The effect of diabetes mellitus on prognosis and serial left ventricular function after acute myocardial infarction: contribution of both coronary disease and diastolic left ventricular dysfunction to the adverse prognosis. The MILIS Study Group

Repair of the Infarcted Heart: Cellular Effectors, Molecular Mechanisms and Therapeutic Opportunities

The adult mammalian heart has limited endogenous regenerative capacity and heals through the activation of inflammatory and fibrogenic cascades that ultimately result in the formation of a scar. After infarction, massive cardiomyocyte death releases a broad range of damage-associated molecular patterns that initiate both myocardial and systemic inflammatory responses. TLRs (toll-like receptors) and NLRs (NOD-like receptors) recognize damage-associated molecular patterns (DAMPs) and transduce downstream proinflammatory signals, leading to upregulation of cytokines (such as interleukin-1, TNF-α [tumor necrosis factor-α], and interleukin-6) and chemokines (such as CCL2 [CC chemokine ligand 2]) and recruitment of neutrophils, monocytes, and lymphocytes. Expansion and diversification of cardiac macrophages in the infarcted heart play a major role in the clearance of the infarct from dead cells and the subsequent stimulation of reparative pathways. Efferocytosis triggers the induction and release of anti-inflammatory mediators that restrain the inflammatory reaction and set the stage for the activation of reparative fibroblasts and vascular cells. Growth factor-mediated pathways, neurohumoral cascades, and matricellular proteins deposited in the provisional matrix stimulate fibroblast activation and proliferation and myofibroblast conversion. Deposition of a well-organized collagen-based extracellular matrix network protects the heart from catastrophic rupture and attenuates ventricular dilation. Scar maturation requires stimulation of endogenous signals that inhibit fibroblast activity and prevent excessive fibrosis. Moreover, in the mature scar, infarct neovessels acquire a mural cell coat that contributes to the stabilization of the microvascular network. Excessive, prolonged, or dysregulated inflammatory or fibrogenic cascades accentuate adverse remodeling and dysfunction. Moreover, inflammatory leukocytes and fibroblasts can contribute to arrhythmogenesis. Inflammatory and fibrogenic pathways may be promising therapeutic targets to attenuate heart failure progression and inhibit arrhythmia generation in patients surviving myocardial infarction.

Impact of Sex and Diabetes in Patients with Heart Failure

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

Risk Assessment of Pre-dialysis Chronic Kidney Disease (CKD) Patients for Cardiovascular Disease (CVD) in a Tertiary Hospital in Nigeria: A Case-Controlled Cross-Sectional Study

INTRODUCTION

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in the chronic kidney disease (CKD) population. CKD patients are more likely to die from CVD before ever reaching end-stage renal disease (ESRD). The study, therefore, seeks to identify the prevalence of risk factors of CVD in CKD patients such as systemic hypertension, anemia, dyslipidemia, hypoalbuminemia, albuminuria, and abnormal calcium/phosphate products.

METHODS

The study was a case-control cross-sectional study where one hundred fifty hypertensive CKD patients and age- and sex-matched hypertensive non-CKD subjects were consecutively enrolled at the renal unit of Delta State University Teaching Hospital (DELSUTH), Oghara.

RESULTS

The findings of the study revealed the mean ages of cases and controls to be 48.91±11.93 years and 51.0±15.45 years respectively (p-value 0.182). There was an equal number of males and females among the study group and controls (92 males and 58 females) making a male-to-female ratio of 3:2. The prevalence of CVD risk factors such as diabetes mellitus, hypercholesterolemia, hypertriglyceridemia, elevated low-density lipoprotein, anemia, hypocalcemia, hyperphosphatemia, albuminuria, and hypoalbuminemia was significantly higher among the CKD group compared to controls. Similarly, the prevalence of reduced high-density lipoprotein (HDL) was higher among cases than controls, the difference was however not statistically significant.

CONCLUSION

The study has shown that systemic hypertension, diabetes, anemia, dyslipidemia, hypoalbuminemia, albuminuria, and abnormal calcium/phosphate products increases the risk for CVD in the general population but is more expressed and significant in CKD patients.

An Updated Insight Into Molecular Mechanism of Hydrogen Sulfide in Cardiomyopathy and Myocardial Ischemia/Reperfusion Injury Under Diabetes

Cardiovascular diseases are the most common complications of diabetes, and diabetic cardiomyopathy is a major cause of people death in diabetes. Molecular, transcriptional, animal, and clinical studies have discovered numerous therapeutic targets or drugs for diabetic cardiomyopathy. Within this, hydrogen sulfide (H₂S), an endogenous gasotransmitter alongside with nitric oxide (NO) and carbon monoxide (CO), is found to play a critical role in diabetic cardiomyopathy. Recently, the protective roles of H₂S in diabetic cardiomyopathy have attracted enormous attention. In addition, H₂S donors confer favorable effects in myocardial infarction, ischaemia-reperfusion injury, and heart failure under diabetic conditions. Further studies have disclosed that multiplex molecular mechanisms are responsible for the protective effects of H₂S against diabetes-elicited cardiac injury, such as anti-oxidative, anti-apoptotic, anti-inflammatory, and anti-necrotic properties. In this review, we will summarize the current findings on H₂S biology and pharmacology, especially focusing on the novel mechanisms of H₂S-based protection against diabetic cardiomyopathy. Also, the potential roles of H₂S in diabetes-aggravated ischaemia-reperfusion injury are discussed.

Activation of HIF1α Rescues the Hypoxic Response and Reverses Metabolic Dysfunction in the Diabetic Heart

Type 2 diabetes (T2D) impairs hypoxia-inducible factor (HIF)1α activation, a master transcription factor that drives cellular adaptation to hypoxia. Reduced activation of HIF1α contributes to the impaired post-ischemic remodeling observed following myocardial infarction in T2D. Molidustat is an HIF stabilizer currently undergoing clinical trials for the treatment of renal anemia associated with chronic kidney disease; however, it may provide a route to pharmacologically activate HIF1α in the T2D heart. In human cardiomyocytes, molidustat stabilized HIF1α and downstream HIF target genes, promoting anaerobic glucose metabolism. In hypoxia, insulin resistance blunted HIF1α activation and downstream signaling, but this was reversed by molidustat. In T2D rats, oral treatment with molidustat rescued the cardiac metabolic dysfunction caused by T2D, promoting glucose metabolism and mitochondrial function, while suppressing fatty acid oxidation and lipid accumulation. This resulted in beneficial effects on post-ischemic cardiac function, with the impaired contractile recovery in T2D heart reversed by molidustat treatment. In conclusion, pharmacological HIF1α stabilization can overcome the blunted hypoxic response induced by insulin resistance. In vivo this corrected the abnormal metabolic phenotype and impaired post-ischemic recovery of the diabetic heart. Therefore, molidustat may be an effective compound to further explore the clinical translatability of HIF1α activation in the diabetic heart.

Coronary Large Conductance Ca2+-Activated K+ Channel Dysfunction in Diabetes Mellitus

Diabetes mellitus (DM) is an independent risk of macrovascular and microvascular complications, while cardiovascular diseases remain a leading cause of death in both men and women with diabetes. Large conductance Ca2+-activated K+ (BK) channels are abundantly expressed in arteries and are the key ionic determinant of vascular tone and organ perfusion. It is well established that the downregulation of vascular BK channel function with reduced BK channel protein expression and altered intrinsic BK channel biophysical properties is associated with diabetic vasculopathy. Recent efforts also showed that diabetes-associated changes in signaling pathways and transcriptional factors contribute to the downregulation of BK channel expression. This manuscript will review our current understandings on the molecular, physiological, and biophysical mechanisms that underlie coronary BK channelopathy in diabetes mellitus.

Disturbed Lipid Metabolism in Diabetic Patients with Manifest Coronary Artery Disease Is Associated with Enhanced Inflammation

Background: Diabetic vasculopathy plays an important role in the pathophysiology of coronary artery disease (CAD) with oxidative stress as a strong mediator. This study aims to elucidate the underlying pathomechanisms of diabetic cardiac vasculopathy leading to coronary disease with an emphasis on the role of oxidative stress. Therefore, novel insights into antioxidant pathways might contribute to new strategies in the treatment and prevention of diabetic CAD. Methods: In 20 patients with insulin-dependent or non-insulin dependent diabetes mellitus (IDDM/NIDDM) and 39 non-diabetic (CTR) patients, myocardial markers of oxidative stress, vasoactive proteins, endothelial nitric oxide synthase (eNOS), activated phosphorylated eNOS (p-eNOS), and antioxidant enzymes, e.g., tetrahydrobiopterin generating dihydrofolate reductase (DHFR), heme oxygenase (HO-1), as well as serum markers of inflammation, e.g., E-selectin, interleukin-6 (IL-6), and lipid metabolism, e.g., high- and low-density lipoptrotein (HDL- and LDL-cholesterol) were determined in specimens of right atrial tissue and in blood samples from type 2 diabetic and non-diabetic patients undergoing coronary artery bypass graft (CABG) surgery. Results: IDDM/NIDDM increased markers of inflammation (e.g., E-selectin, p = 0.005 and IL-6, p = 0.051), decreased the phosphorylated myocardial p-eNOS (p = 0.032), upregulated the myocardial stress response protein HO-1 (p = 0.018), and enhanced the serum LDL-/HDL-cholesterol ratio (p = 0.019). However, the oxidative stress markers in the myocardium and the expression of vasoactive proteins (eNOS, DHFR) showed only marginal adverse changes in patients with IDDM/NIDDM. Conclusion: Dyslipidemia and myocardial inflammation seem to be the major determinants of diabetic CAD complications. Dysregulation in pro-oxidative enzymes might be attributable to the severity of CAD and oxidative stress levels in all included patients undergoing CABG.

