Protective Effect of Perilla Seed Meal and Perilla Seed Extract against Dextran Sulfate Sodium-Induced Ulcerative Colitis through Suppressing Inflammatory Cytokines in Mice.

An excessive inflammatory response of the gastrointestinal tract is recognized as one of the major contributors to ulcerative colitis (UC). Despite this, effective preventive approaches for UC remain limited. Rosmarinic acid (RA), an enriched fraction from Perilla frutescens, has been shown to exert beneficial effects on disease-related inflammatory disorders. However, RA-enriched perilla seed meal (RAPSM) and perilla seed (RAPS) extracts have not been investigated in dextran sulfate sodium (DSS)-induced UC in mice. RAPSM and RAPS were extracted using the solvent-partitioning method and analyzed with high-pressure liquid chromatography (HPLC). Mice with UC induced using 2.5% DSS for 7 days were pretreated with RAPSM and RAPS (50, 250, 500 mg/kg). Then, the clinical manifestation, colonic histopathology, and serum proinflammatory cytokines were determined. Indeed, DSS-induced UC mice exhibited colonic pathological defects including an impaired colon structure, colon length shortening, and increased serum proinflammatory cytokines. However, RAPSM and RAPS had a protective effect at all doses by attenuating colonic pathology in DSS-induced UC mice, potentially through the suppression of proinflammatory cytokines. Concentrations of 50 mg/kg of RAPSM and RAPS were sufficient to achieve a beneficial effect in UC mice. This suggests that RAPSM and RAPS have a preventive effect against DSS-induced UC, potentially through alleviating inflammatory responses and relieving severe inflammation in the colon.

Ferroptosis inhibitor improves cardiac function more effectively than inhibitors of apoptosis and necroptosis through cardiac mitochondrial protection in rats with iron-overloaded cardiomyopathy.

Iron overload cardiomyopathy (IOC) is the leading cause of death in cases of iron overload in patients. Previous studies demonstrated that iron overload led to cardiomyocyte dysfunction and death through multiple pathways including apoptosis, necroptosis and ferroptosis. However, the dominant cell death pathway in the iron-overloaded heart needs clarification. We tested the hypothesis that ferroptosis, an iron-dependent cell death, plays a dominant role in IOC, and ferroptosis inhibitor exerts greater efficacy than inhibitors of apoptosis and necroptosis on improving cardiac function in iron-overloaded rats. Iron dextran was injected intraperitoneally into male Wistar rats for four weeks to induce iron overload. Then, the rats were divided into 5 groups: treated with vehicle, apoptosis inhibitor (z-VAD-FMK), necroptosis inhibitor (Necrostatin-1), ferroptosis inhibitor (Ferrostatin-1) or iron chelator (deferoxamine) for 2 weeks. Cardiac function, mitochondrial function, apoptosis, necroptosis and ferroptosis were determined. The increased expression of apoptosis-, necroptosis- and ferroptosis-related proteins, were associated with impaired cardiac and mitochondrial function in iron-overloaded rats. All cell death inhibitors attenuated cardiac apoptosis, necroptosis and ferroptosis in iron-overloaded rats. Ferrostatin-1 was more effective than the other drugs in diminishing mitochondrial dysfunction and Bax/Bcl-2 ratio. Moreover, both Ferrostatin-1 and deferoxamine reversed iron overload-induced cardiac dysfunction as indicated by restored left ventricular ejection fraction and E/A ratio, whereas z-VAD-FMK and Necrostatin-1 only partially improved this parameter. These results indicated that ferroptosis could be the predominant form of cardiomyocyte death in IOC, and that inhibiting ferroptosis might be a potential novel treatment for IOC.

Toll-like Receptor 4 Inflammatory Perspective on Doxorubicin-Induced Cardiotoxicity.

Doxorubicin (Dox) is one of the most frequently used chemotherapeutic drugs in a variety of cancers, but Dox-induced cardiotoxicity diminishes its therapeutic efficacy. The underlying mechanisms of Dox-induced cardiotoxicity are still not fully understood. More significantly, there are no established therapeutic guidelines for Dox-induced cardiotoxicity. To date, Dox-induced cardiac inflammation is widely considered as one of the underlying mechanisms involved in Dox-induced cardiotoxicity. The Toll-like receptor 4 (TLR4) signaling pathway plays a key role in Dox-induced cardiac inflammation, and growing evidence reports that TLR4-induced cardiac inflammation is strongly linked to Dox-induced cardiotoxicity. In this review, we outline and address all the available evidence demonstrating the involvement of the TLR4 signaling pathway in different models of Dox-induced cardiotoxicity. This review also discusses the effect of the TLR4 signaling pathway on Dox-induced cardiotoxicity. Understanding the role of the TLR4 signaling pathway in Dox-induced cardiac inflammation might be beneficial for developing a potential therapeutic strategy for Dox-induced cardiotoxicity.

