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Juntaro Deyama,
Takamitsu Nakamura,
Isao Takishima,
Daisuke Fujioka,
Ken-Ichi Kawabata, Jun-Ei Obata,
Kazuhiro Watanabe,
Yosuke Watanabe,
Yukio Saito,
Hideto Mishina,
Kiyotaka Kugiyama
[show abstract]
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ABSTRACT: Background: Contrast-enhanced ultrasound (CEUS) in the carotid artery has potential as a technique for imaging plaque neovascularization. This study examined whether CEUS could provide information on the severity and instability of coronary artery disease (CAD). Methods and Results: A total of 304 patients with CAD and carotid plaque underwent CEUS examination of the carotid artery. Intraplaque neovascularization was identified on the basis of microbubbles within the plaque and graded as: G0, not visible; G1, moderate; or G2, extensive microbubbles. The complexity and extent of the coronary lesions were assessed angiographically. A higher grade of CEUS-assessed plaque neovascularization of the carotid artery was associated significantly with greater complexity (ρ=0.48 by Spearman's rank correlation test) and extent (ρ=0.51) of coronary lesions. G2 plaque neovascularization was a risk for acute coronary syndrome, independent of traditional risk factors (odds ratio 1.91, 95% confidence interval 1.04-3.53, P<0.01). Subgroup analysis showed that carotid CEUS-assessed neovascularization regressed in 12 (46%) of 26 plaques in patients during 6 months of statin treatment, whereas regression occurred in 2 (14%) of 14 plaques in patients not taking a statin (P=0.04, Chi-square test). Conclusions: CEUS examination of the carotid artery may provide valuable information on the severity and instability of CAD and also the efficacy of antiatherosclerotic treatment.
Circulation Journal 03/2013; · 3.77 Impact Factor
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ABSTRACT: AIMS: Chronic depletion of myocardial glutathione (GSH) may play a role in cardiac remodeling and dysfunction. This study examined the relationship between chronic GSH depletion and cardiac failure induced by pressure overload in mice lacking the modifier subunit (GCLM) of glutamate-cysteine ligase, the rate-limiting enzyme for GSH synthesis. In addition, we examined the association between idiopathic dilated cardiomyopathy (DCM) in humans and -588C/T polymorphism of GCLM gene, which reduces plasma levels of GSH.Methods and ResultsPressure overload in mice was created by transverse aortic constriction (TAC). Myocardial GSH levels after TAC in GCLM(-/-) mice were 31% of those in GCLM(+/+) mice. TAC resulted in greater heart and lung weight-to-body weight ratios, greater dilation and dysfunction of left ventricle, more extensive myocardial fibrosis and worse survival in GCLM(-/-) than GCLM(+/+) mice. Supplementation of GSH diethyl ester reversed the left ventricular dilation and contractile dysfunction and the increased myocardial fibrosis after TAC in GCLM(-/-) mice. The prevalence of -588T polymorphism of the GCLM gene was significantly higher in DCM patients (n=205) than in age- and sex-matched control subjects (n=253) (36% vs. 19%, respectively, P < 0.001). The -588T polymorphism increased the risk of DCM that was independent of age, diabetes and systolic blood pressure (OR 3.13, 95% CI 2.28 to 4.44; P < 0.0001). CONCLUSIONS: Chronic depletion of GSH exacerbates remodeling and dysfunction in the pressure overloaded heart. The clinical relevance of this mouse model is supported by a significant association between -588T polymorphism of GCLM gene and patients with DCM.
Cardiovascular research 11/2012; · 5.80 Impact Factor
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ABSTRACT: It remains undetermined whether the addition of ezetimibe to ongoing statin therapy is more effective than increasing the dose of statin for reducing remnant lipoprotein levels in patients with remnant lipoproteinemia on previous statin treatment. This study examined whether combined ezetimibe and statin therapy resulted in a greater improvement in remnant lipoprotein levels and endothelial function than with the dose of statin in patients with remnant lipoproteinemia on previous statin treatment.
A total of 63 patients with stable coronary artery disease and high levels of remnant-like lipoprotein particle cholesterol (RLP-C) (≥5.0 mg/dL) on statin treatment were assigned randomly to two groups and treated with either addition of ezetimibe (10mg/day, n=32) or doubling of statin dose (n=31). The lipid profiles and flow-mediated dilation (FMD) of the brachial artery were measured at enrollment and after 6 months of treatment. Statin and ezetimibe combined therapy reduced RLP-C and improved FMD to a greater extent than doubling the statin dose (% reduction in RLP-C, 48 ± 18% vs. 33 ± 24%, respectively, p=0.01; % improvement in FMD, 47 ± 48% vs. 24 ± 23%, respectively, p=0.02).
