Development Of Heart Failure With Preserved Ejection Fraction Research Articles

Roles of cMyBP-C phosphorylation on cardiac contractile dysfunction in db/db mice

Type 2 diabetes mellitus (T2DM) is a metabolic disease and comorbidity associated with several conditions, including cardiac dysfunction leading to heart failure with preserved ejection fraction (HFpEF), in turn resulting in T2DM-induced cardiomyopathy (T2DM-CM). However, the molecular mechanisms underlying the development of T2DM-CM are poorly understood. It is hypothesized that molecular alterations in myopathic genes induced by diabetes promote the development of HFpEF, whereas cardiac myosin inhibitors can rescue the resultant T2DM-mediated cardiomyopathy. To test this hypothesis, a Leptin receptor-deficient db/db homozygous (Lepr db/db) mouse model was used to define the pathogenesis of T2DM-CM. Echocardiographic studies at 4 and 6 months revealed that Lepr db/db hearts started developing cardiac dysfunction by four months, and left ventricular hypertrophy with diastolic dysfunction was evident at 6 months. RNA-seq data analysis, followed by functional enrichment, revealed the differential regulation of genes related to cardiac dysfunction in Lepr db/db heart tissues. Strikingly, the level of cardiac myosin binding protein-C phosphorylation was significantly increased in Lepr db/db mouse hearts. Finally, using isolated skinned papillary muscles and freshly isolated cardiomyocytes, CAMZYOS® (mavacamten, MYK-461), a prescription heart medicine used for symptomatic obstructive hypertrophic cardiomyopathy treatment, was tested for its ability to rescue T2DM-CM. Compared with controls, MYK-461 significantly reduced force generation in papillary muscle fibers and cardiomyocyte contractility in the db/db group. This line of evidence shows that 1) T2DM-CM is associated with hyperphosphorylation of cardiac myosin binding protein-C and 2) MYK-461 significantly lessened disease progression in vitro, suggesting its promise as a treatment for HFpEF.

Incidence and predictors of heart failure with reduced and preserved ejection fraction after ST-elevation myocardial infarction in the contemporary era of early percutaneous coronary intervention.

The development and incidence of de-novo heart failure after ST-elevation myocardial infarction (STEMI) in the contemporary era of rapid reperfusion are largely unknown. We aimed to establish the incidence of post-STEMI heart failure, stratified by left ventricular ejection fraction (LVEF) and to find predictors for its occurrence. Furthermore, we investigated the course of left ventricular systolic and diastolic function after STEMI. A total of 1172 all-comer STEMI patients from the CardioLines Biobank were included. Patients were predominantly male (74.5%) and 64 ± 12 years of age. During a median follow-up of 3.7 years (2.0, 5.5) we found a total incidence of post-STEMI heart failure of 10.9%, of which 52.1% heart failure with reduced ejection fraction (HFrEF), 29.4% heart failure with mildly reduced ejection fraction and 18.5% heart failure with preserved ejection fraction (HFpEF). Independent predictors for the development of HFrEF were male sex (β = 0.97, p = 0.009), lung crepitations (β = 1.09, p = 0.001), potassium level (mmol/L, β = 0.43, p = 0.012), neutrophil count (109/L, β = 0.09, p = 0.001) and a reduced LVEF (β = 1.91, p < 0.001) at baseline. Independent predictors for the development of HFpEF were female sex (β = 0.99, p = 0.029), pre-existing kidney failure (β = 1.95, p = 0.003) and greater left atrial volume index (β = 0.04, p = 0.033) at baseline. Follow-up echocardiography (median follow-up 20 months) showed an improvement in LVEF (p < 0.001), whereas changes in diastolic function parameters showed both improvement and deterioration. In the current era of early STEMI reperfusion, still one in 10 patients develops heart failure, with approximately half of the patients with a reduced and half with a mildly reduced or normal LVEF. Predictors for the development of HFrEF were different from HFpEF.

