Novel therapeutic strategies for ischemic heart disease

Progress of nanomaterials in the treatment of ischemic heart disease

Medical or surgical interventions are commonly used to alleviate the clinical symptoms of individuals suffering from ischemic heart disease (IHD), but global morbidity and mortality remain high. This is due to the complexity of disease progression and the pathological basis of IHD, which primarily includes myocardial infarction (MI), myocardial ischemia-reperfusion injury (IRI), and heart failure (HF), as well as underlying mechanisms, such as mitochondrial damage, inflammation, oxidative stress, and cardiomyocyte death. However, many drugs have limitations, such as poor stability and low bioavailability, and surgical strategies are often ineffective in preventing disease recurrence. To overcome these problems, it is necessary to develop effective drug delivery systems and technologies. Due to their advantages in enhancing drug utilization, nanomaterials are being used to control drug biodistribution and achieve targeted accumulation, addressing the therapeutic needs of IHD. In this work, we first described the clinical aspects of MI, IRI, and HF in the context of IHD as well as their shared pathological origins. Next, clinical interventional procedures for IHD are summarized. Finally, recent developments in the use of nanomaterials for the treatment of MI, IRI, and HF are highlighted, along with potential directions for future research.

Cardioprotective potential of oleuropein, hydroxytyrosol, oleocanthal and their combination: Unravelling complementary effects on acute myocardial infarction and metabolic syndrome

Clinical studies have previously established the role of olive products in cardiovascular disease (CVD) prevention, whilst the identification of the responsible constituents for the beneficial effects is still pending. We sought to assess and compare the cardioprotective potential of oleuropein (OL), hydroxytyrosol (HT), oleocanthal (OC) and oleanolic Acid (OA), regarding Ischemia/Reperfusion Injury (IRI) and CVD risk factors alleviation. The scope of the study was to design a potent and safe combinatorial therapy for high-cardiovascular-risk patients on a bench-to-bedside approach. We evaluated the IRI-limiting potential of 6-weeks treatment with OL, HT, OC or OA at nutritional doses, in healthy and metabolic syndrome (MS)-burdened mice. Three combinatorial regimens were designed and the mixture with preponderant benefits (OL-HT-OC, Combo 2), including infarct sparing and antiglycemic potency, compared to the isolated compounds, was further investigated for its anti-atherosclerotic effects. In vivo experiments revealed that the combination regimen of Combo 2 presented the most favorable effects in limiting infarct size and hyperglycemia, which was selected to be further investigated in the clinical setting in Chronic Coronary Artery Syndrome (CCAS) patients. Cardiac function, inflammation markers and oxidative stress were assessed at baseline and after 4 weeks of treatment with the OL-HT-OC supplement in the clinical study. We found that OL, OC and OA significantly reduced infarct size in vivo compared to Controls. OL exhibited antihyperglycemic properties and OA attenuated hypercholesterolemia. OL-HT-OA, OL-HT-OC and OL-HT-OC-OA combination regimens were cardioprotective, whereas only OL-HT-OC mitigated hyperglycemia. Combo 2 cardioprotection was attributed to apoptosis suppression, enhanced antioxidant effects and upregulation of antioxidant enzymes. Additionally, it reduced atherosclerotic plaque extent in vivo. OL-HT-OC supplement ameliorated cardiac, vascular and endothelial function in the small-scale clinical study. Conclusively, OL-HT-OC combination therapy exerts potent cardioprotective, antihyperglycemic and anti-atherosclerotic properties in vivo, with remarkable and clinically translatable cardiovascular benefits in high-risk patients.

DJ-1: Potential target for treatment of myocardial ischemia-reperfusion injury

Ischemic heart disease (IHD) is a significant global health concern, resulting in high rates of mortality and disability among patients. Although coronary blood flow reperfusion is a key treatment for IHD, it often leads to acute myocardial ischemia-reperfusion injury (IRI). Current intervention strategies have limitations in providing adequate protection for the ischemic myocardium. DJ-1, originally known as a Parkinson's disease related protein, is a highly conserved cytoprotective protein. It is involved in enhancing mitochondrial function, scavenging reactive oxygen species (ROS), regulating autophagy, inhibiting apoptosis, modulating anaerobic metabolism, and exerting anti-inflammatory effects. DJ-1 is also required for protective strategies, such as ischemic preconditioning, ischemic postconditioning, remote ischemic preconditioning and pharmacological conditioning. Therefore, DJ-1 emerges as a potential target for the treatment of myocardial IRI. Our comprehensive review delves into its protective mechanisms in myocardial IRI and the structural foundations underlying its functions.

Inhibition of the protective effects of preconditioning in ischemia-reperfusion injury by chronic methadone: the role of pAkt and pSTAT3

Cardiac ischemic preconditioning (Pre) reduces cardiac ischemia-reperfusion injury (IRI) by stimulating opioid receptors. Chronic use of opioids can alter the signaling pathways. We investigated the effects of chronic methadone use on IRI and Pre. The experiments were performed on isolated hearts of male Wistar rats in four groups: IRI, Methadone + IRI (M-IRI), Pre + IRI (Pre-IRI), Methadone + Pre + IRI (M-Pre-IRI). The infarct size (IS) in the Pre-IRI group was smaller than the IRI group (26.8% vs. 47.8%, P < 0.05). In the M-IRI and M-Pre-IRI groups, the infarct size was similar to the IRI group. Akt (Ak strain transforming) phosphorylation in the Pre-IRI, M-IRI, and M-Pre-IRI groups was significantly higher than in the IRI group (0.56 ± 0.15, 0.63 ± 0.20, and 0.93 ± 0.18 vs 0.28 ± 0.17 respectively). STAT3 (signal transducer and activator of transcription 3) phosphorylation in the Pre-IRI and M-Pre-IRI groups (1.38 ± 0.14 and 1.46 ± 0.33) was significantly higher than the IRI and M-IRI groups (0.99 ± 0.1 and 0.98 ± 0.2). Thus, chronic use of methadone not only has no protective effect against IRI but also destroys the protective effects of ischemic preconditioning. This may be due to the hyperactivation of Akt and changes in signaling pathways.

Exploring the pharmacological versatility of ficus carica: Modulating classical immunometabolism and beyond

The burden of metabolic disorders is alarmingly increasing globally. On the other hand, sustainability is the key project of the 21st century. Natural products offer a coherent option for the complementary management of both these challenges. Ficus carica (FC), commonly known as the fig fruit, has an experimentally proven potency for the modulation of cell cycle, immunity, inflammation, metabolism, and oxidative stress. Here, we review the potential of FC-derived products (FCDP) in slowing down the progression of cancers, acute/chronic inflammation-related conditions, infections, metabolic disorders, toxicities, neurological and neuromuscular diseases, gastrointestinal disorders, vascular diseases, and skin-stressing conditions, as well as, in boosting normal healthy functions of the endocrine, immune, metabolic, and nervous systems. It reveals a variety of cellular and molecular targets for FCDP: cytokines (TNF-α, IL-1β, IL-6, IL-10, IL-12, IL-18, IFN-γ), chemokines (CCL2), other inflammatory mediators (CRP, PGE2), immune receptors (TLR-2, TLR-4, FcεRI), oxidative stress-related markers (SOD, GSH, MDA, GPx, catalase, ROS, NO, protein carbonyls), kinases (MAPKs, hexokinase, G6Pase, FBPase, PEPCK, Akt, AMPK, GSK3, CDKs), other enzymes (COX-2, iNOS, MMPs, caspases), growth factors/receptors (VEGF, EGFR), hormones (DHEAS, prolactin, GnRH, FSH, LH, estradiol, DHT, insulin), cell death-related markers (Bcl-2, Bax, Bak, FasL, gasdermins, cytochrome C), glucose transporter protein (Glut4), and transcription factors (NF-κB, HNF-4α, Foxo, PGC-1α, PPAR-γ, C/EBP-α, CREB, NFATC1, STAT3). FCDP cause both activation and inhibition of AMPK, MAPK, and NF-κB signaling to confer condition-specific advantages. Such a broad-range activity might be attributed to different mechanisms of action of FCDP in modulating functions within the classical immunometabolic system, but also beyond.

