Sulforaphane prevents the development of cardiomyopathy in type 2 diabetic mice probably by reversing oxidative stress-induced inhibition of LKB1/AMPK pathway

Sulforaphane enhanced muscle growth by promoting lipid oxidation through modulating key signaling pathways

Sulforaphane (SFN) has shown diverse effects on human health and diseases. SFN was administered daily to C57BL/6J mice at doses of 1 mg/kg (SFN1) and 3 mg/kg (SFN3) for 8 weeks. Both doses of SFN accelerated body weight increment. The cross-sectional area and diameter of Longissimus dorsi (LD) muscle fibers were enlarged in SFN3 group. Triglyceride (TG) and total cholesterol (TC) levels in LD muscle were decreased in SFN groups. RNA sequencing results revealed that 2455 and 2318 differentially expressed genes (DEGs) were found in SFN1 and SFN3 groups, respectively. Based on GO enrichment analysis, 754 and 911 enriched GO terms in the SFN1 and SFN3 groups, respectively. KEGG enrichment analysis shown that one KEGG pathway was enriched in the SFN1 group, while six KEGG pathways were enriched in the SFN3 group. The expressions of nine selected DEGs validated with qRT-PCR were in line with the RNA sequencing data. Furthermore, SFN treatment influenced lipid and protein metabolism related pathways including AMPK signaling, fatty acid metabolism signaling, cholesterol metabolism signalling, PPAR signaling, peroxisome signaling, TGFβ signaling, and mTOR signaling. In summary, SFN elevated muscle fibers size and reduced TG and TC content of in LD muscle by modulating protein and lipid metabolism-related signaling pathways.

Update on clinical and experimental management of diabetic cardiomyopathy: addressing current and future therapy

Diabetic cardiomyopathy (DCM) is a severe secondary complication of type 2 diabetes mellitus (T2DM) that is diagnosed as a heart disease occurring in the absence of any previous cardiovascular pathology in diabetic patients. Although it is still lacking an exact definition as it combines aspects of both pathologies - T2DM and heart failure, more evidence comes forward that declares DCM as one complex disease that should be treated separately. It is the ambiguous pathological phenotype, symptoms or biomarkers that makes DCM hard to diagnose and screen for its early onset. This re-view provides an updated look on the novel advances in DCM diagnosis and treatment in the experimental and clinical settings. Management of patients with DCM proposes a challenge by itself and we aim to help navigate and advice clinicians with early screening and pharmacotherapy of DCM.

Protective effects of sulforaphane against toxic substances and contaminants: A systematic review

BACKGROUND

Sulforaphane (SFN) is a dietary isothiocyanate, derived from glucoraphanin, present in cruciferous vegetables belonging to the Brassica genus. It is a biologically active phytochemical that acts as a nuclear factor erythroid 2-related factor 2 (Nrf2) inducer. Thus, it has been reported to have multiple protective functions including anticancer responses and protection against a toxic agent's action.

PURPOSE

The present work systematically reviewed and synthesised the protective properties of sulforaphane against a toxic agent. This review reveals the mechanism of the action of SFN in each organ or system.

METHODS

The PRISMA guideline was followed in this sequence: researched literature, organised retrieved documents, abstracted relevant information, assessed study quality and bias, synthesised data, and prepared a comprehensive report. Searches were conducted on Science Direct and PubMed using the keywords "Sulforaphane" AND ("protective effects" OR "protection against").

RESULTS

Reports showed that liver and the nervous system are the target organs on which attention was focused, and this might be due to the key role of oxidative stress in liver and neurodegenerative diseases. However, protective activities have also been demonstrated in the lungs, heart, immune system, kidneys, and endocrine system. SFN exerts its protective effects by activating the Nrf2 pathway, which enhances antioxidant defenses and reduces oxidative stress. It also suppresses inflammation by decreasing interleukin production. Moreover, SFN inhibits apoptosis by preventing caspase 3 cleavage and increasing Bcl2 levels. Overall, SFN demonstrates multifaceted mechanisms to counteract the adverse effects of toxic agents.

CONCLUSION

SFN has potential clinical applications as a chemoprotective agent. Nevertheless, more studies are necessary to set the safe doses of SFN in humans.

Sulforaphane prevents diabetes-induced hepatic ferroptosis by activating Nrf2 signaling axis

Recently, we characterized the ferroptotic phenotype in the liver of diabetic mice and revealed nuclear factor (erythroid-derived-2)-related factor 2 (Nrf2) inactivation as an integral part of hepatic injury. Here, we aim to investigate whether sulforaphane, an Nrf2 activator and antioxidant, prevents diabetes-induced hepatic ferroptosis and the mechanisms involved. Male C57BL/6 mice were divided into four groups: control (vehicle-treated), diabetic (streptozotocin-induced; 40 mg/kg, from Days 1 to 5), diabetic sulforaphane-treated (2.5 mg/kg from Days 1 to 42) and non-diabetic sulforaphane-treated group (2.5 mg/kg from Days 1 to 42). Results showed that diabetes-induced inactivation of Nrf2 and decreased expression of its downstream antiferroptotic molecules critical for antioxidative defense (catalase, superoxide dismutases, thioredoxin reductase), iron metabolism (ferritin heavy chain (FTH1), ferroportin 1), glutathione (GSH) synthesis (cystine-glutamate antiporter system, cystathionase, glutamate-cysteine ligase catalitic subunit, glutamate-cysteine ligase modifier subunit, glutathione synthetase), and GSH recycling - glutathione reductase (GR) were reversed/increased by sulforaphane treatment. In addition, we found that the ferroptotic phenotype in diabetic liver is associated with increased ferritinophagy and decreased FTH1 immunopositivity. The antiferroptotic effect of sulforaphane was further evidenced through the increased level of GSH, decreased accumulation of labile iron and lipid peroxides (4-hydroxy-2-nonenal, lipofuscin), decreased ferritinophagy and liver damage (decreased fibrosis, alanine aminotransferase, and aspartate aminotransferase). Finally, diabetes-induced increase in serum glucose and triglyceride level was significantly reduced by sulforaphane. Regardless of the fact that this study is limited by the use of one model of experimentally induced diabetes, the results obtained demonstrate for the first time that sulforaphane prevents diabetes-induced hepatic ferroptosis in vivo through the activation of Nrf2 signaling pathways. This nominates sulforaphane as a promising phytopharmaceutical for the prevention/alleviation of ferroptosis in diabetes-related pathologies.

Unveiling the Nutritional Veil of Sulforaphane: With a Major Focus on Glucose Homeostasis Modulation

Abnormal glucose homeostasis is associated with metabolic syndromes including cardiovascular diseases, hypertension, type 2 diabetes mellitus, and obesity, highlighting the significance of maintaining a balanced glucose level for optimal biological function. This highlights the importance of maintaining normal glucose levels for proper biological functioning. Sulforaphane (SFN), the primary bioactive compound in broccoli from the Cruciferae or Brassicaceae family, has been shown to enhance glucose homeostasis effectively while exhibiting low cytotoxicity. This paper assesses the impact of SFN on glucose homeostasis in vitro, in vivo, and human trials, as well as the molecular mechanisms that drive its regulatory effects. New strategies have been proposed to enhance the bioavailability and targeted delivery of SFN in order to overcome inherent instability. The manuscript also covers the safety evaluations of SFN that have been documented for its production and utilization. Hence, a deeper understanding of the favorable influence and mechanism of SFN on glucose homeostasis, coupled with the fact that SFN is abundant in the human daily diet, may ultimately offer theoretical evidence to support its potential use in the food and pharmaceutical industries.

Targeting autophagy in diabetic cardiomyopathy: From molecular mechanisms to pharmacotherapy

Diabetic cardiomyopathy (DCM) is a cardiac microvascular complication caused by metabolic disorders. It is characterized by myocardial remodeling and dysfunction. The pathogenesis of DCM is associated with abnormal cellular metabolism and organelle accumulation. Autophagy is thought to play a key role in the diabetic heart, and a growing body of research suggests that modulating autophagy may be a potential therapeutic strategy for DCM. Here, we have summarized the major signaling pathways involved in the regulation of autophagy in DCM, including Adenosine 5'-monophosphate-activated protein kinase (AMPK), mechanistic target of rapamycin (mTOR), Forkhead box subfamily O proteins (FOXOs), Sirtuins (SIRTs), and PTEN-inducible kinase 1 (PINK1)/Parkin. Given the significant role of autophagy in DCM, we further identified natural products and chemical drugs as regulators of autophagy in the treatment of DCM. This review may help to better understand the autophagy mechanism of drugs for DCM and promote their clinical application.

