bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 196: Involvement of Peroxynitrite Formation in Angiotensin II Induced Changes in Na+K+ATPase Activity in HK2 Cells
Authors: Maiti Arpan K , Islam Mohammed T , Satou Ryosuke , Majid Dewan S
Published: July 2021

Angiotensin II (AngII) induces both superoxide (O
2
-
) and nitric oxide (NO) generation forming peroxynitrite (ONOO
-
) in biological systems. To determine the role of ONOO
-
in AngII induced sodium excretory responses, we examined Na
+
K
+
ATPase (NKA) activity in cultured HK2 cells (human kidney proximal tubule cell line) incubated for 30 min with a wide range (10 pM to 200 μM) of AngII concentrations (conc) in the presence or absence of a ONOO
-
scavenger, mercapto-ethyl-guanadine (MEG; 200μM). Post incubation HK2 cellular membrane fractions were used for measurement of NKA activity via colorimetric assay capable of detecting inorganic phosphate (Pi). Baseline value of NKA activity in these HK2 cells was measured as 10.3 ±0.7 μmoles of Pi liberated/mg protein/hr (n=12). AngII exerts dose-dependent differential effects on NKA activity. Compared to the baseline value, NKA activity was increased at lower conc (13.7±1.3% at 10 pM to 19.6±1.5% at 100nM) and decreased at higher conc (-6.0±0.8% at 1 μM to -38±2.1% at 200 μM ) without any significant effect at 500 nM conc (-1.2±0.6%) of AngII. Interestingly, MEG treatment markedly attenuated these AngII induced changes in NKA activity, both at lower conc (activity increased only to 7.8±0.67% at 10 pM and to 8.9±0.57% at 100nM; an average reduction of 33.2±2.4% in stimulatory effects) and at higher conc (activity decreased to -3.0±0.7% at 1 μM and to -20±0.57% at 200 μM; an average reduction of 54.4±4.1% in inhibitory effects). Co-incubation with O
2
-
scavenger, tempol (1 mM) or NO synthase inhibitor, nitro-L-arginine methyl ester (100 μM) did not alter these AngII induced responses in HK2 cells indicating that neither O
2
-
, nor NO, was directly involved in mediating these responses. AT
1
receptor (AT
1
R) blocker, losartan (10μM) treatment prevented these AngII induced changes on NKA activity confirming the involvement of AT
1
R signaling in these responses. These findings demonstrate a direct contributory role for concomitant ONOO
-
generation in mediating AngII induced changes in NKA activity in the proximal tubular cells. These data also suggest a reno-protective role for ONOO
-
in minimizing sodium retaining action of AngII by the renal tubules, particularly in the conditions associated with enhanced renin-angiotensin system.
Abstract 201: Direct but not Indirect Activation of Sympathetic Ganglia Leads to Higher Neuronal Activation in Normotensive Than Deoxycorticosterone-salt Hypertensive Rats
Authors: Shah Amit H , Hammond Bradley D , Fink Gregory D , Kreulen David L
Published: July 2021

Sympathetic activity is chronically elevated in hypertensive human patients and in many animal models of hypertension, including the deoxycorticosterone (DOCA)-salt rat model. Sympathetic ganglia receive signals from the central nervous system and relay them to blood vessels and peripheral organs. How sympathetic ganglia respond to activation signals differently in hypertension is not fully understood. We examined how direct and indirect activators of sympathetic ganglia would influence neuronal activation. 2-deoxy-D-glucose (2-DG) is a glucose analog that causes hypoglycemia leading to centrally-mediated, indirect activation of celiac ganglia, a prevertebral sympathetic ganglion. Nicotine directly activates sympathetic ganglia by acting on cholinergic receptors found on most sympathetic neurons. Acute neuronal activation was examined by measuring c-fos immunoreactivity (ir). We hypothesized that since there is higher chronic sympathetic activity in DOCA-salt hypertensive than normotensive rats, both direct and indirect acute activators will induce higher c-fos expression in sympathetic ganglia of normotensive than hypertensive rats. Maximal c-fos expression for 2-DG (800mg/kg i.p.) and nicotine (2mg/kg s.c.) treatments was observed 2hrs post-treatment and for all following experiments, celiac ganglia were dissected and fixed 2hrs post-treatment. Following nicotine treatment, c-fos expression was significantly higher in celiac ganglia of normotensive (25.5 ± 9.7 c-fos ir neurons/m^2) than hypertensive (12.0 ± 4.8 c-fos ir neurons/m^2) rats. However, following 2-DG treatment, c-fos expression was similar in celiac ganglia of normotensive (49.1 ± 17.6 c-fos ir neurons/m^2) and hypertensive (49.4 ± 16.0 c-fos ir neurons/m^2). In contrast with our hypothesis, only the direct but not the indirect activation of sympathetic ganglia induced higher sympathetic neuronal activation in normotensive than hypertensive rats. Thus, a centrally-mediated metabolic stimulus does not activate pathways to sympathetic ganglia differentially in normotension versus hypertension. However, direct ganglionic stimulation leads to greater neuronal activation in normotensive than hypertensive ganglia.
Abstract 23: Increasing Leptin Sensitivity in Proopiomelanocortin Neurons Does not Sensitize the Cardiovascular System to Leptin
Authors: Belin de Chantemele Eric J , Bence Kendra K , Hill Lisa K
Published: July 2021