High Cardiorespiratory Fitness Protects against Molecular Impairments of Metabolism, Heart, and Brain with Higher Efficacy in Obesity-Induced Premature Aging.

BACKGRUOUND: High cardiorespiratory fitness (CRF) protects against age-related diseases. However, the mechanisms mediating the protective effect of high intrinsic CRF against metabolic, cardiac, and brain impairments in non-obese versus obese conditions remain incompletely understood. We aimed to identify the mechanisms through which high intrinsic CRF protects against metabolic, cardiac, and brain impairments in non-obese versus obese untrained rats. METHODS: Seven-week-old male Wistar rats were divided into two groups (n=8 per group) to receive either a normal diet or a highfat diet (HFD). At weeks 12 and 28, CRF, carbohydrate and fatty acid oxidation, cardiac function, and metabolic parameters were evaluated. At week 28, behavior tests were performed. At the end of week 28, rats were euthanized to collect heart and brain samples for molecular studies. RESULTS: The obese rats exhibited higher values for aging-related parameters than the non-obese rats, indicating that they experienced obesity-induced premature aging. High baseline CRF levels were positively correlated with several favorable metabolic, cardiac, and brain parameters at follow-up. Specifically, the protective effects of high CRF against metabolic, cardiac, and brain impairments were mediated by the modulation of body weight and composition, the lipid profile, substrate oxidation, mitochondrial function, insulin signaling, autophagy, apoptosis, inflammation, oxidative stress, cardiac function, neurogenesis, blood-brain barrier, synaptic function, accumulation of Alzheimer's disease-related proteins, and cognition. Interestingly, this effect was more obvious in HFD-fed rats. CONCLUSION: The protective effect of high CRF is mediated by the modulation of several mechanisms. These effects exhibit greater efficacy under conditions of obesity-induced premature aging.

Therapeutic potential of a single-dose melatonin in the attenuation of cardiac ischemia/reperfusion injury in prediabetic obese rats.

Although acute melatonin treatment effectively reduces cardiac ischemia/reperfusion (I/R) injury in lean rats by modulating melatonin receptor 2 (MT2), there is no information regarding the temporal effects of melatonin administration during cardiac I/R injury in prediabetic obese rats. Prediabetic obese rats induced by chronic consumption of a high-fat diet (HFD) were used. The rats underwent a cardiac I/R surgical procedure (30-min of ischemia, followed by 120-min of reperfusion) and were randomly assigned to receive either vehicle or melatonin treatment. In the melatonin group, rats were divided into 3 different subgroups: (1) pretreatment, (2) treatment during ischemic period, (3) treatment at the reperfusion onset. In the pretreatment subgroup either a nonspecific MT blocker (Luzindole) or specific MT2 blocker (4-PPDOT) was also given to the rats prior to melatonin treatment. Pretreatment with melatonin (10 mg/kg) effectively reduced cardiac I/R injury by reducing infarct size, arrhythmia, and LV dysfunction. Reduction in impaired mitochondrial function, mitochondrial dynamic balance, oxidative stress, defective autophagy, and apoptosis were observed in rats pretreated with melatonin. Unfortunately, the cardioprotective benefits were not observed when 10-mg/kg of melatonin was acutely administered to the rats after cardiac ischemia. Thus, we increased the dose of melatonin to 20 mg/kg, and it was administered to the rats during ischemia or at the onset of reperfusion. The results showed that 20-mg/kg of melatonin effectively reduced cardiac I/R injury to a similar extent to the 10-mg/kg pretreatment regimen. The MT2 blocker inhibited the protective effects of melatonin. Acute melatonin treatment during cardiac I/R injury exerted protective effects in prediabetic obese rats. However, a higher dose of melatonin is required when given after the onset of cardiac ischemia. These effects of melatonin were mainly mediated through activation of MT2.

Effectiveness of high cardiorespiratory fitness in cardiometabolic protection in prediabetic rats.

