Reduced Plaque Burden Research Articles

Effects of Berries, Phytochemicals, and Probiotics on Atherosclerosis through Gut Microbiota Modification: A Meta-Analysis of Animal Studies

Atherosclerosis is a major cause of death and disability. The beneficial effects of phytochemicals and probiotics on atherosclerosis have gained significant interest since these functional foods can improve inflammation, oxidative stress, and microbiome dysbiosis. The direct effect of the microbiome in atherosclerosis, however, needs further elucidation. The objective of this work was to investigate the effects of polyphenols, alkaloids, and probiotics on atherosclerosis using a meta-analysis of studies with mouse models of atherosclerosis. Identification of eligible studies was conducted through searches on PubMed, Embase, Web of Science, and Science Direct until November 2022. The results showed that phytochemicals reduced atherosclerosis, which was significant in male mice, but not in females. Probiotics, on the other hand, showed significant reductions in plaque in both sexes. Berries and phytochemicals modulated gut microbial composition by reducing the Firmicutes/Bacteroidetes (F/B) ratio and by upregulating health-promoting bacteria, including Akkermansia muciniphila. This analysis suggests that phytochemicals and probiotics can reduce atherosclerosis in animal models, with a potentially greater effect on male animals. Thus, consumption of functional foods rich in phytochemicals as well as probiotics are viable interventions to improve gut health and reduce plaque burden in patients suffering from cardiovascular disease (CVD).

Abstract 13560: System Gene Regulatory Network-Based Drug Repurposing Combined With Preclinical Molecular Imaging Identifies Anti-Atherosclerotic Properties of Auranofin

Introduction: The identification of new treatments for atherosclerosis (ACVD), a common complex disease, is a daunting task because sets of genes, rather than individual genes, control cell functions. Using systems genetics, our team identified gene regulatory network (GRN42) that is active in the human atherosclerotic arterial wall and is involved in the regulation of foam cell formation. Hypothesis: A network-driven drug repurposing approach combined with rigorous preclinical validation will identify new uses for existing drugs to treat ACVD. Methods: We developed a GRN42-based computational drug repurposing pipeline to infer new uses for existing drugs. Selected compounds were screened by measuring their ability to inhibit foam cell formation in vitro using THP-1-derived macrophages. The in vivo efficacy was validated in ApoE-/- mice fed a western diet by histology and in atherosclerotic rabbits using histology and non-invasive 18 F-FDG PET-MR imaging. Results: 30 candidate compounds were predicted to influence the function of GRN42 and 5 were selected for in vitro screening based on their prediction scores (Figure 1A). As expected, vitamin D reduced cholesteryl esters accumulation in foam cells. Auranofin, and FDA-approved drug for rheumatoid arthritis reduced foam cell formation. As predicted methyl-fasudil had no effect, while nicardipine and flutamide increased foam cell formation (Figure 1B). Auranofin reduced plaque burden in ApoE-/- mice (Figure 1C) and in rabbits reduced lipid accumulation (Figure 1D) and inflammation shown as reduced 18 F-FDG uptake in the arterial wall (Figure 1E). Conclusions: Our results provide robust evidence that a GRN-based computational drug repurposing approach, when combined with robust preclinical validation using translational molecular imaging, can successfully identify new uses of existing drugs for the treatment of ACVD.

Guanmaitong Granule Attenuates Atherosclerosis by Inhibiting Inflammatory Immune Response in ApoE-/- Mice Fed High-Fat Diet.

BackgroundAtherosclerosis (AS) is the leading cause of cardiovascular diseases, such as myocardial infarction and stroke. Guanmaitong granule (GMTG) is a TCM (Traditional Chinese medicine) prescribed to treat AS. However, its mechanism remains unclear.MethodsWe obtained reliable ingredients and targets of GMTG using the HERB database. AS-related targets were obtained from HERB and GeneCards databases. The target database was constructed by intersecting the ingredients of GMTG with the AS-related targets. STRING and Cytoscape were used to create protein-protein interaction (PPI) network and screen core targets. GO enrichment analysis and KEGG pathway analyses were performed using R. Finally, the ApoE−/− mice AS model was induced by a high-fat diet (HFD) for in vivo validation of core pathways and targets.ResultsA total of 124 ingredients and 418 potential targets of GMTG for treating AS were obtained. Numerous ingredients and targets were related to Panax notoginseng, Salvia miltiorrhiza, and Astragalus. Most core targets and pathways were involved in the inflammatory immune response. GMTG could decrease serum triglycerides, total cholesterol, low-density lipoprotein-cholesterol, and oxidized low-density lipoprotein level and increase the serum high-density lipoprotein-cholesterol level. Furthermore, GMTG reduced the plaque burden and promoted plaque remodeling by reducing plaque area, lipid deposition, foam cell content, and collagen fiber content in the plaque in the aortic root of ApoE−/− mice. GMTG inhibited systemic and plaque inflammatory immune response and increased plaque stability by inhibiting the excessive release of the TLR4/MyD88/NF-κB pathway-induced inflammatory cytokines, tumor necrosis factor, interleukin-6, and interleukin-1 beta.ConclusionRadix notoginseng, Radix salviae liguliobae, and Radix astragali are the main ingredients of GMTG for treating AS. Further, GMTG could regulate the level of serum lipids and inhibit inflammatory immune response, which resulted in anti-AS effects such as plaque stabilization, reduction of plaque burden, and plaque remodeling. GMTG is a promising multi-target treatment for AS.