Anti-Inflammatory Therapeutic Mechanisms of Isothiocyanates: Insights from Sulforaphane

Isothiocyanates (ITCs) belong to a group of natural products that possess a highly reactive electrophilic -N=C=S functional group. They are stored in plants as precursor molecules, glucosinolates, which are processed by the tyrosinase enzyme upon plant tissue damage to release ITCs, along with other products. Isolated from broccoli, sulforaphane is by far the most studied antioxidant ITC, acting primarily through the induction of a transcription factor, the nuclear factor erythroid 2-related factor 2 (Nrf2), which upregulates downstream antioxidant genes/proteins. Paradoxically, sulforaphane, as a pro-oxidant compound, can also increase the levels of reactive oxygen species, a mechanism which is attributed to its anticancer effect. Beyond highlighting the common pro-oxidant and antioxidant effects of sulforaphane, the present paper was designed to assess the diverse anti-inflammatory mechanisms reported to date using a variety of in vitro and in vivo experimental models. Sulforaphane downregulates the expression of pro-inflammatory cytokines, chemokines, adhesion molecules, cycloxyhenase-2, and inducible nitric oxide synthase. The signalling pathways of nuclear factor κB, activator protein 1, sirtuins 1, silent information regulator sirtuin 1 and 3, and microRNAs are among those affected by sulforaphane. These anti-inflammatory actions are sometimes due to direct action via interaction with the sulfhydryl structural moiety of cysteine residues in enzymes/proteins. The following are among the topics discussed in this paper: paradoxical signalling pathways such as the immunosuppressant or immunostimulant mechanisms; crosstalk between the oxidative and inflammatory pathways; and effects dependent on health and disease states.

Targeting autophagy with natural products as a potential therapeutic approach for diabetic microangiopathy

As the quality of life improves, the incidence of diabetes mellitus and its microvascular complications (DMC) continues to increase, posing a threat to people's health and wellbeing. Given the limitations of existing treatment, there is an urgent need for novel approaches to prevent and treat DMC. Autophagy, a pivotal mechanism governing metabolic regulation in organisms, facilitates the removal of dysfunctional proteins and organelles, thereby sustaining cellular homeostasis and energy generation. Anomalous states in pancreatic β-cells, podocytes, Müller cells, cardiomyocytes, and Schwann cells in DMC are closely linked to autophagic dysregulation. Natural products have the property of being multi-targeted and can affect autophagy and hence DMC progression in terms of nutrient perception, oxidative stress, endoplasmic reticulum stress, inflammation, and apoptosis. This review consolidates recent advancements in understanding DMC pathogenesis via autophagy and proposes novel perspectives on treating DMC by either stimulating or inhibiting autophagy using natural products.

SESN2-Mediated AKT/GSK-3β/NRF2 Activation to Ameliorate Adriamycin Cardiotoxicity in High-Fat Diet-Induced Obese Mice

Aims: Obese patients are highly sensitive to adriamycin (ADR)-induced cardiotoxicity. However, the potential mechanism of superimposed toxicity remains to be elucidated. Sestrin 2 (SESN2), a potential antioxidant, could attenuate stress-induced cardiomyopathy; therefore, this study aims to explore whether SESN2 enhances cardiac resistance to ADR-induced oxidative damage in high-fat diet (HFD)-induced obese mice. Results: The results revealed that obesity decreased SESN2 expression in ADR-exposed heart. And, HFD mice may predispose to ADR-induced cardiotoxicity, which was probably associated with inhibiting protein kinase B (AKT), glycogen synthase kinase-3 beta (GSK-3β) phosphorylation and subsequently blocking nuclear localization of nuclear factor erythroid-2 related factor 2 (NRF2), ultimately resulting in cardiac oxidative damage. However, these destructive cascades and cardiac oxidative damage effects induced by HFD/sodium palmitate combined with ADR were blocked by overexpression of SESN2. Moreover, the antioxidant effect of SESN2 could be largely abolished by sh-Nrf2 or wortmannin. And sulforaphane, an NRF2 agonist, could remarkably reverse cardiac pathological and functional abnormalities caused by ADR in obese mice. Innovation and Conclusion: This study demonstrated that SESN2 might be a promising therapeutic target for improving anthracycline-related cardiotoxicity in obesity by upregulating activity of NRF2 via AKT/GSK-3β/Src family tyrosine kinase signaling pathway. Antioxid. Redox Signal. 40, 598-615.

Acetylated Histone Modifications: Intersection of Diabetes and Atherosclerosis

ABSTRACT

Worldwide, type 2 diabetes is predominant form of diabetes, and it is mainly affected by the environment. Furthermore, the offspring of patients with type 2 diabetes and metabolic disorder syndrome may have a higher risk of diabetes and cardiovascular disease, which indicates that the environmental impact on diabetes prevalence can be transmitted across generations. In the process of diabetes onset and intergenerational transmission, the genetic structure of the individual is not directly changed but is regulated by epigenetics. In this process, genes or histones are modified, resulting in selective expression of proteins. This modification will affect not only the onset of diabetes but also the related onset of atherosclerosis. Acetylation and deacetylation may be important regulatory factors for the above lesions. Therefore, in this review, based on the whole process of atherosclerosis evolution, we explored the possible existence of acetylation/deacetylation caused by diabetes. However, because of the lack of atherosclerosis-related acetylation studies directly based on diabetic models, we also used a small number of experiments involving nondiabetic models of related molecular mechanisms.

Lipid peroxidation products' role in autophagy regulation

Autophagy, which is responsible for removing damaged molecules, prevents their accumulation in cells, thus maintaining intracellular homeostasis. It is also responsible for removing the effects of oxidative stress, so its activation takes place during increased reactive oxygen species (ROS) generation and lipid peroxidation. Therefore, the aim of this review was to summarize all the available knowledge about the effect of protein modifications by lipid peroxidation products on autophagy activation and the impact of this interaction on the functioning of cells. This review shows that reactive aldehydes (including 4-hydroxynonenal and malondialdehyde), either directly or by the formation of adducts with autophagic proteins, can activate or prevent autophagy, depending on their concentration. This effect relates not only to the initial stages of autophagy, when 4-hydroxynonenal and malondialdehyde affect the levels of proteins involved in autophagy initiation and phagophore formation, but also to the final stage, degradation, when reactive aldehydes, by binding to the active center of cathepsins, inactivate their proteolytic functions. Moreover, this review also shows how little research exists on analyzing the impact of lipid peroxidation products and their protein adducts on autophagy. Such knowledge could be used in the therapy of diseases related to autophagy disorders.

Nrf2 for a key member of redox regulation: A novel insight against myocardial ischemia and reperfusion injuries

Nuclear factor erythroid-2 related factor 2 (Nrf2), a nuclear transcription factor, modulates genes responsible for antioxidant responses against toxic and oxidative stress to maintain redox homeostasis and participates in varieties of cellular processes such as metabolism and inflammation during myocardial ischemia and reperfusion injuries (MIRI). The accumulation of reactive oxygen species (ROS) from damaged mitochondria, xanthine oxidase, NADPH oxidases, and inflammation contributes to depraved myocardial ischemia and reperfusion injuries. Considering that Nrf2 played crucial roles in antagonizing oxidative stress, it is reasonable to delve into the up or down-regulated molecular mechanisms of Nrf2 in the progression of MIRI to provide the possibility of new therapeutic medicine targeting Nrf2 in cardiovascular diseases. This review systematically describes the generation of ROS, the regulatory metabolisms of Nrf2 as well as several natural or synthetic compounds activating Nrf2 during MIRI, which might provide novel insights for the anti-oxidative stress and original ideas targeting Nrf2 for the prevention and treatment in cardiovascular diseases.

