Initiation Of Atherosclerosis Research Articles

The Complexity of Premature Coronary Artery Disease

Premature Coronary Artery Disease presents a significant health concern globally, characterized by the onset of coronary atherosclerosis at an early age, typically before the age of 55 in men and 65 in women. This review provides a comprehensive examination of the various aspects of premature CAD, ranging from its underlying pathophysiology to diagnostic modalities such as coronary angiography. Beginning with an overview of the risk factors contributing to premature CAD, including genetic predispositions, lifestyle factors, and metabolic disorders, the review delves into the intricate mechanisms involved in the initiation and progression of atherosclerosis. Furthermore, the review discusses the clinical manifestations and challenges associated with diagnosing premature CAD, particularly in asymptomatic individuals. It examines the utility of non-invasive imaging techniques, stress testing in identifying coronary artery stenosis, cardiovascular risk and the principles of coronary angiography. The review outlines the principles of coronary angiography, including patient preparation, procedural techniques, and interpretation of angiographic findings. In conclusion, this comprehensive review provides insights into the multifaceted nature of premature CAD, elucidating its pathogenesis, clinical presentation, and diagnostic evaluation, with a focus on the pivotal role of coronary angiography in guiding therapeutic interventions and optimizing patient outcomes. Keyword: Coronary Angiography, Premature Coronary Artery Disease, Risk Factor.

MCP-1 rs1024611 Polymorphism, MCP-1 Concentrations, and Premature Coronary Artery Disease: Results of the Genetics of Atherosclerotic Disease (GEA) Mexican Study.

Monocyte chemoattractant protein-1 (MCP-1) participates in the initiation and progression of atherosclerosis. In vitro studies have reported that the MCP-1 rs1024611 polymorphism is associated with increased MCP-1 concentrations. The study aimed to define whether MCP-1 concentrations are associated with premature coronary artery disease (pCAD) and to establish whether variations in the rs1024611 polymorphism increase MCP-1 concentrations. MCP-1 rs1024611 polymorphism was determined in 972 pCAD patients and 1070 control individuals by real-time PCR. MCP-1 concentrations were determined by the Bio-Plex system. In the total population, men had higher MCP-1 concentrations when compared to women (p < 0.001). When stratified by rs1024611 genotypes, higher MCP-1 concentrations were observed in AA individuals compared to GG subjects (p = 0.023). When performing the analysis considering sex, the differences remained significant in women (AA vs. GG, p = 0.028 and GA vs. GG, p = 0.008). MCP-1 concentrations were similar in pCAD patients and controls (p = 0.782). However, the independent analysis of the studied groups showed that in patients with the AA genotype, MCP-1 concentrations were significantly higher when compared to patients with the GG genotype (p = 0.009). Considering that the AA genotype increases MCP-1 concentration, we evaluated whether, in AA genotype carriers, MCP-1 concentrations were associated with pCAD. The results showed that for every ten pg/mL increase in MCP-1 concentration, the risk of presenting pCAD increases by 2.7% in AA genotype individuals. Individuals with the MCP-1 rs1024611 AA genotype present an increase in MCP-1 concentration. In those individuals, increased MCP-1 concentrations increase the risk of presented pCAD.

Exploring the relationship between hemodynamics and the immune microenvironment in carotid atherosclerosis: Insights from CFD and CyTOF technologies.

Carotid atherosclerosis is a major cause of stroke. Hemodynamic forces, such as shear stress and oscillatory shear, play an important role in the initiation and progression of atherosclerosis. The alteration of the immune microenvironment is the fundamental pathological mechanism by which diverse external environmental factors impact the formation and progression of plaques. However, Current research on the relationship between hemodynamics and immunity in atherosclerosis still lack of comprehensive understanding. In this study, we combined computational fluid dynamics (CFD) and Mass cytometry (CyTOF) technologies to explore the changes in the immune microenvironment within plaques under different hemodynamic conditions. Our results indicated that neutrophils were enriched in adverse flow environments. M2-like CD163+CD86+ macrophages were predominantly enriched in high WSS and low OSI environments, while CD163-CD14+ macrophages were enriched in low WSS and high OSI environments. Functional analysis further revealed T cell pro-inflammatory activation and dysregulation in modulation, along with an imbalance in M1-like/M2-like macrophages, suggesting their potential involvement in the progression of atherosclerotic lesions mediated by adverse flow patterns. Our study elucidated the potential mechanisms by which hemodynamics regulated the immune microenvironment within plaques, providing intervention targets for future precision therapies.