Endothelial NCK2 promotes atherosclerosis progression in male but not female Nck1-null atheroprone mice

A better understanding of endothelial dysfunction holds promise for more effective interventions for atherosclerosis prevention and treatment. Endothelial signaling by the non-catalytic region of the tyrosine kinase (NCK) family of adaptors, consisting of NCK1 and NCK2, has been implicated in cardiovascular development and postnatal angiogenesis but its role in vascular disease remains incompletely understood. Here, we report stage- and sex-dependent effects of endothelial NCK2 signaling on arterial wall inflammation and atherosclerosis development. Male and female Nck1-null atheroprone mice enabling inducible, endothelial-specific Nck2 inactivation were fed a high fat diet (HFD) for 8 or 16 weeks to model atherosclerosis initiation and progression, respectively. Analysis of aorta preparations en face during disease progression, but not initiation, showed a significant reduction in plaque burden in males, but not females, lacking endothelial NCK2 relative to controls. Markers of vascular inflammation were reduced by endothelial NCK2 deficiency in both males and females during atherosclerosis progression but not initiation. At advanced stages of disease, plaque size and severity of atherosclerotic lesions were reduced by abrogation of endothelial NCK2 signaling only in males. Collectively, our results demonstrate stage- and sex-dependent modulation of atherosclerosis development by endothelial NCK2 signaling.

Gallic Acid Reduces Plaque Burden in Male Mice

ObjectivesTo determine if GA reduces plaque in a sex-dependent manner in atherosclerotic mice. Additionally, whether plaque burden correlates to changes in cholesterol (CHO) and inflammation. MethodsMale and female atherosclerotic (ApoE–/–) mice 3–4 months old (8/group) were treated with or without 0.2% GA in drinking water and chow diet for 2 weeks, then switched to high-fat diet (HFD) with and without GA for 5 weeks. Blood and aorta were collected for CHO and liver inflammation (AST, ALT) marker and en face plaque analysis, respectively. Livers and spleens were also collected and weighed; a higher weight associated with heightened inflammation. ResultsMales but not females receiving GA plus HFD had reduced plaque burden vs. HFD controls. Both the arch (p = 0.012) and descending (0.0017) portions of male aortas had reductions. GA did not reduce CHO, AST, ALT or liver weight, but reduced spleen weight in males and females. These data suggest GA reduces inflammation to attenuate plaque accumulation in males. ConclusionsThis study determined GA attenuated atherosclerosis in male but not female mice, and changes were independent of CHO, liver inflammation but corresponded with a reduction in spleen mass and inflammation. Findings are significant and suggest therapeutic potential because a prior study supplementing blackberries rich in GA reduced plaque in male mice, but this result could have been due to other components such as fiber. Funding SourcesUSDA and the Florida Department of Health (FDOH).

Abstract 521: Parkin Has Non-canonical Roles In Macrophage Lipid Metabolism With Effects On Atherosclerosis

Defects in the E3 ubiquitin ligase Parkin are sine qua non of Parkinson and related neurodegenerative diseases. Loss of ubiquitination of distinct targets leads to accumulation of cytotoxic protein aggregates, loss of mitophagy, and defects in lipid metabolism. Given the critical role of these processes in plaque macrophages, we set out to define the role of Parkin in atherosclerosis. Pro-atherogenic LDLR-KO mice were transplanted with bone marrow (BM) from wild type and Parkin-KO mice and lesion formation stimulated by 4 months of Western diet feeding. Mice transplanted with wild type BM developed lipid-rich atherosclerotic plaques in both the aortic root and whole aorta replete with foam cell macrophages. In contrast, mice transplanted with Parkin-deficient BM had significantly reduced plaque burden with concomitant reductions in lipid content, foam cell macrophages, and surrogates of plaque complexity including reduced lesional apoptosis and necrotic core formation. The paradoxical atherogenic role for Parkin including development of lipid-laden foam cell macrophages led us to focus on the impact of Parkin in macrophage lipid handling. We find that Parkin mediates the ubiquitination and stabilization of scavenger receptor CD36, a key lipid transporter in macrophages. Parkin-null macrophages had reduced expression of CD36 and concomitant reductions in oxLDL uptake. Further, Parkin deficiency decreased cholesterol efflux in macrophages exacerbating macrophage lipid storage. These results suggest that the non-canonical functions of Parkin in lipid metabolism outweigh its traditional cytoprotective roles in macrophages and mediate its deleterious effects on atherosclerotic progression.

