Prevalence and clinical characteristics of diabetic cardiomyopathy in patients with acute heart failure

BACKGROUND AND AIMS

Diabetic cardiomyopathy refers to cases of diabetes mellitus (DM) complicated by cardiac dysfunction in the absence of cardiovascular disease and hypertension. Its epidemiology remains unclear due to the high rate of coexistence between DM and hypertension. Therefore, this study aimed to examine the prevalence and clinical characteristics of diabetic cardiomyopathy among patients with acute heart failure (HF).

METHODS AND RESULTS

This multicenter, retrospective study included 17,614 consecutive patients with acute HF. DM-related HF was defined as HF complicating DM without known manifestations of coronary artery disease, significant valvular heart disease, or congenital heart disease, while diabetic cardiomyopathy was defined as DM-related HF without hypertension. Univariable and multivariable logistic regression analyses were performed to identify factors associated with in-hospital mortality. Diabetic cardiomyopathy prevalence was 1.6 % in the entire cohort, 5.2 % in patients with acute HF complicating DM, and 10 % in patients with DM-related HF. Clinical characteristics, including the presence of comorbidities, laboratory data on admission, and factors associated with in-hospital mortality, significantly differed between the diabetic cardiomyopathy group and the DM-related HF with hypertension group. The in-hospital mortality rate was significantly higher in patients with diabetic cardiomyopathy than in patients with DM-related HF with hypertension (7.7 % vs. 2.8 %, respectively; P < 0.001).

CONCLUSION

The prevalence of diabetic cardiomyopathy was 1.6 % in patients with acute HF, and patients with diabetic cardiomyopathy were at high risk for in-hospital mortality. The clinical characteristics of patients with diabetic cardiomyopathy were significantly different than those of patients with DM-related HF with hypertension.

Identification of important modules and biomarkers in diabetic cardiomyopathy based on WGCNA and LASSO analysis

Background

Diabetic cardiomyopathy (DCM) lacks specific and sensitive biomarkers, and its diagnosis remains a challenge. Therefore, there is an urgent need to develop useful biomarkers to help diagnose and evaluate the prognosis of DCM. This study aims to find specific diagnostic markers for diabetic cardiomyopathy.

Methods

Two datasets (GSE106180 and GSE161827) from the GEO database were integrated to identify differentially expressed genes (DEGs) between control and type 2 diabetic cardiomyopathy. We assessed the infiltration of immune cells and used weighted coexpression network analysis (WGCNA) to construct the gene coexpression network. Then we performed a clustering analysis. Finally, a diagnostic model was built by the least absolute shrinkage and selection operator (LASSO).

Results

A total of 3066 DEGs in the GSE106180 and GSE161827 datasets. There were differences in immune cell infiltration. According to gene significance (GS) > 0.2 and module membership (MM) > 0.8, 41 yellow Module genes and 1474 turquoise Module genes were selected. Hub genes were mainly related to the "proteasomal protein catabolic process", "mitochondrial matrix" and "protein processing in endoplasmic reticulum" pathways. LASSO was used to construct a diagnostic model composed of OXCT1, CACNA2D2, BCL7B, EGLN3, GABARAP, and ACADSB and verified it in the GSE163060 and GSE175988 datasets with AUCs of 0.9333 (95% CI: 0.7801-1) and 0.96 (95% CI: 0.8861-1), respectively. H9C2 cells were verified, and the results were similar to the bioinformatics analysis.

Conclusion

We constructed a diagnostic model of DCM, and OXCT1, CACNA2D2, BCL7B, EGLN3, GABARAP, and ACADSB were potential biomarkers, which may provide new insights for improving the ability of early diagnosis and treatment of diabetic cardiomyopathy.

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.

Inhibition of the long non-coding RNA ZFAS1 attenuates ferroptosis by sponging miR-150-5p and activates CCND2 against diabetic cardiomyopathy

Diabetic cardiomyopathy (DbCM) is responsible for increased morbidity and mortality in patients with diabetes and heart failure. However, the pathogenesis of DbCM has not yet been identified. Here, we investigated the important role of lncRNA-ZFAS1 in the pathological process of DbCM, which is associated with ferroptosis. Microarray data analysis of DbCM in patients or mouse models from GEO revealed the significance of ZFAS1 and the significant downregulation of miR-150-5p and CCND2. Briefly, DbCM was established in high glucose (HG)-treated cardiomyocytes and db/db mice to form in vitro and in vivo models. Ad-ZFAS1, Ad-sh-ZFAS1, mimic miR-150-5p, Ad-CCND2 and Ad-sh-CCND2 were intracoronarily administered to the mouse model or transfected into HG-treated cardiomyocytes to determine whether ZFAS1 regulates miR-150-5p and CCND2 in ferroptosis. The effect of ZFAS1 on the left ventricular myocardial tissues of db/db mice and HG-treated cardiomyocytes, ferroptosis and apoptosis was determined by Masson staining, immunohistochemical staining, Western blotting, monobromobimane staining, immunofluorescence staining and JC-1 staining. The relationships among ZFAS1, miR-150-5p and CCND2 were evaluated using dual-luciferase reporter assays and RNA pull-down assays. Inhibition of ZFAS1 led to reduced collagen deposition, decreased cardiomyocyte apoptosis and ferroptosis, and attenuated DbCM progression. ZFAS1 sponges miR-150-5p to downregulate CCND2 expression. Ad-sh-ZFAS1, miR-150-5p mimic, and Ad-CCND2 transfection attenuated ferroptosis and DbCM development both in vitro and in vivo. However, transfection with Ad-ZFAS1 could reverse the positive effects of miR-150-5p mimic and Ad-CCND2 in vitro and in vivo. lncRNA-ZFAS1 acted as a ceRNA to sponge miR-150-5p and downregulate CCND2 to promote cardiomyocyte ferroptosis and DbCM development. Thus, ZFAS1 inhibition could be a promising therapeutic target for the treatment and prevention of DbCM.

Asymptomatic Diabetic Cardiomyopathy: an Underrecognized Entity in Type 2 Diabetes

PURPOSE OF REVIEW

Type 2 diabetes (T2D) is associated with an increased risk of heart failure (HF), with diabetic cardiomyopathy (DbCM) referring to abnormal heart structure in the absence of other driving cardiac factors such as hypertension, coronary artery disease (CAD), and valvular heart disease. Stage B DbCM is commonly asymptomatic and represents a form of stage B HF; DbCM thus represents a transitional phenotype prior to onset of symptomatic HF. The pathogenesis of DbCM is not fully elucidated but involves hyperglycemia, insulin resistance, increased free fatty acids (FFA), lipotoxicity, oxidative stress, advanced glycation end product (AGE) formation, activation of the renin-angiotensin-aldosterone system (RAAS) with an increase in angiotensin II, and dyshomeostasis of calcium, which all contribute to left ventricular hypertrophy (LVH) and cardiac systolic and diastolic dysfunction. Although DbCM is an established pathogenic process, it is underrecognized clinically due to its commonly asymptomatic nature. Raising awareness to identify high-risk individuals with stage B HF due to DbCM, who may subsequently progress to overt HF (stage C/D HF), as well as identifying new pharmacological agents and approaches to prevent functional decline, may help reduce this global health problem. The aim of this review is to focus on stage B DbCM; provide data on diagnostic approaches, current therapies, and potential therapies under investigation; and highlight the need to raise awareness and interdisciplinary dialogue among clinicians and researchers.

RECENT FINDINGS

There are no currently approved therapeutic strategies to treat or prevent progression of stage B DbCM, but multiple attempts are being made to target different pathogenic mechanisms involved in the development of DbCM. Recent cardiovascular (CV) outcome trials (CVOTs) have identified newer therapeutic agents with CV benefit, such as sodium-glucose cotransporter-2 (SGLT-2) inhibitors that reduce hospitalization for HF and glucagon-like peptide-1 (GLP-1) receptor agonists that reduce major adverse CV events (MACE), though without consistent effect on HF outcomes. Recent clinical practice guidelines recommend screening patients at high risk for HF. Further definition and interdisciplinary discussion of high-yield populations to screen, appropriate subsequent evaluation and intervention are needed to advance this area. DbCM is a complex entity that results from multiple pathogenic mechanisms triggered by impairment of glucose and lipid metabolism over many years. DbCM is commonly asymptomatic and represents a form of stage B HF. It is an underrecognized process that may progress to functional decline and overt HF. Although newer medications approved for the treatment of T2D may play an important role in reducing the risk of HF complications, less focus has been placed on earlier recognition and treatment of DbCM while asymptomatic. Additional efforts should be made to further study and target this stage in order to decrease the overall burden of HF.

Circulating long chain acylcarnitines and outcomes in diabetic heart failure: an HF-ACTION clinical trial substudy

BACKGROUND

Whether differences in circulating long chain acylcarnitines (LCAC) are seen in heart failure (HF) patients with and without diabetes mellitus (DM), and whether these biomarkers report on exercise capacity and clinical outcomes, remains unknown. The objective of the current study was to use metabolomic profiling to identify biomarkers that report on exercise capacity, clinical outcomes, and differential response to exercise in HF patients with and without DM.

METHODS

Targeted mass spectrometry was used to quantify metabolites in plasma from participants in the heart failure: a controlled trial investigating outcomes of exercise training (HF-ACTION) trial. Principal components analysis was used to identify 12 uncorrelated factors. The association between metabolite factors, diabetes status, exercise capacity, and time to the primary clinical outcome of all-cause mortality or all-cause hospitalization was assessed.

RESULTS

A total of 664 participants were included: 359 (54%) with DM. LCAC factor levels were associated with baseline exercise capacity as measured by peak oxygen consumption (beta 0.86, p  =  2 × 10-7, and were differentially associated in participants with and without DM (beta 1.58, p  =  8  ×  10-8 vs. 0.67, p  =  9  ×  10-4, respectively; p value for interaction  =  0.012). LCAC levels changed to a lesser extent in participants with DM after exercise (mean ∆ 0.09, p  =  0.24) than in those without DM (mean ∆ 0.16, p  =  0.08). In univariate and multivariate modeling, LCAC factor levels were associated with time to the primary outcome (multivariate HR 0.80, p  =  2.74  ×  10-8), and were more strongly linked to outcomes in diabetic participants (HR 0.64, p  =  3.21  ×  10-9 v. HR 0.90, p  =  0.104, p value for interaction  =  0.001). When analysis was performed at the level of individual metabolites, C16, C16:1, C18, and C18:1 had the greatest associations with both exercise capacity and outcomes, with higher levels associated with worse outcomes. Similar associations with time to the primary clinical outcome were not found in a control group of patients without HF from the CATHeterization GENetics (CATHGEN) study.

