bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 5129: Importance of Heart Rate for the Effects of Chronic Mental Stress on Endothelial Function and Ischemic Stroke
Authors: Custodis Florian , Gertz Karen , Prinz Vincent , Balkaya Mustafa , Böhm Michael , Endres Matthias , Laufs Ulrich
Published: April 2024

BACKGROUND:
The vascular effects of chronic mental stress are only partially understood. We therefore studied the effects of chronic mental stress on endothelial function and focal brain ischemia and characterized the role of heart rate and oxygen free radicals.

METHODS AND RESULTS:
Male C57/Bl6-mice were subjected to an established chronic stress protocol (restraint, exposure to rat, tail hanging) for 6 weeks. Mice were treated with the I(
f
)-channel-inhibitor ivabradine, 10 mg/kg/d, p.o. or vehicle. Chronic stress increased heart rate, which was reduced by ivabradine treatment (vehicle 514±10 bpm, vehicle/stress 570±14 bpm; iva/stress 485±7 bpm). Endothelium-independent vasorelaxation induced by glyceroltrinitrate and vasoconstriction induced by phenylephrine and KCl were similar in all groups, however, endothelium-dependent relaxation of aortic rings by carbachol was significantly impaired in mice exposed to stress. Heart rate reduction by ivabradine improved endothelial function in stressed animals in contrast to vehicle treatment. Vascular NADPH oxidase activity was increased to 223±38% and lipid hydroperoxides were increased to 314±26% in mice exposed to stress. Heart rate reduction with ivabradine significantly reduced NADPH oxidase activity (169±44%) and lipid peroxidation (187±58%). To test the relevance of these findings, mice were subjected to 30 min filamentous middle cerebral artery occlusion (MCAo), followed by 72 h reperfusion. Mice exposed to chronic stress before MCAo exhibited a markedly increased lesion size in comparison to unstressed controls (vehicle/naive: 23.92±2.41 mm
3
vs placebo/stress: 33.72±2.34 mm
3
). Heart reduction by ivabradine significantly reduced cerebral lesion size (iva/stress: 12.88±3.31 mm
3
). P<0.05 for all comparisons.

CONCLUSIONS:
Chronic exposure to mental stress impairs endothelial function and increases lesion area following ischemic stroke. Heart rate reduction by ivabradine diminishes the negative effects of chronic stress and protects from focal brain ischemia via reduction of vascular oxidative stress and amelioration of endothelial function. Those results identify the impact of heart rate as an important mediator of vascular effects induced by chronic mental stress.
Abstract 5133: Lifetime Risk of Stroke in Atomic-bomb Survivors-Adult Health Study in Hiroshima and Nagasaki, Japan
Authors: Takahashi Ikuno , Geyer Susan M , Fujiwara Saeko , Nishi Nobuo , Ohshita Tomohiko , Takahashi Tetsuya , Matsumoto Masayasu
Published: April 2024

Background
: It is suggested that Atomic-bomb radiation may cause increase in stroke mortality. The objective of this study was to estimate the radiation effect on lifetime risk (LTR) of stroke among Atomic-bomb survivors. Our hypothesis is that even low-dose radiation may cause stroke incidence in different mechanism of high-dose irradiation.

Methods
: We evaluated radiation effect on stroke incidence by dose and age at time of bombing (ATB) groups: < 0.005 Gy (n=2607), 0.005– 0.5 Gy (n=2051), 0.5–1.0 Gy (n=939), 1.0+Gy (n=824) and < 10 y.o. (younger) vs. ≥ 10 y.o. (older) ATB. Adult Health Study (AHS) subjects were Atomic-bomb survivors and unexposed controls. Participants have been followed biennially by RERF since 1958. Eligible subjects were alive and stroke-free at baseline age (55–56 y.o.) and had corresponding blood pressure data available. Stroke events were all reviewed by WHO MONICA methods using health exam and death certificate information. Cumulative incidence and LTR analyses accounted for the competing risk of non-stroke death with consideration of blood pressure levels.

Results
: Median follow-up for the 7487 subjects was 16.1 years (range: 1 day to 44.3 years), where 3788 subjects had died, 868 had a documented first-ever stroke event (356 male, 512 female). These stroke events were classified as hemorrhagic (n=231), thromboembolic (n=542), and unspecified (n=95). A minority of subjects (11%) was <10 y.o. ATB, and dose was unknown in 1066 subjects. There was no significant difference among 4 dose-groups in cumulative incidence rates of any stroke as well as hemorrhagic or thromboembolic stroke. However, there was a significant difference when we considered age ATB within dose groups (p=0.0003). Ten-years risk estimates for any stroke were 3.0% in 0 – 0.005 Gy, 2.0% in 0.005– 0.5 Gy, 5.0% in 0.5–1.0 Gy, 11.1% in 1.0+ Gy (p<0.0001), even within subtypes (hemorrhagic stroke; p=0.053, thromboembolic stroke; p=0.0034).

Conclusion
: Our results suggest that Atomic-bomb radiation in young subjects increases risk of stroke. Continued observation is needed due to the limited follow-up time in AHS subjects <10 y.o. ATB. This is the first report on the LTR of stroke incidence supporting the long-term radiation related increase in stroke mortality.
Abstract 5136: Reduction in Myocardial Ischemia-reperfusion Injury in Group IV Cytosolic Phospholipase A
2
-deficient Mice Partly Due to Inhibition of TNF
α
-mediated Pathway to Cell Injury
Authors: Saito Yukio , Watanabe Yousuke , Mishina Hideto , Watanabe Kazuhiro , Yano Toshiaki , Kobayashi Tsuyoshi , Obata Jun-ei , Kawabata Ken-ichi , Shimizu Takao , Kugiyama Kiyotaka
Published: April 2024

Type IV cytosolic phospholipase A
2
(cPLA
2
), which preferentially cleaves arachidonic acid from phospholipids, plays an important role in tissue injury. The downstream signal in response to TNF
α
, a key mediator of myocardial ischemia reperfusion (I/R) injury, involves cPLA
2
activation. This study examined a pathogenic role of cPLA
2
and its mechanistic link with TNF
α
in myocardial I/R injury using cPLA
2
α
knockout mice (cPLA
2
−/−
mice).

