Immune-mediated mechanisms of atherosclerosis and implications for the clinic

Targeting gut microbiota to regulate the adaptive immune response in atherosclerosis

Atherosclerosis, the leading cause of death worldwide, is a chronic inflammatory disease leading to the accumulation of lipid-rich plaques in the intima of large and medium-sized arteries. Accumulating evidence indicates the important regulatory role of the adaptive immune system in atherosclerosis during all stages of the disease. The gut microbiome has also become a key regulator of atherosclerosis and immunomodulation. Whilst existing research extensively explores the impact of the microbiome on the innate immune system, only a handful of studies have explored the regulatory capacity of the microbiome on the adaptive immune system to modulate atherogenesis. Building on these concepts and the pitfalls on the gut microbiota and adaptive immune response interaction, this review explores potential strategies to therapeutically target the microbiome, including the use of prebiotics and vaccinations, which could influence the adaptive immune response and consequently plaque composition and development.

Immunologic and inflammatory pathogenesis of chronic coronary syndromes: A review

Chronic coronary syndrome (CCS) is a major cause of progression to acute coronary syndrome. Due to its insidious onset and complex etiology, this condition is often underestimated and insufficiently recognized, and traditional interventions for risk factors do not effectively control the disease progression. Current research suggests that immune and inflammatory pathways contribute to atherosclerosis and its clinical complications, thereby triggering the progression of CCS to acute coronary syndrome. This article primarily reviews the possible mechanisms of immune and inflammatory responses in CCS, with the aim of providing references for the diagnosis, treatment, and prevention of CCS.

White matter disease derived from vascular and demyelinating origins

Damage or microstructural alterations of the white matter can cause dysfunction of the intrinsic neural networks in a condition termed as white matter disease (WMD). Frequently detected on brain computed tomography and magnetic resonance imaging scans, WMD is commonly presented in inflammatory demyelinating diseases like multiple sclerosis (MS) and vascular diseases such as cerebral small vessel disease (CSVD). Prevention of MS and CSVD progression requires early treatments with drastically different medications and approaches, as such, early and accurate diagnosis of WMD, derived from vascular or demyelinating etiologies, is of paramount importance. However, the clinical and imaging similarities between MS, especially during the early stage, and CSVD, pose a significant dilemma in differentiating these two conditions. In this review, we attempt to summarize and contrast the distinguishing features of MS and CSVD for aiding accurate diagnosis to ensure timely corresponding management in the early stages of MS and CSVD.

Cellular metabolism changes in atherosclerosis and the impact of comorbidities

Cell activation and nutrient dysregulation are common consequences of atherosclerosis and its preceding risk factors, such as hypertension, dyslipidemia, and diabetes. These diseases may also impact cellular metabolism and consequently cell function, and the other way around, altered cellular metabolism can impact disease development and progression through altered cell function. Understanding the contribution of altered cellular metabolism to atherosclerosis and how cellular metabolism may be altered by co-morbidities and atherosclerosis risk factors could support the development of novel strategies to lower the risk of CVD. Therefore, we briefly review disease pathogenesis and the principles of cell metabolic pathways, before detailing changes in cellular metabolism in the context of atherosclerosis and comorbidities. In the hypoxic, inflammatory and hyperlipidemic milieu of the atherosclerotic plaque riddled with oxidative stress, metabolism shifts to increase anaerobic glycolysis, the pentose-phosphate pathway and amino acid use. We elaborate on metabolic changes for macrophages, neutrophils, vascular endothelial cells, vascular smooth muscle cells and lymphocytes in the context of atherosclerosis and its co-morbidities hypertension, dyslipidemia, and diabetes. Since causal relationships of specific key genes in a metabolic pathway can be cell type-specific and comorbidity-dependent, the impact of cell-specific metabolic changes must be thoroughly explored in vivo, with a focus on also systemic effects. When cell-specific treatments become feasible, this information will be crucial for determining the best metabolic intervention to improve atherosclerosis and its interplay with co-morbidities.

Inflammation in HIV and Its Impact on Atherosclerotic Cardiovascular Disease

People living with HIV have a 1.5- to 2-fold increased risk of developing cardiovascular disease. Despite treatment with highly effective antiretroviral therapy, people living with HIV have chronic inflammation that makes them susceptible to multiple comorbidities. Several factors, including the HIV reservoir, coinfections, clonal hematopoiesis of indeterminate potential (CHIP), microbial translocation, and antiretroviral therapy, may contribute to the chronic state of inflammation. Within the innate immune system, macrophages harbor latent HIV and are among the prominent immune cells present in atheroma during the progression of atherosclerosis. They secrete inflammatory cytokines such as IL (interleukin)-6 and tumor necrosis-α that stimulate the expression of adhesion molecules on the endothelium. This leads to the recruitment of other immune cells, including cluster of differentiation (CD)8+ and CD4+ T cells, also present in early and late atheroma. As such, cells of the innate and adaptive immune systems contribute to both systemic inflammation and vascular inflammation. On a molecular level, HIV-1 primes the NLRP3 (NLR family pyrin domain containing 3) inflammasome, leading to an increased expression of IL-1β, which is important for cardiovascular outcomes. Moreover, activation of TLRs (toll-like receptors) by HIV, gut microbes, and substance abuse further activates the NLRP3 inflammasome pathway. Finally, HIV proteins such as Nef (negative regulatory factor) can inhibit cholesterol efflux in monocytes and macrophages through direct action on the cholesterol transporter ABCA1 (ATP-binding cassette transporter A1), which promotes the formation of foam cells and the progression of atherosclerotic plaque. Here, we summarize the stages of atherosclerosis in the context of HIV, highlighting the effects of HIV, coinfections, and antiretroviral therapy on cells of the innate and adaptive immune system and describe current and future interventions to reduce residual inflammation and improve cardiovascular outcomes among people living with HIV.

