Unstable Atherosclerotic Plaques Research Articles

Adipocytokine levels in patients with atherosclerosis and high triglyceride – glucose index

Aim. To study the levels of adipocytokines and their associations with stable and unstable atherosclerotic plaques in patients with a high triglyceride – glucose (TyG) index.Materials and methods. The study included 109 men aged 38–79 years (mean age 62.28 ± 8.19 years) with atherosclerosis hospitalized for coronary artery bypass grafting (CABG). After microscopy of the intima – media layer, the type of atherosclerotic plaque was determined: stable / unstable. The TyG index ≥ 4.49 was considered as high. Fifty-eight (60%) men had stable plaques in the CA (28 (56%) of them had TyG ≥ 4.49); 39 (40%) men had unstable plaques in the CA (15 (39%) had TyG ≥ 4.49). Blood adipocytokine level was studied using the multiplex assay and the Human Metabolic Hormone Panel V3.Results. The final analysis included 97 patients. The level of glucose-dependent insulinotropic polypeptide (GIP) was 1.53 times greater in patients with TyG ≥ 4.49 (34.16 [18.71; 54.98] vs. 22.34 [15.02; 34.77], p = 0.004). In patients with TyG < 4.49, the adipsin level was 1.2 times higher in patients with unstable plaques than in patients with stable ones. In patients with stable plaques and TyG ≥ 4.49, the GIP level was 1.88 times higher than in patients with TyG < 4.49 (42.13 [25.34; 68.95] vs. 22.39 [17.00; 28.60], p = 0.003). In patients with unstable plaques and TyG ≥ 4.49, the level of peptide tyrosine – tyrosine (PYY) was 1.46 times greater than in patients with TyG < 4.49 (46.14 [30.49; 70.66] vs. 31.53 [24.71; 43.01], p = 0.048).Conclusion. Men with atherosclerosis and TyG ≥ 4.49 had higher blood levels of GIP and PYY. Blood adipsin levels were higher in patients with unstable plaques without insulin resistance.

Involvement of interferon-gamma and tumor necrosis factor-alpha in the formation of unstable atherosclerotic plaque

Research on the role of various interleukins in atherosclerosis has shown that pro-inflammatory cytokines contribute to disease progression and destabilization of atherosclerotic plaques. The review presents the latest data from the scientific literature and the study’s own findings on the effects of pro-inflammatory cytokines INF-γ and TNF-α on the formation of unstable atherosclerotic lesions. It has been shown that the deterioration of the unstable plaque cap strength and its destruction can be associated with an increase in concentration, activation and action of powerful pro-inflammatory cytokines INF-γ and TNF-α in the vascular wall.

Biomolecules of Adipose Tissue in Atherosclerotic Plaques of Men With Coronary Atherosclerosis.

To study metabolic molecules (adiponectin, adipsin, resistin, glucagon-like peptide-1 (GLP-1), glucagon, secretin) of adipose tissue in atherosclerotic plaques (AP) and their associations with AP instability in men with coronary atherosclerosis. Metabolic molecules (adipocytokines and metabolic hormones) of adipose tissue can act as enzymes, hormones or growth factors in modulating insulin resistance and lipid and glucose metabolism and indirectly influence the course of the atherosclerotic process. This study included 48 men from whom 139 coronary artery (CA) samples were collected during coronary artery bypass grafting, after obtaining the informed consent. According to the histological conclusion, 84 (60.4%) CA plaques were stable, 44 (31.7%) were unstable, and 11 histological samples had a conditionally unchanged CA intima (7.9%). The concentrations of adiponectin, adipsin, resistin, GLP-1, glucagon, and secretin were measured in AP homogenates by multiplex analysis using the Human Metabolic Hormone V3 panel (MILLIPLEX, Germany). During the study, demographic and anthropometric characteristics, medical history, and presence of chronic diseases were recorded. The glucagon concentration in the conditionally unchanged intima was 16.7% lower and in the fragments of unstable atherosclerotic plaques 41.2% lower than in fragments of stable APs. However, the glucagon concentration in stable APs was 28% higher than in unstable APs. The secretin concentration in the conditionally unchanged intima was also lower than in stable APs by 41.2%, while in stable APs, the secretin concentration was 20% higher than in unstable APs. The adiponectin concentrations were directly correlated with serum high-density lipoprotein cholesterol (HDL-C) concentrations (r=0.286; p=0.002), while the secretin concentrations were inversely correlated with serum HDL-C concentrations (r= -0.199; p=0.038). The probability of having an unstable AP (in relation to conditionally unchanged intima) increases by 35.8% with an increase in the AP glucagon concentration by 1 pg/mg protein. The probability of having a stable AP (in relation to unchanged intima) increases by 29.4% with an increase in the AP glucagon concentration by 1 pg/mg protein and by 10.1% with an increase in the AP secretin concentration by 1 pg/mg protein. The AP adiponectin concentration directly correlates and the AP secretin concentration inversely correlates with the serum concentration of HDL-C. The presence of both stable and unstable APs is directly associated with the AP glucagon concentration in men with coronary atherosclerosis. The AP secretin concentration is directly associated with plaque stability in men with coronary atherosclerosis. Further thorough study of the identified markers in atherosclerotic lesions will allow using them as potential targets for therapy.

