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We herein report the case of a 41-year-old Japanese female office worker who developed symptomatic hypocalcemia with severe vitamin D deficiency following treatment for Graves’ disease with methimazole. The patient’s hypocalcemia was mainly caused by vitamin D deficiency due to unbalanced diets and inadequate exposure to sunlight in addition to the resolution of hyperthyroidism. Vitamin D deficiency is increasing worldwide, and it has been more recently shown to relate to the pathogenesis of Graves’ disease. However, vitamin D deficiency as a cause of hypocalcemia has received little attention. Taken together, this case suggests that we should take more care in calcium kinetics and vitamin D status during treatment for Graves’ disease with antithyroid drugs.

YKL-40 is a marker of inflammation and endothelial dysfunction, both of which play important roles in the progression of diabetic complications. However, little information has been obtained about serum YKL-40 levels in type 1 diabetic patients. We evaluated YKL-40 levels and its association with diabetic micro- and macroandgiopathy in 131 young Japanese type 1 diabetic patients without advanced diabetic complications (aged 24.7±5.9 years) and 97 age- and gender-matched healthy controls. YKL-40 levels were significantly elevated in type 1 diabetic patients than in healthy controls (median (range) 46.4 (20.3-136.7) and 52.3 (21.4-274.1) ng/mL, respectively, p = 0.003). There was a significant positive association between YKL-40 levels and urinary albumin creatinine ratio (UACR) (r = 0.226, p = 0.013). Furthermore, a multivariate regression analysis demonstrated that YKL-40 levels were a determinant of UACR independently of conventional risk factors. In addition, YKL-40 levels were significantly higher in participants with diabetic retinopathy compared to those without it (median (range) 55.5 (23.3-274.1) and 50.3 (21.4-237.4) ng/mL, respectively, p = 0.039). Serum YKL-40 levels were elevated in type 1 diabetic patients and associated with increasing level of albuminuria. YKL-40 could be a predictor to assess the risk of diabetic microangiopathy in the early stage in type 1 diabetic patients.

To compare the diurnal glycemic profiles obtained with basal insulin degludec (InsDeg) and basal insulin glargine (InsGla) in patients with type 1 diabetes using continuous glucose monitoring (CGM) in an outpatient setting. Twenty Japanese patients with type 1 diabetes who were using once-daily InsGla before supper as part of their multiple daily insulin injections were consecutively recruited. CGM was initiated before supper on day 1, and InsGla was switched to InsDeg at the same dose on day 3. The average CGM glucose profile obtained on days 1 and 2 was compared with the corresponding profile for days 5 and 6. The bolus insulin regimen was not changed during the study period. CGM glucose was significantly higher (p

