Atherosclerotic Plaque Components Research Articles

Sodium Danshensu Inhibits Macrophage Inflammation in Atherosclerosis via the miR-200a-3p/MEKK3/NF-κB Signaling Pathway.

Macrophages are fundamental cellular components of atherosclerotic plaques, and inhibition of macrophage inflammation can delay the development of atherosclerotic plaques. Sodium danshensu (SDSS) can inhibit inflammatory responses and thus delay atherosclerosis, but the specific mechanism remains unclear.The effect of SDSS in inhibiting atherosclerosis was confirmed by observing and detecting atherosclerotic plaque area, morphology and lipid levels in the aorta. The mechanism by which SDSS attenuated atherosclerotic plaques was elucidated by in vivo and in vitro detection of inflammation-related mRNA and protein expression. In addition, bioinformatics analysis, RT-qPCR and dual-luciferase assays were used to predict and validate the potential miRNAs of SDSS to attenuate atherosclerosis. miR-200a-2p mimic and inhibitor were then compared for their effects on the efficacy of SDSS.SDSS inhibited atherosclerotic plaque formation and suppressed the expression of MEKK3, TNF-α, and IL-1β as well as nuclear factor-κB (NF-κB) phosphorylation and nuclear translocation to attenuate inflammatory responses. Bioinformatic predictions combined with RT-qPCR results and dual-luciferase assays indicated that miR-200a-3p negatively regulated MEKK3 expression by directly targeting the 3'UTR region of MEKK3, thereby blocking MEKK3. Further studies showed that miR-200a-3p inhibitor, but not miR-200a-3p mimic, reversed the beneficial effects of SDSS on inflammation.SDSS inhibited macrophage inflammation by modulating the miR-200a-3p/MEKK3/NF-κB signaling pathway.

MAIN MORPHOLOGICAL FEATURES OF THROMBI FORMED IN CORONARY ARTERIES

Abstract. Purpose: to explore the features of the structure of intracoronary thrombi obtained during manual thromboaspiration as part of primary percutaneous coronary intervention in patients with acute ST-segment elevation myocardial infarction (STEMI). Materials and Methods. The study included 100 patients with STEMI. All of them underwent stenting preceded by manual thromboaspiration. The obtained material was fixed in formalin and stained with hematoxylin-eosin and orange-red-blue (Zerbino- Lukasiewicz method). Results. Based on the fibrin age assessment, the thrombi were old or fresh. Some thrombi showed signs of organization in the form of microchannels. Homogeneous and layered thrombi were distinguished by structure. Sometimes there were pronounced signs of neutrophil infiltration, mainly along the periphery of the thrombus. Occasionally, components of atherosclerotic plaque were found in intracoronary thrombi. Most often these were cholesterol crystals and foam cells. Conclusions. Intracoronary thrombi formed in STEMI have different ages and different structural features. This is probably due to the peculiarities of the pathogenesis of the disease.

In Vivo Classification and Characterization of Carotid Atherosclerotic Lesions with Integrated 18F-FDG PET/MRI.

The aim of this study was to exploit integrated PET/MRI to simultaneously evaluate the morphological, component, and metabolic features of advanced atherosclerotic plaques and explore their incremental value. In this observational prospective cohort study, patients with advanced plaque in the carotid artery underwent 18F-FDG PET/MRI. Plaque morphological features were measured, and plaque component features were determined via MRI according to AHA lesion-types. Maximum standardized uptake values (SUVmax) and tissue to background ratio (TBR) on PET were calculated. Area under the receiver-operating characteristic curve (AUC) and net reclassification improvement (NRI) were used to compare the incremental contribution of FDG uptake when added to AHA lesion-types for symptomatic plaque classification. A total of 280 patients with advanced plaque in the carotid artery were recruited. A total of 402 plaques were confirmed, and 87 of 402 (21.6%) were symptomatic plaques. 18F-FDG PET/MRI was performed a mean of 38 days (range 1-90) after the symptom. Increased stenosis degree (61.5% vs. 50.0%, p < 0.001) and TBR (2.96 vs. 2.32, p < 0.001) were observed in symptomatic plaques compared with asymptomatic plaques. The performance of the combined model (AHA lesion type VI + stenosis degree + TBR) for predicting symptomatic plaques was the best among all models (AUC = 0.789). The improvement of the combined model (AHA lesion type VII + stenosis degree + TBR) over AHA lesion type VII model for predicting symptomatic plaques was the highest (AUC = 0.757/0.454, combined model/AHA lesion type VII model), and the NRI was 50.7%. Integrated PET/MRI could simultaneously evaluate the morphological component and inflammation features of advanced atherosclerotic plaques and provide supplementary optimization information over AHA lesion-types for identifying vulnerable plaques in atherosclerosis subjects to achieve further stratification of stroke risk.

