Role of cardiac β1-adrenergic and A1-adenosine receptors in severe arrhythmias related to Parkinson's disease

Abstract Aims Although reduced life expectancy in Parkinson's Disease (PD) patients has been related to severe cardiac arrhythmias due to autonomic dysfunctions, its molecular mechanisms remain unclear. To investigate the role of cardiac β1-Adrenergic (β1AR) and A1-Adenosine (A1R) receptors in these dysfunctions, the pharmacological effects of stimulation of cardiac β1AR (isoproterenol, ISO), in the absence and presence of cardiac β1AR (atenolol, AT) or A1R (1,3-dipropyl-8-cyclopentyl xanthine, DPCPX) blockade, on the arrhythmias induced by Ischemia/Reperfusion (CIR) in an animal PD model were studied. Methods PD was produced by dopaminergic lesions (confirmed by immunohistochemistry analysis) caused by the injection of 6-hydroxydopamine (6-OHDA, 6 μg) in rat striatum. CIR was produced by a surgical interruption for 10 min followed by reestablishment of blood circulation in the descendent left coronary artery. On the incidence of CIR-Induced Ventricular Arrhythmias (VA), Atrioventricular Block (AVB), and Lethality (LET), evaluated by Electrocardiogram (ECG) analysis, the effects of intravenous treatment with ISO, AT and DPCPX (before CIR) were studied. Results VA, AVB and LET incidences were significantly higher in 6-OHDA (83%, 92%, 100%, respectively) than in control rats (58%, 67% and 67%, respectively). ISO treatment significantly reduced these incidences in 6-OHDA (33%, 33% and 42%, respectively) and control rats (25%, 25%, 33%, respectively), indicating that stimulation of cardiac β1AR induced cardioprotection. This response was prevented by pretreatment with AT and DPCPX, confirming the involvement of cardiac β1AR and A1R. Conclusion Pharmacological modulation of cardiac β1AR and A1R could be a potential therapeutic strategy to reduce severe arrhythmias and increase life expectancy in PD patients.

Cardiovascular protective properties of gastrodin

Cardiovascular diseases cause significant morbidity and mortality worldwide, incurring a major public health burden. Gastrodia elata Blume is a traditional Chinese herbal medicine that has been widely used to treat central nervous system and cardiovascular diseases. Gastrodin, as the major active component in Gastrodia elata Blume, can confer protection against cardiovascular diseases. In this review, we summarize the anti-inflammatory actions, anti-cardiac hypertrophy, anti-hypertension, anti-atherosclerosis, and angiogenic effects of gastrodin, as well as its protective effects on vascular cells and against myocardial ischemia-reperfusion injury. The medical potential of gastrodin in diabetes-related cardiovascular diseases is also discussed.

Cardioprotective mechanism of SGLT2 inhibitor against myocardial infarction is through reduction of autosis

Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce cardiovascular mortality in patients with diabetes mellitus but the protective mechanism remains elusive. Here we demonstrated that the SGLT2 inhibitor, Empagliflozin (EMPA), suppresses cardiomyocytes autosis (autophagic cell death) to confer cardioprotective effects. Using myocardial infarction (MI) mouse models with and without diabetes mellitus, EMPA treatment significantly reduced infarct size, and myocardial fibrosis, thereby leading to improved cardiac function and survival. In the context of ischemia and nutritional glucose deprivation where autosis is already highly stimulated, EMPA directly inhibits the activity of the Na+/H+ exchanger 1 (NHE1) in the cardiomyocytes to regulate excessive autophagy. Knockdown of NHE1 significantly rescued glucose deprivation-induced autosis. In contrast, overexpression of NHE1 aggravated the cardiomyocytes death in response to starvation, which was effectively rescued by EMPA treatment. Furthermore, in vitro and in vivo analysis of NHE1 and Beclin 1 knockout mice validated that EMPA's cardioprotective effects are at least in part through downregulation of autophagic flux. These findings provide new insights for drug development, specifically targeting NHE1 and autosis for ventricular remodeling and heart failure after MI in both diabetic and non-diabetic patients.