Abstract 3070: Investigating CD36 Oligomerization In Macrophages

Cardiovascular disease (CVD) is the leading cause of mortality worldwide. Atherosclerosis, the main cause of CVD, results from the buildup of cholesterol-filled plaques in artery walls. Accumulation of cholesterol from oxidized low-density lipoprotein (oxLDL) leads to the formation of macrophage foam cells, a process that is mediated by CD36, a scavenger receptor that serves as the primary receptor for oxLDL. The structure of full-length CD36 has not been resolved, nor have the details or role of quaternary structure been fully elucidated. Studies have shown that CD36 has the ability to form homodimers and multimers in some cell types. However, the role of CD36 oligomerization in oxLDL uptake remains unknown. The goal of this study is to investigate CD36 oligomerization in macrophages, a cell type important in the initiation of atherosclerosis. We hypothesize that CD36 oligomerizes in macrophages to facilitate oxLDL uptake. To begin testing this hypothesis, we harvested elicited peritoneal macrophages from wild-type (WT) or CD36 knockout (CD36-KO) mice. We performed crosslinking experiments in which macrophages were incubated with BS3, a membrane-impermeable crosslinker, to stabilize CD36 oligomers. When crosslinked samples were separated by SDS-PAGE electrophoresis, we observed a decrease in monomeric species with increasing crosslinker concentration, however, BS3 also induced aggregation of CD36 rather than oligomer formation. We next turned to Native-PAGE electrophoresis, which lacks detergent entirely, to identify oligomeric species within macrophages, as well as PFO-PAGE electrophoresis, which contains a milder detergent than SDS. Both methods provided evidence of higher-order complexes in WT, but not in CD36-KO macrophages. To further validate our studies, we purified human full-length CD36 using an Sf9 insect cell system and demonstrated that pure CD36 forms homo-oligomers by PFO-PAGE. Together, these experiments provide strong evidence for CD36 oligomerization. Future studies will focus on correlating CD36 oligomerization with its functions in oxLDL binding and uptake. Understanding the higher-order structure of CD36 and how it impacts function will allow us to target CD36 to prevent foam cell formation and atherosclerosis.

Impact of Platelet-to-HDL-Cholesterol Ratio on Long-Term Mortality in Coronary Artery Disease Patients with or Without Type 2 Diabetes: Insights from a Chinese Multicenter Cohort.

Inflammation contributes to the initiation and advancement of both coronary atherosclerosis and type 2 diabetes mellitus (T2DM). Recent evidence has underscored the platelet-to-HDL-cholesterol ratio (PHR) as a promising inflammatory biomarker closely linked to the severity of coronary artery disease (CAD). Nevertheless, the risk of adverse clinical outcomes remains unclear among CAD patients with varying PHR levels and glycemic status. A total of 56,316 CAD patients were enrolled, primarily focusing on mortality outcomes. Patients were categorized into four subgroups based on median baseline PHR values and glycemic status: lower PHR (PHR-L) and higher PHR (PHR-H) with or without T2DM. Cox proportional hazard model and subgroup analysis were employed to investigate the association between PHR and glycemic status with mortality. Over a median 5.32-year follow-up, 8909 (15.8%) patients experienced all-cause mortality, with 3873 (6.9%) deaths attributed to cardiovascular causes. Compared to individuals in PHR-L/non-DM, those in PHR-H/non-DM, PHR-L/DM and PHR-H/DM groups exhibited a higher risk of all-cause death [adjusted hazard ratio (HR) 1.12, 95% confidence interval (CI) 1.06-1.18; HR 1.21, 95% CI 1.14-1.29; HR 1.43, 95% CI 1.34-1.52, respectively], as well as cardiac mortality [HR 1.19, 95% CI 1.08-1.30; HR 1.58, 95% CI 1.44-1.74; HR 1.89, 95% CI 1.72-2.07, respectively]. Cox proportional hazard model also revealed the highest mortality risk among patients in PHR-H/DM compared to other groups (P <0.05). Restricted cubic spline regression analysis revealed a positive linear association between PHR and all-cause as well as cardiac mortality (P for non-linearity >0.05) after adjustment. Additionally, subgroup analysis indicated consistent effects on cardiac mortality within diverse subsets. In this real-world observational cohort analysis, elevated PHR levels joint with T2DM were related to adverse long-term clinical outcomes in CAD patients. PHR levels may serve as a valuable tool for identifying high-risk individuals within this specific group. The Cardiorenal ImprovemeNt II registry NCT05050877.