Targeting deubiquitinase OTUB1 protects vascular smooth muscle cells in atherosclerosis by modulating PDGFRβ.

Atherosclerosis is a chronic artery disease that causes various types of cardiovascular dysfunction. Vascular smooth muscle cells (VSMCs), the main components of atherosclerotic plaque, switch from contractile to synthetic phenotypes during atherogenesis. Ubiquitylation is crucial in regulating VSMC phenotypes in atherosclerosis, and it can be reversely regulated by deubiquitinases. However, the specific effects of deubiquitinases on atherosclerosis have not been thoroughly elucidated. In this study, RNAi screening in human aortic smooth muscle cells was performed to explore the effects of OTU family deubiquitinases, which revealed that silencing OTUB1 inhibited PDGF-BB-stimulated VSMC phenotype switch. Further in vivo studies using Apoe-/- mice revealed that knockdown of OTUB1 in VSMCs alleviated atherosclerosis plaque burden in the advanced stage and led to a stable plaque phenotype. Moreover, VSMC proliferation and migration upon PDGF-BB stimulation could be inhibited by silencing OTUB1 in vitro. Unbiased RNA-sequencing data indicated that knocking down OTUB1 influenced VSMC differentiation, adhesion, and proliferation. Mass spectrometry of ubiquitinated protein confirmed that proteins related to cell growth and migration were differentially ubiquitylated. Mechanistically, we found that OTUB1 recognized the K707 residue ubiquitylation of PDGFRβ with its catalytic triad, thereby reducing the K48-linked ubiquitylation of PDGFRβ. Inhibiting OTUB1 in VSMCs could promote PDGFRβ degradation via the ubiquitin-proteasome pathway, so it was beneficial in preventing VSMCs' phenotype switch. These findings revealed that knocking down OTUB1 ameliorated VSMCs' phenotype switch and atherosclerosis progression, indicating that OTUB1 could be a valuable translational therapeutic target in the future.

Photodynamic Therapy for Atherosclerosis.

Atherosclerosis, which currently contributes to 31% of deaths globally, is of critical cardiovascular concern. Current diagnostic tools and biomarkers are limited, emphasizing the need for early detection. Lifestyle modifications and medications form the basis of treatment, and emerging therapies such as photodynamic therapy are being developed. Photodynamic therapy involves a photosensitizer selectively targeting components of atherosclerotic plaques. When activated by specific light wavelengths, it induces localized oxidative stress aiming to stabilize plaques and reduce inflammation. The key advantage lies in its selective targeting, sparing healthy tissues. While preclinical studies are encouraging, ongoing research and clinical trials are crucial for optimizing protocols and ensuring long-term safety and efficacy. The potential combination with other therapies makes photodynamic therapy a versatile and promising avenue for addressing atherosclerosis and associated cardiovascular disease. The investigations underscore the possibility of utilizing photodynamic therapy as a valuable treatment choice for atherosclerosis. As advancements in research continue, photodynamic therapy might become more seamlessly incorporated into clinical approaches for managing atherosclerosis, providing a blend of efficacy and limited invasiveness.

Advances in Artificial Intelligence-Assisted Coronary Computed Tomographic Angiography for Atherosclerotic Plaque Characterization.

