Diabetic cardiomyopathy--fact or fiction? Herz. 2011;36:102-115. [PMID: 21424347 DOI: 10.1007/s00059-011-3429-4]

Diabetic Cardiomyopathy: What Clinicians Should Know

Diabetes has classically been associated with atherosclerotic cardiovascular disease. However, heart failure is now increasingly recognized as a prevalent and often first cardiovascular complication among patients with diabetes. Investigation of this epidemiological relationship has led to recognition of diabetic cardiomyopathy, or structural heart disease that develops in patients with diabetes and may lead to progressive heart failure independently of coronary artery disease or conventional cardiovascular risk factors such as hypertension. Despite increased awareness, clinical management of this common cardiovascular complication remains challenging, with no consensus on its diagnosis or treatment. The lack of specific therapy has been recognized as an unmet clinical need. In this review, we summarize current understanding of the hallmark metabolic and structural changes of diabetic cardiomyopathy, appraise current tools for diagnosis and staging among patients, and describe the emerging but still preclinical data on therapeutic options.

Impact of Sex and Diabetes in Patients with Heart Failure

PURPOSE OF REVIEW

Heart failure (HF) is a complex clinical syndrome with a growing global health burden. This review explores the intersection of HF, diabetes mellitus, and sex, highlighting epidemiological patterns, pathophysiological mechanisms, and treatment implications.

RECENT FINDINGS

Despite similar HF prevalence in men and women, diabetes mellitus (DM) appears to exert a more pronounced impact on HF outcomes in women. Pathophysiological differences involve cardiovascular risk factors, severe left ventricular dysfunction, and coronary artery disease, as well as hormonal influences and inflammatory markers. Diabetic cardiomyopathy introduces a sex-specific challenge, with women experiencing common adverse outcomes related to increased fibrosis and myocardial remodeling. Treatment strategies, particularly sodium-glucose cotransporter 2 inhibitors, exhibit cardiovascular benefits, but their response may differ in women. The link between HF and DM is bidirectional, with diabetes significantly increasing the risk of HF, and vice versa. Additionally, the impact of diabetes on mortality appears more pronounced in women than in men, leading to a modification of the traditional gender gap observed in HF outcomes. A personalized approach is crucial, and further research to improve outcomes in the complex interplay of HF, diabetes, and sex is needed.

Nrf2 signaling in diabetic nephropathy, cardiomyopathy and neuropathy: Therapeutic targeting, challenges and future prospective

Western lifestyle contributes to an overt increase in the prevalence of metabolic anomalies including diabetes mellitus (DM) and obesity. Prevalence of DM is rapidly growing worldwide, affecting many individuals in both developing and developed countries. DM is correlated with the onset and development of complications with diabetic nephropathy (DN), diabetic cardiomyopathy (DC) and diabetic neuropathy being the most devastating pathological events. On the other hand, Nrf2 is a regulator for redox balance in cells and accounts for activation of antioxidant enzymes. Dysregulation of Nrf2 signaling has been shown in various human diseases such as DM. This review focuses on the role Nrf2 signaling in major diabetic complications and targeting Nrf2 for treatment of this disease. These three complications share similarities including the presence of oxidative stress, inflammation and fibrosis. Onset and development of fibrosis impairs organ function, while oxidative stress and inflammation can evoke damage to cells. Activation of Nrf2 signaling significantly dampens inflammation and oxidative damage, and is beneficial in retarding interstitial fibrosis in diabetic complications. SIRT1 and AMPK are among the predominant pathways to upregulate Nrf2 expression in the amelioration of DN, DC and diabetic neuropathy. Moreover, certain therapeutic agents such as resveratrol and curcumin, among others, have been employed in promoting Nrf2 expression to upregulate HO-1 and other antioxidant enzymes in the combat of oxidative stress in the face of DM.

Dynamic evolution and mechanism of myocardial glucose metabolism in different functional phenotypes of diabetic cardiomyopathy - a study based on 18 F-FDG microPET myocardial metabolic imaging

PURPOSE

To use ¹⁸ F-FDG microPET dynamic imaging to preliminarily identify the changes of myocardial glucose metabolism corresponding to different functional phenotypes of diabetic cardiomyopathy (DCM) in mice and elucidate their relationships.

METHODS

Left ventricular function was measured by echocardiography in C57BL/KsJ-db/db (db/db) mice and their controls at 8, 12, 16, and 20 weeks of age to divide DCM stages and functional phenotypes. Myocardial histopathology was used to verify the staging accuracy and list-mode microPET dynamic imaging was conducted. The myocardial metabolic rate of glucose (MRglu) and the glucose uptake rate constant (Ki) were derived via Patlak graphical analysis, and the differences in myocardial glucose metabolism levels in different DCM stages were compared. The key proteins involved in myocardial glucose metabolism signaling pathway were analyzed by Western blotting to elucidate the underlying mechanism of abnormal glucose metabolism in DCM.

RESULTS

Compared with the controls, the ratio of early diastolic transmitral flow velocity to early diastolic mitral annular tissue velocity (E/e') of db/db mice was significantly increased from the age of 12 weeks, while the left ventricular ejection fraction (LVEF) was significantly decreased from the age of 16 weeks (all P < 0.05). Based on the staging criteria, 8 and 12 weeks (8/12w) db/db mice were in DCM stage 1 (diastolic dysfunction with normal LVEF), and 16 and 20 weeks (16/20w) db/db mice were in DCM stage 2/3 (diastolic and systolic dysfunction). The degree of myocardial fibrosis, glycogen deposition and ultrastructural damage in 16/20w db/db mice were more obvious than those in 8/12w group. The myocardial MRglu, Ki of db/db mice in 8/12w group or 16/20w group were significantly lower than those in the control group (all P < 0.05), while the myocardial standard uptake value (SUV) was not significantly reduced in the 8/12w group compared with the control group (P > 0.05). MRglu and SUV were moderately negatively correlated with the E/e' ratio (r=-0.539 and - 0.512, P = 0.007 and 0.011), which were not significantly correlated with LVEF (P > 0.05). Meanwhile, Ki was not significantly correlated with LVEF or E/e' ratio. The decreased expression of glucose transporter (GLUT) -4 in db/db mice preceded GLUT-1 and was accompanied by decreased phosphorylated AMP-activated protein kinase (p-AMPK) expression. Myocardial MRglu, Ki and SUV were significantly positively correlated with the expression of GLUT-4 (MRglu: r = 0.537; Ki: r = 0.818; SUV: r = 0.491; P = 0.000 ~ 0.046), but there was no significant correlation with GLUT-1 expression (P = 0.238 ~ 0.780).

CONCLUSIONS

During the progression of DCM, with the changes of left ventricular functional phenotype, abnormal and dynamic changes of myocardial glucose metabolism can occur in the early stage.

Emerging Therapy for Diabetic Cardiomyopathy: From Molecular Mechanism to Clinical Practice

Diabetic cardiomyopathy is characterized by abnormal myocardial structure or performance in the absence of coronary artery disease or significant valvular heart disease in patients with diabetes mellitus. The spectrum of diabetic cardiomyopathy ranges from subtle myocardial changes to myocardial fibrosis and diastolic function and finally to symptomatic heart failure. Except for sodium–glucose transport protein 2 inhibitors and possibly bariatric and metabolic surgery, there is currently no specific treatment for this distinct disease entity in patients with diabetes. The molecular mechanism of diabetic cardiomyopathy includes impaired nutrient-sensing signaling, dysregulated autophagy, impaired mitochondrial energetics, altered fuel utilization, oxidative stress and lipid peroxidation, advanced glycation end-products, inflammation, impaired calcium homeostasis, abnormal endothelial function and nitric oxide production, aberrant epidermal growth factor receptor signaling, the activation of the renin–angiotensin–aldosterone system and sympathetic hyperactivity, and extracellular matrix accumulation and fibrosis. Here, we summarize several important emerging treatments for diabetic cardiomyopathy targeting specific molecular mechanisms, with evidence from preclinical studies and clinical trials.

