Hiroshi Itoh

Keio University, Edo, Tōkyō, Japan

Are you Hiroshi Itoh?

Claim your profile

Publications (539)2017.5 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Besides an established medication for hypercholesterolemia, bile acid binding resins (BABRs) present antidiabetic effects. Although the mechanisms underlying these effects are still enigmatic, GLP-1 appears to be involved. In addition to a few reported mechanisms, we propose prohormone convertase 1/3 (PC1/3), an essential enzyme of GLP-1 production, as a potent molecule in the GLP-1 release induced by BABRs. In our study, the BABR colestimide leads to TGR5-dependent induction of PC1/3 gene expression. Here, we focused on the alteration of intestinal bile acid composition and consequent increase of total TGR5 agonistic activity, to explain the TGR5 activation. Furthermore, we demonstrate that Nuclear factor of activated T cells (NFAT) mediates the TGR5-triggered PC1/3 gene expression. Altogether, our data indicate that the TGR5-dependent intestinal PC1/3 gene expression supports the BABR-stimulated GLP-1 release. We also propose a combination of BABR and DPP-4 inhibitor in the context of GLP-1-based antidiabetic therapy.
    No preview · Article · Jan 2016 · Endocrinology
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Objective This retrospective study evaluated the long-term efficacy of sitagliptin and the factors contributing to its glucose-lowering effect. Methods Six hundred and sixteen dipeptidyl peptidase-4 inhibitor-naïve outpatients with type 2 diabetes who began sitagliptin treatment between December 1, 2009 and December 31, 2011 were included in this study. The inclusion criteria were that the patient had regularly visited our hospital for a period of <700 days from the initiation of sitagliptin treatment and the measurement of hemoglobin A1c (HbA1c) had been performed at 0, 3, 6, 12, 18, and 24 months after the initiation of treatment. From the population of 616 patients, 447 and 169 had received sitagliptin for [1]700 and <700 days, respectively. The primary endpoint was ΔHbA1c at 24 months. The factors associated with the hypoglycemic effect of sitagliptin were also investigated. Results Sitagliptin treatment significantly decreased the level of HbA1c, and the hypoglycemic effect was sustained for at least 2 years. The baseline HbA1c level, duration of diabetes, Δbody weight value, and ΔHbA1c value at 3 months were independently associated with the hypoglycemic effect of sitagliptin. Conclusion Sitagliptin has a long-term hypoglycemic effect in type 2 diabetes patients. A patient’s ΔHbA1c at 3 months may be a predictor of their ΔHbA1c at 24 months.
    Full-text · Article · Dec 2015 · Internal Medicine
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background: Primary biliary cirrhosis (PBC) is an immune-mediated chronic cholestatic liver disease, characterized by increased concentrations of serum IgM and the presence of circulating anti-mitochondrial antibodies. Although bone diseases such as osteoporosis or osteodystrophy are commonly associated with PBC, osteomalacia which is caused by abnormal vitamin D metabolism, mineralization defects, and phosphate deficiency has not been recognized as a complication of PBC. Case presentation: We report the case of a 49-year-old Japanese woman who complained of multiple fractures. Hypophosphatemic osteomalacia was diagnosed from a low serum phosphorus level, 1,25-dihydroxyvitamin D3 level, high levels of bone specific alkaline phosphatase and the findings of bone scintigraphy, although a bone biopsy was not performed. Twenty four hour urine demonstrated a low renal fractional tubular reabsorption of phosphate, increased fractional excretion of uric acid and generalized aminoaciduria. An intravenous bicarbonate loading test suggested the presence of proximal renal tubular acidosis (RTA). These biochemical data indicated Fanconi syndrome with proximal RTA. A kidney biopsy demonstrated the features of tubulointerstitial nephritis (TIN). Conclusion: In this case, asymptomatic PBC was shown to induce TIN with Fanconi syndrome with dysregulation of electrolytes and vitamin D metabolism, which in turn led to osteomalacia with multiple fractures. Osteomalacia has not been recognized as a result of the renal involvement of PBC. PBC and its rare complication of TIN with Fanconi syndrome should be considered in adult patients with unexplained osteomalacia even in the absence of liver dysfunction.
