Regression Of Atherosclerosis Research Articles

IL-1β Inhibition Partially Negates the Beneficial Effects of Diet-Induced Atherosclerosis Regression in Mice.

Thromboembolic events secondary to rupture or erosion of advanced atherosclerotic lesions is the global leading cause of death. The most common and effective means to reduce these major adverse cardiovascular events, including myocardial infarction and stroke, is aggressive lipid lowering via a combination of drugs and dietary modifications. However, we know little regarding the effects of reducing dietary lipids on the composition and stability of advanced atherosclerotic lesions, the mechanisms that regulate these processes, and what therapeutic approaches might augment the benefits of lipid lowering. Smooth muscle cell lineage-tracing Apoe-/- mice were fed a high-cholesterol Western diet for 18 weeks and then a zero-cholesterol standard laboratory diet for 12 weeks before treating them with an IL (interleukin)-1β or control antibody for 8 weeks. We assessed lesion size and remodeling indices, as well as the cellular composition of aortic and brachiocephalic artery lesions, indices of plaque stability, overall plaque burden, and phenotypic transitions of smooth muscle cell and other lesion cells by smooth muscle cell lineage tracing combined with single-cell RNA sequencing, cytometry by time-of-flight, and immunostaining plus high-resolution confocal microscopic z-stack analysis. Lipid lowering by switching Apoe-/- mice from a Western diet to a standard laboratory diet reduced LDL cholesterol levels by 70% and resulted in multiple beneficial effects including reduced overall aortic plaque burden, as well as reduced intraplaque hemorrhage and necrotic core area. However, contrary to expectations, IL-1β antibody treatment after diet-induced reductions in lipids resulted in multiple detrimental changes including increased plaque burden and brachiocephalic artery lesion size, as well as increasedintraplaque hemorrhage, necrotic core area, and senescence as compared with IgG control antibody-treated mice. Furthermore, IL-1β antibody treatment upregulated neutrophil degranulation pathways but downregulated smooth muscle cell extracellular matrix pathways likely important for the protective fibrous cap. Taken together, IL-1β appears to be required for the maintenance of standard laboratory diet-induced reductions in plaque burden and increases in multiple indices of plaque stability.

Synergistic dual cell therapy for atherosclerosis regression: ROS-responsive Bio-liposomes co-loaded with Geniposide and Emodin

The development of nanomaterials for delivering natural compounds has emerged as a promising approach for atherosclerosis therapy. However, premature drug release remains a challenge. Here, we present a ROS-responsive biomimetic nanocomplex co-loaded with Geniposide (GP) and Emodin (EM) in nanoliposome particles (LP NPs) for targeted atherosclerosis therapy. The nanocomplex, hybridized with the macrophage membrane (Møm), effectively evades immune system clearance and targets atherosclerotic plaques. A modified thioketal (TK) system responds to ROS-rich plaque regions, triggering controlled drug release. In vitro, the nanocomplex inhibits endothelial cell apoptosis and macrophage lipid accumulation, restores endothelial cell function, and promotes cholesterol effluxion. In vivo, it targets ROS-rich atherosclerotic plaques, reducing plaque area ROS levels and restoring endothelial cell function, consequently promoting cholesterol outflow. Our study demonstrates that ROS-responsive biomimetic nanocomplexes co-delivering GP and EM exert a synergistic effect against endothelial cell apoptosis and lipid deposition in macrophages, offering a promising dual-cell therapy modality for atherosclerosis regression.

Allograft Model of Aortic Arch Segment Grafting to Abdominal Aorta Through End-to-Side Anastomosis in Mice.

The mouse aortic transplantation model is a valuable tool for investigating the mechanisms of atherosclerosis regression, but few laboratories can generate it due to the operation difficulty, especially for the style of end-to-side anastomosis, which facilitates syngeneic heterotopic transplanting a plaque-rich aortic arch into the abdominal aorta. Here we provide a modified protocol for generating this allograft model, which is capable of overcoming several critical surgical challenges such as separating a longer abdominal aorta segment, reducing bleeding and thrombosis, optimizing aortotomy, and improving end-to-side anastomosis to guarantee a potent graft. By transplanting plaque-rich aortic arches into the abdominal aorta of wildtype mice, a high operation success rate (over 90%) was noted with aortic clamping time under 60min, the graft potency was satisfactory evidenced by examinations of micro-CT, ultrasound, and lower limb blood flow measurement, while a significant atherosclerosis regression was observed in the grafts at 1week after transplantation.

