A definition of advanced types of atherosclerotic lesions and a histological classification of atherosclerosis. A report from the Committee on Vascular Lesions of the Council on Arteriosclerosis, American Heart Association

Ezh2 Shapes T Cell Plasticity to Drive Atherosclerosis

BACKGROUND

The activation and polarization of T cells play a crucial role in atherosclerosis and dictate athero-inflammation. The epigenetic enzyme EZH2 (enhancer of zeste homolog 2) mediates the H3K27me3 (trimethylation of histone H3 lysine 27) and is pivotal in controlling T cell responses.

METHODS

To detail the role of T cell EZH2 in atherosclerosis, we used human carotid endarterectomy specimens to reveal plaque expression and geography of EZH2. Atherosclerosis-prone Apoe (apolipoprotein E)-deficient mice with CD (cluster of differentiation) 4+ or CD8+ T cell-specific Ezh2 deletion (Ezh2cd4-knockout [KO], Ezh2cd8-KO) were analyzed to unravel the role of T cell Ezh2 in atherosclerosis and T cell-associated immune status.

RESULTS

EZH2 expression is elevated in advanced human atherosclerotic plaques and primarily expressed in the T cell nucleus, suggesting the importance of canonical EZH2 function in atherosclerosis. Ezh2cd4-KO, but not Ezh2cd8-KO, mice showed reduced atherosclerosis with fewer advanced plaques, which contained less collagen and macrophages, indicating that Ezh2 in CD4+ T cells drives atherosclerosis. In-depth analysis of CD4+ T cells of Ezh2cd4-KO mice revealed that absence of Ezh2 results in a type 2 immune response with increased Il-4 (interleukin 4) gene and protein expression in the aorta and lymphoid organs. In vitro, Ezh2-deficient T cells polarized macrophages toward an anti-inflammatory phenotype. Single-cell RNA-sequencing of splenic T cells revealed that Ezh2 deficiency reduced naive, Ccl5+ (C-C motif chemokine ligand 5) and regulatory T cell populations and increased the frequencies of memory T cells and invariant natural killer T (iNKT) cells. Flow cytometric analysis identified a shift toward Th2 (type 2 T helper) effector CD4+ T cells in Ezh2cd4-KO mice and confirmed a profound increase in splenic iNKT cells with increased expression of Plzf (promyelocytic leukemia zinc finger), which is the characteristic marker of the iNKT2 subset. Likewise, Zbtb16 ([zinc finger and BTB domain containing 16], the Plzf-encoding gene) transcripts were elevated in the aorta of Ezh2cd4-KO mice, suggesting an accumulation of iNKT2 cells in the plaque. H3K27me3-chromatin immunoprecipitation followed by quantitative polymerase chain reaction showed that T cell-Ezh2 regulates the transcription of the Il-4 and Zbtb16 genes.

CONCLUSIONS

Our study uncovers the importance of T cell EZH2 in human and mouse atherosclerosis. Inhibition of Ezh2 in CD4+ T cells drives type 2 immune responses, resulting in an accumulation of iNKT2 and Th2 cells, memory T cells and anti-inflammatory macrophages that limit the progression of atherosclerosis.

Impaired CAMK4 Activity Limits Atherosclerosis and Reprograms Myelopoiesis

BACKGROUND

Chronic inflammation is a major driver of atherosclerotic cardiovascular disease, and therapeutics that target inflammation reduce cardiac events beyond levels seen with strategies targeting cholesterol alone. RNA sequencing revealed increased expression of CaMK4 (calcium/calmodulin-dependent protein kinase IV) in advanced/unstable human carotid artery plaque. We validated this finding in mouse and human atherosclerotic lesions, demonstrating increased CaMK4 in plaque macrophages. Therefore, we hypothesized that CaMK4 would promote inflammation and impair resolution in atherosclerosis.

METHODS

We obtained mice in which exon 3 within the kinase domain of CaMK4 is deleted, leading to degradation and deletion of the gene (Camk4-/-). Control and Camk4-/- mice were injected with a gain-of-function AAV (adeno-associated virus) 8-PCSK9 (proprotein convertase subtilisin/kexin type 9) virus, rendering them hypercholesterolemic, and fed a high-fat/high-cholesterol diet for 12 weeks.

RESULTS

Hypercholesterolemic Camk4-/- mice developed smaller and more stable lesions compared with control mice. Surprisingly, Camk4-/- mice had a peripheral monocytosis with skewing of monocyte populations toward the nonclassical Ly6clow subset, suggesting a less inflammatory monocyte population. Silencing or inhibition of CaMK4 in human monocytes recapitulated this phenotype. In response to hypercholesterolemia, which promotes myelopoiesis, Camk4-/- mice had markedly more myeloid progenitors. Camk4-/- monocytes expressed higher levels of genes associated with myeloid differentiation and recruitment of ATF6 (activating transcription factor 6) to conserved binding sites. In addition, Camk4-/- monocytes expressed higher levels of Nr4a1, which promotes conversion of Ly6chigh to Ly6clow monocytes. Camk4-/- monocytes failed to efficiently traffic in vitro and in vivo. Bone marrow-derived macrophages generated from Camk4-/- marrow had a more proreparative phenotype than control macrophages, consistent with our in vivo observations in the plaque.

CONCLUSIONS

These findings suggest that CaMK4 is an important regulator of the myelopoietic response to hypercholesterolemia through ATF6-mediated transcriptional regulation and that loss of functional CaMK4 promotes a proreparative phenotype in myeloid cells. Therefore, targeting CaMK4 may offer a unique way to target the progression of atherosclerosis.

Accelerated atherosclerosis associated with immune checkpoint inhibitors: a systematic review and meta-analysis of pre-clinical studies

BACKGROUND

Patients with cancer treated with immune checkpoint inhibitors are at increased risk of myocardial infarction and ischemic stroke. The mechanism is incompletely understood but may involve accelerated atherosclerosis due to enhanced inflammation. Pre-clinical studies may provide insight in these mechanisms.

AIM

To assess the effects of modulating co-inhibitory immune checkpoint proteins on atherosclerosis progression in animal models.

METHODS

A systematic review was performed in MEDLINE, Embase, Web of Science, and Scopus up to March 2025. Animal studies were included if the effect of modulation of programmed cell death protein 1 (PD-1), programmed death-ligand 1 (PD-L1), cytotoxic T-lymphocyte associated protein 4 (CTLA-4), and/or lymphocyte-activation gene 3 (LAG-3) on atherosclerotic plaque size was evaluated. Secondary outcomes were plaque composition and systemic inflammation. The ratios of means (RoM) across the studies were pooled in a random effects meta-analysis. Risk of bias was assessed using the SYRCLE tool, focusing on randomization, blinding, and completeness of outcome reporting.

RESULTS

Fourteen eligible studies were included. All studies used an atherosclerotic mouse model (ApoE-/-, Ldlr-/-, ApoE3∗Leiden, or AAV8-PCSK9) and either evaluated pharmacological or genetic modulation of co-inhibitory immune checkpoint proteins. Upon inhibition, atherosclerotic plaque size in the aorta was 53 % higher in exposed mice compared to control mice (RoM, 1.53; 95 % CI, 1.29-1.83; I2 = 89 %). Plaque composition was predominantly characterized by a greater abundance of CD4+ T cells, CD8+ T cells, and macrophages. Studies stimulating co-inhibitory immune checkpoint proteins corroborated these findings and demonstrated that atherosclerotic plaque size was reduced by 28 % in treated mice compared to controls (RoM, 0.72; 95 % CI, 0.65-0.80; I2 = 85 %). This reduction was paralleled by a decrease in the number of macrophages and T cells in plaques.

CONCLUSION

Immune checkpoint inhibition leads to increased plaque inflammation and a significant increase in murine atherosclerotic plaque size. These changes may reflect the cause of the increased risk of myocardial infarction and ischemic stroke in patients treated with immune checkpoint inhibitors.

Insights from autopsy-initiated pathological studies of the pathogenesis and clinical manifestations of atherosclerosis and ischemic heart disease: Part II. Ischemic heart disease

CONTEXT

Ischemic heart disease (IHD) due to coronary atherosclerosis constitutes the leading cause of morbidity and mortality worldwide. This review was undertaken to retrospectively analyze the lines of research that generated the evidence for our contemporary understanding of atherosclerosis-based coronary artery disease and to provide a rationale for continued support for autopsy-based research in order to make further progress in reduction of the morbidity and mortaility from IHD.

OBJECTIVES

To analyze the contributions of the autopsy to complement and validate other lines of investigation in determining the complex interactions between coronary artery alterations linked to the major manifestations of coronary atherosclerosis, namely, coronary thrombosis, acute myocardial infarction, and sudden cardiac death.

DATA SOURCES

Systematic search on PubMed to gather relevant studies concerning autopsy studies and reviews of the pathology and pathogenesis of atherosclerosis, ischemic heart disease, coronary atherosclerosis, coronary thrombosis, myocardial infarction and sudden cardiac death.

CONCLUSIONS

An extensive search of the published literature has confirmed the continuing importance of the autopsy as a powerful tool to understand the pathogenesis, clinical features, and therapeutic options for the treatment of atherosclerosis and its major manifestation, ischemic heart disease. This has been described in the Part I companion of the present review. Autopsy-initiated studies have documented the prevalence and clinicopathological significance of atherosclerosis in different human populations and its relationship to risk factors. It has been shown that the clinically silent phase of ischemic heart disease (IHD) begins in the first decades of life. Pathological studies have clarified the complex relationship between coronary atherosclerosis, coronary thrombosis, and myocardial ischemic events. These studies also have elucidated the pathological basis of sudden cardiac death. Insights from these studies also have been important in developing and evaluating strategies for continued progress in reducing the morbidity and mortality attributed to atherosclerosis and IHD.

LncRNA uc003pxg.1 Interacts With miR-339-5p Promote Vascular Endothelial Cell Proliferation, Migration and Angiogenesis

BACKGROUND AND OBJECTIVES

This study aimed to investigate the roles of lncRNA uc003pxg.1 and miR-339-5p in regulating the occurrence and development of coronary heart disease.

METHODS

First, the expression levels of uc003pxg.1 and miR-339-5p were verified in peripheral blood mononuclear cells of clinical samples. Then, the target gene was identified using high-throughput sequencing combined with bioinformatics. Human umbilical vein endothelial cells (HUVECs) were transfected with si-uc003pxg.1, miR-339-5p mimic and miR-339-5p inhibitor, and the expression of related genes was detected by reverse transcription-quantitative polymerase chain reaction and western blotting. EdU, CCK-8, Cell scratch and Transwell assays were used to analyze the effects of uc003pxg.1 and miR-339-5p on cell proliferation and migration.