The addition of ezetimibe to ongoing statin treatment reduced RLP-C levels and improved endothelial dysfunction to a greater extent than doubling the statin dose in patients with high RLP-C levels on previous statin treatment. The present results are preliminary and should be confirmed by further studies on a larger number of study patients.
Journal of Cardiology 03/2012; 60(1):12-7. · 1.28 Impact Factor
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Yukio Saito,
Kazuhiro Watanabe,
Daisuke Fujioka,
Takamitsu Nakamura, Jun-ei Obata,
Kenichi Kawabata,
Yosuke Watanabe,
Hideto Mishina,
Shun Tamaru,
Yoshihiro Kita,
Takao Shimizu,
Kiyotaka Kugiyama
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ABSTRACT: Group IVA cytosolic phospholipase A(2) (cPLA(2)α), which preferentially cleaves arachidonic acid from phospholipids, plays a role in apoptosis and tissue injury. Downstream signals in response to tumor necrosis factor (TNF)-α, a mediator of myocardial ischemia-reperfusion (I/R) injury, involve cPLA(2)α activation. This study examined the potential role of cPLA(2)α and its mechanistic link with TNF-α in myocardial I/R injury using cPLA(2)α knockout (cPLA(2)α(-/-)) mice. Myocardial I/R was created with 10-wk-old male mice by 1 h ligation of the left anterior descending coronary artery, followed by 24 h of reperfusion. As a result, compared with wild-type (cPLA(2)α(+/+)) mice, cPLA(2)α(-/-) mice had a 47% decrease in myocardial infarct size, preservation of echocardiographic left ventricle (LV) function (%fractional shortening: 14 vs. 21%, respectively), and lower content of leukotriene B(4) and thromboxane B(2) (62 and 50% lower, respectively) in the ischemic myocardium after I/R. Treatment with the TNF-α inhibitor (soluble TNF receptor II/IgG1 Fc fusion protein, sTNFR:Fc) decreased myocardial I/R injury and LV dysfunction in cPLA(2)α(+/+) mice but not cPLA(2)α(-/-) mice. sTNFR:Fc also suppressed cPLA(2)α phosphorylation in the ischemic myocardium after I/R of cPLA(2)α(+/+) mice. Similarly, sTNFR:Fc exerted protective effects against hypoxia-reoxygenation (H/R)-induced injury in the cultured cardiomyocytes from cPLA(2)α(+/+) mice but not cPLA(2)α(-/-) cardiomyocytes. H/R and TNF-α induced cPLA(2)α phosphorylation in cPLA(2)α(+/+) cardiomyocytes, which was reversible by sTNFR:Fc. In cPLA(2)α(-/-) cardiomyocytes, TNF-α induced apoptosis and release of arachidonic acid to a lesser extent than in cPLA(2)α(+/+) cardiomyocytes. In conclusion, disruption of cPLA(2)α attenuates myocardial I/R injury partly through inhibition of TNF-α-mediated pathways.
AJP Heart and Circulatory Physiology 03/2012; 302(10):H2018-30. · 3.71 Impact Factor
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Takamitsu Nakamura,
Yoshinobu Kitta,
Manabu Uematsu,
Wataru Sugamata,
Mitsumasa Hirano,
Daisuke Fujioka,
Keita Sano,
Yukio Saito,
Ken-Ichi Kawabata, Jun-Ei Obata,
Kiyotaka Kugiyama
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ABSTRACT: BACKGROUND: Single assessment of either flow-mediated vasodilatation of the brachial artery (FMD) or carotid plaque echolucency provides prognostic information for both cerebrovascular and coronary events. OBJECTIVES: This study tested the hypothesis that combined assessment using carotid plaque echolucency and FMD may have an additive effect when predicting cardiovascular events in patients with coronary artery disease (CAD). METHODS: Ultrasound assessment of carotid plaque echolucency with integrated backscatter (IBS) analysis (calibrated IBS=intima-media IBS value-adventitia IBS) and FMD was performed in 547 consecutive patients with CAD. All the study patients were followed up prospectively for a period of ≤60months until the occurrence of one of the following cardiovascular events: cardiac death, non-fatal myocardial infarction, unstable angina requiring coronary revascularization, or ischemic stroke. RESULTS: During a mean follow-up period of 52±10months, 69 cardiovascular events occurred. A multivariate Cox proportional hazard model after 1000 bootstrapped resampling demonstrated that calibrated IBS and FMD were significant, independent predictors of future cardiovascular events after adjustment for known risk factors (calibrated IBS, HR 0.88, 95% CI 0.83-0.93; FMD, HR 0.76, 95% CI 0.68-0.85). The c-statistics, net reclassification improvement (NRI), and integrated discrimination improvement (IDI) analyses showed that the combination of calibrated IBS and FMD values had a greater incremental effect on the predictive value of known risk factors for cardiovascular events. CONCLUSIONS: Combined assessment of brachial endothelial function and carotid plaque echolucency is an independent predictor of cardiovascular events and improves risk prediction when added to known risks.
