[Show abstract][Hide abstract] ABSTRACT: This study was designed to investigate whether Resveratrol (Res) could be a prophylactic factor in the prevention of I/R injury and to shed light on its underlying mechanism. Primary culture of neonatal rat cardiomyocytes were randomly distributed into three groups: the normal group (cultured cardiomyocytes were in normal conditions), the I/R group (cultured cardiomyocytes were subjected to 2 h simulated ischemia followed by 4 h reperfusion), and the Res+I/R group (100 µmol/L Res was administered before cardiomyocytes were subjected to 2 h simulated ischemia followed by 4 h reperfusion). To test the extent of cardiomyocyte injury, several indices were detected including cell viability, LDH activity, Na(+)-K(+)-ATPase and Ca(2+)-ATPase activity. To test apoptotic cell death, caspase-3 activity and the expression of Bcl-2/Bax were detected. To explore the underlying mechanism, several inhibitors, intracellular calcium, SOD activity and MDA content were used to identify some key molecules involved. Res increased cell viability, Na(+)-K(+)-ATPase and Ca(2+)-ATPase activity, Bcl-2 expression, and SOD level. While LDH activity, capase-3 activity, Bax expression, intracellular calcium and MDA content were decreased by Res. And the effect of Res was blocked completely by either L-NAME (an eNOS inhibitor) or MB (a cGMP inhibitor), and partly by either DS (a PKC inhibitor) or Glybenclamide (a K(ATP) inhibitor). Our results suggest that Res attenuates I/R injury in cardiomyocytes by preventing cell apoptosis, decreasing LDH release and increasing ATPase activity. NO, cGMP, PKC and K(ATP) may play an important role in the protective role of Res. Moreover, Res enhances the capacity of anti-oxygen free radical and alleviates intracellular calcium overload in cardiomyocytes.
[Show abstract][Hide abstract] ABSTRACT: Impairment of pulmonary endothelium function in the pulmonary artery is a direct result of chronic hypoxia. This study is to investigate the vasculoprotective effects of U50,488H (a selective κ-opioid receptor agonist) and its underlying mechanism in hypoxia-induced pulmonary artery endothelial functional injury. Chronic hypoxia was simulated by exposing the rats to 10% oxygen for two weeks. After hypoxia, right ventricular pressure (RVP) and right ventricular hypertrophy index (RVHI) were measured. The pulmonary vascular dysfunction, effect of nitric oxide synthase inhibitor (L-NAME) on the relaxation of U50,488H and level of nitric oxide (NO) were determined. In vitro, the signaling pathway involved in the anti-apoptotic effect of U50,488H was investigated. Cultured endothelial cells were subjected to simulated hypoxia, and cell apoptosis was determined by TUNEL staining. U50,488H (1.25 mg/kg) significantly reduced RVP and RVHI in hypoxia. U50,488H markedly improved both pulmonary endothelial function (maximal vasorelaxation in response to ACh: 74.9±1.8%, n =6, P <0.01 vs. hypoxia for 2 wk group) and increased total NO production (1.65 fold). U50,488H relaxed the pulmonary artery rings of the hypoxic rats. This effect was partly abolished by L-NAME. In cells, U50,488H both increased NO production and reduced hypoxia-induced apoptosis. Moreover, pretreatment with nor-BNI (nor-binaltorphimine, a selective κ-opioid receptor antagonist), PI3K inhibitor, Akt inhibitor or L-NAME almost abolished anti-apoptotic effect exerted by U50,488H. U50,488H resulted in increases in Akt and eNOS phosphorylation. These results demonstrate that pretreatment with U50,488H attenuates hypoxia-induced pulmonary vascular endothelial dysfunction in an Akt-dependent and NO-mediated fashion.