Pathogenetic mechanisms of repeated adverse cardiovascular events development in patients with coronary heart disease: the role of chronic inflammation

Stent restenosis is the most unfavorable complication of interventional treatment for coronary heart disease. We already know from various literature sources that the causes for stent restenosis in patients are both mechanical damage (partial opening, stent breakage, extended stented area, calcification, incomplete stent coverage of atherosclerotic plaque, weak radial stiffness of the stent metal frame, lack of stent drug coating), and the neointimal hyperplasia formation which is closely related to the de novo atherosclerosis development, being a predictor of the recurrent cardiovascular event.

Biomimetic nanoparticles targeting atherosclerosis for diagnosis and therapy

Atherosclerosis is a typical chronic inflammatory vascular disease that seriously endangers human health. At present, oral lipid-lowering or anti-inflammatory drugs are clinically used to inhibit the development of atherosclerosis. However, traditional oral drug treatments have problems such as low utilization, slow response, and serious side effects. Traditional nanodrug delivery systems are difficult to interactively recognize by normal biological organisms, and it is difficult to target the delivery of drugs to target lesions. Therefore, building a biomimetic nanodrug delivery system with targeted drug delivery based on the pathological characteristics of atherosclerosis is the key to achieving efficient and safe treatment of atherosclerosis. In this review, various nanodrug delivery systems that can target atherosclerosis are summarized and discussed. In addition, the future prospects and challenges of its clinical translation are also discussed.

Endothelial exosomes work as a functional mediator to activate macrophages

Introduction

Intercellular communication is essential for almost all physiological and pathological processes. Endothelial cell (EC)-derived exosomes, working as mediators for intercellular information exchange, are involved in the pathophysiological mechanisms of atherosclerosis. However, the effect of inflamed endothelial exosomes on the function of macrophages (Mϕ) is poorly defined. This study aims to unravel how exosomes derived from tumor necrosis factor-α (TNF-α)-stimulated ECs (exo-T) affect Mϕ in vitro.

Methods and results

Exosomes derived from untreated ECs (exo) and exo-T were identified by using TEM, NTA, and western blot, and we observed that PKH67-labeled exo/exo-T were taken up by Mϕ. Exposure to exo-T for 24 h not only skewed Mϕ to the M1 subtype and exacerbated lipid deposition, but also promoted Mϕ apoptosis, while it did not significantly affect Mϕ migration, as detected by RT-qPCR, Dil-ox-LDL uptake assay, flow cytometry, wound healing assay, and transwell assay, respectively. In addition, exo/exo-T-related microRNA-Seq revealed 104 significantly differentially expressed microRNAs (DE-miRNAs). The target genes of DE-miRNAs were mainly enriched functionally in metabolic pathways, MAPK signaling pathway, etc., as determined using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. We further demonstrated by immunoblotting that exo-T intervention improves the phosphorylation of MAPK/NF-κB-related proteins.

Discussion and conclusion

Collectively, this study reveals that inflamed endothelial exosomes (TNF-α-stimulated EC-derived exosomes) work as a functional mediator to affect Mϕ function and may activate Mϕ through MAPK/NF-κB signaling pathways.

Potential Application of the Plant-Derived Essential Oils for Atherosclerosis Treatment: Molecular Mechanisms and Therapeutic Potential

Essential oils (EOs) are complex secondary metabolites identified in many plant species. Plant-derived EOs have been widely used in traditional medicine for centuries for their health-beneficial effects. Some EOs and their active ingredients have been reported to improve the cardiovascular system, in particular to provide an anti-atherosclerotic effect. The objective of this review is to highlight the recent research investigating the anti-inflammatory, anti-oxidative and lipid-lowering properties of plant-derived EOs and discuss their mechanisms of action. Also, recent clinical trials exploring anti-inflammatory and anti-oxidative activities of EOs are discussed. Future research on EOs has the potential to identify new bioactive compounds and invent new effective agents for treatment of atherosclerosis and related diseases such as diabetes, metabolic syndrome and obesity.

