Diabetic Cardiomyopathy Group Research Articles

Potential clinical value of fibrinogen-like protein 1 as a serum biomarker for the identification of diabetic cardiomyopathy

Diabetic individuals with diabetic cardiomyopathy (DbCM) present with abnormal myocardial structure and function. DbCM cannot be accurately diagnosed due to the lack of suitable diagnostic biomarkers. In this study, 171 eligible participants were divided into a healthy control (HC), type 2 diabetes mellitus (T2DM) patients without DbCM (T2DM), or DbCM group. Serum fibrinogen-like protein 1 (FGL-1) and other biochemical parameters were determined for all participants. Serum FGL-1 levels were significantly higher in patients with DbCM compared with those in the T2DM group and HCs. Serum FGL-1 levels were negatively correlated with left ventricular fractional shortening and left ventricular ejection fraction (LVEF) and positively correlated with left ventricular mass index in patients with DbCM after adjusting for age, sex and body mass index. Interaction of serum FGL-1 and triglyceride levels on LVEF was noted in patients with DbCM. A composite marker including serum FGL-1 and triglycerides could differentiate patients with DbCM from those with T2DM and HCs with an area under the curve of 0.773 and 0.789, respectively. Composite marker levels were negatively correlated with N-terminal B-type natriuretic peptide levels in patients with DbCM. Circulating FGL-1 may therefore be a valuable index reflecting cardiac functions in DbCM and to diagnose DbCM.

Antiapoptotic Effect of Target Protein for Xklp2 on Diabetic Rat Cardiomyocytes

This study investigates the potential of TPX2 in mitigating diabetic cardiomyopathy by modulating the Akt/FoxO1 signaling pathway. Diabetic cardiomyopathy was induced in rats using streptozotocin, and heart structure and function were assessed through echocardiography and HE staining. TPX2 expression in myocardial tissue was measured using qRT-PCR. Lentivirus was used to overexpress TPX2 specifically in myocardial tissue, followed by reassessment of cardiac structure and function. Immunohistochemical staining was employed to evaluate Caspase3 expression. In the diabetic cardiomyopathy group, rat hearts exhibited evident damage in structure and function, with increased Caspase3 expression in myocardial tissue. Conversely, TPX2 overexpression effectively improved heart structure and function while inhibiting Caspase3 upregulation. In H9C2 cells cultured with high glucose, TPX2 overexpression counteracted reduced cell activity and increased apoptosis rates. It also downregulated the mRNA levels of apoptosis-related factors (Bax, Caspase3, Caspase9) and promoted anti-apoptotic factor Bcl-2 mRNA. TPX2 overexpression inhibited Caspase3 and Caspase9 activities, upregulated Akt mRNA and protein expression, and inhibited FoxO1 mRNA and protein expression. This suggests that TPX2 may regulate the Akt/FoxO1 signaling pathway, reducing apoptosis and cardiomyocyte toxicity induced by high glucose. These findings offer potential drug targets and therapeutic strategies for diabetic cardiomyopathy treatment.

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

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. 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. 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. 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.

Empagliflozin improves mitochondrial dysfunction in diabetic cardiomyopathy by modulating ketone body metabolism and oxidative stress

Ketone bodies are considered as an alternative energy source for diabetic cardiomyopathy (DCM) and can improve the energy supply of the heart muscle, suggesting that it may be an important area of research and development as a therapeutic target for DCM. Cumulative cardiovascular trials have shown that sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce cardiovascular events in diabetic populations. Whether SGLT2 inhibitors improve DCM by enhancing ketone body metabolism remains and whether they help prevent oxidative damage remains to be clarified. Here, we present the combined results of nine GSE datasets for diabetic cardiomyopathy (GSE215979, GSE161931, GSE145294, GSE161052, GSE173384, GSE123975, GSE161827, GSE210612, and GSE5606). We found significant up-regulated gene 3-hydroxymethylglutaryl CoA synthetase 2 (HMGCS2) and down-regulated gene 3-hydroxybutyrate dehydrogenase (BDH1) and 3-oxoacid CoA-transferase1 (OXCT1), respectively. Based on the analysis of the constructed protein interaction network, it was found that HMGCS2 was in the core position of the interaction network. In addition, Gene ontology (GO) enrichment analysis mainly focused on redox process, acyl-CoA metabolic process, catalytic activity, redox enzyme activity and mitochondria. The activity of HMGCS2 in DCM heart was increased, while the expression of ketolysis enzymes BDH1 and OXCT1 was inhibited. In vivo, Empagliflozin (Emp) treated DCM group significantly decreased ventricular weight, myocardial cell cross-sectional area, and myocardial fibrosis. In addition, Emp further promoted the activity of BDH1 and OXCT1, increased the utilization of ketone bodies, further promoted the activity of HMGCS2 in DCM, and increased the synthesis of ketone bodies, prevented mitochondrial breakage and dysfunction, increased myocardial ATP to provide sufficient energy, inhibited oxidative stress and apoptosis of cardiac cells ex vivo, and improved the myocardial dysfunction of DCM. Emp can improve mitochondrial dysfunction in diabetic cardiomyopathy by regulating ketone body metabolism and oxidative stress. These findings provide a theoretical basis for evaluating Emp as a treatment for DCM.

