Molecular Dysfunction and Phenotypic Derangement in Diabetic Cardiomyopathy

Mitochondria fission accentuates oxidative stress in hyperglycemia-induced H9c2 cardiomyoblasts in vitro by regulating fatty acid oxidation

Oxidative stress plays a pivotal role in the development of diabetic cardiomyopathy (DCM). Previous studies have revealed that inhibition of mitochondrial fission suppressed oxidative stress and alleviated mitochondrial dysfunction and cardiac dysfunction in diabetic mice. However, no research has confirmed whether mitochondria fission accentuates hyperglycemia-induced cardiomyoblast oxidative stress through regulating fatty acid oxidation (FAO). We used H9c2 cardiomyoblasts exposed to high glucose (HG) 33 mM to simulate DCM in vitro. Excessive mitochondrial fission, poor cell viability, and lipid accumulation were observed in hyperglycemia-induced H9c2 cardiomyoblasts. Also, the cells were led to oxidative stress injury, lower adenosine triphosphate (ATP) levels, and apoptosis. Dynamin-related protein 1 (Drp1) short interfering RNA (siRNA) decreased targeted marker expression, inhibited mitochondrial fragmentation and lipid accumulation, suppressed oxidative stress, reduced cardiomyoblast apoptosis, and improved cell viability and ATP levels in HG-exposed H9c2 cardiomyoblasts, but not in carnitine palmitoyltransferase 1 (CPT1) inhibitor etomoxir treatment cells. We also found subcellular localization of CPT1 on the mitochondrial membrane, FAO, and levels of nicotinamide adenine dinucleotide phosphate (NADPH) were suppressed after exposure to HG treatment, whereas Drp1 siRNA normalized mitochondrial CPT1, FAO, and NADPH. However, the blockade of FAO with etomoxir abolished the above effects of Drp1 siRNA in hyperglycemia-induced H9c2 cardiomyoblasts. The preservation of mitochondrial function through the Drp1/CPT1/FAO pathway is the potential mechanism of inhibited mitochondria fission in attenuating oxidative stress injury of hyperglycemia-induced H9c2 cardiomyoblasts.

Implication of geriatric nutritional risk index on treatment response and long-term prognosis in patients with cardiac resynchronization therapy

PURPOSE

Geriatric Nutritional Risk Index (GNRI) is a simple tool for assessing the nutritional status of the aging population. This study aims to explore the clinical implication of GNRI on treatment response and long-term clinical outcomes in heart failure (HF) patients receiving cardiac resynchronization therapy (CRT).

METHODS

Patients who underwent CRT implantation or upgrade at our hospital were retrospectively included. The association of GNRI and its tertiles with the echocardiographic response, all-cause mortality or heart transplantation, and the first hospitalization due to HF were investigated.

RESULTS

Totally, 647 patients were enrolled, with a median age of 60 [Interquartile Range (IQR): 52-67] years and mean score of GNRI at 107.9 ± 23.7. Super-response rates increased significantly among the GNRI T1, T2, and T3 groups (25.1%, 29.8% vs. 41.1%, P = 0.002). Patients with higher GNRI were more likely to have better LVEF improvement after multiple adjustments (OR = 1.13, 95% CI: 1.04-1.23, P = 0.010). Higher GNRI was independently associated with a lower risk of all-cause mortality or heart implantation (HR = 0.95, 95% CI: 0.93-0.96, P < 0.001) and HF hospitalization (HR = 0.96, 95% CI: 0.95-0.98, P < 0.001). The inclusion of GNRI enhanced the predictability of all-cause mortality based on traditional model, including sex, New York Heart Association functional class, left bundle branch block, QRS reduction, and N-terminal pro-B-type natriuretic peptide level (C statistics improved from 0.785 to 0.813, P = 0.007).

CONCLUSION

Higher GNRI was associated with better treatment response and long-term prognosis in HF patients with CRT. Evaluation of nutritional status among CRT population is necessary for individualized choice of potential responders.

Role of myocardial microRNAs in the long-term ventricular remodelling of patients with aortic stenosis

Aims

We hypothesize that miRs are key players in the dynamics of the hypertrophy phenotype in aortic stenosis (AS) patients. In our study, we aimed to identify the transcriptional patterns (protein-coding transcripts and miRs) from myocardial sample biopsies that could be associated with the absence of left ventricular (LV) mass regression after aortic valve replacement (AVR) in patients with severe AS and LV hypertrophy.

Methods and results

We prospectively included 40 patients with severe AS, LV hypertrophy, and preserved ejection fraction undergoing AVR. Myocardial biopsies obtained during surgery were analysed for transcriptomic analysis performed by next-generation sequencing. At a 1-year follow-up, no hypertrophy reversal was observed in about half of the patients in the absence of patient-prosthesis mismatch and prosthesis dysfunction of uncontrolled hypertension. Predictors of mass regression were assessed from clinical, echocardiographic, and biochemical variables as well as from 300 miRs obtained from myocardial specimens, allowing the identification 29 differentially expressed. miR-4709-3p was found as a positive independent predictor of hypertrophy regression together with high-sensitivity troponin T (cTNT-hs) as a negative predictor. Gene transcripts RFX1, SIX5, MAPK8IF3, and PKD1 were predicted as simultaneous targets of five upregulated miRs suggesting its importance in LV hypertrophy.

Conclusion

In our cohort, tissue miR-4709-3p and cTNT-hs were independent predictors of hypertrophy regression. The hypertrophy reversal process will likely depend from a complex network where miRNAs may have an important role, allowing a potential opportunity for therapy.

Maladaptive response following glucose overload in GLUT4-overexpressing H9C2 cardiomyoblasts

BACKGROUND

Glucose overload drives diabetic cardiomyopathy by affecting the tricarboxylic acid pathway. However, it is still unknown how cells could overcome massive chronic glucose influx on cellular and structural level.

METHODS/MATERIALS

Expression profiles of hyperglycemic, glucose transporter-4 (GLUT4) overexpressing H9C2 (KE2) cardiomyoblasts loaded with 30 mM glucose (KE230L) and wild type (WT) cardiomyoblasts loaded with 30 mM glucose (WT30L) were compared using proteomics, real-time polymerase quantitative chain reaction analysis, or Western blotting, and immunocytochemistry.

RESULTS

The findings suggest that hyperglycemic insulin-sensitive cells at the onset of diabetic cardiomyopathy present complex changes in levels of structural cell-related proteins like tissue inhibitor of metalloproteases-1 (1.3 fold), intercellular adhesion molecule 1 (1.8 fold), type-IV-collagen (3.2 fold), chaperones (Glucose-Regulated Protein 78: 1.8 fold), autophagy (Autophagosome Proteins LC3A, LC3B: 1.3 fold), and in unfolded protein response (UPR; activating transcription factor 6α expression: 2.3 fold and processing: 2.4 fold). Increased f-actin levels were detectable with glucose overload by immnocytochemistry. Effects on energy balance (1.6 fold), sirtuin expression profile (Sirtuin 1: 0.7 fold, sirtuin 3: 1.9 fold, and sirtuin 6: 4.2 fold), and antioxidant enzymes (Catalase: 0.8 fold and Superoxide dismutase 2: 1.5 fold) were detected.

CONCLUSION

In conclusion, these findings implicate induction of chronic cell distress by sustained glucose accumulation with a non-compensatory repair reaction not preventing final cell death. This might explain the chronic long lasting pathogenesis observed in developing heart failure in diabetes mellitus.

Diabetic Cardiomyopathy-From Basics through Diagnosis to Treatment

Diabetic cardiomyopathy (DCM) is the development of myocardial dysfunction in patients with diabetes despite the absence of comorbidities such as hypertension, atherosclerosis or valvular defect. The cardiovascular complications of poorly controlled diabetes are very well illustrated by the U.K. Prospective Diabetes Study (UKPDS), which showed a clear association between increasing levels of glycated hemoglobin and the development of heart failure (HF). The incidence of HF in patients with diabetes is projected to increase significantly, which is why its proper diagnosis and treatment is so important. Providing appropriate therapy focusing on antidiabetic and hypolipemic treatment with the consideration of pharmacotherapy for heart failure reduces the risk of CMD and reduces the incidence of cardiovascular complications. Health-promoting changes made by patients such as a low-carbohydrate diet, regular exercise and weight reduction also appear to be important in achieving appropriate outcomes. New hope for the development of therapies for DCM is offered by novel methods using stem cells and miRNA, which, however, require more thorough research to confirm their efficacy.