Insulin receptors in vascular smooth muscle cells regulate plaque stability of atherosclerosis.

Increased prevalence of acute myocardial infarction related to diabetes and insulin resistance is associated with elevated risk for unstable atherosclerotic plaques, which are characterized by reduced vascular smooth muscle cells (VSMC) and extracellular matrix (ECM) and increased inflammation. Thus, insulin resistance may reduce plaque stability as deleting insulin receptors (IR) in VSMC decreased their proliferation and enhanced apoptosis. Direct effects of insulin on VSMC to alter plaque composition were studied using mice with double knockout of ApoE and IR genes in VSMC with SMIRKO/ApoE-/- and Myh11-CreERT2EYFP+/ApoE-/- and Myh11-CreERT2EYFP+IRKO/ApoE-/- mice, which were also used for lineage tracing studies. Compared to ApoE-/- mice, SMIRKO/ApoE-/-- mice exhibited more atherosclerotic plaques, which contained less VSMC and collagen, but increased levels of VSMC apoptosis and necrotic areas. Lineage tracing studies showed that Icam1+ Vcam1+ VSMC was inflammatory VSMC, which increased in aortas of Myh11-CreERT2EYFP+IRKO/ApoE-/- mice compared to control mice. Isolated VSMC lacking IR expressed higher inflammatory cytokines than cells with IR. Cell based studies indicated that insulin's anti-apoptotic and pro-proliferative effects in VSMC were mediated via activation of IR/Akt pathway, which were decreased in VSMC from SMIRKO or high fat diet (HFD) mice. Analysis of IR targets that regulated inflammatory cytokines in VSMC showed that thrombospondin 1 (Thbs1) and Mmp2 were consistently increased with loss of IR. Insulin inhibited Thbs1 expression, but not Mmp2, by p-Akt/p-FoxO1 pathways in VSMC from ApoE-/- mice, which was impaired in cells from SMIRKO/ApoE-/-- mice. Thbs1 further induced Icam1 and Mmp2 expressions in VSMC. Insulin via IR has significant actions in VSMC to decrease inflammation, apoptosis and ECM turnover via the activation of Akt and FoxO1 pathways. Inhibition of insulin actions and related pathways related to insulin resistance and diabetes may contribute to the formation of unstable atherosclerotic plaques.

A novel mechanism of ferroptosis inhibition-enhanced atherosclerotic plaque stability: YAP1 suppresses vascular smooth muscle cell ferroptosis through GLS1.

Atherosclerosis is a leading cause of cardiovascular diseases (CVDs), often resulting in major adverse cardiovascular events (MACEs), such as myocardial infarction and stroke due to the rupture or erosion of vulnerable plaques. Ferroptosis, an iron-dependent form of cell death, has been implicated in the development of atherosclerosis. Despite its involvement in CVDs, the specific role of ferroptosis in atherosclerotic plaque stability remains unclear. In this study, we confirmed the presence of ferroptosis in unstable atherosclerotic plaques and demonstrated that the ferroptosis inhibitor ferrostatin-1 (Fer-1) stabilizes atherosclerotic plaques in apolipoprotein E knockout (Apoe-/-) mice. Using bioinformatic analysis combining RNA sequencing (RNA-seq) with single-cell RNA sequencing (scRNA-seq), we identified Yes-associated protein 1 (YAP1) as a potential key regulator of ferroptosis in vascular smooth muscle cells (VSMCs) of unstable plaques. Invitro, we found that YAP1 protects against oxidized low-density lipoprotein (oxLDL)-induced ferroptosis in VSMCs. Mechanistically, YAP1 exerts its anti-ferroptosis effects by regulating the expression of glutaminase 1 (GLS1) to promote the synthesis of glutamate (Glu) and glutathione (GSH). These findings establish a novel mechanism where the inhibition of ferroptosis promotes the stabilization of atherosclerotic plaques through the YAP1/GLS1 axis, attenuating VSMC ferroptosis. Thus, targeting the YAP1/GLS1 axis to suppress VSMC ferroptosis may represent a novel strategy for preventing and treating unstable atherosclerotic plaques.

