Molecular and metabolic mechanisms of cardiac dysfunction in diabetes

Association between lactate dehydrogenase to albumin ratio and acute kidney injury in patients with sepsis: a retrospective cohort study

BACKGROUND

Serum lactate dehydrogenase to albumin ratio (LAR) is associated with poor outcomes in malignancy and pneumonia. However, there are few studies suggesting that LAR is associated with the occurrence of acute kidney injury (AKI) in patients with sepsis, which was investigated in this study.

METHODS

We conducted a retrospective cohort study based on the Medical Information Mart for Intensive Care (MIMIC)-IV database. The primary outcome was the occurrence of AKI within 2 days and 7 days. Multivariable logistic regression models were used to calculate odds ratios to validate the association between LAR and AKI, in-hospital mortality, RRT use, and recovery of renal function, respectively.

RESULTS

A total of 4010 participants were included in this study. The median age of the participants was 63.5 years and the median LAR was 10.5. After adjusting for confounding variables, patients in the highest LAR quartile had a higher risk of AKI than those in the lowest LAR quartile within 2 days and 7 days, with odds ratios of 1.37 (95% confidence interval [CI]: 1.23-1.52) and 1.95 (95% CI: 1.72-2.22), respectively. The adjusted odds of AKI within 2 and 7 days were 1.16 (95% CI: 1.12-1.20) and 1.29 (95% CI: 1.24-1.35) for each 1 unit increase in LAR(log2), respectively.

CONCLUSION

This study demonstrated that elevated LAR was associated with poor prognosis in patients with sepsis. The risk of AKI and in-hospital mortality increased, the need for RRT increased, and the chance of recovery of renal function decreased with the increase of LAR.

Lower left atrial function in young individuals with type 1 diabetes mellitus compared to healthy controls: an echocardiographic study

In adulthood, individuals with type 1 diabetes mellitus may develop a condition of heart failure with preserved ejection fraction. However, subclinical changes to the heart in diabetes are likely to occur prior to the clinical presentation. This cross-sectional study aimed to compare left atrial function by echocardiography between 43 individuals with type 1 diabetes and 43 healthy controls, aged 10-30 years. All participants underwent echocardiography and 2D speckle tracking measurements for left atrial phase function parameters. Physical capacity was assessed by exercise test on a bicycle. Results showed that participants with type 1 diabetes had significantly lower left atrial function parameters than healthy controls (p < 0.05). There was a significant negative correlation between HbA1c means and reservoir and conduit strain (p < 0.05) and individuals with BMI < 30 showed a lower left atrial stiffness (p < 0.05). Individuals with type 1 diabetes and a higher physical capacity did not differ from their healthy peers. Results indicate that lower HbA1c levels, BMI < 30 and a higher physical capacity are favourable in terms of left atrial function in children and young adults with type 1 diabetes mellitus. Left atrial strain by echocardiography might become a new important tool in assessing heart function in T1DM.

The role of exosomes and exosomal microRNA in diabetic cardiomyopathy

Diabetic cardiomyopathy, a formidable cardiovascular complication linked to diabetes, is witnessing a relentless surge in its incidence. Despite extensive research efforts, the primary pathogenic mechanisms underlying this condition remain elusive. Consequently, a critical research imperative lies in identifying a sensitive and dependable marker for early diagnosis and treatment, thereby mitigating the onset and progression of diabetic cardiomyopathy (DCM). Exosomes (EXOs), minute vesicles enclosed within bilayer lipid membranes, have emerged as a fascinating frontier in this quest, capable of transporting a diverse cargo that mirrors the physiological and pathological states of their parent cells. These exosomes play an active role in the intercellular communication network of the cardiovascular system. Within the realm of exosomes, MicroRNA (miRNA) stands as a pivotal molecular player, revealing its profound influence on the progression of DCM. This comprehensive review aims to offer an introductory exploration of exosome structure and function, followed by a detailed examination of the intricate role played by exosome-associated miRNA in diabetic cardiomyopathy. Our ultimate objective is to bolster our comprehension of DCM diagnosis and treatment strategies, thereby facilitating timely intervention and improved outcomes.

Subclinical right ventricular dysfunction in patients with asymptomatic type 2 diabetes mellitus: A cross-sectional study

BACKGROUND

Diabetic cardiomyopathy, which involves both the right and left ventricles, progresses from a preclinical stage to overt heart failure. Detection of this entity at a preclinical stage could be crucial in intervening to halt its progression to overt heart failure. There is a paucity of literature on subclinical RV dysfunction in diabetic patients, and it is even rarer in the Indian literature. Our study intended to study this clinical entity through an echocardiographic assessment of asymptomatic patients.

OBJECTIVES

This was a cross-sectional observational analytic study, comparing subclinical RV dysfunction in diabetic and non-diabetic subjects by using echocardiography as a primary objective, while the secondary objective of the study was to find out the correlation between RV dysfunction and the duration of diabetes mellitus and HbA1C levels.

METHODS

Conventional echocardiography with tissue Doppler imaging (TDI) was used to measure nine different echocardiographic parameters in the diabetic and non-diabetic groups. All probable causes of RV dysfunction were excluded before enrolling the patients in the study. Unpaired t-test was used to compare the parameters between the two groups, and multivariate regression analysis was done taking into consideration age, duration of diabetes, and HbA1C levels as the independent variables, and echocardiographic parameters as the dependent variables.

RESULTS

Out of the nine different echocardiographic parameters, Tricuspid annular plane systolic excursion (TAPSE), RV end diastolic diameter (RVEDD), Tricuspid peak late diastolic velocity (A), E/A ratio, RV basal segment peak myocardial systolic velocity (Sm), RV basal segment peak early diastolic velocity (Em), RV basal segment peak late diastolic velocity (Am), and E/Em ratio showed statistically significant differences between the two groups. These results show the presence of subclinical RV dysfunction in diabetic patients. TAPSE and E/A ratio showed a significant correlation with the duration of diabetes, while Em showed a significant correlation with HbA1C.

CONCLUSION

Diabetes mellitus is associated with subclinical systolic as well as diastolic RV dysfunction. In addition to helping identify people at high risk, the early recognition of RV dysfunction gives us a window of opportunity to take action and slow down the disease's course. This study emphasizes that the early identification of RV diastolic as well as systolic dysfunction in asymptomatic Type 2 diabetic patients can be a helpful tool in halting the progression of disease from subclinical to frank clinical cases, thereby preventing the morbidity and mortality associated with heart failure. Hence, it adds value to the pre-existing literature.

NAFLD: An Emerging Causal Factor for Cardiovascular Disease

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease worldwide that poses a significant threat to human health. Cardiovascular disease (CVD) is the leading cause of mortality in NAFLD patients. NAFLD and CVD share risk factors such as obesity, insulin resistance, and type 2 diabetes. However, whether NAFLD is a causal risk factor for CVD remains a matter of debate. This review summarizes the evidence from prospective clinical and Mendelian randomization studies that underscore the potential causal relationship between NAFLD and CVD. The mechanisms of NAFLD contributing to the development of CVD and the necessity of addressing CVD risk while managing NAFLD in clinical practice are also discussed.

Creatine Kinase Equilibration and ΔGATP over an Extended Range of Physiological Conditions: Implications for Cellular Energetics, Signaling, and Muscle Performance

In this report, we establish a straightforward method for estimating the equilibrium constant for the creatine kinase reaction (CK Keq″) over wide but physiologically and experimentally relevant ranges of pH, Mg2+ and temperature. Our empirical formula for CK Keq″ is based on experimental measurements. It can be used to estimate [ADP] when [ADP] is below the resolution of experimental measurements, a typical situation because [ADP] is on the order of micromolar concentrations in living cells and may be much lower in many in vitro experiments. Accurate prediction of [ADP] is essential for in vivo studies of cellular energetics and metabolism and for in vitro studies of ATP-dependent enzyme function under near-physiological conditions. With [ADP], we were able to obtain improved estimates of ΔGATP, necessitating the reinvestigation of previously reported ADP- and ΔGATP-dependent processes. Application to actomyosin force generation in muscle provides support for the hypothesis that, when [Pi] varies and pH is not altered, the maximum Ca2+-activated isometric force depends on ΔGATP in both living and permeabilized muscle preparations. Further analysis of the pH studies introduces a novel hypothesis around the role of submicromolar ADP in force generation.

