Cardioprotective Effect of Licochalcone D against Myocardial Ischemia/Reperfusion Injury in Langendorff-Perfused Rat Hearts

Increased nitric oxide availability worsens the cardiac performance during early re-perfusion period in adult rats

OBJECTIVES

Re-perfusion is the standard therapy for acute myocardial infarction, despite the associated pathologies that may contribute to irreversible myocardial injury. The present study aims to clarify the alterations in cardiac activities in response to experimental cardiac ischemic arrest followed by re-perfusion in isolated hearts perfused with nitric oxide (NO) donor, l-arginine, or NO inhibitor, Nω-Nitro-l-arginine methyl ester hydrochloride (l-NAME), to shed light on the possible role of NO in the re-perfusion process.

METHODS

Hearts isolated from adult Wistar rats were studied on Langendorff preparation under basal conditions and during 30 min re-perfusion following 30 min of total global ischemia. Rats were randomly divided into three groups; control and l-arginine or l-NAME infused heart groups. Cardiac tissue content of malondialdhyde, catalase and nitrite was also measured.

RESULTS

Compared to the control group, both l-arginine and l-NAME infused hearts showed increased basal chronotropy and myocardial flow rate. Following ischemia and during the whole period of re-perfusion, the three groups demonstrated significant deterioration in the inotropic activity and compromised myocardial flow rate. l-arginine infused hearts revealed depressed inotropy and chronotropy, weak systolic and diastolic functions with compromised myocardial flow at early 5 min of re-perfusion, yet with significantly higher myocardial flow rate by the end of re-perfusion.

CONCLUSIONS

Reducing NO availability by l-NAME revealed mild impact on the ischemia re-perfusion induced contractile dysfunction, whereas excess NO worsens cardiac performance at the early re-perfusion period.

Antioxidants and cardioprotective effects of ethyl acetate fraction of Canavalia rosea leaves in myocardial ischemia-reperfusion injury

Different degrees in the biological activities of Canavalia rosea had been previously reported . In this study, our group assessed the cardioprotective effects of the ethyl acetate fraction (EAcF) of the Canavalia rosea leaves. Firstly, it was confirmed, by in vitro approach, that the EAcF has high antioxidant properties due to the presence of important secondary metabolites, as flavonoids. In order to explore their potential protector against cardiovascular disorders, hearts were previously perfused with EAcF (300 μg.mL-1) and submitted to the global ischemia followed by reperfusion in Langendorff system. The present findings have demonstrated that EAcF restored the left ventricular developed pressure and decreased the arrhythmias severity index. Furthermore, EAcF significantly increased the glutathiones peroxidase activity with decreased malondialdehyde and creatine kinase levels. EAcF was effective upon neither the superoxide dismutase, glutationes reductase nor the catalase activities. In addition, the Western blot analysis revealed that ischemia-reperfusion injury significantly upregulates caspase 3 protein expression, while EAcF abolishes this effect. These results provide evidence that the EAcF reestablishes the cardiac contractility and prevents arrhythmias; it is suggested that EAcF could be used to reduce injury caused by cardiac reperfusion. However more clinical studies should be performed, before applying it in the clinic.

Neuroprotective Effects of Licochalcone D in Oxidative-Stress-Induced Primitive Neural Stem Cells from Parkinson's Disease Patient-Derived iPSCs

Parkinson's disease (PD) is one of the most common neurodegenerative diseases caused by the loss of dopaminergic neurons in the substantia nigra pars compacta. Although the etiology of PD is still unclear, the death of dopaminergic neurons during PD progression was revealed to be associated with abnormal aggregation of α-synuclein, elevation of oxidative stress, dysfunction of mitochondrial functions, and increased neuroinflammation. In this study, the effects of Licochalcone D (LCD) on MG132-induced neurotoxicity in primitive neural stem cells (pNSCs) derived from reprogrammed iPSCs were investigated. A cell viability assay showed that LCD had anti-apoptotic properties in MG132-induced oxidative-stressed pNSCs. It was confirmed that apoptosis was reduced in pNSCs treated with LCD through 7-AAD/Annexin Ⅴ staining and cleaved caspase3. These effects of LCD were mediated through an interaction with JunD and through the EGFR/AKT and JNK signaling pathways. These findings suggest that LCD could be a potential antioxidant reagent for preventing disease-related pathological phenotypes of PD.

Intersection of the Ubiquitin–Proteasome System with Oxidative Stress in Cardiovascular Disease

Cardiovascular diseases (CVDs) present a major social problem worldwide due to their high incidence and mortality rate. Many pathophysiological mechanisms are involved in CVDs, and oxidative stress plays a vital mediating role in most of these mechanisms. The ubiquitin–proteasome system (UPS) is the main machinery responsible for degrading cytosolic proteins in the repair system, which interacts with the mechanisms regulating endoplasmic reticulum homeostasis. Recent evidence also points to the role of UPS dysfunction in the development of CVDs. The UPS has been associated with oxidative stress and regulates reduction–oxidation homeostasis. However, the mechanisms underlying UPS-mediated oxidative stress’s contribution to CVDs are unclear, especially the role of these interactions at different disease stages. This review highlights the recent research progress on the roles of the UPS and oxidative stress, individually and in combination, in CVDs, focusing on the pathophysiology of key CVDs, including atherosclerosis, ischemia–reperfusion injury, cardiomyopathy, and heart failure. This synthesis provides new insight for continued research on the UPS–oxidative stress interaction, in turn suggesting novel targets for the treatment and prevention of CVDs.

