertension. Plasma renin activity (PRA) is essential for blood pressure (BP) control. A high-salt diet decreases PRA by inhibiting renin release from juxtaglomerular (JG) cells. However it is not known if dietary fructose might impair the inhibition of renin release by high salt to promote salt sensitivity. Salt sensitive rats have enhanced levels of superoxide in the renal cortex, and we found that superoxide stimulates renin release from JG cells. Thus, we hypothesized that a fructose-enriched diet (20%) promotes salt sensitive hypertension in part by preventing high salt-induced inhibition of renin release from JG cells by enhancing superoxide production. To test this, Sprague Dawley rats were given 20% fructose in their drinking water, with normal or high salt diet (4% NaCl) for up to 4 weeks. Feeding normal rats a fructose+High-salt diet increased systolic BP by 30 mmHg whereas fructose or high-salt alone did not change BP (High-salt = 125±4, Fruct = 131±4, Fruct+High-salt = 147±7; n=6,
p
<0.05). A high-salt diet alone for 4 weeks decreased PRA by 85%. However, in rats fed fructose+High-salt did not decrease PRA (in ng AII/ml/hr: Ctrl = 2.51±0.72, High-salt = 0.43±0.07, Fruct = 2.71±0.9, Fruct+High-salt = 1.89±0.43; n=10,
p
<0.05). We next examined the role of the fructose or fructose+High-salt diet on NADPH oxidase expression in isolated JG cells. NOX4 expression was enhanced in JG cells from rats fed fructose+High-salt diet (n=4;
p
<0.05). Next, we measured superoxide production with Dihydroethidium and found it was higher in JG cells from rats fed fructose+high-salt diet compared to high-salt alone (% of Ctrl: High-salt = 90.7±37; fruct+High-salt = 289±85; n=4;
p
<0.05). We conclude that a 20% fructose-diet promotes salt sensitivity of BP. The mechanism may involve enhanced NOX4 expression and elevated superoxide levels within JG cells stimulating renin release. 15 million Americans consume 20% of their calories from fructose, and most, 4-8 times the recommended salt intake. Decreasing fructose intake could have a beneficial BP effect in hypertensive patients.
Abstract 129: The Role of Intron-2 Conversion Polymorphism in the Regulation of Human Aldosterone Synthase Gene Expression
Authors: Mopidevi Brahmaraju , Perla Sravankumar , Sivankutty Indu , Kumar Ashok
Published: June 2021

The hCYP11B2 gene encodes aldosterone synthase, the rate-limiting enzyme in the biosynthesis of aldosterone. Inappropriate excess levels of aldosterone induces positive sodium balance and predisposes to hypertension and other cardiovascular problems. hCYP11B2 has a T/C polymorphism located at -344 in its promoter region. This variant is in close linkage disequilibrium with a complex hCYP11B2 Intron 2 conversion polymorphism (IC), which replaces a segment of DNA within intron 2 with the corresponding region of hCYP11B1. Epidemiological studies have suggested that -344 T/C and the IC polymorphism associating with hypertension. The IC polymorphism always occur when the promoter contains -344T variant. In the present study we have for the first time sequenced the full length hCYP11B2 intron 2 from randomly selected hypertensive samples from the Caucasian cohort and identified the segment of hCYP11B2 replaced by that of hCYP11B1 Intron2. It is interesting to note that in these genomic DNA samples there is no change in the hCYP11B1 intron2 sequence.
In silico
transcription factor binding site predictions indicate that there are several transcription factors which can bind more strongly to the hCYP11B2 IC region as compared to wild type intron2 (wt). We have cloned the IC polymorphism and the wt intron nucleotide sequences in front of the 1kb hCYP11B2 promoter containing -344T. These reporter constructs showed differential transcriptional activation. Basal promoter activity of IC intron was increased by 1.94 fold (p<0.05) compared to that of wt intron2. Further co-transfection studies of these reporter constructs along with transcription factors HNF3B and NFkB showed significantly increased relative luciferase activity of 2.9 and 3.26 fold (p<0.05) in IC construct as compared to wt intron respectively. These results strongly suggest that IC in hCYP11B2 has strong regulatory elements as compared to the wt intron leading to enhanced transcriptional activity and thus increased hCYP11B2 gene expression. This would increase tissue or plasma aldosterone levels in human subjects containing IC polymorphism. The long term consequence of altered regulation of aldosterone production can lead to an increase in blood pressure and cardiovascular complications.
Abstract 130: Modulation of Salt and Mineralocorticoid Sensitivity of Blood Pressure by the Circadian Clock Protein Per1
Authors: Solocinski Kristen , Wen Xuerong , Cheng Kit-Yan , Lynch Jeanette , Cain Brian D , Wingo Charles S , Gumz Michelle L
Published: June 2021

