Atorvastatin alleviates experimental diabetic cardiomyopathy by suppressing apoptosis and oxidative stress

Programmed death of cardiomyocytes in cardiovascular disease and new therapeutic approaches

Cardiovascular diseases (CVDs) have a complex pathogenesis and pose a major threat to human health. Cardiomyocytes have a low regenerative capacity, and their death is a key factor in the morbidity and mortality of many CVDs. Cardiomyocyte death can be regulated by specific signaling pathways known as programmed cell death (PCD), including apoptosis, necroptosis, autophagy, pyroptosis, and ferroptosis, etc. Abnormalities in PCD can lead to the development of a variety of cardiovascular diseases, and there are also molecular-level interconnections between different PCD pathways under the same cardiovascular disease model. Currently, the link between programmed cell death in cardiomyocytes and cardiovascular disease is not fully understood. This review describes the molecular mechanisms of programmed death and the impact of cardiomyocyte death on cardiovascular disease development. Emphasis is placed on a summary of drugs and potential therapeutic approaches that can be used to treat cardiovascular disease by targeting and blocking programmed cell death in cardiomyocytes.

Multidirectional Intervention of Chinese Herbal Medicine in the Prevention and Treatment of Atherosclerosis: From Endothelial Protection to Immunomodulation

Atherosclerosis is a significant risk factor for developing cardiovascular disease and a leading cause of death worldwide. The occurrence of atherosclerosis is closely related to factors such as endothelial injury, lipid deposition, immunity, and inflammation. Conventional statins, currently used in atherosclerosis treatment, have numerous adverse side effects that limit their clinical utility, prompting the urgent need to identify safer and more effective therapeutic alternatives. Growing evidence indicates the significant potential of Chinese herbs in atherosclerosis treatment. Herbal monomer components, such as natural flavonoid compounds extracted from herbs like Coptis chinensis and Panax notoginseng, have been utilized for their lipid-lowering and inflammation-inhibiting effects in atherosclerosis treatment. These herbs can be used as single components in treating diseases and with other Chinese medicines to form herbal combinations. This approach targets the disease mechanism in multiple ways, enhancing the therapeutic effects. Thus, this review examines the roles of Chinese herbal medicine monomers and Chinese herbal compounds in inhibiting atherosclerosis, including regulating lipids, improving endothelial function, reducing oxidative stress, regulating inflammation and the immune response, and apoptosis. By highlighting these roles, our study offers new perspectives on atherosclerosis treatment with Chinese herbs and is anticipated to contribute to advancements in related research fields.

NF-ĸB axis in diabetic neuropathy, cardiomyopathy and nephropathy: A roadmap from molecular intervention to therapeutic strategies

Diabetes mellitus (DM) is a metabolic illness defined by elevated blood glucose levels, mediating various tissue alterations, including the dysfunction of vital organs. Diabetes mellitus (DM) can lead to many consequences that specifically affect the brain, heart, and kidneys. These issues are known as neuropathy, cardiomyopathy, and nephropathy, respectively. Inflammation is acknowledged as a pivotal biological mechanism that contributes to the development of various diabetes consequences. NF-κB modulates inflammation and the immune system at the cellular level. Its abnormal regulation has been identified in several clinical situations, including cancer, inflammatory bowel illnesses, cardiovascular diseases, and Diabetes Mellitus (DM). The purpose of this review is to evaluate the potential impact of NF-κB on complications associated with DM. Enhanced NF-κB activity promotes inflammation, resulting in cellular harm and compromised organ performance. Phytochemicals, which are therapeutic molecules, can potentially decline the NF-κB level, therefore alleviating inflammation and the progression of problems correlated with DM. More importantly, the regulation of NF-κB can be influenced by various factors, such as TLR4 in DM. Highlighting these factors can facilitate the development of novel therapies in the future.

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

ABSTRACT

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.

The latest emerging drugs for the treatment of diabetic cardiomyopathy

INTRODUCTION

Diabetic cardiomyopathy (DCM) is a serious complication of diabetes mellitus involving multiple pathophysiologic mechanisms. In addition to hypoglycemic agents commonly used in diabetes, metabolism-related drugs, natural plant extracts, melatonin, exosomes, and rennin-angiotensin-aldosterone system are cardioprotective in DCM. However, there is a lack of systematic summarization of drugs for DCM.

AREAS COVERED

In this review, the authors systematically summarize the most recent drugs used for the treatment of DCM and discusses them from the perspective of DCM pathophysiological mechanisms.

