Reactive oxygen species signalling in the diabetic heart: emerging prospect for therapeutic targeting

Decoding ferroptosis: Revealing the hidden assassin behind cardiovascular diseases

The discovery of regulatory cell death processes has driven innovation in cardiovascular disease (CVD) therapeutic strategies. Over the past decade, ferroptosis, an iron-dependent form of regulated cell death driven by excessive lipid peroxidation, has been shown to drive the development of multiple CVDs. This review provides insights into the evolution of the concept of ferroptosis, the similarities and differences with traditional modes of programmed cell death (e.g., apoptosis, autophagy, and necrosis), as well as the core regulatory mechanisms of ferroptosis (including cystine/glutamate transporter blockade, imbalance of iron metabolism, and lipid peroxidation). In addition, it provides not only a detailed review of the role of ferroptosis and its therapeutic potential in widely studied CVDs such as coronary atherosclerotic heart disease, myocardial infarction, myocardial ischemia/reperfusion injury, heart failure, cardiomyopathy, and aortic aneurysm but also an overview of the phenomenon and therapeutic perspectives of ferroptosis in lesser-addressed CVDs such as cardiac valvulopathy, pulmonary hypertension, and sickle cell disease. This article aims to integrate this knowledge to provide a comprehensive view of ferroptosis in a wide range of CVDs and to drive innovation and progress in therapeutic strategies in this field.

Therapeutic strategies targeting mechanisms of macrophages in diabetic heart disease

Diabetic heart disease (DHD) is a serious complication in patients with diabetes. Despite numerous studies on the pathogenic mechanisms and therapeutic targets of DHD, effective means of prevention and treatment are still lacking. The pathogenic mechanisms of DHD include cardiac inflammation, insulin resistance, myocardial fibrosis, and oxidative stress. Macrophages, the primary cells of the human innate immune system, contribute significantly to these pathological processes, playing an important role in human disease and health. Therefore, drugs targeting macrophages hold great promise for the treatment of DHD. In this review, we examine how macrophages contribute to the development of DHD and which drugs could potentially be used to target macrophages in the treatment of DHD.

The mechanisms and therapeutic potential of clopidogrel in mitigating diabetic cardiomyopathy in db/db mice

Clopidogrel has been shown to play a protective role against diabetic nephropathy. However, whether clopidogrel exerts a protective effect against diabetic cardiomyopathy (DCM) is unknown. Three-month-old male db/db mice were administered clopidogrel daily at doses of 5, 10, and 20 mg/kg by gavage for 5 months. Here, we showed that clopidogrel effectively attenuated diabetes-induced cardiac hypertrophy and cardiac dysfunction by inhibiting cardiac fibrosis, inflammatory responses, and oxidative stress damage in db/db mice. Diabetes-induced cardiac fibrosis was inhibited by clopidogrel treatment via blockade of the TGF-β1/Smad3/P2RY12 pathway and inhibition of macrophage infiltration in db/db mice. The protective effects of clopidogrel against oxidative damage were mediated by the induction of the Nrf2 signaling pathway. Taken together, our findings provide strong evidence that clopidogrel is a promising effective agent for the treatment of DCM by alleviating diabetes-induced cardiac hypertrophy and dysfunction. P2RY12 might be an effective target for the treatment of DCM.

Paeoniflorin confers ferroptosis resistance by regulating the gut microbiota and its metabolites in diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) is closely related to ferroptosis, a new type of cell death that mainly manifests as intracellular iron accumulation and lipid peroxidation. Paeoniflorin (PA) helps to improve impaired glucose tolerance, influences the distribution of the intestinal flora, and induces significant resistance to ferroptosis in several models. In this study, we found that PA improved cardiac dysfunction in mice with DCM by alleviating myocardial damage, resisting oxidative stress and ferroptosis, and changing the community composition and structure of the intestinal microbiota. Metabolomics analysis revealed that PA-treated fecal microbiota transplantation affected metabolites in DCM mice. Based on in vivo and in vitro experiments, 11,12-epoxyeicosatrienoic acid (11,12-EET) may serve as a key contributor that mediates the cardioprotective and antiferroptotic effects of PA-treated fecal microbiota transplantation (FMT) in DCM mice.NEW & NOTEWORTHY This study demonstrated for the first time that paeoniflorin (PA) exerts protective effects in diabetic cardiomyopathy mice by alleviating myocardial damage, resisting ferroptosis, and changing the community composition and structure of the intestinal microbiota, and 11,12-epoxyeicosatrienoic acid (11,12-EET) may serve as a key contributor in its therapeutic efficacy.

Mitochondrial Dysfunction in Heart Failure: From Pathophysiological Mechanisms to Therapeutic Opportunities

Mitochondrial dysfunction, a feature of heart failure, leads to a progressive decline in bioenergetic reserve capacity, consisting in a shift of energy production from mitochondrial fatty acid oxidation to glycolytic pathways. This adaptive process of cardiomyocytes does not represent an effective strategy to increase the energy supply and to restore the energy homeostasis in heart failure, thus contributing to a vicious circle and to disease progression. The increased oxidative stress causes cardiomyocyte apoptosis, dysregulation of calcium homeostasis, damage of proteins and lipids, leakage of mitochondrial DNA, and inflammatory responses, finally stimulating different signaling pathways which lead to cardiac remodeling and failure. Furthermore, the parallel neurohormonal dysregulation with angiotensin II, endothelin-1, and sympatho-adrenergic overactivation, which occurs in heart failure, stimulates ventricular cardiomyocyte hypertrophy and aggravates the cellular damage. In this review, we will discuss the pathophysiological mechanisms related to mitochondrial dysfunction, which are mainly dependent on increased oxidative stress and perturbation of the dynamics of membrane potential and are associated with heart failure development and progression. We will also provide an overview of the potential implication of mitochondria as an attractive therapeutic target in the management and recovery process in heart failure.

Effect of exercise on improving myocardial mitochondrial function in decreasing diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) is a significant cause of heart failure in patients with diabetes, and its pathogenesis is closely related to myocardial mitochondrial injury and functional disability. Studies have shown that the development of diabetic cardiomyopathy is related to disorders in mitochondrial metabolic substrates, changes in mitochondrial dynamics, an imbalance in mitochondrial Ca2+ regulation, defects in the regulation of microRNAs, and mitochondrial oxidative stress. Physical activity may play a role in resistance to the development of diabetic cardiomyopathy by improving myocardial mitochondrial biogenesis, the level of autophagy and dynamic changes in fusion and division; enhancing the ability to cope with oxidative stress; and optimising the metabolic substrates of the myocardium. This paper puts forward a new idea for further understanding the specific mitochondrial mechanism of the occurrence and development of diabetic cardiomyopathy and clarifying the role of exercise-mediated myocardial mitochondrial changes in the prevention and treatment of diabetic cardiomyopathy. This is expected to provide a new theoretical basis for exercise to reduce diabetic cardiomyopathy symptoms.

The study of the mechanism of non-coding RNA regulation of programmed cell death in diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) represents a distinct myocardial disorder elicited by diabetes mellitus, characterized by aberrations in myocardial function and structural integrity. This pathological condition predominantly manifests in individuals with diabetes who do not have concurrent coronary artery disease or hypertension. An escalating body of scientific evidence substantiates the pivotal role of programmed cell death (PCD)-encompassing apoptosis, autophagy, pyroptosis, ferroptosis, and necroptosis-in the pathogenic progression of DCM, thereby emerging as a prospective therapeutic target. Additionally, numerous non-coding RNAs (ncRNAs) have been empirically verified to modulate the biological processes underlying programmed cell death, consequently influencing the evolution of DCM. This review systematically encapsulates prevalent types of PCD manifest in DCM as well as nascent discoveries regarding the regulatory influence of ncRNAs on programmed cell death in the pathogenesis of DCM, with the aim of furnishing novel insights for the furtherance of research in PCD-associated disorders relevant to DCM.

Primordial Drivers of Diabetes Heart Disease: Comprehensive Insights into Insulin Resistance

Insulin resistance has been regarded as a hallmark of diabetes heart disease (DHD). Numerous studies have shown that insulin resistance can affect blood circulation and myocardium, which indirectly cause cardiac hypertrophy and ventricular remodeling, participating in the pathogenesis of DHD. Meanwhile, hyperinsulinemia, hyperglycemia, and hyperlipidemia associated with insulin resistance can directly impair the metabolism and function of the heart. Targeting insulin resistance is a potential therapeutic strategy for the prevention of DHD. Currently, the role of insulin resistance in the pathogenic development of DHD is still under active research, as the pathological roles involved are complex and not yet fully understood, and the related therapeutic approaches are not well developed. In this review, we describe insulin resistance and add recent advances in the major pathological and physiological changes and underlying mechanisms by which insulin resistance leads to myocardial remodeling and dysfunction in the diabetic heart, including exosomal dysfunction, ferroptosis, and epigenetic factors. In addition, we discuss potential therapeutic approaches to improve insulin resistance and accelerate the development of cardiovascular protection drugs.

