The impact of diabetes on left ventricular filling pattern in normotensive and hypertensive adults: the Strong Heart Study

Targeting Rab7-Rilp Mediated Microlipophagy Alleviates Lipid Toxicity in Diabetic Cardiomyopathy

Diabetic cardiomyopathy (DbCM) is characterized by diastolic dysfunction, which progresses into heart failure and aberrant electrophysiology in diabetic patients. Dyslipidemia in type 2 diabetic patients leads to the accumulation of lipid droplets (LDs) in cardiomyocytes and results in lipid toxicity which has been suggested to drive DbCM. It is aimed to explore potential pathways that may boost LDs degradation in DbCM and restore cardiac function. LDs accumulation resulted in an increase in lipid toxicity in DbCM hearts is confirmed. Microlipophagy pathway, rather than traditional macrolipophagy, is activated in DbCM hearts. RNA-Seq data and Rab7-CKO mice implicate that Rab7 is a major modulator of the microlipophagy pathway. Mechanistically, Rab7 is phosphorylated at Tyrosine 183, which allows the recruitment of Rab-interacting lysosome protein (Rilp) to proceed LDs degradation by lysosome. Treating DbCM mice with Rab7 activator ML-098 enhanced Rilp level and rescued the observed cardiac dysfunction. Overall, Rab7-Rilp-mediated microlipophagy may be a promising target in the treatment of lipid toxicity in DbCM is suggested.

Prognostic value of E/e' ratio and its change over time in ST-segment elevation myocardial infarction with preserved left ventricular ejection fraction in the reperfusion era

BACKGROUND

The ratio of early diastolic mitral inflow velocity to mitral annular velocity (E/e') is a prognostic factor in patients with ST-segment elevation myocardial infarction (STEMI). However, data are lacking on long-term outcomes and longitudinal changes in E/e' in patients with preserved left ventricular ejection fraction (LVEF) in the reperfusion era.

METHODS

This is a pre-specified echocardiographic substudy of a randomized controlled trial evaluating the efficacy of beta-blockers in STEMI patients with LVEF ≥40 % after primary percutaneous coronary intervention (PCI). Patients were divided into 2 groups according to E/e' at discharge: ≤14 (normal E/e' group) or > 14 (high E/e' group). The primary outcome was a composite of all-cause death, myocardial infarction, stroke, acute coronary syndrome, and heart failure hospitalization. We also assessed longitudinal changes in E/e' and conducted a landmark analysis using E/e' at 1 year after STEMI.

RESULTS

There were 173 and 38 patients in the normal and high E/e' groups, respectively. During a median follow-up of 3.9 years, the primary outcome occurred in 19 patients (11.0 %) and 10 patients (26.3 %) in the normal and high E/e' groups, respectively. The cumulative incidence of the primary outcome was higher in the high E/e' group than in the normal E/e' group (21.9 % vs. 7.1 % at 3 years; log-rank p = 0.013). E/e' in the high E/e' group decreased over time (p < 0.001), but remained higher than in the normal E/e' group at 1 year after STEMI (13.7 ± 5.3 vs. 8.6 ± 2.3, p < 0.001). E/e' > 14 at 1 year was also associated with poor outcomes (log-rank p = 0.008). A sensitivity analysis using multivariate Cox proportional hazards regression models yielded consistent results.

CONCLUSION

High E/e' at discharge is associated with poor long-term outcomes in STEMI patients with preserved LVEF after primary PCI, which may be explained by persistent high E/e' late after STEMI.

Nrf2 prevents diabetic cardiomyopathy via antioxidant effect and normalization of glucose and lipid metabolism in the heart

Metabolic disorders and oxidative stress are the main causes of diabetic cardiomyopathy. Activation of nuclear factor erythroid 2-related factor 2 (Nrf2) exerts a powerful antioxidant effect and prevents the progression of diabetic cardiomyopathy. However, the mechanism of its cardiac protection and direct action on cardiomyocytes are not well understood. Here, we investigated in a cardiomyocyte-restricted Nrf2 transgenic mice (Nrf2-TG) the direct effect of Nrf2 on cardiomyocytes in DCM and its mechanism. In this study, cardiomyocyte-restricted Nrf2 transgenic mice (Nrf2-TG) were used to directly observe whether cardiomyocyte-specific overexpression of Nrf2 can prevent diabetic cardiomyopathy and correct glucose and lipid metabolism disorders in the heart. Compared to wild-type mice, Nrf2-TG mice showed resistance to diabetic cardiomyopathy in a streptozotocin-induced type 1 diabetes mouse model. This was primarily manifested as improved echocardiography results as well as reduced myocardial fibrosis, cardiac inflammation, and oxidative stress. These results showed that Nrf2 can directly act on cardiomyocytes to exert a cardioprotective role. Mechanistically, the cardioprotective effects of Nrf2 depend on its antioxidation activity, partially through improving glucose and lipid metabolism by directly targeting lipid metabolic pathway of AMPK/Sirt1/PGC-1α activation via upstream genes of sestrin2 and LKB1, and indirectly enabling AKT/GSK-3β/HK-Ⅱ activity via AMPK mediated p70S6K inhibition.

Prevalence and Predictors of Subclinical Cardiomyopathy in Patients With Type 2 Diabetes in a Health System

INTRODUCTION

Diabetic cardiomyopathy (DbCM) is characterized by subclinical abnormalities in cardiac structure/function and is associated with a higher risk of overt heart failure (HF). However, there are limited data on optimal strategies to identify individuals with DbCM in contemporary health systems. The aim of this study was to evaluate the prevalence of DbCM in a health system using existing data from the electronic health record (EHR).

METHODS

Adult patients with type 2 diabetes mellitus free of cardiovascular disease (CVD) with available data on HF risk in a single-center EHR were included. The presence of DbCM was defined using different definitions: (1) least restrictive: ≥1 echocardiographic abnormality (left atrial enlargement, left ventricle hypertrophy, diastolic dysfunction); (2) intermediate restrictive: ≥2 echocardiographic abnormalities; (3) most restrictive: 3 echocardiographic abnormalities. DbCM prevalence was compared across age, sex, race, and ethnicity-based subgroups, with differences assessed using the chi-squared test. Adjusted logistic regression models were constructed to evaluate significant predictors of DbCM.

RESULTS

Among 1921 individuals with type 2 diabetes mellitus, the prevalence of DbCM in the overall cohort was 8.7% and 64.4% in the most and least restrictive definitions, respectively. Across all definitions, older age and Hispanic ethnicity were associated with a higher proportion of DbCM. Females had a higher prevalence than males only in the most restrictive definition. In multivariable-adjusted logistic regression, higher systolic blood pressure, higher creatinine, and longer QRS duration were associated with a higher risk of DbCM across all definitions.

CONCLUSIONS

In this single-center, EHR cohort, the prevalence of DbCM varies from 9% to 64%, with a higher prevalence with older age and Hispanic ethnicity.

Haemodynamic effects of hypertension and type 2 diabetes: Insights from a 4D flow MRI-based personalized cardiovascular mathematical model

Type 2 diabetes (T2D) and hypertension increase the risk of cardiovascular diseases mediated by whole-body changes to metabolism, cardiovascular structure and haemodynamics. The haemodynamic changes related to hypertension and T2D are complex and subject-specific, however, and not fully understood. We aimed to investigate the haemodynamic mechanisms in T2D and hypertension by comparing the haemodynamics between healthy controls and subjects with T2D, hypertension, or both. For all subjects, we combined 4D flow magnetic resonance imaging data, brachial blood pressure and a cardiovascular mathematical model to create a comprehensive subject-specific analysis of central haemodynamics. When comparing the subject-specific haemodynamic parameters between the four groups, the predominant haemodynamic difference is impaired left ventricular relaxation in subjects with both T2D and hypertension compared to subjects with only T2D, only hypertension and controls. The impaired relaxation indicates that, in this cohort, the long-term changes in haemodynamic load of co-existing T2D and hypertension cause diastolic dysfunction demonstrable at rest, whereas either disease on its own does not. However, through subject-specific predictions of impaired relaxation, we show that altered relaxation alone is not enough to explain the subject-specific and group-related differences; instead, a combination of parameters is affected in T2D and hypertension. These results confirm previous studies that reported more adverse effects from the combination of T2D and hypertension compared to either disease on its own. Furthermore, this shows the potential of personalized cardiovascular models in providing haemodynamic mechanistic insights and subject-specific predictions that could aid in the understanding and treatment planning of patients with T2D and hypertension. KEY POINTS: The combination of 4D flow magnetic resonance imaging data and a cardiovascular mathematical model allows for a comprehensive analysis of subject-specific haemodynamic parameters that otherwise cannot be derived non-invasively. Using this combination, we show that diastolic dysfunction in subjects with both type 2 diabetes (T2D) and hypertension is the main group-level difference between controls, subjects with T2D, subjects with hypertension, and subjects with both T2D and hypertension. These results suggest that, in this relatively healthy population, the additional load of both hypertension and T2D affects the haemodynamic function of the left ventricle, whereas each disease on its own is not enough to cause significant effects under resting conditions. Finally, using the subject-specific model, we show that the haemodynamic effects of diastolic dysfunction alone are not sufficient to explain all the observed haemodynamic differences. Instead, additional subject-specific variations in cardiac and vascular function combine to explain the complex haemodynamics of subjects affected by hypertension and/or T2D.

