bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 175: Efficacy of Biomimetic Peptide-Fluorosurfactant Polymer Coated Expanded Poly(tetrafluoroethylene) Vascular Grafts in a Porcine Carotid Artery Interposition Model
Authors: Bastijanic Jennifer M , Dudash Lynn A , Kligman Faina , Allemang Matthew T , Lakin Ryan O , Eslahpazir Benjamin A , Kashyap Vikram S , Kottke-Marchant Kandice , Marchant Roger E
Published: March 2022

Objectives

Vascular grafts currently see limited use in small diameter applications due to the prevalence of thrombosis. Patency of ePTFE grafts could be improved by reducing thrombosis via an endothelial cell specific peptide fluorosurfactant polymer (FSP) coating.

Methods

In this study, ePTFE grafts were coated with cRRE-FSP, RGD-FSP, or Maltose-7 (M7)-FSP, sodded with porcine pulmonary artery endothelial cells (PPAECs), and evaluated in vivo in a porcine carotid artery interposition model. Grafts were excised after one month and evaluated by quantifying thrombosis and intimal hyperplasia and by qualitatively examining inflammation, smooth muscle cell infiltration, and endothelialization.

Results

Angiography of the grafts after one month showed at least partial patency in all grafts with the exception of one RGD-coated and one uncoated graft. Immunofluorescent staining of cell-sodded grafts showed a complete endothelial layer of adherent and spread PPAECs. Thrombus formation was present in two uncoated grafts and one RGD-coated graft. Intimal hyperplasia comprised mostly of smooth muscle cells was present in all grafts, but developed to the highest extent in RGD-coated grafts. Mean graft occlusion in M7 (24.7%) and cRRE-coated grafts (25.1%) was reduced by half compared to uncoated (58.5%) and RGD-coated grafts (53.9%).

Conclusions

Increased intimal hyperplasia in RGD grafts suggests that RGD, a prominent cell adhesion peptide, may facilitate ingrowth of more smooth muscle cells compared to the other grafts. These results show that cRRE-FSP coating of ePTFE grafts may reduce thrombosis, making it a promising candidate for improving graft patency.
Abstract 176: The Edge Effect: How Syndecan-1 Can Increase the Therapeutic Efficacy of Vasoregulatory Drugs and Growth Factors
Authors: Chaterji Somali , Gaddam Neha G , Atyam Neha , Ho Derek S , Baker Aaron B
Published: March 2022

Rationale

Vascular smooth muscle cells (vSMCs) in mature animals normally reside in a quiescent state, expressing a distinct combination of contractile proteins, ion channels, and signaling molecules. However, in cases of vascular disease and injury, vSMCs are capable of being activated, shifting their phenotype through a continuum of cell fates. While the heparan sulfate proteoglycans syndecans, residing at cellular edges as transmembrane receptors, have emerged as powerful and complex regulators of cell function, their role in intercepting growth factors and therapeutic molecules modulating vSMC phenotype is unknown.

Objective

The purpose of this study was to examine the role of syndecan-1 in modulating the vSMC phenotype in the context of endogenous factors and drug treatments used for vascular disease.

Methods and Results

vSMCs were isolated from wild type (WT) and syndecan-1 knockout (S1KO) mice and cultured in different biochemical environments. Gene and protein expression studies indicated decreased α-smooth muscle actin (α-SMA) and calponin levels in S1KO cells relative to WT under simulated inflammatory conditions. Rapamycin treatment reversed the reduction in expression caused by S1KO, suggesting that the effects were, in part, mediated through mTORC1 signaling. In addition, S1KO vSMCs expressed higher levels of tissue factor, IL-6, and VCAM-1. These differences were maintained under treatment with heparin and TGF-β1, PDGF-BB, or atorvastatin. In-vivo studies with aortae from aged WT and S1KO mice indicated that S1KO arteries stained significantly lower for calponin.

Conclusions

Our findings not only provide insights into the fundamental cell surface receptors responsible for vSMC differentiation but also identify that the loss of syndecan-1 can make vSMCs more vulnerable to inflammatory molecular signals and potentially cause resistance to treatment with rapamycin and atorvastatin. Thus, preservation or enhancement of syndecan-1 expression may be a potential therapeutic target for altering the course of in-stent restenosis and atherosclerosis.
Abstract 178: Platelet Cd40 Exacerbates Atherosclerosis by Transcellular Activation of Endothelial Cells and Leukocytes
Authors: Lievens Dirk , Seijkens Tom , Kuijpers Marijke J , Winkels Holger , Hartwig Helene , Beckers Linda , Megens Remco T , Boon Louis , Noelle Randolph J , Gerdes Norbert , Heemskerk Johan W , Soehnlein Oliver , Weber Christian , Lutgens Esther
Published: March 2022

Beyond their eminent role in hemostasis and thrombosis, platelets are recognized as mediators of inflammation and protagonists of atherogenesis. Here we investigated the inflammatory propensity of platelet-specific expression of CD40, the most common receptor for CD40L. Besides its presence on immune cells and other cell types, CD40 is constitutively expressed on platelets where its function is largely unknown.

CD40-deficient platelets exhibited impaired thrombin-induced activation, reflected by decreased P-selectin expression and αIIbβ3 integrin activation. Compared to infusion of activated Apoe-/- platelets, injection of activated Cd40-/-Apoe-/- platelets caused a >2-fold decrease in plaque size in the aortic arch (Apoe-/- platelets 18.3x104 ± 2.7x104 μm2 vs Cd40-/-Apoe-/- platelets 6.7 x104 ± 2.1 x104 μm2, Vehicle 9.8 x104 ± 2.8 x104 μm2, p<0.05) of Apoe-/- mice. Intravital microscopy of carotid arteries revealed impaired platelet adhesion and impeded leukocyte recruitment to the arterial wall of mice injected with activated Cd40-/-Apoe-/- platelets, which was accompanied by a decrease in endothelial VCAM-1 expression. Moreover, Cd40-/-Apoe-/- platelets displayed a reduced capacity to form platelet-leukocyte aggregates in vitro with these co-incubations releasing less IL-1β. Interestingly, once a thrombus had formed, leukocyte recruitment into thrombi was hampered in Cd40-/-Apoe-/- thrombi.

