Inhibition of CYP2E1 attenuates chronic alcohol intake-induced myocardial contractile dysfunction and apoptosis.

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.

Endogenous κ-opioid peptide mediates the cardioprotection induced by ischemic postconditioning.

The aim of this study was to investigate the underlying mechanism that dynorphin, an endogenous kappa opioid receptor (κ-OR) agonist, triggers antiapoptotic effect of postconditioning (Postcon). In addition to vehicle treatment, Sprague Dawley rats (n = 6) underwent a 30-minute left anterior descending occlusion followed by 2 hours of reperfusion with or without a Postcon stimulus. The selective κ-OR antagonist nor-binaltorphimine (Nor-BNI) was administered intravenously 5 minutes before reperfusion. Infarct size was determined by using 2,3,5-triphenyltetrazolium chloride staining. Blood plasma concentrations of creatine kinase (CK) and lactate dehydrogenase (LDH) and myocardial caspase-3 activity were analyzed spectrophotometrically. Myocardial apoptosis was analyzed by the detection of terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick-end labeling. Immunoreactive dynorphin in blood serum and myocardium was measured by means of an antigen-competitive enzyme-linked immunosorbent assay. Infarction size, caspase-3 activity, apoptotic index, and CK and LDH levels were significantly higher in the ischemic/reperfusion group than in the vehicle group (P < 0.01). Postcon significantly reduced infarction size, caspase-3 activity, apoptotic index, CK and LDH levels (P < 0.01 vs. ischemic/reperfusion). Dynorphin content significantly increased after Postcon (P < 0.01). All the effects described above were abolished by Nor-BNI, with the exception of dynorphin content. We found that cardiac protection and antiapoptotic effect of Postcon is mediated by the activation of κ-OR. Effect of Postcon is mediated, at least partially, by enhanced dynorphin expression.

Mechanisms involved in the hypotensive effect of a kappa-opioid receptor agonist in hypertensive rats.

BACKGROUND: It remains unclear whether the activation of kappa-opioid receptors has strong hypotensive effects under hypertensive condition, and the underlying mechanisms have not yet been investigated. Therefore, the present study is designed to use spontaneously hypertensive rats (SHR) to investigate the effects of a kappa-opioid receptor agonist on the regulation of urinary formation in hypertensive conditions and to identify its underlying mechanism. METHODS: The hemodynamics, urine flow rate, vasodilatation of isolated renal artery, and plasma hormones were determined by physiological in vivo experimental technique, isolated artery perfusion technique and radioimmunoassay. RESULTS: Intravenous administration of U50, 448H significantly decreased mean arterial blood pressure in both Wistar-Kyoto (WKY) rats and SHR. However, the blood pressure vasodepressor effect of U50, 448H was much more profound in SHR than in WKY rats. Administration of U50, 448H in SHR not only caused significantly greater effects in increasing urine volume and decreasing plasma anti-diuretic hormone than in WKY rats, but also caused significant reduction in plasma angiotensin. Moreover, vasodilatory effect of U50, 488H was significantly exhibited in the renal artery segments isolated from SHR. All effects described above were abolished by nor-binaltorphimine. CONCLUSIONS: These data indicate that the depressor effect of U50, 488H in SHR is significantly stronger than that in WKY rats, and the effect is mediated or modulated by a kappa-opioid receptor sensitive mechanism. The sensitized hypotensive effect of U50, 488H in SHR may be attributed, in part, to its vasodilatory effect, enhanced beneficial effect on plasma humoral factors, and stronger diuretic effect in these hypertensive animals.

G-T haplotype established by rs3785889-rs16941382 in GOSR2 gene is associated with coronary artery disease in Chinese Han population.

OBJECTIVES: The aim of the present study is to assess the association between the human GOSR2 gene and coronary artery disease using a haplotype-based case-control study in Chinese Han population. METHODS: A total of 283 coronary artery disease patients and 280 controls were genotyped for the human GOSR2 gene (rs197932, rs3785889, rs197922, rs17608766, and rs16941382). Data were analyzed for three separate groups: the total subjects, men, and women. RESULTS: For the total subjects, the frequency of the G-T haplotype established by rs3785889-rs16941382 was significantly higher in the coronary artery disease patients as compared to the control subjects (P=0.009). Multiple logistic regression analysis also confirmed that the subjects with G-T haplotype established by rs3785889-rs16941382 (homozygote) were found having significantly higher chance suffering from coronary artery disease than the ones without this haplotype (OR=1.887, P=0.007). CONCLUSIONS: The G-T haplotype established by rs3785889-rs16941382 may be a risk genetic marker for coronary artery disease patients in Chinese Han population.

[Vasonatrin peptide attenuates the enhancement of electrically-induced intracellular calcium transient by isoproterenol in rat cardiac myocytes].

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.

Ca+2/calmodulin-dependent protein kinase mediates glucose toxicity-induced cardiomyocyte contractile dysfunction.

(1) Hyperglycemia leads to cytotoxicity in the heart. Although several theories are postulated for glucose toxicity-induced cardiomyocyte dysfunction, the precise mechanism still remains unclear. (2) This study was designed to evaluate the impact of elevated extracellular Ca(2+) on glucose toxicity-induced cardiac contractile and intracellular Ca(2+) anomalies as well as the mechanism(s) involved with a focus on Ca(2+)/calmodulin (CaM)-dependent kinase. Isolated adult rat cardiomyocytes were maintained in normal (NG, 5.5 mM) or high glucose (HG, 25.5 mM) media for 6-12 hours. Contractile indices were measured including peak shortening (PS), maximal velocity of shortening/relengthening (±dL/dt), time-to-PS (TPS), and time-to-90% relengthening (TR(90)). (3) Cardiomyocytes maintained with HG displayed abnormal mechanical function including reduced PS, ±dL/dt, and prolonged TPS, TR(90) and intracellular Ca(2+) clearance. Expression of intracellular Ca(2+) regulatory proteins including SERCA2a, phospholamban and Na(+)-Ca(2+) exchanger were unaffected whereas SERCA activity was inhibited by HG. Interestingly, the HG-induced mechanical anomalies were abolished by elevated extracellular Ca(2+) (from 1.0 to 2.7 mM). Interestingly, the high extracellular Ca(2+)-induced beneficial effect against HG was abolished by the CaM kinase inhibitor KN93. (4) These data suggest that elevated extracellular Ca(2+) protects against glucose toxicity-induced cardiomyocyte contractile defects through a mechanism associated with CaM kinase.

[Changes of serum soluble P-selectin and tumor necrotic factor-alpha in patients with CMV induced acute coronary syndrome].

OBJECTIVE: 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. METHODS: 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. RESULTS: (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). CONCLUSION: 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.