CONCLUSIONS

LCAC biomarkers are associated with exercise status and clinical outcomes differentially in HF patients with and without DM. Impaired fatty acid substrate utilization and mitochondrial dysfunction both at the level of the skeletal muscle and the myocardium may explain the decreased exercise capacity, attenuated response to exercise training, and poor clinical outcomes seen in patients with HF and DM. Trial Registration clinicaltrials.gov Identifier: NCT00047437.

Association of the Non-Alcoholic Fatty Liver Disease Fibrosis Score with subclinical myocardial remodeling in patients with type 2 diabetes: A cross-sectional study in China

AIMS/INTRODUCTION

Non-alcoholic fatty liver disease, especially with liver fibrosis, is associated with cardiovascular diseases. The Non-Alcoholic Fatty Liver Disease Fibrosis Score (NFS), a non-invasive marker of advanced fibrosis, was found to be associated with cardiovascular diseases in different populations. The aim of the present study was to determine whether the NFS is associated with subclinical myocardial remodeling in type 2 diabetes patients.

MATERIALS AND METHODS

A cross-sectional study was carried out in type 2 diabetes patients. The NFS derived from available parameters was calculated, and the participants were divided according to the quartiles of the NFS and grades of the NFS (low, intermediate and high). Fibrosis-4 and Aspartate Aminotransferase to Platelet Ratio Index, another two liver fibrosis scores, were also calculated. Subclinical myocardial remodeling was examined by echocardiography, and its associations with NFS, Fibrosis-4 and Aspartate Aminotransferase to Platelet Ratio Index were analyzed.

RESULTS

A total of 1,878 type 2 diabetes patients were enrolled in the present study. The NFS was independently associated with sex, age, body mass index, low-density lipoprotein cholesterol and glycated hemoglobin in type 2 diabetes patients. Parameters of subclinical myocardial remodeling including left atrial dimension, interventricular septum thickness, left ventricular end-diastolic diameter, left ventricular end-systolic diameter, left ventricular posterior wall thickness (LVPWT) and left ventricular mass index were all gradually increased with the increment of the NFS. Linear regression analysis further showed that the NFS was positively associated with left atrial dimension, interventricular septum thickness, left ventricular end-diastolic diameter, left ventricular end-systolic diameter, LVPWT and left ventricular mass index after adjustment for the confounding factors. Similarly, Fibrosis-4 was associated with left atrial dimension, interventricular septum thickness, LVPWT and left ventricular mass index. In contrast, the Aspartate Aminotransferase to Platelet Ratio Index was only associated with LVPWT.

CONCLUSIONS

Non-invasive liver fibrosis scores, especially the NFS, are independently associated with subclinical myocardial remodeling in type 2 diabetes patients.

Paradoxical effect of fat diet in matrix metalloproteinases induced mitochondrial dysfunction in diabetic cardiomyopathy

AIMS

Diabetic cardiomyopathy represents the main cause of death among diabetic people. Despite this evidence, the molecular mechanisms triggered by impaired glucose and lipid metabolism inducing heart damage remain unclear. The aim of our study was to investigate the effect of altered metabolism on the early stages of cardiac injury in experimental diabetes.

METHODS

For this purpose, rats were fed a normocaloric diet (NPD) or a high fat diet (HFD) for up to 12 weeks. After the fourth week, streptozocin (35 mg/kg) was administered in a subgroup of both NPD and HFD rats to induce diabetes. Cardiac function was analysed by echocardiography. Matrix metalloproteinases (MMPs) activity and intracellular localization were assessed through zymography and immunofluorescence, whereas apoptotic and oxidative markers by immunohistochemistry and western blot.

RESULTS

Hyperglycaemia or hyperlipidaemia reduced ejection fraction and fractional shortening as compared with control. Unexpectedly, cardiac dysfunction was less marked in diabetic rats fed a hyperlipidaemic diet, suggesting an adaptive response of the myocardium to hyperglycaemia-induced injury. This response was characterized by the inhibition of N-terminal truncated-MMP-2 translocation from endoplasmic reticulum into mitochondria and by superoxide anion overproduction observed in cardiomyocytes under hyperglycaemia.

CONCLUSION

Overall, these findings suggest novel therapeutic targets aimed to counteract mitochondrial dysfunction in the onset of diabetic cardiomyopathy.

Left atrial function in diabetes: does it help?

Left atrial (LA) structural, functional and mechanical changes have important role in development of diabetic cardiomyopathy and it was discovered that LA remodeling has important prognostic role in the patients with diabetes (DM). Previously the focus of echocardiographic studies in DM population was on the left ventricular structure and function, but the atrioventricular coupling was proved to be one of the main predictors of cardiovascular morbidity and mortality in DM patients. Each phase of LA cycle has determinant role in the atrioventricular coupling and therefore the accurate assessment of LA phasic function gained importance over last decade. The failure of any of the three LA phasic functions (reservoir, conduit or contractile) leads potentially to LA dilatation, left ventricular diastolic dysfunction, atrial fibrillation and ultimately development of heart failure with preserved (or even reduced) ejection fraction. Even though LA phasic function has not been extensively studied in DM population, it is reasonable to hypothesize that LA dysfunction is very frequent in these patients, considering the high prevalence of atrial fibrillation and heart failure in these individuals. In research and clinical purposes two techniques have been used for determination of LA phasic function: volumetric and strain. Although these methods fundamentally differ, with their own advantages and limitations, they also provide comparable results that can direct our therapeutic approach in DM patients. Namely, not only that LA function represents an independent predictor of cardiovascular outcome in DM patients, but also it has been also associated with parameters of glycemic control. This review summarized the current knowledge regarding LA phasic function in DM patients.

Skin autofluorescence predicts new cardiovascular disease and mortality in people with type 2 diabetes

BACKGROUND

Skin autofluorescence (SAF) is a non-invasive marker of tissue accumulation of advanced glycation endproducts (AGE). Recently, we demonstrated in the general population that elevated SAF levels predict the development of type 2 diabetes (T2D), cardiovascular disease (CVD) and mortality. We evaluated whether elevated SAF may predict the development of CVD and mortality in individuals with T2D.

METHODS

We included 2349 people with T2D, available baseline SAF measurements (measured with the AGE reader) and follow-up data from the Lifelines Cohort Study. Of them, 2071 had no clinical CVD at baseline. 60% were already diagnosed with diabetes (median duration 5, IQR 2-9 years), while 40% were detected during the baseline examination by elevated fasting blood glucose ≥7.0 mmol/l) and/or HbA1c ≥6.5% (48 mmol/mol).

RESULTS

Mean (±SD) age was 57 ± 12 yrs., BMI 30.2 ± 5.4 kg/m². 11% of participants with known T2D were treated with diet, the others used oral glucose-lowering medication, with or without insulin; 6% was using insulin alone. Participants with known T2D had higher SAF than those with newly-detected T2D (SAF Z-score 0.56 ± 0.99 vs 0.34 ± 0.89 AU, p < 0.001), which reflects a longer duration of hyperglycaemia in the former group. Participants with existing CVD and T2D had the highest SAF Z-score: 0.78 ± 1.25 AU. During a median follow-up of 3.7 yrs., 195 (7.6%) developed an atherosclerotic CVD event, while 137 (5.4%) died. SAF was strongly associated with the combined outcome of a new CVD event or mortality (OR 2.59, 95% CI 2.10-3.20, p < 0.001), as well as incidence of CVD (OR 2.05, 95% CI 1.61-2.61, p < 0.001) and death (OR 2.98, 2.25-3.94, p < 0.001) as a single outcome. In multivariable analysis for the combined endpoint, SAF retained its significance when sex, systolic blood pressure, HbA1c, total cholesterol, eGFR, as well as antihypertensive and statin medication were included. In a similar multivariable model, SAF was independently associated with mortality as a single outcome, but not with incident CVD.

CONCLUSIONS

Measuring SAF can assist in prediction of incident cardiovascular disease and mortality in individuals with T2D. SAF showed a stronger association with future CVD events and mortality than cholesterol or blood pressure levels.

Linking Kidney and Cardiovascular Complications in Diabetes-Impact on Prognostication and Treatment: The 2019 Edwin Bierman Award Lecture

In diabetes, increasing albuminuria and decreasing glomerular filtration rate are hallmarks of chronic kidney disease in diabetes and increase the risk of atherosclerotic cardiovascular events and mortality as well as the risk for end-stage kidney disease. For two decades, standard of care has been controlling risk factors, such as glucose, blood pressure, lipids, and lifestyle factors, and specifically use of agents blocking the renin-angiotensin system. This has improved outcome, but a large unmet need has been obvious. After many failed attempts to advance the therapeutic options, the past few years have provided several new promising treatment options such as sodium-glucose cotransporter 2 inhibitors, endothelin receptor antagonists, glucagon-like peptide 1 agonists, and nonsteroidal mineralocorticoid receptor antagonists. The benefits and side effects of these agents demonstrate the link between kidney and heart; some have beneficial effects on both, whereas for other potentially renoprotective agents, development of heart failure has been a limiting factor. They work on different pathways such as hemodynamic, metabolic, inflammatory, and fibrotic targets. We propose that treatment may be personalized if biomarkers or physiological investigations assessing activity in these pathways are applied. This could potentially pave the way for precision medicine, where treatment is optimized for maximal benefit and minimal adverse outcomes. At least it may help prioritizing agents for an individual subject.

Peripheral Nerve Conduction And Sympathetic Skin Response Are Reliable Methods to Detect Diabetic Cardiac Autonomic Neuropathy

AIM

This study aimed to investigate the role of nerve conduction studies (NCS) and sympathetic skin response (SSR) in evaluating diabetic cardiac autonomic neuropathy (DCAN).