This study ascribes an essential function to platelet CD40 in atherosclerosis. Besides platelet activation, platelet CD40 induces activation of leukocytes and endothelial cells, thereby promoting inflammation and consequently atherogenesis.
Abstract 184: Sirt3 is a Critical Mediator of Diet-induced Vasomotor Dysfunction
Authors: Roos Carolyn M , Fujimoto Hirokazu , Zhang Bin , Miller Jordan D
Published: March 2022

Increases in mitochondrial reactive oxygen species (ROS) can contribute to endothelial dysfunction in conduit arteries by reducing nitric oxide bioavailability. SIRT3 is a protein deacetylase localized to mitochondria and regulates activity of numerous electron transport chain enzymes, and can be inactivated by increases in mitochondrial ROS. Whether reductions in SIRT3 are an independent contributor to endothelial dysfunction, however, are unknown. Therefore, we hypothesized that SIRT3 null mice (SIRT3
-/-
) will have impaired relaxation to acetylcholine (MR
Ach
) compared to wild-type littermates (SIRT3
+/+
), and that this difference will be exacerbated by Western diet feeding for 3 months (TD88137, 42% of kcal from fat, 0.2% cholesterol). Endothelial function was measured using isolated organ bath chambers, and endothelium-dependent (MR
Ach
) and endothelium-independent (sodium nitroprusside, MR
SNP
) relaxation were measured. In contrast to our hypothesis, MR
ACH
was virtually identical between SIRT3
+/+
and SIRT3
-/-
fed a standard chow diet (MR
ACH
= 68±2% and 69±3%; respectively), and MR
SNP
also remained unchanged between the two genotypes. In groups fed a Western diet, however, endothelium-dependent relaxation was significantly impaired in SIRT3
-/-
mice compared to SIRT3
+/+
littermates (MR
ACH
= 49±4% and 58±3%, respectively; p<0.05). MR
SNP
was not altered by either Western diet feeding or SIRT3 deficiency. Interestingly, impairments in MR
Ach
in SIRT3
-/-
mice fed a Western diet were not rescued with acute incubation of apocynin (an NAD(P)H oxidase inhibitor) or mito-tempol (a mitochondria-targeted antioxidant), suggesting that chronic antioxidant and/or acetyltransferase inhibition may be required to improve vasomotor function in this model. Collectively, our data suggest that SIRT3 plays a major role in regulating endothelial function with dietary stress, and may be a useful therapeutic target to reduce cardiovascular risk.
Abstract 193: Chronic Inhibition of Tumor Necrosis Factor-alpha Slows Progression of Aortic Valve Stenosis in Mice
Authors: Kafa Rami , Roos Carolyn M , Oehler Elise , Zhang Bin , Hagler Michael A , Miller Jordan D
Published: March 2022

Introduction

While progression of calcific aortic valve stenosis (CAVS) is known to be strongly associated with activation of pro-inflammatory and pro-osteogenic pathways, effective treatments for CAVS have remained elusive. TNF-α is a pleiotropic inflammatory cytokine and is upregulated in patients with CAVS. Hence, we hypothesized that TNF-α inhibition, using the neutralizing antibody infliximab, can slow the progression of CAVS
in vivo
.

Methods

We used

Ldlr
-/-
Apob
100/100

mice, which develop robust CAVS in an age-dependent manner, as a model. Mice were fed a Western-type diet for 6 months, then randomized into one of two groups: 1) twice-weekly infliximab injections (10 mg/kg intraperitoneally; n=10), and 2) saline injections (n=9). Aortic valve function was evaluated using echocardiography, and gene expression in aortic valves was measured using quantitative real-time PCR. Data are presented as mean ± SEM.

Results

During the 3 months preceding treatment initiation, aortic valve cusp separation distance decreased progressively in both groups (reduction by 0.082±0.011 mm in control group, 0.095±0.016 mm in infliximab group;
p
=0.27). Three months after initiation of treatment, cusp separation continued to decrease in control mice (by 0.108±0.021 mm), while progression of valve dysfunction was slower by 42% in the infliximab group (reduction of 0.063±0.009 mm;
p
=0.03 vs control). Expression of the pro-inflammatory genes
Vcam1
and
Nos2
was significantly reduced in valves of the infliximab group (by 37% and 60%, respectively). Moreover, endothelium-dependent vasodilation was improved by infliximab (improvement in maximum relaxation to acetylcholine in infliximab group 18±6% compared to control).

Conclusions

This study is the first to report that
in vivo
inhibition of TNF-α slows progression of CAVS in mice with established valve disease. This beneficial effect was accompanied by reduction in pro-inflammatory gene expression and improvement of systemic endothelial function, suggesting infliximab may exert its effects in part by increasing nitric oxide bioavailability. The findings warrant further investigation into the role of TNF-α in initiation and progression of CAVS, as well as its potential as a therapeutic target in human CAVS.
Abstract 195: Apolipoprotein E Suppresses Atherosclerosis by Reducing Th1 Inflammatory Responses and by Favorably Altering Aortic Dendritic Cell Subsets in Hyperlipidemic Mice
Authors: Li Kang , Luk Fu Sang , Kumar Nikit , Kim Roy Y , Mahne Ashley , Eberle Delphine , Rapp Joseph H , Tang Qizhi , Raffai Robert L
Published: March 2022

