bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 498: Increased Proliferative Cells in the Medullary Thick Ascending Limb of the Loop of Henle in the Dahl Salt-Sensitive Rat
Authors: Yang Chun , Stingo Francesco C , Ahn Kwang Woo , Liu Pengyuan , Vannucci Marina , Laud Purushottam W , Skelton Meredith , Kurth Terry , Liang Mingyu , Cowley Allen W
Published: March 2022

Studies of transcriptome profiles have provided new insights into mechanisms underlying the development of hypertension. Cell type heterogeneity in tissue samples, however, has been a significant hindrance in these studies. We performed a transcriptome analysis in medullary thick ascending limbs (mTALs) of the loop of Henle isolated from Dahl salt-sensitive (SS) rats and salt-insensitive consomic SS.13
BN
rats on either 0.4% or 7 days of 8% NaCl diet (n=4). The mTAL is a nephron segment importantly implicated in the development of hypertension in SS rats. Pathway analysis was performed based on genes differentially expressed between the two rat strains or by a Bayesian model analysis. The Bayesian model analysis was independent of
a priori
determination of differential expression and selected pathways by incorporating biological knowledge and expression profiles. Both analytical approaches identified pathways involving cell proliferation, cell cycle regulation, and cytokine signaling. The proliferative state of mTAL cells was analyzed by immunofluorescent staining of Ki-67 and p-H3. Of approximately 4,000 mTAL cells counted in each individual rat, 2.3% to 4.4% were in a proliferative state (positive for Ki-67 staining) when the rats were on the 0.4% salt diet (not significantly different between SS and SS.13
BN
rats). Exposure to the 8% salt diet for 7 days substantially increased the number of proliferative mTAL cells in both strains. In SS rats on the 8% salt diet, 15.0% of mTAL cells analyzed were in a proliferative state, which was significantly higher than the 10.1% in SS.13
BN
rats (n=7-9, P<0.05). The total number of cells per mTAL section analyzed was not different between the two strains. The number of cells that were in the G2/M phases (positive for p-H3 staining) tended to be higher in SS rats on the 8% salt diet, but the numbers were small in all treatment groups. The study revealed alterations in regulatory pathways in SS rats in a single cell type, leading to the unexpected finding of a greater increase in the number of proliferative mTAL cells in SS rats on a high-salt diet.
Abstract 500: Differential Predictors of Insulin Resistance in Non-Diabetic, Salt-Resistant and Salt-Sensitive Subjects
Authors: Laffer Cheryl L , Elijovich Fernando
Published: March 2022

Normotensive (NT=16) and untreated hypertensive (HT=23) subjects, without diabetes, underwent an inpatient study of salt-sensitivity of blood pressure (24 hr salt loading [HI] with 2L saline and 160 mMol Na diet, and 24 hr salt depletion [LO] with 10 mMol Na diet and furosemide 40 mg x3); and of insulin sensitivity (homeostatic index, SI
HOMA
). A fall of ≥10 mmHg in average systolic BP (noon to 10 pm) from HI to LO, was the cutoff for defining salt-sensitive (SS) vs salt-resistant (SR) subjects. Laboratory data were obtained before HI, and after HI and LO. NT were younger (40±2 vs 46±2 years, p<0.05) and had lower aldosterone (Aldo; 10±1 vs 22±2 ng/dl, p<0.01) than HT. Despite similar BMIs (30±2 vs 34±1 Kg/m
2
), plasma insulin was lower (10±1 vs 28±3 μU/ml, p<0.01) and SI
HOMA
higher (0.61±0.09 vs 0.18±0.02 ml*L/[μU*mmol], p<0.01) in NT than HT. SS prevalence was 37% in NT and 43% in HT. BP fall was not different between NT and HT, within the SS (-13±2 vs -16±2 mmHg) or SR (-1±1 vs -3±1) groups. Differences between SS and SR included greater percentage of Blacks (63 vs 26%), lower PRA (1.0±0.3 vs 1.9±0.4 ngA
I
/ml/hr), higher Aldo-renin ratio (32±6 vs 17±3 ng*dl
-1
/ngAI*ml
-1
*hr
-1
) and lower SI
HOMA
(0.25±0.03 vs 0.43±0.09) in SS (p<0.05 for all). HI suppressed PRA and Aldo, whereas LO stimulated PRA, Aldo and catecholamines (CAT) in both SR and SS. SI
HOMA
of SR was diminished by LO to the level of SS. Univariate correlates of SI
HOMA
in SR were: age (r=-0.31, p<0.02), MAP (r=-0.48, p<0.001), BMI (r=-0.54, p<0.001), triglycerides (r=-0.43, p<0.001), and Aldo (r=-0.42, p<0.001). Those in SS were: age (r=-0.31, p<0.05), MAP (r=-0.38, p<0.01) and CAT (r=-0.32, p<0.03). Multivariate regressions showed that independent predictors of SI
HOMA
in SR were BMI and Aldo (SI
HOMA
=1.35 - 0.025BMI - 0.013Aldo, r
2
=0.50, F=33.5, p<0.0001); whereas those in SS were MAP and CAT (SI
HOMA
=0.80 - 0.0055MAP - 0.0003CAT, r
2
=0.31, F=10.1, p<0.0003). We conclude: 1. SS are more insulin resistant; 2. acute salt-depletion worsens insulin sensitivity of SR; and most importantly, 3. the hormonal predictors of insulin resistance are different in SR vs SS. Our data suggest that insulin sensitivity could be improved by mineralocorticoid blockers in SR, whereas adrenergic antagonists may be more effective in SS.
Abstract 506: Long-term High Salt Intake Involves Reduced Small Conductance Ca2+-activated K+ (SK) Current in Pre-sympathetic Paraventricular Nucleus Neurons and Increased Sympathetic Nerve Activity (SNA)
Authors: Gui Le , LaGrange Lila P , Chapp Andrew , Zhu Jianhua , Chen Qing Hui
Published: March 2022

