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Featured researches published by Mutsumi Iwamoto.


Cardiovascular Diabetology | 2011

Association of increased plasma adipocyte fatty acid-binding protein with coronary artery disease in non-elderly men

Masayuki Doi; Toru Miyoshi; Satoshi Hirohata; Kazufumi Nakamura; Shinichi Usui; Ko Takeda; Mutsumi Iwamoto; Shozo Kusachi; Kengo Kusano; Hiroshi Ito

BackgroundAdipocyte fatty acid-binding protein (A-FABP) has been reported to play critical roles in the development of atherosclerosis. We investigated whether an increased in plasma A-FABP level can be independently associated with the presence of coronary artery disease (CAD).MethodsTwo hundred eleven consecutive male patients (mean age: 66 years, range: 33-87 years) were enrolled from inpatients who underwent coronary angiography. Age-matched male subjects (n = 211) having no evidence of CAD served as controls. Plasma A-FABP levels were measured by enzyme-linked immunosorbent assays.ResultsPlasma A-FABP levels in CAD patients were significantly higher than in control subjects (median [IQR], 20.6 [15.7-27.8] ng/mL vs. 15.1 [11.7-19.9] ng/mL, p < 0.01). Multivariate logistic regression analysis revealed that an increased plasma A-FABP level was independently associated with the presence of CAD in all subjects (adjusted odds ratio: 1.76, 95% confidence interval: 1.14 to 2.70, p = 0.01). Furthermore, sub-analysis based on age showed that this association remained significant in subjects aged < 65 years (adjusted odds ratio: 3.06, 95% confidence interval: 1.34 to 6.98, p < 0.01), but not in subjects aged ≥65 years.ConclusionsIncreased plasma A-FABP in non-elderly men had a significant association with the presence of CAD, independent of established CAD risk factors.


Hypertension Research | 2010

Connective tissue growth factor induction in a pressure-overloaded heart ameliorated by the angiotensin II type 1 receptor blocker olmesartan.

Mutsumi Iwamoto; Satoshi Hirohata; Hiroko Ogawa; Takashi Ohtsuki; Ryoko Shinohata; Toru Miyoshi; Faruk O Hatipoglu; Shozo Kusachi; Kazuhide Yamamoto; Yoshifumi Ninomiya

Connective tissue growth factor (CTGF) is a secreted protein that regulates fibrosis. We hypothesized that CTGF is induced in a pressure-overloaded (PO) heart and that blocking the angiotensin II type 1 receptor would reduce CTGF expression. Accordingly, we administered olmesartan and compared its effects with other antihypertensive drugs in a PO heart. CTGF induction was determined in a rat PO model, and olmesartan, hydralazine or saline was continuously administered. The effects of olmesartan on CTGF induction, myocyte hypertrophy and fibrosis were evaluated. The effect of olmesartan on cardiac function was also examined in CTGF- and transforming growth factor-beta 1 (TGF-β1)-infused rats. CTGF was increased in the PO heart 3 days after aortic banding and was markedly distributed around the perivascular fibrotic area. After 28 days, blood pressure was not significantly different in the olmesartan and hydralazine groups, but olmesartan treatment reduced CTGF distribution in PO hearts. Olmesartan was associated with a significantly reduced myocyte hypertrophy index (4.77±0.48 for olmesartan and 6.05±1.45 for saline, P<0.01), fibrosis area (32.0±15.5% compared with the saline group, P<0.05) and serum TGF-β1 level (62.6±10.6 ng ml−1 for olmesartan and 84.4±7.2 ng ml−1 for hydralazine, P<0.05). In addition, cardiac function was significantly preserved in the olmesartan group compared with the saline group. Finally, olmesartan ameliorated the cardiac dysfunction in CTGF- and TGF-β1-infused rats. Olmesartan attenuated CTGF induction, reduced perivascular fibrosis and ameliorated cardiac dysfunction in a PO heart. Our results provide insight into the beneficial effects of olmesartan on PO hearts, independent of blood-pressure lowering.


