Teneligliptin mitigates diabetic cardiomyopathy by inhibiting activation of the NLRP3 inflammasome

BACKGROUND Diabetic cardiomyopathy(DCM),which is a complication of diabetes,poses a great threat to public health.Recent studies have confirmed the role of NLRP3(NOD-like receptor protein 3)activation in DCM development through the inflammatory response.Teneligliptin is an oral hypoglycemic dipeptidyl peptidase-IV inhibitor used to treat diabetes.Teneligliptin has recently been reported to have anti-inflammatory and protective effects on myocardial cells.AIM To examine the therapeutic effects of teneligliptin on DCM in diabetic mice.METHODS Streptozotocin was administered to induce diabetes in mice,followed by treatment with 30 mg/kg teneligliptin.RESULTS Marked increases in cardiomyocyte area and cardiac hypertrophy indicator heart weight/tibia length reductions in fractional shortening,ejection fraction,and heart rate;increases in creatine kinase-MB(CK-MB),aspartate transaminase(AST),and lactate dehydrogenase(LDH)levels;and upregulated NADPH oxidase 4 were observed in diabetic mice,all of which were significantly reversed by teneligliptin.Moreover,NLRP3 inflammasome activation and increased release of interleukin-1βin diabetic mice were inhibited by teneligliptin.Primary mouse cardiomyocytes were treated with high glucose(30 mmol/L)with or without teneligliptin(2.5 or 5μM)for 24 h.NLRP3 inflammasome activation.Increases in CKMB,AST,and LDH levels in glucose-stimulated cardiomyocytes were markedly inhibited by teneligliptin,and AMP(p-adenosine 5‘-monophosphate)-p-AMPK(activated protein kinase)levels were increased.Furthermore,the beneficial effects of teneligliptin on hyperglycaemia-induced cardiomyocytes were abolished by the AMPK signaling inhibitor compound C.CONCLUSION Overall,teneligliptin mitigated DCM by mitigating activation of the NLRP3 inflammasome.

Jianpi Qinghua Formula Alleviates Diabetic Myocardial Injury Through Inhibiting JunB/c-Fos Expression

Objective Diabetic cardiomyopathy(DCM)represents a substantial risk factor for heart failure and increased mortality in individuals afflicted with diabetes mellitus(DM).DCM typically manifests as myocardial fibrosis,myocardial hypertrophy,and impaired left ventricular diastolic function.While the clinical utility of the Jianpi Qinghua(JPQH)formula has been established in treating diabetes and insulin resistance,its potential efficacy in alleviating diabetic cardiomyopathy remains uncertain.This study aims to investigate the impact and underlying molecular mechanisms of the JPQH formula(JPQHF)in ameliorating myocardial injury in nonobese diabetic rats,specifically focusing on apoptosis and inflammation.Methods Wistar rats were assigned as the normal control group(CON),while Goto-Kakizaki(GK)rats were randomly divided into three groups:DM,DM treated with the JPQHF,and DM treated with metformin(MET).Following a 4-week treatment regimen,various biochemical markers related to glucose metabolism,cardiac function,cardiac morphology,and myocardial ultrastructure in GK rats were assessed.RNA sequencing was utilized to analyze differential gene expression and identify potential therapeutic targets.In vitro experiments involved high glucose to induce apoptosis and inflammation in H9c2 cells.Cell viability was evaluated using CCK-8 assay,apoptosis was monitored via flow cytometry,and the production of inflammatory cytokines was measured using quantitative real-time PCR(qPCR)and ELISA.Protein expression levels were determined by Western blotting analysis.The investigation also incorporated the use of MAPK inhibitors to further elucidate the mechanism at both the transcriptional and protein levels.Results The JPQHF group exhibited significant reductions in interventricular septal thickness at end-systole(IVSs)and left ventricular internal diameter at end-systole and end-diastole(LVIDs and LVIDd).JPQHF effectively suppressed high glucose-induced activation of IL-1βand caspase 3 in cardiomyocytes.Furthermore,JPQHF downregulated the expression of myocardial JunB/c-Fos,which was upregulated in both diabetic rats and high glucose-treated H9c2 cells.Conclusion The JPQH formula holds promise in mitigating diabetic myocardial apoptosis and inflammation in cardiomyocytes by inhibiting JunB/c-Fos expression through suppressing the MAPK(p38 and ERK1/2)pathway.

