Plaque angiogenesis and intraplaque hemorrhage in atherosclerosis

Haematometabolism rewiring in atherosclerotic cardiovascular disease

Atherosclerotic cardiovascular diseases are the most frequent cause of death worldwide. The clinical complications of atherosclerosis are closely linked to the haematopoietic and immune systems, which maintain homeostatic functions and vital processes in the body. The nodes linking metabolism and inflammation are receiving increasing attention because they are inextricably linked to inflammatory manifestations of non-communicable diseases, including atherosclerosis. Although metabolism and inflammation are essential to survival and involve all tissues, we still know little about how these processes influence each other. In an effort to understand these mechanisms, in this Review we explore whether and how potent cardiovascular risk factors and metabolic modifiers of atherosclerosis influence the molecular and cellular machinery of 'haematometabolism' (metabolic-dependent haematopoietic stem cell skewing) and 'efferotabolism' (metabolic-dependent efferocyte reprogramming). These changes might ultimately propagate a quantitative and qualitative drift of the macrophage supply chain and affect the clinical manifestations of atherosclerosis. Refining our understanding of the different metabolic requirements of these processes could open the possibility of developing therapeutics targeting haematometabolism that, in conjunction with improved dietary habits, help rebalance and promote efficient haematopoiesis and efferocytosis and decrease the risk of atherosclerosis complications.

Cancer-associated fibroblasts (CAFs) and plaque-associated fibroblasts (PAFs): Unraveling the cellular crossroads of atherosclerosis and cancer

Atherosclerosis is a complex process involving various cells and molecules within the atherosclerotic plaque. Recent evidence suggests that plaque-associated fibroblasts (PAFs), also known as atherosclerosis-associated fibroblasts (AAFs), might play a significant role in the development and progression of the disease. The microenvironment of the atherosclerotic plaque, resembling the tumor microenvironment (TME), includes various cellular populations like plaque-associated macrophages (PAMs), plaque-associated neutrophils (PANs), vascular smooth muscle cells (VSMCs), myeloid-derived suppressor cells (MDSCs), and PAFs. Similar to cancer-associated fibroblasts (CAFs) in tumors, PAFs exhibits a wide range of characteristics and functions. Their interactions with endothelial cells, smooth muscle cells, and other stromal cells, including adventitial fibroblast precursors, significantly influence atherosclerosis progression. Moreover, the ability of PAFs to express various markers such as alpha-SMA, Desmin, VEGF, and GFAP, highlights their diverse origins from different precursor cells, including vascular smooth muscle cells, endothelial cells, glial cells of the enteric nervous system, adventitial fibroblast precursors, as well as resident and circulating fibrocytes. This article explores the molecular interactions between PAFs, cells associated with atherosclerosis, and other stromal cells. It further examines the role of PAFs in the development and progression of atherosclerosis, and compares their features with those of CAFs. The research suggests that studying tumor-associated fibroblasts can help understand fibroblast subpopulations in atherosclerotic plaque. Identifying specific subpopulations could provide new insight into atherosclerosis complexity and lead to the development of innovative drugs for medical intervention.

Epitranscriptomics in atherosclerosis: Unraveling RNA modifications, editing and splicing and their implications in vascular disease

Atherosclerosis remains a leading cause of morbidity and mortality worldwide, driven by complex molecular mechanisms involving gene regulation and post-transcriptional processes. Emerging evidence highlights the critical role of epitranscriptomics, the study of chemical modifications occurring on RNA molecules, in atherosclerosis development. Epitranscriptomics provides a new layer of regulation in vascular health, influencing cellular functions in endothelial cells, smooth muscle cells, and macrophages, thereby shedding light on the pathogenesis of atherosclerosis and presenting new opportunities for novel therapeutic targets. This review provides a comprehensive overview of the epitranscriptomic landscape, focusing on key RNA modifications such as N6-methyladenosine (m6A), 5-methylcytosine (m5C), pseudouridine (Ψ), RNA editing mechanisms including A-to-I and C-to-U editing and RNA isoforms. The functional implications of these modifications in RNA stability, alternative splicing, and microRNA biology are discussed, with a focus on their roles in inflammatory signaling, lipid metabolism, and vascular cell adaptation within atherosclerotic plaques. We also highlight how these modifications influence the generation of RNA isoforms, potentially altering cellular phenotypes and contributing to disease progression. Despite the promise of epitranscriptomics, significant challenges remain, including the technical limitations in detecting RNA modifications in complex tissues and the need for deeper mechanistic insights into their causal roles in atherosclerotic pathogenesis. Integrating epitranscriptomics with other omics approaches, such as genomics, proteomics, and metabolomics, holds the potential to provide a more holistic understanding of the disease.

The role of Epsins in atherosclerosis: From molecular mechanisms to therapeutic applications

Atherosclerosis is a multifaceted disease characterised by chronic inflammation and vascular remodelling, leading to plaque formation and cardiovascular complications. Recent evidence highlights the critical role of epsins, a family of endocytic proteins, in the pathogenesis of atherosclerosis. This manuscript explores the multifarious functions of epsins in atherosclerosis, focusing on their involvement in angiogenesis, lymphangiogenesis, and the modulation of key signalling pathways. We discuss how epsins facilitate EndoMT through their interaction with the TGFβ signalling pathway, which contributes to vascular smooth muscle cell-like phenotypes and plaque instability. Additionally, we examine the therapeutic potential of targeting epsins, elucidating their interactions with crucial partners such as LDLR, LRP-1, and TLR 2/4, among others, in mediating lipid metabolism and inflammation. Furthermore, we highlight the promising prospects of epsin-targeting peptides and small interfering RNAs as therapeutic agents for atherosclerosis treatment. Despite these advancements, the research faces limitations, including a reliance on specific mouse models and a need for comprehensive studies on the long-term effects of epsin modulation. Therefore, future investigations should focus on elucidating the detailed mechanisms of epsin function and their implications in cardiovascular health, fostering collaborations to translate basic research into innovative therapeutic strategies. This work underscores the necessity for further exploration of epsins to unlock their full therapeutic potential in combating atherosclerosis and related cardiovascular diseases.

Zedoarondiol Inhibits Neovascularization in Atherosclerotic Plaques of ApoE-/- Mice by Reducing Platelet Exosomes-Derived MiR-let-7a

OBJECTIVE

To investigate the effect of zedoarondiol on neovascularization of atherosclerotic (AS) plaque by exosomes experiment.

METHODS

ApoE-/- mice were fed with high-fat diet to establish AS model and treated with high- and low-dose (10, 5 mg/kg daily) of zedoarondiol, respectively. After 14 weeks, the expressions of anti-angiogenic protein thrombospondin 1 (THBS-1) and its receptor CD36 in plaques, as well as platelet activation rate and exosome-derived miR-let-7a were detected. Then, zedoarondiol was used to intervene in platelets in vitro, and miR-let-7a was detected in platelet-derived exosomes (Pexo). Finally, human umbilical vein endothelial cells (HUVECs) were transfected with miR-let-7a mimics and treated with Pexo to observe the effect of miR-let-7a in Pexo on tube formation.

RESULTS

Animal experiments showed that after treating with zedoarondiol, the neovascularization density in plaques of AS mice was significantly reduced, THBS-1 and CD36 increased, the platelet activation rate was markedly reduced, and the miR-let-7a level in Pexo was reduced (P<0.01). In vitro experiments, the platelet activation rate and miR-let-7a levels in Pexo were significantly reduced after zedoarondiol's intervention. Cell experiments showed that after Pexo's intervention, the tube length increased, and the transfection of miR-let-7a minics further increased the tube length of cells, while reducing the expressions of THBS-1 and CD36.

CONCLUSION

Zedoarondiol has the effect of inhibiting neovascularization within plaque in AS mice, and its mechanism may be potentially related to inhibiting platelet activation and reducing the Pexo-derived miRNA-let-7a level.

Caesalpinia sappan L. ethyl acetate extract regulated angiogenesis in atherosclerosis by modulating the miR-126/VEGF signalling pathway

Aims of the study

To investigate the regulatory mechanism of Caesalpinia sappan L. ethyl acetate extract (CSEAE) on angiogenesis in atherosclerosis (AS) based on the miR-126/VEGF signalling pathway.

Materials and methods

Our study first screened for differentially expressed microRNAs (miRNAs) associated with AS using the Gene Expression Omnibus (GEO) public database at the National Center for Biotechnology Information (NCBI) and R language software. Subsequently, our study verified the target-regulatory relationship between miR-126 and vascular endothelial growth factor (VEGF) in human umbilical vein endothelial cells (HUVECs) by using the "TargetScan" website and dual-luciferase reporter assay. In cellular experiments, Our study used cell proliferation assays and flow cytometry to assess the effects of CSEAE-Mediated serum on the proliferation and apoptosis of HUVECs. In animal experiments, our study used HE staining, Oil Red O staining and immunohistochemistry (IHC) staining to detect plaque area/lumen area (%), lipid area/plaque area (%) and microvessel density (MVD) in mouse aortas. In addition, our study performed RT‒PCR, ELISA and Western blot assays in ex vivo and in vivo experiments.