International Journal of Cardiology | 2014

Early eicosapentaenoic acid treatment after percutaneous coronary intervention reduces acute inflammatory responses and ventricular arrhythmias in patients with acute myocardial infarction: A randomized, controlled study

Masayuki Doi; Kazumasa Nosaka; Toru Miyoshi; Mutsumi Iwamoto; Masahito Kajiya; Keisuke Okawa; Rie Nakayama; Wataru Takagi; Ko Takeda; Satoshi Hirohata; Hiroshi Ito

OBJECTIVE We examined whether early loading of eicosapentaenoic acid (EPA) reduces clinical adverse events by 1 month, accompanied by a decrease in C-reactive protein (CRP) values in patients with acute myocardial infarction (MI). BACKGROUND Acute MI triggers an inflammatory reaction, which plays an important role in myocardial injury. EPA could attenuate the inflammatory response. METHODS This prospective, open-label, blinded endpoint, randomized trial consisted of 115 patients with acute MI. They were randomly assigned to the EPA group (57 patients) and the control group (58 patients). After percutaneous coronary intervention (PCI), 1800 mg/day of EPA was initiated within 24h. The primary endpoint was composite events, including cardiac death, stroke, re-infarction, ventricular arrhythmias, and paroxysmal atrial fibrillation within 1 month. RESULTS Administration of EPA significantly reduced the primary endpoint within 1 month (10.5 vs 29.3%, p=0.01), especially the incidence of ventricular arrhythmias (7.0 vs 20.6%, p=0.03). Peak CRP values after PCI in the EPA group were significantly lower than those in the control group (median [interquartile range], 8.2 [5.6-10.2] mg/dl vs 9.7 [7.6-13.9] mg/dl, p<0.01). Logistic regression analysis showed that EPA use was an independent factor related to ventricular arrhythmia until 1 month, with an odds ratio of 0.29 (95% confidence interval, 0.09 to 0.96, p=0.04). CONCLUSIONS Early EPA treatment after PCI in the acute stage of MI reduces the incidence of ventricular arrhythmias, and lowers CRP values.


International Journal of Cardiology | 2017

Early initiation of eicosapentaenoic acid and statin treatment is associated with better clinical outcomes than statin alone in patients with acute coronary syndromes: 1-year outcomes of a randomized controlled study.

Kazumasa Nosaka; Toru Miyoshi; Mutsumi Iwamoto; Masahito Kajiya; Keisuke Okawa; Saori Tsukuda; Fumi Yokohama; Masahiro Sogo; Tomoyuki Nishibe; Naoaki Matsuo; Satoshi Hirohata; Hiroshi Ito; Masayuki Doi

BACKGROUND Early initiation of EPA treatment in combination with a statin within 24h after percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (MI) reduces inflammation and ventricular arrhythmia compared with statin monotherapy; however, the impact of early initiation of EPA treatment on cardiovascular events is unclear. We determined whether early eicosapentaenoic acid (EPA) treatment in patients with acute coronary syndrome (ACS) reduces adverse cardiovascular events. METHODS This prospective, open-label, blind end point-randomized trial consisted of 241 patients with ACS. Patients were randomly assigned to receive pitavastatin (2mg/day) with or without 1800mg/day of EPA initiated within 24h after PCI. The primary endpoint was defined as cardiovascular events occurring within 1year, including death from a cardiovascular cause, nonfatal stroke, nonfatal MI and revascularization. RESULTS The mean EPA/arachidonic acid ratio at follow-up was 0.40 in the control group and 1.15 in the EPA group. A primary endpoint event occurred in 11 patients (9.2%) in the EPA group and 24 patients (20.2%) in the control group (absolute risk reduction, 11.0%; hazard ratio, 0.42; 95% confidence interval, 0.21 to 0.87; P=0.02). Notably, death from a cardiovascular cause at 1year was significantly lower in the EPA group than in the control group (0.8% vs. 4.2%, P=0.04). CONCLUSIONS Early initiation of treatment with EPA combined with statin after successful primary PCI reduced cardiovascular events after ACS. CLINICAL TRIAL REGISTRATION UMIN Clinical Trials Registry (UMIN-CTR); Registry Number, UMIN000016723; URL, http://www.umin.ac.jp/ctr/index-j.htm.


Atherosclerosis | 2014

Low serum level of secreted frizzled-related protein 5, an anti-inflammatory adipokine, is associated with coronary artery disease.

