Kazuhiro Takekoshi

University of Tsukuba, Tsukuba, Ibaraki, Japan

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Publications (77)201.29 Total impact

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    ABSTRACT: Transcriptional regulation of metabolic genes in the liver is the key to maintaining systemic energy homeostasis during starvation. The membrane-bound transcription factor cAMP-responsive element-binding protein 3-like 3 (CREB3L3) has been reported to be activated during fasting and to regulate triglyceride metabolism. Here, we show that CREB3L3 confers a wide spectrum of metabolic responses to starvation in vivo. Adenoviral and transgenic overexpression of nuclear CREB3L3 induced systemic lipolysis, hepatic ketogenesis, and insulin sensitivity with increased energy expenditure, leading to marked reduction in body weight, plasma lipid levels, and glucose levels. CREB3L3 overexpression activated gene expression levels and plasma levels of antidiabetic hormones, including fibroblast growth factor 21 and IGF-binding protein 2. Amelioration of diabetes by hepatic activation of CREB3L3 was also observed in several types of diabetic obese mice. Nuclear CREB3L3 mutually activates the peroxisome proliferator-activated receptor α promoter in an autoloop fashion and is crucial for the ligand transactivation of peroxisome proliferator-activated receptor α by interacting with its transcriptional regulator, PGC-1α. CREB3L3 directly and indirectly controls fibroblast growth factor 21 expression and its plasma level, which contributes at least partially to the catabolic effects of CREB3L3 on systemic energy homeostasis in the entire body. Therefore, CREB3L3 is a therapeutic target for obesity and diabetes.
    Endocrinology 09/2014; 155(12):en20141113. DOI:10.1210/en.2014-1113 · 4.72 Impact Factor
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    ABSTRACT: Measuring the levels of the plasma free metanephrines (PFMs) represents a recently developed and promising test for the diagnosis of pheochromocytoma in the United States and Europe. As this test has not yet been evaluated in Japan, it is necessary to evaluate the diagnostic efficacy of measuring the levels of PFMs compared with the standard measurement of the urinary excretion of metanephrines (uMNs) whose reliability is well established to detect of pheochromocytoma. A total of 101 Japanese subjects clinically suspected of having pheochromocytoma in were included in this study. Subsequently, we prospectively measured the PFMs levels in all patients, compared with those of biochemical markers of the catecholamine secretion and metabolisms in the plasma and urine. All subjects with adrenal tumors underwent tumor excision. Data were available for 84 of the 101 patients, 47 of whom had histopathologically proven pheochromocytoma and 37 were finally diagnosed with non-pheochromocytoma. The results of comparisons in the accuracy of measurement for diagnosis of pheochromocytoma between PFMs and the urinary excretion of metanephrines (uMNs) were 0.980 VS 0.951 for AUC of receiver operatorating characteristic (ROC) curve, 0.957 VS 0.894 for sensitivity, and 0.973 VS 0.946 for specificity, respectively. Although the differences were small, the results of our study definitely demonstrated that measurement of PFMs was not inferior to standard urinary metanephrines (uMNs) measurement, which is established to be the most reliable biochemical method to detect pheochromocytoma. This study clearly shows measuring the PFMs levels to be a reliable and efficient method for diagnosing pheochromocytoma in Japanese patients, as demonstrated in previous reports.