Referred Somatic Hyperalgesia Mediates Cardiac Regulation by the Activation of Sympathetic Nerves in a Rat Model of Myocardial Ischemia / 神经科学通报·英文版

Myocardial ischemia (MI) causes somatic referred pain and sympathetic hyperactivity, and the role of sensory inputs from referred areas in cardiac function and sympathetic hyperactivity remain unclear. Here, in a rat model, we showed that MI not only led to referred mechanical hypersensitivity on the forelimbs and upper back, but also elicited sympathetic sprouting in the skin of the referred area and C8-T6 dorsal root ganglia, and increased cardiac sympathetic tone, indicating sympathetic-sensory coupling. Moreover, intensifying referred hyperalgesic inputs with noxious mechanical, thermal, and electro-stimulation (ES) of the forearm augmented sympathetic hyperactivity and regulated cardiac function, whereas deafferentation of the left brachial plexus diminished sympathoexcitation. Intradermal injection of the α2 adrenoceptor (α2AR) antagonist yohimbine and agonist dexmedetomidine in the forearm attenuated the cardiac adjustment by ES. Overall, these findings suggest that sensory inputs from the referred pain area contribute to cardiac functional adjustment via peripheral α2AR-mediated sympathetic-sensory coupling.

Trascendencia de los exosomas en la cardiología: heraldos de la cardioprotección / Significance of exosomes in cardiology: heralds of cardioprotection

Resumen Los exosomas tienen un papel clave en la comunicación intercelular. Debido a sus múltiples interacciones, estas estructuras cumplen con el papel de «mensajeros¼ de forma dinámica, transportando su contenido a células blanco específicas y generando nuevas señales celulares. En este artículo se describen algunas de las proteínas, lípidos y ácidos nucleicos que son transportados por estas vesículas y que se han relacionado con cardioprotección, con la finalidad de proporcionar información y generar interés sobre la relevancia de los exosomas como posibles blancos diagnósticos y terapéuticos.

Abstract Exosomes have a key role in intercellular communication. Due to their multiple interactions, these structures fulfill the role of “messengers” in a dynamic way, transporting their content to target-specific cells and generating new cellular signals. This article describes some of the proteins, lipids and nucleic acids that are transported by these vesicles and that have been related to cardioprotection, in order to provide information and generate interest in the relevance of exosomes as possible diagnostic and therapeutic targets.

Protective effect of hemoglobin oxygen carrier with different oxygen affinity on isolated rat hearts / 中国输血杂志