Improvement of Left Ventricular Global Longitudinal Strain after 6-Month Therapy with GLP-1RAs Semaglutide and Dulaglutide in Type 2 Diabetes Mellitus: A Pilot Study

(1) Background: Glucagone-Like Peptide-1 Receptor Agonists (GLP-1 RAs) (GLP-1 RAs) are incretine-based medications recommended in the treatment of type 2 Diabetes Mellitus (DM2) with atherosclerotic cardiovascular disease (ASCVD) or high or very high cardiovascular (CV) risk. However, knowledge of the direct mechanism of GLP-1 RAs on cardiac function is modest and not yet fully elucidated. Left ventricular (LV) Global Longitudinal Strain (GLS) with Speckle Tracking Echocardiography (STE) represents an innovative technique for the evaluation of myocardial contractility. (2) Methods: an observational, perspective, monocentric study was conducted in a cohort of 22 consecutive patients with DM2 and ASCVD or high/very high CV risk, enrolled between December 2019 and March 2020 and treated with GLP-1 RAs dulaglutide or semaglutide. The echocardiographic parameters of diastolic and systolic function were recorded at baseline and after six months of treatment. (3) Results: the mean age of the sample was 65 ± 10 years with a prevalence of the male sex (64%). A significant improvement in the LV GLS (mean difference: -1.4 ± 1.1%; p value < 0.001) was observed after six months of treatment with GLP-1 RAs dulaglutide or semaglutide. No relevant changes were seen in the other echocardiographic parameters. (4) Conclusions: six months of treatment with GLP-1 RAs dulaglutide or semaglutide leads to an improvement in the LV GLS in subjects with DM2 with and high/very high risk for ASCVD or with ASCVD. Further studies on larger populations and with a longer follow-up are warranted to confirm these preliminary results.

Moderate-Intensity Exercise Maintains Redox Homeostasis for Cardiovascular Health

It is well known that exercise is beneficial for cardiovascular health. Oxidative stress is the common pathological basis of many cardiovascular diseases. The overproduction of free radicals, both reactive oxygen species and reactive nitrogen species, can lead to redox imbalance and exacerbate oxidative damage to the cardiovascular system. Maintaining redox homeostasis and enhancing anti-oxidative capacity are critical mechanisms by which exercise protects against cardiovascular diseases. Moderate-intensity exercise is an effective means to maintain cardiovascular redox homeostasis. Moderate-intensity exercise reduces the risk of cardiovascular disease by improving mitochondrial function and anti-oxidative capacity. It also attenuates adverse cardiac remodeling and enhances cardiac function. This paper reviews the primary mechanisms of moderate-intensity exercise-mediated redox homeostasis in the cardiovascular system. Exploring the role of exercise-mediated redox homeostasis in the cardiovascular system is of great significance to the prevention and treatment of cardiovascular diseases.

Independent effects of the triglyceride-glucose index on all-cause mortality in critically ill patients with coronary heart disease: analysis of the MIMIC-III database

BACKGROUND

The triglyceride-glucose (TyG) index is a reliable alternative biomarker of insulin resistance (IR). However, whether the TyG index has prognostic value in critically ill patients with coronary heart disease (CHD) remains unclear.

METHODS

Participants from the Medical Information Mart for Intensive Care III (MIMIC-III) were grouped into quartiles according to the TyG index. The primary outcome was in-hospital all-cause mortality. Cox proportional hazards models were constructed to examine the association between TyG index and all-cause mortality in critically ill patients with CHD. A restricted cubic splines model was used to examine the associations between the TyG index and outcomes.

RESULTS

A total of 1,618 patients (65.14% men) were included. The hospital mortality and intensive care unit (ICU) mortality rate were 9.64% and 7.60%, respectively. Multivariable Cox proportional hazards analyses indicated that the TyG index was independently associated with an elevated risk of hospital mortality (HR, 1.71 [95% CI 1.25-2.33] P = 0.001) and ICU mortality (HR, 1.50 [95% CI 1.07-2.10] P = 0.019). The restricted cubic splines regression model revealed that the risk of hospital mortality and ICU mortality increased linearly with increasing TyG index (P for non-linearity = 0.467 and P for non-linearity = 0.764).

CONCLUSIONS

The TyG index was a strong independent predictor of greater mortality in critically ill patients with CHD. Larger prospective studies are required to confirm these findings.

MORPHOLOGICAL CHARACTERISTICS OF THE ENDOCRINE FUNCTION OF THE HEART IN COMORBID PATHOLOGY

OBJECTIVE

Aim: To study the ultrastructural remodeling of atrial myoendocrine cells (AMC) of the atrial myocardium in streptozotocin-induced diabetes (SID) under chronic immobilization stress (CIS).

PATIENTS AND METHODS

Materials and methods: 40 sexually mature white male rats (body weight 150-180 g) were included in the study. Four groups were formed: group 1 - animals with comorbid pathology (SID and CIS), group 2 - animals with SID, group 3 - animals with CIS, group 4 - intact animals.

RESULTS

Results: On the 14th day of the development of SID and CIS, an increase in the functional activity of AMC is noted, which is confirmed by hyperplasia and hypertrophy of the protein-synthesizing apparatus, an increase in the volume density of secretory granules (SG), especially diffusing ones, and indicates enhanced release of atrial natriuretic peptide (ANP) from cells during the experiment. On the 56th day of the experiment, in groups 1 and 2 of , destructive changes in AMC were noted, such as vacuolar and balloon dystrophy, colliquative and partial necrosis. At the same time, the functional activity of AMC of different regions of the myocardium significantly. In animals with CIS, the volume density of young and diffusing SG in AMC is decreased.

CONCLUSION

Conclusions: Therefore, in the early stages of the development of SID and CIS, an increase in the morpho-functional activity of AMC is noted. The long course of SID and its combination with CIS lead to destructive changes in AMC and to decrease in their secretory activity.

Unveiling the Vital Role of Long Non-Coding RNAs in Cardiac Oxidative Stress, Cell Death, and Fibrosis in Diabetic Cardiomyopathy

Diabetes mellitus is a burdensome public health problem. Diabetic cardiomyopathy (DCM) is a major cause of mortality and morbidity in diabetes patients. The pathogenesis of DCM is multifactorial and involves metabolic abnormalities, the accumulation of advanced glycation end products, myocardial cell death, oxidative stress, inflammation, microangiopathy, and cardiac fibrosis. Evidence suggests that various types of cardiomyocyte death act simultaneously as terminal pathways in DCM. Long non-coding RNAs (lncRNAs) are a class of RNA transcripts with lengths greater than 200 nucleotides and no apparent coding potential. Emerging studies have shown the critical role of lncRNAs in the pathogenesis of DCM, along with the development of molecular biology technologies. Therefore, we summarize specific lncRNAs that mainly regulate multiple modes of cardiomyopathy death, oxidative stress, and cardiac fibrosis and provide valuable insights into diagnostic and therapeutic biomarkers and strategies for DCM.