    Endocrine Journal 05/2014; DOI:10.1507/endocrj.EJ13-0277 · 2.02 Impact Factor
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    ABSTRACT: Dear Editor,Pheochromocytoma (PCC) and paraganglioma (PGL) are genetically and phenotypically heterogeneous catecholamine producing neoplasms. They can occur sporadically or as a part of hereditary disease. Approximately 30% of PCC /PGL are believed to be caused by germline mutations (Welander et al. 2011). Of these, succinate dehydrogenase subunit B (SDHB) gene mutation is considered a high-risk factor for malignancy. Loss of heterozygosity at the SDHB locus (1p36) was observed in all tumors with SDHB mutation, and Gimenez-Roqueplo et al. (2003) strongly suggested that SDHB is a tumor suppressor gene. Subsequently, loss of SDHB protein immunoreactivity in SDHB-mutated PCC/PGL (SDHB-PCC/PGL) was reported with 100% sensitivity and 84% specificity (van Nederveen et al. 2009). Thus, SDHB immunohistochemistry can be used to screen SDHB-PCC/PGL using paraffin-embedded pathological materials. SDHB mutation is the only established factor that indicates future metastasis. Therefore, it is important to analyze the histological characteristics of SDHB-PCC/PGL.It is generally accepted that it is difficult to distinguish histological differences between benign and malignant PCC/ PGL. The current consensus is that a long-term follow-up is required after the surgery to screen for recurrence or metastasis in all PCC/PGL patients, regardless whether hereditary or sporadic in origin. Kimura et al. (2014) proposed a histological grading system called the GAPP (Grading of Adrenal Pheochromocytoma and Paraganglioma) classification for predicting metastasis. GAPP is composed of six factors: histological pattern, cellularity, presence or absence of comedo-type necrosis, vascular or capsular invasion, Ki67 labeling index (%), and elevated catecholamine type. Each factor was assigned a point and the number of points was summated.
    Endocrine Related Cancer 03/2014; DOI:10.1530/ERC-13-0530 · 5.26 Impact Factor
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    ABSTRACT: It is insufficient to distinguish benign tumors from malignant pheochromocytoma using histological analyses of resected tissue alone. We experienced an 18-year-old woman who complained of severe headaches in whom hypertension was revealed. She was suspected of having a malignant tumor based on her clinical characteristics, despite showing no evidence of metastatic lesions. The patient was diagnosed with an aggressive form of hereditary pheochromocytoma-paraganglioma syndrome (HPPS) based on immunohistochemical analyses and genetic testing. The present case indicates that conducting genetic testing, including SDHB mutation analyses, is required to determine the prognosis in patients highly suspected of having HPPS.
    Internal Medicine 01/2013; 52(2):281-4. DOI:10.2169/internalmedicine.52.8223 · 0.97 Impact Factor
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    ABSTRACT: Sunitinib is an oral multitargeted receptor tyrosine kinase inhibitor with antiangiogenic and antitumor activity that mainly targets vascular endothelial growth factor receptors, and recently, it has been shown to be an active agent for the treatment of malignant pheochromocytomas. Previously, we demonstrated that sunitinib directly inhibited mTORC1 signaling in rat pheochromocytoma PC12 cells. Although autophagy is a highly regulated cellular process, its relevance to cancer seems to be complicated. It is of note that inhibition of mTORC1 is a prerequisite for autophagy induction. Indeed, direct mTORC1 inhibition initiates ULK1/2 autophosphorylation and subsequent Atg13 and FIP200 phosphorylation, inducing autophagy. Here, we demonstrated that sunitinib significantly increased the levels of LC3-II, concomitant with a decrease of p62 in PC12 cells. Following sunitinib treatment, immunofluorescent imaging revealed a marked increased punctate LC3-II distribution. Furthermore, Atg13 knockdown significantly reduced its protein level, which in turn abolished sunitinib-induced autophagy. Moreover, inhibition of autophagy by siRNAs targeting Atg13 or by pharmacological inhibition with ammonium chloride, enhanced both sunitinib-induced apoptosis and anti-proliferation. Thus, sunitinib-induced autophagy is dependent on the suppression of mTORC1 signaling and the formation of ULK1/2-Atg13-FIP200 complexes. Inhibition of autophagy may be a promising therapeutic option for improving the anti-tumor effect of sunitinib.
