Enhanced T-helper-1 lymphocyte activation patterns in acute coronary syndromes

Current understanding of cardiovascular autonomic dysfunction in multiple sclerosis

Autoimmune diseases, including multiple sclerosis (MS), are proven to increase the likelihood of developing cardiovascular disease (CVD) due to a robust systemic immune response and inflammation. MS can lead to cardiovascular abnormalities that are related to autonomic nervous system dysfunction by causing inflammatory lesions surrounding tracts of the autonomic nervous system in the brain and spinal cord. CVD in MS patients can affect an already damaged brain, thus worsening the disease course by causing brain atrophy and white matter disease. Currently, the true prevalence of cardiovascular dysfunction and associated death rates in patients with MS are mostly unknown and inconsistent. Treating vascular risk factors is recommended to improve the management of this disease. This review provides an updated summary of CVD prevalence in patients with MS, emphasizing the need for more preclinical studies using animal models to understand the pathogenesis of MS better. However, no distinct studies exist that explore the temporal effects and etiopathogenesis of immune/inflammatory cells on cardiac damage and dysfunction associated with MS, particularly in the cardiac myocardium. To this end, a thorough investigation into the clinical presentation and underlying mechanisms of CVD must be conducted in patients with MS and preclinical animal models. Additionally, clinicians should monitor for cardiovascular complications while prescribing medications to MS patients, as some MS drugs cause severe CVD.

The interplay between T lymphocytes and macrophages in myocardial ischemia/reperfusion injury

Acute myocardial infarction is one of the most important causes of death in the world, causing a huge health and economic burden to the world. It is still a ticklish problem how to effectively prevent reperfusion injury while recovering the blood flow of ischemic myocardium. During the process of myocardial ischemia/reperfusion injury (MI/RI), the modulation of immune cells plays an important role. Monocyte/macrophage, neutrophils and endothelial cells initiate the inflammatory response and induce the release of various inflammatory cytokines, resulting in increased vascular permeability, tissue edema and damage. Meanwhile, T cells were recruited to impaired myocardium and release pro-inflammatory and anti-inflammatory cytokines. T cells and macrophages play important roles in keeping cardiac homeostasis and orchestrate tissue repair. T cells differentiation and macrophages polarization precisely regulates the tissue microenvironment in MI/RI, and shows cross action, but the mechanism is unclear. To identify potential intervention targets and propose ideas for treatment and prevention of MI/RI, this review explores the crosstalk between T lymphocytes and macrophages in MI/RI.

XCR1+ conventional dendritic cell-induced CD4+ T helper 1 cell activation exacerbates cardiac remodeling after ischemic myocardial injury

Cardiac remodeling has no established therapies targeting inflammation. CD4⁺ T-cell subsets have been reported to play significant roles in healing process after ischemic myocardial injury, but their detailed mechanisms of activation remain unknown. To explore immune reactions during cardiac remodeling, we applied a non-surgical model of coronary heart disease (CHD) induced by a high-fat diet (HFD-CHD) in SR-BI^-/-/ApoeR61^h/h mice. Flow cytometry analyses throughout the period of progressive cardiac dysfunction revealed that CD4⁺ T Helper 1 (Th1) cells were predominantly activated in T-cell subsets. Probucol was reported to attenuate cardiac dysfunction after coronary artery ligation model (ligation-MI) in rats. To determine whether probucol suppress cardiac remodeling after HFD-CHD, we treated SR-BI^-/-/ApoeR61^h/h mice with probucol. We found treatment with probucol in HFD-CHD mice reduced cardiac dysfunction, with attenuated activation of Th1 cells. RNA-seq analyses revealed that probucol suppressed the expression of CXCR3, a Th1-related chemokine receptor, in the heart. XCR1⁺ cDC1 cells, which highly expresses the CXCR3 ligands CXCL9 and CXCL10, were predominantly activated after HFD-CHD. XCR1⁺ cDC1 lineage skewing of pre-DC progenitors was observed in bone marrow, with subsequent systemic expansion of XCR1⁺ cDC1 cells after HFD-CHD. Activation of CXCR3⁺ Th1 cell and XCR1⁺ cDC1 cells was also observed in ligation-MI. Notably, post-MI depletion of XCR1⁺ cDC1 cells suppressed CXCR3⁺ Th1 cell activation and prevented cardiac dysfunction. In patient autopsy samples, CXCR3⁺ Th1 and XCR1⁺ cDC1 cells infiltrated the infarcted area. In this study, we identified a critical role of XCR1⁺ cDC1-activated CXCR3⁺ Th1 cells in ischemic cardiac remodeling.

Looking beyond the Skin: Pathophysiology of Cardiovascular Comorbidity in Psoriasis and the Protective Role of Biologics

Psoriasis is a chronic systemic inflammatory disease associated with a higher incidence of cardiovascular disease, especially in patients with moderate to severe psoriasis. It has been estimated that severe psoriasis confers a 25% increase in relative risk of cardiovascular disease, regardless of traditional risk factors. Although the underlying pathogenic mechanisms relating psoriasis to increased cardiovascular risk are not clear, atherosclerosis is emerging as a possible link between skin and vascular affection. The hypothesis that the inflammatory cascade activated in psoriasis contributes to the atherosclerotic process provides the underlying basis to suggest that an anti-inflammatory therapy that improved atherosclerosis would also reduce the risk of MACEs. In this sense, the introduction of biological drugs which specifically target cytokines implicated in the inflammatory cascade have increased the expectations of control over the cardiovascular comorbidity present in psoriasis patients, however, their role in vascular damage processes remains controversial. The aim of this paper is to review the mechanistic link between psoriasis and cardiovascular disease development, as well as analyzing which of the biological treatments could also reduce the cardiovascular risk in these patients, fueling a growing debate on the modification of the general algorithm of treatment.

Understanding Immune Responses to Viruses-Do Underlying Th1/Th2 Cell Biases Predict Outcome?

Emerging and re-emerging viral diseases have increased in number and geographical extent during the last decades. Examples include the current COVID-19 pandemic and the recent epidemics of the Chikungunya, Ebola, and Zika viruses. Immune responses to viruses have been well-characterised within the innate and adaptive immunity pathways with the outcome following viral infection predominantly attributed to properties of the virus and circumstances of the infection. Perhaps the belief that the immune system is often considered as a reactive component of host defence, springing into action when a threat is detected, has contributed to a poorer understanding of the inherent differences in an individual's immune system in the absence of any pathology. In this review, we focus on how these host factors (age, ethnicity, underlying pathologies) may skew the T helper cell response, thereby influencing the outcome following viral infection but also whether we can use these inherent biases to predict patients at risk of a deviant response and apply strategies to avoid or overcome them.

TCF7 is highly expressed in immune cells on the atherosclerotic plaques, and regulating inflammatory signaling via NFκB/AKT/STAT1 signaling

Atherosclerosis, which is the fundamental basis for cardiovascular diseases in the global world, is driven by multiple roles of the immune system in the circulation and vascular plaque. Recent studies demonstrated that T cell infiltrates into aorta plaque and plays an important role in recruiting macrophages to the vascular wall. Here, using single-cell sequencing, we found T cells in patients’ plaques and differentially expressed genes of T cells in atherosclerosis mice. T cells and macrophages were continuously activated in atherosclerotic plaque in patients. Besides, other immune cells also take part in atherogenesis, such as NK cells, granulocytes. IFN/NFκB signaling, the AKT signaling pathway was highly activated in mouse (in vivo) and cell line (in vitro). TCF7, XCL1 were regulated by AKT and NFκB, respectively through Protein-protein Network analysis. Therefore, we attempt to clarify and discover potential genes and new mechanisms associated with atherosclerosis for drug development.