Results

A total of 39 differentially expressed miRNAs of AS were identified, among which the miR-126 expression level was significantly downregulated. Dual luciferase reporter gene assay results showed that miR-126 and VEGF have a targeting relationship, and the miR-126 mimic could inhibit the luciferase activity of the wild-type VEGF reporter gene vector (p value < 0.01). In cellular experiments, cell proliferation assays and flow cytometry results showed that CSEAE-Mediated serum significantly increased the proliferative activity after 24-72 h of treatment (p-value <0.01) and decreased the apoptotic level of HUVECs (p value < 0.01), and RT‒PCR results showed that CSEAE-Mediated serum significantly upregulated the expression of miR-126 (p value < 0.01) and downregulated the expression of VEGF mRNA in HUVECs (p value < 0.01). In vivo experiments, HE staining and IHC staining showed that CSEAE significantly reduced the MVD in the aorta and plaques of mice (p value < 0.01) and significantly reduced the aortic plaque area/lumen area (%) (p value < 0.01). Moreover, RT‒PCR assay and Western blot analysis results showed that CSEAE significantly upregulated the expression of miR-126 (p value < 0.01), downregulated the expression of VEGF mRNA (p value < 0.01), and decreased the protein expression levels of VEGF (p value < 0.01), phosphatidyl-inositol-3-kinase (PI3K) (p value < 0.01), and Ser/Thr-protein kinase (AKT1) (p value < 0.01) in mouse aortas, while ELISA showed that CSEAE significantly reduced the serum levels of vascular endothelial growth factor receptor (VEGFR2) (p value < 0.01) and hypoxia-inducible factor-1 (HIF-1) (p value < 0.01) in mice.

Conclusion

This study emphasises CSEAE as a natural medicinal extract for the treatment of AS that can improve the migratory viability and reduce the apoptosis of HUVECs to maintain the health of the arterial endothelial microenvironment, while CSEAE also inhibits angiogenesis and delays plaque formation in ApoE-/- mice, suggesting that the therapeutic effect of CSEAE for AS may be related to its inhibition of neovascularisation and that its molecular mechanism may be related to the miR-126/VEGF signalling pathway.

Atherosclerotic plaque instability in symptomatic non-significant carotid stenoses

Objective

Carotid endarterectomy for symptomatic carotid stenosis is recommended for patients with >70% stenosis, but not in those with <50%. Because non-significant, low-degree stenoses may still cause strokes, refined risk stratification is necessary, which could be improved by assessing biological features of plaque instability. To challenge risk-stratification based on luminal narrowing, we compared biological features of carotid plaques from symptomatic patients with low-degree (<50%) vs high-degree (>70%) stenosis and explored potential mechanisms behind plaque instability in low-degree stenoses.

Methods

Endarterectomy specimens were taken from symptomatic patients with high-degree (n = 204) and low-degree (n = 34) stenosis, all part of the Biobank of Karolinska Endarterectomies. Patient demographics, image-derived plaque morphology, and gene expression analyses of extracted lesions were used for comparisons. Plaque biology was assessed by transcriptomics using dimensionality reduction, differential gene expression, and gene-set enrichment analyses. Immunohistochemistry was used to study proteins corresponding to upregulated genes.

Results

The demographics of the two groups were statistically similar. Calcification, lipid-rich necrotic core, intraplaque hemorrhage, plaque burden, and fibrous cap thickness were similar in both groups, whereas the sum of lipid-rich necrotic core and intraplaque hemorrhage was higher (P = .033) in the high-degree stenosis group. Dimensionality reduction analysis indicated poor clustering separation of plaque gene expression in low-compared with high-degree stenosis lesions, whereas differential gene expression showed upregulation of hypoxia-inducible factor 3A (log2 fold change, 0.7212; P = .0003), and gene-set enrichment analyses identified pathways related to tissue hypoxia and angiogenesis in low-degree stenoses. Hypoxia-inducible factor 3-alpha protein was associated with smooth muscle cells in neo-vascularized plaque regions.

Conclusions

Plaques from symptomatic patients with non-significant low-degree carotid stenoses showed morphologic and biological features of atherosclerotic plaque instability that were comparable to plaques from patients with high-degree stenoses, emphasizing the need for improved stroke risk stratification for intervention in all patients with symptomatic carotid stenosis irrespective of luminal narrowing. An increased expression of hypoxia-inducible factor 3A in low-degree stenotic lesions suggested mechanisms of plaque instability associated with tissue hypoxia and plaque angiogenesis, but the exact role of hypoxia-inducible factor 3A in this process remains to be determined.

Clinical relevance

Carotid plaques from symptomatic patients with <50% stenosis show morphologic and biological features of plaque instability, comparable to high-degree stenosis, which emphasizes the need for improved stroke risk stratification beyond stenosis severity.

Atheroma transcriptomics identifies ARNTL as a smooth muscle cell regulator and with clinical and genetic data improves risk stratification

BACKGROUND AND AIMS

The role of vascular smooth muscle cells (SMCs) in atherosclerosis has evolved to indicate causal genetic links with the disease. Single cell RNA sequencing (scRNAseq) studies have identified multiple cell populations of mesenchymal origin within atherosclerotic lesions, including various SMC sub-phenotypes, but it is unknown how they relate to patient clinical parameters and genetics. Here, mesenchymal cell populations in atherosclerotic plaques were correlated with major coronary artery disease (CAD) genetic variants and functional analyses performed to identify SMC markers involved in the disease.

METHODS

Bioinformatic deconvolution was done on bulk microarrays from carotid plaques in the Biobank of Karolinska Endarterectomies (BiKE, n = 125) using public plaque scRNAseq data and associated with patient clinical data and follow-up information. BiKE patients were clustered based on the deconvoluted cell fractions. Quantitative trait loci (QTLs) analyses were performed to predict the effect of CAD associated genetic variants on mesenchymal cell fractions (cfQTLs) and gene expression (eQTLs) in plaques.

RESULTS

Lesions from symptomatic patients had higher fractions of Type 1 macrophages and pericytes, but lower fractions of classical and modulated SMCs compared with asymptomatic ones, particularly females. Presence of diabetes or statin treatment did not affect the cell fraction distribution. Clustering based on plaque cell fractions, revealed three patient groups, with relative differences in their stability profiles and associations to stroke, even during long-term follow-up. Several single nucleotide polymorphisms associated with plaque mesenchymal cell fractions, upstream of the circadian rhythm gene ARNTL were identified. In vitro silencing of ARNTL in human carotid SMCs increased the expression of contractile markers and attenuated cell proliferation.

CONCLUSIONS

This study shows the potential of combining scRNAseq data with vertically integrated clinical, genetic, and transcriptomic data from a large biobank of human plaques, for refinement of patient vulnerability and risk prediction stratification. The study revealed novel CAD-associated variants that may be functionally linked to SMCs in atherosclerotic plaques. Specifically, variants in the ARNTL gene may influence SMC ratios and function, and its role as a regulator of SMC proliferation should be further investigated.

Promising Adventitia in Atherosclerosis

The adventitia, the artery's most intricate layer, has received little attention. During atherosclerosis, adventitia components undergo significant changes, such as angiogenesis, lymphangiogenesis, Artery Tertiary Lymphoid Organ (ATLO) formation, axon density increase, fibroblast activation, and stem cell differentiation. The reasons behind these changes and their contribution to atherosclerosis are beginning to be understood. In this review, we summarize the adventitia components and their role in normal arteries and then discuss the changes, pathogenesis, and potential clinical application of the adventitia in atherosclerosis.

Advanced Imaging Techniques for Atherosclerosis and Cardiovascular Calcification in Animal Models

The detection and assessment of atherosclerosis and cardiovascular calcification can inform risk stratification and therapies to reduce cardiovascular morbidity and mortality. In this review, we provide an overview of current and emerging imaging techniques for assessing atherosclerosis and cardiovascular calcification in animal models. Traditional imaging modalities, such as computed tomography (CT) and magnetic resonance imaging (MRI), offer non-invasive approaches of visualizing atherosclerotic calcification in vivo; integration of these techniques with positron emission tomography (PET) imaging adds molecular imaging capabilities, such as detection of metabolically active microcalcifications with 18F-sodium fluoride. Photoacoustic imaging provides high contrast that enables in vivo evaluation of plaque composition, yet this method is limited by optical penetration depth. Light-sheet fluorescence microscopy provides high-resolution, three-dimensional imaging of cardiovascular structures and has been used for ex vivo assessment of atherosclerotic calcification, but its limited tissue penetration and requisite complex sample preparation preclude its use in vivo to evaluate cardiac tissue. Overall, with these evolving imaging tools, our understanding of cardiovascular calcification development in animal models is improving, and the combination of traditional imaging techniques with emerging molecular imaging modalities will enhance our ability to investigate therapeutic strategies for atherosclerotic calcification.