METHODS

DCAN was diagnosed using the Ewing test combined with heart rate variability analysis. NCS and SSR were assessed by electrophysiological methods. The association between NCS/SSR and DCAN was assessed via multivariate regression and receiver-operating characteristic analyses.

RESULTS

The amplitude and conduction velocity of the motor/sensory nerve were found to be significantly lower in the DCAN+ group (all P < 0.05). A lower amplitude of peroneal nerve motor fiber was found to be associated with increased odds for DCAN (OR 2.77, P < 0.05). The SSR amplitude was lower while the SSR latency was longer in the DCAN+ group than in the DCAN- group. The receiver-operating characteristic analysis revealed that the optimal cutoff points of upper/lower limb amplitude of SSR to indicate DCAN were 1.40 mV (sensitivity, 61.9%; specificity, 66.3%, P < 0.001) and 0.85 mV (sensitivity, 66.7%; specificity, 68.5%, P < 0.001), respectively. The optimal cutoff points of upper/lower limb latency to indicate DCAN were 1.40 s (sensitivity, 61.9%; specificity, 62%, P < 0.05) and 1.81 s (sensitivity, 69.0%; specificity, 52.2%, P < 0.05), respectively.

CONCLUSIONS

NCS and SSR are reliable methods to detect DCAN. Abnormality in the peroneal nerve (motor nerve) is crucial in predicting DCAN. SSR may help predict DCAN.

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

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

Value of circulating miRNA-21 in the diagnosis of subclinical diabetic cardiomyopathy

BACKGROUND

Diabetic cardiomyopathy (DCM) is a type of cardiac dysfunction that affects approximately 12% of diabetic patients, ultimately leading to heart failure or even death. However, there is currently no efficient or specific biomarker for DCM diagnosis.

METHODS

A total of 266 subjects with type II diabetes (T2DM) were enrolled in this study and were divided into the T2DM with cardiac dysfunction (DCM) group and T2DM without cardiac dysfunction (non-DCM) group. The diagnostic efficacy of miR-21 was determined and compared with that of serum hemoglobin A1c% (HbA1c%). Db/db mice and H9c2 cells stimulated with high glucose (HG)/high fatty acid (PA) were used as in vivo and in vitro models of DCM, respectively.

RESULTS

Through echocardiography and gated-myocardial perfusion imaging (gated-MPI), 49 patients were selected to be enrolled in the DCM group, with 49 matched controls in the non-DCM group. The circulating miR-21 levels were significantly decreased in the DCM group compared to the non-DCM group (P < 0.001). The diagnostic efficiency of miR-21 (area under the curve AUC = 0.899) was higher than that of other parameters, including HbA1c%. Moreover, when miR-21 was combined with the duration of diabetes, HbA1c%, and lipid profiles, the AUC was the highest (AUC = 0.939) and had the highest diagnostic efficiency. Furthermore, overexpression of miR-21 improved the impaired mitochondrial biogenesis and decreased the cardiomyocyte apoptosis induced by HG/PA, while inhibition of miR-21 exerted the opposite effects.

CONCLUSIONS

Our findings identify circulating miR-21 as a novel biomarker in the diagnosis of DCM and provide an underlying mechanism for miRNA-based therapy for the treatment of DCM.

TRIAL REGISTRATION

The study was approved by the Ethics Committee of the Third Affiliated Hospital of Soochow University and has been registered in the Chinese Clinical Trial Registry (ChiCTR1900027080).

Diabetic cardiomyopathy: How can cardiac magnetic resonance help?

Diabetes cardiomyopathy is a specific form of cardiac disease characteristic for diabetic patients. Development of echocardiography enabled diagnosis of diabetic cardiomyopathy significantly before the occurrence of heart failure. Previously was believed that left ventricular (LV) diastolic dysfunction represents the first detectable stage of diabetic cardiomyopathy. However, speckle tracking imaging and strain evaluation showed that mechanical changes occur before LV diastolic dysfunction. Nevertheless, it seems that the first detectable stage of diabetic cardiomyopathy is myocardial interstitial fibrosis, which currently could be diagnosed predominantly by cardiac magnetic resonance. T1 mapping evaluation before and after contrast injection enables assessment of extracellular volume (ECV) and provides qualitative and quantitative assessment of interstitial myocardial fibrosis in diabetic patients. Studies showed a strong correlation between ECV-parameter of interstitial fibrosis and level of glycated hemoglobin-main parameter of glucose control in diabetes. This stage of fibrosis is still not LV hypertrophy and it is reversible, which is of a great importance because of timely initiation of treatment. The necessity for early diagnose is significantly increasing due to the fact that diabetes and arterial hypertension are concomitant disorders in the large number of diabetic patients and it has been known that the risk of interstitial myocardial fibrosis is multiplied in patients with both conditions. Future follow-up investigations are essential to determine the causal relationship between interstitial fibrosis and outcome in these patients. The aim of this review was to summarize the current knowledge and clinical usefulness of CMR in diabetic patients.

G protein-coupled receptor kinase-2: A potential biomarker for early diabetic cardiomyopathy

BACKGROUND

G protein-coupled receptor kinase-2 (GRK2) has been shown as a key regulator of cardiac function, and the myocardial GRK2 levels are mirrored by the levels in peripheral blood mononuclear cells (PBMCs). In this study, we evaluated the myocardial and PBMCs GRK2 levels in early diabetic cardiomyopathy (DCM).

METHODS

C57BL/KS-db/db male diabetic mice at 12 weeks of age, as the type 2 diabetes (T2DM) animal model of early DCM were evaluated. Forty-four T2DM patients with left ventricular diastolic dysfunction (LVDD), without evidence of hypertension, coronary artery diseases, congestive heart failure, and diabetic complications and without evidence of ischemia in a maximal treadmill exercise test, were recruited as the DM + LVDD group; 30 age-matched T2DM patients without LVDD were recruited as the DM control group. Left ventricular diastolic function was evaluated by cardiac tissue Doppler. The pseudonormal pattern of ventricular filling and E'/A' < 1 were regarded as LVDD.

RESULTS

Compared to 8-week-old diabetic mice and 12-week-old control mice, GRK2-mRNA level and expression in myocardial tissues of 12-week-old diabetic mice were significantly increased, as well as the left ventricular wall thickness and systolic function. And the collagen volume fraction (CVF), collagen-3 expression, P53 expression, and cell apoptotic rate in the myocardium of 12-week-old diabetic mice elevated as well. The GRK2-mRNA level in PBMCs of DM with LVDD was significantly higher than in DM control without LVDD.

CONCLUSIONS

GRK2 expression increased in the myocardial tissue and the PBMCs at the early stage of DCM. These data support further research on the role of GRK2 as the clinical biomarker for early DCM.

Global Longitudinal Strain (GLS) in Elderly and Its Associated Factors

BACKGROUND

cardiovascular disease is very common and can be fatal in elderly patients. It is often preceded by asymptomatic or subclinical left ventricular systolic dysfunction (LVSD). Early detection of LVSD can reduce morbidity and mortality due to cardiovascular disease. One method used in the early detection of LVSD is an assessment of global longitudinal strain (GLS). This study aimed to determine the mean value of GLS and GLS-related factors.

METHODS

this cross-sectional study was conducted among elderly patients aged > 60 years in the geriatric and cardiology clinic, Internal Medicine, CMH Hospital. Data were obtained from interviews, medical records, and transthoracic echocardiography examination. The variables of age, frailty, hypertension, coronary artery disease, dyslipidemia, and diabetes mellitus were analyzed as the determinants of a decrease in GLS. Univariate analysis was conducted for each variable. Bivariate analysis was conducted using the chi-square test with a significance level of p<0.25 and confidence interval (CI) of 95%, and multivariate analysis used a logistic regression test.

RESULTS

a total of 194 patients were admitted according to the study criteria, with a mean age of 66 years. The proportion of women was 60.8%. The study revealed that the determinants with p<0.25 are frailty, hypertension, dyslipidemia, and diabetes mellitus, with multivariate analysis frailty having an OR of 2.002 (95% CI 1.042-3.925) and diabetes mellitus having an OR of 2.278 (95% CI 1.033-5.025).

CONCLUSION

the mean value of GLS among the elderly was -21.6% (minimum value -5.3% and maximum value 29.9%). The factors that influence the decrease of GLS are frailty and diabetes mellitus.

The Drug Candidate BGP-15 Delays the Onset of Diastolic Dysfunction in the Goto-Kakizaki Rat Model of Diabetic Cardiomyopathy

Background and Aims: Diabetic cardiomyopathy (DCM) is an emerging problem worldwide due to an increase in the incidence of type 2 diabetes. Animal studies have indicated that metformin and pioglitazone can prevent DCM partly by normalizing insulin resistance, and partly by other, pleiotropic mechanisms. One clinical study has evidenced the insulin-senzitizing effect of the drug candidate BGP-15, along with additional animal studies that have confirmed its beneficial effects in models of diabetes, muscular dystrophy and heart failure, with the drug affecting chaperones, contractile proteins and mitochondria. Our aim was to investigate whether the inzulin-senzitizer BGP-15 exert any additive cardiovascular effects compared to metformin or pioglitazone, using Goto-Kakizaki (GotoK) rats. Methods: Rats were divided into five groups: (I) healthy control (Wistar), (II) diseased (GotoK), and GotoK rats treated with: (III) BGP-15, (IV) metformin, and (V) pioglitazone, respectively, for 12 weeks. Metabolic parameters and insulin levels were determined at the endpoint. Doppler echocardiography was carried out to estimate diabetes-associated cardiac dysfunction. Thoracotomy was performed after the vascular status of rats was evaluated using an isolated aortic ring method. Furthermore, western blot assays were carried out to determine expression or phosphorylation levels of selected proteins that take part in myocyte relaxation. Results: BGP-15 restored diastolic parameters (e′/a′, E/e′, LAP, E and A wave) and improved Tei-index compared to untreated GotoK rats. Vascular status was unaffected by BGP-15. Expression of sarco/endoplasmic reticulum Ca²⁺-ATPase (SERCA2a) and phosphodiesterase 9A (PDE9A) were unchanged by the treatments, but the phosphorylation level of vasodilator-stimulated phosphoprotein (VASP) and phospholamban (PLB) increased in BGP-15-treated rats, in comparison to GotoK. Conclusions: Even though the BGP-15-treatment did not interfere significantly with glucose homeostasis and vascular status, it considerably enhanced diastolic function, by affecting the SERCA/phospholamban pathway in GotoK rats. Although it requires further investigation, BGP-15 may offer a new therapeutic approach in DCM.