Abstract 1036: Mechanisms Of Foamy Monocyte Formation In Atherosclerosis

Diseases linked to atherosclerosis are the leading cause of death in the United States. Transmigration of monocytes across the endothelial layer and their differentiation into macrophages play an important role in the initiation and progression of atherosclerosis. These monocyte-derived macrophages internalize modified LDL in the arterial wall and drive the pathogenesis of atherosclerosis. Recent studies have shown that pharmacological depletion of foamy monocytes inhibits atherosclerosis development in mice, identifying monocyte uptake of plasma LDL as a therapeutic target in atherosclerosis. However, the precise mechanisms by which monocytes internalize plasma LDL remain unknown. The goal of our study was to investigate the role, and relative contribution, of macropinocytosis and scavenger receptors ( Cd36 and Sr-a ) to foamy monocyte formation. The presence of foamy monocytes was confirmed in hypercholesterolemic mice and humans via flow cytometry analysis of Nile Red fluorescence. High resolution scanning electron microscopy and flow cytometry analysis of dextran internalization confirmed macropinocytosis stimulation in THP-1 and primary murine monocytes. Stimulation of macropinocytosis in monocytes induced uptake of both native LDL and oxLDL, leading to foamy monocyte formation in vitro . Pharmacological (EIPA) and genetic inhibition of macropinocytosis ( Lysm - CreER T2+/- Nhe1 -/- ) inhibited foamy monocyte formation (58.9%) in hypercholesterolemic mice in vivo . RT-PCR confirmed expression of Cd36 and Sr-a in monocytes and deletion of Cd36 and Sr-a inhibited foamy monocyte formation in hypercholesterolemic mice (10.3%) compared to wild type controls. FACS and bulk RNA sequencing characterized monocyte subsets including classical, intermediate, and non-classical monocytes in hypercholesterolemic Cd36 -/- / Sr-a -/- and Lysm - CreER T2+/- Nhe1 -/- mice and their respective wild type controls. Mechanistic studies identified NADPH oxidase 2 (Nox2) and downstream redox regulation of actin-cytoskeleton as a major stimulator of monocyte macropinocytosis. These results provide novel insights into the mechanisms of foamy monocyte formation and potentially identify new therapeutic targets in the treatment of atherosclerosis.

Abstract 3048: The Role Of 17:0(2r-oh) Ceramide In Lps Activated Macrophages

Macrophages play a crucial role in the initiation and progression of atherosclerosis, contributing to the buildup of fatty deposits which results in the plaque formation in the walls of arteries. Macrophages modulate the mediators of inflammation and immune response in atherosclerosis. Bacterial lipopolysaccharide (LPS) exerts significant effects on these macrophages including secretion of pro-inflammatory cytokines. The current study is designed to examine the role of sphingosine intermediate N-(2'-(R)-hydroxyheptadecanoyl)-D-erythro-sphingosine (17:0(2R-OH) in the macrophage’s inflammation potential. Couple of studies have indicated a protective role for sphingosine however 17:0(2R-OH) didn’t receive adequate attention. Study design: Mouse J774 macrophages were cultured in Dulbecco’s Modified Eagle’s medium with 4.5g/L glucose and sodium pyruvate without L-glutamine containing 10% fetal bovine serum and 1% penicillin/streptomycin in a humidified atmosphere with 5% CO 2 at 37 °C. The cells were treated in 6-well plates at a density of 5.5х10 6 cells/well. Sphingosine was dissolved in DMSO prior to the treatment. The cells were treated with the 17:0(2R-OH) with 3 different concentrations (5, 25, 50 μg) in duplicates with or without LPS except for the controls. The cells and media were collected at 3 time points (12,24,36) hours. Cells were harvested in Trizol reagent, RNA was then extracted from cells and genes expression were determined in RTPCR using SYBR Green. Results and Conclusion: Our initial microscopic observations suggest that 17:0(2R-OH) potentially modulates inflammation in macrophages, this appears to be dose-dependent. 17:0(2R-OH) has been identified in marine and freshwater fish, marine oils, seaweed, sea urchins, sea cucumbers and may have dietary benefits.

