New insight for SS­31 in treating diabetic cardiomyopathy: Activation of mitoGPX4 and alleviation of mitochondria­dependent ferroptosis.

SS­31 is a mitochondria­targeting antioxidant that exhibits promising therapeutic potential for various diseases; however, its protective effect on diabetic cardiomyopathy (DCM) remains to be elucidated. At present, SS­31 is considered not only to mitigate cardiolipin oxidative damage, but also to alleviate ferroptosis. The present study aimed to explore SS­31 as a potential therapeutic strategy for improving DCM by alleviating mitochondria­dependent ferroptosis. In vitro, H9C2 cells were exposed to 35 mM glucose for 24 h to induce high glucose damage, then were simultaneously treated with 10, 20 or 50 µM SS­31. In addition, in vivo studies were conducted on diabeticC57BL/6J mice, which were induced to develop DCM over 4 weeks, followed by intraperitoneal injections with 2.5 mg/kg/day SS­31 for a further 4 weeks. The elevation of serum lactate dehydrogenase and creatine kinase isoenzymes, the reduction of fractional shortening and ejection fraction, the rupture of myocardial fibers and the deposition of collagen indicated the establishment of the DCM mouse model. The results of the present study indicated that SS­31 effectively alleviated these pathological changes and exhibited significant efficacy in ameliorating mitochondrial dysfunction, such as by promoting adenosine triphosphate generation, improving mitochondrial membrane potential and restoring the mitochondrial ultrastructure. Further experiments suggested that activation of the mitochondrial glutathione (mitoGSH)/mitochondrial glutathione peroxidase 4 (mitoGPX4) pathway and the elimination of mitochondrial ferrous ions may constitute the mechanisms by which SS­31 treats DCM. Therefore, the present study revealed that mitochondria­dependent ferroptosis could serve as a pathogenic mechanism of DCM and highlighted that the cardioprotective effects of SS­31 against DCM involves activation of the mitoGSH/mitoGPX4 pathway. Due to the safety profile and cardiac protective effects of SS­31, SS­31 was considered a promising strategy for treating DCM.

Sacubitril/valsartan improves diastolic left ventricular stiffness with increased titin phosphorylation via cGMP-PKG activation in diabetic mice.

Titin, a giant sarcomeric protein, regulates diastolic left ventricular (LV) passive stiffness as a molecular spring and could be a therapeutic target for diastolic dysfunction. Sacubitril/valsartan (Sac/Val), an angiotensin receptor neprilysin inhibitor, has been shown to benefit patients with heart failure with preserved ejection fraction. The effect of Sac/Val is thought to be due to the enhancement of the cGMP/PKG pathway via natriuretic peptide. In this study, the effects of Sac/Val on LV diastolic dysfunction are demonstrated in a mouse diabetic cardiomyopathy model focusing on titin phosphorylation. Sac/Val-treated diabetic mice showed a greater increase in myocardial levels of cGMP-PKG than Val-treated and control mice. Conductance catheter analysis showed a significant reduction in LV stiffness in diabetic mice, but not in non-diabetic mice. Notably, diastolic LV stiffness was significantly reduced in Sac/Val-treated diabetic hearts compared with Val-treated or vehicle-treated diabetic mice. The phosphorylation level of titin (N2B), which determines passive stiffness and modulates active contraction, was higher in Sac/Val-treated hearts compared with Val-treated hearts in diabetic mice. Given that alteration of titin phosphorylation through PKG contributes to myocardial stiffness, the beneficial effects of Sac/Val in heart failure might be partly attributed to the induction of titin phosphorylation.

Cardiometabolic benefits of fenofibrate in heart failure related to obesity and diabetes.

BACKGROUND: Heart failure (HF) is a serious and common condition affecting millions of people worldwide, with obesity being a major cause of metabolic disorders such as diabetes and cardiovascular disease. This study aimed to investigate the effects of fenofibrate, a peroxisome proliferator-activated receptor alpha (PPARα) agonist, on the obese- and diabetes-related cardiomyopathy. METHODS AND RESULTS: We used db/db mice and high fat diet-streptozotocin induced diabetic mice to investigate the underlying mechanisms of fenofibrate's beneficial effects on heart function. Fenofibrate reduced fibrosis, and lipid accumulation, and suppressed inflammatory and immunological responses in the heart via TNF signaling. In addition, we investigated the beneficial effects of fenofibrate on HF hospitalization. The Korean National Health Insurance database was used to identify 427,154 fenofibrate users and 427,154 non-users for comparison. During the 4.22-year follow-up, fenofibrate use significantly reduced the risk of HF hospitalization (hazard ratio, 0.907; 95% CI 0.824-0.998). CONCLUSIONS: The findings suggest that fenofibrate may be a useful therapeutic agent for obesity- and diabetes-related cardiomyopathy.