Cardiac hypertrophy and fibrosis were attenuated by olive leaf extract treatment in a rat model of diabetes

The key role of fibrosis and hypertrophy processes in developing diabetes-induced heart injury has been demonstrated. Considering the known hypoglycemic effects of olive leaf extract (OLE), we decided to investigate its potential effect and associated mechanisms on cardiac fibrosis and myocardial hypertrophy in streptozotocin (STZ)-induced diabetic rats. Eight groups were included in this study: control, diabetic, diabetic-OLEs (100, 200 and 400 mg/kg), diabetic-metformin (300 mg/kg), diabetic-valsartan (30 mg/kg), and diabetic-metformin/valsartan (300/30 mg/kg). After a treatment period of 6 weeks, echocardiography was used to assess cardiac function. Heart-to-body weight ratio (HW/BW) and fasting blood sugar (FBS) were measured. Myocardial histology was examined by Masson's trichrome staining. Gene expressions of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), β-myosin heavy chain (β-MHC), TGF-β1, TGF-β3, angiotensin II type 1 receptor (AT1), alpha-smooth muscle actin (α-SMA), and collagen were evaluated by the quantitative real-time PCR in heart tissue. A reduction in the FBS level and HW/BW ratio in the extract groups was obvious. The improvement of left ventricular dysfunction, cardiac myocytes hypertrophy, and myocardial interstitial fibrosis was also observed in treated groups. A lowering trend in the expression of all hypertrophic and fibrotic indicator genes was evident in the myocardium of OLE treated rats. Our data indicated that OLE could attenuate fibrosis and reduce myocardial hypertrophy markers, thus improving the cardiac function and structure in the STZ-induced diabetic rats. PRACTICAL APPLICATIONS: This study demonstrates that olive leaf extract in addition to lowering blood glucose levels and the heart-to-body weight ratio (HW/BW) may also improve cardiac function and reduce cardiac hypertrophy and fibrosis in cardiac tissue, which leads to inhibition of diabetic heart damage. Thus it is possible that including olive leaf extracts in the diets of individuals with diabetes may assist in lowering cardiovascular disease risk factors.

Energy substrate metabolism and oxidative stress in metabolic cardiomyopathy

Metabolic cardiomyopathy is an emerging cause of heart failure in patients with obesity, insulin resistance, and diabetes. It is characterized by impaired myocardial metabolic flexibility, intramyocardial triglyceride accumulation, and lipotoxic damage in association with structural and functional alterations of the heart, unrelated to hypertension, coronary artery disease, and other cardiovascular diseases. Oxidative stress plays an important role in the development and progression of metabolic cardiomyopathy. Mitochondria are the most significant sources of reactive oxygen species (ROS) in cardiomyocytes. Disturbances in myocardial substrate metabolism induce mitochondrial adaptation and dysfunction, manifested as a mismatch between mitochondrial fatty acid oxidation and the electron transport chain (ETC) activity, which facilitates ROS production within the ETC components. In addition, non-ETC sources of mitochondrial ROS, such as β-oxidation of fatty acids, may also produce a considerable quantity of ROS in metabolic cardiomyopathy. Augmented ROS production in cardiomyocytes can induce a variety of effects, including the programming of myocardial energy substrate metabolism, modulation of metabolic inflammation, redox modification of ion channels and transporters, and cardiomyocyte apoptosis, ultimately leading to the structural and functional alterations of the heart. Based on the above mechanistic views, the present review summarizes the current understanding of the mechanisms underlying metabolic cardiomyopathy, focusing on the role of oxidative stress.

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

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

Cardiac magnetic resonance T1 mapping for evaluating myocardial fibrosis in patients with type 2 diabetes mellitus: correlation with left ventricular longitudinal diastolic dysfunction

OBJECTIVES

We aimed to evaluate myocardial fibrosis using cardiac magnetic resonance (CMR) T1 mapping in type 2 diabetes mellitus (T2DM) patients and investigate the association between left ventricular (LV) subclinical myocardial dysfunction and myocardial fibrosis.

METHODS

The study included 37 short-term (≤ 5 years) and 44 longer-term (> 5 years) T2DM patients and 41 healthy controls. The LV global strain parameters and T1 mapping parameters were compared between the abovementioned three groups. The association of T1 mapping parameters with diabetes duration, in addition to other risk factors, was determined using multivariate linear regression analysis. The correlation between LV strain parameters and T1 mapping parameters was evaluated using Pearson's correlation.

RESULTS

The peak diastolic strain rates (PDSRs) were significantly lower in longer-term T2DM patients compared to those in healthy subjects and short-term T2DM patients (p < 0.05). The longitudinal peak systolic strain rate and peak strain were significantly lower in the longer-term T2DM compared with the short-term T2DM group (p < 0.05). The extracellular volumes (ECVs) were higher in both subgroups of T2DM patients compared with control subjects (all p < 0.05). Multivariate linear regression analysis showed that diabetes duration was independently associated with ECV (β = 0.413, p < 0.001) by taking covariates into account. Pearson's analysis showed that ECV was associated with longitudinal PDSR (r = - 0.441, p < 0.001).

CONCLUSION

T1 mapping could detect abnormal myocardial fibrosis early in patients with T2DM, which can cause a decline in the LV diastolic function.

KEY POINTS

• CMR T1 mapping could detect abnormal myocardial fibrosis early in patients with T2DM. • The diabetes duration was independently associated with ECV. • Myocardial fibrosis can cause a decline in the LV diastolic function in T2DM patients.

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.

Cyclovirobuxine D Ameliorates Experimental Diabetic Cardiomyopathy by Inhibiting Cardiomyocyte Pyroptosis via NLRP3 in vivo and in vitro

Diabetic cardiomyopathy (DCM) is one of the common complications of diabetic patients, which can induce myocardial hypertrophy, cardiac fibrosis, and heart failure. Growing evidence has shown that the occurrence and development of DCM are accompanied by pyroptosis which is an NLRP3-mediated intense inflammatory cell death. Cyclovirobuxine D (CVB-D) has been shown to significantly ameliorate DCM and anti-inflammatory effects associated with cardiomyopathy, but it is unclear whether it has an effect on cardiomyocyte pyroptosis accompanying DCM. Therefore, the purpose of the present study was to explore the ameliorating effect of CVB-D on cardiomyocyte pyroptosis associated with DCM and its molecular regulation mechanism. Type 2 diabetes in C57BL/6 mice was reproduced by the high-fat and high-glucose diet (HFD) combined with low-dose streptozotocin (STZ). The characteristics of DCM were evaluated by cardiac ultrasonography, serum detection, and histopathological staining. The results suggested that CVB-D could significantly alleviate the cardiac pathology of DCM. Then, we explored the mechanism of CVB-D on primary neonatal rat cardiomyocyte (PNRCM) injury with high glucose (HG) in vitro to simulate the physiological environment of DCM. Preincubation with CVB-D could significantly increase cell viability, attenuate cytopathological changes and inhibit the expression levels of pyroptosis-related proteins. Further research found that the myocardial improvement effect of CVB-D was related to its inhibition of NLRP3 expression. In conclusion, our data suggest that CVB-D can ameliorate DCM by inhibiting cardiomyocyte pyroptosis via NLRP3, providing a novel molecular target for CVB-D clinical application.

Role of cannabinoids and the endocannabinoid system in modulation of diabetic cardiomyopathy

Diabetic complications, chiefly seen in long-term situations, are persistently deleterious to a large extent, requiring multi-factorial risk reduction strategies beyond glycemic control. Diabetic cardiomyopathy is one of the most common deleterious diabetic complications, being the leading cause of mortality among diabetic patients. The mechanisms of diabetic cardiomyopathy are multi-factorial, involving increased oxidative stress, accumulation of advanced glycation end products (AGEs), activation of various pro-inflammatory and cell death signaling pathways, and changes in the composition of extracellular matrix with enhanced cardiac fibrosis. The novel lipid signaling system, the endocannabinoid system, has been implicated in the pathogenesis of diabetes and its complications through its two main receptors: Cannabinoid receptor type 1 and cannabinoid receptor type 2, alongside other components. However, the role of the endocannabinoid system in diabetic cardiomyopathy has not been fully investigated. This review aims to elucidate the possible mechanisms through which cannabinoids and the endocannabinoid system could interact with the pathogenesis and the development of diabetic cardiomyopathy. These mechanisms include oxidative/ nitrative stress, inflammation, accumulation of AGEs, cardiac remodeling, and autophagy. A better understanding of the role of cannabinoids and the endocannabinoid system in diabetic cardiomyopathy may provide novel strategies to manipulate such a serious diabetic complication.

