κ-Opioid receptor stimulation inhibits augmentation of Ca2+ transient and hypertrophy induced by isoprenaline in neonatal rat ventricular myocytes — Role of CaMKIIδB

Astragaloside IV attenuates myocardial ischemia/reperfusion injury in rats via inhibition of calcium-sensing receptor-mediated apoptotic signaling pathways

Astragaloside IV (AsIV) is an active saponin extracted from Astragalus membranaceus, which has shown cardioprotective effects in a number of experimental animals. In this study we investigated the molecular mechanisms by which AsIV attenuated the myocardial ischemia reperfusion (MI/R)-induced injury in vitro and in vivo by focusing on calcium-sensing receptor (CaSR) and extracellular signal-regulated kinase 1/2 (ERK1/2). Rat neonatal cardiac myocytes were subjected to a hypoxia/reoxygenation (H/R) procedure in vitro, which significantly decreased the cell viability, increased lactate dehydrogenase (LDH) release, induced cardiomyocyte apoptosis, and increased [Ca²⁺]_i. H/R also increased the expression of CaSR and decreased ERK1/2 phosphorylation levels in H/R-exposed myocytes. Pretreatment with AsIV (60 μmol/L) significantly improved the cell viability and decreased LDH release, attenuated myocyte apoptosis, decreased [Ca²⁺]_i and CaSR expression, and increased the ERK1/2 phosphorylation levels. The protective effects of AsIV against H/R injury were partially inhibited by co-treatment with a CaSR agonist, gadolinium chloride (GdCl₃) or with a specific ERK1/2 inhibitor U0126. For in vivo studies, a rat MI/R model was established. Pre-administration of AsIV (80 mg/kg every day, ig) significantly decreased the myocardium infarct size, creatine kinase-MB (CK-MB) production, serum cardiac troponin (cTnI) levels, and cardiomyocyte apoptosis in the rats with MI/R injury. The therapeutic effects of AsIV were associated with the downregulation of CaSR expression and upregulation of ERK1/2 phosphorylation in myocardial tissues. In summary, astragaloside IV attenuates myocardial I/R injury via inhibition of CaSR/ERK1/2 and the related apoptotic signaling pathways.

The clinical efficacy and safety of the Chinese herbal medicine Astragalus (Huangqi) preparation for the treatment of acute myocardial infarction: A systematic review of randomized controlled trials

BACKGROUND

In recent years, with the enormous advances in the field of cardiac intervention technology, the survival rate of patients with acute myocardial infarction (AMI) has been improved significantly. However, the risk of arrhythmias and heart failure remains very high in AMI patients for long-term prognosis. Chinese herbal medicine (CHM) is more and more used in the treatment of AMI because of its good curative effect and less side effects. The target of this research is to analyze the efficacy and safety of Astragalus (Huangqi) preparation in the treatment of AMI by meta-analysis and also to provide a better evidence for clinical practice.

METHODS

Seven databases will be searched in this study: The Cochrane Library, PubMed, Web of Science, the Chinese National Knowledge Infrastructure (CNKI), the Chinese Scientific Journal Database (CSJD), the Chinese Biomedical Literature Database (CBM), and Wanfang DATA. The following search terms will be used: (Huangqi OR Huang Qi OR Astragalus OR radix astragali) AND (acute myocardial infaction OR myocardial infaction OR AMI) AND (randomized controlled trial OR RCT OR randomized). No language limitations and the searches will be conducted up to March, 2019.

INCLUSION CRITERIA

randomized controlled trial (RCT) of Astragalus (Huangqi) preparation in patients with AMI. Main outcome measures will be left ventricular end systolic volume (LVESV), left ventricular end diastolic volume (LVEDV), left ventricular ejection fraction (LVEF), left ventricular mass index (LVMI), recanalization rate, mortality rate, incidence of reperfusion arrhythmias, postinfarction angina pectoris, and re-infarction rate. Secondary outcome indicators were the incidence of adverse reactions and the effective rate of traditional Chinese medicine (TCM) treatment. Two independent reviewers will filter the literature and extract data which based to the Cochrane manual. The relevant data, including bias risk assessment, data synthesis, subgroup analysis, meta-analysis, and final meta-analysis, will be analyzed with RevMan 5.3 software. The funnel diagram will be used to evaluate the reported deviation, and the Egger test will be used to evaluate the symmetry of the funnel graph.

RESULTS

This systematic review study will provide a clear basis for evaluating the efficacy and safety of Astragalus (Huangqi) preparation with the treatment of AMI.

CONCLUSION

This study will provide an up-to-date evidence for evaluating the efficacy and safety of Astragalus (Huangqi) preparation.

PROSPERO REGISTRATION NUMBER

CRD42019124843.

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.