It is well-documented that elevated sympathetic outflow is an important contributor to salt-sensitive hypertension. Accumulating evidence indicates that high salt (HS) intake is involved in the activation of the sympathetic nervous system. However, the neural mechanisms responsible for HS-induced sympathetic activation are not fully understood. Recently, we reported that hypertension resulting from angiotensin II and HS intake is characterized by reduced small conductance Ca
2+
-activated K
+
(SK) current and increased excitability of RVLM projecting paraventricular nucleus (PVN-RVLM) neurons. Here, we hypothesized that HS intake may involve both reduced SK current in pre-sympathetic PVN neurons and increased neuronal excitability to contribute to the sympathetic activation. First, we determined whether 5 weeks of HS (2% NaCl) intake alters the SK current in PVN-RVLM neurons and whether this change affects the intrinsic excitability. In whole cell voltage-clamp recordings, the amplitude of SK current in neurons from the HS group (13 ± 5 pA, n=6) was significantly (P < 0.05) less than that from normal salt (NS, 0.4% NaCl) controls (63 ± 11 pA, n=6). In whole cell current-clamp recordings, graded current injections evoked graded increases in discharge frequency among neurons from both groups. Maximum discharge evoked by +200 pA current injection in the HS group was 43 ± 4 Hz (n=8), which was significantly greater (P < 0.01) than that of NS controls (22 ± 1 Hz, n=9). The SK channel blocker apamin (100 nM) significantly increased (P < 0.05) discharge in NS controls (47 ± 4 Hz, n=6), but had no effect in HS rats (45 ± 2 Hz, n=5). Next, the contribution of SK channel activity in regulating SNA was assessed by bilateral PVN microinjection of apamin in anesthetized rats with and without HS intake. Respectively, maximum increases in splanchnic SNA and renal SNA by apamin (12.5 pmol) were 319 ± 41% and 277 ± 48% in rats on a NS diet (n=6), contrasted by a much smaller increase of 116 ± 41% (P < 0.01) and 81 ± 28% (P < 0.01) in rats on HS (n=6). Our data indicate that reduced SK current in PVN-RVLM neurons contributes to the increased excitability in neurons from rats on a HS diet, which may be a contributing factor in the sympathetic activation that appears to accompany elevated salt intake.
Abstract 512: Angiotensin-(1-7) Attenuates PDGF-dependent Migration of Vascular Smooth Muscle Cells
Authors: Tallant E. Ann , Carver Kyle A , Gallagher Patricia E
Published: March 2022

Over one million percutaneous coronary intervention (PCI) procedures are performed each year and restenosis, the narrowing of the vessel lumen due to vascular damage, occurs in more than 40% of these patients. Previous studies by our laboratory demonstrated that infusion of angiotensin-(1-7) [Ang-(1-7)], an anti-proliferative peptide hormone of the renin-angiotensin system, attenuated neointimal formation after vascular injury which was associated with reduced vascular smooth muscle cell (VSMC) proliferation. However, prevention of restenosis after PCI requires inhibition of both VSMC proliferation and migration. In this study, the effect of Ang-(1-7) on VSMC migration was investigated to determine whether a decrease in VSMC migration also represents a component of the heptapeptide-induced reduction in neointimal formation. Platelet-derived growth factor (PDGF), a potent stimulus for VSMC migration, increased chemotaxis in a modified Boyden’s chamber; PDGF stimulated chemotaxis 228% over random migration and pre-treatment with Ang-(1-7) reduced the PDGF-mediated migration to 132% over random movement, a reduction of 42.1% (n=6, p<0.05). PDGF also stimulated directional migration in a wounding assay, by 600% over random migration; pre-treatment with Ang-(1-7) reduced directional migration in response to PDGF to 317% of random migration, a 40.4% decrease (n=5, p>0.01). The reduction in PDGF-mediated migration by Ang-(1-7) was associated with a significant decrease in the phosphorylation of tyrosine 1009 on the PDGF beta receptor as well as the src homology 2 phosphatase-2 (SHP-2) and the tyrosine kinase Src, two enzymes which are positive mediators of PDGF-induced migration. Pre-treatment with Ang-(1-7) attenuated the PDGF-dependent increase in the phosphoY1009-PDGF receptor by 60%, phosphoY580-SHP-2 by 56% and phosphoY416-Src by 45% (n=5, p<0.05). These data demonstrate that Ang-(1-7) inhibits VSMC migration to attenuate neointimal formation, which may result from a reduction in the phosphorylation of the PDGF receptor or attenuation of the cellular events resulting from receptor activation. Further, these results suggest that Ang-(1-7) may be administered as a targeted therapeutic to prevent vascular restenosis.
Abstract 522: Limited and Gene-Specific Down-Regulation of PPAR Delta Target Genes by Dominant-Negative PPAR Gamma in Mesenteric Artery.
Authors: Keen Henry L , Ketsawatsomkron Pimonrat , Faraci Frank M , Sigmund Curt D
Published: March 2022

PPARγ is a ligand-activated transcription factor expressed in multiple tissues including the vasculature. Individuals with a mutation in the ligand-binding domain of PPARγ (P467L) are insulin resistant and have early onset hypertension. Targeted expression of P467L PPARγ to smooth muscle of transgenic mice (S-P467L) increased blood pressure, induced aortic dysfunction, and enhanced myogenic tone in the mesenteric artery. To examine the mechanisms underlying these changes, we used the Affymetrix exon array to perform gene expression profiling of mesenteric arteries from S-P467L and non-transgenic (NT) littermates (n =3 for S-P467L, n=4 for NT). Classic PPARγ target genes, as a group, were down-regulated (p<0.001, gene set analysis), consistent with reports that P467L PPARγ acts in a dominant negative manner. We also observed a down-regulation in pyruvate dehydrogenase kinase, isozyme 4 (PDK4, fold change = 0.4, p = 0.01), a known PPARδ target gene. We confirmed that PDK4 was a PPARδ target (fold change = 2.3±0.3, n = 5, Q-PCR) by 6-hr incubation of NT mesenteric arteries with PPARδ specific agonist GW0742 (1 μM). Based on this, we hypothesized that P467L PPARγ was interfering with and down-regulating PPARδ target genes in the mesenteric artery. To examine this, we integrated our expression dataset with a published study (PLoS One. 2011:e16344) which used expression microarrays and chromatin immunoprecipitation/next-generation sequencing (ChIP-Seq) to experimentally identify PPARδ target genes and PPARδ binding sites in a genome-wide manner. Using this target gene list and limiting our analysis to genes expressed in mesenteric arteries (94 genes), we identified 2 additional PPARδ targets that were modestly but significantly down-regulated (p<0.001) in mesenteric artery from S-P467L mice (TIMP4 -40%, CPT1A -22%). Both of these genes also have a PPARγ binding site according to ChIP-Seq (GEO accession,
GSE13511
); suggesting the possibility of interaction between PPARγ and PPARδ in regulation of target gene expression. Thus, our data shows that dominant-negative PPARγ down-regulates only a small subset of PPARδ target genes in mesenteric artery suggesting that P467L PPARγ exhibits a relative selectivity to PPARγ targets instead of global inhibition.
Abstract 523: Sodium Nitrite Therapy Augments Ischemia-Induced Neovascularization and Blood Flow Recovery in Different Models of Hypertension
Authors: Amin Ali , Choi Sookyoung , Osman-Elazeik Y , Badr El-Din N , Kevil C G , Navar G L , Kadowitz P , Trebak M , Matrougui Khalid
Published: March 2022

