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Intestinal farnesoid X receptor (FXR) signaling is involved in the development of obesity, fatty liver disease, and type 2 diabetes. However, the role of intestinal FXR in atherosclerosis and its potential as a target for clinical treatment have not been explored. The serum levels of fibroblast growth factor 19 (FGF19), which is encoded by an FXR target gene, were much higher in patients with hypercholesterolemia than in control subjects and were positively related to circulating ceramide levels, indicating a link between intestinal FXR, ceramide metabolism, and atherosclerosis. Among ApoE-/- mice fed a high-cholesterol diet (HCD), intestinal FXR deficiency (in FxrΔIE ApoE-/- mice) or direct FXR inhibition (via treatment with the FXR antagonist glycoursodeoxycholic acid [GUDCA]) decreased atherosclerosis and reduced the levels of circulating ceramides and cholesterol. Sphingomyelin phosphodiesterase 3 (SMPD3), which is involved in ceramide synthesis in the intestine, was identified as an FXR target gene. SMPD3 overexpression or C16:0 ceramide supplementation eliminated the improvements in atherosclerosis in FxrΔIE ApoE-/- mice. Administration of GUDCA or GW4869, an SMPD3 inhibitor, elicited therapeutic effects on established atherosclerosis in ApoE-/- mice by decreasing circulating ceramide levels. This study identified an intestinal FXR/SMPD3 axis that is a potential target for atherosclerosis therapy.

Oxidized phospholipids (OxPL) are ubiquitous, are formed in many inflammatory tissues, including atherosclerotic lesions, and frequently mediate proinflammatory changes 1 . Because OxPL are mostly the products of non-enzymatic lipid peroxidation, mechanisms to specifically neutralize them are unavailable and their roles in vivo are largely unknown. We previously cloned the IgM natural antibody E06, which binds to the phosphocholine headgroup of OxPL, and blocks the uptake of oxidized low-density lipoprotein (OxLDL) by macrophages and inhibits the proinflammatory properties of OxPL 2 – 4 . Here, to determine the role of OxPL in vivo in the context of atherogenesis, we generated transgenic mice in the Ldlr −/− background that expressed a single-chain variable fragment of E06 (E06-scFv) using the Apoe promoter. E06-scFv was secreted into the plasma from the liver and macrophages, and achieved sufficient plasma levels to inhibit in vivo macrophage uptake of OxLDL and to prevent OxPL-induced inflammatory signalling. Compared to Ldlr −/− mice, Ldlr −/− E06-scFv mice had 57–28% less atherosclerosis after 4, 7 and even 12 months of 1% high-cholesterol diet. Echocardiographic and histologic evaluation of the aortic valves demonstrated that E06-scFv ameliorated the development of aortic valve gradients and decreased aortic valve calcification. Both cholesterol accumulation and in vivo uptake of OxLDL were decreased in peritoneal macrophages, and both peritoneal and aortic macrophages had a decreased inflammatory phenotype. Serum amyloid A was decreased by 32%, indicating decreased systemic inflammation, and hepatic steatosis and inflammation were also decreased. Finally, the E06-scFv prolonged life as measured over 15 months. Because the E06-scFv lacks the functional effects of an intact antibody other than the ability to bind OxPL and inhibit OxLDL uptake in macrophages, these data support a major proatherogenic role of OxLDL and demonstrate that OxPL are proinflammatory and proatherogenic, which E06 counteracts in vivo. These studies suggest that therapies inactivating OxPL may be beneficial for reducing generalized inflammation, including the progression of atherosclerosis, aortic stenosis and hepatic steatosis. A single-chain variable fragment of the antibody E06, which binds to the phosphocholine headgroup of oxidized phospholipids, blocks the uptake of oxidized low-density lipoprotein by macrophages, and reduces inflammation and atherosclerosis in hypercholesterolaemic mice.