Effects of subchronic dietary exposure to the engineered nanomaterials SiO2 and CeO2 in C57BL/6J and 5xFAD Alzheimer model mice

BackgroundThere is an increasing concern about the neurotoxicity of engineered nanomaterials (NMs). To investigate the effects of subchronic oral exposures to SiO2 and CeO2 NMs on Alzheimer’s disease (AD)-like pathology, 5xFAD transgenic mice and their C57BL/6J littermates were fed ad libitum for 3 or 14 weeks with control food pellets, or pellets dosed with these respective NMs at 0.1% or 1% (w/w). Behaviour effects were evaluated by X-maze, string suspension, balance beam and open field tests. Brains were analysed for plaque load, beta-amyloid peptide levels, markers of oxidative stress and neuroinflammation.ResultsNo marked behavioural impairments were observed in the mice exposed to SiO2 or CeO2 and neither treatment resulted in accelerated plaque formation, increased oxidative stress or inflammation. In contrast, the 5xFAD mice exposed to 1% CeO2 for 14 weeks showed significantly lower hippocampal Aβ plaque load and improved locomotor activity compared to the corresponding controls.ConclusionsThe findings from the present study suggest that long-term oral exposure to SiO2 or CeO2 NMs has no neurotoxic and AD-promoting effects. The reduced plaque burden observed in the mice following dietary CeO2 exposure warrants further investigation to establish the underlying mechanism, given the easy applicability of this administration method.

The niacin receptor HCAR2 modulates microglial response and limits disease progression in a mouse model of Alzheimer's disease.

Increased dietary intake of niacin has been correlated with reduced risk of Alzheimer's disease (AD). Niacin serves as a high-affinity ligand for the receptor HCAR2 (GPR109A). In the brain, HCAR2 is expressed selectively by microglia and is robustly induced by amyloid pathology in AD. The genetic inactivation of Hcar2 in 5xFAD mice, a model of AD, results in impairment of the microglial response to amyloid deposition, including deficits in gene expression, proliferation, envelopment of amyloid plaques, and uptake of amyloid-β (Aβ), ultimately leading to exacerbation of amyloid burden, neuronal loss, and cognitive deficits. In contrast, activation of HCAR2 with an FDA-approved formulation of niacin (Niaspan) in 5xFAD mice leads to reduced plaque burden and neuronal dystrophy, attenuation of neuronal loss, and rescue of working memory deficits. These data provide direct evidence that HCAR2 is required for an efficient and neuroprotective response of microglia to amyloid pathology. Administration of Niaspan potentiates the HCAR2-mediated microglial protective response and consequently attenuates amyloid-induced pathology, suggesting that its use may be a promising therapeutic approach to AD that specifically targets the neuroimmune response.

Repeated Home-Applied Dual-Light Antibacterial Photodynamic Therapy Can Reduce Plaque Burden, Inflammation, and aMMP-8 in Peri-Implant Disease-A Pilot Study.

Until now, in clinical dentistry, antibacterial photodynamic therapy (aPDT) has been restricted to in-office treatments, which hampers repeated applications. This pilot study tested the benefit of a commercially available Lumoral® device designed for regular periodontal dual-light aPDT treatment at home. Seven patients with peri-implant disease applied dual-light aPDT daily in addition to their normal dental hygiene for four weeks. A single Lumoral® treatment includes an indocyanine green mouth rinse followed by 40 J/cm2 radiant exposure to a combination of 810 nm and 405 nm light. A point-of-care analysis of active-matrix metalloproteinase (aMMP-8), visible plaque index (VPI), bleeding on probing (BOP), and peri-implant pocket depth (PPD) measurements was performed on day 0, day 15, and day 30. Reductions in aMMP-8 (p = 0.047), VPI (p = 0.03), and BOP (p = 0.03) were observed, and PPD was measured as being 1 mm lower in the implant (p = ns). These results suggest a benefit of regular application of dual-light aPDT in peri-implantitis. Frequently repeated application can be a promising approach to diminishing the microbial burden and to lowering the tissue destructive proteolytic and inflammatory load around dental implants. Further studies in larger populations are warranted to show the long-term benefits.