A mechanistic overview of sulforaphane and its derivatives application in diabetes and its complications

Sulforaphane (SFN) is a type of phytochemical found in many cruciferous vegetables that has been shown to positively benefit the control of Type 2 Diabetes Mellitus (T2DM). The search was done from 2000 until December 2022 using PubMed, Scopus, Web of Sciences, and Google Scholar databases. We included all in vitro, in vivo, and clinical trials. Sulforaphane has been demonstrated to activate the PI3K/AKT and AMP-activated protein kinase pathways and the glucose transporter type 4 to increase insulin production and reduce insulin resistance. Interestingly, SFN possesses protective effects against diabetes complications, such as diabetic-induced hepatic damage, vascular inflammation and endothelial dysfunction, nephropathy, and neuropathy via nuclear factor erythroid 2-related factor 2 activation that leads to the translation of several anti-oxidant enzymes and regulation glycolysis, pentose phosphate pathway, fatty acid metabolism, glutamine metabolism, and glutathione metabolism. Furthermore, multiple clinical trial studies emphasized the ameliorating effects of SFN on T2DM patients. This review provides sufficient evidence for further research and development of sulforaphane as a hypoglycemic drug.

Dynamic changes in cardiac morphology, function, and diffuse myocardial fibrosis duration of diabetes in type 1 and type 2 diabetic mice models using 7.0 T CMR and echocardiography

Background

Diabetes mellitus (DM) is associated with an increased risk of cardiovascular disease (CVD). Hence, early detection of cardiac changes by imaging is crucial to reducing cardiovascular complications.

Purpose

Early detection of cardiac changes is crucial to reducing cardiovascular complications. The study aimed to detect the dynamic change in cardiac morphology, function, and diffuse myocardial fibrosis(DMF) associated with T1DM and T2DM mice models.

Materials and methods

4-week-old C57Bl/6J male mice were randomly divided into control (n=30), T1DM (n=30), and T2DM (n=30) groups. A longitudinal study was conducted every 4 weeks using serial 7.0T CMR and echocardiography imaging. Left ventricular ejection fraction (LV EF), tissue tracking parameters, and DMF were measured by cine CMR and extracellular volume fraction (ECV). Global peak circumferential strain (GCPS), peak systolic strain rate (GCPSSR) values were acquired by CMR feature tracking. LV diastolic function parameter (E/E') was acquired by echocardiography. The correlations between the ECV and cardiac function parameters were assessed by Pearson's test.

Results

A total of 6 mice were included every 4 weeks in control, T1DM, and T2DM groups for analysis. Compared to control group, an increase was detected in the LV mass and E/E' ratio, while the values of GCPS, GCPSSR decreased mildly in DM. Compared to T2DM group, GCPS and GCPSSR decreased earlier in T1DM(GCPS 12W,P=0.004; GCPSSR 12W,P=0.04). ECV values showed a significant correlation with GCPS and GCPSSR in DM groups. Moreover, ECV values showed a strong positive correlation with E/E'(T1DM,r=0.757,P<0.001;T2DM, r=0.811,P<0.001).

Conclusion

The combination of ECV and cardiac mechanical parameters provide imaging biomakers for pathophysiology, early diagnosis of cardiac morphology, function and early intervention in diabetic cardiomyopathy in the future.

CXCR7 Agonist TC14012 Improves Angiogenic Function of Endothelial Progenitor Cells via Activating Akt/eNOS Pathway and Promotes Ischemic Angiogenesis in Diabetic Limb Ischemia

PURPOSE

Endothelial progenitor cells (EPCs) play a critical role in repairing damaged vessels and triggering ischemic angiogenesis, but their number is reduced and function is impaired under diabetic conditions. Improving EPC function has been considered a promising strategy to ameliorate diabetic vascular complications. In the present study, we aim to investigate whether and how CXCR7 agonist TC14012 promotes the angiogenic function of diabetic EPCs.

METHODS

High glucose (HG) treatment was used to mimic the hyperglycemia in diabetes. Tube formation, cell scratch recovery and transwell assay, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, and cleaved-caspase3 expression were used to evaluate the angiogenic capability, cell migration, and apoptosis of EPCs, respectively. Hind limb ischemia (HLI) model was used to appraise the ability of TC14012 in promoting diabetic ischemic angiogenesis in vivo.

RESULTS

HG treatment impaired EPC tube formation and migration, and induced EPC apoptosis and oxidative damage, while TC14012 rescued tube formation and migration, and prevented HG-induced apoptosis and oxidative damage of EPCs. Furthermore, these beneficial effects of TC14012 on EPCs were attenuated by specific siRNAs against CXCR7, validating that CXCR7 is a functional target of TC14012 in EPCs. Mechanistic studies demonstrated that HG treatment reduced CXCR7 expression in EPCs, and impaired Akt and endothelial nitric oxide synthase (eNOS) phosphorylation and nitric oxide (NO) production; similarly, these signal impairments in HG-exposed EPCs could be rescued by TC14012. However, the protective effects of TC14012 on tube formation and migration, Akt and eNOS phosphorylation, and NO production in HG-treated EPCs were almost completely abolished by siRNAs against CXCR7 or Akt specific inhibitor wortmannin. More importantly, in vivo study showed that TC14012 administration enhanced blood perfusion recovery and angiogenesis in the ischemic hind limb and increased the EPC number in peripheral circulation of db/db mice, demonstrating the capability of TC14012 in promoting EPC mobilization and ischemia angiogenic function.

CONCLUSION

TC14012 can prevent EPCs from HG-induced dysfunction and apoptosis, improve eNOS activity and NO production via CXCR7/Akt signal pathway, and promote EPC mobilization and diabetic ischemia angiogenesis.

Effects of Vitamin D3 Supplementation and Aerobic Training on Autophagy Signaling Proteins in a Rat Model Type 2 Diabetes Induced by High-Fat Diet and Streptozotocin

The aim of this study was to investigate the combined effects of vitamin D3 supplementation and aerobic training on regulating the autophagy process in rats with type 2 diabetic induced by a high-fat diet and streptozotocin. A total of 40 Wistar rats were divided into five groups: normal control (NC), diabetic control (DC), diabetic + aerobic training (DAT), diabetic + vitamin D3 (DVD), and diabetic + aerobic training + vitamin D3 (DVDAT). The rats underwent eight weeks of aerobic training with an intensity of 60% maximum running speed for one hour, along with weekly subcutaneous injections of 10,000 units of vitamin D3. The protein levels of different autophagy markers were assessed in the left ventricular heart tissue. The results showed that the protein levels of AMPK, pAMPK, mTOR, and pmTOR were significantly lower in the DC group compared to the NC group. Conversely, the levels of ULK, Beclin-1, LC3II, Fyco, and Cathepsin D proteins were significantly higher in the DC group. However, the interventions of aerobic training and vitamin D3 supplementation, either individually or in combination, led to increased levels of AMPK, pAMPK, mTOR, and pmTOR, and decreased levels of ULK, Beclin-1, LC3II, Fyco, and Cathepsin D (p < 0.05). Additionally, the aerobic capacity in the DAT and DVDAT groups was significantly higher compared to the NC, DC, and DVD groups (p < 0.05). These findings suggest that type 2 diabetes is associated with excessive autophagy in the left ventricle. However, after eight weeks of vitamin D3 supplementation and aerobic training, a significant reduction in excessive autophagy was observed in rats with type 2 diabetes.

