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Ando, Hitoshi ; Takamura, Toshinari ; Matsuzawa-Nagata, Naoto ; Shima, Kosuke R. ; Nakamura, Seiji ; Kumazaki, Masafumi ; Kurita, Seiichiro ; Misu, Hirofumi ; Togawa, Naoyuki ; Fukushima, Tatsunobu ; Fujimura, Akio ; Kaneko, Shuichi
概要:
金沢大学医薬保健研究域医学系<br />Recent studies have correlated metabolic diseases, such as metabolic syndrome and non-alcoholic fatt
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y liver disease, with the circadian clock. However, whether such metabolic changes per se affect the circadian clock remains controversial. To address this, we investigated the daily mRNA expression profiles of clock genes in the liver of a dietary mouse model of non-alcoholic steatohepatitis (NASH) using a custom-made, high-precision DNA chip. C57BL/6J mice fed an atherogenic diet for 5 weeks developed hypercholesterolemia, oxidative stress, and NASH. DNA chip analyses revealed that the atherogenic diet had a great influence on the mRNA expression of a wide range of genes linked to mitochondrial energy production, redox regulation, and carbohydrate and lipid metabolism. However, the rhythmic mRNA expression of the clock genes in the liver remained intact. Most of the circadianly expressed genes also showed 24-h rhythmicity. These findings suggest that the biological clock is protected against such a metabolic derangement as NASH. © 2009 Elsevier Inc. All rights reserved.
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Ando, Hitoshi ; Oshima, Yasuo ; Yanagihara, Hayato ; Hayashi, Yohei ; Takamura, Toshinari ; Kaneko, Shuichi ; Fujimura, Akio
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金沢大学大学院医学系研究科環境社会医学<br />Although a number of genes expressed in most tissues, including the liver, exhibit circadian re
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gulation, gene expression profiles are usually examined only at one scheduled time each day. In this study, we investigated the effects of obese diabetes on the hepatic mRNA levels of various genes at 6-h intervals over a single 24-h period. Microarray analysis revealed that many genes are expressed rhythmically, not only in control KK mice but also in obese diabetic KK-Ay mice. Real-time quantitative PCR verified that 19 of 23 putative circadianly expressed genes showed significant 24-h rhythmicity in both strains. However, obese diabetes attenuated these expression rhythms in 10 of 19 genes. More importantly, the effects of obese diabetes were observed throughout the day in only two genes. These results suggest that observation time influences the results of gene expression analyses of genes expressed circadianly. © 2006 Elsevier Inc. All rights reserved.
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Ando, Hitoshi ; Kurita, Seiichiro ; Shimizu, Akiko ; Kato, Ken-ichiro ; Ishikura, Kazuhide ; Taji, Koumei ; Uno, Masafumi ; Takeshita, Yumie ; Misu, Hirofumi ; Fujimura, Akio ; Kaneko, Shuichi ; Takamura, Toshinari
概要:
Few studies have evaluated the pharmacokinetics of rapid-acting insulin analogues in patients with Type 2 diabetes, espe
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cially under clinical conditions. The aim of the present study was to assess both the pharmacokinetics and pharmacodynamics of insulin aspart in Type 2 diabetic patients who were being treated with the analogue alone. Meal tolerance tests with and without self-injection of a customary dose of insulin aspart (0.05-0.22 U/kg) were conducted in 20 patients in a randomized cross-over study. The dose of insulin aspart (per bodyweight) was significantly correlated with both the maximum concentration (r 2 = 0.59; P < 0.01) and area under the concentration-time curve for insulin aspart (r 2 = 0.53; P < 0.01). However, the time to maximum concentration (T max), which varied widely from < 60 to ≥ 120 min, was not associated with either dosage (r 2 = 0.02; P = 0.51) or body mass index (r 2 = 0.02; P = 0.57). Injection of insulin aspart exacerbated delayed hyperinsulinaemia after meal loading, mainly in patients with T max ≥ 120 min. With regard to pharmacodynamics, insulin aspart had favourable effects on postprandial hyperglycaemia, hyperglucagonaemia and hyperlipidaemia. The T max for this insulin analogue differed greatly between individuals and delayed hyperinsulinaemia was particularly exacerbated in patients with higher T max values. Identification of the factors contributing to interindividual variation in the absorption lag time is essential for improving the efficacy and safety of insulin aspart. © 2012 The Authors. Clinical and Experimental Pharmacology and Physiology © 2012 Blackwell Publishing Asia Pty Ltd.