Cholesterol crystals cleared A study in atherosclerosis-prone (apolipoprotein E-deficient) mice on a high cholesterol diet shows that small cholesterol crystals appear in the earliest stages of atherogenesis, and that these crystals can activate the NLRP3 inflammasome in phagocytes. This suggests that therapeutic strategies that reduce cholesterol crystal deposition or block the inflammasome pathway may have anti-atherosclerotic activity. During atherosclerosis, crystals of cholesterol accumulate in atherosclerotic plaques. But are they a consequence or a cause of the inflammation associated with the disease? Here it is shown that small cholesterol crystals appear early in the development of atherosclerosis, and that they act as an endogenous danger signal, causing inflammation by activating the NLRP3 inflammasome pathway. Cholesterol crystals thus seem to be an early cause, rather than a late consequence, of inflammation. The inflammatory nature of atherosclerosis is well established but the agent(s) that incite inflammation in the artery wall remain largely unknown. Germ-free animals are susceptible to atherosclerosis, suggesting that endogenous substances initiate the inflammation 1 . Mature atherosclerotic lesions contain macroscopic deposits of cholesterol crystals in the necrotic core, but their appearance late in atherogenesis had been thought to disqualify them as primary inflammatory stimuli. However, using a new microscopic technique, we revealed that minute cholesterol crystals are present in early diet-induced atherosclerotic lesions and that their appearance in mice coincides with the first appearance of inflammatory cells. Other crystalline substances can induce inflammation by stimulating the caspase-1-activating NLRP3 (NALP3 or cryopyrin) inflammasome 2 , 3 , which results in cleavage and secretion of interleukin (IL)-1 family cytokines. Here we show that cholesterol crystals activate the NLRP3 inflammasome in phagocytes in vitro in a process that involves phagolysosomal damage. Similarly, when injected intraperitoneally, cholesterol crystals induce acute inflammation, which is impaired in mice deficient in components of the NLRP3 inflammasome, cathepsin B, cathepsin L or IL-1 molecules. Moreover, when mice deficient in low-density lipoprotein receptor (LDLR) were bone-marrow transplanted with NLRP3-deficient, ASC (also known as PYCARD)-deficient or IL-1α/β-deficient bone marrow and fed on a high-cholesterol diet, they had markedly decreased early atherosclerosis and inflammasome-dependent IL-18 levels. Minimally modified LDL can lead to cholesterol crystallization concomitant with NLRP3 inflammasome priming and activation in macrophages. Although there is the possibility that oxidized LDL activates the NLRP3 inflammasome in vivo , our results demonstrate that crystalline cholesterol acts as an endogenous danger signal and its deposition in arteries or elsewhere is an early cause rather than a late consequence of inflammation. These findings provide new insights into the pathogenesis of atherosclerosis and indicate new potential molecular targets for the therapy of this disease.

BACKGROUND:Air pollution is associated with cardiovascular disease, and systemic inflammation may mediate this effect. We assessed associations between long- and short-term concentrations of air pollution and markers of inflammation, coagulation, and endothelial activation. METHODS:We studied participants from the Multi-Ethnic Study of Atherosclerosis from 2000 to 2012 with repeat measures of serum C-reactive protein (CRP), interleukin-6 (IL-6), fibrinogen, D-dimer, soluble E-selectin, and soluble Intercellular Adhesion Molecule-1. Annual average concentrations of ambient fine particulate matter (PM2.5), individual-level ambient PM2.5 (integrating indoor concentrations and time–location data), oxides of nitrogen (NOx), nitrogen dioxide (NO2), and black carbon were evaluated. Short-term concentrations of PM2.5 reflected the day of blood draw, day prior, and averages of prior 2-, 3-, 4-, and 5-day periods. Random-effects models were used for long-term exposures and fixed effects for short-term exposures. The sample size was between 9,000 and 10,000 observations for CRP, IL-6, fibrinogen, and D-dimer; approximately 2,100 for E-selectin; and 3,300 for soluble Intercellular Adhesion Molecule-1. RESULTS:After controlling for confounders, 5 µg/m increase in long-term ambient PM2.5 was associated with 6% higher IL-6 (95% confidence interval = 2%, 9%), and 40 parts per billion increase in long-term NOx was associated with 7% (95% confidence interval = 2%, 13%) higher level of D-dimer. PM2.5 measured at day of blood draw was associated with CRP, fibrinogen, and E-selectin. There were no other positive associations between blood markers and short- or long-term air pollution. CONCLUSIONS:These data are consistent with the hypothesis that long-term exposure to air pollution is related to some markers of inflammation and fibrinolysis.