Physical activity in a swimming pool attenuates memory impairment by reducing glutamate and inflammatory cytokines and increasing BDNF in the brain of mice with type 2 diabetes

Type 2 diabetes is a risk factor for the development of cognitive impairment. Increasing evidence suggests that regular exercise is beneficial for the treatment of clinical symptoms in diabetic patients. The current study aimed to evaluate whether increasing physical activity through swimming training can reduce memory impairment in an animal model of type 2 diabetes. Diabetes and non-diabetes mice underwent swimming training for four weeks, and then working, spatial, and recognition memory were evaluated using three behavioral tests. Body weight, glucose, and insulin resistance were monitored. We also measured inflammatory cytokines (interleukin (IL)- 6, IL-1β, and tumor-necrosis-factor (TNF)-α), an anti-inflammatory cytokine (IL-10), and brain-derived-neurotrophic-factor (BDNF), and glutamate levels in the hippocampus or prefrontal cortex of mice. The findings showed that diabetes increased body weight, glucose, and insulin resistance, impaired working, spatial and recognition memory, increased levels of IL-6, IL-1β, TNF-α, and glutamate levels, and decreased BDNF in the hippocampus of diabetic mice. While higher physical activity was associated with reduced body weight, glucose, and insulin resistance, attenuated memory impairment, IL-6, IL-1β, TNF-α, and glutamate, and increased BDNF levels in the hippocampus and prefrontal cortex of diabetic mice. This study shows that swimming training can normalize body weight and glucose-insulin axis and reduce inflammation and glutamate in the hippocampus and enhance the neurotrophic system in both the hippocampus and prefrontal cortex of diabetic mice. This study also suggests that higher physical activity through swimming training can improve cognitive impairment in a mouse model of type 2 diabetes.

Endothelial dysfunction, platelet hyperactivity, hypertension, and the metabolic syndrome: molecular insights and combating strategies

Metabolic syndrome (MetS) is a multifaceted condition that increases the possibility of developing atherosclerotic cardiovascular disease. MetS includes obesity, hypertension, dyslipidemia, hyperglycemia, endothelial dysfunction, and platelet hyperactivity. There is a concerning rise in the occurrence and frequency of MetS globally. The rising incidence and severity of MetS need a proactive, multipronged strategy for identifying and treating those affected. For many MetS patients, achieving recommended goals for healthy fat intake, blood pressure control, and blood glucose management may require a combination of medicine therapy, lifestyles, nutraceuticals, and others. However, it is essential to note that lifestyle modification should be the first-line therapy for MetS. In addition, MetS requires pharmacological, nutraceutical, or other interventions. This review aimed to bring together the etiology, molecular mechanisms, and dietary strategies to combat hypertension, endothelial dysfunction, and platelet dysfunction in individuals with MetS.

Old and Novel Predictors for Cardiovascular Risk in Diabetic Foot Syndrome—A Narrative Review

Diabetic foot syndrome (DFS) is a complication associated with diabetes that has a strong negative impact, both medically and socio-economically. Recent epidemiological data show that one in six patients with diabetes will develop an ulcer in their lifetime. Vascular complications associated with diabetic foot have multiple prognostic implications in addition to limiting functional status and leading to decreased quality of life for these patients. We searched the electronic databases of PubMed, MEDLINE and EMBASE for studies that evaluated the role of DFS as a cardiovascular risk factor through the pathophysiological mechanisms involved, in particular the inflammatory ones and the associated metabolic changes. In the era of evidence-based medicine, the management of these cases in multidisciplinary teams of “cardio-diabetologists” prevents the occurrence of long-term disabling complications and has prognostic value for cardiovascular morbidity and mortality among diabetic patients. Identifying artificial-intelligence-based cardiovascular risk prediction models or conducting extensive clinical trials on gene therapy or potential therapeutic targets promoted by in vitro studies represent future research directions with a modulating role on the risk of morbidity and mortality in patients with DFS.

Bibliometric analysis of the inflammation in diabetic cardiomyopathy

Background

Maladaptive inflammation is implicated in the development of diabetic cardiomyopathy (DCM). This study aimed to visually analyze the global scientific output over the past two decades regarding research on inflammation associated with DCM.

Methods

All relevant articles and reviews were retrieved in the Web of Science (WOS) Core Collection (limited to SCIE) using "inflammation" and "diabetic cardiomyopathy" as search terms. Articles and reviews published from 1 January 2001 to 28 February 2021 were collected. Visualization analysis and statistical analysis were conducted by Microsoft 365 Excel and VOSviewer 1.6.18.

Results

A total of 578 documents were finally selected for further analysis. The publications regarding inflammation and DCM increased gradually over approximately 20 years. The most prolific country was China, with 296 documents and the most citations (9,366). The most influential author groups were Lu Cai and Yihui Tan who were from the United States. The bibliometric analysis of co-occurrence keywords showed that inflammation in DCM is composed of numerous molecules (NF-κB, NLRP3 inflammasome, Nrf-2, TNF-α, protein kinase C, PPARα, TLR4, p38 mitogen-activated protein kinase, TGF-β, Sirt1, and AKT), a variety of cardiac cell types (stem cell, fibroblast, and cardiomyocyte), physiological processes (apoptosis, oxidative stress, autophagy, endoplasmic reticulum stress, hypertrophy, mitochondrion dysfunction, and proliferation), and drugs (sulforaphane, metformin, empagliflozin, and rosuvastatin).

Conclusion

Our bibliometric analysis presents the characteristics and trends of inflammation in DCM and shows that research on inflammation in DCM will continue to be a hotspot.

SIRT6 Mitigates Heart Failure With Preserved Ejection Fraction in Diabetes

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF) is a growing health problem without effective therapies. Epidemiological studies indicate that diabetes is a strong risk factor for HFpEF, and about 45% of patients with HFpEF are suffering from diabetes, yet the underlying mechanisms remain elusive.

METHODS

Using a combination of echocardiography, hemodynamics, RNA-sequencing, molecular biology, in vitro and in vivo approaches, we investigated the roles of SIRT6 (sirtuin 6) in regulation of endothelial fatty acid (FA) transport and HFpEF in diabetes.

RESULTS

We first observed that endothelial SIRT6 expression was markedly diminished in cardiac tissues from heart failure patients with diabetes. We then established an experimental mouse model of HFpEF in diabetes induced by a combination of the long-term high-fat diet feeding and a low-dose streptozocin challenge. We also generated a unique humanized SIRT6 transgenic mouse model, in which a single copy of human SIRT6 transgene was engineered at mouse Rosa26 locus and conditionally induced with the Cre-loxP technology. We found that genetically restoring endothelial SIRT6 expression in the diabetic mice ameliorated diastolic dysfunction concurrently with decreased cardiac lipid accumulation. SIRT6 gain- or loss-of-function studies showed that SIRT6 downregulated endothelial FA uptake. Mechanistically, SIRT6 suppressed endothelial expression of PPARγ through SIRT6-dependent deacetylation of histone H3 lysine 9 around PPARγ promoter region; and PPARγ reduction mediated SIRT6-dependent inhibition of endothelial FA uptake. Importantly, oral administration of small molecule SIRT6 activator MDL-800 to diabetic mice mitigated cardiac lipid accumulation and diastolic dysfunction.

CONCLUSIONS

The impairment of endothelial SIRT6 expression links diabetes to HFpEF through the alteration of FA transport across the endothelial barrier. Genetic and pharmacological strategies that restored endothelial SIRT6 function in mice with diabetes alleviated experimental HFpEF by limiting FA uptake and improving cardiac metabolism, thus warranting further clinical evaluation.

Sulforaphane Protects against Unilateral Ureteral Obstruction-Induced Renal Damage in Rats by Alleviating Mitochondrial and Lipid Metabolism Impairment

Unilateral ureteral obstruction (UUO) is an animal rodent model that allows the study of obstructive nephropathy in an accelerated manner. During UUO, tubular damage is induced, and alterations such as oxidative stress, inflammation, lipid metabolism, and mitochondrial impairment favor fibrosis development, leading to chronic kidney disease progression. Sulforaphane (SFN), an isothiocyanate derived from green cruciferous vegetables, might improve mitochondrial functions and lipid metabolism; however, its role in UUO has been poorly explored. Therefore, we aimed to determine the protective effect of SFN related to mitochondria and lipid metabolism in UUO. Our results showed that in UUO SFN decreased renal damage, attributed to increased mitochondrial biogenesis. We showed that SFN augmented peroxisome proliferator-activated receptor γ co-activator 1α (PGC-1α) and nuclear respiratory factor 1 (NRF1). The increase in biogenesis augmented the mitochondrial mass marker voltage-dependent anion channel (VDAC) and improved mitochondrial structure, as well as complex III (CIII), aconitase 2 (ACO2) and citrate synthase activities in UUO. In addition, lipid metabolism was improved, observed by the downregulation of cluster of differentiation 36 (CD36), sterol regulatory-element binding protein 1 (SREBP1), fatty acid synthase (FASN), and diacylglycerol O-acyltransferase 1 (DGAT1), which reduces triglyceride (TG) accumulation. Finally, restoring the mitochondrial structure reduced excessive fission by decreasing the fission protein dynamin-related protein-1 (DRP1). Autophagy flux was further restored by reducing beclin and sequestosome (p62) and increasing B-cell lymphoma 2 (Bcl2) and the ratio of microtubule-associated proteins 1A/1B light chain 3 II and I (LC3II/LC3I). These results reveal that SFN confers protection against UUO-induced kidney injury by targeting mitochondrial biogenesis, which also improves lipid metabolism.

