bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 266: Effects Of Carotid Body Tumor Resection On Blood Pressure
Authors: Fudim Marat , Groom Kelly L , Laffer Cheryl L , Netterville James L , Robertson David , Elijovich Fernando
Published: July 2021

Introduction:
Removal of carotid body (CB) improves rodent models of HTN and HF, presumably via withdrawal of chemoreflex-induced sympathetic activation. CB tumor (CBT) resection abolishes the chemoreflex in humans and is associated with opposing effects on sympathetic regulation by accompanying damage of the baroreflex. The net effect of CBT removal on BP in subjects with pre-existent HTN is unknown.

Methods:
Retrospective analysis of 134 patients with uni- or bilateral CBT resection between 1990-2012. Twenty subjects met HTN entry criteria (BP≥140/90 mmHg or use of antihypertensive drugs) but two were excluded from analyses because of inadequate data. BP changes were assessed by a) acute ΔSBP: the change from the average SBP for the 3 months preceding surgery to the first reading after 30 days from the procedure, and b) chronic: the slope of the regression of SBP on time over the entire follow up, expressed as ΔSBP/year. BP changes were adjusted with covariate analyses. Covariates for acute ΔSBP were: the interval between pre and post BP readings and the change in therapy during this interval (assessed by a score of medications based on equipotency). Covariates for chronic ΔSBP were: total duration of follow-up, number of SBP readings and change in therapy during the entire period of study.

Results:
Age and duration of HTN were 56±4 and 10±4 years, respectively. There was a significant relationship between acute ΔSBP and the chronic slopes (r=0.47, p<0.05) indicating that initial BP responses to CBT removal tend to be sustained. The univariate relationship showed that for every change of 0.4 mmHg in acute ΔSBP, there was a concomitant 1 mmHg/yr change in the chronic slope. Thirteen subjects (72%) had concordant reductions of ΔSBP and slope of any magnitude. In 6 subjects (33%), acute ΔSBP was ≥ -10 mmHg (corresponding to concomitant slopes ≥ 5.9 mmHg/yr).

Conclusions:
This is the first study to show that CBT removal is associated with a sustained reduction of BP in a subset of patients with comorbid HTN. Also, concomitant baroreceptor damage by CBT removal most likely leads to underestimation of the depressor effect of chemoreflex disruption. Development of a targeted removal of CB chemoreflex may conceivably have a role in the therapy of human hypertension.
Abstract 268: The Increased Visceral Fat Thickness In Nafld Patients Enhances The Risk Of Coronary Artery Stenosis
Authors: CAO PENG Y , CAI HE , LIU MIN , ZHANG XIN Y , YU SHUI , ZHENG YANG
Published: July 2021

Background:
Non alcoholic fatty liver disease (NAFLD) is an independent risk factor of cardiovascular disease (CVD). In this research, we want exploring the relationship between NAFLD, visceral fat thickness and the severity of coronary artery disease.

Methods:
1, The relationship between NAFLD, visceral fat thickness and severity of coronary heart disease(323 people).

2, The correlation between severe NAFLD and visceral fat thickness in the severe stenosis of coronary heart disease(197 people).

Results:
1, the proportion of NAFLD was significantly increased by 16% and 19% in different coronary artery stenosis than in the normal group. Along with the increasing degree of coronary artery stenosis, the total visceral fat thickness increase, especially the epicardial layer (the moderate stenosis increased by 23% and the severe stenosis increased by 54% than without stenosis).

2, In the severe coronary artery stenosis group, the patients were divided into NAFLD group and non NAFLD group. compared to non NAFLD group, the epicardial, liver, renal, before the perirenal fat and the coronary score significantly increased in the NAFLD group (10%, 22%, 32%, 36% and 27%, respectively) .Along with the increase of coronary score , the epicardial fat thickness was increased significantly (16% and 34%, respectively) in the non NAFLD group; but the epicardial thickness of the NAFLD group was slightly increased (8% and 8%, respectively), there was no significant difference among the subgroups. Furthermore,not only in NAFLD group but also in non NAFLD group, the visceral fat thickness of the other three sections have no significant change among the three subgroups.

Conclusion:
Both the NAFLD and the epicardial adipose layer thickening can increase the risk of coronary artery stenosis. In the patients with the severe coronary artery stenosis, the NAFLD patients are more likely to increase the accumulation of the visceral fat thickness than the non NAFLD patients. Under the same thickness of the epicardium, the degree of coronary artery lesions is lighter in the NAFLD patients; it may be related to AMPK wich may have the myocardial protective effects.
Abstract 275: High Fat Diet-induced Decreases In Insulin Signaling In Afferent Renal Nerves Are Prevented By Intrathecal Injection Of Metformin In Rats
Authors: Yu Shuang-Quan , Wang Donna H
Published: July 2021

Metformin, an anti-type 2 diabetic agent that increases insulin sensitivity in target tissues, has been suggested having neuroprotective effects. Our previous data showed that metformin protects against high fat diet (HFD)-induced impairment in renal afferent nerves that express the transient receptor potential vanilloid 1 (TRPV1) channels, and prevents HFD-induced renal functional deterioration and hypertension. However, mechanisms of metformin-mediated neuroprotection are largely unknown. This study tests the hypothesis that HFD impairs insulin signaling in afferent renal nerves, which is prevented by metformin via the pathway of IRS-1-tyr, AMPK, and GLUT-1/3. Metformin (1 ng/kg, daily intrathecal injection via indwelled catheters to segments T8-L3 supplying the kidneys) or vehicle was given to rats fed a HFD or normal fat diet (Con) for 8 weeks. Immunohistochemical staining showed that insulin receptor substrate-1 phosphorylated with serine (p-IRS-1-ser), insulin receptor substrate-1 phosphorylated with tyrosine (p-IRS-1-tyr), phosphorylated AMP-activated protein kinase (p-AMPK), glucose transporter 1 (GLUT-1), and GLUT-3 were expressed in dorsal root ganglia (DRG). Levels of p-IRS-1-ser were increased by HFD but decreased by metformin in Con rats, and HFD-induced increases in p-IRS-1-ser were prevented by metformin. Levels of p-IRS-1-tyr, p-AMPK, and the trafficking of GLUT-1 and GLUT-3 from cytoplasma to cell membrane in DRG were decreased by HFD but increased by metformin in Con rats, and HFD-induced decreases in these parameters were prevented by metformin (p-IRS-1-tyr, Con: 0.23±0.02, Con+Met: 0.34±0.04, HFD: 0.14±0.02, HFD+Met: 0.22±0.03, p<0.05). Afferent renal nerve activity (ARNA) in response to insulin perfusion into the renal pelvis was decreased by HFD but enhanced by metformin in Con rats, and HFD-induced decreases in ARNA was prevented by metformin. Our data showed that HFD decreases insulin signaling in afferent renal nerves, which is prevented by metformin injected intrathecally to segments innervating kidneys. These data indicate that metformin may constitute neuroprotecitve effects via improving insulin signaling in afferent renal nerves via activation of the pathway of IRS-1-tyr, AMPK, and GLUT-1/3.
Abstract 285: Reduced Parasympathetic Activity and Correlation with Plasma Resistin Levels in High Fat Diet Mice
Authors: Hartnett Sigurd , Li Yifan
Published: July 2021