Methods and Results:
The cPLA
2
−/−
mice with C57BL/6 background used in this study had comparable heart size, heart rate and blood pressure with the littermate cPLA
2
+/+
(wild-type; WT) mice (male at 10 weeks).
In vivo
myocardial I/R was created in 10-week-old male mice by 1-hr ligation of the left anterior descending coronary artery, followed by 24 hrs of reperfusion. Expression levels of mRNA and protein of TNF
α
in the ischemic myocardium were increased from baseline by 5-fold similarly in both cPLA
2
−/−
and WT mice. Expression of TNF
α
receptors was unchanged after I/R in both genotypes. cPLA
2
−/−
mice had a 45% reduction in myocardial infarct size and a preservation of LV fractional shortening (25% vs. 15%, respectively) after I/R compared with WT mice. The contents of thromboxane B
2
and leukotriene B
4
, arachidonic acid-derived proinflammatory mediators, in injured myocardium were 40% ~ 50% lower in cPLA
2
−/−
mice than WT mice. cPLA
2
−/−
mice had a 30% decrease in caspase-3 activity and a 40% decrease in TUNEL-positive apoptotic cells in injured myocardium compared with WT mice. In cultured cardiomyocytes from WT mice, hypoxia-reoxygenation (H/R) induced cPLA
2
activation that was suppressed by preincubation with the TNF
α
-neutralizing antibody. Incubation of cardiomyocytes with TNF
α
induced apoptosis, cell damage (MTT assay) and production of thromboxane B
2
and leukotriene B
4
that were attenuated in cPLA
2
−/−
cardiomyocytes compared with WT cardiomyocytes. H/R exhibited similar results obtained from TNF
α
. Preincubation with the TNF
α
antibody significantly inhibited H/R-induced apoptosis and cell damage in WT cardiomyocytes, while it did not in cPLA
2
−/−
cardiomyocytes.

Conclusions:
Disruption of cPLA
2
attenuated myocardial I/R injury partly through inhibition of TNF
α
-mediated pathway to cell injury and apoptosis.
Abstract 5153: Platelet Activation and Inflammatory Response in Patients With Non-dipper Hypertension
Authors: Kaya Mehmet , Yarlioglues Mikail , Gunebakmaz Ozgur , Gunturk Ertugrul , Inanc Tugrul , Dogan Ali , Kalay Nihat , Topsakal Ramazan
Published: April 2024

Objective: We aimed to determine whether MPV and hs-CRP levels are elevated in non-dipper patients compared to dippers and healthy controls. In addition, we tried to find out if MPV and CRP are related to each other or not in non-dipper hypertensives.

Method: The total 126 patients study group included 86 patients with hypertension and 40 healthy subjects (16 male, mean age; 51±4) as control. Ambulatory blood pressure monitoring was performed for all patients. Hypertensive patients were divided into two groups; 46 dipper patients (18 male, mean age; 50±9) and 40 non-dipper patients (17 male, mean age; 53±11). Clinical baseline characteristics were similar between groups. We measured mean platelet volume in a blood sample collected in EDTA tubes and high-sensitive CRP was measured by using BN2 model nefelometer.

Results: Non-dipper patients demonstrated higher levels of MPV compared to dippers and normotensives (9.72±0.52 vs 9.38±0.33 and 8.92±0.42, p<0.05, respectively). High-sensitive CRP levels were also significantly higher in non-dippers compared to dippers and normotensives (4.9±1.7 vs 3.8±1.5 and 2.7±0.8, p<0.05, respectively). There was significant positive correlation between MPV and CRP levels (p=0.002, r=0.482) in non-dipper hypertensives.

Conclusion: Our results suggest that patients with non-dipping tend to have increased platelet activation and inflammatory response. Increased platelet activation and inflammatory response could contribute to increase the atherosclerotic risk in non-dipper patients compared to dippers.
Abstract 5155: Superoxide-Dependent Cathepsin Activation System is Associated with Hypertensive Renal Remodeling and Represents a Target for Statin
Authors: Cheng Xian Wu , Okumura Kenji , Sasaki Takeshi , Unno Kazumasa , Izawa Hideo , Hirashiki Akihiro , Nagata Kohzo , Kuzuya Masafumi , Yokota Mitsuhiro , Murohara Toyoaki
Published: April 2024

Objective:
Cathepsins are members of the cysteine protease family that participate in various types of tissue remodeling. Given that NADPH oxidase is implicated in protease activation, we examined the possible role of NADPH oxidase-dependent cathepsin activation in hypertensive renal remodeling with heart failure (HF) in Dahl salt-sensitive (DS) rats.

Methods and Results:
DS rats maintained on a high-salt diet were randomly assigned to four groups ((
n
= 10 for each group) that were treated with either vehicle (0.5% carboxymethyl cellulose; CMC), low-dose pitavastatin (1 mg/kg/d; Pitava-L), high-dose pitavastatin (3 mg/kg/d; Pitava-H), E64d (a cysteine protease inhibitor), or pitavastatin from 12 to 19 weeks of age. Rats fed a low-salt diet served as controls. Marked cortical mesangial matrix expansion and the levels of collagen type I and III, angiotensin II type receptor 1 (AT
1
R), and mineralocorticoid receptor (MR) mRNAs and the activity of cathepsin S and its protein in the kidney were increased in the CMC group with HF at 19 weeks compared with control rats. Immunostaining showed strong signaling for cathepsin S in the glomerular cells in the kidney of HF rats. Treatment with either dose of pitavastatin reduced the extent of fibrosis, the collagen type I and III mRNAs, and cathepsin S activity and its protein expression compared with those in CMC rats. The decrease in the ratio of reduced to oxidized glutathione and the increase in macrophage infiltration and NADPH oxidase activity as well as its subunits (including p22phox and gp91phox) and superoxide production apparent in the kidney of CMC rats were also inhibited by pitavastatin in a dose-dependent manner. These benefic effects of pitavastatin were partially mimicked by E64d and accompanied by amelioration of kidney fibrosis. Furthermore, both doses of pitavastatin reduced the levels of AT1R and MR mRNAs but not plasma angiotensin II levels.