Potential Underlying Mechanisms Explaining the Cardiorenal Benefits of Sodium-Glucose Cotransporter 2 Inhibitors

There is a bidirectional pathophysiological interaction between the heart and the kidneys, and prolonged physiological stress to the heart and/or the kidneys can cause adverse cardiorenal complications, including but not limited to subclinical cardiomyopathy, heart failure and chronic kidney disease. Whilst more common in individuals with Type 2 diabetes, cardiorenal complications also occur in the absence of diabetes. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) were initially approved to reduce hyperglycaemia in patients with Type 2 diabetes. Recently, these agents have been shown to significantly improve cardiovascular and renal outcomes in patients with and without Type 2 diabetes, demonstrating a robust reduction in hospitalisation for heart failure and reduced risk of progression of chronic kidney disease, thus gaining approval for use in treatment of heart failure and chronic kidney disease. Numerous potential mechanisms have been proposed to explain the cardiorenal effects of SGLT2i. This review provides a simplified summary of key potential cardiac and renal mechanisms underlying the cardiorenal benefits of SGT2i and explains these mechanisms in the clinical context. Key mechanisms related to the clinical effects of SGLT2i on the heart and kidneys explained in this publication include their impact on (1) tissue oxygen delivery, hypoxia and resultant ischaemic injury, (2) vascular health and function, (3) substrate utilisation and metabolic health and (4) cardiac remodelling. Knowing the mechanisms responsible for SGLT2i-imparted cardiorenal benefits in the clinical outcomes will help healthcare practitioners to identify more patients that can benefit from the use of SGLT2i.

Single-cell analysis reveals lysyl oxidase (Lox)+ fibroblast subset involved in cardiac fibrosis of diabetic mice

INTRODUCTION

Myocardial fibrosis and cardiac dysfunction are the main characteristics of diabetic heart disease. However, the molecular mechanisms underlying diabetic myocardial fibrosis remain unclear.

OBJECTIVES

This study aimed to investigate the heterogeneity of cardiac fibroblasts in diabetic mice and its possible mechanism in the development of diabetic myocardial fibrosis.

METHODS

We established a diabetic mouse model by injecting mice with streptozotocin. The overall cell profiles in diabetic hearts were analyzed using single-cell RNA transcriptomic techniques. Cardiac function was evaluated by echocardiography. Cardiac fibrosis was assessed by Masson's trichrome and Sirius red staining. Protein expression was analyzed using Western blotting and immunofluorescence staining.

RESULTS

A total of 11,585 cells were captured in control (Ctrl) and diabetic (DM) hearts. Twelve cell types were identified in this study. The number of fibroblasts was significantly higher in the DM hearts than in the Ctrl group. The fibroblasts were further re-clustered into nine subsets. Interestingly, cluster 4 fibroblasts were significantly increased in diabetic hearts compared with other fibroblast clusters. Lysyl oxidase (Lox) was highly expressed in DM fibroblasts (especially in cluster 4). Beta-aminopropionitrile, a Lox inhibitor, inhibited collagen expression and alleviated cardiac dysfunction in the diabetic group. Lysyl oxidase inhibition also reduced high glucose-induced collagen protein upregulation in primary fibroblasts. Moreover, a TGF-β receptor inhibitor not only prevented an increase in Lox and Col I but also inhibited the phosphorylation of Smad2/3 in fibroblasts.

CONCLUSIONS

This study revealed the heterogeneity of cardiac fibroblasts in diabetic mice for the first time. Fibroblasts with high expression of Lox (cluster 4 fibroblasts) were identified to play a crucial role in fibrosis in diabetic heart disease. The findings of this study may provide a possible therapeutic target for interstitial fibrosis.

Metabolic mitochondrial alterations prevail in the female rat heart 8 weeks after exercise cessation

BACKGROUND

The consumption of high-caloric diets strongly contributes to the development of non-communicable diseases (NCDs), including cardiovascular disease, the leading cause of mortality worldwide. Exercise (along with diet intervention) is one of the primary non-pharmacological approaches to promote a healthier lifestyle and counteract the rampant prevalence of NCDs. The present study evaluated the effects of exercise cessation after a short period training on the cardiac metabolic and mitochondrial function of female rats.

METHODS

Seven-week-old female Sprague-Dawley rats were fed a control or a high-fat, high-sugar (HFHS) diet and, after 7 weeks, the animals were kept on a sedentary lifestyle or submitted to endurance exercise for 3 weeks (6 days per week, 20-60 min/day). The cardiac samples were analysed 8 weeks after exercise cessation.

RESULTS

The consumption of the HFHS diet triggered impaired glucose tolerance, whereas the HFHS diet and physical exercise resulted in different responses in plasma adiponectin and leptin levels. Cardiac mitochondrial respiration efficiency was decreased by the HFHS diet consumption, which led to reduced ATP and increased NAD(P)H mitochondrial levels, which remained prevented by exercise 8 weeks after cessation. Exercise training-induced cardiac adaptations in redox balance, namely increased relative expression of Nrf2 and downstream antioxidant enzymes persist after an eight-week exercise cessation period.

CONCLUSIONS

Endurance exercise modulated cardiac redox balance and mitochondrial efficiency in female rats fed a HFHS diet. These findings suggest that exercise may elicit cardiac adaptations crucial for its role as a non-pharmacological intervention for individuals at risk of developing NCDs.

The mechanism of ferroptosis and its related diseases

Ferroptosis, a regulated form of cellular death characterized by the iron-mediated accumulation of lipid peroxides, provides a novel avenue for delving into the intersection of cellular metabolism, oxidative stress, and disease pathology. We have witnessed a mounting fascination with ferroptosis, attributed to its pivotal roles across diverse physiological and pathological conditions including developmental processes, metabolic dynamics, oncogenic pathways, neurodegenerative cascades, and traumatic tissue injuries. By unraveling the intricate underpinnings of the molecular machinery, pivotal contributors, intricate signaling conduits, and regulatory networks governing ferroptosis, researchers aim to bridge the gap between the intricacies of this unique mode of cellular death and its multifaceted implications for health and disease. In light of the rapidly advancing landscape of ferroptosis research, we present a comprehensive review aiming at the extensive implications of ferroptosis in the origins and progress of human diseases. This review concludes with a careful analysis of potential treatment approaches carefully designed to either inhibit or promote ferroptosis. Additionally, we have succinctly summarized the potential therapeutic targets and compounds that hold promise in targeting ferroptosis within various diseases. This pivotal facet underscores the burgeoning possibilities for manipulating ferroptosis as a therapeutic strategy. In summary, this review enriched the insights of both investigators and practitioners, while fostering an elevated comprehension of ferroptosis and its latent translational utilities. By revealing the basic processes and investigating treatment possibilities, this review provides a crucial resource for scientists and medical practitioners, aiding in a deep understanding of ferroptosis and its effects in various disease situations.

Microalgae-material hybrid for enhanced photosynthetic energy conversion: a promising path towards carbon neutrality

Photosynthetic energy conversion for high-energy chemicals generation is one of the most viable solutions in the quest for sustainable energy towards carbon neutrality. Microalgae are fascinating photosynthetic organisms, which can directly convert solar energy into chemical energy and electrical energy. However, microalgal photosynthetic energy has not yet been applied on a large scale due to the limitation of their own characteristics. Researchers have been inspired to couple microalgae with synthetic materials via biomimetic assembly and the resulting microalgae-material hybrids have become more robust and even perform new functions. In the past decade, great progress has been made in microalgae-material hybrids, such as photosynthetic carbon dioxide fixation, photosynthetic hydrogen production, photoelectrochemical energy conversion and even biochemical energy conversion for biomedical therapy. The microalgae-material hybrid offers opportunities to promote artificially enhanced photosynthesis research and synchronously inspires investigation of biotic-abiotic interface manipulation. This review summarizes current construction methods of microalgae-material hybrids and highlights their implication in energy and health. Moreover, we discuss the current problems and future challenges for microalgae-material hybrids and the outlook for their development and applications. This review will provide inspiration for the rational design of the microalgae-based semi-natural biohybrid and further promote the disciplinary fusion of material science and biological science.

