Vascular Inflammation in Subclinical Atherosclerosis Detected by Hybrid PET/MRI

Multi-targeted 1H/19F MRI unmasks specific danger patterns for emerging cardiovascular disorders

Prediction of the transition from stable to acute coronary syndromes driven by vascular inflammation, thrombosis with subsequent microembolization, and vessel occlusion leading to irreversible myocardial damage is still an unsolved problem. Here, we introduce a multi-targeted and multi-color nanotracer platform technology that simultaneously visualizes evolving danger patterns in the development of progressive coronary inflammation and atherothrombosis prior to spontaneous myocardial infarction in mice. Individual ligand-equipped perfluorocarbon nanoemulsions are used as targeting agents and are differentiated by their specific spectral signatures via implementation of multi chemical shift selective 19F MRI. Thereby, we are able to identify areas at high risk of and predictive for consecutive development of myocardial infarction, at a time when no conventional parameter indicates any imminent danger. The principle of this multi-targeted approach can easily be adapted to monitor also a variety of other disease entities and constitutes a technology with disease-predictive potential.

Quantitative Magnetic Resonance Imaging Assessment of the Relationships Between Fat Fraction and R2* Inside Carotid Plaques, and Circulating Lipoproteins

BACKGROUND

Lipid-rich necrotic core (LRNC) and intraplaque hemorrhage (IPH) are morphological features of high-risk atherosclerotic plaques. However, their relationship to circulating lipoproteins is unclear.

PURPOSE

To study associations between changes in lipoproteins vs. changes in LRNC (represented by fat fraction [FF]) and IPH (represented by R2*).

STUDY TYPE

Prospective.

SUBJECTS

Fifty-two patients with carotid plaques, 33 males (63.5%), mean age 72 (±5).

FIELD STRENGTH/SEQUENCE

Four-point fast gradient Dixon magnetic resonance imaging (MRI) was used to quantify FF and R2* (to measure IPH) inside plaques and in vessel wall. Turbo-spin echo was used for T₁ weighted sequences to guide manual segmentation.

ASSESSMENT

Carotid MRI and serum lipid levels were assessed at baseline and at 1-year follow-up. For patients, lipid-lowering therapy was customized to reduce low-density lipoprotein (LDL) levels below 1.8 mmol/L. Segmentation was performed with one set of regions of interest for the plaque and one for the vessel wall at the location of the plaque. Thereby MRI data for FF, R2*, and volumes in plaque- and vessel-wall segmentations could be obtained from baseline and follow-up, as well as changes over the study year.

STATISTICAL TESTS

Pearson correlation coefficient for correlations. Paired samples t-test for changes over time. Significance at P < 0.05, 95% confidence interval.

RESULTS

LDL decreased significantly (2.19-1.88 mmol/L, Z - 2.9), without correlation to changes in plaque composition, nor to the significant reduction in vessel-wall volume (-106.3 mm³ ). Plaque composition remained unchanged, FF +8.5% (P = 0.366) and R2* +3.5% (P = 0.304). Compared to plaque segmentations, R2* was significantly lower in the vessel-wall segmentations both at baseline (-9.3%) and at follow-up (-9.1%).

DATA CONCLUSION

The absence of correlations between changes in lipoproteins and changes in plaque composition indicates more complex relationships between these parameters than previously anticipated. The significant differences in both R2* and volume dynamics comparing plaque segmentations and vessel-wall segmentations suggest differences in their pathobiology of atherosclerosis.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY: Stage 4.

Application of a Reactive Oxygen Species-Responsive Drug-Eluting Coating for Surface Modification of Vascular Stents

Stent implantation is the primary method used to treat coronary heart disease. However, it is associated with complications such as restenosis and late thrombosis. Despite surface modification being an effective way to improve the biocompatibility of stents, the current research studies are not focused on changes in the vascular microenvironment at the implantation site. In the present study, an adaptive drug-loaded coating was constructed on the surface of vascular stent materials that can respond to oxidative stress at the site of vascular lesions. Two functional molecules, epigallocatechin gallate (EGCG) and cysteine hydrochloride, were employed to fabricate a coating on the surface of 316L stainless steel. In addition, the coating was used as a drug carrier to load pitavastatin calcium. EGCG has antioxidant activity, and pitavastatin calcium can inhibit smooth muscle cell proliferation. Therefore, EGCG and pitavastatin calcium provided a synergistic anti-inflammatory effect. Moreover, the coating was cross-linked using disulfide bonds, which accelerated the release of the drug in response to reactive oxygen species. A positive correlation was observed between the rate of drug release and the degree of oxidative stress. Collectively, this drug-loaded oxidative stress-responsive coating has been demonstrated to significantly inhibit inflammation, accelerate endothelialization, and reduce the risk of restenosis of vascular stents in vivo.

Antithrombotic therapies in aortic and peripheral arterial diseases in 2021: a consensus document from the ESC working group on aorta and peripheral vascular diseases, the ESC working group on thrombosis, and the ESC working group on cardiovascular pharmacotherapy

The aim of this collaborative document is to provide an update for clinicians on best antithrombotic strategies in patients with aortic and/or peripheral arterial diseases. Antithrombotic therapy is a pillar of optimal medical treatment for these patients at very high cardiovascular risk. While the number of trials on antithrombotic therapies in patients with aortic or peripheral arterial diseases is substantially smaller than for those with coronary artery disease, recent evidence deserves to be incorporated into clinical practice. In the absence of specific indications for chronic oral anticoagulation due to concomitant cardiovascular disease, a single antiplatelet agent is the basis for long-term antithrombotic treatment in patients with aortic or peripheral arterial diseases. Its association with another antiplatelet agent or low-dose anticoagulants will be discussed, based on patient's ischaemic and bleeding risk as well therapeutic paths (e.g. endovascular therapy). This consensus document aims to provide a guidance for antithrombotic therapy according to arterial disease localizations and clinical presentation. However, it cannot substitute multidisciplinary team discussions, which are particularly important in patients with uncertain ischaemic/bleeding balance. Importantly, since this balance evolves over time in an individual patient, a regular reassessment of the antithrombotic therapy is of paramount importance.

18Fluorodeoxyglucose uptake in relation to fat fraction and R2* in atherosclerotic plaques, using PET/MRI: a pilot study

Inflammation inside Atherosclerotic plaques represents a major pathophysiological process driving plaques towards rupture. Pre-clinical studies suggest a relationship between lipid rich necrotic core, intraplaque hemorrhage and inflammation, not previously explored in patients. Therefore, we designed a pilot study to investigate the feasibility of assessing the relationship between these plaque features in a quantitative manner using PET/MRI. In 12 patients with high-grade carotid stenosis the extent of lipid rich necrotic core and intraplaque hemorrhage was quantified from fat and R2* maps acquired with a previously validated 4-point Dixon MRI sequence in a stand-alone MRI. PET/MRI was used to measure ¹⁸F-FDG uptake. T1-weighted images from both scanners were used for registration of the quantitative Dixon data with the PET images. The plaques were heterogenous with respect to their volumes and composition. The mean values for the group were as follows: fat fraction (FF) 0.17% (± 0.07), R2* 47.6 s⁻¹ (± 10.9) and target-to-blood pool ratio (TBR) 1.49 (± 0.48). At group level the correlation between TBR and FF_mean was − 0.406, p 0.19 and for TBR and R2*_mean 0.259, p 0.42. The lack of correlation persisted when analysed on a patient-by-patient basis but the study was not powered to draw definitive conclusions. We show the feasibility of analysing the quantitative relationship between lipid rich necrotic cores, intraplaque haemorrhage and plaque inflammation. The ¹⁸F-FDG uptake for most patients was low. This may reflect the biological complexity of the plaques and technical aspects inherent to ¹⁸F-FDG measurements.

Trial registration: ISRCTN, ISRCTN30673005. Registered 05 January 2021, retrospectively registered.

