bluuebunny/crossref_metadata_2025 huggingface dataset:
Overexpresion of 20-Hydroxyeicosatetraenoic Acid Synthesis Increases Vascular Tone
Authors: Wang Mong-Heng , Zhang Fan , Nasjletti Alberto , Laniado-Schwartzman Michal
Published: July 2021

P31

The cytochrome P450 (CYP)4A family catalyzes 20-hydroxyeicosatetraenoic acid (20-HETE) synthesis which promotes vasoconstriction. We transfected gracilis arterioles (GA) with an expression plasmid (pcDNA3.1) containing the cDNA of CYP4A1, the low K
m
arachidonic acid ω-hydroxylase, and examined the consequences of increasing intracellular levels of 20-HETE on vascular diameter. GA were isolated from SD rats and incubated with a mixture of pcDNA3.1/CYP4A1 (20μg)or pcDNA3.1 (control plasmid, 20μg) and liposomes (200μg) in Dubecco’s modified Eagle medium with 10% Nu-serum for 18h. Immunoreactive CYP4A protein levels were markedly increased in GA transfected with the pcDNA3.1/CYP4A1 compared to those transfected with empty plasmid. CYP4A1-transfected GA demonstrated a 2-fold increase in 20-HETE synthesis (0.019 ± 0.005 vs 0.009 ± 0.0017 ng/mg/h in vessels transfected with the CYP4A1 and empty plasmid, respectively). Treated GA were mounted on a pressure-myograph and pressurized to 100 mmHg for functional studies. The internal diameter (ID) of GA transfected with pcDNA3.1/CYP4A1 (55 ± 2μm) was exceeded by that of GA transfected with empty plasmid DNA (99 ± 5μm). Acute treatment with an inhibitor of 20-HETE synthesis (DDMS, 30 μM) increased the ID of CYP4A1-transfected GA to 83 ± 7μm but not of GA transfected with empty plasmid DNA (105 ± 5μm). Likewise, acute treatment with 20-HEDE (10μM), a 20-HETE antagonist, increased the ID of CYP4A1-transfected GA to 90 ± 4μm but not of GA transfected with empty plasmid DNA (101 ± 8μm). These results, together with the observation that CYP4A1 expression and 20-HETE synthesis are detected in untreated arterioles, support the view that 20-HETE of vascular origin contributes to vascular tone.
Effect of Antioxidant Therapy on Nitric Oxide Synthase (NOS) Expression in Hypertensive Rats
Authors: Vaziri Nosratola D , Ni Zhenmin , Trnavsky-Hobbs Debra L , Oveisi Fariba
Published: July 2021

P66

Earlier studies have demonstrated evidence for increased reactive oxygen species (ROS) and enhanced nitric oxide synthase (NOS) expression and NO production in spontaneously hypertensive rats (SHR). Given the negative feedback regulation of NOS by NO, we hypothesized that enhanced NO inactivation by ROS may contribute to compensatory upregulation of NOS in SHR. The present study was designed to test this hypothesis. Eight-week old male SHR were treated for three weeks with either a placebo or the potent antioxidant, lazaroid (des-methyltirilazad, 10 mg/kg/day by gastric gavage). A group of age-matched male Wistar Kyoto (WKY) rats served as controls. Tail arterial blood pressure and urinary excretion of NO metabolites (i.e. nitrate and nitrite, NO
x
) were measured. In addition, immunodetectable NOS isotype proteins in the vascular, renal, cardiac and cerebral tissues were measured by Western blot. Compared to the WKY group, the placebo-treated SHR group showed a marked elevation of blood pressure (129±6 vs 198±8 mmHg, P<0.01), a significant increase in urinary NOx excretion (714±82 vs 1344±187 μmol/g creatinine, P<0.01) and a significant upregulation of eNOS (given as relative optical density) in the aorta (27±3 vs 165±15*), kidney (99±3 vs 180±8*) and heart (17±4 vs 126±2*). Likewise, inducible NOS (iNOS) expression was increased in the aorta (27±3 vs 163±15*), kidney (7±3 vs 322±57*)and heart (30±1 vs 80±2*) of the untreated SHR when compared to the WKY controls. In addition, nNOS expression was elevated in the brain (10±1 vs 18±1*) and kidney (12±1 vs 20±2*) of the untreated SHR group. Lazaroid therapy ameliorated HTN (144±4 mmHg, P<0.01, vs untreated SHR group) and mitigated upregulation of eNOS in the aorta (85±13*), kidney (129±8*) and heart (59±10*). Similarly, antioxidant therapy lowered iNOS expression in the aorta (85±13*), kidney (99±15*) and heart (41±3*) of the treated SHR. However, it had no significant effect on renal and brain nNOS expressions (18±2 and 16±2, respectively). These findings support the role of oxidative stress in the genesis and/or maintenance of HTN and compensatory up-regulations of eNOS and iNOS expressions in SHR. *P<0.05
Kallistatin Inhibits Endothelial Cell Proliferation, Migration and Adhesion
in Vitro
and Angiogenesis in the Ischemic Hindlimb of Rats
Authors: Miao Robert Q , Agata Jun , Chao Lee , Chao Julie
Published: July 2021

P76

Kallistatin is a serine proteinase inhibitor (serpin) which has multifunctions including regulation of tissue kallikrein activity, blood pressure, inflammation and neointima hyperplasia. In this study, we investigated the potential role of kallistatin in vascular biology by studying its effects on the proliferation, migration and adhesion of cultured primary human endothelial cells in vitro, and angiogenesis in the ischemic hindlimb of rats. Purified kallistatin significantly inhibits cultured endothelial cell proliferation, migration and adhesion induced by VEGF or bFGF. To further investigate the role of kallistatin in vascular growth in vivo, we prepared adenovirus carrying the human kallistatin gene under the control of the cytomegalovirus promoter/enhancer (Ad.CMV-cHKBP). Expression of recombinant human kallistatin in HEK 293 cells transfected with Ad.CMV-cHKBP was identified by a specific ELISA. The effect of adenovirus-mediated kallistatin gene delivery on angiogenesis was evaluated in a rat model of hindlimb ischemia. Adenovirus carrying the human kallistatin or green fluorescent protein (GFP) gene were injected locally into the ischemic adductor at the time of surgery. Histological and morphometric analysis at 14 days post injection showed that adenovirus-mediated kallistatin gene delivery significantly reduced capillary density in the ischemic muscle as compared to that of control rats injected with GFP. The anti-angiogenic effect of kallistatin was associated with reduced regional blood flow in the ischemic hindlimb measured by microsphere assays. Expression of human kallistatin was identified in the injected muscle and immunoreactive human kallistatin levels were measured in the muscle and in the circulation of rats following kallistatin gene delivery. These results demonstrate a novel role of kallistatin in the inhibition of angiogenesis and in vascular remodeling.
Renal Interstitial ATP Responses to Changes in Arterial Pressure During Alterations in Tubuloglomerular Feedback Activity
Authors: Nishiyama Akira , Majid Dewan Sa , Walker Matthew , Taher Khandaker A , Navar L. Gabriel
Published: July 2021

