Targeting Obesity and Diabetes to Treat Heart Failure with Preserved Ejection Fraction

Semaglutide versus placebo in people with obesity-related heart failure with preserved ejection fraction: a pooled analysis of the STEP-HFpEF and STEP-HFpEF DM randomised trials

BACKGROUND

In the STEP-HFpEF (NCT04788511) and STEP-HFpEF DM (NCT04916470) trials, the GLP-1 receptor agonist semaglutide improved symptoms, physical limitations, bodyweight, and exercise function in people with obesity-related heart failure with preserved ejection fraction. In this prespecified pooled analysis of the STEP-HFpEF and STEP-HFpEF DM trials, we aimed to provide a more definitive assessment of the effects of semaglutide across a range of outcomes and to test whether these effects were consistent across key patient subgroups.

METHODS

We conducted a prespecified pooled analysis of individual patient data from STEP-HFpEF and STEP-HFpEF DM, randomised, double-blind, placebo-controlled trials at 129 clinical research sites in 18 countries. In both trials, eligible participants were aged 18 years or older, had heart failure with a left ventricular ejection fraction of at least 45%, a BMI of at least 30 kg/m2, New York Heart Association class II-IV symptoms, and a Kansas City Cardiomyopathy Questionnaire Clinical Summary Score (KCCQ-CSS; a measure of heart failure-related symptoms and physical limitations) of less than 90 points. In STEP-HFpEF, people with diabetes or glycated haemoglobin A1c concentrations of at least 6·5% were excluded, whereas for inclusion in STEP-HFpEF DM participants had to have been diagnosed with type 2 diabetes at least 90 days before screening and to have an HbA1c of 10% or lower. In both trials, participants were randomly assigned to either 2·4 mg semaglutide once weekly or matched placebo for 52 weeks. The dual primary endpoints were change from baseline to week 52 in KCCQ-CSS and bodyweight in all randomly assigned participants. Confirmatory secondary endpoints included change from baseline to week 52 in 6-min walk distance, a hierarchical composite endpoint (all-cause death, heart failure events, and differences in changes in KCCQ-CSS and 6-min walk distance); and C-reactive protein (CRP) concentrations. Heterogeneity in treatment effects was assessed across subgroups of interest. We assessed safety in all participants who received at least one dose of study drug.

FINDINGS

Between March 19, 2021 and March 9, 2022, 529 people were randomly assigned in STEP-HFpEF, and between June 27, 2021 and Sept 2, 2022, 616 were randomly assigned in STEP-HFpEF DM. Overall, 1145 were included in our pooled analysis, 573 in the semaglutide group and 572 in the placebo group. Improvements in KCCQ-CSS and reductions in bodyweight between baseline and week 52 were significantly greater in the semaglutide group than in the placebo group (mean between-group difference for the change from baseline to week 52 in KCCQ-CSS 7·5 points [95% CI 5·3 to 9·8]; p<0·0001; mean between-group difference in bodyweight at week 52 -8·4% [-9·2 to -7·5]; p<0·0001). For the confirmatory secondary endpoints, 6-min walk distance (mean between-group difference at week 52 17·1 metres [9·2 to 25·0]) and the hierarchical composite endpoint (win ratio 1·65 [1·42 to 1·91]) were significantly improved, and CRP concentrations (treatment ratio 0·64 [0·56 to 0·72]) were significantly reduced, in the semaglutide group compared with the placebo group (p<0·0001 for all comparisons). For the dual primary endpoints, the efficacy of semaglutide was largely consistent across multiple subgroups, including those defined by age, race, sex, BMI, systolic blood pressure, baseline CRP, and left ventricular ejection fraction. 161 serious adverse events were reported in the semaglutide group compared with 301 in the placebo group.

INTERPRETATION

In this prespecified pooled analysis of the STEP-HFpEF and STEP-HFpEF DM trials, semaglutide was superior to placebo in improving heart failure-related symptoms and physical limitations, and reducing bodyweight in participants with obesity-related heart failure with preserved ejection fraction. These effects were largely consistent across patient demographic and clinical characteristics. Semaglutide was well tolerated.

FUNDING

Novo Nordisk.

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.

The Impact of Diabetes on Haemodynamic and Cardiometabolic Responses in Heart Failure With Preserved Ejection Fraction

AIMS

Heart failure with preserved ejection (HFpEF) and diabetes mellitus (DM) commonly co-exist. However, it is unclear if DM modifies the haemodynamic and cardiometabolic phenotype in patients with HFpEF. We aimed to interrogate the haemodynamic and cardiometabolic effects of DM in HFpEF.

METHODS

We compared the haemodynamic and metabolic profiles of non-DM patients and patients with DM-HFpEF at rest and during exercise using right heart catheterisation and mixed venous blood gas analysis.

RESULTS

Of 181 patients with HFpEF, 37 (20%) had DM. Patients with DM displayed a more adverse exercise haemodynamic response vs HFpEF alone (mean pulmonary arterial pressure: 47 mmHg [interquartile range {IQR} 42-55] vs 42 [38-47], p<0.001; workload indexed pulmonary capillary wedge pressure indexed: 0.80 mmHg/W [0.44-1.23] vs 0.57 [0.43-1.01], p=0.047). HFpEF-DM patients had a lower mixed venous oxygen saturation at rest (70% [IQR 66-73] vs 72 [69-75], p=0.003) and were unable to enhance O2 extraction to the same extent (Δ-28% [-33 to -15] vs -29 [-36 to -21], p=0.029), this occurred at a 22% lower median workload. Resting mixed venous lactate levels were higher in those with DM (1.5 mmol/L [IQR 1.1-1.9] vs 1 [0.9-1.3], p<0.001), and during exercise indexed to workload (0.09 mmol/L/W [0.06-0.13] vs 0.08 [0.05-0.11], p=0.018).

CONCLUSION

Concurrent diabetes and HFpEF was associated with greater metabolic responses at rest, with enhanced wedge driven pulmonary hypertension and relative lactataemia during exercise without appropriate augmentation of oxygen consumption.

Enhanced central sympathetic tone induces heart failure with preserved ejection fraction (HFpEF) in rats

Heart failure with preserved ejection fraction (HFpEF) is a heterogenous clinical syndrome characterized by diastolic dysfunction, concentric cardiac left ventricular (LV) hypertrophy, and myocardial fibrosis with preserved systolic function. However, the underlying mechanisms of HFpEF are not clear. We hypothesize that an enhanced central sympathetic drive is sufficient to induce LV dysfunction and HFpEF in rats. Male Sprague-Dawley rats were subjected to central infusion of either saline controls (saline) or angiotensin II (Ang II, 20 ng/min, i.c.v) via osmotic mini-pumps for 14 days to elicit enhanced sympathetic drive. Echocardiography and invasive cardiac catheterization were used to measure systolic and diastolic functions. Mean arterial pressure, heart rate, left ventricular end-diastolic pressure (LVEDP), and ± dP/dt changes in responses to isoproterenol (0.5 μg/kg, iv) were measured. Central infusion of Ang II resulted in increased sympatho-excitation with a consequent increase in blood pressure. Although the ejection fraction was comparable between the groups, there was a decrease in the E/A ratio (saline: 1.5 ± 0.2 vs Ang II: 1.2 ± 0.1). LVEDP was significantly increased in the Ang II-treated group (saline: 1.8 ± 0.2 vs Ang II: 4.6 ± 0.5). The increase in +dP/dt to isoproterenol was not significantly different between the groups, but the response in -dP/dt was significantly lower in Ang II-infused rats (saline: 11,765 ± 708 mmHg/s vs Ang II: 8,581 ± 661). Ang II-infused rats demonstrated an increased heart to body weight ratio, cardiomyocyte hypertrophy, and fibrosis. There were elevated levels of atrial natriuretic peptide and interleukin-6 in the Ang II-infused group. In conclusion, central infusion of Ang II in rats induces sympatho-excitation with concurrent diastolic dysfunction, pathological cardiac concentric hypertrophy, and cardiac fibrosis. This novel model of centrally mediated sympatho-excitation demonstrates characteristic diastolic dysfunction in rats, representing a potentially useful preclinical murine model of HFpEF to investigate various altered underlying mechanisms during HFpEF in future studies.