Oscillatory shear stress promotes endothelial senescence and atherosclerosis via STING activation

Endothelial dysfunction is an initiating factor in atherosclerosis. Endothelial cells (ECs) are constantly subject to blood flow shear stress, and atherosclerotic plaques tend to occur in aortic bends or bifurcations impaired by low oscillatory shear stress (OSS). However, the mechanism that how OSS affects the initiation and progression of atherosclerosis remains to be explored. Here, we first reported that OSS can promote endothelial dysfunction and atherogenesis in vivo and in vitro by activating STING pathway. Mechanistically, at atherosclerosis-prone areas, OSS caused mitochondria damage in ECs, leading to the leakage of mitochondrial DNA (mtDNA) into the cytoplasm. The cytoplasmic mtDNA was recognized by cGAS to produce cGAMP, activating the STING pathway and leading to endothelial senescence, which resulted in endothelial dysfunction and atherosclerosis. We found that STING was activated in plaques of atherosclerotic patients and in aortic arch ECs of high-fat diet (HFD)-fed ApoeKO mice, as well as in ECs exposed to OSS. STING-specific deficiency in ECs attenuates endothelial senescence and resulted in a significant reduction in aortic arch plaque area in HFD-fed ApoeKO mice. Consistently, specific deficiency or pharmacological inhibition of STING attenuated OSS-induced senescence and endothelial dysfunction. Pharmacological depletion of mtDNA ameliorated OSS-induced senescence and endothelial dysfunction. Taken together, our study linked hemodynamics and endothelial senescence, and revealed a novel mechanism by which OSS leads to endothelial dysfunction. Our study provided new insights into the development of therapeutic strategies for endothelial senescence and atherosclerosis.

Endothelial Cell-Derived Cholesterol Crystals Promote Endothelial Inflammation in Early Atherogenesis.

Endothelial inflammation is crucial in the initiation and progression of atherosclerosis, while cholesterol crystals (CCs) play a key role in atherogenesis. However, the effects and origination of CCs on endothelial inflammation are not well understood. In the present study, we found that CCs appeared in the subendothelial space of the partially ligated carotid artery only one week after western diet feeding, which was before immune cell infiltration. In vitro, CCs were generated by human aortic endothelial cells (HAECs) upon LDL treatment. These EC-derived CCs increased the expression of intercellular cell adhesion molecule-1 (ICAM1) and vascular cell adhesion molecule-1 (VCAM1). Mechanistic studies demonstrated that CC-induced pyroptosis was critical for endothelial inflammation. Knockdown of GSDMD inhibited CC-induced endothelial inflammation, attenuated plaque progression and decreased macrophage content. Accordingly, the inhibition of GSDMD reduced the CC-induced increase of VCAM1 and ICAM1 in HAECs. Furthermore, CC-mediated pyroptosis was found to be caspase-1 (CASP1) dependent. Inhibition of CASP1 also reduced endothelial inflammation and attenuated plaque progression. In addition, the expression of GSDMD was increased in human atherosclerotic plaques. These findings identify EC-derived CCs may be an important driving force in the pathogenesis of atherosclerosis. This study uncovered a new understanding that EC-derived CC-induced pyroptosis is a key initial factor in early atherogenesis. Targeting endothelial GSDMD or CASP1 contributes to the repression of vascular inflammation and atherogenesis. Targeting endothelial GSDMD or CASP1 contributes to the repression of vascular inflammation and atherogenesis.

Matrix metallopeptidase 9 contributes to the beginning of plaque and is a potential biomarker for the early identification of atherosclerosis in asymptomatic patients with diabetes.