The circadian clock is important for maintaining rhythms in physiological functions including blood pressure (BP). Circadian disruption leads to increased disease risk. The clock has also been implicated in the maintenance of a normal dip in BP at night. In humans, non-dipping (night/day difference in BP<10%) is associated with an increased risk of cardiovascular and kidney disease. Dipping status can also be affected by salt intake and by hormones such as the mineralocorticoid aldosterone. The goal of this study was to determine the effects of a high salt (HS, 4% NaCl) diet plus mineralocorticoid (deoxycorticosterone pivalate (DOCP)) on BP regulation by the circadian clock protein Per1 in C57BL/6J mice. BP was monitored in conscious, unrestrained male mice by radiotelemetry and values are reported as mean arterial pressure (MAP) ± SEM. Under control conditions, MAP in male WT mice was 112.5 ± 1.08 mmHg during the night when mice are active and decreased to 102.1 ± 1.7 mmHg during the day, a “dip” in MAP of 9.2 ± 1.3%. Similarly, Per1 KO mice dip 14 ± 1.4%, with night time MAP of 119.8 ± .9 mmHg which decreased to 103 ± 1.4 mmHg during the day. On HS/DOCP, WT mice MAP decreased from 114.5 ± 1.1 mmHg to 101.5 ± 1.92 mmHg (night indicated by shaded bars in figure). This 11.4 ± 1.9% dip in WT mice was not significantly different from what was observed under control conditions. In contrast, Per1 KO mice display a significantly attenuated dip of 5.7 ± 1.4% with night time MAP of 125.3 ± 1.5 mmHg dropping to 118.1 ± 1 mmHg during the inactive day period (p<0.05). Thus, HS/DOCP treatment in Per1 KO mice leads to non-dipping hypertension. This is the first report of this phenotype in a single clock gene KO.
Abstract 131: Quantification of
in vivo
Placental Oxygenation Using Ultrasound-guided Spectral Photoacoustic Imaging
Authors: Bayer Carolyn , Luke Geoffrey P , Cook Jason R , Emelianov Stanislav Y
Published: June 2021

Preeclampsia, linked to abnormal placental development and ischemia, is a major cause of fetal and maternal death. Currently, the only cure is high-risk preterm delivery. Although clinical therapies to regulate the symptoms of preeclampsia—mean arterial pressure and proteinuria—it is unknown whether these therapeutics restore placental blood flow and reduce ischemia. We are developing ultrasound-guided spectral photoacoustic imaging to quantify placental ischemia and characterize therapeutic response. Ultrasound imaging is the preferred imaging modality to monitor pregnancy due to its safety, low cost, and mobility. Similar to ultrasound, photoacoustic imaging can provide co-registered images of tissue function. In these studies, pregnant SWV mice were imaged longitudinally from E12.5 to 18.5 using a Vevo LAZR small animal imaging system. Algorithms were developed to correlate the spectral photoacoustic data to a hemoglobin oxygenation (%sO
2
) calibration standard—a phantom containing blood at varying partial pressures of oxygen. The phantom calibration standard deviation was 7.9% (n=3). The resulting ultrasound images were used to segment the placenta (Figure 1). An overlay of the %sO
2
on the ultrasound image maps placental variation in %sO
2
during longitudinal development. We demonstrate that our imaging method is capable of quantifying %sO2 and monitoring placental function
in vivo
. Future work will use our preclinical %sO2 quantification methods to characterize placental function during treatment for preeclampsia.
Abstract P101: Assisted Reproductive Technologies Increase the Vasoconstrictor Responsiveness to Angiotensin II by an Epigenetic Mechanism
Authors: Meister Theo A , Soria Rodrigo , Rexhaj Emrush , Stenz Ludwig , Paolini-Giacobino Ariane , Dogar Afzal , Sartori Claudio , Scherrer Urs , Rimoldi Stefano F
Published: June 2021

