Atherosclerotic Plaque Destabilization Research Articles

Destabilization of Atherosclerotic Plaque by Bilirubin Deficiency.

The rupture of atherosclerotic plaque contributes significantly to cardiovascular disease. Plasma concentrations of bilirubin-a byproduct of heme catabolism-inversely associate with risk of cardiovascular disease, although the link between bilirubin and atherosclerosis remains unclear. To assess the role of bilirubin in atherosclerotic plaque stability, we crossed Bvra-/- with Apoe-/- mice and used the tandem stenosis model of plaque instability. Human coronary arteries were obtained from heart transplant recipients. Analysis of bile pigments, heme metabolism, and proteomics were performed by liquid chromatography tandem mass spectrometry. MPO (myeloperoxidase) activity was determined by in vivo molecular magnetic resonance imaging, liquid chromatography tandem mass spectrometry analysis, and immunohistochemical determination of chlorotyrosine. Systemic oxidative stress was evaluated by plasma concentrations of lipid hydroperoxides and the redox status of circulating Prx2 (peroxiredoxin 2), whereas arterial function was assessed by wire myography. Atherosclerosis and arterial remodeling were quantified by morphometry and plaque stability by fibrous cap thickness, lipid accumulation, infiltration of inflammatory cells, and the presence of intraplaque hemorrhage. Compared with Bvra+/+Apoe-/- tandem stenosis littermates, Bvra-/-Apoe-/- tandem stenosis mice were deficient in bilirubin, showed signs of increased systemic oxidative stress, endothelial dysfunction, as well as hyperlipidemia, and had a higher atherosclerotic plaque burden. Heme metabolism was increased in unstable compared with stable plaque of both Bvra+/+Apoe-/- and Bvra-/-Apoe-/- tandem stenosis mice and in human coronary plaques. In mice, Bvra deletion selectively destabilized unstable plaque, characterized by positive arterial remodeling and increased cap thinning, intraplaque hemorrhage, infiltration of neutrophils, and MPO activity. Proteomic analysis confirmed Bvra deletion enhanced extracellular matrix degradation, recruitment and activation of neutrophils, and associated oxidative stress in unstable plaque. Bilirubin deficiency, resulting from global Bvra deletion, generates a proatherogenic phenotype and selectively enhances neutrophil-mediated inflammation and destabilization of unstable plaque, thereby providing a link between bilirubin and cardiovascular disease risk.

Meet the First Authors.

Meet the First Authors.

Blockade of the BLT1-LTB4 axis does not affect mast cell migration towards advanced atherosclerotic lesions in LDLr−/− mice

Mast cells have been associated with the progression and destabilization of advanced atherosclerotic plaques. Reducing intraplaque mast cell accumulation upon atherosclerosis progression could be a potent therapeutic strategy to limit plaque destabilization. Leukotriene B4 (LTB4) has been reported to induce mast cell chemotaxis in vitro. Here, we examined whether antagonism of the LTB4-receptor BLT1 could inhibit mast cell accumulation in advanced atherosclerosis. Expression of genes involved in LTB4 biosynthesis was determined by single-cell RNA sequencing of human atherosclerotic plaques. Subsequently, Western-type diet fed LDLr−/− mice with pre-existing atherosclerosis were treated with the BLT1-antagonist CP105,696 or vehicle control three times per week by oral gavage. In the spleen, a significant reduction in CD11b+ myeloid cells was observed, including Ly6Clo and Ly6Chi monocytes as well as dendritic cells. However, atherosclerotic plaque size, collagen and macrophage content in the aortic root remained unaltered upon treatment. Finally, BLT1 antagonism did not affect mast cell numbers in the aortic root. Here, we show that human intraplaque leukocytes may be a source of locally produced LTB4. However, BLT1-antagonism during atherosclerosis progression does not affect either local mast cell accumulation or plaque size, suggesting that other mechanisms participate in mast cell accumulation during atherosclerosis progression.

