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We sought to describe global patterns in achievement of risk factor control for primary prevention in patients with T2D and explore the association of country's GNI/capita with risk factor control.The DISCOVER study is a prospective, observational study of patients with T2D from 38 countries enrolled at initiation of second-line glucose-lowering therapy. We examined achievement of risk factor control (glycosylated hemoglobin7%, blood pressure140/90 mmHg, prescription of a statin) at 3 years among those without optimal control at baseline. Countries were stratified by gross national income (GNI)/capita, from 2017). We examined the impact of country GNI/capita with achievement of risk factor control.Our cohort included 9613 patients with T2D and without baseline cardiovascular disease (mean age 57.2 ± 8.7 years, 47.9% women). At baseline, 6354/7646 patients (83.1%) had suboptimal glucose control, 3449/9200 patients (37.5%) had suboptimal BP control, and 2800/4221 patients (66.7%) were not on an appropriate statin (sample sizes differed due to missing covariate data). Optimal control at 3 years of follow-up was achieved in 41% (glucose), 56% (blood pressure), and 29% (statins) of patients. There was significant variability in achievement of risk factor control across countries but no association between country GNI/capita with achievement of risk factor control (p 0.08 for all).In a global, prospective study of patients with T2D, we found that cardiovascular risk factor control achievement was suboptimal despite 3 years of follow-up in specialized health care systems. Neither country-level nor patient-level socioeconomic factors fully explained this finding.

Autophagy is known to play an essential role in intracellular quality control through the degradation of damaged organelles and components. We previously demonstrated that β-cell-specific autophagy deficient mice, which lack Atg7, exhibited impaired glucose tolerance, accompanied by the accumulation of sequestosome 1/p62 (hereafter referred to as p62). Whereas p62 has been reported to play essential roles in regulating cellular homeostasis in the liver and adipose tissue, we previously showed that β-cell-specific p62 deficiency does not cause any apparent impairment in glucose metabolism. In the present study, we investigated the roles of p62 in β cells under autophagy-deficient conditions, by simultaneously inactivating both Atg7 and p62 in a β-cell specific manner. Whereas p62 accumulation was substantially reduced in the islets of Atg7 and p62 double-deficient mice, glucose tolerance and insulin secretion were comparable to Atg7 single-deficient mice. Taken together, these findings suggest that the p62 accumulation appears to have little effect on β-cell function under conditions of autophagy inhibition.

Autophagy is known to play a pivotal role in β-cell function. While the lifelong inhibition of autophagy through Atg7 deletion in β cells has been demonstrated to lead to impaired glucose tolerance together with β-cell dysfunction, the temporal association between autophagy inhibition and β-cell dysfunction remains unclear. To address such questions, inducible β-cell-specific Atg7-knockout (iβAtg7

Triglyceride (TG) is a tri-ester composed of a glycerol and 3 fatty acids. Degradation of TG in adipose tissue is increased in the fasting state but inhibited in the postprandial state. Although insulin suppresses adipose TG degradation, patients with insulin resistance have high concentrations of insulin and free glycerol (FG) in the fasting state.We examined whether the fasting FG concentration reflects visceral obesity and insulin sensitivity in middle-aged Japanese men.We measured the fasting serum FG concentration in 72 males aged 30 to 50 years using a simple enzymatic method. The subjects were divided into tertiles according to their homeostasis model assessment of insulin resistance (HOMA-IR). Besides routine glucose- and lipid-related parameters, we determined insulin sensitivity as the rate of glucose disappearance in a 2-step hyperinsulinemic-euglycemic clamp and the abdominal visceral fat area (VFA) by magnetic resonance imaging.The highest HOMA-IR tertile group had a higher fasting FG concentration than the middle- and lowest-tertile groups (0.077 ± 0.024 vs 0.063 ± 0.017 and 0.061 ± 0.016 mmol/L, P .05 and P .01). The FG concentration was positively correlated with VFA (rs = 0.36; P .01) and the HOMA-IR score (rs = 0.26, P .05) but negatively correlated with insulin sensitivity (rs = -0.26, P .05). Multivariate regression analysis revealed that the FG concentration is independently associated with VFA and insulin sensitivity.The fasting FG concentration reflects VFA and insulin sensitivity in middle-aged Japanese men. The fasting FG concentration may be a potential surrogate marker of visceral obesity and insulin resistance in outpatients.

The glymphatic system is a glial-based perivascular network that promotes brain metabolic waste clearance. Reduced glymphatic flow has been observed in rat models of type 2 diabetes and hypertension, indicating the role of vascular risk factors in the glymphatic system. However, little is known about how vascular risk factors affect the human glymphatic system. The present study aims to assess the relationships between metabolic syndrome (MetS), a cluster of vascular risk factors, and the glymphatic system function using diffusion magnetic resonance imaging (MRI)-based measures of water diffusivity in the glymphatic compartments, including the brain interstitial space and perivascular spaces around the deep medullary vein. We hypothesized that vascular risk factors are associated with glymphatic dysfunction, leading to cognitive impairment in older adults.This cross-sectional study assessed 61 older adults (age range, 65-82 years) who had participated in the Bunkyo Health Study, including 15 healthy controls (mean age, 70.87 ± 4.90 years) and 46 individuals with MetS (mean age, 71.76 ± 4.61 years). Fractional volume of extracellular-free water (FW) and an index of diffusion tensor imaging along the perivascular space (DTI-ALPS) were used as indirect indicators of water diffusivity in the interstitial extracellular and perivenous spaces of white matter, respectively.After adjusting for age, sex, years of education, total Fazekas scale, Pittsburgh sleep quality index (PSQI) score, and intracranial volume (ICV), a significantly (P = 0.030; Cohen's d = 1.01) higher FW was observed in individuals with MetS than in the healthy controls. Furthermore, individuals with MetS had a significantly (P = 0.031; Cohen's d = 0.86) lower ALPS index than the healthy controls, with age, sex, years of education, total Fazekas scale, PSQI score, ICV, fractional anisotropy, and mean diffusivity included as confounding factors. Higher FW was significantly associated with lower ALPS index (r = -0.37; P = 0.004). Multiple linear regression (MLR) with backward elimination analyses showed that higher diastolic blood pressure (BP; standardized β = 0.33, P = 0.005) was independently associated with higher FW, whereas higher fasting plasma glucose levels (standardized β = -0.63, P = 0.002) or higher Brinkman index of cigarette consumption cumulative amount (standardized β = -0.27, P = 0.022) were associated with lower ALPS index. The lower ALPS index (standardized β, 0.28; P = 0.040) was associated with poorer global cognitive performance, which was determined using the Japanese version of the Montreal Cognitive Assessment (MOCA-J) scores. Finally, partial correlation analyses showed a significant correlation between higher FW and lower MOCA-J scores (r = -0.35; P = 0.025) and between higher FW and higher diastolic BP (r = 0.32, P = 0.044).The present study shows the changes in diffusion MRI-based measures reflected by the higher FW and lower ALPS index in older adults with MetS, possibly due to the adverse effect of vascular risk factors on the glymphatic system. Our findings also indicate the associations between the diffusion MRI-based measures and elevated diastolic BP, hyperglycemia, smoking habit, and poorer cognitive performance. However, owing to the limitations of this study, the results should be cautiously interpreted.

The emergence of bihormonal (BH) cells expressing insulin and glucagon has been reported under diabetic conditions in humans and mice. Whereas lineage tracing studies demonstrated that glucagon-producing α cells can be reprogrammed into BH cells, the underlying dynamics of the conversion process remain poorly understood. In the present study, we investigated the identities of pancreatic endocrine cells by genetic lineage tracing under diabetic conditions. When β-cell ablation was induced by alloxan (ALX), a time-dependent increase in BH cells was subsequently observed. Lineage tracing experiments demonstrated that BH cells originate from α cells, but not from β cells, in ALX-induced diabetic mice. Notably, supplemental insulin administration into diabetic mice resulted in a significant increase in α-cell-derived insulin-producing cells that did not express glucagon. Furthermore, lineage tracing in Ins2Akita diabetic mice demonstrated a significant induction of α-to-β conversion. Thus, adult α cells have plasticity, which enables them to be reprogrammed into insulin-producing cells under diabetic conditions, and this can be modulated by supplemental insulin administration.