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.

Gut microbiota: A new therapeutic target for diabetic cardiomyopathy

Diabetic cardiomyopathy seriously affects quality of life and even threatens life safety of patients. The pathogenesis of diabetic cardiomyopathy is complex and multifactorial, and it is widely accepted that its mechanisms include oxidative stress, inflammation, insulin resistance, apoptosis, and autophagy. Some studies have shown that gut microbiota plays an important role in cardiovascular diseases. Gut microbiota and its metabolites can affect the development of diabetic cardiomyopathy by regulating oxidative stress, inflammation, insulin resistance, apoptosis, and autophagy. Here, the mechanisms of gut microbiota and its metabolites resulting in diabetic cardiomyopathy are reviewed. Gut microbiota may be a new therapeutic target for diabetic cardiomyopathy.

LKB1: An emerging therapeutic target for cardiovascular diseases

Cardiovascular diseases (CVDs) are currently the most common cause of morbidity and mortality worldwide. Experimental studies suggest that liver kinase B1 (LKB1) plays an important role in the heart. Several studies have shown that cardiomyocyte-specific LKB1 deletion leads to hypertrophic cardiomyopathy, left ventricular contractile dysfunction, and an increased risk of atrial fibrillation. In addition, the cardioprotective effects of several medicines and natural compounds, including metformin, empagliflozin, bexarotene, and resveratrol, have been reported to be associated with LKB1 activity. LKB1 limits the size of the damaged myocardial area by modifying cellular metabolism, enhancing the antioxidant system, suppressing hypertrophic signals, and inducing mild autophagy, which are all primarily mediated by the AMP-activated protein kinase (AMPK) energy sensor. LKB1 also improves myocardial efficiency by modulating the function of contractile proteins, regulating the expression of electrical channels, and increasing vascular dilatation. Considering these properties, stimulation of LKB1 signaling offers a promising approach in the prevention and treatment of heart diseases.

The Dynamic Characteristics of Myocardial Contractility and Extracellular Volume in Type 2 Diabetes Mellitus Mice Investigated by 7.0T Cardiac Magnetic Resonance

Type 2 diabetes mellitus (T2DM) is associated with a high prevalence of diastolic dysfunction and congestive heart failure. A potential contributing factor is the accelerated accumulation of diffuse myocardial fibrosis and stiffness. Novel cardiac magnetic resonance (CMR) imaging techniques can identify both myocardial fibrosis and contractility quantitatively. This study aimed to investigate the dynamic characteristics of the myocardial strain and altered extracellular volume (ECV) fraction as determined by 7.0 T CMR in T2DM mice. C57Bl/6J mice were randomly divided into T2DM (fed a high-fat diet) and control (fed a normal diet) groups. They were scanned on 7.0 T MRI every 4 weeks until the end of week 24. The CMR protocol included multi-slice cine imaging to assess left ventricle strain and strain rate, and pre- and post-contrast T1 mapping images to quantify ECV. The ECV in the T2DM mice was significantly higher (p < 0.05) than that in the control group since week 12 with significantly impaired myocardial strain (p < 0.05). A significant linear correlation was established between myocardial strain and ECV (p < 0.001) and left ventricular-ejection fraction and ECV (p = 0.003). The results suggested that CMR feature tracking-derived myocardial strain analysis can assess functional abnormalities that may be associated with ECM alterations in diabetic cardiomyopathy, contributing to the study of diabetic therapy effects.

Naoxintong Capsule Activates the Nrf2/HO-1 Signaling Pathway and Suppresses the p38α Signaling Pathway Via Estrogen Receptors to Ameliorate Heart Remodeling in Female Mice With Postmenopausal Hypertension

ABSTRACT

Limited treatments are available for alleviating heart remodeling in postmenopausal hypertension. The cardioprotective effect of naoxintong (NXT) has been widely accepted. This study aimed to explore the effects of NXT on pathological heart remodeling in a postmenopausal hypertension mouse model in vivo and H9c2 cardiomyocytes in vitro. In vivo, ovariectomy combined with chronic angiotensin II infusion was used to establish the postmenopausal hypertension animal model. NXT significantly ameliorated cardiac remodeling as indicated by a reduced ratio of heart weight/body weight and left ventricle weight/body weight, left ventricular wall thickness, diameter of cardiomyocytes, and collagen deposition in the heart. NXT also significantly increased the expression of estrogen receptors (ERs) and downregulated the expression of nicotinamide adenine dinucleotide phosphate oxidase 2 (Nox2). In vitro, NXT treatment greatly suppressed angiotensin II-induced cardiac hypertrophy, cardiac fibrosis, and excessive oxidative stress as proven by reducing the diameter of H9c2 cardiomyocytes, expression of hypertrophy and fibrosis markers, intracellular reactive oxygen species, and oxidative enzymes. Mechanistically, NXT significantly upregulated the expression of ERs, which activated the Nrf2/HO-1 signaling pathway and inhibited the phosphorylation of the p38α pathway. Collectively, the results indicated that NXT administration might attenuate cardiac remodeling through upregulating the expression of ERs, which activated the Nrf2/HO-1 signaling pathway, inhibited the phosphorylation of the p38α signaling pathway, and reduced oxidative stress.

Sulforaphane suppresses the activity of sterol regulatory element-binding proteins (SREBPs) by promoting SREBP precursor degradation

Sterol regulatory element-binding proteins (SREBPs) are transcription factors that regulate various genes involved in cholesterol and fatty acid synthesis. In this study, we describe that naturally occurring isothiocyanate sulforaphane (SFaN) impairs fatty acid synthase promoter activity and reduces SREBP target gene (e.g., fatty acid synthase and acetyl-CoA carboxylase 1) expression in human hepatoma Huh-7 cells. SFaN reduced SREBP proteins by promoting the degradation of the SREBP precursor. Amino acids 595–784 of SREBP-1a were essential for SFaN-mediated SREBP-1a degradation. We also found that such SREBP-1 degradation occurs independently of the SREBP cleavage-activating protein and the Keap1-Nrf2 pathway. This study identifies SFaN as an SREBP inhibitor and provides evidence that SFaN could have major potential as a pharmaceutical preparation against hepatic steatosis and obesity.

MDM2-mediated ubiquitination of LKB1 contributes to the development of diabetic cataract

Diabetic cataract (DC) is a common complication of diabetes mellitus. The epithelial-mesenchymal transition (EMT) of lens epithelial cells (LECs) is a crucial event in the development of DC. Murine double minute 2 (MDM2) is an E3 ubiquitin ligase that promotes EMT by regulating diverse targets. However, little is known about how MDM2 is involved in the pathogenesis of DC. We found the mRNA and protein levels of MDM2 were up-regulated in the lens of DC patients and rats. Thus, high glucose (HG)-induced human lens epithelial cells (HLECs) were constructed for further investigation. The results showed that the level of MDM2 was increased in HG-cultured HLECs, and the MDM2 knockdown alleviated HG-induced abnormal migration, EMT, and oxidative stress damage. Moreover, co-immunoprecipitation and ubiquitination assays demonstrated that MDM2 down-regulated LKB1 expression by ubiquitination degradation. LKB1 was found to be lower expressed in human and rat DC lenses, and HG-stimulated HLECs. Also, LKB1 overexpression mitigated HG-induced dysfunction of HLECs. Finally, our data showed that the changes related to EMT and oxidative stress induced by MDM2 knockdown were restored by down-regulation of LKB1. Together, MDM2 may involve in the pathogenesis of DC through down-regulating LKB1. MDM2 might be an effective therapeutical target of DC.