Progression of Early Subclinical Atherosclerosis (PESA) Study: JACC Focus Seminar 7/8

Atherosclerosis starts early in life and progresses silently for decades. Considering atherosclerosis as a "systemic disease" invites the use of noninvasive methodologies to detect disease in various regions before symptoms appear. The PESA-(Progression of Early Subclinical Atherosclerosis) CNIC-SANTANDER study is an ongoing prospective cohort study examining imaging, biological, and behavioral parameters associated with the presence and progression of early subclinical atherosclerosis. Between 2010 and 2014, PESA enrolled 4,184 asymptomatic middle-aged participants who undergo serial 3-yearly follow-up examinations including clinical interviews, lifestyle questionnaires, sampling, and noninvasive imaging assessment of multiterritorial subclinical atherosclerosis (carotids, iliofemorals, aorta, and coronaries). PESA tracks the trajectories of atherosclerosis and associated disorders from early stages to the transition to symptomatic phases. A joint venture between the CNIC and the Santander Bank, PESA is expected to run until at least 2029, and its significant contributions to date are presented in this review paper.

Risk factors for symptomatic vascular events in giant cell arteritis: a study of 254 patients with large-vessel imaging at diagnosis

Aims

To identify factors associated with vascular events in patients with giant cell arteritis (GCA).

Methods

We performed a retrospective study of GCA patients diagnosed over a 20-year-period, who all underwent vascular imaging evaluation at diagnosis. Symptomatic vascular events were defined as the occurrence of any aortic event (aortic dissection or symptomatic aortic aneurysm), stroke, myocardial infarction, limb or mesenteric ischemia and de novo lower limbs arteritis stage 3 or 4. Patients with symptomatic vascular event (VE+) and without were compared, and risk factors were identified in a multivariable analysis.

Results

Thirty-nine (15.4%) of the 254 included patients experienced at least one symptomatic vascular event during follow-up, with a median time of 21.5 months. Arterial hypertension, diabetes, lower limbs arteritis or vascular complication at diagnosis were more frequent in VE+ patients (p < 0.05), as an abnormal computed tomography (CT)-scan at diagnosis (p = 0.04), aortitis (p = 0.01), particularly of the descending thoracic aorta (p = 0.03) and atheroma (p = 0.03). Deaths were more frequent in the VE+ group (37.1 versus 10.3%, p = 0.0003). In multivariable analysis, aortic surgery [hazard ratio (HR): 10.46 (1.41-77.80), p = 0.02], stroke [HR: 22.32 (3.69-135.05), p < 0.001], upper limb ischemia [HR: 20.27 (2.05-200.12), p = 0.01], lower limb ischemia [HR: 76.57 (2.89-2027.69), p = 0.009], aortic atheroma [HR: 3.06 (1.06-8.82), p = 0.04] and aortitis of the descending thoracic aorta on CT-scan at diagnosis [HR: 4.64 (1.56-13.75), p = 0.006] were independent predictive factors of a vascular event.

Conclusion

In this study on GCA cases with large vessels imaging at diagnosis, aortic surgery, stroke, upper or lower limb ischemia, aortic atheroma and aortitis of the descending thoracic aorta on CT-scan, at GCA diagnosis, were independent predictive factors of a vascular event.

Plain language summary

Risk factors for symptomatic vascular events in giant cell arteritisThis study was performed to identify the risk factors for developing symptomatic vascular event during giant cell arteritis (GCA) because these are poorly known.We performed a retrospective study of GCA patients diagnosed over a 20-year-period, who all underwent vascular imaging evaluation at diagnosis.Patients with symptomatic vascular event (VE+) and without (VE-) were compared, and risk factors were identified in a multivariable analysis.Thirty-nine patients experienced at least one symptomatic vascular event during follow-up, with a median time of 21.5 months.Arterial hypertension, diabetes, lower limbs arteritis or vascular complication at diagnosis were significantly more frequent in VE+ patients, as an abnormal CT-scan at diagnosis, aortitis, particularly of the descending thoracic aorta and atheroma. Deaths were more frequent in the VE+ group.Among 254 GCA patients, 39 experienced at least one vascular event during follow-up.Aortic surgery, stroke, upper and lower limb ischemia were vascular event risk factors.Aortic atheroma and descending thoracic aorta aortitis on CT-scan were vascular event risk factors.This study on GCA cases with large vessels imaging at diagnosis, showed that aortic surgery, stroke, upper or lower limb ischemia, aortic atheroma and aortitis of the descending thoracic aorta on CT-scan, at GCA diagnosis, were independent predictive factors of a vascular event.

Atherosclerosis imaging using PET: Insights and applications

PET imaging is able to harness biological processes to characterise high-risk features of atherosclerotic plaque prone to rupture. Current radiotracers are able to track inflammation, microcalcification, hypoxia, and neoangiogenesis within vulnerable plaque. 18 F-fluorodeoxyglucose (18 F-FDG) is the most commonly used radiotracer in vascular studies and is employed as a surrogate marker of plaque inflammation. Increasingly, 18 F-FDG and other PET tracers are also being used to provide imaging endpoints in cardiovascular interventional trials. The evolution of novel PET radiotracers, imaging protocols, and hybrid scanners are likely to enable more efficient and accurate characterisation of high-risk plaque. This review explores the role of PET imaging in atherosclerosis with a focus on PET tracers utilised in clinical research and the applications of PET imaging to cardiovascular drug development.

Triglycerides and Residual Atherosclerotic Risk

BACKGROUND

Even when low-density lipoprotein-cholesterol (LDL-C) levels are lower than guideline thresholds, a residual risk of atherosclerosis remains. It is unknown whether triglyceride (TG) levels are associated with subclinical atherosclerosis and vascular inflammation regardless of LDL-C.

OBJECTIVES

This study sought to assess the association between serum TG levels and early atherosclerosis and vascular inflammation in apparently healthy individuals.

METHODS

An observational, longitudinal, and prospective cohort study, including 3,754 middle-aged individuals with low to moderate cardiovascular risk from the PESA (Progression of Early Subclinical Atherosclerosis) study who were consecutively recruited between June 2010 and February 2014, was conducted. Peripheral atherosclerotic plaques were assessed by 2-dimensional vascular ultrasound, and coronary artery calcification (CAC) was assessed by noncontrast computed tomography, whereas vascular inflammation was assessed by fluorine-18 fluorodeoxyglucose uptake on positron emission tomography.

RESULTS

Atherosclerotic plaques and CAC were observed in 58.0% and 16.8% of participants, respectively, whereas vascular inflammation was evident in 46.7% of evaluated participants. After multivariate adjustment, TG levels ≥150 mg/dl showed an association with subclinical noncoronary atherosclerosis (odds ratio [OR]: 1.35; 95% confidence interval [CI]: 1.08 to 1.68; p = 0.008). This association was significant for groups with high LDL-C (OR: 1.42; 95% CI: 1.11 to 1.80; p = 0.005) and normal LDL-C (OR: 1.85; 95% CI: 1.08 to 3.18; p = 0.008). No association was found between TG level and CAC score. TG levels ≥150 mg/dl were significantly associated with the presence of arterial inflammation (OR: 2.09; 95% CI: 1.29 to 3.40; p = 0.003).

CONCLUSIONS

In individuals with low to moderate cardiovascular risk, hypertriglyceridemia was associated with subclinical atherosclerosis and vascular inflammation, even in participants with normal LDL-C levels. (Progression of Early Subclinical Atherosclerosis [PESA]; NCT01410318).

Multimodality imaging for the prevention of cardiovascular events: Coronary artery calcium and beyond

Atherosclerotic cardiovascular disease (ASCVD) has been the leading cause of death worldwide for more than a decade. Prevention is of utmost importance to reduce related mortality. The innovations in cardiovascular imaging technology, in addition to our improved understanding of coronary atherosclerosis pathogenesis, have resulted in cardiovascular imaging becoming one of the most influential tools for diagnosis and risk stratification in ASCVD. Although numerous publications have emerged on this topic, data that guide routine cardiology clinical practice currently focus on the utility of a limited number of such modalities, namely arterial ultrasonography and computed tomography. Herein, current evidence with respect to the role of multimodality cardiovascular imaging on ASCVD prevention will be reviewed.

