Indoleamine 2,3-Dioxygenase (IDO) Enzyme Links Innate Immunity and Altered T-Cell Differentiation in Non-ST Segment Elevation Acute Coronary Syndrome.

Atherosclerosis is a chronic inflammatory disease characterized by a complex interplay between innate and adaptive immunity. Dendritic cells (DCs) play a key role in T-cell activation and regulation by promoting a tolerogenic environment through the expression of the immunosuppressive enzyme indoleamine 2,3-dioxygenase (IDO), an intracellular enzyme involved in tryptophan catabolism. IDO expression and activity was analyzed in monocytes derived DCs (MDDCs) from non-ST segment elevation myocardial infarction (NSTEMI) patients, stable angina (SA) patients and healthy controls (HC) by real-time quantitative polymerase chain reaction (RT-qPCR) before and after in vitro maturation with lipopolysaccharide (LPS). The amount of tryptophan catabolite; kynurenine; was evaluated in the culture supernatants of mature-MDDCs by ELISA assay. Autologous mixed lymphocyte reaction (MLR) between mature-MDDCs and naïve T-cells was carried out to study the differentiation towards T-helper 1 (Th1) and induced regulatory T-cells (iTreg). Analysis of IDO mRNA transcripts in mature-MDDCs revealed a significant reduction in cells isolated from NSTEMI (625.0 ± 128.2; mean ± SEM) as compared with those from SA (958.5 ± 218.3; p = 0.041) and from HC (1183.6 ± 231.6; p = 0.034). Furthermore; the concentration of kynurenine was lower in NSTEMI patients (2.78 ± 0.2) and SA (2.98 ± 0.25) as compared with HC (5.1 ± 0.69 ng/mL; p = 0.002 and p = 0.016; respectively). When IDO-competent mature-MDDCs were co-cultured with allogeneic naïve T-cells, the ratio between the percentage of generated Th1 and iTreg was higher in NSTEMI (4.4 ± 2.9) than in SA (1.8 ± 0.6; p = 0.056) and HC (0.9 ± 0.3; p = 0.008). In NSTEMI, the tolerogenic mechanism of the immune response related to IDO production by activated MDDCs is altered, supporting their role in T-cell dysregulation.

The VENERE Study: EffectiVenEss of a Rehabilitation Treatment With Nordic Walking in ObEse or OveRweight Diabetic PatiEnts With Cardiovascular Disease.

Background: Nordic walking (NW) has several potential benefits for individuals with cardiovascular (CV) disease, type 2 diabetes, and obesity and/or overweight. NW improves cardiovascular health, including exercise capacity and blood pressure control. NW enhances glycemic control and insulin sensitivity in diabetes, and aids in weight management and body composition improvement. NW offers additional advantages, such as improvement in muscular strength, joint mobility, physical activity levels, and psychological well-being. Methods: This open-label study with 3 arms will aim to evaluate the efficacy, safety, and adherence to exercise prescription in obese and/or overweight diabetic patients with CV complications. The primary objective will be to assess the CV performance of participants after a 6-month and a 12-month follow-up period, following a 3-month NW intervention, compared with standard rehabilitation, and with cardiological counseling (control group) training lasting 3 months. Results: The results of the study will provide valuable insights into the comparative effectiveness of a NW intervention vs standard rehabilitation and control group training in improving CV performance in obese and/or overweight diabetic patients with CV complications. Additionally, safety and adherence data will help inform the feasibility and sustainability of the exercise prescription over an extended period. Conclusions: These findings may have implications for the development of tailored exercise programs for this specific patient population, with the aim of optimizing CV health outcomes. Clinical Trials Registration: NCT05987410.