Coronary artery disease is a leading cause of death worldwide. Major adverse cardiac events are associated not only with coronary luminal stenosis but also with atherosclerotic plaque components. Coronary computed tomography angiography (CCTA) enables non-invasive evaluation of atherosclerotic plaque along the entire coronary tree. However, precise and efficient assessment of plaque features on CCTA is still a challenge for physicians in daily practice. Artificial intelligence (AI) refers to algorithms that can simulate intelligent human behavior to improve clinical work efficiency. Recently, cardiovascular imaging has seen remarkable advancements with the use of AI. AI-assisted CCTA has the potential to facilitate the clinical workflow, offer objective and repeatable quantitative results, accelerate the interpretation of reports, and guide subsequent treatment. Several AI algorithms have been developed to provide a comprehensive assessment of atherosclerotic plaques. This review serves to highlight the cutting-edge applications of AI-assisted CCTA in atherosclerosis plaque characterization, including detecting obstructive plaques, assessing plaque volumes and vulnerability, monitoring plaque progression, and providing risk assessment. Finally, this paper discusses the current problems and future directions for implementing AI in real-world clinical settings.

Multifunctional liposomes Co-encapsulating epigallocatechin-3-gallate (EGCG) and miRNA for atherosclerosis lesion elimination.

Atherosclerosis (AS) is a chronic inflammatory disease, characterized by a lipid accumulated plaque. Anti-oxidative and anti-inflammation and lipid metabolism promoting therapeutic strategies have been applied for atherosclerosis treatment. However, the therapeutic effect of a single therapeutic method is limited. It is suggested that a combination of these two strategies could help prevent lipid accumulation caused by inflammation and oxidative stress, and also promote lipid efflux from atherosclerotic plaque, to normalize arteries to the maximum extent. Hence, a strategy involving a multifunctional liposome co-encapsulating an antioxidant and anti-inflammatory drug epigallocatechin-3-gallate (EGCG) and a lipid-efflux-promoting gene miR-223 was established. The system (lip@EGCG/miR-223) could encapsulate miR-223 in core areas of the liposomes to provide a protective effect for gene drugs. Moreover, lip@EGCG/miR-223 was smaller in size (91.28 ± 2.28 nm characterized by DLS), making it easier to target AS lesions, which have smaller vascular endothelial spaces. After being efficiently internalized into the cells, lip@EGCG/miR-223 exhibited excellent antioxidant and anti-inflammatory effects in vitro by eliminating overproduced ROS and decreasing the level of inflammatory cytokines (TNF-α, IL-1β, and MCP-1), which was due to the effect of EGCG. Besides, the lipid-efflux-promoting protein ABCA1 was upregulated when treated with lip@EGCG/miR-223. Through the two therapies mentioned, lip@EGCG/miR-223 could effectively inhibit the formation of foam cells, which are a main component of atherosclerotic plaques. In AS model mice, after intravenous (i.v.) administration, lip@EGCG/miR-223 was effectively accumulated in atherosclerotic plaques, and the distribution of drugs in the heart and aorta compared to that in the kidney was significantly increased when compared with free drugs (the ratio was 6.27% for the free miR-223-treated group, which increased to 66.10% for the lip@EGCG/miR-223-treated group). By decreasing the inflammation level and lipid accumulation, the arterial vessels in AS were normalized, with less macrophages and micro-angiogenesis, when treated with lip@EGCG/miR-223. Overall, this study demonstrated that lip@EGCG/miR-223 could be developed as a potential system for atherosclerosis treatment by a combined treatment of antioxidant, anti-inflammatory, and lipid-efflux-promoting effects, which provides a novel strategy for the safe and efficient management of atherosclerosis.

Carotid atherosclerotic plaque segmentation in multi-weighted MRI using a two-stage neural network: advantages of training with high-resolution imaging and histology.