Toward Bridging Unmet Medical Need in Early Alzheimer's Disease: An Evaluation of Beta-Amyloid (Aβ) Plaque Burden as a Potential Drug Development Tool.

Toward Bridging Unmet Medical Need in Early Alzheimer's Disease: An Evaluation of Beta-Amyloid (Aβ) Plaque Burden as a Potential Drug Development Tool.

Gas6 induces inflammation and reduces plaque burden but worsens behavior in a sex-dependent manner in the APP/PS1 model of Alzheimer\u2019s disease

BackgroundAlzheimer’s disease is the leading cause of dementia worldwide. TAM receptor tyrosine kinases (Tyro3, Axl, MerTK) are known for their role in engagement of phagocytosis and modulation of inflammation, and recent evidence suggests a complex relationship between Axl, Mer, and microglial phagocytosis of amyloid plaques in AD. Gas6, the primary CNS TAM ligand, reduces neuroinflammation and improves outcomes in murine models of CNS disease. Therefore, we hypothesized that AAV-mediated overexpression of Gas6 would alleviate plaque pathology, reduce neuroinflammation, and improve behavior in the APP/PS1 model of Alzheimer’s disease.MethodsAdeno-associated viral vectors were used to overexpress Gas6 in the APP/PS1 model of Alzheimer’s disease. Nine-month-old male and female APP/PS1 and nontransgenic littermates received bilateral stereotactic hippocampal injections of AAV-Gas6 or AAV-control, which expresses a non-functional Gas6 protein. One month after injections, mice underwent a battery of behavioral tasks to assess cognitive function and brains were processed for immunohistochemical and transcriptional analyses.ResultsGas6 overexpression reduced plaque burden in male APP/PS1 mice. However, contrary to our hypothesis, Gas6 increased pro-inflammatory microglial gene expression and worsened contextual fear conditioning compared to control-treated mice. Gas6 overexpression appeared to have no effect on phagocytic mechanisms in vitro or in vivo as measured by CD68 immunohistochemistry, microglial methoxy-04 uptake, and primary microglial uptake of fluorescent fibrillar amyloid beta.ConclusionOur data describes a triad of worsened behavior, reduced plaque number, and an increase in proinflammatory signaling in a sex-specific manner. While Gas6 has historically induced anti-inflammatory signatures in the peripheral nervous system, our data suggest an alternative, proinflammatory role in the context of Alzheimer’s disease pathology.

Transcoronary stem cell transfer and evolution of infarct-related artery atherosclerosis: evaluation with conventional and novel imaging techniques including Quantitative Virtual Histology (qVH).

It has been suggested that infarct-related artery (IRA) atherosclerosis progression after stem cell transcoronary administration might represent a stem-cell mediated adverse effect. To evaluate, using conventional (quantitative coronary angiography, QCA, intravascular ultrasound - IVUS) and novel (quantitative virtual histology - qVH) tools, evolution of IRA atherosclerosis following transcoronary stem cell transfer. QCA, IVUS, VH-IVUS and qVH were performed in 22 consecutive patients (4 women) aged 59 years (data provided as median) undergoing a distal-to-stent infusion of 2.21 × 106 CD34+CXCR4+ autologous bone marrow cells via a cell delivery-dedicated perfusion catheter at anterior AMI day 7. Imaging was repeated at 12 months. This was a substudy of Myocardial Regeneration by Intracoronary Infusion of Selected Population of Stem Cells in Acute Myocardial Infarction (REGENT) Trial (NCT00316381). 18.2% subjects showed absence of distal-to-stent angiographic/IVUS atherosclerotic lesion(s) at baseline and no new lesion(s) at 12-months. In the remaining cohort, there were 28 lesions by QCA (32 by IVUS) at baseline and no new lesion(s) at follow-up. Three fibroatheromas evolved (2 to calcified fibroatheroma and 1 to a fibrocalcific lesion); other plaques maintained their stable (low-risk) phenotypes. Diameter stenosis of QCA-identified lesions was 29.5 vs. 26.5% (p = 0.012, baseline vs. 12-months). Gray-scale IVUS showed reduction in area stenosis (33.8 vs. 31.0%, p = 0.004) and plaque burden (66.27 vs. 64.56%, p = 0.009) at 12-months. Peak fibrotic plaque content increased from 70.41% to 75.0% (p = 0.004). qVH peak confluent necrotic core area and minimal fibrous cap thickness remained stable (0.64 vs. 0.59 mm2, p = 0.290, and 0.15 vs. 0.16 mm, p = 0.646). This study, using a range of classic and novel imaging techniques, indicates lack of any stimulatory effect of transcoronary stem cell transfer on coronary atherosclerosis. Whether, and to what extent, a moderate reduction in plaque burden and stenosis severity at 12-months results from optimized pharmacotherapy and/or stem cell transfer requires further elucidation.