BACKGROUND: Caloric restriction and exercise are lifestyle interventions that effectively attenuate cardiometabolic impairment. However, cardioprotective effects of long-term lifestyle interventions and short-term lifestyle interventions followed by weight maintenance in prediabetes have never been compared. High cardiorespiratory fitness (CRF) has been shown to provide protection against prediabetes and cardiovascular diseases, however, the interactions between CRF, prediabetes, caloric restriction, and exercise on cardiometabolic health has never been investigated. METHODS: Seven-week-old male Wistar rats were fed with either a normal diet (ND; n = 6) or a high-fat diet (HFD; n = 30) to induce prediabetes for 12 weeks. Baseline CRF and cardiometabolic parameters were determined at this timepoint. The ND-fed rats were fed continuously with a ND for 16 more weeks. The HFD-fed rats were divided into 5 groups (n = 6/group) to receive one of the following: (1) a HFD without any intervention for 16 weeks, (2) 40% caloric restriction for 6 weeks followed by an ad libitum ND for 10 weeks, (3) 40% caloric restriction for 16 weeks, (4) a HFD plus an exercise training program for 6 weeks followed by a ND without exercise for 10 weeks, or (5) a HFD plus an exercise training program for 16 weeks. At the end of the interventions, CRF and cardiometabolic parameters were re-assessed. Then, all rats were euthanized and heart tissues were collected. RESULTS: Either short-term caloric restriction or exercise followed by weight maintenance ameliorated cardiometabolic impairment in prediabetes, as indicated by increased insulin sensitivity, improved blood lipid profile, improved mitochondrial function and oxidative phosphorylation, reduced oxidative stress and inflammation, and improved cardiac function. However, these benefits were not as effective as those of either long-term caloric restriction or exercise. Interestingly, high-level baseline CRF was correlated with favorable cardiac and metabolic profiles at follow-up in prediabetic rats, both with and without lifestyle interventions. CONCLUSIONS: Short-term lifestyle modification followed by weight maintenance improves cardiometabolic health in prediabetes. High CRF exerted protection against cardiometabolic impairment in prediabetes, both with and without lifestyle modification. These findings suggest that targeting the enhancement of CRF may contribute to the more effective treatment of prediabetes-induced cardiometabolic impairment.

Inhibition of myeloid differentiation factor 2 attenuates cardiometabolic impairments via reducing cardiac mitochondrial dysfunction, inflammation, apoptosis and ferroptosis in prediabetic rats.

Systemic inflammation is a key mediator of left ventricular dysfunction (LV) in prediabetes via the activation of myeloid differentiation factor 2 (MD2)/toll-like receptor 4 complex. The MD2 inhibitor L6H21 effectively reduced systemic and cardiac inflammation in obese mice. However, its effects on cardiac function and regulated cell death pathways in the heart in prediabetes are still unknown. The prediabetic rats were divided into 3 subgroups to receive vehicle, L6H21 (10, 20, 40 mg/kg) or metformin (300 mg/kg) for 1, 2 and 4 weeks. Then, metabolic parameters, cardiac sympathovagal balance, LV function, cardiac mitochondrial function, oxidative stress, inflammation, apoptosis, necroptosis, and ferroptosis were determined. All prediabetic rats exhibited cardiac sympathovagal imbalance, LV dysfunction, and cardiac mitochondrial dysfunction. All doses of L6H21 treatment for 2- and 4-weeks attenuated insulin resistance. L6H21 at 40 mg/kg attenuated cardiac autonomic imbalance and LV dysfunction after 1 week of treatment. Both 10 and 20 mg/kg of L6H21 required longer treatment duration to show these benefits. Mechanistically, all doses of L6H21 reduced cardiac mitochondrial dysfunction after 1 week of treatment, resulting in alleviated oxidative stress and inflammation. L6H21 also effectively suppressed cardiac apoptosis and ferroptosis, but it did not affect necroptosis in prediabetic rats. L6H21 provided the cardioprotective efficacy in dose- and time-dependent manners in prediabetic rats via reduction in apoptosis and ferroptosis.

L6H21 protects against cognitive impairment and brain pathologies via toll-like receptor 4-myeloid differentiation factor 2 signalling in prediabetic rats.

BACKGROUND AND PURPOSE: Chronic high-fat diet (HFD) intake instigates prediabetes and brain pathologies, which include cognitive decline and neuroinflammation. The myeloid differentiation factor 2 (MD-2)/toll-like receptor 4 (TLR4) complex plays a pivotal role in neuroinflammation. The MD-2 inhibitor (L6H21) reduces systemic inflammation and metabolic disturbances in HFD-induced prediabetes. However, the potential role of L6H21, and its comparison with metformin, on brain pathologies in HFD-induced prediabetes has never been investigated. EXPERIMENTAL APPROACH: Male Wistar rats were given either a normal diet (ND) (n = 8) or a HFD (n = 104) for 16 weeks. At the 13th week, ND-fed rats were given a vehicle, whereas HFD-fed rats were randomly divided into 13 subgroups. Each subgroup was given vehicle, L6H21 (three doses) or metformin (300-mg·kg-1 ·day-1 ) for 1, 2 or 4 weeks. Metabolic parameters, cognitive function, brain mitochondrial function, brain TLR4-MD-2 signalling, microglial morphology, brain oxidative stress, brain cell death and dendritic spine density were investigated. KEY RESULTS: HFD-fed rats developed prediabetes, neuroinflammation, brain pathologies and cognitive impairment. All doses of L6H21 and metformin given to HFD-fed rats at 2 and 4 weeks attenuated metabolic disturbance. CONCLUSION AND IMPLICATIONS: In rats, L6H21 and metformin restored cognition and attenuated brain pathologies dose and time-dependently. These results indicate a neuroprotective role of MD-2 inhibitor in a model of prediabetes.