RESULTS

The expression of uc003pxg.1 and miR-339-5p was negatively correlated in clinical samples and HUVECs. The si-uc003pxg.1 and miR-339-5p mimic decreased the proliferation and migration of HUVECs and decreased the expression of transforming growth factor (TGF)-β1 and α-smooth muscle actin (SMA). The protein expression levels of TGF-β1, α-SMA, CD31, collagen I, collagen III and endoglin were decreased, and angiogenesis was weakened. The miR-339-5p inhibitor had the opposite effect.

CONCLUSIONS

Our study revealed that upregulation of uc003pxg.1 and downregulation of miR-339-5p in vitro promote cell proliferation, cell migration and angiogenesis and upregulate the expression of TGF-β1, α-SMA, CD31, collagen I, collagen III and endoglin, which may lead to the development of vascular atherosclerosis.

Reprogramming human macrophages in symptomatic carotid stenosis: Stabilization of atherosclerotic carotid plaques

BACKGROUND AND AIMS

Inflammation is a precursor to atherosclerotic plaque destabilisation, leading to ischaemic events like stroke. Since macrophage phenotypes can be influenced by their microenvironment, we aimed to stabilise plaques and reduce the risk of recurrent ischaemic events using clinically relevant anti-inflammatory agents.

METHODS

Thirteen carotid plaques from stroke/Transient Ischaemic Attack (TIA) patients undergoing carotid endarterectomy were analysed using immunofluorescence stain to identify macrophage markers (CD68, CD86, MRC1). An in vitro model of human blood-derived macrophages was used to evaluate the effects of statins and glucocorticoids on macrophage-specific markers using RT-qPCR, Western Blot, and immunofluorescence staining. The physiological effects of dexamethasone on macrophages and human carotid plaques were further studied ex vivo.

RESULTS

The macrophage population (CD68+) in the carotid plaques was dominated by "double-positive" (CD86+MRC1+) macrophages (67.8 %), followed by "M1-like" (CD86+MRC1-) (16.5 %), "M2-like" (CD86-MRC1+) (8.7 %) and "double-negative" (CD86-MRC1-) (7.0 %) macrophages. M1-like macrophages were more prevalent in unstable plaque sections than stable ones (p = 0.0022). Exposure to dexamethasone increased macrophage MRC1 gene expression in vitro and ex vivo. It also reduced the expression of the Oxidised Low-Density Lipoprotein Receptor 1 (OLR1) gene and protein, leading to reduced oxLDL uptake in foam cell assays.

CONCLUSIONS

Clinically relevant concentrations of glucocorticoids may shift human macrophages to a less inflammatory state, thus reducing their ability for oxidised LDL uptake. In contrast, this anti-inflammatory mechanism was not observed in response to statins. These findings suggest that glucocorticoids could help prevent ischemic events in patients with advanced atherosclerosis.

Molecular landscape of atherosclerotic plaque progression: insights from proteomics, single-cell transcriptomics and genomics

BACKGROUNDS

Atherosclerosis is a major contributor to cardiovascular diseases worldwide. Despite advancements in understanding its pathology, significant gaps remain in the molecular characterization of atherosclerotic plaques. This study addresses this gap by extensively profiling the proteomic landscape of carotid atherosclerotic plaques, classified under the American Heart Association (AHA) types IV to VI, to identify potential biomarkers and therapeutic targets.

METHODS

The study employed an integrated approach using data-independent acquisition (DIA) proteomics, single-cell RNA sequencing, and Mendelian randomization (MR). A total of 87 human carotid plaques were analyzed to identify and quantify protein expression. These proteins were then mapped to specific regions within the plaques, such as the fibrous cap and lipid core, and further validated in independent samples and single-cell datasets. Furthermore, Mendelian randomization techniques were employed to assess causal relationships between identified proteins levels and ischemic stroke.

RESULTS

The proteomic analysis of the 87 carotid plaques revealed 6143 proteins, highlighting diverse expression profiles across different plaque stages. Notably, proteins like CD44 and GAL-1 were predominantly expressed in the fibrous cap, suggesting a role in plaque stability, while TREM2, SMAD3, and IL-6R showed higher expression in the lipid core, indicating involvement in inflammatory processes. These findings were further corroborated by single-cell RNA sequencing, revealing cell-specific expression patterns that align with the observed proteomic data. Additionally, MR analysis indicated the causal role of IL6R, CD44, and SMAD3 in ischemic stroke.

CONCLUSIONS

This study provides valuable insights into the progression of atherosclerotic plaques, identifying key proteins that could serve as potential biomarkers and therapeutic targets. It enhances our molecular understanding of atherosclerosis and opens up new avenues for treatment. Additionally, our study demonstrates the accuracy and robustness of proteomics in prioritizing genes associated with plaque-related traits.

Insights from autopsy-initiated pathological studies of the pathogenesis and clinical manifestations of atherosclerosis and ischemic heart disease: Part I. Atherosclerosis

CONTEXT

Ischemic heart disease (IHD) due to coronary atherosclerosis constitutes the leading cause of morbidity and mortality worldwide. This review was undertaken to document the historical basis for our contemporary understanding of atherosclerosis-based disease and to provide a rationale for continued support for autopsy-based research to make further progress in reducing the morbidity and mortality from atherosclerosis-related disease.

OBJECTIVES

To analyze the contributions of the autopsy-initiated pathological studies to complement and validate other lines of investigation in determining the pathology and pathogenesis of the leading worldwide cause of morbidity and mortality, namely, atherosclerosis and its major complications of coronary atherosclerosis, ischemic heart disease, coronary thrombosis, acute myocardial infarction, and sudden cardiac death.

DATA SOURCES

Systematic search on PubMed to gather relevant studies concerning autopsy studies and reviews of the pathology and pathogenesis of atherosclerosis, ischemic heart disease, coronary atherosclerosis, coronary thrombosis, myocardial infarction, and sudden cardiac death CONCLUSIONS: Extensive published reports have confirmed the continuing importance of the autopsy as a powerful tool to understand the pathogenesis, clinical features, and therapeutic options for major diseases. This specifically has been shown by the analysis of atherosclerosis and its major manifestation of ischemic heart disease, as presented in this (Part I) and its companion (Part II) review. Autopsy-initiated pathological studies have documented the prevalence and natural history of atherosclerosis in different human populations in relationship to the prevalence of risk factors and established that the clinically silent phase of the disease begins in the first decades of life. Insights from these studies have been essential in developing and evaluating strategies for continued progress in preventing and controlling the disability and death associated with atherosclerotic heart disease.

Fibronectin-dependent integrin signaling drives EphA2 expression in vascular smooth muscle cells

Vascular smooth muscle cells undergo a phenotypic shift to a "synthetic" phenotype during atherosclerosis characterized by downregulation of contractile markers and augmented proliferation, migration, and extracellular matrix deposition. While absent in contractile smooth muscle cells, the receptor tyrosine kinase EphA2 shows enhanced expression in synthetic vascular smooth muscle in vitro and in atherosclerotic plaques in vivo. EphA2 deletion in atheroprone ApoE knockout mice reduces plaque size, fibrous tissue, and smooth muscle content. However, the mechanisms regulating smooth muscle EphA2 expression remain unknown. Although serum strongly induces EphA2 expression, individual growth factors and insulin all failed to stimulate EphA2 expression in smooth muscle cells. In contrast, adhesion to fibronectin stimulated the expression of EphA2, while blunting serum-induced fibronectin deposition attenuated EphA2 expression, suggesting a critical role for fibronectin signaling. Fibronectin binds to a subset of extracellular matrix-binding integrins, and blocking fibronectin-integrin interactions or inhibiting specific fibronectin-binding integrins both attenuated EphA2 expression. Furthermore, pharmacological inhibition of fibronectin-binding integrins significantly reduced EphA2 expression in atherosclerotic plaques. RNA sequencing analysis of fibronectin-associated gene expression pointed to NF-κB as a likely transcription factor mediating fibronectin-responsive genes. Adhesion to fibronectin enhanced NF-κB activation in smooth muscle cells and inhibiting NF-κB blunted EphA2 expression associated with fibronectin. In addition, chromatin immunoprecipitation showed that NF-κB directly interacts with the EphA2 promoter, and mutating this site blunts fibronectin-dependent EphA2 promoter activity. Together these data identify a novel role for fibronectin-dependent integrin signaling in the induction of smooth muscle EphA2 expression.NEW & NOTEWORTHY Here, we demonstrate a novel interplay between cell-cell and cell-matrix adhesions, showing that fibronectin-dependent integrin signaling promotes NF-κB activation and interaction with the EphA2 promoter to drive smooth muscle EphA2 expression, whereas integrin inhibition attenuates EphA2 expression in atherosclerotic plaques in vivo. Although this relationship has clear implications on smooth muscle fibroproliferative remodeling in atherosclerosis, the matrix-specific regulation of EphA2 expression may impact a variety of pathological conditions.

Single cell RNA sequencing of haematopoietic cells in fresh and frozen human atheroma tissue

AIMS

Single-cell RNA sequencing (scRNA-seq) is a powerful method for exploring the cellular heterogeneity within human atheroma but typically requires fresh tissue to preserve cell membrane integrity, limiting the feasibility of large-scale biobanking for later analysis. The aim of this study was to determine whether cryopreservation of fragile and necrotic atheroma tissue affects the viability and transcriptomic profiles of haematopoietic cells in subsequent scRNA-seq analysis, enabling the use of cryopreserved atheroma samples for future research.

METHODS AND RESULTS

We performed scRNA-seq on five paired fresh and cryopreserved atheroma samples-three from coronary arteries and two from carotid arteries. Each sample was enzymatically digested, sorted for CD45+ haematopoietic cells, and processed using the 10× Genomics scRNA-seq workflow. Half of each sample was processed immediately, while the other half was cryopreserved in liquid nitrogen for an average of 5 weeks before thawing and processing. In carotid artery samples, we noted the absence of LYVE1+ macrophages, likely due to the loss of the adventitial layer during endarterectomy procedures. Our results indicated that cryopreservation modestly affected cellular integrity, leading to an increase in the relative abundance of mitochondrial RNA in frozen samples. Minimal differences were observed between fresh and cryopreserved samples in uniquely detected transcripts, cell clustering, or transcriptional profiles within haematopoietic populations.

CONCLUSIONS

Our study demonstrates that cryopreserved human atheroma samples can be successfully profiled using scRNA-seq, with comparable transcriptomic data to that obtained from fresh samples. These findings suggest that cryopreservation is a viable method for biobanking atheroma tissues, facilitating large-scale studies without the need for immediate sample processing.