    Preview · Article · Nov 2015 · BMC Nephrology
  • [Show abstract] [Hide abstract]
    ABSTRACT: Introduction: The prorenin receptor ((P)RR) contributes to the regulation of the tissue renin-angiotensin system (RAS) and the function of V-ATPase, which are essential for Wnt signaling. Thus, (P)RRs may be involved in the control both of feto-placental and maternal circulation during pregnancy. This study was conducted to clarify how placental (P)RR expression and plasma soluble (P)RR [s(P)RR] levels are associated with blood pressure elevations and renal function during pregnancy. Methods: We conducted a cross-sectional study, conducted at Saitama medical center in 2010-2013. Preeclamptic women (n = 16) diagnosed according to the criteria of Japan Society of Obstetrics and Gynecology and normotensive pregnant women (n = 15) participated in the study. We measured the expression of (P)RR in the placenta, plasma s(P)RR levels, systolic blood pressure (SBP), and estimated glomerular filtration rate (eGFR). Results: Placental expression of (P)RR was significantly higher in preeclamptic women than in normotensive pregnant women. The plasma s(P)RR levels were significantly higher in preeclamptic women than in normotensive pregnant women. Systolic blood pressure (SBP) was positively correlated with placental (P)RR levels (P = 0.0001) and plasma s(P)RR levels (P = 0.005) in all pregnant women. In preeclamptic women, SBP was positively correlated with placental (P)RR levels (P = 0.004), but not with plasma s(P)RR levels (P = 0.15). The eGFR was negatively correlated with placental (P)RR levels (P = 0.02) and plasma s(P)RR levels (P = 0.0002) in all pregnant women. In preeclamptic women, eGFR was negatively correlated with plasma s(P)RR levels (P = 0.006), but not with placental (P)RR levels (P = 0.93). Discussion: Placental (P)RR can be involved in blood pressure regulation via the tissue RAS. On the other hand, plasma s(P)RR may be involved in the pathogenesis of decreased renal function in preeclampsia.
    No preview · Article · Nov 2015 · Placenta
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Though recommended for pregnant women at risk of preterm birth to improve perinatal outcomes, antenatal corticosteroid (ACS) treatment can cause maternal hyperglycemia, especially in cases of glucose intolerance. A standardized protocol for preventing hyperglycemia during ACS treatment remains to be established. We herein retrospectively investigated the time-dependent changes in insulin dose required for maternal glycemic control during ACS treatment in gestational diabetes (GDM). Twelve singleton pregnant women with GDM who received 12 mg of betamethasone intramuscularly twice 24 hours apart were included in this analysis. Of those, eight also received ritodrine hydrochloride for preterm labor. The blood glucose levels were maintained at 70-120 mg/dL with continuous intravenous infusion of insulin and nothing by mouth for 48 hours after the first betamethasone administration. After the first dose of betamethasone, the insulin dosage needed for glycemic control gradually increased and reached a maximum (6.6 ± 5.8 units/hr) at 10 hours, then, decreased to 4.1 ± 1.5 units/hr at 24 hours. Similar changes in the insulin requirement were found after the second betamethasone dose (the maximum insulin dosage: 5.5 ± 1.6 units/hr at 9 hours following the second administration). Women treated with ritodrine hydrochloride needed more insulin, than those without ritodrine hydrochloride treatment (130.8 ± 15.0 vs. 76.8 ± 15.2 units/day, respectively, p < 0.05). Our data indicated that the requirement for insulin is highest 9-10 hours after each dose of betamethasone. When GDM is treated with ACS, levels of blood glucose should be carefully monitored, especially in patients treated with ritodrine hydrochloride.
    Full-text · Article · Oct 2015 · Endocrine Journal
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: microRNAs (miRNAs) are non-coding small RNAs that regulate embryonic development, cell differentiation and pathological processes via interaction with mRNA. Epithelial-mesenchymal transition (EMT) is pathological process that involves in a variety of diseases such as cancer or fibrosis. Methods: In this study, we identified miR-363 as a potent inducer of EMT by microarray analysis in human kidney tubular cells, and analyzed the function and mechanisms of miR-363. Results: Overexpression of miR-363 induced mesenchymal phenotypes with loss of epithelial phenotypes in human kidney tubular cells. In addition, in vitro scratch assay demonstrated that miR-363 promotes cell migration of primary culture of human kidney tubular cells. We identified TWIST/canonical WNT pathway as the downstream effecter of miR-363, and inhibition of canonical WNT by small molecule, IWR-1, attenuated EMT induced by miR-363. Conclusion: miR-363 induces transdifferentiation of human kidney tubular cells via upregulation of TWIST/canonical WNT pathway.
