Diabetic cardiomyopathy: mechanisms and new treatment strategies targeting antioxidant signaling pathways

Rhein alleviates diabetic cardiomyopathy by inhibiting mitochondrial dynamics disorder, apoptosis and hypertrophy in cardiomyocytes

BACKGROUND

Diabetic cardiomyopathy (DCM) is a significant cardiovascular complication in diabetic patients, and treatment regimens are limited. Rhein, a compound extracted from the herb rhubarb, was investigated in this study for its efficacy on DCM and the potential mechanism.

METHODS

Streptozotocin-induced DCM mice, high-glucose (HG)-treated neonatal rat cardiomyocytes (NRCMs), and H9c2 cells with ClpP knockdown were used for the study. We performed phenotypic and molecular mechanistic studies using immunoblotting, quantitative polymerase chain reaction, transmission electron microscopy, cardiac echocardiography, and histopathological analysis.

RESULTS

Rhein improved the cardiac function and myocardial fibrosis, and decreased the cross-sectional area of cardiomyocytes in the DCM mice. It also improved mitochondrial dynamic disorder as evidenced by a decreased ratio of mitochondrial fission-related proteins p-Drp1S616/ Drp1 and increased expression of mitochondrial fusion proteins (Opa1, Mfn1 and Mfn2). Rhein mitigated apoptosis as indicated by decreased apoptosis-related proteins (caspase 9, cleaved-caspase 3 and Bax) and increased anti-apoptosis protein Bcl2 in the heart tissue of DCM mice. Upregulations of cardiac hypertrophy associated genes (ANP, BNP and β-MHC) were significantly inhibited by Rhein treatment. In addition, the level of ClpP, a mitochondrial protease, was increased in DCM, but was normalized by Rhein treatment. However, ClpP knockdown exacerbated cardiomyocyte injury in the presence or absence of HG in H9c2 cells, indicating that a normal level of ClpP is essential for cardiomyocytes to survive.

CONCLUSIONS

Our results suggest that Rhein protects DCM by ameliorating mitochondrial dynamics disorder, inhibiting cardiomyocyte apoptosis, and myocardial hypertrophy. These protective effects of Rhein may be mediated by preventing ClpP upregulation.

New insights into diabetes-induced cardiac pathology

Individuals with diabetes have an elevated risk of heart disease, and there is a significant clinical need for evidence-based treatments. Heart disease in diabetes manifests as a distinct cardiopathology, with cardiac structural and functional remodeling underlying increased susceptibility to cardiac dysfunction and arrhythmias. An understanding of the mechanisms associated with cardiac vulnerability in diabetes is incomplete, but recent studies have advanced new insights into the roles of metabolic disturbances, gene dysregulation and epicardial adipose influence. This perspective article highlights these three promising new developments in proposed mechanisms, and discusses exciting advances in cardiac-targeting for potential treatment of diabetic heart disease.

A comprehensive review on diabetic cardiomyopathy (DCM): histological spectrum, diagnosis, pathogenesis, and management with conventional treatments and natural compounds

Diabetic complications are among the most pressing health issues currently. Cardiovascular problems, particularly diabetic cardiomyopathy (DCM), are responsible for almost 80% of diabetic deaths. Because of the increasing prevalence of diabetes and the increased threat of death from its consequences, researchers are searching for new pharmaceutical targets to delay or cure it. Currently, there are a few medicines available for the treatment of DCM, some of which have serious side effects. To address this issue, researchers are focusing on natural products. Thus, in this review, we discuss the prevalence, incidence, risk factors, histological spectrum, diagnosis, pathogenic pathways of DCM, genetic and epigenetic mechanisms involved in DCM, the current treatments, and the beneficial effects of natural product-based therapeutics. Natural treatments range from single doses to continuous regimens lasting weeks or months. Flavonoids are the largest class of natural compounds reported for the treatment of DCM. Natural regimens may cover the way for new treatment strategies for DCM for being multi-target agents in the treatment of DCM, with the ability to play a variety of functions via distinct signaling pathways.

Integrated meta-analysis and network pharmacology analysis: evaluation of Zhigancao decoction as treatment for diabetic cardiomyopathy

Background

Zhigancao Decoction (ZGCD) is derived from "Treatise on Febrile Diseases" and is traditionally prescribed for treating a variety of cardiovascular conditions. As of now, there are no data to support its use as a treatment for diabetic cardiomyopathy (DCM) and the mechanism behind the effect is unclear as well. In the present study, clinical evidence for the efficacy of ZGCD in patients with DCM was examined using a meta-analysis and its underlying anti-DCM molecular mechanisms were explored via network pharmacology.

Methods

The current study utilized an extensive search strategy encompassing various domestic and foreign databases databases to retrieve pertinent articles published up to June 2024. In light of this, a thorough evaluation of the benefits and safety of Zhigancao decoction (ZGCD) was conducted in this study using RevMan and Stata. Subsequently, a number of active compounds and target genes for ZGCD were gathered from the TCMSP and BATMAN-TCM databases, while the main targets for DCM were obtained from databases such as GenCards, OMIM, TTD, and DrugBank. To select core genes, protein-protein interaction networks were generated using the STRING platform, and enrichment analyses were completed using the Metascape platform.

Results

Meta-analysis results were ultimately derived from 9 studies involving 661 patients in total. In comparison with WM therapy alone, the pooled results showed that ZGCD significantly enhanced overall effectiveness. Additionally, the utilization of ZGCD was leading to a reduction in LVEDV, LVESV and LVDD, also a greater increase in LVEF. Meanwhile, the utilization of ZGCD during intervention was more effective in reducing SBP, and DBP. In addition, the ZGCD showed potential in reducing the occurrence of adverse events. In the context of network pharmacology, five constituents of ZGCD-namely lysine, quercetin, gamma-aminobutyric acid, stigmasterol, and beta-sitosterol-are posited to exert anti-diabetic cardiomyopathy (anti-DCM) effects through interactions with the molecular targets ASS1, SERPINE1, CACNA2D1, AVP, APOB, ICAM1, EGFR, TNNC1, F2, F10, IGF1, TNNI2, CAV1, INSR, and INS. The primary mechanisms by which ZGCD may achieve its anti-DCM effects are likely mediated via the AGEs/RAGE signaling pathway, as well as through pathways related to lipid metabolism and atherosclerosis.

Conclusion

In comparison to WM therapy alone, ZGCD demonstrates greater efficacy and safety in the management of DCM. ZGCD not only significantly reduces blood pressure, but also enhances cardiac function while producing fewer adverse effects. The therapeutic effects of ZGCD on DCM can likely be ascribed to its capacity to modulate the AGEs-RAGE signaling pathway, as well as its efficacy in enhancing lipid metabolism and mitigating atherosclerosis.

Systematic Review Registration

identifier (INPLASY202430133).

Supplementation with aspalathin and sulforaphane protects cultured cardiac cells against dyslipidemia-associated oxidative damage

Dyslipidemia is a prominent pathological feature responsible for oxidative stress-induced cardiac damage. Due to their high antioxidant content, dietary compounds, such as aspalathin and sulforaphane, are increasingly explored for their cardioprotective effects against lipid-induced toxicity. Cultured H9c2 cardiomyoblasts, an in vitro model routinely used to assess the pharmacological effect of drugs, were pretreated with the dietary compounds, aspalathin (1 μM) and sulforaphane (10 μM) before exposure to palmitic acid (0.25 mM) to induce lipidemic-related complications. The results showed that both aspalathin and sulforaphane enhanced cellular metabolic activity and improved mitochondrial respiration correlating with improved mRNA expression of genes involved in mitochondrial function, including uncoupling protein 2, peroxisome proliferator-activated receptor, gamma coactivator 1-alpha, nuclear respiratory factor 1, and ubiquinol-cytochrome c reductase complex assembly factor 1. Beyond attenuating lipid peroxidation, the dietary compounds also suppressed intracellular reactive oxygen species and enhanced antioxidant responses, including the mRNA expression of nuclear factor erythroid 2-related factor 2. These envisaged benefits were associated with decreased cellular apoptosis. This preclinical study supports and warrants further investigation into the potential benefits of these dietary compounds or foods rich in aspalathin or sulforaphane in protecting against lipid-induced oxidative damage within the myocardium.

Deficiency in nucleoside diphosphate kinase B leads to endothelial activation of the hexosamine biosynthesis pathway and cardiac dysfunction

BACKGROUND

Nucleoside diphosphate kinase B (NDPKB) deficiency in endothelial cells (ECs) promotes the activation of the hexosamine biosynthesis pathway (HBP), leading to vascular damage in the retina. The aim of this study was to investigate the consequences of NDPKB deficiency in the mouse heart.