Toru Miyoshi; Masayuki Doi; Shinichi Usui; Mutsumi Iwamoto; Masahito Kajiya; Ko Takeda; Kazumasa Nosaka; Rie Nakayama; Keisuke Okawa; Wataru Takagi; Kazufumi Nakamura; Satoshi Hirohata; Hiroshi Ito

OBJECTIVE Secreted frizzled-related protein 5 (SFRP5) is an anti-inflammatory adipokine that is associated with insulin resistance in animals. To extend these observations to humans, we investigated the association of serum SFRP5 levels in subjects with and without coronary artery disease (CAD). METHODS Subjects (n=185, 68±11 years, 79% male) suspected of having CAD were enrolled in the study and were divided into two groups, CAD and non-CAD subjects, according to the results of their coronary angiographies. Serum SFRP5 levels of the subjects were measured by an enzyme-linked immunosorbent assay. RESULTS The serum SFRP5 levels in the subjects with CAD were significantly lower than those in the non-CAD subjects (median [interquartile range]: 47.7 [26.6] vs. 52.4 [29.6] ng/mL, respectively; p=0.02). The serum SFRP5 levels significantly correlated with body mass index, the homeostasis model of assessment of insulin resistance, adiponectin levels, and CAD severity. Multivariate logistic regression analysis revealed that a decreased serum SFRP5 level (log transformed) was independently associated with CAD for all subjects (adjusted odds ratio, 0.36; 95% confidence interval, 0.14-0.94; p=0.03). CONCLUSION Serum SFRP5 levels are significantly associated with CAD in humans, suggesting that low SFRP5 levels may contribute to CAD.


Cardiovascular Diabetology | 2012

Elevated serum adipocyte fatty acid-binding protein concentrations are independently associated with renal dysfunction in patients with stable angina pectoris

Mutsumi Iwamoto; Toru Miyoshi; Masayuki Doi; Ko Takeda; Masahito Kajiya; Kazumasa Nosaka; Rie Nakayama; Satoshi Hirohata; Shinichi Usui; Shozo Kusachi; Kosuke Sakane; Kazuhfumi Nakamura; Hiroshi Ito

BackgroundChronic kidney disease (CKD) is associated with cardiovascular events. Adipocyte fatty acid-binding protein (A-FABP) plays an important role in atherosclerosis. We investigated whether plasma A-FABP is involved in renal function in patients with stable angina pectoris.MethodsA total of 221 patients with significant coronary artery stenosis were enrolled after coronary angiography. CKD was defined as an estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m2. The severity of coronary stenosis was assessed using a modified Gensini score and coronary angiography. Serum A-FABP levels were determined by enzyme-linked immunosorbent assay.ResultsSerum A-FABP levels were significantly correlated with both eGFR (r = -0.41, p < 0.01) and the severity of coronary artery stenosis (r = 0.16, p = 0.02), and these relationships remained significant after adjusting for confounding factors. The prevalence of CKD and multi-vessel disease was significantly higher among patients with serum A-FABP levels above the median value of 20.3 ng/ml than among patients with serum A-FABP levels below the median value (57% vs. 27%, p < 0.01 and 64% vs. 48%, p = 0.02, respectively). Multivariate analysis revealed that the presence of three-vessel disease in comparison with single-vessel disease was independently associated with the higher A-FABP (per doubling) (odds ratio; 2.26, 95% confidential interval; 1.28-3.98, p < 0.01) and tended to be associated with the lower eGFR (p = 0.06).ConclusionSerum A-FABP may have a significant role in the interplay between renal dysfunction and coronary atherosclerosis.


Heart and Vessels | 2013

Serum adipocyte fatty acid-binding protein is independently associated with complex coronary lesions in patients with stable coronary artery disease

Masahito Kajiya; Toru Miyoshi; Masayuki Doi; Shinichi Usui; Mutsumi Iwamoto; Ko Takeda; Kazumasa Nosaka; Rie Nakayama; Satoshi Hirohata; Shozo Kusachi; Kazufumi Nakamura; Hiroshi Ito