P90

We have recently demonstrated a direct relationship between autoregulatory related changes in renal vascular resistance (RVR) and changes in renal interstitial ATP levels. To examine further the possible role for extracellular ATP in the regulation of tubuloglomerular feedback (TGF)-mediated autoregulatory adjustments in RVR, experiments were performed in 8 anesthetized dogs to assess interstitial ATP concentrations in response to changes in renal arterial pressure (RAP) during augmented and diminished activity of the TGF mechanism. Using a microdialysis method, interstitial ATP levels were assessed at different levels of RAP before and during intra-arterial administration of acetazolamide (ACZ; 100 μg/kg/min, n=4) which increases solute delivery to the macula densa thus augmenting TGF activity, and after furosemide treatment (10 μg/kg/min, n=4) which inactivates the TGF mechanism. During the control period, stepwise reductions in RAP within the autoregulatory range from ambient pressure (126±4 mmHg) to 100±2 mmHg (step-1: S1) and 76±2 mmHg (step-2: S2) resulted in significant decreases in ATP concentrations from 8.9±0.7 to 6.3±0.6 nM (S1) and 4.0±0.5 nM (S2). ACZ decreased renal blood flow (RBF; -22±6%) and glomerular filtration rate (GFR; -28±4%), and increased RVR (22±2%) and ATP concentrations (7.9±0.9 to 14.3±1.8 nM). During ACZ infusion, the autoregulatory efficiency of RBF and GFR were maintained, and ATP levels were significantly decreased in responses to reductions in RAP (8.8±0.8 nM in S1 and 6.5±0.7 nM in S2). Inhibition of the TGF mechanism by furosemide increased RBF (32±9%) and GFR (17±2%), and decreased RVR (25±6%); ATP levels concentrations decreased from 8.7±1.1 to 5.4±0.9 nM. Furosemide caused marked impairment of RBF and GFR autoregulatory efficiency (by -17±3 and -16±6% in S1 and by -31±5 and -23±7% in S2, respectively). In addition, pressure-induced changes in ATP levels were completely prevented by furosemide (5.3±0.4 nM in S1 and 5.5±0.5 nM in S2). These data support the hypothesis that extracellular ATP contributes to the RVR adjustments that are elicited by changes in activity of the TGF mechanism.
Corin, a Transmembrane Cardiac Serine Protease, as a Pro-Atrial Natriuretic Peptide Convertase
Authors: Yan Wei , Wu Faye , Morser John , Wu Qingyu
Published: July 2021

P92

Atrial natriuretic peptide (ANP) is a cardiac hormone that reduces high blood pressure by promoting salt excretion, decreasing blood volume and relaxing vessel tension. It is implicated in major cardiovascular diseases such as hypertension and congestive heart failure. In cardiomyocytes, ANP is synthesized as a precursor, pro-ANP, that is converted to biologically active ANP by an unknown membrane-associated serine protease. Recently, we cloned a novel cardiac serine protease, corin, that has the predicted structure of a type II transmembrane protein. Northern and in situ hybridization detected corin mRNA in the heart where its expression was most abundant in cardiomyocytes of the atrium. Corin mRNA was also detected in developing kidney and bones. The overall expression pattern of corin mRNA was very similar to that of ANP, leading to our hypothesis that corin is the pro-ANP convertase. To test this hypothesis, we constructed expression vectors for both human corin and pro-ANP. Recombinant corin and pro-ANP were expressed in human 293 cells. Effects of corin on pro-ANP processing was examined by western analysis. The results showed that human corin, but not control proteases prothrombin and hepsin, converted pro-ANP to ANP in the cell-based experiments. To determine sequence specificity of corin-mediated cleavage in pro-ANP, we constructed a mutant pro-ANP R98G in which the predicted cleave site residue Arg98 was replaced with a Gly. In co-transfection experiments, corin processed wild-type pro-ANP but not mutant pro-ANP R98G, indicating that corin-mediated cleavage in pro-ANP is highly sequence specific. We also examined effects of protease inhibitors on processing of pro-ANP by corin. Our results showed that the activity of corin was inhibited by aprotinin, benzamidine and leupeptin but not soybean trypsin inhibitor. Similar effects of these proteases on pro-ANP processing were reported previously. Thus, corin matches all known characteristics of the long-sought pro-ANP convertase. Identification of corin as the pro-ANP convertase suggests a new regulatory mechanism for the ANP-mediated pathway that is important for controlling blood pressure.
cGMP-Mediated Inhibition of cAMP Degradation Stimulates Renin Secretion Without Affecting Renal Hemodynamics.
Authors: Sayago Cecilia M , Beierwaltes William H
Published: July 2021