The year in cardiology: imaging

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Sleep duration and vascular inflammation using hybrid positron emission tomography/magnetic resonance imaging: results from the Multi-Ethnic Study of Atherosclerosis (MESA)

STUDY OBJECTIVES

Short sleep duration (SD) is associated with cardiovascular disease (CVD). We investigated the relationship between objective SD and subclinical atherosclerosis employing hybrid PET/MRI with ¹⁸F-FDG tracer in the MESA cohort.

METHODS

We utilized data from MESA-SLEEP and MESA-PET ancillary studies. SD and sleep fragmentation index (SFI) were assessed using 7-day actigraphy. The primary and secondary outcomes were carotid inflammation, defined using target-to-background ratios (TBR), and measures of carotid wall remodeling (carotid wall thickness [CWT]), summarized by SD category. Multivariate linear regression was performed to assess the association between SD and SFI with the primary/secondary outcomes, adjusting for several covariates including apnea-hypopnea index (AHI), and CVD risk.

RESULTS

Our analytical sample (n=58) was 62% female (mean age 68±8.4 years). Average SD was 5.1±0.9 hours in the short SD group (≤6 hours/night, 31%), and 7.1±0.8 hours in the normal SD group (69%). Prevalence of pathologic vascular inflammation (TBRmax>1.6) was higher in the short SD group (89% vs. 53%, p=0.009). Those with short SD had a higher TBRmax (1.77 vs 1.71), though this was not statistically significant (p=0.39). CWT was positively correlated with SFI even after adjusting for covariates (Beta [SE]=0.073±[0.032], p=0.025).

CONCLUSIONS

Prevalence of pathologic vascular inflammation was higher among those who slept ≤6 hours, and vascular inflammation was higher among those with a SD of ≤6 hours. Interestingly, SFI was positively correlated with CWT even after adjustment for covariates. Our results are hypothesis-generating but suggest that both habitual SD and SFI should be investigated in future studies as potential risk factors for subclinical atherosclerosis.

The Use of Imaging Techniques in Chronic Kidney Disease-Mineral and Bone Disorders (CKD-MBD)-A Systematic Review

Although frequently silent, mineral and bone disease (MBD) is one of the most precocious complication of chronic kidney disease (CKD) and is omnipresent in patients with CKD stage 5. Its pathophysiology is complex, but basically, disturbances in vitamin D, phosphate, and calcium metabolism lead to a diverse range of clinical manifestations with secondary hyperparathyroidism usually being the most frequent. With the decline in renal function, CKD-MBD may induce microstructural changes in bone, vascular system and soft tissues, which results in macrostructural lesions, such as low bone mineral density (BMD) resulting in skeletal fractures, vascular and soft tissue calcifications. Moreover, low BMD, fractures, and vascular calcifications are linked with increased risk of cardiovascular mortality and all-cause mortality. Therefore, a better characterization of CKD-MBD patterns, beyond biochemical markers, is helpful to adapt therapies and monitor strategies as used in the general population. An in-depth characterization of bone health is required, which includes an evaluation of cortical and trabecular bone structure and density and the degree of bone remodeling through bone biomarkers. Standard radiological imaging is generally used for the diagnosis of fracture or pseudo-fractures, vascular calcifications and other features of CKD-MBD. However, bone fractures can also be diagnosed using computed tomography (CT) scan, magnetic resonance (MR) imaging and vertebral fracture assessment (VFA). Fracture risk can be predicted by bone densitometry using dual-energy X-ray absorptiometry (DXA), quantitative computed tomography (QTC) and peripheral quantitative computed tomography (pQTC), quantitative ultrasound (QUS) and most recently magnetic resonance micro-imaging. Quantitative methods to assess bone consistency and strength complete the study and adjust the clinical management when integrated with clinical factors. The aim of this review is to provide a brief and comprehensive update of imaging techniques available for the diagnosis, prevention, treatment and monitoring of CKD-MBD.

The changing landscape of atherosclerosis

Emerging evidence has spurred a considerable evolution of concepts relating to atherosclerosis, and has called into question many previous notions. Here I review this evidence, and discuss its implications for understanding of atherosclerosis. The risk of developing atherosclerosis is no longer concentrated in Western countries, and it is instead involved in the majority of deaths worldwide. Atherosclerosis now affects younger people, and more women and individuals from a diverse range of ethnic backgrounds, than was formerly the case. The risk factor profile has shifted as levels of low-density lipoprotein (LDL) cholesterol, blood pressure and smoking have decreased. Recent research has challenged the protective effects of high-density lipoprotein, and now focuses on triglyceride-rich lipoproteins in addition to low-density lipoprotein as causal in atherosclerosis. Non-traditional drivers of atherosclerosis-such as disturbed sleep, physical inactivity, the microbiome, air pollution and environmental stress-have also gained attention. Inflammatory pathways and leukocytes link traditional and emerging risk factors alike to the altered behaviour of arterial wall cells. Probing the pathogenesis of atherosclerosis has highlighted the role of the bone marrow: somatic mutations in stem cells can cause clonal haematopoiesis, which represents a previously unrecognized but common and potent age-related contributor to the risk of developing cardiovascular disease. Characterizations of the mechanisms that underpin thrombotic complications of atherosclerosis have evolved beyond the 'vulnerable plaque' concept. These advances in our understanding of the biology of atherosclerosis have opened avenues to therapeutic interventions that promise to improve the prevention and treatment of now-ubiquitous atherosclerotic diseases.

An intelligent T1-T2 switchable MRI contrast agent for the non-invasive identification of vulnerable atherosclerotic plaques

Unlike stable atherosclerotic plaques, vulnerable plaques are very likely to cause serious cardio-cerebrovascular diseases. Meanwhile, how to non-invasively identify vulnerable plaques at early stages has been an urgent but challenging problem in clinical practices. Here, we propose a macrophage-targeted and in situ stimuli-triggered T₁-T₂ switchable magnetic resonance imaging (MRI) nanoprobe for the non-invasive diagnosis of vulnerable plaques. Precisely, single-dispersed iron oxide nanoparticles (IONPs) modified with hyaluronic acid (HA), denoted as IONP-HP, show macrophage targetability and T₁ MRI enhancement (r₂/r₁ = 3.415). Triggered by the low pH environment of macrophage lysosomes, the single-dispersed IONP-HP transforms into a cluster analogue, which exhibits T₂ MRI enhancement (r₂/r₁ = 13.326). Furthermore, an in vivo switch of T₁-T₂ enhancement modes shows that the vulnerable plaques exhibit strong T₁ enhancement after intravenous administration of the nanoprobe, followed by a switch to T₂ enhancement after 9 h. In contrast, stable plaques show only slight T₁ enhancement but without T₂ enhancement. It is therefore imperative that the intelligent and novel nanoplatform proposed in this study achieves a substantial non-invasive diagnosis of vulnerable plaques by means of a facile but effective T₁-T₂ switchable process, which will significantly contribute to the application of materials science in solving clinical problems.