KOUNIS SYNDROME, THE ALLERGIC HEART ATTACK

<h3>Introduction</h3> Seldom do allergic reactions progress to involve the heart. Kounis Syndrome is the occurrence of acute coronary syndrome associated with conditions of mast cell activation such as allergy hypersensitivities (1). Here, we describe a case in which an allergic reaction to injected Lidocaine and Kenalog leads to myocardial infarction. <h3>Case Description</h3> A 67-year-old female with cardiac risk factors and osteoarthritis underwent injection of her right ankle with Lidocaine and Kenalog. She developed diffuse erythematous rash with symptoms of lightheadedness, altered mentation, and chest discomfort. Upon admission, she received epinephrine. Electrocardiogram (EKG) demonstrated ST-segment elevation in inferior leads II, III, and aVF. Labs revealed serum tryptase level of 74.8 ug/L. The patient received intravenous (IV) Norepinephrine, IV diphenhydramine, IV Famotidine, IV methylprednisolone, Aspirin, and continuous IV heparin for emergent coronary angiography. The distal right coronary artery revealed occlusive thrombus burden, causing 95% stenosis. Percutaneous coronary intervention was performed with drug-eluting stent placement. Her symptoms resolved, and she was referred to an outpatient allergist. <h3>Discussion</h3> This case illustrates the type II variant of Kounis Syndrome in which inflammatory mediators from an allergic reaction induce atherosclerotic plaque destabilization and rupture in underlying coronary artery disease (CAD). Cardiovascular manifestations associated with allergic conditions are more common than initially perceived, suggesting a causal relationship between allergies and heart disease. This remains underdiagnosed by clinicians in practice (1,2). Biomarkers in allergies, such as serum tryptase, may provide a potential marker of CAD. Novel medications that stabilize mast cells and reduce inflammation known to control allergies may ultimately reduce cardiovascular events (4).

Tissue oxygenation stabilizes neovessels and mitigates hemorrhages in human atherosclerosis-induced angiogenesis.

Progression of atherosclerosis is associated with a maladaptive form of angiogenesis which contributes to intraplaque hemorrhage and plaque disruption. Hypoxia has been implicated in mechanisms of angiogenic neovessel fragility and atherosclerotic plaque destabilization. We used ex vivo and in vivo models to characterize the effect of oxygen (O2) on the formation, stability and tendency to bleed of human plaque-induced neovessels. Plaque explants potently stimulated the ex vivo angiogenic response of rat aortic rings at atmospheric O2 levels. Severe hypoxia (1% O2) inhibited plaque-induced angiogenesis and pericyte recruitment causing neovessel breakdown, whereas increasing O2 levels dose dependently enhanced pericyte numbers and neovessel stability. Plaque fragments implanted subcutaneously with or without aortic rings in SCID mice stimulated the host angiogenic response with plaques causing minimal or no hemorrhages and plaques co-implanted with aortic rings causing marked hemorrhages. Plaque/aortic ring-induced hemorrhages were reduced in mice exposed to moderate hyperoxia (50% O2). Hyperoxia downregulated expression of the hypoxia-sensitive genes Ca9, Ca12 and VegfA and increased influx into implants of mesenchymal cells reactive for the pericyte marker NG2. In both ex vivo and in vivo models, O2 promoted expression of vasostabilizing genes required for pericyte recruitment (Angpt1, Pdgfb), basement membrane assembly (Col4A1), and tight junction formation (Cldn5 and/or Ocln). Our results suggest that formation of neovessels that are stable, pericyte-coated, and resistant to bleeding requires adequate tissue oxygenation. Understanding the mechanisms by which O2 stabilizes neovessels and mitigates neovessel bleeding may lead to new therapies for the prevention of atherosclerosis complications.

Abstract P2095: Role Of Intraplaque Lipids In Atherosclerotic Plaque Vulnerability