Oxidized LDL stimulates PKM2-mediated mtROS production and phagocytosis

Oxidized low-density lipoprotein (oxLDL) promotes proatherogenic phenotypes in macrophages, accelerating the progression of atherosclerosis. Our previous studies demonstrated that oxLDL binds to its receptor CD36, stimulating mitochondrial reactive oxygen species (mtROS), which are critical in atherosclerosis development. However, the mechanisms underlying mtROS induction and their effects on macrophage cellular functions remain poorly understood. Macrophages rely on phagocytosis to clear pathogens, apoptotic cells, or other particles, a process critical for tissue homeostasis. Dysregulated or excessive particle ingestion, a key step in phagocytosis, can lead to lipid overloading and foam cell formation, a hallmark of atherosclerosis. In this study, we showed that macrophages pretreated with oxLDL exhibit increased particle ingestion, a phagocytic response significantly attenuated in Cd36-null macrophages. Further investigations revealed that oxLDL-induced phagocytosis depends on mtROS, as their suppression inhibited the process. In vivo, atherosclerosis-prone Apoe-null mice on a high-fat diet exhibited increased mtROS levels and enhanced phagocytic activity in aortic foamy macrophages compared to those from chow diet-fed mice, supporting a role of mtROS in promoting lesional macrophage phagocytosis. Mechanistically, we identified a novel signaling pathway whereby oxLDL/CD36 interaction induces the translocation of the cytosolic enzyme pyruvate kinase muscle 2 (PKM2) to mitochondria. Disruption of PKM2 mitochondrial translocation using siRNA knockdown or a specific chemical inhibitor reduced mtROS production and attenuated oxLDL-induced phagocytosis. In conclusion, our findings reveal a novel oxLDL-CD36-PKM2 signaling axis that drives mtROS production and phagocytosis in atherogenic macrophages.

LncRNA MIR181A1HG Deficiency Attenuates Vascular Inflammation and Atherosclerosis

BACKGROUND

Endothelial cell (EC) dysfunction and vascular inflammation are critical in the initiation and progression of atherosclerosis. Long noncoding RNAs play a critical role in vascular pathology, but relatively little is known about their involvement in controlling vascular inflammation. MIR181A1HG is a conserved long noncoding RNA located in juxtaposition with miR-181a1 and miR-181b1, both involved in vascular inflammation. The study aims to investigate the role of MIR181A1HG in regulating vascular inflammation.

METHODS

We examined the expression of MIR181A1HG in both human and mouse atherosclerotic lesions. Loss-of-function and gain-of-function studies, and multiple RNA-protein interaction assays were used to investigate the role and molecular mechanisms of MIR181A1HG in vascular inflammation and atherosclerosis. The atherosclerotic phenotypes of MIR181A1HG-/-ApoE-/- mice were analyzed in combination with single-cell RNA sequencing. The transcriptional regulation of MIR181A1HG was verified through luciferase reporter and chromatin immunoprecipitation assays.

RESULTS

MIR181A1HG expression was abundant in ECs and significantly increased in both human and mouse atherosclerotic lesions. MIR181A1HG-/-ApoE-/- mice had reduced NLRP (NLR family pyrin domain containing) 3 inflammasome signaling, EC activation, monocyte infiltration, and atherosclerotic lesion formation. Genetic deletion of MIR181A1HG in myeloid sells did not alter the progression of atherosclerosis. Single-cell RNA sequencing analysis revealed that MIR181A1HG deficiency reduced the proportion of immune cells and enriched anti-inflammation pathways in EC clusters in atherosclerotic lesions. In contrast, EC-specific MIR181A1HG overexpression promoted NLRP3 inflammasome signaling, EC activation, and atherosclerotic lesion formation, effects that were reversed by pharmacological inhibition of NLRP3 (MCC950). MIR181A1HG was transcriptionally activated via an NF-κB (nuclear factor kappa B)/p65-dependent pathway. Mechanistically, MIR181A1HG mediated these effects on regulating NLRP3 inflammasome and EC activation in part through decoying Foxp1 (forkhead box transcription factor 1) away from the promoters of target genes, which was independent of the miR-181a1/b1 cluster. Finally, EC-specific Foxp1 silencing reversed the antiatherosclerotic effect mediated by MIR181A1HG-deletion in vivo.

CONCLUSIONS

These findings identify MIR181A1HG as a central driver of vascular inflammation in atherosclerosis by its ability to decoy Foxp1 away from target gene promoters and activate NLRP3 inflammasome in the vascular endothelium. Our study suggests MIR181A1HG as a future therapeutic target for vascular inflammatory disease states.

Coronary Calcification: Types, Morphology and Distribution

The development and progression of coronary calcification is of growing interest with the emergence of new imaging modalities and calcium modifying technologies that can facilitate optimal results during complex percutaneous coronary intervention (PCI). Coronary atherosclerotic disease typically begins within the intima with pathological intimal thickening and microcalcifications (>0.5 μm and <15 μm). These microcalcifications can coalesce into larger areas of calcification, including sheet calcium, which is typically seen in fibrocalcific plaque, nodular calcification and calcified nodules. Calcified nodules typically protrude into the vessel lumen. Erosive calcified nodules lack the coverage of protective anti-aggregatory endothelium and frequently show adherence of intraluminal thrombus. Greater calcification within coronary plaque does not correlate with an increased risk of acute coronary syndrome, however, coronary calcium can lead to challenges with stent delivery and full stent expansion during PCI. An understanding of plaque morphology, distribution of calcium, degree of calcification and underlying shape will enable interventional cardiologists to appropriately interpret intravascular ultrasound and optical coherence tomography imaging findings and optimise results during complex PCI.

ALKBH5 Regulates Macrophage Senescence and Accelerates Atherosclerosis by Promoting CCL5 m6A Modification

BACKGROUND

Senescent foamy macrophages are key drivers of atherosclerosis and plaque instability. N6-methyladenosine (m6A) modification of RNA plays an important role in the development of various diseases including aging. Here, we aim to investigate the role of m6A modification of RNA in the formation of senescent foamy macrophages in atherosclerosis.

METHODS

To assess m6A methylation, macrophages were isolated from the atherosclerotic plaques of patients with atherosclerosis, and Apoe-/- mice were fed a high-fat diet using CD68+ magnetic beads. An ALKBH5 (alkB homolog 5)f/f, Lyz2 (lysozyme 2)Cre, Apoe-/- mouse model was generated to determine the infiltration of senescent foamy macrophages into plaques and atherosclerosis progression. Methylated RNA immunoprecipitation, RNA immunoprecipitation sequencing, and dual-luciferase assays were performed to explore the mechanisms underlying the ALKBH5-mediated formation of senescent foamy macrophages.

RESULTS

Decreased m6A methylation and increased ALKBH5 expression were observed in arterial plaques and infiltrating macrophages from patients and mice with atherosclerosis. Compared with control mice, ALKBH5f/f, Lyz2Cre, Apoe-/- mice exhibited fewer atherosclerosis plaques with greater stability, which was attributed to the suppression of senescent foamy macrophage formation and senescence-associated secretory phenotype. In addition, ALKBH5 deletion reduced the mRNA expression level of CCL5 (CC chemokine ligand 5) by increasing m6A methylation in macrophages, which disrupts the stability of CCL5 mRNA. Mechanistically, ALKBH5 promoted senescent foamy macrophage formation through the CCL5/CCR5 (CC chemokine receptor 5)/autophagy signaling pathway. CCL5 also recruited CD8+ IFN (interferon)γ+ T cells via the CCL5-CCR5 axis. The ALKBH5 inhibitor IOX1 and the CCR5 antagonist maraviroc were identified as potential clinical interventions for inhibiting senescent foamy macrophage formation and atherosclerosis progression.

CONCLUSIONS

Myeloid ALKBH5 deletion attenuates atherosclerosis progression by suppressing the formation of senescent foamy macrophages and the recruitment of CD8+IFNγ+ T cells. These findings identify ALKBH5, CCL5, and CCR5 as novel therapeutic targets for atherosclerosis.

Redefining Macrophage Heterogeneity in Atherosclerosis: A Focus on Possible Therapeutic Implications

Atherosclerosis is a lipid disorder where modified lipids (especially oxidized LDL) induce macrophage foam cell formation in the aorta. Its pathogenesis involves a continuum of persistent inflammation accompanied by dysregulated anti-inflammatory responses. Changes in the immune cell status due to differences in the lesional microenvironment are crucial in terms of plaque development, its progression, and plaque rupture. Ly6Chi monocytes generated through both medullary and extramedullary cascades act as one of the major sources of plaque macrophages and thereby foam cells. Both monocytes and monocyte-derived macrophages also participate in pathological events in atherosclerosis-associated multiple organ systems through inter-organ communications. For years, macrophage phenotypes M1 and M2 have been shown to perpetuate inflammatory and resolution responses; nevertheless, such a dualistic classification is too simplistic and contains severe drawbacks. As the lesion microenvironment is enriched with multiple mediators that possess the ability to activate macrophages to diverse phenotypes, it is obvious that such cells should demonstrate substantial heterogeneity. Considerable research in this regard has indicated the presence of additional macrophage phenotypes that are exclusive to atherosclerotic plaques, namely Mox, M4, Mhem, and M(Hb) type. Furthermore, although the concept of macrophage clusters has come to the fore in recent years with the evolution of high-dimensional techniques, classifications based on such 'OMICS' approaches require extensive functional validation as well as metabolic phenotyping. Bearing this in mind, the current review provides an overview of the status of different macrophage populations and their role during atherosclerosis and also outlines possible therapeutic implications.

Serum chemokines combined with multi-modal imaging to evaluate atherosclerotic plaque stability in patients undergoing carotid endarterectomy

Background

Although imaging tools are crucial in identifying features of atherosclerotic plaque, there remains a lack of consensus on the use of serological markers for assessing high-risk plaques.

Methods

Patients diagnosed with CAS who met the criteria for CEA were categorized as the operation group, while those without CAS were designated as the control group. Multi-modal imaging was conducted pre- and post-CEA to evaluate plaque features, such as the volume of calcification and LRNC, intra-plaque hemorrhage, and the degree of carotid stenosis. Serum chemokine levels were measured in both groups before CEA and on the 7th day post-surgery. Morphological features of carotid artery specimens were assessed using H&E and IHC (CD68 and α-SMA) staining to evaluate plaque stability.

