Smooth Muscle Cells Contribute the Majority of Foam Cells in ApoE (Apolipoprotein E)-Deficient Mouse Atherosclerosis

Objective- Smooth muscle cells (SMCs) are the most abundant cells in human atherosclerotic lesions and are suggested to contribute at least 50% of atheroma foam cells. In mice, SMCs contribute fewer total lesional cells. The purpose of this study was to determine the contribution of SMCs to total foam cells in apolipoprotein E-deficient (ApoE^-/-) mice, and the utility of these mice to model human SMC foam cell biology and interventions. Approach and Results- Using flow cytometry, foam cells in the aortic arch of ApoE^-/- mice were characterized based on the expression of leukocyte-specific markers. Nonleukocyte foam cells increased from 37% of total foam cells in 27-week-old to 75% in 57-week-old male ApoE^-/- mice fed a chow diet and were ≈70% in male and female ApoE^-/- mice following 6 weeks of Western diet feeding. A similar contribution to total foam cells by SMCs was found using SMC-lineage tracing ApoE^-/- mice fed the Western diet for 6 or 12 weeks. Nonleukocyte foam cells contributed a similar percentage of total atheroma cholesterol and exhibited lower expression of the cholesterol exporter ABCA1 (ATP-binding cassette transporter A1) when compared with leukocyte-derived foam cells. Conclusions- Consistent with previous studies of human atheromas, we present evidence that SMCs contribute the majority of atheroma foam cells in ApoE^-/- mice fed a Western diet and a chow diet for longer periods. Reduced expression of ABCA1, also seen in human intimal SMCs, suggests a common mechanism for formation of SMC foam cells across species, and represents a novel target to enhance atherosclerosis regression.

Statins Disrupt Macrophage Rac1 Regulation Leading to Increased Atherosclerotic Plaque Calcification

OBJECTIVE

Calcification of atherosclerotic plaque is traditionally associated with increased cardiovascular event risk; however, recent studies have found increased calcium density to be associated with more stable disease. 3-hydroxy-3-methylglutaryl coenzymeA reductase inhibitors or statins reduce cardiovascular events. Invasive clinical studies have found that statins alter both the lipid and calcium composition of plaque but the molecular mechanisms of statin-mediated effects on plaque calcium composition remain unclear. We recently defined a macrophage Rac (Ras-related C3 botulinum toxin substrate)-IL-1β (interleukin-1 beta) signaling axis to be a key mechanism in promoting atherosclerotic calcification and sought to define the impact of statin therapy on this pathway. Approach and Results: Here, we demonstrate that statin therapy is independently associated with elevated coronary calcification in a high-risk patient population and that statins disrupt the complex between Rac1 and its inhibitor RhoGDI (Rho GDP-dissociation inhibitor), leading to increased active (GTP bound) Rac1 in primary monocytes/macrophages. Rac1 activation is prevented by rescue with the isoprenyl precursor geranylgeranyl diphosphate. Statin-treated macrophages exhibit increased activation of NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells), increased IL-1β mRNA, and increased Rac1-dependent IL-1β protein secretion in response to inflammasome stimulation. Using an animal model of calcific atherosclerosis, inclusion of statin in the atherogenic diet led to a myeloid Rac1-dependent increase in atherosclerotic calcification, which was associated with increased serum IL-1β expression, increased plaque Rac1 activation, and increased plaque expression of the osteogenic markers, alkaline phosphatase and RUNX2 (Runt-related transcription factor 2).

CONCLUSIONS

Statins are capable of increasing atherosclerotic calcification through disinhibition of a macrophage Rac1-IL-1β signaling axis.

Long Non-Coding RNAs Link Oxidized Low-Density Lipoprotein With the Inflammatory Response of Macrophages in Atherogenesis

Atherosclerosis is characterized as a chronic inflammatory response to cholesterol deposition in arteries. Low-density lipoprotein (LDL), especially the oxidized form (ox-LDL), plays a crucial role in the occurrence and development of atherosclerosis by inducing endothelial cell (EC) dysfunction, attracting monocyte-derived macrophages, and promoting chronic inflammation. However, the mechanisms linking cholesterol accumulation with inflammation in macrophage foam cells are poorly understood. Long non-coding RNAs (lncRNAs) are a group of non-protein-coding RNAs longer than 200 nucleotides and are found to regulate the progress of atherosclerosis. Recently, many lncRNAs interfering with cholesterol deposition or inflammation were identified, which might help elucidate their underlying molecular mechanism or be used as novel therapeutic targets. In this review, we summarize and highlight the role of lncRNAs linking cholesterol (mainly ox-LDL) accumulation with inflammation in macrophages during the process of atherosclerosis.