Leptin-mediated control of metabolic function requires activation of the proopiomelanocortin (POMC) neurons in the hypothalamus. Whether POMC neurons also control the cardiovascular effects of leptin still remain to be determined. In order to test the hypothesis that POMC neurons regulate leptin-mediated cardiovascular control, protein tyrosine phosphatase 1B (PTP1B), the molecular restrain of the leptin signaling pathway was deleted in the whole animal (PTP1BKO/WT) or specifically in POMC neurons (PTP1BPOMC/flox) of mice on the C57Bl/6 background using the Cre-Lox technique. PTP1B deletion in POMC neurons recapitulates the protective effects of the total KO on the control of body weight and insulin sensitivity. Conscious blood pressure (BP) measurements (telemetry) revealed that neither baseline (PTP1BWT: 103±4 vs. PTP1BKO: 104±7, PTP1Bflox: 112±3 vs. PTP1BPOMC: 117±6 mmHg) nor BP response to chronic leptin infusion (PTP1BWT: 105±6 vs. PTP1BKO: 107±5, PTP1Bflox: 119±3 vs. PTP1BPOMC: 118±3 mmHg) or cage switch stress were affected by the deletion of PTP1B in PTP1BKO and PTP1BPOMC. Sympathetic tone, assessed by measuring the drop in BP in response to ganglionic blockade was increased in PTP1BKO but not in PTP1BPOMC. Vascular adrenergic tone, an index of chronic sympatho-activation inversely correlated to the level of sympathetic activity was measured in isolated aortic rings via wire myography. Aortic rings from PTP1BKO mice exhibited a reduced adrenergic tone (PTP1BWT: 95±7 vs. PTP1BKO: 46±6% of KCl, p<0.05), whereas PTP1BPOMC presented an increased vascular constriction (PTP1Bflox: 85±79 vs. PTP1BPOMC: 112±13% of KCl, p<0.05) non-specific to the adrenergic response. However, the reduction in vascular adrenergic tone induced by chronic leptin infusion was preserved in PTP1BPOMC mice. These data suggest that POMC neurons do not regulate basal sympathetic tone towards the vasculature. These data also highlight the key role of POMC neurons in the control of metabolic function but minimalize their role in the regulation of cardiovascular effects of leptin.
Abstract 234: Plasma Renin-Independent Generation of Angiotensin II and its Role in the Supine Hypertension of Autonomic Failure
Authors: Arnold Amy C , Okamoto Luis E , Shibao Cyndya , Gamboa Alfredo , Raj Satish R , Robertson David , Biaggioni Italo
Published: July 2021

At least 50% of primary autonomic failure [AF] patients exhibit supine hypertension, despite profound impairments in sympathetic activity. Plasma renin activity is often undetectable in AF suggesting renin mechanisms are not involved in the hypertension. However, since aldosterone levels are preserved we examined the status and contribution of the renin-angiotensin [Ang] system in AF. Supine plasma Ang peptide levels were measured in hypertensive AF patients [AF-HT, n=18], normotensive patients [AF-NT, n=11] and matched healthy subjects [n=10]. Despite suppressed renin activity, total renin concentration was intact in AF [16 ± 5 AF-HT vs 11 ± 4 AF-NT vs 7 ± 1 pg/mL healthy; p=0.29] and plasma prorenin was selectively elevated in hypertensive patients [2.0 ± 0.5 AF-HT vs 0.7 ± 0.1 AF-NT vs 0.6 ± 0.1 ng/mL healthy; p < 0.05]. While levels of Ang I were similar among groups, Ang II was paradoxically elevated [39 ± 4 AF-HT vs 42 ± 6 AF-NT vs 27 ± 4 pg/mL healthy; p<0.05] in AF. In contrast, Ang-(1-7) was suppressed in AF patients [7 ± 1 AF-HT vs 4 ± 1 AF-NT vs 22 ± 6 pg/mL healthy; p<0.05]. Plasma aldosterone was preserved in AF and did not correlate with Ang II levels, suggesting Ang II-independent regulation. The Ang II AT
1
receptor antagonist losartan [50mg, PO] significantly reduced supine systolic blood pressure [25 ± 15 mmHg at 6 hrs after administration; p<0.05] in 9 AF-HT patients, indicating that elevated Ang II contributes to hypertension in AF. These findings suggest an imbalance in Ang II and Ang-(1-7) activity in AF independent of hypertensive status, which may reflect differences in ACE and ACE2 enzyme activity. The source of Ang II in these patients, in the absence of plasma renin activity, is still under investigation. The loss of renin activity is not due to reduced renin content, but may result from low substrate availability or defective enzyme activation. Regardless, Ang II appears to contribute to the supine hypertension of AF. Further, prorenin levels are elevated in hypertensive patients which could provide a stimulus for Ang II generation and actions. Collectively, these patients offer a unique model to study cardiovascular regulation and Ang II production in the absence of autonomic and traditional renin influences.
Abstract 236: Reduced Epigastric Artery Reactivity in a Non-Modulator Phenotype of Human Hypertension
Authors: Shafiq Qaiser , Reslan Ossama M , Orgill Dennis P , Williams Gordon H , Khalil Raouf A
Published: July 2021

In normal and modulator hypertensive individuals sodium intake modifies plasma levels and target tissue response to ANG II. This sodium-mediated modulation is defective in 25-30% of the hypertensive population, termed non-modulators. Non-modulators have insulin resistance (IR), abnormal renal function, polymorphisms in the renin-angiotensin-aldosterone system (RAAS) genes, increased tissue levels of ANG II particularly during liberal dietary sodium intake, and increased risk of cardiovascular (CV) damage. We hypothesized that the increased risk of CV damage in non-modulators reflects abnormalities in vascular function. Male hypertensive subjects were placed on restricted salt diet 10 mmol/day for 7 days and phenotyped as modulators (PRA 8.7 ng/ml/hr, HOMA-IR 1.0, ALDO 18.85 ng/dl, n=4, age ≈48) and non-modulators (PRA 8.8 ng/ml/hr, HOMA-IR 1.7, ALDO 8.52 ng/dl, n=3, age ≈60). The subjects were then placed on liberal salt diet (HS, 200 mmol/day for 7 days), BP was measured, then underwent subcutaneous surgery to isolate the superficial inferior epigastric artery for ex vivo vascular function studies. Systolic BP was 144.8 in modulators and 142.0 mmHg in non-modulators. Diastolic BP was 88.5 in modulators and 87.3 mmHg in non-modulators. In epigastric arteries, contraction to ANG II, phenylephrine (Phe), and KCl was less in non-modulators (0.24, 0.56, and 0.53) than in modulators (0.8, 1.43, and 1.1 g/mg tissue). Endothelium-dependent relaxation to acetylcholine (ACh) was not different between non-modulators (22.1) and modulators (22.6%). Bradykinin caused larger endothelium-dependent relaxation than ACh, but was still not different in non-modulators (57.8) vs. modulators (46.3%). In contrast, endothelium-independent relaxation to the nitric oxide (NO) donor sodium nitroprusside was reduced in non-modulators (64.2) vs. modulators (92.5%). The reduced vascular responsiveness to ANG II in non-modulators is consistent with increased vascular tissue RAAS activity, and desensitization to ANG II. The reduced vascular reactivity to the vasoconstrictors Phe and KCl and the vasodilator NO donors is consistent with vascular smooth muscle dysfunction and may explain the increased risk of CV damage in non-modulators during HS dietary intake.
Abstract 24: Autonomic Function and Obesity in the Coupling Between Interleukin-6 and C-Reactive Protein
Authors: Okamoto Luis E , Raj Satish R , Gamboa Alfredo , Shibao Cyndya , Arnold Amy C , Diedrich Andre , Farley Ginnie , Robertson David , Biaggioni Italo
Published: July 2021

