The effects of liraglutide and dapagliflozin on cardiac function and structure in a multi-hit mouse model of heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction in humans and mice: embracing clinical complexity in mouse models

Heart failure (HF) with preserved ejection fraction (HFpEF) is a multifactorial disease accounting for a large and increasing proportion of all clinical HF presentations. As a clinical syndrome, HFpEF is characterized by typical signs and symptoms of HF, a distinct cardiac phenotype and raised natriuretic peptides. Non-cardiac comorbidities frequently co-exist and contribute to the pathophysiology of HFpEF. To date, no therapy has proven to improve outcomes in HFpEF, with drug development hampered, at least partly, by lack of consensus on appropriate standards for pre-clinical HFpEF models. Recently, two clinical algorithms (HFA-PEFF and H₂FPEF scores) have been developed to improve and standardize the diagnosis of HFpEF. In this review, we evaluate the translational utility of HFpEF mouse models in the context of these HFpEF scores. We systematically recorded evidence of symptoms and signs of HF or clinical HFpEF features and included several cardiac and extra-cardiac parameters as well as age and sex for each HFpEF mouse model. We found that most of the pre-clinical HFpEF models do not meet the HFpEF clinical criteria, although some multifactorial models resemble human HFpEF to a reasonable extent. We therefore conclude that to optimize the translational value of mouse models to human HFpEF, a novel approach for the development of pre-clinical HFpEF models is needed, taking into account the complex HFpEF pathophysiology in humans.

Potential Therapeutic Benefits of Sodium-Glucose Cotransporter 2 Inhibitors in the Context of Ischemic Heart Failure: A State-Of-The-Art Review

Sodium-glucose cotransporter 2 (SGLT2) inhibitors are a class of anti-diabetic agents that block the reabsorption of glucose in the proximal convoluted tubule of the nephron, thereby contributing to glycosuria and lowering blood glucose levels. SGLT2 inhibitors have been associated with improved cardiovascular outcomes in patients with diabetes, including a reduced risk of cardiovascular death and hospitalizations for heart failure. Recently, DAPA-HF and EMPEROR REDUCED trials showed the beneficial cardiovascular effect of SGLT2 inhibitors in patients with heart failure with consistently reduced ejection fraction (HFrEF) regardless of the presence of diabetes. Moreover, some exploratory studies suggested that these drugs improve Left Ventricular (LV) systolic function and oppose LV adverse remodeling in patients with HFrEF. However, the exact mechanisms that mediated for this benefit are not fully understood. Beyond glycemic control, enhanced natriuresis, increased erythropoiesis, improved endothelial function, changes in myocardial metabolism, anti-inflammatory and anti-oxidative properties may all play an active role in SGLT2 inhibitors' cardiovascular benefits. A deep understanding of the pathophysiological interplay is key to define which HF phenotype could benefit more from SGLT2 inhibitors. Current clinical evidence on the comparison of different HF etiologies is limited to posthoc subgroup analysis of DAPA-HF and EMPEROR-REDUCED, which showed similar outcomes in patients with or without ischemic HF. On the other hand, in earlier studies of patients suffering from diabetes, rates of classic ischemic endpoints, such as myocardial infarction, stroke or coronary revascularization, did not differ between patients treated with SGLT2 inhibitors or placebo. The aim of this review is to discuss whether SGLT2 inhibitors may improve prognosis in patients with ischemic HF, not only in terms of reducing re-hospitalizations and improving left ventricular function but also by limiting coronary artery disease progression and ischemic burden.

The effects of liraglutide and dapagliflozin on cardiac function and structure in a multi-hit mouse model of heart failure with preserved ejection fraction

AIMS

Heart failure with preserved ejection fraction (HFpEF) is a multifactorial disease that constitutes several distinct phenotypes, including a common cardiometabolic phenotype with obesity and type 2 diabetes mellitus. Treatment options for HFpEF are limited, and development of novel therapeutics is hindered by the paucity of suitable preclinical HFpEF models that recapitulate the complexity of human HFpEF. Metabolic drugs, like glucagon-like peptide receptor agonist (GLP-1 RA) and sodium-glucose co-transporter 2 inhibitors (SGLT2i), have emerged as promising drugs to restore metabolic perturbations and may have value in the treatment of the cardiometabolic HFpEF phenotype. We aimed to develop a multifactorial HFpEF mouse model that closely resembles the cardiometabolic HFpEF phenotype, and evaluated the GLP-1 RA liraglutide (Lira) and the SGLT2i dapagliflozin (Dapa).