    No preview · Article · Sep 2015 · Clinical and Experimental Nephrology
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background and Objective Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are becoming one of the major therapeutic options for the treatment of type 2 diabetes mellitus (T2DM). This study was conducted as an exploratory analysis to clarify the effects of liraglutide, a GLP-1RA, on beta cell function, fat distribution and pancreas volume compared with metformin in Japanese overweight/obese patients with T2DM. Methods A subpopulation of the Keio study for Initial treatment of type 2 Diabetes with Liraglutide versus Metformin (KIND-LM) study participants (n = 20, 10 in oral metformin group and 10 in subcutaneous liraglutide group) who were enrolled at Keio University Hospital and underwent frequently sampled mixed meal tolerance test (MTT) and abdominal computed tomography (CT) at weeks 0 and 24 were included in this analysis. The patients were treated with either metformin or liraglutide throughout the 24-week study period. Results Changes in glycemic parameters such as glycated hemoglobulin (HbA1c), glycated albumin and 1,5-anhydroglucitol at week 24 were comparable between the groups. An oral minimal model based on MTT revealed that static-phase beta cell responsiveness (Φ s) and static-phase disposition index were significantly increased at week 24 in the liraglutide group but not in the metformin group. There was no significant change in fat distribution as well as body weight at week 24 in either group. Serum amylase and lipase levels modestly but significantly increased in the liraglutide group during the study; however, there was no incidence of pancreatitis and pancreas volume was not changed in the liraglutide group. Conclusion Liraglutide monotherapy for 24 weeks improved beta cell responsiveness with no change in either body weight or fat distribution. Further investigation is needed to clarify the mechanism by which liraglutide increases serum pancreatic enzymes. Trial Registration The University Hospital Medical Information Network (UMIN) Clinical Trials Registry (http:// www. umin. ac. jp/ ctr/ ); UMIN000004243.
    No preview · Article · Sep 2015 · Clinical Drug Investigation
  • [Show abstract] [Hide abstract]
    ABSTRACT: Because a physical decline correlates with an increased risk of a wide range of disease and morbidity, an improvement of physical performance is expected to bring significant clinical benefits. The primary cause of physical decline in 5/6 nephrectomized (5/6Nx) CKD (chronic kidney disease) model mice has been regarded as a decrease in muscle mass; however, our recent study showed that a decrease in muscle mitochondria plays a critical role. In the present study, we examined the effects of a gastric hormone ghrelin, which has been reported to promote muscle mitochondrial oxidation, on the physical decline in the CKD model mice, focusing on the epigenetic modulations of a mitochondrial activator gene, peroxisome proliferator-activated receptor-γ coacivator-1α (PGC-1α). Ghrelin treatment improved a decline in exercise endurance of 5/6Nx mice, associated with an increase in both of the muscle mass and mitochondrial amount. The expression level of PGC-1α was decreased in the skeletal muscle of 5/6Nx mice, which was associated with an increase in the methylation ratio of the cytosine at 260 base pairs upstream (C-260) of the initiation point. Conversely, ghrelin treatment de-methylated the cytosine residue and increased the expression of PGC-1α. A representative muscle anabolic factor, insulin-like growth factor-1 (IGF-1), did not affect the expression of PGC-1α and muscle mitochondrial amount, though it increased muscle mass. As a result, IGF-1 treatment in 5/6Nx mice did not increase the decreased exercise endurance as effectively as ghrelin treatment did. These findings indicate an advantage of ghrelin treatment for a recovery of physical decline.
