Search

The risk of early recurrent events after stroke remains high despite currently established secondary prevention strategies 1 . Risk is particularly high in patients with atherosclerosis, with more than 10% of patients experiencing early recurrent events 1,2 . However, despite the enormous medical burden of this clinical phenomenon, the underlying mechanisms leading to increased vascular risk and recurrent stroke are largely unknown. Here, using a novel mouse model of stroke-induced recurrent ischaemia, we show that stroke leads to activation of the AIM2 inflammasome in vulnerable atherosclerotic plaques via an increase of circulating cell-free DNA. Enhanced plaque inflammation post-stroke results in plaque destabilization and atherothrombosis, finally leading to arterioarterial embolism and recurrent stroke within days after the index stroke. We confirm key steps of plaque destabilization also after experimental myocardial infarction and in carotid artery plaque samples from patients with acute stroke. Rapid neutrophil NETosis was identified as the main source of cell-free DNA after stroke and NET-DNA as the causative agent leading to AIM2 inflammasome activation. Neutralization of cell-free DNA by DNase treatment or inhibition of inflammasome activation reduced the rate of stroke recurrence after experimental stroke. Our findings present an explanation for the high recurrence rate after incident ischaemic events in patients with atherosclerosis. The detailed mechanisms uncovered here provide clinically uncharted therapeutic targets for which we show high efficacy to prevent recurrent events. Targeting DNA-mediated inflammasome activation after remote tissue injury represents a promising avenue for further clinical development in the prevention of early recurrent events., (© 2024. The Author(s).)

Background: The ADAMTS7 locus was genome-wide significantly associated with coronary artery disease. Lack of the ECM (extracellular matrix) protease ADAMTS-7 (A disintegrin and metalloproteinase-7) was shown to reduce atherosclerotic plaque formation. Here, we sought to identify molecular mechanisms and downstream targets of ADAMTS-7 mediating the risk of atherosclerosis., Methods: Targets of ADAMTS-7 were identified by high-resolution mass spectrometry of atherosclerotic plaques from Apoe -/- and Apoe -/- Adamts7 -/- mice. ECM proteins were identified using solubility profiling. Putative targets were validated using immunofluorescence, in vitro degradation assays, coimmunoprecipitation, and Förster resonance energy transfer-based protein-protein interaction assays. ADAMTS7 expression was measured in fibrous caps of human carotid artery plaques., Results: In humans, ADAMTS7 expression was higher in caps of unstable as compared to stable carotid plaques. Compared to Apoe -/- mice, atherosclerotic aortas of Apoe -/- mice lacking Adamts-7 (Apoe -/- Adamts7 -/- ) contained higher protein levels of Timp-1 (tissue inhibitor of metalloprotease-1). In coimmunoprecipitation experiments, the catalytic domain of ADAMTS-7 bound to TIMP-1, which was degraded in the presence of ADAMTS-7 in vitro. ADAMTS-7 reduced the inhibitory capacity of TIMP-1 at its canonical target MMP-9 (matrix metalloprotease-9). As a downstream mechanism, we investigated collagen content in plaques of Apoe -/- and Apoe -/- Adamts7 -/- mice after a Western diet. Picrosirius red staining of the aortic root revealed less collagen as a readout of higher MMP-9 activity in Apoe -/- as compared to Apoe -/- Adamts7 -/- mice. To facilitate high-throughput screening for ADAMTS-7 inhibitors with the aim of decreasing TIMP-1 degradation, we designed a Förster resonance energy transfer-based assay targeting the ADAMTS-7 catalytic site., Conclusions: ADAMTS-7, which is induced in unstable atherosclerotic plaques, decreases TIMP-1 stability reducing its inhibitory effect on MMP-9, which is known to promote collagen degradation and is likewise associated with coronary artery disease. Disrupting the interaction of ADAMTS-7 and TIMP-1 might be a strategy to increase collagen content and plaque stability for the reduction of atherosclerosis-related events., Competing Interests: Disclosures Dr Schunkert has received personal fees from MSD SHARP & DOHME, AMGEN, Bayer Vital GmbH, Boehringer Ingelheim, Daiichi-Sankyo, Novartis, Servier, Brahms, Bristol-Myers-Squibb, Medtronic, Sanofi Aventis, Synlab, Pfizer, and Vifor T as well as grants and personal fees from Astra-Zeneca outside the submitted work. Drs Schunkert and Kessler are named inventors on a patent application for prevention of restenosis after angioplasty and stent implantation outside the submitted work. Dr Kessler received lecture fees from Bayer, Bristol-Myers Squibb, Abbott, and Astra-Zeneca, which are unrelated to this work. Dr Bernhagen is an inventor on patents related to anti-MIF and antichemokine strategies in inflammation and CVD (cardiovascular diseases) outside the submitted work. The other authors report no conflicts.

