Drugs That Ameliorate Epicardial Adipose Tissue Inflammation May Have Discordant Effects in Heart Failure With a Preserved Ejection Fraction as Compared With a Reduced Ejection Fraction

Comparative study on the predictive value of TG/HDL-C, TyG and TyG-BMI indices for 5-year mortality in critically ill patients with chronic heart failure: a retrospective study

BACKGROUND

The triglyceride glucose (TyG) index, TyG-body mass index (TyG-BMI), and triglyceride-density lipoprotein cholesterol ratio (TG/HDL-C) are substitute indicators for insulin resistance (IR). This study aimed to compare the predictive value of these indicators for 5-year mortality in critically ill patients with chronic heart failure (CHF).

METHODS

Critically ill patients with CHF were identified from the Multiparameter Intelligent Monitoring in Intensive Care (MIMIC) III and IV databases. The primary outcome was 5-year mortality. The relationship between the three indices and mortality risk was determined using multivariate Cox proportional hazards models, Kaplan-Meier (K‒M) analysis and restricted cubic splines analysis. A receiver operating characteristic (ROC) curve was generated to compare the ability of the three indices to predict mortality. Finally, whether the IR indices would further increase the predictive ability of the basic model including baseline variables with a significance level between survivors and non-survivors was evaluated by ROC curve.

RESULTS

Altogether, 1329 patients with CHF were identified from the databases. Cox proportional hazards models indicated that the TyG index was independently associated with an elevated risk of 5-year mortality (hazard ratio [HR], 1.56; 95% confidence interval [CI] 1.29-1.9), while the TyG-BMI index and TG/HDL-C level were significantly associated with 5-year mortality, with an HR (95% CI) of 1.002 (1.000-1.003) and 1.01 (1.00-1.03), respectively. The K-M analysis revealed that the cumulative incidence of all-cause 5-year death increased with increasing quartiles of the TyG index, TyG-BMI index, or TG/HDL-C ratio. According to the ROC curve, the TyG index outperformed the TyG-BMI and TG/HDL-C ratio at predicting all-cause 5-year mortality (0.608 [0.571-0.645] vs. 0.558 [0.522-0.594] vs. 0.561 [0.524-0.598]). The effect of the TyG index on all-cause mortality was consistent across subgroups, with no significant interaction with randomized factors. Furthermore, adding the TyG index to the basic model for 5-year mortality improved its predictive ability (area under the curve, 0.762 for the basic model vs. 0.769 for the basic model + TyG index); however, the difference was not statistically significant.

CONCLUSION

As continuous variables, all three indices were significantly associated with 5-year mortality risk in critically ill patients with CHF. Although these IR indices did not improve the predictive power of the basic model in patients with CHF, the TyG index appears to be the most promising index (vs. TyG-BMI and TG/HDL-C ratio) for prevention and risk stratification in critically ill patients with CHF.

Epicardial adipose tissue and pericardial constraint in heart failure with preserved ejection fraction

AIMS

Obesity and epicardial adiposity play a role in the pathophysiology of heart failure with preserved ejection fraction (HFpEF), and both are associated with increased filling pressures and reduced exercise capacity. The haemodynamic basis for these observations remains inaccurately defined. We hypothesize that an abundance of epicardial adipose tissue (EAT) within the pericardial sac is associated with haemodynamic signs of pericardial constraint.

METHODS AND RESULTS

HFpEF patients who underwent invasive heart catheterization with simultaneous echocardiography were included. Right atrial pressure (RAP), right ventricular end-diastolic pressure, and pulmonary capillary wedge pressure (PCWP) were invasively measured. The presence of a square root sign on the right ventricular pressure waveform and the RAP/PCWP ratio (surrogate parameters for pericardial constraint) were investigated. EAT thickness alongside the right ventricle was measured on echocardiography. Sixty-four patients were studied, with a mean age of 73 ± 10 years, 64% women, and a mean body mass index (BMI) of 28.6 ± 5.4 kg/m2. In total, 47 patients (73%) had a square root sign. The presence of a square root sign was associated with higher BMI (29.3 vs. 26.7 kg/m2, P = 0.02), higher EAT (4.0 vs. 3.4 mm, P = 0.03), and higher RAP (9 vs. 6 mmHg, P = 0.04). Women had more EAT than men (4.1 vs. 3.5 mm, P = 0.04), despite a comparable BMI. Women with a square root sign had significantly higher EAT (4.3 vs. 3.3 mm, P = 0.02), a higher mean RAP (9 vs. 5 mmHg, P = 0.02), and a higher RAP/PCWP ratio (0.52 vs. 0.26, P = 0.002). In men, such associations were not seen, although there was no significant interaction between men and women (P > 0.05 for all analyses).

CONCLUSIONS

Obesity and epicardial adiposity are associated with haemodynamic signs of pericardial constraint in patients with HFpEF. The pathophysiological and therapeutic implications of this finding need further study.

New Mechanisms to Prevent Heart Failure with Preserved Ejection Fraction Using Glucagon-like Peptide-1 Receptor Agonism (GLP-1 RA) in Metabolic Syndrome and in Type 2 Diabetes: A Review

This review examines the impact of obesity on the pathophysiology of heart failure with preserved ejection fraction (HFpEF) and focuses on novel mechanisms for HFpEF prevention using a glucagon-like peptide-1 receptor agonism (GLP-1 RA). Obesity can lead to HFpEF through various mechanisms, including low-grade systemic inflammation, adipocyte dysfunction, accumulation of visceral adipose tissue, and increased pericardial/epicardial adipose tissue (contributing to an increase in myocardial fat content and interstitial fibrosis). Glucagon-like peptide 1 (GLP-1) is an incretin hormone that is released from the enteroendocrine L-cells in the gut. GLP-1 reduces blood glucose levels by stimulating insulin synthesis, suppressing islet α-cell function, and promoting the proliferation and differentiation of β-cells. GLP-1 regulates gastric emptying and appetite, and GLP-1 RA is currently indicated for treating type 2 diabetes (T2D), obesity, and metabolic syndrome (MS). Recent evidence indicates that GLP-1 RA may play a significant role in preventing HFpEF in patients with obesity, MS, or obese T2D. This effect may be due to activating cardioprotective mechanisms (the endogenous counter-regulatory renin angiotensin system and the AMPK/mTOR pathway) and by inhibiting deleterious remodeling mechanisms (the PKA/RhoA/ROCK pathway, aldosterone levels, and microinflammation). However, there is still a need for further research to validate the impact of these mechanisms on humans.