C-reactive protein (CRP) is a marker of inflammation in obesity, induced in part by interleukin-6 (IL-6) derived from adipocytes. To test the hypothesis that sympathetic overactivity contributes to the increase in IL-6 and CRP, we measured these inflammatory markers in female subjects: 16 obese (42±2 yrs., BMI 37.5±1.3), 30 healthy controls (32±3 yrs., BMI 23.2±0.4), and 54 with postural tachycardia syndrome (POTS, 31±1 yrs., BMI 22.2±0.4), a condition characterized by increased sympathetic tone. We also included 3 patients with congenital absence of norepinephrine (dopamine ß-hydroxylase deficiency, DBH) as a comparison group for isolated sympathetic failure. Sympathetic activation, measured by low-frequency variability of blood pressure (LFSBP), was greater in obese and POTS compared to healthy controls (8.5±0.8 and 6.1±0.6 vs. 3.4±0.4 mmHg^2, P<0.01. Figure A). High-frequency heart rate variability (HFRRI), a marker of parasympathetic tone, was lower in POTS and in obese subjects compared to healthy controls (357±56, 402±146 and 1556±394 ms^2, respectively, P<0.01 for POTS vs. controls). IL-6 was higher in the obese and POTS groups compared to healthy controls (4.4±0.4 and 4.2±0.5 vs. 2.2±0.4 pg/mL, P<0.01. Figure B), but hsCRP was increased only in obese subjects (4.5±1.2 vs. 1.1±0.2 and 0.9±0.2 mg/L for POTS and healthy controls, P<0.01). We conclude that sympathetic activation and parasympathetic withdrawal are associated with increased serum IL-6 levels even in lean patients, but not with increased CRP. The coupling between IL-6 and CRP requires increased adiposity.
Abstract 244: Vascular Induction of Adam17 in vitro and in Vivo By Angiotensin Ii: Potential Involvement of a Hypoxia Responsible Element
Authors: Takayanagi Takehiko , Bourne Allison M , Kobayashi Tomonori , Yanagawa Nariaki , Takaguri Akira , Elliott Katherine J , Dubois Claire M , Eguchi Satoru
Published: July 2021

ADAM17 has been shown to play critical roles in angiotensin II (AngII)-dependent as well as independent types of pathophysiological vascular remodeling in vitro and in vivo. Enzymatic activation of ADAM17 by AngII has been described, however, little is known regarding regulation of ADAM17 protein expression in the cardiovascular system. Here we test our hypothesis that AngII induces ADAM17 protein expression to originate a feed forward loop of ADAM17 activation/induction in the vasculature. 8 week old control mice were infused with 1000 ng/kg/min AngII for 2 weeks via osmotic minipump. Serum starved rat VSMCs were stimulated with 100 nM AngII. ADAM17 expression was evaluated by immunohistochemistry and immunoblotting, respectively. In AngII-infused mice, marked ADAM17 induction was seen in vasculatures in heart and kidney, and carotid arteries and aortae. In VSMCs, AngII as well as PDGF-BB (50 ng/mL) time-dependently induced ADAM17 expression up to 24 hours (AngII 24h: 2.34±0.25 fold induction). Both AngII and PDGF-BB also stimulated ADAM17 promoter activity in VSMCs (AngII 24h: 2.90±0.17 fold induction). The ADAM17 promoter contains 6 typical hypoxia responsible elements (HREs). By using deletion and mutation constructs, the PDGF-BB response seems to require HRE4 located between -991 to -410 of the promoter. AngII-induced promoter activation was also lost in the HRE4 mutant. Moreover, both AngII and PDGF-BB stimulated HIF-1alpha protein expression in VSMCs at 4-8 hours. From these data, we conclude that AngII and PDGF induce ADAM17 expression in VSMCs via HIF1alpha/HRE-dependent transcriptional upregulation. The induction of ADAM17 via the HIF1/HRE-dependent mechanism likely promotes a feed-forward loop of ADAM17 activation/induction under a variety of pathophysiological conditions including hypoxia/ischemia leading to end organ damages in the cardiovascular system.
Abstract 250: Endothelial Cell Endothelin (ET-1) Production is Enhanced with Increasing NaCl Concentration.
Authors: Speed Joshua S , Pollock Jennifer S , Pollock David M
Published: July 2021