Syndecan-1 as a predictor of vulnerable atherosclerotic plaques

Aims

Cardiovascular disease remains a major global health concern, with atherosclerosis (AS) being a significant contributor. Vulnerable plaques play a critical role in acute cardiovascular events. Syndecan-1 (SDC-1), a vital membrane proteoglycan in the vascular endothelial glycocalyx, is believed to be associated with plaque progression. However, its precise relationship with severity and vulnerability of atherosclerotic plaque remains unclear. This study aimed to investigate SDC-1 expression and its potential correlation with plaque vulnerability in ApoE-/- atherosclerosis mouse model.

Methods and results

Eight-week-old mice were induced into the AS model using a high-fat diet (HFD) and/or partial ligation of the left common carotid artery (PLCA), with a chow diet (CD) control group. After 16 weeks, plaques in the aortic root showed the following order: HFD + PLCA group > HFD group > CD + PLCA group > CD group. Immunohistochemistry revealed heightened accumulation of lipid/foam cells and CD68-labeled macrophages in the plaques, elevated vascular endothelial growth factor (VEGF), and matrix Metalloproteinase-9 (MMP-9) in the HFD + PLCA group's plaques, along with reduced collagen and α-SMA-labeled smooth muscle cells, resulting in the highest vulnerability index value. Immunohistofluorescence analysis of frozen plaque sections showed significantly higher SDC-1 expression in the AS mice group compared to the CD group, both positively correlated with plaque vulnerability. Serum analysis demonstrated elevated levels of SDC1, sphingosine 1-phosphate (S1P), and VEGF-A in the AS mice, all positively correlated with plaque vulnerability. Multivariate analysis identified SDC1 as an independent predictor of plaque vulnerability.

Conclusion

This study enhances our understanding of plaque vulnerability mechanisms and presents SDC1 as a potential biomarker for atherosclerosis. These findings underscore the importance of addressing modifiable risk factors, such as diet and hemodynamics and suggest the utility of serum SDC1 as a valuable clinical marker. Ultimately, these insights may lead to more effective strategies in combating cardiovascular diseases and improving patient outcomes.

Multiomics unveils extracellular vesicle-driven mechanisms of endothelial communication in human carotid atherosclerosis

Background: Carotid atherosclerosis is orchestrated by cell-cell communication that drives progression along a clinical continuum (asymptomatic to symptomatic). Extracellular vesicles (EVs) are cell-derived nanoparticles representing a new paradigm in cellular communication. Little is known about their biological cargo, cellular origin/destination, and functional roles in human atherosclerotic plaque. Methods: EVs were enriched via size exclusion chromatography from human carotid endarterectomy samples dissected into paired plaque and marginal zones (symptomatic n=16, asymptomatic n=13). EV cargos were assessed via whole transcriptome miRNA sequencing and mass spectrometry-based proteomics. EV multi-omics were integrated with bulk and single cell RNA-sequencing (scRNA-seq) datasets to predict EV cellular origin and ligand-receptor interactions, and multi-modal biological network integration of EV-cargo was completed. EV functional impact was assessed with endothelial angiogenesis assays. Results: Carotid plaques contained more EVs than adjacent marginal zones, with differential enrichment for EV-miRNAs and EV-proteins in key atherogenic pathways. EV cellular origin analysis suggested that tissue EV signatures originated from endothelial cells (EC), smooth muscle cells (SMC), and immune cells. Integrated tissue vesiculomics and scRNA-seq indicated complex EV-vascular cell communication that changed with disease progression and plaque vulnerability (i.e., symptomatic disease). Plaques from symptomatic patients, but not asymptomatic patients, were characterized by increased involvement of endothelial pathways and more complex ligand-receptor interactions, relative to their marginal zones. Plaque-EVs were predicted to mediate communication with ECs. Pathway enrichment analysis delineated an endothelial signature with roles in angiogenesis and neovascularization - well-known indices of plaque instability. This was validated functionally, wherein human carotid symptomatic plaque EVs induced sprouting angiogenesis in comparison to their matched marginal zones. Conclusion: Our findings indicate that EVs may drive dynamic changes in plaques through EV- vascular cell communication and effector functions that typify vulnerability to rupture, precipitating symptomatic disease. The discovery of endothelial-directed angiogenic processes mediated by EVs creates new therapeutic avenues for atherosclerosis.

Assessment of Carotid Plaque Enhancement on Contrast-Enhanced Ultrasound as a Predictor for Severe Coronary Artery Disease

Background and Aim  Contrast-enhanced ultrasound (CEUS) can reliably identify vulnerable plaques. As atherosclerosis is a systemic disease, we evaluated whether contrast enhancement of carotid plaque (CECP) can predict severe coronary artery disease (CAD) by comparing CECP in patients who have had acute coronary syndromes (ACS) recently with asymptomatic individuals. Settings and Design  This case-control study was done at a tertiary care center during 2022. Materials and Methods  Fourteen participants were recruited in each group, after screening in-patients for carotid plaques and inclusion and exclusion criteria. Those who had history of ACS were enrolled as cases, while those who did not were enrolled as controls. All these patients underwent grayscale, Doppler, and CEUS examination for characterization of the carotid plaque. For cases, findings on CEUS were also compared with the severity of CAD on catheter coronary angiography. Statistical Analysis  Diagnostic parameters including sensitivity, specificity, and diagnostic accuracy were calculated and proportions were compared by using Fisher's exact test. Results  Eight out of 28 patients showed CECP. CECP and CAD were positively associated with p -Value of 0.033. Eighty-three percent patients with triple vessel disease and 50% patients with double vessel disease on coronary angiography showed CECP. Sensitivity and specificity of CECP for prediction of CAD were 50 and 92.9%, respectively. Conclusion  CECP on CEUS can predict CAD and is a more reliable indicator of severe CAD than plaque characteristics on grayscale and Doppler imaging; making it useful for screening of patients at risk of having CAD.

Association of angiogenesis-associated genes with atherosclerotic plaque progression, intraplaque hemorrhage, and immune infiltration

Mounting evidence suggests that intraplaque angiogenesis is associated with the progression of atherosclerotic plaques and the development of intraplaque hemorrhage. The specificity of intraplaque immune cell infiltration may be associated with abnormalities in the structure and function of the nascent capillaries. Here, we analyzed expression levels of angiogenesis-associated genes in early and advanced carotid atheromatous plaque tissues as well as in stable and intraplaque hemorrhage plaques. Expression profiles of advanced arterial plaques based on angiogenesis-associated genes were classified into subtypes by performing a consensus clustering analysis. The correlation between the immune microenvironment of plaques and expression of angiogenesis-associated genes was also explored using the single sample gene set enrichment analysis method and the CIBERSORT algorithm. We identified hub angiogenesis-associated genes showing similar expression patterns throughout plaque adverse progression, and constructed a prediction model using the random forest algorithm. Receiver operating curves were constructed to evaluate efficacy in identification of intraplaque hemorrhage in a plaque. Our results suggest that heterogeneity of angiogenesis-related genes may promote the malignant development of plaques and cause plaque rupture. In conclusion, we propose a model based on expression of angiogenesis-related genes to predict the risk of plaque rupture.

The Intriguing World of Vascular Remodeling, Angiogenesis, and Arteriogenesis

Vascular remodeling is a very general feature related to angiogenesis and arteriogenesis, which are involved in neovascularization processes [...].

Follicle-stimulating hormone receptor expression in advanced atherosclerotic plaques

Experimental evidence indicates that follicle-stimulating hormone (FSH), an essential hormone for reproduction, can act directly on endothelial cells inducing atherosclerosis activation and development. However, it remains unknown whether the FSH-receptor (FSHR) is expressed in human atherosclerosis plaques. To demonstrate the FSHR presence, we used immunohistochemical and immunoelectron microscopy involving a specific monoclonal antibody FSHR1A02 that recognizes an epitope present in the FSHR-ectodomain. In all 55 patients with atherosclerotic plaques located in carotid, coronary, femoral arteries, and iliac aneurysm, FSHR was selectively expressed in arterial endothelium covering atherosclerotic plaques and endothelia lining intraplaque neovessels. Lymphatic neovessels were negative for FSHR. M1-macrophages, foam cells, and giant multinucleated cells were also FSHR-positive. FSHR was not detected in normal internal thoracic artery. Immunoelectron microscopy performed in ApoEKO/hFSHRKI mice with atherosclerotic plaques, after injection in vivo with mouse anti-hFSHR monoclonal antibody FSHR1A02 coupled to colloidal gold, showed FSHR presence on the luminal surface of arterial endothelial cells covering atherosclerotic plaques. Therefore, FSHR can bind, internalize, and deliver into the plaque circulating ligands to FSHR-positive cells. In conclusion, we report FSHR expression in endothelial cells, M1-macrophages, M1-derived foam cells, giant multinucleated macrophages, and osteoclasts associated with human atherosclerotic plaques.

