Microbial signature of plaque and gut in acute coronary syndrome

Gut microbiota is an emerging editable cardiovascular risk factor. We aim to investigate gut and coronary plaque microbiota, using fecal samples and angioplasty balloons from patients with acute coronary syndrome (ACS), chronic coronary syndrome (CCS) and control subjects. We examined bacterial communities in gut and coronary plaques by 16S rRNA sequencing and we performed droplet digital PCR analysis to investigate the gut relative abundance of the bacterial genes CutC/CntA involved in trimethylamine N-oxide synthesis. Linear discriminant analysis effect size (LEfSe) at the genus and species levels displayed gut enrichment in Streptococcus, Granulicatella and P. distasonis in ACS compared with CCS and controls; Roseburia, C. aerofaciens and F. prausnitzii were more abundant in controls than in patients. Principal component analysis (PCA) of 41 differentially abundant gut taxa showed a clustering of the three groups. In coronary plaque, LEfSe at the genus level revealed an enrichment of Staphylococcus and Streptococcus in ACS, and Paracoccus in CCS, whereas PCA of 15 differentially abundant plaque taxa exhibited clustering of ACS and CCS patients. CutC and CntA genes were more abundant in ACS and CCS than in controls while no significant difference emerged between ACS and CCS. Our results indicate that ACS and CCS exhibit a different gut and plaque microbial signature, suggesting a possible role of these microbiotas in coronary plaque instability.

Levosimendan for acute right heart failure in COVID-19: another arrow in our quiver?

OBJECTIVE

SARS-CoV-2 infection is associated with a higher risk of acute right heart failure (RHF) due to primary right ventricle (RV) dilation and systemic inflammatory response, which in turn lead to microvascular and cardiomyocytes dysfunction, local hypoxia and multi-organ failure. In this clinical setting, levosimendan could be a viable therapy thanks to its right-heart tropism and its additional pleiotropic properties.

CASE REPORT

We present the case of a 72 years-old man with positive nasopharyngeal swab for SARS-CoV-2 infection, mild pulmonary involvement and clinical signs of new-onset RHF. We started a 12-hour levosimendan cycle to improve RV performance and reduce cardiac filling pressures.

RESULTS

We obtained a net clinical benefit in terms of acute RHF-related signs and symptoms, progressive renal and liver function improvement and concomitant reduction of high-sensitivity C-Reactive Protein and Interleukin-6 (IL-6) levels.

CONCLUSIONS

Acute RHF during SARS-CoV-2 infection could be related to a convergent widespread systemic inflammatory response. Thanks to its anti-inflammatory and anti-remodeling properties, levosimendan might represent a viable therapy in this clinical setting, contributing to the dampening of the inflammatory response.

A Novel Monocyte Subset as a Unique Signature of Atherosclerotic Plaque Rupture

The evaluation of monocyte subset distribution among acute coronary syndrome (ACS) patients according to culprit coronary plaque morphology has never been explored. We evaluated whether there were significant differences in frequency of circulating monocyte subsets isolated from ACS patients according to optical coherence tomography (OCT) investigation of plaque erosion and rupture. We enrolled 74 patients with non-ST-elevation ACS (NSTE-ACS), 21 of them underwent OCT investigation of the culprit coronary plaque and local macrophage infiltration (MØI) assessment. As control, we enrolled 30 chronic coronary syndrome (CCS) patients. We assessed the frequency of monocyte subsets in the whole study population, in reliance on their CD14 and CD16 expression (classical, CM: CD14⁺⁺CD16^–; intermediates, IM: CD14⁺⁺CD16⁺; non-classical, NCM: CD14⁺CD16⁺⁺). Then, we tested the effect of lipopolysaccharide (LPS) (a CD14 ligand) on peripheral blood mononuclear cells (PBMCs) of NSTE-ACS patients, quantifying the inflammatory cytokine levels in cell-culture supernatants. Our data proved that monocyte subsets isolated from NSTE-ACS patients represent a peculiar biological signature of the pathophysiological mechanism lying beneath atherosclerotic plaque with a ruptured fibrous cap (RFC) as compared with plaque erosion. Moreover, the magnitude of LPS-mediated effects on IL-1β, IL-6, and IL-10 cytokine release in cell-culture supernatants appeared to be greater in NSTE-ACS patients with RFC. Finally, we described a fourth monocyte population never explored before in this clinical setting (pre-classical monocytes, PCM: CD14⁺CD16^–) that was prevalent in NSTE-ACS patients as compared with CCS and, especially, in patients with RFC and culprit plaque with MØI.