A trait of most cardiovascular diseases, obesity, and aging is autonomic imbalance with increased sympathetic and decreased parasympathetic activity. While the hyperactive sympathetic nervous system has been extensively researched, little attention has been given to the mechanisms involved in the reduction of the parasympathetic nervous system. This study investigates the peripheral regulation of the parasympathetic nervous system and its association with plasma resistin levels in a high fat diet mice model of obesity.

Male ICR mice were fed a high fat diet (HFD) or low fat diet (LFD) for 14 weeks. At the end of the diet regimen, mice underwent vagal stimulation (VS) tests and were sacrificed for blood and tissue collection. For VS, under anesthesia of intraperitoneal injection with urethane (2 g/kg), the right cervical vagus nerve was stimulated at 2 to 10Hz with pulses of 2ms and 2V while the heart rate was monitored with ECG. The reduction of heart rate by VS was significantly attenuated at 10Hz in HFD mice as compared to LFD mice (-121.3 beats per minute, 95% Confidence Interval [CI] -178 to -64.63, p<0.05, n=5 both groups). To evaluate the contribution of adipokines and cytokines to this reduced parasympathetic response, serum was tested using commercially available kits for resistin, adiponectin, TNFa, and IL6. Whereas no changes were observed in plasma adiponectin, TNFa, or IL6 levels, there was an significant increase in plasma resistin levels in HFD mice as compared to LFD mice (837 pg/mL, 95% CI 294-1379, p<0.01, LFD n=5, HFD n=4). Furthermore, a Pearson product-moment correlation coefficient was calculated to assess the relationship between plasma resistin level and responses in heart rate to VS. There was a strong positive correlation between these two variables (r=0.851, n=8, p<0.01). The molecular mechanisms responsible for the effects of resistin on the cholinergic, parasympathetic system are currently being investigated.

In summary, these results suggest that elevated plasma resistin levels may contribute to a reduction in parasympathetic nervous system activity associated with obesity.
Abstract 296: Sorting Nexin 19: A Novel Regulator of Renal Dopamine D
1
Receptor
Authors: Yang Jian , Villar Van A , Jones John E , Guo Yan , Asico Laureano D , Armando Ines , Weinman Edward J , Jose Pedro A
Published: July 2021

The D
1
dopamine receptor (D
1
R) plays a pivotal role in blood pressure regulation. The present study aimed to demonstrate the role of sorting nexin 19 (SNX19) in the regulation of renal D
1
R trafficking and signaling. We tested the dynamic interaction between these proteins and showed that SNX19 coimmunoprecipitated with the D
1
R, as well as with GRK4 and β-arrestin--proteins that are required for D
1
R homologous desensitization, in human renal proximal tubule cells (hPRTCs) and mouse kidney homogenates. These proteins colocalized basally at the cell membrane in hRPTCs, while treatment with the D
1
R/D
5
R agonist fenoldopam (Fen) promoted their endocytosis to the juxtanuclear area, indicating that SNX19 is involved in the agonist-activated D
1
R trafficking.
SNX19
silencing in hPRTCs reduced the D
1
R abundance (non-silencing “mock” siRNA=1.0±0.05
vs
.
Snx19
-specific siRNA=0.45±0.06,
P
<0.05, n=3/group), although D
1
R depletion did not affect SNX19 expression. SNX19 depletion also blunted the cAMP response after Fen treatment (1μM, 15min) (mock: basal=12.4±4.5 pmol/mg protein
vs
. mock+Fen=147.8±3.4;
Snx19
siRNA: basal=6.8±3.4
vs
. siRNA+Fen=63.1±5.4,
P
<0.05, n=4). Moreover, SNX19 depletion impaired the sodium transport in response to Fen treatment (1μM, 15min) (mock: Δ intracellular Na
+
from basal=
+
15.4±3.2%,
vs
.
Snx19
siRNA: Δ Na
+
=
+
3.3±7.5%,
P
<0.05, n=3). SNX19 and D
1
R colocalized at the brush border in mouse and human renal proximal tubules at the basal state. Stimulation D
1
-like receptors in mouse kidneys with the intravenous infusion of Fen (2 μg/kg/hr, 15 min) promoted D
1
R internalization with SNX19 and enhanced their colocalization at the cytoplasm. Relative to control mice, the renal selective silencing of
Snx19
in C57Bl/6J mice increased the systolic blood pressure (before injection: mock=100±5 mmHg
vs
.
Snx19
siRNA=102±2; after injection: mock=101±6
vs
.
Snx19
siRNA=118±5,
P
<0.05, n=5), and decreased renal D
1
R expression (mock=1.0±0.09
vs
.
Snx19
siRNA=0.57±0.17,
P
<0.05, n=5). Our results indicate that SNX19 is crucial to normal D
1
R function and that loss of renal SNX19 results in renal D
1
R deficiency and dysfunction. Our data suggest that the absence of SNX19 may be a novel mechanism for the pathogenesis of essential hypertension.
Abstract 301: Testosterone propionate in Ischemia-reperfusion (I/R) induced Acute Kidney Injury (AKI)
Authors: Patil Chetan N , Maranon Rodrigo O , Dalmasso Carolina , Zhang Huimin , Juncos Luis A , Reckelhoff Jane F
Published: July 2021