Metabolomics studies hold promise for the discovery of pathways linked to disease processes. Cardiovascular disease (CVD) represents the leading cause of death and morbidity worldwide. Here we used a metabolomics approach to generate unbiased small-molecule metabolic profiles in plasma that predict risk for CVD. Three metabolites of the dietary lipid phosphatidylcholine—choline, trimethylamine N -oxide (TMAO) and betaine—were identified and then shown to predict risk for CVD in an independent large clinical cohort. Dietary supplementation of mice with choline, TMAO or betaine promoted upregulation of multiple macrophage scavenger receptors linked to atherosclerosis, and supplementation with choline or TMAO promoted atherosclerosis. Studies using germ-free mice confirmed a critical role for dietary choline and gut flora in TMAO production, augmented macrophage cholesterol accumulation and foam cell formation. Suppression of intestinal microflora in atherosclerosis-prone mice inhibited dietary-choline-enhanced atherosclerosis. Genetic variations controlling expression of flavin monooxygenases, an enzymatic source of TMAO, segregated with atherosclerosis in hyperlipidaemic mice. Discovery of a relationship between gut-flora-dependent metabolism of dietary phosphatidylcholine and CVD pathogenesis provides opportunities for the development of new diagnostic tests and therapeutic approaches for atherosclerotic heart disease. Heart disease is a gut issue Stanley Hazen and colleagues show that gut flora can influence cardiovascular disease by metabolizing a dietary phospholipid. A targeted metabolomics approach was used to identify plasma metabolites whose levels predict future risk for experiencing a non-fatal heart attack, stroke or death in subjects undergoing cardiac evaluation. Plasma levels of three metabolites of dietary phosphatidylcholine — choline, betaine and trimethylamine N -oxide (TMAO) — are associated with increased risk of cardiovascular disease. The gut flora is known to have a role in TMAO formation from choline. In addition, experiments in atherosclerosis-prone mice show that dietary choline enhances macrophage foam-cell formation and lesion formation — but not if the gut flora is depleted with antibiotics. This work suggests new diagnostic and therapeutic approaches for atherosclerotic heart disease. This paper shows that gut flora can influence cardiovascular disease, by metabolizing a dietary phospholipid. Using a metabolomics approach it is found that plasma levels of three metabolites of dietary phosphatidylcholine—choline, betaine and TMAO—are associated with increased risk of cardiovascular disease in humans. The gut flora is known to have a role in TMAO formation from choline, and this paper shows that dietary choline supplementation enhances macrophage foam cell formation and lesion formation in atherosclerosis-prone mice, but not if the gut flora are depleted with antibiotics.

Background Microplastics, widely present in the environment, are implicated in disease pathogenesis through oxidative stress and immune modulation. Prevailing research, primarily based on animal and cell studies, falls short in elucidating microplastics' impact on human cardiovascular health. This cross-sectional study detected blood microplastic concentrations in patients presenting with chest pain using pyrolysis–gas chromatography/mass spectrometry and evaluating inflammatory and immune markers through flow cytometry, to explore the potential effects of microplastic on acute coronary syndrome. Results The study included 101 participants, comprising 19 controls and 82 acute coronary syndrome cases. Notably, acute coronary syndrome patients exhibited elevated microplastic concentrations, with those suffering from acute myocardial infarction presenting higher loads compared to those with unstable angina. Furthermore, patients at intermediate to high risk of coronary artery disease displayed significantly higher microplastic accumulations than their low-risk counterparts. A significant relationship was observed between increased microplastic levels and enhanced IL-6 and IL-12p70 contents, alongside elevated B lymphocyte and natural killer cell counts. Conclusion These results suggest an association between microplastics and both vascular pathology complexity and immunoinflammatory response in acute coronary syndrome, underscoring the critical need for targeted research to delineate the mechanisms of this association. Highlights Blood microplastic levels escalate from angiographic patency, to angina patients, peaking in myocardial infarction patients. Microplastics in acute coronary syndrome patients are predominantly PE, followed by PVC, PS, and PP. Microplastics may induce immune cell-associated inflammatory responses in acute coronary syndrome patients. Graphical abstract

Purpose of ReviewImmune checkpoint inhibitors (ICIs) have improved the survival of several cancers. However, they may cause a wide range of immune-related adverse events (irAEs). While most irAEs are manageable with temporary cessation of ICI and immunosuppression, cardiovascular toxicity can be associated with high rates of morbidity and mortality. As ICIs evolve to include high-risk patients with preexisting cardiovascular risk factors and disease, the risk and relevance of ICI-associated cardiotoxicity may be even higher.Recent FindingsSeveral cardiovascular toxicities such as myocarditis, stress cardiomyopathy, and pericardial disease have been reported in association with ICIs. Recent findings also suggest an increased risk of atherosclerosis with ICI use. ICI-associated myocarditis usually occurs early after initiation and can be fulminant. A high index of suspicion is required for timely diagnosis. Prompt treatment with high-dose corticosteroids is shown to improve outcomes.SummaryAlthough the overall incidence is rare, ICI cardiotoxicity, particularly myocarditis, is associated with significant morbidity and mortality, making it a major therapy-limiting adverse event. Early recognition and prompt treatment with the cessation of ICI therapy and initiation of high-dose corticosteroids are crucial to improve outcomes. Cardio-oncologists will need to play an important role not just in the management of acute cardiotoxicity but also to reduce the risk of long-term sequelae.