METHODS

NDPKB deficient mice were used in the study. Echocardiography was employed to assess cardiac function in vivo. Characterization of contractility in hiPSC-derived cardiomyocytes (hiPSC-CMs) was measured with the IonOptix contractility system. Immunoblotting and immunofluorescence were carried out to analyze the expression and localization of proteins in cultured cells and left ventricles (LVs).

RESULTS

NDPKB deficient mice displayed impaired glucose tolerance and increased heart weight compared to controls. Echocardiographic analysis revealed an increase in the diastolic diameter of the left ventricular posterior wall (LVPW), a decrease in the early diastolic mitral valve E and E' wave, and in the ratios of E/A and E'/A' in NDPKB deficient hearts, suggesting cardiac hypertrophy and diastolic dysfunction. In line with cardiac dysfunction, the phosphorylation of myocardial phospholamban (PLN) and the expression of sarcoplasmic/endoplasmic reticulum Ca2+-ATPase 2 (SERCA2) in the NDPKB deficient LVs were significantly reduced. Moreover, the accumulation of collagen, fibronectin as well as the upregulation of transforming growth factor β (TGF-β), were detected in NDPKB deficient LVs. In addition, activation of the HBP and its downstream O-GlcNAc cycle was observed in the LVs and cardiac ECs (CECs) isolated from the NDPKB-/- mice. Furthermore, a bipolar O-GlcNAc regulation was identified in CMs. O-GlcNAc was decreased in NDPKB-depleted CMs, while conditioned medium from NDPKB-depleted ECs significantly increased O-GlcNAc levels, along with contractile and relaxation dysfunction of the hiPSC-CMs, which was attenuated by inhibiting endothelial HBP activation.

CONCLUSIONS

Deficiency in NDPKB leads to endothelial activation of the HBP and cardiac dysfunction. Our findings may highlight the crucial role of proper endothelial HBP in maintaining cardiovascular homeostasis.

Luteolin alleviates diabetic cardiac injury related to inhibiting SHP2/STAT3 pathway

Diabetic cardiomyopathy, a heart disease resulting from diabetes mellitus, inflicts structural and functional damage to the heart. Recent studies have highlighted the potential role of luteolin, a flavonoid, in mitigating diabetic cardiovascular injuries. The Src homology 2-containing protein tyrosine phosphatase 2 (SHP2) is implicated in exacerbating diabetes- and obesity-related complications. Interestingly, luteolin has been shown to inhibit protein tyrosine phosphatases, but it's unclear how SHP2 relates to luteolin's protective effects against diabetic heart disease. Here, we hypothesized that the inhibition of SHP2 signaling could play a role in luteolin's protective action against diabetic heart injury. Diabetes was induced in male Sprague-Dawley rats through a high-fat diet followed by a single intraperitoneal dose of streptozotocin (30 mg/kg). Five weeks post-diabetes induction, these rats were intraperitoneally injected with luteolin at varying doses (5, 10, 20 mg/kg) every other day for an additional 5 weeks. Then cardiac function was assessed, and hearts were isolated for further analysis. We found that luteolin notably improved cardiac function, inhibited cardiac hypertrophy and fibrosis, reduced levels of inflammatory factors and reactive oxygen species, and activated superoxide dismutase. Importantly, luteolin treatment also reduced the expression of SHP2 and phosphorylated signal transducer and activator of transcription 3 (STAT3) in a dose-dependent manner. These findings suggest that luteolin protects the diabetic heart against inflammation, oxidative stress, hypertrophy, and fibrosis, which may relate to down-regulating cardiac SHP2/STAT3 signaling.

Resveratrol Attenuates Fibrosis and Alters Signaling Pathways in Diabetic Cardiac and Skeletal Muscles and Adipose Tissue Without Reversing Structural Damage

Resveratrol (RSV) improves metabolic functions, but its tissue-specific effects on diabetes remain unclear. This study investigated RSV's impact on molecular pathways in an experimental model of diabetes in cardiac and skeletal muscles and adipose tissue. Wistar rats were assigned to control (C), control treated with RSV (RC), diabetic (D), and diabetic treated with RSV (RD). Diabetes was induced using streptozotocin and nicotinamide, and RSV was administered for six weeks. In diabetic rats, RSV treatment significantly reduced collagen accumulation in cardiac and skeletal muscle tissues compared to untreated diabetic controls, although it did not restore muscle mass. Adipose tissue in diabetic rats exhibited a significant reduction of 3.4 times in collagen levels following RSV treatment. However, this reduction was not associated with any measurable improvement in tissue function. In cardiac tissue, RSV downregulated phosphorylated protein kinase B (AKT)/AKT and phosphorylated ribosomal protein S6 (rpS6)/rpS6 while mammalian target of rapamycin (mTOR) activity remained unchanged. In skeletal muscle, RSV suppressed rpS6 phosphorylation without affecting (mTOR) signaling. RSV enhanced mTOR and Beclin-1 expression in adipose tissue, though metabolic dysfunction persisted. RSV reduced receptors for advanced glycation end-product expression in all tissues, indicating the modulation of hyperglycemia-driven pathways. RSV improved fibrosis and signaling pathways but failed to reverse abnormal tissue growth patterns, including cardiac hypertrophy, skeletal muscle atrophy, and adipose tissue atrophy.

Roxadustat improves diabetic myocardial injury by upregulating HIF-1α/UCP2 against oxidative stress

BACKGROUND

Diabetes mellitus (DM), characterized by hyperglycemia, is intricately linked with cardiovascular complications. Hyperglycemia induces oxidative stress, compromising mitochondria energy metabolism disturbances, leading to cardiomyocyte hypoxia and dysregulation of hypoxia-inducible factor-1α (HIF-1α), thereby exacerbating diabetic myocardial injury. Roxadustat (FG-4592), as an inhibitor of HIF-PHD, reduces HIF-1α degradation and regulates the transcription and function of downstream target genes. This study explores the protective effect of FG-4592 on the diabetic myocardium and further investigates the specific mechanisms responsible for this action.

METHODS

We established diabetic myocardial injury mice and high glucose-induced rat cardiomyocyte models, administered FG-4592 pretreatment to clarify the protective effects and related mechanisms of FG-4592 on diabetic myocardial injury by detecting changes in oxidative stress, mitochondrial function, and related pathways.

RESULTS

FG-4592 demonstrated cardioprotective effects in diabetic mice by regulating mitochondrial structure and function, as well as maintaining oxidative stress balance in the myocardium. It stabilized HIF-1α, activated UCP2, and enhanced the PI3K/AKT/Nrf2 pathway, reducing mitochondrial superoxide production, improving mitochondrial respiratory potential, and modulating oxidative stress markers in high glucose-induced cardiomyocytes.

CONCLUSIONS

FG-4592 exerts protective effects against diabetic myocardial injury by reducing oxidative stress. The mechanism is linked with the upregulation of HIF-1α and UCP2, which subsequently activate the PI3K/AKT/Nrf2 signaling pathway.

Ferroptosis: mechanism and role in diabetes-related cardiovascular diseases

Cardiovascular diseases represent the principal cause of death and comorbidity among people with diabetes. Ferroptosis, an iron-dependent non-apoptotic regulated cellular death characterized by lipid peroxidation, is involved in the pathogenesis of diabetic cardiovascular diseases. The susceptibility to ferroptosis in diabetic hearts is possibly related to myocardial iron accumulation, abnormal lipid metabolism and excess oxidative stress under hyperglycemia conditions. Accumulating evidence suggests ferroptosis can be the therapeutic target for diabetic cardiovascular diseases. This review summarizes ferroptosis-related mechanisms in the pathogenesis of diabetic cardiovascular diseases and novel therapeutic choices targeting ferroptosis-related pathways. Further study on ferroptosis-mediated cardiac injury can enhance our understanding of the pathophysiology of diabetic cardiovascular diseases and provide more potential therapeutic choices.

Adeno-Associated Viruses as Gene Delivery Tools for Diabetic Heart Disease and Failure: Key Considerations for Clinicians and Preclinical Researchers

Diabetes is becoming more common worldwide, and people with diabetes are twice as likely to experience heart problems compared to those without diabetes. These cardiovascular complications are the foremost cause of mortality among people with diabetes. A specific form of heart failure known as "diabetic cardiomyopathy" can develop in individuals with diabetes. There are no treatments specifically approved for diabetic cardiomyopathy. Ongoing research is exploring innovative treatments, including the development of gene therapy techniques (e.g., adeno-associated viral vectors) designed to target specific molecular pathways affected in the disease. Here, we discuss the progress, challenges, and experimental considerations of gene therapy for the diabetic heart.

