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

Ferroptosis Is a Potential Novel Diagnostic and Therapeutic Target for Patients With Cardiomyopathy

Cardiomyocyte death is a fundamental progress in cardiomyopathy. However, the mechanism of triggering the death of myocardial cells remains unclear. Ferroptosis, which is the nonapoptotic, iron-dependent, and peroxidation-driven programmed cell death pathway, that is abundant and readily accessible, was not discovered until recently with a pharmacological approach. New researches have demonstrated the close relationship between ferroptosis and the development of many cardiovascular diseases, and several ferroptosis inhibitors, iron chelators, and small antioxidant molecules can relieve myocardial injury by blocking the ferroptosis pathways. Notably, ferroptosis is gradually being considered as an important cell death mechanism in the animal models with multiple cardiomyopathies. In this review, we will discuss the mechanism of ferroptosis and the important role of ferroptosis in cardiomyopathy with a special emphasis on the value of ferroptosis as a potential novel diagnostic and therapeutic target for patients suffering from cardiomyopathy in the future.

Concurrent diabetes and heart failure: interplay and novel therapeutic approaches

Diabetes mellitus increases the risk of developing heart failure, and the co-existence of both diseases worsens cardiovascular outcomes, hospitalization and the progression of heart failure. Despite current advancements on therapeutic strategies to manage hyperglycemia, the likelihood of developing diabetes-induced heart failure is still significant, especially with the accelerating global prevalence of diabetes and an ageing population. This raises the likelihood of other contributing mechanisms beyond hyperglycemia in predisposing diabetic patients to cardiovascular disease risk. There has been considerable interest in understanding the alterations in cardiac structure and function in the diabetic patients, collectively termed as "diabetic cardiomyopathy". However, the factors that contribute to the development of diabetic cardiomyopathies is not fully understood. This review summarizes the main characteristics of diabetic cardiomyopathies, and the basic mechanisms that contribute to its occurrence. This includes perturbations in insulin resistance, fuel preference, reactive oxygen species generation, inflammation, cell death pathways, neurohormonal mechanisms, advanced glycated end-products accumulation, lipotoxicity, glucotoxicity, and posttranslational modifications in the heart of the diabetic. This review also discusses the impact of antihyperglycemic therapies on the development of heart failure, as well as how current heart failure therapies influence glycemic control in diabetic patients. We also highlight the current knowledge gaps in understanding how diabetes induces heart failure.

Rosmarinic acid ameliorated cardiac dysfunction and mitochondrial injury in diabetic cardiomyopathy mice via activation of the SIRT1/PGC-1α pathway

Mitochondrial injury plays an essential role in the pathogenesis of diabetic cardiomyopathy (DCM). Previous studies demonstrated that rosmarinic acid (RA) treatment prevented high glucose-induced mitochondrial injury in vitro. However, whether RA can ameliorate cardiac function by preventing mitochondrial injury in DCM is unknown. The SIRT1/PGC-1α pathway has emerged as an important regulator of metabolic control and other mitochondrial functions. The present study was undertaken to determine the effects of RA on mitochondrial and cardiac function in DCM as well as the involvement of the SIRT1/PGC-1α pathway. Our results revealed that RA improved cardiac systolic and diastolic function and prevented mitochondrial injury in DCM, as shown by the reduced blood glucose and lipid levels, increased mitochondrial membrane potential levels, improved adenosine triphosphate synthesis, and inhibited apoptosis (P < 0.05). Moreover, RA upregulated the expression of SIRT1 and PGC-1α in DCM mice and high glucose-treated H9c2 cardiomyocytes (P < 0.05). Further mechanistic studies in H9c2 cardiomyocytes revealed that suppression of SIRT1 by Sh-SIRT1 counteracted the effects of RA on high glucose-induced abnormal metabolism of glucose and lipids, oxidative stress and apoptosis (P < 0.05). Taken together, these data indicate that RA prevented mitochondrial injury and cardiac dysfunction in DCM mice, and the SIRT1/PGC-1α pathway mediated the protective effects of RA.

Adiponectin Modified BMSCs Alleviate Heart Fibrosis via Inhibition TGF-beta1/Smad in Diabetic Rats

Background: Accumulating evidence suggested that bone marrow mesenchymal stem cells (BMSCs) have therapeutic potential for diabetes and heart diseases. However, the effects of BMSC on reducing myocardial fibrosis need to be optimized. This study aimed to investigate the mechanism of adiponectin (APN) modified BMSCs on myocardial fibrosis in diabetic model in vivo and in vitro.

Methods: The high-fat diet combined with streptozotocin (STZ) injection were used to induced diabetic rat model. H9c2 cells were cultured under a high glucose medium as in vitro model. The BMSCs were modified by APN plasmid or APN small interfering RNA (siRNA), then transplanted to the diabetic rats by a single tail-vein injection, or co-cultured with H9c2 cells.

Results: We demonstrated that diabetic rats showed typical diabetic symptoms, such as decreased cardiac function, accumulation of pathological lesions and collagen expression. However, these impairments were significantly prevented by the APN modified BMSCs treatment while no effects on APN siRNA modified BMSCs treated diabetic rats. Moreover, we confirmed that APN modified BMSCs could attenuate the expression of TGF-beta1/smad to suppress the myocardial fibrosis in the diabetic rats and high glucose induced H9c2 cells.

Conclusion: The present results for the first time showed that APN modified BMSCs exerted protection on cardiac fibrosis via inhibiting TGF-beta1/smad signal pathway in diabetic rats. Our findings suggested that APN modified BMSCs might be a novel and optimal therapy for the diabetic cardiomyopathy in future.

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.

The Role of the Interplay Between Autophagy and NLRP3 Inflammasome in Metabolic Disorders

Autophagy is an important and conserved cellular pathway in which cells transmit cytoplasmic contents to lysosomes for degradation. It plays an important role in maintaining the balance of cell composition synthesis, decomposition and reuse, and participates in a variety of physiological and pathological processes. The nucleotide-binding oligomerization domain-like receptor family, pyrin domain-containing 3 (NLRP3) inflammasome can induce the maturation and secretion of Interleukin-1 beta (IL-1β) and IL-18 by activating caspase-1. It is involved in many diseases. In recent years, the interplay between autophagy and NLRP3 inflammasome has been reported to contribute to many diseases including metabolic disorders related diseases. In this review, we summarized the recent studies on the interplay between autophagy and NLRP3 inflammasome in metabolic disorders to provide ideas for the relevant basic research in the future.

CircRNAs in diabetic cardiomyopathy

Diabetic cardiomyopathy is an important irreversible chronic cardiovascular complication in diabetic patients. This condition is described as early diastolic dysfunction, myocardial fibrosis, cardiac hypertrophy, systolic dysfunction and other complex pathophysiological events, which ultimately lead to heart failure. Despite these characteristics, the underlying mechanisms resulting in diabetic cardiomyopathy are still unknown. With the developments in molecular biotechnology, increasing evidence shows that circRNAs play critical roles in the pathogenesis of diabetic cardiomyopathy. The purpose of this review is to summarize recent studies on the role of circRNAs in the pathophysiological process to provide novel prevention and treatment strategies for diabetic cardiomyopathy, oxidative stress, inflammation, endothelial dysfunction, myocardial fibrosis and cell death in diabetic cardiomyopathy.

Aldosterone Induces Vasoconstriction in Individuals with Type 2 Diabetes: Effect of Acute Antioxidant Administration

CONTEXT

Individuals with type 2 diabetes have an increased risk of endothelial dysfunction and cardiovascular disease. Plasma aldosterone could contribute by reactive oxygen species-dependent mechanisms by inducing a shift in the balance between a vasoconstrictor and vasodilator response to aldosterone.

OBJECTIVE

We aimed to investigate the acute vascular effects of aldosterone in individuals with type 2 diabetes compared with healthy controls and if infusion of an antioxidant (n-acetylcysteine [NAC]) would alter the vascular response.

METHODS

In a case-control design, 12 participants with type 2 diabetes and 14 healthy controls, recruited from the general community, were studied. Leg hemodynamics were measured before and during aldosterone infusion (0.2 and 5 ng min-1 [L leg volume]-1) for 10 minutes into the femoral artery with and without coinfusion of NAC (125 mg kg-1 hour-1 followed by 25 mg kg-1 hour-1). Leg blood flow and arterial blood pressure was measured, and femoral arterial and venous blood samples were collected.

RESULTS

Compared with the control group, leg blood flow and vascular conductance decreased during infusion of aldosterone at the high dose in individuals with type 2 diabetes, whereas coinfusion of NAC attenuated this response. Plasma aldosterone increased in both groups during aldosterone infusion and there was no difference between groups at baseline or during the infusions.

CONCLUSION

These results suggests that type 2 diabetes is associated with a vasoconstrictor response to physiological levels of infused aldosterone and that the antioxidant NAC diminishes this response.