Cluster of Differentiation-44-Targeting Prussian Blue Nanoparticles Onloaded with Colchicine for Atherosclerotic Plaque Regression in a Mice Model.

Atherosclerosis management heavily relies on the suppression of the inflammatory response of macrophages. Colchicine's potent anti-inflammatory properties make it a promising candidate for secondary prevention against cardiovascular disease. However, its high toxicity and numerous adverse effects limit its clinical use. To address this, there is an urgent need for specific drug delivery systems to boost the level of accumulation of colchicine within atherosclerotic plaques. In this study, the cluster of differentiation-44 receptor was verified to be overexpressed in inflammatory macrophages within plaques both in vitro and in vivo. Subsequently, a Prussian blue-based nanomedical loading system with hyaluronic acid (HA) coating was constructed, and its effects were observed on the atherosclerosis regression. Colchicine and Cy5.5 were encapsulated within Prussian blue nanoparticles through self-assembly, followed by conjugation with hyaluronic acid to create col@PBNP@HA. The formulated col@PBNP@HA displayed a cubic shape and scattered distribution. Importantly, col@PBNP@HA demonstrated specific cellular uptake into lipopolysaccharide-stimulated macrophages. In vitro experiments showed that col@PBNP@HA more effectively inhibited expression of inflammatory factors and scavenged reactive oxygen species compared with the control group, which were treated with colchicine. Furthermore, col@PBNP@HA exhibited its specific and higher accumulation in aortic plaque analysis via fluorescence imaging of aortas. After 4 weeks, administration of col@PBNP@HA resulted in significant atherosclerosis regression in the mice model, with therapeutic effects superior to those of free colchicine. Similar to colchicine, col@PBNP@HA inhibited the secretion of inflammation factors and scavenged ROS through the regulation of the toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (Myd88)/nuclear factor kappa-B (NF-κB) and peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α) signaling pathway. In summary, col@PBNP@HA demonstrated specific targeting ability to inflammatory plaques and exerted beneficial effects on atherosclerosis regression through TLR4/Myd88/NF-κB and PGC-1α modulation.

Trehalose promotes atherosclerosis regression in female mice.

Atherosclerosis is a chronic inflammatory disease caused by the deposition of lipids within the artery wall. During atherogenesis, efficient autophagy is needed to facilitate efferocytosis and cholesterol efflux, limit inflammation and lipid droplet buildup, and eliminate defective mitochondria and protein aggregates. Central to the regulation of autophagy is the transcription factor EB (TFEB), which coordinates the expression of lysosomal biogenesis and autophagy genes. In recent years, trehalose has been shown to promote TFEB activation and protect against atherogenesis. Here, we sought to investigate the role of autophagy activation during atherosclerosis regression. Atherosclerosis was established in C57BL/6N mice by injecting AAV-PCSK9 and 16 weeks of Western diet feeding, followed by switching to a chow diet to induce atherosclerosis regression. During the regression period, mice were either injected with trehalose concomitant with trehalose supplementation in their drinking water or injected with saline for 6 weeks. Female mice receiving trehalose had reduced atherosclerosis burden, as evidenced by reduced plaque lipid content, macrophage numbers and IL-1β content in parallel with increased plaque collagen deposition, which was not observed in their male counterparts. In addition, trehalose-treated female mice had lower levels of circulating leukocytes, including inflammatory monocytes and CD4+ T cells. Lastly, we found that autophagy flux in male mice was basally higher than in female mice during atherosclerosis progression. Our data demonstrate a sex-specific effect of trehalose in atherosclerosis regression, whereby trehalose reduced lipid content, inflammation, and increased collagen content in female mice but not in male mice. Furthermore, we discovered inherent differences in the autophagy flux capacities between the sexes: female mice exhibited lower plaque autophagy than males, which rendered the female mice more responsive to atherosclerosis regression. Our work highlights the importance of understanding sex differences in atherosclerosis to personalize the development of future therapies to treat cardiovascular diseases.

Metabolic changes with the occurrence of atherosclerotic plaques and the effects of statins.

