Evidence for cardiomyopathy in familial diabetes mellitus

Local vascular Klotho mediates diabetes-induced atherosclerosis via ERK1/2 and PI3-kinase-dependent signaling pathways

BACKGROUND AND AIMS

Diabetes is one of the major causes of cardiovascular disease (CVD). As high as 29 % of patients with diabetes develop atherosclerosis. Vascular Smooth Muscle Cells (VSMCs) are a key mediator in the pathogenesis of atherosclerosis, generating pro-inflammatory and proliferative characteristics in atherosclerotic lesions.

METHODS

We used human atherosclerotic samples, developed diabetes-induced atherosclerotic mice, and generated loss of function and gain of function in Klotho human aortic smooth muscle cells to investigate the function of Klotho in atherosclerosis.

RESULTS

We found that Klotho expression is decreased in smooth muscle actin-positive cells in patients with diabetes and atherosclerosis. Consistent with human data, we found that Apoe knockout mice with streptozotocin-induced diabetes fed on a high-fat diet showed decreased expression of Klotho in SMCs. Additionally, these mice showed increased expression of TGF-β, MMP9, phosphorylation of ERK and Akt. Further, we utilized primary Human Aortic Smooth Muscle Cells (HASMCs) with d-glucose under dose-response and in time-dependent conditions to study the role of Klotho in these cells. Klotho gain of function and loss of function studies showed that Klotho inversely regulated the expression of atherosclerotic markers TGF-β, MMP2, MMP9, and Fractalkine. Further, High Glucose (HG) induced Akt, and ERK1/2 phosphorylation were enhanced or mitigated by endogenous Klotho deficiency or its overexpression respectively. PI3K/Akt and MAPK/ERK inhibition partially abolished the HG-induced upregulation of TGF-β, MMP2, MMP9, and Fractalkine. Additionally, Klotho knockdown increased the proliferation of HASMCs and enhanced α-SMA and TGF-β expression.

CONCLUSIONS

Taken together, these results indicate that local vascular Klotho is involved in diabetes-induced atherosclerosis, which is via PI3K/Akt and ERK1/2-dependent signaling pathways.

Extracellular Vesicles in Diabetic Cardiomyopathy-State of the Art and Future Perspectives

Cardiovascular complications are the most deadly and cost-driving effects of diabetes mellitus (DM). One of them, which is steadily attracting attention among scientists, is diabetes-induced heart failure, also known as diabetic cardiomyopathy (DCM). Despite significant progress in the research concerning the disease, a universally accepted definition is still lacking. The pathophysiology of the processes accelerating heart insufficiency in diabetic patients on molecular and cellular levels also remains elusive. However, the recent interest concerning extracellular vesicles (EVs) has brought promise to further clarifying the pathological events that lead to DCM. In this review, we sum up recent investigations on the involvement of EVs in DCM and show their therapeutic and indicatory potential.

Pathophysiology and Advances in the Therapy of Cardiomyopathy in Patients with Diabetes Mellitus

Diabetes mellitus (DM) is known as the first non-communicable global epidemic. It is estimated that 537 million people have DM, but the condition has been properly diagnosed in less than half of these patients. Despite numerous preventive measures, the number of DM cases is steadily increasing. The state of chronic hyperglycaemia in the body leads to numerous complications, including diabetic cardiomyopathy (DCM). A number of pathophysiological mechanisms are behind the development and progression of cardiomyopathy, including increased oxidative stress, chronic inflammation, increased synthesis of advanced glycation products and overexpression of the biosynthetic pathway of certain compounds, such as hexosamine. There is extensive research on the treatment of DCM, and there are a number of therapies that can stop the development of this complication. Among the compounds used to treat DCM are antiglycaemic drugs, hypoglycaemic drugs and drugs used to treat myocardial failure. An important element in combating DCM that should be kept in mind is a healthy lifestyle-a well-balanced diet and physical activity. There is also a group of compounds-including coenzyme Q10, antioxidants and modulators of signalling pathways and inflammatory processes, among others-that are being researched continuously, and their introduction into routine therapies is likely to result in greater control and more effective treatment of DM in the future. This paper summarises the latest recommendations for lifestyle and pharmacological treatment of cardiomyopathy in patients with DM.

Single-cell insights: pioneering an integrated atlas of chromatin accessibility and transcriptomic landscapes in diabetic cardiomyopathy

BACKGROUND

Diabetic cardiomyopathy (DCM) poses a growing health threat, elevating heart failure risk in diabetic individuals. Understanding DCM is crucial, with fibroblasts and endothelial cells playing pivotal roles in driving myocardial fibrosis and contributing to cardiac dysfunction. Advances in Multimodal single-cell profiling, such as scRNA-seq and scATAC-seq, provide deeper insights into DCM's unique cell states and molecular landscape for targeted therapeutic interventions.

METHODS

Single-cell RNA and ATAC data from 10x Multiome libraries were processed using Cell Ranger ARC v2.0.1. Gene expression and ATAC data underwent Seurat and Signac filtration. Differential gene expression and accessible chromatin regions were identified. Transcription factor activity was estimated with chromVAR, and Cis-coaccessibility networks were calculated using Cicero. Coaccessibility connections were compared to the GeneHancer database. Gene Ontology analysis, biological process scoring, cell-cell communication analysis, and gene-motif correlation was performed to reveal intricate molecular changes. Immunofluorescent staining utilized various antibodies on paraffin-embedded tissues to verify the findings.

RESULTS

This study integrated scRNA-seq and scATAC-seq data obtained from hearts of WT and DCM mice, elucidating molecular changes at the single-cell level throughout the diabetic cardiomyopathy progression. Robust and accurate clustering analysis of the integrated data revealed altered cell proportions, showcasing decreased endothelial cells and macrophages, coupled with increased fibroblasts and myocardial cells in the DCM group, indicating enhanced fibrosis and endothelial damage. Chromatin accessibility analysis unveiled unique patterns in cell types, with heightened transcriptional activity in myocardial cells. Subpopulation analysis highlighted distinct changes in cardiomyocytes and fibroblasts, emphasizing pathways related to fatty acid metabolism and cardiac contraction. Fibroblast-centered communication analysis identified interactions with endothelial cells, implicating VEGF receptors. Endothelial cell subpopulations exhibited altered gene expressions, emphasizing contraction and growth-related pathways. Candidate regulators, including Tcf21, Arnt, Stat5a, and Stat5b, were identified, suggesting their pivotal roles in DCM development. Immunofluorescence staining validated marker genes of cell subpopulations, confirming PDK4, PPARγ and Tpm1 as markers for metabolic pattern-altered cardiomyocytes, activated fibroblasts and endothelial cells with compromised proliferation.

CONCLUSION

Our integrated scRNA-seq and scATAC-seq analysis unveils intricate cell states and molecular alterations in diabetic cardiomyopathy. Identified cell type-specific changes, transcription factors, and marker genes offer valuable insights. The study sheds light on potential therapeutic targets for DCM.

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

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

Myocardial Calcium Handling in Type 2 Diabetes: A Novel Therapeutic Target

Type 2 diabetes (T2D) is a multisystem disease with rapidly increasing global prevalence. Heart failure has emerged as a major complication of T2D. Dysregulated myocardial calcium handling is evident in the failing heart and this may be a key driver of cardiomyopathy in T2D, but until recently this has only been demonstrated in animal models. In this review, we describe the physiological concepts behind calcium handling within the cardiomyocyte and the application of novel imaging techniques for the quantification of myocardial calcium uptake. We take an in-depth look at the evidence for the impairment of calcium handling in T2D using pre-clinical models as well as in vivo studies, following which we discuss potential novel therapeutic approaches targeting dysregulated myocardial calcium handling in T2D.