Conclusions:
This is the first report showing that cathepsins are likely to trigger and promote kidney remodeling, and that pitavastatin suppresses the cathepsin activation system by the inhibiting NADPH oxidase-dependent superoxide anion production, leading to the prevention of kidney remodeling in hypertensive HF rats.
Abstract 5158: Opposite Effects of Salusins on the Development of Atherosclerotic Plaques
Authors: Watanabe Takuya , Nagashima Masaharu , Arita Shigeko , Hongo Shigeki , Shichiri Masayoshi , Hirano Tsutomu , Miyazaki Akira
Published: April 2024

Background:

Human salusin-
α
and -
β
are 2-related peptides processed from the same precursor, preprosalusin. Our previous studies
in vitro
showed that human macrophage foam cell formation is stimulated by salusin-
β
but suppressed by salusin-
α
(

Circulation

2008
;
117
;
638
– 48

). Thus we assessed the effects of salusin-
α
and -
β
on atherosclerotic plaque formation
in vivo
in apoE-KO mice. Further, we investigated the relationship between serum salusin-
α
levels and carotid atherosclerosis in patients with essential hypertension.

Methods and Results:

Saline, salusin-
α
or -
β
(600 pmol/kg/h) was continously infused through osmotic minipumps into 13-week-old apoE-KO mice. Aortic atherosclerosis, oxidized LDL-induced cholesterol ester accumulation (foam cell formation), and its related gene expression in exudate peritoneal macrophages were determined. After 4-week infusion of salusin-
β
, atherosclerotic lesions were 2.6-times greater than vehicle controls, which paralleled 1.9-fold increase in foam cell formation and upregulation of scavenger receptors (CD36, scavenger receptor class A) and acyl-CoA:cholesterol acyltransferase-1 (ACAT1). In contrast, salusin-
α
decreased serum total cholesterol levels by 15% and foam cell formation by 68% partly due to ACAT1 downregulation. After 8-week infusion of salusin-
α
, atherosclerotic lesions were significantly suppressed by 54% compared with vehicle controls. Clinically, serum salusin-
α
levels were significantly lower in patients with essential hypertension than healthy volunteers (9.4±0.9 pM [n=70] vs 17.0±3.5 pM [n=20],
P
<0.005). In all subjects, serum salusin-
α
levels became significantly lower in accordance with the severity of carotid plaque score and intima-media thickness (
P
<0.05). Immunoreactive salusin-
α
expression was at trace levels in human carotid plaques.

Conclusins:

We provided the first evidence that salusin-
β
accelerates atherosclerotic lesion development by upregulation of scavenger receptors and ACAT1 in apoE-KO mice. In contrast, salusin-
α
exerts anti-atherosclerotic effects by suppressing serum total cholesterol levels and ACAT1 expression. Decreased levels of salusin-
α
in circulating blood and vascular tissue have a close linkage with human atherosclerosis.
Abstract 5159: Arterial Wall Expression of Tumor Necrosis Factor Receptor-2 Attenuates Atherosclerosis by Reducing Recruitment of Monocyte/Macrophages
Authors: Zhang Lisheng , Brian Leigh , Freedman Neil J
Published: April 2024

Deficiency of tumor necrosis factor receptor-2 (TNFR2) increases TNF-induced endothelial cell apoptosis, decreases the rate of vein graft re-endothelialization, and consequently increases vein graft neointimal hyperplasia. We therefore tested the hypothesis that TNFR2 expression in the arterial wall protects against atherogenesis, by placing common carotid arterial interposition isografts from
tnfr2
−/−
or congenic wild type (WT) mice into the common carotid arteries of congenic apolipoprotein E
−/−
mice fed normal chow. We used a procedure we previously demonstrated engenders typical atherosclerosis, but in an accelerated time frame. Grafts were harvested 7 weeks post-op, perfusion-fixed, paraffin-embedded, sectioned at 4
μ
m, and stained for collagen and elastin. Computerized morphometry was performed by observers blinded to specimen identity. Eccentric lesions with fibrous caps and necrotic cores developed, and demonstrated up to 85% luminal stenosis. Compared with WT carotid grafts (n=6),
tnfr2
KO carotid grafts (n=5) demonstrated significantly more atherosclerosis, with 33% greater neointimal area (0.16±0.03 vs. 0.12±0.01 mm
2
, p<0.01). However, medial area was equivalent in WT and
tnfr2
KO arteries (0.12±0.02 vs. 0.10±0.04 mm
2
). Outward remodeling tended to be greater in
tnfr2
KO arteries (external diameter was 14±1% greater); consequently, luminal stenosis was comparable between
tnfr2
KO and WT arteries (89±8% vs. 86±14%).
Tnfr2
KO arteries not only developed larger neointimal lesions but also showed evidence for more unstable plaque composition: macrophage prevalence was 80±10% higher (p<0.05), and SMC prevalence was 43±5% lower in
tnfr2
KO than in WT arteries (p<0.05), as assessed by quantitative immunofluorescence microscopy for F4/80 (macrophages) and SMC
α
-actin (normalized to Hoechst 33342-stained nuclear fluorescence). Concordantly, immunofluorescence of vascular cell adhesion molecule-1 per cell was 70±20% greater in
tnfr2
KO carotid grafts (p<0.05). We conclude that TNFR2 expression in arterial wall cells protects against atherogenesis, by mechanisms that reduce monocyte/macrophage recruitment to the atheroma.
Abstract 5160: Apelin Modulates Adipocyte and Inflammatory Cell Processes to Inhibit Atherosclerosis
Authors: Kojima Yoko , Kundu Ramendra , Leeper Nicholas J , Chun Hyung J , Quertermous Thomas
Published: April 2024

Background: The G-protein coupled receptor APJ and its ligand apelin have many physiological roles in the cardiovascular system, although its overall impact and mechanism of effect on atherosclerosis remain controversial.