[Association of AGT, ACE, NOS3, TNF, MMP9, CYBA polymorphism with subclinical arterial wall changes]

Aim    Activation of the renin-angiotensin-aldosterone system, decreased nitric oxide production, chronic inflammation, and oxidative stress result in subclinical changes in the arterial wall, which favor the development of cardiovascular diseases (CVD). The effect of allelic gene variants that encode the proteins participating in pathogenetic pathways of age-associated diseases with subclinical changes in the arterial wall [increased pulse wave velocity (PWV), increased intima-media thickness, endothelial dysfunction (ED), presence of atherosclerotic plaques (ASP)] are understudied. This study analyzed the relationship between AGT, ACE, NOS3 TNF, MMP9, and CYBA gene polymorphism and the presence of subclinical changes in the arterial wall, including the dependence on risk factors for CVD, in arbitrarily healthy people of various age.Material and methods    The relationship of polymorphisms с.521С&gt;Т of AGT gene, Ins&gt;Del of AСE gene, с.894G&gt;T of NOS3 gene, - 238G&gt;A of TNF gene, - 1562С&gt;T of MMP9 gene, and c.214Т&gt;С of CYBA gene with indexes of changes in the arterial wall and risk factors for CVD was studied in 160 arbitrarily healthy people by building models of multiple logistic regression and also by analyzing frequencies of co-emergence of two signs with the Pearson chi-squared test (χ2) and Fisher exact test.Results    The DD-genotype of Ins&gt;Del ACE gene polymorphism was correlated with increased PWV (p=0.006; odds ratio (OR) =3.41, 95 % confidence interval (CI): 1.48-8.67) and ED (p=0.014; OR=2.60, 95 % CI: 1.22-5.68). The GG genotype of с.894G&gt;T NOS3 gene polymorphism was correlated with ED (p=0.0087; OR=2.65, 95 % CI: 1.26-5.72); the ТТ-genotype of с.894G&gt;T NOS3 gene polymorphism was correlated with ASP (p=0.033; OR=0.034, 95 % CI: 0.001-0.549).Conclusion    Polymorphic variants of AСE and NOS3 genes correlated with ED, increased arterial wall stiffness, and the presence of subclinical changes in the arterial wall.

A leucopoietic-arterial axis underlying the link between ambient air pollution and cardiovascular disease in humans

AIMS

Air pollution [i.e. particulate matter with diameter <2.5 μm (PM2.5)] is a risk factor for major adverse cardiovascular events (MACE). While PM2.5 promotes leucopoiesis and atherosclerotic inflammation in experimental models, it is unknown whether this occurs in humans. We tested in humans (a) whether PM2.5 associates with higher leucopoietic tissue activity and arterial inflammation (ArtI), (ii) whether these associations persist after accounting for the effects of potential confounders including socioeconomics, traffic noise, and risk factors, and (iii) whether these tissue effects mediate the association between air pollution and MACE.

METHODS AND RESULTS

Individuals (N = 503) without cardiovascular disease (CVD) or active malignancy underwent 18 F-fluorodeoxyglucose positron emission tomography/computed tomography. Major adverse cardiovascular event was adjudicated over 5 years of follow-up. Leucopoietic tissue activity (in bone marrow and spleen) as well as ArtI were measured. Annual PM2.5 levels were assessed at each individual's home address. At baseline, higher PM2.5 associated with increased leucopoietic activity [standardized (95% CI): 0.129 (0.042, 0.215), P = 0.004] as well as ArtI [0.088 (0.006, 0.171), P = 0.036] after adjusting for CVD risk factors. Over a median 4.1 years, 40 individuals experienced MACE. PM2.5 exposure associated with MACE [Cox HR (95% CI): 1.404 (1.135, 1.737), P = 0.002], remaining significant after adjustment for CVD risk factors and other potential confounders. Mediation analysis demonstrated that increased leucopoietic activity and ArtI serially mediate the link between PM2.5 exposure and MACE.

CONCLUSIONS

Higher air pollution exposure associates with heightened leucopoietic activity and ArtI and independently predicts MACE through a biological pathway that includes higher leucopoietic activity and ArtI in series.

Evaluation of Plaque Characteristics and Inflammation Using Magnetic Resonance Imaging

Atherosclerosis is an inflammatory disease of large and medium-sized arteries, characterized by the growth of atherosclerotic lesions (plaques). These plaques often develop at inner curvatures of arteries, branchpoints, and bifurcations, where the endothelial wall shear stress is low and oscillatory. In conjunction with other processes such as lipid deposition, biomechanical factors lead to local vascular inflammation and plaque growth. There is also evidence that low and oscillatory shear stress contribute to arterial remodeling, entailing a loss in arterial elasticity and, therefore, an increased pulse-wave velocity. Although altered shear stress profiles, elasticity and inflammation are closely intertwined and critical for plaque growth, preclinical and clinical investigations for atherosclerosis mostly focus on the investigation of one of these parameters only due to the experimental limitations. However, cardiovascular magnetic resonance imaging (MRI) has been demonstrated to be a potent tool which can be used to provide insights into a large range of biological parameters in one experimental session. It enables the evaluation of the dynamic process of atherosclerotic lesion formation without the need for harmful radiation. Flow-sensitive MRI provides the assessment of hemodynamic parameters such as wall shear stress and pulse wave velocity which may replace invasive and radiation-based techniques for imaging of the vascular function and the characterization of early plaque development. In combination with inflammation imaging, the analyses and correlations of these parameters could not only significantly advance basic preclinical investigations of atherosclerotic lesion formation and progression, but also the diagnostic clinical evaluation for early identification of high-risk plaques, which are prone to rupture. In this review, we summarize the key applications of magnetic resonance imaging for the evaluation of plaque characteristics through flow sensitive and morphological measurements. The simultaneous measurements of functional and structural parameters will further preclinical research on atherosclerosis and has the potential to fundamentally improve the detection of inflammation and vulnerable plaques in patients.

Association Between Left Ventricular Noncompaction and Vigorous Physical Activity

BACKGROUND

Left ventricular (LV) hypertrabeculation fulfilling noncompaction cardiomyopathy criteria has been detected in athletes. However, the association between LV noncompaction (LVNC) phenotype and vigorous physical activity (VPA) in the general population is disputed.

OBJECTIVES

The aim of this study was to assess the relationship between LVNC phenotype on cardiac magnetic resonance (CMR) imaging and accelerometer-measured physical activity (PA) in a cohort of middle-aged nonathlete participants in the PESA (Progression of Early Subclinical Atherosclerosis) study.

METHODS

In PESA participants (n = 4,184 subjects free of cardiovascular disease), PA was measured by waist-secured accelerometers. CMR was performed in 705 subjects (mean age 48 ± 4 years, 16% women). VPA was recorded as total minutes per week. The study population was divided into 6 groups: no VPA and 5 sex-specific quintiles of VPA rate (Q1 to Q5). The Petersen criterion for LVNC was evaluated in all subjects undergoing CMR. For participants meeting this criterion (noncompacted-to-compacted ratio ≥2.3), 3 more restrictive LVNC criteria were also evaluated (Jacquier, Grothoff, and Stacey).

RESULTS

LVNC phenotype prevalence according to the Petersen criterion was significantly higher among participants in the highest VPA quintile (Q5 = 30.5%) than in participants with no VPA (14.2%). The Jacquier and Grothoff criteria were also more frequently fulfilled in participants in the highest VPA quintile (Jacquier Q5 = 27.4% vs. no VPA = 12.8% and Grothoff Q5 = 15.8% vs. no VPA = 7.1%). The prevalence of the systolic Stacey LVNC criterion was low (3.6%) and did not differ significantly between no VPA and Q5.

CONCLUSIONS

In a community-based study, VPA was associated with a higher prevalence of CMR-detected LVNC phenotype according to diverse established criteria. The association between VPA and LVNC phenotype was independent of LV volumes. According to these data, vigorous recreational PA should be considered as a possible but not uncommon determinant of LV hypertrabeculation in asymptomatic subjects.

Subclinical Atherosclerosis and Brain Metabolism in Middle-Aged Individuals: The PESA Study

BACKGROUND

Atherosclerosis has been linked to cognitive decline in late life; however, the impact of cardiovascular risk factors (CVRFs) and subclinical atherosclerosis on brain metabolism at earlier stages remains unexplored.

OBJECTIVES

This study sought to determine the association between brain metabolism, subclinical atherosclerosis, and CVRFs in middle-aged asymptomatic individuals.