【Objective】 To explore the protective effects of hemoglobin base on oxygen carries (HBOCs) with different oxygen affinity on isolated rat hearts. 【Methods】 Using Langendorff isolated heart perfusion model, 45 adult male SD rats (SPF grade), perfused with 30 min KH solution baseline, were randomly divided into sham operation group and control group: St. Thomas (STS) solution perfusion volume was 3mL/100g body weight; high P50 HBOCs group: [STS + high P50 HBOCs (P50=35.0 mmHg, 2.5 mg/100 g) product] perfusion volume was 3mL/100g body weight; medium P50 HBOCs group: [STS + medium P50HBOCs (P50=26.5.0 mmHg, 2.5 mg/100 g) product] perfusion volume was 3 mL/100 g body weight; low P50 HBOCs group: [STS + low P50 HBOCs (P50=11.0 mmHg, 2.5 mg/100 g) product] perfusion volume was 3mL/100g body weight, and the heart was arrested and placed in a 37℃ water bath to make the heart ischemic for 35 minutes, and then reperfused for 2 hours. The left ventricular development pressure (LVDevP), left ventricular end diastolic pressure (LVEDP), the rate of change of left ventricular pressure (LVPCR) and heart rate (HR) in the rat heart during reperfusion were observed and recorded. 1 min perfusion fluid from each rat in the basic and reperfusion phase was taken, and blood gas analyzer was used to measure the blood gas indexes of rats, and the myocardial injury marker enzymes [cardiac enzyme creatine kinase (CK-MB), lactate dehydrogenase (LDH) and the release of α-hydroxybutyrate dehydrogenase (α-HBDH)] were measured by ELISA kit. 【Results】 The cardiac function and the release of myocardial enzymes in the 5 groups of rats in the basal cardiac perfusion stage were similar (P>0.05). However, in the reperfusion stage, except for the insignificant changes in HR (P>0.05), the heart LVDevP (mmHg) of the three P50 HBOCs groups and the control group were 10.69±3.65 vs 8.50±2.88, 23.26 ±5.62 vs 8.50±2.88, 35.60±3.82 vs 8.50±2.88, LVEDP (mmHg) were 43.34±8.08 vs 54.64±7.42, 39.43±8.30 vs 54.64±7.42, 31.46±4.11 vs 54.64±7.42, dp/dt were 12.09±9.96 vs 6.09±0.98, 25.65±8.87 vs 6.08±0.98, 35.32±9.33 vs 6.09±0.98, -dp/dt were 17.53±11.28 vs 11.39±2.16, 28.80±13.70 vs 11.39±2.16, 43.36±3.83 vs 11.39±2.16, respectively (all P<0.05); the rebound situation and the release of CK-MB, LDH, and α-HBDH in the three P50 HBOCs groups were better than those in the control group (P<0.05). Among the three P50HBOCs products, the low P50HBOCs group had the best cardiac function indexes. The myocardial enzyme indexes of the high, medium and low HBOCs groups were CK-MB (ng/mL): 110.47±4.04, 90.2±2.46, 77.1±3.51; LDH (U/L): 162.23±7.71, 135.13±23.69, 92.20±4.21; a-HBDH (U/L): 228.00±8.03, 172.30±8.99, 131.00±2.02. 【Conclusion】 STS solution containing HBOCs products can improve the function of the reperfused heart at normal temperature ischemia for 35 min and 2 h reperfusion, and reduce heart damage. The STS solution containing low P50 HBOCs has the most obvious protective effect in rat isolated heart perfusion.

Oroxylum indicum root bark extract prevents doxorubicin-induced cardiac damage by restoring redox balance

Background: Oroxylum indicum Vent., a Dasamula plant used in Ayurveda possesses antioxidantproperties.Objectives: To evaluate the cardioprotective effect of 70% methanolic extract of O. indicum Vent. root bark(OIM) against doxorubicin induced cardiomyopathy in female Sprague Dawley rats.Materials and methods: Cardiotoxicity was induced by intra-peritoneal injection of doxorubicin 30 mg/kg body weight (b.w.) for 4 consecutive days after a ten-day pre-treatment of animals with OIM at200 mg/kg b.w. and 400 mg/kg b.w (p.o.). Drug treatment continued up to day 14. Probucol, orallyadministered at a dose of 20 mg/kg b.w. served as standard. ECG was recorded. The animals weresacrificed on day 15 and comparative analysis of serum marker levels of creatine phosphokinase (CPK),lactate dehydrogenase (LDH), Serum Glutamate Oxaloacetate Transaminase (SGOT), Serum GlutamatePyruvate Transaminase (SGPT), tissue antioxidant status based on Superoxide Dismutase (SOD),Glutathione Peroxidase (GPx), reduced Glutathione (GSH) and lipid peroxidation (LPO) was carried out.Histopathological examination was carried out using hematoxylineeosin staining.Results: ECG records of OIM treated animals showed normal pattern, in comparison to the control withST depression and arrhythmia in cardiogram. Tissue antioxidant profile (SOD, GSH and GPx) wassignificantly (p < 0.01) elevated in the cardiac tissue of treated group in dose-dependent manner; lipidperoxidation level was found to decrease with treatment. Comparative analysis of serum markers e CPK,LDH, SGOT and SGPT e among untreated control, standard and extract treated groups revealed that OIMextract at 400 mg/kg b.w. dose significantly reduced the levels (p < 0.01). Histological analysis revealednormal myocardial architecture in OIM treated groups. HPTLC fingerprint of OIM revealed 8 bands anddetected the presence of chrysin, apigenin and quercetin.Conclusion: O. indicum root bark shows marked cardio-protective activity, possibly due to the presence ofantioxidant compounds acting synergistically.© 2017 Transdisciplinary University, Bangalore and World Ayurveda Foundation. Publishing Services byElsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Late cardiac perconditioning by phenylephrine in an isolated rat heart model is mediated by mitochondrial potassium channels