Results

No significant differences in the degree of CAS between the operation and control groups. Among the operation group, 26 out of 52 patients were identified as vulnerable plaques. The volume of LRNC was significantly higher in vulnerable plaque, whereas the volume of calcification was significantly lower in vulnerable plaque compared to stable plaque confirmed by multi-modal imaging. Vulnerable plaque exhibited a thin fibrous cap covered an LRNC, intra-plaque hemorrhage, and macrophage infiltration. Stable plaque were characterized by small lipid cores covered by a thick fibrous cap, with minimal macrophage infiltration. Chemokine levels were significantly elevated in CAS patients compared to controls, and decreased significantly on the 7th day post-CEA. In patients with vulnerable plaque, lower levels of CX3CL1, CXCL12, CCL19, and CCL21, but higher levels of CCL2 and CCL5, were observed compared to patients with stable plaque. Correlation analysis further indicated that CX3CL1 and CXCL12 levels were positively associated with calcification volume. While CCL2 and CCL5 levels were positively associated, and CCL19 and CCL21 negatively associated, with LRNC volume. Multivariate analysis suggested that CXCL12 was an independent protective factor and LRNC volume as an independent risk factor for plaque vulnerability. The combination with multi-modal imaging and serological markers enhanced both the sensitivity (87.31%) and specificity (92.31%) in predicting plaque stability, with an AUC of 0.9001.

Conclusion

Combining multi-modal imaging with serological markers provides a more comprehensive evaluation of atherosclerotic plaque features.

Apolipoprotein A1 deficiency increases macrophage apoptosis and necrotic core development in atherosclerotic plaques in a Bim-dependent manner

In advanced atherosclerotic lesions, macrophage apoptosis contributes to plaque progression and the formation of necrotic cores, rendering plaques vulnerable to rupture. The proapoptotic protein B-cell lymphoma 2 [Bcl-2] interacting mediator of cell death (Bim) plays a crucial role in mediating apoptosis in macrophages under prolonged endoplasmic reticulum stress. HDL has been shown to suppress macrophage apoptosis induced by endoplasmic reticulum stressors. To investigate the impact of apolipoprotein A1 (ApoA1) deficiency, associated with reduced HDL levels, on necrotic core growth and plaque apoptosis, we introduced ApoA1 deficiency into low-density lipoprotein receptor (LDLR) knockout mice and fed them a high-fat diet for 10 weeks. ApoA1-deficient Ldlr KO mice developed advanced plaques characterized by large necrotic cores, increased apoptosis, and elevated Bim expression in macrophages within the plaques. To assess whether deletion of Bim could mitigate this development, mice underwent bone marrow transplantation with bone marrow from either Bim-deficient mice or from mice with a deletion of myeloid-derived Bim driven by LyzM-cre. Inhibiting Bim in all bone marrow-derived cells led to leukocytosis, reductions in plasma cholesterol and triglyceride levels, and decreased plaque apoptosis, necrotic core, and plaque sizes in ApoA1 and Ldlr double-KO mice but not in Ldlr KO mice. Likewise, conditional deletion of Bim in the myeloid compartment of ApoA1 and Ldlr double-KO mice also reduced apoptosis, necrotic core sizes, and plaque sizes, without inducing leukocytosis or lowering plasma cholesterol levels. These findings suggest that ApoA1 deficiency triggers apoptosis in myeloid cells through a Bim-dependent pathway, significantly contributing to the development of necrotic cores and the progression of atherosclerotic plaques.

Serum proteomic profiling reveals potential predictive indicators for coronary artery calcification in stable ischemic heart disease

Coronary artery calcification (CAC) is a common complication in patients with stable ischemic heart disease (SIHD). However, the early diagnosis and understanding of the pathogenesis of CAC in SIHD patients remain underdeveloped. This study aimed to analyze aberrant alterations in the serum proteome of SIHD patients, as well as SIHD patients with severe CAC (CAC_SIHD), and to explore the potential risk factors of CAC in SIHD patients. Serum proteomic profiles were obtained from individuals with SIHD (n = 6), CAC_SIHD (n = 6), and healthy controls (n = 9), and were analyzed using nano liquid chromatography tandem mass spectrometry (LC-MS/MS). The aberrant alterations in proteins and immune cells in the serum of SIHD and CAC_SIHD patients were characterized through differential protein expression analysis and single-sample gene set enrichment analysis analysis, respectively. Differentially expressed proteins (DEPs) were further subjected to gene ontology functional enrichment and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses. Finally, Receiver Operating Characteristic analysis was performed on the DEPs between SIHD and CAC_SIHD to identify potential predictive factors of CAC. Abnormalities in multiple complement pathways and lipid metabolism were observed in SIHD and CAC_SIHD patients. Moreover, SIHD and CAC_SIHD were characterized by an increased presence of T cells and natural killer cells, along with a reduced presence of B cells. Subsequent analysis of serum proteins revealed that RNASE1 and MSLN may be potential predictive indicators for the early detection and diagnosis of CAC in SIHD patients. In conclusion, our research extensively examined the variations in serum proteins in patients with SIHD and CAC_SIHD, identifying key indicators and metabolic pathways associated with these conditions. These findings not only provide new insights into the pathological mechanisms of SIHD and CAC_SIHD, but also suggest potential factors for the early diagnosis of CAC in SIHD patients, which imply potential clinical applications.

Histology-Grounded Automated Plaque Subtype Segmentation in Intravascular Optical Coherence Tomography

Background

Intravascular optical coherence tomography (IVOCT) adoption has been limited by the complexity of image interpretation. The interpretation of histologic subtypes beyond lipid, calcium, and fibrous is challenging to human readers. To assist and standardize IVOCT image analysis, we demonstrate an artificial intelligence algorithm based on a histology data set that identifies lipid pools, fibrofatty, calcified lipid, and calcified fibrous in human coronary arteries for the first time.

Methods

Sixty-seven human coronary arteries were imaged with IVOCT within 24 hours after death and then underwent histologic examination. IVOCT images were coregistered and segmented into histologic subtypes: lipid pools, fibrofatty tissue, calcified lipid, and calcified fibrous tissue. Experiments regarding lipidic plaque included fibrofatty tissue, lipid pools, and calcified lipids. Experiments regarding calcium plaque included calcified fibrous and calcified lipid plaques. Optical coherence tomography images were lumen justified and cropped to a depth of 200 pixels (1 mm) to account for limited optical coherence tomography penetration depth. IVOCT segmentations from expert readers guided by histology were used to train segmentation neural networks.

Results

For each data set, in addition to testing each of these subtypes individually, we trained and tested the model on the combined grouping of subtypes. Combined lipid subtypes achieved validation and test Dice (Sørensen-Dice coefficient) of 0.63 and 0.40, respectively, whereas combined calcium subtypes achieved validation and test Dice of 0.66 and 0.62, respectively.

Conclusions

This histology-validated artificial intelligence algorithm driven by histologic subtypes can identify plaque subtypes not evident to a human reader. The reported algorithm can provide a fast solution to IVOCT image interpretation.

Discussion on the comparison of Raman spectroscopy and cardiovascular disease-related imaging techniques and the future applications of Raman technology: a systematic review

Cardiovascular disease (CVD) is a major cause of unnatural death worldwide, so timely diagnosis of CVD is crucial for improving patient outcomes. Although the traditional diagnostic tools can locate plaque and observe inner wall of blood vessel structure, they commonly have radioactivity and cannot detect the chemical composition of the plaque accurately. Recently emerging Raman techniques can detect the plaque composition precisely, and have the advantages of being fast, high-resolution and marker-free. This makes Raman have great potential for detecting blood samples, understanding disease conditions, and real-time monitoring. This review summarizes the origin and state-of-art of Raman techniques, including the following aspects: (a) the principle and technical classification of Raman techniques; (b) the applicability of Raman techniques and its comparison with traditional diagnostic tools at different diagnosis targets; (c) the applicability of Raman spectroscopy in advanced CVD. Lastly, we highlight the possible future applications of Raman techniques in CVD diagnosis.

Analysis and validation of biomarkers and immune cell infiltration profiles in unstable coronary atherosclerotic plaques using bioinformatics and machine learning

Introduction

Decreased stability of coronary atherosclerotic plaques correlates with a heightened risk of acute coronary syndrome (ACS). Thus, early diagnosis and treatment of unstable plaques are imperative in averting adverse cardiovascular events. This study aims to identify diagnostic biomarkers for unstable coronary atherosclerotic plaques and investigate the role of immune cell infiltration in their formation.

Methods

The datasets GSE163154 and GSE111782, obtained from the gene expression omnibus (GEO) database, were amalgamated for bioinformatics analysis, using the dataset GSE43292 as a test set. Sequentially, we performed principal component analysis (PCA), differential gene expression analysis, enrichment analysis, weighted gene co-expression network analysis (WGCNA), utilized a machine learning algorithm to screen key genes, conducted receiver operating characteristic (ROC) curve analysis and nomogram model to assess biomarker diagnostic efficacy, validated the biomarkers, and analyzed immune cell infiltration.

Results

In conclusion, enrichment analyses demonstrate that genes are significantly enriched in inflammatory and immune-related pathways. We identified HSPA2 and GEM as key genes and validated them experimentally. Significant differences existed in immune cell infiltration between subgroups. Additionally, HSPA2 and GEM showed significant associations with a wide range of immune cells.

Discussion

HSPA2 and GEM can function as diagnostic biomarkers for unstable coronary atherosclerotic plaques. In combination with immune cell infiltration analyses, our study provides new insights into the future study of unstable plaque occurrence and molecular mechanisms.

Carotid Stenosis and Stroke: Historical Perspectives Leading to Current Challenges

The carotid artery is unique; it is the only vessel to bifurcate into a bulb larger than itself. The history of its anatomic description, understanding of its pathophysiology and evolution of its imaging are relevant to current controversies regarding measurement of stenosis, surgical/endovascular therapies and medical management of carotid stenosis in stroke prevention. Treatment decisions on millions of symptomatic and asymptomatic patients are routinely based on information from clinical trials from over 30 years ago. This article briefly summarizes the highlights of past research in key areas and discuss how they led to current challenges of diagnosis and treatment.

Macrophages overexpressing interleukin-10 target and prevent atherosclerosis: Regression of plaque formation and reduction in necrotic core

Atherosclerosis, a slowly progressing inflammatory disease, is characterized by the presence of monocyte-derived macrophages. Interventions targeting the inflammatory characteristics of atherosclerosis hold promising potential. Although interleukin (IL)-10 is widely acknowledged for its anti-inflammatory effects, systemic administration of IL-10 has limitations due to its short half-life and significant systemic side effects. In this study, we aimed to investigate the effectiveness of an approach designed to overexpress IL-10 in macrophages and subsequently introduce these genetically modified cells into ApoE-/- mice to promote atherosclerosis regression. We engineered RAW264.7 cells to overexpress IL-10 (referred to as IL-10M) using lentivirus vectors. The IL-10M exhibited robust IL-10 secretion, maintained phagocytic function, improved mitochondrial membrane potentials, reduced superoxide production and showed a tendency toward the M2 phenotype when exposed to inflammatory stimuli. IL-10M can selectively target plaques in ApoE-/- mice and has the potential to reduce plaque area and necrotic core at both early and late stages of plaque progression. Moreover, there was a significant reduction in MMP9, a biomarker associated with plaque rupture, in IL-10M-treated plaques from both the early and late intervention groups. Additionally, the administration of IL-10M showed no obvious side effects. This study serves as proof that cell therapy based on anti-inflammatory macrophages might be a promising strategy for the intervention of atherosclerosis.