ATP releasing channels and the ameliorative effects of high intensity interval training on diabetic heart: a multifaceted analysis

Type 2 diabetes (T2D) can cause severe cardiac complications at functional, histologic and molecular levels. These pathological complications could be mediated by ATP-releasing channels such as Panx1 and ATP receptors, in particular P2X7. The aim of our study was to investigate the effect of high-intensity interval training (HIIT) on T2D-induced cardiac complications at the functional, histopathological and molecular levels, with a particular focus on ATP-releasing channels. 48 male Wistar rats at the age of 8 weeks were randomly allocated into four groups: control (Con), Diabetes (T2D), Training (TR), and Diabetes + Training (T2D + TR). T2D was induced by a high-fat diet plus a low dose (35 mg/kg) of STZ administration. Rats in the TR and T2D + TR groups underwent an 8-weeks training program involving intervals ranging from 80 to 100% of their maximum running speed (Vmax), with 4-10 intervals per session. Protein expression of Interleukin 1β (IL1β), Interleukin 10 (IL-10), Pannexin 1 (Panx1), P2X7R (purinergic P2X receptor 7), NLRP1 (NLR Family Pyrin Domain Containing 1), BAX, and Bcl2 were measured in the heart tissue. Additionally, we assessed heart function, histopathological changes, as well as insulin resistance using the homeostasis model assessment of insulin resistance (HOMA-IR). In contrast to the T2D group, HIIT led to increased protein expression of Bcl2 and IL-10 in the heart. It also resulted in improvements in systolic and diastolic blood pressures, heart rate, ± dp/dt (maximum and minimum changes in left ventricular pressure), while reducing protein expression of IL-1β, Panx1, P2X7R, NLRP1, and BAX levels in the heart. Furthermore, left ventricular diastolic pressure (LVDP) was reduced (P ≤ 0.05). Moreover, heart lesion scores increased with T2D but decreased with HIIT, along with a reduction in fibrosis percentage (P ≤ 0.05). The results of this study suggest that the cardioprotective effects of HIIT on the diabetic heart may be mediated by the modulation of ATP-releasing channels. This modulation may lead to a reduction in inflammation and apoptosis, improve cardiac function, and attenuate cardiac injury and fibrosis.

Identification of potential biomarkers for diabetic cardiomyopathy using LC-MS-based metabolomics

Diabetic cardiomyopathy (DCM) is a serious complication of type 2 diabetes mellitus (T2DM) that contributes to cardiovascular morbidity and mortality. However, the metabolic alterations and specific biomarkers associated with DCM in T2DM remain unclear. In this study, we conducted a comprehensive metabolomic analysis using liquid chromatography-mass spectrometry (LC-MS) to investigate the plasma metabolite profiles of T2DM patients with and without DCM. We identified significant differences in metabolite levels between the groups, highlighting the dysregulation of various metabolic pathways, including starch and sucrose metabolism, steroid hormone biosynthesis, tryptophan metabolism, purine metabolism, and pyrimidine metabolism. Although several metabolites showed altered abundance in DCM, they also shared characteristics of DCM and T2DM rather than specific to DCM. Additionally, through biomarker analyses, we identified potential biomarkers for DCM, such as cytidine triphosphate, 11-ketoetiocholanolone, saccharopine, nervonic acid, and erucic acid. These biomarkers demonstrated distinct patterns and associations with metabolic pathways related to DCM. Our findings provide insights into the metabolic changes associated with DCM in T2DM patients and highlight potential biomarkers for further validation and clinical application. Further research is needed to elucidate the underlying mechanisms and validate the diagnostic and prognostic value of these biomarkers in larger cohorts.

Hmgcs2 is the hub gene in diabetic cardiomyopathy and is negatively regulated by Hmgcs2, promoting high glucose-induced cardiomyocyte injury

BACKGROUND

Diabetic cardiomyopathy (DCM) represents a major cause of heart failure and a large medical burden worldwide. This study screened the potentially regulatory targets of DCM and analyzed their roles in high glucose (HG)-induced cardiomyocyte injury.

METHODS

Through GEO database, we obtained rat DCM expression chips and screened differentially expressed genes. Rat cardiomyocytes (H9C2) were induced with HG. 3-hydroxy-3-methylglutarylcoenzyme A synthase 2 (Hmgcs2) and microRNA (miR)-363-5p expression patterns in cells were measured by real-time quantitative polymerase chain reaction or Western blot assay, with the dual-luciferase assay to analyze their binding relationship. Then, 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay, lactate dehydrogenase assay, terminal deoxynucleotidyl transferase dUTP nick end labeling assay, enzyme-linked immunosorbent assay, and various assay kits were applied to evaluate cell viability, cytotoxicity, apoptosis, inflammation responses, and oxidative burden.

RESULTS

Hmgcs2 was the vital hub gene in DCM. Hmgcs2 was upregulated in HG-induced cardiomyocytes. Hmgcs2 downregulation increased cell viability, decreased TUNEL-positive cell number, reduced HG-induced inflammation and oxidative stress. miR-363-5p is the upstream miRNA of Hmgcs2. miR-363-5p overexpression attenuated HG-induced cell injury.

CONCLUSIONS

Hmgcs2 had the most critical regulatory role in DCM. We for the first time reported that miR-363-5p inhibited Hmgcs2 expression, thereby alleviating HG-induced cardiomyocyte injury.

Characterization of Non-Ischemic Dilated Cardiomyopathy in a Native Tanzanian Cohort: MOYO Study

Background

Non-ischemic dilated cardiomyopathy (NIDCM) is a common cause of heart failure with progressive tendency. The disease occurs in one in every 2,500 individuals in the developed world, with high morbidity and mortality. However, detailed data on the role of NIDCM in heart failure in Tanzania is lacking.

Aim

To characterize NIDCM in a Tanzanian cohort with respect to demographics, clinical profile, imaging findings and management.

Methods

Characterization of non-ischemic dilated cardioMyOpathY in a native Tanzanian cOhort (MOYO) is a prospective cohort study of NIDCM patients seen at the Jakaya Kikwete Cardiac Institute. Patients aged ≥18 years with a clinical diagnosis of heart failure, an ejection fraction of ≤45% on echocardiography and no evidence of ischemia were enrolled. Clinical data, echocardiography, electrocardiography (ECG), coronary angiography and stress ECG information were collected from February 2020 to March 2022.

Results

Of 402 patients, n = 220 (54.7%) were males with a median (IQR) age of 55.0 (41.0, 66.0) years. Causes of NIDCM were presumably hypertensive n = 218 (54.2%), idiopathic n = 116 (28.9%), PPCM n = 45 (11.2%), alcoholic n = 10 (2.5%) and other causes n = 13 (3.2%). The most common presenting symptoms were dyspnea n = 342 (85.1%), with the majority of patients presenting with New York Heart Association (NYHA) Class III n = 195 (48.5%). The mean (SD) left ventricular ejection fraction (LVEF) was 29.4% (±7.7), and severe systolic dysfunction (LVEF <30%) was common n = 208 (51.7%). Compared with other forms of DCM, idiopathic DCM patients were significantly younger, had more advanced NYHA class (p < 0.001) and presented more often with left bundle branch block on ECG (p = 0.0042). There was suboptimal use of novel guidelines recommended medications ARNI n = 10 (2.5%) and SGLT2 2-inhibitors n = 2 (0.5%).

Conclusions

In our Tanzanian cohort, the majority of patients with NIDCM have an identified underlying cause, and they present at late stages of the disease. Patients with idiopathic DCM are younger with more severe disease compared to other forms of NIDCM.

Chitosan Versus Dapagliflozin in a Diabetic Cardiomyopathy Mouse Model

Diabetes mellitus is a metabolic disorder with global economic implications that can lead to complications such as diabetic cardiomyopathy. The aim of this study was to compare the effects of chitosan versus dapagliflozin in mouse diabetic cardiomyopathy. We used 32 C57Bl/6 male mice aged between 8 and 10 weeks, which were randomly divided into Control-without diabetes mellitus (DM), type 1 DM (T1DM), T1DM + Chitosan, and T1DM + Dapapgliflozin groups. We induced diabetes with streptozotocin and treated the animals for 12 weeks. The analysis showed a reduction in intramyocardial fibrosis in the T1DM + Dapapgliflozin compared to T1DM animals. In T1DM + CHIT, a reduction in intramyocardial fibrosis was observed although, accordingly, there was also no significant decrease in blood glucose. The level of oxidative stress was reduced in the groups of treated animals compared to T1DM. All these observed changes in the structure and function of hearts were highlighted in the echocardiographic examination. In the treated groups, there was delayed appearance of left ventricular (LV) hypertrophy, a slight decrease in the ejection fraction of the LV, and an improved diastolic profile. The results demonstrate that chitosan has promising effects on diabetic cardiomyopathy that are comparable to the beneficial effects of dapagliflozin.

Rev-erbα attenuates diabetic myocardial injury through regulation of ferroptosis

Diabetes is a widespread disease that threatens the life and health of human beings, and diabetic cardiomyopathy (DCM) is one of the major complications of diabetic patients. The pathological mechanisms of DCM are complex, including inflammation, endoplasmic reticulum stress, and oxidative stress that have been reported previously. Although recent studies suggested that ferroptosis is also involved in the progression of DCM, the exact mechanism remains unclear. Rev-erbα cardiac conditional knockout mice were generated and type 2 diabetes were induced by high fat diet (HFD) and intraperitoneal injection of streptozotocin (STZ) in in vivo experiments. In parallel, our in vitro experiments entailed the introduction of elevated levels of glucose (HG) and palmitic acid (PA) to induce glycolipid toxicity in H9c2 cardiomyocytes. Further deterioration of cardiac function was detected by echocardiography after the clock gene rev-erbα was knocked out. This was accompanied by significant elevations in markers of inflammation, myocardial fibrosis, and oxidative stress. In addition, iron content, transmission electron microscopy (TEM), and RT-PCR assays confirmed significantly increased levels of ferroptosis in rev-erbα-deficient DCM. Intriguingly, Co-Immunoprecipitation (Co-IP) data uncovered an interaction between rev-erbα and nuclear factor E2-related factor 2 (NRF2) in diabetic myocardial tissues. It is worth highlighting that ferroptosis within cardiomyocytes witnessed significant mitigation upon the administration of sulforaphane (SFN), an NRF2 agonist, to HG + PA-incubated H9c2 cells. Our study demonstrates for the first time that knockdown of the clock gene rev-erbα exacerbates myocardial injury and ferroptosis in type 2 diabetic mice, which can be reversed by activating NRF2.

