Plaque angiogenesis and its relation to inflammation and atherosclerotic plaque destabilization

Neovascularization restructuring patterns in diabetic patients with coronary in stent restenosis: an in-vivo optical coherence tomography study

Patients with diabetes mellitus (DM) have an increased risk of in stent restenosis (ISR). Neovascularization (NV) is considered as a unique pathophysiology factor of ISR in diabetic patients. However, the restructuring patterns of in vivo human coronary NV and their relationship with ISR, especially in diabetic patients remain unclear. In this study, we aimed to investigate the NV structure differentiations between patients with and without DM after coronary stent implantation using optical coherence tomography (OCT). We included 136 patients with ISR (70 patients in DM group and 66 patients in non-DM group) who underwent OCT during coronary angiography follow-up. NVs were manually segmented, after which three-dimensional (3D) rendering of OCT images was conducted. NVs greater than 1 mm in length were classified as longitudinal running or coral tree types based on their 3D structures. NV structures were compared between DM and non-DM patients. The prevalence of the coral tree pattern NV in the DM group was 2.14-fold higher than in the non-DM group(p = 0.012). 47.14% of patients in the DM group and 51.51% of patients in the non-DM group presented longitudinal running NV (p = 0.610). The number of coral tree pattern NV was relatively higher in DM patients than in the non-DM patients (p = 0.019). However, the number of longitudinal running NV showed no difference between the two groups (p = 0.872). The normalized NV volume was significantly larger in the DM group (p = 0.008). Patients with coral tree pattern NV have thinner minimum fibrous cap thickness (p = 0.030). DM was the risk factor for coral tree pattern NV formation in ISR lesions after adjustment for other factors. NV with specific restructuring patterns, such as longitudinal running and coral tree patterns, can be identified in ISR lesions. NV with a coral tree pattern, characterized by higher leakiness and immaturity, is more commonly found in patients with DM and is associated with tissue instability in ISR. Accurate and feasible imaging modalities for NV might offer promising opportunities to evaluate NV and prevent progression of ISR in diabetic patients.

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.

Dual-Function Nanoscale Coordination Polymer Nanoparticles for Targeted Diagnosis and Therapeutic Delivery in Atherosclerosis

Atherosclerosis is the primary cause of cardiovascular events such as heart attacks and strokes. However, current medical practice lacks non-invasive, reliable approaches for both imaging atherosclerotic plaques and delivering therapeutic agents directly therein. Here, a biocompatible and biodegradable pH-responsive nanoscale coordination polymers (NCPs) based theranostic system is reported for managing atherosclerosis. NCPs are synthesized with a pH-responsive benzoic-imine (BI) linker and Gd3+. Simvastatin (ST), a statin not used for lowering blood cholesterol but known for its anti-inflammatory and antioxidant effects in mice, is chosen as the model drug. By incorporating ST into the hydrophobic domain of a lipid bilayer shell on NCPs surfaces, ST/NCP-PEG nanoparticles are created that are designed for dual purposes: they diagnose and treat atherosclerosis. When administered intravenously, they target atherosclerotic plaques, breaking down in the mild acidic microenvironment of the plaque to release ST, which reduces inflammation and oxidative stress, and Gd-complexes for MR imaging of the plaques. ST/NCP-PEG nanoparticles show efficacy in slowing the progression of atherosclerosis in live models and allow for simultaneous in vivo monitoring without observed toxicity in major organs. This positions ST/NCP-PEG nanoparticles as a promising strategy for the spontaneous diagnosis and treatment of atherosclerosis.

Notoginsenoside R1 decreases intraplaque neovascularization by governing pericyte-endothelial cell communication via Ang1/Tie2 axis in atherosclerosis

Atherosclerosis represents the major cause of mortality worldwide and triggers higher risk of acute cardiovascular events. Pericytes-endothelial cells (ECs) communication is orchestrated by ligand-receptor interaction generating a microenvironment which results in intraplaque neovascularization, that is closely associated with atherosclerotic plaque instability. Notoginsenoside R1 (R1) exhibits anti-atherosclerotic bioactivity, but its effect on angiogenesis in atherosclerotic plaque remains elusive. The aim of our study is to explore the therapeutic effect of R1 on vulnerable plaque and investigate its potential mechanism against intraplaque neovascularization. The impacts of R1 on plaque stability and intraplaque neovascularization were assessed in ApoE-/- mice induced by high-fat diet. Pericytes-ECs direct or non-direct contact co-cultured with VEGF-A stimulation were used as the in vitro angiogenesis models. Overexpressing Ang1 in pericytes was performed to investigate the underlying mechanism. In vivo experiments, R1 treatment reversed atherosclerotic plaque vulnerability and decreased the presence of neovessels in ApoE-/- mice. Additionally, R1 reduced the expression of Ang1 in pericytes. In vitro experiments demonstrated that R1 suppressed pro-angiogenic behavior of ECs induced by pericytes cultured with VEGF-A. Mechanistic studies revealed that the anti-angiogenic effect of R1 was dependent on the inhibition of Ang1 and Tie2 expression, as the effects were partially reversed after Ang1 overexpressing in pericytes. Our study demonstrated that R1 treatment inhibited intraplaque neovascularization by governing pericyte-EC association via suppressing Ang1-Tie2/PI3K-AKT paracrine signaling pathway. R1 represents a novel therapeutic strategy for atherosclerotic vulnerable plaques in clinical application.

Recent progress in biomimetic nanomedicines based on versatile targeting strategy for atherosclerosis therapy

Atherosclerosis (AS) is considered to be one of the major causes of cardiovascular disease. Its pathological microenvironment is characterised by increased production of reactive oxygen species, lipid oxides, and excessive inflammatory factors, which accumulate at the monolayer endothelial cells in the vascular wall to form AS plaques. Therefore, intervention in the pathological microenvironment would be beneficial in delaying AS. Researchers have designed biomimetic nanomedicines with excellent biocompatibility and the ability to avoid being cleared by the immune system through different therapeutic strategies to achieve better therapeutic effects for the characteristics of AS. Biomimetic nanomedicines can further enhance delivery efficiency and improve treatment efficacy due to their good biocompatibility and ability to evade clearance by the immune system. Biomimetic nanomedicines based on therapeutic strategies such as neutralising inflammatory factors, ROS scavengers, lipid clearance and integration of diagnosis and treatment are versatile approaches for effective treatment of AS. The review firstly summarises the targeting therapeutic strategy of biomimetic nanomedicine for AS in recent 5 years. Biomimetic nanomedicines using cell membranes, proteins, and extracellular vesicles as carriers have been developed for AS.

The JMJD family of histone demethylase and their intimate links to cardiovascular disease

The incidence rate and mortality rate of cardiovascular disease rank first in the world. It is associated with various high-risk factors, and there is no single cause. Epigenetic modifications, such as DNA methylation or histone modification, actively participate in the initiation and development of cardiovascular diseases. Histone lysine methylation is a type of histone post-translational modification. The human Jumonji C domain (JMJD) protein family consists of more than 30 members. JMJD proteins participate in many key nuclear processes and play a key role in the specific regulation of gene expression, DNA damage and repair, and DNA replication. Importantly, increasing evidence shows that JMJD proteins are abnormally expressed in cardiovascular diseases, which may be a potential mechanism for the occurrence and development of these diseases. Here, we discuss the key roles of JMJD proteins in various common cardiovascular diseases. This includes histone lysine demethylase, which has been studied in depth, and less-studied JMJD members. Furthermore, we focus on the epigenetic changes induced by each JMJD member, summarize recent research progress, and evaluate their relationship with cardiovascular diseases and therapeutic potential.