Chrysin-based supramolecular cyclodextrin-calixarene drug delivery system: a novel approach for attenuating cardiac fibrosis in chronic diabetes

Introduction: Cardiac fibrosis is strongly induced by diabetic conditions. Both chrysin (CHR) and calixarene OTX008, a specific inhibitor of galectin 1 (Gal-1), seem able to reduce transforming growth factor beta (TGF-β)/SMAD pro-fibrotic pathways, but their use is limited to their low solubility. Therefore, we formulated a dual-action supramolecular system, combining CHR with sulfobutylated β-cyclodextrin (SBECD) and OTX008 (SBECD + OTX + CHR). Here we aimed to test the anti-fibrotic effects of SBECD + OTX + CHR in hyperglycemic H9c2 cardiomyocytes and in a mouse model of chronic diabetes. Methods: H9c2 cardiomyocytes were exposed to normal (NG, 5.5 mM) or high glucose (HG, 33 mM) for 48 h, then treated with SBECD + OTX + CHR (containing OTX008 0.75-1.25-2.5 µM) or the single compounds for 6 days. TGF-β/SMAD pathways, Mitogen-Activated Protein Kinases (MAPKs) and Gal-1 levels were assayed by Enzyme-Linked Immunosorbent Assays (ELISAs) or Real-Time Quantitative Reverse Transcription Polymerase chain reaction (qRT-PCR). Adult CD1 male mice received a single intraperitoneal (i.p.) administration of streptozotocin (STZ) at a dosage of 102 mg/kg body weight. From the second week of diabetes, mice received 2 times/week the following i.p. treatments: OTX (5 mg/kg)-SBECD; OTX (5 mg/kg)-SBECD-CHR, SBECD-CHR, SBECD. After a 22-week period of diabetes, mice were euthanized and cardiac tissue used for tissue staining, ELISA, qRT-PCR aimed to analyse TGF-β/SMAD, extracellular matrix (ECM) components and Gal-1. Results: In H9c2 cells exposed to HG, SBECD + OTX + CHR significantly ameliorated the damaged morphology and reduced TGF-β1, its receptors (TGFβR1 and TGFβR2), SMAD2/4, MAPKs and Gal-1. Accordingly, these markers were reduced also in cardiac tissue from chronic diabetes, in which an amelioration of cardiac remodeling and ECM was evident. In both settings, SBECD + OTX + CHR was the most effective treatment compared to the other ones. Conclusion: The CHR-based supramolecular SBECD-calixarene drug delivery system, by enhancing the solubility and the bioavailability of both CHR and calixarene OTX008, and by combining their effects, showed a strong anti-fibrotic activity in rat cardiomyocytes and in cardiac tissue from mice with chronic diabetes. Also an improved cardiac tissue remodeling was evident. Therefore, new drug delivery system, which could be considered as a novel putative therapeutic strategy for the treatment of diabetes-induced cardiac fibrosis.

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.

Current understanding of structural and molecular changes in diabetic cardiomyopathy

Diabetic Mellitus has been characterized as the most prevalent disease throughout the globe associated with the serious morbidity and mortality of vital organs. Cardiomyopathy is the major leading complication of diabetes and within this, myocardial dysfunction or failure is the leading cause of the emergency hospital admission. The review is aimed to comprehend the perspectives associated with diabetes-induced cardiovascular complications. The data was collected from several electronic databases such as Google Scholar, Science Direct, ACS publication, PubMed, Springer, etc. using the keywords such as diabetes and its associated complication, the prevalence of diabetes, the anatomical and physiological mechanism of diabetes-induced cardiomyopathy, the molecular mechanism of diabetes-induced cardiomyopathy, oxidative stress, and inflammatory stress, etc. The collected scientific data was screened by different experts based on the inclusion and exclusion criteria of the study. This review findings revealed that diabetes is associated with inefficient substrate utilization, inability to increase glucose metabolism and advanced glycation end products within the diabetic heart resulting in mitochondrial uncoupling, glucotoxicity, lipotoxicity, and initially subclinical cardiac dysfunction and finally in overt heart failure. Furthermore, several factors such as hypertension, overexpression of renin angiotensin system, hypertrophic obesity, etc. have been seen as majorly associated with cardiomyopathy. The molecular examination showed biochemical disability and generation of the varieties of free radicals and inflammatory cytokines and becomes are the substantial causes of cardiomyopathy. This review provides a better understanding of the involved pathophysiology and offers an open platform for discussing and targeting therapy in alleviating diabetes-induced early heart failure or cardiomyopathy.

Pericyte Loss in Diseases

Pericytes are specialized cells located in close proximity to endothelial cells within the microvasculature. They play a crucial role in regulating blood flow, stabilizing vessel walls, and maintaining the integrity of the blood-brain barrier. The loss of pericytes has been associated with the development and progression of various diseases, such as diabetes, Alzheimer's disease, sepsis, stroke, and traumatic brain injury. This review examines the detection of pericyte loss in different diseases, explores the methods employed to assess pericyte coverage, and elucidates the potential mechanisms contributing to pericyte loss in these pathological conditions. Additionally, current therapeutic strategies targeting pericytes are discussed, along with potential future interventions aimed at preserving pericyte function and promoting disease mitigation.

The Role of Renin-Angiotensin System in Diabetic Cardiomyopathy: A Narrative Review

Diabetic cardiomyopathy refers to myocardial dysfunction in type 2 diabetes, but without the traditional cardiovascular risk factors or overt clinical atherosclerosis and valvular disease. The activation of the renin-angiotensin system (RAS), oxidative stress, lipotoxicity, maladaptive immune responses, imbalanced mitochondrial dynamics, impaired myocyte autophagy, increased myocyte apoptosis, and fibrosis contribute to diabetic cardiomyopathy. This review summarizes the studies that address the link between cardiomyopathy and the RAS in humans and presents proposed pathophysiological mechanisms underlying this association. The RAS plays an important role in the development and progression of diabetic cardiomyopathy. The over-activation of the classical RAS axis in diabetes leads to the increased production of angiotensin (Ang) II, angiotensin type 1 receptor activation, and aldosterone release, contributing to increased oxidative stress, fibrosis, and cardiac remodeling. In contrast, Ang-(1-7) suppresses oxidative stress, inhibits tissue fibrosis, and prevents extensive cardiac remodeling. Angiotensin-converting-enzyme (ACE) inhibitors and angiotensin receptor blockers improve heart functioning and reduce the occurrence of diabetic cardiomyopathy. Experimental studies also show beneficial effects for Ang-(1-7) and angiotensin-converting enzyme 2 infusion in improving heart functioning and tissue injury. Further research is necessary to fully understand the pathophysiology of diabetic cardiomyopathy and to translate experimental findings into clinical practice.

Does hand stiffness reflect internal organ fibrosis in diabetes mellitus?

Fibrosis leads to irreversible stiffening of tissue and loss of function, and is a common pathway leading to morbidity and mortality in chronic disease. Diabetes mellitus (both type 1 and type 2 diabetes) are associated with significant fibrosis in internal organs, chiefly the kidney and heart, but also lung, liver and adipose tissue. Diabetes is also associated with the diabetic cheirarthropathies, a collection of clinical manifestations affecting the hand that include limited joint mobility (LJM), flexor tenosynovitis, Duypuytren disease and carpal tunnel syndrome. Histo-morphologically these are profibrotic conditions affecting various soft tissue components in the hand. We hypothesize that these hand manifestations reflect a systemic profibrotic state, and are potential clinical biomarkers of current or future internal organ fibrosis. Epidemiologically, there is evidence that fibrosis in one organ associates with fibrosis with another; the putative exposures that lead to fibrosis in diabetes (advanced glycation end product deposition, microvascular disease and hypoxia, persistent innate inflammation) are 'systemic'; a common genetic susceptibility to fibrosis has also been hinted at. These data suggest that a subset of the diabetic population is susceptible to multi-organ fibrosis. The hand is an attractive biomarker to clinically detect this susceptibility, owing to its accessibility to physical examination and exposure to repeated mechanical stresses. Testing the hypothesis has a few pre-requisites: being able to measure hand fibrosis in the hand, using clinical scores or imaging based scores, which will facilitate looking for associations with internal organ fibrosis using validated methodologies for each. Longitudinal studies would be essential in delineating fibrosis trajectories in those with hand manifestations. Since therapies reversing fibrosis are few, the onus lies on identification of a susceptible subset for preventative measures. If systematically validated, clinical hand examination could provide a low-cost, universally accessible and easily reproducible screening step in selecting patients for clinical trials for fibrosis in diabetes.

TRPA1 deficiency attenuates cardiac fibrosis via regulating GRK5/NFAT signaling in diabetic rats

BACKGROUND

Transient receptor potential ankyrin 1 (TRPA1) has been linked to the development of various cardiovascular diseases, but its role in diabetic cardiomyopathy is not well understood. This study aimed to investigate the protective effects of TRPA1 deficiency on diabetic cardiomyopathy in rats with streptozotocin-induced diabetes and in neonatal rat cardiac fibroblasts (CFs) exposed to high glucose (HG).

METHODS

Cardiac TRPA1 expression levels were measured in diabetic rats. Cardiac function, remodeling, and fibrosis were analyzed in Sprague-Dawley (SD) rats and TRPA1-deficient rats with diabetic cardiomyopathy. In vitro, fibrosis was measured in CFs exposed to HG. Additionally, 1,8-cineole, a natural inhibitor of TRPA1, was used to treat SD rats with diabetic cardiomyopathy.

RESULTS

TRPA1 expression was increased in the heart tissue of diabetic rats and in CFs treated with HG. TRPA1 deficiency significantly improved cardiac function in diabetic rats, as evidenced by improved echocardiography and reduced cardiac hypertrophy and fibrosis. In vitro, TRPA1 deficiency suppressed the transformation of HG-induced CFs into myofibroblasts. The cardioprotective effect of TRPA1 deficiency was found to inhibit cardiac fibrosis by regulating GRK5/NFAT signaling. Furthermore, inhibition of GRK5/NFAT signaling abolished the promotion of CF transformation into myofibroblasts by TRPA1 activation. Inhibition of TRPA1 activation by 1,8-cineole reduced cardiac dysfunction and remodeling in diabetic rats by regulating GRK5/NFAT signaling.