Classification, Diagnosis, and Treatment of Obesity-Related Heart Diseases

Evidence-based medicine shows that obesity is associated with a wide range of cardiovascular (CV) diseases. Obesity can lead to changes in cardiac structure and function, which can lead to obese cardiomyopathy, subclinical cardiac dysfunction, and even heart failure. It also increases the risk of atrial fibrillation and sudden cardiac death. Many invasive and noninvasive diagnostic methods can detect obesity-related heart disease at an early stage, so that appropriate measures can be selected to prevent adverse CV events. However, studies have shown a protective effect of obesity on clinical outcomes of CV disease, a phenomenon that has been termed the obesity paradox. The "obesity paradox" essentially refers to the fact that the classification of obesity defined by body mass index (BMI) does not consider the impact of obesity heterogeneity on CV disease prognosis, but simply puts subjects with different clinical and biochemical characteristics into the same category. In any case, indicators such as waist-to-hip ratio, ectopic body fat qualitative and quantitative, and CV fitness have been shown to be able to distinguish different CV risks in patients with the same BMI, which is convenient for early intervention in an appropriate way. A multidisciplinary approach, including lifestyle modification, evidence-based generic and novel pharmacotherapy, and surgical intervention, can improve CV outcomes in overweight/obese patients.

Identification of molecular signatures in epicardial adipose tissue in heart failure with preserved ejection fraction

AIMS

The molecular signatures in epicardial adipose tissue (EAT) that contribute to the pathogenesis of heart failure with preserved ejection fraction (HFpEF) are poorly characterized. In this study, we sought to elucidate molecular signatures including genetic transcripts and long non-coding RNAs (lncRNAs) in EAT that might modulate HFpEF development.

METHODS

RNA sequencing (RNA-seq) was performed to identify differentially expressed lncRNAs and mRNAs in EAT samples from patients with HFpEF (n = 5) and without HF (control, n = 5) who underwent coronary artery bypass grafting. The sequencing results were validated using quantitative real-time PCR (qRT-PCR). Bioinformatics analysis (Gene Ontology and Kyoto Encyclopedia of Genes and Genomes) of differentially expressed RNAs was performed to predict enriched functions.

RESULTS

HFpEF patients had higher EAT thickness and NT-proBNP levels than the control group. A total of 64 471 transcripts were detected including 35 395 protein-coding sequences, corresponding to 16 854 genes in EAT. RNA-seq identified a total of 741 dysregulated mRNA transcripts (394 up-regulated and 347 down-regulated) and 334 differentially expressed lncRNA transcripts (222 up-regulated and 112 down-regulated) in the HFpEF group compared with the control group (P < 0.05). qRT-PCR analysis confirmed that two lncRNAs ENST00000561775 (P = 0.0194) and ENST00000519093 (P = 0.027) and an mRNA POSTN (P = 0.003) were differentially expressed. Functional enrichment analysis of the differentially expressed mRNAs suggested their potential roles in immune response involving cytokine interaction and chemokine signalling.

CONCLUSIONS

We are the first group to report on the lncRNA and mRNA landscape in EAT in HFpEF patients. Our study suggests the possible role of lncRNAs in EAT.

Current Insights and Future Directions in the Treatment of Heart Failure with Preserved Ejection Fraction

Heart failure is a clinical syndrome associated with poor quality of life, substantial healthcare resource utilization, and premature mortality, in large part related to high rates of hospitalizations. The clinical manifestations of heart failure are similar regardless of the ejection fraction. Unlike heart failure with reduced ejection fraction, there are few therapeutic options for treating heart failure with preserved ejection fraction. Molecular therapies that have shown reduced mortality and morbidity in heart failure with reduced ejection have not been proven to be effective for patients with heart failure and preserved ejection fraction. The study of pathophysiological processes involved in the production of heart failure with preserved ejection fraction is the basis for identifying new therapeutic means. In this narrative review, we intend to synthesize the existing therapeutic means, but also those under research (metabolic and microRNA therapy) for the treatment of heart failure with preserved ejection fraction.

Association Between Epicardial Adipose Tissue and Left Atrial and Ventricular Function in Patients With Heart Failure: A Systematic Review and Meta-Analysis

Existing evidence suggested that the role of epicardial adipose tissue (EAT) in heart failure with reduced and preserved ejection fraction (HFrEF/HFpEF) might be divergent. Here, we conducted a systematic review and meta-analysis to evaluate the association between EAT and HF. Several databases were searched from their inception to January 20, 2023. We calculated the standard mean difference (SMD) in EAT between the HF and control groups, as well as the correlation coefficient between EAT and left atrial (LA) and left ventricular (LV) function. This meta-analysis included 23 studies, involving 1563 HFrEF and 1351 HFpEF patients. Our findings indicated that EAT was significantly higher in HFpEF patients (SMD: 0.61, 95% CI: 0.27-0.94), but not in total HF or HFrEF patients compared to controls. In HFrEF, EAT was positively correlated with LVEF, LV end-diastolic volume index (LVEDVI), LA global longitudinal strain (LAGLS), and negatively correlated with N-terminal pro-B-type natriuretic peptide (NT-ProBNP). However, no significant relationship existed between EAT and LV mass index (LVMI) or LVGLS. For HFpEF, EAT correlated positively with LVMI, LVEDVI, LV end-systolic volume index (LVESVI), LA volume index (LAVI), cardiac troponin T, and extracellular volume (ECV), but negatively with LVGLS and LAGLS. EAT was shown to be higher in HFpEF, but not in HFrEF. Less EAT was linked with worse LA function but not worse LV function in HFrEF, while more EAT was associated with worse LA/LV function in HFpEF.

Uncovering the Role of Epicardial Adipose Tissue in Heart Failure With Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is the most common form of heart failure. Obesity is a modifiable risk factor of HFpEF; however, body mass index provides limited information on visceral adiposity and patients with similar anthropometrics can present variable cardiovascular risk. Epicardial adipose tissue (EAT) is the closest fat deposit to the heart and has been proposed as a biomarker of visceral adiposity. EAT may be particularly important for cardiac function, because of its location (under the pericardium) and because it acts as a metabolically active endocrine organ (which can produce both beneficial and detrimental cytokines). In this paper, the authors review the role of EAT in normal and pathologic conditions and discuss the noninvasive imaging modalities that allow its identification. This review highlights EAT implications in HFpEF and discuss new therapies that act on EAT and might also exert beneficial effects on the cardiovascular system.

Epicardial Adipose Tissue in Myocardial Disease: From Physiology to Heart Failure Phenotypes

Epicardial adipose tissue (EAT) is increasingly being recognized as a determinant of myocardial biology. The EAT-heart crosstalk suggests causal links between dysfunctional EAT and cardiomyocyte impairment. Obesity promotes EAT dysfunction and shifts in secreted adipokines which adversely affect cardiac metabolism, induce cardiomyocyte inflammation, redox imbalance and myocardial fibrosis. Thus, EAT determines cardiac phenotype via effects on cardiac energetics, contractility, diastolic function, and atrial conduction. Vice-versa the EAT is altered in heart failure (HF), and such phenotypic changes can be detected by noninvasive imaging or incorporated in Artificial Intelligence-enhanced tools to aid the diagnosis, subtyping or risk prognostication of HF. In the present article, we summarize the links between EAT and the heart, explaining how the study of epicardial adiposity can improve the understanding of cardiac disease, serve as a source of diagnostic and prognostic biomarkers, and as a potential therapeutic target in HF to improve clinical outcomes.