The importance of natural chalcones in ischemic organ damage: Comprehensive and bioinformatic analysis review

Over the last few decades, extensive research has been conducted, yielding a detailed account of thousands of newly discovered compounds of natural origin and their biological activities, all of which have the potential to be used for a wide range of therapeutic purposes. There are multiple research papers denoting the central objective of chalcones, which have been shown to have therapeutic potential against various forms of ischemia. The various aspects of chalcones are discussed in this review regarding molecular mechanisms involved in the promising anti-ischemic potential of these chalcones. The main mechanisms involved in these protective effects are Nrf2/Akt activation and NF-κB/TLR4 suppression. Furthermore, in-silico studies were carried out to discover the probable binding of these chalcones to Keap-1 (an inhibitor of Nrf2), Akt, NF-κB, and TLR4 protein molecules. Besides, network pharmacology analysis was conducted to predict the interacting partners of these signals. The obtained results indicated that Nrf2, Akt, NF-κB, and TLR4 are involved in the beneficial anti-ischemic actions of chalcones. Conclusively, the present findings show that chalcones as anti-ischemic agents have a valid rationale. The discussed studies will provide a comprehensive viewpoint on chalcones and can help to optimize their effects in different ischemia. PRACTICAL APPLICATIONS: Ischemic organ damage is an unavoidable pathological condition with a high worldwide incidence. According to the current research progress, natural chalcones have been proved to treat and/or prevent various types of ischemic organ damage by alleviating oxidative stress, inflammation, and apoptosis by different molecular mechanisms. This article displays the comprehensive research progress and the molecular basis of ischemic organ damage pathophysiology and introduces natural chalcones' mechanism in the ischemic organ condition.

Ferroptosis Related Genes in Ischemic and Idiopathic Cardiomyopathy: Screening for Potential Pharmacological Targets

Background: Ferroptosis is a new form of cell death recently discovered that is distinct from apoptosis, necrosis and autophagy. This article is expected to provide a new direction for the treatment of cardiomyopathy in the future by screening potential drug targets associated with ferroptosis.

Methods: Differential expression analysis of GSE5406 from the Gene Expression Omnibus (GEO) database was performed using the GEO2R tool. Functional annotation of ferroptosis related genes was also performed. Then we constructed protein-protein interaction networks and identified hub genes using Cytoscape. The candidates for pharmacological compounds targeting the hub genes were screened by cMap.

Results: Totally 15 ferroptosis related genes (4 upregulated and 11 downregulated) for ischemic cardiomyopathy and 17 ferroptosis related genes (13 upregulated and 4 downregulated) for idiopathic cardiomyopathy were found. The biological processes involved in these genes mainly include negative regulation of apoptotic process, flavonoid metabolic process, response to drug for ischemic cardiomyopathy and cellular response to fibroblast growth factor stimulus, negative regulation of apoptotic process, and response to drug for idiopathic cardiomyopathy. KEGG results showed that these genes were mainly involved in MAPK signaling pathway for ischemic cardiomyopathy and PI3K-Akt signaling pathway for idiopathic cardiomyopathy. We generated a co-expression network for hub genes and obtained top 10 medications suggested respectively for ischemic/idiopathic cardiomyopathy.

Conclusion: Our study reveals the potential role of ferroptosis related genes in ischemic and idiopathic cardiomyopathy through bioinformatics analysis. The hub genes and potential drugs may become novel biomarkers for prognosis and precision treatment in the future.

Licochalcone D Ameliorates Oxidative Stress-Induced Senescence via AMPK Activation

Increased oxidative stress is a crucial factor for the progression of cellular senescence and aging. The present study aimed to investigate the effects of licochalcone D (Lico D) on oxidative stress-induced senescence, both in vitro and in vivo, and explore its potential mechanisms. Hydrogen peroxide (200 µM for double time) and D-galactose (D-Gal) (150 mg/kg) were used to induce oxidative stress in human bone marrow-mesenchymal stem cells (hBM-MSCs) and mice, respectively. We performed the SA-β-gal assay and evaluated the senescence markers, activation of AMPK, and autophagy. Lico D potentially reduced oxidative stress-induced senescence by upregulating AMPK-mediated activation of autophagy in hBM-MSCs. D-Gal treatment significantly increased the expression levels of senescence markers, such as p53 and p21, in the heart and hippocampal tissues, while this effect was reversed in the Lico D-treated animals. Furthermore, a significant increase in AMPK activation was observed in both tissues, while the activation of autophagy was only observed in the heart tissue. Interestingly, we found that Lico D significantly reduced the expression levels of the receptors for advanced glycation end products (RAGE) in the hippocampal tissue. Taken together, our findings highlight the antioxidant, anti-senescent, and cardioprotective effects of Lico D and suggest that the activation of AMPK and autophagy ameliorates the oxidative stress-induced senescence.