Background:
Arterial hypertension is a major risk factor that can lead to exacerbation of peripheral vascular disease due, in part, to endothelial dysfunction. Because sodium nitrite (SN) can be converted to nitric oxide (NO), which counteracts endothelial dysfunction, we explored the effect of nitrite on neovascularization following hind-limb ischemia in different models of hypertension (HT).

METHODS:
Chronic infusion of angiotensin-II (Ang-II, 400ng/Kg/min) or N(omega)-nitro-L-arginine-methyl-ester (L-NAME, 0.1g/L) were used for a two week period to induce hypertension. Mice were subjected to femoral artery ligation induced-ischemia in the hind-limb followed by treatment with SN (50mg/L) for 2-weeks.

Results:
SN significantly reduced systolic arterial blood pressure in mice receiving Ang-II and L-NAME, but had no effect in sham animals. After 2 weeks, blood flow and microangiography showed 60% recovery in sham compared to 40% in HT mice. Importantly, sham and HT mice treated with SN had a 100% blood flow recovery associated with normalization in capillary density. The inhibition of xanthine-oxido-reductase (allopurinol) or VEGFR (SU-5416) prevented the neovascularization in HT mice treated with SN. Cyclic GMP (cGMP) content in the hind-limb was significantly increased in mice treated with SN compared to non-treated mice. Nitrite/nitrate content was only increased in the sham group treated with SN. Immunoprecipitation and Western blot analysis revealed an increase in eNOS/Akt/VEGFR phosphorylation in skeletal muscle from mice treated with SN compared to non-treated mice.

Conclusion:
Our findings determine that SN therapy rescues the neovascularization and blood flow recovery in ischemic hind-limb of sham and HT mice likely through the Akt/NO/cGMP and VEGFR pathways.
Abstract 526: A New Perspective on HDL: Potential Navigation of Blood Pressure via Adrenoreceptor Regulation
Authors: Krohn Stephan , Jumar Agnes , Grün Daniel , Lendner Janna , Zakrzewicz Andreas , Ermilov Eugeny , Siegel Günter
Published: March 2022

Introduction:
HDL is known for its anti-atherogenic qualities and serves as an important protective factor against cardiovascular disease. Recent studies suggested that this vasoprotective effect may not merely be based on reverse cholesterol transport. In fact, HDL has been proven to have vasodilatative properties of its own, a significant mechanism we investigated.

Materials and Methods:
Flow-dependent isometric tension, intracellularly recorded membrane potential and cAMP-cGMP were measured in segments of 20 coronaries from heart transplantations.

Results:
Flow-dependent vasodilatation was elevated by HDL administration [50 mg/dL] causing a mean relaxing effect of -0.236 g (Table). Application of phentolamine (10
-7
mol/L) and propranolol (10
-7
mol/L) resulted in a reduction of HDL induced vasorelaxation. This reduction was also flow-dependently progressing as flow increased. Interestingly, simultaneous α- and β-blockade did not follow an additive interaction pattern. The interaction seemed to be flow-dependent as well, with β-receptors contributing more to the combined effect at low flow rates and α-receptors to a greater proportion at high flows.

Discussion:
For the first time, we describe a potential mechanism of HDL-induced vasodilatation. Blood pressure and lipid profile - two independent risk factors of arteriosclerosis - may be linked by multiple HDL effects. We suggest that this vasorelaxation is in part mediated by activation of β-adrenoreceptors and inactivation of α-adrenoreceptors. This may have crucial implications in the clinical management of both hypertension and hyperlipidemia.
Abstract 531: Role of Insulin Resistance in the Altered Vascular Relaxation Mechanisms and Hypertension in Caveolin-1 Deficient Mice
Authors: Pojoga Luminita H , Reslan Ossama M , Adler Gail K , Williams Gordon H , Khalil Raouf A
Published: March 2022

Insulin resistance (IR) and endothelial dysfunction are often associated with hypertension; however, the specific causality and genetic underpinnings of these associations are unclear. Caveolin-1 (cav-1) is a transmembrane anchoring protein and potential modulator of vascular function and insulin sensitivity of the vascular and metabolic pathways. Our recent findings point to a role for cav-1 in IR, endothelial dysfunction and hypertension. In humans, cav-1 gene variants are associated with IR in hypertensive individuals. In mice, cav-1 deficiency leads to changes in endothelial function, IR and blood pressure (BP). To test whether the vascular changes associated with cav-1 deficiency are related to or are independent of IR, we assessed BP, blood glucose and vascular function in WT and cav-1 KO mice treated with placebo or metformin 400 mg/Kg/day for 21 days. BP was greater in cav-1 KO vs WT (140.1±2.1 vs 116.5±1.3 mmHg), and metformin treatment did not change BP in cav-1 KO (140.7±1.4) or WT (112.5±1.6 mmHg). Fasting blood glucose was greater in cav-1 KO vs WT (112±3.9 vs. 83.1±4.4 mg/dl), supporting a link between cav-1 deficiency and IR. Metformin did not change blood glucose levels in cav-1 KO (110.4±4.1) or WT (86.7±8.2 mg/dl). Acetylcholine (ACh)-induced maximal aortic relaxation was greater in cav-1 KO vs WT (85.3±5.7 vs. 17.5±4.4%), and was abolished by endothelium removal or the NOS inhibitor L-NAME, supporting changes in endothelial NO production/signaling. Metformin reduced ACh relaxation in cav-1 KO to 60.7±6.6%, but had no effect in WT. The exogenous NO donor sodium nitroprusside (SNP) produced similar maximal relaxation in cav-1 KO and WT (98.4±1.6 and 98.2±1.1%), but was more potent in cav-1 KO vs WT (pEC50, 8.6 vs 8.1). Metformin reduced SNP relaxation in cav-1 KO (84.9±6.4%) but not in WT, and reversed the enhanced sensitivity to SNP in cav-1 KO mice. The metformin-induced decrease in vascular relaxation and sensitivity to NO in cav-1 KO mice suggests a role for vascular IR in the changes in endothelial function. The lack of effect of metformin on fasting blood glucose in cav-1 KO mice suggests recalcitrant IR of the metabolic pathways. Together, these data support partial independence of vascular function from systemic IR in cav-1 deficiency states.
Abstract 534: Alternative Splicing of Nitric Oxide Receptor Soluble Guanylyl Cyclase in Diseased Human Aortas
Authors: Sharina Iraida , Golunsky Eva , Laing Susan T , Estrera Anthony L , Martin Emil
Published: March 2022