Melatonin alleviates high glucose-induced cardiomyocyte injury through suppressing mitochondrial FUNDC1-DRP1 axis.

OBJECTIVES: To use H9c2 cardiomyocytes to establish a diabetic cardiomyopathic model by exposing these cells to high glucose (HG), followed by treating them with melatonin (MEL) or plasmid vectors overexpressing FUN14 Domain Containing 1 (FUNDC1). METHODS: We employed quantitative real-time PCR, mitochondrial staining, and biochemical assays to measure the activity of various antioxidant and mitochondrial complex functions under various treatment conditions. KEY FINDINGS: Our results showed that HG induced the expression of FUNDC1 and increased mitochondrial oxidative stress and fragmentation, while MEL treatment reversed most of these pathological effects. Moreover, HG exposure activated dynamin-related protein 1 expression and its translocation to mitochondria. Modulation of AMP-activated protein kinase level was found to be another pathological hallmark. In silico molecular docking, analysis revealed that MEL could directly bind the catalytic groove of FUNDC1 through Van der Waal's force and hydrogen bonding. Finally, MEL ameliorated diabetic cardiomyopathy-induced mitochondrial injury through FUNDC1 in vivo. CONCLUSIONS: Hyperglycemia induced mitochondrial fragmentation and altered electron transport chain complex functions, which could be ameliorated by MEL treatment, suggesting its potential as a cardiovascular therapeutic.

Modulating mitochondrial dynamics ameliorates left ventricular dysfunction by suppressing diverse cell death pathways after diabetic cardiomyopathy.

Diabetic cardiomyopathy (DCM) triggers a detrimental shift in mitochondrial dynamics, characterized by increased fission and decreased fusion, contributing to cardiomyocyte apoptosis and cardiac dysfunction. This study investigated the impact of modulating mitochondrial dynamics on DCM outcomes and underlying mechanisms in a mouse model. DCM induction led to upregulation of fission genes (Drp1, Mff, Fis1) and downregulation of fusion genes (Mfn1, Mfn2, Opa1). Inhibiting fission with Mdivi-1 or promoting fusion with Ginsenoside Rg1 preserved cardiac function, as evidenced by improved left ventricular ejection fraction (LVEF), fractional shortening (FS), and E/A ratio. Both treatments also reduced infarct size and attenuated cardiomyocyte apoptosis, indicated by decreased caspase-3 activity. Mechanistically, Mdivi-1 enhanced mitochondrial function by improving mitochondrial membrane potential, reducing reactive oxygen species (ROS) production, and increasing ATP generation. Ginsenoside Rg1 also preserved mitochondrial integrity and function under hypoxic conditions in HL-1 cardiomyocytes. These findings suggest that restoring the balance of mitochondrial dynamics through pharmacological interventions targeting either fission or fusion may offer a promising therapeutic strategy for mitigating MI-induced cardiac injury and improving patient outcomes.

Growth differentiation factor 15 alleviates diastolic dysfunction in mice with experimental diabetic cardiomyopathy.

Growth differentiation factor 15 (GDF15) is a peptide with utility in obesity, as it decreases appetite and promotes weight loss. Because obesity increases the risk for type 2 diabetes (T2D) and cardiovascular disease, it is imperative to understand the cardiovascular actions of GDF15, especially since elevated GDF15 levels are an established biomarker for heart failure. As weight loss should be encouraged in the early stages of obesity-related prediabetes/T2D, where diabetic cardiomyopathy is often present, we assessed whether treatment with GDF15 influences its pathology. We observed that GDF15 treatment alleviates diastolic dysfunction in mice with T2D independent of weight loss. This cardioprotection was associated with a reduction in cardiac inflammation, which was likely mediated via indirect actions, as direct treatment of adult mouse cardiomyocytes and differentiated THP-1 human macrophages with GDF15 failed to alleviate lipopolysaccharide-induced inflammation. Therapeutic manipulation of GDF15 action may thus have utility for both obesity and diabetic cardiomyopathy.

