Plaque Development Research Articles

Evolving Concepts of the SCORE System: Subtracting Cholesterol from Risk Estimation: A Way for a Healthy Longevity?

The role of cholesterol, mainly low-density lipoproteins (LDL-C), as a causal risk factor for atherosclerotic cardiovascular disease (ASCVD) is now established and accepted by the international scientific community. Based on this evidence, the European and American guidelines recommend early risk stratification and "rapid" achievement of the suggested target according to the risk estimation to reduce the number of major cardiovascular events. Prolonged exposure over the years to high levels of LDL-C is one of the determining factors in the development and progression of atherosclerotic plaque, on which the action of conventional risk factors (cigarette smoking, excess weight, sedentary lifestyle, arterial hypertension, diabetes mellitus) as well as non-conventional risk factors (gut microbiota, hyperuricemia, inflammation), alone or in combination, favors the destabilization of the atherosclerotic lesion with rupture/fissuration/ulceration and consequent formation of intravascular thrombosis, which leads to the acute clinical manifestations of acute coronary syndromes. In the current clinical practice, there is a growing number of cases that, although extremely common, are emblematic of the concept of long-term exposure to the risk factor (LDL hypercholesterolemia), which, not adequately controlled and in combination with other risk factors, has favored the onset of major cardiovascular events. The triple concept of "go lower, start earlier and keep longer!" should be applied in current clinical practice at any level of prevention. In the present manuscript, we will review the current evidence and documents supporting the causal role of LDL-C in determining ASCVD and whether it is time to remove it from any score.

Coronary CTA-based vascular radiomics predicts atherosclerosis development proximal to LAD myocardial bridging.

Cardiac cycle morphological changes can accelerate plaque growth proximal to myocardial bridging (MB) in the left anterior descending artery (LAD). To assess coronary computed tomography angiography (CCTA)-based vascular radiomics for predicting proximal plaque development in LAD MB. Patients with repeated CCTA scans showing LAD MB without proximal plaque in index CCTA were included from Jinling Hospital as a development set. They were divided into training and internal testing in an 8:2 ratio. Patients from four other tertiary hospitals were set as external validation set. The endpoint was proximal plaque development of LAD MB in follow-up CCTA. Four vascular radiomics models were built: MB centreline (MB CL), proximal MB CL (pMB CL), MB cross-section (MB CS), and proximal MB CS (pMB CS), whose performances were evaluated using area under the receiver operating characteristic curve (AUC), integrated discrimination improvement (IDI), and net reclassification improvement (NRI). In total, 295 patients were included in the development (n = 192; median age, 54 ± 11 years; 137 men) and external validation sets (n = 103; median age, 57 ± 9 years; 57 men). The pMB CS vascular radiomics model exhibited higher AUCs in training, internal test, and external sets (AUC = 0.78, 0.75, 0.75) than the clinical and anatomical model (all P < 0.05). Integration of the pMB CS vascular radiomics model significantly raised the AUC of the clinical and anatomical model from 0.56 to 0.75 (P = 0.002), along with enhanced NRI [0.76 (0.37-1.14), P < 0.001] and IDI [0.17 (0.07-0.26), P < 0.001] in the external validation set. The CCTA-based pMB CS vascular radiomics model can predict plaque development in LAD MB.

Hyperlipidemia-induced hematopoiesis is repressed by MLKL in endothelial cells of the splenic niche.

Dysregulation of the hematopoietic niche during hyperlipidemia facilitates pathologic leukocyte production, driving atherogenesis. Although definitive hematopoiesis occurs primarily in the bone marrow, during atherosclerosis this also occurs in the spleen. Cells of the bone marrow niche, particularly endothelial cells, have been studied in atherosclerosis, although little is known about how splenic endothelial cells respond to the atherogenic environment. Here we show unique dysregulated pathways in splenic compared to bone marrow endothelial cells during atherosclerosis, including perturbations of lipid metabolism and endocytic trafficking pathways. As part of this response, we identify the mixed lineage kinase domain-like (MLKL) protein as a repressor of splenic, but not bone marrow, myelopoiesis. Silencing MLKL in splenic endothelial cells results in inefficient endosomal trafficking and lipid accumulation, ultimately promoting the production of myeloid cells that participate in plaque development. These studies identify endocytic trafficking by MLKL as a key mechanism of splenic endothelial cell maintenance, splenic hematopoiesis and, subsequently, atherosclerosis.