Characterization of left ventricular diastolic parameters of gated-single-photon emission computed tomography myocardial perfusion imaging in patients with diabetes and normal myocardial perfusion and systolic function

BACKGROUND

Diabetic cardiomyopathy is defined as an independent entity with a specified pathological progression from diastolic dysfunction with preserved ejection fraction to overt heart failure. Myocardial perfusion imaging (MPI) with gated-single-photon emission computed tomography (G-SPECT) has been introduced as a feasible tool to evaluate left ventricular (LV) diastolic function. The aim of this study was to investigate the characteristics of diastolic parameters derived from G-SPECT MPI in diabetic patients compared to patients at very low risk of coronary artery disease (CAD) and with no other CAD risk factors.

METHODS

This cross-sectional study was performed on patients referred to the nuclear medicine department for G-SPECT MPI. Demographic and clinical data, as well as medical history, were extracted from a digital registry system including 4447 patients. Then, two matched groups of patients with only diabetes as cardiac risk factor ( n  = 126) and those without any identifiable CAD risk factors ( n  = 126) were selected. Diastolic parameters of MPI, including peak filling rate, time to peak filling rate, mean filling rate at the first third of diastole and second peak filling rate, were derived using quantitative software for eligible cases.

RESULTS

The mean age of the diabetic and nondiabetic groups was 57.1 ± 14.9 and 56.7 ± 10.6 years, respectively ( P  = 0.823). Comparison of quantitative SPECT MPI parameters between the two groups showed a statistically significant difference only in total perfusion deficit scores, whereas none of the functional parameters, including diastolic and dyssynchrony indices and the shape index, were significantly different. There were also no significant differences in diastolic function parameters between diabetes and nondiabetes patients in the age and gender subgroups.

CONCLUSION

Based on the G-SPECT MPI findings, there is a comparable prevalence of diastolic dysfunction in patients with only diabetes as a cardiovascular risk factor and low-risk patients with no cardiovascular risk factors in the setting of normal myocardial perfusion and systolic function.

Insulin-like growth factor II receptor alpha overexpression in heart aggravates hyperglycemia-induced cardiac inflammation and myocardial necrosis

Diabetes-induced cardiovascular complications are mainly associated with high morbidity and mortality in patients with diabetes. Insulin-like growth factor II receptor α (IGF-IIRα) is a cardiac risk factor. In this study, we hypothesized IGF-IIRα could also deteriorate diabetic heart injury. The results presented that both in vivo transgenic Sprague-Dawley rat model with specific IGF-IIRα overexpression in the heart and in vitro myocardium H9c2 cells were used to investigate the negative function of IGF-IIRα in diabetic hearts. The results showed that IGF-IIRα overexpression aided hyperglycemia in creating more myocardial injury. Pro-inflammatory factors, such as Tumor necrosis factor-alpha, Interleukin-6, Cyclooxygenase-2, Inducible nitric oxide synthase, and Nuclear factor-kappaB inflammatory cascade, are enhanced in the diabetic myocardium with cardiac-specific IGF-IIRα overexpression. Correspondingly, IGF-IIRα overexpression in the diabetic myocardium also reduced the PI3K-AKT survival axis and activated mitochondrial-dependent apoptosis. Finally, both ejection fraction and fractional shortening were be significantly decrease in diabetic rats with cardiac-specific IGF-IIRα overexpression. Overall, all results provid clear evidence that IGF-IIRα can enhance cardiac damage and is a harmful factor to the heart under high-blood glucose conditions. However, the pathophysiology of IGF-IIRα under different stresses and its downstream regulation in the heart still require further research.

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.

The interplay of inflammation, exosomes and Ca2+ dynamics in diabetic cardiomyopathy

Diabetes mellitus is one of the prime risk factors for cardiovascular complications and is linked with high morbidity and mortality. Diabetic cardiomyopathy (DCM) often manifests as reduced cardiac contractility, myocardial fibrosis, diastolic dysfunction, and chronic heart failure. Inflammation, changes in calcium (Ca²⁺) handling and cardiomyocyte loss are often implicated in the development and progression of DCM. Although the existence of DCM was established nearly four decades ago, the exact mechanisms underlying this disease pathophysiology is constantly evolving. Furthermore, the complex pathophysiology of DCM is linked with exosomes, which has recently shown to facilitate intercellular (cell-to-cell) communication through biomolecules such as micro RNA (miRNA), proteins, enzymes, cell surface receptors, growth factors, cytokines, and lipids. Inflammatory response and Ca²⁺ signaling are interrelated and DCM  has been known to adversely affect many of these signaling molecules either qualitatively and/or quantitatively. In this literature review, we have demonstrated that Ca²⁺ regulators are tightly controlled at different molecular and cellular levels during various biological processes in the heart. Inflammatory mediators, miRNA and exosomes are shown to interact with these regulators, however how these mediators are linked to Ca²⁺ handling during DCM pathogenesis remains elusive. Thus, further investigations are needed to understand the mechanisms to restore cardiac Ca²⁺ homeostasis and function, and to serve as potential therapeutic targets in the treatment of DCM.

Change in left ventricular diastolic function after pioglitazone treatment in patients with type 2 diabetes mellitus: A protocol for systematic review and meta-analysis

BACKGROUND

Pioglitazone is currently used as an anti-diabetic agent and can reduce cardiovascular events in in patients with type 2 diabetes mellitus (T2DM). Left ventricular diastolic dysfunction has been recognized as an early manifestation of myocardial dysfunction in T2DM patients. This systematic review and meta-analysis aimed to investigate changes in the left ventricular diastolic function after the treatment of pioglitazone.

METHODS

A systematic literature search of PubMed, Embase, and the Cochrane Library until May 2021 with keywords pioglitazone and left ventricular diastolic function was performed in accordance with the meta-analysis of observational studies in epidemiology guidelines and preferred reporting items for systematic reviews and meta-analyses statement. Three reviewers independently selected the studies and extracted data. Quality assessment of the included studies was undergone. A fixed effects model was used to calculate overall effect sizes. Subgroup analyses were subsequently performed. A fixed effects model was used to calculate the overall effect size. Subgroup analyses were then performed.

RESULTS

Seven studies with 233 patients were investigated. We found pioglitazone significantly improved hemoglobin A1c (%) in patients with T2DM and left ventricular diastolic function had an improvement tendency (weighted mean difference [WMD], 0.03; 95% confidence interval [CI], 0.01-0.05, P < .01) despite moderate heterogeneity (I2 = 66%). Subsequent subgroup analysis indicated that left ventricular diastolic function were significantly improved (WMD, 0.20; 95% CI, 0.12-0.29, P < .001) in T2DM patients whose average age < 55 after receiving pioglitazone treatment. However, in T2DM patients with mean age ≥ 55 years, there was no significant improvement of left ventricular diastolic function (WMD, 0.02; 95% CI, 0-0.04, P = .04).

CONCLUSION

Pioglitazone treatment significantly improved left ventricular diastolic function in type 2 diabetic patients with a mean age of < 55 years, but did not improve left ventricular diastolic function in patients with a mean age of ≥ 55 years.

Multi-modality cardiac imaging in the management of diabetic heart disease

Diabetic heart disease is a major healthcare problem. Patients with diabetes show an excess of death from cardiovascular causes, twice as high as the general population and those with diabetes type 1 and longer duration of the disease present with more severe cardiovascular complications. Premature coronary artery disease and heart failure are leading causes of morbidity and reduced life expectancy. Multimodality cardiac imaging, including echocardiography, cardiac computed tomography, nuclear medicine, and cardiac magnetic resonance play crucial role in the diagnosis and management of different pathologies included in the definition of diabetic heart disease. In this review we summarise the utility of multi-modality cardiac imaging in characterising ischaemic and non-ischaemic causes of diabetic heart disease and give an overview of the current clinical practice. We also describe emerging imaging techniques enabling early detection of coronary artery inflammation and the non-invasive characterisation of the atherosclerotic plaque disease. Furthermore, we discuss the role of MRI-derived techniques in studying altered myocardial metabolism linking diabetes with the development of diabetic cardiomyopathy. Finally, we discuss recent data regarding the use of artificial intelligence applied to large imaging databases and how those efforts can be utilised in the future in screening of patients with diabetes for early signs of disease.