The value of ankle-branchial index screening for cardiovascular disease in type 2 diabetes

OBJECTIVE

To investigate the relationship between ankle-branchial index (ABI) and cardiovascular disease in type 2 diabetes patients.

METHODS

A total of 634 inpatients with type 2 diabetes were recruited in this cross-sectional study. All patients were measured with ABI and computed tomography angiography (CTA) scan for coronary artery disease (CAD). According to ABI values, patients were divided into three groups: low-ABI group (ABI < 0.9, n = 259), normal-ABI group (ABI = 0.9-1.3, n = 272), and high-ABI group (ABI > 1.3, n = 103). According to the manifestation of coronary CTA, the patients were divided into CAD group (n = 348) and non-CAD group (n = 286). Their clinical data and biochemical parameters were compared and analysed.

RESULTS

The prevalence of CAD in low-ABI group (90%) was significantly higher than that of normal-ABI group (33%) and high-ABI group (25%) (both P < 0.01). Spearman correlation analysis showed that age, sex, duration, spontaneous bacterial peritonitis, total cholesterol (TC), triglyceride, low-density lipoprotein cholesterol (LDL-C), serum creatinine, and glycosylated haemoglobin (HbA_1c ) were positively correlated with CAD, and high-density lipoprotein cholesterol (HDL-C), glomerular filtration rate, and ABI were negatively correlated with CAD. Logistic regression analysis further revealed that age, sex, duration, TC, HDL-C, LDL-C, HbA_1c , and ABI were independent risk factors of CAD. After all potential confounders is adjusted, the risk of CAD in low-ABI group still increased over four times than the normal-ABI group (odds ratio [OR], 5.32; 95% CI, 1.973-16.5; P < 0.001). In female patients, this risk increased more than nine times (OR, 10.63; 95% CI, 3.416-17.8; P < 0.001). Receiver-operating characteristic analysis indicated that ABI < 1.045 predicted the occurrence of CAD (sensitivity, 79.7%; specificity, 71.5%; P < 0.01).

CONCLUSIONS

ABI is an independent risk factor for CAD and may be a potential simple screening instrument for CAD in Chinese type 2 diabetic patients, especially in elder women.

Skin autofluorescence is associated with high-sensitive cardiac troponin T, a circulating cardiac biomarker, in Japanese patients with diabetes: A cross-sectional study

The study aims to evaluate the relationship between skin autofluorescence, a marker of advanced glycated end-products accumulation in tissue, and high-sensitive cardiac troponin T, a cardiovascular biomarker, in Japanese subjects with diabetes. A total of 145 subjects with diabetes and 32 nondiabetic subjects as control attending the outpatient clinic were examined. Skin autofluorescence was measured using the AGE Reader™. Univariate and multivariate regression analyses were used to identify the factors associated with the high-sensitive cardiac troponin T and N-terminal pro-B-type natriuretic peptide values. Skin autofluorescence, high-sensitive cardiac troponin T, and maximum intima-media thickness values were significantly higher in subjects with diabetes than in nondiabetic subjects. Diabetic subjects with skin autofluorescence level⩾2.47 AU (median value) had higher levels of N-terminal pro-B-type natriuretic peptide ( p = 0.006), high-sensitive cardiac troponin T ( p < 0.0001), pentosidine ( p = 0.011) and maximum intima-media thickness ( p = 0.017) compared to those with skin autofluorescence level <2.47 AU. A multivariate regression analysis using variables that were significantly correlated with high-sensitive cardiac troponin T and N-terminal pro-B-type natriuretic peptide, revealed that estimated glomerular filtration rate (β = -0.364, p < 0.001) and skin autofluorescence (β = 0.254, p  = 0.0022) were independent determinants of high-sensitive cardiac troponin T, but the variables that were significant in the univariate analysis were no longer predictors for N-terminal pro-B-type natriuretic peptide. Skin autofluorescence measured with the AGE Reader™ could be an easy and noninvasive surrogate marker for identifying diabetic subjects at high risk for subclinical cardiac injury.

Type 2 diabetes and heart failure: Characteristics and prognosis in preserved, mid-range and reduced ventricular function

OBJECTIVE

To study the characteristics and prognostic implications of type 2 diabetes in different heart failure entities from a nationwide perspective.

METHODS

This observational study comprised 30,696 heart failure patients prospectively included in the Swedish Heart Failure Registry (SwedeHF) 2003-2011 from specialist care, with mortality information available until December 2014. Patients were categorized into three heart failure entities by their left ventricular ejection fraction (heart failure with preserved ejection fraction: ⩾50%, heart failure with mid-range ejection fraction: 40%-49% and heart failure with reduced ejection fraction: <40%). All-cause mortality stratified by type 2 diabetes and heart failure entity was studied by Cox regression.

RESULTS

Among the patients, 22% had heart failure with preserved ejection fraction, 21% had heart failure with mid-range ejection fraction and 57% had heart failure with reduced ejection fraction. The proportion of type 2 diabetes was similar, ≈25% in each heart failure entity. Patients with type 2 diabetes and heart failure with preserved ejection fraction were older, more often female and burdened with hypertension and renal impairment compared with heart failure with mid-range ejection fraction and heart failure with reduced ejection fraction patients among whom ischaemic heart disease was more common. Type 2 diabetes remained an independent mortality predictor across all heart failure entities after multivariable adjustment, somewhat stronger in heart failure with left ventricular ejection fraction below 50% (hazard ratio, 95% confidence interval; heart failure with preserved ejection fraction: 1.32 [1.22-1.43], heart failure with mid-range ejection fraction: 1.51 [1.39-1.65], heart failure with reduced ejection fraction: 1.46 [1.39-1.54]; p-value for interaction, p = 0.0049).

CONCLUSION

Type 2 diabetes is an independent mortality predictor across all heart failure entities increasing mortality risk by 30%-50%. In type 2 diabetes, the heart failure with mid-range ejection fraction entity resembles heart failure with reduced ejection fraction in clinical characteristics, risk factor pattern and prognosis.

Relation of Aortic Stiffness to Left Ventricular Remodeling in Younger Adults With Type 2 Diabetes

Individuals with type 2 diabetes have a three- to fivefold increased risk of developing heart failure. Diabetic cardiomyopathy is typified by left ventricular (LV) concentric remodeling, which is a recognized predictor of adverse cardiovascular events. Although the mechanisms underlying LV remodeling in type 2 diabetes are unclear, progressive aortic stiffening may be a key determinant. The aim of this study was to assess the relationship between aortic stiffness and LV geometry in younger adults with type 2 diabetes, using multiparametric cardiovascular MRI. We prospectively recruited 80 adults (aged 18-65 years) with type 2 diabetes and no cardiovascular disease and 20 age- and sex-matched healthy control subjects. All subjects underwent comprehensive bio-anthropometric assessment and cardiac MRI, including measurement of aortic stiffness by aortic distensibility (AD). Type 2 diabetes was associated with increased LV mass, concentric LV remodeling, and lower AD compared with control subjects. On multivariable linear regression, AD was independently associated with concentric LV remodeling in type 2 diabetes. Aortic stiffness may therefore be a potential therapeutic target to prevent the development of heart failure in type 2 diabetes.

The importance of subclinical left ventricular dysfunction and blood pressure pattern in asymptomatic type-2 diabetic patients: the diagnostic and prognostic significance of Tissue Doppler parameters, left ventricular global longitudinal strain, and nighttime blood pressure during sleep

The primary aims of this study have been to explore the diagnostic and prognostic significance of Tissue Doppler parameters (TDI), global longitudinal strain (GLS), and blood pressure (BP) pattern in normotensive diabetic patients.

METHODS

The study consisted of 121 diabetic patients and 41 healthy subjects. Conventional and TDI echocardiography were performed on all patients, including E/Em (ratio of diastolic velocities). GLS was derived from two-dimensional speckle-tracking. Ambulatory BP monitoring (ABPM) was obtained over 24h. Over the three year follow up, the end points were cardiac events (myocardial infarction, coronary revascularization procedures, new-onset angina, heart failure).

RESULTS

GLS was found to be significantly lower (-17.5±2.1vs-24.4±2.4; p<0.001), while E/Em was significantly higher (10.3±2.24vs7.4±1.8; p<0.001) in diabetic patients. A non-dipping pattern of BP was observed in 38 diabetic patients (31.4%); 14 diabetic patients had an increase in their nocturnal BP. Significant predictors of an adverse cardiac event: a reduction of GLS value (-17%,p=0.05) increase in E/Em (>15, p=0.002) and systolic BP during nocturnal sleep (>119mmHg,p=0.020).

CONCLUSION

Early detection of nocturnal hypertension and subclinical LV dysfunction by TDI and 2D spackle tracking are of significant clinical and prognostic importance.

Arterial-ventricular coupling in type 1 diabetes: arterial stiffness is associated with impaired global longitudinal strain in type 1 diabetes patients-the Thousand & 1 Study

AIMS

Diabetes is associated with higher arterial stiffness-an early marker of cardiovascular disease. The coupling between arterial stiffness and myocardial function is still unresolved. We investigate associations between arterial stiffness and early myocardial impairment assessed with advanced echocardiography.

METHODS

In 305 type 1 diabetes (T1D) patients without known heart disease and with normal left ventricular ejection fraction (LVEF) (biplane LVEF > 45%), we measured arterial stiffness as pulse wave velocity (PWV) and performed conventional and speckle-tracking echocardiography assessing global longitudinal strain (GLS) as a measure of systolic myocardial function. Associations between PWV and myocardial function were reported as standardized beta values from adjusted regression models including age, sex, mean arterial pressure, body mass index, HbA_1c, diabetes duration, estimated glomerular filtration rate, degree of albuminuria, total cholesterol, heart rate and smoking.