Takotsubo syndrome: a way to reach a straightforward diagnosis

Background/Introduction

Acute stress-induced cardiomyopathy, also known as Takotsubo Syndrome (TTS), was originally classified as a benign disease. Nowadays, this assumption has changed, especially in its long-term outcome, due to TTS clinical presentation, that often mirrors the acute myocardial infarction (MI) phenotype. Current knowledge already delineate clinical features distinctive of TTS and MI patients, however, diagnosis requires multiple, expansive, and invasive medical examinations. Moreover, concerning the biological panorama, very slight is known and the lack of a tailored therapy is resented. Therefore, a biological profile for this clinical category could provide easier and less invasive diagnostic tools, leading edge towards novel therapeutic pathways.

Purpose

The aim of the study is to perform a biological profile of the TTS group compared to the ST Segment Elevation Myocardial Infarction (STEMI) in order to explore the molecular peculiarities attendant the pathophysiologic mechanisms.

Methods

We performed a gene expression array on two groups of pooled cDNA from peripheral blood mononuclear cells, from TTS (n=11) and STEMI (n=19) patients. We conducted gene expression validations for each enrolled patient through qPCR.

Results

Our preliminary data displayed several differences in gene expression levels of a grand number of cell adhesion signaling molecule between the two groups. As shown in figure 1, three gene were more expressed in TTS group: Nitric Oxide Synthase 3, also known as endothelial NOS (NOS3; p=0.002), Superoxide dismutase 1 (SOD1; p=0.03) and transferrin receptor (TFRC; p=0.005). Meanwhile, five gene displayed a higher expression in STEMI patients compared to TTS: phospholipase A2 Group 7 (PLA2G7; p=0.04), Galectin 8 (LGALS8; p=0.02), Intercellular Adhesion Molecule 1 (ICAM1; p=0.002), Hyaluronidase 2 (HYAL2; p=0.01) and Hyaluronan Receptor (CD44; p=0.0002).

Conclusions

The earliest results of this study led us to focus on fewer genes related to endothelial and oxidative stress pathways. TTS is habitually triggered by intense emotional or physical stress. Indeed, our results showed how TTS patients present higher expression of NOS3, SOD1 and TFRC, all components involved in the oxidative stress pathways. In STEMI patients, top expressed genes, such as HYAL2, CD44 and ICAM1, are all associated with extracellular matrix turnover, likely due to the presence of a stenotic plaque and the consequent endothelial derangement. The uncovering of diagnostic biomarkers in TTS might improve the early, non-invasive, stratification of this group of patients, thus facilitating novel and personalized therapeutics design.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The present study was supported by the Italian National Project Grant PRIN 2017.

Platelet hyaluronidase 2 enrichment in acute coronary syndromes: a conceivable role in monocyte-platelet aggregate formation

Acute Coronary Syndromes (ACS) with plaque erosion display dysregulated hyaluronan metabolism, with increased hyaluronidase-2 (HYAL2) expression. However, the expression and the role of this enzyme on platelets has never been explored. We evaluated the platelet’s HYAL2 (_pltHYAL2) levels on I) stable angina (SA) and II) ACS patients, furtherly sub-grouped in Intact-Fibrous-Cap (IFC) and Ruptured-Fibrous-Cap (RFC), according to Optical Coherence Tomography. We assessed the HYAL2 role through an in vitro model setting of co-cultured monocytes and platelets, before and after treatment with low-molecular-weight hyaluronic acid (HA) as pro-inflammatory stimulus and with or without HYAL2-antibody to inhibit HYAL2 activity. ACS patients exhibit higher _pltHYAL2 levels comparing to SA, with the higher expression for IFC group. The addition of HYAL2-antibody significantly reduced the percentage of monocyte-platelet binding, suggesting that _pltHYAL2 enrichment at the site of the culprit lesion is a key mediator in the systemic thrombo-inflammatory status of ACS presenting with plaque erosion.

Electrocardiographic findings at presentation and clinical outcome in patients with SARS-CoV-2 infection

Aims

The main severe complications of SARS-CoV-2 infection are pneumonia and respiratory distress syndrome. Recent studies, however, reported that cardiac injury, as assessed by troponin levels, is associated with a worse outcome in these patients. No study hitherto assessed whether the simple standard electrocardiogram (ECG) may be helpful for risk stratification in these patients.