Effect of exercise on improving myocardial mitochondrial function in decreasing diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) is a significant cause of heart failure in patients with diabetes, and its pathogenesis is closely related to myocardial mitochondrial injury and functional disability. Studies have shown that the development of diabetic cardiomyopathy is related to disorders in mitochondrial metabolic substrates, changes in mitochondrial dynamics, an imbalance in mitochondrial Ca2+ regulation, defects in the regulation of microRNAs, and mitochondrial oxidative stress. Physical activity may play a role in resistance to the development of diabetic cardiomyopathy by improving myocardial mitochondrial biogenesis, the level of autophagy and dynamic changes in fusion and division; enhancing the ability to cope with oxidative stress; and optimising the metabolic substrates of the myocardium. This paper puts forward a new idea for further understanding the specific mitochondrial mechanism of the occurrence and development of diabetic cardiomyopathy and clarifying the role of exercise-mediated myocardial mitochondrial changes in the prevention and treatment of diabetic cardiomyopathy. This is expected to provide a new theoretical basis for exercise to reduce diabetic cardiomyopathy symptoms.

Beyond the beat: A pioneering investigation into exercise modalities for alleviating diabetic cardiomyopathy and enhancing cardiac health

Patients with preexisting cardiovascular disease or those at high risk for developing the condition are often offered exercise as a form of therapy. Patients with cancer who are at an increased risk for cardiovascular issues are increasingly encouraged to participate in exercise-based, interdisciplinary programs due to the positive correlation between these interventions and clinical outcomes following myocardial infarction. Diabetic cardiomyopathy (DC) is a cardiac disorder that arises due to disruptions in the homeostasis of individuals with diabetes. One of the primary reasons for mortality in individuals with diabetes is the presence of cardiac structural damage and functional abnormalities, which are the primary pathological features of DC. The aetiology of dilated cardiomyopathy is multifaceted and encompasses a range of processes, including metabolic abnormalities, impaired mitochondrial function, dysregulation of calcium ion homeostasis, excessive cardiomyocyte death, and fibrosis. In recent years, many empirical investigations have demonstrated that exercise training substantially impacts the prevention and management of diabetes. Exercise has been found to positively impact the recovery of diabetes and improve several metabolic problem characteristics associated with DC. One potential benefit of exercise is its ability to increase systolic activity, which can enhance cardiometabolic and facilitate the repair of structural damage to the heart caused by DC, leading to a direct improvement in cardiac health. In contrast, exercise has the potential to indirectly mitigate the pathological progression of DC through its ability to decrease circulating levels of sugar and fat while concurrently enhancing insulin sensitivity. A more comprehensive understanding of the molecular mechanism via exercise facilitates the restoration of DC disease must be understood. Our goal in this review was to provide helpful information and clues for developing new therapeutic techniques for motion alleviation DC by examining the molecular mechanisms involved.

An Overview of Diabetic Cardiomyopathy

Diabetic cardiomyopathy (DCM) is a myocardial disorder that is characterised by structural and functional abnormalities of the heart muscle in the absence of hypertension, valvular heart disease, congenital heart defects, or coronary artery disease (CAD). After witnessing a particular form of cardiomyopathy in diabetic individuals, Rubler et al. came up with the moniker diabetic cardiomyopathy in 1972. Four stages of DCM are documented, and the American College of Cardiology/American Heart Association Stage and New York Heart Association Class for HF have some overlap. Diabetes is linked to several distinct forms of heart failure. Around 40% of people with heart failure with preserved ejection fraction (HFpEF) have diabetes, which is thought to be closely associated with the pathophysiology of HFpEF. Diabetes and HF are uniquely associated in a bidirectional manner. When compared to the general population without diabetes, those with diabetes have a risk of heart failure that is up to four times higher. A biomarker is a trait that is reliably measured and assessed as a predictor of healthy biological activities, pathological processes, or pharmacologic responses to a clinical treatment. Several biomarker values have been discovered to be greater in patients with diabetes than in control subjects among those who have recently developed heart failure. Myocardial fibrosis and hypertrophy are the primary characteristics of DCM, and structural alterations in the diabetic myocardium are often examined by non-invasive, reliable, and reproducible procedures. An invasive method called endomyocardial biopsy (EMB) is most often used to diagnose many cardiac illnesses.

Glucose increases proliferation and chemoresistance in chronic myeloid leukemia via decreasing antioxidant Properties of ω-3 polyunsaturated fatty acids in the presence of Iron

BACKGROUND

There is a strong association between hyperglycemia, oxidative stress, inflammation and the onset and progression of diabetes which causes a higher risk of cancer. This study investigated, the effect of concomitant use of omega-3 polyunsaturated fatty acids (ω-3 PUFAs) with iron supplements in hyper-glucose conditions on the K-562 cell line.

METHODS

The effects of iron, ω-3 PUFAs, and a combination of both on K-562 cells were investigated under normal and high glucose conditions. The impact of these treatments was evaluated using multiple methodologies, including the MTT assay for cell viability, quantification of oxidative stress markers [total antioxidant capacity (TAC) and malondialdehyde (MDA)], and analysis of the cell cycle. Furthermore, the expression levels of TNFα and p53 mRNA were measured using Real-time PCR.

RESULTS

The co-treatment of ω-3 PUFAs and iron in the presence of high glucose had notable effects, as evidenced by an increase in cell survival, resistance to imatinib chemotherapy, TNFαmRNA expression levels, MDA levels, and percentage of cells in the G2/S phase. Additionally, there was a decrease in the mRNA expression of p53 and TAC levels compared to treatment in the normal-glucose condition.

CONCLUSION

Hyperglycemic conditions in conjunction with the combined treatment of theω-3 PUFAs and iron, led to reduced anticancer capacity, chemosensitivity, anti-inflammatory and antioxidant properties of the K-562 cells. These effects were found to be mediated by oxidative stress.

Impact of inflammation and anti-inflammatory modalities on diabetic cardiomyopathy healing: From fundamental research to therapy

Diabetic cardiomyopathy (DCM) is a prevalent cardiovascular complication of diabetes mellitus, characterized by high morbidity and mortality rates worldwide. However, treatment options for DCM remain limited. For decades, a substantial body of evidence has suggested that the inflammatory response plays a pivotal role in the development and progression of DCM. Notably, DCM is closely associated with alterations in inflammatory cells, exerting direct effects on major resident cells such as cardiomyocytes, vascular endothelial cells, and fibroblasts. These cellular changes subsequently contribute to the development of DCM. This article comprehensively analyzes cellular, animal, and human studies to summarize the latest insights into the impact of inflammation on DCM. Furthermore, the potential therapeutic effects of current anti-inflammatory drugs in the management of DCM are also taken into consideration. The ultimate goal of this work is to consolidate the existing literature on the inflammatory processes underlying DCM, providing clinicians with the necessary knowledge and tools to adopt a more efficient and evidence-based approach to managing this condition.

Inhibition of miR-543 alleviates cardiac fibroblast-to-myofibroblast transformation and collagen expression in insulin resistance via targeting PTEN

BACKGROUND

Myocardial interstitial fibrosis is an important manifestation of diabetic heart disease, and insulin resistance is one of the mechanisms of myocardial interstitial fibrosis. Some studies have found that miR-543 is associated with insulin resistance, but whether it plays a role in diabetic myocardial interstitial fibrosis remains unclear. This study aimed to investigate the role of miR-543 in diabetic myocardial interstitial fibrosis.

METHODS

The combination of high glucose and high insulin was used to establish an insulin-resistant myocardial fibroblast model. The expression levels of miR-543, α-SMA, collagen Ⅰ, collagen Ⅲ and PTEN were detected. Cell proliferation and migration were detected. Luciferase reporter gene assay was used to verify the targeting relationship between miR-543 and PTEN.

RESULTS

The expression of miR-543 was up-regulated in myocardial fibroblasts with insulin resistance, which was consistent with the results of bioinformatics analysis. The proliferation and migration levels of myocardial fibroblasts in insulin-resistant states were increased, and the expression levels of α-SMA, collagen Ⅰ and collagen Ⅲ were also increased. Inhibition of miR-543 expression could reverse the above changes. Target gene prediction and dual luciferase reporter assay demonstrated that miR-543 could bind to the 3'UTR region of PTEN. Moreover, the effect of miR-543 on insulin-resistant myocardial fibroblasts is mediated by targeting PTEN.

CONCLUSIONS

Inhibition of miR-543 can reduce myocardial fibroblast-myofibroblast transformation and collagen expression in insulin-resistant states by targeting PTEN.