Ozone pretreatment alleviates ischemiareperfusion injury-induced myocardial ferroptosis by activating the Nrf2/Slc7a11/Gpx4 axis

Myocardial ischemiareperfusion injury (MIRI) is defined as the additional damage that occurs during the process of restoring blood flow to the heart tissue after ischemia-induced damage. Ozone is a powerful oxidizer, but low concentrations of ozone can protect various organs from oxidative stress. Some studies have demonstrated a link between ozone and myocardioprotection, but the mechanism remains unclear. To establish an in vivo animal model of ischemiareperfusion injury (I/R), this study utilized C57 mice, while an in vitro model of hypoxia-reoxygenation (H/R) injury was developed using H9c2 cardiomyocytes to simulate ischemiareperfusion injury. Ozone pretreatment was used in in vitro and in vivo experiments. Through this research, we found that ozone therapy can reduce myocardial injury, and further studies found that ozone regulates the expression levels of these ferroptosis-related proteins and transcription factors in the H/R model, which were screened by bioinformatics. In particular, nuclear translocation of Nrf2 was enhanced by pretreatment with ozone, inhibited ferroptosis and ameliorated oxidative stress by initiating the expression of Slc7a11 and Gpx4. Significantly, Nrf2 gene silencing reverses the protective effects of ozone in the H/R model. In summary, our results suggest that ozone protects the myocardium from I/R damage through the Nrf2/Slc7a11/Gpx4 signaling pathway, highlighting the potential of ozone as a new coronary artery disease therapy.

Effect of tanshinone IIA for myocardial ischemia/reperfusion injury in animal model: preclinical evidence and possible mechanisms

Introduction: Tanshinone IIA (Tan IIA), the major active lipophilic ingredient of Radix Salviae Miltiorrhizae, exerts various therapeutic effects on the cardiovascular system. We aimed to identify the preclinical evidence and possible mechanisms of Tan IIA as a cardioprotective agent in the treatment of myocardial ischemia/reperfusion injury. Methods: The study quality scores of twenty-eight eligible studies and data analyses were separately assessed using the CAMARADES 10-item checklist and Rev-Man 5.3 software. Results: The study quality score ranged from 3/10 to 7/10 points. The present study provided preliminary preclinical evidence that Tan IIA could significantly decrease the myocardial infarct size, cardiac enzyme activity and troponin levels compared with those in the control group (p < 0.05). Discussion: Tan IIA alleviated myocardial I/R injury via antioxidant, anti-inflammatory, anti-apoptosis mechanisms and improved circulation and energy metabolism. Thus, Tan IIA is a promising cardioprotective agent for the treatment of myocardial ischemia/reperfusion injury and should be further investigated in clinical trials.

Self-care in coronary heart disease patient and caregiver dyads (HEARTS-IN-DYADS)-Protocol of a multicenter longitudinal study

Self-care performed by patients and the caregiver contribution to this self-care are essential for improving cardiovascular outcomes; however, so far, no studies have sufficiently investigated this field in Italy. This paper describes a research protocol of a multi-center longitudinal study designed to investigate the self-care of patients affected by coronary heart disease (CHD), the caregiver's contribution to this self-care, the predictors of patient and caregiver self-care, the mediating role of self-efficacy, and the self-care outcomes. Data collection will be performed across seven Italian inpatient settings at baseline and 3 and 6 months from enrollment. Multilevel modeling and actor partner interdependence models will be implemented on a sample of 330 patient-caregiver dyads to adjust for the interdependence of measurements. The study received approval from an ethics committee in Italy and was financed in January 2021 by a grant from the Solidal Foundation in Alessandria. This research will advance the knowledge about the self-care process in CHD. The results will guide research and clinical practice by identifying variables sensitive to educational interventions.

Protective effects of curcumin on ischemia/reperfusion injury

Ischemia/reperfusion (I/R) injury is a term used to describe phenomena connected to the dysfunction of various tissue damage due to reperfusion after ischemic injury. While I/R may result in systemic inflammatory response syndrome or multiple organ dysfunction syndrome, there is still a long way to improve therapeutic outcomes. A number of cellular metabolic and ultrastructural alterations occur by prolonged ischemia. Ischemia increases the expression of proinflammatory gene products and bioactive substances within the endothelium, such as cytokines, leukocytes, and adhesion molecules, even as suppressing the expression of other "protective" gene products and substances, such as thrombomodulin and constitutive nitric oxide synthase (e.g., prostacyclin, nitric oxide [NO]). Curcumin is the primary phenolic pigment derived from turmeric, the powdered rhizome of Curcuma longa. Numerous studies have shown that curcumin has strong antiinflammatory and antioxidant characteristics. It also prevents lipid peroxidation and scavenges free radicals like superoxide anion, singlet oxygen, NO, and hydroxyl. In our study, we highlight the mechanisms of protective effects of curcumin against I/R injury in various organs.

Interaction of Medicinal Plants and Their Active Constituents With Potassium Ion Channels: A Systematic Review

Potassium ion (K⁺) channels are pore-forming transmembrane proteins that control the transport of K⁺ ions. Medicinal plants are widely used as complementary therapies for several disorders. Studies have shown that the modulation of K⁺ channels is most likely involved in various pharmacological effects of medicinal plants. This review aimed to evaluate the modulatory effects of medicinal plants and their active constituents on K⁺ channels under pathological conditions. This systematic review was prepared according to the Preferred Reporting Items for the Systematic Reviews and Meta-analyses (PRISMA) 2020 guideline. Four databases, including PubMed, Web of Science, embase, and Scopus, were searched. We identified 687 studies from these databases, from which we selected 13 in vivo studies for the review by using the Population, Intervention, Comparison, Outcomes, Study (PICOS) tool. The results of the 13 selected studies showed a modulatory effect of medicinal plants or their active constituents on ATP-sensitive potassium channels (K_ATP), and small (SK_Ca) and large (BK_Ca) conductance calcium-activated K⁺ channels in several pathological conditions such as nociception, brain ischemia, seizure, diabetes, gastric ulcer, myocardial ischemia-reperfusion, and hypertension via possible involvement of the nitric oxide/cyclic GMP pathway and protein kinase. K⁺ channels should be considered as significant therapeutic milestones in the treatment of several diseases. We believe that understanding the mechanism behind the interaction of medicinal plants with K⁺ channels can facilitate drug development for the treatment of various K⁺ channel-related disorders.

Activated Protein C Strengthens Cardiac Tolerance to Ischemic Insults in Aging

BACKGROUND

APC (activated protein C) is a plasma serine protease with anticoagulant and anti-inflammatory activities. EPCR (Endothelial protein C receptor) is associated with APC's activity and mediates its downstream signaling events. APC exerts cardioprotective effects during ischemia and reperfusion (I/R). This study aims to characterize the role of the APC-EPCR axis in ischemic insults in aging.

METHODS

Young (3-4 months) and aged (24-26 months) wild-type C57BL/6J mice, as well as EPCR point mutation (EPCR^R84A/R84A) knockin C57BL/6J mice incapable of interaction with APC and its wild type of littermate C57BL/6J mice, were subjected to I/R. Wild-type APC, signaling-selective APC-2Cys, or anticoagulant-selective APC-E170A were administrated before reperfusion.

RESULTS

The results demonstrated that cardiac I/R reduces APC activity, and the APC activity was impaired in the aged versus young hearts possibly attributable to the declined EPCR level with aging. Serum EPCR measurement showed that I/R triggered the shedding of membrane EPCR into circulation, while administration of APC attenuated the I/R-induced EPCR shedding in both young and aged hearts. Subsequent echocardiography showed that APC and APC-2Cys but not APC-E170A ameliorated cardiac dysfunction during I/R in both young and aged mice. Importantly, APC elevated the resistance of the aged heart to ischemic insults through stabilizing EPCR. However, all these cardioprotective effects of APC were blunted in the EPCR^R84A/R84A mice versus its wild-type littermates. The ex vivo working heart and metabolomics results demonstrated that AMPK (AMP-activated protein kinase) mediates acute adaptive response while AKT (protein kinase B) is involved in chronic metabolic programming in the hearts with APC treatment.