Cannabinoid receptor 2 activation alleviates diabetes-induced cardiac dysfunction, inflammation, oxidative stress, and fibrosis

Diabetes mellitus promotes accelerated cardiovascular aging and inflammation, which in turn facilitate the development of cardiomyopathy/heart failure. High glucose-induced oxidative/nitrative stress, activation of various pro-inflammatory, and cell death pathways are critical in the initiation and progression of the changes culminating in diabetic cardiomyopathy. Cannabinoid 2 receptor (CB₂R) activation in inflammatory cells and activated endothelium attenuates the pathological changes associated with atherosclerosis, myocardial infarction, stroke, and hepatic cardiomyopathy. In this study, we explored the role of CB₂R signaling in myocardial dysfunction, oxidative/nitrative stress, inflammation, cell death, remodeling, and fibrosis associated with diabetic cardiomyopathy in type 1 diabetic mice. Control human heart left ventricles and atrial appendages, similarly to mouse hearts, had negligible CB₂R expression determine by RNA sequencing or real-time RT-PCR. Diabetic cardiomyopathy was characterized by impaired diastolic and systolic cardiac function, enhanced myocardial CB₂R expression, oxidative/nitrative stress, and pro-inflammatory response (tumor necrosis factor-α, interleukin-1β, intracellular adhesion molecule 1, macrophage inflammatory protein-1, monocyte chemoattractant protein-1), macrophage infiltration, fibrosis, and cell death. Pharmacological activation of CB₂R with a selective agonist attenuated diabetes-induced inflammation, oxidative/nitrative stress, fibrosis and cell demise, and consequent cardiac dysfunction without affecting hyperglycemia. In contrast, genetic deletion of CB₂R aggravated myocardial pathology. Thus, selective activation of CB₂R ameliorates diabetes-induced myocardial tissue injury and preserves the functional contractile capacity of the myocardium in the diabetic milieu. This is particularly encouraging, since unlike CB₁R agonists, CB₂R agonists do not elicit psychoactive activity and cardiovascular side effects and are potential clinical candidates in the treatment of diabetic cardiovascular and other complications.

Attenuation of ROS/Chloride Efflux-Mediated NLRP3 Inflammasome Activation Contributes to Alleviation of Diabetic Cardiomyopathy in Rats after Sleeve Gastrectomy

Diabetic cardiomyopathy (DCM) can develop in diabetes mellitus and is a major cause of morbidity and mortality. Surgical bariatric surgery procedures, such as sleeve gastrectomy (SG), result in remission of type 2 diabetes and have benefits regarding systolic and diastolic myocardial function. The NLR family pyrin domain containing 3 (NLRP3) inflammasome appears to participate in the development of DCM. However, whether SG surgery affects myocardial NLRP3 inflammasome-related pyroptosis to improve cardiac function remains unclear. This study was aimed at investigating the effect of SG surgery on NLRP3-associated pyroptosis in rats with DCM. We also examined cellular phenotypes and molecular mechanisms in high glucose-stimulated myocytes. The rat model of DCM was established by high-fat diet feeding and low-dose streptozotocin injection. We observed a metabolic benefit of SG, including a reduced body weight, food intake, and blood glucose levels and restored glucose tolerance and insulin sensitivity postoperatively. We observed a marked decline in glucose uptake in rats with DCM, and this was restored after SG. Also, SG alleviated the dysfunction of myocardial contraction and diastole, delayed the progression of DCM, and reduced the NLRP3 inflammasome-mediated myocardial pyroptosis in vivo. H9c2 cardiomyocytes showed membrane disruption and DNA damage under a high glucose stimulus, which suggested myocardial pyroptosis. Using a ROS scavenger or chloride channel blocker in vitro restored myocardial NLRP3-mediated pyroptosis. Furthermore, we found that chloride efflux acted downstream of ROS generation. In conclusion, SG may ameliorate or even reverse the progression of DCM. Our study provides evidence that the SG operation alleviates NLRP3 inflammasome dysregulation in DCM. Clearance of ROS overburden and suppression of chloride efflux due to SG might act as the proximal event before inhibition of NLRP3 inflammasome in the myocardium, thus contributing to morphological and functional alleviation of DCM.

Differentially expressed tRNA-derived fragments and their roles in primary cardiomyocytes stimulated by high glucose

Diabetic cardiomyopathy (DCM) is a serious complication of diabetes mellitus that can cause malignant arrhythmia and sudden death and is associated with cardiomyocyte dysfunction induced by hyperglycemia. Emerging evidence has revealed that transfer RNA-derived fragments (tRFs), a novel class of noncoding RNAs, play a crucial role in a variety of pathophysiologic processes, including cell death, cell growth and proliferation. However, it remains unknown whether and how tRFs are involved in cardiomyocyte dysfunction during the progression of DCM. In this study, we found that cardiomyocyte abnormalities were induced by high glucose (HG) treatment, as demonstrated by a decrease in cell viability and autophagy activation as well as an increase in cell death and proinflammatory cytokine release. Moreover, HG treatment resulted in differential expression of tRFs in cardiomyocytes, of which 4 upregulated and 1 downregulated tRFs were observed compared with the control group. The differential expression of 4 upregulated tRFs was primarily involved in cardiac dysfunction-related processes, such as autophagy, AGE-RAGE signaling pathway in diabetic complications, MAPK signaling pathway, insulin signaling pathway, FoxO signaling pathway, insulin resistance and peroxisome pathways based on Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Furthermore, we found that tRF-5014a, the most significantly upregulated tRF among all tested tRFs, negatively regulated the expression of the autophagy-related protein ATG5. Importantly, inhibition of tRF-5014a not only abolished autophagy inactivation but also attenuated the decrease in cell viability and increase in cell death as well as proinflammatory cytokine release under HG conditions. These findings suggest that tRFs may contribute to HG-induced cardiomyocyte injury during DCM progression.

Hydrogen sulfide plays a potential alternative for the treatment of metabolic disorders of diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) is a cardiovascular complication that tends to occur in patients with diabetes, obesity, or insulin resistance, with a higher late mortality rate. Sustained hyperglycemia, increased free fatty acids, or insulin resistance induces metabolic disorders in cardiac tissues and cells, leading to myocardial fibrosis, left ventricular hypertrophy, diastolic and/or systolic dysfunction, and finally develop into congestive heart failure. The close connection between all signaling pathways and the complex pathogenesis of DCM cause difficulties in finding effective targets for the treatment of DCM. It reported that hydrogen sulfide (H₂S) could regulate cell energy substrate metabolism, reduce insulin resistance, protect cardiomyocytes, and improve myocardial function by acting on related key proteins such as differentiation cluster 36 (CD36) and glucose transporter 4 (GLUT4). In this article, the relative mechanisms of H₂S in alleviating metabolic disorders of DCM were reviewed, and how H₂S can better prevent and treat DCM in clinical practice will be discussed.

