Clinical Phenotypes of Heart Failure With Preserved Ejection Fraction to Select Preclinical Animal Models

In the heart and beyond: Mitochondrial dysfunction in heart failure with preserved ejection fraction (HFpEF)

Heart failure with preserved ejection fraction (HFpEF) is a major cardiovascular disorder with increasing prevalence and a limited range of targeted treatment options. While HFpEF can be derived from several different etiologies, much of the current growth in the disease is being driven by metabolic dysfunction (e.g. obesity, diabetes, hypertension). Deleterious changes in mitochondrial energy metabolism are a common feature of HFpEF, and may help to drive the progression of the disease. In this brief article we aim to review various aspects of cardiac mitochondrial dysfunction in HFpEF, discuss the emerging topic of HFpEF-driven mitochondrial dysfunction in tissues beyond the heart, and examine whether supporting mitochondrial function may be a therapeutic approach to arrest or reverse disease development.

Divergent cardiac and renal effects of miR-181c-5p inhibition in a rodent heart failure model

Aims

MiR-181c-5p overexpression associates with heart failure (HF) and cardiac damage, but the underlying pathophysiology remains unclear. This study investigated the effect of miR-181c-5p inhibition on cardiac function and fibrosis in a rodent model of diastolic dysfunction, and evaluated additional effects on kidney as relevant comorbid organ.

Methods and results

Diastolic dysfunction was induced in male C57/BL6J mice (n = 20) by combining high-fat diet, L-NG-nitroarginine methyl ester, and angiotensin II administration, and was compared to sham controls (n = 18). Mice were randomized to subcutaneous miR-181c-5p antagomiR (INH) or scrambled antagomiR injections (40 mg/kg/week). HF mice demonstrated diastolic dysfunction and increased fibrosis, which was attenuated by INH treatment. Remarkably, HF + INH animals had a threefold higher mortality rate (60%) compared to HF controls (20%). Histological examination revealed increased glomerular damage in all INH treated mice, and signs of thrombotic microangiopathy (TMA) in mice who died prematurely. Quantitative polymerase chain reaction demonstrated a miR-181c-5p-related downregulation of cardiac but not renal Tgfbr1 in HF + INH mice, while INH treatment reduced renal but not cardiac Vegfa expression in all mice.

Conclusion

This study demonstrates cardiac anti-fibrotic effects of miR-181c-5p inhibition in a rodent HF model through targeting of Tgfbr1 in the heart. Despite improved diastolic function, HF + INH mice had higher mortality due to increased predisposition for TMA, increased renal fibrosis and glomerular damage, associated with Vegfa downregulation in kidneys.

A roadmap for therapeutic discovery in pulmonary hypertension associated with left heart failure. A scientific statement of the Heart Failure Association (HFA) of the ESC and the ESC Working Group on Pulmonary Circulation & Right Ventricular Function

Pulmonary hypertension (PH) associated with left heart failure (LHF) (PH-LHF) is one of the most common causes of PH. It directly contributes to symptoms and reduced functional capacity and negatively affects right heart function, ultimately leading to a poor prognosis. There are no specific treatments for PH-LHF, despite the high number of drugs tested so far. This scientific document addresses the main knowledge gaps in PH-LHF with emphasis on pathophysiology and clinical trials. Key identified issues include better understanding of the role of pulmonary venous versus arteriolar remodelling, multidimensional phenotyping to recognize patient subgroups positioned to respond to different therapies, and conduct of rigorous pre-clinical studies combining small and large animal models. Advancements in these areas are expected to better inform the design of clinical trials and extend treatment options beyond those effective in pulmonary arterial hypertension. Enrichment strategies, endpoint assessments, and thorough haemodynamic studies, both at rest and during exercise, are proposed to play primary roles to optimize early-stage development of candidate therapies for PH-LHF.