METHODS AND RESULTS

Aged (18-22 months old) female C57BL/6J mice were fed a standardized chow (CTRL) or high-fat diet (HFD) for 12 weeks. After 8 weeks HFD, angiotensin II (ANGII), was administered for 4 weeks via osmotic mini pumps. HFD + ANGII resulted in a cardiometabolic HFpEF phenotype, including obesity, impaired glucose handling, and metabolic dysregulation with inflammation. The multiple hit resulted in typical clinical HFpEF features, including cardiac hypertrophy and fibrosis with preserved fractional shortening but with impaired myocardial deformation, atrial enlargement, lung congestion, and elevated blood pressures. Treatment with Lira attenuated the cardiometabolic dysregulation and improved cardiac function, with reduced cardiac hypertrophy, less myocardial fibrosis, and attenuation of atrial weight, natriuretic peptide levels, and lung congestion. Dapa treatment improved glucose handling, but had mild effects on the HFpEF phenotype.

CONCLUSIONS

We developed a mouse model that recapitulates the human HFpEF disease, providing a novel opportunity to study disease pathogenesis and the development of enhanced therapeutic approaches. We furthermore show that attenuation of cardiometabolic dysregulation may represent a novel therapeutic target for the treatment of HFpEF.

Prostaglandin E1 attenuates AngII-induced cardiac hypertrophy via EP3 receptor activation and Netrin-1upregulation

AIMS

Pathological cardiac hypertrophy induced by activation of the renin-angiotensin-aldosterone system (RAAS) is one of the leading causes of heart failure. However, in current clinical practice, the strategy for targeting the RAAS is not sufficient to reverse hypertrophy. Here, we investigated the effect of prostaglandin E1 (PGE1) on angiotensin II (AngII)-induced cardiac hypertrophy and potential molecular mechanisms underlying the effect.

METHODS AND RESULTS

Adult male C57 mice were continuously infused with AngII or saline and treated daily with PGE1 or vehicle for two weeks. Neonatal rat cardiomyocytes were cultured to detect AngII-induced hypertrophic responses. We found that PGE1 ameliorated AngII-induced cardiac hypertrophy both in vivo and in vitro. The RNA sequencing (RNA-seq) and expression pattern analysis results suggest that Netrin-1 (Ntn1) is the specific target gene of PGE1. The protective effect of PGE1 was eliminated after knockdown of Ntn1. Moreover, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that the PGE1-mediated signaling pathway changes are associated with the mitogen-activated protein kinase (MAPK) pathway. PGE1 suppressed AngII-induced activation of the MAPK signaling pathway, and such an effect was attenuated by Ntn1 knockdown. Blockade of MAPK signaling rescued the phenotype of cardiomyocytes caused by Ntn1 knockdown, indicating that MAPK signaling may act as the downstream effector of Ntn1. Furthermore, inhibition of the E-prostanoid (EP) 3 receptor, as opposed to the EP1, EP2, or EP4 receptor, in cardiomyocytes reversed the effect of PGE1, and activation of EP3 by sulprostone, a specific agonist, mimicked the effect of PGE1.

CONCLUSION

In conclusion, PGE1 ameliorates AngII-induced cardiac hypertrophy through activation of the EP3 receptor and upregulation of Ntn1, which inhibits the downstream MAPK signaling pathway. Thus, targeting EP3, as well as the Ntn1-MAPK axis, may represent a novel approach for treating pathological cardiac hypertrophy.

Are fat and sugar just as detrimental in old age?

Aging and poor nutrition are independent risk factors for the development of chronic disease. When young animals are given diets high in fat or sugar, they exhibit hallmarks of aging like mitochondrial dysfunction and inflammation, and also develop a greater risk for age-related disease. The same mitochondrial dysfunction and inflammation that progress with aging may also further predispose older individuals to dietary insults by fat and sugar. The purpose of this work is to review the most recent studies that address the impact of fat and sugar consumption on hallmarks of aging (mitochondrial dysfunction and inflammation). Findings from these studies show that obesogenic, high-fat diets can exacerbate age-related disease and hallmarks of aging in young animals, but high-fat diets that are non-obesogenic may play a beneficial role in old age. In contrast, high-sugar diets do not require an obesogenic effect to induce mitochondrial dysfunction or inflammation in young rodents. Currently, there is a lack of experimental studies addressing the impact of sugar in the context of aging, even though empirical evidence points to the detrimental effect of sugar in aging by contributing to a variety of age-related diseases. Fig. 1 Mitochondrial dysfunction and altered cellular communication (e.g. inflammation) progress with advancing age and increase the risk for age-related disease (ARD). Given the physiological changes that occur with age, the impact of high-fat (HFD) and high-sugar diets (HSD) may differ in later and earlier stages of life. HFD can promote the development of hallmarks of aging in young animals and can also exacerbate the risk for ARD when consumed at an old age. However, non-obesogenic high-fat diets may also reduce the risk for ARD in old age by acting on these hallmarks of aging. On the other hand, HSD promotes mitochondrial dysfunction and inflammation without necessarily inducing weight gain in young animals. Empirical evidence points to sugar as a major contributor to age-related disease and more experimental studies are needed to clarify whether aged individuals are more susceptible to its effects.