International journal of cardiology 02/2012; · 7.08 Impact Factor
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Kazuhiro Watanabe,
Daisuke Fujioka,
Yukio Saito,
Takamitsu Nakamura, Jun-ei Obata,
Kenichi Kawabata,
Yosuke Watanabe,
Hideto Mishina,
Shun Tamaru,
Kohji Hanasaki,
Kiyotaka Kugiyama
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ABSTRACT: Group X secretory PLA(2) (sPLA(2)-X) is expressed in neutrophils and plays a role in the pathogenesis of neutrophil-mediated tissue inflammation and injury. This study tested the hypothesis that sPLA(2)-X in neutrophils may contribute to the pathogenesis of abdominal aortic aneurysms (AAA) using sPLA(2)-X(-/-) mice. AAA was created by application of CaCl(2) to external surface of aorta. As a result, the aortas of sPLA(2)-X(-/-) mice had smaller diameters (percent increase from baseline; 24.8 ± 3.5% vs. 49.9 ± 9.1%, respectively; P < 0.01), a reduced grade of elastin degradation, and lower activities of elastase and gelatinase (26% and 19% lower, respectively) after CaCl(2) treatment compared with sPLA(2)-X(+/+) mice. In sPLA(2)-X(+/+) mice, immunofluorescence microscopic images showed that the immunoreactivity of sPLA(2)-X was detected only in neutrophils within aortic walls 3 days, 1, 2, and 6 wk after CaCl(2) treatment, whereas the immunoreactivity was not detected in macrophages or mast cells in aortic walls. sPLA(2)-X immunoreactivity also was colocalized in cells expressing matrix metalloproteinase (MMP)-9. Neutrophils isolated from sPLA(2)-X(-/-) mice had lower activities of elastase, gelatinase, and MMP-9 in response to stimuli compared with sPLA(2)-X(+/+) mice. The attenuated release of elastase and gelatinase from sPLA(2)-X(-/-) neutrophils was reversed by exogenous addition of mouse sPLA(2)-X protein. The adoptive transfer of sPLA(2)-X(+/+) neutrophils days 0 and 3 after CaCl(2) treatment reversed aortic diameters and elastin degradation grades in the lethally irradiated sPLA(2)-X(+/+) mice reconstituted with sPLA(2)-X(-/-) bone marrow to an extent similar to that seen in sPLA(2)-X(+/+) mice. In conclusion, sPLA(2)-X in neutrophils plays a pathogenic role in AAA in a mice model.
AJP Heart and Circulatory Physiology 01/2012; 302(1):H95-104. · 3.71 Impact Factor
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Takamitsu Nakamura, Jun-ei Obata,
Mitsumasa Hirano,
Yoshinobu Kitta,
Daisuke Fujioka,
Yukio Saito,
Ken-ichi Kawabata,
Kazuhiro Watanabe,
Yosuke Watanabe,
Hideto Mishina,
Kiyotaka Kugiyama
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ABSTRACT: Triglycerides-rich lipoproteins are related to residual cardiovascular risk in patients on lipid-lowering treatment who achieve low-density lipoprotein cholesterol (LDL-C) goals. This study examined the predictive value of remnant lipoprotein levels for cardiovascular events in patients with coronary artery disease (CAD) with LDL-C levels <100mg/dL on lipid-lowering therapy.
Serum levels of remnant lipoproteins (remnant-like lipoprotein particles cholesterol; RLP-C) were measured by an immunoseparation method in 560 patients with CAD who had LDL-C levels <100mg/dL on lipid-lowering therapy, including statin (58%), fibrate (13%) or diet only (29%). All the patients were followed prospectively for a period of ≤ 36 months or until occurrence of one of the following events: cardiac death, non fatal myocardial infarction, unstable angina requiring coronary revascularization, or ischemic stroke.