Prevalence and clinical characteristics of diabetic cardiomyopathy in patients with acute heart failure

Background and aimsDiabetic cardiomyopathy refers to cases of diabetes mellitus (DM) complicated by cardiac dysfunction in the absence of cardiovascular disease and hypertension. Its epidemiology remains unclear due to the high rate of coexistence between DM and hypertension. Therefore, this study aimed to examine the prevalence and clinical characteristics of diabetic cardiomyopathy among patients with acute heart failure (HF). Methods and resultsThis multicenter, retrospective study included 17,614 consecutive patients with acute HF. DM-related HF was defined as HF complicating DM without known manifestations of coronary artery disease, significant valvular heart disease, or congenital heart disease, while diabetic cardiomyopathy was defined as DM-related HF without hypertension. Univariable and multivariable logistic regression analyses were performed to identify factors associated with in-hospital mortality. Diabetic cardiomyopathy prevalence was 1.6 % in the entire cohort, 5.2 % in patients with acute HF complicating DM, and 10 % in patients with DM-related HF. Clinical characteristics, including the presence of comorbidities, laboratory data on admission, and factors associated with in-hospital mortality, significantly differed between the diabetic cardiomyopathy group and the DM-related HF with hypertension group. The in-hospital mortality rate was significantly higher in patients with diabetic cardiomyopathy than in patients with DM-related HF with hypertension (7.7 % vs. 2.8 %, respectively; P < 0.001). ConclusionThe prevalence of diabetic cardiomyopathy was 1.6 % in patients with acute HF, and patients with diabetic cardiomyopathy were at high risk for in-hospital mortality. The clinical characteristics of patients with diabetic cardiomyopathy were significantly different than those of patients with DM-related HF with hypertension.

Esaxerenone Protects against Diabetic Cardiomyopathy via Inhibition of the Chemokine and PI3K-Akt Signaling Pathway.

(1) Background: Diabetic cardiomyopathy (DCM) is a unique form of cardiomyopathy that develops as a consequence of diabetes and significantly contributes to heart failure in patients. Esaxerenone, a selective non-steroidal mineralocorticoid receptor antagonist, has demonstrated potential in reducing the incidence of cardiovascular and renal events in individuals with chronic kidney and diabetes disease. However, the exact protective effects of esaxerenone in the context of DCM are still unclear. (2) Methods: The DCM model was successfully induced in mice by administering streptozotocin (55 mg/kg per day) for five consecutive days. After being fed a normal diet for 16 weeks, echocardiography was performed to confirm the successful establishment of the DCM model. Subsequent sequencing and gene expression analysis revealed significant differences in gene expression in the DCM group. These differentially expressed genes were identified as potential targets for DCM. By utilizing the Swiss Target Prediction platform, we employed predictive analysis to identify the potential targets of esaxerenone. A protein-protein-interaction (PPI) network was constructed using the common targets of esaxerenone and DCM. Enrichment analysis was conducted using Metascape. (3) Results: Compared to the control, the diabetic group exhibited impaired cardiac function and myocardial fibrosis. There was a total of 36 common targets, with 5 key targets. Enrichment analysis revealed that the chemokine and PI3K-Akt signaling pathway was considered a crucial pathway. A target-pathway network was established, from which seven key targets were identified. All key targets exhibited good binding characteristics when interacting with esaxerenone. (4) Conclusion: The findings of this study suggest that esaxerenone exhibits a favorable therapeutic effect on DCM, primarily by modulating the chemokine and PI3K-Akt signaling pathway.

Irisin Alleviates Inflammatory Injury in Diabetic Cardiomyopathy by Regulating NF-κB Pathway