Inflammation in Metabolic Cardiomyopathy

Overlapping pandemics of lifestyle-related diseases pose a substantial threat to cardiovascular health. Apart from coronary artery disease, metabolic disturbances linked to obesity, insulin resistance and diabetes directly compromise myocardial structure and function through independent and shared mechanisms heavily involving inflammatory signals. Accumulating evidence indicates that metabolic dysregulation causes systemic inflammation, which in turn aggravates cardiovascular disease. Indeed, elevated systemic levels of pro-inflammatory cytokines and metabolic substrates induce an inflammatory state in different cardiac cells and lead to subcellular alterations thereby promoting maladaptive myocardial remodeling. At the cellular level, inflammation-induced oxidative stress, mitochondrial dysfunction, impaired calcium handling, and lipotoxicity contribute to cardiomyocyte hypertrophy and dysfunction, extracellular matrix accumulation and microvascular disease. In cardiometabolic patients, myocardial inflammation is maintained by innate immune cell activation mediated by pattern recognition receptors such as Toll-like receptor 4 (TLR4) and downstream activation of the NLRP3 inflammasome and NF-κB-dependent pathways. Chronic low-grade inflammation progressively alters metabolic processes in the heart, leading to a metabolic cardiomyopathy (MC) phenotype and eventually to heart failure with preserved ejection fraction (HFpEF). In accordance with preclinical data, observational studies consistently showed increased inflammatory markers and cardiometabolic features in patients with HFpEF. Future treatment approaches of MC may target inflammatory mediators as they are closely intertwined with cardiac nutrient metabolism. Here, we review current evidence on inflammatory processes involved in the development of MC and provide an overview of nutrient and cytokine-driven pro-inflammatory effects stratified by cell type.

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.

Effects of Bergamot Polyphenols on Mitochondrial Dysfunction and Sarcoplasmic Reticulum Stress in Diabetic Cardiomyopathy

Cardiovascular disease is the leading cause of death and disability in the Western world. In order to safeguard the structure and the functionality of the myocardium, it is extremely important to adequately support the cardiomyocytes. Two cellular organelles of cardiomyocytes are essential for cell survival and to ensure proper functioning of the myocardium: mitochondria and the sarcoplasmic reticulum. Mitochondria are responsible for the energy metabolism of the myocardium, and regulate the processes that can lead to cell death. The sarcoplasmic reticulum preserves the physiological concentration of the calcium ion, and triggers processes to protect the structural and functional integrity of the proteins. The alterations of these organelles can damage myocardial functioning. A proper nutritional balance regarding the intake of macronutrients and micronutrients leads to a significant improvement in the symptoms and consequences of heart disease. In particular, the Mediterranean diet, characterized by a high consumption of plant-based foods, small quantities of red meat, and high quantities of olive oil, reduces and improves the pathological condition of patients with heart failure. In addition, nutritional support and nutraceutical supplementation in patients who develop heart failure can contribute to the protection of the failing myocardium. Since polyphenols have numerous beneficial properties, including anti-inflammatory and antioxidant properties, this review gathers what is known about the beneficial effects of polyphenol-rich bergamot fruit on the cardiovascular system. In particular, the role of bergamot polyphenols in mitochondrial and sarcoplasmic dysfunctions in diabetic cardiomyopathy is reported.

The parp-1 and bax genes as potential targets for treatment of the heart functioning impairments induced by type 1 diabetes mellitus

Objectives. The present study was designed to assess whether apoptosis-related genes as parp-1 and bax could be targets for treatment of diabetes mellitus and whether vitamin D may exert beneficial effects. Methods. Vitamin D₃ treatment for 4 weeks, starting after 4 weeks of the diabetes duration. The expression of parp-1 and bax genes was estimated on mRNA levels using real time quantitative polymerase chain reaction. Results. After 8 weeks, diabetic rats had weight loss, while blood glucose was increased about 4.9-fold compared to control group. Vitamin D₃ administration to diabetic animals had no effect on these parameters. It was found that total serum alkaline phosphatase activity was significantly elevated in diabetic rats as compared to control animals and was restored by vitamin D₃. Diabetes was accompanied by reduction of nicotinamidadenindinucleotide, a substrate of poly-ADP-ribosylation, level by 31.7% as compared to control rats, which was not reversed in response to vitamin D₃ treatment. In diabetic hearts, the mRNA expression level of parp-1 gene was 2.8-fold higher compared to control rats and partially decreased by vitamin D3 treatment. Less significant alterations were observed in diabetic hearts for the mRNA expression level of bax gene that was 2.0-fold higher compared to control animals and vitamin D₃ normalized it. These results indicate that cardiomyocytes have a tendency to apoptosis. Conclusions. The findings suggest that investigated genes can be targets at the transcriptional level for vitamin D action that may be contributed to the improving metabolic/signaling pathways induced by diabetes mellitus.

Modeling different types of diabetes using human pluripotent stem cells

Diabetes mellitus (DM) is a metabolic disease characterized by chronic hyperglycemia as a result of progressive loss of pancreatic β cells, which could lead to several debilitating complications. Different paths, triggered by several genetic and environmental factors, lead to the loss of pancreatic β cells and/or function. Understanding these many paths to β cell damage or dysfunction could help in identifying therapeutic approaches specific for each path. Most of our knowledge about diabetes pathophysiology has been obtained from studies on animal models, which do not fully recapitulate human diabetes phenotypes. Currently, human pluripotent stem cell (hPSC) technology is a powerful tool for generating in vitro human models, which could provide key information about the disease pathogenesis and provide cells for personalized therapies. The recent progress in generating functional hPSC-derived β cells in combination with the rapid development in genomic and genome-editing technologies offer multiple options to understand the cellular and molecular mechanisms underlying the development of different types of diabetes. Recently, several in vitro hPSC-based strategies have been used for studying monogenic and polygenic forms of diabetes. This review summarizes the current knowledge about different hPSC-based diabetes models and how these models improved our current understanding of the pathophysiology of distinct forms of diabetes. Also, it highlights the progress in generating functional β cells in vitro, and discusses the current challenges and future perspectives related to the use of the in vitro hPSC-based strategies.

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.

The metabolic syndrome in heart failure: insights to specific mechanisms

The presence of comorbidities significantly influences long-term morbidity and mortality of symptomatic and asymptomatic heart failure (HF) patients. Metabolic syndrome and diabetic cardiomyopathy are two clinical conditions that share multiple pathophysiological mechanisms and that might be both responsible for cardiac dysfunction. However, it is argued whether metabolic syndrome (MS) independently increases HF risk or the association between MS and HF merely reflects the impact of individual risk factors included in its definition on HF development. Similarly, in the context of diabetic cardiomyopathy, many aspects are still challenging starting from the definition up to the therapeutic management. In this clinical review, we focused the attention on molecular pathways, myocyte alterations, and specific patterns of metabolic syndrome and diabetic cardiomyopathy in order to better define the potential diagnostic and therapeutic approaches of these two pathological conditions.

The functions of LncRNA in the heart

Cardiovascular disease is a major cause of death and disability worldwide. Recently, increasing evidence has demonstrated that various lncRNAs play critical roles in the pathogenesis of cardiovascular diseases, including myocardial ischemia and reperfusion (I/R) injury. LncRNAs are transcripts longer than 200 nucleotides. They are considered a class of dynamic noncoding RNAs known to be involved in physiological and pathological conditions with regulatory and structural roles in numerous biological processes, including genomic imprinting, epigenetic regulation, cell proliferation, development, aging and apoptosis. They are emerging as potential key regulators of a variety of cardiovascular diseases. However, the roles of lncRNAs in the heart function remain largely unknown. The purpose of this review was to summarize the functions of lncRNAs in the heart and discuss the challenges and possible strategies of lncRNA research for cardiovascular disease.

Associated Targets of the Antioxidant Cardioprotection of Ganoderma lucidum in Diabetic Cardiomyopathy by Using Open Targets Platform: A Systematic Review

Even with substantial advances in cardiovascular therapy, the morbidity and mortality rates of diabetic cardiomyopathy (DCM) continually increase. Hence, a feasible therapeutic approach is urgently needed. Objectives. This work is aimed at systemically reviewing literature and addressing cell targets in DCM through the possible cardioprotection of G. lucidum through its antioxidant effects by using the Open Targets Platform (OTP) website. Methods. The OTP website version of 19.11 was accessed in December 2019 to identify the studies in DCM involving G. lucidum. Results. Among the 157 cell targets associated with DCM, the mammalian target of rapamycin (mTOR) was shared by all evidence, drug, and text mining data with 0.08 score association. mTOR also had the highest score association 0.1 with autophagy in DCM. Among the 1731 studies of indexed PubMed articles on G. lucidum published between 1985 and 2019, 33 addressed the antioxidant effects of G. lucidum and its molecular signal pathways involving oxidative stress and therefore were included in the current work. Conclusion. mTOR is one of the targets by DCM and can be inhibited by the antioxidative properties of G. lucidum directly via scavenging radicals and indirectly via modulating mTOR signal pathways such as Wnt signaling pathway, Erk1/2 signaling, and NF-κB pathways.