Active Ingredients and Mechanism of Gegen Qinlian Decoction in the Treatment of Diabetic Cardiomyopathy: A Network Pharmacology Study.

BACKGROUND: Diabetic cardiomyopathy (DCM) is a common diabetes complication with limited medications. Gegen Qinlian decoction (GQD) has been used in the treatment of diabetes and its related complications in China for several decades. OBJECTIVE: In this study, network pharmacology was employed to predict the active ingredients, key targets, and pathways involved in the treatment of DCM by GQD and to validate it by animal experiments. METHODS: The active ingredients of GQD were retrieved from TCMSP and published literature. DCM-related gene targets were searched in Drugbank, Genecards, Disgenet, and OMIM disease databases. Protein-protein interaction networks were constructed using the STRING database and Cytoscape. GO analysis and KEGG pathway enrichment analysis were performed using the Metascape platform. Moreover, a diabetic mouse model was established to evaluate the therapeutic effects of GQD by measuring serum biochemical markers and inflammation levels. Finally, the expression of predicted key target genes was determined using real-time quantitative PCR. RESULTS: A total of 129 active ingredients were screened from GQD. Moreover, 146 intersecting genes related to DCM were obtained, with key targets, including AKT1, TNF, IL6, and VEGFA. Lipid and atherosclerosis, AGE-RAGE, PI3K-AKT, and MAPK pathways were identified. Blood glucose control, decreased inflammatory factors, and serum CK-MB levels were restored after GQD intervention, and the same occurred with the expressions of PPAR-γ, AKT1, APOB, and GSK3B genes. CONCLUSION: Quercetin, kaempferol, wogonin, 7-methoxy-2-methyl isoflavone, and formononetin may exert major therapeutic effects by regulating key factors, such as AKT1, APOB, and GSK3B, in the inflammatory reaction, glycolipid oxidation, and glycogen synthesis related signaling pathways.

Forkhead box O1 transcription factor; a therapeutic target for diabetic cardiomyopathy.

Cardiovascular disease including diabetic cardiomyopathy (DbCM) represents the leading cause of death in people with diabetes. DbCM is defined as ventricular dysfunction in the absence of underlying vascular diseases and/or hypertension. The known molecular mediators of DbCM are multifactorial, including but not limited to insulin resistance, altered energy metabolism, lipotoxicity, endothelial dysfunction, oxidative stress, apoptosis, and autophagy. FoxO1, a prominent member of forkhead box O transcription factors, is involved in regulating various cellular processes in different tissues. Altered FoxO1 expression and activity have been associated with cardiovascular diseases in diabetic subjects. Herein we provide an overview of the role of FoxO1 in various molecular mediators related to DbCM, such as altered energy metabolism, lipotoxicity, oxidative stress, and cell death. Furthermore, we provide valuable insights into its therapeutic potential by targeting these perturbations to alleviate cardiomyopathy in settings of type 1 and type 2 diabetes.

Role of melatonin in mitigation of insulin resistance and ensuing diabetic cardiomyopathy.

Addressing insulin resistance or hyperinsulinemia might offer a viable treatment approach to stop the onset of diabetic cardiomyopathy, as these conditions independently predispose to the development of the disease, which is initially characterized by diastolic abnormalities. The development of diabetic cardiomyopathy appears to be driven mainly by insulin resistance or impaired insulin signalling and/or hyperinsulinemia. Oxidative stress, hypertrophy, fibrosis, cardiac diastolic dysfunction, and, ultimately, systolic heart failure are the outcomes of these pathophysiological alterations. Melatonin is a ubiquitous indoleamine, a widely distributed compound secreted mainly by the pineal gland, and serves a variety of purposes in almost every living creature. Melatonin is found to play a leading role by improving myocardial cell metabolism, decreasing vascular endothelial cell death, reversing micro-circulation disorders, reducing myocardial fibrosis, decreasing oxidative and endoplasmic reticulum stress, regulating cell autophagy and apoptosis, and enhancing mitochondrial function. This review highlights a relationship between insulin resistance and associated cardiomyopathy. It explores the potential therapeutic strategies offered by the neurohormone melatonin, an important antioxidant that plays a leading role in maintaining glucose homeostasis by influencing the glucose transporters independently and through its receptors. The vast distribution of melatonin receptors in the body, including beta cells of pancreatic islets, asserts the role of this indole molecule in maintaining glucose homeostasis. Melatonin controls the production of GLUT4 and/or the phosphorylation process of the receptor for insulin and its intracellular substrates, activating the insulin-signalling pathway through its G-protein-coupled membrane receptors.