Mechanical Assessment in Atherosclerosis Based on Photoacoustic Viscoelasticity Imaging

Early identification of vulnerable plaques is a major challenge in diagnosis and assessment of atherosclerosis. In atherosclerotic plaque development, the proportion change in components caused plaque mechanical property change and induced plaque rupture. In this paper, a photoacoustic viscoelasticity imaging (PAVEI) technique was proposed to measure the viscosity–elasticity ratio of atherosclerotic plaque and evaluated for the potential in characterizing vulnerable plaques. Apolipoprotein E-knockout mice fed with a high-fat/high-cholesterol diet were chosen as the atherosclerotic model. Plaque component phantoms were examined to demonstrate the high efficiency of PAVEI in detecting the proportion change in components compared to single elasticity or viscosity detection. Finally, atherosclerotic plaques from mice aortas at different stages were imaged by PAVEI, which provided an insight into the compositional and functional characterization of vulnerability plaques and suggested its potential applications in the identification of high-risk plaques.

The Impact of Metabolic and Bariatric Surgery on Apo B100 Levels in Individuals with high BMI: A Multi-Centric Prospective Cohort Study.

Metabolic and Bariatric surgery (MBS) leads to significant weight loss and improvements in obesity-related comorbidities. However, the impact of MBS on Apolipoprotein B100 (Apo-B100) regulation is unclear. Apo-B100 is essential for the assembly and secretion of serum lipoprotein particles. Elevated levels of these factors can accelerate the development of atherosclerotic plaques in blood vessels. This study aimed to evaluate changes in Apo-B100 levels following MBS. 121 participants from the Iranian National Obesity and Metabolic Surgery Database (INOSD) underwent Laparoscopic Sleeve Gastrectomy (LSG) (n = 43), One-Anastomosis Gastric Bypass (OAGB) (n = 70) or Roux-en-Y Gastric Bypass (RYGB) (n = 8). Serum Apo-B100, lipid profiles, liver enzymes, and fasting glucose were measured preoperatively and six months postoperatively. Apo-B100 levels significantly decreased from 94.63 ± 14.35 mg/dL preoperatively to 62.97 ± 19.97 mg/dL after six months (p < 0.01), alongside reductions in total cholesterol, triglycerides, LDL, VLDL, AST, and ALT (p < 0.05). Greater Apo-B100 reductions occurred in non-diabetics versus people with diabetes (p = 0.012) and strongly correlated with baseline Apo-B100 (r = 0.455, p < 0.01) and LDL levels (r = 0.413, p < 0.01). However, surgery type did not impact Apo-B100 changes in multivariate analysis (p > 0.05). Bariatric surgery leads to a significant reduction in Apo-B100 levels and improvements in lipid profiles and liver enzymes, indicating a positive impact on dyslipidemia and cardiovascular risk in individuals with high BMI.

Impact of Probiotic Lactiplantibacillus plantarum ATCC 14917 on atherosclerotic plaque and its mechanism.