Acute kidney injury (AKI) is a leading cause of morbidity and mortality, and men are more prone to AKI than women implicating androgens as a causative factor whereas estrogens have been thought to be protective. These effects are independent of both androgen and estrogen receptors. We showed recently that infusion of testosterone 3 hrs post reperfusion protected rats from renal injury following ischemia/reperfusion (I/R). In the present study, we tested the hypothesis that testosterone works as a renal vasodilator perhaps by increasing nitric oxide. Male SD rats (8-14 wks; n=3-5/grp) were subjected to sham surgery or I/R induced AKI with bilateral clamping of renal vessels for 30 min. Three hrs after reperfusion, rats were given testosterone propionate (20 μg/kg iv over 10 min) or vehicle (0.75%EtOH). Rats were placed in metabolism cages for 24hrs for nitrate/nitrite excretion (UNOxV), and euthanized and blood taken for creatinine (PCr). I/R increased PCr and decreased UNOxV, compared to shams (0.58±0.05 vs. 3.99±0.36 mg/dL, p<0.0001; UNOxV: 8.54±1.7 vs 1.7±0.78 μmol/day/kg BW, p<0.001). Testosterone attenuated the increase in PCr (2.03±0.23 mg/dL, p< 0.01) but had no effect on UNOxV (3.79±0.91 μmol/day/kg). Pretreatment of rats with L-NAME (1mg/kg/day; dose that did not increase BP) for 48 hours prior to I/R abolished the improvement in PCr with testosterone (PCr: 3.73±0.82 mg/dL, p<0.05 vs no LNAME). Infusion of renal vasodilator PGE2 (30μg/kg iv over 10 min 3 hrs after reperfusion) attenuated PCr compared to I/R alone (2.95±0.21mg/dL, p<0.01) but was independent of increased NO (2.61±0.63 μmol/day/kg, p=NS vs I/R alone), and was not as effective in reducing PCr as testosterone (p<0.05). These data show that low dose testosterone infusion 3 hrs post reperfusion improves renal function in AKI perhaps by causing renal vasodilation. When NO synthesis is blocked, testosterone is incapable of improving PCr after I/R. Furthermore, although the known renal vasodilator PGE2 also improves PCr in I/R, although not as effectively as testosterone. These data continue to support the notion that testosterone infusion has therapeutic potential for the treatment of I/R induced AKI in humans. Supported by NIH R01HL66072, P01HL05971 and AHA 14POST18640015.
Abstract 302: SHR Animals Have ADH Induced Over Stimulation On Sodium Transport
Authors: Silva Guillermo B , Juncos Luis I , Garcia Nestor H
Published: July 2021

During hypertension kidney fails to maintain Na balance, leading to increased blood volume and blood pressure. It has been suggested that humoral defects and in the last decade in Na transport disorders have been described in different tubular segments. Our aim was to investigate the interaction between antidiuretic hormone (ADH) and angiotensin II (Ang II) in oxygen consumption (QO2, as a marker of Na transport ) in the loop of Henle , in normotensive and hypertensive animals. To do that we used suspensions of thick ascending limbs of the loop of Henle and and measured QO2, cAMP and superoxide production. We found that In normotensive animals, the basal QO2 was 112 ± 5 nmol O2/min/mg protein. ADH (1 nM) increased QO2 227% compared to baseline values. In the presence of ADH and Ang II (1 nM) initially decreased QO2 with a subsequent recovery (279 ± 17 nmol O2/min/mg protein). ADH increased cAMP levels, whereas Ang II decreased it. In contratst, ADH caused no effect in superoxide levels in thick ascending limbs of normotensive and increased after 3.3 minutes incubation. In hypertensive rats, the QO2 was stimulated by 98% after ADH. In these rats, and Ang II + ADH produced an initial decrease QO2 and a subsequent over-stimulation by ADH (184 % increase , p <0.05 vs normotensive animals) . Unlike what was observed in normotensive animals, Ang II increased early superoxide levels before at 1.7 minutes incubation and reached significant values compared to basal. In addition Losartan blocked the Ang II -induced effects. The superoxide scavenger tempol blocked the increase in Ang II -induced QO2 in both animal models. Taken together these results indicate that in hypertensive animals there is an additive effect between ADH and Ang II in the thick ascending limb of the loop of Henle. Therefore, the abnormal mechanism observed in hypertensive animals could explain the Na positive balance in this model of arterial hypertension.
Abstract 305: Activation of Central Angiotensin II type 2 Receptors Attenuates Neurogenic Hypertension.
Authors: Brouwers Sofie , Wainford Richard D , Smolders Ilse , Dupont Alain G
Published: July 2021

Aim:
The role of the angiotensin II type-2 receptor (AT2R) in hypertension is under debate and the expression can be modulated in different pathological states. In hypertension AT2R are upregulated, therefore we hypothesize that central AT2R stimulation will lower blood pressure in conscious spontaneously hypertensive rats (SHR).

Methods:
SHR were implanted with a radio-telemetry device and an icv cannula connected to a miniosmotic pump delivering saline vehicle, AT2R agonist Compound 21 (C21) (0.002μg/μl/hr) alone or in combination with AT2R antagonist PD123319. MAP was assessed for 21 days: 7 days baseline (saline), 14 days treatment (e.g. C21). To assess the role of the angiotensin II type-1 receptor (AT1R) and NO in these responses, AT1R blocker losartan or NO synthase inhibitor L-NAME were administered centrally with C21. (n=5-7/group).

Results:
Icv C21-infusion blocked the increase in MAP seen in the vehicle group (MAP (mmHg): baseline: vehicle 153±5 vs C21 157±4; day 21 (D21): vehicle 164±5 vs C21 155±5;p<0.05). PD123319 abolished this blood pressure lowering effect (MAP (mmHg): baseline 154±5; D21 163±5;p<0.05). Co-infusion of C21 and losartan did not reinforce the MAP lowering effect seen with C21 alone (MAP (mmHg): baseline 157±2; D21 153±1;p<0.05). Simultaneous L-NAME administration abolished the effects of C21 (MAP (mmHg): baseline 156±4; D21 190±5;p<0.05).