Diabetes Associated With Greater Ejection Fraction Improvement After Revascularization in Patients With Reduced Ejection Fraction

Objectives: To investigate the association between diabetes mellitus (DM) and ejection fraction (EF) improvement following revascularization in patients with coronary artery disease (CAD) and left ventricular (LV) dysfunction.

Background: Revascularization may improve outcomes of patients with LV dysfunction by improvement of EF. However, the determinants of EF improvement have not yet been investigated comprehensively.

Method: A cohort study (No. ChiCTR2100044378) of patient with repeated EF measurements after revascularization was performed. All patients had baseline EF ≤40%. Patients who had EF reassessment 3 months after revascularization were enrolled. Patients were categorized into EF unimproved (absolute increase in EF ≤5%) and improved group (absolute increase in EF >5%).

Results: A total of 974 patients were identified. 573 (58.8%) had EF improved. Patients with DM had greater odds of being in the improved group (odds ratio [OR], 1.42; 95% CI, 1.07–1.89; P = 0.014). 333 (34.2%) patients with DM had a greater extent of EF improvement after revascularization (10.5 ± 10.4 vs. 8.1 ± 11.2%; P = 0.002) compared with non-diabetic patients. The median follow-up time was 3.5 years. DM was associated with higher risk of overall mortality (hazard ratio [HR], 1.46; 95% CI, 1.02–2.08; P = 0.037). However, in EF improved group, the risk was similar between diabetic and non-diabetic patients (HR, 1.36; 95% CI, 0.80–2.32; P = 0.257).

Conclusions: Among patients with reduced EF, DM was associated with greater EF improvement after revascularization. Revascularization in diabetic patients might partially attenuate the impact of DM on adverse outcomes. Our findings imply the indication for revascularization in patients with LV dysfunction who present with DM.

Usefulness of Diastolic Function Score as a Predictor of Long-Term Prognosis in Patients With Acute Myocardial Infarction

Background: Left ventricular diastolic function (LVDF) evaluation using a combination of several echocardiographic parameters is an important predictor of adverse events in patients with acute myocardial infarction (AMI). To date, the clinical impact of each individual LVDF marker is well-known, but the clinical significance of the sum of the abnormal diastolic function markers and the long-term clinical outcome are not well-known. This study aimed to investigate the usefulness of LVDF score in predicting clinical outcomes of patients with AMI. Methods: LVDF scores were measured in a 2,030 patients with AMI who underwent successful percutaneous coronary intervention from 2012 to 2015. Four LVDF parameters (septal e' ≥ 7 cm/s, septal E/e' ≤ 15, TR velocity ≤ 2.8 m/s, and LAVI ≤ 34 ml/m²) were used for LVDF scoring. The presence of each abnormal LVDF parameter was scored as 1, and the total LVDF score ranged from 0 to 4. Mortality and hospitalization due to heart failure (HHF) in relation to LVDF score were evaluated. To compare the predictive ability of LVDF scores and left ventricular ejection fraction (LVEF) for mortality and HHF, receiver operating characteristic (ROC) curve and landmark analyses were performed. Results: Over the 3-year clinical follow-up, all-cause mortality occurred in 278 patients (13.7%), while 91 patients (4.5%) developed HHF. All-cause mortality and HHF significantly increased as LVDF scores increased (all-cause mortality-LVDF score 0: 2.3%, score 1: 8.8%, score 2: 16.7%, score 3: 31.8%, and score 4: 44.5%, p < 0.001; HHF-LVDF score 0: 0.6%, score 1: 1.8%, score 2: 6.3%, score 3: 10.3%, and score 4: 18.2%, p < 0.001). In multivariate analysis, a higher LVDF score was associated with significantly higher adjusted hazard ratios for all-cause mortality and HHF. In landmark analysis, LVDF score was a better predictor of long-term mortality than LVEF (area under the ROC curve: 0.739 vs. 0.640, p < 0.001). Conclusion: The present study demonstrated that LVDF score was a significant predictor of mortality and HHF in patients with AMI. LVDF scores are useful for risk stratification of patients with AMI; therefore, careful monitoring and management should be performed for patients with AMI with higher LVDF scores.

Cardiac Tissue Factor Regulates Inflammation, Hypertrophy, and Heart Failure in Mouse Model of Type 1 Diabetes

Patients with diabetes have an increased risk of heart failure (HF). Diabetes is highly prevalent in HF with preserved ejection fraction (HFpEF), which is on the rise worldwide. The role of diabetes in HF is less established, and available treatments for HF are not effective in patients with HFpEF. Tissue factor (TF), a transmembrane receptor, plays an important role in immune cell inflammation and atherothrombosis in diabetes. However, its role in diabetes-induced cardiac inflammation, hypertrophy, and HF has not been studied. In this study, we used wild-type (WT), heterozygous, and low-TF (with 1% human TF) mice to determine the role of TF in type 1 diabetes-induced HF. We found significant upregulation of cardiac TF mRNA and protein levels in diabetic WT hearts compared with nondiabetic controls. WT diabetic hearts also exhibited increased inflammation and cardiac hypertrophy versus controls. However, these changes in cardiac inflammation and hypertrophy were not found in low-TF mice with diabetes compared with their nondiabetic controls. TF deficiency was also associated with improved cardiac function parameters suggestive of HFpEF, which was evident in WT mice with diabetes. The TF regulation of inflammation and cardiac remodeling was further dependent on downstream ERK1/2 and STAT3 pathways. In summary, our study demonstrated an important role of TF in regulating diabetes-induced inflammation, hypertrophy, and remodeling of the heart leading to HFpEF.

Diabetes and Heart Failure: Multi-Omics Approaches

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

The Aging Vasculature: Glucose Tolerance, Hypoglycemia and the Role of the Serum Response Factor

The fastest growing demographic in the U.S. at the present time is those aged 65 years and older. Accompanying advancing age are a myriad of physiological changes in which reserve capacity is diminished and homeostatic control attenuates. One facet of homeostatic control lost with advancing age is glucose tolerance. Nowhere is this more accentuated than in the high proportion of older Americans who are diabetic. Coupled with advancing age, diabetes predisposes affected subjects to the onset and progression of cardiovascular disease (CVD). In the treatment of type 2 diabetes, hypoglycemic episodes are a frequent clinical manifestation, which often result in more severe pathological outcomes compared to those observed in cases of insulin resistance, including premature appearance of biomarkers of senescence. Unfortunately, molecular mechanisms of hypoglycemia remain unclear and the subject of much debate. In this review, the molecular basis of the aging vasculature (endothelium) and how glycemic flux drives the appearance of cardiovascular lesions and injury are discussed. Further, we review the potential role of the serum response factor (SRF) in driving glycemic flux-related cellular signaling through its association with various proteins.

Hyperglycemia and hyperlipidemia can induce morphophysiological changes in rat cardiac cell line

H9c2 cardiac cells were incubated under the control condition and at different hyperglycemic and hyperlipidemic media, and the following parameters were determined and quantified: a) cell death, b) type of cell death, and c) changes in cell length, width and height. Of all the proven media, the one that showed the greatest differences compared to the control was the medium glucose (G) 33 mM + 500 μM palmitic acid. This condition was called the hyperglycemic and hyperlipidemic condition (HHC). Incubation of H9c2 cells in HHC promoted 5.2 times greater total cell death when compared to the control. Of the total death ofthe HHC cells, 38.6% was late apoptotic and 8.3% early apoptotic. HHC also changes cell morphology. The reordering of the actin cytoskeleton and cell stiffness was also studied in control and HHC cells. The actin cytoskeleton was quantified and the number and distance of actin bundles were not the same in the control as under HHC. Young's modulus images show a map of cell stiffness. Cells incubated in HHC with the reordered actin cytoskeleton were stiffer than those incubated in control. The region of greatest stiffness was the peripheral zone of HHC cells (where the number of actin bundles was higher and the distance between them smaller). Our results suggest a correlation between the reordering of the actin cytoskeleton and cell stiffness. Thus, our study showed that HHC can promote morphophysiological changes in rat cardiac cells confirming that gluco-and lipotoxicity may play a central role in the development of diabetic cardiomyopathy.