Calcium Dobesilate (CaD) Attenuates High Glucose and High Lipid-Induced Impairment of Sarcoplasmic Reticulum Calcium Handling in Cardiomyocytes

Calcium dobesilate (CaD) is used effectively in patients with diabetic microvascular disorder, retinopathy, and nephropathy. Here we sought to determine whether it has an effect on cardiomyocytes calcium mishandling that is characteristic of diabetic cardiomyopathy. Cardiomyocytes were sterile isolated and cultured from 1 to 3 days neonatal rats and treated with vehicle (Control), 25 mM glucose+300 μM Palmitic acid (HG+PA), 100 μM CaD (CaD), or HG+PA+CaD to test the effects on calcium signaling (Ca2+ sparks, transients, and SR loads) and reactive oxygen species (ROS) production by confocal imaging. Compared to Control, HG+PA treatment significantly reduced field stimulation-induced calcium transient amplitudes (2.22 ± 0.19 vs. 3.56 ± 0.21, p < 0.01) and the levels of caffeine-induced calcium transients (3.19 ± 0.14 vs. 3.72 ± 0.15, p < 0.01), however significantly increased spontaneous Ca2+ sparks firing levels in single cardiomyocytes (spontaneous frequency 2.65 ± 0.23 vs. 1.72 ± 0.12, p < 0.01) and ROS production (67.12 ± 4.4 vs. 47.65 ± 2.12, p < 0.05), which suggest that HG+PA treatment increases the Spontaneity Ca2+ spark frequency, and then induced partial reduction of SR Ca2+ content and subsequently weaken systolic Ca2+ transient in cardiomyocyte. Remarkably, these impairments in calcium signaling and ROS production were largely prevented by pre-treatment of the cells with CaD. Therefore, CaD may contribute to a good protective effect on patients with calcium mishandling and contractile dysfunction in cardiomyocytes associated with diabetic cardiomyopathy.

Protective effects of medicinal plant against diabetes induced cardiac disorder: A review

ETHNOPHARMACOLOGY RELEVANCE

Nowadays, there is an increase in global tendency to use medicinal plants as preventive and therapeutic agents to manage diabetes and its long-term complications such as cardiovascular disorders owing to their availability and valuable traditional background.

AIM OF STUDY

This review aims to introduce common medicinal plants, which have been demonstrated to have cardioprotective effects on diabetes and their mechanisms of action.

MATERIALS AND METHODS

Online literature databases, including Web of Sciences, PubMed, Science Direct, Scopus and Google Scholar were searched without date limitation by May 2020. The following keywords (natural products or medicinal plants or herbal medicine or herb or extract) and (diabetes or antidiabetic or hyperglycemic) and (cardiomyopathy or heart or cardioprotective or cardiac or cardio) were used, and after excluding non-relevant articles, 81 original English articles were selected.

RESULTS

The surveyed medicinal plants induced cardioprotective effects mostly through increasing antioxidant effects leading to attenuating ROS production as well as by inhibiting inflammatory signaling pathways and related cytokines. Moreover, they ameliorated the Na+/K + ATPase pump, the L-type Ca₂⁺ channel current, and the intracellular ATP. They also reduced cardiac remodeling and myocardial cell apoptosis through degradation of caspase-3, Bax, P53 protein, enhancement of Bcl-2 protein expression as well as downregulation of TGFβ1 and TNFα expression. In addition, the extracts improved cardiac function through increasing EF% and FS% as well as restoring hemodynamic parameters.

CONCLUSIONS

The reviewed medicinal plants demonstrated cardioprotective manifestations in diabetes through intervention with mechanisms involved in the diabetic heart to restore cardiovascular complications.

Escitalopram Ameliorates Cardiomyopathy in Type 2 Diabetic Rats via Modulation of Receptor for Advanced Glycation End Products and Its Downstream Signaling Cascades

Type 2 diabetes mellitus (T2DM) has been recognized as a known risk factor for cardiovascular diseases. Additionally, studies have shown the prevalence of depression among people with diabetes. Thus, the current study aimed to investigate the possible beneficial effects of escitalopram, a selective serotonin reuptake inhibitor, on metabolic changes and cardiac complications in type 2 diabetic rats. Diabetes was induced by feeding the rats high fat-high fructose diet (HFFD) for 8 weeks followed by a subdiabetogenic dose of streptozotocin (STZ) (35 mg/kg, i. p.). Treatment with escitalopram (10 mg/kg/day; p. o.) was then initiated for 4 weeks. At the end of the experiment, electrocardiography was performed and blood samples were collected for determination of glycemic and lipid profiles. Animals were then euthanized and heart samples were collected for biochemical and histopathological examinations. Escitalopram alleviated the HFFD/STZ-induced metabolic and cardiac derangements as evident by improvement of oxidative stress, inflammatory, fibrogenic and apoptotic markers in addition to hypertrophy and impaired conduction. These results could be secondary to its beneficial effects on the glycemic control and hence the reduction of receptor for advanced glycation end products content as revealed in the present study. In conclusion, escitalopram could be considered a favorable antidepressant medication in diabetic patients as it seems to positively impact the glycemic control in diabetes in addition to prevention of its associated cardiovascular complications.

Knowledge and Perceptions Towards Cardiovascular Disease Prevention Among Patients with Type 2 Diabetes Mellitus: A Review of Current Assessments and Recommendations

INTRODUCTION

Patients with type 2 diabetes mellitus (T2DM) are at significantly higher risk of developing cardiovascular diseases (CVD). There is a scarcity of literature reviews that describe and summarize T2DM patients' knowledge and perception about CVD prevention.

OBJECTIVES

To describe and summarize the assessment of knowledge and perceptions about CVD risk and preventive approaches among patients with T2DM.

METHODS

A scoping review methodology was adopted, and three scientific databases, Google Scholar, Science Direct, and PubMed were searched using predefined search terms. A multistage screening process that considered relevancy, publication year (2009-2019), English language, and article type (original research) was followed. We formulated research questions focused on the assessment of levels of knowledge and perceptions of the illness relevant to CVD prevention and the identification of associated patients' characteristics.

RESULTS

A total of 16 studies were included. Patients were not confident to identify CVD risk and other clinical consequences that may occur in the prognostic pathway of T2DM. Furthermore, patients were less likely to identify all CV risk factors indicating a lack of understanding of the multi-- factorial contribution of CVD risk. Patients' beliefs about medications were correlated with their level of adherence to medications for CVD prevention. Many knowledge gaps were identified, including the basic disease expectations at the time of diagnosis, identification of individuals' CVD risk factors, and management aspects. Knowledge and perceptions were affected by patients' demographic characteristics, e.g., educational level, race, age, and area of residence.

CONCLUSION

There are knowledge gaps concerning the understanding of CVD risk among patients with T2DM. The findings necessitate educational initiatives to boost CVD prevention among patients with T2DM. Furthermore, these should be individualized based on patients' characteristics, knowledge gaps, disease duration, and estimated CVD risk.

Fisetin protects against streptozotocin-induced diabetic cardiomyopathy in rats by suppressing fatty acid oxidation and inhibiting protein kinase R

This study examined if the Fisetin against streptozotocin-induced diabetic cardiomyopathy (DC) in rats involves regulating cardiac metabolism and suppressing protein kinase R (PKR). Male rats were divided (12/groups) as control (non-diabetic), control + Fisetin, T1DM, and T1DM + Fisetin. Fisetin was administered orally at a final dose of 2.5 mg/kg for 12 weeks. In T1DM1-induced rats, Fisetin prevented heart and final body weights loss, lowered circulatory levels troponin I and creatinine kinase-MB (CK-MB), increased fasting insulin levels, and improved ventricular systolic and diastolic functions. It also preserved the structure of the cardiomyocytes and reduced oxidative stress, fibrosis, protein levels of transforming growth factor-β1 (TGF-β1), collagenase 1A, caspase-3, and the activation of JNK, p53, and p38 MAPK. In the control and diabetic rats, Fisetin attenuated fasting hyperglycaemia, the increases in glucose levels after the oral and insulin tolerance tests, and HOMA-IR. It also increased cardiac glucose oxidation by increasing the activity of private dehydrogenase (PDH), phosphofructokinase (PFK), protein levels of PPAR-α and suppressed cardiac inflammation by inhibiting NF-κB. These effects were associated with a reduction in the activity of PKR and subsequent increase in the activity of eeukaryotic initiation factor 2 (eIF2) with a parallel increase in protein levels of p67, a cellular inhibitor of PKR. In cultured cardiomyocytes, Fisetin, prevented high glucose (HG)-induced activation of PKR and reduction in p67, in a dose-dependent manner. However, the effect of Fisetin on PKR was diminished in LG and HG-treated cardiomyocytes with p67-siRNA. In conclusion, Fisetin protects against DC in rats by improving cardiac glucose metabolism and suppressing PKR.

Temporal evolution of cardiac mitochondrial dysfunction in a type 1 diabetes model. Mitochondrial complex I impairment, and H2O2 and NO productions as early subcellular events

The aim of this work was to study the early events that occur in heart mitochondria and to analyse the temporal evolution of cardiac mitochondrial dysfunction in a type 1 diabetes model. Male Wistar rats were injected with Streptozotocin (STZ, single dose, 60 mg × kg^-1, i.p.) and hyperglycemic state was confirmed 72 h later. The animals were sacrificed 10 or 14 days after STZ-injection. Heart mitochondrial state 3 O₂ consumption sustained by malate-glutamate (21%) or by succinate (16%), and complexes I-III (27%), II-III (24%) and IV (22%) activities were lower in STZ group, when animals were sacrificed at day 14, i.e. ~11 days of hyperglycemia. In contrast, after 10 days of STZ-injection (~7 days of hyperglycemia), only the state 3 O₂ consumption sustained by malate-glutamate (23%) and its corresponding respiratory control (30%) were lower in diabetic rats, in accordance with complex I-III activity reduction (17%). Therefore, this time (~7 days of hyperglycemia) has been considered as an "early stage" of cardiac mitochondrial dysfunction. At this point, mitochondrial production rates of H₂O₂ (117%), NO (30%) and ONOO^- (~225%), and mtNOS expression (29%) were higher; and mitochondrial SOD activity (15%) and [GSH + GSSG] (28%) were lower in diabetic rats. Linear correlations between the modified mitochondrial parameters and glycemias were observed. PGC-1α expression was similar between groups, suggesting that mitochondrial biogenesis was not triggered in this initial phase of mitochondrial dysfunction. Consequently, complex I, H₂O₂ and NO could be considered early subcellular signals of cardiac mitochondrial dysfunction, with NO and H₂O₂ being located upstream de novo synthesis of mitochondria.