Mechanistically, an improved parasympathetic control of HR was seen in the C21-treated group (change in HR after i.p. propranolol (bpm): vehicle -68.2±2.4 vs C21 -36.3±4.1;p<0.05). Impaired baroreflex sensitivity (BRS) also improved under C21-infusion (BRS (ms/mmHg) D21: vehicle 1.81±0.16 vs C21 3.15±0.07;p<0.05)

Conclusion:
Selective central AT2R stimulation with C21 attenuates hypertension and corrects autonomic dysfunction in SHR. These effects are mediated through a NO-dependent mechanism. In contrast to an enhanced peripheral AT2R effect following AT1R blockade, concomitant central AT1R blockade did not enhance these responses to central AT2R stimulation. These findings suggest activation of the central AT2R represent a possible new therapeutic target for the treatment of neurogenic hypertension.
Abstract 306: Alamandine but not angiotensin-(1-7) produces cardiovascular effects in the Insular Cortex
Authors: Marins Fernanda R , Oliveira Aline C , Qadri Fatimunnisa , Alenina Natalia , Bader Michael , Fontes Marco A , Santos Robson A
Published: July 2021

In the course of experiments aimed to evaluate the immunofluorescence distribution of MrgD receptors we observed the presence of immunoreactivity for the MrgD protein in the Insular Cortex. In order to evaluate the functional significance of this finding, we investigated the cardiovascular effects produced by the endogenous ligand of MrgD, alamandine, in this brain region. Urethane (1.4g/kg) anesthetized rats were instrumented for measurement of MAP, HR and renal sympathetic nerve activity (RSNA). Unilateral microinjection of alamandine (40 pmol/100nl), Angiotensin-(1-7) (40pmol/100nl), Mas/MrgD antagonista D-Pro7-Ang-1-7 (50pmol/100nl), Mas agonist A779 (100 pmol/100nl) or vehicle (0,9% NaCl) were made in different rats (N=4-6 per group) into posterior insular cortex (+1.5mm rostral to the bregma). Microinjection of alamandine in this region produced a long-lasting (> 18 min) increase in MAP (Δ saline= -2±1 vs. alamandine= 12±2 mmHg, p< 0.05) associated to increases in HR (Δ saline= 2±2 vs. alamandine= 35±5 bpm; p< 0.05) and in the amplitude of renal nerve discharges (Δ saline = -2±1 vs. alamandine= 35±5.5 % of the baseline; p< 0.05). Strikingly, an equimolar dose of angiotensin-(1-7) did not produce any change in MAP or HR (Δ MAP=-0.5±0.3 mmHg and +2.7±1.2 bpm, respectively; p> 0.05) and only a slight increase in RSNA (Δ =7.3±3.2 %) . In keeping with this observation the effects of alamandine were not significantly influenced by A-779 (Δ MAP=+13± 2.5 mmHg, Δ HR= +26±3.6 bpm; Δ RSNA = 25± 3.4%) but completely blocked by the Mas/MrgD antagonist D-Pro7-Ang-(1-7) (Δ MAP=+0 ± 1 mmHg Δ HR= +4±2.6 bpm; Δ RSNA = 0.5± 2.2 %). Therefore, we have identified a brain region in which alamandine/MrgD receptors but not Ang-(1-7)/Mas could be involved in the modulation of cardiovascular-related neuronal activity. This observation also suggests that alamandine might possess unique effects unrelated to Ang-(1-7) in the brain.
Abstract 307: Enhancement of Cerebrovascular Relaxation by Angiotensin II Type 2 Receptor Agonist, C21, is Lost in Type 2 Diabetes
Authors: Fouda Abdelrahman Y , Hardigan Trevor , Soliman Sahar , Pillai Bindu , Ergul Adviye , Fagan Susan
Published: July 2021

Background:
Angiotensin type 1 receptor (AT1R) blockers provide vascular protection and improve stroke outcomes in young otherwise healthy animals. These effects are believed to be mediated by the indirect stimulation of AT2R signaling. The AT2R agonist, compound 21 (C21), improves endothelial function in peripheral vascular beds but its effect on cerebral endothelial function remains unknown. It is important to determine the vascular effects of C21 in diabetes, a comorbid condition which is known to worsen stroke outcomes.

Methods:
Endothelium-dependent relaxation was assessed in male Wistar and Type 2 diabetic Goto-Kakizaki (GK) rats (n=3-6) by measuring acetylcholine (ACh, 1 nM - 5 μm) induced dilatory response in basilar arteries. In a subset of experiments C21 dose response curves were generated (0.1 nM - 1 μM) or vessels were pre-incubated with 100 nM C21 ± 1 μM PD123319 (AT2R blocker) for 30 min prior to Ach dose response curves. Area under the curve (AUC) and half maximal effective concentration (EC50 nM) were calculated as indices of total relaxation and receptor sensitivity, respectively. Angiotensin receptors expression was measured by immunoblotting of brain homogenates.

Results:
AT2R agonist C21 dose response curves showed no basilar reactivity in either control or diabetic animals. Pre-incubation with C21 enhanced relaxation to Ach in control animals (vehicle 146.7 ± 3.9 vs C21 pretreatment 229.6 ± 11.6), which was abolished by the blockade of AT2R (176.9 ± 25.5, p=0.007). Similarly, C21 improved sensitivity in control animals (vehicle 110.5 ± 32 vs C21 pretreatment 11.9 ± 2) which was abolished in the presence of PD123319 (93.8 ± 31, p=0.04). Basilar artery relaxation (AUC) was impaired in diabetic GK rats (93.9 ± 1.8%) as compared to controls (146.7 ± 3.9%) and C21 had no effect (98 ± 8.9%) indicating a disease and treatment interaction (p<0.001). Normalized AT1R expression levels were 1 ± 0.04 and 0.98 ± 0.05 in control vs diabetic rats and respective AT2R levels were 1 ± 0.1 and 0.84 ± 0.09.