Biologics for Reducing Cardiovascular Risk in Psoriasis Patients

Psoriasis is a chronic inflammatory skin disease with a high prevalence of cardiovascular disease (CVD), obesity, dyslipidemia, hypertension, diabetes mellitus, and metabolic syndrome. Among them, CVD is the most common cause of morbidity and mortality in psoriasis patients. Since CVD is associated with considerable morbidity and mortality, primary care clinicians are increasingly committed to reducing the risk of CVD in patients with psoriasis. Biologics targeting TNF-α, IL-12/23, and IL-17 are systemic therapies that can dramatically improve the condition of psoriasis. Recent studies have reported that these inflammatory cytokine signals may promote atherosclerosis, suggesting that biologics might be effective for improving psoriasis as well as reducing the risk of CVD. Here, we reviewed cardiovascular risk in psoriasis patients, the association between psoriatic inflammation and atherosclerosis, and the efficacy of biologics for reducing the risk of cardiovascular diseases.

The Vascular System: Anatomical, Physiological, Pathological, and Aging Considerations

The vascular system is one of the earliest recognized anatomical systems. It is composed of 3 parts; arterial, capillary, and venous, each with their own unique anatomy and physiology. Blood flow through this system is compromised in aging, atherosclerosis and peripheral vascular disease, and the practicing anesthesiologist must understand both the physiology and pathophysiology of the vascular tree.

Dyslipidemia in Transplant Patients: Which Therapy?

Cardiovascular disease is the most important cause of death worldwide in recent years; an increasing trend is also shown in organ transplant patients subjected to immunosuppressive therapies, in which cardiovascular diseases represent one of the most frequent causes of long-term mortality. This is also linked to immunosuppressant-induced dyslipidemia, which occurs in 27 to 71% of organ transplant recipients. The aim of this review is to clarify the pathophysiological mechanisms underlying dyslipidemia in patients treated with immunosuppressants to identify immunosuppressive therapies which do not cause dyslipidemia or therapeutic pathways effective in reducing hypercholesterolemia, hypertriglyceridemia, or both, without further adverse events.

Current and emerging drugs for the treatment of atherosclerosis: the evidence to date

INTRODUCTION

Atherosclerosis can be considered a chronic inflammatory process that stands out as a dominant cause of cardiovascular disease (CVD). Since blood lipids are the leading risk factor for atherosclerosis development, lowering low-density lipoprotein cholesterol (LDL-C) and other apolipoprotein B-containing lipoproteins reduces the risk of future cardiovascular events. However, there has been significant progress in developing lipid-lowering drugs for aggressive management of dyslipidemia, the rates of CVD events remain unacceptably high, so there is great need to identify novel therapeutic pathways targeting the atherosclerosis process.

AREAS COVERED

We discussed the current guidelines on CVD prevention, the role of novel lipid-lowering drugs, as well as emerging drugs for atherosclerosis, emphasizing the current data on compounds targeting inflammatory and oxidant pathways.

EXPERT OPINION

Although novel lipid-lowering drugs all showed their therapeutic efficacy in LDL-C lowering, data regarding their impact on cardiovascular outcomes is still inconclusive. On the other hand, some of the agents targeting inflammatory pathways, especially colchicine, showed promising results in terms of reducing CVD events. In contrast, those pointed at oxidant pathways failed to do so. Finally, exploring ways of targeting new therapeutic venues, such as adaptive immunity and clonal hematopoiesis, is a goal in the future.

A Associação de TWEAK com Calcificação da Artéria Coronária em Pacientes com Doença Renal Crônica

Fundamento

O receptor fraco indutor de apoptose semelhante a fator de necrose tumoral solúvel (sTWEAK) é um membro da superfamília de TNF que tem um papel crítico na proliferação e inflamação na circulação arterial.

Objetivos

Este estudo prospectivo tem o objetivo de mostrar a relação entre os níveis de sTWEAK e calcificação da artéria coronária (CAC) em pacientes com doença renal crônica (DRC).

Métodos

Este estudo prospectivo incluiu 139 pacientes consecutivos que passaram por angiografia coronariana por tomografia computadorizada, por qualquer motivo, para síndromes coronarianas agudas, de agosto de 2020 a fevereiro de 2021. Um total de 12 pacientes foi excluído do estudo devido aos critérios de exclusão. Os pacientes foram divididos em dois grupos com base em terem um escore CAC menor que 400 (n=84) ou um escore de 400 ou mais (n=43). A significância foi presumida em p-valor bilateral <0,05.

Resultados

À medida que o escore CAC aumentou, os níveis de sTWEAK diminuíram de forma estatisticamente significativa e detectou-se uma relação forte entre níveis de sTWEAK e escore CAC (r: -0,779, p<0,001). A análise ROC revelou que o nível de corte ideal de sTWEAK para prever o escore CAC de 400 era 761 pg/mL com uma sensibilidade de 71% e especificidade de 73% (AUC: 0,78; IC 95%: 0,70-0,85; p <0,001).