Pooled cohort risk equation and subclinical cerebrovascular diseases

BACKGROUND AND PURPOSE

In 2013, the American College of Cardiology/American Heart Association (ACC/AHA) introduced a novel pooled cohort risk (PCR) model for atherosclerotic cardiovascular disease. In this study, we evaluated the relationship between the PCR score and cerebral large- and small-vessel diseases (cLVD and cSVD) in a healthy population, METHODS: We assessed consecutive health check-up volunteers from 2006 to 2013. We calculated the estimated 10-year atherosclerotic cardiovascular disease risk as the PCR score based on the 2013 ACC/AHA guidelines. We evaluated both cSVD/cLVD, including the prevalence of cLVD, lacunes and cerebral microbleed (CMB), and the volume of white matter hyperintensity (WMH). In addition to PCR score, the risk factors that were associated with outcome variables at P < 0.10 in univariate analysis were included for further multivariable linear or regression analyses.

RESULTS

A total of 2720 participants were evaluated (mean age, 57 years, male sex, 54%). In multivariable analysis, PCR score was associated with WMH volume [β = 0.361; 95% confidence interval (CI), 0.320-0.402, P < 0.001], cLVD [adjusted odds ratio (aOR), 1.66; 95% CI, 1.29-2.16, P < 0.001], lacunes (aOR, 1.80; 95% CI, 1.52-2.14, P < 0.001) and CMBs (aOR, 1.75; 95% CI, 1.40-2.19, P < 0.001). Furthermore, PCR score also showed dose-response tendencies according to the burden of cLVD, WMH, lacunes and CMB.

CONCLUSIONS

A higher PCR score based on the ACC/AHA guidelines is closely associated with a higher prevalence and burden of cLVD and cSVD.

Integrating Network Pharmacology and Component Analysis Study on Anti-Atherosclerotic Mechanisms of Total Flavonoids of Engelhardia roxburghiana Leaves in Mice

Engelhardia roxburghiana Wall. leaves are widely used to develop herbal teas in southeast of China due to medicinal use for diabetes mellitus and hyperlipidemia. Studies have demonstrated that the total flavonoids of E. roxburghiana leaves (TFER) exhibited regulatory effects on blood glucose and lipids. To clarify the active ingredients of TFER and their targets in treating atherosclerosis, the present study integrated chemical analysis, network pharmacology analysis and animal experimental studies. Firstly, high performance liquid chromatography-mass spectrometry/mass spectrometry (HPLC/MS/MS) was utilized to identify components of TFER. Then, active ingredients were screened by oral bioavailability (OB) and drug-likeness (DL) index. Thirdly, network was constructed to predict major targets of active ingredients against atherosclerosis. Finally, to verify parts of predicted signaling, Apoe^-/- mice were used to develop atherosclerosis. Atherosclerotic plaques in aorta were evaluated by echocardiography. Then, serum lipids, target genes expressions in thoracic aorta were determined by qRT-PCR and ELISA methods. Chemical analysis revealed 10 components in TFER sample, 7 of which acted as active ingredients, including naringenin, kaempferol, quercetin, isoengeletin, engeletin, astilbin and quercitrin. KEGG pathway analysis highly enriched in some inflammatory signalings, including NF-κB signaling, Toll-like receptor signaling and TNF signaling. The animal studies indicated that TFER reduced atherosclerotic plaques size in aorta and significantly decreased the serum lipids, down-regulated NF-κB signaling by decreasing mRNA level of NF-κB p65 subunit, TNF-α and VCAM-1, as well as IL-1β expressions in thoracic aorta, eventually alleviating atherosclerosis progression, which was in consistent with our prediction.

Emerging Magnetic Resonance Imaging Techniques for Atherosclerosis Imaging

Atherosclerosis is a prevalent disease affecting a large portion of the population at one point in their lives. There is an unmet need for noninvasive diagnostics to identify and characterize at-risk plaque phenotypes noninvasively and in vivo, to improve the stratification of patients with cardiovascular disease, and for treatment evaluation. Magnetic resonance imaging is uniquely positioned to address these diagnostic needs. However, currently available magnetic resonance imaging methods for vessel wall imaging lack sufficient discriminative and predictive power to guide the individual patient needs. To address this challenge, physicists are pushing the boundaries of magnetic resonance atherosclerosis imaging to increase image resolution, provide improved quantitative evaluation of plaque constituents, and obtain readouts of disease activity such as inflammation. Here, we review some of these important developments, with specific focus on emerging applications using high-field magnetic resonance imaging, the use of quantitative relaxation parameter mapping for improved plaque characterization, and novel ¹⁹F magnetic resonance imaging technology to image plaque inflammation.