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

The molecular signatures in epicardial adipose tissue (EAT) that contribute to the pathogenesis of heart failure with preserved ejection fraction (HFpEF) are poorly characterized. In this study, we sought to elucidate molecular signatures including genetic transcripts and long non-coding RNAs (lncRNAs) in EAT that might modulate HFpEF development. RNA sequencing (RNA-seq) was performed to identify differentially expressed lncRNAs and mRNAs in EAT samples from patients with HFpEF (n=5) and without HF (control, n=5) who underwent coronary artery bypass grafting. The sequencing results were validated using quantitative real-time PCR (qRT-PCR). Bioinformatics analysis (Gene Ontology and Kyoto Encyclopedia of Genes and Genomes) of differentially expressed RNAs was performed to predict enriched functions. HFpEF patients had higher EAT thickness and NT-proBNP levels than the control group. A total of 64471 transcripts were detected including 35395 protein-coding sequences, corresponding to 16854 genes in EAT. RNA-seq identified a total of 741 dysregulated mRNA transcripts (394 up-regulated and 347 down-regulated) and 334 differentially expressed lncRNA transcripts (222 up-regulated and 112 down-regulated) in the HFpEF group compared with the control group (P<0.05). qRT-PCR analysis confirmed that two lncRNAs ENST00000561775 (P=0.0194) and ENST00000519093 (P=0.027) and an mRNA POSTN (P=0.003) were differentially expressed. Functional enrichment analysis of the differentially expressed mRNAs suggested their potential roles in immune response involving cytokine interaction and chemokine signalling. We are the first group to report on the lncRNA and mRNA landscape in EAT in HFpEF patients. Our study suggests the possible role of lncRNAs in EAT.

Phenotypic differences in Obese Patients with Heart Failure with Preserved Ejection Fraction (HFpEF) - A Mini Review

The incidence of heart failure with preserved ejection fraction (HFpEF) continues to rise, and obesity continues to be a predominant comorbid condition affecting patients with HFpEF. Recent research sheds light on the important pathophysiologic role that obesity plays in the development of HFpEF, with many areas of opportunity existing for future developments in understanding the etiology and management of the disease. Crucial in these pathophysiologic developments are studies that clearly characterize the obesity phenotype in HFpEF and compare it to presentations of HFpEF in patients without obesity. This paper reviews the existing literature on the obesity phenotype within HFpEF and discusses some of the prevailing ideas behind the pathophysiologic interplay between the conditions, as well as the existing treatments demonstrating improved outcomes in HFpEF.

Preload dependence in an animal model of mild heart failure with preserved ejection fraction (HFpEF).

Heart Failure with preserved Ejection Fraction (HFpEF) is characterized by diastolic dysfunction and reduced cardiac output, but its pathophysiology remains poorly understood. Animal models of HFpEF are challenging due to difficulties in assessing the degree of heart failure in small animals. This study aimed at inducing HFpEF in a mouse model to probe preload-dependency. Increased body mass and arterial hypertension were induced in mice using a Western diet and NO synthase inhibition. Preload dependence was tested exvivo. Mice with obesity and hypertension exhibited reduced cardiac output, indicating a failing heart. Increased left ventricular filling pressure during diastole suggested reduced compliance. Notably, the ejection fraction was preserved, suggesting the development of HFpEF. Spontaneous physical activity at night was reduced in HFpEF mice, indicating exercise intolerance; however, the cardiac connective tissue content was comparable between HFpEF and control mice. The HFpEF mice showed increased vulnerability to reduced preload exvivo, indicating that elevated left ventricular filling pressure compensated for the rigid left ventricle, preventing a critical decrease in cardiac output. This animal model successfully developed mild HFpEF with a reduced pump function that was dependent on a high preload. A model of mild HFpEF may serve as a valuable tool for studying disease progression and interventions aimed at delaying or reversing symptom advancement, considering the slow development of HFpEF in patients.

Novel insights into myocardial injury, diastolic pathology, and in-hospital mortality: the impact of H2FPEF score in COVID-19 patients