To determine the roles of matrix metallopeptidase-9 (MMP9) on human coronary artery smooth muscle cells (HCASMCs) in vitro, early beginning of atherosclerosis in vivo in diabetic mice, and drug naïve patients with diabetes. Active human MMP9 (act-hMMP9) was added to HCASMCs and the expressions of MCP-1, ICAM-1, and VCAM-1 were measured. Act-hMMP9 (n=16) or placebo (n=15) was administered to diabetic KK.Cg-Ay/J (KK) mice. Carotid artery inflammation and atherosclerosis measurements were made at 2 and 10 weeks after treatment. An observational study of newly diagnosed drug naïve patients with type 2 diabetes mellitus (T2DM n=234) and healthy matched controls (n=41) was performed and patients had ultrasound of carotid arteries and some had coronary computed tomography angiogram for the assessment of atherosclerosis. Serum MMP9 was measured and its correlation with carotid artery or coronary artery plaques was determined. In vitro, act-hMMP9 increased gene and protein expressions of MCP-1, ICAM-1, VCAM-1, and enhanced macrophage adhesion. Exogenous act-hMMP9 increased inflammation and initiated atherosclerosis in KK mice at 2 and 10 weeks: increased vessel wall thickness, lipid accumulation, and Galectin-3+ macrophage infiltration into the carotid arteries. In newly diagnosed T2DM patients, serum MMP9 correlated with carotid artery plaque size with a possible threshold cutoff point. In addition, serum MMP9 correlated with number of mixed plaques and grade of lumen stenosis in coronary arteries of patients with drug naïve T2DM. MMP9 may contribute to the initiation of atherosclerosis and may be a potential biomarker for the early identification of atherosclerosis in patients with diabetes. https://clinicaltrials.gov, identifier NCT04424706.

The role and mechanism of the zinc finger gene ZNF580 in foam cell formation

Coronary atherosclerotic heart disease is an important threat to human health. The pathological basis is atherosclerosis, and foam cell formation is the key link in the initiation of atherosclerosis. Here, foam cell models were established using 50 ng/ml oxidized low-density lipoprotein (ox-LDL) to stimulate in vitro cultures of THP-1 cells for 72 h. The expression of ZNF580, a Cys2–His2 (C2H2) zinc finger protein containing 172 amino acids that was originally cloned by screening a human aortic cDNA library, was measured in foam cells, and its interaction with various regulatory factors during foam cell formation was investigated. Oil red O (ORO) staining was used to observe cell morphology and intracellular lipid levels. Lentivirus transfection was used to induce high ZNF580 expression (Ad-ZNF580) and low ZNF580 expression (Si-ZNF580) in THP-1 cells, and a fluorescent inverted microscope was used to observe the distribution of ZNF580 immunofluorescence to deduce the transfection rate. RNA and total protein were extracted, and the expression levels of ZNF580, cluster of differentiation 36 (CD36), peroxisome proliferator activated receptor-γ (PPAR-γ), ATP-binding cassette transporter A1 (ABCA1) and apolipoprotein E (ApoE) were measured by real-time quantitative PCR. The protein levels were examined by western blotting to evaluate the interaction between ZNF580 and associated regulatory factors. ZNF580 can significantly increase the expression levels of ApoE and ABCA1 and significantly decrease the expression levels of CD36 and PPAR-γ, suggesting that ZNF580-mediated inhibition of foam cell formation is associated with the PPAR-γ-CD36 signalling pathway. Based on these findings, ZNF580 might be a potential therapeutic candidate for the treatment of coronary atherosclerotic heart disease. Zhangzhongbai: ZNF580 inhibit foam cell formation

Heparanase promotes the onset and progression of atherosclerosis in apolipoprotein E gene knockout mice

