Role of microangiopathy in diabetic cardiomyopathy

Coronary microvascular dysfunction beyond the spectrum of chronic coronary syndromes

The prevalence of coronary microvascular dysfunction (CMD) beyond the spectrum of chronic coronary syndromes (CCS) is non-negligible, pertaining to pathophysiological and therapeutical implications. Thanks to the availability of accurate and safe non-invasive technique, CMD can be identified as a key player in heart failure, cardiomyopathies, Takotsubo syndrome, aortic stenosis. While CMD is widely recognized as a cause of myocardial ischemia leading to a worse prognosis even in the absence of obstructive coronary artery disease, the characterization of CMD patterns beyond CCS might provide valuable insights on the underlying disease progression, being potentially a "red flag" of adverse cardiac remodeling and a major determinant of response to therapy and outcomes. In this review, we aimed to provide an overview of the latest evidence on the prevalence, mechanistic and prognostic implications of CMD beyond the spectrum of CCS (i.e. heart failure, cardiomyopathies, Takotsubo syndrome, aortic stenosis).

Insulin-Heart Axis: Bridging Physiology to Insulin Resistance

Insulin signaling is vital for regulating cellular metabolism, growth, and survival pathways, particularly in tissues such as adipose, skeletal muscle, liver, and brain. Its role in the heart, however, is less well-explored. The heart, requiring significant ATP to fuel its contractile machinery, relies on insulin signaling to manage myocardial substrate supply and directly affect cardiac muscle metabolism. This review investigates the insulin-heart axis, focusing on insulin's multifaceted influence on cardiac function, from metabolic regulation to the development of physiological cardiac hypertrophy. A central theme of this review is the pathophysiology of insulin resistance and its profound implications for cardiac health. We discuss the intricate molecular mechanisms by which insulin signaling modulates glucose and fatty acid metabolism in cardiomyocytes, emphasizing its pivotal role in maintaining cardiac energy homeostasis. Insulin resistance disrupts these processes, leading to significant cardiac metabolic disturbances, autonomic dysfunction, subcellular signaling abnormalities, and activation of the renin-angiotensin-aldosterone system. These factors collectively contribute to the progression of diabetic cardiomyopathy and other cardiovascular diseases. Insulin resistance is linked to hypertrophy, fibrosis, diastolic dysfunction, and systolic heart failure, exacerbating the risk of coronary artery disease and heart failure. Understanding the insulin-heart axis is crucial for developing therapeutic strategies to mitigate the cardiovascular complications associated with insulin resistance and diabetes.

Association of non-insulin-based insulin resistance indices with disease severity and adverse outcome in idiopathic pulmonary arterial hypertension: a multi-center cohort study

BACKGROUND

Insulin resistance (IR) plays an important role in the pathophysiology of cardiovascular disease. Recent studies have shown that diabetes mellitus and impaired lipid metabolism are associated with the severity and prognosis of idiopathic pulmonary arterial hypertension (IPAH). However, the relationship between IR and pulmonary hypertension is poorly understood. This study explored the association between four IR indices and IPAH using data from a multicenter cohort.

METHODS

A total of 602 consecutive participants with IPAH were included in this study between January 2015 and December 2022. The metabolic score for IR (METS-IR), triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio, triglyceride and glucose (TyG) index, and triglyceride-glucose-body mass index (TyG-BMI) were used to quantify IR levels in patients with IPAH. The correlation between non-insulin-based IR indices and long-term adverse outcomes was determined using multivariate Cox regression models and restricted cubic splines.

RESULTS

During a mean of 3.6 years' follow-up, 214 participants experienced all-cause death or worsening condition. Compared with in low to intermediate-low risk patients, the TG/HDL-C ratio (2.9 ± 1.7 vs. 3.3 ± 2.1, P = 0.003) and METS-IR (34.5 ± 6.7 vs. 36.4 ± 7.5, P < 0.001) were significantly increased in high to intermediate-high risk patients. IR indices correlated with well-validated variables that reflected the severity of IPAH, such as the cardiac index and stroke volume index. Multivariate Cox regression analyses indicated that the TyG-BMI index (hazard ratio [HR] 1.179, 95% confidence interval [CI] 1.020, 1.363 per 1.0-standard deviation [SD] increment, P = 0.026) and METS-IR (HR 1.169, 95% CI 1.016, 1.345 per 1.0-SD increment, P = 0.030) independently predicted adverse outcomes. Addition of the TG/HDL-C ratio and METS-IR significantly improved the reclassification and discrimination ability beyond the European Society of Cardiology (ESC) risk score.

CONCLUSIONS

IR is associated with the severity and long-term prognosis of IPAH. TyG-BMI and METS-IR can independently predict clinical worsening events, while METS-IR also provide incremental predictive performance beyond the ESC risk stratification.

The double burden: type 1 diabetes and heart failure-a comprehensive review

Heart failure (HF) is increasing at an alarming rate, primary due to the rising in aging, obesity and diabetes. Notably, individuals with type 1 diabetes (T1D) face a significantly elevated risk of HF, leading to more hospitalizations and increased case fatality rates. Several risk factors contribute to HF in T1D, including poor glycemic control, female gender, smoking, hypertension, elevated BMI, and albuminuria. However, early and intensive glycemic control can mitigate the long-term risk of HF in individuals with T1D. The pathophysiology of diabetes-associated HF is complex and multifactorial, and the underlying mechanisms in T1D remain incompletely elucidated. In terms of treatment, much of the evidence comes from type 2 diabetes (T2D) populations, so applying it to T1D requires caution. Sodium-glucose cotransporter 2 inhibitors have shown benefits in HF outcomes, even in non-diabetic populations. However, most of the information about HF and the evidence from cardiovascular safety trials related to glucose lowering medications refer to T2D. Glycemic control is key, but the link between hypoglycemia and HF hospitalization risk requires further study. Glycemic variability, common in T1D, is an independent HF risk factor. Technological advances offer the potential to improve glycemic control, including glycemic variability, and may play a role in preventing HF. In summary, HF in T1D is a complex challenge with unique dimensions. This review focuses on HF in individuals with T1D, exploring its epidemiology, risk factors, pathophysiology, diagnosis and treatment, which is crucial for developing tailored prevention and management strategies for this population.

Preclinical Evidence for the Effectiveness of Mesenchymal Stromal Cells for Diabetic Cardiomyopathy: A Systematic Review and Meta-analysis

BACKGROUND

Diabetic cardiomyopathy (DCM) is a complication of diabetes mellitus that endangers human health. DCM results in cardiac dysfunction, which eventually progresses to heart failure. Mesenchymal stromal cells (MSCs), a type of multipotent stem cell, have shown promising therapeutic effects in various cardiovascular diseases and diabetic complications in preclinical studies due to their immunomodulatory and regenerative abilities. However, there is still a lack of evidence to summarize the effectiveness of MSCs in the treatment of DCM. Therefore, a meta-analysis and systematic review are warranted to evaluate the therapeutic potential of MSCs for DCM in preclinical studies.

METHODS

A comprehensive literature search in English or Chinese was conducted in PubMed, EMBASE, web of Science, Cochrane Library, and China National Knowledge Internet from inception to June 30, 2022. The summarized outcomes included echocardiography, morphology, and pathology. Data were independently extracted and analyzed by two authors. The software we adopted was Review Manager5.4.1. This systematic review was written in compliance with PRISMA 2020 and the review protocol was registered on PROSPERO, registration no. CRD42022350032.

RESULTS

We included 20 studies in our meta-analysis to examine the efficacy of MSCs in the treatment of DCM. The MSC-treated group showed a statistically significant effect on left ventricular ejection fraction (WMD=12.61, 95% CI 4.32 to 20.90, P=0.003) and short axis fractional shortening (WMD=6.84, 95% CI 4.09 to 9.59, P < 0.00001). The overall effects on the ratio of early to late diastolic mitral annular velocity, left ventricular end-diastolic pressure, maximum positive pressure development, maximum negative pressure development, left ventricular relaxation time constant, heart weight to body weight ratio, fibrosis area, and arteriole density were analyzed, suggesting that MSCs represent an effective therapy for the treatment of DCM.

CONCLUSION

Our results suggest a therapeutic role for MSCs in the treatment of DCM, and these results provide support for the use of MSCs in clinical trials of patients with DCM.

Association between Severity of Diabetic Retinopathy and Cardiac Function in Patients with Type 2 Diabetes

Background

The purpose of this research was to assess the relationship between the severity of diabetic retinopathy (DR) and indexes of left ventricle (LV) structure and function in type 2 diabetes mellitus (T2DM).

Methods

Retrospective analysis of 790 patients with T2DM and preserved LV ejection fraction. Retinopathy stages were classified as no DR, early nonproliferative DR, moderate to severe nonproliferative DR, or proliferative DR. The electrocardiogram was used to assess myocardial conduction function. Echocardiography was used to evaluate myocardial structure and function.