P100

The stimulatory second messenger for renin is cAMP, which is degraded by phosphodiesterase (PDE)-3. PDE-3 is inhibited by cGMP, while PDE-5 degrades cGMP. We hypothesized that if endogenous cGMP was increased, it could inhibit PDE-3, increasing cAMP, and stimulating renin. We used the selective PDE-5 inhibitor Zaprinast at a dose we determined would not change either blood pressure or renal blood flow (RBF). In inactin-anesthetized rats, renin secretion rate (RSR) was determined by collecting arterial and renal venous blood while measuring RBF before and 75 min after administering 20 mg/kg bw Zaprinast (n=9) ip, or vehicle (n=7). Blood pressure before and after Zaprinast was unchanged at 102 ±2 and 98 ±2 mmHg, respectively, similar to vehicle controls (107 ±3 to 105 ±4 mmHg). RBF was unchanged by either Zaprinast (5.57 ±0.38 to 5.77 ±0.41 ml/min/gkw) or vehicle (6.21 ±0.47 to 6.25 ±0.42 ml/min/gkw). Zaprinast increased RSR 6-fold (from 2.95 ±1.74 to 17.62 ±5.46 ng Ang1/hr/min,
p
<0.024), while vehicle had no effect (4.08 ±2.02 to 3.87 ±1.53 ng Ang1/hr/min). Zaprinast also increased renal cGMP excretion from 12.75 ±1.57 to 18.67 ±1.87
p
mol/min (p<0.003), while cGMP excretion was unchanged by vehicle (13.07 ±1.76 to 12.42 ±2.16
p
mol/min). Thus, inhibition of cGMP degradation by the PDE-5 inhibitor Zaprinast increased endogenous cGMP (as reflected in excretion) and also stimulated renin secretion, despite not significantly changing renal hemodynamics. These data suggest that endogenous cGMP may indirectly regulate renin through its direct effect on cAMP degradation.
A Combination of Hypercholesterolemia and Hypertension Augments an Impairment in Intra-Renal Perfusion Responses
Authors: Rodriguez-Porcel Martin G , Krier James D , Lerman Amir , Romero Juan C , Lerman Lilach O
Published: July 2021

P105

The kidney is a target organ for cardiovascular risk factors, such as atherosclerosis and hypertension (HT), and is particularly susceptible to their combination. Even at an early stage, hypercholesterolemia (HC) and HT are individually associated with impaired renal perfusion responses to challenge with vasodilators. However, the effect of combined HC and HT on renal perfusion remains uncertain. To examine this, regional renal perfusion response to the renal vasodilator acetylcholine (Ach) was quantified in 4 groups of pigs, using electron beam CT, after 12 weeks of either normal (n=6), HC diet (n=6), HT (unilateral renal artery stenosis, n=5), or combined HC and HT (HC+HT, n=6). The HC and HC+HT groups had increased cholesterol levels vs. normal and HT (430±82 and 351±52 vs. 71±6 and 83±4 mg/dl, ANOVA p<0.05, respectively). Mean arterial pressure was significantly elevated in HT and HC+HT vs. normal and HC (132±6 and 127±13 vs. 88±5 and 92±6 mmHg, p<0.05, respectively). The combination of HC and HT was associated with a greater impairment in cortical and papillary perfusion responses than HC or HT alone (Table). Medullary perfusion response was not significantly different among the four groups (Table). These results demonstrate that concurrent HC and HT have a greater detrimental effect on renal perfusion responses than HC or HT alone, and that this effect is regionally heterogeneous. These effects may potentially lead to enhanced renal functional impairment and may play a role in the progression of renal damage in HT and atherosclerosis.
Positive Association Between the Lys198 Asn Polymorphism in the Endothelin-1 and Blood Pressure in Obese Japanese Subjects: Ohasama Study
Authors: Katsuya Tomohiro , Ohkubo Takayoshi , Fu Yuxiao , Tsuji Ichiro , Nagai Kenichi , Asai Takashi , Fukuda Masayuki , Hozawa Atsushi , Higaki Jitsuo , Hisamichi Shigeru , Imai Yutaka , Ogihara Toshio
Published: July 2021

P117

A recent report by Tiret et al. (Hypertension 33, 1999) revealed that a G/T polymorphism with an amino acid substitution (Lys to Asn) at codon 198 in the exon 5 of endothelin 1 gene (ET1) is associated with blood pressure in overweight people using two epidemiological studies, ECTIM and Glasgow Heart Scan Study. They suggested that G/T polymorphism strongly interacted with body mass index (BMI) in the determination of blood pressure levels. To examine the interaction among G/T polymorphism of ET1, BMI and blood pressure, we carried out an association study using a general population. Subjects (n=1,446) were recruited from Ohasama population, which is a cohort in a rural community of northern Japan. The research protocol was approved by the Institutional Review Board of the Tohoku University. DNA was extracted from the buffy coat of the participants using QIAamp DNA Blood Kit (Qiagen Inc.). G/T polymorphism of ET1 was determined by TaqMan PCR method, which is a powerful tool for semiautomatic genotype determination in a large number of samples. The frequency of T198 allele in Japanese (26%) was significantly higher than that in Caucasians (23%). The baseline characteristic (age, BMI, SBP, DBP, antihypertensive treatment) of all subjects was not significantly different according to the genotype of G/T polymorphism. In the obese subjects (≥25kg/m2), however, SBP and DBP were significantly associated with G/T polymorphism. Blood pressure level in the subjects carrying T198 allele was 2.6 mmHg in systolic (p<0.02) and 2.3 mmHg in diastolic (p<0.005) higher than that in those with GG genotype in overweight people. That the same result was obtained from different races suggested that the T198 allele of ET1 is involved in the determination of blood pressure levels in obese subjects.
Heritability of Heart Rate upon Stimulation in Members of Families with History of Hypertension
Authors: Gossard Francis , Pausova Zdenka , Deslauriers Benoit , Kotchen Theodore A , Cowley Allen W , Gaudet Daniel , Tremblay Johanne , Hamet Pavel
Published: July 2021

P139

Objectives:Heart rate (HR) is an independant risk factor for cardiovascular disease and believed to be in part genetically determined. We have studied the heritability of HR in members of large families with history of hypertension (HT). In addition, candidate genes involved in cardiovascular regulation were tested. Methodology:Under study, families of the Saguenay-Lac St-Jean of the province of Quebec showed a higher prevalence of HT in all age groups than the national and provincial population and high degree of kinship. Using impedance plethysmography HR was recorded during posture and mental stress tests. DNA extracted from blood leucocytes was analysed by PCR for the ACE and TNF-α genes. Heritability and linkage were analysed with the FCOR and SIBPAL programs of the SAGE package. Results: HR changed significantly from the resting supine position to standing, sitting, 2 min. and 4 min. into the math test and returned to baseline after 10 min of rest. Heritability (h
2
) estimates are shown in the table below. Indexes of h
2
were significant during math test and the recovery period (*:p<0.05,***:p<0.001). Only the ACE I/D polymorphism was suggestively linked (p=0.03) to HR and only for the post-test period. Conclusions: A significant genetic component of HR was observed only during stimulation by the mental stress test. At the post-test period, a part of the heritable component appeared to be linked to the ACE locus. (Supported by MRC and NIH SCOR program)
Abolition of Hypertension-Induced End-Organ Damage by Anti-Androgen Treatment in Transgenic Rats Harboring the Mouse Ren-2 Gene
Authors: Baltatu Ovidiu , Cayla Cecile , Andreev Dimitrii , Bader Michael
Published: July 2021