Conclusões

Embora os estudos em larga escala tenham demonstrado uma correlação positiva entre os níveis de TFGe e sTWEAK, alguns estudos detectaram que o aumento nos níveis de sTWEAK estão associados a mortalidade e gravidade do sistema da artéria coronária em pacientes com DRC. Nossos resultados comprovam nossa hipótese de que os níveis de sTWEAK mostram calcificação coronária em vez de outros tipos de placas ateroscleróticas.

Effects of Green Tea (-)-Epigallocatechin-3-Gallate (EGCG) on Cardiac Function - A Review of the Therapeutic Mechanism and Potentials

Heart disease, the leading cause of death globally, refers to various illnesses that affect heart structure and function. Specific abnormalities affecting cardiac muscle contractility and remodeling and common factors including oxidative stress, inflammation, and apoptosis underlie the pathogenesis of heart diseases. Epidemiology studies have associated green tea consumption with lower morbidity and mortality of cardiovascular diseases, including heart and blood vessel dysfunction. Among the various compounds found in green tea, catechins are believed to play a significant role in producing benefits to cardiovascular health. Comprehensive literature reviews have been published to summarize the tea catechins' antioxidative, anti-inflammatory, and anti-apoptosis effects in the context of various diseases, such as cardiovascular diseases, cancers, and metabolic diseases. However, recent studies on tea catechins, especially the most abundant (-)-Epigallocatechin-3-Gallate (EGCG), revealed their capabilities in regulating cardiac muscle contraction by directly altering myofilament Ca2+ sensitivity on force development and Ca2+ ion handling in cardiomyocytes under both physiological and pathological conditions. In vitro and in vivo data also demonstrated that green tea extract or EGCG protected or rescued cardiac function, independent of their well-known effects against oxidative stress and inflammation. This minireview will focus on the specific effects of tea catechins on heart muscle contractility at the molecular and cellular level, revisit their effects on oxidative stress and inflammation in a variety of heart diseases, and discuss EGCG's potential as one of the lead compounds for new drug discovery for heart diseases.

Key Roles of Inflammation in Atherosclerosis: Mediators Involved in Orchestrating the Inflammatory Response and Its Resolution in the Disease Along with Therapeutic Avenues Targeting Inflammation

Inflammation is a critical driver of all stages of atherosclerosis, from lesion development to plaque rupture. Cytokines are mediators of the immune response and in atherosclerosis, the balance of anti- and pro-inflammatory cytokines is tipped in favor of the latter, resulting in persistent and unresolved inflammation. Although reducing plasma cholesterol levels mainly via the use of statins has positively impacted patient outcomes and reduced mortality rates, the presence of significant residual inflammation and cardiovascular risk posttherapy emphasizes the prevailing risk of primary and secondary events driven by inflammation independently of hyperlipidemia. Given the dominant role of inflammation in driving pathogenesis, alternative therapeutic avenues beyond targeting lowering of plasma lipids are required. This chapter will discuss the role of inflammation and pro-inflammatory cytokines in driving atherogenesis and disease progression, the therapeutic potential of targeting cytokines for atherosclerosis and promising avenues in this area.

Identification of potential genes associated with immune cell infiltration in atherosclerosis

BACKGROUND

This study aimed to analyze the potential genes associated with immune cell infiltration in atherosclerosis (AS).

METHODS

Gene expression profile data (GSE57691) of human arterial tissue samples were downloaded, and differentially expressed RNAs (DERNAs; long-noncoding RNA [lncRNAs], microRNAs [miRNAs], and messenger RNAs [mRNAs]) in AS vs. control groups were selected. Based on genome-wide expression levels, the proportion of infiltrating immune cells in each sample was assessed. Genes associated with immune infiltration were selected, and subjected to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Finally, a competing endogenous RNA (ceRNA) network was constructed, and the genes in the network were subjected to functional analyses.

RESULTS

A total of 1749 DERNAs meeting the thresholds were screened, including 1673 DEmRNAs, 63 DElncRNAs, and 13 DEmiRNAs. The proportions of B cells, CD4+ T cells, and CD8+ T cells were significantly different between the two groups. In total, 341 immune-associated genes such as HBB, FCN1, IL1B, CXCL8, RPS27A, CCN3, CTSZ, and SERPINA3 were obtained that were enriched in 70 significantly related GO biological processes (such as immune response) and 15 KEGG pathways (such as chemokine signaling pathway). A ceRNA network, including 33 lncRNAs, 11 miRNAs, and 216 mRNAs, was established.

CONCLUSION

Genes such as FCN1, IL1B, and SERPINA3 may be involved in immune cell infiltration and may play important roles in AS progression via ceRNA regulation.

Lipid Profile and IL-17A in Allergic Rhinitis: Correlation With Disease Severity and Quality of Life

BACKGROUND

Recent data display the possible role of cytokines such as interleukin-10 (IL-10), IL-17 and IL-23 as a link between dyslipidemia and atopy; however, the relationship between dyslipidemia, allergic rhinitis (AR), and the underlying mechanisms involved is unclear.