Identification of Protein Networks and Biological Pathways Driving the Progression of Atherosclerosis in Human Carotid Arteries Through Mass Spectrometry-Based Proteomics

Vulnerable atherosclerotic plaques, especially hemorrhaged lesions, are the major cause of mortalities related to vascular pathologies. The early identification of vulnerable plaques helps to stratify patients at risk of developing acute vascular events. In this study, proteomics analyses of human carotid artery samples collected from patients with atheromatous plaques and complicated lesions, respectively, as well as from healthy controls were performed. The proteins isolated from the carotid artery samples were analyzed by a bottom-up shotgun approach that relied on nanoflow liquid chromatography-tandem mass spectrometry analyses (LC-MS/MS) using both data-dependent (DDA) and data-independent (DIA) acquisitions. The data obtained by high-resolution DIA analyses displayed a stronger distinction among groups compared to DDA analyses. Differentially expressed proteins were further examined using Ingenuity Pathway Analysis® with focus on pathological and molecular processes driving atherosclerosis. From the more than 150 significantly regulated canonical pathways, atherosclerosis signaling and neutrophil extracellular trap signaling were verified by protein-targeted data extraction. The results of our study are expected to facilitate a better understanding of the disease progression's molecular drivers and provide inspiration for further multiomics and hypothesis-driven studies.

Cardiovascular positron emission tomography imaging of fibroblast activation: A review of the current literature

Fibrosis is one of the key healing responses to injury, especially within the heart, where it helps to maintain structural integrity following acute insults such as myocardial infarction. However, if it becomes dysregulated, then fibrosis can become maladaptive, leading to adverse remodelling, impaired cardiac function and heart failure. Fibroblast activation protein is exclusively expressed by activated fibroblasts, the key effector cells of fibrogenesis, and has a unique extracellular domain that is an ideal ligand for novel molecular imaging probes. Fibroblast activation protein inhibitor (FAPI) radiotracers have been developed for positron emission tomography (PET) imaging, demonstrating high selectivity for activated fibroblasts across a range of different pathologies and disparate organ systems. In this review, we will summarise the role of fibroblast activation protein in cardiovascular disease and how FAPI radiotracers might improve the assessment and treatment of patients with cardiovascular diseases.

Hemin-induced platelet activation is regulated by the ACKR3 chemokine surface receptor and has implications for passivation of vulnerable atherosclerotic plaques

In vulnerable atherosclerotic plaques, intraplaque hemorrhages (IPH) result in hemolysis of red blood cells and release of hemoglobin and free hemin. Hemin activates platelets and leads to thrombosis. Agonism of the inhibitory platelet receptor ACKR3 inhibits hemin-dependent platelet activation and thrombus formation. To characterize the effect of hemin and ACKR3 agonism on isolated human platelets, multi-color flow cytometry and classical experimental setup such as light transmission aggregometry and a flow chamber assay were used. Hemin induces platelet aggregation and ex vivo platelet-dependent thrombus formation on immobilized collagen under a low shear rate of 500 s-1, indicating that free hemin is a strong activator of platelet-dependent thrombosis. Recently, we described that ACKR3 is a prominent inhibitory receptor of platelet activation. Specific ACKR3 agonists but not conventional antiplatelet compounds such as COX-1 inhibitor (indometacin), ADP-receptor blocker (cangrelor), or PAR1 inhibitor (ML161) inhibit both hemin-dependent aggregation and thrombus formation. To further characterize the effect of hemin on platelet subpopulations, we established a multi-color flow cytometry assay. We found that hemin induces procoagulant (CD42bpos/PAC-1neg/AnnexinVpos), aggregatory (CD42bpos/PAC-1pos/AnnexinVneg), and inflammatory (CD42bpos/CXCR4pos/ACKR3pos/AnnexinVpos) platelet subpopulations. Treatment with ACKR3 agonists significantly decreased the formation of procoagulant and ACKR3pos platelets in response to hemin. We conclude that hemin is a strong activator for the formation of procoagulant platelets and thrombus formation which is dependent on the function of ACKR3. Activation of ACKR3 using specific agonists may offer a therapeutic strategy to regulate the vulnerability of atherosclerotic plaques in areas of IPH.

Immune checkpoint landscape of human atherosclerosis and influence of cardiometabolic factors

Immune checkpoint inhibitor (ICI) therapies can increase the risk of cardiovascular events in survivors of cancer by worsening atherosclerosis. Here we map the expression of immune checkpoints (ICs) within human carotid and coronary atherosclerotic plaques, revealing a network of immune cell interactions that ICI treatments can unintentionally target in arteries. We identify a population of mature, regulatory CCR7+FSCN1+ dendritic cells, similar to those described in tumors, as a hub of IC-mediated signaling within plaques. Additionally, we show that type 2 diabetes and lipid-lowering therapies alter immune cell interactions through PD-1, CTLA4, LAG3 and other IC targets in clinical development, impacting plaque inflammation. This comprehensive map of the IC interactome in healthy and cardiometabolic disease states provides a framework for understanding the potential adverse and beneficial impacts of approved and investigational ICIs on atherosclerosis, setting the stage for designing ICI strategies that minimize cardiovascular disease risk in cancer survivors.

Identification and validation of three diagnostic autophagy-related genes associated with advanced plaques and immune cell infiltration in carotid atherosclerosis based on integrated bioinformatics analyses

Background

Autophagy plays a key role in the development of carotid atherosclerosis (CAS). This study aimed to identify key autophagy-related genes (ATGs) related with CAS using bioinformatics analysis, in vivo AS mouse model, and in vitro experiments.

Methods

The GSE100927 and GSE28829 datasets were downloaded from the Gene Expression Omnibus (GEO) database. An integrated bioinformatics analyses of differentially expressed ATGs (DE-ATGs) was conducted. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed to identify the biological processes and pathways associated with DE-ATGs. Protein-protein interaction (PPI) network was constructed with the DE-ATGs to identify the key CAS-related DE-ATGs. Receiver operating characteristic (ROC) curve analysis was used to determine the diagnostic value of the key CAS-related DE-ATGs. CIBERSORT analysis was performed to determine the infiltration status of 22 immune cell types and their correlation with the expression levels of the key CAS-related DE-ATGs. Hematoxylin and eosin (HE) staining was used to estimate the plaque histology in the AS mouse model. Western blotting, quantitative real-time PCR (qRT-PCR), and immunohistochemistry (IHC) were performed to validate the protein and mRNA expression levels of the key CAS-related DE-ATGs in the in vitro and in vivo models.

Results

We compared transcriptome profiles of 12 early CAS plaques and 29 advanced CAS plaques in the GSE100927 dataset and identified 41 DE-ATGs (33 up-regulated and eight down-regulated). Functional enrichment analysis showed that the DE-ATGs were closely related with apoptosis, autophagy, and immune activation. ROC curve analysis showed that the area under the curve (AUC) values for the three key CAS-related DE-ATGs (CCL2, LAMP2, and CTSB) were 0.707, 0.977, and 0.951, respectively. CIBERSORT analyses showed close association between the three key CAS-related DE-ATGs and the infiltration of immune cell types in the plaques. Finally, the western blot, qRT-PCR, and IHC staining confirmed that CCL2, LAMP2, and CTSB were highly expressed in the plaques of the AS model mice or ox-LDL-treated human umbilical vein endothelial cells (HUVECs) and human aorta vascular smooth muscle cells (HAoSMCs).

Conclusion

We identified and validated three key CAS-associated ATGs, namely, CCL2, LAMP2, and CTSB with high diagnostic value. These three key CAS-associated ATGs are promising diagnostic markers and therapeutic targets for patients with CAS.

Erosion of the Atheroma: Wicked T Cells at the Culprit Site

PURPOSE OF REVIEW

There is a growing recognition of plaque erosion as a cause of acute coronary syndrome. This review aims to examine the potential involvement of T cells in this process.

RECENT FINDINGS

Immune-vascular interactions have been identified in the development of plaque erosions. Up to one-third of eroded plaques show evidence of active immune infiltration, with the presence of T cells. We propose that microerosions may frequently occur in association with the infiltration of T cells and macrophages in early atherosclerotic lesions. Healing of erosions could trigger the deposition of excessive extracellular matrix. The pro-inflammatory and cytotoxic actions of T cells, along with reduced endothelial integrity and other mechanisms, may subsequently give rise to clinical symptoms. To gain a better understanding of the role of T cells in plaque erosion, it is crucial to develop improved models for conducting controlled experiments and to study atherosclerosis in younger individuals.

Decoding marker genes and immune landscape of unstable carotid plaques from cellular senescence

Recently, cellular senescence-induced unstable carotid plaques have gained increasing attention. In this study, we utilized bioinformatics and machine learning methods to investigate the correlation between cellular senescence and the pathological mechanisms of unstable carotid plaques. Our aim was to elucidate the causes of unstable carotid plaque progression and identify new therapeutic strategies. First, differential expression analysis was performed on the test set GSE43292 to identify differentially expressed genes (DEGs) between the unstable plaque group and the control group. These DEGs were intersected with cellular senescence-associated genes to obtain 40 cellular senescence-associated DEGs. Subsequently, key genes were then identified through weighted gene co-expression network analysis, random forest, Recursive Feature Elimination for Support Vector Machines algorithm and cytoHubba plugin. The intersection yielded 3 CSA-signature genes, which were validated in the external validation set GSE163154. Additionally, we assessed the relationship between these CSA-signature genes and the immune landscape of the unstable plaque group. This study suggests that cellular senescence may play an important role in the progression mechanism of unstable plaques and is closely related to the influence of the immune microenvironment. Our research lays the foundation for studying the progression mechanism of unstable carotid plaques and provides some reference for targeted therapy.

Diagnostic Methods of Atherosclerotic Plaque and the Assessment of Its Prognostic Significance-A Narrative Review

Cardiovascular diseases (CVD) are a leading cause of death. The most notable cause of CVD is an atherosclerotic plaque. The aim of this review is to provide an overview of different diagnostic methods for atherosclerotic plaque relevant to the assessment of cardiovascular risk. The methods can be divided into invasive and non-invasive. This review focuses on non-invasive with attention paid to ultrasonography, contrast-enhanced ultrasonography, intravascular ultrasonography, and assessment of intima-media complex, coronary computed tomography angiography, and magnetic resonance. In the review, we discuss a number of Artificial Intelligence technologies that support plaque imaging.

Analysis of risk factors for carotid artery plaque in asymptomatic adults

OBJECTIVE

This study aimed to investigate the risk factors affecting the presence of carotid plaque in asymptomatic adults.