Aims: H2FPEF score is a reliable tool for diagnosing heart failure with preserved ejection fraction (HFpEF) linked to diastolic dysfunction. Our objective was to explore the correlation between H2FPEF score and in-hospital mortality, as well as parameters previously identified in association with COVID-19, among hospitalized COVID-19 patients. Methods: This prospective, single-center observational study included 205 consecutive COVID-19 hospitalized patients. Data regarding patients' clinical status, comorbidities, and drug therapy were extracted from medical histories and records. Afterward, we calculated H2FPEF score for each patient and subsequently grouped them based on the following score categories: low (0-1), medium (2-5), and high (6-9). Logistic regression and Kaplan-Meier survival curve analyses were conducted to assess in-hospital mortality and the presence of an intermediate-to-high H2FPEF score. Results: Death occurred in 46 (22.4%) patients. 79 participants (38.5%) fell into the low-risk category (0-1 points), 108 (52.7%) were classified as intermediate-risk (2-5 points), and the remaining 18 (8.8%) were in the high-risk category (6-9 points). Age, heart rate, body mass index, and co-morbidities exhibited a rising trend with increasing H2FPEF scores (p&amp;lt;0.05 for all). Moreover, an escalation in the H2FPEF category correlated with deteriorated echocardiographic parameters. Multivariable logistic regression analysis revealed that heart rate per minute (OR=1.048, p=0.022), H2FPEF score (OR=1.396, p=0.018), and current smoker (OR=4.569, p=0.050) were independent determinants of in-hospital mortality. ROC curve indicated that the H2FPEF score, with a threshold of ≥2, exhibited good discriminative capacity, demonstrating 80.4% sensitivity and 69.2% specificity (AUC=0.777, p&amp;lt;0.001). The pairwise comparison of ROC curves analysis demonstrated that troponin (AUC=0.819) exhibited better discriminative abilities than both D-dimer (AUC=0.737, p=0.029) and hemoglobin (AUC=0.691, p=0.007) in determining an intermediate-to-high H2FPEF score. Conclusion: COVID-19, recognized for its association with myocardial damage, could emerge as a significant risk factor for the onset of HFpEF. H2FPEF score presents as a straightforward tool for rapid risk assessment upon hospitalization, potentially aiding in the evaluation of the risk for HFpEF development. Its utilization may facilitate early intervention, thereby contributing to a reduction in poor outcomes.

Unveiling the vulnerability of C57BL/6J female mice to HFpEF and its related complications

IntroductionThe impact of female biological sex on the development of heart failure with preserved ejection fraction (HFpEF) and its associated kidney disease and vascular endothelial dysfunction is still controversial. Whether females are protected from HFpEF and associated complications is not well established. Previous studies report conflicting prevalence between genders. We hypothesize that female mice are unprotected from HFpEF and its associated kidney disease and vascular endothelial dysfunction. MethodsEight-week-old female mice were divided into four groups: control groups receiving a standard diet and water for either 5 or 16 weeks, and HFpEF groups fed a high-fat diet (HFD, Rodent Diet With 60 kcal% Fat) and N[w]-nitro-l-arginine methyl ester (L-NAME - 0.5 g/L) in the drinking water for 5 or 16 weeks. Various measurements and assessments were performed, including echocardiography, metabolic and hypertensive evaluations, markers of heart and kidney injury, and assessment of vascular endothelial function. ResultsFemale mice with HFD and L-NAME developed HFpEF at 5 weeks, evidenced by increased E/E' ratio, reduced cardiac index, left ventricular mass, and unchanged ejection fraction. After 16 weeks, HFpEF worsened. Metabolic disorders, hypertension, lung wet/kidney weight increase, exercise intolerance, and cardiac/renal injury markers were observed. Vascular endothelial dysfunction was associated with ER stress and fibrosis induction. ConclusionsWe found that female mice are susceptible to the development of HFpEF and its associated kidney disease and vascular endothelial dysfunction. Our data support the concept that the female sex does not protect from HFpEF and its associated kidney disease and vascular endothelial dysfunction when disease risk factors are present.

Impact of ovary-intact menopause in a mouse model of heart failure with preserved ejection fraction.

Heart failure with preserved ejection fraction (HFpEF) afflicts over half of all patients with heart failure and is a debilitating and fatal syndrome affecting postmenopausal women more than any other demographic. This bias toward older females calls into question the significance of menopause in the development of HFpEF, but this question has not been probed in detail. In this study, we report the first investigation into the impact of ovary-intact menopause in the context of HFpEF. To replicate the human condition as faithfully as possible, vinylcyclohexene dioxide (VCD) was used to accelerate ovarian failure (AOF) in female mice while leaving the ovaries intact. HFpEF was established with a mouse model that involves two stressors typical in humans: a high-fat diet and hypertension induced from the nitric oxide synthase inhibitor NG-nitro-l-arginine methyl ester (l-NAME). In young female mice, AOF or HFpEF-associated stressors independently induced abnormal myocardial strain indicative of early subclinical systolic and diastolic cardiac dysfunction. HFpEF but not AOF was associated with elevations in systolic blood pressure. Increased myocyte size and reduced myocardial microvascular density were not observed in any group. Also, a broad panel of measurements that included echocardiography, invasive pressure measurements, histology, and serum hormones revealed no interaction between AOF and HFpEF. Interestingly, AOF did evoke a higher density of infiltrating cardiac immune cells in both healthy and HFpEF mice, suggestive of proinflammatory effects. In contrast to young mice, middle-aged "old" mice did not exhibit cardiac dysfunction from estrogen deprivation alone or from HFpEF-related stressors.NEW & NOTEWORTHY This is the first preclinical study to examine the impact of ovary-intact menopause [accelerated ovarian failure (AOF)] on HFpEF. Echocardiography of young female mice revealed early evidence of diastolic and systolic cardiac dysfunction apparent only on strain imaging in HFpEF only, AOF only, or the combination. Surprisingly, AOF did not exacerbate the HFpEF phenotype. Results in middle-aged "old" females also showed no interaction between HFpEF and AOF and, importantly, no cardiovascular impact from HFpEF or AOF.

