Secretory products from epicardial adipose tissue of patients with type 2 diabetes mellitus induce cardiomyocyte dysfunction

Apolipoprotein J protects cardiomyocytes from lipid-mediated inflammation and cytotoxicity induced by the epicardial adipose tissue of diabetic patients

Diabetic patients present increased volume and functional alterations in epicardial adipose tissue (EAT). We aimed to analyze EAT from type 2 diabetic patients and the inflammatory and cytotoxic effects induced on cardiomyocytes. Furthermore, we analyzed the cardioprotective role of apolipoprotein J (apoJ). EAT explants were obtained from nondiabetic patients (ND), diabetic patients without coronary disease (DM), and DM patients with coronary disease (DM-C) after heart surgery. Morphological characteristics and gene expression were evaluated. Explants were cultured for 24 h and the content of nonesterified fatty acids (NEFA) and sphingolipid species in secretomes was evaluated by lipidomic analysis. Afterwards, secretomes were added to AC16 human cardiomyocytes for 24 h in the presence or absence of cardioprotective molecules (apoJ and HDL). Cytokine release and apoptosis/necrosis were assessed by ELISA and flow cytometry. The EAT from the diabetic samples showed altered expression of genes related to lipid accumulation, insulin resistance, and inflammation. The secretomes from the DM samples presented an increased ratio of pro/antiatherogenic ceramide (Cer) species, while those from DM-C contained the highest concentration of saturated NEFA. DM and DM-C secretomes promoted inflammation and cytotoxicity on AC16 cardiomyocytes. Exogenous Cer16:0, Cer24:1, and palmitic acid reproduced deleterious effects in AC16 cells. These effects were attenuated by exogenous apoJ. Diabetic secretomes promoted inflammation and cytotoxicity in cardiomyocytes. This effect was exacerbated in the secretomes of the DM-C samples. The increased content of specific NEFA and ceramide species seems to play a key role in inducing such deleterious effects, which are attenuated by apoJ.

Association of epicardial adipose tissue with early structural and functional cardiac changes in Type 2 diabetes

BACKGROUND

Dysregulated epicardial adipose tissue (EAT) may contribute to the development of heart failure in Type 2 diabetes (T2D). This study aimed to evaluate the associations between EAT volume and composition with imaging markers of subclinical cardiac dysfunction in people with T2D and no prevalent cardiovascular disease.

METHODS

Prospective case-control study enrolling participants with and without T2D and no known cardiovascular disease. Two hundred and fifteen people with T2D (median age 63 years, 60 % male) and thirty-nine non-diabetics (median age 59 years, 62 % male) were included. Using computed tomography (CT), total EAT volume and mean CT attenuation, as well as, low attenuation (Hounsfield unit range -190 to -90) EAT volume were quantified by a deep learning method and volumes indexed to body surface area. Associations with cardiac magnetic resonance-derived left ventricular (LV) volumes and strain indices were assessed using linear regression.

RESULTS

T2D participants had higher LV mass/volume ratio (median 0.89 g/mL [0.82-0.99] vs 0.79 g/mL [0.75-0.89]) and lower global longitudinal strain (GLS; 16.1 ± 2.3 % vs 17.2 ± 2.2 %). Total indexed EAT volume correlated inversely with mean CT attenuation. Low attenuation indexed EAT volume was 2-fold higher (18.8 cm3/m2 vs. 9.4 cm3/m2, p < 0.001) in T2D and independently associated with LV mass/volume ratio (ß = 0.002, p = 0.01) and GLS (ß = -0.03, p = 0.03).

CONCLUSIONS

Higher EAT volumes seen in T2D are associated with a lower mean CT attenuation. Low attenuation indexed EAT volume is independently, but only weakly, associated with markers of subclinical cardiac dysfunction in T2D.

Impact of empagliflozin on insulin needs in patients with heart failure and diabetes: An EMPEROR-Pooled analysis

AIM

To assess the effect of empagliflozin on patients with comorbid heart failure (HF) and diabetes with or without baseline insulin, and to study the impact of empagliflozin on insulin requirements over time.

MATERIALS AND METHODS

We performed a post-hoc analysis of pooled patient-level data from two cardiovascular outcomes trials of empagliflozin in HF (EMPEROR-Reduced and EMPEROR-Preserved trials). We undertook a subgroup analysis stratified by baseline insulin use, including all patients with diabetes. The studied endpoints included the primary composite endpoint of first hospitalization for HF or cardiovascular death, rate of decline of estimated glomerular filtration rate, composite renal outcome and rates of sustained insulin initiation.

RESULTS

Among 4794 patients with diabetes, 1333 (658 in empagliflozin, 675 in placebo) were using insulin at baseline. The treatment effect of empagliflozin on the primary endpoint was consistent irrespective of insulin use [no insulin, hazard ratio 0.74, 95% confidence interval (CI) 0.63-0.86; using insulin, hazard ratio 0.81, 95% CI 0.66-1.00, pinteraction = .49], as was the effect on the rate of decline of the estimated glomerular filtration rate (pinteraction = .75). There was no effect of empagliflozin on the composite renal outcome in patients using or not using insulin (pinteraction = .30). Among patients not using insulin at baseline, those randomized to empagliflozin initiated insulin less frequently throughout the follow-up period compared with those receiving placebo (2.6% vs. 3.8%, odds ratio 0.66, 95% CI 0.50-0.88).

CONCLUSIONS

Empagliflozin exerts a consistent benefit on cardiovascular outcomes and renal function decline, irrespective of baseline insulin use, and reduces the need for sustained insulin initiation in patients with HF and diabetes.

Left atrial cardiomyopathy: Pathophysiological insights, assessment methods and clinical implications

Atrial cardiomyopathy is defined as any complex of structural, architectural, contractile or electrophysiological changes affecting atria, with the potential to produce clinically relevant manifestations. Most of our knowledge about the mechanistic aspects of atrial cardiomyopathy is derived from studies investigating animal models of atrial fibrillation and atrial tissue samples obtained from individuals who have a history of atrial fibrillation. Several noninvasive tools have been reported to characterize atrial cardiomyopathy in patients, which may be relevant for predicting the risk of incident atrial fibrillation and its related outcomes, such as stroke. Here, we provide an overview of the pathophysiological mechanisms involved in atrial cardiomyopathy, and discuss the complex interplay of these mechanisms, including aging, left atrial pressure overload, metabolic disorders and genetic factors. We discuss clinical tools currently available to characterize atrial cardiomyopathy, including electrocardiograms, cardiac imaging and serum biomarkers. Finally, we discuss the clinical impact of atrial cardiomyopathy, and its potential role for predicting atrial fibrillation, stroke, heart failure and dementia. Overall, this review aims to highlight the critical need for a clinically relevant definition of atrial cardiomyopathy to improve treatment strategies.

Pathophysiology and clinical relevance of atrial myopathy

Atrial myopathy is a condition that consists of electrical, structural, contractile, and autonomic remodeling of the atria and is the substrate for development of atrial fibrillation, the most common arrhythmia. Pathophysiologic mechanisms driving atrial myopathy are inflammation, oxidative stress, atrial stretch, and neurohormonal signals, e.g., angiotensin-II and aldosterone. These mechanisms initiate the structural and functional remodeling of the atrial myocardium. Novel therapeutic strategies are being developed that target the pathophysiologic mechanisms of atrial myopathy. In this review, we will discuss the pathophysiology of atrial myopathy, as well as diagnostic and therapeutic strategies.

The Role of Epicardial Adipose Tissue in Acute Coronary Syndromes, Post-Infarct Remodeling and Cardiac Regeneration

Epicardial adipose tissue (EAT) is a fat deposit surrounding the heart and located under the visceral layer of the pericardium. Due to its unique features, the contribution of EAT to the pathogenesis of cardiovascular and metabolic disorders is extensively studied. Especially, EAT can be associated with the onset and development of coronary artery disease, myocardial infarction and post-infarct heart failure which all are significant problems for public health. In this article, we focus on the mechanisms of how EAT impacts acute coronary syndromes. Particular emphasis was placed on the role of inflammation and adipokines secreted by EAT. Moreover, we present how EAT affects the remodeling of the heart following myocardial infarction. We further review the role of EAT as a source of stem cells for cardiac regeneration. In addition, we describe the imaging assessment of EAT, its prognostic value, and its correlation with the clinical characteristics of patients.

Exercise-Dependent Modulation of Immunological Response Pathways in Endurance Athletes With and Without Atrial Fibrillation

BACKGROUND

Atrial fibrillation (AF) is a common arrhythmia characterized by uncoordinated atrial electrical activity. Lone AF occurs in the absence of traditional risk factors and is frequently observed in male endurance athletes, who face a 2- to 5-fold higher risk of AF compared with healthy, moderately active males. Our understanding of how endurance exercise contributes to the pathophysiology of lone AF remains limited. This study aimed to characterize the circulating protein fluctuations during high-intensity exercise as well as explore potential biomarkers of exercise-associated AF.