β-elemene alleviates hyperglycemia-induced cardiac inflammation and remodeling by inhibiting the JAK/STAT3-NF-κB pathway

BACKGROUND

Hyperglycemic induced cardiac hypertrophy and cardiac inflammation are important pathological processes in diabetic cardiomyopathy. β-elemene (Ele) is a natural compound extracted from Curcuma Rhizoma and has anti-tumor effects. It also has therapeutic effects in some inflammatory diseases. However, the therapeutic effect of Ele on diabetic cardiomyopathy is not clear. The purpose of this study was to evaluate the effect of Ele on hyperglycemia-caused cardiac remodeling and heart failure.

METHODS

C57BL/6 mice were intraperitoneally injected with streptozotocin to induce DCM, and Ele was administered intragastric after 8 weeks to investigate the effect of Ele. RNA sequencing of cardiac tissue was performed to investigate the mechanism.

RESULTS

Ele markedly inhibited cardiac inflammation, fibrosis and hypertrophy in diabetic mice, as well as in high glucose-induced cardiomyocytes. RNA sequencing showed that cardioprotective effect of Ele involved the JAK/STAT3-NF-κB signaling pathway. Ele alleviated heart and cardiomyocyte inflammation in mice by blocking diabetes-induced JAK2 and STAT3 phosphorylation and NF-κB activation.

CONCLUSIONS

The study found that Ele preserved the hearts of diabetic mice by inhibiting JAK/STAT3 and NF-κB mediated inflammatory responses, suggesting that Ele is an effective therapy for DCM.

Efficacy of traditional Chinese medicine on diabetic cardiomyopathy in animal models: a systematic review and meta-analysis

Background: Diabetic cardiomyopathy (DCM) is a severe complication of diabetes that can diminish the quality of life in patients and is a leading cause of death. Research has demonstrated the effectiveness of Traditional Chinese Medicine (TCM) in reducing blood sugar levels and protecting cardiovascular function in both animal models and clinical research studies. Nevertheless, the efficacy of TCM in animal models of DCM has not been analyzed systematically. Method: We searched the following electronic bibliographic databases: Web of Science, PubMed, Cochrane Library, and CNKI(China National Knowledge Infrastructure). Studies that reported the efficacy of TCM in animals with DCM were included. The literature search was conducted using the terms. The data will be restricted from the year 2013 to 24 April 2023, 24 studies were included in the meta-analysis. Result: A total of 24 Traditional Chinese Medicine interventions and 2157 animals met the inclusion criteria. The pooled data revealed that TCM interventions resulted in significant improvements in body weight (BW), heart weight (HW) to body weight ratio (HW/BW), triglyceride (TG) and cholesterol (TC) levels, ejection fraction (EF), fractional shortening (FS) and E/A ratio. Subgroup analysis and meta-regression revealed that the type of TCM, duration of intervention, method of modeling, and animal species were potential sources of heterogeneity. Conclusion: TCM interventions were associated with significant improvements in body weight, heart weight to body weight ratio, triglyceride and cholesterol levels, left ventricular internal dimension in systole, ejection fraction, fractional shortening and E/A ratio. The heterogeneity in the results was found to be potentially due to the type of TCM, duration of intervention, method of modeling, and animal species, as shown in subgroup analysis and meta-regression. Systematic Review Registration: identifier CRD42023402908.

MALAT1/miR-185-5p mediated high glucose-induced oxidative stress, mitochondrial injury and cardiomyocyte apoptosis via the RhoA/ROCK pathway

To explore the underlying mechanism of lncRNA MALAT1 in the pathogenesis of diabetic cardiomyopathy (DCM). DCM models were confirmed in db/db mice. MiRNAs in myocardium were detected by miRNA sequencing. The interactions of miR-185-5p with MALAT1 and RhoA were validated by dual-luciferase reporter assays. Primary neonatal cardiomyocytes were cultured with 5.5 or 30 mmol/L D-glucose (HG) in the presence or absence of MALAT1-shRNA and fasudil, a ROCK inhibitor. MALAT1 and miR-185-5p expression were determined by real-time quantitative PCR. The apoptotic cardiomyocytes were evaluated using flow cytometry and TUNEL staining. SOD activity and MDA contents were measured. The ROCK activity, phosphorylation of Drp1S616 , mitofusin 2 and apoptosis-related proteins were analysed by Western blotting. Mitochondrial membrane potential was examined by JC-1. MALAT1 was significantly up-regulated while miR-185-5p was down-regulated in myocardium of db/db mice and HG-induced cardiomyocytes. MALAT1 regulated RhoA/ROCK pathway via sponging miR-185-5p in cardiomyocytes in HG. Knockdown of MALAT1 and fasudil all inhibited HG-induced oxidative stress, and alleviated imbalance of mitochondrial dynamics and mitochondrial dysfunction, accompanied by reduced cardiomyocyte apoptosis. MALAT1 activated the RhoA/ROCK pathway via sponging miR-185-5p and mediated HG-induced oxidative stress, mitochondrial damage and apoptosis of cardiomyocytes in mice.

Ultrasound-targeted semaglutide-loaded PEG-nanoliposomes microbubble destruction protects diabetic cardiomyopathy by activating PI3K/Akt/Nrf2 signaling pathway

Objective

To investigate the ameliorative effect of Semaglutide-loaded PEG-nanoliposomes (Sem-PEG-lips) combined with ultrasound-targeted microbubble destruction (UTMD) on streptozotocin (STZ)-induced diabetic cardiomyopathy (DCM) in rodents and its potential mechanisms.

Methods

Sem-PEG-lips were prepared by the reverse phase evaporation method. Fifty STZ-induced diabetic rats were randomly divided into DCM model group, Sem or Sem-PEG-lips alone treatment group, UTMD + Sem group and UTMD + Sem-PEG-lips group (n = 10), respectively, and used the healthy rats as normal control. During the 12-week intervention, the weight and blood glucose levels of all rats were recorded. Myocardial injury and fibrosis were observed by using H&E and Masson staining. The activity of antioxidant enzymes and the expression levels of oxidative stress-related signaling pathway markers in myocardial tissues were measured by ELISA and western blotting method, respectively.

Results

Compared with DCM rats, the body weight and blood glucose levels of those in the UTMD + Sem-PEG-lips group were significantly increased and decreased, respectively (both p < 0.05). The results of H&E and Masson staining showed that myocardial fibrosis and apoptosis were both significantly improved in combination group (both p < 0.001). Further results of ELISA and Western blot analysis showed that the activity of antioxidant enzymes in ones received combination therapy were significantly higher than that in DCM model group (all p < 0.001), and the expression of PI3K/Akt/Nrf2 signaling pathway related proteins were significantly up-regulated (all p < 0.001), and all these changes were reversed by the treatment of PI3K inhibitor. results.

Conclusion

UTMD combined Sem-PEG-lips can reduce the oxidative stress of myocardial tissue in DCM rats by activating PI3K/Akt/Nrf2 signaling pathway, thereby improving diabetic myocardial injury.

Nuclear import of Mas-related G protein-coupled receptor member D induces pathological cardiac remodeling

Alamandine (Ala), a ligand of Mas-related G protein-coupled receptor, member D (MrgD), alleviates angiotensin II (AngII)-induced cardiac hypertrophy. However, the specific physiological and pathological role of MrgD is not yet elucidated. Here, we found that MrgD expression increased under various pathological conditions. Then, MrgD knockdown prevented AngII-induced cardiac hypertrophy and fibrosis via inactivating Gα_i-mediacted downstream signaling pathways, including the phosphorylation of p38 (p-P38), while MrgD overexpression induced pathological cardiac remodeling. Next, Ala, like silencing MrgD, exerted its cardioprotective effects by inhibiting Ang II-induced nuclear import of MrgD. MrgD interacted with p-P38 and promoted its entry into the nucleus under Ang II stimulation. Our results indicated that Ala was a blocking ligand of MrgD that inhibited downstream signaling pathway, which unveiled the promising cardioprotective effect of silencing MrgD expression on alleviating cardiac remodeling. Video Abstract.

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.

Whey Improves In Vitro Endothelial Mitochondrial Function and Metabolic Redox Status in Diabetic State

Endothelial dysfunction plays a critical role in the progression of type 2 diabetes mellitus (T2DM), leading to cardiovascular complications. Current preventive antioxidant strategies to reduce oxidative stress and improve mitochondrial function in T2DM highlight dietary interventions as a promising approach, stimulating the deepening of knowledge of food sources rich in bioactive components. Whey (WH), a dairy by-product with a considerable content of bioactive compounds (betaines and acylcarnitines), modulates cancer cell metabolism by acting on mitochondrial energy metabolism. Here, we aimed at covering the lack of knowledge on the possible effect of WH on the mitochondrial function in T2DM. The results showed that WH improved human endothelial cell (TeloHAEC) function during the in vitro diabetic condition mimicked by treating cells with palmitic acid (PA) (0.1 mM) and high glucose (HG) (30 mM). Of note, WH protected endothelial cells from PA+HG-induced cytotoxicity (p < 0.01) and prevented cell cycle arrest, apoptotic cell death, redox imbalance, and metabolic alteration (p < 0.01). Moreover, WH counteracted mitochondrial injury and restored SIRT3 levels (p < 0.01). The SiRNA-mediated suppression of SIRT3 abolished the protective effects exerted by WH on the mitochondrial and metabolic impairment caused by PA+HG. These in vitro results reveal the efficacy of whey as a redox and metabolic modulator in the diabetic state and pave the way for future studies to consider whey as the source of dietary bioactive molecules with health benefits in preventive strategies against chronic diseases.

