Distinct functions of chemokine receptor axes in the atherogenic mobilization and recruitment of classical monocytes

Artery tertiary lymphoid organs in atherosclerosis: A review

Atherosclerosis (AS) is the common pathological basis for many cardiovascular diseases. Initial investigations into AS predominantly centered on endothelial immune responses associated with plaque formation. However, recent studies increasingly underscore the salutary immune modulation occurring on the aorta adventitia as the atheromatous plaque progresses. The immune responses extend from the intima of the vessel to the adventitia, and the artery tertiary lymphoid organ (ATLO) assumes a major immune role in advanced stages of AS, according to available studies conducted on ApoE-/- mice. In this review, we collate the history of studies on the participation of ATLOs in immunity to AS, detailing its structure, classification, cellular composition, and formation mechanisms. We elucidate the distinct roles of ATLO components in immune regulation, emphasizing unique features such as territorial organization, T cell-driven autoimmunity, and the T follicular helper-germinal center B cell axis, which distinguish ATLOs from conventional lymphoid responses. Furthermore, based on the latest research, we propose that ATLOs cooperate with the nervous system to regulate the progression of AS. Moreover, we highlight that aging has a great impact on the deterioration of AS and this impact is related to ATLOs. We conclude by suggesting that a focus on ATLOs is important for the clinical management of AS, and we offer a perspective for further research on ATLO and suggest whether it will be beneficial or detrimental to ATLOs.

Advancements in the study of short-chain fatty acids and their therapeutic effects on atherosclerosis

Atherosclerosis (AS) remains a leading cause of cardiovascular disease and mortality globally. This chronic condition is characterized by inflammation, lipid accumulation, and the deposition of cellular components within arterial walls. Emerging evidence has highlighted the multifaceted therapeutic potential of short-chain fatty acids (SCFAs) in mitigating AS progression. SCFAs have demonstrated anti-inflammatory properties and the ability to regulate immune responses, metabolic pathways, vascular integrity, and intestinal barrier function in animal models of AS. Consequently, SCFAs have garnered significant attention as a promising approach for the prevention and treatment of AS. However, further clinical trials and studies are necessary to fully elucidate the underlying mechanisms and effects of SCFAs. Additionally, different types of SCFAs may exert distinct impacts, necessitating more in-depth investigation into their specific roles and mechanisms. This review provides an overview of the diverse cellular mechanisms contributing to AS formation, as well as a discussion of the significance of SCFAs in AS pathogenesis and their multifaceted therapeutic potential. Nonetheless, additional research is warranted to comprehensively understand and harness the potential of various SCFAs in the context of AS.

Association of monocyte-to-high-density lipoprotein cholesterol ratio with peripheral artery disease and long-term mortality

BackgroundThis study aims to investigate the association of monocyte-to-high-density lipoprotein cholesterol ratio (MHR) with peripheral artery disease (PAD) and long-term mortality.MethodsData from the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2004 were analyzed, with mortality follow-up tracked via the National Death Index until December 31, 2019. Logistic regression was used to examine the relationship between MHR and PAD, while Cox proportional hazards regression assessed the association of MHR with mortality in individuals with PAD.ResultsA total of 6319 participants were included, among whom 550 were identified as having PAD. In weighted multivariate logistic regression analysis, participants in the third (odds ratio [OR]: 1.031, 95% confidence interval [CI]: 1.009-1.053, p = 0.007) and fourth (OR: 1.034, 95% CI: 1.011-1.057, p = 0.006) quartiles of MHR demonstrated significantly higher risks of PAD compared to those in the first quartile. Among PAD individuals, during a median follow-up period of 136 (71, 197) months, 422 deaths occurred. Higher MHR was associated with an increased risk of long-term mortality in females (hazard ratio [HR]: 1.695, 95% CI: 1.222-2.350, p = 0.002) but not in males (HR: 0.761, 95% CI: 0.554-1.044 p = 0.090).ConclusionsElevated MHR is independently associated with PAD among U.S. population. The association between MHR and long-term prognosis of PAD exhibits gender differences, with a significant relationship observed between elevated MHR and long-term mortality risk in females, but not in males.

Redefining Macrophage Heterogeneity in Atherosclerosis: A Focus on Possible Therapeutic Implications

Atherosclerosis is a lipid disorder where modified lipids (especially oxidized LDL) induce macrophage foam cell formation in the aorta. Its pathogenesis involves a continuum of persistent inflammation accompanied by dysregulated anti-inflammatory responses. Changes in the immune cell status due to differences in the lesional microenvironment are crucial in terms of plaque development, its progression, and plaque rupture. Ly6Chi monocytes generated through both medullary and extramedullary cascades act as one of the major sources of plaque macrophages and thereby foam cells. Both monocytes and monocyte-derived macrophages also participate in pathological events in atherosclerosis-associated multiple organ systems through inter-organ communications. For years, macrophage phenotypes M1 and M2 have been shown to perpetuate inflammatory and resolution responses; nevertheless, such a dualistic classification is too simplistic and contains severe drawbacks. As the lesion microenvironment is enriched with multiple mediators that possess the ability to activate macrophages to diverse phenotypes, it is obvious that such cells should demonstrate substantial heterogeneity. Considerable research in this regard has indicated the presence of additional macrophage phenotypes that are exclusive to atherosclerotic plaques, namely Mox, M4, Mhem, and M(Hb) type. Furthermore, although the concept of macrophage clusters has come to the fore in recent years with the evolution of high-dimensional techniques, classifications based on such 'OMICS' approaches require extensive functional validation as well as metabolic phenotyping. Bearing this in mind, the current review provides an overview of the status of different macrophage populations and their role during atherosclerosis and also outlines possible therapeutic implications.

Serum chemokines combined with multi-modal imaging to evaluate atherosclerotic plaque stability in patients undergoing carotid endarterectomy

Background

Although imaging tools are crucial in identifying features of atherosclerotic plaque, there remains a lack of consensus on the use of serological markers for assessing high-risk plaques.

Methods

Patients diagnosed with CAS who met the criteria for CEA were categorized as the operation group, while those without CAS were designated as the control group. Multi-modal imaging was conducted pre- and post-CEA to evaluate plaque features, such as the volume of calcification and LRNC, intra-plaque hemorrhage, and the degree of carotid stenosis. Serum chemokine levels were measured in both groups before CEA and on the 7th day post-surgery. Morphological features of carotid artery specimens were assessed using H&E and IHC (CD68 and α-SMA) staining to evaluate plaque stability.

Results

No significant differences in the degree of CAS between the operation and control groups. Among the operation group, 26 out of 52 patients were identified as vulnerable plaques. The volume of LRNC was significantly higher in vulnerable plaque, whereas the volume of calcification was significantly lower in vulnerable plaque compared to stable plaque confirmed by multi-modal imaging. Vulnerable plaque exhibited a thin fibrous cap covered an LRNC, intra-plaque hemorrhage, and macrophage infiltration. Stable plaque were characterized by small lipid cores covered by a thick fibrous cap, with minimal macrophage infiltration. Chemokine levels were significantly elevated in CAS patients compared to controls, and decreased significantly on the 7th day post-CEA. In patients with vulnerable plaque, lower levels of CX3CL1, CXCL12, CCL19, and CCL21, but higher levels of CCL2 and CCL5, were observed compared to patients with stable plaque. Correlation analysis further indicated that CX3CL1 and CXCL12 levels were positively associated with calcification volume. While CCL2 and CCL5 levels were positively associated, and CCL19 and CCL21 negatively associated, with LRNC volume. Multivariate analysis suggested that CXCL12 was an independent protective factor and LRNC volume as an independent risk factor for plaque vulnerability. The combination with multi-modal imaging and serological markers enhanced both the sensitivity (87.31%) and specificity (92.31%) in predicting plaque stability, with an AUC of 0.9001.

Conclusion

Combining multi-modal imaging with serological markers provides a more comprehensive evaluation of atherosclerotic plaque features.