Conclusion:
C21 improves vascular relaxation in control but not in diabetic rats in an AT2R-dependent manner. Underlying mechanisms blunting response to C21 need to be further investigated and may impact the subsequent development of C21 as a treatment for stroke.
Abstract 308: Nephron Specific Deletion Of Angiotensinogen Modulates Blood Pressure
Authors: Ramkumar Nirupama , Stuart Deborah , Calquin Matias , Wang Shuping , Niimura Fumio , Matsusaka Taiji , Kohan Donald E
Published: July 2021

It is unknown if intrarenal generation of angiotensinogen (AGT) is important in blood pressure (BP) regulation. Previous studies showed that proximal tubule-specific overexpression of AGT increases BP, while proximal tubule-specific deletion of AGT using the KAP promoter-Cre transgene did not alter BP. The latter study may not have completely eliminated nephron AGT production; in addition, BP was only assessed on a normal salt diet. To evaluate this issue in greater detail, we developed mice with inducible nephron-wide AGT deletion. Mice were generated which were hemizygous for the Pax8-rtTA and LC-1 transgenes and homozygous for loxP flanked AGT alleles to achieve nephron-specific AGT disruption after doxycycline induction. Adult Pax8-rtTA/LC-1/floxed AGT mice at 3 months of age were treated with doxycycline 2 mg/ml in drinking water for 11 days and studied 4 weeks after treatment. Blood pressure (recorded via telemetry) and metabolic balance studies were determined during 5 days of normal, high and low Na diets. Compared to controls, AGT knockout (KO) mice demonstrated significantly lower systolic, diastolic, and mean BPs on all three diets (N=4 each group). The BP reduction was most evident on a low Na diet (mean BP 107 ± 2 mmHg in controls and 88 ± 13 mmHg in AGT KO). Plasma renin concentration was higher in the AGT KO mice as compared to controls on all three diets. There were no detectable differences in weight, urine volume, urine osmolality or urine Na excretion between the controls and KO mice on all three diets, however due to variability, small differences in these parameters may not have been detected. Taken together, these data suggest that nephron AGT may contribute to BP regulation and this is most evident during low Na intake.
Abstract 310: 17-β Estradiol Treatment Prevents Angiotensin II-Induced Hypertension in VCD-Treated Menopausal Female Mice, Independent of Renal T Lymphocyte Infiltration
Authors: Pollow Dennis P , Romero-Aleshire Jill , Goldberg Emily , Nikolich-Zugich Janko , Brooks Heddwen L
Published: July 2021

T lymphocytes are required for the development of Angiotensin II (Ang II) hypertension in male mice. Cycling female mice are protected against Ang II hypertension, and inducing ovarian failure (menopause) eliminates this protection. We have previously shown that female Rag-1
-/-
mice with adoptively transferred T cells have significantly reduced renal T cell infiltration compared to males. Therefore, we hypothesized that an increase in renal T cell infiltration underlies the genesis of hypertension in menopausal female mice. 10 week old C57Bl/6 female mice received ip VCD injections for 20 consecutive days to induce ovarian failure. Cyclicity was monitored daily via vaginal cytology. Once in menopause, an osmotic minipump was implanted, releasing Ang II (800ng/kg/min) for 14 days. In a subset of mice, a 17-β estradiol pellet (0.1mg) was implanted subcutaneously. Upon harvest, T cell infiltration was measured via flow cytometry. Baseline blood pressure was similar among all groups. Ang II infusion elicited a significantly greater increase in MAP in menopausal mice compared to cycling control (Ang Δ11±10mmHg vs Meno/Ang Δ32±6, p<0.05), which was prevented by 17-β estradiol replacement (Meno/Ang/E
2
Δ5±2mmHg). Despite elevated MAP, there was no significant increase in renal CD3
+
, CD4
+
or CD8
+
T lymphocyte infiltration in Meno/Ang group vs control. However, 17-β estradiol replacement decreased IL-2 renal mRNA expression (0.45±0.13 fold), and increased IL-10 expression (2.41±0.73 fold) compared to Ang II-treated menopausal mice. Ang II induced glomerular hypertrophy in all groups, independent of hormonal status (Control 2156±54μm
2
vs. Ang 3970±383*μm
2
vs. Meno/Ang 3729±51*μm
2
vs. Meno/E
2
/Ang 3505±71*μm
2
, *p<0.05 vs. control). These results demonstrate that the enhanced hypertensive response to Ang II in VCD-treated menopausal mice results from the loss of estrogen function, and does not require an increase in renal T lymphocyte infiltration. Ang II-induced glomerular hypertrophy occurs independently of blood pressure or hormonal status. The VCD model of ovarian failure is a useful model for investigating the underlying mechanisms of estrogen’s role in blood pressure regulation.
Abstract 320: Gata5 Null Mice: A New Genetic Model Of Low-Renin Salt-Sensitive Hypertension
Authors: Messaoudi Smail , Gutsol Alex , Hébert Richard L , Nemer Mona
Published: July 2021

GATA5, a transcription factor of the GATA family, is expressed in the kidney where its function is unknown. In mice, inactivation of GATA5 leads to a cardiac hypertrophy similar to that observed in hypertension. We hypothesized that GATA5 in the kidney may participate in blood pressure (BP) regulation.

Blood pressure was measured by tail-cuff in 3-5 month old GATA5 null (G5-KO) mice and their Wild-type (Wt) littermates. Systolic BP was higher in G5-KO mice when compared to Wt in both males (143±4 vs 122±3 mm Hg, p<0.001, n=14-15) and females (137±2 vs 117±3 mm Hg, p<0.001, n=11-12). High salt diet (8% NaCl for 6 weeks) further increased BP in G5-KO mice (p<0.05) but not in Wt. Under regular diet, there were no changes in water consumption (Wt: 4.0±0.2 ml/24h; vs KO-G5: 4.1±0.1 ml/24h) and urine excretion (Wt: 1.3±0.1 ml/24h; vs KO-G5: 1.1±0.1 ml/24h). Aldosterone urinary concentration was unchanged (Wt: 16.8±2.0 pmol/24h; vs KO-G5: 16.9±1.2 pmol/24h) as well as urinary and plasmatic electrolytes (Na+, K+, Cl-) concentrations. We determined that GATA5 was mainly expressed in the proximal tubule. Expression of genes coding proteins involved in sodium reabsorption in that segment (or others) was either unchanged (NHE3, NKCC2 and aENAC) or decreased (αNaK-ATPase -15% p<0.05; βENaC -21% p<0.01) in G5-KO mice. Renin expression was also decreased by 40% (p<0.05). In contrast, renal expression of pro-inflammatory genes was increased in G5-KO mice (MCP1 +155% p<0.005, PAI1 +90% p<0.01, RANTES +95% p<0.01) but the number of macrophages (assessed by F4/80 immunostaining) in kidney was not different and Masson’s trichrome staining revealed no fibrosis. In contrast, periodic acid Schiff staining showed glomerular hypercellularity in KO-G5 mice (p<0.05). Older G5-KO mice (10 months) exhibited more severe lesions: focal segmental glomerulosclerosis with mesangial cell proliferation, glomerular basement membrane thickening and accumulation of mesangial extracellular matrix.