METHODS AND RESULTS

A prospective cohort of 12 male endurance cyclists between the ages of 40 and 65 years, 6 of whom had a history of exercise-associated AF, were recruited to participate using a convenience sampling method. The circulating proteome was subsequently analyzed using multiplex immunoassays and aptamer-based proteomics before, during, and after an acute high-intensity endurance exercise bout to assess temporality and identify potential markers of AF. The endurance exercise bout resulted in significant alterations to proteins involved in immune modulation (eg, growth/differentiation factor 15), skeletal muscle metabolism (eg, α-actinin-2), cell death (eg, histones), and inflammation (eg, interleukin-6). Subjects with AF differed from those without, displaying modulation of proteins previously known to have associations with incident AF (eg, C-reactive protein, insulin-like growth factor-1, and angiopoietin-2), and also with proteins having no previous association (eg, tapasin-related protein and α2-Heremans-Schmid glycoprotein).

CONCLUSIONS

These findings provide insights into the proteomic response to acute intense exercise, provide mechanistic insights into the pathophysiology behind AF in athletes, and identify targets for future study and validation.

Epicardial Adipose Tissue: A Precise Biomarker for Cardiovascular Risk, Metabolic Diseases, and Target for Therapeutic Interventions

Epicardial adipose tissue (EAT) is located between the heart muscle and visceral pericardium, where it has direct contact with coronary blood vessels. Elevated thickness of this tissue can induce local inflammation affecting the myocardium and the underlying coronary arteries, contributing to various cardiovascular diseases such as coronary artery disease, atrial fibrillation, or heart failure with preserved ejection fraction. Recent studies have identified EAT thickness as a simple and reliable biomarker for certain cardiovascular outcomes. Examples include the presence of atherosclerosis, incident cardiovascular disease (CVD) in individuals with type 2 diabetes mellitus (T2DM), and the prevalence of atrial fibrillation. Furthermore, EAT measurements can help to identify patients with a higher risk of developing metabolic syndrome. Since the EAT thickness can be easily measured using echocardiography, such examinations could serve as a useful and cost-effective preventive tool for assessing cardiovascular health. This review also summarizes therapeutical interventions aimed at reducing EAT. Reducing EAT thickness has been shown to be possible through pharmacological, surgical, or lifestyle-change interventions. Pharmaceutical therapies, including thiazolidinediones, glucagon-like peptide 1-receptor agonists, sodium-glucose cotransporter 2 inhibitors, dipeptidyl peptidase-4 inhibitors, and statins, have been shown to influence EAT thickness. Additionally, EAT thickness can also be managed more invasively through bariatric surgery, or noninvasively through lifestyle changes to diet and exercise routines.

Epicardial fat and ventricular arrhythmias

The arrhythmogenic role of epicardial adipose tissue (EAT) in atrial arrhythmias is well established, but its effect on ventricular arrhythmias has been significantly less investigated. Since ventricular arrhythmias are thought to cause 75%-80% of cases of sudden cardiac death, this is not a trivial issue. We provide an overview of clinical data as well as experimental and molecular data linking EAT to ventricular arrhythmias, attempting to dissect possible mechanisms and indicate future directions of research and possible clinical implications. However, despite a wealth of data indicating the role of epicardial and intramyocardial fat in the induction and propagation of ventricular arrhythmias, unfortunately there is currently no direct evidence that indeed EAT triggers arrhythmia or can be a target for antiarrhythmic strategies.

Heart failure with preserved ejection fraction and atrial fibrillation: clinical management in the context of recent therapeutic advances in heart failure and electrophysiology

Heart failure with preserved ejection fraction (HFpEF) and atrial fibrillation (AF) have emerged as major age-related epidemics within cardiology. Both conditions carry overlapping symptomatology, and delineating between AF and HFpEF from a diagnostic standpoint is challenging as echocardiographic and biomarker assessments used to diagnose HFpEF may be impacted by AF. Indeed, these two conditions are commonly found in the same individual, so much so that AF has been used in proposed diagnostic criteria for HFpEF. The frequent concomitant presence of these two conditions is associated with poorer quality of life, exertional capacity, as well as increased risk for decompensated heart failure and all-cause mortality. Though these deleterious effects of AF in HFpEF patients are well described, we currently have only a superficial understanding of the complex interplay between these two conditions. Preliminary studies on intervening in AF in HFpEF are very small, with mixed data on whether modifying the natural history of AF can lead to improvement in heart failure (HF) outcomes in HFpEF. In this review, we will describe the clinical implications of carrying both cardiovascular conditions, address recent advances in HFpEF and AF, and highlight preliminary studies targeted at reduction of effects associated with AF burden in HFpEF.

Epicardial adipose tissue, metabolic disorders, and cardiovascular diseases: recent advances classified by research methodologies

Epicardial adipose tissue (EAT) is located between the myocardium and visceral pericardium. The unique anatomy and physiology of the EAT determines its great potential in locally influencing adjacent tissues such as the myocardium and coronary arteries. Classified by research methodologies, this study reviews the latest research progress on the role of EAT in cardiovascular diseases (CVDs), particularly in patients with metabolic disorders. Studies based on imaging techniques demonstrated that increased EAT amount in patients with metabolic disorders is associated with higher risk of CVDs and increased mortality. Then, in-depth profiling studies indicate that remodeled EAT may serve as a local mediator of the deleterious effects of cardiometabolic conditions and plays a crucial role in CVDs. Further, in vitro coculture studies provided preliminary evidence that the paracrine effect of remodeled EAT on adjacent cardiomyocytes can promote the occurrence and progression of CVDs. Considering the important role of EAT in CVDs, targeting EAT might be a potential strategy to reduce cardiovascular risks. Several interventions have been proved effective in reducing EAT amount. Our review provides valuable insights of the relationship between EAT, metabolic disorders, and CVDs, as well as an overview of the methodological constructs of EAT-related studies.

Radiomics of pericardial fat: a new frontier in heart failure discrimination and prediction

OBJECTIVES

To use pericardial adipose tissue (PAT) radiomics phenotyping to differentiate existing and predict future heart failure (HF) cases in the UK Biobank.

METHODS

PAT segmentations were derived from cardiovascular magnetic resonance (CMR) studies using an automated quality-controlled model to define the region-of-interest for radiomics analysis. Prevalent (present at time of imaging) and incident (first occurrence after imaging) HF were ascertained using health record linkage. We created balanced cohorts of non-HF individuals for comparison. PyRadiomics was utilised to extract 104 radiomics features, of which 28 were chosen after excluding highly correlated ones (0.8). These features, plus sex and age, served as predictors in binary classification models trained separately to detect (1) prevalent and (2) incident HF. We tested seven modeling methods using tenfold nested cross-validation and examined feature importance with explainability methods.

RESULTS

We studied 1204 participants in total, 297 participants with prevalent (60 ± 7 years, 21% female) and 305 with incident (61 ± 6 years, 32% female) HF, and an equal number of non-HF comparators. We achieved good discriminative performance for both prevalent (voting classifier; AUC: 0.76; F1 score: 0.70) and incident (light gradient boosting machine: AUC: 0.74; F1 score: 0.68) HF. Our radiomics models showed marginally better performance compared to PAT area alone. Increased PAT size (maximum 2D diameter in a given column or slice) and texture heterogeneity (sum entropy) were important features for prevalent and incident HF classification models.

CONCLUSIONS

The amount and character of PAT discriminate individuals with prevalent HF and predict incidence of future HF.

CLINICAL RELEVANCE STATEMENT

This study presents an innovative application of pericardial adipose tissue (PAT) radiomics phenotyping as a predictive tool for heart failure (HF), a major public health concern. By leveraging advanced machine learning methods, the research uncovers that the quantity and characteristics of PAT can be used to identify existing cases of HF and predict future occurrences. The enhanced performance of these radiomics models over PAT area alone supports the potential for better personalised care through earlier detection and prevention of HF.

KEY POINTS

•PAT radiomics applied to CMR was used for the first time to derive binary machine learning classifiers to develop models for discrimination of prevalence and prediction of incident heart failure. •Models using PAT area provided acceptable discrimination between cases of prevalent or incident heart failure and comparator groups. •An increased PAT volume (increased diameter using shape features) and greater texture heterogeneity captured by radiomics texture features (increased sum entropy) can be used as an additional classifier marker for heart failure.

Major impact of vitamin D3 deficiency and supplementation on left ventricular torsional mechanics during dobutamine stress in uncomplicated type 2 diabetes

BACKGROUND AND AIMS

Hypovitaminosis D is associated with the risk of diabetic complications. Its role in diabetic-related cardiac abnormalities remain poorly understood. We aimed therefore to evaluate the effect of vitamin D deficiency and supplementation on early left ventricular (LV) dysfunction in vitamin D deficient patients with uncomplicated T2D.