Epicardial Adipose Tissue and Development of Atrial Fibrillation (AFIB) and Heart Failure With Preserved Ejection Fraction (HFpEF)

Epicardial adipose tissue (EAT) has been associated with the development of many cardiovascular abnormalities, of which the development of atrial fibrillation (AFIB) in this group of patients is not an uncommon finding. Several mechanisms have been proposed to explain the role of EAT in the development of AFIB. It involves cardiac remodeling owing to the underlying fatty infiltration and the subsequent inflammation and fibrosis. This leads to the formation of ectopic foci that can lead to AFIB. Some studies propose that structural and valvular heart disease and increased hemodynamic stress further augment the development of AFIB in patients with underlying EAT. The degree of development of AFIB is also related to EAT thickness and volume. Therefore, EAT quantification can be used as an imaging technique to predict cardiovascular outcomes in these patients. Obesity also plays an important role in the development of AFIB both as an independent factor and by leading to adipose tissue deposition on the epicardial tissue. Understanding the pathophysiology of EAT is important as it can lead to the development of therapies that can target obesity as a risk factor for preventing AFIB. Some promising therapies have already been investigated for decreasing the risk of AFIB in patients with EAT. Dietary changes and weight loss have been shown to reduce the deposition of fat on epicardial tissue. Antidiabetic drugs and statin therapy have also shown promising results. Bariatric surgery has been shown to decrease EAT volume on echocardiography in obese patients.

Association between the triglyceride-glucose index and the risk of mortality among patients with chronic heart failure: results from a retrospective cohort study in China

BACKGROUND

The triglyceride-glucose (TyG) index has been demonstrated to be a reliable surrogate marker of insulin resistance (IR) and an effective predictive index of cardiovascular (CV) disease risk. However, its long-term prognostic value in patients with chronic heart failure (CHF) remains uncertain.

METHODS

A total of 6697 consecutive patients with CHF were enrolled in this study. Patients were divided into tertiles according to their TyG index. The incidence of primary outcomes, including all-cause death and CV death, was recorded. The TyG index was calculated as ln [fasting triglycerides (mg/dL) × fasting blood glucose (mg/dL)/2].

RESULTS

During a median follow-up of 3.9 years, a total of 2158 (32.2%) all-cause deaths and 1305 (19.5%) CV deaths were documented. The incidence of primary events from the lowest to the highest TyG index tertiles were 50.61, 64.64, and 92.25 per 1000 person-years for all-cause death and 29.05, 39.40, and 57.21 per 1000 person-years for CV death. The multivariate Cox hazards regression analysis revealed hazard ratios for all-cause and CV deaths of 1.84 (95% CI 1.61-2.10; P for trend < 0.001) and 1.94 (95% CI 1.63-2.30; P for trend < 0.001) when the highest and lowest TyG index tertiles were compared. In addition, the predictive ability of the TyG index against all-cause death was more prominent among patients with metabolic syndrome and those with heart failure with preserved ejection fraction phenotype (both P for interaction < 0.05). Furthermore, adding the TyG index to the established model for all-cause death improved the C‑statistic value (0.710 for the established model vs. 0.723 for the established model + TyG index, P < 0.01), the integrated discrimination improvement value (0.011, P < 0.01), the net reclassification improvement value (0.273, P < 0.01), and the clinical net benefit (probability range, 0.07-0.36).

CONCLUSIONS

The TyG index was significantly associated with the risk of mortality, suggesting that it may be a reliable and valuable predictor for risk stratification and an effective prognostic indicator in patients with CHF.

SGLT2i alleviates epicardial adipose tissue inflammation by modulating ketone body-glyceraldehyde-3-phosphate dehydrogenase malonylation pathway

AIMS

Inflammation in the epicardial adipose tissue (EAT) is a contributor to atrial fibrillation. Studies have reported that sodium glucose co-transporter 2 inhibitor (SGLT2i) can alleviate EAT inflammation. However, the mechanism remains elusive. This study aims to investigate the molecular mechanism of SGLT2i in reducing EAT inflammation and to explore the effects of SGLT2i on atrial fibrosis in atrial fibrillation.

METHODS

Sprague-Dawley rats were injected with angiotensin II to induce atrial fibrillation and randomly assigned to receive SGLT2i ( n  = 6) or vehicle ( n  = 6). Macrophages (RAW264.7) were treated with ketone bodies; ACC1 knockdown/overexpression and malonyl-CoA overexpression were performed in vitro . The levels of inflammatory cytokines, ACC1, and malonyl-CoA were examined by ELISA. GAPDH malonylation was measured by co-immunoprecipitation.

RESULTS

In atrial fibrillation rats, SGLT2i increased the ketone body levels and decreased the expression of ACC1 and alleviated EAT inflammation and atrial fibrosis. In RAW264.7 cells, ketone bodies decreased the levels of ACC1, malonyl-CoA, and GAPDH malonylation, accompanied by reduced inflammatory cytokines. ACC1 knockdown decreased the expression of malonyl-CoA and GAPDH malonylation and alleviated lipopolysaccharide (LPS)-induced macrophage inflammation; these effects were inhibited by malonyl-CoA overexpression. Furthermore, the protective effects of ketone bodies on macrophage inflammation were abrogated by ACC1 overexpression.

CONCLUSION

SGLT2i alleviates EAT inflammation by reducing GAPDH malonylation via downregulating the expression of ACC1 through increasing ketone bodies, thus attenuating atrial fibrosis.

Ischemia with Nonobstructive Coronary Artery Disease and Atrial Cardiomyopathy-Two Sides of the Same Story?

Ischemia with nonobstructive coronary artery disease (INOCA) is increasingly recognized as a significant cause of angina, myocardial remodeling, and eventually heart failure (HF). Coronary microvascular dysfunction (CMD) is a major endotype of INOCA, and it is caused by structural and functional alterations of the coronary microcirculation. At the same time, atrial cardiomyopathy (ACM) defined by structural, functional, and electrical atrial remodeling has a major clinical impact due to its manifestations: atrial fibrillation (AF), atrial thrombosis, stroke, and HF symptoms. Both these pathologies share similar risk factors and have a high comorbidity burden. CMD causing INOCA and ACM frequently coexist. Thus, questions arise whether there is a potential link between these pathologies. Does CMD promote AF or the reverse? Which are the mechanisms that ultimately lead to CMD and ACM? Are both part of a systemic disease characterized by endothelial dysfunction? Lastly, which are the therapeutic strategies that can target endothelial dysfunction and improve the prognosis of patients with CMD and ACM? This review aims to address these questions by analyzing the existing body of evidence, offering further insight into the mechanisms of CMD and ACM, and discussing potential therapeutic strategies.