Lipoxin and glycation in SREBP signaling: Insight into diabetic cardiomyopathy and associated lipotoxicity

Diabetes and cardiovascular diseases are the leading cause of morbidity and mortality worldwide. Diabetes increases cardiovascular risk through hyperglycemia and atherosclerosis. Chronic hyperglycemia accelerates glycation reaction, which forms advanced glycation end products (AGEs). Additionally, hyperglycemia with enhanced levels of cholesterol, native and oxidized low-density lipoproteins, free fatty acids, and oxidative stress induces lipotoxicity. Accelerated glycation and disturbed lipid metabolism are characteristic features of diabetic heart failure. SREBP signaling plays a significant role in lipid and glucose homeostasis. AGEs increase lipotoxicity in diabetic cardiomyopathy by inhibiting SREBP signaling. While anti-inflammatory lipid mediators, lipoxins resolve inflammation caused by lipotoxicity by upregulating the PPARγ expression and regulating CD36. PPARγ connects the bridge between glycation and lipoxin in SREBP signaling. A summary of treatment modalities against diabetic cardiomyopathy is given in brief. This review indicates the novel therapeutic approach in the crosstalk between glycation and lipoxin in SREBP signaling.

A comparative analysis of conventional and speckle-tracking strain echocardiographic findings in diabetic and non-diabetic kidney disease patients with normal ejection fraction

This study aimed to compare the differences in echocardiographic and strain parameters in patients with diabetic kidney disease (DKD) and non-diabetic kidney disease (NDKD) in a cohort with pre-dialysis chronic kidney disease (CKD) and normal ejection fraction (EF). In this single-center prospective study, patients with CKD stages 3-5 and EF > 55% were included. We compared cardiac structure and function using conventional and speckle-tracking strain echocardiography among DKD and NDKD groups. Cardiovascular outcomes were assessed at the end of the study. Of the included 117 patients, 56 (47.9%) had DKD, and 61 (52.1%) had NDKD. Patients with DKD had higher ratios of early mitral inflow velocity and mitral annular early diastolic velocity (E/e') (11.9 ± 4.4 vs. 9.8 ± 3.5; p = 0.004), lower septal e' velocity (7.1 ± 2.5 vs. 8.2 ± 2.8; p = 0.031), lower lateral e' velocity (9.2 ± 2.9 vs. 10.4 ± 3.8; p = 0.045) and longer deceleration times (209.2 ± 41.5 vs. 189.1 ± 48.0; p = 0.017), compared to those with NDKD. Left ventricular mass index (LVMI), global longitudinal strain (GLS), early diastolic strain rate (SR_E), and E/SR_E were similar. At a median follow-up of 239 days, 3-P MACE (11.5% vs. 4.9%; p = 0.047) and 4-P MACE (28.6% vs. 11.5%; p = 0.020) were observed to be higher in the DKD group. Diastolic dysfunction was more common in patients with DKD, compared to those with NDKD, although both groups had similar LVMI and GLS. Those with DKD also had poorer cardiovascular outcomes. This highlights the importance of the assessment of diastolic function in CKD, particularly in those with diabetic CKD.

Diabetic cardiomyopathy: a brief summary on lipid toxicity

Diabetes mellitus (DM) is a serious epidemic around the globe, and cardiovascular diseases account for the majority of deaths in patients with DM. Diabetic cardiomyopathy (DCM) is defined as a cardiac dysfunction derived from DM without the presence of coronary artery diseases and hypertension. Patients with either type 1 or type 2 DM are at high risk of developing DCM and even heart failure. Metabolic disorders of obesity and insulin resistance in type 2 diabetic environments result in dyslipidaemia and subsequent lipid-induced toxicity (lipotoxicity) in organs including the heart. Although various mechanisms have been proposed underlying DCM, it remains incompletely understood how lipotoxicity alters cardiac function and how DM induces clinical heart syndrome. With recent progress, we here summarize the latest discoveries on lipid-induced cardiac toxicity in diabetic hearts and discuss the underlying therapies and controversies in clinical DCM.

The importance of caveolin as a target in the prevention and treatment of diabetic cardiomyopathy

The diabetic population has been increasing in the past decades and diabetic cardiomyopathy (DCM), a pathology that is defined by the presence of cardiac remodeling and dysfunction without conventional cardiac risk factors such as hypertension and coronary heart diseases, would eventually lead to fatal heart failure in the absence of effective treatment. Impaired insulin signaling, commonly known as insulin resistance, plays an important role in the development of DCM. A family of integral membrane proteins named caveolins (mainly caveolin-1 and caveolin-3 in the myocardium) and a protein hormone adiponectin (APN) have all been shown to be important for maintaining normal insulin signaling. Abnormalities in caveolins and APN have respectively been demonstrated to cause DCM. This review aims to summarize recent research findings of the roles and mechanisms of caveolins and APN in the development of DCM, and also explore the possible interplay between caveolins and APN.

NLRP3 Inflammasome/Pyroptosis: A Key Driving Force in Diabetic Cardiomyopathy

Diabetic cardiomyopathy (DCM), a serious diabetic complication, is a kind of low-grade inflammatory cardiovascular disorder. Due to the high risk of morbidity and mortality, DCM has demanded the attention of medical researchers worldwide. The pathophysiological nature of DCM is intricate, and the genesis and development of which are a consequence of the coaction of many factors. However, the exact pathogenesis mechanism of DCM remains unclear. Pyroptosis is a newly identified programmed cell death (PCD) that is directly related to gasdermin D(GSDMD). It is characterized by pore formation on the cell plasma membrane, the release of inflammatory mediators, and cell lysis. The initiation of pyroptosis is closely correlated with NOD-like receptor 3 (NLRP3) activation, which activates caspase-1 and promotes the cleaving of GSDMD. In addition to adjusting the host’s immune defense, NLRP3 inflammasome/pyroptosis plays a critical role in controlling the systemic inflammatory response. Recent evidence has indicated that NLRP3 inflammasome/pyroptosis has a strong link with DCM. Targeting the activation of NLRP3 inflammasome or pyroptosis may be a hopeful therapeutic strategy for DCM. The focus of this review is to summarize the relevant mechanisms of pyroptosis and the relative contributions in DCM, highlighting the potential therapeutic targets in this field.

The impact of lifestyle intervention on left atrial function in type 2 diabetes: results from the DIASTOLIC study

Aerobic exercise training and low energy diets have been shown to improve left ventricular remodelling and diastolic function in adults with type 2 diabetes (T2D), albeit with differential effects. The impact of these lifestyle interventions on left atrial (LA) function, however, has not previously been reported. The DIASTOLIC study was a prospective, randomised, open-label, blind endpoint trial, in which 90 people with obesity and T2D and no prevalent cardiovascular disease were randomised to a 12-week intervention of: (i) routine care, (ii) aerobic exercise training, or (iii) low energy (≈ 810 kcal/day) meal replacement plan (MRP). Cardiac magnetic resonance (CMR) imaging was performed pre- and post-intervention. Image analysis included LA volumes (LAV), emptying fraction (LAEF), and LA strain (LAS) corresponding to LA reservoir (LAS-r), conduit (LAS-cd), and booster pump (LAS-bp) function. 73 participants with T2D (mean age 50 ± 6 years, 62% male, body mass index (BMI) 36.1 ± 5.3 kg/m2) completed the trial and had analysable LA images. There was no significant change in CMR measured LA volumetric function (LAV/LAEF) in any group. The routine care group showed no significant change in BMI or LAS. In the MRP group, there were significant reductions in BMI (4.5 kg/m2) and a significant increase in LAS-r and LAS-bp (29.9 ± 7.0 to 32.3 ± 7.0%, p = 0.036 and 14.6 ± 5.3 to 17.2 ± 3.7%, p = 0.034). The exercise group showed a small reduction in BMI (0.49 kg/m2), with no significant change in LAS. Compared to routine care, weight loss via a 12-week MRP, led to improvements in LA filling and contractile function in adults with T2D and obesity. However, these within-group changes were not statistically significant on between-group comparison. ClinicalTrials.gov Identifier: NCT02590822.