TiOx(OH)4-2x Nanosheets with Catalytic Antioxidative Activity Alleviate Oxidative Injury in Diabetic Cardiomyopathy

Diabetic cardiomyopathy (DCM) is one of the most lethal complications of diabetes and is induced by the overproduction of reactive oxygen species (ROS) in cardiomyocytes due to sustained high glucose levels, leading to cardiac oxidative damage and final sudden death. Drugs and antioxidants currently applied to the clinical therapy of DCM fail to scavenge ROS efficiently, resulting in compromised therapeutic efficacy. Herein, a nanocatalytic antioxidative therapeutic strategy is proposed for DCM treatment. A two-dimensional TiOx(OH)4-2x nanosheet platform has been constructed with efficient ROS-scavenging activity, which can catalyze antioxidation reaction through redox cycling between TiIV/TiIII accompanied by inner-sphere two-electron transfer. Cellular experiments demonstrate that the TiOx(OH)4-2x nanosheet can not only protect cardiomyocytes from oxidative damage induced by a high glucose environment but also alleviate inflammation to further protect cardiomyocytes from inflammatory injury. The in vivo animal model confirms that the nanosheet alleviates myocardial oxidative injury and recovers cardiac function. Such a nanocatalytic antioxidation strategy is expected to provide a feasible approach for treating DCM and other cardiovascular diseases.

Sodium-dependent glucose transporter 2 inhibitors improve heart function in patients with type 2 diabetes and heart failure

This article discusses the study by Grubić Rotkvić et al on the mechanisms of action of sodium-glucose cotransporter 2 inhibitors (SGLT2i) in patients with type 2 diabetes mellitus (T2DM) and heart failure (HF). T2DM and HF are highly comorbid, with a significantly increased prevalence of HF in patients with T2DM. SGLT2i exhibit potential in reducing hospitalization rates for HF and cardiovascular mortality through multiple mechanisms, including improving blood glucose control, promoting urinary sodium excretion, reducing sympathetic nervous system activity, lowering both preload and afterload on the heart, alleviating inflammation and oxidative stress, enhancing endothelial function, improving myocardial energy metabolism, and stabilizing cardiac ion homeostasis. Further research and clinical practice will help optimize the use of SGLT2i in HF patients.

Empagliflozin in diabetic cardiomyopathy: elucidating mechanisms, therapeutic potentials, and future directions

Diabetic cardiomyopathy (DCM) represents a significant health burden, exacerbated by the global increase in type 2 diabetes mellitus (T2DM). This condition contributes substantially to the morbidity and mortality associated with diabetes, primarily through myocardial dysfunction independent of coronary artery disease. Current treatment strategies focus on managing symptoms rather than targeting the underlying pathophysiological mechanisms, highlighting a critical need for specific therapeutic interventions. This review explores the multifaceted role of empagliflozin, a sodium-glucose cotransporter 2 (SGLT-2) inhibitor, in addressing the complex etiology of DCM. We discuss the key mechanisms by which hyperglycemia contributes to cardiac dysfunction, including oxidative stress, mitochondrial impairment, and inflammation, and how empagliflozin mitigates these effects. Empagliflozin's effects on reducing hospitalization for heart failure and potentially lowering cardiovascular mortality mark it as a promising candidate for DCM management. By elucidating the underlying mechanisms through which empagliflozin operates, this review underscores its therapeutic potential and paves the way for future research into its broader applications in diabetic cardiac care. This synthesis aims to foster a deeper understanding of DCM and encourage the integration of empagliflozin into treatment paradigms, offering hope for improved outcomes in patients suffering from this debilitating condition.

Critical Appraisal of Pharmaceutical Therapy in Diabetic Cardiomyopathy-Challenges and Prospectives

Diabetes mellitus (DM) is a multifaceted disorder with a pandemic spread and a remarkable burden of cardiovascular mortality and morbidity. Diabetic cardiomyopathy (DBCM) has been increasingly recognized as the development of cardiac dysfunction, which is accompanied by heart failure (HF) symptoms in the absence of obvious reasons like ischemic heart disease, hypertension, or valvulopathies. Several pathophysiological mechanisms have been proposed, including metabolic disorders (e.g., glycation products), oxidative stress, low-grade inflammation, mitochondrial dysfunction, etc., which should guide the development of new therapeutic strategies. Up to now, HF treatment has not differed between patients with and without diabetes, which limits the expected benefits despite the high cardiovascular risk in the former group. However, DBCM patients may require different management, which prioritize anti-diabetic medications or testing other novel therapies. This review aims to appraise the challenges and prospectives of the individualized pharmaceutical therapy for DBCM.

Diabetic Cardiomyopathy: An Update on Emerging Pathological Mechanisms

Diabetic Cardiomyopathy (DCM) is a notable consequence of diabetes mellitus, distinguished by cardiac dysfunction that occurs separately from coronary artery disease or hypertension. A recent study has revealed an intricate interaction of pathogenic processes that contribute to DCM. Important aspects involve the dysregulation of glucose metabolism, resulting in heightened oxidative stress and impaired mitochondrial function. In addition, persistent high blood sugar levels stimulate inflammatory pathways, which contribute to the development of heart fibrosis and remodelling. Additionally, changes in the way calcium is managed and the presence of insulin resistance are crucial factors in the formation and advancement of DCM. This may be due to the involvement of many molecular mechanistic pathways such as NLRP3, NF-κB, PKC, and MAPK with their downstream associated signaling pathways. Gaining a comprehensive understanding of these newly identified pathogenic pathways is crucial in order to design precise therapy approaches that can enhance the results for individuals suffering from diabetes. In addition, this review offers an in-depth review of not just pathogenic pathways and molecular mechanistic pathways but also diagnostic methods, treatment options, and clinical trials.

Effects of Exercise Training on Cardiac Mitochondrial Functions in Diabetic Heart: A Systematic Review

A diabetic heart is characterized by fibrosis, autophagy, oxidative stress, and altered mitochondrial functions. For this review, three databases (PubMed, EMBASE, and Web of Science) were searched for articles written in English from September 2023 to April 2024. Studies that used exercise training for at least 3 weeks and which reported positive, negative, or no effects were included. The CAMARADES checklist was used to assess the quality of the included studies, and ten studies (CAMARADES scores 4-7/10) were included. Nine studies showed that exercise training improved cardiac mitochondrial oxidative phosphorylation by decreasing ROS, increasing electron transport chain activity, and enhancing the production of ATP. Eight studies indicated that exercise training ameliorated mitochondrial biogenesis by increasing the levels of AMPK, PGC-1α, Akt, Irisin, and Sirtuin-III. Moreover, four studies focused on mitochondrial dynamics and concluded that exercise training helped decrease the levels of mitochondrial fission factor and dynamin-related protein- 1. Finally, six studies revealed improvements in mitochondrial physiological characteristics such as size, potential, and permeability. Our findings demonstrate the beneficial effects of exercise training on cardiac mitochondrial function in diabetic hearts. Exercise training improves cardiac mitochondrial physiological characteristics, oxidative phosphorylation, biogenesis, and dynamics.

Astaxanthin protects fludrocortisone acetate-induced cardiac injury by attenuating oxidative stress, fibrosis, and inflammation through TGF-β/Smad signaling pathway

Hypertensive rats serve as a good experimental model for studying the pathophysiology of cardiac hypertrophy and remodeling leading to heart failure. In this study, we aimed to analyze the effect of astaxanthin and possible mechanisms involved in alleviating oxidative stress, fibrosis and inflammation that triggers cardiac remodeling using male uninephrectomized Long Evans rats. Cardiac hypertrophy and hypertension were induced in rats termed as 'FCA-Salt rats' by an oral administration of fludrocortisone acetate (FCA) and 1 % NaCl in drinking water. Biochemical assays showed that FCA-Salt rats exhibited an upregulation of oxidative stress markers AOPP, MDA and downregulation of NO in heart and kidney, which was reversed by astaxanthin treatment. Astaxanthin further regularized the reduced activities of antioxidant enzymes GSH, SOD and CAT in these tissues. ELISA revealed that astaxanthin significantly reduced the inflammatory response by reducing the elevated levels of IL-1β, IL-17a, and TNF-α and pro-fibrotic marker TGF-β1 in plasma. Real-time qPCR depicted an upregulation of TNF-α, IL-1β, IL-6, IL-17A as well as signaling molecules TGF-β1, Smad2 and Smad3 in heart of FCA-Salt rats, which was reduced significantly by astaxanthin. Sirius red staining showed that the cardiac and renal fibrosis was significantly improved by astaxanthin treatment. Together, our results suggest that astaxanthin treatment is beneficial in protecting cardio-renal damage in hypertension through TGF-β/Smad signaling pathway, hence, this molecule may be considered for the maintenance of cardio-renal health.

