G-Protein Coupled Receptor Targeting on Myeloid Cells in Atherosclerosis

Targeting immune cell recruitment in atherosclerosis

Atherosclerosis is the primary underlying cause of myocardial infarction and stroke. Atherosclerotic cardiovascular disease is characterized by a chronic inflammatory reaction in medium-to-large-sized arteries, with its onset and perpetuation driven by leukocytes infiltrating the subendothelial space. Activation of endothelial cells triggered by hyperlipidaemia and lipoprotein retention in the arterial intima initiates the accumulation of pro-inflammatory leukocytes in the arterial wall, fostering the progression of atherosclerosis. This inflammatory response is coordinated by an array of soluble mediators, namely cytokines and chemokines, that amplify inflammation both locally and systemically and are complemented by tissue-specific molecules that regulate the homing, adhesion and transmigration of leukocytes. Despite abundant evidence from mouse models, only a few therapies targeting leukocytes in atherosclerosis have been assessed in humans. The major challenges for the clinical translation of these therapies include the lack of tissue specificity and insufficient selectivity of inhibition strategies. In this Review, we discuss the latest research on receptor-ligand pairs and interactors that regulate leukocyte influx into the inflamed artery wall, primarily focusing on studies that used pharmacological interventions. We also discuss mechanisms that promote the resolution of inflammation and highlight how major findings from these research areas hold promise as potential therapeutic strategies for atherosclerotic cardiovascular disease.

Relationship between G protein level with left ventricular systolic function in children with acyanotic heart disease

Heart failure is a pediatric emergency caused by the heart's inability to adequately meet the body metabolic needs and the most common cause is congenital heart disease (CHD). The G protein is the most prominent family of membrane-bound protein known to act in major regulatory events of the cardiovascular system, one of which is heart failure. The aim of this study was to determine the level of G protein and its relationship with left ventricular systolic function in children with acyanotic CHD. A cross-sectional study was conducted in Dr. Zaionel Abidin Hospital, Banda Aceh, Indonesia. The patients aged 0 to 18 years and had acyanotic CHD diagnosis by echocardiography were included. Anthropometry measurement was performed according to standard WHO procedures and G protein level was measured using the ELISA method. The Chi-squared test was used to measure the relationship between G protein level and left ventricular systolic function. Out of a total of 38 children with acyanotic CHD, the mean level of G protein was 36.25 ng/mL and the mean of left ventricular systolic function was 73.1%. There was no relationship between G protein and left ventricular systolic function in children with acyanotic CHD. However, further study with a larger sample size and considering other variables are needed to confirm this finding.

Decoding the transcriptome of calcified atherosclerotic plaque at single-cell resolution

Atherogenesis involves an interplay of inflammation, tissue remodeling and cellular transdifferentiation (CTD), making it especially difficult to precisely delineate its pathophysiology. Here we use single-cell RNA sequencing and systems-biology approaches to analyze the transcriptional profiles of vascular smooth muscle cells (VSMCs) and endothelial cells (ECs) in calcified atherosclerotic core (AC) plaques and patient-matched proximal adjacent (PA) portions of carotid artery tissue from patients undergoing carotid endarterectomy. Our results reveal an anatomic distinction whereby PA cells express inflammatory mediators, while cells expressing matrix-secreting genes occupy a majority of the AC region. Systems biology analysis indicates that inflammation in PA ECs and VSMCs may be driven by TNFa signaling. Furthermore, we identify POSTN, SPP1 and IBSP in AC VSMCs, and ITLN1, SCX and S100A4 in AC ECs as possible candidate drivers of CTD in the atherosclerotic core. These results establish an anatomic framework for atherogenesis which forms the basis for exploration of a site-specific strategy for disruption of disease progression.

Single-cell RNA sequencing and systems biology are used to profile the human vascular cell populations in calcified atherosclerotic core plaques from carotid endarterectomy samples, showing an anatomic distinction between gene expression of inflammatory versus matrix-secreting factors.