Inflammatory pathways in heart failure with preserved left ventricular ejection fraction: implications for future interventions

Many patients with symptoms and signs of heart failure have a left ventricular ejection fraction ≥50%, termed heart failure with preserved ejection fraction (HFpEF). HFpEF is a heterogeneous syndrome mainly affecting older people who have many other cardiac and non-cardiac conditions that often cast doubt on the origin of symptoms, such as breathlessness, or signs, such as peripheral oedema, rendering them neither sensitive nor specific to the diagnosis of HFpEF. Currently, management of HFpEF is mainly directed at controlling symptoms and treating comorbid conditions such as hypertension, atrial fibrillation, anaemia, and coronary artery disease. HFpEF is also characterized by a persistent increase in inflammatory biomarkers. Inflammation may be a key driver of the development and progression of HFpEF and many of its associated comorbidities. Detailed characterization of specific inflammatory pathways may provide insights into the pathophysiology of HFpEF and guide its future management. There is growing interest in novel therapies specifically designed to target deregulated inflammation in many therapeutic areas, including cardiovascular disease. However, large-scale clinical trials investigating the effectiveness of anti-inflammatory treatments in HFpEF are still lacking. In this manuscript, we review the role of inflammation in HFpEF and the possible implications for future trials.

Systematic review and meta-analysis of the association between all-cause mortality and statin therapy in patients with preserved ejection fraction heart failure (HFpEF)

BACKGROUND

Heart failure (HF) is a growing global health burden increasing in prevalence as the average age of the population rises. HF with preserved ejection fraction (HFpEF) is defined as EF that is ≥50% and represents almost half of the population with HF.

METHODS

We conducted a systematic review and meta-analysis exploring an association between HFpEF and statin use on all-cause mortality and cardiovascular rehospitalisation. Searches were conducted in MEDLINE via Ovid, The Cochrane Library for clinical trials in CENTRAL and Embase via Ovid for articles published between 1 January 2000 and 2 July 2021. Risk of bias was assessed using the Newcastle-Ottawa Scale and evidence rated for quality using the GRADE approach.

RESULTS

A total of 19 studies were included in the review. The analysis suggests a risk reduction of 27% for the statin exposed participants compared to the statin non-exposed participants (HR 0.73, 95% CI: 0.68-0.79) with regard to all-cause mortality. There is a low level of heterogeneity (I² = 38%) associated with this result that has been accounted for by using a random effects model, however given the included studies are observational, the quality of the evidence is rated as low. Information on rehospitalisation was insufficient for determining the impact of statin use on rehospitalisations.

CONCLUSION

Our meta-analysis revealed a reduction in all-cause mortality in patients with HFpEF on statin therapy. Considering the outcomes from this meta-analysis there is a need for high level studies to provide quality evidence on the use of statins in patients with HFpEF.

Epicardial adipocytes in the pathogenesis of atrial fibrillation: An update on basic and translational studies

Epicardial adipose tissue (EAT) is an endocrine organ containing a host of cell types and undoubtedly serving a multitude of important physiologic functions. Aging and obesity cause hypertrophy of EAT. There is great interest in the possible connection between EAT and cardiovascular disease, in particular, atrial fibrillation (AF). Increased EAT is independently associated with AF and adverse events after AF ablation (e.g., recurrence of AF, and stroke). In general, the amount of EAT correlates with BMI or visceral adiposity. Yet on a molecular level, there are similarities and differences between epicardial and abdominal visceral adipocytes. In comparison to subcutaneous adipose tissue, both depots are enriched in inflammatory cells and chemokines, even in normal conditions. On the other hand, in comparison to visceral fat, epicardial adipocytes have an increased rate of fatty acid release, decreased size, and increased vascularity. Several studies have described an association between fibrosis of EAT and fibrosis of the underlying atrial myocardium. Others have discovered paracrine factors released from EAT that could possibly mediate this association. In addition to the adjacent atrial cardiomyocytes, EAT contains a robust stromal-vascular fraction and surrounds the ganglionic plexi of the cardiac autonomic nervous system (cANS). The importance of the cANS in the pathogenesis of atrial fibrillation is well known, and it is quite likely that there is feedback between EAT and the cANS. This complex interplay may be crucial to the maintenance of normal sinus rhythm or the development of atrial fibrillation. The extent the adipocyte is a microcosm of metabolic health in the individual patient may determine which is the predominant rhythm.

Epicardial fat and atrial fibrillation: the perils of atrial failure

Obesity is a heterogeneous condition, characterized by different phenotypes and for which the classical assessment with body mass index may underestimate the real impact on cardiovascular (CV) disease burden. An epidemiological link between obesity and atrial fibrillation (AF) has been clearly demonstrated and becomes even more tight when ectopic (i.e. epicardial) fat deposition is considered. Due to anatomical and functional features, a tight paracrine cross-talk exists between epicardial adipose tissue (EAT) and myocardium, including the left atrium (LA). Alongside-and even without-mechanical atrial stretch, the dysfunctional EAT may determine a pro-inflammatory environment in the surrounding myocardial tissue. This evidence has provided a new intriguing pathophysiological link with AF, which in turn is no longer considered a single entity but rather the final stage of atrial remodelling. This maladaptive process would indeed include structural, electric, and autonomic derangement that ultimately leads to overt disease. Here, we update how dysfunctional EAT would orchestrate LA remodelling. Maladaptive changes sustained by dysfunctional EAT are driven by a pro-inflammatory and pro-fibrotic secretome that alters the sinoatrial microenvironment. Structural (e.g. fibro-fatty infiltration) and cellular (e.g. mitochondrial uncoupling, sarcoplasmic reticulum fragmentation, and cellular protein quantity/localization) changes then determine an electrophysiological remodelling that also involves the autonomic nervous system. Finally, we summarize how EAT dysfunction may fit with the standard guidelines for AF. Lastly, we focus on the potential benefit of weight loss and different classes of CV drugs on EAT dysfunction, LA remodelling, and ultimately AF onset and recurrence.

Proteomic analysis of epicardial adipose tissue from heart disease patients with concomitant heart failure with preserved ejection fraction

BACKGROUND

Although epicardial adipose tissue (EAT) is known to be a major contributor to the pathogenesis of heart failure with preserved ejection fraction (HFpEF), the underlying mechanisms remain incompletely understood. This study aimed to compare the proteomic profiles of EAT from HFpEF patients and patients without HF (non-HF) and to explore candidate molecules characteristic of EAT in HFpEF.