Distinct inflammatory pathways shape atherosclerosis in different vascular beds

Studies suggest varying atherosclerotic cardiovascular disease (ASCVD) prevalence across arterial beds. Factors such as smoking expedite ASCVD progression in the abdominal aorta, while diabetes accelerates plaque development in lower limb arteries, and hypertension plays a significant role in ASCVD development in the coronary and carotid arteries. Moreover, superficial femoral atherosclerosis advances slower compared with atherosclerosis in coronary and carotid arteries. Furthermore, femoral atherosclerosis exhibits higher levels of ossification and calcification, but lower cholesterol concentrations compared with atherosclerotic lesions of other vascular beds. Such disparities exemplify the diverse progression of ASCVD across arterial beds, pointing towards differential mechanistic pathways in each vascular bed. Hence, this review summarizes current literature on immune-inflammatory mechanisms in various arterial beds in ASCVD to advance our understanding of this disease in an aging society with increased need of vascular bed and patient-specific treatment options.

Analysis and validation of biomarkers and immune cell infiltration profiles in unstable coronary atherosclerotic plaques using bioinformatics and machine learning

Introduction

Decreased stability of coronary atherosclerotic plaques correlates with a heightened risk of acute coronary syndrome (ACS). Thus, early diagnosis and treatment of unstable plaques are imperative in averting adverse cardiovascular events. This study aims to identify diagnostic biomarkers for unstable coronary atherosclerotic plaques and investigate the role of immune cell infiltration in their formation.

Methods

The datasets GSE163154 and GSE111782, obtained from the gene expression omnibus (GEO) database, were amalgamated for bioinformatics analysis, using the dataset GSE43292 as a test set. Sequentially, we performed principal component analysis (PCA), differential gene expression analysis, enrichment analysis, weighted gene co-expression network analysis (WGCNA), utilized a machine learning algorithm to screen key genes, conducted receiver operating characteristic (ROC) curve analysis and nomogram model to assess biomarker diagnostic efficacy, validated the biomarkers, and analyzed immune cell infiltration.

Results

In conclusion, enrichment analyses demonstrate that genes are significantly enriched in inflammatory and immune-related pathways. We identified HSPA2 and GEM as key genes and validated them experimentally. Significant differences existed in immune cell infiltration between subgroups. Additionally, HSPA2 and GEM showed significant associations with a wide range of immune cells.

Discussion

HSPA2 and GEM can function as diagnostic biomarkers for unstable coronary atherosclerotic plaques. In combination with immune cell infiltration analyses, our study provides new insights into the future study of unstable plaque occurrence and molecular mechanisms.

Hematopoietic PI3Kδ deficiency aggravates murine atherosclerosis through impairment of Tregs

Chronic activation of the adaptive immune system is a hallmark of atherosclerosis. As PI3Kδ is a key regulator of T and B cell differentiation and function, we hypothesized that alleviation of adaptive immunity by PI3Kδ inactivation may represent an attractive strategy counteracting atherogenesis. As expected, lack of hematopoietic PI3Kδ in atherosclerosis-prone Ldlr-/- mice resulted in lowered T and B cell numbers, CD4+ effector T cells, Th1 response, and immunoglobulin levels. However, despite markedly impaired peripheral pro-inflammatory Th1 cells and atheromatous CD4+ T cells, the unexpected net effect of hematopoietic PI3Kδ deficiency was aggravated vascular inflammation and atherosclerosis. Further analyses revealed that PI3Kδ deficiency impaired numbers, immunosuppressive functions, and stability of regulatory CD4+ T cells (Tregs), whereas macrophage biology remained largely unaffected. Adoptive transfer of wild-type Tregs fully restrained the atherosclerotic plaque burden in Ldlr-/- mice lacking hematopoietic PI3Kδ, whereas PI3Kδ-deficient Tregs failed to mitigate disease. Numbers of atheroprotective B-1 and pro-atherogenic B-2 cells as well as serum immunoglobulin levels remained unaffected by adoptively transferred wild-type Tregs. In conclusion, we demonstrate that hematopoietic PI3Kδ ablation promotes atherosclerosis. Mechanistically, we identified PI3Kδ signaling as a powerful driver of atheroprotective Treg responses, which outweigh PI3Kδ-driven pro-atherogenic effects of adaptive immune cells like Th1 cells.

Myeloid cannabinoid CB1 receptor deletion confers atheroprotection in male mice by reducing macrophage proliferation in a sex-dependent manner

AIMS

Although the cannabinoid CB1 receptor has been implicated in atherosclerosis, its cell-specific effects in this disease are not well understood. To address this, we generated a transgenic mouse model to study the role of myeloid CB1 signalling in atherosclerosis.

METHODS AND RESULTS

Here, we report that male mice with myeloid-specific Cnr1 deficiency on atherogenic background developed smaller lesions and necrotic cores than controls, while only minor genotype differences were observed in females. Male Cnr1-deficient mice showed reduced arterial monocyte recruitment and macrophage proliferation with less inflammatory phenotype. The sex-specific differences in proliferation were dependent on oestrogen receptor (ER)α-oestradiol signalling. Kinase activity profiling identified a CB1-dependent regulation of p53 and cyclin-dependent kinases. Transcriptomic profiling further revealed chromatin modifications, mRNA processing, and mitochondrial respiration among the key processes affected by CB1 signalling, which was supported by metabolic flux assays. Chronic administration of the peripherally restricted CB1 antagonist JD5037 inhibited plaque progression and macrophage proliferation, but only in male mice. Finally, CNR1 expression was detectable in human carotid endarterectomy plaques and inversely correlated with proliferation, oxidative metabolism, and inflammatory markers, suggesting a possible implication of CB1-dependent regulation in human pathophysiology.

CONCLUSION

Impaired macrophage CB1 signalling is atheroprotective by limiting their arterial recruitment, proliferation, and inflammatory reprogramming in male mice. The importance of macrophage CB1 signalling appears to be sex-dependent.

A Comprehensive Genetic and Bioinformatic Analysis Provides Evidence for the Engagement of COVID-19 GWAS-Significant Loci in the Molecular Mechanisms of Coronary Artery Disease and Stroke

Cardiovascular diseases (CVDs) significantly exacerbate the severity and mortality of COVID-19. We aimed to investigate whether GWAS-significant SNPs correlate with CVDs in severe COVID-19 patients. DNA samples from 199 patients with severe COVID-19 hospitalized in intensive care units were genotyped using probe-based PCR for 10 GWAS SNPs previously implicated in severe COVID-19 outcomes. SNPs rs17713054 SLC6A20-LZTFL1 (risk allele A, OR = 2.14, 95% CI 1.06–4.36, p = 0.03), rs12610495 DPP9 (risk allele G, OR = 1.69, 95% CI 1.02–2.81, p = 0.04), and rs7949972 ELF5 (risk allele T, OR = 2.57, 95% CI 1.43–4.61, p = 0.0009) were associated with increased risk of coronary artery disease (CAD). SNPs rs7949972 ELF5 (OR = 2.67, 95% CI 1.38–5.19, p = 0.003) and rs61882275 ELF5 (risk allele A, OR = 1.98, 95% CI 1.14–3.45, p = 0.01) were linked to a higher risk of cerebral stroke (CS). No associations were observed with AH. Bioinformatics analysis revealed the involvement of GWAS-significant loci in atherosclerosis, inflammation, oxidative stress, angiogenesis, and apoptosis, which provides evidence of their role in the molecular mechanisms of CVDs. This study provides novel insights into the associations between GWAS-identified SNPs and the risk of CAD and CS.

The Role of Bacterial Extracellular Membrane Nanovesicles in Atherosclerosis: Unraveling a Potential Trigger

PURPOSE OF REVIEW

In this review, we explore the intriguing and evolving connections between bacterial extracellular membrane nanovesicles (BEMNs) and atherosclerosis development, highlighting the evidence on molecular mechanisms by which BEMNs can promote the athero-inflammatory process that is central to the progression of atherosclerosis.

RECENT FINDINGS

Atherosclerosis is a chronic inflammatory disease primarily driven by metabolic and lifestyle factors; however, some studies have suggested that bacterial infections may contribute to the development of both atherogenesis and inflammation in atherosclerotic lesions. In particular, the participation of BEMNs in atherosclerosis pathogenesis has attracted special attention. We provide some general insights into how the immune system responds to potential threats such as BEMNs during the development of atherosclerosis. A comprehensive understanding of contribution of BEMNs to atherosclerosis pathogenesis may lead to the development of targeted interventions for the prevention and treatment of the disease.