Results

Patients were divided into three groups based on the DR status: no DR group (NDR, n = 475), nonproliferative DR group (NPDR, n = 247), and proliferative DR group (PDR, n = 68). LV interventricular septal thickness (IVST) increased significantly with more severe retinopathy (NDR: 10.00 ± 1.09; NPDR: 10.42 ± 1.21; and PDR: 10.66 ± 1.58; P < 0.001). Multivariate logistic regression analysis showed that the significant correlation of IVST persisted between subjects with no retinopathy and proliferative DR (odds ratio = 1.35, P = 0.026). Indices of myocardial conduction function were assessed by electrocardiogram differences among groups of retinopathy (all P < 0.001). In multiple-adjusted linear regression analyses, the increasing degree of retinopathy was closely correlated with heart rate (β = 1.593, P = 0.027), PR interval (β = 4.666, P = 0.001), and QTc interval (β = 8.807, P = 0.005).

Conclusion

The proliferative DR was independently associated with worse cardiac structure and function by echocardiography. Furthermore, the severity of retinopathy significantly correlated with abnormalities of the electrocardiogram in patients with T2DM.

Association between triglyceride glucose index and subclinical left ventricular systolic dysfunction in patients with type 2 diabetes

BACKGROUND

The triglyceride glucose (TyG) index has been considered a new biomarker for the diagnosis of angiocardiopathy and insulin resistance. However, the association of the TyG index with subclinical left ventricular (LV) systolic dysfunction still lacks comprehensive exploration. This study was carried out to examine this relationship in patients with type 2 diabetes mellitus (T2DM).

METHODS

A total of 150 T2DM patients with preserved LV ejection fraction (LVEF ≥ 50%) from June 2021 to December 2021 were included in this study. The subclinical LV function was evaluated through global longitudinal strain (GLS), with the predefined GLS < 18% as the cutoff for subclinical LV systolic dysfunction. The TyG index calculation was obtained according to ln (fasting triglycerides (mg/dL) × fasting glucose (mg/dL)/2), which was then stratified into quartiles (TyG index-Q).

RESULTS

Analyses of clinical characteristics in the four TyG indexes-Q (Q1 (TyG index ≤ 8.89) n = 38, Q2 (8.89 < TyG index ≤ 9.44) n = 37, Q3 (9.44 < TyG index ≤ 9.83) n = 38, and Q4 (TyG index > 9.83) n = 37) were conducted. A negative correlation of the TyG index with GLS (r = -0.307, P < 0.001) was revealed according to correlation analysis. After gender and age were adjusted in multimodel logistic regression analysis, the higher TyG index (OR 6.86; 95% CI 2.44 to 19.30; P < 0.001, Q4 vs Q1) showed a significant association with GLS < 18%, which was still maintained after further adjustment for related clinical confounding factors (OR 5.23, 95% CI 1.12 to 24.51, p = 0.036, Q4 vs Q1). Receiver operator characteristic analysis indicated a diagnostic capacity of the TyG index for GLS < 18% (area under curve: 0.678; P < 0.001).

CONCLUSIONS

A higher TyG index had a significant association with subclinical LV systolic dysfunction in T2DM patients with preserved ejection fraction, and the TyG index may have the potential to exert predictive value for myocardial damage.

Assessment of subclinical left ventricular systolic dysfunction in patients with type 2 diabetes: Relationship with HbA1c and microvascular complications

BACKGROUND

We aimed to examine the association between glycated hemoglobin (HbA1c), microvascular complications, and subclinical left ventricular (LV) systolic dysfunction, and to determine the strength of the correlation in asymptomatic patients with type 2 diabetes mellitus (T2DM).

METHODS

Global longitudinal strain (GLS) was employed to assess the subclinical LV function of 152 enrolled T2DM patients with preserved LV ejection fraction, with the cutoff for subclinical LV systolic dysfunction predefined as GLS < 18%.

RESULTS

According to univariate analysis, the reduced GLS exhibited association with the clinical features including HbA1c, triglyceride, systolic blood pressure, fasting glucose, heart rate, diabetic retinopathy, and urinary albumin creatinine ratio (UACR) (all p < .05). After the factors of gender, age, and related clinical covariables adjusted, multiple logistic regression analysis revealed the HbA1c (odds ratio [OR] 1.66; 95% confidence interval [CI] 1.30-2.13; p < .001), UACR (OR 2.48; 95% CI 1.12-5.47; p = .025) and triglyceride (OR 1.84; 95% CI 1.12-3.03; p = .017) as the independent risk factors for the reduced GLS. Receiver operating characteristic curve showed a predictive value of the HbA1c for the subclinical LV systolic dysfunction (area under curve: 0.74; p < .001).

CONCLUSIONS

In asymptomatic T2DM patients, subclinical LV systolic dysfunction was associated with HbA1c, diabetic complications, and triglyceride. More prominently, HbA1c may exert a prognostic significance for the progression of myocardial damage.

Influence of fasting plasma glucose-lowering rate on BNP levels in type 2 diabetes mellitus patients with coronary microcirculation dysfunction

AIM

The aim was to analyze the influence of fasting plasma glucose-lowering rate (FPGLR) on plasma BNP levels in type 2 diabetes mellitus (T2DM) patients with coronary microcirculation dysfunction (CMD) and to determine the optimal FPGLR for these patients.

METHODS

A total of 170 T2DM patients who received intensive glucose-lowering therapy during hospitalization in the First Affiliated Hospital of Harbin Medical University were enrolled. Ninety-two patients with CMD and 78 patients without CMD were assigned to a study and a control group, respectively. The study group was stratified as S1 (4.1 ~ 6.0 mmol·L^-1·day^-1), S2 (2.1 ~ 4.0 mmol·L^-1·day^-1), and S3 (≤ 2.0 mmol·L^-1·day^-1) by different FPGLR, and the same in the control group (C1, C2, and C3). The plasma BNP levels with the same FPGLR were compared between the study and the control group, and patients with a different FPGLR in the study group were also compared.

RESULTS

In the study and the control group, the BNP level in S1 was significantly higher than that in C1 (87 vs. 12 pg/ml, P < 0.001), although there was no significant difference between S2 and C2, S3 and C3. In the study group, the BNP level in S1 was significantly higher than that in S2 (87 vs. 22 pg/ml, P < 0.001) and S3 (87 vs. 15 pg/ml, P < 0.001), but there was no significant difference between S2 and S3.

CONCLUSION

Rapid intensive glucose-lowering may lead to increased plasma BNP levels in T2DM patients with CMD. Optimal FPGLR for these patients was determined to be no more than 4.0 mmol·L^-1·day^-1.

Circulating cardiac biomarkers, structural brain changes, and dementia: Emerging insights and perspectives

Diseases of the heart and brain are strongly linked to each other, and cardiac dysfunction is associated with cognitive decline and dementia. This link between cardiovascular disease and dementia offers opportunities for dementia prevention through prevention and treatment of cardiovascular risk factors and heart disease. Increasing evidence suggests the clinical utility of cardiac biomarkers as risk markers for structural brain changes and cognitive impairment. We propose the hypothesis that structural brain changes are the link between impaired cardiac function, as captured by blood-based cardiac biomarkers, and cognitive impairment. This review provides an overview of the literature and illustrates emerging insights into the association of markers of hemodynamic stress (natriuretic peptides) and markers of myocardial injury (cardiac troponins) with imaging findings of brain damage and cognitive impairment or dementia. Based on these findings, we discuss potential pathophysiological mechanisms underlying the association of cardiac biomarkers with structural brain changes and dementia. We suggest testable hypotheses and a research plan to close the gaps in understanding the mechanisms linking vascular damage and neurodegeneration, and to pave the way for targeted effective interventions for dementia prevention. From a clinical perspective, cardiac biomarkers open the window for early identification of patients at risk of dementia, who represent a target population for preventive interventions targeting modifiable cardiovascular risk factors to avert cognitive decline and dementia.

Association of peripheral neuropathy with subclinical left ventricular dysfunction in patients with type 2 diabetes

OBJECTIVES

The impacts of diabetic peripheral neuropathy (DPN) on clinical manifestations of left ventricular (LV) function in patients suffering from type 2 diabetes mellitus (T2DM) and the preserved LV ejection fraction (LVEF) lack a full evaluation. This study was carried out to investigate the correlation of peripheral neuropathy with subclinical LV systolic dysfunction, accompanied by the exploration of the relevant clinical features of peripheral neuropathy in these patients.

METHODS

A retrospective analysis was conducted depending on the data of 101 consecutive inpatients with T2DM and preserved LVEF (all ≥ 50 %), without coronary artery disease and other histories of heart disease. All subjects received both a nerve conduction assessment and a speckle-tracking echocardiography examination. Global longitudinal strain (GLS) was conducted to assess the subclinical LV systolic function.

