Limited synergy of obesity and hypertension, prevalent risk factors in onset and progression of heart failure with preserved ejection fraction

Myocardial Metabolic Reprogramming in HFpEF

Heart failure (HF) caused by structural or functional cardiac abnormalities is a significant cause of morbidity and mortality worldwide. While HF with reduced ejection fraction (HErEF) is well understood, more than half of patients have HF with preserved ejection fraction (HFpEF). Currently, the treatment for HFpEF primarily focuses on symptom alleviation, lacking specific drugs. The stressed heart undergoes metabolic switches in substrate preference, which is a compensatory process involved in cardiac pathological remodeling. Although metabolic reprogramming in HF has gained attention in recent years, its role in HFpEF still requires further elucidation. In this review, we present a summary of cardiac mitochondrial dysfunction and cardiac metabolic reprogramming in HFpEF. Additionally, we emphasize potential therapeutic approaches that target metabolic reprogramming for the treatment of HFpEF.

Animal models of heart failure with preserved ejection fraction (HFpEF): from metabolic pathobiology to drug discovery

Heart failure (HF) with preserved ejection fraction (HFpEF) is currently a preeminent challenge for cardiovascular medicine. It has a poor prognosis, increasing mortality, and is escalating in prevalence worldwide. Despite accounting for over 50% of all HF patients, the mechanistic underpinnings driving HFpEF are poorly understood, thus impeding the discovery and development of mechanism-based therapies. HFpEF is a disease syndrome driven by diverse comorbidities, including hypertension, diabetes and obesity, pulmonary hypertension, aging, and atrial fibrillation. There is a lack of high-fidelity animal models that faithfully recapitulate the HFpEF phenotype, owing primarily to the disease heterogeneity, which has hampered our understanding of the complex pathophysiology of HFpEF. This review provides an updated overview of the currently available animal models of HFpEF and discusses their characteristics from the perspective of energy metabolism. Interventional strategies for efficiently utilizing energy substrates in preclinical HFpEF models are also discussed.

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.

Factors associated with the intermediate probability of heart failure with preserved ejection fraction on the H₂FPEF score in asymptomatic patients in rotation work conditions in the Arctic

Aim. To study the factors associated with the intermediate probability of heart failure (HF) with preserved ejection fraction (HFpEF) according to the H2FPEF score (Heavy; Hypertensive; Atrial Fibrillation; Pulmonary Hypertension; Elder; Filling Pressure) in asymptomatic patients in rotation work conditions in the Arctic.

Material and methods. In the polar village of Yamburg (68° 21’ 40” northern latitude), 100 men and 80 women with grade 1, 2 hypertension and normotensive persons were examined on the basis of the Medical Unit of OOO Gazprom Dobycha Yamburg. All patients underwent echocardiography using generally accepted methods of imaging and data processing, according to European Society of Echocardiography guidelines. To calculate the probability of HFpEF, the H2FPEF score was used. The Bruce protocol treadmill test was performed. The SF-36 (Health Status Survey) questionnaire for assessment of life quality was used.

Results. Group 1 included 95 male and female patients with a low probability of HF (H2FPEF score — 0-1), group 2 — 85 patients of both sexes with an intermediate probability of HF (H2FPEF score — 2-5). Group 2 patients were older (p=0,038), worked longer on a shift (p=0,0143), and had higher ambulatory systolic (p=0,0001) and diastolic blood pressure (p=0,0013) with a higher body mass index (BMI) (p=0,0001). Based on the odds ratio (OR) analysis, the factor most strongly influencing the intermediate probability of HFpEF was BMI (OR=1,261, 95% confidence interval (CI): 1,140-1,393). SF-36 questionnaire revealed intergroup differences only on the role functioning scale (p=0,013) with lower values in group 2. In the logistic regression model, dyspnea during the treadmill test occupied a leading position as follows: OR=8,952; 95% CI: 3,454-15,197 (p<0,0001). The second place was taken by inotropic reserve value (OR=1,020; 95% CI: 1,006-1,035 (p=0,005), which was higher in group 2 and was regarded as one of the compensatory mechanisms for adapting to stress. In the group 2, echocardiography revealed significant differences in terms of left ventricular (LV) myocardial mass (p=0,0002), LV internal area (p=0,0002), isovolumic relaxation time (p=0,003), and ratio of transmitral diastolic flow rate to mean mitral annulus velocity (p=0,0001), which indirectly indicates the presence of LV diastolic dysfunction.