IgE Contributes to Atherosclerosis and Obesity by Affecting Macrophage Polarization, Macrophage Protein Network, and Foam Cell Formation

OBJECTIVE

By binding to its high-affinity receptor FcεR1, IgE activates mast cells, macrophages, and other inflammatory and vascular cells. Recent studies support an essential role of IgE in cardiometabolic diseases. Plasma IgE level is an independent predictor of human coronary heart disease. Yet, a direct role of IgE and its mechanisms in cardiometabolic diseases remain incompletely understood. Approach and Results: Using atherosclerosis prone Apoe^-/- mice and IgE-deficient Ige^-/- mice, we demonstrated that IgE deficiency reduced atherosclerosis lesion burden, lesion lipid deposition, smooth muscle cell and endothelial cell contents, chemokine MCP (monocyte chemoattractant protein)-1 expression and macrophage accumulation. IgE deficiency also reduced bodyweight gain and increased glucose and insulin sensitivities with significantly reduced plasma cholesterol, triglyceride, insulin, and inflammatory cytokines and chemokines, including IL (interleukin)-6, IFN (interferon)-γ, and MCP-1. From atherosclerotic lesions and peritoneal macrophages from Apoe^-/-Ige^-/- mice that consumed an atherogenic diet, we detected reduced expression of M1 macrophage markers (CD68, MCP-1, TNF [tumor necrosis factor]-α, IL-6, and iNOS [inducible nitric oxide synthase]) but increased expression of M2 macrophage markers (Arg [arginase]-1 and IL-10) and macrophage-sterol-responsive-network molecules (complement C3, lipoprotein lipase, LDLR [low-density lipoprotein receptor]-related protein 1, and TFR [transferrin]) that suppress macrophage foam cell formation. These IgE activities can be reproduced in bone marrow-derived macrophages from wild-type mice, but muted in cells from FcεR1-deficient mice, or blocked by anti-IgE antibody or complement C3 deficiency.

CONCLUSIONS

IgE deficiency protects mice from diet-induced atherosclerosis, obesity, glucose tolerance, and insulin resistance by regulating macrophage polarization, macrophage-sterol-responsive-network gene expression, and foam cell formation.

K63 ubiquitin chains target NLRP3 inflammasome for autophagic degradation in ox-LDL-stimulated THP-1 macrophages

Inflammation, especially involving the NLRP3 inflammasome, is critical to atherosclerotic plaque formation. Enhanced autophagy can inhibit the development of atherosclerosis, and recent studies have revealed that NLRP3 inflammasome can be degraded by autophagy in atherosclerosis. In the present study, we established a foam-cell model to investigate the impact of oxidized low density lipoproteins (ox-LDLs) on autophagy and the inflammasome in atherosclerosis-related inflammation. We observed that ox-LDLs activated NLRP3 inflammasomes in macrophages and restricted autophagy in a time-and dose-dependent manner. We further observed through immunoprecipitation and siRNA knockdown that autophagic degradation of the NLRP3 inflammasome is dependent on K63 polyubiquitation of its NLRP3 subunit and subsequent binding by the adaptor protein p62. Our findings uncover a mechanism by which autophagy inhibits inflammation in atherosclerosis and the role of K63 in that process.

Heme Oxygenase Dependent Bilirubin Generation in Vascular Cells: A Role in Preventing Endothelial Dysfunction in Local Tissue Microenvironment?

Among antioxidants in the human body, bilirubin has been recognized over the past 20 years to afford protection against different chronic conditions, including inflammation and cardiovascular disease. Moderate increases in plasma concentration and cellular bilirubin generation from metabolism of heme via heme oxygenase (HMOX) in virtually all tissues can modulate endothelial and vascular function and exert antioxidant and anti-inflammatory roles. This review aims to provide an up-to-date and critical overview of the molecular mechanisms by which bilirubin derived from plasma or from HMOX1 activation in vascular cells affects endothelial function. Understanding the molecular actions of bilirubin may critically improve the management not only of key cardiovascular diseases, but also provide insights into a broad spectrum of pathologies driven by endothelial dysfunction. In this context, therapeutic interventions aimed at mildly increasing serum bilirubin as well as bilirubin generated endogenously by endothelial HMOX1 should be considered.