Background: Hyperlipidemia plays a pivotal role in the pathogenesis of diabetes, atherosclerosis, and cardiovascular diseases. Specific lipids of atherosclerotic plaques are potentially one of the local factors which render them susceptible to rupture. Their underlying unresolved inflammation and oxidative stress contribute to the transition from stable to unstable plaques. Therefore, we aimed to identify, characterize, and compare the intraplaque lipids composition among diabetic and non-diabetic patients and to ascertain their role in inflammation, and atherosclerotic plaque destabilization and rupture. Methods: Approved by the IRB, University of Arizona, Tucson Lipids were analyzed by liquid chromatography-mass spectrometry (LC-MS) from 40 surgically removed endarterectomy specimens that include Asymptomatic &amp; Non-diabetic (n=13), Symptomatic &amp; Non-diabetic (n=17), Asymptomatic &amp; Diabetic (n=5) iv. Symptomatic &amp; Diabetic (n=5) patients. Seventy nine lipid species from the main lipid classes phosphatidylcholine (PC), phosphatidylserine (PS), phosphatidylethanolamine (PE), phosphatidylinositol (PI), cholesteryl ester (CE) phosphatidylglycerol (PG), sphingomyelin (SM), and ceramide (Cer) were included in this lipidomic profiling. Results: LC-MS data analysis identified a significant difference (p&lt;0.05) in 2 individual lipid species – a long chain polyunsaturated PC(40:7) and SM(18:1) between diabetic and non-diabetic (Table:1). A total of 23 lipid species were significantly (p&lt;0.05 to p&lt;0.005) differentially present between symptomatic and asymptomatic samples. Symptomatic diabetic and nondiabetic samples showed a significant (p&lt;0.05 to p&lt;0.005) difference in 13 lipids belonging to PC, SM and PE. Our studies also showed a higher peroxidation of intraplaque lipid from diabetic patients compared to non-diabetics, and a significant increase in reactive oxygen species (ROS) production in human coronary artery smooth muscle cells treated with lipids from diabetic plaques. Conclusions: This exploratory analysis showed distinct patterns of intraplaque lipid composition. Identification of these high-risk plaque lipid biomarkers will help to delineate the cellular and molecular mechanism responsible for stable to vulnerable plaques transition.

Single-cell and spatially resolved transcriptome analysis reveals cellular heterogeneities and novel regulators of atherosclerotic plaque destabilization

Background and Aims: Cardiovascular diseases, including atherosclerosis, are the major cause of death in western societies, still molecular mechanisms of plaque destabilization remain unclear. Long non-coding RNAs (lncRNAs) are one example of novel molecular modulators, as their expression is highly cell-type specific.

Serum matrix metalloproteinase type 9 in patients with coronary heart disease

BACKGROUND: The study sends to quantify type 9 matrix metalloproteinase in serum in patients with coronary heart disease, since this enzyme is able to provoke an immunoinflammatory process leading to destabilization of atherosclerotic plaque, the development of unstable angina and acute coronary syndrome.&#x0D; AIM: Is to conduct a comparative analysis of the quantitative content of MMR-9 in serum in patients with coronary heart disease (CHD) with a different course of angina and atherosclerosis and in relatively healthy individuals.&#x0D; MATERIALS AND METHODS: Blood serum samples of 66 CHD patients were examined. All patients based on clinical examination were divided into 3 groups, depending on the severity of the disease. Quantitative MMR-9 analysis was performed using the Thermo Fisher ELISA kits (BMS2016-2). Determination of the amount of MMR-9 in serum was recorded in the ELX 800 ELISA reader plate. Data processing was carried out using Statistica 6.0 statistical analysis (StatSof, USA). The results were presented as means and mean errors.&#x0D; RESULTS: The obtained results indicate a significant decrease in the concentration of MMR-9 in the serum of patients with an unstable course of the disease compared to the control group (relatively healthy people). This is probably due to the effect on the content and activity of its MMR-9 inhibitor TIMP-1. Further studies will investigate whether MMR-9 can be considered as a marker of destabilization of atherosclerotic plaque and act as an independent predictor of acute clinical complications in patients with cardiovascular pathology.&#x0D; CONCLUSIONS: The study made it possible to establish a significant decrease in the concentration of MMR-9 in the serum of patients with an unstable course of atherosclerosis compared to the control group (relatively healthy people). In addition, in patients with an unstable course of atherosclerosis, a tendency to reduce the concentration of this enzyme compared to persons with stable atherosclerosis was revealed.