To investigate the protective effect of irisin in diabetic cardiomyopathy (DCM) and its mechanism. A mouse model of DCM was established by high-fat diet combined with the injection of streptozotocin. The mice were assigned to a control group, a DCM group, a DCM+low-dose irisin group, a DCM+high-dose irisin group, and a DCM+pyrrolidine dithiocarbamate (PDTC) (nuclear factor [NF]-κB inhibitor) group. Then, the mice received irisin intervention for 3 weeks after successful modeling. Myocardial morphologic changes were observed by hematoxylin and eosin (HE) staining and Masson staining. The levels of serum creatine kinase (CK) and creatine kinase isoenzyme CK-MB were examined by automatic biochemical analyzer. H9c2 cells were divided into the control group, high glucose and high lipid (HG/HL) group, HG/HL+low-dose irisin group, HG/HL+high-dose irisin group, and HG/HL+PDTC group. CCK-8 assay was conducted to determine cell viability. The expression levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6 in the myocardial tissue and the cells were determined by ELISA. In addition, nuclear translocation of NF-κB p65 protein and the protein expression level of NF-κB inhibitor protein α (IκBα) in the myocardial tissue and the cells were determined by Western blot. According to the results of animal experiment, low and high doses of irisin could alleviate the pathological injury and fibrosis of myocardial tissue to varying degrees. Irisin inhibited the levels of CK, CK-MB, and inflammatory factors, up-regulated IκB protein expression, and diminished NF-κB nuclear translocation. According to the results of cell experiment, low and high doses of irisin could enhance H9c2 cell viability to varying degrees, increase the level of intracellular IκB proteins, and inhibit NF-κB p65 nuclear translocation and inflammatory factor expression. The changes in these aspects in the DCM+low-dose irisin group and the DCM+high-dose irisin group were similar to those in the DCM+PDTC group. Through inhibiting NF-κB p65 nuclear translocation, irisin may reduce the inflammatory response in the myocardial tissue of DCM mice and H9c2 cells of myocardial injury induced by high glucose and high fat, thereby exerting a protective effect on myocardium.

Independent and combined effects of liraglutide and aerobic interval training on glycemic control and cardiac protection in diabetic cardiomyopathy rats

ObjectiveThis study intended to explore the hypoglycemic and cardioprotective effects of 8-week aerobic interval training combined with liraglutide and elucidate the underlying mechanisms. MethodMale Wistar rats were randomly divided into 5 groups - normal control group (CON), diabetic cardiomyopathy group (DCM), high-dose liraglutide group (DH), low-dose liraglutide group (DL), and aerobic interval training combined with liraglutide group (DLE). High-fat diet and streptozotocin (STZ) were used to induce the DCM model, and both the liraglutide administration group and combination therapy group allocated to 8 weeks of either liraglutide or liraglutide and exercise intervention. Cardiac functions were analyzed by electrocardiography. Blood biochemical parameters were measured to judge glycemic control conditions. Hematoxylin and eosin (HE) staining and Sirus red staining was used to identify cardiac morphology and collagen accumulation, respectively. Advanced glycation end products (AGEs) were determined by enzymatic methods. The mRNA expression of myocardial remodeling genes (BNP, GSK3β, α-MHC, β-MHC and PPARα) and the protein expression of GLP-1, GLP-1R were analyzed. ResultsDCM rats developed hyperglycemia, impaired cardiac function with accumulation of AGEs and collagen (P < 0.05). The development of hyperglycemia and cardiac dysfunction was significantly attenuated with all interventions, as reduced cardiac fibrosis and improved cardiac function (P < 0.05). Cardiac remodeling genes were normalized after all interventions, these positive modifications were due to increased GLP-1 and GLP-1R expression in DCM heart (P < 0.05). Liraglutide combined with AIT significantly increased the diameters of cardiomyocytes, increased the α-MHC expressionx, reduced PPARαexpression and reduced the fluctuation of blood glucose level, which showed the safety and effective of medicine combined with exercise. ConclusionLiraglutide combined with AIT intervention normalized blood glucose alleviates myocardial fibrosis and improves cardiac contractile function in DCM rats, supporting the efficacy and safety of the combination therapy.

Trimethylamine N-oxide facilitates the progression of atrial fibrillation in rats with type 2 diabetes by aggravating cardiac inflammation and connexin remodeling.

Diabetes is an independent risk factor for atrial fibrillation (AF). This study aimed to elucidate the pathophysiology of diabetes-related AF from the perspective of the gut microbial metabolite trimethylamine N-oxide (TMAO). In the present study, male rats received either a normal diet to serve as the control group or a high-fat diet/streptozotocin to induce type 2 diabetes mellitus. Then, diabetic rats were divided into two groups based on the presence or absence of 3,3-dimethyl-1-butanol (DMB, a specific TMAO inhibitor) in drinking water: the diabetic cardiomyopathy (DCM) group and the DCM + DMB group. Eight weeks later, compared with control rats, rats in the DCM group exhibited gut microbiota dysbiosis and systemic TMAO elevation. The inflammatory cytokines IL-1β, IL-6, and TNF-α were markedly increased in the atria of rats in the DCM group. Downregulated expression of connexin 40 and lateralized distribution of connexin 43 were also observed in the atria of DCM rats. AF inducibility was significantly higher in DCM rats than in control rats. Furthermore, DMB treatment effectively ameliorated atrial inflammation and connexin remodeling while markedly reducing plasma TMAO levels. DMB treatment also decreased the vulnerability of diabetic rats to AF. In conclusion, TMAO might promote atrial inflammation and connexin remodeling in the development of diabetes, which may play a key role in mediating diabetes-related AF.