Gut Microbiota and Its Metabolites in Atherosclerosis Development

Gut microbiota metabolites have a great influence on host digestive function and body health itself. The effects of intestinal microbes on the host metabolism and nutrients absorption are mainly due to regulatory mechanisms related to serotonin, cytokines, and metabolites. Multiple studies have repeatedly reported that the gut microbiota plays a fundamental role in the absorption of bioactive compounds by converting dietary polyphenols into absorbable bioactive substances. Moreover, some intestinal metabolites derived from natural polyphenol products have more biological activities than their own fundamental biological functions. Bioactive like polyphenolic compounds, prebiotics and probiotics are the best known dietary strategies for regulating the composition of gut microbial populations or metabolic/immunological activities, which are called “three “p” for gut health”. Intestinal microbial metabolites have an indirect effect on atherosclerosis, by regulating lipid metabolism and inflammation. It has been found that the diversity of intestinal microbiota negatively correlates with the development of atherosclerosis. The fewer the variation and number of microbial species in the gut, the higher the risk of developing atherosclerosis. Therefore, the atherosclerosis can be prevented and treated from the perspective of improving the number and variability of gut microbiota. In here, we summarize the effects of gut metabolites of natural products on the pathological process of the atherosclerosis, since gut intestinal metabolites not only have an indirect effect on macrophage foaming in the vessel wall, but also have a direct effect on vascular endothelial cells.

Nuclear Receptor Nur77 Limits the Macrophage Inflammatory Response through Transcriptional Reprogramming of Mitochondrial Metabolism

Activation of macrophages by inflammatory stimuli induces reprogramming of mitochondrial metabolism to support the production of pro-inflammatory cytokines and nitric oxide. Hallmarks of this metabolic rewiring are downregulation of α-ketoglutarate formation by isocitrate dehydrogenase (IDH) and accumulation of glutamine-derived succinate, which enhances the inflammatory response via the activity of succinate dehydrogenase (SDH). Here, we identify the nuclear receptor Nur77 (Nr4a1) as a key upstream transcriptional regulator of this pro-inflammatory metabolic switch in macrophages. Nur77-deficient macrophages fail to downregulate IDH expression and accumulate higher levels of succinate and other TCA cycle-derived metabolites in response to inflammatory stimulation in a glutamine-independent manner. Consequently, these macrophages produce more nitric oxide and pro-inflammatory cytokines in an SDH-dependent manner. In vivo, bone marrow Nur77 deficiency exacerbates atherosclerosis development and leads to increased circulating succinate levels. In summary, Nur77 induces an anti-inflammatory metabolic state in macrophages that protects against chronic inflammatory diseases such as atherosclerosis.

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Genome-wide profiling indicates that Nur77 regulates macrophage mitochondrial metabolism

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Nur77 inhibits IDH expression and TCA cycle activity in inflammatory macrophages

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Nur77-deficient macrophages produce more nitric oxide and cytokines via SDH

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Nur77 deficiency increases circulating succinate levels and atherosclerosis in vivo

Trouble With Tribbles-1

Genome-wide association studies (GWAS) have identified hundreds of genomic loci in humans that are significantly associated with plasma cholesterol, triglycerides, and coronary artery disease. Although some loci contain genes with known regulatory roles in lipid metabolism and atherosclerosis, the majority were being implicated for the first time. The 8q24 locus, containing the gene TRIB1 ( Tribbles-1), is the only novel GWAS locus that associates with all 4 plasma lipid traits and coronary artery disease, an observation that has spurred immense interest in this locus. Subsequent in vivo loss and gain of function studies confirmed that Trib1 plays a role in hepatic lipid metabolism, validating the initial genetic observation. Yet, many challenges remain in discerning the nature of the association between the TRIB1 locus and cardiometabolic phenotypes. Is TRIB1 the causal gene at the 8q24 locus and what is the functional consequence of the associated noncoding variation? Is the relationship between TRIB1 and the transcription factor C/EBPα (CCAAT/enhancer-binding protein alpha) the primary molecular mechanism governing the genetic association or could it be an as yet unknown function for this interesting pseudokinase? Is hepatic TRIB1 the sole regulator of lipid metabolism or could extrahepatic TRIB1 play a role as well? The following review summarizes key findings related to these questions and highlights both the challenges and excitement in pursuing translational research of a novel gene in the post-GWAS era.

Circulating Anti-Sorting Nexins 16 Antibodies as an Emerging Biomarker of Coronary Artery Disease in Patients with Obstructive Sleep Apnea

Biomarkers are not available for monitoring the onset and progression of coronary artery disease (CAD) in patients with obstructive sleep apnea (OSA), a major risk factor for arteriosclerotic cardiovascular diseases. This study aimed to test for correlation between circulating anti-Sorting Nexins 16 antibody (SNX16-Ab) levels, CAD history and clinical parameters of patients with OSA. Sixty-four healthy donors, 82 adults with OSA, and 96 with acute coronary syndrome (ACS) were studied. Serum samples were collected at diagnostic polysomnography in the OSA group or at the disease onset in the ACS group. Serum SNX16-Ab levels were measured by amplified luminescence proximity homogeneous assay (AlphaLISA), and correlation between SNX16-Ab levels and clinical parameters was analyzed. SNX16-Ab levels and apnea-hypopnea index (AHI) were weakly correlated. Additionally, logistic regression analyses of OSA group identified that elevated SNX16-Ab level associated with the history of CAD. Circulating SNX16-Ab could increase during CAD pathogenesis in patients with OSA. Further prospective studies are required to prove the predictive potential of SNX16-Ab level in CAD onset of patients with OSA.