Cardiac reverse remodeling in a mouse model with many phenotypical features of heart failure with preserved ejection fraction: effects of modifying lifestyle

Multiple factors cause heart failure with preserved ejection fraction (HFpEF) and involve various systems. HFpEF prevalence is rapidly rising, and its prognosis remains poor after the first hospitalization. Adopting a more active lifestyle has been shown to provide beneficial clinical outcomes for patients with HFpEF. Using a two-hit HfpEF murine model, we studied cardiac reverse remodeling (RR) after stopping the causing stress and introducing voluntary exercise (VE). We checked in 2-mo-old male and female C57Bl6/J mice the heart's response to angiotensin II (ANG II; 1.5 mg/kg/day for 28 days) fed or not with a high-fat diet (HFD). Then, ANG II and/or the HFD were stopped, and VE was started for an additional 4 wk. ANG II and ANG II + HFD (metabolic-hypertensive stress, MHS) caused cardiac hypertrophy (CH) and myocardial fibrosis, left ventricular (LV) concentric remodeling, atrial enlargement, and reduced exercise capacity. HFD alone induced CH and LV concentric remodeling in female mice only. CH and LV concentric remodeling were reversed 4 wk after stopping ANG II, starting VE, and a low-fat diet. Left atrial enlargement and exercise capacity were improved but differed from controls. We performed bulk LV RNA sequencing and observed that MHS upregulated 58% of the differentially expressed genes (DEGs) compared with controls. In the RR group, compared with MHS animals, 60% of the DEGs were downregulated. In an HfpEF mouse model, we show that correcting hypertension, diet, and introducing exercise can lead to extensive cardiac reverse remodeling.NEW & NOTEWORTHY Using a two-hit murine model of heart failure with preserved ejection fraction (HfpEF), combining elevated blood pressure, obesity, and exercise intolerance in male and female animals, we showed that correction of hypertension, normalization of the diet, and introduction of voluntary exercise could help reverse the remodeling of the left ventricle and double exercise capacity. We also identify genes that escape normalization after myocardial recovery and differences between males' and females' responses to stress and recovery.

Inhibiting the MAPK pathway improves heart failure with preserved ejection fraction induced by salt-sensitive hypertension

Heart failure (HF) preserved ejection fraction (HFpEF) accounts for almost 50% of HF, and hypertension is one of the pathogenies. The MAPK signaling pathway is closely linked to heart failure and hypertension; however, its function in HEpEF resulting from salt-sensitive hypertension is not well understood. In this work, a salt-sensitive hypertension-induced HEpEF model was established based on deoxycorticosterone acetate-salt (DOCA-salt) hypertension mice. The impact of the MAPK inhibitor (Doramapimod) on HEpEF induced by salt-sensitive hypertension was assessed through various measures, such as blood pressure, transthoracic echocardiography, running distance, and histological analysis, to determine its therapeutic effectiveness on cardiac function. In addition, the effects of high salt on myogenic cells were also evaluated in vitro using qRTPCR. The LV ejection fractions (LVEF) in DOCA-salt hypertension mice were over 50%, indicating that the salt-sensitive hypertension-induced HFpEF model was successful. RNA-seq revealed that the MAPK signaling pathway was upregulated in the HFpEF model compared with the normal mice, accompanied by hypertension, impaired running distance, restricted cardiac function, increased cross-sectional and fibrosis area, and upregulation of heart failure biomarkers, including GAL-3, LDHA and BNP. The application of Doramapimod could improve blood pressure, cardiomyocyte hypertrophy, and myocardial fibrosis, as well as decrease the aforementioned heart failure biomarkers. The qRTPCR results showed similar findings to these observations. Our findings suggest that the use of a MAPK inhibitor (Doramapimod) could be a potential treatment for salt-sensitive hypertension-induced HFpEF.

A rat model of metabolic syndrome-related heart failure with preserved ejection fraction phenotype: pathological alterations and possible molecular mechanisms

Background

Heart failure with preserved ejection fraction (HFpEF) represents a syndrome involving multiple pathophysiologic disorders and clinical phenotypes. This complexity makes it challenging to develop a comprehensive preclinical model, which presents an obstacle to elucidating disease mechanisms and developing new drugs. Metabolic syndrome (MetS) is a major phenotype of HFpEF. Thus, we produced a rat model of the MetS-related HFpEF phenotype and explored the molecular mechanisms underpinning the observed pathological changes.

Methods

A rat model of the MetS-related HFpEF phenotype was created by feeding spontaneously hypertensive rats a high-fat-salt-sugar diet and administering streptozotocin solution intraperitoneally. Subsequently, pathological changes in the rat heart and their possible molecular mechanisms were explored.