Use of strain, strain rate, tissue velocity imaging, and endothelial function for early detection of cardiovascular involvement in young diabetics

Background:

Subtle structural and functional changes may precede the onset of overt global left ventricular (LV) dysfunction. Data pertaining to tissue velocity imaging (TVI)and strain imaging to assess regional myocardial function and flow mediated vasodilatation are limited in young patients with diabetes.

Materials:

Conventional echocardiography, TVI parameters along with strain (S), and strain rate (SR) were measured in 50 young diabetics (15.16 ± 2.95 years, mean HBA1c 8.15 ± 1.37 g %) and 25 controls (15.60 ± 2.51 years). Flow-mediated dilation (FMD), nitrate--mediated dilatation (NMD), and carotid intima–media thickness were also assessed.

Results:

Conventional echocardiography parameters were similar in patients and controls; however, deceleration time of the mitral inflow velocity (early deceleration time) was significantly shorter in patients when compared with controls (149.06 ± 31.66 vs. 184.56 ± 19.27 ms, P =0.001). Patients had lower strain values at the basal lateral LV (21.39 ± 4.12 vs. 23.78 ± 2.02; P =0.001), mid-lateral LV (21.43 ± 4.27 vs. 23.17 ± 1.92 P =0.02), basal septum (20.59 ± 5.28 vs. 22.91 ± 2.00; P = 0.01), and midseptum (22.06 ± 4.75 vs. 24.10 ± 1.99; P = 0.01) as compared to controls. SR at the basal and midsegments of the lateral LV wall and at the basal septum was also significantly lower in diabetic patients. Diabetic children also had endothelial dysfunction with significantly lower FMD (8.36 ± 4.27 vs. 10.57 ± 4.12, P = 0.04).

Conclusions:

LV strain indices and flow--mediated dilatation are impaired in asymptomatic children and adolescents with type 1 diabetes mellitus despite absence of overt heart failure and normal ejection fraction. Early detection of subclinical regional myocardial dysfunction by deformation analysis including strain and strain rate may be useful in the asymptomatic diabetic population.

Diet-induced obese mouse hearts tolerate an acute high-fatty acid exposure that also increases ischemic tolerance

An ischemic insult is accompanied by an acute increase in circulating fatty acid (FA) levels, which can induce adverse changes related to cardiac metabolism/energetics. Although chronic hyperlipidemia contributes to the pathogenesis of obesity-/diabetes-related cardiomyopathy, it is unclear how these hearts are affected by an acute high FA-load. We hypothesize that adaptation to chronic FA exposure enhances the obese hearts' ability to handle an acute high FA-load. Diet-induced obese (DIO) and age-matched control (CON) mouse hearts were perfused in the presence of low- or high FA-load (0.4 and 1.8 mM, respectively). Left ventricular (LV) function, FA oxidation rate, myocardial oxygen consumption, and mechanical efficiency were assessed, followed by analysis of myocardial oxidative stress, mitochondrial respiration, protein acetylation, and gene expression. Finally, ischemic tolerance was determined by examining LV functional recovery and infarct size. Under low-FA conditions, DIO hearts showed mild LV dysfunction, oxygen wasting, mechanical inefficiency, and reduced mitochondrial OxPhos. High FA-load increased FA oxidation rates in both groups, but this did not alter any of the above parameters in DIO hearts. In contrast, CON hearts showed FA-induced mechanical inefficiency, oxidative stress, and reduced OxPhos, as well as enhanced acetylation and activation of PPARα-dependent gene expression. While high FA-load did not alter functional recovery and infarct size in CON hearts, it increased ischemic tolerance in DIO hearts. Thus, this study demonstrates that acute FA-load affects normal and obese hearts differently and that chronically elevated circulating FA levels render the DIO heart less vulnerable to the disadvantageous effects of an acute FA-load.NEW & NOTEWORTHY An acute myocardial fat-load leads to oxidative stress, oxygen wasting, mechanical inefficiency, hyperacetylation, and impaired mitochondrial function, which can contribute to reduced ischemic tolerance. Following obesity/insulin resistance, hearts were less affected by a high fat-load, which subsequently also improved ischemic tolerance. This study highlights that an acute fat-load affects normal and obese hearts differently and that obesity renders hearts less vulnerable to the disadvantageous effects of an acute fat-load.

Diabetes mellitus exacerbates post-myocardial infarction heart failure by reducing sarcolipin promoter methylation

Aims

Sarcolipin (SLN) is a key regulator of sarcoplasmic reticulum calcium‐ATPase (SERCA)2a, which handles intracellular calcium re‐uptake. This study was aimed to investigate the involvement of SLN in post‐myocardial infarction (MI) heart failure (HF) in diabetes.

Methods and results

Diabetes/MI rat models were established. Altered SLN expression in diabetic hearts was screened out by microarray. A myocardiotropic viral vector was used to deliver siRNA to silence SLN. DNA methylation was evaluated by bisulfite sequencing. Cardiac functions were evaluated by invasive haemodynamic examinations. The SERCA2a activity, cytoplasmic calcium concentration ([Ca²⁺]_i), calcium spark, and myocyte contraction were detected. Correlation between HF and diabetes was analysed in a cohort consisted of 101 ST‐segment elevated myocardial infarction (STEMI) patients between 2017 and 2019 [53.54 ± 4.64 years old; 61.4% male gender; HbA1c% 6.15 ± 2.00; and left ventricular ejection fraction (LVEF%) 40.64 ± 3.20%]. SLN expression was evaluated in left ventricular tissue sample from six STEMI patients complicated with diabetes and six STEMI patients without diabetes. Expressions of DNA methyltransferase 1a and DNA methyltransferase 3 were reduced in diabetic hearts, leading to down‐regulation of SLN promoter methylation, resulting in increased SLN expression in rats. Impaired heart systolic functions were found in experimental diabetic MI rats, which were attenuated by SLN silencing. SERCA2a activity reduction and [Ca²⁺]_i elevation were attenuated by SLN silencing in diabetic animal hearts and high‐glucose incubated primary myocytes. SLN silencing suppressed calcium sparks and improved contraction and sarcoplasmic reticulum calcium re‐uptake in high‐glucose incubated primary myocytes. Expression of SLN was up‐regulated in LV sampled from STEMI patients complicated with diabetes compared with non‐diabetic ones (P < 0.05). LVEF% was reduced in STEMI patients complicated with diabetes compared with non‐diabetic ones (P < 0.01). HbA1c% and LVEF% was related (r = −0.218, P = 0.028). Increased HbA1c% was correlated with reduced LVEF% after adjustment for age, sex, body mass index, cigarette smoking, creatinine, UA, low density lipoprotein, K⁺, Na⁺, and troponin I (adjusted odds ration = 0.75, 95% confidence interval 0.62–0.90, P = 0.002).

Conclusions

Diabetes increases the vulnerability of STEMI patients to post‐MI HF by down‐regulating SLN promoter methylation, which further regulates SERCA2a activity via increasing cardiac SLN expression.

Cardioprotective effects of melatonin: Focusing on its roles against diabetic cardiomyopathy

Melatonin is a pineal-produced indole known for its anti-aging, antiapoptotic and antioxidant properties. In past decades, the protective potentials of melatonin for cardiovascular diseases, such as atherosclerosis and myocardial infarction, have been widely revealed, triggering more investigations focused on other cardioprotective effects of melatonin. Recently, the roles of melatonin in diabetic cardiomyopathy (DCM) have attracted increased attention. In this regard, researchers found that melatonin attenuated cardiac fibrosis and hypertrophy, thus interrupting the development of DCM. Retinoid-related orphan receptor α is a key melatonin receptor that contributed to the cardioprotective effect of melatonin in hearts with DCM. For the downstream mechanisms, the inhibition of mammalian STE20-like kinase 1 plays a pivotal role, which exerts antiapoptotic and proautophagic effects, thus enhancing cardiac tolerance in high-glucose conditions. In addition, other signalling mechanisms, such as sirtuin-1/peroxisome proliferator-activated receptor gamma-coactivator alpha and endoplasmic reticulum-related signalling, are also involved in the protective effects of melatonin on cardiomyocytes under diabetic conditions. This review will focus on the protective signalling mechanisms regulated by melatonin and provide a better understanding of the therapeutic applications of melatonin signalling in DCM.