Stress hyperglycemia, cardiac glucotoxicity, and critically ill patient outcomes current clinical and pathophysiological evidence

Stress hyperglycemia is a transient increase in blood glucose during acute physiological stress in the absence of glucose homeostasis dysfunction. Its's presence has been described in critically ill patients who are subject to many physiological insults. In this regard, hyperglycemia and impaired glucose tolerance are also frequent in patients who are admitted to the intensive care unit for heart failure and cardiogenic shock. The hyperglycemia observed at the beginning of these cardiac disorders appears to be related to a variety of stress mechanisms. The release of major stress and steroid hormones, catecholamine overload, and glucagon all participate in generating a state of insulin resistance with increased hepatic glucose output and glycogen breakdown. In fact, the observed pathophysiological response, which appears to regulate a stress situation, is harmful because it induces mitochondrial impairment, oxidative stress-related injury to cells, endothelial damage, and dysfunction of several cellular channels. Paradigms are now being challenged by growing evidence of a phenomenon called glucotoxicity, providing an explanation for the benefits of lowering glucose levels with insulin therapy in these patients. In the present review, the authors present the data published on cardiac glucotoxicity and discuss the benefits of lowering plasma glucose to improve heart function and to positively affect the course of critical illness.

Histone Deacetylases in the Pathogenesis of Diabetic Cardiomyopathy

The global burden of diabetes mellitus and its complications are currently increasing. Diabetic cardiomyopathy (DCM) is the main cause of diabetes mellitus associated morbidity and mortality; therefore, a comprehensive understanding of DCM development is required for more effective treatment. A disorder of epigenetic posttranscriptional modification of histones in chromatin has been reported to be associated with the pathology of DCM. Recent studies have implicated that histone deacetylases could regulate cardiovascular and metabolic diseases in cellular processes including cardiac fibrosis, hypertrophy, oxidative stress and inflammation. Therefore in this review, we summarized the roles of histone deacetylases in the pathogenesis of DCM, aiming to provide insights into exploring potential preventative and therapeutic strategies of DCM.

Novel PGC-1α/ATF5 Axis Partly Activates UPRmt and Mediates Cardioprotective Role of Tetrahydrocurcumin in Pathological Cardiac Hypertrophy

Mitochondrial unfolding protein response (UPR^mt) effectively resists the pathological cardiac hypertrophy and improves the mitochondrial function. However, the specific activation mechanism and drugs that can effectively activate UPR^mt in the cardiac muscle are yet to be elucidated. The aim of this study was to determine the regulation role of UPR^mt on preventing pathological cardiac hypertrophy by tetrahydrocurcumin (THC) and explore its underlying molecular mechanism. Male C57BL/6J wild-type (WT) mice were divided into a control group and subjected to sham treatment for 4 weeks, and a test group which was subjected to transverse aortic constriction (TAC) surgery. Animals in the control and test group were orally administered THC (50 mg/kg) for 4 weeks after TAC procedure; an equivalent amount of saline was orally administered in the control sham-treated group and the TAC group. Subsequently, oxidative stress and UPR^mt markers were assessed in these mice, and cardiac hypertrophy, fibrosis, and cardiac function were tested. Small interfering RNA (siRNA) targeting proliferator-activated receptor-gamma coactivator (PGC)-1α and activating transcription factor 5 (ATF5) were used to determine the UPR^mt activation mechanism. THC supplement partly upregulated UPR^mt effectors and inhibited TAC-induced oxidative stress compared with TAC-operated WT mice, thereby substantially attenuating contractile dysfunction, cardiac hypertrophy, and fibrosis. Furthermore, PGC-1α knockdown blunted the UPR^mt activation and the cardioprotective role of THC. The interaction between PGC-1α and ATF5 was tested in neonatal rat cardiac myocytes under normal conditions. The results showed that PGC-1α was an upstream effector of ATF5 and partly activated UPR^mt. In vitro, phenylephrine- (PE-) induced cardiomyocyte hypertrophy caused ATF5 upregulating rather than downregulating corresponding to the downregulation of PGC-1α. The PGC-1α/ATF5 axis mediated the UPR^mt activation and stress-resistance role of THC in vitro. Collectively, the present study provides the first evidence that PGC-1 and ATF5 can form a signaling axis to partly activate UPR^mt that mediates the cardioprotective role of THC in pathological cardiac hypertrophy.

High-Density Lipoprotein-Targeted Therapies for Heart Failure

The main and common constituents of high-density lipoproteins (HDLs) are apolipoprotein A-I, cholesterol, and phospholipids. Biochemical heterogeneity of HDL particles is based on the variable presence of one or more representatives of at least 180 proteins, 200 lipid species, and 20 micro RNAs. HDLs are circulating multimolecular platforms that perform divergent functions whereby the potential of HDL-targeted interventions for treatment of heart failure can be postulated based on its pleiotropic effects. Several murine studies have shown that HDLs exert effects on the myocardium, which are completely independent of any impact on coronary arteries. Overall, HDL-targeted therapies exert a direct positive lusitropic effect on the myocardium, inhibit the development of cardiac hypertrophy, suppress interstitial and perivascular myocardial fibrosis, increase capillary density in the myocardium, and prevent the occurrence of heart failure. In four distinct murine models, HDL-targeted interventions were shown to be a successful treatment for both pre-existing heart failure with reduced ejection fraction (HFrEF) and pre-existing heart failure with preserved ejection fraction (HFrEF). Until now, the effect of HDL-targeted interventions has not been evaluated in randomized clinical trials in heart failure patients. As HFpEF represents an important unmet therapeutic need, this is likely the preferred therapeutic domain for clinical translation.

Diabetes and cardiovascular disease: inter-relation of risk factors and treatment

Background

The diabetes mellitus prevalence is still advancing and increasingly becoming one of the globally most severe and expensive chronic illnesses. The strong correlation between diabetes as well as the most prominent reason for diabetes and death in diabetic patients is cardiovascular disorders. Health conditions like dyslipidemia, hypertension, obesity, and other factors of risk like the risk of cardiovascular are frequent in diabetic persons and raise the likelihood of heart attacks.

Main text

In particular, several researchers have found diabetes mellitus-related biochemical pathways that raise the likelihood of cardiovascular disorder in people with diabetes individually. This review describes diabetes-cardiovascular disorder relationships, explores potential therapeutic mechanisms, addresses existing treatment, care, and describes the directions for the future for study.

Conclusion

Thus, in individuals with diabetes, it is important to concentrate on cardiovascular threat variables to reduce the illness’s lasting cardiovascular complications. Further work to enhance knowledge of the disease state and its impact on cardiovascular function is required to boost medical treatment and cardiovascular disorders result in people with diabetes.

Effect and Mechanism of Ganoderma lucidum Spores on Alleviation of Diabetic Cardiomyopathy in a Pilot in vivo Study

BACKGROUND

Ganoderma lucidum spores (GLS) exhibit disease prevention properties, but no study has been carried out on the anti-diabetic cardiomyopathy property of GLS. The aim of this study was to evaluate the hyperglycemia-mediated cardiomyopathy protection and mechanisms of GLS in streptozotocin (STZ)induced diabetic rats.

METHODS

Male SD rats were randomly divided into three groups. Two groups were given STZ (50 mg/kg, i.p.) treatment and when their fasting plasma glucose was above 16.7 mmol/L, among them, one group was given placebo, as diabetic group, and another group was given GLS (300 mg/kg) treatment. The group without STZ treatment was given placebo as a control group. The experiment lasted 70 days. The histology of myocardium and biomarkers of antioxidants, myocardial injury, pro-inflammatory cytokines, pro-apoptotic proteins and phosphorylation of key proteins in PI3K/AKT pathway were assessed.

RESULTS

Biochemical analysis showed that GLS treatment significantly reduced the blood glucose (-20.3%) and triglyceride (-20.4%) levels compared to diabetic group without treatment. GLS treatment decreased the content of MDA (-25.6%) and activity of lactate dehydrogenase (-18.9%) but increased the activity of GSH-Px (65.4%). Western blot analysis showed that GLS treatment reduced the expression of both alpha-smooth muscle actin and brain natriuretic peptide. Histological analysis on the cardiac tissue micrographs showed that GLS treatment reduced collagen fibrosis and glycogen reactivity in myocardium. Both Western blot and immunohistochemistry analyses showed that GLS treatment decreased the expression levels of pro-inflammatory factors (cytokines IL-1β, and TNF-α) as well as apoptosis regulatory proteins (Bax, caspase-3 and -9), but increased Bcl-2. Moreover, GLS treatment significantly increased the phosphorylation of key proteins involved in PI3K/AKT pathway, eg, p-AKT p-PI3K and mTOR.

CONCLUSION

The results indicated that GLS treatment alleviates diabetic cardiomyopathy by reducing hyperglycemia, oxidative stress, inflammation, apoptosis and further attenuating the fibrosis and myocardial dysfunction induced by STZ through stimulation of the PI3K/Akt/mTOR signaling pathway.