PURPOSE

To measure the lipid profile and IL-17A level in AR patients in comparison to healthy controls, and correlate serum lipid level with the severity of symptoms and quality of life (QoL) of AR patients.

PATIENTS AND METHODS

Peripheral blood samples were collected from AR patients (n=70) and a control group (n=80). Samples were analyzed for serum total IgE by ELISA, serum lipid profile, and IL-17A level by ELISA. Severity of AR symptoms was assessed by visual analogue scale (VAS) score and the rhinoconjunctivitis QoL questionnaire.

RESULTS

Serum lipid profile and level of IL-17A in AR patients were significantly higher in comparison to controls (P < 0.001). Positive correlations were found between total cholesterol (TC) and the severity of AR and QoL. IL-17A was positively correlated with triglyceride (TG) level and low-density lipoprotein cholesterol (LDL-C) (P=0.011, r=0.303; P=0.043, r=0.242, respectively). Additionally, IL-17A was negatively correlated with high-density lipoprotein cholesterol (HDL-C) level (P=0.036, r=-0.251). IL-17A was positively correlated with both age and VAS score with statistical significance (P=0.033, r=0.225; P=0.011, r=0.302, respectively).

CONCLUSION

Dyslipidemia might play a potential role in the severity of AR symptoms and impairment of patients' QoL. Highlighting this association might alert physicians to evaluate the lipid profile in AR patients for timely diagnosis and treatment of dyslipidemia in an attempt to improve disease control and improve QoL.

Extrasystolic arrhythmia: is it an additional risk factor of atherosclerosis?

BACKGROUND

Extrasystolic arrhythmia is not included in the list of risk factors of atherosclerosis. The aim of this investigation was to determine the relationship between atherosclerosis of main arteries and extrasystolic arrhythmia.

METHODS

We included 286 patients in our investigation. We performed 24-hours ECG monitoring, blood lipids analysis, transthoracic echocardiography, ultrasound Doppler of brachiocephalic arteries, abdominal aorta branches, lower extremities arteries, renal arteries. If prescribed we performed stress echocardiography, transesophageal echocardiography, coronary angiography, renal arteries angiography, pancerebral angiography. So, the investigation was made for the active revealing of atherosclerotic signs. The main parameters of heart biomechanics and main arteries kinetics we calculated using apexcardiography and sphygmography and included: speed, acceleration, power, work in each phase of the cardiocycle by apexcardiography, as well as in period of prevalence of inflow over outflow and in period of prevalence of outflow over inflow in sphygmography. All the patients were divided into two main groups according to the quantity of extrasystoles per 24 hours: 1 group - less than 3000, 2 group -3000 extrasystoles and more per 24 hours.

RESULTS

We determined that the atherosclerotic process was more advanced and more often the group 2. The atherosclerosis was more severe in patients with extrasystoles before the mitral valve opening and in fast ventricles' filling phase in cardiocycle. The main parameters of heart biomechanics and main arteries kinetics (speed, acceleration, power, work) calculated by apexcardiography and sphygmography increased with the further tendency: if earlier extrasystole appears in cardiocycle, than more changes were observed. Analyzing the methods of physics for fluid movement - Newton equation for liquids and Reynold number - we demonstrated that in extrasystolic arrhythmia in first post-extrasystolic wave there are the conditions for the turbulent blood flow that can cause the onset and progressing of atherosclerotic process.

CONCLUSIONS

Extrasystolic arrhythmia is an additional risk factor of main arteries atherosclerosis. Especially this thesis is fair for the extrasystoles that appear in cardiocycle before the mitral valve opening and in fast ventricles' filling phase.

In silico analysis of the molecular regulatory networks in peripheral arterial occlusive disease

BACKGROUND

Peripheral arterial occlusive disease (PAOD) is a global public health concern that decreases the quality of life of the patients and can lead to disabilities and death. The aim of this study was to identify the genes and pathways associated with PAOD pathogenesis, and the potential therapeutic targets.

METHODS

Differentially expressed genes (DEGs) and miRNAs related to PAOD were extracted from the GSE57691 dataset and through text mining. Additionally, bioinformatics analysis was applied to explore gene ontology, pathways and protein-protein interaction of those DEGs. The potential miRNAs targeting the DEGs and the transcription factors (TFs) regulating miRNAs were predicted by multiple different databases.

RESULTS

A total of 59 DEGs were identified, which were significantly enriched in the inflammatory response, immune response, chemokine-mediated signaling pathway and JAK-STAT signaling pathway. Thirteen genes including IL6, CXCL12, IL1B, and STAT3 were hub genes in protein-protein interaction network. In addition, 513 miRNA-target gene pairs were identified, of which CXCL12 and PTPN11 were the potential targets of miRNA-143, and IL1B of miRNA-21. STAT3 was differentially expressed and regulated 27 potential target miRNAs including miRNA-143 and miRNA-21 in TF-miRNA regulatory network.