    Journal of Pharmacological Sciences 12/2012; 121(1). DOI:10.1254/jphs.12158FP · 2.11 Impact Factor
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    ABSTRACT: Sunitinib is an oral, small molecule multitargeted receptor tyrosine kinase inhibitor with antiangiogenic and antitumor activity that primarily targets vascular endothelial growth factor receptors (VEGFRs). Although sunitinib is an active agent for the treatment of malignant pheochromocytomas, it is unclear whether sunitinib acts through only antiangiogenic mechanisms or also directly targets tumor cells. We previously showed that sunitinib directly induced apoptosis of PC-12 cells. To further confirm these direct effects, we examined the effects of sunitinib on tyrosine hydroxylase (TH) (the rate-limiting enzyme in catecholamine biosynthesis) activity and catecholamine secretion in PC-12 cells and the underlying mechanisms. Sunitinib inhibited TH activity in a dose-dependent manner, and decreased TH protein levels. Consistent with this finding, sunitinib decreased TH phosphorylation at Ser(31) and Ser(40) and significantly decreased catecholamine secretion. VEGFR-2 knockdown attenuated these effects, including inhibition of TH activity and catecholamine secretion, suggesting that they were mediated by VEGFR-2. Sunitinib significantly decreased phospholipase C (PLC)-γ phosphorylation and subsequent protein kinase C (PKC) activity. Because Ser(40) phosphorylation significantly affects TH activity and is known to be regulated by PKC, sunitinib may inhibit Ser(40) phosphorylation via the VEGFR-2/PLC-γ/PKC pathway. Additionally, sunitinib markedly decreased the activity of extracellular signal-regulated kinase (ERK), but not c-Jun NH(2)-terminal kinase or p38 mitogen-activated protein kinase. Therefore, sunitinib may reduce TH Ser(31) phosphorylation through inhibition of the VEGFR-2/PLC-γ/PKC/Raf/mitogen-activated protein kinase/extracellular signal-regulated kinase kinase/ERK pathway. Sunitinib also significantly reduced inositol 1,4,5-trisphosphate production. However, because PC-12 cells do not precisely reflect the pathogenesis of malignant cells, we confirmed the key findings in a human neuroblastoma cell line, SK-N-SH. In conclusion, sunitinib directly inhibits catecholamine synthesis and secretion in pheochromocytoma PC-12 cells.
    AJP Endocrinology and Metabolism 08/2012; 303(8):E1006-14. DOI:10.1152/ajpendo.00156.2012 · 4.51 Impact Factor
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    ABSTRACT: Nonalcoholic steatohepatitis (NASH) is associated with obesity and type 2 diabetes, and increase the potential for liver cirrhosis and cancer. ELOVL family member 6, elongation of very long chain fatty acids (Elovl6) is a microsomal enzyme, which regulates the elongation of C12-16 saturated and monounsaturated fatty acids (FAs). We have shown previously that Elovl6 is a major target for sterol regulatory element binding proteins (SREBPs) in the liver, and that it plays a critical role in development of obesity-induced insulin resistance by modifying FA composition. To further investigate role of Elovl6 in development of NASH and its underlying machanism, we utilized three independent mouse models with loss or gain of function of Elovl6, and human liver samples isolated from patients with NASH in this study. Our results demonstrated that 1) Elovl6 is a critical modulator for atherogenic high-fat (AHF) diet-induced inflammation, oxidative stress, and fibrosis in the liver, that 2) Elovl6 expression is positively correlated with severity of hepatosteatosis and liver injury in NASH patients, and that 3) deletion of Elovl6 reduces palmitate-induced activation of the NLR family pyrin domain containing 3 (NLRP3) inflammasome; this could be at least one of the underlying mechanisms, by which Elovl6 modulates a progress of NASH. In conclusion, Hepatic long-chain fatty acid composition is a novel determinant in NASH development, and Elovl6 could be a potential therapeutic target for prevention and treatment of NASH. (HEPATOLOGY 2012.).
