Aurora kinases inhibitors, including ZM447439 (ZM), which suppress cell division, have attracted a great deal of attention as potential novel anti-cancer drugs. Several recent studies have confirmed the anti-cancer effects of ZM in various cancer cell lines. However, there have been no studies regarding the cardiac safety of this agent. We performed several cytotoxicity, invasion and migration assays to examine the anti-cancer effects of ZM. To evaluate the potential effects of ZM on cardiac repolarisation, whole-cell patch-clamp experiments were performed with human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and cells with heterogeneous cardiac ion channel expression. We also conducted a contractility assay with rat ventricular myocytes to determine the effects of ZM on myocardial contraction and/or relaxation. In tests to determine in vitro efficacy, ZM inhibited the proliferation of A549, H1299 (lung cancer), MCF-7 (breast cancer) and HepG2 (hepatoma) cell lines with IC₅₀ in the submicromolar range, and attenuated the invasive and metastatic capacity of A549 cells. In cardiac toxicity testing, ZM did not significantly affect I(Na), I(Ks) or I(K1), but decreased I(hERG) in a dose-dependent manner (IC₅₀: 6.53 µM). In action potential (AP) assay using hiPSC-CMs, ZM did not induce any changes in AP parameters up to 3 µM, but it at 10 µM induced prolongation of AP duration. In summary, ZM showed potent broad-spectrum anti-tumor activity, but relatively low levels of cardiac side effects compared to the effective doses to tumor. Therefore, ZM has a potential to be a candidate as an anti-cancer with low cardiac toxicity.
Action Potentials ; Animals ; Antineoplastic Agents ; Aurora Kinases ; Cardiotoxicity ; Cell Division ; Cell Line ; Humans ; In Vitro Techniques ; Ion Channels ; Muscle Cells ; Myocardial Contraction ; Myocytes, Cardiac ; Phosphotransferases ; Rats ; Relaxation

A heart simulator, UT-Heart, is a finite element model of the human heart that can reproduce all the fundamental activities of the working heart, including propagation of excitation, contraction, and relaxation and generation of blood pressure and blood flow, based on the molecular aspects of the cardiac electrophysiology and excitation-contraction coupling. In this paper, we present a brief review of the practical use of UT-Heart. As an example, we focus on its application for predicting the effect of cardiac resynchronization therapy (CRT) and evaluating the proarrhythmic risk of drugs. Patient-specific, multiscale heart simulation successfully predicted the response to CRT by reproducing the complex pathophysiology of the heart. A proarrhythmic risk assessment system combining in vitro channel assays and in silico simulation of cardiac electrophysiology using UT-Heart successfully predicted druginduced arrhythmogenic risk. The assessment system was found to be reliable and efficient. We also developed a comprehensive hazard map on the various combinations of ion channel inhibitors. This in silico electrocardiogram database (now freely available at http://ut-heart.com/) can facilitate proarrhythmic risk assessment without the need to perform computationally expensive heart simulation. Based on these results, we conclude that the heart simulator, UT-Heart, could be a useful tool in clinical medicine and drug discovery.
Blood Pressure ; Cardiac Electrophysiology ; Cardiac Resynchronization Therapy ; Cardiotoxicity ; Clinical Medicine ; Computer Simulation ; Drug Discovery ; Drug Evaluation, Preclinical ; Electrocardiography ; Heart ; Humans ; In Vitro Techniques ; Ion Channels ; Models, Cardiovascular ; Relaxation ; Risk Assessment