Atherosclerosis is viewed as not just as a problem of lipid build-up in blood vessels, but also as a chronic inflammatory disease involving both innate and acquired immunity. In atherosclerosis, the inflammation of the arterial walls is the key characteristic that significantly contributes to both the instability of plaque and the occlusion of arteries by blood clots. These events ultimately lead to stroke and acute coronary syndrome. Probiotics are living microorganisms that, when consumed in the right quantities, offer advantages for one's health. The primary objective of this study was to investigate the influence of Lactiplantibacillus plantarum ATCC 14917 (ATCC 14917) on the development of atherosclerotic plaques and its underlying mechanism in Apo lipoprotein E-knockout (Apoe-/-mice). In this study, Apoe-/-mice at approximately 8weeks of age were randomly assigned to three groups: a Normal group that received a normal chow diet, a high fat diet group that received a gavage of PBS, and a Lactiplantibacillus plantarum ATCC 14917 group that received a high fat diet and a gavage of 0.2ml ATCC 14917 (2 × 109CFU/mL) per day for a duration of 12weeks. Our strain effectively reduced the size of plaques in Apoe-/-mice by regulating the expression of inflammatory markers, immune cell markers, chemokines/chemokine receptors, and tight junction proteins (TJPs). Specifically, it decreased the levels of inflammatory markers (ICAM-1, CD-60 MCP-1, F4/80, ICAM-1, and VCAM-1) in the thoracic aorta, (Ccr7, cd11c, cd4, cd80, IL-1β, TNF-α) in the colon, and increased the activity of ROS-scavenging enzymes (SOD-1 and SOD-2). It also influenced the expression of TJPs (occludin, ZO-1, claudin-3, and MUC-3). In addition, the treatment of ATCC 14917 significantly reduced the level of lipopolysaccharide in the mesenteric adipose tissue. The findings of our study demonstrated that our strain effectively decreased the size of atherosclerotic plaques by modulating inflammation, oxidative stress, intestinal integrity, and intestinal immunity.

Exploring Atherosclerosis, Oxidized LDL, Insulin, and Tailored Diet Strategies in Cardiac Patient Assessment

Background Plaque development in vessels which supply blood to heart muscles is caused by atherosclerosis, a slow but progressive process that leads to coronary artery disease (CAD). Arteries become gradually blocked by oxidized fatty acids, with excess fat intake or abnormalities in fat metabolism causing body changes. These changes may lead to an increase in LDL cholesterol, triglycerides, as well as a reduction in HDL cholesterol. The oxidation of excess low density protein (LDL) is a complex process involving many factors, with insulin and obesity playing a significant role and associated with many metabolic syndromes. The current study aims to determine the concentration of oxidized LDL in patients who suffer with cardio vascular diseases (CVDs) and to understand the correlation between oxidation and insulin resistance in cardiac forbearing. Method The method used was to collect data from 30 patients admitted in the cardiology ward. For this purpose, an assessment proforma was built, which included anthropometric measurements, physical activity level, dietary history, and blood tests for lab findings such as lipid profiles. Results The key findings determined that the anomalous function of AKT protein, which is present in pancreatic β cells, as well as disruption in PKC pathway cause phosphorylation in alpha and beta cells of pancreas, which causes diabetes and leads to heart attack. Conclusion The aberrant changes in sugar test and lipid profile including Hb1Ac (9%), fasting blood glucose (250mg/dl), total cholesterol (342mg/dl), LDL (less than 250mg/dl), HDL (49 F mg/dl), and total triglycerides (215mg/dl) causes serious discomfort for patients.

GPX4 overexpression does not alter atherosclerotic plaque development in ApoE knock-out mice.

Ferroptosis is a type of regulated necrosis that is associated with iron-dependent accumulation of lipid hydroperoxides. Given that iron deposition and lipid peroxidation initiate ferroptosis in atherosclerosis and contribute to further plaque development, we hypothesized that inhibition of ferroptosis could be of value in the treatment of atherosclerosis. Glutathione peroxidase 4 (GPX4) is the only enzyme known capable of reducing lipid hydroperoxides. Previous studies have demonstrated that inactivation of GPX4 results in ferroptosis, while overexpression of GPX4 confers resistance to ferroptosis. In the present study, we examined the impact of GPX4 overexpression on the development of atherosclerotic plaques. GPX4-overexpressing mice (GPX4Tg/+) were crossbred with ApoE-/- mice and fed a western-type diet for 16 weeks. Atherosclerotic plaques of GPX4Tg/+ ApoE-/- mice showed increased GPX4 expression and a reduced amount of lipid hydroperoxides. However, plaque size and composition were not different as compared to control animals. Similarly, GPX4-overexpressing vascular smooth muscle cells and bone marrow-derived macrophages were not protected against lipid peroxidation and cell death triggered by the ferroptosis inducers erastin and 1S,3R-RSL3. We concluded that GPX4 overexpression reduces lipid peroxidation in plaques of ApoE-/- mice, yet GPX4 overexpression is not sufficiently powerful to change plaque size or composition.

When mycosis fungoides seems not to be within the spectrum of clinical and histopathological differential diagnoses.

