Diabetic Cardiomyopathy; Summary of 41 Years

The Relationship Between Insulin Resistance Indicated by Triglyceride and Glucose Index and Left Ventricular Hypertrophy and Decreased Left Ventricular Diastolic Function with Preserved Ejection Fraction

Aim

The evidence on the association between insulin resistance (IR) and the prevalence or incidence of cardiac dysfunction has been controversial, and the relationship between pre-diabetic IR and cardiac function is lacking. Large sample studies in the Chinese general population are urgently needed to explore the association between IR and the risk of left ventricular hypertrophy (LVH) and decreased left ventricular diastolic function with preserved ejection fraction (LVDFpEF).

Methods

Based on a National Health Check-up database in China, we conducted a multicenter cross-sectional retrospective study in 344,420 individuals. Furthermore, at a single center, we performed two retrospective longitudinal studies encompassing 8270 and 5827 individuals to investigate the association between IR and the development of new-onset LVH and LVDFpEF, respectively. The median follow-up duration exceeded 2.5 years. The triglyceride and glucose (TyG) index, known for its high sensitivity in detecting IR, serves as a reliable alternative marker of IR. The logistic and cox proportional hazard regression models were used to determine the relationships.

Results

In the cross-sectional study, IR showed a positive association with the prevalence of LVH and decreased LVDFpEF after adjusting for confounders. In the longitudinal cohort, IR was also correlated with the new onset of LVH and decreased LVDFpEF, with hazard ratios (HR) of 1.986 (95% CI: 1.307, 3.017) and 1.386 (95% CI: 1.167, 1.647) in the fourth quartile of TyG levels compared to the lowest quartile, respectively, after adjusting for confounders. The subgroup analysis in non-hypertensive or non-diabetic people and the sensitivity analysis in the population with homeostasis model assessment of insulin resistance (HOMA-IR) further verified the above-mentioned results.

Conclusion

IR was associated with LVH and decreased LVDFpEF. Effective management of IR may prevent or delay the development of adverse LVH and decreased LVDFpEF.

[Resveratrol alleviates hyperglycemia-induced cardiomyocyte hypertrophy by maintaining mitochondrial homeostasis via enhancing SIRT1 expression]

OBJECTIVE

To investigate whether resveratrol alleviates hyperglycemia-induced cardiomyocyte hypertrophy by enhancing the expression of silent information regulation 2 homolog 1 (SIRT1) to maintain mitochondrial homeostasis.

METHODS

Rat cardiomyocytes H9c2 cells with or without lentivirus-mediated mRNA interference of SIRT1 were cultured in high glucose (HG) and treated with resveratrol for 72 h. The changes in superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, reactive oxygen species (ROS) level, and relative surface of the cells were examined, and the mRNA expressions of atrial natriuretic factor (ANF) and brain natriuretic peptide (BNP) and protein expressions of SIRT1, mitochondrial fusion related proteins optic atrophy protein 1 (OPA1) and mitofusin 2, mitochondrial division related proteins dynamin-related protein 1 (DRP1) and fission protein 1 (FIS1), and mitophagy-related proteins BNIP3L and LC3 were detected using RT-qPCR and Western blotting.

RESULTS

HG exposure significantly decreased SOD activity, increased MDA content, ROS production, relative cell surface, and the mRNA expressions of ANF and BNP in the cardiomyocytes; the protein expressions of SIRT1, OPA1, mitofusin 2 and BNIP3L and LC3-Ⅱ/LC3-Ⅰ ratio were all decreased and the protein expressions of DRP1 and FIS1 increased in HG-exposed cells (P<0.01). All these changes in HG-exposed cardiomyocytes were significantly alleviated by treatment with resveratrol (P<0.05). The protective effects of resveratrol against HG exposure in the cardiomyocytes were obviously attenuated by transfection of the cells with si-SIRT1 (P<0.05).

CONCLUSION

Resveratrol inhibits hyperglycemia-induced cardiomyocyte hypertrophy by reducing oxidative stress, the mechanisms of which involve enhancement of SIRT1 protein expression, regulation of mitochondrial fusion and division balance, and promoting BNIP3L-mediated mitophagy to maintain mitochondrial homeostasis in the cells.

LncRNA TUG1 Exacerbates Myocardial Fibrosis in Diabetic Cardiomyopathy by Modulating the microRNA-145a-5p/Cfl2 Axis

ABSTRACT

Nowadays, there is limited prevention and treatment for myocardial fibrosis in diabetic cardiomyopathy (DCM). Our study aimed to depict the mechanism of the lncRNA TUG1/miR-145a-5p/Cfl2 axis in DCM and to provide a molecular basis for the study of this disease. Male C57BL/6J mice were intraperitoneally injected with streptozotocin to establish DCM mouse models. The expression levels of lncRNA TUG1, miR-145a-5p, and Cfl2 in myocardial tissues of mice were tested by RT-qPCR or Western blot. Cardiac function was assessed by echocardiography. The contents of Ang-II, TNF-α, and IL-1β were measured using ELISA. The histopathological observation was performed by HE staining and Masson staining. The expression levels of myocardial fibrosis-related genes COL1A1, MMP2, and FN1 were determined by RT-qPCR. In addition, bioinformatics website, RIP assay, pull-down assay, and luciferase activity assay were conducted to verify the relationships of lncRNA TUG1, miR-145a-5p, and Cfl2. In the DCM mouse model, lncRNA TUG1 and Cfl2 expression levels were upregulated and miR-145a-5p expression was downregulated. Downregulation of lncRNA TUG1 improved cardiac function and myocardial fibrosis; decreased COL1A1, MMP2, and FN1 expression levels; as well as TNF-α, IL-1β, and Ang-II contents in myocardial tissues of DCM mice. Upregulation of miR-145a-5p showed the same trend as downregulation of lncRNA TUG1. In addition, upregulating miR-145a-5p reversed the promotion roles of lncRNA TUG1 on myocardial fibrosis in DCM mice, and upregulating Cfl2 compromised the improvement effect of downregulated lncRNA TUG1 on myocardial fibrosis in DCM mice. Mechanistically, there was a binding site between lncRNA TUG1 and miR-145a-5p, and miR-145a-5p had a targeting relationship with Cfl2. This study highlights that lncRNA TUG1 sponges miR-145a-5p to aggravate myocardial fibrosis in DCM mice by promoting Cfl2.

A Comprehensive Review on Beneficial Effects of Catechins on Secondary Mitochondrial Diseases

Mitochondria are the main sites for oxidative phosphorylation and synthesis of adenosine triphosphate in cells, and are known as cellular power factories. The phrase "secondary mitochondrial diseases" essentially refers to any abnormal mitochondrial function other than primary mitochondrial diseases, i.e., the process caused by the genes encoding the electron transport chain (ETC) proteins directly or impacting the production of the machinery needed for ETC. Mitochondrial diseases can cause adenosine triphosphate (ATP) synthesis disorder, an increase in oxygen free radicals, and intracellular redox imbalance. It can also induce apoptosis and, eventually, multi-system damage, which leads to neurodegenerative disease. The catechin compounds rich in tea have attracted much attention due to their effective antioxidant activity. Catechins, especially acetylated catechins such as epicatechin gallate (ECG) and epigallocatechin gallate (EGCG), are able to protect mitochondria from reactive oxygen species. This review focuses on the role of catechins in regulating cell homeostasis, in which catechins act as a free radical scavenger and metal ion chelator, their protective mechanism on mitochondria, and the protective effect of catechins on mitochondrial deoxyribonucleic acid (DNA). This review highlights catechins and their effects on mitochondrial functional metabolic networks: regulating mitochondrial function and biogenesis, improving insulin resistance, regulating intracellular calcium homeostasis, and regulating epigenetic processes. Finally, the indirect beneficial effects of catechins on mitochondrial diseases are also illustrated by the warburg and the apoptosis effect. Some possible mechanisms are shown graphically. In addition, the bioavailability of catechins and peracetylated-catechins, free radical scavenging activity, mitochondrial activation ability of the high-molecular-weight polyphenol, and the mitochondrial activation factor were also discussed.

Role of histone deacetylase inhibitors in diabetic cardiomyopathy in experimental models (Review)

In diabetes, metabolic dysregulation, caused by hyperglycemia, leads to both structural and functional changes in cardiomyocytes and subsequently leads to the development of cardiomyopathy. Histone deacetylases (HDAC) are enzymes that regulate gene transcription. Their actions have been examined in the development of multiple disorders, such as cardiovascular diseases and diabetes. The use of HDAC inhibitors (HDACIs), as potential therapeutic agents against disease progression has yielded promising results. The present review article reports preclinical trials identified in which HDACIs were administered to mice suffering from diabetic cardiomyopathy (DCM), and discusses the role and mechanisms of action of HDAC and HDACIs in DCM. A review of the literature was performed using the PubMed database, aiming to identify publications in the English language concerning the role of HDACIs in DCM. More specifically, key words, separately and in various combinations, such as HDACIs, HDAC, diabetes, cardiomyopathy, heart failure and ischemia/reperfusion injury, were used. Furthermore, the references from all the articles were cross-checked in order to include any other eligible studies. The full-text articles assessed for eligibility were eight, covering the period from 2015 to 2019; finally, all of them were included. The use of HDACIs exhibited encouraging results against DCM progression through various mechanisms, including the reduction of reactive oxygen species generation, inflammatory cytokine production and fibrosis, and an increase in autophagy and angiogenesis.