Myocardial Expression of Pluripotency, Longevity, and Proinflammatory Genes in the Context of Hypercholesterolemia and Statin Treatment

Background: This study sought to assess the effect of statin therapy on myocardial inflammation in a White New Zealand rabbit model of atherogenesis. Methods: The mRNA expression levels of pro-inflammatory, pluripotency, and aging-related markers were quantified following a controlled feeding protocol and statin treatments. Results: Following high-cholesterol diet induction, we observed significant upregulation in the myocardial mRNA levels of MYD88, NF-κB, chemokines (CCL4, CCL20, and CCR2), IFN-γ, interleukins (IL-1β, IL-2, IL-4, IL-8, IL-10, and IL-18), and novel markers (klotho, KFL4, NANOG, and HIF1α). In contrast, HOXA5 expression was diminished following a hyperlipidemic diet. Both statin treatments significantly influenced the markers studied. Nevertheless, rosuvastatin administration resulted in a greater reduction in MYD88, NF-kB, chemokines (CCL4, CCL20, and CCR2), and interleukins IL-1β, IL-8, KLF4, NANOG, and HIF1α than fluvastatin. Fluvastatin, on the other hand, led to a stronger decrease in IL-4. Downregulation of IL-2 and IL-18 and upregulation of IFNβ and HOXA5 were comparable between the two statins. Notably, rosuvastatin had a stronger effect on the upregulation of klotho and IL-10. Conclusion: Overall, statin therapy significantly attenuated inflammatory, pluripotency, and klotho expression in myocardial tissue under atherogenic conditions. Our findings also highlight the differential efficacy of rosuvastatin over fluvastatin in curtailing proatherogenic inflammation, which could have profound implications for the clinical management of cardiovascular disease.

An Updated Review on the Significance of DNA and Protein Methyltransferases and De-methylases in Human Diseases: From Molecular Mechanism to Novel Therapeutic Approaches

Epigenetic mechanisms are crucial in regulating gene expression. These mechanisms include DNA methylation and histone modifications, like methylation, acetylation, and phosphorylation. DNA methylation is associated with gene expression suppression; however, histone methylation can stimulate or repress gene expression depending on the methylation pattern of lysine or arginine residues on histones. These modifications are key factors in mediating the environmental effect on gene expression regulation. Therefore, their aberrant activity is associated with the development of various diseases. The current study aimed to review the significance of DNA and histone methyltransferases and demethylases in developing various conditions, like cardiovascular diseases, myopathies, diabetes, obesity, osteoporosis, cancer, aging, and central nervous system conditions. A better understanding of the epigenetic roles in developing diseases can pave the way for developing novel therapeutic approaches for affected patients.

Role of sirtuins in attenuating plaque vulnerability in atherosclerosis

Atherosclerosis is characterized by the development of intimal plaque, thrombosis, and stenosis of the vessel lumen causing decreased blood flow and hypoxia precipitating angina. Chronic inflammation in the stable plaque renders it unstable and rupture of unstable plaques results in the formation of emboli leading to hypoxia/ischemia to the organs by occluding the terminal branches and precipitate myocardial infarction and stroke. Such delibitating events could be controlled by the strategies that prevent plaque development or plaque stabilization. Despite the use of statins to stabilize plaques, there is a need for novel targets due to continuously increasing cases of cardiovascular events. Sirtuins (SIRTs), a family of signaling proteins, are involved in sustaining genome integrity, DNA damage response and repair, modulating oxidative stress, aging, inflammation, and energy metabolism. SIRTs play a critical role in modulating inflammation and involves in the development and progression of atherosclerosis. The role of SIRTs in relation to atherosclerosis and plaque vulnerability is scarcely discussed in the literature. Since SIRTs regulate oxidative stress, inflammation, and aging, they may also regulate plaque progression and vulnerability as these molecular mechanisms underlie the pathogenesis of plaque development, progression, and vulnerability. This review critically discusses the role of SIRTs in plaque progression and vulnerability and the possibility of targeting SIRTs to attenuate plaque rupture, focusing on the highlights in genomics, molecular pathways, and cell types involved in the underlying pathophysiology.

Association between inflammatory burden index and all-cause mortality in the general population aged over 45 years: Data from NHANES 2005-2017

BACKGROUND AND AIM

The objective of this study was to investigate the association between inflammatory burden index (IBI) and all-cause mortality in the general population aged over 45 years.

METHODS AND RESULTS

The study included 8827 participants from the National Health and Examination Nutrition Survey (NHANES) who were aged over 45 years. The IBI was calculated using three markers: C-reaction protein × neutrophil/lymphocyte, and all the participants were classified into four groups (Quartile 1: IBI ≤0.178, N = 2206; Quartile 2: 0.178 1.099, 2207). Cox proportional hazards regression models were used to estimate hazard ratios (HR) and 95 % confidence interval (CI) for the association between IBI and all-cause mortality. During a median follow-up of 129 month, 2431 deaths occurred. The all-cause mortality rate in Quartile 1, Quartile 2, Quartile 3 and Quartile 4 was 14.76 %, 17.67 %, 23.18 % and 29.69 %, respectively (p < 0.001). After adjustment for demographic, and potential clinical factors, higher IBI was significantly associated with an increased risk of all-cause mortality (Quartile 3 vs. Quartile 1: HR = 1.26, 95 % CI: 1.08 to 1.46, p = 0.003; Quartile 4 vs. Quartile 1: HR = 1.59, 95 % CI: 1.40 to 1.80, p < 0.001). Furthermore, the results of the restricted cubic spline analysis suggested that the association between IBI and all-cause mortality was nonlinear and positive, without specific threshold value.

CONCLUSIONS

This study supports that higher IBI is associated with an increased risk of all-cause mortality in the general population aged over 45 years.

Integrated systems biology approach identifies gene targets for endothelial dysfunction

Endothelial dysfunction (ED) is critical in the development and progression of cardiovascular (CV) disorders, yet effective therapeutic targets for ED remain elusive due to limited understanding of its underlying molecular mechanisms. To address this gap, we employed a systems biology approach to identify potential targets for ED. Our study combined multi omics data integration, with siRNA screening, high content imaging and network analysis to prioritise key ED genes and identify a pro- and anti-ED network. We found 26 genes that, upon silencing, exacerbated the ED phenotypes tested, and network propagation identified a pro-ED network enriched in functions associated with inflammatory responses. Conversely, 31 genes ameliorated ED phenotypes, pointing to potential ED targets, and the respective anti-ED network was enriched in hypoxia, angiogenesis and cancer-related processes. An independent screen with 17 drugs found general agreement with the trends from our siRNA screen and further highlighted DUSP1, IL6 and CCL2 as potential candidates for targeting ED. Overall, our results demonstrate the potential of integrated system biology approaches in discovering disease-specific candidate drug targets for endothelial dysfunction.

Transfection of Vein Grafts with Early Growth Response Factor-1 Oligodeoxynucleotide Decoy: Effects on Stem-Cell Genes and Toll-like Receptor-Mediated Inflammation

The long-term patency of vein grafts is challenged by intimal hyperplasia. We sought to explore the intricate relationships between the transcription factor Egr-1, toll-like receptors (TLRs), and stem cell genes and also assessed oligodeoxynucleotide decoys (ODNs) as a strategy to prevent vein graft failures. A total of 42 New Zealand white rabbits were fed hyperlipidemic chow and classified into three groups. A double-stranded Egr-1 ODN was synthesized and infused in vein grafts prior to anastomosis with the common carotid artery. All vein grafts were retrieved at the conclusion of the predefined experimental period. Real-time quantitative polymerase chain reaction was performed to estimate expression patterns for several genes of interest. MYD88, TLR2-4, TLR8, NF-kB, TNF-α, IFNβ, and IFNγ; chemokines CCL4, CCL20, CCR2; numerous interleukins; and stem cell genes KFL4, NANOG, HOXA5, and HIF1α were universally downregulated in the ODN arm compared with the controls. By understanding these multifaceted interactions, our study offers actionable insights that may pave the way for innovative interventions in vascular reconstructions.