Opioid receptors and cardioprotection - 'opioidergic conditioning' of the heart

Ischaemic heart disease (IHD) remains a major cause of morbidity/mortality globally, firmly established in Westernized or 'developed' countries and rising in prevalence in developing nations. Thus, cardioprotective therapies to limit myocardial damage with associated ischaemia-reperfusion (I-R), during infarction or surgical ischaemia, is a very important, although still elusive, clinical goal. The opioid receptor system, encompassing the δ (vas deferens), κ (ketocyclazocine) and μ (morphine) opioid receptors and their endogenous opioid ligands (endorphins, dynorphins, enkephalins), appears as a logical candidate for such exploitation. This regulatory system may orchestrate organism and organ responses to stress, induces mammalian hibernation and associated metabolic protection, triggers powerful adaptive stress resistance in response to ischaemia/hypoxia (preconditioning), and mediates cardiac benefit stemming from physical activity. In addition to direct myocardial actions, central opioid receptor signalling may also enhance the ability of the heart to withstand I-R injury. The δ- and κ-opioid receptors are strongly implicated in cardioprotection across models and species (including anti-infarct and anti-arrhythmic actions), with mixed evidence for μ opioid receptor-dependent protection in animal and human tissues. A small number of clinical trials have provided evidence of cardiac benefit from morphine or remifentanil in cardiopulmonary bypass or coronary angioplasty patients, although further trials of subtype-specific opioid receptor agonists are needed. The precise roles and utility of this GPCR family in healthy and diseased human myocardium, and in mediating central and peripheral survival responses, warrant further investigation, as do the putative negative influences of ageing, IHD co-morbidities, and relevant drugs on opioid receptor signalling and protective responses.

Phosphorylation of contractile proteins in response to alpha- and beta-adrenergic stimulation in neonatal cardiomyocytes

alpha- and beta-Adrenergic receptor agonists induce an inotropic response in the adult heart by promoting the phosphorylation of several regulatory proteins, including myosin-binding protein C (MyBP-C), cardiac troponin I (cTnI), and phospholamban (PLB). However, the adrenergic-induced phosphorylation of these proteins has not been characterized in the developing heart. Accordingly, we evaluated MyBP-C, cTnI, and PLB phosphorylation in cultured neonatal rat cardiomyocytes (NRCMs) after alpha- and beta-receptor activation with phenylephrine and isoproterenol. alpha-Receptor stimulation increased, whereas beta-receptor activation reduced MyBP-C phosphorylation. Isoelectric-focusing experiments indicated that the amount of monophosphorylated MyBP-C was sensitive to alpha-adrenergic activation, but diphosphorylated and triphosphorylated MyBP-C levels were largely unaffected. The phosphorylation of cTnI and PLB was consistent with the mechanism observed in adult hearts: alpha- and beta-Receptor stimulation phosphorylated both proteins. For cTnI, the greatest difference associated with beta-receptor activation was observed in the diphosphorylated state, whereas alpha-receptor activation was associated with a marked increase in the tetraphosphorylated protein and absence of the unphosphorylated state. Despite these apparent changes in cTnI and PLB phosphorylation, beta-receptor activation failed to alter calcium transients in NRCMs. Collectively, these findings suggest that, unlike cTnI and PLB, MyBP-C and inotropy are not coupled to beta-adrenergic stimulation in NRCMs. Therefore, cTnI and PLB probably play a more central role in modulating contractile function in NRCMs in response to catecholamines than does MyBP-C, and MyBP-C may have a structural role in stabilizing thick filament assembly rather than influencing cross-bridge formation in developing hearts.

Endogenous opiates and behavior: 2008

This paper is the 31st consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2008 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17).

Stimulation of kappa-opioid receptor reduces isoprenaline-induced cardiac hypertrophy and fibrosis

The aim of the present study was to determine whether U50,488H (a selective kappa-opioid receptor agonist) inhibits cardiac hypertrophy and fibrosis induced by beta-adrenoceptor stimulation in a rat model. Cardiac hypertrophy and fibrosis were developed by intraperitoneal administration of isoprenaline (ip. 3.0 mg/kg/day,14 days). In the isoprenaline-treated group, heart weight and heart-to-body ratio increased significantly. Hypertrophic alterations were observed in light micrographs of tissue and transmission electron micrographs of myocardial ultra structures. Increases in heart weight, heart-to-body ratio, diameter of cardiomyocytes, and morphological hypertrophic alterations induced by isoprenaline were significantly attenuated by U50,488H(i.p. 1.25 mg/kg/day). Growth of cardiomyocytes was induced by incubating with isoprenaline (10(-6) mol/l), which resulted in an increase in optical density (OD) values. The increased OD value was attenuated by U50,488H(10(-7) mol/l-10(-5) mol/l) in a dose dependent manner. Animals receiving administration of isoprenaline displayed significant fibrosis. The extent of isoprenaline induced left ventricular fibrosis was dramatically reduced in U50,488H treated animals. Increased cardiac fibroblast proliferation and collagen synthesis induced by isoprenaline, as evidenced by increased OD value, (3)H-thymidine, and (3)H-proline incorporation, were significantly reduced in the U50,488H treated group. The specific extracellular matrix proteins, including type I, type III collagen and fibronectin, which increased after administration of isoproterenol, were also attenuated by U50,488H. The abovementioned effects of U50,488H were completely abolished by nor-BNI (nor-binaltorphimine), a selective kappa-opioid receptor antagonist. The enhanced intracellular Ca(2+) transient and L-type Ca(2+) current elicited by isoprenaline in cardiomyocytes were significantly inhibited by U50,488H. This study provides the first morphological evidence of the inhibitory effect of U50,488H on isoprenaline-induced cardiac hypertrophy and fibrosis via kappa-opioid receptor stimulation.