Results

The HFpEF rats demonstrated primary features of MetS, such as hypertension, hyperglycemia, hyperlipidemia, insulin resistance, and cardiac anomalies, such as left ventricular (LV) remodeling and diastolic impairment, and left atrial dilation. Additionally, inflammation, myocardial hypertrophy, and fibrosis were observed in LV myocardial tissue, which may be associated with diverse cellular and molecular signaling cascades. First, the inflammatory response might be related to the overexpression of inflammatory regulators (growth differentiation factor 15 (GDF-15), intercellular adhesion molecule-1 (ICAM-1), and vascular endothelial cell adhesion molecule-1 (VCAM-1)). Secondly, phosphorylated glycogen synthase kinase 3β (GSK-3β) may stimulate cardiac hypertrophy, which was regulated by activated -RAC-alpha serine/threonine-protein kinase (AKT). Finally, the transforming growth factor-β1 (TGF-β1)/Smads pathway might regulate collagen production and fibroblast activation, promoting myocardial fibrosis.

Conclusion

The HFpEF rat replicates the pathology and clinical presentation of human HFpEF with MetS and may be a reliable preclinical model that helps elucidate HFpEF pathogenesis and develop effective treatment strategies.

Three-vessel coronary infusion of cardiosphere-derived cells for the treatment of heart failure with preserved ejection fraction in a pre-clinical pig model

Heart failure with preserved ejection fraction (HFpEF) is a major public health concern. Its outcome is poor and, as of today, barely any treatments have been able to decrease its morbidity or mortality. Cardiosphere-derived cells (CDCs) are heart cell products with anti-fibrotic, anti-inflammatory and angiogenic properties. Here, we tested the efficacy of CDCs in improving left ventricular (LV) structure and function in pigs with HFpEF. Fourteen chronically instrumented pigs received continuous angiotensin II infusion for 5 weeks. LV function was investigated through hemodynamic measurements and echocardiography at baseline, after 3 weeks of angiotensin II infusion before three-vessel intra-coronary CDC (n = 6) or placebo (n = 8) administration and 2 weeks after treatment (i.e., at completion of the protocol). As expected, arterial pressure was significantly and similarly increased in both groups. This was accompanied by LV hypertrophy that was not affected by CDCs. LV systolic function remained similarly preserved during the whole protocol in both groups. In contrast, LV diastolic function was impaired (increases in Tau, LV end-diastolic pressure as well as E/A, E/E'septal and E/E'lateral ratios) but CDC treatment significantly improved all of these parameters. The beneficial effect of CDCs on LV diastolic function was not explained by reduced LV hypertrophy or increased arteriolar density; however, interstitial fibrosis was markedly reduced. Three-vessel intra-coronary administration of CDCs improves LV diastolic function and reduces LV fibrosis in this hypertensive model of HFpEF.

Trends in worldwide research on cardiac fibrosis over the period 1989-2022: a bibliometric study

Background

Cardiac fibrosis is a hallmark of various end-stage cardiovascular diseases (CVDs) and a potent contributor to adverse cardiovascular events. During the past decades, extensive publications on this topic have emerged worldwide, while a bibliometric analysis of the current status and research trends is still lacking.

Methods

We retrieved relevant 13,446 articles on cardiac fibrosis published between 1989 and 2022 from the Web of Science Core Collection (WoSCC). Bibliometrix was used for science mapping of the literature, while VOSviewer and CiteSpace were applied to visualize co-authorship, co-citation, co-occurrence, and bibliographic coupling networks.

Results

We identified four major research trends: (1) pathophysiological mechanisms; (2) treatment strategies; (3) cardiac fibrosis and related CVDs; (4) early diagnostic methods. The most recent and important research themes such as left ventricular dysfunction, transgenic mice, and matrix metalloproteinase were generated by burst analysis of keywords. The reference with the most citations was a contemporary review summarizing the role of cardiac fibroblasts and fibrogenic molecules in promoting fibrogenesis following myocardial injury. The top 3 most influential countries were the United States, China, and Germany, while the most cited institution was Shanghai Jiao Tong University, followed by Nanjing Medical University and Capital Medical University.

Conclusions

The number and impact of global publications on cardiac fibrosis has expanded rapidly over the past 30 years. These results are in favor of paving the way for future research on the pathogenesis, diagnosis, and treatment of cardiac fibrosis.

Personalized Management for Heart Failure with Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is a heterogeneous clinical syndrome with multiple underlying mechanisms and comorbidities that leads to a variety of clinical phenotypes. The identification and characterization of these phenotypes are essential for better understanding the precise pathophysiology of HFpEF, identifying appropriate treatment strategies, and improving patient outcomes. Despite accumulating data showing the potentiality of artificial intelligence (AI)-based phenotyping using clinical, biomarker, and imaging information from multiple dimensions in HFpEF management, contemporary guidelines and consensus do not incorporate these in daily practice. In the future, further studies are required to authenticate and substantiate these findings in order to establish a more standardized approach for clinical implementation.