Atherosclerosis is a common cardiovascular disease caused by the abnormal expression of multiple factors and genes influenced by both environmental and genetic factors. The primary manifestation of atherosclerosis is plaque formation, which occurs when inflammatory cells consume excess lipids, affecting their retention and modification within the arterial intima. This triggers endothelial cell (EC) activation, immune cell infiltration, vascular smooth muscle cell (VSMC) proliferation and migration, foam cell formation, lipid streaks, and fibrous plaque development. These processes can lead to vascular wall sclerosis, lumen stenosis, and thrombosis. Immune cells, ECs, and VSMCs in atherosclerotic plaques undergo significant metabolic changes and inflammatory responses. The interaction of cytokines and chemokines secreted by these cells leads to the onset, progression, and regression of atherosclerosis. The regulation of cell- or cytokine-based immune responses is a novel therapeutic approach for atherosclerosis. Statins are currently the primary pharmacological agents utilised for managing unstable plaques owing to their ability to enhance endothelial function, regulate VSMC proliferation and apoptosis by reducing cholesterol levels, and mitigate the expression and activity of inflammatory cytokines. In this review, we provide an overview of the metabolic changes associated with atherosclerosis, describe the effects of inflammatory responses on atherosclerotic plaques, and discuss the mechanisms through which statins contribute to plaque stabilisation. Additionally, we examine the role of statins in combination with other drugs in the management of atherosclerosis.

Antifungal, Antioxidant, Antimicrobial, Antinociceptive, Cytotoxic, Hypolipidemic, Antihypertensive, Antispasmodic Properties of Apiaceae Family of Seeds

Susceptibility to vasoconstriction in response to activation of platelets and leukocytes is reduced or abolished by regression of atherosclerosis. Design and Place of conduction: The research work was single blind placebo-controlled, conducted at Jinnah Hospital, Lahore. Research time: It was conducted from AUGUST TO NOVEMBER 2018. Number of patients and their Age: Seventy five already diagnosed primary and secondary hyperlipidemic patients were selected with age range from 17 to 65 years. Exclusion criteria: Diabetes mellitus, cigarette smoking/alcohol addictive patients, peptic ulcer disease, hypothyroidism, kidney dysfunction, any heart disease and liver disease. All patients were divided in three groups (group-I, group-II, group-III), 25 in each group. Proforma for patients: Their baseline lipid profile data were taken and filed in specifically designed Performa, at start of taking medicine. Patients group division: Twenty five patients of group-I were advised to take 10 grams of Flaxseeds in three divided doses after meal. Twenty five patients of group-II were advised to take Ajwain seeds 10 grams in three divided doses after each meal for two months. Twenty five patients of group-III were provided placebo capsules, (containing grinded rice), taking one capsule after each meal. All participants were advised to take these medicines for eight weeks. Followup period: All participants were called fortnightly for their query and follow up. Their LDL-cholesterol, and HDL-cholesterol was determined at the hospital laboratory. Results: In two months therapy by Flaxseeds decreased LDL-cholesterol from 195.11±2.11 mg/dl to 190.22±3.11 mg/dl, which is significant statistically. HDL was increased from 34.53±1.65 mg/dl to 38.97±2.29 mg/d, which is also significant change. In two months therapy by AJWAIN, LDL-c reduced from 201.51±2.62 mg/dl to 197.11±2.66 mg/dl, which is significant statistically. HDL-cholesterol increased by Ajwain from 36.97±3.32 mg/dl to 37.45±1.87 mg/dl, which is insignificant statistically. While flaxseed hasn't yet been shown to improve heart disease risk, there's good evidence that flaxseed and flaxseed oil may lower cholesterol levels. Groundflaxseed -- but not flaxseed oil -- may also help with menopausal symptoms.

Frequency, predictors and clinical outcomes of AMI patients with triple regression of coronary atherosclerosis: A sub-analysis of the PACMAN AMI trial