Contexte: La marche nordique offre plusieurs bienfaits potentiels aux personnes atteintes d'une maladie cardiovasculaire (CV), de diabète de type 2, de surpoids ou d'obésité. Elle améliore la santé cardiovasculaire, notamment l'endurance à l'effort et la régulation de la pression artérielle, en plus de favoriser l'équilibre glycémique et d'accroître la sensibilité à l'insuline chez les personnes diabétiques. Elle facilite également la gestion du poids et l'amélioration de la composition corporelle. Par ailleurs, la marche nordique présente d'autres avantages, comme l'augmentation de la force musculaire, de la mobilité articulaire, du niveau d'activité physique et du bien-être psychologique. Méthodologie: Cette étude ouverte à 3 groupes vise à évaluer l'efficacité, la sécurité et l'observance des exercices prescrits chez des sujets diabétiques obèses ou en surpoids présentant des complications CV. Le principal objectif consistera à évaluer la performance CV des participants au cours d'une période de suivi de 6 et 12 mois après un programme de marche nordique de 3 mois, comparativement à un programme de réadaptation standard et à un programme d'encadrement en soins CV (groupe témoin) de 3 mois. Résultats: Les résultats de l'étude fourniront de précieux renseignements sur l'efficacité d'un programme de marche rapide comparativement à un programme de réadaptation standard et à un programme d'encadrement (groupe témoin) pour améliorer la performance CV chez des sujets diabétiques obèses ou en surpoids présentant des complications CV. Les données relatives à la sécurité et à l'observance permettront également d'évaluer la faisabilité et la viabilité de la prescription d'exercices sur une longue période. Conclusions: Ces résultats pourraient s'avérer utiles dans l'élaboration de programmes d'exercices spécifiquement conçus pour cette population de patients, afin d'optimiser les résultats en santé CV. Numéro d'inscription de l'essai clinique: NCT05987410.

Reversible atrial gap junction remodeling during hypoxia/reoxygenation and ischemia: a possible arrhythmogenic substrate for atrial fibrillation.

Alteration of cardiomyocyte gap-junctions and component connexins (Cx) has been suggested to contribute to the development of atrial fibrillation (AF), including postoperative AF. We tested different possible stimuli, such as hypoxia and ischemia, influencing Cx43 and Cx40 expression and distribution in cultured atrial cells (HL-1) and reversibility of these processes after reoxygenation. Western-blot analysis and immunostaining using anti-Cx43, anti-Cx40 and anti-zonula occludens polyclonal antibodies were performed. HL-1 cells exposed to hypoxia for 24 and 48 h showed a reduction of Cx43 protein levels by 75% and 90% respectively (p < 0.001). During reoxygenation following 24 h of hypoxia, Cx43 levels increased to reach the basal level within 48 h, while they remained at low level during reoxygenation following 48 h of hypoxia. Furthermore, atrial cardiomyocytes subjected to simulated ischemia (SI) were incubated in normoxic and hypoxic conditions for 3, 6, 9, 12 h. Atrial cardiomyocytes subjected to SI in addition to normoxia showed a progressive reduction of Cx43 levels beginning from 3 h. During SI and hypoxia, atrial Cx43 levels showed an initial decrease after 3 h with a subsequent rescue beginning from 6 h of exposure (p = 0.001). Hypoxia and ischemia per se downregulate Cx43 protein expression in atrial cardiomyocytes, but protein downregulation is reversible, depending on hypoxia duration and the association of the two triggers. These alterations characterize several conditions and might contribute to the generation of an arrhythmogenic substrate leading to AF onset and/or maintenance.

Restricted T-Cell Repertoire in the Epicardial Adipose Tissue of Non-ST Segment Elevation Myocardial Infarction Patients.