RESULTS

Forty-six (46 %) patients were diagnosed as DPN according to electrophysiological examination and clinical assessment. A significant difference was revealed in GLS between patients with and without DPN (16.5 ± 2.8 vs. 19.3 ± 3.4, p < 0.001). Multiple logistic regression analysis indicated GLS as one of the independent determinative factors for DPN (odds ratio, 0.68; P < 0.001). In addition, motor-sensory nerve conduction exhibited a significant positive correlation with GLS, which may not be revealed between the types of peripheral nerve damage.

CONCLUSIONS

Despite the preserved LVEF, the subclinical LV myocardial dysfunction may have occurred in T2DM patients with DPN. Peripheral nerve conduction was significantly correlated with GLS. An early assessment of nerve conduction may exert a dual warning significance for the progression of subclinical LV dysfunction in asymptomatic patients with T2DM.

Role of ADMA in the pathogenesis of microvascular complications in type 2 diabetes mellitus

Diabetic microangiopathy is a typical and severe problem in diabetics, including diabetic retinopathy, diabetic nephropathy, diabetic neuropathy, and diabetic cardiomyopathy. Patients with type 2 diabetes and diabetic microvascular complications have significantly elevated levels of Asymmetric dimethylarginine (ADMA), which is an endogenous inhibitor of nitric oxide synthase (NOS). ADMA facilitates the occurrence and progression of microvascular complications in type 2 diabetes through its effects on endothelial cell function, oxidative stress damage, inflammation, and fibrosis. This paper reviews the association between ADMA and microvascular complications of diabetes and elucidates the underlying mechanisms by which ADMA contributes to these complications. It provides a new idea and method for the prevention and treatment of microvascular complications in type 2 diabetes.

Nomogram based on multimodal echocardiography for assessing the evolution of diabetic cardiomyopathy in diabetic patients with normal cardiac function

Background

Diabetic cardiomyopathy (DCM) remains asymptomatic for many years until progression to asymptomatic left ventricular diastolic dysfunction (ALVDD), a subclinical cardiac abnormality present in early-stage DCM. Because LV function in patients with type 2 diabetes mellitus (T2DM) may be subtly altered long before the onset of ALVDD, quantitative assessment of the risk of progression to early-stage DCM in T2DM patients with normal hearts is critical for delaying or even reversing DCM.

Objective

This study aimed to establish a nomogram with the aid of DCM characteristics revealed by multimodal echocardiography to assess the likelihood of the progression to early-stage DCM in T2DM patients with normal cardiac function.

Methods

Of the 423 T2DM patients enrolled, 302 were included in the training cohort and 121 in the validation cohort. The clinical characteristics, biochemical data, and multimodal echocardiographic parameters were collected. In the training cohort, the screened correlates of ALVDD were utilized to develop a nomogram for estimating the risk coefficient for early-stage DCM. This model was validated both in the training and validation cohorts.

Results

ALVDD was independently correlated with the number of comorbidities [with one comorbidity: odds ratio (OR) = 3.009; with two comorbidities: OR = 4.026], HbA1c (OR = 1.773), myocardial blood flow (OR = 0.841), and global longitudinal strain (OR = 0.856) (all P < 0.05). They constituted a nomogram to visualize the likelihood of DCM development in T2DM patients with normal cardiac function. The model was validated to present strong discrimination and calibration, and obtained clinical net benefits both in the training and validation cohorts.

Conclusion

We constructed and validated a nomogram to estimate the likelihood of developing early-stage DCM in T2DM patients with normal cardiac function. The alteration of the nomogram-predicted risk coefficient is expected to be proposed as a therapeutic target to slow or stop DCM progression.

The Protective Effects of Neurotrophins and MicroRNA in Diabetic Retinopathy, Nephropathy and Heart Failure via Regulating Endothelial Function

Diabetes mellitus is a common disease affecting more than 537 million adults worldwide. The microvascular complications that occur during the course of the disease are widespread and affect a variety of organ systems in the body. Diabetic retinopathy is one of the most common long-term complications, which include, amongst others, endothelial dysfunction, and thus, alterations in the blood-retinal barrier (BRB). This particularly restrictive physiological barrier is important for maintaining the neuroretina as a privileged site in the body by controlling the inflow and outflow of fluid, nutrients, metabolic end products, ions, and proteins. In addition, people with diabetic retinopathy (DR) have been shown to be at increased risk for systemic vascular complications, including subclinical and clinical stroke, coronary heart disease, heart failure, and nephropathy. DR is, therefore, considered an independent predictor of heart failure. In the present review, the effects of diabetes on the retina, heart, and kidneys are described. In addition, a putative common microRNA signature in diabetic retinopathy, nephropathy, and heart failure is discussed, which may be used in the future as a biomarker to better monitor disease progression. Finally, the use of miRNA, targeted neurotrophin delivery, and nanoparticles as novel therapeutic strategies is highlighted.

Long term risk of heart failure in individuals with childhood-onset type 1 diabetes

BACKGROUND

We aimed to evaluate the risk of heart failure in young adults with childhood-onset type 1 diabetes from the Pittsburgh Epidemiology of Diabetes Complications (EDC) Study. We also examined risk factors and microvascular disease burden associated with the incidence of heart failure.

METHODS

Participants in the EDC study without known baseline heart failure (n = 655) were enrolled and then followed for 25 years. "Any" heart failure comprised the underlying cause of death, primary reason for hospitalization, EDC clinic examination findings or self-report of a physician diagnosis. "Hard" heart failure was determined only by the underlying cause of death or primary reason for hospitalization. Incidence rates for heart failure were estimated using Poisson models. Cox models were constructed to examine the associations between risk factors and microvascular disease burden with incident heart failure.

RESULTS

The mean baseline age and diabetes duration were 27(8) years and 19 (8) years. Incidence for any and hard heart failure were 3.4 and 1.8/1000 person-years. Diabetes duration, ever smoking and triglycerides were significant risk factors of any heart failure; longer diabetes duration, lower estimated glomerular filtration rate and higher white blood cell count significantly predicted hard heart failure. A gradient association was observed between the number of microvascular disease (from 0 to 3) and "hard" heart failure endpoint but not "any" clinically defined heart failure.

CONCLUSION

Young adults with long-duration type 1 diabetes had a high risk of heart failure. As microvascular disease burden increases so does the risk of heart failure independently of diabetes duration, A1c and coronary artery disease.

MicroRNA-223-3p promotes pyroptosis of cardiomyocyte and release of inflammasome factors via downregulating the expression level of SPI1 (PU.1)

Diabetic cardiomyopathy (DCM) is a common heart disease in patients with diabetes mellitus (DM), and is sometimes its main cause of death. Among all the causes of DCM, myocardial cell death is considered to be the most basic pathological change. Furthermore, studies have shown that pyroptosis, the pro-inflammatory programmed cell death, contributes to the progress of DCM. MicroRNAs (miRNAs) also have been proved to take part in the formation of DCM. However, it is not clear whether and how miRNAs regulate myocardial cell pyroptosis in DCM development. In our study, the results showed that the expression of miR-223-3p was significantly increased in cardiomyocytes induced by high glucose, whereas the down-regulation of miR-223-3p weakened it. To understand the the signal transduction mechanism of miR-223-3p leading to pyroptosis, we found inhibition of miR-223-3p expression down-reguulated caspase-1, pro-inflammatory cytokines IL-1β and other pyroptosis-associated poteins. Moreover, miR-223-3p repressed SPI1 expression. Furthermore, we silenced SPI1 with siRNA to mimick the effect of miR-223-3p, up-regulating the expression of caspase-1 and resulting to pyroptosis. The above findings inspired us to propose a new signaling pathway to regulate scoria of cardiomyocytes under hyperglycemia: miR-223-3p↑→ SPI1↓→ caspase-1↑ → IL-1β and other pyroptosis-associated poteins↑→ pyroptosis↑. In summary, miR-223-3p could be a potential therapeutic target for DCM.

Microvascular Dysfunction in Skeletal Muscle Precedes Myocardial Vascular Changes in Diabetic Cardiomyopathy: Sex-Dependent Differences

Aim

To uncover sex-related microvascular abnormalities that underlie the early presentation of reduced perfusion in leg skeletal muscle in a type II rat model of diabetic cardiomyopathy.

Methods and Results

Diabetes was induced using a non-obese, diet-based, low-dose streptozotocin model in adult female (18 diabetic, 9 control) and male rats (29 diabetic, 11 control). Time-course monitoring over 12 months following diabetes induction was performed using echocardiography, treadmill exercise, photoacoustic imaging, flow-mediated dilation (FMD), histopathology, and immunohistochemistry. Diabetic rats maintained normal weights. Hypertension appeared late in both diabetic males (7 months) and females (10 months), while only diabetic males had elevated cholesterol (7 months). On echocardiography, all diabetic animals maintained normal ejection fraction and exhibited diastolic dysfunction, mild systolic dysfunction, and a slightly enlarged left ventricle. Exercise tolerance declined progressively and early in males (4 months), later in females (8 months); FMD showed lower baseline femoral arterial flow but unchanged reactivity in both sexes (5 months); and photoacoustic imaging showed lower tissue oxygen saturation in the legs of diabetic males (4 months) and diabetic females (10 months). Myocardial perfusion was normal in both sexes. Histopathology at the final timepoint of Month 10 (males) and Month 12 (females) revealed that myocardial microvasculature was normal in both vessel density and structure, thus explaining normal perfusion on imaging. However, leg muscle microvasculature exhibited perivascular smooth muscle thickening around small arterioles in diabetic females and around large arterioles in diabetic males, explaining the depressed readings on photoacoustic and FMD. Histology also confirmed the absence of commonly reported HFpEF markers, including microvessel rarefaction, myocardial fibrosis, and left ventricular hypertrophy.