CONCLUSIONS

TRPA1 deficiency reduced cardiac fibrosis in diabetic rats and inhibited HG-induced CF activation in vitro by regulating GRK5/NFAT signaling. The TRPA1 inhibitor 1,8-cineole may serve as a novel therapeutic agent for the treatment of diabetic cardiomyopathy.

The Role of Cardiac Fibrosis in Diabetic Cardiomyopathy: From Pathophysiology to Clinical Diagnostic Tools

Diabetes mellitus (DM) is a chronic metabolic disorder characterized by hyperglycemia due to inadequate insulin secretion, resistance, or both. The cardiovascular complications of DM are the leading cause of morbidity and mortality in diabetic patients. There are three major types of pathophysiologic cardiac remodeling including coronary artery atherosclerosis, cardiac autonomic neuropathy, and DM cardiomyopathy in patients with DM. DM cardiomyopathy is a distinct cardiomyopathy characterized by myocardial dysfunction in the absence of coronary artery disease, hypertension, and valvular heart disease. Cardiac fibrosis, defined as the excessive deposition of extracellular matrix (ECM) proteins, is a hallmark of DM cardiomyopathy. The pathophysiology of cardiac fibrosis in DM cardiomyopathy is complex and involves multiple cellular and molecular mechanisms. Cardiac fibrosis contributes to the development of heart failure with preserved ejection fraction (HFpEF), which increases mortality and the incidence of hospitalizations. As medical technology advances, the severity of cardiac fibrosis in DM cardiomyopathy can be evaluated by non-invasive imaging modalities such as echocardiography, heart computed tomography (CT), cardiac magnetic resonance imaging (MRI), and nuclear imaging. In this review article, we will discuss the pathophysiology of cardiac fibrosis in DM cardiomyopathy, non-invasive imaging modalities to evaluate the severity of cardiac fibrosis, and therapeutic strategies for DM cardiomyopathy.

Circulating sphingolipids in heart failure

Lack of significant advancements in early detection and treatment of heart failure have precipitated the need for discovery of novel biomarkers and therapeutic targets. Over the past decade, circulating sphingolipids have elicited promising results as biomarkers that premonish adverse cardiac events. Additionally, compelling evidence directly ties sphingolipids to these events in patients with incident heart failure. This review aims to summarize the current literature on circulating sphingolipids in both human cohorts and animal models of heart failure. The goal is to provide direction and focus for future mechanistic studies in heart failure, as well as pave the way for the development of new sphingolipid biomarkers.

Diabetes Induces Cardiac Fibroblast Activation, Promoting a Matrix-Preserving Nonmyofibroblast Phenotype, Without Stimulating Pericyte to Fibroblast Conversion

Background Interstitial and perivascular fibrosis may contribute to diabetes-associated heart failure. Pericytes can convert to fibroblasts under conditions of stress and have been implicated in the pathogenesis of fibrotic diseases. We hypothesized that in diabetic hearts, pericytes may convert to fibroblasts, contributing to fibrosis and to the development of diastolic dysfunction. Methods and Results Using pericyte:fibroblast dual reporter (NG2^Dsred [neuron-glial antigen 2 red fluorescent protein variant]; PDGFRα^EGFP [platelet-derived growth factor receptor alpha enhanced green fluorescent protein]) mice in a type 2 diabetic db/db background, we found that diabetes does not significantly affect pericyte density but reduces the myocardial pericyte:fibroblast ratio. Lineage tracing using the inducible NG2^CreER driver, along with reliable labeling of fibroblasts with the PDGFRα reporter system, showed no significant pericyte to fibroblast conversion in lean and db/db hearts. In addition, db/db mouse cardiac fibroblasts did not undergo myofibroblast conversion and had no significant induction of structural collagens but exhibited a matrix-preserving phenotype, associated with increased expression of antiproteases, matricellular genes, matrix cross-linking enzymes, and the fibrogenic transcription factor cMyc. In contrast, db/db mouse cardiac pericytes had increased expression of Timp3, without any changes in expression of other fibrosis-associated genes. The matrix-preserving phenotype of diabetic fibroblasts was associated with induction of genes encoding oxidative (Ptgs2/cycloxygenase-2, and Fmo2) and antioxidant proteins (Hmox1, Sod1). In vitro, high glucose partially recapitulated the in vivo changes in diabetic fibroblasts. Conclusions Diabetic fibrosis is not mediated through pericyte to fibroblast conversion but involves acquisition of a matrix-preserving fibroblast program, which is independent of myofibroblast conversion and is only partially explained by the effects of the hyperglycemic environment.

Influence of Flavonoid-Rich Fraction of Monodora tenuifolia Seed Extract on Blood Biochemical Parameters in Streptozotocin-Induced Diabetes Mellitus in Male Wistar Rats

Diabetes mellitus is a metabolic disorder caused by either the total destruction of the pancreatic beta cells that secrete insulin for the uptake of glucose from the circulation or as a result of the inability of body cells to respond to the presence of insulin in the blood. The present study investigated the effect of a flavonoid-rich fraction of Monodora tenuifolia seed extract (FFMTSE) on blood parameters in streptozotocin (STZ)-induced diabetic male Wistar rats. The rats were divided into seven groups (n = 6). Group 1: normal control rats, Group 2: rats + FFMTSE (25 mg/kgbwt), Group 3: rats + FFMTSE (50 mg/kgbwt), Group 4: diabetic control rats, Group 5: diabetic rats + FFMTSE (25 mg/kgbwt), Group 6: diabetic rats + FFMTSE (50 mg/kgbwt), and Group 7: diabetic rats + Metformin. The assessment of the lipid profile, kidney functions (urea and creatinine), and cardiac biomarkers (LDH and CK-MB) were carried out in the plasma using established protocols. The results showed a significant increase in the concentrations of triacylglycerol, cholesterol, LDL-cholesterol, VLDL-cholesterol, urea, and creatinine, as well as in cardiac enzyme activities in diabetic rats. However, the administration of the FFMTSE significantly improved the observed biochemical parameters. In addition, an increased concentration of HDL-cholesterol concentration was observed in the diabetic rats upon treatment with FFMTSE. These findings indicate that FFMTSE could be a potent anti-nephropathy and anti-cardiomyopathy agent in diabetic conditions.

A high-sucrose diet exacerbates the left ventricular phenotype in a high fat-fed streptozotocin rat model of diabetic cardiomyopathy

Left ventricular (LV) dysfunction is an early, clinically detectable sign of cardiomyopathy in type 2 diabetes mellitus (T2DM) that precedes the development of symptomatic heart failure. Preclinical models of diabetic cardiomyopathy are essential to develop therapies that may prevent or delay the progression of heart failure. This study examined the molecular, structural, and functional cardiac phenotype of two rat models of T2DM induced by a high-fat diet (HFD) with a moderate- or high-sucrose content (containing 88.9 or 346 g/kg sucrose, respectively), plus administration of low-dose streptozotocin (STZ). At 8 wk of age, male Sprague-Dawley rats commenced a moderate- or high-sucrose HFD. Two weeks later, rats received low-dose STZ (35 mg/kg ip for 2 days) and remained on their respective diets. LV function was assessed by echocardiography 1 wk before end point. At 22 wk of age, blood and tissues were collected postmortem. Relative to chow-fed sham rats, diabetic rats on a moderate- or high-sucrose HFD displayed cardiac reactive oxygen species dysregulation, perivascular fibrosis, and impaired LV diastolic function. The diabetes-induced impact on LV adverse remodeling and diastolic dysfunction was more apparent when a high-sucrose HFD was superimposed on STZ. In conclusion, a high-sucrose HFD in combination with low-dose STZ produced a cardiac phenotype that more closely resembled T2DM-induced cardiomyopathy than STZ diabetic rats subjected to a moderate-sucrose HFD.NEW & NOTEWORTHY Left ventricular dysfunction and adverse remodeling were more pronounced in diabetic rats that received low-dose streptozotocin (STZ) and a high-sucrose high-fat diet (HFD) compared with those on a moderate-sucrose HFD in combination with STZ. Our findings highlight the importance of sucrose content in diet composition, particularly in preclinical studies of diabetic cardiomyopathy, and demonstrate that low-dose STZ combined with a high-sucrose HFD is an appropriate rodent model of cardiomyopathy in type 2 diabetes.

