Discoidin Domain-Containing Receptor 2 Is Present in Human Atherosclerotic Plaques and Involved in the Expression and Activity of MMP-2

Discoidin domain-containing receptor 2 (DDR2) has been suggested to be involved in atherosclerotic progression, but its pathological role remains unknown. Using immunochemical staining, we located and compared the expression of DDR2 in the atherosclerotic plaques of humans and various animal models. Then, siRNA was applied to knock down the expression of DDR2 in vascular smooth muscle cells (VSMCs), and the migration, proliferation, and collagen Ι-induced expression of matrix metalloproteinases (MMPs) were evaluated. We found that an abundance of DDR2 was present in the atherosclerotic plaques of humans and various animal models and was distributed around fatty and necrotic cores. After incubation of oxidized low-density lipoprotein (ox-LDL), DDR2 was upregulated in VSMCs in response to such a proatherosclerotic condition. Next, we found that decreased DDR2 expression in VSMCs inhibited the migration, proliferation, and collagen Ι-induced expression of matrix metalloproteinases (MMPs). Moreover, we found that DDR2 is strongly associated with the protein expression and activity of MMP-2, suggesting that DDR2 might play a role in the etiology of unstable plaques. Considering that DDR2 is present in the atherosclerotic plaques of humans and is associated with collagen Ι-induced secretion of MMP-2, the clinical role of DDR2 in cardiovascular disease should be elucidated in further experiments.

Features of atherosclerosis in carotid and coronary arteries

Atherothrombosis is a leading cause of myocardial infarction and ischemic atherothrombotic stroke. It represents a stage of atherosclerosis which is a pathologic process throughout the circulatory system. However, atherosclerosis has specific development characteristics in different vascular beds. Multiple factors contribute to atherosclerosis formation and progression such as genetic factors, vessel hemodynamics, and vessel anatomy. A better understanding of differences in vessels would improve prevention and treatment of atherosclerosis and its complication. In this article we review features of atherosclerosis in carotid and coronary vessels. We discuss specific conditions of local hemodynamics in the areas of bifurcation which promote atherosclerotic plaque progression, and review characteristics of unstable plaques in carotid and coronary vessels. We analyze immunologic and inflammatory processes, extracellular matrix degradation and remodeling, cellular apoptosis and autophagy occurring during atherosclerotic plaque destabilization as well as the possibility of diffuse plaque instability in systemic atherosclerosis. We review association and interaction of atherosclerotic processes in coronary and carotid arteries, and its significance for a patient. Improvement in understanding of atherosclerosis pathogenesis can lead to advances in atherosclerosis prevention. Timely and effective interventions would promote prevention of myocardial infarction and ischemic stroke which is highly important taking into account high mortality and morbidity rates.

PFKFB3 gene deletion in endothelial cells inhibits intraplaque angiogenesis and lesion formation in a murine model of venous bypass grafting

Vein grafting is a frequently used surgical intervention for cardiac revascularization. However, vein grafts display regions with intraplaque (IP) angiogenesis, which promotes atherogenesis and formation of unstable plaques. Graft neovessels are mainly composed of endothelial cells (ECs) that largely depend on glycolysis for migration and proliferation. In the present study, we aimed to investigate whether loss of the glycolytic flux enzyme phosphofructokinase-2/fructose-2,6-bisphosphatase 3 (PFKFB3) in ECs inhibits IP angiogenesis and as such prevents unstable plaque formation. To this end, apolipoprotein E deficient (ApoE−/−) mice were backcrossed to a previously generated PFKFB3fl/fl Cdh5iCre mouse strain. Animals were injected with either corn oil (ApoE−/−PFKFB3fl/fl) or tamoxifen (ApoE−/−PFKFB3ECKO), and were fed a western-type diet for 4 weeks prior to vein grafting. Hereafter, mice received a western diet for an additional 28 days and were then sacrificed for graft assessment. Size and thickness of vein graft lesions decreased by 35 and 32%, respectively, in ApoE−/−PFKFB3ECKO mice compared to controls, while stenosis diminished by 23%. Moreover, vein graft lesions in ApoE−/−PFKFB3ECKO mice showed a significant reduction in macrophage infiltration (29%), number of neovessels (62%), and hemorrhages (86%). EC-specific PFKFB3 deletion did not show obvious adverse effects or changes in general metabolism. Interestingly, RT-PCR showed an increased M2 macrophage signature in vein grafts from ApoE−/−PFKFB3ECKO mice. Altogether, EC-specific PFKFB3 gene deletion leads to a significant reduction in lesion size, IP angiogenesis, and hemorrhagic complications in vein grafts. This study demonstrates that inhibition of endothelial glycolysis is a promising therapeutic strategy to slow down plaque progression.