RESULTS

Patients were 54 (12) years [mean (SD)], 152 (50%) females, diabetes duration 31 (16) years, HbA_1c 65 (12) mmol/mol, LVEF 58 (5) %, GLS -18.2 (2.6) % and PWV 10.2 (3.4) m/s. There was no association between PWV and LVEF (p = 0.93). Conversely, there was a highly significant association between PWV and GLS in crude and multivariable models (standardized β-coefficient 0.25, p < 0.001 and 0.16, p = 0.036, respectively). Also, diastolic function measured as E/e' was highly associated with PWV in crude and multivariable models (standardized β-coefficient 0.43, p < 0.001 and 0.17, p = 0.016, respectively).

CONCLUSIONS

In T1D patients with normal LVEF and without known heart disease, higher arterial stiffness is independently associated with early systolic and diastolic myocardial impairment detectable by advanced echocardiography. Although unable to demonstrate causality, we display a relationship between diabetic angiopathy and diabetic cardiomyopathy (H-3-2009-139 and PROFIL-H-B-2009-056).

Relation of elevated serum uric acid levels to first-degree heart block and other cardiac conduction defects in hospitalized patients with type 2 diabetes

AIMS

Several studies have reported that moderately elevated serum uric acid levels are associated with an increased risk of tachyarrhythmias (mainly atrial fibrillation) in patients with and without type 2 diabetes mellitus (T2DM). It is currently unknown whether an association also exists between elevated serum uric acid levels and cardiac conduction defects in patients with T2DM.

METHODS

We retrospectively analyzed a hospital-based sample of 967 patients with T2DM discharged from our Division of Endocrinology over the years 2007-2014. Standard electrocardiograms were performed on all patients and were interpreted by expert cardiologists.

RESULTS

Overall, 267 (27.6%) patients had some type of conduction defects on electrocardiograms (defined as at least one block among first-degree atrio-ventricular block, second-degree block, third-degree block, left bundle branch block, right bundle branch block, left anterior hemi-block or left posterior hemi-block). Patients in the 3rd serum uric acid tertile had a higher prevalence of any cardiac conduction defects than those belonging to 2nd or 1st tertile, respectively (35.8% vs. 25.0% vs. 22.6%; p<0.0001). Elevated serum uric acid levels were associated with a nearly twofold increased risk of cardiac conduction defects after adjustment for age, sex, hemoglobin A1c, diabetes duration, metabolic syndrome, chronic kidney disease, chronic obstructive pulmonary disease, ischemic heart disease, valvular heart disease and medication use (adjusted-odds ratio 1.84, 95% confidence intervals 1.2-2.9; p=0.009).

CONCLUSIONS

Moderately elevated serum uric acid levels are associated with an increased prevalence of any cardiac conduction defects in hospitalized patients with T2DM, independent of multiple risk factors and potential confounding variables.

QTc prolongation in Black diabetic subjects with cardiac autonomic neuropathy

BACKGROUND

Prolonged corrected QT (QTc) has been identified as a risk factor for malignant arrhythmias and sudden cardiac death. Caucasian studies have shown a definite relationship between QTc prolongation and Cardiac Autonomic Neuropathy (CAN) in diabetic subjects.

OBJECTIVE

To determine the prevalence of prolonged QTc in Black diabetic individuals with CAN and to ascertain how prolonged QTc correlated with the severity of CAN among these patients.

METHODS

A total of 176 adult diabetic subjects were studied, 87 males and 89 females. There was a control group of non-diabetic individuals. Cardiac autonomic function was assessed using five cardiovascular autonomic function tests. CAN was diagnosed if 2 or more of these tests were abnormal. Severity of CAN was determined according to the number of abnormal tests. QTc > 0.440 was regarded as prolonged.

RESULTS

Fifty-one out of the 176 diabetic subjects (29%) had CAN. The prevalence of prolonged QTc in diabetic subjects with CAN was 12%. QTc was prolonged in 1.6% and 0.6% of diabetic individuals without CAN and controls respectively. Although QTc correlated strongly with cardiac autonomic function neuropathy, there was no definite relationship between QTc prolongation and severity of CAN.

CONCLUSION

This study in a Black population is in agreement with the well-known relationship between QTc prolongation and CAN reported in Caucasian studies. In view of the wide variability of QTc in this study population, it is suggested that relative QTc increase may be a better indicator of CAN than a definite QTc prolongation of greater than 0.440.

Predicting readmission risk of patients with diabetes hospitalized for cardiovascular disease: a retrospective cohort study

OBJECTIVE

To develop and validate a tool that predicts 30d readmission risk of patients with diabetes hospitalized for cardiovascular disease (CVD), the Diabetes Early Readmission Risk Indicator-CVD (DERRI-CVD™).

METHODS

A cohort of 8189 discharges was retrospectively selected from electronic records of adult patients with diabetes hospitalized for CVD. Discharges of 60% of the patients (n=4950) were randomly selected as a training sample and the remaining 40% (n=3219) were the validation sample.

RESULTS

Statistically significant predictors of all-cause 30d readmission risk were identified by multivariable logistic regression modeling: education level, employment status, living within 5miles of the hospital, pre-admission diabetes therapy, macrovascular complications, admission serum creatinine and albumin levels, having a hospital discharge within 90days pre-admission, and a psychiatric diagnosis. Model discrimination and calibration were good (C-statistic 0.71). Performance in the validation sample was comparable. Predicted 30d readmission risk was similar in the training and validation samples (38.6% and 35.1% in the highest quintiles).

CONCLUSIONS

The DERRI-CVD™ may be a valid tool to predict all-cause 30d readmission risk of patients with diabetes hospitalized for CVD. Identifying high-risk patients may encourage the use of interventions targeting those at greatest risk, potentially leading to better outcomes and lower healthcare costs.

The relationship between right ventricular deformation and heart rate variability in asymptomatic diabetic patients

OBJECTIVE

To investigate heart rate variability (HRV) and right ventricular (RV) remodeling in asymptomatic diabetic patients, as well as the relationship between HRV indices and RV structure, function and deformation.

METHOD

This cross-sectional study included 59 asymptomatic patients with type 2 diabetes and 45 healthy controls without cardiovascular risk factors. All study subjects underwent 24-h Holter monitoring, laboratory analyses and complete two-dimensional echocardiography examination (2DE).

RESULTS

RV diastolic function and longitudinal deformation were significantly impaired in diabetic individuals comparing with controls. RV global longitudinal strain and layer-specific longitudinal strains were significantly decreased in diabetic group. The same trend of changes in RV deformation was observed for global RV and lateral wall. All parameters of time and frequency domain of HRV were reduced in diabetic subjects. RV endocardial longitudinal strain together with LV mass index, mitral E/e' ratio and HbA1c correlated with HRV parameters. However, multivariate linear regression analysis showed that only RV endocardial longitudinal strain and LV mass index are associated with HRV parameters independently of age, BMI, HbA1c, RV free wall thickness and pulmonary artery pressure.

CONCLUSIONS

RV subendocardial strain is independently associated with HRV parameters in the whole study population. This reveals potentially important role of determination of layer-specific RV longitudinal function as important marker of preclinical cardiac damage, but also indirectly show the impairment of cardiac autonomic function in diabetic patients.

Is Diabetes Mellitus a Risk Factor for Poor Outcomes after Left Ventricular Assist Device Placement?

Diabetes mellitus is associated with adverse outcomes in patients with cardiovascular diseases, including heart failure. Left ventricular assist devices (LVADs) are increasingly used as life-saving therapy for advanced heart failure. The effects of pre-LVAD diabetes on long-term outcomes after LVAD implantation are not well understood. In this study, we retrospectively evaluated the effect of existing diabetes on post-LVAD outcomes. Data on 288 LVAD recipients from 2006 through 2013 were reviewed. Patients were stratified in accordance with their histories of diabetes. Baseline demographic, laboratory, hemodynamic, and echocardiographic information before LVAD placement were reviewed, together with the post-LVAD incidence of major adverse outcomes. Kaplan-Meier analysis and Cox regression analysis were performed. Our cohort comprised 122 patients with diabetes and 166 patients without. The mean glycosylated hemoglobin A_1c level in the diabetes group was 7.4% ± 1.6%. Diabetic patients at baseline had a more adverse medical profile than did nondiabetic patients. There were no differences in major outcomes between the 2 groups other than a higher incidence of hemolysis in the diabetes group: 12 (10%) vs 5 (3%); P=0.02. There was no difference in survival outcomes between the groups. Diabetic patients did not have worse survival or more adverse outcomes than did nondiabetic patients in this study, perhaps because of improved diabetes control, or improvement in biochemical derangements after normalization of cardiac output with LVAD therapy. A diagnosis of diabetes was an independent predictor of hemolysis. Further studies to evaluate the link between hemolysis and diabetes are indicated.

A large frontal QRS-T angle is a strong predictor of the long-term risk of myocardial infarction and all-cause mortality in the diabetic population

BACKGROUND

A large angle between the QRS vector and the T-wave vector (QRS-T angle) in electrocardiograms (ECGs) has recently been introduced as a marker of poor prognosis. The prognostic value in diabetes is unknown. We assessed the long-term predictive power of the frontal plane QRS-T angle in the diabetic population.

METHODS

In 1992-93, the diabetic population of the municipality of Horsens, Denmark, was delineated by the prescription method, and an age- and gender-stratified sample of 240 diabetic persons was randomly selected. In 2015, 12-lead ECGs taken in 1993-94 were analyzed. Vital statistics were obtained from the Danish Civil Registration System and data regarding hospitalizations taken from The National Patient Registry in July 2015.

RESULTS

In total, 178 people agreed to participate (74%) in the study, with the mean (sd) age being 58.9 (10.2) years and 56% being male. The total observation time was 21.5 (0.18) years, during which time 122 (69%) persons died, 32 (18%) suffered a myocardial infarction (MI) and 126 (71%) reached the composite endpoint of non-fatal MI or all-cause death. In Cox regression multivariate analysis a QRS-T angle above 90° was found to be an independent predictor of all-cause death (HR=2.2 (95% CI: 1.3-3.8)), MI (HR=2.95 (95% CI: 1.1-7.7)) and MI or all-cause death (HR=2.0 (95% CI: 1.2-3.5)) (all p<0.05), when adjusting for the effects of co-variates (gender, age, length of diabetes, BMI, total cholesterol, diabetes type, hemoglobin A1c, smoking, hypertension and previous MI).