EXPERT OPINION

We discuss DCM drugs from the perspective of the pathophysiological mechanisms of DCM, mainly including inflammation and metabolism. As a disease with multiple pathophysiological mechanisms, the combination of drugs may be more advantageous, and we have discussed some of the current studies on the combination of drugs.

Atorvastatin ameliorated myocardial fibrosis in db/db mice by inhibiting oxidative stress and modulating macrophage polarization

BACKGROUND

People with diabetes mellitus (DM) suffer from multiple chronic complications due to sustained hyperglycemia, especially diabetic cardiomyopathy (DCM). Oxidative stress and inflammatory cells play crucial roles in the occurrence and progression of myocardial remodeling. Macrophages polarize to two distinct phenotypes: M1 and M2, and such plasticity in phenotypes provide macrophages various biological functions.

AIM

To investigate the effect of atorvastatin on cardiac function of DCM in db/db mice and its underlying mechanisms.

METHODS

DCM mouse models were established and randomly divided into DM, atorvastatin, and metformin groups. C57BL/6 mice were used as the control. Cardiac function was evaluated by echocardiography. Hematoxylin and eosin and Masson staining was used to examine the morphology and collagen fibers in myocardial tissues. The expression of transforming growth factor-β1 (TGF-β1), tumor necrosis factor-α (TNF-α), interleukin-1 β (IL-1β),M1 macrophages (iNOS+), and M2 macrophages (CD206+) were demonstrated by immunohistochemistry and immunofluorescence staining. The levels of TGF-β1, IL-1β, and TNF-α were detected by ELISA and real-time quantitative polymerase chain reaction. Malondialdehyde (MDA) concentrations and superoxide dismutase (SOD) ac-tivities were also measured.

RESULTS

Treatment with atorvastatin alleviated cardiac dysfunction and decreased db/db mice. The broken myocardial fibers and deposition of collagen in the myocardial interstitium were relieved especially by atorvastatin treatment. Atorvastatin also reduced the levels of serum lactate dehydrogenase, creatine kinase isoenzyme, and troponin; lowered the levels of TGF-β1, TNF-α and IL-1β in serum and myocardium; decreased the concentration of MDA and increased SOD activity in myocardium of db/db mice; inhibited M1 macrophages; and promoted M2 macrophages.

CONCLUSION

Administration of atorvastatin attenuates myocardial fibrosis in db/db mice, which may be associated with the antioxidative stress and anti-inflammatory effects of atorvastatin on diabetic myocardium through modulating macrophage polarization.

Cardioprotective role of A-cycloglycosylated derivative of Rubiadin in diabetic cardiomyopathy in rats

Diabetic cardiomyopathy (DCM) is a kind of idiopathic heart disease, which is one of the main complications of diabetes and seriously threatens the life of diabetic patients. Rubiadin, an anthraquinone compound extracted from the stems and roots of rubiaceae, has been widely discussed for its anti-diabetes, anti-oxidation and other pharmacological effects. However, Rubiadin can cause drug-induced liver injury. Therefore, A-cycloglycosylated derivative of Rubiadin (ACDR) was obtained by modifying its structure. The purpose of this study was to investigate the effect of ACDR on DCM cardiac injury and its mechanism. The DCM animal model was established by streptozotocin, and the success of DCM was verified by blood glucose level, echocardiographic evidence of impaired myocardial functions along with enhanced myocardial fibrosis. We performed liver function tests, morphological staining of the heart and tests for oxidative stress to evaluate cardiac functional and structural changes. Finally, the expression of Na⁺/H⁺ exchanger (NHE1) protein was analyzed by immunohistochemistry and western bolt, and the expression of hairy/enhancer-of-split related with YRPW motif 1 (Hey1) and P-p38 protein was detected by immunofluorescence chemistry and western blotting. The results showed that ACDR can improve cardiac dysfunction, reduce myocardial injury, reduce oxidative stress, and protect the liver in DCM rats. Interestingly, all variations were countered by LiCl. Our study suggests that, along with controlling hyperglycemia, ACDR may improve DCM by reducing NHE1 expression, further inhibiting P-p38 activity and increasing Hey1 expression to reduce oxidative stress.

