Daihiko Hakuno

National Defense Medical College, Tokorozawa, Saitama-ken, Japan

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Publications (22)94.46 Total impact

  • [show abstract] [hide abstract]
    ABSTRACT: The patient was a 78-year-old man. In August 2007, he underwent catheter ablation for atrial fibrillation after taking bepridil for 3 weeks. Soon after the ablation, he experienced frequent atrial extrasystoles and began taking bepridil again on the day he left the hospital. Six days after discharge, he was readmitted to our hospital with dyspnea and was diagnosed with acute heart failure. The patient had no recurrence of atrial fibrillation, so the administration of bepridil was stopped. His dyspnea was eased using standard therapy for heart failure and he was discharged from our hospital. In March 2011, he had a recurrence of atrial fibrillation and was readmitted to our hospital. The administration of bepridil was initiated to defibrillate the atrial fibrillation. Although bepridil stopped the atrial fibrillation by the third day, he presented with dyspnea and fever on the fourth day. A chest radiograph showed bilateral interstitial patterns that radiated from the pulmonary hilum. He was treated for acute heart failure and bacterial pneumonia, but this was ineffective. We suspected that the interstitial pneumonia was caused by bepridil. Corticosteroid therapy dramatically improved his symptoms. This was a rare case of acute drug-induced interstitial pneumonia caused by repeated exposure to bepridil.
    Journal of Arrhythmia 02/2013; 29(1):39–42.
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    ABSTRACT: Insulin signaling comprises 2 major cascades: the insulin receptor substrate/phosphatidylinositol 3'-kinase/protein kinase B and Ras/Raf/mitogen-activated protein kinase/kinase/ERK pathways. While many studies on the tissue-specific effects of the insulin receptor substrate/phosphatidylinositol 3' -kinase/protein kinase B pathway have been conducted, the role of the other cascade in tissue-specific insulin resistance has not been investigated. High glucose/fatty acid toxicity, inflammation, and oxidative stress, all of which are associated with insulin resistance, can activate ERK. The liver plays a central role in metabolism, and hepatosteatosis is associated with vascular diseases. The aim of study was to elucidate the role of hepatic ERK2 in hepatosteatosis, metabolic remodeling, and endothelial dysfunction. We created liver-specific ERK2 knockout mice and fed them with a high-fat/high-sucrose diet for 20 weeks. The high-fat/high-sucrose diet-fed liver-specific ERK2 knockout mice exhibited a marked deterioration in hepatosteatosis and metabolic remodeling represented by impairment of glucose tolerance and decreased insulin sensitivity without changes in body weight, blood pressure, and serum cholesterol/triglyceride levels. In the mice, endoplasmic reticulum stress was induced together with decreased mRNA and protein expressions of hepatic sarco/endoplasmic reticulum Ca(2+)-ATPase 2. In a hepatoma cell line, inhibition of ERK activation- induced endoplasmic reticulum stress only in the presence of palmitate. Vascular reactive oxygen species were elevated with upregulation of nicotinamide adenine dinucleotide phosphate oxidase1 (Nox1) and Nox4 and decreased phosphorylation of endothelial nitric oxide synthase, which resulted in the remarkable endothelial dysfunction in high-fat/high-sucrose diet-fed liver-specific ERK2 knockout mice. Hepatic ERK2 suppresses endoplasmic reticulum stress and hepatosteatosis in vivo, which results in protection from vascular oxidative stress and endothelial dysfunction. These findings demonstrate a novel role of hepatic ERK2 in obese-induced insulin resistance in the protection from hepatovascular metabolic remodeling and vascular diseases.
    Journal of the American Heart Association. 01/2013; 2(4):e000361.