Background and aimsAtherosclerosis is the primary underlying cause of myocardial infarction and stroke, which are the major causes of death globally. Heparanase (Hpse) is a pro-inflammatory extracellular matrix degrading enzyme that has been implicated in atherogenesis. However, to date the precise roles of Hpse in atherosclerosis and its mechanisms of action are not well defined. This study aims to provide new insights into the contribution of Hpse in different stages of atherosclerosis in vivo. MethodsWe generated Hpse gene-deficient mice on the atherosclerosis-prone apolipoprotein E gene knockout (ApoE−/−) background to investigate the impact of Hpse gene deficiency on the initiation and progression of atherosclerosis after 6 and 14 weeks high-fat diet feeding, respectively. Atherosclerotic lesion development, blood serum profiles, lesion composition and aortic immune cell populations were evaluated. ResultsHpse-deficient mice exhibited significantly reduced atherosclerotic lesion burden in the aortic sinus and aorta at both time-points, independent of changes in plasma cholesterol levels. A significant reduction in the necrotic core size and an increase in smooth muscle cell content were also observed in advanced atherosclerotic plaques of Hpse-deficient mice. Additionally, Hpse deficiency reduced circulating and aortic levels of VCAM-1 at the initiation and progression stages of disease and circulating MCP-1 levels in the initiation but not progression stage. Moreover, the aortic levels of total leukocytes and dendritic cells in Hpse-deficient ApoE−/− mice were significantly decreased compared to control ApoE−/−mice at both disease stages. ConclusionsThis study identifies Hpse as a key pro-inflammatory enzyme driving the initiation and progression of atherosclerosis and highlighting the potential of Hpse inhibitors as novel anti-inflammatory treatments for cardiovascular disease.

Breaking tolerance: the autoimmune aspect of atherosclerosis.

Atherosclerotic cardiovascular disease (ASCVD) is a chronic inflammatory disease of the arterial walls and is characterized by the accumulation of lipoproteins that are insufficiently cleared by phagocytes. Following the initiation of atherosclerosis, the pathological progression is accelerated by engagement of the adaptive immune system. Atherosclerosis triggers the breakdown of tolerance to self-components. This loss of tolerance is reflected in defective expression of immune checkpoint molecules, dysfunctional antigen presentation, and aberrations in T cell populations - most notably in regulatory T (Treg) cells - and in the production of autoantibodies. The breakdown of tolerance to self-proteins that is observed in ASCVD may be linked to the conversion of Treg cells to 'exTreg' cells because many Treg cells in ASCVD express T cell receptors that are specific for self-epitopes. Alternatively, or in addition, breakdown of tolerance may trigger the activation of naive T cells, resulting in the clonal expansion of T cell populations with pro-inflammatory and cytotoxic effector phenotypes. In this Perspective, we review the evidence that atherosclerosis is associated with a breakdown of tolerance to self-antigens, discuss possible immunological mechanisms and identify knowledge gaps to map out future research. Rational approaches aimed at re-establishing immune tolerance may become game changers in treating ASCVD and in preventing its downstream sequelae, which include heart attacks and strokes.

Kupffer cells dictate hepatic responses to the atherogenic dyslipidemic insult

Apolipoprotein-B (APOB)-containing lipoproteins cause atherosclerosis. Whether the vasculature is the initially responding site or if atherogenic dyslipidemia affects other organs simultaneously is unknown. Here we show that the liver responds to a dyslipidemic insult based on inducible models of familial hypercholesterolemia and APOB tracing. An acute transition to atherogenic APOB lipoprotein levels resulted in uptake by Kupffer cells and rapid accumulation of triglycerides and cholesterol in the liver. Bulk and single-cell RNA sequencing revealed a Kupffer-cell-specific transcriptional program that was not activated by a high-fat diet alone or detected in standard liver function or pathological assays, even in the presence of fulminant atherosclerosis. Depletion of Kupffer cells altered the dynamic of plasma and liver lipid concentrations, indicating that these liver macrophages help restrain and buffer atherogenic lipoproteins while simultaneously secreting atherosclerosis-modulating factors into plasma. Our results place Kupffer cells as key sentinels in organizing systemic responses to lipoproteins at the initiation of atherosclerosis.

Development of a CCR2 targeted 18F-labeled radiotracer for atherosclerosis imaging with PET

Atherosclerosis is a chronic inflammatory disease and the leading cause of morbidity and mortality worldwide. CC motif chemokine ligand 2 and its corresponding cognate receptor 2 (CCL2/CCR2) signaling has been implicated in regulating monocyte recruitment and macrophage polarization during inflammatory responses that plays a pivotal role in atherosclerosis initiation and progression. In this study, we report the design and synthesis of a novel 18F radiolabeled small molecule radiotracer for CCR2-targeted positron emission tomography (PET) imaging in atherosclerosis. The binding affinity of this radiotracer to CCR2 was evaluated via in vitro binding assay using CCR2+ membrane and cells. Ex vivo biodistribution was carried out in wild type mice to assess radiotracer pharmacokinetics. CCR2 targeted PET imaging of plaques was performed in two murine atherosclerotic models. The sensitive detection of atherosclerotic lesions highlighted the potential of this radiotracer for CCR2 targeted PET and warranted further optimization.