CONCLUSION

A large QRS-T angle is a strong, independent long-term predictor of all-cause mortality, MI and MI or all-cause death in the diabetic population.

Association between serum 25(OH)D3 and cardiovascular morbidity and mortality in people with Type 2 diabetes: a community-based cohort study

AIM

We aimed to explore the association between vitamin D and cardiovascular morbidity and mortality in people with Type 2 diabetes recruited from a community-based study because there is limited and inconsistent research of this group.

METHODS

A prospective community-based cohort study among people aged 55-66 years with Type 2 diabetes as part of The Cardiovascular Risk in Type 2 Diabetes - A Prospective Study in Primary Care (CARDIPP). We analysed serum 25-hydroxyvitamin D₃ [25(OH)D₃ ] at baseline. Cox regression analyses were used to calculate hazard ratios (HR) for the first myocardial infarction, stroke or cardiovascular mortality according to 25(OH)D₃ .

RESULTS

We examined 698 people with a mean follow-up of 7.3 years. Serum 25(OH)D₃ was inversely associated with the risk of cardiovascular morbidity and mortality: HR 0.98 [95% confidence interval (CI) 0.96 to 0.99, P = 0.001]. Compared with the fourth quartile (Q4) [25(OH)D₃ > 61.8 nmol/l], HR (with 95% CI) was 3.46 (1.60 to 7.47) in Q1 [25(OH)D₃ < 35.5 nmol/l] (P = 0.002); 2.26 (1.01 to 5.06) in Q2 [25(OH)D₃ 35.5-47.5 nmol/l] (P = 0.047); and 1.62 (0.70 to 3.76) in Q3 [25(OH)D₃ 47.5-61.8 nmol/l] (P = 0.26) when adjusting for age, sex and season. The results remained significant after adjusting also for cardiovascular risk factors, physiological variables including parathyroid hormone and previous cardiovascular disease (P = 0.027).

CONCLUSIONS

Low 25(OH)D₃ is associated with an increased risk of cardiovascular morbidity and mortality in people with Type 2 diabetes independent of parathyroid hormone. Vitamin D could be considered as a prognostic factor. Future studies are needed to explore whether vitamin D deficiency is a modifiable risk factor in Type 2 diabetes.

Cardiovascular Screening for the Asymptomatic Patient with Diabetes: More Cons Than Pros

Diabetes mellitus is associated with an increased risk of coronary heart disease (CHD) morbidity and mortality. Although it frequently coexists with other cardiovascular disease (CVD) risk factors, it confers an increased risk for CVD events on its own. Coronary atherosclerosis is generally more aggressive and widespread in people with diabetes (PWD) and is frequently asymptomatic. Screening for silent myocardial ischaemia can be applied in a wide variety of ways. In nearly all asymptomatic PWD, however, the results of screening will generally not change medical therapy, since aggressive preventive measures, such as control of blood pressure and lipids, would have been already indicated, and above all, invasive revascularization procedures (either with percutaneous coronary intervention or coronary artery bypass grafting) have not been shown in randomized clinical trials to confer any benefit on morbidity and mortality. Still, unresolved issues remain regarding the extent of the underlying ischaemia that might affect the risk and the benefit of revascularization (on top of optimal medical therapy) in ameliorating this risk in patients with moderate to severe ischaemia. The issues related to the detection of coronary atherosclerosis and ischaemia, as well as the studies related to management of CHD in asymptomatic PWD, will be reviewed here.

Causes of death in childhood-onset Type 1 diabetes: long-term follow-up

AIMS

To assess the causes of death and cause-specific standardized mortality ratios in two nationwide, population-based cohorts diagnosed with Type 1 diabetes during the periods 1973-1982 and 1989-2012, and to evaluate changes in causes of death during the follow-up period.

METHODS

People with Type 1 diabetes who were aged < 15 years at diagnosis were identified in the Norwegian Childhood Diabetes Registry and followed from diagnosis until death, emigration or September 2013 (n = 7871). We assessed causes of death by linking data to the nationwide Cause of Death Registry and through a review committee that evaluated medical records, autopsy reports and death certificates.

RESULTS

During a mean (range) follow-up of 16.8 (0-40.7) years, 241 individuals (3.1%) died, representing 132 143 person-years. The leading cause of death before the age of 30 years was acute complications (41/119, 34.5%). After the age of 30 years cardiovascular disease was predominant (41/122, 33.6%), although death attributable to acute complications was still important in this age group (22/122, 18.0%). A total of 5% of deaths were caused by 'dead-in-bed' syndrome. The standardized mortality ratio was elevated for cardiovascular disease [11.9 (95% CI 8.6-16.4)] and violent death [1.7 (95% CI 1.3-2.1)] in both sexes combined, but was elevated for suicide only in women [2.5 (95% CI 1.2-5.3)]. The risk of death from acute complications was approximately half in women compared with men [hazard ratio 0.43 (95% CI 0.25-0.76)], and did not change with more recent year of diagnosis [hazard ratio 1.02 (0.98-1.05)].

CONCLUSIONS

There was no change in mortality attributable to acute complications during the study period. To reduce premature mortality in people with childhood-onset diabetes focus should be on prevention of acute complications. Male gender implied increased risk.

Diabetic Cardiomyopathy: Current Approach and Potential Diagnostic and Therapeutic Targets

Although ischemic heart disease is the major cause of death in diabetic patients, diabetic cardiomyopathy (DCM) is increasingly recognized as a clinically relevant entity. Considering that it comprises a variety of mechanisms and effects on cardiac function, increasing the risk of heart failure and worsening the prognosis of this patient category, DCM represents an important complication of diabetes mellitus, with a silent development in its earlier stages, involving intricate pathophysiological mechanisms, including oxidative stress, defective calcium handling, altered mitochondrial function, remodeling of the extracellular matrix, and consequent deficient cardiomyocyte contractility. While DCM is common in diabetic asymptomatic patients, it is frequently underdiagnosed, due to few diagnostic possibilities in its early stages. Moreover, since a strategy for prevention and treatment in order to improve the prognosis of DCM has not been established, it is important to identify clear pathophysiological landmarks, to pinpoint the available diagnostic possibilities and to spot potential therapeutic targets.

Silent diabetic cardiomyopathy in everyday practice: a clinical and echocardiographic study

BACKGROUND

Whether type 2 diabetes mellitus (DM) in the absence of hypertension (HTA) and coronary artery disease (CAD) affects left ventricular (LV) phenotype and function among asymptomatic DM patients that can be easily discovered in everyday practice, what is the clinical risk profile for diabetic cardiomyopathy and how HTA and CAD modulate LV structure and function above diabetic cardiomyopathy, are still incompletely answered questions.

METHODS

In 210 DM patients (group I: 70 asymptomatic DM patients without HTA and CAD; group II: 70 DM patients with HTA and no CAD; group III: 70 DM patients with CAD and no HTA) and 80 healthy individuals, comprehensive echocardiography including speckle tracking strain and strain rate analysis, was done.

RESULTS

Compared to control DM patients without HTA and CAD had increased LV mass, more frequently concentric remodeling, impaired LV relaxation and lower LV ejection fraction (EF), fraction of shortening (FS) and mitral annular plane excursion (MAPSE). Addition of HTA further impaired EF, FS and MAPSE and aggravated diastolic dysfunction, whereas concomitant CAD further impaired FS and MAPSE. Peak global longitudinal strain (Slong) and early diastolic longitudinal strain rate (SRlong E) were impaired in group I compared to control, even when EF was preserved. Peak circumferential strain (Scirc) was impaired only when DM was associated with HTA or CAD. In multivariate analysis DM was significantly and independently from HTA, CAD, age, gender and body mass index associated with: increased LV mass, concentric LV remodeling, lower EF, FS, MAPSE, Slong, SRlongE and distorted diastolic parameters. DM duration, glycosylated hemoglobin, microalbuminuria and retinopathy, were not independent predictors of LV geometry and function.

CONCLUSION

DM per se has strong and independent influence on LV phenotype and function that can be detected by conventional and speckle tracking echocardiography in everyday clinical practice, even in asymptomatic patients. We could not confirm that these changes were independently related to duration of DM, quality of metabolic control and presence of microvascular complications. Concomitant HTA or CAD furthermore distorted LV systolic and diastolic function.

Improved diastolic function in type 2 diabetes after a six month liraglutide treatment

AIMS

To investigate whether liraglutide improves diastolic function in type 2 diabetes.

METHODS

Thirty-seven patients with type 2 diabetes who began liraglutide therapy between June 2013 and May 2014 were enrolled in this observational, prospective study. 26 patients received liraglutide therapy for at least 6months. The remaining 11 patients withdrew from liraglutide therapy during the first month, were started on other hypoglycaemic therapies and formed the control group. Anthropometric, metabolic and echocardiographic parameters including pulsed wave tissue Doppler imaging were evaluated at baseline and at 6months.

RESULTS

In the liraglutide group the early diastolic mitral annulus velocity on the lateral (e-lat) and medial (e-med) sides of the mitral annulus increased from 9.2±3.4 to 11.6±4.7cm/s (p<0.001) and from 6.9±1.7 to 8.4±2.6cm/s (p<0.003), respectively. The ratio of early-to-late velocities on the lateral and medial sides of the mitral annulus increased from 0.7±0.3 to 0.9±0.4 (p<0.001) and from 0.5±0.1 to 0.6±0.1 (p<0.02), respectively. The ratio of early diastolic mitral inflow velocity to early diastolic myocardial relaxation velocity decreased from 10.7±4.3 to 8.5±2.5 (p<0.005). No improvements in diastolic function was detected in the control group. Glucose control improved similarly in both groups: HA1bc -1.5% (-17mmol/mol) vs -1.3% (-14mmol/mol), p=0.67.

CONCLUSIONS

In patients with type 2 diabetes, 6months liraglutide treatment was associated with a significant improvement in diastolic function.

Impact of Improved Glycemic Control on Cardiac Function in Type 2 Diabetes Mellitus

BACKGROUND

Patients with type 2 diabetes mellitus are at risk of heart failure. Specific therapeutic interventions for diabetic heart disease are still elusive. We aimed to examine the impact of improved glycemic control on left ventricular (LV) function in these patients.