Glycemic Control and the Heart: The Tale of Diabetic Cardiomyopathy Continues

Cardiovascular diseases are the leading cause of death in people with diabetes. Diabetic cardiomyopathy (DC) is an important complication of diabetes and represents a distinct subtype of heart failure that occurs in absence of cardiovascular diseases. Chronic hyperglycemia and hyperinsulinemia along with insulin resistance and inflammatory milieu are the main mechanisms involved in the pathophysiology of DC. Changes in lifestyle favoring healthy dietary patterns and physical activity, combined with more innovative anti-diabetes therapies, are the current treatment strategies to safeguard the cardiovascular system. This review aims at providing an updated comprehensive overview of clinical, pathogenetic, and molecular aspects of DC, with a focus on the effects of anti-hyperglycemic drugs on the prevention of pump dysfunction and consequently on cardiovascular health in type 2 diabetes.

Preliminary evidence for the presence of multiple forms of cell death in diabetes cardiomyopathy

Diabetic mellitus (DM) is a common degenerative chronic metabolic disease often accompanied by severe cardiovascular complications (DCCs) as major causes of death in diabetic patients with diabetic cardiomyopathy (DCM) as the most common DCC. The metabolic disturbance in DCM generates the conditions/substrates and inducers/triggers and activates the signaling molecules and death executioners leading to cardiomyocyte death which accelerates the development of DCM and the degeneration of DCM to heart failure. Various forms of programmed active cell death including apoptosis, pyroptosis, autophagic cell death, autosis, necroptosis, ferroptosis and entosis have been identified and characterized in many types of cardiac disease. Evidence has also been obtained for the presence of multiple forms of cell death in DCM. Most importantly, published animal experiments have demonstrated that suppression of cardiomyocyte death of any forms yields tremendous protective effects on DCM. Herein, we provide the most updated data on the subject of cell death in DCM, critical analysis of published results focusing on the pathophysiological roles of cell death, and pertinent perspectives of future studies.

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.

Combined treatment with ultrasound-targeted microbubble destruction technique and NM-aFGF-loaded PEG-nanoliposomes protects against diabetic cardiomyopathy-induced oxidative stress by activating the AKT/GSK-3β1/Nrf-2 pathway

The present study sought to investigate the effect of non-mitogenic acidic fibroblast growth factor (NM-aFGF) loaded PEGylated nanoliposomes (NM-aFGF-PEG-lips) combined with the ultrasound-targeted microbubble destruction (UTMD) technique on modulating diabetic cardiomyopathy (DCM)and the mechanism involved. Animal studies showed that the diabetes mellitus (DM) group exhibited typical myocardial structural and functional changes of DCM. The indexes from the transthoracic echocardiography showed that the left ventricular function in the NM-aFGF-PEG-lips + UTMD group was significantly improved compared with the DM group. Histopathological observation further confirmed that the cardiomyocyte structural abnormalities and mitochondria ultrastructural changes were also significantly improved in the NM-aFGF-PEG-lips + UTMD group compared with DM group. The cardiac volume fraction (CVF) and apoptosis index in the NM-aFGF-PEG-lips + UTMD group decreased to 10.31 ± 0.76% and 2.16 ± 0.34, respectively, compared with those in the DM group (CVF = 21.4 ± 2.32, apoptosis index = 11.51 ± 1.24%). Moreover, we also found significantly increased superoxide dismutase (SOD) activity and glutathione peroxidase (GSH-Px) activity as well as clearly decreased lipid hydroperoxide levels and malondialdehyde (MDA) activity in the NM-aFGF-PEG-lips + UTMD group compared with those in the DM group (p < .05). Western blot analysis further revealed the highest level of NM-aFGF, p-AKT, p-GSK-3β1, Nrf-2, SOD2 and NQO1 in the NM-aFGF-PEG-lips + UTMD group. This study confirmed using PEGylated nanoliposomes combined with the UTMD technique can effectively deliver NM-aFGF to the cardiac tissue of diabetic rats. The NM-aFGF can then inhibit myocardial oxidative stress damage due to DM by activating the AKT/GSK/Nrf-2 signaling pathway, which ultimately improved the myocardial structural and functional lesions in diabetic rats.

Combined Administration of Metformin and Atorvastatin Attenuates Diabetic Cardiomyopathy by Inhibiting Inflammation, Apoptosis, and Oxidative Stress in Type 2 Diabetic Mice