A reliable and automated method to segment and classify carotid artery atherosclerotic plaque components is needed to efficiently analyze multi-weighted magnetic resonance (MR) images to allow their integration into patient risk assessment for ischemic stroke. Certain plaque components such as lipid-rich necrotic core (LRNC) with hemorrhage suggest a greater likelihood of plaque rupture and stroke event. Assessment for presence and extent of LRNC could assist in directing treatment with impact upon patient outcomes. To address the need to accurately determine the presence and extent of plaque components on carotid plaque MRI, we proposed a two-staged deep-learning-based approach that consists of a convolutional neural network (CNN), followed by a Bayesian neural network (BNN). The rationale for the two-stage network approach is to account for the class imbalance of vessel wall and background by providing an attention mask to the BNN. A unique feature of the network training was to use ground truth defined by both high-resolution ex vivo MRI data and histopathology. More specifically, standard resolution 1.5 T in vivo MR image sets with corresponding high resolution 3.0 T ex vivo MR image sets and histopathology image sets were used to define ground-truth segmentations. Of these, data from 7 patients was used for training and from the remaining two was used for testing the proposed method. Next, to evaluate the generalizability of the method, we tested the method with an additional standard resolution 3.0 T in vivo data set of 23 patients obtained from a different scanner. Our results show that the proposed method yielded accurate segmentation of carotid atherosclerotic plaque and outperforms not only manual segmentation by trained readers, who did not have access to the ex vivo or histopathology data, but also three state-of-the-art deep-learning-based segmentation methods. Further, the proposed approach outperformed a strategy where the ground truth was generated without access to the high resolution ex vivo MRI and histopathology. The accurate performance of this method was also observed in the additional 23-patient dataset from a different scanner. In conclusion, the proposed method provides a mechanism to perform accurate segmentation of the carotid atherosclerotic plaque in multi-weighted MRI. Further, our study shows the advantages of using high-resolution imaging and histology to define ground truth for training deep-learning-based segmentation methods.

Current Toolset in Predicting Acute Coronary Thrombotic Events: The “Vulnerable Plaque” in a “Vulnerable Patient” Concept

Despite major advances in pharmacotherapy and interventional procedures, coronary artery disease (CAD) remains a principal cause of morbidity and mortality worldwide. Invasive coronary imaging along with the computation of hemodynamic forces, primarily endothelial shear stress and plaque structural stress, have enabled a comprehensive identification of atherosclerotic plaque components, providing a unique insight into the understanding of plaque vulnerability and progression, which may help guide patient treatment. However, the invasive-only approach to CAD has failed to show high predictive value. Meanwhile, it is becoming increasingly evident that along with the "vulnerable plaque", the presence of a "vulnerable patient" state is also necessary to precipitate an acute coronary thrombotic event. Non-invasive imaging techniques have also evolved, providing new opportunities for the identification of high-risk plaques, the study of atherosclerosis in asymptomatic individuals, and general population screening. Additionally, risk stratification scores, circulating biomarkers, immunology, and genetics also complete the armamentarium of a broader "vulnerable plaque and patient" concept approach. In the current review article, the invasive and non-invasive modalities used for the detection of high-risk plaques in patients with CAD are summarized and critically appraised. The challenges of the vulnerable plaque concept are also discussed, highlighting the need to shift towards a more interdisciplinary approach that can identify the "vulnerable plaque" in a "vulnerable patient".

Phosphotungstic acid (PTA) preferentially binds to collagen- rich regions of porcine carotid arteries and human atherosclerotic plaques observed using contrast enhanced micro-computed tomography (CE-µCT).

Background and aims: Atherosclerotic plaque rupture in the carotid artery can cause small emboli to travel to cerebral arteries, causing blockages and preventing blood flow leading to stroke. Contrast enhanced micro computed tomography (CEμCT) using a novel stain, phosphotungstic acid (PTA) can provide insights into the microstructure of the vessel wall and atherosclerotic plaque, and hence their likelihood to rupture. Furthermore, it has been suggested that collagen content and orientation can be related to mechanical integrity. This study aims to build on existing literature and establish a robust and reproducible staining and imaging technique to non-destructively quantify the collagen content within arteries and plaques as an alternative to routine histology. Methods: Porcine carotid arteries and human atherosclerotic plaques were stained with a concentration of 1% PTA staining solution and imaged using MicroCT to establish the in situ architecture of the tissue and measure collagen content. A histological assessment of the collagen content was also performed from picrosirius red (PSR) staining. Results: PTA stained arterial samples highlight the reproducibility of the PTA staining and MicroCT imaging technique used with a quantitative analysis showing a positive correlation between the collagen content measured from CEμCT and histology. Furthermore, collagen-rich areas can be clearly visualised in both the vessel wall and atherosclerotic plaque. 3D reconstruction was also performed showing that different layers of the vessel wall and various atherosclerotic plaque components can be differentiated using Hounsfield Unit (HU) values. Conclusion: The work presented here is unique as it offers a quantitative method of segmenting the vessel wall into its individual components and non-destructively quantifying the collagen content within these tissues, whilst also delivering a visual representation of the fibrous structure using a single contrast agent.