RUNX1: an emerging therapeutic target for cardiovascular disease

Runt-related transcription factor-1 (RUNX1), also known as acute myeloid leukaemia 1 protein (AML1), is a member of the core-binding factor family of transcription factors which modulate cell proliferation, differentiation, and survival in multiple systems. It is a master-regulator transcription factor, which has been implicated in diverse signalling pathways and cellular mechanisms during normal development and disease. RUNX1 is best characterized for its indispensable role for definitive haematopoiesis and its involvement in haematological malignancies. However, more recently RUNX1 has been identified as a key regulator of adverse cardiac remodelling following myocardial infarction. This review discusses the role RUNX1 plays in the heart and highlights its therapeutic potential as a target to limit the progression of adverse cardiac remodelling and heart failure.

A Mitochondrial Approach to Cardiovascular Risk and Disease

BACKGROUND

Cardiovascular diseases (CVDs) are a leading risk factor for mortality worldwide and the number of CVDs victims is predicted to rise through 2030. While several external parameters (genetic, behavioral, environmental and physiological) contribute to cardiovascular morbidity and mortality; intrinsic metabolic and functional determinants such as insulin resistance, hyperglycemia, inflammation, high blood pressure and dyslipidemia are considered to be dominant factors.

METHODS

Pubmed searches were performed using different keywords related with mitochondria and cardiovascular disease and risk. In vitro, animal and human results were extracted from the hits obtained.

RESULTS

High cardiac energy demand is sustained by mitochondrial ATP production, and abnormal mitochondrial function has been associated with several lifestyle- and aging-related pathologies in the developed world such as diabetes, non-alcoholic fatty liver disease (NAFLD) and kidney diseases, that in turn can lead to cardiac injury. In order to delay cardiac mitochondrial dysfunction in the context of cardiovascular risk, regular physical activity has been shown to improve mitochondrial parameters and myocardial tolerance to ischemia-reperfusion (IR). Furthermore, pharmacological interventions can prevent the risk of CVDs. Therapeutic agents that can target mitochondria, decreasing ROS production and improve its function have been intensively researched. One example is the mitochondria-targeted antioxidant MitoQ10, which already showed beneficial effects in hypertensive rat models. Carvedilol or antidiabetic drugs also showed protective effects by preventing cardiac mitochondrial oxidative damage.

CONCLUSION

This review highlights the role of mitochondrial dysfunction in CVDs, also show-casing several approaches that act by improving mitochondrial function in the heart, contributing to decrease some of the risk factors associated with CVDs.

Female sex and Western-style diet protect mouse resistance arteries during acute oxidative stress

A Western-style diet (WD; high in fat and carbohydrates) increases vascular oxidative stress. We hypothesized that vascular cells adapt to a WD by developing resilience to oxidative stress. Male and female C57BL/6J mice (4 wk of age) were fed a control diet (CD) or a WD for 16-20 wk. Superior epigastric arteries (SEAs; diameter, ~125 µm) were isolated and pressurized for study. Basal reactive oxygen species production was greatest in SEAs from males fed the WD. During exposure to H₂O₂ (200 μM, 50 min), propidium iodide staining identified nuclei of disrupted endothelial cells (ECs) and smooth muscle cells (SMCs). For mice fed the CD, death of SMCs (21%) and ECs (6%) was greater (P < 0.05) in SEAs from males than females (9% and 2%, respectively). WD consumption attenuated cell death most effectively in SEAs from males. With no difference at rest, H₂O₂ increased intracellular Ca²⁺ concentration ([Ca²⁺]_i) to the greatest extent in SEAs from males, as shown by fura 2 fluorescence. Selective disruption of the endothelium (luminal air bubble) increased [Ca²⁺]_i and SMC death during H₂O₂ exposure irrespective of sex; the WD reduced both responses most effectively in males. Nonselective transient receptor potential (TRP) channel inhibition (ruthenium red, 5 μM) attenuated the rise of [Ca²⁺]_i, as did selective inhibition of TRP vanilloid type 4 (TRPV4) channels (HC-067047, 1 μM), which also attenuated cell death. In contrast, inhibition of voltage-gated Ca²⁺ channels (diltiazem, 50 μM) was without effect. Thus, for resistance arteries during acute oxidative stress: 1) ECs are more resilient than (and can protect) SMCs, 2) vessels from females are inherently more resilient than those from males, and 3) a WD increases vascular resilience by diminishing TRPV4 channel-dependent Ca²⁺ entry.

The role of lncRNA MALAT1 in cardiovascular disease

Cardiovascular disease (CVD) is the first leading cause of death worldwide. Understanding the molecular mechanism of signaling pathways involved in pathology of CVD is benefit for targeted therapeutics. Recently, long non-coding RNAs (lncRNAs) are found and involved in regulation of pathology of CVD at different levels. Among them, MALAT1 attracted more attention as it was profoundly expressed in endothelial cells or cardiomyocytes in response to the risk factors of CVD, such as hypoxia, high glucose, cytokine, and oxidative stress. In this review, we summarize recent progresses in research on the molecular mechanism of MALAT1 on regulating the pathophysiological processes of CVD as well as its potential therapeutic applications.

Body mass index in women aged 18 to 45 and subsequent risk of heart failure

BACKGROUND

The incidence of heart failure (HF) is decreasing in older ages, but increasing rates have been observed among younger persons in Sweden. Therefore, we investigated the relationship between risk of hospitalization for HF and body mass index (BMI).

METHODS

This was a prospective registry-based cohort study. We included 1,374,031 women aged 18-45 years (mean age 27.9 years) who gave birth during 1982-2014, and were registered in the Medical Birth Register. Information on hospitalization because of HF was collected through linkage to the National Inpatient Register.

RESULTS

Compared to women with a BMI of 20-<22.5 kg/m², women with a BMI of 22.5-<25.0 had a hazard ratio (HR) of 1.24 (95% confidence interval (CI), 1.10-1.39) for HF after adjustment for age, year, parity, baseline disorders, smoking, and education. The HR (95% CI) increased to 1.56 (1.36-1.78), 2.39 (2.05-2.78), 2.82 (2.43-3.28), and 4.51 (3.63-5.61) in women with a BMI of 25-<27.5, 27.5-<30, 30-<35, and ≥35 kg/m², respectively. The multiple-adjusted HRs (95% CI) associated with risk of HF per one-unit increase in BMI in women with a BMI ≥ 22.5 kg/m² ranged from 1.01 (0.97-1.06) for HF related to valvular disease to 1.14 (1.12-1.15) for coronary heart disease, diabetes, or hypertension.

CONCLUSION

Increasing body weight was strongly associated with the risk of early HF in women. Compared with lean women, the risk for HF started to increase at high-normal BMI levels, and was nearly five-fold in women with a BMI ≥ 35 kg/m².

Nitric oxide mediated the effects of nebivolol in cardiorenal syndrome

OBJECTIVES

Despite several proposed mechanisms for the pathophysiology of cardiorenal syndrome (CRS), the exact mechanism remains unclear. Nitrosative stress has been argued as a key mechanism recently. Nebivolol is a beta-blocker with nitric oxide (NO)-releasing effect. In the present study, NO-mediated effects of two different treatment regimes of nebivolol in CRS were studied.

MATERIALS AND METHODS

Rats were divided into: sham-operated (sham-control), myocardial infarction (MI)-induced, (MI-control) early nebivolol-treated (MI-neb1) and late nebivolol-treated (Mı-neb2) groups. The effects of nebivolol were assessed both in the early and late period of MI by histologic, hemodynamic and biologic studies.