Interaction between peripheral blood mononuclear cells and Trypanosoma cruzi-infected adipocytes: implications for treatment failure and induction of immunomodulatory mechanisms in adipose tissue

Background/Introduction

Adipose tissue (AT) has been highlighted as a promising reservoir of infection for viruses, bacteria and parasites. Among them is Trypanosoma cruzi, which causes Chagas disease. The recommended treatment for the disease in Brazil is Benznidazole (BZ). However, its efficacy may vary according to the stage of the disease, geographical origin, age, immune background of the host and sensitivity of the strains to the drug. In this context, AT may act as an ally for the parasite survival and persistence in the host and a barrier for BZ action. Therefore, we investigated the immunomodulation of T. cruzi-infected human AT in the presence of peripheral blood mononuclear cells (PBMC) where BZ treatment was added.

Methods

We performed indirect cultivation between T. cruzi-infected adipocytes, PBMC and the addition of BZ. After 72h of treatment, the supernatant was collected for cytokine, chemokine and adipokine assay. Infected adipocytes were removed to quantify T. cruzi DNA, and PBMC were removed for immunophenotyping.

Results

Our findings showed elevated secretion of interleukin (IL)-6, IL-2 and monocyte chemoattractant protein-1 (MCP-1/CCL2) in the AT+PBMC condition compared to the other controls. In contrast, there was a decrease in tumor necrosis factor (TNF) and IL-8/CXCL-8 in the groups with AT. We also found high adipsin secretion in PBMC+AT+T compared to the treated condition (PBMC+AT+T+BZ). Likewise, the expression of CD80+ and HLA-DR+ in CD14+ cells decreased in the presence of T. cruzi.

Discussion

Thus, our findings indicate that AT promotes up-regulation of inflammatory products such as IL-6, IL-2, and MCP-1/CCL2. However, adipogenic inducers may have triggered the downregulation of TNF and IL-8/CXCL8 through the peroxisome proliferator agonist gamma (PPAR-g) or receptor expression. On the other hand, the administration of BZ only managed to reduce inflammation in the microenvironment by decreasing adipsin in the infected culture conditions. Therefore, given the findings, we can see that AT is an ally of the parasite in evading the host's immune response and the pharmacological action of BZ.

Cardiovascular events risk in patients with systemic autoimmune diseases: a prognostic systematic review and meta-analysis

BACKGROUND

Chronic inflammation is considered a risk factor for the development of atherosclerosis and cardiovascular (CV) events. We seek to assess the risk of CV events in patients with Systemic autoimmune diseases (SAD), such as Systemic Lupus Erythematosus (SLE), Rheumatoid Arthritis (RA), Psoriasis (Ps) and Ankylosing Spondylitis (AS), compared with the general population.

METHODS AND RESULTS

A systematic search of MEDLINE from inception up to May 2021 was performed. Observational studies including individuals with and without autoimmune diseases (SLE, RA, Ps, AS), which reported a measure of association and variability for the effect of SAD on CV events, were included. The random effects meta-analysis was performed using the Hartung-Knapp-Sidik-Jonkman approach to obtain the pooled estimates. Cardiovascular Events including CV mortality, non-fatal myocardial infarction (MI), non-fatal stroke and coronary revascularization were the main outcomes evaluated. Fifty-four studies were selected, with a total of 24,107,072 participants. The presence of SAD was associated with an increased risk of CV mortality (HR 1.49 [95% CI 1.10-2.03]), non-fatal MI (HR 1.42 [95% CI 1.23-1.62]), and non-fatal stroke (HR 1.47 [95% CI 1.28-1.70]). RA, SLE, and Ps (particularly with arthritis) were significantly associated with a higher risk of MI and stroke. SAD was also associated with an increased risk of Major Adverse Cardiovascular Events (MACE) (HR 1.45 [95% CI 1.16-1.83]).

CONCLUSION

Patients with SAD present an increased risk of CV morbidity and mortality, which should be considered when establishing therapeutic strategies. These findings support the role of systemic inflammation in the development of atherosclerosis-driven disease.

Identification of a non-canonical chemokine-receptor pathway suppressing regulatory T cells to drive atherosclerosis

CCL17 is produced by conventional dendritic cells (cDCs), signals through CCR4 on regulatory T cells (Tregs), and drives atherosclerosis by suppressing Treg functions through yet undefined mechanisms. Here we show that cDCs from CCL17-deficient mice display a pro-tolerogenic phenotype and transcriptome that is not phenocopied in mice lacking its cognate receptor CCR4. In the plasma of CCL17-deficient mice, CCL3 was the only decreased cytokine/chemokine. We found that CCL17 signaled through CCR8 as an alternate high-affinity receptor, which induced CCL3 expression and suppressed Treg functions in the absence of CCR4. Genetic ablation of CCL3 and CCR8 in CD4+ T cells reduced CCL3 secretion, boosted FoxP3+ Treg numbers, and limited atherosclerosis. Conversely, CCL3 administration exacerbated atherosclerosis and restrained Treg differentiation. In symptomatic versus asymptomatic human carotid atheroma, CCL3 expression was increased, while FoxP3 expression was reduced. Together, we identified a non-canonical chemokine pathway whereby CCL17 interacts with CCR8 to yield a CCL3-dependent suppression of atheroprotective Tregs.

Protective role of perivascular adipose tissue in the cardiovascular system

This review provides an overview of the key role played by perivascular adipose tissue (PVAT) in the protection of cardiovascular health. PVAT is a specific type of adipose tissue that wraps around blood vessels and has recently emerged as a critical factor for maintenance of vascular health. Through a profound exploration of existing research, this review sheds light on the intricate structural composition and cellular origins of PVAT, with a particular emphasis on combining its regulatory functions for vascular tone, inflammation, oxidative stress, and endothelial function. The review then delves into the intricate mechanisms by which PVAT exerts its protective effects, including the secretion of diverse adipokines and manipulation of the renin-angiotensin complex. The review further examines the alterations in PVAT function and phenotype observed in several cardiovascular diseases, including atherosclerosis, hypertension, and heart failure. Recognizing the complex interactions of PVAT with the cardiovascular system is critical for pursuing breakthrough therapeutic strategies that can target cardiovascular disease. Therefore, this review aims to augment present understanding of the protective role of PVAT in cardiovascular health, with a special emphasis on elucidating potential mechanisms and paving the way for future research directions in this evolving field.

Central regulation of stress-evoked peripheral immune responses

Stress-linked psychiatric disorders, including anxiety and major depressive disorder, are associated with systemic inflammation. Recent studies have reported stress-induced alterations in haematopoiesis that result in monocytosis, neutrophilia, lymphocytopenia and, consequently, in the upregulation of pro-inflammatory processes in immunologically relevant peripheral tissues. There is now evidence that this peripheral inflammation contributes to the development of psychiatric symptoms as well as to common co-morbidities of psychiatric disorders such as metabolic syndrome and immunosuppression. Here, we review the specific brain and spinal regions, and the neuronal populations within them, that respond to stress and transmit signals to peripheral tissues via the autonomic nervous system or neuroendocrine pathways to influence immunological function. We comprehensively summarize studies that have employed retrograde tracing to define neurocircuits linking the brain to the bone marrow, spleen, gut, adipose tissue and liver. Moreover, we highlight studies that have used chemogenetic or optogenetic manipulation or intracerebroventricular administration of peptide hormones to control somatic immune responses. Collectively, this growing body of literature illustrates potential mechanisms through which stress signals are conveyed from the CNS to immune cells to regulate stress-relevant behaviours and comorbid pathophysiology.

Prevention by the CXCR2 antagonist SCH527123 of the calcification of porcine heart valve cusps implanted subcutaneously in rats

Introduction

Calcification is a main cause of bioprosthetic heart valves failure. It may be promoted by the inflammation developed in the glutaraldehyde (GA)-fixed cusps of the bioprosthesis. We tested the hypothesis that antagonizing the C-X-C chemokines receptor 2 (CXCR2) may prevent the calcification of GA-fixed porcine aortic valves.