Chronic inhibition of phosphodiesterase 5 with tadalafil affords cardioprotection in a mouse model of metabolic syndrome: role of nitric oxide

Patients with metabolic syndrome (MetS) often exhibit generalized endothelial and cardiac dysfunction with decreased nitric oxide (NO) production and/or bioavailability. Since phosphodiesterase 5 (PDE5) inhibitors restore NO signaling, we hypothesized that chronic treatment with long-acting PDE5 inhibitor tadalafil may enhance plasma NO levels and reduce cardiac dysfunction following ischemia/reperfusion (I/R) injury in C57BL/6NCrl-Leprdb-lb/Crl mice with MetS phenotypes. Adult male MetS mice were randomized to receive vehicle solvent or tadalafil (1 mg/kg,i.p.) daily for 28 days and C57BL/6NCrl mice served as healthy wild-type controls. After 28 days, cardiac function was assessed by echocardiography and hearts from a subset of mice were isolated and subjected to 30 min of global ischemia followed by 60 min of reperfusion (I/R) in ex vivo Langendorff mode. Body weight, blood lipids, and glucose levels were elevated in MetS mice as compared with wild-type controls. The dyslipidemia in MetS was ameliorated following tadalafil treatment. Although left ventricular (LV) systolic function was minimally altered in the MetS mice, there was a significant diastolic dysfunction as indicated by reduction in the ratio of peak velocity of early to late filling of the mitral inflow, which was significantly improved by tadalafil treatment. Post-ischemic cardiac function, heart rate, and coronary flow decreased significantly in MetS mice compared to wild-type controls, but preserved by tadalafil treatment. Myocardial infarct size was significantly smaller following I/R, which was associated with higher plasma levels of nitrate and nitrite in the tadalafil-treated MetS mice. In conclusion, tadalafil induces significant cardioprotective effects as shown by improvement of LV diastolic function, lipid profile, and reduced infarct size following I/R. Tadalafil treatment enhanced NO production, which may have contributed to the cardioprotective effects.

Gender difference in the impact of coexisting diabetes mellitus on long-term clinical outcome in people with heart failure: a report from the Korean Heart Failure Registry

AIM

Few data are available on the gender-related differences in the prognostic impact of diabetes in people with heart failure. This study was performed to investigate whether there is a gender difference in the association between diabetes and long-term clinical outcomes in people hospitalized for heart failure.

METHODS

A total of 3162 people hospitalized with heart failure (aged 67.4 ± 14.1 years, 50.4% females) from the data set of the nationwide registry were analysed. The primary endpoint was a composite of all-cause mortality and heart failure readmission.

RESULTS

People with diabetes (30.5% for males vs. 31.1% for females, P = 0.740) were older and had more unfavourable risk factors and laboratory findings than those without diabetes in both genders. During a median follow-up period of 549 days, there were 1418 cases of composite events (44.8%). In univariable analysis, the coexistence of diabetes was significantly associated with a higher incidence of composite events in both genders (P < 0.05 each for males and females). In multivariable analysis, the prognostic impact of diabetes on the development of composite events remained significant in females even after controlling for potential confounders (hazard ratio 1.43, 95% confidence intervals 1.12-1.84; P = 0.004). However, an independent association between diabetes and composite events was not seen in males in the same multivariable analysis (P > 0.05).

CONCLUSIONS

In people with heart failure, the impact of diabetes on long-term mortality and heart failure readmission seems to be stronger in females than in males. More careful and intensive management is needed especially in females with heart failure and diabetes.

Coronary artery disease in black African patients with diabetes: Insights from an Ivorian cardiac catheterization centre

BACKGROUND

Coronary angiography data are scarce for black patients with diabetes.

AIM

To assess coronary angiography findings in patients with diabetes at the Abidjan Heart Institute.

METHODS

This observational cross-sectional survey was conducted between 1 April 2010 and 31 December 2014. All patients admitted for known or suspected coronary artery disease who underwent coronary angiography were included in the Registre Prospectif des Actes de Cardiologie Interventionnelle de l'Institut de Cardiologie d'Abidjan. We analysed and compared coronary angiographical findings in patients with and without diabetes.

RESULTS

Eighty patients with diabetes were compared with 353 patients without diabetes. Patients with diabetes were significantly older (58.7±8.9 vs 52.1±11.5 years; P<0.001). Hypertension and hypertriglyceridaemia were significantly associated with diabetes (P<0.001 and P=0.04, respectively). A higher proportion of patients with diabetes had an abnormal coronary angiogram (85.0% vs 67.7%; P=0.002). Coronary artery disease in patients with diabetes was predominantly characterized by multivessel disease (P<0.001). Cardiovascular risk factors associated with diabetes influenced the severity of coronary lesions. A SYNTAX score≥33 was found in a higher proportion of patients with diabetes (12.5% vs 7.1%). In the multivariable logistic regression, after adjustment, age>60 years (hazard ratio 2.53, 95% confidence interval 1.59-4.04; P<0.001) and diabetes (hazard ratio 2.12, 95% confidence interval 1.26-3.57; P=0.004) were associated with multivessel coronary artery disease.

CONCLUSIONS

In our study, diabetes emerged as a risk factor for multivessel coronary artery disease. Future studies should help to define the long-term prognosis of these patients, and to assess the benefits of myocardial revascularization procedures.

The influence of anti-hyperglycemic drug therapy on cardiovascular and heart failure outcomes in patients with type 2 diabetes mellitus

Patients with type 2 diabetes mellitus (DM) are at a substantially increased risk of heart failure (HF) and HF mortality. Despite the lack of evidence that tight glycemic control reduces the incidence of cardiovascular (CV) events, a growing body of evidence suggests that the choice of glucose-lowering agents may influence outcomes including HF. Thiazolidinediones are associated with a significant risk of HF. For metformin, sulphonylureas and insulin, little data is available to indicate the impact on HF. The glucagon-like peptide-1 (GLP-1) agonists, liraglutide and semaglutide, have been shown to reduce major CV events, but did not affect rates of hospitalization for HF. Clinical trials have demonstrated diverse effects of Dipeptidyl peptidase-4 (DPP-4) inhibitors on HF; saxagliptin showed an increased risk of HF admissions, alogliptin was associated with higher rates of new HF admissions, while sitagliptin had a neutral effect. The sodium-glucose cotransporter 2 (SGLT2) inhibitors, empagliflozin and canagliflozin, have been recently shown to reduce the incidence of HF and cardiovascular mortality in patients with and without a history of HF. This review will summarize key findings of the impact of glucose-lowering agents on CV safety and HF-associated outcomes, present available data on the underlying mechanisms for the benefits of the SGLT2 inhibitors on HF, and discuss strategies to improve outcomes in patients with DM and high CV risk.

Fatty Acids Prevent Hypoxia-Inducible Factor-1α Signaling Through Decreased Succinate in Diabetes

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HIF-1α is activated following myocardial infarction, and is a critical transcription factor promoting survival in hypoxia.

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Type 2 diabetes blunts HIF-1α activation in ischemia and downstream adaptation to hypoxia.

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This effect is mediated by increased long-chain fatty acids, which prevent HIF-1α activation in hypoxia.

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Succinate promotes HIF-1α activation by inhibiting the regulatory HIF hydroxylases. Fatty acids decrease succinate concentrations in hypoxia, by blocking increased glycolysis and malate-aspartate shuttle activity.

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Pharmacologically activating HIF-1α or increasing succinate concentrations restores the hypoxic response and improves functional recovery post-ischemia in diabetes.

Hypoxia-inducible factor (HIF)-1α is essential following a myocardial infarction (MI), and diabetic patients have poorer prognosis post-MI. Could HIF-1α activation be abnormal in the diabetic heart, and could metabolism be causing this? Diabetic hearts had decreased HIF-1α protein following ischemia, and insulin-resistant cardiomyocytes had decreased HIF-1α-mediated signaling and adaptation to hypoxia. This was due to elevated fatty acid (FA) metabolism preventing HIF-1α protein stabilization. FAs exerted their effect by decreasing succinate concentrations, a HIF-1α activator that inhibits the regulatory HIF hydroxylase enzymes. In vivo and in vitro pharmacological HIF hydroxylase inhibition restored HIF-1α accumulation and improved post-ischemic functional recovery in diabetes.