[Research progress of traditional Chinese medicine in regulating autophagy for intervening in diabetic cardiomyopathy].

Diabetic cardiomyopathy(DCM) is a chronic complication of diabetes mellitus that leads to cardiac damage in the later stages of the disease, and its pathogenesis is complex, involving metabolic disorders brought about by a variety of aberrant alterations such as endoplasmic reticulum stress, oxidative stress, inflammation, and apoptosis, defects in cardiomyocyte Ca~(2+) transporter, and myocardial fibrosis. Currently, there is a lack of specific diagnosis and treatment in the clinic. Autophagy is a highly conserved scavenging mechanism that removes proteins, damaged organelles or foreign contaminants and converts them into energy and amino acids to maintain the stability of the intracellular environment. Inhibition of autophagy can cause harmful metabolites to accumulate in the cell, while over-activation of autophagy can disrupt normal cellular structures and cause cell death. Prolonged high glucose levels disrupt cardiomyocyte autophagy levels and exacerbate the development of DCM. The protective or detrimental effects of autophagy on cells ring true with the traditional Chinese medicine theory of healthy Qi and pathogenic Qi. Autophagy in the physiological state of the removal of intracellular substances and the generation of substances beneficial to the survival of cells is the inhibition of pathogenic Qi to help the performance of healthy Qi, so the organism is healthy. In the early stages of the disease, when autophagy is impaired and incapable of removing waste substances, pathogenic Qi is prevalent; In the later stages of the disease, excessive activation of autophagy can destroy normal cells, leading to a weakening of healthy Qi. Traditional Chinese medicine has the advantage of targeting multiple sites and pathways. Studies in recent years have confirmed that traditional Chinese medicine monomers or formulas can target autophagy, promote the restoration of autophagy levels, maintain mitochondrial and endoplasmic reticulum homeostasis, and reduce oxidative stress, endoplasmic reticulum stress, inflammation, and apoptosis in order to prevent and control DCM. This study provides a review of the relationship between autophagy and DCM and the intervention of traditional Chinese medicine in autophagy for the treatment of DCM, with a view to providing new clinical ideas and methods for the treatment of DCM with traditional Chinese medicine.

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

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

Ginsenoside Rb1 reduces oxidative/carbonyl stress damage and dysfunction of RyR2 in the heart of streptozotocin-induced diabetic rats.

BACKGROUND: Oxidative stress may contribute to cardiac ryanodine receptor (RyR2) dysfunction in diabetic cardiomyopathy. Ginsenoside Rb1 (Rb1) is a major pharmacologically active component of ginseng to treat cardiovascular diseases. Whether Rb1 treat diabetes injured heart remains unknown. This study was to investigate the effect of Rb1 on diabetes injured cardiac muscle tissue and to further investigate its possible molecular pharmacology mechanisms. METHODS: Male Sprague-Dawley rats were injected streptozotocin solution for 2 weeks, followed 6 weeks Rb1 or insulin treatment. The activity of SOD, CAT, Gpx, and the levels of MDA was measured; histological and ultrastructure analyses, RyR2 activity and phosphorylated RyR2(Ser2808) protein expression analyses; and Tunel assay were performed. RESULTS: There was decreased activity of SOD, CAT, Gpx and increased levels of MDA in the diabetic group from control. Rb1 treatment increased activity of SOD, CAT, Gpx and decreased the levels of MDA as compared with diabetic rats. Neutralizing the RyR2 activity significantly decreased in diabetes from control, and increased in Rb1 treatment group from diabetic group. The expression of phosphorylation of RyR2 Ser2808 was increased in diabetic rats from control, and were attenuated with insulin and Rb1 treatment. Diabetes increased the apoptosis rate, and Rb1 treatment decreased the apoptosis rate. Rb1 and insulin ameliorated myocardial injury in diabetic rats. CONCLUSIONS: These data indicate that Rb1 could be useful for mitigating oxidative damage, reduced phosphorylation of RyR2 Ser2808 and decreased the apoptosis rate of cardiomyocytes in diabetic cardiomyopathy.