TRPM2 knockdown attenuates myocardial apoptosis and promotes autophagy in HFD/STZ-induced diabetic mice via regulating the MEK/ERK and mTORC1 signaling pathway

Diabetic cardiomyopathy (DCM) is a major complication of diabetes. Transient receptor potential melastatin 2 (TRPM2) activity increases in diabetic oxidative stress state, and it is involved in myocardial damage and repair. We explore the protective effect of TRPM2 knockdown on the progression of DCM. A type 2 diabetes animal model was established in C57BL/6N mice by long-term high-fat diet (HFD) feeding combined with a single injection of 100-mg/kg streptozotocin (STZ). Genetic knockdown of TRPM2 in heart was accomplished by the intravenous injection via the tail vein of adeno-associated virus type 9 carrying TRPM2 shRNA. Neonatal rat ventricular myocytes was exposed to 45 mM of high-glucose (HG) stimulation for 72 h in vitro to mimic the in vivo conditions. Western blot, real-time quantitative PCR (RT-qPCR), immunohistochemistry and fluorescence, electron, CCK-8, and flow cytometry were used to evaluate the phenotype of cardiac inflammation, fibrosis, apoptosis, and autophagy. Mice with HFD/STZ-induced diabetes exhibited systolic and diastolic dysfunction, as demonstrated by increased myocardial apoptosis and autophagy inhibition in the heart. Compared to control group, the protein expression of TRPM2, bax, cleaved caspase-3, and P62 was significantly elevated, and the protein expression of bcl-2 and LC3-II was significantly decreased in the myocardial tissues of the HFD/STZ-induced diabetes group. Knockdown of TRPM2 significantly reversed the HFD/STZ-induced myocardial apoptosis and autophagy inhibition. TRPM2 silencing attenuated HG-induced apoptosis and autophagy inhibition in primary cardiomyocytes via regulating the MEK/ERK mTORC1 signaling pathway. TRPM2 knockdown attenuates hyperglycemia-induced myocardial apoptosis and promotes autophagy in HFD/STZ-induced diabetic mice or HG-stimulated cardiomyocytes via regulating the MEK/ERK and mTORC1 signaling pathway.

Mechanistic insights and therapeutic potential of astilbin and apigenin in diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) represents a critical complication of Diabetes mellitus (DM), characterized by structural and functional changes in the myocardium independent of coronary artery disease or hypertension. Emerging evidence highlights the significant roles of phytochemicals, particularly astilbin and apigenin, in modulating key molecular pathways implicated in DCM. This review synthesizes current mechanistic insights and therapeutic potential of these compounds, focusing on their interactions with AMP-activated protein kinase (AMPK), peroxisome proliferator-activated receptors (PPARs), O-linked N-acetylglucosamine (O-GlcNAc), sodium-glucose co-transporter 2 (SGLT2), protein kinase C (PKC), nuclear factor kappa B (NF-κB), mitogen-activated protein kinase (MAPK), and c-Jun N-terminal kinase (JNK) pathways. Astilbin and apigenin have demonstrated the ability to improve cardiac function, mitigate oxidative stress, and reduce inflammatory responses in diabetic conditions. By activating AMPK and PPARs, these flavonoids enhance glucose uptake and fatty acid oxidation, contributing to improved metabolic homeostasis. Their inhibition of O-GlcNAcylation, SGLT2 activity, and PKC signaling further attenuates hyperglycemia-induced cellular damage. Additionally, suppression of NF-κB, MAPK, and JNK pathways by astilbin and apigenin results in reduced pro-inflammatory cytokine production and apoptotic cell death. Collectively, these interactions position astilbin and apigenin as promising therapeutic agents for ameliorating DCM, offering novel avenues for treatment strategies aimed at modulating multiple pathogenic pathways.

Single-cell transcriptome sequencing revealed the metabolic changes and microenvironment changes of cardiomyocytes induced by diabetes

PURPOSE

Diabetes is a chronic metabolic disorder characterized by elevated blood glucose levels. This study aimed to analyze the changes underlying heterogeneities and communication properties of CMs in diabetes mellitus (DM).

METHODS

GSE213337 dataset was retrieved from NCBI Gene Expression Omnibus, containing the single-cell RNA sequencing data of hearts from the control and streptozotocin-induced diabetic mice. GSEA and GSVA were used to explore the function enrichment of DEGs in CM. Cell communication analysis was carried out to study the altered signals and significant ligand-receptor interactions.

RESULTS

Seventeen cell types were identified between DM and the controls. The increasing ratio of CM suggested the occurrence of diabetes induces potential pathological changes of CM proliferation. A total of 1144 DEGs were identified in CM. GSEA and GSVA analysis indicated the enhancing lipid metabolism involving in DM. The results of cell communication analysis suggested that high glucose activated the ability of CM receiving fibroblast and LEC, while inhibited the capacity of receiving ECC and pericyte. Furthermore, GAS and ANGPTL were significantly decreased under DM, which was consistent with the results of GSEA and GSVA. Finally, the ligand-receptor interactions such as vegfc-vegfr2, angptl1 were changes in CM.

CONCLUSIONS

The CM showed the significant heterogeneities in DM, which played an important role in myocardial fibrosis induce by hyperglycemia.

Impact of Chronic Consumption of Herbal Rooibos on Cardiovascular Function in Adults with Cardiovascular Risk

The prevalence of cardiovascular disease (CVD) has increased in South Africa, emphasizing the importance of prevention strategies. This study used echocardiography to investigate the impact of Rooibos on cardiovascular function in those at risk of CVD. This research aims to contribute to understanding its effects on reducing cardiovascular risk factors. The study design involved a 12-week randomized, parallel, double-blinded, placebo-controlled dietary intervention trial using capsules containing standardized water-soluble extracts of green and traditional fermented Rooibos alongside a placebo control. Echocardiography was incorporated as a diagnostic imaging tool to assess cardiac function in the participant cohort. Aorta (AO) dimensions showed no significant change in any intervention group. Left atrium (LA) reduced in size from 3.832 ± 0.071 cm to 3.675 ± 0.067 cm (P = 0.01). There was no significant change in LA/AO ratio in any intervention group. Interventricular septum diameter in the placebo group decreased from 1.334 ± 0.030 cm to 1.250 ± 0.025 cm (P = 0.002), with no significance in fermented Rooibos, while green Rooibos resulted in a decrease from 1.282 ± 0.036 cm to 1.186 ± 0.029 cm (P = 0.002). Left ventricle posterior wall (LVPW) showed no significant changes in any of the intervention group. The left ventricle mass in the placebo and green Rooibos groups demonstrated no significance changes, while fermented Rooibos caused a decrease from 204.102 ± 7.102 g to 191.394 ± 6.707 g (P = 0.015). The phytochemical bioactive components, such as the polyphenolic antioxidants present in green and fermented Rooibos, improved cardiovascular function. This study confirms the effectiveness of echocardiography as imaging tool for assessing cardiac function in this particular population. Regular Rooibos consumption may offer promising therapeutic benefits for preventing and managing CVD risk.

Investigation of crucial genes and mitochondrial function impairment in diabetic cardiomyopathy

BACKGROUND

Diabetic cardiomyopathy (DCM) is a special type of cardiovascular disease, termed as a situation of abnormal myocardial structure and function that occurs in diabetic patients. However, the most fundamental mechanisms of DCM have not been fully explicated, and useful targets for the therapeutic strategies still need to be explored.

METHODS

In the present study, we combined bioinformatics analysis and in vitro experiments throughout the process of DCM. Differentially Expressed Genes (DEGs) analysis was performed and the weighted gene co-expression network analysis (WGCNA) was constructed to determine the crucial genes that were tightly connected to DCM. Additionally, Functional enrichment analysis was conducted to define biological pathways. To identify the specific molecular mechanism, the human cardiomyocyte cell line (AC16) was stimulated by high glucose (HG, 50 mM D-glucose) and used to imitate DCM condition. Then, we tentatively examined the effect of high glucose on cardiomyocytes, the expression levels of crucial genes were further validated by in vitro experiments.