Impaired calcium handling mechanisms in atrial trabeculae of diabetic patients

The aim of this study was to investigate cardiomyocyte Ca2+ handling and contractile function in freshly excised human atrial tissue from diabetic and non-diabetic patients undergoing routine surgery. Multicellular trabeculae (283 ± 20 μm in diameter) were dissected from the endocardial surface of freshly obtained right atrial appendage samples from consenting surgical patients. Trabeculae were mounted in a force transducer at optimal length, electrically stimulated to contract, and loaded with fura-2/AM for intracellular Ca2+ measurements. The response to stimulation frequencies encompassing the physiological range was recorded at 37°C. Myofilament Ca2+ sensitivity was assessed from phase plots and high potassium contractures of force against [Ca2+ ]i . Trabeculae from diabetic patients (n = 12) had increased diastolic (resting) [Ca2+ ]i (p = 0.03) and reduced Ca2+ transient amplitude (p = 0.04) when compared to non-diabetic patients (n = 11), with no difference in the Ca2+ transient time course. Diastolic stress was increased (p = 0.008) in trabeculae from diabetic patients, and peak developed stress decreased (p ≤ 0.001), which were not accounted for by reduction in the cardiomyocyte, or contractile protein, content of trabeculae. Trabeculae from diabetic patients also displayed diminished myofilament Ca2+ sensitivity (p = 0.018) compared to non-diabetic patients. Our data provides evidence of impaired calcium handling during excitation-contraction coupling with resulting contractile dysfunction in atrial tissue from patients with type 2 diabetes in comparison to the non-diabetic. This highlights the importance of targeting cardiomyocyte Ca2+ homeostasis in developing more effective treatment options for diabetic heart disease in the future.

Central role of cardiac fibroblasts in myocardial fibrosis of diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM), a main cardiovascular complication of diabetes, can eventually develop into heart failure and affect the prognosis of patients. Myocardial fibrosis is the main factor causing ventricular wall stiffness and heart failure in DCM. Early control of myocardial fibrosis in DCM is of great significance to prevent or postpone the progression of DCM to heart failure. A growing body of evidence suggests that cardiomyocytes, immunocytes, and endothelial cells involve fibrogenic actions, however, cardiac fibroblasts, the main participants in collagen production, are situated in the most central position in cardiac fibrosis. In this review, we systematically elaborate the source and physiological role of myocardial fibroblasts in the context of DCM, and we also discuss the potential action and mechanism of cardiac fibroblasts in promoting fibrosis, so as to provide guidance for formulating strategies for prevention and treatment of cardiac fibrosis in DCM.

N-glycosylation-mediated CD147 accumulation induces cardiac fibrosis in the diabetic heart through ALK5 activation

Emerging evidence has implicated the important role of fibrosis in diabetic cardiomyopathy (DCM), while the underlying mechanism remains unclear. Considering the distinct and overlapping roles of Cluster of Differentiation 147 (CD147) in the pathogenesis of fibrotic diseases, we aim to investigate the role of CD147 in the fibrosis of DCM and explore its underlying mechanism. AAV9-mediated cardiac-specific CD147 silencing attenuated cardiac fibrosis and cardiac function in diabetic mice. CD147 knockdown significantly inhibited high glucose (HG)-induced activation of CFs. Mechanistically, CD147 directly bound to type I transcription growth factor β (TGF-β) receptor I (ALK5), promoting ALK5 activation and endocytosis to induce SMAD2/3 phosphorylation and nuclear translocation. In addition, HG prevented the ubiquitin-proteasome-dependent degradation of CD147 by promoting GNT-V-mediated N-glycosylation. As a result, cardiac-specific CD147 overexpression in control mice mimicked diabetes-induced cardiac fibrosis, aggravating cardiac function. Importantly, CD147 was also upregulated in serum and myocardial specimens from patients with diabetes compared with non-diabetes, accompanied by echocardiographic indices of cardiac dysfunction and excessive collagen deposition. Our study provides the first evidence that CD147 acts as a pivotal factor to promote diabetic cardiac fibrosis, and may contribute to the development of future CD147-based therapeutic strategies for DCM.

Polysulfide Protects Against Diabetic Cardiomyopathy Through Sulfhydration of Peroxisome Proliferator-Activated Receptor-γ and Sirtuin 3

Aims: Diabetic cardiomyopathy (DCM) is characterized by cardiac dysfunction and heart failure. However, the effective therapy for DCM is still lacking. Polysulfide contains chains of sulfur atoms, and accumulative evidence has shown that it actively participates in mammalian physiology or pathophysiology. Nevertheless, the potential effects and mechanisms of polysulfide in DCM need further investigation. In the present study, Na₂S₄, a polysulfide donor, was employed to investigate the therapeutic effects of polysulfide in DCM. Results: Our results showed that Na₂S₄ protected cardiomyocytes against high glucose (HG)-induced cardiomyocyte injury. The pathological changes in DCM including cell death, oxidative stress, mitochondrial dysfunction and cardiac hypertrophy were improved by Na₂S₄ treatment. The left ventricular contractile function in streptozotocin (STZ)-induced diabetic mice was significantly improved by Na₂S₄. Mechanistically, Na₂S₄ upregulated and sulfhydrated peroxisome proliferator-activated receptor-γ (PPARγ) and sirtuin 3 (SIRT-3) in cardiomyocytes. Suppression of PPARγ or SIRT-3 with their specific inhibitors or blockade of sulfhydration abolished the protective effects of Na₂S₄. Moreover, mutations of PPARγ or SIRT-3 at specific cysteines diminished the benefits of Na₂S₄ in HG-challenged cardiomyocytes. Innovation and Conclusion: We demonstrated that Na₂S₄ prevented the development of DCM via sulfhydration of both PPARγ and SIRT-3. Our results imply that polysulfide may be a potential and promising agent to treat DCM. Antioxid. Redox Signal. 38, 1-17.

Mitochondrial quality control mechanisms as molecular targets in diabetic heart

Mitochondrial dysfunction has been regarded as a hallmark of diabetic cardiomyopathy. In addition to their canonical metabolic actions, mitochondria influence various other aspects of cardiomyocyte function, including oxidative stress, iron regulation, metabolic reprogramming, intracellular signaling transduction and cell death. These effects depend on the mitochondrial quality control (MQC) system, which includes mitochondrial dynamics, mitophagy and mitochondrial biogenesis. Mitochondria are not static entities, but dynamic units that undergo fission and fusion cycles to maintain their structural integrity. Increased mitochondrial fission elevates the number of mitochondria within cardiomyocytes, a necessary step for cardiomyocyte metabolism. Enhanced mitochondrial fusion promotes communication and cooperation between pairs of mitochondria, thus facilitating mitochondrial genomic repair and maintenance. On the contrary, erroneous fission or reduced fusion promotes the formation of mitochondrial fragments that contain damaged mitochondrial DNA and exhibit impaired oxidative phosphorylation. Under normal/physiological conditions, injured mitochondria can undergo mitophagy, a degradative process that delivers poorly structured mitochondria to lysosomes. However, defective mitophagy promotes the accumulation of nonfunctional mitochondria, which may induce cardiomyocyte death. A decline in the mitochondrial population due to mitophagy can stimulate mitochondrial biogenesis), which generates new mitochondrial offspring to maintain an adequate mitochondrial number. Energy crises or ATP deficiency also increase mitochondrial biogenesis, because mitochondrial DNA encodes 13 subunits of the electron transport chain (ETC) complexes. Disrupted mitochondrial biogenesis diminishes the mitochondrial mass, accelerates mitochondrial senescence and promotes mitochondrial dysfunction. In this review, we describe the involvement of MQC in the pathogenesis of diabetic cardiomyopathy. Besides, the potential targeted therapies that could be applied to improve MQC during diabetic cardiomyopathy are also discussed and accelerate the development of cardioprotective drugs for diabetic patients.

Integrins in cardiac fibrosis

Cells sense mechanical stress and changes in their matrix environment through the integrins, a family of heterodimeric surface receptors that bind to extracellular matrix ligands and trigger cytoskeletal remodeling, while transducing a wide range of intracellular signals. Integrins have been extensively implicated in regulation of inflammation, repair and fibrosis in many different tissues. This review manuscript discusses the role of integrin-mediated cascades in myocardial fibrosis. In vitro studies have demonstrated that β1 and αv integrins play an important role in fibrogenic conversion of cardiac fibroblast, acting through direct stimulation of FAK/Src cascades, or via accentuation of growth factor signaling. Fibrogenic actions of αv integrins may be mediated, at least in part, through pericellular activation of latent TGF-β stores. In vivo evidence supporting the role of integrin heterodimers in fibrotic cardiac remodeling is limited to associative evidence, and to experiments using pharmacologic inhibitors, or global loss-of-function approaches. Studies documenting in vivo actions of integrins on fibroblasts using cell-specific strategies are lacking. Integrin effects on leukocytes may also contribute to the pathogenesis of fibrotic myocardial responses by mediating recruitment and activation of fibrogenic macrophages. The profile and role of integrins in cardiac fibrosis may be dependent on the underlying pathologic condition. Considering their cell surface localization and the availability of small molecule inhibitors, integrins may be attractive therapeutic targets for patients with heart failure associated with prominent fibrotic remodeling.