METHODS

Asymptomatic adults (age > 40 years, no symptoms of cardiovascular and cerebrovascular diseases) undergoing routine health examinations from physical examination department were included in this study. Carotid plaque was measured by Resona 7OB and Resona 8EXP color Doppler ultrasound and L9-3U and L4-5WU probes. The focal carotid intima-media thickness was greater than 1.1 mm, and the local protrusion of the artery wall into the artery lumen suggested the presence of carotid atherosclerotic plaque. According to their ultrasound results, 1077 asymptomatic adults were divided into a group with carotid plaque (477) and a group without carotid plaque (600).

RESULTS

A total of 1077 asymptomatic adults were included in this study, of whom 44.3% had carotid plaque. The proportion of men with carotid plaque was 84.5%. Multifactorial logistic analysis suggested that age, fasting blood glucose (FBG), total cholesterol (TC), homocysteine (Hcy) and male gender were risk factors for carotid atherosclerosis. The predictive probability of these risk factor indicators derived from the multifactorial model was calculated using receiver operating characteristic (ROC) curves with SPSS 25.0 software. The calculated area under the receiver operating characteristic curve (AUC) was 0.715 (95% CI, 0.685-0.746).

CONCLUSION

Age, FBG, TC, Hcy and male gender are risk factors for carotid atherosclerosis in asymptomatic adults. Gender differences in carotid atherosclerosis deserve further attention.

Reversal of Atherosclerotic Plaque Growth and Vulnerability: Effects of Lipid-Modifying and Anti-Inflammatory Therapeutic Agents

Atherosclerotic plaque development constitutes the primary substrate of coronary artery disease (CAD) and is the outcome of an intricate process involving endothelial damage, inflammation, and lipid retention. The clinical efficacy of many lipid-lowering therapies in patients with CAD has been well established. Over the past few decades, a substantial and significant advance regarding the use of invasive and non-invasive imaging modalities has been observed. Numerous studies have been conducted using these imaging techniques and have investigated the changes in morphology (e.g., atheroma volume) and composition (e.g., lipid burden, fibrous cap thickness, macrophage accumulation) at the plaque level that explain the improved clinical outcomes by various pharmacological interventions. Lipid-lowering agents, such as statins and proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, demonstrate direct effects on plaque volume and composition that enhance plaque stabilization and/or regression beyond the reduction of low-density lipoproteins. An increasing amount of clinical research is also focused on the role of inflammation in plaque vulnerability and future adverse cardiac events. Consequently, there is a pressing need to explore therapeutic strategies that are capable of disrupting the inflammatory response as well as reducing atheroma burden and modifying high-risk plaque characteristics. This review provides a comprehensive analysis of the current evidence regarding the effects of traditional and novel therapeutic strategies targeting modification of the lipid profile and inflammatory processes on reversing plaque growth and attenuating vulnerable features, thereby promoting plaque stabilization and passivation.

Urinary Metal Levels and Coronary Artery Calcification: Longitudinal Evidence in the Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Exposure to metals, a newly recognized risk factor for cardiovascular disease (CVD), could be related to atherosclerosis progression.

OBJECTIVES

The authors hypothesized that higher urinary levels of nonessential (cadmium, tungsten, uranium) and essential (cobalt, copper, zinc) metals previously associated with CVD would be associated with baseline and rate of change of coronary artery calcium (CAC) progression, a subclinical marker of CVD in MESA (Multi-Ethnic Study of Atherosclerosis).

METHODS

We analyzed data from 6,418 MESA participants with spot urinary metal levels at baseline (2000-2002) and 1 to 4 repeated, continuous measures of CAC over a 10-year period. We used linear mixed-effect models to assess the association of baseline urinary metal levels with baseline CAC and cumulative change in CAC over a 10-year period. Urinary metals (μg/g creatinine) and CAC were log transformed. Models were adjusted for baseline sociodemographic factors, estimated glomerular filtration rate, lifestyle factors, and clinical factors.

RESULTS

At baseline, the median CAC was 6.3 (Q1-Q3: 0.7-58.2). Comparing the highest to lowest quartile of urinary cadmium, CAC levels were 51% (95% CI: 32%, 74%) higher at baseline and 75% (95% CI: 47%, 107%) higher over the 10-year period. For urinary tungsten, uranium, and cobalt, the corresponding CAC levels over the 10-year period were 45% (95% CI: 23%, 71%), 39% (95% CI: 17%, 64%), and 47% (95% CI: 25%, 74%) higher, respectively, with no difference for models with and without adjustment for clinical factors. For copper and zinc, the corresponding estimates dropped from 55% to 33% and from 85% to 57%, respectively, after adjustment for clinical factors. The associations of metals with CAC were comparable in magnitude to those for classical CVD risk factors.

CONCLUSIONS

Exposure to metals was generally associated with extent of coronary calcification at baseline and follow-up. These findings support that metals are associated with the progression of atherosclerosis, potentially providing a novel strategy for the prevention and treatment of atherosclerosis progression.

Aortic Aneurysm with and without Dissection and Concomitant Atherosclerosis-Differences in a Retrospective Study

BACKGROUND

Thoracic aortic aneurysm is a latent disease with a high risk of death. Today, as data are accumulating, an estimation of the differences in thoracic aneurysm in men and women of different age groups is required. The present study evaluated the type of atherosclerotic aortic lesions in males and females at different ages regarding the presence or absence of aortic dissection.

METHODS

A retrospective analysis of clinical and morphological data of 43 patients with thoracic aortic aneurysm was carried out. Patients were divided into groups based on the presence or absence of thoracic aneurysm dissection.

RESULTS

Our results of a comparative analysis of the age of study participants showed that patients with aneurysm dissection were younger than patients without dissection. In the subgroup of patients with aortic dissection, the mean age was 50.6 years old, and in patients without aortic dissection, the mean age was 55.0 years old. When conducting a frequency analysis using Fisher's exact test, it was found that in men and women aneurysm dissection was not associated with atherosclerotic lesions of the aorta.

CONCLUSIONS

In women and men, aneurysm dissection was not associated with stage of atherosclerotic lesions of the aorta regardless of age; no statistically significant differences were found between the groups with and without aneurysm dissection (p > 0.05). Dissection of the thoracic aneurysm developed in the absence of severe atherosclerosis of the thoracic aorta. Only 18.6% men and women possessed atherosclerotic plaques of types IV and V.

Diagnostic accuracy of carotid plaque magnetic resonance imaging compared to histopathology in symptomatic carotid artery stenosis

INTRODUCTION

Vulnerable plaques have been shown to predict ipsilateral cerebral ischemic events and identifying them leads to appropriate secondary stroke prevention strategies. We evaluated the diagnostic accuracy of MR carotid plaque imaging in identifying plaque vulnerability when compared with histopathological findings in patients with symptomatic carotid stenosis who underwent carotid endarterectomy (CEA).

METHODS

A prospective cohort of forty-five consecutive patients with moderate to severe symptomatic carotid stenosis who underwent CEA at a tertiary Indian hospital had 3 T MRI plaque imaging with multi-parametric protocol between November 2021 and December 2022. Images were analyzed by a vascular radiologist blinded to histopathological data. High-risk plaque characteristics such as lipid rich necrotic core (LRNC), intraplaque hemorrhage (IPH), thin fibrous cap and ulceration were assessed and correlated with histopathological findings as per American Heart Association (AHA) classification using Cohen's kappa statistics to obtain diagnostic accuracies.

RESULTS

Of the 45 patients, 38(84 %) were males. The mean age was 65 ± 7.7 years and mean duration to CEA from the most recent event was 57 days (57 ± 46 days). A significant correlation between MR plaque imaging and histopathology was noted for IPH (sensitivity-91 %, specificity-86 %, κ = 0.774, p < 0.001), LRNC (sensitivity-92.1 %, specificity-85.7 %, κ = 0.697, p < 0.001), and plaque ulceration (sensitivity-84.6 %, specificity-78.1 %, κ = 0.563, p < 0.001). MRI had an overall sensitivity and specificity of 92.3 % and 84.2 % respectively (κ = 0.77, p < 0.001) in discriminating high risk plaques.

CONCLUSION

MR plaque imaging shows a very good correlation with histopathology and can identify unstable high-risk plaques with high accuracy. This may have implication in selection of patients for carotid revascularization in symptomatic carotid stenosis.

Lipids associated with atherosclerotic plaque instability revealed by mass spectrometry imaging of human carotid arteries

BACKGROUND AND AIMS

Lipids constitute one of the main components of atherosclerosis lesions and are the mediators of many mechanisms involved in plaque progression and stability. Here we tested the hypothesis that lipids known to be involved in plaque development exhibited associations with plaque vulnerability. We used spatial lipidomics to overcome plaque heterogeneity and to compare lipids from specific regions of symptomatic and asymptomatic human carotid atherosclerotic plaques.

METHODS

Carotid atherosclerotic plaques were collected from symptomatic and asymptomatic patients. Plaque lipids were analyzed with the spatial lipidomics technique matrix-assisted laser desorption/ionization mass spectrometry imaging, and histology and immunofluorescence were used to segment the plaques into histomolecularly distinct regions.

RESULTS

Macrophage-rich regions from symptomatic lesions were found to be enriched in phosphatidylcholines (synthesized to counteract excess free cholesterol), while the same region from asymptomatic plaques were enriched in polyunsaturated cholesteryl esters and triglycerides, characteristic of functional lipid droplets. Vascular smooth muscle cells (VSMCs) of the fibrous cap of asymptomatic plaques were enriched in lysophosphatidylcholines and cholesteryl esters, know to promote VSMC proliferation and migration, crucial for the buildup of the fibrous cap stabilizing the plaque.

CONCLUSIONS

The investigation of the region-specific lipid composition of symptomatic and asymptomatic human atherosclerotic plaques revealed specific lipid markers of plaque outcome, which could be linked to known biological characteristics of stable plaques.

Non-Coding RNA Involved in the Pathogenesis of Atherosclerosis-A Narrative Review

Atherosclerosis is a highly prevalent condition associated with lipid accumulation in the intima layer of arterial blood vessels. The development of atherosclerotic plaques is associated with the incidence of major cardiovascular events, such as acute coronary syndrome or ischemic stroke. Due to the significant prevalence of atherosclerosis and its subclinical progression, it is associated with severe and potentially lethal complications. The pathogenesis of atherosclerosis is complex and not entirely known. The identification of novel non-invasive diagnostic markers and treatment methods that could suppress the progression of this condition is highly required. Non-coding RNA (ncRNA) involves several subclasses of RNA molecules. microRNA (miRNA), long non-coding RNA (lncRNA), and circular RNA (circRNA) differently regulate gene expression. Importantly, these molecules are frequently dysregulated under pathological conditions, which is associated with enhanced or suppressed expression of their target genes. In this review, we aim to discuss the involvement of ncRNA in crucial mechanisms implicated in the pathogenesis of atherosclerosis. We summarize current evidence on the potential use of these molecules as diagnostic and therapeutic targets.