Echocardiographic phenotypes of Chinese patients with type 2 diabetes may indicate early diabetic myocardial disease

AIM

Type 2 diabetes may impair cardiac structure and function at very early stage, other factors, for example, obesity and hypertension, can induce aforementioned abnormalities individually. This study aimed to explore precise prevention and treatment of diabetic cardiomyopathy (DCM) by using cluster analysis of echocardiographic variables.

METHODS AND RESULTS

A total of 66 536 inpatients with diabetes from 2013 to 2018 were investigated, and 7112 patients were available for analysis after nadir. The cluster analysis was performed on echocardiographic variables to assess the clinical profiles and risk factors of clusters. Two clusters were identified. Cluster 1 with 3576 patients (50.3%, including 62.5% female) had hypertension in 62.4%, while the lower rate of obesity (13.7%). Ultrasound findings showed that 79.9% of them had left ventricular diastolic dysfunction (LVDD), the most characteristic change in the early stages of DCM. Systolic blood pressure (SBP), uric acid and antithrombin III were independent risk factors for LVDD (P < 0.0001); 64.0% of the 3536 patients in the second group were male, with a high prevalence of obesity (30.1%) and a higher prevalence of hypertension (79.5%), In particular, decreased systolic function and a high rate of LV hypertrophy (46.8%) represented the progressive phase of DCM (P < 0.0001). SBP, diastolic blood pressure, BMI and creatinine were independent correlates of LV mass index (P < 0.05).

CONCLUSION

The cluster analysis of echocardiographic variables may improve the identification of groups of patients with similar risks and different disease courses and will facilitate the achievement of targeted early prevention and treatment of DCM.

Pancreatic iron quantification with MR imaging: a practical guide

Accurate determination of pancreatic iron status is crucial for preventing impairment of the exocrine and endocrine function of the pancreas and for prospectively stratifying the cardiac iron risk. The following article should be a sort of practical guide for radiologists interested in quantifying pancreatic iron overload by Magnetic Resonance Imaging (MRI). After a brief background on iron-deposition diseases, we will describe basic principles and relative advantages and disadvantages of the more widely used and clinically feasible MRI-based techniques for pancreatic iron assessment. These methods can be classified into signal intensity ratio (SIR) and relaxometry methods. We will examine different technical aspects representing the key for accurate and precise relaxation time measurement.

Low Carbohydrate Diets for Diabetic Cardiomyopathy: A Hypothesis

Elevated blood glucose levels, insulin resistance (IR), hyperinsulinemia and dyslipidemia the key aspects of type 2 diabetes mellitus (T2DM), contribute to the development of a certain form of cardiomyopathy. This cardiomyopathy, also known as diabetic cardiomyopathy (DMCM), typically occurs in the absence of overt coronary artery disease (CAD), hypertension or valvular disease. DMCM encompasses a variety of pathophysiological processes impacting the myocardium, hence increasing the risk for heart failure (HF) and significantly worsening outcomes in this population. Low fat (LF), calorie-restricted diets have been suggested as the preferred eating pattern for patients with HF. However, LF diets are naturally higher in carbohydrates (CHO). We argue that in an insulin resistant state, such as in DMCM, LF diets may worsen glycaemic control and promote further insulin resistance (IR), contributing to a physiological and functional decline in DMCM. We postulate that CHO restriction targeting hyperinsulinemia may be able to improve tissue and systemic IR. In recent years low carbohydrate diets (LC) including ketogenic diets (KD), have emerged as a safe and effective tool for the management of various clinical conditions such as T2DM and other metabolic disorders. CHO restriction achieves sustained glycaemic control, lower insulin levels and successfully reverses IR. In addition to this, its pleiotropic effects may present a metabolic stress defense and facilitate improvement to cardiac function in patients with HF. We therefore hypothesize that patients who adopt a LC diet may require less medications and experience improvements in HF-related symptom burden.

The multifaceted role of cytochrome P450-Derived arachidonic acid metabolites in diabetes and diabetic cardiomyopathy

Understanding lipid metabolism is a critical key to understanding the pathogenesis of Diabetes Mellitus (DM). It is known that 60-90% of DM patients are obese or used to be obese. The incidence of obesity is rising owing to the modern sedentary lifestyle that leads to insulin resistance and increased levels of free fatty acids, predisposing tissues to utilize more lipids with less glucose uptake. However, the exact mechanism is not yet fully elucidated. Diabetic cardiomyopathy seems to be associated with these alterations in lipid metabolism. Arachidonic acid (AA) is an important fatty acid that is metabolized to several bioactive compounds by cyclooxygenases, lipoxygenases, and the more recently discovered, cytochrome P450 (P450) enzymes. P450 metabolizes AA to either epoxy-AA (EETs) or hydroxy-AA (HETEs). Studies showed that EETs could have cardioprotective effects and beneficial effects in reversing abnormalities in glucose and insulin homeostasis. Conversely, HETEs, most importantly 12-HETE and 20-HETE, were found to interfere with normal glucose and insulin homeostasis and thus, might be involved in diabetic cardiomyopathy. In this review, we highlight the role of P450-derived AA metabolites in the context of DM and diabetic cardiomyopathy and their potential use as a target for developing new treatments for DM and diabetic cardiomyopathy.

[Implementation of a support system for isolated elderly people to limit the consequences of the Covid-19 epidemic in Buenos Aires]

The Covid-19 pandemic with its associated quarantine and isolation has had a dramatic impact on the elderly. In order to mitigate this, the National University of La Plata and the Agence Universitaire de la Francophonie set up a health surveillance and early warning project for the elderly in Buenos Aires, Argentina. This interventional study, has included 1,964 people. A general health and quality of life questionnaire was completed by all participants at the beginning of the isolation, and another time a year later.

Premature ventricular complex site of origin and ablation outcomes in patients with diabetes mellitus

BACKGROUND

Premature ventricular complexes (PVCs) are frequent in patients with diabetes mellitus (DM). Still, the PVCs characteristics as well as the outcomes after catheter ablation in this population remain unknown. Aim of the study was to describe principal features of PVCs ablated in a wide DM-patients cohort and report postablation clinical outcomes in the follow-up of patients with DM and left ventricular dysfunction.

METHODS

From April 2012 to April 2020 data of 544 patients (315 [58%] men, 55±16 y), consecutive patients submitted for PVC ablation, were prospectively collected. Patients with left ventricle (LV) systolic disfunction (LVEF<50%) were included in a prospective protocol and followed at 6 and 12 months, and annually thereafter. Baseline characteristic as well ablation outcomes were analyzed based on the presence of DM.

RESULTS

Sixty (11%) patients had DM. Patients with DM more frequently had a PVC's site of origin (SOO) in the LV (45 [75%] vs. 229 [48%], P<0.001). The most frequent PVC's SOO in DM patients was the LV outflow tract (OT) (35 [58%] patients: 12 aortic cusps; 12 LV summit; 11 in the myocardium immediately inferior to the valvular plane). Fifty-five (92%) patients with DM had an acute successful ablation, without differences compared with patients without DM (55 [92%] vs. 437 [90%], P=0.9). Twenty-tree (38%) DM-patients had LV dysfunction at the ablation time. In these patients, mean PVC burden decreased from 26±11% at baseline to 4±5% (P<0.001); LVEF increased from 36±8% to 42±11% (P<0.01) and NYHA class improved from 2.2±0.6 to 1.8+0.5 (P<0.01), after a mean follow-up of 37±14 months.

CONCLUSIONS

Patients with DM frequently have PVC with a LV-SOO, being the LVOT the most frequent SOO in this population. Among DM patients with LV dysfunction, ablation persistently and significantly reduce the PVC burden improving functional status. Patients with DM have lower benefit in terms of LV function recovery after ablation compared with non-diabetic patients.