Soluble guanylyl cyclase (sGC) is a key enzyme in the NO/cGMP signaling pathway. sGC plays an important role in cardiovascular homeostasis and its activity is crucial for maintaining vascular plasticity. Diminished sGC expression and activity leads to endothelial dysfunction and increase in vascular stiffness. We have previously demonstrated that alternative splicing of sGC genes produces different sGC splice forms with altered enzymatic and regulatory properties. Thus, we examined the expression of alternatively spliced transcripts in human aortic tissue. We also compared levels of expression of different splice forms for α1 and β1 sGC in normal and diseased human aortic samples. De-identified specimens of aortas (full thickness) were collected from patients with descending thoracic, thoracoabdominal and ascending aortic aneurysms (N=12), and compared with aortic samples from cardiovascular healthy donors (N=10). The expression of different α1 and β1 sGC splice variants was assessed by semi-quantitative RT-PCR analysis. Previously, we have characterized functional properties of splice isoform encoded by α1 Transcript 5 and demonstrated that this splice form is resistant to oxidative protein degradation. By estimating the ratio of α1 sGC canonical transcript and α1 Transcript 5, we demonstrated that the relative expression of Transcript 5 splice isoform is increased in diseased in comparison to normal samples (0.54±0.12 AU in normal vs 0.29±0.2 AU in diseased, p=0.0015). We also found that the expression of α1 Transcripts 3 and 6 is increased, while the expression of β1 sGC splice forms β1Δ68Ω43, β1Δ68 and β1Ω2 is decreased in diseased human aortas. Using cGMP immunoassay we assessed NO-dependent cGMP accumulation in aortic tissue and demonstrated that sGC activity varies in different samples correlating with relative expression of individual sGC transcripts. Our data demonstrate for the first time that α1 and β1 sGC undergo alternative splicing in human aortic tissue and that the diversity and abundance of splice isoforms is different in normal and diseased aortas. Our results suggest that splicing is one of the mechanisms regulating sGC expression in aorta in diseased condition.
Abstract 535: Effects of Short-term Exercise-Training on Aortic Stiffness and Central Blood Pressure in Young-to-Middle Aged Pre- or Grade I Hypertensives.
Authors: Millen Aletta , Woodiwiss Angela , Avidon Ingrid , Norton Gavin
Published: March 2022

Aim:
To assess the effects of 6-weeks of exercise-training and a period of detraining on aortic stiffness and central aortic blood pressure (BP) in young-to-middle-aged pre- and grade I hypertensives.

Methods:
Thirty-five sedentary or recreationally active men and women (30-57years) with untreated pre- or stage I hypertension completed 6-weeks of continuous moderate intensity (Mod Ex)(n=20) or high intensity interval (High Ex)(n=15) exercise-training (at least 3 days/week, on a stationary bike and/or treadmill) and a 3-week detraining period. Carotidfemoral pulse wave velocity (PWV), aortic augmentation index (AIx), central aortic BP (SphygmoCor) and brachial BP were determined before and after exercise-training and after 3-weeks of detraining.

Results:
Peak oxygen consumption increased from 26.5 to 28.7ml.kg-1.min-1 and from 27.0 to 29.3ml.kg-1.min-1 after 6-weeks of Mod or High Ex respectively (p<0.05). Mod Ex decreased brachial systolic (SBP) and diastolic BP from 141±9/93±7mmHg to 132±10/83±13mmHg (p<0.05) and these values returned to hypertensive/prehypertensive levels after detraining (146±8/92±10mmHg). Neither PWV (baseline: 4.79±0.96m/sec; after 6-weeks training: 4.99±1.00m/sec), AIx (Baseline: 25.5±10.0%; after 6-weeks training: 22.1±11.6%), nor aortic pulse pressure were modified by Mod Ex. Although aortic SBP decreased after 6-weeks of Mod Ex (p<0.05) and returned to baseline values after 3-weeks of detraining, these changes were accounted for by decreases in mean arterial pressure. High Ex did not modify brachial or aortic BP, PWV or AIx.

Conclusions:
In young-to-middle-aged pre- or grade I hypertensives, although short-term moderate intensity exercise-training may decrease aortic BP, these effects are not attributed to alterations in the properties of the aorta.
Abstract 609: Hypoxia-inducible Factor (hif) Prolyl Hydroxylation Pathway In Hypertension And Renal End Organ Damage In Doca/salt Hypertension In The Rat
Authors: Dallatu MK , Myung Choi , Newaz Mohammad , Truong Luan , Nwokocha Elizabeth , Agu Ngozi , Ebiogwu Ada , Oyekan Adebayo
Published: March 2022