Neutrophil extracellular traps mediate the crosstalk between plaque microenvironment and unstable carotid plaque formation

The development of unstable carotid atherosclerotic plaques is associated with the induction of neutrophil extracellular traps (NETs) via the activation of diverse inflammatory mediators in the circulating bloodstream. However, the underlying mechanisms through which NETs influence the microenvironment of atherosclerotic plaques and contribute to the development of unstable carotid plaques remain largely elusive. The objective of this study was to elucidate the role of myeloid differentiation protein 1 (MD-1, LY86)-induced NETs underlying the crosstalk between unstable plaque formation and the plaque microenvironment. We employed bioinformatics analysis to identify key genes associated with carotid-unstable plaque, followed by comprehensive validation using various experimental approaches on tissue specimens and plasma samples classified based on pathological characteristics. Patients with carotid-unstable plaques exhibited elevated plasma concentrations of MD-1 (LY86), while patients with stable plaques demonstrated comparatively lower levels. Furthermore, soluble MD-1 was found to induce the formation of NETs through activation of Toll-like receptor signaling pathway. The proliferative and immature vascularization effects of NETs on endothelial cells, as well as their inhibitory impact on cell migration, are directly correlated with the concentration of NETs. Additionally, NETs were found to activate the NF-κB signaling pathway, thereby upregulating ICAM1, VCAM1, MMP14, VEGFA, and IL6 expression in both Human umbilical vein endothelial cells (HUVECs) and HAECs. Subsequently, a significant increase in intraplaque neovascularization by NETs results in poor carotid plaque stability, and NETs in turn stimulate macrophages to produce more MD-1, generating a harmful positive feedback loop. Our findings suggest that soluble MD-1 in the bloodstream triggers the production of NETs through activation of the Toll-like receptor signaling pathway and further indicate NETs mediate a crosstalk between the microenvironment of the carotid plaque and the neovascularization of the intraplaque region. Inhibiting NETs formation or MD-1 secretion may represent a promising strategy to effectively suppress the development of unstable carotid plaques.

Identification and experimental validation of KMO as a critical immune-associated mitochondrial gene in unstable atherosclerotic plaque

BackgroundThe heightened risk of cardiovascular and cerebrovascular events is associated with the increased instability of atherosclerotic plaques. However, the lack of effective diagnostic biomarkers has impeded the assessment of plaque instability currently. This study was aimed to investigate and identify hub genes associated with unstable plaques through the integration of various bioinformatics tools, providing novel insights into the detection and treatment of this condition.MethodsWeighted Gene Co-expression Network Analysis (WGCNA) combined with two machine learning methods were used to identify hub genes strongly associated with plaque instability. The cell-type identification by estimating relative subsets of RNA transcripts (CIBERSORT) method was utilized to assess immune cell infiltration patterns in atherosclerosis patients. Additionally, Gene Set Variation Analysis (GSVA) was conducted to investigate the potential biological functions, pathways, and mechanisms of hub genes associated with unstable plaques. To further validate the diagnostic efficiency and expression of the hub genes, immunohistochemistry (IHC), quantitative real-time polymerase chain reaction (RT-qPCR), and enzyme-linked immunosorbent assay (ELISA) were performed on collected human carotid plaque and blood samples. Immunofluorescence co-staining was also utilized to confirm the association between hub genes and immune cells, as well as their colocalization with mitochondria.ResultsThe CIBERSORT analysis demonstrated a significant decrease in the infiltration of CD8 T cells and an obvious increase in the infiltration of M0 macrophages in patients with atherosclerosis. Subsequently, two highly relevant modules (blue and green) strongly associated with atherosclerotic plaque instability were identified. Through intersection with mitochondria-related genes, 50 crucial genes were identified. Further analysis employing least absolute shrinkage and selection operator (LASSO) logistic regression and support vector machine recursive feature elimination (SVM-RFE) algorithms revealed six hub genes significantly associated with plaque instability. Among them, NT5DC3, ACADL, SLC25A4, ALDH1B1, and MAOB exhibited positive correlations with CD8 T cells and negative correlations with M0 macrophages, while kynurenine 3-monooxygenas (KMO) demonstrated a positive correlation with M0 macrophages and a negative correlation with CD8 T cells. IHC and RT-qPCR analyses of human carotid plaque samples, as well as ELISA analyses of blood samples, revealed significant upregulation of KMO and MAOB expression, along with decreased ALDH1B1 expression, in both stable and unstable samples compared to the control samples. However, among the three key genes mentioned above, only KMO showed a significant increase in expression in unstable plaque samples compared to stable plaque samples. Furthermore, the expression patterns of KMO in human carotid unstable plaque tissues and cultured mouse macrophage cell lines were assessed using immunofluorescence co-staining techniques. Finally, lentivirus-mediated KMO silencing was successfully transduced into the aortas of high-fat-fed ApoE-/- mice, with results indicating that KMO silencing attenuated plaque formation and promoted plaque stability in ApoE-/- mice.ConclusionsThe results suggest that KMO, a mitochondria-targeted gene associated with macrophage cells, holds promise as a valuable diagnostic biomarker for assessing the instability of atherosclerotic plaques.