BACKGROUND AND OBJECTIVES: Bone marrow-derived mesenchymal stem cells (BM-MSCs) are adult multipotent non-haematopoietic stem cells that have regeneration potential. The current study aimed to detect the ability of BM-MSCs to improve kidney and cardiac functions in adult rats with established chronic kidney disease. METHODS: Rats were divided into sham-operated control, untreated sub totally nephrectomised and treated sub totally nephrectomised groups. Body weight, kidney and cardiac tissue weights, plasma creatinine and urea levels and arterial blood pressure were measured. ECG was recorded, and an in vitro isolated heart study was performed. Results: Stem cell treatment decreased the elevated plasma creatinine and urea levels and decreased systolic, diastolic and mean arterial blood pressure values. These changes were accompanied by a decrease in glomerular hypertrophy with apparent normal renal parenchyma. Additionally, BM-MSCs shortened Q-To and Q-Tc intervals, all time to peak tension values, the half relaxation value at 30 min of reperfusion and the contraction time at 15 and 30 min of reperfusion. Moreover, stem cell treatment significantly increased the heart rate, QRS voltage, the peak tension at the 15- and 30-min reperfusion time points and the peak tension per left ventricle at the 30-min reperfusion time point compared to the pre-ischaemia baseline. BM-MSCs resolve inter muscular oedema and lead to the re-appearance of normal cardiomyocytes. This improvement occurs with the observations of BM-MSCs in renal and heart tissues. CONCLUSIONS: BM-MSCs can attenuate chronic kidney disease progression and the associated cardiac electrophysiological and inotropic dysfunction.
Adult ; Animals ; Arterial Pressure ; Body Weight ; Creatinine ; Electrocardiography ; Heart Rate ; Heart Ventricles ; Heart ; Humans ; Hypertrophy ; In Vitro Techniques ; Kidney ; Mesenchymal Stromal Cells ; Myocytes, Cardiac ; Nephrectomy ; Plasma ; Rats ; Regeneration ; Relaxation ; Renal Insufficiency, Chronic ; Reperfusion ; Stem Cells ; Urea ; Weights and Measures

BACKGROUND: Apart from its blood pressure-lowering effect by blocking the renin-angiotensin-aldosterone system, telmisartan, an angiotensin II type 1 receptor blocker (ARB), exhibits various ancillary effects including cardiovascular protective effects in vitro. Nonetheless, the protective effects of telmisartan in cerebrocardiovascular diseases are somewhat variable in large-scale clinical trials. Dysregulation of endothelial nitric oxide (NO) synthase (eNOS)-derived NO contributes to the developments of various vascular diseases. Nevertheless, the direct effects of telmisartan on endothelial functions including NO production and vessel relaxation, and its action mechanism have not been fully elucidated. Here, we investigated the mechanism by which telmisartan regulates NO production and vessel relaxation in vitro and in vivo. METHODS: We measured nitrite levels in culture medium and mouse serum, and performed inhibitor studies and western blot analyses using bovine aortic endothelial cells (BAECs) and a hyperglycemic mouse model. To assess vessel reactivity, we performed acetylcholine (ACh)-induced vessel relaxation assay on isolated rat aortas. RESULTS: Telmisartan decreased NO production in normoglycemic and hyperglycemic BAECs, which was accompanied by reduced phosphorylation of eNOS at Ser¹¹⁷⁹ (p-eNOS-Ser¹¹⁷⁹). Telmisartan increased the expression of protein phosphatase 2A catalytic subunit (PP2Ac) and co-treatment with okadaic acid completely restored telmisartan-inhibited NO production and p-eNOS-Ser¹¹⁷⁹ levels. Of the ARBs tested (including losartan and fimasartan), only telmisartan decreased NO production and p-eNOS-Ser¹¹⁷⁹ levels, and enhanced PP2Ac expression. Co-treatment with GW9662 had no effect on telmisartan-induced changes. In line with in vitro observations, telmisartan reduced serum nitrite and p-eNOS-Ser¹¹⁷⁹ levels, and increased PP2Ac expression in high fat diet-fed mice. Furthermore, telmisartan attenuated ACh-induced rat aorta relaxation. CONCLUSION: We demonstrated that telmisartan inhibited NO production and vessel relaxation at least in part by PP2A-mediated eNOS-Ser¹¹⁷⁹ dephosphorylation in a peroxisome proliferator-activated receptor γ-independent manner. These results may provide a mechanism that explains the inconsistent cerebrocardiovascular protective effects of telmisartan.
Acetylcholine ; Animals ; Aorta ; Blotting, Western ; Catalytic Domain ; Endothelial Cells ; In Vitro Techniques ; Losartan ; Mice ; Mice, Obese ; Nitric Oxide Synthase Type III ; Nitric Oxide ; Okadaic Acid ; Peroxisomes ; Phosphorylation ; Protein Phosphatase 2 ; Rats ; Receptor, Angiotensin, Type 1 ; Relaxation ; Renin-Angiotensin System ; Vascular Diseases