During a mean follow-up period of 33 months, 40 events occurred. Stepwise multivariate Cox proportional hazard analysis showed that RLP-C was a significant predictor of cardiovascular events after adjustment for known risk factors and lipid variables including triglycerides, non-high-density lipoprotein (HDL)-C, and total apolipoprotein B (HR 1.53, 95% CI 1.35-1.97, p<0.01). The c-statistics showed that addition of RLP-C had a greater incremental effect on the predictive value of conventional risk factors than addition of non-HDL-C or total apolipoprotein B.
RLP-C was superior to non-HDL-C for predicting cardiovascular events in CAD patients with LDL-C levels <100mg/dL on lipid-lowering treatment. Remnant lipoprotein may therefore be an important target for residual risk reduction after LDL-C goals on lipid lowering therapy.
Atherosclerosis 05/2011; 218(1):163-7. · 3.79 Impact Factor
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Toshiaki Yano,
Daisuke Fujioka,
Yukio Saito,
Tsuyoshi Kobayashi,
Takamitsu Nakamura, Jun-ei Obata,
Kenichi Kawabata,
Kazuhiro Watanabe,
Yosuke Watanabe,
Hideto Mishina,
Shun Tamaru,
Kiyotaka Kugiyama
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ABSTRACT: Group V secretory phospholipase A(2) (sPLA(2)-V) is highly expressed in the heart. This study examined (i) the role of sPLA(2)-V in myocardial ischaemia-reperfusion (I/R) injury and (ii) the cooperative action of sPLA(2)-V and cytosolic PLA(2) (cPLA(2)) in myocardial I/R injury, using sPLA(2)-V knockout (sPLA(2)V(-/-)) mice.
Myocardial I/R injury was created by 1 h ligation of the left anterior descending coronary artery, followed by 24 h of reperfusion. The sPLA(2)V(-/-) mice had a 44% decrease in myocardial infarct size, a preservation of echocardiographic LV function (%fractional shortening: 40 ± 3.5 vs. 21 ± 4.6, respectively), and lower content of leucotriene B(4) (LTB(4)) and thromboxane B(2) (TXB(2)) (40 and 37% lower, respectively) in the ischaemic myocardium after I/R compared with wild-type (WT) mice. Intraperitoneal administration of AACOCF3 or MAFP, inhibitors of cPLA(2) activity, decreased myocardial infarct size and myocardial content of LTB(4) and TXB(2) in both genotyped mice. The decrease in myocardial infarct size and content of LTB(4) and TXB(2) after cPLA(2) inhibitor administration was greater in WT mice than in sPLA(2)V(-/-) mice. I/R increased phosphorylation of extracellular signal-related kinase 1/2, c-Jun N-terminal kinase, and p38 mitogen-activated protein kinases in the ischaemic myocardium in association with cPLA(2) phosphorylation. The I/R-induced increase in the phosphorylation of p38 and cPLA(2) was less in sPLA(2)-V(-/-) mice than in WT mice. Pretreatment with the p38 inhibitor SB202190 suppressed an increase in cPLA(2) phosphorylation after I/R in WT mice.
sPLA(2)-V plays an important role in the pathogenesis of myocardial I/R injury partly in concert with the activation of cPLA(2).
Cardiovascular research 01/2011; 90(2):335-43. · 5.80 Impact Factor
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Kenichi Kawabata,
Daisuke Fujioka,
Tsuyoshi Kobayashi,
Yukio Saito, Jun-Ei Obata,
Takamitsu Nakamura,
Toshiaki Yano,
Kazuhiro Watanabe,
Yosuke Watanabe,
Hideto Mishina,
Kiyotaka Kugiyama
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ABSTRACT: Several types of secretory phospholipase A2 (sPLA2) are expressed in lung tissue, yielding various eicosanoids that might cause pulmonary edema. This study examined whether inhibition of sPLA2 activity attenuates acute cardiogenic pulmonary edema in mice. Acute cardiogenic pulmonary edema was induced in C57BL/6J male mice by an increase in heart rate with continuous intravenous infusion of isoproterenol (ISP) (10 mg/kg/h) at 2 weeks after the creation of myocardial infarction by left coronary artery ligation. Just before ISP infusion, a single intraperitoneal injection of 100 mg/kg LY374388, a prodrug of LY329722 that inhibits sPLA2 activity, or vehicle was administered. The ISP infusion after myocardial infarction induced interstitial and alveolar edema on lung histology. Furthermore, it increased the lung-to-body weight ratio, pulmonary vascular permeability evaluated by the Evans blue extravasation method, lung activity of sPLA2, and lung content of thromboxane A2 and leukotriene B4. These changes were significantly attenuated by LY374388 treatment. In Kaplan-Meier analysis, the survival rate during the ISP infusion after myocardial infarction was significantly higher in LY374388- than in vehicle-treated mice. Similar results were obtained with another inhibitor of sPLA2 activity, para-bromophenacyl bromide. In conclusion, inhibition of sPLA2 activity suppressed acute cardiogenic pulmonary edema.