Preview · Article · Nov 2012 · Journal of Applied Physiology
[Show abstract][Hide abstract] ABSTRACT: κ-opioid receptor (κ-OR) activation with U50,488H, a selective κ-OR agonist, has been previously demonstrated to prevent against cardiac arrhythmias via stabilizing the synthesis and degradation of an integral membrane protein, Cx43, in gap junctions. However, the exact prevention mechanism remains unclear. The present study tested the hypothesis that the kappa OR agonist U50,488H mediates the prevention of arrhythmia through the regulation of intracellular calcium leading to the preservation of Cx43 protein. By performing electrocardiogram monitoring and immunoblotting in isolated Langendorff-perfused rat hearts, high concentrations of calcium-perfused rat hearts exhibited increased cardiac arrhythmias. Diminished expression of Cx43 protein was observed. The utilization of a whole-cell patch clamp technique revealed that U50,488H inhibited L-type calcium current in single ventricular myocytes in a dose-dependent manner. These effects were blocked by nor-binaltorphimine, potent and selective κ-OR antagonists. Administration of U50,488H before myocardial ischemia resulted in an attenuated of total arrhythmia scores. The attenuation effect was blocked by nor-binaltorphimine. The attenuation effect was antagonized both by Bay K8644, a L-type calcium channel agonist, and also by the Cx43 uncoupler heptanol. Finally, immunoblotting data demonstrated that the preservation of Cx43 protein conferred by U50,488H was reversed in the presence of Bay K8644. In summary, the present study demonstrates κ-OR activation with U50,488H may confer antiarrhythmic effects via modulation of the calcium-Cx43 pathway.
No preview · Article · Sep 2012 · American journal of therapeutics
[Show abstract][Hide abstract] ABSTRACT: Alcohol intake is associated with myocardial contractile dysfunction and apoptosis although the precise mechanism is unclear. This study was designed to examine the effect of the cytochrome P450 enzyme CYP2E1 inhibition on ethanol-induced cardiac dysfunction. Adult male mice were fed a 4% ethanol liquid or pair-fed control diet for 6weeks. Following 2weeks of diet feeding, a cohort of mice started to receive the CYP2E1 inhibitor diallyl sulfide (100mg/kg/d, i.p.) for the remaining feeding duration. Cardiac function was assessed using echocardiographic and IonOptix systems. Western blot analysis was used to evaluate CYP2E1, heme oxygenase-1 (HO-1), iNOS, the intracellular Ca(2+) regulatory proteins sarco(endo)plasmic reticulum Ca(2+)-ATPase, Na(+)Ca(2+) exchanger and phospholamban, pro-apoptotic protein cleaved caspase-3, Bax, c-Jun-NH(2)-terminal kinase (JNK) and apoptosis signal-regulating kinase (ASK-1). Ethanol led to elevated levels of CYP2E1, iNOS and phospholamban, decreased levels of HO-1 and Na(+)Ca(2+) exchanger, cardiac contractile and intracellular Ca(2+) defects, cardiac fibrosis, overt O(2)(-) production, and apoptosis accompanied with increased phosphorylation of JNK and ASK-1, the effects were significantly attenuated or ablated by diallyl sulfide. Inhibitors of JNK and ASK-1 but not HO-1 inducer or iNOS inhibitor obliterated ethanol-induced cardiomyocyte contractile dysfunction, substantiating a role for JNK and ASK-1 signaling in ethanol-induced myocardial injury. Taken together, these findings suggest that ethanol metabolism through CYP2E1 may contribute to the pathogenesis of alcoholic cardiomyopathy including myocardial contractile dysfunction, oxidative stress and apoptosis, possibly through activation of JNK and ASK-1 signaling.
[Show abstract][Hide abstract] ABSTRACT: Transcription factor RBP-J-mediated Notch signaling has been implicated in several inherited cardiovascular diseases including aortic valve diseases (AVD). But whether Notch signal plays a role in AVD in adults has been unclear. This study aims to test whether the deletion of RBP-J in adult mice would lead to AVD and to investigate the underlying mechanisms. Cre-LoxP-mediated gene deletion was employed to disrupt Notch signal in adult mice. Immunofluorescence and electron microscope observations showed that deletion of RBP-J in adult mice led to early morphological changes of AVD. The size of aortic valve was enlarged. The endothelial homeostasis was perturbed, probably due to the up-regulation of VEGFR2. The endothelial cells exhibited increased proliferation and loose endothelial junctions. The valvular mesenchyme displayed significant fibrosis, consistent with the up-regulation of TGF-β1 and activation of endothelial-mesenchymal transition. We observed melanin-producing cells in aortic valves. The number of melanin-producing cells increased significantly, and their location changed from the mesenchyme to subendothelial layer of valve cusps in RBP-J deficient mice. These results suggest that RBP-J-mediated Notch signaling in aortic valves may be critically involved in valve homeostasis and valve diseases as well. These findings will be helpful for the understanding of the molecular mechanisms of AVD in adults.