The present study was designed to investigate the effect of early and late administration of phenylephrine during ischemia against regional ischemia-reperfusion injuries in an isolated rat heart model. All animals were randomly divided into experimental groups: (I) IR (Ischemic/ reperfusion): the hearts underwent 35 min of regional ischemia followed by 60 min of reperfusion; (II) 5HD-IR-0: the hearts were perfused for 5 min with 5HD (5-hydroxydecanoate, specific mKATP channel blocker, 100 µM) at the onset of regional ischemia; (III) 5HD-IR-20: the hearts were perfused for 5 min with 5HD 20 min after regional ischemia; (IV) PE-IR-10: the hearts were perfused for 5 min with phenylephrine 10 min after regional ischemia; (V) PE-IR-30: the hearts were perfused for 5 min with phenylephrine (100 µM) 30 min after regional ischemia; (VI) PE-5HD-IR-10 group: the hearts were perfused for 5 min with 5HD at the onset of regional ischemia after which phenylephrine was administrated as in group IV; and (VII) PE-5HD-IR-30: the hearts were perfused for 5 min with 5HD 20 min after the ischemia and then phenylephrine was administrated as in group V. The hemodynamic parameters were recorded throughout the experiment. Ischemia-induced arrhythmias, myocardial infarct size (IS), creatin kinase-MB isoenzyme (CK-MB), plasma lactate dehydrogenase (LDH) activities, and coronary blood flow (CBF) were measured in all animals. Perfusion of phenylephrine 30 min after the regional ischemia curtailed the myocardial infarct size, reduced CK-MB, and improved cardiac function and CBF. Administration of 5HD 30 min after the ischemia abolished cardioprotective effects of phenylephrine in the late phase. These results suggest the involvement of mKATP in the mechanism of phenylephrine-induced late preconditioning.

Protective effect of cardiomyopeptide on doxorubicin induced cell injury in H9c2 cardiomyocytes / 中国药理学通报

Aim To investigate the effect of cardio-myopeptide on doxorubicin-induced toxicity on H9c2 cardiomyoblasts and its related mechanism. Methods H9c2 cells were respectively pretreated with different concentrations(0, 10, 20, 40 mg ∗ L-1) of cardio-myopeptide for 6 h,8 h, 12 h. Cell viability was determined by MTT assay. The protein expression of caspase-3, Bcl-2, Bax, IGF-1R and IGFBP-3 were detected by Western blot. Results Cardiomyopeptide protected H9c2 cardiomyocytes from doxorubicin induced apoptosis in a dose-and time-dependent manner. The half maximal inhibitory concentration (IC50) was shifted from(1.2 ±0.4) umol • L-1 to(2.3 ±0.2) jimol • L-1 The expression of Bcl-2, IGF-1R was up-regulated , and Bax, IGFBP-3 and caspase-3 decreased in H9c2 cells. Conclusions Cardiomyopeptide could prevent from apoptosis induced by doxorubicin in H9c2 cells via increasing expression of IGF-1R, thus up-reg-ulation of the antiapoptotic protein Bcl-2 and inhibiting caspase-3 activity.