CONCLUSIONS

I/R stress causes shedding of the membrane EPCR in the heart, and administration of APC prevents I/R-induced cardiac EPCR shedding that is critical for limiting cardiac damage in aging.

Temporal Trend of Mortality Due to Ischemic Heart Diseases in Northeastern Brazil (1996-2016): An Analysis According to Gender and Age Group

BACKGROUND

Ischemic heart disease (IHD) is the leading cause of death among cardiovascular diseases (CVD).

OBJECTIVE

To describe the sociodemographic profile and analyze the trend in the mortality rate due to IHD, according to sex and by age group, in the states of the Northeast region of Brazil, from 1996 to 2016.

METHODS

Ecological study involving IHD mortality in the northeastern states. Variables analyzed: sex, age, education, marital status, ICD-10 category and state of residence. Crude and standardized rates were calculated. Death data were collected from the Mortality Information System (SIM) and population data from the Brazilian Institute of Geography and Statistics (IBGE). In temporal analyzes the regression model by inflection points was used, with the calculation of annual percent change (APC) and average annual percent change of the period (AAPC). A 95% confidence interval and a significance level of 5% were considered.

RESULTS

405916 deaths due to IHD were registered in the northeast region during the study period. The death profile is characterized by men (n=229006; 56,42%), elderly (n=301379; 74,25%), race/color brown (n=197936; 48,76%), elementary or <4 years at school (n=232599; 57,30%) and married (n=179599; 44,25%). There was an unusual highlight to the increase in the annual growth rate in the age group of adolescents (AAPC: 5,2%, p <0.01). The standardized regional mortality rate grew from 30,7 per 100,000 inhabitants in 1996 to 53.8 per 100,000 in 2016 (AAPC 2.8%; p<0.01). All nine states presented a statistically significant growth trend, with emphasis on Maranhão (AAPC 7,6%; p<0.01) and Piauí (AAPC 6,0%; p<0.01).

CONCLUSION

The prevalent observed profile was male, elderly, race/color brown, low education level and married. Mortality due to IHD presented an upward trend in all states, although with an uneven pattern among the federated units.

A New Therapeutic Candidate for Cardiovascular Diseases: Berberine

Cardiovascular diseases (CVD) are the leading cause of death in the world. However, due to the limited effectiveness and potential adverse effects of current treatments, the long-term prognosis of CVD patients is still discouraging. In recent years, several studies have found that berberine (BBR) has broad application prospects in the prevention and treatment of CVD. Due to its effectiveness and safety for gastroenteritis and diarrhea caused by bacterial infections, BBR has been widely used in China and other Asian countries since the middle of the last century. The development of pharmacology also provides evidence for the multi-targets of BBR in treating CVD. Researches on CVD, such as arrhythmia, atherosclerosis, dyslipidemia, hypertension, ischemic heart disease, myocarditis and cardiomyopathy, heart failure, etc., revealed the cardiovascular protective mechanisms of BBR. This review systematically summarizes the pharmacological research progress of BBR in the treatment of CVD in recent years, confirming that BBR is a promising therapeutic option for CVD.

DJ-1: A promising therapeutic candidate for ischemia-reperfusion injury

DJ-1 is a multifaceted protein with pleiotropic functions that has been implicated in multiple diseases, ranging from neurodegeneration to cancer and ischemia-reperfusion injury. Ischemia is a complex pathological state arising when tissues and organs do not receive adequate levels of oxygen and nutrients. When the blood flow is restored, significant damage occurs over and above that of ischemia alone and is termed ischemia-reperfusion injury. Despite great efforts in the scientific community to ameliorate this pathology, its complex nature has rendered it challenging to obtain satisfactory treatments that translate to the clinic. In this review, we will describe the recent findings on the participation of the protein DJ-1 in the pathophysiology of ischemia-reperfusion injury, firstly introducing the features and functions of DJ-1 and, successively highlighting the therapeutic potential of the protein.

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DJ-1 has been shown to confer protection in ischemia-reperfusion injury models.

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DJ-1 protection relies on the activation of antioxidant signaling pathways.

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DJ-1 regulates mitochondrial homeostasis during ischemia and reperfusion.

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DJ-1 seems to modulate ion homeostasis during ischemia and reperfusion.

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DJ-1 may represent a promising therapeutic target for ischemia-reperfusion injury.

The Cardioprotective PKA-Mediated Hsp20 Phosphorylation Modulates Protein Associations Regulating Cytoskeletal Dynamics

The cytoskeleton has a primary role in cardiomyocyte function, including the response to mechanical stimuli and injury. The small heat shock protein 20 (Hsp20) conveys protective effects in cardiac muscle that are linked to serine-16 (Ser16) Hsp20 phosphorylation by stress-induced PKA, but the link between Hsp20 and the cytoskeleton remains poorly understood. Herein, we demonstrate a physical and functional interaction of Hsp20 with the cytoskeletal protein 14-3-3. We show that, upon phosphorylation at Ser16, Hsp20 translocates from the cytosol to the cytoskeleton where it binds to 14-3-3. This leads to dissociation of 14-3-3 from the F-actin depolymerization regulator cofilin-2 (CFL2) and enhanced F-actin depolymerization. Importantly, we demonstrate that the P20L Hsp20 mutation associated with dilated cardiomyopathy exhibits reduced physical interaction with 14-3-3 due to diminished Ser16 phosphorylation, with subsequent failure to translocate to the cytoskeleton and inability to disassemble the 14-3-3/CFL2 complex. The topological sequestration of Hsp20 P20L ultimately results in impaired regulation of F-actin dynamics, an effect implicated in loss of cytoskeletal integrity and amelioration of the cardioprotective functions of Hsp20. These findings underscore the significance of Hsp20 phosphorylation in the regulation of actin cytoskeleton dynamics, with important implications in cardiac muscle physiology and pathophysiology.

Multifunctional Conductive Biomaterials as Promising Platforms for Cardiac Tissue Engineering

Adult cardiomyocytes are terminally differentiated cells that result in minimal intrinsic potential for the heart to self-regenerate. The introduction of novel approaches in cardiac tissue engineering aims to repair damages from cardiovascular diseases. Recently, conductive biomaterials such as carbon- and gold-based nanomaterials, conductive polymers, and ceramics that have outstanding electrical conductivity, acceptable mechanical properties, and promoted cell-cell signaling transduction have attracted attention for use in cardiac tissue engineering. Nevertheless, comprehensive classification of conductive biomaterials from the perspective of cardiac cell function is a subject for discussion. In the present review, we classify and summarize the unique properties of conductive biomaterials considered beneficial for cardiac tissue engineering. We attempt to cover recent advances in conductive biomaterials with a particular focus on their effects on cardiac cell functions and proposed mechanisms of action. Finally, current problems, limitations, challenges, and suggested solutions for applications of these biomaterials are presented.

Protective effect of Shengmai injection on myocardial endothelial cell glycoprotein detachment after myocardial ischemia-reperfusion injury in isolated rat hearts

OBJECTIVE

To investigate effects of Shengmai injection (SMI) postconditioning on myocardial ischemia-reperfusion injury (MIRI) in isolated rat hearts.

MATERIALS AND METHODS

A total of thirty isolated hearts were randomly divided into three groups: Sham group, I/R group and SMI group. Sham group was continuously perfused with K-H solution for 120 minutes. I/R group and SMI group were given balanced perfusion for 30 min followed by reperfusion for 60 min, with an interval of 30 min, and those in the SMI group were given postconditioning with 1% SMI during the first 10 min of reperfusion. The left ventricular function, markers of myocardial injury, endothelial cell injury and oxidative stress injury were measured at 30 minutes after equilibration (t0), 30 minutes after ischemia (t2) and 60 minutes after reperfusion (t3).

RESULTS

The results showed that there was no significant difference for all observation indexes at t0. Compared with the Sham group, real portfolio project and coronary arterial flow rate and the activity of superoxide dismutase were significantly decreased in the I/R group, whereas those in the SMI group were significantly higher. Left ventricular end-diastolic pressure, the concentrate of malondialdehyde, lactate dehydrogenase, cTn-I, hyaluronic acid, heparin sulphate, syndecan-1 in the I/R group were markedly higher than those in the Sham group, whereas those in the SMI group were significantly lower.

