Heart failure and diabetes: metabolic alterations and therapeutic interventions: a state-of-the-art review from the Translational Research Committee of the Heart Failure Association-European Society of Cardiology

Changes in Patterns of Physical Activity and Risk of Heart Failure in Newly Diagnosed Diabetes Mellitus Patients

BACKGROUND

Exercise is recommended for type 2 diabetes mellitus (T2DM) patients to prevent cardiovascular disease. However, the effects of physical activity (PA) for reducing the risk of heart failure (HF) has yet to be elucidated. We aimed to assess the effect of changes in patterns of PA on incident HF, especially in newly diagnosed diabetic patients.

METHODS

We examined health examination data and claims records of 294,528 participants from the Korean National Health Insurance Service who underwent health examinations between 2009 and 2012 and were newly diagnosed with T2DM. Participants were classified into the four groups according to changes in PA between before and after the diagnosis of T2DM: continuously inactive, inactive to active, active to inactive, and continuously active. The development of HF was analyzed until 2017.

RESULTS

As compared with those who were continuously inactive, those who became physically active after diagnosis showed a reduced risk for HF (adjusted hazard ratio [aHR], 0.79; 95% confidence interval [CI], 0.66 to 0.93). Those who were continuously active had the lowest risk for HF (aHR, 0.77; 95% CI, 0.62 to 0.96). As compared with those who were inactive, those who exercised regularly, either performing vigorous or moderate PA, had a lower HF risk (aHR, 0.79; 95% CI, 0.69 to 0.91).

CONCLUSION

Among individuals with newly diagnosed T2DM, the risk of HF was reduced in those with higher levels of PA after diagnosis was made. Our results suggest either increasing or maintaining the frequency of PA after the diagnosis of T2DM may lower the risk of HF.

Endocrine system dysfunction and chronic heart failure: a clinical perspective

Chronic heart failure (CHF) leads to an excess of urgent ambulatory visits, recurrent hospital admissions, morbidity, and mortality regardless of medical and non-medical management of the disease. This excess of risk may be attributable, at least in part, to comorbid conditions influencing the development and progression of CHF. In this perspective, the authors examined and described the most common endocrine disorders observed in patients with CHF, particularly in individuals with reduced ejection fraction, aiming to qualify the risks, quantify the epidemiological burden and discuss about the potential role of endocrine treatment. Thyroid dysfunction is commonly observed in patients with CHF, and sometimes it could be the consequence of certain medications (e.g., amiodarone). Male and female hypogonadism may also coexist in this clinical context, contributing to deteriorating the prognosis of these patients. Furthermore, growth hormone deficiency may affect the development of adult myocardium and predispose to CHF. Limited recommendation suggests to screen endocrine disorders in CHF patients, but it could be interesting to evaluate possible endocrine dysfunction in this setting, especially when a high suspicion coexists. Data referring to long-term safety and effectiveness of endocrine treatments in patients with CHF are limited, and their impact on several "hard" endpoints (such as hospital admission, all-cause, and cardiovascular mortality) are still poorly understood.

Incorporation of natriuretic peptides with clinical risk scores to predict heart failure among individuals with dysglycaemia

AIMS

To evaluate the performance of the WATCH-DM risk score, a clinical risk score for heart failure (HF), in patients with dysglycaemia and in combination with natriuretic peptides (NPs).

METHODS AND RESULTS

Adults with diabetes/pre-diabetes free of HF at baseline from four cohort studies (ARIC, CHS, FHS, and MESA) were included. The machine learning- [WATCH-DM(ml)] and integer-based [WATCH-DM(i)] scores were used to estimate the 5-year risk of incident HF. Discrimination was assessed by Harrell's concordance index (C-index) and calibration by the Greenwood-Nam-D'Agostino (GND) statistic. Improvement in model performance with the addition of NP levels was assessed by C-index and continuous net reclassification improvement (NRI). Of the 8938 participants included, 3554 (39.8%) had diabetes and 432 (4.8%) developed HF within 5 years. The WATCH-DM(ml) and WATCH-DM(i) scores demonstrated high discrimination for predicting HF risk among individuals with dysglycaemia (C-indices = 0.80 and 0.71, respectively), with no evidence of miscalibration (GND P ≥0.10). The C-index of elevated NP levels alone for predicting incident HF among individuals with dysglycaemia was significantly higher among participants with low/intermediate (<13) vs. high (≥13) WATCH-DM(i) scores [0.71 (95% confidence interval 0.68-0.74) vs. 0.64 (95% confidence interval 0.61-0.66)]. When NP levels were combined with the WATCH-DM(i) score, HF risk discrimination improvement and NRI varied across the spectrum of risk with greater improvement observed at low/intermediate risk [WATCH-DM(i) <13] vs. high risk [WATCH-DM(i) ≥13] (C-index = 0.73 vs. 0.71; NRI = 0.45 vs. 0.17).

CONCLUSION

The WATCH-DM risk score can accurately predict incident HF risk in community-based individuals with dysglycaemia. The addition of NP levels is associated with greater improvement in the HF risk prediction performance among individuals with low/intermediate risk than those with high risk.

Energy metabolism homeostasis in cardiovascular diseases

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in the general population. Energy metabolism disturbance is one of the early abnormalities in CVDs, such as coronary heart disease, diabetic cardiomyopathy, and heart failure. To explore the role of myocardial energy homeostasis disturbance in CVDs, it is important to understand myocardial metabolism in the normal heart and their function in the complex pathophysiology of CVDs. In this article, we summarized lipid metabolism/lipotoxicity and glucose metabolism/insulin resistance in the heart, focused on the metabolic regulation during neonatal and ageing heart, proposed potential metabolic mechanisms for cardiac regeneration and degeneration. We provided an overview of emerging molecular network among cardiac proliferation, regeneration, and metabolic disturbance. These novel targets promise a new era for the treatment of CVDs.

Hyperglycemic memory in diabetic cardiomyopathy

Cardiovascular diseases account for approximately 80% of deaths among individuals with diabetes mellitus, with diabetic cardiomyopathy as the major diabetic cardiovascular complication. Hyperglycemia is a symptom that abnormally activates multiple downstream pathways and contributes to cardiac hypertrophy, fibrosis, apoptosis, and other pathophysiological changes. Although glycemic control has long been at the center of diabetes therapy, multicenter randomized clinical studies have revealed that intensive glycemic control fails to reduce heart failure-associated hospitalization and mortality in patients with diabetes. This finding indicates that hyperglycemic stress persists in the cardiovascular system of patients with diabetes even if blood glucose level is tightly controlled to the normal level. This process is now referred to as hyperglycemic memory (HGM) phenomenon. We briefly reviewed herein the current advances that have been achieved in research on the underlying mechanisms of HGM in diabetic cardiomyopathy.