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| 4.
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Kita, Yuki ; Takamura, Toshinari ; Misu, Hirofumi ; Ota, Tsuguhito ; Kurita, Seiichiro ; Takeshita, Yumie ; Uno, Masafumi ; Matsuzawa-Nagata, Naoto ; Kato, Ken-ichiro ; Ando, Hitoshi ; Fujimura, Akio ; Hayashi, Koji ; Kimura, Toru ; Ni, Yinhua ; Otoda, Toshiki ; Miyamoto, Ken-ichi ; Zen, Yoh ; Nakanuma, Yasuni ; Kaneko, Shuichi
概要:
Background: Optimal treatment for nonalcoholic steatohepatitis (NASH) has not yet been established, particularly for ind
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ividuals without diabetes. We examined the effects of metformin, commonly used to treat patients with type 2 diabetes, on liver pathology in a non-diabetic NASH mouse model. Methodology/Principal Findings: Eight-week-old C57BL/6 mice were fed a methionine- and choline-deficient plus high fat (MCD+HF) diet with or without 0.1% metformin for 8 weeks. Co-administration of metformin significantly decreased fasting plasma glucose levels, but did not affect glucose tolerance or peripheral insulin sensitivity. Metformin ameliorated MCD+HF diet-induced hepatic steatosis, inflammation, and fibrosis. Furthermore, metformin significantly reversed hepatic steatosis and inflammation when administered after the development of experimental NASH. Conclusions/Significance: These histological changes were accompanied by reduced hepatic triglyceride content, suppressed hepatic stellate cell activation, and the downregulation of genes involved in fatty acid metabolism, inflammation, and fibrogenesis. Metformin prevented and reversed steatosis and inflammation of NASH in an experimental non-diabetic model without affecting peripheral insulin resistance. © 2012 Kita et al.
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Ishikura, Kazuhide ; Misu, Hirofumi ; Kumazaki, Masafumi ; Takayama, Hiroaki ; Matsuzawa-Nagata, Naoto ; Tajima, Natsumi ; Chikamoto, Keita ; Lan, Fei ; Ando, Hitoshi ; Ota, Tsuguhito ; Sakurai, Masaru ; Takeshita, Yumie ; Kato, Kenichiro ; Fujimura, Akio ; Miyamoto, Ken-ichi ; Saito, Yoshiro ; Kameo, Satomi ; Okamoto, Yasuo ; Takuwa, Yoh ; Takahashi, Kazuhiko ; Kidoya, Hiroyasu ; Takakura, Nobuyuki ; Kaneko, Shuichi ; Takamaura, Toshinari
概要:
Aims/hypothesis Impaired angiogenesis induced by vascular endothelial growth factor (VEGF) resistance is a hallmark of v
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ascular complications in type 2 diabetes; however, its molecular mechanism is not fully understood. We have previously identified selenoprotein P (SeP, encoded by the SEPP1 gene in humans) as a liver-derived secretory protein that induces insulin resistance. Levels of serum SeP and hepatic expression of SEPP1 are elevated in type 2 diabetes. Here, we investigated the effects of SeP on VEGF signalling and angiogenesis. Methods We assessed the action of glucose on Sepp1 expression in cultured hepatocytes. We examined the actions of SeP on VEGF signalling and VEGF-induced angiogenesis in HUVECs. We assessed wound healing in mice with hepatic SeP overexpression or SeP deletion. The blood flow recovery after ischaemia was also examined by using hindlimb ischaemia model with Sepp1-heterozygous-knockout mice. Results Treatment with glucose increased gene expression and transcriptional activity for Sepp1 in H4IIEC hepatocytes. Physiological concentrations of SeP inhibited VEGF-stimulated cell proliferation, tubule formation and migration in HUVECs. SeP suppressed VEGF-induced reactive oxygen species (ROS) generation and phosphorylation of VEGF receptor 2 (VEGFR2) and extracellular signal-regulated kinase 1/2 (ERK1/2) in HUVECs. Wound closure was impaired in the mice overexpressing Sepp1, whereas it was improved in SeP-/-mice. SeP+/-mice showed an increase in blood flow recovery and vascular endothelial cells after hindlimb ischaemia. Conclusions/interpretation The hepatokine SeP may be a novel therapeutic target for impaired angiogenesis in type 2 diabetes. © 2014 Springer-Verlag Berlin Heidelberg.
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