Pathophysiology, Clinical Characteristics of Diabetic Cardiomyopathy: Therapeutic Potential of Natural Polyphenols

Diabetic cardiomyopathy (DCM) is an outcome of disturbances in metabolic activities through oxidative stress, local inflammation, and fibrosis, as well as a prime cause of fatality worldwide. Cardiovascular disorders in diabetic individuals have become a challenge in diagnosis and formulation of treatment prototype. It is necessary to have a better understanding of cellular pathophysiology that reveal the therapeutic targets and prevent the progression of cardiovascular diseases due to hyperglycemia. Critical changes in levels of collagen and integrin have been observed in the extracellular matrix of heart, which was responsible for cardiac remodeling in diabetic patients. This review explored the understanding of the mechanisms of how the phytochemicals provide cardioprotection under diabetes along with the caveats and provide future perspectives on these agents as prototypes for the development of drugs for managing DCM. Thus, here we summarized the effect of various plant extracts and natural polyphenols tested in preclinical and cell culture models of diabetic cardiomyopathy. Further, the potential use of selected polyphenols that improved the therapeutic efficacy against diabetic cardiomyopathy is also illustrated.

Autophagy Inhibition Enables Nrf2 to Exaggerate the Progression of Diabetic Cardiomyopathy in Mice

Nuclear factor-erythroid factor 2-related factor 2 (Nrf2) may either ameliorate or worsen diabetic cardiomyopathy. However, the underlying mechanisms are poorly understood. Herein we report a novel mechanism of Nrf2-mediated myocardial damage in type 1 diabetes (T1D). Global Nrf2 knockout (Nrf2KO) hardly affected the onset of cardiac dysfunction induced by T1D but slowed down its progression in mice independent of sex. In addition, Nrf2KO inhibited cardiac pathological remodeling, apoptosis, and oxidative stress associated with both onset and advancement of cardiac dysfunction in T1D. Such Nrf2-mediated progression of diabetic cardiomyopathy was confirmed by a cardiomyocyte-restricted (CR) Nrf2 transgenic approach in mice. Moreover, cardiac autophagy inhibition via CR knockout of autophagy-related 5 gene (CR-Atg5KO) led to early onset and accelerated development of cardiomyopathy in T1D, and CR-Atg5KO-induced adverse phenotypes were rescued by additional Nrf2KO. Mechanistically, chronic T1D leads to glucolipotoxicity inhibiting autolysosome efflux, which in turn intensifies Nrf2-driven transcription to fuel lipid peroxidation while inactivating Nrf2-mediated antioxidant defense and impairing Nrf2-coordinated iron metabolism, thereby leading to ferroptosis in cardiomyocytes. These results demonstrate that diabetes over time causes autophagy deficiency, which turns off Nrf2-mediated defense while switching on an Nrf2-operated pathological program toward ferroptosis in cardiomyocytes, thereby worsening the progression of diabetic cardiomyopathy.

Value of circulating miRNA-21 in the diagnosis of subclinical diabetic cardiomyopathy

BACKGROUND

Diabetic cardiomyopathy (DCM) is a type of cardiac dysfunction that affects approximately 12% of diabetic patients, ultimately leading to heart failure or even death. However, there is currently no efficient or specific biomarker for DCM diagnosis.

METHODS

A total of 266 subjects with type II diabetes (T2DM) were enrolled in this study and were divided into the T2DM with cardiac dysfunction (DCM) group and T2DM without cardiac dysfunction (non-DCM) group. The diagnostic efficacy of miR-21 was determined and compared with that of serum hemoglobin A1c% (HbA1c%). Db/db mice and H9c2 cells stimulated with high glucose (HG)/high fatty acid (PA) were used as in vivo and in vitro models of DCM, respectively.

RESULTS

Through echocardiography and gated-myocardial perfusion imaging (gated-MPI), 49 patients were selected to be enrolled in the DCM group, with 49 matched controls in the non-DCM group. The circulating miR-21 levels were significantly decreased in the DCM group compared to the non-DCM group (P < 0.001). The diagnostic efficiency of miR-21 (area under the curve AUC = 0.899) was higher than that of other parameters, including HbA1c%. Moreover, when miR-21 was combined with the duration of diabetes, HbA1c%, and lipid profiles, the AUC was the highest (AUC = 0.939) and had the highest diagnostic efficiency. Furthermore, overexpression of miR-21 improved the impaired mitochondrial biogenesis and decreased the cardiomyocyte apoptosis induced by HG/PA, while inhibition of miR-21 exerted the opposite effects.

CONCLUSIONS

Our findings identify circulating miR-21 as a novel biomarker in the diagnosis of DCM and provide an underlying mechanism for miRNA-based therapy for the treatment of DCM.

TRIAL REGISTRATION

The study was approved by the Ethics Committee of the Third Affiliated Hospital of Soochow University and has been registered in the Chinese Clinical Trial Registry (ChiCTR1900027080).

[Rosmarinic acid inhibits high glucose-induced cardiomyocyte hypertrophy by activating Parkin-mediated mitophagy]

OBJECTIVE

To evaluate the effect of rosmarinic acid (RA) on mitophagy and hypertrophy of cardiomyocytes exposed to high glucose (HG).

METHODS

Rat cardiomyocytes (H9c2) exposed to HG (25 mmol/L) were treated with 50 μmol/L RA or with both RA treatment and Parkin siRNA transfection, with the cells cultured in normal glucose (5.5 mmol/L) and HG as the controls. The expressions of PINK1, Parkin and LC3II/LC3I in the cells were detected by Western blotting. The formation of mitochondrial autophagosomes was observed by transmission electron microscope. Flow cytometry was employed to detect the level of reactive oxygen species (ROS) and apoptotic rate of the cells. The activities of respiratory chain complex enzymes were measured by spectrophotometry. Fluorescence enzyme labeling and 3H-leucine labeling were used for determining the level of membrane potential and protein synthesis rate, respectively. The cell surface area was observed by light microscopy.

RESULTS

RA treatment significantly increased the expression levels of PINK1, Parkin and LC3-II/I (P < 0.05), promoted the formation of mitochondrail autophagosome, inhibited the production of reactive oxygen species (P < 0.05), restored the activities of mitochondrial respiratory chain complex enzymes and mitochondrial membrane potential (P < 0.05), inhibited apoptosis (P < 0.05), and reduced the cell surface area and protein synthesis rate of H9c2 cells induced by HG exposure (P < 0.05). The protective effects of RA against HG-induced oxidative stress and cardiomyocyte hypertrophy was obviously blocked by inhibition of mitophagy mediated by transfection with Parkin siRNA (P < 0.05).

CONCLUSIONS

RA can protect rat cardiomyocytes against oxidative stress injury and cardiomyocyte hypertrophy induced by HG by activating Parkin-mediated mitophagy.

Minireview: are SGLT2 inhibitors heart savers in diabetes?

Sodium-glucose cotransporter 2 (SGLT2) inhibitors, a class of drugs that promote urinary glucose excretion in the treatment of diabetes, have provoked large interest of scientific and professional community due to their positive and, somehow, unexpected results in the three major cardiovascular outcome trials (EMPA-REG OUTCOME trial with empagliflozin, CANVAS Program with canagliflozin, and DECLARE-TIMI 58 with dapagliflozin). In fact, along with the reduction of major adverse cardiovascular events, SGLT2 inhibitors reduced significantly hospitalization for heart failure regardless of existing atherosclerotic cardiovascular disease or a history of heart failure. The latter have reminded us of the frequent but neglected entity of diabetic cardiomyopathy which is currently poorly understood despite its great clinical importance. Physiological mechanisms responsible for the benefits of SGLT2 inhibitors are complex and multifactorial and still not well defined. Interestingly, the time frame of their effect excludes a glucose- and antiatherosclerotic-mediated effect. It would be of great importance to better understand SGLT2 inhibitor mechanisms of action since they could have a potential to be used in early stages of diabetes as cardioprotective agents. There are widely available biomarkers as well as echocardiography that are used in everyday clinical practice and could elucidate physiological mechanisms in the heart protection with SGLT2 inhibitors treatment but studies are still lacking. The purpose of this minireview is to summarize the latest concepts about SGLT2 inhibitors and its benefits regarding diabetic cardiomyopathy especially on its early stage development and to discuss controversies and potential future developments in the field.

Isoliquiritigenin attenuates diabetic cardiomyopathy via inhibition of hyperglycemia-induced inflammatory response and oxidative stress

BACKGROUND

Inflammation and oxidative stress play essential roles in the occurrence and progression of diabetic cardiomyopathy (DCM). Isoliquiritigenin (ISL), a natural chalcone, exhibits strong anti-inflammatory and antioxidant activities.

HYPOTHESIS/PURPOSE

In this study, we aimed to investigate the protective effects of ISL on DCM using high glucose (HG)-challenged cultured cardiomyocytes and streptozotocin (STZ)-induced diabetic mice.

STUDY DESIGN AND METHODS

Embryonic rat heart-derived H9c2 cells challenged with a high concentration of glucose were used to evaluate the anti-inflammatory and antioxidant effects of ISL. STZ-induced diabetic mice were used to study the effects of ISL in DCM in vivo. Furthermore, cardiac fibrosis, hypertrophy, and apoptosis were explored both in vitro and in vivo.