PON1 rs662, rs854560 and TRIB1 rs17321515, rs2954029 Gene Polymorphisms Are Associated with Lipid Parameters in Patients with Unstable Angina.

Acute coronary heart disease (CHD) is mainly caused by the rupture of an unstable atherosclerotic plaque. Many different factors can cause stenosis or even occlusion of the coronary artery lumen, such as vasculitis and platelet aggregation. Our study was performed to assess the association between PON1 rs662, rs854560 and TRIB1 rs17321515, rs2954029 polymorphisms and the risk of CHD, as well as the association between studied polymorphisms and selected clinical parameters affecting the risk of developing ischemic heart disease. A total of 232 patients with unstable angina were enrolled in this study. There were no statistically significant differences in the PON1 rs662, rs854560 and TRIB1 rs17321515, rs2954029 polymorphism distributions between the total study and control groups. Total cholesterol plasma levels were significantly higher in patients with the PON1 rs662 TT genotype compared to those with the CC+TC genotypes, as well as in patients with the PON1 rs854560 TT genotype compared to those with the AA+AT genotypes. LDL plasma levels were significantly increased in patients with the PON1 rs854560 TT genotype compared to those with the AA+AT genotypes. Plasma levels of HDL were significantly decreased in patients with the TRIB1 rs17321515 AA+AG genotypes compared to those with the GG genotype, as well as in patients with the TRIB1 rs2954029 AA+AT genotypes compared to those with the TT genotype. Our results suggest that the analysed polymorphisms are not risk factors for unstable angina in the Polish population. However, the results of this study indicate an association between the PON1 rs662, rs854560 and TRIB1 rs17321515, rs2954029 polymorphisms with lipid parameters in patients with coronary artery disease.

Identification of Critical Genes Differentiating Stable and Unstable Atherosclerotic Plaques: A Bioinformatic and Computational Analysis.

Identification of biomarkers to distinguish between stable and unstable plaque formation would be very useful to predict plaque vulnerability. We downloaded microarray profiles of gene set enrichment (GSE) accession numbers including GSE71226 and GSE20680 (group A: containing healthy vs stable plaque samples) and GSE62646 and GSE34822 (group B: containing stable vs unstable plaque samples) from Gene expression omnibus (GEO) database. Differentially expressed genes were compared in both data sets of each group. Ten and 12 key genes were screened in groups A and B, respectively. Gene Ontology (GO) enrichment was applied by the plugin "BiNGO" (Biological networks gene ontology tool) of the Cytoscape. The key genes were mostly enriched in the biological process of positive regulation of the cellular process. The protein-protein interaction and co-expression network were analyzed by the STRING (search tool for the retrieval of interacting genes/proteins) and GeneMANIA (gene multiple association network integration algorithm) plugin of Cytoscape, respectively, which showed that Epidermal growth factor (EGF), Heparin-binding EGF like growth factor (HBEGF), and Matrix metalloproteinase 9 (MMP9) were at the core of the network. Further validation of key genes using two datasets showed that Phosphodiesterase 5A (PDE5A) and Protein S (PROS1) were decreased in unstable plaques, while Suppressor of cytokine signaling (SOCS3), HBEGF, and Leukocyte immunoglobulin-like receptor B4 (LILRB4) were increased. The present study used several datasets to identify key genes associated with stable and unstable atherosclerotic plaque.

Differences in Stable and Unstable Atherosclerotic Plaque.

Differences in Stable and Unstable Atherosclerotic Plaque.

OxLDL as a prognostic biomarker of plaque instability in patients qualified for carotid endarterectomy.