Prognostic value of plasma adipokine chemerin in patients with coronary artery disease

Background

Adipokine chemerin was proven to be associated with coronary artery disease (CAD), but its prognostic implications in CAD remain unclear.

Methods

This study consists of two parts, one is a basic study and the other is a clinical cohort study. First, we investigated the differential expression of six adipokines in the atherosclerotic mice model compared to mice with milder degrees of atherosclerosis and mice without atherosclerosis using microarray data. We then examined the potential of chemerin as a diagnostic and prognostic indicator in a CAD cohort. A total of 152 patients were enrolled in our study, including 77 patients with angiographically proven CAD and 75 control subjects without cardiovascular disease. Plasma adipokine chemerin levels were measured in all patients, and major adverse cardiovascular events (MACEs) were followed up, including ischemic stroke, non-fatal myocardial infarction, revascularization, and cardiovascular death.

Results

In the aortas of atherosclerotic mice, chemerin expression was up-regulated compared to control mice. The plasma chemerin levels of CAD patients were higher than those of non-CAD patients (128.93 ± 37.06 vs. 109.85 ± 27.47 mmol/L, respectively, P < 0.001). High chemerin levels were an independent predictor of CAD (β = 2.702, 95% CI, 1.344–5.431, P = 0.001). We followed up with patients for a median duration of 5.5 years (3.9–5.6). The Kaplan–Meier curves showed that patients in the high chemerin group had a significantly higher risk of MACEs than the low chemerin group in patients with CAD (log-rank P = 0.003), not with non-CAD (Log-rank P = 0.120). Furthermore, Cox multivariate analysis revealed that high chemerin levels were an independent predictor of MACEs (HR 2.267; 95% CI, 1.139–4.515; P = 0.020). Finally, the cellular study showed that chemerin is predominantly expressed in PBMC-derived macrophages.

Conclusion

Plasma chemerin levels were increased in the CAD patients, and a high chemerin level increased the risk of MACEs in CAD patients.

Radiopharmaceuticals for PET and SPECT Imaging: A Literature Review over the Last Decade

Positron emission tomography (PET) uses radioactive tracers and enables the functional imaging of several metabolic processes, blood flow measurements, regional chemical composition, and/or chemical absorption. Depending on the targeted processes within the living organism, different tracers are used for various medical conditions, such as cancer, particular brain pathologies, cardiac events, and bone lesions, where the most commonly used tracers are radiolabeled with 18F (e.g., [18F]-FDG and NA [18F]). Oxygen-15 isotope is mostly involved in blood flow measurements, whereas a wide array of 11C-based compounds have also been developed for neuronal disorders according to the affected neuroreceptors, prostate cancer, and lung carcinomas. In contrast, the single-photon emission computed tomography (SPECT) technique uses gamma-emitting radioisotopes and can be used to diagnose strokes, seizures, bone illnesses, and infections by gauging the blood flow and radio distribution within tissues and organs. The radioisotopes typically used in SPECT imaging are iodine-123, technetium-99m, xenon-133, thallium-201, and indium-111. This systematic review article aims to clarify and disseminate the available scientific literature focused on PET/SPECT radiotracers and to provide an overview of the conducted research within the past decade, with an additional focus on the novel radiopharmaceuticals developed for medical imaging.

Key Chemokine Pathways in Atherosclerosis and Their Therapeutic Potential

The search to improve therapies to prevent or treat cardiovascular diseases (CVDs) rages on, as CVDs remain a leading cause of death worldwide. Here, the main cause of CVDs, atherosclerosis, and its prevention, take center stage. Chemokines and their receptors have long been known to play an important role in the pathophysiological development of atherosclerosis. Their role extends from the initiation to the progression, and even the potential regression of atherosclerotic lesions. These important regulators in atherosclerosis are therefore an obvious target in the development of therapeutic strategies. A plethora of preclinical studies have assessed various possibilities for targeting chemokine signaling via various approaches, including competitive ligands and microRNAs, which have shown promising results in ameliorating atherosclerosis. Developments in the field also include detailed imaging with tracers that target specific chemokine receptors. Lastly, clinical trials revealed the potential of various therapies but still require further investigation before commencing clinical use. Although there is still a lot to be learned and investigated, it is clear that chemokines and their receptors present attractive yet extremely complex therapeutic targets. Therefore, this review will serve to provide a general overview of the connection between various chemokines and their receptors with atherosclerosis. The different developments, including mouse models and clinical trials that tackle this complex interplay will also be explored.