RESULTS

ISL effectively inhibited HG-induced hypertrophy, fibrosis, and apoptosis probably by alleviating the inflammatory response and oxidative stress in H9c2 cells. Results from in vivo experiments showed that ISL exhibited anti-inflammatory and antioxidant stress activities that were characterized by the attenuation of cardiac hypertrophy, fibrosis, and apoptosis, which resulted in the maintenance of cardiac function. The protective effects of ISL against inflammation and oxidative stress were mediated by the inhibition of mitogen-activated protein kinases (MAPKs) and induction of nuclear factor-erythroid 2 related factor 2 (Nrf2) signaling pathway, respectively.

CONCLUSION

Our results provided compelling evidence that ISL, by virtue of neutralizing excessive inflammatory response and oxidative stress, could be a promising agent in the treatment of DCM. Targeting the MAPKs and Nrf2 signaling pathway might be an effective therapeutic strategy for the prevention and treatment of DCM.

Dihydromyricetin Prevents Diabetic Cardiomyopathy via miR-34a Suppression by Activating Autophagy

PURPOSE

The pro-aging miRNA, miR-34a, is hyperactivated in the cardiac myocardial tissues of patients and mice with diabetes, leading to diabetic cardiomyopathy (DCM). Increasing evidence suggests that dihydromyricetin (DHM) can be used to effectively treat cardiomyopathy. In this study, we investigated whether DHM affects the expression of miR-34a in DCM.

METHODS

The expression of miR-34a in high-glucose-induced cardiomyocytes and in the heart tissue of diabetic mice was determined by microRNA isolation and quantitative reverse transcription-polymerase chain reaction. Lipofectamine 3000 was used to transfect cardiomyocytes with miR-34a inhibitor, miR-34a mimics, and miR-control. These agents were intravenously injected into the tail vein of streptozotocin-induced diabetic mice. Autophagy and apoptosis were assessed in high-glucose-induced cardiomyocytes and cardiac tissue in diabetic mice by western blotting, immunofluorescence, Masson staining, hematoxylin and eosin staining (H&E), and electron microscopy.

RESULTS

DHM clearly ameliorated the cardiac dysfunction in the diabetic mice. The expression of miR-34a was up-regulated in high-glucose-induced cardiomyocytes and in the hearts of diabetic mice, thus impairing autophagy. Treatment with DHM decreased the expression of miR-34a and rescued the impairment of autophagy in high-glucose-induced cardiomyocytes and in the heart tissue of diabetic mice, while the miR-34a mimic offset the effect of DHM with respect to the development of DCM by inhibiting autophagy.

CONCLUSIONS

By decreasing the expression of miR-34a, DHM restores impaired autophagy, and thus ameliorates DCM. Therefore, DHM may potentially be used in the treatment of DCM.

Dihydrotanshinone I Ameliorates Cardiac Hypertrophy in Diabetic Mice Induced by Chronic High-Fat Feeding

Salvia miltiorrhiza Bge. (Danshen) is widely used to improve blood circulation and the dredge meridian in traditional Chinese medicine. In the present study, we evaluated the effects of dihydrotanshinone I (DHTS), a natural product from Danshen, on chronic high-fat feeding-induced cardiac remodeling and dysfunction. DHTS (25 mg/kg, intraperitoneal) did not affect blood glucose, insulin levels, and glucose intolerance. However, it alleviated diastolic dysfunction induced by the high-fat diet, as indicated by the increase in the ratio of peak early filling velocity to peak late filling velocity of the mitral and suppression of the extension of the isovolumic relaxation phase of the left ventricle. Further investigations revealed that DHTS ameliorated high-fat induced cardiac hypertrophy in mice and suppressed insulin-induced enlargement of cardiomyocytes in vitro. In neonatal cardiomyocytes, DHTS restored insulin-induced suppression of CCAAT/enhancer-binding protein beta-2 isoform (CEBPβ) and the phosphorylation of glycogen synthase kinase-3β (GSK3β) and extracellular signal-regulated kinase (ERK). Taken together, our results indicated that DHTS ameliorated cardiac hypertrophy and diastolic dysfunction in high-fat-fed mice, probably through the inhibition of insulin-induced suppression of CEBPβ and phosphorylation of GSK3β and ERK in cardiomyocytes.

Transfer of a human gene variant associated with exceptional longevity improves cardiac function in obese type 2 diabetic mice through induction of the SDF-1/CXCR4 signalling pathway

AIMS

Homozygosity for a four-missense single-nucleotide polymorphism haplotype of the human BPIFB4 gene is enriched in long-living individuals. Delivery of this longevity-associated variant (LAV) improved revascularisation and reduced endothelial dysfunction and atherosclerosis in mice through a mechanism involving the stromal cell-derived factor-1 (SDF-1). Here, we investigated if delivery of the LAV-BPIFB4 gene may attenuate the progression of diabetic cardiomyopathy.

METHODS AND RESULTS

Compared with age-matched lean controls, diabetic db/db mice showed altered echocardiographic indices of diastolic and systolic function and histological evidence of microvascular rarefaction, lipid accumulation, and fibrosis in the myocardium. All these alterations, as well as endothelial dysfunction, were prevented by systemic LAV-BPIFB4 gene therapy using an adeno-associated viral vector serotype 9 (AAV9). In contrast, AAV9 wild-type-BPIFB4 exerted no benefit. Interestingly, LAV-BPIFB4-treated mice showed increased SDF-1 levels in peripheral blood and myocardium and up-regulation of the cardiac myosin heavy chain isoform alpha, a contractile protein that was reduced in diabetic hearts. SDF-1 up-regulation was instrumental to LAV-BPIFB4-induced benefit as both haemodynamic and structural improvements were inhibited by an orally active antagonist of the SDF-1 CXCR4 receptor.

CONCLUSIONS

In mice with type-2 diabetes, LAV-BPIFB4 gene therapy promotes an advantageous remodelling of the heart, allowing it to better withstand diabetes-induced stress. These results support the viability of transferring healthy characteristics of longevity to attenuate diabetic cardiac disease.

A novel oral glucagon-like peptide 1 receptor agonist protects against diabetic cardiomyopathy via alleviating cardiac lipotoxicity induced mitochondria dysfunction

Diabetic cardiomyopathy is one of the major cardiovascular complications of diabetes mellitus associated with left ventricular diastolic dysfunction. There are still no specific therapeutic guidelines for the disease. In recent years, glucagon-like peptide 1 receptor agonists were proved to exert cardioprotective effects in comprehensive studies. Therefore, we examined whether a novel oral availably glucagon-like peptide 1 receptor agonist, oral hypoglycemic peptide 2 (OHP2), could protect against diabetic cardiomyopathy in high-fat diets and continuous streptozocin injection induced rat models. After treatment for eight weeks, heart function was evaluated by echocardiography. As expected, OHP2 improved cardiac structure and function beyond glycemic control. Both hyperlipidemia and myocardium lipid accumulation were decreased by OHP2 treatment. In addition, OHP2 reversed oxidative stress and mitochondrial dysfunction in diabetic hearts. In vitro study suggested that OHP2 prevented palmitic acid-induced oxidative stress and mitochondrial dysfunction via suppressing intercellular lipid accumulation. Hence, our present findings pointed out that OHP2 is a promising oral glucagon-like peptide 1 receptor agonist for preventing diabetic cardiomyopathy.

Cellular, mitochondrial and molecular alterations associate with early left ventricular diastolic dysfunction in a porcine model of diabetic metabolic derangement

The prevalence of diabetic metabolic derangement (DMetD) has increased dramatically over the last decades. Although there is increasing evidence that DMetD is associated with cardiac dysfunction, the early DMetD-induced myocardial alterations remain incompletely understood. Here, we studied early DMetD-related cardiac changes in a clinically relevant large animal model. DMetD was established in adult male Göttingen miniswine by streptozotocin injections and a high-fat, high-sugar diet, while control animals remained on normal pig chow. Five months later left ventricular (LV) function was assessed by echocardiography and hemodynamic measurements, followed by comprehensive biochemical, molecular and histological analyses. Robust DMetD developed, evidenced by hyperglycemia, hypercholesterolemia and hypertriglyceridemia. DMetD resulted in altered LV nitroso-redox balance, increased superoxide production—principally due to endothelial nitric oxide synthase (eNOS) uncoupling—reduced nitric oxide (NO) production, alterations in myocardial gene-expression—particularly genes related to glucose and fatty acid metabolism—and mitochondrial dysfunction. These abnormalities were accompanied by increased passive force of isolated cardiomyocytes, and impaired LV diastolic function, evidenced by reduced LV peak untwist velocity and increased E/e′. However, LV weight, volume, collagen content, and cardiomyocyte cross-sectional area were unchanged at this stage of DMetD. In conclusion, DMetD, in a clinically relevant large-animal model results in myocardial oxidative stress, eNOS uncoupling and reduced NO production, together with an altered metabolic gene expression profile and mitochondrial dysfunction. These molecular alterations are associated with stiffening of the cardiomyocytes and early diastolic dysfunction before any structural cardiac remodeling occurs. Therapies should be directed to ameliorate these early DMetD-induced myocardial changes to prevent the development of overt cardiac failure.

Pompe disease: pathogenesis, molecular genetics and diagnosis

Pompe disease (PD) is a rare autosomal recessive disorder caused by mutations in the GAA gene, localized on chromosome 17 and encoding for acid alpha-1,4-glucosidase (GAA). Currently, more than 560 mutations spread throughout GAA gene have been reported. GAA catalyzes the hydrolysis of α-1,4 and α-1,6-glucosidic bonds of glycogen and its deficiency leads to lysosomal storage of glycogen in several tissues, particularly in muscle. PD is a chronic and progressive pathology usually characterized by limb-girdle muscle weakness and respiratory failure. PD is classified as infantile and childhood/adult forms. PD patients exhibit a multisystemic manifestation that depends on age of onset.