Diabetic cardiomyopathy: an educational review

This educational review provides information about the epidemiology of diabetes and heart failure (diabetic cardiomyopathy) and the challenges in diagnosis and screening. Details on how to investigate patients with imaging and other modalities are discussed, as well as an update regarding the efficacy and safety of novel agents for treatment of diabetic cardiomyopathy.

Efficiency comparison of an isoeugenol-derivated compound, eugenosedin-A, with glibenclamide and pioglitazone in protecting cardiovascular dysfunction of diabetic SHR

This study was to investigate three agents possible protective effect against DM-induced cardiovascular dysfunction in spontaneously hypertensive rats (SHR). Control group was fed normal diet, DM group was injected with STZ/NA and fed high fat diet (HFD), and treatment groups were given STZ/NA, fed HFD, and then oral gavaged with eugenosedin-A (Eu-A), glibenclamide (Gli), or pioglitazone (Pio) 5 mg/kg/per day for 4-week, respectively. Eu-A, Gli, and Pio clearly ameliorated the changes of body weight, cardiac weight, and the biochemical parameters, cardiovascular disorders and inflammation. Like Gli and Pio, Eu-A may be effectively to control DM and the cardiovascular dysfunction.

LncRNA DANCR deficiency promotes high glucose-induced endothelial to mesenchymal transition in cardiac microvascular cells via the FoxO1/DDAH1/ADMA signaling pathway

Cardiac fibrosis is the main pathological basis of diabetic cardiomyopathy (DCM), and endothelial-to-meschenymal transition (EndMT) is a key driver to cardiac fibrosis and plays an important role in the pathogenesis of DCM. Asymmetric dimethylarginine (ADMA), a crucial pathologic factor in diabetes mellitus, is involved in organ fibrosis. This study aims to evaluate underlying mechanisms of ADMA in DCM especially for EndMT under diabetic conditions. A diabetic rat model was induced by streptozotocin (STZ) injection, and human cardiac microvascular endothelial cells (HCMECs) were stimulated with high glucose to induce EndMT. Subsequently, the role of ADMA in EndMT was detected either by exogenous ADMA or by over-expressing dimethylarginine dimethylaminohydrolase 1 (DDAH1, degradation enzyme for ADMA) before high glucose stimulation. Furthermore, the relationships among forkhead box protein O1 (FoxO1), DDAH1 and ADMA were evaluated by FoxO1 over-expression or FoxO1 siRNA. Finally, we examined the roles of LncRNA DANCR in FoxO1/DDAH1/ADMA pathway and EndMT of HCMECs. Here, we found that EndMT in HCMECs was induced by high glucose, as evidenced by down-regulated expression of CD31 and up-regulated expression of FSP-1 and collagen Ⅰ. Importantly, ADMA induced EndMT in HCMECs, and over-expressing DDAH1 protected from developing EndMT by high glucose. Furthermore, we demonstrated that over-expression of FoxO1-ADA with mutant phosphorylation sites of T24A, S256D, and S316A induced EndMT of HCMECs by down-regulating of DDAH1 and elevating ADMA, and that EndMT of HCMECs induced by high glucose was reversed by FoxO1 siRNA. We also found that LncRNA DANCR siRNA induced EndMT of HCMECs, activated FoxO1, and inhibited DDAH1 expression. Moreover, over-expression of LncRNA DANCR could markedly attenuated high glucose-mediated EndMT of HCMECs by inhibiting the activation of FoxO1 and increasing the expression of DDAH1. Collectively, our results indicate that LncRNA DANCR deficiency promotes high glucose-induced EndMT in HCMECs by regulating FoxO1/DDAH1/ADMA pathway.

Costunolide alleviates hyperglycaemia-induced diabetic cardiomyopathy via inhibiting inflammatory responses and oxidative stress

Hyperglycaemia-induced myocardial injury promotes the induction of heart failure in diabetic patients. Impaired antioxidant capability and sustained chronic inflammation play a vital role in the progression of diabetic cardiomyopathy (DCM). Costunolide (Cos), a natural compound with anti-inflammatory and antioxidant properties, has exhibited therapeutic effects in various inflammatory diseases. However, the role of Cos in diabetes-induced myocardial injury remains poorly understood. In this study, we investigated the effect of Cos on DCM and explored the potential mechanisms. C57BL/6 mice were administered intraperitoneal streptozotocin for DCM induction. Cos-mediated anti-inflammatory and antioxidation activities were examined in heart tissues of diabetic mice and high glucose (HG)-stimulated cardiomyocytes. Cos markedly inhibited HG-induced fibrotic responses in diabetic mice and H9c2 cells, respectively. The cardioprotective effects of Cos could be correlated to the reduced expression of inflammatory cytokines and decreased oxidative stress. Further investigations demonstrated Cos reversed diabetes-induced nuclear factor-κB (NF-κB) activation and alleviated impaired antioxidant defence system, principally via activation of nuclear factor-erythroid 2 p45-related factor-2 (Nrf-2). Cos alleviated cardiac damage and improved cardiac function in diabetic mice by inhibiting NF-κB-mediated inflammatory responses and activating the Nrf-2-mediated antioxidant effects. Therefore, Cos could be a potential candidate for the treatment of DCM.

Roxadustat, a HIF-PHD inhibitor with exploitable potential on diabetes-related complications

Diabetes mellitus (DM) is a group of metabolic diseases caused by absolute or relative deficiency of insulin secretion and characterized by chronic hyperglycemia. Its complications affect almost every tissue of the body, usually leading to blindness, renal failure, amputation, etc. and in the final stage, it mostly develops into cardiac failure, which is the main reason why diabetes mellitus manifests itself as a high clinical lethality. The pathogenesis of diabetes mellitus and its complications involves various pathological processes including excessive production of mitochondrial reactive oxygen species (ROS) and metabolic imbalance. Hypoxia-inducible Factor (HIF) signaling pathway plays an important role in both of the above processes. Roxadustat is an activator of Hypoxia-inducible Factor-1α, which increases the transcriptional activity of Hypoxia-inducible Factor-1α by inhibiting hypoxia-inducible factor prolyl hydroxylase (HIF-PHD). Roxadustat showed regulatory effects on maintaining metabolic stability in the hypoxic state of the body by activating many downstream signaling pathways such as vascular endothelial growth factor (VEGF), glucose transporter protein-1 (GLUT1), lactate dehydrogenase (LDHA), etc. This review summarizes the current research findings of roxadustat on the diseases of cardiomyopathy, nephropathy, retinal damage and impaired wound healing, which also occur at different stages of diabetes and greatly contribute to the damage caused by diabetes to the organism. We attempts to uncover a more comprehensive picture of the therapeutic effects of roxadustat, and inform its expanding research about diabetic complications treatment.

Silencing RIPK1/mTORC1 signalling attenuated the inflammation and oxidative stress in diabetic cardiomyopathy

BACKGROUND

Diabetes cardiomyopathy (DCM) is one of the major risk factors for the heart failure of the diabetic patients. RIPK1 maybe participate in the regulation of the oxidative stress and inflammation during DCM.

METHODS

H&E and Masson staining were utilized to assess the inflammation and fibrosis in myocardial tissues. CCK-8 and TUNEL staining were utilized to analyze cell viability and apoptosis, respectively. SOD activity and MDA content were detected utilizing the kits. The formation of autophagosomes was measured by immunofluorescence assay.

RESULTS

RIPK1 and RPTOR (a component of mTORC1) expression and oxidative stress level were upregulated, but autophagy was decreased in the myocardial tissues of DCM rat characterized by the high body weight and blood glucose, abnormal cardiac function, myocardial inflammation and fibrosis. High glucose (HG) treatment resulted in cell viability and autophagy level decreasing, inflammatory cytokines expression increasing and oxidative stress increasing in cardiac fibroblasts (CFs). Meanwhile, RIPK1 and RPTOR expression also was increased in HG-treated cells. HG-induced CFs apoptosis, inflammation, oxidative stress and the inhibition of HG to cell viability and autophagy was partly reversed by the inhibitor of RIPK1 and mTORC1.

CONCLUSION

Overall, RIPK1/mTORC1 signalling suppression improved HG-induced apoptosis, inflammation and oxidative stress through activation autophagy. These data provided a reliable evidence that RIPK1 may be a potential target for DCM therapeutic.

Diabetic cardiomyopathy: The role of microRNAs and long non-coding RNAs

Diabetes mellitus (DM) is on the rise, necessitating the development of novel therapeutic and preventive strategies to mitigate the disease's debilitating effects. Diabetic cardiomyopathy (DCMP) is among the leading causes of morbidity and mortality in diabetic patients globally. DCMP manifests as cardiomyocyte hypertrophy, apoptosis, and myocardial interstitial fibrosis before progressing to heart failure. Evidence suggests that non-coding RNAs, such as long non-coding RNAs (lncRNAs) and microRNAs (miRNAs), regulate diabetic cardiomyopathy-related processes such as insulin resistance, cardiomyocyte apoptosis and inflammation, emphasizing their heart-protective effects. This paper reviewed the literature data from animal and human studies on the non-trivial roles of miRNAs and lncRNAs in the context of DCMP in diabetes and demonstrated their future potential in DCMP treatment in diabetic patients.