Sacubitril-Valsartan, Clinical Benefits and Related Mechanisms of Action in Heart Failure With Reduced Ejection Fraction. A Review

Heart failure (HF) is a clinical syndrome characterized by the presence of dyspnea or limited exertion due to impaired cardiac ventricular filling and/or blood ejection. Because of its high prevalence, it is a major health and economic burden worldwide. Several mechanisms are involved in the pathophysiology of HF. First, the renin-angiotensin-aldosterone system (RAAS) is over-activated, causing vasoconstriction, hypertension, elevated aldosterone levels and sympathetic tone, and eventually cardiac remodeling. Second, an endogenous compensatory mechanism, the natriuretic peptide (NP) system is also activated, albeit insufficiently to counteract the RAAS effects. Since NPs are degraded by the enzyme neprilysin, it was hypothesized that its inhibition could be an important therapeutic target in HF. Sacubitril/valsartan is the first of the class of dual neprilysin and angiotensin receptor inhibitors (ARNI). In patients with HFrEF, treatment with sacubitril/valsartan has demonstrated to significantly reduce mortality and the rates of hospitalization and rehospitalization for HF when compared to enalapril. This communication reviews in detail the demonstrated benefits of sacubitril/valsartan in the treatment of patients with HFrEF, including reduction of mortality and disease progression as well as improvement in cardiac remodeling and quality of life. The hemodynamic and organic effects arising from its dual mechanism of action, including the impact of neprilysin inhibition at the renal level, especially relevant in patients with type 2 diabetes mellitus, are also reviewed. Finally, the evidence on the demonstrated safety and tolerability profile of sacubitril/valsartan in the different subpopulations studied has been compiled. The review of this evidence, together with the recommendations of the latest clinical guidelines, position sacubitril/valsartan as a fundamental pillar in the treatment of patients with HFrEF.

Therapeutic Approach of Flavonoid in Ameliorating Diabetic Cardiomyopathy by Targeting Mitochondrial-Induced Oxidative Stress

Diabetes cardiomyopathy is one of the key factors of mortality among diabetic patients around the globe. One of the prior contributors to the progression of diabetic cardiomyopathy is cardiac mitochondrial dysfunction. The cardiac mitochondrial dysfunction can induce oxidative stress in cardiomyocytes and was found to be the cause of majority of the heart morphological and dynamical changes in diabetic cardiomyopathy. To slow down the occurrence of diabetic cardiomyopathy, it is crucial to discover therapeutic agents that target mitochondrial-induced oxidative stress. Flavonoid is a plentiful phytochemical in plants that shows a wide range of biological actions against human diseases. Flavonoids have been extensively documented for their ability to protect the heart from diabetic cardiomyopathy. Flavonoids' ability to alleviate diabetic cardiomyopathy is primarily attributed to their antioxidant properties. In this review, we present the mechanisms involved in flavonoid therapies in ameliorating mitochondrial-induced oxidative stress in diabetic cardiomyopathy.

Left Ventricular Hypertrophy in Diabetic Cardiomyopathy: A Target for Intervention

Heart failure is an important manifestation of diabetic heart disease. Before the development of symptomatic heart failure, as much as 50% of patients with type 2 diabetes mellitus (T2DM) develop asymptomatic left ventricular dysfunction including left ventricular hypertrophy (LVH). Left ventricular hypertrophy (LVH) is highly prevalent in patients with T2DM and is a strong predictor of adverse cardiovascular outcomes including heart failure. Importantly regression of LVH with antihypertensive treatment especially renin angiotensin system blockers reduces cardiovascular morbidity and mortality. However, this approach is only partially effective since LVH persists in 20% of patients with hypertension who attain target blood pressure, implicating the role of other potential mechanisms in the development of LVH. Moreover, the pathophysiology of LVH in T2DM remains unclear and is not fully explained by the hyperglycemia-associated cellular alterations. There is a growing body of evidence that supports the role of inflammation, oxidative stress, AMP-activated kinase (AMPK) and insulin resistance in mediating the development of LVH. The recognition of asymptomatic LVH may offer an opportune target for intervention with cardio-protective therapy in these at-risk patients. In this article, we provide a review of some of the key clinical studies that evaluated the effects of allopurinol, SGLT2 inhibitor and metformin in regressing LVH in patients with and without T2DM.

Mitophagy in Diabetic Cardiomyopathy: Roles and Mechanisms

Cardiovascular disease is the leading complication of diabetes mellitus (DM), and diabetic cardiomyopathy (DCM) is a major cause of mortality in diabetic patients. Multiple pathophysiologic mechanisms, including myocardial insulin resistance, oxidative stress and inflammation, are involved in the development of DCM. Recent studies have shown that mitochondrial dysfunction makes a substantial contribution to the development of DCM. Mitophagy is a type of autophagy that takes place in dysfunctional mitochondria, and it plays a key role in mitochondrial quality control. Although the precise molecular mechanisms of mitophagy in DCM have yet to be fully clarified, recent findings imply that mitophagy improves cardiac function in the diabetic heart. However, excessive mitophagy may exacerbate myocardial damage in patients with DCM. In this review, we aim to provide a comprehensive overview of mitochondrial quality control and the dual roles of mitophagy in DCM. We also propose that a balance between mitochondrial biogenesis and mitophagy is essential for the maintenance of cellular metabolism in the diabetic heart.

Diabetes status-related differences in risk factors and mediators of heart failure in the general population: results from the MORGAM/BiomarCaRE consortium

Background

The risk of heart failure among diabetic individuals is high, even under tight glycemic control. The correlates and mediators of heart failure risk in individuals with diabetes need more elucidation in large population-based cohorts with long follow-up times and a wide panel of biologically relevant biomarkers.

Methods

In a population-based sample of 3834 diabetic and 90,177 non-diabetic individuals, proportional hazards models and mediation analysis were used to assess the relation of conventional heart failure risk factors and biomarkers with incident heart failure.

Results

Over a median follow-up of 13.8 years, a total of 652 (17.0%) and 5524 (6.1%) cases of incident heart failure were observed in participants with and without diabetes, respectively. 51.4% were women and the mean age at baseline was 48.7 (standard deviation [SD] 12.5) years. The multivariable-adjusted hazard ratio (HR) for heart failure among diabetic individuals was 2.70 (95% confidence interval, 2.49–2.93) compared to non-diabetic participants. In the multivariable-adjusted Cox models, conventional cardiovascular disease risk factors, such as smoking (diabetes: HR 2.07 [1.59–2.69]; non-diabetes: HR 1.85 [1.68–2.02]), BMI (diabetes: HR 1.30 [1.18–1.42]; non-diabetes: HR 1.40 [1.35–1.47]), baseline myocardial infarction (diabetes: HR 2.06 [1.55–2.75]; non-diabetes: HR 2.86 [2.50–3.28]), and baseline atrial fibrillation (diabetes: HR 1.51 [0.82–2.80]; non-diabetes: HR 2.97 [2.21–4.00]) had the strongest associations with incident heart failure. In addition, biomarkers for cardiac strain (represented by nT-proBNP, diabetes: HR 1.26 [1.19–1.34]; non-diabetes: HR 1.43 [1.39–1.47]), myocardial injury (hs-TnI, diabetes: HR 1.10 [1.04–1.16]; non-diabetes: HR 1.13 [1.10–1.16]), and inflammation (hs-CRP, diabetes: HR 1.13 [1.03–1.24]; non-diabetes: HR 1.29 [1.25–1.34]) were also associated with incident heart failure. In general, all these associations were equally strong in non-diabetic and diabetic individuals. However, the strongest mediators of heart failure in diabetes were the direct effect of diabetes status itself (relative effect share 43.1% [33.9–52.3] and indirect effects (effect share 56.9% [47.7-66.1]) mediated by obesity (BMI, 13.2% [10.3–16.2]), cardiac strain/volume overload (nT-proBNP, 8.4% [-0.7–17.4]), and hyperglycemia (glucose, 12.0% [4.2–19.9]).