[Show abstract][Hide abstract] ABSTRACT: Acute myocardial ischemia induces electrical and chemical uncoupling of gap junctions, which contributes to conduction abnormalities and re-entrant arrhythmias. We tested the hypothesis that structure and function of Connexin43 may vibrate during acute myocardial ischemia and reperfusion and κ-opioid receptor stimulation may stabilize the alteration of Connexin43.
An animal intervention study was conducted with comparison to a control group.
University preclinical research laboratory.
Age-, weight-, and sex-matched Sprague-Dawley rats.
Adult rat hearts were subjected to ischemia or ischemia/reperfusion, which was induced by temporary occlusion of the left main coronary artery. U50488H was given 10 mins before tissue specimens were taken or before ischemia (1.5 mg/kg, intravenous) and nor-BNI was given 15 mins before tissue specimens were taken or before ischemia (2 mg/kg, intravenous). Tissue samples came from left ventricular myocardium of the rat hearts.
Electrocardiogram, immunohistochemistry, immunoblotting, and reverse transcription-polymerase chain reaction were used to measure changes of arrhythmias, protein, and gene expression of Connexin43, respectively. κ-opioid receptor activation with U50 decreased arrhythmia in a model of myocardial ischemia and reperfusion. In normal hearts, immunohistochemical data showed reduced amount and lateralization of Connexin43 induced by κ-opioid receptor activation, whereas immunoblotting data demonstrated no significant changes between control and U50 group. During ischemia, however, Connexin43 protein underwent dephosphorylation and degradation, and Connexin43 mRNA was upregulated. These alterations were significantly attenuated on κ-opioid receptor stimulation. During ischemia and reperfusion, Connexin43 protein underwent dephosphorylation and degradation and recovered slowly during reperfusion. Activation of κ-opioid receptor accelerated recovery of phosphorylated and total Connexin43.
In normal rat hearts, Connexin43 translocates from intercellular junctions to intracellular locations on κ-opioid receptor activation. In rat hearts experiencing acute myocardial ischemia and reperfusion, protein and gene expression of Connexin43 undergo vibration. This phenomenon is stabilized when κ-opioid receptor is activated and by the fact that κ-opioid receptor produces antiarrhythmic effects.
No preview · Article · Sep 2010 · Critical care medicine
[Show abstract][Hide abstract] ABSTRACT: Modulation of intracellular calcium ([Ca(2+)](i)) transient in response to beta-adrenoceptor stimulation in the hearts of hindlimb unweighted (HLU) rats during simulated weightlessness has not been reported. In the present study, we adopted the rat tail suspension for 4 wk to simulate weightlessness. Effects of simulated microgravity on beta-adrenoceptor responsiveness were then studied. Mean arterial blood pressure, left ventricular pressure (LVP), systolic function [maximum positive change in pressure over time (+dP/dt(max))], and diastolic function [maximum negative change in pressure over time (-dP/dt(max))] were monitored during the in vivo experiment. beta-Adrenoceptor density was quantitated by radioactive ligand binding. Single rat ventricular myocyte was obtained by enzymatic dissociation method. +/-dP/dt(max), myocyte contraction, intracellular [Ca(2+)](i) transient, and L-type calcium current in response to beta-adrenoceptor stimulation with isoproterenol were measured. Compared with the control group, no significant changes were found in heart weight, body weight, and mean arterial blood pressure, whereas LVP and +/-dP/dt(max) were significantly reduced. LVP and +/-dP/dt(max) were significantly attenuated in the HLU group in response to isoproterenol administration. In the in vitro study, the beta-adrenoceptor density was unchanged. Effects of isoproterenol on electrically induced single-cell contraction and [Ca(2+)](i) transient in myocytes of ventricles in HLU rats were significantly attenuated. The enhanced L-type Ca(2+) current elicited by isoproterenol in cardiomyocytes was significantly decreased in the HLU group. The above results indicate that impaired function of L-type Ca(2+) current and decreased [Ca(2+)](i) transient cause the depressed responsiveness of the beta-adrenoceptor stimulation, which may be partially responsible for the depression of cardiac function.