METHODS

EAT samples were collected from patients who underwent cardiac surgery. Proteins were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Gene Ontology (GO) enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, and protein-protein interaction network analysis were conducted. The gene expression of one significant differentially expressed protein was examined by quantitative reverse transcription polymerase chain reaction.

RESULTS

A total of 2416 proteins were detected by LC-MS/MS experiments, and expression levels were quantified for 2349 proteins. Among them, 96 proteins (including 71 upregulated proteins and 25 downregulated proteins) were significantly differentially expressed between the HFpEF (n = 5) and non-HF groups (n = 5). GO enrichment and KEGG pathway analyses revealed that these differentially expressed proteins were predominantly involved in HFpEF-related processes, including lipid metabolic disorder, inflammation, and mitochondrial dysfunction.

CONCLUSIONS

The results of this comprehensive analysis of the EAT proteome in HFpEF patients offer new insights into the pathogenesis of HFpEF and potential molecular targets in EAT.

Association between epicardial adipose tissue and recurrence of atrial fibrillation after ablation: a propensity score-matched analysis

To assess the association between epicardial adipose tissue (EAT) index derived from cardiac computed tomography and atrial fibrillation (AF) recurrence after ablation by comparing with a propensity score matched non-recurrence AF patients. A total of 506 patients with AF recurrence and 174 patients without AF recurrence were enrolled in this retrospective study. Density and volume of total EAT surrounding the heart (Total-EAT) and EAT surrounding the left atrium (LA-EAT) were measured, propensity score matching(PSM) analyses were used to compare the outcomes of the two groups while controlling for confounders. Total-EAT density (HU) value (-81.27 ± 4.67 vs -84.05 ± 3.84, P < 0.001) and LA-EAT density (HU) value (-76.16 ± 4.11 vs -78.83 ± 3.81, P < 0.001) were significantly higher in the patients with AF recurrence than in those without recurrence. LA-EAT density (HU) value was significantly higher than Total-EAT (- 77.50 ± 4.18 vs -82.66 ± 4.49, P = 0.000). In a multiple logistic regression analysis, a higher LA-EAT density (odds ratio: 1.12; 95% CI: 1.02-1.22, p = 0.015) was significantly associated with the AF recurrence after adjusting for other risk factors. The LA-EAT density plays an important role in the AF recurrence after ablation. Assessment of LA-EAT density can improve ablation outcomes by refining patient selection.

Future scope and challenges for congestive heart failure: Moving towards development of pharmacotherapy

Heart failure is invariably associated with cardiac hypertrophy and impaired cardiac performance. Although several drugs have been developed to delay the progression of heart failure, none of the existing interventions have shown beneficial effects in reducing morbidity and mortality. In order to determine specific targets for future drug development, we have discussed different mechanisms involving both cardiomyocytes and non-myocyte (extracellular matrix) alterations for the transition of cardiac hypertrophy to heart failure as well as for the progression of heart failure. We have emphasized the role of oxidative stress, inflammatory cytokines, metabolic alterations and Ca2+-handling defects in adverse cardiac remodeling and heart dysfunction in hypertrophied myocardium. Alterations in the regulatory process due to several protein kinases as well as participation of mitochondrial Ca2+-overload, activation of proteases and phospholipases and changes in gene expression for subcellular remodeling have also been described for the occurrence of cardiac dysfunction. Association of cardiac arrhythmia with heart failure has been explained as a consequence of catecholamine oxidation products. Since these multifactorial defects in extracellular matrix and cardiomyocytes are evident in the failing heart, it is a challenge for experimental cardiologists to develop appropriate combination drug therapy for improving cardiac function in heart failure.

Sex Differences in Epicardial Adipose Tissue: Association With Atrial Fibrillation Ablation Outcomes

Background

There are significant differences in the prevalence and prognosis of atrial fibrillation (AF) between sexes. Epicardial adipose tissue (EAT) has been found as a risk factor for AF. This study aimed to evaluate whether sex-based EAT differences were correlated with AF recurrence and major adverse cardiovascular events (MACE).

Methods

In this study, postmenopausal women and age, BMI, and type of AF matched men who had received first catheter ablation were included. EAT volume was quantified based on the pre-ablation cardiac computed tomography (CT) images. Clinical, CT, and echocardiographic variables were compared by sex groups. The predictors of AF recurrence and MACE were determined through Cox proportional hazards regression.

Results

Women were found with significantly lower total EAT volumes (P < 0.001) but higher periatrial/total (P/T) EAT ratios (P = 0.009). The median follow-up duration was 444.5 days. As revealed by the result of the Kaplan-Meier survival analysis, the women were found to have a significantly higher prevalence of AF recurrence (log rank, P = 0.011) but comparable MACE (log rank, P = 0.507) than men. Multivariate analysis demonstrated that female gender (HR: 1.88 [95% CI: 1.03, 4.15], P = 0.032), persistent AF (HR: 2.46 [95% CI: 1.19, 5.05], P = 0.015), left atrial (LA) dimension (HR: 1.47 [95% CI: 1.02, 2.13], P = 0.041), and P/T EAT ratio (HR: 1.73 [95% CI: 1.12, 2.67], P = 0.013) were found as the independent predictors of AF recurrence. Sex-based subgroup multivariable analysis showed that the P/T EAT ratio was an independent predictor of AF recurrence in both men (HR: 1.13 [95% CI: 1.01, 1.46], P = 0.047) and women (HR: 1.37 [95% CI: 1.11, 1.67], P = 0.028). While age (HR: 1.81 [95% CI: 1.18, 2.77], P = 0.007), BMI (HR: 1.44 [95% CI: 1.02, 2.03], P = 0.038), and periatrial EAT volume (HR: 1.31 [95% CI: 1.01, 1.91], P = 0.046) were found to be independent of MACE.

Conclusion

Women had a higher P/T EAT ratio and AF post-ablation recurrence but similar MACE as compared with men. Female gender and P/T EAT ratio were found to be independent predictors of AF recurrence, whereas age and periatrial EAT volume were found to be independent predictors of MACE.

Epicardial Adipose Tissue related to Left Atrial and Ventricular Function in Heart Failure with Preserved (HFpEF) versus Reduced and Mildly Reduced Ejection Fraction (HFrEF/HFmrEF)

BACKGROUND

Different associations between epicardial adipose tissue (EAT) and cardiac function have been suggested in patients with heart failure with preserved (HFpEF) versus reduced and mildly reduced ejection fraction (HFrEF/HFmrEF). However, few studies have directly compared the association between EAT and left atrial (LA) and ventricular (LV) function in patients with HFpEF and HFrEF/HFmrEF.