Identification of immune feature genes and intercellular profiles in diabetic cardiomyopathy

BACKGROUND Diabetic cardiomyopathy(DCM)is a multifaceted cardiovascular disorder in which immune dysregulation plays a pivotal role.The immunological molecular mechanisms underlying DCM are poorly understood.AIM To examine the immunological molecular mechanisms of DCM and construct diagnostic and prognostic models of DCM based on immune feature genes(IFGs).METHODS Weighted gene co-expression network analysis along with machine learning methods were employed to pinpoint IFGs within bulk RNA sequencing(RNA-seq)datasets.Single-sample gene set enrichment analysis(ssGSEA)facilitated the analysis of immune cell infiltration.Diagnostic and prognostic models for these IFGs were developed and assessed in a validation cohort.Gene expression in the DCM cell model was confirmed through real time-quantitative polymerase chain reaction and western blotting techniques.Additionally,single-cell RNA-seq data provided deeper insights into cellular profiles and interactions.RESULTS The overlap between 69 differentially expressed genes in the DCM-associated module and 2483 immune genes yielded 7 differentially expressed immune-related genes.Four IFGs showed good diagnostic and prognostic values in the validation cohort:Proenkephalin(Penk)and retinol binding protein 7(Rbp7),which were highly expressed,and glucagon receptor and inhibin subunit alpha,which were expressed at low levels in DCM patients(all area under the curves>0.9).SsGSEA revealed that IFG-related immune cell infiltration primarily involved type 2 T helper cells.High expression of Penk(P<0.0001)and Rbp7(P=0.001)was detected in cardiomyocytes and interstitial cells and further confirmed in a DCM cell model in vitro.Intercellular events and communication analysis revealed abnormal cellular phenotype transformation and signaling communication in DCM,especially between mesenchymal cells and macrophages.CONCLUSION The present study identified Penk and Rbp7 as potential DCM biomarkers,and aberrant mesenchymal-immune cell phenotype communication may be an important aspect of DCM pathogenesis.

Diabetic cardiomyopathy:Emerging therapeutic options

Diabetic cardiomyopathy(DbCM)is a common but underrecognized complication of patients with diabetes mellitus(DM).Although the pathobiology of other cardiac complications of diabetes such as ischemic heart disease and cardiac autonomic neuropathy are mostly known with reasonable therapeutic options,the mechanisms and management options for DbCM are still not fully understood.In its early stages,DbCM presents with diastolic dysfunction followed by heart failure(HF)with preserved ejection fraction that can progress to systolic dysfunction and HF with reduced ejection fraction in its advanced stages unless appropriately managed.Apart from prompt control of DM with lifestyle changes and antidiabetic medications,disease-modifying therapy for DbCM includes prompt control of hypertension and dyslipidemia inherent to patients with DM as in other forms of heart diseases and the use of treatments with proven efficacy in HF.A basic study by Zhang et al,in a recent issue of the World Journal of Diabetes elaborates the potential pathophysiological alterations and the therapeutic role of teneligliptin in diabetic mouse models with DbCM.Although this preliminary basic study might help to improve our understanding of DbCM and offer a potential new management option for patients with the disease,the positive results from such animal models might not always translate to clinical practice as the pathobiology of DbCM in humans could be different.However,such experimental studies can encourage more scientific efforts to find a better solution to treat patients with this enigmatic disease.

Potential mechanism of teneligliptin in the treatment of diabetic cardiomyopathy

Diabetic cardiomyopathy(DCM),a complication of diabetes,poses a significant threat to public health,both its diagnosis and treatment presents challenges.Teneligliptin has promising applications and research implications in the treat-ment of diabetes mellitus.Zhang et al observed the therapeutic effect of tenelig-liptin on cardiac function in mice with DCM.They validated that teneligliptin’s mechanism of action in treating DCM involves cardiomyocyte protection and inhibition of NLRP3 inflammasome activity.Given that the NLRP3 inflammasome plays a crucial role in the onset and progression of DCM,it presents a promising therapeutic target.Nevertheless,further clinical validation is required to ascertain the preventive and therapeutic efficacy of teneligliptin in DCM.

Macrophage modulation with dipeptidyl peptidase-4 inhibitors:A new frontier for treating diabetic cardiomyopathy?