Apolipoprotein (apo) E can suppress atherosclerosis by regulating myeloid cell proliferation and monocyte activation. However, little is known about its capacity to regulate adaptive immunity. To explore this question, we studied our recently described HypoE mice deficient in the LDL receptor (Apoeh/hLdlr−/− mice) that spontaneously develop a hyperlipidemia similar to that of Apoe-/-Ldlr-/- mice when fed a chow diet, but accumulate apoE in plasma and display reduced atherosclerosis. Twenty-week old Apoeh/hLdlr-/- mice (n=10) displayed smaller spleen and lymph nodes that contained fewer leukocytes (p<0.05) and (p<0.0001) respectively compared to Apoe-/-Ldlr-/- mice (n=8). Both myeloid-derived and lymphoid-derived cell counts were decreased in the spleen of Apoeh/hLdlr-/- mice. Further analysis showed that both the spleens and lymph nodes of Apoeh/hLdlr-/- mice had a higher percentage of T cells that displayed a naïve phenotype (CD44lowCD62Lhigh) compared to Apoe-/-Ldlr-/- mice. In contrast, the percentage of memory effector T cells (CD44highCD62Llow) was decreased in Apoeh/hLdlr-/- mice. Intracellular cytokine analysis showed that both CD4+ (p<0.01) and CD8+ (p<0.05) T cells in spleens derived from Apoeh/hLdlr-/- mice produced 50% less IFN-γ than those of Apoe-/-Ldlr-/- mice. Reduced T cell activation and Th1 differentiation did not derive from enhanced Foxp3+ regulatory T cell (Tregs) function as the frequency and suppressive function of Tregs isolated from Apoeh/hLdlr-/- mice and Apoe-/-Ldlr-/- mice were similar at that time point. In marked contrast, DCs isolated from spleens of Apoeh/hLdlr-/- mice showed less expression of the co-stimulatory molecule CD86 compared to those of Apoe-/-Ldlr-/- mice. We also observed a significant decrease in both T cell (p<0.05) and DC numbers (p<0.01) in digested aortas of Apoeh/hLdlr-/- mice compared to those of Apoe-/-Ldlr-/- mice. Interestingly, aortic DCs derived from Apoeh/hLdlr-/- mice displayed a lower percentage of the pro-inflammatory CD11b+ subtype but a higher percentage of the anti-inflammatory CD103+ subtype. Collectively, our findings provide the first in-vivo evidence that apoE can suppress T cell activation and favorably alter DC subsets in the aorta of hyperlipidemic mice.
Abstract 200: Geographical Location and Gender are Predictors of Elevated High Sensitive C-Reactive Protein (hsCRP) Levels and the Levels Strongly Correlate with Metabolic Syndrome (MetS) in a South Asian Population
Authors: Thanikachalam Mohan , Harivanzan V , Baliga Ragavendra R , Abraham William T , Thanikachalam Sadagopan
Published: March 2022

Background

hsCRP is a risk factor for MetS. However, the distribution of hsCRP levels and its association with MetS in South Asians is unclear.

Methods

We conducted a population-based cross-sectional survey in 8,042 Indians (44% males, 56% females), age ≥20 yrs in urban (n=5, 017) and rural (n=3,025) communities. The study included anthropometric measurements, and fasting blood for plasma glucose, hsCRP and lipids. MetS was defined using NCEP (ATP III) criteria for Asians.

Results

The median hsCRP level was 2.30 mg/l [95% confidence interval (CI) 2.24, 2.39]. Adjusting for age and BMI, the hsCRP level was significantly higher in women, median 2.86 [CI 2.73, 2.97] when compared to men, median 1.80 [CI 1.71, 1.88] (p-value < 10-9). Adjusting for gender, age & BMI the urban communities had significantly higher hsCRP levels versus rural (p-value = 0.03). The fig. shows the distribution of hsCRP according to the number of components of MetS. The median hsCRP for those with 0, 1, 2, 3, 4, and 5 features of MetS are 1.01, 1.47, 2.3, 3.19, 3.70 and 3.94, respectively. Based on Kruskal-Wallis H test, after adjusting the hsCRP for gender, age and community, hsCRP levels were significantly higher in individuals with more components of MetS (p-value < 10-9 for trend). hsCRP and BMI were relatively independent predictors of MetS. Prevalence of MetS was higher in women (prevalence ratio [PR] = 1.15; CI 1.09, 1.21) and in urban communities (PR = 1.47; CI 1.35, 1.66).

Conclusions

hsCRP is highly associated with the MetS and the number of positive MetS components. Geographical location and gender are predictors of hsCRP levels, which is associated with a higher incidence of MetS in urban communities and women.
Abstract 201: Transfer of Intracellular HIV-Nef to Endothelium Causes MCP-1 Release and Induction of Apoptosis
Authors: Wang Ting , Green Linden , Gupta Samir , Clauss Matthias
Published: March 2022

With effective antiretroviral therapy (ART), cardiovascular diseases (CVD) are emerging as a major cause of morbidity and death in the aging HIV-infected population. To address whether HIV-Nef, a viral protein produced in infected cells even when virus production is halted by ART, can lead to endothelial activation and dysfunction, we tested Nef protein transfer to and activity in endothelial cells. We demonstrated that Nef protein from either HIV-infected or Nef-transfected T cells rapidly transfers to endothelial cells while inducing nanotube-like conduits connecting T cells to endothelial cells. This transfer to or transfection of endothelial cells resulted in apoptosis, ROS generation and release of monocyte attractant protein-1 (MCP-1). Nef-induced apoptosis is mediated through both NADPH oxidase- and ROS-dependent mechanisms, while MCP-1 production is NF-κB dependent. Importantly, Nef protein can be found in circulating blood cells in patients receiving virally suppressive ART, and in the endothelium of chimeric SIV-infected macaques. Together, these data indicate that inhibition of Nef-associated pathways may be promising new therapeutic targets for reducing the risk for cardiovascular disease in the HIV-infected population.
Abstract 220: Shear Stress Induces the Expression of Connexin-43 in Human Coronary Smooth Muscle
Authors: Shaw Jennifer H , Rashdan Nabil , Lloyd Pamela G
Published: March 2022