Kidney disease could result from hypertension and ischemia/hypoxia. Key mediators of cellular adaptation to hypoxia are oxygen-sensitive HIFs which are regulated by prolyl-4-hydroxylase domain (PHD)-containing dioxygenases. However, activation of HIF can be protective as in ischemic death but it can also promote renal fibrosis. Here we tested the hypotheses that HIF-1α expression will be increased concomitant with reduced PHD expression and PHD inhibition will exacerbate hypertension and target organ damage in DOCA/salt hypertension. In DOCA/salt hypertensive rats (DOCA 50 mg/kg s/c for 3 weeks+ 1% NaCl drinking water), HIF-1α expression was increased (2-fold; P<0.01) and PHD2 expression decreased (52+8%; P<0.05). PHD inhibition with DMAG or cobalt chloride which downregulated PHD mRNA and protein expression with no organ or blood pressure effect of their own, markedly attenuated hypertension (154+7 vs 123+7 mmHg; P<0.01), proteinuria (340+64 vs 116+14 mg/day; P<0.01), kidney or left ventricular hypertrophy (0.76+0.02 vs 0.68+0.03; P<0.05) induced by DOCA/1% NaCl treatment. Similarly, there was a marked blunting of tubular interstitial necrosis, fibrinoid changes and glomerular damage (P<0.01) in DOCA/salt hypertensive rats. Accompanying these changes was increased expression of TGFβ (2.5 fold; P<0.01) or KIM-1 (3.85+0.49 vs 2.67+0.83; P<0.01), marker of glomerular injury but reduced expression of nephrin and podocin (4.5 fold; P<0.01), markers of tubular injury in DOCA/salt hypertensive rats. PHD inhibition blunted these effects without affecting PHD2 expression. These data support a role for HIF/PHD pathway DOCA/salt hypertension as well as the protective effects of PHD inhibitors but casts doubt on the involvement of PHD
per se
as a therapeutic target in the hypertensive renal injury following DOCA/salt administration.
Abstract 62: Gender Differences in Salt Sensitivity Approximated from Ambulatory Blood Pressure Monitoring and Mortality
Authors: Bursztyn Michael , Ben-Dov Iddo
Published: March 2022

We analyzed 2168 ambulatory BP monitoring (ABPM) tracings of untreated patients from our clinical service database for the prevalence, associations and outcome of salt sensitivity (SS), as approximated from monitoring indices. SS was considered low (SSL) in patients with both mean arterial pressure (MAP) dipping >10% and 24h heart rate (HR) <70 bpm; high (SSH) in patients with MAP dipping ≤10% and 24h HR ≥70 bpm; and intermediate (SSI) in patients with other combinations of MAP dipping and 24h HR. Associations with demographic and monitoring variables were evaluated by ANOVA, multivariate general linear models and survival analyses. SSH was predicted for 11% (123/1116) of men and 16% (168/1012) of women (χ2 P<0.0001). Diabetes was more common among SSH men 6.5% (8/123) vs. 3.8% (6/168) in women, P=0.004. Positive linear trends (all P<0.05) were noted between SS and body mass index, clinic BP, 24h ambulatory BP, awake and sleep ambulatory HR and awake and sleep ambulatory BP variability. A negative trend existed with HR dipping (P<0.05). Adjustment for multiple variables abolished the linear associations of SS with clinic BP, ambulatory BP variability and HR dipping. Kaplan-Meier analyses revealed increased mortality in association with SS in men but not in women (Figure). With pooled SSL/SSI as reference, adjusted Cox proportional hazards ratios for all-cause mortality were 1.85 (95%CI 1.03-3.35) among SSH men and 1.03 (0.50-2.13) in women. In conclusion, to the extent that ABPM-derived estimation of SS is feasible, analysis of our ABPM database suggests increased mortality in SS men but not in women in whom SS was more common.
Abstract 622: Increased Mitochondrial Oxidative Stress and Activated AMP- Kinase In the Brain Dorsal Medulla of Hypertensive (mRen2)27 Transgenic Rats
Authors: Nautiyal Manisha , Katakam Prasad V , Busija David W , Chappell Mark C , Diz Debra I
Published: March 2022

The deleterious actions of angiotensin (Ang) II are generally thought to be mediated by NADPH oxidase (NOX)-derived reactive oxygen species (ROS) which may stimulate mitochondrial oxidant release leading to impaired energy metabolism. Hypertensive transgenic (mRen2)27 rats (mRen2) exhibit high NOX activity in brain dorsal medullary tissue compared to normotensive Hannover Sprague-Dawley (SD) control rats; however, the extent of mitochondrial involvement is unknown. Therefore, the present study evaluated mitochondrial ROS levels, ATP and mitochondrial content in the brain dorsal medulla of age-matched mRen2 and SD rats. Additional studies assessed AMP-activated kinase (AMPK) activation since altered mitochondrial oxidant and/or energy levels are associated with a stimulated AMPK pathway that is known to be activated in response to depleted cellular energy levels.

Freshly isolated mitochondria from the dorsal medulla of 20 week old male heterozygous mRen2 [systolic blood pressure (SBP): 211 ± 4 mmHg] and SD [SBP: 120 ± 3 mmHg] rats were loaded with the sensitive ROS indicator dihydroethidium (HEt). Basal HEt fluorescence intensity was ∼16% higher in mRen2 as compared to SD rats suggesting higher ROS levels in mitochondria of the hypertensive strain [mRen2: 83 ± 4 vs. SD: 70 ± 4 mean fluorescence intensity; p=0.02, n=3]. Although ATP levels and mitochondrial content were similar between strains, AMPK was significantly activated (phosphorylated AMPK-α and β
1
subunits) in the mRen2 compared to normotensive SD rats [AMPKα- mRen2: 3.5 ± 0.4 arbitary units vs. SD: 1.0 ± 0.2; p = 0.001, n = 5; and AMPKβ
1
- mRen2: 1.6 ± 0.04 arbitary units vs. SD: 1.0 ± 0.2; p = 0.05, n = 3]. The activation of AMPK may contribute to enhanced mitochondrial biogenesis since ATP and mitochondrial content were unchanged, thus representing a compensatory response to increased energy requirements in the hypertensive strain. We conclude that targeting of mitochondrial oxidants and increased AMPK activation may serve as a potential therapy to improve mitochondrial energy metabolism in hypertension.
Abstract 629: Role of Angiotensin-Converting Enzyme 2 in the Regulation Of Resistance Artery Function
Authors: Briet Marie , Touyz Rhian M , Carter Anthony , Gurley Susan , Burns Kevin D
Published: March 2022

Background:
Angiotensin-converting enzyme 2 (ACE2) metabolizes Ang II to Ang-(1-7), which may have a protective role at the level of the cardiovascular system through its action on the Mas receptor. We hypothesized that, in vivo, ACE2 exerts a protective effect on resistance artery function.