Celastrol attenuates streptozotocin-induced diabetic cardiomyopathy in mice by inhibiting the ACE / Ang II / AGTR1 signaling pathway

BACKGROUND

Heart failure is closely correlated with diabetic cardiomyopathy (DCM) and can lead to mortality. Celastrol has long been utilized for the treatment of immune and inflammatory disorders. However, whether celastrol would exert protective effects on DCM has not been determined. This work aimed to explore the protective actions of celastrol on DCM and unravel the underlying mechanisms involved.

METHODS

A DCM model was constructed in mice by intraperitoneal administration of streptozotocin. ELISA and echocardiography were performed to examine myocardial injury markers and cardiac function, respectively. Morphological changes and fibrosis were assessed using H&E staining and Masson's staining. Inflammatory cytokines and fibrotic markers were detected by ELISA and RT-PCR. Endothelial nitric oxide synthase, apoptosis, and reactive oxygen species were detected by microscopic staining. Network pharmacology approaches, molecular docking analysis, ELISA, and Western blot were used for mechanism studies.

RESULTS

Celastrol alleviated diabetes-induced cardiac injury and remodeling. Celastrol also suppressed diabetes-induced production of inflammatory cytokines and reactive oxygen species, as well as cardiomyocyte apoptosis. The cardioprotective effects of celastrol were associated with its inhibition on the angiotensin-converting enzyme / angiotensin II / angiotensin II receptor type 1 signaling pathway.

CONCLUSION

Celastrol exhibits significant potential as an effective cardioprotective drug for DCM treatment. The underlying mechanisms can be attributed to the blockage of celastrol on the angiotensin-converting enzyme signaling pathway.

PLAC8-Mediated Activation of NOX4 Signalling Restores Angiogenic Function of Endothelial Colony-Forming Cells in Experimental Hypoxia

Ischaemic cardiovascular disease is associated with tissue hypoxia as a significant determinant of angiogenic dysfunction and adverse remodelling. While cord blood-derived endothelial colony-forming cells (CB-ECFCs) hold clear therapeutic potential due to their enhanced angiogenic and proliferative capacity, their impaired functionality within the disease microenvironment represents a major barrier to clinical translation. The aim of this study was to define the specific contribution of NOX4 NADPH oxidase, which we previously reported as a key CB-ECFC regulator, to hypoxia-induced dysfunction and its potential as a therapeutic target. CB-ECFCs exposed to experimental hypoxia demonstrated downregulation of NOX4-mediated reactive oxygen species (ROS) signalling linked with a reduced tube formation, which was partially restored by NOX4 plasmid overexpression. siRNA knockdown of placenta-specific 8 (PLAC8), identified by microarray analysis as an upstream regulator of NOX4 in hypoxic versus normoxic CB-ECFCs, enhanced tube formation, NOX4 expression and hydrogen peroxide generation, and induced several key transcription factors associated with downstream Nrf2 signalling. Taken together, these findings indicated that activation of the PLAC8-NOX4 signalling axis improved CB-ECFC angiogenic functions in experimental hypoxia, highlighting this pathway as a potential target for protecting therapeutic cells against the ischaemic cardiovascular disease microenvironment.

Rhein alleviates advanced glycation end products (AGEs)-induced inflammatory injury of diabetic cardiomyopathy in vitro and in vivo models

In diabetic patients, diabetic cardiomyopathy (DCM) is one of the most common causes of death. The inflammatory response is essential in the pathogenesis of DCM. Rhein, an anthraquinone compound, is extracted from the herb rhubarb, demonstrating various biological activities. However, it is unclear whether rhein has an anti-inflammatory effect in treating DCM. In our research, we investigated the anti-inflammatory properties as well as its possible mechanism. According to the findings in vitro, rhein could to exert an anti-inflammatory effect by reducing the production of NO, TNF-α, PGE2, iNOS, and COX-2 in RAW264.7 cells that had been stimulated with advanced glycosylation end products (AGEs). In addition, rhein alleviated H9C2 cells inflammation injury stimulated by AGEs/macrophage conditioned medium (CM). In vivo have depicted that continuous gavage of rhein could improve cardiac function and pathological changes. Moreover, it could inhibit the accumulation of AGEs and infiltration of inflammatory factors inside the heart of rats having DCM. Mechanism study showed rhein could suppress IKKβ and IκB phosphorylation via down-regulating TRAF6 expression to inhibit NF-κB pathway in AGEs/CM-induced H9C2 cells. Moreover, the anti-inflammation effect of rhein was realized through down-regulation phosphorylation of JNK MAPK. Furthermore, we found JNK MAPK could crosstalk with NF-κB pathway by regulating IκB phosphorylation without affecting IKKβ activity. And hence, the protective mechanism of rhein may involve the inhibiting of the TRAF6-NF/κB pathway, the JNK MAPK pathway, and the crosstalk between the two pathways. These results suggested that rhein may be a promising drug candidate in anti-inflammation and inflammation-related DCM therapy.

β-Caryophyllene, a Dietary Phytocannabinoid, Alleviates Diabetic Cardiomyopathy in Mice by Inhibiting Oxidative Stress and Inflammation Activating Cannabinoid Type-2 Receptors

Diabetes mellitus (DM) and its associated complications are considered one of the major health risks globally. Among numerous complications, diabetic cardiomyopathy (DCM) is characterized by increased accumulation of lipids and reduced glucose utilization following abnormal lipid metabolism in the myocardium along with oxidative stress, myocardial fibrosis, and inflammation that eventually result in cardiac dysfunction. The abnormal metabolism of lipids plays a fundamental role in cardiac lipotoxicity following the occurrence and development of DCM. Recently, it has been revealed that cannabinoid type-2 (CB2) receptors, an essential component of the endocannabinoid system, play a crucial role in the pathogenesis of obesity, hyperlipidemia, and DM. Provided the role of CB2R in regulating the glucolipid metabolic dysfunction and its antioxidant as well as anti-inflammatory activities, we carried out the current study to investigate the protective effects of a selective CB2R agonist, β-caryophyllene (BCP), a natural dietary cannabinoid in the murine model of DCM and elucidated the underlying pharmacological and molecular mechanisms. Mice were fed a high-fat diet for 4 weeks followed by a single intraperitoneal injection of streptozotocin (100 mg/kg) to induce the model of DCM. BCP (50 mg/kg body weight) was given orally for 12 weeks. AM630, a CB2R antagonist, was given 30 min before BCP treatment to demonstrate the CB2R-dependent mechanism of BCP. DCM mice exhibited hyperglycemia, increased serum lactate dehydrogenase, impaired cardiac function, and hypertrophy. In addition, DCM mice showed alternations in serum lipids and increased oxidative stress concomitant to reduced antioxidant defenses and enhanced cardiac lipid accumulation in the diabetic heart. DCM mice also exhibited activation of TLR4/NF-κB/MAPK signaling and triggered the production of inflammatory cytokines and inflammatory enzyme mediators. However, treatment with BCP exerted remarkable protective effects by favorable modulation of the biochemical and molecular parameters, which were altered in DCM mice. Interestingly, pretreatment with AM630 abrogated the protective effects of BCP in DCM mice. Taken together, the findings of the present study demonstrate that BCP possesses the capability to mitigate the progression of DCM by inhibition of lipotoxicity-mediated cardiac oxidative stress and inflammation and favorable modulation of TLR4/NF-κB/MAPK signaling pathways mediating the CB2R-dependent mechanism.

SIRT6: A potential therapeutic target for diabetic cardiomyopathy

The abnormal lipid metabolism in diabetic cardiomyopathy can cause myocardial mitochondrial dysfunction, lipotoxicity, abnormal death of myocardial cells, and myocardial remodeling. Mitochondrial homeostasis and normal lipid metabolism can effectively slow down the development of diabetic cardiomyopathy. Recent studies have shown that SIRT6 may play an important role in the pathological changes of diabetic cardiomyopathy such as myocardial cell death, myocardial hypertrophy, and myocardial fibrosis by regulating mitochondrial oxidative stress and glucose and lipid metabolism. Therefore, understanding the function of SIRT6 and its role in the pathogenesis of diabetic cardiomyopathy is of great significance for exploring and developing new targets and drugs for the treatment of diabetic cardiomyopathy. This article reviews the latest findings of SIRT6 in the pathogenesis of diabetic cardiomyopathy, focusing on the regulation of mitochondria and lipid metabolism by SIRT6 to explore potential clinical treatments.