METHODS

We studied EAT thickness using transthoracic echocardiography in a multicenter cohort of 149 community-dwelling controls without HF, 99 patients with HFpEF, and 366 patients with HFrEF/HFmrEF. EAT thickness was averaged from parasternal long-axis and short-axis views, respectively, and off-line speckle tracking analysis was performed to quantify LA and LV function. Data were validated in an independent cohort of 626 controls, 243 patients with HFpEF, and 180 patients with HFrEF/HFmrEF. For LV function, LV global longitudinal strain (GLS) was measured in both derivation and validation cohorts. For the LA function, LAGLS at reservoir, contractile and conduit phase were measured in the derivation cohort, and only LAGLS at reservoir phase was measured in the validation cohort.

RESULTS

In the derivation cohort, EAT thickness was lower in HFrEF/HFmrEF (7.3±2.5mm) compared to HFpEF (8.3±2.6mm, p<0.05) and controls (7.9±1.8mm, p<0.05). Greater EAT thickness was associated with better LV and contractile LA function in HFrEF/HFmrEF, but not in HFpEF (p for interaction < 0.05). These findings were confirmed in the validation cohort, where EAT thickness was lower in HFrEF/HFmrEF (6.7±1.4mm) compared to HFpEF (9.6±2.8mm; p<0.05) and controls (7.7±2.3mm; p<0.05). Greater EAT thickness was associated with better LV and reservoir LA function in patients with HFrEF/HFmrEF but worse LV and reservoir LA function in patients with HFpEF (p for interaction <0.05). Thickened EAT (EAT thickness >10mm) was associated with LA dysfunction (LAGLS at reservoir phase<23%) in HFpEF, but not in HFrEF/HFmrEF.

CONCLUSION

EAT thickness is greater in patient with HFpEF than HFrEF/HFmrEF. Increased EAT thickness is associated with worse LA and LV function in HFpEF but the opposite in HFrEF/HFmrEF. This article is protected by copyright. All rights reserved.

Pathophysiological aspects of insulin resistance in Atrial Fibrillation: novel therapeutic approaches

Background

Insulin resistance is associated with metabolic disorders including diabetes, obesity, hypertension, and inflammation which are the risk factors for Atrial Fibrillation. Many studies have reported that type 2 diabetes and AF are related and also their prevalence is increasing globally. Moreover, insulin resistance begins the type 2 diabetes.

Main body

This review explains the pathophysiological aspects of insulin resistance in AF patients and discusses the drugs that are used to manage insulin resistance including Biguanides (metformin), thiazolidinediones (TZDs) [Pioglitazone, rosiglitazone], Sodium-glucose cotransporter 2 (SGLT2) inhibitors, Concentrated Insulin Products, Dipeptidyl peptidase-4 (DPP-4) Inhibitors, Glucagon-like peptide 1 (GLP-1) receptor Agonists, Pramlintide, Sulfonylureas, Meglitinides, α-Glucosidase Inhibitors, Colesevelam, Bromocriptine. This review will highlight a few major drugs that played a significant role in AF patients. For this purpose, many databases were used for reviewing the literature and keywords are used such as Insulin Resistance, Pathophysiology, Atrial Fibrillation, and Drugs.

Conclusion

This review article concludes that insulin resistance is related to AF. It also provides an outlook on the recent pathophysiological aspects of insulin resistance in AF; however, more studies are needed to clarify the management of insulin resistance in AF patients to prevent the development of type 2 diabetes.

Mechanisms Underlying Antiarrhythmic Properties of Cardioprotective Agents Impacting Inflammation and Oxidative Stress

The prevention of cardiac life-threatening ventricular fibrillation and stroke-provoking atrial fibrillation remains a serious global clinical issue, with ongoing need for novel approaches. Numerous experimental and clinical studies suggest that oxidative stress and inflammation are deleterious to cardiovascular health, and can increase heart susceptibility to arrhythmias. It is quite interesting, however, that various cardio-protective compounds with antiarrhythmic properties are potent anti-oxidative and anti-inflammatory agents. These most likely target the pro-arrhythmia primary mechanisms. This review and literature-based analysis presents a realistic view of antiarrhythmic efficacy and the molecular mechanisms of current pharmaceuticals in clinical use. These include the sodium-glucose cotransporter-2 inhibitors used in diabetes treatment, statins in dyslipidemia and naturally protective omega-3 fatty acids. This approach supports the hypothesis that prevention or attenuation of oxidative and inflammatory stress can abolish pro-arrhythmic factors and the development of an arrhythmia substrate. This could prove a powerful tool of reducing cardiac arrhythmia burden.

Left atrial structure and function in heart failure with reduced (HFrEF) versus preserved ejection fraction (HFpEF): systematic review and meta-analysis

Left atrial (LA) structure and function in heart failure with reduced (HFrEF) versus preserved ejection fraction (HFpEF) is only established in small studies. Therefore, we conducted a systematic review of LA structure and function in order to find differences between patients with HFrEF and HFpEF. English literature on LA structure and function using echocardiography was reviewed to calculate pooled prevalence and weighted mean differences (WMD). A total of 61 studies, comprising 8806 patients with HFrEF and 9928 patients with HFpEF, were included. The pooled prevalence of atrial fibrillation (AF) was 34.4% versus 42.8% in the acute inpatient setting, and 20.1% versus 33.1% in the chronic outpatient setting when comparing between HFrEF and HFpEF. LA volume index (LAVi), LA reservoir global longitudinal strain (LAGLS_R), and E/e’ was 59.7 versus 52.7 ml/m², 9.0% versus 18.9%, and 18.5 versus 14.0 in the acute inpatient setting, and 48.3 versus 38.2 ml/m², 12.8% versus 23.4%, and 16.9 versus 13.5 in the chronic outpatient setting when comparing HFrEF versus HFpEF, respectively. The relationship between LAVi and LAGLS_R was significant in HFpEF, but not in HFrEF. Also, in those studies that directly compared patients with HFrEF versus HFpEF, those with HFrEF had worse LAGLS_R [WMD = 16.3% (22.05,8.61); p < 0.001], and higher E/e’ [WMD = −0.40 (−0.56, −0.24); p < 0.05], while LAVi was comparable. When focusing on acute hospitalized patients, E/e’ was comparable between patients with HFrEF and HFpEF. Despite the higher burden of AF in HFpEF, patients with HFrEF had worse LA global function. Left atrial myopathy is not specifically related to HFpEF.