The investigation of potential mechanism of Fuzhengkangfu Decoction against Diabetic myocardial injury based on a combined strategy of network pharmacology, transcriptomics, and experimental verification.

BACKGROUND AND OBJECTIVES: Diabetic cardiomyopathy (DCM) is a cardiac condition resulting from myocardial damage caused by diabetes mellitus (DM), currently lacking specific therapeutic interventions. Fuzhengkangfu decoction (FZK) plays an important role in the prevention and treatment of various cardiovascular diseases. However, the efficacy and potential mechanisms of FZK are not fully understood. This study aims to investigate the protective effect and mechanisms of FZK against DCM. METHODOLOGIES: Rats were given a high-calorie diet along with a low dosage of streptozotocin (STZ) to establish a rat model of DCM. The diabetic rats received FZK or normal saline subcutaneously for 12 weeks. Echocardiography was conducted to evaluate their heart function characteristics. Rat heart morphologies were assessed using Sirius Red staining and H&E staining. Transcriptome sequencing analysis and network pharmacology were used to reveal possible targets and mechanisms. Molecular docking was conducted to validate the association between the primary components of FZK and the essential target molecules. Finally, both in vitro and in vivo studies were conducted on the cardioprotective properties and mechanism of FZK. RESULTS: According to the results of network pharmacology, FZK may prevent DCM by reducing oxidative stress and preventing apoptosis. Transcriptomics confirmed that FZK protected against DCM-induced myocardial fibrosis and remodelling, as predicted by network pharmacology, and suggested that FZK regulated the expression of oxidative stress and apoptosis-related proteins. Integrating network pharmacology and transcriptome analysis results revealed that the AGE-RAGE signalling pathway-associated MMP2, SLC2A1, NOX4, CCND1, and CYP1A1 might be key targets. Molecular docking showed that Poricoic acid A and 5-O-Methylvisammioside had the highest docking activities with these targets. We further conducted in vivo experiments, and the results showed that FZK significantly attenuated left ventricular remodelling, reduced myocardial fibrosis, and improved cardiac contractile function. And, our study demonstrated that FZK effectively reduced oxidative stress and apoptosis of cardiomyocytes. The data showed that Erk, NF-κB, and Caspase 3 phosphorylation was significantly inhibited, and Bcl-2/Bax was significantly increased after FZK treatment. In vitro, FZK significantly reduced AGEs-induced ROS increase and apoptosis in cardiomyocytes. Furthermore, FZK significantly inhibited the phosphorylation of Erk and NF-κB proteins and decreased the expression of MMP2. All the results confirmed that FZK inhibited the activation of the Erk/NF-κB pathway in AGE-RAGE signalling and alleviated oxidative stress and apoptosis of cardiomyocytes. In summary, we verified that FZK protects against DCM by inhibiting myocardial apoptotic remodelling through the suppression of the AGE-RAGE signalling pathway. CONCLUSION: In conclusion, our research indicates that FZK demonstrates anti-cardiac dysfunction properties by reducing oxidative stress and cardiomyocyte apoptosis through the AGE-RAGE pathway in DCM, showing potential for therapeutic use.

Cannabinoid 2 Receptor Activation Protects against Diabetic Cardiomyopathy through Inhibition of AGE/RAGE-Induced Oxidative Stress, Fibrosis, and Inflammasome Activation.