Anti-inflammatory therapies in myocardial infarction: failures, hopes and challenges

In the infarcted heart, the damage-associated molecular pattern proteins released by necrotic cells trigger both myocardial and systemic inflammatory responses. Induction of chemokines and cytokines and up-regulation of endothelial adhesion molecules mediate leukocyte recruitment in the infarcted myocardium. Inflammatory cells clear the infarct of dead cells and matrix debris and activate repair by myofibroblasts and vascular cells, but may also contribute to adverse fibrotic remodelling of viable segments, accentuate cardiomyocyte apoptosis and exert arrhythmogenic actions. Excessive, prolonged and dysregulated inflammation has been implicated in the pathogenesis of complications and may be involved in the development of heart failure following infarction. Studies in animal models of myocardial infarction (MI) have suggested the effectiveness of pharmacological interventions targeting the inflammatory response. This article provides a brief overview of the cell biology of the post-infarction inflammatory response and discusses the use of pharmacological interventions targeting inflammation following infarction. Therapy with broad anti-inflammatory and immunomodulatory agents may also inhibit important repair pathways, thus exerting detrimental actions in patients with MI. Extensive experimental evidence suggests that targeting specific inflammatory signals, such as the complement cascade, chemokines, cytokines, proteases, selectins and leukocyte integrins, may hold promise. However, clinical translation has proved challenging. Targeting IL-1 may benefit patients with exaggerated post-MI inflammatory responses following infarction, not only by attenuating adverse remodelling but also by stabilizing the atherosclerotic plaque and by inhibiting arrhythmia generation. Identification of the therapeutic window for specific interventions and pathophysiological stratification of MI patients using inflammatory biomarkers and imaging strategies are critical for optimal therapeutic design.

Myocyte membrane and microdomain modifications in diabetes: determinants of ischemic tolerance and cardioprotection

Cardiovascular disease, predominantly ischemic heart disease (IHD), is the leading cause of death in diabetes mellitus (DM). In addition to eliciting cardiomyopathy, DM induces a ‘wicked triumvirate’: (i) increasing the risk and incidence of IHD and myocardial ischemia; (ii) decreasing myocardial tolerance to ischemia–reperfusion (I–R) injury; and (iii) inhibiting or eliminating responses to cardioprotective stimuli. Changes in ischemic tolerance and cardioprotective signaling may contribute to substantially higher mortality and morbidity following ischemic insult in DM patients. Among the diverse mechanisms implicated in diabetic impairment of ischemic tolerance and cardioprotection, changes in sarcolemmal makeup may play an overarching role and are considered in detail in the current review. Observations predominantly in animal models reveal DM-dependent changes in membrane lipid composition (cholesterol and triglyceride accumulation, fatty acid saturation vs. reduced desaturation, phospholipid remodeling) that contribute to modulation of caveolar domains, gap junctions and T-tubules. These modifications influence sarcolemmal biophysical properties, receptor and phospholipid signaling, ion channel and transporter functions, contributing to contractile and electrophysiological dysfunction, cardiomyopathy, ischemic intolerance and suppression of protective signaling. A better understanding of these sarcolemmal abnormalities in types I and II DM (T1DM, T2DM) can inform approaches to limiting cardiomyopathy, associated IHD and their consequences. Key knowledge gaps include details of sarcolemmal changes in models of T2DM, temporal patterns of lipid, microdomain and T-tubule changes during disease development, and the precise impacts of these diverse sarcolemmal modifications. Importantly, exercise, dietary, pharmacological and gene approaches have potential for improving sarcolemmal makeup, and thus myocyte function and stress-resistance in this ubiquitous metabolic disorder.

Myocardial injury in diabetic patients with multivessel coronary artery disease after revascularization interventions

BACKGROUND

Diabetic patients may be more susceptible to myocardial injury after coronary interventions. Thus, the aim of this study was to assess the release of cardiac biomarkers, CK-MB and troponin, and the findings of new late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) in patients with type 2 diabetes mellitus after elective revascularization procedures for multivessel coronary artery disease (CAD).

METHODS

Patients with multivessel CAD and preserved systolic ventricular function underwent either elective percutaneous coronary intervention (PCI), off-pump or on-pump bypass surgery (CABG). Troponin and CK-MB were systematically collected at baseline, 6, 12, 24, 36, 48 and 72 h after the procedures. CMR with LGE was performed before and after the interventions. Patients were stratified according to diabetes status at study entry. Biomarkers and CMR results were compared between diabetic and nondiabetics patients. Analyses of correlation were also performed among glycemic and glycated hemoglobin (A1c) levels and troponin and CK-MB peak levels. Patients were also stratified into tertiles of fasting glycemia and A1c levels and were compared in terms of periprocedural myocardial infarction (PMI) on CMR.

RESULTS

Ninety (44.5%) of the 202 patients had diabetes mellitus at study entry. After interventions, median peak troponin was 2.18 (0.47, 5.14) and 2.24 (0.69, 5.42) ng/mL (P = 0.81), and median peak CK-MB was 14.1 (6.8, 31.7) and 14.0 (4.2, 29.8) ng/mL (P = 0.43), in diabetic and nondiabetic patients, respectively. The release of troponin and CK-MB over time was statistically similar in both groups and in the three treatments, besides PCI. New LGE on CMR indicated that new myocardial fibrosis was present in 18.9 and 17.3% (P = 0.91), and myocardial edema in 15.5 and 22.9% (P = 0.39) in diabetic and nondiabetic patients, respectively. The incidence of PMI in the glycemia tertiles was 17.9% versus 19.3% versus 18.7% (P = 0.98), and in the A1c tertiles was 19.1% versus 13.3% versus 22.2% (P = 0.88).

CONCLUSIONS

In this study, diabetes mellitus did not add risk of myocardial injury after revascularization interventions in patients with multivessel coronary artery disease. Trial Registration Name of Registry: Evaluation of cardiac biomarker elevation after percutaneous coronary intervention or coronary artery bypass graft; URL: http://www.controlled-trials.com.ISRCTN09454308.

Placenta-Derived Adherent Stromal Cells Improve Diabetes Mellitus-Associated Left Ventricular Diastolic Performance

Left ventricular (LV) diastolic dysfunction is among others attributed to cardiomyocyte stiffness. Mesenchymal stromal cells (MSC) have cardiac-protective properties. We explored whether intravenous (i.v.) application of PLacenta-eXpanded (PLX) MSC-like cells (PLX) improves LV diastolic relaxation in streptozotocin (STZ)-induced diabetic mice and investigated underlying mechanisms. Diabetes mellitus was induced by STZ application (50 mg/kg body weight) during five subsequent days. One week after the first STZ injection, PLX or saline were i.v. applied. Two weeks later, mice were hemodynamically characterized and sacrificed. At this early stage of diabetic cardiomyopathy with low-grade inflammation and no cardiac fibrosis, PLX reduced LV vascular cell adhesion molecule-1, transforming growth factor-β1, and interferon-γ mRNA expression, induced the percentage of circulating regulatory T cells, and decreased the splenic pro-fibrotic potential in STZ mice. STZ + PLX mice exhibited higher LV vascular endothelial growth factor mRNA expression and arteriole density versus STZ mice. In vitro, hyperglycemic PLX conditioned medium restored the hyperglycemia-impaired tube formation and adhesion capacity of human umbelical vein endothelial cells (HUVEC) via increasing nitric oxide (NO) bioavailability. PLX further induced the diabetes-downregulated activity of the NO downstream protein kinase G, as well as of protein kinase A, in STZ mice, which was associated with a raise in phosphorylation of the titin isoforms N2BA and N2B. Concomitantly, the passive force was lower in single isolated cardiomyocytes from STZ + PLX versus from STZ mice, which led to an improvement of LV diastolic relaxation. We conclude that i.v. PLX injection improves diabetes mellitus-associated diastolic performance via decreasing cardiomyocyte stiffness. Stem Cells Translational Medicine 2017;6:2135-2145.

Association of down-regulation of calcitonin gene-related peptide and substance P with increase of myocardial vulnerability in diabetic neuropathic rats

Diabetic patients present high co-morbidities of neuropathy and severer consequences of coronary heart disease. But the pathological mechanism is still unclear. Here we investigated a potential association of diabetic impairment of sensory nerves with increase of vulnerability of myocardium in acute myocardial ischemia/reperfusion. A rat model of diabetes mellitus was induced by high fat and sugar diet plus a small dose of streptozotocin. Impairment of sensory nerves was evaluated by measurement of changes in tail flick latency to noxious thermal stimulation and calcitonin gene-related peptide (CGRP) and substance P (SP) in the dorsal root ganglia (DRG) and the myocardium of the heart were examined. The myocardial injury was examined by infarct size, apoptosis ratio of cardiomyocytes and cardiac troponin I in the animals underwent acute myocardial ischemia (for 30min) and reperfusion (for 120min). The effects of CGRP and SP on cardiomyocyte injury induced by high glucose and hypoxia/reoxygenation were tested in cultured myocytes. The diabetic animals presented significant elevation of noxious thermal threshold with obvious reduction of the contents of CGRP and SP in the DRG and the myocardium. Importantly, the diabetic animals showed significant increases of infarct size, myocyte apoptosis and serum cardiac troponin I after acute myocardial ischemia/reperfusion, compared to the non-diabetic control. Furthermore, exogenously administered CGRP and SP attenuated the myocyte injury induced by the high concentration of glucose and hypoxia/reoxygenation. These findings suggested that impairment of sensory nerves with significant reduction of CGRP and SP in DRG, ventricular myocardium and serum may be associated with increase of myocardial vulnerability in acute myocardial ischemia/reperfusion in streptozotocin-induced diabetic rats.