CONCLUSION

In summary, the present study indicated that 1% SMI postconditioning can alleviate the detachment of endothelial cell glycoprotein envelope induced by myocardial ischemia-reperfusion injury, and its mechanism is probably related to the inhibition of the oxidative stress injury.

Coptisine alleviates ischemia/reperfusion-induced myocardial damage by regulating apoptosis-related proteins

Coptisine is an alkaloid with many biological functions, but studies on its mechanism in myocardial ischemia-reperfusion (I/R) injury are less reported. Hypoxia-reoxygenation (H/R) -treated cardiomyocytes injury and I/R-induced myocardial tissues damage were created in rat models with or without the pre-treatment of coptisine. The proliferation and apoptosis of cardiomyocytes and changes of myocardial tissues were observed after the pre-treatment of coptisine. The pre-treatment of coptisine promoted cell proliferation and inhibited apoptosis of H/R-injured cardiomyocytes, and alleviated the myocardial tissue injury caused by I/R in rats. Moreover, coptisine promoted the expressions of anti-apoptotic proteins and inhibited the expressions of pro-apoptotic proteins in vivo and in vitro. The current study found that coptisine had protective effects on I/R-induced myocardial damage, which may provide a new insight into the treatment of I/R.

Comprehensive analysis of the cardiac proteome in a rat model of myocardial ischemia-reperfusion using a TMT-based quantitative proteomic strategy

Background

Traditional studies of the cardiac proteome have mainly investigated in an animal model by two-dimensional gel electrophoresis (2-DE). However, the results have not been of satisfactory quality for an understanding of the underlying mechanism. Recent quantitative proteomic methods have been improved to overcome these limitations. To comprehensively study the cardiac proteome in a rat model of ischemia-reperfusion (IR), we developed a tandem mass tag (TMT)-based quantitative proteomic strategy. Furthermore, using this strategy, we examined the molecular mechanisms underlying the prevention of myocardial infarction by the intake of Triticum aestivum L. extract (TALE), a representative dietary fiber grain.

Methods

Cardiac proteomes were analyzed by 2-DE as a gel-based approach, and TMT labeling coupled with two-dimensional liquid chromatography (2D-LC) and tandem mass spectrometry (MS/MS) as a non-gel-based quantitative approach. Additionally, gene ontology annotation was conducted by PANTHER database. Several proteins of interest were verified by a Western blot analysis.

Results

Total 641 proteins were identified commonly from two independent MS datasets using 2D-LC MS/MS. Among these, we identified 151 IR-related proteins that were differentially expressed between the sham-operation group and IR group, comprising 62 up-regulated proteins and 89 down-regulated proteins. Most of the reduced proteins were involved in metabolic processes. In addition, 57 of the IR-related proteins were affected by TALE intake, representing 25 up-regulated proteins and 32 down-regulated proteins. In particular, TALE intake leads to a switch in metabolism to reduce the loss of high-energy phosphates and the accumulation of harmful catabolites (especially reactive oxygen species (ROS)) and to maintain cytoskeleton balance, leading to a reduction in cardiac IR injury.

Conclusions

Our study provides a comprehensive proteome map of IR-related proteins and potential target proteins and identifies mechanisms implicated in the prevention of myocardial infarction by TALE intake in a rat IR model.

Roles and Mechanisms of Hawthorn and Its Extracts on Atherosclerosis: A Review

Cardiovascular disease (CVD), especially atherosclerosis, is a leading cause of morbidity and mortality globally; it causes a considerable burden on families and caregivers and results in significant financial costs being incurred. Hawthorn has an extensive history of medical use in many countries. In China, the use of hawthorn for the treatment of CVD dates to 659 AD. In addition, according to the theory of traditional Chinese medicine, it acts on tonifying the spleen to promote digestion and activate blood circulation to dissipate blood stasis. This review revealed that the hawthorn extracts possess serum lipid-lowering, anti-oxidative, and cardiovascular protective properties, thus gaining popularity, especially for its anti-atherosclerotic effects. We summarize the four principal mechanisms, including blood lipid-lowering, anti-oxidative, anti-inflammatory, and vascular endothelial protection, thus providing a theoretical basis for further utilization of hawthorn.

Urolithin B, a gut microbiota metabolite, protects against myocardial ischemia/reperfusion injury via p62/Keap1/Nrf2 signaling pathway

Ischemia/reperfusion (IR) induces additional damage during the restoration of blood flow to ischemic myocardium. Urolithin B (UB) is one of the gut metabolites of ellagitannins, a class of antioxidant polyphenols, which was found to be protective against oxidative stress in multiple organs. However, the role of UB in cardiovascular disease remains elusive. Adult Sprague Dawley rats were subjected to left anterior descending artery ligation for 30 min followed by 120 min of reperfusion, with or without UB treatment. In vitro, the H9c2 cardiomyocytes were subjected to hypoxia (94 %N₂/5 %CO₂/1 %O₂) for 3 h, followed by reoxygenation (74 %N₂/5 %CO₂/21 %O₂) for 3 h (HR). UB was found to decrease myocardial infarct size and attenuate the cardiac dysfunction in the rats after IR, and protect against HR injury in H9c2 cardiomyocytes. Mechanistically, UB inhibited autophagy by activating Akt/mTOR/ULK1 pathway and protected against oxidative stress and caspase 3-dependent cell apoptosis. In particular, UB induced accumulation of p62 and its interaction with Keap1, which promoted Nrf2 nuclear translocation during HR insult. Of note, the protection of UB against superoxide production and apoptotic cell death was compromised with Nrf2 gene silencing. Taken together, our findings suggested that UB protected against myocardial IR injury at least partially via the p62/Keap1/Nrf2 signaling pathway, which highlights the potential of UB as a novel therapy for ischemic heart disease.

Crosstalk between Mitochondria and Cytoskeleton in Cardiac Cells

Elucidation of the mitochondrial regulatory mechanisms for the understanding of muscle bioenergetics and the role of mitochondria is a fundamental problem in cellular physiology and pathophysiology. The cytoskeleton (microtubules, intermediate filaments, microfilaments) plays a central role in the maintenance of mitochondrial shape, location, and motility. In addition, numerous interactions between cytoskeletal proteins and mitochondria can actively participate in the regulation of mitochondrial respiration and oxidative phosphorylation. In cardiac and skeletal muscles, mitochondrial positions are tightly fixed, providing their regular arrangement and numerous interactions with other cellular structures such as sarcoplasmic reticulum and cytoskeleton. This can involve association of cytoskeletal proteins with voltage-dependent anion channel (VDAC), thereby, governing the permeability of the outer mitochondrial membrane (OMM) to metabolites, and regulating cell energy metabolism. Cardiomyocytes and myocardial fibers demonstrate regular arrangement of tubulin beta-II isoform entirely co-localized with mitochondria, in contrast to other isoforms of tubulin. This observation suggests the participation of tubulin beta-II in the regulation of OMM permeability through interaction with VDAC. The OMM permeability is also regulated by the specific isoform of cytolinker protein plectin. This review summarizes and discusses previous studies on the role of cytoskeletal proteins in the regulation of energy metabolism and mitochondrial function, adenosine triphosphate (ATP) production, and energy transfer.

NCX and EAAT transporters in ischemia: At the crossroad between glutamate metabolism and cell survival

Energy metabolism impairment is a central event in the pathophysiology of ischemia. The limited availability of glucose and oxygen strongly affects mitochondrial activity, thus leading to ATP depletion. In this setting, the switch to alternative energy sources could ameliorate cells survival by enhancing ATP production, thus representing an attractive strategy for ischemic treatment. In this regard, some studies have recently re-evaluated the metabolic role of glutamate and its potential to promote cell survival under pathological conditions. In the present review, we discuss the ability of glutamate to exert an "energizing role" in cardiac and neuronal models of hypoxia/reoxygenation (H/R) injury, focusing on the Na⁺/Ca²⁺ exchanger (NCX) and the Na⁺-dependent excitatory amino acid transporters (EAATs) as key players in this metabolic pathway.