Coronary collaterals normally do not accommodate blood flow unless an upstream occlusion diverts blood flow through them. This blood flow provides an initiating stimulus, shear stress on the vessel wall, to increase collateral vessel diameter and wall thickness. This process, termed arteriogenesis, requires chemoattraction of monocytes into the vessel wall and vascular smooth muscle proliferation. Therefore, communication of the shear signal from the endothelium to the underlying smooth muscle is necessary. Previously, we demonstrated that endothelial cells exposed to shear stress release hydrogen peroxide which signals the underlying smooth muscle to express the arteriogenic factor, placenta growth factor (PLGF). Additional signaling pathways are involved in arteriogenesis although the mechanisms of communication across the vessel wall and regulation are still largely unknown. Connexins (Cx) are transmembrane proteins that form hemichannels between cells which enable direct exchange of signaling molecules. Vascular connexins have been shown to modulate blood flow, angiogenesis, and are correlated with atherosclerosis; however, very little is known of their role in arteriogenesis, particularly in human coronary vasculature. In this study, human coronary artery endothelial cells (CAEC) were co-cultured on membranes with coronary artery smooth muscle cells (CASMC) to mimic the vessel wall structure. We hypothesized that co-cultures exposed to high shear stress would exhibit an altered expression pattern of vascular connexins relative to static and normal shear stress. We show that 2 h of high shear stress at the endothelial surface significantly increases (3 fold) the expression of Cx43 in coronary smooth muscle while Cx37 and Cx40 are undetectable under static and shear conditions. Shear stress did not drive a significant change in the expression of Cx37, Cx40, or Cx43 in coronary endothelial cells compared to static conditions. Taken together with our previously published work, the data suggest that expression of Cx43 by human coronary smooth muscle may play a role in shear signaling pathways for arteriogenesis.
Abstract 229: Protein Kinase D-1 Regulates CD36 Transcription and Arteriogenic Differentiation of Endothelial Cells
Authors: Ren Bin , Chen Yiliang , Best Brad , Kohlenberg Jacob D , Storz Peter , Peterson Randall T , Silverstein Roy
Published: March 2022

CD36 is a microvascular endothelial cell (MVEC) receptor mediating angiostatic activity of TSP-1 and related proteins. We previously reported that lysophosphatidic acid (LPA), a biologically active lipid signaling mediator, inhibited MVEC
CD36
transcription via PKD-1 signaling. Moreover,
CD36
transcriptional repression abolished endothelial cell responses to TSP-1
in vitro
and
in vivo
. We now show with luciferase transfection assays that LPA exposure significantly suppressed CD36 promoter activity in MVEC. Co-exposure to class II HDAC inhibitors SAHA or TSA reversed the inhibition of promoter activity and restored transcription. HDAC7 knockdown by shRNA also attenuated LPA-suppressed CD36 promoter activity and mRNA levels. Mechanistically, FoxO1 was found to directly interact with putative FoxO1 binding sites (FHRE) in proximal promoter
in vitro
by avidin-biotin-conjugated DNA-binding assay, and
in vivo
by chromatin IP assay. Furthermore, FHRE mutations significantly attenuated the promoter activity. Western blots and immunofluorescence microscopy showed increased nuclear accumulation of PKD-1, FoxO1 and HADC7 after MVEC were exposed to LPA. Co-IP of nuclear extracts showed a physical interaction of HDAC7 with FoxO1 that was attenuated with PKD-1 knockdown. These data demonstrate that HDAC7 modulation by LPA receptor/PKD-1 signaling pathway represses FoxO1-mediated CD36 transcriptional activity. Additionally, angiogenic transcription profiling of endothelial cells revealed significantly increased mRNA expression of 17 angiogenic genes in response to LPA, including ephrin B2 expression that was confirmed by Western Blots. Transduction of constitutively active PKD-1 (PKD-CA) into EC also increased ephrin B2 expression. Functionally, PKD-CA overexpression promoted branching morphogenesis of arterial endothelial cells in a three-dimensional spheroid assay. The data indicate that PKD-1 is a potent angiogenic and arteriogenic kinase in EC by down-regulating CD36 transcription and promoting arteriogenesis. PKD-1-FoxO1-CD36 signaling axis may have potential as an important target in cardiovascular ischemia and malignant tumors.
Abstract 233: Endotension: Net Flow through an Endoleak Determines its Visibility
Authors: Blackwood Stuart , Mix Doran , Wingate Mallory , Chandra Ankur , Dietzek Alan
Published: March 2022

OBJECTIVES

Unexplained aneurysm growth despite multimodality imaging following EVAR is often attributed to endotension. We tested a hypothesis that endotension may be from a type 1a endoleak (EL) pressurizing the aneurysm sac without net forward flow, not visualized on standard angiographic imaging.

METHODS

A patient-specific aortic aneurysm phantom was constructed of polyvinyl alcohol using 3D molding techniques. A bifurcated stent graft was implanted and the phantom connected to a hemodynamic simulator for testing. Type 1a ELs were created using 7 Fr catheters. Three scenarios were studied: complete exclusion (no EL); inflow with no sac outflow; and inflow with sac outflow. DSA imaging was performed at 48kvP at 5fps followed by delayed imaging (1 frame/min) over 30 minutes.

RESULTS

With no EL, the systemic MAP (sMAP) averaged 113mmHg and Aneurysm Sac MAP (asMAP) averaged 101mmHg. (Table 1) With EL without outflow, the sMAP averaged 116mmHg and asMAP averaged 120mmHg. EL flow was bidirectional with no net forward flow. With EL with aneurysm sac outflow, the sMAP averaged 119mmHg, asMAP averaged 105.5mmHg and net EL flow was +21cc/min across the EL channel. With DSA imaging, the EL with no outflow was noted after >9 min of delayed imaging.

CONCLUSIONS

Our model demonstrated a Type Ia EL in the absence of aneurysm sac outflow resulting in full pressurization of the aneurysm sac with biphasic (zero net) flow. This EL was not visible on standard contrast DSA until >9 min. This model may serve as a first step in explaining both the mystery of endotension and in vivo aneurysm sac growth with no detectable ELs using current standard imaging modalities.
Abstract 248: Role of Mitochondrial Heat-Shock Protein 90 (HSP90) in Regulation of Vascular Smooth Muscle Cell (VSMC) Apoptosis and Vascular Remodeling in-vivo
Authors: Runge Sara , Chen Mian , Chatterjee Anuran , Miyahara Takuya , Altieri Dario , Conte Michael
Published: March 2022

Introduction

Apoptosis of VSMC is a common feature of vascular remodeling. Mitochondrial apoptosis is regulated by an organelle-specific network including Hsp90 family proteins. Gamitrinib (G4) is a small molecule that selectively targets mitochondrial Hsp90 and has shown antitumor activity. We investigated the effects of G4 on mitochondrial membrane potential (MMP) and apoptosis in VSMC, and on vascular remodeling in vivo.