Micro- and Macrovascular Effects of Inflammation in Peripheral Artery Disease-Pathophysiology and Translational Therapeutic Approaches

Inflammation has a critical role in the development and progression of atherosclerosis. On the molecular level, inflammatory pathways negatively impact endothelial barrier properties and thus, tissue homeostasis. Conformational changes and destruction of the glycocalyx further promote pro-inflammatory pathways also contributing to pro-coagulability and a prothrombotic state. In addition, changes in the extracellular matrix composition lead to (peri-)vascular remodelling and alterations of the vessel wall, e.g., aneurysm formation. Moreover, progressive fibrosis leads to reduced tissue perfusion due to loss of functional capillaries. The present review aims at discussing the molecular and clinical effects of inflammatory processes on the micro- and macrovasculature with a focus on peripheral artery disease.

The Double-Edged Sword of Erythrocytes in Health and Disease via Their Adhesiveness

Their widespread presence throughout the vasculature, coupled with their reactivity, and thereby to their potential to release reactive oxidative species, or to utilize their anti-oxidative capacities, has promoted much discussion of the role(s) of red blood cells (RBCs) in the progression of health or, alternatively, a wide range of disease states. Moreover, these role(s) have been linked to the development of adhesiveness and, in fact, thereby to the essential pathway to their eventual clearance, e.g., by macrophages in the spleen. These disparate roles coupled with the mechanisms involved are reviewed and given. Following an analysis, novel perspectives are provided; these perspectives can lead to novel assays for identifying the potential for RBC adhesiveness as suggested herein. We describe this paradigm, that involves RBC adhesiveness, hemolysis, and ghost formation, with examples including, inter alia, the progression of atherosclerosis and the suppression of tumor growth along with other disease states.

H-type hypertension is a risk factor for chronic total coronary artery occlusion: a cross-sectional study from southwest China

BACKGROUND

Chronic total coronary occlusion (CTO) is serious and the "last bastion" of percutaneous coronary intervention. Hypertension and hyperhomocysteinemia (HHCY) are synergistic and significantly increase cardiovascular event risk. The relationship between H-type hypertension and CTO remains unclear; thus, this cross-sectional study investigated this potential association.

METHODS

Between January 2018 and June 2022, 1446 individuals from southwest China were recruited to participate in this study. CTO was defined as complete coronary artery occlusion persisting for over three months. H-type hypertension was defined as hypertension with plasma homocysteine levels ≥ 15 µmol/L. Multivariate logistic regression models were applied to assess the association between H-type hypertension and CTO. Receiver operating characteristic (ROC) curves were generated to determine the accuracy of H-type hypertension in predicting CTO.

RESULTS

Of the 1446 individuals, 397 had CTO, and 545 had H-type hypertension. After multivariate adjustment, the odds ratio (OR) for CTO in individuals with H-type hypertension was 2.3-fold higher (95% CI 1.01-5.26) than that in healthy controls. The risk of CTO is higher in individuals with H-type hypertension than in those with isolated HHCY and hypertension. The area under the ROC curve for CTO was 0.685 (95% CI, 0.653-0.717) for H-type hypertension.

CONCLUSIONS

In southwest China, H-type hypertension is significantly related to the occurrence of CTO.

TRIAL REGISTRATION

This retrospective study was registered with the Chinese Clinical Trials Registry ( http://www.chictr.org.cn , ChiCTR2100050519.2.2).

Development of gene model combined with machine learning technology to predict for advanced atherosclerotic plaques

BACKGROUND

Atherosclerosis, as a major cause of stroke, is responsible for a quarter of deaths worldwide. In particular, rupture of late-stage plaques in large vessels such as the carotid artery can lead to serious cardiovascular disease. The aim of our study was to establish a genetic model combined with machining leaning techniques to screen out gene signatures and predict for advanced atherosclerosis plaques.

METHODS

The microarray dataset GSE28829 and GSE43292 which were publicly obtained from the Gene Expression Omnibus database were utilized to screen for potential predictive genes. Differentially expressed genes (DEGs) were identified by using the "limma" R package. Gene Ontology (GO) and Kyoto Encyclopedia of Genes Genomes (KEGG) analyses of these DEGs were performed by Metascape. Later, Random Forest (RF) algorithm was applied to further screen out top-30 genes which contribute the most. The expression data of top 30-DEGs were converted into a "Gene Score". Finally, we developed a model based on artificial neural network (ANN) to predict advanced atherosclerotic plaques. The model later was validated in an independent test dataset GSE104140.

RESULTS

A total of 176 DEGs were identified in the training datasets. GO and KEGG enrichment analysis revealed that these genes were enriched in leukocyte-mediated immune response, cytokine- cytokine interactions, and immunoinflammatory signaling. Further, top-30 genes (including 25 upregulated and 5 downregulated DEGs) were screened as predictors by RF algorithm. The predictive model was developed with a significantly predictive value (AUC = 0.913) in the training datasets, and was validated with an independent dataset GSE104140 (AUC = 0.827).

CONCLUSION

In present study, our prediction model was established and showed satisfactory predictive power in both training and test datasets. In addition, this is the first study adopted bioinformatics methods combined with machine learning techniques (RF and ANN) to explore and predict for the advanced atherosclerotic plaques. However, further investigations were needed to verify the screened DEGs and predictive effectiveness of this model.

Extracellular vesicles and atherosclerotic peripheral arterial disease

Atherogenesis involves a complex multifactorial process including chronic inflammation that requires the participation of several cell types and molecules. In addition to their role in vascular homeostasis, extracellular vesicles also appear to play an important role in atherogenesis, including monocyte transmigration and foam cell formation, SMC proliferation and migration, leukocyte transmigration, and thrombosis. Peripheral arterial disease, a major form of peripheral vascular disease, is characterized by structural or functional impairment of peripheral arterial supply, often secondary to atherosclerosis. Elevated levels of extracellular vesicles have been demonstrated in patients with peripheral arterial disease and implicated in the development of atherosclerosis within peripheral vascular beds. However, extracellular vesicles also appear capable of delivering cargo with atheroprotective effects. This capability has been exploited in vesicles engineered to carry content capable of neovascularization, suggesting potential for therapeutic angiogenesis. This dual capacity holds substantial promise for diagnosis and therapy, including possibly limb- and life-saving options for peripheral arterial disease management.

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.

Progress in Stimuli-Responsive Biomaterials for Treating Cardiovascular and Cerebrovascular Diseases

Cardiovascular and cerebrovascular diseases (CCVDs) describe abnormal vascular system conditions affecting the brain and heart. Among these, ischemic heart disease and ischemic stroke are the leading causes of death worldwide, resulting in 16% and 11% of deaths globally. Although several therapeutic approaches are presented over the years, the continuously increasing mortality rates suggest the need for more advanced strategies for their treatment. One of these strategies lies in the use of stimuli-responsive biomaterials. These "smart" biomaterials can specifically target the diseased tissue, and after "reading" the altered environmental cues, they can respond by altering their physicochemical properties and/or their morphology. In this review, the progress in the field of stimuli-responsive biomaterials for CCVDs in the last five years, aiming at highlighting their potential as early-stage therapeutics in the preclinical scenery, is described.

Targeting the Microenvironment of Vulnerable Atherosclerotic Plaques: An Emerging Diagnosis and Therapy Strategy for Atherosclerosis

Atherosclerosis is considered one of the primary causes of cardiovascular diseases (CVDs). Unpredictable rupture of the vulnerable atherosclerotic plaques triggers adverse cardiovascular events such as acute myocardial syndrome and even sudden cardiac death. Therefore, assessing the vulnerability of atherosclerotic plaques and early intervention are of significance in reducing CVD mortality. Nanomedicine possesses tremendous advantages in achieving the integration of the diagnosis and therapy of atherosclerotic plaques because of its magnetic, optical, thermal, and catalytic properties. Based on the pathological characteristics of vulnerable plaques, stimuli-responsive nanoplatforms and surface-functionalized nanoagents are designed and have drawn great attention for accomplishing the precise imaging and treatment of vulnerable atherosclerotic plaques due to their superior properties, such as high bioavailability, lesion-targeting specificity, on-demand cargo release, and low off-target damage. Here, the characteristics of vulnerable plaques are generalized, and some targeted strategies for boosting the accuracy of plaque vulnerability evaluation by imaging and the efficacy of plaque stabilization therapy (including antioxidant therapy, macrophage depletion therapy, regulation of lipid metabolism therapy, anti-inflammation therapy, etc.) are systematically summarized. In addition, existing challenges and prospects in this field are discussed, and it is believed to provide new thinking for the diagnosis and treatment of CVDs in the near future.