Aims: Human epicardial adipose tissue, a dynamic source of multiple bioactive factors, holds a close functional and anatomic relationship with the epicardial coronary arteries and communicates with the coronary artery wall through paracrine and vasocrine secretions. We explored the hypothesis that T-cell recruitment into epicardial adipose tissue (EAT) in patients with non-ST segment elevation myocardial infarction (NSTEMI) could be part of a specific antigen-driven response implicated in acute coronary syndrome onset and progression. Methods and Results: We enrolled 32 NSTEMI patients and 34 chronic coronary syndrome (CCS) patients undergoing coronary artery bypass grafting (CABG) and 12 mitral valve disease (MVD) patients undergoing surgery. We performed EAT proteome profiling on pooled specimens from three NSTEMI and three CCS patients. We performed T-cell receptor (TCR) spectratyping and CDR3 sequencing in EAT and peripheral blood mononuclear cells of 29 NSTEMI, 31 CCS, and 12 MVD patients. We then used computational modeling studies to predict interactions of the TCR beta chain variable region (TRBV) and explore sequence alignments. The EAT proteome profiling displayed a higher content of pro-inflammatory molecules (CD31, CHI3L1, CRP, EMPRINN, ENG, IL-17, IL-33, MMP-9, MPO, NGAL, RBP-4, RETN, VDB) in NSTEMI as compared to CCS (P < 0.0001). CDR3-beta spectratyping showed a TRBV21 enrichment in EAT of NSTEMI (12/29 patients; 41%) as compared with CCS (1/31 patients; 3%) and MVD (none) (ANOVA for trend P < 0.001). Of note, 11/12 (92%) NSTEMI patients with TRBV21 perturbation were at their first manifestation of ACS. Four patients with the first event shared a distinctive TRBV21-CDR3 sequence of 178 bp length and 2/4 were carriers of the human leukocyte antigen (HLA)-A*03:01 allele. A 3D analysis predicted the most likely epitope able to bind HLA-A3*01 and interact with the TRBV21-CDR3 sequence of 178 bp length, while the alignment results were consistent with microbial DNA sequences. Conclusions: Our study revealed a unique immune signature of the epicardial adipose tissue, which led to a 3D modeling of the TCRBV/peptide/HLA-A3 complex, in acute coronary syndrome patients at their first event, paving the way for epitope-driven therapeutic strategies.

Inflammasome, T Lymphocytes and Innate-Adaptive Immunity Crosstalk: Role in Cardiovascular Disease and Therapeutic Perspectives.

Over the past few decades, lot of evidences have shown atherosclerosis as a chronic progressive disease with an exquisite inflammatory feature. More recently, the role of innate immune response in the onset and progression of coronary artery disease (CAD) and an adaptive immunity imbalance, mostly involving T cell sub-sets, have been documented. Therefore, like in many other inflammatory and autoimmune disorders, an altered innate-adaptive immunity crosstalk could represent the key of the inflammatory burden leading to atherosclerotic plaque formation and progression and to the breakdown of plaque stability. In this review, we will address the role of inflammasome in innate immunity and in the imbalance of adaptive immunity. We will discuss how this altered immune crosstalk is related to CAD onset and progression. We will also discuss how unravelling the key molecular mechanisms is of paramount importance in the development of therapeutic tools to delay the chronic progression and prevent the acute destabilization of atherosclerotic plaque.

Alterations of Hyaluronan Metabolism in Acute Coronary Syndrome: Implications for Plaque Erosion.

BACKGROUND: Superficial erosion currently causes at least one-third of acute coronary syndromes (ACS), and its incidence is increasing. Yet, the underlying mechanisms in humans are still largely unknown. OBJECTIVES: The authors sought to assess the role of hyaluronan (HA) metabolism in ACS. METHODS: Peripheral blood mononuclear cells were collected from ACS (n = 66), stable angina (SA) (n = 55), and control (CTRL) patients (n = 45). The authors evaluated: 1) gene expression of hyaluronidase 2 (HYAL2) (enzyme degrading high-molecular-weight HA to its proinflammatory 20-kDa isoform) and of CD44v1, CD44v4, and CD44v6 splicing variants of HA receptor; and 2) HYAL2 and CD44 protein expression. Moreover, they compared HYAL2 and CD44 gene expression in ACS patients with plaque erosion (intact fibrous cap and thrombus) and in ACS patients with plaque rupture, identified by optical coherence tomography analysis. RESULTS: Gene expression of HYAL2, CD44v1, and CD44v6 were significantly higher in ACS as compared with SA (p = 0.003, p < 0.001, and p = 0.033, respectively) and CTRL subjects (p < 0.001, p < 0.001, and p = 0.009, respectively). HYAL2 protein expression was significantly higher in ACS than in SA (p = 0.017) and CTRL (p = 0.032), whereas no differences were found in CD44 protein expression. HYAL2 and CD44v6 gene expression was significantly higher in patients with plaque erosion than in those with plaque rupture (p = 0.015 and p = 0.029, respectively). CONCLUSIONS: HYAL2 and CD44v6 splicing variants seem to play an important role in ACS, in particular when associated with plaque erosion. After further validation, HYAL2 might represent a potentially useful biomarker for the noninvasive identification of this mechanism of coronary instability.