Diabetic cardiomyopathy (DCM), a common complication of diabetes mellitus, may eventually leads to irreversible heart failure. Metformin is the cornerstone of diabetes therapy, especially for type 2 diabetes. Statins are widely used to reduce the risk of cardiovascular diseases. In this study, we aimed to investigate whether the combined administration of metformin and atorvastatin could achieve superior protective effects on DCM and to elucidate its molecular mechanism. Here, db/db mice (9–10 weeks old) were randomly divided into four groups, including sterile water group (DM), metformin group (MET, 200 mg/kg/day), atorvastatin group (AVS, 10 mg/kg/day), and combination therapy group (MET + AVS). Mice were treated with different drugs via gavage once per day for 3 months. After 3 months of treatment, the pathological changes (inflammation, fibrosis, hypertrophy, and oxidative stress makers) were detected by histopathological techniques, as well as Western blotting. The H9C2 cardiomyocytes were treated with palmitate (PAL) to mimic diabetic condition. The cells were divided into control group, PAL treatment group, MET + PAL treatment group, AVS + PAL treatment group, and MET + AVS + PAL treatment group. The effects of MET and AVS on the cell viability and inflammation of H9C2 cells subjected to PAL condition were evaluated by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay, immunofluorescence staining, and Western blotting. Both MET and AVS prevented diabetes-induced fibrosis, hypertrophy, and inflammation. The combination therapy showed superior effects in protecting myocardial tissue against diabetes-induced injury. Mechanistically, the combination therapy significantly inhibited oxidative stress and the expression levels of inflammation-related proteins, e.g., NLRP3, caspase-1, interleukin-1β (IL-1β), Toll-like receptor 4 (TLR4), and P-p65/p65, in both cardiac tissues and H9C2 cells. TUNEL assay showed that the combination therapy significantly attenuated the apoptosis of cardiomyocytes; decreased the expression level of pro-apoptotic-related proteins, such as cleaved caspase-3 and BAX; and enhanced the expression level of anti-apoptotic protein (Bcl-2). Furthermore, the combination therapy remarkably upregulated the expression levels of 5′-AMP-activated protein kinase (AMPK) and SIRT1. Our findings indicated that the anti-inflammation and anti-apoptosis effects of the combination therapy may be related to activation of AMPK/SIRT1 signaling pathway.

Impact of liraglutide on microcirculation in experimental diabetic cardiomyopathy

Liraglutide is a new therapy used in diabetes and its effect on diabetic complications particularly cardiovascular ones is still under investigated. In our research, we tried to study the effect of liraglutide on experimental diabetic cardiomyopathy (DCM) induced by streptozotocin. We found that liraglutide nearly preserved normal myocardiac structure and significantly protected against myocardiac inflammation and fibrosis that was found in DCM group, p < 0.05. It also increased the density of coronary arteriolar vasculature markedly indicated by significant increase in α SMA (p < 0.05) compared to both DCM and non-diabetic (ND) groups. Moreover, liraglutide decreased TNFα and increased VEGF proteins expression (P < 0.05) compared to DCM group. Conclusion, liraglutide may have a very important role in protecting against experimentally induced diabetic cardiomyopathy by preventing the degenerative changes in the cardiomyocytes and the associated fibrosis, inflammation and decreased vasculature at structural and molecular levels.

Use of a Systematic Pharmacological Methodology to Explore the Mechanism of Shengmai Powder in Treating Diabetic Cardiomyopathy

BACKGROUND Cardiovascular complications, such as diabetic cardiomyopathy (DCM), are the leading cause of death in diabetic patients. Shengmai Powder (SMP) was found to have cardioprotective effects. MATERIAL AND METHODS Based on the systematic pharmacological methodology, this research determined the genes of DCM and the known targets of SMP, predicted potential compounds and targets of SMP, constructed networks for DCM and SMP, and performed network analysis. RESULTS Five network were constructed: (1) the DCM gene PPI network; (2) the Compound-compound target network of SMP; (3) the SMP-DCM PPI network; (4) the Compound-known target network of SMP; (5) and the SMP known target-DCM PPI network. Several DCM and treatment related targets, clusters, signaling pathways, and biological processes were found. CONCLUSIONS SMP is able to regulate glycometabolism-related, lipid metabolism-related, inflammatory response-related, oxidative stress-related signaling pathways, and biological processes and targets, which suggests that SMP may have a therapeutic effect on DCM.

Impact of vildagliptin on vascular and fibrotic remodeling of myocardium in experimental diabetic cardiomyopathy

The effect of dipeptidyl peptidase-4 inhibitors (DPP-4is) on myocardium in diabetic cardiomyopathy (DCM) remains a matter of debate. In the current study we investigated the effect of vildagliptin (VILDA, 3 mg/kg/d) on myocardium of DCM focusing on coronary microcirculation as well as on endothelial stress markers (ICAM and VCAM). We divided animals equally into 4 groups; nondiabetic (ND), VILDA per se, DCM and DCM + VILDA and their myocardium was evaluated for the fibro-vascular remodeling immunohistochemically as well as for molecular changes. VILDA had reversed the histological changes occurred in DCM including the disintegration, degeneration, and steatosis of cardiomyocytes with disappearance of the edema fluid. In addition VILDA significantly increased (p < 0.05) density of the coronary microcirculation and relieved endothelial stress. However, it did not prevent the development of fibrotic remodeling including the increased collagen deposition and the significantly upregulated (p < 0.05) corresponding genes. Therefore VILDA may have a positive impact on the microvascular remodeling, but not on fibrotic changes, in DCM.