MicroRNA-20b-5p regulates propofol-preconditioning-induced inhibition of autophagy in hypoxia-and-reoxygenation-stimulated endothelial cells

Ischemia-reperfusion (IR) injury is a major cause of clinical emergencies during and after surgical procedures. Propofol protects the heart from cardiovascular IR injury by inhibiting autophagy. MicroRNAs (miRNAs) participate in anesthetic-regulated cardiovascular injury. MiR-20b-5p targets unc-51-like autophagy activating kinase 1 (ULK1). Its role in propofol-modulated cardiovascular IR injury remains unclear, however. In this study, we used an in vitro model of hypoxia-reoxygenation (HR)-induced injury to human umbilical vein endothelial cells (HUVECs) to determine the protective effect of miR-20b-5p in cells preconditioned with propofol. We found that miR-20b-5p was significantly higher and ULK1 was lower in propofol-preconditioned HUVECs with HR injury than in HUVECs with HR injury only. Additionally, miR-20b-5p overexpression increased cell viability and repressed autophagy and apoptosis more in propofol-preconditioned HUVECs with HR injury than in HUVECs with HR injury only. A luciferase reporter assay confirmed the target reaction between miR-20b-5p and ULK1. Overexpression of ULK1 restrained the protective effect of miR-20b-5p in propofol-preconditioned HUVECs with HR injury. In conclusion, our results indicate that propofol inhibits autophagic cell death via the miR-20b-5p-ULKI axis and that ULK1 may be a therapeutic target for cardiovascular IR injury.

Effect of sulphoraphane on newborn mouse cardiomyocytes undergoing ischaemia/reperfusion injury

Context: Sulphoraphane (SFN) is an isothiocyanate, having antioxidant activity, antitumor, and therapeutic effects on cardiovascular disease.Objective: This study explores the mechanisms of SFN preconditioning on ischaemia/reperfusion injury (IRI).Materials and methods: Cardiomyocytes were divided into four groups as follows: control group (normoxic condition), SFN group (5 μmol/L), hypoxia/reoxygenation (H/R) group (1 h, 3 h) and SFN + H/R group. Cell viability was determined by MTT method. Levels of creatine kinase (CK), nitric oxide (NO), superoxide dismutase (SOD) and maleic dialdehyde (MDA) were determined by colorimetric method. Cell apoptosis, levels of reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) were determined by flow cytometry. Levels of Bax, Bcl-2, C caspase-3, NF-E2-related factor 2 (Nrf2) and haem oxygenase-1 (HO-1) were detected by Western blot.Results: H/R model inhibited cell viability, increased the levels of LDH, CK, Bax and C caspase-3, and decreased the levels of NO, Bcl-2, while the effect of H/R was partially reversed by SFN. SFN treatment reduced ROS, MDA (from 4.9 nM to 2.8 nM) production, elevated SOD level (from 39.5 U/mL to 61.7 U/mL) and improved MMP damage. Under the effect of SFN, up-regulation of nuclear Nrf2 expression and down-regulation of cytosolic Nrf2 expression were observed, which led to Nrf2 nuclear translocation and enhanced the expression of HO-1.Conclusion: These results suggested that SFN had a protective effect on cardiomyocytes undergoing IRI, and its mechanism may be realized via activating the Nrf2/HO-1 pathway, thereby inhibiting apoptosis. This might provide a new approach for the treatment of ischaemic heart disease.

Expansion of Human Pluripotent Stem Cell-derived Early Cardiovascular Progenitor Cells by a Cocktail of Signaling Factors

Cardiovascular progenitor cells (CPCs) derived from human pluripotent stem cells (hPSCs) are proposed to be invaluable cell sources for experimental and clinical studies. This wide range of applications necessitates large-scale production of CPCs in an in vitro culture system, which enables both expansion and maintenance of these cells. In this study, we aimed to develop a defined and efficient culture medium that uses signaling factors for large-scale expansion of early CPCs, called cardiogenic mesodermal cells (CMCs), which were derived from hPSCs. Chemical screening resulted in a medium that contained a reproducible combination of three factors (A83-01, bFGF, and CHIR99021) that generated 1014 CMCs after 10 passages without the propensity for tumorigenicity. Expanded CMCs retained their gene expression pattern, chromosomal stability, and differentiation tendency through several passages and showed both the safety and possible cardio-protective potentials when transplanted into the infarcted rat myocardium. These CMCs were efficiently cryopreserved for an extended period of time. This culture medium could be used for both adherent and suspension culture conditions, for which the latter is required for large-scale CMC production. Taken together, hPSC-derived CMCs exhibited self-renewal capacity in our simple, reproducible, and defined medium. These cells might ultimately be potential, promising cell sources for cardiovascular studies.

BPA disrupts the cardioprotection by 17β-oestradiol against ischemia/reperfusion injury in isolated guinea pig hearts

Bisphenol A (BPA) is an environmental oestrogen or xenoestrogen (XEs). XEs represent a health risk due to their potential for endocrine disruption and ability to mimic estrogenic activity. The effects of BPA on isolated hearts under normal and ischemia/reperfusion (I/R) conditions were investigated for the first time, with a focus on the effects of BPA and 17β-oestradiol (E₂) co-administration on I/R injury. Our results indicated that BPA at 10^-7 M and 10^-5 M did not significantly affect heart rate (HR), coronary flow (CF), lactate dehydrogenase (LDH) or creatine kinase (CK) release in normal or I/R isolated hearts within the 90 min. However, E₂ exerted a protective effect against I/R injury, whereas, BPA inhibited the cardio-protective effects of E₂ on HR, CF, and LDH and CK release. Furthermore, BPA in combination with E₂ aggravated I/R injury by increasing infarct size and causing a more severe ultrastructural disruption as compared to treatment with E₂ alone. Based on our results, we conclude that BPA inhibits the cardio-protective effects of E₂ on I/R-injured hearts, despite not significantly affecting normal or I/R isolated hearts.

Cyclic helix B peptide ameliorates acute myocardial infarction in mice by inhibiting apoptosis and inflammatory responses

Cyclic helix B peptide (CHBP) is a peptide derivant of erythropoietin with powerful tissue-protective efficacies in a variety of organ injuries, but without erythropoietic effect. However, the role of CHBP in acute myocardial infarction (AMI) and related mechanisms are not studied yet. In this study, we found in a murine AMI model that the administration of CHBP could ameliorate cardiac injury, increase the survival rate, inhibit cardiomyocyte apoptosis, improve cardiac function and remodeling, and reduce the expression of inflammatory cytokines in the serum and kidney tissue both at 24 h and 8 weeks following AMI. This study suggests that CHBP has the potential to be used as an effective drug in the treatment of AMI.

Effects of a new compound containing Palmitoylethanolamide and Baicalein in myocardial ischaemia/reperfusion injury in vivo

BACKGROUND

Myocardial ischemia/reperfusion (I/R) injury is the principal cause of death, happens after prolonged obstruction of the coronary arteries.  The first intervention to limit myocardial damage is directed to restoration of perfusion, to avoid inflammatory response and a significant oxidative stress triggered by infarction. Palmitoylethanolamide (PEA), is a well-known fatty acid amide-signaling molecule that possess an important anti-inflammatory and analgesic effects. PEA does not hold the ability to inhibit free radicals formation. Baicalein, a bioactive component isolated from a Chinese herbal medicine, has multiple pharmacological activities, such as a strong anti-oxidative effects.

PURPOSE

A combination of PEA and Baicalein could have beneficial effects on oxidative stress produced by inflammatory response.

STUDY DESIGN

In the present study we explored the effects of composite containing PEA and Baicalein in a model of myocardial I/R injury.

METHODS

Myocardial ischemia/reperfusion injury was induced by occlusion of the left anterior descending coronary artery for 30 min followed by 2 h of reperfusion. PEA-Baicalein (9:1), was administered (10 mg/kg) 5 min before the end of ischemia and 1 h after reperfusion.