Identification of metabolic biomarkers in patients with type 2 diabetic coronary heart diseases based on metabolomic approach

Type 2 diabetic coronary heart disease (T2DM-CHD) is a kind of serious and complex disease. Great attention has been paid to exploring its mechanism; however, the detailed understanding of T2DM-CHD is still limited. Plasma samples from 15 healthy controls, 13 coronary heart disease (CHD) patients, 15 type 2 diabetes mellitus (T2DM) patients and 28 T2DM-CHD patients were analyzed in this research. The potential biomarkers of CHD and T2DM were detected and screened out by (1)H NMR-based plasma metabolic profiling and multivariate data analysis. About 11 and 12 representative metabolites of CHD and T2DM were identified respectively, mainly including alanine, arginine, proline, glutamine, creatinine and acetate. Then the diagnostic model was further constructed based on the previous metabolites of CHD and T2DM to detect T2DM-CHD with satisfying sensitivity of 92.9%, specificity of 93.3% and accuracy of 93.2%, validating the robustness of (1)H NMR-based plasma metabolic profiling to diagnostic strategy. The results demonstrated that the NMR-based metabolomics approach processed good performance to identify diagnostic plasma biomarkers and most identified metabolites related to T2DM and CHD could be considered as predictors of T2DM-CHD as well as the therapeutic targets for prevention, which provided new insight into diagnosing and forecasting of complex diseases.

Gender Discrepancy in Diabetic Patients Hospitalized With Heart Failure: Does Age Matter?

BACKGROUND

Gender discrepancy in the cardiovascular diseases has been evaluated in several studies. We studied the impact of gender disparity on the presentation and outcome of diabetic heart failure (DHF) patients.

METHODS

A retrospective analysis was conducted including all DHF patients admitted to the Heart Hospital between 1991 and 2013. Patients' demographics, presentation, management, and hospital outcomes were analyzed and compared based on gender and age.

RESULTS

Out of 8266 HF patients, 4684 (56.7%) were diabetic, of whom 1817 (39%) were females. Mean age was comparable in both genders. DHF female patients were more likely to be hypertensive (79% vs. 65%, P = 0.001) and obese (13% vs. 4.6%, P = 0.001). DHF females were less likely to receive beta-blockers and angiotensin-converting-enzyme inhibitors/angiotensinogen-receptor blockers (25% vs. 30%, P = 0.001, 54% vs. 57%, P = 0.01, respectively), but were more likely to be on insulin therapy (21% vs. 16%, P = 0.001). In-hospital atrial fibrillation (P =0.90), ventricular tachycardia (P = 0.07), stroke (P = 0.45), and cardiac arrest (P = 0.26) were comparable. Overall in-hospital mortality was comparable in both genders (P = 0.83). In age ≤50 years, male gender was associated with a 3-fold increase in death (13% vs. 4%, P = 0.01), however, this mortality difference disappeared in DHF patients aged >50 years (P = 0.62).

CONCLUSIONS

In DHF, female gender is characterized by having a high prevalence of metabolic syndrome components. Also, females are more likely to have better Left ventricular ejection fraction but less likely to receive cardiovascular evidence based medications. There is no significant difference in the overall hospital mortality between both genders, however, in the younger age; males have a significantly higher mortality.

Identifying disrupted pathways by tracking altered modules in type 2 DM-related heart failure

BACKGROUND

This study aimed to screen disrupted pathways in type 2 diabetes mellitus (T2DM) heart failure by systematically tracking the altered modules of reweighted protein-protein interaction (PPI) networks.

METHODS

We implemented systematic identification and comparison of modules across non-T2DM and T2DM heart failure subjects by integrating gene expression data and PPI networks. The PPI networks of non-T2DM heart failure and T2DM heart failure were constructed and reweighted by means of Spearman's correlation coefficient (SCC). Subsequently, a clique-merging algorithm was used to explore the modules in the PPI network, followed by the identification of disrupted modules based on a maximum-weight bipartite matching and sorting in descending order. Finally, pathway enrichment analyses were conducted for genes in disrupted modules to determine the biological pathways in T2DM heart failure.

RESULTS

By comparing the modules of non-T2DM heart failure and T2DM heart failure, 804 disrupted modules were explored. The genes in disrupted modules were significantly enriched in 39 categories (p < 1.00E-06). Of these, the most significant pathways were the focal adhesion, vascular endothelial growth factor (VEGF) signaling, and mitogen-activated protein kinase (MAPK) signaling pathways.

CONCLUSION

The identified disrupted pathways - focal adhesion, VEGF signaling, and MAPK signaling - might play important roles in the progression of T2DM heart failure.

Comparative cost-effectiveness of metformin-based dual therapies associated with risk of cardiovascular diseases among Chinese patients with type 2 diabetes: Evidence from a population-based national cohort in Taiwan

OBJECTIVE

To assess the cost-effectiveness of metformin-based dual therapies associated with cardiovascular disease (CVD) risk in a Chinese population with type 2 diabetes.

METHODS

We utilized Taiwan's National Health Insurance Research Database (NHIRD) 1997-2011, which is derived from the claims of National Health Insurance, a mandatory-enrollment single-payer system that covers over 99% of Taiwan's population. Four metformin-based dual therapy cohorts were used, namely a reference group of metformin plus sulfonylureas (Metformin-SU) and metformin plus acarbose, metformin plus thiazolidinediones (Metformin-TZD), and metformin plus glinides (Metformin-glinides). Using propensity scores, each subject in a comparison cohort was 1:1 matched to a referent. The effectiveness outcome was CVD risk. Only direct medical costs were included. The Markov chain model was applied to project lifetime outcomes, discounted at 3% per annum. The bootstrapping technique was performed to assess uncertainty in analysis.

RESULTS

Metformin-glinides was most cost-effective in the base-case analysis; Metformin-glinides saved $194 USD for one percentage point of reduction in CVD risk, as compared to Metformin-SU. However, for the elderly or those with severe diabetic complications, Metformin-TZD, especially pioglitazone, was more suitable; as compared to Metformin-SU, Metformin-TZD saved $840.1 USD per percentage point of reduction in CVD risk. Among TZDs, Metformin-pioglitazone saved $1831.5 USD per percentage point of associated CVD risk reduction, as compared to Metformin-rosiglitazone.

CONCLUSIONS

When CVD is considered an important clinical outcome, Metformin-pioglitazone is cost-effective, in particular for the elderly and those with severe diabetic complications.

A systematic review and meta-regression of temporal trends in the excess mortality associated with diabetes mellitus after myocardial infarction

BACKGROUND/OBJECTIVES

It is not well known whether the gap in outcomes after myocardial infarction (MI) between patients with and without diabetes mellitus (DM) has changed over time. We performed a systematic review and metaregression of temporal trends in the excess mortality associated with DM after MI.

METHODS

We searched the PubMed database for studies reporting mortality data according to diabetic status in patients hospitalized for MI or acute coronary syndromes (ACS). We included 139 studies/cohorts for analysis (432,066 diabetic patients and 1,182,108 nondiabetic patients).

RESULTS

When compared to their non-diabetic counterparts, patients with DM had an odds ratio (OR) [95% CI] of 1.66 [1.59-1.74] (P<0.0001) for early mortality, and of 1.86 [1.75-1.97] (P<0.0001) for 6-12months mortality. When all data from the 116 studies reporting early mortality were pooled, there was no significant relationship between calendar year and Log (OR). Likewise, when considering the 61 studies reporting 6-12months mortality, there was no significant relationship between calendar year and Log (OR). Similar to the overall pooled analysis, no significant relationship between inclusion year and Log (OR) for mortality in diabetic patients was observed in sensitivity analyses performed in studies with ST-elevation MI as inclusion criteria, in randomized trials, in studies including >2000 patients, and in studies with DM prevalence >20%.

CONCLUSIONS

We found no evidence for temporal changes in the incremental mortality risk associated with DM in the setting of MI. The improvements in management of MI patients during the last decades have not been associated with a reduction of the gap between diabetic and non-diabetic patients.

Subclinical Left Ventricular Longitudinal and Radial Systolic Dysfunction in Children and Adolescents with Type 1 Diabetes Mellitus

INTRODUCTION

There are few studies of subclinical systolic dysfunctions in children and adolescents with type 1 diabetes mellitus (DM), and so the available data are limited. The aim of this study was to determine early echocardiographic signs of LV systolic dysfunction in children and adolescents with type 1 DM using two-dimensional speckle tracking echocardiography (2DSTE).

MATERIAL AND METHODS

The study included 84 children and adolescents with type 1 DM and 32 sex-, age-, and body mass index-matched healthy subjects. The LV functions were assessed using conventional echocardiography, tissue Doppler imaging, and 2DSTE.