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    JACC. Cardiovascular imaging 05/2012; 5(5):570-1. · 14.29 Impact Factor
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    ABSTRACT: The anti-oxidant enzyme copper/zinc superoxide dismutase (CuZnSOD) metabolizes superoxide anion (O(2)(-)) in vascular cells. However, the role of CuZnSOD in vascular injury remains poorly understood. Using CuZnSOD-deficient (CuZnSOD(-/-)) mice and wild-type (WT) mice, we investigated morphometric changes and the role of O(2)(-) in vascular remodeling after femoral artery injury induced by an external vascular cuff model. Three days post-injury, inflammatory cell infiltration increased significantly. Moreover, the percent positive area of tumor necrosis factor-α (TNF-α), intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) in media were higher in CuZnSOD(-/-) mice than in WT mice (TNF-α: 34.8±8.4% versus 18.8±5.6%, p < 0.05, ICAM-1: 29.6±6.5% versus 11.0±2.8%, p < 0.05, VCAM-1: 23.5±7.5% versus 3.7±1.1%, p < 0.05). mRNA expression of iNOS was markedly increased in CuZnSOD(-/-) mice with cuff injury. Dihydroethidine staining revealed increased levels of vascular O(2)(-) in media from CuZnSOD(-/-) mice. Although neointimal formation remained unchanged, 14 days postinjury, we observed degeneration of the media, and the media/vessel wall ratio increased in CuZnSOD(-/-) mice (40.4±2.1% versus 26.8±1.4%, p < 0.05). Furthermore, SMemb/MHC-B-stained lesions increased markedly in CuZnSOD(-/-) mice. CuZnSOD-deficiency promoted inflammation, expressed adhesion molecules, and altered the structure of the media post-injury. Our results suggest that O(2)(-) participates importantly in the progression of early stage vascular inflammation, resulting in vascular remodeling in media but not neointimal formation, post-injury.
    Journal of atherosclerosis and thrombosis 09/2011; 18(11):1009-17. · 2.93 Impact Factor
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    ABSTRACT: The aging of populations worldwide and the habitual consumption of food high in calories and cholesterol have led to recent increases in morbidity from calcific aortic valve disease. At the same time, rupture of the chordae tendineae cordis, which is a component of the mitral valve complex, is one of the major causes of mitral regurgitation. Surgery is the basis of treatment for these diseases, and little is known about their causes and mechanisms. A balance of angiogenetic and angioinhibitory factors is crucial for normal development and homeostasis of many organs. Although the heart is a vascular-rich organ, most of the cardiac valve complex is avascular like cartilage and tendons. Our studies have focused on the role of angiogenetic factors expressed in the cartilage and tendons in cardiac valve homeostasis. Recently, we found that chondromodulin-I, tenomodulin, and periostin play essential roles in degeneration and/or rupture of the cardiac valve complex by controlling angiogenesis and matrix metalloproteinase production. Here, we review the mechanistic insights provided by these studies and the proposed roles of angiogenetic factors in cardiac valve homeostasis and disease.
    Journal of Cardiovascular Translational Research 08/2011; 4(6):727-40. · 3.06 Impact Factor
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    ABSTRACT: Valvular heart disease (VHD) is the term given to any disease process involving one or more of the heart valves. The condition can be congenital or acquired, for example as a result of atherosclerosis or rheumatic fever. Despite its clinical importance, the molecular mechanisms underlying VHD remain unknown. We investigated the pathophysiologic role and molecular mechanism of periostin, a protein that plays critical roles in cardiac valve development, in degenerative VHD. Unexpectedly, we found that periostin levels were drastically increased in infiltrated inflammatory cells and myofibroblasts in areas of angiogenesis in human atherosclerotic and rheumatic VHD, whereas periostin was localized to the subendothelial layer in normal valves. The expression patterns of periostin and chondromodulin I, an angioinhibitory factor that maintains cardiac valvular function, were mutually exclusive. In WT mice, a high-fat diet markedly increased aortic valve thickening, annular fibrosis, and MMP-2 and MMP-13 expression levels, concomitant with increased periostin expression; these changes were attenuated in periostin-knockout mice. In vitro and ex vivo studies revealed that periostin promoted tube formation and mobilization of ECs. Furthermore, periostin prominently increased MMP secretion from cultured valvular interstitial cells, ECs, and macrophages in a cell type-specific manner. These findings indicate that, in contrast to chondromodulin I, periostin plays an essential role in the progression of cardiac valve complex degeneration by inducing angiogenesis and MMP production.
    The Journal of clinical investigation 07/2010; 120(7):2292-306. · 15.39 Impact Factor
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    ABSTRACT: Rupture of the chordae tendineae cordis (CTC) is a well-known cause of mitral regurgitation. Despite its importance, the mechanisms by which the CTC is protected and the cause of its rupture remain unknown. CTC is an avascular tissue. We investigated the molecular mechanisms underlying the avascularity of CTC and the correlation between avascularity and CTC rupture. We found that tenomodulin, which is a recently isolated antiangiogenic factor, was expressed abundantly in the elastin-rich subendothelial outer layer of normal rodent, porcine, canine, and human CTC. Conditioned medium from cultured CTC interstitial cells strongly inhibited tube formation and mobilization of endothelial cells; these effects were partially inhibited by small-interfering RNA against tenomodulin. The immunohistochemical analysis was performed on 12 normal and 16 ruptured CTC obtained from the autopsy or surgical specimen. Interestingly, tenomodulin was locally absent in the ruptured areas of CTC, where abnormal vessel formation, strong expression of vascular endothelial growth factor-A and matrix metalloproteinases, and infiltration of inflammatory cells were observed, but not in the normal or nonruptured area. In anesthetized open-chest dogs, the tenomodulin layer of tricuspid CTC was surgically filed, and immunohistological analysis was performed after several months. This intervention gradually caused angiogenesis and expression of vascular endothelial growth factor-A and matrix metalloproteinases in the core collagen layer in a time-dependent manner. These findings provide evidence that tenomodulin is expressed universally in normal CTC in a concentric pattern and that local absence of tenomodulin, angiogenesis, and matrix metalloproteinase activation are associated with CTC rupture.