Conclusions

The findings suggest that the main mediators of heart failure in diabetes are obesity, hyperglycemia, and cardiac strain/volume overload. Conventional cardiovascular risk factors are strongly related to incident heart failure, but these associations are not stronger in diabetic than in non-diabetic individuals. Active measurement of relevant biomarkers could potentially be used to improve prevention and prediction of heart failure in high-risk diabetic patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-021-01378-4.

Similarities and Differences Between HFmrEF and HFpEF

The new guidelines classify heart failure (HF) into three subgroups based on the ejection fraction (EF): HF with reduced EF (HFrEF), HF with mid-range EF (HFmrEF), and HF with preserved EF (HFpEF). The new guidelines regarding the declaration of HFmrEF as a unique phenotype have achieved the goal of stimulating research on the basic characteristics, pathophysiology, and treatment of HF patients with a left ventricular EF of 40-49%. Patients with HFmrEF have more often been described as an intermediate population between HFrEF and HFpEF patients; however, with regard to etiology and clinical indicators, they are more similar to the HFrEF population. Concerning clinical prognosis, they are closer to HFpEF because both populations have a good prognosis and quality of life. Meanwhile, growing evidence indicates that HFmrEF and HFpEF show heterogeneity in presentation and pathophysiology, and the emergence of this heterogeneity often plays a crucial role in the prognosis and treatment of the disease. To date, the exact mechanisms and effective treatment strategies of HFmrEF and HFpEF are still poorly understood, but some of the current evidence, from observational studies and post-hoc analyses of randomized controlled trials, have shown that patients with HFmrEF may benefit more from HFrEF treatment strategies, such as beta-blockers, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, mineralocorticoid receptor antagonists, and sacubitril/valsartan. This review summarizes available data from current clinical practice and mechanistic studies in terms of epidemiology, etiology, clinical indicators, mechanisms, and treatments to discuss the potential association between HFmrEF and HFpEF patients.

[Update on diagnostics and treatment of heart failure]

Inzidenz und Prävalenz der Herzinsuffizienz steigen weltweit. Trotz zahlreicher wissenschaftlicher und klinischer Innovationen ist sie weiterhin mit einer hohen Morbidität und Mortalität behaftet, sodass eine leitliniengerechte Diagnostik und Therapie von entscheidender Bedeutung sind. Die kardiale Dekompensation zählt zu den häufigsten Aufnahmegründen in deutschen Krankenhäusern. Somit stellt die Behandlung herzinsuffizienter Patienten eine erhebliche Herausforderung für das deutsche Gesundheitssystem dar. Dieser Artikel fasst die neuesten wissenschaftlichen Erkenntnisse zur akuten und chronischen Herzinsuffizienz der Jahre 2018 bis 2020 zusammen.

Neutrophils pro-inflammatory and anti-inflammatory cytokine release in patients with heart failure and reduced ejection fraction

AIMS

Heart failure with reduced ejection fraction (HFrEF) is characterized by sub-clinical inflammation. Changes in selected biomarkers of inflammation concomitant with the release of pro-inflammatory and anti-inflammatory cytokines by neutrophils have not been investigated in patients with HFrEF.

METHODS AND RESULTS

Fifty-two patients, aged 68.8 ± 1.7 years, with HFrEF and left ventricular ejection fraction 28.7 ± 1.0%, and 21 healthy controls (CTL) were recruited. Twenty-five HF patients had type 2 diabetes. Venous blood samples from HF and CTL were collected once. Neutrophil-derived pro-inflammatory and anti-inflammatory cytokine levels were assessed in plasma by ELISA. Plasma biomarkers assessed included: C-reactive protein (CRP), vascular endothelial growth factor (VEGF), interleukins (IL)-6, -8, -1 receptor antagonist (-1RA), nitric oxide (NO), soluble intercellular adhesion molecule-1 (sICAM-1), vascular cell adhesion molecule 1 (sVCAM-1) and E-Selectin (sE-Sel). Neutrophils were isolated and stimulated with various agonists to promote VEGF, IL-6, IL-8, and IL-1RA release. Compared with CTL, HFrEF patients showed a marked decrease in circulating VEGF [178.0 (interquartile range; IQR 99.6; 239.2) vs. 16.2 (IQR 9.3; 20.2) pg/mL, P ≤ 0.001] and NO [45.2 (IQR 42.1; 57.6) vs. 40.6 (IQR 30.4; 47.1) pg/mL, P = 0.0234]. All other circulating biomarkers were significantly elevated. Neutrophils isolated from patients with HFrEF exhibited a greater IL-8 release in response to LPS [1.2 ± 0.1 (CTL); 10.4 ± 1.6 ng/mL (HFrEF) and 12.4 ± 1.6 ng/mL (HFrEF and DM), P ≤ 0.001]. IL-6 release in response to LPS was not changed in HFrEF patients without diabetes, whereas it was significantly increased in patients with HFrEF and diabetes [46.7 ± 3.9 (CTL) vs. 165.8 ± 48.0 pg/mL (HFrEF), P = 0.1713 and vs. 397.7 ± 67.4 pg/mL (HFrEF and DM), P ≤ 0.001]. In contrast, the release of VEGF and IL-1RA was significantly reduced in HFrEF (VEGF; TNF-α: 38.6 ± 3.1 and LPS: 25.3 ± 2.6 pg/mL; IL1RA; TNF-α: 0.6 ± 0.04 and LPS: 0.3 ± 0.02 ng/mL) compared with CTL (VEGF; TNF-α: 60.0 ± 9.4 and LPS: 41.2 ± 5.9 pg/mL; IL1RA; TNF-α: 3.3 ± 0.2 and LPS: 2.3 ± 0.1 ng/mL).

CONCLUSIONS

Patients with HFrEF exhibit a significant decrease in circulating VEGF. The release of VEGF and both pro-inflammatory and anti-inflammatory cytokines from the stimulated neutrophils is markedly altered in these patients. The clinical significance of these findings deserves further investigation.

The PPARβ/δ-AMPK Connection in the Treatment of Insulin Resistance

The current treatment options for type 2 diabetes mellitus do not adequately control the disease in many patients. Consequently, there is a need for new drugs to prevent and treat type 2 diabetes mellitus. Among the new potential pharmacological strategies, activators of peroxisome proliferator-activated receptor (PPAR)β/δ show promise. Remarkably, most of the antidiabetic effects of PPARβ/δ agonists involve AMP-activated protein kinase (AMPK) activation. This review summarizes the recent mechanistic insights into the antidiabetic effects of the PPARβ/δ-AMPK pathway, including the upregulation of glucose uptake, muscle remodeling, enhanced fatty acid oxidation, and autophagy, as well as the inhibition of endoplasmic reticulum stress and inflammation. A better understanding of the mechanisms underlying the effects resulting from the PPARβ/δ-AMPK pathway may provide the basis for the development of new therapies in the prevention and treatment of insulin resistance and type 2 diabetes mellitus.