METHODS AND RESULTS

Sixty-three consecutive T2D patients who had a diagnosis of vitamin D3 were prospectively recruited and allocated into 2 groups (25(OH)D < 20 ng/mL: VDD, >20 ng/mL VDND). Twenty-eight of them with 25(OH)D < 20 ng/mL benefited from a 3-month supplementation. At baseline and follow-up, after conventional echocardiography including evaluation of epicardial adipose tissue (EAT), both LV longitudinal (LS) and circumferential (CS) strains and rotation/twist mechanics were evaluated at rest and during dobutamine (DOB) stress. After treatment, T2D patients successfully normalized their 25(OH)D levels. The strongest associations between vitamin D deficiency and supplementation with LV myocardial function were noticed for torsional mechanics indexes under DOB. EAT correlated significantly (p < 0.01) with baseline 25(OH)D and was reduced after supplementation. Significant correlations were obtained between these 2 parameters with twist or apical rotation at baseline (p < 0.01) and between their delta changes at follow-up (p < 0.01) under DOB. Significant improvements in LS and CS (p < 0.05) under DOB were also underlined at follow-up, with major enhancements noticed in the apical region (p < 0.01) of the LV.

CONCLUSIONS

This study provides the first evidences of the potential of vitamin D supplementation as an efficient prophylactic strategy to alleviate the progression of myocardial dysfunction in asymptomatic patients with uncomplicated T2D.

CLINICALTRIALS

NCT03437421.

Sirtuin1, not NAMPT, possesses anti-inflammatory effects in epicardial, pericardial and subcutaneous adipose tissue in patients with CHD

BACKGROUND

Inflammation in cardiac adipose tissue (AT) is associated with atherosclerosis. We investigated whether the epicardial-, pericardial and pre-sternal subcutaneous AT (EAT, PAT and SAT) expression of Sirtuin1 (SIRT1) and nicotinamide phosphoribosyl transferase (NAMPT) are involved in the inflammatory process in coronary heart disease (CHD), and potentially associated to nod-like receptor family pyrin domain containing 3 (NLRP3) inflammasome-related markers, macrophage polarization markers, cell markers and the cardiometabolic profile.

METHODS

In this cohort study performed between 2016 and 2018, EAT, PAT and SAT biopsies were retrieved from 52 CHD patients (77% men, median age 67) undergoing open-chest coronary artery bypass grafting (CABG), and 22 patients (50% men, median age 69) undergoing aortic valve replacement serving as controls. AT samples were snap-frozen at - 80 °C until RNA extraction and AT expression of actual markers, relatively quantified by PCR. Circulating SIRT1 and NAMPT were measured with Enzyme-linked immunosorbent assays (ELISAs). Non-parametric statistical tests were mainly used, including Friedman's test coupled to Wilcoxon signed-rank test and Spearman Correlation.

RESULTS

SIRT1 and NAMPT levels were similar in CHD and controls. In CHD, SIRT1 and NAMPT were inter-correlated in all AT compartments (r = 0.37-0.56, p < 0.01, all), and differently expressed between compartments, with the highest expression in SAT, significantly different from EAT (p < 0.01, both). Circulating SIRT1 and NAMPT levels were inversely associated (r = - 0.32, p = 0.024). In EAT and SAT, SIRT1 expression was inversely associated with IL-18 (r = - 0.43 and r = - 0.38, p < 0.01, both), whereas NAMPT expression was positively associated with the NLRP3 inflammasome-related markers in all compartments (r = 0.37-0.55, p < 0.01, all). While SIRT1 and NAMPT correlated to nitric oxide synthase 2 (NOS2), especially in SAT (r = 0.50-0.52, p ≤ 0.01, both), SIRT1 expression was related to endothelial cells, and NAMPT to macrophages. SIRT1 levels were correlated to weight and waist (r = 0.32 and r = 0.38, p < 0.03, both) and inversely to triglycerides and glycated haemoglobin (HbA1c) (r = - 0.33-- 0.37, p < 0.03, all), the latter positively correlated to NAMPT concentration (r = 0.39, p = 0.010).

CONCLUSION

The study indicates that targeting SIRT1, with its anti-inflammatory properties, may be a novel anti-inflammatory strategy in preventing atherosclerosis and CHD progression. NAMPT may be an early player in AT inflammation, mediating/reflecting a pro-inflammatory state.

TRIAL REGISTRATION

Registration: Clinicaltrials.gov ID: NCT02760914, registered the 5th of February 2016, http://clinicaltrials.gov/NCT02760914.

Epicardial adipose tissue and cardiac lipotoxicity: A review

Epicardial adipose tissue (EAT) has morphological and physiological contiguity with the myocardium and coronary arteries, making it a visceral fat deposit with some unique properties. Under normal circumstances, EAT exhibits biochemical, mechanical, and thermogenic cardioprotective characteristics. Under clinical processes, epicardial fat can directly impact the heart and coronary arteries by secreting proinflammatory cytokines via vasocrine or paracrine mechanisms. It is still not apparent what factors affect this equilibrium. Returning epicardial fat to its physiological purpose may be possible by enhanced local vascularization, weight loss, and focused pharmacological therapies. This review centers on EAT's developing physiological and pathophysiological dimensions and its various and pioneering clinical utilities.

Characterizing regional and global effects of epicardial adipose tissue on cardiac systolic and diastolic function

OBJECTIVE

The aim of this retrospective study was to determine whether regional epicardial adipose tissue (EAT) exerts localized effects on adjacent myocardial left ventricular (LV) function.

METHODS

Cardiac magnetic resonance imaging (MRI), echocardiography, dual-energy x-ray absorptiometry, and exercise testing were performed in 71 patients with obesity with elevated cardiac biomarkers and visceral fat. Total and regional (anterior, inferior, lateral, right ventricular) EAT was quantified by MRI. Diastolic function was quantified by echocardiography. MRI was used to quantify regional longitudinal LV strain.

RESULTS

EAT was associated with visceral adiposity (r = 0.47, p < 0.0001) but not total fat mass. Total EAT was associated with markers of diastolic function (early tissue Doppler relaxation velocity [e'], mitral inflow velocity ratio [E/A], early mitral inflow/e' ratio [E/e']), but only E/A remained significant after adjustment for visceral adiposity (r = -0.30, p = 0.015). Right ventricular and LV EAT had similar associations with diastolic function. There was no evidence for localized effects of regional EAT deposition on adjacent regional longitudinal strain.

CONCLUSIONS

There was no association between regional EAT deposition and corresponding regional LV segment function. Furthermore, the association between total EAT and diastolic function was attenuated after adjustment for visceral fat, indicating that systemic metabolic impairments contribute to diastolic dysfunction in high-risk middle-aged adults.

Role of Epicardial Adipose Tissue Secretome on Cardiovascular Diseases

Obesity and insulin resistance are associated with the inflamed and defective adipose tissue (AT) phenotype, and are established risk factors for cardiovascular diseases (CVDs). Extracellular vesicles (EVs) are a heterogeneous group of cell-derived lipid membrane vesicles involved in the onset and development of many pathologies, including insulin resistance, diabetes, and CVDs. The inflammation associated with overweight and obesity triggers the transition of the AT secretome from healthy to pathological, with a consequent increased expression of pro-inflammatory mediators. Epicardial adipose tissue (EAT) is a specialized fat depot that surrounds the heart, in direct contact with the myocardium. Recently, the role of EAT in regulating the physiopathology of many heart diseases has been increasingly explored. In particular, the EAT phenotype and derived EVs have been associated with the onset and exacerbation of CVDs. In this review, we will focus on the role of the AT secretome in the case of CVDs, and will discuss the beneficial effects of EVs released by AT as promising therapeutic candidates.

Epicardial Fat in Heart Failure with Preserved Ejection Fraction: Bad Actor or Just Lying Around?

Heart failure with preserved ejection fraction (HFpEF) is increasingly recognised to be strongly associated with obesity and abnormalities in fat distribution. Epicardial fat has been associated with abnormal haemodynamics in HFpEF, with potential for direct mechanical effects on the heart causing constriction-like physiology and local myocardial remodelling effects from secretion of inflammatory and profibrotic mediators. However, patients with epicardial fat generally have more systemic and visceral adipose tissue making determination of causality between epicardial fat and HFpEF complex. In this review, we will summarise the evidence for epicardial fat being either directly causal in HFpEF pathogenesis or merely being a correlate of worse systemic inflammatory and generalised adiposity. We will also discuss therapies that directly target epicardial fat and may have potential for treating HFpEF and elucidating the independent role of epicardial fat in its pathogenesis.

Echocardiographic Association of Epicardial Adipose Tissue with Ascending Aorta Elasticity in Patients with Type 2 Diabetes Mellitus

Epicardial adipose tissue (EAT) is an emerging cardiovascular risk factor located between the myocardium and visceral pericardium. In order to investigate the association between EAT and ascending aorta elasticity in patients with type 2 diabetes mellitus (T2DM), we prospectively enrolled a total of 135 T2DM patients and 63 age- and gender-matched non-T2DM controls in this study. They all underwent transthoracic echocardiography to measure EAT thickness and ascending aorta inner diameters which were used to calculate ascending aorta elastic parameters: compliance (C), distensibility (D), strain (S), stiffness index (SI), and Peterson's elastic modulus (EM). We found that the values of C, D, and S were significantly lower, while SI, EM, and EAT thickness were significantly higher in T2DM patients compared with non-T2DM controls. Compared with T2DM patients with EAT < 5 mm group, C, D, and S were significantly reduced, SI and EM were significantly increased in T2DM patients with EAT ≥ 5 mm group (all P < .05). Bivariate correlation and multivariate linear regression analysis revealed that EAT was independently associated with ascending aorta elasticity. Our findings suggest that thickened EAT in patients with T2DM is associated with ascending aorta elasticity, independent of blood glucose.