Neurogenic stress cardiomyopathy: What do we need to know

The interaction between the heart and brain is complex and integral to the maintenance of normal cardiovascular function. Even in the absence of coronary disease, acute neuronal injury can induce a variety of cardiac changes. Recent neuroimaging data revealed a network including the insular cortex, anterior cingulate gyrus, and amygdala playing a crucial role in the regulation of central autonomic nervous system. Damage in these areas has been associated with arrhythmia, myocardial injury, higher plasma levels of brain natriuretic peptide, catecholamines, and glucose. Some patients after brain injury may die due to occult cardiac damage and functional impairment in the acute phase. Heart failure adversely influences acute stroke mortality. Troponin and NT-proBNP are elevated in acute brain injury patients, in response to the activated renin–angiotensin–aldosterone system and other neurohumoral changes, as a protective mechanism for sympathoinhibitory activity. Such patients have been shown to be associated with higher short- and long-term mortality. While thrombolysis, neuroprotection, and other measures, alone or in combination, may limit the cerebral damage, attention should also be directed toward the myocardial protection. Early administration of cardioprotective medication aimed at reducing increased sympathetic tone may have a role in myocardial protection in stroke patients. For a full understanding of the brain–heart control, the consequences of disruption of this control, the true incidence of cardiac effects of stroke, and the evidence-based treatment options further research are needed.

Electroacupuncture for myocardial ischemia injury in rats via AMPK-HDAC5-HIF-1α signaling / 中国针灸

OBJECTIVE@#To explore the impact of electroacupuncture (EA) on the AMPKα-HDAC5-HIF-1α signaling in the heart of the rats with myocardial ischemia (MI) via detecting the expressions of AMP-activated protein kinase α (AMPKα), histone deacetylase 5 (HDAC5), hypoxia inducible factor (HIF-1α) and vascular endothelial growth factor (VEGF).@*METHODS@#Thirty-six healthy male SD rats were randomized into a sham operation group (6 rats), a sham + EA group (6 rats), a model group (12 rats) and an EA group (12 rats). We ligated the left anterior descending artery (LAD) for MI model, and exposed the heart of rats after opening the chest without ligation for the rats in the sham operation gorup and the sham + EA group. On the 2nd day after LAD ligation, EA was applied at "Neiguan" (PC 6) with 2 Hz/15 Hz and 1.5-2 mA for 30 min in the EA group and sham+EA group, once a day for 4 days. The same fixation was used in the sham operation group and the model group, without EA. Myocardial infarction area was observed by TTC staining and serum cardiac troponin T (cTnT) was detected by radioimmunoassay. The expression of VEGF mRNA was detected by real time PCR. The protein expressions of AMPKα, HDAC5, HIF-1α and VEGF were detected by western blot.@*RESULTS@#Compared with the sham operation group, 4 days after LAD ligation, the myocardial infarction was obvious and the expression of serum cTnT increased in the model group (0.05). After EA for 4 days, the myocardial infarction area and cTnT expression decreased in the EA group (both <0.01); the VEGF mRNA and protein expressions and AMPKα, HDAC5, HIF-1α protein expressions increased (<0.05, <0.01).@*CONCLUSION@#EA could regulate the AMPKα-HDAC5-HIF-1α signaling in myocardial tissue, which may activate VEGF expression for angiogenesis signaling, reduce myocardial infarction area so as to achieve cardioprotective effect.