    Circulation 11/2008; 118(17):1737-47. · 15.20 Impact Factor
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    ABSTRACT: Morbidity from degenerative aortic valve disease is increasing worldwide, concomitant with the ageing of the general population and the habitual consumption of diets high in calories and cholesterol. Immunohistologic studies have suggested that the molecular mechanism occurring in the degenerate aortic valve resembles that of atherosclerosis, prompting the testing of HMG CoA reductase inhibitors (statins) for the prevention of progression of native and bioprosthetic aortic valve degeneration. However, the effects of these therapies remain controversial. Although the molecular mechanisms underlying the onset of aortic valve degeneration are largely unknown, research in this area is advancing rapidly. The signaling components involved in embryonic valvulogenesis, such as Wnt, TGF-beta(1), BMP, and Notch, are also involved in the onset of aortic valve degeneration. Furthermore, investigations into extracellular matrix remodeling, angiogenesis, and osteogenesis in the aortic valve have been reported. Having noted avascularity of normal cardiac valves, we recently identified chondromodulin-I (chm-I) as a crucial anti-angiogenic factor. The expression of chm-I is restricted to cardiac valves from late embryogenesis to adulthood in the mouse, rat, and human. In human degenerate atherosclerotic valves, the expression of vascular endothelial growth factor (VEGF) and matrix metalloproteinases and angiogenesis is observed in the area of chm-I downregulation. Gene targeting of chm-I resulted in VEGF expression, angiogenesis, and calcification in the aortic valves of aged mice, and aortic stenosis is detected by echocardiography, indicating that chm-I is a crucial factor for maintaining normal cardiac valvular function by preventing angiogenesis. The present review focuses on the animal models of aortic valve degeneration and recent studies on the molecular mechanisms underlying the onset of degenerative aortic valve disease.
    Journal of Molecular Medicine 10/2008; 87(1):17-24. · 4.77 Impact Factor
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    ABSTRACT: Common marmoset monkeys have recently attracted much attention as a primate research model, and are preferred to rhesus and cynomolgus monkeys due to their small bodies, easy handling and efficient breeding. We recently reported the establishment of common marmoset embryonic stem cell (CMESC) lines that could differentiate into three germ layers. Here, we report that our CMESC can also differentiate into cardiomyocytes and investigated their characteristics. After induction, FOG-2 was expressed, followed by GATA4 and Tbx20, then Nkx2.5 and Tbx5. Spontaneous beating could be detected at days 12-15. Immunofluorescent staining and ultrastructural analyses revealed that they possessed characteristics typical of functional cardiomyocytes. They showed sinus node-like action potentials, and the beating rate was augmented by isoproterenol stimulation. The BrdU incorporation assay revealed that CMESC-derived cardiomyocytes retained a high proliferative potential for up to 24 weeks. We believe that CMESC-derived cardiomyocytes will advance preclinical studies in cardiovascular regenerative medicine.
    Biochemical and Biophysical Research Communications 06/2008; 369(3):801-6. · 2.41 Impact Factor
  • Journal of Molecular and Cellular Cardiology - J MOL CELL CARDIOL. 01/2008; 45(4).
  • Journal of Cardiac Failure - J CARD FAIL. 01/2008; 14(7).
  • Journal of Molecular and Cellular Cardiology - J MOL CELL CARDIOL. 01/2008; 45(4).
  • Journal of Cardiac Failure - J CARD FAIL. 01/2008; 14(7).