Knowledge domain and emerging trends in diabetic cardiomyopathy: A scientometric review based on CiteSpace analysis

Objective

To review the literature related to diabetic cardiomyopathy (DCM), and investigate research hotspots and development trends of this field in the relevant studies based on CiteSpace software of text mining and visualization in scientific literature.

Methods

The relevant literature from the last 20 years was retrieved from the Web of Science (WoS) Core Collection database. After manual selection, each document record includes title, authors, year, organization, abstract, keywords, citation, descriptors, and identifiers. We imported the downloaded data into CiteSpace V (version 5.8.R2) to draw the knowledge map and conduct cooperative network analysis, cluster analysis, burst keyword analysis, and co-citation analysis.

Results

After manual screening, there were 3,547 relevant pieces of literature published in the last 18 years (from 2004 to 2021), including 2,935 articles and reviews, which contained 15,533 references, and the number was increasing year by year. The publications of DCM were dedicated by 778 authors of 512 institutions in 116 countries. The People's Republic of China dominated this field (1,117), followed by the USA (768) and Canada (176). In general, most articles were published with a focus on “oxidative stress,” “heart failure,” “diabetic cardiomyopathy,” “dysfunction,” “cardiomyopathy,” “expression,” “heart,” “mechanism,” and “insulin resistance.” Then, 10 main clusters were generated with a modularity Q of 0.6442 and a weighted mean silhouette of 0.8325 by the log-likelihood ratio (LLR) algorithm, including #0 heart failure, #1 perfused heart, #2 metabolic disease, #3 protective effect, #4 diabetic patient, #5 cardiac fibrosis, #6 vascular complication, #7 mitochondrial dynamics, #8 sarcoplasmic reticulum, and #9 zinc supplementation. The top five references with the strongest citation bursts include “Boudina and Abel”, “Jia et al.”, “Fang et al.”, “Poornima et al.”, and “Aneja et al.”.

Conclusion

The global field of DCM has expanded in the last 20 years. The People's Republic of China contributes the most. However, there is little cooperation among authors and institutions. Overall, this bibliometric study identified the hotspots in DCM research, including “stress state,” “energy metabolism,” “autophagy,” “apoptosis,” “inflammation,” “fibrosis,” “PPAR,” etc. Thus, further research focuses on these topics that may be more helpful to identify, prevent DCM and improve prophylaxis strategies to bring benefit to patients in the near future.

Diabetes and Progression of Heart Failure: The Atherosclerosis Risk In Communities (ARIC) Study

BACKGROUND

The influence of diabetes on progression from preclinical heart failure (HF) stages to overt HF is poorly understood.

OBJECTIVES

The purpose of this study was to characterize the influence of diabetes on the progression from preclinical HF stages (A or B based on the 2021 Universal Definition) to overt HF.

METHODS

We included 4,774 adults with preclinical HF (stage A [n = 1,551] or B [n = 3,223]) who attended the ARIC (Atherosclerosis Risk In Communities) study Visit 5 (2011-2013). Within each stage (A or B), we assessed the associations of diabetes and glycemic control (hemoglobin A1C [HbA1C] <7% vs ≥7%) with progression to HF, and of cross-categories of HF stages (A vs B), diabetes, and glycemic control with incident HF.

RESULTS

Among the participants (mean age 75.4 years, 58% women, 20% Black), there were 470 HF events during 8.6 years of follow-up. Stage B participants with HbA1C ≥7% experienced clinical HF at a younger age than those with controlled diabetes or without diabetes (mean age 80 years vs 83 years vs 82 years; P < 0.001). HbA1C ≥7% was more strongly associated with HF in stage B (HR: 1.83; 95% CI: 1.33-2.51) compared with stage A (HR: 1.52; 95% CI: 0.53-4.38). In cross-categories of preclinical HF stage and HbA1C, participants with stage B and HbA1C ≥7% had increased risk of HF progression compared with stage A without diabetes (HR: 7.56; 95% CI: 4.68-12.20).

CONCLUSIONS

Among older adults with preclinical HF stages, uncontrolled diabetes was associated with substantial risk of HF progression. Our results suggest that targeting diabetes early in the HF process is critical.

Patients phenotypes and cardiovascular risk in type 2 diabetes: the Jackson Heart Study

Background

Cardiovascular prognosis related to type 2 diabetes may not be adequately captured by information on comorbid conditions such as obesity and hypertension. To inform the cardiovascular prognosis among diabetic individuals, we conducted phenotyping using a clustering approach based on clinical data, echocardiographic indices and biomarkers.

Methods

We performed a cluster analysis on clinical, biochemical and echocardiographic variables from 529 Blacks with diabetes in the Jackson Heart Study. An association between identified clusters and major adverse cardiovascular events (MACE- composite of coronary heart disease, stroke, heart failure and atrial fibrillation) was assessed using Cox proportional hazards modeling.

Results

Cluster analysis separated individuals with diabetes (68% women, mean age 60 ± 10 years) into three distinct clusters (Clusters 1,2 &3 - with Cluster 3 being a hypertrophic cluster characterized by highest LV mass, levels of brain natriuretic peptide [BNP] and high-sensitivity cardiac troponin-I [hs-cTnI]). After a median 12.1 years, there were 141 cardiovascular events. Compared to Cluster1, Clusters 3 had an increased risk of cardiovascular disease (hazard ratio [HR] 1.60; 95% confidence interval [CI] 1.08, 2.37), while Cluster 2 had a similar risk of outcome (HR 1.11; 95% CI 0.73, 168).

Conclusions

Among Blacks with diabetes, cluster analysis identified three distinct echocardiographic and biomarkers phenotypes, with cluster 3 (high LV mass, high cardiac biomarkers) associated with worse outcomes, thus highlighting the prognostic value of subclinical myocardial dysfunction.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01501-z.

Biochemical mechanism underlying the pathogenesis of diabetic retinopathy and other diabetic complications in humans: the methanol-formaldehyde-formic acid hypothesis

Hyperglycemia in diabetic patients is associated with abnormally-elevated cellular glucose levels. It is hypothesized that increased cellular glucose will lead to increased formation of endogenous methanol and/or formaldehyde, both of which are then metabolically converted to formic acid. These one-carbon metabolites are known to be present naturally in humans, and their levels are increased under diabetic conditions. Mechanistically, while formaldehyde is a cross-linking agent capable of causing extensive cytotoxicity, formic acid is an inhibitor of mitochondrial cytochrome oxidase, capable of inducing histotoxic hypoxia, ATP deficiency and cytotoxicity. Chronic increase in the production and accumulation of these toxic one-carbon metabolites in diabetic patients can drive the pathogenesis of ocular as well as other diabetic complications. This hypothesis is supported by a large body of experimental and clinical observations scattered in the literature. For instance, methanol is known to have organ- and species-selective toxicities, including the characteristic ocular lesions commonly seen in humans and non-human primates, but not in rodents. Similarly, some of the diabetic complications (such as ocular lesions) also have a characteristic species-selective pattern, closely resembling methanol intoxication. Moreover, while alcohol consumption or combined use of folic acid plus vitamin B is beneficial for mitigating acute methanol toxicity in humans, their use also improves the outcomes of diabetic complications. In addition, there is also a large body of evidence from biochemical and cellular studies. Together, there is considerable experimental support for the proposed hypothesis that increased metabolic formation of toxic one-carbon metabolites in diabetic patients contributes importantly to the development of various clinical complications.

Metabolic, structural and biochemical changes in diabetes and the development of heart failure

Diabetes contributes to the development of heart failure through various metabolic, structural and biochemical changes. The presence of diabetes increases the risk for the development of cardiovascular disease (CVD), and since the introduction of cardiovascular outcome trials to test diabetic drugs, the importance of improving our understanding of the mechanisms by which diabetes increases the risk for heart failure has come under the spotlight. In addition to the coronary vasculature changes that predispose individuals with diabetes to coronary artery disease, diabetes can also lead to cardiac dysfunction independent of ischaemic heart disease. The hyperlipidaemic, hyperglycaemic and insulin resistant state of diabetes contributes to a perturbed energy metabolic milieu, whereby the heart increases its reliance on fatty acids and decreases glucose oxidative rates. In addition to changes in cardiac energy metabolism, extracellular matrix remodelling contributes to the development of cardiac fibrosis, and impairments in calcium handling result in cardiac contractile dysfunction. Lipotoxicity and glucotoxicity also contribute to impairments in vascular function, cardiac contractility, calcium signalling, oxidative stress, cardiac efficiency and lipoapoptosis. Lastly, changes in protein acetylation, protein methylation and DNA methylation contribute to a myriad of gene expression and protein activity changes. Altogether, these changes lead to decreased cardiac efficiency, increased vulnerability to an ischaemic insult and increased risk for the development of heart failure. This review explores the above mechanisms and the way in which they contribute to cardiac dysfunction in diabetes.