Role of ERK signaling protein in morphine preconditioning reducing global ischemia-reperfusion injury in isolated rat hearts / 中国药理学通报

Aim To observe the role of ERK signaling protein in morphine preconditioning reducing global ischemia-reperfusion injury in isolated rat hearts.Methods Adult male Sprague-Dawley rats were distributed into six groups (n =10 for each) using a random number table:control group (CON),ischemia-reperfusion group (I/R),ischemia preconditioning group (IPC),morphine preconditioning group at the concentration of 1 μmol · L-1 (MPC),ERK inhibitor PD98059 + MPC (MPD),and group of ERK inhibitor-PD98059 (PD).The isolated rat hearts were treated on a Langendorff perfusion apparatus system.The coronary effluent was collected at 15 min of equilibration (baseline),5 and 10 min of reperfusion for detection of the activity of LDH.Meanwhile,a water-filled balloon was inserted into the left ventricular for continuous LVDP measurement.The IS and AAR and IS/AAR ratios were observed by TTC.Western blot was used to examine the level of phosphorylated ERK in myocardium.Results As compared with the I/R group,MPC significantly decreased IS and IS/AAR ratio as well as LDH activities at 5 min and 10 min of reperfusion,but improved the LVDP at the end of reperfusion.Moreover,the phosphorylation level of ERK in myocardium was up-regulated by MPC.However,ERK inhibitor PD98059 could block the protective effects of MPC,as indicated by the increased IS and IS/AAR ratio,elevated LDH activity at the reperfusion of 5 and 10 min,and the suppressed LVDP at the end of reperfusion.Furthermore,the MPC-induced phosphorylation of ERK was also reversed by PD98059.Conclusion Morphine preconditioning may confer cardio-protection against the global ischemia-reperfusion injury in rat hearts through enhancing the phosphorylation of ERK.

How useful in the daily practice of nephrologists are the new antidiabetics with cadiovascular protection? / ¿Qué tan útiles en la práctica diaria para los nefrólogos son los nuevos antidiabéticos con protección cardiovascular?

Abstract In recent years, several new antidiabetic drugs have been developed, among which only two have demonstrated superiority in cardiovascular protection. They are liraglutide and empagliflozine, which belong, respectively, to GLP-1 RA and SGLT-2Í. These medications have also shown benefits in kidney protection. However, in a recent survey of the author among nephrologists in a large colombian city, it has been detected that most do not use these drugs. The greater resistance to the limitation in its use is due to the advanced stages of chronic kidney disease where they are contraindicated, but also to the anawareness of their potential benefits. In this regard, the nephrologists accepted they should learn more about these antidiabetic medicines, because the type of patient that is frequently attended in their consultation will undoubtly benefit, and considering they are obligated to handle the diabetic patient directly.

Resumen En los últimos años se han desarrollado nuevos fármacos antidiabéticos, entre los que sólo dos han demostrado superioridad en protección cardiovascular. Son liraglutida y empagliflozina, que pertenecen, respectivamente, a los grupos GLP-1 RA y SGLT-2Í. Estos medicamentos también han demostrado beneficios en nefroprotección. Sin embargo, en una reciente encuesta del autor entre nefrólogos, en una gran ciudad colombiana, se ha detectado que la mayoría no utilizan estos fármacos. La mayor resistencia a su uso se debe a consideraciones sobre su restricción en etapas avanzadas de la enfermedad renal crónica, pero también al desconocimiento de sus beneficios potenciales. Al respecto, los nefrólogos aceptaron que deberían aprender más acerca de estos medicamentos antidiabéticos, porque el tipo de paciente que frecuentemente asiste a su consulta sin duda se beneficiaría, y más teniendo en cuenta que por el gran número de diabéticos los nefrólogos están obligados a manejar directamente al paciente con esta patología.