METHODS:
Ten to twelve-week old male ACE2 gene knockout (Ace2-/y) and wild type (WT) mice were implanted with a dummy pump (control) or infused with a subpressor doses of angiotensin II (400 ng/kg/min, s.c.) for 7 days (n=6-8). Systolic blood pressure (SBP) was measured by telemetry. Endothelial function and vessel structure were assessed in 2nd order mesenteric arteries by pressurized myography. Endothelial function was studied as the relaxation response to increasing concentrations of acetylcholine (10-9 to 10-4 M) in the presence or absence of Ang-(1-7) (10-7M).

Results:
SBP was not significantly different amongst the four groups. The vasodilatory response to acetylcholine was significantly lower in Ace2-/y mice compared to WT (maximal relaxation in response to acetylcholine, mean ± SEM, Ace2-/y: 85 ± 2.2 %, vs WT: 97 ± 1.3 %, P<0.001). Ang II infusion induced a significant decrease in the vasodilatory response to acetylcholine in WT mice by 25% (P<0.05) and ace2-/y mice by 28% (P<0.05), compared to control mice. In Ace2-/y mice, Ang II-induced endothelial dysfunction was blunted by the presence of Ang-(1-7) in the myograph chamber, an effect not observed in WT mice. No significant difference was observed in vascular remodeling between the four groups.

Conclusion:
These results indicate that genetic absence of ACE2 causes endothelial dysfunction, independent of changes in blood pressure. The data suggest that endogenous ACE2 exerts a protective effect on resistance artery endothelial function, which may be partly mediated by production of Ang-(1-7).
Abstract 631: Cardiomyocyte-specific Cyp4a12a Overexpression Aggravates Maladaptive Cardiac Hypertrophy
Authors: Westphal Christina , Alenina Natalia , Wesser Tim , Spallek Bastian , Konkel Anne , Bader Michael , Müller Dominik N , Schunck Wolf-Hagen
Published: March 2022

Alterations in cytochrome P450 (CYP)-dependent formation of 20-hydroxyeicosatetraenoic acid (20-HETE) are associated with hypertension and end-organ damage. The cause-and-effect relationships are only partially understood and difficult to dissect due to the multiple and partially opposing roles of 20-HETE in different tissues. We established a Cre/loxP-system for tissue-specific overexpression of Cyp4a12a, a murine 20-HETE producing isoform. We used this system to test the hypothesis that enhanced formation of 20-HETE plays a detrimental role in cardiac hypertrophy. Floxed Cyp4a12a mice were crossed with alpha-MHC-Cre mice to generate animals with cardiomyocyte-specific Cyp4a12a overexpression (CYP) and wildtype littermates (WT). RT-PCR and immunohistochemistry confirmed Cyp4a12a overexpression in CYP compared to WT hearts. The animals (n=10-12 per group) were subjected to transverse aortic constriction (TAC). Eight weeks after TAC, the left ventricular mass-to-tibia length ratio (mg/mm) increased to 14.6±2.3 in male WT and to 12.6±2.3 in male CYP mice. Hypertrophy was lower in WT females (11.2±1.4) but not in CYP females (12.3±2.1), compared to their male counterparts. ANP and βMHC expression levels were higher in CYP than WT mice (2.6- and 2.2-fold in males, and 1.9- and 1.8-fold in females). The ejection fraction (%) was more severely impaired in the CYP than WT groups (male WT: 22.3±4.7 vs. CYP: 9.5±3.4; female WT: 21.8±11.7 vs. CYP: 15.5±4.8). Cyp4a12a overexpression also worsened TAC-induced end-diastolic posterior wall thinning (male WT: 1.05±0.17 vs. CYP: 0.80±0.12; female WT: 0.93±0.12 vs. CYP: 0.85±0.11mm), and dilation (male WT: 5.21±0.53 vs. TG: 5.83±0.53; female WT: 4.82±0.56 vs. CYP: 5.39±0.43mm). Moreover, the interventricular septal thickness was clearly reduced in male CYP compared to WT hearts after TAC. The lung weight was markedly higher in male CYP than WT mice (WT: 201.4±90.9 vs. CYP: 485.3±50.7 mg), but not different in female groups. These results demonstrate that cardiomyocyte-specific overexpression of Cyp4a12a/20-HETE aggravates pressure overload-induced maladaptive hypertrophy and promotes the development of dilated cardiomyopathy. The effects were more pronounced in males compared to females.
Abstract 638: Relationship Of Obstructive Sleep Apnea With Endothelial Function, Distribution Of Body Adiposity, Metabolic Profile And Blood Pressure In Obese Individuals
Authors: Fernandes julia , Araujo Luciene , Amorin Nadia , Torres Marcia , Valença Debora , Rodrigues Maria , Nogueira Livia , Carvalho Renata , Soares Elaine , Sanjuliani Antonio F
Published: March 2022

Background:
Obstructive sleep apnea (OSA) is considered an independent risk factor for cardiovascular disease. There is evidence that individuals with OSA may have increased levels of inflammatory mediators, altered metabolic profile and endothelial dysfunction.

Objective:
To evaluate the relation of OSA with endothelial function, anthropometric parameters, body composition, metabolic profile and blood pressure in obese individuals.

Methods:
Cross-sectional study involving 22 obese patients with body mass index >30 and < 40 kg/m
2
, aged between 24 and 54 years. The diagnosis of OSA was performed using the equipment Watch-PAT200
®
. Endothelial function by peripheral arterial tonometry method, using Endo-PAT 2000
®
.