The Role of microRNA in the Development, Diagnosis, and Treatment of Cardiovascular Disease: Recent Developments

Since their discovery in 1993, microRNAs (miRNAs) have emerged as important regulators of many crucial cellular processes, and their dysregulation have been shown to contribute to multiple pathologic conditions, including cardiovascular disease (CVD). miRNAs have been found to regulate the expression of various genes involved in cardiac development and function and in the development and progression of CVD. Many miRNAs are master regulators fine-tuning the expression of multiple, often interrelated, genes involved in inflammation, apoptosis, fibrosis, senescence, and other processes crucial for the development of different forms of CVD. This article presents a review of recent developments in our understanding of the role of miRNAs in the development of CVD and surveys their potential applicability as therapeutic targets and biomarkers to facilitate CVD diagnosis, prognosis, and treatment. There are currently multiple potential miRNA-based therapeutic agents in different stages of development, which can be grouped into two classes: miRNA mimics (replicating the sequence and activity of their corresponding miRNAs) and antagomiRs (antisense inhibitors of specific miRNAs). However, in spite of promising preliminary data and our ever-increasing knowledge about the mechanisms of action of specific miRNAs, miRNA-based therapeutics and biomarkers have yet to be approved for clinical applications. SIGNIFICANCE STATEMENT: Over the last few years microRNAs have emerged as crucial, specific regulators of the cardiovascular system and in the development of cardiovascular disease, by posttranscriptional regulation of their target genes. The minireview presents the most recent developments in this area of research, including the progress in diagnostic and therapeutic applications of microRNAs. microRNAs seem very promising candidates for biomarkers and therapeutic agents, although some challenges, such as efficient delivery and unwanted effects, need to be resolved.

A comprehensive review of the novel therapeutic targets for the treatment of diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) is characterized by structural and functional abnormalities in the myocardium affecting people with diabetes. Treatment of DCM focuses on glucose control, blood pressure management, lipid-lowering, and lifestyle changes. Due to limited therapeutic options, DCM remains a significant cause of morbidity and mortality in patients with diabetes, thus emphasizing the need to develop new therapeutic strategies. Ongoing research is aimed at understanding the underlying molecular mechanism(s) involved in the development and progression of DCM, including oxidative stress, inflammation, and metabolic dysregulation. The goal is to develope innovative pharmaceutical therapeutics, offering significant improvements in the clinical management of DCM. Some of these approaches include the effective targeting of impaired insulin signaling, cardiac stiffness, glucotoxicity, lipotoxicity, inflammation, oxidative stress, cardiac hypertrophy, and fibrosis. This review focuses on the latest developments in understanding the underlying causes of DCM and the therapeutic landscape of DCM treatment.

The novel inflammatory biomarker GlycA and triglyceride-rich lipoproteins are associated with the presence of subclinical myocardial dysfunction in subjects with type 1 diabetes mellitus

BACKGROUND

Subjects with Type 1 diabetes mellitus (T1DM) have an increased incidence of heart failure (HF). Several pathophysiological mechanisms have been involved in its development. The aim of this study was to analyze the potential contribution of the advanced lipoprotein profile and plasma glycosylation (GlycA) to the presence of subclinical myocardial dysfunction in subjects with T1DM.

METHODS

We included subjects from a Danish cohort of T1DM subjects (Thousand & 1 study) with either diastolic and/or systolic subclinical myocardial dysfunction, and a control group without myocardial dysfunction, matched by age, sex and HbA1c. All underwent a transthoracic echocardiogram and an advanced lipoprotein profile obtained by using the NMR-based Liposcale® test. GlycA NMR signal was also analyzed. Systolic dysfunction was defined as left ventricular ejection fraction ≤ 45% and diastolic dysfunction was considered as E/e'≥12 or E/e' 8-12 + volume of the left atrium > 34 ml/m2. To identify a metabolic profile associated with the presence of subclinical myocardial dysfunction, a multivariate supervised model of classification based on least squares regression (PLS-DA regression) was performed.

RESULTS

One-hundred forty-six subjects had diastolic dysfunction and 18 systolic dysfunction. Compared to the control group, patients with myocardial dysfunction had longer duration of diabetes (p = 0.005), and higher BMI (p = 0.013), serum NTproBNP concentration (p = 0.001), systolic blood pressure (p < 0.001), albuminuria (p < 0.001), and incidence of advanced retinopathy (p < 0.001). The supervised classification model identified a specific pattern associated with myocardial dysfunction, with a capacity to discriminate patients with myocardial dysfunction from controls. PLS-DA showed that triglyceride-rich lipoproteins (TGRLs), such as VLDL (total VLDL particles, large VLDL subclass and VLDL-TG content) and IDL (IDL cholesterol content), as well as the plasma concentration of GlycA, were associated with the presence of subclinical myocardial dysfunction.

CONCLUSION

Proatherogenic TGRLs and the proinflammatory biomarker Glyc A are strongly associated to myocardial dysfunction in T1DM. These findings suggest a pivotal role of TGRLs and systemic inflammation in the development of subclinical myocardial dysfunction in T1DM.

Citronellal Attenuates Oxidative Stress-Induced Mitochondrial Damage through TRPM2/NHE1 Pathway and Effectively Inhibits Endothelial Dysfunction in Type 2 Diabetes Mellitus

In type 2 diabetes mellitus (T2DM), oxidative stress induces endothelial dysfunction (ED), which is closely related to the formation of atherosclerosis. However, there are few effective drugs to prevent and cure it. Citronellal (CT) is an aromatic active substance extracted from citronella plants. Recently, CT has been shown to prevent ED, but the underlying mechanism remains unclear. The purpose of this study was to investigate whether CT ameliorated T2DM-induced ED by inhibiting the TRPM2/NHE1 signal pathway. Transient receptor potential channel M2 (TRPM2) is a Ca²⁺-permeable cation channel activated by oxidative stress, which damages endothelial cell barrier function and further leads to ED or atherosclerosis in T2DM. The Na⁺/H⁺ exchanger 1 (NHE1), a transmembrane protein, also plays an important role in ED. Whether TRPM2 and NHE1 are involved in the mechanism of CT improving ED in T2DM still needs further study. Through the evaluations of ophthalmoscope, HE and Oil red staining, vascular function, oxidative stress level, and mitochondrial membrane potential evaluation, we observed that CT not only reduced the formation of lipid deposition but also inhibited ED and suppressed oxidative stress-induced mitochondrial damage in vasculature of T2DM rats. The expressions of NHE1 and TRPM2 was up-regulated in the carotid vessels of T2DM rats; NHE1 expression was also upregulated in endothelial cells with overexpression of TRPM2, but CT reversed the up-regulation of NHE1 in vivo and in vitro. In contrast, CT had no inhibitory effect on the expression of NHE1 in TRPM2 knockout mice. Our study show that CT suppressed the expression of NHE1 and TPRM2, alleviated oxidative stress-induced mitochondrial damage, and imposed a protective effect on ED in T2DM rats.

ADAM17 knockdown mitigates while ADAM17 overexpression aggravates cardiac fibrosis and dysfunction via regulating ACE2 shedding and myofibroblast transformation

A disintegrin and metalloprotease domain family protein 17 (ADAM17) is a new member of renin-angiotensin system (RAS) but its role in the pathogenesis of diabetic cardiomyopathy (DCM) is obscure. To test the hypothesis that ADAM17 knockdown mitigates while ADAM17 overexpression aggravates cardiac fibrosis via regulating ACE2 shedding and myofibroblast transformation in diabetic mice, ADAM17 gene was knocked down and overexpressed by means of adenovirus-mediated short-hairpin RNA (shRNA) and adenovirus vector carrying ADAM17 cDNA, respectively, in a mouse model of DCM. Two-dimensional and Doppler echocardiography, histopathology and immunohistochemistry were performed in all mice and in vitro experiments conducted in primary cardiofibroblasts. The results showed that ADAM17 knockdown ameliorated while ADAM17 overexpression worsened cardiac dysfunction and cardiac fibrosis in diabetic mice. In addition, ADAM17 knockdown increased ACE2 while reduced AT1R expression in diabetic hearts. Mechanistically, ADAM17 knockdown decreased while ADAM17 overexpression increased cardiac fibroblast-to-myofibroblast transformation through regulation of TGF-β1/Smad3 signaling pathway. In conclusion, ADAM17 knockdown attenuates while ADAM17 overexpression aggravates cardiac fibrosis via regulating ACE2 shedding and myofibroblast transformation through TGF-β1/Smad3 signaling pathway in diabetic mice. Targeting ADAM17 may provide a promising approach to the prevention and treatment of cardiac fibrosis in DCM.