Oxidative stress, fibrosis, and inflammasome activation from advanced glycation end product (AGE)-receptor of advanced glycation end product (RAGE) interaction contribute to diabetic cardiomyopathy (DCM) formation and progression. Our study revealed the impact of ß-caryophyllene (BCP) on activating cannabinoid type 2 receptors (CB2Rs) against diabetic complication, mainly cardiomyopathy and investigated the underlying cell signaling pathways in mice. The murine model of DCM was developed by feeding a high-fat diet with streptozotocin injections. After the development of diabetes, the animals received a 12-week oral BCP treatment at a dose of 50 mg/kg/body weight. BCP treatment showed significant improvement in glucose tolerance and insulin resistance and enhanced serum insulin levels in diabetic animals. BCP treatment effectively reversed the heart remodeling and restored the phosphorylated troponin I and sarcoplasmic/endoplasmic reticulum Ca2+ ATPase 2a expression. Ultrastructural examination showed reduced myocardial cell injury in DCM mice treated with BCP. The preserved myocytes were found to be associated with reduced expression of AGE/RAGE in DCM mice hearts. BCP treatment mitigated oxidative stress by inhibiting expression of NADPH oxidase 4 and activating phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/nuclear factor erythroid 2-related factor 2 (Nrf2) signaling. Also, BCP suppressed cardiac fibrosis and endothelial-to-mesenchymal transition in DCM mice by inhibiting transforming growth factor ß (TGF-ß)/suppressor of mothers against decapentaplegic (Smad) signaling. Further, BCP treatment suppressed nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3) inflammasome activation in DCM mice and alleviated cellular injury to the pancreatic tissues evidenced by significant elevation of the number of insulin-positive cells. To demonstrate a CB2R-dependent mechanism of BCP, another group of DCM mice were pretreated with AM630, a CB2R antagonist. AM630 was observed to abrogate the beneficial effects of BCP in DCM mice. Taken together, BCP demonstrated the potential to protect the myocardium and pancreas of DCM mice mediating CB2R-dependent mechanisms. SIGNIFICANCE STATEMENT: BCP, a CB2R agonist, shows protection against DCM. BCP attenuates oxidative stress, inflammation, and fibrosis in DCM via activating CB2Rs. BCP mediating CB2R activation favorably modulates AGE/RAGE, PI3K/AKT/Nrf2ß and TGF-ß/Smad and (NLRP3) inflammasome in diabetic cardiomyopathy.

Nimbolide protects against diabetic cardiomyopathy by regulating endoplasmic reticulum stress and mitochondrial function via the Akt/mTOR pathway.

Nimbolide has been demonstrated to possess protective properties against gestational diabetes mellitus and diabetic retinopathy. However, the role and molecular mechanism of nimbolide in diabetic cardiomyopathy (DCM) remain unknown. Diabetes was induced in rats via a single injection of streptozotocin (STZ) and then the diabetic rats were administered nimbolide (5 mg/kg and 20 mg/kg) or dimethyl sulfoxide daily for 12 weeks. H9c2 cardiomyocytes were exposed to high glucose (25 mM glucose) to mimic DCM in vitro. The protective effects of nimbolide against DCM were evaluated in vivo and in vitro. The potential molecular mechanism of nimbolide in DCM was further explored. We found that nimbolide dose-dependently decreased blood glucose and improved body weight of diabetic rats. Additionally, nimbolide dose-dependently improved cardiac function, alleviated myocardial injury/fibrosis, and inhibited endoplasmic reticulum (ER) stress and apoptosis in diabetic rats. Moreover, nimbolide dose-dependently improved mitochondrial function and activated the Akt/mTOR signaling. We consistently demonstrated the cardioprotective effects of nimbolide in an in vitro model of DCM. The involvement of ER stress and mitochondrial pathways were further confirmed by using inhibitors of ER stress and mitochondrial division. By applying a specific Akt inhibitor SC66, the cardioprotective effects of nimbolide were partially blocked. Our study indicated that nimbolide alleviated DCM by activating Akt/mTOR pathway. Nimbolide may be a novel therapeutic agent for DCM treatment.

Therapeutic effect of Momordica charantia on cardiomyopathy in a diabetic maternal rat model.

Myocardial structural and functional abnormalities are hallmarks of diabetic cardiomyopathy (DCM), a chronic consequence of diabetes mellitus (DM). Maternal DM affects and increases the risk of heart defects in diabetic mothers compared with nondiabetic mothers. Momordica charantia exhibits antidiabetic effects due to various bioactive compounds that are phytochemicals, a broad group that includes phenolic compounds, alkaloids, proteins, steroids, inorganic compounds, and lipids. Pregnant maternal rats were split into four groups: control (C), M. charantia-treated (MC), type 2 diabetes mellitus (T2DM) (DM), and diabetic (MC + DM) groups. Diabetes mothers had increased serum glucose, insulin, total cholesterol, triglyceride, and low-density lipoprotein cholesterol levels and reduced high-density lipoprotein cholesterol levels. Cardiac biomarkers such as cardiac troponin T (cTnT), creatine kinase-myocardial band (CK-MB), and lactate dehydrogenase were increased. Hormone levels of follicle-stimulating hormone, luteinizing hormone, progesterone, and estrogen decreased significantly. Inflammatory markers such as interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-α), and vascular adhesion molecule-1 (VCAM-1) were elevated in diabetic mothers. Oxidative stress markers indicated increased malondialdehyde and nitric oxide levels, while antioxidants such as glutathione, superoxide dismutase, and catalase were decreased in maternal heart tissue. The levels of apoptotic markers such as tumor suppressor 53 (P53) and cysteine aspartic protease-3 (caspase-3) were significantly greater in diabetic maternal heart tissue. Histopathological analysis revealed heart tissue abnormalities in diabetic maternal rats. M. charantia extract improved maternal diabetes-induced changes in inflammation, antioxidant levels, and heart tissue structure.