Mindfulness is a process in which all thoughts, feelings, sensations, and all phenomena that happen to me are uncritically recognized as they are, so that they are eventually accepted and released without identifying or automatically responding to them. The clinical effects of mindfulness-based therapy have already been demonstrated in several studies. However, consistent results have not been reported for the mechanism of mindfulness-based treatment. Thus, this review aimed to describe a systematic review of the literature and research on the mechanisms of mindfulness-based interventions. Experienced meditators showed a physiological change in a ‘wakeful hypometabolic state’ during mindfulness meditation. In mindfulness meditation, it is known that certain areas other than brain activation during relaxation are additionally activated, particularly activation of fronto-limbic and fronto-parietal neural networks. The psychological mechanisms include meta-cognitive awareness, emotion regulation, reduction of automatic and self-referential thinking, concentration control, self-compassion, improvement of value clarification and self-regulation, exposure, extinction, and reconsolidation. Of the brain regions with changes in activity associated with mindfulness meditation, prefrontal cortex, the default mode network including cortical midline structures were associated with emotion regulation, concentration control, and reduction of automatic and self-referential thinking. In addition, brain regions associated with mindfulness meditation have been reported in the hippocampus, amygdala, and medical frontal cortices associated with memory reconsolidation and fear extinction. Thus, mindfulness-based interventions have a psychological and neurobiological effect with a special mechanism different from other psychological interventions, so that mindfulness based intervention can be an effective therapeutic intervention with a different mechanism from other psychological techniques.
Amygdala ; Brain ; Frontal Lobe ; Hippocampus ; Meditation ; Memory ; Mindfulness ; Prefrontal Cortex ; Psychological Techniques ; Relaxation ; Self-Control ; Sensation ; Thinking

OBJECTIVETo investigate whether the methanol extract of Berberis amurensis Rupr. (BAR) augments penile erection using in vitro and in vivo experiments.

METHODSThe ex vivo study used corpus cavernosum strips prepared from adult male New Zealand White rabbits. In in vivo studies for intracavernous pressure (ICP), blood pressure, mean arterial pressure (MAP), and increase of peak ICP were continuously monitored during electrical stimulation of Sprague-Dawley rats.

RESULTSPreconstricted with phenylephrine (PE) in isolated endotheliumintact rabbit corus cavernosum, BAR relaxed penile smooth muscle in a dose-dependent manner, which was inhibited by pretreatment with NG-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor, and H-[1,2,4]-oxadiazole-[4,3-α]-quinoxalin-1-one, a soluble guanylyl cclase inhibitor. BAR significantly relaxed penile smooth muscles dose-dependently in ex vivo, and this was inhibited by pretreatment with L-NAME H-[1,2,4]-oxadiazole-[4,3-α]-quinoxalin-1-one. BAR-induced relaxation was significantly attenuated by pretreatment with tetraethylammonium (TEA, P<0.01), a nonselective K channel blocker, 4-aminopyridine (4-AP, P<0.01), a voltage-dependent K channel blocker, and charybdotoxin (P<0.01), a large and intermediate conductance Ca sensitive-K channel blocker, respectively. BAR induced an increase in peak ICP, ICP/MAP ratio and area under the curve dose dependently.

CONCLUSIONBAR augments penile erection via the nitric oxide/cyclic guanosine monophosphate system and Ca sensitive-K (BK and IK) channels in the corpus cavernosum.

Animals ; Area Under Curve ; Berberis ; chemistry ; Blood Pressure ; drug effects ; Cyclic GMP ; metabolism ; Epoprostenol ; pharmacology ; In Vitro Techniques ; Indomethacin ; pharmacology ; Male ; Models, Biological ; Muscle Relaxation ; drug effects ; Muscle, Smooth ; drug effects ; physiology ; NG-Nitroarginine Methyl Ester ; pharmacology ; Nitric Oxide ; metabolism ; Penile Erection ; drug effects ; Phenylephrine ; pharmacology ; Plant Extracts ; pharmacology ; Potassium Channel Blockers ; pharmacology ; Potassium Channels ; metabolism ; Pressure ; Rabbits

OBJECTIVETo observe the effect of β₃adrenoceptors (β₃-AR) activation on rat thoracic aorta smooth muscle contractility and the possible related mechanism.