Atherosclerotic plaque instability increases the risk of stroke. As such, determining the nature of an instability atherosclerotic plaque may speed up qualification for carotid endarterectomy (CEA), thus reducing the risk of acute vascular events. The aim of the study was to determine the diagnostic value of oxidized LDL cholesterol (ox-LDL), matrix metalloproteinase 9 (MMP-9) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in serum as a prognostic markers of instability atherosclerotic plaques. Serum was collected from 67 patients who underwent CEA in accordance with the qualification criteria. The levels of ox-LDL, MMP-9 and 8-OHdG were assessed by ELISA. The predictive value of the markers was determined based on an ROC curve, and the cut-off points with the highest sensitivity and specificity were determined. Patients with unstable atherosclerotic plaque had significantly higher serum ox-LDL, MMP-9 and 8-OHdG values. It was found that in patients before CEA, ox-LDL >31.4 ng/mL was associated with an 82.5% probability of unstable atherosclerotic plaque, MMP-9 >113.1 ng/mL with 78.6%, and 8-OHdG >2.15 ng/mL with 64.7%. Multivariate regression analysis found ox-LDL to be an independent factor associated with plaque instability. Patients with unstable plaques tend to have higher serum levels of ox-LDL, MMP-9 and 8-OHdG compared to those with stable plaques. The optimal cut-off point for ox-LDL (AUC 0.86, p <0.0001) was 31.14 ng/mL, with 91.18% sensitivity and 78.79% specificity. The high sensitivity and specificity of ox-LDL suggests that it can be used as an independent marker of plaque instability.

Novel Mouse Model of Myocardial Infarction, Plaque Rupture, and Stroke Shows Improved Survival With Myeloperoxidase Inhibition.

Thromboembolic events, including myocardial infarction (MI) or stroke, caused by the rupture or erosion of unstable atherosclerotic plaques are the leading cause of death worldwide. Although most mouse models of atherosclerosis develop lesions in the aorta and carotid arteries, they do not develop advanced coronary artery lesions. Moreover, they do not undergo spontaneous plaque rupture with MI and stroke or do so at such a low frequency that they are not viable experimental models to study late-stage thrombotic events or to identify novel therapeutic approaches for treating atherosclerotic disease. This has stymied the development of more effective therapeutic approaches for reducing these events beyond what has been achieved with aggressive lipid lowering. Here, we describe a diet-inducible mouse model that develops widespread advanced atherosclerosis in coronary, brachiocephalic, and carotid arteries with plaque rupture, MI, and stroke. We characterized a novel mouse model with a C-terminal mutation in the scavenger receptor class B, type 1 (SR-BI), combined with Ldlr knockout (designated SR-BI∆CT/∆CT/Ldlr-/-). Mice were fed Western diet (WD) for 26 weeks and analyzed for MI and stroke. Coronary, brachiocephalic, and carotid arteries were analyzed for atherosclerotic lesions and indices of plaque stability. To validate the utility of this model, SR-BI∆CT/∆CT/Ldlr-/- mice were treated with the drug candidate AZM198, which inhibits myeloperoxidase, an enzyme produced by activated neutrophils that predicts rupture of human atherosclerotic lesions. SR-BI∆CT/∆CT/Ldlr-/- mice show high (>80%) mortality rates after 26 weeks of WD feeding because of major adverse cardiovascular events, including spontaneous plaque rupture with MI and stroke. Moreover, WD-fed SR-BI∆CT/∆CT/Ldlr-/- mice displayed elevated circulating high-sensitivity cardiac troponin I and increased neutrophil extracellular trap formation within lesions compared with control mice. Treatment of WD-fed SR-BI∆CT/∆CT/Ldlr-/- mice with AZM198 showed remarkable benefits, including >90% improvement in survival and >60% decrease in the incidence of plaque rupture, MI, and stroke, in conjunction with decreased circulating high-sensitivity cardiac troponin I and reduced neutrophil extracellular trap formation within lesions. WD-fed SR-BI∆CT/∆CT/Ldlr-/- mice more closely replicate late-stage clinical events of advanced human atherosclerotic disease than previous models and can be used to identify and test potential new therapeutic agents to prevent major adverse cardiac events.

The Blood Plasma Lipidomic Profile in Atherosclerosis of the Brachiocephalic Arteries.

According to the World Health Organization, ischemic stroke is the second leading cause of death in the world. Frequently, it is caused by brachiocephalic artery (BCA) atherosclerosis. Timely detection of atherosclerosis and its unstable course can allow for a timely response to potentially dangerous changes and reduce the risk of vascular complications. Omics technologies allow us to identify new biomarkers that we can use in diagnosing diseases. This research included 90 blood plasma samples. The study group comprised 52 patients with severe atherosclerotic lesions BCA, and the control group comprised 38 patients with no BCA atherosclerosis. Targeted and panoramic lipidomic profiling of their blood plasma was carried out. There was a statistically significant difference (p < 0.05) in the values of the indices saturated fatty acids (FAs), unsaturated FAs, monounsaturated FAs, omega-3, and omega-6. Based on the results on the blood plasma lipidome, we formed models that have a fairly good ability to determine atherosclerotic lesions of the brachiocephalic arteries, as well as a model for identifying unstable atherosclerotic plaques. According only to the panoramic lipidome data, divided into groups according to stable and unstable atherosclerotic plaques, a significant difference was taken into account: p value < 0.05 and abs (fold change) > 2. Unfortunately, we did not observe significant differences according to the established plasma panoramic lipidome criteria between patients with stable and unstable plaques. Omics technologies allow us to obtain data about any changes in the body. According to our data, statistically significant differences in lipidomic profiling were obtained when comparing groups with or without BCA atherosclerosis.