Profile of crosstalk between glucose and lipid metabolic disturbance and diabetic cardiomyopathy: Inflammation and oxidative stress

In recent years, the risk, such as hypertension, obesity and diabetes mellitus, of cardiovascular diseases has been increasing explosively with the development of living conditions and the expansion of social psychological pressure. The disturbance of glucose and lipid metabolism contributes to both collapse of myocardial structure and cardiac dysfunction, which ultimately leads to diabetic cardiomyopathy. The pathogenesis of diabetic cardiomyopathy is multifactorial, including inflammatory cascade activation, oxidative/nitrative stress, and the following impaired Ca2+ handling induced by insulin resistance/hyperinsulinemia, hyperglycemia, hyperlipidemia in diabetes. Some key alterations of cellular signaling network, such as translocation of CD36 to sarcolemma, activation of NLRP3 inflammasome, up-regulation of AGE/RAGE system, and disequilibrium of micro-RNA, mediate diabetic oxidative stress/inflammation related myocardial remodeling and ventricular dysfunction in the context of glucose and lipid metabolic disturbance. Here, we summarized the detailed oxidative stress/inflammation network by which the abnormality of glucose and lipid metabolism facilitates diabetic cardiomyopathy.

The Hippo-YAP pathway in various cardiovascular diseases: Focusing on the inflammatory response

The Hippo pathway was initially discovered in Drosophila melanogaster and mammals as a key regulator of tissue growth both in physiological and pathological states. Numerous studies depict the vital role of the Hippo pathway in cardiovascular development, heart regeneration, organ size and vascular remodeling through the regulation of YAP (yes-associated protein) translocation. Recently, an increasing number of studies have focused on the Hippo-YAP pathway in inflammation and immunology. Although the Hippo-YAP pathway has been revealed to play controversial roles in different contexts and cell types in the cardiovascular system, the mechanisms regulating tissue inflammation and the immune response remain to be clarified. In this review, we summarize findings from the past decade on the function and mechanism of the Hippo-YAP pathway in CVDs (cardiovascular diseases) such as myocardial infarction, cardiomyopathy and atherosclerosis. In particular, we emphasize the role of the Hippo-YAP pathway in regulating inflammatory cell infiltration and inflammatory cytokine activation.

Investigating Celastrol's Anti-DCM Targets and Mechanisms via Network Pharmacology and Experimental Validation

Methods

Data from TCMSP and GEO databases were utilized to identify targets for Celastrol on DCM. The relationship between the major targets and conventional glycolipid metabolism was obtained with Spearman correlation analysis. Experiments on animals were conducted utilizing healthy control (HC), low-dose Celastrol interventions (CL), and no intervention groups (NC), all of which had 8 SD rats in each group. To study alterations in signaling molecules, RT-PCR was performed.

Results

There were 76 common targets and 5 major targets for Celastrol-DCM. Celastrol have been found to regulate AGE-RAGE, TNF, MAPK, TOLL-like receptors, insulin resistance, and other signaling pathways, and they are closely linked to adipocytokines, fatty acid metabolism, glycolipid biosynthesis, and glycosylphosphati-dylinositol biosynthesis on DCM. These five major targets have been found to regulate these pathways. Experiments on rats indicated that P38 MAPK was considerably elevated in the cardiac tissue from rats in the CL and NC groups compared to the HC group, and the difference was statistically significant (P < 0.01). Significant differences were seen between the CL and NC groups in P38 MAPK levels, with a statistical significance level of less than 0.05.

Conclusion

Celastrol may play a role in reversing energy remodeling, anti-inflammation, and oxidative stress via modulating p38 protein expression in the MAPK pathway, which have been shown in the treatment of DCM.

Ca2+/Calmodulin-Dependent Protein Kinase II Regulation by Inhibitor of Receptor Interacting Protein Kinase 3 Alleviates Necroptosis in Glycation End Products-Induced Cardiomyocytes Injury

Necroptosisis a regulatory programmed form of necrosis. Receptor interacting protein kinase 3 (RIPK3) is a robust indicator of necroptosis. RIPK3 mediates myocardial necroptosis through activation of calcium/calmodulin-dependent protein kinase II (CaMKII) in cardiac ischemia-reperfusion (I/R) injury and heart failure. However, the exact mechanism of RIPK3 in advanced glycation end products (AGEs)-induced cardiomyocytes necroptosis is not clear. In this study, cardiomyocytes were subjected to AGEs stimulation for 24 h. RIPK3 expression, CaMKII expression, and necroptosis were determined in cardiomyocytes after AGEs stimulation. Then, cardiomyocytes were transfected with RIPK3 siRNA to downregulate RIPK3 followed by AGEs stimulation for 24 h. CaMKIIδ alternative splicing, CaMKII activity, oxidative stress, necroptosis, and cell damage were detected again. Next, cardiomyocytes were pretreated with GSK′872, a specific RIPK3 inhibitor to assess whether it could protect cardiomyocytes against AGEs stimulation. We found that AGEs increased the expression of RIPK3, aggravated the disorder of CaMKII δ alternative splicing, promoted CaMKII activation, enhanced oxidative stress, induced necroptosis, and damaged cardiomyocytes. RIPK3 downregulation or RIPK3 inhibitor GSK′872 corrected CaMKIIδ alternative splicing disorder, inhibited CaMKII activation, reduced oxidative stress, attenuated necroptosis, and improved cell damage in cardiomyocytes.

Diabetes leading to heart failure and heart failure leading to diabetes: epidemiological and clinical evidence

Type 2 diabetes mellitus (T2DM) is a risk factor that plays a major role in the onset of heart failure (HF) both directly, by impairing cardiac function, and indirectly, through associated diseases such as hypertension, coronary disease, renal dysfunction, obesity, and other metabolic disorders. In a population of HF patients, the presence of T2DM ranged from 20 to 40%, according to the population studied, risk factor characteristics, geographic area, and age, and it is associated with a worse prognosis. Finally, patients with HF, when compared with those without HF, show an increased risk for the onset of T2DM due to several mechanisms that predispose the HF patient to insulin resistance. Despite the epidemiological data confirmed the relationship between T2DM and HF, the exact prevalence of HF in T2DM comes from interventional trials rather than from observational registries aimed to prospectively evaluate the risk of HF occurrence in T2DM population. This review is focused on the vicious cycle linking HF and T2DM, from epidemiological data to prognostic implications.

HMGCS2 silencing attenuates high glucose-induced in vitro diabetic cardiomyopathy by increasing cell viability, and inhibiting apoptosis, inflammation, and oxidative stress

Diabetic cardiomyopathy (DCM) is a diabetic mellitus-related complications and progression of DCM may eventually lead to heart failure, while mechanisms related to DCM pathophysiology remain unclear. The study was undertaken to identify possible hub genes associated with DCM progression through bioinformatics analysis and to validate the role of 3-hydroxy-3-methylglutaryl-CoA synthase 2 (HMGCS2) in DCM progression using a cellular model of high glucose (HG)-induced DCM. The common differentially expressed genes (DEGs) between GSE173884 and GSE161827 were used for PPI network analysis. Our results identified 17 common DEGs between GSE173384 and GSE161827. Further analysis of the protein–protein interaction network identified nine hub genes and HMGCS2. The in vitro functional assays showed that HG induced up-regulation of HMGCS2, suppressed cardiomyocyte viability, enhanced apoptosis, inflammation, and oxidative stress of cardiomyocytes. Gain-of-function assays showed that HMGCS2 overexpression reduced cell viability, increased apoptosis, caspase-3/-9 activity, up-regulated interleukin (IL)-1β, IL-6 and tumor necrosis factor-α (TNF-α) expression, decreased superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase expression, increased malondialdehyde (MDA) content, and reactive oxygen species (ROS) level but inhibited total antioxidant activity, SOD activity, CAT activity, and glutathione content in cardiomyocytes. Rescue experiments demonstrated HMGCS2 silence attenuated HG-induced decrease in cardiomyocyte viability and increase in cardiomyocyte apoptosis, inflammation, and oxidative stress. All in all, our study identified HMGCS2 as a hub gene in DCM pathophysiology and further functional studies indicated that HMGCS2 may aggravate DCM progression by reducing cardiomyocyte viability, increasing cardiomyocyte apoptosis, and promoting inflammation and oxidative stress in cardiomyocytes.

Cardiac Hypertrophy: From Pathophysiological Mechanisms to Heart Failure Development

Cardiac hypertrophy develops in response to increased workload to reduce ventricular wall stress and maintain function and efficiency. Pathological hypertrophy can be adaptive at the beginning. However, if the stimulus persists, it may progress to ventricular chamber dilatation, contractile dysfunction, and heart failure, resulting in poorer outcome and increased social burden. The main pathophysiological mechanisms of pathological hypertrophy are cell death, fibrosis, mitochondrial dysfunction, dysregulation of Ca 2 + -handling proteins, metabolic changes, fetal gene expression reactivation, impaired protein and mitochondrial quality control, altered sarcomere structure, and inadequate angiogenesis. Diabetic cardiomyopathy is a condition in which cardiac pathological hypertrophy mainly develop due to insulin resistance and subsequent hyperglycaemia, associated with altered fatty acid metabolism, altered calcium homeostasis and inflammation. In this review, we summarize the underlying molecular mechanisms of pathological hypertrophy development and progression, which can be applied in the development of future novel therapeutic strategies in both reversal and prevention.