Abstract Background Recent studies have shown that coronary artery disease regression is not limited to atheroma reduction but also includes plaque stabilization in patients treated with high-intensity lipid-lowering therapy. The frequency and characteristics of patients who simultaneously show atheroma volume reduction and plaque stabilization defined as reduction in plaque lipid content and increase in fibrous cap thickness (i.e., triple regression) are unknown. Purpose This study sought to determine the percentage and determinants of both plaque volume reduction and plaque stabilization in patients with acute myocardial infarction (MI) and treated wiTh alirocumab or placebo added to high-intensity statin therapy. Methods The PACMAN-AMI trial employed serial intravascular ultrasound, near-infrared spectroscopy and optical coherence tomography to compare the effects of alirocumab vs. placebo (1:1) in 265 patients (537 non–infarct-related coronary arteries) receiving high-intensity statin therapy. Triple regression was defined by the combined presence of reduction in percent atheroma volume (PAV), reduction in maximum lipid core burden index (maxLCBI4mm) and increase in minimal fibrous cap thickness (FCT). Clinical outcomes of patients with or without triple regression were assessed at one year follow-up. Results Overall, 199 (75.1%) patients showed PAV reduction, 180 (67.7%) maxLCBI4mm reduction and 172 (77.6%) minimal FCT increase, with a total of 84 (31.7%) patients having triple regression (40.8% in the alirocumab group vs. 23.0% in the placebo group, p=0.002). The percentage of patients with triple regression was similar among the groups with PAV reduction, maxLCBI4mm reduction or minimal FCT thickening (42%, 51% or 49%, respectively, p=0.30). Similar baseline clinical features and a higher reduction in low-density lipoprotein cholesterol (LDL-C, -27.1 [37.7 to -16.6] mg/dl, p<0.001) and apolipoprotein B levels (-18.5 [-26.0 to -11.0] p<0.001) were observed patienst with vs. without triple regression. A higher reduction in PAV (-1.54 [-2.14 to -0.95] %, p<0.001), maxLCBI4mm (-111.24 [-140.46 to -82.02], p<0.001) and a higher increase in minimal FCT (56.39 [38.67 to 74.11] µm, p<0.001) were found in patients with triple regression. At multivariable analysis, factors independently associated with triple regression included higher baseline maxLCBI4mm (1.03, 1.01 to 1.06, p=0.013) and alirocumab treatment (2.83, 1.57 to 5.16, p=0.001). The composite clinical endpoint of death, MI and ischemia-driven revascularization occurred less frequently in patients with versus without triple regression (8.3% vs 18.2%, p=0.042). Conclusions Triple regression occurred among one third of acute AMI patients receiving high-intensity lipid lowering therapy. Alirocumab treatment and higher baseline lipid accumulation were independent predictors of triple regression. Triple regression was associated with a reduced rate of adverse cardiovascular events.

Abstract 12520: Advancements in the Treatment of Atherosclerosis

Background: Endotheliotoxic hyperlipidemia provide impaired eNOS derived NO production, excessive free-radicals, adhesive molecule generation, vascular lipid accumulation, atherosclerosis development & progression. NO replacement by NO donors can restore NO deficit. HDLs have anti-atherogenic properties and are carriers of excessive cellular cholesterol via reverse cholesterol transport (RCT) pathway. Lipoprotein enrichment by anionic phosphatidylinositol (PI) increases the negative surface potential of lipoproteins and stimulate RCT. PI stimulates rapid flux and clearance of plasma choles-l by increased hepatic uptake. Objective: Regression of atherosclerosis stimulating RCT with experimental combination of NO donor in PI nanocapsules (AlphaX1). Methods: 30 rabbits fed with 2%cholesterol diet for 6 months After 6 m subdivided in 3 groups. G1-10 without treatment. G2-treated with AlphaX1 for 10 days, G3-treated for 20 days. 5 rabbits-control. Animals sacrificed after 10 and 20 days of treatment. Abdominal aorta, part snap frozen in cryostat-OilRedO staining, part exposed for morphology and electron microscopy. Results: Morphology (x100-x27000): G1-numerous vacuoles with neutral lipids and foam cells under endothelium, proliferation of solitary smooth muscle cells containing lipid vacuoles; G2-moderate deposition of lipid vacuoles & foam cells in sub-endothelium, restoration of endothelium. G3-express reduction of lipid vacuoles & foam cells, restoration of elastic fibers, regeneration of endothelium.OilRedO, C 1.4±0.2% G1 38.2±3.6%. G2 7.3±0.8%, G3 2.3±0.6%. Conclusion: Data shows evidence that AlphaX1 provide regeneration of endothelial cells, restoration of elastic fibers (probably due to regulation of fibulin5 by PI3K/Akt), anti-inflammatory effect, clearance of foam cells from neutral lipids and regression of atherosclerosis. AlphaX1 provide antiatherogenic properties of NO and PI, probably by reduction in cytokines production, decrease in adhesion molecules expression, monocyte-endothelium adhesion inhibition, increased cholesterol efflux and plasma clearance via hepatic uptake. AlphaX1 could be a potential new therapeutic agent for prophylaxis & treatment of hyperlipidemia and atherosclerosis.

The Role of Macrophages in Atherosclerosis: Participants and Therapists.