Abstract 13914: Low-Density Lipoprotein Delivery of Microbial Small RNAs Drives Atherosclerosis Through Macrophage Toll-Like Receptor 8

Low-density lipoproteins (LDL) are a causal factor for atherosclerosis, a key pathological process in cardiovascular disease. Within atherosclerotic lesions, macrophages present a spectrum of phenotypes that mediate both disease pathogenesis and resolution. Inflammatory macrophage phenotypes are pro-atherogenic, but the natural factors that promote polarization remain to be identified. Here, we demonstrate that microbial small RNAs (msRNA) are enriched on LDL and drive pro-inflammatory macrophage polarization and cytokine secretion via activation of toll-like receptor 8 (TLR8). Removal of msRNA cargo during LDL reconstitution yields particles that are taken up by macrophages but fail to stimulate inflammatory activation. Using loss-of-function and gain-of-function studies, we demonstrate that TLR8 is both necessary and sufficient for LDL-induced activation of NF-kappa-B, a central regulator of inflammatory macrophage polarization. TLR8 recognition of msRNA was found to be antagonized by non-targeting locked-nucleic acids (nt-LNA). Pre-treatment of macrophages with a nt-LNA was found to prevent LDL-induced macrophage polarization in vitro , and re-organize lesion macrophage phenotypes in vivo , as determined by single-cell RNA sequencing. Critically, we demonstrate that nt-LNA treatment reduced plaque burden in 4-week and 10-week atherosclerosis progression studies in Apoe -/- mice fed a western diet. Moreover, in a regression model using male and female Ldlr -/- mice with advanced lesions, nt-LNA treatment in combination with dietary intervention promoted lesion regression relative to mice receiving only dietary intervention. These results identify LDL-msRNA as stimuli for atherosclerosis-associated inflammation and support alternative functions of LDL beyond cholesterol transport.