Evaluation of large animal models for preclinical studies of heart failure with preserved ejection fraction using clinical score systems

Heart failure with preserved ejection fraction (HFpEF) is characterized by a complex, heterogeneous spectrum of pathologic features combined with average left ventricular volume and diastolic dysfunction. HFpEF is a significant public health problem associated with high morbidity and mortality rates. Currently, effective treatments for HFpEF represent the greatest unmet need in cardiovascular medicine. A lack of an efficient preclinical model has hampered the development of new devices and medications for HFpEF. Because large animal models have similar physiologic traits as humans and appropriate organ sizes, they are the best option for limiting practical constraints. HFpEF is a highly integrated, multiorgan, systemic disorder requiring a multipronged investigative approach. Here, we review the large animal models of HFpEF reported to date and describe the methods that have been used to create HFpEF, including surgery-induced pressure overloading, medicine-induced pressure overloading, and diet-induced metabolic syndrome. In addition, for the first time to our knowledge, we use two established clinical HFpEF algorithms (HFA-PEFF and H2FPEF scores) to evaluate the currently available large animal models. We also discuss new technologies, such as continuous remote pressure monitors and inflatable aortic cuffs, as well as how the models could be improved. Based on current progress and our own experience, we believe an efficient large animal model of HFpEF should simultaneously encompass multiple pathophysiologic factors, along with multiorgan dysfunction. This could be fully evaluated through available methods (imaging, blood work). Although many models have been studied, only a few studies completely meet clinical score standards. Therefore, it is critical to address the deficiencies of each model and incorporate novel techniques to establish a more reliable model, which will help facilitate the understanding of HFpEF mechanisms and the development of a treatment.

Pathological mechanism of heart failure with preserved ejection fraction in rats based on iTRAQ technology

Objective

Heart failure with preserved ejection fraction (HFpEF) is a public health problem worldwide. Treatments for the patients with HFpEF are not satisfactory because there is no unified understanding of the pathological mechanism of HFpEF. This study aims at investigating the potential pathological mechanism for the effective diagnosis and treatment of HFpEF.

Methods

Ten adult male Dahl salt sensitive rats (180-200 g) were divided into control and model groups. The rats in model group were fed with high salt diet (8% NaCl) to induce HFpEF for this comparative study. Behavioral changes, biochemical parameters, and histopathological changes of the rats were detected. iTRAQ technology combined with bioinformatics analysis was employed to study the differentially expressed proteins (DEPs) and their enrichment in signaling pathways.

Results

Echocardiography detection showed decreased LVEF, indicating impaired cardiac function (P < 0.01), increased LVPWd, indicating ventricular wall hypertrophy (P < 0.05), prolonged duration of IVRT and decreased E/A ratio, indicating diastolic dysfunction (P < 0.05) of the rats in model group. 563 DEPs were identified in the rats of both groups, with 243 up-regulated and 320 down-regulated. The expression of PPAR signaling pathway in the rats of model group was down-regulated, with PPARα most significantly decreased (91.2%) (P < 0.01), PPARγ obviously decreased (63.60%) (P < 0.05), and PPARβ/δ decreased (45.33%) (P < 0.05). The DEPs enriched in PPAR signaling pathway were mainly related to such biological processes as fatty acid beta-oxidation, such cellular components as peroxisome, and such molecular functions as lipid binding.

Conclusions

NaCl high salt diet is one of the factors to increase the incidence of HFpEF in rats. PPARα, PPARγ and PPAR β/δ might be the targets of HFpEF. The findings may provide a theoretical basis for the treatment of HFpEF in clinical practice.

Diastolic dysfunction and sex-specific progression to HFpEF: current gaps in knowledge and future directions

Diastolic dysfunction of the left ventricle (LVDD) is equally common in elderly women and men. LVDD is a condition that can remain latent for a long time but is also held responsible for elevated left ventricular filling pressures and high pulmonary pressures that may result in (exercise-induced) shortness of breath. This symptom is the hallmark of heart failure with preserved ejection fraction (HFpEF) which is predominantly found in women as compared to men within the HF spectrum. Given the mechanistic role of LVDD in the development of HFpEF, we review risk factors and mechanisms that may be responsible for this sex-specific progression of LVDD towards HFpEF from an epidemiological point-of-view and propose future research directions.