    Hepatology 06/2012; 56(6). DOI:10.1002/hep.25932 · 11.19 Impact Factor
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    ABSTRACT: Recently, TMEM127 was shown to be a new pheochromocytoma susceptibility gene; this is consistent with its function as a tumour suppressor gene (Journal of Clinical Endocrinology and Metabolism, 2009, 94, 2817). Most pheochromocytomas arise from the adrenal medulla, and in approximately half of the cases, the tumours are bilateral (Journal of Clinical Endocrinology and Metabolism, 2009, 94, 2817; Journal of the American Medical Association, 2004, 292, 943; Human Mutation, 2010, 31, 41; Science, 2009, 325, 1139). The aim of the present study was to determine whether TMEM127 mutations are involved in the pathogenesis of pheochromocytomas/paragangliomas in Japanese subjects. For this study, 74 unrelated patients with pheochromocytoma/paraganglioma who tested negative for mutations and deletions in RET, VHL, SDHB and SDHD were recruited through a multi-institutional collaborative effort in Japan. The TMEM127 gene sequence was determined in their germline DNA, and tumour DNA was analysed for the loss of heterozygosity. In addition, their TMEM127 gene sequences were compared with sequences from 114 normal healthy, ethnically matched controls. Among the 74 eligible patients, two unrelated patients (2·7%) with bilateral adrenal pheochromocytoma were found to have an identical germline TMEM127 mutation (c.116_119delTGTC, p.Ile41ArgfsX39) associated with 2q deletion loss of heterozygosity, which was also previously described in a Brazilian case (Journal of the American Medical Association, 2004, 292, 943). We also determined that none of the 114 normal healthy controls had this deletion mutation. This is the first report showing that TMEM127 mutation plays a pathological role in pheochromocytoma in an Asian population. Although our surveillance is limited, the prevalence and the phenotype of this gene mutation appear to be similar to those reported in previous studies.
    Clinical Endocrinology 04/2012; 77(5):707-14. DOI:10.1111/j.1365-2265.2012.04421.x · 3.35 Impact Factor
  • Kazuhiro Takekoshi, Yasushi Kawakami
    Nihon Naika Gakkai Zasshi 04/2012; 101(4):949-58. DOI:10.2169/naika.101.949
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    ABSTRACT: F-box and WD repeat domain-containing 7α (Fbw7α) is the substrate recognition component of a ubiquitin ligase that controls the degradation of factors involved in cellular growth, including c-Myc, cyclin E, and c-Jun. In addition, Fbw7α degrades the nuclear form of sterol regulatory element-binding protein (SREBP)-1a, a global regulator of lipid synthesis, particularly during mitosis in cultured cells. This study investigated the in vivo role of Fbw7α in hepatic lipid metabolism. siRNA knockdown of Fbw7α in mice caused marked hepatosteatosis with the accumulation of triglycerides. However, inhibition of Fbw7α did not change the level of nuclear SREBP-1 protein or the expression of genes involved in fatty acid synthesis and oxidation. In vivo experiments on the gain and loss of Fbw7α function indicated that Fbw7α regulated the expression of peroxisome proliferator-activated receptor (PPAR) γ2 and its target genes involved in fatty acid uptake and triglyceride synthesis. These genes included fatty acid transporter Cd36, diacylglycerol acyltransferase 1 (Dgat1), and fat-specific protein 27 (Cidec). The regulation of PPARγ2 by Fbw7α was mediated, at least in part, by the direct degradation of the Krüppel-like factor 5 (KLF5) protein, upstream of PPARγ2 expression. Hepatic Fbw7α contributes to normal fatty acid and triglyceride metabolism, functions that represent novel aspects of this cell growth regulator.
    Journal of Biological Chemistry 11/2011; 286(47):40835-40846. · 4.60 Impact Factor
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    ABSTRACT: F-box and WD repeat domain-containing 7α (Fbw7α) is the substrate recognition component of a ubiquitin ligase that controls the degradation of factors involved in cellular growth, including c-Myc, cyclin E, and c-Jun. In addition, Fbw7α degrades the nuclear form of sterol regulatory element-binding protein (SREBP)-1a, a global regulator of lipid synthesis, particularly during mitosis in cultured cells. This study investigated the in vivo role of Fbw7α in hepatic lipid metabolism. siRNA knockdown of Fbw7α in mice caused marked hepatosteatosis with the accumulation of triglycerides. However, inhibition of Fbw7α did not change the level of nuclear SREBP-1 protein or the expression of genes involved in fatty acid synthesis and oxidation. In vivo experiments on the gain and loss of Fbw7α function indicated that Fbw7α regulated the expression of peroxisome proliferator-activated receptor (PPAR) γ2 and its target genes involved in fatty acid uptake and triglyceride synthesis. These genes included fatty acid transporter Cd36, diacylglycerol acyltransferase 1 (Dgat1), and fat-specific protein 27 (Cidec). The regulation of PPARγ2 by Fbw7α was mediated, at least in part, by the direct degradation of the Krüppel-like factor 5 (KLF5) protein, upstream of PPARγ2 expression. Hepatic Fbw7α contributes to normal fatty acid and triglyceride metabolism, functions that represent novel aspects of this cell growth regulator.