Methods and Results: Apelin knockout male mice were bred with ApoE knockout (ApoE KO) mice to generate double knockout (DKO) mice. DKO and ApoE KO mice were fed a normal diet for 20 weeks, and atherosclerotic lesions were analyzed histologically in the aortic sinus and by en face analysis. DKO mice developed more atherosclerosis in the thoracoabdominal aorta than ApoE-KO mice (percent plaque area; 5.36±0.55 vs. 2.53±0.54, p<0.05). Lesion area in the aortic sinus was also increased in DKO compared to ApoE-KO (0.30±0.14 vs. 0.15±0.04 mm2, p<0.05). Histological analysis showed that there was no difference in macrophage or smooth muscle content between genotypes, and studies of reactive oxygen species also did not show a significant difference. Because of recent evidence that the apelin-APJ pathway modulates insulin action, we investigated metabolic parameters and those associated with insulin resistance in the mouse models. DKO mice had significantly greater body weight and fat weight, and glucose tolerance testing showed the DKO mice to be insulin resistant. Also, the mRNA expression of TNF-a, IL-6, and MCP-1 in visceral fat tissue was increased in DKO compared with ApoE KO mice. Similarly, in cultured NIH 3T3 cells, apelin treatment decreased LPS-induced MCP-1 mRNA expression. In related studies, we investigated macrophage function in a foam cell assay, and found there was increased CD36 mRNA in aorta, and increased oil red O positive staining cells in peritoneal macrophage preparations from DKO mice compared with those from ApoE-KO mice.

Conclusion: Apelin-APJ signaling inhibits atherosclerosis through multiple mechanisms, including modulation of inflammation and metabolic effects in macrophages and adipose tissues.
Abstract 5193: Syndecan-1 is Protective in Atherosclerosis
Authors: Haller Carolyn A , Smith Sumona , Wen Jing , Xiao Jiantao , Chaikof Elliot L
Published: April 2024

Background
: Syndecan-1 is a cell surface heparan sulfate proteoglycan characterized by highly regulated expression during development, neoplasia, and wound repair. The biological function of syndecan-1 is primarily exerted via pendant glycosaminoglycans that sequester and regulate the activity of heparin-binding growth factors and chemokines. Several studies have documented a protective role for syndecan-1 in inflammatory disease; however, the functional role syndecan-1 in atherosclerotic lesion formation has not been previously investigated.

Methods:
Standard cross-breeding was used to generate ApoE
−/−
Sdc-1
−/−
double knockout mice which were maintained on a Western diet for 8 weeks to induce atherosclerotic lesion formation, results were compared to ApoE
−/−
Sdc-1
+/+
mice (n=19 each group). Brachiocephalic lesion area was quantified in 3 consecutive (hematoxylin and eosin stained) tissue sections with a 50
μ
m interval distance. Standard immunohistochemistry was used to characterize both murine and human atherosclerotic tissue samples. Serum was collected at 8 weeks via cardiac puncture, circulating levels of syndecan-1 were analyzed using slot blot analysis with mAb against mouse syndecan-1 (281–1).

Results:
A significant increase in atherosclerotic lesion area was measured in ApoE
−/−
Sdc-1
−/−
mice verses ApoE
−/−
Sdc-1
+/+
(88.03±8.66 vs. 57.40±8.08,
P
< 0.05). Atherogenic animals expressed syndecan-1 positive macrophages in early lesions and advanced lipid cores, correlative staining with human carotid plaques revealed infiltration of syndecan-1 positive macrophages in all specimens. Serum syndecan-1 was undetectable in native mouse serum, soluble syndecan-1 was observed in all mice after 8 week enrollment on the Western diet.

Conclusions:
The expression of syndecan-1 is significantly increased in the vascular wall of atherogenic mice and is present in human carotid plaque specimens. ApoE
−/−
Sdc-1
+/+
displayed a significant decrease in lesion area verses ApoE
−/−
Sdc-1
−/−
mice, syndecan-1 may be an important endogenous modulator of vascular inflammation.
Abstract 5196: LAR Deficiency Impairs Endothelial Barrier Function and Enhances Susceptibility to Atherosclerosis
Authors: Li Juxiang , Niu Xi-Lin , Runge Marschall S , Madamanchi Nageswara
Published: April 2024