Investigation on the differentially expressed circular RNAs in myocardium of mice with diabetic cardiomyopathy

Objective: To identify the differentially expressed circular RNA (circRNA) in the myocardium of diabetic cardiomyopathy (DCM) mice, and analyze their possible biological functions and related regulatory network. Methods: C57BL/6 mice, aged 8 weeks, and weighing were 21-27 g. Eight mice were selected as the control group and 15 mice were selected as the experimental group. The diabetic mice model was established by intraperitoneal injection of streptozotocin in the experimental group. One week after injection, the fasting blood glucose level of mice was measured, and 12 diabetic mice were included in the final experimental group. All mice were fed for 12 weeks under the same laboratory conditions. The cardiac structure and function were detected by echocardiography. Diabetic mice with the left ventricular ejection fraction less than 60% and the E/A less than 1.6 were selected as DCM group (n=3). Mice in DCM group and control group were then sacrificed under deep anesthesia. RNA was extracted from myocardial tissue. High-throughput RNA sequencing technology was used to sequence and identify the RNA in the myocardial tissue of DCM group and normal control group, and the difference was analyzed by DeSeq2. The analysis results were verified at the tissue level by RT-qPCR, and the differential circRNA were analyzed by GO and KEGG pathway analysis. The differentially expressed circRNA-microRNA(miRNA) interaction was predicted by the miRNA target gene prediction software. Results: A total of 63 differentially expressed circRNAs were found in the myocardium of DCM mice. The results of RT-qPCR showed that the tissue level expression of 8 differentially expressed circRNAs was consistent with the sequencing results, of which 7 were up-regulated and 1 was down-regulated. KEGG pathway analysis showed that the up-regulated circRNAs was mainly related to AMPK signal pathway and intercellular adhesion junction pathway, and the down-regulated circRNA was mainly related to cardiomyopathy. Go analysis showed that the up-regulated circRNA was mainly related to the binding process of ions, proteins, kinases and other factors in terms of molecular function, and was involved in regulating the intracellular structure, especially the composition of organelles in terms of cell components. The functional analysis of molecular function and cell components showed that the up-regulated circRNA were related to the cell component origin, recruitment and tissue, and thus participated in the regulation of cell biological process. The down regulated circRNA was related to catalytic activity in terms of molecular function, protein kinase binding process, transferase and calmodulin activity, and was closely related to the components of contractile fibers and the composition of myofibrils. These differentially expressed circRNAs were also related to biological processes such as lysine peptide modification, sarcomere composition, myofibril assembly, morphological development of myocardial tissue, myocardial hypertrophy and so on. Conclusions: In this study, we detected the novel differentially expressed circRNAs in the myocardium of DCM mice, and bioinformatics analysis confirmed that these circRNAs are related to oxidative stress, fibrosis and death of cardiomyocytes, and finally participate in the pathophysiological process of DCM.

Renal denervation ameliorates cardiac metabolic remodeling in diabetic cardiomyopathy rats by suppressing renal SGLT2 expression

AbstractThis study aimed to investigate the effects of renal denervation (RDN) on diabetic cardiomyopathy (DCM) and explore the related mechanisms. Male Sprague-Dawley rats were fed high-fat chow and injected with low-dose streptozotocin to establish a DCM model. Six rats served as controls. The surviving rats were divided into three groups: control group, DCM group and DCM + RDN group. RDN surgery was performed in the fifth week. At the end of the experiment, all rats were subjected to 18F-FDG PET/CT and metabolic cage studies. Cardiac function and structure were evaluated by echocardiography and histology. Myocardial substrate metabolism and mitochondrial function were assessed by multiple methods. In the 13th week, the DCM rats exhibited cardiac hypertrophy and interstitial fibrosis accompanied by diastolic dysfunction. RDN ameliorated DCM-induced cardiac dysfunction (E/A ratio: RDN 1.07 ± 0.18 vs. DCM 0.93 ± 0.12, P < 0.05; E/E' ratio: RDN 10.74 ± 2.48 vs. DCM 13.25 ± 1.99, P < 0.05) and pathological remodeling (collagen volume fraction: RDN 5.05 ± 2.05% vs. DCM 10.62 ± 2.68%, P < 0.05). Abnormal myocardial metabolism in DCM rats was characterized by suppressed glucose metabolism and elevated lipid metabolism. RDN increased myocardial glucose uptake and oxidation while reducing the absorption and utilization of fatty acids. Meanwhile, DCM decreased mitochondrial ATP content, depolarized the membrane potential and inhibited the activity of respiratory chain complexes, but RDN attenuated this mitochondrial damage (ATP: RDN 30.98 ± 7.33 μmol/gprot vs. DCM 22.89 ± 5.90 μmol/gprot, P < 0.05; complexes I, III and IV activity: RDN vs. DCM, P < 0.05). Furthermore, both SGLT2 inhibitor and the combination treatment produced similar effects as RDN alone. Thus, RDN prevented DCM-induced cardiac dysfunction and pathological remodeling, which is related to the improvement of metabolic disorders and mitochondrial dysfunction.Diabetic cardiomyopathy is a serious diabetes-related cardiovascular complication, which is closely related to myocardial metabolic disorders, but there is no specific therapy currently. Renal denervation (RDN), a novel technique to remove renal sympathetic nerves, can reduce the overexpression of renal SGLT2 in diabetic rats, thereby promoting urinary glucose excretion and maintaining systemic glucose homeostasis. On this basis, RDN ameliorated diabetes-induced cardiac metabolic disorders and mitochondrial damages, ultimately preventing diabetes-induced cardiac dysfunction and pathological remodeling.