The association between circulating adipocyte fatty acid-binding protein (A-FABP) levels and coronary artery disease (CAD) is reported. We assessed whether plasma A-FABP levels are associated with angiographic coronary lesion morphology in patients with stable CAD. Serum A-FABP levels were analyzed in 115 patients with stable CAD (mean age 69 ± 10 years; 80 % men). These patients were angiographically studied and divided into two groups: simple lesions (n = 34) and complex lesions (n = 81). We also compared 50 age- and gender-matched controls with no evidence of CAD. Serum A-FABP levels in patients with stable CAD were significantly higher than those in controls. In patients with stable CAD, serum A-FABP levels were significantly higher in patients with complex lesions than in those with simple lesions: median (25th–75th percentile), 23.4 (17.7–30.8) vs 18.2 (12.2–24.7) ng/ml, P < 0.01. Serum A-FABP levels were also significantly associated with angiographic scores of extent of coronary lesion (r = 0.21, P = 0.02). Multiple logistic analysis that included dyslipidemia, statin therapy, and extent score demonstrated that serum A-FABP was independently associated with complex lesions. The multiple adjusted odds ratio for a complex lesion with a serum A-FABP level (per doubling) was 2.38 (95 % confidence interval, 1.03–6.41; P = 0.03). High serum A-FABP levels were significantly associated with complex coronary lesions in patients with stable CAD, suggesting that high A-FABP levels may be involved in coronary plaque vulnerability.


Journal of the American College of Cardiology | 2014

EARLY LOADING OF OMEGA-3 FATTY ACIDS DECREASES INFLAMMATION AND IN-HOSPITAL EVENTS IN PATIENTS WITH ACUTE MYOCARDIAL INFARCTION UNDERGOING PERCUTANEOUS CORONARY INTERVENTION

Kazumasa Nosaka; Masayuki Doi; Toru Miyoshi; Keiichi Mashima; Mutsumi Iwamoto; Masahito Kajiya; Keisuke Okawa; Norifumi Kawakita; Hiroshi Ito

GISSI prevention trial demonstrated that long term assumption of omega-3 fatty acids improves significantly the prognosis of patients with a history of myocardial infarction (MI), mainly due to anti-arrhythmic effects. However, the acute effect of omega-3 fatty acids especially on arrhythmic events


Acta Cardiologica | 2006

Changes in escape rhythms several years after radiofrequency ablation of the atrioventricular junction combined with pacemaker implantation.

Hiroshi Kawamura; Kazuyoshi Hina; Shozo Kusachi; Kochichiro Iwasaki; Keizo Yamamoto; Takashi Murakami; Masaaki Murakami; Mutsumi Iwamoto; Shigashi Kamikawa; Yasushi Shiratori

Objective#x2014; Escape rhythm is thought to play a considerable role in protection against adverse outcome due to pacemaker malfunction.We studied the escape rhythms in 32patients with supraventricular tachyarrhythmia refractory to medical therapy who underwent radiofrequency ablation of the atrioventricular junction combined with implantation of a pacemaker. Methods and results — We performed the escape rhythm analysis immediately and 2.6±1.9years after the radiofrequency ablation by decreasing the pacing rate. In the initial study, escape rhythms (41±8beats/min) were documented in 20patients (63%). Non-cardiac death occurred in 3patients with escape rhythm, and cardiac death occurred in 1patient without escape rhythm. In the followup study, escape rhythms were detected in 22 of 28patients (79%). Escape rhythm had developed in 6 (55%) of 11patients who were without escape rhythm initially, while escape rhythm disappeared in 1 of 17 (5.9%) patients who had escape rhythm initially. The changes in escape rhythm were not related to QRS width of the intrinsic beat.There was no correlation between the number of radiofrequency applications or the ratio between atrial and ventricular electrocardiogram voltages of radiofrequency applications and the development of escape rhythms. Conclusions — The present long-term follow-up study demonstrated that the emergence of an escape rhythm increased several years after ablation, but was unrelated to procedural factors.There are, however, certain patients in whom the disappearance of escape rhythms occur. The evaluation of escape rhythms is thus necessary to determine the risk associated with pacemaker failure.


Clinical Biochemistry | 2008

Serum interferon-gamma-inducible protein 10 level was increased in myocardial infarction patients, and negatively correlated with infarct size

Satoshi Hirohata; Toru Miyoshi; Hiroko Ogawa; Shinichi Usui; Ryoko Shinohata; Mutsumi Iwamoto; Tomoki Kitawaki; Shozo Kusachi; Kosaku Sakaguchi; Tohru Ohe

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Hiroshi Ito

Fukushima Medical University

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