2025/04/10 更新

写真a

タキヤマ タカオ
滝山 貴央
TAKIYAMA Takao
所属
病院 診療科 内科(内分泌・代謝・膠原病)
外部リンク

学位

  • 医学博士 ( 2022年12月   旭川医科大学 )

  • 医師 ( 2017年3月   旭川医科大学 )

論文

  • A maternal high-fat diet induces fetal origins of NASH-HCC in mice. 国際誌

    Takao Takiyama, Toshihiro Sera, Masanori Nakamura, Masato Hoshino, Kentaro Uesugi, Shin-Ichi Horike, Makiko Meguro-Horike, Ryoichi Bessho, Yuri Takiyama, Hiroya Kitsunai, Yasutaka Takeda, Kazuki Sawamoto, Naoto Yagi, Yuji Nishikawa, Yumi Takiyama

    Scientific reports   12 ( 1 )   13136 - 13136   2022年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Maternal overnutrition affects offspring susceptibility to nonalcoholic steatohepatitis (NASH). Male offspring from high-fat diet (HFD)-fed dams developed a severe form of NASH, leading to highly vascular tumor formation. The cancer/testis antigen HORMA domain containing protein 1 (HORMAD1), one of 146 upregulated differentially expressed genes in fetal livers from HFD-fed dams, was overexpressed with hypoxia-inducible factor 1 alpha (HIF-1alpha) in hepatoblasts and in NASH-based hepatocellular carcinoma (HCC) in offspring from HFD-fed dams at 15 weeks old. Hypoxia substantially increased Hormad1 expression in primary mouse hepatocytes. Despite the presence of three putative hypoxia response elements within the mouse Hormad1 gene, the Hif-1alpha siRNA only slightly decreased hypoxia-induced Hormad1 mRNA expression. In contrast, N-acetylcysteine, but not rotenone, inhibited hypoxia-induced Hormad1 expression, indicating its dependency on nonmitochondrial reactive oxygen species production. Synchrotron-based phase-contrast micro-CT of the fetuses from HFD-fed dams showed significant enlargement of the liver accompanied by a consistent size of the umbilical vein, which may cause hypoxia in the fetal liver. Based on these findings, a maternal HFD induces fetal origins of NASH/HCC via hypoxia, and HORMAD1 is a potential therapeutic target for NASH/HCC.

    DOI: 10.1038/s41598-022-17501-8

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  • A case of insulinoma diagnosed postpartum with hypoglycemic symptoms that were masked during pregnancy. 国際誌

    Tomoe Abe, Yasutaka Takeda, Takao Takiyama, Ayaka Sasaki, Ryoichi Bessho, Mao Sato, Hiroya Kitsunai, Hidemitsu Sakagami, Atsuko Abiko, Koji Imai, Sayaka Yuzawa, Mishie Tanino, Yumi Takiyama

    Clinical case reports   9 ( 4 )   1991 - 1998   2021年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The diagnosis of insulinoma in perinatal women can be difficult, as hypoglycemic symptoms may be masked by pregnancy-associated insulin resistance. In addition, when multiple insulinomas are observed, it is necessary to consider the possibility not only of MEN1, but also of insulinomatosis.

    DOI: 10.1002/ccr3.3924

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  • Hypoxia-inducible factor-1α is the therapeutic target of the SGLT2 inhibitor for diabetic nephropathy. 国際誌

    Ryoichi Bessho, Yumi Takiyama, Takao Takiyama, Hiroya Kitsunai, Yasutaka Takeda, Hidemitsu Sakagami, Tsuguhito Ota