MOTS-c and Exercise Restore Cardiac Function by Activating of NRG1-ErbB Signaling in Diabetic Rats

Pathologic cardiac remodeling and dysfunction are the most common complications of type 2 diabetes. Physical exercise is important in inhibiting myocardial pathologic remodeling and restoring cardiac function in diabetes. The mitochondrial-derived peptide MOTS-c has exercise-like effects by improving insulin resistance, combatting hyperglycemia, and reducing lipid accumulation. We investigated the effects and transcriptomic profiling of MOTS-c and aerobic exercise on cardiac properties in a rat model of type 2 diabetes which was induced by feeding a high fat high sugar diet combined with an injection of a low dose of streptozotocin. Both aerobic exercise and MOTS-c treatment reduced abnormalities in cardiac structure and function. Transcriptomic function enrichment analysis revealed that MOTS-c had exercise-like effects on inflammation, myocardial apoptosis, angiogenesis and endothelial cell proliferation and migration, and showed that the NRG1-ErbB4 pathway might be an important component in both MOTS-c and exercise induced attenuation of cardiac dysfunction in diabetes. Moreover, our findings suggest that MOTS-c activates NRG1-ErbB4 signaling and mimics exercise-induced cardio-protection in diabetes.

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.

Association of triglyceride-glucose with cardiac hemodynamics in type 2 diabetes

PURPOSE

Triglyceride-glucose (TyG) index is a reliable and inexpensive alternative indicator of insulin resistance. Previous studies have shown that elevated TyG index increases the risk of diabetes, coronary heart disease, and other diseases, but the relationship between TyG index and cardiac hemodynamics in patients with type 2 diabetes mellitus (T2DM) is not clear. This study was conducted in patients with T2DM to assess the relationship between TyG and cardiac hemodynamics and its predictive ability for T2DM.

METHODS

A total of 647 individuals (348 males and 299 females) were enrolled in this study, including 446 T2DM patients and 201 healthy controls. The clinical data and related laboratory variables were assessed and recorded, and TyG index was calculated. Cardiac hemodynamics was measured by echocardiography. Pearson or Spearman correlation analysis and linear regression analysis were conducted to explore the association between TyG and cardiac hemodynamics. The receiver operating characteristics (ROC) curve was used to evaluate the efficacy of TyG index in the diagnosis of T2DM.

RESULTS

Compared with healthy controls, the systolic blood pressure (SBP), body weight, body mass index (BMI), waist circumference (WC), hip circumference (HC), HOMA-IR, and TyG levels were higher in patients with T2DM. With the increase of TyG, the levels of left ventricular mass index (LVMI), left ventricular mass (LVM), left ventricular end diastolic diameter (LVDd), posterior wall thickness (PWT), and interventricular septum thickness (IVST) were also increased in T2DM individuals. Multivariate linear regression analysis showed that TyG was an independent determinant of LVEF, PWT, IVST, and ejection time (ET) after adjusting for confounding factors. In addition, individuals with visceral obesity had higher TyG and TyG can be used as a predictor of T2DM with an AUC of 0.903 (95% CI:0.879-0.927).

CONCLUSIONS

The increase of TyG index is closely related to cardiac hemodynamics of T2DM patients, which is expected to be a simple and practical biological index to predict the changes of cardiac function in patients with T2DM.

The Contribution of Cardiac Fatty Acid Oxidation to Diabetic Cardiomyopathy Severity

Diabetes is a major risk factor for the development of cardiovascular disease via contributing and/or triggering significant cellular signaling and metabolic and structural alterations at the level of the heart and the whole body. The main cause of mortality and morbidity in diabetic patients is cardiovascular disease including diabetic cardiomyopathy. Therefore, understanding how diabetes increases the incidence of diabetic cardiomyopathy and how it mediates the major perturbations in cell signaling and energy metabolism should help in the development of therapeutics to prevent these perturbations. One of the significant metabolic alterations in diabetes is a marked increase in cardiac fatty acid oxidation rates and the domination of fatty acids as the major energy source in the heart. This increased reliance of the heart on fatty acids in the diabetic has a negative impact on cardiac function and structure through a number of mechanisms. It also has a detrimental effect on cardiac efficiency and worsens the energy status in diabetes, mainly through inhibiting cardiac glucose oxidation. Furthermore, accelerated cardiac fatty acid oxidation rates in diabetes also make the heart more vulnerable to ischemic injury. In this review, we discuss how cardiac energy metabolism is altered in diabetic cardiomyopathy and the impact of cardiac insulin resistance on the contribution of glucose and fatty acid to overall cardiac ATP production and cardiac efficiency. Furthermore, how diabetes influences the susceptibility of the myocardium to ischemia/reperfusion injury and the role of the changes in glucose and fatty acid oxidation in mediating these effects are also discussed.

Metabolic improvement with short-term, glucagon-like peptide-1 receptor agonist treatment does not improve cardiac diastolic dysfunction in patients with type 2 diabetes: A randomized, double-blind, placebo-controlled trial

AIM

To investigate if short-term treatment with liraglutide, a glucagon-like peptide-1 receptor agonist, improves left ventricular diastolic function.

MATERIALS AND METHODS

An investigator-initiated, double-blind, randomized, placebo-controlled trial on the effect of 18 weeks of treatment with liraglutide on diastolic function was assessed in patients with type 2 diabetes with signs of diastolic dysfunction (echo-Doppler determined E/e' ≥ 9 and/or lateral e' ≤ 10 cm/s). Primary outcomes were improved left ventricle filling (the early peak filling rate [ePFR]) and left atrium ease of emptying (the passive emptying fraction [LA_PEF ]), assessed by cardiac magnetic resonance imaging at rest and during chronotropic stress. Secondary outcomes included left ventricular and left atrial volumes and systolic function, measures of aortic stiffness and echocardiographic diastolic variables.

RESULTS

Forty patients were randomized to liraglutide subcutaneously 1.8 mg/day (n = 20) or placebo (n = 20). Liraglutide reduced HbA1c (-0.47%, 95% CI [-0.88% to -0.06%] [-5.1, 95% CI {-9.7 to -0.62} mmol/mol]) and weight (-2.9, 95% CI [-4.6 to -1.2] kg); both P < .03. Liraglutide did not change ePFR at rest (-24 ± 60 vs. -6 ± 46 mL/s), during stress (2 ± 58 vs. -2 ± 38 mL/s), or the changes from rest to stress (12.9 ± 72.5 vs. 4.7 ± 104.0; all P > .05). LA_PEF decreased with liraglutide during stress (-3.1% [-9.0%, 1.1%] vs. 1.0% [-2.9%, 6.1%]; P = .049), but no changes were evident at rest (-4.3% [-7.9%, 1.9%] vs. -0.6% [-3.1%, 2.2%]; P = .19), or for the changes from rest to stress (-1.7 ± 8.4 vs. 0.8 ± 8.2; P = .4). Secondary outcomes were unchanged by liraglutide.

CONCLUSIONS

Short-term treatment with liraglutide did not improve left ventricular diastolic function, suggesting the cardioprotective effect is not exerted through the improvement in diastolic dysfunction.

Cardioprotective properties of glucagon-like peptide-1 receptor agonists in type 2 diabetes mellitus patients: A systematic review

BACKGROUND AND AIMS

Cardiovascular disease is one of the main contributors for the mortality in type 2 diabetes mellitus (T2DM) patients. Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) had shown cardiovascular benefits which may be advantageous to reduce mortality in T2DM patients. This systematic review focused on analyzing the effects of GLP-1 RAs on cardiovascular outcomes.

METHODS

We conducted an extensive search through JSTOR, PubMed, Scopus, EBSCohost, and CENTRAL. All related studies assessing the use of GLP-1 RAs in T2DM patients from inception up to October 2020 were screened. Any cardioprotective properties as the outcomes were obtained.