The most prevalent primary cutaneous T-cell lymphoma, mycosis fungoides (MF), is characterized by the development of plaques and nodules after an erythematous patchy phase that is non-specific. An infiltrate of atypical small- to medium-sized cerebriform lymphocytes in the superficial dermis, with variable epidermotropism, is the histopathological hallmark of the disease. In more advanced stages of the illness, large-cell transformation may be seen. Early diagnosis of MF can be very challenging based only on histopathologic or clinical findings, so it is critical to have a clinical-pathological correlation. Many atypical variants of MF that deviate from the classic Alibert-Bazin presentation of the disease have been described over the past 30 years, sometimes with different prognostic and therapeutic implications. Clinically or histopathologically, they can mimic a wide range of benign inflammatory skin disorders. To make a conclusive diagnosis in these cases, it is recommended to take multiple biopsies from various lesions and to carefully correlate the clinical and pathological findings. We have outlined the various facets of the illness in this review, positioning MF as a "great imitator", with an emphasis on the more recently identified variations, differential diagnosis, and its benign mimics.

HDL and plaque regression in a multiphase model of early atherosclerosis

Atherosclerosis is a chronic disease of the arteries characterised by the accumulation of lipids and lipid-engorged cells in the artery wall. Early plaque growth is aggravated by the deposition of low density lipoproteins (LDL) in the wall and the subsequent immune response. High density lipoproteins (HDL) counterbalance the effects of LDL by accepting cholesterol from macrophages and removing it from the plaque. In this paper, we develop a free boundary multiphase model to investigate the effects of LDL and HDL on early plaque development. We examine how the rates of LDL and HDL deposition affect cholesterol accumulation in macrophages, and how this impacts cell death rates and emigration. We identify a region of LDL–HDL parameter space where plaque growth stabilises for low LDL and high HDL influxes, due to macrophage emigration and HDL clearance that counterbalances the influx of new cells and cholesterol. We explore how the efferocytic uptake of dead cells and the recruitment of new macrophages affect plaque development for a range of LDL and HDL influxes. Finally, we consider how changes in the LDL–HDL profile can change the course of plaque development. We show that changes towards lower LDL and higher HDL can slow plaque growth and even induce regression. We find that these changes have less effect on larger, more established plaques, and that temporary changes will only slow plaque growth in the short term.

Abstract 2003: Epigenetic And Phenotypic Modulation Of Adventitial Fibroblasts In Atherosclerosis By Coronary Artery Risk Gene Tcf21

The vascular adventitia has long been postulated to play a key role in atherosclerosis, but the relevant adventitial cell populations and the mechanisms by which they influence atherosclerosis have remained elusive. To characterize relevant adventitial cells and their regulators, we have combined single cell multi-omic murine and human data with human genetics. Single cell transcriptomic and epigenetic analysis of both murine and human arterial tissue revealed a unique population of adventitial fibroblasts (AdvFib). Transcriptome and epigenome analysis revealed disproportionate enrichment for coronary artery disease (CAD) GWAS risk loci and genes in AdvFib, suggesting that AdvFib actively contributes to disease. Leveraging this rich information, we created a novel AdvFib specific CreERT2 murine model to enable AdvFib specific genetic manipulation. Murine lineage tracing using this novel AdvFib-specific model of atherosclerosis revealed early expansion and transcriptomic alteration of AdvFib during plaque development, akin to phenotypic modulation of SMC. Cell-cell communication analysis demonstrated an increase in AdvFib-driven crosstalk with other cell types during early phases of atherosclerosis, including activation of pro-inflammatory (Il6, Ccl2/7, Cxcl12) genes. Computational enrichment analysis of regulatory region of genes associated with AdvFib modulation points to a prominent role for TCF21 , a CAD GWAS risk gene. Single cell time course data of atherosclerosis demonstrates that Tcf21 is expressed primarily in AdvFib with dynamic alteration of its expression during atherosclerosis. AdvFib-specific Tcf21 loss in murine model of atherosclerosis resulted in altered expression of ECM and inflammatory genes, with corresponding changes in recruitment of inflammatory cells. Mechanistically, through histone modification cut-and-tag in human coronary AdvFib, we showed that TCF21 regulates AdvFib activation through epigenetic reprograming of key cytokine and cell fate regulators by binding and altering H3K27Acetylation. Collectively, our results begin to establish the role of AdvFib in atherosclerosis and highlight the importance of TCF21 in this process through a precise epigenetic mechanism.