  • 11/2007: pages 37 - 45; , ISBN: 9780470988909
  • Daihiko Hakuno, Keiichi Fukuda
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    ABSTRACT: Cardiac valves are recognized as avascular tissue as well as cartilage and eye. We recently identified chondromodulin-I as crucial anti-angiogenic factor for maintaining cardiac valvular function. chondromodulin-I was first detected at developmental stage E9.5 in outflow tract, valvular primordium, and left ventricle, but was restricted to cardiac valves from late embryogenesis to adult. In ApoE(-/-) mice and human valvular heart diseases such as atherosclerosis, rheumatic heart diseases, and infective endocarditis, vascular endothelial growth factor (VEGF) and matrix metalloproteinase (MMP) expression and neovascularization were observed in the area of down-regulation of chondromodulin-I. Conditioned medium from cultured-valvular interstitial cells strongly inhibited tube formation and migration of endothelial cells, and these effects were partially blocked by chondromodulin-I siRNA in vitro. Gene targeting of chondromodulin-I caused VEGF expression, neovascularization, lipid deposition, and calcification in cardiac valves of aged mice. Echocardiography showed aortic valve thickening and turbulent flow suggesting early stage of aortic stenosis. These findings provide evidence that chondromodulin-I is a crucial factor for maintaining normal cardiac valvular function by preventing angiogenesis that may lead to valvular heart diseases.
    Clinical calcium 04/2007; 17(3):361-72.
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    ABSTRACT: Bone marrow mesenchymal stem cells (CMG cells) are multipotent and can be induced by 5-azacytidine to differentiate into cardiomyocytes. We characterized the electrophysiological properties of these cardiomyocytes and investigated their potential for use as transplantable bio-pacemakers. After differentiation, action potentials in spontaneously beating cardiomyocytes were initially sinus node-like, but subsequently became ventricular cardiomyocyte-like. RT-PCR established that ion channels mediating I(K1) and I(Kr) were expressed before differentiation. After differentiation, ion channels underlying ICa,L and If were expressed first, followed by ion channels mediating I(to) and I(K,ATP). Differentiated CMG cells expressed beta-adrenergic receptors and increased their beat rate in response to isoproterenol. CMG cardiomyocytes were purified using GFP fluorescence and transplanted into the free walls of the left ventricles of mice. The transplanted cardiomyocytes survived and connected to surrounding recipient cardiomyocytes via intercalated discs. Although further innovation is required, the present findings provide evidence of the potential for bone marrow-derived cardiomyocytes to be used as bio-pacemakers.
    Medical & Biological Engineering & Computing 03/2007; 45(2):209-20. · 1.79 Impact Factor
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    ABSTRACT: Rahul Kakkar and Richard T. Lee – Harvard Medical School, Brigham and Women's Hospital, Cambridge, MA, USA
    Drug Discovery Today Disease Models 01/2007; 4(4):177-184.
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    ABSTRACT: G protein-coupled receptor (GPCR)-evoked signal transduction pathways leading to the activation of extracellular signal-regulated kinases (ERK) are quite different among cell types. In cardiomyocytes, much attention has been focused on the activation of protein kinase C (PKC) or mobilization of intracellular Ca(2+) ([Ca(2+)](i)), however, the contributions of tyrosine kinases are controversial. In the present study, we characterized the signaling pathways involving tyrosine kinases, Pyk2 and epidermal growth factor receptor (EGFR), and their contribution to ERK activation in cultured cardiomyocytes. We initially investigated the potential involvement of [Ca(2+)](i) and PKC on the activation of these kinases in endothelin-stimulated cardiomyocytes. Interestingly, activation of Pyk2 was abrogated by chelating [Ca(2+)](i) or by downregulation of PKC, whereas transactivation of EGFR was solely dependent on PKC. By using a compound that selectively interferes with EGFR (AG1478), c-Src (PP1), or disrupts actin cytoskeleton (cytochalasin D), we demonstrated that cytochalasin D completely inhibited the activation of Pyk2, but not that of EGFR, whereas AG1478 did not inhibit the activation of Pyk2, indicating that transactivation of EGFR and signaling pathways involving Pyk2 were distinct pathways. Furthermore, activation of ERK and Shc, and c- fos gene expression were significantly inhibited by AG1478 but not by cytochalasin D or PP1. Overexpression of deletion mutant of EGFR attenuated the activation of ERK. These facts demonstrated the existence of two distinct tyrosine kinase pathways requiring Pyk2 or EGFR downstream from GPCR in cardiomyocytes. EGFR was Ca(2+)-independently activated and predominantly contributed to Shc/ERK/c- fos activation, while Pyk2 or c-Src contributed less to it.