Materiel and methods

Four-week-old Sprague Dawley males were transplanted with 2 aortic valve cusps isolated from independent pigs and implanted into the dorsal wall. Four groups of 6 rats were compared: rats transplanted with GA-free or GA-fixed cusps and rats transplanted with GA-fixed cusps and treated with 1 mg/kg/day SCH5217123 (a CXCR2 antagonist) intraperitoneally (IP) or subcutaneously (SC) around the xenograft, for 14 days. Then, rats underwent blood count before xenografts have been explanted for histology and biochemistry analyses.

Results

A strong calcification of the xenografts was induced by GA pre-incubation. However, we observed a significant decrease in this effect in rats treated with SCH527123 IP or SC. Implantation of GA-fixed cusps was associated with a significant increase in the white blood cell count, an effect that was significantly prevented by SCH527123. In addition, the expression of the CD3, CD68 and CXCR2 markers was reduced in the GA-fixed cusps explanted from rats treated with SCH527123 as compared to those explanted from non-treated rats.

Conclusion

The calcification of GA-fixed porcine aortic valve cusps implanted subcutaneously in rats was significantly prevented by antagonizing CXCR2 with SCH527123. This effect may partly result from an inhibition of the GA-induced infiltration of T-cells and macrophages into the xenograft.

IL8 of Takifugu rubripes is a chemokine that interacts with peripheral blood leukocytes and promotes antibacterial defense

Interleukin 8 (IL8) is a CXC chemokine that plays a crucial role on promoting inflammatory response and immune regulation. In teleost, IL8 can induce the migration and activation of immune cells. However, the biological functions of IL8 are still unknown in Takifugu rubripes. In this study, we examined the biological characteristics of TrIL8 in T. rubripes. TrIL8 is composed of 98 residues and contained a chemokine CXC domain. We found that the TrIL8 expression was detected in diverse organs and significantly increased by Vibrio harveyi or Edwardsiella tarda challenge. The recombinant TrIL8 (rTrIL8) exhibited significantly the binding capacities to 8 tested bacteria. In addition, rTrIL8 could bind to peripheral blood leukocytes (PBL), and increased the expression of immune gene, resistance to bacterial infection, respiratory burst, acid phosphatase activity, chemotactic activity, and phagocytic activity of PBL. In the presence of rTrIL8, T. rubripes was enhanced the resistance to V. harveyi infection. These results indicated that TrIL8 is a chemokine and involved in the activation of immune cells against bacterial infection in teleost.

Macrophage-to-endothelial cell crosstalk by the cholesterol metabolite 27HC promotes atherosclerosis in male mice

Hypercholesterolemia and vascular inflammation are key interconnected contributors to the pathogenesis of atherosclerosis. How hypercholesterolemia initiates vascular inflammation is poorly understood. Here we show in male mice that hypercholesterolemia-driven endothelial activation, monocyte recruitment and atherosclerotic lesion formation are promoted by a crosstalk between macrophages and endothelial cells mediated by the cholesterol metabolite 27-hydroxycholesterol (27HC). The pro-atherogenic actions of macrophage-derived 27HC require endothelial estrogen receptor alpha (ERα) and disassociation of the cytoplasmic scaffolding protein septin 11 from ERα, leading to extranuclear ERα- and septin 11-dependent activation of NF-κB. Furthermore, pharmacologic inhibition of cyp27a1, which generates 27HC, affords atheroprotection by reducing endothelial activation and monocyte recruitment. These findings demonstrate cell-to-cell communication by 27HC, and identify a major causal linkage between the hypercholesterolemia and vascular inflammation that partner to promote atherosclerosis. Interventions interrupting this linkage may provide the means to blunt vascular inflammation without impairing host defense to combat the risk of atherosclerotic cardiovascular disease that remains despite lipid-lowering therapies.

Control of the post-infarct immune microenvironment through biotherapeutic and biomaterial-based approaches

Ischemic heart failure (IHF) is a leading cause of morbidity and mortality worldwide, for which heart transplantation remains the only definitive treatment. IHF manifests from myocardial infarction (MI) that initiates tissue remodeling processes, mediated by mechanical changes in the tissue (loss of contractility, softening of the myocardium) that are interdependent with cellular mechanisms (cardiomyocyte death, inflammatory response). The early remodeling phase is characterized by robust inflammation that is necessary for tissue debridement and the initiation of repair processes. While later transition toward an immunoregenerative function is desirable, functional reorientation from an inflammatory to reparatory environment is often lacking, trapping the heart in a chronically inflamed state that perpetuates cardiomyocyte death, ventricular dilatation, excess fibrosis, and progressive IHF. Therapies can redirect the immune microenvironment, including biotherapeutic and biomaterial-based approaches. In this review, we outline these existing approaches, with a particular focus on the immunomodulatory effects of therapeutics (small molecule drugs, biomolecules, and cell or cell-derived products). Cardioprotective strategies, often focusing on immunosuppression, have shown promise in pre-clinical and clinical trials. However, immunoregenerative therapies are emerging that often benefit from exacerbating early inflammation. Biomaterials can be used to enhance these therapies as a result of their intrinsic immunomodulatory properties, parallel mechanisms of action (e.g., mechanical restraint), or by enabling cell or tissue-targeted delivery. We further discuss translatability and the continued progress of technologies and procedures that contribute to the bench-to-bedside development of these critically needed treatments.

Machine learning-based mRNA signature in early acute myocardial infarction patients: the perspective toward immunological, predictive, and personalized

Patients diagnosed with stable coronary artery disease (CAD) are at continued risk of experiencing acute myocardial infarction (AMI). This study aims to unravel the pivotal biomarkers and dynamic immune cell changes, from an immunological, predictive, and personalized viewpoint, by implementing a machine-learning approach and a composite bioinformatics strategy. Peripheral blood mRNA data from different datasets were analyzed, and CIBERSORT was used for deconvoluting human immune cell subtype expression matrices. Weighted gene co-expression network analysis (WGCNA) in single-cell and bulk transcriptome levels was conducted to explore possible biomarkers for AMI, with a particular emphasis on examining monocytes and their involvement in cell-cell communication. Unsupervised cluster analysis was performed to categorize AMI patients into different subtypes, and machine learning methods were employed to construct a comprehensive diagnostic model to predict the occurrence of early AMI. Finally, RT-qPCR on peripheral blood samples collected from patients validated the clinical utility of the machine learning-based mRNA signature and hub biomarkers. The study identified potential biomarkers for early AMI, including CLEC2D, TCN2, and CCR1, and found that monocytes may play a vital role in AMI samples. Differential analysis revealed that CCR1 and TCN2 exhibited elevated expression levels in early AMI compared to stable CAD. Machine learning methods showed that the glmBoost+Enet [alpha=0.9] model achieved high predictive accuracy in the training set, external validation sets, and clinical samples in our hospital. The study provided comprehensive insights into potential biomarkers and immune cell populations involved in the pathogenesis of early AMI. The identified biomarkers and the constructed comprehensive diagnostic model hold great promise for predicting the occurrence of early AMI and can serve as auxiliary diagnostic or predictive biomarkers.

Platelet versus plasma CXCL14, coronary artery disease, and clinical outcomes

Background

Platelets express CXCL14, while platelet-derived CXCL14 induces monocyte chemotaxis and exerts an angiostatic effect on endothelial cells.

Objectives

This study investigated both platelet surface-associated and circulating levels of CXCL14 in patients with heart disease and associations of this chemokine with myocardial function and outcomes in patients with coronary artery disease (CAD).

Methods

This prospective study enrolled 450 patients with symptomatic heart disease. Platelet surface-associated and plasma CXCL14 levels were analyzed. All patients were followed up for 360 days for a primary composite outcome consisting of all-cause mortality, myocardial infarction, and/or ischemic stroke. Secondary outcomes consisted of the single events of all-cause mortality or myocardial infarction.