Flow shear force destabilizes carotid plaques by affecting CHOP and GRP78 proteins

BACKGROUND

Various factors, including blood, inflammatory, infectious, and immune factors, can cause ischemic stroke. However, the primary cause is often the instability of cervical arteriosclerosis plaque. It is estimated that 18-25% of ischemic strokes are caused by the rupture of carotid plaque.1 Plaque stability is crucial in determining patient prognosis. Developing a highly accurate, non-invasive, or minimally invasive technique to assess carotid plaque stability is crucial for diagnosing and treating stroke.Previous research by our group has demonstrated that the expression levels of CHOP (C/EBP homologous protein) and GRP78 (glucose-regulated protein 78) are correlated with the stability of atherosclerotic plaques.2 OBJECT: This research assesses changes in GRP78 and CHOP expressions in human umbilical vein endothelial cells(HUVEC) following experiments within the hemodynamic influencing factors test system. Additionally, it includes conducting an empirical study on the impact of blood flow shear force on the stability of human carotid atherosclerotic plaques. The objective is to explore the implications of blood flow shear force on the stability of carotid atherosclerotic plaques.

METHOD

The hemodynamic influencing factors test bench system was configured with low (Group A, 4 dyns/cm²), medium (Group B, 8 dyns/cm²), and high shear force groups (Group C, 12 dyns/cm²). Relative expression levels of GRP78 and CHOP proteins in human umbilical vein endothelial cells were measured using Western blot analysis, and quantitative analysis of GRP78 and CHOP mRNA was conducted using RT-qPCR. Meanwhile, plaques from 60 carotid artery patients, retrieved via Carotid Endarterectomy (CEA), were classified into stable (S) and unstable (U) groups based on pathological criteria. Shear force at the carotid bifurcation was measured preoperatively using ultrasound. Western blot and RT-qPCR were used to analyze the relative expression levels of GRP78 and CHOP proteins and mRNA, respectively, in the plaque specimens from both groups.

RESULT

Expression levels of GRP78, CHOP proteins, and their mRNAs were assessed in groups A, B, and C via Western blot and RT-qPCR. Results showed that in the low-shear group, all markers were elevated in group A compared to groups B and C. Statistical analysis revealed significantly lower shear forces at the carotid bifurcation in group U compared to group S. In group U plaques, GRP78 and CHOP expressions were significantly higher in group U than in group S.

CONCLUSION

Blood flow shear forces variably affect the expression of GRP78 and CHOP proteins, as well as their mRNA levels, in vascular endothelial cells. The lower the shear force and fluid flow rate, the higher the expression of GRP78 and CHOP, potentially leading to endoplasmic reticulum stress(ERS), which may destabilize the plaque.

An Unsupervised Learning Tool for Plaque Tissue Characterization in Histopathological Images

Stroke is the second leading cause of death and a major cause of disability around the world, and the development of atherosclerotic plaques in the carotid arteries is generally considered the leading cause of severe cerebrovascular events. In recent years, new reports have reinforced the role of an accurate histopathological analysis of carotid plaques to perform the stratification of affected patients and proceed to the correct prevention of complications. This work proposes applying an unsupervised learning approach to analyze complex whole-slide images (WSIs) of atherosclerotic carotid plaques to allow a simple and fast examination of their most relevant features. All the code developed for the present analysis is freely available. The proposed method offers qualitative and quantitative tools to assist pathologists in examining the complexity of whole-slide images of carotid atherosclerotic plaques more effectively. Nevertheless, future studies using supervised methods should provide evidence of the correspondence between the clusters estimated using the proposed textural-based approach and the regions manually annotated by expert pathologists.

Redefining the exact roles and importance of carotid intima-media thickness and carotid plaque thickness in predicting cardiovascular events

OBJECTIVE

The survey aimed to evaluate the precise roles and importance of carotid plaque thickness and carotid intima-media thickness measured in plaque-free areas (PF CC-IMTmean) in future cardiovascular risk prediction.

MATERIAL AND METHODS

188 respondents between the age of 46 and 87 divided into two groups (I group - 94 respondents without plaques with CIMT measurement and II Group 94 respondents with carotid plaques; 118 men and 70 women; mean age ± SD, 61.80 ± 5.49) were prospectively examined by the carotid ultrasound Doppler (carotid measurements included plaque thickness PT - nonstenotic plaques (carotid stenosis <50%) and stenotic culprit plaques (carotid stenosis ≥50%), mean CIMT and maximum CIMT). Subjects were followed for 36 months from the inclusion in the study (regular control examinations). Data were recorded on new cases of mortality (CV mortality) and adverse CV events (myocardial infarction - -MI, surgical or endovascular revascularization - coronary or stroke).

RESULTS

In this study, CIMT values vary between 0.62 and 1.43 mm (mean CIMT = 1.21 ± 0.2 mm) while 52 subjects had nonstenotic plaques (14 respondents plaque ulceration, 22 type 2 diabetes mellitus, 38 arterial hypertension) and 38 subjects had stenotic culprit plaques (17 respondents plaque ulceration, 20 type 2 diabetes mellitus, 31 arterial hypertension). After 36 months of follow-up, 76 vascular events were noted (MI, transient ischaemic attack - TIA, stroke and cardiovascular angioplasty or surgery) in this period.

CONCLUSION

Respondents with carotid plaques had higher cardiovascular events occurrence (p < .01, high statistical difference). Carotid plaques as a parameter have higher predictive vascular event value importance than CIMT. Of note, stenotic plaques, the presence of ulceration on the free surface of the plaque, type 2 diabetes mellitus and hypertension were connected with the highest events occurrence.

Efficient and Accurate 3D Thickness Measurement in Vessel Wall Imaging: Overcoming Limitations of 2D Approaches Using the Laplacian Method

The clinical significance of measuring vessel wall thickness is widely acknowledged. Recent advancements have enabled high-resolution 3D scans of arteries and precise segmentation of their lumens and outer walls; however, most existing methods for assessing vessel wall thickness are 2D. Despite being valuable, reproducibility and accuracy of 2D techniques depend on the extracted 2D slices. Additionally, these methods fail to fully account for variations in wall thickness in all dimensions. Furthermore, most existing approaches are difficult to be extended into 3D and their measurements lack spatial localization and are primarily confined to lumen boundaries. We advocate for a shift in perspective towards recognizing vessel wall thickness measurement as inherently a 3D challenge and propose adapting the Laplacian method as an outstanding alternative. The Laplacian method is implemented using convolutions, ensuring its efficient and rapid execution on deep learning platforms. Experiments using digital phantoms and vessel wall imaging data are conducted to showcase the accuracy, reproducibility, and localization capabilities of the proposed approach. The proposed method produce consistent outcomes that remain independent of centerlines and 2D slices. Notably, this approach is applicable in both 2D and 3D scenarios. It allows for voxel-wise quantification of wall thickness, enabling precise identification of wall volumes exhibiting abnormal wall thickness. Our research highlights the urgency of transitioning to 3D methodologies for vessel wall thickness measurement. Such a transition not only acknowledges the intricate spatial variations of vessel walls, but also opens doors to more accurate, localized, and insightful diagnostic insights.

TNF Induces Laminin-332-Encoding Genes in Endothelial Cells and Laminin-332 Promotes an Atherogenic Endothelial Phenotype

Laminins are essential components of the basement membranes, expressed in a tissue- and cell-specific manner under physiological conditions. During inflammatory circumstances, such as atherosclerosis, alterations in laminin composition within vessels have been observed. Our study aimed to assess the influence of tumor necrosis factor-alpha (TNF), a proinflammatory cytokine abundantly found in atherosclerotic lesions, on endothelial laminin gene expression and the effects of laminin-332 (LN332) on endothelial cells' behavior. We also evaluated the expression of LN332-encoding genes in human carotid atherosclerotic plaques. Our findings demonstrate that TNF induces upregulation of LAMB3 and LAMC2, which, along with LAMA3, encode the LN332 isoform. Endothelial cells cultured on recombinant LN332 exhibit decreased claudin-5 expression and display a loosely connected phenotype, with an elevated expression of chemokines and leukocyte adhesion molecules, enhancing their attractiveness and adhesion to leukocytes in vitro. Furthermore, LAMB3 and LAMC2 are upregulated in human carotid plaques and show a positive correlation with TNF expression. In summary, TNF stimulates the expression of LN332-encoding genes in human endothelial cells and LN332 promotes an endothelial phenotype characterized by compromised junctional integrity and increased leukocyte interaction. These findings highlight the importance of basement membrane proteins for endothelial integrity and the potential role of LN332 in atherosclerosis.

Impact of the ketogenic diet as a dietary approach on cardiovascular disease risk factors: a meta-analysis of randomized clinical trials

BACKGROUND

Cardiovascular diseases (CVD) remain the leading cause of mortality globally, and the scarcity of scientific evidence regarding the impact of ketogenic diets on CVD risk factors necessitates urgent attention and redress.

OBJECTIVES

This meta-analysis evaluates the impact of the ketogenic diet on CVD risk factors compared with control diets through randomized controlled trials (RCTs).

METHODS

The study was registered in advance in the PROSPERO database (CRD42023491853). A systematic search was conducted across PubMed, Web of Science, EMBASE, and Cochrane Library to identify relevant RCTs. Fixed and random effects were employed to calculate the mean differences and 95% confidence intervals (CIs) for changes in CVD risk factors pre- and postketogenic diet intervention.

RESULTS

A total of 27 RCTs with 1278 participants were analyzed. The ketogenic diet intervention presented increase in total cholesterol (mean differences: 0.36 mmol/L; 95% CI: 0.15, 0.57; I2: 85.1%), low-density lipoprotein cholesterol (mean differences: 0.35 mmol/L; 95% CI: 0.20, 0.50; I2: 73.9%) and high-density lipoprotein cholesterol (mean differences: 0.16 mmol/L; 95% CI: 0.09, 0.23; I2: 86.7%) concentrations. Reductions were observed in the triglyceride (mean differences: -0.20 mmol/L; 95% CI: -0.29, -0.11; I2: 72.2%), blood glucose (mean differences: -0.18 mmol/L; 95% CI: -0.33, -0.02; I2: 76.4%), blood insulin (mean differences: -8.32 pmol/L; 95% CI: -14.52, -2.12; I2: 81.5%), diastolic blood pressure (mean differences: -1.41 mmHg; 95% CI: -2.57, -0.26; I2: 49.1%), weight (mean differences: -2.59 kg; 95% CI: -3.90, -1.28; I2: 87.4%), and body mass index (mean differences: -1.59 kg/m2; 95% CI: -2.32, -0.86; I2: 84.5%) concentrations after implementing ketogenic diets.