Specialized Pro-Resolving Mediators Mitigate Cancer-Related Inflammation: Role of Tumor-Associated Macrophages and Therapeutic Opportunities

Inflammation is a fundamental physiological response orchestrated by innate immune cells to restore tissue homeostasis. Specialized pro-resolving mediators (SPMs) are involved in active resolution of inflammation but when inflammation is incomplete, chronic inflammation creates a favorable environment that fuels carcinogenesis and cancer progression. Conventional cancer therapy also strengthens cancer-related inflammation by inducing massive tumor cell death that activate surrounding immune-infiltrating cells such as tumor-associated macrophages (TAMs). Macrophages are key actors of both inflammation and its active resolution due to their plastic phenotype. In line with this high plasticity, macrophages can be hijacked by cancer cells to support tumor progression and immune escape, or therapy resistance. Impaired resolution of cancer-associated inflammation supported by TAMs may thus reinforces tumor progression. From this perspective, recent evidence suggests that stimulating macrophage's pro-resolving functions using SPMs can promote inflammation resolution in cancer and improve anticancer treatments. Thus, TAMs' re-education toward an antitumor phenotype by using SPMs opens a new line of attack in cancer treatment. Here, we review SPMs' anticancer capacities with special attention regarding their effects on TAMs. We further discuss how this new therapeutic approach could be envisioned in cancer therapy.

Periodontitis related to cardiovascular events and mortality: a long-time longitudinal study

OBJECTIVE

The present study assessed if individuals ≥ 60 years of age with periodontitis are more likely to develop stroke or ischemic heart diseases, or at a higher risk of death for 17 years.

MATERIAL AND METHODS

At baseline individuals ≥ 60 received a dental examination including a panoramic radiograph. Periodontitis was defined as having ≥ 30% sites with ≥ 5-mm distance from the cementoenamel junction to the marginal bone level. Medical records were annually reviewed from 2001 to 2018. Findings from the medical records identifying an ICD-10 code of stroke and ischemic heart diseases or death were registered.

RESULTS

Associations between periodontitis and incidence of ischemic heart disease were found in this 17-year follow-up study in all individuals 60-93 years (HR: 1.5, CI: 1.1-2.1, p = 0.017), in women (HR: 2.1, CI: 1.3-3.4, p = 0.002), and in individuals 78-96 years (HR: 1.7, CI: 1.0-2.6, p = 0.033). Periodontitis was associated with mortality in all individuals (HR: 1.4, CI: 1.2-1.8, p = 0.002), specifically in men (HR: 1.5, CI: 1.1-1.9, p = 0.006) or in ages 60-72 years (HR: 2.2, CI: 1.5-3.2, p = 0.000). Periodontitis was more prevalent among men (OR: 1.8, CI: 1.3-2.4, p = 0.000).

CONCLUSIONS

Individuals with periodontitis have an increased risk for future events of ischemic heart diseases and death.

CLINICAL RELEVANCE

Improving periodontal health in older individuals may reduce overall mortality and ischemic heart diseases. Both dental and medical professionals should be aware of the associations and ultimately cooperate.