Conclusion. There are following factors associated with H2FPEF intermediate probability of HFpEF in asymptomatic patients on shift in the Arctic: BMI, length of shift, dyspnea and an increase in inotropic reserve during exercise due to a decrease in adaptive potential, impaired LV diastolic function. Initiating management strategies that target identified factors in patients with asymptomatic HF may slow symptomatic disease progression in shift workers in the Arctic region.

Targeting the Metabolic-Inflammatory Circuit in Heart Failure With Preserved Ejection Fraction

PURPOSE OF REVIEW

Heart failure with preserved ejection fraction (HFpEF) is a leading cause of morbidity and mortality. The current mechanistic paradigm supports a comorbidity-driven systemic proinflammatory state that evokes microvascular and myocardial dysfunction. Crucially, diabetes and obesity are frequently prevalent in HFpEF patients; as such, we review the involvement of a metabolic-inflammatory circuit in disease pathogenesis.

RECENT FINDINGS

Experimental models of diastolic dysfunction and genuine models of HFpEF have facilitated discovery of underlying drivers of HFpEF, where metabolic derangement and systemic inflammation appear to be central components of disease pathophysiology. Despite a shared phenotype among these models, molecular signatures differ depending on type and combination of comorbidities present. Inflammation, oxidative stress, hypertension, and metabolic derangements have been positioned as therapeutic targets to suppress the metabolic-inflammatory circuit in HFpEF. However, the stratification of unique patient phenogroups within the collective HFpEF subgroup argues for specific interventions for distinct phenogroups.

Additive Effects of Obesity on Myocardial Microcirculation and Left Ventricular Deformation in Essential Hypertension: A Contrast-Enhanced Cardiac Magnetic Resonance Imaging Study

Objective

The combination of hypertension and obesity is a major cause of cardiovascular risk, and microvascular changes and subclinical dysfunction should be considered to illustrate the underlying mechanisms and early identification, thereby developing targeted therapies. This study aims to explore the effect of obesity on myocardial microcirculation and left ventricular (LV) deformation in hypertensive patients by cardiac magnetic resonance (CMR).

Methods

This study comprised 101 hypertensive patients, including 54 subjects with a body mass index (BMI) of 18.5–24.9 kg/m² and 47 subjects with a BMI ≥25 kg/m², as well as 55 age- and sex-matched controls with a BMI of 18.5–24.9 kg/m². Myocardial perfusion indicators [upslope, time to maximum signal intensity (TTM), maximum signal intensity (Max SI)] and LV strains [radial, circumferential, and longitudinal global peak strain (PS), peak systolic strain rate (PSSR), and peak diastolic strain rate (PDSR)] were measured.

Results

Upslope was numerically increased in obese patients but statistically decreased in non-obese patients compared with controls. Longitudinal PS deteriorated significantly and gradually from controls to non-obese and obese hypertensive patients. Longitudinal PSSR and PDSR were significantly decreased in obese hypertensive patients compared with the other two groups. BMI was associated with upslope (β = −0.136, P < 0.001), Max SI (β = −0.922, P < 0.001), longitudinal PSSR (β = 0.018, P < 0.001), and PDSR (β = −0.024, P = 0.001). Myocardial perfusion was independently associated with longitudinal PSSR (TTM: β = 0.003, P = 0.017) and longitudinal PDSR (upslope: β = 0.067, P = 0.020) in hypertension.