Dietary Flavonoids: Cardioprotective Potential with Antioxidant Effects and Their Pharmacokinetic, Toxicological and Therapeutic Concerns

Flavonoids comprise a large group of structurally diverse polyphenolic compounds of plant origin and are abundantly found in human diet such as fruits, vegetables, grains, tea, dairy products, red wine, etc. Major classes of flavonoids include flavonols, flavones, flavanones, flavanols, anthocyanidins, isoflavones, and chalcones. Owing to their potential health benefits and medicinal significance, flavonoids are now considered as an indispensable component in a variety of medicinal, pharmaceutical, nutraceutical, and cosmetic preparations. Moreover, flavonoids play a significant role in preventing cardiovascular diseases (CVDs), which could be mainly due to their antioxidant, antiatherogenic, and antithrombotic effects. Epidemiological and in vitro/in vivo evidence of antioxidant effects supports the cardioprotective function of dietary flavonoids. Further, the inhibition of LDL oxidation and platelet aggregation following regular consumption of food containing flavonoids and moderate consumption of red wine might protect against atherosclerosis and thrombosis. One study suggests that daily intake of 100 mg of flavonoids through the diet may reduce the risk of developing morbidity and mortality due to coronary heart disease (CHD) by approximately 10%. This review summarizes dietary flavonoids with their sources and potential health implications in CVDs including various redox-active cardioprotective (molecular) mechanisms with antioxidant effects. Pharmacokinetic (oral bioavailability, drug metabolism), toxicological, and therapeutic aspects of dietary flavonoids are also addressed herein with future directions for the discovery and development of useful drug candidates/therapeutic molecules.

Cardioprotective Effect of Echinatin Against Ischemia/Reperfusion Injury: Involvement of Hippo/Yes-Associated Protein Signaling

Background: Echinatin (Ech) has been reported to exert antioxidant and anti-inflammatory activities. In this study, we aimed to characterize the functional role of Ech in myocardial ischemic/reperfusion (MI/R) injury and elucidate its underlying mechanism of action.

Method: We established in vivo and in vitro models of MI/R injury to determine the effect of Ech on MI/R injury. Gene expression was examined using quantitative real-time polymerase chain reaction and western blotting. Myocardial infarction was assessed using tetrazolium chloride staining and the degree of myocardial injury was evaluated by measuring lactate dehydrogenase (LDH) and creatine kinase-myocardial band (CK-MB) levels. Cell apoptosis was detected using the terminal deoxynucleotidyl transfer-mediated dUTP nick end-labeling (TUNEL) assay. The viability of H9c2 cells was determined using Cell Counting Kit-8 assay.

Results: MI/R induced myocardial infarction, which was mitigated by Ech treatment. Moreover, Ech treatment resulted in a marked decline of LDH and CK-MB levels in the serum and myocardium of MI/R rats. Ech treatment also restrained cardiomyocyte apoptosis in vivo and in vitro, as evidenced by reduction in LDH release, the number of TUNEL-positive cells, and caspase-3 activity. Furthermore, Ech administration inhibited MI/R-induced activation of Hippo/Yes-associated protein signaling in vivo and in vitro, as indicated by inhibition of mammalian sterile 20-like protein kinase 1, large tumor suppressor one, and YAP phosphorylation and promotion of YAP nuclear translocation. However, silencing of YAP counteracted the protective effect of Ech on hypoxia/reoxygenation-induced myocardial injury in vitro.

Conclusion: Ech exerted its protective effect against MI/R injury at least partially by suppressing the Hippo/YAP signaling pathway, providing novel insights into the remission of MI/R injury.

MicroRNA-221/222 Mediates ADSC-Exosome-Induced Cardioprotection Against Ischemia/Reperfusion by Targeting PUMA and ETS-1

Cardiovascular disease is a major health problem in industrialized and developing countries and is the leading cause of death and disability. Myocardial ischemia/reperfusion (I/R) causes cardiomyocyte damage such as apoptosis and hypertrophy. The purpose of this study was to investigate the effects of exosomes from adipose-derived stem cells (ADSC-Exo) on hearts from I/R mice and to explore the underlying mechanisms. ADSC-Exo significantly decreased I/R-induced cardiomyocyte apoptosis and hypertrophy, as detected by TdT-mediated dUTP nick end-labeling (TUNEL) and wheat germ agglutinin (WGA) staining, respectively. In addition, the expression of apoptosis-related proteins p-p53 and PUMA and hypertrophy-related proteins ETS-1 and ANP were significantly reduced in the cardiomyocytes of ADSC-Exo-treated I/R mice compared to those of control mice. Both PUMA and ETS-1 are reported to be target genes for miR-221/222. I/R operation significantly reduced miR-221/222 expression, while ADSC-Exo treatment increased miR-221/222 expression, as detected by RT-qPCR. We also observed that cardiac I/R operation markedly increased cell apoptosis and hypertrophy in miR-221/222 knockout (KO) mice, while ADSC-Exo reduced the effects of I/R operation. Furthermore, ADSC-Exo protected H9c2 cardiomyocytes from H₂O₂-induced damage by reducing apoptosis and hypertrophy in vitro. H₂O₂ treatment significantly reduced miR-221/222 expression, while ADSC-Exo treatment reversed this effect in H9c2 cells. ADSC-Exo treatment decreased H₂O₂-induced PUMA and ETS-1 expression. Compared with control treatment, I/R treatment significantly reduced p-AKT and increased p-p65, while ADSC-Exo and miR-221/222 mimics attenuated these effects. The AKT activator SC79 and p65 inhibitor Bay 11-7082 reduced H₂O₂-induced cell apoptosis and hypertrophy. Based on these findings, ADSC-Exo prevents cardiac I/R injury through the miR-221/miR-222/PUMA/ETS-1 pathway. Therefore, ADSC-Exo is an effective inhibitor of I/R-induced heart injury.