Cardiac Fibroblast Activation in Patients Early After Acute Myocardial Infarction: Integration with MR Tissue Characterization and Subsequent Functional Outcome

After acute myocardial infarction (AMI), fibroblast activation protein (FAP) upregulation exceeds the infarct region. We sought further insights into the physiologic relevance by correlating FAP-targeted PET with tissue characteristics from cardiac MRI (CMR) and functional outcome. Methods: Thirty-five patients underwent CMR, perfusion SPECT, and ⁶⁸Ga-FAP inhibitor (FAPI)-46 PET/CT within 11 d after AMI. Infarct size was determined from SPECT by comparison to a reference database. For PET, regional SUVs and isocontour volumes of interest determined the extent of cardiac FAP upregulation (FAP volume). CMR yielded functional parameters, area of injury (late gadolinium enhancement [LGE]) and T1/T2 mapping. Follow-up was available from echocardiography or CMR after 139.5 d (interquartile range, 80.5-188.25 d) (n = 14). Results: The area of FAP upregulation was significantly larger than the SPECT perfusion defect size (58% ± 15% vs. 23% ± 17%, P < 0.001) and infarct area by LGE (28% ± 11%, P < 0.001). FAP volume significantly correlated with CMR parameters at baseline (all P < 0.001): infarct area (r = 0.58), left ventricle (LV) mass (r = 0.69), end-systolic volume (r = 0.62), and end-diastolic volume (r = 0.57). Segmental analysis revealed FAP upregulation in 308 of 496 myocardial segments (62%). Significant LGE was found in only 56% of FAP-positive segments, elevated T1 in 74%, and elevated T2 in 68%. Fourteen percent (44/308) of FAP-positive segments exhibited neither prolonged T1 or T2 nor significant LGE. Of note, FAP volume correlated only weakly with simultaneously measured LV ejection fraction at baseline (r = -0.32, P = 0.07), whereas there was a significant inverse correlation with LV ejection fraction obtained at later follow-up (r = -0.58, P = 0.007). Conclusion: Early after AMI and reperfusion therapy, activation of fibroblasts markedly exceeds the hypoperfused infarct region and involves noninfarcted myocardium. The ⁶⁸Ga-FAPI PET signal does not match regional myocardial tissue characteristics as defined by CMR but is predictive of the evolution of ventricular dysfunction. FAP-targeted imaging may provide a novel biomarker of LV remodeling that is complementary to existing techniques.

Fibroblasts: Immunomodulatory factors in refractory diabetic wound healing

Diabetes is a systemic disease in which patients with diabetes may develop peripheral neuropathy of the lower extremities and peripheral vascular disease due to long-term continuous exposure to high glucose. Delayed wound healing in diabetes is one of the major complications of diabetes. Slow wound healing in diabetic patients is associated with high glucose toxicity. When the condition deteriorates, the patient needs to be amputated, which seriously affects the quality of life and even endangers the life of the patient. In general, the delayed healing of diabetes wound is due to the lack of chemokines, abnormal inflammatory response, lack of angiogenesis and epithelial formation, and fibroblast dysfunction. The incidence of several chronic debilitating conditions is increasing in patients with diabetes, such as chronic renal insufficiency, heart failure, and hepatic insufficiency. Fibrosis is an inappropriate deposition of extracellular matrix (ECM) proteins. It is common in diabetic patients causing organ dysfunction. The fibrotic mechanism of diabetic fibroblasts may involve direct activation of permanent fibroblasts. It may also involve the degeneration of fibers after hyperglycemia stimulates immune cells, vascular cells, or organ-specific parenchymal cells. Numerous studies confirm that fibroblasts play an essential role in treating diabetes and its complications. The primary function of fibroblasts in wound healing is to construct and reshape the ECM. Nowadays, with the widespread use of single-cell RNA sequencing (scRNA-seq), an increasing number of studies have found that fibroblasts have become the critical immune sentinel cells, which can detect not only the activation and regulation of immune response but also the molecular pattern related to the injury. By exploring the heterogeneity and functional changes of fibroblasts in diabetes, the manuscript discusses that fibroblasts may be used as immunomodulatory factors in refractory diabetic wound healing, providing new ideas for the treatment of refractory diabetic wound healing.

Mitochondria-Endoplasmic Reticulum Contacts: The Promising Regulators in Diabetic Cardiomyopathy

Diabetic cardiomyopathy (DCM), as a serious complication of diabetes, causes structural and functional abnormalities of the heart and eventually progresses to heart failure. Currently, there is no specific treatment for DCM. Studies have proved that mitochondrial dysfunction and endoplasmic reticulum (ER) stress are key factors for the development and progression of DCM. The mitochondria-associated ER membranes (MAMs) are a unique domain formed by physical contacts between mitochondria and ER and mediate organelle communication. Under high glucose conditions, changes in the distance and composition of MAMs lead to abnormal intracellular signal transduction, which will affect the physiological function of MAMs, such as alter the Ca²⁺ homeostasis in cardiomyocytes, and lead to mitochondrial dysfunction and abnormal apoptosis. Therefore, the dysfunction of MAMs is closely related to the pathogenesis of DCM. In this review, we summarized the evidence for the role of MAMs in DCM and described that MAMs participated directly or indirectly in the regulation of the pathophysiological process of DCM via the regulation of Ca²⁺ signaling, mitochondrial dynamics, ER stress, autophagy, and inflammation. Finally, we discussed the clinical transformation prospects and technical limitations of MAMs-associated proteins (such as MFN2, FUNDC1, and GSK3β) as potential therapeutic targets for DCM.

Co-administration of hydrogen and metformin exerts cardioprotective effects by inhibiting pyroptosis and fibrosis in diabetic cardiomyopathy

Hydrogen is a novel medical gas with several properties, including anti-oxidative, anti-inflammatory, anti-apoptotic, anti-allergic, and energy metabolism stimulating properties. Hydrogen therapy has been proven effective in the treatment of myocardial ischemia, myocardial infarction, and ischemia-reperfusion injury. Diabetic cardiomyopathy (DCM) is a serious cardiovascular complication of long-term chronic diabetes that is linked to increased heart failure and arrhythmia morbidity. The effect of hydrogen on the pathogenesis of DCM is yet to be determined. Metformin is a well-known pharmacological agent for the treatment of diabetes; however, the application of large doses of the drug is limited by its side effects. Therefore, this highlights the importance of developing novel therapies against DCM. In this regard, we investigated the effect of hydrogen on DCM and the mechanisms that underlie it. Furthermore, we also assessed the efficacy of co-administration of metformin and hydrogen. In this study, we found that hydrogen improved cardiac dysfunction and abnormal morphological structure in streptozotocin-induced diabetic mice. As a mechanism, it was confirmed that hydrogen mediated its action by reducing pyroptosis via inhibition of the AMPK/mTOR/NLRP3 signaling pathway and ameliorating fibrosis via inhibition of the TGF-β1/Smad signaling pathway. Furthermore, our findings suggested that co-administration of hydrogen and metformin shows potent protective effects, as evidenced by increased survival rates, reduced fasting blood glucose, and decreased cell injury when compared to a single application of metformin. In conclusion, our study demonstrated that hydrogen inhalation attenuates DCM by reducing pyroptosis and fibrosis and that hydrogen can be combined with metformin to exhibit a more potent cardioprotective effect in DCM.

Pathophysiology and Treatment of Diabetic Cardiomyopathy and Heart Failure in Patients with Diabetes Mellitus

There is a close relationship between diabetes mellitus and heart failure, and diabetes is an independent risk factor for heart failure. Diabetes and heart failure are linked by not only the complication of ischemic heart disease, but also by metabolic disorders such as glucose toxicity and lipotoxicity based on insulin resistance. Cardiac dysfunction in the absence of coronary artery disease, hypertension, and valvular disease is called diabetic cardiomyopathy. Diabetes-induced hyperglycemia and hyperinsulinemia lead to capillary damage, myocardial fibrosis, and myocardial hypertrophy with mitochondrial dysfunction. Lipotoxicity with extensive fat deposits or lipid droplets is observed on cardiomyocytes. Furthermore, increased oxidative stress and inflammation cause cardiac fibrosis and hypertrophy. Treatment with a sodium glucose cotransporter 2 (SGLT2) inhibitor is currently one of the most effective treatments for heart failure associated with diabetes. However, an effective treatment for lipotoxicity of the myocardium has not yet been established, and the establishment of an effective treatment is needed in the future. This review provides an overview of heart failure in diabetic patients for the clinical practice of clinicians.