Araloside C attenuates atherosclerosis by modulating macrophage polarization via Sirt1-mediated autophagy

Atherosclerosis-related cardiovascular disease is still the predominant cause of death worldwide. Araloside C (AsC), a natural saponin, exerts extensive anti-inflammatory properties. In this study, we explored the protective effects and mechanism of AsC on macrophage polarization in atherosclerosis in vivo and in vitro. Using a high-fat diet (HFD)-fed ApoE-/- mouse model and RAW264.7 macrophages exposed to ox-LDL, AsC was evaluated for its effects on polarization and autophagy. AsC significantly reduced the plaque area in atherosclerotic mice and lipid accumulation in ox-LDL-treated macrophages, promoted M2 phenotype macrophage polarization, increased the number of autophagosomes and modulated the expression of autophagy-related proteins. Moreover, the autophagy inhibitor 3-methyladenine and BECN1 siRNA obviously abolished the antiatherosclerotic and M2 macrophage polarization effects of AsC. Mechanistically, AsC targeted Sirt1and increased its expression, and this increase in expression was associated with increased autophagy and M2 phenotype polarization. In contrast, the effects of AsC were markedly blocked by EX527 and Sirt1 siRNA. Altogether, AsC attenuates foam cell formation and lessens atherosclerosis by modulating macrophage polarization via Sirt1-mediated autophagy.

Post Chikungunya Chronic Arthritis: Systemic Inflammatory Status Triggering Acute Coronary Syndrome

BACKGROUND

Atherosclerosis, inflammation and coronary plaque destabilization are linked to each other. Infections due to various microbes may trigger Acute Coronary Syndrome (ACS) by systemic inflammation cascade.

METHODS

We have evaluated the prevalence of Post Chikungunya Chronic Arthritis (PCCA) among 400 consecutive ACS patients (Case group) and compared with control group subjected to elective surgery by the prospective case-control observational study. Cases were excluded if standard criteria of ACS were not satisfied and in the control group if the patient suffered a Myocardial Infarction (MI) within 28 days of elective surgery. PCCA duration more than two years or serum IgM anti-CCP positive patients were also excluded from the case as well as a control group.

RESULTS

The case and control groups were similar except, less number of heart failure (O.R.7.3, 95% C.I. 3.3-15.9) and chronic kidney injury patients (O.R. 0.5, 95% C.I. 0.3-0.9) in the elective surgery (control) group. PCCA was present in 24 out of 400 ACS cases and 8 out of 400 control group. Among ACS case-patients, those suffering from PCCA tended to be younger and more often women, with more diabetes, hypertension, chronic kidney injury and high mean CRP. In unadjusted analysis PCCA was three times more common in the case versus control (O.R. 3.0, 95% C.I. 1.4- 6.4); results were indistinguishable after multidiscipline adjustment (O.R. 3.0, 95% C.I. 1.3-6.8).

CONCLUSION

PCCA is common among patients with ACS and post-infective systemic inflammation of PCCA may trigger plaque destabilization.

Role of Phagocytosis in the Pro-Inflammatory Response in LDL-Induced Foam Cell Formation; a Transcriptome Analysis