Pericyte loss initiates microvascular dysfunction in the development of diastolic dysfunction.

Microvascular dysfunction has been proposed to drive heart failure with preserved ejection fraction (HFpEF), but the initiating molecular and cellular events are largely unknown. Our objective was to determine when microvascular alterations in HFpEF begin, how they contribute to disease progression, and how pericyte dysfunction plays a role herein. Microvascular dysfunction, characterized by inflammatory activation, loss of junctional barrier function, and altered pericyte-endothelial crosstalk, was assessed with respect to the development of cardiac dysfunction, in the Zucker fatty and spontaneously hypertensive (ZSF1) obese rat model of HFpEF at three time points: 6, 14, and 21 weeks of age. Pericyte loss was the earliest and strongest microvascular change, occurring before prominent echocardiographic signs of diastolic dysfunction were present. Pericytes were shown to be less proliferative and had a disrupted morphology at 14 weeks in the obese ZSF1 animals, who also exhibited an increased capillary luminal diameter and disrupted endothelial junctions. Microvascular dysfunction was also studied in a mouse model of chronic reduction in capillary pericyte coverage (PDGF-Bret/ret), which spontaneously developed many aspects of diastolic dysfunction. Pericytes exposed to oxidative stress in vitro showed downregulation of cell cycle-associated pathways and induced a pro-inflammatory state in endothelial cells upon co-culture. We propose pericytes are important for maintaining endothelial cell function, where loss of pericytes enhances the reactivity of endothelial cells to inflammatory signals and promotes microvascular dysfunction, thereby accelerating the development of HFpEF.

Obesity Is a Major Determinant of Impaired Cardiac Energy Metabolism in Heart Failure with Preserved Ejection Fraction.

Heart failure with preserved ejection fraction (HFpEF) is a major health problem with limited treatment options. Although optimizing cardiac energy metabolism is a potential approach to treating heart failure, it is poorly understood what alterations in cardiac energy metabolism actually occur in HFpEF. To determine this, we used mice in which HFpEF was induced using an obesity and hypertension HFpEF protocol for 10 weeks. Next, carvedilol, a third-generation β-blocker and a biased agonist that exhibits agonist-like effects through β arrestins by activating extracellular signal-regulated kinase, was used to decrease one of these parameters, namely hypertension. Heart function was evaluated by invasive pressure-volume loops and echocardiography as well as by ex vivo working heart perfusions. Glycolysis and oxidation rates of glucose, fatty acids, and ketones were measured in the isolated working hearts. The development of HFpEF was associated with a dramatic decrease in cardiac glucose oxidation rates, with a parallel increase in palmitate oxidation rates. Carvedilol treatment decreased the development of HFpEF but had no major effect on cardiac energy substrate metabolism. Carvedilol treatment did increase the expression of cardiac β arrestin 2 and proteins involved in mitochondrial biogenesis. Decreasing bodyweight in obese HFpEF mice increased glucose oxidation and improved heart function. This suggests that the dramatic energy metabolic changes in HFpEF mice hearts are primarily due to the obesity component of the HFpEF model. SIGNIFICANCE STATEMENT: Metabolic inflexibility occurs in heart failure with preserved ejection fraction (HFpEF) mice hearts. Lowering blood pressure improves heart function in HFpEF mice with no major effect on energy metabolism. Between hypertension and obesity, the latter appears to have the major role in HFpEF cardiac energetic changes. Carvedilol increases mitochondrial biogenesis and overall energy expenditure in HFpEF hearts.

Peripheral Blood MicroRNA-21 as a Predictive Biomarker for Heart Failure With Preserved Ejection Fraction in Old Hypertensives.