Molecular Pathways of Vulnerable Carotid Plaques at Risk of Ischemic Stroke: A Narrative Review

The concept of vulnerable carotid plaques is pivotal in understanding the pathophysiology of ischemic stroke secondary to large-artery atherosclerosis. In macroscopic evaluation, vulnerable plaques are characterized by one or more of the following features: microcalcification; neovascularization; lipid-rich necrotic cores (LRNCs); intraplaque hemorrhage (IPH); thin fibrous caps; plaque surface ulceration; huge dimensions, suggesting stenosis; and plaque rupture. Recognizing these macroscopic characteristics is crucial for estimating the risk of cerebrovascular events, also in the case of non-significant (less than 50%) stenosis. Inflammatory biomarkers, such as cytokines and adhesion molecules, lipid-related markers like oxidized low-density lipoprotein (LDL), and proteolytic enzymes capable of degrading extracellular matrix components are among the key molecules that are scrutinized for their associative roles in plaque instability. Through their quantification and evaluation, these biomarkers reveal intricate molecular cross-talk governing plaque inflammation, rupture potential, and thrombogenicity. The current evidence demonstrates that plaque vulnerability phenotypes are multiple and heterogeneous and are associated with many highly complex molecular pathways that determine the activation of an immune-mediated cascade that culminates in thromboinflammation. This narrative review provides a comprehensive analysis of the current knowledge on molecular biomarkers expressed by symptomatic carotid plaques. It explores the association of these biomarkers with the structural and compositional attributes that characterize vulnerable plaques.

One Endothelium-Targeted Combined Nucleic Acid Delivery System for Myocardial Infarction Therapy

Acute myocardial infarction (MI) and ischemic heart disease are the leading causes of heart failure and mortality. Currently, research on MI treatment is focused on angiogenic and anti-inflammatory therapies. Although endothelial cells (ECs) are critical for triggering inflammation and angiogenesis, no approach has targeted them for the treatment of MI. In this study, we proposed a nonviral combined nucleic acid delivery system consisting of an EC-specific polycation (CRPPR-grafted ethanolamine-modified poly(glycidyl methacrylate), CPC) that can efficiently codeliver siR-ICAM1 and pCXCL12 for the treatment of MI. Animals treated with the combination therapy exhibited better cardiac function than those treated with each nucleic acid alone. In particular, the combination therapy of CPC/siR-ICAM1 and CPC/pCXCL12 significantly improved cardiac systolic function, anti-inflammatory responses, and angiogenesis compared to the control group. In conclusion, CPC-based combined gene delivery systems show impressive performance in the treatment of MI and provide a programmed strategy for the development of codelivery systems for various EC-related diseases.

Myeloid PHD2 Conditional Knockout Improves Intraplaque Angiogenesis and Vascular Remodeling in a Murine Model of Venous Bypass Grafting

BACKGROUND

Intraplaque angiogenesis occurs in response to atherosclerotic plaque hypoxia, which is driven mainly by highly metabolically active macrophages. Improving plaque oxygenation by increasing macrophage hypoxic signaling, thus stimulating intraplaque angiogenesis, could restore cellular function and neovessel maturation, and decrease plaque formation. Prolyl hydroxylases (PHDs) regulate cellular responses to hypoxia. We therefore aimed to elucidate the role of myeloid PHD2, the dominant PHD isoform, on intraplaque angiogenesis in a murine model for venous bypass grafting.

METHODS AND RESULTS

Myeloid PHD2 conditional knockout (PHD2cko) and PHD2 wild type mice on an Ldlr-/- background underwent vein graft surgery (n=11-15/group) by interpositioning donor caval veins into the carotid artery of genotype-matched mice. At postoperative day 28, vein grafts were harvested for morphometric and compositional analysis, and blood was collected for flow cytometry. Myeloid PHD2cko induced and improved intraplaque angiogenesis by improving neovessel maturation, which reduced intraplaque hemorrhage. Intima/media ratio was decreased in myeloid PHD2cko vein grafts. In addition, PHD2 deficiency prevented dissection of vein grafts and resulted in an increase in vessel wall collagen content. Moreover, the macrophage proinflammatory phenotype in the vein graft wall was attenuated in myeloid PHD2cko mice. In vitro cultured PHD2cko bone marrow-derived macrophages exhibited an increased proangiogenic phenotype compared with control.

CONCLUSIONS

Myeloid PHD2cko reduces vein graft disease and ameliorates vein graft lesion stability by improving intraplaque angiogenesis.

Chronic Administration of Methamphetamine Aggravates Atherosclerotic Vulnerable Plaques in Apolipoprotein E Knockout Mice Fed with a High-cholesterol Diet

BACKGROUND

It has been observed previously that chronic methamphetamine (METH) administration could upregulate neuropeptide Y (NPY) expression and promote atherosclerotic formation in apolipoprotein E knockout (ApoE-/-) mice fed with a normal cholesterol or high diet and NPY might be involved in the pathogenesis of METHinduced atherogenic effects through NPY Y1 receptor pathway. Vulnerable coronary atherosclerotic plaque (VP) is a critical pathological finding responsible for the acute coronary syndrome (ACS). In this study, we explored whether METH abuse could aggravate the formation of VP in ApoE-/- mice fed with high cholesterol diet.

OBJECTIVE

The purpose of this study was to observe if chronic METH administration could aggravate vulnerable plaque (VP) formation in ApoE-/- mice fed with a highcholesterol diet.

METHODS

Male ApoE-/- mice fed with a high-cholesterol diet were intraperitoneally injected with normal saline (NS) or 8 mg/kg/day METH (M8) for 24 weeks. Body weight was monitored from baseline to 24 weeks at 2 weeks intervals. After 24 weeks of treatment, plasma lipid variables were measured. Movat's staining and immunohistochemical staining were performed on frozen sections of the aortic roots to calculate VP percentage and intraplaque hemorrhage (IPH) percentage and detect expression of NPY, vascular endothelial growth factor (VEGF), and CD31. In vitro, the expressions of Y2R, VEGF, and CD31 were detected by immunofluorescence staining in aortic endothelial cells incubated with PBS, 100μM METH, 10nmol NPY, or 100μM METH plus 10nmol NPY for 12 hours.

RESULTS

The CD31 positive area, percentage of IPH, VP, and the expressions of NPY and VEGF were significantly increased in the M8 group than in the NS group. In vitro, the expressions of Y2R, VEGF, and CD31 were significantly increased in the METH+NPY group than in the PBS, METH, and NPY groups and these effects could be blunted by treatment with a Y2R antagonist or DPPIV inhibitor.

CONCLUSION

Chronic METH administration could aggravate VP in ApoE-/- mice fed with a high-cholesterol diet, possibly through upregulating vascular NPY and VEGF expression and promoting angiogenesis and vessel rupture in atherosclerotic plaques. Our findings indicated that increased VP formation might contribute to the development of acute coronary syndrome post-chronic METH abuse by activating DPPIV/NPY/Y2R pathway.

Targeting Ferroptosis: A Novel Strategy for the Treatment of Atherosclerosis

Since ferroptosis was reported in 2012, its application prospects in various diseases have been widely considered, initially as a treatment direction for tumors. Recent studies have shown that ferroptosis is closely related to the occurrence and development of atherosclerosis. The primary mechanism is to affect the occurrence and development of atherosclerosis through intracellular iron homeostasis, ROS and lipid peroxide production and metabolism, and a variety of intracellular signaling pathways. Inhibition of ferroptosis is effective in inhibiting the development of atherosclerosis, and it can bring a new direction for treating atherosclerosis. In this review, we discuss the mechanism of ferroptosis and focus on the relationship between ferroptosis and atherosclerosis, summarize the different types of ferroptosis inhibitors that have been widely studied, and discuss some issues worthy of attention in the treatment of atherosclerosis by targeting ferroptosis.

RNA interference-based therapies for atherosclerosis: Recent advances and future prospects

Atherosclerosis represents a pathological state that affects the arterial system of the organism. This chronic, progressive condition is typified by the accumulation of atheroma within arterial walls. Modulation of RNA molecules through RNA-based therapies has expanded the range of therapeutic options available for neurodegenerative diseases, infectious diseases, cancer, and, more recently, cardiovascular disease (CVD). Presently, microRNAs and small interfering RNAs (siRNAs) are the most widely employed therapeutic strategies for targeting RNA molecules, and for regulating gene expression and protein production. Nevertheless, for these agents to be developed into effective medications, various obstacles must be overcome, including inadequate binding affinity, instability, challenges of delivering to the tissues, immunogenicity, and off-target toxicity. In this comprehensive review, we discuss in detail the current state of RNA interference (RNAi)-based therapies.

Progress of Ultrasound Techniques in the Evaluation of Carotid Vulnerable Plaque Neovascularization

BACKGROUND

The rupture and detachment of unstable plaques in the carotid artery can cause embolism in the cerebral artery, leading to acute cerebrovascular events. Intraplaque neovascularization (IPN) is a very important contributor to carotid plaque instability, and its evolution plays a key role in determining the outcome of vulnerable plaques. Ultrasound techniques, represented by contrast-enhanced ultrasound (CEUS) and superb microvascular imaging (SMI), are reported to be non-invasive, rapid, and effective techniques for the semi-quantitative or quantitative evaluation for IPN. Although ultrasound techniques have been widely applied in the detection of carotid plaque stability, it has been limited owing to the lack of unified IPN quantitative standards.

SUMMARY

This review summarizes the application and semi-quantitative/quantitative diagnostic standards of ultrasound techniques in evaluating IPN and looks forward to the prospects of the future research. With the development of novel techniques like artificial intelligence, ultrasound will offer appropriate selections for achieving more accuracy diagnosis.