Protective Effects of Ginsenoside Rb1 in Rats with Diabetic Cardiomyopathy

Ginsenosides play an important role in the treatment of diabetes and obesity. Our group predicted that ginsenoside Rb1 combined with insulin would have a protective effect in diabetic cardiomyopathy. Diabetic model was established by high fat feeding combined with intraperitoneal injection of 70 mg/ kg streptozotocin in 8 w old male Sprague-Dawley rats. One rat was sacrificed at 8 w, 12 w and 14 w, respectively. The cardiac function and pathological structure of the myocardium were observed. It was concluded that the model of the diabetic cardiomyopathy group was successful. Rats were randomly divided into 4 groups and treated with different doses for 6 w. During this period, all rats received regular blood from the tail vein, had regular random blood glucose measurements and had regular fasting body weight measurements. After 6 w of intervention, cardiac ultrasonography was performed to evaluate cardiac function in all groups. Blood samples of aorta were collected for biochemical detection and pathological staining, immunohistochemical staining, reverse transcription polymerase chain reaction, Western blot and enzyme-linked immunosorbent assay were taken from heart tissue samples for detection. Compared with the normal group, diabetic cardiomyopathy rats displayed severe hyperglycemia, lower body weight, poorer cardiac performance, cardiac fibrosis and cardiac inflammation. Diabetic cardiomyopathy rats suffered obvious effects from over-activation of the heparin-binding epidermal growth factor pathway. Ginsenoside Rb1 treatment attenuated hyperglycemia, body weight loss and cardiac injury as well as heparin-binding epidermal growth factor activation induced by diabetic cardiomyopathy. Meanwhile, ginsenoside Rb1 had no obvious toxicity or side effects in the heart, liver or kidneys. Ginsenoside Rb1 treatment in diabetic rats can inhibit the over-activated heparin-binding epidermal growth factor signaling pathway, attenuate fibrosis of myocardial tissue and improve cardiac function, and has no obvious toxicity or side effects. It is a potential drug for diabetic heart disease.

Cathelicidin-WA ameliorates diabetic cardiomyopathy by inhibiting the NLRP3 inflammasome

ABSTRACT Cathelicidin-WA (CWA) is a novel cathelicidin peptide isolated from snakes that has been suggested to exert anti-inflammatory effects. The aim of our study was to investigate whether cathelicidin-WA (CWA) could protect the heart from diabetic cardiomyopathy (DCM). Streptozotocin (STZ) injection was used to establish a mouse model of DCM. CWA peptide (2 mg/kg or 8 mg/kg) was continuously administered to the mice from 10 weeks to 16 weeks after STZ injection. The mice in the DCM group exhibited cardiac dysfunction, while 8 mg/kg CWA ameliorated this cardiac dysfunction. Cardiac fibrosis, inflammation, and oxidative stress as well as cardiomyocyte apoptosis in the DCM mice were decreased by treatment with 8 mg/kg CWA. We isolated neonatal rat cardiomyocytes and stimulated the cells with high glucose to establish an in vitro model of myocyte cell injury. Consistently, CWA inhibited high glucose-induced cell death, inflammation and oxidative stress in the myocytes. Moreover, CWA reduced the formation of the NLR family pyrin domain-containing 3 (NRLP3) inflammasome by regulating thioredoxin-interacting protein expression and p65 activation. NLRP3 overexpression inhibited the beneficial effects of CWA on the heart during DCM and on high glucose-induced myocyte injury. In summary, CWA attenuates cardiac injury and preserves cardiac function during DCM by targeting the NLRP3 pathway. Abbreviations: AAV9: Adeno associated virus; AGE: Advanced Glycation End products; CWA: Cathelicidin-WA; DCM: diabetic cardiomyopathy; Gpx: glutathione peroxidase; HG: high glucose; IL: Interleukin; NLR: Family Pyrin Domain Containing 3 (NRLP3); TXNIP: Thioredoxin interacting protein; LVEF: left ventricular ejection fraction; MDA: Malondialdehyde; MnSOD: manganese superoxide dismutase; NADPH: Nicotinamide adenine dinucleotide phosphate; NAC: N-acetyl-cysteine; NRCMs: Neonatal rat cardiomyocytes; ROS: reactive oxygen species; STZ: Streptozotocin; TNFa: tumor necrosis factor a.