In summary, G5-KO mice are characterized by hypertension, salt sensitivity and glomerular lesions. They represent a new genetic model to study low-renin hypertension (which affects up to 25% of the hypertensive population) and for which the underlying mechanisms remain incompletely understood.
Abstract 321: A High-Salt Diet Alters the Composition of Intestinal Microbiota in Mice
Authors: Wilck Nicola , Olesen Scott , Matus Mariana , Balogh Andras , Dechend Ralf , Alm Eric , Muller Dominik N
Published: July 2021

Objective:
High-salt intake is associated with cardiovascular disease and hypertension. A substantial number of patients are sensitive to salt, but environmental factors influencing this phenomenon are poorly understood. The gut microbiome has not been considered in the context of salt and hypertension research to date. It is known to respond to fluctuations in lifestyle and diet, and is increasingly recognized as an important factor which influences host health and disease. Using next generation sequencing methods we aimed to determine the effect of a high-salt diet on gut microbiome composition.

Methods and Results:
Male C57BL6/J mice, 10 weeks of age, were individually housed and either subjected to a purified normal salt (0.5% sodium) or high-salt diet (4% sodium + 1% in drinking water) ad libitum for 14 days. Feces was collected on days 0 and 14 of the diets. DNA was extracted from feces, the V4 region of the 16S rRNA gene amplified with PCR. Samples were multiplexed and sequenced with MiSeq. Reads were quality controlled and operational taxonomic units (OTUs) were called by comparison to the Greengenes database.

The high-salt diet created a distinct gut microbiome composition compared to the normal-salt diet (analysis of Jensen-Shannon divergence). Whereas normal diet’s gut microbiome is composed mostly of OTUs from the Bacteroidetes phylum (70% of reads), high-salt diet causes a shift in relative abundance to other phyla (increased Firmicutes:Bacteroidetes ratio). Moreover, the genus Allobaculum significantly spikes after high-salt feeding. Both phenomena have recently been implicated in obesity studies.

Conclusion:
An increase in dietary sodium chloride alters the gut microbiome composition. Our findings indicate new perspectives on how salt impacts the body.
Abstract 334: Selective Pharmacological Kinin Receptor Activation Restores Postischemic Neovascularisation And Hindlimb Perfusion In Diabetic Mice
Authors: Desposito Dorinne , Potier Louis , Chollet Catherine , Gobeil Fernand , Roussel Ronan , Bouby Nadine , Alhenc-Gelas Francois , Waeckel Ludovic
Published: July 2021

Limb ischemia (LI) is a major complication of several cardiovascular diseases. Hyperglycaemia worsens LI by impairing neovascularisation. Genetic or pharmacological inactivation of the kallikrein-kinin system aggravates LI experimentally while ACE/kininase II inhibition improves its outcome. We assessed whether direct, selective and potent pharmacological activation of kinin receptors, B1 or B2, can have therapeutic effect in mice with LI.

The selective B1 receptor agonist SarLys[Hyp3,Igl5,DPhe8]desArg9-bradykinin (B1-ago) or the selective B2 agonist [Hyp(3),Thi(5),(N)Chg(7),Thi(8)]-bradykinin (B2-ago) were administered by osmotic micropumps (30 nmole/kg.h-1) for 14 days after unilateral femoral artery ligature in mice previously rendered diabetic by streptozotocin. Comparison was made with ligatured, non-agonist treated normoglycaemic (normo) and hyperglycaemic (control-hyper) mice.

Chronic administration of B2-ago had no effect on blood pressure, like B1-ago. B1-ago or B2-ago similarly restored the impaired neovascularisation process in diabetic mice as assessed by microangiography [angiographic score, ischemic/non-ischemic hindlimb ratio (R) 0.99±0.13, 0.60±0.06, 1.09±0.13 and 0.99±0.07 in normo, control-hyper, B1-ago and B2-ago respectively, n=10/group, p<0.01] and by histological capillary density analysis (R: 1.2±0.2, 0.68±0.04, 1.7±0.1, and 1.8±0.1, p<0.01). Both treatments increased blood flow in the ischemic hindfoot measured by laser doppler perfusion imaging (R: 0.62±0.05, 0.47±0.03, 0.76±0.04, 0.69±0.03 in normo, control-hyper, B1-ago and B2-ago respectively, p<0.01).

VEGF content in the ischemic gastrocnemius muscle increased 2 fold (p<0.05) during B1-ago or B2-ago treatment and macrophage infiltration 3 fold (p<0.01). Both treatments increased (0.5 to 1 fold, p<0.05) circulating CD45/CD 11b-positive monocytes and CD34/VEGFR2 endothelium or bone marrow derived progenitor cells but not other bone marrow derived progenitors.