Excessive accumulation of lipid inclusions in the arterial wall cells (foam cell formation) caused by modified low-density lipoprotein (LDL) is the earliest and most noticeable manifestation of atherosclerosis. The mechanisms of foam cell formation are not fully understood and can involve altered lipid uptake, impaired lipid metabolism, or both. Recently, we have identified the top 10 master regulators that were involved in the accumulation of cholesterol in cultured macrophages induced by the incubation with modified LDL. It was found that most of the identified master regulators were related to the regulation of the inflammatory immune response, but not to lipid metabolism. A possible explanation for this unexpected result is a stimulation of the phagocytic activity of macrophages by modified LDL particle associates that have a relatively large size. In the current study, we investigated gene regulation in macrophages using transcriptome analysis to test the hypothesis that the primary event occurring upon the interaction of modified LDL and macrophages is the stimulation of phagocytosis, which subsequently triggers the pro-inflammatory immune response. We identified genes that were up- or downregulated following the exposure of cultured cells to modified LDL or latex beads (inert phagocytosis stimulators). Most of the identified master regulators were involved in the innate immune response, and some of them were encoding major pro-inflammatory proteins. The obtained results indicated that pro-inflammatory response to phagocytosis stimulation precedes the accumulation of intracellular lipids and possibly contributes to the formation of foam cells. In this way, the currently recognized hypothesis that the accumulation of lipids triggers the pro-inflammatory response was not confirmed. Comparative analysis of master regulators revealed similarities in the genetic regulation of the interaction of macrophages with naturally occurring LDL and desialylated LDL. Oxidized and desialylated LDL affected a different spectrum of genes than naturally occurring LDL. These observations suggest that desialylation is the most important modification of LDL occurring in vivo. Thus, modified LDL caused the gene regulation characteristic of the stimulation of phagocytosis. Additionally, the knock-down effect of five master regulators, such as IL15, EIF2AK3, F2RL1, TSPYL2, and ANXA1, on intracellular lipid accumulation was tested. We knocked down these genes in primary macrophages derived from human monocytes. The addition of atherogenic naturally occurring LDL caused a significant accumulation of cholesterol in the control cells. The knock-down of the EIF2AK3 and IL15 genes completely prevented cholesterol accumulation in cultured macrophages. The knock-down of the ANXA1 gene caused a further decrease in cholesterol content in cultured macrophages. At the same time, knock-down of F2RL1 and TSPYL2 did not cause an effect. The results obtained allowed us to explain in which way the inflammatory response and the accumulation of cholesterol are related confirming our hypothesis of atherogenesis development based on the following viewpoints: LDL particles undergo atherogenic modifications that, in turn, accompanied by the formation of self-associates; large LDL associates stimulate phagocytosis; as a result of phagocytosis stimulation, pro-inflammatory molecules are secreted; these molecules cause or at least contribute to the accumulation of intracellular cholesterol. Therefore, it became obvious that the primary event in this sequence is not the accumulation of cholesterol but an inflammatory response.

Understanding Atherosclerosis Through an Osteoarthritis Data Set

Atherosclerotic cardiovascular disease remains a worldwide epidemic and one of the leading causes of death nowadays. Vessel wall imaging can be used to understand the development and progression of atherosclerosis, but it is rarely done because of the high cost. We recently identified the Osteoarthritis Initiative, a large prospective cohort study of knee osteoarthritis, which might serve as a valuable source for atherosclerosis research with its serial knee magnetic resonance imaging data. We have found that these images are suitable for vessel wall image analysis of the lower extremity arteries. Here, we will introduce the Osteoarthritis Initiative data set and explain why it could be used for cardiovascular research purposes. Also, we will briefly comment on peripheral artery atherosclerosis as it is covered in the Osteoarthritis Initiative image data set and review the use of vessel wall imaging for studying atherosclerosis. We think data mining of imaging studies, not originally designed on cardiovascular research, can not only maximize the value of the imaging data set but also boost our understanding of atherosclerosis.

Genetic Deficiency of Flavin-Containing Monooxygenase 3 ( Fmo3) Protects Against Thrombosis but Has Only a Minor Effect on Plasma Lipid Levels-Brief Report

Objective- FMO (flavin-containing monooxygenase) 3 converts bacterial-derived trimethylamine to trimethylamine N-oxide (TMAO), an independent risk factor for cardiovascular disease. We generated FMO3 knockout (FMO3KO) mouse to study its effects on plasma TMAO, lipids, glucose/insulin metabolism, thrombosis, and atherosclerosis. Approach and Results- Previous studies with an antisense oligonucleotide (ASO) knockdown strategy targeting FMO3 in LDLRKO (low-density lipoprotein receptor knockout) mice resulted in major reductions in TMAO levels and atherosclerosis, but also showed effects on plasma lipids, insulin, and glucose. Although FMO3KO mice generated via CRISPR/Cas9 technology bred onto the LDLRKO background did exhibit similar effects on TMAO levels, the effects on lipid metabolism were not as pronounced as with the ASO knockdown model. These differences could result from either off-target effects of the ASO or from a developmental adaptation to the FMO3 deficiency. To distinguish these possibilities, we treated wild-type and FMO3KO mice with control or FMO3 ASOs. FMO3-ASO treatment led to the same extent of lipid-lowering effects in the FMO3KO mice as the wild-type mice, indicating off-target effects. The levels of TMAO in LDLRKO mice fed an atherogenic diet are very low in both wild-type and FMO3KO mice, and no significant effect was observed on atherosclerosis. When FMO3KO and wild-type mice were maintained on a 0.5% choline diet, FMO3KO showed a marked reduction in both TMAO and in vivo thrombosis potential. Conclusions- FMO3KO markedly reduces systemic TMAO levels and thrombosis potential. However, the previously observed large effects of an FMO3 ASO on plasma lipid levels appear to be due partly to off-target effects.