Conclusion

Obesity had adverse effects on microvascular changes and subclinical LV dysfunction in hypertension, and BMI was independently associated with both myocardial perfusion and LV deformation. Impaired myocardial perfusion was independently associated with subclinical LV dysfunction in hypertension.

Left Atrial Strain as a Predictor of Left Ventricular Diastolic Dysfunction in Patients with Arterial Hypertension

Background and Objectives: There is emerging evidence of the usefulness of left atrial strain (LAS) in the assessment of diastolic dysfunction (DD). In this study we assess the sensitivity and specificity of LAS, to determine cut-off values and their association to DD with increased left atrial pressure (LAP) in patients with well-treated arterial hypertension. Materials and Methods: We performed a cross-sectional study on 180 subjects with well-treated arterial hypertension. All patients underwent transthoracic echocardiography. Patients were divided into two groups: a group without increased LAP and/or DD and a group with increased LAP DD. Results: In multivariate logistic regression, LAS proved to be the strongest statistically significant predictor of DD with increased LAP (OR 0.834, p < 0.0005), with AUC 0.885 and a set cut-off value of 24.27% with high sensitivity of 78.9% and specificity of 84.6%. The set cut-off for LAS > 24.27% was significantly highly prevalent in the group of DD with increased LAP 78.9% when compared to the group without increased LAP 15.4%, p < 0.0001. Conclusion: The findings of this study suggest that LAS could be a useful and highly sensitive and specific marker in the evaluation of DD. There is the potential for using LAS in everyday practice as a standard parameter in diastolic function assessment.

High-output Cardiac Failure: A Forgotten Phenotype in Clinical Practice

INTRODUCTION

The knowledge on High-Output Cardiac Failure (HOCF) has greatly improved in the last two decades. One of the advances was the identification of a new phenotype of HOCF, characterized by the absence of ventricular dilation, already associated with liver disease, Arteriovenous Fistulas (AVF), lung disease, myelodysplastic syndromes, and obesity. However, it has been noted that any aetiology can present with one of the two phenotypes, depending on the evolution.

OBJECTIVE

The study aims to describe, through an integrative review, the physiopathology and aetiologies of HOCF and to discuss phenotypes associated with this condition.

METHODS

Revisions, guidelines, case-controls, cohort studies and clinical studies were searched in MEDLINE and LILACS, using the connectives in the "cardiac output, high" database (MeSH Terms) OR "high cardiac output" (All Fields).

DISCUSSION

Two distinct phenotypes are currently described in the HOCF, regardless of the aetiology: 1) one with enlarged cardiac chambers; and 2) with normal heart chambers. The mechanisms related to HOCF are vasodilation, arteriovenous shunts that cause increased microvascular density, Reduced Systemic Vascular Resistance (RSVR), and high metabolism. These mechanisms lead to activation of the renin-angiotensin-aldosterone system, sodium and water retention, activation of neprilysin, of the sodium-glucose-2 transporter, which promote interstitial fibrosis, ventricular remodeling and a consequent increase in cardiac output >8L/min.

CONCLUSION

Many aetiologies of HOCF have been described, and some of them are potentially curable. Prompt recognition of this condition and proper treatment may lead to better outcomes.

Understanding Obesity-Related High Output Heart Failure and Its Implications

Morbid obesity remains most common cause of high output failure. The prevalence of the obesity is growing when two-thirds of American adults already are overweight or obese. Obesity is the risk factor for heart disease and eventually leads to heart failure. High output heart failure is common in obese patients and is characterized by high cardiac output, decreased systemic vascular resistance, and increased oxygen consumption. It often occurs in patients with chronic severe anemia, hyperthyroidism, pregnancy, arterial-venous fistulas, and liver disease. However, the pathogenesis of obesity-related high output heart failure is not fully understood. The clinical management of obesity-related high output heart failure follows conventional heart failure regimens due to lack of specific clinical recommendations. This article reviews the possible pathophysiological mechanisms and causes that contribute to obesity-related high output heart failure. This review also focuses on the implications for clinical practice and future research involved with omics technologies to explore possible molecular pathways associated with obesity-related high output heart failure.