Targeting NRF2 in Type 2 diabetes mellitus and depression: Efficacy of natural and synthetic compounds

Evidence supports a strong bidirectional association between depression and Type 2 diabetes mellitus (T2DM). The harmful impact of oxidative stress and chronic inflammation on the development of both disorders is widely accepted. Nuclear factor erythroid 2-related factor 2 (NRF2) is a pertinent target in disease management owing to its reputation as the master regulator of antioxidant responses. NRF2 influences the expression of various cytoprotective phase 2 antioxidant genes, which is hampered in both depression and T2DM. Through interaction and crosstalk with several signaling pathways, NRF2 endeavors to contain the widespread oxidative damage and persistent inflammation involved in the pathophysiology of depression and T2DM. NRF2 promotes the neuroprotective and insulin-sensitizing properties of its upstream and downstream targets, thereby interrupting and preventing disease advancement. Standard antidepressant and antidiabetic drugs may be powerful against these disorders, but unfortunately, they come bearing distressing side effects. Therefore, exploiting the therapeutic potential of NRF2 activators presents an exciting opportunity to manage such bidirectional and comorbid conditions.

Cellular interplay between cardiomyocytes and non-myocytes in diabetic cardiomyopathy

Patients with Type 2 diabetes mellitus (T2DM) frequently exhibit a distinctive cardiac phenotype known as diabetic cardiomyopathy. Cardiac complications associated with T2DM include cardiac inflammation, hypertrophy, fibrosis and diastolic dysfunction in the early stages of the disease, which can progress to systolic dysfunction and heart failure. Effective therapeutic options for diabetic cardiomyopathy are limited and often have conflicting results. The lack of effective treatments for diabetic cardiomyopathy is due in part, to our poor understanding of the disease development and progression, as well as a lack of robust and valid preclinical human models that can accurately recapitulate the pathophysiology of the human heart. In addition to cardiomyocytes, the heart contains a heterogeneous population of non-myocytes including fibroblasts, vascular cells, autonomic neurons and immune cells. These cardiac non-myocytes play important roles in cardiac homeostasis and disease, yet the effect of hyperglycaemia and hyperlipidaemia on these cell types are often overlooked in preclinical models of diabetic cardiomyopathy. The advent of human induced pluripotent stem cells provides a new paradigm in which to model diabetic cardiomyopathy as they can be differentiated into all cell types in the human heart. This review will discuss the roles of cardiac non-myocytes and their dynamic intercellular interactions in the pathogenesis of diabetic cardiomyopathy. We will also discuss the use of sodium-glucose cotransporter 2 inhibitors as a therapy for diabetic cardiomyopathy and their known impacts on non-myocytes. These developments will no doubt facilitate the discovery of novel treatment targets for preventing the onset and progression of diabetic cardiomyopathy.

Cardiac SIRT1 ameliorates doxorubicin-induced cardiotoxicity by targeting sestrin 2

Although it is known that the expression and activity of sirtuin 1 (SIRT1) significantly decrease in doxorubicin (DOX)-induced cardiomyopathy, the role of interaction between SIRT1 and sestrin 2 (SESN2) is largely unknown. In this study, we investigated whether SESN2 could be a crucial target of SIRT1 and the effect of their regulatory interaction and mechanism on DOX-induced cardiac injury. Here, using DOX-treated cardiomyocytes and cardiac-specific Sirt1 knockout mice models, we found SIRT1 deficiency aggravated DOX-induced cardiac structural abnormalities and dysfunction, whereas the activation of SIRT1 by resveratrol (RES) treatment or SIRT1 overexpression possessed cardiac protective effects. Further studies indicated that SIRT1 exerted these beneficial effects by markedly attenuating DOX-induced oxidative damage and apoptosis in a SESN2-dependent manner. Knockdown of Sesn2 impaired RES/SIRT1-mediated protective effects, while upregulation of SESN2 efficiently rescued DOX-induced oxidative damage and apoptosis. Most importantly, SIRT1 activation could reduce DOX-induced SESN2 ubiquitination possibly through reducing the interaction of SESN2 with mouse double minute 2 (MDM2). The recovery of SESN2 stability in DOX-impaired primary cardiomyocytes by SIRT1 was confirmed by Mdm2-siRNA transfection. Taken together, our findings indicate that disrupting the interaction between SESN2 and MDM2 by SIRT1 to reduce the ubiquitination of SESN2 is a novel regulatory mechanism for protecting hearts from DOX-induced cardiotoxicity and suggest that the activation of SIRT1-SESN2 axis has potential as a therapeutic approach to prevent DOX-induced cardiotoxicity.

Recent Advances in KEAP1/NRF2-Targeting Strategies by Phytochemical Antioxidants, Nanoparticles, and Biocompatible Scaffolds for the Treatment of Diabetic Cardiovascular Complications

Significance: Modulation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2)-mediated antioxidant response is a key aspect in the onset of diabetes-related cardiovascular complications. With this review, we provide an overview of the recent advances made in the development of Nrf2-targeting strategies for the treatment of diabetes, with particular attention toward the activation of Nrf2 by natural antioxidant compounds, nanoparticles, and oxidative stress-modulating biocompatible scaffolds. Recent Advances: In the past 30 years, studies addressing the use of antioxidant therapies to treat diabetes have grown exponentially, showing promising but yet inconclusive results. Animal studies and clinical trials on the Nrf2 pathway have shown promising results, suggesting that its activation can delay or reverse some of the cardiovascular impairments in diabetes. Critical Issues: Hyperglycemia- and oscillating glucose levels-induced reactive oxygen species (ROS) accumulation is progressively emerging as a central factor in the onset and progression of diabetes-related cardiovascular complications, including endothelial dysfunction, retinopathy, heart failure, stroke, critical limb ischemia, ulcers, and delayed wound healing. In this context, accumulating evidence suggests a central role for Nrf2-mediated antioxidant response, one of the most studied cellular defensive mechanisms against ROS accumulation. Future Directions: Innovative approaches such as tissue engineering and nanotechnology are converging toward targeting oxidative stress in diabetes. Antioxid. Redox Signal. 36, 707-728.

Sulforaphane reduces obesity by reversing leptin resistance

The ascending prevalence of obesity in recent decades is commonly associated with soaring morbidity and mortality rates, resulting in increased health-care costs and decreased quality of life. A systemic state of stress characterized by low-grade inflammation and pathological formation of reactive oxygen species (ROS) usually manifests in obesity. The transcription factor nuclear factor erythroid-derived 2-like 2 (NRF2) is the master regulator of the redox homeostasis and plays a critical role in the resolution of inflammation. Here, we show that the natural isothiocyanate and potent NRF2 activator sulforaphane reverses diet-induced obesity through a predominantly, but not exclusively, NRF2-dependent mechanism that requires a functional leptin receptor signaling and hyperleptinemia. Sulforaphane does not reduce the body weight or food intake of lean mice but induces an anorectic response when coadministered with exogenous leptin. Leptin-deficient Lep^ob/ob mice and leptin receptor mutant Lepr^db/db mice display resistance to the weight-reducing effect of sulforaphane, supporting the conclusion that the antiobesity effect of sulforaphane requires functional leptin receptor signaling. Furthermore, our results suggest the skeletal muscle as the most notable site of action of sulforaphane whose peripheral NRF2 action signals to alleviate leptin resistance. Transcriptional profiling of six major metabolically relevant tissues highlights that sulforaphane suppresses fatty acid synthesis while promoting ribosome biogenesis, reducing ROS accumulation, and resolving inflammation, therefore representing a unique transcriptional program that leads to protection from obesity. Our findings argue for clinical evaluation of sulforaphane for weight loss and obesity-associated metabolic disorders.

Gut bacterial metabolite Urolithin A inhibits myocardial fibrosis through activation of Nrf2 pathway in vitro and in vivo

Background

Myocardial fibrosis after myocardial infarction (MI) is one of the leading causes of cardiovascular diseases. Cardiac fibroblasts (CFs) are activated and promoted by MI to undergo myofibroblast transformation (CMT). Urolithin A (UA) is an active and effective gut metabolite derived from polyphenolics of berries and pomegranate fruits, which has been reported to have anti-inflammatory and anti-oxidant functions. However, whether UA affects the CMT process during myocardial fibrosis remains unclear.