In This Issue

HomeCirculation ResearchVol. 129, No. 4In This Issue Free AccessIn BriefPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyRedditDiggEmail Jump toFree AccessIn BriefPDF/EPUBIn This Issue Ruth Williams Ruth WilliamsRuth Williams Search for more papers by this author Originally published5 Aug 2021https://doi.org/10.1161/RES.0000000000000497Circulation Research. 2021;129:455is related toUnveiling Complexity and Multipotentiality of Early Heart Fieldsis related toCoronary Disease Association With ADAMTS7 Is Due to Protease ActivityDisrupted Resolution Mechanisms Favor Altered Phagocyte Responses in COVID-19Disrupted Resolution Mechanisms Favor Altered Phagocyte Responses in COVID-19 (p e54)Download figureDownload PowerPointKoenis et al show that dysregulation of inflammation-resolving factors is a feature of severe COVID-19.Inflammation is essential in the early stages of battling an invading pathogen, but can become damaging to the host if not resolved in a timely manner. Indeed, prolonged and unresolved inflammation is responsible for the hospitalizations and deaths of many COVID-19 patients. An excess of circulating pro-inflammatory cytokines is one feature of severe COVID-19, and now Koenis and colleagues show that certain pro-resolving factors are out of balance in such patients too. While blood samples from patients with mild COVID-19 revealed an increase in specialized pro-resolving lipid mediators (SPMs), those from patients with severe disease had lower levels of these lipid factors. Expression of SPM receptors on phagocytes was also higher in patients with mild disease than those with severe COVID-19. And, in line with this, the proportion of activated pro-inflammtory phagocytes was higher in patients with severe disease. The team went on to show that patients treated with the steroid dexamethasone had increased blood levels of SPMs. Together the results reveal SPMs are dysregulated in severe cases of COVID-19 and suggest SPM modulation, whether via steroid administration or other pharmacological means, could promote resolution of out-of-control inflammation.Coronary Disease Association with ADAMTS7 Is due to Protease Activity (p 458)Download figureDownload PowerPointCatalytic function of ADAMTS7 is needed for the enzyme’s pro-atherogenic activity, say Mizoguchi et al.Several genome-wide association studies (GWAS) have identified variants at the ADAMTS7 gene and its surrounding intergenic regions as risk loci for coronary artery disease. Furthermore, animal studies suggest the ADAMTS7 protein, which is both a metalloproteinase enzyme and a proteoglycan, is pro-atherogenic. However, which of the protein’s identities is responsible for promoting atherosclerosis is unclear. Mizoguchi and colleagues now show that the enzymatic function of ADAMTS7 is to blame. The team generated mice with [a] catalytically inactive version of ADAMTS7 and compared these animals with ones that either lacked ADAMTS7 entirely or had the fully intact protein (wild type). They found that loss of either ADAMTS7 protein itself or just its catalytic function was enough to reduce plaque burden in two different models of atherosclerosis. ADAMTS7 is known to regulate migration of vascular smooth muscle cells (VSMCs), which contributes to plaque formation, and VSMCs lacking either the full protein or just its catalytic activity had impaired migratory activity, the team showed. Together the results pinpoint ADAMTS7’s enzyme activity as pro-atherogenic and suggest the catalytic domain of the protein could be a therapeutic target for curtailing atherosclerosis.Unveiling Complexity and Multipotentiality of Early Heart Fields (p 474)Download figureDownload PowerPointZhang et al discover a shared source of mesodermal progenitors contributing to both the heart and extraembryonic tissues.The developing heart is thought to originate from two populations of cells—the first and second heart fields—which are first identifiable in the stage E7.5 mouse embryo (day 15 human embryo). Genes controlling the development of these fields have been linked to congenital heart defects (CHDs), but interestingly CHDs are also sometimes linked to placental abnormalities for reasons that are unclear. Zhang and colleagues now show that the first heart field and extraembryonic tissues—those which gives rise to the yolk sac and placenta—have an unexpected link. Through lineage-tracing experiments and single-cell transcriptomics, the team discovered that the first heart field consists of two sources of mesoderm progenitors—one that is embryonic in nature, and the other that arises from the interface between extraembryonic and embryonic tissues of the early gastrula. This latter population of progenitors, which expresses the transcription factor Hand1, gives rise to extraembryonic mesoderm cells in addition to heart field cells, the team showed. The finding of this shared source of mesodermal progenitors not only blurs the lines between the embryo and its supporting tissues, but may also explain the link between placental abnormalities and CHDs. Previous Back to top Next FiguresReferencesRelatedDetailsRelated articlesUnveiling Complexity and Multipotentiality of Early Heart FieldsQingquan Zhang, et al. Circulation Research. 2021;129:474-487Coronary Disease Association With ADAMTS7 Is Due to Protease ActivityTaiji Mizoguchi, et al. Circulation Research. 2021;129:458-470Disrupted Resolution Mechanisms Favor Altered Phagocyte Responses in COVID-19Duco Steven Koenis, et al. Circulation Research. 2021;129:e54-e71 August 6, 2021Vol 129, Issue 4Article InformationMetrics © 2021 American Heart Association, Inc.https://doi.org/10.1161/RES.0000000000000497 Originally publishedAugust 5, 2021 PDF download Advertisement

Silencing Myeloid Netrin-1 Induces Inflammation Resolution and Plaque Regression.

Rationale: Therapeutic efforts to decrease atherosclerotic cardiovascular disease risk have focused largely on reducing atherogenic lipoproteins, yet lipid-lowering therapies alone are insufficient to fully regress plaque burden. We postulate that arterial repair requires resolution of a maladaptive immune response and that targeting factors that hinder inflammation resolution will facilitate plaque regression. Objective: The guidance molecule Ntn1 (netrin-1) is secreted by macrophages in atherosclerotic plaques, where it sustains inflammation by enhancing macrophage survival and blocking macrophage emigration. We tested whether silencing Ntn1 in advanced atherosclerosis could resolve arterial inflammation and regress plaques. Methods and Results: To temporally silence Ntn1 in myeloid cells, we generated genetically modified mice in which Ntn1 could be selectively deleted in monocytes and macrophages using a tamoxifen-induced CX3CR1-driven cre recombinase (Ntn1fl/flCx3cr1creERT2+) and littermate control mice (Ntn1fl/flCx3cr1WT). Mice were fed Western diet in the setting of hepatic PCSK9 (proprotein convertase subtilisin/kexin type 9) overexpression to render them atherosclerotic and then treated with tamoxifen to initiate deletion of myeloid Ntn1 (MøΔNtn1) or not in controls (MøWT). Morphometric analyses performed 4 weeks later showed that myeloid Ntn1 silencing reduced plaque burden in the aorta (−50%) and plaque complexity in the aortic root. Monocyte-macrophage tracing experiments revealed lower monocyte recruitment, macrophage retention, and proliferation in MøΔNtn1 compared with MøWT plaques, indicating a restructuring of monocyte-macrophage dynamics in the artery wall upon Ntn1 silencing. Single-cell RNA sequencing of aortic immune cells before and after Ntn1 silencing revealed upregulation of gene pathways involved in macrophage phagocytosis and migration, including the Ccr7 chemokine receptor signaling pathway required for macrophage emigration from plaques and atherosclerosis regression. Additionally, plaques from MøΔNtn1 mice showed hallmarks of inflammation resolution, including higher levels of proresolving macrophages, IL (interleukin)-10, and efferocytosis, as compared to plaques from MøWT mice. Conclusion: Our data show that targeting Ntn1 in advanced atherosclerosis ameliorates atherosclerotic inflammation and promotes plaque regression.