Journal of cardiovascular pharmacology 10/2010; 56(4):369-78. · 2.83 Impact Factor
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Aritaka Makino,
Takamitsu Nakamura,
Mitsumasa Hirano,
Yoshinobu Kitta,
Keita Sano,
Tsuyoshi Kobayashi,
Daisuke Fujioka,
Yukio Saito,
Kazuhiro Watanabe,
Yosuke Watanabe,
Ken-ichi Kawabata, Jun-ei Obata,
Kiyotaka Kugiyama
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ABSTRACT: MIF is proatherogenic and is highly expressed in unstable atherosclerotic plaques. Circulating levels of MIF are increased in patients with impaired glucose tolerance or type 2 diabetes mellitus (IGT/T2DM). We examined whether high circulating levels of macrophage migration inhibitory factor (MIF) are related to increased risk of future coronary events in patients with coronary artery disease (CAD) and IGT/T2DM.
Plasma MIF levels after overnight fast were measured by ELISA in 617 patients with stable CAD including 79 patients with IGT and 215 patients with T2DM. All patients were prospectively followed for 60 months or until occurrence of one of the coronary events: cardiac death, nonfatal myocardial infarction, unstable angina pectoris requiring coronary revascularization.
During the follow-up period, an event occurred in 77 (26%) patients with IGT/T2DM and 50 (15%) patients without IGT/T2DM. In patients with IGT/T2DM, higher MIF levels were a significant predictor of coronary events in a multivariate Cox proportional hazards analysis that included the known risk factors, C-reactive protein levels and medication as covariates (HR 3.3, 95% CI 1.6-8.3, p=0.006). The c-statistic showed that the predictive value of MIF levels was incremental over that of the conventional predictors for coronary events (area under ROC curve; 0.70 and 0.61, respectively, p=0.001). In contrast, MIF levels were not significantly related to future coronary events in patients without IGT/T2DM.
High MIF levels are an independent risk factor for future coronary events in CAD patients with IGT/T2DM.
Atherosclerosis 09/2010; 213(2):573-8. · 3.79 Impact Factor
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Mitsumasa Hirano,
Takamitsu Nakamura,
Yoshinobu Kitta,
Keita Sano,
Yasushi Kodama,
Tsuyoshi Kobayashi,
Daisuke Fujioka,
Yukio Saito,
Toshiaki Yano,
Kazuhiro Watanabe,
Yosuke Watanabe,
Ken-ichi Kawabata, Jun-ei Obata,
Kiyotaka Kugiyama
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ABSTRACT: This study examined whether combined ultrasound assessment of plaque size and echolucency in the carotid artery had an additive effect for predicting coronary events in patients with coronary artery disease (CAD). Ultrasound assessment of either plaque size or echolucency of carotid artery provides prognostic information on coronary events. Combined assessment of plaque size and echolucency of carotid artery has the advantage of obtaining both structural and compositional information in the same artery in a single session.
Ultrasound assessment of carotid plaque maximum intima-media thickness (plaque-IMTmax) and echolucency with integrated backscatter analysis was performed in 413 patients with CAD and carotid plaque. All study patients were followed up prospectively for 54 months or until the occurrence of a coronary event. During the follow-up period, 49 coronary events occurred including 2 cardiac deaths, 10 non-fatal acute myocardial infarctions and 37 recurrent and refractory unstable angina. Multivariate Cox hazards analysis showed plaque-IMTmax alone (HR 2.01, 95%CI 1.30-3.10), plaque echogenicity alone (HR 0.86, 95%CI 0.80-0.91) and combination of high plaque-IMTmax and low echogenicity on categorical data (HR 2.56, 95%CI 1.39-4.74) were independent predictors of coronary events. Analysis using c-statistics showed that plaque-IMTmax and plaque echolucency in combination had a significant incremental effect on the predictive value of the conventional risk factors for coronary events.
Combined ultrasound assessment of carotid plaque size and echolucency has an additive value for prediction of coronary events. Further studies need to evaluate the clinical utility of both ultrasound measurements for risk stratification in CAD.