RESULTS

In this study, we clearly demonstrated that PEA-Baicalein treatment decreases myocardial tissue injury, neutrophils infiltration, markers for mast cell activation expression as chymase and tryptase and pro-inflammatory cytokines production (TNF-α, IL-1β). Moreover, PEA-Baicalein treatment reduces stress oxidative and modulates Nf-kB and apoptosis pathways.

CONCLUSION

These results support the idea that the association between PEA and Baicalein should be a potent candidate for the treatment of myocardial I/R injury.

Tournefolic acid B, derived from Clinopodium chinense (Benth.) Kuntze, protects against myocardial ischemia/reperfusion injury by inhibiting endoplasmic reticulum stress-regulated apoptosis via PI3K/AKT pathways

BACKGROUND

Protection the heart from ischemia/reperfusion (I/R) injury is an area of intense research, as myocardial infarction is a major cause of mortality and morbidity all around the world. Tournefolic acid B (TAB) is a relative new compound derived from Clinopodium chinense (Benth.) Kuntze (Chinese name: Feng Lun Cai). This traditional Chinese herbal medicine has been used for its activities on anti-inflammatory, lowering blood glucose, antitumor and antiradiation. However, the pharmacological effects of TAB were rarely studied.

PURPOSE

Pathways involving phosphoinositide 3-kinase (PI3K) and protein kinase b (Akt) are crucial in regulating the ER stress and associated apoptosis in the process of I/R injury. In the present study, we aim to investigate the cardioprotective effects of tournefolic acid B (TAB) against myocardial I/R injury and explore the molecular mechanisms involved.

STUDY DESIGN

H9c2 cadiomyocyte were incubated with TAB for 24 h and then exposed to hypoxia/reoxygenation. Isolated rat hearts were subjected to global ischemia and reperfusion in the absence or presence of TAB.

METHODS

The possible mechanisms were investigated in vitro and ex vivo by multiple detection methods including JC-1 staining, ROS detection, activities of caspases detection, TUNEL staining, and Western-blot analysis.

RESULTS

We found that TAB significantly improved the hemodynamic parameters (LVeDP, LVSP, + dP/dt_max, - dP/dt_min, and HR) of isolated rat hearts, and depressed the cardiomyocyte apoptosis. Besides, TAB inhibited the oxidative stress by adjusting the activities of antioxidant enzymes (SOD, CAT, and GSH-Px). The I/R injury triggered the endoplasmic reticulum (ER) stress by activating the ER proteins, such as Grp78, ATF6, PERK, and eIf2α. which are all refrained by TAB. TAB also enhanced the phosphorylation of PI3K and AKT, inhibited the expression of CHOP and Caspase-12, reduced the phosphorylation of JNK, and increased Bcl-2/Bax ratio.

CONCLUSION

TAB protects against myocardial I/R injury by suppressing PI3K/AKT-mediated ER stress, oxidative stress, and apoptosis, revealing a promising therapeutic agent against ischemic cardiovascular diseases.

Changing Metabolism in Differentiating Cardiac Progenitor Cells-Can Stem Cells Become Metabolically Flexible Cardiomyocytes?

The heart is a metabolic omnivore and the adult heart selects the substrate best suited for each circumstance, with fatty acid oxidation preferred in order to fulfill the high energy demand of the contracting myocardium. The fetal heart exists in an hypoxic environment and obtains the bulk of its energy via glycolysis. After birth, the "fetal switch" to oxidative metabolism of glucose and fatty acids has been linked to the loss of the regenerative phenotype. Various stem cell types have been used in differentiation studies, but most are cultured in high glucose media. This does not change in the majority of cardiac differentiation protocols. Despite the fact that metabolic state affects marker expression and cellular function and activity, the substrate composition is currently being overlooked. In this review we discuss changes in cardiac metabolism during development, the various protocols used to differentiate progenitor cells to cardiomyocytes, what is known about stem cell metabolism and how consideration of metabolism can contribute toward maturation of stem cell-derived cardiomyocytes.

Gastrin Protects Against Myocardial Ischemia/Reperfusion Injury via Activation of RISK (Reperfusion Injury Salvage Kinase) and SAFE (Survivor Activating Factor Enhancement) Pathways

BACKGROUND

Ischemia/reperfusion injury (IRI) is one of the most predominant complications of ischemic heart disease. Gastrin has emerged as a regulator of cardiovascular function, playing a key protective role in hypoxia. Serum gastrin levels are increased in patients with myocardial infarction, but the pathophysiogical significance of this finding is unknown. The purpose of this study was to determine whether and how gastrin protects cardiac myocytes from IRI.

METHODS AND RESULTS

Adult male Sprague-Dawley rats were used in the experiments. The hearts in living rats or isolated Langendorff-perfused rat hearts were subjected to ischemia followed by reperfusion to induce myocardial IRI. Gastrin, alone or with an antagonist, was administered before the induction of myocardial IRI. We found that gastrin improved myocardial function and reduced the expression of myocardial injury markers, infarct size, and cardiomyocyte apoptosis induced by IRI. Gastrin increased the phosphorylation levels of ERK1/2 (extracellular signal-regulated kinase 1/2), AKT (protein kinase B), and STAT3 (signal transducer and activator of transcription 3), indicating its ability to activate the RISK (reperfusion injury salvage kinase) and SAFE (survivor activating factor enhancement) pathways. The presence of inhibitors of ERK1/2, AKT, or STAT3 abrogated the gastrin-mediated protection. The protective effect of gastrin was via CCK2R (cholecystokinin 2 receptor) because the CCK2R blocker CI988 prevented the gastrin-mediated protection of the heart with IRI. Moreover, we found a negative correlation between serum levels of cardiac troponin I and gastrin in patients with unstable angina pectoris undergoing percutaneous coronary intervention, suggesting a protective effect of gastrin in human cardiomyocytes.

CONCLUSIONS

These results indicate that gastrin can reduce myocardial IRI by activation of the RISK and SAFE pathways.

MiR-34a-5p mediates sevoflurane preconditioning induced inhibition of hypoxia/reoxygenation injury through STX1A in cardiomyocytes

Anesthetic preconditioning is a cellular protective approach whereby exposure to a volatile anesthetic renders cardio injury. Sevoflurane preconditioning has been shown to exhibit cardio protective effect on hypoxia/reoxygenation (H/R) injury, but the underlying mechanism is unclear. Syntaxin 1A (STX1A), an important regulator in cardio disease, was predicted to be the target gene of microRNA-34a-5p (miR-34a-5p). The current research was designed to delineate the role of miR-34a-5p in regulating sevoflurane preconditioning in cardiomyocytes injury. In this study, the results demonstrated that the expression of STX1A was significantly increased, while miR-34a-5p was dramatically decreased in sev-preconditioning H9c2 cells as compared with cells only under H/R stimulation. Moreover, miR-34a-5p regulated the protective effect of sev-preconditioning in injured H9c2 cells by mediating cell proliferation and cell apoptosis. Additionally, the luciferase report confirmed the targeting reaction between STX1A and miR-34a-5p. Taken together, our study suggested that miR-34a-5p regulated sev-preconditioning induced inhibition of hypoxia/reoxygenation injury through mediating STX1A, provided a potential therapeutic target for anesthetic protection in cardio disease.

Opioids in Cardiovascular Disease: Therapeutic Options

The World Health Organization suggests that the cardiovascular diseases (CVDs) are the major cause of mortality and account for two-thirds of the deaths all over the world. These diseases kill about 17 million people every year and 3 in every 10 deaths are due to these diseases. The past decade has seen considerable improvements in diagnosis as well as treatment of various heart diseases. Various new therapeutic targets are being identified through in-depth knowledge of the disease mechanisms which has favored the testing of new strategies leading to newer treatment options. Opioid peptides and G-protein-coupled opioid receptors (ORs) have been previously studied widely in terms of central nervous system actions in mitigating the pain and drug abuse. The OR agonism or antagonism induces cytoprotective states in the myocardium, rendering these receptors as an attractive target for protection of heart from the fatal heart diseases. The opioids can provide an extended window of protection of the heart from various diseases. Although the mechanisms may not be fully understood, they seem to play a crucial role in various CVDs such as hypertension, hyperlipidemia, ischemic heart disease myocardial ischemia, and congestive heart failure. Since these compounds are already being used in acute and chronic pain, soon these compounds might be approved for use as cardioprotective agents. The following review focuses on the new information acquired on the role of the ORs in various CVDs.