Chemokine Receptor 5, a Double-Edged Sword in Metabolic Syndrome and Cardiovascular Disease

The key characteristic of cardiovascular disease (CVD) is endothelial dysfunction, which is likely the consequence of inflammation. It is well demonstrated that chemokines and their receptors play a crucial role in regulating inflammatory responses, and recently, much attention has been paid to chemokine receptor 5 (CCR5) and its ligands. For example, CCR5 aggravates the inflammatory response in adipose tissue by regulating macrophage recruitment and M1/M2 phenotype switch, thus causing insulin resistance and obesity. Inhibition of CCR5 expression reduces the aggregation of pro-atherogenic cytokines to the site of arterial injury. However, targeting CCR5 is not always effective, and emerging evidence has shown that CCR5 facilitates progenitor cell recruitment and promotes vascular endothelial cell repair. In this paper, we provide recent insights into the role of CCR5 and its ligands in metabolic syndrome as related to cardiovascular disease and the opportunities and roadblocks in targeting CCR5 and its ligands.

Current and novel radiopharmaceuticals for imaging cardiovascular inflammation

Cardiovascular disease (CVD) remains the leading cause of death worldwide despite advances in diagnostic technologies and treatment strategies. The underlying cause of most CVD is atherosclerosis, a chronic disease driven by inflammatory reactions. Atherosclerotic plaque rupture could cause arterial occlusion leading to ischemic tissue injuries such as myocardial infarction (MI) and stroke. Clinically, most imaging modalities are based on anatomy and provide limited information about the on-going molecular activities affecting the vulnerability of atherosclerotic lesion for risk stratification of patients. Thus, the ability to differentiate stable plaques from those that are vulnerable is an unmet clinical need. Of various imaging techniques, the radionuclide-based molecular imaging modalities including positron emission tomography and single-photon emission computerized tomography provide superior ability to noninvasively visualize molecular activities in vivo and may serve as a useful tool in tackling this challenge. Moreover, the well-established translational pathway of radiopharmaceuticals may also facilitate the translation of discoveries from benchtop to clinical investigation in contrast to other imaging modalities to fulfill the goal of precision medicine. The relationship between inflammation occurring within the plaque and its proneness to rupture has been well documented. Therefore, an active effort has been significantly devoted to develop radiopharmaceuticals specifically to measure CVD inflammatory status, and potentially elucidate those plaques which are prone to rupture. In the following review, molecular imaging of inflammatory biomarkers will be briefly discussed.

Type I interferons and endoplasmic reticulum stress in health and disease

Type I interferons (IFNs) comprise of pro-inflammatory cytokines created, as well as sensed, by all nucleated cells with the main objective of blocking pathogens-driven infections. Owing to this broad range of influence, type I IFNs also exhibit critical functions in many sterile inflammatory diseases and immunopathologies, especially those associated with endoplasmic reticulum (ER) stress-driven signaling pathways. Indeed, over the years accumulating evidence has indicated that the presence of ER stress can influence the production, or sensing of, type I IFNs induced by perturbations like pattern recognition receptor (PRR) agonists, infections (bacterial, viral or parasitic) or autoimmunity. In this article we discuss the link between type I IFNs and ER stress in various diseased contexts. We describe how ER stress regulates type I IFNs production or sensing, or how type I IFNs may induce ER stress, in various circumstances like microbial infections, autoimmunity, diabetes, cancer and other ER stress-related contexts.

The resolution of inflammation through omega-3 fatty acids in atherosclerosis, intimal hyperplasia, and vascular calcification

Omega-3 fatty acids serve as the substrate for the formation of a group of lipid mediators that mediate the resolution of inflammation. The cardiovascular inflammatory response in atherosclerosis and vascular injury is characterized by a failure in the resolution of inflammation, resulting in a chronic inflammatory response. The proresolving lipid mediator resolvin E1 (RvE1) is formed by enzymatic conversion of the omega-3 fatty acid eicosapentaenoic acid (EPA), and signals resolution of inflammation through its receptor ChemR23. Importantly, the resolution of cardiovascular inflammation is an active, multifactorial process that involves modulation of the immune response, direct actions on the vascular wall, as well as close interactions between macrophages and vascular smooth muscle cells. Promoting anti-atherogenic signalling through the stimulation of endogenous resolution of inflammation pathways may provide a novel therapeutic strategy in cardiovascular prevention.