Atherosclerosis 03/2010; 211(2):451-5. · 3.79 Impact Factor
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Takamitsu Nakamura, Jun-ei Obata,
Mitsumasa Hirano,
Yoshinobu Kitta,
Keita Sano,
Tsuyoshi Kobayashi,
Daisuke Fujioka,
Yukio Saito,
Toshiaki Yano,
Kenichi Kawabata,
Kazuhiro Watanabe,
Yosuke Watanabe,
Hideto Mishina,
Kiyotaka Kugiyama
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ABSTRACT: This study examined whether endothelial vasomotor dysfunction in the brachial artery predicted early renal dysfunction in patients with coronary artery disease (CAD). Endothelial function in the renal vasculature plays an important role in the regulation of renal hemodynamics. As endothelial dysfunction is a systemic disorder, there may be a relationship between endothelial function in the brachial artery and renal vasculature.
Flow-mediated endothelium-dependent dilation (FMD) in brachial artery and renal functional parameters were measured in 757 patients with CAD without macroalbuminuria.
In a cross-sectional data, an impaired FMD was associated with higher serum creatinine levels and urinary albumin excretion (UAE), lower creatinine clearance rate and estimated glomerular filtration rate (eGFR) at baseline in multiple linear regression analysis. In a follow-up study including a subgroup of 448 patients with normal renal function (serum creatinine level <1.0mg/dL, UAE <25mg/day and eGFR ≥ 60 mL/min/1.73 m(2) at baseline), 96 patients had an endpoint of early stage renal dysfunction (serum creatinine levels ≥ 1.2mg/dL, UAE ≥ 30 mg/day and/or eGFR <60 mL/min/1.73 m(2)) during 12 month follow-up. Multivariate logistic regression analysis showed that impaired FMD was significantly associated with progression to the early stage renal dysfunction after adjustment with age, diabetes mellitus, hypertension and C-reactive protein levels.
Endothelial vasomotor dysfunction in the brachial artery is independently associated with progression from normal renal function to early stage renal dysfunction in patients with CAD. Measurement of FMD may therefore be useful for assessing risk of future renal dysfunction.
International journal of cardiology 11/2009; 148(2):183-8. · 7.08 Impact Factor
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Tsuyoshi Kobayashi,
Yosuke Watanabe,
Yukio Saito,
Daisuke Fujioka,
Takamitsu Nakamura, Jun-ei Obata,
Yoshinobu Kitta,
Toshiaki Yano,
Kenichi Kawabata,
Kazuhiro Watanabe,
Hideto Mishina,
Sadahiro Ito,
Kiyotaka Kugiyama
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ABSTRACT: Glutamate-cysteine ligase (GCL), a rate-limiting enzyme for glutathione (GSH) synthesis, is composed of catalytic and modifier subunits. This study examined the pathogenic role of GCL modifier subunits (GCLM) in myocardial ischaemia-reperfusion (I/R) injury using mice lacking the GCLM (GCLM(-/-)).
The GCLM(-/-)mice had an increase in myocardial I/R injury and apoptosis in ischaemic myocardium compared with GCLM(+/+) mice. There was a decrease in mitochondrial glutathione (GSH) levels in ischaemic myocardium that was more pronounced in GCLM(-/-) mice than in GCLM(+/+) mice (12 vs. 55% of baseline GCLM(+/+), respectively). The ESR signal intensity of the dimethyl-1-pyrroline-N-oxide-hydroxyl radical adducts in ischaemic myocardium was higher in GCLM(-/-) mice than in GCLM(+/+) mice. Hypoxia-reoxygenation induced greater mitochondrial damage in cultured cardiomyocytes from GCLM(-/-) mice than from GCLM(+/+) mice, as evidenced by a reduced membrane potential and increased protein carbonyl content in isolated mitochondria, together with enhanced cytochrome c translocation into the cytosol. Administration of GSH ethyl-ester attenuated myocardial I/R injury and reversed the mitochondrial damage in parallel with the mitochondrial GSH restoration in the myocardium or the cardiomyocytes of GCLM(-/-) mice.
GCLM(-/-) mice were susceptible to myocardial I/R injury partly through an increased vulnerability of mitochondria to oxidative damage owing to mitochondrial GSH reduction.