Results

Baseline platelet-associated but not circulating CXCL14 levels were significantly lower in patients with chronic coronary syndrome (mean fluorescence intensity logarithmized, 1.35 ± 0.35) when compared to those with acute coronary syndrome (1.47 ± 0.38) and without CAD (1.51 ± 0.40). Platelet CXCL14 levels were significantly lower (1.37 ± 0.37 vs 1.48 ± 0.39) and circulating CXCL14 levels were significantly higher (lg, 2.88 ± 0.20 pg/mL vs 2.82 ± 0.26 pg/mL) in patients with normal baseline left ventricular ejection fraction (LVEF) when compared to those with impaired LVEF. Low baseline circulating CXCL14 (hazard ratio, 2.33; 1.00-5.46) but not platelet CXCL14 was associated with worse outcome in patients with CAD.

Conclusion

Platelet-associated and circulating CXCL14 levels show differential regulation in patients with and without CAD. Although platelet-associated CXCL14 increased and circulating CXCL14 decreased with impairment of LVEF, only lower circulating CXCL14 upon admission was associated with worse prognosis in patients with CAD.

Exosomal non-coding RNAs: Emerging therapeutic targets in atherosclerosis

Atherosclerosis is an LDL-driven and inflammatory disorder of the sub-endothelial space. Available data have proposed that various factors could affect atherosclerosis pathogenesis, including inflammation, oxidation of LDL particles, endothelial dysfunction, foam cell formation, proliferation, and migration of vascular smooth muscle cells (VSMCs). In addition, other research indicated that the crosstalk among atherosclerosis-induced cells is a crucial factor in modulating atherosclerosis. Extracellular vesicles arenanoparticleswith sizes ranging from 30-150 nm, playing an important role in various pathophysiological situations. Exosomes, asa form of extracellular vesicles, could affect the crosstalk between sub-endothelial cells. They can transport bioactive components like proteins, lipids, RNA, and DNA. As an important cargo in exosomes, noncoding RNAs (ncRNAs) including microRNAs, long noncoding RNAs, and circular RNAs could modulate cellular functions by regulating the transcription, epigenetic alteration, and translation. The current work aimed to investigate the underlying molecular mechanisms of exosomal ncRNA as well as their potential as a diagnostic biomarker and therapeutic target in atherosclerosis.

Transient increase in atherosclerotic plaque macrophage content following Streptococcus pneumoniae pneumonia in ApoE-deficient mice

Introduction

Despite epidemiological associations between community acquired pneumonia (CAP) and myocardial infarction, mechanisms that modify cardiovascular disease during CAP are not well defined. In particular, largely due to a lack of relevant experimental models, the effect of pneumonia on atherosclerotic plaques is unclear. We describe the development of a murine model of the commonest cause of CAP, Streptococcus pneumoniae pneumonia, on a background of established atherosclerosis. We go on to use our model to investigate the effects of pneumococcal pneumonia on atherosclerosis.

Methods

C57BL/6J and ApoE-/- mice were fed a high fat diet to promote atherosclerotic plaque formation. Mice were then infected with a range of S. pneumoniae serotypes (1, 4 or 14) with the aim of establishing a model to study atherosclerotic plaque evolution after pneumonia and bacteremia. Laser capture microdissection of plaque macrophages enabled transcriptomic analysis.

Results

Intratracheal instillation of S. pneumoniae in mice fed a cholate containing diet resulted in low survival rates following infection, suggestive of increased susceptibility to severe infection. Optimization steps resulted in a final model of male ApoE-/- mice fed a Western diet then infected by intranasal instillation of serotype 4 (TIGR4) S. pneumoniae followed by antibiotic administration. This protocol resulted in high rates of bacteremia (88.9%) and survival (88.5%). Pneumonia resulted in increased aortic sinus plaque macrophage content 2 weeks post pneumonia but not at 8 weeks, and no difference in plaque burden or other plaque vulnerability markers were found at either time point. Microarray and qPCR analysis of plaque macrophages identified downregulation of two E3 ubiquitin ligases, Huwe1 and Itch, following pneumonia. Treatment with atorvastatin failed to alter plaque macrophage content or other plaque features.

Discussion

Without antibiotics, ApoE-/- mice fed a high fat diet were highly susceptible to mortality following S. pneumoniae infection. The major infection associated change in plaque morphology was an early increase in plaque macrophages. Our results also hint at a role for the ubiquitin proteasome system in the response to pneumococcal infection in the plaque microenvironment.

Properties and fate of human mesenchymal stem cells upon miRNA let-7f-promoted recruitment to atherosclerotic plaques

AIMS

Atherosclerosis is a chronic inflammatory disease of the arteries leading to the formation of atheromatous plaques. Human mesenchymal stem cells (hMSCs) are recruited from the circulation into plaques where in response to their environment they adopt a phenotype with immunomodulatory properties. However, the mechanisms underlying hMSC function in these processes are unclear. Recently, we described that miRNA let-7f controls hMSC invasion guided by inflammatory cytokines and chemokines. Here, we investigated the role of let-7f in hMSC tropism to human atheromas and the effects of the plaque microenvironment on cell fate and release of soluble factors.

METHODS AND RESULTS

Incubation of hMSCs with LL-37, an antimicrobial peptide abundantly found in plaques, increased biosynthesis of let-7f and N-formyl peptide receptor 2 (FPR2), enabling chemotactic invasion of the cells towards LL-37, as determined by qRT-PCR, flow cytometry, and cell invasion assay analysis. In an Apoe-/- mouse model of atherosclerosis, circulating hMSCs preferentially adhered to athero-prone endothelium. This property was facilitated by elevated levels of let-7f in the hMSCs, as assayed by ex vivo artery perfusion and two-photon laser scanning microscopy. Exposure of hMSCs to homogenized human atheromatous plaque material considerably induced the production of various cytokines, chemokines, matrix metalloproteinases, and tissue inhibitors of metalloproteinases, as studied by PCR array and western blot analysis. Moreover, exposure to human plaque extracts elicited differentiation of hMSCs into cells of the myogenic lineage, suggesting a potentially plaque-stabilizing effect.

CONCLUSIONS

Our findings indicate that let-7f promotes hMSC tropism towards atheromas through the LL-37/FPR2 axis and demonstrate that hMSCs upon contact with human plaque environment develop a potentially athero-protective signature impacting the pathophysiology of atherosclerosis.

Expanding role of CXCR2 and therapeutic potential of CXCR2 antagonists in inflammatory diseases and cancers

C-X-C motif chemokine receptor 2 (CXCR2) is G protein-coupled receptor (GPCR) and plays important roles in various inflammatory diseases and cancers, including chronic obstructive pulmonary disease (COPD), atherosclerosis, asthma, and pancreatic cancer. Upregulation of CXCR2 is closely associated with the migration of neutrophils and monocytes. To date, many small-molecule CXCR2 antagonists have entered clinical trials, showing favorable safety and therapeutic effects. Hence, we provide an overview containing the discovery history, protein structure, signaling pathways, biological functions, structure-activity relationships and clinical significance of CXCR2 antagonists in inflammatory diseases and cancers. According to the latest development and recent clinical progress of CXCR2 small molecule antagonists, we speculated that CXCR2 can be used as a biomarker and a new target for diabetes and that CXCR2 antagonists may also attenuate lung injury in coronavirus disease 2019 (COVID-19).

Monocyte chemokine receptors as therapeutic targets in cardiovascular diseases

Chemokine receptors are fundamental in many processes related to cardiovascular diseases, such as monocyte migration to vessel walls, cell adhesion, and angiogenesis, among others. Even though many experimental studies have shown the utility of blocking these receptors or their ligands in the treatment of atherosclerosis, the findings in clinical research are still poor. Thus, in the current review we aimed to describe some promising results concerning the blockade of chemokine receptors as therapeutic targets in the treatment of cardiovascular diseases and also to discuss some challenges that need to be overcome before using these strategies in clinical practice.

Advances in immunotherapy modalities for atherosclerosis

Cardiovascular disease (CVD) is one of the leading causes of death worldwide. Atherosclerosis is the pathological basis of atherosclerotic cardiovascular disease (ASCVD). Atherosclerosis is now understood to be a long-term immune-mediated inflammatory condition brought on by a complicated chain of factors, including endothelial dysfunction, lipid deposits in the artery wall, and monocyte-derived macrophage infiltration, in which both innate immunity and adaptive immunity play an indispensable role. Recent studies have shown that atherosclerosis can be alleviated by inducing a protective immune response through certain auto-antigens or exogenous antigens. Some clinical trials have also demonstrated that atherosclerotic is associated with the presence of immune cells and immune factors in the body. Therefore, immunotherapy is expected to be a new preventive and curative measure for atherosclerosis. In this review, we provide a summary overview of recent progress in the research of immune mechanisms of atherosclerosis and targeted therapeutic pathways.