This editorial introduces the potential of targeting macrophage function for diabetic cardiomyopathy(DCM)treatment by dipeptidyl peptidase-4(DPP-4)inhibitors.Zhang et al studied teneligliptin,a DPP-4 inhibitor used for diabetes management,and its potential cardioprotective effects in a diabetic mouse model.They suggested teneligliptin administration may reverse established markers of DCM,including cardiac hypertrophy and compromised function.It also inhibited the NLRP3 inflammasome and reduced inflammatory cytokine production in diabetic mice.Macrophages play crucial roles in DCM pathogenesis.Chronic hyperglycemia disturbs the balance between pro-inflammatory(M1)and antiinflammatory(M2)macrophages,favoring a pro-inflammatory state contributing to heart damage.Here,we highlight the potential of DPP-4 inhibitors to modulate macrophage function and promote an anti-inflammatory environment.These compounds may achieve this by elevating glucagon-like peptide-1 levels and potentially inhibiting the NLRP3 inflammasome.Further studies on teneligliptin in combination with other therapies targeting different aspects of DCM could be suggested for developing more effective treatment strategies to improve cardiovascular health in diabetic patients.

Atorvastatin ameliorated myocardial fibrosis by inhibiting oxidative stress and modulating macrophage polarization in diabetic cardiomyopathy

In this editorial,we commented on the article published in the recent issue of the World Journal of Diabetes.Diabetic cardiomyopathy(DCM)is characterized by myocardial fibrosis,ventricular hypertrophy and diastolic dysfunction in diabetic patients,which can cause heart failure and threaten the life of patients.The pathogenesis of DCM has not been fully clarified,and it may involve oxidative stress,inflammatory stimulation,apoptosis,and autophagy.There is lack of effective therapies for DCM in the clinical practice.Statins have been widely used in the clinical practice for years mainly to reduce cholesterol and stabilize arterial plaques,and exhibit definite cardiovascular protective effects.Studies have shown that statins also have anti-inflammatory and antioxidant effects.We were particularly concerned about the recent findings that atorvastatin alleviated myocardial fibrosis in db/db mice by regulating the antioxidant stress and antiinflammatory effects of macrophage polarization on diabetic myocardium,and thereby improving DCM.

Diabetic cardiomyopathy:Importance of direct evidence to support the roles of NOD-like receptor protein 3 inflammasome and pyroptosis

Recently,the roles of pyroptosis,a form of cell death induced by activated NODlike receptor protein 3(NLRP3)inflammasome,in the pathogenesis of diabetic cardiomyopathy(DCM)have been extensively investigated.However,most studies have focused mainly on whether diabetes increases the NLRP3 inflammasome and associated pyroptosis in the heart of type 1 or type 2 diabetic rodent models,and whether various medications and natural products prevent the development of DCM,associated with decreased levels of cardiac NLRP3 inflammasome and pyroptosis.The direct link of NLRP3 inflammasome and associated pyroptosis to the pathogenesis of DCM remains unclear based on the limited evidence derived from the available studies,with the approaches of NLRP3 gene silencing or pharmaceutical application of NLRP3 specific inhibitors.We thus emphasize the requirement for more systematic studies that are designed to provide direct evidence to support the link,given that several studies have provided both direct and indirect evidence under specific conditions.This editorial emphasizes that the current investigation should be circumspect in its conclusion,i.e.,not overemphasizing its role in the pathogenesis of DCM with the fact of only significantly increased expression or activation of NLRP3 inflammasome and pyroptosis in the heart of diabetic rodent models.Only clear-cut evidence-based causative roles of NLRP3 inflammasome and pyroptosis in the pathogenesis of DCM can help to develop effective and safe medications for the clinical management of DCM,targeting these biomarkers.

Empagliflozin ameliorates diabetic cardiomyopathy probably via activating AMPK/PGC-1αand inhibiting the RhoA/ROCK pathway