Glycemic Control and the Heart: The Tale of Diabetic Cardiomyopathy Continues

Cardiovascular diseases are the leading cause of death in people with diabetes. Diabetic cardiomyopathy (DC) is an important complication of diabetes and represents a distinct subtype of heart failure that occurs in absence of cardiovascular diseases. Chronic hyperglycemia and hyperinsulinemia along with insulin resistance and inflammatory milieu are the main mechanisms involved in the pathophysiology of DC. Changes in lifestyle favoring healthy dietary patterns and physical activity, combined with more innovative anti-diabetes therapies, are the current treatment strategies to safeguard the cardiovascular system. This review aims at providing an updated comprehensive overview of clinical, pathogenetic, and molecular aspects of DC, with a focus on the effects of anti-hyperglycemic drugs on the prevention of pump dysfunction and consequently on cardiovascular health in type 2 diabetes.

Mechanisms of cardiac dysfunction in diabetic cardiomyopathy: molecular abnormalities and phenotypical variants

Diabetic cardiomyopathy (DCM) is a diabetes mellitus-induced pathophysiological condition characterized by cardiac structural, functional, and metabolic changes that can result in heart failure (HF), in the absence of coronary artery disease, hypertension, and valvular heart disease. Metabolic alterations such as hyperglycemia, insulin resistance, hyperinsulinemia, and increased metabolism of free fatty acids result in oxidative stress, inflammation, advanced glycation end products formation, abnormalities in calcium homeostasis, and apoptosis that are responsible for structural remodeling. Cardiac stiffness, hypertrophy, and fibrosis eventually lead to dysfunction and HF with preserved ejection fraction and/or HF with reduced ejection fraction. In this review, we analyzed in detail the cellular and molecular mechanisms and the metabolic pathways involved in the pathophysiology of DCM. Different phenotypes are observed in DCM, and it is not clear yet if the restrictive and the dilated phenotypes are distinct or represent an evolution of the same disease. Phenotypic differences can be observed between T1DM and T2DM DCM, possibly explained by the different myocardial insulin action. Further studies are needed in order to better understand the underlying mechanisms of DCM and to identify appropriate therapeutic targets and novel strategies to prevent and reverse the progression toward heart failure in diabetic patients.

Diabetic cardiomyopathy: Clinical phenotype and practice

Diabetic cardiomyopathy (DCM) is a pathophysiological condition of cardiac structure and function changes in diabetic patients without coronary artery disease, hypertension, and other types of heart diseases. DCM is not uncommon in people with diabetes, which increases the risk of heart failure. However, the treatment is scarce, and the prognosis is poor. Since 1972, one clinical study after another on DCM has been conducted. However, the complex phenotype of DCM still has not been fully revealed. This dilemma hinders the pace of understanding the essence of DCM and makes it difficult to carry out penetrating clinical or basic research. This review summarizes the literature on DCM over the last 40 years and discusses the overall perspective of DCM, phase of progression, potential clinical indicators, diagnostic and screening criteria, and related randomized controlled trials to understand DCM better.

Role of inflammation in diabetic cardiomyopathy

The prevalence of type 2 diabetes (T2D) has reached a pandemic scale. Systemic chronic inflammation dominates the diabetes pathophysiology and has been implicated as a causal factor for the development of vascular complications. Heart failure (HF) is regarded as the most common cardiovascular complication of T2D and the diabetic diagnosis is an independent risk factor for HF development. Key molecular mechanisms pivotal to the development of diabetic cardiomyopathy include the NF-κB pathway and renin-angiotensin-aldosterone system, in addition to advanced glycation end product accumulation and inflammatory interleukin overexpression. Chronic myocardial inflammation in T2D mediates structural and metabolic changes, including cardiomyocyte apoptosis, impaired calcium handling, myocardial hypertrophy and fibrosis, all of which contribute to the diabetic HF phenotype. Advanced cardiovascular magnetic resonance imaging (CMR) has emerged as a gold standard non-invasive tool to delineate myocardial structural and functional changes. This review explores the role of chronic inflammation in diabetic cardiomyopathy and the ability of CMR to identify inflammation-mediated myocardial sequelae, such as oedema and diffuse fibrosis.

A presystolic wave could easily detect subclinical left ventricular dysfunction in prediabetic patients with no history of hypertension

BACKGROUND

Prediabetes is associated with left ventricular (LV) systolic and diastolic dysfunction. A presystolic wave (PSW) is detected on late diastole from the Doppler examination of the LV outflow tract and is related to LV dysfunction. LV dysfunction could be detected with different echocardiographic methods, including conventional Doppler and Tissue Doppler imaging (TDI), 2D speckle tracking echocardiography, and myocardial performance index (MPI). In this study, we aimed to investigate the association of the presence of PSW with LV dysfunction assessed by different echocardiographic methods.

METHODS

A total of 137 prediabetic normotensive patients were enrolled in this study. Eighty-one (59.1%) patients had a PSW and 36 (40.9%) patients had not PSW on the Doppler examinations. Echocardiographic features were compared between these groups. LV dysfunction was determined based on MPI, LV global longitudinal strain (LVGLS), and conventional Doppler and TDI measurements.

RESULTS

There were no differences between groups regarding clinical and laboratory parameters, except LDL, which was significantly higher in the PSW-positive group. The PSW-positive group had lower E, Em, Ea, E/A, Em/Am, Ea/Aa, LVGLS and higher A, Am, Aa, E/e', isovolumetric relaxation time, and MPI than PSW-negatives. PSW velocity was moderately correlated with MPI (R = .33, p = .003) and LVGLS (R = .35, p = .001). The presence of PSW was independently associated with LV dysfunction assessed by MPI (OR = 3.87, p < .001), LVGLS (OR = 10.29, p < .001), and conventional Doppler and TDI parameters (OR = 8.87, p < .001).

CONCLUSION

PSW was significantly associated with subclinical LV dysfunction in prediabetic normotensive patients assessed with three echocardiographic methods.

Heart failure in diabetes

Heart failure and cardiovascular disorders represent the leading cause of death in diabetic patients. Here we present a systematic review of the main mechanisms underlying the development of diabetic cardiomyopathy. We also provide an excursus on the relative contribution of cardiomyocytes, fibroblasts, endothelial and smooth muscle cells to the pathophysiology of heart failure in diabetes. After having described the preclinical tools currently available to dissect the mechanisms of this complex disease, we conclude with a section on the most recent updates of the literature on clinical management.

Three-Dimensional Global Left Ventricular Myocardial Strain Reduced in All Directions in Subclinical Diabetic Cardiomyopathy: A Systematic Review and Meta-Analysis

Background

Three‐dimensional (3D) speckle tracking echocardiography can identify subclinical diabetic cardiomyopathy without geometric assumption and loss of speckle from out‐of‐plane motions. There is, however, significant heterogeneity among the previous reports. We performed a systematic review and meta‐analysis to compare 3D strain values between adults with asymptomatic, subclinical diabetes mellitus (ie, patients with diabetes mellitus without known clinical manifestations of cardiac disease) and healthy controls.

Methods and Results

After systematic review of 5 databases, 12 valid studies (544 patients with diabetes mellitus and 489 controls) were eligible for meta‐analysis. Pooled means and mean difference (MD) using a random‐effects model for 3D global longitudinal, circumferential, radial, and area strain were calculated. Patients with diabetes mellitus had an overall 2.31 percentage points lower 3D global longitudinal strain than healthy subjects (16.6%, 95% CI, 15.7–17.6 versus 19.0; 95% CI, 18.2–19.7; MD, −2.31, 95% CI, −2.72 to −2.03). Similarly, 3D global circumferential strain (18.9%; 95% CI, 17.5–20.3 versus 20.5; 95% CI, 18.9–22.1; MD, −1.50; 95% CI, −2.09 to −0.91); 3D global radial strain (44.6%; 95% CI, 40.2–49.1 versus 48.2; 95% CI, 44.7–51.8; MD, −3.47; 95% CI, −4.98 to −1.97), and 3D global area strain (30.5%; 95% CI, 29.2–31.8 versus 32.4; 95% CI, 30.5–34.3; MD, −1.76; 95% CI, −2.74 to −0.78) were also lower in patients with diabetes mellitus. Significant heterogeneity was noted between studies for all strain directions (inconsistency factor [I²], 37%–78%). Meta‐regression in subgroup analysis of studies using the most popular vendor found higher prevalence of hypertension as a significant contributor to worse 3D global longitudinal strain. Higher hemoglobulin A_1c was the most significant contributor to worse 3D global circumferential strain in patients with diabetes mellitus.