METHODS

This study included 547 asymptomatic middle-aged participants (50 ± 4 years, 82% men) from the PESA (Progression of Early Subclinical Atherosclerosis) study with evidence of subclinical atherosclerosis. Participants underwent ¹⁸F-fluorodeoxyglucose (FDG)-positron emission tomography. Global brain FDG uptake and voxel-wise analyses were used to evaluate the associations of cerebral metabolism with CVRFs and atherosclerotic plaque burden in carotids and femorals assessed by 3-dimensional vascular ultrasound.

RESULTS

Global FDG uptake showed an inverse correlation with 30-year Framingham Risk Score (FRS) (β = -0.15, p < 0.001). This association was mainly driven by the presence of hypertension (d = 0.36, p < 0.001). Carotid plaque burden was inversely associated with global brain FDG uptake (β = -0.16, p < 0.001), even after adjusting for 30-year FRS. Voxel-wise approaches revealed that the brain areas most strongly affected by hypometabolism in association with 30-year FRS, hypertension, and carotid plaque burden were parietotemporal regions (angular, supramarginal, and inferior/middle temporal gyri) and the cingulate gyrus.

CONCLUSIONS

In asymptomatic middle-aged individuals, cardiovascular risk is associated with brain hypometabolism, with hypertension being the modifiable CVRF showing the strongest association. Subclinical carotid plaque burden is also linked to reduced brain metabolism independently of CVRFs. Cerebral areas showing hypometabolism include those known to be affected in dementia. These data reinforce the need to control CVRFs early in life in order to potentially reduce the brain's midlife vulnerability to future cognitive dysfunction.

Complement C5 Protein as a Marker of Subclinical Atherosclerosis

BACKGROUND

The mechanisms underlying early atherosclerotic plaque formation are not completely understood. Moreover, plasma biomarkers of subclinical atherosclerosis are lacking.

OBJECTIVES

The purpose of this study was to analyze the temporal and topologically resolved protein changes taking place in human aortas with early atherosclerosis to find new potential diagnostic and/or therapeutic targets.

METHODS

The protein composition of healthy aortas (media layer) or with early atheroma (fatty streak and fibrolipidic, media and intima layers) was analyzed by deep quantitative multiplexed proteomics. Further analysis was performed by Western blot, immunohistochemistry, real-time polymerase chain reaction, and enzyme-linked immunosorbent assay. Plasma levels of complement C5 were analyzed in relation to the presence of generalized (>2 plaques) or incipient (0 to 2 plaques) subclinical atherosclerosis in 2 independent clinical cohorts (PESA [Progression of Early Subclinical Atherosclerosis] [n = 360] and NEFRONA [National Observatory of Atherosclerosis in Nephrology] [n = 394]).

RESULTS

Proteins involved in lipid transport, complement system, immunoglobulin superfamily, and hemostasis are increased in early plaques. Components from the complement activation pathway were predominantly increased in the intima of fibrolipidic plaques. Among them, increased C5 protein levels were further confirmed by Western blot, enzyme-linked immunosorbent assay and immunohistochemistry, and associated with in situ complement activation. Plasma C5 was significantly increased in individuals with generalized subclinical atherosclerosis in both PESA and NEFRONA cohorts, independently of risk factors. Moreover, in the PESA study, C5 plasma levels positively correlated with global plaque volume and coronary calcification.

CONCLUSIONS

Activation of the complement system is a major alteration in early atherosclerotic plaques and is reflected by increased C5 plasma levels, which have promising value as a novel circulating biomarker of subclinical atherosclerosis.

Inflammation and cardiovascular disease: From mechanisms to therapeutics

Inflammation constitutes a complex, highly conserved cascade of molecular and cellular events. Inflammation has been labeled as “the fire within,” is highly regulated, and is critical to host defense and tissue repair. In general, inflammation is beneficial and has evolved to promote survival. However, inflammation can also be maladaptive when chronically activated and sustained, leading to progressive tissue injury and reduced survival. Examples of a maladaptive response include rheumatologic disease and atherosclerosis. Despite evidence gathered by Virchow over 100 years ago showing that inflammatory white cells play a role in atherogenesis, atherosclerosis was until recently viewed as a disease of passive cholesterol accumulation in the subendothelial space. This view has been supplanted by considerable basic scientific and clinical evidence demonstrating that every step of atherogenesis, from the development of endothelial cell dysfunction to foam cell formation, plaque formation and progression, and ultimately plaque rupture stemming from architectural instability, is driven by the cytokines, interleukins, and cellular constituents of the inflammatory response. Herein we provide an overview of the role of inflammation in atherosclerotic cardiovascular disease, discuss the predictive value of various biomarkers involved in inflammation, and summarize recent clinical trials that evaluated the capacity of various pharmacologic interventions to attenuate the intensity of inflammation and impact risk for acute cardiovascular events.

Reprogramming of bone marrow myeloid progenitor cells in patients with severe coronary artery disease

Atherosclerosis is the major cause of cardiovascular disease (CVD). Monocyte-derived macrophages are the most abundant immune cells in atherosclerotic plaques. In patients with atherosclerotic CVD, leukocytes have a hyperinflammatory phenotype. We hypothesize that immune cell reprogramming in these patients occurs at the level of myeloid progenitors. We included 13 patients with coronary artery disease due to severe atherosclerosis and 13 subjects without atherosclerosis in an exploratory study. Cytokine production capacity after ex vivo stimulation of peripheral blood mononuclear cells (MNCs) and bone marrow MNCs was higher in patients with atherosclerosis. In BM-MNCs this was associated with increased glycolysis and oxidative phosphorylation. The BM composition was skewed towards myelopoiesis and transcriptome analysis of HSC/GMP cell populations revealed enrichment of neutrophil- and monocyte-related pathways. These results show that in patients with atherosclerosis, activation of innate immune cells occurs at the level of myeloid progenitors, which adds exciting opportunities for novel treatment strategies.

Chronic inflammation, cardiometabolic diseases and effects of treatment: Psoriasis as a human model

Chronic inflammation in humans is associated with accelerated development of cardiometabolic diseases such as myocardial infarction, stroke, and diabetes. Strong evidence from animal models and human interventional trials including CANTOS (The Canakinumab Anti-inflammatory Thrombosis Outcome Study) suggests that targeting residual systemic inflammation in humans may impart a benefit in reducing cardiometabolic diseases. Diseases associated with heightened immune-activation and systemic inflammation including psoriasis, rheumatoid arthritis, systemic lupus erythematosus, and human immunodeficiency virus infection are associated with upwards of two to seven-fold risk of future adverse cardiac events even when adjusted for traditional risk factors. Over the past decade, psoriasis has been utilized as a human model to study inflammatory-induced cardiometabolic dysfunction and to better understand residual risk due to inflammation. The high prevalence and early onset of cardiovascular disease in psoriasis enhances the likelihood of discovering novel pathways in vascular disease progression when followed over time. Furthermore, the United States Food and Drug Administration approved treatments for psoriasis include cytokine inhibitors (anti-tumor necrosis factor, anti-interleukin 17, anti-interleukin 12/23) which while treating the skin disease provide a unique opportunity to characterize how treating the inflammatory pathways may impact atherosclerosis. Herein, we provide a review of chronic inflammation, cardiometabolic disease associations, and treatment effects with a focus on psoriasis as a human model of study.

Procedural recommendations of cardiac PET/CT imaging: standardization in inflammatory-, infective-, infiltrative-, and innervation (4Is)-related cardiovascular diseases: a joint collaboration of the EACVI and the EANM

With this document, we provide a standard for PET/(diagnostic) CT imaging procedures in cardiovascular diseases that are inflammatory, infective, infiltrative, or associated with dysfunctional innervation (4Is). This standard should be applied in clinical practice and integrated in clinical (multicenter) trials for optimal procedural standardization. A major focus is put on procedures using [¹⁸F]FDG, but 4Is PET radiopharmaceuticals beyond [¹⁸F]FDG are also described in this document. Whilst these novel tracers are currently mainly applied in early clinical trials, some multicenter trials are underway and we foresee in the near future their use in clinical care and inclusion in the clinical guidelines. Finally, PET/MR applications in 4Is cardiovascular diseases are also briefly described. Diagnosis and management of 4Is-related cardiovascular diseases are generally complex and often require a multidisciplinary approach by a team of experts. The new standards described herein should be applied when using PET/CT and PET/MR, within a multimodality imaging framework both in clinical practice and in clinical trials for 4Is cardiovascular indications.