MiR-92b-3p modulates apoptosis in smooth muscle cells through BCL2L11 regulation, unravelling novel therapeutic strategies for unstable plaques

Abstract Funding Acknowledgements None. Smooth muscle cell (SMC) apoptosis is a contributory factor to plaque rupture in atherosclerosis, thereby promoting plaque destabilization through various mechanisms such as thrombogenic activation and plaque microcalcification. Immunohistochemical analysis has revealed elevated expression of proteins associated with intrinsic apoptosis, such as BCL2L11 (Bim), in unstable atherosclerotic plaques. Our hypothesis posits that Bim is a direct target of miR-92b-3p, an understudied microRNA, prompting an investigation into its role in regulating apoptosis in SMCs. Our objective is to discern a novel therapeutic axis for preventing plaque rupture by employing miRNA-based targeted interventions. Within a model of primary human vascular cells, we employed various in vitro techniques, including PCR, Western Blot, Live cell imaging, and ELISA. Lipotransfection facilitated transient modulation of miR-92b-3p, using both knockdown and elevation, while an siRNA transfection model was also utilized. MiR-92b-3p exhibits robust expression in late atherosclerotic lesions in vivo (p&amp;lt;0.001) and demonstrates heightened levels in smooth muscle cells (SMCs) compared to endothelial cells (ECs) in vitro (p&amp;lt;0.01) and in vivo in respective tissues (p&amp;lt;0.01). Bim, a direct target of miR-92b-3p, experiences upregulation post-miR-92b-3p knockdown and downregulation following pre-miR-92b-3p introduction into SMCs, both at mRNA and protein levels (p&amp;lt;0.01, p&amp;lt;0.01). Apoptosis increases in growth-medium cultured SMCs after miR-92b-3p knockdown (p&amp;lt;0.05), but not in senescent SMCs, ECs, or basal-medium treated SMCs. Live-cell imaging reveals a reduction in SMC count after anti-miR-92b-3p transfection (p&amp;lt;0.01), accompanied by cell shrinkage indicative of apoptosis 72 hours post-transfection (p&amp;lt;0.05). Growth factor stimulation results in miR-92b-3p upregulation (p&amp;gt;0.05) and Bim downregulation in SMCs. SiRNA knockdown of BIM in SMCs abolishes apoptosis induction through miR-92b-3p knockdown (p&amp;lt;0.05). Conversely, in apoptotic SMCs, miR-92b-3p upregulation protects cells from apoptosis (p&amp;lt;0.05). MiR-92b-3p effectively modulates mitochondrial apoptosis in SMCs by targeting BIM. This regulatory impact is exclusive to proliferative SMCs, known for their deleterious involvement in atherosclerotic plaques. Cumulatively, the elevation of miR-92b-3p via targeted miRNA therapeutics or miRNA-drug interactions in the advanced stages of atherosclerosis presents a potential therapeutic avenue for averting plaque rupture.

Mild phototherapy mediated by IR780-Gd-OPN nanomicelles suppresses atherosclerotic plaque progression through the activation of the HSP27-regulated NF-κB pathway

Reducing plaque lipid content and enhancing plaque stability without causing extensive apoptosis of foam cells are ideal requirements for developing a safe and effective treatment of atherosclerosis. In this study, we synthesized IR780-Gd-OPN nanomicelles by conjugating osteopontin (OPN) and loading a gadolinium-macrocyclic ligand (Gd-DOTA) onto near-infrared dye IR780-polyethylene glycol polymer. The nanomicelles were employed for mild phototherapy of atherosclerotic plaques and dual-mode imaging with near-infrared fluorescence and magnetic resonance. In vitro results reveal that the mild phototherapy mediated by IR780-Gd-OPN nanomicelles not only activates heat shock protein (HSP) 27 to protect foam cells against apoptosis but also inhibits the nuclear factor kappa-B (NF-κB) pathway to regulate lipid metabolism and macrophage polarization, thereby diminishing the inflammatory response. In vivo results further validate that mild phototherapy effectively reduces plaque lipid content and size while simultaneously enhancing plaque stability by regulating the ratio of M1 and M2-type macrophages. In summary, this study presents a promising approach for developing a safe and highly efficient method for the precise therapeutic visualization of atherosclerosis. Statement of significanceThe rupture of unstable atherosclerotic plaques is a major cause of high mortality rates in cardiovascular diseases. Therefore, the ideal outcome of atherosclerosis treatment is to reduce plaque size while enhancing plaque stability. To address this challenge, we designed IR780-Gd-OPN nanomicelles for mild phototherapy of atherosclerosis. This treatment can effectively reduce plaque size while significantly improving plaque stability by increasing collagen fiber content and elevating the ratio of M2/M1 macrophages, which is mainly attributed to the inhibition of the NF-κB signaling pathway by mild phototherapy-activated HSP27. In summary, our proposed mild phototherapy strategy provides a promising approach for safe and effective treatment of atherosclerosis.