Iron accumulation and lipid peroxidation: implication of ferroptosis in diabetic cardiomyopathy

Diabetic cardiomyopathy (DC) is a serious heart disease caused by diabetes. It is unrelated to hypertension and coronary artery disease and can lead to heart insufficiency, heart failure and even death. Currently, the pathogenesis of DC is unclear, and clinical intervention is mainly symptomatic therapy and lacks effective intervention objectives. Iron overdose mediated cell death, also known as ferroptosis, is widely present in the physiological and pathological processes of diabetes and DC. Iron is a key trace element in the human body, regulating the metabolism of glucose and lipids, oxidative stress and inflammation, and other biological processes. Excessive iron accumulation can lead to the imbalance of the antioxidant system in DC and activate and aggravate pathological processes such as excessive autophagy and mitochondrial dysfunction, resulting in a chain reaction and accelerating myocardial and microvascular damage. In-depth understanding of the regulating mechanisms of iron metabolism and ferroptosis in cardiovascular vessels can help improve DC management. Therefore, in this review, we summarize the relationship between ferroptosis and the pathogenesis of DC, as well as potential intervention targets, and discuss and analyze the limitations and future development prospects of these targets.

Metabolic Syndrome and Cardiac Remodeling Due to Mitochondrial Oxidative Stress Involving Gliflozins and Sirtuins

PURPOSE OF REVIEW

To address the mechanistic pathways focusing on mitochondria dysfunction, oxidative stress, sirtuins imbalance, and other contributors in patient with metabolic syndrome and cardiovascular disease. Sodium glucose co-transporter type 2 (SGLT-2) inhibitors deeply influence these mechanisms. Recent randomized clinical trials have shown impressive results in improving cardiac function and reducing cardiovascular and renal events. These unexpected results generate the need to deepen our understanding of the molecular mechanisms able to generate these effects to help explain such significant clinical outcomes.

RECENT FINDINGS

Cardiovascular disease is highly prevalent among individuals with metabolic syndrome and diabetes. Furthermore, mitochondrial dysfunction is a principal player in its development and persistence, including the consequent cardiac remodeling and events. Another central protagonist is the renin-angiotensin system; the high angiotensin II (Ang II) activity fuel oxidative stress and local inflammatory responses. Additionally, sirtuins decline plays a pivotal role in the process; they enhance oxidative stress by regulating adaptive responses to the cellular environment and interacting with Ang II in many circumstances, including cardiac and vascular remodeling, inflammation, and fibrosis. Fasting and lower mitochondrial energy generation are conditions that substantially reduce most of the mentioned cardiometabolic syndrome disarrangements. In addition, it increases sirtuins levels, and adenosine monophosphate-activated protein kinase (AMPK) signaling stimulates hypoxia-inducible factor-1β (HIF-1 beta) and favors ketosis. All these effects favor autophagy and mitophagy, clean the cardiac cells with damaged organelles, and reduce oxidative stress and inflammatory response, giving cardiac tissue protection. In this sense, SGLT-2 inhibitors enhance the level of at least four sirtuins, some located in the mitochondria. Moreover, late evidence shows that SLGT-2 inhibitors mimic this protective process, improving mitochondria function, oxidative stress, and inflammation. Considering the previously described protection at the cardiovascular level is necessary to go deeper in the knowledge of the effects of SGLT-2 inhibitors on the mitochondria function. Various of the protective effects these drugs clearly had shown in the trials, and we briefly describe it could depend on sirtuins enhance activity, oxidative stress reduction, inflammatory process attenuation, less interstitial fibrosis, and a consequent better cardiac function. This information could encourage investigating new therapeutic strategies for metabolic syndrome, diabetes, heart and renal failure, and other diseases.

Sodium Glucose Cotransporter 2 (SGLT2) Inhibitor Ameliorate Metabolic Disorder and Obesity Induced Cardiomyocyte Injury and Mitochondrial Remodeling

Sodium-glucose transporter 2 inhibitors (SGLT2is) exert significant cardiovascular and heart failure benefits in type 2 diabetes mellitus (DM) patients and can help reduce cardiac arrhythmia incidence in clinical practice. However, its effect on regulating cardiomyocyte mitochondria remain unclear. To evaluate its effect on myocardial mitochondria, C57BL/6J mice were divided into four groups, including: (1) control, (2) high fat diet (HFD)-induced metabolic disorder and obesity (MDO), (3) MDO with empagliflozin (EMPA) treatment, and (4) MDO with glibenclamide (GLI) treatment. All mice were sacrificed after 16 weeks of feeding and the epicardial fat secretome was collected. H9c2 cells were treated with the different secretomes for 18 h. ROS production, Ca2+ distribution, and associated proteins expression in mitochondria were investigated to reveal the underlying mechanisms of SGLT2is on cardiomyocytes. We found that lipotoxicity, mitochondrial ROS production, mitochondrial Ca2+ overload, and the levels of the associated protein, SOD1, were significantly lower in the EMPA group than in the MDO group, accompanied with increased ATP production in the EMPA-treated group. The expression of mfn2, SIRT1, and SERCA were also found to be lower after EMPA-secretome treatment. EMPA-induced epicardial fat secretome in mice preserved a better cardiomyocyte mitochondrial biogenesis function than the MDO group. In addition to reducing ROS production in mitochondria, it also ameliorated mitochondrial Ca2+ overload caused by MDO-secretome. These findings provide evidence and potential mechanisms for the benefit of SGLT2i in heart failure and arrhythmias.

New Insights into the Role of Ferroptosis in Cardiovascular Diseases

Cardiovascular diseases (CVDs) are the principal cause of disease burden and death worldwide. Ferroptosis is a new form of regulated cell death mainly characterized by altered iron metabolism, increased polyunsaturated fatty acid peroxidation by reactive oxygen species, depletion of glutathione and inactivation of glutathione peroxidase 4. Recently, a series of studies have indicated that ferroptosis is involved in the death of cardiac and vascular cells and has a key impact on the mechanisms leading to CVDs such as ischemic heart disease, ischemia/reperfusion injury, cardiomyopathies, and heart failure. In this article, we reviewed the molecular mechanism of ferroptosis and the current understanding of the pathophysiological role of ferroptosis in ischemic heart disease and in some cardiomyopathies. Moreover, the comprehension of the machinery governing ferroptosis in vascular cells and cardiomyocytes may provide new insights into preventive and therapeutic strategies in CVDs.

Ferroptosis, necroptosis and cuproptosis: Novel forms of regulated cell death in diabetic cardiomyopathy

Diabetes is a common chronic metabolic disease, and its incidence continues to increase year after year. Diabetic patients mainly die from various complications, with the most common being diabetic cardiomyopathy. However, the detection rate of diabetic cardiomyopathy is low in clinical practice, and targeted treatment is lacking. Recently, a large number of studies have confirmed that myocardial cell death in diabetic cardiomyopathy involves pyroptosis, apoptosis, necrosis, ferroptosis, necroptosis, cuproptosis, cellular burial, and other processes. Most importantly, numerous animal studies have shown that the onset and progression of diabetic cardiomyopathy can be mitigated by inhibiting these regulatory cell death processes, such as by utilizing inhibitors, chelators, or genetic manipulation. Therefore, we review the role of ferroptosis, necroptosis, and cuproptosis, three novel forms of cell death in diabetic cardiomyopathy, searching for possible targets, and analyzing the corresponding therapeutic approaches to these targets.

Astragaloside IV attenuates myocardial dysfunction in diabetic cardiomyopathy rats through downregulation of CD36-mediated ferroptosis

Diabetic cardiomyopathy (DCM), one of the major complications of type 2 diabetes, is a leading cause of heart failure and death in advanced diabetes. Although there is an association between DCM and ferroptosis in cardiomyocytes, the internal mechanism of ferroptosis leading to DCM development remains unknown. CD36 is a key molecule in lipid metabolism that mediates ferroptosis. Astragaloside IV (AS-IV) confers various pharmacological effects such as antioxidant, anti-inflammatory, and immunomodulatory. In this study, we demonstrated that AS-IV was able to recover the dysfunction of DCM. In vivo experiments showed that AS-IV ameliorated myocardial injury and improved contractile function, attenuated lipid deposition, and decreased the expression level of CD36 and ferroptosis-related factors in DCM rats. In vitro experiments showed that AS-IV decreased CD36 expression and inhibited lipid accumulation and ferroptosis in PA-induced cardiomyocytes. The results demonstrated that AS-IV decreased cardiomyocyte injury and myocardial dysfunction by inhibiting ferroptosis mediated by CD36 in DCM rats. Therefore, AS-IV regulated the lipid metabolism of cardiomyocytes and inhibited cellular ferroptosis, which may have potential clinical value in DCM treatment.