It has recently been demonstrated that increasing salt intake results in an accumulation of sodium within the interstitium of the skin of normal rats, which leads to an immune response that is necessary to maintain normal blood pressure. ET-1 mediates increased inflammation in several models of hypertension and is increased in response to high salt intake. However, it is unknown if ET-1 production is increased by endothelial cells in response to increasing NaCl concentration. Therefore, we hypothesized that increasing the media NaCl concentration will lead to an increase in ET-1 production by human umbilical venous endothelial cells (HUVECs). Exposure of HUVECs for 2 hours to a 40 mosm increase in NaCl results in a significant increase in ET-1 mRNA (1.65±0.14 fold increase vs. control; n=3, p<0.05). This increase in Na+ concentration is similar to that observed in the interstitium of the skin of rats placed on a high NaCl diet. Furthermore, exposure to +40 mosm of mannitol, an effective osmolyte, or urea, an ineffective osmolyte, had no effect on ET-1 mRNA (1.1 ± 0.04 fold change and 1.07 ± .08 fold change vs. control, respectively; n=3, p<0.05) suggesting that a direct effect of NaCl, not osmolality, is responsible for the increase in ET-1 mRNA. Moreover, +40 mosm of sodium acetate (NaAc) or choline chloride (ChCl) resulted in an increase in ET-1 mRNA very similar to that seen by increasing NaCl (1.74±0.14 (NaCl), 1.54±0.05 (NaAc), and 1.59±0.03 (ChCl) fold change vs. control, n=3, p<0.05), suggesting that either the Na or Cl ion increases ET-1 expression. These data demonstrate that vascular endothelial cells express ET-1 in response to increases in NaCl concentration, and may be important in mediating the extrarenal inflammatory response to a high salt diet.
Abstract 253: Sustained Activation of Toll-like Receptor 9 Increases Phenylephrine-Induced Contractions in Rat Mesenteric Resistance Arteries
Authors: Goulopoulou Styliani , Matsumoto Takayuki , Webb R. Clinton
Published: July 2021

Activation of Toll-like receptor 9 (TLR9) via bacterial or mitochondrial DNA induces systemic inflammation and is associated with heart failure and preeclampsia. TLR9 is expressed in the vasculature; however, whether activation of TLR9 affects vascular function is unknown. We hypothesized that sustained activation of TLR9 would increase rat mesenteric artery contractility. To test this hypothesis, female rats (16 weeks old) were injected intraperitoneally with a TLR9 agonist (ODN 2395, 0.1 μg/rat/day) or vehicle (saline) on 3 consecutive days and contractile responses to a thromboxane A
2
analog (U46619, 10
-9
-10
-5
M), potassium chloride (KCl, 10-80 mM), and phenylephrine (PE, 10
-9
-3x10
-5
M), in the presence and absence of a nitric oxide synthase inhibitor (LNNA, 10
-4
M) were measured in aortic and mesenteric rings from ODN- and vehicle-treated rats using a myograph. PE-induced contractions were increased in mesenteric but not in aortas from ODN-treated animals compared to vehicle group [E
max
(% max KCl), ODN-treated: 167±10 vs. Vehicle-treated: 113±13, (Fig. 1A)] and the magnitude of this difference remained unaltered following NOS inhibition (Fig. 1B). ODN 2395 treatment had no effect on vascular responses to U46619 or KCl in either mesenteric or aortic rings. In summary, in vivo TLR9 activation increases vascular contractility and this effect is vascular bed- and agonist-specific. We propose that chronic immune system activation due to multiple bacterial infections or accumulation of mitochondrial DNA increases vascular contractility via TLR9 signaling pathways leading to vascular dysfunction and contributing to the development of vascular disease.
Abstract 257: Autophagy in Endothelial Cell Has an Important Role for Hemostasis and Thrombosis
Authors: Torisu Takehiro , Torisu Kumiko , Toren Finkel
Published: July 2021

Autophagy has been reported to maintain intracellular homeostasis through lysosomal-mediated degradation of damaged organelles and proteins. Recent evidence suggests that autophagy regulates many physiological and pathological process including aging, reactive oxygen species levels, and inflammation. The role of autophagy in endothelial cell biology is poorly understood. Electron microscopic analysis of human umbilical vein endothelial cell (HUVEC) surprisingly demonstrated spontaneous fusion of autophagosomes with Weibel-Palade bodies, endothelial specific organelles containing abundant von Willebrand factor (VWF). Knockdown of the essential autophagy gene Atg7 resulted in a reduction in release of VWF from HUVECs after histamine (2.07±0.02 mU/mL vs. 1.30±0.02 mU/mL), or vascular endothelial growth factor (3.10±0.01 mU/mL vs. 1.22±0.03 mU/mL) stimulation. Pharmacological inhibition of autophagy showed similar results. We generated mice that have an endothelial specific deletion of Atg7. These mice have normal blood pressure (Control; 113±8/87±6 mmHg vs. Atg7 deficient; 119±7/88±4 mmHg) and normal vessel architecture. However, endothelial specific Atg7 deficient mice showed a reduction of plasma VWF and marked elevation of their bleeding times (The number of mice with bleeding time of more than 10min; Control=1/17, Atg7 deficient 6/9). Thus, an intact endothelial autophagy machinery is necessary for VWF secretion and hemostasis.
Abstract 260: Aging Decreases the Anticontractile Effect of Perivascular Adipose Tissue in the Mouse Aorta
Authors: Szasz Theodora , Carrillo-Sepulveda Maria Alicia , Webb R Clinton
Published: July 2021

The perivascular adipose tissue (PVAT) exerts an anticontractile effect via paracrine release of bioactive molecules. During vascular dysfunction associated with hypertension and obesity the anticontractile effect of PVAT is reduced or lost. Although vascular dysfunction associated with aging is well documented, there are no studies investigating whether PVAT plays a role in this context. We hypothesized that the PVAT anticontractile effect would be reduced with age. Mouse aorta from 3 and 9 month-old male C57bl6 mice was used in contractility experiments in the presence and absence of PVAT. Contractile responses to phenylephrine (PE) and serotonin (5-HT) were reduced in the presence of PVAT in both age groups (pD2 PE: young-PVAT=7.13±0.09, young+PVAT=6.24±0.09, old-PVAT=6.96±0.12, old+PVAT=6.49±0.18; pD2 5-HT: young-PVAT=6.74±0.08, young+PVAT=5.98±0.16, old-PVAT=6.58±0.08, old+PVAT=6.29±0.09). Relaxation responses to acetylcholine were not significantly changed by PVAT in either group. Despite an increased PVAT mass in the older mice, the magnitude of the anticontractile effect of PVAT was reduced in older compared to younger mice (% reduction PE contraction: young=66.6±7.8, old=49,1±15.4; % reduction 5-HT contraction: young=55.5±15.1, old=31.9±9.1). Inhibition of cystathionine gamma lyase (CSE), a hydrogen sulfide synthesizing enzyme, did not reverse the reduced 5-HT-induced contraction in PVAT intact aorta in either group. Our results show that the anticontractile effect of PVAT is reduced with age, potentially contributing to the vascular dysfunction observed in aging.
Abstract 267: Hemoglobin, Endothelial Cells, and TLRs. Common Connection?
Authors: Lisk Christina , Irwin David
Published: July 2021