Effect on cardiac function among patients with type 2 diabetes following high-dose mineralocorticoid receptor antagonist using echocardiography; data from the MIRAD randomized clinical trial

BACKGROUND

Early heart failure prevention is central in patients with type 2 diabetes, and mineralocorticoid receptor antagonists (MRAs) have shown to improve prognosis. We investigated the effect of high-dose MRA, eplerenone, on cardiac function and structure in patients with type 2 diabetes and established or increased risk of cardiovascular disease but without heart failure.

METHODS

In the current randomized, placebo-controlled clinical trial, 140 patients with high-risk type 2 diabetes were randomized to high-dose eplerenone (100-200 mg daily) or placebo as add-on to standard care for 26 weeks. Left ventricular systolic and diastolic function, indexed left ventricular mass (LVMi), and global longitudinal strain (GLS) were assessed using echocardiography at baseline and after 26 weeks of treatment.

RESULTS

Of the included patients, 138 (99%) had an echocardiography performed at least once. Baseline early diastolic in-flow velocity (E-wave) indexed by mitral annulus velocity (e') was mean (SD) 11.1 (0.5), with 31% of patients reaching above 12. No effect of treatment on diastolic function was observed measured by E/e' (0.0, 95%CI [-1.2 to 1.2], P = 0.992) or E/A (-0.1, 95%CI [-0.2 to 0.0], P = 0.191). Mean left ventricular ejection fraction (LVEF) at baseline was 59.0% (8.0). No improvement in systolic function was observed when comparing groups after 26 weeks (LVEF: 0.9, 95%CI [-1.1 to 2.8], P = 0.382; GLS: -0.4%, 95%CI [-1.5 to 0.6], P = 0.422), nor in LVMi (-3.8 g/m² 95%CI [-10.2 to 2.7], P = 0.246).

CONCLUSION

In the present echo sub-study, no change in left ventricular function was observed following high-dose MRA therapy in patients with type 2 diabetes when evaluated by conventional echocardiography.

TRIAL REGISTRATION

Date of registration 25/08/2015 (EudraCT number: 2015-002,519-14).

Research Update on the Pathophysiological Mechanisms of Heart Failure with Preserved Ejection Fraction

Heart failure (HF) is a serious clinical syndrome, usually occurs at the advanced stage of various cardiovascular diseases, featured by high mortality and rehospitalization rate. According to left ventricular (LV) ejection fraction (LVEF), HF has been categorized as HF with reduced EF (HFrEF; LVEF<40%), HF with mid-range EF (HFmrEF; LVEF 40-49%), and HF with preserved EF (HFpEF; LVEF ≥50%). HFpEF accounts for about 50% of cases of heart failure and has become the dominant form of heart failure. The mortality of HFpEF is similar to that of HFrEF. There are no welldocumented treatment options that can reduce the morbidity and mortality of HFpEF now. Understanding the underlying pathological mechanisms is essential for the development of novel effective therapy options for HFpEF. In recent years, significant research progress has been achieved on the pathophysiological mechanism of HFpEF. This review aimed to update the research progress on the pathophysiological mechanism of HFpEF.

Heart Failure with Preserved Ejection Fraction: Pathogenesis, Diagnosis, Exercise, and Medical Therapies

Heart failure with preserved ejection fraction (HFpEF) accounts for more than one-half of total heart failure cases, with a high prevalence and poor prognosis, especially in older and female patients. Patients with HFpEF are characterized by hypertension, left ventricular hypertrophy, and diastolic dysfunction, and the main symptoms are dyspnea and exercise intolerance. HFpEF is currently poorly studied, and pharmacological treatment for HFpEF is still underexplored. Accumulating clinical trials have shown that exercise could exert benefits on diastolic dysfunction and quality of life in patients with HFpEF. However, there is a high limitation for applying exercise therapy due to exercise intolerance in patients with HFpEF. Key effectors of exercise-protection could be novel therapeutic targets for developing drugs to prevent and treat HFpEF. In this review article, we provide an overview of the pathogenic factors, diagnostic methods, research animal models, the mechanisms of exercise-mediated cardiac protection, and current treatments for HFpEF.

Genomic, Proteomic, and Metabolic Comparisons of Small Animal Models of Heart Failure With Preserved Ejection Fraction: A Tale of Mice, Rats, and Cats

Heart failure with preserved ejection fraction (HFpEF) remains a medical anomaly that baffles researchers and physicians alike. The overall phenotypical changes of diastolic function and left ventricular hypertrophy observed in HFpEF are definable; however, the metabolic and molecular alterations that ultimately produce these changes are not well established. Comorbidities such as obesity, hypertension, and diabetes, as well as general aging, play crucial roles in its development and progression. Various animal models have recently been developed to better understand the pathophysiological and metabolic developments in HFpEF and to illuminate novel avenues for pharmacotherapy. These models include multi‐hit rodents and feline aortic constriction animals. Recently, genomic, proteomic, and metabolomic approaches have been used to define altered signaling pathways in the heart associated with HFpEF, including those involved in inflammation, cGMP‐related, Ca²⁺ handling, mitochondrial respiration, and the unfolded protein response in endoplasmic reticulum stress. This article aims to present an overview of what has been learnt by these studies, focusing mainly on the findings in common while highlighting unresolved issues. The knowledge gained from these research models will not simply be of benefit for treating HFpEF but will undoubtedly provide new insights into the mechanisms by which the heart deals with external stresses and how the processes involved can fail.

Impact of diabetic retinopathy on prognosis of patients with heart failure with preserved ejection fraction

BACKGROUND AND AIMS

Diabetic retinopathy (DR) is one of the most common microvascular complications of diabetes mellitus (DM), and could increase the risks of adverse cardiovascular events among DM patients. Since heart failure with preserved ejection fraction (HFpEF) and DM often coexist, our present study aimed to explore the associations of DR with adverse outcomes in HFpEF patients.

METHODS AND RESULTS

We conducted this study in a large, international population suffering from HFpEF (n = 3442) based on the Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist (TOPCAT) trial. The associations of baseline DR with clinical outcomes were expressed as adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) using the Cox proportional hazard regression models. The crude incidence rates of all the outcomes studied were significantly increased when DM patients with or without DR compared to those without DM (all P < 0.05), whereas there were no differences between DM patients without DR versus those with DR (all P > 0.05). In the multivariate cox regression analysis, DR was not significantly associated with increased risks of the primary composite outcome (HR, 1.178 [95% CI, 0.870-1.596]) and secondary outcomes including all-cause death, cardiovascular death, all-cause hospitalization, hospitalization for HF, myocardial infarction, and stroke (all P > 0.05).

CONCLUSIONS

Our results of current study suggested that DM but not DR could be regarded as an independent risk factor for the prognosis of HFpEF.

CLINICAL TRIAL REGISTRATION

URL: https://clinicaltrials.gov. Unique identifier: NCT00094302.