RESULTS

Developed MI model was in line with the heart failure with preserved ejection fraction. Focal and total tubular damage findings were observed in MI-control group both in early and late period of MI. In parallel, subclinical functional damage was transformed into chronic renal dysfunction in this group. Increased inducible nitric oxide synthase (iNOS) and endothelial NOS (eNOS) together with decreased neuronal NOS (nNOS) levels were in parallel with the increased inflammation and nitrosative stress biomarkers. Nebivolol effectively prevented both subclinical and clinical nephropathy. There was no statistical difference between the nebivolol treatment regimes.

CONCLUSION

The beneficial effects of nebivolol were closely related to the reduction of nitrosative damages as well as hemodynamic alterations. The NO-mediated effects were: prevention of nitrosative damage by decreasing iNOS, preservation of nNOS in order to maintain glomerular filtration rate (GFR), and restoration of eNOS in the late period of MI. On contrary to our previous work, early nebivolol administration had a similar effect with delayed administration of nebivolol on CRS.

Exercise does not ameliorate cardiac dysfunction in obese mice exposed to fine particulate matter

BACKGROUND

Studies have demonstrated that exposure to fine particulate matter (PM_2.5) is linked to cardiovascular disease (CVD), which is exacerbated in patients with pre-existing conditions such as obesity. In the present study, we examined cardiac function of obese mice exposed to PM_2.5 and determined if mild exercise affected cardiac function.

METHODS

Obese mice (ob/ob) (leptin deficient, C57BL/6J background) were exposed to either filtered air (FA) or PM_2.5 at an average concentration of 32 μg/m³ for 6 h/day, 5 days/week for 9 months. Following exposure, mice were divided into four groups: (1) FA sedentary, (2) FA treadmill exercise, (3) PM_2.5 sedentary, and (4) PM_2.5 treadmill exercise and all mice were analyzed after 8 weeks of exercise training.

RESULTS

Echocardiography showed increased left ventricular end systolic (LVESd) and diastolic (LVEDd) diameters in PM_2.5 sedentary mice compared to FA sedentary mice. There was increased expression of ICAM1, VCAM and CRP markers in sedentary PM_2.5 mice compared to FA mice. Both FA and PM_2.5 exercised mice showed decreased posterior wall thickness in systole compared to FA sedentary mice, coupled with altered expression of inflammatory markers following exercise.

CONCLUSION

Obese mice exposed to PM_2.5 for 9 months showed cardiac dysfunction, which was not improved following mild exercise training.

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

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

Cardiomyopathy Associated with Diabetes: The Central Role of the Cardiomyocyte

The term diabetic cardiomyopathy (DCM) labels an abnormal cardiac structure and performance due to intrinsic heart muscle malfunction, independently of other vascular co-morbidity. DCM, accounting for 50%–80% of deaths in diabetic patients, represents a worldwide problem for human health and related economics. Optimal glycemic control is not sufficient to prevent DCM, which derives from heart remodeling and geometrical changes, with both consequences of critical events initially occurring at the cardiomyocyte level. Cardiac cells, under hyperglycemia, very early undergo metabolic abnormalities and contribute to T helper (Th)-driven inflammatory perturbation, behaving as immunoactive units capable of releasing critical biomediators, such as cytokines and chemokines. This paper aims to focus onto the role of cardiomyocytes, no longer considered as “passive” targets but as “active” units participating in the inflammatory dialogue between local and systemic counterparts underlying DCM development and maintenance. Some of the main biomolecular/metabolic/inflammatory processes triggered within cardiac cells by high glucose are overviewed; particular attention is addressed to early inflammatory cytokines and chemokines, representing potential therapeutic targets for a prompt early intervention when no signs or symptoms of DCM are manifesting yet. DCM clinical management still represents a challenge and further translational investigations, including studies at female/male cell level, are warranted.

Predictors of early cardiac changes in patients with type 1 diabetes mellitus: An echocardiography-based study

In patients with type 1 diabetes mellitus (T1DM) imaging studies have demonstrated an increased prevalence of left ventricular diastolic dysfunction and increased left ventricular mass (LVM) unrelated to arterial hypertension and ischemic heart disease. The aim of our study was to identify potential predictors of early subclinical changes in cardiac chamber size and function in such patients. Sixty-one middle-aged asymptomatic normotensive patients with T1DM were included in the study. Conventional and tissue Doppler echocardiography was performed and fasting serum levels of glucose, glycated hemoglobin (HbA1c), lipids, and creatinine were measured. We found moderate bivariate correlations of body mass index (BMI) with left atrial volume (r = 0.47, p < 0.01), LVM (r = 0.42, p < 0.01), left ventricular relative wall thickness (r = 0.32, p = 0.01), and all observed parameters of diastolic function of both ventricles. The five-year average value of HbA1c weakly correlated with the Doppler index of left ventricular filling pressure E/e´sept (r = 0.27, p = 0.04). We found no significant association of diabetes duration, five-year trend of HbA1c, serum lipids, and glomerular filtration rate with cardiac structure and function. After adjusting for other parameters, BMI remained significantly associated with left atrial volume, LVM as well as with the transmitral Doppler ratio E/A. In our study, BMI was the only observed parameter significantly associated with subclinical structural and functional cardiac changes in the asymptomatic middle-aged patients with T1DM.

Established and Emerging Mechanisms of Diabetic Cardiomyopathy

Diabetes mellitus increases the risk for the development of heart failure even in the absence of coronary artery disease and hypertension, a cardiac entity termed diabetic cardiomyopathy (DC). Clinically, DC is increasingly recognized and typically characterized by concentric cardiac hypertrophy and diastolic dysfunction, ultimately resulting in heart failure with preserved ejection fraction (HFpEF) and potentially even heart failure with reduced ejection fraction (HFrEF). Numerous molecular mechanisms have been proposed to underlie the alterations in myocardial structure and function in DC, many of which show similar alterations in the failing heart. Well investigated and established mechanisms of DC include increased myocardial fibrosis, enhanced apoptosis, oxidative stress, impaired intracellular calcium handling, substrate metabolic alterations, and inflammation, among others. In addition, a number of novel mechanisms that receive increasing attention have been identified in recent years, including autophagy, dysregulation of microRNAs, epigenetic mechanisms, and alterations in mitochondrial protein acetylation, dynamics and quality control. This review aims to provide an overview and update of established underlying mechanisms of DC, as well as a discussion of recently identified and emerging mechanisms that may also contribute to the structural and functional alterations in DC.

Diabetic Cardiomyopathy: Definition, Diagnosis, and Therapeutic Implications

A strict bidirectional relationship exists between diabetes mellitus and heart failure. Diabetic cardiomyopathy is a specific cardiac manifestation of patients with diabetes characterized by left ventricular hypertrophy and diastolic dysfunction in the early phase up to overt heart failure with reduced systolic function in the advanced stages. The pathogenesis of this condition is multifactorial and recognizes as main promoting factors the presence of insulin resistance and hyperglycemia. Diabetic cardiomyopathy exerts a negative prognostic impact in affected patients and no target treatments are currently available. More efforts are needed to better define the diagnostic and therapeutic approach in this specific setting.