Methods and results

We studied 324 consecutive patients admitted to our Emergency Department with a confirmed diagnosis of SARS-CoV-2 infection. Standard 12-lead ECG recorded on admission was assessed for cardiac rhythm and rate, atrioventricular and intraventricular conduction, abnormal Q/QS wave, ST segment and T wave changes, corrected QT interval, and tachyarrhythmias. At a mean follow-up of 31 ± 11 days, 44 deaths occurred (13.6%). Most ECG variables were significantly associated with mortality, including atrial fibrillation (P = 0.002), increasing heart rate (P = 0.002), presence of left bundle branch block (LBBB; P < 0.001), QRS duration (P <0 .001), a QRS duration of ≥110 ms (P < 0.001), ST segment depression (P < 0.001), abnormal Q/QS wave (P = 0.034), premature ventricular complexes (PVCs; P = 0.051), and presence of any ECG abnormality [hazard ratio (HR) 4.58; 95% confidence interval (CI) 2.40–8.76; P < 0.001]. At multivariable analysis, QRS duration (P = 0.002), QRS duration ≥110 ms (P = 0.03), LBBB (P = 0.014) and presence of any ECG abnormality (P = 0.04) maintained a significant independent association with mortality.

Conclusion

Our data show that standard ECG can be helpful for an initial risk stratification of patients admitted for SARS-CoV-2 infectious disease.

From angiotensin-converting enzyme 2 disruption to thromboinflammatory microvascular disease: A paradigm drawn from COVID-19

We concisely review clinical, autopsy, experimental and molecular data of 2019 coronavirus disease (COVID-19). Angiotensin-converting enzyme 2 disruption and thromboinflammatory microangiopathy emerge as distinctive features. Briefly, entry of the virus into microvessels can profoundly disrupt the local renin-angiotensin system, cause endothelial injury, activate the complement cascade and induce powerful thromboinflammatory reactions, involving, in particular, von Willebrand factor, that, if widespread, may lead to microvascular plugging, ischemia and, ultimately, organ failure. We believe the current COVID-19 data consolidate a widely unrecognised paradigm of potentially fatal thromboinflammatory microvascular disease.

Fluid-dynamics and biological features of unstable plaques: different shear stress for different plaques

Background

The use of Optical Coherence Tomography (OCT) in acute coronary syndromes (ACS) allows recognizing ruptured fibrous cap (RFC) and intact fibrous cap (IFC) culprit lesions. The biological differences between them, as recently pointed out in translation studies, highlight different mechanisms for a similar clinical manifestation that might deserve different therapeutic approaches. The relationship between endothelial wall shear stress (WSS) and ACS has been demonstrated, however the differences in WSS features between RFC and IFC have not been elucidated.

Purpose

The aim of this study is to provide a fluid-dynamic and biological description of unstable and stable (SA) plaques, according to OCT analysis.

Methods

We enrolled 10 SA and 20 Non-ST Elevation Myocardial Infarction (NSTEMI)-ACS patients, with IFC (n=10) and RFC (n=10) culprit lesions according to OCT analysis. We performed Real-time PCR primer array on pooled Peripheral Blood Mononuclear Cell (PBMC) for 30 different molecules whose expression is strictly dependent on WSS. High-fidelity 3D-coronary artery models were created for 3 patients per group, applying previously validated methodologies.

Results

Among the groups we found a broad difference in molecular expression (Fig. 1A), with RFC displaying higher levels of molecules involved in vasoconstriction/dilatation (EDN1, NOS3), cellular adhesion (ICAM1), and peptidase inhibition (PI16). A significantly higher WSS was observed in RFC group (p&lt;0.001, Fig 1B and C), with larger variability and larger areas exposed to both low and high WSS (Fig. 1D). Interestingly, the molecules overexpressed in RFC are known to be upregulated by high WSS.

Conclusions

Our data demonstrated that IFC and RFC unstable plaques are associated with different WSS conditions, alongside with the expression of different molecular patterns specifically related to altered WSS. In the era of precision medicine these findings may have relevant therapeutical implications.