The Lab4P Consortium of Probiotics Attenuates Atherosclerosis in LDL Receptor Deficient Mice Fed a High Fat Diet and Causes Plaque Stabilization by Inhibiting Inflammation and Several Pro-Atherogenic Processes.

ScopePrevious studies show that Lab4 probiotic consortium plus Lactobacillus plantarum CUL66 (Lab4P) reduces diet‐induced weight gain and plasma cholesterol levels in C57BL/6J mice fed a high fat diet (HFD). The effect of Lab4P on atherosclerosis is not known and is therefore investigated.Methods and ResultsAtherosclerosis‐associated parameters are analyzed in LDL receptor deficient mice fed HFD for 12 weeks alone or supplemented with Lab4P. Lab4P increases plasma HDL and triglyceride levels and decreases LDL/VLDL levels. Lab4P also reduces plaque burden and content of lipids and macrophages, indicative of dampened inflammation, and increases smooth muscle cell content, a marker of plaque stabilization. Atherosclerosis arrays show that Lab4P alters the liver expression of 19 key disease‐associated genes. Lab4P also decreases the frequency of macrophages and T‐cells in the bone marrow. In vitro assays using conditioned media from probiotic bacteria demonstrates attenuation of several atherosclerosis‐associated processes in vitro such as chemokine‐driven monocytic migration, proliferation of monocytes and macrophages, foam cell formation and associated changes in expression of key genes, and proliferation and migration of vascular smooth muscle cells.ConclusionThis study provides new insights into the anti‐atherogenic actions of Lab4P together with the underlying mechanisms and supports further assessments in human trials.

Therapeutic potential of astaxanthin and superoxide dismutase in Alzheimer's disease.

Oxidative stress, the imbalance of the antioxidant system, results in an accumulation of neurotoxic proteins in Alzheimer's disease (AD). The antioxidant system is composed of exogenous and endogenous antioxidants to maintain homeostasis. Superoxide dismutase (SOD) is an endogenous enzymatic antioxidant that converts superoxide ions to hydrogen peroxide in cells. SOD supplementation in mice prevented cognitive decline in stress-induced cells by reducing lipid peroxidation and maintaining neurogenesis in the hippocampus. Furthermore, SOD decreased expression of BACE1 while reducing plaque burden in the brain. Additionally, Astaxanthin (AST), a potent exogenous carotenoid, scavenges superoxide anion radicals. Mice treated with AST showed slower memory decline and decreased depositions of amyloid-beta (Aβ) and tau protein. Currently, the neuroprotective potential of these supplements has only been examined separately in studies. However, a single antioxidant cannot sufficiently resist oxidative damage to the brain, therefore, a combinatory approach is proposed as a relevant therapy for ameliorating pathological changes in AD.

A Biased Relaxin Receptor Agonist, ML290, Attenuates Atherosclerotic Calcification in Apolipoprotein E‐deficient Mice