The Effect of Estrogen and Testosterone on Cholesterol Crystallization

Lead Author's Financial Disclosures Nothing to disclose. Study Funding None. Background/Synopsis Cholesterol crystallization has been implicated in the destabilization of atherosclerotic plaque leading to rupture and cardiovascular events. This is based on volume expansion of the plaque's lipid rich necrotic core by sharp tipped cholesterol crystals. Estrogens have been recognized to provide protection form cardiovascular events in pre-menopausal women compared to their male counterparts. Objective/Purpose In this study we evaluated the role of estrogen and testosterone on cholesterol crystallization and volume expansion as a risk for plaque destabilization. Methods Graded concentrations of estradiol or testosterone (13 micrograms, 130 micrograms, and 1.3 milligrams) were mixed with cholesterol powder (3 g + 1 ml H2O) and melted in graduated cylinders and allowed to crystallize at room temperature (22 Celsius). Differences in volume expansion (delta VE) between liquid and crystalline phases were measured and compared to control tubes with H2O alone. Results Increasing concentration of estrogen was associated with a statistically significant reduction in cholesterol expansion with crystallization (p<0.01) while increasing concentration of testosterone was not associated with reduction in cholesterol expansion (p=0.52) (Figure). Conclusions Estrogen demonstrated a decreased cholesterol volume expansion with crystallization while testosterone did not. These findings are consistent with clinical observations that support the protective effects of estrogen with regards to acute cardiovascular events and an increased risk associated with testosterone. Nothing to disclose.

The E3 Ubiquitin Ligase Peli1 Deficiency Promotes Atherosclerosis Progression

Background: Atherosclerosis is a chronic inflammatory vascular disease and the main cause of death and morbidity. Emerging evidence suggests that ubiquitination plays an important role in the pathogenesis of atherosclerosis including control of vascular inflammation, vascular smooth muscle cell (VSMC) function and atherosclerotic plaque stability. Peli1 a type of E3 ubiquitin ligase has emerged as a critical regulator of innate and adaptive immunity, however, its role in atherosclerosis remains to be elucidated. Methods: Apoe−/− mice and Peli1-deficient Apoe−/− Peli1−/− mice were subject to high cholesterol diet. Post sacrifice, serum was collected, and atherosclerotic plaque size and parameters of atherosclerotic plaque stability were evaluated. Immunoprofiling and foam cell quantification were performed. Results: Peli1 deficiency does not affect atherosclerosis lesion burden and cholesterol levels, but promotes VSMCs foam cells formation, necrotic core expansion, collagen, and fibrous cap reduction. Apoe−/− Peli1−/− mice exhibit a storm of inflammatory cytokines, expansion of Th1, Th1, Th17, and Tfh cells, a decrease in regulatory T and B cells and induction of pro-atherogenic serum level of IgG2a and IgE. Conclusions: In the present study, we uncover a crucial role for Peli1 in atherosclerosis as an important regulator of inflammation and VSMCs phenotypic modulation and subsequently atherosclerotic plaque destabilization.

Gasdermin D Deficiency Limits the Transition of Atherosclerotic Plaques to an Inflammatory Phenotype in ApoE Knock-Out Mice.

Gasdermin D (GSDMD) is the key executor of pyroptotic cell death. Recent studies suggest that GSDMD-mediated pyroptosis is involved in atherosclerotic plaque destabilization. We report that cleaved GSDMD is expressed in macrophage- and smooth muscle cell-rich areas of human plaques. To determine the effects of GSDMD deficiency on atherogenesis, ApoE−/− Gsdmd−/− (n = 16) and ApoE−/− Gsdmd+/+ (n = 18) mice were fed a western-type diet for 16 weeks. Plaque initiation and formation of stable proximal aortic plaques were not altered. However, plaques in the brachiocephalic artery (representing more advanced lesions compared to aortic plaques) of ApoE−/− Gsdmd−/− mice were significantly smaller (115 ± 18 vs. 186 ± 16 × 103 µm2, p = 0.006) and showed features of increased stability, such as decreased necrotic core area (19 ± 4 vs. 37 ± 7 × 103 µm2, p = 0.03) and increased αSMA/MAC3 ratio (1.6 ± 0.3 vs. 0.7 ± 0.1, p = 0.01), which was also observed in proximal aortic plaques. Interestingly, a significant increase in TUNEL positive cells was observed in brachiocephalic artery plaques from ApoE−/− Gsdmd−/− mice (141 ± 25 vs. 62 ± 8 cells/mm2, p = 0.005), indicating a switch to apoptosis. This switch from pyroptosis to apoptosis was also observed in vitro in Gsdmd−/− macrophages. In conclusion, targeting GSDMD appears to be a promising approach for limiting the transition to an inflammatory, vulnerable plaque phenotype.