Methods

TGF-β1-treated primary rat cardiac fibroblasts were used for in vitro study. Cell proliferation ability was evaluated by MTT assay. Cell migration and invasion abilities were tested by wound healing and Transwell assays. The expression of CMT process-related markers were measured by qRT-PCR and western blot. The rat MI model was established by left anterior descending coronary artery (LAD) ligation and evaluated by H&E and Masson staining.

Results

Our data demonstrated that UA treatment could inhibit the CMT process in TGF-β1-induced CFs, including cell proliferation, migration and invasion abilities. Knocking down of Nrf2, which was activated by UA treatment, could mitigate the effects of UA treatment on CMT process. Moreover, in vivo administration of UA in rat MI model successfully up-regulated Nrf2 expression and improved the myocardial damage and fibrosis.

Conclusions

The study discovered the function and mechanism of UA on myocardial fibrosis and demonstrated the protective effects of UA administration through activation of Nrf2 pathway.

Novel Insights Into the Pathogenesis of Diabetic Cardiomyopathy and Pharmacological Strategies

Diabetic cardiomyopathy (DCM) is a severe complication of diabetes developed mainly in poorly controlled patients. In DCM, several clinical manifestations as well as cellular and molecular mechanisms contribute to its phenotype. The production of reactive oxygen species (ROS), chronic low-grade inflammation, mitochondrial dysfunction, autophagic flux inhibition, altered metabolism, dysfunctional insulin signaling, cardiomyocyte hypertrophy, cardiac fibrosis, and increased myocardial cell death are described as the cardinal features involved in the genesis and development of DCM. However, many of these features can be associated with broader cellular processes such as inflammatory signaling, mitochondrial alterations, and autophagic flux inhibition. In this review, these mechanisms are critically discussed, highlighting the latest evidence and their contribution to the pathogenesis of DCM and their potential as pharmacological targets.

Natural and chemical compounds as protective agents against cardiac lipotoxicity

Cardiac lipotoxicity results from the deleterious effects of excess lipid deposition in cardiomyocytes. Lipotoxic cardiomyopathy involves cardiac lipid overload leading to changes in myocardial structure and function. Cardiac dysfunction has been associated with cardiac lipotoxicity through abnormal lipid metabolism. Lipid accumulation, especially saturated free fatty acids (SFFAs), in cardiac cells can cause cardiomyocyte distress and subsequent myocardial contractile dysfunction. Reducing the excess FAs supply or promoting FA storage is beneficial for cardiac function, especially under a lipotoxic condition. The protective effects of several compounds against lipotoxicity progression in the heart have been investigated. A variety of mechanisms has been suggested to prevent or treat cardiac lipotoxicity, including improvement of calcium homeostasis, lipid metabolism, and mitochondrial dysfunction. Known targets and signaling pathways involving a select group of chemicals that interfere with cardiac lipotoxicity pathogenesis are reviewed.

Intravital assessment of precapillary pulmonary arterioles of type 1 diabetic mice shows oxidative damage and increased tone in response to NOS inhibition

Microvascular dilation, important for peripheral tissue glucose distribution, also modulates alveolar perfusion and is inhibited by loss of bioavailable nitric oxide (NO) in diabetes mellitus (DM). We hypothesized that DM-induced oxidative stress decreases bioavailable NO and pulmonary precapillary arteriolar diameter, causing endothelial injury. We examined subpleural pulmonary arterioles after acute NO synthase (NOS) inhibition with NG-nitro-l-arginine methyl ester (l-NAME) in streptozotocin (STZ)- and saline (CTRL)-treated C57BL/6J mice. Microvascular changes were assessed by intravital microscopy in the right lung of anesthetized mice with open chest and ventilated lungs. Arteriolar tone in pulmonary arterioles (27.2-48.7 µm diameter) increased in CTRL mice (18.0 ± 11% constriction, P = 0.034, n = 5) but decreased in STZ mice (13.6 ± 7.5% dilation, P = 0.009, n = 5) after l-NAME. Lung tissue dihydroethidium (DHE) fluorescence (superoxide), inducible NOS expression, and protein nitrosylation (3-nitrotyrosine) increased in STZ mice and correlated with increased glucose levels (103.8 ± 8.8 mg/dL). Fluorescently labeled fibrinogen administration and fibrinogen immunostaining showed fibrinogen adhesion, indicating endothelial injury in STZ mice. In CTRL mice, vasoconstriction to l-NAME was likely due to the loss of bioavailable NO. Vasodilation in STZ mice may be due to decreased formation of a vasoconstrictor or emergence of a vasodilator. These findings provide novel evidence that DM targets the pulmonary microcirculation and that decreased NO bioavailability and increased precapillary arteriolar tone could potentially lead to ventilation-perfusion abnormalities, exacerbating systemic DM complications.NEW & NOTEWORTHY Diabetes pulmonary and microvascular consequences are well recognized but have not been characterized. We assessed lung microvascular changes in a live anesthetized mouse model of type 1 diabetes, using a novel intravital microscopy technique. Our results show new evidence that a diabetes-induced decrease in lung nitric oxide bioavailability underlies oxidative damage, enhanced platelet activation, and endothelial injury causing pulmonary microvascular dysfunction and altered vasoreactivity. These findings could provide novel strategies to prevent or reverse diabetes systemic consequences.

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

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

High fat diet and its effects on cognitive health: alterations of neuronal and vascular components of brain

It has been well recognized that intake of diets rich in saturated fats could result in development of metabolic disorders such as type 2 diabetes mellitus, obesity and cardiovascular diseases. Recent studies have suggested that intake of high fat diet (HFD) is also associated with cognitive dysfunction. Various preclinical studies have demonstrated the impact of short and long term HFD feeding on the biochemical and behavioural alterations. This review summarizes studies and the protocols used to assess the impacts of HFD feeding on cognitive performance in rodents. Further, it discuss the key mechanisms that are altered by HFD feeding, such as, insulin resistance, oxidative stress, neuro-inflammation, transcriptional dysregulation and loss of synaptic plasticity. Along with these, HFD feeding also alters the vascular components of brain such as loss of BBB integrity and reduced cerebral blood flow. It is highly possible that these factors are responsible for the development of cognitive deficits as a result of HFD feeding.

Ferroptosis and Its Potential Role in Metabolic Diseases: A Curse or Revitalization?

Ferroptosis is classified as an iron-dependent form of regulated cell death (RCD) attributed to the accumulation of lipid hydroperoxides and redox imbalance. In recent years, accumulating researches have suggested that ferroptosis may play a vital role in the development of diverse metabolic diseases, for example, diabetes and its complications (e.g., diabetic nephropathy, diabetic cardiomyopathy, diabetic myocardial ischemia/reperfusion injury and atherosclerosis [AS]), metabolic bone disease and adrenal injury. However, the specific physiopathological mechanism and precise therapeutic effect is still not clear. In this review, we summarized recent advances about the development of ferroptosis, focused on its potential character as the therapeutic target in metabolic diseases, and put forward our insights on this topic, largely to offer some help to forecast further directions.