Background Experimental studies have suggested that dipeptidyl peptidase-4 (DPP-4) inhibitors provide cardiovascular protective effects. We performed a randomized study to evaluate the effects of sitagliptin added on to the conventional therapy compared with conventional therapy alone (diet, exercise, and/or drugs, except for incretin-related agents) on the intima-media thickness (IMT) of the carotid artery, a surrogate marker for the evaluation of atherosclerotic cardiovascular disease, in people with type 2 diabetes mellitus (T2DM). Methods and Findings We used a multicenter PROBE (prospective, randomized, open label, blinded endpoint) design. Individuals aged ≥30 y with T2DM (6.2% ≤ HbA1c < 9.4%) were randomly allocated to receive either sitagliptin (25 to 100 mg/d) or conventional therapy. Carotid ultrasound was performed at participating medical centers, and all parameters were measured in a core laboratory. Of the 463 enrolled participants with T2DM, 442 were included in the primary analysis (sitagliptin group, 222; conventional therapy group, 220). Estimated mean (± standard error) common carotid artery IMT at 24 mo of follow-up in the sitagliptin and conventional therapy groups was 0.827 ± 0.007 mm and 0.837 ± 0.007 mm, respectively, with a mean difference of −0.009 mm (97.2% CI −0.028 to 0.011, p = 0.309). HbA1c level at 24 mo was significantly lower with sitagliptin than with conventional therapy (6.56% ± 0.05% versus 6.72% ± 0.05%, p = 0.008; group mean difference −0.159, 95% CI −0.278 to −0.041). Episodes of serious hypoglycemia were recorded only in the conventional therapy group, and the rate of other adverse events was not different between the two groups. As it was not a placebo-controlled trial and carotid IMT was measured as a surrogate marker of atherosclerosis, there were some limitations of interpretation. Conclusions In the PROLOGUE study, there was no evidence that treatment with sitagliptin had an additional effect on the progression of carotid IMT in participants with T2DM beyond that achieved with conventional treatment. Trial Registration University Hospital Medical Information Network Clinical Trials Registry UMIN000004490, In a randomized controlled trial, Koichi Node and colleagues assess the efficacy of sitagliptin in limiting atherosclerosis among patients over 29 years of age living in Japan., Author Summary Why Was This Study Done? Translational research suggests that dipeptidyl peptidase-4 (DPP-4) inhibitors, which are drugs for type 2 diabetes mellitus (T2DM), may prevent cardiovascular disease to a greater extent than other T2DM drugs. However, recently published large clinical trials showed no additional efficacy for DPP-4 inhibitors beyond that expected for the drugs’ glycemic control. Possibly these studies showed no benefit to cardiovascular health because they assessed cardiovascular mortality and other relatively rare outcomes. Change in carotid intima-media thickness (IMT) is a simple, noninvasive method to assess atherosclerosis, an intermediate and more common condition that can precede cardiovascular disease. What Did the Researchers Do and Find? We conducted a trial to evaluate whether DPP-4 inhibitors affect atherosclerosis in people with T2DM. In all, 463 participants recruited at 48 medical centers were randomly divided into two groups and treated with sitagliptin, a DPP-4 inhibitor, or other conventional drugs for two years. Carotid IMT was evaluated with ultrasonography in a blinded manner. We found that annual changes in carotid IMT were not significantly different between the two groups. On the other hand, the decrease in HbA1c and in the incidence of hypoglycemia with sitagliptin were superior to conventional therapy. The rate of other adverse events was not different between the two groups. What Do These Findings Mean? These findings provide no evidence that sitagliptin slows the progression of carotid intima-media thickening in participants with T2DM to a greater extent than conventional drugs. As some of the conventional anti-T2DM drugs have shown anti-atherosclerotic effects in clinical trials, the present findings do not mean that sitagliptin does not possess anti-atherosclerotic properties in participants with T2DM. Importantly, however, sitagliptin is useful for controlling hyperglycemia for clinical setting.

The aim of the present study was to evaluate the usefulness of a closed-loop system (STG-55; Nikkiso, Tokyo, Japan), a type of artificial endocrine pancreas for the continuous monitoring and control of intraoperative blood glucose, for preventing postoperative acute kidney injury (AKI) in patients undergoing hepatectomy. Thirty-eight patients were enrolled in this study. Glucose concentrations were controlled with either a manual injection of insulin based on a commonly used sliding scale (manual insulin group, n = 19) or the programmed infusion of insulin determined by the control algorithm of the artificial endocrine pancreas (programmed insulin group, n = 19). After the induction of anesthesia, a 20-G intravenous catheter was inserted into the peripheral forearm vein of patients in the programmed insulin group and connected to an artificial endocrine pancreas (STG-55). The target range for glucose concentrations was set to 100–150 mg/dL. The mean serum creatinine concentrations of preoperative, postoperative 24 and 48 h were 0.72, 0.78, and 0.79 mg/dL in the programmed insulin group, and 0.81, 0.95, and 1.03 mg/dL in the manual insulin group, respectively. Elevations in serum creatinine concentrations postoperative 48 h were significantly suppressed in the programmed insulin group. The STG-55 closed-loop system was effective for maintaining strict blood glucose control during hepatectomy with minimal variability in blood glucose concentrations and for suppressing elevations in serum creatinine concentrations. Strict blood glucose control by an artificial endocrine pancreas during hepatectomy may prevent postoperative AKI.