Abstract 1033: Loss Of Serine Hydroxymethyltransferase 2 In Macrophages Blunts Glutathione And Enhances Ceramide Synthesis To Accelerate Atherosclerosis

Increasing evidence suggests an important role for amino acid metabolism in atherosclerotic cardiovascular disease (ASCVD), highlighting potential biomarkers, causative factors, and therapeutic targets. Among all amino acids, lower circulating glycine is consistently reported to be associated with enhanced ASCVD severity. The amino acid serine is the main precursor for glycine, and a lower glycine:serine ratio is associated with more advanced and unstable atherosclerotic plaques. The mitochondrial serine hydroxymethyltransferase 2 (SHMT2) catalyzes the bulk of glycine formation from serine, and is critical in development since global knockout mice are nonviable. We found that SHMT2 is highly expressed in macrophages in both human and mouse atherosclerotic plaques. LPS-treated macrophages displayed reduced SHMT2 expression concomitant with a lower intracellular glycine:serine ratio. To study the role of SHMT2 in macrophages, we developed novel myeloid-specific Shmt2 knockout mice ( Shmt2 MKO ). Metabolomics and stable isotope tracing studies revealed that macrophages lacking SHMT2 have a lower glycine:serine ratio leading to attenuated de novo synthesis of glutathione and enhanced formation of the ceramide precursor, sphinganine. Accordingly, the loss of SHMT2 in macrophages enhanced superoxide production and ceramide accumulation. To determine the role of macrophage SHMT2 in atherosclerosis, we crossed the Shmt2 MKO mice with apolipoprotein E-deficient ( Apoe -/- ) mice. After 12 weeks on Western diet, Shmt2 MKO / Apoe -/- mice showed no differences in plasma lipid or amino acid profiles as compared to Shmt2 flox / Apoe -/- mice. Nevertheless, plaque area and necrotic core size were significantly enhanced in Shmt2 MKO / Apoe -/- mice. Taken together, macrophage SHMT2 plays a critical role in atherosclerosis by regulating redox and ceramide metabolism.

A novel rabbit model of atherosclerotic vulnerable plaque established by cryofluid-induced endothelial injury

Acute thrombosis secondary to atherosclerotic plaque rupture is the main cause of acute cardiac and cerebral ischemia. An animal model of unstable atherosclerotic plaques is highly important for investigating the mechanism of plaque rupture and thrombosis. However, current animal models involve complex operations, are costly, and have plaque morphologies that are different from those of humans. We aimed to establish a simple animal model of vulnerable plaques similar to those of humans. Rabbits were randomly divided into three groups. Group A was given a normal formula diet for 13 weeks. Group C underwent surgery on the intima of the right carotid artery with – 80 °C cryofluid-induced injury after 1 week of a high-fat diet and further feeding a 12-week high-fat diet. Group B underwent the same procedure as Group C but without the – 80 °C cryofluid. Serum lipid levels were detected via ELISA. The plaque morphology, stability and degree of stenosis were evaluated through hematoxylin–eosin (HE) staining, Masson trichrome staining, Elastica van Gieson staining (EVG), and oil red O staining. Macrophages and inflammatory factors in the plaques were assessed via immunohistochemical analysis. The serum low-density lipoprotein cholesterol (LDL-C), triglyceride (TG), and total cholesterol (TC) levels in groups B and C were significantly greater than those in group A. No plaque formation was observed in group A. The plaques in group B were very small. In group C, obvious plaques were observed in the blood vessels, and the plaques exhibited a thin fibrous cap, a large lipid core, and partially visible neovascularization, which is consistent with the characteristics of vulnerable plaques. In the plaques of group C, a large number of macrophages were present, and matrix metalloproteinase 9 (MMP-9) and lectin-like oxidized LDL receptor 1 (LOX-1) were abundantly expressed. We successfully established a rabbit model of vulnerable carotid plaque similar to that of humans through the combination of cryofluid-induced endothelial injury and a high-fat diet, which is feasible and cost effective.