Methods

Primary cultured human VSMCs were treated with G4, 17-AAG (inhibits cytosolic Hsp90), or vehicle. MMP (TMRM assay), apoptosis (Annexin V/PI flow cytometry) and cell viability (MTT assay) were measured. For in vivo studies, a mouse carotid artery ligation model was used. Mice (N= 45) were treated with systemic G4 (10 mg/kg IP daily) vs. control, and sacrificed at 3 or 14 days.

Results

Pre-treatment of VSMC with G4 (1 uM) resulted in a rapid, dose-dependent loss of MMP upon exposure to peroxynitrite (PN;25-200 uM), compared to 17-AAG or vehicle. G4 (25 uM) sensitized VSMC to apoptotic death (17.5% vs 8.8%, p=.02) following exposure to PN (300 uM, 4 hrs). In-vivo, G4 treatment resulted in increased apoptosis (TUNEL) in the ligated carotid artery (21% vs 4 %, p=.02) at 3 days, with no discernible difference in proliferation (Ki67 and BrdU). At 14 days, G4 treatment resulted in improved remodeling, with reduced intimal thickness (25%, p=.04) and increased radius:wall thickness ratio (50%; p=.008; Figure).

Conclusions

Selective targeting of mitochondrial Hsp90 sensitizes VSMC to mitochondrial depolarization and apoptosis, and alters vascular remodeling in-vivo. This may represent a new molecular target to modulate vascular injury.
Abstract 252: Method to Quantify Femoropopliteal Artery Deformation During Knee Flexion
Authors: Kamenskiy Alexey V , Lomneth Carol S , Pipinos Iraklis I , Longo G. Matthew , Johanning Jason M , Baxter B. Timothy , MacTaggart Jason N
Published: March 2022

Introduction

High failure rates of femoropopliteal reconstructions are commonly attributed to deformations and forces exerted on the artery during movement. The purpose of this study was to develop a method to better quantify these deformations.

Methods

Custom-made stainless steel markers were deployed in an
in situ
cadaveric femoropopliteal artery. The artery was then infused with contrast and CT images of the straight and bent (45°, 90°, 135°) leg were acquired. 3D reconstructions of the leg were created using Mimics and identification of the marker position and geometry enabled measurements of axial extension, compression, bending and torsion. After imaging, the artery was surgically exposed, photographed and excised for histological analysis.

Results

The femoropopliteal artery deformed non-uniformly along its length. No changes with knee flexion were seen proximal to the adductor hiatus and radial compression was minimal throughout the length of the artery. At the adductor hiatus the artery experienced 45° angle of twist, but no axial compression or bending. Distally, buckling and axial compression (36%) were demonstrated, but no torsion. Histology demonstrated intimal thickening corresponding to areas with the largest deformations (Figure 1).

Conclusions

This method allows quantification of non-uniform arterial deformation in the femoropopliteal artery with knee flexion. This information may assist in the design of better reconstruction techniques and devices for treatment of femoropopliteal arterial disease.
Abstract 276: Nicotine Infusion Fails to Induce Abdominal Aortic Aneurysmsin LDL Receptor Deficient Mice
Authors: Xu Yinchuan , Lu Hong , Howatt Deborah A , Balakrishnan Anju , Moorleghen Jessica J , Cassis Lisa A , Daugherty Alan
Published: March 2022

Background and Objective

Smoking is a major risk factor for the development of abdominal aortic aneurysms (AAA). Although there are a large number of chemical constituents of smoke, recent evidence demonstrated that nicotine infusion to apoE -/- mice induces AAA formation. These nicotine-induced AAAs share many characteristics to those formed during infusion of angiotensin II (AngII). The purpose of this study was to contrast the susceptibility of AAAs induced by nicotine versus AngII in LDL receptor -/- mice.

Methods and Results

Ten-week-old male LDL receptor -/- mice were fed a saturated-fat supplemented diet for 7 weeks. One week after the initiation of the fat-enriched diet feeding, mice were randomized into 3 groups: saline infusion (N = 5), AngII (1 μg/kg/min; N = 5) infusion, and nicotine (5 μg/kg/min; N = 10) infusion, respectively, for 6 weeks. Infusions were performed using mini-osmotic pumps implanted subcutaneously. Cotinine is the major metabolite of nicotine. Plasma concentrations of cotinine were undetectable in saline and AngII-infused mice, but were at detectable levels (87 ± 28 ng/ml) in nicotine-infused mice. Despite measurable plasma concentrations of cotinine, nicotine infusion had no effect on body weight, systolic blood pressure, plasma total cholesterol concentrations, and lipoprotein-cholesterol distribution. Also, we were unable to discern any nicotine-induced changes in the lumen diameter of suprarenal aortas in live mice using high frequency ultrasound or maximum width of suprarenal aortas (0.94 ± 0.02 mm) measured ex vivo after termination. In contrast, AngII infusion promoted aortic rupture (N = 2/5 = 40%) and profoundly increased maximal width of suprarenal aortas (1.83 ± 0.20 mm) compared to mice infused with saline (0.91 ± 0.04 mm).

Conclusion

In contrast to AngII, infusion of nicotine does not induce AAA formation in LDL receptor -/- mice.
Abstract 278: Protective Effects of Niacin in a Murine Model of Abdominal Aortic Aneurysms
Authors: Thompson Allie , Robbins Nathan , Mann Adrien , Chatterjee Tapan , Batra Neil , Weintraub Neal , Blomkalns Andra
Published: March 2022

Introduction.

Abdominal aortic aneurysms (AAAs) are common among the aging population, yet there is no effective pharmacotherapy. Neutrophils play a key role in the pathogenesis of AAA, by triggering inflammation, oxidative stress, matrix degradation and smooth muscle cell (SMC) death. Niacin, a vitamin with beneficial cardiovascular effects, was shown previously to reduce vascular neutrophil infiltration, MPO accumulation, and HOCl-induced endothelial dysfunction in a rabbit perivascular injury model.