Atherosclerosis: The Involvement of Immunity, Cytokines and Cells in Pathogenesis, and Potential Novel Therapeutics

As a leading contributor to coronary artery disease (CAD) and stroke, atherosclerosis has become one of the major cardiovascular diseases (CVD) negatively impacting patients worldwide. The endothelial injury is considered to be the initial step of the development of atherosclerosis, resulting in immune cell migration and activation as well as inflammatory factor secretion, which further leads to acute and chronic inflammation. In addition, the inflammation and lipid accumulation at the lesions stimulate specific responses from different types of cells, contributing to the pathological progression of atherosclerosis. As a result, recent studies have focused on using molecular biological approaches such as gene editing and nanotechnology to mediate cellular response during atherosclerotic development for therapeutic purposes. In this review, we systematically discuss inflammatory pathogenesis during the development of atherosclerosis from a cellular level with a focus on the blood cells, including all types of immune cells, together with crucial cells within the blood vessel, such as smooth muscle cells and endothelial cells. In addition, the latest progression of molecular-cellular based therapy for atherosclerosis is also discussed. We hope this review article could be beneficial for the clinical management of atherosclerosis.

Functions and therapeutic interventions of non-coding RNAs associated with TLR signaling pathway in atherosclerosis

Nowadays, emerging data demonstrate that the toll-like receptor (TLR) signaling pathway plays an important role in the progression of inflammatory atherosclerosis. Indeed, dysregulated TLR signaling pathway could be a cornerstone of inflammation and atherosclerosis, which contributes to the development of cardiovascular diseases. It is interesting to note that this pathway is heavily controlled by several mechanisms, such as epigenetic factors in which the role of non-coding RNAs (ncRNAs), particularly microRNAs and long noncoding RNAs as well as circular RNAs in the pathogenesis of atherosclerosis has been well studied. Recent years have seen a significant surge in the amount of research exploring the interplay between ncRNAs and TLR signaling pathway downstream targets in the development of atherosclerosis; however, there is still considerable room for improvement in this field. The current study was designed to review underlying mechanisms of TLR signaling pathway and ncRNA interactions to shed light on therapeutic implications in patients with atherosclerosis.

The Role of the Coagulation System in Peripheral Arterial Disease: Interactions with the Arterial Wall and Its Vascular Microenvironment and Implications for Rational Therapies

Peripheral artery disease (PAD) is a clinical manifestation of atherosclerotic disease with a large-scale impact on the economy and global health. Despite the role played by platelets in the process of atherogenesis being well recognized, evidence has been increasing on the contribution of the coagulation system to the atherosclerosis formation and PAD development, with important repercussions for the therapeutic approach. Histopathological analysis and some clinical studies conducted on atherosclerotic plaques testify to the existence of different types of plaques. Likely, the role of coagulation in each specific type of plaque can be an important determinant in the histopathological composition of atherosclerosis and in its future stability. In this review, we analyze the molecular contribution of inflammation and the coagulation system on PAD pathogenesis, focusing on molecular similarities and differences between atherogenesis in PAD and coronary artery disease (CAD) and discussing the possible implications for current therapeutic strategies and future perspectives accounting for molecular inflammatory and coagulation targets. Understanding the role of cross-talking between coagulation and inflammation in atherosclerosis genesis and progression could help in choosing the right patients for future dual pathway inhibition strategies, where an antiplatelet agent is combined with an anticoagulant, whose role, despite pathophysiological premises and trials' results, is still under debate.

The balance between protective and pathogenic immune responses to pneumonia in the neonatal lung is enforced by gut microbiota

Although modern clinical practices such as cesarean sections and perinatal antibiotics have improved infant survival, treatment with broad-spectrum antibiotics alters intestinal microbiota and causes dysbiosis. Infants exposed to perinatal antibiotics have an increased likelihood of life-threatening infections, including pneumonia. Here, we investigated how the gut microbiota sculpt pulmonary immune responses, promoting recovery and resolution of infection in newborn rhesus macaques. Early-life antibiotic exposure interrupted the maturation of intestinal commensal bacteria and disrupted the developmental trajectory of the pulmonary immune system, as assessed by single-cell proteomic and transcriptomic analyses. Early-life antibiotic exposure rendered newborn macaques more susceptible to bacterial pneumonia, concurrent with increases in neutrophil senescence and hyperinflammation, broad inflammatory cytokine signaling, and macrophage dysfunction. This pathogenic reprogramming of pulmonary immunity was further reflected by a hyperinflammatory signature in all pulmonary immune cell subsets coupled with a global loss of tissue-protective, homeostatic pathways in the lungs of dysbiotic newborns. Fecal microbiota transfer was associated with partial correction of the broad immune maladaptations and protection against severe pneumonia. These data demonstrate the importance of intestinal microbiota in programming pulmonary immunity and support the idea that gut microbiota promote the balance between pathways driving tissue repair and inflammatory responses associated with clinical recovery from infection in infants. Our results highlight a potential role for microbial transfer for immune support in these at-risk infants.

A Common Variant at the 3'untranslated Region of the CCL7 Gene (rs17735770) Is Associated With Decreased Susceptibility to Coronary Heart Disease

Monocytes participate in the development of atherosclerosis through the action of cytokines and other inflammatory mediators. Among them, CCR2 and its ligands, CCL2 and CCL7 play an important role, so the main objective of this work was to determine whether genetic variants affecting their activity were associated with cardiovascular disease. A cohort of 519 patients that have suffered coronary events was analyzed under a propensity score-matching protocol selecting a homogeneous set of cases and controls, according to age, sex, smoking status, dyslipidemia, arterial hypertension and type 2 diabetes as risk factors. While dyslipidemia and arterial hypertension were more prevalent among patients with angina pectoris, current smoking status and elevated inflammatory markers, including total leukocyte and monocyte counts, were more likely associated with acute coronary events. Propensity score matching analysis, performed to eliminate the influence of these risk factors and highlight genetic modifiers, revealed that a single nucleotide variant, rs17735770 at the 3'untranslated region of the CCL7 gene transcript, was associated with decreased cardiovascular risk in a group represented mostly by men, with an average age of 57, and without significant differences in traditional risk factors. Furthermore, the presence of this variant altered the local mRNA structure encompassing a binding site for miR-23ab, resulting in increased translation of a reporter gene in a miR23 independent fashion. The rs17735770 genetic variant led to increased expression of CCL7, a potential antagonist of CCR2 at inflammatory sites, where it could play a meaningful role during the evolution of atherosclerosis.

The Role of CXC Chemokines in Cardiovascular Diseases

Cardiovascular disease (CVD) is a class of diseases with high disability and mortality rates. In the elderly population, the incidence of cardiovascular disease is increasing annually. Between 1990 and 2016, the age-standardised prevalence of CVD in China significantly increased by 14.7%, and the number of cardiovascular disease deaths increased from 2.51 million to 3.97 million. Much research has indicated that cardiovascular disease is closely related to inflammation, immunity, injury and repair. Chemokines, which induce directed chemotaxis of reactive cells, are divided into four subfamilies: CXC, CC, CX3C, and XC. As cytokines, CXC chemokines are similarly involved in inflammation, immunity, injury, and repair and play a role in many cardiovascular diseases, such as atherosclerosis, myocardial infarction, cardiac ischaemia-reperfusion injury, hypertension, aortic aneurysm, cardiac fibrosis, postcardiac rejection, and atrial fibrillation. Here, we explored the relationship between the chemokine CXC subset and cardiovascular disease and its mechanism of action with the goal of further understanding the onset of cardiovascular disease.