Heart failure with preserved ejection fraction (HFpEF) is a major health issue with high morbidity and mortality. The epidemiology and the factors that cause HFpEF have not been fully clarified, while accurate predictive biomarkers are lacking. Our aim was to determine whether levels of microRNA-21 (miR-21) in peripheral blood monocytes, which play a critical role in many pathophysiological pathways of hypertensive heart disease, can predict the occurrence of HFpEF in older hypertensives, as well as the associated mortality and morbidity. We enrolled 151 elderly patients >60 years old with essential hypertension but without HF at baseline. miRs expression levels in peripheral blood mononuclear cells had been quantified by real-time reverse transcription polymerase chain reaction. During a median follow-up of 8.2 years, 56 patients (37%) had an event. Levels of miR-21 in peripheral mononuclear blood cells proved to be significantly associated with the occurrence of HFpEF. More specifically, the median HFpEF-free period was 110 months for those with miR-21 >2.1 and 114 months for those with miR-21 <2.1. In addition, multivariate analysis showed that miR-21 (hazard ratio 11.14), followed by hemoglobin (Hg) (hazard ratio 0.56 for Hg >13.6 g/dl, a 45% risk reduction), were independent and the most significant predictors of HFpEF events. miR-21 levels in peripheral blood monocytes are associated with the development of future HFpEF. Our findings may alter the risk models of HFpEF and support the rationale for further research into the modulation of miRs as biomarkers and treatment targets for HFpEF.

Insights into the Interaction of Heart Failure with Preserved Ejection Fraction and Sleep-Disordered Breathing.

Heart failure with preserved ejection fraction (HFpEF) is emerging as a widespread disease with global socioeconomic impact. Patients with HFpEF show a dramatically increased morbidity and mortality, and, unfortunately, specific treatment options are limited. This is due to the various etiologies that promote HFpEF development. Indeed, cluster analyses with common HFpEF comorbidities revealed the existence of several HFpEF phenotypes. One especially frequent, yet underappreciated, comorbidity is sleep-disordered breathing (SDB), which is closely intertwined with the development and progression of the "obese HFpEF phenotype". The following review article aims to provide an overview of the common HFpEF etiologies and phenotypes, especially in the context of SDB. As general HFpEF therapies are often not successful, patient- and phenotype-individualized therapeutic strategies are warranted. Therefore, for the "obese HFpEF phenotype", a better understanding of the mechanistic parallels between both HFpEF and SDB is required, which may help to identify potential phenotype-individualized therapeutic strategies. Novel technologies like single-cell transcriptomics or CRISPR-Cas9 gene editing further broaden the groundwork for deeper insights into pathomechanisms and precision medicine.

Transcriptional regulation of macrophage inflammation in the heart failure with preserved ejection fraction: a translational study

Abstract Background/Introduction Inflammatory response is a key player in heart failure with preserved ejection fraction (HFpEF) but the underlying mechanisms are poorly understood (1). Recent studies have shown a critical involvement of cardiac macrophage recruitment and activation in myocardial remodelling (2,3). Purpose here we sought to determine the role of macrophage inflammation in experimental and human HFpEF. Methods We employed a translational approach combining human and murine LV myocardial tissue, FACS analysis of cardiac immune cells, in vitro experiments in primary macrophages and cardiac cells as well as ex vivo functional analyses in LV tissues. Human LV myocardial samples were used to evaluate the pro-inflammatory activity of macrophages in the HFpEF myocardium. Induction of HFpEF in mice was done through a validated mouse model combining metabolic (high-fat diet) and hemodynamic stress (L-NAME). Cardiac function was investigated by high resolution ultrasound imaging (Vevo3100) and the LV myocardial samples were used to study the macrophage polarization and their inflammatory activity. Based on interrogation of available RNA-seq datasets –showing the transcriptional repressor NCOR1 as a relevant signature in macrophages during cardiac inflammation, we generated myeloid cell-specific NCOR1 knockout (Ncor1-KO) transgenic mice to investigate the in vivo effects of NCOR1 deletion on the HFpEF phenotype. In vitro experiments included RAW 264.7 cells polarization through a metabolic stress model via palmitic acid (PA) and the assessment of macrophage phenotype switching in the presence or the absence of NCOR1. To study the crosstalk of macrophages with the surrounding cardiac cells, cardiomyocytes (H9c2) and endothelial cells (HAECS) were exposed to conditioned media from cultured RAW. Afterwards, cellular function and the pro-inflammatory cytokine levels were investigated. Results The expression of macrophage markers in human LV specimens showed an increase in pro-inflammatory macrophages (M1) and a decrease in regulatory macrophages (M2) as compared to age-matched control mice. HFpEF mice showed increased expression of vascular adhesion molecules (ICAM1, ICAM2, E-selectin) and a significant recruitment of M1 macrophages to the myocardium. Of interest, cardiac function and myocardial inflammation (TNF-a, IL6, IL-1b) were significantly reduced in Ncor1-KO mice. In vitro assays showed that stimulation of macrophages with PA induced M1 type switch and increased NCOR1, TNF-a, IL-6, and IL-1b levels, whereas NCOR1 depletion prevented detrimental changes of macrophage secretome (Fig.2). Conclusion NCOR1 is a crucial co-regulator of immune response and macrophage inflammation in the heart. Our findings pave the way for mechanism-based therapies to prevent HFpEF development.