SGLT2 inhibitors decrease cardiovascular death and heart failure hospitalizations in patients with heart failure: A systematic review and meta-analysis

BACKGROUND

Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce the composite of heart failure (HF) hospitalizations or cardiovascular mortality among patients with HF. However, the efficacy of SGLT2 inhibitors in secondary endpoints of randomized trials and in subgroups of HF patients is not well known.

METHODS

We performed a systematic review and meta-analysis of placebo-controlled, randomized trials of SGLT2 inhibitors in patients with HF. PubMed, Embase, and Cochrane databases were searched for trials published up to January 21, 2021. Data were extracted from published reports and quality assessment was performed per Cochrane recommendations. Hazard ratios (HRs) with 95% CI were pooled across trials. The primary endpoints of interest were all-cause and cardiovascular mortality.

RESULTS

Out of 3969 database results, 15 randomized trials and 20,241 patients were included; 10,594 (52·3%) received SGLT2 inhibitors. All-cause mortality (HR 0·86; 95% CI 0·79-0·94; p = 0·0007; I2=0%) and cardiovascular mortality (HR 0·86; 95% CI 0·78-0·96; p = 0·006; I2=0%) were significantly lower in patients treated with SGLT2 inhibitors compared with placebo. The composite of cardiovascular mortality, HF hospitalizations, or urgent visits for HF was significantly reduced with SGLT2 inhibitors in all the following subgroups: male, female, age < 65, age ≥ 65, race - Black and White, estimated glomerular filtration rate (eGFR) <60, eGFR ≥60, New York Heart Association (NYHA) class II, NYHA ≥III, and HF with preserved ejection fraction.

INTERPRETATION

In patients with HF, SGLT2 inhibitors significantly reduce all-cause and cardiovascular mortality compared with placebo. In addition, the composite of cardiovascular mortality or HF hospitalizations/urgent visits is reduced with SGLT2 inhibitors across subgroups of sex, age, race, eGFR, HF functional class, and ejection fraction.

Fighting HFpEF in women: taking aim at belly fat

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Sacubitril/valsartan inhibits obesity-associated diastolic dysfunction through suppression of ventricular-vascular stiffness

OBJECTIVE

Cardiac diastolic dysfunction (DD) and arterial stiffness are early manifestations of obesity-associated prediabetes, and both serve as risk factors for the development of heart failure with preserved ejection fraction (HFpEF). Since the incidence of DD and arterial stiffness are increasing worldwide due to exponential growth in obesity, an effective treatment is urgently needed to blunt their development and progression. Here we investigated whether the combination of an inhibitor of neprilysin (sacubitril), a natriuretic peptide-degrading enzyme, and an angiotensin II type 1 receptor blocker (valsartan), suppresses DD and arterial stiffness in an animal model of prediabetes more effectively than valsartan monotherapy.

METHODS

Sixteen-week-old male Zucker Obese rats (ZO; n = 64) were assigned randomly to 4 different groups: Group 1: saline control (ZOC); Group 2: sacubitril/valsartan (sac/val; 68 mg•kg-1•day-1; ZOSV); Group 3: valsartan (31 mg•kg-1•day-1; ZOV) and Group 4: hydralazine, an anti-hypertensive drug (30 mg•kg-1•day-1; ZOH). Six Zucker Lean (ZL) rats that received saline only (Group 5) served as lean controls (ZLC). Drugs were administered daily for 10 weeks by oral gavage.

RESULTS

Sac/val improved echocardiographic parameters of impaired left ventricular (LV) stiffness in untreated ZO rats, without altering the amount of food consumed or body weight gained. In addition to improving DD, sac/val decreased aortic stiffness and reversed impairment in nitric oxide-induced vascular relaxation in ZO rats. However, sac/val had no impact on LV hypertrophy. Notably, sac/val was more effective than val in ameliorating DD. Although, hydralazine was as effective as sac/val in improving these parameters, it adversely affected LV mass index. Further, cytokine array revealed distinct effects of sac/val, including marked suppression of Notch-1 by both valsartan and sac/val, suggesting that cardiovascular protection afforded by both share some common mechanisms; however, sac/val, but not val, increased IL-4, which is increasingly recognized for its cardiovascular protection, possibly contributing, in part, to more favorable effects of sac/val over val alone in improving obesity-associated DD.