    No preview · Article · Aug 2015 · Endocrinology
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background Plasma-oxidized (ox) low-density lipoprotein (LDL) is an atherogenic lipoprotein. The distribution of ox-LDL in plasma LDL subfractions and the effect of statins on this distribution have not been investigated in detail. Objective We examined the distribution of cholesterol and ox-LDL in 3 ultracentrifugally separated plasma LDL subfractions and investigated the effects of a statin, rosuvastatin, on the levels of these lipoproteins. Materials and methods Thirty-one polygenic hypercholesterolemic subjects were included in this study. Levels of cholesterol and ox-LDL in 3 plasma LDL subfractions and plasma levels of remnant-like particle cholesterol, ox-LDL, and adiponectin were measured after 0, 3, 6, and 12 months of treatment with rosuvastatin. Sequential ultracentrifugation was performed to subfractionate plasma lipoproteins. Results The mean daily dose of rosuvastatin over the 12 months of treatment was 2.9 ± 1.0 mg (mean ± standard deviation). The cholesterol subfraction distribution was 43 ± 10% as low-density LDL, 46 ± 8% as medium-density LDL, and 13 ± 5% as high-density LDL. Similarly, the distribution of ox-LDL was 31 ± 10% as low-density LDL, 48 ± 7% as medium-density LDL, and 22 ± 8% as high-density LDL. After 12 months of treatment with rosuvastatin, the level of cholesterol was significantly reduced in all 3 subfractions (P < .0001), as was the level of ox-LDL (P < .0001). Furthermore, the plasma cholesterol level in high-density lipoprotein2 increased significantly. Conclusions The distribution of ox-LDL in plasma LDL subfractions was more skewed toward the denser subfractions, compared with cholesterol. Rosuvastatin treatment significantly reduced plasma levels of cholesterol and ox-LDL in all LDL subfractions.
    No preview · Article · Aug 2015 · Journal of Clinical Lipidology
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Real-life safety and efficacy of sorafenib in advanced renal cell carcinoma in a nationwide patient population were evaluated by post-marketing all-patient surveillance. All patients with unresectable or metastatic renal cell carcinoma in Japan who started sorafenib therapy from February 2008 to September 2009 were registered and followed for up to 12 months. Baseline characteristics, treatment status, tumor response, survival and safety data were recorded by the prescribing physicians. Safety and efficacy were evaluated in 3255 and 3171 patients, respectively. The initial daily dose was 800 mg in 78.2% of patients. Median duration of treatment was 6.7 months and the mean relative dose intensity was 68.4%. Overall, 2227 patients (68.4%) discontinued the treatment by 12 months, half of which (52.0% of discontinued patients) were due to adverse events. The most common adverse drug reactions were hand-foot skin reaction (59%), hypertension (36%), rash (25%) and increase in lipase/amylase (23%). The median progression-free survival was 7.3 months (95% confidence intervals: 6.7-8.1), and the overall survival rate at 1 year was 75.4% (73.5-77.1). Prognostic factors for overall survival were mostly consistent with those in previous clinical trials in the univariate analysis and largely similar to those for progression-free survival and duration of treatment in the multivariate analysis. Sorafenib for the treatment of advanced renal cell carcinoma under the labeled dose was feasible in daily medical practice, for its acceptable toxicity profile and favorable clinical benefit that were consistent with those in clinical trials. © The Author 2015. Published by Oxford University Press.
    Full-text · Article · Jul 2015 · Japanese Journal of Clinical Oncology
  • [Show abstract] [Hide abstract]
    ABSTRACT: The objective was to clarify whether dietary palmitic acid supplementation affects glucose-stimulated insulin secretion (GSIS) and the endoplasmic reticulum (ER) stress pathway in pancreatic islets in mice. Eight-week-old male C57BL/6J mice were randomly divided into three treatment diet groups: control diet, palmitic acid-supplemented diet (PAL) and oleic acid-supplemented diet (OLE). After 2 weeks of treatment, intraperitoneal glucose tolerance test and intraperitoneal insulin tolerance test were performed. GSIS was assessed by pancreatic perfusion in situ with basal (100 mg/dL) glucose followed by a high (300 mg/dL) glucose concentration. We measured mRNA levels of ER stress markers such as C/EBP homologous protein (CHOP), immunoglobulin heavy-chain binding protein (BIP) and X-box binding protein (XBP)-1 using real-time polymerase chain reaction (PCR) analyses in isolated islets. Immunohistochemical staining was also performed. Mice fed PAL showed significantly decreased glucose tolerance (p < 0.05). In the perfusion study, GSIS was significantly suppressed in the PAL group (p < 0.05). Semi-quantitative RT-PCR revealed that islet CHOP, BIP, and XBP-1 mRNA expression were significantly increased in the PAL group (p < 0.05). TUNEL-positive β-cells were not detected in all groups. Dietary palmitic acid-supplementation for 2 weeks might suppress GSIS and induce ER stress in pancreatic islets in mice, in the early stage of lipotoxicity.