The flavonoid-enriched extract from the root of Smilax china L. inhibits inflammatory responses via the TLR-4-mediated signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Smilax china L. has been used clinically to treat various inflammatory disorders with a long history.

AIM OF THE STUDY

To investigate the mechanisms underlying anti-inflammatory action of the extract from the herb.

MATERIALS AND METHODS

The extract was identified and quantified using the Ultra Performance Liquid Chromatography-Photo Diode Array-Mass Spectrometer method. The anti-inflammatory activities were examined in xylene-induced mouse ear edema and cotton ball-induced rat granuloma. The inflammatory mediators, pro-inflammatory cytokines and TLR-4-mediated signals in LPS-stimulated RAW264.7 macrophages were determined using ELISA, real-time PCR, Western blot and/or immunofluorescence, respectively.

RESULTS

The extract was found to enrich flavonoids (44.3%, mainly astilbin, engeletin, isoastilbin, cinchonain Ia, quercetin-3-O-a-L-rhamnopyranoside and chlorogenic acid). The flavonoid-enriched extract (FEE) inhibited xylene-induced mouse ear edema and cotton ball-induced rat granuloma, and suppressed LPS-induced over-release and/or overexpression of tumor necrosis factor-α, cyclooxygenase-2, inducible nitric oxide synthase, interleukin-1β and interleukin-6 in RAW264.7 macrophages. Mechanistically, FEE suppressed protein overexpression of TLR-4 and its downstream signals, MyD88 protein, phosphorylated inhibitory κB-α, NF-κB-P65 and MAPK p38, as well as phosphorylation of phosphoinositide 3-kinase (PI3K) p85α at Tyr⁶⁰⁷ and Akt at Ser⁴⁷³ in LPS-stimulated macrophages. The mode of the anti-inflammatory action of FEE was similar to that of TAK-242 (a selective TLR-4 inhibitor).

CONCLUSIONS

The present results demonstrate that FEE inhibit inflammatory responses via the TLR-4-mediated signaling pathway. Our findings go a new insight into the mechanisms underlying anti-inflammatory action of the herb, and provide a better understanding of its use for inflammatory diseases.

Licochalcone D Induces ROS-Dependent Apoptosis in Gefitinib-Sensitive or Resistant Lung Cancer Cells by Targeting EGFR and MET

Licochalcone D (LCD), a flavonoid isolated from a Chinese medicinal plant Glycyrrhiza inflata, has a variety of pharmacological activities. However, the anti-cancer effects of LCD on non-small cell lung cancer (NSCLC) have not been investigated yet. The amplification of MET (hepatocyte growth factor receptor) compensates for the inhibition of epidermal growth factor receptor (EGFR) activity due to tyrosine kinase inhibitor (TKI), leading to TKI resistance. Therefore, EGFR and MET can be attractive targets for lung cancer. We investigated the anti-proliferative and apoptotic effects of LCD in lung cancer cells HCC827 (gefitinib-sensitive) and HCC827GR (gefitinib-resistant) through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, pull-down/kinase assay, cell cycle analysis, Annexin-V/7-ADD staining, reactive oxygen species (ROS) assay, mitochondrial membrane potential (MMP) assay, multi-caspase assay, and Western blot analysis. The results showed that LCD inhibited phosphorylation and the kinase activity of EGFR and MET. In addition, the predicted pose of LCD was competitively located at the ATP binding site. LCD suppressed lung cancer cells growth by blocking cell cycle progression at the G2/M transition and inducing apoptosis. LCD also induced caspases activation and poly (ADP-ribose) polymerase (PARP) cleavage, thus displaying features of apoptotic signals. These results provide evidence that LCD has anti-tumor effects by inhibiting EGFR and MET activities and inducing ROS-dependent apoptosis in NSCLC, suggesting that LCD has the potential to treat lung cancer.