Spleen tyrosine kinase‑induced JNK‑dependent NLRP3 activation is involved in diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) is a leading contributor to the increased morbidity and mortality rates associated with diabetes. Persistent inflammation has previously been reported to be involved in the pathogenesis of DCM. However, the exact underlying molecular mechanisms remain to be fully elucidated. In the present study, the role of spleen tyrosine kinase (Syk) and c‑Jun N‑terminal kinase (JNK) in NLR family pyrin domain‑containing 3 (NLRP3 inflammasome) activation in DCM were investigated in vivo and in vitro. Streptozotocin (65 mg/kg) was injected intraperitoneally into Sprague‑Dawley rats to induce a rat model of diabetes. Neonatal rat cardiomyocytes and H9c2 cells were cultured to detect the expression of JNK, NLRP3 and its associated downstream molecules, following treatment with Syk/JNK inhibitor or Syk/JNK‑small interfering (si)RNA in high glucose (HG) conditions. It was revealed that the protein and mRNA expression levels of phospho (p)‑Syk, p‑JNK, NLRP3 and its associated downstream molecules, including interleukin (IL)‑1β, were upregulated in vivo and in vitro. The JNK inhibitor significantly decreased the expression of NLRP3 and its downstream molecules in neonatal rat cardiomyocytes and H9c2 cells treated with HG. Furthermore, Syk‑siRNA and the Syk inhibitor markedly inhibited the HG‑induced activation of JNK, followed by the downregulation of NLRP3 and its downstream molecules at the mRNA and protein levels in cells. Therefore, it was demonstrated that the HG‑induced activation of NLRP3 was mediated by the activation of Syk/JNK, which subsequently increased the protein expression levels of mature IL‑1β, suggesting that the Syk/JNK/NLRP3 signaling pathway serves a critical role in the pathogenesis of DCM.

Favorable outcomes of metformin on coronary microvasculature in experimental diabetic cardiomyopathy

Although metformin is widely prescribed in diabetes, its use with associated cardiac dysfunction remains debatable. In the current study, we investigated the effect of metformin on coronary microvasculature in experimental diabetic cardiomyopathy (DCM) induced by streptozotocin. Administration of metformin after induction of DCM, reversed almost all cardiomyocyte degenerative changes induced by DCM. Metformin diminished the significantly increased (p < 0.05) collagen deposited in the DCM. In addition metformin had improved the density of the significantly decreased arteriolar (αSMA⁺) and capillary (CD31⁺) coronary microvasculature compared to that of the DCM and non-diabetics (ND) with downregulation of the significantly increased expression (p < 0.05) of COL-I, III, TGF-β, CTGF, ICAM and VCAM genes. Therefore metformin may be beneficial in limiting the fibrotic and the vascular remodeling occurring in DCM at the genetic as well as the structural levels.

miR-30a attenuates cardiac fibrosis in rats with myocardial infarction by inhibiting CTGF

The mechanism of miR-30a in myocardial fibrosis in rats with myocardial infarction (MI) was investigated. rAAV9-miR-30a was constructed and transfected to heart via injecting into the left ventricular cavity of MI rats. The sham operation group, control group, miR-30a group and miR-30a-NC group were established. Besides, the 3′-UTR of CTGF was inserted into luciferase expression plasmid (pMir-report), then transfected into COS1 cells. miR-30a and control miRNA were, respectively, cotransfected into COS1 cells. The expression of luciferase was detected before and after knockdown of the binding site of miR-30a and the 3′-UTR of CTGF. Four weeks after MI surgery, cardiac function was measured by color Doppler echocardiography, including short axis shortening (FS) and left ventricular ejection fraction (LVEF); the myocardial collagen volume fraction (CVF) was observed by Masson's staining; deposition of collagen I and collagen III were evaluated by immunohistochemical stain; using real-time PCR to detect expression levels of miR-30a and CTGF; the expression of CTGF was observed by western blotting. In MI group, cardiac function was significantly improved, while the expression levels of CVF, collagen I and III, the ratio of type I/III collagen, CTGF were significantly reduced. After knockdown the binding site of miR-30a and the 3′-UTR of CTGF, luciferase expression in COS1 cells decreased significantly. miR-30a might inhibit the expression of CTGF by directly combining with the 3′-UTR site of CTGF after MI, thereby reduce the production of collagen in myocardia, inhibit myocardial fibrosis, then improve cardiac function.