Apocynin attenuates diabetic cardiomyopathy by suppressing ASK1-p38/JNK signaling

Diabetic cardiomyopathy (DCM) significantly increased the morbidity of heart failure in diabetic patients. Long-time oxidative stress is an indisputable contributor for DCM development. Apocynin (APO) has been suggested to be a potential drug against oxidative stress. The study aims to find out the effects of APO on DCM and the related mechanisms. Mice were randomly divided into four groups: control (CON), APO, DCM and DCM + APO. Echocardiography analyses, histological analyses, Western blot and RT-PCR were used to explore the roles and mechanisms of APO in DCM. Isolated neonatal rat cardiomyocytes (NRCMs) and cardiac fibroblasts (CFs) were used for further confirming the APO treatment effects in vitro. Deteriorated cardiac function, enlarged cardiomyocytes, excess cardiac fibrosis and significant cardiac oxidative stress were observed in DCM group. However, APO treatment successfully improved cardiac function, decreased cardiac hypertrophy and fibrosis, and depressed oxidative stress. Mechanistically, APO treatment markedly suppressed apoptosis signal regulating kinase 1(ASK1)-p38/c-jun N-terminal kinase (JNK) signaling and reduced apoptosis. It also inhibited NRCM apoptosis and CF activation via depressing ASK1-p38/JNK signaling in vitro. Moreover, adenovirus-mediated ASK1 overexpression completely removed the protection of APO in vitro. In conclusion, APO treatment could effectively attenuate DCM-associated injuries in vivo and protect against high glucose-induced NRCM and CF injuries in vitro via suppressing ASK1-p38/JNK signaling. APO might be a potential ASK1 inhibitor for treating DCM.

Pharmacokinetic characteristics of hydroxysafflor yellow A in normal and diabetic cardiomyopathy mice.

Hydroxysafflor yellow A (HSYA), a major active water-soluble component in Carthamus tinctorius L., is considered a potential antioxidant with protective effects against myocardial injury. However, its pharmacokinetic characteristics in normal and diabetic cardiomyopathy (DCM) mice remain unknown. This study was designed to investigate the differences in the pharmacokinetics of HSYA between normal and streptozotocin-induced DCM mice. HSYA in the mouse plasma was quantified using LC-MS/MS. Compared with the normal group, the DCM group showed a significantly higher area under the curve (AUC(0-t) , AUC(0-∞) ) value and peak plasma concentration, suggesting a higher uptake of HSYA in the DCM mice, and a significantly lower plasma clearance and apparent volume of distribution, suggesting slower elimination of HSYA in the DCM mice. The levels of serum superoxide dismutase and glutathione peroxidase were significantly higher, and malondialdehyde content was significantly lower in DCM mice than in normal mice, indicating the antioxidative stress effect of HSYA. Furthermore, the correlation analysis revealed that the serum HSYA content in the DCM mice significantly positively correlated with antioxidant enzyme levels. These results showed that the pharmacokinetics of HSYA changed significantly in the DCM mice, and this may improve the antioxidative stress effect of the drug.

Yes-Associated Protein is Involved in Myocardial Fibrosis in Rats with Diabetic Cardiomyopathy.

IntroductionRecent studies have shown that YAP is closely related to the pathological process of cardiovascular diseases. But the role of YAP in cardiac injury of diabetic cardiomyopathy (DCM) is still unclear.MethodsDiabetic cardiomyopathy rat model was established and divided into control group, DCM group, LV-SC-shRNA group and LV-YAP-shRNA group. LV-SC-shRNA group and LV-YAP-shRNA group were injected with lentivirus expressing SC-shRNA and YAP-shRNA via tail vein, respectively. Primary rat cardiac fibroblasts (CFs) were stimulated with high concentration of glucose and treated with recombinant lentivirus expressing either SC-shRNA or YAP-shRNA to observe the expression of CTGF and fibronectin, so as to observe the effect of inhibiting YAP on the pathogenesis of DCM.ResultsCompared with control group, high glucose markedly increased YAP mRNA and protein expression in DCM and CFs. Inhibition of YAP decreased myocardial fibrosis and improved cardiac function in the DCM model and decreased the expression of CTGF and fibronectin in CFs. The result suggested that YAP plays a key role in the pathological progression of DCM, and the underlying mechanisms may be associated with TEAD and CTGF.DiscussionWe found that the expression of YAP was increased both in vivo and in vitro, suggesting that YAP is closely related to DCM, and YAP knockdown can reduce myocardial fibrosis in rat model of DCM by reducing the expression of PAI-1, collagen I, collagen III, CTGF and profilin, as well as the expression of CTGF and fibronectin in CFs. This study revealed that YAP plays an important role in the pathological process of diabetic cardiomyopathy, and down-regulation of YAP expression may provide a new therapeutic target for DCM.