Abstract 2010: Atherosclerotic Plaque Macrophages Drive Abdominal Aortic Aneurysm Formation

Introduction: Cigarette smoking (CS) contributes to the most deaths in abdominal aortic aneurysms (AAA) and tobacco use associates with early damage to the abdominal aorta. Associated risk factors, such as hyperlipidemia, link clinical AAA to the atherosclerotic process, suggesting common pathogenetic features with plaque development. We hypothesized that CS exposure exacerbates atherosclerotic disease in the abdominal aorta by increasing the recruitment of inflammatory macrophages that mediate arterial degradation and AAA formation. Methods: Adult male Apoe deficient mice commenced a high cholesterol diet and were concomitantly exposed to CS or room air (RA) for 4, 8, 12, and 16 weeks. As plaque macrophages are highly prevalent in advanced AAA, additional CS exposed mice received a selective CSF1R inhibitor, PLX3397, for up to 16 weeks to deplete macrophages. AAA incidence, atherosclerotic plaque burden and lesion composition were assessed in the aorta by immunofluorescence, Movat, EVG, and Oil Red O staining. Results: CS induced AAA at all timepoints with the highest incidence of 37% at 16 weeks of exposure (n=151 CS, n=75 RA p&lt; 0.05). Aneurysms always coincided with atherosclerosis (n=7 CS, n=7 CS/AAA p&lt;0.05), and severe elastin fragmentation was consistently overlaid by plaque (n=20 CS p&lt;0.05, Fig 1A and B). In some cases, lesions also associated with aortic rupture, causing death in ~11% of animals (n = 35 RA, n = 46 CS p&lt;0.04). CD68+ macrophages associated highly with severe elastin damage but less at intact regions (2.6-fold p&lt;0.0001, Fig 1C). PLX3397-mediated macrophage depletion attenuated plaque development and prevented AAA (n=20 treated, n=27 control p&lt;0.05, Fig 1D). Conclusion: CS exacerbates atherosclerosis and increases the accumulation of macrophages at sites of arterial injury. Depletion of macrophages results in a lack of aneurysm formation, highlighting their capacity to directly injure the aortic wall and necessity to mediate AAA.

Abstract 134: Lesion-specific Suppression Of YAP/TAZ By Biomimetic Nanoparticles Ameliorates Atherosclerosis

Introduction: Recent evidence highlights the potential therapeutic benefit of targeting YAP/TAZ in mitigating atherosclerosis. However, challenges associated with systemic delivery hinder the translation of the mechanistic discovery into an effective treatment. This study aimed to address the challenges by developing a lesion-specific nanodrug to achieve site-specific inhibition of YAP/TAZ for atherosclerosis therapy. Hypothesis: We have formulated a novel monocyte membrane-coated nanoparticle (MoNP) platform designed to facilitate precise delivery of payloads to atherosclerotic arteries. Our hypothesis is that leveraging MoNP for the targeted delivery of verteporfin (VP), a potent YAP/TAZ inhibitor, will significantly enhance the efficacy in mitigating atherosclerosis. Methods: Polymeric nanoparticles containing VP were prepared using an emulsion approach, followed by enclosing them with plasma membranes isolated from monocytes, yielding MoNP-VP. The pharmacological effects of MoNP-VP were assessed on cultured vascular and immune cells, as well as in the atherosclerotic mouse model. Results: Our in vivo findings demonstrated that the administration of MoNP-VP, as opposed to free VP, led to a substantial reduction in arterial inflammation and plaque development, suggesting that VP delivered by MoNP is a more effective route than its free drug counterpart. To dissect the mechanisms of actions, we analyzed the arterial tissues post-treatment using scRNA-seq analysis. Our results identified 9 distinct cell clusters within the affected arteries. Specifically, MoNP-VP treatment led to a decrease in macrophage (MΦ) clusters and an increase in the cluster of smooth muscle cells (SMC). Furthermore, our in vitro assays confirmed the efficacies of MoNP-VP in reducing the atheroprone phenotypes. These include diminished endothelial cell activation, less proliferation and migration of SMC, and a reduction in foam cell formation from MΦ. Conclusion: Together, these findings support the notion that targeting YAP/TAZ dysregulation is a feasible strategy for reducing plaque development and progression and demonstrate that MoNP-VP is a highly effective nanodrug for treating atherosclerosis.