Currently, atherosclerosis, characterized by the dysfunction of lipid metabolism and chronic inflammation in the intimal space of the vessel, is considered to be a metabolic disease. As the most abundant innate immune cells in the body, macrophages play a key role in the onset, progression, or regression of atherosclerosis. For example, macrophages exhibit several polarization states in response to microenvironmental stimuli; an increasing proportion of macrophages, polarized toward M2, can suppress inflammation, scavenge cell debris and apoptotic cells, and contribute to tissue repair and fibrosis. Additionally, specific exosomes, generated by macrophages containing certain miRNAs and effective efferocytosis of macrophages, are crucial for atherosclerosis. Therefore, macrophages have emerged as a novel potential target for anti-atherosclerosis therapy. This article reviews the role of macrophages in atherosclerosis from different aspects: origin, phenotype, exosomes, and efferocytosis, and discusses new approaches for the treatment of atherosclerosis.

A cardiovascular polypill for secondary stroke prevention in a tertiary centre in Ghana (SMAART): a phase 2 randomised clinical trial

A cardiovascular polypill containing generic drugs might facilitate sustained implementation of and adherence to evidence-based treatments, especially in resource-limited settings. However, the impact of a cardiovascular polypill in mitigating atherosclerotic risk among stroke survivors has not been assessed. We aimed to compare a polypill regimen with usual care on carotid intima-media thickness (CIMT) regression after ischaemic stroke. In SMAART, a phase 2 parallel, open-label, assessor-masked, randomised clinical trial, we randomly allocated individuals (aged ≥18 years) who had an ischaemic stroke within the previous 2 months, using a computer-generated randomisation sequence (1:1), to either a polypill or usual care group at a tertiary centre in Ghana. The polypill regimen was a fixed-dose pill containing 5 mg ramipril, 50 mg atenolol, 12·5 mg hydrochlorothiazide, 20 mg simvastatin, and 100 mg aspirin administered as two capsules once per day for 12 months. Usual care was tailored guideline-recommended secondary prevention medications. The primary outcome was the change in CIMT over 12 months with adjustment for baseline values, compared using ANCOVA in all participants with complete data at month 12. Safety was analysed in all randomly assigned participants. This trial is registered at ClinicalTrials.gov, NCT03329599, and is completed. Between Feb 12, 2019, and Dec 4, 2020, we randomly assigned 148 participants (74 to the usual care group and 74 to the polypill group), 74 (50%) of whom were male and 74 (50%) female. CIMT was assessed in 62 (84%) of 74 participants in the usual care group and 59 (80%) of 74 participants in the polypill group; the main reason for loss to follow-up was participants not completing the study. The mean CIMT change at month 12 was -0·092 mm (95% CI -0·130 to -0·051) in the usual care group versus -0·017 mm (-0·067 to 0·034) in the polypill group, with an adjusted mean difference of 0·049 (-0·008 to 0·109; p=0·11). Serious adverse events occurred among two (3%) participants in the usual care group, and eight (11%) participants in the polypill group (p=0·049). The polypill regimen resulted in similar regression in subclinical atherosclerosis and many secondary and tertiary outcome measures as the tailored drug regimen, but with more serious adverse events. Larger, longer-term, event-based studies, including patients with stroke in primary care settings, are warranted. US National Institutes of Health. For the Akan (Twi) translation of the abstract see Supplementary Materials section.

Adipokines in atherosclerosis: unraveling complex roles.

Adipokines are biologically active factors secreted by adipose tissue that act on local and distant tissues through autocrine, paracrine, and endocrine mechanisms. However, adipokines are believed to be involved in an increased risk of atherosclerosis. Classical adipokines include leptin, adiponectin, and ceramide, while newly identified adipokines include visceral adipose tissue-derived serpin, omentin, and asprosin. New evidence suggests that adipokines can play an essential role in atherosclerosis progression and regression. Here, we summarize the complex roles of various adipokines in atherosclerosis lesions. Representative protective adipokines include adiponectin and neuregulin 4; deteriorating adipokines include leptin, resistin, thrombospondin-1, and C1q/tumor necrosis factor-related protein 5; and adipokines with dual protective and deteriorating effects include C1q/tumor necrosis factor-related protein 1 and C1q/tumor necrosis factor-related protein 3; and adipose tissue-derived bioactive materials include sphingosine-1-phosphate, ceramide, and adipose tissue-derived exosomes. However, the role of a newly discovered adipokine, asprosin, in atherosclerosis remains unclear. This article reviews progress in the research on the effects of adipokines in atherosclerosis and how they may be regulated to halt its progression.