Relationship between epicardial adipose tissue attenuation and coronary artery disease in type 2 diabetes mellitus patients

BACKGROUND AND AIMS

High epicardial adipose tissue (EAT) attenuation is a key characteristic of adipose tissue dysfunction and associated with coronary artery disease (CAD). As little is known about the modulation of EAT attenuation by metabolic disorders, we investigated the association between EAT attenuation and CAD risk factors, CAD presence and CAD severity in type 2 diabetes mellitus (T2DM) patients.

METHODS

We included 276 inpatients with T2DM and 305 control patients with normal glucose metabolism (NGM), who underwent cardiac computed tomography angiography (CCTA) and coronary artery calcium (CAC) scoring. EAT attenuation and volume were evaluated by contrast-enhanced CCTA image analysis. Furthermore, segment stenosis scores (SSSs) of the left main coronary artery (LMCA), left anterior descending artery (LAD), left circumflex artery (LCX), right coronary artery (RCA), diagonal/intermediate branch (D/I) and obtuse marginal branch (OM) were calculated to assess CAD severity.

RESULTS

T2DM patients showed higher significant CAC scores, coronary plaque prevalence, total SSSs and LMCA-SSSs, LAD-SSSs, LCX-SSSs, RCA-SSSs and D/I-SSSs compared with NGM controls. In contrast to NGM controls, EAT volume was significantly increased in T2DM patients, whereas EAT attenuation was similar. In T2DM patients, EAT attenuation was associated with discrete CAD risk factors, the presence of coronary and triple-vessel plaques, as well as LAD-SSSs, LCX-SSSs, RCA-SSSs and total SSSs. In addition, EAT attenuation was only associated with the total SSS of calcified plaques, but not with noncalcified plaques.

CONCLUSION

In T2DM patients, high EAT attenuation is associated with the presence and severity of CAD in general and with coronary stenosis caused by calcified plaques in particular.

Effect of sex, age and body measurements on heart weight, atrial, ventricular, valvular and sub-epicardial fat measurements of the normal heart

AIMS

Descriptive morphological studies of the normal heart are lacking. Previous autopsy studies have focused mainly on heart weight. We characterize the normal heart by providing normal dimensions of the atria, ventricles, valves and sub-epicardial fat, comparing the findings in terms of sex, age and body measurements.

METHODS

From 3602 referrals to our cardiovascular pathology unit, pathological criteria used for the classification of a morphologically normal heart were a weight of below 500 grams in males, and below 400 grams in females. Diseased hearts were excluded on anatomical and histological evaluation.

RESULTS

We diagnosed 1062 morphologically normal hearts. Mean age at death was 34±12, with a male predominance (701, 66%). Age was similar in females and males (35±13 vs 34±12). Females had a significantly lower heart weight (285±55 vs 374±64). Sex was an independent predictor of most measurements. The atrial and ventricular cavities were significantly larger in males. All ventricular measurements of muscle thickness were larger in males. All valvular circumferences were larger in males. In contrast, sub-epicardial fat was significantly thicker in females in 6 of 7 regions. This is the first study to provide a calculator to give expected values according to sex, age, height and weight.

CONCLUSIONS

Major differences between the sexes exist in the morphologically normal heart. These variations should be considered when assessing cardiac structure in imaging for risk stratification and diagnosis in the cardiomyopathies, as well as in treatment outcomes.

Reduction of cardiac adipose tissue volume with short-term empagliflozin treatment in patients with type 2 diabetes: A substudy from the SIMPLE randomized clinical trial

OBJECTIVE

Ectopic accumulation of cardiac adipose tissue volume (CAT) has been associated with cardiac remodelling and cardiac dysfunction in type 2 diabetes and may be a future therapeutic target. In this substudy from the SIMPLE-trial, we investigated short-term empagliflozin therapy's effects on CAT in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Between 4 April 2017 and 11 May 2020, we randomized 90 patients with type 2 diabetes and established or high risk of cardiovascular disease to 25 mg empagliflozin or placebo for 13 weeks. The substudy focused on change in CAT evaluated by images acquired during ⁸² Rubidium-positron emissions tomography/computed tomography. The analysis included 78 patients who had at least one scan. Furthermore, we report on the relation to the concurrent effects on left ventricular mass, end-diastolic volume and end-systolic volume, body composition and glucometabolic status.

RESULTS

Mean ± SD baseline CAT was 258.5 ± 117.9 ml. Empagliflozin reduced CAT after 13 weeks by 12.41 ml [95% CI (-23.83 to -0.99), p = .034] as compared with placebo. Similarly, left ventricular mass [-5.16 g, 95% CI (-8.80 to -1.52), p = .006], end-diastolic volume and end-systolic volume decreased with empagliflozin. In addition, significant improvements were observed in body composition, with reduced total fat mass, and in measures of glucose and lipid metabolism. However, no correlation was observed between changes in CAT and changes in cardiac parameters and change in CAT appeared mediated primarily by concurrent change in weight.

CONCLUSIONS

Empagliflozin provides an early reduction of CAT; however, no association was observed with concurrent changes in cardiac volumetrics.

Emerging Therapy for Diabetic Cardiomyopathy: From Molecular Mechanism to Clinical Practice

Diabetic cardiomyopathy is characterized by abnormal myocardial structure or performance in the absence of coronary artery disease or significant valvular heart disease in patients with diabetes mellitus. The spectrum of diabetic cardiomyopathy ranges from subtle myocardial changes to myocardial fibrosis and diastolic function and finally to symptomatic heart failure. Except for sodium–glucose transport protein 2 inhibitors and possibly bariatric and metabolic surgery, there is currently no specific treatment for this distinct disease entity in patients with diabetes. The molecular mechanism of diabetic cardiomyopathy includes impaired nutrient-sensing signaling, dysregulated autophagy, impaired mitochondrial energetics, altered fuel utilization, oxidative stress and lipid peroxidation, advanced glycation end-products, inflammation, impaired calcium homeostasis, abnormal endothelial function and nitric oxide production, aberrant epidermal growth factor receptor signaling, the activation of the renin–angiotensin–aldosterone system and sympathetic hyperactivity, and extracellular matrix accumulation and fibrosis. Here, we summarize several important emerging treatments for diabetic cardiomyopathy targeting specific molecular mechanisms, with evidence from preclinical studies and clinical trials.

Epicardial adipose tissue thickness is associated with reduced peak oxygen consumption and systolic reserve in patients with type 2 diabetes and normal heart function

AIM

To investigate the impact of epicardial adipose tissue (EAT) thickness on cardiopulmonary performance in patients with type 2 diabetes (T2D) and normal heart function.

MATERIALS AND METHODS

We analysed EAT thickness in subjects with T2D and normal biventricular systo-diastolic functions undergoing a maximal cardiopulmonary exercise test combined with stress echocardiography, speckle tracking and pulmonary function assessment, as well as serum N-terminal pro B-type natriuretic peptide (NT-proBNP).

RESULTS

In the 72 subjects enrolled, those with EAT thickness above the median (> 5 mm) showed higher body fat mass, smaller indexed left ventricular dimensions and marginally reduced diastolic function variables at rest. Higher EAT thickness was associated with lower peak oxygen uptake (VO_2peak 17.1 ± 3.6 vs. 21.0 ± 5.7 ml/min/kg, P = .001), reduced systolic reserve (ΔS' 4.6 ± 1.6 vs. 5.8 ± 2.5 m/s, P = .02) and higher natriuretic peptides (NT-proBNP 64 [29-165] vs. 31 [26-139] pg/ml, P = .04), as well as chronotropic insufficiency and impaired heart rate recovery. Ventilatory variables and peripheral oxygen extraction were not different between groups. EAT was independently associated with VO_2peak and linearly and negatively correlated with peak heart rate, heart rate recovery, workload, VO₂ at the anaerobic threshold and at peak, and cardiac power output, and was directly correlated with natriuretic peptides.

CONCLUSION

Higher EAT thickness in T2D is associated with worse cardiopulmonary performance and multiple traits of subclinical cardiac systolic dysfunction.