RESULTS

A total of six studies (4 randomized, 2 observational) with a total of 182.205 patients were included in this review. The GLP-1 RAs used were either liraglutide or exenatide in combination with antihypertensive or antilipidemic drugs. All studies showed that GLP-1 RA significantly caused weight loss and improved cardiac functional capacity by increasing left ventricular ejection fraction and reducing end-systolic and end-diastolic left ventricle volume. GLP-1 RA also improved myocardial blood flow without affecting myocardial glucose uptake. However, GLP-1 RA failed to show its effect in reducing blood pressure and improving lipid profiles.

CONCLUSIONS

Despite the limited number of studies, consistent data showed that GLP-1 RA has several cardioprotective properties.

Bilateral Internal Thoracic Artery Grafting Improves Survival for Severe Left Ventricular Dysfunction and Diabetes

BACKGROUND

In patients with severe left ventricular (LV) dysfunction requiring coronary artery bypass grafting (CABG), the association between diabetic status and outcomes after surgery, as well as with survival benefit following bilateral internal thoracic artery (ITA) grafting, remain largely unknown.Methods and Results:Patients (n=188; mean [±SD] age 67±9 years) with LV ejection fraction ≤40% who underwent isolated initial CABG were classified into non-diabetic (n=64), non-insulin-dependent diabetic (NIDM; n=74), and insulin-dependent diabetic (IDM; n=50) groups. During follow-up (mean [±SD] 68±47 months), the 5-year survival rate was 84% and 65% among non-diabetic and diabetic patients, respectively (P=0.034). After adjusting for all covariates, both NIDM and IDM were associated with increased mortality, with hazard ratios (HRs) of 1.9 (95% confidence interval [CI] 1.0-3.7; P=0.049) and 2.4 (95% CI 1.2-4.8; P=0.016), respectively. Among non-diabetic patients, there was no difference in the 5-year survival rate between single and bilateral ITA grafting (86% vs. 80%, respectively; P=0.95), whereas bilateral ITA grafting increased survival among diabetic patients (57% vs. 81%; P=0.004). Multivariate analysis revealed that bilateral ITA was significantly associated with a decreased risk of mortality (HR 0.3; 95% CI 0.1-0.8; P=0.024).

CONCLUSIONS

NIDM and IDM were significantly associated with worse long-term clinical outcome after CABG for severe LV dysfunction. Bilateral ITA grafting has the potential to improve survival in diabetic patients with severe LV dysfunction.

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.

Association of prediabetes with impaired left atrial contractility in patients with never-treated hypertension

AIM

Prediabetes defined by HbA1c 5.7-6.4 has been shown to be associated with left ventricular (LV) hypertrophy and diastolic dysfunction in hypertensive patients. We hypothesized HbA1c prediabetes may be related to the alterations of LA contractility or volume in nondiabetic hypertension.

METHODS

Nondiabetic individuals on sinus rhythm were enrolled; 107 patients with never-treated hypertension, 134 patients with treated hypertension, and 71 normotensive subjects. Participants were classified as normal glucose tolerance (NGT, HbA1c<5.7), prediabetes (HbA1c 5.7-6.4) according to the ADA criteria. They underwent echocardiography to measure left atrial (LA) phasic volumes and functions, as well as mitral E/e' and mitral e'.

RESULTS

In nondiabetic patients with never-treated hypertension, prediabetes saw lower LA total emptying fraction (53.7 ± 8.2 vs. 48.3 ± 9.9*) and mitral e' (7.38 ± 2.18 vs. 6.17 ± 1.50*) than NGT, implicating that the association of prediabetes with reduced LA contractility and LV stiffness. On the other hand, in nondiabetic patients with treated hypertension, prediabetes saw higher maximum LA volume/BSA (29.7 ± 7.1 vs. 32.9 ± 6.2* ml/mm²) and mitral E/e' (10.72 ± 3.08 vs. 12.37 ± 3.35*) than NGT, suggesting the relationship of prediabetes with increased LA preload.

CONCLUSION

Prediabetes may be involved in the progression of LA structural and functional alterations in nondiabetic hypertensive patients.

Observational study investigating the prevalence of asymptomatic stage B heart failure in patients with type 2 diabetes who are not known to have coronary artery disease

OBJECTIVE

To identify the prevalence of stage B heart failure (SBHF) in patients with type 2 diabetes mellitus (T2DM) with no history of cardiovascular disease (CVD).

DESIGN

Observational study.

SETTING

A single-centre study in which eligible patients were recruited from T2DM clinic. Following consent, patients completed a questionnaire and underwent physical examinations. Patients had blood drawn for laboratory investigations and had a transthoracic echocardiography.

PARTICIPANTS

A total of 305 patients who were not known to have CVD were recruited. Patients with deranged liver function tests and end stage renal failure were excluded.

MAIN OUTCOME MEASURES

Echocardiographic parameters such as left ventricular ejection fraction, left ventricular mass index (LVMI), left ventricular hypertrophy, left atrial enlargement and diastolic function were examined.

RESULTS

A total of 305 patients predominantly females (65%), with mean body mass index of 27.5 kg/m² participated in this study. None of them had either a history or signs and symptoms of CVD. Seventy-seven percent of patients had a history of hypertension and 83% of this study population had T2DM for more than 10 years. Mean HbA1c of 8.3% was recorded. Almost all patients were taking metformin. Approximately, 40% of patients were on newer anti-T2DM agents such as sodium-glucose cotransporter-2 and dipeptidyl peptidase 4 inhibitors. Fifty-seven percent (n=174) of the study population had SBHF at the time of study: diastolic dysfunction, increased LVMI and increased left atrial volume index (LAVI) were noted in 51 patients (17%), 128 patients (42%) and 98 patients (32%), respectively. Thirty-seven patients (12%) had both increase LVMI and LAVI.

CONCLUSION

Our study has revealed a high prevalence of SBHF in T2DM patients without overt cardiac disease in Malaysia that has one of the highest prevalence of TDM in the world.

Left atrial strain and diastolic function abnormalities in obese and type 2 diabetic adolescents and young adults

Background

Adults with obesity and type 2 diabetes mellitus (T2DM) related to obesity are at increased risk of heart failure with preserved ejection fraction (HFpEF). Whether left ventricular (LV) diastolic function abnormalities related to obesity and T2DM start in adolescence and early adulthood is unknown. We non-invasively evaluated the differences seen in LV diastolic and left atrial (LA) function in adolescents and young adults with obesity and T2DM.

Methods

We analyzed echocardiographic measures of LV diastolic function in patients with structurally normal hearts which were divided into 3 groups (normal weight, obese, and T2DM). Spectral and tissue Doppler and 2-D speckle tracking measurements of diastolic function were obtained. Logistic regression was performed to compare the prevalence of abnormalities in diastolic function based on the worst 25th percentile for each measure to determine the prevalence of diastolic and LA function abnormalities in obese and T2DM patients.

Results

331 teenagers and young adults (median age 22.1 years) were analyzed (101 normal weight, 114 obese, 116 T2DM). Obese and T2DM group had lower E/A and higher E/e′. Obese and T2DM patients had significantly lower atrial reservoir, conduit, and booster strain and worse reservoir and conduit strain rate compared to normal patients (p < 0.001 for all measures). All patients had normal LA volumes. On multivariable analysis, conduit strain and reservoir and conduit strain rate were independently associated with having below the 25th percentile e′. Conduit strain rate was independently associated with having below the 25th percentile for mitral E/A ratio on multivariable analysis.

Conclusions

Abnormal indices of LV diastolic function are detected in adolescents and young adults with obesity and T2DM. LA function and strain analysis were able to detect evidence of decreased reservoir, conduit, and booster strain in these patients although LA volume was normal. The use of LA function strain may increase our ability to detect early diastolic function abnormalities in this population.

Diabetes and Heart Failure: Is it Hyperglycemia or Hyperinsulinemia?

The cardiac effects of exogenously administered insulin for the treatment of diabetes (DM) have recently attracted much attention. In particular, it has been questioned whether insulin is the appropriate treatment for patients with type 2 diabetes mellitus and heart failure. While several old and some new studies suggested that insulin treatment has beneficial effects on the heart, recent observational studies indicate associations of insulin treatment with an increased risk of developing or worsening of pre-existing heart failure and higher mortality rates. However, there is actually little evidence that the associations of insulin administration with any adverse outcomes are causal. On the other hand, insulin clearly causes weight gain and may also cause serious episodes of hypoglycemia. Moreover, excess of insulin (hyperinsulinemia), as often seen with the use of injected insulin, seems to predispose to inflammation, hypertension, dyslipidemia, atherosclerosis, heart failure, and arrhythmias. Nevertheless, it should be stressed that most of the data concerning the effects of insulin on cardiac function derive from in vitro studies with isolated animal hearts. Therefore, the relevance of the findings of such studies for humans should be considered with caution. In the present review, we summarize the existing data about the potential positive and negative effects of insulin on the heart and attempt to answer the question whether any adverse effects of insulin or the consequences of hyperglycemia are more important and may provide a better explanation of the close association of DM with heart failure.