Carboxy-terminal telopeptide of type I collagen (ICTP) is generated through matrix metalloproteinase (MMP)-dependent type I collagen digestion, and has been widely utilized as a biomarker for bone turnover. The fact that atherosclerotic lesions are rich in both type I collagen and MMP-producing macrophages led to the hypothesis that serum ICTP concentrations may serve as a non-invasive clinical biomarker for atherosclerosis. Therefore, the association of serum ICTP concentrations with the maximum intima-media thickness (IMT) of carotid arteries, a surrogate index of systemic atherosclerosis, or brachial-ankle pulse wave velocity (baPWV) in patients with atherosclerotic risk factors was evaluated. A total of 52 male and 65 female (mean age: 62.8 yrs) patients without renal failure, malignancies or bone diseases known to affect serum ICTP concentrations were recruited. Patients with max IMTs ≥1.1 mm showed significantly higher serum ICTP concentrations compared with patients with max IMTs

To evaluate the efficacy and safety of insulin glargine 300U/mL (Gla-300) versus glargine 100U/mL (Gla-100) in adults with type 1 diabetes in Japan over 12months.EDITION JP 1 was a multicentre, randomised, open-label phase 3 study. Following a 6-month on-treatment period, participants continued to receive Gla-300 or Gla-100 once daily, plus mealtime insulin, over a 6-month open-label extension phase. HbA1c, hypoglycaemia, body weight and adverse events were assessed.Overall, 114/122 (93%) and 114/121 (94%) of participants in the Gla-300 and Gla-100 group, respectively, completed the 6-month extension phase. Glycaemic control was sustained in both groups up to month 12 (mean HbA1c: Gla-300, 7.9% [62mmol/mol]; Gla-100, 7.8% [62mmol/mol]). Annualised rates of hypoglycaemia were lower with Gla-300 versus Gla-100; significantly for nocturnal confirmed (3.0mmol/L [54mg/dL]) or severe hypoglycaemia (2.39 and 3.85 events per participant-year; rate ratio: 0.62 [0.39-0.97]). No between-treatment differences in mean body weight change or adverse events were observed.Over 12months' treatment, participants with type 1 diabetes receiving Gla-300 achieved sustained glycaemic control and experienced less nocturnal hypoglycaemia that was confirmed (3.0mmol/L [54mg/dL]) or severe compared with Gla-100, supporting the 6-month results.

The effectiveness of diabetes prevention programs for the general population of Tokushima Prefecture was investigated. The programs were designed by Tokushima Medical Association’s (TMA’s) Steering Committee for Diabetes Prevention. The committee promoted diabetes prevention by disseminating educational messages on diabetes to the general public and medical care providers, and by establishing a referral system among public health centers and medical institutes throughout Tokushima Prefecture during the period from 2004 to 2009. The outcomes of these activities were evaluated by analyzing data from Prefectural Health and Nutrition Surveys conducted in Tokushima in 1997 (n = 998), 2003 (n = 1,008) and 2010 (n = 1,130). The percentage of subjects with glucose intolerance at the time of initiation of the prevention program in Tokushima tended to increase from 1997 to 2003, but had slightly decreased by 2010, although these differences were not statistically significant. Obesity parameters, mean total energy intake and physical activity as evaluated by the daily step count changed favorably in parallel with changes in the prevalence of diabetes during the study period. The diabetes prevention programs initiated by the TMA committee may be useful in ameliorating the situation of diabetes in Tokushima Prefecture.