CONCLUSIONS

These studies suggest that sac/val is superior to val in reversing obesity-associated DD. It is an effective drug combination to blunt progression of asymptomatic DD and vascular stiffness to HFpEF development in a preclinical model of obesity-associated prediabetes.

New antidiabetic therapy and HFpEF: light at the end of tunnel?

New antidiabetic therapy that includes sodium-glucose co-transporter 2 (SGLT2) inhibitors, glucagon-like peptide-1 receptor (GLP-1R) agonists, and dipeptidyl peptidase 4 (DPP-4) inhibitors showed significant benefit on cardiovascular outcomes in patients with and without type 2 diabetes mellitus, and this was particularly confirmed for SGLT2 inhibitors in subjects with heart failure (HF) with reduced ejection fraction (HFrEF). Their role on patients with HF with preserved ejection fraction (HFpEF) is still not elucidated, but encouraging results coming from the clinical studies indicate their beneficial role. The role of GLP-1R agonists and particularly DPP-4 inhibitors is less clear and debatable. Findings from the meta-analyses are sending positive message about the use of GLP-1R agonists in HFrEF therapy and revealed the improvement of left ventricular (LV) diastolic function in HFpEF. Nevertheless, the relevant medical societies still consider their effect as neutral or insufficiently investigated in HF patients. The impact of DPP-4 inhibitors in HF is the most controversial due to conflicting data that range from negative impact and increased risk of hospitalization due to HF, throughout neutral effect, to beneficial influence on LV diastolic dysfunction. However, this is a very heterogeneous group of medications and some professional societies made clear discrepancy between saxagliptin that might increase risk of HF hospitalization and those DPP-4 inhibitors that have no effect on hospitalization. The aim of this review is to summarize current clinical evidence about the effect of new antidiabetic medications on LV diastolic function and their potential benefits in HFpEF patients.

Glucagon-like peptide-1 (GLP-1) receptor agonists and their cardiovascular benefits-The role of the GLP-1 receptor

Cardiovascular outcome trials revealed cardiovascular benefits for type 2 diabetes mellitus patients when treated with long‐acting glucagon‐like peptide‐1 (GLP‐1) receptor agonists. In the last decade, major advances were made characterising the physiological effects of GLP‐1 and its action on numerous targets including brain, liver, kidney, heart and blood vessels. However, the effects of GLP‐1 and receptor agonists, and the GLP‐1 receptor on the cardiovascular system have not been fully elucidated. We compare results from cardiovascular outcome trials of GLP‐1 receptor agonists and review pleiotropic clinical and preclinical data concerning cardiovascular protection beyond glycaemic control. We address current knowledge on GLP‐1 and receptor agonist actions on the heart, vasculature, inflammatory cells and platelets, and discuss evidence for GLP‐1 receptor‐dependent versus independent effects secondary of GLP‐1 metabolites. We conclude that the favourable cardiovascular profile of GLP‐1 receptor agonists might expand their therapeutic use for treating cardiovascular disease even in non‐diabetic populations.

Mechanisms and Perspectives of Sodium-Glucose Co-transporter 2 Inhibitors in Heart Failure

Heart failure (HF) is a common complication or late-stage manifestation of various heart diseases. Numerous risk factors and underlying causes may contribute to the occurrence and progression of HF. The pathophysiological mechanisms of HF are very complicated. Despite accumulating advances in treatment for HF during recent decades, it remains an intractable clinical syndrome with poor outcomes, significantly reducing the quality of life and expectancy of patients, and imposing a heavy economic burden on society and families. Although initially classified as antidiabetic agents, sodium-glucose co-transporter 2 (SGLT2) inhibitors have demonstrated reduced the prevalence of hospitalization for HF, cardiovascular death, and all-cause death in several large-scale randomized controlled clinical trials. These beneficial effects of SGLT-2 inhibitors can be attributed to multiple hemodynamic, inflammatory and metabolic mechanisms, not only reducing the serum glucose level. SGLT2 inhibitors have been used increasingly in treatment for patients with HF with reduced ejection fraction due to their surprising performance in improving the prognosis. In addition, their roles and mechanisms in patients with HF with preserved ejection fraction or acute HF have also attracted attention. In this review article, we discuss the possible mechanisms and applications of SGLT2 inhibitors in HF.