Diabetes Mellitus and Heart Failure With Preserved Ejection Fraction: Role of Obesity

Heart failure with preserved ejection fraction is a growing epidemic and accounts for half of all patients with heart failure. Increasing prevalence, morbidity, and clinical inertia have spurred a rethinking of the pathophysiology of heart failure with preserved ejection fraction. Unlike heart failure with reduced ejection fraction, heart failure with preserved ejection fraction has distinct clinical phenotypes. The obese-diabetic phenotype is the most often encountered phenotype in clinical practice and shares the greatest burden of morbidity and mortality. Left ventricular remodeling plays a major role in its pathophysiology. Understanding the interplay of obesity, diabetes mellitus, and inflammation in the pathophysiology of left ventricular remodeling may help in the discovery of new therapeutic targets to improve clinical outcomes in heart failure with preserved ejection fraction. Anti-diabetic agents like glucagon-like-peptide 1 analogs and sodium-glucose co-transporter 2 are promising therapeutic modalities for the obese-diabetic phenotype of heart failure with preserved ejection fraction and aggressive weight loss via lifestyle or bariatric surgery is still key to reverse adverse left ventricular remodeling. This review focuses on the obese-diabetic phenotype of heart failure with preserved ejection fraction highlighting the interaction between obesity, diabetes, and coronary microvascular dysfunction in the development and progression of left ventricular remodeling. Recent therapeutic advances are reviewed.

Early cardiac-chamber-specific fingerprints in heart failure with preserved ejection fraction detected by FTIR and Raman spectroscopic techniques

The pathophysiology of heart failure with preserved ejection fraction (HFpEF) is a matter of investigation and its diagnosis remains challenging. Although the mechanisms that are responsible for the development of HFpEF are not fully understood, it is well known that nearly 80% of patients with HFpEF have concomitant hypertension. We investigated whether early biochemical alterations were detectable during HFpEF progression in salt-induced hypertensive rats, using Fourier-transformed infrared (FTIR) and Raman spectroscopic techniques as a new diagnostic approach. Greater protein content and, specifically, greater collagen deposition were observed in the left atrium and right ventricle of hypertensive rats, together with altered metabolism of myocytes. Additionally, Raman spectra indicated a conformational change, or different degree of phosphorylation/methylation, in tyrosine-rich proteins. A correlation was found between tyrosine content and cardiac fibrosis of both right and left ventricles. Microcalcifications were detected in the left and right atria of control animals, with a progressive augmentation from six to 22 weeks. A further increase occurred in the left ventricle and right atrium of 22-week salt-fed animals, and a positive correlation was shown between the mineral deposits and the cardiac size of the left ventricle. Overall, FTIR and Raman techniques proved to be sensitive to early biochemical changes in HFpEF and preceded clinical humoral and imaging markers.

Age and Sex Differences in Heart Failure With Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is a multi-organ disorder that represents about 50% of total heart failure (HF) cases and is the most common form of HF in the elderly. Because of its increasing prevalence caused by the aging population, high mortality and morbidity, and very limited therapeutic options, HFpEF is considered as one of the greatest unmet medical needs in cardiovascular medicine. Despite its complex pathophysiology, numerous preclinical models have been established in rodents and in large animals to study HFpEF pathophysiology. Although age and sex differences are well described in HFpEF population, there are knowledge gaps in sex- and age-specific differences in established preclinical models. In this review, we summarize various strategies that have been used to develop HFpEF models and discuss the knowledge gaps in sex and age differences in HFpEF.

A Preclinical Rat Model of Heart Failure With Preserved Ejection Fraction With Multiple Comorbidities

Heart failure with preserved ejection fraction (HFpEF) is a common complex clinical syndrome for which there are currently few evidence-based therapies. As patients with HFpEF very often present with comorbidities comprising the metabolic syndrome, we hypothesized, that metabolic syndrome could lead over time to the development of diastolic dysfunction and HFpEF. Obesity-prone rats were exposed to high-fat diet and compared to obesity-resistant rats fed with standard chow. Phenotyping of metabolic syndrome, associated with echocardiographic and cardiac hemodynamic measurements, was performed after 4 and 12 months. Blood and myocardial tissue sampling were performed for pathobiological evaluation. High-fat diet in obesity-prone rats elicited metabolic syndrome, characterized by increased body and abdominal fat weights, glucose intolerance and hyperlipidemia, as well as increased left ventricular (LV) systolic pressure (after 12 months). This was associated with LV diastolic dysfunction (assessed by increased LV end-diastolic pressure) and pulmonary hypertension (assessed by increased right ventricular systolic pressure). Echocardiography revealed significant concentric LV hypertrophy, while LV ejection fraction was preserved. LV remodeling was associated with cardiomyocyte hypertrophy, as well as myocardial and perivascular fibrosis. Circulating levels of soluble ST2 (the interleukin-1 receptor-like) markedly increased in rats with HFpEF, while plasma NT-proBNP levels decreased. RNA-sequencing analysis identified clusters of genes implicated in fatty acid metabolism and calcium-dependent contraction as upregulated pathways in the myocardium of rats with HFpEF. High-fat diet during 12 months in obesity-prone rats led to the development of a relevant preclinical model of HFpEF with multiple comorbidities, suitable for investigating novel therapeutic interventions.

Heart failure in diabetes

Heart failure and cardiovascular disorders represent the leading cause of death in diabetic patients. Here we present a systematic review of the main mechanisms underlying the development of diabetic cardiomyopathy. We also provide an excursus on the relative contribution of cardiomyocytes, fibroblasts, endothelial and smooth muscle cells to the pathophysiology of heart failure in diabetes. After having described the preclinical tools currently available to dissect the mechanisms of this complex disease, we conclude with a section on the most recent updates of the literature on clinical management.

Association of free fatty acid binding protein with central aortic stiffness, myocardial dysfunction and preserved ejection fraction heart failure

There is an established link between cardiometabolic abnormality, central arterial stiffness, and preserved ejection fraction heart failure (HFpEF). Adipocyte free fatty acid binding protein (a-FABP) has been shown to signal endothelial dysfunction through fatty acid toxicity, though its role in mediating ventricular-arterial dysfunction remains unclear. We prospectively examined the associations of a-FABP with central arterial pressure using non-invasive applanation tonometry (SphygmoCor) and cardiac structure/function (i.e., tissue Doppler imaging [TDI] and global longitudinal myocardial strain [GLS]) in patients with cardiometabolic (CM) risk (n = 150) and HFpEF (n = 50), with healthy volunteers (n = 49) serving as a control. We observed a graded increase of a-FABP across the healthy controls, CM individuals, and HFpEF groups (all paired p < 0.05). Higher a-FABP was independently associated with higher central systolic and diastolic blood pressures (CSP/CPP), increased arterial augmentation index (Aix), lower early myocardial relaxation velocity (TDI-e'), higher left ventricle (LV) filling (E/TDI-e') and worsened GLS (all p < 0.05). During a median of 3.85 years (interquartile range: 3.68-4.62 years) follow-up, higher a-FABP (cutoff: 24 ng/mL, adjusted hazard ratio: 1.01, 95% confidence interval: 1.001-1.02, p = 0.04) but not brain natriuretic peptide, and higher central hemodynamic indices were related to the incidence of heart failure (HF) in fully adjusted Cox models. Furthermore, a-FABP improved the HF risk classification over central hemodynamic information. We found a mechanistic pathophysiological link between a-FABP, central arterial stiffness, and myocardial dysfunction. In a population with a high metabolic risk, higher a-FABP accompanied by worsened ventricular-arterial coupling may confer more unfavorable outcomes in HFpEF.