Background/Aims: MicroRNA-9 (miR-9) is involved in inflammatory reaction in atherosclerosis; however, its function and regulatory mechanisms remain unclear. We aimed to uncover the exact roles of miR-9 and downstream signaling pathways using in vitro human atherosclerosis models. Methods: We used oxidized low-density lipoprotein (oxLDL)-stimulated human THP-1 derived macrophages, oxLDL-stimulated human primary peripheral blood monocytes and lipopolysaccharides (LPS) or Alum-stimulated human THP-1 derived macrophages as in vitro atherosclerosis inflammation models. Transient transfection of over-expression vectors, small interference RNAs (siRNAs) or antisense oligonucleotides was used to regulate intracellular protein or miR-9 levels. Cell responses and signal transduction were detected by multiple assays including Western blotting, enzyme-linked immunosorbent assay (ELISA) and luciferase reporter assay. Results: MiR-9 inhibited while anti-miR-9 antisense oligonucleotides induced interleukin-1 beta (IL-1β) and NLRP3 inflammasome activation in all in vitro models. Janus kinase 1 (JAK1) and matrix metalloproteinase 13 (MMP-13) were identified as the target genes of miR-9. In oxLDL-stimulated human THP-1 derived macrophages, knockdown of JAK1 by siRNA blocked the phosphorylation of signal transducer and activator of transcription 1 (STAT1) and mimicked the effects of miR-9. In the same model, JAK1 knockdown blocked the phosphorylation of NF-κB p65 in the nuclei and the phosphorylation of NF-κB IκBα in the cytoplasm. Conclusions: Our study demonstrated that miR-9 could inhibit activation of the NLRP3 inflammasome and attenuate atherosclerosis-related inflammation, likely through the JAK1/STAT1 signaling pathway. Therefore, miR-9 may serve as a potential therapeutic target for atherosclerosis.

Atherosclerotic cardiovascular disease has become the leading cause of death worldwide, and environmental pollutants are increasingly recognized as risk factors for atherosclerosis. Liver X receptors (LXRs) play a central role in atherosclerosis; however, LXR activity of organic pollutants and associated potential risk of atherosclerosis have not yet been characterized. This study aimed to explore whether LXR-antagonistic chemicals are present in indoor house dust and, if so, to characterize this activity in relation to changes in macrophages and cardiovascular disease indicators in an atherosclerosis mouse model. We used a -down assay and a nontarget high-resolution mass spectrometry method to screen house dust collected from Chinese homes for - and -antagonist activity. A chemical identified in this manner was assessed for its ability to induce cholesterol efflux and foam cell formation in RAW264.7 macrophages, to down-regulate the expression of two LXR-dependent genes, and , and finally to induce atherosclerotic lesions using an mouse model. We identified the flame retardants triphenyl phosphate (TPHP) and 2-ethylhexyl diphenyl phosphate (EHDPP) in house dust samples and demonstrated their ability to antagonize LXRs. The potency of TPHP was similar to that of the LXR-antagonist SR9238. TPHP could also inhibit cholesterol efflux and promote foam cell formation in RAW264.7 macrophages and mouse peritoneal macrophages and significantly promoted atherosclerotic lesion formation in the mouse model. We found LXR-antagonist chemicals in environmental samples of indoor dust from Chinese homes. One of the chemicals, TPHP, was able to promote the development of atherosclerotic lesions in the mouse model. These results highlight the need to assess the LXR-antagonist activities of pollutants in future environmental management programs. https://doi.org/10.1289/EHP5039.

The BCR/ABL1 inhibitor Nilotinib is increasingly used to treat patients with chronic myeloid leukemia (CML). Although otherwise well-tolerated, Nilotinib has been associated with the occurrence of progressive arterial occlusive disease (AOD). Our objective was to determine the exact frequency of AOD and examine in vitro and in vivo effects of Nilotinib and Imatinib on endothelial cells to explain AOD-development. In contrast to Imatinib, Nilotinib was found to upregulate pro-atherogenic adhesion-proteins (ICAM-1, E-selectin, VCAM-1) on human endothelial cells. Nilotinib also suppressed endothelial cell proliferation, migration and tube-formation and bound to a distinct set of target-kinases, relevant to angiogenesis and atherosclerosis, including angiopoietin receptor-1 TEK, ABL-2, JAK1 and MAP-kinases. Nilotinib and siRNA against ABL-2 also suppressed KDR expression. In addition, Nilotinib augmented atherosclerosis in ApoE−/− mice and blocked reperfusion and angiogenesis in a hindlimb-ischemia model of arterial occlusion, whereas Imatinib showed no comparable effects. Clinically overt AOD-events were found to accumulate over time in Nilotinib-treated patients. After a median observation-time of 2.0 years, the AOD-frequency was higher in these patients (29.4%) compared to risk factor- and age-matched controls (<5%). Together, Nilotinib exerts direct pro-atherogenic and anti-angiogenic effects on vascular endothelial cells, which may contribute to development of AOD in patients with CML.