Results:
After the evaluation of apnea hypopnea index (AHI), participants were allocated in two groups according to AHI: OSA group (OSAG; n=11; AHI = 18.4 ± 3.9) and control group (CG; n=11; AHI= 2.6 ± 0.3). The percentage of men in AOSG (82%, n = 9) was greater than in CG (36%, n = 4); p = 0.03. Both groups presented similar (p > 0.05) age (OSAG: 38.7 ± 1.9 vs. CG: 35.3 ± 3.3y), as well as body mass index (OSAG: 33.2 ± 0.8 vs. CG: 33.3 ± 0.7kg/m
2
); % body fat (OSAG: 31.5 ± 1.15 vs. CG: 35.7 ± 0.7kg/m
2
); and waist circumference (OSAG: 106.2 ± 2 vs. CG: 106.8 ± 2.9cm). Participants in OSAG presented higher values of neck circumference (42.3 ± 0.9 vs. 38.9 ± 1.2cm; P=0.03) and glucose (95.8 ± 3.5 vs. 82.5 ±3.1mg/dL; p=0.01). Subjects with and without OSA had similar levels (p>0,05) of total cholesterol (OSAG: 204.7 ± 10.5 vs. CG: 217.2 ± 13.3mg/dL), HDL-cholesterol (OSAG: 48.1 ± 5.3 vs. CG: 49.5 ± 2.9mg/dL), LDL-cholesterol (OSAG: 129.56± 9.5 vs. CG: 138,3 ± 12.1mg/dL), trigycerides (OSAG: 156.1 ± 24.5 vs. GC: 146.8 ± 19.5mg/dL) and diastolic BP (OSAG: 77.8 ± 2.5 vs. CG: 78.6 ± 2.1mmHg). Mean values of systolic BP presented a tendency to be higher in OSAG (127.4 ± 2.8 vs. 120.7±2mmHg; p=0.07). Endothelial function evaluated by reactive hyperemia index was similar in both groups (OSAG: 1.98 ± 0.14 vs. CG: 1.94 ± 0.14; p=0.86).

Conclusions:
The findings of the present study suggest that in obese subjects OSA occurs more frequently in men and is associated with higher values of neck circumference and of serum glucose.
Abstract 640: BMI as Surrogate for Cholesterol to Calculate Coronary Risk and to Decide on Lipid Lowering Medication: Improved Results with Carotid Total Plaque Area.
Authors: Romanens Michel , García Néor H , Perez Hernan A , Spence J. David , Armando Luis J
Published: March 2022

Background:
The Framingham risk calculator (FRAM) offers the possibility to use the body-mass-index (FRAMb) instead of total and HDL cholesterol (FRAMc). TPA, total plaque area of carotid arteries, may additionally serve to correct for inaccuracies due to unknown cholesterol measurements (FRAMb-TPA;FRAMc-TPA).

Material and Methods:
Participants were recruited from a free checkup program offered by the Swiss Vascular Risk Foundation and included healthy subjects aged > 45 years from the ongoing Cordicare II Study. Predictive risk was compared using the FRAM, FRAMb-TPA and FRAMc-TPA using linear regression models, kappa statistics and areas under the curve analysis (ROC).

Results:
Of 1,000 participants, 47% were females, mean age 60±9 years. 3.3% had Diabetes Mellitus type II, 11% were smokers, and 18% had family history of premature coronary disease. Mean systolic blood pressure was 134±15 mmHg and total cholesterol, HDL-cholesterol, LDL-cholesterol and triglycerides were 5.7±1.1, 1.6±0.4, and 3.5±0.9 and 1.4±0.7 mmol/l respectively. Mean body mass index was 26±4 kg/m2 and total plaque area was 51±51 mm2. Linear regression between FRAMc and FRAMb ten-year coronary risk showed an R2 = 0.89 (p<0.0001) and a Kappa coefficient of 0.72 (p<0.0001). This correlation was further enhanced when comparing FRAMc-TPA to FRAMb-TPA (R2 = 0.94, p<0.0001, wKappa 0.85, p 20% was assessed by ROC analysis and showed an area under the curve (AUC) of 0.98 (95% CI = 0.98 - 0.99, p<0.0001). FRAMb-TPA showing a risk of > 10% had a sensitivity and specificity of 92% and 56% (accuracy 75%) with the highest Youden’s Index, respectively, for the indication to lower LDL cholesterol according to the NCEP III guidelines and a risk assessment defined by FRAMc+TPA.

Conclusion:
When using the FRAM coronary risk function that uses BMI instead of total and HDL cholesterol and results from carotid plaque imaging, we observed a very high correlation, agreement and accuracy of this new method. Within this diagnostic setting, cholesterol profiles can be replaced by BMI without a relevant loss in coronary risk stratification. The indication for a lipid lowering medication defined by FRAMb-TPA is highly sensitive and moderately specific for a coronary risk cutoff of 10% or more.
Abstract 645: Aerobic Vs. Resistance Exercise Training In Ovariectomized Hypertensive Rats: Cardiovascular And Oxidative Stress Evaluations
Authors: Palma Renata K , Brito Janaina O , Sanches Iris C , Conti Filipe F , Dias Daniele S , Barboza Catarina A , Llesuy Susana , Irigoyen Maria C , De Angelis Katia
Published: March 2022