Redox signaling in heart failure and therapeutic implications

Heart failure is a growing health burden worldwide characterized by alterations in excitation-contraction coupling, cardiac energetic deficit and oxidative stress. While current treatments are mostly limited to antagonization of neuroendocrine activation, more recent data suggest that also targeting metabolism may provide substantial prognostic benefit. However, although in a broad spectrum of preclinical models, oxidative stress plays a causal role for the development and progression of heart failure, no treatment that targets reactive oxygen species (ROS) directly has entered the clinical arena yet. In the heart, ROS derive from various sources, such as NADPH oxidases, xanthine oxidase, uncoupled nitric oxide synthase and mitochondria. While mitochondria are the primary source of ROS in the heart, communication between different ROS sources may be relevant for physiological signalling events as well as pathologically elevated ROS that deteriorate excitation-contraction coupling, induce hypertrophy and/or trigger cell death. Here, we review the sources of ROS in the heart, the modes of pathological activation of ROS formation as well as therapeutic approaches that may target ROS specifically in mitochondria.

Myocardial Tissue Characterization in Heart Failure with Preserved Ejection Fraction: From Histopathology and Cardiac Magnetic Resonance Findings to Therapeutic Targets

Heart failure with preserved ejection fraction (HFpEF) is a complex clinical syndrome responsible for high mortality and morbidity rates. It has an ever growing social and economic impact and a deeper knowledge of molecular and pathophysiological basis is essential for the ideal management of HFpEF patients. The association between HFpEF and traditional cardiovascular risk factors is known. However, myocardial alterations, as well as pathophysiological mechanisms involved are not completely defined. Under the definition of HFpEF there is a wide spectrum of different myocardial structural alterations. Myocardial hypertrophy and fibrosis, coronary microvascular dysfunction, oxidative stress and inflammation are only some of the main pathological detectable processes. Furthermore, there is a lack of effective pharmacological targets to improve HFpEF patients' outcomes and risk factors control is the primary and unique approach to treat those patients. Myocardial tissue characterization, through invasive and non-invasive techniques, such as endomyocardial biopsy and cardiac magnetic resonance respectively, may represent the starting point to understand the genetic, molecular and pathophysiological mechanisms underlying this complex syndrome. The correlation between histopathological findings and imaging aspects may be the future challenge for the earlier and large-scale HFpEF diagnosis, in order to plan a specific and effective treatment able to modify the disease's natural course.

Heart failure with preserved ejection fraction based on aging and comorbidities

Heart failure (HF) with preserved ejection fraction (HFpEF) is a leading cause of hospitalizations and mortality when diagnosed at the age of ≥ 65 years. HFpEF represents multifactorial and multisystemic syndrome and has different pathophysiology and phenotypes. Its diagnosis is difficult to be established based on left ventricular ejection fraction and may benefit from individually tailored approaches, underlying age-related changes and frequent comorbidities. Compared with the rapid development in the treatment of heart failure with reduced ejection fraction, HFpEF presents a great challenge and needs to be addressed considering the failure of HF drugs to improve its outcomes. Further extensive studies on the relationships between HFpEF, aging, and comorbidities in carefully phenotyped HFpEF subgroups may help understand the biology, diagnosis, and treatment of HFpEF. The current review summarized the diagnostic and therapeutic development of HFpEF based on the complex relationships between aging, comorbidities, and HFpEF.

Compared Impact of Diabetes on the Risk of Heart Failure from Acute Myocardial Infarction to Chronic Coronary Artery Disease

AIM

. - We attempted to describe the risk of heart failure (HF) occurrence according to diabetes mellitus (DM) status in patients with coronary artery disease (CAD) over time, from acute myocardial infarction (MI) to the chronic stable phase.

METHODS

. - For the acute and subacute MI phases, we analysed the FAST-MI cohort restricted to patients without history of HF (n=12,473). The analysis on 1-year outcomes after MI was further restricted to patients who were discharged alive and without history of HF and/or HF symptoms during the index hospitalisation for MI (n=9,181). To analyse the chronic phase, we analysed the CORONOR cohort restricted to patients without history of HF (n=3,871). The primary endpoint was HF occurrence according to DM status. We also analysed the composite of all-cause death or HF.

RESULTS

. - Killip-Kimball class ≥II during the index MI hospitalisation was more frequent in DM patients compared to non-DM patients (29% vs. 15.3%, adjusted OR=1.60). At one year after MI, hospitalisation for HF was more frequent in DM patients (3.3% vs. 1.2%, adjusted HR=1.73). At the chronic phase (5-year outcomes), hospitalisation for HF was more frequent in DM patients (8.5% vs. 4.3%, adjusted HR=1.70). Results focusing on the composite endpoint (all-cause death or HF) were consistent.

CONCLUSION

. - DM was associated with a very constant near 2-fold increase in the risk of HF whatever the presentation of CAD. Avoiding the risk of HF occurrence in CAD patients with DM is critical in daily practice and should be a constant life-long endeavour.

Effects of platelet rich plasma on experimentally induced diabetic heart injury

Diabetic heart is one of the common complications of diabetes mellitus. Platelet-rich plasma (PRP) is an autologous product rich in growth factors that can enhance tissue regeneration. This work was conducted to study the PRP ability to improve diabetes-inducing cardiac changes. Also, it sheds more light on the possible mechanisms through which PRP induces its effects. Rats were divided into; control, PRP, diabetic, and PRP-diabetic groups. Cardiac specimens were obtained and processed for biochemical, histological, and immunohistochemical study. The diabetic group exhibited a significant increase in cardiac oxidative stress, inflammation, and cardiac injury markers if compared with the control group. Additionally, the cardiac tissue showed variable morphological changes in the form of focal distortion and loss of cardiac myocytes. Distorted mitochondria and heterochromatic nuclei were observed in the cardiac muscle fibers. The mean number of charcoal-stained macrophages, and mean area fraction for collagen fibers, mean number of PCNA-immune positive cardiac muscle were significantly decrease in PRP- diabetic group. Collectively, the results showed that PRP treatment ameliorated most of all these previous changes. CONCLUSION: PRP ameliorated the diabetic cardiac injury via inhibition of oxidative stress and inflammation. It was confirmed by biochemical, histological, and immunohistochemical study. It could be concluded that PRP could be used as a potential therapy for diabetic heart.

The Diabetic Cardiomyopathy: The Contributing Pathophysiological Mechanisms

Individuals with diabetes mellitus (DM) disclose a higher incidence and a poorer prognosis of heart failure (HF) than non-diabetic people, even in the absence of other HF risk factors. The adverse impact of diabetes on HF likely reflects an underlying “diabetic cardiomyopathy” (DM–CMP), which may by exacerbated by left ventricular hypertrophy and coronary artery disease (CAD). The pathogenesis of DM-CMP has been a hot topic of research since its first description and is still under active investigation, as a complex interplay among multiple mechanisms may play a role at systemic, myocardial, and cellular/molecular levels. Among these, metabolic abnormalities such as lipotoxicity and glucotoxicity, mitochondrial damage and dysfunction, oxidative stress, abnormal calcium signaling, inflammation, epigenetic factors, and others. These disturbances predispose the diabetic heart to extracellular remodeling and hypertrophy, thus leading to left ventricular diastolic and systolic dysfunction. This Review aims to outline the major pathophysiological changes and the underlying mechanisms leading to myocardial remodeling and cardiac functional derangement in DM-CMP.