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.

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.

Clinical Parameters and Epigenetic Biomarkers of Plaque Vulnerability in Patients with Carotid Stenosis

Atheromatous disease is the first cause of death and dependency in developed countries and carotid artery atherosclerosis is one of the main causes of severe ischaemic strokes. Current management strategies are mainly based on the degree of stenosis and patient selection has limited accuracy. This information could be complemented by the identification of biomarkers of plaque vulnerability, which would permit patients at greater and lesser risk of stroke to be distinguished, thus enabling a better selection of patients for surgical or intensive medical treatment. Although several circulating protein-based biomarkers with significance for both the diagnosis of carotid artery disease and its prognosis have been identified, at present, none have been clinically implemented. This review focuses especially on the most relevant clinical parameters to take into account in routine clinical practice and summarises the most up-to-date data on epigenetic biomarkers of carotid atherosclerosis and plaque vulnerability.

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.

Neutrophil-to-lymphocyte ratio is associated with carotid intraplaque neovascularization in asymptomatic carotid stenosis patients

BACKGROUND AND PURPOSE

Neutrophil-to-lymphocyte ratio (NLR) has been suggested as an available systemic inflammatory biomarker. This study aims to evaluate whether intraplaque neovascularization assessed by contrast-enhanced ultrasound (CEUS) is associated with NLR in asymptomatic carotid stenosis patients.

MATERIALS AND METHODS

One hundred and forty-four asymptomatic patients with carotid luminal stenosis >30% were assessed using contrast-enhanced ultrasound imaging. The contrast enhancement within the plaque was classified on a visual semiquantitative grading scale. The data collected included the patient's risk factors, laboratory results, cardiovascular disease history, and drug use history. Univariate and multivariate analyses were assessed to identify independent factors related to intraplaque neovascularization with adjustment for potential confounders.

RESULTS

Patients with CEUS grade 2 plaques had a higher level of LDL-C (p < .001), neutrophil count (p < .001), and blood glucose (p = .005), but lower level of lymphocyte count (p = .021). The presence of grade 2 plaques was significantly associated with high NLR values (OR 1.21, 95% CI 1.03-1.43, p = .017). Patients were divided into four groups according to the quartile of NLR values. Compared to the patients in the first quartile of NLR (<1.73), the patients in the fourth NLR quartile (≥3.38) were characterized by the most prevalence of CEUS grade 2 plaques (OR 4.55, 95% CI 1.69-12.25, p = .003). Multivariate logistic regression analysis after adjusting various variables demonstrated NLR remained an independent risk factor for the presence of CEUS grade 2 plaques.

CONCLUSION

Intraplaque neovascularization is significantly associated with NLR in asymptomatic carotid stenosis patients.

Interfering in the ALK1 Pathway Results in Macrophage-Driven Outward Remodeling of Murine Vein Grafts

Aims

Vein grafts are frequently used to bypass coronary artery occlusions. Unfortunately, vein graft disease (VGD) causes impaired patency rates. ALK1 mediates signaling by TGF-β via TGFβR2 or BMP9/10 via BMPR2, which is an important pathway in fibrotic, inflammatory, and angiogenic processes in vascular diseases. The role of the TGF-β pathway in VGD is previously reported, however, the contribution of ALK1 signaling is not known. Therefore, we investigated ALK1 signaling in VGD in a mouse model for vein graft disease using either genetic or pharmacological inhibition of the Alk1 signaling.

Methods and Results

Male ALK1 heterozygous (ALK1^+/−), control C57BL/6, as well as hypercholesterolemic ApoE3^*Leiden mice, underwent vein graft surgery. Histologic analyses of ALK1^+/− vein grafts demonstrated increased outward remodeling and macrophage accumulation after 28 days. In hypercholesterolemic ApoE3^*Leiden mice receiving weekly ALK1-Fc injections, ultrasound imaging showed 3-fold increased outward remodeling compared to controls treated with control-Fc, which was confirmed histologically. Moreover, ALK1-Fc treatment reduced collagen and smooth muscle cell accumulation, increased macrophages by 1.5-fold, and resulted in more plaque dissections. No difference was observed in intraplaque neovessel density. Flow cytometric analysis showed increased systemic levels of Ly6C^High monocytes in ALK1-Fc treated mice, supported by in vitro increased MCP-1 and IL-6 production of LPS-stimulated and ALK1-Fc-treated murine monocytes and macrophages.

Conclusion

Reduced ALK1 signaling in VGD promotes outward remodeling, increases macrophage influx, and promotes an unstable plaque phenotype.

Translational Perspective

Vein graft disease (VGD) severely hampers patency rates of vein grafts, necessitating research of key disease-driving pathways like TGF-β. The three-dimensional nature of VGD together with the multitude of disease driving factors ask for a comprehensive approach. Here, we combined in vivo ultrasound imaging, histological analyses, and conventional in vitro analyses, identifying the ambiguous role of reduced ALK1 signaling in vein graft disease. Reduced ALK1 signaling promotes outward remodeling, increases macrophage influx, and promotes an unstable plaque phenotype in murine vein grafts. Characterization of in vivo vascular remodeling over time is imperative to monitor VGD development and identify new therapies.

Bioactive components to inhibit foam cell formation in atherosclerosis

BACKGROUND

The production of lipid-laden cells in macrophages after significant ingestion of oxidized low-density lipoprotein is considered the most critical phase in the creation of atherosclerotic lesions, which is known as foam cell formation. Targeting foam cell development to find a potential therapeutic strategy for the management of atherosclerosis has yielded numerous promising outcomes. Multiple variables influence foam cell growth, including scavenger receptor expression, cholesterol transporter expression acyl CoA: cholesterol acyltransferase activity, and neutral cholesteryl ester hydrolase activity. Plants used during herbal therapy have been shown to assist with a variety of ailments.

RESULT

In this study, we found medicinal plants and their bioactive components suppress foam cell formation in a variety of ways; some inhibit cholesterol transporter and lectin-like oxidized low-density lipoprotein receptor-1 upregulation, while others inhibit the function of acyl CoA: cholesterol acyltransferase activity, and neutral cholesteryl ester hydrolase activity.

CONCLUSION

Recent study findings related to the synthesis of the new active component from plant sources by focusing on the typical process involved in the generation of foam cells. We're also looking at using a cellular target-based therapeutic approach to generate novel plant-based medications for the cure of atherosclerosis.

Targeting Inflammation in the Diagnosis, Management, and Prevention of Cardiovascular Diseases

Inflammation plays an important role in the development and progression of cardiovascular diseases (CVDs). Hypertension and hyperlipidemia are the key risk factors of CVDs and induce inflammation in the heart and vessels. Unhealthy diet, infection, and smoking coupled with genetic factors lead to the development of CVDs as well as induce inflammation. Risk factors of CVDs such as hypertension and hyperlipidemia along with diabetes activate nuclear factor kappa B, which regulates the transcription of immunoglobulin free light chain (FLC) κ in B cells and the production of multiple inflammatory molecules, leading to inflammation. FLCs are novel biomarkers of inflammation, and their levels have been associated with overall mortality in a general population and with cardiovascular outcomes. In this review, the role of inflammation in the pathogenesis of CVDs, new biomarkers of inflammation, and dietary options counterbalancing inflammatory processes, such as the polyphenol-rich French maritime pine bark extract Pycnogenol, are discussed.