Methionine sulfoxide reductase A attenuates atherosclerosis via repairing dysfunctional HDL in scavenger receptor class B type I deficient mice

High-density lipoprotein (HDL), a well-known atheroprotective factor, can be converted to proatherogenic particles in chronic inflammation. HDL-targeted therapeutic strategy for atherosclerotic cardiovascular disease (CVD) is currently under development. This study aims to assess the role of methionine sulfoxide reductase A (MsrA) in abnormal HDL and its related disorders in scavenger receptor class B type I deficient (SR-BI^-/- ) mice. First, we demonstrated that MsrA overexpression attenuated ROS level and inflammation in HepG2 cells. For the in vivo study, SR-BI^-/- mice were intravenously injected with lentivirus to achieve hepatic MsrA overexpression. High-level hepatic MsrA significantly reduced the plasma free cholesterol contents, improved HDL functional proteins apolipoprotein A-I (apoAI), apoE, paraoxonase1 (PON1), and lecithin:cholesterol acyltransferase (LCAT), while decreased the pro-inflammatory property of dysfunctional HDL, contributing to reduced atherosclerosis and hepatic steatosis in Western diet-fed mice. Furthermore, the study revealed that hepatic MsrA altered the expression of several genes controlling HDL biogenesis, cholesterol esterification, cholesterol uptake mediated by low-density lipoprotein receptor (LDLR) and biliary excretion, as well as suppressed nuclear factor κB (NF-κB) signaling pathway, which largely relied on liver X receptor alpha (LXRα)-upregulation. These results provide original evidence that MsrA may be a promising target for the therapy of dysfunctional HDL-related CVD.

Genetic Risk of Coronary Artery Disease, Features of Atherosclerosis, and Coronary Plaque Burden

Background

Polygenic risk scores (PRSs) based on risk variants from genome‐wide association studies predict coronary artery disease (CAD) risk. However, it is unknown whether the PRS is associated with specific CAD characteristics.

Methods and Results

We consecutively included 1645 patients with suspected stable CAD undergoing coronary computed tomography angiography. A multilocus PRS was calculated as the weighted sum of CAD risk variants. Plaques were evaluated using an 18‐segment model and characterized by stenosis severity and composition (soft [0%‐19% calcified], mixed‐soft [20%‐49% calcified], mixed‐calcified [50%‐79% calcified], or calcified [≥80% calcified]). Coronary artery calcium score and segment stenosis score were used to characterize plaque burden. For each standard deviation increase in the PRS, coronary artery calcium score increased by 78% (P=4.1e‐26) and segment stenosis score increased by 16% (P=2.4e‐29) in the fully adjusted model. The PRS was associated with a higher prevalence of obstructive plaques (odds ratio [OR]: 1.78, P=5.6e‐16), calcified (OR: 1.69, P=6.5e‐17), mixed‐calcified (OR: 1.67, P=7.3e‐9), mixed‐soft (OR: 1.45, P=1.6e‐6), and soft plaques (OR: 1.49, P=2.5e‐6), and a higher prevalence of plaque in each coronary vessel (all P<1.0e‐4). However, when analyzing data on a plaque level (3007 segments with plaque in 849 patients) the PRS was not associated with stenosis severity, plaque composition, or localization (all P>0.05).

Conclusions

Our results suggest that polygenic risk based on large genome‐wide association studies increases CAD risk through an increased burden of coronary atherosclerosis rather than promoting specific plaque features.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov. Unique identifier: NCT02264717.

A novel technique for stenting in cases of refractory intracranial stenosis

Endovascular management of intracranial stenosis is one of the most controversial subjects in neurointervention. Previous level 1 evidence shows superiority of medical management but more recent studies have shown improved outcomes in selective patients. We describe a case demonstrating a new method for stenting of intracranial stenosis using a single system with Coyote angioplasty balloon (Boston Scientific) and the Atlas stent (Stryker).

A 6-month systems toxicology inhalation study in ApoE-/- mice demonstrates reduced cardiovascular effects of E-vapor aerosols compared with cigarette smoke