BACKGROUND Diabetic cardiomyopathy(DCM)increases the risk of hospitalization for heart failure(HF)and mortality in patients with diabetes mellitus.However,no specific therapy to delay the progression of DCM has been identified.Mitochondrial dysfunction,oxidative stress,inflammation,and calcium handling imbalance play a crucial role in the pathological processes of DCM,ultimately leading to cardiomyocyte apoptosis and cardiac dysfunctions.Empagliflozin,a novel glucoselowering agent,has been confirmed to reduce the risk of hospitalization for HF in diabetic patients.Nevertheless,the molecular mechanisms by which this agent provides cardioprotection remain unclear.AIM To investigate the effects of empagliflozin on high glucose(HG)-induced oxidative stress and cardiomyocyte apoptosis and the underlying molecular mechanism.METHODS Twelve-week-old db/db mice and primary cardiomyocytes from neonatal rats stimulated with HG(30 mmol/L)were separately employed as in vivo and in vitro models.Echocardiography was used to evaluate cardiac function.Flow cytometry and TdT-mediated dUTP-biotin nick end labeling staining were used to assess apoptosis in myocardial cells.Mitochondrial function was assessed by cellular ATP levels and changes in mitochondrial membrane potential.Furthermore,intracellular reactive oxygen species production and superoxide dismutase activity were analyzed.Real-time quantitative PCR was used to analyze Bax and Bcl-2 mRNA expression.Western blot analysis was used to measure the phosphorylation of AMP-activated protein kinase(AMPK)and myosin phosphatase target subunit 1(MYPT1),as well as the peroxisome proliferator-activated receptor-γcoactivator-1α(PGC-1α)and active caspase-3 protein levels.RESULTSIn the in vivo experiment, db/db mice developed DCM. However, the treatment of db/db mice with empagliflozin(10 mg/kg/d) for 8 wk substantially enhanced cardiac function and significantly reduced myocardial apoptosis,accompanied by an increase in the phosphorylation of AMPK and PGC-1α protein levels, as well as a decrease inthe phosphorylation of MYPT1 in the heart. In the in vitro experiment, the findings indicate that treatment ofcardiomyocytes with empagliflozin (10 μM) or fasudil (FA) (a ROCK inhibitor, 100 μM) or overexpression of PGC-1α significantly attenuated HG-induced mitochondrial injury, oxidative stress, and cardiomyocyte apoptosis.However, the above effects were partly reversed by the addition of compound C (CC). In cells exposed to HG,empagliflozin treatment increased the protein levels of p-AMPK and PGC-1α protein while decreasing phosphorylatedMYPT1 levels, and these changes were mitigated by the addition of CC. Adding FA and overexpressingPGC-1α in cells exposed to HG substantially increased PGC-1α protein levels. In addition, no sodium-glucosecotransporter (SGLT)2 protein expression was detected in cardiomyocytes.CONCLUSION Empagliflozin partially achieves anti-oxidative stress and anti-apoptotic effects on cardiomyocytes under HGconditions by activating AMPK/PGC-1α and suppressing of the RhoA/ROCK pathway independent of SGLT2.

Hyperglycemia-induced myocardial fibrosis may be associated with pyroptosis and apoptosis of cardiomyoctes in diabetic mice

Myocardial fibrosis is an important manifestation of diabetic cardiomyopathy.This study investigated the potential mechanism of diabetic myocardial fibrosis.Male C57BL/6J and db/db mice aged 8 weeks were randomly divided into the diabetic(DB)and control groups.At 20 weeks,the mouse heart was harvested and subjected to hematoxylin-eosin staining(HE)and Masson staining to investigate the degree of fibrosis.The expressions of transforming growth factor-beta 1(TGF-β1),collagen-III,B-cell lymphoma-2(Bcl2),Bcl2-associated X protein(Bax),cleaved gasdermin D(GSDMD),cysteinyl aspartate specific proteinase-1(caspase-1),apoptosis-associated speck-like protein containing a CARD(ASC),and nucleotide-binding oligomerization domain(NOD)-like receptor 3(NLRP3)were measured by western blotting.Immunohistochemistry and TdT-mediated dUTP nick end labeling(TUNEL)staining were performed to analyze the development of apoptosis and pyroptosis.A significant increase in body weight and blood glucose in the DB group was observed.Myocardial pathological injury,fibrosis,apoptosis,and pyroptosis were more obvious and serious in the DB group.The expression of anti-apoptotic Bcl2 significantly decreased,while the expression levels of pro-apoptotic Bax,caspase-3,and pyroptosis-related proteins,such as cleaved GSDMD,and caspase-1 in the DB group were significantly increased.Pyroptosis and apoptosis were probably the main mechanisms that caused myocardial fibrosis in mice with diabetes.