Reactive oxygen species and ovarian diseases: Antioxidant strategies

Reactive oxygen species (ROS) are mainly produced in mitochondria and are involved in various physiological activities of the ovary through signaling and are critical for regulating the ovarian cycle. Notably, the imbalance between ROS generation and the antioxidant defense system contributes to the development of ovarian diseases. These contradictory effects have critical implications for potential antioxidant strategies that aim to scavenge excessive ROS. However, much remains to be learned about how ROS causes various ovarian diseases to the application of antioxidant therapy for ovarian diseases. Here, we review the mechanisms of ROS generation and maintenance of homeostasis in the ovary and its associated physiological effects. Additionally, we have highlighted the pathological mechanisms of ROS in ovarian diseases and potential antioxidant strategies for treatment.

Flavonoids of Haloxylon salicornicum (Rimth) prevent cisplatin-induced acute kidney injury by modulating oxidative stress, inflammation, Nrf2, and SIRT1

Cisplatin (CIS) is an effective chemotherapeutic drug used for the treatment of many types of cancers, but its use is associated with adverse effects. Nephrotoxicity is a serious side effect of CIS and limits its therapeutic utility. Haloxylon salicornicum is a desert shrub used traditionally in the treatment of inflammatory disorders, but neither its flavonoid content nor its protective efficacy against CIS nephrotoxicity has been investigated. In this study, seven flavonoids were isolated from H. salicornicum methanolic extract (HSE) and showed in silico binding affinity with NF-κB, Keap1, and SIRT1. The protective effect of HSE against CIS nephrotoxicity was investigated. Rats received HSE (100, 200, and 400 mg/kg) for 14 days followed by a single injection of CIS. The drug increased Kim-1, BUN, and creatinine and caused multiple histopathological changes. CIS-administered rats showed an increase in renal ROS, MDA, NO, TNF-α, IL-1β, and NF-κB p65. HSE prevented tissue injury, and diminished ROS, NF-κB, and inflammatory mediators. HSE enhanced antioxidants and Bcl-2 and downregulated pro-apoptosis markers. These effects were associated with downregulation of Keap1 and microRNA-34a, and upregulation of SIRT1 and Nrf2/HO-1 signaling. In conclusion, H. salicornicum is rich in flavonoids, and its extract prevented oxidative stress, inflammation, and kidney injury, and modulated Nrf2/HO-1 and SIRT1 signaling in CIS-treated rats.

The efficacy of PDE5 inhibitors in diabetic patients

BACKGROUND

Phosphodiesterase 5 inhibitors (PDE5i), since their introduction in the late 1990s, have proven their efficacy in treating several conditions, predominantly pulmonary hypertension and erectile dysfunction where they remain the first-line therapeutic option. However, in the recent years, growing evidence from both animal and human studies has emerged to suggest the additional benefits of PDE5i in cardiovascular and metabolic disorders. This is of specific interest to the diabetes population where prevalent cardiovascular disease and metabolic dysregulation significantly contribute to the increased morbidity and mortality.

OBJECTIVES

To examine the available data on the non-standard, pleiotropic effects of PDE5i in patients with diabetes mellitus.

MATERIALS AND METHODS

The review of the published background research, preclinical studies and clinical trials.

RESULTS

In human studies, PDE5 inhibition appeared to be associated with reduced cardiovascular mortality and overall improved clinical outcomes in those with established cardiovascular disease. PDE5i were also consistently found to reduce albuminuria in subjects with diabetic nephropathy. Furthermore, animal data suggest a plausible effect of this group of medication on sensory function and neuropathic symptoms in diabetic neuropathy as well as improved wound healing. A decrease in insulin resistance and augmentation of beta cell function seen in preclinical studies has not been consistently demonstrated in human trials.

DISCUSSION AND CONCLUSION

In animal models, PDE5 inhibition appears to decrease oxidative stress and reduce some of the micro- and macrovascular complications associated with diabetes. However, data from human trials are limited and largely inconsistent, highlighting the need for adequately powered, randomised-controlled trials in diabetic cohorts in order to fully assess the benefits of PDE5i in this group of patients.

Role of AIM2 Gene Knockdown Mechanism in Diabetic Cardiomyopathy: an In Vivo and Ex Vivo Study

Chronic hyperglycemia induces reactive oxygen species that have an essential function in tissue injuries in cases of diabetic cardiomyopathy. The mechanism of the absent in melanoma 2 (AIM2)-associated inflammasome response in diabetic cardiomyopathy is unknown. Therefore, this study was performed to investigate the role of AIM2 and its molecular mechanisms. Diabetic rats received 1 × 10⁸ viral injections of 5'-GGTCACCAGTTCCTCAGTT-3' (n = 15) or 5'-TTCTCCGAACGTGTCACGT-3' (negative control group, n = 15). Normal rats (n = 15) and diabetic rats (n = 15) were also included in the experiment. Ex vivo study was performed on primary cardiomyocytes for different concentrations of glucose. AIM2 inhibition did not affect any of the metabolic parameters (p > 0.05 for all). AIM2 protein levels were significantly increased in rats with diabetes mellitus compared with those in the control group (p < 0.0001, q = 32.044). Also, viral injection (sequence: 5'-GGTCACCAGTTCCTCAGTT-3') decreased the diabetes mellitus-induced increase in expression of AIM2 protein levels (p < 0.0001, q = 27.129). Cardiac dysfunctions were reported in rats with diabetes mellitus characterized by several parameters (p < 0.01 for all). The diabetic myocardium of rats was reported to have higher deposits of extracellular matrix compared to the control rats (p < 0.001). These effects were downregulated by viral injection (sequence: 5'-GGTCACCAGTTCCTCAGTT-3'). Ex vivo research revealed that high glucose concentrations significantly increased AIM2 protein expression, reactive oxygen species, and cell death. AIM2 protein in diabetic cardiomyopathy is associated with reactive oxygen species production and cardiomyocyte death.

Identification of diagnostic markers related to oxidative stress and inflammatory response in diabetic kidney disease by machine learning algorithms: Evidence from human transcriptomic data and mouse experiments

INTRODUCTION

Diabetic kidney disease (DKD) is a long-term complication of diabetes and causes renal microvascular disease. It is also one of the main causes of end-stage renal disease (ESRD), which has a complex pathophysiological process. Timely prevention and treatment are of great significance for delaying DKD. This study aimed to use bioinformatics analysis to find key diagnostic markers that could be possible therapeutic targets for DKD.

METHODS

We downloaded DKD datasets from the Gene Expression Omnibus (GEO) database. Overexpression enrichment analysis (ORA) was used to explore the underlying biological processes in DKD. Algorithms such as WGCNA, LASSO, RF, and SVM_RFE were used to screen DKD diagnostic markers. The reliability and practicability of the the diagnostic model were evaluated by the calibration curve, ROC curve, and DCA curve. GSEA analysis and correlation analysis were used to explore the biological processes and significance of candidate markers. Finally, we constructed a mouse model of DKD and diabetes mellitus (DM), and we further verified the reliability of the markers through experiments such as PCR, immunohistochemistry, renal pathological staining, and ELISA.

RESULTS

Biological processes, such as immune activation, T-cell activation, and cell adhesion were found to be enriched in DKD. Based on differentially expressed oxidative stress and inflammatory response-related genes (DEOIGs), we divided DKD patients into C1 and C2 subtypes. Four potential diagnostic markers for DKD, including tenascin C, peroxidasin, tissue inhibitor metalloproteinases 1, and tropomyosin (TNC, PXDN, TIMP1, and TPM1, respectively) were identified using multiple bioinformatics analyses. Further enrichment analysis found that four diagnostic markers were closely related to various immune cells and played an important role in the immune microenvironment of DKD. In addition, the results of the mouse experiment were consistent with the bioinformatics analysis, further confirming the reliability of the four markers.

CONCLUSION

In conclusion, we identified four reliable and potential diagnostic markers through a comprehensive and systematic bioinformatics analysis and experimental validation, which could serve as potential therapeutic targets for DKD. We performed a preliminary examination of the biological processes involved in DKD pathogenesis and provide a novel idea for DKD diagnosis and treatment.

6-Gingerol Alleviates Ferroptosis and Inflammation of Diabetic Cardiomyopathy via the Nrf2/HO-1 Pathway

BACKGROUND

Diabetes mellitus (DM) can induce cardiomyocyte injury and lead to diabetic cardiomyopathy (DCM) which presently has no specific treatments and consequently increase risk of mortality.

OBJECTIVE

To characterize the therapeutic effect of 6-gingerol (6-G) on DCM and identify its potential mechanism.