Pravastatin improves risk factors but not ischaemic tolerance in obese rats

Statins are effective in management of dyslipidaemia, and a cornerstone of CVD prevention strategies. However, the impacts of their pleiotropic effects on other cardiovascular risk factors and myocardial responses to infarction are not well characterised. We hypothesised that pravastatin treatment in obesity improves lipid profiles, insulin-resistance and myocardial resistance to ischaemia/reperfusion (I/R) injury. Wistar rats were fed a control (C) chow or high carbohydrate and fat diet (HCFD) for 16 weeks with vehicle or pravastatin (prava 7.5 mg/kg/day) treatment for 8 weeks. At 16 weeks HOMAs were performed, blood samples collected and hearts excised for Langendorff perfusions/biochemical analyses. Anti-oxidant activity and proteins regulating mitochondrial fission/fusion and apoptosis were assessed. The HCFD increased body weight (736±15 vs. 655±12 g for C; P<0.001), serum triglycerides (2.91±0.52 vs. 1.64±0.26 mmol/L for C; P<0.001) and insulin-resistance (HOMA- 6.9±0.8 vs. 4.2±0.5 for C; P<0.05) while prava prevented diet induced changes and paradoxically increased lipid peroxidation. The HCFD increased infarct size (34.1±3.1% vs. 18.8±3.0% of AAR for C; P<0.05), which was unchanged by prava in C and HCFD animals. The HCFD decreased cardiac TxR activity and mitochondrial MFN-1 and increased mitochondrial DRP-1 (reducing MFN-1:DRP-1 ratio) and Bax expression, with the latter changes prevented by prava. While unaltered by diet, cytosolic levels of Bax and caspase-3 were reduced by prava in C and HCFD hearts (without changes in cleaved caspase-3). We conclude that obesity, hyper-triglyceridemia and impaired glycemic control in HCFD rats are countered by prava. Despite improved risk factors, prava did not reduce myocardial infarct size, potentially reflecting its complex pleiotropic impacts on cardiac GPX activity and MFN-1, DRP-1, caspase-3 and Bcl-2 proteins.

Ginkgo biloba Leaf Extract Protects against Myocardial Injury via Attenuation of Endoplasmic Reticulum Stress in Streptozotocin-Induced Diabetic ApoE-/- Mice

Diabetes was induced in high-fat diet-fed ApoE^−/− mice via administration of low-dose streptozotocin (STZ) for five days. Mice were then treated with GBE (200 or 400 mg/kg) by gastric gavage daily for 12 weeks. Mice in the untreated diabetic group received saline instead, and nondiabetic C57BL/6J mice served as controls. Collagen І and ІІІ mRNA expression was measured by real-time PCR. TNF-α, IL-1β mRNA levels, and NF-κB expression were determined to analyze intramyocardial inflammation. Hallmarks of endoplasmic reticulum stress- (ERS-) related apoptosis pathways, including phosphorylated c-Jun N-terminal kinase (p-JNK), C/EBP homologous protein (CHOP), caspase-12, and cleaved caspase-3, were analyzed by Western blotting. Diabetic ApoE^−/− myocardial injury was associated with increased cardiomyocyte apoptosis (increased expression of p-JNK, CHOP, caspase-12, and cleaved caspase-3), interstitial fibrosis (increased mRNA levels of collagen І and ІІІ), and inflammation (increased mRNA levels of TNF-α and IL-1β, and NF-κB expression). GBE at 200 and 400 mg/kg/day significantly attenuated cardiomyocyte apoptosis, collagen deposition, and inflammation in diabetic mice via inhibition of the p-JNK, CHOP, and caspase-12 pathways. Serum levels of the proinflammatory cytokines (IL-6, IL-1β, and TNF-α), blood glucose, and lipid profiles were also regulated by GBE treatment. GBE might be beneficial in the treatment of diabetic myocardial injury.

Diabetic retinopathy is associated with diastolic dysfunction in type 2 diabetic patients with non-ischemic dilated cardiomyopathy

BACKGROUND

To investigate the association between diabetic retinopathy (DR) and myocardial dysfunction in patients with type 2 diabetes and dilated cardiomyopathy (dCMP).