Intraplaque neovascularisation is associated with ischaemic events after carotid artery stenting: an observational prospective study.

Intraplaque neovascularisation (IPN) is a component of vulnerable atherosclerotic plaque, which is a biomarker of cardiovascular events. However, the identification of patients with high probability of ischaemic events after carotid artery stenting (CAS) is mainly based on vascular risk factors. Prospective studies on the development of plaques are lacking. The purpose of this study was to investigate whether IPN detected by contrast-enhanced ultrasound is related to the occurrence of ischaemic events after CAS. Sixty consecutive patients receiving CAS were prospectively enrolled in our centre. The patients were evaluated using contrast-enhanced ultrasound before CAS. According to the degree of microbubble enhancement, IPN was graded from 0 to 2. Endpoint events, including ischaemic stroke and other cardiovascular events, were recorded during follow-up. Kaplan-Meier survival curves and Cox proportional-hazards models were used to evaluate the risk factors for endpoint events. At a median follow-up of 30 months, 13 patients (28.9%) experienced endpoint events. Kaplan-Meier survival curves showed that patients with grade 2 IPN had a higher risk of future ischaemic events than those with grade 0 or 1 IPN (p < 0.05). Cox proportional-hazards models showed that grade 2 IPN [adjusted hazard ratio (HR), 4.049; 95% confidence interval (CI), 1.078-15.202] was a significant predictor of endpoint events (p < 0.05). Grade 2 IPN evaluated by contrast-enhanced ultrasound has predictive value for ischaemic events in patients after CAS and may help clinicians identify high-risk patients who need close follow-up. Neovascularisation and carotid artery stenting Introduction: Introduction: It is unclear whether intraplaque neovascularisation (IPN) can be used as an biomarker of high probability ischemic events after carotid artery stenting (CAS).Materials and methods: We enrolled 60 patients who underwent CAS, all of whom underwent CEUS before CAS. We recorded ischaemic events during follow-up. Cox proportional-hazards models were used to evaluate the risk factors for ischaemic events.Results: We found that grade 2 IPN was an independent predictor (hazard ratio, 4.049; 95% confidence interval, 1.078-15.202; p < 0.05) of ischaemic events in patients after CAS.Conclusion: This may help clinicians identify high-risk patients who need close follow-up.

Schisanhenol Attenuates OxLDL-Induced Endothelial Dysfunction via an AMPK-Dependent Mechanism.

Atherosclerotic cardiovascular diseases, commonly known as the formation of fibrofatty lesions in the artery wall, are the leading causes of death globally. Oxidized low-density lipoprotein (oxLDL) is one of the major components of atherosclerotic plaques. It is evident that dietary supplementation containing sources of antioxidants can prevent atherogenic diseases. Schisanhenol (SAL), a dibenzocyclooctene lignin, has been shown to attenuate oxLDL-induced apoptosis and the generation of reactive oxygen species (ROS) in endothelial cells. However, the underlying molecular mechanisms are still largely unknown. In this study, human umbilical vein endothelial cells (HUVECs) were pre-treated with SAL and oxLDL. Our results showed that adenosine monophosphate-activated protein kinase (AMPK) phosphorylation was enhanced in cells pre-treated with SAL in time-dependent and dose-dependent manners. Subsequently, oxLDL-induced AMPK dephosphorylation and protein kinase C (PKC) phosphorylation were significantly reversed in the presence of SAL. In addition, SAL treatment led to an inhibiting effect on the oxLDL-induced membrane assembly of NADPH oxidase subunits, and a similar effect was observed in ROS generation. This effect was further confirmed using knockdown AMPK with small interfering RNA (siRNA) and pharmaceutical reagents, such as the AMPK activator (AICAR), PKC inhibitor (Gö 6983), and ROS inhibitor (DPI). Furthermore, the oxLDL-induced intracellular calcium rise and the potential collapse of the mitochondrial membrane reduced the Bcl-2/Bax ratio, and released cytochrome c from the mitochondria, leading to the subsequent activation of caspase-3 in HUVECs, which were also markedly suppressed by SAL pretreatment. The results mentioned above may provide additional insights into the possible molecular mechanisms underlying the cardiovascular protective effects of SAL.