    Scientific reports   9 ( 1 )   14754 - 14754   2019年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Previous studies have demonstrated intrarenal hypoxia in patients with diabetes. Hypoxia-inducible factor (HIF)-1 plays an important role in hypoxia-induced tubulointerstitial fibrosis. Recent clinical trials have confirmed the renoprotective action of SGLT2 inhibitors in diabetic nephropathy. We explored the effects of an SGLT2 inhibitor, luseogliflozin on HIF-1α expression in human renal proximal tubular epithelial cells (HRPTECs). Luseogliflozin significantly inhibited hypoxia-induced HIF-1α protein expression in HRPTECs. In addition, luseogliflozin inhibited hypoxia-induced the expression of the HIF-1α target genes PAI-1, VEGF, GLUT1, HK2 and PKM. Although luseogliflozin increased phosphorylated-AMP-activated protein kinase α (p-AMPKα) levels, the AMPK activator AICAR did not changed hypoxia-induced HIF-1α expression. Luseogliflozin suppressed the oxygen consumption rate in HRPTECs, and subsequently decreased hypoxia-sensitive dye, pimonidazole staining under hypoxia, suggesting that luseogliflozin promoted the degradation of HIF-1α protein by redistribution of intracellular oxygen. To confirm the inhibitory effect of luseogliflozin on hypoxia-induced HIF-1α protein in vivo, we treated male diabetic db/db mice with luseogliflozin for 8 to 16 weeks. Luseogliflozin attenuated cortical tubular HIF-1α expression, tubular injury and interstitial fibronectin in db/db mice. Together, luseogliflozin inhibits hypoxia-induced HIF-1α accumulation by suppressing mitochondrial oxygen consumption. The SGLT2 inhibitors may protect diabetic kidneys by therapeutically targeting HIF-1α protein.

    DOI: 10.1038/s41598-019-51343-1

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  • Impacts of Diabetes and an SGLT2 Inhibitor on the Glomerular Number and Volume in db/db Mice, as Estimated by Synchrotron Radiation Micro-CT at SPring-8. 国際誌

    Yumi Takiyama, Toshihiro Sera, Masanori Nakamura, Kanaki Ishizeki, Yasuaki Saijo, Tsuyoshi Yanagimachi, Manami Maeda, Ryoichi Bessho, Takao Takiyama, Hiroya Kitsunai, Hidemitsu Sakagami, Daisuke Fujishiro, Yukihiro Fujita, Yuichi Makino, Atsuko Abiko, Masato Hoshino, Kentaro Uesugi, Naoto Yagi, Tsuguhito Ota, Masakazu Haneda

    EBioMedicine   36   329 - 346   2018年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    BACKGROUND: Recent large-scale clinical studies demonstrate that sodium-glucose cotransporter 2 (SGLT2) inhibitors protect the diabetic kidney. However, clinical and animal studies have not shown the changes of the total glomeruli in the whole kidney treated with SGLT2 inhibitors. METHODS: We performed computed tomography (CT) imaging on mice using synchrotron radiation to investigate the impact of luseogliflozin, a SGLT2 inhibitor, on the number and volume of glomeruli in the whole kidney. FINDINGS: We did not observe a significant difference in the total glomerular number (Nglom) among mice. Luseogliflozin redistributed the number of glomeruli in different regions, accompanied by the normalization of diabetes-augmented renal volume (Vkidney). Diabetic db/db mice had a larger glomerular volume in the mid-cortex than did control db/m mice, and luseogliflozin increased the glomerular volume in all renal cortical zones of the whole kidney in db/db mice. According to the multivariate regression analysis, hemoglobin A1c level was the most relevant determinant of Vkidney, not Nglom or mean glomerular volume (Vglom), indicating that hyperglycemia induced renal (tubular) hypertrophy, but not glomerular enlargement. Luseogliflozin increased hypoxia in the juxtamedullary region, sustained upregulated renal renin expression and plasma renin activity, and failed to decrease albuminuria by downregulating megalin in db/db mice. INTERPRETATION: Based on our findings, SGLT2 inhibitors may alter glomerular distribution and size in addition to their glucose-lowering effects, presumably by affecting oxygen metabolism and humoral factors. FUND: Funding for this research was provided by The Japan Society for the Promotion of Science, the Japan Diabetes Foundation, and Asahikawa Medical University.

    DOI: 10.1016/j.ebiom.2018.09.048

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