Targeting the CCL2-CCR2 axis for atheroprotection

Decades of research have established atherosclerosis as an inflammatory disease. Only recently though, clinical trials provided proof-of-concept evidence for the efficacy of anti-inflammatory strategies with respect to cardiovascular events, thus offering a new paradigm for lowering residual vascular risk. Efforts to target the inflammasome-interleukin-1β-interleukin-6 pathway have been highly successful, but inter-individual variations in drug response, a lack of reduction in all-cause mortality, and a higher rate of infections also highlight the need for a second generation of anti-inflammatory agents targeting atherosclerosis-specific immune mechanisms while minimizing systemic side effects. CC-motif chemokine ligand 2/monocyte-chemoattractant protein-1 (CCL2/MCP-1) orchestrates inflammatory monocyte trafficking between the bone marrow, circulation, and atherosclerotic plaques by binding to its cognate receptor CCR2. Adding to a strong body of data from experimental atherosclerosis models, a coherent series of recent large-scale genetic and observational epidemiological studies along with data from human atherosclerotic plaques highlight the relevance and therapeutic potential of the CCL2-CCR2 axis in human atherosclerosis. Here, we summarize experimental and human data pinpointing the CCL2-CCR2 pathway as an emerging drug target in cardiovascular disease. Furthermore, we contextualize previous efforts to interfere with this pathway, scrutinize approaches of ligand targeting vs. receptor targeting, and discuss possible pathway-intrinsic opportunities and challenges related to pharmacological targeting of the CCL2-CCR2 axis in human atherosclerotic disease.

Pathophysiology of Atherosclerosis

Atherosclerosis is the main risk factor for cardiovascular disease (CVD), which is the leading cause of mortality worldwide. Atherosclerosis is initiated by endothelium activation and, followed by a cascade of events (accumulation of lipids, fibrous elements, and calcification), triggers the vessel narrowing and activation of inflammatory pathways. The resultant atheroma plaque, along with these processes, results in cardiovascular complications. This review focuses on the different stages of atherosclerosis development, ranging from endothelial dysfunction to plaque rupture. In addition, the post-transcriptional regulation and modulation of atheroma plaque by microRNAs and lncRNAs, the role of microbiota, and the importance of sex as a crucial risk factor in atherosclerosis are covered here in order to provide a global view of the disease.

Role of Distinct Macrophage Populations in the Development of Heart Failure in Macrophage Activation Syndrome

Macrophage activation syndrome (MAS) is one of the few entities in rheumatology with the potential to quickly cause multiple organ failure and loss of life, and as such, requires urgent clinical intervention. It has a broad symptomatology, depending on the organs it affects. One especially dangerous aspect of MAS's course of illness is myocarditis leading to acute heart failure and possibly death. Research in recent years has proved that macrophages settled in different organs are not a homogenous group, with particular populations differing in both structure and function. Within the heart, we can determine two major groups, based on the presence of the C-C 2 chemokine receptor (CCR2): CCR2+ and CCR2-. There are a number of studies describing their function and the changes in the population makeup between normal conditions and different illnesses; however, to our knowledge, there has not been one touching on the matter of changes occurring in the populations of heart macrophages during MAS and their possible consequences. This review summarizes the most recent knowledge on heart macrophages, the influence of select cytokines (those particularly significant in the development of MAS) on their activity, and both the immediate and long-term consequences of changes in the makeup of specific macrophage populations-especially the loss of CCR2- cells that are responsible for regenerative processes, as well as the substitution of tissue macrophages by the highly proinflammatory CCR2+ macrophages originating from circulating monocytes. Understanding the significance of these processes may lead to new discoveries that could improve the therapeutic methods in the treatment of MAS.

Therapeutic strategies targeting inflammation and immunity in atherosclerosis: how to proceed?

Atherosclerosis is a chronic inflammatory disease of the arterial wall, characterized by the formation of plaques containing lipid, connective tissue and immune cells in the intima of large and medium-sized arteries. Over the past three decades, a substantial reduction in cardiovascular mortality has been achieved largely through LDL-cholesterol-lowering regimes and therapies targeting other traditional risk factors for cardiovascular disease, such as hypertension, smoking, diabetes mellitus and obesity. However, the overall benefits of targeting these risk factors have stagnated, and a huge global burden of cardiovascular disease remains. The indispensable role of immunological components in the establishment and chronicity of atherosclerosis has come to the forefront as a clinical target, with proof-of-principle studies demonstrating the benefit and challenges of targeting inflammation and the immune system in cardiovascular disease. In this Review, we provide an overview of the role of the immune system in atherosclerosis by discussing findings from preclinical research and clinical trials. We also identify important challenges that need to be addressed to advance the field and for successful clinical translation, including patient selection, identification of responders and non-responders to immunotherapies, implementation of patient immunophenotyping and potential surrogate end points for vascular inflammation. Finally, we provide strategic guidance for the translation of novel targets of immunotherapy into improvements in patient outcomes.

In this Review, the authors provide an overview of the immune cells involved in atherosclerosis, discuss preclinical research and published and ongoing clinical trials assessing the therapeutic potential of targeting the immune system in atherosclerosis, highlight emerging therapeutic targets from preclinical studies and identify challenges for successful clinical translation.

Inflammation is an important component of the pathophysiology of cardiovascular disease; an imbalance between pro-inflammatory and anti-inflammatory processes drives chronic inflammation and the formation of atherosclerotic plaques in the vessel wall.

Clinical trials assessing canakinumab and colchicine therapies in atherosclerotic cardiovascular disease have provided proof-of-principle of the benefits associated with therapeutic targeting of the immune system in atherosclerosis.

The immunosuppressive adverse effects associated with the systemic use of anti-inflammatory drugs can be minimized through targeted delivery of anti-inflammatory drugs to the atherosclerotic plaque, defining the window of opportunity for treatment and identifying more specific targets for cardiovascular inflammation.

Implementing immunophenotyping in clinical trials in patients with atherosclerotic cardiovascular disease will allow the identification of immune signatures and the selection of patients with the highest probability of deriving benefit from a specific therapy.

Clinical stratification via novel risk factors and discovery of new surrogate markers of vascular inflammation are crucial for identifying new immunotherapeutic targets and their successful translation into the clinic.

Where the Action Is-Leukocyte Recruitment in Atherosclerosis

Atherosclerosis is the leading cause of death worldwide and leukocyte recruitment is a key element of this phenomenon, thus allowing immune cells to enter the arterial wall. There, in concert with accumulating lipids, the invading leukocytes trigger a plethora of inflammatory responses which promote the influx of additional leukocytes and lead to the continued growth of atherosclerotic plaques. The recruitment process follows a precise scheme of tethering, rolling, firm arrest, crawling and transmigration and involves multiple cellular and subcellular players. This review aims to provide a comprehensive up-to-date insight into the process of leukocyte recruitment relevant to atherosclerosis, each from the perspective of endothelial cells, monocytes and macrophages, neutrophils, T lymphocytes and platelets. In addition, therapeutic options targeting leukocyte recruitment into atherosclerotic lesions-or potentially arising from the growing body of insights into its precise mechanisms-are highlighted.

The Role of Chemokines in Cardiovascular Diseases and the Therapeutic Effect of Curcumin on CXCL8 and CCL2 as Pathological Chemokines in Atherosclerosis

Curcumin, as a vegetative flavonoid, has a protective and therapeutic role in various adverse states such as oxidative stress and inflammation. Remedial properties of this component have been reported in the different chronic diseases including cancers (myeloma, pancreatic, breast, colorectal), vitiligo, psoriasis, neuropathic pains, inflammatory disorders (osteoarthritis, uveitis, ulcerative colitis, Alzheimer), cardiovascular conditions, and diabetes.Cardiovascular disorders include atherosclerosis and various manifestations of atherosclerosis such as stroke, and myocardial infarction (MI) is the leading cause of mortality globally. Studies have shown varying expressions of inflammatory and non-inflammatory chemokines and chemokine receptors in cardiovascular disease, which have been highlighted first in this review. The alteration in chemokines secretion and chemokine receptors has an essential role in the pathophysiology of cardiovascular disease. Chemokines as cytokines with low molecular weight (8-12 kDa) mediate white blood cell (WBC) chemotactic reactions, vascular cell migration, and proliferation that induce endothelial dysfunction, atherogenesis, and cardiac hypertrophy.Several studies reported that curcumin could be advantageous in the attenuation of cardiovascular diseases via anti-inflammatory effects and redress of chemokine secretion and chemokine receptors. We present these studies with a focus on two chemokines: CXCL8 (IL-8) and CCL2 (chemoattractant protein 1 or MCP-1). Future research will further elucidate the precise potential of curcumin on chemokines in the adjustment of cardiovascular system activity or curcumin chemokine-based therapies.