P171

The possible involvement of androgen receptors in the development of hypertension and end-organ damage in transgenic rats harbouring the mouse Ren-2 renin gene [TGR(mREN2)27] was studied. Male TGR(mREN2)27 rats were treated with Flutamide (specific nonsteroidal competitive antagonist of the androgen receptor, 30 mg/kg/day) starting at 4 weeks of age. Blood pressure was monitored by telemetry until the establishment of hypertension (12 weeks of age). At the age of 12 weeks, urine was collected for albumin analysis (index of kidney damage). Then the rats were sacrificed and plasma angiotensinogen, renin and testosterone concentration, as well as kidney morphology were studied. Flutamide treatment produced a significant attenuation of the development of hypertension (systolic blood pressure: treated 189.7 ± 3.5 vs. control 222 ± 8 mm Hg). Heart hypertrophy was significantly reduced by the treatment (treated 0.35 ± 0.006 vs. control 0.43 ± 0.03 g/ 100 g b.w.). Urinary albumin excretion was blunted (treated 0.6 ± 0.1 vs. control 24.2 ± 7.7 mg/24 h) and no histological characteristics of end-organ damage were observed in the kidney after treatment. Flutamide treatment reduced plasma renin concentrations (treated 27.7 ± 2.7 vs. control 71.7 ± 28.5 ng/ ml), but not plasma angiotensinogen levels (treated 1.58 ± 0.1 vs. control 1.58 ± 0.1 μg/ ml). Testosterone levels increased 20 fold. Our results indicate that treatment with androgen receptor antagonist protects against end-organ damage and attenuate the hypertension in TGR(mREN2)27 rats.
Spironolactone Prevents Activation of the Intrarenal Renin-Angiotensin System and Increases Survival in (mREN2) 27 Transgenic Rats with Malignant Hypertension.
Authors: Wong Donna L , Chappell Mark C , Ferrario Carlos M , Ganten Detlev , Diz Debra I
Published: July 2021

P172

In transgenic rats [(mRen2)27 TGR+] that overexpress mouse renin, there is a high incidence of malignant hypertension (MH), characterized by high mortality between 8 and 12 weeks of age as a result of stroke, myocardial rupture or renal failure. Spironolactone (SPIRO), an aldosterone antagonist, improves survival in patients with heart failure and in stroke prone rats. To determine the role of aldosterone in MH in TGR+, rats at 5 weeks of age were divided into a treated group which received 50 mg/kg SPIRO per day in powdered food or an untreated group receiving no drug. In the untreated group, MH rats were identified by early death and non-malignant hypertensive (NMH) rats were identified by survival to 14 weeks. SPIRO results in a dramatic increase in survival when compared with rats receiving no treatment. The death rate was 11 of 23 rats in untreated rats compared with 1 of 15 in the SPIRO group (p < 0.01). SPIRO produced an intermediate systolic blood pressure determined by tail cuff compared with untreated MH and NMH animals, but did not lower pressure. Thus, a reduction in pressure is not the primary mechanism by which SPIRO reduces mortality. However, SPIRO prevented the loss of renal concentrating capacity as signified by hypo-osmotic polyuria in MH rats. This was associated with increased urinary excretion of Ang II and Ang-(1-7) in the weeks prior to death in MH rats.

SPIRO has been shown to reduce vascular pathology, and as a result, SPIRO may prevent both the loss of concentrating ability and a subsequent inappropriate activation of the intrarenal renin-angiotensin system. (AHA-NC, HL-51952)
Plasma Endothelin of Sibpairs: Variability, Inheritance, and Linkage to Obesity in Essential Hypertension
Authors: Laffer Cheryl L , Schiffrin Ernesto L , Gavras Haralambos , Elijovich Fernando
Published: July 2021

P178

A polymorphism of the endothelin (ET)-1 gene has been associated with blood pressure (BP) of obese individuals in large population studies. We explored the variability of plasma ET in essential hypertensive sibpairs (n=14 pairs, 13 with two sibs, 1 with three sibs) in relationship to their body mass index (BMI). ET levels were measured on ad libitum Na intake (AL), after a 24 hr Na load (300 mEq iv +160 mEq po, HI) and after 24 hr of Na deprivation (10 mEq po + furosemide 120 mg, LO). BP was 147±3/90±2 mmHg and BMI 35.1±1.4, with 75% of patients exceeding 30 Kg/m
2
. ET was 4.4±0.3, 4.1±0.2, and 4.3±0.3 fmol/ml for AL, HI and LO, respectively, all higher than 20 controls (3.3±0.3, ps <0.04). One way ANOVA disclosed that ET variability within pairs was significantly less than that between pairs. This was true for each diet and for all diets combined, with maximal statistical significance after the fixed Na load (F=18.9, p <0.0001). The sibpair variance of plasma ET(AL) exhibited a negative correlation with BMI (r=-0.51, p<0.01) but did not correlate with the sibpair variance for BMI. In an ANCOVA with family ID as main effect and BMI as the regressor covariate, individual ET(AL) was explained by family ID, independent of BMI (Model: R
2
=0.79, F=3.2, p<0.02; Family ID: p<0.03; BMI: ns). Our data suggest that inheritance plays a major role in determining plasma ET of essential hypertensive patients, while salt-balance has a small additional effect. The concordance of ET levels in sibpairs increases with the magnitude of obesity, but this effect of BMI is explained by family ID in the covariate analysis. These results suggest that there is a link between the inheritance of obesity and ET in hypertension, consistent with observations in population studies.
Differences in Mechanisms Between Weight Reduction Sensitive and Insensitive Blood Pressure Reduction in Obese Subjects
Authors: Masuo Kazuko , Mikami Hiroshi , Ogihara Toshio , Tuck Michael L
Published: July 2021