Conclusion

Exercise intolerance manifesting early in the progression of diabetic cardiomyopathy can be attributed to decreased perfusion to the leg skeletal muscle due to perivascular smooth muscle thickening around small arterioles in females and large arterioles in males. This microvascular abnormality was absent in the myocardium, where perfusion levels remained normal throughout the study. We conclude that although skeletal muscle microvascular dysfunction of the vasculature presents at different levels depending on sex, it consistently presents early in both sexes prior to overt cardiac changes such as rarefaction, fibrosis, or hypertrophy.

Cellular interplay between cardiomyocytes and non-myocytes in diabetic cardiomyopathy

Patients with Type 2 diabetes mellitus (T2DM) frequently exhibit a distinctive cardiac phenotype known as diabetic cardiomyopathy. Cardiac complications associated with T2DM include cardiac inflammation, hypertrophy, fibrosis and diastolic dysfunction in the early stages of the disease, which can progress to systolic dysfunction and heart failure. Effective therapeutic options for diabetic cardiomyopathy are limited and often have conflicting results. The lack of effective treatments for diabetic cardiomyopathy is due in part, to our poor understanding of the disease development and progression, as well as a lack of robust and valid preclinical human models that can accurately recapitulate the pathophysiology of the human heart. In addition to cardiomyocytes, the heart contains a heterogeneous population of non-myocytes including fibroblasts, vascular cells, autonomic neurons and immune cells. These cardiac non-myocytes play important roles in cardiac homeostasis and disease, yet the effect of hyperglycaemia and hyperlipidaemia on these cell types are often overlooked in preclinical models of diabetic cardiomyopathy. The advent of human induced pluripotent stem cells provides a new paradigm in which to model diabetic cardiomyopathy as they can be differentiated into all cell types in the human heart. This review will discuss the roles of cardiac non-myocytes and their dynamic intercellular interactions in the pathogenesis of diabetic cardiomyopathy. We will also discuss the use of sodium-glucose cotransporter 2 inhibitors as a therapy for diabetic cardiomyopathy and their known impacts on non-myocytes. These developments will no doubt facilitate the discovery of novel treatment targets for preventing the onset and progression of diabetic cardiomyopathy.

Impact of diabetes on coronary physiology evaluated by quantitative flow ratio in patients who underwent percutaneous coronary intervention

Aims/Introduction

There are mixed opinions on the influence of diabetes on the prognosis of patients receiving percutaneous coronary intervention (PCI). Therefore, in this study, the quantitative flow ratio (QFR), an emerging technology of functional evaluation, was used to explore the impact of diabetes on coronary physiology in patients who underwent PCI.

Materials and Methods

Patients who underwent successful PCI and a 1‐year angiographic follow up were retrospectively screened and analyzed by the QFR. Based on the presence or absence of diabetes, 677 enrolled patients (794 vessels) were classified into a diabetes group (211 patients, 261 vessels) and a non‐diabetes group (466 patients, 533 vessels). The results of QFR analysis and clinical outcomes were compared between the two groups.

Results

The two groups reached a similar level of post‐PCI QFR (0.95 ± 0.09 vs 0.96 ± 0.06, P = 0.292). However, at the 1‐year follow up, the QFR was lower (0.93 ± 0.11 vs 0.96 ± 0.07, P < 0.001), and the degree of QFR decline was more obvious (−0.024 ± 0.090 vs −0.008 ± 0.070, P = 0.023) in the diabetes group. Additionally, diabetes was independently associated with functional restenosis (odds ratio 2.164, 95% confidence interval 1.210–3.870, P = 0.009) and target vessel failure (odds ratio 2.654, 95% confidence interval 1.405–5.012, P = 0.003).

Conclusion

As evaluated by the QFR, patients with diabetes received less coronary physiological benefit from PCI, which was consistent with their clinical outcomes.

Correlation Between Retinopathy and Coronary Microcirculation Dysfunction in Patients with Type 2 Diabetes Mellitus

Purpose

The aim of this study is to evaluate the correlation between retinopathy and coronary microcirculation dysfunction (CMD) in type 2 diabetes mellitus (T2DM) patients.

Methods

198 T2DM patients with left ventricular ejection fraction (LVEF)>50%, no epicardial coronary artery stenosis diagnosis by coronary angiography (CAG) and successfully completed coronary blood flow reserve (CFR) test and laboratory examination were enrolled, and fundus examination was performed on all participants. Two groups were divided according to CFR value, including 86 patients with CMD (CFR≤2.5) in study group and 112 patients without CMD (CFR>2.5) in control group. The composition of various retinopathy in two groups was observed, and the correlation between retinopathy and CMD was analyzed using ordered logistic regression.

Results

There were 13 cases with arteriovenous (A/V) nicking, 4 cases with proliferative diabetic retinopathy (PDR), 14 cases with non-proliferative diabetic retinopathy (NPDR), 17 cases with diabetic retinopathy (DR) with A/V nicking, 38 cases without retinopathy in study group, and 18 cases, 7 cases, 20 cases, 4 cases and 63 cases for each in control group. After adjustment for age, gender, hypertension, diabetes duration, dyslipidemia, glycosylated hemoglobin (HbA1c), body mass index (BMI), A/V nicking, PDR and NPDR, the diference of DR with A/V nicking between study and control group remained statistically signifcant (OR 2.0, 95% CI 0.79 to 3.21, p = 0.001).

Conclusion

DR with A/V nicking could be used as an independent predictor of T2DM patients with CMD. CFR testing should be performed on patients with this kind of eye sign, even if they do not have any symptoms of heart disease. Meanwhile, DR with A/V nicking might be served as a reference indicator of CMD in T2DM patients with chest pain who were unable to be tested for CFR.

Interplay of Oxidative Stress and Necrosis-like Cell Death in Cardiac Ischemia/Reperfusion Injury: A Focus on Necroptosis

Extensive research work has been carried out to define the exact significance and contribution of regulated necrosis-like cell death program, such as necroptosis to cardiac ischemic injury. This cell damaging process plays a critical role in the pathomechanisms of myocardial infarction (MI) and post-infarction heart failure (HF). Accordingly, it has been documented that the modulation of key molecules of the canonical signaling pathway of necroptosis, involving receptor-interacting protein kinases (RIP1 and RIP3) as well as mixed lineage kinase domain-like pseudokinase (MLKL), elicit cardioprotective effects. This is evidenced by the reduction of the MI-induced infarct size, alleviation of myocardial dysfunction, and adverse cardiac remodeling. In addition to this molecular signaling of necroptosis, the non-canonical pathway, involving Ca2+/calmodulin-dependent protein kinase II (CaMKII)-mediated regulation of mitochondrial permeability transition pore (mPTP) opening, and phosphoglycerate mutase 5 (PGAM5)–dynamin-related protein 1 (Drp-1)-induced mitochondrial fission, has recently been linked to ischemic heart injury. Since MI and HF are characterized by an imbalance between reactive oxygen species production and degradation as well as the occurrence of necroptosis in the heart, it is likely that oxidative stress (OS) may be involved in the mechanisms of this cell death program for inducing cardiac damage. In this review, therefore, several observations from different studies are presented to support this paradigm linking cardiac OS, the canonical and non-canonical pathways of necroptosis, and ischemia-induced injury. It is concluded that a multiple therapeutic approach targeting some specific changes in OS and necroptosis may be beneficial in improving the treatment of ischemic heart disease.

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.

Characteristics of Myocardial Perfusion in Type 2 Diabetes Mellitus and Its Association with Left Ventricular Diastolic Dysfunction: A Study of Myocardial Contrast Echocardiography

Background

Diabetic cardiomyopathy (DCM) will gradually progress to heart failure without intervention. The timely identification of left ventricular diastolic dysfunction (LVDD) in the early stage and active intervention helps delay the onset of heart failure. Although myocardial contrast echocardiography (MCE) allows an accurate evaluation of myocardial perfusion (MP), the characteristics of MP in early-stage or even sub-clinical LVDD are still unclear.

Objective

This study aims to reveal the characteristics of MP in asymptomatic and normotensive patients with type 2 diabetes mellitus (T2DM) using MCE and investigate its association with LVDD development.