Micro-RNA as a predictor of cardiovascular diseases

Сердечно-сосудистые заболевания, особенно ишемическая болезнь сердца (ИБС), являются наиболее распространенными заболеваниями во всем мире. Более 50% смертности приходится на данную патологию. В последние десятилетия существует тенденция к «омоложению» сердечно-сосудистых заболеваний – прежде всего гипертонической болезни и ИБС, что вызывает особую тревогу. Общепризнано, что основным этиологическим моментом развития ИБС является атеросклероз. ИБС включает в себя целый ряд клинических диагнозов (стенокардия, инфаркт миокарда и т. д.) и связана с атеросклерозом, распространенным дегенеративным заболеванием, при котором липиды и фиброзный матрикс откладываются в артериальной стенке с формированием атероматозной бляшки. Разрыв нестабильных бляшек в коронарных артериях приводит к высвобождению тромбогенного содержимого в просвет сосуда, приводя к тромбозу коронарных артерий, окклюзии и последующему инфаркту миокарда – критическому состоянию с высокой смертностью [5]. Несмотря на большое количество известных факторов риска, влияющих на развитие данного заболевания, существуют данные, подтвержденные крупными исследованиями, о наличии генетической предрасположенности к нему. Cardiovascular diseases, especially coronary heart disease (CHD), are the most common diseases worldwide. More than 50% of mortality occurs in this pathology. In recent decades, there is a tendency to «rejuvenate» cardiovascular diseases – primarily hypertension and СHD, which is of particular concern [6, 8]. It is generally recognized that atherosclerosis is the main etiological moment in the development of coronary heart disease. CHD includes a number of clinical diagnoses (angina pectoris, myocardial infarction, etc.) and is associated with atherosclerosis, a common degenerative disease in which lipids and the fibrous matrix are deposited in the arterial wall with the formation of an atheromatous plaque. Rupture of unstable plaques in the coronary arteries leads to the release of thrombogenic contents into the lumen of the vessel, leading to coronary artery thrombosis, occlusion and subsequent myocardial infarction, critical state with high mortality [5]. Despite the large number of known risk factors affecting the development of this disease, there is evidence, confirmed by large studies, about the presence of a genetic predisposition to this disease.

Clinical Implications of IL-32, IL-34 and IL-37 in Atherosclerosis: Speculative Role in Cardiovascular Manifestations of COVID-19

Atherosclerosis, which is a primary cause of cardiovascular disease (CVD) deaths around the world, is a chronic inflammatory disease that is characterised by the accumulation of lipid plaques in the arterial wall, triggering inflammation that is regulated by cytokines/chemokines that mediate innate and adaptive immunity. This review focuses on IL-32, -34 and -37 in the stable vs. unstable plaques from atherosclerotic patients. Dysregulation of the novel cytokines IL-32, -34 and -37 has been discovered in atherosclerotic plaques. IL-32 and -34 are pro-atherogenic and associated with an unstable plaque phenotype; whereas IL-37 is anti-atherogenic and maintains plaque stability. It is speculated that these cytokines may contribute to the explanation for the increased occurrence of atherosclerotic plaque rupture seen in patients with COVID-19 infection. Understanding the roles of these cytokines in atherogenesis may provide future therapeutic perspectives, both in the management of unstable plaque and acute coronary syndrome, and may contribute to our understanding of the COVID-19 cytokine storm.

Molecular and Nonmolecular Imaging of Macrophages in Atherosclerosis

Atherosclerosis is a major cause of ischemic heart disease, and the increasing medical burden associated with atherosclerotic cardiovascular disease has become a major public health concern worldwide. Macrophages play an important role in all stages of the dynamic progress of atherosclerosis, from its initiation and lesion expansion increasing the vulnerability of plaques, to the formation of unstable plaques and clinical manifestations. Early imaging can identify patients at risk of coronary atherosclerotic disease and its complications, enabling preventive measures to be initiated. Recent advances in molecular imaging have involved the noninvasive and semi-quantitative targeted imaging of macrophages and their related molecules in vivo, which can detect atheroma earlier and more accurately than conventional imaging. Multimodal imaging integrates vascular structure, function, and molecular imaging technology to achieve multi-dimensional imaging, which can be used to comprehensively evaluate blood vessels and obtain clinical information based on anatomical structure and molecular level. At the same time, the rapid development of nonmolecular imaging technologies, such as intravascular imaging, which have the unique advantages of having intuitive accuracy and providing rich information to identify macrophage inflammation and inform targeted personalized treatment, has also been seen. In this review, we highlight recent methods and research hotspots in molecular and nonmolecular imaging of macrophages in atherosclerosis that have enormous potential for rapid clinical application.

Lipoprotein-associated Phospholipase A2: Current Trends in Invitro Diagnostics

Lipoprotein-associated phospholipase A2 is an imminent reliable precise biomarker for vascular inflammation involved in the development of unstable plaques in cardiovascular diseases. The atherosclerotic plaque formation, inflammation and rupture of arterial vessels lead to heart attacks and strokes in most of the cases. The vessel-specific inflammatory enzyme, Lipoprotein-associated phospholipase A2 shoot ups in response to the rupture of arterial vessels having atherosclerotic plaques. The accurate measurement of Lipoprotein-associated phospholipase A2 envisages the individual risk of a patient and the treatment can be customized based on the result.