Biological Effects of Licochalcones

Medicinal plants and their natural bioactive molecules, are evaluated as the foundation for health preservation and care of humanity. The licorice root, known as "Radix Glycyrrhizae", is a perennial plant that comes from Mediterranean countries, central to southern Russia, Asia, Turkey, Iraq and Iran. The licorice root has been used in traditional Chinese medicines for centuries and has been defined as "the progenitor of herbs". The name 'Licorice' is derived from the ancient Greek word Glukurrhiza, meaning 'sweet root'. It consists of approximately 30 species, however, the most common ones consist of Glycyrrhiza glabra L., Glycyrrhiza uralensis Fisch and Glycyrrhiza Inflata. In addition, the licorice root contains chalcones, which are a part of an important class of natural products and are precursors of flavonoids. Chemically, chalcones are composed of two aromatic rings associated with α, β-unsaturated α-carbon ketone, representing the prima nucleus of the structure. They have been classified, according to chemical structures, in Licochalcone A, B, C, D, E, F and G. This review aims to highlight all the in vitro and in vivo studies that have been conducted on the licochalcones, extracted from Glycyrrhiza species. The main effects are as follows: anti-inflammatory, antioxidant, anticancer, antimicrobial, antiviral, antiallergic, antidiabetic, hepatotoxic and osteogenic. It is important to implement the introduction of biologically active natural molecules from the bench (research) to the bedside (clinical practice). However, in the future, it is required to conduct additional studies to validate these biological effects.

Dietary Polyphenol Intake, Blood Pressure, and Hypertension: A Systematic Review and Meta-Analysis of Observational Studies

Background: Dietary polyphenols, including flavonoids, have been the focus of major recent attentions due to their wide content in a variety of foods commonly consumed and the findings from numerous studies showing evidence of an association with positive outcomes on human health. Methods: A systematic search using electronic databases PubMed and EMBASE was performed to retrieve English language studies published from the earliest indexing year of each database to April 2019, reporting on the association between dietary flavonoids intake and hypertension. Results: The search strategy resulted in the final selection of 20 studies including 15 cross-sectional investigations and 7 prospective cohorts (1 study reported on 3 prospective cohorts). 5 prospective cohorts, comprising 200,256 individuals and 45,732 cases of hypertension were included in the quantitative analysis. Analysis by extreme quantiles of intake of flavonoid showed a non-significant association with decreased risk of hypertension (RR (risk ratio): 0.96, 95% CI (confidence interval): 0.89, 1.03). Taking into consideration individual flavonoid subclasses, dietary anthocyanins intake was associated with 8% reduction in risk of hypertension, when comparing highest vs. lowest exposure (RR: 0.92, 95% CI: 0.88, 0.97). Conclusions: Further studies are needed to strengthen the retrieved association between anthocyanins consumption and decreased risk of hypertension and clarify whether total flavonoids or rather individual subclasses may exert beneficial effects on blood pressure.

Exploring the putative role of TRPV1 -dependent CGRP release in remote hind preconditioning-induced cardioprotection

BACKGROUND

Remote ischemic preconditioning (RIPC) is a phenomenon whereby transient nonlethal ischemia and reperfusion episodes confer protection against prolonged ischemia reperfusion-induced injury. However, the underlying intracellular signaling has not been extensively explored.

OBJECTIVE

This study aimed to inspect the putative involvement of TRPV₁ -dependent CGRP release in mediating remote hind limb preconditioning-induced cardioprotection.

METHODS

In this study, remote hind limb preconditioning stimulus was delivered (four consecutive episodes of 5 minutes of ischemia reperfusion) using a blood pressure cuff tied at the inguinal level of the rat. The isolated rat hearts were perfused on the Langendorff's system and were subjected to 30-minutes global ischemia and 120-minutes reperfusion. Prolonged ischemia and subsequent reperfusion led to myocardial injury that was evaluated in terms of infarct size, LDH release, CK release, LVDP, +dp/dt_max , -dp/dt_min , and coronary flow rate. The pharmacological agents used in this study included capsaicin as TRPV₁ channel activator, sumatriptan and CGRP8-37 as CGRP blockers.

RESULTS

Remote hind limb and capsaicin preconditioning (10 mg/kg^-1 ) significantly reduced the infarct size, LDH release, CK release and significantly improved LVDP, +dp/dt_max , -dp/dt_min , and coronary flow rate. However, remote hind limb and capsaicin preconditioning-induced cardioprotective effects were remarkably reduced in the presence of sumatriptan (8 mg/kg^-1 ) and CGRP8-37 (1 mg/kg^-1 ).

CONCLUSION

This indicates that remote hind limb preconditioning stimulus probably activates TRPV₁ channels which subsequently induces CGRP release to produce cardioprotective effects.