Early stage atherosclerosis regression using combined encapsulated docetaxel nanoparticles- mediated ultrasound sonoporation therapy and gold nanoparticles- mediated X- rays- based Auger electron therapy

Early stage atherosclerosis regression using combined encapsulated docetaxel nanoparticles- mediated ultrasound sonoporation therapy and gold nanoparticles- mediated X- rays- based Auger electron therapy

The Role of Macrophages in Atherosclerosis: Pathophysiologic Mechanisms and Treatment Considerations.

Atherosclerotic diseases are a leading cause of morbidity and mortality worldwide, despite the recent diagnostic and therapeutic advances. A thorough understanding of the pathophysiologic mechanisms is thus essential to improve the care of affected individuals. Macrophages are crucial mediators of the atherosclerotic cascade, but their role has not been fully elucidated. The two main subtypes, tissue-resident and monocyte-derived macrophages, have distinct functions that contribute to atherosclerosis development or regression. Since polarization of macrophages to an M2 phenotype and induction of macrophage autophagy have been demonstrated to be atheroprotective, targeting these pathways could represent an appealing approach. Interestingly, macrophage receptors could act as drug targets, as seen in recent experimental studies. Last but not least, macrophage-membrane-coated carriers have been investigated with encouraging results.

Exercise-induced endothelial Mecp2 lactylation suppresses atherosclerosis via the Ereg/MAPK signalling pathway

Background and aimsLactylation, a recently identified post-translational modification (PTM), plays a central role in the regulation of multiple physiological and pathological processes. Exercise is known to provide protection against cardiovascular disease. However, whether exercise-generated lactate changes lactylation and is involved in the exercise-induced attenuation of atherosclerotic cardiovascular disease (ASCVD) remains unclear. The purpose of this study was to investigate the effects and mechanisms of exercise-induced lactylation on ASCVD. Methods and ResultsUsing the high-fat diet-induced apolipoprotein-deficient mouse model of ASCVD, we found that exercise training promoted Mecp2 lysine lactylation (Mecp2k271la); it also decreased the expression of vascular cell adhesion molecule 1 (Vcam-1), intercellular adhesion molecule 1 (Icam-1), monocyte chemoattractant protein 1 (Mcp-1), interleukin (IL)-1β, IL-6, and increased the level of endothelial nitric oxide synthase (Enos) in the aortic tissue of mice. To explore the underlying mechanisms, mouse aortic endothelial cells (MAECs) were subjected to RNA-sequencing and CHIP-qPCR, which confirmed that Mecp2k271la repressed the expression of epiregulin (Ereg) by binding to its chromatin, demonstrating Ereg as a key downstream molecule for Mecp2k271la. Furthermore, Ereg altered the mitogen-activated protein kinase (MAPK) signalling pathway through regulating the phosphorylation level of epidermal growth factor receptor, thereby affecting the expression of Vcam-1, Icam-1, Mcp-1, IL-1β, IL-6, and Enos in ECs, which in turn promoted the regression of atherosclerosis. In addition, increasing the level of Mecp2k271la by exogenous lactate administration in vivo also inhibits the expression of Ereg and the MAPK activity in ECs, resulting in repressed atherosclerotic progression. ConclusionsIn summary, this study provides a mechanistic link between exercise and lactylation modification, offering new insight into the anti-atherosclerotic effects of exercise-induced PTM.