The effect of apelin-13 on pancreatic islet beta cell mass and myocardial fatty acid and glucose metabolism of experimental type 2 diabetic rats

Apelin, a new identified adipokine, and its G protein-coupled receptor named APJ are widely expressed in various tissues. Apelin has been found to play important roles in the physiopathology of multiple diseases. Our aim is to assess the effect of long-term apelin treatment on serum insulin level and pancreatic islet beta-cell mass in the late stage of type 2 diabetes without hyperinsulinemia and to investigate the role of apelin in myocardial fatty acid and glucose metabolism. In the present study, the high-fat diet fed-streptozotocin-induced experimental type 2 diabetic rats were given once daily intraperitoneal injection of apelin-13 (0.1 μmol/kg) for 10 weeks. We observed that apelin significantly improved serum insulin reduction and reduced hyperglycemia. Histologic analysis showed that long-term apelin treatment significantly increased pancreatic islet beta cell mass. Exogenous apelin failed to change dyslipidaemia of type 2 diabetic rats. Apelin treatment markedly decreased elevated myocardial FFA and glycogen content. Treatment of type 2 diabetic rats with apelin markedly reduced increased gene expressions of the cardiac fatty acid transporter CD36, CPT-1, and Peroxisome proliferator-activated receptor (PPAR)-α. Whereas the gene levels of citrate synthase and peroxisome proliferator-activated receptor γ coactivator 1-α (PGC1-α), a transcriptional coactivator, mediating mitochondrial biogenesis in heart were unaltered in response to exogenous apelin. Taken together, longer-term apelin treatment prevented pancreatic beta-cell loss or failure in experimental type 2 diabetic rats. Apelin can regulate myocardial metabolism. Apelin reduced myocadial fatty acid uptake and oxidation through inhibiting PPAR-α but did not affect myocardial mitochondrial biogenesis in type 2 diabetic rats.

Stem-cell based organ-on-a-chip models for diabetes research

Diabetes mellitus (DM) ranks among the severest global health concerns of the 21st century. It encompasses a group of chronic disorders characterized by a dysregulated glucose metabolism, which arises as a consequence of progressive autoimmune destruction of pancreatic beta-cells (type 1 DM), or as a result of beta-cell dysfunction combined with systemic insulin resistance (type 2 DM). Human cohort studies have provided evidence of genetic and environmental contributions to DM; yet, these studies are mostly restricted to investigating statistical correlations between DM and certain risk factors. Mechanistic studies, on the other hand, aimed at re-creating the clinical picture of human DM in animal models. A translation to human biology is, however, often inadequate owing to significant differences between animal and human physiology, including the species-specific glucose regulation. Thus, there is an urgent need for the development of advanced human in vitro models with the potential to identify novel treatment options for DM. This review provides an overview of the technological advances in research on DM-relevant stem cells and their integration into microphysiological environments as provided by the organ-on-a-chip technology.

Early dysregulation of cardiac-specific microRNA-208a is linked to maladaptive cardiac remodelling in diabetic myocardium

Background

The diabetic heart undergoes remodelling contributing to an increased incidence of heart failure in individuals with diabetes at a later stage. The molecular regulators that drive this process in the diabetic heart are still unknown.

Methods

Real-time (RT) PCR analysis was performed to determine the expression of cardiac specific microRNA-208a in right atrial appendage (RAA) and left ventricular (LV) biopsy tissues collected from diabetic and non-diabetic patients undergoing coronary artery bypass graft surgery. To determine the time-dependent changes, cardiac tissue were collected from type 2 diabetic mice at different age groups. A western blotting analysis was conducted to determine the expression of contractile proteins α- and β-myosin heavy chain (MHC) and thyroid hormone receptor-α (TR-α), the negative regulator of β-MHC. To determine the beneficial effects of therapeutic modulation of miR-208a, high glucose treated adult mouse HL-1 cardiomyocytes were transfected with anti-miR-208a.

Results

RT-PCR analysis showed marked upregulation of miR-208a from early stages of diabetes in type 2 diabetic mouse heart, which was associated with a marked increase in the expression of pro-hypertrophic β-MHC and downregulation of TR-α. Interestingly, upregulation of miR-208a preceded the switch of α-/β-MHC isoforms and the development of diastolic and systolic dysfunction. We also observed significant upregulation of miR-208a and modulation of miR-208a associated proteins in the type 2 human diabetic heart. Therapeutic inhibition of miR-208a activity in high glucose treated HL-1 cardiomyocytes prevented the activation of β-MHC and hence the hypertrophic response.

Conclusion

Our results provide the first evidence that early modulation of miR-208a in the diabetic heart induces alterations in the downstream signaling pathway leading to cardiac remodelling and that therapeutic inhibition of miR-208a may be beneficial in preventing diabetes-induced adverse remodelling of the heart.

Right ventricular dysfunction and remodeling in diabetic cardiomyopathy

The increasing prevalence of diabetic cardiomyopathy (DCM) is an important threat to health worldwide. While left ventricular (LV) dysfunction in DCM is well recognized, the accurate detection, diagnosis, and treatment of changes in right ventricular (RV) structure and function have not been well characterized. The pathophysiology of RV dysfunction in DCM may share features with LV diastolic and systolic dysfunction, including pathways related to insulin resistance and oxidant injury, although the RV has a unique cellular origin and composition and unique biomechanical properties and is coupled to the lower-impedance pulmonary vascular bed. In this review, we discuss potential mechanisms responsible for RV dysfunction in DCM and review the imaging approaches useful for early detection, protection, and intervention strategies. Additional data are required from animal models and clinical trials to better identify the onset and features of altered RV and pulmonary vascular structure and function during the onset and progression of DCM and to determine the efficacy of early detection and treatment of RV dysfunction on clinical symptoms and outcomes.

Exercise Training-Induced Changes in MicroRNAs: Beneficial Regulatory Effects in Hypertension, Type 2 Diabetes, and Obesity

MicroRNAs are small non-coding RNAs that regulate gene expression post-transcriptionally. They are involved in the regulation of physiological processes, such as adaptation to physical exercise, and also in disease settings, such as systemic arterial hypertension (SAH), type 2 diabetes mellitus (T2D), and obesity. In SAH, microRNAs play a significant role in the regulation of key signaling pathways that lead to the hyperactivation of the renin-angiotensin-aldosterone system, endothelial dysfunction, inflammation, proliferation, and phenotypic change in smooth muscle cells, and the hyperactivation of the sympathetic nervous system. MicroRNAs are also involved in the regulation of insulin signaling and blood glucose levels in T2D, and participate in lipid metabolism, adipogenesis, and adipocyte differentiation in obesity, with specific microRNA signatures involved in the pathogenesis of each disease. Many studies report the benefits promoted by exercise training in cardiovascular diseases by reducing blood pressure, glucose levels, and improving insulin signaling and lipid metabolism. The molecular mechanisms involved, however, remain poorly understood, especially regarding the participation of microRNAs in these processes. This review aimed to highlight microRNAs already known to be associated with SAH, T2D, and obesity, as well as their possible regulation by exercise training.

Effect of Astragalus Polysaccharides on Cardiac Dysfunction in db/db Mice with Respect to Oxidant Stress

OBJECTIVE

Oxidant stress plays an important role in the development of diabetic cardiomyopathy. Previously we reported that Astragalus polysaccharides (APS) rescued heart dysfunction and cardinal pathological abnormalities in diabetic mice. In the current study, we determined whether the effect of APS on diabetic cardiomyopathy was associated with its impact on oxidant stress.

METHODS

Db/db diabetic mice were employed and administered with APS. The hematodynamics, cardiac ultra-structure, apoptosis, and ROS formation of myocardium were assessed. The cardiac protein expression of apoptosis target genes (Bax, Bcl-2, and caspase-3) and oxidation target genes (Gpx, SOD2, t/p-JNK, catalase, t/p-p38 MAPK, and t/p-ERK) were evaluated, respectively.

RESULTS

APS therapy improved hematodynamics and cardinal ultra-structure with reduced apoptosis and ROS formation in db/db hearts. In addition, APS therapy inhibited the protein expression of apoptosis target genes (Bax, Bcl-2, and caspase-3) and regulated the protein expression of oxidation target genes (enhancing Gpx, SOD2, and catalase, while reducing t/p-JNK, t/p-ERK, and t/p-p38 MAPK) in db/db hearts.

CONCLUSION

Our findings suggest that APS has benefits in diabetic cardiomyopathy, which may be partly associated with its impact on cardiac oxidant stress.