    Journal of Biological Chemistry 09/2011; 286(47):40835-46. DOI:10.1074/jbc.M111.235283 · 4.60 Impact Factor
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    ABSTRACT: Sunitinib is an oral multitargeted receptor tyrosine kinase inhibitor with antiangiogenic and antitumor activity that mainly targets vascular endothelial growth factor receptors (VEGFRs). Very recently, sunitinib has been shown to be an active agent for the treatment of malignant pheochromocytomas. However, it is unclear whether sunitinib acts only through an antiangiogenic mechanism or whether it may also directly target tumor cells. Sunitinib markedly induced apoptosis of PC12 cells in a dose-dependent and time-dependent manner. Furthermore, in support of these findings, we found that sunitinib induced a reduction in the expression of the antiapoptotic molecule Bcl-2 as well as dephosphorylation of the proapoptotic molecule BAD, which results in the activation of BAD in these cells. Consistent with these apoptotic effects, our results showed that sunitinib inhibited phosphorylation of Akt and mTOR and was followed by a reduction of S6K1, which is a well-known target of mTOR. Knockdown of VEGFR-2 attenuated the sunitinib-induced effects, including apoptosis and inhibition of signaling pathways such as the phosphorylation of Akt as well as mTOR, and Bcl-2, which confirmed that these effects could be mediated by VEGFR-2. In addition, silencing of S6K1 induced apoptosis accompanied by a decrease in the phosphorylation of BAD and Bcl-2, similar to that observed with sunitinib treatment. Thus, these results together suggest that sunitinib initially exerts its apoptotic effect through the inhibition of VEGFR-2, which, when followed by reduction of its downstream effectors, including Akt/mTOR/S6K1, may lead to inhibition of the antiapoptotic molecule Bcl-2 and activation of the proapoptotic molecule BAD in PC12 cells. However, PC12 cells do not precisely reflect the pathogenesis of malignant cells. Therefore, we confirmed the key findings by replicating these experiments in human neuroblastoma SK-N-SH cells.
    AJP Endocrinology and Metabolism 08/2011; 302(6):E615-25. DOI:10.1152/ajpendo.00035.2011 · 4.51 Impact Factor
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    ABSTRACT: Sterol regulatory element-binding protein-1 (SREBP-1) is nutritionally regulated and is known to be a key transcription factor regulating lipogenic enzymes. The goal of this study was to evaluate the roles of SREBP-1 in dyslipidemia and atherosclerosis. Transgenic mice that overexpress SREBP-1c in the liver and SREBP-1-deficient mice were crossed with low-density lipoprotein receptor (LDLR)-deficient mice, and the plasma lipids and atherosclerosis were analyzed. Hepatic SREBP-1c overexpression in LDLR-deficient mice caused postprandial hypertriglyceridemia, increased very-low-density lipoprotein (VLDL) cholesterol, and decreased high-density lipoprotein cholesterol in plasma, which resulted in accelerated aortic atheroma formation. Conversely, absence of SREBP-1 suppressed Western diet-induced hyperlipidemia in LDLR-deficient mice and ameliorated atherosclerosis. In contrast, bone marrow-specific SREBP-1 deficiency did not alter the development of atherosclerosis. The size of nascent VLDL particles secreted from the liver was increased in SREBP-1c transgenic mice and reduced in SREBP-1-deficient mice, accompanied by upregulation and downregulation of phospholipid transfer protein expression, respectively. Hepatic SREBP-1c determines plasma triglycerides and remnant cholesterol and contributes to atherosclerosis in hyperlipidemic states. Hepatic SREBP-1c also regulates the size of nascent VLDL particles.