Cardioprotection and thyroid hormones

The evolution of cardiac disease after an acute ischemic event depends on a complex and dynamic network of mechanisms alternating from ischemic damage due to acute coronary occlusion to reperfusion injury due to the adverse effects of coronary revascularization till post-ischemic remodeling. Cardioprotection is a new purpose of the therapeutic interventions in cardiology with the goal to reduce infarct size and thus prevent the progression toward heart failure after an acute ischemic event. In a complex biological system such as the human one, an effective cardioprotective strategy should diachronically target the network of cross-talking pathways underlying the disease progression. Thyroid system is strictly interconnected with heart homeostasis, and recent studies highlighted its role in cardioprotection, in particular through the preservation of mitochondrial function and morphology, the antifibrotic and proangiogenetic effect and also to the potential induction of cell regeneration and growth. The objective of this review was to highlight the cardioprotective role of triiodothyronine in the complexity of post-ischemic disease evolution.

The cardioprotective effects of (-)-Epicatechin are mediated through arginase activity inhibition in a murine model of ischemia/reperfusion

The production of nitric oxide (NO) by nitric oxide synthases (NOS) depends on the bioavailability of L-arginine as NOS competes with arginase for this common substrate. As arginase activity increases, less NO is produced and adverse cardiovascular consequences can emerge. (-)-Epicatechin (EPI), the most abundant flavonoid in cacao, has been reported to stimulate endothelial and neuronal NOS expression and function leading to enhanced vascular function and cardioprotective effects. However, little is known about the effects of EPI on myocardial arginase activity. The aim of the present study was to determine if EPI is able to interact and modulate myocardial arginase and NOS expression and activity. For this purpose, in silico modeling, in vitro activity assays and a rat model of ischemia/reperfusion injury were used. In silico and in vitro results demonstrate that EPI can interact with arginase and significantly decrease its activity. In vivo, 10 days of EPI pretreatment reduces ischemic myocardium arginase expression while increasing NOS expression and phosphorylation levels. Altogether, these results may partially account for the cardioprotective effects of EPI.

Elevated circulating miR-126-3p expression in patients with acute myocardial infarction: its diagnostic value

Acute myocardial infarction (AMI) therapy has not remarkably improved due to delay in the diagnosis to a great extent. Circulating microRNAs have shown some potential for diagnosis of cardiovascular diseases. The aim of this study was to estimate the diagnostic value of circulating miR-126-3p for AMI. In our study, circulating miR-126-3p levels were determined by quantitative polymerase chain reaction and the results showed it was 106-fold higher than that in controls, and elevated miR-126-3p was associated with aging through logistic correlation analyses. Receiver-operator characteristic curve was used to evaluate the sensitivity and specificity of miR-126-3p for diagnosis of AMI, indicating that its diagnostic effect was superior to the current clinical markers such as CK, CK-MB, hs-TnI, and MYO. Our results indicate that miR-126-3p in circulation is a potential novel diagnostic biomarker for AMI.

Chronic Intermittent Hypobaric Hypoxia Improves Cardiac Function through Inhibition of Endoplasmic Reticulum Stress

We investigated the role of endoplasmic reticulum stress (ERS) in chronic intermittent hypobaric hypoxia (CIHH)-induced cardiac protection. Adult male Sprague-Dawley rats were exposed to CIHH treatment simulating 5000 m altitude for 28 days, 6 hours per day. The heart was isolated and perfused with Langendorff apparatus and subjected to 30-min ischemia followed by 60-min reperfusion. Cardiac function, infarct size, and lactate dehydrogenase (LDH) activity were assessed. Expression of ERS molecular chaperones (GRP78, CHOP and caspase-12) was assayed by western blot analysis. CIHH treatment improved the recovery of left ventricular function and decreased cardiac infarct size and activity of LDH after I/R compared to control rats. Furthermore, CIHH treatment inhibited over-expression of ERS-related factors including GRP78, CHOP and caspase-12. CIHH-induced cardioprotection and inhibition of ERS were eliminated by application of dithiothreitol, an ERS inducer, and chelerythrine, a protein kinase C (PKC) inhibitor. In conclusion CIHH treatment exerts cardiac protection against I/R injury through inhibition of ERS via PKC signaling pathway.

Mitochondrial Ca2+-activated K+ channels and their role in cell life and death pathways

Ca²⁺-activated K⁺ channels (K_Ca) are expressed at the plasma membrane and in cellular organelles. Expression of all K_Ca channel subtypes (BK, IK and SK) has been detected at the inner mitochondrial membrane of several cell types. Primary functions of these mitochondrial K_Ca channels include the regulation of mitochondrial ROS production, maintenance of the mitochondrial membrane potential and preservation of mitochondrial calcium homeostasis. These channels are therefore thought to contribute to cellular protection against oxidative stress through mitochondrial mechanisms of preconditioning. In this review, we summarize the current knowledge on mitochondrial KCa channels, and their role in mitochondrial function in relation to cell death and survival pathways. More specifically, we systematically discuss studies on the role of these mitochondrial K_Ca channels in pharmacological preconditioning, and according protective effects on ischemic insults to the brain and the heart.

Ischemia/Reperfusion Injury following Acute Myocardial Infarction: A Critical Issue for Clinicians and Forensic Pathologists

Acute myocardial infarction (AMI) is a leading cause of morbidity and mortality. Reperfusion strategies are the current standard therapy for AMI. However, they may result in paradoxical cardiomyocyte dysfunction, known as ischemic reperfusion injury (IRI). Different forms of IRI are recognized, of which only the first two are reversible: reperfusion-induced arrhythmias, myocardial stunning, microvascular obstruction, and lethal myocardial reperfusion injury. Sudden death is the most common pattern for ischemia-induced lethal ventricular arrhythmias during AMI. The exact mechanisms of IRI are not fully known. Molecular, cellular, and tissue alterations such as cell death, inflammation, neurohumoral activation, and oxidative stress are considered to be of paramount importance in IRI. However, comprehension of the exact pathophysiological mechanisms remains a challenge for clinicians. Furthermore, myocardial IRI is a critical issue also for forensic pathologists since sudden death may occur despite timely reperfusion following AMI, that is one of the most frequently litigated areas of cardiology practice. In this paper we explore the literature regarding the pathophysiology of myocardial IRI, focusing on the possible role of the calpain system, oxidative-nitrosative stress, and matrix metalloproteinases and aiming to foster knowledge of IRI pathophysiology also in terms of medicolegal understanding of sudden deaths following AMI.

Mitochondria in Ischemic Heart Disease

A core feature of ischemic heart disease is injury to cardiomyocytes (CMC). Ischemic CMC manifest the molecular mechanisms to undergo the major forms of cell injury and death, namely, oncotic necrosis, necroptosis, apoptosis and unregulated autophagy. Important modulators of ischemic injury are reperfusion and conditioning. Mitochondria have a major role in mediating the injury to CMC through membrane protein complexes referred to as death channels. Apoptosis is mediated by activation of a channel regulated by the Bcl-2 protein family leading to mitochondrial outer membrane permeabilization (MOMP). Oncotic type injury is mediated by opening of the mitochondrial permeability transition pore (mPTP). Mitochondria also have a reperfusion salvage kinase pathway (RISK). With cyclosporine A serving as a prototype, ongoing research is aimed at developing pharmacological approaches to condition and preserve mitochondrial integrity in order to promote CMC survival during episodes of myocardial ischemia.