METHODS

In vivo streptozotocin- (STZ-) induced DM model was established by using a high-fat diet and STZ, followed by low-dose (25 mg/kg) and high-dose (75 mg/kg) 6-G intervention. For an in vitro DCM model, H9c2 rat cardiomyoblast cells were stimulated with high glucose (glucose = 33 mM) and palmitic acid (100 μM) and then treated with 6-G (100 μM). Histological and echocardiographic analyses were used to assess the effect of 6-G on cardiac structure and function in DCM. Western blotting, ELISA, and real-time qPCR were used to assess the expression of ferroptosis, inflammation, and the Nrf2/HO-1 pathway-related proteins and RNAs. Protein expression of collagen I and collagen III was assessed by immunohistochemistry, and kits were used to assay SOD, MDA, and iron levels.

RESULTS

The results showed that 6-G decreased cardiac injury in both mouse and cell models of DCM. The cardiomyocyte hypertrophy and interstitial fibrosis were attenuated by 6-G treatment in vivo and resulted in an improved heart function. 6-G inhibited the expression of ferroptosis-related protein FACL4 and the content of iron and enhanced the expression of anti-ferroptosis-related protein GPX4. In addition, 6-G also diminished the secretion of inflammatory cytokines, including IL-1β, IL-6, and TNF-α. 6-G treatment activated the Nrf2/HO-1 pathway, enhanced antioxidative stress capacity proved by increased activity of SOD, and decreased MDA production. Compared with in vivo, 6-G treatment of H9c2 cells treated with high glucose and palmitic acid could produce a similar effect.

CONCLUSION

These findings suggest that 6-G could protect against DCM by the mechanism of ferroptosis inhibition and inflammation reduction via enhancing the Nrf2/HO-1 pathway.

Energy substrate metabolism and oxidative stress in metabolic cardiomyopathy

Metabolic cardiomyopathy is an emerging cause of heart failure in patients with obesity, insulin resistance, and diabetes. It is characterized by impaired myocardial metabolic flexibility, intramyocardial triglyceride accumulation, and lipotoxic damage in association with structural and functional alterations of the heart, unrelated to hypertension, coronary artery disease, and other cardiovascular diseases. Oxidative stress plays an important role in the development and progression of metabolic cardiomyopathy. Mitochondria are the most significant sources of reactive oxygen species (ROS) in cardiomyocytes. Disturbances in myocardial substrate metabolism induce mitochondrial adaptation and dysfunction, manifested as a mismatch between mitochondrial fatty acid oxidation and the electron transport chain (ETC) activity, which facilitates ROS production within the ETC components. In addition, non-ETC sources of mitochondrial ROS, such as β-oxidation of fatty acids, may also produce a considerable quantity of ROS in metabolic cardiomyopathy. Augmented ROS production in cardiomyocytes can induce a variety of effects, including the programming of myocardial energy substrate metabolism, modulation of metabolic inflammation, redox modification of ion channels and transporters, and cardiomyocyte apoptosis, ultimately leading to the structural and functional alterations of the heart. Based on the above mechanistic views, the present review summarizes the current understanding of the mechanisms underlying metabolic cardiomyopathy, focusing on the role of oxidative stress.

Diabetic cardiomyopathy: a brief summary on lipid toxicity

Diabetes mellitus (DM) is a serious epidemic around the globe, and cardiovascular diseases account for the majority of deaths in patients with DM. Diabetic cardiomyopathy (DCM) is defined as a cardiac dysfunction derived from DM without the presence of coronary artery diseases and hypertension. Patients with either type 1 or type 2 DM are at high risk of developing DCM and even heart failure. Metabolic disorders of obesity and insulin resistance in type 2 diabetic environments result in dyslipidaemia and subsequent lipid-induced toxicity (lipotoxicity) in organs including the heart. Although various mechanisms have been proposed underlying DCM, it remains incompletely understood how lipotoxicity alters cardiac function and how DM induces clinical heart syndrome. With recent progress, we here summarize the latest discoveries on lipid-induced cardiac toxicity in diabetic hearts and discuss the underlying therapies and controversies in clinical DCM.

KLF9 Aggravates Streptozotocin-Induced Diabetic Cardiomyopathy by Inhibiting PPARγ/NRF2 Signalling

AIMS

Krüppel-like Factor 9 (KLF9) is a transcription factor that regulates multiple disease processes. Studies have focused on the role of KLF9 in the redox system. In this study, we aimed to explore the effect of KLF9 on diabetic cardiomyopathy.

METHODS AND RESULTS

Cardiac-specific overexpression or silencing of KLF9 in C57BL/6 J mice was induced with an adeno-associated virus 9 (AAV9) delivery system. Mice were also subjected to streptozotocin injection to establish a diabetic cardiomyopathy model. In addition, neonatal rat cardiomyocytes were used to assess the possible role of KLF9 in vitro by incubation with KLF9 adenovirus or small interfering RNA against KLF9. To clarify the involvement of peroxisome proliferator-activated receptors (PPARγ), mice were subjected to GW9662 injection to inhibit PPARγ. KLF9 was upregulated in the hearts of mice with diabetic cardiomyopathy and in cardiomyocytes. In addition, KLF9 overexpression in the heart deteriorated cardiac function and aggravated hypertrophic fibrosis, the inflammatory response and oxidative stress in mice with diabetic cardiomyopathy. Conversely, cardiac-specific silencing of KLF9 ameliorated cardiac dysfunction and alleviated hypertrophy, fibrosis, the cardiac inflammatory response and oxidative stress. In vitro, KLF9 silencing in cardiomyocytes enhanced inflammatory cytokine release and oxidative stress; KLF9 overexpression increased these detrimental responses. Moreover, KLF9 was found to regulate the transcription of PPARγ, which suppressed the expression and nuclear translocation of nuclear Factor E2-related Factor 2 (NRF2). In mice injected with a PPARγ inhibitor, the protective effects of KLF9 knockdown on diabetic cardiomyopathy were counteracted by GW9662 injection.

CONCLUSIONS

KLF9 aggravates cardiac dysfunction, the inflammatory response and oxidative stress in mice with diabetic cardiomyopathy. KLF9 may become a therapeutic target for diabetic cardiomyopathy.

Therapeutic overexpression of miR-92a-2-5p ameliorated cardiomyocyte oxidative stress injury in the development of diabetic cardiomyopathy

Background

Diabetic cardiomyopathy (DCM) results from pathological changes in cardiac structure and function caused by diabetes. Excessive oxidative stress is an important feature of DCM pathogenesis. MicroRNAs (miRNAs) are key regulators of oxidative stress in the cardiovascular system. In the present study, we screened for the expression of oxidative stress-responsive miRNAs in the development of DCM. Furthermore, we aimed to explore the mechanism and therapeutic potential of miR-92a-2-5p in preventing diabetes-induced myocardial damage.

Methods

An experimental type 2 diabetic (T2DM) rat model was induced using a high-fat diet and low-dose streptozotocin (30 mg/kg). Oxidative stress injury in cardiomyocytes was induced by high glucose (33 mmol/L). Oxidative stress-responsive miRNAs were screened by quantitative real-time PCR. Intervention with miR-92a-2-5p was accomplished by tail vein injection of agomiR in vivo or adenovirus transfection in vitro.

Results

The expression of miR-92a-2-5p in the heart tissues was significantly decreased in the T2DM group. Decreased miR-92a-2-5p expression was also detected in high glucose-stimulated cardiomyocytes. Overexpression of miR-92a-2-5p attenuated cardiomyocyte oxidative stress injury, as demonstrated by increased glutathione level, and reduced reactive oxygen species accumulation, malondialdehyde and apoptosis levels. MAPK interacting serine/threonine kinase 2 (MKNK2) was verified as a novel target of miR-92a-2-5p. Overexpression of miR-92a-2-5p in cardiomyocytes significantly inhibited MKNK2 expression, leading to decreased phosphorylation of p38-MAPK signaling, which, in turn, ameliorated cardiomyocyte oxidative stress injury. Additionally, diabetes-induced myocardial damage was significantly alleviated by the injection of miR-92a-2-5p agomiR, which manifested as a significant improvement in myocardial remodeling and function.

Conclusions

miR-92a-2-5p plays an important role in cardiac oxidative stress, and may serve as a therapeutic target in DCM.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s11658-022-00379-9.