RESULTS

Generally, NPPA, IGFBP5, SERPINE1, and C3 emerged as potential therapeutic targets. Functional enrichment analysis performed by bioinformatics indicated that the pathogenesis of DCM is mainly related to heart muscle contraction and calcium (Ca2+) release activation. In vitro, we discovered that high glucose treatment induced cardiomyocyte injury and exacerbated mitochondrial dysfunction remarkably.

CONCLUSION

Our research defined four crucial genes, as well as determined that mitochondrial function impairment compromises calcium homeostasis ultimately resulting in contractile dysfunction is a central contributor to DCM progression. Hopefully, this study will offer more effective biomarkers for DCM diagnosis and treatment.

Regulatory T cells protect against diabetic cardiomyopathy in db/db mice

AIMS/INTRODUCTION

Regulatory T cells (Tregs) have protected against many cardiovascular diseases. This study was intended to explore the effect of Tregs on diabetic cardiomyopathy (DCM) using a db/db mouse model.

MATERIALS AND METHODS

Eight-week-old male db/db mice were randomly divided into four groups: the control group, administered 200 μL phosphate-buffered saline; the small-dose Treg group, administered 105 Tregs; the large-dose Treg group, administered 106 Tregs; and the PC group, administered 100 μg anti-CD25 specific antibody (PC61) and 106 Tregs. After 12 weeks, mice were euthanized. Transthoracic echocardiography was carried out at the beginning and end of the experiment. Relevant basic experiments to evaluate the effects of Tregs on DCM were carried out.

RESULTS

Echocardiography showed that the impaired diastolic and systolic functions were significantly improved in mice administered large-dose Tregs. Large-dose Tregs significantly ameliorated myocardial hypertrophy and fibrosis, and decreased hypertrophic gene expression and collagen deposition. The protective effects of Tregs on diabetic hearts were associated with decreased oxidative stress, inflammatory response and apoptosis. In addition, Tregs promoted the activation of the phosphatidylinositol 3-kinase-protein kinase B signaling pathway, whereas they inhibited extracellular signal-regulated kinase 1/2 and Jun N-terminal kinase phosphorylation, which might be responsible for the cardioprotective role of Tregs against DCM.

CONCLUSIONS

Tregs ameliorated myocardial hypertrophy and fibrosis, improved cardiac dysfunction, and protected against DCM progression in db/db mice. The mechanisms involved a decrease of inflammatory response, oxidative stress and apoptosis, which might be mediated by phosphatidylinositol 3-kinase-protein kinase B and mitogen-activated protein kinase pathways. Hence, Tregs might serve as a promising therapeutic approach for DCM treatment.

Sodium-dependent glucose transporter 2 inhibitors effects on myocardial function in patients with type 2 diabetes and asymptomatic heart failure

BACKGROUND

Sodium-dependent glucose transporter 2 inhibitors (SGLT2i) have shown efficacy in reducing heart failure (HF) burden in a very heterogeneous groups of patients, raising doubts about some contemporary assumptions of their mechanism of action. We previously published a prospective observational study that evaluated mechanisms of action of SGLT2i in patients with type 2 diabetes who were in HF stages A and B on dual hypoglycemic therapy. Two groups of patients were included in the study: the ones receiving SGLT2i as an add-on agent to metformin and the others on dipeptidyl peptidase-4 inhibitors as an add-on to metformin due to suboptimal glycemic control.

AIM

To evaluate the outcomes regarding natriuretic peptide, oxidative stress, inflammation, blood pressure, heart rate, cardiac function, and body weight.

METHODS

The study outcomes were examined by dividing each treatment arm into two subgroups according to baseline parameters of global longitudinal strain (GLS), N-terminal pro-brain natriuretic peptide, myeloperoxidase (MPO), high-sensitivity C-reactive protein (hsCRP), and systolic and diastolic blood pressure. To evaluate the possible predictors of observed changes in the SGLT2i arm during follow-up, a rise in stroke volume index, body mass index (BMI) decrease, and lack of heart rate increase, linear regression analysis was performed.

RESULTS

There was a greater reduction of MPO, hsCRP, GLS, and blood pressure in the groups with higher baseline values of mentioned parameters irrespective of the therapeutic arm after 6 months of follow-up. Significant independent predictors of heart rate decrease were a reduction in early mitral inflow velocity to early diastolic mitral annular velocity at the interventricular septal annulus ratio and BMI, while the predictor of stroke volume index increase was SGLT2i therapy itself.

CONCLUSION

SGLT2i affect body composition, reduce cardiac load, improve diastolic/systolic function, and attenuate the sympathetic response. Glycemic control contributes to the improvement of heart function, blood pressure control, oxidative stress, and reduction in inflammation.

Methanolic Extract of Phoenix Dactylifera Confers Protection against Experimental Diabetic Cardiomyopathy through Modulation of Glucolipid Metabolism and Cardiac Remodeling

The incidence of cardiovascular disorders is continuously rising, and there are no effective drugs to treat diabetes-associated heart failure. Thus, there is an urgent need to explore alternate approaches, including natural plant extracts, which have been successfully exploited for therapeutic purposes. The current study aimed to explore the cardioprotective potential of Phoenix dactylifera (PD) extract in experimental diabetic cardiomyopathy (DCM). Following in vitro phytochemical analyses, Wistar albino rats (N = 16, male; age 2-3 weeks) were fed with a high-fat or standard diet prior to injection of streptozotocin (35 mg/kg i.p.) after 2 months and separation into the following four treatment groups: healthy control, DCM control, DCM metformin (200 mg/kg/day, as the reference control), and DCM PD treatment (5 mg/kg/day). After 25 days, glucolipid and myocardial blood and serum markers were assessed along with histopathology and gene expression of both heart and pancreatic tissues. The PD treatment improved glucolipid balance (FBG 110 ± 5.5 mg/dL; insulin 17 ± 3.4 ng/mL; total cholesterol 75 ± 8.5 mg/dL) and oxidative stress (TOS 50 ± 7.8 H2O2equiv./L) in the DCM rats, which was associated with preserved structural integrity of both the pancreas and heart compared to the DCM control (FBG 301 ± 10 mg/dL; insulin 27 ± 3.4 ng/mL; total cholesterol 126 ± 10 mg/dL; TOS 165 ± 12 H2O2equiv./L). Gene expression analyses revealed that PD treatment upregulated the expression of insulin signaling genes in pancreatic tissue (INS-I 1.69 ± 0.02; INS-II 1.3 ± 0.02) and downregulated profibrotic gene expression in ventricular tissue (TGF-β 1.49 ± 0.04) compared to the DCM control (INS-I 0.6 ± 0.02; INS-II 0.49 ± 0.03; TGF-β 5.7 ± 0.34). Taken together, these data indicate that Phoenix dactylifera may offer cardioprotection in DCM by regulating glucolipid balance and metabolic signaling.

Methionine sulfoxide reductase B2 protects against cardiac complications in diabetes mellitus

Diabetes mellitus (DM) is a progressive, chronic metabolic disorder characterized by high oxidative stress, which can lead to cardiac damage. Methionine sulfoxylation (MetO) of proteins by excessive reactive oxygen species (ROS) can impair the basic functionality of essential cellular proteins, contributing to heart failure. Methionine sulfoxide reductase B2 (MsrB2) can reverse oxidation induced MetO in mitochondrial proteins, so we investigated its role in diabetic cardiomyopathy. We observed that DM-induced heart damage in diabetic mice model is characterized by increased ROS, increased protein MetO with mitochondria structural pathology, and cardiac fibrosis. In addition, MsrB2 was significantly increased in mouse DM cardiomyocytes, supporting the induction of a protective process. Further, MsrB2 directly induces Parkin and LC3 activation (mitophagy markers) in cardiomyocytes. In MsrB2, knockout mice displayed abnormal electrophysiological function, as determined by ECG analysis. Histological analysis confirmed increased cardiac fibrosis and disrupted cardiac tissue in MsrB2 knockout DM mice. We then corroborated our findings in human DM heart samples. Our study demonstrates that increased MsrB2 expression in the heart protects against diabetic cardiomyopathy.

Polygonatum sibiricum (Huang Jing) polysaccharide reduces diabetic cardiomyopathy through increasing cyclic guanosine monophosphate-protein kinase G signaling in diabetic mice

AIMS/INTRODUCTION

Diabetic cardiomyopathy (DCM) is a prevalent condition among individuals with diabetes, and is associated with a high mortality rate. The anti-oxidant properties of Jing Huang or Polygonatum sibiricum polysaccharide (PSP) have been extensively used to treat diabetes-related disorders; however, its potential effectiveness against DCM remains unknown. This study aimed to investigate PSP's therapeutic effects on DCM in an experimental diabetic mouse model.