A prediction tool for plaque progression based on patient-specific multi-physical modeling

Atherosclerotic plaque rupture is responsible for a majority of acute vascular syndromes and this study aims to develop a prediction tool for plaque progression and rupture. Based on the follow-up coronary intravascular ultrasound imaging data, we performed patient-specific multi-physical modeling study on four patients to obtain the evolutional processes of the microenvironment during plaque progression. Four main pathophysiological processes, i.e., lipid deposition, inflammatory response, migration and proliferation of smooth muscle cells (SMCs), and neovascularization were coupled based on the interactions demonstrated by experimental and clinical observations. A scoring table integrating the dynamic microenvironmental indicators with the classical risk index was proposed to differentiate their progression to stable and unstable plaques. The heterogeneity of plaque microenvironment for each patient was demonstrated by the growth curves of the main microenvironmental factors. The possible plaque developments were predicted by incorporating the systematic index with microenvironmental indicators. Five microenvironmental factors (LDL, ox-LDL, MCP-1, SMC, and foam cell) showed significant differences between stable and unstable group (p < 0.01). The inflammatory microenvironments (monocyte and macrophage) had negative correlations with the necrotic core (NC) expansion in the stable group, while very strong positive correlations in unstable group. The inflammatory microenvironment is strongly correlated to the NC expansion in unstable plaques, suggesting that the inflammatory factors may play an important role in the formation of a vulnerable plaque. This prediction tool will improve our understanding of the mechanism of plaque progression and provide a new strategy for early detection and prediction of high-risk plaques.

Establishment of a Novel Mouse Model for Atherosclerotic Vulnerable Plaque

Background and Aims: Acute coronary syndrome (ACS) is a group of clinical syndromes characterized by rupture or erosion of atherosclerotic unstable plaques. Effective intervention for vulnerable plaques (VP) is of great significance to reduce adverse cardiovascular events.Methods: Fbn1C1039G+/− mice were crossbred with LDLR−/− mice to obtain a novel model for atherosclerotic VP. After the mice were fed with a high-fat diet (HFD) for 12 or 24 weeks, pathological staining and immunohistochemistry analyses were employed to evaluate atherosclerotic lesions.Results: Compared to control mice, Fbn1C1039G+/−LDLR−/− mice developed more severe atherosclerotic lesions, and the positive area of oil red O staining in the aortic sinus was significantly increased after 12 weeks (21.7 ± 2.0 vs. 6.3 ± 2.1) and 24 weeks (32.6 ± 2.5 vs. 18.7 ± 2.6) on a HFD. Additional vulnerable plaque characteristics, including significantly larger necrotic cores (280 ± 19 vs. 105 ± 7), thinner fiber caps (14.0 ± 2.8 vs. 32.6 ± 2.7), apparent elastin fiber fragmentation and vessel dilation (3,010 ± 67 vs. 1,465 ± 49), a 2-fold increase in macrophage number (8.5 ± 1.0 vs. 5.0 ± 0.6), obviously decreased smooth muscle cell number (0.6 ± 0.1 vs. 2.1 ± 0.2) and an ~25% decrease in total collagen content (33.6 ± 0.3 vs. 44.9 ± 9.1) were observed in Fbn1C1039G+/−LDLR−/− mice compared with control mice after 24 weeks. Furthermore, spontaneous plaque rupture, neovascularization, and intraplaque hemorrhage were detected in the model mouse plaque regions but not in those of the control mice.Conclusions: Plaques in Fbn1C1039G+/−LDLR−/− mice fed a HFD show many features of human advanced atherosclerotic unstable plaques. These results suggest that the Fbn1C1039G+/−LDLR−/− mouse is a novel model for investigating the pathological and physiological mechanisms of advanced atherosclerotic unstable plaques.

The Risk of Carotid Plaque Instability in Patients with Metabolic Syndrome: It is Higher in Women with Hypertriglyceridemia

Background: Metabolic syndrome certainly favors growth of carotid plaque; however, it is uncertain if it determines plaque destabilization. Furthermore, it is likely that only some components of metabolic syndrome are associated with increased risk of plaque destabilization. Therefore, we evaluated the effect of different elements of metabolic syndrome, individually and in association, on carotid plaques destabilization. Methods: A total of 186 carotid endarterectomies from symptomatic and asymptomatic patients were histologically analysed and correlated with major cardiovascular risk factors. Results: Metabolic syndrome, regardless of the cluster of its components, is not associated with a significant increase in risk of plaque destabilization, rather with the presence of stable plaques. The incidence of unstable plaques in patients with metabolic syndrome is quite low (43.9%), when compared with that seen in the presence of some risk factors, but significantly increases in the subgroup of female patients with hypertriglyceridemia, showing an odds ratio of 3.01 (CI 95% 0.25 - 36.30). Conclusions: Our data may help to identify patients with real increased risk of acute cerebrovascular diseases and may support the hypothesis that the control of hypertriglyceridemia should be a key point on prevention of carotid atherosclerotic plaque destabilization, especially in post-menopausal female patients. Keywords: Metabolic syndrome, carotid, histology, hypertriglyceridemia , post-menopause.