A potential early-atheroprotective target: Irgm1 mediates lymphangiogenesis through LEC autophagy by Tfeb translocation

Lymphatic dysfunction is a pivotal pathological mechanism underlying the development of early atherosclerotic plaques. Potential targets of lymphatic function must be identified to realize the early prevention and treatment of atherosclerosis (AS). The immunity-related GTPase Irgm1 is involved in orchestrating cellular autophagy and apoptosis. However, the effect of Irgm1 on early AS progression, particularly through alterations in lymphatic function, remains unclear. In this study, we confirmed the protective effect of lymphangiogenesis on early-AS in vivo. Subsequently, an in vivo model of early AS mice with Irgm1 knockdown shows that Irgm1 reduces early atherosclerotic plaque burden by promoting lymphangiogenesis. Given that lymphatic endothelial cell (LEC) autophagy significantly contributes to lymphangiogenesis, Irgm1 may enhance lymphatic circulation by promoting LEC autophagy. Moreover, Irgm1 orchestrates autophagy in LECs by inhibiting mTOR and facilitating nuclear translocation of Tfeb. Collectively, these processes lead to lymphangiogenesis. Thus, this study establishes a link between Irgm1 and early AS, thus revealing a novel mechanism by which Irgm1 exerts an early protective influence on AS within the context of lymphatic circulation. The insights gained from this study have the potential to revolutionize the approach and management of AS onset.

Abstract 3131: An Investigation Into The Interplay Between Epha2 And Inflammatory Responses In Vascular Smooth Muscle Cells

Cardiovascular disease continues to be a leading cause of death in the United States. A major underlying cause of cardiovascular events such as stroke and myocardial infarction is atherosclerosis. Notable mediators in the pathogenesis of atherosclerosis include vascular smooth muscle cells (VSMCs) and inflammation. During atherogenesis, the SMCs undergo phenotypic change from a quiescent state to a synthetic, proliferative state. The synthetic SMCs drive neointima formation which influences the stenosis characteristic of atherosclerosis. Signaling of a receptor tyrosine kinase called EphA2 has been previously determined to have a role in SMC phenotypic change. It was found that a global and SMC specific knockdown (KD) of EphA2 resulted in decreased plaque formation, suggesting the role of EphA2 expression in promoting SMC proliferation. Inflammation is another important factor that contributes to plaque formation. Oxidized low-density lipoproteins (LDLs) have been found to also cause VSMCs to undergo change to a synthetic phenotype, one that resembles macrophages. Cytokines released by macrophages orchestrate the pro-inflammatory response that affects the development and stability of atherosclerotic plaques. Considering the important role inflammation also serves in the progression of plaque formation, we investigated the relationship between EphA2 and VSMC-mediated inflammatory response. Cre-flox breeding was performed to achieve EphA2 knockout (KO) specifically in VSMCs of 8-10-wk old ApoE -/- mice. Successful KO was confirmed with PCR and Western blot. Si-RNA was transfected to achieve KD in human SMCs. The cells were then treated with cytokines, including IL-1 beta, TNF-alpha, IL-6, IL-33, and interferon-gamma, followed by RT-qPCR analysis to measure expression of inflammatory genes. To assess cytokine secretion, we utilized a cytokine array to measure presence of the cytokines of interest. Protein analysis to quantify expression of inflammatory proteins in KO vs control cells was done via Western blot. We observed that the loss of EphA2 causes significant reductions in the production of several proinflammatory cytokines and chemokines, indicating its role in mediating VSMC inflammatory responses.