Association between omentin-1 and heart failure with preserved ejection fraction in Chinese elderly patients.

Omentin-1 is a novel adipokine and is associated with chronic inflammation and cardiovascular diseases. However, it remains unclear whether omentin-1 levels are associated with diagnostic significance in elderly patients with heart failure with preserved ejection fraction (HFpEF). This study aimed to investigate the correlation between omentin-1 and HFpEF in Chinese elderly patients. Omentin-1 may be invovled in HFpEF and there may be a difference of omentin-1 levels between HFpEF and control. 217 subjects were selected, including 115 patients with HFpEF and 102 control subjects. Enzyme-linked immuno sorbent assay (ELISA) was used to detect plasma levels of omentin-1, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). The receiver operating characteristics (ROC) curve was used to examine the diagnostic performance of omentin-1 in HFpEF. The levels of omentin-1 decreased significantly in the HFpEF group (14.02 ± 8.35 vs. 19.74 ± 8.45 ng/mL, p < .001), while NT-proBNP, IL-6, and TNF-α levels were significantly increased in the HFpEF group compared with the control group. Spearman correlation analysis showed that omentin-1 levels were negatively correlated with E/e' (r = -.340, p < .001). The multivariate logistic regression analysis indicated that omentin-1 was an independent protective factor for HFpEF (odd ratio = 0.948, 95% confidence interval [CI] 0.905-0.993, p = .025). Omentin-1 levels were negatively correlated with NT-proBNP (r = -.273, p < .001) and TNF-α (r = -.221, p = .001). Diagnostic efficiency by ROC curve analysis in the patients with HFpEF showed that the area under the curve (AUC) for omentin-1 was equivalent to NT-proBNP (AUC: 0.734, 95%CI 0.667-0.802; AUC: 0.800, 95%CI 0.738-0.861). Subgroup analysis showed that in the patients between the age of 70 and 80, the predictive capability of omentin-1 was stronger than NT-proBNP (AUC: 0.809, 95%CI 0.680-0.937; AUC: 0.674, 95%CI 0.514-0.833). Omentin-1 levels which were associated with inflammation, were decreased in the HFpEF patients. It could be regarded as a valuable biomarker for the occurrence and development of HFpEF in elderly patients.

Abstract 12425: Stim1 Deletion in Treg Cell Protects From HFpEF Pathogenesis

Introduction: Heart failure with preserved ejection fraction (HFpEF) is a cardiovascular disease that remains untreatable in its pathogenesis. Therefore, there is a critical need to uncover the cellular and molecular mechanisms underlying HFpEF pathogenesis and identify potential targets for treatment that can enhance cardiac function and restrict disease progression. Previous studies have shown that Treg cells are crucial in hypertension-induced cardiovascular complications and metabolic dysregulation. Moreover, the function of Stromal interaction molecule 1 (STIM1) varies depending on the cell type. Hypothesis: We hypothesize that the deletion of STIM1 in Treg cells can protect against the development of HFpEF and its associated conditions. Methods: Male mice aged eight weeks (Stim1 flx/flx and Treg Stim1-/- ) were divided into four groups: control groups receiving a standard diet and water for five weeks, and HFpEF groups fed a high-fat diet (HFD) and N[w]-nitro-l-arginine methyl ester (L-NAME - 0.5g/L) in the drinking water for five weeks. Various measurements and assessments were conducted, including echocardiography, evaluations of metabolism and hypertension, analysis of heart and kidney injury markers, and assessment of vascular endothelial function. Results: After five weeks, Stim1 flx/flx mice subjected to HFD and L-NAME displayed evidence of HFpEF, including hypertension, metabolic disorders, cardiac hypertrophy with fibrosis, kidney injury with fibrosis, impaired exercise tolerance and vascular endothelial function, increased body weight and E/E' ratio, reduced cardiac index, and unchanged ejection fraction. Interestingly, Treg Stim1-/- mice were protected against HFD and L-NAME-induced HFpEF and its associated pathologies. Conclusions: These findings underscore the significance of targeting STIM1 in Treg cells to protect from the development and pathogenesis of HFpEF.