    No preview · Article · Jul 2015 · Endocrine Research
  • [Show abstract] [Hide abstract]
    ABSTRACT: Although relationships of serum bilirubin concentration with estimated glomerular filtration rate (eGFR) and urinary albumin excretion (UAE) in patients with type 2 diabetes have been reported, whether such relationships exist in patients with type 1 diabetes is unknown. A total of 123 patients with type 1 diabetes were investigated in this cross-sectional study. The relationship between bilirubin (total and indirect) concentrations and log(UAE) as well as eGFR was examined by Pearson's correlation analyses. Multivariate regression analyses were used to assess the association of bilirubin (total and indirect) with eGFR as well as log(UAE). A positive correlation was found between serum bilirubin concentration and eGFR; total bilirubin (r=0.223, p=0.013), indirect bilirubin (r=0.244, p=0.007). A negative correlation was found between serum bilirubin concentration and log(UAE); total bilirubin (r=-0.258, p=0.005), indirect bilirubin (r=-0.271, p=0.003). Multivariate regression analyses showed that indirect bilirubin concentration was an independent determinant of eGFR and log(UAE). Bilirubin concentration is associated with both eGFR and log(UAE) in patients with type 1 diabetes. Bilirubin might have a protective role in the progression of type 1 diabetic nephropathy. Copyright © 2015. Published by Elsevier Inc.
    No preview · Article · Jul 2015 · Journal of diabetes and its complications
  • [Show abstract] [Hide abstract]
    ABSTRACT: Proteinuria is a central component of chronic kidney disease and an independent risk factor for cardiovascular disease. Kidney podocytes have an essential role as a filtration barrier against proteinuria. Kruppel-like Factor 4 (KLF4) is expressed in podocytes and decreased in glomerular diseases leading to methylation of the nephrin promoter, decreased nephrin expression and proteinuria. Treatment with an angiotensin receptor blocker (ARB) reduced methylation of the nephrin promoter in murine glomeruli of an adriamycin nephropathy model with recovery of KLF4 expression and a decrease in albuminuria. In podocyte-specific KLF4 knockout mice, the effect of ARB on albuminuria and the nephrin promoter methylation was attenuated. In cultured human podocytes, angiotensin II reduced KLF4 expression and caused methylation of the nephrin promoter with decreased nephrin expression. In patients, nephrin promoter methylation was increased in proteinuric kidney diseases with decreased KLF4 and nephrin expression. KLF4 expression in ARB-treated patients was higher in patients with than without ARB treatment. Thus, angiotensin II can modulate epigenetic regulation in podocytes and ARB inhibits these actions in part via KLF4 in proteinuric kidney diseases. This study provides a new concept that renin-angiotensin system blockade can exert therapeutic effects through epigenetic modulation of the kidney gene expression.Kidney International advance online publication, 24 June 2015; doi:10.1038/ki.2015.178.
    No preview · Article · Jun 2015 · Kidney International
  • Source
    Shu Wakino · Kazuhiro Hasegawa · Hiroshi Itoh
    [Show abstract] [Hide abstract]
    ABSTRACT: Sirtuin is a nicotinamide adenine dinucleotide-dependent deacetylase. One of its isoforms, Sirt1, is a key molecule in glucose, lipid, and energy metabolism. The renal protective effects of Sirt1 are found in various models of renal disorders with metabolic impairment, such as diabetic nephropathy. Protective effects include the maintenance of glomerular barrier function, anti-fibrosis effects, anti-oxidative stress effects, and regulation of mitochondria function and energy metabolism. Various target molecules subject to direct deacetylation or epigenetic gene regulation have been identified as effectors of the renal protective function of sirtuin. Recently, it was demonstrated that Sirt1 expression decreases in proximal tubules before albuminuria in a mouse model of diabetic nephropathy, and that albuminuria is suppressed in proximal tubule-specific mice overexpressing Sirt1. These findings suggest that decreased Sirt1 expression in proximal tubular cells causes abnormal nicotine metabolism and reduces the supply of nicotinamide mononucleotide from renal tubules to glomeruli. This further decreases expression of Sirt1 in glomerular podocytes and increases expression of a tight junction protein, claudin-1, which results in albuminuria. Activators of the sirtuin family of proteins, including resveratrol, may be important in the development of new therapeutic strategies for treating metabolic kidney diseases, including diabetic nephropathy.Kidney International advance online publication, 17 June 2015; doi:10.1038/ki.2015.157.