Left ventricular dysfunction in heart failure with preserved ejection fraction-molecular mechanisms and impact on right ventricular function

The current classification of heart failure (HF) based on left ventricular (LV) ejection fraction (EF) identifies a large group of patients with preserved ejection fraction (HFpEF) with significant morbidity and mortality but without prognostic benefit from current HF therapy. Co-morbidities and conditions such as arterial hypertension, diabetes mellitus, chronic kidney disease, adiposity and aging shape the clinical phenotype and contribute to mortality. LV diastolic dysfunction and LV structural remodeling are hallmarks of HFpEF, and are linked to remodeling of the cardiomyocyte and extracellular matrix. Pulmonary hypertension (PH) and right ventricular dysfunction (RVD) are particularly common in HFpEF, and mortality is up to 10-fold higher in HFpEF patients with vs. without RV dysfunction. Here, we review alterations in cardiomyocyte function (i.e., ion homeostasis, sarcomere function and cellular metabolism) associated with diastolic dysfunction and summarize the main underlying cellular pathways. The contribution and interaction of systemic and regional upstream signaling such as chronic inflammation, neurohumoral activation, and NO-cGMP-related pathways are outlined in detail, and their diagnostic and therapeutic potential is discussed in the context of preclinical and clinical studies. In addition, we summarize prevalence and pathomechanisms of RV dysfunction in the context of HFpEF and discuss mechanisms connecting LV and RV dysfunction in HFpEF. Dissecting the molecular mechanisms of LV and RV dysfunction in HFpEF may provide a basis for an improved classification of HFpEF and for therapeutic approaches tailored to the molecular phenotype.

Matrix Metalloproteinases and Tissue Inhibitors of Metalloproteinases in Extracellular Matrix Remodeling during Left Ventricular Diastolic Dysfunction and Heart Failure with Preserved Ejection Fraction: A Systematic Review and Meta-Analysis

Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) are pivotal regulators of extracellular matrix (ECM) composition and could, due to their dynamic activity, function as prognostic tools for fibrosis and cardiac function in left ventricular diastolic dysfunction (LVDD) and heart failure with preserved ejection fraction (HFpEF). We conducted a systematic review on experimental animal models of LVDD and HFpEF published in MEDLINE or Embase. Twenty-three studies were included with a total of 36 comparisons that reported established LVDD, quantification of cardiac fibrosis and cardiac MMP or TIMP expression or activity. LVDD/HFpEF models were divided based on underlying pathology: hemodynamic overload (17 comparisons), metabolic alteration (16 comparisons) or ageing (3 comparisons). Meta-analysis showed that echocardiographic parameters were not consistently altered in LVDD/HFpEF with invasive hemodynamic measurements better representing LVDD. Increased myocardial fibrotic area indicated comparable characteristics between hemodynamic and metabolic models. Regarding MMPs and TIMPs; MMP2 and MMP9 activity and protein and TIMP1 protein levels were mainly enhanced in hemodynamic models. In most cases only mRNA was assessed and there were no correlations between cardiac tissue and plasma levels. Female gender, a known risk factor for LVDD and HFpEF, was underrepresented. Novel studies should detail relevant model characteristics and focus on MMP and TIMP protein expression and activity to identify predictive circulating markers in cardiac ECM remodeling.

The evolving systemic biomarker milieu in obese ZSF1 rat model of human cardiometabolic syndrome: Characterization of the model and cardioprotective effect of GDF15