Macrophage-, Dendritic-, Smooth Muscle-, Endothelium-, and Stem Cells-Derived Foam Cells in Atherosclerosis.

Atherosclerosis is an inflammatory disease depending on the buildup, called plaque, of lipoproteins, cholesterol, extracellular matrix elements, and various types of immune and non-immune cells on the artery walls. Plaque development and growth lead to the narrowing of the blood vessel lumen, blocking blood flow, and eventually may lead to plaque burst and a blood clot. The prominent cellular components of atherosclerotic plaque are the foam cells, which, by trying to remove lipoprotein and cholesterol surplus, also participate in plaque development and rupture. Although the common knowledge is that the foam cells derive from macrophages, studies of the last decade clearly showed that macrophages are not the only cells able to form foam cells in atherosclerotic plaque. These findings give a new perspective on atherosclerotic plaque formation and composition and define new targets for anti-foam cell therapies for atherosclerosis prevention. This review gives a concise description of foam cells of different pedigrees and describes the main mechanisms participating in their formation and function.

Vessel wall MR imaging of aortic arch, cervical carotid and intracranial arteries in patients with embolic stroke of undetermined source: A narrative review.

Despite advancements in multi-modal imaging techniques, a substantial portion of ischemic stroke patients today remain without a diagnosed etiology after conventional workup. Based on existing diagnostic criteria, these ischemic stroke patients are subcategorized into having cryptogenic stroke (CS) or embolic stroke of undetermined source (ESUS). There is growing evidence that in these patients, non-cardiogenic embolic sources, in particular non-stenosing atherosclerotic plaque, may have significant contributory roles in their ischemic strokes. Recent advancements in vessel wall MRI (VW-MRI) have enabled imaging of vessel walls beyond the degree of luminal stenosis, and allows further characterization of atherosclerotic plaque components. Using this imaging technique, we are able to identify potential imaging biomarkers of vulnerable atherosclerotic plaques such as intraplaque hemorrhage, lipid rich necrotic core, and thin or ruptured fibrous caps. This review focuses on the existing evidence on the advantages of utilizing VW-MRI in ischemic stroke patients to identify culprit plaques in key anatomical areas, namely the cervical carotid arteries, intracranial arteries, and the aortic arch. For each anatomical area, the literature on potential imaging biomarkers of vulnerable plaques on VW-MRI as well as the VW-MRI literature in ESUS and CS patients are reviewed. Future directions on further elucidating ESUS and CS by the use of VW-MRI as well as exciting emerging techniques are reviewed.

Complex carotid artery segmentation in multi-contrast MR sequences by improved optimal surface graph cuts based on flow line learning.

Carotid atherosclerosis is one of the leading causes of cardiovascular disease with high mortality. Multi-contrast MRI can identify atherosclerotic plaque components with high sensitivity and specificity. Accurate segmentation of the diseased carotid artery from MR images is very essential to quantitatively evaluate the state of atherosclerosis. However, due to the complex morphology of atherosclerosis plaques and the lack of well-annotated data, the segmentation of lumen and wall is very challenging. Different from popular deep learning methods, in this paper, we propose an integration segmentation framework by introducing a lightweight prediction model and improved optimal surface graph cuts (OSG), which adopts a simplified flow line sampling and post-reconstructing method to reduce the cost of graph construction. Moreover, a flexibly adaptive smoothing penalty is presented for maintaining the shape of diseased carotid surface. For the experiments, we have collected an MR image dataset from patients with carotid atherosclerosis and evaluated our method by cross-validation. It can reach 89.68%/80.29% of dice coefficients and 0.2480 mm/0.3396 mm of average surface distances on the lumen/wall segmentation, respectively. The experimental results show that our method can generate precise and reliable segmentation of both lumen and wall of diseased carotid artery with a quite small training cost.