Leukocyte-Mediated Cardiac Repair after Myocardial Infarction in Non-Regenerative vs. Regenerative Systems

Innate and adaptive leukocytes rapidly mobilize to ischemic tissues after myocardial infarction in response to damage signals released from necrotic cells. Leukocytes play important roles in cardiac repair and regeneration such as inflammation initiation and resolution; the removal of dead cells and debris; the deposition of the extracellular matrix and granulation tissue; supporting angiogenesis and cardiomyocyte proliferation; and fibrotic scar generation and resolution. By organizing and comparing the present knowledge of leukocyte recruitment and function after cardiac injury in non-regenerative to regenerative systems, we propose that the leukocyte response to cardiac injury differs in non-regenerative adult mammals such as humans and mice in comparison to cardiac regenerative models such as neonatal mice and adult zebrafish. Specifically, extensive neutrophil, macrophage, and T-cell persistence contributes to a lengthy inflammatory period in non-regenerative systems for adverse cardiac remodeling and heart failure development, whereas their quick removal supports inflammation resolution in regenerative systems for new contractile tissue formation and coronary revascularization. Surprisingly, other leukocytes have not been examined in regenerative model systems. With this review, we aim to encourage the development of improved immune cell markers and tools in cardiac regenerative models for the identification of new immune targets in non-regenerative systems to develop new therapies.

Bima A, Almukadi H, Ibrahim Kutbi H, Jayasheela Shetty P, Ahmad Shaik N, Banaganapalli B. Identifying Significant Genes and Functionally Enriched Pathways in Familial Hypercholesterolemia Using Integrated Gene Co-Expression Network Analysis

Familial hypercholesterolemia (FH) is a monogenic lipid disorder which promotes atherosclerosis and cardiovascular diseases. Owing to the lack of sufficient published information, this study aims to identify the potential genetic biomarkers for FH by studying the global gene expression profile of blood cells. The microarray expression data of FH patients and controls was analyzed by different computational biology methods like differential expression analysis, protein network mapping, hub gene identification, functional enrichment of biological pathways, and immune cell restriction analysis. Our results showed the dysregulated expression of 115 genes connected to lipid homeostasis, immune responses, cell adhesion molecules, canonical Wnt signaling, mucin type O-glycan biosynthesis pathways in FH patients. The findings from expanded protein interaction network construction with known FH genes and subsequent Gene Ontology (GO) annotations have also supported the above findings, in addition to identifying the involvement of dysregulated thyroid hormone and ErbB signaling pathways in FH patients. The genes like CSNK1A1, JAK3, PLCG2, RALA, and ZEB2 were found to be enriched under all GO annotation categories. The subsequent phenotype ontology results have revealed JAK3I, PLCG2, and ZEB2 as key hub genes contributing to the inflammation underlying cardiovascular and immune response related phenotypes. Immune cell restriction findings show that above three genes are highly expressed by T-follicular helper CD4⁺ T cells, naïve B cells, and monocytes, respectively. These findings not only provide a theoretical basis to understand the role of immune dysregulations underlying the atherosclerosis among FH patients but may also pave the way to develop genomic medicine for cardiovascular diseases.

Cerebral derailment after myocardial infarct: mechanisms and effects of the signaling from the ischemic heart to brain

Myocardial infarction (MI) is the leading cause of death among ischemic heart diseases and is associated with several long-term cardiovascular complications, such as angina, re-infarction, arrhythmias, and heart failure. However, MI is frequently accompanied by non-cardiovascular multiple comorbidities, including brain disorders such as stroke, anxiety, depression, and cognitive impairment. Accumulating experimental and clinical evidence suggests a causal relationship between MI and stroke, but the precise underlying mechanisms have not yet been elucidated. Indeed, the risk of stroke remains a current challenge in patients with MI, in spite of the improvement of medical treatment among this patient population has reduced the risk of stroke. In this review, the effects of the signaling from the ischemic heart to the brain, such as neuroinflammation, neuronal apoptosis, and neurogenesis, and the possible actors mediating these effects, such as systemic inflammation, immunoresponse, extracellular vesicles, and microRNAs, are discussed.

An update on the roles of immune system-derived microRNAs in cardiovascular diseases

Cardiovascular diseases (CVD) are a leading cause of human death worldwide. Over the past two decades, the emerging field of cardioimmunology has demonstrated how cells of the immune system play vital roles in the pathogenesis of CVD. MicroRNAs (miRNAs) are critical regulators of cellular identity and function. Cell-intrinsic, as well as cell-extrinsic, roles of immune and inflammatory cell-derived miRNAs have been, and continue to be, extensively studied. Several 'immuno-miRNAs' appear to be specifically expressed or demonstrate greatly enriched expression within leucocytes. Identification of miRNAs as critical regulators of immune system signalling pathways has posed the question of whether and how targeting these molecules therapeutically, may afford opportunities for disease treatment and/or management. As the field of cardioimmunology rapidly continues to advance, this review discusses findings from recent human and murine studies which contribute to our understanding of how leucocytes of innate and adaptive immunity are regulated-and may also regulate other cell types, via the actions of the miRNAs they express, in the context of CVD. Finally, we focus on available information regarding miRNA regulation of regulatory T cells and argue that targeted manipulation of miRNA regulated pathways in these cells may hold therapeutic promise for the treatment of CVD and associated risk factors.

Role of IL-37- and IL-37-Treated Dendritic Cells in Acute Coronary Syndrome

As a chronic inflammatory disease, atherosclerosis is a leading cause of morbidity and mortality in most countries. Inflammation is responsible for plaque instability and the subsequent onset of acute coronary syndrome (ACS), which is one of the leading causes of hospitalization. Therefore, exploring the potential mechanism underlying ACS is of considerable concern, and searching for alternative therapeutic targets is very urgent. Interleukin-37 (IL-37) inhibits the production of proinflammatory chemokines and cytokines and acts as a natural inhibitor of innate and adaptive immunity. Interestingly, our previous study with murine models showed that IL-37 alleviated cardiac remodeling and myocardial ischemia/reperfusion injury. Of note, our clinical study revealed that IL-37 is elevated and plays a beneficial role in patients with ACS. Moreover, dendritic cells (DCs) orchestrate both immunity and tolerance, and tolerogenic DCs (tDCs) are characterized by more secretion of immunosuppressive cytokines. As expected, IL-37-treated DCs are tolerogenic. Hence, we speculate that IL-37- or IL-37-treated DCs is a novel therapeutic possibility for ACS, and the precise mechanism of IL-37 requires further study.

Roles and Mechanisms of TGR5 in the Modulation of CD4+ T Cell Functions in Myocardial Infarction

Bile acid receptor TGR5 has been proved to play protective roles in the process of myocardial infarction (MI). Recently, we found spleen weight of Tgr5^+/+ mice was increased at 7-day post-MI but not in Tgr5^-/- mice. Since the spleen is one of the main resources of immune and inflammatory cells post-MI, we conducted flow cytometry analysis of multiple immune cells in the heart post-MI. It showed the recruitment of CD4⁺ T cells and CD8⁺ T cells was continuously more in the heart of Tgr5^-/- mice post-MI until 7 days after MI. Furthermore, CD4-specific TGR5 depletion mice exhibited aggravated ischemic injury. The mRNA expressions of the markers of Th1 and Treg were upregulated in the heart of Tgr5^-/- mice at 7-day post-MI. These results suggested TGR5 modulates CD4⁺ T cell functions and subsets distribution in the heart, and plays protective roles in myocardial infarction.