Environmental influences acting early in life predispose to premature cardiovascular disease. In line with this concept, assisted reproductive technologies (ART) cause premature vascular ageing and arterial hypertension in mice and humans, but the underlying mechanisms are incompletely understood. In rodents, pathological events during pregnancy cause arterial hypertension in the offspring by increasing the vascular responsiveness to angiotensin II (ANG II). We speculated that a similar mechanism could be involved in ART-induced arterial hypertension. In aortic ring preparations of ART and control mice, we, therefore, assessed the vasoconstrictor responsiveness to stepwise increasing doses of ANG II in the presence of the eNOS inhibitor L-NMA. We also examined ANG II receptor (AGTR) type 1 and 2 expression (Western Blot) and AGTR gene promoter methylation (bisulfite sequencing) in the aorta. Finally, we measured mesenteric-artery responsiveness to acetylcholine and arterial blood pressure (carotid catheter). As expected, ART mice displayed endothelial dysfunction (P=.03, vs. control) and arterial hypertension (121.8±7.3 vs. 114.6±4.5 [mmHg], P=.02, vs. control). Most importantly, the vasoconstrictor response to ANG II, independently of endothelial function, was markedly increased in ART compared to control mice (0.32±0.05 vs. 0.22±0.04 [% of maximal KCl contraction], P<.01, vs. control). Moreover, and in line with this finding, in ART mice AGTR 1/AGTR 2 ratio of protein expression in the aorta was significantly increased (1.49±0.30 vs. 0.36±0.16, P<.008, vs. control) and the AGTR 1b gene promoter was hypomethylated compared with control mice (8.1±4.3 vs. 10.6±1.6 [% of methylation], P<.05, vs. control). Here, we show for the first time that ART increases the vasoconstrictor sensitivity to ANG II in the aorta. This is related to an epigenetically mediated imbalance between the expression of the vasoconstrictor (AGTR 1) and vasodilatator (AGTR 2) ANG II receptor. Hence, we identified a new mechanism contributing to ART-induced premature vascular ageing and arterial hypertension in mice. We speculate that this mechanism also contributes to ART-induced premature vascular ageing and arterial hypertension in humans.
Abstract P106: Effects of Aldosterone Excess and Sodium on Dipping Patterns in Resistant Hypertensive Patients
Authors: German Charles
Published: June 2021

Background:
High dietary sodium intake and aldosterone excess have been independently linked to increased cardiovascular morbidity and mortality. In addition, a large body of literature indicates that aldosterone excess contributes importantly to antihypertensive treatment resistance and is associated with higher 24- hour ambulatory blood pressure (BP) levels.

Objective:
This study was designed to determine if high dietary sodium intake, and hyperaldosteronism combine to mediate the development of abnormal diurnal BP patterns including nocturnal hypertension and dipping BP patterns.

Methods:
A single-center cohort of 326 African American (AA) and Caucasian resistant hypertensive patients were prospectively evaluated by assessing 24-hr urinary aldosterone (UAldo), plasma renin activity (PRA), sodium (UNa
+
) levels, and 24-hr ambulatory blood pressure monitoring (ABPM). Daytime, night-time, and 24-hr BP and dipping patterns were determined. High sodium excretion was defined as UNa
+
= 200 mEq/24hr and hyperaldosteronism was defined as UAldo = 12 μg/24hr and PRA ≤ 1 ng/ml/hr.

Results:
There was no difference in ABPM and dipping patterns when comparing the normal versus high sodium group. However, patients without high sodium excretion had better nocturnal (p=0.024) and 24- hour BP control (p=0.036). Furthermore, there was no difference in ABPM patterns when comparing patients with high versus normal sodium excretion with hyper versus non- hyperaldosteronism. Interestingly, in the group with hyperaldosteronism, patients with normal sodium excretion had improved dipping patterns, but only in the dipper group (p=0.016).