Abstract 13706: Determinants of Right Ventricular Dysfunction in Patients With Heart Failure With Preserved Ejection Fraction: The PARAGON-HF Trial Experience

Introduction: Right ventricular dysfunction (RVD) is a major prognostic factor in patients with heart failure with preserved ejection fraction (HFpEF), however determinants of RVD in HFpEF are not well described. Although sex-specific mechanisms have been incriminated in the development of HFpEF, it is unclear whether this is also true for RVD. Goals: (1) Assess the prevalence of RVD (defined as a tricuspid annular plane systolic excursion [TAPSE] &lt;1.7 cm, a fractional area change [FAC] &lt;35% or a RV free wall longitudinal strain [RVFWLS] &lt;20%, absolute value) in patients with HFpEF; (2) identify determinants of RVD, overall and according to sex, in patients with HFpEF. Methods: We used data from patients enrolled in the echocardiographic sub-study of the PARAGON-HF trial with adequate image quality (N=809, 53% women, mean age 74±8 years). Determinants of RVD, in the whole study population and according to sex, were identified using a multivariable logistic regression model. Results: There were 461 patients (57%) with RVD. After multivariable adjustment, RVD was cross-sectionally associated with a history of atrial fibrillation of flutter (AFF), older age, higher heart rate, greater LV mean wall thickness and higher NT-proBNP values. Systolic blood pressure and LV global longitudinal strain (absolute value) showed an inverse association ( Figure ). These results were consistent between men and women, except for AFF and LV mean wall thickness, which were associated with a greater likelihood of RVD in men (OR 2.46, 95%CI 1.33-4.56, OR 1.61, 95%CI 1.18-2.21 respectively) but not in women (OR 0.99, 95%CI 0.58-1.68, OR 0.90 95%CI 0.69-1.17 respectively, p-values for interaction=0.028 and 0.006). Conclusions: RVD was highly prevalent in our study population. Determinants of RVD included AFF, LV remodeling and systolic impairment, and increased NT-proBNP levels. Differences between men and women suggest gender-specific mechanisms in the development of RVD in HFpEF.

Abstract 18068: Isometric Handgrip Exercise Myocardial Perfusion Reserve Correlates With Coronary Microvascular Dysfunction and Abnormal Left Ventricular Strain: A Report From the Women’s Ischemia Syndrome Evaluation Pre-Heart Failure With Preserved Ejection Fraction Study

Background: Impaired coronary artery response to isometric handgrip exercise (IHE) has previously been demonstrated to reflect endothelial dysfunction, an important contributor to ischemia with no obstructive coronary arteries (INOCA) and coronary microvascular dysfunction (CMD). Stress perfusion cardiac magnetic resonance (CMR) imaging is typically performed with pharmacologic stress using myocardial perfusion reserve index (MPRI) as a measure of CMD. IHE-MPRI has not been comprehensively studied in patients with INOCA, who are at risk for heart failure with preserved ejection fraction (HFpEF). Hypothesis: IHE-MPRI is related to CMD measured by pharm-MPRI and left ventricular (LV) structural and functional abnormalities in INOCA patients at risk for HFpEF. Methods: Participants with INOCA underwent comprehensive CMR with first-pass perfusion with adenosine or regadenoson, rest, and IHE. MPRI was adjusted to rest rate-pressure product (RPP). Lack of a satisfactory IHE response (defined as increase in heart rate≥10 bpm or systolic blood pressure ≥10 mmHg) was excluded. CMR measures of LV structure, function, MPRI, T1 and T2 mapping were analyzed using commercial software, blinded to clinical data. Pearson correlations were performed. Results: Of the participants (n=44) with IHE-MPRI, mean age was 55±11 years, body mass index 27±7 kg/m 2 , and 98% female, 31% hypertension, 12.5% diabetes, 19% hyperlipidemia. IHE-MPRI adjusted for rest RPP significantly correlated positively with pharm-MPRI and inversely with time to peak strain, diastolic strain measures and myocardial T2 ( Figure ). IHE-MPRI was not related to resting or IHE heart rate, systolic strain, LV mass, volumes, mass-volume ratio, native T1 or extracellular volume. Conclusion: IHE-MPRI relates to CMD and LV strain among patients with INOCA. Measurement of IHE-MPRI may improve understanding of CMD and LV structural and functional abnormalities that may contribute to development of HFpEF.