T-Cell Molecular Modulation Responses in Atherosclerosis Anergy

Atherosclerosis continues to be a major cause of death in patients with cardiovascular diseases. The cooperative role of immunity has been recently considered in atherosclerotic plaque inflammation, especially adaptive immune response by T cells. In this review, we examine the possible role of T cells in atherosclerosis-mediated inflammation and conceivable therapeutic strategies that can ameliorate complications of atherosclerosis. The cytokines secreted by T-lymphocyte subsets, different pathophysiological profiles of microRNAs (miRs), and the growth factor/receptor axis have diverse effects on the inflammatory cycle of atherosclerosis. Manipulation of miRNA expression and prominent growth factor receptors involved in inflammatory cytokine secretion in atherosclerosis can be considered diagnostic biomarkers in the induction of anergy and blockade of atherosclerotic development. This manuscript reviews immunomodulation of T cells responses in atherosclerosis anergy.

The Relationship Between Type D Personality and the Complexity of Coronary Artery Disease

PURPOSE

The relationship between personality traits and cardiovascular disease has gathered sustained interest over the last years, type -D personality (TDP) being significantly associated with coronary artery disease (CAD). However, data regarding the connection between the TDP and the severity of CAD disease is scarce. The aim of our study was to assess the relationship between TDP and the complexity of CAD, and to compare it with other sociodemographic and clinical features.

PATIENTS AND METHODS

We conducted a cross-sectional case-control clinical-based study on 221 consecutive hospitalized patients with chest pain (60 ± 10.2 years; 131 men), referred for coronary angiography.

RESULTS

TDP was identified in 42 (19%) patients, using the DS 14 scale. Symptomatology profile was evaluated using the SCL-90 scale. Syntax score was greater in the subgroup of patients with TDP in comparison to non-TDP subgroup (26.21±12.03 vs 15.49±8.89, respectively, p<0.001), and most of SCL-90 symptom dimensions have significantly higher levels in the subgroup of TDP with CAD patients (all p < 0.05). Smoking (β=0.132, p=0.037), dyslipidemia (β=0.149, p=0.013), Diabetes Mellitus (β=232, p<0.001), NA dimension of TDP (β=0.255, p<0.001) and SI (β=0.279, p<0.001) dimension of TDP have a significant contribution to the complexity of CAD assessed by Syntax score.

CONCLUSION

TDP was associated with a more complex CAD assessed by Syntax score, and may represent a dynamic interface between the biological and psychological vulnerabilities and the symptoms of CAD.

Very low-calorie ketogenic diet (VLCKD) in patients with psoriasis and obesity: an update for dermatologists and nutritionists

Psoriasis is a chronic skin immune-mediated disease with systemic pro-inflammatory activation; both genetic and lifestyles factors contribute to its pathogenesis and severity. In this context, nutrition plays a significant role, per se, in psoriasis' pathogenesis. Obesity is another important risk factor for psoriasis, and weight reduction may improve psoriasis' clinical severity. The excess body weight, particularly visceral fat mass, can affect both drug's pharmacokinetics and pharmacodynamics. Therefore, psoriasis and obesity share a certain degree of synergy, and the chronic inflammatory state represents the basis of this vicious cycle. Evidence reported that nutrition has different impact on the clinical severity of psoriasis, though some specific diets have been more investigated in clinical studies compared to others. Diets with systemic anti-inflammatory properties seem to have a higher effect on improving the clinical severity of psoriasis. Of interest, very-low-calorie ketogenic diet (VLCKD), through the production of ketone bodies, has been associated with both a significant reduction of body weight and inflammatory state. VLCKD leading to both weight loss and reduction of systemic inflammation may decrease the exacerbation of the clinical manifestations or even it may block the trigger of psoriatic disease. This dietary pattern could represent a potential first-line treatment in psoriatic patients with obesity. The review aims to summarize the current evidence regarding VLCKD and psoriasis with specific reference to antioxidant and anti-inflammatory effects of this dietary pattern.

Down-regulation and Clinical Implication of Galectin-9 Levels in Patients with Acute Coronary Syndrome and Chronic Kidney Disease

In various autoimmune diseases, Galecin-9 (Gal-9) has been shown to regulate the T-cell balance by decreasing Th1 and Th17, while increasing the number of regulatory T cells (Tregs). However, the role of Gal-9 in the patients with acute coronary syndrome (ACS) and chronic kidney disease (CKD) remains unclear. This study aims to measure the Gal-9 levels in serum and peripheral blood mononuclear cells (PBMCs) in patients with ACS plus CKD and examine their clinical implication. The serum levels of Gal-9 were determined by enzyme-linked immunosorbent assay (ELISA), the expression levels of Gal-9, Tim-3, and Foxp3 mRNA in PBMCs were detected by real-time reverse transcription-polymerase chain reaction (RT-PCR), and the expression of Gal-9 on the surface of PBMCs and in PBMCs was analyzed by flow cytometry. Furthermore, the correlation of serum Gal-9 levels with anthropometric and biochemical variables in patients with ACS plus CKD was analyzed. The lowest levels of Gal-9 in serum and PBMCs were found in the only ACS group, followed by the ACS+CKD group, and the normal coronary artery (NCA) group, respectively. Serum Gal-9 levels were increased along with the progression of glomerular filtration rate (GFR) categories of G1 to G4. Additionally, serum Gal-9 levels were negatively correlated with high-sensitivity C-reactive protein (hs-CRP), estimated GFR (eGFR), and lipoprotein(a), but positively with creatinine, age, osmotic pressure, and blood urea nitrogen (BUN). Notably, serum Gal-9 was independently associated with hs-CRP, osmotic pressure, and lipoprotein(a). Furthermore, serum Gal-9 levels were elevated in patients with type 2 diabetes (T2DM) and impaired glucose tolerance (IGT) in ACS group. It was suggested that the levels of Gal-9 in serum and PBMCs were decreased in patients with simple ACS and those with ACS plus CKD, and hs-CRP, eGFR, osmotic pressure and T2DM may have an influence on serum Gal-9 levels.

The Regulatory Role of T Cell Responses in Cardiac Remodeling Following Myocardial Infarction

Ischemic injury to the heart causes cardiomyocyte and supportive tissue death that result in adverse remodeling and formation of scar tissue at the site of injury. The dying cardiac tissue secretes a variety of cytokines and chemokines that trigger an inflammatory response and elicit the recruitment and activation of cardiac immune cells to the injury site. Cell-based therapies for cardiac repair have enhanced cardiac function in the injured myocardium, but the mechanisms remain debatable. In this review, we will focus on the interactions between the adoptively transferred stem cells and the post-ischemic environment, including the active components of the immune/inflammatory response that can mediate cardiac outcome after ischemic injury. In particular, we highlight how the adaptive immune cell response can mediate tissue repair following cardiac injury. Several cell-based studies have reported an increase in pro-reparative T cell subsets after stem cell transplantation. Paracrine factors secreted by stem cells polarize T cell subsets partially by exogenous ubiquitination, which can induce differentiation of T cell subset to promote tissue repair after myocardial infarction (MI). However, the mechanism behind the polarization of different subset after stem cell transplantation remains poorly understood. In this review, we will summarize the current status of immune cells within the heart post-MI with an emphasis on T cell mediated reparative response after ischemic injury.

2019 ATVB Plenary Lecture: Interleukin-2 Therapy in Cardiovascular Disease: The Potential to Regulate Innate and Adaptive Immunity

Regulatory T cells and type-2 innate lymphoid cells represent 2 subsets of immune cells, which have been shown in preclinical models to be important in atherosclerosis and myocardial repair. Regulatory T cells play a crucial role in immune homeostasis and tolerance via their interactions with effector T cells, dendritic cells, and monocytes/macrophages. They also utilize and secrete inhibitory cytokines, including interleukin 10 and transforming growth factor β, to regulate or suppress pathogenic immune responses. Type-2 innate lymphoid cells have an important role in type-2 immune responses and tissue repair through secreting interleukins 5 and 13, as well as a variety of biological mediators and growth factors. Intriguingly, interleukin-2 has emerged as a common cytokine, which can be harnessed to upregulate both cell types, and also has important translational consequences as clinical trials are ongoing for its use in cardiovascular disease. Here, we briefly review the biology of these regulatory immune cell types, discuss the preclinical and clinical evidence for their functions in cardiovascular disease, examine the prospects for clinical translation and current ongoing trials, and finally, postulate how overlap in the mechanisms of upregulation may be leveraged in future treatments for patients.