Integrated mass spectrometry imaging reveals spatial-metabolic alteration in diabetic cardiomyopathy and the intervention effects of ferulic acid

Diabetic cardiomyopathy(DCM)is a metabolic disease and a leading cause of heart failure among people with diabetes.Mass spectrometry imaging(MSI)is a versatile technique capable of combining the molecular specificity of mass spectrometry(MS)with the spatial information of imaging.In this study,we used MSI to visualize metabolites in the rat heart with high spatial resolution and sensitivity.We optimized the air flow-assisted desorption electrospray ionization(AFADESI)-MSI platform to detect a wide range of metabolites,and then used matrix-assisted laser desorption ionization(MALDI)-MSI for increasing metabolic coverage and improving localization resolution.AFADESI-MSI detected 214 and 149 metabolites in positive and negative analyses of rat heart sections,respectively,while MALDI-MSI detected 61 metabolites in negative analysis.Our study revealed the heterogenous metabolic profile of the heart in a DCM model,with over 105 region-specific changes in the levels of a wide range of metabolite classes,including carbohydrates,amino acids,nucleotides,and their derivatives,fatty acids,glycerol phospholipids,carnitines,and metal ions.The repeated oral administration of ferulic acid during 20 weeks significantly improved most of the metabolic disorders in the DCM model.Our findings provide novel insights into the molecular mechanisms underlying DCM and the potential of ferulic acid as a therapeutic agent for treating this condition.

Molecular targets and mechanisms of Jiawei Jiaotai Pill on diabetic cardiomyopathy based on network pharmacology

BACKGROUND Jiawei Jiaotai Pill is commonly used in clinical practice to reduce apoptosis,increase insulin secretion,and improve blood glucose tolerance.However,its mechanism of action in the treatment of diabetic cardiomyopathy(DCM)remains unclear,hindering research efforts aimed at developing drugs specifically for the treatment of DCM.AIM To explore the pharmacodynamic basis and molecular mechanism of Jiawei Jiaotai Pill in DCM treatment.METHODS We explored various databases and software,including the Traditional Chinese Medicine Systems Pharmacology Database,Uniport,PubChem,GenCards,String,and Cytoscape,to identify the active components and targets of Jiawei Jiaotai Pill,and the disease targets in DCM.Protein-protein interaction network,gene ontology,and Kyoto Encyclopedia of Genes and Genomes analyses were used to determine the mechanism of action of Jiawei Jiaotai Pill in treating DCM.Molecular docking of key active components and core targets was verified using AutoDock software.RESULTS Total 42 active ingredients and 142 potential targets of Jiawei Jiaotai Pill were identified.There were 100 common targets between the DCM and Jiawei Jiaotai Pills.Through this screening process,TNF,IL6,TP53,EGFR,INS,and other important targets were identified.These targets are mainly involved in the positive regulation of the mitogen-activated protein kinase(MAPK)MAPK cascade,response to xenobiotic stimuli,response to hypoxia,positive regulation of gene expression,positive regulation of cell proliferation,negative regulation of the apoptotic process,and other biological processes.It was mainly enriched in the AGE-RAGE signaling pathway in diabetic complications,DCM,PI3K-Akt,interleukin-17,and MAPK signaling pathways.Molecular docking results showed that Jiawei Jiaotai Pill's active ingredients had good docking activity with DCM's core target.CONCLUSION The active components of Jiawei Jiaotai Pill may play a role in the treatment of DCM by reducing oxidative stress,cardiomyocyte apoptosis and fibrosis,and maintaining metabolic homeostasis.

Potential therapeutic targets for the prevention of diabetic nephropathy:Glycyrrhetinic acid

Uncontrolled hyperglycemia or poorly managed disease increases the propensityfor a number of diabetes-related complications targeting major organs includingthe heart, eyes, and kidney. Although the mechanisms by which diabetes inducescardiovascular diseases include oxidative stress and inflammation, when insulinresistance remains the key to the pathogenesis, as implicated in the two reviews inthis issue. This editorial mainly comments on the potential preventive applicationof glycyrrhetinic acid (or 18β-GA) in relation to diabetic nephropathy. The therapeuticor preventive effects of 18β-GA, as a hydrolytic product of glycy-rrhizicacid that is a component of licorice, have been appreciated in other disorders, buthave received much less attention in relation to diabetic complications. A study inthis issue has identified 18β-GA as a therapeutic for preventing diabeticnephropathy and provides evidence to support efficacy in cultured human renaltubule cells in vitro. Although it represents a pilot study, the observations supporta new therapeutic approach that warrants further ex-ploration.