Abstract 704: Autophagy Activation Promotes Atherosclerosis Regression

Atherosclerosis is characterized by the deposition of cholesterol-rich plaques within the artery wall that are primarily comprised of macrophage and vascular smooth muscle cell (VSMC) foam cells. Atherogenesis is associated with a progressive defect in autophagy, a cell process that promotes cellular cholesterol homeostasis by degrading excess lipids and promoting cholesterol efflux. We recently showed that during atherosclerosis progression, autophagy and cholesterol efflux to HDL was particularly defective in VSMC foam cells as compared to macrophage foam cells. While previous studies have shown that autophagy activation of transcription factor EB by trehalose protects against atherosclerosis, the ability of this therapeutic compound to shrink pre-existing atherosclerotic plaque (atherosclerosis regression ) is unknown. We hypothesized that activating autophagy with trehalose would promote atherosclerosis regression in mice by enhancing macrophage and VSMC reverse cholesterol transport. Mice were injected with a gain of function PCSK9 adeno-associated virus and fed a Western Diet for 16 weeks to promote atherosclerotic plaque progression, followed by a switch to chow diet for 6 weeks to induce plaque regression. During the regression phase, mice received sub-cutaneous injections of saline or trehalose biweekly. Aortic sinuses were evaluated for changes in plaque size and lipid content. Circulating immune cells were quantified by flow cytometry. A switch to chow diet decreased circulating inflammatory and patrolling monocytes as compared to baseline, although no changes between the trehalose and saline treatment groups were observed. Oil Red O staining revealed a decrease in plaque lipid content in trehalose-treated mice as compared to the saline group, suggesting that autophagy activation in mice during atherosclerosis regression promotes favorable plaque remodeling. Our data demonstrates the therapeutic potential of autophagy activation in reducing atherosclerotic plaque burden. Further analysis of autophagy and inflammatory markers to characterize the mechanisms by which trehalose improves atherosclerosis regression is ongoing.

Abstract 305: Dietary β-carotene Accelerates Atherosclerotic Resolution By Promoting Treg Expansion In The Atherosclerosis Lesion

Forkhead box P3 ( FoxP3 ) + regulatory T cells (Tregs) mediate atherosclerosis resolution and regression by promoting an anti-inflammatory environment in the lesion. FoxP3 is upregulated by retinoic acid, the active form of vitamin A, but whether vitamin A status influences atherosclerosis resolution remains unexplored. We hypothesized that β-carotene, the main vitamin A precursor in human diet, accelerates atherosclerosis resolution by upregulating FoxP3 expression to promote Treg expansion. We induced atherosclerosis in FoxP3 EGFP mice fed Western diet control (WD-Control) and injected with an anti-sense oligonucleotide targeting the LDLR (ASO-LDLR) for 16 weeks. After this period, we harvested a subset of mice as Baseline, while the remaining mice underwent atherosclerosis resolution upon the interruption of ASO-LDLR infusions to recover LDLR expression and normalize plasma lipids for a period of three weeks. During this time, mice either continued on the same WD-Control or were switched to a Western diet supplemented with 50 mg of β-carotene/kg of diet (WD- β-carotene). To examine the implication of Tregs, we injected a subset of WD-β-carotene with anti-CD25 (WD-β-carotene + anti-CD25), while WD-Control and a second subset of WD- β-carotene mice were injected with IgG control. We estimated atherosclerosis resolution by quantifying macrophage and collagen contents in the lesions present at the level of the aortic root. WD-β-carotene-fed mice injected with IgG showed a reduction in macrophage content accompanied by an increase in collagen in comparison to all the remaining groups, while WD-β-carotene + anti-CD25 lesions resembled those present in WD-Control mice. We examined Treg the relative number of CD25 + FoxP3 + and CD25 - FoxP3 + cells in the spleen, blood, and the lesion. CD25 + FoxP3 + numbers decreased in response to anti-CD25 infusions in all the tissues examined. Dietary β-carotene favored an increase of 269% and 653% in CD25 - FoxP3 + Tregs in comparison to the Baseline of WD-Control groups, respectively. These effects occurred independently of changes in plasma lipids or changes in body weight. Our data show that β-carotene supplementation results in Treg expansion and acceleration of atherosclerosis resolution by increasing Treg number.

Abstract 307: Targeted Activation Of The Tnfa Pathway Accelerates Atherosclerosis Regression In Mice