Introduction:
Patients suffering from chronic hereditary hemolytic anemic syndromes, such as sickle cell disease (SCD) and thalassemia, are often at risk for systemic and pulmonary vascular disease. It has been suggested that chronic exposure to cell free hemoglobin (CFH) may contribute to some vascular diseases associated with these syndromes such as pulmonary arterial hypertension. To date, the vasculotoxic effects of CFH have mostly been attributed to its pro-oxidant and nitric oxide scavenging characteristics. However, emerging evidence suggests CFH may contribute to inflammation by directly activating a signaling cascade event by binding to a pattern recognition receptor (PRR) or a toll like receptor (TLR) on vascular endothelial cells. Hypothesis: We hypothesized that CFH would increase the activity of transcription factors, NF-κb and HIF-1α, via a MyD88-dependent pathway.

Methods:
Human microvascular endothelial cells (HMEC) were transfected with either an NF-κB or HIF-1α luciferase reporter gene and treated with CFH (ferrous, ferric, and ferryl forms) in the presence or absence of SOD, catalase, dexamethasome, MyD88 inhibitor, or, the PHD inhibitor, DMOG. Messenger RNA for HIF-1α and HIF-2 were also measured after treatments.

Results:
All three states of hemoglobin increased NF-κB and HIF-1α activity in a dose response fashion, with ferryl inducing the greatest activity of both NF-κB and HIF-1α. Time course studies showed that NF-κB and HIF-1α activity tracked together. A unique synergy was noted with co-treatment of ferryl and DMOG. Co-treatment with SOD or catalase did not inhibit the CFH-induced NF-κB or HIF-1α response. Dexamthasome and MyD88 inhibition reduced the CFH-induced NF-κB and HIF-1α activity.

Conclusion:
Our results support the hypothesis, that CFH may activate a TLR or PRR signaling cascade subsequently activating MyD88-NF-κB and HIF-1α. Our data, that showed SOD and/or catalase did not block CFH effects, suggests that this event is not mediated by CFH pro-oxidant characteristics. CFH-induced HIF-1α was blocked by NF-κB inhibition with either, Dexamethasome or MyD88 inhibition emphasizing the importance of NF-κB in the HIF-1α pathway.
Abstract 271: Evidence of Arterial Stiffness in Young Adult Women Born Extremely Preterm (<29 weeks).
Authors: Huyard Fanny , Vaujois Laurence , Bertagnolli Mariane , Cloutier Anik , Bigras Jean-Luc , Nuyt Anne Monique
Published: July 2021

Background:
Epidemiological studies reported that preterm infants have increased arterial systemic blood pressure in adulthood. We have recently shown in an animal model that premature vascular aging could be involved in this process.

Aim:
To assess biophysical properties (arterial stiffness) of the aorta as early signs of a vascular aging process in young adult women born extremely preterm.

Methods:
We studied 4 women (aged 24±1 years) born extremely preterm (26.1±0.5 weeks, 803±58 grams) in the absence of any significant medical or psychiatric co-morbidity. Subjects were compared to 6 control women born at term (40.6±0.8 weeks, 32518±139 grams) matched for age. The aortic diameters, the pulse wave transit time around the aortic arch and the ascending aortic peak flow were measured with echo-Doppler and the blood pressure recorded. Pulse wave velocity, aortic input impedance (Zi), characteristic impedance (Zc), arterial pressure-strain elastic modulus (Ep), and arterial wall stiffness index (βSI) were calculated.

Results:
Preterm women had slightly but not significantly increased arterial systolic blood pressure compared to young women born term (111±6 vs. 104±2 mmHg, p=0.23). Diastolic and mean arterial blood pressure were similar (62±4 vs. 61±3, p=0.84 and 77±4 vs. 75±3 mmHg, p=0.73 respectively). Pulse wave velocity did not differ between groups (3.6±0.6 vs. 3.2±0.2 m/sec, p=0.53). βSI and Ep, direct indices of central arterial rigidity, were not significantly different between preterm women compared to controls (4.9±2.1 vs. 3.7±0.4, p=0.46 and 58±24 vs. 42±4 kPa, p=0.38 respectively). Zc and Zi, indices of the resistance to ejection to blood flow, were increased compared to controls (134±21 vs. 105±9, p=0.18 and 185±8 vs. 152±10, p<0.05 dynes. sec. cm
-5
, respectively).

Conclusions:
This first series of results suggest that women who were born very preterm present indices of arterial rigidity compared to term controls. This alteration of the vascular tree could be a patho-physiological mechanism linking prematurity to adult cardiovascular diseases.
Abstract 277: Mutations in the KCNJ5 Gene Imply a Higher Lateralization Index at Adrenal Vein Sampling for Primary Aldosteronism
Authors: Seccia Teresa M , Mantero Franco , Letizia Claudio , Kuppusamy Maniselvan , Barisa Marlena , Miotto Diego , Rossi Gian Paolo
Published: July 2021

Background.
The mutations that affect the selectivity filter of the KCNJ5 K+ channel can play a role in triggering and/or maintaining aldosterone oversecretion in primary aldosteronism (PA). We therefore hypothesized that these somatic mutations can be associated with an increased aldosterone secretion from the APA, thus translating in raised plasma aldosterone concentrations (PAC) in the ipsilateral adrenal vein.

Aim.
To investigate if the lateralization index (LI) at adrenal vein sampling (AVS) is higher in the patients with an APA carrying the mutation (KCNJ5mut), as compared to those without the mutation (KCNJ5wt).