PCSK9 and inflammation: role of shear stress, pro-inflammatory cytokines, and LOX-1

PCSK9 degrades low-density lipoprotein cholesterol (LDL) receptors and subsequently increases serum LDL cholesterol. Clinical trials show that inhibition of PCSK9 efficiently lowers LDL cholesterol levels and reduces cardiovascular events. PCSK9 inhibitors also reduce the extent of atherosclerosis. Recent studies show that PCSK9 is secreted by vascular endothelial cells, smooth muscle cells, and macrophages. PCSK9 induces secretion of pro-inflammatory cytokines in macrophages, liver cells, and in a variety of tissues. PCSK9 regulates toll-like receptor 4 expression and NF-κB activation as well as development of apoptosis and autophagy. PCSK9 also interacts with oxidized-LDL receptor-1 (LOX-1) in a mutually facilitative fashion. These observations suggest that PCSK9 is inter-twined with inflammation with implications in atherosclerosis and its major consequence-myocardial ischaemia. This relationship provides a basis for the use of PCSK9 inhibitors in prevention of atherosclerosis and related clinical events.

High-Frequency Ultrasound of Multiple Arterial Areas Reveals Increased Intima Media Thickness, Vessel Wall Appearance, and Atherosclerotic Plaques in Systemic Lupus Erythematosus

Introduction: Despite improved therapies and management, patients with systemic lupus erythematosus (SLE) still have increased risks of cerebrovascular and cardiovascular disease. High-frequency ultrasound (US) provides an opportunity to distinguish atherosclerosis from inflammation in the vessels. We hypothesized that an extended US protocol may add information regarding vascular affection in SLE.

Methods: Sixty patients (52 women, 8 men; mean age 43.2 ± 11.3 years) with SLE characterized by either lupus nephritis (LN; n = 20), antiphospholipid syndrome (APS; n = 20), or skin and joint involvement (n = 20) as well as matched healthy controls (n = 60) were included. Intima-media thickness (IMT), assessment of vessel walls, and plaque occurrence were recorded using high-frequency US (GE Logic E9) in common carotid, internal carotid, brachiocephalic, subclavian, axillary, common femoral, and proximal superficial femoral arteries as well as in the aortic arch.

Results: For the entire SLE group, IMT was increased in the internal carotid artery (0.52 ± 0.17 vs. 0.45 ± 0.09 mm, p = 0.004), the common femoral artery (0.57 ± 0.23 vs. 0.49 ± 0.11 mm, p < 0.01), the subclavian artery (0.58 ± 0.19 vs. 0.53 ± 0.13 mm, p = 0.02), and the aortic arch (1.21 ± 0.63 vs. 0.98 ± 0.25 mm, p = 0.002) compared to controls. These differences were primarily observed in the APS and LN groups compared to controls. Vessels with increased IMT ≥0.9 mm had a smooth, medium echogenic appearance in areas free of atherosclerotic plaques. Atherosclerotic plaques were detected in 15/60 patients (25%) as compared to 2/60 of the controls (3%). Plaques were predominantly (67%) located in the carotid bifurcation. Multivariate analysis revealed influence of age on IMT in all vessel areas. Furthermore, in the common femoral artery, sagittal abdominal diameter, diastolic blood pressure, and cholesterol all showed association with increased IMT. In the internal carotid artery, male sex and presence of Raynaud phenomenon influenced IMT.

Conclusion: Among SLE patients without presence of plaques, an extended US protocol revealed increased wall thickness with predominantly medium echogenic appearance highlighting possibly inflammation or early atherosclerosis. The appearance of vessel walls has not previously been studied in detail. An increased number of plaques were found in SLE compared to age- and sex-matched healthy controls. We found similar risk factors for increased IMT and occurrence of plaques, possibly indicating atherosclerotic mechanisms rather than inflammation.

Editor-in-Chief's Top Picks From 2019

Each week, I record audio summaries for every paper in JACC, as well as an issue summary. Although this process is quite time-consuming, I have become familiar with every paper that we publish. Thus, I have personally selected the top 100 papers (both Original Investigations and Review Articles, and an occasional Editorial Comment) from the distinct specialties each year. In addition to my personal choices, I have included papers that have been the most accessed or downloaded on our websites, as well as those selected by the JACC Editorial Board members. In order to present the full breadth of this important research in a consumable fashion, we will present these abstracts in this issue of JACC, as well as most of the central illustrations, with the realization that a magnifying glass will be be needed for appropriate visualization. The highlights comprise the following sections: Basic & Translational Research, Cardiac Failure & Myocarditis, Cardiomyopathies/Congenital & Genetics, Cardio-Oncology, Coronary Disease & Interventions, Hypertension, Imaging, Metabolic & Lipid Disorders, Neurovascular Disease & Dementia, Promoting Health & Prevention, Rhythm Disorders & Thromboembolism, Valvular Heart Disease, and Vascular Medicine (1-100).

68Ga-Prostate-Specific Membrane Antigen Uptake in Dissecting Abdominal Aortic Aneurysm

An 81-year-old man with prostate adenocarcinoma (Gleason 4 + 3 = 7) treated with brachytherapy and intermittent androgen deprivation therapy was referred for serial Ga-prostate-specific membrane antigen (PSMA-HBED-CC) PET/CT scans for rising prostate-specific antigen. Findings were suggestive of local prostatic recurrence and nodal metastases. An incidental PSMA-avid focus was noted in the anterior wall of an infrarenal aortic aneurysm, with a contrast-enhanced hyperdense region surrounded by a semilunar hypodense region anteriorly, consistent with enlarging dissecting thrombus. Increased PSMA avidity in atherosclerotic hypertensive lesions may relate to active plaque instability, indicating a need for further evaluation.

The Role of Carotid and Femoral Plaque Burden in the Diagnosis of Coronary Artery Disease

PURPOSE OF REVIEW

With limitations of cardiovascular disease risk stratification by traditional risk factors, the role of noninvasive imaging techniques, such as vascular ultrasound, has emerged as a prominent utility for decision-making in coronary artery disease. A review of current guidelines and contemporary approaches for carotid and femoral plaque assessment is needed to better inform the diagnosis, management, and treatment of atherosclerosis in clinical practice.

RECENT FINDINGS

The recent consensus-based guidelines for carotid plaque assessment in coronary artery disease have been established, supported by some outcomes-based research. Currently, there is a gap of evidence on the use of femoral ultrasound to detect atherosclerosis, as well as predict adverse cardiovascular outcomes. The quantification and characterization of individualized plaque burden are important to stratify risk in asymptomatic or symptomatic atherosclerosis patients. Standardized quantification guidelines, supported by further outcomes-based research, are required to assess disease severity and progression.

Novel Positron Emission Tomography Tracers for Imaging Vascular Inflammation

Purpose of Review

To provide a focused update on recent advances in positron emission tomography (PET) imaging in vascular inflammatory diseases and consider future directions in the field.

Recent Findings

While PET imaging with ¹⁸F-fluorodeoxyglucose (FDG) can provide a useful marker of disease activity in several vascular inflammatory diseases, including atherosclerosis and large-vessel vasculitis, this tracer lacks inflammatory cell specificity and is not a practical solution for imaging the coronary vasculature because of avid background myocardial signal. To overcome these limitations, research is ongoing to identify novel PET tracers that can more accurately track individual components of vascular immune responses. Use of these novel PET tracers could lead to a better understanding of underlying disease mechanisms and help inform the identification and stratification of patients for newly emerging immune-modulatory therapies.