Yes-Associated Protein in Atherosclerosis and Related Complications: A Potential Therapeutic Target That Requires Further Exploration

Atherosclerosis and its complications diseases remain leading causes of cardiovascular morbidity and mortality, bringing a massive burden on public health worldwide. Atherosclerosis is recognized as chronic inflammation, and involves several highly correlated processes, including lipid metabolism dysfunction, endothelial cell dysfunction, inflammation, oxidative stress, vascular smooth muscle cell activation, platelet activation, thrombosis, altered matrix metabolism, and vascular remodeling. Within the past few decades, accumulating evidence has shown that the Yes-associated protein (YAP), the major effector of the Hippo pathway, can play a crucial role in pathogenesis and development of atherosclerosis. Activation of YAP-related pathways, which are induced by alerting flow pattern and matrix stiffness among others, can regulate processes including vascular endothelial cell dysfunction, monocyte infiltration, and smooth muscle cell migration, which contribute to atherosclerotic lesion formation. Further, YAP potentially modulates atherosclerotic complications such as vascular calcification and intraplaque hemorrhage, which require further investigation. Here, we summarized the relevant literature to outline current findings detailing the relationship between of YAP and atherosclerosis and highlight areas for future research.

Correlation between serum uric acid levels and carotid plaque neovascularisation assessed by contrast-enhanced ultrasound

AIM

To investigate the potential impact of serum uric acid (SUA) levels on the grade of intraplaque neovascularisation (IPN) at contrast-enhanced ultrasound (CEUS).

MATERIAL AND METHODS

The study screened 212 patients with carotid atherosclerotic plaques using conventional ultrasound, and the patients then underwent CEUS. Based on the distribution of contrast medium microbubbles in the plaque, patients were split into three groups: 60 patients regarded as grade 0-1 (group A), 81 patients as grade 2 (group B), and 71 patients as grade 3 (group C), and SUA levels were measured on the second day after CEUS.

RESULTS

The frequencies of stroke were statistically different between the three groups (p<0.05). In grades 0, 1, 2, and 3, SUA levels ranged from 236.92 ± 72.75, 276.46 ± 67.31, 283.93 ± 53.85, and 384.49 ± 79.80 μmol/l, respectively. Spearman's analysis showed that the visual grade of IPN at CEUS correlated linearly with the SUA level (r=0.551, p<0.01). The difference in SUA levels between different sexes was statistically significant (p<0.05), and the differences in plaque echogenicity and diastolic blood pressure (DBP) between the three groups were also statistically significant (all p<0.05).

CONCLUSIONS

SUA levels correlate positively with the visual grade of IPN at CEUS, which may promote plaque vulnerability. The present results may further help to optimise therapy for vulnerable plaque and improve stroke risk stratification strategies.

Bmal1 Downregulation Worsens Critical Limb Ischemia by Promoting Inflammation and Impairing Angiogenesis

Critical limb ischemia (CLI) is the most advanced clinical stage of peripheral vascular disease with high mobility and mortality. CLI patients suffer from lower extremity rest pain, ulceration, and gangrene caused by insufficient blood and oxygen supply. Seeking for effective biomarkers and therapeutic targets is of great significance for improving the life quality of CLI patients. The circadian clock has been reported to be involved in the progression of kinds of cardiovascular diseases. Whether and how circadian genes play a role in CLI remains unknown. In this study, by collecting femoral artery and muscle specimens of CLI patients who underwent amputation, we confirmed that the circadian gene Bmal1 is downregulated in the CLI femoral artery and ischemic distal lower limb muscle. Furthermore, we verified that Bmal1 affects CLI by regulating lipid metabolism, inflammation, and angiogenesis. A hindlimb ischemia model performed in wild-type and Bmal1^−/− mice confirmed that Bmal1 disruption would lead to impaired angiogenesis. In vitro experiments indicated that the decreased expression of Bmal1 would increase ox-LDL uptake and impair endothelial cell functions, including proliferation, migration, and tube formation. As for mechanisms, Bmal1 represses inflammation by inhibiting lipid uptake and by activating IL-10 transcription and promotes angiogenesis by transcriptionally regulating VEGF expression. In conclusion, we provide evidence that the circadian gene Bmal1 plays an important role in CLI by inhibiting inflammation and promoting angiogenesis. Thus, Bmal1 may be an effective biomarker and a potential therapeutic target in CLI.

PFKFB3 gene deletion in endothelial cells inhibits intraplaque angiogenesis and lesion formation in a murine model of venous bypass grafting

Vein grafting is a frequently used surgical intervention for cardiac revascularization. However, vein grafts display regions with intraplaque (IP) angiogenesis, which promotes atherogenesis and formation of unstable plaques. Graft neovessels are mainly composed of endothelial cells (ECs) that largely depend on glycolysis for migration and proliferation. In the present study, we aimed to investigate whether loss of the glycolytic flux enzyme phosphofructokinase-2/fructose-2,6-bisphosphatase 3 (PFKFB3) in ECs inhibits IP angiogenesis and as such prevents unstable plaque formation. To this end, apolipoprotein E deficient (ApoE^−/−) mice were backcrossed to a previously generated PFKFB3^fl/fl Cdh5^iCre mouse strain. Animals were injected with either corn oil (ApoE^−/−PFKFB3^fl/fl) or tamoxifen (ApoE^−/−PFKFB3^ECKO), and were fed a western-type diet for 4 weeks prior to vein grafting. Hereafter, mice received a western diet for an additional 28 days and were then sacrificed for graft assessment. Size and thickness of vein graft lesions decreased by 35 and 32%, respectively, in ApoE^−/−PFKFB3^ECKO mice compared to controls, while stenosis diminished by 23%. Moreover, vein graft lesions in ApoE^−/−PFKFB3^ECKO mice showed a significant reduction in macrophage infiltration (29%), number of neovessels (62%), and hemorrhages (86%). EC-specific PFKFB3 deletion did not show obvious adverse effects or changes in general metabolism. Interestingly, RT-PCR showed an increased M2 macrophage signature in vein grafts from ApoE^−/−PFKFB3^ECKO mice. Altogether, EC-specific PFKFB3 gene deletion leads to a significant reduction in lesion size, IP angiogenesis, and hemorrhagic complications in vein grafts. This study demonstrates that inhibition of endothelial glycolysis is a promising therapeutic strategy to slow down plaque progression.

Irisin in atherosclerosis

Irisin, a novel exercise-induced myokine, has been shown to play important roles in increasing white adipose tissue browning, regulating energy metabolism and improving insulin resistance. Growing evidence suggests a direct role for irisin in preventing atherosclerosis (AS) by inhibiting oxidative stress, improving dyslipidemia, facilitating anti-inflammation, reducing cellular damage and recovering endothelial function. In addition, some studies have noted that serum irisin levels play an essential role in cardiovascular diseases (CVDs) risk prediction, highlighting that irisin has the potential to be a useful predictive marker and therapeutic target of AS, especially in monitoring therapeutic efficacy. This review summarizes the understanding of irisin-mediated regulation in essential biological pathways and functions in atherosclerosis and prompts further exploitation of the biological properties of irisin in the pathogenesis of atherosclerosis.

ICAM-1-carrying targeted nano contrast agent for evaluating inflammatory injury in rabbits with atherosclerosis

To investigate the feasibility of using ICAM-1-targeted nano ultrasonic contrast to evaluate the degree of inflammatory injury at different stages in the abdominal aorta of rabbits with atherosclerosis (AS). Twenty-five experimental rabbits were assigned to five groups: the control group (A); the week-4 after modeling group (B); the week-8 after modeling group (C); the week-12 after modeling group (D); the week-16 after modeling group (E). All groups were given 2D ultrasonography, conventional ultrasonic contrast (SonoVue), and ICAM-1-targeted nano ultrasonic contrast, respectively. Signal intensity of vascular perfusion was evaluated. Signal intensity of ICAM-1-targeted nano ultrasonic contrast was substantially enhanced and prolonged in the vascular wall of the abdominal bubble aorta increased in B, C, D, and E groups (all P < 0.05). A positive linear correlation between intensity and the expression of ICAM-1 (r = 0.895, P < 0.001). The intensity of outer membrane was enhanced from week 4 to week 12, and both the intima-media membrane and outer membrane were enhanced with double-layer parallel echo at week 16, which was in line with the progression of atherosclerotic plaque inflammatory injury. ICAM-1-targeted nano contrast agent would be possibly a novel non-invasive molecular imaging method for plaque inflammatory injury and site high expression of specific adhesion molecules in early atherosclerotic lesions.