Antiarrhythmic activity of a new spiro-cyclic benzopyran activator of the cardiac mitochondrial ATP dependent potassium channels

'Compound A' (4(ı)-(N-(4-acetamidobenzyl))-2,2-dimethyl-2,3-dihydro-5(ı)H-spiro[chromene-4,2(ı)-[1,4]oxazinan]-5(ı)-one) is a new spiro-cyclic benzopyran activator of the mitochondrial ATP-dependent potassium channels (mitoKATP). We researched the effect of compound A on ischemia/reperfusion (I/R)-induced ventricular arrhythmias. We also tested the hypothesis that the application of the activation of mitoKATP in combination with the inhibition of sarcolemmal ATP-dependent potassium channels (sarcKATP) may produce a stronger antiarrhythmic effect. In anesthetized rats, myocardial ischemia was performed by ligating the left main coronary artery followed by reperfusion. At a dose of 10 mg/kg, compound A significantly decreased arrhythmia scores and the total length of arrhythmias, whereas this was found to be ineffective at a dose of 3 mg/kg. Pre-treatment with 5-HD, a selective mitoKATP blocker, abolished the antiarrhythmic effect of compound A. Both diazoxide, a selective mitoKATP opener and HMR 1098, a selective sarcKATP blocker, significantly decreased the total length of arrhythmias. However, the combination of neither diazoxide nor compound A with HMR 1098 showed no additional therapeutic benefit. These results reveal that compound A may have a dose-dependent antiarrythmic effect, which is more pronounced than the antiarrhythmic effect of diazoxide. The antiarrhythmic effect of compound A may possibly depend on mitoKATP activation.

Pathobiology of Ischemic Heart Disease: Past, Present and Future

This review provides a perspective on knowledge of ischemic heart disease (IHD) obtained from the contemporary era of research which began in the 1960s and has continued to the present day. Important discoveries have been made by basic and translational scientists and clinicians. Pathologists have contributed significantly to insights obtained from experimental studies and clinicopathological studies in humans. The review also provides a perspective for future directions in research in IHD aimed at increasing basic knowledge and developing additional therapeutic options for patients with IHD.

Baicalin inhibits inflammation and attenuates myocardial ischaemic injury by aryl hydrocarbon receptor

OBJECTIVES

Recent evidence indicates that suppressing inflammation by specific drug target and treatment measures contributes to attenuate ischaemic injury and the related heart diseases. This study aimed to investigate the potential effect of baicalin on myocardial ischaemic injury through inhibition of inflammation by inactivating the aryl hydrocarbon receptor (AhR).

METHODS

The mouse model with myocardial ischaemic injury was prepared by the left anterior descending coronary artery-amputation and then treated using baicalin. After observing the expression of AhR by immunohistochemical staining, the AhR and inflammatory mediators in circulation and myocardial tissues, including high-sensitive C-reactive protein (hsCRP), interleukin (IL)-1β and IL-6, were detected based on enzyme-linked immunosorbent assay, real-time polymerase chain reaction and Western blot methods.

KEY FINDINGS

The results showed that (1) substantial expression of AhR was observed in myocardial tissues; (2) ischaemic injury caused myocardial necrosis and remodelling, and stimulated hsCRP, IL-1β and IL-6 by activation of AhR; and (3) baicalin alleviated the myocardial injury and inflammatory response by inhibiting the expression of AhR.

CONCLUSION

Our findings extend the list of AhR ligands beyond exogenous toxins and endogenous molecules to cardiac immunological factors, and moreover it could be considered potential drug targets due to its pathological modulatory properties, while baicalin demonstrated promise as a novel vehicle for ischaemic heart disease.

Cardioprotection in ischaemia-reperfusion injury: novel mechanisms and clinical translation

In recent decades, robust successes have been achieved in conquering the acutely lethal manifestations of heart disease. Nevertheless, the prevalence of heart disease, especially heart failure, continues to rise. Among the precipitating aetiologies, ischaemic disease is a leading cause of heart failure. In the context of ischaemia, the myocardium is deprived of oxygen and nutrients, which elicits a cascade of events that provokes cell death. This ischaemic insult is typically coupled with reperfusion, either spontaneous or therapeutically imposed, wherein blood supply is restored to the previously ischaemic tissue. While this intervention limits ischaemic injury, it triggers a new cascade of events that is also harmful, viz. reperfusion injury. In recent years, novel insights have emerged regarding mechanisms of ischaemia-reperfusion injury, and some hold promise as targets of therapeutic relevance. Here, we review a select number of these pathways, focusing on recent discoveries and highlighting prospects for therapeutic manipulation for clinical benefit.

The Triggering Receptor Expressed on Myeloid cells-1: A new player during acute myocardial infarction

Following myocardial ischemia, an intense activation of the immune system occurs that leads to inflammatory cytokines and chemokines production and to the recruitment of neutrophils and mononuclear cells in the infarcted area. Although pro-inflammatory signals initiate the cellular events necessary for scar formation, excessive and prolonged inflammation promotes deleterious cardiac remodeling and dysfunction. The triggering receptor expressed on myeloid cells-1 (TREM-1) is a highly conserved immune-receptor expressed by neutrophils and monocytes that acts as an amplifier of the innate immune response. Blockade of TREM-1 activation protects from hyper-responsiveness and death during severe infections. Here we review the role of TREM-1 in orchestrating the inflammatory response that follows MI. TREM-1 deletion (Trem-1-/-) or modulation by the use of a short inhibitory peptide (LR12) dampens myocardial inflammation, limits leukocyte recruitment, and improves heart function and survival in mice or pigs. Moreover, the soluble form of TREM-1 (sTREM-1) is found in the plasma of patients suffering from an acute MI and its concentration is an independent predictor of death. This suggests that TREM-1 may constitute a new therapeutic target during acute MI.

Altered expression of P2Y2 and P2X7 purinergic receptors in the isolated rat heart mediates ischemia-reperfusion injury

The aim of this study is to analyze the expression of purinergic receptors in the heart after ischemia-reperfusion, and their possible role in ischemia-reperfusion injury. Rat hearts were perfused according to the Langendorff technique and subjected to 30 min ischemia followed by 15 min reperfusion. Ischemia-reperfusion reduced the gene expression and protein content of purinergic receptors of the P2Y2 subtype, and increased the gene expression and protein content of the P2X7 subtype. Treatment with the agonist of the P2Y2 subtype 2-thio-UTP and with the antagonist of the P2X7 subtype Brilliant Blue improved myocardial function parameters, reduced cell death and increased the myocardial expression of antiapoptotic markers after ischemia-reperfusion. These results suggest that the myocardial expression of the protective P2Y2 subtype of purinergic receptors is reduced, whereas that of the harmful subtype P2X7 subtype is increased during coronary ischemia-reperfusion. This may contribute to myocardial injury in this condition.

The effect of adenosine deaminase inhibition on the A1 adenosinergic and M2 muscarinergic control of contractility in eu- and hyperthyroid guinea pig atria

The A1 adenosine and M2 muscarinic receptors exert protective (including energy consumption limiting) effects in the heart. We investigated the influence of adenosine deaminase (ADA) inhibition on a representative energy consumption limiting function, the direct negative inotropic effect elicited by the A1 adenosinergic and M2 muscarinergic systems, in eu- and hyperthyroid atria. Furthermore, we compared the change in the interstitial adenosine level caused by ADA inhibition and nucleoside transport blockade, two well-established processes to stimulate the cell surface A1 adenosine receptors, in both thyroid states. A classical isolated organ technique was applied supplemented with the receptorial responsiveness method (RRM), a concentration estimating procedure. Via measuring the contractile force, the direct negative inotropic capacity of N(6)-cyclopentyladenosine, a selective A1 receptor agonist, and methacholine, a muscarinic receptor agonist, was determined on the left atria isolated from 8-day solvent- and thyroxine-treated guinea pigs in the presence and absence of 2'-deoxycoformycin, a selective ADA inhibitor, and NBTI, a selective nucleoside transporter inhibitor. We found that ADA inhibition (but not nucleoside transport blockade) increased the signal amplification of the A1 adenosinergic (but not M2 muscarinergic) system. This action of ADA inhibition developed in both thyroid states, but it was greater in hyperthyroidism. Nevertheless, ADA inhibition produced a smaller rise in the interstitial adenosine concentration than nucleoside transport blockade did in both thyroid states. Our results indicate that ADA inhibition, besides increasing the interstitial adenosine level, intensifies the atrial A1 adenosinergic function in another (thyroid hormone-sensitive) way, suggesting a new mechanism of action of ADA inhibition.