Exercise Augments the Effect of SGLT2 Inhibitor Dapagliflozin on Experimentally Induced Diabetic Cardiomyopathy, Possible Underlying Mechanisms

One of the most prevalent cardiovascular problems linked with type 2 diabetes mellitus (T2DM) is diabetic cardiomyopathy (DCM). DCM is associated with myocardial oxidative stress, inflammation, apoptosis, suppressed autophagy, extracellular matrix remodeling, and fibrosis. The current study aims to investigate the protective effect of sodium-glucose transport 2 inhibitor (SGLT2i) dapagliflozin and/or exercise on DCM. Thirty adult male Sprague Dawley rats are used. T2DM is induced by a 6-week high-fat diet (HFD) followed by a single intraperitoneal (IP) injection of 35 mg/kg streptozotocin (STZ). Rats are divided into five groups, control, diabetic (DM), DM + swimming, DM + dapagliflozin, and DM + dapagliflozin and swimming. Serum glucose, insulin, insulin resistance (HOMA-IR), and cardiac enzymes (CK-MB and lactate dehydrogenase (LDH) are measured. Heart specimens are used for evaluation of cellular oxidative stress markers malondialdehyde (MDA), antioxidant enzymes, glutathione (GSH), and catalase (CAT), as well as mRNA expression of TGF-β, MMP9, IL-1β, and TNF-α. Stained sections with haematoxylin and eosin (H & E) and Masson trichrome are used for histopathological evaluation and detection of fibrosis, respectively. Immunohistochemical staining for apoptosis (caspase-3), and autophagy (LC3) are also carried out. The combinations of SGLT2i and exercise exhibited the most significant cardioprotective effect. It improved diabetic-induced histopathological alterations in the myocardium and attenuated the elevation of serum blood glucose, CK-MB, LDH, myocardial MDA, and mRNA expression of TNF-α, IL-1β, TGF-β, MMP9, and the immune expression of caspase-3. Moreover, this combination increased the serum insulin, myocardial antioxidants GSH and CAT, and increase the immune expression of the LC-3. In conclusion, a combination of SGLT2i and exercise exerted a better antioxidant, anti-inflammatory, and antifibrotic effect in DCM. Moreover, the combination enhances the autophagic capacity of the heart.

Diabetic cardiomyopathy was attenuated by cinnamon treatment through the inhibition of fibro-inflammatory response and ventricular hypertrophy in diabetic rats

Diabetic cardiomyopathy (DCM) is a chronic complication of diabetes that emphasizes the urgency of developing new drug therapies. With an illustrious history in traditional medicine to improve diabetes, cinnamon has been shown to possess blood lipids lowering effects and antioxidative and anti-inflammatory properties. However, the extent to which it protects the diabetic heart has yet to be determined. Forty-eight rats were administered in the study and grouped as: control; diabetic; diabetic rats given 100, 200, or 400 mg/kg cinnamon extract, metformin (300 mg/kg), valsartan (30 mg/kg), or met/val (combination of both drugs), via gavage for six weeks. Fasting blood sugar (FBS) and markers of cardiac injury including creatine kinase-muscle/brain (CK-MB), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) were evaluated in blood samples. Malondialdehyde (MDA) levels, the total contents of thiol, superoxide dismutase (SOD), and catalase (CAT) activities were measured. Histopathology study and gene expression measurement of angiotensin II type 1 receptor (AT1), atrial natriuretic peptide (ANP), beta-myosin heavy chain (β-MHC), and brain natriuretic peptide (BNP) were done on cardiac tissue. FBS and cardiac enzyme indicators were reduced in all treated groups. A reduction in MDA level and enhancement in thiol content alongside with increase of SOD and CAT activities were observed in extract groups. The decrease of inflammation and fibrosis was obvious in treated groups, notably in the high-dose extract group. Furthermore, all treated diabetic groups showed a lowering trend in AT1, ANP, β-MHC, and BNP gene expression. Cinnamon extract, in addition to its hypoglycemic and antioxidant properties, can prevent diabetic heart damage by alleviating cardiac inflammation and fibrosis. PRACTICAL APPLICATIONS: This study found that cinnamon extract might protect diabetic heart damage by reducing inflammation and fibrosis in cardiac tissue, in addition to lowering blood glucose levels and increasing antioxidant activity. Our data imply that including cinnamon in diabetic participants' diets may help to reduce risk factors of cardiovascular diseases.

Emerging Role of LncRNA Regulation for NLRP3 Inflammasome in Diabetes Complications

Diabetes is a widespread metabolic disease with various complications, including diabetic nephropathy, retinopathy, cardiomyopathy, and other cardiovascular or cerebrovascular diseases. As the prevalence of diabetes increases in all age groups worldwide, diabetes and its complications cause an emerging public health burden. NLRP3 inflammasome is a complex of several proteins that play a critical role in inflammatory response and various diseases, including diabetes and its complications. Accumulating evidences indicate that NLRP3 inflammasome contributes to the development of diabetes and diabetic complications and that NLRP3 inflammation inactivation is beneficial in treating these illnesses. Emerging evidences suggest the critical role of long non-coding RNAs (lncRNAs) in regulating NLRP3 inflammasome activity in various diseases. LncRNAs are non-coding RNAs exceeding 200 nucleotides in length. Its dysregulation has been linked to the development of diseases, including diabetes. Recently, growing evidences hint that regulating lncRNAs on NLRP3 inflammasome is critical in developing and progressing diabetes and diabetic complications. Here, we discuss the role of lncRNAs in regulating NLRP3 inflammasome as well as its participation in diabetes and diabetic complications, providing novel insights into developing future therapeutic approaches for diabetes.

Ameliorative Effect of Flavonoid-rich Extracts from Gongronema latifolium Against Diabetic Cardiomyopathy via serpin A3 and socs3-a in Streptozocin Treated Rats

INTRODUCTION

The present study access the effect of the flavonoid-rich isolate from Gongronema latifolium against cardiomyopathy in a streptozotocin-rich extract.

MATERIAL AND METHODS

The flavonoid-rich isolate from G. latifolium leaf (FREGL) was prepared using a standard method. A single injection of streptozotocin was induced into the experimental rats. The experimental animals were divided into five groups as non-diabetic rats, diabetic control, diabetic rats administered low and high doses of FREGL (13 and 26 mg/kg), and metformin glibenclamide orally for 21 days. Hence, the experimental animals were sacrificed; blood and heart were harvested to determine diverse biochemical parameters, including the gene expressions of serpin A₃ and socs3-a as well as histological examination.

RESULTS

The results demonstrated that FREGL significantly (p < 0.05) reduced fasting blood glucose, total cholesterol, low density lipoprotein (LDL), triglyceride (TG), lipid peroxidation levels, as well as the activities of lactate dehydrogenase and creatine kinase-MB, including the relative gene expressions of serpin A₃ and Socs3-A in diabetic rats. Also, diabetic rats that received different doses of FREGL showed a substantial rise in insulin and high density lipoprotein (HDL) levels, and antioxidant enzyme activities, as well as, normal histoarchitecture of the heart tissues.

CONCLUSION

Therefore, FREGL may be beneficial in alleviating diabetic cardiomyopathy.

Granulocyte colony-stimulating factor reduces the endoplasmic reticulum stress in a rat model of diabetic cardiomyopathy

Prolonged endoplasmic reticulum (ER) stress contributes to the apoptosis of cardiomyocytes, which leads to the development of diabetic cardiomyopathy. Previously, we reported that the granulocyte colony-stimulating factor (G-CSF) reduces the cardiomyocyte apoptosis in diabetic cardiomyopathy; however, the precise mechanisms associated with this process are not yet fully understood. Therefore, in this study, we investigated whether the mechanism of the anti-apoptotic effect of G-CSF was associated with ER stress in a rat model of diabetic cardiomyopathy. Diabetic cardiomyopathy was induced in rats using a high-fat diet combined with the administration of a low-dose of streptozotocin. Diabetic rats were treated with G-CSF or saline for 5 days. Cardiac function was evaluated using serial echocardiography before and 4 weeks after treatment. The rate of cardiomyocyte apoptosis and the expression levels of proteins related to ER stress, including glucose-regulated protein 78 (GRP78), caspase-9, and caspase-12 were analyzed in the cardiac tissue. G-CSF treatment significantly reduced cardiomyocyte apoptosis in the diabetic myocardium and downregulated the expression levels of these proteins in diabetic rats treated with low-dose streptozotocin when compared to that in rats treated with saline. In addition, G-CSF treatment significantly downregulated the expression levels of proteins related to ER stress, such as GRP78, inositol-requiring enzyme-1α (IRE-1α), and C/EBP homologous protein (CHOP) in H9c2 cells under high glucose (HG) conditions. Moreover, G-CSF treatment significantly improved the diastolic dysfunction in serial echocardiography assessments. In conclusion, the anti-apoptotic effect of G-CSF may be associated with the downregulation of ER stress.