Restrictive mitral annuloplasty with or without coronary artery bypass grafting in ischemic mitral regurgitation

Aims

In patients with ischaemic mitral regurgitation (MR), the impact of mitral valve surgery with concomitant coronary artery bypass grafting (CABG) on post‐operative survival and left ventricular (LV) reverse remodelling remains unknown. Therefore, we investigated these outcomes following restrictive mitral annuloplasty (RMA) with and without CABG in those patients.

Methods and results

This study included 309 patients with chronic MR and ischaemic cardiomyopathy for whom concomitant CABG was indicated (n = 225) or not indicated (n = 84) with RMA. The primary endpoint was all cause mortality during the follow‐up, and the secondary endpoint was defined as the composite of mortality and re‐admission for heart failure. Linear mixed model was used to analyse serial echocardiographic changes in LV function. To reduce the impact of treatment bias and potential confounding in the direct comparisons between patients who underwent RMA with and those who underwent it without CABG, we established weighted Cox proportional‐hazards regression models with inverse‐probability‐of‐treatment weighting. Pre‐operatively, there were no intergroup differences in age (RMA with CABG, 67 ± 9 vs. RMA without CABG, 68 ± 11, P = 0.409) and logistic EuroSCORE II (16 ± 14 vs. 15 ± 15%, P = 0.496). The 30‐day mortalities were 2.7% and 3.6%, respectively (P = 0.67). During follow‐up with a mean duration of 72 ± 37 months (range, 5.6–179), there were 157 deaths and 105 re‐admissions for heart failure. Overall 1‐year and 5‐year survival rates were 83 ± 2% and 58 ± 3%, respectively. Patients who did not receive CABG with RMA had a significantly lower 5‐year survival rate (45% vs. 63%, P = 0.049) and freedom from adverse events defined as mortality and/or admission for heart failure (19% vs. 43%, P < 0.001) than those who did. After adjustments for clinical covariates with inverse‐probability‐of‐treatment weighting, concomitant CABG was identified as an independent protective factor for adverse events (hazard ratio: 0.53; 95% confidence interval: 0.44–0.64; P < 0.001). Along with significant MR reduction, LV function parameters changed over time after surgery in both groups, with greater improvements in patients who underwent RMA with CABG (time effect, P < 0.001; and interaction effect, P = 0.002).

Conclusions

RMA can be performed with an acceptable operative mortality, irrespective of indications for CABG. Patients with ischaemic MR for whom CABG is indicated with RMA are more likely to show better long‐term and event‐free survival and greater improvements in LV systolic function. The optimal revascularization strategy should be discussed with a heart team whenever indicated in patients with ischaemic MR; otherwise, they may miss the opportunity to benefit from concomitant CABG during subsequent RMA.

Use of a Systematic Pharmacological Methodology to Explore the Mechanism of Shengmai Powder in Treating Diabetic Cardiomyopathy

BACKGROUND Cardiovascular complications, such as diabetic cardiomyopathy (DCM), are the leading cause of death in diabetic patients. Shengmai Powder (SMP) was found to have cardioprotective effects. MATERIAL AND METHODS Based on the systematic pharmacological methodology, this research determined the genes of DCM and the known targets of SMP, predicted potential compounds and targets of SMP, constructed networks for DCM and SMP, and performed network analysis. RESULTS Five network were constructed: (1) the DCM gene PPI network; (2) the Compound-compound target network of SMP; (3) the SMP-DCM PPI network; (4) the Compound-known target network of SMP; (5) and the SMP known target-DCM PPI network. Several DCM and treatment related targets, clusters, signaling pathways, and biological processes were found. CONCLUSIONS SMP is able to regulate glycometabolism-related, lipid metabolism-related, inflammatory response-related, oxidative stress-related signaling pathways, and biological processes and targets, which suggests that SMP may have a therapeutic effect on DCM.

Visceral Fat Area, Not Subcutaneous Fat Area, is Associated with Cardiac Hemodynamics in Type 2 Diabetes

BACKGROUND

This study was conducted in patients with type 2 diabetes mellitus (T2DM) to assess the association between visceral fat area (VFA) and cardiac hemodynamics.

METHODS

A total of 568 patients with type 2 diabetes (mean age 54±12 years; 40.8% of women) were enrolled. Visceral fat area (VFA, m²) and subcutaneous fat area (SFA, m²) were evaluated by a bioelectrical impedance analyzer. Cardiac hemodynamics were measured by echocardiography, and other clinical and laboratory variables were also assessed and recorded. Patients were divided into those with VFA ≤ 100 (n=369) and those with VFA > 100 (n=199).

RESULTS

VFA, SFA, LVMI (left ventricular mass index), left atrial diameter, left ventricular diastolic diameter (LvDd), interventricular septal thickness (IVST), left ventricular systolic diameter (LvSd), and posterior wall thickness (PWT) levels in high-V groups were significantly higher than those in low-V groups. Correlation analysis showed that VFA was positively correlated with LVMI (r=0.120, p=0.004), LVM (r=0.249, p<0.0001), left atrial diameter (r=0.375, p<0.0001), aortic root diameter (r=0.243, p<0.0001), left ventricular systolic diameter (LvSd) (r=0.211, p<0.0001) and negatively correlated with LVEF (r=-0.107, p=0.011). In multivariate linear regression analysis, VFA was the strongest independent determinant of LVMI (β=0.04, p=0.016), LVEF (β=-0.01, p=0.023), and left atrial diameter (β=0.035, p<0.0001), Internal diameter of the aortic root (β=0.014, p<0.0001) and LvSd (β=0.017, p<0.0001). In addition, the VFA also better predicted cardiovascular disease risk with AUC of 0.609 (95% CI:0.563-0.656), compared with SFA, waist-hip ratio (WHR), in a statistically significant manner.

CONCLUSION

We found a significant correlation between VFA (but not SFA) and cardiac hemodynamic parameters. The VFA has advantages as a predictor of visceral obesity and is significantly associated with the development of cardiovascular risk factors (CVD) in T2DM patients.

Heart Failure and Diabetes Mellitus: Defining the Problem and Exploring the Interrelationship

Type 2 diabetes mellitus and congestive heart failure are highly prevalent diseases with significant morbidity and mortality. These 2 diseases often occur concurrently because of shared risk factors such as coronary artery disease, and also because type 2 diabetes mellitus has direct cardiotoxic effects. Type 2 diabetes mellitus likely has a causative role in the development and prognosis of patients with heart failure. Optimal prevention and treatment of type 2 diabetes mellitus and heart failure likely involves identifying and treating their shared pathophysiologic features. Novel drug therapies, such as sodium-glucose co-transporter 2 inhibitors, offer an exciting potential to better understand the relationship between type 2 diabetes mellitus and heart failure, and may prove to have beneficial effects on cardiovascular outcomes in patients affected by these diseases.

Depressed systemic arterial compliance and impaired left ventricular midwall performance in aortic stenosis with concomitant type 2 diabetes: a retrospective cross-sectional study

Background

Degenerative aortic stenosis (AS), a disease of the elderly, frequently coexists with concomitant diseases, including type 2 diabetes (T2DM) which amplifies the cardiovascular (CV) risk. T2DM affects left ventricular (LV) structure and function via hemodynamic and metabolic factors. In concentric LV geometry, typical for AS, indices of LV midwall mechanics are better estimates of LV function than ejection fraction (EF). Effects of T2DM coexisting with AS on circumferential LV midwall systolic function and large artery properties have not been reported so far. Our aim was to compare characteristics of AS patients with and without T2DM, with a focus on LV midwall systolic function and arterial compliance.

Methods

Medical records of 130 electively hospitalized patients with moderate or severe isolated degenerative AS were retrospectively analyzed. Exclusion criteria included clinical instability, atrial fibrillation, coronary artery disease and relevant non-cardiac diseases. From in-hospital echocardiography and blood pressure, we calculated LV midwall fractional shortening (mwFS), circumferential end-systolic LV wall stress (cESS) and valvulo-arterial impedance (Zva), estimates of LV afterload, as well as systemic arterial compliance.