No preview · Article · Apr 2010 · Journal of Applied Physiology
[Show abstract][Hide abstract] ABSTRACT: It remains unclear whether U50488H (a selective kappa-opioid receptor agonist) produces anti-apoptotic effect during ischemia and reperfusion (I/R). Therefore, the effect of U50488H on myocardial apoptosis was investigated in the present study.
Rats were subjected to 45min coronary artery occlusion and 180min of reperfusion. U50488H (1.5mg/kg IV) was given prior to occlusion. Nor-Binaltorphimine (nor-BNI) (2mg/kg IV), a selective kappa-opioid receptor antagonist, was given 10min prior to U50488H. Cardiac apoptosis was evaluated by terminal deoxynucleotidyl transferase mediated dUTP-biotin nick end labeling (TUNEL) assay and in situ identification of nuclear DNA fragmentation.
The ultrastructure injury of myocardium, myocardial infarct size, and plasma CK and LDH were reduced significantly with administration of U50488H before I/R, whereas the effects of U50488H were abolished by nor-BNI. DNA fragments were visualized by agarose electrophoresis, and clear DNA ladder formation was observed in myocardial tissue from hearts subjected to I/R. Administration of U50488H before ischemia exerted a significant anti-apoptotic effect as evidenced by markedly weaker DNA ladder formation. TUNEL staining showed U50488H treatment before I/R significantly reduced the percentage of apoptotic cells, which was blocked by 5-HD, a mitochondrial k(ATP) channel blocker. In accordance, U50488H treatment significantly inhibited I/R-induced elevated activities of caspase-3 and caspase-9. U50488H also produced an increase in Bcl-2 and a decrease in Bax protein expression in the I/R heart, and the anti-apoptotic effects of U50488H were all blocked by nor-BNI.
U50488H reduces myocardial necrosis and apoptosis after I/R and activation of kappa-opioid receptor may mediate a role in U50488H-induced myocardial protection.
No preview · Article · Jun 2009 · Archives of medical research
[Show abstract][Hide abstract] ABSTRACT: The aim of the present study was to determine whether U50,488H, a selective kappa-opioid receptor agonist, inhibits the remodeling of the pulmonary artery (PA). In addition, changes in the concentrations of nitric oxide (NO), endothelin (ET) and angiotensin II (AngII) in hypoxic pulmonary hypertensive (HPH) rats were investigated to explore the mechanisms underlying the effects of U50, 488H on HPH. We found that intraperitoneal administration of U50,488H (every other day) during hypoxia depressed mean pulmonary arterial pressure (mPAP) and attenuated right ventricular pressure (RVP) and right ventricular hypertrophy, at the same time it inhibited remodeling of the PA compared with hypoxia for 2 wk. Moreover, U50,488H also inhibited proliferation of the pulmonary arterial smooth muscle cells (PASMCs) induced by hypoxia for 48 h in a dose-dependent manner. Compared with the 2 wk hypoxia group, U50,488H increased the concentration of NO and decreased the production of ET and AngII (P<0.01). In addition, acute intravenous administration of U50,488H after hypoxia for 4 wk decreased mPAP. Our results suggest that effects of anti-remodeling of the PA and anti-proliferation of the PASMC, and regulation of the vasomotor factors in both blood and pulmonary tissues of HPH rats may be critical mechanisms underlying the preventive and therapeutic effects of U50,488H in HPH rats.