Plasma Concentrations of Cytokines in Patients with Combined Hyperlipidemia and Atherosclerotic Plaque before Treatment Initiation-A Pilot Study.

Background and Objectives: The formation and destabilization of atherosclerotic plaques is a complex process involving several proteins and cytokines. Interleukin 6 (IL-6), interleukin 18 (IL-18), and tumor necrosis factor (TNF-α) are examples of such cytokines. The goal of our research is to compare the concentrations of the above-mentioned indicators in the plasma of patients with verified high-risk atherosclerotic plaque to the plasma levels of healthy people before lipid lowering therapy. Materials and Methods: Patients with dyslipidemia who had the presence of unstable atherosclerotic plaque verified by ultrasonography were included in the study. The concentrations of IL-6, IL-18 and TNF-α in the plasma of these people were determined and compared with the concentrations of these cytokines in the plasma of the control group. Results: Levels of lipid panel, IL-6 and IL-18 were significantly lower in the group of healthy people than in the study group. Conclusions: The concentrations of IL-6 and IL-18 in the plasma of patients with ruptured plaque are higher than in the plasma of healthy people, suggesting that these cytokines as a panel might be used as new indicators of the presence of unstable atherosclerotic plaque.

Major Vault Protein Prevents Atherosclerotic Plaque Destabilization by Suppressing Macrophage ASK1-JNK Signaling.

Macrophages are implicated in atherosclerotic plaque instability by inflammation and degradation of extracellular matrix. However, the regulatory mechanisms driving these macrophage-associated processes are not well understood. Here, we aimed to identify the plaque destabilization-associated cytokines and signaling pathways in macrophages. The atherosclerotic models of myeloid-specific MVP (major vault protein) knockout mice and control mice were generated. Atherosclerotic instability, macrophage inflammatory signaling, and active cytokines released by macrophages were examined in vivo and in vitro by using cellular and molecular biological approaches. MVP deficiency in myeloid cells exacerbated murine plaque instability by increasing production of both MMP (matrix metallopeptidase)-9 and proinflammatory cytokines in artery wall. Mechanistically, expression of MMP-9 was mediated via ASK1 (apoptosis signal-regulating kinase 1)-MKK-4 (mitogen-activated protein kinase kinase 4)-JNK (c-Jun N-terminal kinase) signaling in macrophages. MVP and its α-helical domain could bind with ASK1 and inhibit its dimerization and phosphorylation. A 62 amino acid peptide (MVP-[686-747]) in the α-helical domain of MVP showed a crucial role in preventing macrophage MMP-9 production and plaque instability. MVP may act as an inhibitor for ASK1-JNK signaling-mediated MMP-9 production in macrophages and, thereby, attenuate unstable plaque formation. Our findings suggest that suppression of macrophage ASK1-JNK signaling may be a useful strategy antagonizing atherosclerotic diseases.

IDF21-0426 Carbamylated LDL and soluble LOX-1 – potential serum biomarkers for coronary artery disease in type 2 diabetes mellitus