CONCLUSION

In summary, inflammation, immune response and STAT3-mediated miRNA-target genes axis play an important role in PAOD development and progression.

Tumor Necrosis Factor-Like Weak Inducer of Apoptosis (TWEAK)/Fibroblast Growth Factor-Inducible 14 (Fn14) Axis in Cardiovascular Diseases: Progress and Challenges

Cardiovascular diseases (CVD) are the leading cause of mortality in Western countries. CVD include several pathologies, such as coronary artery disease, stroke, peripheral artery disease, and aortic aneurysm, among others. All of them are characterized by a pathological vascular remodeling in which inflammation plays a key role. Interaction between different members of the tumor necrosis factor superfamily and their cognate receptors induce several biological actions that may participate in CVD. The cytokine tumor necrosis factor-like weak inducer of apoptosis (TWEAK) and its functional receptor, fibroblast growth factor-inducible 14 (Fn14), are abundantly expressed during pathological cardiovascular remodeling. The TWEAK/Fn14 axis controls a variety of cellular functions, such as proliferation, differentiation, and apoptosis, and has several biological functions, such as inflammation and fibrosis that are linked to CVD. It has been demonstrated that persistent TWEAK/Fn14 activation is involved in both vessel and heart remodeling associated with acute and chronic CVD. In this review, we summarized the role of the TWEAK/Fn14 axis during pathological cardiovascular remodeling, highlighting the cellular components and the signaling pathways that are involved in these processes.

Up-regulation of MIAT aggravates the atherosclerotic damage in atherosclerosis mice through the activation of PI3K/Akt signaling pathway

This study is performed to elucidate the role of long non-coding RNA myocardial infarction associated transcript (lncRNA MIAT) in vulnerable plaque formation in rats with atherosclerosis (AS) through the regulation of the PI3K/Akt signaling pathway. The mice model of AS was established, and the successful modeled AS mice were treated with overexpressed MIAT and silenced MIAT. The levels of blood lipids, atherosclerotic plaques (AP) formation, the lipid content, collagen content, apoptosis of aortic cells, angiogenesis as well as the expression of inflammatory factors, such as tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) were determined through a series of experiments. MIAT was found to be upregulated in AS. Additionally, MIAT up-regulated the levels of blood lipids, promoted AP formation, increased the lipid content and decreased the collagen content of AP, promoted the apoptosis of aortic cells in AS mice by activating the PI3K/Akt signaling pathway. Meanwhile, MIAT was determined to promote angiogenesis as well as the expression of inflammatory factors (IL-1β, IL-6, and TNF-α) in AS mice through the activation of the PI3K/Akt signaling pathway. Furthermore, MIAT activated the PI3K/Akt signaling pathway to participate in AS progression. Our study suggests that upregulation of MIAT can aggravate AS injury in AS mice via the activation of the PI3K/Akt signaling pathway, which could provide a novel target for the treatment of AS.

Atherosclerosis

Atherosclerosis, the formation of fibrofatty lesions in the artery wall, causes much morbidity and mortality worldwide, including most myocardial infarctions and many strokes, as well as disabling peripheral artery disease. Development of atherosclerotic lesions probably requires low-density lipoprotein, a particle that carries cholesterol through the blood. Other risk factors for atherosclerosis and its thrombotic complications include hypertension, cigarette smoking and diabetes mellitus. Increasing evidence also points to a role of the immune system, as emerging risk factors include inflammation and clonal haematopoiesis. Studies of the cell and molecular biology of atherogenesis have provided considerable insight into the mechanisms that link all these risk factors to atheroma development and the clinical manifestations of this disease. An array of diagnostic techniques, both invasive (such as selective coronary arteriography) and noninvasive (such as blood biomarkers, stress testing, CT and nuclear scanning), permit assessment of cardiovascular disease risk and targeting of therapies. An expanding armamentarium of therapies that can modify risk factors and confer clinical benefit is available; however, we face considerable challenge in providing equitable access to these treatments and in maximizing adherence. Yet, the clinical application of the fruits of research has advanced preventive strategies, enhanced clinical outcomes in affected individuals, and improved their quality of life. Rapidly accelerating knowledge and continued research promise to provide further progress in combating this common chronic disease.