Methods.
Ninety-two consecutive PA patients who underwent AVS and received diagnosis of APA based on the four corners criteria were recruited. Unequivocal information on the presence or absence of the KCNJ5 mutations was available for each patient. The selectivity index (SI) was calculated as ratio between the right or left adrenal vein PCC (PCCside) and the infrarenal IVC PCC and a cutoff of 2.00 was used. The lateralization index (LI) was calculated in the bilaterally selective AVS as the ratio of PAC/PCC at the APA side to PAC/PCC at the contralateral side. We sequenced the KCNJ5 coding region spanning aminoacids 122 to 199, which include the selectivity filer.

Results.
The overall prevalence rate of KCNJ5 somatic mutations was 34%; G151R, L168R and T158A mutations were found in 19, 10 and 1 APA respectively. The G151E mutation was not found. The KCNJ5mut and KCNJ5wt groups were similar for gender, age, sK+ levels, while PAC and ARR were higher, and PRA lower (all p<0.05) in the KCNJ5 mut group. In the latter group the LI was higher than in the KCNJ5wt group (29.3± 6.7 vs 16.7±3.9, p< 0.02). This was due to a PAC/PCC ratio which was higher in the adrenal vein ipsilateral to the APA side and lower contralaterally in the KCNJ5mut group.

Conclusions.
These results provide direct in vivo evidence for a higher aldosterone secretion from APA carrying the KCNJ5 mutations, which translates into higher values of the LI, compared to the tumors without such mutations. Hence, the presence of these KCNJ5 mutations can affect the accuracy of the AVS-based diagnosis of the subtype of PA.
Abstract 296: The Effect of Migration on Cognitive Representations, Blood Pressure Level, and Dietary Habits in African Immigrant Women
Authors: Daramola Olubunmi , Scisney-Matlock Magaret
Published: July 2021

Migration has been associated with increased risk of hypertension(HTN) through stressors associated with cultural change and health behavior. Like other immigrants, women arriving in good health have experienced health declines with increased time in the U.S. The purpose of this study was to determine the effects of migration to, and residence in, the U.S. on the development and perceptions of HTN and dietary behavior (Dietary Approach to Stop Hypertension (DASH Diet)) using the Self-Regulation Model (SRM) of Leventhal et al. . This cross-sectional correlation research used two survey instruments (Women’s & Men’s hypertension Experiences & Emerging Lifestyle Survey (WHEELS) and Acculturative Stress Scale for International Students (ASSIS)) with a convenience sample of 91 Nigerian immigrant women (NIW) and a secondary data analysis of 38 African American women (AAW) from the WHEELS Study of 2008/2009 for comparison. Descriptive analysis was done on salient demographic variables for NIW and AAW. A t-test and ANOVA compared NIW and AAW and duration of residency in the U.S. with dependent variables (cognitive representations, blood pressure, and BMI). An important finding was that 63.7% (58 of 91) of NIW had BMI > 30 and 61.5% (56 of 91) had pre-HTN (SBP 120 to 139mmHg). Knowledge of HTN (HTNKNOW) and Cognitive Representation of Hypertension (CRHTN) were significantly increased in NIW by years of residency (p= .001 and .027 respectively). AAW had significantly higher HTNKNOW than NIW (p= .021). No significant differences were found for the CRHTN or Cognitive Representation of DASH Diet (CRDD) between AAW and NIW. However a significant difference was found in the CRDD dimension of perception representing knowledge ( p= .002). No differences were found in CRDD or its dimensions by years in the U.S. for NIW. An association exists between HTNKNOW and CRHTN and years of residence in the U.S., with none found with CRDD. Knowledge of the DASH diet was present in the NIW but there was no reflection of this in their BMI. There is a need to educate new immigrants of risk factors associated with HTN/CVD. A longitudinal study initiated on immigrants’ arrival in the U.S. is recommended to understand the trajectory of chronic illnesses such as hypertension.
Abstract 298: Cytochrome P4501A1 Contributes to Nitric Oxide-Dependent Vasodilation and Blood Pressure Lowering on an Omega-3 Polyunsaturated Fatty Acid-Enriched Diet
Authors: Agbor Larry N , Walsh Mary T , Walker Mary K
Published: July 2021

Cytochrome P4501A1 (CYP1A1) stereospecifically metabolizes omega-3 polyunsaturated fatty acids (n-3 PUFA) to potent vasodilators in vitro. We have previously reported that CYP1A1 knockout (KO) mice are hypertensive and exhibit significantly reduced vasodilatory responses to the n-3 PUFAs, eicosapentaenoic and docosahexaenoic acids. We next tested the hypothesis that CYP1A1 KO mice would exhibit significantly different vascular and blood pressure responses to diets enriched in n-3 versus n-6 PUFAs. CYP1A1 wildtype (WT) and KO mice were fed normal chow or diets enriched in either n-3 or n-6 PUFAs for 2 mo, and then blood pressure was assessed by radiotelemetry ± nitric oxide synthase (NOS) inhibitor (NG-nitro-L-Arginine). Acetylcholine (Ach)-mediated vasodilation was assessed in first order mesenteric arteries, and endothelial NOS and phospho-eNOS were measured in the aorta. We found that an n-3 enriched diet significantly reduced mean arterial pressure (MAP) in CYP1A1 KO mice (Chow: 116.0 ± 1.2; n-3 diet: 107.6 ± 1.5, p<0.05) with no effect in WT mice (Chow: 103.0 ± 0.9; n-3 diet: 105.0 ± 2.5). In contrast, an n-6 enriched diet significantly increased MAP in WT mice (Chow: 103.0 ± 0.9; n-6: 118.2 ± 4.1, p<0.05) with no effect in KO mice (Chow: 116.0 ± 1.2; n-6: 115.3 ± 1.5). Interestingly, NOS inhibition increased blood pressure significantly more in the CYP1A1 WT mice (+16 ± 0.5 mmHg) than KO mice (+11 ± 0.6, p<0.002) on an n-3 diet, but resulted in similar increases in blood pressure in both genotypes on an n-6 diet (WT: +11 ± 1.8; KO: +11 ± 0.8). In addition, CYP1A1 KO mice on an n-3 enriched diet exhibited significantly reduced Ach-dependent dilation in mesenteric arteries and reduced expression of aortic phospho-eNOS, compared to WT. However, neither of these endpoints were altered in KO mice on an n-6 diet, compared to WT. Taken together, these data suggest that CYP1A1 contributes to the NO-mediated vasodilation and blood pressure lowering benefits derived from dietary n-3 PUFAs.
Abstract 299: Low Calorie Cranberry Juice Lowers Blood Pressure in Healthy Adults
Authors: Novotny Janet A , Baer David J , Khoo Christina , Gebauer Sarah K
Published: July 2021

