A Pad 4 Plaque Erosion

Regulating NETs contributes to a novel antiatherogenic effect of MTHSWD via inhibiting endothelial injury and apoptosis

Neutrophil extracellular traps (NETs) are implicated in the occurrence and progression of atherosclerosis (AS), which can result in adverse cardiovascular events. We investigated the potential mechanism of action of Modified Taohong Siwu Decoction (MTHSWD) against AS based on its effect on NETs. A model of unstable plaque in AS was established by tandem stenosis (TS) of the right common carotid artery in ApoE-/- mice combined with a western diet (WD). The research found that MTHSWD reduced the weight of mice with AS to varying degrees, and significantly decreased the levels of plasma total cholesterol (TC) and triglycerides (TG). Meanwhile, we found that MTHSWD not only significantly improved cardiac EF, FS, cardiac hypertrophy, and ventricular remodeling, but also ameliorated the silent and depressed hypoactivity state caused by AS in ApoE-/- mice. Additionally, the study revealed that MTHSWD improved the severity of AS, protected the vascular structure, increased plaque stability and vessel patency. It also significantly reduced vascular cell apoptosis, platelet aggregation, and the presence of inflammatory cells such as neutrophils (NEUs), as well as the expression of neutrocyte elastase (NE) and myeloperoxidase (MPO), which are components of NETs. Subsequently, NEUs studies have shown that MTHSWD not only significantly reduces the dsDNA content of NETs, but also lowers the expression of NETs components NE and citH3. NETs treating the human umbilical vein endothelial cells (HUVECs) demonstrated that NETs differentially increased the protein expression of endothelial inflammatory adhesion factors CD62P, VCAM-1 and ICAM-1, while significantly decreasing the viability of HUVECs. Pharmacological treatment discovered that MTHSWD significantly improved HUVECs viability impaired by NETs, and promoted the growth and proliferation of endothelial cells. Furthermore, it significantly reduced early and late apoptosis of HUVECs caused by NETs, decreased the expression of pro-apoptotic proteins BAX and Cleaved-Caspase-3, and increased the expression of anti-apoptotic protein Bcl-2. Thus, study suggests that MTHSWD may improve body weight, lipid levels, cardiac function, vigour, and the severity of AS in ApoE-/- AS mice. The novel effect of MTHSWD against AS may be attributed to the inhibition of endothelial injury and apoptosis through the regulation of NETs. This, in turn, reduces the levels of platelets, inflammatory cells, and components of NETs in AS plaques, achieving a benign cycle that protects endothelial cells and vascular structure and function. This result provides some clues and evidence for studying the mechanism of action and clinical application of MTHSWD and its active ingredients against AS.

Neutrophils and Neutrophil Extracellular Traps in Cardiovascular Disease: An Overview and Potential Therapeutic Approaches

Recent advances in pharmacotherapy have markedly improved the prognosis of cardiovascular disease (CVD) but have not completely conquered it. Therapies targeting the NOD-like receptor family pyrin domain containing 3 inflammasome and its downstream cytokines have proven effective in the secondary prevention of cardiovascular events, suggesting that inflammation is a target for treating residual risk in CVD. Neutrophil-induced inflammation has long been recognized as important in the pathogenesis of CVD. Circadian rhythm-related and disease-specific microenvironment changes give rise to neutrophil diversity. Neutrophils are primed by various stimuli, such as chemokines, cytokines, and damage-related molecular patterns, and the activated neutrophils contribute to the inflammatory response in CVD through degranulation, phagocytosis, reactive oxygen species generation, and the release of neutrophil extracellular traps (NETs). In particular, NETs promote immunothrombosis through the interaction with vascular endothelial cells and platelets and are implicated in the development of various types of CVD, such as acute coronary syndrome, deep vein thrombosis, and heart failure. NETs are promising candidates for anti-inflammatory therapy in CVD, and their efficacy has already been demonstrated in various animal models of the disease; however, they have yet to be clinically applied in humans. This narrative review discusses the diversity and complexity of neutrophils in the trajectory of CVD, the therapeutic potential of targeting NETs, and the related clinical issues.