Inflammation and enhanced atherogenesis in the carotid artery with altered blood flow in an atherosclerosis-resistant mouse strain

Ligation of the common carotid artery near its bifurcation in apolipoprotein E-deficient (Apoe^-/- ) mice leads to rapid atherosclerosis development, which is affected by genetic backgrounds. BALB/cJ (BALB) mice are resistant to atherosclerosis, developing much smaller aortic lesions than C57BL/6 (B6) mice. In this study, we examined cellular events leading to lesion formation in carotid arteries with or without blood flow restriction of B6 and BALB Apoe^-/- mice. Blood flow was obstructed by ligating the left common carotid artery near its bifurcation in one group of mice, and other group received no surgical intervention. Without blood flow interruption, BALB-Apoe^-/- mice formed much smaller atherosclerotic lesions than B6-Apoe^-/- mice after 12 weeks of Western diet (3,325 ± 1,086 vs. 81,549 ± 9,983 µm² /section; p = 2.1E-7). Lesions occurred at arterial bifurcations in both strains. When blood flow was obstructed, ligated carotid artery of both strains showed notable lipid deposition, inflammatory cell infiltration, and rapid plaque formation. Neutrophils and macrophages were observed in the arterial wall of BALB mice 3 days after ligation and 1 week after ligation in B6 mice. CD4 T cells were observed in intimal lesions of BALB but not B6 mice. By 4 weeks, both strains developed similar sizes of advanced lesions containing foam cells, smooth muscle cells, and neovessels. Atherosclerosis also occurred in straight regions of the contralateral common carotid artery where MCP-1 was abundantly expressed in the intima of BALB mice. These findings indicate that the disturbed blood flow is more prominent than high fat diet in promoting inflammation and atherosclerosis in hyperlipidemic BALB mice.

Dilated microvessel with endothelial cell proliferation involves intraplaque hemorrhage in unstable carotid plaque

BACKGROUND

The purpose of the present study was to clarify the characteristics of endothelial cell (EC) proliferation in intraplaque microvessels in vulnerable plaques and impact on clinical results.

METHODS

The present study included 76 patients who underwent carotid endarterectomy. Patients were classified into three groups based on their symptoms: asymptomatic, symptomatic without recurrent ischemic event, and symptomatic with recurrent ischemic event. MR plaque imaging was performed and surgical specimens underwent immunohistochemical analysis. The number of CD31⁺ microvessels, and Ki67⁺ and CD105⁺ ECs in the carotid plaques was quantified, as measurements of maximum CD31⁺ microvessel diameter.

RESULTS

MR plaque imaging yielded 41 subjects (54.0%) diagnosed with plaque with intraplaque hemorrhage (IPH), 14 subjects (18.4%) diagnosed with fibrous plaques, and 21 (27.6%) subjects diagnosed with lipid-rich plaques. The average largest diameter of microvessel in fibrous plaques, lipid-rich plaques, and plaque with IPH was 12.7 ± 4.1 μm, 31.3 ± 9.3 μm, and 56.4 ± 10.0 μm, respectively (p < 0.01). Dilated microvessels (>40 μm) were observed in 9.6% of plaques with IPH but only in 2.8% of lipid-rich plaques and 0% of fibrous plaques (p < 0.01). Ki67⁺/CD31⁺ ECs were identified in 2.8 ± 1.2% of fibrous plaques, 9.6 ± 6.9% of lipid-rich plaques, and in 19.5 ± 5.9% of plaques with IPH (p < 0.01). The average largest diameter of microvessels in the asymptomatic group was 17.1 ± 8.7 μm, 32.3 ± 10.8 μm in the symptomatic without recurrence group, and 55.2 ± 13.2 μm in the symptomatic with recurrence group (p < 0.01).

CONCLUSION

Dilated microvessels with proliferative ECs may play a key role in IPH pathogenesis. Furthermore, dilated microvessels are likely related to clinical onset and the recurrence of ischemic events. The purpose of the present study was to clarify the characteristics of EC proliferation in intraplaque microvessels in vulnerable plaques and their impact on clinical results, focusing on dilated intraplaque microvessels.

Endoglin/CD105-Based Imaging of Cancer and Cardiovascular Diseases: A Systematic Review

Molecular imaging of pathologic lesions can improve efficient detection of cancer and cardiovascular diseases. A shared pathophysiological feature is angiogenesis, the formation of new blood vessels. Endoglin (CD105) is a coreceptor for ligands of the Transforming Growth Factor-β (TGF-β) family and is highly expressed on angiogenic endothelial cells. Therefore, endoglin-based imaging has been explored to visualize lesions of the aforementioned diseases. This systematic review highlights the progress in endoglin-based imaging of cancer, atherosclerosis, myocardial infarction, and aortic aneurysm, focusing on positron emission tomography (PET), single-photon emission computed tomography (SPECT), magnetic resonance imaging (MRI), near-infrared fluorescence (NIRF) imaging, and ultrasound imaging. PubMed was searched combining the following subjects and their respective synonyms or relevant subterms: "Endoglin", "Imaging/Image-guided surgery". In total, 59 papers were found eligible to be included: 58 reporting about preclinical animal or in vitro models and one ex vivo study in human organs. In addition to exact data extraction of imaging modality type, tumor or cardiovascular disease model, and tracer (class), outcomes were described via a narrative synthesis. Collectively, the data identify endoglin as a suitable target for intraoperative and diagnostic imaging of the neovasculature in tumors, whereas for cardiovascular diseases, the evidence remains scarce but promising.

Efficacy of the Piperidine Nitroxide 4-MethoxyTEMPO in Ameliorating Serum Amyloid A-Mediated Vascular Inflammation

Intracellular redox imbalance in endothelial cells (EC) can lead to endothelial dysfunction, which underpins cardiovascular diseases (CVD). The acute phase serum amyloid A (SAA) elicits inflammation through stimulating production of reactive oxygen species (ROS). The cyclic nitroxide 4-MethoxyTEMPO (4-MetT) is a superoxide dismutase mimetic that suppresses oxidant formation and inflammation. The aim of this study was to investigate whether 4-MetT inhibits SAA-mediated activation of cultured primary human aortic EC (HAEC). Co-incubating cells with 4-MetT inhibited SAA-mediated increases in adhesion molecules (VCAM-1, ICAM-1, E-selectin, and JAM-C). Pre-treatment of cells with 4-MetT mitigated SAA-mediated increases in transcriptionally activated NF-κB-p65 and P120 Catenin (a stabilizer of Cadherin expression). Mitochondrial respiration and ROS generation (mtROS) were adversely affected by SAA with decreased respiratory reserve capacity, elevated maximal respiration and proton leakage all characteristic of SAA-treated HAEC. This altered respiration manifested as a loss of mitochondrial membrane potential (confirmed by a decrease in TMRM fluorescence), and increased mtROS production as assessed with MitoSox Red. These SAA-linked impacts on mitochondria were mitigated by 4-MetT resulting in restoration of HAEC nitric oxide bioavailability as confirmed by assessing cyclic guanosine monophosphate (cGMP) levels. Thus, 4-MetT ameliorates SAA-mediated endothelial dysfunction through normalising EC redox homeostasis. Subject to further validation in in vivo settings; these outcomes suggest its potential as a therapeutic in the setting of cardiovascular pathologies where elevated SAA and endothelial dysfunction is linked to enhanced CVD.