Methods

A total of 327 T2DM patients were retrospectively analyzed. Patients diagnosed with LVDD were included in the LVDD+ group (n = 76), and those with normal left ventricular diastolic function were included in the LVDD- group (n = 251). The clinical characteristics, general echocardiographic findings, and MCE parameters were compared between the two groups. The accuracy of MCE parameters in the diagnosis of LVDD and their correlations with characteristics of T2DM were evaluated.

Results

In the LVDD+ group, the A×β (derived from the replenishment curve of MCE, presenting myocardial blood flow) was significantly lower, and the HbA1c and diabetes duration were significantly higher compared to the LVDD- group (all P < 0.05). The decrease of A×β helped warn the occurrence of LVDD although it was not suitable for the independent diagnosis of LVDD (AUC = 0.745). A×β was negatively correlated with diabetes duration and HbA1c (r = -0.350 and -0.226, both P < 0.001).

Conclusion

MCE was feasible for detecting MP abnormalities in asymptomatic T2DM patients. Although the A×β values of T2DM patients with subclinical LVDD were better than those with diagnosed LVDD, it impaired with the increase of HbA1c and diabetes duration. It suggested that MCE might be useful for monitoring glycemic control in T2DM patients with DCM.

Disturbed Glucose Metabolism and Left Ventricular Geometry in the General Population

Background: This study sought to investigate the prevalence and clinical outcome of left ventricular (LV) geometry in prediabetes and type 2 diabetes mellitus (T2DM) and the impact of glucose metabolism on the incidence of left ventricular hypertrophy (LVH). Methods: 15,010 subjects (35–74 years) of the population-based Gutenberg Health Study were categorized into euglycemia, prediabetes, and T2DM according to clinical and metabolic (HbA1c) information. Clinical outcome was assessed via structured follow-up. Results: The study comprised 12,121 individuals with euglycemia (81.6%), 1415 with prediabetes (9.5%), and 1316 with T2DM (8.9%). Prevalence of LVH increased from euglycemia (10.2%) over prediabetes (17.8%) to T2DM (23.8%). Prediabetes and T2DM were associated with increased LV mass index (prediabetes: β1.3 (95% CI 0.78–1.81), p < 0.0001; T2DM: β2.37 (95% CI 1.81; 2.92), p < 0.0001) independent of age, sex, and cardiovascular risk factors (CVRF). The frequency of LVH was related to the presence of T2DM (prevalence ratio (PR)T2DM 1.2 (95% CI 1.06–1.35), p = 0.0038). T2DM was related to mortality independent of age, sex, and CVRF regardless of LVH (hazard ratio (HR)T2DM-LVH 2.67 (95% CI 1.94–3.66), p < 0.0001; HRT2DM-noLVH 1.59 (95% CI 1.29–1.96), p < 0.0001), prediabetes was only associated with outcome in individuals with LVH independent of age and sex (HRprediabetes-LVH 1.51 (95% CI 1.01–2.25), p = 0.045). Neither T2DM nor prediabetes were predictors of incident LVH after adjustment for clinical covariates. Conclusions: Prediabetes and T2DM promote alterations of cardiac geometry. T2DM and particularly the coprevalence of T2DM with LVH substantially reduce life expectancy. These findings highlight the need for new therapeutic and screening approaches to prevent and detect cardiometabolic diseases at an early stage.

Sex-specific pattern of left ventricular hypertrophy and diastolic function in patients with type 2 diabetes mellitus

AIMS

Few prospective studies have evaluated sex-specific pattern, natural progression of left ventricular (LV) remodelling, and diastolic dysfunction in patients with type 2 diabetes (T2DM). The aim of this study was to study the sex-specific prevalence, longitudinal changes of LV remodelling, and diastolic dysfunction in patients with T2DM. Further, the prognostic value of diastolic function in women and men was also evaluated.

METHODS AND RESULTS

A total of 350 patients with T2DM (mean age 61 ± 11 years; women, 48.3%) was recruited. Detailed echocardiography was performed at baseline and after 25 months. A major adverse cardiovascular event (MACE) was defined as cardiovascular death, heart failure hospitalization, or myocardial infarction. Despite a similar age, prevalence of hypertension and body mass index, women had a higher prevalence of LV hypertrophy and diastolic dysfunction at baseline and follow-up compared with men. A total of 21 patients developed MACE (5 cardiovascular death, 9 hospitalization for heart failure, and 7 myocardial infarction) during a median follow-up of 56 months. Women with diastolic dysfunction had a higher incidence of MACE than those with normal diastolic function but this association was neutral in men. Multivariable Cox-regression analysis indicated that diastolic dysfunction was associated with MACE in women [hazard ratio = 6.30; 95% confidence interval (CI) = 1.06-37.54; P < 0.05] but not men (hazard ratio = 2.29, 95% CI = 0.67-7.89; P = 0.19).

CONCLUSION

LV hypertrophy and diastolic dysfunction, both at baseline and follow-up, were more common in women than men. Pre-clinical diastolic dysfunction was independently associated with MACE only in women with T2DM but was neutral in men.

The Diabetic Cardiomyopathy: The Contributing Pathophysiological Mechanisms

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

Natural and synthetic antioxidants targeting cardiac oxidative stress and redox signaling in cardiometabolic diseases

Cardiometabolic diseases (CMDs) are metabolic diseases (e.g., obesity, diabetes, atherosclerosis, rare genetic metabolic diseases, etc.) associated with cardiac pathologies. Pathophysiology of most CMDs involves increased production of reactive oxygen species and impaired antioxidant defense systems, resulting in cardiac oxidative stress (OxS). To alleviate OxS, various antioxidants have been investigated in several diseases with conflicting results. Here we review the effect of CMDs on cardiac redox homeostasis, the role of OxS in cardiac pathologies, as well as experimental and clinical data on the therapeutic potential of natural antioxidants (including resveratrol, quercetin, curcumin, vitamins A, C, and E, coenzyme Q10, etc.), synthetic antioxidants (including N-acetylcysteine, SOD mimetics, mitoTEMPO, SkQ1, etc.), and promoters of antioxidant enzymes in CMDs. As no antioxidant indicated for the prevention and/or treatment of CMDs has reached the market despite the large number of preclinical and clinical studies, a sizeable translational gap is evident in this field. Thus, we also highlight potential underlying factors that may contribute to the failure of translation of antioxidant therapies in CMDs.

Effect of Musk Tongxin Dropping Pill on Myocardial Remodeling and Microcirculation Dysfunction in Diabetic Cardiomyopathy

Objective

To explore the effect of Musk Tongxin Dropping Pill (MTDP) on myocardial remodeling and microcirculation dysfunction in diabetic cardiomyopathy (DCM).

Methods

Forty male SD rats were randomly divided into control group (control group, n = 10), DCM model group (DCM group, n = 10), DCM model + pioglitazone group (DCM + PLZ group, n = 10), and DCM model + MTDP group (DCM + MTDP group, n = 10). An intraperitoneal single injection of 65 mg/kg streptozotocin (STZ) was used to establish rat model of DCM and the rats in control group were treated with the same dose of sodium citrate buffer solution. DCM + PLZ group was treated with 3 mg/kg/d PLZ by ig after modeling, DCM + MTDP group was treated with 22 mg/kg/d MTDP by ig, and DCM group was treated with 2 ml/kg/d sodium carboxymethyl cellulose (CMC-Na) by ig. The general condition of rats was continuously observed. After intervening for 3 weeks, the random blood glucose of rats was detected by tail vein, and the echocardiography examination was performed. Blood specimens were collected from the abdominal aorta, serum nitric oxide (NO) and endothelin-1 (ET-1) were detected to estimate endothelial function, and tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), IL-1β, malondialdehyde (MDA), and superoxide dismutase (SOD) were detected to observe the changes of inflammation and oxidative stress indexes. The heart mass index (HMI) was calculated through the ratio of heart mass (HM) to the corresponding body mass (BM). Myocardial pathological tissue staining was performed.

Results

Compared with control group, blood glucose in other three groups was higher. Left ventricular end systolic diameter (LVSD) and left ventricular end diastolic diameter (LVDD) in DCM group showed a significant increase, while left ventricular ejection fraction (LVEF) and heart rate (HR) in this group displayed an obvious decrease (P < 0.01). BM and HM in DCM group exhibited a reduction, and HM/BM × 10³ revealed an apparent increase (P < 0.01). The levels of serum NO and SOD were distinctly downregulated (P < 0.01), and the levels of ET-1, MDA, TNF-α, IL-1β, and IL-6 were remarkably upregulated (P < 0.01). Compared with DCM group, a significant decrease was observed in LVSD and LVDD in DCM + MTDP group, while LVEF and HR obviously increased (P < 0.05). BM and HM indicated an apparent increase, but HM/BM ×10³ reduced distinctly (P < 0.01). The levels of serum NO and SOD were markedly upregulated (P < 0.05), and the levels of ET-1, MDA, TNF-α, IL-1β, and IL-6 were significantly downregulated (P < 0.05). HE staining showed that myocardial cells arranged neatly in the control group but not in the DCM group. The intercellular space between myocardial cells in DCM group increased, accompanied by damage of myocardial fibers and infiltration of inflammatory cells. Masson staining displayed an increase in interstitial collagen fibers in DCM group. Carstairs staining showed that microembolization occurred in the myocardium in DCM group, while in DCM + MTDP and DCM + PLZ groups the corresponding myocardial pathological changes were significantly improved.