Plaque erosion and acute coronary syndromes: phenotype, molecular characteristics and future directions

Although acute coronary syndromes (ACS) remain one of the leading causes of death, the clinical presentation has changed over the past three decades with a decline in the incidence of ST-segment elevation myocardial infarction (STEMI) and an increase in non-STEMI. This epidemiological shift is at least partially explained by changes in plaque biology as a result of the widespread use of statins. Historically, atherosclerotic plaque rupture of the fibrous cap was thought to be the main culprit in ACS. However, plaque erosion with an intact fibrous cap is now responsible for about one third of ACS and up to two thirds of non-STEMI. Two major research approaches have enabled a better understanding of plaque erosion. First, advanced intravascular imaging has provided opportunities for an 'optical biopsy' and extensive phenotyping of coronary plaques in living patients. Second, basic science experiments have shed light on the unique molecular characteristics of plaque erosion. At present, patients with ACS are still uniformly treated with coronary stents irrespective of the underlying pathobiology. However, pilot studies indicate that patients with plaque erosion might be treated conservatively without coronary stenting. In this Review, we discuss the patient phenotype and the molecular characteristics in atherosclerotic plaque erosion and provide our vision for a potential major shift in the management of patients with plaque erosion.

Physical exertion as a trigger of acute coronary syndrome caused by plaque erosion

Distinct clinical characteristics have been demonstrated in patients with plaque erosion as compared with those with plaque rupture. We reasoned that greater physical activity might influence the onset of plaque erosion. In total, 97 consecutive patients with non ST-segment elevation acute coronary syndrome (ACS) who underwent optical coherence tomography (OCT) imaging of the culprit lesion were enrolled. OCT-determined culprit plaque characteristics were plaque erosion (18.6%), calcified plaque (26.8%), plaque rupture (32.0%) and other (22.7%). The physical activity evaluated by estimated metabolic equivalents (METs) at ACS onset was significantly greater in the plaque erosion group than in the plaque rupture group (3.3 ± 1.7 vs. 2.1 ± 1.0, p = 0.011). The rate of ACS onset outdoors was the highest (61.1%) in the plaque erosion group. The combination of greater physical activity (> 3 METs), outdoor onset and higher body mass index (> 25.1 kg/m²) had a significant odds ratio for the incidence of plaque erosion (odds ratio 15.0, 95% confidence interval 3.81 to 59.0, p < 0.001). Plaque erosion was associated with greater physical activity at the onset. This finding may help to further clarify the pathogenesis of ACS Impact of physical exertion on the incidence of plaque erosion. NSTE-ACS, non ST-segment elevation acute coronary syndrome.

New prediction tools and treatment for ACS patients with plaque erosion

For decades, we have known from autopsy observations that the proximate cause of the majority of acute coronary syndromes ( ACS) is occlusive thrombosis generated by plaque rupture or, less frequently, superficial erosion. Patients with ACS caused by plaque erosion seem to have a better long-term prognosis compared to those with plaque rupture, and may be stabilized by dual antiplatelet therapy without the need for stenting in a non-trivial proportion of cases, limiting the expenses and potential complications of invasive procedures. The accurate prediction of plaque erosion and the identification of specific biomarkers that could be used at the point-of-care without the need of invasive imaging would take us a step closer to the holy grail of precision medicine in patients with ACS.

Reassessing the Mechanisms of Acute Coronary Syndromes

The mechanisms that underlie superficial erosion, a cause of coronary thrombosis distinct from plaque rupture, have garnered recent interest. In an era of improved control of traditional risk factors, such as LDL (low-density lipoprotein), plaque erosion may assume greater clinical importance. Plaques complicated by erosion tend to be matrix-rich, lipid-poor, and usually lack prominent macrophage collections, unlike plaques that rupture, which characteristically have thin fibrous caps, large lipid pools, and abundant foam cells. Thrombi that complicate superficial erosion seem more platelet-rich than the fibrinous clots precipitated by plaque rupture. The pathogenesis of plaque rupture probably does not pertain to superficial erosion, a process heretofore little understood mechanistically. We review here data that support a substantial shift in the mechanisms of the thrombotic complications of atherosclerosis. We further consider pathophysiologic processes recently implicated in the mechanisms of erosion. Multiple processes likely predispose plaques to superficial erosion, including experiencing disturbed flow, basement membrane breakdown, endothelial cell death, and detachment potentiated by innate immune activation mediated through pattern-recognition receptors and endothelial-to-mesenchymal transition. Monocytes/macrophages predominate in the pathogenesis of plaque rupture and consequent thrombosis, but polymorphonuclear leukocytes likely promote endothelial damage during superficial erosion. The formation of neutrophil extracellular traps probably perpetuates and propagates intimal injury and potentiates thrombosis due to superficial erosion. These considerations have profound clinical implications. Acute coronary syndromes because of erosion may not require immediate invasive therapy. Understanding the biological bases of erosion points to novel therapies for acute coronary syndrome caused by erosion. Future research should probe further the mechanisms of superficial erosion, and develop point-of-care tests to distinguish acute coronary syndromes provoked by erosion versus rupture that may direct more precision management. Future clinical investigations should evaluate intervening on the targets that have emerged from experimental studies and the management strategies that they inform.