Sleeve Gastrectomy-Induced AMPK Activation Attenuates Diabetic Cardiomyopathy by Maintaining Mitochondrial Homeostasis via NR4A1 Suppression in Rats

Diabetic cardiomyopathy (DCM) is characterized by impaired diastolic and systolic myocardial performance and is a major cause of morbidity and mortality in patients with diabetes. Surgical bariatric procedures, such as sleeve gastrectomy (SG), result in remission of type 2 diabetes (T2DM) and have benefits with myocardial function. Maintaining cardiac mitochondrial homeostasis is a promising therapeutic strategy for DCM. However, whether SG surgery affects mitochondrial function and its underlying mechanism remains unclear. This study aimed to investigate the effect of SG surgery on mitochondrial homeostasis and intracellular oxidative stress in rats with DCM. We also examined cellular phenotypes and molecular mechanisms in high glucose and high fat-stimulated myocytes. The rat model of DCM was established by high-fat diet feeding and low-dose streptozotocin injection. We observed a remarkably metabolic benefit of SG, including a reduced body weight, food intake, blood glucose levels, and restored glucose tolerance and insulin sensitivity post-operatively. Also, SG ameliorated the pathological cardiac hypertrophy, myocardial fibrosis and the dysfunction of myocardial contraction and diastole, consequently delayed the progression of DCM. Also, SG restored the mitochondrial dysfunction and fragmentation through the AMPK signaling activation mediated nuclear receptor subfamily 4 group A member 1 (NR4A1)/DRP1 suppression in vivo. H9c2 cardiomyocytes showed that activation of AMPK could reverse the mitochondrial dysfunction somehow. Collectively, our study provided evidence that SG surgery could alleviate mitochondrial dysfunction in DCM. Moreover, AMPK-activated NR4A1/DRP1 repression might act as a significant reason for maintaining mitochondrial homeostasis in the myocardium, thus contributing to morphological and functional alleviation of DCM.

MicroRNAs and their delivery in diabetic fibrosis

The global prevalence of diabetes mellitus was estimated to be 463 million people in 2019 and is predicted to rise to 700 million by 2045. The associated financial and societal costs of this burgeoning epidemic demand an understanding of the pathology of this disease, and its complications, that will inform treatment to enable improved patient outcomes. Nearly two decades after the sequencing of the human genome, the significance of noncoding RNA expression is still being assessed. The family of functional noncoding RNAs known as microRNAs regulates the expression of most genes encoded by the human genome. Altered microRNA expression profiles have been observed both in diabetes and in diabetic complications. These transcripts therefore have significant potential and novelty as targets for therapy, therapeutic agents and biomarkers.

Oxidative Stress Signaling Mediated Pathogenesis of Diabetic Cardiomyopathy

As a serious cardiovascular complication, diabetic cardiomyopathy (DCM) refers to diabetes-related changes in myocardial structure and function, which is obviously different from those cardiomyopathy secondary to hypertension, coronary heart disease, and valvular disease. The clinical features of DCM are left ventricular hypertrophy, myocardial fibrosis, and impaired diastolic function. DCM will lead to cardiac dysfunction, eventually progress to cardiac arrhythmia, heart failure, and sudden cardiac death. At present, the pathogenesis of DCM is complex and not fully elucidated, and oxidative stress (OS), inflammatory response, glucolipid metabolism disorder, etc., are considered as the potential pathophysiological mechanisms. As a consequence, there is no specific and effective treatment for DCM. OS refers to the imbalance between reactive oxygen species (ROS) accumulation and scavenging, oxidation, and antioxidants in vivo, which is widely studied in DCM. Numerous studies have pointed out that regulating the OS signaling pathways and reducing the generation and accumulation of ROS are potential directions for the treatment of DCM. This review summarizes the major OS signaling pathways that are related to the pathogenesis of DCM, providing ideas about further research and therapy.

Cardiac Metabolism and Contractile Function in Mice with Reduced Trans-Endothelial Fatty Acid Transport

The heart is a metabolic omnivore that combusts a considerable amount of energy substrates, mainly long-chain fatty acids (FAs) and others such as glucose, lactate, ketone bodies, and amino acids. There is emerging evidence that muscle-type continuous capillaries comprise the rate-limiting barrier that regulates FA uptake into cardiomyocytes. The transport of FAs across the capillary endothelium is composed of three major steps-the lipolysis of triglyceride on the luminal side of the endothelium, FA uptake by the plasma membrane, and intracellular FA transport by cytosolic proteins. In the heart, impaired trans-endothelial FA (TEFA) transport causes reduced FA uptake, with a compensatory increase in glucose use. In most cases, mice with reduced FA uptake exhibit preserved cardiac function under unstressed conditions. When the workload is increased, however, the total energy supply relative to its demand (estimated with pool size in the tricarboxylic acid (TCA) cycle) is significantly diminished, resulting in contractile dysfunction. The supplementation of alternative fuels, such as medium-chain FAs and ketone bodies, at least partially restores contractile dysfunction, indicating that energy insufficiency due to reduced FA supply is the predominant cause of cardiac dysfunction. Based on recent in vivo findings, this review provides the following information related to TEFA transport: (1) the mechanisms of FA uptake by the heart, including TEFA transport; (2) the molecular mechanisms underlying the induction of genes associated with TEFA transport; (3) in vivo cardiac metabolism and contractile function in mice with reduced TEFA transport under unstressed conditions; and (4) in vivo contractile dysfunction in mice with reduced TEFA transport under diseased conditions, including an increased afterload and streptozotocin-induced diabetes.

Necropsy findings in a cat with diabetes mellitus and heart failure

Case summary

A 7-year-old male neutered domestic shorthair cat, previously diagnosed and treated for diabetes mellitus (DM), subsequently presented in heart failure (HF). Echocardiography revealed biatrial and biventricular dilation with poor myocardial function, and a left atrial-to-aortic ratio of 1.95:1. There was caudal vena cava dilation, hepatomegaly and ascites. The HF was treated with furosemide for 5 weeks, but thereafter the cat presented recumbent and moribund, and was euthanased. Post-mortem findings included dilation of all four cardiac chambers with an increased heart weight. Microscopic examination of the heart revealed mild, predominantly interstitial or perivascular fibrosis throughout most of the myocardium, with small-to-medium-sized foci of replacement fibrosis within the left ventricular free wall and interventricular septum. There was evidence of myocyte degeneration, but myofibre disarray was mild and there was minimal evidence of inflammation.

Relevance and novel information

Cardiac disease is common in cats and while HF is less common, it is a frequent cause of clinical signs and death. DM is a relatively common feline endocrinopathy. This case report describes DM and HF presenting as comorbidities, including detailed ante- and post-mortem findings. The case, and the epidemiology of these conditions, raise the question of whether a form of diabetic cardiomyopathy exists in cats, as it appears to do in humans.

Bone Morphogenetic Protein 7 Gene Delivery Improves Cardiac Structure and Function in a Murine Model of Diabetic Cardiomyopathy

Diabetes is a major contributor to the increasing burden of heart failure prevalence globally, at least in part due to a disease process termed diabetic cardiomyopathy. Diabetic cardiomyopathy is characterised by cardiac structural changes that are caused by chronic exposure to the diabetic milieu. These structural changes are a major cause of left ventricular (LV) wall stiffness and the development of LV dysfunction. In the current study, we investigated the therapeutic potential of a cardiac-targeted bone morphogenetic protein 7 (BMP7) gene therapy, administered once diastolic dysfunction was present, mimicking the timeframe in which clinical management of the cardiomyopathy would likely be desired. Following 18 weeks of untreated diabetes, mice were administered with a single tail-vein injection of recombinant adeno-associated viral vector (AAV), containing the BMP7 gene, or null vector. Our data demonstrated, after 8 weeks of treatment, that rAAV6-BMP7 treatment exerted beneficial effects on LV functional and structural changes. Importantly, diabetes-induced LV dysfunction was significantly attenuated by a single administration of rAAV6-BMP7. This was associated with a reduction in cardiac fibrosis, cardiomyocyte hypertrophy and cardiomyocyte apoptosis. In conclusion, BMP7 gene therapy limited pathological remodelling in the diabetic heart, conferring an improvement in cardiac function. These findings provide insight for the potential development of treatment strategies urgently needed to delay or reverse LV pathological remodelling in the diabetic heart.

Effect of empagliflozin on myocardial structure and function in patients with type 2 diabetes at high cardiovascular risk: the SIMPLE randomized clinical trial

To investigate the effects of 13 weeks treatment with empagliflozin in patients with high-risk type-2 diabetes mellitus on echocardiographic measures of left ventricular (LV) structure and function compared to placebo. A total of 91 patients were randomized to treatment with empagliflozin (25 mg/day, n = 45) or matching placebo (n = 45) for 13 weeks. Left ventricular (LV) mass, volumes and geometry as well as measures of LV systolic and diastolic function were measured using echocardiography at baseline and follow up. Mean LV mass index (LVMi) was reduced by - 11.5 g/m² (95% CI - 56.4; 33.4, p = 0.03) with empagliflozin compared to - 1.4 g/m² (95% CI - 36.5; 33.8, p = 0.63) for placebo. The proportion of patients with LV hypertrophy was reduced by 16.3% (p = 0.04) in the empagliflozin group compared to 1.1% in the placebo group (p = 1.00). The proportion of patients with left atrial volume index > 34 mL/m² was reduced by 20.0% (p = 0.02) with empagliflozin compared to 9.5% for placebo (p = 0.45) and the E/e' ratio decreased (∆-0.8 (1.9) vs. ∆0.5 (2.0), p < 0.01). 13 weeks empagliflozin treatment in patients with type-2 diabetes at high CV risk significantly reduced LV mass, improved LV geometry and improved diastolic function compared to placebo.