Autophagy is a mechanism of bulk protein degradation that plays an important role in regulating homeostasis in many organisms. Among several methods for evaluating its activity, a fluorescent reporter GFP-LC3-RFP-LC3ΔG, in which GFP-LC3 is cleaved by ATG4 following autophagic induction and degraded in lysosome, has been used for monitoring autophagic flux, which is the amount of lysosomal protein degradation. In this study, we modified this reporter by exchanging GFP for pHluorin, which is more sensitive to low pH, and RFP to mCherry, to construct pHluorin-LC3-mCherry reporter. Following starvation or mTOR inhibition, the increase of autophagic flux was detected by a decrease of the fluorescent ratio of pHluorin to mCherry; our reporter was also more sensitive to autophagy-inducing stimuli than the previous one. To establish monitoring cells for mouse genome-wide screening of regulators of autophagic flux based on CRISPR/Cas9 system, after evaluating knockout efficiency of clones of Cas9-expressing MEFs, we co-expressed our reporter and confirmed that autophagic flux was impaired in gRNA-mediated knockout of canonical autophagy genes. Finally, we performed genome-wide gRNA screening for genes inhibiting starvation-mediated autophagic flux and identified previously reported genes such as Atgs. Thus, we have successfully established a system for screening of genes regulating autophagic flux with our pHluorin-LC3-mCherry reporter in mice.

Metabolic syndrome (MetS) is defined as a complex of interrelated risk factors for type 2 diabetes and cardiovascular disease, including glucose intolerance, abdominal obesity, hypertension, and dyslipidemia. Studies using diffusion tensor imaging (DTI) have reported white matter (WM) microstructural abnormalities in MetS. However, interpretation of DTI metrics is limited primarily due to the challenges of modeling complex WM structures. The present study used fixel-based analysis (FBA) to assess the effect of MetS on the fiber tract-specific WM microstructure in older adults and its relationship with MetS-related measurements and cognitive and locomotor functions to better understand the pathophysiology of MetS.Fixel-based metrics, including microstructural fiber density (FD), macrostructural fiber-bundle cross-section (FC), and a combination of FD and FC (FDC), were evaluated in 16 healthy controls (no components of MetS; four men; mean age, 71.31 ± 5.06 years), 57 individuals with premetabolic syndrome (preMetS; one or two components of MetS; 29 men; mean age, 72.44 ± 5.82 years), and 46 individuals with MetS (three to five components of MetS; 27 men; mean age, 72.15 ± 4.97 years) using whole-brain exploratory FBA. Tract of interest (TOI) analysis was then performed using TractSeg across 14 selected WM tracts previously associated with MetS. The associations between fixel-based metrics and MetS-related measurements, neuropsychological, and locomotor function tests were also analyzed in individuals with preMetS and MetS combined. In addition, tensor-based metrics (i.e., fractional anisotropy [FA] and mean diffusivity [MD]) were compared among the groups using tract-based spatial statistics (TBSS) analysis.In whole-brain FBA, individuals with MetS showed significantly lower FD, FC, and FDC compared with healthy controls in WM areas, such as the splenium of the corpus callosum (CC), corticospinal tract (CST), middle cerebellar peduncle (MCP), and superior cerebellar peduncle (SCP). Meanwhile, in fixel-based TOI, significantly reduced FD was observed in individuals with preMetS and MetS in the anterior thalamic radiation, CST, SCP, and splenium of the CC compared with healthy controls, with relatively greater effect sizes observed in individuals with MetS. Compared with healthy controls, significantly reduced FC and FDC were only demonstrated in individuals with MetS, including regions with loss of FD, inferior cerebellar peduncle, inferior fronto-occipital fasciculus, MCP, and superior longitudinal fasciculus part I. Furthermore, negative correlations were observed between FD and Brinkman index of cigarette consumption cumulative amount and between FC or FDC and the Trail Making Test (parts B-A), which is a measure of executive function, waist circumference, or low-density lipoprotein cholesterol. Finally, TBSS analysis revealed that FA and MD were not significantly different among all groups.The FBA results demonstrate that substantial axonal loss and atrophy in individuals with MetS and early axonal loss without fiber-bundle morphological changes in those with preMetS within the WM tracts are crucial to cognitive and motor function. FBA also clarified the association between executive dysfunction, abdominal obesity, hyper-low-density lipoprotein cholesterolemia, smoking habit, and compromised WM neural tissue microstructure in MetS.

The aim of this study was to define the relationship between time in range (TIR) and hemoglobin A1c (HbA1c) levels in patients with type 2 diabetes mellitus (T2DM).The glycemic profile of 999 Japanese patients was analyzed with FreeStyle Libre Pro Continuous Glucose Monitoring (FLP-CGM) while they continued their prescribed glucose-lowering medications. FLP-CGM data recorded over 8 consecutive days were analyzed.The regression model for HbA1c on TIR was HbA1c = 9.4966-0.0309 × TIR. The predicted HbA1c level for TIR of 70% was 7.33% and is higher than reports subjecting mostly T1DM. The TIR corresponding to HbA1c 7.0% was 80.64%. The patients with low TIR tended to have long duration of diabetes, used high dose of daily insulin, high body mass index, high HbA1c, liver dysfunction and high triglyceride. Relatively higher percentages of patients of this group used sulfonylureas, glucagon like peptide-1 receptor agonists and insulin.Our data showed predicted HbA1c corresponding to TIR is largely depends on study population, thus is not uniform. Our results provide new insights on the management of T2DM. However, caution should be exercised in extending the HbA1C-TIR relationship using FLP-CGM to any other sensors since there could be a risk of hypoglycemia in doing so.

Inorganic iodine is often used to treat patients with Graves thyrotoxicosis who do not tolerate thionamides due to adverse effects. However, predictors of continued inorganic iodine efficacy have not been fully elucidated. This study aimed to investigate the factors affecting the continued efficacy of potassium iodide (KI) in patients with Graves thyrotoxicosis.In this study, among 1,197 patients with Graves disease who were initially treated with thionamides, we retrospectively studied 24 consecutive Japanese patients whose treatment was changed to KI alone due to the adverse effects of thionamides. We divided these patients into 2 groups: patients who had maintained euthyroid function for at least 180 days (nonrecurrence group, n = 11), and patients who had not maintained euthyroid function for 180 days (recurrence group, n = 13).Free triiodothyronine (FT3) and free thyroxine (FT4) levels on the day of changing from thionamides to KI were statistically higher in the recurrence group than in the nonrecurrence group (FT3, 9.3 [range, 5.2-11.6] vs. 3.7 [3.3-4.8] pg/mL, P = .02 and FT4, 3.6 [1.8-4.5] vs. 1.4 [1.2-1.9] ng/dL, P = .02). FT4 levels on the day of drug change were significantly higher in the recurrence group, even after adjusting for thionamide or KI dose. In the recurrence group, the duration of KI effect was inversed correlated with FT3 and FT4 levels on the day of drug change.Continued efficacy of KI after thionamides might be inversely correlated with thyrotoxicosis severity on the day of drug change.ANOVA = analysis of variance eTV = estimated thyroid volume FT3 = free triiodothyronine FT4 = free thyroxine IQR = interquartile range KI = potassium iodide MMI = thiamazole PTU = propylthiouracil RAIT = radioactive iodine therapy TRAb = TSH receptor antibody TSH = thyroid stimulating hormone.