Conclusions:
High dietary sodium intake contributes to increased nocturnal hypertension and poor 24-h BP control, but there does not seem to be a significant relationship between hyperaldosteronism and high dietary sodium intake. This data suggests that improvements in dietary sodium intake will lead to better control of nighttime BP and 24-h BP control and therefore reduces the risk of cardiovascular disease. Further studies are underway comparing these relationships in males versus females, and AAs versus Caucasians.
Abstract P109: Spiny Mice Are Protected From Myocardial Infarction Induced Cardiac Pathophysiology
Authors: Qi YanFei , Zhang Juan , Wang Lei , Kumar Ashok , Mandloi Avinash , Vohra Ravneet , Walter Glenn A , Yarrow Joshua F , Gupta Dipankar , Katovich Michael J , Raizada Mohan K , Pepine Carl J
Published: June 2021

Background:
Despite the advancement in drug and surgical interventions, myocardial damage and associated cardiac dysfunction lead to heart failure that remains common cause of death following myocardial infarction (MI). Spiny mice (Acomys cahirinus, SM) have been shown to possess regenerating capacity following deep tissue injury without scarring (
Nature 2013
). This led us to investigate if this regenerative property would also be preserved in the heart.

Methods and Results:
Adult CD1 and SM were subject to left anterior descending coronary artery ligation or sham surgeries. Proliferative cells were identified by nuclear incorporation of 5-bromodeoxyuridine (BrdU, daily, i.p.) and injection was started from 3d post MI continued to 2wks post MI. Cardiac function was assessed using echocardiography and MRI. SM exhibited 3-fold smaller infarct size (SM-MI 18.6±3.4% vs CD1-MI 76.2±3.4%, p<0.05) and better contractility measured by ejection fraction (SM-MI 77.1±6.5 vs CD1-MI 24.6±4.6, %, p<0.05) than CD1 mice. SM showed 6-fold increase in BrdU
+
cells in left ventricle after MI while CD1 mice had 4-fold increase (CD1-sham 11±3.5 vs CD1-MI 44±9.1 and SM-sham 16±9.8 vs SM-MI 101.1±30.9, p<0.05). Though basal cardiac ACE2 activity was not different between CD1 and SM, MI resulted in a 16% decrease in cardiac ACE2 activity in CD1-MI mice but 20% elevation of cardiac ACE2 activity in myocardial tissue in SM-MI.

Conclusions:
SM are protected from ischemia induced cardiac damage and dysfunction. This involves increased proliferating cardiac cells and reduction in infarct size. Thus SM could be an ideal animal model for identification of molecular and genetic circuits involved in preservation/regeneration of cardiac function with translational implication to human MI.
Abstract P117: A Conserved Trans-membrane Domain Lysine in the Integrin Beta1 Subunit Regulates Renal Collecting Duct Cell Function
Authors: Mathew Sijo , Chen Jiang , Lu Zhenwei , Sanders Charles , Zent Roy
Published: June 2021

Integrins are heterodimeric trans-membrane receptor proteins that mediate the interaction of cells with extracellular matrix proteins (ECM). They mediate various growth factor dependent cell-signaling pathways during the development of fibrosis that is characteristic of all forms of chronic kidney diseases. Although integrin β1 is the most abundant integrin subunit in kidney and can form complexes with 12 different α subunits, integrin β3 is the best studied integrin β subunit and serves as the canonical model for integrin function based on the high sequence homology between the trans-membrane and cytosolic domains of integrin β subunits. A conserved lysine residue towards the C-terminus of integrin β3 subunit is reported to be important for regulating the activation of integrin αIIbβ3 complexes; however the functional importance of this lysine is unknown in β1 integrins. We investigated the role of this lysine residue in integrin β1-dependent kidney collecting duct cell function. We expressed the mutant protein where the lysine is mutated to glutamic acid in collecting duct cells null for integrin β1. Collecting duct cells expressing mutant protein had decreased the adhesion of cells to collagen IV mediated by integrin α1β1 by 80% (0.95 vs 0.18). This mutation also decreased the ability of IMCD cells adhesion to collagen I mediated by integrin α2β1 by 82% (0.78 vs 0.15). In contrast to earlier reports in integrin β3, this mutation did not significantly alter the amount of active integrin β1 on the cell surface as estimated by FACS analysis; however we did observe a decrease in conformation specific antibody binding on cells adhered to collagen (0.70 vs 0.30). We also investigated the role of this lysine residue in complex formation of purified integrin β1 with integrin α1 and α2 TM/CT domains in phospholipid bicelles using fluorescence anisotropy. The dissociation constant for binding was estimated to be >3.2 mol and mutation of lysine residue did not significantly alter their binding ability. This contrasted with integrin αIIb β3 where we found fourfold decrease in binding ability (Kd 0.09 ± 0.03 mol and 0.33 ± 0.05 mol). Our data clearly suggest that conserved transmembrane lysine in both integrin β3 and integrin β1 regulate cell functions by distinct mechanisms.
Abstract P119: Association Between Inspiratory Muscle Strength and Sympathetic Cardiac Modulation and Baroreflex in Patients With End Stage Renal Disease Undergoing Hemodialysis
Authors: Scapini Kátia B , Souza Silvia B , Hong Valéria C , Moraes Oscar A , Machi Jacqueline F , Mostarda Cristiano T , Consolim-Colombo Fernanda M , Irigoyen Maria C
Published: June 2021