Early diagnosis is essential to prevent or reduce the irreversible organ damage associated with PD progression. Here, we make an overview of PD focusing on pathogenesis, clinical phenotypes, molecular genetics, diagnosis, therapies, autophagy and the role of miRNAs as potential biomarkers for PD.

Diabetic Cardiomyopathy: From Mechanism to Management in a Nutshell

Diabetic cardiomyopathy (DCM) is a significant complication of diabetes mellitus characterized by gradually failing heart with detrimental cardiac remodelings, such as fibrosis and diastolic and systolic dysfunction, which is not directly attributable to coronary artery disease. Insulin resistance and resulting hyperglycemia is the main trigger involved in the initiation of diabetic cardiomyopathy. There is a constellation of many pathophysiological events, such as lipotoxicity, oxidative stress, inflammation, inappropriate activation of the renin-angiotensin-aldosterone system, dysfunctional immune modulation promoting increased rate of cardiac cell injury, apoptosis, and necrosis, which ultimately culminates into interstitial fibrosis, cardiac stiffness, diastolic dysfunction, initially, and later systolic dysfunction too. These events finally lead to clinical heart failure of DCM. Herein, The pathophysiology of DCM is briefly discussed. Furthermore, potential therapeutic strategies currently used for DCM are also briefly mentioned.

Silencing of peroxisome proliferator-activated receptor-alpha alleviates myocardial injury in diabetic cardiomyopathy by downregulating 3-hydroxy-3-methylglutaryl-coenzyme A synthase 2 expression

Diabetic cardiomyopathy (DCM) is a cardiac disorder, which affects around 12% diabetic patients, resulting in overt heart death. Our initial bioinformatic analysis identified the differentially expressed gene 3-hydroxy-3-methylglutaryl-coenzyme A synthase 2 (HMGCS2) in DCM, which may be activated by peroxisome proliferator-activated receptor-alpha (PPARα) based on previous evidence. Therefore, the present study aims to explore the effect of PPARα on the development of DCM through regulating HMGCS2. The expression of PPARα and HMGCS2 was detected by reverse transcription quantitative polymerase chain reaction in cardiomyocytes and high-glucose-cultured cardiomyocytes. The proliferation and apoptosis of cardiomyocytes were examined by 5-ethynyl-2'-deoxyuridine assay and flow cytometry, separately. Mitoehondrial membrane potential (MMP) and intracellular reactive oxygen species (ROS) levels were determined. Then, the protein levels of B-cell lymphoma 2, Bcl-2-associated X protein, and cleaved Caspase-3 were detected by Western blot analysis. The myocardial apoptosis index, heart weight, and serum lipids of rats were examined. At last, the expressions of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), transforming growth factor β1 (TGFβ1), peroxisome proliferator activator receptor gamma coactivator-1 alpha (PGC1α), nuclear respiratory factor (NRF)-1, NRF-2, NAD(P)H oxidase 1, and superoxide dismutase-1 were examined. HMGCS2 was the most differentially expressed gene in DCM. The levels of HMGCS2 and PPARα were upregulated in patients with DCM. HMGCS2 silencing was shown to inhibit HMGCS2 expression to suppress the apoptosis of high-glucose-induced cardiomyocytes and the loss of MMP, reduce the accumulation of ROS, and promote cardiomyocyte proliferation. Silencing of HMGCS2 and PPARα alleviated myocardial injury, decreased blood glucose, and lipid in DCM rats, downregulated the expression of ANP, BNP, and TGFβ1 to reduce myocardial injury, and elevated PGC1α, NRF-1, and NRF-2 levels to enhance oxidative stress levels. Our results demonstrated that silencing of PPARα could alleviate cardiomyocyte injury and oxidative stress via a mechanism related to the downregulation of HMGCS2, which could provide a novel target for DCM treatment.

Curcumin protects cardiomyopathy damage through inhibiting the production of reactive oxygen species in type 2 diabetic mice

Type 2 diabetes mellitus (DM)-induced cardiomyopathy is a multifactorial and complex disease involving oxidative stress, lipids, and fibrosis. It is based on metabolic disorders and microvascular disease and causes extensive focal necrosis of the heart muscle. Curcumin (CUR) is a natural polyphenol isolated from turmeric rhizomes and plays an important role in the antioxidant, anti-apoptotic and anti-inflammatory effects of diabetes. Therefore, we established a mouse model of diabetic cardiomyopathy (DCM) in type 2 diabetic db/db mice in our study. We divided the experiment into three groups: the control group, DM group and DM + CUR group.We performed cardiac dissection on mice treated in different conditions and conducted special pathological staining on isolated cardiac tissue. We were surprised to find that a high glucose environment can promote cardiomyocyte apoptosis by TUNEL assay. In addition, after detecting dihydroethiidine (DHE), hematoxylin-eosin (H&E) and Oil Red O staining, we unexpectedly found that CUR can inhibit the production of reactive oxygen species (ROS), reduce myocardial apoptosis, and myocardial lipid accumulation. CUR upregulated the expression of Bcl-2, and downstream the expression of Bax and Caspase-3 proteins by immunohistochemical determination and western blotting. Therefore, these results suggest that CUR has a certain protective effect on diabetic cardiomyopathy by inhibiting the production of ROS.

Palmitate-induced toxicity is associated with impaired mitochondrial respiration and accelerated oxidative stress in cultured cardiomyocytes: The critical role of coenzyme Q9/10

Impaired mitochondrial function concomitant to enhanced oxidative stress-induced damage are well established mechanisms involved in hyperlipidemia-induced cardiotoxicity. Currently, limited information is available on the direct effect of myocardial lipid overload on endogenous coenzyme Q_9/10 (CoQ_9/10) levels in association with mitochondrial respiration and oxidative stress status. Here, such effects were explored by exposing H9c2 cardiomyocytes to various doses (0.15 to 1 mM) of palmitate for 24 h. The results demonstrated that palmitate doses ≥0.25 mM are enough to impair mitochondrial respiration and cause oxidative stress. Although endogenous CoQ_9/10 levels are enhanced by palmitate doses ≤0.5 mM, this is not enough to counteract oxidative stress, but is sufficient to maintain cell viability of cardiomyocytes. Palmitate doses >0.5 mM caused severe mitochondrial toxicity, including reduction of cell viability. Interestingly, enhancement of CoQ_9/10 levels with the lowest dose of palmitate (0.15 mM) was accompanied by a significantly reduction of CoQ₉ oxidation status, as well as low cytosolic production of reactive oxygen species. From the overall findings, it appears that CoQ_9/10 response may be crucial to improve mitochondrial function in conditions linked to hyperlipidemia-induced insult. Confirmation of such findings in relevant in vivo models remains essential to better understand the cardioprotective effects in association with improving endogenous CoQ_9/10 content.

Sodium-glucose cotransporter 2 inhibitors' mechanisms of action in heart failure

Three major cardiovascular outcome trials (CVOTs) with a new class of antidiabetic drugs - sodium-glucose cotransporter 2 (SGLT2) inhibitors (EMPA-REG OUTCOME trial with empagliflozin, CANVAS Program with canagliflozin, DECLARE-TIMI 58 with dapagliflozin) unexpectedly showed that cardiovascular outcomes could be improved possibly due to a reduction in heart failure risk, which seems to be the most sensitive outcome of SGLT2 inhibition. No other CVOT to date has shown any significant benefit on heart failure events. Even more impressive findings came recently from the DAPA-HF trial in patients with confirmed and well-treated heart failure: Dapagliflozin was shown to reduce heart failure risk for patients with heart failure with reduced ejection fraction regardless of diabetes status. Nevertheless, despite their possible wide clinical implications, there is much doubt about the mechanisms of action and a lot of questions to unravel, especially now when their benefits translated to non-diabetic patients, rising doubts about the validity of some current mechanistic assumptions.The time frame of their cardiovascular benefits excludes glucose-lowering and antiatherosclerotic-mediated effects and multiple other mechanisms, direct cardiac as well as systemic, are suggested to explain their early cardiorenal benefits. These are: Anti-inflammatory, antifibrotic, antioxidative, antiapoptotic properties, then renoprotective and hemodynamic effects, attenuation of glucotoxicity, reduction of uric acid levels and epicardial adipose tissue, modification of neurohumoral system and cardiac fuel energetics, sodium-hydrogen exchange inhibition. The most logic explanation seems that SGLT2 inhibitors timely target various mechanisms underpinning heart failure pathogenesis. All the proposed mechanisms of their action could interfere with evolution of heart failure and are discussed separately within the main text.

High-intensity interval training (HIIT) effectively enhances heart function via miR-195 dependent cardiomyopathy reduction in high-fat high-fructose diet-induced diabetic rats

Aims: Regarding the fact that up-regulation of miR-195 in diabetic hearts has a potential role in diabetic cardiomyopathy, the present study investigated whether continuous endurance training (CET) and high-intensity interval training (HIIT) reduces miR-195 expression and which exercise is effective in this regard.Methods: Diabetes was induced by high-fat high-fructose diet (HFHFD). Then, the rats were sub-divided into three categories; sedentary (HFHFD + SED), continuous endurance training (HFHFD + CET), and high-intensity interval training group (HFHFD + HIIT). After eight weeks of running, expression of miR-195 and myocardial function were evaluated.Results: HIIT effectively decreases the expression of miR-195 and increases the expression of Sirt1 and BCL-2 in diabetic rats compared with CET. Our results showed that HIIT compared with CET increases left ventricular ejection fraction (LVEF%) and fractional shortening (FS%).Conclusions: Our results indicated that exercise, especially HIIT is an appropriate strategy for reducing miR-195 and improving myocardial function in diabetic rats compared with CET.