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.

Epicardial adipose tissue microbial colonization and inflammasome activation in acute coronary syndrome.

BACKGROUND: Epicardial adipose tissue (EAT) has a close functional and anatomic relationship with epicardial coronary arteries. Accumulating evidence suggests that host microbiome alterations may play a role in several inflammatory/immune disorders, triggering a robust proinflammatory response also involving interleukin-1ß (IL-1ß) and the NALP3 inflammasome. In the current study, we explore the hypothesis that in patients with non-ST elevation acute coronary syndrome (ACS), EAT contains potentially pro-atherosclerotic bacteria that might elicit inflammasome activation. METHODS: EAT samples were obtained during coronary artery bypass grafting from ACS (n=18) and effort stable angina (SA; n=16) patients, and as controls, from patients with angiographically normal coronary arteries undergoing surgery for mitral insufficiency (MVD; n=13). In all patients, NALP3 and proIL-1ß mRNA expressions were evaluated with qRT-PCR. In 3 patients from each group, EAT microbiota composition was determined using next-generation sequencing technologies. RESULTS: In EAT, mRNA expression of both NALP3 and pro-IL1ß was significantly higher in ACS than in SA and MVD (P=0.028 and P=0.005, respectively). A broad range of bacterial species (n=76) was identified in both ACS and SA, with different predominant species. In contrast, microbial DNA was barely observed in MVD. CONCLUSIONS: Our study demonstrated the presence of bacterial DNA directly into EAT, surrounding diseased coronary arteries, of patients with ACS. Furthermore, ACS is associated with NALP3/inflammasome pathway activation in EAT. Our data suggest that the EAT environment is susceptible to microbial colonization that might stimulate a proinflammatory response. These findings add new elements to the pathogenesis of ACS and suggest novel therapeutic targets.

Increased risk of myocardial infarction with dabigatran: fact or fiction?

Dabigatran is a direct, competitive inhibitor of thrombin recently approved for the prophylaxis of stroke and systemic embolism in patients with nonvalvular atrial fibrillation. In some of the clinical trials evaluating the efficacy and safety of dabigatran in different clinical settings [i.e., prevention of venous thromboembolism (VTE) after orthopedic surgery, secondary prevention of VTE, and acute coronary syndromes (ACS)], a trend toward an increase in acute coronary events among patients receiving dabigatran has been reported, thus raising concerns of a possible relationship between dabigatran and myocardial infarction, especially in high-risk patients. However, as shown in our article, current evidence is inconclusive on this topic; more data are needed to detail this hypothetical association, and other considerations, such as the well-known protective effect of warfarin against ACS, should be taken into account as a possible explanation.

[Catheter ablation as first-line therapy for atrial fibrillation: an analysis of available evidence]. / L'ablazione transcatetere come terapia di prima linea della fibrillazione atriale: analisi delle attuali evidenze.

In patients with symptomatic atrial fibrillation refractory to antiarrhythmic therapy, catheter ablation is effective in restoring and maintaining sinus rhythm, in reducing hospitalization and improving quality of life. On the other hand, the role of catheter ablation as first-line therapy for atrial fibrillation is still controversial and has been recently evaluated by two randomized controlled trials and two consecutive case series. These studies showed the superiority of catheter ablation over antiarrhythmic therapy for the rhythm control of atrial fibrillation, with similar rates of complications between the two groups. According to these results, catheter ablation could be considered as first-line therapy for patients with symptomatic paroxysmal atrial fibrillation without significant heart disease.

Infections, immunity and atherosclerosis: pathogenic mechanisms and unsolved questions.