    Journal of Molecular and Cellular Cardiology 03/2002; 34(2):139-50. · 5.15 Impact Factor
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    ABSTRACT: We recently reported that cardiomyocytes could be differentiated from bone marrow mesenchymal stem cells in vitro by 5-azacytidine treatment. In native cardiomyocytes, adrenergic and muscarinic receptors play crucial roles in mediating heart rate, conduction velocity, contractility, and cardiac hypertrophy. We investigated whether these receptors are expressed in differentiated CMG cells, and if so, whether they have downstream signaling systems. Reverse transcription-polymerase chain reaction revealed that CMG cells had already expressed alpha(1A)-, alpha(1B)-, and alpha(1D)-adrenergic receptor mRNA before 5-azacytidine treatment, whereas expression of beta(1)-, beta(2)-adrenergic and M(1)-, M(2)-muscarinic receptors was first detected at 1 day. Phenylephrine dose-dependently induced phosphorylation of ERK1/2, which was completely inhibited by prazosin, and significantly increased cell size. Isoproterenol augmented cAMP by 38-fold, which was fully inhibited by propranolol. Isoproterenol (10(-7) mol/L) increased the spontaneous beating rate by 47.6% (basal, 127+/-16 bpm), and propranolol and CGP20712A (beta(1)-selective blocker) reduced it by 79.0% and 71.0%, respectively, whereas ICI118551 (beta(2)-selective blocker) induced slight reduction. Cell motion, percent shortening, and contractile velocity were increased by 37.5%, 26.9%, and 50.6%, respectively, in response to isoproterenol. Phenylephrine and isoproterenol augmented ANP and BNP gene expressions. Carbachol increased IP(3) by 32-fold, which was markedly inhibited by atropine as well as AFDX116 (M(2)-selective blocker) measured by radioimmunoassay. These findings indicate that CMG cells expressed alpha(1A), alpha(1B), and alpha(1D) receptors before differentiation and expressed beta(1), beta(2), M(1), and M(2) receptors after they obtained the cardiomyocyte phenotype. These receptors had functional signal transduction pathways and could modulate cell function.
    Circulation 02/2002; 105(3):380-6. · 15.20 Impact Factor
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    ABSTRACT: We recently reported that leukemia inhibitory factor (LIF) enhances Ca(2+)](i) through an increase in L-type Ca(2+) current (I(Ca,L)) in adult cardiomyocytes. The aim of this study was to investigate whether LIF activates Ca(2+)-dependent signaling molecules, such as calcineurin and calmodulin kinases II and IV (CaMKII and CaMKIV), and, if so, whether these Ca(2+)-mediated signaling events contribute to LIF-mediated cardiac hypertrophy. We first confirmed that LIF increased I(Ca,L) and [Ca(2+)](i) in primary cultured rat neonatal cardiomyocytes. Calcineurin, CaMKII, and CaMKIV activities increased at 2 minutes and peaked by 1.6-, 2.2-, and 2.2-fold, respectively, at 15 minutes. Nicardipine or verapamil fully inhibited these activities. Autophosphorylation of CaMKII was also observed to parallel the timing of CaMKII activity, and this phosphorylation was blocked by nicardipine, verapamil, or EGTA. LIF treatment led to a 3-fold increase in nuclear factor of activated T cell-luciferase activity. To confirm that inositol triphosphate (IP(3))-induced Ca(2+) release from sarcoplasmic reticulum was not involved in this process, IP(3) content and phosphorylation of phospholipase Cgamma were investigated. LIF did not increase IP(3) content or phosphorylate phospholipase Cgamma. KN62 (an inhibitor of CaMKII and CaMKIV) attenuated c-fos, brain natriuretic peptide, alpha-skeletal actin, and atrial natriuretic peptide expression. KN62 suppressed the LIF-induced increase in [(3)H]phenylalanine uptake and cell size. Cyclosporin A and FK506 slightly attenuated brain natriuretic peptide but did not affect c-fos or atrial natriuretic peptide expression. Cyclosporin A significantly reduced the LIF-induced increase in [(3)H]phenylalanine uptake. These findings indicated that LIF activated CaMKII, CaMKIV, and calcineurin through an increase in I:(Ca,L) and [Ca(2+)](i) and that CaMKII, CaMKIV, and calcineurin are critically involved in LIF-induced cardiac hypertrophy.
    Circulation Research 12/2000; 87(10):937-45. · 11.86 Impact Factor

Publication Stats

317 Citations
113 Downloads
860 Views
94.46 Total Impact Points

Institutions

  • 2011–2013
    • National Defense Medical College
      • • Department of Internal Medicine
      • • Division of Cardiology
      Tokorozawa, Saitama-ken, Japan
  • 2007–2010
    • Keio University
      • • Department of Cardiology
      • • Institute for Advanced Medical Research
      Edo, Tōkyō, Japan