The MEK inhibitor U0126 ameliorates diabetic cardiomyopathy by restricting XBP1's phosphorylation dependent SUMOylation

Background: Chronic diabetes accelerates vascular dysfunction often resulting in cardiomyopathy but underlying mechanisms remain unclear. Recent studies have shown that the deregulated unfolded protein response (UPR) dependent on highly conserved IRE1α-spliced X-box- binding protein (XBP1s) and the resulting endoplasmic reticulum stress (ER-Stress) plays a crucial role in the occurrence and development of diabetic cardiomyopathy (DCM). In the present study, we determined whether targeting MAPK/ERK pathway using MEK inhibitor U0126 could ameliorate DCM by regulating IRE1α-XBP1s pathway.

Method: Three groups of 8-week-old C57/BL6J mice were studied: one group received saline injection as control (n=8) and two groups were made diabetic by streptozotocin (STZ) (n=10 each). 18 weeks after STZ injection and stable hyperglycemia, one group had saline treatment while the second group was treated with U0126 (1mg/kg/day), 8 weeks later, all groups were sacrificed. Cardiac function/histopathological changes were determined by echocardiogram examination, Millar catheter system, hematoxylin-eosin staining and western blot analysis. H9C2 cardiomyocytes were employed for in vitro studies.

Results: Echocardiographic, hemodynamic and histological data showed overt myocardial hypertrophy and worsened cardiac function in diabetic mice. Chronic diabetic milieu enhanced SUMOylation and impaired nuclear translocation of XBP1s. Intriguingly, U0126 treatment significantly ameliorated progression of DCM, and this protective effect was achieved through enriching XBP1s' nuclear accumulation. Mechanistically, U0126 inhibited XBP1s' phosphorylation on S348 and SUMOylation on K276 promoting XBP1s' nuclear translocation. Collectively, these results identify that MEK inhibition restores XBP1s-dependent UPR and protects against diabetes-induced cardiac remodeling.

Conclusion: The current study identifies previously unknown function of MEK/ERK pathway in regulation of ER-stress in DCM. U0126 could be a therapeutic target for the treatment of DCM.

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.

Dysregulation of circulating miRNAs promotes the pathogenesis of diabetes-induced cardiomyopathy

Diabetic Cardiomyopathy (DCM) is characterized by myocardial dysfunction caused by diabetes mellitus. After-effects of diabetic cardiomyopathy are far more lethal than non-diabetic cardiomyopathy. More than 300 million people suffer from diabetes and cardiovascular disorder which is expected to be elevated to an alarming figure of 450 million by 2030. Recent studies suggested that miRNA plays important role in the onset of diabetic cardiomyopathy. This study was designed to identify the miRNA that is responsible for the onset of diabetic cardiomyopathy using in silico and in vitro approaches. In this study, to identify the miRNA responsible for the onset of diabetic cardiomyopathy, in silico analysis was done to predict the role of these circulating miRNAs in type 2 diabetic cardiomyopathy. Shared miRNAs that are present in both diseases were selected for further analysis. Total RNA and miRNA were extracted from blood samples taken from type 2 diabetic patients as well as healthy controls to analyze the expression of important genes like AKT, VEGF, IGF, FGF1, ANGPT2 using Real-time PCR. The expression of ANGPT2 was up-regulated and AKT, VEGF, IGF, FGF1 were down-regulated in DCM patients as compared to healthy controls. The miRNA expression of miR-17 was up-regulated and miR-24, miR-150, miR-199a, miR-214, and miR-320a were down-regulated in the DCM patients as compared to healthy controls. This shows that dysregulation of target genes and miRNA may contribute towards the pathogenesis of DCM and more studies should be conducted to elucidate the role of circulating miRNAs to use them as therapeutic and diagnostic options.

Concurrent diabetes and heart failure: interplay and novel therapeutic approaches

Diabetes mellitus increases the risk of developing heart failure, and the co-existence of both diseases worsens cardiovascular outcomes, hospitalization and the progression of heart failure. Despite current advancements on therapeutic strategies to manage hyperglycemia, the likelihood of developing diabetes-induced heart failure is still significant, especially with the accelerating global prevalence of diabetes and an ageing population. This raises the likelihood of other contributing mechanisms beyond hyperglycemia in predisposing diabetic patients to cardiovascular disease risk. There has been considerable interest in understanding the alterations in cardiac structure and function in the diabetic patients, collectively termed as "diabetic cardiomyopathy". However, the factors that contribute to the development of diabetic cardiomyopathies is not fully understood. This review summarizes the main characteristics of diabetic cardiomyopathies, and the basic mechanisms that contribute to its occurrence. This includes perturbations in insulin resistance, fuel preference, reactive oxygen species generation, inflammation, cell death pathways, neurohormonal mechanisms, advanced glycated end-products accumulation, lipotoxicity, glucotoxicity, and posttranslational modifications in the heart of the diabetic. This review also discusses the impact of antihyperglycemic therapies on the development of heart failure, as well as how current heart failure therapies influence glycemic control in diabetic patients. We also highlight the current knowledge gaps in understanding how diabetes induces heart failure.

Role of some serum biomarkers in the early detection of diabetic cardiomyopathy

AIM

To assess the role of serum biomarkers in early prediction of diabetic cardiomyopathy.

MATERIALS AND METHODS

The participants were three groups of Type 2 diabetes mellitus (DM) patients having diastolic dysfunction (DM-DD), systolic dysfunction (DM-SD) and normal echocardiography (DM-N) with two control groups: non-DM diastolic dysfunction patients (DD) and healthy controls. AGEs, TNF-α, IL-6, IGFBP-7, creatinine and insulin were assessed.

RESULTS

TNF-α, AGEs, creatinine and insulin panel had area under the curve (AUC) of 0.913 in distinguishing DM-DD from DM-N (78.7% sensitivity and 100% specificity). IL-6 and AGEs panel had AUC 0.795 for differentiating DM-SD from DM-DD (90.6% sensitivity). IL-6, TNF-α and AGEs panel had AUC 0.924 for differentiating diabetic cardiomyopathy from DM-N (85% sensitivity and specificity).

CONCLUSION

A panel of AGEs, IL-6, TNF-α, insulin and creatinine might be used for early detection of DM-DD among T2DM patients.

Protective effects of medicinal plant against diabetes induced cardiac disorder: A review

ETHNOPHARMACOLOGY RELEVANCE

Nowadays, there is an increase in global tendency to use medicinal plants as preventive and therapeutic agents to manage diabetes and its long-term complications such as cardiovascular disorders owing to their availability and valuable traditional background.

AIM OF STUDY

This review aims to introduce common medicinal plants, which have been demonstrated to have cardioprotective effects on diabetes and their mechanisms of action.

MATERIALS AND METHODS

Online literature databases, including Web of Sciences, PubMed, Science Direct, Scopus and Google Scholar were searched without date limitation by May 2020. The following keywords (natural products or medicinal plants or herbal medicine or herb or extract) and (diabetes or antidiabetic or hyperglycemic) and (cardiomyopathy or heart or cardioprotective or cardiac or cardio) were used, and after excluding non-relevant articles, 81 original English articles were selected.

RESULTS

The surveyed medicinal plants induced cardioprotective effects mostly through increasing antioxidant effects leading to attenuating ROS production as well as by inhibiting inflammatory signaling pathways and related cytokines. Moreover, they ameliorated the Na+/K + ATPase pump, the L-type Ca₂⁺ channel current, and the intracellular ATP. They also reduced cardiac remodeling and myocardial cell apoptosis through degradation of caspase-3, Bax, P53 protein, enhancement of Bcl-2 protein expression as well as downregulation of TGFβ1 and TNFα expression. In addition, the extracts improved cardiac function through increasing EF% and FS% as well as restoring hemodynamic parameters.

CONCLUSIONS

The reviewed medicinal plants demonstrated cardioprotective manifestations in diabetes through intervention with mechanisms involved in the diabetic heart to restore cardiovascular complications.

Association between insulin resistance and left ventricular hypertrophy in asymptomatic, Black, sub-Saharan African, hypertensive patients: a case-control study

Background

Conflicting information exists regarding the association between insulin resistance (IR) and left ventricular hypertrophy (LVH). We described the associations between obesity, fasting insulinemia, homeostasis model assessment of insulin resistance (HOMA-IR), and LVH in Black patients with essential hypertension.

Methods

A case–control study was conducted at the Centre Médical de Kinshasa (CMK), the Democratic Republic of the Congo, between January and December 2019. Cases and controls were hypertensive patients with and without LVH, respectively. The relationships between obesity indices, physical inactivity, glucose metabolism and lipid disorder parameters, and LVH were assessed using linear and logistic regression analyses in simple and univariate exploratory analyses, respectively. When differences were observed between LVH and independent variables, the effects of potential confounders were studied through the use of multiple linear regression and in conditional logistic regression in multivariate analyses. The coefficients of determination (R²), adjusted odds ratios (aORs), and their 95% confidence intervals (95% CIs) were calculated to determine associations between LVH and the independent variables.