Background: Carbamylated low-density lipoprotein (cLDL) is the most abundant modified LDL isoform in human blood, but it has been investigated only in the context of chronic kidney disease since uremia provides a favourable chemical environment for this posttranslational modification. However, it has been discovered that the proinflammatory enzyme myeloperoxidase catalyses an alternative urea-independent mechanism of carbamylation. Most of the proatherogenic properties of cLDL are mediated by the scavenger lectin-like oxidized LDL receptor-1 (LOX-1). LOX-1 has been delineated as a critical player in vascular inflammation and in atherosclerotic plaque formation, destabilization, erosion and rupture. The cLDL-LOX-1 interaction triggers prooxidative and proinflammatory responses. Moreover, LOX-1 has also been identified as a receptor for C-reactive protein (CRP), a classic acute-phase reactant widely used in the clinical practice as a cardiovascular risk biomarker. The soluble form of LOX-1 (sLOX-1) reflects the expression of the membrane receptor and it has recently been suggested as a biomarker of vascular diseases. It is well-established that type 2 diabetes mellitus (T2DM) is a prominent risk factor for coronary artery disease (CAD) and inflammation is involved in the pathogenesis of both T2DM and atherosclerosis. However, the possible role and relationships between cLDL, sLOX-1 and CRP in T2DM with and without CAD have not been investigated yet. Aim: To explore the possible role of cLDL and sLOX-1 as potential biomarkers for CAD in T2DM patients and to evaluate the correlations between serum cLDL, sLOX-1 and high-sensitivity-CRP (hs-CRP). Method: The serum levels of cLDL, sLOX-1 and hs-CRP were measured by ELISA in 44 heathy controls, 67 patients with uncomplicated T2DM and 36 diabetic subjects complicated by CAD but without renal impairments. Results: Patients with uncomplicated T2DM had significantly higher serum levels of both cLDL and hs-CRP than the healthy controls, but lower in comparison to T2DM + CAD subjects. In contrast, there was no significant difference in sLOX-1 concentrations between T2DM patient and the healthy volunteers, but T2DM + CAD cohort had higher serum levels of sLOX-1 compared both to the control and uncomplicated T2DM groups. The receiver-operating characteristic analysis showed that cLDL and sLOX-1 had a significant potential to identify CAD among the diabetic patients with diagnostic sensitivity and specificity similar to those of hs-CRP. Elevated serum levels of cLDL and sLOX-1 were associated with a higher risk of CAD development among T2DM subjects (OR 4.07; 95% CI: 1.71 – 9.69, p = 0.001 and OR 2.82; 95% CI: 1.22 – 6.57, p = 0.014, respectively). Furthermore, the level of cLDL correlated positively and significantly with hs-CRP(r = 0.345, p = 0.039) and tended to correlate positively with sLOX-1 (r = 0.317, p = 0.059) only in T2DM + CAD subjects. Discussion: In conclusion, a positive feedback might exist between cLDL, CRP and LOX-1 and the interplay between them might be involved in the development of CAD in diabetic patients. The present study also elucidates the potential of cLDL and sLOX-1 as biomarkers for the diagnosis and risk assessment of CAD among T2DM population.

Особенности течения острого коронарного синдрома у пациентов с новой коронавирусной инфекцией COVID-19

INTRODUCTION: Coronary heart disease (CHD) is an important medical and social problem. It occupies one of the leading positions in the structure of morbidity, temporary and permanent disability and mortality. The peculiarities of the course of acute coronary syndrome (ACS) in patients with new coronavirus infection COVID-19 are of great clinical interest. Studies have shown that the effect of COVID-19 on the cardiovascular system consists not only the in direct cardiotoxic effect of the virus, but also in myocardial damage due to hemodynamic disorders, systemic hypoxia, destabilization of atherosclerotic plaques due to endothelial dysfunction, increased myocardial oxygen demand as a response to systemic inflammation, coagulopathy and others. An important role is played by the involvement of the vascular endothelium in the pathological process. There is extensive evidence of SARS-CoV-2 directly infecting endothelial cells because of the high level of expression of angiotensin-converting enzyme 2. The combination of ACS and new coronavirus infection is a frequent event in both infectious disease units and specialized coronary centers. However, many questions of pathogenesis, clinical presentation, diagnosis and management tactics of such patients are not clear enough. There are data on the manifestation of cardiovascular diseases against the background COVID-19. The difficulty is that clinical presentation of acute coronary syndrome in COVID-19 patients can be masked by peculiarities of the course of infectious disease itself. CONCLUSION: Differential diagnosis of COVID-19 and ACS has also become a problem for clinicians due to the fact that symptoms of chest pain or chest tightness are common in patients with new coronavirus infection. Myocardial damage in coronavirus infection can impair interpretation of the results of some clinical diagnostic tools. A complex disputable problem is assessment of prognosis in ACS combined with COVID-19. Most patients with COVID-19 have disorders of the clotting system, the severity of which determines the probability of adverse outcomes, above all, the risk of death.

Interaction between bacteria and cholesterol crystals: Implications for endocarditis and atherosclerosis.