Introduction:
Patients with end-stage renal disease (ESRD) are susceptible to development of autonomic dysfunction and have metabolic and muscular changes which are associated with decreased functional capacity.

Objectives:
To evaluate respiratory muscle strength and cardiac autonomic modulation in ESRD patients undergoing hemodialysis.

Methods:
ESRD patients undergoing hemodialysis (n= 9, mean age 46.2±14.1 years) and healthy controls (n =7, mean age 44.6±14.6 years) were assessed. Non–invasive curves of blood pressure were recorded continuously (Finometer ®) for 10 minutes. The heart rate variability was estimated in the time and frequency domain. Inspiratory and expiratory maximal pressures (IPmax and EPmax) were quantified using a pressure transducer. Mann-Whitney and Spearman tests were used. The results were expressed as mean ± SD.

Results:
Regarding respiratory muscle strength, ESRD patients had lower inspiratory (IPmax: 79.1±25.0 vs 121.3±24.3cmH
2
O, p=0.03) and expiratory muscle strength (EPmax 92.8±23.1 vs 153.8±23.5cmH
2
O, p=0.01) then healthy controls. ESRD patients presented lower heart rate variability than healthy controls (SDNN: 19.2±4.0 vs 52.6±18.8ms, p=0.000) and lower RMSSD, an index of vagal modulation (11.8±5.2 vs 46.1±20.4ms, p=0.000). Regarding frequency domain indexes, ESRD patients presented higher low-frequency component (LFnu= 68.9±11.9 vs 47.3± 2.8, p=0.008), lower high-frequency component (HFnu= 31.1±11.9 vs 52.7±12.8, p=0.008) and higher sympathovagal balance (LF/HF: (LF/HF= 3.1±1.3 vs 1.1±0.5, p=0.005) when compared to controls. Furthermore baroreflex sensitivity was reduced in ESRD patients (alfa index: 3.6±1.6 vs 11.7±4.4ms/mmHg, p=0.002). In ESRD patients the IPmax was significantly associated with LF (r=-0.813, p=0.014) and with alfa index (r=-0.900, p=0.037).

Conclusion:
ESRD patients undergoing hemodialysis presented reduced inspiratory muscle strength, increased sympathetic modulation and reduced cardiac vagal modulation and impaired baroreflex sensitivity. In these patients inspiratory muscle strength was associated with sympathetic cardiac modulation and baroreflex.
Abstract P123: Prevalence of Angiotensin Converting Enzyme Inhibitor-induced Cough and Impact on the Quality of Life of Hypertensive Patients in a Tertiary Health Institution in Nigeria: A Pilot Study
Authors: Eze Chinwe E , Oloidi Anuoluwapo D
Published: June 2021

Background/Objective:
Angiotensin Converting Enzyme (ACE) inhibitors have widespread use and have been shown to be cardio- and reno-protective. However they have a class side effect of dry persistent cough that has been shown to have a significant impact on the physical, social and psychological health of patients. This study was carried out to determine the prevalence of ACE inhibitor-induced cough and to assess its impact on the quality of life of hypertensive patients in Lagos University Teaching Hospital (LUTH), Nigeria.

Method.
The study was centered at the outpatient cardiology clinic of LUTH. It was a cross sectional descriptive study with the use of interviewer-administered validated structured questionnaires. The Leicester Cough Questionnaire (LCQ) was used to assess the effect of the cough on the patients quality of life while the Visual Analogue Scale assessed the severity of the cough. Ethical clearance was obtained from the Research and Ethics committee of LUTH and patients consent sought prior commencement of the study. The data obtained was analyzed using SPSS version 20.0 and represented as simple percentages and frequencies. Bivariate analysis was carried out using chi square test. A p-value <0.05 was considered statistically significant.