The potential targets in immunotherapy of atherosclerosis

Cardiovascular disease is the most common cause of death, which has the highest mortality rate worldwide. Although a diverse range of inflammatory diseases can affect the cardiovascular system, however, heart failure and stroke occur due to atherosclerosis. Atherosclerosis is a chronic autoinflammatory disease of small to large vessels in which different immune mediators are involved in lipid plaque formation and inflammatory vascular remodeling process. A better understanding of the pathophysiology of atherosclerosis may lead to uncovering immunomodulatory therapies. Despite present diagnostic and therapeutic methods, the lack of immunotherapy in the prevention and treatment of atherosclerosis is perceptible. In this review, we will discuss the promising immunological-based therapeutics and novel preventive approaches for atherosclerosis. This study could provide new insights into a better perception of targeted therapeutic pathways and biological therapies.

Matrix metalloproteinase-2 on activated platelets triggers endothelial PAR-1 initiating atherosclerosis

AIMS 

Platelets participate in atherogenesis with mechanisms not yet fully clarified. Vascular wall MMP-2 is involved in the arterial remodelling accompanying atherosclerosis. Platelets contain and release MMP-2 but no informations are available on its role in atherosclerotic lesion formation.

METHODS AND RESULTS 

We generated double knockout mice lacking the LDL receptor and MMP-2 only in circulating blood cells showing that they develop significantly lesser femoral intima thickening after photochemical-induced arterial damage and atherosclerotic lesions in the aorta, measured by the en face method, after 4 months of atherogenic diet. Moreover, repeated transfusions of autologous-activated platelets in LDLR-/- mice on atherogenic diet significantly enhanced the extension of aortic atherosclerotic lesions while transfusion of activated platelets from MMP-2-/- mice did not. In vitro coincubation studies showed that platelet-derived MMP-2 plays a pivotal role in the development and progression of atherosclerosis through a complex cross-talk between activated platelets, monocyte/macrophages, and endothelial cells. Translational studies in patients with CAD and chronic HIV infection showed that platelet surface expression of MMP-2 highly significantly correlated with the degree of carotid artery stenosis.

CONCLUSION 

We show a previously unknown mechanism of the pathway through which platelets expressing MMP-2 trigger the initial phases of atherosclerosis and provide a mechanism showing that they activate endothelial PAR-1 triggering endothelial p38MAPK signalling and the expression of adhesion molecules. The development of drugs blocking selectively platelet MMP-2 or its expression may represent a new approach to the prevention of atherosclerosis.

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.

Immunotherapy and cardiovascular diseases (CVD): novel avenues for immunotherapeutic approaches

As current therapies for cardiovascular disease (CVD), predominantly based on lipid lowering, still face an unacceptable residual risk, novel treatment strategies are being explored. Besides lipids, inflammatory processes play a major role in the pathogenesis of atherosclerosis, the underlying cause of the majority of CVD. The first clinical trials targeting the interleukin-1β-inflammasome axis have shown that targeting this pathway is successful in reducing cardiovascular events but did not decrease overall CVD mortality. Hence, novel and improved immunotherapeutics to treat CVD are being awaited. In this review we highlight novel immunotherapeutic approaches in CVD as well as future challenges ahead.

Targeting the chemokine network in atherosclerosis

Chemokines and their receptors represent a potential target for immunotherapy in chronic inflammation. They comprise a large family of cytokines with chemotactic activity, and their cognate receptors are expressed on all cells of the body. This network dictates leukocyte recruitment and activation, angiogenesis, cell proliferation and maturation. Dysregulation of chemokine and chemokine receptor expression as well as function participates in many pathologies including cancer, autoimmune diseases and chronic inflammation. In atherosclerosis, a lipid-driven chronic inflammation of middle-sized and large arteries, chemokines and their receptors participates in almost all stages of the disease from initiation of fatty streaks to mature atherosclerotic plaque formation. Atherosclerosis and its complications are the main driver of mortality and morbidity in cardiovascular diseases (CVD). Hence, exploring new fields of therapeutic targeting of atherosclerosis is of key importance. This review gives an overview of the recent advances on the role of key chemokines and chemokine receptors in atherosclerosis, addresses chemokine-based biomarkers at biochemical, imaging and genetic level in human studies, and highlights the clinial trials targeting atherosclerosis.

Imaging and Targeting Coronary Artery Inflammation

Significance: Coronary artery disease (CAD) continues to be a leading cause of morbidity and mortality across the world despite significant progress in the prevention, diagnosis, and treatment of atherosclerotic disease. Recent Advances: The focus of the cardiovascular community has shifted toward seeking a better understanding of the inflammatory mechanisms driving residual CAD risk that is not modulated by current therapies. Significant progress has been achieved in revealing both proinflammatory and anti-inflammatory mechanisms, and how shift of the balance in favor of the former can drive the development of disease. Critical Issues: Advances in the noninvasive detection of coronary artery inflammation have been forthcoming. These advances include multiple imaging modalities, with novel applications of computed tomography both with and without positron emission tomography, and experimental ultrasound techniques. These advances will enable better selection of patients for anti-inflammatory treatments and assessment of treatment response. The rapid advancement in pharmaceutical design has enabled the production of specific antibodies against inflammatory pathways of atherosclerosis, with modest success to date. The pursuit of demonstrating the efficacy and safety of novel anti-inflammatory and/or proinflammatory resolution therapies for atherosclerotic CAD has become a major focus. Future Directions: This review seeks to provide an update of the latest evidence of all three of these highly related but disparate areas of inquiry: Our current understanding of the key mechanisms by which inflammation contributes to coronary artery atherosclerosis, the evidence for noninvasive assessment of coronary artery inflammation, and finally, the evidence for targeted therapies to treat coronary inflammation for the reduction of CAD risk. Antioxid. Redox Signal. 34, 1217-1243.

Monocyte-Chemoattractant Protein-1 Levels in Human Atherosclerotic Lesions Associate With Plaque Vulnerability

[Figure: see text].

Role of myeloid-derived chemokine CCL5/RANTES at an early stage of atherosclerosis

One of the hallmarks of atherosclerosis is ongoing accumulation of macrophages in the artery intima beginning at disease onset. Monocyte recruitment contributes to increasing macrophage abundance at early stages of atherosclerosis. Although the chemokine CCL5 (RANTES) has been studied in atherosclerosis, its role in the recruitment of monocytes to early lesions has not been elucidated. We show that expression of Ccl5 mRNA, as well as other ligands of the CCR5 receptor (Ccl3 and Ccl4), is induced in the aortic intima of Ldlr^-/- mice 3 weeks after the initiation of cholesterol-rich diet (CRD)-induced hypercholesterolemia. En face immunostaining revealed that CCL5 protein expression is also upregulated at 3 weeks of CRD. Blockade of CCR5 significantly reduced monocyte recruitment to 3-week lesions, suggesting that chemokine signaling through CCR5 is critical. However, we observed that Ccl5-deficiency had no effect on early lesion formation and CCL5-blockade did not affect monocyte recruitment in Ldlr^-/- mice. Immunostaining of the lesions in Ldlr^-/- mice and reciprocal bone marrow transplantation (BMT) of Ccl5^+/+ and Ccl5^-/- mice revealed that CCL5 is expressed by both myeloid and endothelial cells. BMT experiments were carried out to determine if CCL5 produced by distinct cells has functions that may be concealed in Ccl5^-/-Ldlr^-/- mice. We found that hematopoietic cell-derived CCL5 regulates monocyte recruitment and the abundance of intimal macrophages in 3-week lesions of Ldlr^-/- mice but plays a minor role in 6-week lesions. Our findings suggest that there is a short window in early lesion formation during which myeloid cell-derived CCL5 has a critical role in monocyte recruitment and macrophage abundance.