Association Between Changes in Perivascular Adipose Tissue Density and Plaque Progression

BackgroundThe association between the change in vessel inflammation, as quantified by perivascular adipose tissue (PVAT) density, and the progression of coronary atherosclerosis remains to be determined. ObjectivesThe purpose of this study was to explore the association between the change in PVAT density and the progression of total and compositional plaque volume (PV). MethodsPatients were selected from a prospective multinational registry. Patients who underwent serial coronary computed tomography angiography studies with ≥2-year intervals and were scanned with the same tube voltage at baseline and follow-up were included. Total and compositional PV and PVAT density at baseline and follow-up were quantitatively analyzed for every lesion. Multivariate linear regression models using cluster analyses were constructed. ResultsA total of 1,476 lesions were identified from 474 enrolled patients (mean age 61.2 ± 9.3 years; 65.0% men). The mean PVAT density was −74.1 ± 11.5 HU, and total PV was 48.1 ± 83.5 mm3 (19.2 ± 44.8 mm3 of calcified PV and 28.9 ± 51.0 mm3 of noncalcified PV). On multivariate analysis (adjusted for clinical risk factors, medication use, change in lipid levels, total PV at baseline, luminal HU attenuation, location of lesions, and tube voltage), the increase in PVAT density was positively associated with the progression of total PV (estimate = 0.275 [95% CI: 0.004-0.545]; P = 0.047), driven by the association with fibrous PV (estimate = 0.245 [95% CI: 0.070-0.420]; P = 0.006). Calcified PV progression was not associated with the increase in PVAT density (P > 0.050). ConclusionsIncrease in vessel inflammation represented by PVAT density is independently associated with the progression of the lipid component of coronary atherosclerotic plaques. (Progression of AtheRosclerotic PlAque DetermIned by Computed TomoGraphic Angiography Imaging [PARADIGM]; NCT02803411)

CD36 down regulation by the macrophage antioxidant 7,8-dihydroneopterin through modulation of PPAR-γ activity

CD36 is the key scavenger receptor driving the formation of cholesterol-loaded foam cells, the principal cellular component of atherosclerotic plaques. CD36 is down regulated by 7,8-dihydroneopterin, a potent superoxide and hypochlorite scavenging antioxidant generated by interferon-γ stimulated macrophages. 7,8-dihydroneopterin downregulates CD36 mRNA and protein levels so inhibiting macrophage foam cell formation in vitro. We examined the mechanism of 7,8-dihydroneopterin downregulation of CD36 by measuring CD36 and PPAR-γ levels by Western blot analysis, in the monocyte-like U937 cells with a range of PPAR-γ stimulants and inhibitors. Lipoxygenase activity was measured by monitoring linoleic acid oxidation at 234 nm for diene formation. Between 100 and 200 μM, 7,8-dihydroneopterin decreased CD36 levels by 50% within 12 h with levels dropping below 25% by 24 h. CD36 levels returned to basal levels after 24 h. Inhibition of protein synthesis by cycloheximide shows 7,8-dihydroneopterin had no effect on CD36 degradation rates. PPAR-γ levels were not altered by the addition of 7,8-dihydroneopterin. MAP Kinase, P38 and NF-κB pathways inhibitors SP600125, PD98059, SB202190 and BAY 11-7082, respectively, did not restore the CD36 levels in the presence of 7,8-dihydroneopterin. The addition of the lipophilic PPAR-γ activators rosiglitazone and azelaoyl-PAF prevented the CD36 downregulation by 7,8-dihydroneopterin. 7,8-dihydroneopterin inhibited soybean lipoxygenase and reduced U937 cell basal levels of cellular lipid oxides as measured by HPLC-TBARS analysis. The data show 7,8-dihydroneopterin down regulates CD36 expression by decreasing the level of lipid oxide stimulation of PPAR-γ promotor activity, potentially through lipoxygenase inhibition.

Impact of small dense low-density lipoprotein cholesterol on cholesterol crystals in patients with acute coronary syndrome: An optical coherence tomography study