Result:
Out of the 101 patients interviewed, 20 patients had experienced ACE inhibitor-induced cough giving a prevalence of 19.8%. The prevalence of the cough was also found to be higher in females (13.86%, 14 of 20) than in males (5.94%, 6 of 20). An LCQ mean score of 13.895 was obtained which showed an average quality of life of the patients. The cough symptom severity results also showed that 40% ( 8 of 20) of the patients had a mild cough, 35% ( 7 of 20) had a moderate cough and 25% ( 5 of 20) had a severe cough.

Conclusion:
Dry cough is a relatively common side effect associated with ACE inhibitor therapy. The cough induced had an average impact on quality of life and was not severe enough to lead to discontinuation of the ACE inhibitor therapy in most patients.
Abstract P135: 2-methoxyestradiol Minimizes Angiotensin II-induced Hypertension and Renal Dysfunction in Ovariectomized Female and Intact Male Mice
Authors: Pingili Ajeeth K , Thirunavukkarasu Shyamala , Khan Nayaab S , Katsurada Akemi , Majid Dewan S , Navar Gabriel L , Malik Kafait U
Published: June 2021

Men and post-menopausal females are more prone to develop hypertension and renal dysfunction as compared to pre-menopausal females. It is well documented that in various experimental models of hypertension, the protection against hypertension in females is lost following ovariectomy (OVX). Recently we have shown that CYP1B1 protects against angiotensin II (Ang II)-induced hypertension and associated cardiovascular changes in female mice, most likely via production of 2-methoxyestradiol (2-ME). This study was conducted to determine if 2-ME reduces Ang II-induced hypertension, renal dysfunction and end organ damage in OVX female, and intact male mice. Treatment of OVX

Cyp1b1
+/+

and

Cyp1b1
-/-

female mice with 2-ME (1.5 mg/kg/day i.p., for 2 weeks) reduced Ang II-induced increase in systolic blood pressure (SBP) (182±5.1 vs. 143± 2.4 mmHg, 179±6.4 vs. 140± 8.6 mmHg, P < 0.05, n= 5), water consumption, urine output and osmolality, and proteinuria (5.5±0.7 vs. 3.3±0.5 mg/24 hrs, 8.4±1.3 vs. 4.4 ±0.9 mg/24 hrs) respectively. 2-ME also reduced Ang II-induced increase in SBP (188±2.6 vs. 143± 2.7 mmHg, P < 0.05, n= 5) in intact male mice. 2-ME did not alter water consumption and urine osmolality, but reduced urine output and sodium excretion, and proteinuria (14.4±2.0 vs. 6.0±0.5 mg/24 hrs) in intact

Cyp1b1
+/+

male mice. Treatment with 2-ME attenuated Ang II-induced end-organ damage (actin and collagen accumulation) in OVX

Cyp1b1
+/+

and

Cyp1b1
-/-

female and

Cyp1b1
+/+

male mice. 2-ME mitigated urinary excretion of angiotensinogen in OVX

Cyp1b1
+/+

and

Cyp1b1
-/-

female mice infused with Ang II. These data suggest that 2-ME reduces Ang II- induced hypertension and associated renal dysfunction and end-organ damage in OVX

Cyp1b1
+/+

and

Cyp1b1
-/-

female, and intact male mice. Therefore, 2-ME could serve as a therapeutic agent for treatment of hypertension and associated pathogenesis in post-menopausal females, and intact males.
Abstract P136: Dietary Salt and Non-Salt Components Have Substantial Effects on Genome-Wide DNA Methylation Patterns in Dahl SS Rats
Authors: Abais-Battad Justine M , Liu Pengyuan , Mattson David L , Liu Yong , Cowley Allen W , Kurth Theresa M , Yang Chun , Lund Hayley , Geurts Aron M , Kidambi Srividya , Kotchen Theodore A , Liang Mingyu
Published: June 2021