Integrating machine learning algorithms and single-cell analysis to identify gut microbiota-related macrophage biomarkers in atherosclerotic plaques.

The relationship between macrophages and the gut microbiota in patients with atherosclerosis remains poorly defined, and effective biological markers are lacking. This study aims to elucidate the interplay between gut microbial communities and macrophages, and to identify biomarkers associated with the destabilization of atherosclerotic plaques. The goal is to enhance our understanding of the underlying molecular pathways and to pave new avenues for diagnostic approaches and therapeutic strategies in the disease. This study employed Weighted Gene Co-expression Network Analysis (WGCNA) and differential expression analysis on atherosclerosis datasets to identify macrophage-associated genes and quantify the correlation between these genes and gut microbiota gene sets. The Random Forest algorithm was utilized to pinpoint PLEK, IRF8, BTK, CCR1, and CD68 as gut microbiota-related macrophage genes, and a nomogram was constructed. Based on the top five genes, a Non-negative Matrix Factorization (NMF) algorithm was applied to construct gut microbiota-related macrophage clusters and analyze their potential biological alterations. Subsequent single-cell analyses were conducted to observe the expression patterns of the top five genes and the interactions between immune cells. Finally, the expression profiles of key molecules were validated using clinical samples from atherosclerosis patients. Utilizing the Random Forest algorithm, we ultimately identified PLEK, IRF8, CD68, CCR1, and BTK as gut microbiota-associated macrophage genes that are upregulated in atherosclerotic plaques. A nomogram based on the expression of these five genes was constructed for use as an auxiliary tool in clinical diagnosis. Single-cell analysis confirmed the specific expression of gut microbiota-associated macrophage genes in macrophages. Clinical samples substantiated the high expression of PLEK in unstable atherosclerotic plaques. Gut microbiota-associated macrophage genes (PLEK, IRF8, CD68, CCR1, and BTK) may be implicated in the pathogenesis of atherosclerotic plaques and could serve as diagnostic markers to aid patients with atherosclerosis.

Relationship between fibroblast growth factor in plasma and carotid plaque neovascularization: a pilot study.

Unstable atherosclerotic carotid plaques with intraplaque neovascularization (IPN) carry a substantial risk for ischemic stroke. Conventional ultrasound methods fall short in detecting IPN, where superb microvascular imaging (SMI) has emerged as a promising tool for both visualizing and quantification. High levels of fibroblast growth factor 23 (FGF-23) have, in observational studies, been suggested as related to cardiovascular morbidity and mortality. The association of FGF-23 to atherosclerotic carotid plaque instability remains relatively unexplored. A cohort of twenty-nine patients with ≥50% atherosclerotic carotid stenosis underwent conventional carotid ultrasound, SMI, and blood tests, including measurement of FGF-23 in plasma. Nineteen patients were characterized as symptomatic and ten as asymptomatic. Our major findings were: i) Higher FGF-23 levels were strongly correlated with increased SMI-assessed IPN. ii) Neo-vessel count recorded by quantitative SMI was positively correlated to increased FGF-23 levels, but not with basic FGF levels. (iii) In contrast, traditional risk factors for plaque instability exhibited no noteworthy associations with SMI-assessed IPN or with FGF-23 levels. This pilot study suggest the potential of FGF-23 as a valuable marker for neovascularization and atherosclerotic carotid plaque instability as a risk factor for ischemic stroke. Further research involving larger cohorts and prospective data is necessary to understand FGF-23's role in this context comprehensively.

Characterization of the proteome of stable and unstable carotid atherosclerotic plaques using data-independent acquisition mass spectrometry

BackgroundCurrently, noninvasive imaging techniques and circulating biomarkers are still insufficient to accurately assess carotid plaque stability, and an in-depth understanding of the molecular mechanisms that contribute to plaque instability is still lacking.MethodsWe established a clinical study cohort containing 182 patients with carotid artery stenosis. After screening, 39 stable and 49 unstable plaques were included in the discovery group, and quantitative proteomics analysis based on data independent acquisition was performed for these plaque samples. Additionally, 35 plaques were included in the validation group to validate the proteomics results by immunohistochemistry analysis.ResultsA total of 397 differentially expressed proteins were identified in stable and unstable plaques. These proteins are primarily involved in ferroptosis and lipid metabolism-related functions and pathways. Plaque validation results showed that ferroptosis- and lipid metabolism-related proteins had different expression trends in stable plaques versus unstable fibrous cap regions and lipid core regions. Ferroptosis- and lipid metabolism-related mechanisms in plaque stability were discussed.ConclusionsOur results may provide a valuable strategy for revealing the mechanisms affecting plaque stability and will facilitate the discovery of specific biomarkers to broaden the therapeutic scope.