No preview · Article · Apr 2009 · Vascular Pharmacology
[Show abstract][Hide abstract] ABSTRACT: The modulation of beta-adrenoceptor signaling in the hearts of hindlimb unweighting (HU) simulated weightlessness rats has not been reported. In the present study, we adopted the rat tail suspension for 4 wk to simulate weightlessness; then the effects of simulated microgravity on beta-adrenoceptor signaling were studied. Mean arterial blood pressure (ABP), left ventricular pressure (LVP), systolic function (+dP/dtmax), and diastolic function (-dP/dtmax) were monitored in the course of the in vivo experiment. Single rat ventricular myocyte was obtained by the enzymatic dissociation method. Hemodynamics, myocyte contraction, and cAMP production in response to beta-adrenoceptor stimulation with isoproterenol or adenylyl cyclase stimulation with forskolin were measured, and Gs protein was also determined. Compared with the control group, no significant changes were found in heart weight, body weight and ABP, while LVP and +/-dP/dtmax were significantly reduced. The ABP decrease, LVP increase, and +/-dP/dtmax in response to isoproterenol administration were significantly attenuated in the HU group. The effects of isoproterenol on electrically induced single-cell contraction and cAMP production in myocytes of ventricles in the HU rats were significantly attenuated. The biologically active isoform, Gsalpha (45 kDa) in the heart, was unchanged. Both the increased electrically induced contraction and cAMP production in response to forskolin were also significantly attenuated in the simulated weightlessness rats. Above results indicated that impaired function of adenylyl cyclase causes beta-adrenoceptor desensitization, which may be partly responsible for the depression of cardiac function.
No preview · Article · Jun 2008 · Journal of Applied Physiology
[Show abstract][Hide abstract] ABSTRACT: Multiple sclerosis (MS) is a chronic disease characterized by loss of myelin. However, data indicate that autoimmune cells could directly impair neuronal cell bodies and myelin sheath is lacking. The aim of the present study was to determine morphological evidence of the direct impairment of neurons by autoreactive lymphocytes and to further identify the subtypes of these lymphocytes.
Lymphocytes activated by myelin basic protein (MBP) 83-99 and neurons of human brain were co-cultured for 24 h.
Observations through scanning electron microscope showed that MBP-specific lymphocytes (CD4+, CD8+ cells, and NK cells) aggregated in the vicinity of the neuronal cell bodies and the myelin sheaths and attacked them directly, resulting in the degeneration of both neurons.
Our studies provide morphological evidences of the direct impairment of neuronal cell bodies and myelin sheaths by MBP-specific lymphocytes. Our studies also suggest that MBP-specific CD4+, CD8+, and NK cells might be involved in this process. These processes may play a role in the direct impairment of neurons and myelin sheaths in early stages of MS and provide evidences for the application of immunosuppressant therapy of MS.
No preview · Article · Feb 2008 · Archives of Medical Research
[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to investigate the protective effect of U50,488H, a selective kappa-opioid receptor agonist, in the ischemia/reperfusion (I/R) rat and to delineate the underlying mechanism. Rat heart I/R injury was induced by occluding the left anterior descending coronary artery for 45 min and restoring perfusion for 120 min. U50,488H or vehicle was intravenously injected before ischemia. Electrocardiogram, heart rate (HR), arterial blood pressure (ABP), left ventricular pressure (LVP), systolic function (+dp/dtmax), and diastolic function (-dp/dtmax) were monitored in the course of the experiment. Myocardial infarction size was evaluated. Plasma concentrations of cardiac troponin T (cTnT), creatine kinase (CK), and lactate dehydrogenase (LDH) were measured. Single rat ventricular myocyte was obtained by enzymatic dissociation method. The potassium currents (IK) of isolated ventricular myocytes were recorded with the whole-cell configuration of the patch-clamp technique. Compared with the sham control group, no significant change was found in HR, while ABP, LVP and +/-dp/dtmax were significantly reduced in the I/R group. Administration of U50,488H significantly lowered HR in both control and I/R groups. Compared with the vehicle-treated I/R group, administration of U50,488H had no significant effect on I/R-induced reduction in ABP, LVP, and +/-dp/dtmax. However, this treatment significantly reduced the myocardial infarction size, and markedly decreased the contents of plasma cTnT, CK and LDH. During ischemia and reperfusion, the incidence of ventricular arrhythmia in U50,488H-treated rats was significantly reduced. These effects were independent of the bradycardia induced by U50,488H, as the reducing infarct size and antiarrhythmic effect of U50,488H were still observed in animals in which heart rate was kept constant by electrical pacing. U50,488H and BRL-52537 still produced an antiarrhythmic effect when the rat heart was subjected to a shorter ischemic period of 10 min occlusion of coronary artery, which produced no infarction. IK of the myocytes were inhibited by U50,488H in a dose-dependent manner in normal and hypoxic rat ventricular myocytes. However, the effects of U50,488H on IK did not show any significant difference in normal and hypoxic myocytes. The above-described effects of U50,488H were totally blocked by nor-Binaltorphimine, a selective kappa-opioid receptor antagonist. The results suggest that kappa-opioid agonist U50,488H exerts its direct cardioprotective and antiarrhythmic effects against I/R via kappa-opioid receptor, which participates in the regulation of potassium channels in normal and hypoxic ventricular myocytes.