Summary Background & aims The usefulness of low-carbohydrate diet (LCD) for Japanese patients with type 2 diabetes mellitus (T2DM) has not been fully investigated. Therefore, we compared the effectiveness and safety of LCD with calorie restricted diet (CRD). Methods This prospective, randomized, open-label, comparative study included 66 T2DM patients with HbA1c >7.5% even after receiving repeated education programs on CRD. They were randomly allocated to either the 130g/day LCD group (n = 33) or CRD group (n = 33). Patients received personal nutrition education of CRD or LCD for 30 min at baseline, 1, 2, 4, and 6 months. Patients of the CRD group were advised to maintain the intake of calories and balance of macronutrients (28× ideal body weight calories per day). Patients of the LCD group were advised to maintain the intake of 130 g/day carbohydrate without other specific restrictions. Several parameters were assessed at baseline and 6 months after each intervention. The primary endpoint was a change in HbA1c level from baseline to the end of the study. Results At baseline, BMI and HbA1c were 26.5 (24.6–30.1) and 8.3 (8.0–9.3), and 26.7 (25.0–30.0) kg/m 2 and 8.0 (7.6–8.9) %, in the CRD and LCD, respectively. At the end of the study, HbA1c decreased by −0.65 (−1.53 to −0.10) % in the LCD group, compared with 0.00 (−0.68 to 0.40) % in the CRD group (p 2 ] exceeded that observed in the CRD group (p = 0.03). Conclusions Our study demonstrated that 6-month 130 g/day LCD reduced HbA1c and BMI in poorly controlled Japanese patients with T2DM. LCD is a potentially useful nutrition therapy for Japanese patients who cannot adhere to CRD. This trial was registered at http://www.umin.ac.jp/english/ (University Hospital Medical Information Network: study ID number 000010663).

Background: This study aimed to investigate the preventive effects of tofogliflozin, a selective sodium-glucose cotransporter 2 (SGLT2) inhibitor, on atherosclerosis progression in type 2 diabetes (T2DM) patients without apparent cardiovascular disease (CVD) by monitoring carotid intima-media thickness (IMT). Methods: This prospective, randomized, open-label, blinded-endpoint, multicenter, parallel-group, comparative study included 340 subjects with T2DM but no history of apparent CVD recruited at 24 clinical units. Subjects were randomly allocated to either the tofogliflozin treatment group (n=169) or conventional treatment group using drugs other than SGLT2 inhibitors (n=171). Primary outcomes were changes in mean and maximum common carotid IMT measured by echography during a 104-week treatment period. Findings: Although the mean IMT of the common carotid artery (mean-IMT-CCA), along with the right and left maximum IMT of the CCA (max-IMT-CCA), statistically significantly declined in both the tofogliflozin (-0.132 mm, SE 0.007; -0.163 mm, SE 0.013; -0.170 mm, SE 0.020; respectively) and the control group (-0·140 mm, SE 0·006; -0·190 mm, SE 0·012; -0·190 mm, SE 0·020; respectively), no significant difference was observed between the two groups. Relative to the control treatment effects, tofogliflozin statistically significantly reduced the HbA1c, blood glucose level, body weight/body mass index, abdominal circumference, and systolic blood pressure, and statistically significantly increased the HDL-C. Interpretation: A tofogliflozin treatment regimen of 104 weeks was not associated with improved inhibition of carotid wall thickening in T2DM patients without apparent CVD, as compared to the effect of the control treatment. Trial Registration: UMIN000017607. Funding Statement: Kowa Co., Ltd., Tokyo, Japan. Declaration of Interests: Naoto Katakami is a staff member of the endowed chair established by funds from Kowa Co., Ltd., and has received research funds from MSD, and lecture fees from Astellas Pharma Inc., AstraZeneca K.K., Boehringer Ingelheim, Daiichi Sankyo Inc., Eli Lilly, Kowa Pharmaceutical Co., Kyowa Hakko Kirin Co. Ltd., Mitsubishi Tanabe Pharma Co., Novartis Pharmaceuticals, Novo Nordisk Pharma, Ono Pharmaceutical Co., Taisho Toyama Pharmaceutical Co., Takeda Pharmaceutical Co., and Sanofi-Aventis, and Shionogi & Co. Tomoya Mita has received lecture fees from Astellas Pharma Inc., Daiichi Sankyo Inc., Eli Lilly, Kowa Pharmaceutical Co., Kyowa Hakko Kirin Co. Ltd., Mitsubishi Tanabe Pharma Co., Novo Nordisk Pharma, Ono Pharmaceutical Co., Ltd., Takeda Pharmaceutical Company Limited and Sanofi-Aventis, scholarship donations from MSD K.K., Astellas Pharma Inc., AstraZeneca K.K., Ono Pharmaceutical Co., Ltd., Kyowa Hakko Kirin Co. Ltd., Sanofi-Aventis K.K., Daiichi Sankyo Company, Limited, Sumitomo Dainippon Pharma Co., Ltd., Takeda Pharmaceutical Company Limited, Mitsubishi Tanabe Pharma Corporation, Terumo Corporation, Nippon Boehringer Ingelheim Co., Ltd., Novo Nordisk Pharma Ltd., Pfizer Japan Inc., Benefit One Health Care Inc., Mochida Pharmaceutical Co., Ltd., and Nitto Boseki Co., Ltd. as well as funds of endowed chair from MSD K.K., Takeda Pharmaceutical Company Limited. Toshihiko Shiraiwa has received lecture fees from Sanofi-Aventis K.K. and Takeda Pharmaceutical Company Limited and research funding from Novo Nordisk Pharma Ltd., Sanofi-Aventis K.K., Takeda Pharmaceutical Company Limited, AstraZeneca K.K., Nippon Boehringer Ingelheim Co., Ltd., and Mitsubishi Tanabe Pharma Corporation. Tetsuyuki Yasuda has received lecture fees from Nippon Boehringer Ingelheim Co., Ltd. and Sanofi-Aventis K.K. Yosuke Okada has received lecture fees from Astellas Pharma Inc., MSD K.K., Ono Pharmaceutical Co., Ltd., Mitsubishi Tanabe Pharma Corporation, Bayer Holding Ltd., Novartis Pharmaceuticals Corp., Novo Nordisk Pharma Ltd., Eli Lilly Japan K.K., and Kissei Pharmaceutical Co., Ltd. as well as research funding from Kowa Pharmaceutical Co. Ltd. and Mitsubishi Tanabe Pharma Corporation. Hideaki Kaneto has received lecture fees from Nippon Boehringer Ingelheim Co., Ltd., Sanofi-Aventis K.K., Novo Nordisk Pharma Ltd., Eli Lilly Japan K.K., MSD K.K., Ono Pharmaceutical Co., Ltd., Takeda Pharmaceutical Company Limited, Daiichi Sankyo Company, Limited, Mitsubishi Tanabe Pharma Corporation, AstraZeneca K.K., Astellas Pharma Inc., Novartis Pharmaceuticals Corp., and Sumitomo Dainippon Pharma Co.; scholarship donations from Novo Nordisk Pharma Ltd., Nippon Boehringer Ingelheim Co., Ltd., Sumitomo Dainippon Pharma Co., Ltd., Ono Pharmaceutical Co., Ltd., Sanofi-Aventis K.K., Eli Lilly Japan K.K., Astellas Pharma Inc., Daiichi Sankyo Company, Limited, Mitsubishi Tanabe Pharma Corporation, MSD K.K., Takeda Pharmaceutical Company Limited, AstraZeneca K.K., Mochida Pharmaceutical Co., Ltd., Taisho Toyama Pharmaceutical Co., Kissei Pharmaceutical Co., Ltd., and Kyowa Hakko Kirin Co. Ltd; and research funding from Taisho Pharmaceutical Co., Sumitomo Dainippon Pharma Co. Takeshi Osonoi has received lecture fees from Takeda Pharmaceutical Company Limited, Astellas Pharma Inc., Novo Nordisk Pharma Ltd., and Sanwa Kagaku Kenkyusho Co., Ltd.; manuscript fees from Sanwa Kagaku Kenkyusho Co., Ltd.; and research funding from Takeda Pharmaceutical Company Limited, Novo Nordisk Pharma Ltd., Astellas Pharma Inc., Sanwa Kagaku Kenkyusho Co., Ltd., Mitsubishi Tanabe Pharma Corporation, Nippon Boehringer Ingelheim Co., Ltd., Taisho Pharmaceutical Co., Ltd., Eli Lilly Japan K.K., Daiichi Sankyo Company, Limited, Bayer Holding Ltd., Kowa Pharmaceutical Co. Ltd., and AbbVie Inc. Nobuichi Kuribayashi has received lecture fees from Takeda Pharmaceutical Company Limited, Sanofi-Aventis K.K., Novo Nordisk Pharma Ltd., MSD K.K., and Mitsubishi Tanabe Pharma Corporation. Satoru Sumitani has received lecture fees from Sumitomo Dainippon Pharma Co., Ltd. Yasunori Sato has received lecture fees from Mochida Pharmaceutical Co., Ltd. Hirotaka Watada has received lecture fees from Sumitomo Dainippon Pharma CO., Ltd., Bayer Yakuhin, Ltd. Sanofi-Aventis K.K., MSD K.K., Astellas Pharma Inc., Takeda Pharmaceutical Company Ltd, Mitsubishi Tanabe Pharma Co., AstraZeneca K.K., Nippon Boehringer Ingelheim Co., Ltd., Eli Lilly Japan K.K., Novo Nordisk Pharma Ltd., Sanwa Kagaku Kenkyusho Co., Ltd., Kowa Co., Ltd., Novartis Pharmaceuticals Corp., Daiichi Sankyo Company, Ltd, Kyowa Hakko Kirin Co. Ltd., Ono Pharmaceutical Co., Ltd., and Kissei Pharmaceutical Co., Ltd. and research support from Novartis Pharmaceuticals Corp., Otsuka Pharmaceutical Co., Ltd., Eli Lilly Japan K.K., MSD K.K., Astellas Pharma Inc., Bayer Yakuhin, Ltd. Teijin Pharma Ltd., Ono Pharmaceutical Co., Ltd., Kissei Pharmaceutical Co., Ltd., Kyowa Hakko Kirin Co. Ltd., Kowa Pharmaceutical Co. Ltd., Sanofi-Aventis K.K., Sanwa Kagaku Kenkyusho Co., Ltd., Daiichi Sankyo Company, Ltd, Sumitomo Dainippon Pharma Co., Ltd., Taisho Toyama Pharmaceutical Co., Ltd., Takeda Pharmaceutical Company Ltd, Mitsubishi Tanabe Pharma Corporation, Nippon Boehringer Ingelheim Co., Ltd., Novo Nordisk Pharma Ltd., Pfizer Japan Inc., Shionogi & Co., Ltd. Yakult, and Kissei Pharmaceutical Co., Ltd. Iichiro Shimomura has received lecture fees from Astellas Pharma Inc., AstraZeneca K.K., MSD K.K., Ono Pharmaceutical Co., Kyowa Kirin Co., Ltd., Kowa Company, Ltd., Sanofi K.K., Sanwa Kagaku Kenkyusho Co., Daiichi Sankyo Co., Takeda Pharma K.K., Mitsubishi Tanabe Pharma Co., Teijin Pharma, Eli Lilly Japan K.K., Nippon Boehringer Ingelheim Co., Novartis Pharma K.K., Novo Nordisk Pharma, Mochida Pharmaceutical Co., Taisho Pharmaceutical Co. Ltd., Nippon Chemiphar Co., Ltd., Covidien Japan Inc., Amgen Astellas Biopharma K.K., KOBAYASHI Pharmaceutical Co., Ltd., Dainippon Sumitomo Pharma Co., Rohto Pharmaceutical Co., Ltd.; and research funds from Astellas Pharma Inc., MSD K.K, Ono Pharmaceutical Co., Kaken Pharmaceutical Co., Kyowa Kirin Co., Ltd., Sanofi K.K., Shionogi & Co., Daiichi Sankyo Co., Dainippon Sumitomo Pharma Co., Takeda Pharma K.K., Mitsubishi Tanabe Pharma Co., Teijin Pharma, Novartis Pharma K.K., Novo Nordisk Pharma, Eli Lilly Japan K.K, Kowa Company, Ltd.; and consulting fees from AstraZeneca K.K., MSD K.K., Taisho Pharmaceutical Co. Ltd., Novo Nordisk Pharma, Lotte Co., Ltd. Hidenori Yoshii, Yutaka Umayahara, Tsunehiko Yamamoto, Kazuhisa Maeda, Hiroki Yokoyama, Keisuke Kosugi, Kentaro Ohtoshi, Isao Hayashi, Mamiko Tsugawa, Kayoko Ryomoto, Hideki Taki, Tadashi Nakamura, and Satoshi Kawashima declare that they have no conflict of interest. Ethics Approval Statement: All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1964, as revised in 2013. Informed consent was obtained from all patients for being included in the study.