Multiple-Tissue and Multilevel Analysis on Differentially Expressed Genes and Differentially Correlated Gene Pairs for HFpEF

Heart failure with preserved ejection fraction (HFpEF) is a complex disease characterized by dysfunctions in the heart, adipose tissue, and cerebral arteries. The elucidation of the interactions between these three tissues in HFpEF will improve our understanding of the mechanism of HFpEF. In this study, we propose a multilevel comparative framework based on differentially expressed genes (DEGs) and differentially correlated gene pairs (DCGs) to investigate the shared and unique pathological features among the three tissues in HFpEF. At the network level, functional enrichment analysis revealed that the networks of the heart, adipose tissue, and cerebral arteries were enriched in the cell cycle and immune response. The networks of the heart and adipose tissues were enriched in hemostasis, G-protein coupled receptor (GPCR) ligand, and cancer-related pathway. The heart-specific networks were enriched in the inflammatory response and cardiac hypertrophy, while the adipose-tissue-specific networks were enriched in the response to peptides and regulation of cell adhesion. The cerebral-artery-specific networks were enriched in gene expression (transcription). At the module and gene levels, 5 housekeeping DEGs, 2 housekeeping DCGs, 6 modules of merged protein–protein interaction network, 5 tissue-specific hub genes, and 20 shared hub genes were identified through comparative analysis of tissue pairs. Furthermore, the therapeutic drugs for HFpEF-targeting these genes were examined using molecular docking. The combination of multitissue and multilevel comparative frameworks is a potential strategy for the discovery of effective therapy and personalized medicine for HFpEF.

Therapeutic Stalemate in Heart Failure With Preserved Ejection Fraction

The findings of randomized trials of neurohormonal modulation have been neutral in heart failure with preserved ejection fraction and consistently positive in heart failure with reduced ejection. Left ventricular remodeling promotes the development and progression of heart failure with preserved and reduced ejection fraction. However, different stimuli mediate left ventricular remodeling that is commonly concentric in heart failure with preserved ejection fraction and eccentric in heart failure with reduced ejection. The stimuli that promote concentric left ventricular remodeling may account for the neutral findings of neuhormonal modulation in heart failure with preserved ejection fraction. Low‐grade systemic inflammation‐induced microvascular endothelial dysfunction is currently the leading hypothesis behind the development and progression of heart failure with preserved ejection fraction. The hypothesis provided the rationale for several randomized controlled trials that have led to neutral findings. The trials and their limitations are reviewed.

Right-ventricular dysfunction in HFpEF is linked to altered cardiomyocyte Ca2+ homeostasis and myofilament sensitivity

Aims

Heart failure with preserved ejection fraction (HFpEF) is frequently (30%) associated with right ventricular (RV) dysfunction, which increases morbidity and mortality in these patients. Yet cellular mechanisms of RV remodelling and RV dysfunction in HFpEF are not well understood. Here, we evaluated RV cardiomyocyte function in a rat model of metabolically induced HFpEF.

Methods and results

Heart failure with preserved ejection fraction‐prone animals (ZSF‐1 obese) and control rats (Wistar Kyoto) were fed a high‐caloric diet for 13 weeks. Haemodynamic characterization by echocardiography and invasive catheterization was performed at 22 and 23 weeks of age, respectively. After sacrifice, organ morphometry, RV histology, isolated RV cardiomyocyte function, and calcium (Ca²⁺) transients were assessed. ZSF‐1 obese rats showed a HFpEF phenotype with left ventricular (LV) hypertrophy, LV diastolic dysfunction (including increased LV end‐diastolic pressures and E/e′ ratio), and preserved LV ejection fraction. ZSF‐1 obese animals developed RV dilatation (50% increased end‐diastolic area) and mildly impaired RV ejection fraction (42%) with evidence of RV hypertrophy. In isolated RV cardiomyocytes from ZSF‐1 obese rats, cell shortening amplitude was preserved, but cytosolic Ca²⁺ transient amplitude was reduced. In addition, augmentation of cytosolic Ca²⁺ release with increased stimulation frequency was lost in ZSF‐1 obese rats. Myofilament sensitivity was increased, while contractile kinetics were largely unaffected in intact isolated RV cardiomyocytes from ZSF‐1 obese rats. Western blot analysis revealed significantly increased phosphorylation of cardiac myosin‐binding protein C (Ser282 cMyBP‐C) but no change in phosphorylation of troponin I (Ser23, 24 TnI) in RV myocardium from ZSF‐1 obese rats.

Conclusions

Right ventricular dysfunction in obese ZSF‐1 rats with HFpEF is associated with intrinsic RV cardiomyocyte remodelling including reduced cytosolic Ca²⁺ amplitudes, loss of frequency‐dependent augmentation of Ca²⁺ release, and increased myofilament Ca²⁺ sensitivity.

Association of Midlife Cardiovascular Risk Factors With the Risk of Heart Failure Subtypes Later in Life

BACKGROUND

Independent associations between cardiovascular risk factor exposures during midlife and later life development of heart failure (HF) with preserved ejection fraction (HFpEF) versus reduced EF (HFrEF) have not been previously studied.

METHODS

We pooled data from 4 US cohort studies (Atherosclerosis Risk in Communities, Cardiovascular Health, Health , Aging and Body Composition, and Multi-Ethnic Study of Atherosclerosis) and imputed annual risk factor trajectories for body mass index, systolic and diastolic blood pressure, low-density lipoprotein and high-density lipoprotein cholesterol, and glucose starting from age 40 years. Time-weighted average exposures to each risk factor during midlife and later life were calculated and analyzed for associations with the development of HFpEF or HFrEF.

RESULTS

A total of 23,861 participants were included (mean age at first in-person visit, 61.8 ±1 0.2 years; 56.6% female). During a median follow-up of 12 years, there were 3666 incident HF events, of which 51% had EF measured, including 934 with HFpEF and 739 with HFrEF. A high midlife systolic blood pressure and low midlife high-density lipoprotein cholesterol were associated with HFrEF, and a high midlife body mass index, systolic blood pressure, pulse pressure, and glucose were associated with HFpEF. After adjusting for later life exposures, only midlife pulse pressure remained independently associated with HFpEF.

CONCLUSIONS

Midlife exposure to cardiovascular risk factors are differentially associated with HFrEF and HFpEF later in life. Having a higher pulse pressure during midlife is associated with a greater risk for HFpEF but not HFrEF, independent of later life exposures.

Gasotransmitter signaling in energy homeostasis and metabolic disorders

Gasotransmitters are small molecules of gases, including nitric oxide (NO), hydrogen sulfide (H₂S), and carbon monoxide (CO). These three gasotransmitters can be endogenously produced and regulate a wide range of pathophysiological processes by interacting with specific targets upon diffusion in the biological media. By redox and epigenetic regulation of various physiological functions, NO, H₂S, and CO are critical for the maintenance of intracellular energy homeostasis. Accumulated evidence has shown that these three gasotransmitters control ATP generation, mitochondrial biogenesis, glucose metabolism, insulin sensitivity, lipid metabolism, and thermogenesis, etc. Abnormal generation and metabolism of NO, H₂S, and/or CO are involved in various abnormal metabolic diseases, including obesity, diabetes, and dyslipidemia. In this review, we summarized the roles of NO, H₂S, and CO in the regulation of energy homeostasis as well as their involvements in the metabolism of dysfunction-related diseases. Understanding the interaction among these gasotransmitters and their specific molecular targets are very important for therapeutic applications.

Confirmation of the Cardioprotective Effect of MitoGamide in the Diabetic Heart

Purpose

HFpEF (heart failure with preserved ejection fraction) is a major consequence of diabetic cardiomyopathy with no effective treatments. Here, we have characterized Akita mice as a preclinical model of HFpEF and used it to confirm the therapeutic efficacy of the mitochondria-targeted dicarbonyl scavenger, MitoGamide.