Suppression of Inflammatory Cardiac Cytokine Network in Rats with Untreated Obesity and Pre-Diabetes by AT2 Receptor Agonist NP-6A4

Obesity affects over 42% of the United States population and exacerbates heart disease, the leading cause of death in men and women. Obesity also increases pro-inflammatory cytokines that cause chronic tissue damage to vital organs. The standard-of-care does not sufficiently attenuate these inflammatory sequelae. Angiotensin II receptor AT2R is an anti-inflammatory and cardiovascular protective molecule; however, AT2R agonists are not used in the clinic to treat heart disease. NP-6A4 is a new AT2R peptide agonist with an FDA orphan drug designation for pediatric cardiomyopathy. NP-6A4 increases AT2R expression (mRNA and protein) and nitric oxide generation in human cardiovascular cells. AT2R-antagonist PD123319 and AT2RSiRNA suppress NP-6A4-effects indicating that NP-6A4 acts through AT2R. To determine whether NP-6A4 would mitigate cardiac damage from chronic inflammation induced by untreated obesity, we investigated the effects of 2-weeks NP-6A4 treatment (1.8 mg/kg delivered subcutaneously) on cardiac pathology of male Zucker obese (ZO) rats that display obesity, pre-diabetes and cardiac dysfunction. NP-6A4 attenuated cardiac diastolic and systolic dysfunction, cardiac fibrosis and cardiomyocyte hypertrophy, but increased myocardial capillary density. NP-6A4 treatment suppressed tubulointerstitial injury marker urinary β-NAG, and liver injury marker alkaline phosphatase in serum. These protective effects of NP-6A4 occurred in the presence of obesity, hyperinsulinemia, hyperglycemia, and hyperlipidemia, and without modulating blood pressure. NP-6A4 increased expression of AT2R (consistent with human cells) and cardioprotective erythropoietin (EPO) and Notch1 in ZO rat heart, but suppressed nineteen inflammatory cytokines. Cardiac miRNA profiling and in silico analysis showed that NP-6A4 activated a unique miRNA network that may regulate expression of AT2R, EPO, Notch1 and inflammatory cytokines, and mitigate cardiac pathology. Seventeen pro-inflammatory and pro-fibrotic cytokines that increase during lethal cytokine storms caused by infections such as COVID-19 were among the cytokines suppressed by NP-6A4 treatment in ZO rat heart. Thus, NP-6A4 activates a novel anti-inflammatory network comprised of 21 proteins in the heart that was not reported previously. Since NP-6A4's unique mode of action suppresses pro-inflammatory cytokine network and attenuates myocardial damage, it can be an ideal adjuvant drug with other anti-glycemic, anti-hypertensive, standard-of-care drugs to protect the heart tissues from pro-inflammatory and pro-fibrotic cytokine attack induced by obesity.

Sodium-glucose co-transporter 2 inhibitor therapy: mechanisms of action in heart failure

Patients with type 2 diabetes mellitus are at a higher risk of developing heart failure compared with the healthy population. In recent landmark clinical trials, sodium-glucose co-transporter 2 (SGLT2) inhibitor therapies improve blood glucose control and also reduce cardiovascular events and heart failure hospitalisations in patients with type 2 diabetes. Intriguingly, such clinical benefits have also been seen in patients with heart failure in the absence of type 2 diabetes although the underlying mechanisms are not clearly understood. Potential pathways include improved glycaemic control, diuresis, weight reduction and reduction in blood pressure, but none fully explain the observed improvements in clinical outcomes. More recently, novel mechanisms have been proposed to explain these benefits that include improved cardiomyocyte calcium handling, enhanced myocardial energetics, induced autophagy and reduced epicardial fat. We provide an up-to-date review of cardiac-specific SGLT2 inhibitor-mediated mechanisms and highlight studies currently underway investigating some of the proposed mechanisms of action in cardiovascular health and disease.

The Role of Essential Oils and Their Main Compounds in the Management of Cardiovascular Disease Risk Factors

Cardiovascular diseases (CVDs) are a global health burden that greatly impact patient quality of life and account for a huge number of deaths worldwide. Despite current therapies, several side effects have been reported that compromise patient adherence; thus, affecting therapeutic benefits. In this context, plant metabolites, namely volatile extracts and compounds, have emerged as promising therapeutic agents. Indeed, these compounds, in addition to having beneficial bioactivities, are generally more amenable and present less side effects, allowing better patient tolerance. The present review is an updated compilation of the studies carried out in the last 20 years on the beneficial potential of essential oils, and their compounds, against major risk factors of CVDs. Overall, these metabolites show beneficial potential through a direct effect on these risk factors, namely hypertension, dyslipidemia and diabetes, or by acting on related targets, or exerting general cellular protection. In general, monoterpenic compounds are the most studied regarding hypotensive and anti-dyslipidemic/antidiabetic properties, whereas phenylpropanoids are very effective at avoiding platelet aggregation. Despite the number of studies performed, clinical trials are sparse and several aspects related to essential oil’s features, namely volatility and chemical variability, need to be considered in order to guarantee their efficacy in a clinical setting.

Therapeutic potential of targeting oxidative stress in diabetic cardiomyopathy

Even in the absence of coronary artery disease and hypertension, diabetes mellitus (DM) may increase the risk for heart failure development. This risk evolves from functional and structural alterations induced by diabetes in the heart, a cardiac entity termed diabetic cardiomyopathy (DbCM). Oxidative stress, defined as the imbalance of reactive oxygen species (ROS) has been increasingly proposed to contribute to the development of DbCM. There are several sources of ROS production including the mitochondria, NAD(P)H oxidase, xanthine oxidase, and uncoupled nitric oxide synthase. Overproduction of ROS in DbCM is thought to be counterbalanced by elevated antioxidant defense enzymes such as catalase and superoxide dismutase. Excess ROS in the cardiomyocyte results in further ROS production, mitochondrial DNA damage, lipid peroxidation, post-translational modifications of proteins and ultimately cell death and cardiac dysfunction. Furthermore, ROS modulates transcription factors responsible for expression of antioxidant enzymes. Lastly, evidence exists that several pharmacological agents may convey cardiovascular benefit by antioxidant mechanisms. As such, increasing our understanding of the pathways that lead to increased ROS production and impaired antioxidant defense may enable the development of therapeutic strategies against the progression of DbCM. Herein, we review the current knowledge about causes and consequences of ROS in DbCM, as well as the therapeutic potential and strategies of targeting oxidative stress in the diabetic heart.

Medical treatment of heart failure with reduced ejection fraction: the dawn of a new era of personalized treatment?