EIF2α-mediated integrated stress response links multiple intracellular signaling pathways to reprogram vascular smooth muscle cell fate in carotid artery plaque

BackgroundCarotid arterial atherosclerotic stenosis is a well-recognized pathological basis of ischemic stroke; however, its underlying molecular mechanisms remain unknown. Vascular smooth muscle cells (VSMCs) play fundamental roles in the initiation and progression of atherosclerosis. Organelle dynamics have been reported to affect atherosclerosis development. However, the association between organelle dynamics and various cellular stresses in atherosclerotic progression remain ambiguous. MethodsIn this study, we conducted transcriptomics and bioinformatics analyses of stable and vulnerable carotid plaques. Primary VSMCs were isolated from carotid plaques and subjected to histopathological staining to determine their expression profiles. Endoplasmic reticulum (ER), mitochondria, and lysosome dynamics were observed in primary VSMCs and VSMC cell lines using live-cell imaging. Moreover, the mechanisms underlying disordered organelle dynamics were investigated using comprehensive biological approaches. ResultsER whorls, a representative structural change under ER stress, are prominent dynamic reconstructions of VSMCs between vulnerable and stable plaques, followed by fragmented mitochondria and enlarged lysosomes, suggesting mitochondrial stress and lysosomal defects, respectively. Induction of mitochondrial stress alleviated ER stress and autophagy in an eukaryotic translation initiation factor (eIF)-2α-dependent manner. Furthermore, the effects of eIF2α on ER stress, mitochondrial stress, and lysosomal defects were validated using clinical samples. ConclusionOur results indicate that morphological and functional changes in VSMC organelles, especially in ER whorls, can be used as reliable biomarkers for atherosclerotic progression. Moreover, eIF2α plays an important role in integrating multiple stress-signaling pathways to determine the behavior and fate of VSMCs.

Carbon Nanodots Inhibit Tumor Necrosis Factor-α-Induced Endothelial Inflammation through Scavenging Hydrogen Peroxide and Upregulating Antioxidant Gene Expression in EA.hy926 Endothelial Cells.

Carbon nanodots (CNDs) are a new type of nanomaterial with a size of less than 10 nanometers and excellent biocompatibility, widely used in fields such as biological imaging, transmission, diagnosis, and drug delivery. However, its potential and mechanism to mediate endothelial inflammation have yet to be explored. Here, we report that the uptake of CNDs by EA.hy926 endothelial cells is both time and dose dependent. The concentration of CNDs used in this experiment was found to not affect cell viability. TNF-α is a known biomarker of vascular inflammation. Cells treated with CNDs for 24 h significantly inhibited TNF-α (0.5 ng/mL)-induced expression of intracellular adhesion molecule 1 (ICAM-1) and interleukin 8 (IL-8). ICAM-1 and IL-8 are two key molecules responsible for the activation and the firm adhesion of monocytes to activated endothelial cells for the initiation of atherosclerosis. ROS, such as hydrogen peroxide, play an important role in TNF-α-induced inflammation. Interestingly, we found that CNDs effectively scavenged H2O2 in a dose-dependent manner. CNDs treatment also increased the activity of the antioxidant enzyme NQO1 in EA.hy926 endothelial cells indicating the antioxidant properties of CNDs. These results suggest that the anti-inflammatory effects of CNDs may be due to the direct H2O2 scavenging properties of CNDs and the indirect upregulation of antioxidant enzyme NQO1 activity in endothelial cells. In conclusion, CND can inhibit TNF-α-induced endothelial inflammation, possibly due to its direct scavenging of H2O2 and the indirect upregulation of antioxidant enzyme NQO1 activity in endothelial cells.

TGF-β Isoforms and GDF-15 in the Development and Progression of Atherosclerosis.