Conclusions

MTDP might show a positive effect on myocardial remodeling and microcirculation dysfunction in DCM rats.

A Comprehensive miRNome Analysis of Macrophages Isolated from db/db Mice and Selected miRNAs Involved in Metabolic Syndrome-Associated Cardiac Remodeling

Cardiac macrophages are known from various activities, therefore we presume that microRNAs (miRNAs) produced or released by macrophages in cardiac tissue have impact on myocardial remodeling in individuals with metabolic syndrome (MetS). We aim to assess the cardiac macrophage miRNA profile by selecting those miRNA molecules that potentially exhibit regulatory functions in MetS-related cardiac remodeling. Cardiac tissue macrophages from control and db/db mice (an animal model of MetS) were counted and sorted with flow cytometry, which yielded two populations: CD45+CD11b+CD64+Ly6Chi and CD45+CD11b+CD64+Ly6Clow. Total RNA was then isolated, and miRNA expression profiles were evaluated with Next Generation Sequencing. We successfully sequenced 1400 miRNAs in both macrophage populations: CD45+CD11b+CD64+Ly6Chi and CD45+CD11b+CD64+Ly6Clow. Among the 1400 miRNAs, about 150 showed different expression levels in control and db/db mice and between these two subpopulations. At least 15 miRNAs are possibly associated with MetS pathology in cardiac tissue due to direct or indirect regulation of the expression of miRNAs for proteins involved in angiogenesis, fibrosis, or inflammation. In this paper, for the first time we describe the miRNA transcription profile in two distinct macrophage populations in MetS-affected cardiac tissue. Although the results are preliminary, the presented data provide a foundation for further studies on intercellular cross-talk/molecular mechanism(s) involved in the regulation of MetS-related cardiac remodeling.

lncRNA‑MALAT1 promotes high glucose‑induced H9C2 cardiomyocyte pyroptosis by downregulating miR‑141‑3p expression

Diabetic cardiomyopathy (DCM) is caused by diabetes and can result in heart failure. Long non-coding RNAs (lncRNAs) have been demonstrated to be closely associated with DCM development. The present study aimed to investigate whether lncRNA-metastasis-associated lung adenocarcinoma transcript-1 (MALAT1) altered high glucose (HG)-induced H9C2 cardiomyocyte pyroptosis by targeting microRNA (miR)-141-3p. H9C2 cells were treated with normal glucose (NG) or HG. lncRNA-MALAT1 and miR-141-3p expression levels were determined via reverse transcription-quantitative PCR (RT-qPCR). MALAT1 and miR-141-3p knockdown and overexpression were established and confirmed via RT-qPCR. The association between MALAT1 expression and miR-141-3p expression, as well as the induction of pyroptosis and gasdermin D (GSDMD)-N expression were evaluated by performing dual luciferase reporter, TUNEL staining and immunofluorescence staining assays, respectively. Western blotting was conducted to measure the expression levels of pyroptosis-associated proteins, including apoptosis-associated speck-like protein, GSDMD-N, caspase-1, nucleotide oligomerization domain-like receptor protein 3 and GSDMD. MALAT1 mRNA expression levels were significantly increased, whereas miR-141-3p expression levels were significantly decreased in HG-treated H9C2 cells compared with the NG group. Compared with the HG group, MALAT1 overexpression significantly reduced miR-141-3p expression levels, increased the rate of TUNEL positive cells and upregulated the expression levels of pyroptosis-associated proteins. MALAT1 knockdown displayed the opposite effect on the rate of TUNEL positive cells and the expression levels of pyroptosis-associated proteins. Furthermore, the rate of TUNEL positive cells, and GSDMD-N and pyroptosis-associated protein expression levels were significantly reduced by miR-141-3p overexpression in MALAT1-overexpression H9C2 cells. The results indicated that compared with NG treatment, HG treatment increased MALAT1 expression levels and decreased miR-141-3p expression levels in H9C2 cells. Therefore, the present study suggested that lncRNA-MALAT1 targeted miR-141-3p to promote HG-induced H9C2 cardiomyocyte pyroptosis.

TRPV4 Mediates Cardiac Fibrosis via the TGF-β1/Smad3 Signaling Pathway in Diabetic Rats

Emerging evidence shows that the transient receptor potential vanilloid 4 (TRPV4) channel is involved in fibrosis in many organs. However, its role in diabetic cardiac fibrosis remains unclear. Our aim was to evaluate the expression level of TRPV4 in the diabetic heart and clarify its role in diabetes-induced cardiac fibrosis. A diabetic animal model was induced by a single intraperitoneal injection of streptozotocin into Sprague-Dawley rats. We also investigated cardiac fibroblasts isolated from neonatal Sprague-Dawley rats. TRPV4 expression was significantly upregulated in both diabetic myocardium and cardiac fibroblasts cultured in high-glucose medium. Masson's trichrome staining revealed that the TRPV4 antagonist HC067047 attenuated the diabetes-induced cardiac fibrosis. Furthermore, HC067047 reduced collagen Ι synthesis and suppressed the transforming growth factor beta 1 (TGF-β1) level as well as the phosphorylation of Smad3 in the diabetic heart. In addition, the TRPV4 antagonist inhibited the proliferation of cardiac fibroblasts, collagen Ι synthesis, and activation of the TGF-β1/Smad3 signaling pathway induced by high-glucose culture medium. Our findings demonstrate that the upregulation of TRPV4 expression mediates diabetic cardiac fibrosis via activation of the TGF-β1/Smad3 signaling pathway.

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

CONTEXT

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

EVIDENCE ACQUISITION

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

EVIDENCE SYNTHESIS

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

CONCLUSIONS

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

Role of Non-coding RNA in Diabetic Cardiomyopathy

Diabetic cardiomyopathy (DCM) is the leading cause of morbidity and mortality in diabetic population worldwide, characteristic by cardiomyocyte hypertrophy, apoptosis and myocardial interstitial fibrosis and eventually developing into heart failure. Non-coding RNAs, such as microRNAs (miRNAs), circular RNAs (circRNAs), long non-coding RNAs (lncRNAs) and other RNAs without the protein encoding function were emerging as a popular regulator in various types of processes during human diseases. The evidences have shown that miRNAs are regulators in diabetic cardiomyopathy, such as insulin resistance, cardiomyocytes apoptosis, and inflammatory, especially their protective effect on heart function. Besides that, the functions of lncRNAs and circRNAs have been gradually confirmed in recent years, and their functions in DCM have become increasingly prominent. We highlighted the nonnegligible roles of non-coding RNAs in the pathological process of DCM and showed the future possibilities of these non-coding RNAs in DCM treatment. In this chapter, we summarized the present advance of the researches in this filed and raised the concern and the prospect in the future.

Role of Oxidative Stress in Metabolic and Subcellular Abnormalities in Diabetic Cardiomyopathy

Although the presence of cardiac dysfunction and cardiomyopathy in chronic diabetes has been recognized, the pathophysiology of diabetes-induced metabolic and subcellular changes as well as the therapeutic approaches for the prevention of diabetic cardiomyopathy are not fully understood. Cardiac dysfunction in chronic diabetes has been shown to be associated with Ca²⁺-handling abnormalities, increase in the availability of intracellular free Ca²⁺ and impaired sensitivity of myofibrils to Ca²⁺. Metabolic derangements, including depressed high-energy phosphate stores due to insulin deficiency or insulin resistance, as well as hormone imbalance and ultrastructural alterations, are also known to occur in the diabetic heart. It is pointed out that the activation of the sympathetic nervous system and renin-angiotensin system generates oxidative stress, which produces defects in subcellular organelles including sarcolemma, sarcoplasmic reticulum and myofibrils. Such subcellular remodeling plays a critical role in the pathogenesis of diabetic cardiomyopathy. In fact, blockade of the effects of neurohormonal systems has been observed to attenuate oxidative stress and occurrence of subcellular remodeling as well as metabolic abnormalities in the diabetic heart. This review is intended to describe some of the subcellular and metabolic changes that result in cardiac dysfunction in chronic diabetes. In addition, the therapeutic values of some pharmacological, metabolic and antioxidant interventions will be discussed. It is proposed that a combination therapy employing some metabolic agents or antioxidants with insulin may constitute an efficacious approach for the prevention of diabetic cardiomyopathy.

Advanced glycation end products facilitate the proliferation and reduce early apoptosis of cardiac microvascular endothelial cells via PKCβ signaling pathway: Insight from diabetic cardiomyopathy

Objective:

To investigate the effects of advanced glycation end products (AGEs) on the proliferation and apoptosis of cardiac microvascular endothelial cells (CMECs) in rats and their underlying signaling pathway.