METHODS AND RESULTS

A total of 105 subjects with type 2 diabetes mellitus (aged 54±10 years) and poor glycemic control received optimization of treatment for blood glucose, blood pressure, and cholesterol to recommended targets for 12 months. LV systolic and diastolic function, measured by LV global longitudinal strain (GLS) and septal e' velocities, were compared before and after optimization. At baseline, patients had impaired LV systolic (GLS -14.9±3.2%) and diastolic function (e' 6.2±1.7 cm/s). After 12 months, glycated hemoglobin (HbA1c) decreased from 10.3±2.4% to 8.3±2.0%, which was associated with significant relative improvement in GLS of 21% and septal e' of 24%. There was a progressively greater improvement in GLS as patients achieved a lower final HbA1c. Patients achieving an HbA1c of <7.0% had the largest improvement. The 15 patients whose HbA1c worsened experienced a decline in GLS. Patients who improved their HbA1c by ≥1.0% had a significantly higher relative improvement in e' than those who did not (32% versus 8%; P=0.003). Baseline GLS, decrease in body mass index, and treatment with metformin were additional independent predictors of GLS improvement.

CONCLUSIONS

Improvements in glycemic control over a 12-month period led to improvements in LV systolic and diastolic function. This may have long-term prognostic implications.

Self-reported dyspnea is associated with impaired global longitudinal strain in ambulatory type 1 diabetes patients with normal ejection fraction and without known heart disease - The Thousand & 1 Study

AIMS

Identification of early signs and symptoms of heart disease is important in type 1 diabetes (T1DM). Global longitudinal strain (GLS) by speckle-tracking echocardiography can detect subtle impairments in myocardial function. We investigated the association between myocardial function and degree of dyspnea in patients with normal left ventricular ejection fraction (LVEF) and without known heart disease.

METHODS

Ambulatory patients from Steno Diabetes Center. Conventional echocardiography and GLS was performed. Patients reported degree of dyspnea according to the NYHA classification. Patients with LVEF≤45% were excluded. Data were analyzed in uni-and multivariable models.

RESULTS

A total of 1075 T1DM patients were included. Mean age 49.5years, 52% men, mean diabetes duration 25.8years; 835 (77.7%) reported no dyspnea, 156 (14.5%) NYHA I, 68 (6.3%) NYHA II, and 16 (1.5%) NYHA III-IV. LVEF did not differ between groups of dyspnea in neither univariable nor multivariable models (p>0.1). E/e' was associated with degree of dyspnea in both univariable (p<0.001) and multivariable models (p=0.048). GLS was associated with degree of dyspnea in a dose-response relationship in both univariable (p<0.001) and multivariable models (p<0.001).

CONCLUSIONS

Degree of dyspnea is independently associated with impaired myocardial function by GLS in T1DM patients with normal LVEF and without known heart disease.

Anti-apolipoprotein A-1 autoantibodies as risk biomarker for cardiovascular diseases in type 2 diabetes mellitus

OBJECTIVE

Anti-Apolipoprotein A-1 autoantibodies (anti-ApoA-1 IgG) represent an emerging prognostic cardiovascular marker in patients with myocardial infarction or autoimmune diseases associated with high thrombotic events. The aim of this work is to investigate the incidence of anti-apoA-1 autoantibodies in type 2 diabetes (T2DM) patients with and without CVD and to study potential association with disease risk and its effect on plasma lipid parameters.

METHODS

Qualitative determination of anti-apoA-1 IgG was assayed in sera from 302 subjects classified into T2DM patients (n=102), T2DM+CVD (n=112) and healthy controls (n=88).

RESULTS

The incidence of anti-apoA-1 IgG was significantly higher among CVD patients (35.7%) than T2DM patients (8.8%) or control subjects (6.1%), p<0.0001. A significant association with CVD was identified (p<0.0001) and subjects who were positive for anti-apoA-1 IgG were at 8.5 times increased risk to develop CVD when compared to controls. Diabetic patients who were positive for the antibodies showed 5.7 times increased CVD risk. ROC analysis indicated anti-apoA-1 IgG as a risk biomarker for CVD in T2DM patients with an AUC value of 0.76, sensitivity of 35.7% and specificity of 91.2%. Studying the effect on lipid parameters, anti-apoA-1 IgG associated with significantly higher serum concentrations of TC and non-HDL-C in all groups and with higher concentrations of LDL-C in diabetic patients and higher TC/HDL-C ratio in CVD patients.

CONCLUSION

Our results indicate that anti-apoA-1 IgG is a cardiovascular risk biomarker in T2DM patients.

Improvement of cardiac dysfunction by bilateral surgical renal denervation in animals with diabetes induced by high fructose and high fat diet

AIMS

Insulin resistance (IR) and sympathetic over-activation play a critical role in diabetic cardiomyopathy (DCM). Percutaneous renal sympathetic denervation (RDN) was tested to treat refractory hypertension. However, the benefits of RDN for DCM and IR still remain unknown. The present study aimed to investigate the effect and associated mechanisms of bilateral surgical RDN (bsRDN) on cardiac function and glucose metabolism in animals with diabetes.

METHODS

Thirty-two male New Zealand white rabbits were randomly assigned to Chow (n=8, normal diet) and TEST (n=24, high-fructose fat diet [HFD]) groups. At 48 weeks after HFD feeding, animals in the TEST group were randomized to the Sham, HFD, and RDN subgroups and were fed a HFD for an additional 8 weeks. Repeated measurements of cardiac function, IR, apoptosis/autophagy, and histopathological assessment were performed at 48 and 56 weeks.

RESULTS

HFD feeding for 56 weeks induced IR and diastolic cardiac dysfunction with hypertrophy in septum but well preserved eject fraction in the animals. Impaired IR further deteriorated over the time in the RDN group, featured by a more profound reduction in GLUT4 mRNA and its translocation to the plasma membrane. Successful denervation was associated with improvement of cardiac function via preventing myocardial fibrosis and over-expression of procollagen III, mammalian target of rapamycin, and cardiac apoptosis. Cardiac autophagy, assessed by either electron microscopy or Western blot, was enhanced by bsRDN.

CONCLUSIONS

Renal sympathetic denervation led to a significant improvement of HFD-induced cardiac dysfunction by shifting the cardiac apoptosis to autophagy, but worsening IR. Further study is required to identify the clinical benefits of RDN.

Prognostic significance of glycemic variability after cardiac surgery

INTRODUCTION

The prognostic significance of acute glycemic variability (GV) after cardiac surgery is not known. This study was therefore planned to analyze the independent prognostic value of GV after cardiac surgery.

MATERIALS AND METHODS

This is a single center prospective observational study in 870 consecutive cardiac surgery patients over a 3-month period at a tertiary care institute in India.

RESULTS

In linear regression analysis, GV was a significant predictor of length of stay in intensive care unit (LOS-ICU) (beta 0.102, p=0.007) and rise in creatinine after surgery (beta 0.229, p<0.001). Mean POC-BG was a significant positive predictor of length of stay in hospital (LOS-hospital) (beta 0.1, p=0.004). In multivariable logistic regression analysis, GV predicted prolonged LOS-ICU (p=0.006, OR 1.016) and acute kidney injury (p<0.001, OR 1.034).

CONCLUSION

This study showed that GV, as measured by standard deviation, was a predictor of LOS-ICU, rise in creatinine and AKI after cardiac surgery. GV is therefore a new dimension in postoperative glycemic management in cardiac surgery patients, which needs to be explored.

Early changes in longitudinal deformation indices in young asymptomatic patients with type 1 diabetes mellitus: assessment by speckle-tracking echocardiography

BACKGROUND

We explored early changes in regional left ventricular systolic and diastolic function assessed by speckle-tracking echocardiography (STE) in young asymptomatic patients with type 1 diabetes mellitus (DM), compared with healthy controls.

METHODS

We enrolled 30 normotensive asymptomatic patients with type 1 DM, age ≤40 years, DM duration >5 years, and left ventricular ejection fraction ≥50%; and thirty matched controls. They underwent conventional echocardiography, and tissue Doppler imaging (TDI). Myocardial deformation indices were measured by STE. We measured global longitudinal systolic strain, global longitudinal systolic strain rate, and global longitudinal early diastolic strain rate, as an average of 18 myocardial segments.

RESULTS

The mean age was 27.7±4.5 years, (41.7% males). The mean duration of diabetes was 14.3±5.8 years. The 2-D ejection fraction was lower in diabetic patients versus controls (P=0.03). The trans-mitral A peak was higher, and isovolumetric relaxation time longer in diabetics (P<0.05 for both). Both lateral and septal É values were lower, and E/É ratio higher in diabetics (P<0.05 for all). The global longitudinal systolic strain and strain rate were decreased in diabetics (-17.7±2.5% versus -21.2±1.7%, and -1.1±0.2 versus -1.3±0.2 s-1, P<0.001 and P=0.003, respectively). The global longitudinal early diastolic strain rate was comparable to controls (1.5±0.4 versus 1.6±0.3 s-1, respectively, P=0.33).

CONCLUSIONS

In asymptomatic patients with type 1 DM, global longitudinal systolic function measured by STE was impaired versus controls; diastolic function was impaired by conventional echocardiography and TDI.

Efficacy of CD34+ Stem Cell Therapy in Nonischemic Dilated Cardiomyopathy Is Absent in Patients With Diabetes but Preserved in Patients With Insulin Resistance

We evaluated the association of diabetes and insulin resistance with the response to cell therapy in patients with nonischemic dilated cardiomyopathy (DCM). A total of 45 outpatients with DCM received granulocyte colony-stimulating factor for 5 days. CD34(+) cells were then collected by apheresis and injected transendocardially. Twelve patients had diabetes mellitus (DM group), 17 had insulin resistance (IR group), and 16 displayed normal glucose metabolism (no-IR group). After stimulation, we found higher numbers of CD34(+) cells in the IR group (94 ± 73 × 10(6) cells per liter) than in the no-IR group (54 ± 35 × 10(6) cells per liter) or DM group (31 ± 20 × 10(6) cells per liter; p = .005). Similarly, apheresis yielded the highest numbers of CD34(+) cells in the IR group (IR group, 216 ± 110 × 10(6) cells; no-IR group, 127 ± 82 × 10(6) cells; DM group, 77 ± 83 × 10(6) cells; p = .002). Six months after cell therapy, we found an increase in left ventricular ejection fraction in the IR group (+5.6% ± 6.9%) and the no-IR group (+4.4% ± 7.2%) but not in the DM group (-0.9% ± 5.4%; p = .035). The N-terminal pro-brain natriuretic peptide levels decreased in the IR and no-IR groups, but not in the DM group (-606 ± 850 pg/ml; -698 ± 1,105 pg/ml; and +238 ± 963 pg/ml, respectively; p = .034). Transendocardial CD34(+) cell therapy appears to be ineffective in DCM patients with diabetes. IR was associated with improved CD34(+) stem cell mobilization and a preserved clinical response to cell therapy.