Cellular interplay between cardiomyocytes and non-myocytes in diabetic cardiomyopathy

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

Novel dual glucagon-like peptide-1/ glucose-dependent insulinotropic polypeptide receptor agonist attenuates diabetes and myocardial injury through inhibiting hyperglycemia, inflammation and oxidative stress in rodent animals

This study was aimed to evaluate the therapeutic effects and potent mechanisms of a novel GLP-1/GIP dual agonist on hyperglycemia and myocardial injury in diabetic mice. Novel dual-receptor agonists were designed and then evaluated via in vitro receptor activation assays. Acute hypoglycemic effects were assessed in diabetic mice induced by intraperitoneal injection of streptozotocin. Chronic effects of dual-receptor agonists on diabetes as well as diabetic cardiomyopathy were investigated in DCM model mice. Effects of the in vitro coculture of dual-receptor agonists with or without signaling pathway inhibitors on the cell viability and apoptosis of primary cardiomyocytes under a high-glucose state were assessed via MTT and western blotting methods to investigate the probable mechanism. AP5 exhibited balanced activities of dual-receptor activation in vitro and improved hypoglycemic ability in diabetic mice. Moreover, chronic treatment of AP5 achieved the prominently improved efficacy in reversing the deteriorative diabetic disorders and reducing the myocardial injury markers in DCM mice. Moreover, AP5 also inhibited the apoptosis and improved the survival rate of primary cardiomyocytes under a high-glucose state via increasing the expression levels of antiapoptotic proteins and inhibiting the release of apoptotic proteins, respectively, as well as activating the AMPK/PI3K/Akt signaling pathway. In conclusion, the dual GLP-1/GIP receptor agonist, AP5, can effectively improve diabetic symptoms and exert therapeutic effects on DCM via activating the AMPK/PI3K/Akt pathway, reducing the ROS production, oxidative stress and inflammatory markers in the rodent DCM model.Abbreviation: Diabetes mellitus, DM; diabetic cardiomyopathy, DCM; streptozotocin, STZ; glucagon-like peptide-1, GLP-1; malondialdehyde, MDA; glucose-dependent insulinotropic polypeptide, GIP; creatine kinase, CK; diabetic cardiomyopathy, DCM; serum superoxide dismutase; SOD; total superoxide disumutase, T-SOD; Methyl Thiazolyl Tetrazolium, MTT; lactate dehydrogenase; LDH; Adenosine Monophosphate-Activated Protein Kinase, AMPK; Dulbecco’s modified Eagle medium, DMEM; Fetal Bovine Serum, FBS; Reactive Oxygen Species, ROS; Glyceraldehyde-phosphate dehydrogenase, GAPDH; Surface Plasmon Resonance, SPR; Ethylene Diamine Tetraacetic Acid, EDTA; Interleukin-1β, IL-1β; Phosphoinositol 3-kinase, PI3K; Tumor necrosis factor, TNF-α; Renin-angiotensin-aldosterone system, RAAS; Glucose transporter, GLUT; Dipeptidyl peptidase-IV, DPP-IV; oxygen free radicals, OFR;

Elevated Serum Retinol Binding Protein 4 is Associated with the Risk of Diabetic Cardiomyopathy

Background

Retinol binding protein 4 (RBP4), a biomarker for insulin resistance in type 2 diabetes (DM), is increased in heart failure. This case-control study aims to determine the association between serum RBP4 levels and diabetic cardiomyopathy (DCM).

Methods

Demographic and clinical data were obtained from 245 DM patients and 102 non-diabetic controls. RBP4 levels were measured using ELISA. The association between RBP4 and DCM was evaluated using multivariate logistic regression and restricted cubic splines (RCS) in DM patients.

Results

We showed that serum RBP4 levels were higher in DCM patients than in DM patients without DCM or the controls. Multivariate analysis adjusted by age, gender, body mass index, diabetes duration, left ventricular ejection fraction, insulin treatment, triglycerides, low-density lipoprotein cholesterol, estimated glomerular filtration rate, diabetic retinopathy, diabetic nephropathy, diabetic neuropathy and log N-terminal proBNP showed a significant association between RBP4 and DCM (highest vs. lowest tertile OR 16.87, 95% CI: 6.58, 43.23, p < 0.001). RCS displayed a positive linear correlation between RBP4 levels and the risk of DCM in diabetes (p = 0.004). Adding RBP4 to a basic risk model for DCM improved the reclassification (Net reclassification index: 87.86%, 95% CI: 64.4%, 111.32%, p < 0.001).

Conclusions

The positive association between serum RBP4 and DCM suggested the role of RBP4 as a potential diagnostic biomarker for distinguishing DCM in patients with DM.

Chrysin Attenuates High Glucose-Induced BMSC Dysfunction via the Activation of the PI3K/AKT/Nrf2 Signaling Pathway

Purpose

High glucose environment in diabetes mellitus induces the dysfunction of bone marrow-derived mesenchymal stromal cells (BMSCs) and impairs bone regeneration. Chrysin is a natural polyphenol with outstanding anti-inflammation and anti-oxidation ability. However, whether and how chrysin affects BMSCs in high glucose conditions remain poorly understood. The present study aimed to explore the effects and underlying mechanisms of chrysin on the BMSCs exposed to high glucose environment.

Materials and Methods

Cell viability was detected by cell counting kit 8 assay and 5-ethynyl-2’-deoxyuridine staining, while cell apoptosis was determined through flow cytometry using Annexin V-FITC/PI kit. The oxidative stress in BMSCs was evaluated by detecting the reactive oxygen species production, malondialdehyde content, and superoxide dismutase activity. Alkaline phosphatase staining, Alizarin Red staining, and quantitative real-time PCR were performed to determine the osteogenic differentiation. Western blot was used to examine the expression of the PI3K/ATK/Nrf2 signaling pathway. Furthermore, chrysin was injected into calvarial defects of type 1 diabetic SD rats to assess its in vivo bone formation capability.

Results

Chrysin reduced oxidative stress, increased cell viability, and promoted osteogenic differentiation in BMSCs exposed to high glucose. Blocking PI3K/ATK/Nrf2 signaling pathway weakened the beneficial effects of chrysin, indicating that chrysin at least partly worked through the PI3K/ATK/Nrf2 pathway.

Conclusion

Chrysin can protect BMSCs from high glucose-induced oxidative stress via the activation of the PI3K/AKT/Nrf2 pathway, and promote bone regeneration in type 1 diabetic rats.

Delivery of astragalus polysaccharide by ultrasound microbubbles attenuate doxorubicin-induced cardiomyopathy in rodent animals

The aim of this study was to investigate the cardioprotective effects and probable mechanism of ultrasound-targeted microbubble destruction (UTMD) combined with astragalus polysaccharide (APS) on diabetic cardiomyopathy (DCM) model rats. The DCM rats with diabetes and cardiomyopathy were induced via chronic treatment of doxorubicin and then randomly divided into the (1) DCM model group; (2) APS microbubble group; (3) UTMDgroup; and (4) APS microbubbles combined with UTMD group. After 4-week intervention, the fasting blood glucose levels, body weight, %HbA1c level and glucose tolerance of DCM rats received combination therapy were significantly improved as compared with those of UTMD or saline-treated ones. Moreover, the heart/body weight ratio, and myocardial contractility were all improved after receiving combination therapy groups compared with others. In addition, significantly upregulated activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) as well as significantly downregulated malondialdehyde (MDA) levels were all observed in the ones received combined treatment compared to others. Furthermore, the lipid accumulation and the expression levels of inflammatory factors were all significantly down-regulated in those ones received combination therapy compared with others (all P < 0.05). Further pathological analysis demonstrated that combination therapy effectively ameliorated fibrosis and myocardial morphological changes of DCM rats via activating the upregulation of AMPK and PPAR-γ signaling pathway, and inhibiting NF-κB activity in myocardial tissues of DCM rats. In conclusion, APS microbubbles combined with UTMD effectively protect the myocardial injury of DCM rats via activating AMPK signaling pathway to alleviate inflammation response, fibrosis and oxidative stress in myocardial tissues.

MiR-29a regulates cardiomyocyte apoptosis by targeting Bak1 in diabetic cardiomyopathy

This study sought to investigate the association between microRNA-29a (miR-29a) and cardiomyocyte apoptosis in diabetic cardiomyopathy (DCM). DCM rat model was established by treating rats with streptozotocin (STZ), followed by injection of NC or miR-29a-3p mimics into the myocardium of rats. High glucose (HG)-treated H9c2 cells were transfected with NC and miR-29a-3p mimics. DCM rats presented elevated levels of blood glucose, HbA1c, and blood pressure and urine output and decreased body weight and cardiac contractile function after modeling. MiR-29a was lowly expressed in STZ-treated rats and HG-treated H9c2 cells. Upregulation of miR-29a improved cardiac structure and function and attenuated, alleviated myocardial histological abnormalities and fibrosis, and lowered cardiomyocyte apoptosis in DCM rats. Meanwhile, HG promoted H9c2 cell apoptosis, while miR-29a overexpression attenuated the function of HG. Compared with control group, the protein expression of Bax, cleaved-caspase3 and Bak1 in DCM and HG group were significantly upregulated, and the expression of Bcl-2 and Mcl-1 were downregulated, while miR-29a overexpression exerted opposite effect. Bioinformatics prediction method and western blot revealed that miR-29a directly targeted Bak1 and downregulated Bak1 expression. Overall, miR-29a regulated STZ- and HG-induced cardiomyocyte apoptosis by targeting Bak1, providing a novel understanding of the pathogenesis of DCM.