No preview · Article · Oct 2007 · Heart and Vessels
[Show abstract][Hide abstract] ABSTRACT: In this study, we determined the effect of U50,488H (a selective kappa-opioid receptor agonist) on pulmonary artery in rats and investigated its prevention and treatment effects on hypoxic pulmonary hypertension (HPH). Isolated pulmonary arterial rings were superfused and the tension of the vessel was measured. The model of HPH was developed and indexes for hemodynamics and right ventricular hypertrophy were measured. We found that U50,488H relaxed the pulmonary artery rings in a dose-dependent manner and the effect was abolished by nor-binaltorphimine, a selective kappa-opioid receptor antagonist. Intravenous administration of U50,488H significantly lowered mean pulmonary artery pressure (mPAP) in normal rats and this effect was also abolished by nor-binaltorphimine. Hypoxia induced severe HPH in rats and intraperitoneal administration of U50,488H (every other day) during chronic hypoxia reduced mPAP and attenuated right ventricular hypertrophy compared with the control group. Moreover, acute intravenous administration of U50,488H after the rats subjected to chronic hypoxia for 4 weeks significantly lowered mPAP. Thus, U50,488H has significant vasorelaxant effect in rat pulmonary artery and has certain preventive and therapeutic application in HPH.
No preview · Article · May 2006 · Journal of Cardiovascular Pharmacology
[Show abstract][Hide abstract] ABSTRACT: To investigate the relaxation effect and underlying mechanism of U50,488H (a selective kappa-opioid receptor agonist) in pulmonary artery in the rat.
Isolated pulmonary artery ring was perfused and the tension of the vessel was measured.
U50,488H relaxed the pulmonary artery ring in a dose-dependent manner and the effect was abolished by nor-binaltorphimine, a selective kappa-opioid receptor antagonist. The relaxation effect of U50,488H in pulmonary artery was partially endothelium-dependent and was significantly attenuated in the presence of L-NAME. The relaxation effect of U50,488H was significantly attenuated by K(V) channel blocker 4-AP (4-aminopyridine), but not by glibenclamide (ATP-sensitive K+ channel blocker) nor TEA (tetraethylamonium, Ca2+-activated K+ channel blocker). Further study also showed that endothelium denudation and 4-AP have an additive inhibitory effect on pulmonary artery relaxation caused by U50,488H.
Kappa-opioid receptor activation by U50,488H relaxes pulmonary artery via two separate pathways: one is endothelium-derived nitric oxide, the other is K(V) channel in pulmonary artery smooth muscle.
[Show abstract][Hide abstract] ABSTRACT: To explore the changes and relationship between serum soluble P-selectin, tumor necrosis factor-alpha (TNF-alpha) in coronary heart disease patients with acute coronary syndrome (ACS) and human cytomegalovirus (HCMV) infection.
The levels of circulating soluble P-selectin, TNF-alpha, HCMV-IgM and HCMV-IgG were determined by enzyme-linked immunosorbent assay (ELISA) in 79 cases for ACS group, 30 cases for stable angina (SA) group and 30 healthy control cases.