Cardiovascular research 10/2009; 85(4):785-95. · 5.80 Impact Factor
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Mitsumasa Hirano,
Takamitsu Nakamura,
Yoshinobu Kitta,
Toshiaki Yano,
Tsuyoshi Kobayashi,
Keita Sano,
Daisuke Fujioka,
Yukio Saito,
Yasushi Kodama,
Ken-ichi Kawabata,
Kazuto Nakamura, Jun-ei Obata,
Kiyotaka Kugiyama
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ABSTRACT: This study examined whether pioglitazone, an agonist of peroxisome proliferator-activated receptor gamma, may stabilize vulnerable plaque with use of ultrasound evaluation of carotid artery plaque echolucency in patients with acute coronary syndrome (ACS) and type 2 diabetes mellitus (DM).
Treatment with pioglitazone (15 or 30mg/day, n=31) or placebo (n=30) was randomly assigned and initiated within 5 days after the onset of ACS in 61 patients with type 2 DM and echolucent carotid plaques. Vulnerable carotid plaques were assessed by measuring plaque echolucency using carotid ultrasound with integrated backscatter (IBS) before, at 2 weeks, and 1 month and 6 months after initiation of treatment. An increase in IBS value reflects an increase in carotid plaque echogenicity. Calibrated IBS value (intima-media IBS value minus adventitia IBS value) of echolucent carotid plaques did not change at 2 weeks but was significantly increased at 1 month after treatment in the pioglitazone group but not in the placebo group. The increase in calibrated IBS value was not significantly correlated with the effect of pioglitazone on glycemia.
Pioglitazone rapidly improved carotid plaque echolucency within 1 month of therapy initiation in patients with ACS and type 2 DM.
Atherosclerosis 08/2008; 203(2):483-8. · 3.79 Impact Factor
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Takamitsu Nakamura, Jun-Ei Obata,
Yoshinobu Kitta,
Hajime Takano,
Tsuyoshi Kobayashi,
Daisuke Fujioka,
Yukio Saito,
Yasushi Kodama,
Kenichi Kawabata,
Akira Mende,
Toshiaki Yano,
Mitsumasa Hirano,
Keita Sano,
Kazuto Nakamura,
Kiyotaka Kugiyama
[show abstract]
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ABSTRACT: We determined time course of stabilization of echolucent carotid plaques by statin therapy in patients with acute coronary syndrome (ACS). Treatment with 4 mg/d pitavastatin (n = 33) or placebo (n = 32) was initiated within 3 days after onset of ACS in 65 patients with echolucent carotid plaque. Vulnerable carotid plaques were assessed by measuring plaque echolucency using carotid ultrasound with integrated backscatter (IBS) analysis before and 1 month after treatment in all patients. The calibrated IBS value (intima-media IBS value minus adventia IBS) of vulnerable carotid plaques favorably changed at 1 month after treatment in both groups, but the echolucency at 1 month improved more in the pitavastatin than in the placebo group (pitavastatin group: -18.7 +/- 3.3 dB at pretreatment versus -12.7 +/- 2.3 dB at 1 month *P < 0.001; placebo: -19.0 +/- 3.5 dB versus -16.9 +/- 3.2 dB, P < 0.05, *P < 0.01 versus the value at 1 month in placebo group). Levels of CRP, VEGF, and TNFalpha at 1 month were significantly lower in pitavastatin than placebo group. In conclusion, pitavastatin improved carotid plaque echolucency within 1 month of therapy in patients with ACS, in association with decrease in the inflammatory biomarkers related to vulnerable plaques.
Journal of Cardiovascular Pharmacology 04/2008; 51(4):365-71. · 2.29 Impact Factor
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ABSTRACT: Metabolic syndrome is prevalently associated with stroke. Triglyceride-rich lipoproteins contribute to atherothrombotic complications in metabolic syndrome. This study examined whether high levels of remnant lipoprotein, atherogenic triglyceride-rich lipoprotein, may be associated with future ischemic stroke in metabolic syndrome.
We followed up 292 consecutive patients with metabolic syndrome meeting ATP III criteria and mild carotid plaques for a period of </=24 months until occurrence of an ischemic stroke. Remnant lipoprotein (remnant-like lipoprotein particles cholesterol; RLP-C) were measured by an immunoseparation method. Twenty-two ischemic stroke events occurred during follow-up. A multivariate Cox proportional hazards models showed that high RLP-C levels were a significant and independent predictor of ischemic stroke events (p<0.01). Echolucent carotid plaques were also a significant predictor of ischemic stroke that was independent of other carotid ultrasound parameters in Cox proportional hazards models (p<0.01). High RLP-C levels were intimately and independently associated with carotid plaque echolucency (p<0.01).