[Compound Yuye Decoction protects diabetic rats against cardiomyopathy by inhibiting myocardial apoptosis and inflammation via regulating the PI3K/Akt signaling pathway].

OBJECTIVE: To explore the therapeutic mechanism of compound Yuye Decoction against diabetic cardiomyopathy (DCM). METHODS: Drugbank, Gene Cards, OMIM and PharmGKb databases were used to obtain DCM-related targets, and the core targets were identified and functionally annotated by protein-protein interaction network analysis followed by GO and KEGG enrichment analysis. The "Traditional Chinese Medicine-Key Component-Key Target-Key Pathway" network was constructed using Cytoscape 3.9.1, and molecular docking was carried out for the key components and the core targets. In the animal experiment, Wistar rat models of DCM were treated with normal saline or Yuye Decoction by gavage at low (0.29 g/kg) and high (1.15 g/kg) doses for 8 weeks, and the changes in cardiac electrophysiology and histopathology were evaluated. The changes in serum levels of LDH, CK, and CK-MB were examined, and myocardial expressions of PI3K, P-PI3K, Akt, P-AKT, BAX, IL-6, and TNF-α were detected using Western blotting. RESULTS: We identified 61 active compounds in Yuye Decoction with 1057 targets, 3682 DCM-related disease targets, and 551 common targets between them. Enrichment of the core targets suggested that apoptosis, inflammation and the PI3K/Akt pathways were the key signaling pathways for DCM treatment. Molecular docking studies showed that the active components in Yuye Decoction including gold amidohydroxyethyl ester and kaempferol had strong binding activities with AKT1 and PIK3R1. In DCM rat models, treatment with Yuye Decoction significantly alleviated myocardial pathologies, reduced serum levels of LDH, CK and CK-MB, lowered myocardial expressions of BAX, IL-6 and TNF-α, and increased the expressions of P-PI3K and P-AKT. CONCLUSION: The therapeutic effect of compound Yuye Decoction against DCM is mediated by its multiple active components that act on multiple targets and pathways to inhibit cardiomyocyte apoptosis and inflammatory response by regulating the PI3K/Akt signaling pathway.

Cardioprotective Effects of 'Vasant Kusumakar Rasa,' a Herbo-metallic Formulation, in Type 2 Diabetic Cardiomyopathy in Rats.

Diabetic cardiomyopathy (DCM) is one of the serious complications of type 2 diabetes mellitus. Vasant Kusumakar Rasa (VKR) is a Herbo-metallic formulation reported in Ayurveda, an Indian system of medicine. The present work was designed to study the effect of VKR in cardiomyopathy in type 2 diabetic rats. Diabetes was induced by feeding a high-fat diet (HFD) for 2 weeks followed by streptozotocin (STZ) administration (35 mg/kg i.p.). VKR was administered orally at dose of 28 and 56 mg/kg once a day for 16 weeks. The results of the study indicated that VKR treatment significantly improved the glycemic and lipid profile, serum insulin, CK-MB, LDH, and cardiac troponin-I when compared to diabetic control animals. VKR treatment in rats significantly improved the hemodynamic parameters and cardiac tissue levels of TNF-α, IL-1ß, and IL- 6 were also reduced. Antioxidant enzymes such as GSH, SOD, and catalase were improved in all treatment groups. Heart sections stained with H & E and Masson's trichome showed decreased damage to histoarchitecture of the myocardium. Expression of PI3K, Akt, and GLUT4 in the myocardium was upregulated after 16 weeks of VKR treatment. The study data suggested the cardioprotective capability of VKR in the management of diabetic cardiomyopathy in rats.