Physical exercise represents an effective preventive and therapeutic strategy beneficially modifying the course of multiple diseases. The protective mechanisms of exercise are manifold; primarily, they are elicited by alterations in metabolic and inflammatory pathways. Exercise intensity and duration strongly influence the provoked response. This narrative review aims to provide comprehensive up-to-date insights into the beneficial effects of physical exercise by illustrating the impact of moderate and vigorous exercise on innate and adaptive immunity. Specifically, we describe qualitative and quantitative changes in different leukocyte subsets while distinguishing between acute and chronic exercise effects. Further, we elaborate on how exercise modifies the progression of atherosclerosis, the leading cause of death worldwide, representing a prime example of a disease triggered by metabolic and inflammatory pathways. Here, we describe how exercise counteracts causal contributors and thereby improves outcomes. In addition, we identify gaps that still need to be addressed in the future.

Aims: Targeting vascular inflammation represents a novel therapeutic approach to reduce complications of atherosclerosis. Neutralizing the pro-inflammatory cytokine interleukin-1β (IL-1β) using canakinumab, a monoclonal antibody, reduces the incidence of cardiovascular events in patients after myocardial infarction (MI). The biological basis for these beneficial effects remains incompletely understood. We sought to explore the mechanisms of IL-1β-targeted therapies., Methods and Results: In mice with early atherosclerosis (ApoE-/- mice on a high-cholesterol diet for 6 weeks), we found that 3 weeks of NACHT, LRR, and PYD domains-containing protein 3 (NLRP3)-inflammasome inhibition or anti-IL-1β treatment (using either MCC950, an NLRP3-inflammasome inhibitor which blocks production and release of active IL-1β, or a murine analogue of canakinumab) dampened accumulation of leucocytes in atherosclerotic aortas, which consequently resulted in slower progression of atherosclerosis. Causally, we found that endothelial cells from atherosclerotic aortas lowered expression of leucocyte chemoattractants and adhesion molecules upon NLRP3-inflammasome inhibition, indicating that NLRP3-inflammasome- and IL-1β-targeted therapies reduced blood leucocyte recruitment to atherosclerotic aortas. In accord, adoptive transfer experiments revealed that anti-IL-1β treatment mitigated blood myeloid cell uptake to atherosclerotic aortas. We further report that anti-IL-1β treatment and NLRP3-inflammasome inhibition reduced inflammatory leucocyte supply by decreasing proliferation of bone marrow haematopoietic stem and progenitor cells, demonstrating that suppression of IL-1β and the NLRP3-inflammasome lowered production of disease-propagating leucocytes. Using bone marrow reconstitution experiments, we observed that haematopoietic cell-specific NLRP3-inflammasome activity contributed to both enhanced recruitment and increased supply of blood inflammatory leucocytes. Further experiments that queried whether anti-IL-1β treatment reduced vascular inflammation also in post-MI accelerated atherosclerosis documented the operation of convergent mechanisms (reduced supply and uptake of inflammatory leucocytes). In line with our pre-clinical findings, post-MI patients on canakinumab treatment showed reduced blood monocyte numbers., Conclusions: Our murine and human data reveal that anti-IL-1β treatment and NLRP3-inflammasome inhibition dampened vascular inflammation and progression of atherosclerosis through reduced blood inflammatory leucocyte (i) supply and (ii) uptake into atherosclerotic aortas providing additional mechanistic insights into links between haematopoiesis and atherogenesis, and into the beneficial effects of NLRP3-inflammasome- and IL-1β-targeted therapies., Competing Interests: Conflict of interest: H.G. is a full time Novartis employee. H.S. reports personal fees from MSD Sharp & Dohme, AMGEN, Bayer Vital GmbH, Boehringer Ingelheim, Daiichi-Sankyo, Novartis, Servier, Brahms, Bristol-Myers Squibb, Medtronic, Sanofi Aventis, Synlab, Pfizer, grants and personal fees from Astra-Zeneca, and personal fees from Vifor outside the submitted work. H.S. and T.K. are named inventors on a patent application for prevention of restenosis after angioplasty and stent implantation outside the submitted work. T.K. received lecture fees from Bayer AG, Pharmaceuticals. H.B.S. reports grants from the European Research Council, the ‘Else-Kröner-Fresenius-Stiftung’, the ‘Deutsche Herzstiftung’, and the ‘Deutsche Forschungsgemeinschaft’ during the conduct of the study. A.A.B.R. is inventor on several licensed patents on novel NLRP3 inhibitors. P.L. is an unpaid consultant to, or involved in, clinical trials for Amgen, AstraZeneca, Esperion Therapeutics, Ionis Pharmaceuticals, Kowa Pharmaceuticals, Novartis, Pfizer, Sanofi-Regeneron, and