Vascular endothelium forms a selective semipermeable barrier that regulates vital physiological functions such as tissue-fluid hemostasis and host defense. Impairment of endothelial barrier function is an early step in vascular dysfunction, which ultimately leads to atherosclerosis. The endothelial adherens junction (AJ), a multi-protein complex consisting of VE-cadherin and its associated catenins:
β
-catenin,
γ
-catenin and p120-catenin, regulates endothelial barrier function. Protein tyrosine kinases and phosphatases (PTPs) regulate AJ integrity and vascular permeability by modulating protein tyrosine phosphorylation. To determine the role of leukocyte antigen-related (LAR) PTP in endothelial barrier function, we investigated whether LAR associates with and/or regulates tyrosine phosphorylation of AJ proteins and the paracellular pathway. LAR expression in human umbilical vein endothelial cells (HUVEC) and brain microvascular endothelial cells was localized to EC-EC boundaries. Knockdown of LAR impaired (by 129.8%), whereas overexpression enhanced (by 48%) barrier function in HUVEC, as measured by flux of 40 KDa FITC-Dextran through cell monolayers. Reciprocal co-immunoprecipitation and co-localization with double-label fluorescence microscopy demonstrated the interaction of LAR with VE-cadherin and
β
-catenin. When glutathione S-transferase-cLAR (cytosolic LAR) was incubated with HUVEC lysate or with purified recombinant cytosolic VE-cadherin, LAR directly bound to VE-cadherin. Glutathione S-transferase-cLAR also directly bound to
β
-catenin in HUVEC lysate. Overexpression of LAR decreased tyrosine phosphorylation of VE-cadherin and
β
-catenin in postconfluent HUVEC. Consistent with these findings, aortic endothelial permeability and bradykinin induced microvascular leakage in pial venules were increased in apoE−/−/LAR−/− mice compared with apoE−/− mice. Furthermore, apoE−/−/LAR−/− mice fed Western diet for 3 month had a significant increase in aortic atherosclerotic lesion formation compared with apoE−/− mice (p = 0.0198). Together these data indicate that LAR regulates endothelial barrier function and dysregulation of this phosphatase may result in vascular pathophysiology.
Abstract 5198: Histamine H1 Receptor Promotes Atherosclerotic Lesion Formation by Increasing Vascular Permeability for Low Density Lipoproteins
Authors: Rozenberg Izabela , Rohrer Lucia , Sluka Susanna H , Hofmann Janin , Becher Burkhard , Soliz Jorge , Mocharla Pavani , Akhmedov Alexander , Borén Jan , Steffel Jan , Watanabe Takeshi , Luscher Thomas F , Tanner Felix C
Published: April 2024

Enhanced endothelial permeability with intimal accumulation of low density lipoproteins (LDL) stimulates the formation of atherosclerotic lesions. Histamine is known to increase vascular permeability. Here we demonstrate that
ApoE
−/−
mice treated with a histamine H1, but not H2 receptor antagonist developed 40% less atherosclerotic lesions in the aorta than placebo treated controls. Similarly, genetic deletion of the H1, but not H2 receptor resulted in 60% reduction of lesions compared to
ApoE
−/−
controls. The H1 receptor enhanced permeability for LDL and lipid accumulation in aorta, whereas plasma lipoprotein levels remained unaffected. In contrast, the H1 receptor did not affect proliferation and migration of vascular smooth muscle cells. Bone marrow transplantation confirmed that the formation of atherosclerotic lesions depended on the H1 receptor on vascular cells, while its presence on bone marrow-derived cells was irrelevant for plaque development. Mice expressing the H1 receptor exhibited higher levels of the chemokine CCL5 and higher numbers of macrophages and lymphocytes in plaques, higher numbers of circulating lymphocytes, and larger spleens. These observations indicate that H1, but not H2 receptor activation drives the formation of atherosclerotic lesions through an increased vascular permeability for LDL, which is associated with an enhanced secondary aortic and systemic inflammation.
Abstract 5202: Increased Aortic Stiffness in Young Subjects With Migraine
Authors: Schillaci Giuseppe , Pucci Giacomo , Corbelli Ilaria , Sarchielli Paola , Mannarino Massimo R , Pirro Matteo , Calabresi Paolo , Mannarino Elmo
Published: April 2024

Background: Migraine is associated with an increased risk for ischemic stroke and other cardiovascular (CV) events, including angina, myocardial infarction, and CV death. However, the mechanisms which link migraine to CV disease remain uncertain. In the present case-control study, we hypothesized that aortic stiffness, a direct measure of aortic stiffness and an independent predictor of stroke and cardiovascular disease, may be increased in young migraineurs with no overt CV disease or major CV risk factors.

Methods and Results: We studied 41 individuals with migraine (age 31±8 years, 82% females, blood pressure 118/73±12/9 mmHg) and 41 age- and sex-matched healthy control subjects. In all participants, carotid-to-femoral pulse wave velocity was determined by applanation tonometry (SphygmoCor). Cases and controls were free from overt CV disease, diabetes, and major CV risk factors. Subjects with migraine had a higher aortic pulse wave velocity than matched control subjects (7.4±1.2
vs
6.5±1.1 m×s
−1
, p=0.001). Age, mean arterial pressure as a measure of distending pressure and the presence of migraine (all p<0.05) independently predicted aortic pulse wave velocity when a consistent number of cardiovascular risk factors was simultaneously controlled for.

Conclusions: Migraine is independently associated with an increased aortic stiffness. This finding, obtained in young subjects without major cardiovascular risk factors, may represent one possible mechanism underlying the increased cardiovascular risk in patients with migraine.
Abstract 5205: Aortic Arch Calcification Detectable on Chest X-ray is a Strong Independent Predictor of Cardiovascular Events Beyond Traditional Risk Factors
Authors: Iijima Katsuya , Son Bo-Kyung , Ota Hidetaka , Ogawa Sumito , Eto Masato , Hashimoto Masayoshi , Akishita Masahiro , Ouchi Yasuyoshi
Published: April 2024

Background:
Aortic stiffness resulting from calcification makes management of hemodynamic status more difficult. Some reports have previously shown that simple assessment of aortic calcification in aortic arch and abdominal aorta using plain radiography can predict cardiovascular (CV) events. However, these studies simply assessed whether aortic calcification detectable on X-ray was present or absent, without considering the grade of calcification. In this study, we evaluated the validity and usefulness of grading aortic arch calcification (AAC) to predict new CV events, and compared it to traditional atherosclerotic risk factors.

Methods and Results:
This study enrolled 239 asymptomatic outpatients (mean age 61±14 years) without previous CV events. We divided the extent of AAC into four grades (from 0 to 3) by reviewing a postero-anterior plain chest X-ray. AAC grade was 0, 1, 2, and 3 in 46%, 22%, 29%, and 4% of the subjects, respectively. AAC grade was positively related to age, prevalence of diabetes and chronic kidney disease (CKD), and showed a significant association with clustering of traditional risk factors. In addition, impairment of endothelial function, as determined by flow-mediated dilation (FMD), was also associated with increasing AAC grade. Thirty two new CV events in total occurred during a mean follow-up period of 40±19 months. With multivariate adjustment, Kaplan-Meier analysis showed that the new incidence of CV events was significantly higher in patients with high AAC grade (grades 2 and 3) than in those with grade 0 or 1 (p<0.01, log-rank test). Multivariate Cox-proportional hazards analysis showed that the predictive value of AAC grade for CV events was significantly stronger (hazard ratio, 1.8; 95% confidence interval, 1.2–2.8;
p
<0.01) than that of FMD, HbA1c, and estimated GFR. In addition, predictive usefulness was found even in patients without CKD.