Novel Antiatherosclerotic Therapies

Many measures can control lipid risk factors for atherosclerosis. Yet, even with excellent control of dyslipidemia, other sources of risk remain. Hence, we must look beyond lipids to address residual risk. Lifestyle measures should form the foundation of cardiovascular risk control. Many pharmacological interventions targeting oxidation have proven disappointing. A large program tested inhibition of a LpPLA2 (lipoprotein-associated phospholipase A2), culminating in 2 large-scale clinical trials that did not meet their primary end points. A variety of antioxidants have not shown benefit in clinical trials. Numerous laboratory and clinical studies have inculpated inflammatory pathways in the pathogenesis of atherosclerotic events. The p38 MAPK (mitogen-activated protein kinase) inhibitor losmapimod and an inhibitor of a leukocyte adhesion molecule, P-selectin, did not alter adverse events in trials. Low-dose methotrexate, despite the promising observational studies, did not lower biomarkers of inflammation or alter cardiovascular outcomes in the CIRT (cardiovascular inflammation reduction trial). Four large-scale investigations underway will determine colchicine's ability to reduce recurrent events in secondary prevention. The CANTOS (Canakinumab Anti-inflammatory Thrombosis Outcomes Study) showed that an antibody that neutralizes IL (interleukin)-1β can reduce recurrent cardiovascular events in secondary prevention. The success of CANTOS points to the pathway that leads from the NLRP3 (NOD-like receptor family, pyrin domain-containing protein 3) inflammasome through IL-1β to IL-6 as an attractive target for further study and clinical development beyond lipid therapies to address the unacceptable burden of risk that remains despite our best current care in secondary prevention.

Semaphorin 7A Promotes VEGFA/VEGFR2-Mediated Angiogenesis and Intraplaque Neovascularization in ApoE-/- Mice

Excessive neovascularization of atherosclerotic lesions increases plaque vulnerability and the susceptibility to rupture. Semaphorin 7A (Sema7A), a semaphorin family member, was recently reported to promote atherosclerotic plaque formation by mediating d-flow-induced endothelial phenotypic change and leukocyte adhesion. To extend our understanding of the proatherogenic role of Sema7A, we investigated the role of endothelial Sema7A in angiogenesis and atherosclerotic neovascularization. Sema7A overexpression in human umbilical vein endothelial cells (HUVECs) significantly upregulated VEGFA/VEGFR2 and promoted cell migration and angiogenesis. This enhancing effect was eliminated by the blockage of Sema7A receptor, β1 integrin. Inhibition of FAK or ERK1/2 downstream of β1 integrin signaling significantly inhibited cell migration and angiogenesis via ROCK (Rho-associated coiled forming protein kinase) and MYPT (myosin phosphatase targeting subunit), which are responsible for actin polymerization. Consistently, in vivo studies showed a remarkable reduction in VEGFA/VEGFR2 expression and neovascularization in the atherosclerotic plaques of Sema7A^-/-ApoE^-/- mice compared with Sema7A^+/+ApoE^-/- littermates. Supportively, Sema7A deficiency reduced the accumulation of T cells, macrophages, and dendritic cells, and enhanced plaque stability in ApoE^-/- mice. Together, our findings show that Sema7A promotes VEGFA/VEGFR2-mediated neovascularization in a β1 integrin-dependent manner, supporting a crucial role of Sema7A in the progression of human atherosclerosis.

Inflammation, Immunity, and Infection in Atherothrombosis: JACC Review Topic of the Week

Observations on human and experimental atherosclerosis, biomarker studies, and now a large-scale clinical trial support the operation of immune and inflammatory pathways in this disease. The factors that incite innate and adaptive immune responses implicated in atherogenesis and in lesion complication include traditional risk factors such as protein and lipid components of native and modified low-density lipoprotein, angiotensin II, smoking, visceral adipose tissue, and dysmetabolism. Infectious processes and products of the endogenous microbiome might also modulate atherosclerosis and its complications either directly, or indirectly by eliciting local and systemic responses that potentiate disease expression. Trials with antibiotics have not reduced recurrent cardiovascular events, nor have vaccination strategies yet achieved clinical translation. However, anti-inflammatory interventions such as anticytokine therapy and colchicine have begun to show efficacy in this regard. Thus, inflammatory and immune mechanisms can link traditional and emerging risk factors to atherosclerosis, and offer novel avenues for therapeutic intervention.

Interactions between dyslipidemia and the immune system and their relevance as putative therapeutic targets in atherosclerosis

Cardiovascular disease (CVD) continues to be a leading cause of death worldwide with atherosclerosis being the major underlying pathology. The interplay between lipids and immune cells is believed to be a driving force in the chronic inflammation of the arterial wall during atherogenesis. Atherosclerosis is initiated as lipid particles accumulate and become trapped in vessel walls. The subsequent immune response, involving both adaptive and immune cells, progresses plaque development, which may be exacerbated under dyslipidemic conditions. Broad evidence, especially from animal models, clearly demonstrates the effect of lipids on immune cells from their development in the bone marrow to their phenotypic switching in circulation. Interestingly, recent research has also shown a long-lasting epigenetic signature from lipids on immune cells. Traditionally, cardiovascular therapies have approached atherosclerosis through lipid-lowering medications because, until recently, anti-inflammatory therapies have been largely unsuccessful in clinical trials. However, the recent Canakinumab Antiinflammatory Thrombosis Outcomes Study (CANTOS) provided pivotal support of the inflammatory hypothesis of atherosclerosis in man spurring on anti-inflammatory strategies to treat atherosclerosis. In this review, we describe the interactions between lipids and immune cells along with their specific outcomes as well as discuss their future perspective as potential cardiovascular targets.