Innate and adaptive immune cell subsets as risk factors for coronary heart disease in two population-based cohorts

BACKGROUND AND AIMS

Cell-mediated immunity is implicated in atherosclerosis. We evaluated whether innate and adaptive immune cell subsets in peripheral blood are risk factors for coronary heart disease.

METHODS

A nested case-cohort study (n = 2155) was performed within the Multi-Ethnic Study of Atherosclerosis (MESA) and the Cardiovascular Health Study (CHS). Cases of incident myocardial infarction (MI) and incident angina (n = 880 total cases) were compared with a cohort random sample (n = 1275). Immune cell phenotypes (n = 34, including CD14⁺ monocytes, natural killer cells, γδ T cells, CD4⁺, CD8⁺ and CD19⁺ lymphocyte subsets) were measured from cryopreserved cells by flow cytometry. Cox proportional hazards models with adjustment for cardiovascular disease risk factors were used to evaluate associations of cell phenotypes with incident MI and a composite phenotype of incident MI or incident angina (MI-angina) over a median 9.3 years of follow-up. Th1, Th2, Th17, T regulatory (CD4⁺CD25⁺CD127^-), naive (CD4⁺CD45RA⁺), memory (CD4⁺CD45RO⁺), and CD4⁺CD28^- cells were specified as primary hypotheses. In secondary analyses, 27 additional cell phenotypes were investigated.

RESULTS

After correction for multiple testing, there were no statistically significant associations of CD4⁺ naive, memory, CD28^-, or T helper cell subsets with MI or MI-angina in MESA, CHS, or combined-cohort meta analyses. Null associations were also observed for monocyte subsets, natural killer cells, γδ T cells, CD19⁺ B cell and differentiated CD4⁺ and CD8⁺ cell subsets.

CONCLUSIONS

The proportions of peripheral blood monocyte and lymphocyte subsets are not strongly related to the future occurrence of MI or angina in adults free of autoimmune disease.

IL-22 produced by Th22 cells aggravates atherosclerosis development in ApoE-/- mice by enhancing DC-induced Th17 cell proliferation

Th22 cells are a novel subset of CD4+ T cells that primarily mediate biological effects through IL-22, with both Th22 cells and IL-22 being closely associated with multiple autoimmune and chronic inflammatory diseases. In this study, we investigated whether and how Th22 cells affect atherosclerosis. ApoE-/- mice and age-matched C57BL/6J mice were fed a Western diet for 0, 4, 8 or 12 weeks. The results of dynamic analyses showed that Th22 cells, which secrete the majority of IL-22 among the known CD4+ cells, play a major role in atherosclerosis. ApoE-/- mice fed a Western diet for 12 weeks and administered recombinant mouse IL-22 (rIL-22) developed substantially larger plaques in both the aorta and aortic root and higher levels of CD3+ T cells, CD68+ macrophages, collagen, IL-6, Th17 cells, dendritic cells (DCs) and pSTAT3 but lower smooth muscle cell (SMC) α-actin expression than the control mice. Treatment with a neutralizing anti-IL-22 monoclonal antibody (IL-22 mAb) reversed the above effects. Bone marrow-derived DCs exhibited increased differentiation into mature DCs following rIL-22 and ox-LDL stimulation. IL-17 and pSTAT3 were up-regulated after stimulation with IL-22 and ox-LDL in cells cocultured with CD4+ T cells and mature DC supernatant, but this up-regulation was significantly inhibited by IL-6mAb or the cell-permeable STAT3 inhibitor S31-201. Thus, Th22 cell-derived IL-22 aggravates atherosclerosis development through a mechanism that is associated with IL-6/STAT3 activation, DC-induced Th17 cell proliferation and IL-22-stimulated SMC dedifferentiation into a synthetic phenotype.

IL-37 Plays a Beneficial Role in Patients with Acute Coronary Syndrome

Background

Interleukin-37 (IL-37) acts as an inhibitor of innate and adaptive immunity. However, the exact role of IL-37 in the patients with acute coronary syndrome (ACS) remains to be elucidated.

Methods

Patients were classified into 4 groups: normal coronary artery (NCA), stable angina (SA), unstable angina (UA), and acute myocardial infarction (AMI). The circulating Treg, Th1, and Th17 frequencies were measured. The effect of IL-37 on stimulated peripheral blood mononuclear cells (PBMCs) and the influence of IL-37 on DCs were explored. In addition, the role of IL-37-treated tDCs on Treg cell expansion and the stability of these tDCs were also tested.

Results

Our results showed that the circulating Treg frequencies were decreased, while Th1 and Th17 frequencies were increased in ACS patients, and that IL-37 expanded Tregs but suppressed Th1 and Th17 cells in activated PBMCs derived from ACS patients. Of note, IL-37-treated human DCs obtained a tolerogenic phenotype, and such tDCs promoted expansion of Tregs and decreased the Th1 and Th17 populations when cocultured with CD4⁺ T cells. Interestingly, IL-37-treated DCs from patients with ACS are phenotypically and functionally comparable to IL-37-treated DCs from NCA patients, and tolerogenic properties of IL-37-treated DCs were highly stable.

Conclusion

In conclusion, our results reveal a beneficial role of IL-37 in the patients with ACS and suggest that autologous IL-37-treated tDCs may be a novel therapeutic strategy for the patients with ACS.

Single-cell immune landscape of human atherosclerotic plaques

Atherosclerosis is driven by multifaceted contributions of the immune system within the circulation and at vascular focal sites. However, specific characteristics of dysregulated immune cells within atherosclerotic lesions that lead to clinical events such as ischemic stroke or myocardial infarction are poorly understood. Here, using single-cell proteomic and transcriptomic analyses, we uncovered distinct features of both T cells and macrophages in carotid artery plaques of patients with clinically symptomatic disease (recent stroke or transient ischemic attack) compared to asymptomatic disease (no recent stroke). Plaques from symptomatic patients were characterized by a distinct subset of CD4+ T cells and by T cells that were activated and differentiated. Moreover, some T cell subsets in these plaques presented markers of T cell exhaustion. Additionally, macrophages from these plaques contained alternatively activated phenotypes, including subsets associated with plaque vulnerability. In plaques from asymptomatic patients, T cells and macrophages were activated and displayed evidence of interleukin-1β signaling. The identification of specific features of innate and adaptive immune cells in plaques that are associated with cerebrovascular events may enable the design of more precisely tailored cardiovascular immunotherapies.

Increased Ratio of Circulating T-Helper 1 to T-Helper 2 Cells and Severity of Coronary Artery Disease in Patients with Acute Myocardial Infarction: A Prospective Observational Study

Background

This study aimed to determine the association between CD4-positive T-helper (Th) cell subsets, T-helper 1 (Th1) and T-helper 2 (Th2) in patients with acute myocardial infarction (AMI) and the severity of coronary artery disease (CAD) determined by coronary artery angiography.

Material/Methods

Three groups of patients with AMI who underwent coronary angiography and percutaneous coronary intervention (PCI) included patients with stable CAD (n=35), ST-segment elevation myocardial infarction (STEMI) (n=30), and non-STEMI (NSTEMI) (n=35), and controls (n=33). Measurement of high-sensitivity cardiac troponin T (hs-cTnT) was performed. The numbers of circulating CD4-positive Th1 and Th2 cells were measured using flow cytometry. Plasma levels of interferon-γ (IFN-γ) and interleukin-4 (IL-4) were measured using enzyme-linked immunosorbent assay (ELISA).