P180

This study was conducted to clarify the differences in mechanisms between weight reduction (WR) sensitive and insensitive BP reduction, and to evaluate the contribution of family history of obesity (FH) to WR-induced BP reduction. In 61 obese hypertensive men (HT, 28.1±0.9 kg/m2, 35±3 years, 171±6/106±5 mmHg) and 52 obese normotensive men (NT, 27.9±0.6 kg/m2, 34±4 years, 131±5/83±4 mmHg), BMI, BP, fasting plasma norepinephrine (NE), angiotensin II (Ang II), PRA, leptin, insulin were measured every 2 week for 24 weeks with weight loss program (low caloric diet 1000kcal, 7gNaCl + excercise≥1 hr/day). WR and WR sensitive BP reduction were defined as >10% reduction in BMI or mean BP at week 12. 64% of HT and 63% of NT succeeded in WR, and 59% of HT with WR (sensitive vs insensitive P<.05) and 70% of NT with WR (P<.01) were sensitive in BP reduction. When FH+ was defined as at least one parent was obese (BMI>27.0 kg/m2), prevalence of FH+ was higher in 86% of HT and 95% of NT who failed in WR, and higher in 94% of HT and 80% of NT with WR insensitive BP reduction. Only the subjects who succeeded in WR were analyzed in this study. At entry, BP, NE, Ang II, PRA and insulin were higher in HT than in NT, although BMI and leptin were similar. However, the parameters at entry were similar between WR sensitive and insensitive BP reduction in each NT and HT. The decrements (Δ) in BP, NE, Ang II, leptin,insulin were significantly greater in subjects with WR sensitive BP reduction than subjects with WR insensitive BP reduction regardless of BP status during the study, although ΔBMI was similar. Significant decreases in the parameters were noted in earlier period in subjects with WR sensitive BP reduction than in subjects with insensitive BP reduction, and in NT than in HT. In the 4 study groups regardless of BP status or WR induced BP reduction, the decrease in NE preceded BP decline, and the decreases in Ang II, insulin, leptin & PRA followed BP decline with WR. These results suggest that a family history of obesity appears to contribute closely to resistance in weight loss and also to WR insensitive BP reduction. Suppression on sympathetic overactivity is a major mechanism in WR induced BP reduction.
Non-N-Methyl D-Aspartate Receptors Are Involved in the Hypertension of D5 Dopamine Receptor Knockout Mice.
Authors: Bek Martin J , Asico Laureano D , Eisner Gilbert M , Sibley David R , Jose Pedro A
Published: July 2021

P185

Dopamine receptors are important in the regulation of renal and cardiovascular function. Mice with disrupted D5 dopamine receptors develop vasopressin-dependent hypertension. Systolic and diastolic blood pressures (BP) were higher in homozygous, D5-/- (systolic BP 136±2 mmHg, diastolic BP 103±2 mmHg, n=45) and heterozygous, D5+/- (systolic BP 135±4 mmHg, diastolic BP 100±5 mmHg, n=8) compared with wild type mice, D5+/+ (systolic BP 104±1 mmHg, diastolic BP 79±1 mmHg, n=45). The maximum decrease in mean arterial pressure (MAPmax) caused by blockade of V1 vasopressin receptors [1-(β-mercapto-β, β-cyclopentamethylene propionic acid), 2-(O-methyl) tyrosine]-Arg8-vasopressin, 10 μg/kg) was greater in D5-/- mice (MAPmax -14±3%, n=13, P<0.05) than in D5+/+ mice (MAPmax -3±1%, n=8), suggesting that in the D5-/- mice V1 receptors were activated, presumably by a central nervous system (CNS) mechanism since circulating AVP levels were not elevated. α-adrenergic receptors were involved; α-adrenergic blockade with phentolamine decreased MAP to a greater and longer extent in D5-/- (MAPmax -21±3%,n=13) than in D5+/+ mice (MAPmax -12±5%, n=7, P<0.05). In the CNS, V1 receptors are linked to the sympathetic nervous system (SNS) via non-NMDA receptors. To prove a CNS-mediated mechanism of hypertension in D5-/- mice, we studied the effect of 2 non-NMDA antagonists on MAP. CNQX (1 mg/kg), a non-NMDA antagonist that does not cross the blood brain barrier had no effect on MAP in either D5-/- or D5+/+ mice. In contrast, the non-NMDA antagonist GYKI (8 mg/kg),which crosses the blood brain barrier, decreased MAP to a greater extent in D5-/- mice (MAPmax -12±4%, n=9, P<0.05) than in D5+/+ mice (MAPmax -3±1%, n=9). V1 and non-NMDA receptors were linked because the decrease in MAP in D5-/- mice caused by combined V1 and GYKI was similar to those caused by either drug, alone. Therefore, disruption of the D5 receptor produces a CNS-mediated hypertension via the interaction of V1 and non-NMDA receptors with the SNS.
Abstract 119: Central Phospholipase A2, Cyclooxygenase-1, Prostaglandin D Synthase and DP1 Receptor Expression During the Development of Angiotensin II-salt Hypertension
Authors: Asirvatham-Jeyaraj Ninitha , Fink Gregory D
Published: July 2021

Chronic angiotensin II (Ang II) infusion combined with high salt in the diet has been used to study the development of Hypertension (HT). We have found that cyclooxygenase (COX) inhibition during the early stages of Ang II infusion prevented the development of HT and sympathetic hyper-activity in AngII-salt model. It is likely that these changes are mediated through alterations in the levels of COX and related enzymes. Therefore, we hypothesized that enzymes such as phospholipase A2 (PLA2), prostaglandin D synthase (PGDS) and COX-1 may be altered in specific brain regions to promote AngII-salt HT. To test this, adult male Sprague Dawley rats were implanted with radio-telemeters and placed on a 2% NaCl diet. They were infused with Ang II (150 ng/kg/min, sc) or the vehicle after obtaining 3 days of basal recording. Mean arterial pressure was significantly elevated in AngII-treated animals compared to controls. Animals were sacrificed 4 days after Ang-II infusion. The brains were removed, frozen and sectioned. Middle cerebral artery (MCA), paraventricular nucleus (PVN), organum vasculosum lamina terminalis (OVLT), subfornical organ (SFO), rostral ventrolateral medulla (RVLM) and choroid plexus (CP) were dissected and processed for western blotting. Western blot analysis showed a significant up-regulation of PLA2 in the MCA, PGDS in the choroid plexus. However, there was no change in the protein levels of COX in AngII treated rats. Next, we measured the levels of PGDS receptor, DP1 and found up-regulation of the receptor in the PVN. The results indicated that there is alteration in the protein levels of PLA2, PGDS and DP1 during the early stages of HT development in this model. This altered protein expression could be critical in driving the development of AngII-salt HT.
Abstract 124: The Effectiveness of Angiotensin Converting Enzyme Inhibitors, Angiotensin II Receptor blocker, or Combination in Reducing Left Ventricular Hypertrophy in Hypertensive Patients: A Systematic Review
Authors: Njoh Roland F , Njei Basile , Nguyen An Thu
Published: July 2021