Methods and Results

A longitudinal echocardiographic analysis confirmed that Akita mice develop diastolic dysfunction with reduced E peak velocity, E/A ratio and extended isovolumetric relaxation time (IVRT), while the systolic function remains comparable with wild-type mice. The myocardium of Akita mice had a decreased ATP/ADP ratio, elevated mitochondrial oxidative stress and increased organelle density, compared with that of wild-type mice. MitoGamide, a mitochondria-targeted 1,2-dicarbonyl scavenger, exhibited good stability in vivo, uptake into cells and mitochondria and reactivity with dicarbonyls. Treatment of Akita mice with MitoGamide for 12 weeks significantly improved the E/A ratio compared with the vehicle-treated group.

Conclusion

Our work confirms that the Akita mouse model of diabetes replicates key clinical features of diabetic HFpEF, including cardiac and mitochondrial dysfunction. Furthermore, in this independent study, MitoGamide treatment improved diastolic function in Akita mice.

Electronic supplementary material

The online version of this article (10.1007/s10557-020-07086-7) contains supplementary material, which is available to authorized users.

Bone marrow contribution to the heart from development to adulthood

Cardiac chamber walls contain large numbers of non-contractile interstitial cells, including fibroblasts, endothelial cells, pericytes and significant populations of blood lineage-derived cells. Blood cells first colonize heart tissues a few days before birth, although their recruitment from the bloodstream to the cardiac interstitium is continuous and extends throughout adult life. The bone marrow, as the major hematopoietic site of adult individuals, is in charge of renewing all circulating cell types, and it therefore plays a pivotal role in the incorporation of blood cells to the heart. Bone marrow-derived cells are instrumental to tissue homeostasis in the steady-state heart, and are major effectors in cardiac disease progression. This review will provide a comprehensive approach to bone marrow-derived blood cell functions in the heart, and discuss aspects related to hot topics in the cardiovascular field like cell-based heart regeneration strategies.

Deficit of resolution receptor magnifies inflammatory leukocyte directed cardiorenal and endothelial dysfunction with signs of cardiomyopathy of obesity

Chronic unresolved inflammation is the primary determinant of cardiovascular disease. Precise mechanisms that define the genesis of unresolved inflammation in heart failure with preserved ejection fraction (HFpEF) are of interest due to the obesity epidemic. To examine the obesity phenotype and its direct/indirect consequences, multiple approaches were employed using the lipoxin receptor (abbreviated as ALX) dysfunction mouse model. Indirect calorimetry analyses revealed that the deletion of ALX dysregulated energy metabolism driving toward age-related obesity. Heart function data suggest that obesity-prone ALX deficient mice had impaired myocardium strain. Comprehensive measurement of chemokines, extracellular matrix, and arrhythmogenic arrays confirmed the dysregulation of multiple ion channels gene expression with amplified inflammatory chemokines and cytokines response at the age of 4 months compared with WT counterparts. Quantitative analyses of leukocytes demonstrated an increase of proinflammatory Ly6C^hi CCR2⁺ macrophages in the spleen and heart at a steady-state resulting in an inflamed splenocardiac axis. Signs of subtle inflammation were marked with cardiorenal, endothelial defects with decreased CD31 and eNOS and an increased iNOS and COX2 expression. Thus, ALX receptor deficiency serves as an experimental model that defines multiple cellular and molecular mechanisms in HFpEF that could be a target for the development of HFpEF therapy in cardiovascular medicine.

Negative synergism of diabetes mellitus and obesity in patients with heart failure with preserved ejection fraction: a cardiovascular magnetic resonance study

In patients with heart failure with preserved ejection fraction (HFpEF), diabetes mellitus (DM) and obesity are important comorbidities as well as major risk factors. Their conjoint impact on the myocardium provides insight into the HFpEF aetiology. We sought to investigate the association between obesity, DM, and their combined effect on alterations in the myocardial tissue in HFpEF patients. One hundred and sixty-two HFpEF patients (55 ± 12 years, 95 men) and 45 healthy subjects (53 ± 12 years, 27 men) were included. Patients were classified according to comorbidity prevalence (36 obese patients without DM, 53 diabetic patients without obesity, and 73 patients with both). Myocardial remodeling, fibrosis, and longitudinal contractility were quantified with cardiovascular magnetic resonance imaging using cine and myocardial native T₁ images. Patients with DM and obesity had impaired global longitudinal strain (GLS) and increased myocardial native T₁ compared to patients with only one comorbidity (DM + Obesity vs. DM and Obesity; GLS, - 15 ± 2.1 vs - 16.5 ± 2.4 and - 16.7 ± 2.2%; native T₁, 1162 ± 37 vs 1129 ± 25 and 1069 ± 29 ms; P < 0.0001 for all). A negative synergistic effect of combined obesity and DM prevalence was observed for native T₁ (np² = 0.273, p = 0.002) and GLS (np² = 0.288, p < 0.0001). Additionally, severity of insulin resistance was associated with GLS (R = 0.590, P < 0.0001), and native T₁ (R = 0.349, P < 0.0001). The conjoint effect of obesity and DM in HFpEF patients is associated with diffuse myocardial fibrosis and deterioration in GLS. The negative synergistic effects observed on the myocardium may be related to severity of insulin resistance.

Carotid arterial mechanics as useful biomarker of extracellular matrix turnover and preserved ejection fraction heart failure

Aims

We aimed to investigate the functional alterations, diagnostic utilization, and prognostic implication of carotid arterial deformations in subjects with cardiovascular risk factors and heart failure (HF) with preserved ejection fraction (HFpEF).

Methods and results

Among 251 prospectively participants (mean age 66.0 ± 9.8 years, 65.7% female) in a single centre between December 2011 and September 2014, carotid artery deformations including circumferential strain (CCS)/strain rate and radial strain were analysed by two‐dimensional speckle tracking. We further related these carotid artery deformation indices to HF biomarkers and cardiac structure and function by echocardiography and explored their prognostic values. Significant reductions of CCS, circumferential strain rate, and circumferential radial strain were observed across control (n = 52), high risk (n = 147), and HFpEF (n = 52) (trend P ≤ 0.001). Aging, hypertension, HFpEF, and higher pulse rate showed independent associations with reduced CCS by stepwise multivariate regressions (all P < 0.05). Higher CCS was inversely associated with better cardiac remodelling and functional indices, and lower multiple HF biomarkers (all P ≤ 0.005). After adjustment, higher CCS was independently associated with better global ventricular longitudinal strain/early diastolic strain rate, lower matrix metalloproteinase‐2, and N‐terminal propeptide of procollagen type III levels (adjusted coef: −0.08 and −19.9, all P < 0.05). During a median follow‐up of 1406 days (interquartile range: 1342‑1720 days), CCS less than 3.28% as a cut‐off had markedly higher HF events [Harrell's C: 0.72, adjusted HR: 2.20 (95% confidence interval: 1.24, 3.16), P = 0.008]. CCS also showed significantly improved risk prediction for HF over global ventricular longitudinal strain (net reclassification index: 48%, P = 0.001; integrated discrimination improvement: 1.8%, P < 0.001).

Conclusions

Carotid artery deformations using two‐dimensional speckle‐tracking imaging showed novel mechanistic insights on functional arterial alterations reflecting coupled arterial‐ventricular pathophysiology. Utilization of such measure may further provide additive prognostic value to advanced myocardial functional assessment.