Promotion of Adropin Expression by Hyperglycemia Is Associated with STAT3 Activation in Diabetic Rats

BACKGROUND

Adropin is a secreted polypeptide that has been demonstrated to play an important role in energy homeostasis and lipid metabolism. Signal transducer and activator of transcription 3 (STAT3) may promote the transcription of target genes including adropin. In the current study, we investigated the effect of adropin on glucose metabolism in diabetic rats and the mechanism that governs this effect was subsequently assessed.

MATERIALS AND METHODS

Rats received a single injection of streptozotocin to induce type 1 diabetes. The diabetic rats were treated with insulin or phloridzin, another antidiabetic agent through inhibition of glucose reabsorption, for 7 days. Plasma glucose levels and adropin levels were measured. The interaction between STAT3 and adropin was evaluated using the human hepatoma HepG2 cell line. HepG2 cells were pretreated with the specific antagonist Stattic or with STAT3-specific siRNAs to knockout STAT3. Changes in energy homeostasis-associated gene expression were measured using real-time PCR. The protein expression levels of pSTAT3 and STAT3 were measured using Western blotting.

RESULTS

In diabetic rats, the serum concentrations of adropin were increased in the vehicle-treated group and decreased in the insulin- or phloridzin-treated group. In liver tissues, the Enho expression level and the activity of STAT3 also showed similar tendencies. After HepG2 cells were treated with medium containing high glucose, the ratio of p-STAT3 to STAT3, Enho mRNA levels and reactive oxygen species expression levels in HepG2 cells were significantly increased in conjunction with increased glucose levels. The effect was inhibited after pretreatment with Stattic or knockdown with STAT3-specific siRNAs.

CONCLUSION

STAT3 is involved in the genetic regulation of adropin, increasing the levels of circulating adropin and promoting Enho expression in the livers of diabetic rats.

Allylmethylsulfide, a Sulfur Compound Derived from Garlic, Attenuates Isoproterenol-Induced Cardiac Hypertrophy in Rats

Allylmethylsulfide (AMS) is a novel sulfur metabolite found in the garlic-fed serum of humans and animals. In the present study, we have observed that AMS is safe on chronic administration and has a potential antihypertrophic effect. Chronic administration of AMS for 30 days did not cause any significant differences in the body weight, electrocardiogram, food intake, serum biochemical parameters, and histopathology of vital organs. Single-dose pharmacokinetics of AMS suggests that AMS is rapidly metabolized into Allylmethylsulfoxide (AMSO) and Allylmethylsulfone (AMSO₂). To evaluate the efficacy of AMS, cardiac hypertrophy was induced by subcutaneous implantation of ALZET® osmotic minipump containing isoproterenol (~5 mg/kg/day), cotreated with AMS (25 and 50 mg/kg/day) and enalapril (10 mg/kg/day) for 2 weeks. AMS and enalapril significantly reduced cardiac hypertrophy as studied by the heart weight to body weight ratio and mRNA expression of fetal genes (ANP and β-MHC). We have observed that TBARS, a parameter of lipid peroxidation, was reduced and the antioxidant enzymes (glutathione, catalase, and superoxide dismutase) were improved in the AMS and enalapril-cotreated hypertrophic hearts. The extracellular matrix (ECM) components such as matrix metalloproteinases (MMP2 and MMP9) were significantly upregulated in the diseased hearts; however, with the AMS and enalapril, it was preserved. Similarly, caspases 3, 7, and 9 were upregulated in hypertrophic hearts, and with the AMS and enalapril treatment, they were reduced. Further to corroborate this finding with in vitro data, we have checked the nuclear expression of caspase 3/7 in the H9c2 cells treated with isoproterenol and observed that AMS cotreatment reduced it significantly. Histopathological investigation of myocardium suggests AMS and enalapril treatment reduced fibrosis in hypertrophied hearts. Based on our experimental results, we conclude that AMS, an active metabolite of garlic, could reduce isoproterenol-induced cardiac hypertrophy by reducing oxidative stress, apoptosis, and stabilizing ECM components.

SIRT3 is a downstream target of PPAR-α implicated in high glucose-induced cardiomyocyte injury in AC16 cells

Diabetic cardiomyopathy (DCM) is a worldwide public health concern that continues to display rapid growth trends. This study investigated the function of sirtuin 3 (SIRT3), a primary mitochondrial deacetylase with important roles in antioxidant defense and oxidative metabolism, during high glucose-induced cardiomyocyte (AC16 cell) injury. Peroxisome proliferator-activated receptor-α (PPAR-α) is directly related to the occurrence of DCM. Hence, we further examined the relationship between SIRT3 and PPAR-α. AC16 cells were treated with various concentrations of glucose. Relative mRNA expression and protein levels were detected by RT-qPCR and western blot analysis, respectively. Cell proliferation and apoptosis were assessed using CCK8 and Annexin V-FITC apoptosis detection kits, respectively. DCFH-DA assay was used to measure reactive oxygen species (ROS) accumulation. The results indicated that high glucose treatment reduced the expression of mRNA and protein of SIRT3 and PPAR-α in AC16 cells. Moreover, high glucose inhibited cell proliferation, as well as induced apoptosis, intracellular hydrogen peroxide production, and JNK1/2 phosphorylation. These effects were antagonized by SIRT3 overexpression or treatment with the PPAR-α agonist, Wy14643. Conversely, inhibition of SIRT3 via 3-TYP led to similar phenomena as those induced by high glucose treatment in AC16 cells, which were blocked by Wy14643. Lastly, chromatin immunoprecipitation (ChIP) and luciferase assays demonstrated SIRT3 as a direct target of PPAR-α. Taken together, the results provide evidence for an important role of SIRT3 in high glucose-induced cardiomyocyte injury and regulation of JNK1/2 signaling. Further, SIRT3 is a direct downstream target of PPAR-α.

Strawberry fruit (Fragaria x ananassa cv. Romina) extenuates iron-induced cardiac oxidative injury via effects on redox balance, angiotensin-converting enzyme, purinergic activities, and metabolic pathways

The potential cardioprotective properties of strawberry fruit (Fragaria x ananassa) (SF) were investigated in cardiac tissues ex vivo. Oxidative injury was induced by incubating freshly harvested cardiac tissue homogenates from healthy Sprague Dawley male rats with 0.1 mM FeSO₄ for 30 min at 37°C. The induction of oxidative injury resulted in depleted levels of glutathione, superoxide dismutase, catalase, E-NTPDase activities, and HDL-c, while elevating the levels of malondialdehyde, angiotensin-converting enzyme, acetylcholinesterase, ATPase, lipase activities, cholesterol, triglyceride, and LDL-c. Co-incubation with SF significantly reversed these levels and activities with concomitant depletion of oxidative-induced metabolites and reactivation of oxidative-inactivated pathways, while limiting beta-oxidation of very long chain fatty acids and mitochondrial beta-oxidation of medium-chain saturated fatty acids pathways. These data portray the potential cardioprotective effects of strawberry fruits against oxidative-induced cardiopathy via the attenuation of oxidative stress, inhibition of ACE and acetylcholinesterase activities, and modulation of lipid dysmetabolism. PRACTICAL APPLICATIONS: Fruits and other fruit-based products have been enjoying wide acceptability among consumers due to their immense medicinal benefits particularly, on cardiovascular health. Strawberries are among the common fruits in the world. Over the years, cardiovascular diseases have been known to contribute greatly to global mortality irrespective of age. This study reports the potentials of strawberry fruits to protect against oxidative mediated cardiovascular dysfunctions. Thus, the fruits can be utilized as a cheap alternative for the development of nutraceuticals for maintaining cardiac health.

Glucose fluctuations promote vascular BK channels dysfunction via PKCα/NF-κB/MuRF1 signaling

Glucose fluctuations may contribute to large conductance calcium activated potassium (BK) channel dysfunction. However, the underlying mechanisms remain elusive. The aim of this study was to investigate the molecular mechanisms involved in BK channel dysfunction as a result of glucose fluctuations. A rat diabetic model was established through the injection of streptozotocin. Glucose fluctuations in diabetic rats were induced via consumption and starvation. Rat coronary arteries were isolated and coronary vascular tensions were measured after three weeks. Rat coronary artery smooth muscle cells were isolated and whole-cell BK channel currents were recorded using a patch clamp technique. Human coronary artery smooth muscle cells in vitro were used to explore the underlying mechanisms. After incubation with iberiotoxin (IBTX), the Δ tensions (% Max) of rat coronary arteries in the controlled diabetes mellitus (C-DM), the uncontrolled DM (U-DM) and the DM with glucose fluctuation (GF-DM) groups were found to be 84.46 ± 5.75, 61.89 ± 10.20 and 14.77 ± 5.90, respectively (P < .05), while the current densities of the BK channels in the three groups were 43.09 ± 4.35 pA/pF, 34.23 ± 6.07 pA/pF and 17.87 ± 4.33 pA/pF, respectively (P < .05). The Δ tensions (% Max) of rat coronary arteries after applying IBTX in the GF-DM rats injected with 0.9% sodium chloride (NaCl) (GF-DM + NaCl) and the GF-DM rats injected with N-acetyl-L-cysteine (NAC) (GF-DM + NAC) groups were found to be 8.86 ± 1.09 and 48.90 ± 10.85, respectively (P < .05). Excessive oxidative stress and the activation of protein kinase C (PKC) α and nuclear factor (NF)-κB induced by glucose fluctuations promoted the decrease of BK-β1 expression, while the inhibition of reactive oxygen species (ROS), PKCα, NF-κB and muscle ring finger protein 1 (MuRF1) reversed this effect. Glucose fluctuations aggravate BK channel dysfunction via the ROS overproduction and the PKCα/NF-κB/MuRF1 signaling pathway.