Aims Olfactory dysfunction is associated with the transition from normal cognition to dementia in persons without type 2 diabetes. This study aimed to investigate whether olfactory dysfunction could be an early marker of future dementia in older patients with type 2 diabetes. Methods This exploratory study included 151 older Japanese outpatients with type 2 diabetes who did not have a diagnosis of probable dementia at baseline. A multivariate logistic regression model was used to determine whether Open Essence (OE) test score at baseline is associated with the development of probable dementia. Results Over 3 years, approximately 9% of the study subjects developed probable dementia. Subjects with olfactory dysfunction at baseline developed probable dementia more frequently than those without. Multivariate logistic regression showed that lower OE test score, higher age, lower Mini-Mental State Examination (MMSE) score, higher total protein concentration, and more frequent use of a sulfonylurea are significantly associated with the development of probable dementia. Stepwise multivariate regression analysis demonstrated that change in OE test score over 3 years is significantly associated with change in MMSE score. Conclusions Our study suggested that olfactory dysfunction precedes the development of probable dementia in older patients with type 2 diabetes.

Background Lipoprotein-X (Lp-X) is an abnormal phospholipid-rich lipoprotein found in patients with cholestatic liver disease. Some patients exhibit skin xanthomas and severe hyperlipidemia. Objective We investigated whether Lp-X induces foam cell formation in human-derived macrophages. Methods To compare the atherogenic properties of Lp-X and modified LDL, we isolated Lp-X from 2 patients who had drug-induced cholestasis and xanthoma striata in the interphalangeal folds. We prepared oxidized LDL and acetylated LDL from healthy volunteers for the positive control experiments. Results When human monocyte-derived macrophages were incubated with these lipoproteins, the isolated Lp-X induced more prominent lipid accumulation than oxidized LDL or acetylated LDL. One case underwent liver biopsy, with the bile ducts showing marked damage, fulfilling the criteria for vanishing bile duct syndrome. The other case was clinically diagnosed as drug-induced hypersensitivity syndrome. In both cases, Lp-X levels decreased markedly and the xanthomas disappeared completely after the improvement of cholestasis. Conclusion This study indicates that Lp-X induces foam cell formation in human-derived macrophages. Our findings strongly suggest that persistently elevated Lp-X may cause xanthomas.