Methods:

CMECs were isolated from Sprague–Dawley rats. We first examined the effects of AGEs on the proliferation and apoptosis of CMECs and then tested whether protein kinase C (PKC) β blockers could counteract the effects of AGEs. The PKC agonists phorbol 12-myristate 13-acetate (PMA) and PKCβ blockers were also used to verify whether PKC could act independently on CMECs. The receptor for AGEs (RAGE)–small interfering RNA (siRNA) transfection was used to verify the effect of AGEs on PKC. Following the above steps, we explained whether AGEs regulated the CMEC proliferation and early apoptosis through the PKCβ signaling pathway. Proliferation of CMECs was detected using the Cell Counting Kit-8 (CCK-8) assay, and early apoptosis was determined using the Annexin V- Fluorescein Isothiocyanate (FITC)/propidium iodide (PI) double staining. Expression of proliferation and apoptosis-related proteins and PKC phosphorylation were determined by western blotting analysis. Cell cycle distributions were assayed using a BD FACSCalibur cell-sorting system.

Results:

AGEs facilitated the proliferation of CMECs, upregulated phosphorylated extracellular signal regulated kinase (p-ERK), and accelerated the entry of cells from G1 phase to the S+G2/M phase, which was consistent with the upregulated cyclin D1 by AGEs. AGEs inhibited early apoptosis of CMECs by increasing the expression of survivin and decreasing the expression of cleaved-caspase3. All these effects can be reversed by PKCβ1/2inhibitors. In addition, AGE upregulated the RAGE expression and phosphorylation of PKCβ1/2 in CMECs, while the inhibition of RAGE reversed the phosphorylation, as well as the effects of AGEs on proliferation and apoptosis in CMECs.

Conclusion:

The study indicated that AGEs facilitated the proliferation and reduced early apoptosis of CMECs via the PKCβ signaling pathway.

Involvement of Heparanase in Endothelial Cell-Cardiomyocyte Crosstalk

Traditionally, the management of diabetes has focused mainly on controlling high blood glucose levels. Unfortunately, despite valiant efforts to normalize this blood glucose, poor medication management predisposes these patients to heart failure. Following diabetes, how the heart utilizes different sources of fuel for energy is key to the development of heart failure. The diabetic heart switches from using both glucose and fats, to predominately using fats as an energy resource for maintaining its activities. This transformation to using fats as an exclusive source of energy is helpful in the initial stages of the disease and is tightly controlled. However, over the progression of diabetes, there is a loss of this controlled supply and use of fats, which ultimately has terrible consequences since the uncontrolled use of fats produces toxic by-products which weaken heart function and cause heart disease. Heparanase is a key player that directs how much fats are provided to the heart and does so in association with several partners like LPL and VEGFs. Together, they regulate the amount of fats supplied, and their subsequent breakdown to provide energy. Following diabetes, there is a disruption in this network resulting in fat oversupply and cell death. Understanding how the heparanase-LPL-VEGFs "ensemble" cooperates, and its dysfunction in the diabetic heart would be useful in restoring metabolic equilibrium and limiting diabetes-related cardiac damage.

Dietary EPA Increases Rat Mortality in Diabetes Mellitus, A Phenomenon Which Is Compensated by Green Tea Extract

Diabetes is characterized by a high mortality rate which is often associated with heart failure. Green tea and eicosapentaenoic acid (EPA) are known to lessen some of the harmful impacts of diabetes and to exert cardio-protection. The aim of the study was to determine the effects of EPA, green tea extract (GTE), and a combination of both on the cardiac consequences of diabetes mellitus, induced in Wistar rats by injection of a low dose of streptozotocin (33 mg/kg) combined with a high fat diet. Cardiac mechanical function, coronary reactivity, and parameters of oxidative stress, inflammation, and energy metabolism were evaluated. In the context of diabetes, GTE alone limited several diabetes-related symptoms such as inflammation. It also slightly improved coronary reactivity and considerably enhanced lipid metabolism. EPA alone caused the rapid death of the animals, but this effect was negated by the addition of GTE in the diet. EPA and GTE combined enhanced coronary reactivity considerably more than GTE alone. In a context of significant oxidative stress such as during diabetes mellitus, EPA enrichment constitutes a risk factor for animal survival. It is essential to associate it with the antioxidants contained in GTE in order to decrease mortality rate and preserve cardiac function.

Impairment of the Akt pathway in transplanted Type 1 diabetic hearts is associated with post-transplant graft injury

OBJECTIVES

The use of 'marginal' hearts, such as from donors with diabetes mellitus (DM), could offer an opportunity to expand the donor pool in cardiac transplantation. Previous studies have shown that the phosphatidylinositol-3-kinase (PI3K)/Akt pathway is altered after ischaemia/reperfusion injury in the diabetic myocardium. We hypothesized that DM-induced cardiac dysfunction in donors is further impaired after heart transplantation and that PI3K/Akt-pathway alterations may be one of the underlying pathomechanisms.

METHODS

In the donor rats, DM was induced with a single dose of streptozotocin. Non-diabetic rats only received citrate buffer. After 8 weeks, the donor left ventricular (LV) cardiac function was measured. Then, the hearts were heterotopically transplanted into non-diabetic recipients. We evaluated LV graft function 1.5 h after transplantation via a Millar catheter system at different LV volumes. Histological analyses were performed, and the expression of 84 genes involved in PI3K/Akt signalling was profiled.

RESULTS

DM was associated with significantly decreased LV contractility and impaired relaxation. After transplantation, in the DM group, the grafts' systolic function (LV systolic pressure 112 ± 31 vs 155 ± 60 mmHg; dP/dtmax 2676 ± 896 vs 3584 ± 1779 mmHg/s, P < 0.05) and diastolic function (dP/dtmin 924 ± 205 vs 1748 ± 512 mmHg/s, P < 0.05) were significantly reduced at an intraventricular volume of 170 µl. The expression of 10 genes involved in PI3K/Akt signalling, as well as the phosphorylated Akt/total Akt protein expression ratio, were significantly down-regulated in the diabetic heart after transplantation.

CONCLUSIONS

DM-induced cardiac dysfunction is further impaired after transplantation. Targeting the PI3K/Akt pathway may result in a functional amelioration of the a priori-diseased myocardia, which could increase the number of potential cardiac donors.

Impact of obesity on longitudinal changes to cardiac structure and function in patients with Type 2 diabetes mellitus

AIMS

Few prospective studies have evaluated the natural progression of left ventricular (LV) remodelling in patients with Type 2 diabetes mellitus (T2DM). The aim of this study was to evaluate the impact of obesity on longitudinal cardiac structural and functional changes in patients with T2DM.

METHODS AND RESULTS

This study comprised of 274 patients with T2DM (mean age, 62.2 ± 11.4 years; male, 51.5%). Echocardiographic parameters including LV geometry, systolic, and diastolic functions were measured at baseline and follow-up. The median follow-up was 24 months (from 12 months to 48 months). The entire cohort showed a significant increase in LV wall thickness, LV mass (LVM), and prevalence of concentric hypertrophy (19.6-27.3%). Further, systolic function and diastolic function had deteriorated at follow-up assessment. Multivariable adjusted linear regression demonstrated that baseline body mass index (BMI) predicted longitudinal change to LVM (β  = 0.29, P < 0.01) and LV ejection fraction (β  = -0.15, P < 0.05). Patients were divided into three groups according to their BMI: normal weight (BMI <23 kg/m2), overweight (BMI between 23 kg/m2 and 27.5 kg/m2), or obese (BMI ≥27.5 kg/m2). Importantly, obesity at baseline predicted a greater longitudinal increase in LVM and decrease in LV ejection fraction compared with overweight and normal weight patients.

CONCLUSION

Being obese at baseline was associated with greater longitudinal increase in LV mass and greater deterioration in LV systolic function.

Peli1 induction impairs cardiac microvascular endothelium through Hsp90 dissociation from IRE1α

Ameliorating cardiac microvascular injury is the most effective means to mitigate diabetes-induced cardiovascular complications. Inositol-requiring 1α (IRE1α), a sensor of endoplasmic reticulum stress, is activated by Toll like receptors (TLRs), and then promotes cardiac microvascular injury. Peli1 is a master regulator of TLRs and activates IRE1α. This study aims to investigate whether Peli1 in endothelial cells promotes diabetes-induced cardiac microvascular injury through activating IRE1α. Here we found that Peli1 was markedly up-regulated in cardiac endothelial cells of both diabetic mice and in AGEs-treated cardiac microvascular endothelial cells (CMECs). Peli1 deficiency in endothelial cells significantly alleviated diabetes-induced cardiac microvascular permeability, promoted microvascular regeneration, and suppressed apoptosis, accompanied by the attenuation of adverse cardiac remodeling. Furthermore, Peli1 deletion in CMECs ameliorated AGEs-induced damages in vitro. We identified heat shock protein 90 (Hsp90) as a potential binding partner for Peli1, and the Ring domain of Peli1 directly bound with Hsp90 to enhance IRE1α phosphorylation. Our study suggests that blocking Peli1 in endothelial cells may protect against diabetes-induced cardiac microvascular injury by restraining ER stress.