Effect of Musk Tongxin Dropping Pill on Myocardial Remodeling and Microcirculation Dysfunction in Diabetic Cardiomyopathy.

Objective To explore the effect of Musk Tongxin Dropping Pill (MTDP) on myocardial remodeling and microcirculation dysfunction in diabetic cardiomyopathy (DCM). Methods Forty male SD rats were randomly divided into control group (control group, n = 10), DCM model group (DCM group, n = 10), DCM model + pioglitazone group (DCM + PLZ group, n = 10), and DCM model + MTDP group (DCM + MTDP group, n = 10). An intraperitoneal single injection of 65 mg/kg streptozotocin (STZ) was used to establish rat model of DCM and the rats in control group were treated with the same dose of sodium citrate buffer solution. DCM + PLZ group was treated with 3 mg/kg/d PLZ by ig after modeling, DCM + MTDP group was treated with 22 mg/kg/d MTDP by ig, and DCM group was treated with 2 ml/kg/d sodium carboxymethyl cellulose (CMC-Na) by ig. The general condition of rats was continuously observed. After intervening for 3 weeks, the random blood glucose of rats was detected by tail vein, and the echocardiography examination was performed. Blood specimens were collected from the abdominal aorta, serum nitric oxide (NO) and endothelin-1 (ET-1) were detected to estimate endothelial function, and tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), IL-1β, malondialdehyde (MDA), and superoxide dismutase (SOD) were detected to observe the changes of inflammation and oxidative stress indexes. The heart mass index (HMI) was calculated through the ratio of heart mass (HM) to the corresponding body mass (BM). Myocardial pathological tissue staining was performed. Results Compared with control group, blood glucose in other three groups was higher. Left ventricular end systolic diameter (LVSD) and left ventricular end diastolic diameter (LVDD) in DCM group showed a significant increase, while left ventricular ejection fraction (LVEF) and heart rate (HR) in this group displayed an obvious decrease (P < 0.01). BM and HM in DCM group exhibited a reduction, and HM/BM × 103 revealed an apparent increase (P < 0.01). The levels of serum NO and SOD were distinctly downregulated (P < 0.01), and the levels of ET-1, MDA, TNF-α, IL-1β, and IL-6 were remarkably upregulated (P < 0.01). Compared with DCM group, a significant decrease was observed in LVSD and LVDD in DCM + MTDP group, while LVEF and HR obviously increased (P < 0.05). BM and HM indicated an apparent increase, but HM/BM ×103 reduced distinctly (P < 0.01). The levels of serum NO and SOD were markedly upregulated (P < 0.05), and the levels of ET-1, MDA, TNF-α, IL-1β, and IL-6 were significantly downregulated (P < 0.05). HE staining showed that myocardial cells arranged neatly in the control group but not in the DCM group. The intercellular space between myocardial cells in DCM group increased, accompanied by damage of myocardial fibers and infiltration of inflammatory cells. Masson staining displayed an increase in interstitial collagen fibers in DCM group. Carstairs staining showed that microembolization occurred in the myocardium in DCM group, while in DCM + MTDP and DCM + PLZ groups the corresponding myocardial pathological changes were significantly improved. Conclusions MTDP might show a positive effect on myocardial remodeling and microcirculation dysfunction in DCM rats.

Effects of PPARγ agonist pioglitazone on cardiac fibrosis in diabetic mice by regulating PTEN/AKT/FAK pathway.