Summary

Future research is needed to realise the true clinical translational value of PET imaging in vascular inflammatory diseases.

PET/MRI of atherosclerosis

Myocardial infarction and stroke are the most prevalent global causes of death. Each year 15 million people worldwide die due to myocardial infarction or stroke. Rupture of a vulnerable atherosclerotic plaque is the main underlying cause of stroke and myocardial infarction. Key features of a vulnerable plaque are inflammation, a large lipid-rich necrotic core (LRNC) with a thin or ruptured overlying fibrous cap, and intraplaque hemorrhage (IPH). Noninvasive imaging of these features could have a role in risk stratification of myocardial infarction and stroke and can potentially be utilized for treatment guidance and monitoring. The recent development of hybrid PET/MRI combining the superior soft tissue contrast of MRI with the opportunity to visualize specific plaque features using various radioactive tracers, paves the way for comprehensive plaque imaging. In this review, the use of hybrid PET/MRI for atherosclerotic plaque imaging in carotid and coronary arteries is discussed. The pros and cons of different hybrid PET/MRI systems are reviewed. The challenges in the development of PET/MRI and potential solutions are described. An overview of PET and MRI acquisition techniques for imaging of atherosclerosis including motion correction is provided, followed by a summary of vessel wall imaging PET/MRI studies in patients with carotid and coronary artery disease. Finally, the future of imaging of atherosclerosis with PET/MRI is discussed.

Perivascular Fat Density and Contrast Plaque Enhancement: Does a Correlation Exist?

BACKGROUND AND PURPOSE

Inflammatory changes in the fat tissue surrounding the coronary arteries have been associated with coronary artery disease and high-risk vulnerable plaques. Our aim was to investigate possible correlations between the presence and degree of perivascular fat density and a marker of vulnerable carotid plaque, namely contrast plaque enhancement on CTA.

MATERIALS AND METHODS

One-hundred patients (76 men, 24 women; mean age, 69 years) who underwent CT angiography for investigation of carotid artery stenosis were retrospectively analyzed. Contrast plaque enhancement and perivascular fat density were measured in 100 carotid arteries, and values were stratified according to symptomatic (ipsilateral-to-cerebrovascular symptoms)/asymptomatic status (carotid artery with the most severe degree of stenosis). Correlation coefficients (Pearson ρ product moment) were calculated between the contrast plaque enhancement and perivascular fat density. The differences among the correlation ρ values were calculated using the Fisher r-to-z transformation. Mann-Whitney analysis was also calculated to test differences between the groups.

RESULTS

There was a statistically significant positive correlation between contrast plaque enhancement and perivascular fat density (ρ value = 0.6582, P value = .001). The correlation was stronger for symptomatic rather than asymptomatic patients (ρ value = 0.7052, P value = .001 versus ρ value = 0.4092, P value = .001).

CONCLUSIONS

There was a positive association between perivascular fat density and contrast plaque enhancement on CTA. This correlation was stronger for symptomatic rather than asymptomatic patients. Our results suggest that perivascular fat density could be used as an indirect marker of plaque instability.

Activation of CXCR7 promotes endothelial repair and reduces the carotid atherosclerotic lesions through inhibition of pyroptosis signaling pathways

Endothelial injuries, including cell pyroptosis, are ongoing inflammatory processes with key roles in atherosclerosis development. Our previous report showed that the chemokine CXCL12 and its receptor CXCR7 are associated with the proliferation and angiogenesis of endothelial cells. Nevertheless, the mechanism underlying these effects on atherosclerotic lesions, especially on endothelial dysfunction, remains unknown. Here, we demonstrated that CXCR7 was upregulated in human carotid atherosclerotic plaques, apolipoprotein E knockout (ApoE^−/−) mice fed with a high‐fat diet (HFD), and oxidized lipopolysaccharide‐treated (ox‐LDL) human umbilical vein endothelial cells (HUVECs). Further, the activation of CXCR7 reversed ox‐LDL‐induced HUVEC dysfunction, such as migration, tube formation, and cell pyroptosis; all of these protective effects were alleviated by inhibition of CXCR7. The NOD‐like receptor family pyrin domain‐containing 3 (NLRP3) inflammasomes were also elevated in human carotid atherosclerotic plaques, ApoE^−/− mice fed with HFD, and ox‐LDL‐injured HUVECs by regulation of caspase‐1 and interleukin (IL)‐1β expression. The activation of CXCR7 by TC14012 led to a decrease in atherosclerotic lesions in ApoE^−/− mice fed with HFD. TC14012 also inhibited the expression of the NLRP3 inflammasome signaling pathway in vivo. In conclusion, our study suggests that CXCR7 plays an important role in regulating NLRP3 inflammasome‐modulated pyroptosis in HUVECs, providing a potential novel therapy for atherosclerosis.

Sustained Focal Vascular Inflammation Accelerates Atherosclerosis in Remote Arteries

OBJECTIVE

Evidence from preclinical and clinical studies has demonstrated that myocardial infarction promotes atherosclerosis progression. The impact of focal vascular inflammation on the progression and phenotype of remote atherosclerosis remains unknown. Approach and Results: We used a novel ApoE^-/- knockout mouse model of sustained arterial inflammation, initiated by mechanical injury in the abdominal aorta. Using serial in vivo molecular MRI and ex vivo histology and flow cytometry, we demonstrate that focal arterial inflammation triggered by aortic injury, accelerates atherosclerosis in the remote brachiocephalic artery. The brachiocephalic artery atheroma had distinct histological features including increased plaque size, plaque permeability, necrotic core to collagen ratio, infiltration of more inflammatory monocyte subsets, and reduced collagen content. We also found that arterial inflammation following focal vascular injury evoked a prolonged systemic inflammatory response manifested as a persistent increase in serum IL-6 (interleukin 6). Finally, we demonstrate that 2 therapeutic interventions-pravastatin and minocycline-had distinct anti-inflammatory effects at the plaque and systemic level.

CONCLUSIONS

We show for the first time that focal arterial inflammation in response to vascular injury enhances systemic vascular inflammation, accelerates remote atheroma progression and induces plaques more inflamed, lipid-rich, and collagen-poor in the absence of ischemic myocardial injury. This inflammatory cascade is modulated by pravastatin and minocycline treatments, which have anti-inflammatory effects at both plaque and systemic levels that mitigate atheroma progression.

Imaging of the vulnerable carotid plaque: Role of imaging techniques and a research agenda

OBJECTIVES

Atherothrombosis in the carotid arteries is a main cause of ischemic stroke and may depend on plaque propensity to complicate with rupture or erosion, in turn related to vulnerability features amenable to in vivo imaging. This would provide an opportunity for risk stratification and-potentially-local treatment of more vulnerable plaques. We here review current information on this topic.

METHODS

We systematically reviewed the literature for concepts derived from pathophysiologic, histopathologic, and clinical studies on imaging techniques attempting at identifying vulnerable carotid lesions.

RESULTS

Ultrasound, MRI, CT, and nuclear medicine-based techniques, alone or with multimodality approaches, all have a link to pathophysiology and describe different-potentially complementary-aspects of lesions prone to complications. There is also, however, a true paucity of head-to-head comparisons of such techniques for practical implementation of a thorough and cost-effective diagnostic strategy based on evaluation of outcomes. Especially in asymptomatic patients, major international societies leave wide margins of indecision in the advice to techniques guiding interventions to prevent atherothrombotic stroke.

CONCLUSIONS

To improve practical management of such patients-in addition to the patient's vulnerability for systemic reasons-a more precise identification of the vulnerable plaque is needed. A better definition of the diagnostic yield of each imaging approach in comparison with the others should be pursued for a cost-effective translation of the single techniques. Practical translation to guide future clinical practice should be based on improved knowledge of the specific pathophysiologic correlates and on a comparative modality approach, linked to subsequent stroke outcomes.