Epigenetic modifications of the genome play a key role in the regulation of gene expression. It has been reported that epigenetic modifications of several genes are associated with hypertension. To investigate the potential role of genome-wide changes in DNA methylation in salt-induced hypertension, experiments were performed on inbred Dahl SS rats obtained from two colonies maintained at the Medical College of Wisconsin (i.e. MCWSS) and Charles River Laboratory (CRLSS). The colonies are genetically identical, but CRLSS rats were maintained on a whole grain diet containing 1% NaCl (CRLSS_LS) while MCWSS rats were fed casein-based AIN-76A chow containing 0.4% NaCl (MCWSS_LS) until both colonies were switched to an AIN-76A chow containing 4% NaCl for 14 days starting at 6 weeks of age (CRLSS_HS and MCWSS_HS, respectively). Mean arterial pressure and albumin excretion rate in MCWSS_HS rats were significantly greater (142±14 mmHg and 100±16 mg/day, n=6) than in CRLSS_HS rats (118±2 mmHg and 20±2 mg/day, n=7). Reduced representation bisulfite genome sequencing (RRBS) measured 5-Methylcytosine levels at single-base resolution in the renal outer medulla in the above groups, each with four biological replicates. For genomic regions located within CpG islands (CGI’s) and exhibiting differential methylation between LS and HS in each colony, HS diet increased median methylation levels several-fold in both MCWSS (7.45% vs. 0.35% for MCWSS_HS vs. MCWSS_LS, respectively, p = 2.84E-31) and CRLSS rats (7.62% vs. 1.21% for CRLSS_HS vs. CRLSS_LS, respectively, p = 1.65E-32). For genomic regions exhibiting differential methylation between MCWSS and CRLSS, MCWSS_HS rats (which exhibited higher blood pressure) had higher median methylation levels than CRLSS_HS rats (7.56% vs. 2.75%, p = 2.12E-9). We observed 156 hypermethylated and 241 hypomethylated regions within CGI’s of MCWSS_LS compared to CRLSS_LS. Examples of differentially methylated genes include the serine protease
Prss2
, the transcription factor
E2f1
, and the matrix protein
Spock2
. These results suggest that sodium-dependent and independent dietary components could induce changes in DNA methylation that may predispose and participate in the development of hypertension and renal damage.
Abstract P143: Hypertension and Inflammation-Related microRNAs
Authors: Hijmans Jamie G , Bammert Tyler D , Kavlich Philip J , Diehl Kyle J , Lincenberg Grace M , Levy Ma’ayan V , Greiner Jared J , Stauffer Brian L , DeSouza Christopher A
Published: June 2021

microRNAs (miRs) are short single stranded noncoding RNAs that are involved in the regulation of a number of physiological and pathological processes. miRs down regulate target gene expression post-transcriptionally by degrading messenger RNA and/or by blocking translation. It is now recognized that miRs play a key role in regulating inflammation, vascular health and in-turn, cardiovascular disease (CVD). For example, altered expression of specific miRs such as, miR-126, miR-146a and miR-150 have been linked with heightened vascular inflammation and CVD risk. Hypertension is associated with increased inflammatory burden. The mechanisms underlying blood pressure-related inflammatory stress are not fully understood. It is currently unknown whether inflammation-related miRs are dysregulated with elevated blood pressure. Accordingly, the aim of this ongoing study is to determine the influence of hypertension, independent of other risk factors, on circulating expression of miR-34a, miR-92a, miR -126, miR-146a and miR-150. To date, 28 sedentary, middle-aged adults have been studied: 14 normotensive (NT; 12M/2F; age: 53±1 yr; BP: 114/71±2/1 mmHg) and 14 hypertensive (HT; 12M/2F; 56±2 yr; 142/90±2/2 mmHg). All subjects were non-smokers, normolipidemic, non-medicated and free of overt CVD. Circulating expression of miRs was determined in plasma using standard RT-PCR techniques with miR primers of interest. Expression was normalized to exogenous C.
elegans
miR-39 and reported as relative expression in arbitrary units (AU). Circulating expression of miR-126 (0.14±0.03 vs 0.33±0.04 AU) and miR-150 (0.06±0.02 vs 0.12±0.02 AU) were markedly lower (~135% and 100%, respectively; P<0.05) in the HT vs NT groups. There was no significant group difference in miR-34a (0.017±0.005 vs 0.010±0.001 AU), miR-92a (0.66±0.16 vs 1.01±0.13 AU) and miR-146a (0.04±0.01 vs 0.06±0.01 AU). Lower expression of miR-126 and miR-150 is consistent with a proinflammatory phenotype, as both are involved in limiting inflammatory pathways. In summary, these initial results suggest that dysregulation of key inflammation-related miRs may contribute mechanistically to the heightened inflammatory state associated with elevated blood pressure and deserve further study.