Results

An increase in the Th1 lymphocyte population was associated with more CAD, and an increased Th1/Th2 ratio was found in patients with NSTEMI and STEMI (controls 7.27±2.98; stable CAD 7.58±2.52; NSTEMI 16.62±2.74; and STEMI 22.32±7.35) (P<0.001). The proportion of Th1 cells and the Th1/Th2 ratio increased as the number of affected arteries, the degree of stenosis, and the lesion length increased. At a median follow-up of 18.2 months, patients with CAD and an increased Th1/Th2 ratio had a significant increase in adverse cardiac events compared with patients with a reduced Th1/Th2 ratio (log-rank, P=0.042).

Conclusions

An increased ratio of circulating Th1 to Th2 cells in patients with AMI was associated with the severity of CAD determined by angiography.

Protective Effects of Angong Niuhuang Pill on Early Atherosclerosis in ApoE-/- Mice by Reducing the Inflammatory Response

Atherosclerosis (AS) is the primary cause of cardiocerebrovascular disease, and inflammation is responsible for the initiation of its pathogenesis. Therefore, targeting inflammatory pathways to prevent AS progression is an ideal strategy. Angong Niuhuang pill (ANP) is a well-known traditional Chinese medicine and has been widely used for thousands of years to treat central nervous system and cardiovascular diseases. In this study, we investigated the role of ANP in reducing inflammation during early AS, using a high-fat diet-induced ApoE-/- mouse model of AS. Compared to those with simvastatin, ANP had no significant effect on serum triglyceride, low-density lipoprotein, and high-density lipoprotein levels. However, it effectively inhibited splenic and vascular inflammation. This agent also reduced the Th17/CD4+T ratio and mRNA expression of IL-6 and increased the Treg/CD4+T ratio and mRNA expression of TGF-β1. Thus, ANP restored Th17/Treg homeostasis in the spleen. It also regulated pro- and anti-inflammatory cytokine expression in the aorta in a similar manner. Further, it downregulated the expression of chemokine receptors (CCR2, CXCR3), their ligands (MCP-1, MCP-2, and MCP-3), and cell adhesion molecules (VCAM-1, ICAM-1) in arterial vessels. These results indicate that ANP can ameliorate the development of early AS, mainly by reducing inflammation instead of acting as an antihyperlipidemic drug.

Interleukin-12p35 Deficiency Reverses the Th1/Th2 Imbalance, Aggravates the Th17/Treg Imbalance, and Ameliorates Atherosclerosis in ApoE-/- Mice

Interleukin- (IL-) 35, a novel functional cytokine of regulatory T cells (Treg) comprised of the IL-12p35 subunit and the other subunit Epstein-Barr virus-induced gene 3 (EBI3), regulates the activity of CD4+ T cells and macrophages, thereby playing a critical role in inflammatory and autoimmune diseases. Previous studies demonstrated that both recombinant mice and human IL-35 attenuated atherosclerosis in ApoE-/- mice. Additionally, EBI3 deficiency enhanced the activation of macrophages and increased atherosclerotic lesions in LDLR-/- mice. This study generated double-deficient mice for ApoE and IL-12p35 (ApoE-/- IL-12p35-/- mice) and investigated the effect of IL-12p35 deficiency on atherosclerosis. IL-12p35 deficiency alleviated Th1/Th2 imbalance, aggravated Th17/Treg imbalance, and attenuated atherosclerotic plaque formation in ApoE-/- mice. Additionally, exogenous rIL-35 treatment reversed the imbalance of Th17/Treg and attenuated atherosclerosis in ApoE-/- mice. These findings suggest that IL-12p35 deficiency ameliorates atherosclerosis in ApoE-/- mice, partially, via attenuating the Th1/Th2 imbalance, although IL-12p35 deficiency aggravates the Th17/Treg imbalance.

Peripheral T cell receptor beta immune repertoire is promptly reconstituted after acute myocardial infarction

BACKGROUND

Acute myocardial infarction (AMI) is characterized by an inflammatory process in which T cell plays a key role. However, the profile of immune microenvironment in AMI is still uncertain. High-throughput sequencing of T cell receptor (TCR) provides deep insight into monitoring the immune microenvironment.

METHODS

30 patients with AMI were enrolled and 30 healthy individuals were recruited as controls. Flow cytometer were used to analyze the distribution of αβ T cells and their CD69 expression from peripheral leukomonocytes. TCRβ repertoire library was amplified by two-round multiplex PCR and detected by next-generation sequencing (NGS).

RESULTS

The percentage of αβ T cells in AMI patients were significantly restricted than those in healthy controls, while the highly activated αβ T cells along with distinguishing usage of variable (V), diversity (D) and joining (J) gene segments were also found in AMI patients. In addition, AMI induced a significantly restricted CDR3 amino acid (AA) diversity and remarkably reconstituted TCR immune repertoires. Finally, we identified several AMI-associated tendency of CDR3 AAs expression after AMI.

CONCLUSIONS

Our work suggests that the aberrant αβ T cells distribution and activation may associated with the pathogenesis of AMI and demonstrates a reconstitution of TCRβ immune repertoire after AMI.

Galectin-1 as an Emerging Mediator of Cardiovascular Inflammation: Mechanisms and Therapeutic Opportunities

Galectin-1 (Gal-1), an evolutionarily conserved β-galactoside-binding lectin, controls immune cell homeostasis and tempers acute and chronic inflammation by blunting proinflammatory cytokine synthesis, engaging T-cell apoptotic programs, promoting expansion of T regulatory (Treg) cells, and deactivating antigen-presenting cells. In addition, this lectin promotes angiogenesis by co-opting the vascular endothelial growth factor receptor (VEGFR) 2 signaling pathway. Since a coordinated network of immunomodulatory and proangiogenic mediators controls cardiac homeostasis, this lectin has been proposed to play a key hierarchical role in cardiac pathophysiology via glycan-dependent regulation of inflammatory responses. Here, we discuss the emerging roles of Gal-1 in cardiovascular diseases including acute myocardial infarction, heart failure, Chagas cardiomyopathy, pulmonary hypertension, and ischemic stroke, highlighting underlying anti-inflammatory mechanisms and therapeutic opportunities. Whereas Gal-1 administration emerges as a potential novel treatment option in acute myocardial infarction and ischemic stroke, Gal-1 blockade may contribute to attenuate pulmonary arterial hypertension.

Interleukin-22, a potent target for treatment of non-autoimmune diseases

Interleukin -22 (IL-22) is a member of interleukin-10 (IL-10) family cytokines that is produced by different types of lymphocytes included in both innate and adaptive immune systems. These lymphocytes include activated T cells, most notably Th17 and Th22 cells, as well as NK cells, γδ T cells, etc. IL-22 mediate its effects via the IL-22-IL-22R complex and subsequent Janus Kinase-signal transduces and activators transcription (JAK-STAT) signaling pathway. According to recent evidence, IL-22 played a critical role in the pathogenesis of many non-autoimmune diseases. In this review, we mainly discussed the recent findings and advancements of the role of IL-22 in several non-autoimmune diseases, such as acute lung injury, atherosclerosis and some bacterial infections, suggesting that IL-22 may have therapeutic potential for treating non-autoimmune diseases.