MATERIALS AND METHODS

To induce insulin resistance, mice were fed a high-fat diet for 3 months, followed by intraperitoneal streptozotocin injection to induce slight hyperglycemia and develop DCM. Both DCM and control mice were given PSP orally for 3 weeks. Western blotting was used to detect the protein expressions of protein kinase G, C/EBP homologous protein, glucose-regulated protein 78, phosphodiesterase type 5, protein kinase R-like endoplasmic reticulum (ER) kinase, and phospho-protein kinase R-like endoplasmic reticulum kinase in heart tissue.

RESULTS

The results showed a reduction in bodyweight and blood glucose levels in the PSP therapy group compared with DCM group. PSP also improved cardiac function and had a negligible effect on malondialdehyde activity. Furthermore, the findings showed that PSP alleviated ER and oxidative stress observed in DCM mice hearts, leading to the inhibition of cyclic guanosine monophosphate-specific phosphodiesterase type 5 and cardiac cyclic guanosine monophosphate reactivation. Phosphodiesterase type 5 inhibition reduced high-fat diet-induced cardiac dysfunction and decreased ER stress.

CONCLUSIONS

PSP could effectively protect diabetic myocardium by inhibiting endoplasmic reticulum stress. These findings provide crucial insights into the potential of PSP to ameliorate DCM conditions in diabetic mice by decreasing ER and oxidative stress, and enhancing cyclic guanosine monophosphate protein kinase G signaling.

New insights into the roles of Irisin in diabetic cardiomyopathy and vascular diseases

Diabetes mellitus (DM) is a prevalent chronic disease in the 21st century due to increased lifespan and unhealthy lifestyle choices. Extensive research indicates that exercise can play a significant role in regulating systemic metabolism by improving energy metabolism and mitigating various metabolic disorders, including DM. Irisin, a well-known exerkine, was initially reported to enhance energy expenditure by indicating the browning of white adipose tissue (WAT) through peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) signaling. In this review, we summarize the potential mechanisms underlying the beneficial effects of Irisin on glucose dysmetabolism, including reducing gluconeogenesis, enhancing insulin energy expenditure, and promoting glycogenesis. Additionally, we highlight Irisin's potential to improve diabetic vascular diseases by stimulating nitric oxide (NO) production, reducing oxidative and nitrosative stress, curbing inflammation, and attenuating endothelial cell aging. Furthermore, we discuss the potential of Irisin to improve diabetic cardiomyopathy by preventing cardiomyocyte loss and reducing myocardial hypertrophy and fibrosis. Given Irisin's promising functions in managing diabetic cardiomyopathy and vascular diseases, targeting Irisin for therapeutic purposes could be a fruitful avenue for future research and clinical interventions.

The protective effect of Macrostemonoside T from Allium macrostemon Bunge against Isoproterenol-Induced myocardial injury via the PI3K/Akt/mTOR signaling pathway

Myocardial injury (MI) signifies a pathological aspect of cardiovascular diseases (CVDs) such as coronary artery disease, diabetic cardiomyopathy, and myocarditis. Macrostemonoside T (MST) has been isolated from Allium macrostemon Bunge (AMB), a key traditional Chinese medicine (TCM) used for treating chest stuffiness and pains. Although MST has demonstrated considerable antioxidant activity in vitro, its protective effect against MI remains unexplored. To investigate MST's effects in both in vivo and in vitro models of isoproterenol (ISO)-induced MI and elucidate its underlying molecular mechanisms. This study established an ISO-induced MI model in rats and assessed H9c2 cytotoxicity to examine MST's impact on MI. Various assays, including histopathological staining, TUNEL staining, immunohistochemical staining, DCFH-DA staining, JC-1 staining, ELISA technique, and Western blot (WB), were utilized to explore the potential molecular mechanisms of MI protection. In vivo experiments demonstrated that ISO caused myocardial fiber disorders, elevated cardiac enzyme levels, and apoptosis. However, pretreatment with MST significantly mitigated these detrimental changes. In vitro experiments revealed that MST boosted antioxidant enzyme levels and suppressed malondialdehyde (MDA) production in H9c2 cells. Concurrently, MST inhibited ISO-induced reactive oxygen species (ROS) production and mitigated the decline in mitochondrial membrane potential, thereby reducing the apoptosis rate. Moreover, pretreatment with MST elevated the expression levels of p-PI3K, p-Akt, and p-mTOR, indicating activation of the PI3K/Akt/mTOR signaling pathway and consequent protection against MI. MST attenuated ISO-induced MI in rats by impeding apoptosis through activation of the PI3K/Akt/mTOR signaling pathway. This study presents potential avenues for the development of precursor drugs for CVDs.

Growth differentiation factor 11 regulates high glucose-induced cardiomyocyte pyroptosis and diabetic cardiomyopathy by inhibiting inflammasome activation

BACKGROUND

Diabetic cardiomyopathy (DCM) is a crucial complication of long-term chronic diabetes that can lead to myocardial hypertrophy, myocardial fibrosis, and heart failure. There is increasing evidence that DCM is associated with pyroptosis, a form of inflammation-related programmed cell death. Growth differentiation factor 11 (GDF11) is a member of the transforming growth factor β superfamily, which regulates oxidative stress, inflammation, and cell survival to mitigate myocardial hypertrophy, myocardial infarction, and vascular injury. However, the role of GDF11 in regulating pyroptosis in DCM remains to be elucidated. This research aims to investigate the role of GDF11 in regulating pyroptosis in DCM and the related mechanism.

METHODS AND RESULTS

Mice were injected with streptozotocin (STZ) to induce a diabetes model. H9c2 cardiomyocytes were cultured in high glucose (50 mM) to establish an in vitro model of diabetes. C57BL/6J mice were preinjected with adeno-associated virus 9 (AAV9) intravenously via the tail vein to specifically overexpress myocardial GDF11. GDF11 attenuated pyroptosis in H9c2 cardiomyocytes after high-glucose treatment. In diabetic mice, GDF11 alleviated cardiomyocyte pyroptosis, reduced myocardial fibrosis, and improved cardiac function. Mechanistically, GDF11 inhibited pyroptosis by preventing inflammasome activation. GDF11 achieved this by specifically binding to apoptosis-associated speck-like protein containing a CARD (ASC) and preventing the assembly and activation of the inflammasome. Additionally, the expression of GDF11 during pyroptosis was regulated by peroxisome proliferator-activated receptor α (PPARα).

CONCLUSION

These findings demonstrate that GDF11 can treat diabetic cardiomyopathy by alleviating pyroptosis and reveal the role of the PPARα-GDF11-ASC pathway in DCM, providing ideas for new strategies for cardioprotection.

Insulin Treatment Does Not Prevent EARLY Autonomic Cardiovascular and Diastolic Dysfunctions in Streptozotocin-Induced Diabetic Rats

Recent studies have found increased cardiovascular mortality risk in patients with type 1 diabetes when compared to normoglycemic people, even when they were kept under good glycemic control. However, the mechanisms underlying this condition have yet to be fully understood. Using streptozotocin (STZ)-induced diabetic rats, we evaluated the effects of insulin replacement therapy on cardiac, autonomic, inflammatory, and oxidative stress parameters. Daily treatment with insulin administrated subcutaneously in the STZ-diabetic rats showed a reduction in hyperglycemia (>250 mg/dL) to normalized values. The insulin treatment was effective in preventing alterations in cardiac morphometry and systolic function but had no impact on diastolic function. Also, the treatment was not able to prevent the impairment of baroreflex-tachycardic response and systolic arterial pressure variability (SAP-V). A correlation was found between improvement of these autonomic parameters and higher levels of IL-10 and lower levels of oxidized glutathione. Our findings show that insulin treatment was not able to prevent diastolic, baroreflex, and SAP-V dysfunction, suggesting an outstanding cardiovascular risk, even after obtaining a good glycemic control in STZ-induced diabetic rats. This study shed light on a relatively large population of diabetic patients in need of other therapies to be used in combination with insulin treatment and thus more effectively manage cardiovascular risk.

Potential role of resveratrol in prevention and therapy of diabetic complications: a critical review

BACKGROUND

Diabetes mellitus (DM) is a category of metabolic conditions affecting about 5% of people worldwide. High mortality associated with DM is mostly due to its severe clinical complications, including diabetic nephropathy, retinopathy, neuropathy, and cardiomyopathy. Resveratrol (RSV) is a natural, biologically active polyphenol known to have various health-promoting effects in animal models and humans.

OBJECTIVE

In this review, we have reviewed the preventive and therapeutic role of RSV on diabetes complications with emphasis on its molecular mechanisms of action.