Autophagy in the diabetic heart: A potential pharmacotherapeutic target in diabetic cardiomyopathy

Association of diabetes with an elevated risk of cardiac failure has been clinically evident. Diabetes potentiates diastolic and systolic cardiac failure following the myocardial infarction that produces the cardiac muscle-specific microvascular complication, clinically termed as diabetic cardiomyopathy. Elevated susceptibility of diabetic cardiomyopathy is primarily caused by the generation of free radicals in the hyperglycemic milieu, compromising the myocardial contractility and normal cardiac functions with increasing redox insult, impaired mitochondria, damaged organelles, apoptosis, and cardiomyocytes fibrosis. Autophagy is essentially involved in the recycling/clearing the damaged organelles, cytoplasmic contents, and aggregates, which are frequently produced in cardiomyocytes. Although autophagy plays a vital role in maintaining the cellular homeostasis in diligent cardiac tissues, this process is frequently impaired in the diabetic heart. Given its clinical significance, accumulating evidence largely showed the functional aspects of autophagy in diabetic cardiomyopathy, elucidating its intricate protective and pathogenic outcomes. However, etiology and molecular readouts of these contrary autophagy activities in diabetic cardiomyopathy are not yet comprehensively assessed and translated. In this review, we attempted to assess the role of autophagy and its adaptations in the diabetic heart. To delineate the molecular consequences of these events, we provided detailed insights into the autophagy regulation pieces of machinery including the mTOR/AMPK, TFEB/ZNSCAN3, FOXOs, SIRTs, PINK1/Parkin, Nrf2, miRNAs, and others in the diabetic cardiomyopathy. Given the clinical significance of autophagy in the diabetic heart, we further discussed the potential pharmacotherapeutic strategies towards targeting autophagy. Taken together, the present report meticulously assessed autophagy, its adaptations, and molecular regulations in diabetic cardiomyopathy and reviewed the current autophagy-targeting strategies.

Sam68 promotes hepatic gluconeogenesis via CRTC2

Hepatic gluconeogenesis is essential for glucose homeostasis and also a therapeutic target for type 2 diabetes, but its mechanism is incompletely understood. Here, we report that Sam68, an RNA-binding adaptor protein and Src kinase substrate, is a novel regulator of hepatic gluconeogenesis. Both global and hepatic deletions of Sam68 significantly reduce blood glucose levels and the glucagon-induced expression of gluconeogenic genes. Protein, but not mRNA, levels of CRTC2, a crucial transcriptional regulator of gluconeogenesis, are >50% lower in Sam68-deficient hepatocytes than in wild-type hepatocytes. Sam68 interacts with CRTC2 and reduces CRTC2 ubiquitination. However, truncated mutants of Sam68 that lack the C- (Sam68^ΔC) or N-terminal (Sam68^ΔN) domains fails to bind CRTC2 or to stabilize CRTC2 protein, respectively, and transgenic Sam68^ΔN mice recapitulate the blood-glucose and gluconeogenesis profile of Sam68-deficient mice. Hepatic Sam68 expression is also upregulated in patients with diabetes and in two diabetic mouse models, while hepatocyte-specific Sam68 deficiencies alleviate diabetic hyperglycemia and improves insulin sensitivity in mice. Thus, our results identify a role for Sam68 in hepatic gluconeogenesis, and Sam68 may represent a therapeutic target for diabetes.

Hepatic gluconeogenesis is important for glucose homeostasis and a therapeutic target for type 2 diabetes. Here, the authors show that the RNA-binding adaptor protein Sam68 promotes the expression level of gluconeogenic genes and increases blood glucose levels by stabilizing the transcriptional coactivator CRTC2, while hepatic Sam68 deletion alleviates hyperglycemia in mice.

The Mystery of Diabetic Cardiomyopathy: From Early Concepts and Underlying Mechanisms to Novel Therapeutic Possibilities

Diabetic patients are predisposed to diabetic cardiomyopathy, a specific form of cardiomyopathy which is characterized by the development of myocardial fibrosis, cardiomyocyte hypertrophy, and apoptosis that develops independently of concomitant macrovascular and microvascular diabetic complications. Its pathophysiology is multifactorial and poorly understood and no specific therapeutic guideline has yet been established. Diabetic cardiomyopathy is a challenging diagnosis, made after excluding other potential entities, treated with different pharmacotherapeutic agents targeting various pathophysiological pathways that need yet to be unraveled. It has great clinical importance as diabetes is a disease with pandemic proportions. This review focuses on the potential mechanisms contributing to this entity, diagnostic options, as well as on potential therapeutic interventions taking in consideration their clinical feasibility and limitations in everyday practice. Besides conventional therapies, we discuss novel therapeutic possibilities that have not yet been translated into clinical practice.

Relationship between oxidative stress and nuclear factor-erythroid-2-related factor 2 signaling in diabetic cardiomyopathy (Review)

Diabetic cardiomyopathy (DCM) is the leading cause of death worldwide, and oxidative stress was discovered to serve an important role in the pathophysiology of the condition. An imbalance between free radicals and antioxidant defenses is known to be associated with cellular dysfunction, leading to the development of various types of cardiac disease. Nuclear factor-erythroid-2-related factor 2 (NRF2) is a transcription factor that controls the basal and inducible expression levels of various antioxidant genes and other cytoprotective phase II detoxifying enzymes, which are ubiquitously expressed in the cardiac system. Kelch-like ECH-associated protein 1 (Keap1) serves as the main intracellular regulator of NRF2. Emerging evidence has revealed that NRF2 is a critical regulator of cardiac homeostasis via the suppression of oxidative stress. The activation of NRF2 was discovered to enhance specific endogenous antioxidant defense factors, one of which is antioxidant response element (ARE), which was subsequently illustrated to detoxify and counteract oxidative stress-associated DCM. The NRF2 signaling pathway is closely associated with the development of various types of cardiac disease, including ischemic heart disease, heart failure, myocardial infarction, atrial fibrillation and myocarditis. Therefore, it is hypothesized that drugs targeting this pathway may be developed to inhibit the activation of NRF2 signaling, thereby preventing the occurrence of DCM and effectively treating the disease.

A review on herbal Nrf2 activators with preclinical evidence in cardiovascular diseases

Cardiovascular diseases (CVDs) are an ever-growing problem and are the most common cause of death worldwide. The uncontrolled production of reactive oxygen species (ROS) and the activation of ROS associated with various cell signaling pathways with oxidative cellular damage are the most common pathological conditions connected with CVDs including endothelial dysfunction, hypercontractility of vascular smooth muscle, cardiac hypertrophy and heart failure. The nuclear factor E2-related factor 2 (Nrf2) is a basic leucine zipper redox transcription factor, together with its negative regulator, kelch-like ECH-associated protein 1 (Keap1), which serves as a key regulator of cellular defense mechanisms to combat oxidative stress and associated diseases. Multiple lines of evidence described here support the cardiac protective property of Nrf2 in various experimental models of cardiac related disease conditions. In this review, we emphasized the molecular mechanisms of Nrf2 and described the detailed outline of current findings on the therapeutic possibilities of the Nrf2 activators specifically from herbal origin in various CVDs. Based on evidence from various preclinical experimental models, we have highlighted the activation of Nrf2 pathway as a budding therapeutic option for the prevention and treatment of CVDs, which needs further investigation and validation in the clinical settings.

Sulforaphane ameliorates lipid profile in rodents: an updated systematic review and meta-analysis

Sulforaphane (SFN), a naturally-occurring isothiocyanate enriched in cabbage and broccoli, has been provided as food supplements to improve weight management and reduce lipid levels. However, its effects on serum lipid profiles are contradictory. In this review, a meta-analysis and systematic review of SFN on lipid reduction and weight control is assessed with mice and rats fed on high-fat diet. The effects of SFN supplementation were evaluated by weighted mean difference (WMD) in body weight (BW), liver weight (LW) and also by its effect on serum lipids. A random-effects model was applied to estimate the overall summary effect. SFN reduced BW (WMD: − 2.76 g, 95% CI: − 4.19, − 1.34) and LW (WMD: − 0.93 g, 95% CI: − 1.63, − 0.23) significantly in our ten trials. Its effects on serum total cholesterol (TC) (WMD: − 15.62 mg/dL, 95% CI: − 24.07, − 7.18), low-density lipoprotein cholesterol (LDL-C) (WMD: − 8.35 mg/dL, 95% CI: − 15.47, − 1.24) and triglyceride (TG) (WMD: − 40.85 mg/dL, 95% CI: − 67.46, − 14.24) were significant except for high-density lipoprotein cholesterol (HDL-C) component (WMD: 1.05 mg/dL, 95% CI: − 3.44, 5.54). However, species, disease model, duration, SFN dosage as well as route of administration did not explain the heterogeneity among studies. In summary, these findings provide new insights concerning preclinical strategies for treating diseases including obesity, diabetes, hypertension, non-alcoholic fatty liver disease as well as cardiovascular disease with SFN supplements.