Abstract 2069: Impact Of Endothelial Stiffening And CD36-mediated Lipid Uptake On Atherosclerotic Lesion Formation

Objective: To determine the impact of endothelial stiffening induced by CD36 (cluster of differentiation 36) lipid uptake in the development of atherosclerosis. Approach and Results: Endothelial stiffening of intact en face monolayers, as assessed by atomic force microscopy, reveal the hyperlipidemic mouse model of atherosclerosis, LDLR -/- (low density lipoprotein receptor knockout) is significantly stiffer, especially in the atheroprone aortic arch, as compared to wild type controls (n=4 male mice with 8-15 tissue measurement sites per condition per mouse, p&lt;0.05). Furthermore, a 4-5 month high fat diet (HFD) feeding in LDLR -/- mice resulted in significantly enhanced stiffening compared to regular chow feeding, an effect that was observed in males but not females (n=6-8 mice, p&lt;0.05). There was a significantly greater plaque development, as analyzed using Oil O Red staining for lipids, in male HFD-fed LDLR -/- mice, as compared to age-matched females (n=5-6, p&lt;0.05). No significant difference between males and females was found in lipid panel parameters (n=4-6) or weight gain (n=10-14). Specific downregulation of CD36 in male hypercholesterolemic Cdh5.CreERT2CD36fl/fl LDLR -/- mice led to both a significant decrease in endothelial stiffening (n=5 mice, p&lt;0.05) and in the areas of atherosclerotic lesion formation (n=5-6 mice, p&lt;0.05). Mechanistically, we show that the saturated fatty acid, palmitic acid, increased endothelial stiffening in the en face monolayers of wild type mice, an effect which is prevented by the pre-treatment of the CD36 irreversible inhibitor, SSO (sulfo-N-succinimidyl oleate, n=5-6 male mice, p&lt;0.05). Conclusions: These results highlight that endothelial stiffness from intact aortas and atherosclerotic plaque formation following HFD feeding is strongly dependent on endothelial CD36.

Abstract 2070: Myeloid Smyd2 Deficiency Exacerbates Atherosclerosis Via Promoting Plaque Necrosis And Calcification

Introduction: The accumulation of lipoprotein-laden macrophages within arterial walls marks the earliest phase of atherosclerotic cardiovascular disease, giving rise to foam cells. Here, we aim to define the previously unexplored role of myeloid specific SMYD2 (a histone lysine methyltransferase) in atherosclerosis and plaque formation. Methods: Myeloid-specific Smyd2 knockout mice in ApoE -/- background (Smyd2 mKO ApoE -/- ) and their littermate controls (Smyd2 fl/fl ApoE -/- ) were subjected to Western diet (WD) feeding for up to 26 weeks. Atherosclerotic plaque distribution was examined by en-face Oil Red O (ORO) staining of freshly collected aortas. Hematoxylin &amp; Eosin (H&amp;E) staining on brachiocephalic artery (BCA) tissues were performed to determine total plaque size, lipid pool area, and necrotic core area. Plaque calcification was determined by von Kossa staining and Alizarin Red S staining. Primary bone marrow derived macrophages (BMDMs) isolated from Smyd2 fl/fl ApoE -/- and Smyd2 mKO ApoE -/- mice and cultured RAW 246.7 cells (with Smyd2 knock-down) were used for in vitro studies including calcification assay, PR-PCR, and Western blot analysis. Results: Myeloid Smyd2 deficient mice demonstrated significantly increased aortic plaque burden on ORO staining as compared to control mice following WD feeding, though with slower WD-induced body weight gain relative to Smyd2 fl/fl ApoE -/- control mice. H&amp;E staining of BCA indicated that there was significant reduction in total lumen and lipid core area, while significantly increased total plaque and necrotic core in Smyd2 mKO ApoE -/- mice. Myeloid Smyd2 deletion promotes plaque calcification in mice fed with WD, and in cultured BMDMs and RAW 246.7 cells treated with calcification promoting media. Gene expression analysis of key calcification factors of aortic tissues and cultured cells showed significant upregulation of Sox9 and Msx2 genes in aortas of WD-fed Smyd2 mKO ApoE -/- mice and cultured Smyd2 deficient cells, as compared to controls. Conclusion: We delineated the consequences of Smyd2 deficiency in macrophages on atherosclerotic plaque development, particularly its impact on plaque necrosis and calcification.