KEY MESSAGES

A large number of studies have used CEUS and SMI to detect IPN and perform semi-quantitative grading to predict the occurrence of diseases such as stroke and to accurately assess drug efficacy based on rating changes. These studies have made great progress at this stage, but more accurate and intelligent quantitative imaging methods should become the future development goal.

Predictors of Inappropriately Rapid Coronary Lesion Progression in Patients Undergoing Percutaneous Coronary Interventions

Background

Patients undergoing percutaneous coronary intervention (PCI) may experience rapid atherosclerotic plaque progression in nontreated vessels that is unlikely to result from natural de novo atherosclerosis. We hypothesize that intra-lesion bleeding plays a central role in this process. The aim of this study is to investigate the factors that may contribute to accelerated narrowing in coronary diameter.

Methods

We reviewed 65 interventional procedures and their consequent staged PCIs and mapped the coronary tree into 16 segments (as divided by the American Heart Association), grading the percentage of stenosis in each segment and spotting the rapidly progressing lesions. Demographic, procedural, and laboratory data were recorded and analyzed.

Results

For the lesions that progressed rapidly in the time period between angiographies, the administration of eptifibatide intra-procedurally was associated with rapid progression of coronary lesions. Moreover, an increased white blood cell count prior to the index procedure was also associated with a trend toward rapid plaque progression.

Conclusions

In this hypothesis-generating study, treatment with a IIb/IIIa inhibitor in the index PCI was associated with an accelerated short-term progression of some of the nontreated lesions, suggesting that this mode of anti-aggregation therapy could facilitate plaque hemorrhage and consequent acceleration of coronary atherosclerosis in eroded plaques.

Extracellular Matrix Remodeling in Vascular Disease: Defining Its Regulators and Pathological Influence

Because of structural and cellular differences (ie, degrees of matrix abundance and cross-linking, mural cell density, and adventitia), large and medium-sized vessels, in comparison to capillaries, react in a unique manner to stimuli that induce vascular disease. A stereotypical vascular injury response is ECM (extracellular matrix) remodeling that occurs particularly in larger vessels in response to injurious stimuli, such as elevated angiotensin II, hyperlipidemia, hyperglycemia, genetic deficiencies, inflammatory cell infiltration, or exposure to proinflammatory mediators. Even with substantial and prolonged vascular damage, large- and medium-sized arteries, persist, but become modified by (1) changes in vascular wall cellularity; (2) modifications in the differentiation status of endothelial cells, vascular smooth muscle cells, or adventitial stem cells (each can become activated); (3) infiltration of the vascular wall by various leukocyte types; (4) increased exposure to critical growth factors and proinflammatory mediators; and (5) marked changes in the vascular ECM, that remodels from a homeostatic, prodifferentiation ECM environment to matrices that instead promote tissue reparative responses. This latter ECM presents previously hidden matricryptic sites that bind integrins to signal vascular cells and infiltrating leukocytes (in coordination with other mediators) to proliferate, invade, secrete ECM-degrading proteinases, and deposit injury-induced matrices (predisposing to vessel wall fibrosis). In contrast, in response to similar stimuli, capillaries can undergo regression responses (rarefaction). In summary, we have described the molecular events controlling ECM remodeling in major vascular diseases as well as the differential responses of arteries versus capillaries to key mediators inducing vascular injury.

Elevated Hemolysis Index is associated with higher risk of cardiovascular diseases

OBJECTIVES

In vivo hemolysis is associated with thromboembolism. Although an increased Hemolysis Index (HI) can be due to in vitro as well as in vivo hemolysis, both reflects a more fragile erythrocyte population. We therefore hypothesized that HI above upper reference limit would be associated with an increased risk of cardiovascular disease (CVD).

METHODS

We identified persons with two elevated HI (HI+) from blood samples analyzed at a university hospital laboratory from 2012 to 2017. We compared their risk of CVD with the risk in matched comparators with normal HI and from the general population. HI+ persons and comparators were followed from start date (date of the second elevated HI) until the first of the main outcome: CVD, emigration, death, or end of observation time on December 31, 2018.

RESULTS

In 43,102 unique HI+ persons, the risk of developing CVD was 40% higher compared with the general population and 13% higher compared with the matched blood sample cohort. HI+ was associated with a significantly increased cumulative incidence of both arterial and venous CVD compared with the matched blood sample cohort and the general population (respectively 47 and 14% for arterial CVD; 78 and 24% for venous CVD). Moreover, overall mortality risk was significantly higher in patients with HI+ than in the two comparator groups.

CONCLUSIONS

Elevated HI is associated with increased risk of arterial and venous CVD and with increased mortality. Our findings imply that HI may contribute as a CVD risk biomarker.

Biliverdin Reductase B Is a Plasma Biomarker for Intraplaque Hemorrhage and a Predictor of Ischemic Stroke in Patients with Symptomatic Carotid Atherosclerosis

BACKGROUND

Intraplaque hemorrhage (IPH) is a hallmark of atherosclerotic plaque instability. Biliverdin reductase B (BLVRB) is enriched in plasma and plaques from patients with symptomatic carotid atherosclerosis and functionally associated with IPH.

OBJECTIVE

We explored the biomarker potential of plasma BLVRB through (1) its correlation with IPH in carotid plaques assessed by magnetic resonance imaging (MRI), and with recurrent ischemic stroke, and (2) its use for monitoring pharmacotherapy targeting IPH in a preclinical setting.

METHODS

Plasma BLVRB levels were measured in patients with symptomatic carotid atherosclerosis from the PARISK study (n = 177, 5 year follow-up) with and without IPH as indicated by MRI. Plasma BLVRB levels were also measured in a mouse vein graft model of IPH at baseline and following antiangiogenic therapy targeting vascular endothelial growth factor receptor 2 (VEGFR-2).

RESULTS

Plasma BLVRB levels were significantly higher in patients with IPH (737.32 ± 693.21 vs. 520.94 ± 499.43 mean fluorescent intensity (MFI), p = 0.033), but had no association with baseline clinical and biological parameters. Plasma BLVRB levels were also significantly higher in patients who developed recurrent ischemic stroke (1099.34 ± 928.49 vs. 582.07 ± 545.34 MFI, HR = 1.600, CI [1.092-2.344]; p = 0.016). Plasma BLVRB levels were significantly reduced following prevention of IPH by anti-VEGFR-2 therapy in mouse vein grafts (1189 ± 258.73 vs. 1752 ± 366.84 MFI; p = 0.004).

CONCLUSIONS

Plasma BLVRB was associated with IPH and increased risk of recurrent ischemic stroke in patients with symptomatic low- to moderate-grade carotid stenosis, indicating the capacity to monitor the efficacy of IPH-preventive pharmacotherapy in an animal model. Together, these results suggest the utility of plasma BLVRB as a biomarker for atherosclerotic plaque instability.

Mitophagy in atherosclerosis: from mechanism to therapy

Mitophagy is a type of autophagy that can selectively eliminate damaged and depolarized mitochondria to maintain mitochondrial activity and cellular homeostasis. Several pathways have been found to participate in different steps of mitophagy. Mitophagy plays a significant role in the homeostasis and physiological function of vascular endothelial cells, vascular smooth muscle cells, and macrophages, and is involved in the development of atherosclerosis (AS). At present, many medications and natural chemicals have been shown to alter mitophagy and slow the progression of AS. This review serves as an introduction to the field of mitophagy for researchers interested in targeting this pathway as part of a potential AS management strategy.

Quantitative proteomic landscape of unstable atherosclerosis identifies molecular signatures and therapeutic targets for plaque stabilization

Atherosclerotic plaque rupture leading to myocardial infarction is a major global health burden. Applying the tandem stenosis (TS) mouse model, which distinctively exhibits the characteristics of human plaque instability/rupture, we use quantitative proteomics to understand and directly compare unstable and stable atherosclerosis. Our data highlight the disparate natures and define unique protein signatures of unstable and stable atherosclerosis. Key proteins and pathway networks are identified such as the innate immune system, and neutrophil degranulation. The latter includes calprotectin S100A8/A9, which we validate in mouse and human unstable plaques, and we demonstrate the plaque-stabilizing effects of its inhibition. Overall, we provide critical insights into the unique proteomic landscape of unstable atherosclerosis (as distinct from stable atherosclerosis and vascular tissue). We further establish the TS model as a reliable preclinical tool for the discovery and testing of plaque-stabilizing drugs. Finally, we provide a knowledge resource defining unstable atherosclerosis that will facilitate the identification and validation of long-sought-after therapeutic targets and drugs for plaque stabilization.