CONCLUSIONS

Although the ketogenic diet demonstrates benefits in terms of triglyceride, blood pressure, weight, and glycemic control, its impact on CVD risk factors, especially the elevated total cholesterol and low-density lipoprotein cholesterol concentrations, warrants a cautious approach.

Exogenous Growth Hormone Exacerbates Post-Irradiation Atherosclerosis in Susceptible Epicardial Coronary Arteries

Cardiac exposure to ionizing radiation can damage both the microvasculature and coronary arteries, as well as increase the long-term risk of heart disease, myocardial fibrosis, and conduction abnormalities. Therapeutic agents capable of promoting recovery from radiation injury to the heart are limited. Growth hormone is linked to improved cardiac function following injury. Here, we leveraged a cynomolgus macaque model to determine the long-term outcomes of recombinant human growth hormone (rhGH) therapy on the heart following low-dose ionizing radiation. Macaques were exposed to 2 Gy radiation, treated with rhGH for one month, and assessed after 2 years. Overall, plasma lipid profile, cardiac function, and coronary artery disease were similar between rhGH and placebo treated animals. However, a subgroup of rhGH-treated animals exhibited more extensive atherosclerotic plaques in the coronary arteries. Together, these findings indicate that transient human growth hormone therapy subsequent to a single low dose of ionizing radiation involving the heart does not result in long-term changes to plasma cholesterol but may promote exacerbated coronary artery disease in a subset of individuals.

MiR-127-3p enhances macrophagic proliferation via disturbing fatty acid profiles and oxidative phosphorylation in atherosclerosis

BACKGROUND

Atherosclerosis is a chronic pathology, leading to acute coronary heart disease or stroke. MiR-127 has been found significantly upregulated in advanced atherosclerosis. But its function in atherosclerosis remains unexplored. We explored the role of miR-127-3p in regulating atherosclerosis development and its downstream mechanisms.

METHODS

The expression profile of miR-127 in carotid atherosclerotic plaques of 23 patients with severe carotid stenosis was detected by RT-qPCR and in situ hybridization. Primary bone marrow-derived macrophages (BMDM) stimulated with oxidized low-density lipoprotein were used as an in vitro model. CCK-8, EdU, RT-qPCR, and flow cytometry were used to detect the proliferative capacity and polarization of BMDM, which were infected by lentivirus-carrying plasmid to upregulate or downregulate miR-127-3p expression, respectively. RNA sequencing combined with bioinformatic analysis and targeted fatty acid metabolomics approach were used to detect the transcriptome and lipid metabolites. The association between miR-127-3p and its target was verified by dual-luciferase activity reporting and Western blotting. Oxygen consumption rate of BMDM were detected using seahorse analysis. High-cholesterol-diet-fed low density lipoprotein deficient (LDLR-/-) mice, with-or-without carotid tandem-stenosis surgery, were treated with miR-127-3p agomir or antagomir to examine its effect on plaque development and stability.

RESULTS

miR-127-3p, not -5p, is elevated in human advanced carotid atheroma and its expression is positively associated with macrophage accummulation in plaques. In vitro, miR-127-3p-overexpressed macrophage exhibites increased proliferation capacity and facilitates M1 polariztion whereas the contrary trend is present in miR-127-3p-inhibited macrophage. Stearoyl-CoA desaturase-1 (SCD1) is one potential target of miR-127-3p. miR-127-3p mimics decreases the activity of 3' untranslated regions of SCD-1. Furthermore, miR-127-3p downregulates SCD1 expression, and reversing the expression of SCD1 attenuates the increased proliferation induced by miR-127-3p overexpression in macrophage. miR-127-3p overexpression could also lead to decreased content of unsaturated fatty acids (UFAs), increased content of acetyl CoA and increased level of oxidative phosphorylation. In vivo, miR-127-3p agomir significantly increases atherosclerosis progression, macrophage proliferation and decreases SCD1 expression and the content of UFAs in aortic plaques of LDLR-/- mice. Conversely, miR-127-3p antagomir attenuated atherosclerosis, macrophage proliferation in LDLR-/- mice, and enhanced carotid plaque stability in mice with vulnerable plaque induced.

CONCLUSION

MiR-127-3p enhances proliferation in macrophages through downregulating SCD-1 expression and decreasing the content of unsaturated fatty acid, thereby promoting atherosclerosis development and decreasing plaque stability. miR-127-3p/SCD1/UFAs might provide potential therapeutic target for anti-inflammation and atherosclerosis.

Elevated heart rate and decreased muscle endothelial nitric oxide synthase in early development of insulin resistance

Insulin resistance (IR) is a risk factor for the development of several major metabolic diseases. Muscle fiber composition is established early in life and is associated with insulin sensitivity. Hence, muscle fiber composition was used to identify early defects in the development of IR in healthy young individuals in the absence of clinical manifestations. Biopsies were obtained from the thigh muscle, followed by an intravenous glucose tolerance test. Indices of insulin action were calculated and cardiovascular measurements, analyses of blood and muscle were performed. Whole body insulin sensitivity (SIgalvin) was positively related to expression of type I muscle fibers (r = 0.49; P < 0.001) and negatively related to resting heart rate (HR, r = -0.39; P < 0.001), which was also negatively related to expression of type I muscle fibers (r = -0.41; P < 0.001). Muscle protein expression of endothelial nitric oxide synthase (eNOS), whose activation results in vasodilation, was measured in two subsets of subjects expressing a high percentage of type I fibers (59 ± 6%; HR = 57 ± 9 beats/min; SIgalvin = 1.8 ± 0.7 units) or low percentage of type I fibers (30 ± 6%; HR = 71 ± 11; SIgalvin = 0.8 ± 0.3 units; P < 0.001 for all variables vs. first group). eNOS expression was 1) higher in subjects with high type I expression; 2) almost twofold higher in pools of type I versus II fibers; 3) only detected in capillaries surrounding muscle fibers; and 4) linearly associated with SIgalvin. These data demonstrate that an altered function of the autonomic nervous system and a compromised capacity for vasodilation in the microvasculature occur early in the development of IR.NEW & NOTEWORTHY Insulin resistance (IR) is a risk factor for the development of several metabolic diseases. In healthy young individuals, an elevated heart rate (HR) correlates with low insulin sensitivity and high expression of type II skeletal muscle fibers, which express low levels of endothelial nitric oxide synthase (eNOS) and, hence, a limited capacity to induce vasodilation in response to insulin. Early targeting of the autonomic nervous system and microvasculature may attenuate development of diseases stemming from insulin resistance.

Myocardial Bridge and Atherosclerosis, an Intimal Relationship

PURPOSE OF REVIEW

This review investigates the relationship between myocardial bridges (MBs), intimal thickening in coronary arteries, and Atherosclerotic cardiovascular disease. It focuses on the role of mechanical forces, such as circumferential strain, in arterial wall remodeling and aims to clarify how MBs affect coronary artery pathology.

REVIEW FINDINGS

MBs have been identified as influential in modulating coronary artery intimal thickness, demonstrating a protective effect against thickening within the MB segment and an increase in thickness proximal to the MB. This is attributed to changes in mechanical stress and hemodynamics. Research involving arterial hypertension models and vein graft disease has underscored the importance of circumferential strain in vascular remodeling and intimal hyperplasia. Understanding the complex dynamics between MBs, mechanical strain, and vascular remodeling is crucial for advancing our knowledge of coronary artery disease mechanisms. This could lead to improved management strategies for cardiovascular diseases, highlighting the need for further research into MB-related vascular changes.

Oxidized LDL regulates efferocytosis through the CD36-PKM2-mtROS pathway

Macrophage efferocytosis, the process by which phagocytes engulf and remove apoptotic cells (ACs), plays a critical role in maintaining tissue homeostasis. Efficient efferocytosis prevents secondary necrosis, mitigates chronic inflammation, and impedes atherosclerosis progression. However, the regulatory mechanisms of efferocytosis under atherogenic conditions remain poorly understood. We previously demonstrated that oxidized LDL (oxLDL), an atherogenic lipoprotein, induces mitochondrial reactive oxygen species (mtROS) in macrophages via CD36. In this study, we demonstrate that macrophage mtROS facilitate continual efferocytosis through a positive feedback mechanism. However, oxLDL disrupts continual efferocytosis by dysregulating the internalization of ACs. This disruption is mediated by an overproduction of mtROS. Mechanistically, oxLDL/CD36 signaling promotes the translocation of cytosolic PKM2 to mitochondria, facilitated by the chaperone GRP75. Mitochondrial PKM2 then binds to Complex III of the electron transport chain, inducing mtROS production. This study elucidates a novel regulatory mechanism of efferocytosis in atherosclerosis, providing potential therapeutic targets for intervention.

SUMMARY

Macrophages clear apoptotic cells through a process called efferocytosis, which involves mitochondrial ROS. However, the atherogenic oxidized LDL overstimulates mitochondrial ROS via the CD36-PKM2 pathway, disrupting continual efferocytosis. This finding elucidates a novel molecular mechanism that explains defects in efferocytosis, driving atherosclerosis progression.

Donor Atheromatous Disease is a Risk Factor for Hepatic Artery Thrombosis After Liver Transplantation

The increasing age of liver donors and transplant candidates, together with the growing prevalence of metabolic comorbidities, could impact the risk of vascular complications after liver transplantation. We enrolled a consecutive cohort of adult patients undergoing liver transplantation from 2012 to 2021 who had a blinded pathological assessment of atherosclerosis in the donor and recipient hepatic arteries (HA). Patients receiving partial or reduced grafts, retransplantation, or combined organ transplantation were excluded. The relationship between HA atherosclerosis and HA thrombosis after liver transplantation was evaluated using logistic regression in the whole study cohort and in a propensity score-matched subpopulation. Among 443 eligible patients, 272 had a full pathological evaluation of the donor and recipient HA and were included in the study. HA atheroma was present in 51.5% of donors and in 11.4% of recipients. HA thrombosis occurred in 16 patients (5.9%), being more likely in patients who received a donor with HA atherosclerosis than in those without (10.7% vs. 0.8%; p < 0.001). Donor HA atherosclerosis was an independent risk factor of HA thrombosis (OR = 17.79; p = 0.008), and this finding was consistent in the propensity score-matched analysis according to age, sex, complex arterial anastomosis, and alcoholic liver disease (OR = 19.29; p = 0.007). Atheromatous disease in the recipient had no influence on the risk of HA thrombosis (OR = 1.70; p = 0.55). In conclusion, patients receiving donors with HA atherosclerosis are at increased risk for HA thrombosis after liver transplantation. The evaluation of the donor graft vasculature could guide antiplatelet therapy in the postoperative period.