Both male and female obese ZSF1 rats develop cardiac dysfunction in obesity-induced heart failure with preserved ejection fraction

Heart failure with a preserved ejection fraction (HFpEF) is associated with multiple comorbidities, such as old age, hypertension, type 2 diabetes and obesity and is more prevalent in females. Although the male obese ZSF1 rat has been proposed as a suitable model to study the development of diastolic dysfunction and early HFpEF, studies in female animals have not been performed yet. Therefore, we aimed to characterize the cardiac phenotype in female obese ZSF1 rats and their lean counterparts. Additionally, we aimed to investigate whether differences exist in disease progression in obese male and female ZSF1 rats. Therefore, male and female ZSF1 rats, lean as well as obese (N = 6-9/subgroup), were used. Every two weeks, from 12 to 26 weeks of age, systolic blood pressure and echocardiographic measurements were performed, and venous blood was sampled. Female obese ZSF1 rats, as compared to female lean ZSF1 rats, developed diastolic dysfunction with cardiac hypertrophy and fibrosis in the presence of severe dyslipidemia, increased plasma growth differentiation factor 15 and mild hypertension, and preservation of systolic function. Although obese female ZSF1 rats did not develop hyperglycemia, their diastolic dysfunction was as severe as in the obese males. Taken together, the results from the present study suggest that the female obese ZSF1 rat is a relevant animal model for HFpEF with multiple comorbidities, suitable for investigating novel therapeutic interventions.

Overlapping pathogenic signalling pathways and biomarkers in preeclampsia and cardiovascular disease

OBJECTIVES

Preeclampsia is a cardiovascular pregnancy complication that occurs in 5-10% of pregnancies and it can lead to a number of pregnancy complications including maternal and foetal death. Long-term, preeclampsia is associated with up to 8-fold increased risk of cardiovascular disease (CVD) for both mothers and their offspring. The lack of mechanistic data in relation to the causes or consequences of preeclampsia has prevented the development of effective therapeutic and monitoring strategies.

STUDY DESIGN

This study investigates common underlying mechanisms of preeclampsia and CVD, specifically hypertension and heart failure with preserved ejection fraction (HFpEF), using "in silico" approach of publicly available datasets. Integrated techniques were designed to mine data repositories and identify relevant biomarkers associated with these three conditions.

MAIN OUTCOMES MEASURES

The knowledge base tools were employed that enabled the analysis of these biomarkers to discover potential molecular and biological links between these three conditions.

RESULTS

Our bioinformatics "in silico" analyses of the publically available datasets identified 76 common biomarkers between preeclampsia, hypertension and HFpEF. These biomarkers were representative of 29 pathways commonly enriched across the three conditions which were largely related to inflammation, metabolism, angiogenesis, remodelling, haemostasis, apoptosis and the renin-angiotensin-aldosterone (RAAS) system.

CONCLUSIONS

This bioinformatics approach uses the wealth of scientific data available in public repositories to gain a deeper understanding of the overlapping pathogenic mechanisms of associated diseases, which could be explored as biomarkers or targets to prevent long-term cardiovascular complications such as hypertension and HFpEF following preeclampsia.

Role of Leptin in Cardiovascular Diseases

The adipocyte-derived adipokine leptin exerts pleiotropic effects, which are essential for the regulation of energy balance and cell metabolism, for controlling inflammatory and immune responses, and for the maintenance of homeostasis of the cardiovascular system. Leptin resistance in obese or type 2 diabetes mellitus (T2DM) patients is defined as a decrease in tissue response to leptin. In the cardiovascular system, leptin resistance exhibits the adverse effect on the heart's response to stress conditions and promoting cardiac remodeling due to impaired cardiac metabolism, increased fibrosis, vascular dysfunction, and enhanced inflammation. Leptin resistance or leptin signaling deficiency results in the risk increase of cardiac dysfunction and heart failure, which is a leading cause of obesity- and T2DM-related morbidity and mortality. Animal studies using leptin- and leptin receptor- (Lepr) deficient rodents have provided many useful insights into the underlying molecular and pathophysiological mechanisms of obese- and T2DM-associated metabolic and cardiovascular diseases. However, none of the animal models used so far can fully recapitulate the phenotypes of patients with obese or T2DM. Therefore, the role of leptin in the human cardiovascular system, and whether leptin affects cardiac function directly or acts through a leptin-regulated neurohumoral pathway, remain elusive. As the prevalence of obesity and diabetes is continuously increasing, strategies are needed to develop and apply human cell-based models to better understand the precise role of leptin directly in different cardiac cell types and to overcome the existing translational barriers. The purpose of this review is to discuss the mechanisms associated with leptin signaling deficiency or leptin resistance in the development of metabolic and cardiovascular diseases. We analyzed and comprehensively addressed substantial findings in pathophysiological mechanisms in commonly used leptin- or Lepr-deficient rodent models and highlighted the differences between rodents and humans. This may open up new strategies to develop directly and reliably applicable models, which resemble the human pathophysiology in order to advance health care management of obesity- and T2DM-related cardiovascular complications.

Pathophysiological understanding of HFpEF: microRNAs as part of the puzzle

Half of all heart failure patients have preserved ejection fraction (HFpEF). Comorbidities associated with and contributing to HFpEF include obesity, diabetes and hypertension. Still, the underlying pathophysiological mechanisms of HFpEF are unknown. A preliminary consensus proposes that the multi-morbidity triggers a state of systemic, chronic low-grade inflammation, and microvascular dysfunction, causing reduced nitric oxide bioavailability to adjacent cardiomyocytes. As a result, the cardiomyocyte remodels its contractile elements and fails to relax properly, causing diastolic dysfunction, and eventually HFpEF. HFpEF is a complex syndrome for which currently no efficient therapies exist. This is notably due to the current one-size-fits-all therapy approach that ignores individual patient differences. MicroRNAs have been studied in relation to pathophysiological mechanisms and comorbidities underlying and contributing to HFpEF. As regulators of gene expression, microRNAs may contribute to the pathophysiology of HFpEF. In addition, secreted circulating microRNAs are potential biomarkers and as such, they could help stratify the HFpEF population and open new ways for individualized therapies. In this review, we provide an overview of the ever-expanding world of non-coding RNAs and their contribution to the molecular mechanisms underlying HFpEF. We propose prospects for microRNAs in stratifying the HFpEF population. MicroRNAs add a new level of complexity to the regulatory network controlling cardiac function and hence the understanding of gene regulation becomes a fundamental piece in solving the HFpEF puzzle.

Epicardial Adipose Tissue and Cardiovascular Disease

PURPOSE OF REVIEW

Epicardial adipose tissue has been associated with the development/progression of cardiovascular disease. We appraise the strength of the association between epicardial adipose tissue and development/progression of cardiovascular diseases like coronary artery disease, atrial fibrillation, and heart failure with preserved ejection fraction.

RECENT FINDINGS

Cross-sectional clinical and translational correlative studies have established an association between epicardial adipose tissue and progression of coronary artery disease. Recent studies question this association and underline the need for longitudinal studies. Epicardial adipose tissue also plays a definite role in the pathobiology of atrial fibrillation and its recurrence after ablation. In contrast to an early paradigm, epicardial adipose tissue does not appear to play a key role in the pathogenesis of heart failure with preserved ejection fraction in obese patients. The association of epicardial adipose tissue with atrial fibrillation is robust. In contrast, the association of epicardial adipose tissue with coronary artery disease and heart failure with preserved ejection fraction is tenuous. Additional research, including longitudinal studies, is needed to confirm or refute these proposed associations.