Results

Eighty-eight LVH cases (52 men) were compared against 132 controls (81 men). Variation in left ventricular mass (LVM) could be predicted by the following variables: age (19%), duration of hypertension (31.3%), body mass index (BMI, 44.4%), waist circumference (WC, 42.5%), glycemia (20%), insulinemia (44.8%), and HOMA-IR (43.7%). Hypertension duration, BMI, insulinemia, and HOMA-IR explained 68.3% of LVM variability in the multiple linear regression analysis. In the logistic regression model, obesity increased the risk of LVH by threefold [aOR 2.8; 95% CI (1.06–7.4); p = 0.038], and IR increased the risk of LVH by eightfold [aOR 8.4; 95 (3.7–15.7); p < 0.001].

Conclusion

Obesity and IR appear to be the primary predictors of LVH in Black sub-Saharan African hypertensive patients. The comprehensive management of cardiovascular risk factors should be emphasized, with particular attention paid to obesity and IR. A prospective population-based study of Black sub-Saharan individuals that includes the use of serial imaging remains essential to better understand subclinical LV deterioration over time and to confirm the role played by IR in Black sub-Saharan individuals with hypertension.

Diabetic Cardiomyopathy: Clinical and Metabolic Approach

BACKGROUND

Having in mind that diabetes mellitus (DM) and obesity are some of the greatest health challenges of the modern era, diabetic cardiomyopathy (DCM) is becoming more and more recognized in clinical practice. Main Text: Initially, DM is asymptomatic, but it may progress to diastolic and then systolic left ventricular dysfunction, which results in congestive heart failure. A basic feature of this DM complication is the absence of hemodynamically significant stenosis of the coronary blood vessels. Clinical manifestations are the result of several metabolic disorders that are present during DM progression. The complexity of metabolic processes, along with numerous regulatory mechanisms, has been the subject of research that aims at discovering new diagnostic (e.g. myocardial strain with echocardiography and cardiac magnetic resonance) and treatment options. Adequate glycaemic control is not sufficient to prevent or reduce the progression of DCM. Contemporary hypoglycemic medications, such as sodium-glucose transport protein 2 inhibitors, significantly reduce the frequency of cardiovascular complications in patients with DM. Several studies have shown that, unlike the above-stated medications, thiazolidinediones and dipeptidyl peptidase-4 inhibitors are associated with deterioration of heart failure.

CONCLUSION

Imaging procedures, especially myocardial strain with echocardiography and cardiac magnetic resonance, are useful to identify the early signs of DCM. Research and studies regarding new treatment options are still "in progress".

The effect of Rheum ribes L. on oxidative stress in diabetic rats

Objectives Rheum ribes L. is a perennial plant that belongs to the family of Polygonaceae, which is often used in traditional therapy because it possesses many bioactivities, such as antioxidant and antibacterial ones. Here we examined the effect of different R. ribes L. extracts on oxidative stress in experimental diabetic rats. Methods Thirty-six rats were divided into six groups as follows: group I, control group; group II, diabetic rats; group III, diabetic rats treated with the aqueous extract of R. ribes L. by gavage at 50 mg/kg for 15 days; group IV, diabetic rats treated by gavage with the ethanolic extract of R. ribes L. at 50 mg/kg for 15 days; group V, nondiabetic rats treated by gavage with the aqueous extract of R. ribes L. at 50 mg/kg for 15 days; group VI, nondiabetic rats treated by gavage with the ethanol extract of R. ribes L. at 50 mg/kg for 15 days. After 15 days, the animals were sacrificed and the liver and kidney tissues of each animal were isolated. Superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA) and glutathione peroxidase (GSH-Px) activities in the tissue samples were measured, and histopathologic examination was carried out. Results R. ribes L. was effective in reducing the oxidative stress and increasing the levels of the antioxidant enzymes. Increased levels of MDA and decreased levels of SOD, CAT and GSH-Px were observed in both the liver and kidney tissues in group II. Decreased levels of MDA and increased levels of SOD, CAT and GSH-Px were observed in group III compared with group II. In group IV, decreased levels of MDA and increased levels of SOD, CAT and GSH-Px were observed in comparison with group II. Conclusions Diabetes increases oxidative stress and causes a decrease in antioxidant enzyme levels. Both aqueous and ethanolic extracts of R. ribes L. decrease oxidative stress activity and increase the levels of antioxidant enzymes. The ethanol extract of R. ribes L. has a higher antioxidant effect than the aqueous extract.

Amelioration of risk factors associated with diabetic nephropathy in diet-induced pre-diabetic rats by an uracil-derived diimine ruthenium(II) compound

Diabetic renal injury advances through different stages of structural and functional changes in the glomerulus, therefore treatment during the pre-diabetic state could be used as therapeutic target in the management and prevention of diabetic nephropathy (DN). Once diagnosed, dietary interventions and pharmacological therapy have been recommended to manage DN and pre-diabetic related complications. However, poor patient compliance still results, therefore newer alternative drugs are required. High fat high carbohydrates (HFHC) diet was used to induce pre-diabetes for 20 weeks. After the induction, pre-diabetic rats were randomly allocated to respective treatment groups. Subcutaneous ruthenium(II) Schiff base complex injection (15 mg/kg) was administered to pre-diabetic rats in both the presence and absence of dietary intervention once a day every third day for 12 weeks. The administration of ruthenium(II) complex resulted in reduced blood glucose, aldosterone, fluid intake and urinary output which correlated with a restoration in plasma and urinary electrolytes along with plasma antioxidants concentration. Furthermore, there was a decrease in kidney injury molecule-1 (KIM-1) concentration, albumin excretion rate (AER) albumin creatinine ratio (ACR) and mRNA expression of podocin in urine in ruthenium-treated pre-diabetic rats. Ruthenium(II) Schiff base complex ameliorated renal function while preventing the progression of DN in prediabetic-treated rats.

Diabetic Cardiomyopathy: From Mechanism to Management in a Nutshell

Diabetic cardiomyopathy (DCM) is a significant complication of diabetes mellitus characterized by gradually failing heart with detrimental cardiac remodelings, such as fibrosis and diastolic and systolic dysfunction, which is not directly attributable to coronary artery disease. Insulin resistance and resulting hyperglycemia is the main trigger involved in the initiation of diabetic cardiomyopathy. There is a constellation of many pathophysiological events, such as lipotoxicity, oxidative stress, inflammation, inappropriate activation of the renin-angiotensin-aldosterone system, dysfunctional immune modulation promoting increased rate of cardiac cell injury, apoptosis, and necrosis, which ultimately culminates into interstitial fibrosis, cardiac stiffness, diastolic dysfunction, initially, and later systolic dysfunction too. These events finally lead to clinical heart failure of DCM. Herein, The pathophysiology of DCM is briefly discussed. Furthermore, potential therapeutic strategies currently used for DCM are also briefly mentioned.

Adeno-Associated Viral Transfer of Glyoxalase-1 Blunts Carbonyl and Oxidative Stresses in Hearts of Type 1 Diabetic Rats

Accumulation of methylglyoxal (MG) arising from downregulation of its primary degrading enzyme glyoxalase-1 (Glo1) is an underlying cause of diabetic cardiomyopathy (DC). This study investigated if expressing Glo1 in rat hearts shortly after the onset of Type 1 diabetes mellitus (T1DM) would blunt the development of DC employing the streptozotocin-induced T1DM rat model, an adeno-associated virus containing Glo1 driven by the endothelin-1 promoter (AAV2/9-Endo-Glo1), echocardiography, video edge, confocal imaging, and biochemical/histopathological assays. After eight weeks of T1DM, rats developed DC characterized by a decreased E:A ratio, fractional shortening, and ejection fraction, and increased isovolumetric relaxation time, E: e' ratio, and circumferential and longitudinal strains. Evoked Ca2+ transients and contractile kinetics were also impaired in ventricular myocytes. Hearts from eight weeks T1DM rats had lower Glo1 and GSH levels, elevated carbonyl/oxidative stress, microvascular leakage, inflammation, and fibrosis. A single injection of AAV2/9 Endo-Glo1 (1.7 × 1012 viron particles/kg) one week after onset of T1DM, potentiated GSH, and blunted MG accumulation, carbonyl/oxidative stress, microvascular leakage, inflammation, fibrosis, and impairments in cardiac and myocyte functions that develop after eight weeks of T1DM. These new data indicate that preventing Glo1 downregulation by administering AAV2/9-Endo-Glo1 to rats one week after the onset of T1DM, blunted the DC that develops after eight weeks of diabetes by attenuating carbonyl/oxidative stresses, microvascular leakage, inflammation, and fibrosis.