BackgroundThe interaction between pathogenic bacteria and cholesterol crystals (CCs) has not been investigated. However, CCs are found extensively in atherosclerotic plaques and sclerotic cardiac valves. Interactions between pathogenic bacteria and CCs could provide insights into destabilization of atherosclerotic plaques and bacterial adhesion to cardiac valves.MethodsStaphylococcus aureus and Pseudomonas aeruginosa were used to assess in vitro bacterial adhesion to CCs and proliferation in the presence of CCs compared to plastic microspheres and glass shards as controls. Ex vivo studies evaluated bacterial adhesion to atherosclerotic rabbit arteries compared to normal arteries and human atherosclerotic carotid plaques compared to normal carotid arteries. Scanning electron microscopy (SEM) was used to visualize bacterial adhesion to CCs and confocal microscopy was used to detect cholesterol binding to bacteria grown in the presence or absence of CCs.ResultsIn vitro, S. aureus and P. aeruginosa displayed significantly greater adhesion, 36% (p<0.0001) and 89% (p<0.0001), respectively, and growth upon exposure to CCs compared to microspheres or glass shards. Rabbit and human atherosclerotic arteries contained significantly greater bacterial burdens compared to controls (4× (p<0.0004); 3× (p<0.019), respectively. SEM demonstrated that bacteria adhered and appeared to degrade CCs. Consistent with this, confocal microscopy indicated increased cholesterol bound to the bacterial cells.ConclusionsThis study is the first to demonstrate an interaction between bacteria and CCs showing that bacteria dissolve and bind to CCs. This interaction helps to elucidate adhesion of bacteria to sclerotic valves and atherosclerotic plaques that may contribute to endocarditis and plaque destabilization.

The role of the mineralocorticoid receptor in immune cells in cardiovascular disease.

Chronic low-grade inflammation and immune cell activation are important mechanisms in the pathophysiology of cardiovascular disease (CVD). Therefore, targeted immunosuppression is a promising novel therapy to reduce cardiovascular risk. In this review, we identify the mineralocorticoid receptor (MR) on immune cells as a potential target to modulate inflammation. The MR is present in almost all cells of the cardiovascular system, including immune cells. Activation of the MRs in innate and adaptive immune cells induces inflammation which can contribute to CVD, by inducing endothelial dysfunction and hypertension. Moreover, it accelerates atherosclerotic plaque formation and destabilization and impairs tissue regeneration after ischaemic events. Identifying the molecular targets for these non-renal actions of the MR provides promising novel cardiovascular drug targets for mineralocorticoid receptor antagonists (MRAs), which are currently mainly applied in hypertension and heart failure. LINKED ARTICLES: This article is part of a themed issue on Emerging Fields for Therapeutic Targeting of the Aldosterone-Mineralocorticoid Receptor Signaling Pathway. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v179.13/issuetoc.

Unexpected Relationships: Periodontal Diseases: Atherosclerosis-Plaque Destabilization? From the Teeth to a Coronary Event.

Simple SummaryPeriodontal disease and atherosclerotic cardiovascular disease are very common around the world. Coronary artery disease is the leading cause of death. The main factor involved in the pathogenesis of atherosclerosis is inflammation. Therefore, a number of studies have indicated that periodontal disease (causes chronic inflammation) is a risk factor for the progression of atherosclerosis. The presence of periodontal pathogens has been found in human atherosclerotic plaques. A number of pathomechanisms have been demonstrated, thanks to which periodontal pathogens, especially Porphyromonas gingivalis, can directly increase the progression of atherosclerosis and the risk of cardiovascular disease. Observational studies found that patients with periodontal disease were at higher risk of developing atherosclerotic cardiovascular disease. Moreover, periodontal treatment leads to a reduction in cardiovascular risk therefore taking care of oral hygiene should be an important cardiovascular disease preventive measure.Atherosclerotic cardiovascular disease (ASCVD) and periodontal disease (PD) are global health problems. High frequency of ASCVD is associated with the spread of many risk factors, including poor diet, sedentary lifestyle, diabetes, hyperlipidemia, obesity, smoking, hypertension, chronic kidney disease, hypertension, hyperhomocysteinemia, hyperuricemia, excessive stress, virus infection, genetic predisposition, etc. The pathogenesis of ASCVD is complex, while inflammation plays an important role. PD is a chronic, multifactorial inflammatory disease caused by dysbiosis of the oral microbiota, causing the progressive destruction of the bone and periodontal tissues surrounding the teeth. The main etiological factor of PD is the bacteria, which are capable of activating the immune response of the host inducing an inflammatory response. PD is associated with a mixed microbiota, with the evident predominance of anaerobic bacteria and microaerophilic. The “red complex” is an aggregate of three oral bacteria: Tannerella forsythia Treponema denticola and Porphyromonas gingivalis responsible for severe clinical manifestation of PD. ASCVD and PD share a number of risk factors, and it is difficult to establish a causal relationship between these diseases. The influence of PD on ASCVD should be treated as a factor increasing the risk of atherosclerotic plaque destabilization and cardiovascular events. The results of observational studies indicate that PD significantly increases the risk of ASCVD. In interventional studies, PD treatment was found to have a beneficial effect in the prevention and control of ASCVD. This comprehensive review summarizes the current knowledge of the relationship between PD and ASCVD.