Multi-parameter characterization of atherosclerotic plaques based on optical coherence tomography, photoacoustic and viscoelasticity imaging

Detection of atherosclerotic plaque vulnerability is the critical step in prevention of acute coronary events. Fibrous cap thickness, lipid core size, and inflammation extent are three key parameters for assessing plaque vulnerability. Here, we report on multimodality imaging of mice aortic plaques using a system that integrates optical coherence tomography (OCT), photoacoustic imaging (PAI), and photoacoustic viscoelasticity imaging (PAVEI). The thickness of fibrous cap is accurately evaluated by OCT, and PAI helps to determine the distribution and size of lipid core. The mechanical properties of plaques are closely related to the plaque compositions and the content and distribution of macrophages, while PAVEI can characterize the plaque viscoelasticity through the phase delay of photoacoustic signal. Experimental results demonstrate that the OCT-PAI-PAVEI system can comprehensively characterize the three traits of atherosclerotic plaques, thereby identifying high-risk lesions.

Integrated cardiovascular assessment of atherosclerosis using PET/MRI

Atherosclerosis is a systemic inflammatory disease typified by the development of lipid-rich atheroma (plaques), the rupture of which are a major cause of myocardial infarction and stroke. Anatomical evaluation of the plaque considering only the degree of luminal stenosis overlooks features associated with vulnerable plaques, such as high-risk morphological features or pathophysiology, and hence risks missing vulnerable or ruptured non-stenotic plaques. Consequently, there has been interest in identifying these markers of vulnerability using either MRI for morphology, or positron emission tomography (PET) for physiological processes involved in atherogenesis. The advent of hybrid PET/MRI scanners offers the potential to combine the strengths of PET and MRI to allow comprehensive assessment of the atherosclerotic plaque. This review will discuss the principles and technical aspects of hybrid PET/MRI assessment of atherosclerosis, and consider how combining the complementary modalities of PET and MRI has already furthered our understanding of atherogenesis, advanced drug development, and how it may hold potential for clinical application.

Network Medicine: A Clinical Approach for Precision Medicine and Personalized Therapy in Coronary Heart Disease

Early identification of coronary atherosclerotic pathogenic mechanisms is useful for predicting the risk of coronary heart disease (CHD) and future cardiac events. Epigenome changes may clarify a significant fraction of this "missing hereditability", thus offering novel potential biomarkers for prevention and care of CHD. The rapidly growing disciplines of systems biology and network science are now poised to meet the fields of precision medicine and personalized therapy. Network medicine integrates standard clinical recording and non-invasive, advanced cardiac imaging tools with epigenetics into deep learning for in-depth CHD molecular phenotyping. This approach could potentially explore developing novel drugs from natural compounds (i.e. polyphenols, folic acid) and repurposing current drugs, such as statins and metformin. Several clinical trials have exploited epigenetic tags and epigenetic sensitive drugs both in primary and secondary prevention. Due to their stability in plasma and easiness of detection, many ongoing clinical trials are focused on the evaluation of circulating miRNAs (e.g. miR-8059 and miR-320a) in blood, in association with imaging parameters such as coronary calcifications and stenosis degree detected by coronary computed tomography angiography (CCTA), or functional parameters provided by FFR/CT and PET/CT. Although epigenetic modifications have also been prioritized through network based approaches, the whole set of molecular interactions (interactome) in CHD is still under investigation for primary prevention strategies.

Elevated circulating metalloproteinase 7 predicts recurrent cardiovascular events in patients with carotid stenosis: a prospective cohort study

BACKGROUND

Major adverse cardiovascular events are the main cause of morbidity and mortality over the long term in patients undergoing carotid endarterectomy. There are few reports assessing the prognostic value of markers of inflammation in relation to the risk of cardiovascular disease after carotid endarterectomy. Here, we aimed to determine whether matrix metalloproteinases (MMP-1, MMP-2, MMP-7, MMP-9 and MMP-10), tissue inhibitor of MMPs (TIMP-1) and in vivo inflammation studied by ¹⁸F-FDG-PET/CT predict recurrent cardiovascular events in patients with carotid stenosis who underwent endarterectomy.

METHODS

This prospective cohort study was carried out on 31 consecutive patients with symptomatic (23/31) or asymptomatic (8/31) severe (> 70%) carotid stenosis who were scheduled for carotid endarterectomy between July 2013 and March 2016. In addition, 26 healthy controls were included in the study. Plasma and serum samples were collected 2 days prior to surgery and tested for MMP-1, MMP-2, MMP-7, MMP-9, MMP-10, TIMP-1, high-density lipoprotein, low-density lipoprotein, high-sensitivity C-reactive protein and erythrocyte sedimentation rate. ¹⁸F-FDG-PET/CT focusing on several territories' vascular wall metabolism was performed on 29 of the patients because of no presurgical availability in 2 symptomatic patients. Histological and immunohistochemical studies were performed with antibodies targeting MMP-10, MMP-9, TIMP-1 and CD68.

RESULTS

The patients with carotid stenosis had significantly more circulating MMP-1, MMP-7 and MMP-10 than the healthy controls. Intraplaque TIMP-1 was correlated with its plasma level (r = 0.42 P = .02) and with ¹⁸F-FDG uptake (r = 0.38 P = .05). We did not find any correlation between circulating MMPs and in vivo carotid plaque metabolism assessed by ¹⁸F-FDG-PET. After a median follow-up of 1077 days, 4 cerebrovascular, 7 cardiovascular and 11 peripheral vascular events requiring hospitalization were registered. Circulating MMP-7 was capable of predicting events over and above the traditional risk factors (HR = 1.15 P = .006). When the model was associated with the variables of interest, the risk predicted by ¹⁸F-FDG-PET was not significant.

CONCLUSIONS

Circulating MMP-7 may represent a novel marker for recurrent cardiovascular events in patients with moderate to severe carotid stenosis. MMP-7 may reflect the atherosclerotic burden but not plaque inflammation in this specific vascular territory.

Clinical imaging of cardiovascular inflammation

Cardiovascular disease due to atherosclerosis is the number one cause of morbidity and mortality worldwide. In the past twenty years, compelling preclinical and clinical data have indicated that a maladaptive inflammatory response plays a crucial role in the development of atherosclerosis initiation and progression in the vasculature, all the way to the onset of life-threatening cardiovascular events. Furthermore, inflammation is key to heart and brain damage and healing after myocardial infarction or stroke. Recent evidence indicates that this interplay between the vasculature, organs target of ischemia and the immune system is mediated by the activation of hematopoietic organs (bone marrow and spleen). In this evolving landscape, non-invasive imaging is becoming more and more essential to support either mechanistic preclinical studies to investigate the role of inflammation in cardiovascular disease (CVD), or as a translational tool to quantify inflammation in the cardiovascular system and hematopoietic organs in patients. In this review paper, we will describe the clinical applications of non-invasive imaging to quantify inflammation in the vasculature, infarcted heart and brain, and hematopoietic organs in patients with cardiovascular disease, with specific focus on [18F]FDG PET and other novel inflammation-specific radiotracers. Furthermore, we will briefly describe the most recent clinical applications of other imaging techniques such as MRI, SPECT, CT, CEUS and OCT in this arena.

Atherosclerosis Immunoimaging by Positron Emission Tomography

The immune system's role in atherosclerosis has long been an important research topic and is increasingly investigated for therapeutic and diagnostic purposes. Therefore, noninvasive imaging of hematopoietic organs and immune cells will undoubtedly improve atherosclerosis phenotyping and serve as a monitoring method for immunotherapeutic treatments. Among the available imaging techniques, positron emission tomography's unique features make it an ideal tool to quantitatively image the immune response in the context of atherosclerosis and afford reliable readouts to guide medical interventions in cardiovascular disease. Here, we summarize the state of the art in the field of atherosclerosis positron emission tomography immunoimaging and provide an outlook on current and future applications.