Systemic Inflammation and Cardiovascular Comorbidity in Psoriasis Patients: Causes and Consequences

Psoriasis is a common inflammatory skin disease characterized by the appearance of red scaly plaques that can affect any part of the body. High prevalence, chronicity, disfiguration, disability, and associated comorbidity make it a challenge for clinicians of multiple specialties. Likewise, its complex pathogenesis, comprising inflammation, hyperproliferation, and angioneogenesis, intrigues numerous scientific disciplines, namely, immunology. From a clinical perspective, the severity of psoriasis is highlighted by its increased mortality, with cardiovascular diseases contributing the highest excess risk. From a scientific point of view, psoriasis has to be considered a systemic inflammatory condition, as blood biomarkers of inflammation are elevated and imaging techniques document sites of inflammation beyond the skin. While the association of psoriasis with cardiovascular diseases is now widely accepted, causes and consequences of this association are controversially discussed. This review comments on epidemiologic, genetic, and mechanistic studies that analyzed the relation between psoriasis and cardiovascular comorbidity. The hypothesis of psoriasis potentially being an independent cardiovascular risk factor, driving atherosclerosis via inflammation-induced endothelial dysfunction, will be discussed. Finally, consequences for the management of psoriasis with the objective to reduce the patients’ excess cardiovascular risk will be pointed out.

The Pivotal Role of Thymus in Atherosclerosis Mediated by Immune and Inflammatory Response

Atherosclerosis is one kind of chronic inflammatory disease, in which multiple types of immune cells or factors are involved. Data from experimental and clinical studies on atherosclerosis have confirmed the key roles of immune cells and inflammation in such process. The thymus as a key organ in T lymphocyte ontogenesis has an important role in optimizing immune system function throughout the life, and dysfunction of thymus has been proved to be associated with severity of atherosclerosis. Based on previous research, we begin with the hypothesis that low density lipoprotein or cholesterol reduces the expression of the thymus transcription factor Foxn1 via low density lipoprotein receptors on the membrane surface and low density lipoprotein receptor related proteins on the cell surface, which cause the thymus function decline or degradation. The imbalance of T cell subgroups and the decrease of naive T cells due to thymus dysfunction cause the increase or decrease in the secretion of various inflammatory factors, which in turn aggravates or inhibits atherosclerosis progression and cardiovascular events. Hence, thymus may be the pivotal role in coronary heart disease mediated by atherosclerosis and cardiovascular events and it can imply a novel treatment strategy for the clinical management of patients with atherosclerosis in addition to different commercial drugs. Modulation of immune system by inducing thymus function may be a therapeutic approach for the prevention of atherosclerosis. Purpose of this review is to summarize and discuss the recent advances about the impact of thymus function on atherosclerosis by the data from animal or human studies and the potential mechanisms.

Effects of Olive Oil Phenolic Compounds on Inflammation in the Prevention and Treatment of Coronary Artery Disease

Coronary artery disease (CAD) is responsible for more than 7 million deaths worldwide. In the early stages of the development of atherosclerotic plaques, cardiovascular risk factors stimulate vascular endothelial cells, initiating an inflammatory process, fundamental in the pathogenesis of CAD. The inclusion of potentially cardioprotective foods, such as olive oil, to the diet, may aid in the control of these risk factors, and in the reduction of cytokines and inflammatory markers. The present review aims to address the interaction between phenolic compounds present in olive oil, and inflammation, in the prevention and treatment of CAD. In vitro and in vivo studies suggest that phenolic compounds, such as hydroxytyrosol, tyrosol, and their secoiridoid derivatives, may reduce the expression of adhesion molecules and consequent migration of immune cells, modify the signaling cascade and the transcription network (blocking the signal and expression of the nuclear factor kappa B), inhibit the action of enzymes responsible for the production of eicosanoids, and consequently, decrease circulating levels of inflammatory markers. Daily consumption of olive oil seems to modulate cytokines and inflammatory markers related to CAD in individuals at risk for cardiovascular diseases. However, clinical studies that have evaluated the effects of olive oil and its phenolic compounds on individuals with CAD are still scarce.

Atorvastatin inhibits the immediate-early response gene EGR1 and improves the functional profile of CD4+T-lymphocytes in acute coronary syndromes

Background- Adaptive immune-response is associated with a worse outcome in acute coronary syndromes. Statins have anti-inflammatory activity beyond lowering lipid levels. We investigated the effects of ex-vivo and in-vivo atorvastatin treatment in acute coronary syndromes on CD4+T-cells, and the underlying molecular mechanisms.Approach and results- Blood samples were collected from 50 statin-naïve acute coronary syndrome patients. We assessed CD4+T-cell activation by flow-cytometry, the expression of 84 T-helper transcription-factors and 84 T-cell related genes by RT-qPCR, and protein expression by Western-blot, before and after 24-hours incubation with increasing doses of atorvastatin: 3-10-26 μg/ml (corresponding to blood levels achieved with doses of 10-40-80 mg, respectively). After incubation, we found a significant decrease in interferon-γ-producing CD4+CD28nullT-cells (P = 0.009) and a significant increase in interleukin-10-producing CD4+CD25highT-cells (P < 0.001). Atorvastatin increased the expression of 2 genes and decreased the expression of 12 genes (in particular, EGR1, FOS,CCR2 and toll like receptor-4; >3-fold changes).The in-vivo effects of atorvastatin were analyzed in 10 statin-free acute coronary syndrome patients at baseline, and after 24h and 48h of atorvastatin therapy (80 mg/daily): EGR1-gene expression decreased at 24h (P = 0.01) and 48h (P = 0.005); EGR1-protein levels decreased at 48h (P = 0.03).Conclusions-In acute coronary syndromes, the effects of atorvastatin on immune system might be partially related to the inhibition of the master regulator gene EGR1. Our finding might offer a causal explanation on why statins improve the early outcome in acute coronary syndromes.

Role of the immune system in cardiac tissue damage and repair following myocardial infarction

INTRODUCTION

The immune system plays a crucial role in the initiation, development, and resolution of inflammation following myocardial infarction (MI). The lack of oxygen and nutrients causes the death of cardiomyocytes and leads to the exposure of danger-associated molecular patterns that are recognized by the immune system to initiate inflammation.

RESULTS

At the initial stage of post-MI inflammation, the immune system further damages cardiac tissue to clear cell debris. The excessive production of reactive oxygen species (ROS) by immune cells and the inability of the anti-oxidant system to neutralize ROS cause oxidative stress that further aggravates inflammation. On the other hand, the cells of both innate and adaptive immune system and their secreted factors are critically instrumental in the very dynamic and complex processes of regulating inflammation and mediating cardiac repair.

CONCLUSIONS

It is important to decipher the balance between detrimental and beneficial effects of the immune system in MI. This enables us to identify better therapeutic targets for reducing the infarct size, sustaining the cardiac function, and minimizing the likelihood of heart failure. This review discusses the role of both innate and adaptive immune systems in cardiac tissue damage and repair in experimental models of MI.

Persistent and selective upregulation of renin-angiotensin system in circulating T lymphocytes in unstable angina

Introduction:

Unstable angina is associated with an acute systemic inflammatory reaction and circulating T lymphocytes are activated. We investigated whether in unstable angina with marked immune system activation a selective upregulation of the circulating T-cell renin–angiotensin system, modulated by angiotensin II, could occur.

Methods:

We studied 13 unstable angina patients, 10 patients with stable angina and 10 healthy subjects. After T-lymphocyte isolation, mRNAs for angiotensin-converting enzyme (ACE) and angiotensin type 1 receptor (AT1-R) were quantified at baseline and after angiotensin II stimulation. ACE activity in cell pellet and supernatant and angiotensin II cell content were measured.