Effects of Metformin in Heart Failure: From Pathophysiological Rationale to Clinical Evidence

Type 2 diabetes mellitus (T2DM) is a worldwide major health burden and heart failure (HF) is the most common cardiovascular (CV) complication in affected patients. Therefore, identifying the best pharmacological approach for glycemic control, which is also useful to prevent and ameliorate the prognosis of HF, represents a crucial issue. Currently, the choice is between the new drugs sodium/glucose co-transporter 2 inhibitors that have consistently shown in large CV outcome trials (CVOTs) to reduce the risk of HF-related outcomes in T2DM, and metformin, an old medicament that might end up relegated to the background while exerting interesting protective effects on multiple organs among which include heart failure. When compared with other antihyperglycemic medications, metformin has been demonstrated to be safe and to lower morbidity and mortality for HF, even if these results are difficult to interpret as they emerged mainly from observational studies. Meta-analyses of randomized controlled clinical trials have not produced positive results on the risk or clinical course of HF and sadly, large CV outcome trials are lacking. The point of force of metformin with respect to new diabetic drugs is the amount of data from experimental investigations that, for more than twenty years, still continues to provide mechanistic explanations of the several favorable actions in heart failure such as, the improvement of the myocardial energy metabolic status by modulation of glucose and lipid metabolism, the attenuation of oxidative stress and inflammation, and the inhibition of myocardial cell apoptosis, leading to reduced cardiac remodeling and preserved left ventricular function. In the hope that specific large-scale trials will be carried out to definitively establish the metformin benefit in terms of HF failure outcomes, we reviewed the literature in this field, summarizing the available evidence from experimental and clinical studies reporting on effects in heart metabolism, function, and structure, and the prominent pathophysiological mechanisms involved.

Regional Adiposity and Risk of Heart Failure and Mortality: The Jackson Heart Study

Background Visceral adipose tissue (VAT) is associated with incident heart failure (HF) and HF with preserved ejection fraction, yet it is unknown how pericardial and abdominal adiposity affect HF and mortality risks in Black individuals. We examined the associations of pericardial adipose tissue (PAT), VAT, and subcutaneous adipose tissue (SAT) with incident HF hospitalization and all-cause mortality in a large community cohort of Black participants. Methods and Results Among the 2882 Jackson Heart Study Exam 2 participants without prevalent HF who underwent body computed tomography, we used Cox proportional hazards models to examine associations between computed tomography-derived regional adiposity and incident HF hospitalization and all-cause mortality. Fully adjusted models included demographics and cardiovascular disease risk factors. Median follow-up was 10.6 years among participants with available VAT (n=2844), SAT (n=2843), and PAT (n=1386). Fully adjusted hazard ratios (95% CIs) of distinct computed tomography-derived adiposity measures (PAT per 10 cm3, VAT or SAT per 100 cm3) were as follows: for incident HF, PAT 1.08 (95% CI, 1.02-1.14) and VAT 1.04 (95% CI, 1.01-1.08); for HF with preserved ejection fraction, PAT 1.13 (95% CI, 1.04-1.21) and VAT 1.07 (95% CI, 1.01-1.13); for mortality, PAT 1.07 (95% CI, 1.03-1.12) and VAT 1.01 (95% CI, 0.98-1.04). SAT was not associated with either outcome. Conclusions High PAT and VAT, but not SAT, were associated with incident HF and HF with preserved ejection fraction, and only PAT was associated with mortality in the fully adjusted models in a longitudinal community cohort of Black participants. Future studies may help understand whether changes in regional adiposity improves HF, particularly HF with preserved ejection fraction, risk predictions. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT00005485.

Importance of epicardial adipose tissue localization using cardiac magnetic resonance imaging in patients with heart failure with mid-range and preserved ejection fraction

BACKGROUND

Epicardial adipose tissue (EAT) has been implicated in the pathophysiology of heart failure (HF) with left ventricular ejection fraction (LVEF) >40%, but whether this is due to a regional or global effect of EAT remains unclear.

HYPOTHESIS

Regional EAT is associated with alterations in local cardiac structure and function.

METHODS

Patients with HF and LVEF >40% were studied. Cardiac Magnetic Resonance imaging was used to localize EAT surrounding the right ventricle (RV) and LV separately, using anterior- and posterior interventricular grooves as boundaries. Atrial- and ventricular EAT were differentiated using the mitral-valve position. All EAT depots were related to the adjacent myocardial structure.

RESULTS

102 consecutive HF patients were enrolled. The majority of EAT was present around the RV (42% of total EAT, p < .001). RV-EAT showed a strong association with increased RV mass (β = 0.60, p < .001) and remained associated with RV mass after adjusting for total EAT, sex, N-terminal prohormone of brain natriuretic peptide (NT-proBNP), renal function and blood glucose. LV-EAT showed a similar association with LV mass in univariable analysis, albeit less pronounced (β = 0.24, p = .02). Atrial EAT was increased in patients with atrial fibrillation compared to those without atrial fibrillation (30 vs. 26 ml/m² , p = .04), whereas ventricular EAT was similar (74 vs. 75 ml/m² , p = .9).

CONCLUSIONS

Regional EAT is strongly associated with local cardiac structure and function in HF patients with LVEF >40%. These data support the hypothesis that regional EAT is involved in the pathophysiology of HF with LVEF >40%.

Left Atrial Myopathy in Atrial Fibrillation and Heart Failure: Clinical Implications, Mechanisms, and Therapeutic Targets

PURPOSE OF REVIEW

This review discusses the mechanisms, clinical implications, and treatments of left atrial (LA) myopathy in comorbid atrial fibrillation (AF) and heart failure (HF) across the spectrum of ejection fraction.

RECENT FINDINGS

AF and HF are highly comorbid conditions. Left atrial (LA) myopathy, characterized by impairments in LA structure, function, or electrical conduction, plays a fundamental role in the development of both AF and HF with preserved ejection fraction (AF-HFpEF) along with AF and HF with reduced ejection fraction (AF-HFrEF). While the nature of LA myopathy in AF-HFpEF is unique from that of AF-HFrEF, LA myopathy also leads to progression of both of these conditions. There may be a vulnerable cohort of AF-HF patients who have a disproportionate degree of LA myopathy compared with left ventricular (LV) dysfunction. Further investigations are required to identify therapies to improve LA function in this cohort.

Can We Decrease Epicardial and Pericardial Fat in Patients With Diabetes?

Diabetes mellitus (DM) is a chronic and complex metabolic disorder and also an important cause of cardiovascular (CV) disease (CVD). Patients with type 2 DM (T2DM) and obesity show a greater propensity for visceral fat deposition (and excessive fat deposits elsewhere) and the link between adiposity and CVD risk is greater for visceral than for subcutaneous (SC) adipose tissue (AT). There is growing evidence that epicardial AT (EAT) and pericardial AT (PAT) play a role in the development of DM-related atherosclerosis, atrial fibrillation (AF), myocardial dysfunction, and heart failure (HF). In this review, we will highlight the importance of PAT and EAT in patients with DM. We also consider therapeutic interventions that could have a beneficial effect in terms of reducing the amount of AT and thus CV risk. EAT is biologically active and a likely determinant of CV morbidity and mortality in patients with DM, given its anatomical characteristics and proinflammatory secretory pattern. Consequently, modification of EAT/PAT may become a therapeutic target to reduce the CV burden. In patients with DM, a low calorie diet, exercise, antidiabetics and statins may change the quantity of EAT, PAT or both, alter the secretory pattern of EAT, improve the metabolic profile, and reduce inflammation. However, well-designed studies are needed to clearly define CV benefits and a therapeutic approach to EAT/PAT in patients with DM.