Intracoronary Imaging of Coronary Atherosclerotic Plaque: From Assessment of Pathophysiological Mechanisms to Therapeutic Implication

Atherosclerotic cardiovascular disease is the leading cause of morbidity and mortality worldwide. Several cardiovascular risk factors are implicated in atherosclerotic plaque promotion and progression and are responsible for the clinical manifestations of coronary artery disease (CAD), ranging from chronic to acute coronary syndromes and sudden coronary death. The advent of intravascular imaging (IVI), including intravascular ultrasound, optical coherence tomography and near-infrared diffuse reflectance spectroscopy has significantly improved the comprehension of CAD pathophysiology and has strengthened the prognostic relevance of coronary plaque morphology assessment. Indeed, several atherosclerotic plaque phenotype and mechanisms of plaque destabilization have been recognized with different natural history and prognosis. Finally, IVI demonstrated benefits of secondary prevention therapies, such as lipid-lowering and anti-inflammatory agents. The purpose of this review is to shed light on the principles and properties of available IVI modalities along with their prognostic significance.

BMP4 aggravates mitochondrial dysfunction of HRMECs

Mitochondria are important places for the oxidative phosphorylation of glucose and the maintenance of cell oxidation and antioxidant stability. However, mitochondrial dysfunction causes cell dysfunction. Meanwhile, retinal vascular endothelial cell dysfunction may cause vascular inflammation, hemorrhage, angiogenesis, and other manifestations. Our previous studies have shown that Bone morphogenetic protein 4 (BMP4) is an important target for the treatment of retinal neovascularization, but the mechanism remains unclear. Therefore, our study aims to observe the effects of BMP4 on vascular endothelial cells and hopes to provide a new target for diabetic retinopathy. 4-Hydroxynonenal (4HNE), a kind of lipid peroxide, was used to induce the oxidative stress model. Human retinal microvascular endothelial cells (HRMECs) were randomly divided into control, 4HNE, negative control, and siBMP4 groups. Si-BMP4 significantly reduced leukocyte adhesion and 4HNE-induced high ROS level and restored the mitochondrial membrane potential and OCR. This indicates that BMP4 plays an important role in inducing leukocyte adhesion, oxidative stress, and mitochondrial dysfunction. The relationship between BMP4 and retinal vascular endothelial cell dysfunction is preliminarily confirmed by this study. Mitochondrial dysfunction and oxidative stress may be involved in BMP4-mediated retinal vascular endothelial cell dysfunction.

Inhibition of ox-LDL-induced endothelial cell injury by LINC02381 knockdown through the microRNA-491-5p/transcription factor 7 axis

Atherosclerosis (AS) is a complex multifactorial and chronic inflammatory vascular disease that contributes to the development of cardiovascular diseases. Abnormal cellular proliferation in human umbilical vein endothelial cells (HUVECs) is a crucial element in AS development. In this study, we investigated the potential role of the long noncoding RNA LINC02381/microRNA (miR)-491-5p/transcription factor 7 (TCF7) axis in regulating HUVEC injury in 30 participants suffering from AS and 30 healthy control participants. We established an in vitro model of AS in HUVECs using oxidized low-density lipoprotein (ox-LDL), and measured cellular mRNA and protein levels of LINC02381, miR-491-5p, and TCF7 in serum samples using reverse transcription-quantitative polymerase chain reaction and Western blotting assays. We evaluated cell viability, apoptosis, and inflammation using Cell Counting Kit-8, flow cytometry, and enzyme-linked immunosorbent assays, respectively. Moreover, we analyzed apoptosis-related protein expression using western blotting analysis and determined the association between miR-491-5p and LINC02381 or TCF7 using dual-luciferase reporter assay, RNA pull-down, and rescue experiments. We observed that LINC02381 was elevated, while miR-491-5p was downregulated in serum samples from participants with AS and in ox-LDL-treated HUVECs. LINC02381 knockdown was protective against HUVEC injury via miR-491-5p inhibition, which is its downstream target. Rescue experiments further demonstrated that miR-491-5p alleviated HUVEC injury by modulating TCF7. Thus, LINC02381 knockdown ameliorated HUVEC injury by regulating the miR-491-5p/TCF7 axis, which provides new insights into AS treatment strategies.

Intracranial plaque with large lipid core is associated with embolic stroke of undetermined source

OBJECTIVE

To investigate an association between percentage lipid-rich necrotic core (LRNC) and an index ischemic stroke in an embolic stroke of undetermined source (ESUS) cohort.

METHODS

A total of 167 ESUS patients with 259 non-stenotic intracranial plaques including 155 ipsilateral and 104 contralateral to stroke were finally enrolled in the current analysis. The multi-dimensional parameters involving remodeling index (RI), plaque burden (PB), LRNC, discontinuity of plaque surface (DPS), intraplaque hemorrhage (IPH), and vulnerable plaque defined as presence of complicated plaque were evaluated by high-resolution magnetic resonance imaging.

RESULTS

We found that %LRNC was an independent predictor for ESUS in model 1 (OR: 2.574, 95% CI: 1.854-3.573, P < 0.001), and model 2 (OR: 2.550, 95% CI: 1.835-3.545, P < 0.001), but the association was not seen in PB. In receiver operating characteristic curve analysis, the discrimination of LRNC for ESUS was significantly superior to that of PB (absolute difference: 0.121, 95% CI: 0.056-0.205, P < 0.001). Importantly, a significantly positive synergy between the remodeling pattern and LRNC in response to plaque vulnerability was found by Sankey diagram (P for interaction = 0.001).

CONCLUSION

This is the first report that LRNC, beyond PB, may be correlated with an index ESUS, and a synergistic effect between positive remodeling and larger LRNC could promote plaque vulnerability. The findings suggest that a potential target subgroup may benefit from stroke prevention with intensive statin, although this must be confirmed in future.

Urotensin II Enhances Advanced Aortic Atherosclerosis Formation and Delays Plaque Regression in Hyperlipidemic Rabbits

Accumulated evidence shows that elevated urotensin II (UII) levels are associated with cardiovascular diseases. However, the role of UII in the initiation, progression, and regression of atherosclerosis remains to be verified. Different stages of atherosclerosis were induced in rabbits by a 0.3% high cholesterol diet (HCD) feeding, and either UII (5.4 μg/kg/h) or saline was chronically infused via osmotic mini-pumps. UII promoted atherosclerotic fatty streak formation in ovariectomized female rabbits (34% increase in gross lesion and 93% increase in microscopic lesion), and in male rabbits (39% increase in gross lesion). UII infusion significantly increased the plaque size of the carotid and subclavian arteries (69% increase over the control). In addition, UII infusion significantly enhanced the development of coronary lesions by increasing plaque size and lumen stenosis. Histopathological analysis revealed that aortic lesions in the UII group were characterized by increasing lesional macrophages, lipid deposition, and intra-plaque neovessel formation. UII infusion also significantly delayed the regression of atherosclerosis in rabbits by increasing the intra-plaque macrophage ratio. Furthermore, UII treatment led to a significant increase in NOX2 and HIF-1α/VEGF-A expression accompanied by increased reactive oxygen species levels in cultured macrophages. Tubule formation assays showed that UII exerted a pro-angiogenic effect in cultured endothelial cell lines and this effect was partly inhibited by urantide, a UII receptor antagonist. These findings suggest that UII can accelerate aortic and coronary plaque formation and enhance aortic plaque vulnerability, but delay the regression of atherosclerosis. The role of UII on angiogenesis in the lesion may be involved in complex plaque development.

Advances in neovascularization after diabetic ischemia

With the high incidence of diabetes around the world, ischemic complications cause a serious influence on people's production and living. Neovascularization plays a significant role in its development. Therefore, neovascularization after diabetic ischemia has aroused attention and has become a hot spot in recent years. Neovascularization is divided into angiogenesis represented by atherosclerosis and arteriogenesis characterized by coronary collateral circulation. When mononuclear macrophages successively migrate to the ischemia anoxic zone after ischemia or hypoxia, they induce the secretion of cytokines, such as vascular endothelial growth factor and hypoxia-inducible factor, activate signaling pathways such as classic Wnt and phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt) pathways, trigger oxidative stress response, activate endothelial progenitor cells or enter the glycolysis or lactic acid process and promote the formation of new blood vessels, remodeling them into mature blood vessels and restoring blood supply. However, the hypoglycemic condition has different impacts on neovascularization. Consequently, this review aimed to introduce the mechanisms of neovascularization after diabetic ischemia, increase our un-derstanding of diabetic ischemic complications and their therapies and provide more treatment options for clinical practice and effectively relieve patients' pain. It is believed that in the near future, neovascularization will bring more benefits and hope to patients with diabetes.

NOX4 mRNA correlates with plaque stability in patients with carotid artery stenosis

Carotid artery stenosis (CAS) develops from atherosclerotic lesions and plaques. Plaque rupture or stenosis may result in occlusion of the carotid artery. Accordingly, the asymptomatic disease becomes symptomatic, characterized by ischemic stroke or transient ischemic attacks, indicating an urgent need for better understanding of the underlying molecular mechanisms and eventually prevent symptomatic CAS. NOX4, a member of the NADPH oxidase family, has anti-atherosclerotic and anti-inflammatory properties in animal models of early atherosclerosis. We hypothesized that NOX4 mRNA expression is linked to protective mechanisms in CAS patients with advanced atherosclerotic lesions as well. Indeed, NOX4 mRNA expression is lower in patients with symptomatic CAS. A low NOX4 mRNA expression is associated with an increased risk of the development of clinical symptoms. In fact, NOX4 appears to be linked to plaque stability, apoptosis and plaque hemorrhage. This is supported by cleaved caspase-3 and glycophorin C and correlates inversely with plaque NOX4 mRNA expression. Even healing of a ruptured plaque appears to be connected to NOX4, as NOX4 mRNA expression correlates to fibrous cap collagen and is reciprocally related to MMP9 activity. In conclusion, low intra-plaque NOX4 mRNA expression is associated with an increased risk for symptomatic outcome and with reduced plaque stabilizing mechanisms suggesting protective effects of NOX4 in human advanced atherosclerosis.