Results

Patients with (n = 50) and without T2DM (n = 80) did not differ in age, AS severity, LV mass and LV diastolic diameter. T2DM patients exhibited elevated cESS (247 ± 105 vs. 209 ± 84 hPa, p = 0.025) and Zva (5.8 ± 2.2 vs. 5.1 ± 1.8 mmHg per mL/m², p = 0.04), and lower stroke volume index (33 ± 10 vs. 38 ± 12 mL/m², p = 0.01) and systemic arterial compliance (0.53 ± 0.16 vs. 0.62 ± 0.22 mL/m² per mmHg, p = 0.01). mwFS (11.9 ± 3.9 vs. 14.1 ± 3.7%, p = 0.001), but not EF (51 ± 14 vs. 54 ± 13%, p = n.s.), was reduced in T2DM. mwFS and cESS were inversely interrelated in patients both with (r = − 0.59, p < 0.001) and without T2DM (r = − 0.53, p < 0.001) By multiple regression, higher cESS (p < 0.001) and T2DM (p = 0.02) were independent predictors of depressed mwFS.

Conclusions

In AS, coexistent T2DM appears associated with reduced systemic arterial compliance and LV dysfunction at the midwall level, corresponding to slightly depressed myocardial contractility.

Electronic supplementary material

The online version of this article (10.1186/s12933-019-0894-1) contains supplementary material, which is available to authorized users.

Effects of Different Antidiabetic Medications on Endothelial Glycocalyx, Myocardial Function, and Vascular Function in Type 2 Diabetic Patients: One Year Follow-Up Study

Background: Poor glycaemic control affects myocardial function. We investigated changes in endothelial function and left ventricular (LV) myocardial deformation in poorly controlled type 2 diabetics before and after glycaemic control intensification. Methods: In 100 poorly-controlled diabetic patients (age: 51 ± 12 years), we measured at baseline and at 12 months after intensified glycaemic control: (a) Pulse wave velocity (PWV, Complior); (b) flow-mediated dilatation (FMD, %) of the brachial artery; (c) perfused boundary region (PBR) of the sublingual arterial micro-vessels (side-view dark-field imaging, Glycocheck); (d) LV global longitudinal strain (GLS), peak twisting (pTw), peak twisting velocity (pTwVel), and peak untwisting velocity (pUtwVel) using speckle tracking echocardiography, where the ratio of PWV/GLS was used as a marker of ventricular-arterial interaction; and (e) Malondialdehyde (MDA) and protein carbonyls (PCs) plasma levels. Results: Intensified 12-month antidiabetic treatment reduced HbA1c (8.9 ± 1.8% (74 ± 24 mmol/mol) versus 7.1 ± 1.2% (54 ± 14 mmol/mol), p = 0.001), PWV (12 ± 3 versus 10.8 ± 2 m/s), PBR (2.12 ± 0.3 versus 1.98 ± 0.2 μm), MDA, and PCs; meanwhile, the treatment improved GLS (−15.2 versus −16.9%), PWV/GLS, and FMD% (p < 0.05). By multi-variate analysis, incretin-based agents were associated with improved PWV (p = 0.029), GLS (p = 0.037), PBR (p = 0.047), and FMD% (p = 0.034), in addition to a reduction of HbA1c. The patients with a final HbA1c ≤ 7% (≤ 53 mmol/mol) had greater reduction in PWV, PBR, and markers of oxidative stress, with a parallel increase in FMD and GLS, compared to those who had HbA1c > 7% (> 53 mmol/mol). Conclusions: Intensified glycaemic control, in addition to incretin-based treatment, improves arterial stiffness, endothelial glycocalyx, and myocardial deformation in type 2 diabetes after one year of treatment.

Effect of liraglutide on cardiac function in patients with type 2 diabetes mellitus: randomized placebo-controlled trial

Background

Liraglutide is an antidiabetic agent with cardioprotective effect. The purpose of this study is to test efficacy of liraglutide to improve diabetic cardiomyopathy in patients with diabetes mellitus type 2 (DM2) without cardiovascular disease.

Methods

Patients with DM2 were randomly assigned to receive liraglutide 1.8 mg/day or placebo in this double-blind trial of 26 weeks. Primary outcome measures were LV diastolic function (early (E) and late (A) transmitral peak flow rate, E/A ratio, early deceleration peak (Edec), early peak mitral annular septal tissue velocity (Ea) and estimated LV filling pressure (E/Ea), and systolic function (stroke volume, ejection fraction, cardiac output, cardiac index and peak ejection rate) assessed with CMR. Intention-to-treat analysis of between-group differences was performed using ANCOVA. Mean estimated treatment differences (95% confidence intervals) are reported.

Results

23 patients were randomized to liraglutide and 26 to placebo. As compared with placebo, liraglutide significantly reduced E (− 56 mL/s (− 91 to − 21)), E/A ratio (− 0.17 (− 0.27 to − 0.06)), Edec (− 0.9 mL/s² * 10⁻³ (− 1.3 to − 0.2)) and E/Ea (− 1.8 (− 3.0 to − 0.6)), without affecting A (3 mL/s (− 35 to 41)) and Ea (0.4 cm/s (− 0.9 to 1.4)). Liraglutide reduced stroke volume (− 9 mL (− 16 to − 2)) and ejection fraction (− 3% (− 6 to − 0.1)), but did not change cardiac output (− 0.4 L/min (− 0.9 to 0.2)), cardiac index (− 0.1 L/min/m² (− 0.4 to 0.1)) and peak ejection rate (− 46 mL/s (− 95 to 3)).

Conclusions

Liraglutide reduced early LV diastolic filling and LV filling pressure, thereby unloading the left ventricle. LV systolic function reduced and remained within normal range. Future studies are needed to investigate if liraglutide-induced left ventricular unloading slows progression of diabetic cardiomyopathy into symptomatic stages.

Trial registration ClinicalTrials.gov: NCT01761318.

[Type 2 Diabetes Mellitus and Heart Failure: Innovative Possibilities for Management of Prognosis]

Type 2 diabetes mellitus (T2DM) has gone beyond the professional interests of one specialty. T2DM, cardiovascular (CV) diseases and chronic kidney disease, considered from the standpoint of a single cardio-reno-metabolic continuum, place a heavy economic burden on society. At the same time, the improvement of diagnostic methods and medical technologies led to distinct decrease in the frequency and mortality from a number of complications of T2DM, including myocardial infarction and stroke, but other states took their place. Thus, heart failure (HF) has taken the position of one of the most frequent complications with average prevalence of 24-40 % and significant predominance of HF with preserved ejection fraction (HFpEF). According to this paradigm, HFpEF is not a disease of diastolic dysfunction, but a systemic disease, the central element of which is impaired renal function. All this together has a potential value for choosing the optimal therapy. In recent years the results of specially designed studies assessing the CV-safety of antidiabetic drugs from the groups of dipeptidyl peptidase-4 (DPP4) inhibitors, glucagon-like preptide-1 (GLP-1) receptor agonists and sodium - glucose co-transporter-2 (SGLT2) inhibitors have become known. These drugs, except for SGLT2 inhibitors, by their mechanism of action affecting insulin resistance and hyperglycemia, demonstrated neutral or negative result on the frequency of hospitalizations due to HF. The EMPA-REG OUTCOME study with SGLT2, which has a special insulin-independent mechanism of action, demonstrated not only the efficacy and CV-safety of the drug in the form of a decrease in CV mortality by 38 %, but also a decrease in hospitalizations for HF by 35 %. Further studies with SGLT2 inhibitors confirmed positive effect on HF, indicating a class effect of the drugs. The recently completed study DECLARE-TIMI 58 proved the advantages of using dapagliflozin for the primary and secondary prevention of HF. This review highlights the prevalence of HF in diabetes mellitus, a new concept of the pathophysiology of HF, the main groups of sugar-lowering drugs and their effect on CV outcomes, in particular on HF.

Diabetic cardiomyopathy - A comprehensive updated review

Diabetes causes cardiomyopathy and increases the risk of heart failure independent of hypertension and coronary heart disease. This condition called "Diabetic Cardiomyopathy" (DCM) is becoming a well- known clinical entity. Recently, there has been substantial research exploring its molecular mechanisms, structural and functional changes, and possible development of therapeutic approaches for the prevention and treatment of DCM. This review summarizes the recent advancements to better understand fundamental molecular abnormalities that promote this cardiomyopathy and novel therapies for future research. Additionally, different diagnostic modalities, up to date screening tests to guide clinicians with early diagnosis and available current treatment options has been outlined.