The aim of this study was to explore the role of pioglitazone (PIO), a peroxisome proliferator-activated receptor-gamma (PPARγ) agonist, in cardiac fibrosis of diabetic mice. A total of 60 adult male C57/B6 mice were divided into 3 groups using a random number table, namely, control group (Sham group, n=20), diabetic cardiomyopathy group (DCM group, n=20), DCM + PIO group (n=20). Streptozocin (STZ) was injected into mice at a dose of 125 mg/Kg to induce the model of diabetes in vivo. After successful induction, mice in DCM + PIO group were intragastrically given PIO at 10 mg/kg/d once a day for 6 weeks. Meanwhile, those in Sham group and DCM group were given the same volume of normal saline. After 6 weeks, ejection fraction % (EF%), fraction shortening % (FS%) and heart rate of mice in each group were examined via echocardiography. Picrosirius red (PSR) staining assay was conducted to detect collagen deposition in myocardial tissues of mice in each group. The protein expression level of PPARγ in mouse myocardial tissues in each group was measured through Western blotting and immunohistochemical staining assays. Hematoxylin-eosin (H&E) staining assay was carried out to evaluate the myocardial hypertrophy of mice in each group. The protein expression level of transforming growth factor-β (TGF-β) in mouse myocardial tissues in each group was measured through immunohistochemical staining assay. In addition, Western blotting was employed to detect the expression of proteins related to the phosphate and tension homology deleted on chromsome ten (PTEN)/protein kinase B (AKT)/focal adhesion kinase (FAK) signaling pathway in myocardial tissues of mice in each group. The messenger ribonucleic acid (mRNA) and protein expression levels of PPARγ in mouse myocardial tissues were significantly lower in DCM group than those in Sham group (p<0.05). PPARγ agonist PIO could significantly increase the protein expression of PPARγ in myocardial tissues of DCM mice. The results of cardiac Doppler ultrasound revealed that PIO significantly upregulated EF% and FS% in DCM mice (p<0.05). Besides, PIO remarkably reduced collagen deposition and TGF-β protein expression in myocardial tissues in DCM mice (p<0.05). H&E staining results showed that PIO notably attenuated myocardial hypertrophy in DCM mice (p<0.05). Furthermore, it was discovered that PIO markedly elevated PTEN protein in myocardial tissues of DCM mice and inhibited the phosphorylation of AKT and FAK proteins (p<0.05). The protective effect of PIO against cardiac fibrosis in diabetic mice may be related to its regulation on the PTEN/AKT/FAK signaling pathway. Our findings suggest that PIO is expected to become a targeted drug for the treatment of DCM in clinical practice.

Label-free and noninvasive method for assessing the metabolic status in type 2 diabetic rats with myocardium diastolic dysfunction.

This study assesses the metabolic status of rat diabetic cardiomyopathy (DCM) models. Echocardiography is used to detect the diastolic dysfunction in type 2 diabetic rats, and a lower threshold for inducible atrial fibrillation is found in type 2 diabetic rats with diastolic dysfunction compared to the control. Metabolic abnormalities are detected by status changes of reduced nicotinamide adenine dinucleotide (phosphate) (NAD(P)H), which is an essential coenzyme in cells or tissues. Fluorescence lifetime imaging microscopy (FLIM) is used to monitor changes in NAD(P)H in both myocardial tissues and blood. FLIM reveals that the protein-bound proportion of NAD(P)H in rat myocardium in the DCM group is smaller than the control group, which indicates the oxidative phosphorylation rate of the DCM group decreased. Similar results are found for blood plasma of DCM rats by the FLIM study. FLIM exhibits high potential for screening DCM as a label-free, sensitive, and noninvasive method.

MiR-34a attenuates myocardial fibrosis in diabetic cardiomyopathy mice via targeting Pin-1.

Diabetic cardiomyopathy (DCM) is characterized by myocardial hypertrophy and fibrosis. This study aimed to investigate the effects of microRNA (miR)-34a on myocardial fibrosis in DCM and its potential mechanism of targeting Pin-1 signaling. Vimentin and Pin-1 proteins in mouse cardiac tissues were detected by immunohistochemical staining. Locked nucleic acid in situ hybridization was used to measure miR-34a expression in cardiac tissues. Primary mouse cardiac fibroblasts (CFs) were transfected with a mimics control/miR-34a mimics or Pin-1 plasmid and cultured in high-glucose (HG) Dulbecco's modified Eagle's medium. The miR-34a levels were measured by quantitative polymerase chain reaction. The apoptosis and viability of transfected cells were detected by the terminal deoxynucleotidyl transferase dUTP nick end labeling and Cell Counting Kit-8 assays respectively. A cell migration experiment and dual-luciferase reporter assay were also performed. The body weight and fasting blood glucose of DCM mice were significantly higher than those in the control (CTL) group. In addition, DCM mice had decreased serum insulin levels and impaired cardiac function. The number of CFs in the DCM group was higher than in the CTL group and Pin-1 expression was upregulated. The expression level of miR-34a in the cardiac tissue of mice in the DCM group was obviously downregulated compared with the CTL group. The HG stimulation of CFs for 48 h significantly downregulated the expression level of miR-34a and was associated with increased Type I collagen expression, cell viability, and migration and decreased apoptosis. However, these effects could be reversed by overexpressing miR-34a in HG-induced CFs. Furthermore, we found that Pin-1 was a direct target of miR-34a. Our results suggest that miR-34a can attenuate myocardial fibrosis in DCM by reducing Type I collagen production, cell viability, and migration and increasing the apoptosis of CFs by targeting Pin-1 signaling.