The role of infiltrating immune cells in dysfunctional adipose tissue

Adipose tissue (AT) dysfunction, characterized by loss of its homeostatic functions, is a hallmark of non-communicable diseases. It is characterized by chronic low-grade inflammation and is observed in obesity, metabolic disorders such as insulin resistance and diabetes. While classically it has been identified by increased cytokine or chemokine expression, such as increased MCP-1, RANTES, IL-6, interferon (IFN) gamma or TNFα, mechanistically, immune cell infiltration is a prominent feature of the dysfunctional AT. These immune cells include M1 and M2 macrophages, effector and memory T cells, IL-10 producing FoxP3+ T regulatory cells, natural killer and NKT cells and granulocytes. Immune composition varies, depending on the stage and the type of pathology. Infiltrating immune cells not only produce cytokines but also metalloproteinases, reactive oxygen species, and chemokines that participate in tissue remodelling, cell signalling, and regulation of immunity. The presence of inflammatory cells in AT affects adjacent tissues and organs. In blood vessels, perivascular AT inflammation leads to vascular remodelling, superoxide production, endothelial dysfunction with loss of nitric oxide (NO) bioavailability, contributing to vascular disease, atherosclerosis, and plaque instability. Dysfunctional AT also releases adipokines such as leptin, resistin, and visfatin that promote metabolic dysfunction, alter systemic homeostasis, sympathetic outflow, glucose handling, and insulin sensitivity. Anti-inflammatory and protective adiponectin is reduced. AT may also serve as an important reservoir and possible site of activation in autoimmune-mediated and inflammatory diseases. Thus, reciprocal regulation between immune cell infiltration and AT dysfunction is a promising future therapeutic target.

Interleukin-1 Beta as a Target for Atherosclerosis Therapy: Biological Basis of CANTOS and Beyond

Inflammatory pathways drive atherogenesis and link conventional risk factors to atherosclerosis and its complications. One inflammatory mediator has come to the fore as a therapeutic target in cardiovascular disease. The experimental and clinical evidence reviewed here support interleukin-1 beta (IL-1β) as both a local vascular and systemic contributor in this regard. Intrinsic vascular wall cells and lesional leukocytes alike can produce this cytokine. Local stimuli in the plaque favor the generation of active IL-1β through the action of a molecular assembly known as the inflammasome. Clinically applicable interventions that interfere with IL-1 action can improve cardiovascular outcomes, ushering in a new era of anti-inflammatory therapies for atherosclerosis. The translational path described here illustrates how advances in basic vascular biology may transform therapy. Biomarker-directed application of anti-inflammatory interventions promises to help us achieve a more precise and personalized allocation of therapy for our cardiovascular patients.

[Oxidized low-density lipoprotein modulates differentiation of murine memory CD8+ T cell subpopulations]

OBJECTIVE

To investigate effect of oxidized low-density lipoprotein (ox-LDL) on memory CD8⁺ T cell subpopulation differentiation in mice with autoimmune diabetes.

METHODS

Cultured splenic CD8⁺ T cells from pre-diabetic NOD mice isolated with magnetic beads were treated with 30 µg/mL ox-LDL and 10 U/mL interleukin-2 (IL-2) for 24 h and the control cells were treated with IL-2 only. Flow cytometry was used to determine the percentage of splenic CD8⁺IFN-γ⁺ T cells, expressions of CD8, CD44 and CD62L on the T cells, and the activation of T cell factor-1 (TCF-1) and STAT-3. The CD127⁺ memory T cells were purified and transplanted into the pre-diabetic NOD mice via the tail vein, and the blood glucose was recorded weekly and survival time of the mice was monitored.

RESULTS

Treatment with ox-LDL significantly reduced islet β cell-specific cytotoxic CD8⁺T cells as compared with the control group [(0.7∓0.03)% vs (2.7∓0.14)%, P<0.01]. The percentage of effector memory CD8⁺T cells (Tem) in the total memory CD8⁺T cells was reduced [(10.3∓0.71)% vs (30.3∓1.36)%, P<0.01] and that of stem cell-like memory T cells was significantly increased [(72.3∓3.8)% vs (55.1∓2.61)%, P<0.05] following ox-LDL treatment, which also resulted in significantly decreased activation of TCF-1 [(14.5∓0.82)% vs (34.2∓1.23)%, P<0.01] and pSTAT-3 [(3.3∓0.12)% vs (22.1∓1.1)%, P<0.01]. Transplantation of ox-LDL-treated memory T cells in pre-diabetic NOD mice obviously inhibited the increase of blood glucose and prolonged the survival time of the mice (P<0.05).

CONCLUSION

Ox-LDL decreases the activation of transcriptional factors TCF-1 and phosphorylation of STAT-3, inhibits the formation of effector memory CD8⁺ T cells with long-term cytotoxicity, but promote the generation of stem cell-like memory CD8⁺ T cells, which result in suppression of islet β cell-specific effector cytotoxic CD8⁺ T cell differentiation to lessen autoimmune injury to the islet β cells.