Dietary polyphenols have been shown to have a beneficial impact on blood pressure. To investigate the effect of daily consumption of a low calorie cranberry juice beverage (a rich source of polyphenols) on blood pressure of healthy adults (n=56), we conducted a parallel arm, double-blind, randomized, placebo-controlled trial. Volunteers were men (n=26) and women (n=30), aged 51+11 years, with a body weight of 79.3+8.8 kg and BMI of 28.4+4.3 (mean+SD). Treatments were a low calorie cranberry juice beverage or a color/flavor/calorie-matched placebo beverage, both of which were incorporated into a controlled diet for 8 weeks. During the controlled diet, volunteers consumed a base diet, consisting of typical American foods, scaled to meet their individual energy requirement such that body weight did not change during the study. Blood pressure was measured by a standardized protocol at the beginning of the intervention, after 4 weeks of treatment, and after 8 weeks of treatment. Systolic and diastolic blood pressure values for placebo and cranberry juice treatments at 4 weeks and 8 weeks were compared with a mixed model ANOVA. Blood pressure measures at 4 and 8 weeks of treatment for placebo and cranberry juice were also compared to baseline using a repeated measures ANOVA. After 8 weeks, diastolic blood pressure was significantly lower for the cranberry juice group compared to the placebo group (LSmeans + SEM of 72.2+1.1 mm Hg for placebo vs. 68.6+1.1 mm Hg for cranberry juice, respectively, p=0.029). When 8 week blood pressure values were compared to baseline, cranberry juice was associated with a significant decrease in diastolic BP (73.9+1.6 mm Hg at baseline vs. 70.9+1.6 mm Hg at 8 wk, p=0.049) and a trend toward decreased systolic BP (121.9+3.2 mm Hg at baseline vs. 118.6+3.1 mm Hg at 8 wk, p=0.12), while the placebo was associated with no change from baseline (systolic of 111.5+2.4 mm Hg at baseline vs. 112.3+2.2 mm Hg at 8 wk, p=0.89; diastolic of 68.1+1.5 mm Hg at baseline vs. 68.6+1.5 mm Hg at 8 wk, p=0.37). In conclusion, incorporation of a low calorie cranberry juice beverage into the diet of healthy adults appears to result in improvements in blood pressure.
Abstract 307: Endothelial mPGES-1 Mediates Thiazolidinedione-Induced Adipose-Specific Capillary Hyperpermeability and Fluid Retention
Authors: Yang Tianxin , Yang Guangrui , Aoyagi Toshinori , Sun Ying , Jia Zhanjun
Published: July 2021

Thiazolidinedione-induced fluid retention results from two prominent mechanisms: increased distal tubular fluid reabsorption and adipose-specific increases in capillary permeability; the later mechanism requires activation of endothelial but not smooth muscle PPARγ as demonstrated by using conditional knockout mice (Yang et al. 63rd High Blood Pressure Research Conference. #063, 2009). The present study examined the role of microsomal prostaglandin E synthase-1 (mPGES-1) in TZD-induced capillary hyperperbeability in the adipose tissues. Following rosiglitazone (RGZ) treatment, remarkable COX-2 and mPGES-1 inductions were detected at day 1 and peaked at day 2 (COX-2:104-fold for mRNA and 98-fold for protein; mPGES-1: 2.5-fold for mRNA and 30-fold for protein) in parallel with a 64-fold increase in PGE2 production in apidydimal fat depot (AFD) but not in other tissues tested, and declined at day 14. Body weight gain (BWG) in response to RGZ in WT mice were 1.62 g on day 14. In contrast, the BWG in mPGES-1 KO mice was completely blocked on day 7 and was reduced by 60% on day 14. RGZ-treated WT mice exhibited a 60% increase in water content in the AFD, which was significantly attenuated in the KO mice. In parallel, the capillary perbeability in the adipose tissue, as assessed by Evans blue leakage assay, exhibited a 60% increase in WT mice after RGZ treatment. As compared with WT controls, the adipose capillary permeability in the KO mice was 60% less at baseline and 100% less after RGZ treatment. RGZ-induced fluid retention was further tested in mice lacking mPGES-1 in endothelium or smooth muscle generated respectively by crossing mPGES-1 floxed mice with Tie-2-Cre or SM22-Cre mice (termed EC KO or SM KO). In EC KO mice, TZD-induced capillary hyperpermeability in adipose tissue was completely abolished, associated with a 50% reduction of the BWG and complete blockade of PGE2 stimulation in the ADF, a phenotype analogous to that of endothelial PPARγ KO mice. In contrast, neither water content nor capillary permeability in the skeletal muscle was affected by RGZ treatment. Taken together, this study has defined endothelial mPGES-1 as a key mediator of TZD-induced adipose-specific capillary hyperperbeability and fluid retention.
Abstract 31: Improvement of Salt-sensitive hypertension in SS-Mstnem1Mcwi Rats
Authors: Stepp David , Dunlap Robert H , Mintz James D
Published: July 2021