Conclusion:
AAC detectable on chest X-ray is a strong independent predictor of CV events. Beyond traditional risk factors including endothelial dysfunction, risk stratification by assessment of AAC may provide important information for primary preventive management of atherosclerotic disease.
Abstract 5210: Redox Regulation of ATP-sensitive Potassium Channels: A Possible Role for Thioredoxins
Authors: Bao Li , Delaroche Diane , Malester Brian , Coetzee William
Published: April 2024

Cardiac ATP-sensitive potassium (K
ATP
) channels are gated by intracellular nucleotides, which link energy metabolism to membrane excitability and consequent contractility. However, there is an increasing realization that the K
ATP
channel is also under the control of other associated proteins belonging to channel megadalton complex. Using bioinformatic approaches we identified a possible coiled-coil (CC) domain in SUR subunits. To identify proteins that associate with SUR subunits, we used this CC-domain as the bait in a two-hybrid screen against a rat cardiac cDNA library and identified thioredoxin 2 (Trx2) as a putative candidate. We confirmed interaction between Trx2 and the SUR CC-domain using GST pull-down assays. In a heterologous expression system we further demonstrated using co-immunoprecipitation assays that both forms of thioredoxin (Trx1 and Trx2) interact with full-length SUR1 or SUR2. Immunoprecipitation of SUR1 from MIN6 cells was followed by mass spectrometry, which confirmed that Trx1 natively associates with SUR1 subunits. Given that thioredoxins act as antioxidants to reduce proteins by cysteine thiol-disulfide exchange, our data suggest that K
ATP
channel activity is likely regulated by redox state. To examine this hypothesis, we assessed the effects of oxidation with hydrogen peroxide (H
2
O
2
; 10
μ
M to 1.5 mM) on the activity of K
ATP
channels (Kir6.2/SUR1) expressed in CHO cells using patch clamp techniques. H
2
O
2
had no effect on K
ATP
channels in the absence of ATP. When channels were partially blocked by sub-maximal levels of ATP (10
μ
M to 1 mM), H
2
O
2
dose-dependently increased channel activity. Interestingly, low H
2
O
2
concentrations (10 to 30
μ
M) transiently activated K
ATP
channels, whereas higher concentrations (>300
μ
M) caused a sustained activation. H
2
O
2
decreased the channel sensitivity to ATP (IC
50
8.9±0.26 vs. 21.7±0.15 uM; n = 9 –10) and had no effect on MgADP sensitivity. Our data demonstrate that oxidation (which occurs with ischemia/reperfusion) activates K
ATP
channels and suggest that thioredoxins, as components of the K
ATP
channel macromolecular complex, may regulate its response to cellular redox state.
Abstract 5213: Correlations Between Reciprocal ST-segment Depression on the Baseline Electrocardiogram, Angiographic Findings and Clinical Outcomes in Patients With STEMI Treated With Primary PCI
Authors: Farkouh Michael E , Nikolsky Eugenia , Reiffel James , Dressler Ovidiu , Baran David A , Mehran Roxana , Lansky Alexandra J , Stone Gregg W
Published: April 2024

Objective
- To investigate correlations between reciprocal ST-segment depression on the baseline ECG, angiographic findings and clinical outcomes in patients with acute ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI).

Methods
- Among 3602 pts enrolled in the prospective, randomized Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial, 2401 pts had the baseline ECG analyzed by an independent ECG core lab as part of a formal substudy. Reciprocal ST-segment depression defined as >0.1 mV depression in ≥1 adjacent leads in a territory remote from the site of ST-segment elevation was present in 1559 (64.9%) pts. Patients with posterior infarction were excluded. Angiographic analysis was performed by independent angiographic core lab.

Results
- Reciprocal ST-segment depression on baseline ECG correlated with higher incidence of non-LAD infarct vessel (72.2% vs. 37.9%), baseline TIMI flow grade 0/1 (67.6% vs. 57.3%), higher incidence of thrombus on baseline angiogram (84.3% vs. 75.2%), larger reference vessel diameter (median: 2.9 vs. 2.8 mm) and shorter time from symptoms onset to 1
st
balloon inflation (median: 215.0 vs. 234.0 min) [all p<0.0001] but not with incidence of multivessel disease (58.4% vs. 54.7%, p=0.08) or lower baseline LVEF (median: 60.2% vs. 59.6%, p=0.55). Clinical outcomes are presented in the Table

. By multivariable analysis, baseline reciprocal ST-segment depression was not predictive of mortality at 30 days (hazard ratio [95%CI] = 1.00 [0.38, 2.66], p=0.99) or at 1 year (hazard ratio [95%CI] = 1.00 [0.47, 2.16], p=0.99).

Conclusion
- Reciprocal ST-segment depression on the presenting ECG does not predict an adverse prognosis in patients with STEMI treated by primary PCI and is not correlated with multivessel disease or more extensive myocardial damage as assessed by LVEF.
Abstract 5215: Plaque Color in the Culprit Lesion is Associated With Incidence of Revascularization After Percutaneous Coronary Intervention for Acute Myocardial Infarction
Authors: Saratani Kazushi , Iwanaga Yoshitaka , Hayashi Takahiro , Miyazaki Shunichi
Published: April 2024

Purpose
: Plaque color is reported to have close relationship with the plaque vulnerability and the onset of acute coronary syndrome (ACS). However, few data are available on the relationship between plaque color and clinical outcome after the onset of acute myocardial infarction (AMI). Therefore, we evaluated the relationship of in vivo plaque color by coronary angioscopy (CAS) with the long-term clinical outcome including revascularization in patients after percutaneous coronary intervention (PCI) for AMI.