METHODSThe endothelium removed thoracic aorta was pre-contracted with 30 mmol/L KCl physiological saline solution (PSS). Then the tension of the thoracic aorta was recorded in presence of BRL37344 (BRL) to determine the action of β₃-AR. The tension of the thoracic aorta was also recorded in the presence of Propranolol (PRA), SR59230A (SR), L-NNA, H-89 and Iberiotoxin (IBTX) respectively to reveal the underling mechanism of β₃-AR activation on rat vascular smooth muscle. Immunohistochemistry was adopted to confirm the existence and the distribution of β₃-AR in rat thoracic aorta.

RESULTSThe results showed that: (1) The thoracic aorta was relaxed by β₃-AR activation, with a relaxation percentage of (10.59 ± 0.79). (2) β₃-AR was expressed in both endothelial and smooth muscle layer in thoracic aorta sections of rats. (3) PRA did not block the effect of BRL on the thoracic aorta. The relaxation actions of BRL could be antagonized by pre-incubating the thoracic aorta with SR. (4) L-NNA (a NOS inhibitor) and H-89 (a PKA inhibitor) reversed the relaxation effect of BRL on vascular smooth muscle. (5) The effect of BRL was decreased after application of Ibriotoxin (IBTX), a large conductance calcium dependent potassium channel blocker.

CONCLUSIONThe results confirmed that activation of β₃-AR led to relaxation of thoracic aorta smooth muscle. The relaxation action of β₃-AR on smooth muscle of rat thoracic aorta was related to activation of NOS and PKA signaling pathway. Large conductance Ca²⁺-K⁺ channels were involved in the relaxation action of β₃-AR activation on rat thoracic aorta smooth muscle.

Animals ; Aorta, Thoracic ; physiology ; In Vitro Techniques ; Isoquinolines ; Large-Conductance Calcium-Activated Potassium Channels ; physiology ; Muscle Contraction ; Muscle Relaxation ; Muscle, Smooth, Vascular ; physiology ; Nitroarginine ; Peptides ; Propanolamines ; Propranolol ; Rats ; Receptors, Adrenergic, beta-3 ; physiology ; Signal Transduction ; Sulfonamides

OBJECTIVETo examine the relaxant effects of hydro-ethanolic, macerated aqueous (MA) and lipidfree macerated aqueous (LFMA) extract of Tymus vulgaris on tracheal chains of guinea pigs.

METHODSThe relaxant effects of five cumulative concentrations of each extract (0.4, 0.8, 1.2, 1.6 and 2.0 g/100 mL) were compared with saline as negative control and five cumulative concentrations of theophylline (0.1, 0.2, 0.4, 0.6 and 0.8 mmol/L) on precontracted tracheal smooth muscle of guinea pig with 60 mmol/L KCl (group 1) and 10 µmol/L methacholine (group 2, n=6 for each group).

RESULTSIn group 1 all concentrations of theophylline, three higher concentrations of hydro-ethanolic, two concentrations of LFMA and last concentration of MA extracts showed significant relaxant effects compared with that of saline (P<0.05 or P<0.01). Two lower concentrations of LFMA and all concentrations of MA except higher one caused contraction compared with saline (P<0.05 or 0.01). In group 2 experiments, all concentrations of theophylline, hydro-ethanolic, MA and LFMA extracts showed significant relaxant effects compared to that of saline (P<0.05 or P<0.01). In both groups, the relaxant effect of all concentrations of hydro-ethanolic extract were significantly higher than most concentrations of others (P<0.05 or P<0.01). The relaxant effect of different concentrations of three extracts were significantly greater in group 2 compared with group 1 experiments (all P<0.01). There were significantly positive correlations between the relaxant effects and concentrations for theophylline and all extracts in both groups (P<0.05 or P<0.01).

CONCLUSIONHydro-ethanolic extract has a potent weaker relaxant effect for other extracts from Tymus vulgaris on tracheal chains of guinea pigs.