Conclusions

Three‐dimensional myocardial strain was reduced in all directions in asymptomatic diabetic patients. Hypertension and hemoglobin A_1c were associated with worse 3D global longitudinal strain and 3D global circumferential strain, respectively.

Registration

URL: https://www.crd.york.ac.uk/prospero; unique identifier: CRD42020197825.

Diabetes and Heart Failure: Multi-Omics Approaches

Diabetes and heart failure, as important global issues, cause substantial expenses to countries and medical systems because of the morbidity and mortality rates. Most people with diabetes suffer from type 2 diabetes, which has an amplifying effect on the prevalence and severity of many health problems such as stroke, neuropathy, retinopathy, kidney injuries, and cardiovascular disease. Type 2 diabetes is one of the cornerstones of heart failure, another health epidemic, with 44% prevalence. Therefore, finding and targeting specific molecular and cellular pathways involved in the pathophysiology of each disease, either in diagnosis or treatment, will be beneficial. For diabetic cardiomyopathy, there are several mechanisms through which clinical heart failure is developed; oxidative stress with mediation of reactive oxygen species (ROS), reduced myocardial perfusion due to endothelial dysfunction, autonomic dysfunction, and metabolic changes, such as impaired glucose levels caused by insulin resistance, are the four main mechanisms. In the field of oxidative stress, advanced glycation end products (AGEs), protein kinase C (PKC), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) are the key mediators that new omics-driven methods can target. Besides, diabetes can affect myocardial function by impairing calcium (Ca) homeostasis, the mechanism in which reduced protein phosphatase 1 (PP1), sarcoplasmic/endoplasmic reticulum Ca2+ ATPase 2a (SERCA2a), and phosphorylated SERCA2a expressions are the main effectors. This article reviewed the recent omics-driven discoveries in the diagnosis and treatment of type 2 diabetes and heart failure with focus on the common molecular mechanisms.

Diabetes Mellitus and Heart Failure

Diabetes mellitus (DM) is a major risk factor for new-onset heart failure (HF) and vice versa. The pathogenesis of new-onset HF in DM is complex and has been largely attributed to the toxic cardiovascular effects of hyperglycemia and relevant metabolic abnormalities (diabetic cardiomyopathy) as well as the frequently coexisting morbidities such as hypertension (HTN), coronary artery disease (CAD), and diabetic nephropathy. In patients with type 1 DM (T1DM), HF develops in the setting of a dysregulated immune response, whereas in most patients with type 2 DM (T2DM), against a background of overweight/obesity. HF prevention in DM is feasible with rigorous treatment of cardiovascular risk factors and selective antidiabetic agents. Conversely, development of new-onset T2DM in HF (cardiogenic DM) is common and has been attributed to an increase in the resistance to insulin, especially in the skeletal muscle, liver, and adipose tissue as well as in diminished insulin secretory response to hyperglycemia by pancreatic β-cells. Cardiogenic DM further deteriorates cardiac dysfunction and adversely affects outcome in HF. Novel lifesaving medications employed in HF management such as sacubitril/valsartan and sodium glucose cotransporter 2 inhibitors (SGLT-2i) have a favorable metabolic profile and lower the incidence of cardiogenic diabetes. Whether mitigation of cardiogenic DM should be a treatment target in HF deserves further investigation.

Evidence for human diabetic cardiomyopathy

Growing interest has been accumulated in the definition of worsening effects of diabetes in the cardiovascular system. This is associated with epidemiological data regarding the high incidence of heart failure (HF) in diabetic patients. To investigate the detrimental effects both of hyperglycemia and insulin resistance, a lot of preclinical models were developed. However, the evidence of pathogenic and histological alterations of the so-called diabetic cardiomyopathy (DCM) is still poorly understood in humans. Here, we provide a stringent literature analysis to investigate unique data regarding human DCM. This approach established that lipotoxic-related events might play a central role in the initiation and progression of human DCM. The major limitation in the acquisition of human data is due to the fact of heart specimen availability. Postmortem analysis revealed the end stage of the disease; thus, we need to gain knowledge on the pathogenic events from the early stages until cardiac fibrosis underlying the end-stage HF.

The Genetic Pathways Underlying Immunotherapy in Dilated Cardiomyopathy

Heart failure (HF) is a global public health threat affecting 26 million individuals worldwide with an estimated prevalence increase of 46% by 2030. One of the main causes of HF and sudden death in children and adult is Dilated Cardiomyopathy (DCM). DCM is characterized by dilation and systolic dysfunction of one or both ventricles. It has an underlying genetic basis or can develop subsequent to various etiologies that cause myocardium inflammation (secondary causes). The morbidity and mortality rates of DCM remains high despite recent advancement to manage the disease. New insights have been dedicated to better understand the pathogenesis of DCM in respect to genetic and inflammatory basis by linking the two entities together. This cognizance in the field of cardiology might have an innovative approach to manage DCM through targeted treatment directed to the causative etiology. The following review summarizes the genetical and inflammatory causes underlying DCM and the pathways of the novel precision-medicine-based immunomodulatory strategies to salvage and prevent the associated heart failure linked to the disease.

Concurrent diabetes and heart failure: interplay and novel therapeutic approaches

Diabetes mellitus increases the risk of developing heart failure, and the co-existence of both diseases worsens cardiovascular outcomes, hospitalization and the progression of heart failure. Despite current advancements on therapeutic strategies to manage hyperglycemia, the likelihood of developing diabetes-induced heart failure is still significant, especially with the accelerating global prevalence of diabetes and an ageing population. This raises the likelihood of other contributing mechanisms beyond hyperglycemia in predisposing diabetic patients to cardiovascular disease risk. There has been considerable interest in understanding the alterations in cardiac structure and function in the diabetic patients, collectively termed as "diabetic cardiomyopathy". However, the factors that contribute to the development of diabetic cardiomyopathies is not fully understood. This review summarizes the main characteristics of diabetic cardiomyopathies, and the basic mechanisms that contribute to its occurrence. This includes perturbations in insulin resistance, fuel preference, reactive oxygen species generation, inflammation, cell death pathways, neurohormonal mechanisms, advanced glycated end-products accumulation, lipotoxicity, glucotoxicity, and posttranslational modifications in the heart of the diabetic. This review also discusses the impact of antihyperglycemic therapies on the development of heart failure, as well as how current heart failure therapies influence glycemic control in diabetic patients. We also highlight the current knowledge gaps in understanding how diabetes induces heart failure.

Application of Animal Models in Diabetic Cardiomyopathy

Diabetic heart disease is a growing and important public health risk. Apart from the risk of coronary artery disease or hypertension, diabetes mellitus (DM) is a well-known risk factor for heart failure in the form of diabetic cardiomyopathy (DiaCM). Currently, DiaCM is defined as myocardial dysfunction in patients with DM in the absence of coronary artery disease and hypertension. The underlying pathomechanism of DiaCM is partially understood, but accumulating evidence suggests that metabolic derangements, oxidative stress, increased myocardial fibrosis and hypertrophy, inflammation, enhanced apoptosis, impaired intracellular calcium handling, activation of the renin-angiotensin-aldosterone system, mitochondrial dysfunction, and dysregulation of microRNAs, among other factors, are involved. Numerous animal models have been used to investigate the pathomechanisms of DiaCM. Despite some limitations, animal models for DiaCM have greatly advanced our understanding of pathomechanisms and have helped in the development of successful disease management strategies. In this review, we summarize the current pathomechanisms of DiaCM and provide animal models for DiaCM according to its pathomechanisms, which may contribute to broadening our understanding of the underlying mechanisms and facilitating the identification of possible new therapeutic targets.