XBiotech, Inc. He is a member of the scientific advisory boards for Amgen, Corvidia Therapeutics, DalCor Pharmaceuticals, IFM Therapeutics, Kowa Pharmaceuticals, Olatec Therapeutics, Medimmune, Novartis, and XBiotech, Inc and also serves on the Board of XBiotech, Inc. P.L.’s laboratory has received research funding in the last 2 years from Novartis, and he has a financial interest in Xbiotech, a company developing therapeutic human antibodies. P.L.’s interests were reviewed and are managed by Brigham and Women’s Hospital and Partners HealthCare, Boston, USA, in accordance with their conflict of interest policies. W.K. reports personal fees from AstraZeneca, Novartis, Pfizer, The Medicines Company, DalCor, Kowa, Amgen, Corvidia, Daiichi-Sankyo, Berlin-Chemie, Sanofi, Bristol-Myers Squibb, and grants and non-financial support from Singulex, Abbott, Roche Diagnostics, and Beckmann, all outside the submitted work. P.R. has received research grant support from Novartis, Kowa, Amarin, Pfizer, and the NHLBI; and has served as a consultant to Corvidia, Novartis, Flame, Agepha, Inflazome, AstraZeneca, Janssen, Civi Biopharm, SOCAR, Novo Nordisk, Uptton, Omeicos, Health Outlook, and Boehringer-Ingelheim. All other authors have nothing to disclose., (© The Author(s) 2021. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: Inflammation strongly contributes to atherosclerosis initiation and progression. Consequently, recent clinical trials pharmacologically targeted vascular inflammation to decrease the incidence of atherosclerosis-related complications. Colchicine, a microtubule inhibitor with anti-inflammatory properties, reduced cardiovascular events in patients with recent acute coronary syndrome and chronic coronary disease. However, the biological basis of these observations remains elusive. We sought to explore the mechanism by which colchicine beneficially alters the course of atherosclerosis., Methods and Results: In mice with early atherosclerosis ( Apoe -/- mice on a high cholesterol diet for 8 weeks), we found that colchicine treatment (0.25 mg/kg bodyweight once daily over four weeks) reduced numbers of neutrophils, inflammatory monocytes and macrophages inside atherosclerotic aortas using flow cytometry and immunohistochemistry. Consequently, colchicine treatment resulted in a less inflammatory plaque composition and reduced plaque size. We next investigated how colchicine prevented plaque leukocyte expansion and found that colchicine treatment mitigated recruitment of blood neutrophils and inflammatory monocytes to plaques as revealed by adoptive transfer experiments. Causally, we found that colchicine reduced levels of both leukocyte adhesion molecules and receptors for leukocyte chemoattractants on blood neutrophils and monocytes. Further experiments showed that colchicine treatment reduced vascular inflammation also in post-myocardial infarction accelerated atherosclerosis through similar mechanisms as documented in early atherosclerosis. When we examined whether colchicine also decreased numbers of macrophages inside atherosclerotic plaques by impacting monocyte/macrophage transitioning or in-situ proliferation of macrophages, we report that colchicine treatment did not influence macrophage precursor differentiation or macrophage proliferation using cell culture experiments with bone marrow derived macrophages., Conclusions: Our data reveal that colchicine prevents expansion of plaque inflammatory leukocytes through lowering recruitment of blood myeloid cells to plaques. These data provide novel mechanistic clues on the beneficial effects of colchicine in the treatment of atherosclerosis and may inform future anti-inflammatory interventions in patients at risk., Competing Interests: HSa reports grants from the European Research Council, the “Else-Kröner-Fresenius-Stiftung”, the “Deutsche Herzstiftung” and the “Deutsche Forschungsgemeinschaft” during the conduct of the study. HSa received lecture fees from Novo Nordisk. HSc reports personal fees from MSD Sharp & Dohme, personal fees from AMGEN, personal fees from Bayer Vital GmbH, personal fees from Boehringer Ingelheim, personal fees from Daiichi-Sankyo, personal fees from Novartis, personal fees from Servier, personal fees from Brahms, personal fees from Bristol-Myers Squibb, personal fees from Medtronic, personal fees from Sanofi Aventis, personal fees from Synlab, personal fees from Pfizer, grants and personal fees from Astra-Zeneca and personal fees from Vifor, outside the submitted work. HSc and TK are named inventors on a patent application for prevention of restenosis after angioplasty and stent implantation outside the submitted work. TK received lecture fees from Bayer AG, Pharmaceuticals. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Meyer-Lindemann, Mauersberger, Schmidt, Moggio, Hinterdobler, Li, Khangholi, Hettwer, Gräßer, Dutsch, Schunkert, Kessler and Sager.)