Mesenchymal stem cells ameliorate myocardial fibrosis in diabetic cardiomyopathy via the secretion of prostaglandin E2

BACKGROUND

Diabetic cardiomyopathy (DCM) is a cardiac complication of long-term uncontrolled diabetes and is characterized by myocardial fibrosis and abnormal cardiac function. Mesenchymal stem cells (MSCs) are multipotent cells with immunoregulatory and secretory functions in diabetes and heart diseases. However, very few studies have focused on the effect and the underlying mechanism of MSCs on myocardial fibrosis in DCM. Therefore, we aimed to explore the therapeutic potential of MSCs in myocardial fibrosis and its underlying mechanism in vivo and in vitro.

METHODS

A DCM rat model was induced using a high-fat diet (HFD) combined with a low-dose streptozotocin (STZ) injection. After four infusions of MSCs, rat serum and heart tissues were collected, and the levels of blood glucose and lipid, cardiac structure, and function, and the degree of myocardial fibrosis including the expression levels of pro-fibrotic factor and collagen were analyzed using biochemical methods, echocardiography, histopathology, polymerase chain reaction (PCR), and enzyme-linked immunosorbent assay (ELISA). We infused prostaglandin E2 (PGE2)-deficient MSCs to DCM rats in vivo and established a system mimicking diabetic myocardial fibrosis in vitro by inducing cardiac fibroblasts with high glucose (HG) and coculturing them with MSCs or PGE2-deficient MSCs to further explore the underlying mechanism of amelioration of myocardial fibrosis by MSCs.

RESULTS

Metabolic abnormalities, myocardial fibrosis, and cardiac dysfunction in DCM rats were significantly ameliorated after treatment with MSCs. Moreover, the levels of TGF-β, collagen I, collagen III, and collagen accumulation were markedly decreased after MSC infusion compared to those in DCM hearts. However, PGE2-deficient MSCs had decreased ability to alleviate cardiac fibrosis and dysfunction. In addition, in vitro study revealed that the concentration of PGE2 in the MSC group was enhanced, while the proliferation and collagen secretion of cardiac fibroblasts were reduced after MSC treatment. However, MSCs had little effect on alleviating fibrosis when the fibroblasts were pretreated with cyclooxygenase-2 (COX-2) inhibitors, which also inhibited PGE2 secretion. This phenomenon could be reversed by adding PGE2.

CONCLUSIONS

Our results indicated that MSC infusion could ameliorate cardiac fibrosis and dysfunction in DCM rats. The underlying mechanisms might involve the function of PGE2 secreted by MSCs.

Exercise modulates heat shock protein 27 activity in diabetic cardiomyopathy

AIMS

Heat shock protein 27 regulates homeostasis of skeletal and cardiac muscle proteins in various stressful states including diabetes and exercise. Aerobic exercise can inhibit or ameliorate cardiac structural abnormality and dysfunction in diabetic cardiomyopathy. The aim of this study was to evaluate the role of HSP27 in aerobic exercise improving cardiac diastolic dysfunction in type 2 diabetic rats.

METHODS

Forty male Sprague-Dawley rats were randomly divided into the following groups: control, control + aerobic exercise, diabetic, and diabetic + aerobic exercise. Diabetes was induced by feeding with a high-fat high-sugar diet for 7-weeks followed by a single intraperitoneal injection of streptozotocin (30 mg/kg) in male rats. Moderate aerobic exercise training was performed on a treadmill for 8 weeks after induction of diabetes.

KEY FINDINGS

Aerobic exercise increased left ventricular end-diastolic internal diameter, left ventricular end-diastolic volume, myocardial HSP27 protein expression, HSP27-S82 phosphorylation levels, pHSP27-titin binding and improved cardiac muscle fibre alignment in diabetic rats.

SIGNIFICANCE

Our study indicates that moderate aerobic exercise increases HSP27 activation, improves cardiomyocyte fibre alignment and restores cardiac diastolic function.

Mesenchymal stem cells promote type 2 macrophage polarization to ameliorate the myocardial injury caused by diabetic cardiomyopathy

BACKGROUND

Diabetic cardiomyopathy (DCM) is a common complication of diabetes and is characterized by chronic myocardial inflammation. Mesenchymal stem cell (MSC) infusions have recently been suggested to alleviate myocardial injury and ameliorate cardiac function. However, few studies have focused on the effects of MSCs in DCM. Therefore, we explored the effects of MSC-regulated macrophage polarization on myocardial repair in DCM.

METHODS

A DCM rat model was induced by a high-fat diet and streptozotocin (STZ) administration and infused 4 times with MSCs. Rat blood and heart tissue were analyzed for blood glucose levels, lipid levels, echocardiography, histopathology, macrophage phenotype ratios and inflammatory cytokines, respectively. We mimicked chronic inflammation in vitro by inducing peritoneal macrophages with high glucose and LPS, then cocultured these macrophages with MSCs to explore the specific mechanism of MSCs on macrophage polarization.

RESULTS

DCM rats exhibited abnormal blood glucose levels and lipid metabolism, cardiac inflammation and dysfunction. MSC infusion ameliorated metabolic abnormalities and preserved cardiac structure and function in DCM rats. Moreover, MSC infusion significantly increased the M2 phenotype macrophages and alleviated cardiac inflammation. Interestingly, this in vitro study revealed that the MSCs pretreated with a COX-2 inhibitor had little effect on M2 macrophage polarization, but this phenomenon could be reversed by adding prostaglandin E2 (PGE2).

CONCLUSIONS

Our results suggested that MSC infusions can protect against cardiac injury in DCM rats. The underlying mechanisms may include MSC-enhanced M2 macrophage polarization via the COX-2-PGE2 pathway.

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.

Elevated Glycemic Gap Predicts Acute Respiratory Failure and In-hospital Mortality in Acute Heart Failure Patients with Diabetes

Diabetes is a common comorbidity in patients hospitalized for acute heart failure (AHF), but the relationship between admission glucose level, glycemic gap, and in-hospital mortality in patients with both conditions has not been investigated thoroughly. Clinical data for admission glucose, glycemic gap and in-hospital death in 425 diabetic patients hospitalized because of AHF were collected retrospectively. Glycemic gap was calculated as the A1c-derived average glucose subtracted from the admission plasma glucose level. Receiver operating characteristic (ROC) curves were used to determine the optimal cutoff value for glycemic gap to predict all-cause mortality. Patients with glycemic gap levels >43 mg/dL had higher rates of all-cause death (adjusted hazard ratio, 7.225, 95% confidence interval, 1.355-38.520) than those with glycemic gap levels ≤43 mg/dL. The B-type natriuretic peptide levels incorporated with glycemic gap could increase the predictive capacity for in-hospital mortality and increase the area under the ROC from 0.764 to 0.805 (net reclassification improvement = 9.9%, p < 0.05). In conclusion, glycemic gap may be considered a useful parameter for predicting the disease severity and prognosis of patients with diabetes hospitalized for AHF.

Changes in Titin and Collagen Modulate Effects of Aerobic and Resistance Exercise on Diabetic Cardiac Function

Diastolic dysfunction is a common complication that occurs early in diabetes mellitus. Titin and collagen are two important regulators of myocardial passive tension, which contributes to diabetic myocardial diastolic dysfunction. Exercise therapy significantly improves the impaired diabetic cardiac function, but its benefits appear to depend on the type of exercise used. We investigated the effect of aerobic and resistance exercise on cardiac diastolic function in diabetic rats induced by high-fat diet combined with low-dose streptozotocin injection. Interestingly, although resistance training had a more pronounced effect on blood glucose control than did aerobic training in type 2 diabetic rats, improvements in cardiac diastolic parameters benefited more from aerobic training. Moreover, aerobic exercise did significantly increase the expression levels of titin and decrease collagen I, TGFβ1 expression level. In summary, out data suggest that aerobic exercise may improve diabetic cardiac function through changes in titin-dependent myocardial stiffness rather than collagen-dependent interstitial fibrosis.

Association between cardiovascular autonomic neuropathy and left ventricular hypertrophy in young patients with congenital generalized lipodystrophy

BACKGROUND

Congenital generalized lipodystrophy (CGL) is a rare disorder characterized by the absence of subcutaneous adipose tissue, severe insulin resistance, diabetes mellitus, and cardiovascular complications, including cardiac autonomic neuropathy (CAN), left ventricular hypertrophy (LVH), and atherosclerosis. The present study aimed to access the association between CAN parameters and cardiovascular abnormalities in CGL patients.

METHODS

A cross-sectional study was conducted with 10 CGL patients and 20 healthy controls matched for age, sex, BMI, and pubertal stage. We evaluated clinical, laboratory, and cardiovascular parameters-left ventricular mass index (LVMI), interventricular septum thickness (IVS), systolic and diastolic function determined by two-dimensional transthoracic echocardiography; carotid intimal media thickness (cIMT); and cQT interval. Heart rate variability (HRV) was evaluated by spectral analysis components-high frequency (HF), low frequency (LF), very low frequency (VLF), LF/HF ratio, and total amplitude spectrum (TAS)-and cardiovascular reflexes tests (postural hypotension test, respiratory, orthostatic and Valsalva coefficients).