    Preview · Article · Jun 2015 · Kidney International
  • [Show abstract] [Hide abstract]
    ABSTRACT: The present report describes 6 cases of adrenal venous sampling (AVS) in patients who underwent computed tomography (CT) during arteriography because cannulation of right adrenal veins was otherwise difficult. CT was performed during arteriography to obtain information on the location and direction of the right adrenal vein. Two right adrenal veins were visualized in 1 case. The right central adrenal vein was not visualized in 1 case owing to an injury from a previous unsuccessful AVS procedure, but the right renal capsular vein was well visualized. CT during arteriography could contribute to a high AVS success rate. Copyright © 2015 SIR. Published by Elsevier Inc. All rights reserved.
    No preview · Article · Jun 2015 · Journal of vascular and interventional radiology: JVIR

  • No preview · Conference Paper · Jun 2015
  • [Show abstract] [Hide abstract]
    ABSTRACT: New erythropoiesis-stimulating agents with a longer half-life have been developed for the treatment of anemia in patients with end-stage renal disease. This study evaluated the efficacy of darbepoetin alfa (DA) and long-acting epoetin beta pegol (continuous erythropoietin receptor activator, CERA) in patients on peritoneal dialysis (PD). Twenty-nine patients who had undergone PD for at least 6 months and were iron replacement-naïve and negative for inflammatory parameters were enrolled. Hemoglobin (Hgb) levels and blood pressure were evaluated before and after switching from DA to CERA. Percent transferrin saturation (TSAT), serum ferritin levels and blood pressure were also assessed. Twenty-eight patients were subject to the analysis, excluding one patient with a decrease in Hgb by ≥10%. Switching from DA to CERA did not alter Hgb levels. The doses of DA and CERA after 12 month treatment of each agent were 118.48 ± 79.63 and 89.88 ± 47.50 μg/4 weeks, respectively (conversion ratio, 1:0.76). The CERA dose administered during the final 6 months was abated, compared with that given during the initial 6 months (P = 0.035). The frequency of CERA injection over a 12-month period was less than that of DA (10.0 ± 3.0 vs. 16.4 ± 5.0, P < 0.01). The conversion from DA to CERA did not alter TSAT, but decreased serum ferritin levels (from 202.69 ± 132.57 to 150.15 ± 110.07 ng/mL, P = 0.012) and systolic blood pressure (from 133.8 ± 17.3 to 129.5 ± 11.3 mm Hg, P = 0.024). In PD patients, lower doses and less frequent injection of CERA are sufficient to maintain Hgb at levels similar to those achieved by DA therapy, with improved iron utilization and reduced blood pressure. © 2015 The Authors. Therapeutic Apheresis and Dialysis © 2015 International Society for Apheresis.