SIGNIFICANCE

The present study is the first clinical study directly evaluating the effects of altered glucose metabolism on the efficacy of CD34(+) stem cell therapy in patients with nonischemic dilated cardiomyopathy. The results offer critical insights into the physiology of stem cell mobilization in heart failure and possibly an explanation for the often conflicting results obtained with stem cell therapy for heart failure. These results demonstrate that patients with dilated cardiomyopathy and diabetes do not benefit from autologous CD34(+) cell therapy. This finding could serve as a useful tool when selecting heart failure patients for future clinical studies in the field of stem cell therapy.

Subclinical Detection of Diabetic Cardiomyopathy with MicroRNAs: Challenges and Perspectives

The prevalence of cardiac diabetic diseases has been increased around the world, being the most common cause of death and disability among diabetic patients. In particular, diabetic cardiomyopathy is characterized with a diastolic dysfunction and cardiac remodelling without signs of hypertension and coronary artery diseases. In an early stage, it is an asymptomatic disease; however, clinical studies demonstrate that diabetic myocardia are more vulnerable to injury derived by acute myocardial infarct and are the worst prognosis for rehabilitation. Currently, biochemical and imaging diagnostic methods are unable to detect subclinical manifestation of the disease (prior to diastolic dysfunction). In this review, we elaborately discuss the current scientific evidences to propose circulating microRNAs as promising biomarkers for early detection of diabetic cardiomyopathy and, then, to identify patients at high risk of diabetic cardiomyopathy development. Moreover, here we summarise the research strategies to identify miRNAs as potential biomarkers, present limitations, challenges, and future perspectives.

Early detection of cardiac dysfunction in the type 1 diabetic heart using speckle-tracking based strain imaging

Enhanced sensitivity in echocardiographic analyses may allow for early detection of changes in cardiac function beyond the detection limits of conventional echocardiographic analyses, particularly in a small animal model. The goal of this study was to compare conventional echocardiographic measurements and speckle-tracking based strain imaging analyses in a small animal model of type 1 diabetes mellitus. Conventional analyses revealed differences in ejection fraction, fractional shortening, cardiac output, and stroke volume in diabetic animals relative to controls at 6-weeks post-diabetic onset. In contrast, when assessing short- and long-axis speckle-tracking based strain analyses, diabetic mice showed changes in average systolic radial strain, radial strain rate, radial displacement, and radial velocity, as well as decreased circumferential and longitudinal strain rate, as early as 1-week post-diabetic onset and persisting throughout the diabetic study. Further, we performed regional analyses for the LV and found that the free wall region was affected in both the short- and long-axis when assessing radial dimension parameters. These changes began 1-week post-diabetic onset and remained throughout the progression of the disease. These findings demonstrate the use of speckle-tracking based strain as an approach to elucidate cardiac dysfunction from a global perspective, identifying left ventricular cardiac regions affected during the progression of type 1 diabetes mellitus earlier than contractile changes detected by conventional echocardiographic measurements.

Type 2 diabetes and cardiac autonomic neuropathy screening using dynamic pupillometry

AIM

To determine if changes in pupillary response are useful as a screening tool for diabetes and to assess whether pupillometry is associated with cardiac autonomic neuropathy.

METHODS

We conducted a cross-sectional study with participants drawn from two settings: a hospital and a community site. At the community site, individuals with newly diagnosed diabetes as well as a random sample of control individuals without diabetes, confirmed by oral glucose tolerance test, were selected. Participants underwent an LED light stimulus test and eight pupillometry variables were measured. Outcomes were diabetes, defined by oral glucose tolerance test, and cardiac autonomic dysfunction, determined by a positive readout on two of four diagnostic tests: heart rate response to the Valsalva manoeuvre; orthostatic hypotension; 30:15 ratio; and expiration-to-inspiration ratio. The area under the curve, best threshold, sensitivity and specificity of each pupillometry variable was calculated.

RESULTS

Data from 384 people, 213 with diabetes, were analysed. The mean (±sd) age of the people with diabetes was 58.6 (±8.2) years and in the control subjects it was 56.1 (±8.6) years. When comparing individuals with and without diabetes, the amplitude of the pupil reaction had the highest area under the curve [0.69 (sensitivity: 78%; specificity: 55%)]. Cardiac autonomic neuropathy was present in 51 of the 138 people evaluated (37.0%; 95% CI 28.8-45.1). To diagnose cardiac autonomic neuropathy, two pupillometry variables had the highest area under the curve: baseline pupil radius [area under the curve: 0.71 (sensitivity: 51%; specificity: 84%)], and amplitude of the pupil reaction [area under the curve: 0.70 (sensitivity: 82%; specificity: 55%)].

CONCLUSIONS

Pupillometry is an inexpensive technique to screen for diabetes and cardiac autonomic neuropathy, but it does not have sufficient accuracy for clinical use as a screening tool.

Clinical usefulness of baroreflex sensitivity test in the detection of cardiovascular autonomic neuropathy in patients with type 2 diabetes mellitus

Cardiovascular autonomic neuropathy (CAN) is one of the most common chronic complications of diabetes. It is defined as an impaired control of the cardiovascular system by the autonomic nervous system. The gold standard in detecting it is the Ewing test suite. The usefulness of other methods is still a subject of research.

AIM

The aim of this study was to assess the clinical usefulness of baroreflex sensitivity (BRS) test in the detection of CAN in patients with type 2 diabetes mellitus.

MATERIALS AND METHODS

The study included diabetic patients: 24 with CAN, diagnosed through the Ewing tests (the mean age 58 ± 7 years, BMI 33.6 ± 5 kg*m⁻², HbA1c% 8.3 ± 3, duration of diabetes 13.3 ± 7 years), and 24 without CAN (56 ± 8 years, BMI 32.2 ± 5 kg*m-2, HbA1c% 9.1 ± 2, 9.3 ± 9 years, respectively). The control group consisted of 12 patients without diabetes, homogeneous regarding gender and age. BRS was assessed in the supine (L-BRS), and in the standing position (S-BRS).

RESULTS

L-BRS was lower in the group with CAN vs the non-CAN group (6.2 ± 4 vs 9.6 ± 4 ms/mmHg; p=0,009); S-BRS respectively (4.4 ± 3 vs 6.9 ± 4 ms/mmHg; p=0.02). BRS well differentiates patients with and without polyneuropathy. The highest sensitivity of L-BRS and SBRS for detecting CAN is by cutoff ≤ 7 ms/mmHg.

CONCLUSIONS

The study confirms the value of baroreflex sensitivity in the early detection of CAN among patients with type 2 diabetes. We recommended cutoff points for BRS to detect CAN among patients with type 2 diabetes mellitus.

The Process of Care-seeking for Myocardial Infarction Among Patients With Diabetes

BACKGROUND

People with diabetes have a higher risk for myocardial infarction (MI) than do people without diabetes. It is extremely important that patients with MI seek medical care as soon as possible after symptom onset because the shorter the time from symptom onset to treatment, the better the prognosis.

OBJECTIVE

The aim of this study was to explore how people with diabetes experience the onset of MI and how they decide to seek care.

METHODS

We interviewed 15 patients with diabetes, 7 men and 8 women, seeking care for MI. They were interviewed 1 to 5 days after their admission to hospital. Five of the participants had had a previous MI; 5 were being treated with insulin; 5, with a combination of insulin and oral antidiabetic agents; and 5, with oral agents only. Data were analyzed according to grounded theory.

RESULTS

The core category that emerged, "becoming ready to act," incorporated the related categories of perceiving symptoms, becoming aware of illness, feeling endangered, and acting on illness experience. Our results suggest that responses in each of the categories affect the care-seeking process and could be barriers or facilitators in timely care-seeking. Many participants did not see themselves as susceptible to MI and MI was not expressed as a complication of diabetes.

CONCLUSIONS

Patients with diabetes engaged in a complex care-seeking process, including several delaying barriers, when they experienced symptoms of an MI. Education for patients with diabetes should include discussions about their increased risk of MI, the range of individual variation in symptoms and onset of MI, and the best course of action when possible symptoms of MI occur.

Impact of diabetes and diastolic dysfunction on exercise capacity in normotensive patients without coronary artery disease

OBJECTIVE

The aim of this study was to determine the impact of diabetes and diastolic dysfunction on exercise capacity in asymptomatic, normotensive patients with type 2 diabetes without coronary artery disease.

METHODS

A total of 43 type 2 diabetes patients (age: 50 ± 5 years) and 20 healthy controls (age: 48 ± 4 years) were enrolled. Diastolic function was investigated by conventional pulsed-wave (PW) Doppler and tissue Doppler imaging (TDI). Exercise capacity was evaluated with cardiopulmonary exercise testing (CPET).

RESULTS

In patients with type 2 diabetes, increase in resting heart rate (HR-rest) (p = 0.013), decrease in maximum heart rate during exercise (HR-max) (p < 0.001) and exercise time (p < 0.001) compared with controls were significant. Patients had significantly increased minute ventilation volume (VE)/maximum carbon dioxide discharge (VCO2) ratio (p < 0.001), decreased maximum oxygen consumption (VO2-max) (p < 0.001), oxygen consumption at anaerobic threshold (VO2-an) (p < 0.001) and maximum carbon dioxide discharge (VCO2) (p < 0.001) compared to controls indicating significantly reduced exercise capacity. HbA1c was inversely correlated with VO2-max (r = -0.456, p < 0.01) independent of the absence or presence of mild diastolic dysfunction.

CONCLUSION

Exercise capacity was found to be significantly decreased in normotensive patients with type 2 diabetes without coronary artery disease, and this decrease was independent of diastolic dysfunction.