Conflicting vascular and metabolic impact of the IL-33/sST2 axis

Interleukin 33 (IL-33), which is expressed by several immune cell types, endothelial and epithelial cells, and fibroblasts, is a cytokine of the IL-1 family that acts both intra- and extracellularly to either enhance or resolve the inflammatory response. Intracellular IL-33 acts in the nucleus as a regulator of transcription. Once released from cells by mechanical stress, inflammatory cytokines, or necrosis, extracellular IL-33 is proteolytically processed to act in an autocrine/paracrine manner as an 'alarmin' on neighbouring or various immune cells expressing the ST2 receptor. Thus, IL-33 may serve an important role in tissue preservation and repair in response to injury; however, the actions of IL-33 are dampened by a soluble form of ST2 (sST2) that acts as a decoy receptor and is produced by endothelial and certain immune cells. Accumulating evidence supports the conclusion that sST2 is a biomarker of vascular health with diagnostic and/or prognostic value in various cardiovascular diseases, including coronary artery disease, myocardial infarction, atherosclerosis, giant-cell arteritis, acute aortic dissection, and ischaemic stroke, as well as obesity and diabetes. Although sST2 levels are positively associated with cardiovascular disease severity, the assumption that IL-33 is always beneficial is naïve. It is increasingly appreciated that the pathophysiological importance of IL-33 is highly dependent on cellular and temporal expression. Although IL-33 is atheroprotective and may prevent obesity and type 2 diabetes by regulating lipid metabolism, IL-33 appears to drive endothelial inflammation. Here, we review the current knowledge of the IL-33/ST2/sST2 signalling network and discuss its pathophysiological and translational implications in cardiovascular diseases.

Upregulation of Myocardial and Vascular Phosphodiesterase 9A in A Model of Atherosclerotic Cardiovascular Disease

Atherosclerosis is strongly associated with cardiac dysfunction and heart failure. Besides microvascular dysfunction and diminishment of the cardiac nitric oxide-Protein Kinase G (NO-PKG) pathway, recent evidence suggests that phosphodiesterase 9A (PDE9A) enzyme has an unfavorable role in pathological changes. Here, we characterized a rabbit model that shows cardiac dysfunction as a result of an atherogenic diet, and examined the myocardial PDE9A signaling. Rabbits were divided into Control (normal diet) and HC (atherogenic diet) groups. Cardiac function was evaluated by echocardiography. Vascular function was assessed, along with serum biomarkers. Histological stains were conducted, expression of selected proteins and cyclic guanosine monophosphate (cGMP) levels were determined. Signs of diastolic dysfunction were shown in HC animals, along with concentric hypertrophy and interstitial fibrosis. Endothelial function was diminished in HC rabbits, along with marked reduction in the aortic lumen, and increased left ventricle outflow tract (LVOT) pressures. A significant increase was shown in myocardial PDE9A levels in HC animals with unchanged vasodilator-stimulated phosphoprotein (VASP) phosphorylation and cGMP levels. Upregulation of PDE9A may be associated with early stage of cardiac dysfunction in atherosclerotic conditions. Since PDE9A is involved in cGMP degradation and in deactivation of the cardioprotective PKG signaling pathway, it may become an encouraging target for future investigations in atherosclerotic diseases.

Do sodium-glucose co-transporter-2 inhibitors prevent heart failure with a preserved ejection fraction by counterbalancing the effects of leptin? A novel hypothesis

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce the risk of serious heart failure events in patients with type 2 diabetes, but little is known about mechanisms that might mediate this benefit. The most common heart failure phenotype in type 2 diabetes is obesity-related heart failure with a preserved ejection fraction (HFpEF). It has been hypothesized that the synthesis of leptin in this disorder leads to sodium retention and plasma volume expansion as well as to cardiac and renal inflammation and fibrosis. Interestingly, leptin-mediated neurohormonal activation appears to enhance the expression of SGLT2 in the renal tubules, and SGLT2 inhibitors exert natriuretic actions at multiple renal tubular sites in a manner that can oppose the sodium retention produced by leptin. In addition, SGLT2 inhibitors reduce the accumulation and inflammation of perivisceral adipose tissue, thus minimizing the secretion of leptin and its paracrine actions on the heart and kidneys to promote fibrosis. Such fibrosis probably contributes to the impairment of cardiac distensibility and glomerular function that characterizes obesity-related HFpEF. Ongoing clinical trials with SGLT2 inhibitors in heart failure are positioned to confirm or refute the hypothesis that these drugs may favourably influence the course of obesity-related HFpEF by their ability to attenuate the secretion and actions of leptin.

Epicardial Adipose Tissue May Mediate Deleterious Effects of Obesity and Inflammation on the Myocardium

Epicardial adipose tissue has unique properties that distinguish it from other depots of visceral fat. Rather than having distinct boundaries, the epicardium shares an unobstructed microcirculation with the underlying myocardium, and in healthy conditions, produces cytokines that nourish the heart. However, in chronic inflammatory disorders (especially those leading to heart failure with preserved ejection fraction), the epicardium becomes a site of deranged adipogenesis, leading to the secretion of proinflammatory adipokines that can cause atrial and ventricular fibrosis. Accordingly, in patients at risk of heart failure with preserved ejection fraction, drugs that promote the accumulation or inflammation of epicardial adipocytes may lead to heart failure, whereas treatments that ameliorate the proinflammatory characteristics of epicardial fat may reduce the risk of heart failure. These observations suggest that epicardial adipose tissue is a transducer of the adverse effects of systemic inflammation and metabolic disorders on the heart, and thus, represents an important target for therapeutic interventions.

Augmentation of glucagon-like peptide-1 receptor signalling by neprilysin inhibition: potential implications for patients with heart failure

Augmentation of glucagon-like peptide-1 (GLP-1) receptor signalling is an established approach to the treatment of type 2 diabetes. However, endogenous GLP-1 and long-acting GLP-1 receptor analogues are degraded not only by dipeptidyl peptidase-4, but also by neprilysin. This observation raises the possibilities that endogenous GLP-1 contributes to the clinical effects of neprilysin inhibition and that patients concurrently treated with sacubitril/valsartan and incretin-based drugs may experience important drug-drug interactions. Specifically, potentiation of GLP-1 receptor signalling may underlie the antihyperglycaemic actions of sacubitril/valsartan. Neprilysin inhibitors may also be able to augment the effects of long-acting GLP-1 analogues to increase heart rate and myocardial cyclic AMP, and thus, potentiate these deleterious actions; if so, concomitant treatment with GLP-1 receptor agonists may limit the efficacy of neprilysin inhibitors in patients with both heart failure and diabetes. For patients not concurrently treated with GLP-1 analogues, the action of neprilysin to enhance the effects of GLP-1 may be particularly relevant in the brain, where augmentation of GLP-1 and other endogenous peptides may act to inhibit amyloid-induced neuroinflammation and cytotoxicity and improve memory formation and executive functioning. Experimentally, neprilysin inhibitors may also potentiate the effects of endogenous GLP-1 and GLP-1 receptor agonists on blood vessels and the kidney. The role of neprilysin in the metabolism of endogenous GLP-1 and long-acting GLP-1 analogues points to a range of potential pathophysiological effects that may be clinically relevant to patients with heart failure, with or without diabetes.