Significance: Atherosclerosis and its complications, such as acute coronary syndromes, are the leading causes of death worldwide. A wide range of inflammatory processes substantially contribute to the initiation and progression of cardiovascular disease (CVD). In addition, epidemiological studies strongly associate both chronic stress and acute psychosocial stress with the occurrence of CVDs. Recent Advances: Extensive research during recent decades has not only identified major pathways in cardiovascular inflammation but also revealed a link between psychosocial factors and the immune system in the context of atherosclerosis. Both chronic and acute psychosocial stress drive systemic inflammation via neuroimmune interactions and promote atherosclerosis progression. Critical Issues: The associations human epidemiological studies found between psychosocial stress and cardiovascular inflammation have been substantiated by additional experimental studies in mice and humans. However, we do not yet fully understand the mechanisms through which psychosocial stress drives cardiovascular inflammation; consequently, specific treatment, although urgently needed, is lacking. Future Directions: Psychosocial factors are increasingly acknowledged as risk factors for CVD and are currently treated via behavioral interventions. Additional mechanistic insights might provide novel pharmacological treatment options to reduce stress-related morbidity and mortality. Antioxid. Redox Signal. 35, 1531-1550.

Aims: Mental stress substantially contributes to the initiation and progression of human disease, including cardiovascular conditions. We aim to investigate the underlying mechanisms of these contributions since they remain largely unclear., Methods and Results: Here, we show in humans and mice that leucocytes deplete rapidly from the blood after a single episode of acute mental stress. Using cell-tracking experiments in animal models of acute mental stress, we found that stress exposure leads to prompt uptake of inflammatory leucocytes from the blood to distinct tissues including heart, lung, skin, and, if present, atherosclerotic plaques. Mechanistically, we found that acute stress enhances leucocyte influx into mouse atherosclerotic plaques by modulating endothelial cells. Specifically, acute stress increases adhesion molecule expression and chemokine release through locally derived norepinephrine. Either chemical or surgical disruption of norepinephrine signalling diminished stress-induced leucocyte migration into mouse atherosclerotic plaques., Conclusion: Our data show that acute mental stress rapidly amplifies inflammatory leucocyte expansion inside mouse atherosclerotic lesions and promotes plaque vulnerability., (© The Author(s) 2021. Published by Oxford University Press on behalf of the European Society of Cardiology.)

The article presents the discussion on neutrophil–lymphocyte ratio and incident atherosclerotic events. Topics include atherosclerosis being a multifactorial disease with profoundly altering lipoprotein metabolism; neutrophils belonging to the first line of innate immune defence and contributing to atherosclerosis; and neutrophils releasing neutrophil extracellular traps containing cytotoxic histone.