    Arteriosclerosis Thrombosis and Vascular Biology 05/2011; 31(8):1788-95. DOI:10.1161/ATVBAHA.110.219659 · 6.34 Impact Factor
  • Kazuhiro Takekoshi, Kazumasa Isobe, Yasushi Kawakami
    Nippon rinsho. Japanese journal of clinical medicine 03/2011; 69 Suppl 2:511-4.
  • Kazuhiro Takekoshi
    Nippon rinsho. Japanese journal of clinical medicine 07/2010; 68 Suppl 7:256-9.
  • Kazuhiro Takekoshi
    Nippon rinsho. Japanese journal of clinical medicine 07/2010; 68 Suppl 7:429-32.
  • Kazuhiro Takekoshi, Toshiaki Nakai
    Nippon rinsho. Japanese journal of clinical medicine 07/2010; 68 Suppl 7:213-5.
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    ABSTRACT: Recently, mutations in nuclear genes encoding two mitochondrial complex II subunit proteins, Succinate dehydrogenase D (SDHD) and SDHB, have been found to be associated with the development of familial pheochromocytomas and paragangliomas (hereditary pheochromocytoma/paraganglioma syndrome: HPPS). Growing evidence suggests that the mutation of SDHB is highly associated with abdominal paraganglioma and the following distant metastasis (malignant paraganglioma). In the present study, we used multiplex ligation dependent probe amplification (MLPA) analysis to identify a large heterozygous SDHB gene deletion encompassing sequences corresponding to the promoter region, in addition to exon 1 and exon 2 malignant paraganglioma patient in whom previously characterized SDHB mutations were undetectable. This is the first Japanese case report of malignant paraganglioma, with a large SDHB deletions. Our present findings strongly support the notion that large deletions in the SDHB gene should be considered in patients lacking characterized SDHB mutations.
    Endocrine Journal 04/2010; 57(4):351-6. DOI:10.1507/endocrj.K09E-324 · 2.02 Impact Factor
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    ABSTRACT: Urotensin II (U-II), initially identified as a cyclic peptide from fish urophysis, acts both as a strong vasoconstrictor and vasodilator in the vasculature via its receptor, G-protein coupled receptor 14. In addition, U-II and its receptor are co-expressed in the adrenal medulla, as well as in human pheochromocytomas, suggesting that this peptide may have some function in chromaffin cells. However, the precise role of U-II in these cells is unknown. In the present study, we initially demonstrate that U-II and its receptors mRNA are co-expressed in the rat pheochromocytoma cell line PC12. Moreover, U-II has not effect on tyrosine hydroxylase (TH), the rate-limiting enzyme involved in the biosynthesis of catecholamine, in terms of enzyme activity or at the mRNA level. However, U-II does induce an increase in the phosphorylation of TH specifically at Ser31 without affecting phosphorylation at the two other sites (Ser19 and Ser40). U-II also markedly activates extracellular signal-regulated kinases (ERKs) and p38, but not Jun N-terminal kinase. Blockade of the epidermal growth factor (EGF) receptor by AG1478 significantly reduces activation of ERK, suggesting that EGF receptor transactivation could act upstream of the ERK pathway in PC12 cells. Furthermore, U-II significantly increases dopamine secretion from PC12 cells. Finally, we show that U-II induced significant DNA synthesis in a ERKs and P38 mitogen-activated protein kinase-dependent manner. The results obtained indicate that U-II may exert its effects as a neuromodulator in chromaffin cells.
    Journal of Neuroendocrinology 12/2009; 22(2):83-91. DOI:10.1111/j.1365-2826.2009.01944.x · 3.51 Impact Factor

Publication Stats

776 Citations
201.29 Total Impact Points

Institutions

  • 1995–2012
    • University of Tsukuba
      • Institute of Clinical Medicine
      Tsukuba, Ibaraki, Japan
  • 2010
    • Tokyo Women's Medical University
      Edo, Tōkyō, Japan
  • 2009
    • Kansai Medical University
      • Department of Thoracic and Cardiovascular Surgery
      Moriguchi, Osaka-fu, Japan
  • 1993–1994
    • Dokkyo Medical University
      • Department of Endocrinology and Metabolism
      Totigi, Tochigi, Japan