The protective effect and mechanism of rhein on diabetic cardiomyopathy by regulating Sirt1/PGC-1α pathway

Objective:To explore the protective effects of rhein on cardiomyocyte injury in DCM and its possible mecha-nism.Methods:The diabetic model was induced by intraperitoneal injection with streptozotocin and high-fat diet.The mice were randomly divided into control group,DM group,and DM+RH group.After 12 weeks treatment with rhein,the change of fast blood glucose,body weight,and heart weight/body weigh(t HW/BW)were observed.HE and Masson staining were used to evalu-ate myocardial structural damage.Transmission electron microscope was used to observe the myocardial mitochondrial structure.The mRNA levels of Sirt1,PGC-1α,TFAM,ANP,BNP andβ-MHC were quantified by RT-PCR.Sirt1,PGC-1α and TFAM protein levels were estimated by Western blot and IHC.Results:Compared with control group,the blood glucose,HW/BW,ANP,BNP andβ-MHC mRNA of DM group were significantly increased(P<0.05).The structures of myocardium and mitochondria were obviously destroyed in DM group.Sirt1,PGC-1α and TFAM expression were significantly decreased(P<0.05).Compared with DM group,the blood glucose,HW/BW,ANP,BNP and β-MHC mRNA of DM+RH group were decreased(P<0.05).The myocardial and mitochondrial injury were improved.Sirt1,PGC-1α and TFAM expression were significantly increased(P<0.05).Conclusion:Rhein exhibits protective effects on diabetic cardiomyopathy which may be achieved by activating Sirt1/PGC-1α pathway.

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.

Diabetic heart disease:A clinical update

Diabetes mellitus(DM) significantly increases the risk of heart disease,and DMrelated healthcare expenditure is predominantly for the management of cardiovascular complications.Diabetic heart disease is a conglomeration of coronary artery disease(CAD),cardiac autonomic neuropathy(CAN),and diabetic cardiomyopathy(DCM).The Framingham study clearly showed a 2 to 4-fold excess risk of CAD in patients with DM.Pathogenic mechanisms,clinical presentation,and management options for DM-associated CAD are somewhat different from CAD among nondiabetics.Higher prevalence at a lower age and more aggressive disease in DM-associated CAD make diabetic individuals more vulnerable to premature death.Although common among diabetic individuals,CAN and DCM are often under-recognised and undiagnosed cardiac complications.Structural and functional alterations in the myocardial innervation related to uncontrolled diabetes result in damage to cardiac autonomic nerves,causing CAN.Similarly,damage to the cardiomyocytes from complex pathophysiological processes of uncontrolled DM results in DCM,a form of cardiomyopathy diagnosed in the absence of other causes for structural heart disease.Though optimal management of DM from early stages of the disease can reduce the risk of diabetic heart disease,it is often impractical in the real world due to many reasons.Therefore,it is imperative for every clinician involved in diabetes care to have a good understanding of the pathophysiology,clinical picture,diagnostic methods,and management of diabetes-related cardiac illness,to reduce morbidity and mortality among patients.This clinical review is to empower the global scientific fraternity with up-to-date knowledge on diabetic heart disease.

Is diabetic cardiomyopathy a specific entity?

Diabetes mellitus(DM) is characterised by hyperglycemia, insulin resistance and metabolic dysregulation leading to diastolic and systolic dysfunction in diabetes. In this review, the pathogenetic and pathomorphological changes leading to diastolic and systolic dysfunction in diabetes are discussed. Changes in metabolic signalling pathways, mediators and effectors contribute to the pathogenesis of cardiac dysfunction in DM called diabetic cardiomyopathy(DC). Echocardiographic studies report on the association between DM and the presence of cardiac hypertrophy and myocardial stiffness that lead to diastolic dysfunction. More recently reported echocardiographic studies with more sensitive techniques, such as strain analysis, also observed systolic dysfunction as an early marker of DC. Depression of systolic and diastolic function is continuum and the line of separation is artificial. To conclude, according to current knowledge, DC is expected to be a common single phenotype that is caused by different pathogenetic and pathomorphological changes leading to diastolic and systolic dysfunction in diabetes.