(1) The serum positive rate of HCMV-IgM and HCMV-IgG in the ACS, SA and healthy control groups were 30.4% (24/79), 10.0% (3/30) and 6.7% (2/30); 86.1% (68/79), 80.0% (24/30) and 53.3% (16/30), respectively. Positive rate of HCMV-IgM in the ACS was higher than those in SA and healthy control groups (P < 0.01), positive rate of HCMV-IgG in the ACS and SA groups were higher than that of the healthy control group (P < 0.01). (2) Compared with the SA group and healthy control group, the levels of the serum soluble P-selectin and TNF-alpha were significantly higher in patients with ACS [(6437.3 +/- 666.9) pg/ml vs. (1520.0 +/- 112.7) pg/ml and (1481.0 +/- 109.1) pg/ml, (56.2 +/- 18.4) pg/ml vs. (27.3 +/- 13.7) pg/ml and (28.1 +/- 11.3) pg/ml], respectively, P < 0.01). The AMI group, compared with the UA group in the ACS group, had significantly higher levels of the serum soluble P-selectin and TNF-alpha (P < 0.01). Compared with the SA group, the levels of the serum soluble P-selectin and TNF-alpha were not significantly different in healthy control group. (3) The levels of the serum soluble P-selectin and TNF-alpha in HCMV-IgM positive patients were significantly higher than the HCMV-IgM negative patients in the ACS group (P < 0.01).
The chronic infection with HCMV might injure endothelial cells that subsequently contribute to the formation and progression of atherosclerosis, the acute infection with HCMV may induce increased serum levels of soluble P-selectin and TNF-alpha that might participate in acute coronary events.
No preview · Article · Jun 2005 · Zhonghua shi yan he lin chuang bing du xue za zhi = Zhonghua shiyan he linchuang bingduxue zazhi = Chinese journal of experimental and clinical virology
[Show abstract][Hide abstract] ABSTRACT: The purpose of this study was to investigate the effects of vasonatrin peptide (VNP) on electrically-induced intracellular calcium ([Ca(2+)](i)) transient and mechanism of the effects in the cardiac myocytes. The [Ca(2+)](i) transient was measured with a fluoremetric method. The effects of HS-142-1, 8-Br-cGMP and methylene blue (MB) on [Ca(2+)](i) transient in cardiac myocytes were also determined. Isoproterenol (Iso) at 10(-10)~10(-6) mol/L augmented electrically-induced [Ca(2+)](i) transient dose-dependently, which was (13+/-8)% (P>0.05), (26+/-13)% (P< 0.05), (66+/-10)% (P<0.01), (150+/-10)% (P<0.01) and (300+/-25)% (P<0.01), respectively. These effects were blocked by an beta-adrenergic bloker propranolol (10(-6) mol/L). The effect of Iso (10(-8) mol/L) on [Ca(2+)](i) transient was attenuated in a dose-dependent manner by VNP at 10(-10)~10(-6) mol/L, which was (99+/-3)% (P>0.05), (96+/-2)% (P<0.05), (84+/-6)% (P<0.01), (66+/-3)% (P<0.01) and (62+/-3)% (P<0.01), respectively. 8-Br-cGMP (10(-7)~10(-3) mol/L) aslo attenuated 10(-8) mol/L Iso-induced [Ca(2+)](i) transient dose-dependent. The effect of VNP on [Ca(2+)](i) transient was almost abolished in the presence of HS-142-1 (2x10(-5) mol/L), an antagonist of the natriuretic peptide guanylate cyclase (GC) receptors. MB (10(-5) mol/L), an inhibitor of GC, not only blocked the effect of VNP in myocytes, but also augmented electrically-induced [Ca(2+)](i) transient. VNP and HS-142-1 themselves did not change the [Ca(2+)](i) transient in the cardiac myocytes significantly. But MB augmented the [Ca(2+)](i) transient in the cardiac myocytes significantly. These results suggest that VNP attenuates [Ca(2+)](i) transient induced by Iso. This effect is possibly achieved by binding VNP with the natriuretic peptide GC receptors in the myocytes, leading to an increase in intracellular cGMP.
No preview · Article · Jun 2004 · Sheng li xue bao: [Acta physiologica Sinica]
[Show abstract][Hide abstract] ABSTRACT: To investigate the regulatory effects of vasonatrin peptide (VNP) on the expression of C-type natriuretic peptide receptor (NPR-C) in cultured neonatal rat cardiac myocytes and fibroblasts.
Quantitative RT-PCR was undertaken to evaluate the levels of NPR-C mRNA and radioimmunoassay was used to determine the formation of intracellular cGMP.