Aggressive lipid lowering in mice with established atherosclerosis induces plaque regression and is characterized by reduced monocyte recruitment and increased expression of the motility receptor C-C chemokine receptor 7 (CCR7) to promote macrophage egress from plaques to nearby lymph nodes. Notably, genetic deletion of receptors critical for the recruitment of inflammatory Ly6C high monocytes is necessary to facilitate plaque regression. Our group previously showed that deletion of macrophage LDL receptor-related protein 1 (LRP1) in mice with established atherosclerosis accelerates plaque regression after lipid lowering and is associated with increased inflammation and macrophage CCR7-mediated egress. We tested the hypothesis that targeted activation of inflammation following lipid lowering in atherosclerotic mice accelerates atherosclerosis regression. LC-MS/MS proteomics performed on murine macrophages revealed that the loss of LRP1 upregulated the inflammatory protein tumor necrosis factor alpha (TNFα) 1.48-fold (P<0.05). Apoe -/- mice were fed a Western diet for 12 weeks to establish atherosclerosis and then subjected to bone marrow transplantation (BMT) using wildtype ( Apoe +/+ ) mice as donors to restore plasma APOE and reduce lipids. A cohort was sacrificed two weeks after BMT and used as baseline (N=11). The remaining mice (N=12/group) received intraperitoneal injections of recombinant murine TNFα (0.075mg/kg/day) or saline for 6 weeks on chow diet. After 6 weeks on chow diet, total plasma cholesterol levels ranged 82 -120 mg/dL with no significant differences between treatment cohorts. TNFα-treated mice had elevated spleen-to-body weight ratios compared to saline treated controls (P<0.0001), confirming successful activation of the immune system. Following 6 weeks of lipid lowering, TNFα treatment reduced total plaque area and lipid content 17.0% (P<0.05) and 34.4% (P<0.05), respectively, compared to saline treated controls (P<0.05).Herein, we show that the administration of TNFα, to stimulate inflammation after lipid lowering, significantly reduces plaque size and plaque lipid content in mice with established atherosclerosis.

Abstract 160: Atherosclerosis Regression At The Single-Cell Level

Atherosclerosis is a chronic inflammatory disease, but lipid-lowering therapies continue to be the standard of care, and substantial regression of human atheromata remains an elusive goal. To address this gap, our lab has devised multiple models to achieve plaque regression in atherosclerotic mice using genetic or RNA-based approaches. Here, we set out to learn how the immune cell composition of murine plaques changes with the induction of a regression phenotype irrespective of model. To achieve this, we performed single cell RNA-seq on CD45 + leukocytes from the aortic arch plaques of Ldlr -/- mice fed an atherogenic diet (baseline progression) and from two additional cohorts that were switched to control chow following atherogenesis and either treated with antisense oligonucleotides targeting ApoB (regression) or not (halted progression). The resultant transcriptomic data were integrated with those from our previous regression studies in a batch-corrected manner to distill the common features of atherosclerosis regression. This approach yielded a dataset of 35,996 cells, a degree of granularity one order of magnitude higher than that of the average comparable study, which allowed us to draw a comprehensive picture of the lymphoid and myeloid transcriptional dynamics that give rise to pro-resolving phenotypes. Specifically, we found two novel macrophage populations with distinct transcriptional profiles and unique distribution across conditions that nonetheless shared the same differentiation path. The first was characteristic of the halted progression groups and showed upregulation of genes involved in oxidative phosphorylation; the other was enriched in regression and displayed a transcriptional program consistent with plaque remodeling by means of efferocytosis and cholesterol efflux. Our findings suggest that pro-resolving macrophage fate acquisition in regression occurs at the expense of a separate, potentially pro-inflammatory lineage. A deeper understanding of the molecular and cellular purview of these pro-resolving macrophages as well as the ontogenic path of bone marrow monocytes toward that fate would contribute to the development of anti-inflammatory therapies to treat and prevent atherosclerosis.

A comprehensive review of healthy effects of vegetarian diets

AimsA comprehensive review comparing the effect of vegetarian (V) and non-vegetarian (NV) diets on the major cardiometabolic diseases’ outcomes was performed. Data synthesisWe performed literature research (up to December 31, 2022) of the evidence separately for vascular disease (VD), obesity (OB), dyslipidemia (Dysl), hypertension (HPT), type 2 diabetes (T2D), metabolic syndrome (MetS), analyzing only cohort studies and randomized controlled studies (RCTs) and comparing the effect of V and NV diets. Cohort studies showed advantages of V diets compared to NV diets on incidence and/or mortality risk for ischemic heart disease, overweight and OB risk. Most cohort studies showed V had lower risk of HPT and lower blood pressure (BP) than NV and V diets had positive effects on T2D risk or plasma parameters. The few cohort studies on the risk of MetS reported mixed results. In RCTs, V diets, mainly low-fat-vegan ones, led to greater weight loss and improved glycemic control than NV diets and in the only one RCT a partial regression of coronary atherosclerosis. In most RCTs, V diets significantly reduced LDL-C levels (but also decreased HDL-C levels) and BP. ConclusionsIn this comprehensive review of the association between V diets and cardiometabolic outcomes, we found that following this type of diet may help to prevent most of these diseases. However, the non-uniformity of the studies, due to ethnic, cultural, and methodological differences, does not allow for generalizing the present results and drawing definitive conclusions. Further, well-designed studies are warranted to confirm the consistency of our conclusions.