High RLP-C levels are an independent risk factor for future ischemic strokes in metabolic syndrome. High RLP-C levels may be related to echolucent carotid plaque, partly accounting for high risk for ischemic stroke in metabolic syndrome.
Atherosclerosis 03/2008; 202(1):234-40. · 3.79 Impact Factor
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ABSTRACT: Because metabolic syndrome is associated with cardiovascular diseases, its association with the risk of paroxysmal atrial fibrillation (PAF) and/or atrial flutter (PAFL) was examined in the present study.
A prospective analysis was performed in 592 consecutive hospitalized patients without obvious structural heart diseases. Sinus rhythm was confirmed by electrocardiography in all patients. PAF/PAFL occurred in 32 (5%) and metabolic syndrome was present in 127 (21%) of the patients enrolled. PAF/PAFL occurred in 12 (9%) of the patients with metabolic syndrome, but only 20 (4%) of patients without metabolic syndrome (p=0.02). Multivariate logistic regression analysis showed that metabolic syndrome was a significant risk factor for PAF/PAFL that was independent of left atrial diameter (> 44 mm) or age (> 70 years) (odds ratio (OR) 2.8, 95% confidence interval (CI) 1.3-6.2, p<0.01). Among the 5 components of the metabolic syndrome, body mass index > or = 25 kg/m2 was the most strongly associated with PAF/PAFL (OR; 3.0, 95% CI 1.2-7.4, p=0.02).
Metabolic syndrome is highly associated with PAF/PAFL in patients without structural heart diseases and obesity may be an underlying mechanism for the higher prevalence.
Circulation Journal 03/2007; 71(2):252-5. · 3.77 Impact Factor
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ABSTRACT: Increased pulse pressure (PP) is recognized as a risk factor for cardiovascular disease, especially in elderly patients. However, blood pressure (BP) is known to have a circadian variation. Therefore, this study asked whether or not PP has a circadian variation and, if so, whether a circadian variation of PP has clinical importance. Ambulatory BP monitoring (every 30 min for 48 h) was performed in 255 patients with untreated essential hypertension (24 to 82 years old; mean: 52+/-12 years). Left ventricular mass index (LVMI) was estimated from M-mode echocardiography. PP was decreased during nighttime (10+/-11% reduction from daytime PP). Multivariate linear regression analysis showed that, among four variables-the degree of nighttime PP reduction, daytime PP, 48-h systolic BP, and nondipper hypertension-the degree of nighttime PP reduction had the strongest (inverse) correlation with LVMI in a subgroup of elderly patients (> or =60 years old, n =67) (standardized regression coefficient=-0.32, p =0.02), whereas this association was not significant in the whole patient population unclassified by age. Furthermore, a blunted reduction of nighttime PP in combination with nondipper hypertension was an incremental risk for increase in LVMI in the elderly patients. In conclusion, PP is reduced during nighttime, but the degree of reduction varies among patients. The blunted reduction of nighttime PP is a risk for left ventricular hypertrophy, an established predictor of hypertension-induced cardiovascular events, and it may thus play a role in cardiovascular complications, especially in elderly patients with nondipper hypertension.
Hypertension Research 09/2004; 27(8):573-9. · 2.58 Impact Factor
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Akira Matsumori,
Hajime Takano, Jun-ei Obata,
Satoshi Takeda,
Naohiko Tsuyuguchi,
Koh Ono,
Masaharu Okada,
Tadashi Miyamoto,
Tomokazu Ohnishi,
Yasushi Daikuhara,
Shigetake Sasayama
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ABSTRACT: Circulating levels of hepatocyte growth factor (HGF) are increased in the early stage of an acute myocardial infarction because of arterial thrombosis. The purpose of this study was to use a new sensitive enzyme-linked immunosorbent assay to investigate whether circulating HGF is increased in patients with cerebral infarction. Circulating HGF was measured in 32 patients with cerebral infarction on admission to hospital and on days 2, 3, 7 and 14 after the onset of symptoms. Serum HGF levels exceeded the mean value +2SD (329pg/ml) measured in controls in 10 of 20 patients (50%) within 6 h after onset and in 15 of 32 patients (47%) within 24 h. Plasma D-dimer was increased in more than half of the patients with elevated HGF values. HGF levels in 16 patients who were measured serially were persistently increased throughout the study period. The results suggests that circulating HGF is a reliable early marker of cerebral infarction, and that this new sensitive HGF assay may be useful for diagnosing cerebral thrombosis.
Circulation Journal 03/2002; 66(2):216-8. · 3.77 Impact Factor