    No preview · Article · May 2015 · Therapeutic apheresis and dialysis: official peer-reviewed journal of the International Society for Apheresis, the Japanese Society for Apheresis, the Japanese Society for Dialysis Therapy

  • No preview · Conference Paper · May 2015
  • [Show abstract] [Hide abstract]
    ABSTRACT: Bile acid binding resin (BAR) improves glycaemic control in patients with type 2 diabetes. Although the mechanism is hypothesised to involve the clearance of excess hepatic triglyceride, this hypothesis has not been examined in appropriately designed studies. Therefore, we investigated whether reduced hepatic triglyceride deposition is involved in BAR-mediated improvements in glycaemic control in spontaneous fatty liver diabetic mice without dietary interventions. Male 6-week-old fatty liver Shionogi (FLS) mice were fed a standard diet without or with 1.5% BAR (colestilan) for 6 weeks. Glucose tolerance, insulin sensitivity, hepatic lipid content, and gene expression were assessed. A liver X receptor (LXR) agonist was also administered to activate the LXR pathway. We also retrospectively analysed the medical records of 21 outpatients with type 2 diabetes who were treated with colestilan for ≥6 months. BAR enhanced glucose tolerance and insulin sensitivity in FLS mice without altering fat mass. BAR improved hepatic insulin sensitivity, increased IRS2 expression, and decreased SREBP expression. BAR reduced hepatic cholesterol levels but not hepatic triglyceride levels. BAR also reduced the expression of LXR target genes, and LXR activation abolished the BAR-mediated improvements in glycaemic control. Colestilan significantly lowered serum cholesterol levels and improved glycaemic control in patients with type 2 diabetes. BAR improved hepatic insulin resistance in FLS mice by reducing hepatic cholesterol without affecting hepatic triglyceride levels or body fat distribution. Our study revealed that BAR improves glycaemic control at least in part by downregulating the hepatic cholesterol-LXR-IRS2 pathway. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
    No preview · Article · Apr 2015 · Diabetes Research and Clinical Practice
  • [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this study was 1) to clarify beta cell regenerative capacity in the face of glucocorticoid (GC)-induced insulin resistance and 2) to clarify the change in beta and alpha cell mass in GC-induced diabetes in humans. We obtained the pancreases from 100 Japanese autopsy cases. The cases were classified according to whether or not they had received GC therapy prior to death and the presence or absence of diabetes. Fractional beta cell area (%BCA) and alpha cell area (%ACA) were quantified and the relationship with GC therapy was evaluated. As a result, in non-diabetic cases, there was no significant difference in %BCA between cases with and without GC therapy (1.66 ± 1.05% vs. 1.21 ± 0.59%, P = 0.13). %ACA was also not significantly different between the two groups. In cases with type 2 diabetes, both %BCA and %ACA were significantly reduced compared with those in non-diabetic controls; however, neither %BCA nor %ACA was significantly decreased in cases with GC-induced diabetes. There was a significant negative correlation between %BCA and HbA1c measured before death; however, this relationship was attenuated in cases with GC therapy. In conclusion, the present study suggests that beta and alpha cell mass remain largely unchanged in the face of GC-induced insulin resistance in Japanese individuals, implying limited capacity of beta cell regeneration in adult humans. The absence of apparent beta cell deficit in cases with GC-induced diabetes suggests that GC-induced diabetes is mainly caused by insulin resistance and/or beta cell dysfunction, but not necessarily a deficit of beta cell mass. © 2015 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.
    No preview · Article · Apr 2015 · Diabetes

Publication Stats

13k Citations
2,017.50 Total Impact Points

Institutions

  • 2006-2015
    • Keio University
      • Department of Internal Medicine
      Edo, Tōkyō, Japan
  • 2014
    • Yamaguchi University
      Yamaguti, Yamaguchi, Japan
  • 2008-2013
    • University of Fukui
      • • Department of Pathological Sciences
      • • Division of Tumor Pathology
      Фукуй, Fukui, Japan
    • University of Michigan
      Ann Arbor, Michigan, United States
  • 1986-2011
    • Kyoto University
      • • Department of Medicine and Clinical Science
      • • Department of Pharmacy
      • • Primate Research Institute
      Kioto, Kyōto, Japan
  • 2010
    • The Jikei University School of Medicine
      • Department of Internal Medicine
      Edo, Tokyo, Japan
  • 1998-2009
    • Kobe University
      • • Division of Pathology
      • • Faculty of Medicine
      Kōbe, Hyōgo, Japan
  • 2004-2008
    • Miyazaki University
      • • Faculty of Medicine
      • • Department of Pathology
      • • Department of Neurosurgery
      Miyazaki-shi, Miyazaki-ken, Japan
    • Kumamoto University
      Kumamoto, Kumamoto, Japan
  • 2007
    • Kagawa University
      • Department of Pharmacology
      Takamatu, Kagawa, Japan
  • 2001-2003
    • Asahikawa Medical University
      • Department of Internal Medicine
      Асахикава, Hokkaido, Japan
  • 2002
    • Miyazaki Medical Association Hospital
      Миядзаки, Miyazaki, Japan