Hypertension afflicts nearly 1/3
rd
of American adults but exercise is known to help lower blood pressure by mechanisms which are not well-understood. Exercise increases muscle mass, which might in turn improve metabolism or lower peripheral resistance to improve blood pressure. To determine the effects of increased muscle mass on blood pressure regulation, pressure was monitored via telemetry in salt-sensitive rats in which myostatin (SS-Mstn) had been targeted for disruption by zinc finger nuclease technology through the PhysGen Knockouts program at the Medical College of Wisconsin. At 24-26 weeks of age, SS-Mstn were heavier (430+20 vs. 363+20,
p
<0.05) with larger muscles (gastrocnemius, 60%, gluteus maximus, 30%) compared to SS-controls. Body length was similar. At baseline on 0.4% salt diet, blood pressure was higher in SS-control (161+4 vs. 123+8 mm Hg,
p
<0.05) compared to SS-Mstn. When salt was elevated to 4%, the pressure increase was smaller in SS-Mstn (5+1 vs 14+3 mm Hg,
p
<0.05). Lowering dietary salt to 0.1% caused a larger drop in SS-control than SS-Mstn (19+6 vs. 3+2,
p
<0.05). Heart rate was similar on normal and low salt conditions but slightly higher in SS-control on high salt diet. In parallel, kidney mass was lower in SS-Mstn (1.4+0.1 vs 1.8+0.3,
p
<0.05) and peak responses to acetylcholine in aortic rings were larger in SS-Mstn (57+3 vs. 35+7 %,
p
<0.05). Vasoconstrictor responses to phenylephrine and serotonin were similar between groups as was vasodilation to nitroprusside. Taken together, these data suggest that an increase in muscle mass or a loss of myostatin signaling is of significant benefit in the regulation of arterial pressure. This may reflect improvements in vasodilator function but more extensive studies are needed to fully determine the mechanism of the blood pressure lowering effect.
Abstract 310: Aerobic Exercise Training Improves Blood Pressure Variability in Obese Female Mice.
Authors: Sartori Michelle , de Souza Leandro E , de Souza Pamella R , dos Santos Fernando , Malfitano Christiane , Malfitano Christiane , Ferreira Janaí B , Farah Vera , Krieger Eduardo M , Irigoyen Maria C , De Angelis Kátia
Published: July 2021

Background:
Clinical issues related with obesity and diabetes are focused not only on metabolic dysfunctons, but also on cardiovascular pathologies which are the likely cause of morbidity and mortality in these patients. In this sense, blood pressure variability (BPV) has been reported to be associated with an adverse cardiovascular prognosis. Ob/ob mice have been used as a model of type 2 diabetes and obesity. However, the effects of aerobic exercise training on cardiovascular parameters in this model are unknown.

Objective:
The aim of this study was to evaluate the blood pressure variability in trained youth obese mice.

METHODS:
Female ob/ob mice (4 weeks) were randomized into sedentary (OS, n=11) or trained (OT, n=8) (treadmill,5 days/w, 60 min/d, during 8 wks) groups. Blood glucose was measured by reagent strips. Arterial pressure signals were recorded using a data acquisition system.

Results:
The OT group had higher exercise capacity compared to the OS group. OT group had reduced body weight and blood glucose (45±2g, 133±3 mg/dL) compared to OS group (50±2g e 169±8 mg/dL). Mean arterial pressure and heart rate were similar between groups (OS: 106 ± 4mmHg and 513± 18bpm vs. OT: 104 ± 6 mmHg and 514±28bpm). The BPV and the low frequency band of BPV were higher in the OS (23 ± 3mmHg2 and 7 ± 1 mmHg2) compared to the OT group (15 ± 2 mmHg2 and 5 ± 1 mmHg2). Moreover, the spontaneous baroreflex sensitivity, represented by alpha index, was lower in the sedentary group (1.2 ± 0.3 ms/mmHg) compared to the trained group (1.9 ± 0.2 ms/mmHg).

Conclusion:
Our results suggest that early physical training in obese mice can be effective in attenuating the increase in weight and blood glucose in addition to improving blood pressure variability in these animals. Sources of funding: FAPESP,CNPq
Abstract 314: Elevation of (pro)renin and Its Receptor in Preeclampsia: A Rat Model and Human Patients
Authors: Uddin Mohammad N , Horvat Darijana , Fothergill Russell E , Kelso Kelsey R , Jones Richard O , Allen Steven R , Zawieja David C , Kuehl Thomas J
Published: July 2021

Preeclampsia (PreE), a syndrome manifesting with hypertension, proteinuria, and edema, is a leading cause of maternal and fetal morbidity and mortality. While preE triggers are likely many and elusive, the renin-angiotensin system (RAS) has been implicated in preE pathogenesis. However, there is no data showing involvement of (pro)renin and its receptor. We recruited 32 preE and 57 normal pregnant consenting patients. (Pro)renin levels were assayed in plasma samples using an ELISA kit. An established rat model of preE was used to evaluate the role of (pro)renin and its receptor in pathogenesis. We used normal pregnant rats (NP, n=10) and pregnant rats receiving weekly injections of desoxycorticosterone acetate and whose drinking water was replaced with 0.9% saline (PreE, n=10). The plasma and placental levels of (pro)renin were assayed by ELISA. The placental levels of (pro)renin receptor was measured by gel electrophoresis of the placental homogenate followed by detection with immunoblotting using anti-ATP6IP2 antibody. The ERK1/2 phosphorylation was analyzed by immunoblotting using antibodies to total and active ERK1/ERK2 in the placenta. The mean plasma (pro)renin of 0.27 ± 0.04 μg/mL in preE patients differ (p < 0.001 using Student’s
t
test) from 0.15 ± 0.05 μg/mL in those without preE. Both plasma and placental levels of (pro)renin were higher (p < 0.001 using Kolmogorov-Smirnov test) in PreE rats compared to NP (Plasma (pro)renin for NP:0.21 ± 0.04 and PreE:0.49 ± 0.09 pg/mL; placental (pro)renin for NP:152 ± 79 and PreE:302 ± 42 ng/g tissue). In addition to serving as a source of (pro)renin, the placenta is also a site for signaling as ERK1/2 phosphorylation is greater (p<0.05) in placental tissue of preE rats. These data show that circulatory and uteroplacental (pro)renin and its receptor are upregulated. Together with the upregulation of ERK1/2 phosphorylation in placenta of the rat model, there is now evidence of (pro)renin and its receptor associated novel RAS activation to play a role in preE pathogenesis through (pro)renin receptor-mediated detrimental cellular signaling at the placental boundary. This offers an opportunity for interventional treatments with signal inhibitors and interference with nonclassical (pro)renin activation of RAS.