METHODS

To prepare this review, all the basic and clinical available literatures regarding this topic were gathered through electronic databases, including PubMed, Web of Science, Scopus, and Google Scholar. Therefore, we summarized previous studies that have evaluated the effects of RSV on diabetic complications and their mechanisms. Only English language studies published up to January 2023 were included in this review.

RESULTS

RSV improves glucose homeostasis, decreases insulin resistance, induces autophagy, regulates lipid metabolism, protects pancreatic β-cells, ameliorates metabolic disorders, and increases the GLUT4 expression. These effects induced by RSV are strongly associated with ability of this polyphenol agent to elevation expression/activity of AMP-activated protein kinase and Sirtuin 1 in various organs of diabetic subjects, which leads to prevention and therapy of diabetic complications. In addition, antioxidant and anti-inflammatory properties of RSV were reported to be involved in its action in diabetic complications, such as retinopathy and nephropathy.

CONCLUSION

RSV is a promising compound for improving diabetic complications. However, the exact antidiabetic mechanisms of RSV need to be further investigated.

The potential roles of exosomes in pathological cardiomyocyte hypertrophy mechanisms and therapy: A review

Pathological cardiac hypertrophy, characterized by the enlargement of cardiac muscle cells, leads to serious cardiac conditions and stands as a major global health issue. Exosomes, comprising small lipid bilayer vesicles, are produced by various cell types and found in numerous bodily fluids. They play a pivotal role in intercellular communication by transferring bioactive cargos to recipient cells or activating signaling pathways in target cells. Exosomes from cardiomyocytes, endothelial cells, fibroblasts, and stem cells are key in regulating processes like cardiac hypertrophy, cardiomyocyte survival, apoptosis, fibrosis, and angiogenesis within the context of cardiovascular diseases. This review delves into exosomes' roles in pathological cardiac hypertrophy, first elucidating their impact on cell communication and signaling pathways. It then advances to discuss how exosomes affect key hypertrophic processes, including metabolism, fibrosis, oxidative stress, and angiogenesis. The review culminates by evaluating the potential of exosomes as biomarkers and their significance in targeted therapeutic strategies, thus emphasizing their critical role in the pathophysiology and management of cardiac hypertrophy.

Mitochondrial energy metabolism in diabetic cardiomyopathy: Physiological adaption, pathogenesis, and therapeutic targets

Diabetic cardiomyopathy is defined as abnormal structure and function of the heart in the setting of diabetes, which could eventually develop heart failure and leads to the death of the patients. Although blood glucose control and medications to heart failure show beneficial effects on this disease, there is currently no specific treatment for diabetic cardiomyopathy. Over the past few decades, the pathophysiology of diabetic cardiomyopathy has been extensively studied, and an increasing number of studies pinpoint that impaired mitochondrial energy metabolism is a key mediator as well as a therapeutic target. In this review, we summarize the latest research in the field of diabetic cardiomyopathy, focusing on mitochondrial damage and adaptation, altered energy substrates, and potential therapeutic targets. A better understanding of the mitochondrial energy metabolism in diabetic cardiomyopathy may help to gain more mechanistic insights and generate more precise mitochondria-oriented therapies to treat this disease.

Eight weeks of treatment with mineralocorticoid receptor blockade does not alter vascular function in individuals with and without type 2 diabetes

Aldosterone has been suggested to be involved in the microvascular complications observed in type 2 diabetes. We aimed to investigate the effect of mineralocorticoid receptor (MR) blockade on endothelial function in individuals with type 2 diabetes compared to healthy controls. We included 12 participants with type 2 diabetes and 14 controls. We measured leg hemodynamics at baseline and during femoral arterial infusion of acetylcholine and sodium nitroprusside before and 8 weeks into treatment with MR blockade (eplerenone). Acetylcholine infusion was repeated with concomitant n-acetylcysteine (antioxidant) infusion. No difference in leg blood flow or vascular conductance was detected before or after the treatment with MR blockade in both groups and there was no difference between groups. Infusion of n-acetylcysteine increased baseline blood flow and vascular conductance, but did not change the vascular response to acetylcholine before or after treatment with MR blockade. Skeletal muscle eNOS content was unaltered by MR blockade and no difference between groups was detected. In conclusion, we found no effect of MR blockade endothelial function in individuals with and without type 2 diabetes. As the individuals with type 2 diabetes did not have vascular dysfunction, these results might not apply to individuals with vascular dysfunction.

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.

Chronic intermittent hypoxia aggravated diabetic cardiomyopathy through LKB1/AMPK/Nrf2 signaling pathway

Chronic intermittent hypoxia (CIH) may play an important role in the development of diabetic cardiomyopathy (DCM). However, the exact mechanism of CIH-induced myocardial injury in DCM remains unclear. In vivo, the db/db mice exposed to CIH were established, and in vitro, the H9C2 cells were exposed to high glucose (HG) combined with intermittent hypoxia (IH). The body weight (BW), fasting blood glucose (FBG) and food intake were measured every two weeks. The glycolipid metabolism was assessed with the oral glucose tolerance test (OGTT) and insulin resistance (IR). Cardiac function was detected by echocardiography. Cardiac pathology was detected by HE staining, Masson staining, and transmission electron microscopy. The level of reactive oxygen species (ROS) in myocardial tissue was detected by dihydroethidium (DHE). The apoptosis was detected by TUNEL staining. The cell viability, ROS, and the mitochondrial membrane potential were detected by the cell counting kit-8 (CCK-8) assay and related kits. Western blotting was used to analyze the liver kinase B1/AMP-activated protein kinase/ nuclear factor-erythroid 2-related factor 2 (LKB1/AMPK/Nrf2) signaling pathway. CIH exposure accelerated glycolipid metabolism disorders and cardiac injury, and increased the level of cardiac oxidative stress and the number of positive apoptotic cells in db/db mice. IH and HG decreased the cell viability and the level of mitochondrial membrane potential, and increased ROS expression in H9C2 cells. These findings indicate that CIH exposure promotes glycolipid metabolism disorders and myocardial apoptosis, aggravating myocardial injury via the LKB1/AMPK/Nrf2 pathway in vitro and in vivo.

Early detection of myocardial involvement by non-contrast T1ρ mapping of cardiac magnetic resonance in type 2 diabetes mellitus

Objective

This study aims to determine the effectiveness of T1ρ in detecting myocardial fibrosis in type 2 diabetes mellitus (T2DM) patients by comparing with native T1 and extracellular volume (ECV) fraction.

Methods

T2DM patients (n = 35) and healthy controls (n = 30) underwent cardiac magnetic resonance. ECV, T1ρ, native T1, and global longitudinal strain (GLS) values were assessed. Diagnostic performance was analyzed using receiver operating curves.

Results

The global ECV and T1ρ of T2DM group (ECV = 32.1 ± 3.2%, T1ρ = 51.6 ± 3.8 msec) were significantly higher than those of controls (ECV = 26.2 ± 1.6%, T1ρ = 46.8 ± 2.0 msec) (all P < 0.001), whether there was no significant difference in native T1 between T2DM and controls (P = 0.264). The GLS decreased significantly in T2DM patients compared with controls (-16.5 ± 2.4% vs. -18.3 ± 2.6%, P = 0.015). The T1ρ and native T1 were associated with ECV (Pearson's r = 0.50 and 0.25, respectively, both P < 0.001); the native T1, T1ρ, and ECV were associated with hemoglobin A1c (Pearson's r = 0.41, 0.52, and 0.61, respectively, all P < 0.05); and the ECV was associated with diabetes duration (Pearson's r = 0.41, P = 0.016). The AUC of ECV, T1ρ, GLS, and native T1 were 0.869, 0.810, 0.659, and 0.524, respectively.

Conclusion

In T2DM patients, T1ρ may be a new non-contrast cardiac magnetic resonance technique for identifying myocardial diffuse fibrosis, and T1ρ may be more sensitive than native T1 in the detection of myocardial diffuse fibrosis.