In vitro angiogenesis inhibition with selective compounds targeting the key glycolytic enzyme PFKFB3

Abnormal glycolytic metabolism contributes to angiogenic sprouting involved in atherogenesis. We investigated the potential anti-angiogenic properties of specific 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3 (PFKFB3) inhibitors in endothelial cells (ECs). ECs were treated with PFKFB3 inhibitors (named PA-1 and PA-2) and their effects on metabolic and functional characteristics of ECs were investigated. The anti-glycolytic compound 3-(pyridinyl)- 1-(4-pyridinyl)- 2-propen-1-one (3PO) was used as reference compound. PFKFB3 expression and activity (IC₅₀ about 3-21 nM) was inhibited upon treatment with both compounds. Glucose uptake and lactate export were measured using commercial assays and showed a partial reduction up to 40%. PFKFB3 inhibition increased intracellular lactate accumulation, and reduced expression of monocarboxylate transporters-1 (MCT1) and MCT4. Furthermore, endothelial cell migration and proliferation assays demonstrated significant reduction upon treatment with both compounds. Matrix- metalloproteinase (MMP) activity, measured by gelatin zymography, and expression was significantly reduced (up to 25%). In addition, PA compounds downregulated the expression of VCAM-1, VE-cadherin, VEGFa, VEGFR2, TGF-β, and IL-1β, in inflamed ECs. Finally, PA-1 and PA-2 treatment impaired the formation of angiogenic sprouts measured by both morphogenesis and spheroid-based angiogenesis assays. Our data demonstrate that the anti-glycolytic PA compounds may affect several steps involved in angiogenesis. Targeting the key glycolytic enzyme PFKFB3 might represent an attractive therapeutic strategy to improve the efficacy of cancer treatments, or to be applied in other pathologies where angiogenesis is a detrimental factor.

Endothelial Barrier Function and Leukocyte Transmigration in Atherosclerosis

The vascular endothelium is a highly specialized barrier that controls passage of fluids and migration of cells from the lumen into the vessel wall. Endothelial cells assist leukocytes to extravasate and despite the variety in the specific mechanisms utilized by different leukocytes to cross different vascular beds, there is a general principle of capture, rolling, slow rolling, arrest, crawling, and ultimately diapedesis via a paracellular or transcellular route. In atherosclerosis, the barrier function of the endothelium is impaired leading to uncontrolled leukocyte extravasation and vascular leakage. This is also observed in the neovessels that grow into the atherosclerotic plaque leading to intraplaque hemorrhage and plaque destabilization. This review focuses on the vascular endothelial barrier function and the interaction between endothelial cells and leukocytes during transmigration. We will discuss the role of endothelial dysfunction, transendothelial migration of leukocytes and plaque angiogenesis in atherosclerosis.

Clinical Efficacy and Safety of Angiogenesis Inhibitors: Sex Differences and Current Challenges

Vasoactive molecules, such as vascular endothelial growth factor (VEGF) and endothelins, share cytokine-like activities and regulate endothelial cell (EC) growth, migration and inflammation. Some endothelial mediators and their receptors are targets for currently approved angiogenesis inhibitors, drugs that are either monoclonal antibodies raised towards VEGF, or inhibitors of vascular receptor protein kinases and signaling pathways. Pharmacological interference with the protective functions of ECs results in a similar spectrum of adverse effects. Clinically, the most common side effects of VEGF signaling pathway inhibition include an increase in arterial pressure, left ventricular (LV) dysfunction ultimately causing heart failure, and thromboembolic events, including pulmonary embolism, stroke, and myocardial infarction. Sex steroids such as androgens, progestins, and estrogen and their receptors (ERα, ERβ, GPER; PR-A, PR-B; AR) have been identified as important modifiers of angiogenesis, and sex differences have been reported for anti-angiogenic drugs. This review article discusses the current challenges clinicians are facing with regard to angiogenesis inhibitor treatments, including the need to consider sex differences affecting clinical efficacy and safety. We also propose areas for future research taking into account the role of sex hormone receptors and sex chromosomes. Development of new sex-specific drugs with improved target and cell-type selectivity likely will open the way personalized medicine in men and women requiring antiangiogenic therapy and result in reduced adverse effects and improved therapeutic efficacy.

Assessment of Microvessel Permeability in Murine Atherosclerotic Vein Grafts Using Two-Photon Intravital Microscopy

Plaque angiogenesis and plaque hemorrhage are major players in the destabilization and rupture of atherosclerotic lesions. As these are dynamic processes, imaging of plaque angiogenesis, especially the integrity or leakiness of angiogenic vessels, can be an extremely useful tool in the studies on atherosclerosis pathophysiology. Visualizing plaque microvessels in 3D would enable us to study the architecture and permeability of adventitial and intimal plaque microvessels in advanced atherosclerotic lesions. We hypothesized that a comparison of the vascular permeability between healthy continuous and fenestrated as well as diseased leaky microvessels, would allow us to evaluate plaque microvessel leakiness. We developed and validated a two photon intravital microscopy (2P-IVM) method to assess the leakiness of plaque microvessels in murine atherosclerosis-prone ApoE3*Leiden vein grafts based on the quantification of fluorescent-dextrans extravasation in real-time. We describe a novel 2P-IVM set up to study vessels in the neck region of living mice. We show that microvessels in vein graft lesions are in their pathological state more permeable in comparison with healthy continuous and fenestrated microvessels. This 2P-IVM method is a promising approach to assess plaque angiogenesis and leakiness. Moreover, this method is an important advancement to validate therapeutic angiogenic interventions in preclinical atherosclerosis models.

Periprocedural Hydrogen Sulfide Therapy Improves Vascular Remodeling and Attenuates Vein Graft Disease

Background Failure rates after revascularization surgery remain high, both in vein grafts (VG) and arterial interventions. One promising approach to improve outcomes is endogenous upregulation of the gaseous transmitter-molecule hydrogen sulfide, via short-term dietary restriction. However, strict patient compliance stands as a potential translational barrier in the vascular surgery patient population. Here we present a new therapeutic approach, via a locally applicable gel containing the hydrogen sulfide releasing prodrug (GYY), to both mitigate graft failure and improve arterial remodeling. Methods and Results All experiments were performed on C57BL/6 (male, 12 weeks old) mice. VG surgery was performed by grafting a donor-mouse cava vein into the right common carotid artery of a recipient via an end-to-end anastomosis. In separate experiments arterial intimal hyperplasia was assayed via a right common carotid artery focal stenosis model. All mice were harvested at postoperative day 28 and artery/graft was processed for histology. Efficacy of hydrogen sulfide was first tested via GYY supplementation of drinking water either 1 week before VG surgery (pre-GYY) or starting immediately postoperatively (post-GYY). Pre-GYY mice had a 36.5% decrease in intimal/media+adventitia area ratio compared with controls. GYY in a 40% Pluronic gel (or vehicle) locally applied to the graft/artery had decreased intimal/media area ratios (right common carotid artery) and improved vessel diameters. GYY-geltreated VG had larger diameters at both postoperative days 14 and 28, and a 56.7% reduction in intimal/media+adventitia area ratios. Intimal vascular smooth muscle cell migration was decreased 30.6% after GYY gel treatment, which was reproduced in vitro. Conclusions Local gel-based treatment with the hydrogen sulfide-donor GYY stands as a translatable therapy to improve VG durability and arterial remodeling after injury.