Funding Acknowledgement

Type of funding source: None

Plaque instability in acute coronary syndromes: a possible pathogenic role of gut microbial communities

Background

The imbalance between protective and harmful bacteria in the microbial communities leads to a non-physiological condition, known as “dysbiosis”. In the last decade, several studies have suggested that gut microbiota can contribute to the development and progression of various disease including cardiovascular disease through metabolism-mediated pathways. The production and the release of bacterial metabolites, including Trimethylamine N-oxide (TMAO), can affect host health acting to distant organs.

Purpose

The aim of the present study was to explore the gut microbiota and the levels of TMAO in patients with stable angina (SA) and acute coronary syndrome (ACS) with or without elevation of the ST segment, respectively STEMI and NSTEMI, and in control subjects.

Methods

Feces were obtained from ACS (n=31) and SA (n=23) patients and controls (n=24). Genomic DNA was isolated using the QIamp DNA Stool Mini Kit. Samples were subjected to 16S rRNA gene V3–V4 region sequencing by an Illumina MiSeq TM platform. A combination of software packages QIIME and VSEARCH was used to generate a biological observation matrix (BIOM) at different taxonomic levels (from phylum to genus). The BIOM was analysed using the Web-based program MicrobiomeAnalyst. β-diversity between groups was obtained by weighted UniFrac distance metric analysis. Serum TMAO levels were measured with a UPLC-MS/MS mass spectrometry in SA and ACS patients.

Results

β-diversity analysis showed a different bacterial composition in SA and ACS patients and controls ([PERMANOVA] F-value: 1.9706; R-squared: 0.050567; p-value &lt;0.018) (Figure 1A). In particular, analysis between the three groups revealed a significant enrichment of Streptococcus genus in ACS patients (Kruskas Wallis test; p=0.0085) (Figure 1B). Controls and ACS revealed a similar gut microbial composition ([PERMANOVA] F-value: 0.7591; R-squared: 0.014388; p-value &lt;0.61) (Figure 2A); in contrast, controls and SA showed separate clusters according to relative differences in taxonomic composition ([PERMANOVA] F-value: 3.0498; R-squared: 0.064821 p-value &lt;0.006) (Figure 2B). Finally, β-diversity analysis in SA and ACS revealed different microbial communities in the two groups [PERMANOVA] F-value: 2.5103; R-squared: 0.046051; p-value &lt;0.025) (Figure 2C) that could partially explain the severity progression of cardiovascular disease. Serum TMAO levels were higher in STEMI (n=14) as compared to SA and to NSTEMI (n=16) (respectively p=0.016 and p=0.028) (Figure 3).

Conclusion

These results, taken together, suggest that gut microbiota and its derived metabolites might play an essential role in the progression of atherosclerosis and in coronary plaque instability.

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): Linea D1 Università Cattolica del Sacro Cuore

Meta-inflammation in monocytes of patients with Acute Coronary Syndrome

Background

Several studies suggest that an alteration of monocyte metabolism might be implicated in inflammatory diseases. Enhanced glycolysis might be a hallmark of pro-inflammatory monocyte subsets. Improved glycolysis enables the immune cells to generate sufficient ATP and biosynthetic intermediates to carry out its particular effector functions. For macrophages this includes phagocytosis and inflammatory cytokine production. Pyruvate Kinase isozyme M2 (PKM-2) catalyzes the final step of glycolysis producing pyruvate and ATP. Latest studies have shown that a member of Jumonji family (JMJD8) acts as a positive regulator in TNF-induced NF-kB signaling leading to pro-inflammatory pathways in macrophages and is involved in angiogenesis and cellular metabolism through interacting with PKM-2 in endothelial cells.

Purpose

The aims of the study are to assess the expression of the glycolytic key enzyme PKM-2 in CD14+ monocytes obtained from patients with non-ST-elevation myocardial infarction (NSTEMI) or with stable angina (SA). Furthermore, the expression of JMJD8 was evaluated.

Methods

30 patients with NSTEMI and 30 patients with SA were enrolled. Peripheral blood mononuclear cells were obtained from whole blood samples. For cytoplasmatic protein identification, cells were fixed and permeabilized and then incubated with fluorochrome-conjugated mAbs anti-CD14, anti-PKM-2 and anti-JMJD8. For analysis we used Two-tailed Mann-Whitney non parametric Comparison test.

Results

CD14+ monocytes from NSTEMI patients showed reduced expression of the key glycolytic enzyme PKM-2 as compared to CD14+ monocytes from SA patients (p=0.02) (Figure 1). JMJD8 expression in NSTEMI patients is increased compared with SA patients (p=0.02) (Figure 2).