Exposure to psychosocial stress is a risk factor for many diseases, including atherosclerosis. Although incompletely understood, interaction between the psyche and the immune system provides one potential mechanism linking stress and disease inception and progression. Known cross-talk between the brain and immune system includes the hypothalamic-pituitary-adrenal axis, which centrally drives glucocorticoid production in the adrenal cortex, and the sympathetic-adrenal-medullary axis, which controls stress-induced catecholamine release in support of the fight-or-flight reflex. It remains unknown, however, whether chronic stress changes hematopoietic stem cell activity. Here we show that stress increases proliferation of these most primitive hematopoietic progenitors, giving rise to higher levels of disease-promoting inflammatory leukocytes. We found that chronic stress induced monocytosis and neutrophilia in humans. While investigating the source of leukocytosis in mice, we discovered that stress activates upstream hematopoietic stem cells. Under conditions of chronic variable stress in mice, sympathetic nerve fibers released surplus noradrenaline, which signaled bone marrow niche cells to decrease CXCL12 levels through the β3-adrenergic receptor. Consequently, hematopoietic stem cell proliferation was elevated, leading to an increased output of neutrophils and inflammatory monocytes. When atherosclerosis-prone Apoe−/− mice were subjected to chronic stress, accelerated hematopoiesis promoted plaque features associated with vulnerable lesions that cause myocardial infarction and stroke in humans. [ABSTRACT FROM AUTHOR]

Although the importance of inflammation in atherosclerosis is now well established, the exact molecular processes linking inflammation to the development and course of the disease are not sufficiently understood. In this context, modern genetics—as applied by genome-wide association studies (GWAS)—can serve as a comprehensive and unbiased tool for the screening of potentially involved pathways. Indeed, a considerable proportion of loci discovered by GWAS is assumed to affect inflammatory processes. Despite many well-replicated association findings, however, translating genomic hits to specific molecular mechanisms remains challenging. This review provides an overview of the currently most relevant inflammation-related GWAS findings in coronary artery disease and explores their potential clinical perspectives. [ABSTRACT FROM AUTHOR]

BACKGROUND: A chromosomal locus at 4q32.1 has been genomewide significantly associated with coronary artery disease risk. The locus encompasses GUCY1A3, which encodes the α1 subunit of the soluble guanylyl cyclase (sGC), a key enzyme in the nitric oxide/cGMP signaling pathway. The mechanism linking common variants in this region with coronary risk is not known. METHODS: Gene expression and protein expression were analyzed with quantitative polymerase chain reaction and immunoblotting, respectively. Putative allele-specific transcription factors were identified with in silico analyses and validated via allele-specific quantification of antibody-precipitated chromatin fractions. Regulatory properties of the lead risk variant region were analyzed with reporter gene assays. To assess the effect of zinc finger E box-binding homeobox 1 transcription factor (ZEB1), siRNA-mediated knockdown and overexpression experiments were performed. Association of GUCY1A3 genotype and cellular phenotypes was analyzed with vascular smooth muscle cell migration assays and platelet aggregation analyses. RESULTS: Whole-blood GUCY1A3 mRNA levels were significantly lower in individuals homozygous for the lead (rs7692387) risk variant. Likewise, reporter gene assays demonstrated significantly lower GUCY1A3 promoter activity for constructs carrying this allele. In silico analyses located a DNase I hypersensitivity site to rs7692387 and predicted binding of the transcription factor ZEB1 rather to the nonrisk allele, which was confirmed experimentally. Knockdown of ZEB1 resulted in more profound reduction of nonrisk allele promoter activity and a significant reduction of endogenous GUCY1A3 expression. Ex vivo–studied platelets from homozygous nonrisk allele carriers displayed enhanced inhibition of ADP-induced platelet aggregation by the nitric oxide donor sodium nitroprusside and the phosphodiesterase 5 inhibitor sildenafil compared with homozygous risk allele carriers. Moreover, pharmacological stimulation of sGC led to reduced migration only in vascular smooth muscle cells homozygous for the nonrisk allele. In the Hybrid Mouse Diversity Panel, higher levels of GUCY1A3 expression correlated with less atherosclerosis in the aorta. CONCLUSIONS: Rs7692387 is located in an intronic site that modulates GUCY1A3 promoter activity. The transcription factor ZEB1 binds preferentially to the nonrisk allele, leading to an increase in GUCY1A3 expression, higher sGC levels, and higher sGC activity after stimulation. Finally, human and mouse data link augmented sGC expression to lower risk of atherosclerosis. [ABSTRACT FROM AUTHOR]