Methods:
Consecutive 230 patients with AMI were enrolled in the present study. The culprit lesions immediately before PCI were examined by CAS and were classified into three groups according to the color grade of the plaques: thick yellow plaque (TYP), yellow plaque (YP), or light yellow plaque (LYP).

Results:
There were no differences in lipid profile and other coronary risk factors among the three groups. However, during the follow-up of 2 years, the incidence of major adverse cardiac event (MACE) was significantly less in patients with TYP than those with YP or LYP by Kaplan-Meier analysis (P=0.006), which was driven primarily by a decreased incidence of revacularization (P=0.018). Furthermore, TYP was an independent predictor for long-term MACE after adjustment of predictive factors (age, Killip class, multivessel coronary artery disease, ejection fraction and body mass index).

Conclusions:
In AMI patients treated with PCI, the TYP in the culprit lesion independently predicted the long-term favorable prognosis, mainly due to less revascularization. This relationship might provide new insights for prevention of the secondary cardiac events after AMI.
Abstract 5270: Vascular Function and Vascular Inflammation in Polycystic Kidney Disease
Authors: Heffernan Kevin S , Rudym D , Kuvin Jeffrey T , Karas Richard H , Miskulin D , Perrone R , Sarnak M , Menon V
Published: April 2024

Background:
Polycystins, which have been localized to vascular smooth muscle cells, may lead to vascular dysfunction and contribute to cardiovascular disease in autosomal dominant polycystic kidney disease (ADPKD). We examined vascular function and vascular inflammation in ADPKD.

Methods:
This is an ancillary study to the Halt Progression in PKD Study, which is examining the effect of renin-angiotensin-aldosterone blockade on progression of ADPKD. We used peripheral arterial tonometry to assess augmentation index (AIx), a measure of arterial stiffness and wave reflection, in 52 ADPKD patients with hypertension and glomerular filtration rate (GFR) 25– 60 ml/min/1.73 m
2
, 50 ADPKD patients with hypertension and GFR >60 ml/min/1.73 m
2
, and 51 healthy controls. We measured serum levels of soluble intercellular adhesion molecule-1 (sICAM-1), vascular cell adhesion molecule-1 (VCAM-1), p-selectin, e-selectin, soluble Fas, and Fas ligand (FasL) as markers of vascular inflammation.

Results:
AIx, sICAM, p-selectin, and Fas were higher, and FasL was lower in subjects with ADPKD (p<0.05, Table

). Adjusting for age, race, height, heart rate, and mean arterial pressure had no effect on group differences in AIx (healthy control = 8%, ADPKD GFR >60 = 21%, ADPKD GFR 25– 60 = 20%). Group means were significantly different even after adjustment for vascular inflammatory markers (healthy control = 3%, ADPKD GFR >60 = 24%, ADPKD GFR 25– 60 = 24%). There were no differences in AIx, sICAM, p-selectin, e-selectin, or FasL between the two ADPKD groups (Table 1

, p>0.05).

Conclusion:
Vascular dysfunction and vascular inflammation are evident even in early stages of ADPKD with preserved GFR. Further research is needed to examine the relative contributions of genetic aberrations, hypertension, and reduced kidney function to the pathophysiology of vascular dysfunction in ADPKD.

Table.

Subject information.
Abstract 5276: Insulin-like Growth Factor I Downregulates Vascular Smooth Muscle and Macrophage 12/15-Lipoxygenase Expression: Potential Mechanism for Igf-1-induced Atheroprotection.
Authors: Vaughn Charlotte , Sukhanov Sergiy , Shai Shaw-Yung , Higashi Yusuke , Delafontaine Patrick
Published: April 2024

We have shown that IGF-1 infusion in ApoE−/− mice reduces atherosclerosis. To define mechanisms we performed RT-PCR gene arrays and found that IGF-1 (1.8 mg/kg/d, i.p., 1w, n=6) markedly reduces aortic 12/15-lipoxygenase (LOX) expression (64±6% decrease, P<0.05). LOX plays a major role in oxidation of native LDL to its pro-atherogenic form (OxLDL) and is expressed in vascular smooth muscle cells (SMC) and macrophages (MΦ). DHE staining in situ revealed increased superoxides in atherosclerotic plaque of ApoE−/− mice (77±6% increase vs. adjacent media, P<0.05) correlating with increased MΦ infiltration and LOX expression. A LOX-specific inhibitor baicalin (50
μ
M) dramatically suppressed plaque superoxides (59±8% inhibition, P<0.01), consistent with LOX being a major source of superoxides. IGF-1 infusion in ApoE−/− mice (1.5 mg/kg/d, 12 w, western diet, n=12) markedly reduced aortic plaque LOX immunopositivity (74±9% decrease, P<0.05), superoxide levels (84±7%, P<0.05) and atherosclerotic lesion size (IGF-1: 0.259±0.018
μ
m2 saline: 0.356±0.331
μ
m2, 28% decrease, P<0.05). To obtain insight into the relative role of SMC vs. MΦ LOX in IGF-1 induced atheroprotection we generated SMP8/ApoE−/− mice in which IGF-1 is overexpressed in SMC. SMP8/ApoE−/− mice (western diet, 12w) had decreased aortic LOX expression (71% decrease vs. ApoE−/− mice, P<0.05, n=5) but no reduction in atherosclerosis suggesting that the ability of increased circulating IGF-1 to reduce atherosclerosis was primarily mediated via its effect on MΦ LOX. To further define mechanisms and to model
in vivo
conditions, SMC or THP-1 derived MΦ were exposed to OxLDL (80ug/mL, 16h) with/without IGF-1. OxLDL markedly increased LOX activity in MΦ and SMC (18-fold vs. nLDL), however, pre-treatment with IGF-1 completely abolished OxLDL-induced LOX activation only in MΦ. In summary, IGF-1 infusion markedly reduces plaque LOX levels and decreases atherosclerotic plaque burden, but SMC-specific IGF-1 over expression reduces LOX but does not alter atherosclerosis. Taken together with our finding that IGF-1 markedly inhibits OxLDL-induced LOX activation in MΦ in vitro our data suggests that IGF-1 downregulation of MΦ LOX activity plays an important role in reducing atherosclerotic plaque burden.
Abstract 5278: Essential Role of the Rho Exchange Factor Arhgef1 for Angiotensin II-induced RhoA/Rho Kinase Activation and Arterial Tone Regulation
Authors: Guilluy Christophe , Brégeon Jérémy , Toumaniantz Gilles , Rolli-Derkinderen Malvyne , Scalbert Elizabeth , Bril Antoine , Pacaud Pierre , Loirand Gervaise
Published: April 2024