Ubiquitin-conjugating enzyme E2 for regulating autophagy in diabetic cardiomyopathy: A mini-review

The prevalence of diabetic cardiomyopathy (DCM) increases year by year with the increase in the prevalence of diabetes mellitus (DM), which is one of the most serious cardiovascular complications of DM and a major cause of death in diabetic patients. Although the pathological molecular features of DCM have not been fully elucidated, increasing evidence suggests that impaired autophagy in cardiomyocytes plays a nonnegligible role in the development of DCM. It has been shown that SUMOylation [SUMO = small ubiquitin-like modifier], a post-translational modification of proteins, and its associated ubiquitin-proteasome system mediates protein quality control in the heart and plays an important role in the proteotoxic environment of the heart. Specifically, the expression of ubiquitin-conjugating enzyme E2 (Ubc9), the only SUMO-E2 enzyme, exerts a positive regulatory effect on autophagy in cardiomyocytes with potential cardioprotective effects. This review focuses on the role that autophagy plays in DCM and the potential for Ubc9-regulated autophagy pathways to ameliorate DCM, highlighting the potential of Ubc9 as an interventional target in DCM and providing new insights into the pathogenesis of the disease.

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

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Interplay Between TGF-β Signaling and MicroRNA in Diabetic Cardiomyopathy

In diabetic patients, concomitant cardiovascular disease is the main factor contributing to their morbidity and mortality. Diabetic cardiomyopathy (DCM) is a form of cardiovascular disease associated with diabetes that can result in heart failure. Transforming growth factor-β (TGF-β) isoforms play a crucial role in heart remodeling and repair and are elevated and activated in myocardial disorders. Alterations in certain microRNAs (miRNA) are closely related to diabetic cardiomyopathy. One or more miRNA molecules target the majority of TGF-β pathway components, and TGF-β directly or via SMADs controls miRNA synthesis. Based on these interactions, this review discusses potential cross-talk between TGF-β signaling and miRNA in DCM in order to investigate the creation of potential therapeutic targets.

N-acetylcysteine combined with insulin attenuates myocardial injury in canines with type 1 diabetes mellitus by modulating TNF-α-mediated apoptotic pathways and affecting linear ubiquitination

The exact pathogenesis of type 1 diabetes mellitus (DM) is still unclear. Numerous organs, including the heart, will suffer damage and malfunction as a result of long-term hyperglycemia. Currently, insulin therapy alone is still not the best treatment for type 1 DM. In order to properly treat and manage patients with type 1 DM, it is vital to seek a combination that includes both insulin and additional medications. This study aims to explore the therapeutic effect and mechanism of N-acetylcysteine (NAC) combined with insulin on type 1 DM. By giving beagle canines injections of streptozotocin (STZ) and alloxan (ALX) (20 mg/kg each), a model of type 1 DM was created. The results showed that this combination could effectively control blood sugar level, improve heart function, avoid the damage of mitochondria and myocardial cells, and prevent the excessive apoptosis of myocardial cells. Importantly, the combination can activate nuclear factor kappa-B (NF-κB) by promoting linear ubiquitination of receptor-interacting protein kinase 1 (RIPK1) and NF-κB-essential modulator (NEMO) and inhibitor of NF-κB (IκB) phosphorylation. The combination can increase the transcription and linear ubiquitination of Cellular FLICE (FADD-like IL-1β-converting enzyme) -inhibitory protein (c-FLIP), diminish the production of cleaved-caspase-8 p18 and cleaved-caspase-3 to reduce apoptosis. This study confirmed that NAC combined with insulin can promote the linear ubiquitination of RIPK1, NEMO and c-FLIP and regulate the apoptosis pathway mediated by TNF-α to attenuate the myocardial injury caused by type 1 DM. Meanwhile, the research served as a resource when choosing a clinical strategy for DM cardiac complications.

Targeting mitochondrial quality control for diabetic cardiomyopathy: Therapeutic potential of hypoglycemic drugs

Diabetic cardiomyopathy is a chronic cardiovascular complication caused by diabetes that is characterized by changes in myocardial structure and function, ultimately leading to heart failure and even death. Mitochondria serve as the provider of energy to cardiomyocytes, and mitochondrial dysfunction plays a central role in the development of diabetic cardiomyopathy. In response to a series of pathological changes caused by mitochondrial dysfunction, the mitochondrial quality control system is activated. The mitochondrial quality control system (including mitochondrial biogenesis, fusion and fission, and mitophagy) is core to maintaining the normal structure of mitochondria and performing their normal physiological functions. However, mitochondrial quality control is abnormal in diabetic cardiomyopathy, resulting in insufficient mitochondrial fusion and excessive fission within the cardiomyocyte, and fragmented mitochondria are not phagocytosed in a timely manner, accumulating within the cardiomyocyte resulting in cardiomyocyte injury. Currently, there is no specific therapy or prevention for diabetic cardiomyopathy, and glycemic control remains the mainstay. In this review, we first elucidate the pathogenesis of diabetic cardiomyopathy and explore the link between pathological mitochondrial quality control and the development of diabetic cardiomyopathy. Then, we summarize how clinically used hypoglycemic agents (including sodium-glucose cotransport protein 2 inhibitions, glucagon-like peptide-1 receptor agonists, dipeptidyl peptidase-4 inhibitors, thiazolidinediones, metformin, and α-glucosidase inhibitors) exert cardioprotective effects to treat and prevent diabetic cardiomyopathy by targeting the mitochondrial quality control system. In addition, the mechanisms of complementary alternative therapies, such as active ingredients of traditional Chinese medicine, exercise, and lifestyle, targeting mitochondrial quality control for the treatment of diabetic cardiomyopathy are also added, which lays the foundation for the excavation of new diabetic cardioprotective drugs.

Transient receptor potential vanilloid type 1: cardioprotective effects in diabetic models

Cardiovascular disease, especially heart failure (HF) is the leading cause of death in patients with diabetes. Individuals with diabetes are prone to a special type of cardiomyopathy called diabetic cardiomyopathy (DCM), which cannot be explained by heart diseases such as hypertension or coronary artery disease, and can contribute to HF. Unfortunately, the current treatment strategy for diabetes-related cardiovascular complications is mainly to control blood glucose levels; nonetheless, the improvement of cardiac structure and function is not ideal. The transient receptor potential cation channel subfamily V member 1 (TRPV1), a nonselective cation channel, has been shown to be universally expressed in the cardiovascular system. Increasing evidence has shown that the activation of TRPV1 channel has a potential protective influence on the cardiovascular system. Numerous studies show that activating TRPV1 channels can improve the occurrence and progression of diabetes-related complications, including cardiomyopathy; however, the specific mechanisms and effects are unclear. In this review, we summarize that TRPV1 channel activation plays a protective role in the heart of diabetic models from oxidation/nitrification stress, mitochondrial function, endothelial function, inflammation, and cardiac energy metabolism to inhibit the occurrence and progression of DCM. Therefore, TRPV1 may become a latent target for the prevention and treatment of diabetes-induced cardiovascular complications.

Mapping the cellular and molecular landscape of cardiac non-myocytes in murine diabetic cardiomyopathy

Diabetes is associated with a significantly elevated risk of heart failure. However, despite extensive efforts to characterize the phenotype of the diabetic heart, the molecular and cellular protagonists that underpin cardiac pathological remodeling in diabetes remain unclear, with a notable paucity of data regarding the impact of diabetes on non-myocytes within the heart. Here we aimed to define key differences in cardiac non-myocytes between spontaneously type-2 diabetic (db/db) and healthy control (db/h) mouse hearts. Single-cell transcriptomic analysis revealed a concerted diabetes-induced cellular response contributing to cardiac remodeling. These included cell-specific activation of gene programs relating to fibroblast hyperplasia and cell migration, and dysregulation of pathways involving vascular homeostasis and protein folding. This work offers a new perspective for understanding the cellular mediators of diabetes-induced cardiac pathology, and pathways that may be targeted to address the cardiac complications associated with diabetes.

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.

Protective effects of catalpol on cardio-cerebrovascular diseases: A comprehensive review

Catalpol, an iridoid glucoside isolated from Rehmannia glutinosa, has gained attention due to its potential use in treating cardio-cerebrovascular diseases (CVDs). This extensive review delves into recent studies on catalpol's protective properties in relation to various CVDs, such as atherosclerosis, myocardial ischemia, infarction, cardiac hypertrophy, and heart failure. The review also explores the compound's anti-oxidant, anti-inflammatory, and anti-apoptotic characteristics, emphasizing the role of vital signaling pathways, including PGC-1α/TERT, PI3K/Akt, AMPK, Nrf2/HO-1, estrogen receptor (ER), Nox4/NF-κB, and GRP78/PERK. The article discusses emerging findings on catalpol's ability to alleviate diabetic cardiovascular complications, thrombosis, and other cardiovascular-related conditions. Although clinical studies specifically addressing catalpol's impact on CVDs are scarce, the compound's established safety and well-tolerated nature suggest that it could be a valuable treatment alternative for CVD patients. Further investigation into catalpol and related iridoid derivatives may unveil new opportunities for devising natural and efficacious CVD therapies.