Hypothesis

We hypothesized that niacin would have beneficial effects to prevent AAA in a mouse model.

Methods

LDL null mice were infused with angiotensin II (1000 ng/kg/min) for 14 days to induce AAA with (n=27) or without (n=18) 0.3% supplemental niacin in the drinking water. One group (n=6) received the DP1 receptor antagonist, laropiprant, in addition to niacin. We also investigated the effects of niacin on MMP release in a human neutrophil cell line (HL-60) and on viability of a murine SMC line (MOVAS-1) challenged with 100μM H
2
O
2
.

Results

Niacin decreased the rate of AAA formation as compared to untreated control mice, 26% vs. 83%, respectively. In mice that survived the complete 14 day treatment period and did not die due to a ruptured AAA, the mean suprarenal aorta diameters were 1.20 mm (SEM 0.09) in niacin treated mice vs. 1.68 mm (SEM 0.12) in the control group, representing a niacin treatment effect of a 29% diameter decrease (p<0.5). Laropiprant did not have an effect on AAA formation, however did increase the blood pressure moderately. In HL-60 cells stimulated with TNF-α, niacin (10mM) decreased MMP 9 activity by 88% but had no effect on cell viability. In MOVAS-1 cells exposed to hydrogen peroxide, 10mM niacin had a protective effect, reducing cell death at 12 hours (50% dead cells with niacin + H
2
O
2
vs. 93% dead cells with hydrogen peroxide alone, p=0.02).

Conclusions

We conclude that niacin decreases the incidence of AAA and demonstrates pleiotropic effects on neutrophils and SMCs that may underlie its already known beneficial lipid modifying mechanisms. These novel findings suggest that niacin might be a safe, effective and inexpensive medical therapy for AAA.
Abstract 295: Macrophages Induce Apoptosis of Arterial Smooth Muscle Cells via a Monocyte Chemoattractant Protein-1 (MCP-1) Mediated Cytotoxicity
Authors: Wang Qiwei , Morgan Stephanie , Ren Jun , Liu Bo
Published: March 2022

Objectives

Excessive apoptosis of smooth muscle cells (SMCs) has been observed in human and experimental abdominal aortic aneurysm (AAA). We have previously demonstrated in a murine model of AAA that apoptotic SMCs attract monocytes and other leukocytes by producing MCP-1. In this study, we hypothesized that MCP-1 may contribute to aortic destruction also by enhancing pro-apoptotic capability of infiltrating macrophages.

Methods and Results

In a co-culture system MCP-1 primed RAW264.7 macrophages caused significantly more apoptosis of SMCs compared to control macrophages (1.53±0.11 fold increase in % of Annexin V PE+/7AAD-/CD11b- cells, n=5, p<0.05). To understand how MCP-1 may modulate cytotoxicity, we treated RAW cells with MCP-1 and analyzed Fas Ligand (FasL) expression by real-time PCR and flow cytometry. MCP-1 enhanced FasL mRNA level by 1.60±0.15 fold (p<0.05, n=4) and membrane FasL expression by 1.62±0.20 fold (p<0.05, n=3). Neutralizing FasL blocked SMC apoptosis. Consistently, we found MCP-1 elevated levels of cleaved caspase 8 and 3 in SMCs exposed to MCP-1 primed macrophages. We hypothesize that MCP-1 primed macrophages kill SMCs through a FasL-Fas-Caspase8- receptor interacting protein-1 (RIP1) mediated mechanism. Silencing RIP1 conferred apoptosis resistant to SMCs, protected them from being killed by macrophages. In situ proximity ligation assay showed that the exposed SMCs contained higher levels of RIP1-Caspase 8 complexes. In the mouse elastase injury model of aneurysm, immuno co-staining showed that TUNEL-positive SMCs were frequently surrounded by CD68+ macrophages, although little engulfing activity was observed. In parallel, aneurysm induction increased the level of RIP1-Caspase 8 complexes in medial SMCs, indirectly proved the occurrence of FasL mediated-kill of SMCs during aneurysm development.

Conclusions

Taken together, our data suggest that MCP-1 not only attract monocytes/macrophages but also can modulate their function. Mechanistically, MCP-1 primes macrophages by increasing levels of membrane bound FasL. Since apoptotic SMCs release MCP-1 in large quantity, this newly described role of MCP-1 may indicate a positive feedback loop between residential SMCs and infiltrating macrophages.
Abstract 302: Smooth Muscle Cell Mineralocorticoid Receptors Directly Mediate Aldosterone-induced Remodeling After Vascular Injury Via Type 1 Vegf Receptors
Authors: Pruthi Dafina
Published: March 2022

Background and Significance

Endothelial damage initiates vascular remodeling with smooth muscle cell (SMC) proliferation and vascular fibrosis. Excessive remodeling, as in restenosis after vascular procedures or atherosclerosis, limits blood flow to distal tissues. In animals, aldosterone (aldo) infusion enhances remodeling which is reversed by aldo antagonists, implicating the mineralocorticoid receptor (MR). We previously showed that MR is expressed in SMC and that aldo induces the type 1 VEGF receptor (VEGFR1) in injured vessels.

Hypothesis and Results

We hypothesize that aldo promotes pathological vascular remodeling by directly activating MR in SMC and promoting SMC proliferation via VEGFR1 signaling. We show
in vivo
that aldo does not affect re-endothelialization after injury supporting our focus on SMC. To test this hypothesis we measured aldo-induced remodeling after wire carotid injury in mice with inducible SMC-specific deletion of MR (SMC-MR-KO). The 80% increase in SMC proliferation with aldo in control littermates is completely prevented in SMC-MR-KO mice (p<0.005, n=11). To examine the mechanism, mouse carotid SMC were treated with aldo
in vitro
producing a dose dependent proliferative response (1,5,10 and100nM aldo, 9%±2, 17%±3, 21%±6, and 25%±7 vs control, respectively, p<0.05, n=8). The increase in proliferation with 10 nM aldo+IgG was completely inhibited by treatment with specific VEGFR1-blocking antibody (Ab, p=0.04, n=8). Immunohistochemistry of carotid vessels reveals that VEGFR1 is induced in SMC after injury and further enhanced by aldo (55%±0.5 increase with injury, 74%± 0.5 with aldo+injury vs uninjured control, p<0.05, n=8).We examined the role of VEGFR1
in vivo
and VEGFR1 blockade significantly reduces aldo-induced SMC proliferation after injury (46%±4 decrease vs aldo+IgG, p<0.05, n=9). Tail cuff measurements reveal no difference in blood pressure with any of the treatments.