Twenty-four hours hypoxic exposure increased the level of NPR-C mRNA in cardiomyocytes, while did not alter the expression of NPR-C in cardiac fibroblasts. VNP (10(-8)-10(-6) mol/L) reduced the levels of NPR-C mRNA in cardiac myocytes induced by hypoxia in a concentration-dependent manner, and with high concentration (10(-6) mol/L) also decreased the expression of NPR-C in cardiac fibroblasts and air-control cardiac myocytes. The inhibitory effects of VNP on the expression of NPR-C was mimicked by 8-bromo-cGMP 10(-6) mol/L (a membrane permeable analog of cGMP). VNP (10(-8)-10(-6) mol/L) increased the formation of intracellular guanosine-3',5'-cyclic monophosphate (cGMP) in both cardiac myocytes and fibroblasts. HS-142-1, the particulate guanylyl cyclase-coupled receptor antagonist, partially abrogated the above effects of VNP.
Hypoxic exposure for 24 h up-regulated the expression of NPR-C in cultured neonatal rat cardiac myocytes. VNP decreased the expression of NPR-C in cardiac myocytes and fibroblasts under both air-control and hypoxic condition, which was at least partially mediated by guanylate cyclase linked natriuretic peptide receptors through increasing the intracellular cGMP.
Preview · Article · May 2004 · Acta Pharmacologica Sinica
[Show abstract][Hide abstract] ABSTRACT: The purpose of this study was to investigate the vasorelaxing effect of vasonatrin peptide (VNP) on human intramammary artery (HIMA).The vasorelaxing effect of VNP on HIMA was measured by means of perfusion in vitro. The effects of HS-142-1, TEA, 8-Br-cGMP and methylene blue (MB) were also observed. It was found that VNP caused a concentration-dependent relaxation in HIMA which was independent of the endothelium. 8-Br-cGMP (0.1-1000 micromol/L) also caused a concentration-dependent relaxation in HIMA. The vasorelaxing effect of VNP disappeared in the presence of HS-142-1 (20 micromol/L), an antagonist of the natriuretic peptide guanylate cyclase (GC) receptor. MB (10 micromol/L), an inhibitor of GC, not only blocked completely the relaxation of HIMA, but also enhanced the vascular contraction induced by norepinephrine. TEA (1 mmol/L), an antagonist of calcium activated potassium channels (K(Ca)), reduced but not completely blocked the vasorelaxing effect of VNP. These findings suggest that VNP can relax HIMA, which is independent of the endothelium. This effect is possibly achieved by the binding of VNP with the natriuretic peptide GC receptors in the smooth muscle cells (SMCs), leading to an increase in intracellular cGMP level. Moreover, the vasorelaxing effect of VNP is associated with K(Ca).
No preview · Article · Apr 2003 · Sheng li xue bao: [Acta physiologica Sinica]
[Show abstract][Hide abstract] ABSTRACT: The present work was to investigate the effects of vasonatrin peptide (VNP) on cardiomyocyte protein synthesis induced by moderate hypoxia. In cultured neonatal rat cardiomyocytes, MTT methods, total protein measurement and (3)H-leucine incorporation were used to calculate the cell number and measure the protein synthesis of cardiomyocytes. Furthermore, radioimmunoassay was undertaken to observe the effects of VNP on the intracellular levels of cAMP, cGMP and the concentration of endothelin (ET) in the culture medium. The results showed that both the cell number and protein synthesis decreased with severe hypoxia for 24 h. In contrast, under moderate hypoxia, cardiomyocyte hypertrophy developed; the protein synthesis as evidenced by total protein content and 3H-eucine incorporation increased significantly. VNP reduced cardiomyocyte protein synthesis induced by moderate hypoxia in a dose-dependent manner. Furthermore, VNP increased the intracellular level of cGMP and decreased the concentration of ET in the culture medium under moderate hypoxia, but had no effect on the level of cAMP. These results suggest that VNP inhibits moderate hypoxia-induced protein synthesis in cultured neonatal rat cardiac myocytes. This effect is mediated, at least in part, by an increase in intracellular cGMP, a reduction in synthesis, and/or a release in ET of cardiomyocytes.
No preview · Article · Mar 2002 · Sheng li xue bao: [Acta physiologica Sinica]