Recent trials have shown the efficacy of new drugs for the medical therapy of heart failure and reduced ejection fraction (HFrEF). Sodium-glucose cotransporter 2 inhibitors (SGLT2i) reduced hospitalizations for HF, HF events, and cardiovascular death in patients with HFrEF or hospitalized for HF. Iron repletion with ferric carboxymaltose (FCM) improved symptoms, functional capacity, and quality of life in chronic HFrEF patients, and decreased the risk of subsequent HF hospitalizations in subjects with acutely decompensated HF. New-generation potassium binders may allow initiation and up-titration of renin-angiotensin-aldosterone system inhibitors (RASi). Lastly, the guanylate cyclase stimulator vericiguat and the myosin activator omecamtiv mecarbil reduced the primary endpoint in two major controlled trials. These results open novel pathways for the treatment of HFrEF. This review discusses new opportunities of an individualized approach to HFrEF pharmacotherapy, where new compounds expand a spectrum of drugs that target primarily neuroendocrine activation. SGLT2i can be safely applied once daily at a fixed dose to the vast majority of patients with HFrEF, including those with moderate renal dysfunction and/or systolic blood pressure as low as 95-100 mmHg. Additional medications are suitable for more specific phenotypes, with ivabradine providing benefit in patients with sinus rhythm and heart rates ≥70 beats per minute, FCM in the presence of iron deficiency, and potassium-lowering agents to implement RASi when hyperkalaemia occurs. Vericiguat and omecamtiv mecarbil also have potential for tailored approaches towards the hemodynamic status. Thus, a new era is starting for a more personalized medical treatment of HFrEF.

Management of Patients with Chronic Heart Failure and Diabetes Mellitus

Chronic heart failure (CHF) occurs in 4.3-28% of patients with diabetes mellitus and is most often associated with the presence of coronary heart disease, arterial hypertension and the direct adverse effects of insulin-resistance, hyperinsulinemia and hyperglycemia on the myocardium. Diabetes mellitus occurs in 12-47% of patients with CHF and can develop within several years after a diagnosis of HF in 22% of patients due to insulin-resistance of failure tissues. The presence of diabetes mellitus leads to a greater severity of clinical symptoms and hospitalization rate, worsening of quality of life and prognosis in CHF. A decreased left ventricular ejection fraction is an independent predictor of the poor prognosis in the patients with diabetes mellitus. The algorithm of the treatment of CHF in the patients with and without diabetes mellitus is not fundamentally different, but it requires taking into account the metabolic effects of the prescribed drugs. Angiotensin receptor-neprilysin inhibitor are increasingly used in clinical practice and are gradually replacing angiotensin-converting enzyme inhibitors and sartans in CHF both without diabetes mellitus and in its presence. Recently, the effectiveness of type 2 sodium glucose cotransporter inhibitors has been proven in patients with CHF with and without diabetes mellitus. This review is devoted to the relationship of diabetes mellitus and CHF, as well as the approaches to the management of such comorbid patients.

Comparison of clinical outcomes and left ventricular remodeling after ST-elevation myocardial infarction between patients with and without diabetes mellitus

Left ventricular remodeling (LVR) after ST-elevation myocardial infarction (STEMI) is generally thought to be an adaptive but compromising phenomenon particularly in patients with diabetes mellitus (DM). However, whether the extent of LVR is associated with poor prognostic outcome with or without DM after STEMI in the modern era of reperfusion therapy has not been elucidated. This was a single-center retrospective observational study. Altogether, 243 patients who were diagnosed as having STEMI between January 2016 and March 2019, and examined with echocardiography at baseline (at the time of index admission) and mid-term (from 6 to 11 months after index admission) follow-up were included and divided into the DM (n = 98) and non-DM groups (n = 145). The primary outcome was major adverse cardiovascular events (MACEs) defined as the composite of all-cause death, heart failure (HF) hospitalization, and non-fatal myocardial infarction. The median follow-up duration was 621 days (interquartile range: 304–963 days). The DM group was significantly increased the rate of MACEs (P = 0.020) and HF hospitalization (P = 0.037) compared with the non-DM group, despite of less LVR. Multivariate Cox regression analyses revealed that the patients with DM after STEMI were significantly associated with MACEs (Hazard ratio [HR] 2.79, 95% confidence interval [CI] 1.20–6.47, P = 0.017) and HF hospitalization (HR 3.62, 95% CI 1.19–11.02, P = 0.023) after controlling known clinical risk factors. LVR were also significantly associated with MACEs (HR 2.44, 95% CI 1.03–5.78, P = 0.044) and HF hospitalization (HR 3.76, 95% CI 1.15–12.32, P = 0.029). The patients with both DM and LVR had worse clinical outcomes including MACEs and HF hospitalization, suggesting that it is particularly critical to minimize LVR after STEMI in patients with DM.

Amylin deposition activates HIF1α and 6-phosphofructo-2-kinase/fructose-2, 6-biphosphatase 3 (PFKFB3) signaling in failing hearts of non-human primates

Hyperamylinemia induces amylin aggregation and toxicity in the pancreas and contributes to the development of type-2 diabetes (T2D). Cardiac amylin deposition in patients with obesity and T2D was found to accelerate heart dysfunction. Non-human primates (NHPs) have similar genetic, metabolic, and cardiovascular processes as humans. However, the underlying mechanisms of cardiac amylin in NHPs, particularly related to the hypoxia inducible factor (HIF)1α and 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) signaling pathways, are unknown. Here, we demonstrate that in NHPs, amylin deposition in heart failure (HF) contributes to cardiac dysfunction via activation of HIF1α and PFKFB3 signaling. This was confirmed in two in vitro cardiomyocyte models. Furthermore, alterations of intracellular Ca2+, reactive oxygen species, mitochondrial function, and lactate levels were observed in amylin-treated cells. Our study demonstrates a pathological role for amylin in the activation of HIF1α and PFKFB3 signaling in NHPs with HF, establishing amylin as a promising target for heart disease patients.

Immuno-metabolic interfaces in cardiac disease and failure

The interplay between the cardiovascular system, metabolism, and inflammation plays a central role in the pathophysiology of a wide spectrum of cardiovascular diseases, including heart failure. Here, we provide an overview of the fundamental aspects of the interrelation between inflammation and metabolism, ranging from the role of metabolism in immune cell function to the processes how inflammation modulates systemic and cardiac metabolism. Furthermore, we discuss how disruption of this immuno-metabolic interface is involved in the development and progression of cardiovascular disease, with a special focus on heart failure. Finally, we present new technologies and therapeutic approaches that have recently emerged and hold promise for the future of cardiovascular medicine.

Myocardial ketone body utilization in patients with heart failure: The impact of oral ketone ester

AIMS

Upregulation of ketone body (β-hydroxybutyrate, βHB) utilization has been documented in human end-stage heart failure (HF), but is unclear if this is due to intrinsic cardiac metabolic remodeling or a HF-related catabolic state. This study sought to evaluate the maximal ketone body utilization capacity and its determinants in controls and in patients with moderate HF and reduced ejection fraction (HFrEF).

METHODS AND RESULTS

19 HFrEF patients and 9 controls underwent sampling from the arterial circulation (A) and coronary sinus (CS) to measure transmyocardial extraction of energy-providing substrates and oxygen. In a separate experiment, measurements were performed 80-min after oral administration of 25 g of ketone ester (KE, (R)-3-hydroxybutyl(R)-3-hydroxybutyrate) drink in 11 HFrEF and 6 control subjects. There were no statistically significant differences in fasting substrate levels and fractional extractions between HF and controls. Administration of KE increased βHB by 12.9-fold, revealing an increased ability to utilize ketones in HFrEF as compared to controls (fractional extraction, FE%: 52 vs 39%, p = 0.035). βHB FE% correlated directly with βHB myocardial delivery (r = 0.90), LV mass (r = 0.56), LV diameter (r = 0.65) and inversely with LV EF (-0.59) (all p < 0.05). βHB FE% positively correlated with lactate FE% (p < 0.01), but not with FFA or glucose FE%, arguing against substrate competition.