Luteoloside attenuates anoxia/reoxygenation-induced cardiomyocytes injury via mitochondrial pathway mediated by 14-3-3η protein

Ischemia/reperfusion (I/R) injury is the major cause of acute cardiovascular disease worldwide. 14-3-3η protein has been demonstrated to protect myocardium against I/R injury. Luteoloside (Lut), a flavonoid found in many Chinese herbs, exerts myocardial protection effects. However, the mechanism remains unclear. We hypothesize that the cardioprotective role of Lut is exerted by regulating the 14-3-3η signal pathway. To investigate our hypothesis, an in vitro I/R model was generated in H9C2 cardiomyocytes by anoxia/reoxygenation (A/R) treatment. The effects of Lut on cardiomyocytes with A/R injury were assessed by determining the cell viability, lactate dehydrogenase levels, intracellular reactive oxygen species levels, mitochondrial permeability transition pores (mPTP) openness, caspase-3 activity, and apoptosis rate. The effects on protein expression were tested using western blot analysis. Lut attenuated A/R-induced injury to cardiomyocytes by increasing the expression of 14-3-3η protein and cell viability; decreasing levels of lactate dehydrogenase, reactive oxygen species, mPTP openness, caspase-3 activity, and low apoptosis rate were observed. However, the cardioprotective effects of Lut were blocked by AD14-3-3ηRNAi, an adenovirus knocking down the intracellular 14-3-3η expression. In conclusion, to our knowledge, this is the first study to demonstrate that Lut protected cardiomyocytes from A/R-induced injury via the regulation of 14-3-3η signaling pathway.

Flavonoids, Dairy Foods, and Cardiovascular and Metabolic Health: A Review of Emerging Biologic Pathways

A growing body of nutritional science highlights the complex mechanisms and pleiotropic pathways of cardiometabolic effects of different foods. Among these, some of the most exciting advances are occurring in the area of flavonoids, bioactive phytochemicals found in plant foods; and in the area of dairy, including milk, yogurt, and cheese. Many of the relevant ingredients and mechanistic pathways are now being clarified, shedding new light on both the ingredients and the pathways for how diet influences health and well-being. Flavonoids, for example, have effects on skeletal muscle, adipocytes, liver, and pancreas, and myocardial, renal, and immune cells, for instance, related to 5'-monophosphate-activated protein kinase phosphorylation, endothelial NO synthase activation, and suppression of NF-κB (nuclear factor-κB) and TLR4 (toll-like receptor 4). Effects of dairy are similarly complex and may be mediated by specific amino acids, medium-chain and odd-chain saturated fats, unsaturated fats, branched-chain fats, natural trans fats, probiotics, vitamin K1/K2, and calcium, as well as by processing such as fermentation and homogenization. These characteristics of dairy foods influence diverse pathways including related to mammalian target of rapamycin, silent information regulator transcript-1, angiotensin-converting enzyme, peroxisome proliferator-activated receptors, osteocalcin, matrix glutamate protein, hepatic de novo lipogenesis, hepatic and adipose fatty acid oxidation and inflammation, and gut microbiome interactions such as intestinal integrity and endotoxemia. The complexity of these emerging pathways and corresponding biological responses highlights the rapid advances in nutritional science and the continued need to generate robust empirical evidence on the mechanistic and clinical effects of specific foods.

Proteasome and Organs Ischemia-Reperfusion Injury

The treatment of organ failure on patients requires the transplantation of functional organs, from donors. Over time, the methodology of transplantation was improved by the development of organ preservation solutions. The storage of organs in preservation solutions is followed by the ischemia of the organ, resulting in a shortage of oxygen and nutrients, which damage the tissues. When the organ is ready for the transplantation, the reperfusion of the organ induces an increase of the oxidative stress, endoplasmic reticulum stress, and inflammation which causes tissue damage, resulting in a decrease of the transplantation success. However, the addition of proteasome inhibitor in the preservation solution alleviated the injuries due to the ischemia-reperfusion process. The proteasome is a protein structure involved in the regulation the inflammation and the clearance of damaged proteins. The goal of this review is to summarize the role of the proteasome and pharmacological compounds that regulate the proteasome in protecting the organs from the ischemia-reperfusion injury.

Myrtenol protects against myocardial ischemia-reperfusion injury through antioxidant and anti-apoptotic dependent mechanisms

Myrtenol is a monoterpene with multiple pharmacological activities. However, although monoterpenes have been proposed to play beneficial roles in a variety of cardiac disorders, pharmacological actions of myrtenol in the heart are not yet reported. Hence, the aim of this study was to evaluate whether myrtenol promotes cardioprotection against myocardial ischemia-reperfusion (IR) injury, and the mechanisms involved in these effects. Male Wistar rats were orally treated for seven consecutive days with myrtenol (50 mg/kg) or N-acetyl cysteine (1.200 mg/kg, NAC). Afterward, hearts were subjected to myocardial IR injury. Here, we show that the severe impairment of contractile performance induced by IR was significantly prevented by myrtenol or NAC. Moreover, myrtenol abolished aberrant electrocardiographic waveform (ST-segment elevation), as well as reduced life-threatening arrhythmias and infarct size induced by IR injury. Importantly, myrtenol fully prevented the massive increase of cardiac reactive oxygen species generation and oxidative stress damage. Accordingly, myrtenol restored the impairment of endogenous antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase and reductase) activities and balance of pro- and anti-apoptotic pathways (Bax and Bcl-2), associated with decreased apoptotic cells. Taken together, our data show that myrtenol promotes cardioprotection against IR injury through attenuation of oxidative stress and inhibition of pro-apoptotic pathway.