Increased Epicardial Adipose Tissue (EAT), Left Coronary Artery Plaque Morphology, and Valvular Atherosclerosis as Risks Factors for Sudden Cardiac Death from a Forensic Perspective

Background: In sudden cardiac deaths (SCD), visceral adipose tissue has begun to manifest interest as a standalone cardiovascular risk factor. Studies have shown that epicardial adipose tissue can be seen as a viable marker of coronary atherosclerosis. This study aimed to evaluate, from a forensic perspective, the correlation between body mass index (BMI), heart weight, coronary and valvular atherosclerosis, left ventricular morphology, and the thickness of the epicardial adipose tissue (EAT) in sudden cardiac deaths, establishing an increased thickness of EAT as a novel risk factor. Methods: This is a retrospective case−control descriptive study that included 80 deaths that were autopsied, 40 sudden cardiac deaths, and 40 control cases who hanged themselves and had unknown pathologies prior to their death. In all the autopsies performed, the thickness of the epicardial adipose tissue was measured in two regions of the left coronary artery, and the left ventricular morphology, macro/microscopically quantified coronary and valvular atherosclerosis, and weight of the heart were evaluated. Results: This study revealed a higher age in the SCD group (58.82 ± 9.67 vs. 53.4 ± 13.00; p = 0.03), as well as a higher incidence in females (p = 0.03). In terms of heart and coronary artery characteristics, there were higher values of BMI (p = 0.0009), heart weight (p < 0.0001), EAT of the left circumflex artery (LCx) (p < 0.0001), and EAT of the left anterior descending artery (LAD) (p < 0.0001). In the multivariate analysis, a high baseline value of BMI (OR: 4.05; p = 0.004), heart weight (OR: 5.47; p < 0.001), EAT LCx (OR: 23.72; p < 0.001), and EAT LAD (OR: 21.07; p < 0.001) were strong independent predictors of SCD. Moreover, age over 55 years (OR: 2.53; p = 0.045), type Vb plaque (OR: 17.19; p < 0.001), mild valvular atherosclerosis (OR: 4.88; p = 0.002), and moderate left ventricle dilatation (OR: 16.71; p = 0.008) all act as predictors of SCD. Conclusions: The data of this research revealed that higher baseline values of BMI, heart weight, EAT LCx, and EAT LAD highly predict SCD. Furthermore, age above 55 years, type Vb plaque, mild valvular atherosclerosis, and left ventricle dilatation were all risk factors for SCD.

Depot-specific adipose tissue modulation by SGLT2 inhibitors and GLP1 agonists mediates their cardioprotective effects in metabolic disease

Sodium-glucose transporter-2 inhibitors (SGLT-2i) and glucagon-like peptide 1 (GLP-1) receptor agonists are newer antidiabetic drug classes, which were recently shown to decrease cardiovascular (CV) morbidity and mortality in diabetic patients. CV benefits of these drugs could not be directly attributed to their blood glucose lowering capacity possibly implicating a pleotropic effect as a mediator of their impact on cardiovascular disease (CVD). Particularly, preclinical and clinical studies indicate that SGLT-2i(s) and GLP-1 receptor agonists are capable of differentially modulating distinct adipose pools reducing the accumulation of fat in some depots, promoting the healthy expansion of others, and/or enhancing their browning, leading to the suppression of the metabolically induced inflammatory processes. These changes are accompanied with improvements in markers of cardiac structure and injury, coronary and vascular endothelial healing and function, vascular remodeling, as well as reduction of atherogenesis. Here, through a summary of the available evidence, we bring forth our view that the observed CV benefit in response to SGLT-2i or GLP-1 agonists therapy might be driven by their ameliorative impact on adipose tissue inflammation.

Serum CD14 concentration is associated with obesity and insulin resistance in non-diabetic individuals

OBJECTIVE

CD14 is a lipopolysaccharide-binding protein that serves as a marker of monocytes. The role of circulating CD14 in patients with obesity without diabetes remains unknown. Here, we characterized the relationships between serum CD14 concentration and metabolic parameters related to diabetes and obesity.

METHODS

We performed an observational, prospective case-control study. Eighty participants were evaluated: 26 drug-naïve patients with type 2 diabetes mellitus and 54 healthy individuals. We compared the circulating CD14 concentration and metabolic parameters of the participants with and without diabetes.

RESULTS

The circulating CD14 concentration did not significantly differ between the two groups, but was lower in participants with obesity than in lean controls. No significant associations existed between CD14 concentration and metabolic parameters in the participants with diabetes, but in those without diabetes, the circulating CD14 concentration significantly negatively correlated with body mass index; waist circumference; the concentrations of fasting insulin, 2-hour post-load glucose, 2-h post-load insulin, and low-density lipoprotein-cholesterol; homeostasis model of assessment (HOMA) of insulin resistance; and HOMA beta-cell function.

CONCLUSIONS

This is the first study to show associations of serum CD14 concentration with metabolic parameters in non-diabetic individuals. Circulating CD14 may represent a useful biomarker of metabolic dysfunction in non-diabetic individuals.

Correlation analysis of epicardial adipose tissue and ventricular myocardial strain in Chinese amateur marathoners using cardiac magnetic resonance

Background

The volume of epicardial adipose tissue (EAT) is associated with an increased incidence of cardiovascular disease (CVD); however, only a few studies have examined its effect on the myocardial function of endurance in athletes. The association between the EAT and the variation of myocardial function is still unclear in amateur marathoners. Consequently, by using some sedentary individuals as the control, this study aims to evaluate the correlation between the EAT volume and the myocardial strain in the left and right ventricles of Chinese amateur marathoners by cardiac magnetic resonance (CMR).

Methods

A total of 30 amateur marathoners were included as the exercise group and 20 sedentary people as a control group. All participants received the cardiac magnetic resonance (CMR) to measure the left and right ventricular end-diastolic volume, end-systolic volume and volume index, stroke volume and index, cardiac output index, ejection fraction and myocardial mass, the EAT volume, global radial, circumferential, and longi-tudinal strains, and the strain rates of left and right ventricular myocardium.

Results

There was a significant difference in the EAT volume (EATV) index between the exercise group and the control group (26.82±11.76ml/m² vs 37.82±17.15ml/m², P = 0.01). Results from the multivariate linear regression analysis showed that BMI (standardized β = 0.458; P < 0.001) had an independent positive correlation with the EATV index. The EATV index was negatively correlated with the left ventricular global radial strain (GRS) (r = -0.505; P = 0.004) in the exercise group, while it is negatively correlated with right ventricular GRS (r = -0.492; P = 0.027) and positively correlated with global longitudinal strain (GLS) (r = 0.601; P = 0.005) in the control group. In the exercise group, the multivariate linear regression analysis showed that the EATV index (standardized β = -0.429; P = 0.021) was an independent determinant of the left ventricular GRS, and being a male (standardized β = 0.396; P = 0.029) was an independent determinant of the right ventricular GLS.

Conclusion

The EATV index is independently correlated with the left ventricular GRS in the amateur Chinese marathoners, also, the amateur marathon reduces the EATV index and increases the left ventricular myocardial mass, which consequently reduces the adverse effects on myocardial function.

Additive effects of type 2 diabetes and metabolic syndrome on left ventricular torsion and linear deformation abnormalities during dobutamine stress echocardiography

Objective

The interplay between metabolic syndrome (MS) and type 2 diabetes (T2D) on regional myocardial mechanics and the potential additional effects of their combination remain poorly understood. In this context, we evaluated left ventricular (LV) torsion and linear deformation at rest and under dobutamine (DB) stress in patients with T2D, MS or both.

Methods

Thirty-nine T2D patients without MS (T2D), 37 MS patients free from T2D (MS), 44 patients with both T2D and MS (T2D-MS group) and 38 healthy patients (control group) were prospectively recruited. Speckle-tracking echocardiography (STE) was conducted at rest and low dose DB to evaluate LV myocardial longitudinal (LS) as well as circumferential (CS) strain and early diastolic strain rate (LSrd, CSrd) and twist-untwist mechanics.

Results

At rest, MS, T2D and controls presented with similar resting LS and LSrd while significant lower values were obtained in T2D-MS compared to controls. DB revealed reduced LS, LSrd, CS and CSrd in MS and T2D groups compared to controls. In T2-MS, the decline in LS and LSrd established at rest was exacerbated under DB. Stress echocardiography revealed also lower basal rotation and subsequently lower twist in MS and T2D patients compared to controls. T2D-MS showed major impairments of apical rotation and twist under DB stress, with values significantly lower compared to the 3 other groups. From stepwise multiple linear regression analysis, epicardial adipose tissue for Δ (rest to DB) LS, numbers of MS factors for Δ CS and Δ Twist emerged as major independent predictors.

Conclusion

These results demonstrate synergic and additive effects of T2D and MS on LV torsion and linear deformation abnormalities in asymptomatic patients with metabolic diseases. They also highlight the usefulness of speckle tracking echocardiography under DB stress in detecting multidirectional myocardial mechanics impairments that can remain barely detectable at rest, such as in isolated T2D or MS patients.

Putative protective effects of sodium-glucose cotransporter 2 inhibitors on atrial fibrillation through risk factor modulation and off-target actions: potential mechanisms and future directions

Atrial fibrillation, the most common cardiac arrhythmia, results in substantial morbidity and mortality related to its increased risks of stroke, heart failure, and impaired cognitive function. The incidence and prevalence of atrial fibrillation in the general population is rising, making atrial fibrillation treatment and management of its risk factors highly relevant clinical targets. One well-studied risk factor for the development of atrial fibrillation is diabetes mellitus. Inhibitors of sodium-glucose cotransporter 2 (SGLT2), common medications used to treat diabetes mellitus, have been observed to decrease the incidence of atrial fibrillation. This review discusses the SGLT2 and its role in glucose homeostasis, molecules inhibiting the transporter, possible physiological mechanisms responsible for the decreased incident atrial fibrillation in patients treated with SGLT2 inhibitors and proposes mechanistic studies to further our understanding of the biological processes involved.