To compare the efficacy on glycemic parameters between a 12-week administration of once-daily linagliptin and thrice-daily voglibose in Japanese patients with type 2 diabetes.In a multi-center, randomized, parallel-group study, 382 patients with diabetes were randomized to the linagliptin group (n=192) or the voglibose group (n=190). A meal tolerance test was performed at weeks 0 and 12. Primary outcomes were the change from baseline to week 12 in serum glucose levels at 2h during the meal tolerance test, HbA1c levels, and serum fasting glucose levels, which were compared between the 2 groups.Whereas changes in serum glucose levels at 2h during the meal tolerance test did not differ between the groups, the mean change in HbA1c levels from baseline to week 12 in the linagliptin group (-0.5±0.5% [-5.1±5.4mmol/mol]) was significantly larger than in the voglibose group (-0.2±0.5% [-2.7±5.4mmol/mol]). In addition, there was significant difference in changes in serum fasting glucose levels (-0.51±0.95mmol/L in the linagliptin group vs. -0.18±0.92mmol/L in the voglibose group, P0.001). The incidences of hypoglycemia, serious adverse events (AEs), and discontinuations due to AEs were low and similar in both groups. However, gastrointestinal AEs were significantly lower in the linagliptin group (1.05% vs. 5.85%; P=0.01).These data suggested that linagliptin monotherapy had a stronger glucose-lowering effect than voglibose monotherapy with respect to HbA1c and serum fasting glucose levels, but not serum glucose levels 2h after the start of the meal tolerance test.

A single bout of exercise is known to increase the insulin sensitivity of skeletal muscle; however, the underlying mechanism of this phenomenon is not fully understood. Because a single bout of exercise induces a transient increase in blood interleukin-6 (IL-6) level, we hypothesized that the enhancement of insulin sensitivity after a single bout of exercise in skeletal muscle is mediated at least in part through IL-6-dependent mechanisms. To test this hypothesis, C57BL6J mice were intravenously injected with normal IgG or an IL-6 neutralizing antibody before exercise. Twenty-four hours after a single bout of exercise, the plantaris muscle was harvested to measure insulin sensitivity and glucose transporter (GLUT)-4 expression levels by ex-vivo insulin-stimulated 2-deoxyglucose (2-DG) uptake and Western blotting, respectively. Compared with sedentary mice, mice that performed exercise showed enhanced IL-6 concentration, insulin-stimulated 2-DG uptake, and GLUT-4 expression in the plantaris muscle. The enhanced insulin sensitivity and GLUT4 expression were canceled by injection of the IL-6 neutralizing antibody before exercise. In addition, IL-6 injection increased GLUT4 expression, both in the plantaris muscle and the soleus muscle in C57BL6J mice. Furthermore, a short period of incubation with IL-6 increased GLUT4 expression in differentiated C2C12 myotubes. In summary, these results suggested that IL-6 increased GLUT4 expression in muscle and that this phenomenon may play a role in the post-exercise enhancement of insulin sensitivity in skeletal muscle.

Glucagon-like peptide 1 (GLP-1) has been shown to play important roles in maintaining β-cell functions, such as insulin secretion and proliferation. While expression levels of GLP-1 receptor (Glp1r) are compromised in the islets of diabetic rodents, it remains unclear when and to what degree Glp1r mRNA levels are decreased during the progression of diabetes. In this study, we performed real-time PCR with the islets of db/db diabetic mice at different ages, and found that the expression levels of Glp1r were comparable to those of the islets of nondiabetic db/misty controls at the age of four weeks, and were significantly decreased at the age of eight and 12 weeks. To investigate whether restored expression of Glp1r affects the diabetic phenotypes, we generated the transgenic mouse model Pdx1(PB)-CreER(TM); CAG-CAT-Glp1r (βGlp1r) that allows for induction of Glp1r expression specifically in β cells. Whereas the expression of exogenous Glp1r had no measurable effect on glucose tolerance in nondiabetic βGlp1r;db/misty mice, βGlp1r;db/db mice exhibited higher glucose and lower insulin levels in blood on glucose challenge test than control db/db littermates. In contrast, four weeks of treatment with exendin-4 improved the glucose profiles and increased serum insulin levels in βGlp1r;db/db mice, to significantly higher levels than those in control db/db mice. These differential effects of exogenous Glp1r in nondiabetic and diabetic mice suggest that downregulation of Glp1r might be required to slow the progression of β-cell failure under diabetic conditions.

Pancreatic β-cell mass is known to be considerably altered during pregnancy and after parturition in rodents and humans. Although βcell mass is increased during pregnancy and starts to return toward its original level shortly after parturition, the cellular mechanisms by which β-cell mass during this period is regulated remains unclear. To address this issue in mice, we quantified β-cell mass and investigated the mechanisms underlying its regulation throughout the perinatal and postpartum period. The increased β-cell size and proliferation during pregnancy were significantly reduced shortly after parturition, whereas there was no evidence of β-cell reprogramming or increased apoptosis. Direct RNA sequencing of islets from pregnant and postpartum mice demonstrated dynamic changes in gene expression patterns, showing robust down-regulation of cell cycle-related genes 1 day after parturition, and the biphasic up-regulation of serotonin metabolism-related genes during pregnancy and at postpartum day 7. Serotonin synthesis was activated during lactation in human as well as in mice. Taken together, these findings demonstrate that β-cell mass is decreased shortly after parturition owing to reduced β-cell size and proliferation, and is subsequently increased, in association with lactation and serotonin biosynthesis. Funding Statement: This work was supported by research grant for Cross-disciplinary Collaboration, Juntendo University 2017 (29-35). Declaration of Interests: The authors stated: "There is no conflict of interest on this study." Ethics Approval Statement: The study design was approved by the ethics committee of the Hirosaki University School of Medicine (approval number 2014-269), and the study conforms to the provision of the Declaration of Helsinki.

Background: Physical inactivity impairs muscle insulin sensitivity. However, its mechanism is unclear. Methods: To model physical inactivity, we applied 24-h hind-limb cast immobilization (HCI) to mice with normal or high fat diet (HFD), and evaluated intramyocellular lipids and the insulin signaling pathway in the soleus muscle. Findings: While 2-wk HFD alone did not alter intramyocellular diacylglycerol (IMDG) accumulation, HCI alone increased it by 1.9-fold and HCI after HFD further increased it by 3.3-fold. Parallel to this, we found increased PKCe activity, reduced insulin-induced 2-deoxy-glucose (2-DOG) uptake, and reduced phosphorylation of IRβ and Akt, key molecules for insulin signaling pathway. Lipin1, which converts phosphatidic acid to diacylglycerol, showed enhanced by HCI, and dominant-negative lipin1 expression in muscle prevented HCI-induced IMDG accumulation and impaired insulin-induced 2-DOG uptake. Further, 24-h leg cast immobilization in human increased lipin1 expression. Interpretation: Even short-term immobilization increases IMDG and impairs insulin sensitivity in muscle via enhanced lipin1 activity. Funding Statement: This work was supported by High Technology Research Center Grant, Strategic Research Foundation at Private Universities and KAKENHI (Grant-in-Aid for Scientific Research (C)) (15K01729) from the Ministry of Education, Culture, Sports, Science, and Technology of Japan. Declaration of Interests: All authors declare no conflict of interest. Ethics Approval Statement: All subjects gave written informed consent to participate in the study, which was approved by the ethics committee of Juntendo University. This study was carried out in accordance with the principles outlined in the Declaration of Helsinki. The present study complied with the principles and guidelines of the Japanese Council on Animal Care, and it was also approved by the Committee for Animal Research of Juntendo University.

Aims Recent clinical studies identified the relation between olfactory dysfunction and cognitive impairment in the elderly without type 2 diabetes mellitus. The aim of the present study was to define the relation between olfactory function and cognition in elderly patients with type 2 diabetes mellitus. Methods The study participants comprised 250 elderly (age, 68–77, median 72) Japanese outpatient with type 2 diabetes mellitus free of clinically-evident cognitive impairment. Olfactory and cognitive functions were evaluated by the Open Essence (OE) test and Mini-mental State Examination (MMSE), respectively. Results Based on the MMSE score, 62.0%, 24.4%, and 13.6% of the participants were considered to have no impairment, possible cognitive impairment and probable dementia, respectively. The OE test score of the probable dementia group was significantly lower than other groups. Furthermore, age and serum uric acid were significantly higher in the probable dementia group than other groups. Simple correlation analysis showed positive correlation between the MMSE score and diastolic blood pressure, education, OE test score, total cholesterol, LDL cholesterol, folic acid, and negative correlation with age, HbA 1c , aspartate aminotransferase, serum adiponectin and urinary albumin excretion. Multivariate regression analysis showed that OE test score correlated significantly and independently with MMSE score (standardized coefficients β = 0.542, R 2 = 0.478, P Conclusions The results suggested the association of olfactory dysfunction with cognitive impairment in elderly patients with type 2 diabetes mellitus.