CONCLUSIONS

Acute nutritional ketosis enhances βHB extraction in patients with HFrEF compared to controls, and this enhancement correlates with degree of cardiac dysfunction and remodeling. Data suggest that subclinical metabolic remodeling occurs early in HF progression. Further studies are needed to determine whether exogenous ketones may have a potential therapeutic role.

Mitochondrial Ca2+, redox environment and ROS emission in heart failure: Two sides of the same coin?

Heart failure (HF) is a progressive, debilitating condition characterized, in part, by altered ionic equilibria, increased ROS production and impaired cellular energy metabolism, contributing to variable profiles of systolic and diastolic dysfunction with significant functional limitations and risk of premature death. We summarize current knowledge concerning changes of intracellular Na+ and Ca2+ control mechanisms during the disease progression and their consequences on mitochondrial Ca2+ homeostasis and the shift in redox balance. Absent existing biological data, our computational modeling studies advance a new 'in silico' analysis to reconcile existing opposing views, based on different experimental HF models, regarding variations in mitochondrial Ca2+ concentration that participate in triggering and perpetuating oxidative stress in the failing heart and their impact on cardiac energetics. In agreement with our hypothesis and the literature, model simulations demonstrate the possibility that the heart's redox status together with cytoplasmic Na+ concentrations act as regulators of mitochondrial Ca2+ levels in HF and of the bioenergetics response that will ultimately drive ATP supply and oxidative stress. The resulting model predictions propose future directions to study the evolution of HF as well as other types of heart disease, and to develop novel testable mechanistic hypotheses that may lead to improved therapeutics.

Cardioprotective mechanism of SGLT2 inhibitor against myocardial infarction is through reduction of autosis

Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce cardiovascular mortality in patients with diabetes mellitus but the protective mechanism remains elusive. Here we demonstrated that the SGLT2 inhibitor, Empagliflozin (EMPA), suppresses cardiomyocytes autosis (autophagic cell death) to confer cardioprotective effects. Using myocardial infarction (MI) mouse models with and without diabetes mellitus, EMPA treatment significantly reduced infarct size, and myocardial fibrosis, thereby leading to improved cardiac function and survival. In the context of ischemia and nutritional glucose deprivation where autosis is already highly stimulated, EMPA directly inhibits the activity of the Na⁺/H⁺ exchanger 1 (NHE1) in the cardiomyocytes to regulate excessive autophagy. Knockdown of NHE1 significantly rescued glucose deprivation-induced autosis. In contrast, overexpression of NHE1 aggravated the cardiomyocytes death in response to starvation, which was effectively rescued by EMPA treatment. Furthermore, in vitro and in vivo analysis of NHE1 and Beclin 1 knockout mice validated that EMPA’s cardioprotective effects are at least in part through downregulation of autophagic flux. These findings provide new insights for drug development, specifically targeting NHE1 and autosis for ventricular remodeling and heart failure after MI in both diabetic and non-diabetic patients.

Mechanisms underlying the pathophysiology of heart failure with preserved ejection fraction: the tip of the iceberg

Heart failure with preserved ejection fraction (HFpEF) is a multifaceted syndrome with a complex aetiology often associated with several comorbidities, such as left ventricle pressure overload, diabetes mellitus, obesity, and kidney disease. Its pathophysiology remains obscure mainly due to the complex phenotype induced by all these associated comorbidities and to the scarcity of animal models that adequately mimic HFpEF. Increased oxidative stress, inflammation, and endothelial dysfunction are currently accepted as key players in HFpEF pathophysiology. However, we have just started to unveil HFpEF complexity and the role of calcium handling, energetic metabolism, and mitochondrial function remain to clarify. Indeed, the enlightenment of such cellular and molecular mechanisms represents an opportunity to develop novel therapeutic approaches and thus to improve HFpEF treatment options. In the last decades, the number of research groups dedicated to studying HFpEF has increased, denoting the importance and the magnitude achieved by this syndrome. In the current technological and web world, the amount of information is overwhelming, driving us not only to compile the most relevant information about the theme but also to explore beyond the tip of the iceberg. Thus, this review aims to encompass the most recent knowledge related to HFpEF or HFpEF-associated comorbidities, focusing mainly on myocardial metabolism, oxidative stress, and energetic pathways.

[Diagnosis, Prevention and Treatment of Cardiovascular Disease in People with Diabetes and Prediabetes]

Diagnosis, Prevention and Treatment of Cardiovascular Disease in People with Diabetes and Prediabetes Abstract. Diabetes is associated with an increased cardiovascular risk. In addition to optimizing glycemia, timely diagnosis and stringent control of cardiovascular risk factors is essential for individuals with diabetes. Therapeutic options include lifestyle-optimization, individualized drug therapy and targeted treatment of concomitant or secondary cardiovascular disease. Cardiovascular disease occurs more often in individuals with diabetes and includes heart failure, atrial fibrillation, coronary heart disease and sudden cardiac death. The correct choice of antidiabetic drugs and interventions can control cardiovascular risk factors, reduce cardiovascular risk and treat concomitant or secondary diseases in a targeted manner. This review is intended to provide guidance on diagnosis, treatment and choice of therapy for individuals with type 2 diabetes without and with concomitant or secondary cardiovascular disease.

Role of AMP-activated protein kinase on cardio-metabolic abnormalities in the development of diabetic cardiomyopathy: A molecular landscape

Cardiovascular complications associated with diabetes mellitus remains a leading cause of morbidity and mortality across the world. Diabetic cardiomyopathy is a descriptive pathology that in absence of co-morbidities such as hypertension, dyslipidemia initially characterized by cardiac stiffness, myocardial fibrosis, ventricular hypertrophy, and remodeling. These abnormalities further contribute to diastolic dysfunctions followed by systolic dysfunctions and eventually results in clinical heart failure (HF). The clinical outcomes associated with HF are considerably worse in patients with diabetes. The complexity of the pathogenesis and clinical features of diabetic cardiomyopathy raises serious questions in developing a therapeutic strategy to manage cardio-metabolic abnormalities. Despite extensive research in the past decade the compelling approaches to manage and treat diabetic cardiomyopathy are limited. AMP-Activated Protein Kinase (AMPK), a serine-threonine kinase, often referred to as cellular "metabolic master switch". During the development and progression of diabetic cardiomyopathy, a plethora of evidence demonstrate the beneficial role of AMPK on cardio-metabolic abnormalities including altered substrate utilization, impaired cardiac insulin metabolic signaling, mitochondrial dysfunction and oxidative stress, myocardial inflammation, increased accumulation of advanced glycation end-products, impaired cardiac calcium handling, maladaptive activation of the renin-angiotensin-aldosterone system, endoplasmic reticulum stress, myocardial fibrosis, ventricular hypertrophy, cardiac apoptosis, and impaired autophagy. Therefore, in this review, we have summarized the findings from pre-clinical and clinical studies and provided a collective overview of the pathophysiological mechanism and the regulatory role of AMPK on cardio-metabolic abnormalities during the development of diabetic cardiomyopathy.