Cardio- and hepato-protective potential of methanolic extract of Syzygium cumini (L.) Skeels seeds: A diabetic rat model study

Objective To evaluate the effect of methanolic extract of Syzygium cumini (L.) Skeels (S. cumini) seeds on the major organs in an animal model of diabetes through biochemical and histopathological studies. Methods The methanolic extracts of S. cumini seeds (100 and 200 mg/kg body weight) were administered to alloxan-induced diabetic rats daily, with fasting blood glucose levels being measured by glucometry at one-day interval for a duration of two weeks. Biochemical assays to evaluate changes in the functions of the heart, liver, pancreas and kidney were carried out. Histopathological changes in the diabetic rat organs (pancreas, liver, heart, kidney and spleen) were also observed after the 14 days of treatment with the extracts. Results Oral administration of methanolic extracts of S. cumini seeds (100 and 200 mg/kg body weight), with gliclazide as a positive control (25 mg/kg), showed beneficial effects including lowering blood glucose levels (P < 0.001), improved heart and liver functions, and hyperlipidemia due to diabetes. At 200 mg/kg, the extracts reversed cardiac and liver damage caused by alloxan. Conclusions In addition to the anti-hyperglycemic activity of methanolic extracts of S. cumini seeds, the extracts demonstrates potential to minimize cardiac and hepatic complications.

Role of endoplasmic reticulum stress in AstragalosideⅣ-induced cardioprotection in H9c2 cardiac cells / 中国药理学通报

Aim To explore the role of endoplasmic reticulum stress(ERS) in Astragaloside Ⅳ-induced cardioprotection in H9c2 cardiac cells, and to explore the potential mitochondrial mechanism.Methods Conventional culture was performed of rat heart tissue-derived H9c2 cells.Experiment was randomly divided into the control group, the ERS inducer 2-Deoxy-D-Glucose(2-DG) group, Astragaloside Ⅳ and 2-DG combination group, Astragaloside Ⅳ group.Confocal microscopy was used to observe the changes of TMRE fluorescence intensity so as to confirm the influence of ERS on the mitochondrial potential, and further speculate on the opening of the mitochondrial permeability transition pore(mPTP).Western blot analysis was applied to detect the expressions of ERS proteins GRP 78, GRP 94 and IRE1.Transmission electron microscopy was used to observe the ultrastructure of the cells.Results Different doses of 2-DG could mimic the mPTP opener atractyloside to induce the mPTP opening with the peak at 100 μmol·L-1;Astragaloside Ⅳ significantly reduced 2-DG-induced mPTP opening, the expression of GPR 78, GRP 94 and IRE1 and reduced injury of mitochondria and endoplasmic reticulum.Conclusions Endoplasmic reticulum stress could be induced by 2-DG.Astragaloside ⅳ-induced mitochondrial cardioprotection involves inhibition of the ERS through GRP 78, GRP 94 and IRE1 by prevention of the mPTP opening.

Progress on pharmacological research of cardioprotection by salidroside / 药物评价研究

By increasing the release of Ca2+ from sarcoplasmic reticulum in cardiomyocytes,salidroside elevates myocardial contraction,and by up-regulation of sarcoplasmic reticulum Ca2+-ATPase expression,and down-regulation ofcalcineurin expression to promote Ca2+ return to sarcoplasmic reticulum,salidroside obstructs Ca2+ overload-induced myocardial injury,and improves heart function.Salidroside inhibits lipid peroxidation,and increases activities of enzymatic antioxidants in heart tissue,and inhibits expression of inflammatory cytokines,and mitochondrial permeability transition pore opening,thus blocks myocardial apoptosis,by anti-oxidation and anti-inflammation;salidroside improves myocardial ischemia by up-regulation of hypoxia-inducible factor and vascular endothelial growth factor expression to promote angiogenesis in ischemic myocardium;salidroside improves respiratory function of mitochondria in myocardium by stimulating PGC-1 αt-NRF-1/NRF-2 signaling pathway to produce finally cardioprotective effect.These effects of salidroside are thought that are major mechanism of antagonizing cardiac injury induced by hypoxia,ischemia,ischemic-reperfusion,exhaustive exercise,chemicals,and biologic toxin.