METHODS

Data were collected retrospectively from 89 patients with dCMP (46 with type 2 diabetes and 43 without diabetes) and no evidence of coronary artery disease. Echocardiographic parameters and laboratory data, including lipid profiles and fundus findings, were obtained from medical records. A left ventricular ejection fraction (LVEF) less than 40% was considered impaired systolic function, while an E/E' ratio greater than 15 was considered elevated left ventricular (LV) filling pressure.

RESULTS

Baseline characteristics show that LVEF was not significantly different between patients with and without diabetes or between diabetic patients with and without DR. Among the diastolic function parameters, patients with DR exhibited higher E/E' ratios (left ventricular filling pressures) than patients without DR (23.75 ± 13.37 vs 11.71 ± 3.50, P = 0.022). Logistic regression analysis revealed that statin use lowered the risk of impaired systolic dysfunction in all patients (odds ratio (OR) 0.33, 95% confidence interval (CI) 0.12-0.92, P = 0.034) and in patients with diabetes (OR 0.273, 95% CI 0.08-0.99, P = 0.049), while the presence of DR was associated with a higher risk of elevated LV filling filling pressure in patients with diabetes (OR 18.00, 95% CI 1.50-216.62, P = 0.023).

CONCLUSIONS

In conclusion, DR was associated with elevated LV filling pressure in patients with dCMP. DR may not only represent microvascular long-term complications in patients with diabetes but may also be associated with more advanced form of diastolic dysfunction among diabetic patients with cardiomyopathy.

The effect of Astragalus polysaccharides on attenuation of diabetic cardiomyopathy through inhibiting the extrinsic and intrinsic apoptotic pathways in high glucose -stimulated H9C2 cells

Background

Apoptosis plays a critical role in the progression of diabetic cardiomyopathy (DC). Astragalus polysaccharides (APS), an extract of astragalus membranaceus (AM), is an effective cardioprotectant. Currently, little is known about the detailed mechanisms underlying cardioprotective effects of APS. The aims of this study were to investigate the potential effects and mechanisms of APS on apoptosis employing a model of high glucose induction of apoptosis in H9C2 cells.

Methods

A model of high glucose induction of H9C2 cell apoptosis was adopted in this research. The cell viabilities were analyzed by MTT assay, and the apoptotic response was quantified by flow cytometry. The expression levels of the apoptosis related proteins were determined by Real-time PCR and western blotting.

Results

Incubation of H9C2 cells with various concentrations of glucose (i.e., 5.5, 12.5, 25, 33 and 44 mmol/L) for 24 h revealed that cell viability was reduced by high glucose dose-dependently. Pretreatment of cells with APS could inhibit high glucose-induced H9C2 cell apoptosis by decreasing the expressions of caspases and the release of cytochrome C from mitochondria to cytoplasm. Further experiments also showed that APS could modulate the ratio of Bcl-2 to Bax in mitochondria.

Conclusions

APS decreases high glucose-induced H9C2 cell apoptosis by inhibiting the expression of pro-apoptotic proteins of both the extrinsic and intrinsic pathways and modulating the ratio of Bcl-2 to Bax in mitochondria.

Atorvastatin Alleviates Experimental Diabetic Cardiomyopathy by Regulating the GSK-3β-PP2Ac-NF-κB Signaling Axis

Recent studies reported that atorvastatin (ATOR) alleviated progression of experimental diabetic cardiomyopathy (DCM), possibly by protecting against apoptosis. However, the underlying mechanisms of this protective effect remain unclear. Therefore, our study investigated the role of the glycogen synthase kinase (GSK)-3β-protein phosphatase 2A(PP2A)-NF-κB signaling pathway in the anti-apoptotic and cardioprotective effects of ATOR on cardiomyocytes cultured in high glucose (HG) and in DCM. Our results showed that, in HG-cultured cardiomyocytes, phosphorylation of GSK-3β was decreased, while that of the PP2A catalytic subunit C (PP2Ac) and IKK/IкBα was increased, followed by NF-кB nuclear translocation and apoptosis. IKK/IкBα phosphorylation and NF-кB nuclear translocation were also increased by treatment of cells with okadaic acid (OA), a selective PP2A inhibitor, or by silencing PP2Ac expression. The opposite results were obtained by silencing GSK-3β expression, which resulted in PP2Ac activation. Furthermore, IKK/IкBα phosphorylation and NF-кB nuclear translocation were markedly inhibited and apoptosis attenuated in cells treated with ATOR. These effects occurred through inactivation of GSK-3β and subsequent activation of PP2Ac. They were abolished by treatment of cells with OA or PP2Ac siRNA. In mice with type 1 diabetes mellitus, treatment with ATOR, at 10 mg-kg⁻¹-d⁻¹, significantly suppressed GSK-3β activation, IKK/IкBα phosphorylation, NF-кB nuclear translocation and caspase-3 activation, while also activating PP2Ac. Finally, improvements in histological abnormalities, fibrosis, apoptosis and cardiac dysfunction were observed in diabetic mice treated with ATOR. These findings demonstrated that ATOR protected against HG-induced apoptosis in cardiomyocytes and alleviated experimental DCM by regulating the GSK-3β-PP2A-NF-κB signaling pathway.