Conclusions

These data support that SMC MR directly mediates aldo-induced vascular remodeling independent blood pressure. The mechanism involves VEGFR1 that is induced on SMC in the area of injury. This study supports exploring VEGFR1-blocking drugs to prevent pathological vascular remodeling induced by aldo in humans.
Abstract 31: Vascular Repair by Adipose Stromal Fraction (SVF) cells in a Murine Model of Small Vessel Inflammation
Authors: Morris Marvin E , Reed Robert M , Williams Stuart K , Hoying Jay B
Published: March 2022

The relatively few therapeutic options for treating small vessel disease creates a significant clinical challenge. The stromal vascular fraction (SVF) derived from adipose tissue is a rich source of regenerative cells shown to have anti-inflammatory and vascular reparative capabilities. We explored the ability of these SVF cells to reverse vascular insult in a murine model of artery inflammation induced by the placement of a 2 mm long polyethylene cuff around the left femoral artery in male wildtype FVB/n mice. One week after cuffing, freshly isolated SVF cells harvested from syngeneic FVB/n
Tg(CAG-luc,-GFP)
mice ubiquitously and constitutively expressing the firefly luciferase and green fluorescent protein genes were injected via a tail vein. Sham mice, which underwent femoral exposure without receiving a cuff, were treated identically. Bioluminescence confirmed delivery and the persistent presence of SVF cells. Histological analysis of vessels indicated cuffed femoral arteries were surrounded by granulation tissue and exhibited intimal lesions associated with significant medial inward remodeling. In contrast, intravenous delivery of SVF cells after lesion formation, regardless of the dose, lessened intimal lesions, reversed medial remodeling, and reduced perivascular fibrosis. Immunostaining for luciferase identified SVF cells throughout the vessel wall and the surrounding extra-vascular tissue that were also positive for markers of M1 and M2 macrophages. In conclusion, intravenous delivery of freshly isolated adipose SVF cells reversed the vascular insult and peri-vascular granulation tissue due to inflammation.
Abstract 315: Caspase-1 Activation is Critical for Endothelial Cell Activation, Monocyte Recruitment, and Early Atherogenesis
Authors: Yin Ying , Wang Hong , Yang Xiao-Feng
Published: March 2022

Activation of caspase-1(Casp-1), an inflammatory protease in a protein complex termed inflammasome, has been demonstrated to play an essential role in sensing environmental and metabolic danger signals and initiating inflammation. Our goal of this study is to examine a novel hypothesis that Casp-1 activation in endothelial cells (ECs) plays a critical role in promoting EC activation and accelerating early atherogenesis. We first found that hyperlipidemia induced casp-1 expression and activation in mouse aorta along with atherogenesis in apolipoprotein E (ApoE)-/- mice with high fat (HF) diet feeding. By generating the ApoE-/-/Casp-1-/- mice, we then found that the deficiency of Casp-1 in ApoE-/- background significantly attenuated early atherosclerotic lesion formation in mouse aortic sinus (42% reduction comparing to that ApoE-/- mice (n=9)) when fed with a HF diet for 3 weeks. Mechanistically, we found that the ApoE-/-/Casp-1-/- mice had significantly less CD11b+/F4/80- monocytes (0.2% vs 0.4% in ApoE-/- mice(n=10)) and CD11b+/F4/80+ macrophages (0.9% vs 1.8% in ApoE-/- mice) infiltration into mouse aorta after 3-week HF diet. Moreover, we found that there were less cytokine and chemokine expressions in the aorta of ApoE-/-/Casp-1-/- mice in comparison to that of ApoE-/- mice. Furthermore, the deficiency of Casp-1 attenuated hyperlipidemia-induced EC activation by inhibiting adhesion molecules including intercellular adhesion molecule 1, vascular cell adhesion molecule 1 and E-selectin up-regulation both in mouse aorta and primary mouse aortic ECs. In in vitro experiments, we found that oxidized low density lipoprotein (ox-LDL) and two oxLDL active components, lysophosphatidylcholine and lysophosphatidic acid, induced Casp-1 activation through Reactive Oxygen Species pathway in human aortic ECs (HAECs). Finally, Casp-1 inhibitors attenuated oxLDL-induced monocyte adhesion to HAECs. Collectively, our data have demonstrated that Casp-1/inflammasome in ECs can sense hyperlipidemia and become activated, which drive EC activation and monocyte recruitment into aorta and promote early atherogenesis.
Abstract 325: Palmitic Acid Enhances the Stimulatory Effect of Lipopolysaccharide on Interleukin 6 Expression in Cardiac Microvascular Endothelial Cells by Increasing Ceramide Production via both De Novo Synthesis and Sphingomyelin Hydrolysis
Authors: Lu Zhongyang , Li Yanchun , Jin Junfei , Zhang Xiaoming , Huang Yan
Published: March 2022