Background:
Angiotensin converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) are well established antihypertensive medications. Their role in reducing left ventricular hypertrophy (LVH) over other antihypertensives has also been clearly delineated on previous trials and meta-analysis. However, the difference in LVH reduction between ACEIs, ARBs or their combination is still unknown. Data Sources: The Cochrane Control Trials Register, PUBMED (1970 to April 2012), and hand selected reference list of English-language trials. Study Selection: Fourteen clinical trials comparing ACEI, ARB or both with outcome of interest in hypertensive patients, with duration of at least 6 months and that had minimum 20 patients were found. Data extraction: A predefined data extraction protocol was establish that included study reference, objective, design, population demographics, various interventions, outcomes and study quality.

Results:
Eleven randomized double blinded trials, 2 randomized open label trials and one case control trials were identified. Nine compared ACEI to ARB only and the remaining 5 compared ACEI, ARB with ACEI and ARB. There is high evidence that the use of ACEI or ARB in hypertensive patient with LVH for duration of at least 6 months, results in significant reduction in left ventricular hypertrophy measured by echocardiography or MRI as left ventricular mass (LVM) and or left ventricular mass index (LVMI). There is no significant difference between the use of ACEI or ARB in LVH reduction. When comparing combination therapy of ACEI and ARB to monotherapy of either ACEI or ARB, there is some evidence of further regression in LVH with combination therapy. The difference was more pronounced in diabetics. Limitations: Studies had small sample sizes with varied duration of therapy in diverse clinical settings, using different ACEIs and ARBs.

Conclusion:
The current evidence shows that the use of ACEI or ARB in hypertensive patients with LVH results in reduction in LVH. There is no significant difference in LVH reduction between use of ACEI or ARB. The use of both ACEI and ARB provides additional reduction in LVH especially in diabetics; there is however need for larger studies to better delineate these differences.
Abstract 13: Mineralocorticoid Receptor Blockade does not Result in Arterial Destiffening in Healthy Older Adults
Authors: Christou Demetra D , Yoo Jeung-Ki , Hwang Moon-Hyon , Luttrell Meredith , Kim Han-Kyul , Meade Thomas H , English Mark W
Published: July 2021

Arterial stiffness, an independent predictor of cardiovascular disease, is increased in aging, but the underlying mechanisms are not completely understood. We hypothesized that mineralocorticoid receptor (MR) activation is partly responsible for increased arterial stiffness and that MR blockade would lead to arterial destiffening in healthy older adults. To test this hypothesis, we administered in a randomized, double blind, crossover study, 100 mg of Eplerenone (MR blocker) or placebo once per day for one month with one month washout, in 23 healthy older adults (age, 64±1 years; mean±SE) and assessed arterial stiffness (aortic, arm and leg pulse wave velocity (PWV; doppler flowmeter) and carotid artery compliance, distensibility, beta-stiffness index, augmentation index (high resolution ultrasonography and applanation tonometry). Despite reductions in blood pressure in response to Eplerenone (systolic blood pressure: 127±3 vs. 120±2 mmHg, P=0.01; diastolic blood pressure: 74±1 vs.72±1 mmHg, P=0.02; placebo vs. Eplerenone), arterial stiffness did not change (aortic PWV, 9.2±1.2 vs. 8.9±1.2m/sec, P=0.5; arm PWV, 11.4±0.6 vs. 11.7±0.7 m/sec, P=0.7; leg PWV, 13.4±0.4 vs.12.8±0.5 m/sec, P=0.3; carotid artery compliance, 0.17±0.02 vs. 0.16±0.02 mm
2
/mmHg, P=0.6; distensibility, 12.7±1.6 vs.13.6±1.5 10
-3
kPa
-1
, P=0.6; beta stiffness index, 3.2±0.3 vs. 3.4±0.3, P=0.5; augmentation index, 24.3±2.9 vs. 22.0±2.9 %, P=0.3, placebo vs. Eplerenone). In conclusion, MR blockade does not result in arterial destiffening in healthy older adults despite reductions in blood pressure.
Abstract 133: Effects of Valsartan and Clofibrate on Oxidative Stress and Fatty Acid Metabolism in the Kidney of Puromycin-induced Nephrotic Rats
Authors: Muroya Yoshikazu , Ito Osamu , Rong Rong , Sakata Yoshiko , Takashima Kenta , Ito Daisuke , Cao Peng-Yu , Kohzuki Masahiro
Published: July 2021