Cardio-and hepato-protective potential of methanolic extract of Syzygium cumini (L.) Skeels seeds:A diabetic rat model study

Objective: To evaluate the effect of methanolic extract of Syzygium cumini (L.) Skeels (S. cumini) seeds on the major organs in an animal model of diabetes through biochemical and histopathological studies. Methods: The methanolic extracts of S. cumini seeds (100 and 200 mg/kg body weight) were administered to alloxan-induced diabetic rats daily, with fasting blood glucose levels being measured by glucometry at one-day interval for a duration of two weeks. Biochemical assays to evaluate changes in the functions of the heart, liver, pancreas and kidney were carried out. Histopathological changes in the diabetic rat organs (pancreas, liver, heart, kidney and spleen) were also observed after the 14 days of treatment with the extracts. Results: Oral administration of methanolic extracts of S. cumini seeds (100 and 200 mg/kg body weight), with gliclazide as a positive control (25 mg/kg), showed beneficial effects including lowering blood glucose levels (P < 0.001), improved heart and liver functions, and hyperlipidemia due to diabetes. At 200 mg/kg, the extracts reversed car-diac and liver damage caused by alloxan. Conclusions: In addition to the anti-hyperglycemic activity of methanolic extracts of S. cumini seeds, the extracts demonstrates potential to minimize cardiac and hepatic complications.

Role of Rho-kinase in remote ischemicpostconditioning against myocardial ischemia/reperfusion injury / 中国药理学通报

Aim To explore the role of Rho-kinase in remote ischemic postcondi-tioning and its possible mechanism.Methods Thirty male Sprague-Dawley rats were divided into five groups(n=6): sham group(Sham), ischemia/reperfusion group(I/R), remote ischemic postconditioning group(RIPostC), I/R with Rho-kinase inhibitor fasudil group(I/R+Fas) and RIPostC with Rho-kinase activator lysophosphatidic acid group(RIPostC+LPA).Throughout the whole process of experiment, mean arterial pressure(MAP), heart rate(HR) and Ⅱ lead electrocardiogram were continuously monitored.At the end of the reperfusion, plasma creatine kinase(CK) and lactate dehydrogenase(LDH) were measured.Myocardial histopathologic changes were observed by hematoxylin and eosin(HE) staining.Infarct size was measured using 2,3,5-triphenyltetrazolium chloride(TTC) staining.The expressions of phospho-myosin light chain(p-MLC) were detected with Western blot analysis.Results Compared with Sham group, the MAP and HR of other groups decreased, while the amplitude of ST segment increased.Compared with I/R group, MAP and HR increased, the amplitude of ST segment decreased, plasma CK and LDH activity decreased, myocardial pathological morphology and infarct size were improved significantly, infiltration of inflammatory cells was reduced, and the expression of p-MLC decreased in RIPostC and I/R+Fas group.Compared with RIPostC group, RIPostC+LPA group attenuated the effects of RIPostC, and the recovery of the above indicators were inhibited.Conclusion Rho-kinase signaling pathway might mediate remote ischemia postconditioning against myocardial ischemia/reperfusion injury.

Neurogenic pathways in remote ischemic preconditioning induced cardioprotection: Evidences and possible mechanisms

Remote ischemic preconditioning (RIPC) is an intrinsic phenomenon whereby 3~4 consecutive ischemia-reperfusion cycles to a remote tissue (noncardiac) increases the tolerance of the myocardium to sustained ischemiareperfusion induced injury. Remote ischemic preconditioning induces the local release of chemical mediators which activate the sensory nerve endings to convey signals to the brain. The latter consequently stimulates the efferent nerve endings innervating the myocardium to induce cardioprotection. Indeed, RIPC-induced cardioprotective effects are reliant on the presence of intact neuronal pathways, which has been confirmed using nerve resection of nerves including femoral nerve, vagus nerve, and sciatic nerve. The involvement of neurogenic signaling has been further substantiated using various pharmacological modulators including hexamethonium and trimetaphan. The present review focuses on the potential involvement of neurogenic pathways in mediating remote ischemic preconditioning-induced cardioprotection.