Excessive Adventitial and Perivascular Vascularisation Correlates with Vascular Inflammation and Intimal Hyperplasia

Albeit multiple studies demonstrated that vasa vasorum (VV) have a crucial importance in vascular pathology, the informative markers and metrics of vascular inflammation defining the development of intimal hyperplasia (IH) have been vaguely studied. Here, we employed two rat models (balloon injury of the abdominal aorta and the same intervention optionally complemented with intravenous injections of calciprotein particles) and a clinical scenario (arterial and venous conduits for coronary artery bypass graft (CABG) surgery) to investigate the pathophysiological interconnections among VV, myeloperoxidase-positive (MPO⁺) clusters, and IH. We found that the amounts of VV and MPO⁺ clusters were strongly correlated; further, MPO⁺ clusters density was significantly associated with balloon-induced IH and increased at calciprotein particle-provoked endothelial dysfunction. Likewise, number and density of VV correlated with IH in bypass grafts for CABG surgery at the pre-intervention stage and were higher in venous conduits which more frequently suffered from IH as compared with arterial grafts. Collectively, our results underline the pathophysiological importance of excessive VV upon the vascular injury or at the exposure to cardiovascular risk factors, highlight MPO⁺ clusters as an informative marker of adventitial and perivascular inflammation, and propose another mechanistic explanation of a higher long-term patency of arterial grafts upon the CABG surgery.

Molecular Mechanisms Underlying Pathological and Therapeutic Roles of Pericytes in Atherosclerosis

Pericytes are multipotent mesenchymal stromal cells playing an active role in angiogenesis, vessel stabilisation, maturation, remodelling, blood flow regulation and are able to trans-differentiate into other cells of the mesenchymal lineage. In this review, we summarised recent data demonstrating that pericytes play a key role in the pathogenesis and development of atherosclerosis (AS). Pericytes are involved in lipid accumulation, inflammation, growth, and vascularization of the atherosclerotic plaque. Decreased pericyte coverage, endothelial and pericyte dysfunction is associated with intraplaque angiogenesis and haemorrhage, calcification and cholesterol clefts deposition. At the same time, pericytes can be used as a novel therapeutic target to promote vessel maturity and stability, thus reducing plaque vulnerability. Finally, we discuss recent studies exploring effective AS treatments with pericyte-mediated anti-atherosclerotic, anti-inflammatory and anti-apoptotic effects.

Dibutyl phthalate promotes angiogenesis in EA.hy926 cells through estrogen receptor-dependent activation of ERK1/2, PI3K-Akt, and NO signaling pathways

Dibutyl phthalate (DBP) is an endocrine disruptor that has been widely used in various products of human use. DBP exposure has been associated with reproductive and cardiovascular diseases and metabolic disorders. Although dysfunction of the vascular endothelium is responsible for many cardiovascular and metabolic diseases, little is known about the effects of DBP on human endothelium. In this study, we investigated the effect of three concentrations of DBP (10^-6, 10^-5, and 10^-4 M) on angiogenesis in human endothelial cell (EC) line EA.hy926 after acute exposure. Tube formation assay was used to investigate in vitro angiogenesis, whereas qRT-PCR was employed to measure mRNA expression. The effect of DBP on extracellular signal-regulated kinase 1/2 (ERK1/2), phosphatidylinositol 3-kinase (PI3K)-protein kinase B (Akt), and endothelial nitric oxide (NO) synthase (eNOS) activation was examined using Western blotting, whereas the Griess method was used to assess NO production. Results show that the 24-h-long exposure to 10^-4 M DBP increased endothelial tube formation, which was prevented by addition of U0126 (ERK1/2 inhibitor), wortmannin (PI3K-Akt inhibitor), and l-NAME (NOS inhibitor). Short exposure to 10^-4 M DBP (from 15 to 120 min) phosphorylated ERK1/2, Akt, and eNOS in different time points and increased NO production after 24 and 48 h of exposure. Application of nuclear estrogen receptor (ER) and G protein-coupled ER (GPER) inhibitors ICI 182,780 and G-15, respectively, abolished the DBP-mediated ERK1/2, Akt, and eNOS phosphorylation and increase in NO production. In this study, we report for the first time that DBP exerts a pro-angiogenic effect on human vascular ECs and describe the molecular mechanism involving ER- and GPER-dependent activation of ERK1/2, PI3K-Akt, and NO signaling pathways.

Mechanism of two alkaloids isolated from coral endophytic fungus for suppressing angiogenesis in atherosclerotic plaque in HUVEC

Atherosclerosis is a significant cause of many cardiovascular diseases. Oxidized low-density lipoproteins (ox-LDL) are crucial in developing atherosclerosis. In this study, we researched the effects of two alkaloids epi-aszonalenin A (EAA) and aszonalenin (AZN) of an endophytic fungus Aspergillus terreus C23-3 from coral Pavona, on ox-LDL-induced inflammation, apoptosis and angiogenesis in HUVEC, and evaluated related factors and mechanism. The results reveal that EAA and AZN inhibit HUVEC migration, invasion, angiogenesis and reactive oxygen species (ROS) accumulation on a non-cytotoxic basis. Then, EAA and AZN suppressed the ox-LDL-induced of LOX-1, VEGF protein expression, MAPK and PI3K/AKT pathways phosphorylation. Furthermore, AZN suppressed the ox-LDL-induced inflammatory factors (IL-6, IL-1β, and TNF-α), intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and VEGF receptor VEGFR-2 and platelet-derived growth factor PDGF. In addition, it inhibited ox-LDL-induced atherosclerosis by blocking inflammation and apoptosis through nuclear factor κB (NF-κB), cleaved-caspase-3 and Bax/Bcl-2 pathways. Molecular docking results confirm that the effect of AZN on atherosclerosis inhibitory activity may be attributed to hydrogen bonds formed into LOX-1 and VEGFR-2. These data indicate that EAA and AZN can effectively prevent ox-LDL-induced HUVEC damage and angiogenesis by inhibiting inflammation and apoptosis. Therefore, EAA and AZN may have potential beneficial effects in regulating atherosclerosis and plaque angiogenesis.

High Actin Expression in Thrombus of Acute Ischemic Stroke Can Be a Biomarker of Atherothrombotic Origin Stroke

Background

As the treatment target, the imaging information and histologic characteristics of the thrombus may differ according to the stroke subtype. This study aimed to provide the correlative study of stroke etiology with the non-contrast CT, and histological composition of retrieved clots in acute ischemic stroke (AIS).

Materials and Methods

A total of 94 patients with AIS who underwent the endovascular treatment with successfully retrieved clots from January 2017 to October 2020 were enrolled in the present study. Histological analysis was performed using hematoxylin and eosin (H&E) staining and immunostaining with CD3, CD20, CD105, and actin antibodies. CT obtained at the patients' admission was to measure the attenuation and volume of all thrombus.

Results

A total of 94 subjects were included in this study. Fifty-six patients were classified as cardioembolic (CE), and 38 were classified with large-artery atherosclerosis (LAA). The subjects with LAA tend to exhibit higher actin and CD105 levels, and lower Hounsfield Unit (HU) values than subjects with CE. After adjusting for confounders, the actin was positively correlated with CD105 but not with HU values. Logistics regression shows actin was valuable for the prediction of LAA (OR, 1.148; 95% CI, 1.075–1.227; p < 0.001), even adjusted for age, sex, and intervention type (OR, 1.129; 95% CI, 1.048–1.216; p = 0.001), CT density and CD105 (OR, 1.161; 95% CI, 1.056–1.277; p = 0.002). Actin levels have a strong accuracy in differentiating LAA from CE, especially combined with CT density and CD105, which yielded a sensitivity of 63.2%, a specificity of 89.3%, with the area under the curve (AUC) at 0.821 (95% CI, 0.731–0.912).

Conclusion

Our findings suggest that actin's level was a major factor differentiating atherothrombotic origin strokes from the cardioembolic stroke.

Clinical Trial Registration

ChiCTR2100051173.