Results:

Plasma renin activity was similar in controls, stable and unstable angina patients. At baseline ACE and AT1-R mRNA levels were higher (P<0.05) in T cells from unstable angina patients than in T cells from stable angina patients and controls, and further increased after angiotensin II addition to cultured T cells. ACE activity of unstable angina T cells was significantly higher than that of T cells from controls and stable angina patients. Only in T cells from unstable angina patients did angiotensin II stimulation cause the almost complete release of ACE activity in the supernatant.

Conclusions:

The circulating T-cell-based renin–angiotensin system from unstable angina patients was selectively upregulated. In vivo unstable angina T cells could locally increase angiotensin II concentration in tissues where they migrate independently of the circulating renin–angiotensin system.

Cortistatin reduces atherosclerosis in hyperlipidemic ApoE-deficient mice and the formation of foam cells

Atherosclerosis is a chronic inflammatory cardiovascular disease that is responsible of high mortality worldwide. Evidence indicates that maladaptive autoimmune responses in the arterial wall play critical roles in the process of atherosclerosis. Cortistatin is a neuropeptide expressed in the vascular system and atherosclerotic plaques that regulates vascular calcification and neointimal formation, and inhibits inflammation in different experimental models of autoimmune diseases. Its role in inflammatory cardiovascular disorders is largely unexplored. The aim of this study is to investigate the potential therapeutic effects of cortistatin in two well-established preclinical models of atherosclerosis, and the molecular and cellular mechanisms involved. Systemic treatment with cortistatin reduced the number and size of atherosclerotic plaques in carotid artery, heart, aortic arch and aorta in acute and chronic atherosclerosis induced in apolipoprotein E-deficient mice fed a high-lipid diet. This effect was exerted at multiple levels. Cortistatin reduced Th1/Th17-driven inflammatory responses and increased regulatory T cells in atherosclerotic arteries and lymphoid organs. Moreover, cortistatin reduced the capacity of endothelial cells to bind and recruit immune cells to the plaque and impaired the formation of foam cells by enhancing cholesterol efflux from macrophages. Cortistatin emerges as a new candidate for the treatment of the clinical manifestations of atherosclerosis.

Changes in CD4+CD25+ Tregs in the pathogenesis of atherosclerosis in ApoE-/- mice

The goal of this study was to observe the pathological characteristics of atherosclerotic plaques in the aortic walls of ApoE^-/- and C57BL/6J mice and the changes of CD4⁺CD25⁺ regulatory T cells (Tregs) in atherosclerotic mice. Twenty ApoE^-/- mice were split into high-fat diet (AH) and normal diet (AN) groups and 10 C57BL/6J male mice were designated as the control group (BN). The serum concentrations of IL-10 and TGF-β1 were detected by enzyme-linked immunosorbent assay; paraffin sections of the aorta were stained with hematoxylin & eosin, and morphometric parameters were measured using the Image Pro Plus 6.0 system. Verhoeff stain was used to observe the distribution of elastic fibers, and immunohistochemical staining was performed to verify the phenotype of the forkhead box protein 3 (Foxp3⁺) CD25⁺ cells in the atherosclerotic tissue. The proportion of CD4⁺CD25⁺ Tregs in the spleen was calculated by flow cytometry. The thickness of the intima, the intima/media ratio, the plaque area, and the plaque/lumen ratio of mice in AN group were significantly larger than those of mice in BN group. The thickness of the intima, the plaque area, and the plaque/lumen ratio of the mice in AH group were significantly increased compared with those of the AN group mice. The serum concentrations of IL-10 and TGF-β1 and the percentage of splenic CD4⁺CD25⁺ Tregs in AN group mice were significantly decreased compared with the control group. The serum concentrations of IL-10 and TGF-β1 and the percentage of splenic CD4⁺CD25⁺ Tregs in the mice in AH group were significantly decreased compared with those in AN group. The proportions of Foxp3⁺ and CD25⁺ cells within the total lymphocyte population were significantly decreased in AH group mice compared with those in AN group mice. Atherosclerosis in an experimental mouse model was correlated with Treg depletion in the lymphoid tissues and plaques, indicating the important antiatherosclerotic role of CD4⁺CD25⁺ Tregs. Impact statement In this article, we conclude that Tregs decreased with atherosclerosis (AS) as determined in ApoE knockout mice fed a high fat diet. It is an important matter for understanding the AS pathology.

Adaptive Immunity Dysregulation in Acute Coronary Syndromes: From Cellular and Molecular Basis to Clinical Implications

Although the early outcome of acute coronary syndrome (ACS) has considerably improved in the last decade, cardiovascular diseases still represent the main cause of morbidity and mortality worldwide. This is mainly because recurrence of ACS eventually leads to the pandemics of heart failure and sudden cardiac death, thus calling for a reappraisal of the mechanisms responsible for coronary instability. This review discusses recent advances in our understanding of how adaptive immunity contributes to the pathogenesis of ACS and the clinical implications that arise from these new pathogenic concepts.

Stabilization of high-risk plaques

The prevalence of atherosclerotic cardiovascular diseases (ASCVDs) is increasing globally and they have become the leading cause of death in most countries. Numerous experimental and clinical studies have been conducted to identify major risk factors and effective control strategies for ASCVDs. The development of imaging modalities with the ability to determine the plaque composition enables us to further identify high-risk plaque and evaluate the effectiveness of different treatment strategies. While intensive lipid-lowering by statins can stabilize or even regress plaque by various mechanisms, such as the reduction of lipid accumulation in a necrotic lipid core, the reduction of inflammation, and improvement of endothelial function, there are still considerable residual risks that need to be understood. We reviewed important findings regarding plaque vulnerability and some encouraging emerging approaches for plaque stabilization.

Effect of Coronary Percutaneous Revascularization on Interferon-γ and Interleukin-10 Producing CD4+ T Cells during Acute Myocardial Infarction

T lymphocytes play an important role in the induction and progression of acute coronary syndromes (ACS). To gain insight into how different T cell subsets can influence ACS, we analyzed the frequencies of circulating CD4+T cells producing either pro-inflammatory interferon(IFN)-γ or anti-inflammatory interleukin (IL)-10 in subjects presenting with ST-elevation myocardial infarction (STEMI). The effect of coronary bare metal (BS) and paclitaxel-eluting stent (PES) on the balance between CD4+IFN-γ+ and CD4+IL-10+ lymphocytes was also investigated. Peripheral blood mononuclear cells (PBMC) were isolated from 38 consecutive patients with STEMI before and 48 hrs or 6 days after implantation of either BS or PES. Twenty patients with no history of coronary artery disease were included as basal controls. PBMC were stimulated in vitro with anti-CD3/anti-CD28 monoclonal antibodies, and CD4+IFN-γ+ or CD4+IL-10+ T cells were detected by flow cytometry intracellular staining. The frequency of peripheral CD4+IL-10+ T cells was significantly higher in STEMI patients as compared with controls. Conversely, the frequency of CD4+IFN-γ+ T lymphocytes did not differ between STEMI and subjects without history of coronary artery disease. Six days after the revascularization procedure, the percentage of CD4+IL-10+ T cells was significantly decreased in BS but not in the PES group, whereas the relative percentage of CD4+IFN-γ+ T lymphocytes were diminished in both groups as compared with baseline levels. Our data indicate that STEMI is associated with a peripheral expansion of CD4+IL-10+T lymphocytes, and that primary coronary revascularization with implantation of either BS or PES is followed by a reduction in circulating CD4+IFN-γ+ T lymphocytes. PES implantation, however, appears to inhibit the relative decrease of the IL-10 producing lymphocyte as observed in BS implanted patients, shifting the balance between pro-inflammatory and anti-inflammatory T cell populations in favor of the latter.