Conclusion

This study introduces a role for immune-metabolism in the immunity dysregulation described in ACS patients and provides novel insights into the mechanisms responsible for coronary instability. Taking their potential interaction into account, our data suggest that in acute setting glycolysis key enzyme PKM2 expression is downregulated. Besides, JMJD8 protein levels increase in NSTEMI patients acting as potential limiting factor of PKM2 function. Moreover, our data propose the potential roles of immune-metabolism to detect novel therapeutic targets, associated with an accurate patient stratification based on immune-metabolic profiles, for prevention and treatment of atherosclerosis, in the perspective of a personalized medicine approach.

Funding Acknowledgement

Type of funding source: Private hospital(s). Main funding source(s): Fondazione Policlinico A. Gemelli

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.

Correlation between CD4+CD28null T lymphocytes, regulatory T cells and plaque rupture: An Optical Coherence Tomography study in Acute Coronary Syndromes

BACKGROUND

A sizeable proportion of patients with Acute Coronary Syndromes (ACS) shows a unique adaptive immune system profile, associated to a worse outcome, characterized by higher CD4⁺CD28^null T-cells, lower regulatory T-cells (Treg) and increased CD4⁺CD28^null/Treg ratio. We sought to investigate the correlation between CD4⁺CD28^null T-cells, Treg, CD4⁺CD28^null/Treg ratio and plaque phenotype as assessed by Optical Coherence Tomography (OCT).

METHODS

Peripheral blood mononuclear cells (PBMC) were collected from 30 Non-ST Elevation Myocardial Infarction (NSTEMI) patients, sub-grouped according to OCT analysis of culprit lesions into two cohorts: Ruptured Fibrous Cap (NSTEMI-RFC, n = 12) and Intact Fibrous Cap (NSTEMI-IFC, n = 18). Stable Angina patients (SA, n = 18) were used as controls. We examined the frequency of CD4⁺CD28^null and Treg (defined as CD4⁺CD25^highCD127^lowFoxp3⁺ T-cells) by flow-cytometry.

RESULTS

CD4⁺CD28^null frequency (median, range) was significantly higher in NSTEMI-RFC patients (17.3%, 12.5-33.8) as compared with NSTEMI-IFC (3.8%, 0.3-14.1) and SA (3%, 0.6-17.7) (P < 0.001 for all comparisons). We also found a higher CD4⁺CD28^null/Treg ratio in NSTEMI-RFC patients (6.6%, 3.7-13.9) than in NSTEMI-IFC (1.6%, 0.3-5.2) and SA (1.2%, 0.3-8.7) (P < 0.001 for all comparisons). Finally, there was an inverse correlation between CD4⁺CD28^null/Treg ratio and cap-thickness (R = -0.44; P = 0.002).

CONCLUSION

Patients with NSTEMI presenting with RFC as culprit lesion at OCT evaluation have a specific perturbation of adaptive immunity, mostly involving CD4⁺CD28^null T- cells and Tregs, as compared with patients with IFC and SA. This specific imbalance of T-cells might play a key role in fibrous cap thinning, predisposing atherosclerotic plaque to rupture.

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.

Where Does Inflammation Fit?

PURPOSE OF REVIEW

This review focuses on the complex relationship between inflammation and the onset of acute coronary syndrome and heart failure.

RECENT FINDINGS

In the last few years, two important lines of research brought new and essential information to light in the pathogenesis of acute coronary syndrome: a) the understanding of the immune mediate mechanisms of inflammation in Ischemic Heart Disease (IHD) and b) evidence that the inflammatory mechanisms associated with atherosclerosis and its complications can be modulated by anti-inflammatory molecules. A large amount of data also suggests that inflammation is a major component in the development and exacerbation of heart failure (HF), in a symbiotic relationship. In particular, recent evidence underlies peculiar aspects of the phenomenon: oxidative stress and autophagy; DAMPS and TLR-4 signaling activation; different macrophages lineage and the contribution of NLRP-3 inflammasome; adaptive immune system. A possible explanation that could unify the pathogenic mechanism of these different conditions is the rising evidence that increased bowel permeability may allow translation of gut microbioma product into the circulation. These findings clearly establish the role of inflammation as the great trigger for two of the major cardiovascular causes of death and morbidity. Further studies are needed, to better clarify the issue and to define more targeted approaches to reduce pathological inflammation while preserving the physiological one.