Exacerbated atherosclerosis in progeria is prevented by progerin elimination in vascular smooth muscle cells but not endothelial cells.

Hutchinson-Gilford progeria syndrome (HGPS) is a rare disease caused by the expression of progerin, a mutant protein that accelerates aging and precipitates death. Given that atherosclerosis complications are the main cause of death in progeria, here, we investigated whether progerin-induced atherosclerosis is prevented in HGPSrev-Cdh5-CreERT2 and HGPSrev-SM22α-Cre mice with progerin suppression in endothelial cells (ECs) and vascular smooth muscle cells (VSMCs), respectively. HGPSrev-Cdh5-CreERT2 mice were undistinguishable from HGPSrev mice with ubiquitous progerin expression, in contrast with the ameliorated progeroid phenotype of HGPSrev-SM22α-Cre mice. To study atherosclerosis, we generated atheroprone mouse models by overexpressing a PCSK9 gain-of-function mutant. While HGPSrev-Cdh5-CreERT2 and HGPSrev mice developed a similar level of excessive atherosclerosis, plaque development in HGPSrev-SM22α-Cre mice was reduced to wild-type levels. Our studies demonstrate that progerin suppression in VSMCs, but not in ECs, prevents exacerbated atherosclerosis in progeroid mice.

Updates on pharmacological treatment for Alzheimer's disease.

Alzheimer's disease (AD) is the most common cause of dementia, and its rising prevalence is constantly increasing the global health burden. There are currently no curative therapies for AD, and current treatment options provide only modest clinical benefit. Despite numerous clinical trials, there have been no major additions to the AD treatment armamentarium this century. The prevailing pathomechanistic hypothesis for AD begins with abnormal accumulation of amyloid β (Aβ) leading to plaque development, and disease-modifying candidate therapies have largely aimed to disrupt this process. Numerous clinical trials of monoclonal antibodies directed at various stages of Aβ plaque development have yielded mostly negative results; however, recent results suggest that a breakthrough may be on the horizon. The past two years have yielded positive results for three monoclonal antibodies (aducanumab, lecanemab, and donanemab) although questions remain regarding their clinical effectiveness. Additional clarity is needed to determine whether the clinical benefits are great enough to offset the treatment risks and the resource implications for healthcare systems. This review provides a foundational context and update on recent disease-modifying therapies for AD that have reached Phase III clinical trials. Up-to-date information on these therapies will help clinicians better inform their clinical decision-making and the counselling they can offer patients and their carers.

Repeated Injection of Very Small Superparamagnetic Iron Oxide Particles (VSOPs) in Murine Atherosclerosis: A Safety Study.

Citrate-coated electrostatically stabilized very small superparamagnetic iron oxide particles (VSOPs) have been successfully tested as magnetic resonance angiography (MRA) contrast agents and are promising tools for molecular imaging of atherosclerosis. Their repeated use in the background of pre-existing hyperlipidemia and atherosclerosis has not yet been studied. This study aimed to investigate the effect of multiple intravenous injections of VSOPs in atherosclerotic mice. Taurine-formulated VSOPs (VSOP-T) were repeatedly intravenously injected at 100 µmol Fe/kg in apolipoprotein E-deficient (ApoE KO) mice with diet-induced atherosclerosis. Angiographic imaging was carried out by in vivo MRI. Magnetic particle spectrometry was used to detect tissue VSOP content, and tissue iron content was quantified photometrically. Pathological changes in organs, atherosclerotic plaque development, and expression of hepatic iron-related proteins were evaluated. VSOP-T enabled the angiographic imaging of heart and blood vessels with a blood half-life of one hour. Repeated intravenous injection led to VSOP deposition and iron accumulation in the liver and spleen without affecting liver and spleen pathology, expression of hepatic iron metabolism proteins, serum lipids, or atherosclerotic lesion formation. Repeated injections of VSOP-T doses sufficient for MRA analyses had no significant effects on plaque burden, steatohepatitis, and iron homeostasis in atherosclerotic mice. These findings underscore the safety of VSOP-T and support its further development as a contrast agent and molecular imaging tool.