Cardiometabolic syndrome has become a global health issue. Heart failure is a common comorbidity of cardiometabolic syndrome. Successful drug development to prevent cardiometabolic syndrome and associated comorbidities requires preclinical models predictive of human conditions. To characterize the heart failure component of cardiometabolic syndrome, cardiometabolic, metabolic, and renal biomarkers were evaluated in lean and obese ZSF1 19- to 32-week-old male rats. Histopathological assessment of kidneys and hearts was performed. Cardiac function, exercise capacity, and left ventricular gene expression were also analyzed. Obese ZSF1 rats exhibited multiple features of human cardiometabolic syndrome by pathological changes in systemic renal, metabolic, and cardiovascular disease circulating biomarkers. Hemodynamic assessment, echocardiography, and decreased exercise capacity confirmed heart failure with preserved ejection fraction. RNA-seq results demonstrated changes in left ventricular gene expression associated with fatty acid and branched chain amino acid metabolism, cardiomyopathy, cardiac hypertrophy, and heart failure. Twelve weeks of growth differentiation factor 15 (GDF15) treatment significantly decreased body weight, food intake, blood glucose, and triglycerides and improved exercise capacity in obese ZSF1 males. Systemic cardiovascular injury markers were significantly lower in GDF15-treated obese ZSF1 rats. Obese ZSF1 male rats represent a preclinical model for human cardiometabolic syndrome with established heart failure with preserved ejection fraction. GDF15 treatment mediated dietary response and demonstrated a cardioprotective effect in obese ZSF1 rats.

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.

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.

Extracellular Endothelial Cell-Derived Vesicles: Emerging Role in Cardiac and Vascular Remodeling in Heart Failure

Extracellular vesicles play a pivotal role in numerous physiological (immune response, cell-to-cell cooperation, angiogenesis) and pathological (reparation, inflammation, thrombosis/coagulation, atherosclerosis, endothelial dysfunction) processes. The development of heart failure is strongly associated with endothelial dysfunction, microvascular inflammation, alteration in tissue repair, and cardiac and vascular remodeling. It has been postulated that activated endothelial cell-derived vesicles are not just transfer forms of several active molecules (such as regulatory peptides, coagulation factors, growth factors, active molecules, hormones that are embedded onto angiogenesis, tissue reparation, proliferation, and even prevention from ischemia/hypoxia), but are instead involved in direct myocardial and vascular damage due to regulation of epigenetic responses of the tissue. These responses are controlled by several factors, such as micro-RNAs, that are transferred inside extracellular vesicles from mother cells to acceptor cells and are transductors of epigenetic signals. Finally, it is not a uniform opinion whether different phenotypes of heart failure are the result of altered cardiac and vascular reparation due to certain epigenetic responses, which are yielded by co-morbidities, such as diabetes mellitus and obesity. The aim of the review is to summarize knowledge regarding the role of various types of extracellular endothelial cell-derived vesicles in the regulation of cardiac and vascular remodeling in heart failure.

Limited synergy of obesity and hypertension, prevalent risk factors in onset and progression of heart failure with preserved ejection fraction

Obesity and hypertension are prevalent comorbidities in heart failure with preserved ejection fraction. To clarify if and how interaction between these comorbidities contributes to development of diastolic dysfunction, lean and obese ZSF1 rats were treated with deoxycorticosterone acetate implants and a high‐salt diet (DS) to induce severe hypertension, or with placebo. In addition to echocardiographic, metabolic and hemodynamic analyses, immunohistochemistry and RNAseq were performed on left ventricular tissue. Obesity negatively affected cardiac output, led to an elevated E/e’ ratio and mildly reduced ejection fraction. DS‐induced hypertension did not affect cardiac output and minimally elevated E/e’ ratio. Diastolic derangements in placebo‐treated obese rats developed in absence of inflammation and fibrosis, yet in presence of oxidative stress and hypertrophic remodelling. In contrast, hypertension triggered apoptosis, inflammation and fibrosis, with limited synergy of the comorbidities observed for inflammation and fibrosis. Transcriptional data suggested that these comorbidities exerted opposite effects on mitochondrial function. In placebo‐treated obese rats, genes involved in fatty acid metabolism were up‐regulated, whereas DS‐induced a down‐regulation of genes involved in oxidative phosphorylation. Overall, limited interaction was observed between these comorbidities in development of diastolic dysfunction. Importantly, differences in obesity‐ and hypertension‐induced cardiac remodelling emphasize the necessity for comorbidity‐specific phenotypical characterization.