Thus, selective pharmacological activation of either B1 or B2 receptor restores postischemic neovascularisation and tissue perfusion in hyperglycaemic mice. This effect involves mobilisation of macrophages and enhanced VEGF synthesis.
Abstract 341: Cytochrome P450 1b1 Is Essential For The Development Of Aortic Aneurysm In Apoe Knockout Mice
Authors: Thirunavukkarasu Shyamala , Khan Nayaab S , Ghafoor Hafiz U , Jennings Brett L , Mukherjee Kamalika , Estes Anne M , Malik Kafait U
Published: July 2021

Previously we showed that the development of hypertension is dependent on cytochrome P450 (CYP)1B1 activity. This study addressed the role of CYP1B1 in the pathogenesis of angiotensin II (Ang II)-induced aortic aneurysms. Sixteen week old male ApoE-/-/Cyp1b1+/+ and ApoE-/-/Cyp1b1-/- mice were administered Ang II (700 ng/min/Kg) or its vehicle (veh) for one month using mini-osmotic pumps implanted subcutaneously. A separate group of ApoE-/-/Cyp1b1+/+ mice receiving Ang II were injected twice weekly with the selective inhibitor of CYP1B1 2,3',4,5'-tetramethoxystilbene (TMS) (300 μg/Kg) or its vehicle DMSO (i.p.). Ultrasound studies showed that Ang II infusion produced abdominal aortic aneurysms in the ApoE-/-/Cyp1b1+/+ mice that were prevented by simultaneous treatment with TMS or Cyp1b1 gene deletion. Ang II-induced aortic aneurysms were characterized by increased degradation of collagen, elastin and actin; and expression of matrix metalloproteinases MMP2, 9 as well as markers of inflammation including macrophages, and CD3+ T cells, and increased production of reactive oxygen species in the ApoE-/-/Cyp1b1+/+ mice; these changes were minimized by treatment with TMS or Cyp1b1 gene deletion (Table 1). Microarray analysis indicated downregulation (>1.5 fold) of markers of angiogenesis and inflammation including Angiopoeitin 2, P-selectin, platelet derived growth factor receptor, MMP 2, 9 and 12, and CD276 in the ApoE-/-/Cyp1b1-/- mice. These data suggest that Ang II-induced abdominal aortic aneurysms and associated pathophysiological changes in ApoE-/- mice are mediated by CYP1B1 via increased inflammation and oxidative stress.
Abstract 349: Fetal Growth Restriction Is A Risk Of Vascular Remodeling
Authors: Chisaka Toshiyuki , Mogi Masaki , Nakaoka Hirotomo , Kukita Masataka , Kanno Harumi , Tsukuda Kana , Bai Hui-Yu , Iwanami Jun , Higaki Takashi , Ishii Ei-ichi , Horiuchi Masatsugu
Published: July 2021

Objects:
A number of studies suggest that fetal growth restriction (FGR) promotes a risk of cardiovascular disease and metabolic disorders. However, it has not been well assessed whether FGR would be involved in the exaggeration of vascular remodeling. We investigated the effect of FGR on inflammatory vascular remodeling using cuff- induced vascular injury mouse model.

Methods:
Dams (C57BL/6J strain mice) were fed with an isocaloric diet containing 20% protein (normal protein; NP) or 8% protein (low protein; LP) from 10 weeks of ages. At the day of delivery, all dams were returned to the NP diet. After weaning, offspring were fed with the NP diet. Vascular injury was induced by polyethylene cuff placement around the femoral artery in offspring at 10 weeks of age. Neointima formation was evaluated by Elastica van Gieson staining 2 weeks after cuff placement. We assessed the following parameters in the femoral arteries prepared one week after cuff placement. Inflammatory cytokine and NADPH oxidase subunit were assessed by RT-PCR. Superoxide anion production, cell proliferation were evaluated by dihydroethidium staining, proliferating cell nuclear antigen (PCNA) staining respectively. p38 mitogen-activated protein kinase (p38MAPK) phosphorylation were evaluated by immunoblot analysis.

Results:
Birth weight was significantly lower in LP offspring (LPO) compared with NP offspring (NPO); however, LPO showed a similar body weight compared with NPO at 10 weeks of ages. Blood pressure at 12 weeks of age in LPO did not differ from NPO. Neointima formation was more exaggerated in LPO than NPO with enhanced oxidative stress and PCNA index in the injured artery. Expressions of MCP-1, IL-6, IL-1β and TNF-α in the femoral artery were more enhanced in LPO. Moreover, expressions of NADPH oxidase subunits, such as p22phox, p40phox, p47phox, p67phox, gp91phpx, Nox4 and Rac1 in the injured artery were enhanced in LPO than NPO. The phosphorylation level of p38MAPK was more increased in LPO than NPO.

Conclusion:
FGR led to the enhanced vascular remodeling via enhancement of stress responses such as inflammation and oxidative stress. These results suggest that FGR is a risk of vascular remodeling in the later life after birth.
Abstract 352: Evaluation of Structural, Mechanical and Functional Properties in Small Arteries of Spontaneously Hypertensive Rats Before and After the Development of High Blood Pressure.
Authors: Jeuken Rafael M , Rossoni Luciana V
Published: July 2021

Structural, mechanical and functional adjustments occur in small mesenteric arteries (SMA) of hypertensive models. However, the role of these properties to trigger hypertension is unknown. As expected, the systolic blood pressure was higher in adult (A, 6-month old) male SHR as compared to Wistar-Kyoto rats (WKY) (WKYA: 125±1.1 vs SHRA: 187±3.3 mmHg*); however, it was similar in young (Y, 6-week old) SHR as compared to age-matched WKY (WKYY: 117±1.8 vs SHRY: 120±2.1 mmHg). The 3rd order mesenteric arteries were mounted in a pressure myograph to analyze the structural [lumen diameter (L), cross sectional area (CSA), wall/lumen ratio (W/L)] and mechanical properties [β, representing wall stiffness]. Endothelium-dependent relaxation to acetylcholine (ACh, 10-10-10-5 M) or -independent relaxation to sodium nitroprusside (SNP, 10-9-10-4 M) were evaluated in SMA using wire myography. At the passive condition (Ca2+-free solution) and intraluminal pressure of 160 mmHg, the L was lower in SMA of both SHR (WKYY: 294±12.0 vs SHRY: 241±4.3*; WKYA: 353±4.7 vs SHRA: 283±6.2 μm*); while the W/L ratio was higher in SHR as compared to age-matched WKY. CSA was similar between age-matched groups. β value was higher in SHR independently of age (WKYY: 5.8±0.4 vs. SHRY: 7.8±0.4*; WKYA: 4.7±0.1 vs SHRA: 6.7±0.4*). The collagen area evaluated by picrosirius red staining was higher in SMA of SHRA as compared to WKYA (WKYA: 15±2.4 vs SHRA: 26±1.8%*), but it did not change in young rats. ACh-induced maximal relaxation was similar in SMA from young groups (WKYY: 93±3.8 vs SHRY: 92±3.1%); however, in SHRA ACh elicited a biphasic curve inducing contraction at concentrations higher than 10-7M, which was not observed in WKYA. Relaxation to SNP did not change among groups. Reactive oxygen species analyzed by dihydroethidium was higher in SMA of SHRA as compared to WKYA (WKYA: 100±3.7 vs SHRA: 126±10.3% of integrated density*), but did not change in young SMA. Although SMA of SHRY present eutrophic inward remodeling and wall stiffening, it does not present collagen deposition, oxidative stress or endothelial dysfunction as observed in SHRA; suggesting that vascular remodeling and wall stiffness of SMA are not sufficient to trigger hypertension, at least when endothelial function is preserved.
Abstract 405: Novel Signaling Mechanisms by Which Intracellular Angiotensin II Induces Na
+
/HCO
3
-
CotransporterExpression In The Proximal Tubule of The Kidney
Authors: Li Xiao C , Cook Julia L , Hopfer Ulrich , Zhuo Jia L
Published: July 2021