Fatty acids (FAs) bound to albumin are overloaded to renal proximal tubules in proteinuria and contribute to tubulointerstitial damage. Angiotensin II receptor blocker (ARB) and fibrate have renal protective effects in proteinuria, however it isn’t clear they have effects on fatty acid metabolism (FAM) in the nephrotic kidney. The study tested effects of valsartan and clofibrate on FAM in the nephrotic kidney. Sprague-Dawley rats were used and nephrotic syndrome was induced by Puromycin Aminonucleoside (PAN; 100 mg/kg, iv). Rats were randomly divided into four groups; (1) control group; (2) PAN group; (3) PAN rat treated with valsartan group (PAN+val; 30mg/kg/day, orally); (4) PAN rat treated with clofibrate group (PAN+clo; 500 mg/kg/day, sc). Rats were killed on the 14th day and urinary 8OHdG, a marker of oxidative stress in the kidney, and NAG, a marker of proximal tubular cell damage, were measured. The protein expression of enzymes in the kidney was analyzed by Western blot and immunohistochemistry. Compared with the control group, in the PAN group 8OHdG and NAG increased to 154% and 903% and Western blot showed the protein levels of medium-chain acyl-CoA dehydrogenase (MCAD), a mitochondrial β-oxidation enzyme, cytochrome P450 (CYP)4A, a microsomal ω-hydroxylase of FAs, and PPARγ coactivator-1α (PGC-1α), a regulator of mitochondrial function, decreased respectively to 55%, 54% and 51% without change of the protein level of PPARα, a nuclear receptor regulating FAM. In the PAN+val group proteinuria, 8OHdG and NAG decreased respectively to 57%, 76% and 35% in comparison with the PAN group. In the PAN+clo group proteinuria and NAG decreased to 58% and 28%, but 8OHdG increased additionally to 142% in comparison with the PAN group. Valsartan and clofibrate ameliorated the decreased protein levels of MCAD and CYP4A, but didn’t ameliorate the expression level of PGC-1α. Immunohistochemistry showed the localization of MCAD, CYP4A and PGC-1α in the proximal tubule and confirmed the results by Western blot. ARB and fibrate reduced proteinuria and proximal tubular damage, and ameriorated the disorder of MCAD and CYP4A in the nephrotic kidney. The different effect on 8OHdG in ARB and fibrate would suggest they have variant influence on oxidative stress in the kidney.
Abstract 140: The Effects of Modest Dietary Salt Reduction on Vascular Function and Blood Pressure in Overweight and Obese Adults
Authors: Dickinson Kacie , Clifton Peter , Keogh Jennifer
Published: July 2021

Short term sodium restriction improves endothelial function as measured by flow-mediated dilatation (FMD), however the longer term effects of a modest reduction in dietary salt intake on vascular endothelial function in overweight and obese persons is unknown. Our objective was to determine the effects of a reduction in dietary sodium to 100mmol Na/day compared with 160mmol Na/day on measures of vascular function, and plasma and urinary nitrate/nitrite concentrations and 24hr ambulatory blood pressure in overweight and obese subjects. In a 6 week randomised cross-over trial of 100 Na mmol/day compared to 160mmol Na/day (achieved by giving sodium tablets) overweight and obese subjects had measurements of flow-mediated dilatation (FMD), 24hr BP, augmentation index (AIx), pulse wave velocity (PWV) and plasma and urinary nitrate/nitrite concentrations at the end of each intervention. Twenty five overweight and obese subjects aged 57±7 years (BMI 31.58±3.93kg/m
2
; SBP 128±11mmHg; DBP 76±5mmHg) completed the intervention. Urinary sodium decreased from 155±58mmol/24hr to 113±45mmol/24hr (p=0.002). Weight and 24hr urinary potassium excretion were not different between interventions (p>0.05) as planned. Following sodium reduction there was a significant improvement in FMD from 3.54±2.83% to 5.63±2.79% (p<0.001). Daytime DBP decreased from 77±6mmHg to 75±7mmHg (p=0.087) with sodium reduction. Endothelium-independent vasodilatation, AIx, PWV and plasma and urinary nitrate/nitrite concentration were not significantly different between treatments (p>0.05). Change in FMD was significantly related to the urinary sodium to creatinine ratio (R = -0.470 P=0.018). Modest sodium reduction has beneficial effects on vascular function in overweight and obese subjects but does not alter nitrate/nitrite concentration in the urine or plasma. Further work is needed to explore the mechanisms by which salt affects vascular function in overweight and obese adults.
Abstract 143: Endoplasmic Reticulum Stress Impairs Vascular Function Through Enhanced Nadph Oxidase Activity and Reduction in Enos Activity
Authors: Galan Maria , Kassan Modar , Trebak Mohamed , Matrougui Khalid
Published: July 2021

Cardiovascular diseases are associated with the induction of endoplasmic reticulum (ER) stress. The induction of ER stress in C57BL/6J and p47phox-/- mice, by the injection of tunicamycin, greatly impaired vascular endothelium-dependent relaxation in C57BL/6J than in p47phox-/- mice. To determine the mechanism by which ER stress impairs endothelium function, we incubated mice primary endothelial cells from coronary arteries (ECs) with tunicamycin (1 μg/mL) for 6 h in the presence or absence of two ER stress inhibitors (Tudca, 500 μg/mL and PBA, 10 mM). Tunicamycin increased the phosphorylation of PERK and eIF2alpha, the expression of CHOP, ATF6 and Bip, Nox2/Nox4 mRNA levels, NADPH oxidase activity and superoxide anion levels. In addition, phosphorylated eNOS and nitrites levels were reduced with tunicamycin. All these events were prevented, at least partially, with the inhibition of ER stress. Tunicamycin treatment or the transfection of ECs with plasmids that express ATF6 or CHOP reduced the luciferase activity of a reporter plasmid containing the eNOS promoter. The ER stress induction reduced ERK1/2 phosphorylation and increased p38 MAPK phosphorylation. The inhibition of p38 MAPK restored the eNOS promoter activity and the eNOS phosphorylation, and reduced Bip but did not affect to ATF6 or CHOP expression.

Conclusion:
ER stress induction impairs endothelial cell eNOS-dependent activity by oxidative stress and p38 MAPK-dependent mechanisms.
Abstract 179: TLR3 Deficiency Attenuates Preeclampsia-Like Symptoms in Mice
Authors: Chatterjee Piyali , Chiasson Valorie L , Kopriva Shelley E , Weaver Laura E , Mitchell Brett M
Published: July 2021