Epicardial Adipose Tissue as an Independent Cardiometabolic Risk Factor for Coronary Artery Disease

During the last decades, visceral adiposity has been at the forefront of scientific research because of its complex role in the pathogenesis of cardiovascular diseases. Epicardial adipose tissue (EAT) is the visceral lipid compartment between the myocardium and the visceral pericardium. Due to their unobstructed anatomic vicinity, epicardial fat and myocardium are nourished by the same microcirculation. It is widely known that EAT serves as an energy lipid source and thermoregulator for the human heart. In addition to this, epicardial fat exerts highly protective effects since it releases a great variety of anti-inflammatory molecules to the adjacent cardiac muscle. Taking into account the unique properties of human EAT, it is undoubtedly a key factor in cardiac physiology since it facilitates complex heart functions. Under pathological circumstances, however, epicardial fat promotes coronary atherosclerosis in a variety of ways. Therefore, the accurate estimation of epicardial fat thickness and volume could be utilized as an early detecting method and future medication target for coronary artery disease (CAD) elimination. Throughout the years, several therapeutic approaches for dysfunctional human EAT have been proposed. A balanced healthy diet, aerobic and anaerobic physical activity, bariatric surgery, and pharmacological treatment with either traditional or novel antidiabetic and antilipidemic drugs are some of the established medical approaches. In the present article, we review the current knowledge regarding the anatomic and physiological characteristics of epicardial fat. In addition to this, we describe the pathogenic mechanisms which refer to the crosstalk between epicardial fat alteration and coronary arterial atherosclerosis development. Lastly, we present both lifestyle and pharmacological methods as possible treatment options for EAT dysfunction. 

Association between epicardial adipose tissue and left ventricular function in type 2 diabetes mellitus: Assessment using two-dimensional speckle tracking echocardiography

BACKGROUND AND AIMS

Epicardial adipose tissue (EAT) is the visceral fat between the myocardium and the visceral pericardium. Dysfunctional EAT can cause cardiovascular diseases. The aim of this study was to investigate the association between EAT and left ventricular function in type 2 diabetes mellitus (T2DM) patients by two-dimensional speckle tracking echocardiography (2D-STE).

METHODS

We prospectively enrolled 116 T2DM patients who were divided into two groups according to their left ventricular global longitudinal strain (GLS): 53 with GLS <18% and 63 with GLS ≥18%. The thickness of EAT was measured as the echo-free space between the free wall of the right ventricle and the visceral layer of pericardium at end-systole. LV systolic function was evaluated by GLS measured by 2D-STE. LV diastolic function was defined as the ratio of the early diastolic transmitral flow velocity (E) to average mitral annular velocity (e¯).

RESULTS

Compared with patients with GLS ≥18% group, the age, body mass index (BMI), waist circumference (WC), systolic blood pressure (SBP), diastolic blood pressure (DBP), low-density lipoprotein cholesterol (LDL-C), glycosylated hemoglobinA1c (HbA1c), E/e¯, and thickness of EAT were higher in patients with GLS <18% group (all P < 0.05). Multivariate linear regression analysis revealed that the thickness of EAT was independently associated with left ventricular GLS and E/e¯.

CONCLUSIONS

Thickened EAT is associated with impaired left ventricular function in T2DM patients. To investigate the association between EAT and left ventricular function can help us gain a deeper understanding of the pathogenesis of impaired cardiac function in T2DM patients.

Multiparametric CMR imaging of myocardial structure and function changes in diabetic mini-pigs with preserved LV function: a preliminary study

Background

The purpose of this study is to dynamically monitor the myocardial structure and function changes in diabetic mini-pigs by 1.5 T cardiac magnetic resonance.

Methods

Three male mini-pigs underwent cardiac magnet resonance (CMR) imaging, and histologic examination. T1-mapping was acquired at basal, mid and apical segments. CMR feature-tracking (CMR-FT) is used to quantify left ventricle global longitudinal (LVGLS), circumferential (LVGCS) and radial strain (LVGRS). Epicardial adipose tissue (EAT) was evaluated using a commercially available software.

Results

Left ventricular mass (LVM), myocardial native T1 value, extracellular volume (ECV) value and EAT were increased gradually after 6 months of modeling, while LVGLS decreased gradually after 6 months of modeling (LVM: 24.5 (23.4, 26.7) vs. 42.7 (41.4, 44.6) g/m², p < 0.001; Native T1: 1005.5 (992.6, 1010.7) vs. 1028.7 (1015.5, 1035.6) ms, p = 0.041; EAT: 16.1 (14.5, 18.2) vs. 24.6 (20.8, 26.9) mL, p = 0.020; ECV: 21.4 (20.2, 23.9) vs. 28.9 (26.7, 30.3) %, p = 0.011; LVGLS: − 22.8 (− 21.4, − 23.9) vs. − 17.4 (− 17.2, − 19.2)%, p = 0.008). The diffuse myocardial interstitial fibrosis was found in histology samples.

Conclusion

The progressive impairments in LV structure and myocardial deformation occurs in diabetic mini-pigs. T1 mapping and CMR-FT technology are promising to monitor abnormal changes of diabetic myocardium in the early stage of diabetic cardiomyopathy.

Management of Type 2 Diabetes in Stage C Heart Failure with Reduced Ejection Fraction

Type 2 diabetes is an increasingly common comorbidity of stage C heart failure with reduced ejection fraction (HFrEF). The two diseases are risk factors for each other and can bidirectionally independently worsen outcomes. The regulatory requirement of cardiovascular outcomes trials for antidiabetic agents has led to an emergence of novel therapies with robust benefits in heart failure, and clinicians must now ensure they are familiar with the management of patients with concurrent diabetes and stage C HFrEF. This review summarises the current evidence for the management of type 2 diabetes in stage C HFrEF, recapitulating data from landmark heart failure trials regarding the use of guideline-directed medical therapy for heart failure in patients with diabetes. It also provides a preview of upcoming clinical trials in these populations.

The Cardiomyocyte in Heart Failure with Preserved Ejection Fraction—Victim of Its Environment?

Heart failure (HF) with preserved left ventricular ejection fraction (HFpEF) is becoming the predominant form of HF. However, medical therapy that improves cardiovascular outcome in HF patients with almost normal and normal systolic left ventricular function, but diastolic dysfunction is missing. The cause of this unmet need is incomplete understanding of HFpEF pathophysiology, the heterogeneity of the patient population, and poor matching of therapeutic mechanisms and primary pathophysiological processes. Recently, animal models improved understanding of the pathophysiological role of highly prevalent and often concomitantly presenting comorbidity in HFpEF patients. Evidence from these animal models provide first insight into cellular pathophysiology not considered so far in HFpEF disease, promising that improved understanding may provide new therapeutical targets. This review merges observation from animal models and human HFpEF disease with the intention to converge cardiomyocytes pathophysiological aspects and clinical knowledge.

Metformin: Expanding the Scope of Application-Starting Earlier than Yesterday, Canceling Later

Today the area of application of metformin is expanding, and a wealth of data point to its benefits in people without carbohydrate metabolism disorders. Already in the population of people leading an unhealthy lifestyle, before the formation of obesity and prediabetes metformin smooths out the adverse effects of a high-fat diet. Being prescribed at this stage, metformin will probably be able to, if not prevent, then significantly reduce the progression of all subsequent metabolic changes. To a large extent, this review will discuss the proofs of the evidence for this. Another recent important change is a removal of a number of restrictions on its use in patients with heart failure, acute coronary syndrome and chronic kidney disease. We will discuss the reasons for these changes and present a new perspective on the role of increasing lactate in metformin therapy.

Dysregulated Epicardial Adipose Tissue as a Risk Factor and Potential Therapeutic Target of Heart Failure with Preserved Ejection Fraction in Diabetes

Cardiovascular (CV) disease and heart failure (HF) are the leading cause of mortality in type 2 diabetes (T2DM), a metabolic disease which represents a fast-growing health challenge worldwide. Specifically, T2DM induces a cluster of systemic metabolic and non-metabolic signaling which may promote myocardium derangements such as inflammation, fibrosis, and myocyte stiffness, which represent the hallmarks of heart failure with preserved ejection fraction (HFpEF). On the other hand, several observational studies have reported that patients with T2DM have an abnormally enlarged and biologically transformed epicardial adipose tissue (EAT) compared with non-diabetic controls. This expanded EAT not only causes a mechanical constriction of the diastolic filling but is also a source of pro-inflammatory mediators capable of causing inflammation, microcirculatory dysfunction and fibrosis of the underlying myocardium, thus impairing the relaxability of the left ventricle and increasing its filling pressure. In addition to representing a potential CV risk factor, emerging evidence shows that EAT may guide the therapeutic decision in diabetic patients as drugs such as metformin, glucagon-like peptide‑1 (GLP-1) receptor agonists and sodium-glucose cotransporter 2 inhibitors (SGLT2-Is), have been associated with attenuation of EAT enlargement.