Vascular calcification is the most significant predictor of cardiovascular morbidity and mortality, but therapeutic options are unavailable. Relaxin has emerged as a vasoprotective molecule, but several drawbacks prevent therapeutic translation. Targeting the relaxin receptor, RXFP1, is safe and well-tolerated in animal models of vascular disease and humans. We identified a non-peptide biased allosteric agonist of human RXFP1, ML290, and aimed to test the hypothesis that ML290 arrests the progression of vascular calcification in a mouse model of atherosclerosis. Atherosclerotic calcification was induced in male humanized (hRXFP1/hRXFP1) mice crossbred with the ApoE-/- mice (humanized ApoE-/-) using a custom diet that contains 42% calorie fat for 25 weeks starting at 10 weeks of age. Age-matched humanized ApoE-/- mice on normal chow diet were used as negative control and received vehicle treatment starting at 10 weeks of age. Atherogenic mice were randomly assigned to either receive vehicle or ML290 (30 mg/kg) at the beginning (preventative treatment) or following 15 weeks of the atherogenic diet (reversal treatment). Vehicle and ML290 treatments were administered on alternate days via oral gavage. ML290 treatment significantly prevented (P = 0.0422, n = 8) and reversed (P = 0.0099, n = 10) atherosclerotic calcification in the aorta of humanized ApoE-/- mice fed an atherogenic diet. Longitudinal tracing of mineral formation in the aortic arch revealed accelerated mineral growth in vehicle-treated mice, and this was reduced by ML290 treatment. The anti-calcification effects of ML290 were associated with a significant (P = 0.0411, n = 5) reduction in plaque burden, but not serum cholesterol level. In vitro, ML290 reduced (P = 0.0005, n = 3) superoxide production under osteogenic conditions in vascular smooth muscle cells (VSMCs). Osteogenic changes in VSMC phenotype associate with a release of alkaline phosphatase (ALP) in extracellular vesicles (EVs), which promote mineralization. ML290 treatment significantly (P = 0.0001, n = 3) suppressed the formation of ALP-loaded EVs. BMP4, an inducer of osteogenic transition, and caveolin-1, a scaffolding protein required for calcifying EV formation, were significantly (P = 0.0059, n = 4) downregulated after 24 h treatment with ML290 compared to vehicle-treated VSMCs under osteogenic conditions. In summary, we demonstrate the therapeutic potential for ML290 to mitigate and reverse atherosclerosis-induced vascular calcification in vivo. The actions of ML290 to attenuate calcification are in part attributed to its ability to limit the release of calcifying EVs as a result of osteogenic differentiation, and to reduce vascular superoxide production. The outcomes of this study can lead to the discovery of clinically-viable non-peptide-based therapies for the treatment of vascular calcification that can benefit the rapidly increasing patient population.

MiR-33 Silencing Reprograms the Immune Cell Landscape in Atherosclerotic Plaques.

[Figure: see text].

Lanabecestat: Neuroimaging results in early symptomatic Alzheimer's disease.

IntroductionLanabecestat, a beta‐site amyloid precursor protein‐cleaving enzyme 1 (BACE1) inhibitor, was investigated as a potential Alzheimer's disease (AD)‐modifying treatment. As previously reported, amyloid beta (Aβ) neuritic plaque burden reduction did not result in clinical benefit. Lanabecestat's effects on neuroimaging biomarkers and correlations between neuroimaging biomarkers and efficacy measures are reported.MethodsAMARANTH and DAYBREAK‐ALZ were 104‐ and 78‐week, multicenter, randomized, double‐blind, placebo‐controlled studies of lanabecestat in early symptomatic AD (AMARANTH) and mild AD dementia (DAYBREAK‐ALZ). Patients randomly (1:1:1) received placebo, lanabecestat 20 mg, or lanabecestat 50 mg daily (AMARANTH, n = 2218; DAYBREAK‐ALZ, n = 1722). Florbetapir positron emission tomography (PET), fluorodeoxyglucose (FDG) PET, flortaucipir PET, and volumetric magnetic resonance imaging (MRI) were used to measure Aβ neuritic plaque burden, cerebral metabolism, aggregated tau neurofibrillary tangles, and brain volume, respectively. Additionally, florbetapir perfusion scans were performed in DAYBREAK‐ALZ. Efficacy measures included 13‐item Alzheimer's Disease Assessment Scale–Cognitive Subscale, Alzheimer's Disease Cooperative Study Activities of Daily Living Inventory, Clinical Dementia Rating–Sum of Boxes, Functional Activities Questionnaire, and Mini‐Mental State Examination. These studies stopped early due to futility.ResultsDespite previously observed annualized reduction in Aβ neuritic plaque burden, there were no treatment differences in annualized change of aggregated tau neurofibrillary tangle burden (AMARANTH, n = 284; DAYBREAK‐ALZ, n = 70), cerebral metabolism (AMARANTH, n = 260; DAYBREAK‐ALZ, n = 38) and perfusion (DAYBREAK‐ALZ, n = 213). Greater brain volume reduction (AMARANTH, n = 1697 [whole brain]; DAYBREAK‐ALZ, n = 650 [whole brain]) occurred on lanabecestat compared to placebo. Higher baseline aggregated tau neurofibrillary tangle burden, lower cerebral metabolism, and lower brain volumes correlated with poorer baseline efficacy scores and greater clinical worsening. Lower baseline cerebral perfusion correlated with poorer baseline efficacy scores. Reduction in cerebral metabolism or whole brain volume correlated with clinical worsening, regardless of treatment assignment.DiscussionTau pathology and cerebral metabolism assessments showed no evidence of lanabecestat slowing pathophysiologic progression of AD. Lanabecestat exposure was associated with brain volume reductions. Correlations between imaging measures and cognitive assessments may aid future study design.