Downregulation of TIGIT Expression in FOXP3+Regulatory T Cells in Acute Coronary Syndrome.

ObjectiveLittle is currently known on the role of T-cell immunoglobulin and ITIM domain (TIGIT) expression in Foxp3+ regulatory T cells (TIGIT+Tregs) in acute coronary syndrome (ACS) patients. The aim of this study was to investigate the role and alterations of TIGIT+Tregs in ACS patients.MethodsWe enrolled 117 subjects, including 61 ACS patients, 26 chronic coronary syndrome (CCS) patients, and 30 control subjects without coronary artery disease. The quantification of TIGIT+Tregs was determined by flow cytometry; serum interleukin-6 (IL-6) and transforming growth factor-β (TGF-β) were also measured.ResultsTIGIT+Tregs expression was significantly lower in ACS patients compared with CCS and control patients (P<0.05). The expression of TIGIT+Tregs was comparable in patients with and without traditional risk factors (P>0.05). Logistic regression analysis revealed that TIGIT+Tregs levels are independent predictors of ACS (P<0.01). Receiver-operating characteristic (ROC) curve analysis showed the expression levels of TIGIT+Tregs had a discriminative power for ACS (P<0.01). IL-6 levels were increased (P<0.01), while TGF-β was decreased in ACS patients compared with CCS and control patients (P<0.01). Meanwhile, an inverse correlation between IL-6 and TIGIT+Tregs was observed (P<0.01), while a positive correlation between TGF-β and TIGIT+Tregs was found (P<0.05).ConclusionTIGIT+Tregs levels are significantly reduced in ACS, accompanied by upregulated IL-6 and downregulated TGF-β expression. The downregulated TIGIT+Tregs are independent predictors of ACS. These findings suggest that TIGIT+Tregs may have an anti-inflammatory and protective effect on ACS, and its decreased expression may be associated with atherosclerotic plaque destabilization.

Single-Cell RNA-Seq Reveals a Crosstalk between Hyaluronan Receptor LYVE-1-Expressing Macrophages and Vascular Smooth Muscle Cells.

Background: Atherosclerosis is a chronic inflammatory disease where macrophages participate in the progression of the disease. However, the role of resident-like macrophages (res-like) in the atherosclerotic aorta is not completely understood. Methods: A single-cell RNA sequencing analysis of CD45+ leukocytes in the atherosclerotic aorta of apolipoprotein E–deficient (Apoe−/−) mice on a normal cholesterol diet (NCD) or a high cholesterol diet (HCD), respecting the side-to-specific predisposition to atherosclerosis, was performed. A population of res-like macrophages expressing hyaluronan receptor LYVE-1 was investigated via flow cytometry, co-culture experiments, and immunofluorescence in human atherosclerotic plaques from carotid artery disease patients (CAD). Results: We identified 12 principal leukocyte clusters with distinct atherosclerosis disease-relevant gene expression signatures. LYVE-1+ res-like macrophages, expressing a high level of CC motif chemokine ligand 24 (CCL24, eotaxin-2), expanded under hypercholesteremia in Apoe−/− mice and promoted VSMC phenotypic modulation to osteoblast/chondrocyte-like cells, ex vivo, in a CCL24-dependent manner. Moreover, the abundance of LYVE-1+CCL24+ macrophages and elevated systemic levels of CCL24 were associated with vascular calcification and CAD events. Conclusions: LYVE-1 res-like macrophages, via the secretion of CCL24, promote the transdifferentiation of VSMC to osteogenic-like cells with a possible role in vascular calcification and likely a detrimental role in atherosclerotic plaque destabilization.