NLRP3 Inflammasome/Pyroptosis: A Key Driving Force in Diabetic Cardiomyopathy

Diabetic cardiomyopathy (DCM), a serious diabetic complication, is a kind of low-grade inflammatory cardiovascular disorder. Due to the high risk of morbidity and mortality, DCM has demanded the attention of medical researchers worldwide. The pathophysiological nature of DCM is intricate, and the genesis and development of which are a consequence of the coaction of many factors. However, the exact pathogenesis mechanism of DCM remains unclear. Pyroptosis is a newly identified programmed cell death (PCD) that is directly related to gasdermin D(GSDMD). It is characterized by pore formation on the cell plasma membrane, the release of inflammatory mediators, and cell lysis. The initiation of pyroptosis is closely correlated with NOD-like receptor 3 (NLRP3) activation, which activates caspase-1 and promotes the cleaving of GSDMD. In addition to adjusting the host’s immune defense, NLRP3 inflammasome/pyroptosis plays a critical role in controlling the systemic inflammatory response. Recent evidence has indicated that NLRP3 inflammasome/pyroptosis has a strong link with DCM. Targeting the activation of NLRP3 inflammasome or pyroptosis may be a hopeful therapeutic strategy for DCM. The focus of this review is to summarize the relevant mechanisms of pyroptosis and the relative contributions in DCM, highlighting the potential therapeutic targets in this field.

β-Lapachone, an NQO1 activator, alleviates diabetic cardiomyopathy by regulating antioxidant ability and mitochondrial function

BACKGROUND

Diabetic cardiomyopathy (DC) is one of the major lethal complications in patients with diabetes mellitus (DM); however, no specific strategy for preventing or treating DC has been identified.

PURPOSE

This study aimed to investigate the effects of β-lapachone (Lap), a natural compound that increases antioxidant activity in various tissues, on DC and explore the underlying mechanisms.

STUDY DESIGN AND METHODS

As an in vivo model, C57BL/6 mice were fed with the high-fat diet (HF) for 10 weeks to induce type 2 DM. Mice were fed Lap with the HF or after 5 weeks of HF treatment to investigate the protective effects of Lap against DC.

RESULTS

In the two in vivo models, Lap decreased heart weight, increased heart function, reduced oxidative stress, and elevated mitochondrial content under the HF. In the in vitro model, palmitic acid (PA) was used to mimic the effects of an HF on the differentiated-cardiomyoblast cell line H9c2. The results demonstrated that Lap reduced PA-induced ROS production by increasing the expression of antioxidant regulators and enzymes, inhibiting inflammation, increasing mitochondrial activity, and thus reducing cell damage. Via the use of specific inhibitors and siRNA, the protective effects of Lap were determined to be mediated mainly by NQO1, Sirt1 and mitochondrial activity.

CONCLUSION

Heart damage in DM is usually caused by excessive oxidative stress. This study showed that Lap can protect the heart from DC by upregulating antioxidant ability and mitochondrial activity in cardiomyocytes. Lap has the potential to serve as a novel therapeutic agent for both the prevention and treatment of DC.

Exercise Augments the Effect of SGLT2 Inhibitor Dapagliflozin on Experimentally Induced Diabetic Cardiomyopathy, Possible Underlying Mechanisms

One of the most prevalent cardiovascular problems linked with type 2 diabetes mellitus (T2DM) is diabetic cardiomyopathy (DCM). DCM is associated with myocardial oxidative stress, inflammation, apoptosis, suppressed autophagy, extracellular matrix remodeling, and fibrosis. The current study aims to investigate the protective effect of sodium-glucose transport 2 inhibitor (SGLT2i) dapagliflozin and/or exercise on DCM. Thirty adult male Sprague Dawley rats are used. T2DM is induced by a 6-week high-fat diet (HFD) followed by a single intraperitoneal (IP) injection of 35 mg/kg streptozotocin (STZ). Rats are divided into five groups, control, diabetic (DM), DM + swimming, DM + dapagliflozin, and DM + dapagliflozin and swimming. Serum glucose, insulin, insulin resistance (HOMA-IR), and cardiac enzymes (CK-MB and lactate dehydrogenase (LDH) are measured. Heart specimens are used for evaluation of cellular oxidative stress markers malondialdehyde (MDA), antioxidant enzymes, glutathione (GSH), and catalase (CAT), as well as mRNA expression of TGF-β, MMP9, IL-1β, and TNF-α. Stained sections with haematoxylin and eosin (H & E) and Masson trichrome are used for histopathological evaluation and detection of fibrosis, respectively. Immunohistochemical staining for apoptosis (caspase-3), and autophagy (LC3) are also carried out. The combinations of SGLT2i and exercise exhibited the most significant cardioprotective effect. It improved diabetic-induced histopathological alterations in the myocardium and attenuated the elevation of serum blood glucose, CK-MB, LDH, myocardial MDA, and mRNA expression of TNF-α, IL-1β, TGF-β, MMP9, and the immune expression of caspase-3. Moreover, this combination increased the serum insulin, myocardial antioxidants GSH and CAT, and increase the immune expression of the LC-3. In conclusion, a combination of SGLT2i and exercise exerted a better antioxidant, anti-inflammatory, and antifibrotic effect in DCM. Moreover, the combination enhances the autophagic capacity of the heart.

Protective effects and possible mechanism of 6-gingerol against arsenic trioxide-induced nephrotoxicity based on network pharmacological analysis and experimental validation

BACKGROUND AND OBJECTIVE

Nephrotoxicity induced by the chemotherapeutic drug arsenic trioxide (ATO) is often overlooked, and the underlying mechanisms remain poorly understood. Based on network pharmacology and experimental validation, this study investigates the protection of 6-gingerol (6G) against ATO-induced nephrotoxicity and the potential mechanisms.

METHODS

We screened and collected 6G and disease-related targets and then imported the interaction targets into a String database to construct protein-protein interaction (PPI) networks. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed using the Database for Annotation, Visualization and Integrated Discovery (DAVID). Mice were injected intraperitoneally with ATO (5 mg/kg) for seven days to induce nephrotoxicity, and then the histological morphology of the kidneys, biochemical indices of serum and tissues, and associated protein expressions were observed.

RESULTS

The network pharmacology results revealed that the effects of 6G against nephrotoxicity are closely related to apoptosis, and the MAPKs pathway was screened for validation. In animal experiments, 6G improved the histopathological morphology of the kidneys, reduced the levels of renal function markers, enhanced antioxidant activity, and decreased the levels of inflammation. Furthermore, 6G reduced apoptotic cells in kidney tissues, decreased the levels of Bax and c-Caspase-3, and increased the level of Bcl-2. The results of immunohistochemistry and western blotting revealed that 6G significantly inhibited the expressions of p-p38, p-ERK, and p-JNK.

CONCLUSION

The results comprehensively demonstrate the protective effects of 6G against ATO-induced nephrotoxicity. The effects are related to anti-oxidant, anti-inflammatory, and anti-apoptotic properties, possibly through inhibition of the MAPKs pathway.

A novel role of Nano selenium and sildenafil on streptozotocin-induced diabetic nephropathy in rats by modulation of inflammatory, oxidative, and apoptotic pathways

AIMS

The present study aimed to investigate the effect of nano selenium, sildenafil, and their combination on inflammation, oxidative stress, and apoptosis in streptozotocin-induced diabetic nephropathy in rats. Herein, a new anti-inflammatory pathway for sildenafil as a high-mobility group box (HMGB1) inhibitor was proposed using the molecular docking technique.

MATERIALS AND METHODS

Rats were divided into 7 groups: normal control, control nano selenium, control sildenafil, control diabetic, diabetic+ nano selenium, diabetic+ sildenafil, diabetic+ nano selenium+ sildenafil. The effects of drugs were evaluated by measuring serum urea, creatinine, lactate dehydrogenase (LDH), levels of tumor necrosis factor-alpha (TNF-α), Interleukin 1 beta (IL-1β), HMGB1, receptor advanced glycation end product (RAGE), malondialdehyde (MDA), thioredoxin reductase (TrxR) by biochemical assays, nuclear factor-kappa b (NF-κB), toll-like receptor (TLR4) by immunohistochemistry, gene expressions of caspase 3 and monocyte chemoattractant protein (MCP-1) besides histopathological investigations of renal cells.

KEY FINDINGS

Results showed beneficial effects of 8 weeks of treatment by nano selenium and sildenafil supported by improvement in kidney function, histopathological changes, and reduction in all of these parameters. These results supported molecular docking that indicated sildenafil had a high binding score and interactions with the HMGB1 receptor.

SIGNIFICANCE

The current study demonstrated a renoprotective effect of nano‑selenium and sildenafil by interfering at multiple pathways, especially the HMGB1/NF-κB signaling pathway.

Roles of Ferroptosis in Cardiovascular Diseases

Ferroptosis is an iron-dependent regulated cell death characterized by lipid peroxidation and iron overload, which is different from other types of programmed cell death, including apoptosis, necroptosis, autophagy, and pyroptosis. Over the past years, emerging studies have shown a close relation between ferroptosis and various cardiovascular diseases such as atherosclerosis, acute myocardial infarction, ischemia/reperfusion injury, cardiomyopathy, and heart failure. Herein, we will review the contributions of ferroptosis to multiple cardiovascular diseases and the related targets. Further, we discuss the potential ferroptosis-targeting strategies for treating different cardiovascular diseases.