RESULTS

The results showed LV diastolic dysfunction as reflected by significantly increased A-wave velocity, decreased E/A ratio, and increased early filling deceleration time in the patients with diabetes (P = 0.02, P = 0.029, and P = 0.04; respectively). Compared with the control group, patients with diabetes showed significantly lower values for longitudinal systolic strain and strain rate in most segments of the LV; for radial strain values of the LV; for lateral circumferential strain and posterior and anterolateral circumferential strain rate of the LV; and for global longitudinal and radial strain of the LV. Global longitudinal and radial strain values of the LV were significantly lower among patients with poor glycemic control than in the control group.

CONCLUSION

In addition to diastolic dysfunction, LV longitudinal and radial function was found to be impaired in asymptomatic children and adolescents with type 1 DM who have normal LV ejection fraction by 2DSTE. Glycemic control may be the main risk factor for alteration of myocardial function.

Inflammation as a therapeutic target in myocardial infarction: learning from past failures to meet future challenges

In the infarcted myocardium, necrotic cardiomyocytes release danger signals, activating an intense inflammatory response. Inflammatory pathways play a crucial role in regulation of a wide range of cellular processes involved in injury, repair, and remodeling of the infarcted heart. Proinflammatory cytokines, such as tumor necrosis factor α and interleukin 1, are markedly upregulated in the infarcted myocardium and promote adhesive interactions between endothelial cells and leukocytes by stimulating chemokine and adhesion molecule expression. Distinct pairs of chemokines and chemokine receptors are implicated in recruitment of various leukocyte subpopulations in the infarcted myocardium. For more than the past 30 years, extensive experimental work has explored the role of inflammatory signals and the contributions of leukocyte subpopulations in myocardial infarction. Robust evidence derived from experimental models of myocardial infarction has identified inflammatory targets that may attenuate cardiomyocyte injury or protect from adverse remodeling. Unfortunately, attempts to translate the promising experimental findings to clinical therapy have failed. This review article discusses the biology of the inflammatory response after myocardial infarction, attempts to identify the causes for the translational failures of the past, and proposes promising new therapeutic directions. Because of their potential involvement in injurious, reparative, and regenerative responses, inflammatory cells may hold the key for design of new therapies in myocardial infarction.

A Higher Cardiothoracic Ratio Is Associated with 2-Year Mortality after Hemodialysis Initiation

A high cardiothoracic ratio (CTR) is indicative of a cardiac disorder. However, few reports have revealed an association between the CTR and mortality in patients starting hemodialysis (HD).

METHODS

Patients with HD initiation (n = 387; mean age, 66.7 ± 12.7 years) were divided into the following three groups according to their CTR at HD initiation: CTR <50%, 50% ≤ CTR < 55%, and CTR ≥55%. Kaplan-Meier analysis was performed to compare 2-year all-cause mortality among these groups. Furthermore, we investigated the factors affecting their 2-year mortality using a Cox proportional hazard regression analysis.

RESULTS

Sixty-five patients (17%) died within 2 years after HD initiation. Kaplan-Meier analysis showed that patients with CTR ≥55% had a higher mortality rate than those in the other groups. Cox proportional hazard regression analysis was performed using parameters with p values <0.1 among these three groups [sex, age, presence or absence of ischemic heart disease, hemoglobin levels, serum albumin levels, CTR, body mass index (BMI)] and confounding factors [presence or absence of diabetes mellitus, and estimated glomerular filtration rate (eGFR)]. Age, eGFR, BMI, and CTR ≥55% at HD initiation were identified as factors influencing 2-year mortality.

CONCLUSION

CTR >55% is one of the most important independent factors to affect 2-year all-cause mortality. Thus, confirming the cardiac condition of patients at HD initiation with a CTR >55% may improve their survival.

Comparison of Changes in Global Longitudinal Peak Systolic Strain After ST-Segment Elevation Myocardial Infarction in Patients With Versus Without Diabetes Mellitus

Global longitudinal strain (GLS) measured by 2-dimensional longitudinal speckle-tracking echocardiography may be a more sensitive measure of left ventricular (LV) mechanics than conventional LV ejection fraction (EF) to characterize adverse post-ST-segment elevation myocardial infarction (STEMI) remodeling. The aim of the present evaluation was to compare changes in LV GLS in patients with versus without diabetes after the first STEMI. Patients with first STEMI and diabetes (n = 143; age 64 ± 12 years; 68% men; 50% left anterior descending artery as culprit vessel) and 290 patients with first STEMI and without diabetes matched on age, gender, and infarct location were included. LV volumes and function and 2-dimensional LV GLS were measured after primary percutaneous coronary intervention (baseline) and at 6-month follow-up. At baseline, patients with and without diabetes had similar LVEF (46.8 ± 0.7% vs 48.0 ± 0.5%, p = 0.19) and infarct size (peak cardiac troponin T: 3.1 [1.2 to 6.5] vs 3.7 [1.3 to 7.3] μg/l, p = 0.10; peak creatine phosphokinase:1,120 [537 to 2,371] vs 1,291 [586 to 2,613] U/l, p = 0.17), whereas LV GLS was significantly more impaired in diabetic patients (-13.7 ± 0.3% vs -15.3 ± 0.2%, p <0.001). Although diabetic patients showed an improvement in LVEF over time similar to nondiabetic patients (52.0 ± 0.8% vs 53.1 ± 0.6%, p = 0.25), GLS remained more impaired at 6-month follow-up compared with nondiabetic patients (-15.8 ± 0.3% vs -17.3 ± 0.2%, p <0.001). After adjusting for clinical and echocardiographic characteristics, diabetes was independently associated with changes in GLS from baseline to 6-month follow-up (β 1.41, 95% confidence interval 0.85 to 1.96, p <0.001). In conclusion, after STEMI, diabetic patients show more impaired LV GLS at both baseline and follow-up compared with a matched group of patients without diabetes, despite having similar infarct size and LVEF at baseline and follow-up.

Heart failure in patients with diabetes undergoing primary percutaneous coronary intervention

INTRODUCTION

Diabetes mellitus is associated with increased risk after acute coronary syndromes. Primary percutaneous coronary intervention is the most effective method of reperfusion for acute ST-elevation myocardial infarction and can limit the ischaemic damage to the left ventricle. However, there are few data on the impact of diabetes mellitus on the risk of heart failure following primary percutaneous coronary intervention.

METHODS

We studied 958 ST-elevation myocardial infarction patients treated with primary percutaneous coronary intervention, of whom 263 (27.5%) had diabetes mellitus, with 67 (7.0%) treated with insulin. The primary end points of the study were re-admission for heart failure. Secondary end points were all-cause mortality and recurrent infarctions. The follow-up period was 5 years after hospital discharge.

RESULTS

The cumulative incidence of re-admission for heart failure was 8.4%, 15.2% and 26.7% in patients without diabetes mellitus, non-insulin-treated and insulin-treated diabetes mellitus, respectively. Compared with patients without diabetes mellitus, the adjusted hazard ratio for heart failure was 1.95 (95% confidence intervals 1.30-2.93) and 3.09 (95% confidence intervals 1.71-5.60) in non-insulin-treated and insulin-treated diabetes mellitus, respectively. The corresponding hazard ratios for mortality were 1.03 (95% confidence intervals 0.68-1.55) and 2.04 (95% confidence intervals 1.22-3.42), respectively. There was a J-shaped association between fasting glucose levels in the acute phase and risk of mortality (P=0.0001) and a direct association with heart failure (P=0.03).

CONCLUSION

Despite modern treatment of ST-elevation myocardial infarction and high levels of guideline-based medical care, diabetes mellitus had an independent adverse effect on the risk of re-admissions for heart failure, which was particularly high among insulin-treated patients.

Resveratrol ameliorates cardiac oxidative stress in diabetes through deacetylation of NFkB-p65 and histone 3

Resveratrol, a phytoalexin, has recently gained attention for protective effects against metabolic and cardiac diseases. The beneficial effects of resveratrol have been linked to sirtuin-1 (SIRT-1) activation. However, little is known about the effect of resveratrol in cardiac complications associated with diabetes. Here, we have demonstrated that resveratrol ameliorates cardiac hypertrophy, electrocardiographic abnormalities and oxidative stress in the fructose-fed diabetic rat heart. Mechanistic studies revealed that fructose feeding to Sprague-Dawley rats over a period of 8 weeks leads to cardiac hypertrophy and increased oxidative stress through increased activity of NADPH oxidase (NOX) and reactive oxygen species production. We found increased activity of nuclear factor kappa B (NFkB) p-65 along with decreased SIRT-1 activity in the diabetic heart. Resveratrol activates SIRT-1, which deacetylates NFkB-p65 at lysine 310 and histone 3 (H3) at lysine 9 position. SIRT1 activation leads to decreased binding of NFkB-p65 to DNA and attenuated cardiac hypertrophy and oxidative stress through reduced transcription of NADPH oxidase subunits. In vitro analysis also revealed that SIRT-1 activation by resveratrol is associated with decreased NFkB-p65 activity and NOX transcription. Similarly, knockdown or inhibition of SIRT1 in H9C2 cells increased acetylation of NFkB-p65 K310 and H3K9. Overall, our data demonstrated that SIRT-1 activation by resveratrol leads to deacetylation of both NFkB-p65 and H3, thereby attenuating cardiac oxidative stress and complications in diabetes.