RESULTS

In CGL group, four patients (40%) had LVH and diastolic dysfunction. HF component (parasympathetic control) was lower in LVH patients. CGL patients presented higher values of cIMT and cQT interval than heathy subjects. Inverse association between LVMI and LF (p = 0.011), IVS and LF (p = 0.007), and cIMT and leptin (p < 0.001) were observed, even after adjustments by HOMA-IR, A1c, and blood pressure. In CGL group, there were associations between LMVI and HF component (IC95%: - 1.000; - 00.553), LVMI and TAS (IC95%: - 1.000; - 0.012), and IVS and HF component (IC95%: - 1.000; - 0.371).

CONCLUSION

The association between increased LV mass and parameters of HRV provides possible speculations about the involvement of CAN in the pathophysiology of the cardiac complications, including LVH, in patients with CGL.

Cardioprotective effects of a ruthenium (II) Schiff base complex in diet-induced prediabetic rats

BACKGROUND

Prediabetes and the onset of cardiovascular diseases (CVD) are strongly related. Prolonged hyperglycemia has been identified as a major contributing factor in the pathogenesis of CVD and diabetic complications. The management of hyperglycemia and prediabetes-associated vascular complications rely on pharmacotherapy and lifestyle intervention strategies. However, patients still take the conventional drugs and neglect lifestyle intervention; therefore, newer alternative drugs are required. The synthesized ruthenium Schiff base complex has been shown to have elevated biological and antidiabetic activity. Thus, the research investigated the cardio-protective effects of ruthenium (II) Schiff base complex in diet-induced prediabetic (PD) rats.

MATERIALS AND METHODS

The rats were randomly allocated to respective groups and treated for 12 weeks. Ruthenium (15 mg/kg) was administered to PD rats once a day every third day. Blood pressure and plasma glucose were monitored throughout the study. Blood and heart tissue were collected for biochemical assays.

RESULTS

Ruthenium complex with dietary intervention lead to reduced mean arterial blood pressure which correlated with a restored heart to body weight ratio. Additionally, there was a significant decrease in tissue malondialdehyde and increased superoxide dismutase and glutathione peroxidase concentration in both the plasma and heart tissue. Furthermore, there was a decrease in plasma triglycerides, low-density lipoprotein with an increased high-density lipoprotein concentration in ruthenium-treated rats. This was further evidenced by reduced plasma tumor necrosis factor-α, IL-6, and cardiac C-reactive protein concentrations in ruthenium-treated rats.

CONCLUSION

Ruthenium coupled with dietary intervention decreased the risk of developing cardiac injury, thus preventing CVD in prediabetes. Therefore, this complex may be a beneficial therapeutic agent in the prevention of PD cardiovascular complications.

Pathophysiological mechanisms of diabetic cardiomyopathy and the therapeutic potential of epigallocatechin-3-gallate

Cardiovascular complications are considered one of the leading causes of morbidity and mortality among diabetic patients. Diabetic cardiomyopathy (DCM) is a type of cardiovascular damage presents in diabetic patients independent of the coexistence of ischemic heart disease or hypertension. It is characterized by impaired diastolic relaxation time, myocardial dilatation and hypertrophy and reduced systolic and diastolic functions of the left ventricle. Molecular mechanisms underlying these pathological changes in the diabetic heart are most likely multifactorial and include, but not limited to, oxidative/nitrosative stress, increased advanced glycation end products, mitochondrial dysfunction, inflammation and cell death. The aim of this review is to address the major molecular mechanisms implicated in the pathogenesis of DCM. In addition, this review provides studies conducted to determine the pharmacological effects of (-)-epigallocatechin-3-gallate (EGCG), the major polyphenol in green tea, focusing on its therapeutic potential against the processes involved in the pathogenesis and progression of DCM. EGCG has been shown to exert several potential therapeutic properties both in vitro and in vivo. Given its therapeutic potential, EGCG might be a promising drug candidate to decrease the morbidity and mortality associated with DCM and other diabetes complications.

Western diet given to healthy rats mimics the human phenotype of diabetic cardiomyopathy

Diabetes mellitus (DM) is a major problem worldwide. Within this patient group, cardiovascular diseases are the biggest cause of morbidity and mortality. Diabetic cardiomyopathy (DCM) is defined as diabetes-associated structural and functional changes in the myocardium, not directly attributable to other confounding factors such as coronary artery disease or hypertension. Pathophysiology of DCM remains unclear due to a lack of adequate animal models reflecting the current pandemic of diabetes, associated with a high increased sugar intake and the 'Western' lifestyle. The aim of this study was to develop an animal model mimicking this 'Western' lifestyle causing a human-like phenotype of DCM. Twenty-four Sprague-Dawley rats were randomly assigned into a normal or a 'Western' diet group for 18 weeks. Glucose and insulin levels were measured with an OGTT. Heart function was assessed by echocardiography and hemodynamic measurements in vivo. Cardiac fibrosis and inflammation were investigated in vitro. 'Western' diet given to healthy rats for 18 weeks induced hyperglycemia together with increased AGEs levels, insulin levels and hypertriglyceridemia. Heart function was altered with increased end-diastolic pressure, left ventricle hypertrophy. Changes in vivo were associated with increased collagen deposition and increased PAI-1 levels in the heart. High-sugar diet or 'Western' diet causes T2DM and the hallmarks of DCM in rats, reflecting the phenotype of the disease seen in patients. Using this new model of T2DM with DCM might open new insight in understanding the pathophysiology of DCM and on a long term, test targeted therapies for T2DM with DCM patients.

Supplementation of Type 1 Diabetic Rats with Carrot Powder Lowers Blood Glucose without Improving Cardiac Structure and Function

Foods and food bioactives have shown to be effective in preventing some human disease conditions. In this study, we examined the effects of carrot powder, rich in carotenoids, as a dietary supplement for the prevention of cardiac anomalies in streptozotocin (STZ) induced type 1 diabetic rats. Male Wistar rats were fed either control or carrot powder containing diet for 3 weeks. Type 1 diabetes was induced with STZ injection (65 mg/kg body weight) in half of the rats in each group. All rats were continued on their respective diet for a further 9 weeks. Cardiac structural and functional parameters were measured using echocardiography at 8 weeks post STZ administration. In comparison to non-diabetic rats, diabetic rats showed significant increase in isovolumetric relaxation time and a significant decrease in systolic function parameter, cardiac output. Left ventricular internal dimension and left ventricular posterior wall thickness were significantly higher in diabetic animals. Blood glucose levels were significantly lower in carrot supplemented diabetic rats when compared with non-treated diabetic rats. Diabetic rats treated and untreated had elevated level of lipid peroxidation. Catalase levels were significantly elevated in the carrot powder supplemented diabetic rats when compared to the control rats. Carrot supplementation lowered blood glucose levels significantly but did not normalize it to control levels. It had no effect on cardiac abnormalities and anti-oxidant status in rats with type 1 diabetes.

Resveratrol Prevents Diabetic Cardiomyopathy by Increasing Nrf2 Expression and Transcriptional Activity

OBJECTIVE

This study investigated if resveratrol ameliorates diabetic cardiomyopathy by targeting associated oxidative stress mechanisms.

METHOD

Type 1 diabetes mellitus (DM) in FVB mice was induced by several intraperitoneal injections of a low dose of streptozotocin. Hyperglycemic and age-matched control mice were given resveratrol (10 mg/kg per day) for 1 month and subsequently monitored for an additional 6 months. Mice were assigned to four groups: control, resveratrol, DM, and DM/resveratrol. Cardiac function and blood pressure were assessed at 1, 3, and 6 months after DM induction. Oxidative damage and cardiac fibrosis were analyzed by histopathology, real-time PCR, and Western blot.

RESULT

Mice in the DM group exhibited increased blood glucose levels, cardiac dysfunction, and high blood pressure at 1, 3, and 6 months after DM induction. Resveratrol did not significantly affect blood glucose levels and blood pressure; however, resveratrol attenuated cardiac dysfunction and hypertrophy in DM mice. Resveratrol also reduced DM-induced fibrosis. In addition, DM mice hearts exhibited increased oxidative damage, as evidenced by elevated accumulation of 3-nitrotyrosine and 4-hydroxynonenal, which were both attenuated by resveratrol. Mechanistically, resveratrol increased NFE2-related factor 2 (Nrf2) expression and transcriptional activity, as well as Nrf2's downstream antioxidative targets.

CONCLUSION

We demonstrated that resveratrol prevents DM-induced cardiomyopathy, in part, by increasing Nrf2 expression and transcriptional activity.