Myocardial fibrosis and prognosis in heart failure with preserved ejection fraction: a pooled analysis of 12 cohort studies.

Heart failure with preserved ejection fraction (HFpEF) is a syndrome with significant clinical heterogeneity. Myocardial fibrosis has been considered a common pathological process in the development and progress of HFpEF. This study aimed to consolidate data on the prognostic effect of myocardial fibrosis, evaluated by cardiovascular magnetic resonance (CMR) imaging in patients with HFpEF. Three medical databases were searched for potentially related articles up to February 28, 2023. Cohort studies reporting associations between myocardial fibrosis and risk of all-cause mortality or composite major adverse cardiac outcomes (MACE) were included. Cardiac fibrosis was evaluated by CMR metrics, including late gadolinium enhancement (LGE) or myocardial extracellular volume (ECV). The hazard ratios (HRs) and 95% confidence intervals (CI) of the outcomes for higher myocardial fibrosis were calculated. Twelve studies with 2787 patients with HFpEF were included for analysis. After a median follow-up duration of 31.2 months, a higher level of cardiac fibrosis was associated with a significant increase in the risk of MACE (HR = 1.34, 95% CI = 1.14-1.57) and all-cause mortality (HR = 1.74, 95% CI = 1.27-2.39), respectively. Furthermore, the increased risk of outcomes was both observed when cardiac fibrosis was defined according to LGE or ECV, respectively. Higher burden of myocardial fibrosis evaluated by CMR can predict a poor prognosis in patients with HFpEF. Evaluation of LGE or ECV based on CMR could be recommended in these patients for risk stratification and guiding further treatment. Inclusion of cardiovascular magnetic resonance examination in the diagnostic and risk-evaluation algorithms in patients with heart failure with preserved ejection fraction should be considered in clinical practice and future studies. • Myocardial fibrosis is a common pathological process in heart failure with preserved ejection fraction. • A higher myocardial fibrosis burden on cardiac magnetic resonance predicts a poor prognosis in patients with heart failure with preserved ejection fraction. • Evaluation of myocardial fibrosis may be useful in patients with heart failure with preserved ejection fraction for risk stratification and treatment guidance.

Development of heart failure with preserved ejection fraction is independent of eosinophils in a preclinical model.

The increasing burden of heart failure with preserved ejection fraction (HFpEF) has become a global health problem. HFpEF is characterized by systematic inflammation, cardiac metabolic remodeling, and fibrosis. Eosinophils act as an essential but generally overlooked subgroup of white blood cells, which participate in cardiac fibrosis, as reported in several recent studies. Herein, we explored the role of eosinophils in a "two-hit" preclinical HFpEF model. The peripheral eosinophil counts were comparable between the normal chow and HFpEF mice. Deficiency of eosinophils failed to alter the phenotype of HFpEF. Conclusively, the development of HFpEF is independent of eosinophils in terms of the functional, biochemical, and histological results.

Left Ventricular Gene Expression in Heart Failure With Preserved Ejection Fraction-Profibrotic and Proinflammatory Pathways and Genes.

Heart failure with preserved ejection fraction (HFpEF) is increasingly prevalent and has few treatments. The molecular mechanisms and resultant signaling pathways that underlie the development of HFpEF are poorly defined. It has been proposed that activation of proinflammatory pathways plays a role in the development of cardiac fibrosis. The signature of gene expression (transcriptome) of previously validated left ventricular biopsies obtained from patients with HFpEF and matched referent controls allows for an unbiased assessment of proinflammatory and profibrotic signaling pathways and genes. Epicardial left ventricular biopsies from stringently selected HFpEF patients (HFpEF, n=16) and referent control patients (CTR, n=14) were obtained during aortocoronary bypass surgery. The subepicardial myocardium was flash-frozen to build a repository that was parallel-processed for RNA sequencing to allow for an unsupervised in-depth comparison of the left ventricular transcriptome. The average patient age was 67±10 years. When compared with controls, patients with HFpEF were hypertensive with a higher body mass index (kg/m2: 30±5 versus 37±6; P<0.01) and elevated NT-proBNP levels (pg/mL: 155 [89-328] versus 1554 [888-2178]; P<0.001). The transcriptome analysis revealed differential expression of 477 genes many of which were involved in profibrotic pathways including extracellular matrix production and posttranslational modification but no proinflammatory signature. The transcriptome analysis of left ventricular myocardial samples from patients with HFpEF confirms an overabundant extracellular matrix gene expression, the basis of myocardial fibrosis, without a signature of activated proinflammatory pathways or genes.