Metformin Use Is Associated With a Lower Incidence of Hospitalization for Atrial Fibrillation in Patients With Type 2 Diabetes Mellitus

Background: The effect of metformin on the risk of atrial fibrillation (AF) requires confirmation. This retrospective cohort study compared the incidence of hospitalization for AF in ever and never users of metformin.

Methods: Patients with newly diagnosed type 2 diabetes mellitus during 1999–2005 were enrolled from Taiwan's National Health Insurance database. Analyses were conducted in both an unmatched cohort of 173,398 ever users and 21,666 never users and in a propensity score-matched cohort of 21,662 pairs of ever and never users. They were free from a diagnosis of AF before January 1, 2006 and were followed up until December 31, 2011. Hazard ratios were estimated by Cox regression incorporated with the inverse probability of treatment weighting using the propensity score.

Results: A total of 303 ever users and 86 never users in the unmatched cohort and 56 ever users and 86 never users in the matched cohort developed hospitalization for AF during follow-up. The respective incidence rates were 37.72 and 92.45 per 100,000 person-years in the unmatched cohort and were 56.98 and 92.46 per 100,000 person-years in the matched cohort. The hazard ratio for ever vs. never users was 0.405 (95% confidence interval: 0.319–0.515) in the unmatched cohort and 0.617 (0.441–0.864) in the matched cohort. Hazard ratios for the tertiles of cumulative duration of metformin therapy vs. never users showed a dose-response effect. The findings were consistent in sensitivity analyses.

Conclusion: Metformin use is associated with a lower risk of hospitalization for AF in patients with type 2 diabetes mellitus.

Obesity, Hypertension, and Cardiac Dysfunction: Novel Roles of Immunometabolism in Macrophage Activation and Inflammation

Obesity and hypertension, which often coexist, are major risk factors for heart failure and are characterized by chronic, low-grade inflammation, which promotes adverse cardiac remodeling. While macrophages play a key role in cardiac remodeling, dysregulation of macrophage polarization between the proinflammatory M1 and anti-inflammatory M2 phenotypes promotes excessive inflammation and cardiac injury. Metabolic shifting between glycolysis and mitochondrial oxidative phosphorylation has been implicated in macrophage polarization. M1 macrophages primarily rely on glycolysis, whereas M2 macrophages rely on the tricarboxylic acid cycle and oxidative phosphorylation; thus, factors that affect macrophage metabolism may disrupt M1/M2 homeostasis and exacerbate inflammation. The mechanisms by which obesity and hypertension may synergistically induce macrophage metabolic dysfunction, particularly during cardiac remodeling, are not fully understood. We propose that obesity and hypertension induce M1 macrophage polarization via mechanisms that directly target macrophage metabolism, including changes in circulating glucose and fatty acid substrates, lipotoxicity, and tissue hypoxia. We discuss canonical and novel proinflammatory roles of macrophages during obesity-hypertension-induced cardiac injury, including diastolic dysfunction and impaired calcium handling. Finally, we discuss the current status of potential therapies to target macrophage metabolism during heart failure, including antidiabetic therapies, anti-inflammatory therapies, and novel immunometabolic agents.

Redefining Cardiovascular (CV) Death as a Primary Endpoint Component in Cardiovascular Outcome Trials

Sodium-Glucose cotransporter-2 inhibitors (SGLT-2i) and Glucagon-like peptide 1 receptor agonists (GLP1-RA) have revolutionised the approach for modern management of type 2 diabetes in view of their outcome altering abilities. An objective component of the primary endpoints used in the Cardiovascular Outcome Trials (CVOT) is cardiovascular (CV) death. However, the reason behind the decrease in CV deaths (compared to the placebo arm) appear to arise from divergent underlying processes. A recent meta-analysis of SGLT-2i and GLP1-RA indicated that the reduction in CV death associated with the former is predominantly due to its impact on heart failure (HF), while the association with the latter is due to its effect on atherosclerotic cardiovascular disease (ASCVD). A Pearson's product- moment correlation coefficient (r) analysis was performed on SGLT-2i exposed to CVOTs, exploring the strength of the association between CV death and hospitalisation for HF (hHF) and myocardial infarction (MI). The strength of association was strongest with hHF and negative with MI. In view of these findings, it has been proposed that future CVOTs should use a more objective definition of CVD, defining well in advance the anticipated impact on CVD (either as a consequence of the reduction in HF or ASCVD).

Inflammaging as a common ground for the development and maintenance of sarcopenia, obesity, cardiomyopathy and dysbiosis

Sarcopenia, obesity and their coexistence, obese sarcopenia (OBSP) as well as atherosclerosis-related cardio-vascular diseases (ACVDs), including chronic heart failure (CHF), are among the greatest public health concerns in the ageing population. A clear age-dependent increased prevalence of sarcopenia and OBSP has been registered in CHF patients, suggesting mechanistic relationships. Development of OBSP could be mediated by a crosstalk between the visceral and subcutaneous adipose tissue (AT) and the skeletal muscle under conditions of low-grade local and systemic inflammation, inflammaging. The present review summarizes the emerging data supporting the idea that inflammaging may serve as a mutual mechanism governing the development of sarcopenia, OBSP and ACVDs. In support of this hypothesis, various immune cells release pro-inflammatory mediators in the skeletal muscle and myocardium. Subsequently, the endothelial structure is disrupted, and cellular processes, such as mitochondrial activity, mitophagy, and autophagy are impaired. Inflamed myocytes lose their contractile properties, which is characteristic of sarcopenia and CHF. Inflammation may increase the risk of ACVD events in a hyperlipidemia-independent manner. Significant reduction of ACVD event rates, without the lowering of plasma lipids, following a specific targeting of key pro-inflammatory cytokines confirms a key role of inflammation in ACVD pathogenesis. Gut dysbiosis, an imbalanced gut microbial community, is known to be deeply involved in the pathogenesis of age-associated sarcopenia and ACVDs by inducing and supporting inflammaging. Dysbiosis induces the production of trimethylamine-N-oxide (TMAO), which is implicated in atherosclerosis, thrombosis, metabolic syndrome, hypertension and poor CHF prognosis. In OBSP, AT dysfunction and inflammation induce, in concert with dysbiosis, lipotoxicity and other pathophysiological processes, thus exacerbating sarcopenia and CHF. Administration of specialized, inflammation pro-resolving mediators has been shown to ameliorate the inflammatory manifestations. Considering all these findings, we hypothesize that sarcopenia, OBSP, CHF and dysbiosis are inflammaging-oriented disorders, whereby inflammaging is common and most probably the causative mechanism driving their pathogenesis.