Spironolactone Protects against Diabetic Cardiomyopathy in Streptozotocin-Induced Diabetic Rats

Spironolactone (SPR) has been shown to protect diabetic cardiomyopathy (DCM), but the specific mechanisms are not fully understood. Here, we determined the cardioprotective role of SPR in diabetic mice and further explored the potential mechanisms in both in vivo and in vitro models. Streptozotocin- (STZ-) induced diabetic rats were used as the in vivo model. After the onset of diabetes, rats were treated with either SPR (STZ + SPR) or saline (STZ + NS) for 12 weeks; nondiabetic rats were used as controls (NDCs). In vitro, H9C2 cells were exposed to aldosterone, with or without SPR. Cardiac structure was investigated with transmission electron microscopy and pathological examination; immunohistochemistry was performed to detect nitrotyrosine, collagen-1, TGF-β1, TNF-α, and F4/80 expression; and gene expression of markers for oxidative stress, inflammation, fibrosis, and energy metabolism was detected. Our results suggested that SPR attenuated mitochondrial morphological abnormalities and sarcoplasmic reticulum enlargement in diabetic rats. Compared to the STZ + NS group, cardiac oxidative stress, fibrosis, inflammation, and mitochondrial dysfunction were improved by SPR treatment. Our study showed that SPR had cardioprotective effects in diabetic rats by ameliorating mitochondrial dysfunction and reducing fibrosis, oxidative stress, and inflammation. This study, for the first time, indicates that SPR might be a potential treatment for DCM.

Inhibition of miR-186-5p contributes to high glucose-induced injury in AC16 cardiomyocytes

A growing body of evidence has demonstrated that microRNAs (miRs) have pivotal roles in the pathophysiological development mechanisms of diabetic cardiomyopathy (DCM). Previous studies have demonstrated that miR-186-5p was significantly decreased in DCM. In addition, it has recently been reported that an imbalance of miR-186 is associated with a variety of physiological and pathological processes. Therefore, the present study was designed to investigate the role of miR-186-5p in high glucose (HG)-induced cytotoxicity and apoptosis in AC16 cardiomyocytes. Reverse transcription-polymerase chain reaction was used to demonstrate the significant decrease in the level of miR-186-5p in HG-treated AC16 cells (P<0.05). Subsequently, it was clarified that pre-transfection with miR-186-5p mimic significantly ameliorated the effects of high glucose, which induced a significant decrease in the viability of AC16 cells (P<0.05) and increases in apoptosis, as evidenced by the appearance of apoptotic nucleus and the significant upregulation of apoptosis rate in AC16 cells (P<0.05). In addition, the significantly increased expression of caspase-3 induced by HG (P<0.01) was also reversed by miR-186-5p mimic (P<0.01). Conversely, transfection with miR-186-5p inhibitor significantly reduced the viability of AC16 cells (P<0.05) and promoted apoptosis (P<0.05) as well as the expression of caspase-3 in AC16 cells (P<0.01), indicating the beneficial role of miR-186-5p in the physiological process of HG-induced damage. In conclusion, these results suggest that the distribution of miR-186-5p contributes to HG-induced cytotoxicity and apoptosis in AC16 cardiomyocytes.

Fibroblast growth factor 21 inhibition aggravates cardiac dysfunction in diabetic cardiomyopathy by improving lipid accumulation

Diabetic cardiomyopathy (DCM) is one of the major causes of morbidity and mortality in diabetic patients. Recent studies have demonstrated an increased level of fibroblast growth factor 21 (FGF21) in the plasma of DCM patients, and FGF21 has been proven to be a cardiovascular protector of the heart. The present study aimed to further investigate the pathogenic role of FGF21 in DCM, hypothesizing that a lack of FGF21 may promote the progression of DCM by regulating the lipid metabolism, cardiac hypertrophy and cardiac fibrosis, thus deteriorating the cardiac dysfunction. A total of 44 mice were randomly assigned into the normal (n=6), DCM (n=6), normal + scrambled siRNA (n=6), DCM + scrambled siRNA (n=6), normal + FGF21 siRNA (n=10) and DCM + FGF21 siRNA (n=10) groups. Type 1 diabetes mellitus was induced to mice in the DCM groups by streptozotocin injection, while FGF21 expression was inhibited by FGF21 siRNA. Normal and DCM mice administrated with scrambled siRNA were respectively regarded as the controls for the normal + FGF21 siRNA and DCM + FGF21 siRNA groups. In the DCM group, FGF21 inhibition promoted cardiac hypertrophy and fibrosis, and the expression levels of their indicators, including atrial natriuretic factor, α-skeletal actin, collagen type I and III, and transforming growth factor-β, increased, leading to further decreased cardiac function. In addition, FGF21 inhibition in DCM mice elevated the quantity of lipid droplets and the concentration of heart triglycerides, plasma triglycerides and cholesterol levels, accompanied by downregulation of peroxisome proliferator-activated receptor γ co-activator 1α (PGC-1α) and upregulation of cluster of differentiation (CD)36. Thus, the results indicated that FGF21 inhibition exacerbates the cardiac dysfunction by aggravating the lipid accumulation through regulating the expression levels of PGC-1α and CD36. In conclusion, it is suggested that FGF21 may be a potentially useful agent in the treatment of DCM.

Circulating miR-19b and miR-181b are potential biomarkers for diabetic cardiomyopathy

Diabetic cardiomyopathy is characterized by metabolic changes in the myocardium that promote a slow and silent dysfunction of muscle fibers, leading to myocardium remodelling and heart failure, independently of the presence of coronary artery diseases or hypertension. At present, no imaging methods allow an early diagnosis of this disease. Circulating miRNAs in plasma have been proposed as biomarkers in the prognosis of several cardiac diseases. This study aimed to determine whether circulating miRNAs could be potential biomarkers of diabetic cardiomyopathy. Mice that were fed with a high fat diet for 16 months, showed metabolic syndrome manifestations, cardiac hypertrophy (without hypertension) and a progressive cardiac function decline. At 16 months, when maximal degree of cardiac dysfunction was observed, 15 miRNAs from a miRNA microarray screening in myocardium were selected. Then, selected miRNAs expression in myocardium (at 4 and 16 months) and plasma (at 4, 12 and 16 months) were measured by RT-qPCR. Circulating miR-19b-3p and miR-181b-5p levels were associated with myocardium levels during the development of diabetic cardiomyopathy (in terms of cardiac dysfunction), suggesting that these miRNAs could be suitable biomarkers of this disease in asymptomatic diabetic patients.

Left ventricular mass, geometry and function in diabetic patients affected by coronary artery disease

INTRODUCTION

Coronary artery disease (CAD) is quite common among diabetic patients, our study goal is to detect the prevalence of left ventricular (LV) adverse changes in geometry, mass and diastolic function on diabetic, but not hypertensive patients, with coronary artery disease(CAD) and LV ejection fraction(LVEF)>45%, actually unknown, because of current guidelines that do not include echocardiographic assessment for follow up of diabetic patients.

PATIENTS AND METHODS

665 consecutive diabetic patients (443 females, mean age 66±9years), performed a complete echocardiographic assessment according to current ASE echo-guidelines: diastolic dysfunction (DD), eccentric hypertrophy (EH), concentric hypertrophy (CH) and concentric remodeling (CR) of LV were reported. CAD was assessed only by reports of bypass surgery, angioplasty or patients hospitalized for acute myocardial infarction.

RESULTS

218 patients (32.8%) presented LV changes: LVDD 49 (7.4%), LVEH 68 (10.2%), LVDD and EH 46 (6.9%), LVDD and CH 36 (5.4%), LVDD and CR 19 (2.9%). 447 (67.2%) had no LV changes. 81 (12.1%) patients with CAD, presented: LVDD 17 (21%), LVEH 32 (39.5%), LVDD and EH 9 (11.1%), LVDD and CH 7 (8.6%), LVDD and CR 8 (9.9%), 8 (9.9%) had no LV adverse changes. There were among CAD patients, a significantly higher prevalence of LVDD (p<0.02), LV eccentric hypertrophy (EH) (p<0.05), DD and LVEH (p<0.04), DD and LV concentric hypertrophy(CH) (p<0.03) and DD and LV concentric remodeling (p<0.02), when compared with those patients without CAD.

CONCLUSION

CAD is related to all different patterns of LV adverse changes in mass, geometry and diastolic function, with a significantly higher prevalence in our population of diabetic patients with normal systolic function. These changes however remain unrecognized until they undergo to a conventional echocardiographic assessment. We support this tool need to be included into future guidelines concerning follow-up of diabetic patients.

Inhibition of HDAC3 prevents diabetic cardiomyopathy in OVE26 mice via epigenetic regulation of DUSP5-ERK1/2 pathway

Inhibition of total histone deacetylases (HDACs) was phenomenally associated with the prevention of diabetic cardiomyopathy (DCM). However, which specific HDAC plays the key role in DCM remains unclear. The present study was designed to determine whether DCM can be prevented by specific inhibition of HDAC3 and to elucidate the mechanisms by which inhibition of HDAC3 prevents DCM. Type 1 diabetes OVE26 and age-matched wild-type (WT) mice were given the selective HDAC3 inhibitor RGFP966 or vehicle for 3 months. These mice were then killed immediately or 3 months later for cardiac function and pathological examination. HDAC3 activity was significantly increased in the heart of diabetic mice. Administration of RGFP966 significantly prevented DCM, as evidenced by improved diabetes-induced cardiac dysfunction, hypertrophy, and fibrosis, along with diminished cardiac oxidative stress, inflammation, and insulin resistance, not only in the mice killed immediately or 3 months later following the 3-month treatment. Furthermore, phosphorylated extracellular signal-regulated kinases (ERK) 1/2, a well-known initiator of cardiac hypertrophy, was significantly increased, while dual specificity phosphatase 5 (DUSP5), an ERK1/2 nuclear phosphatase, was substantially decreased in diabetic hearts. Both of these changes were prevented by RGFP966. Chromatin immunoprecipitation (ChIP) assay showed that HDAC3 inhibition elevated histone H3 acetylation on the DUSP5 gene promoter at both two time points. These findings suggest that diabetes-activated HDAC3 inhibits DUSP5 expression through deacetylating histone H3 on the primer region of DUSP5 gene, leading to the derepression of ERK1/2 and the initiation of DCM. The present study indicates the potential application of HDAC3 inhibitor for the prevention of DCM.