The role of hyperglycaemia in the development of diabetic cardiomyopathy

Diabetes mellitus is a metabolic disorder with a chronic hyperglycaemic state. Cardiovascular diseases are the primary cause of mortality in patients with diabetes. Increasing evidence supports the existence of diabetic cardiomyopathy, a cardiac dysfunction with impaired cardiac contraction and relaxation, independent of coronary and/or valvular complications. Diabetic cardiomyopathy can lead to heart failure. Several preclinical and clinical studies have aimed to decipher the underlying mechanisms of diabetic cardiomyopathy. Among all the co-factors, hyperglycaemia seems to play an important role in this pathology. Hyperglycaemia has been shown to alter cardiac metabolism and function through several deleterious mechanisms, such as oxidative stress, inflammation, accumulation of advanced glycated end-products and upregulation of the hexosamine biosynthesis pathway. These mechanisms are responsible for the activation of hypertrophic pathways, epigenetic modifications, mitochondrial dysfunction, cell apoptosis, fibrosis and calcium mishandling, leading to cardiac stiffness, as well as contractile and relaxation dysfunction. This review aims to describe the hyperglycaemic-induced alterations that participate in diabetic cardiomyopathy, and their correlation with the severity of the disease and patient mortality, and to provide an overview of cardiac outcomes of glucose-lowering therapy.

High Glucose Activated Cardiac Fibroblasts by a Disruption of Mitochondria-Associated Membranes

Cardiac fibrosis is evident even in the situation without a significant cardiomyocyte loss in diabetic cardiomyopathy and a high glucose (HG) level independently activates the cardiac fibroblasts (CFs) and promotes cell proliferation. Mitochondrial respiration and glycolysis, which are key for cell proliferation and the mitochondria-associated membranes (MAMs), are critically involved in this process. However, the roles and the underlying mechanism of MAMs in the proliferation of HG-induced CFs are largely unknown. The proliferation and apoptosis of CFs responding to HG treatment were evaluated. The MAMs were quantified, and the mitochondrial respiration and cellular glycolytic levels were determined using the Seahorse XF analyzer. The changes of signal transducer and activator of transcription 3 (STAT3) and mitofusin-2 (MFN2) in responding to HG were also determined, the effects of which on cell proliferation, MAMs, and mitochondrial respiration were assessed. The effects of STAT3 on MFN2 transcription was determined by the dual-luciferase reporter assay (DLRA) and chromatin immunoprecipitation (CHIP). HG-induced CFs proliferation increased the glycolytic levels and adenosine triphosphate (ATP) production, while mitochondrial respiration was inhibited. The MAMs and MFN2 expressions were significantly reduced on the HG treatment, and the restoration of MFN2 expression counteracted the effects of HG on cell proliferation, mitochondrial respiration of the MAMs, glycolytic levels, and ATP production. The mitochondrial STAT3 contents were not changed by HG, but the levels of phosphorylated STAT3 and nuclear STAT3 were increased. The inhibition of STAT3 reversed the reduction of MFN2 levels induced by HG. The DLRA and CHIP directly demonstrated the negative regulation of MFN2 by STAT3 at the transcription levels via interacting with the sequences in the MFN2 promoter region locating at about −400 bp counting from the start site of transcription. The present study demonstrated that the HG independently induced CFs proliferation via promoting STAT3 translocation to the nucleus, which switched the mitochondrial respiration to glycolysis to produce ATP by inhibiting MAMs in an MFN2-depression manner.

Protein O-GlcNAcylation in the heart

O-GlcNAcylation is a ubiquitous post-translational modification that is extremely labile and plays a significant role in physiology, including the heart. Sustained activation of cardiac O-GlcNAcylation is frequently associated with alterations in cellular metabolism, leading to detrimental effects on cardiovascular function. This is particularly true during conditions such as diabetes, hypertension, cardiac remodelling, heart failure and arrhythmogenesis. Paradoxically, transient elevation of cardiac protein O-GlcNAcylation can also exert beneficial effects in the heart. There is compelling evidence to suggest that a complex interaction between O-GlcNAcylation and phosphorylation also exists in the heart. Beyond direct functional consequences on cardiomyocytes, O-GlcNAcylation also acts indirectly by altering the function of transcription factors that affect downstream signalling. This review focuses on the potential cardioprotective role of protein O-GlcNAcylation during ischaemia-reperfusion injury, the deleterious consequences of chronically elevated O-GlcNAc levels, the interplay between O-GlcNAcylation and phosphorylation in the cardiomyocytes and the effects of O-GlcNAcylation on other major non-myocyte cell types in the heart.

Fibrosis of the diabetic heart: Clinical significance, molecular mechanisms, and therapeutic opportunities

In patients with diabetes, myocardial fibrosis may contribute to the pathogenesis of heart failure and arrhythmogenesis, increasing ventricular stiffness and delaying conduction. Diabetic myocardial fibrosis involves effects of hyperglycemia, lipotoxicity and insulin resistance on cardiac fibroblasts, directly resulting in increased matrix secretion, and activation of paracrine signaling in cardiomyocytes, immune and vascular cells, that release fibroblast-activating mediators. Neurohumoral pathways, cytokines, growth factors, oxidative stress, advanced glycation end-products (AGEs), and matricellular proteins have been implicated in diabetic fibrosis; however, the molecular links between the metabolic perturbations and activation of a fibrogenic program remain poorly understood. Although existing therapies using glucose- and lipid-lowering agents and neurohumoral inhibition may act in part by attenuating myocardial collagen deposition, specific therapies targeting the fibrotic response are lacking. This review manuscript discusses the clinical significance, molecular mechanisms and cell biology of diabetic cardiac fibrosis and proposes therapeutic targets that may attenuate the fibrotic response, preventing heart failure progression.

Evaluation of the effects of glycated hemoglobin on cardiac function in patients with short-duration type 2 diabetes mellitus: A cardiovascular magnetic resonance study

AIMS

To investigate the association between glycated hemoglobin (HbA1c) and myocardial dysfunction and to determine whether its association is independent of myocardial perfusion.

METHODS

Sixty-four patients with type 2 diabetes mellitus (T2DM) were recruited. They were divided into groups according to their HbA1c level: the controlled T2DM group (HbA1c < 7%) and uncontrolled T2DM groups (HbA1c ≥ 7%). Meanwhile, 30 age-matched healthy volunteers were included. All patients with T2DM and healthy controls underwent cardiovascular magnetic resonance imaging to evaluate the myocardial mechanics and perfusion parameters.

RESULTS

The circumferential and longitudinal peak strain (PS) (p = 0.009 and 0.002 respectively) and global radial, circumferential, and longitudinal peak strain diastolic strain rates (PDSRs) (p = 0.002, 0.001, and 0.001 respectively) were lower in the uncontrolled T2DM group than in the controls without diabetes. In multivariable linear regression analysis, HbA1c was independently related to all directions of the PS and PDSR. The myocardial perfusion parameters were not independently associated with the PS or PDSR.

CONCLUSIONS

Cardiac function is impaired in Chinese T2DM patients with poor glucose control (HbA1c ≥ 7%), with preserved left ventricular (LV) ejection fraction, and disease duration <10 years. Poor blood glucose control is an independent predictor of LV myocardial dysfunction for patients with short-term T2DM.

Targeting TRAF3IP2 alleviates high glucose-induced cardiomyocyte inflammation and apoptosis

To clarify the role of TRAF3IP2 in high glucose (HG)-stimulated cardiomyocyte inflammation and apoptosis and its action mechanism. SiRNA plasmid of TRAF3IP2 was constructed and transfected into HG-stimulated cardiomyocytes to silence TRAF3IP2. The expression of TRAF3IP2 was determined by quantitative polymerase chain reaction (qPCR) and western blot. Cell viability and cytotoxicity were first observed using cell counting kit-8 and lactate dehydrogenase assays. The inflammatory injury of the cardiomyocytes was then examined by real time-qPCR (RT-qPCR) and western blot. The oxidative stress of the cardiomyocytes was evaluated using reactive oxygen species assay kit, RT-qPCR, western blot and enzyme activity assay kit. Next, cell apoptosis was detected employing TUNEL and western blot. Finally, RT-qPCR and western blot were performed to investigate the effects of inhibitors of dipeptidyl peptidase-4, including saxagliptin, empagliflozin and linagliptin, on TRAF3IP2. TRAF3IP2 expression was found to be increased in HG-stimulated cardiomyocytes. TRAF3IP2 interference inhibited HG-induced cell viability loss, cytotoxicity, inflammatory response, oxidative stress and apoptosis of the cardiomyocytes. Moreover, saxagliptin, empagliflozin and linagliptin inhibited the expression of TRAF3IP2. TRAF3IP2 interference alleviates HG-induced inflammation and apoptosis of cardiomyocytes. The result suggests that TRAF3IP2 may be a promising therapeutic target in treating diabetic cardiomyopathy.