The presence of cholesterol crystals (CCs) is recognized as a component of vulnerable atherosclerotic plaques at risk of rupture. The phagocytosis of atherogenic lipid factors by macrophages precedes and promotes the formation of vulnerable plaques, but it is not clear how these factors affect the formation of CC. This study aimed to evaluate the relationship between lipid biomarkers such as small dense low-density lipoprotein cholesterol (sd-LDL-c) and CC detected by optical coherence tomography (OCT) in patients with acute coronary syndrome (ACS). Serum samples were collected immediately before coronary angiography in consecutive 174 patients with ACS who did not take statins and underwent OCT imaging of the culprit lesion. The sd-LDL-c levels were measured using a direct homogenous assay. CC was defined as a thin linear structure with high reflectivity and low signal attenuation on the OCT images. CC was identified in 85 patients (48.9%). The prevalence of CC was significantly higher in lesions with ruptured plaques and greater macrophage grade. The sd-LDL-c levels were significantly higher in the patients with CC (41.6 vs. 31.2 mg/dL, p=0.01) although there were no significant differences in the levels of LDL-c and apolipoprotein B. The CC group also had higher levels of apolipoprotein C3 and HbA1c levels. In multiple logistic regression analysis, sd-LDL-c was an independent risk factor of CC (odds ratio, 1.19 per 10 mg/dL; p=0.03). sd-LDL may play an important role in the presence of CC in patients with ACS.

Abstract 314: The Alteration In Cell Mechanics In Atherosclerosis

Atherosclerosis remains a major cause of cardiovascular disease. It is well known that the cholesterol accumulated in the macrophage-derived foam cells is the major component of atherosclerotic plaque. However, the growing evidence suggests that about 40% of the total foam cells in the atherosclerotic plaque were vascular smooth muscle cells (VSMCs)-derived. VSMCs are the major cellular components of arterial wall and undergo phenotypic switching from a functional contractile phenotype to a synthetic proliferative phenotype during the development of atherosclerosis. In addition, the surrounding environment of VSMCs within vascular wall changes with alterations in extracellular matrix (ECM) stiffness and composition. The main goal of this study is to test hypothesis that VSMC mechanics undergoes significant changes in response to these surrounding microenvironment alteration in the progression of atherosclerosis. We employed an innovative approach integrating a series of novel experimental approaches and data-driven mathematical models to monitor the real time mechanics of VSMCs isolated from western diet fed apolipoprotein-E knockout (ApoE -/- ) and wild type (WT) mice. The results demonstrated significant differences in the actin cytoskeletal organization and cell mechanics between ApoE -/- VSMCs and WT cells, which may trigger the VSMC migration and contribute to the formation of the arterial plaque. These interesting finding will lead to a novel therapeutic strategy for the pharmaceutical treatment of atherosclerosis by interfering the alteration in VSMC mechanics.

Enhanced expression of lectin‐like oxidized LDL receptor‐1 is implicated in the sodium arsenite‐induced increase in foam cells from murine macrophages

Arsenic is a naturally occurring toxic element that is present in the air, food, soil, and water of many countries, including the U.S. The U.S. Geological Survey reported that about 44 million people in the U.S. use private wells for water and estimated that over 2 million of those people drink from wells with high concentrations (&gt;10 ug/L) of arsenic. Epidemiological studies have shown that chronic arsenic exposure is a significant risk factor for cardiovascular diseases, including atherosclerosis. However, the cellular and molecular mechanisms connecting arsenic exposure to atherosclerosis are not known. It has been established that Macrophage‐derived, lipid‐loaded, foam cells are a key component of atherosclerotic plaques and are essential for their formation. Furthermore scavenger receptors, such as lectin‐like oxLDL receptor 1 (LOX‐1), CD36, and scavenger receptor type A (SR‐A), regulate the lipid uptake of macrophages and are likely key to the transformation of these cells to foam cells. Our previous study showed that in mouse aortic endothelial cells, arsenic exposure stimulated the uptake of oxidized low‐density lipoprotein (oxLDL) by upregulating the expression of LOX‐1. To see if LOX‐1 might play a key role in foam cell formation, in this study, we used Oil‐red‐O assay to show that sodium arsenite (SA) exposure dose‐dependently enhanced the uptake of oxLDL in murine RAW 264.7 macrophages with a commensurate increase in foam cell count. In addition, while we showed that SA treatment caused a significant increase in both LOX‐1 mRNA and protein levels, only slight or no significant increases were observed in CD36 or SR‐A mRNA expression. Our results indicate that in arsenic induced atherosclerosis, LOX‐1 may play a critical and perhaps unique role among scavenger receptors in the production of foam cells. Further studies, including in vivo and in vitro, are warranted to verify and clarify the role of Lox‐1 in a disease model and to identify other cells and components of the disease pathway.