Caffeoylxanthiazonoside exerts cardioprotective effects during chronic heart failure via inhibition of inflammatory responses in cardiac cells

Caffeoylxanthiazonoside (CYT) is an active constituent isolated from the fruit of the Xanthium strumarium L plant. The aim of the present study was to investigate the cardioprotective effects of oral administration of CYT on chronic heart failure (CHF) and its underlying mechanisms. A rat model of CHF was first established, and cardiac function indices, including the heart/body weight index, left heart/body weight index, fractional shortening (FS), ejection fraction (EF), cardiac output (CO) and heart rate (HR), were subsequently determined by cardiac ultrasound. Serum levels of lactate dehydrogenase (LDH) and creatine kinase (CK), and the levels of pro-inflammatory cytokines, including tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-1β in heart tissues and cardiac microvascular endothelial cells (CMECs) were determined using ELISA. In addition, the protein expression levels of nuclear factor-κB (NF-κB) signaling pathway members were determined by western blotting in CMECs. The results demonstrated that oral administration of 10, 20, 40 mg/kg CYT significantly reduced cardiac hypertrophy and reversed FS, EF, CO and HR when compared with CHF model rats. In addition, CYT administration significantly decreased the levels of TNF-α, IL-6 and IL-1β in heart tissues, as well as serum LDH and CK levels. Furthermore, exposure of CMECs to 20, 40 and 80 µg/ml CYT significantly decreased the production of TNF-α, IL-1β and IL-6. The protein expression levels of cytoplasmic NF-κB p65 and IκB were upregulated, while nuclear NF-κB p65 was downregulated following treatment of CMECs with 20, 40 and 80 µg/ml CYT when compared with untreated CHF model controls. In conclusion, the results of the current study suggest that CYT demonstrates cardioprotective effects in CHF model rats by suppressing the expression of pro-inflammatory cytokines and the NF-κB signaling pathway.

Down-regulation of lncRNA KCNQ1OT1 protects against myocardial ischemia/reperfusion injury following acute myocardial infarction

This study aimed to investigate the protective effects of long non-coding RNA KCNQ1OT1 against myocardial ischemia/reperfusion (I/R) injury following acute myocardial infarction, as well as its regulatory mechanism. We used the cardiac muscle H9c2 cells under condition of oxygen glucose deprivation followed by reperfusion (OGD/R) to induce myocardial I/R injury. Then H9C2 cells were transfected with si-NC, si-KCNQ1OT1, pc-NC, pc-KCNQ1OT1, si-AdipoR1 and si-AdipoR2, respectively. The myocardial cell viability and apoptosis were respectively detected. In addition, the expression levels of inflammatory factors, apoptosis-related proteins and p38 MAPK/NF-κB pathway-related proteins were detected. Besides, an inhibitor of p38 MAPK/NF-κB pathway SB203580 was used to treat cells to verify the relationship between KCNQ1OT1 and p38 MAPK/NF-κB pathway. The expression of KCNQ1OT1 was significantly up-regulated in OGD/R-induced myocardial H9C2 cells. The OGD/R-induced decreased cell viability and AdipoR1 expression could be reversed after suppression of KCNQ1OT1. In addition, suppression of KCNQ1OT1 reduced OGD/R-induced increased expressions of TNF-α, IL-6 and IL-1β and OGD/R-induced increased cell apoptosis, which were reversed after knockdown of AdipoR1. Besides, suppression of KCNQ1OT1 significantly down-regulated the OGD/R-induced increased expression of p-p38 and p-NF-κB, which were also reversed after knockdown of AdipoR1. Moreover, SB203580, an inhibitor of p38 MAPK/NF-κB signal pathway, could further enhance the inhibitory effects of KCNQ1OT1 suppression on the expression of p-p38, TNF-α, IL-6, IL-1β and p-NF-κB in OGD/R-induced myocardial H9C2 cells. Suppression of KCNQ1OT1 may prevent myocardial I/R injury following acute myocardial infarction via regulating AdipoR1 and involving in p38 MAPK/NF-κB signal pathway.

High mobility group box 1 protein attenuates myocardial ischemia reperfusion injury via inhibition of the p38 mitogen-activated protein kinase signaling pathway

The present study aimed to determine the effects of high mobility group box 1 protein (HMGB1) on myocardial ischemia reperfusion (I/R) injury in rats following acute myocardial ischemia and investigate the underlying molecular mechanisms of these effects. Male Wistar rats were randomly divided into the following groups (n=10/group): Sham operation; I/R; HMGB50 (50 ng/kg HMGB1 before I/R); HMGB100 (100 ng/kg HMGB1 before I/R); and HMGB200 (200 ng/kg HMGB1 before I/R). Serum cardiac troponin I (cTnI), interleukin (IL)-6 and tumor necrosis factor (TNF)-α levels were subsequently measured. Myocardial levels of malondialdehyde (MDA) and superoxide dismutase (SOD) were also determined. Myocardial infarction size (IS) was determined by 2,3,5-triphenyltetrazolium chloride staining. Myocardial expression of hypoxia inducible factor (HIF)-1α and phosphorylated p38 mitogen-activated protein kinase (P-p38 MAPK) protein was measured using western blotting. The results demonstrated that HMGB1 significantly decreased serum levels of cTnI, IL-6 and TNF-α and myocardial IS in I/R rats compared with the sham group (all P<0.05). HMGB1 also significantly decreased and increased myocardial levels of MDA and SOD, respectively (both P<0.05). HMGB1 significantly increased myocardial expression of HIF-1α and decreased expression of P-p38 MAPK following I/R (both P<0.05). These effects of HMGB1 occurred in a dose-dependent manner. The results of the current study indicate that the cardioprotective effects of intravenous HMGB1 are associated with increased myocardial expression of HIF-1α via inhibition of P-p38 MAPK expression, leading to inhibition of the P-p38 MAPK signaling pathway.