Cardiovascular and systemic determinants of exercise capacity in people with type 2 diabetes mellitus

The global burden of heart failure (HF) is on the rise owing to an increasing incidence of lifestyle related diseases, predominantly type 2 diabetes mellitus (T2D). Diabetes is an independent risk factor for cardiovascular disease, and up to 75% of those with T2D develop HF in their lifetime. T2D leads to pathological alterations within the cardiovascular system, which can progress insidiously and asymptomatically in the absence of conventional risk factors. Reduced exercise tolerance is consistently reported, even in otherwise asymptomatic individuals with T2D, and is the first sign of a failing heart. Because aggressive modification of cardiovascular risk factors does not eliminate the risk of HF in T2D, it is likely that other factors play a role in the pathogenesis of HF. Early identification of individuals at risk of HF is advantageous, as it allows for modification of the reversible risk factors and early initiation of treatment with the aim of improving clinical outcomes. In this review, cardiac and extra-cardiac contributors to reduced exercise tolerance in people with T2D are explored.

Diabetic Cardiomiopathy Progression is Triggered by miR122-5p and Involves Extracellular Matrix: A 5-Year Prospective Study

OBJECTIVES

The purpose of this study was to follow the long-term progression of diabetic cardiomyopathy by combining cardiac magnetic resonance (CMR) and molecular analysis.

BACKGROUND

The evolution of diabetic cardiomyopathy to heart failure affects patients'morbidity and mortality. CMR is the gold standard to assess cardiac remodeling, but there is a lack of markers linked to the mechanism of diabetic cardiomyopathy progression.

METHODS

Five-year longitudinal study on patients with type 2 diabetes mellitus (T2DM) enrolled in the CECSID (Cardiovascular Effects of Chronic Sildenafil in Men With Type 2 Diabetes) trial compared with nondiabetic age-matched controls. CMR with tagging together with metabolic and molecular assessments were performed at baseline and 5-year follow-up.

RESULTS

A total of 79 men (age 64 ± 8 years) enrolled, comprising 59 men with T2DM compared with 20 nondiabetic age-matched controls. Longitudinal CMR with tagging showed an increase in ventricular mass (ΔLVMi = 13.47 ± 29.66 g/m²; p = 0.014) and a borderline increase in end-diastolic volume (ΔEDVi = 5.16 ± 14.71 ml/m²; p = 0.056) in men with T2DM. Cardiac strain worsened (Δσ = 1.52 ± 3.85%; p = 0.033) whereas torsion was unchanged (Δθ = 0.24 ± 4.04°; p = 0.737), revealing a loss of the adaptive equilibrium between strain and torsion. Contraction dynamics showed a decrease in the systolic time-to-peak (ΔTtP = -35.18 ± 28.81 ms; p < 0.001) and diastolic early recoil-rate (ΔRR = -20.01 ± 19.07 s^-1; p < 0.001). The ejection fraction and metabolic parameters were unchanged. Circulating miR microarray revealed an up-regulation of miR122-5p. Network analysis predicted the matrix metalloproteinases (MMPs) MMP-16 and MMP-2 and their regulator (tissue inhibitors of metalloproteinases) as targets. In db/db mice we demonstrated that miR122-5p expression is associated with diabetic cardiomyopathy, that in the diabetic heart is overexpressed, and that, in vitro, it regulates MMP-2. Finally, we demonstrated that miR122-5p overexpression affects the extracellular matrix through MMP-2 modulation.

CONCLUSIONS

Within 5 years of diabetic cardiomyopathy onset, increasing cardiac hypertrophy is associated with progressive impairment in strain, depletion of the compensatory role of torsion, and changes in viscoelastic contraction dynamics. These changes are independent of glycemic control and paralleled by the up-regulation of specific microRNAs targeting the extracellular matrix. (Cardiovascular Effects of Chronic Sildenafil in Men With Type 2 Diabetes [CECSID]; NCT00692237).

Diabetic Cardiomyopathy: Clinical and Metabolic Approach

BACKGROUND

Having in mind that diabetes mellitus (DM) and obesity are some of the greatest health challenges of the modern era, diabetic cardiomyopathy (DCM) is becoming more and more recognized in clinical practice. Main Text: Initially, DM is asymptomatic, but it may progress to diastolic and then systolic left ventricular dysfunction, which results in congestive heart failure. A basic feature of this DM complication is the absence of hemodynamically significant stenosis of the coronary blood vessels. Clinical manifestations are the result of several metabolic disorders that are present during DM progression. The complexity of metabolic processes, along with numerous regulatory mechanisms, has been the subject of research that aims at discovering new diagnostic (e.g. myocardial strain with echocardiography and cardiac magnetic resonance) and treatment options. Adequate glycaemic control is not sufficient to prevent or reduce the progression of DCM. Contemporary hypoglycemic medications, such as sodium-glucose transport protein 2 inhibitors, significantly reduce the frequency of cardiovascular complications in patients with DM. Several studies have shown that, unlike the above-stated medications, thiazolidinediones and dipeptidyl peptidase-4 inhibitors are associated with deterioration of heart failure.

CONCLUSION

Imaging procedures, especially myocardial strain with echocardiography and cardiac magnetic resonance, are useful to identify the early signs of DCM. Research and studies regarding new treatment options are still "in progress".

Diabetic Cardiomyopathy as a Clinical Entity: Is It a Myth?

Dilated cardiomyopathy (DCM) is a common form of cardiomyopathy that affects the cardiac muscle. It is a life-threatening condition that causes heart failure as it decreases the myocardial ability to pump sufficient blood throughout the body. Numerous causes trigger DCM without pathophysiology; however, the key concept is a decrease in the systolic function of either the left ventricle or of both the left and right ventricles. Long-term diabetes plays an important role in the pathogenesis of DCM in the form of diabetic cardiomyopathy. Diabetic cardiomyopathy is a non-ischemic form of DCM, which is associated with diabetes. It is unrelated to atherosclerosis and hypertension. The PubMed and Google Scholar databases were used to identify the relevant studies related to diabetes and DCM. We found that diabetes was associated with cardiac muscle injury by activating the renin-angiotensin-aldosterone system, myocardial inflammation, and fibrosis. Based on the available data, we concluded that there is strong evidence to support the interrelation of DCM and diabetes.

Morphological characteristics in diabetic cardiomyopathy associated with autophagy

Diabetic cardiomyopathy, clinically diagnosed as ventricular dysfunction in the absence of coronary atherosclerosis or hypertension in diabetic patients, is a cardiac muscle-specific disease that increases the risk of heart failure and mortality. Its clinical course is characterized initially by diastolic dysfunction, later by systolic dysfunction, and eventually by clinical heart failure from an uncertain mechanism. Light microscopic features such as interstitial fibrosis, inflammation, and cardiomyocyte hypertrophy are observed in diabetic cardiomyopathy, but are common to failing hearts generally and are not specific to diabetic cardiomyopathy. Electron microscopic studies of biopsy samples from diabetic patients with heart failure have revealed that the essential mechanism underlying diabetic cardiomyopathy involves thickening of the capillary basement membrane, accumulation of lipid droplets, and glycogen as well as increased numbers of autophagic vacuoles within cardiomyocytes. Autophagy is a conserved mechanism that contributes to maintaining intracellular homeostasis by degrading long-lived proteins and damaged organelles and is observed more often in cardiomyocytes within failing hearts. Diabetes mellitus (DM) impairs cardiac metabolism and leads to dysregulation of energy substrates that contribute to cardiac autophagy. However, a "snapshot" showing greater numbers of autophagic vacuoles within cardiomyocytes may indicate that autophagy is activated into phagophore formation or is suppressed due to impairment of the lysosomal degradation step. Recent in vivo studies have shed light on the underlying molecular mechanism governing autophagy and its essential meaning in the diabetic heart. Autophagic responses to diabetic cardiomyopathy differ between diabetic types: they are enhanced in type 1 DM, but are suppressed in type 2 DM. This difference provides important insight into the pathophysiology of diabetic cardiomyopathy. Here, we review recent advances in our understanding of the pathophysiology of diabetic cardiomyopathy, paying particular attention to autophagy in the heart, and discuss the therapeutic potential of interventions modulating autophagy in diabetic cardiomyopathy.