Host inflammatory response mediated by toll-like receptor (TLR)4, a pattern recognition receptor for lipopolysaccharide (LPS), plays an important role in cardiovascular complication of diabetes. Although it is known that patients with type 2 diabetes or/and obesity have increased plasma free fatty acids (FAs), and saturated FAs such as palmitic acid (PA) increase host inflammatory response, the interaction between saturated FAs and LPS-elicited TLR4 signaling has not been well elucidated. Since it is known that neovascularization in advanced atherosclerotic plaques contributes to plaque destabilization, we investigated the mechanism whereby PA interacts with LPS for pro-inflammatory gene expression in cardiac microvascular (MIC) endothelial cells (ECs). We found that while LPS at 5 ng/ml stimulated a robust interleukin (IL)-6 secretion in cardiac MIC ECs, 100 μM of PA further augmented the stimulation by more than 2-fold (Control, 4.4; LPS, 41.3, PA, 6.0, LPS+PA, 89.0 ng/ml). Besides IL-6, PA also enhanced the stimulatory effect of LPS on tumor necrosis factor (TNF)α (Control, 2.6; LPS, 38.5, PA, 13.8, LPS+PA, 58.0 pg/ml). Time course study showed that IL-6 expression induced by LPS peaked at 4 h and dropped sharply after the peak. In contrast, addition of PA to LPS delayed the peak to 8 h and stimulated a second peak at 24 h after a transient drop at 12 h. Consistently, quantification of IL-6 in medium showed that IL-6 level in culture medium of cells treated by LPS alone plateaued at 8 h, but addition of PA to LPS led to a continuous liner increase in IL-6 in culture medium up to 48 h. Our further investigation showed that PA and LPS had a synergistic effect on the production of total ceramides and, in particular, C16 ceramide. The involvement of the synergistic effect of LPS and PA on ceramide production in IL-6 upregulation was indicated by the findings that myriocin and fumonisin B1, the inhibitors of ceramide de novo synthesis, and GW4869, an inhibitor of sphingomyelin hydrolysis, reduced IL-6 secretion by cells treated with LPS and PA significantly. Taken together, this study has demonstrated that PA enhances the stimulatory effect of LPS on IL-6 expression in cardiac MIC ECs by increasing ceramide production via both de novo synthesis and sphingomyelin hydrolysis.
Abstract 329: Myxomavirus-derived Serpin Prolongs Survival and Reduces Vasculitis in MHV68 Infected Mice by Enhancing IL-10
Authors: Chen Hao , Zheng Donghang , Liying Liu , Mee Y Bartee , Davids Jennifer , Davids Jennifer , Macaulay Colin , McFadden Grant , Thoburn Robert , Lomas David A , Virgin Herbert W , Lucas Alexandra
Published: March 2022

Background

Lethal viral infections produce widespread inflammation with vascular leaking, clotting and bleeding (DIC), and high mortality. Serine proteases in clot-forming (thrombotic) and clot-dissolving (thrombolytic) cascades are activated by a cytokine storm and also induce systemic inflammation. Normal host
ser
ine
p
roteases
in
hibitor (
serpin
) regulation is lost. Serp-1 is a potent myxomavirus anti-inflammatory protein, which inhibits factor X (fX), tPA and uPA
in vitro
. Serp-1 reduces arterial inflammation and atherogenesis in many animal models and has been successfully tested in patients with unstable plaque and stent implants.

Methods and results

Purified Serp-1 protein treatment significantly improved survival in lethal murine
Gammaherpesvirus-68
(MHV68) infection in interferon gamma receptor (IFNγR) knock-out mice (N = 72 mice; P < 0.02) when given for 10 up to 30 days after infection. Treatment with a mammalian serpin, neuroserpin, that inhibits only tPA and uPA, was ineffective (N = 30 mice; P = NS). Serp-1 reduced viral antigen, lung hemorrhage, and aortic, lung and colon inflammation in MHV68 infected mice. Neuroserpin suppressed a wide swath of immune cell responses, while Serp-1 selectively increased CD11c+ splenocytes (macrophage and dendritic cells) and reduced CD11b+ tissue macrophage. Serp-1 significantly increased the IL-10 gene expression in aorta and plasma protein, whereas neuroserpin decreased IL-10. Serp-1 mediated survival in MHV68 infected mice was lost after treatment with IL-10 receptor antibody immediately post infection (N = 12 mice; P =0.014).

Conclusions

Serp-1, a unique myxomavirus-deried serpin, improves survival after lethal mouse herpesviral infection, reduces viral load, hemorrhage and arterial inflammation. Serp-1 provides a potential new therapeutic approach for lethal viral sepsis and DIC through altered FX and IL-10.
Abstract 334: Hypertensive Crisis Combined with Acute Myocardial Ischemic Injury after Glatiramer Acetate Subcutaneous Injection: A Case Presentation and Literature Review
Authors: Paulino Robert , Shi Qi , Samavedam Sandhya , Kakde Amit , Kiel Michael , Wu Huimin , Crevecoeur Louis , Jia Jihua
Published: March 2022

Introduction

Hypertensive crisis (HC) affects more than a half million Americans each year, and leave many with irreversible injury. Despite extensive studies on HC and its complications, there remain many unrecognized risk factors and prognosticators. Physicians should perform comprehensive evaluation, including a current medication list review of patients who present with HC to effectively identify the cause and intervene accordingly. We present a case of HC with acute myocardial damage after subcutaneous injection of glatiramer acetate

Case presentation

A 47 year-old Caucasian male with history of multiple sclerosis (MS) who presented to the emergency room with complaints of headache, chest discomfort, and cough with frothy bloody secretions approximately 30 minutes after subcutaneous injection of glatiramer acetate. For the past 5 years, the patient had reported occasional hot flashes, headache, and palpitations after injection of glatiramer acetate. On examination, blood pressure was 260/160mmHg and heart rate was 120bpm. Chest X-ray showed acute pulmonary edema. EKG showed significant ST elevations in leads I and AVL and ST depressions in leads II, III, and AVF. Troponin levels were elevated during first 24 hours (0.1, 3.7, and 3.5 μg/L). Echocardiography revealed an ejection fraction of 45% with left ventricular wall hypokinesis. Blood pressure was controlled with intravenous nitroprusside and labetalol and after 48hours, repeat EKG was normal, and stress test with myoview was negative for ischemic changes.

Discussion

Hypertensive crisis is associated with significant morbidity and mortality. Myocardial damage often results from HC and causes subsequent heart failure which leads to death of sufferers. Glatiramer acetate (Copaxone) is an immunomodulator currently used to reduce symptomatic episodes in patients with relapsing-remitting MS. During the post-marketing period, there have been reports of patients with hypertension, chest pain, and others symptoms that received emergency medical care; however, HC combined with acute myocardial damage has been never reported. Whether an immunologic or non-immunologic mechanism mediates these episodes is unknown.