SummaryEndothelial dysfunction is a central hallmark of diabetes. The transcriptional coactivator PGC-1α is a powerful regulator of metabolism, but its role in endothelial cells remains poorly understood. We show here that endothelial PGC-1α expression is high in diabetic rodents and humans and that PGC-1α powerfully blocks endothelial migration in cell culture and vasculogenesis in vivo. Mechanistically, PGC-1α induces Notch signaling, blunts activation of Rac/Akt/eNOS signaling, and renders endothelial cells unresponsive to established angiogenic factors. Transgenic overexpression of PGC-1α in the endothelium mimics multiple diabetic phenotypes, including aberrant re-endothelialization after carotid injury, blunted wound healing, and reduced blood flow recovery after hindlimb ischemia. Conversely, deletion of endothelial PGC-1α rescues the blunted wound healing and recovery from hindlimb ischemia seen in type 1 and type 2 diabetes. Endothelial PGC-1α thus potently inhibits endothelial function and angiogenesis, and induction of endothelial PGC-1α contributes to multiple aspects of vascular dysfunction in diabetes.

The aim of this retrospective study was to investigate the relationship between progression of carotid intima-media thickness (cIMT) and cardiovascular events in Japanese patients with type 2 diabetes mellitus (T2DM) and free of history of cardiovascular events.Patients with T2DM (n=342) without history of cardiovascular events whose cIMT was assessed more than twice by ultrasonography were recruited and followed up for cardiovascular events.During a mean follow-up of 7.6 years, 56 (16.4%) cardiovascular events (27 coronary events and 29 cerebrovascular events) were recorded. Multivariate analysis with the Cox proportional hazard model identified cIMT progression as a significant determinant of cardiovascular events, with a hazard ratio (HR) of 2.24 (95% confidence interval; CI, 1.25-4.03, P0.01), in addition to baseline cIMT. The Kaplan-Meier curves also showed significantly higher event rate in patients with high cIMT progression compared with those with low cIMT progression (log-rank χ(2)=6.65; P0.01). Furthermore, the combination of high baseline cIMT and high cIMT progression was a significant predictor of cardiovascular events.Our findings suggest that cIMT progression, in addition to baseline cIMT, is a predictor of cardiovascular events in patients with T2DM without history of cardiovascular events, and that the combination of cIMT progression and baseline cIMT has a strong predictive power for such events.

It is likely that the C allele of the polymorphism at position 29 of the translated sequence of transforming growth factor (TGF)-β1 gene, which codes a pleiotropic cytokine expressed in a variety of cells, is a susceptibility allele for cerebral infarction in Japanese type 2 diabetic patients.

Glucagon-like peptide-1 is a hormone secreted by L cells of the small intestine and stimulates glucose-dependent insulin response. Glucagon-like peptide-1 receptor agonists such as exendin-4 are currently used in type 2 diabetes, and considered to have beneficial effects on the cardiovascular system. To further elucidate the effect of glucagon-like peptide-1 receptor agonists on cardiovascular diseases, we investigated the effects of exendin-4 on intimal thickening after endothelial injury. Under continuous infusion of exendin-4 at 24 nmol/kg/day, C57BL/6 mice were subjected to endothelial denudation injury of the femoral artery. Treatment of mice with exendin-4 reduced neointimal formation at 4weeks after arterial injury without altering body weight or various metabolic parameters. In addition, in vitro studies of isolated murine, rat and human aortic vascular smooth muscle cells showed the expression of GLP-1 receptor. The addition of 10nM exendin-4 to cultured smooth muscle cells significantly reduced their proliferation induced by platelet-derived growth factor. Our results suggested that exendin-4 reduced intimal thickening after vascular injury at least in part by the suppression of platelet-derived growth factor-induced smooth muscle cells proliferation.

Beta-cell proliferation is regulated by various metabolic demands including peripheral insulin resistance, obesity, and hyperglycemia. In addition to enhancement of glucose-induced insulin secretion, agonists for glucagon-like peptide-1 receptor (GLP-1R) stimulate proliferation and inhibit apoptosis of beta-cells, thereby probably preserve beta-cell mass. To evaluate the beta-cell preserving actions of GLP-1R agonists, we assessed the acute and chronic effects of exendin-4 on beta-cell proliferation, mass and glucose tolerance in C57BL/6J mice under various conditions. Short-term administration of high-dose exendin-4 transiently stimulated beta-cell proliferation. Comparative transcriptomic analysis showed upregulation of IGF-1 receptor and its downstream effectors in islets. Treatment of mice with exendin-4 daily for 4 weeks (long-term administration) and feeding high-fat diet resulted in significant inhibition of weight gain and improvement of glucose tolerance with reduced insulin secretion and beta-cell mass. These findings suggest that long-term GLP-1 treatment results in insulin sensitization of peripheral organs, rather than enhancement of beta-cell proliferation and function, particularly when animals are fed high-fat diet. Thus, the effects of exendin-4 on glucose tolerance, insulin secretion, and beta-cell proliferation largely depend on treatment dose, duration of treatment and meal contents. While GLP-1 enhances proliferation of beta-cells in some diabetic mice models, our results suggest that GLP-1 stimulates beta-cell growth only when expansion of beta-cell mass is required to meet metabolic demands.

To our knowledge, there is currently no insulin infusion protocol for critically ill patients especially designed for Asian diabetics although many such protocols are used in Western countries. In this study, we modified the Yale insulin infusion protocol taking into consideration the characteristics of Japanese diabetics and hospital environment. We tested the modified protocol in 40 type 2 diabetic patients after elective open-heart surgery (MY group) comparing with 35 type 2 diabetic patients under empirical blood glucose control (EC group). Analyses of 1656 blood glucose measurements during insulin infusion revealed that percentage of samples that showed achievement of target blood glucose level (80-140 mg/dl) was higher under MY (78+/-15%, n=870) than EC (57+/-23%, n=786, p0.0001). On the other hand, the percentage of samples in which blood glucose was less than 60 mg/dl was comparable in the two groups (MY: 0.5+/-5.9 per thousand, EC: 5.1+/-18.5 per thousand). None of the patients with hypoglycemia showed significant clinical adverse effects. In conclusion, our modified Yale insulin infusion protocol is effective and safe for tight blood glucose control in Japanese diabetic patients after open-heart surgery.

The effect of short-term fat loading on intramyocellular lipid (IMCL) in different types of muscle in endurance runners and sprinters has not been fully elucidated yet. The purpose of this study was to investigate the effect of dietary lipid on IMCL in soleus muscle (SOL) and tibialis anterior muscle (TA) during training period in endurance runners and sprinters. Seven male endurance runners and 7 male sprinters were selected to participate in the study. We measured TA- and SOL-IMCL levels after 3-day course of isocaloric normal- (25%), high- (60%), and low-fat (10%) diet during training period by (1)H-magnetic resonance spectroscopy in each subject. In sprinters, TA- and SOL-IMCL levels were comparable after each diet protocol. However, in endurance runners, TA-IMCL levels after normal-fat and high-fat diets were 1.7 times and 3.0 times higher than that after low-fat diet, respectively. The SOL-IMCL values after normal-fat diet and high-fat diet were 1.5 times and 1.6 times higher than that after low-fat diet, respectively. In addition, the TA-IMCL level after high-fat diet, but not SOL-IMCL, was significantly higher compared with that after normal-fat diet. Our data suggested that short-term dietary fat challenge during training period significantly altered IMCL level in endurance runners, but not in sprinters. In addition, response to fat loading on IMCL was influenced by variation of muscle type in endurance runners. These phenotypic and regional differences might be explained by differences in type of exercise training and muscle fiber composition.