Mitochondria-Mediated Cardiovascular Benefits of Sodium-Glucose Co-Transporter 2 Inhibitors

Several recent cardiovascular trials of SGLT 2 (sodium-glucose cotransporter 2) inhibitors revealed that they could reduce adverse cardiovascular events in patients with T2DM (type 2 diabetes mellitus). However, the exact molecular mechanism underlying the beneficial effects that SGLT2 inhibitors have on the cardiovascular system is still unknown. In this review, we focus on the molecular mechanisms of the mitochondria-mediated beneficial effects of SGLT2 inhibitors on the cardiovascular system. The application of SGLT2 inhibitors ameliorates mitochondrial dysfunction, dynamics, bioenergetics, and ion homeostasis and reduces the production of mitochondrial reactive oxygen species, which results in cardioprotective effects. Herein, we present a comprehensive overview of the impact of SGLT2 inhibitors on mitochondria and highlight the potential application of these medications to treat both T2DM and cardiovascular diseases.

Antioxidant Cardioprotection against Reperfusion Injury: Potential Therapeutic Roles of Resveratrol and Quercetin

Ischemia-reperfusion myocardial damage is a paradoxical tissue injury occurring during percutaneous coronary intervention (PCI) in acute myocardial infarction (AMI) patients. Although this damage could account for up to 50% of the final infarct size, there has been no available pharmacological treatment until now. Oxidative stress contributes to the underlying production mechanism, exerting the most marked injury during the early onset of reperfusion. So far, antioxidants have been shown to protect the AMI patients undergoing PCI to mitigate these detrimental effects; however, no clinical trials to date have shown any significant infarct size reduction. Therefore, it is worthwhile to consider multitarget antioxidant therapies targeting multifactorial AMI. Indeed, this clinical setting involves injurious effects derived from oxygen deprivation, intracellular pH changes and increased concentration of cytosolic Ca²⁺ and reactive oxygen species, among others. Thus, we will review a brief overview of the pathological cascades involved in ischemia-reperfusion injury and the potential therapeutic effects based on preclinical studies involving a combination of antioxidants, with particular reference to resveratrol and quercetin, which could contribute to cardioprotection against ischemia-reperfusion injury in myocardial tissue. We will also highlight the upcoming perspectives of these antioxidants for designing future studies.

Molecular Correlates of Early Onset of Diabetic Cardiomyopathy: Possible Therapeutic Targets

Diabetes mellitus (DM) is associated with mitochondrial dysfunction and oxidative stress that can lead to diabetic cardiomyopathy (DCM), which can often remain undetected until late stages of the disease. However, myocardial injury occurs before the onset of measurable cardiac dysfunction, although its molecular correlates are poorly understood. In this study, we made a DM rat induced by a high-fat diet combined with low and high doses of streptozotocin (STZ) to emulate pre and early DCM. RNA-sequencing analysis of ventricular tissue revealed a differential transcriptome profile and abnormal activation of pathways involved in fatty acid metabolism, oxidative phosphorylation, cardiac structure and function, insulin resistance, calcium signalling, apoptosis, and TNF signalling. Moreover, using high glucose-treated human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CM), we recapitulated the cardiac cellular phenotype of DM and identified several molecular correlates that may promote the development of DCM. In conclusion, we have developed an experimental framework to target pathways underlying the progression of DCM.

Heart Failure and Drug Therapies: A Metabolic Review

Cardiovascular disease is the leading cause of mortality globally with at least 26 million people worldwide living with heart failure (HF). Metabolism has been an active area of investigation in the setting of HF since the heart demands a high rate of ATP turnover to maintain homeostasis. With the advent of -omic technologies, specifically metabolomics and lipidomics, HF pathologies have been better characterized with unbiased and holistic approaches. These techniques have identified novel pathways in our understanding of progression of HF and potential points of intervention. Furthermore, sodium-glucose transport protein 2 inhibitors, a drug that has changed the dogma of HF treatment, has one of the strongest types of evidence for a potential metabolic mechanism of action. This review will highlight cardiac metabolism in both the healthy and failing heart and then discuss the metabolic effects of heart failure drugs.

Supplementation with a Cocoa-Carob Blend, Alone or in Combination with Metformin, Attenuates Diabetic Cardiomyopathy, Cardiac Oxidative Stress and Inflammation in Zucker Diabetic Rats

Diabetic cardiomyopathy (DCM) is one of the main causes of mortality among diabetic patients, with oxidative stress and inflammation major contributors to its development. Dietary flavonoids show strong antioxidant and anti-inflammatory activities, although their potential additive outcomes in combination with antidiabetic drugs have been scarcely explored. The present study investigates the cardioprotective effects of a cocoa–carob blend (CCB) diet, rich in flavonoids, alone or in combination with metformin, in the development of DCM. Zucker diabetic fatty rats (ZDF) were fed with a CCB rich-diet or a control diet, with or without metformin for 12 weeks. Glucose homeostasis, cardiac structure and function, and oxidative and inflammatory biomarkers were analysed. CCB improved glucose homeostasis, and mitigated cardiac dysfunction, hypertrophy, and fibrosis in ZDF rats. Mechanistically, CCB counteracted oxidative stress in diabetic hearts by down-regulating NADPH oxidases, reducing reactive oxygen species (ROS) generation and modulating the sirtuin-1 (SIRT1)/ nuclear factor E2-related factor 2 (Nrf2) signalling pathway, overall improving antioxidant defence. Moreover, CCB suppressed inflammatory and fibrotic reactions by inhibiting nuclear factor kappa B (NFκB) and pro-inflammatory and pro-fibrotic cytokines. Noteworthy, several of these effects were further improved in combination with metformin. Our results demonstrate that CCB strongly prevents the cardiac remodelling and dysfunction observed in diabetic animals, highlighting its potential, alone or in adjuvant therapy, for treating DCM.

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

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

Ferroptosis is essential for diabetic cardiomyopathy and is prevented by sulforaphane via AMPK/NRF2 pathways

Herein, we define the role of ferroptosis in the pathogenesis of diabetic cardiomyopathy (DCM) by examining the expression of key regulators of ferroptosis in mice with DCM and a new ex vivo DCM model. Advanced glycation end-products (AGEs), an important pathogenic factor of DCM, were found to induce ferroptosis in engineered cardiac tissues (ECTs), as reflected through increased levels of Ptgs2 and lipid peroxides and decreased ferritin and SLC7A11 levels. Typical morphological changes of ferroptosis in cardiomyocytes were observed using transmission electron microscopy. Inhibition of ferroptosis with ferrostatin-1 and deferoxamine prevented AGE-induced ECT remodeling and dysfunction. Ferroptosis was also evidenced in the heart of type 2 diabetic mice with DCM. Inhibition of ferroptosis by liproxstatin-1 prevented the development of diastolic dysfunction at 3 months after the onset of diabetes. Nuclear factor erythroid 2-related factor 2 (NRF2) activated by sulforaphane inhibited cardiac cell ferroptosis in both AGE-treated ECTs and hearts of DCM mice by upregulating ferritin and SLC7A11 levels. The protective effect of sulforaphane on ferroptosis was AMP-activated protein kinase (AMPK)-dependent. These findings suggest that ferroptosis plays an essential role in the pathogenesis of DCM; sulforaphane prevents ferroptosis and associated pathogenesis via AMPK-mediated NRF2 activation. This suggests a feasible therapeutic approach with sulforaphane to clinically prevent ferroptosis and DCM.

Symbiotic Algae-Bacteria Dressing for Producing Hydrogen to Accelerate Diabetic Wound Healing

Oxidative stress induced by hyperglycemia or chronic inflammation can limit diabetic wound healing, resulting in diabetic foot ulcers. Hydrogen has the potential to act as an antioxidant and scavenge reactive oxygen species, thereby attenuating inflammation in these chronic wounds. However, most of the reported H₂ delivery systems for wound healing, including hydrogen gas, hydrogen-rich water, and hydrogen-rich saline, are very short-lived for the low solubility of hydrogen gas. Here, we introduce a hydrogen-producing hydrogel made of living Chlorella and bacteria within a cell-impermeable casing that can continuously produce hydrogen for 60 h. This microbe-hydrogel system can selectively reduce highly toxic •OH and ONOO^- species and reduce inflammation. Additional experiments indicated that the microbe-hydrogel dressing could promote cell proliferation and diabetic wound healing by almost 50% at day 3. The symbiotic algae-bacteria hydrogel has excellent biocompatibility and reactive oxygen species scavenging features, indicating it has great promise for clinical use.