Evaluation of tissue Doppler ultrasonographic and strain imaging for assessment of myocardial dysfunction in dogs with type 1 diabetes mellitus

OBJECTIVE To investigate cardiac structural and functional changes by tissue Doppler imaging (TDI) and strain imaging in dogs with spontaneous type 1 diabetes mellitus. ANIMALS 30 client-owned dogs, of which 10 had normotensive type 1 diabetes mellitus and 20 were healthy. PROCEDURES All dogs underwent physical examination, laboratory analyses, standard echocardiography, and TDI. RESULTS On TDI and strain imaging, transmitral peak early diastolic velocity (E)-to-tissue Doppler-derived peak early diastolic velocity at basal segment (E') of septum ratio, E:lateral E' ratio, and septal tissue Doppler-derived peak late diastolic velocity at basal segment (A') were significantly higher and the septal E':A' ratio and lateral longitudinal strain were significantly lower for diabetic dogs than for control dogs. Furthermore, in diabetic dogs, serum glucose and fructosamine concentrations after a 12-hour period of food withholding were positively correlated with regional systolic functional variables (septal and lateral longitudinal strain) and left ventricular filling pressure indices (E:septal E' and E:lateral E' ratios) but were negatively correlated with diastolic functional variables (E:transmitral peak late diastolic velocity and septal and lateral E':A' ratios). CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that myocardial function in diabetic dogs may be altered before the development of clinical heart-associated signs and that the change may be more readily detected by TDI and strain imaging than by conventional echocardiography. In addition, findings indicated that hyperglycemia could have detrimental effects on myocardial function, independent of hypertension, other cardiac diseases, and left ventricular hypertrophy, in dogs with type 1 diabetes.

The E/e' ratio difference between subjects with type 2 diabetes and controls. A meta-analysis of clinical studies

Type 2 diabetes is associated with an increased risk of heart failure. Left ventricular diastolic dysfunction and type 2 diabetes are frequently associated. Using echocardiography, we know that tissue Doppler imaging E/e’ ratio is a reliable predictor of left ventricular filling pressure. We performed a systematic review and meta-analysis to investigate the averaged E/e’ ratio value in patients with type 2 diabetes compared to non-diabetic controls. In the analysis we included cross-sectional studies providing the averaged E/e’ ratio. Subgroup/sensitivity analyses were conducted according to variables known to influence E/e’ ratio measurements. The analysis included 15 cross sectional studies with 877 type 2 diabetes patients and 1193 controls. The weighted mean difference showed higher values in diabetes (WMD 2.02; 95% CI 1.35, 2.70; p<0.001). The result was consistent in the subgroup/sensitivity analyses. Visual inspection of the funnel plot did not identify substantial asymmetry and the Egger test for funnel plot asymmetry showed a p value of 0.36. In conclusion, our assessment suggests that averaged E/e’ ratio is consistently increased in patients with type 2 diabetes compared to non-diabetic controls in the absence of cardiovascular diseases and complicated hypertension. This alteration may be a precocious diastolic alteration in the diabetic cardiomyopathy.

Of mice and men: models and mechanisms of diabetic cardiomyopathy

Diabetes mellitus increases the risk of heart failure independent of co-existing hypertension and coronary artery disease. Although several molecular mechanisms for the development of diabetic cardiomyopathy have been identified, they are incompletely understood. The pathomechanisms are multifactorial and as a consequence, no causative treatment exists at this time to modulate or reverse the molecular changes contributing to accelerated cardiac dysfunction in diabetic patients. Numerous animal models have been generated, which serve as powerful tools to study the impact of type 1 and type 2 diabetes on the heart. Despite specific limitations of the models generated, they mimic various perturbations observed in the diabetic myocardium and continue to provide important mechanistic insight into the pathogenesis underlying diabetic cardiomyopathy. This article reviews recent studies in both diabetic patients and in these animal models, and discusses novel hypotheses to delineate the increased incidence of heart failure in diabetic patients.

Possibility of a New Therapeutic Strategy for Left Ventricular Dysfunction in Type 2 Diabetes

Type 2 diabetes mellitus (T2DM) substantially increases the risk of cardiovascular events, including heart failure (HF), due to complications such as hypertension, obesity and dyslipidemia based on metabolic syndrome, which plays the central pathological role in HF. A reason is that T2DM causes left ventricular (LV) diastolic dysfunction beginning in the early phase of the disease, which in turn increases the risk of development of HF independently of the control of blood glucose levels, blood pressure or the presence of coronary artery diseases. Intracellular metabolic disorders and increased oxidative stress due to hyperglycemia, increased insulin resistance and chronic inflammation are pathogenic mechanisms involved in the LV diastolic dysfunction caused by T2DM. These mechanisms lead to structural changes in the heart such as LV hypertrophy and interstitial fibrosis, resulting in HF. The prevalence of HF with preserved ejection fraction (HFpEF), the major pathology of LV diastolic dysfunction, has been increasing recently, and a high incidence of HFpEF in patients with T2DM was reported. An effective therapy has not been established for HFpEF because multiple comorbidities such as advanced age, hypertension, obesity, dyslipidemia, chronic kidney disease and atrial fibrillation as well as diabetes are involved in its pathology. In the present review, we review the involvement of associated conditions such as hypertension, obesity and advanced age from the aspect of the T2DM and LV diastolic dysfunction and discuss the possibility of the development of a new therapeutic strategy for LV diastolic dysfunction and HFpEF.

Fragmented QRS complexes are associated with left ventricular dysfunction in patients with type-2 diabetes mellitus: a two-dimensional speckle tracking echocardiography study

Background: Heart failure may develop independently of coronary artery disease in diabetes mellitus (DM) patients. Fragmented QRS (fQRS) is a marker of myocardial fibrosis or scar tissue and is related to an increase in cardiovascular adverse events. In this study, we examined the utility of speckle tracking echocardiography (STE) in assessing LV function in DM patients with fQRS. Methods and Results: The current study included 178 consecutive patients diagnosed with type-2 DM. The patients included were separated into two groups: those with (n = 50) and without (n = 128) fQRS. The two groups were compared by obtaining LV strain values with STE. Statistically significant differences were also identified between fQRS(-) and fQRS (+) groups with respect to Lv-GLS (p < .001), maxLAVI (p = .020), minLAVI (p < .001), E velocity (p < .001), Em velocity (0.002), E/Em ratio (<0.001) SRe (p < .001), SRe/SRa ratio (p < .001), SRivr (p < .001) and E/SRivr ratio (p < .001). In the multiple linear regression analysis, fQRS (β = -2.077, p = .002) and DM duration (β = -0.216, p = .021) were identified as independent predictors of Lv-GLS. However, fQRS (β = 4.557, p = .001) and minLAVI (β = -2.198, p = .031) were also found to be independent predictors of E/SRivr. We also performed multiple logistic regression analysis and identified Lv-GLS (β = -0.557, p = .001), minLAVI (β = -0.769, p = .001), E/Em ratio (β = 0.650, p = .001) and E/SRivr (β = 0.105, p = .001) as independent predictors of fQRS. Conclusıons: The results of this study revealed that subclinical LV dysfunction was more common in diabetic patients with fQRS. Therefore, determination of fQRS could be an indicator of the diabetic CMP in patients with DM.

Prevalence and distribution of left ventricular diastolic dysfunction in treated patients with long-lasting hypertension

BACKGROUND

Although the presence of sub-clinical left ventricular diastolic dysfunction (LVDD) increases cardiovascular risk, the current ESH/ESC guidelines do not include the presence of this condition in the list of target organ damage or cardiovascular risk charts dedicated to the hypertensive population. Several conditions may predict the LVDD occurrence, however, clustering of these factors with hypertension makes the relationship less clear. Therefore, the aim of this study was to evaluate both the occurrence and the severity of diastolic dysfunction in a large cohort of treated hypertensives.

METHODS

We retrospectively analyzed records of 610 hypertensive participants of the CARE NORTH Study who consented to echocardiography and were free of overt cardiovascular disease. Mean age was 54.0 ± 13.9 years (mean ± SD), BMI 29.7 ± 4.8 kg/m². The exclusion criteria were: established heart failure, LVEF <45%, coronary revascularization, valvular defect, atrial fibrillation, or stroke. The staging of LVDD was based on comprehensive transthoracic echocardiographic measurements.

RESULTS

49.7% percent of the patients had normal diastolic function (38.8% vs. 59.0%, females (F) vs. males (M), respectively; p < .001). Grade 1 LVDD was documented in 24.4% (27.8% and 21.6%; F and M; p = .08) and grade 2 LVDD in 19.3% (24.9% and 14.6%; F and M; p = .001) of the patients. None were diagnosed with grade 3 LVDD. In the logistic regression model, female sex, advancing age, obesity status, established diabetes mellitus, higher 24-hour SBP, and increasing LVMI were identified as the independent variables increasing the odds for the presence of LVDD, whereas blood-lowering therapy attenuated the risk.

CONCLUSIONS

There is an unexpectedly high prevalence of different forms of diastolic dysfunction in treated hypertensive patients who are free of overt cardiovascular disease.