The aim of this study was to investigate the effect of fluctuations in blood glucose levels on atherogenesis. Apolipoprotein (apo) E-deficient mice fed maltose twice daily were used as a model of repetitive postprandial glucose spikes. We investigated the number of macrophages adherent to the endothelium and the area of fibrotic arteriosclerotic lesions, with and without administration of miglitol, an alpha-glucosidase inhibitor. Macrophage adhesion to endothelial cells in thoracic aorta was quantitated by the en face method for optimal observation of endothelial surface after immunohistochemical staining for Mac-2. The area of arteriosclerotic lesions was measured in elastica van Giesson-stained proximal aorta. The number of adherent macrophages increased at 1 week after commencement of maltose feeding and the size of arteriosclerotic lesion increased at 5 weeks after such feeding. These increases were prevented by simultaneous use of miglitol. Our data demonstrated that glucose fluctuations accelerate atherogenesis. This was independent of changes in serum cholesterol level in vivo. Reduction of glucose fluctuation by alpha-glucosidase inhibitor efficiently controlled the progression of atherosclerosis.

To investigate the effect of highly purified eicosapentaenoic acid (EPA) on the progression of diabetic macroangiopathy, we performed an open-label randomized prospective trial. A total of 81 Japanese type 2 diabetes were randomly assigned to the EPA (1800 mg/day) treated group or the control group. Carotid intima-media thickness (IMT) and brachial-ankle pulse wave velocity (baPWV) were evaluated before and after treatment in both groups. Sixty patients (EPA group, n=30; control group, n=30) completed this study. During the study period of 2.1+/-0.2 years, the mean IMT and max IMT of the EPA treated group showed a significant annual decrease compared with that of the control group (mean IMT, -0.029+/-0.112 mm versus 0.016+/-0.109 mm, respectively, P=0.029; max IMT, -0.084+/-0.113 mm versus -0.005+/-0.108 mm, respectively, P=0.0008). The baPWV was also improved significantly in the EPA treated group compared with the control group (-22.1+/-127.9 cm/s versus 62.3+/-223 cm/s, respectively, P=0.021). Multiple regression analysis showed that the administration of EPA was a significant and independent factor associated with an annual improvement of mean IMT (R2=0.067). In summary, this is the first demonstration that administration of purified EPA improves the carotid IMT and the baPWV in patients with type 2 diabetes.

To date, the potency of pancreatic and duodenal homeobox gene 1 (PDX-1) in inducing differentiation into insulin-producing cells has been demonstrated in some cells and tissues. In order to carry out efficient screening of somatic tissues and cells that can transdifferentiate into beta-cell-like cells in response to PDX-1, we generated CAG-CAT-PDX1 transgenic mice carrying a transgene cassette composed of the chicken beta-actin gene (CAG) promoter and a floxed stuffer DNA sequence (CAT) linked to PDX-1 cDNA. When the mice were crossed with Alb-Cre mice, which express the Cre recombinase driven by the rat albumin gene promoter, PDX-1 was expressed in more than 50% of hepatocytes and cholangiocytes. The PDX-1 (+) livers expressed a variety of endocrine hormone genes such as insulin, glucagon, somatostatin, and pancreatic polypeptide. In addition, they expressed exocrine genes such as elastase-1 and chymotrypsinogen 1B. However, the mice exhibited marked jaundice due to conjugated hyperbilirubinemia, and the liver tissue displayed abnormal lobe structures and multiple cystic lesions. Thus, the in vivo ectopic expression of PDX-1 in albumin-producing cells was able to initiate but not complete the differentiation of liver cells into pancreatic cells. The conditional PDX-1 transgenic mouse system developed in this study appeared to be useful for efficient screening of PDX-1 responsive somatic tissues and cells.

Endothelial damage is considered to be an initial change in the atherosclerotic process. However, it has been difficult to detect this initial change in vivo. We established a modified En face immunostaining method that enabled us to obtain clear images of the entire endothelial surface, including at arterial bifurcations, and to quantitate the number of cells of interest in the endothelium. Using this method, we found that treatment with an atherogenic factor, albumin-derived advanced glycosylation end products, for only 2 weeks caused a significant increase in the number of proliferating cell nuclear antigen-positive endothelial cells and the number of macrophages adhering to the endothelium, suggesting that these changes might be relevant to the early events of endothelial dysfunction. In conclusion, the present modified En face immunostaining method may be a promising tool for understanding the pathophysiology of atherosclerosis.

Homeodomain transcription factor Nkx2.2 is required for the final differentiation of the beta-cells in the pancreas and for the production of insulin. Nkx2.2 is expressed in islet cell precursors during pancreatic development and persists in a subset of mature islet cells including all beta-cells. To understand the mechanisms regulating the expression of Nkx2.2 in these different cell populations, we outlined the structure of the mouse nkx2.2 gene and identified regions that direct cell type-specific expression. The nkx2.2 gene has two noncoding alternative first exons (exons 1a and 1b). In transgenic mice, sequences upstream from exon 1a directed expression predominantly in mature islet cells. Within this exon 1a promoter, cooperative interactions between HNF3 and basic helix-loop-helix factors neurogenin-3 or NeuroD1 binding to adjacent sites played key roles in its islet cell-specific expression. In contrast, sequences upstream from exon 1b restricted expression specifically to islet cell precursors. These studies reveal distinct mechanisms for directing the expression of a key differentiation factor in precursors versus mature islet cells.

Background: We previously reported that the carotid artery intima-media thickness (IMT) increased with age and that patients with type 2 diabetes mellitus (DM) had a significantly larger IMT than did age-matched nondiabetic subjects with normal glucose tolerance. Although the exact mechanism behind the increase in IMT in diabetic patients has not been determined, data obtained from in vivo and in vitro studies suggest that hyperglycemia-induced oxidative stress may lead to atherogenesis. Objective: The aim of this single-center study was to determine whether long-term oxidative stress and the carotid IMT are influenced by differences of the angiotensin-converting enzyme insertion/deletion ( ACE I/D ) and NADPH (nicotinamide adenine dinucleotide phosphate, reduced form) oxidase p22phox C242T genotypes. Methods: Eligible subjects were Japanese patients with type 2 DM. Polymorphism of the ACE I/D and p22phox gene was investigated using polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism, respectively. The rate of an acquired mutation of mitochondrial DNA—that is, A-to-G substitution at position 3243 (mtDNA A3243G )—was determined by real-time PCR. As a marker of early atherosclerosis, the carotid artery IMT was measured using high-resolution B-mode ultrasonography. Results: A total of 262 Japanese patients (173 men, 89 women; mean [SEM] age, 58 [0.6] years [range, 18–80 years]) were recruited and enrolled for study. An ACE D - positive ( DD or DI ) and p22phox 242T -negative genotype ( CC ) was associated with a significantly higher mtDNA A3243G mutation rate than the other 3 possible genotypes (0.0219% [0.0028%] vs 0.0097% [0.0012%]; P P Conclusion: In this study, the ACE D - positive and p22phox 242T -negative genotype showed higher rates of somatic mtDNA mutation (mtDNA A3243G ) and higher carotid mean and maximum IMT levels.