Pathophysiological Fundamentals of Diabetic Cardiomyopathy

Diabetic cardiomyopathy (DCM) was first recognized more than four decades ago and occurred independent of cardiovascular diseases or hypertension in both type 1 and type 2 diabetic patients. The exact mechanisms underlying this disease remain incompletely understood. Several pathophysiological bases responsible for DCM have been proposed, including the presence of hyperglycemia, nonenzymatic glycosylation of large molecules (e.g., proteins), energy metabolic disturbance, mitochondrial damage and dysfunction, impaired calcium handling, reactive oxygen species formation, inflammation, cardiac cell death, and cardiac hypertrophy and fibrosis, leading to impairment of cardiac contractile functions. Increasing evidence also indicates the phenomenon called "metabolic memory" for diabetes-induced cardiovascular complications, for which epigenetic modulation seemed to play an important role, suggesting that the aforementioned pathogenic bases may be regulated by epigenetic modification. Therefore, this review aims at briefly summarizing the current understanding of the pathophysiological bases for DCM. Although how epigenetic mechanisms play a role remains incompletely understood now, extensive clinical and experimental studies have implicated its importance in regulating the cardiac responses to diabetes, which are believed to shed insight into understanding of the pathophysiological and epigenetic mechanisms for the development of DCM and its possible prevention and/or therapy. © 2017 American Physiological Society. Compr Physiol 7:693-711, 2017.

Role of microRNAs in the pathogenesis of diabetic cardiomyopathy

The morbidity of diabetes mellitus has been increasing annually. As a progressive metabolic disorder, chronic complications occur in the late stage of diabetes. In addition, cardiovascular diseases account for the major cause of morbidity and mortality among the diabetic population worldwide. Diabetic cardiomyopathy (DCM) is a type of diabetic heart disease. Patients with DCM show symptoms and signs of heart failure while no specific cause, such as coronary disease, hypertension, alcohol consumption, or other structural heart diseases has been identified. The pathogenesis of DCM is complex and has not been well understood until recently. MicroRNAs (miRs) belong to a novel family of highly conserved, short, non-coding, single-stranded RNA molecules that regulate transcriptional and post-transcriptional gene expression. Furthermore, recent studies have demonstrated an association between miRs and DCM. In the current review, the role of miRs in the pathogenesis of DCM is summarized. It was concluded that miRs contribute to the regulation of cardiomyocyte hypertrophy, myocardial fibrosis, cardiomyocyte apoptosis, mitochondrial dysfunction, myocardial electrical remodeling, epigenetic modification and various other pathophysiological processes of DCM. These studies may provide novel insights into targets for prevention and treatment of the disease.

Diabetic Cardiomyopathy: Current Approach and Potential Diagnostic and Therapeutic Targets

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

Heart Failure and Chronic Kidney Disease in Type 2 Diabetes

Complex hemodynamic, neurohormonal and biochemical changes occur in heart failure and chronic kidney disease, and hyperglycemia/diabetes further accentuate the multifactorial pathogenetic mechanisms. The acknowledgement of concomitant heart and kidney dysfunction in patients with type 2 diabetes has major clinical implications with regards to prognosis, as they significantly increase the risk of mortality, and to therapeutical strategy of both conditions, as well as of hyperglycemia. A comprehensive interdisciplinary approach is needed in these cases in order to improve the outcomes.

Clinical Update: Cardiovascular Disease in Diabetes Mellitus: Atherosclerotic Cardiovascular Disease and Heart Failure in Type 2 Diabetes Mellitus - Mechanisms, Management, and Clinical Considerations

Cardiovascular disease remains the principal cause of death and disability among patients with diabetes mellitus. Diabetes mellitus exacerbates mechanisms underlying atherosclerosis and heart failure. Unfortunately, these mechanisms are not adequately modulated by therapeutic strategies focusing solely on optimal glycemic control with currently available drugs or approaches. In the setting of multifactorial risk reduction with statins and other lipid-lowering agents, antihypertensive therapies, and antihyperglycemic treatment strategies, cardiovascular complication rates are falling, yet remain higher for patients with diabetes mellitus than for those without. This review considers the mechanisms, history, controversies, new pharmacological agents, and recent evidence for current guidelines for cardiovascular management in the patient with diabetes mellitus to support evidence-based care in the patient with diabetes mellitus and heart disease outside of the acute care setting.

NecroX-5 exerts anti-inflammatory and anti-fibrotic effects via modulation of the TNFα/Dcn/TGFβ1/Smad2 pathway in hypoxia/reoxygenation-treated rat hearts

Inflammatory and fibrotic responses are accelerated during the reperfusion period, and excessive fibrosis and inflammation contribute to cardiac malfunction. NecroX compounds have been shown to protect the liver and heart from ischemia-reperfusion injury. The aim of this study was to further define the role and mechanism of action of NecroX-5 in regulating infl ammation and fi brosis responses in a model of hypoxia/reoxygenation (HR). We utilized HR-treated rat hearts and lipopolysaccharide (LPS)-treated H9C2 culture cells in the presence or absence of NecroX-5 (10 µmol/L) treatment as experimental models. Addition of NecroX-5 signifi cantly increased decorin (Dcn) expression levels in HR-treated hearts. In contrast, expression of transforming growth factor beta 1 (TGFβ1) and Smad2 phosphorylation (pSmad2) was strongly attenuated in NecroX-5-treated hearts. In addition, signifi cantly increased production of tumor necrosis factor alpha (TNFα), TGFβ1, and pSmad2, and markedly decreased Dcn expression levels, were observed in LPS-stimulated H9C2 cells. Interestingly, NecroX-5 supplementation effectively attenuated the increased expression levels of TNFα, TGFβ1, and pSmad2, as well as the decreased expression of Dcn. Thus, our data demonstrate potential antiinflammatory and anti-fibrotic effects of NecroX-5 against cardiac HR injuries via modulation of the TNFα/Dcn/TGFβ1/Smad2 pathway.

Tissue Doppler imaging is a sensitive echocardiographic technique to detect subclinical systolic and diastolic dysfunction of both ventricles in type 1 diabetes mellitus

Background

Subclinical left (LV) and right ventricular (RV) dysfunction has been demonstrated in type 2 diabetes mellitus and evidence indicates impaired LV diastolic function in type 1 diabetes mellitus (T1DM) as well. The aim of our study was to evaluate the role of tissue Doppler imaging (TDI) in assessment of global LV and RV function in T1DM patients.

Methods

A detailed two-dimensional, pulsed wave Doppler and pulsed wave TDI analysis was performed in 53 normotensive middle-aged T1DM patients and compared to healthy controls.

Results

In T1DM patients TDI analysis revealed reduced mean mitral septal and lateral E’ velocities as well as reduced mean tricuspid E˙t velocity compared to healthy controls (E’sept 8.89 ± 1.89 cm/s vs. 11.50 ± 2.41 cm/s, p < 0.001; E’lat 12.29 ± 2.58 cm/s vs.15.30 ± 2.95 cm/s, p < 0,001; E’t 13.56 ± 2.91 cm/s vs. 15.60 ± 2.99 cm/s, p = 0.001). Mean ratios E/E’sept, E/E’lat and E/E’t were significantly higher in diabetics with cutoff value of 7.4 for E/E’sept and 3.4 for E/E’t, differentiating diabetics with LV and RV diastolic impairement from matched healthy controls (sensitivity 76.5 %, specificity 73.8 % for E/E’sept and sensitivity 72.1 %, specificity 66.7 % for E/E’t). Myocardial acceleration during isovolumetric contraction (IVA) measured at the septal mitral (LV IVA) and lateral tricuspid annulus (RV IVA) was the only parameter indicating reduced contractility of both ventricles in diabetics compared to controls (LV IVA 230.70 ± 61.26 cm/s² vs. 283.32 ± 59.74 cm/s², p < 0,001; RV IVA 275.48 ± 68.08 cm/s² vs. 316.86 ± 80.95 cm/s², p = 0.011). LV IVA had better diagnostic accuracy than RV IVA to predict early contractile impairement in T1DM patients (area under the curve 0.758, p < 0.001 for LV IVA and 0.648, p = 0.017 for RV IVA).

Conclusions

TDI is essential to detect subclinical diastolic deterioration of both ventricles in T1DM patients. TDI-derived IVA might be useful to assess early systolic alterations of both ventricles in T1DM patients.