Association between plaque vulnerability and neutrophil extracellular traps (NETs) levels: The Plaque At RISK study

Carotid atherosclerotic plaque rupture and its sequelae are among the leading causes of acute ischemic stroke. The risk of rupture and subsequent thrombosis is, among others, determined by vulnerable plaque characteristics and linked to activation of the immune system, in which neutrophil extracellular traps (NETs) potentially play a role. The aim of this study was to investigate how plaque vulnerability is associated with NETs levels. We included 182 patients from the Plaque At RISK (PARISK) study in whom carotid imaging was performed to measure plaque ulceration, fibrous cap integrity, intraplaque hemorrhage, lipid-rich necrotic core, calcifications and plaque volume. Principal component analysis generated a ‘vulnerability index’ comprising all plaque characteristics. Levels of the NETs marker myeloperoxidase-DNA complex were measured in patient plasma. The association between the vulnerability index and low or high NETs levels (dependent variable) was assessed by logistic regression. No significant association between the vulnerability index and NETs levels was detected in the total population (odds ratio 1.28, 95% confidence interval 0.90–1.83, p = 0.18). However, in the subgroup of patients naive to statins or antithrombotic medication prior to the index event, this association was statistically significant (odds ratio 2.08, 95% confidence interval 1.04–4.17, p = 0.04). Further analyses revealed that this positive association was mainly driven by intraplaque hemorrhage, lipid-rich necrotic core and ulceration. In conclusion, plaque vulnerability is positively associated with plasma levels of NETs, but only in patients naive to statins or antithrombotic medication prior to the index event.

Clinical risk scores for stroke correlate with molecular signatures of vulnerability in symptomatic carotid patients

Unstable carotid stenosis is an important cause of ischemic stroke, yet the basis of disease pathophysiology remains largely unknown. We hypothesized that integrated analyses of symptomatic carotid stenosis patients at increased stroke risk stratified by clinical scores, CAR and ABCD2, with transcriptomic and clinical data could improve identification of molecular pathways and targets for instability. We show that high CAR score reflects plaque instability processes related to intra-plaque hemorrhage, angiogenesis, inflammation, and foam cell differentiation, whereas ABCD2 associates with neutrophil-mediated immunity, foam cell differentiation, cholesterol transport, and coagulation. Repressed processes in plaques from high-risk patients were ossification, chondrocyte differentiation, SMC migration, and ECM organization. ABCB5 gene was found as the top upregulated in high-risk patient’s plaques, localized to macrophages in areas with neovascularization and intra-plaque hemorrhage. The link between ABCB5 and intra-plaque hemorrhage suggests its key role for plaque instability that warrants further exploration.

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We integrated stroke risk in carotid stenosis patients with plaque transcriptomics

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High CAR and ABCD2 scores reflect plaque instability processes and hemorrhage

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ABCB5 is upregulated in high-risk plaques, macrophages, and around neovessels

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CAR and ABCD2 capture vulnerable plaque features and improve risk stratification

Differential Gene Expression and Immune Cell Infiltration in Carotid Intraplaque Hemorrhage Identified Using Integrated Bioinformatics Analysis

Background

Intraplaque hemorrhage (IPH) is an important feature of unstable plaques and an independent risk factor for cardiovascular events. However, the molecular mechanisms contributing to IPH are incompletely characterized. We aimed to identify novel biomarkers and interventional targets for IPH and to characterize the role of immune cells in IPH pathogenesis.

Methods

The microarray dataset GSE163154 which contain IPH and non-IPH plaque samples was obtained from the Gene Expression Omnibus (GEO). R software was adopted for identifying differentially expressed genes (DEGs) and conducting functional investigation. The hub genes were carried by protein-protein interaction (PPI) network and were validated by the GSE120521 dataset. CIBERSORT deconvolution was used to determine differential immune cell infiltration and the relationship of immune cells and hub genes. We confirmed expression of proteins encoded by the hub genes by immunohistochemistry and western blotting in 8 human carotid endarterectomy samples with IPH and 8 samples without IPH (non-IPH).

Results

We detected a total of 438 differentially expressed genes (DEGs), of which 248 were upregulated and 190 were downregulated. DEGs were mainly involved in inflammatory related pathways, including neutrophil activation, neutrophil degranulation, neutrophil-mediated immunity, leukocyte chemotaxis, and lysosomes. The hub genes found through the method of degree in the PPI network showed that ITGB2 and ITGAM might play an important role in IPH. Receiver operating characteristic (ROC) results also showed a good performance of these two genes in the test and validation dataset. We found that the proportions of infiltrating immune cells in IPH and non-IPH samples differed, especially in terms of M0 and M2 macrophages. Immunohistochemistry and western blotting analysis showed that expression levels of ITGB2 and ITGAM increased significantly in carotid atherosclerotic plaques with IPH.

Conclusion

ITGB2 and ITGAM are key hub genes of IPH and may play an important role in the biological process of IPH. Our findings advance our understanding of the underlying mechanisms of IPH pathogenesis and provide valuable information and directions for future research into novel targets for IPH diagnosis and immunotherapy.

Associations between Circulating VEGFR2hi-Neutrophils and Carotid Plaque Burden in Patients Aged 40-64 without Established Atherosclerotic Cardiovascular Disease

Background

Neutrophils expressing vascular endothelial growth factor receptor (VEGFR) represent a distinct subtype of neutrophils with proangiogenic properties. The purpose of this study was to identify the interrelations between circulating CD16^hiCD11b^hiCD62L^loCXCR2^hiVEGFR2^hi-neutrophils and indicators of carotid plaque burden in patients without atherosclerotic cardiovascular diseases (ASCVD).

Methods

The study included 145 patients, 51.7% men and 48.3% women, median age—49.0 years. All patients underwent carotid duplex ultrasound scanning. The maximal carotid plaque thickness was used as an indicator of carotid plaque burden. Also, carotid intima-media thickness (cIMT) and femoral IMT were measured. The phenotyping of neutrophil subpopulations was executed by the flow cytometry via the Navios 6/2. Results. The subpopulation of VEGFR2^hi-neutrophils accounted for about 5% of the total pool of circulating neutrophils. A decrease in VEGFR2^hi-neutrophils with an increase in carotid plaque burden was statistically significant (p = 0.036). A decrease in VEGFR2^hi-neutrophils < 4.52% allowed to predict the presence of plaque with a maximum height > 2.1 mm (Q4), with sensitivity of 78.9% and specificity of 61.5% (AUC 0.693; 95% CI 0.575-0.811; p = 0.007). Inverse correlations were established between the carotid and femoral IMT and the absolute and relative number of VEGFR2^hi-neutrophils (p < 0.01).

Conclusion

In patients aged 40-64 years without established ASCVD, with an increase in indicators of the carotid plaque burden, a significant decrease in the proportion of circulating VEGFR2^hi-neutrophils was noticed. A decrease in the relative number of VEGFR2^hi-neutrophils of less than 4.52% made it possible to predict the presence of extent carotid atherosclerosis with sensitivity of 78.9% and specificity of 61.5%.

Impact of H-Type Hypertension on Intraplaque Neovascularization Assessed by Contrast-Enhanced Ultrasound

AIM

H-type hypertension is connected with carotid atherosclerotic plaques and stroke, whereas neovascularization is a dominant contributor to plaque vulnerability. However, the correlation between H-type hypertension and plaque vulnerability remains unclear. This study aims to explore the influence of H-type hypertension on intraplaque neovascularization (IPN).

METHODS

We enrolled 235 patients with carotid plaques into the investigation and classified them into four groups: H-type hypertension group, simple hypertension group, isolated hyperhomocysteinemia group, and control group. Contrast-enhanced ultrasound (CEUS) was performed on them and IPN was evaluated using semi-quantitative visual grading: grade 1 (no microbubbles or microbubbles limited to the adventitial side and/or shoulder of plaque) and, grade 2 (diffused microbubbles within plaque or microbubbles enter plaque core). To analyze the correlation between H-type hypertension and the degree of plaque enhancement, logistic regression was used.

RESULTS

Compared with those with CEUS grade 1 plaques, those with CEUS grade 2 plaques had higher frequency of ischemic stroke (29.0% vs. 45.1%, P＜0.05), hypertension (41.0% vs. 56.3%, P＜0.05), and H-type hypertension (18.0% vs. 29.6%, P＜0.05). No significant differences existed in plaque morphology, plaque echogenicity, and the severity of carotid artery stenosis between the degree of plaque enhancement (all P＞0.05). H-type hypertension (multivariate-adjusted OR: 3.036, 95% CI: 1.258-7.329) was independently connected with the degree of plaque enhancement even after adjusting for other covariates.

CONCLUSION

H-type hypertension is expressly connected with the degree of plaque enhancement and may facilitate plaque vulnerability. Our findings may offer a new insight for treating vulnerable plaque, lowering blood pressure, and lowering homocysteine equally crucial.

Functional Phenotypes of Intraplaque Macrophages and Their Distinct Roles in Atherosclerosis Development and Atheroinflammation

Macrophages are the key inflammatory cell type involved in all stages of atherosclerosis development and progression, as demonstrated by numerous studies. Correspondingly, macrophages are currently regarded as a promising therapeutic target for the development of new treatment approaches. The macrophage population is heterogeneous and dynamic, as these cells can switch between a number of distinct functional states with pro- and anti-atherogenic activity in response to various stimuli. An atherosclerotic plaque microenvironment defined by cytokine levels, cell-to-cell interactions, lipid accumulation, hypoxia, neoangiogenesis, and intraplaque haemorrhage may guide local macrophage polarization processes within the lesion. In this review, we discuss known functional phenotypes of intraplaque macrophages and their distinct contribution to ahteroinflammation.