The mitochondria in diabetic heart failure: from pathogenesis to therapeutic promise

SIGNIFICANCE

Diabetes is an important risk factor for the development of heart failure (HF). Given the increasing prevalence of diabetes in the population, strategies are needed to reduce the burden of HF in these patients.

RECENT ADVANCES

Diabetes is associated with several pathologic findings in the heart including dysregulated metabolism, lipid accumulation, oxidative stress, and inflammation. Emerging evidence suggests that mitochondrial dysfunction may be a central mediator of these pathologic responses. The development of therapeutic approaches targeting mitochondrial biology holds promise for the management of HF in diabetic patients.

CRITICAL ISSUES

Despite significant data implicating mitochondrial pathology in diabetic cardiomyopathy, the optimal pharmacologic approach to improve mitochondrial function remains undefined.

FUTURE DIRECTIONS

Detailed mechanistic studies coupled with more robust clinical phenotyping will be necessary to develop novel approaches to improve cardiac function in diabetes. Moreover, understanding the interplay between diabetes and other cardiac stressors (hypertension, ischemia, and valvular disease) will be of the utmost importance for clinical translation of scientific discoveries made in this field.

The Population-Based Risk of Need for Coronary Revascularization According to the Presence of Type 2 Diabetes Mellitus and History of Coronary Heart Disease in the Korean Population

BACKGROUND

Whether diabetic patients without a history of coronary heart disease (CHD) have the same risk of CHD events as non-diabetic patients with a history of CHD remains controversial. This study aimed to determine whether type 2 diabetes mellitus (T2DM) is a coronary heart disease (CHD) equivalent in the need for coronary revascularization procedures (RVs) in the Korean population.

METHODOLOGY/PRINCIPAL FINDINGS

We followed 2,168,698 subjects who had oral anti-diabetic drugs (OADs)-taking T2DM in 2008 and/or CHD in 2007-2008 (i.e., recent CHD). We used systematic datasets from the nationwide claims database of the Health Insurance Review and Assessment service of Korea, which is representative of the whole population of Korea, from January 2007 to December 2012. The primary study endpoint was the development of need for RVs (i.e., incident CHD) after January 2009 among three groups based on their status of T2DM and recent CHD, i.e., T2DM only, recent CHD only, and both T2DM and recent CHD. After adjustment for age and sex, patients with recent CHD only had 2.14 times the risk of incident CHD (95% CI, 2.11-2.18, P<0.001) compared with patients with T2DM only. Patients with both T2DM and recent CHD demonstrated approximately 2-fold increased risk of incident CHD compared with subjects with recent CHD only (95% CI, 1.75-1.82), while 4-fold increased risk compared with subjects with T2DM only (95% CI, 3.71-3.87). The risk of incident CHD also differed according to sex and age.

CONCLUSIONS/SIGNIFICANCE

This analysis of data from the nationwide claims database revealed that T2DM did not have a recent CHD equivalent risk in the Korean population. These results suggest that an appropriate strategy for the CHD risk stratification in diabetic patients should be adopted to manage this population.

Heart failure in diabetes: effects of anti-hyperglycaemic drug therapy

Individuals with diabetes are not only at high risk of developing heart failure but are also at increased risk of dying from it. Fortunately, antiheart failure therapies such as angiotensin-converting-enzyme inhibitors, β blockers and mineralocorticoid-receptor antagonists work similarly well in individuals with diabetes as in individuals without the disease. Response to intensive glycaemic control and the various classes of antihyperglycaemic agent therapy is substantially less well understood. Insulin, for example, induces sodium retention and thiazolidinediones increase the risk of heart failure. The need for new glucose-lowering drugs to show cardiovascular safety has led to the unexpected finding of an increase in the risk of admission to hospital for heart failure in patients treated with the dipeptidylpeptidase-4 (DPP4) inhibitor, saxagliptin, compared with placebo. Here we review the relation between glycaemic control and heart failure risk, focusing on the state of knowledge for the various types of antihyperglycaemic drugs that are used at present.

Improving diabetes diagnosis and management in myocardial infarction patients: overcoming clinical inertia

Diabetes is underdiagnosed and undertreated among acute myocardial infarction (AMI) patients. The early diagnosis and treatment of diabetes during AMI facilitates improved risk stratification, use of appropriate revascularization strategies and secondary prevention medications, and timely initiation of glycemic therapy. Accurate diagnostic methods, such as hemoglobin A1c, should be evaluated for hospitalized AMI patients. In addition, efforts to improve the uptake of diabetes screening and management in the hospitalized setting should occur. Possible actions include the use of clinical information systems to generate physician reminders for diabetes detection and management, audit and feedback programs, and professional society initiatives to address diabetes screening and therapy initiation through clinical guidelines and performance measures. Through the application of both these and other efforts listed in the manuscript, the rates of undiagnosed and undertreated diabetes among AMI patients can be significantly reduced, which would lead to an improvement in both diabetic and cardiovascular outcomes.

Adiponectin: Probe of the molecular paradigm associating diabetes and obesity

Type 2 diabetes is an emerging health challenge all over the world as a result of urbanization, high prevalence of obesity, sedentary lifestyle and other stress related factors compounded with the genetic prevalence. The health consequences and economic burden of the obesity and related diabetes mellitus epidemic are enormous. Different signaling molecules secreted by adipocytes have been implicated in the development of obesity and associated insulin resistance in type 2 diabetes. Human adiponectin, a 244-amino acid collagen-like protein is solely secreted by adipocytes and acts as a hormone with anti-inflammatory and insulin-sensitizing properties. Adiponectin secretion, in contrast to secretion of other adipokines, is paradoxically decreased in obesity which may be attributable to inhibition of adiponectin gene transcription. There are several mechanisms through which adiponectin may decrease the risk of type 2 diabetes, including suppression of hepatic gluconeogenesis, stimulation of fatty acid oxidation in the liver, stimulation of fatty acid oxidation and glucose uptake in skeletal muscle, and stimulation of insulin secretion. To date, no systematic review has been conducted that evaluate the potential importance of adiponectin metabolism in insulin resistance. In this review attempt has been made to explore the relevance of adiponectin metabolism for the development of diabetes mellitus. This article also identifies this novel target for prospective therapeutic research aiming successful management of diabetes mellitus.

Diabetes to cardiovascular disease: is depression the potential missing link?

The etiopathological consequences of diabetes and its imperative sequels have been explored extensively in the scientific arena of cardiovascular diabetology. Innumerable risk covariates and confounders have been delineated for the primary and secondary prevention of diabetes and cardiovascular diseases (CVD). However, an intricate interaction of depression on them has been largely overlooked. Depression influences and participates in each and every step that worsens the diabetic state for developing cardiovascular complications. The dilemma is that it coexists, remains silent and generally not considered as relevant clinical parameter amenable to intervention. In this review, it is highlighted that depression has strong association and linkages with both diabetes and CVD and it should be considered and diagnosed at every stage of the diabetes to CVD continuum. Careful attention to the diagnosis and management of these disease states would contribute in lessening the CVD burden of the society.

Hyperglycemic and hyperlipidemic conditions alter cardiac cell biomechanical properties

Currently, many diabetic cardiomyopathy (DC) studies focus on either in vitro molecular pathways or in vivo whole-heart properties such as ejection fraction. However, as DC is primarily a disease caused by changes in structural and functional properties, such studies may not precisely identify the influence of hyperglycemia or hyperlipidemia in producing specific cellular changes, such as increased myocardial stiffness or diastolic dysfunction. To address this need, we developed an in vitro approach to examine how structural and functional properties may change as a result of a diabetic environment. Particle-tracking microrheology was used to characterize the biomechanical properties of cardiac myocytes and fibroblasts under hyperglycemia or hyperlipidemic conditions. We showed that myocytes, but not fibroblasts, exhibited increased stiffness under diabetic conditions. Hyperlipidemia, but not hyperglycemia, led to increased cFos expression. Although direct application of reactive oxygen species had only limited effects that altered myocyte properties, the antioxidant N-acetylcysteine had broader effects in limiting glucose or fatty-acid alterations. Changes consistent with clinical DC alterations occur in cells cultured in elevated glucose or fatty acids. However, the individual roles of glucose, reactive oxygen species, and fatty acids are varied, suggesting multiple pathway involvement.