Expression profiles of long noncoding and messenger RNAs in epicardial adipose tissue derived from patients with coronary atherosclerosis

BACKGROUND

Given its close anatomical location to the heart and its endocrine properties, attention on epicardial adipose tissue (EAT) has increased.

OBJECTIVE

This study investigated the expression profiles of long noncoding RNAs (lncRNAs) and messenger RNAs (mRNAs) in EAT derived from patients with coronary artery disease (CAD).

METHODS

EAT samples from 8 CAD and 8 non-CAD patients were obtained during open-heart surgery. The expression of lncRNAs and mRNAs in each EAT sample was investigated using microarray analysis and further verified using reverse transcription-quantitative polymerase chain reaction.

RESULTS

Overall, 1,093 differentially expressed mRNAs and 2,282 differentially expressed lncRNAs were identified in EAT from CAD vs non-CAD patients. Analysis using Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes showed that these differentially expressed genes were mainly enriched in various inflammatory, immune, and metabolic processes. They were also involved in osteoclast differentiation, B cell receptor and adipocytokine signaling, and insulin resistance pathways. Additionally, lncRNA-mRNA and lncRNA-target pathway networks were built to identify potential core genes (e.g. Lnc-CCDC68-2:1, AC010148.1, NONHSAT104810) involved in atherosclerosis pathogenesis.

CONCLUSION

In summary, lncRNA and mRNA profiles in EAT were markedly different between CAD and non-CAD patients. Our study identifies several potential key genes and pathways that may participate in atherosclerosis development.

Targeting Epicardial Fat in Obesity and Diabetes Pharmacotherapy

Epicardial adipose tissue surrounds and infiltrates the heart. Epicardial fat displays unique anatomic, genetic, and biomolecular properties. People with obesity and in particular, those with abdominal obesity and associated type 2 diabetes mellitus, have an increased amount of epicardial adipose tissue (EAT). Epicardial fat works well as therapeutic target due to its fast-responding metabolism, organ fat specificity, and easy measurability. Epicardial fat responds to thiazolidinediones (TZD), glucagon-like peptide 1-receptor agonists (GLP1A), sodium-glucose cotransporter 2 inhibitors (SGLT2i), dipeptidyl peptidase-4 inhibitors (DPP4i), and statins. Modulating epicardial fat morphology and genetic profile with targeted pharmacological agents suggests novel strategies in the pharmacotherapy of diabetes and obesity.

Inter-Organ Crosstalk in the Development of Obesity-Associated Insulin Resistance

The epidemics of obesity and type 2 diabetes have led to intensive investigation of the underlying mechanisms of these diseases and their main complications such as cardiovascular diseases and non-alcoholic fatty liver disease. This search has contributed to better understand how organs and tissues communicate with each other in the so-called inter-organ crosstalk. Adipose tissue, the liver, or skeletal muscle can actively release secreted factors termed "organokines" which can interact with other distant targets in complex networks. More recently, other novel mediators of inter-organ crosstalk such as extracellular vesicles and their non-traditional cargoes as miRNAs and lncRNAs are gaining importance and represent potential therapeutic targets. In the present chapter we summarize some of the current knowledge on inter-organ communication with a focus on adipose tissue-released factors and their modulation on other organs and tissues like pancreas, liver, skeletal muscle, the cardiovascular system, and the gut in the context of obesity and its progression to insulin resistance. We also provide a perspective on mediators of inter-organ crosstalk as potential therapeutic targets.

Heart failure with preserved ejection fraction: An alternative paradigm to explain the clinical implications of atrial fibrillation

Atrial fibrillation (AF) is associated with exercise intolerance, stroke, and all-cause mortality. However, whether this can be solely attributable to the arrhythmia itself or alternative mechanisms remains controversial. Heart failure with preserved ejection (HFpEF) commonly coexists with AF and may contribute to the poor outcomes associated with AF. Indeed, several invasive hemodynamic studies have confirmed that patients with AF are at increased risk of underlying HFpEF and that the presence of HFpEF may have important prognostic implications in these patients.

Mechanistically, AF and HFpEF are closely linked. Both conditions are driven by the presence of common cardiovascular risk factors and are associated with left atrial (LA) myopathy, characterized by mechanical and electrical dysfunction. Progressive worsening of this left atrial (LA) myopathy is associated with both increased AF burden and worsening HFpEF. In addition, there is growing evidence to suggest that worsening LA myopathy is associated with poorer outcomes in both conditions and that reversal of the LA myopathy could improve outcomes. In this review article, we will present the epidemiologic and mechanistic evidence underlying the common coexistence of AF and HFpEF, discuss the importance of a progressive LA myopathy in the pathogenesis of both conditions, and review the evidence from important invasive hemodynamic studies. Finally, we will review the prognostic implications of HFpEF in patients with AF and discuss the relative merits of AF burden reduction vs HFpEF reduction in improving outcomes of patients with AF and HFpEF.

Epicardial and Pericardial Adiposity Without Myocardial Steatosis in Cushing Syndrome

CONTEXT

Cardiovascular disease is the leading cause of death in patients with Cushing syndrome. Cortisol excess and adverse metabolic profile could increase cardiac fat, which can subsequently impair cardiac structure and function.

OBJECTIVE

We aimed to evaluate cardiac fat mass and distribution in patients with Cushing syndrome.

METHODS

In this prospective, cross-sectional study, 23 patients with Cushing syndrome and 27 control individuals of comparable age, sex, and body mass index were investigated by cardiac magnetic resonance imaging and proton spectroscopy. Patients were explored before and after biochemical disease remission. Myocardial fat measured by the Dixon method was the main outcome measure. The intramyocardial triglyceride/water ratio measured by spectroscopy and epicardial and pericardial fat volumes were secondary outcome measures.

RESULTS

No difference was found between patients and controls in intramyocardial lipid content. Epicardial fat mass was increased in patients compared to controls (30.8 g/m2 [20.4-34.8] vs 17.2 g/m2 [13.1-23.5], P < .001). Similarly, pericardial fat mass was increased in patients compared to controls (28.3 g/m2 [17.9-38.0] vs 11.4 g/m2 [7.5-19.4], P = .003). Sex, glycated hemoglobin A1c, and the presence of hypercortisolism were independent determinants of epicardial fat. Pericardial fat was associated with sex, impaired glucose homeostasis and left ventricular wall thickness. Disease remission decreased epicardial fat mass without affecting pericardial fat.

CONCLUSION

Intramyocardial fat stores are not increased in patients with Cushing syndrome, despite highly prevalent metabolic syndrome, suggesting increased cortisol-mediated lipid consumption. Cushing syndrome is associated with marked accumulation of epicardial and pericardial fat. Epicardial adiposity may exert paracrine proinflammatory effects promoting cardiomyopathy.

A histological study of the atria in patients with isolated rheumatic mitral regurgitation with and without atrial fibrillation

BACKGROUND

There is a high incidence of atrial fibrillation (AF) in patients with isolated rheumatic mitral regurgitation (MR). The histopathologic changes in the atria of patients with isolated rheumatic MR with and without AF are unknown.

OBJECTIVES

We aimed to determine the histological findings in patients with isolated severe rheumatic MR with and without AF.

METHODS

Patients with severe isolated rheumatic MR undergoing valve replacement surgeries underwent endocardial biopsies from right atrial appendage, left atrial appendage, right free wall, left free wall, left posterior wall, and mitral valve. Group I consisted of patients in sinus rhythm (SR), and Group II included patients with AF. We analyzed and compared these 10 histological features in the biopsies of patients in Groups I and II.

RESULTS

Of the 25 patients, 12 were in Group I and 13 in Group II. In Group I, patients had severe myocyte hypertrophy (60% vs. 18%, p = .04) that was significantly more in the right atrium (22.7% vs. 11.4%, p = .059). Interstitial adipose tissue deposition was more common in Group I (30% vs. 25%, p = .06). Interstitial fibrosis was evenly distributed at all sites without significant difference between the two groups. Group II patients had a higher prevalence and severity of vacuolar degeneration (91% vs. 60%, p = .09).

CONCLUSIONS

Patients with isolated severe rheumatic MR and AF have more vacuolar degeneration in the atrial tissue. Patients with SR have myocyte hypertrophy and interstitial adipose tissue deposition. Interstitial fibrosis is uniformly distributed in patients in SR and AF.