The Peroxisome Proliferator-Activated Receptor-Gamma Coactivator-1α-Heme Oxygenase 1 Axis, a Powerful Antioxidative Pathway with Potential to Attenuate Diabetic Cardiomyopathy

Significance: From studies of diabetic animal models, the downregulation of peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α)-heme oxygenase 1 (HO-1) axis appears to be a crucial event in the development of obesity and diabetic cardiomyopathy (DCM). In this review, we discuss the role of metabolic and biochemical stressors in the rodent and human pathophysiology of DCM. A crucial contributor for many cardiac pathologies is excessive production of reactive oxygen species (ROS) pathologies, which lead to extensive cellular damage by impairing mitochondrial function and directly oxidizing DNA, proteins, and lipid membranes. We discuss the role of ROS production and inflammatory pathways with multiple contributing and confounding factors leading to DCM. Recent Advances: The relevant biochemical pathways that are critical to a therapeutic approach to treat DCM, specifically caloric restriction and its relation to the PGC-1α-HO-1 axis in the attenuation of DCM, are elucidated. Critical Issues: The increased prevalence of diabetes mellitus type 2, a major contributor to unique cardiomyopathy characterized by cardiomyocyte hypertrophy with no effective clinical treatment. This review highlights the role of mitochondrial dysfunction in the development of DCM and potential oxidative targets to attenuate oxidative stress and attenuate DCM. Future Directions: Targeting the PGC-1α-HO-1 axis is a promising approach to ameliorate DCM through improvement in mitochondrial function and antioxidant defenses. A pharmacological inducer to activate PGC-1α and HO-1 described in this review may be a promising therapeutic approach in the clinical setting.

Role of sodium-glucose co-transporter-2 inhibitors in the management of heart failure in patients with diabetes mellitus

Heart failure (HF) is a major complication of diabetes mellitus (DM). Patients with DM have considerably higher risk for HF than non-diabetic subjects and HF is also more severe in the former. Given the rising prevalence of DM, the management of HF in diabetic patients has become the focus of increased attention. In this context, the findings of several randomized, placebo-controlled trials that evaluated the effects of sodium-glucose co-transporter-2 inhibitors on the risk of hospitalization for HF in patients with type 2 DM represent a paradigm shift in the management of HF. These agents consistently reduced the risk of hospitalization for HF both in patients with and in those without HF. These benefits appear to be partly independent from glucose-lowering and have also been reported in patients without DM. However, there are more limited data regarding the benefit of sodium-glucose co-transporter-2 inhibitors in patients with HF and preserved left ventricular ejection fraction, which is the commonest type of HF in diabetic patients.

Therapeutic approaches to diabetic cardiomyopathy: Targeting the antioxidant pathway

The global epidemic of cardiovascular disease continues unabated and remains the leading cause of death both in the US and worldwide. We hereby summarize the available therapies for diabetes and cardiovascular disease in diabetics. Clearly, the current approaches to diabetic heart disease often target the manifestations and certain mediators but not the specific pathways leading to myocardial injury, remodeling and dysfunction. Better understanding of the molecular events determining the evolution of diabetic cardiomyopathy will provide insight into the development of specific and targeted therapies. Recent studies largely increased our understanding of the role of enhanced inflammatory response, ROS production, as well as the contribution of Cyp-P450-epoxygenase-derived epoxyeicosatrienoic acid (EET), Peroxisome Proliferator-Activated Receptor Gamma Coactivator-1α (PGC-1α), Heme Oxygenase (HO)-1 and 20-HETE in pathophysiology and therapy of cardiovascular disease. PGC-1α increases production of the HO-1 which has a major role in protecting the heart against oxidative stress, microcirculation and mitochondrial dysfunction. This review describes the potential drugs and their downstream targets, PGC-1α and HO-1, as major loci for developing therapeutic approaches beside diet and lifestyle modification for the treatment and prevention of heart disease associated with obesity and diabetes.

Can Wogonin be Used in Controlling Diabetic Cardiomyopathy?

Diabetes Mellitus (DM) is now a well-known factor which initiates many metabolic derangements in various tissues and organs including liver, muscle, pancreas, adipose tissue, cardiovascular and nervous system. Cardiovascular complications are the most crucial , and their effects are so intensive that their derangement leads to cardiac failure even in the absence of ischemic heart diseases. This entity of cardiac pathology in DM is often regarded as diabetic cardiomyopathy (DCM). Recently, many plant-derived drugs have been tested to control and alleviate DCM. Wogonin is one of the drugs the characteristics of which have been deeply studied. Wogonin is a flavonoid having yellow color pigment in their leaves and is obtained from the roots of plant Scutellaria Baicalensis Georgi. Wogonin has long been used as an active anti-cancer drug in Chinese medicine practice. In recent past wogonin has shown to possess notable anti-inflammatory, and anti-allergic properties. Wogonin has demonstrated to possess anti-oxidant, anti-viral, anti-inflammatory and also anti-thrombotic properties. Wogonin has shown to alleviate apoptosis, and ER stress in the cells and this property can also be used in the treatment of cardiovascular diseases. Notably, wogonin has been documented to have an extensive margin of safety as well as displays little or no organ toxicity following extended intravenous administration. In this review, we discuss recently discovered therapeutic potential of wogonin in the treatment of DCM.

Diabetic cardiomyopathy

The relationship between diabetes and heart failure is complex and bidirectional. Nevertheless, the existence of a cardiomyopathy attributable exclusively to diabetes has been and is still the subject of controversy, due, among other reasons, to a lack of a consensus definition. There is also no unanimous agreement in terms of the physiopathogenic findings that need to be present in the definition of diabetic cardiomyopathy or on its classification, which, added to the lack of diagnostic methods and treatments specific for this disease, limits its general understanding. Studies conducted on diabetic cardiomyopathy, however, suggest a unique physiopathogenesis different from that of other diseases. Similarly, new treatments have been shown to play a potential role in this disease. The following review provides an update on diabetic cardiomyopathy.

Left ventricular functions in pediatric patients with ten years or more type 1 diabetes mellitus: Conventional echocardiography, tissue Doppler, and two-dimensional speckle tracking study

BACKGROUND

Cardiac dysfunction is a complication of type 1 diabetes mellitus (T1DM) with primary concern in adults. However, studies have evaluated left ventricle (LV) myocardial changes in pediatrics but not the long-term effect of T1DM in such vulnerable age. Therefore, we assessed LV functions in pediatric patients with long-duration T1DM using different echocardiographic modalities.

METHODS

Between July 2015 and March 2016, 48 T1DM patients were prospectively compared to 35 healthy controls. Pediatric patients with T1DM for 10 years or more were included in the study. Patients were subjected to history taking, clinical examination, glycated hemoglobin (HbA1c), and microalbuminuria measurements. Moreover, conventional echocardiography, tissue Doppler, and 2D speckle tracking were performed to analyze LV functions.

RESULTS

Mean age of patients was 15.5 ± 2 years, and mean T1DM duration was 11.7 ± 1.8 years. LV dimensions, EF and FS, and mass index did not statistically differ between groups, but E/E' ratio was significantly higher in the diabetic group. Global longitudinal strain (GLS) and global circumferential strain (GCS) were significantly lower in diabetic patients compared with controls (P = 0.038; P = 0.001, respectively). Mean HbA1c was found to be a significant predictor of decreased GLS in the diabetic population (95% CI, 0.096-0.244; P = 0.001) but not predicting GCS. Microalbuminuria had no significance in predicting strain.