How Diabetes and Heart Failure Modulate Each Other and Condition Management

Heart failure (HF) and diabetes mellitus (DM) confer considerable burden on the health care system. Although these often occur together, DM can increase risk of HF, whereas HF can accelerate complications of DM. HF is a clinical syndrome resulting from systolic or diastolic impairment caused by ischemic, nonischemic (eg, DM), or other etiologies. HF exists along a spectrum from stage A (ie, persons at risk of DM) to stage D (ie, refractory HF from end-stage DM cardiomyopathy [DMCM]). HF is further categorized by reduced, midrange, and preserved ejection fraction (EF). In type 2 DM, the most prevalent form of DM, several pathophysiological mechanisms (eg, insulin resistance and hyperglycemia) can contribute to myocardial damage, leading to DMCM. Management of HF and DM and patient outcomes are guided by EF and drug efficacy. In this review, we focus on the interplay between HF and DM on disease pathophysiology, management, and patient outcomes. Specifically, we highlight the role of novel antihyperglycemic (eg, sodium glucose cotransporter 2 inhibitors) and HF therapies (eg, renin-angiotensin-aldosterone system inhibitors) on HF outcomes in patients with DM and HF.

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.

Heart failure and diabetes: role of ATM

Heart failure is a leading cause of death in the United States. Diabetes, also known as diabetes mellitus (DM), exponentially increases the risk of heart failure. The increase in oxidative stress and metabolic dysfunction caused by DM can lead to DNA damage and the development of diabetic cardiomyopathy. Ataxia telangiectasia mutated kinase (ATM) is a DNA damage response protein with a primary nuclear function to regulate cell cycle progression in response to double-strand DNA breaks, acts as a redox sensor, and facilitates DNA repair. ATM deficiency associates with the development of insulin resistance and DM. Consequently, patients with Ataxia telangiectasia, a rare autosomal recessive disorder, have an increased risk of developing heart failure. The main objective of this review is to summarize the shared metabolic and cardiac abnormalities associated with DM and ATM deficiency, with a focus on the development of heart failure.

Metformin: still the sweet spot for CV protection in diabetes?

Metformin remains the first-line drug treatment for type 2 diabetes (T2D) in most guidelines not only because it achieves significant reduction in HbA1c but also because of a wealth of clinical experience regarding its safety and observational data that has shown that metformin use is associated with lower mortality rates when compared to sulphonylureas or insulin. Recently other diabetes drugs, particularly SGLT2 inhibitors (SGLT2i) and GLP1 receptor agonists (GLP1RA), have attracted considerable attention for their cardioprotective benefits reported in cardiovascular outcome trials (CVOTs). Randomised control trials on these newer drugs are on a larger scale but have shorter follow-up than UKPDS, the main study supporting metformin use. In a recent change to the European Society of Cardiology guidelines, metformin was replaced by SGLT2i and GLP1RA as first-line for T2D with atherosclerotic cardiovascular disease, whereas American Diabetes Association and UK-wide guidelines maintain metformin as first choice drug pharmacotherapy for all T2D. A definitive evidence-base for prioritisation of these drugs is currently missing because there are no head-to-head clinical trial data. Without such trials being forthcoming, innovative, pragmatic and low-cost 'real-world' trial approaches based on electronic health records may need to be harnessed to determine the correct priority, combinations of drugs and/or identify-specific patient populations most likely to benefit from each one.

Sodium-Glucose Co-transporter 2 Inhibitors in the Failing Heart: a Growing Potential

Sodium-glucose co-transporter 2 inhibitors (SGLT2i) are a new drug class designed to treat patients with type 2 diabetes (T2D). However, cardiovascular outcome trials showed that SGLT2i also offer protection against heart failure (HF)-related events and cardiovascular mortality. These benefits appear to be independent of glycaemic control and have recently been demonstrated in the HF population with reduced ejection fraction (HFrEF), with or without T2D. This comprehensive, evidence-based review focuses on the published studies concerning HF outcomes with SGLT2i, discussing issues that may underlie the different results, along with the impact of these new drugs in clinical practice. The potential translational mechanisms behind SGLT2i cardio-renal benefits and the information that ongoing studies may add to the already existing body of evidence are also reviewed. Finally, we focus on practical management issues regarding SGLT2i use in association with other T2D and HFrEF common pharmacological therapies. Safety considerations are also highlighted. Considering the paradigm shift in T2D management, from a focus on glycaemic control to a broader approach on cardiovascular protection and event reduction, including the potential for wide SGLT2i implementation in HF patients, with or without T2D, we are facing a promising time for major changes in the global management of cardiovascular disease.

The Vicious Circle of Left Ventricular Dysfunction and Diabetes: From Pathophysiology to Emerging Treatments

CONTEXT

Diabetes and heart failure (HF) are 2 deadly and strictly related epidemic disorders. The aim of this review is to present an updated discussion of the epidemiology, pathophysiology, clinical presentation and treatment options for HF in diabetes.

EVIDENCE ACQUISITION

Relevant references published up to February 2020 were identified through searches in PubMed. Quality was graded using the Newcastle-Ottawa score in observational studies and the Cochrane Collaboration tool in randomized studies.

EVIDENCE SYNTHESIS

Metabolic and neurohumoral derangements, oxidative stress, inflammation, micro- and macroangiopathy all contribute through complex molecular and cellular mechanisms to cardiac dysfunction in diabetes, which in turn, results as one the most frequent underlying conditions affecting up to 42% of patients with HF and causing a 34% increased risk of cardiovascular death. On top of traditional guideline-based HF medical and device therapies, equally effective in patients with and without diabetes, a new class of glucose-lowering agents acting through the sodium-glucose cotransporter 2 (SGLT2) inhibition showed impressive results in reducing HF outcomes in individuals with diabetes and represents an active area of investigation.

CONCLUSIONS

Diabetes and HF are strictly linked in a bidirectional and deadly vicious circle difficult to break. Therefore, preventive strategies and a timely diagnosis are crucial to improve outcomes in such patients. SGLT2 inhibitors represent a major breakthrough with remarkably consistent findings. However, it is still not clear whether their benefits may be definitely extended to patients with HF with preserved ejection fraction, to those without diabetes and in the acute setting.

Mechanisms of diabetic cardiomyopathy and potential therapeutic strategies: preclinical and clinical evidence

The pathogenesis and clinical features of diabetic cardiomyopathy have been well-studied in the past decade, but effective approaches to prevent and treat this disease are limited. Diabetic cardiomyopathy occurs as a result of the dysregulated glucose and lipid metabolism associated with diabetes mellitus, which leads to increased oxidative stress and the activation of multiple inflammatory pathways that mediate cellular and extracellular injury, pathological cardiac remodelling, and diastolic and systolic dysfunction. Preclinical studies in animal models of diabetes have identified multiple intracellular pathways involved in the pathogenesis of diabetic cardiomyopathy and potential cardioprotective strategies to prevent and treat the disease, including antifibrotic agents, anti-inflammatory agents and antioxidants. Some of these interventions have been tested in clinical trials and have shown favourable initial results. In this Review, we discuss the mechanisms underlying the development of diabetic cardiomyopathy and heart failure in type 1 and type 2 diabetes mellitus, and we summarize the evidence from preclinical and clinical studies that might provide guidance for the development of targeted strategies. We also highlight some of the novel pharmacological therapeutic strategies for the treatment and prevention of diabetic cardiomyopathy.