Interleukin-2/Anti-Interleukin-2 Immune Complex Attenuates Cardiac Remodeling after Myocardial Infarction through Expansion of Regulatory T Cells

CD4+CD25+Foxp3+ regulatory T cells (Treg cells) have protective effects in wound healing and adverse ventricular remodeling after myocardial infarction (MI). We hypothesize that the interleukin- (IL-) 2 complex comprising the recombinant mouse IL-2/anti-IL-2 mAb (JES6-1) attenuates cardiac remodeling after MI through the expansion of Treg. Mice were subjected to surgical left anterior descending coronary artery ligation and treated with either PBS or IL-2 complex. The IL-2 complex significantly attenuates ventricular remodeling, as demonstrated by reduced infarct size, improved left ventricular (LV) function, and attenuated cardiomyocyte apoptosis. The IL-2 complex increased the percentage of CD4+CD25+Foxp3+ Treg cells, which may be recruited to the infarcted heart, and decreased the frequencies of IFN-γ- and IL-17-producing CD4+ T helper (Th) cells among the CD4+Foxp3− T cells in the spleen. Furthermore, the IL-2 complex inhibited the gene expression of proinflammatory cytokines as well as macrophage infiltrates in the infarcted myocardium and induced the differentiation of macrophages from M1 to M2 phenotype in border zone of infarcted myocardium. Our studies indicate that the IL-2 complex may serve as a promising therapeutic approach to attenuate adverse remodeling after MI through expanding Treg cells specifically.

Functional and homeostatic defects of regulatory T cells in patients with coronary artery disease

OBJECTIVE

Regulatory T cells (Tregs) are considered atheroprotective, and low levels have been associated with the acute coronary syndrome (ACS), particularly non-ST elevation (NSTE)-ACS. However, the functional properties as well as homeostasis of Tregs are mainly unknown in coronary artery disease (CAD). Here, we investigated the composition and functional properties of naïve (n) and memory (m)Tregs in patients with NSTE-ACS and in patients 6-12 months post-ACS.

METHODS

Based on the expression of CD25, FOXP3, CD127, CD45RA, CD39 and CTLA-4, Treg subsets were defined by flow cytometry in whole blood or isolated CD4(+) T cells. The functional properties of nTregs and mTregs were examined in terms of proliferative capacity and modulation of cytokine secretion. To understand the potential consequences of Treg defects, we also investigated correlations with lipopolysaccharide (LPS)-induced cytokine secretion and ultrasound-defined carotid atherosclerosis.

RESULTS

Both NSTE-ACS and post-ACS patients exhibited reduced levels of nTregs (P < 0.001) compared with healthy control subjects, but without compensatory increases in mTregs. Both nTregs and mTregs from patients showed significantly lower replicative rates and impaired capacity to modulate T-cell proliferation and secretion of interferon-gamma and IL-10. The Treg defect was also associated with LPS-induced cytokine secretion and increased burden of carotid atherosclerosis.

CONCLUSION

Our results demonstrate a functional and homeostatic Treg defect in patients with NSTE-ACS and also in stabilized patients 6-12 months after ACS. Moreover, this defect was associated with a subclinical proinflammatory and atherogenic state. We believe that the failure to preserve Treg function and homeostasis reflects a need for immune-restoring strategies in CAD.

Effects of the Sympathetic Nervous System on Regulatory T Cell and T Helper 1 Chemokine Expression in Patients with Acute Coronary Syndrome

OBJECTIVE

To observe the effects of sympathetic overactivity on the immune system involved in the imbalance of T helper (Th) lymphocytes, we investigated the correlation between autonomic dysregulation and the generation of regulatory T (Treg) and Th1 chemokines in patients with acute coronary syndrome (ACS).

METHODS

Blood samples obtained from patients with coronary artery disease and controls were analyzed for levels of Th1 and Treg cells and their associated cytokines by flow cytometry. In addition, the activity of the cyclic adenosine monophosphate (cAMP), the levels of norepinephrine (NE), epinephrine (EPI) and serum cytokines, and the activity of protein kinase A (PKA) were analyzed by Western blot, radioimmunoassay, high-performance liquid chromatography and enzyme-linked immunoassay, respectively. All subjects were evaluated for heart rate variability (HRV).

RESULTS

Levels of Th1 cells and T-bet (a T-box transcription factor), NE, EPI, cAMP and PKA significantly increased (all p < 0.01) whereas HRV and levels of Treg cells and STAT5 decreased (all p < 0.01) in ACS patients compared to patients with stable angina and controls. The disorder of Th1 and Treg cells is closely related to the activation of cAMP-PKA induced by hyperactivity of the sympathetic system.

CONCLUSIONS

This study showed that the abnormalities in specific subsets of CD4+ T cells are associated with sympathetic hyperactivity in ACS patients. It may provide surprising insights into the pathogenesis of arteriosclerosis, involving the regulation of the sympathetic nervous system on immune inflammation.

Altered Maturation Status and Possible Immune Exhaustion of CD8 T Lymphocytes in the Peripheral Blood of Patients Presenting With Acute Coronary Syndromes

OBJECTIVE

Inflammation in response to oxidized lipoproteins is thought to play a key role in acute coronary syndromes (ACS), but the pattern of immune activation has not been fully characterized. We sought to perform detailed phenotypic and functional analysis of CD8 T lymphocytes from patients presenting with ACS to determine activation patterns and potential immunologic correlates of ACS.

APPROACH AND RESULTS

We used polychromatic flow cytometry to analyze the cytokine production profiles of naïve, effector, and memory CD8 T cells in patients with ACS compared with control subjects with stable coronary artery disease. ACS was associated with an altered distribution of circulating CD8(+) T-cell maturation subsets with reduced proportions of naïve cells and expansion of effector memory cells. ACS was also accompanied by impaired interleukin-2 production by phenotypically naïve CD8 T cells. These results were validated in a second replication cohort. Naïve CD8 cells from patients with ACS also had increased expression of programmed cell death-1, which correlated with interleukin-2 hypoproduction. In vitro, stimulation of CD8 T cells with oxidized low-density lipoprotein was sufficient to cause programmed cell death-1 upregulation and diminished interleukin-2 production by naïve CD8 T cells.

CONCLUSIONS

In this exploratory analysis, naïve CD8(+) T cells from patients with ACS show phenotypic and functional characteristics of immune exhaustion: impaired interleukin-2 production and programmed cell death-1 upregulation. Exposure to oxidized low-density lipoprotein recapitulates these features in vitro. These data provide evidence that oxidized low-density lipoprotein could play a role in immune exhaustion, and this immunophenotype may be a biomarker for ACS.

Lymphocyte subpopulations in myocardial infarction: a comparison between peripheral and intracoronary blood

The frequency and profile of lymphocyte subsets within the culprit coronary artery were investigated in 33 patients with myocardial infarction and compared to their systemic circulating counterparts. T cell subsets including CD4⁺CD28null, activated and regulatory T-cells, TH1/TH2/TH17 phenotypes, NK and B-cells were studied in intracoronary (IC) and arterial peripheral blood (PB) samples. CD4⁺CD28null T-lymphocytes were significantly increased in IC compared to PB (3.7 vs. 2.9 %, p < 0.0001). Moreover, patients with more than 6 h of evolution of STEMI exhibited higher levels of CD4⁺CD28null T-cells suggesting that this subset may be associated with more intense myocardial damage. The rare NK subpopulation CD3⁻CD16⁺CD56⁻ was also increased in IC samples (5.6 vs. 3.9 %, p = 0.006). CD4⁺CD28null T-cells and CD3⁻CD16⁺CD56⁻ NK subpopulations were also associated with higher CK levels. Additionally, IFN-γ and IL10 were significantly higher in IC CD4⁺ lymphocytes. Particular immune cell populations with a pro-inflammatory profile at the site of onset were increased relative to their circulating counterparts suggesting a pathophysiological role of these cells in plaque instability, thrombi and myocardial damage.