Activating CD137 Signaling Promotes Sprouting Angiogenesis via Increased VEGFA Secretion and the VEGFR2/Akt/eNOS Pathway

Combination of antiangiogenesis and immunotherapy may be an effective strategy for treatment of solid tumors. Our previous work reported that activation of CD137 signaling promotes intraplaque angiogenesis. A number of studies have demonstrated that vascular endothelial growth factor receptor 2 (VEGFR2) is a key target for angiogenesis. However, it is unknown whether CD137-mediated angiogenesis is related to VEGFR2. In this study, we investigated the effect of CD137 on the VEGFR2 expression and explored the underlying mechanisms of CD137-mediated angiogenesis. Knock-out of CD137 in ApoE^−/− mice significantly decreased neovessel density in atherosclerotic plaques. CD137 silencing or inhibition attenuated endothelial cell (ECs) proliferation, migration, and tube formation. We found activation of CD137 signaling for increased VEGFR2 transcription and translation steadily. Moreover, CD137 signaling activated phosphorylated VEGFR2 (Tyr1175) and the downstream Akt/eNOS pathway, whereas neutralizing CD137 signaling weakened the activation of VEGFR2 and the downstream Akt/eNOS pathway. The aortic ring assay further demonstrated that CD137 signaling promoted ECc sprouting. Inhibition of VEGFR2 by siRNA or XL184 (cabozantinib) and inhibition of downstream signaling by LY294002 (inhibits AKT activation) and L-NAME (eNOS inhibitor) remarkably abolished proangiogenic effects of CD137 signaling both in vitro and ex vivo. In addition, the condition medium from CD137-activated ECs and vascular endothelial growth factor A (VEGFA) had similar effects on ECs that expressed high VEGFR2. Additionally, activating CD137 signaling promoted endothelial secretion of VEGFA, while blocking CD137 signaling attenuated VEGFA secretion. In conclusion, activation of CD137 signaling promoted sprouting angiogenesis by increased VEGFA secretion and the VEGFR2/Akt/eNOS pathway. These findings provide a basis for stabilizing intraplaque angiogenesis through VEGFR2 intervatioin, as well as cancer treatment via combination of CD137 agonists and specific VEGFR2 inhibitors.

Ultrastructural Pathology of Atherosclerosis, Calcific Aortic Valve Disease, and Bioprosthetic Heart Valve Degeneration: Commonalities and Differences

Atherosclerosis, calcific aortic valve disease (CAVD), and bioprosthetic heart valve degeneration (alternatively termed structural valve deterioration, SVD) represent three diseases affecting distinct components of the circulatory system and their substitutes, yet sharing multiple risk factors and commonly leading to the extraskeletal calcification. Whereas the histopathology of the mentioned disorders is well-described, their ultrastructural pathology is largely obscure due to the lack of appropriate investigation techniques. Employing an original method for sample preparation and the electron microscopy visualisation of calcified cardiovascular tissues, here we revisited the ultrastructural features of lipid retention, macrophage infiltration, intraplaque/intraleaflet haemorrhage, and calcification which are common or unique for the indicated types of cardiovascular disease. Atherosclerotic plaques were notable for the massive accumulation of lipids in the extracellular matrix (ECM), abundant macrophage content, and pronounced neovascularisation associated with blood leakage and calcium deposition. In contrast, CAVD and SVD generally did not require vasculo- or angiogenesis to occur, instead relying on fatigue-induced ECM degradation and the concurrent migration of immune cells. Unlike native tissues, bioprosthetic heart valves contained numerous specialised macrophages and were not capable of the regeneration that underscores ECM integrity as a pivotal factor for SVD prevention. While atherosclerosis, CAVD, and SVD show similar pathogenesis patterns, these disorders demonstrate considerable ultrastructural differences.

Three-Dimensional Imaging of Intraplaque Neovascularization in a Mouse Model of Advanced Atherosclerosis

Multiple lines of evidence suggest that intraplaque (IP) neovascularization promotes atherosclerotic plaque growth, destabilization, and rupture. However, pharmacological inhibition of IP neovascularization remains largely unexplored due to the limited number of animal models that develop IP neovessels and the lack of reliable methods for visualizing IP angiogenesis. Here, we applied 3D confocal microscopy with an optimized tissue-clearing process, immunolabeling-enabled three-dimensional imaging of solvent-cleared organs, to visualize IP neovessels in apolipoprotein E-deficient (ApoE-/-) mice carrying a heterozygous mutation (C1039+/-) in the fibrillin-1 gene. Unlike regular ApoE-/- mice, this mouse model is characterized by the presence of advanced plaques with evident IP neovascularization. Plaques were stained with antibodies against endothelial marker CD31 for 3 days, followed by incubation with fluorescently labeled secondary antibodies. Subsequent tissue clearing with dichloromethane (DCM)/methanol, DCM, and dibenzyl ether allowed easy visualization and 3D reconstruction of the IP vascular network while plaque morphology remained intact.

Circulating CX3CR1+CD163+ M2 monocytes markedly elevated and correlated with cardiac markers in patients with acute myocardial infarction

Background

Vulnerable plaques have been generally recognized to play a role in the pathogenesis of acute myocardial infarction (AMI), however, the role of circulating CX3CR1⁺CD163⁺ M2 monocytes has not been studied properly. We aim to evaluate the features of CX3CR1⁺CD163⁺ M2 monocytes and its relationship with cardiac specific markers in AMI patients.

Methods

The circulating M2 monocytes were identified in AMI patients (n=35) and healthy controls (HCs, n=10) by flow cytometry using two staining methods: CD68⁺CD163⁺ (cytoplasmic staining) and CX3CR1⁺CD163⁺ (surface staining). CX3CR1⁺ monocytes were purified by magnetic cell sorting. The expression level of peroxisome proliferator-activated receptor γ (PPARγ) and arginase-1 (Arg-1) were measured by real-time quantitative PCR and Western Blot in CX3CR1⁺ monocytes.

Results

Circulating M2 monocytes extremely expanded in AMI patients compared with HCs (P<0.01). Positive linear correlation was confirmed between CD68⁺CD163⁺ and CX3CR1⁺CD163⁺ cell populations in AMI patients (r=0.39, P=0.02). The percentage of circulating CX3CR1⁺CD163⁺ M2 monocytes positively correlated with cardiac specific markers (cTNT, CK-MB) and acute phase markers (glucose, hs-CRP) (cTNT, r=0.63, P<0.01, CK-MB, r=0.54, P<0.01, glucose, r=0.62, P<0.01, hs-CRP, r=0.58, P<0.01). CX3CR1⁺ monocytes in AMI patients expressed higher levels of PPARγ and Arg-1 than those in HCs (P<0.01).

Conclusions

Circulating M2 monocytes increased in AMI patients and positively correlated with the elevation of both cardiac specific and acute phase markers. CX3CR1⁺CD163⁺ M2 monocytes might have application value for the early diagnosis of AMI.

Partial Inhibition of Glycolysis Reduces Atherogenesis Independent of Intraplaque Neovascularization in Mice

OBJECTIVE

Intraplaque neovascularization is an important feature of unstable human atherosclerotic plaques. However, its impact on plaque formation and stability is poorly studied. Because proliferating endothelial cells generate up to 85% of their ATP from glycolysis, we investigated whether pharmacological inhibition of glycolytic flux by the small-molecule 3PO (3-[3-pyridinyl]-1-[4-pyridinyl]-2-propen-1-one) could have beneficial effects on plaque formation and composition. Approach and Results: ApoE-/- (apolipoprotein E deficient) mice treated with 3PO (50 µg/g, ip; 4×/wk, 4 weeks) showed a metabolic switch toward ketone body formation. Treatment of ApoE-/-Fbn1C1039G+/- mice with 3PO (50 µg/g, ip) either after 4 (preventive, twice/wk, 10 weeks) or 16 weeks of Western diet (curative, 4×/wk, 4 weeks) inhibited intraplaque neovascularization by 50% and 38%, respectively. Plaque formation was significantly reduced in all 3PO-treated animals. This effect was independent of intraplaque neovascularization. In vitro experiments showed that 3PO favors an anti-inflammatory M2 macrophage subtype and suppresses an M1 proinflammatory phenotype. Moreover, 3PO induced autophagy, which in turn impaired NF-κB (nuclear factor-kappa B) signaling and inhibited TNF-α (tumor necrosis factor-alpha)-mediated VCAM-1 (vascular cell adhesion molecule-1) and ICAM-1 (intercellular adhesion molecule-1) upregulation. Consistently, a preventive 3PO regimen reduced endothelial VCAM-1 expression in vivo. Furthermore, 3PO improved cardiac function in ApoE-/-Fbn1C1039G+/- mice after 10 weeks of treatment.

CONCLUSIONS

Partial inhibition of glycolysis restrained intraplaque angiogenesis without affecting plaque composition. However, less plaques were formed, which was accompanied by downregulation of endothelial adhesion molecules-an event that depends on autophagy induction. Inhibition of coronary plaque formation by 3PO resulted in an overall improved cardiac function.