Smoking cigarettes is harmful to the cardiovascular system. Considerable attention has been paid to the reduced harm potential of alternative nicotine-containing inhalable products such as e-cigarettes. We investigated the effects of E-vapor aerosols or cigarette smoke (CS) on atherosclerosis progression, cardiovascular function, and molecular changes in the heart and aorta of female apolipoprotein E-deficient (ApoE^-/-) mice. The mice were exposed to aerosols from three different E-vapor formulations: 1) carrier (propylene glycol and vegetable glycerol), 2) base (carrier and nicotine), or 3) test (base and flavor) or to CS from 3R4F reference cigarettes for up to 6 mo. Concentrations of CS and base or test aerosols were matched at 35 µg nicotine/L. Exposure to CS, compared with sham-exposed fresh air controls, accelerated atherosclerotic plaque formation, whereas no such effect was seen for any of the three E-vapor aerosols. Molecular changes indicated disease mechanisms related to oxidative stress and inflammation in general, plus changes in calcium regulation, and altered cytoskeletal organization and microtubule dynamics in the left ventricle. While ejection fraction, fractional shortening, cardiac output, and isovolumic contraction time remained unchanged following E-vapor aerosols exposure, the nicotine-containing base and test aerosols caused an increase in isovolumic relaxation time similar to CS. A nicotine-related increase in pulse wave velocity and arterial stiffness was also observed, but it was significantly lower for base and test aerosols than for CS. These results demonstrate that in comparison with CS, E-vapor aerosols induce substantially lower biological responses associated with smoking-related cardiovascular diseases.NEW & NOTEWORTHY Analysis of key urinary oxidative stress markers and proinflammatory cytokines showed an absence of oxidative stress and inflammation in the animals exposed to E-vapor aerosols. Conversely, animals exposed to conventional cigarette smoke had high urinary levels of these markers. When compared with conventional cigarette smoke, E-vapor aerosols induced smaller atherosclerotic plaque surface area and volume. Systolic and diastolic cardiac function, as well as endothelial function, were further significantly less affected by electronic cigarette aerosols than conventional cigarette smoke. Molecular analysis demonstrated that E-vapor aerosols induce significantly smaller transcriptomic dysregulation in the heart and aorta compared with conventional cigarette smoke.

Correlation Between Ankle Brachial Index and Lower Limbs Digital Pulse Oximetry: A Referral Center Experience, Prevalence Study

Objective

Ankle-brachial index (ABI) is widely recommended and used to evaluate peripheral arterial disease. The oxygen saturation (SpO₂) has been associated with ABI, showing a promising clinical practice utility; however, little literature regarding this matter has been reported. This study aims to assess the correlation between pulse oximetry and ABI. 

Methods

A cross-sectional study was conducted using ABI measuring devices, such as the MESI® Ankle Brachial Pressure Index (ABPI) (MESI, Ltd., Slovenia, EU) and pulse oximetry. We compared the SpO₂ distribution by using the Wilcoxon test and evaluated its correlation by using logistic regression. 

Results

From a total of 86 patients, 54 were males (62.8%) and the median age was 54 years old (interquartile range (IQR) = 37 - 65 yrs.). Regarding ABI measurements of the right lower limb (RLL), a total of 20 patients (22.3%) had an abnormal classification. On the other hand, a total of 21 patients (22.1%) had an abnormal classification of the left lower limb (LLL) ABI measurements. The distribution of SpO₂ in relation to ABI categories was not statistically different (RLL p = 0.2433; LLL p = 0.1242). The SpO₂ classification of ABI and abnormal pulse oximetry for the RLL was at 76.7% and at 77.9% in the LLL (Pearson’s goodness-of-fit test: RLL = p < 0.001 and LLL = p < 0.001). 

Conclusion

Although we didn’t observe any statistical differences in the SpO₂ distribution regarding ABI measurements, in their correlation, there seems to be a different tendency. The SpO₂ might be a useful non-invasive tool to assess asymptomatic patients with risk factors for peripheral arterial disease (PAD).

The Role of Bone Morphogenetic Protein 7 (BMP-7) in Inflammation in Heart Diseases

Bone morphogenetic protein-7 is (BMP-7) is a potent anti-inflammatory growth factor belonging to the Transforming Growth Factor Beta (TGF-β) superfamily. It plays an important role in various biological processes, including embryogenesis, hematopoiesis, neurogenesis and skeletal morphogenesis. BMP-7 stimulates the target cells by binding to specific membrane-bound receptor BMPR 2 and transduces signals through mothers against decapentaplegic (Smads) and mitogen activated protein kinase (MAPK) pathways. To date, rhBMP-7 has been used clinically to induce the differentiation of mesenchymal stem cells bordering the bone fracture site into chondrocytes, osteoclasts, the formation of new bone via calcium deposition and to stimulate the repair of bone fracture. However, its use in cardiovascular diseases, such as atherosclerosis, myocardial infarction, and diabetic cardiomyopathy is currently being explored. More importantly, these cardiovascular diseases are associated with inflammation and infiltrated monocytes where BMP-7 has been demonstrated to be a key player in the differentiation of pro-inflammatory monocytes, or M1 macrophages, into anti-inflammatory M2 macrophages, which reduces developed cardiac dysfunction. Therefore, this review focuses on the molecular mechanisms of BMP-7 treatment in cardiovascular disease and its role as an anti-fibrotic, anti-apoptotic and anti-inflammatory growth factor, which emphasizes its potential therapeutic significance in heart diseases.