Previous studies have shown that endocrine and/or paracrine angiotensin II (ANG II) plays an important role in the regulation of sodium and bicarbonate reabsorption in the proximal tubule of the kidney. However, it is not known whether intracellular (or intracrine) ANG II also plays a role in these responses in the proximal tubule. The present study tested the hypothesis that overexpression of an intracellular cyan fluorescent fusion protein of ANG II (ECFP/ANG II) in the proximal tubule of the kidney induces the expression of the Na
+
/HCO
3
-
cotransporter via MAPK- and NF-kB signaling pathways. To test the hypothesis, transport-competent mPCTs from wild-type and type 1a ANG II receptor-deficient mice (AT
1a
-KO) were transfected with ECFP/ANG II, and treated with the AT
1
receptor blocker losartan, the MEK1/MEK2 inhibitor U0126, or the NF-κB inhibitor RO 106-9920. In wild-type mPCT cells, the expression of ECFP/ANG II more than doubled total and/or phosphorylated NHE3 antiporter and Na
+
/HCO
3
-
cotransporter proteins (p<0.01). These response were accompanied by more than threefold increases in phospho-ERK 1/2, p65 subunit of NF-κB, and phospho-IKKα/β (Ser 176/180) proteins (p<0.01). Pretreatment of mPCT cells with losartan, U0126, or RO 106-9920 significantly blocked the effects of ECFP/ANG II (p<0.01). Furthermore, the effects of ECFP/ANG II were significantly attenuated in mPCT cells of AT
1a
-KO mice (p<0.01),. In wild-type C57BL/6J mice, adenovirus-mediated overexpression of ECFP/ANG II selectively in the proximal tubule of the kidney, driven by the sodium and glucose cotransporter 2 (sglt2) promoter, significantly increased blood pressure, total and/or phosphorylated NHE3 and Na
+
/HCO
3
-
proteins, and proximal tubular lithium reabsorption (p<0.01). These responses to ECFP/ANG II as observed in C57BL/6J mice were also attenuated in AT
1a
-KO mice (p<0.01). Our results strongly suggest that intracellular ANG II may induce NHE3 and Na
+
/HCO
3
-
expression, and increase proximal tubular sodium and bicarbonate reabsorption via AT
1a
receptor-mediated activation of MAP kinases ERK 1/2 and NF-κB signaling pathways.
Abstract 408: Hyperglycemia Increases the Prorenin Receptor in the Plasma Membrane of Collecting Duct Cells in Rats with Type 1 Diabetes Mellitus
Authors: Prieto Minolfa C , Arita Danielle Y , Bourgeois Camille T , Satou Ryousuke
Published: July 2021

In type 1 diabetes mellitus (T1DM) there is increased prorenin secretion by the principal cells of the collecting duct. Binding of prorenin to prorenin receptor (PRR) on intercalated cells increases its catalytic activity, increases local angiotensin (Ang) II formation, and stimulates intracellular MAPK signaling responsible for inflammation and tissue fibrosis. Thus, changes in the amount of membrane bound PRR may be a key factor in stimulating these pathways. However, it has not been established that activation of PRR in the collecting duct contributes to increased intrarenal Ang II and tubulointerstitial inflammation via stimulation of inflammatory pathways including transforming growth factor-beta (TGF-β). This study tested the hypothesis that hyperglycemia increases the PRR abundance at the plasma membrane (PM) in the collecting duct cells, thus allowing greater capability to be activated by locally produced prorenin. Streptozotocin (STZ; 60 mg/kg; ip single dose) was used to induce T1DM in Sprague-Dawley rats (N=10) and compared to control rats (N=8). After 7-days induction, STZ-rats showed plasma glucose levels of 428±13 vs. 138±9 mg/dL and insulin of 0.05±0.02 vs. 2.4±0.6 ng/mL, compared to control. Although PRR transcript in the renal medulla were not different between groups; PRR localized predominantly on the apical aspects of collecting duct cells in STZ-induced rats; while in controls it was primarily found intracellularlly. These changes were accompanied by greater levels of active renin and Ang II in the urine and increased TGF-β mRNA levels in the renal medulla of STZ-rats (Renin: 186± 34 vs. 6± 3 ng Ang I/mL/h; P<0.01; Ang II: 884± 147 vs. 42± 14 fmol/h; P<0.05; TGF-β: 1.22 ± 0.06 vs. 0.97 ± 0.03 mRNA ratio; P<0.01). To further assess if hyperglycemia induced in vitro PRR trafficking alterations, collecting duct M-1 cells were treated with normal glucose (NG; 1mM glucose + 1 mM mannitol) and high glucose (HG; 4mM) for 5, 60, and 360 min. PRR protein levels were higher in the PM fractions in cells treated with HG, compared to cells treated with NG. Thus, hyperglycemia increases PRR abundance in the PM of the collecting duct and stimulates TGF-β synthesis in the renal medulla which may underlie the development of tubulointerstitial inflammation.