Heart failure in the patient with diabetes: Epidemiology, aetiology, prognosis, therapy and the effect of glucose-lowering medications

In people with type 2 diabetes the frequency of heart failure (HF) is increased and mortality from HF is higher than with non-diabetic HF. The increased frequency of HF is attributable to the cardiotoxic tetrad of ischaemic heart disease, left ventricular hypertrophy, diabetic cardiomyopathy and an extracellular volume expansion resistant to atrial natriuretic peptides. Activation of the renin-angiotensin-aldosterone system and sympathetic nervous systems results in cardiac remodelling, which worsens cardiac function. Reversal of remodelling can be achieved, and cardiac function improved in people with HF with reduced ejection fraction (HFrEF) by treatment with angiotensin-converting enzyme inhibitors and β-blockers. However, with HF with preserved ejection fraction (HFpEF), only therapy for the underlying risk factors helps. Blockers of mineralocorticoid receptors may be beneficial in both HFrEF and HFpEF. Glucose-lowering drugs can have a negative effect (insulin, sulphonylureas, dipeptidyl peptidase-4 inhibitors and thiazolidinediones), a neutral effect (α-glucosidase inhibitors and glucagon-like peptide-1 receptor agonists) or a positive effect (sodium-glucose co-transporter-2 inhibitors and metformin).

Role of catecholamines in the pathogenesis of diabetic cardiomyopathy 1

Although the sympathetic nervous system plays an important role in the regulation of cardiac function, the overactivation of the sympathetic nervous system under stressful conditions including diabetes has been shown to result in the excessive production of circulating catecholamines as well as an increase in the myocardial concentration of catecholamines. In this brief review, we provide some evidence to suggest that the oxidation products of catecholamines such as aminochrome and oxyradicals, lead to metabolic derangements, Ca²⁺-handling abnormalities, increase in the availability of intracellular free Ca²⁺, as well as activation of proteases and changes in myocardial gene expression. These alterations due to elevated levels of circulatory catecholamines are associated with oxidative stress, subcellular remodeling, and the development of cardiac dysfunction in chronic diabetes.

High-sensitivity cardiac troponin T and severity of cerebral white matter lesions in patients with acute ischemic stroke

INTRODUCTION

Cardiac troponin (hs-cTnT) is a sensitive marker of myocardial injury and has been linked to incident dementia. The underlying mechanism of that observation is still unknown. Given that severity of cerebral small vessel disease is a predictor of cognitive decline, we aimed to explore whether there is an association between hs-cTnT and severity of white matter lesions (WML) as a marker of cerebral small vessel disease in patients with ischemic stroke.

METHODS

We analyzed consecutive acute ischemic stroke patients admitted to Charité-University Hospital, Berlin from 2011 to 2013. Severity of WML was graded on 3T-MRI using the age-related white matter severity score (ARWMS). Patients with hs-cTnT elevation suggestive of acute coronary syndrome (ACS) were excluded (hs-cTnT > 52 ng/l or dynamic change of hs-cTnT > 50%, ESC guideline). We performed unadjusted and adjusted quantile regression models to assess the association between increased hs-cTnT (dichotomized at the 99th percentile, 14 ng/l) and severity of WML.

RESULTS

A total of 860 patients was analyzed (median age 73 years, 44.8% female, median ARWMS 6). Patients with elevated hs-cTnT had more extensive WML than those without (median ARWMS 8 vs. 5, adjusted beta for 50th percentile 1.12, 95% CI 0.41-1.84). The association between WML and hs-cTnT elevation was strongest in patients with severe WML (adjusted beta 1.77, 95% CI 0.26-3.27 for 80th WML percentile).

CONCLUSION

Elevated hs-cTnT levels were associated with extent of WML in acute stroke patients. Further studies are needed to assess whether hs-cTnT can be used to identify stroke patients at risk for cognitive decline.

Silencing of NOD2 protects against diabetic cardiomyopathy in a murine diabetes model

The aim of the present study was to investigate the role of the nucleotide‑binding oligomerization domain (NOD) 2 in high glucose (HG)‑induced myocardial apoptosis and fibrosis in mice. Mouse models of diabetes were induced by streptozotocin (STZ). NOD2 expression was knocked down by injection of lentivirus‑mediated short‑hairpin RNA. Alternatively, small interfering RNA‑NOD2 was transfected into cardiomyocytes and cardiac fibroblasts (CFs). A hemodynamic assay was used to assess the cardiac function in the mouse model. Hematoxylin and eosin, Masson and terminal deoxynucleotidyl transferase dUTP nick end labeling staining was performed to observe pathological changes and injury of myocardial tissue. The expression levels of NOD2, collagen I and III, and transforming growth factor‑β (TGF‑β) and apoptotic proteins were quantified by reverse transcription‑quantitative polymerase chain reaction and western blotting. NOD2 silencing ameliorated diabetes‑induced myocardial apoptosis and fibrosis in mice. NOD2, collagen I, collagen III, TGF‑β and pro‑apoptotic proteins were upregulated in the diabetic cardiomyopathy (DCM) model group, but interference of NOD2 suppressed these alterations in protein expression levels. NOD2 is upregulated in HG‑induced primary cardiomyocytes and CFs. Suppression of NOD2 attenuated HG‑induced cardiomyocyte apoptosis and proliferation of CFs. Overall, NOD2 silencing alleviated myocardial apoptosis and fibrosis in diabetic mice. The results of the present study demonstrated an understanding of the role of NOD2 in diabetes‑induced cardiomyopathy, which provides a novel target and therapies for the prevention and treatment of DCM.

The heart failure burden of type 2 diabetes mellitus-a review of pathophysiology and interventions

Diabetes and heart failure (HF) are both global epidemics with tremendous costs on society with increased rates of HF hospitalizations and worsened prognosis when co-existing, making it a significant "deadly duo." The evidence for pharmacological treatment of HF in patients with type 2 diabetes mellitus (T2DM) stems typically from either subgroup analyses of patients that were recruited to randomized controlled trials of HF interventions, usually in patients with reduced ejection fraction (EF), or from subgroup analyses of HF patients recruited to cardiovascular (CV) outcome trials (CVOT) of glucose lowering agents involving patients with T2DM. Studies in patients with HF with preserved EF are sparse. This review summarizes the literature on pathophysiology and interventions aiming to reduce the HF burden in T2DM and includes HF trials of ACEi, digoxin, β-blocker, ARB, If-blocker, MRA, and ARNI involving 38,600 patients, with or without prevalent diabetes, and CV outcome trials in T2DM involving 74,351 patients, with or without prevalent HF. In all HF trials, HF outcomes by prevalent diabetes were reported with an incremental risk of HF and death confessed by prevalent diabetes and a treatment effect similar to those without diabetes. All T2DM CVOTs reported on HF outcomes with heterogeneity between trials with two reporting benefits (empagliflozin and canagliflozin) and two reporting increased risk (saxagliptin, pioglitazone). In vulnerable T2DM patients with concomitant HF, guideline-recommended HF drugs are effective. When choosing glucose-lowering therapy, outcomes from available CVOTs should be considered.

Heart Failure With Preserved Ejection Fraction in Diabetes: Mechanisms and Management

Diabetes mellitus (DM) is a major cause of heart failure in the Western world, either secondary to coronary artery disease or from a distinct entity known as "diabetic cardiomyopathy." Furthermore, heart failure with preserved ejection fraction (HFpEF) is emerging as a significant clinical problem for patients with DM. Current clinical data suggest that between 30% and 40% of patients with HFpEF suffer from DM. The typical structural phenotype of the HFpEF heart consists of endothelial dysfunction, increased interstitial and perivascular fibrosis, cardiomyocyte stiffness, and hypertrophy along with advanced glycation end products deposition. There is a myriad of mechanisms that result in the phenotypical HFpEF heart including impaired cardiac metabolism and substrate utilization, altered insulin signalling leading to protein kinase C activation, advanced glycated end products deposition, prosclerotic cytokine activation (eg, transforming growth factor-β activation), along with impaired nitric oxide production from the endothelium. Moreover, recent investigations have focused on the role of endothelial-myocyte interactions. Despite intense research, current therapeutic strategies have had little effect on improving morbidity and mortality in patients with DM and HFpEF. Possible explanations for this include a limited understanding of the role that direct cell-cell communication or indirect cell-cell paracrine signalling plays in the pathogenesis of DM and HFpEF. Additionally, integrins remain another important mediator of signals from the extracellular matrix to cells within the failing heart and might play a significant role in cell-cell cross-talk. In this review we discuss the characteristics and mechanisms of DM and HFpEF to stimulate potential future research for patients with this common, and morbid condition.