Basic Mechanisms of Diabetic Heart Disease

Diabetes mellitus predisposes affected individuals to a significant spectrum of cardiovascular complications, one of the most debilitating in terms of prognosis is heart failure. Indeed, the increasing global prevalence of diabetes mellitus and an aging population has given rise to an epidemic of diabetes mellitus-induced heart failure. Despite the significant research attention this phenomenon, termed diabetic cardiomyopathy, has received over several decades, understanding of the full spectrum of potential contributing mechanisms, and their relative contribution to this heart failure phenotype in the specific context of diabetes mellitus, has not yet been fully resolved. Key recent preclinical discoveries that comprise the current state-of-the-art understanding of the basic mechanisms of the complex phenotype, that is, the diabetic heart, form the basis of this review. Abnormalities in each of cardiac metabolism, physiological and pathophysiological signaling, and the mitochondrial compartment, in addition to oxidative stress, inflammation, myocardial cell death pathways, and neurohumoral mechanisms, are addressed. Further, the interactions between each of these contributing mechanisms and how they align to the functional, morphological, and structural impairments that characterize the diabetic heart are considered in light of the clinical context: from the disease burden, its current management in the clinic, and where the knowledge gaps remain. The need for continued interrogation of these mechanisms (both known and those yet to be identified) is essential to not only decipher the how and why of diabetes mellitus-induced heart failure but also to facilitate improved inroads into the clinical management of this pervasive clinical challenge.

Multi-Omics Analysis of Diabetic Heart Disease in the db/db Model Reveals Potential Targets for Treatment by a Longevity-Associated Gene

Characterisation of animal models of diabetic cardiomyopathy may help unravel new molecular targets for therapy. Long-living individuals are protected from the adverse influence of diabetes on the heart, and the transfer of a longevity-associated variant (LAV) of the human BPIFB4 gene protects cardiac function in the db/db mouse model. This study aimed to determine the effect of LAV-BPIFB4 therapy on the metabolic phenotype (ultra-high-performance liquid chromatography-mass spectrometry, UHPLC-MS) and cardiac transcriptome (next-generation RNAseq) in db/db mice. UHPLC-MS showed that 493 cardiac metabolites were differentially modulated in diabetic compared with non-diabetic mice, mainly related to lipid metabolism. Moreover, only 3 out of 63 metabolites influenced by LAV-BPIFB4 therapy in diabetic hearts showed a reversion from the diabetic towards the non-diabetic phenotype. RNAseq showed 60 genes were differentially expressed in hearts of diabetic and non-diabetic mice. The contrast between LAV-BPIFB4- and vehicle-treated diabetic hearts revealed eight genes differentially expressed, mainly associated with mitochondrial and metabolic function. Bioinformatic analysis indicated that LAV-BPIFB4 re-programmed the heart transcriptome and metabolome rather than reverting it to a non-diabetic phenotype. Beside illustrating global metabolic and expressional changes in diabetic heart, our findings pinpoint subtle changes in mitochondrial-related proteins and lipid metabolism that could contribute to LAV-BPIFB4-induced cardio-protection in a murine model of type-2 diabetes.

Therapeutic approaches to diabetic cardiomyopathy: Targeting the antioxidant pathway

The global epidemic of cardiovascular disease continues unabated and remains the leading cause of death both in the US and worldwide. We hereby summarize the available therapies for diabetes and cardiovascular disease in diabetics. Clearly, the current approaches to diabetic heart disease often target the manifestations and certain mediators but not the specific pathways leading to myocardial injury, remodeling and dysfunction. Better understanding of the molecular events determining the evolution of diabetic cardiomyopathy will provide insight into the development of specific and targeted therapies. Recent studies largely increased our understanding of the role of enhanced inflammatory response, ROS production, as well as the contribution of Cyp-P450-epoxygenase-derived epoxyeicosatrienoic acid (EET), Peroxisome Proliferator-Activated Receptor Gamma Coactivator-1α (PGC-1α), Heme Oxygenase (HO)-1 and 20-HETE in pathophysiology and therapy of cardiovascular disease. PGC-1α increases production of the HO-1 which has a major role in protecting the heart against oxidative stress, microcirculation and mitochondrial dysfunction. This review describes the potential drugs and their downstream targets, PGC-1α and HO-1, as major loci for developing therapeutic approaches beside diet and lifestyle modification for the treatment and prevention of heart disease associated with obesity and diabetes.

Diabetic cardiomyopathy: molecular mechanisms, detrimental effects of conventional treatment, and beneficial effects of natural therapy

ABSTARCT

Diabetic complications are among the largely exigent health problems currently. Cardiovascular complications, including diabetic cardiomyopathy (DCM), account for more than 80% of diabetic deaths. Investigators are exploring new therapeutic targets to slow or abate diabetes because of the growing occurrence and augmented risk of deaths due to its complications. Research on rodent models of type 1 and type 2 diabetes mellitus, and the use of genetic engineering techniques in mice and rats have significantly sophisticated for our understanding of the molecular mechanisms in human DCM. DCM is featured by pathophysiological mechanisms that are hyperglycemia, insulin resistance, oxidative stress, left ventricular hypertrophy, damaged left ventricular systolic and diastolic functions, myocardial fibrosis, endothelial dysfunction, myocyte cell death, autophagy, and endoplasmic reticulum stress. A number of molecular and cellular pathways, such as cardiac ubiquitin proteasome system, FoxO transcription factors, hexosamine biosynthetic pathway, polyol pathway, protein kinase C signaling, NF-κB signaling, peroxisome proliferator-activated receptor signaling, Nrf2 pathway, mitogen-activated protein kinase pathway, and micro RNAs, play a major role in DCM. Currently, there are a few drugs for the management of DCM and some of them have considerable adverse effects. So, researchers are focusing on the natural products to ameliorate it. Hence, in this review, we discuss the pathogical, molecular, and cellular mechanisms of DCM; the current diagnostic methods and treatments; adverse effects of conventional treatment; and beneficial effects of natural product-based therapeutics, which may pave the way to new treatment strategies. Graphical Abstract.

From the gut to the heart: L. plantarum and inulin administration as a novel approach to control cardiac apoptosis via 5-HT2B and TrkB receptors in diabetes

BACKGROUND & AIMS

Type 2 diabetes mellitus, as a metabolic disorder, can lead to diabetic cardiomyopathy, identified by cardiomyocyte apoptosis and myocardial fibrosis. Brain-derived neurotrophic factor (BDNF) and serotonin are two neurotransmitters that can control cardiomyocyte apoptosis and myocardial fibrosis through their cardiac receptors. In the present study, we investigated the impacts of L. plantarum and inulin supplementation on the inhibition of cardiac apoptosis and fibrosis by modulating intestinal, serum, and cardiac levels of serotonin and BDNF as well as their cardiac receptors.

METHODS

Diabetes was induced by a high-fat diet and streptozotocin in male Wistar rats. Rats were divided into six groups and were supplemented with L. plantarum, inulin or their combination for 8 weeks. Finally, the rats were killed and levels of intestinal, serum, and cardiac parameters were evaluated.

RESULTS

Concurrent administration of L. plantarum and inulin caused a significant rise in the expression of cardiac serotonin and BDNF receptors (P < 0.001) as well as a significant fall in cardiac interstitial and perivascular fibrosis (P < 0.001, both) and apoptosis (P = 0.01). Moreover, there was a strong correlation of cardiac 5-Hydroxytryptamine 2B (5-HT2B) and tropomyosin receptor kinase B (TrkB) receptors with interstitial/perivascular fibrosis and apoptosis (P < 0.001, both).

CONCLUSIONS/INTERPRETATION

Results revealed beneficial effects of L. plantarum, inulin or their combination on intestinal, serum, and cardiac serotonin and BDNF accompanied by higher expression of their cardiac receptors and lower levels of cardiac apoptotic and fibrotic markers. It seems that L. plantarum and inulin supplementation could be considered as a novel adjunct therapy to reduce cardiac complications of type 2 diabetes mellitus.

Diabetic Cardiomyopathy and Ischemic Heart Disease: Prevention and Therapy by Exercise and Conditioning

Metabolic syndrome, diabetes, and ischemic heart disease are among the leading causes of death and disability in Western countries. Diabetic cardiomyopathy is responsible for the most severe signs and symptoms. An important strategy for reducing the incidence of cardiovascular disease is regular exercise. Remote ischemic conditioning has some similarity with exercise and can be induced by short periods of ischemia and reperfusion of a limb, and it can be performed in people who cannot exercise. There is abundant evidence that exercise is beneficial in diabetes and ischemic heart disease, but there is a need to elucidate the specific cardiovascular effects of emerging and unconventional forms of exercise in people with diabetes. In addition, remote ischemic conditioning may be considered among the options to induce beneficial effects in these patients. The characteristics and interactions of diabetes and ischemic heart disease, and the known effects of exercise and remote ischemic conditioning in the presence of metabolic syndrome and diabetes, are analyzed in this brief review.