Role of novel biomarkers in diabetic cardiomyopathy

Diabetic cardiomyopathy(DCM)is commonly defined as cardiomyopathy in patients with diabetes mellitus in the absence of coronary artery disease and hypertension.As DCM is now recognized as a cause of substantial morbidity and mortality among patients with diabetes mellitus and clinical diagnosis is still inappropriate,various expert groups struggled to identify a suitable biomarker that will help in the recognition and management of DCM,with little success so far.Hence,we thought it important to address the role of biomarkers that have shown potential in either human or animal studies and which could eventually result in mitigating the poor outcomes of DCM.Among the array of biomarkers we thoroughly analyzed,long noncoding ribonucleic acids,soluble form of suppression of tumorigenicity 2 and galectin-3 seem to be most beneficial for DCM detection,as their plasma/serum levels accurately correlate with the early stages of DCM.The combination of relatively inexpensive and accurate speckle tracking echocardiography with some of the highlighted biomarkers may be a promising screening method for newly diagnosed diabetes mellitus type 2 patients.The purpose of the screening test would be to direct affected patients to more specific confirmation tests.This perspective is in concordance with current guidelines that accentuate the importance of an interdisciplinary team-based approach.

Inhibition of NF-kB and Wnt/β-catenin/GSK3p Signaling Pathways Ameliorates Cardiomyocyte Hypertrophy and Fibrosis in Streptozotocin (STZ)-induced Type 1 Diabetic Rats

Type 1 diabetes mellitus(T1DM)is associated with an increased risk of diabetic cardiomyopathy(DCM).Nuclear factor kappa B(NF-kB)and Wnt/β-catenin/GSK3p have been demonstrated to play pathogenic roles in diabetes.In this study,we evaluated the roles of these two pathways in T1 DM-induced cardiomyopathy in rats.Streptozotocin(STZ)-induced type 1 diabetic rats were treated with pyrrolidine dithiocarbamate(PDTC)or meisoindigo(Me)to inhibit NF-kB and Wnt/β-catenin/GSK3P respectively for 4 or 8 weeks.As compared with untreated diabetic rats,treatment with either PDTC or Me partly attenuated the myocardial hypertrophy and interstitial fibrosis,improved cardiac function,and exhibited reduction in inflammatory reaction.In addition,we found that inhibiting NF-κB and Wnt/β-catenin/GSK3β pathways could regulate glucose and lipid metabolism.The effects were associated with the decrease of NF-κB activity and the downregulation of some proinflammatory cytokines,including tumor necrosis factor-alpha(TNF-α)and interleukin(IL)-2.Our data suggested that the activities of NF-κB and Wnt/β-catenin/GSK3β pathways were both increased and inhibiting NF-κB and Wnt/β-catenin/GSK3β signaling pathways might improve myocardial injury in T1DM rats.

Astragalus Prevents Diabetic Rats from Developing Cardiomyopathy by Downregulating Angiotensin Ⅱ Type2 Receptors' Expression

This study examined the potential roles of astragalus and angiotensin Ⅱ type 2 receptor (AT2) in rats with streptozotocin (STZ)-induced diabetic cardiomyopathy. Of 52 female 4-week-old Wistar rats treated with high glucose and lipid diet to induce insulin resistance, 7 treated with sodium citrate buffer (pH=4.5) served as controls (con1) and the other 45 were treated by intraperitoneal injection (ip) of STZ to induce type 2 diabetes. After 20 weeks, the maximal velocity decrease of pressure per second in left ventricle within the period of isovolumic relaxation (-dp/dt max) was detected by inserting cannula through right carotid artery. Of the 45 rats, 24 with -dp/dt max ≤700 mmHg/s (1 mmHg=0.133 kPa) developing diabetic cardiomyopathy were grouped as follows: 7 treated with double distilled H 2O (ip) were included in control group 2 (con2); other 8 treated with AT2 agonist (CGP42112A, ip) were included in experimental group1 (exp); 9 treated with astragalus (po) constituted experimental group 2 (exp2). All injections lasted 4 weeks (qd) and the heart weight (HW) was recorded. Cardiomyocyte apoptosis index (CAI), mRNA of AT2 and Bcl-2 as well as AT2 and Bcl-2 protein values in cardiomyocytes were also measured. Our results showed that -dp/dt max in exp1, exp2 and con2 were much lower than those in con1 (P<0.01 ). CAI and AT2 in both mRNA and protein in con1 were lower than those in the other three groups (P<0.01). The three parameters above were higher in exp1 but less in exp2 than those in con2, respectively (P<0.01). The three parameters and HW in exp1 were much higher than those in exp2 (P<0.01). Changes of Bcl-2 were opposite to those of AT2. Our results suggested that high expression of AT2 might accelerate the apoptosis of cardiomyocytes in diabetic rats and play an important role in precipitating diabetic cardiomyopathy and astragalus protects diabetic rats from developing cardiomyopathy by downregulating AT2.