Animals ; Bronchodilator Agents ; pharmacology ; Guinea Pigs ; In Vitro Techniques ; Lamiaceae ; chemistry ; Lipids ; chemistry ; Muscle Relaxation ; drug effects ; Muscle, Smooth ; drug effects ; physiology ; Plant Extracts ; pharmacology ; Solubility ; Solutions ; Theophylline ; Trachea ; physiology ; Water ; chemistry

OBJECTIVETo determine whether matrine, a kind of traditional Chinese medicinal alkaloid, can relax the aortic smooth muscles isolated from guinea pigs and to investigate the mechanism of its relaxant effects.

METHODSPhenylephrine or potassium chloride concentration-dependent relaxation response of aortic smooth muscles to matrine was studied in the precontracted guinea pigs.

RESULTSMatrine (1 x 10(-4) mol/L -3.3 x 10(3) mol/L) relaxed the endothelium-denuded aortic rings pre-contracted sub-maximally with phenylephrine, in a concentration-dependent manner, and its pre-incubation (3.3 x 10(-3) mol/L) produced a significant rightward shift in the phenylephrine dose-response curve, but had no effects on the potassium chloride-induced contraction. The anti-contractile effect of matrine was not reduced by the highly selective ATP-dependent K+ channel blocker glibenclamide (10(-5) mol/L), either by the non-selective K+ channel blocker tetraethylammonium (10(-3) mol/L), or by the beta-antagonist propranolol (10(-5) mol/L). In either "normal" or "Ca(2+)-free" bathing medium, the phenylephrine-induced contraction was attenuated by matrine (3.3 x 10(-3) mol/L), indicating that the vasorelaxation was due to inhibition of intracellular and extracellular Ca2+ mobilization.

CONCLUSIONMatrine inhibits phenylephrine-induced contractions by inhibiting activation of alpha-adrenoceptor and interfering with the release of intracellular Ca2+ and the influx of extracellular Ca2+.

Alkaloids ; chemistry ; pharmacology ; Animals ; Aorta ; drug effects ; physiology ; Calcium ; pharmacology ; Culture Media ; pharmacology ; Dose-Response Relationship, Drug ; Glyburide ; pharmacology ; Guinea Pigs ; In Vitro Techniques ; Male ; Muscle Contraction ; drug effects ; Muscle Relaxation ; drug effects ; Muscle, Smooth, Vascular ; drug effects ; physiology ; Phenylephrine ; pharmacology ; Potassium Chloride ; pharmacology ; Propranolol ; pharmacology ; Quinolizines ; chemistry ; pharmacology ; Tetraethylammonium ; pharmacology

OBJECTIVETo investigate the effect of ascorbic acid (VC) on relaxation of ex vivo Bufo gastrocnemius during sustained isometric contraction.

METHODSDynamic tension of the muscle was recorded under constant voltage stimulation within 7.0 min at 2 s intervals. The rest tension and relaxation rate of the muscle was obtained by weighted fitting to the relaxation process of tension <90% of its peak with a mono-exponential model to characterize the muscular relaxation.

RESULTSVC at 2.0 mmol/L alone or in combination with the inhibitors of the antixoidation enzymes (surperoxide dismutase, glutathione peroxidase and catalase) resulted in negligible alterations in the muscular relaxation kinetics. VC combined with the inhibitor of surperoxide dismutase resulted in significantly lowered relaxation rate while increased rest tension, but VC with the inhibitor of either catalase or glutathione peroxidase showed negligible action. VC combined with the inhibitors of all the 3 enzymes also caused significant effect on the muscular relaxation kinetics, which was similar the effect of VC with superoxide dismutase inhibitor.

CONCLUSIONVC at high concentration may result in oxidative toxicity to the biological system rich in transitional metal ion complexes but with low antioxidation capacity by causing superoxide-mediated oxidative damages.

Animals ; Ascorbic Acid ; pharmacology ; Bufonidae ; Electric Stimulation ; In Vitro Techniques ; Isometric Contraction ; drug effects ; Muscle Relaxation ; drug effects ; Muscle, Skeletal ; drug effects ; physiology