Oxidative stress is induced under diabetic conditions and causes various forms of tissue damage in patients with diabetes. Recently, pancreatic beta-cells have emerged as a putative target of oxidative stress-induced tissue damage and this seems to explain in part the progressive deterioration of beta-cell function in type 2 diabetes. As a step toward clinical trial of antioxidant for type 2 diabetes, we investigated the possible anti-diabetic effects of probucol, an antioxidant widely used as an anti-hyperlipidemic agent, on preservation of beta-cell function in diabetic C57BL/KsJ-db/db mice. Probucol-containing diet was given to mice from 6 to 16 weeks of age. Immunostaining for oxidative stress markers such as 4-hydroxy-2-nonenal (HNE)-modified proteins and heme oxygenase-1 revealed that probucol treatment decreased reactive oxygen species (ROS) in pancreatic islets of diabetic animals. Oxidative stress is known to enhance apoptosis of beta-cells and to suppress insulin biosynthesis, but probucol treatment led to preservation of beta-cell mass and the insulin content. According to intraperitoneal glucose tolerance tests, the probucol treatment preserved glucose-stimulated insulin secretion and improved glucose tolerance at 10 and 16 weeks: insulin, 280+/-82 vs. 914+/-238 pmol/l (120 min, at 16 weeks; P

During pancreatic development, the paired homeodomain transcription factor PAX4 is required for the differentiation of the insulin-producing beta cells and somatostatin-producing delta cells. To establish the position of PAX4 in the hierarchy of factors controlling islet cell development, we examined the control of the human PAX4 gene promoter. In both cell lines and transgenic animals, a 4.9-kilobase pair region directly upstream of the human PAX4 gene transcriptional start site acts as a potent pancreas-specific promoter. Deletion mapping experiments demonstrate that a 118-base pair region lying approximately 1.9 kilobase pairs upstream of the transcription start site is both necessary and sufficient to direct pancreas-specific expression. Serial deletions through this region reveal the presence of positive elements that bind several pancreatic transcription factors as follows: the POU homeodomain factor HNF1alpha, the orphan nuclear receptor HNF4alpha, the homeodomain factor PDX1, and a heterodimer composed of two basic helix-loop-helix factors. Interestingly, mutations in the genes encoding four of these factors cause a dominantly inherited form of human diabetes called Maturity Onset Diabetes of the Young. In addition, PAX4 itself has at least two high affinity binding sites within the promoter through which it exerts a strong negative autoregulatory effect. Together, these results suggest a model in which PAX4 expression is activated during pancreatic development by a combination of pancreas-specific factors but is then switched off once PAX4 protein reaches sufficient levels.

In the mature pancreas, the homeodomain transcription factor Nkx6.1 is uniquely restricted to beta-cells. Nkx6.1 also is expressed in developing beta-cells and plays an essential role in their differentiation. Among cell lines, both beta- and alpha-cell lines express nkx6.1 mRNA; but no protein can be detected in the alpha-cell lines, suggesting that post-transcriptional regulation contributes to the restriction of Nkx6.1 to beta-cells. To investigate the regulator of Nkx6.1 expression, we outlined the structure of the mouse nkx6.1 gene, and we identified regions that direct cell type-specific expression. The nkx6.1 gene has a long 5'-untranslated region (5'-UTR) downstream of a cluster of transcription start sites. nkx6.1 gene sequences from -5.6 to +1.0 kilobase pairs have specific promoter activity in beta-cell lines but not in NIH3T3 cells. This activity is dependent on sequences located at about -800 base pairs and on the 5'-UTR. Electrophoretic mobility shift assays demonstrate that homeodomain transcription factors PDX1 and Nkx2.2 can bind to the sequence element located at -800 base pairs. In addition, dicistronic assays establish that the 5'-UTR region functions as a potent internal ribosomal entry site, providing cell type-specific regulation of translation. These data demonstrate that complex regulation of both Nkx6.1 transcription and translation provides the specificity of expression required during pancreas development.

beta-Cell differentiation factor Nkx6.1 is a homeodomain protein expressed in developing and mature beta-cells in the pancreatic islets of Langerhans. To understand how it contributes to beta-cell development and function, we characterized its DNA binding and transactivation properties. A single copy of the homeodomain of Nkx6. 1 binds to a strictly conserved 8-base pair DNA consensus sequence, TTAATTAC; even minor variations to this consensus reduce DNA binding affinity significantly. Full-length Nkx6.1, however, has markedly reduced DNA binding affinity due to an acidic domain at the carboxyl end of the molecule that functions as a mobile binding interference domain capable of interrupting the interaction between DNA and DNA binding domains of the helix-turn-helix type. When expressed in fibroblast cell lines, Nkx6.1 represses transcription through isolated Nkx6.1 binding sites; in beta-cell lines, Nkx6.1 specifically represses the intact insulin promoter through TAAT-containing sequences. In Gal4 one-hybrid fusion studies, transcriptional repression maps to a discreet region within the amino terminus. Our findings suggest a model in which Nkx6.1, regulated by interactions through its carboxyl terminus, directs the repression of specific genes in developing and mature beta-cells.

Intensive insulin therapy composed of bolus and basal insulin has been believed as the most powerful recipe for glycemic control of both type 1 and type 2 diabetes. In this study, we investigated the effects of changes in basal/total daily insulin ratio (B/TD ratio) in type 2 diabetes patients on intensive insulin therapy including insulin glargine. The B/TD ratio used in our Japanese patients was about 0.35, and the ratio was increased up to about 0.46+/-0.12 without change of total insulin daily dose. After 24-week-treatment, mean glycated albumin of the patients whose B/TD ratio was increased was significantly lower than those of the patients whose B/TD ratio was not changed. Our results suggest that adequate supplementation of basal insulin may be important for maximum effect of bolus insulin even in Japanese who have serious defect in postprandial rapid insulin secretion.

The development of the pancreas appears to be regulated by various growth factors. We report here the expression of heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF) in the developing pancreas. Immunostaining of fetal and neonatal rat pancreata, in which endocrine cells are visible as cell clusters often associated with primitive ducts or ductular cells, revealed that most of the cluster-forming cells and primitive ducts or ductular cells express HB-EGF protein. In contrast, the exocrine pancreas lacked HB-EGF expression. Based on findings that the expression pattern was similar to that of the homeodomain-containing transcription factor PDX-1 (IDX-1/STF-1/IPF1) and that the regulatory region of the HB-EGF gene contained sequences similar to the PDX-1-binding A element, we examined whether PDX-1 could be a potential activator of HB-EGF gene expression. The results of reporter gene analyses suggested that the HB-EGF gene promoter is PDX-1-responsive and that the activity of the promoter in pancreatic beta cell-derived βTC1 cells depends on the PDX-1 binding site-like sequences. Gel-mobility shift analyses using an anti-PDX-1 antibody indicated that PDX-1 is a specific and dominant binding factor for an A element-like sequence in the HB-EGF gene. These observations suggest the possible involvement of HB-EGF in pancreas development. While PDX-1 is essential for pancreas development, HB-EGF may function as a mediator of PDX-1 and thus be involved in the development of the endocrine pancreas.

Cyclic ADP-ribose (cADPR), a well-known stimulator of ca(2+) release from the intracellular Ca(2+) pool, has recently emerged as a potential regulator of insulin secretion in pancreatic beta cells. As recently described, BST-1 is a glycosyl-phosphatidylinositol (GPI)-anchored surface molecule that exhibits homology with CD38 and Aplysia ADP-ribosyl cyclase. Like CD38, BST-1 has both ADP-ribosyl cyclase and cADPR hydrolase activities. As a step toward elucidating the physiological role of cADPR in insulin secretion we examined whether BST-1 is expressed in pancreatic islet cells. Sensitive reverse transcription-polymerase chain reaction detected almost as abundant expression of BST-1 mRNA in pancreatic islets as CD38 mRNA. Immunohistochemical analyses utilizing mirror image sections revealed that BST-1 protein is expressed in a majority of the cells in pancreatic islets and that at least beta cells and, to an even greater extent, alpha cells express BST-1. These observations suggest the involvement of multiple enzymes in the regulation of cADPR concentrations in pancreatic islet cells.