The role of inflammation and immunity in the pathogenesis and clinical manifestations of atherosclerotic disease has been widely studied. Common infectious diseases can be associated with a chronic inflammatory state which is the hallmark of atherosclerosis, thus suggesting a possible link between the two pathological conditions. Therefore, a great number of studies have tested the "infection hypothesis", but their results are conflicting. Nevertheless, several molecular and biological mechanisms possibly involved in the complex relationship between infections, immune response, vascular wall damage and atherosclerosis onset and progression have been described. The purpose of this article is to offer an overview of the principal mechanisms and molecular pathways that probably constitute the most relevant biological substrate on which the infection hypothesis is founded; some of these mechanisms are not fully understood yet. Nevertheless, their comprehension could be essential for the development of new preventive and therapeutic strategies.

Inflammatory markers in heart failure: hype or hope?

Heart failure is a growing global epidemic that involves in its pathophysiology a proinflammatory state. Since the first description of elevated cytokine levels in this setting, there has been increasing interest in understanding the role of these molecules in left-ventricular remodeling and function. Over the years, intense research on the 'cytokine theory' of heart failure has allowed evaluation of the role of inflammatory biomarkers not only as pathogenetic mediators, but also as potential tools in the diagnosis and risk stratification of heart failure patients. Whereas current evidence does not support the use of inflammatory biomarkers for the diagnosis of heart failure, the assessment of their levels and the connection between their changes and changes in clinical status and prognosis has been well validated. At present, the utility of anti-inflammatory therapies in heart failure is still debated, since trials of anti-inflammatory agents in this setting have pointed out controversial results. On the contrary, established treatments of heart failure, including ß-blockers, renin-angiotensin system antagonists, and aldosterone-receptor blockers seem able to act by modulating cytokine expression, suggesting a new role for these molecules in guiding heart failure therapy. Therefore, the binomial topic of heart failure and inflammation still has a number of fields not completely explored: our aim is to update current knowledge and future perspectives.

Adaptive immunity, inflammation, and cardiovascular complications in type 1 and type 2 diabetes mellitus.

Diabetes mellitus (DM) is a pandemics that affects more than 170 million people worldwide, associated with increased mortality and morbidity due to coronary artery disease (CAD). In type 1 (T1) DM, the main pathogenic mechanism seems to be the destruction of pancreatic ß -cells mediated by autoreactive T-cells resulting in chronic insulitis, while in type 2 (T2) DM primary insulin resistance, rather than defective insulin production due to ß -cell destruction, seems to be the triggering alteration. In our study, we investigated the role of systemic inflammation and T-cell subsets in T1- and T2DM and the possible mechanisms underlying the increased cardiovascular risk associated with these diseases.

Human epicardium-derived cells fuse with high efficiency with skeletal myotubes and differentiate toward the skeletal muscle phenotype: a comparison study with stromal and endothelial cells.

Recent studies have underscored a role for the epicardium as a source of multipotent cells. Here, we investigate the myogenic potential of adult human epicardium-derived cells (EPDCs) and analyze their ability to undergo skeletal myogenesis when cultured with differentiating primary myoblasts. Results are compared to those obtained with mesenchymal stromal cells (MSCs) and with endothelial cells, another mesodermal derivative. We demonstrate that EPDCs spontaneously fuse with pre-existing myotubes with an efficiency that is significantly higher than that of other cells. Although at a low frequency, endothelial cells may also contribute to myotube formation. In all cases analyzed, after entering the myotube, nonmuscle nuclei are reprogrammed to express muscle-specific genes. The fusion competence of nonmyogenic cells in vitro parallels their ability to reconstitute dystrophin expression in mdx mice. We additionally show that vascular cell adhesion molecule 1 (VCAM1) expression levels of nonmuscle cells are modulated by soluble factors secreted by skeletal myoblasts and that VCAM1 function is required for fusion to occur. Finally, treatment with interleukin (IL)-4 or IL-13, two cytokines released by differentiating myotubes, increases VCAM1 expression and enhances the rate of fusion of EPDCs and MSCs, but not that of endothelial cells.