Hypertension becomes more prevalent in menopause women. Aerobic exercise has been indicated as a nonpharmacological treatment for hypertension, however the benefits of resistance exercise are not well know. The purpose of the present study was to investigate the effects of aerobic or resistance exercise training on cardiovascular autonomic control and oxidative stress profile in ovariectomized hypertensive rats. Female spontaneously hypertensive rats (SHR) were divided into 4 groups (n=8 each): sedentary (HS), sedentary ovariectomized(HSO), aerobic trained ovariectomized (HATO) and resistance trained ovoriectomized (HRTO). The moderate intensity aerobic training (AT) was performed on a treadmill (8 weeks) and the moderate intensity resistance exercise training (RT) was performed on a vertical ladder with weights attached to the rat tail (8 weeks). Arterial pressure (AP) and heart rate (HR) were directly recorded and baroreflex sensitivity was evaluated by bradycardic (BR) and tachycardic responses (TR). Oxidative stress was evaluated in cardiac tissue by chemiluminescence, the ratio of glutathione reductase/glutathione oxidized (GSSG-GSH) and superoxide dismutase (SOD) and glutathione peroxidase (GPx) antioxidant enzyme activities. The exercise training induced a reduction in mean AP in trained groups compared to sedentary groups. HR was similar between groups. The AT increased TR in relation to other groups (HATO:-2.74±0.15 vs. HRTO: -1.42±0.2, HSO: -1.4±0.17 e HS -1.91±0.2 bpm/mmHg).However, BR was improved in both HATO (-1.38±0.07 bpm/mmHg) and HRTO (-1.34±0.05 bpm/mmHg) in relation to HS and HSO groups (-1.12±0.1 and -1.01±0.09 bpm/mmHg). Lipid peroxidation was reduced in trained groups in relation to sedentary groups (HRTO: 3538±168 and HATO: 4485±310 vs. HSO: 6514±547 and HS: 6661±566 cps/mg prot). The ratio GSSG-GSH did not differ between groups, however GSSG was higher in HATO group as compared to other groups (HATO: 346±14.5 vs. HRTO: 260±12, HSO:271±12, HS:234±11 μmol/g tissue) and GSH was lower in HRTO group as compared to HATO (HRTO:19±2 vs. HATO: 26±0.7 μmol/g tissue). SOD increased in HRTO in relation to sedentary groups (HRTO: 16.86±0.56 vs. HS:11.47±0.41, HSO: 11.17±0.41 USOD/mg prot) and GPx was higher in HRTO in relation to HSO (HRTO: 60±2.8 vs. HSO: 38.5±1.67 nmol/min/mg prot). In conclusion, aerobic or resistance exercise training induced a reduction in AP, associated with attenuation of baroreflex dysfunction and improvement in oxidative profile in cardiac tissue in ovariectomized hypertensive rats, suggesting a positive role of these nonpharmacological approachs in the management of cardiovascular risk in hypertension after hormones deprivation. Financial Support: FAPESP(2011/16441-0, 2011/15828-9,2010/17188-4)
Abstract 65: Cyclooxygenase-2 is a Source of Oxidative Stress in Small Arteries From Patients With Essential Hypertension or Pheochromocytoma
Authors: Virdis Agostino , Duranti Emiliano , Colucci Rocchina , Bacca Alessandra , Materazzi Gabriele , Blandizzi Corrado , Bernini Giampaolo , Taddei Stefano
Published: March 2022

Essential hypertensive patients (EH) shows a reduced NO availability secondary to reactive oxygen species (ROS) generation. Cyclooxygenase (COX) is a source of ROS. An impaired endothelial function in patients with pheochromocytoma (Pheo) was also described. In this study we assessed the role of COX-1 or COX-2 as determinants of endothelial dysfunction in isolated small resistance arteries taken from EH (n=7, age 49.0±14), Pheo patients (n=7, age 47.1±17) vs control subjects (NT, n=7, age 48.1±9) during a surgical laparoscopic procedure. Small arteries were dissected and investigated on a pressurized micromyograph. Endothelium-dependent vasodilation (VD) was assessed by acetylcholine infusion (Ach, 0.001-100 μM), which was repeated under the NO synthase inhibitor L-NAME (100μM), SC-560 (1 μM, COX-1 inhibitor) or DuP 697 (1 μM, COX-2 inhibitor). Vascular ROS generation was measured by fluorescent dihydroethidium (DHE). EH and Pheo showed elevated BP levels (153/100 and 150/96 mmHg, respectively) vs NT (120/81 mmHg). In NT, maximal VD to ACh (95.1±1.8%) was blunted by L-NAME (61.2±3.4%; inhibitory effect: 33.9±2.1%; P<0.001), and unmodified by SC-560 (94.0±1.1%) or DuP (94.9±0.8%). In EH, VD to ACh was blunted vs NT (58.8±2.5%; P<0.001), resistant to L-NAME (56.2±1.8%; 2.6±0.7% inhibition), not affected by SC-560 (56.9±0.9%) but enhanced (P<0.01) by DuP (80.2±2.1%), which also restored the inhibition of L-NAME on ACh (51.7±1.7%; 28.5±3.7% inhibition). Similarly, in Pheo, VD to ACh was blunted vs NT (60.2±2.6%; P<0.001), slightly sensitive to L-NAME (52.7±2.3%; 7.6±2.9% inhibition; P<0.001 vs NT), not affected by SC-560 (53.9±0.9%) but potentiated (P<0.01) by DuP (78.6±2.2%), which also restored the inhibitory effect of L-NAME on ACh (54.8±2.1%; 23.9±1.7% inhibition). DHE analysis revealed an increased ROS production in EH (stained area: 23±4%) and Pheo (26.5±5%) vs NT (9.2±2%). In both EH and Pheo, ROS excess was attenuated (P<0.01) by incubation with COX-2 inhibitor (EH: 13±3%; Pheo: 14±4%), being unaffected by COX-1 inhibitor (EH: 21.5±2%; Pheo: 25.2±3.5%). In small resistance vessels from EH and Pheo patients, COX-2 participates on reducing NO availability. COX-2 might represent a main source of ROS generation in both clinical conditions.
Abstract 651: Genetic Mapping Of Traits And Transcriptome In The Lyon Hypertensive Rat
Authors: Ma MC John , Wang Jinkai , Mennie Amanda , Pettus Janette , Xing Yi , Kwitek Anne E
Published: March 2022

The metabolic syndrome (MetS) is characterized by obesity, dyslipidemia, hypertension, and insulin resistance and is a major risk factor for cardiovascular disease. Using the Lyon Hypertensive and Lyon Normotensive rats as models of the metabolic syndrome, we aim to determine both physiological and transcriptional regulation underlying the syndrome. To identify genetic loci influencing phenotypes underlying MetS, an F2 intercross between LH and LN with 150 offspring was studied to identify physiological quantitative trait loci (pQTL) contributing to plasma lipid levels, blood pressure, and body weight/adiposity. We performed RNA-seq in livers from 36 selected rats from the intercross to identify the mapping of gene expression, or expression (e)QTL. Linkage analyses identified pQTL and eQTL with significant logarithm of odds (lod) scores, whose genome-wide significance was determined by permutation testing. We identified 17 pQTL on 5 rat chromosomes and 75 on 16 chromosomes. It has been determined that LH chromosome 17 contributes to multiple features of MetS; furthermore, an eQTL on rat chromosome 17 was identified that regulates the expression of multiple genes in
trans,
meaning the regulated gene falls outside the QTL interval or on another chromosome. We hypothesize these genes share a common transcriptional regulator which is affected by genetic variation on chromosome 17. eQTLs are likely to influence precursor pathways and cofactors of the metabolic syndrome. Identifying these in the LH rat could lead to translational studies to determine their role in the human MetS.