Are the effects of drugs to prevent and to treat heart failure always concordant? The statin paradox and its implications for understanding the actions of antidiabetic medications

Most treatments for chronic heart failure are effective both in preventing its onset and reducing its progression. However, statins prevent the development of heart failure, but they do not decrease morbidity and mortality in those with established heart failure. This apparent discordance cannot be explained by an effect to prevent interval myocardial infarctions. Instead, it seems that the disease that statins were preventing in trials of patients with a metabolic disorder was different from the disease that they were treating in trials of chronic heart failure. The most common phenotype of heart failure in patients with obesity and diabetes is heart failure with a preserved ejection fraction (HFpEF). In this disorder, the anti-inflammatory effects of statins might ameliorate myocardial fibrosis and cardiac filling abnormalities, but these actions may have little relevance to patients with heart failure and a reduced ejection fraction (HFrEF), whose primary derangement is cardiomyocyte loss and stretch. These distinctions may explain why statins were ineffective in trials that focused on HFrEF, but have been reported to produce favourable effects in observational studies of HFpEF. Similarly, selective cytokine antagonists were ineffective in HFrEF, but have been associated with benefits in HFpEF. These observations may have important implications for our understanding of the effects of antihyperglycaemic medications. Glucagon-like peptide-1 receptor agonists have had neutral effects on heart failure events in people at risk for HFpEF, but have exerted deleterious actions in HFrEF. Similarly, sodium-glucose co-transporter 2 inhibitors, which exert anti-inflammatory effects and reduce heart failure events in patients who are prone to HFpEF, may not be effective in HFrEF. The distinctions between HFrEF and HFpEF may explain why the effects of drugs on heart failure events in diabetes trials may not be relevant to their use in patients with systolic dysfunction.

Obesity-Related Heart Failure With a Preserved Ejection Fraction: The Mechanistic Rationale for Combining Inhibitors of Aldosterone, Neprilysin, and Sodium-Glucose Cotransporter-2

Obesity-related heart failure with a preserved ejection fraction (HFpEF) is an important phenotype prevalent in the community, especially in people with metabolic disorders (e.g., dyslipidemia, diabetes). These individuals exhibit a marked expansion of plasma volume, but ventricular distensibility is limited, most likely as a result of cardiac microvascular rarefaction acting in concert with myocardial and pericardial fibrosis. Consequently, the increase in plasma volume causes a disproportionate increase in cardiac filling pressures, leading to heart failure, even though systolic ejection is not impaired. The features of this syndrome appear to be related (in part) to the overproduction of adipocyte-derived cell-signaling molecules, including aldosterone and neprilysin. The resulting sodium retention and plasma volume expansion is exacerbated by their mutual actions to promote cardiac and systemic inflammation and fibrosis. Inhibitors of aldosterone, neprilysin, and the sodium-glucose transporter-2 (SGLT2) can ameliorate the plasma volume expansion and pro-inflammatory and profibrotic pathways, potentially opposing the action of diverse adipocytokines. All 3 classes of drugs can reduce the quantity of visceral adipose tissue and ameliorate its abnormal biological properties. This mechanistic framework is supported by the results of large-scale randomized trials with mineralocorticoid receptor antagonists and SGLT2 inhibitors and is being further tested in an ongoing large-scale trial of neprilysin inhibition. The promise of using mineralocorticoid receptor antagonists, neprilysin inhibitors, and SGLT2 inhibitors (alone or in combination) in the management of obesity-related HFpEF suggests that physicians might finally have a phenotype of HFpEF that they can understand and treat.

Heart Failure With Preserved Ejection Fraction in Diabetes: Mechanisms and Management

Diabetes mellitus (DM) is a major cause of heart failure in the Western world, either secondary to coronary artery disease or from a distinct entity known as "diabetic cardiomyopathy." Furthermore, heart failure with preserved ejection fraction (HFpEF) is emerging as a significant clinical problem for patients with DM. Current clinical data suggest that between 30% and 40% of patients with HFpEF suffer from DM. The typical structural phenotype of the HFpEF heart consists of endothelial dysfunction, increased interstitial and perivascular fibrosis, cardiomyocyte stiffness, and hypertrophy along with advanced glycation end products deposition. There is a myriad of mechanisms that result in the phenotypical HFpEF heart including impaired cardiac metabolism and substrate utilization, altered insulin signalling leading to protein kinase C activation, advanced glycated end products deposition, prosclerotic cytokine activation (eg, transforming growth factor-β activation), along with impaired nitric oxide production from the endothelium. Moreover, recent investigations have focused on the role of endothelial-myocyte interactions. Despite intense research, current therapeutic strategies have had little effect on improving morbidity and mortality in patients with DM and HFpEF. Possible explanations for this include a limited understanding of the role that direct cell-cell communication or indirect cell-cell paracrine signalling plays in the pathogenesis of DM and HFpEF. Additionally, integrins remain another important mediator of signals from the extracellular matrix to cells within the failing heart and might play a significant role in cell-cell cross-talk. In this review we discuss the characteristics and mechanisms of DM and HFpEF to stimulate potential future research for patients with this common, and morbid condition.

In Silico Analysis of Differential Gene Expression in Three Common Rat Models of Diastolic Dysfunction

Standard therapies for heart failure with preserved ejection fraction (HFpEF) have been unsuccessful, demonstrating that the contribution of the underlying diastolic dysfunction pathophysiology differs from that of systolic dysfunction in heart failure and currently is far from being understood. Complicating the investigation of HFpEF is the contribution of several comorbidities. Here, we selected three established rat models of diastolic dysfunction defined by three major risk factors associated with HFpEF and researched their commonalities and differences. The top differentially expressed genes in the left ventricle of Dahl salt sensitive (Dahl/SS), spontaneous hypertensive heart failure (SHHF), and diabetes 1 induced HFpEF models were derived from published data in Gene Expression Omnibus and used for a comprehensive interpretation of the underlying pathophysiological context of each model. The diversity of the underlying transcriptomic of the heart of each model is clearly observed by the different panel of top regulated genes: the diabetic model has 20 genes in common with the Dahl/SS and 15 with the SHHF models. Advanced analytics performed in Ingenuity Pathway Analysis (IPA^®) revealed that Dahl/SS heart tissue transcripts triggered by upstream regulators lead to dilated cardiomyopathy, hypertrophy of heart, arrhythmia, and failure of heart. In the heart of SHHF, a total of 26 genes were closely linked to cardiovascular disease including cardiotoxicity, pericarditis, ST-elevated myocardial infarction, and dilated cardiomyopathy. IPA Upstream Regulator analyses revealed that protection of cardiomyocytes is hampered by inhibition of the ERBB2 plasma membrane-bound receptor tyrosine kinases. Cardioprotective markers such as natriuretic peptide A (NPPA), heat shock 27 kDa protein 1 (HSPB1), and angiogenin (ANG) were upregulated in the diabetes 1 induced model; however, the model showed a different underlying mechanism with a majority of the regulated genes involved in metabolic disorders. In conclusion, our findings suggest that multiple mechanisms may contribute to diastolic dysfunction and HFpEF, and thus drug therapies may need to be guided more by phenotypic characteristics of the cardiac remodeling events than by the underlying molecular processes.

Pharmacological Management of a Heart Failure Patient with Severe Obesity

Obesity is one of the commonest comorbidities in patients with heart failure, and it is associated with increased mortality risk. However, obese patients are often underrepresented in clinical trials and therefore evidence on their management remains scant. In order to expand knowledge on the management of these patients, anecdotal reports may be considered. In the present case report, we discuss the successful management of an obese patient who received sacubitril/valsartan therapy. This treatment was initiated after a 12-month period of losartan therapy, which did not provide any benefit in terms of heart function. Importantly, during this period the patient required frequent hospitalizations, with a marked decrease in quality of life. After the switch to sacubitril/valsartan, a 10% increase in left ventricular ejection fraction was observed (from 30 to 40%) over a 12-month period. Moreover, no hospitalizations were required, and the patient was able to carry on at least some of his daily activities.