Preeclampsia (PE), diagnosed by hypertension and proteinuria at or after the 20
th
week of gestation, is mediated in part by excessive immune system activation and inflammation. Ligand binding of the double-stranded RNA (dsRNA) receptors RIG-1, MDA-5, and TLR3 leads to innate immune system activation and inflammation. However, whether activation of all three receptors contributes to the development of PE is unknown. In placentas of women with PE there was significantly increased expression of all three dsRNA receptors as well as dsRNA compared to placentas of normotensive women. Poly I:C (a viral dsRNA mimetic) treatment in control mice on days 13, 15, and 17 induced pregnancy-dependent hypertension (P-PIC SBP: 147±5 mmHg vs. P SBP: 100±4 mmHg, p<0.05), endothelial dysfunction, fetal demise and altered immune cell subsets. This was associated with increased placental protein levels of all three dsRNA receptors compared to normal pregnant mice (RIG-1: 47%, MDA-5: 59%, and TLR3: 86%, p<0.05 vs. controls). Splenic levels of the anti-inflammatory immune cells CD4+/CD25+ regulatory T cells (Tregs) and CD11b+/CD14- myeloid-derived suppressor cells (MDSCs) decreased significantly while the pro-inflammatory immune cells CD11b+ monocytes, CD3+/γδ T cells, and CD11c+ dendritic cells were increased significantly in P-PIC compared to P mice. In pregnant, poly I:C-treated TLR3KO mice SBP was decreased significantly compared to P-PIC mice but not fully restored (P-PIC TLR3KO: 110±3 mmHg). P-PIC TLR3KO mice exhibited significantly reduced endothelial dysfunction and fetal demise compared to P-PIC mice, as well as significantly increased splenic CD4+/CD25+ Tregs and CD11b+/CD14- MDSCs and decreased CD11b+ monocytes, CD3+/γδ T cells, and CD11c+ dendritic cells. These results taken together suggest that activation of dsRNA receptors contribute to the development of PE-like symptoms in mice, but TLR3 deficiency alone did not completely prevent PE-like symptoms. Thus, RIG-1 and MDA-5 activation may play a partial role in blood pressure regulation during pregnancy.
Abstract 190: Activation of Angiotensin Type 2 Receptor Alters High-fat Diet-Induced Lipid Metabolism and Rescues Adipocyte Size Increase in Young Male Mice
Authors: Nag Sourashish , Khan Mohammed A , Hussain Tahir
Published: July 2021

Recent studies demonstrated that the genetic deletion of the angiotensin type 2 receptor (AT2R) decreases adipocyte size and controls obesity, a major risk factor for metabolic syndrome. Current study was designed to investigate the effect of pharmacological activation of AT2R on adipocyte size. Male C57BL/6 mice (4-weeks old) were pretreated with the AT2R agonist C21 (0.3 mg/kg, daily i.p.) for 4 days. Thereafter the animals were placed on normal chow diet (ND) or high-fat diet (HFD) with concurrent drug treatment for next 10 days. In 10 days, the HFD significantly increased the body weight (ND:22+0.26 g vs HFD:24+0.40 g), epididymal fat pads weight (ND:0.23±0.03 g vs HFD:0.42±0.03 g), epididymal adipocyte size (ND:1407+176 μm2 vs HFD:2358+96 μm2), plasma free fatty acid (FFA) (ND:0.63+0.04 nmol/μL vs HFD:0.84+0.06 nmol/μL) and triglyceride (TG) (ND:0.31+0.01 nmol/μL vs HFD:0.40+0.03 nmol/μL). The pharmacological activation of AT2R rescued the HFD-induced increase in body weight (22+0.39 g), epididymal fat pads weight (0.30±0.02 g), epididymal adipocyte size (1831+95 μm2), plasma FFA (0.56+0.03 nmol/μL) and TG (0.18+0.02 nmol/μL). On one hand, HFD increased the protein expressions (measured by western blot) of the epididymal white adipose tissue (WAT) lipogenic regulators namely lipoprotein lipase (LPL) (142%), adipose fatty acid binding protein (FABP4) (199%), fatty acid synthase (FASN) (225%), peroxisome proliferator-activated receptor gamma (PPAR-γ) (176%). On the other hand, a differential regulation in the protein expressions of the epididymal WAT lipolytic regulators was observed. The HFD caused decrease in the protein expression of epididymal WAT adipose triglyceride lipase (ATGL) (62%) while increase in hormone-sensitive lipase (HSL) (191%) protein expression. C21 treatment altered all the HFD-induced changes in the protein expressions of LPL (83%), FABP4 (79%), FASN (54%), PPAR-γ (49%), ATGL (167%) and HSL (50%). In conclusion, the pharmacological activation of AT2R alters the HFD-induced lipid metabolism (lipogenesis and lipolysis) and rescues adipocyte size increase. This is the first study suggesting that the pharmacological activation of AT2R may serve as therapeutic strategy for controlling adipocyte size and obesity.
Abstract 192: Intra-Placental Gene Transfer of Human Insulin-Like Growth Factor-1 Reprograms Fetal Predisposition to Obesity in Intra-uterine Growth Restriction
Authors: Omar Khaled R , Jones Helen , Balaji Swathi , Nam Young , Kil Kitcheol , Leung Alice , Keswani Sundeep , Crombleholme Timothy , Habli Mounira
Published: July 2021

We have shown that intra placental adenoviral mediated gene transfer of (Ad hIGF1) corrects birth weight in a new surgical mouse IUGR model. Evidence shows that IUGR offspring are predisposed to increased risk of adult diseases. We hypothesized that intraplacental Ad hIGF1 not only restores birth weight in this IUGR model but prevents adult onset obesity through fetal reprogramming Laparotomy was done at day 18 on time pregnant C57BL/6J mice, divided into 3 groups. Control: Sham operated; IUGR: birth weight <10% for gestational age; Treated: IUGR+IGF1; n= 16. Pups were delivered on day 20, cross fostered to surrogate CD1 mice, sorted by gender at 4 weeks and followed up to 24 weeks. Body weight, fat pad weight, fasting serum leptin and food consumption were measured. Data analyzed by Chi-square or ANOVA Compared to SHAM, IUGR significantly reduced birth weight, restored to normal in IUGR+IGF-1 (1.12± .1vs 0.9± .1 vs 1.09± .1 g, p= .001). At 8 weeks, IUGR achieved mean body weight equivalent to SHAM and IUGR+IGF-1. By week 21, regardless of sex, IUGR significantly increased weight (obesity) compared to sham and IUGR+IGF-1 (fig A). Total fad pad weights were significantly higher in IUGR compared to SHAM but were restored to normal in IUGR+IGF1 (fig B). IUGR significantly increased fasting serum leptin, compared to Sham and restored to normal in IUGR+IGF1 ( .6± .4vs 5.7± 1.1 vs .8± .4 pg/ug, p= .01). No difference in food consumption amongst the groups Intra placental gene transfer of Ad hIGF1 corrects birth weight in IUGR mice model and attenuates the risk of postnatal obesity, This support the concept that in utero reprogramming of fetal predisposition to obesity is a novel approch to treatment of IUGR.