Effects of Polyphenols on Oxidative Stress-Mediated Injury in Cardiomyocytes

Cardiovascular diseases are the main cause of mortality and morbidity in the world. Hypertension, ischemia/reperfusion, diabetes and anti-cancer drugs contribute to heart failure through oxidative and nitrosative stresses which cause cardiomyocytes nuclear and mitochondrial DNA damage, denaturation of intracellular proteins, lipid peroxidation and inflammation. Oxidative or nitrosative stress-mediated injury lead to cardiomyocytes apoptosis or necrosis. The reactive oxygen (ROS) and nitrogen species (RNS) concentration is dependent on their production and on the expression and activity of anti-oxidant enzymes. Polyphenols are a large group of natural compounds ubiquitously expressed in plants, and epidemiological studies have shown associations between a diet rich in polyphenols and the prevention of various ROS-mediated human diseases. Polyphenols reduce cardiomyocytes damage, necrosis, apoptosis, infarct size and improve cardiac function by decreasing oxidative stress-induced production of ROS or RNS. These effects are achieved by the ability of polyphenols to modulate the expression and activity of anti-oxidant enzymes and several signaling pathways involved in cells survival. This report reviews current knowledge on the potential anti-oxidative effects of polyphenols to control the cardiotoxicity induced by ROS and RNS stress.

Cardioprotection provided by Echinatin against ischemia/reperfusion in isolated rat hearts

Background

This study evaluated the protective effect of Echinatin against myocardial ischemia/reperfusion (I/R) injury in rats.

Methods

The effect of Echinatin on cardiac function in rats subjected to I/R was demonstrated through improved Langendorff retrograde perfusion technology. Adult Sprague–Dawley rats were randomly divided into five groups, and myocardial infarct size was macroscopically estimated through 2,3,5-triphenyltetrazolium chloride staining. The coronary effluent was analyzed for the release of lactate dehydrogenase (LDH) and creatine kinase (CK) to assess the degree of cardiac injury. The concentrations of malondialdehyde (MDA), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) were determined along with superoxide dismutase (SOD) activity using ELISA. Finally, cardiomyocyte apoptosis analysis was conducted with POD, an in situ cell death detection kit.

Results

Echinatin (0.5 and 2.5 μg/mL) pretreatment enhanced the maximum up/down rate of the left ventricular pressure (±dp/dtmax), improved the heart rate, increased the left ventricular developed pressure (LVDP), enhanced the coronary flow, and reduced the CK and LDH levels in the coronary flow of the treated group compared with the I/R group. Echinatin limited the contents of CK and LDH, improved the LVDP, reduced the contents of MDA, IL-6, and TNF-α, and increased the SOD activity. The infarct size and cell apoptosis in the hearts of the rats in the Echinatin-treated group were smaller and lower, respectively, than those in the hearts of the rats in the I/R control group.

Conclusion

Echinatin exerts a protective effect against I/R-induced myocardial injury on hearts. This effect may be attributed to the antioxidant and anti-inflammatory activities of this compound.

Apigenin attenuates myocardial ischemia/reperfusion injury via the inactivation of p38 mitogen‑activated protein kinase

Apigenin (Api) is a plant monomer associated with reducing the risk of heart disease. However, the mechanism of action remains to be fully elucidated. In the present study, it was hypothesized that API has cardioprotective effects by attenuating myocardial ischemia/reperfusion (I/R) injury. Rats were randomly subjected to sham operation, myocardial I/R alone or I/R + Api. Cardiac function was measured, and infarct size was evaluated by triphenyltetrazolium chloride staining following reperfusion. The myocardial enzyme leakage was analyzed for lactate dehydrogenase (LDH) and creatine kinase (CK). The myocardium was also assessed for total superoxide dismutase (SOD) activity and malondialdehyde (MDA) content. The phosphorylation of p38 mitogen‑activated protein kinase (MAPK) was analyzed by western blotting. The present study reported for the first time, to the best of our knowledge, that I/R significantly increased infarct size, induced CK and LDH release, inhibited the activity of SOD and increased the levels of MDA, all of which were prevented by treatment with Api. In addition, I/R increased the phosphorylation of p38 MAPK, which was significantly decreased in the Api‑treated heart tissue samples following I/R, compared with the untreated heart tissue samples. In conclusion, the results of the present study demonstrated that Api inhibited the p38 MAPK signaling pathway to protect cardiomyocytes from I/R‑induced injury.