Myeloid differentiation factor 2 in the heart: Bench to bedside evidence for potential clinical benefits?

Cardiac inflammation has been involved in many pathological processes in the heart including cardiac hypertrophy, fibrosis, adverse remodeling, and dysfunction. Myeloid differentiation factor 2 (MD2) is a key mediating protein that has been shown to contribute to the inflammatory process. MD2 is required for the activation of TLR4 in the form of dimerization complex. Upon activation of TLR4, the signal can be sent through either myeloid differentiation primary response protein 88 (Myd88) or toll/interleukin-1 receptor (TIR) domain-containing adaptor inducing IFN-ß (TRIF) proteins to activate the inflammatory response in cardiac tissue, after which the inflammatory cytokines and genes are produced. In patients with dilated cardiomyopathy, a positive correlation was demonstrated between the serum MD2 levels and mortality rate. Therefore, MD2 inhibition should provide beneficial effects in inflammation related to cardiac diseases such as obesity and heart failure. Multiple inhibitors of TLR4/MD2 interaction reportedly attenuated cardiac dysfunction and remodeling in animals with obesity and heart failure. In this review, we comprehensively summarized the reports from in vitro, in vivo, and clinical studies regarding the role of MD2 and the effects of MD2 inhibitors on cardiac inflammation, dysfunction, fibrosis, and remodeling. The information regarding the beneficial effects of MD2 inhibitors will be used to encourage future clinical use as a novel anti-inflammatory agent.

The effects of iron overload on mitochondrial function, mitochondrial dynamics, and ferroptosis in cardiomyocytes.

Excessive iron accumulation in the heart can lead to iron overload cardiomyopathy (IOC), the leading cause of death in hemochromatosis patients. Current understanding regarding the mechanism by which iron overload causes a deterioration in cardiac performance, mitochondrial dysfunction, and impaired mitochondrial dynamics remains limited. Ferroptosis, a newly identified form of regulated cell death, has recently been revealed influencing the pathophysiological process of IOC. Nevertheless, the direct effect of cardiac iron overload on ferroptotic cell death is incompletely characterized. This review article comprehensively summarizes and discusses the effects of iron overload on cardiac mitochondrial function, cardiac mitochondrial dynamics, ferroptosis of cardiomyocytes, and left ventricular function in in vitro and in vivo reports. This review also provides relevant consistent and controversial information which can facilitate further mechanistic investigation into iron-induced cardiac dysfunction in the clinical setting in the near future.

Combined iron chelator with N-acetylcysteine exerts the greatest effect on improving cardiac calcium homeostasis in iron-overloaded thalassemic mice.

The morbidity and mortality in thalassemia patients are predominantly caused by iron overload cardiomyopathy (IOC). Iron-induced cardiac intracellular Ca2+ ([Ca2+]i) dysregulation is among the core pathophysiological processes in IOC-related heart failure. Although cardioprotective roles of deferiprone (DFP) and N-acetylcysteine (NAC) have been reported, their effect on cardiac [Ca2+]i transients and Ca2+-regulatory protein expression in thalassemic mice is unknown. In the present study, iron overload condition was induced in wild-type (WT) and heterozygous ß-thalassemic (HT) mice by a high-iron diet. The iron-overloaded mice subsequently received a vehicle, DFP, NAC, or DFP plus NAC co-therapy. In both WT and HT iron-overloaded mice, DFP and NAC had similar efficacy in decreasing plasma non-transferrin-bound iron, decreasing cardiac iron concentration (CIC) and relieving systolic dysfunction. DFP plus NAC co-therapy, however, was better than the monotherapy in reducing CIC and restoring cardiac [Ca2+]i transient amplitude and rising rate. All regimens produced no change in cardiac Ca2+-regulatory protein expression. We provided the first evidence regarding the synergistic effect of combined iron chelator-antioxidant therapy on cardiac [Ca2+]i homeostasis in iron-overloaded thalassemic mice, with consistent improvement of cardiac contractility.