CONCLUSIONS

Despite the long-duration of affection with T1DM during childhood in our patients, alterations on LV myocardial function could not be detected either clinically or by conventional echocardiography. Tissue Doppler and speckle tracking could be used in the follow up of myocardial status in pediatric diabetic patients.

Left Ventricular Diastolic Dysfunction in Type 2 Diabetes-Progress and Perspectives

In-depth understanding of early cardiovascular manifestations in diabetes is high on international research and prevention agendas given that cardiovascular events are the leading cause of death for diabetic patients. Our aim was to review recent developments in the echocardiographic assessment of left ventricular diastolic dysfunction (LVDD) as a telltale pre-clinical disturbance preceding diabetic cardiomyopathy. We analyzed papers in which patients had been comprehensively assessed echocardiographically according to the latest LVDD guidelines (2016), and those affording comparisons with previous, widely used recommendations (2009). We found that the updated algorithm for LVDD is more effective in predicting adverse cardiovascular events in patients with established LVDD, and less specific in grading other patients (labelled "indeterminate"). This may prove instrumental for recruiting "indeterminate" LVDD cases among patients with type 2 diabetes mellitus (T2DM) in future screening programs. As an interesting consideration, the elevated values of the index E/e' can point to early diastolic impairment, foretelling diabetic cardiomyopathy. Identifying subclinical signs early makes clinical sense, but the complex nature of T2DM calls for further research. Specifically, longitudinal studies on rigorously selected cohorts of diabetic patients are needed to better understand and predict the subtle, slow onset of cardiac manifestations with T2DM as a complicating backdrop.

Enhanced mTOR complex 1 signaling attenuates diabetic cardiac injury in OVE26 mice

The protein kinase mechanistic target of rapamycin (mTOR) performs diverse cellular functions through 2 distinct multiprotein complexes, mTOR complex (mTORC)1 and 2. Numerous studies using rapamycin, an mTORC1 inhibitor, have implicated a role for mTORC1 in several types of heart disease. People with diabetes are more susceptible to heart failure. mTORC1 activity is increased in the diabetic heart, but its functional significance remains controversial. To investigate the role of mTORC1 in the diabetic heart, we crossed OVE26 type 1 diabetic mice with transgenic mice expressing a constitutively active mTOR (mTORca) or kinase-dead mTOR (mTORkd) in the heart. The expression of mTORca or mTORkd affected only mTORC1 but not mTORC2 activities, with corresponding changes in the activities of autophagy, a cellular degradation pathway negatively regulated by mTORC1. Diabetic cardiac damage in OVE26 mice was dramatically reduced by mTORca but exacerbated by mTORkd expression as assessed by changes in cardiac function, oxidative stress, and myocyte apoptosis. These findings demonstrated that the enhanced mTORC1 signaling in the OVE26 diabetic heart was an adaptive response that limited cardiac dysfunction, suggesting that manipulations that enhance mTORC1 activity may reduce diabetic cardiac injury, in sharp contrast to the results previously obtained with rapamycin.-Xu, X., Kobayashi, S., Timm, D., Huang, Y., Zhao, F., Shou, W., Liang, Q. Enhanced mTOR complex 1 signaling attenuates diabetic cardiac injury in OVE26 mice.

Mesenchymal stem cells promote type 2 macrophage polarization to ameliorate the myocardial injury caused by diabetic cardiomyopathy

BACKGROUND

Diabetic cardiomyopathy (DCM) is a common complication of diabetes and is characterized by chronic myocardial inflammation. Mesenchymal stem cell (MSC) infusions have recently been suggested to alleviate myocardial injury and ameliorate cardiac function. However, few studies have focused on the effects of MSCs in DCM. Therefore, we explored the effects of MSC-regulated macrophage polarization on myocardial repair in DCM.

METHODS

A DCM rat model was induced by a high-fat diet and streptozotocin (STZ) administration and infused 4 times with MSCs. Rat blood and heart tissue were analyzed for blood glucose levels, lipid levels, echocardiography, histopathology, macrophage phenotype ratios and inflammatory cytokines, respectively. We mimicked chronic inflammation in vitro by inducing peritoneal macrophages with high glucose and LPS, then cocultured these macrophages with MSCs to explore the specific mechanism of MSCs on macrophage polarization.

RESULTS

DCM rats exhibited abnormal blood glucose levels and lipid metabolism, cardiac inflammation and dysfunction. MSC infusion ameliorated metabolic abnormalities and preserved cardiac structure and function in DCM rats. Moreover, MSC infusion significantly increased the M2 phenotype macrophages and alleviated cardiac inflammation. Interestingly, this in vitro study revealed that the MSCs pretreated with a COX-2 inhibitor had little effect on M2 macrophage polarization, but this phenomenon could be reversed by adding prostaglandin E2 (PGE2).

CONCLUSIONS

Our results suggested that MSC infusions can protect against cardiac injury in DCM rats. The underlying mechanisms may include MSC-enhanced M2 macrophage polarization via the COX-2-PGE2 pathway.

Treatment options in myocarditis and inflammatory cardiomyopathy : Focus on i. v. immunoglobulins

For myocarditis and inflammatory cardiomyopathy, an etiologically driven treatment is today the best option beyond heart failure therapy. Prerequisites for this are noninvasive and invasive biomarkers including endomyocardial biopsy and polymerase chain reaction on cardiotropic agents. Imaging by Doppler echocardiography and cardiac magnetic resonance imaging as well as cardiac biomarkers such as C‑reactive protein, N‑terminal pro-B-type natriuretic peptide , and troponins can contribute to the clinical work-up of the syndrome but not toward elucidating the underlying cause or pathogenetic process. This review summarizes the phases and clinical features of myocarditis and gives an up-to-date short overview of the current treatment options starting with heart failure and antiarrhythmic therapy. Although inflammation in myocardial disease can resolve spontaneously, often specific treatment directed against the causative agent is required. For fulminant, acute, and chronic autoreactive myocarditis, immunosuppressive treatment has proven to be beneficial in the TIMIC and ESETCID trials; for viral cardiomyopathy and myocarditis, intravenous immunoglobulin IgG subtype and polyvalent intravenous immunoglobulins IgG, IgA, and IgM can frequently resolve inflammation. However, despite the elimination of inflammation, the eradication of parvovirus B19 and human herpesvirus-6 is still a challenge, for which ivIg treatment can become a future key player.

Molecular Dysfunction and Phenotypic Derangement in Diabetic Cardiomyopathy

The high incidence and poor prognosis of heart failure (HF) patients affected with diabetes (DM) is in part related to a specific cardiac remodeling currently recognized as diabetic cardiomyopathy (DCM). This cardiac frame occurs regardless of the presence of coronary artery diseases (CAD) and it can account for 15–20% of the total diabetic population. The pathogenesis of DCM remains controversial, and several molecular and cellular alterations including myocardial hypertrophy, interstitial fibrosis, oxidative stress and vascular inflammation, have been postulated. The main cardio-vascular alterations associated with hyperglycemia comprise endothelial dysfunction, adverse effects of circulating free fatty acids (FFA) and increased systemic inflammation. High glucose concentrations lead to a loss of mitochondrial networks, increased reactive oxygen species (ROS), endothelial nitric oxide synthase (eNOS) activation and a reduction in cGMP production related to protein kinase G (PKG) activity. Current mechanisms enhance the collagen deposition with subsequent increased myocardial stiffness. Several concerns regarding the exact role of DCM in HF development such as having an appearance as either dilated or as a concentric phenotype and whether diabetes could be considered a causal factor or a comorbidity in HF, remain to be clarified. In this review, we sought to explain the different DCM subtypes and the underlying pathophysiological mechanisms. Therefore, the traditional and new molecular and signal alterations and their relationship with macroscopic structural abnormalities are described.