Inflammation in Metabolic Cardiomyopathy

Overlapping pandemics of lifestyle-related diseases pose a substantial threat to cardiovascular health. Apart from coronary artery disease, metabolic disturbances linked to obesity, insulin resistance and diabetes directly compromise myocardial structure and function through independent and shared mechanisms heavily involving inflammatory signals. Accumulating evidence indicates that metabolic dysregulation causes systemic inflammation, which in turn aggravates cardiovascular disease. Indeed, elevated systemic levels of pro-inflammatory cytokines and metabolic substrates induce an inflammatory state in different cardiac cells and lead to subcellular alterations thereby promoting maladaptive myocardial remodeling. At the cellular level, inflammation-induced oxidative stress, mitochondrial dysfunction, impaired calcium handling, and lipotoxicity contribute to cardiomyocyte hypertrophy and dysfunction, extracellular matrix accumulation and microvascular disease. In cardiometabolic patients, myocardial inflammation is maintained by innate immune cell activation mediated by pattern recognition receptors such as Toll-like receptor 4 (TLR4) and downstream activation of the NLRP3 inflammasome and NF-κB-dependent pathways. Chronic low-grade inflammation progressively alters metabolic processes in the heart, leading to a metabolic cardiomyopathy (MC) phenotype and eventually to heart failure with preserved ejection fraction (HFpEF). In accordance with preclinical data, observational studies consistently showed increased inflammatory markers and cardiometabolic features in patients with HFpEF. Future treatment approaches of MC may target inflammatory mediators as they are closely intertwined with cardiac nutrient metabolism. Here, we review current evidence on inflammatory processes involved in the development of MC and provide an overview of nutrient and cytokine-driven pro-inflammatory effects stratified by cell type.

Potential role of epicardial adipose tissue in coronary artery endothelial cell dysfunction in type 2 diabetes

Cardiovascular disease is the most prevalent cause of morbidity and mortality in diabetes. Epicardial adipose tissue (EAT) lies in direct contact with the myocardium and coronary arteries and can influence cardiac (patho) physiology through paracrine signaling pathways. This study hypothesized that the proteins released from EAT represent a critical molecular link between the diabetic state and coronary artery endothelial cell dysfunction. To simulate type 2 diabetes-associated metabolic and inflammatory status in an ex vivo tissue culture model, human EAT samples were treated with a cocktail composed of high glucose, high palmitate, and lipopolysaccharide (gplEAT) and were compared with control EAT (conEAT). Compared to conEAT, gplEAT showed a markedly increased gene expression profile of proinflammatory cytokines, corroborating EAT inflammation, a hallmark feature observed in patients with type 2 diabetes. Luminex assay of EAT-secretome identified increased release of various proinflammatory cytokines, including tumor necrosis factor-alpha (TNF-alpha), interferon-alpha 2 (IFNA2), interleukin 1 beta (IL1B), interleukin 5 (IL5), interleukin 13 (IL13), and CCL5, among others, in response to high glucose, high palmitate, and lipopolysaccharide. Conditioned culture media was used to collect the concentrated proteins (CPs). In response to gplEAT-CPs, human coronary artery endothelial cells (HCAECs) exhibited an inflammatory endothelial cell phenotype, featuring a significantly increased gene expression of proinflammatory cytokines and cell surface expression of VCAM-1. Moreover, gplEAT-CPs severely decreased Akt-eNOS signaling, nitric oxide production, and angiogenic potential of HCAECs, when compared with conEAT-CPs. These findings indicate that EAT inflammation may play a key role in coronary artery endothelial cell dysfunction in type 2 diabetes.

Effect of SGLT2-Inhibitors on Epicardial Adipose Tissue: A Meta-Analysis

(1) Sodium-glucose cotransporter-2 inhibitors (SGLT2-i) reduce adipose tissue and cardiovascular events in patients with type 2 diabetes (T2D). Accumulation of epicardial adipose tissue (EAT) is associated with increased cardio-metabolic risks and obstructive coronary disease events in patients with T2D. (2) We performed a systematic review and meta-analysis of SGLT2-i therapy on T2D patients, reporting data on changes in EAT after searching the PubMed/MEDLINE, Embase, Science Direct, Scopus, Google Scholar, and Cochrane databases. A random effects or fixed effects model meta-analysis was then applied. (3) Results: A total of three studies (n = 64 patients with SGLT2-i, n = 62 with standard therapy) were included in the final analysis. SGLT2 inhibitors reduced EAT (SMD: -0.82 (-1.49; -0.15); p < 0.0001). An exploratory analysis showed that HbA1c was significantly reduced with SGLT2-i use, while body mass index was not significantly reduced with this drug. (4) Conclusions: This meta-analysis suggests that the amount of EAT is significantly reduced in T2D patients with SGLT2-i treatment.

COVID-19 and Obesity: Role of Ectopic Visceral and Epicardial Adipose Tissues in Myocardial Injury

In March 2020, the WHO declared coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a global pandemic. Obesity was soon identified as a risk factor for poor prognosis, with an increased risk of intensive care admissions and mechanical ventilation, but also of adverse cardiovascular events. Obesity is associated with adipose tissue, chronic low-grade inflammation, and immune dysregulation with hypertrophy and hyperplasia of adipocytes and overexpression of pro-inflammatory cytokines. However, to implement appropriate therapeutic strategies, exact mechanisms must be clarified. The role of white visceral adipose tissue, increased in individuals with obesity, seems important, as a viral reservoir for SARS-CoV-2 via angiotensin-converting enzyme 2 (ACE2) receptors. After infection of host cells, the activation of pro-inflammatory cytokines creates a setting conducive to the "cytokine storm" and macrophage activation syndrome associated with progression to acute respiratory distress syndrome. In obesity, systemic viral spread, entry, and prolonged viral shedding in already inflamed adipose tissue may spur immune responses and subsequent amplification of a cytokine cascade, causing worse outcomes. More precisely, visceral adipose tissue, more than subcutaneous fat, could predict intensive care admission; and lower density of epicardial adipose tissue (EAT) could be associated with worse outcome. EAT, an ectopic adipose tissue that surrounds the myocardium, could fuel COVID-19-induced cardiac injury and myocarditis, and extensive pneumopathy, by strong expression of inflammatory mediators that could diffuse paracrinally through the vascular wall. The purpose of this review is to ascertain what mechanisms may be involved in unfavorable prognosis among COVID-19 patients with obesity, especially cardiovascular events, emphasizing the harmful role of excess ectopic adipose tissue, particularly EAT.

Mechanistic Insights of Empagliflozin in Nondiabetic Patients With HFrEF: From the EMPA-TROPISM Study

OBJECTIVES

The goal of this study was to evaluate the effect of empagliflozin, in addition to optimal medical treatment, on epicardial adipose tissue (EAT), interstitial myocardial fibrosis, and aortic stiffness in nondiabetic patients with heart failure with reduced ejection fraction (HFrEF).

BACKGROUND

Several randomized clinical trials have established the benefits of the inhibitors of the sodium-glucose cotransporter-2 receptor (SGLT2-i) in HFrEF, independent of their hypoglycemic effects. The mechanisms of the benefits of SGLT2-i in HFrEF have not been well defined.

METHODS

This study was a secondary analysis of patients enrolled in the EMPA-TROPISM [ATRU-4] (Are the cardiac benefits of Empagliflozin independent of its hypoglycemic activity?) clinical trial. It was a double-blind, placebo-controlled randomized clinical trial investigating the effect of empagliflozin in nondiabetic patients with HFrEF. Patients underwent cardiac magnetic resonance at baseline and after 6 months. Interstitial myocardial fibrosis was calculated by using T₁ mapping (extracellular volume). Aortic stiffness was calculated by using pulsed wave velocity, and EAT was measured from the cine sequences.

RESULTS

Empagliflozin is associated with significant reductions in EAT volume (-5.14 mL; 95% CI: -8.36 to -1.92) compared with placebo (-0.75 mL; 95% CI: -3.57 to 2.06; P < 0.05); this finding was paralleled by reductions in subcutaneous adipose tissue area (-5.33 cm² [95% CI: -12.61 to 1.95] vs 9.13 cm² [95% CI: -2.72 to 20.99]; P < 0.05). Empagliflozin-treated patients reported a reduction in extracellular volume (-1.25% [±0.56 95% CI] vs 0.24% [±0.57 95% CI]; (P < 0.01)]; specifically, empagliflozin reduced both matrix volume (-7.24 mL [95% CI: -11.59 to -2.91] vs 0.70 mL [95% CI: -0.89 to 2.29]; P < 0.001) and cardiomyocyte volume (-11.08 mL [95% CI: -19.62 to -2.55] vs 0.80 mL [95% CI: -1.96 to 3.55]; P < 0.05). Pulsed wave velocity was also significantly reduced in the empagliflozin group (-0.58 cm/s [95% CI: -0.92 to -0.25] vs 0.60 cm/s [95% CI: 0.14 to 1.06]; P < 0.01). Using proteomics, empagliflozin was associated with a significant reduction in inflammatory biomarkers.

CONCLUSIONS

Empagliflozin significantly improved adiposity, interstitial myocardial fibrosis, aortic stiffness, and inflammatory markers in nondiabetic patients with HFrEF. These results shed new light on the mechanisms of action of the benefits of SGLT2-i. (Are the "Cardiac Benefits" of Empagliflozin Independent of Its Hypoglycemic Activity [ATRU-4] [EMPA-TROPISM]; NCT03485222).