Rho exchange factors (Rho-GEFs) are signaling molecules responsible for Rho protein activation by catalyzing the exchange of GDP for GTP. Although over-activation of the small G protein RhoA and its effector Rho kinase is recognized as a critical component of the pathogenesis of hypertension in experimental models and in human, the molecular mechanisms and the RhoA-GEF(s) involved in this activation of RhoA signaling in vascular smooth muscle cells (VSMCs) are still unknown. Nevertheless, angiotensin II (Ang II) has been shown to play a key role in the over-activation of RhoA in hypertension. Here we identify the RhoA-GEF and the molecular mechanism responsible for the activation of RhoA and Rho kinase in response to Ang II type 1 receptor activation (AT1R) in rat aortic VSMCs. Systematic functional analysis by siRNA-mediated silencing of the 28 RhoA GEFs indicated that only Arhgef1 (p115, lsc) is involved in Ang II (0.1
μ
M)-mediated RhoA/Rho kinase activation. Knock-down of Arhgef1 had no significant effect on the activation of RhoA/Rho kinase induced by the thromboxan analog U46619, endothelin-1 and noradrenaline. The potency and efficacy of noradrenaline, phenyl-ephrine, U46619 and endothelin-1 to elicit contraction of rat aortic rings were not modified by Arhgef1 silencing whereas the contractile effect of Ang II was abolished. Ang II-induced Arhgef1 activation was further confirmed by
in vitro
guanine nucleotide exchange assay on RhoA, and we demonstrated by the transfection of Arhgef1 mutants that Ang II-induced Arhgef1 activation was due to its phosphorylation on Tyr738 by the tyrosine kinase Jak2. To confirm the functional role of Arhgef1 in Ang II-mediated regulation of vascular tone and hypertension, we then determined the activity of Arhgef1 in arteries from Ang II treated rats by pull-down assay. Chronic infusion of Ang II (250 ng/kg/min, 14 days) through an osmotic minipump induced an increase in arterial pressure associated with enhanced RhoA/Rho kinase activity and activation of Arhgef1 in arteries. Our results thus show that Arhgef1 activation and its downstream RhoA signaling are essential for Ang II-induced contraction and identify Arhgef1 as a potential specific target for the treatment of Ang II-dependent hypertension.
Abstract 5279: GIT1 is Required for Neointima Formation by Regulating Notch1 Signaling Pathway
Authors: Pang Jinjiang , hoefen Ryan , Hur Min , Michaloski Heidi , Mohan Amy , Berk Bradford C
Published: April 2024

Notch1 is a critical regulator of cell fate, angiogenesis and cardiovascular development. Upon ligand (Delta and Serrate/Jagged) binding, Notch1 is proteolytically cleaved by
γ
-secretase to generate the Notch intracellular domain (N1-ICD). N1-ICD translocates to the nucleus to stimulate target gene expression. Recently it was shown that Notch1 mediates vascular smooth muscle cell (VSMC) proliferation and neointimal formation after vascular injury. G-protein-coupled receptor-kinase-2 interacting protein 1 (GIT1), is a multi-domain scaffold protein, that plays an important role in angiotensin II (AngII) induced Ca(2+)-calmodulin (CaM)-dependent kinase II (CaMKII) activation. It has been shown that AngII stimulates VSMC growth through CamKII-Akt pathway. Activation of Akt increases
γ
-secretese activity and subsequently increases Notch1 cleavage. Our hypothesis is that knockdown of GIT1 will impair the activation of CamKII-Akt pathway, which will decrease Notch1 cleavage, and subsequently decrease neointima formation. Stimulation of VSMC with AngII time- dependently caused Notch1 cleavage, N1-ICD formation, and
Hey1
expression. VSMC treated with AngII and GIT1 siRNA showed dramatic decreases in Notch1 cleavage and Akt activation. Since Notch 1 is important for cell proliferation and survival, knockdown of GIT1 may inhibit cell proliferation and increase cell apoptosis. Serum-stimulated growth was decreased by 60% in GIT1 KO VSMC compared to WT VSMC. Moreover, apoptosis induced by serum derivation in GIT1 KO VSMC increased 2-fold compared with WT VSMC. Cyclin D1, which is a key regulator of cell cycle, was significantly decreased in GIT1 KO VSMC. Finally to confirm the physiological role of GIT1 in VSMCs in vivo, complete carotid ligation was performed in GIT1 WT and KO mice. After carotid ligation, GIT1 expression in vessels of WT mice increased. Intimal and medial hyperplasia after 4 weeks was markedly decreased in GIT1 knockout mice. In conclusion, GIT1 plays a crucial role in VSMC proliferation and survival by regulating Notch1 activation, thereby regulating flow-mediated vascular remodeling and intima formation.

This research has received full or partial funding support from the American Heart Association, Founders Affiliate (Connecticut, Maine, Massachusetts, New Hampshire, New Jersey, New York, Rhode Island, Vermont).