Fructose Metabolism and Cardiac Metabolic Stress

Cardiovascular disease is one of the leading causes of mortality in diabetes. High fructose consumption has been linked with the development of diabetes and cardiovascular disease. Serum and cardiac tissue fructose levels are elevated in diabetic patients, and cardiac production of fructose via the intracellular polyol pathway is upregulated. The question of whether direct myocardial fructose exposure and upregulated fructose metabolism have potential to induce cardiac fructose toxicity in metabolic stress settings arises. Unlike tightly-regulated glucose metabolism, fructose bypasses the rate-limiting glycolytic enzyme, phosphofructokinase, and proceeds through glycolysis in an unregulated manner. In vivo rodent studies have shown that high dietary fructose induces cardiac metabolic stress and functional disturbance. In vitro, studies have demonstrated that cardiomyocytes cultured in high fructose exhibit lipid accumulation, inflammation, hypertrophy and low viability. Intracellular fructose mediates post-translational modification of proteins, and this activity provides an important mechanistic pathway for fructose-related cardiomyocyte signaling and functional effect. Additionally, fructose has been shown to provide a fuel source for the stressed myocardium. Elucidating the mechanisms of fructose toxicity in the heart may have important implications for understanding cardiac pathology in metabolic stress settings.

Tenascin-C in Heart Diseases-The Role of Inflammation

Tenascin-C (TNC) is a large extracellular matrix (ECM) glycoprotein and an original member of the matricellular protein family. TNC is transiently expressed in the heart during embryonic development, but is rarely detected in normal adults; however, its expression is strongly up-regulated with inflammation. Although neither TNC-knockout nor -overexpressing mice show a distinct phenotype, disease models using genetically engineered mice combined with in vitro experiments have revealed multiple significant roles for TNC in responses to injury and myocardial repair, particularly in the regulation of inflammation. In most cases, TNC appears to deteriorate adverse ventricular remodeling by aggravating inflammation/fibrosis. Furthermore, accumulating clinical evidence has shown that high TNC levels predict adverse ventricular remodeling and a poor prognosis in patients with various heart diseases. Since the importance of inflammation has attracted attention in the pathophysiology of heart diseases, this review will focus on the roles of TNC in various types of inflammatory reactions, such as myocardial infarction, hypertensive fibrosis, myocarditis caused by viral infection or autoimmunity, and dilated cardiomyopathy. The utility of TNC as a biomarker for the stratification of myocardial disease conditions and the selection of appropriate therapies will also be discussed from a clinical viewpoint.

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.

A Novel ALDH2 Activator AD-9308 Improves Diastolic and Systolic Myocardial Functions in Streptozotocin-Induced Diabetic Mice

Diabetes mellitus has reached epidemic proportion worldwide. One of the diabetic complications is cardiomyopathy, characterized by early left ventricular (LV) diastolic dysfunction, followed by development of systolic dysfunction and ventricular dilation at a late stage. The pathogenesis is multifactorial, and there is no effective treatment yet. In recent years, 4-hydroxy-2-nonenal (4-HNE), a toxic aldehyde generated from lipid peroxidation, is implicated in the pathogenesis of cardiovascular diseases. Its high bioreactivity toward proteins results in cellular damage. Mitochondrial aldehyde dehydrogenase 2 (ALDH2) is the major enzyme that detoxifies 4-HNE. The development of small-molecule ALDH2 activator provides an opportunity for treating diabetic cardiomyopathy. This study found that AD-9308, a water-soluble andhighly selective ALDH2 activator, can improve LV diastolic and systolic functions, and wall remodeling in streptozotocin-induced diabetic mice. AD-9308 treatment dose-dependently lowered serum 4-HNE levels and 4-HNE protein adducts in cardiac tissue from diabetic mice, accompanied with ameliorated myocardial fibrosis, inflammation, and apoptosis. Improvements of mitochondrial functions, sarco/endoplasmic reticulumcalcium handling and autophagy regulation were also observed in diabetic mice with AD-9308 treatment. In conclusion, ADLH2 activation effectively ameliorated diabetic cardiomyopathy, which may be mediated through detoxification of 4-HNE. Our findings highlighted the therapeutic potential of ALDH2 activation for treating diabetic cardiomyopathy.

Fine-tuning the cardiac O-GlcNAcylation regulatory enzymes governs the functional and structural phenotype of the diabetic heart

AIMS

The glucose-driven enzymatic modification of myocardial proteins by the sugar moiety, β-N-acetylglucosamine (O-GlcNAc), is increased in pre-clinical models of diabetes, implicating protein O-GlcNAc modification in diabetes-induced heart failure. Our aim was to specifically examine cardiac manipulation of the two regulatory enzymes of this process on the cardiac phenotype, in the presence and absence of diabetes, utilising cardiac-targeted recombinant-adeno-associated viral-vector-6 (rAAV6)-mediated gene delivery.

METHODS AND RESULTS

In human myocardium, total protein O-GlcNAc modification was elevated in diabetic relative to non-diabetic patients, and correlated with left ventricular (LV) dysfunction. The impact of rAAV6-delivered O-GlcNAc transferase (rAAV6-OGT, facilitating protein O-GlcNAcylation), O-GlcNAcase (rAAV6-OGA, facilitating de-O-GlcNAcylation) and empty vector (null) were determined in non-diabetic and diabetic mice. In non-diabetic mice, rAAV6-OGT was sufficient to impair LV diastolic function and induce maladaptive cardiac remodelling, including cardiac fibrosis and increased Myh-7 and Nppa pro-hypertrophic gene expression, recapitulating characteristics of diabetic cardiomyopathy. In contrast, rAAV6-OGA (but not rAAV6-OGT) rescued LV diastolic function and adverse cardiac remodelling in diabetic mice. Molecular insights implicated impaired cardiac PI3K(p110α)-Akt signalling as a potential contributing mechanism to the detrimental consequences of rAAV6-OGT in vivo. In contrast, rAAV6-OGA preserved PI3K(p110α)-Akt signalling in diabetic mouse myocardium in vivo and prevented high glucose-induced impairments in mitochondrial respiration in human cardiomyocytes in vitro.

CONCLUSION

Maladaptive protein O-GlcNAc modification is evident in human diabetic myocardium, and is a critical regulator of the diabetic heart phenotype. Selective targeting of cardiac protein O-GlcNAcylation to restore physiological O-GlcNAc balance may represent a novel therapeutic approach for diabetes-induced heart failure.

TRANSLATIONAL PERSPECTIVE

There remains a lack of effective clinical management of diabetes-induced cardiac dysfunction, even via conventional intensive glucose-lowering approaches. Here we reveal that the modification of myocardial proteins by O-GlcNAc, a glucose-driven process, is not only increased in human diabetic myocardium, but correlates with reduced cardiac function in affected patients. Moreover, manipulation of the two regulatory enzymes of this process exert opposing influences on the heart, whereby increasing O-GlcNAc transferase (OGT) is sufficient to replicate the cardiac phenotype of diabetes (in the absence of this disease), while increasing O-GlcNAc-ase (OGA) rescues diabetes-induced impairments in both cardiac dysfunction and remodelling. Cardiac O-GlcNAcylation thus represents a novel therapeutic target for diabetes-induced heart failure.

Review of Insulin Resistance in Dilated Cardiomyopathy and Implications for the Pediatric Patient Short Title: Insulin Resistance DCM and Pediatrics

Energy metabolism in the heart is affected during states of dysfunction. Understanding how the heart utilizes substrates in cardiomyopathy may be key to the development of alternative treatment modalities. Myocardial insulin resistance has been proposed as a possible barrier to effective glucose metabolism in the heart. Extensive literature on the topic in adult individuals exists; however, review in the pediatric population is sparse. The pathophysiology of disease in children and adolescents is unique. The aim of this paper is to review the current knowledge on insulin resistance in dilated cardiomyopathy while also filling the gap when considering care in the pediatric population.

Histone Deacetylases in the Pathogenesis of Diabetic Cardiomyopathy

The global burden of diabetes mellitus and its complications are currently increasing. Diabetic cardiomyopathy (DCM) is the main cause of diabetes mellitus associated morbidity and mortality; therefore, a comprehensive understanding of DCM development is required for more effective treatment. A disorder of epigenetic posttranscriptional modification of histones in chromatin has been reported to be associated with the pathology of DCM. Recent studies have implicated that histone deacetylases could regulate cardiovascular and metabolic diseases in cellular processes including cardiac fibrosis, hypertrophy, oxidative stress and inflammation. Therefore in this review, we summarized the roles of histone deacetylases in the pathogenesis of DCM, aiming to provide insights into exploring potential preventative and therapeutic strategies of DCM.