Atorvastatin alleviates cardiomyocyte apoptosis by suppressing TRB3 induced by acute myocardial infarction and hypoxia

BACKGROUND/PURPOSE

TRB3 (tribbles 3), an apoptosis-regulated gene, increases during endoplasmic reticulum stress. Hypoxia can induce inflammatory mediators and apoptosis in cardiomyocytes. However, the expression of TRB3 in cardiomyocyte apoptosis under hypoxia is not thoroughly known. We investigated the regulation mechanism of TRB3 expression and apoptosis induced by hypoxia in cardiomyocytes.

METHODS

An in vivo model of acute myocardial infarction (AMI) was applied in adult Wistar rats to induce myocardial hypoxia. Rat neonatal cardiomyocytes were subjected to 2.5% O₂ to induce hypoxia.

RESULTS

The expression of TRB3 was evaluated in cultured rat neonatal cardiomyocytes subjected to hypoxia. Hypoxia significantly enhanced TRB3 protein and mRNA expression. Adding c-jun N-terminal kinase (JNK) inhibitor SP600125, JNK small interfering RNA (siRNA), tumor necrosis factor-α (TNF-α) antibody, and atorvastatin 30 minutes before hypoxia reversed the induction of TRB3 protein. A gel-shift assay showed the DNA-binding activity of growth arrest and DNA damage-inducible gene 153 (GADD153), which increased after hypoxia. Hypoxia increased, whereas the TRB3-mut plasmid, SP600125, and TNF-α antibody abolished the hypoxia-induced TRB3 promoter activity. Hypoxia increased the secretion of TNF-α from cardiomyocytes. Exogenous administration of TNF-α recombinant protein to the cardiomyocytes without hypoxia increased TRB3 protein expression, similar to that observed after hypoxia. Hypoxia-induced cardiomyocyte apoptosis is inhibited by TRB3 siRNA, the TNF-α antibody, and atorvastatin. Atorvastatin reduced the TRB3 expression and cardiomyocyte apoptosis induced by AMI. Hypoxia induces TRB3 through TNF-α, JNK, and the GADD153 pathway.

CONCLUSION

Treatment of atorvastatin inhibits the expression of TRB3 and cardiomyocyte apoptosis induced by AMI and hypoxia.

The antioxidant edaravone prevents cardiac dysfunction by suppressing oxidative stress in type 1 diabetic rats and in high-glucose-induced injured H9c2 cardiomyoblasts

Edaravone, a radical scavenger, has been recognized as a potential protective agent for cardiovascular diseases. However, little is known about the effect of edaravone in cardiac complications associated with diabetes. Here, we have demonstrated that edaravone prevents cardiac dysfunction and apoptosis in the streptozotocin-induced type 1 diabetic rat heart. Mechanistic studies revealed that edaravone treatment improved cardiac function and restored superoxide dismutase levels. In addition, treatment of diabetic animals by edaravone increased protein expressions of sirtuin-1 (SIRT-1), peroxisome proliferator activated receptor γ coactivator α (PGC-1α), nuclear factor like-2 (NRF-2), and B cell lymphoma 2 (Bcl-2), and reduced protein expressions of Bax and Caspase-3 compared to the control group. High glucose incubation resulted in the production of reactive oxygen species (ROS) and cell death. Treatment of high-glucose-incubated H9c2 cells by edaravone reduced ROS production and cell death. In addition, the treatment of high-glucose-incubated H9c2 cells by edaravone increased the activity of antioxidative stress by increasing SIRT-1, PGC-1α, and NRF-2, and this treatment also reduced apoptosis by increasing Bcl-2 expression and reducing Bax and Caspase-3 expressions. Knockdown SIRT-1 with small interferer RNA abolished the effects of edaravone. Overall, our data demonstrated that edaravone may be an effective agent against the development of diabetic cardiomyopathy.