The effect of oxidised lipoproteins on the endothelium, monocytes, platelets, and macrophages is a key factor in the initiation and development of atherosclerosis. Antioxidant action, lipoprotein metabolism, and chronic inflammation are the fields of research interest for better understanding the development of the disease. All the fields are related to inflammation and hence to the secretion of cytokines, which are being investigated as potential diagnostic markers for the onset of atherosclerosis. Pathways of vascular damage are crucial for the development of new laboratory readouts. The very early detection of endothelial cell damage associated with the onset of atherosclerosis, allowing the initiation of therapy, remains a major research goal. This article summarises the latest results on the relationship of tumour growth factor beta (TGF-β) isoforms and growth differentiation factor 15 (GDF-15) to the pathogenesis of atherosclerosis: which cells involved in atherosclerosis produce them, which effectors stimulate their synthesis and secretion, how they influence atherosclerosis development, and the relationship between the levels of TGF-β and GDF-15 in the blood and the development and extent of atherosclerosis.

Dietary antioxidant intake increases ankle brachial pressure index in men but not in women: a cross-sectional study.

Atherosclerosis is a significant cause of cardiovascular and cerebrovascular diseases, with a greater impact on men than women. Dietary antioxidant intake is inversely related to the risk of atherosclerosis development. We aimed to investigate the association between dietary composite antioxidant intake and the ankle brachial pressure index (ABPI). The ABPI is not only used for assessing the progression of arterial lesions but also for stratifying the risk of atherosclerotic disease. We conducted a cross-sectional analysis involving 1,049 participants from the National Health and Nutrition Examination Survey (NHANES). We examined six antioxidants (zinc, selenium, carotenoids, and vitamins A, C, and E) and a composite dietary antioxidant index (CDAI) derived from these antioxidants as exposure variables. The primary outcomes encompassed cardio-metabolic parameters, including body mass index (BMI), body fat mass (BFM), systolic and diastolic blood pressure, triglycerides, HDL and LDL cholesterol, C-reactive protein, and the Ankle-Brachial Pressure Index (ABPI). Associations and interactions between variables were assessed using linear regression analyses. Moreover, mediation and moderation analysis is employed. Hierarchical multiple regression analysis revealed that among men, dietary intake of zinc, selenium, and vitamin A remained positively associated with a higher ABPI even after adjusting for covariates. Conversely, in the stratified regression analysis based on CDAI quartiles, a U-shaped association between CDAI and ABPI was suggested. Notably, no significant association between dietary antioxidant intake and ABPI was observed among women. CDAI, intake of Vitamin A, Vitamin C, and Vitamin E do not influence all-cause death through mediation by abpi, but rather have a direct effect on all-cause death. Moreover, there is a significant interaction between the intake of Vitamin A and gender, where a daily intake of Vitamin A more than 776 ug is especially beneficial for women. The combined intake of nutrients with antioxidant properties may prevent the initiation and progression of atherosclerosis and influence the outcome in a sex-specific manner.

The influence of inlet flow asymmetry on the carotid bifurcation hemodynamics

Arterial bifurcations are known to be high-risk areas for the initiation of atherosclerosis. The appearance and growth of atherosclerotic plaques in the bifurcation of the carotid artery can result in severe consequences such as cerebrovascular accidents. The common signs of an atherogenic risk center around the surpassing critical values by certain hemodynamic indices, which are distributed over the artery wall. These indices are related to the effect of blood flow on the arterial wall, and their distribution is influenced by both the bifurcation’s geometric shape and the flow structure at its inlet. The objective of this study is to carry out a comparative analysis of hemodynamic indices in personal-specific models of carotid bifurcation with centrally symmetric and asymmetric input flows. The examined geometric models of bifurcation are based on computed angiography data obtained from the individuals free of apparent pathology. By using computational fluid dynamics within these models, the distribution of hemodynamic indices in a steady periodic flow is calculated and critical zones are determined for them. All the models are divided into two groups – those with symmetric and those with asymmetric input flows. For each model with asymmetric input flow, an alternative geometry is designed to ensure inlet flow symmetry, and comparative numerical calculations of the blood flow are carried out. The results of comparative analysis reveal that the distribution of hemodynamic indices is simpler for the group with symmetric input flow. A comparison of the averages between these two groups with symmetrical and natural asymmetric input flows indicates a 55% better result for the latter group. Furthermore, for almost all models with asymmetric input flow, their alternative models give worse hemodynamic results. Thus, hemodynamic indices in simpler models with symmetrical input flow can serve as an upper estimate for indices in models with natural asymmetric flow. A total of 89 models are included in the study.