The aim of the present study was to compare the usefulness of premeal rapid‐acting and regular insulin in type 2 diabetes patients. A total of 56 type 2 diabetic patients were investigated during hospitalization. Premeal rapid‐acting insulin was applied instead of other medications. Premeal insulin was titrated to adjust premeal and bedtime blood glucose levels to 81–120 mg/dL. Premeal rapid‐acting insulin was changed to regular insulin just before a meal at the same dosage if the postmeal blood glucose level was lower than the premeal blood glucose level. A total of 15 patients changed to regular insulin, and 41 patients continued rapid‐acting insulin. The blood glucose level was comparable between these two groups. Body mass index was significantly lower in the patients using regular insulin. According to the multivariate logistic regression analysis, low body mass index was an independent variable accounting for the usefulness of regular insulin. Regular insulin, rather than rapid‐acting insulin, is a suitable choice for premeal insulin in lean type 2 diabetic patients.

Objective Adiponectin has anti-atherogenic properties and reduced serum adiponectin levels are associated with cardiovascular disease (CVD). In this study, we examined the relationship between CVD and adiponectin ( ADIPOQ ) gene G276T polymorphism that is associated with serum adiponectin level in a large cohort of type 2 diabetic patients. Research design and methods We enrolled 2637 Japanese type 2 diabetic subjects (males, 61.1%; age, 54.9±7.9 years old), determined their genotypes regarding ADIPOQ G276T polymorphisms, and evaluated the association between this polymorphism and the prevalence of CVD (myocardial infarction and/or cerebral infarction). Results The prevalence of CVD tended to be higher as the number of G alleles increased [GG (9.5%), GT (6.8%), TT (5.6%), p value for trend=0.0059] and was significantly higher in the subjects with GG genotype compared to those with GT or TT genotype (9.5% vs. 6.6%, p =0.0060). Multiple logistic regression analyses revealed that the number of G alleles (Odds ratio (OR)=1.49 with 95%CI 1.09–2.05, p =0.0125) and GG genotype (OR=1.66 with 95%CI 1.13–2.43, p =0.0098) were significantly associated with CVD even after adjustment for conventional risk factors. Interestingly, the presence of obesity further and significantly increased the risk of CVD in the subjects with GG genotype (OR=1.67 with 95%CI 1.14–2.44, p =0.0090) but not in the subjects with TT or GT genotype (OR=1.17 with 95%CI 0.73–1.89, NS). Conclusions It is likely that the G allele of the ADIPOQ G276T polymorphism is a susceptibility allele for CVD in Japanese type 2 diabetic patients, especially when they accompany obesity.

It is likely that the C allele of the polymorphism at position −106 in the promoter of aldose reductase gene, which codes a rate-limiting enzyme of the polyol pathway, is a susceptibility allele for diabetic retinopathy in Japanese type 2 diabetic patients.

fujiwara y., kishida k., terao m., takahara m., matsuhisa m., funahashi t., shimomura i. & shimizu y. (2011) Beneficial effects of foot care nursing for people with diabetes mellitus: an uncontrolled before and after intervention study. Journal of Advanced Nursing 67(9), 1952–1962. Abstract Aim. The aim of this study was to assess the effectiveness of a preventative foot care nursing programme for diabetic patients. Background. Foot complications are common in diabetic patients and prevention of such complications requires foot care. However, there is little information on the effectiveness of foot care nursing on the incidence and recurrence of diabetic foot. Methods. We developed a diabetic foot care programme based on the International Working Group on the Diabetic Foot. We studied 88 patients who attended our foot care programme for 2 years, and collected data from April 2005 to March 2009. Patients were divided into four groups according to the risk classification, and received foot care. We evaluated the incidence of foot ulceration or recurrence and non-ulcerated foot condition. Characteristics of the patients were analysed using the paired t-test and McNemar’s test, and changes in severity of tinea pedis and grade of callus were analysed using Wilcoxon’s signed rank sum test. Results. The programme reduced the severity score of tinea pedis (P

It is indicated that total/HDL cholesterol and LDL/HDL cholesterol ratios have more predictive power for cardiovascular disease compared to classic lipid parameters. However, there have been few reports about the usefulness of these indices for the assessment of early stage atherosclerosis in Japanese type 2 diabetic subjects.We examined the relation between various lipid parameters and carotid atherosclerosis in 934 type 2 diabetic subjects without apparent atherosclerotic diseases (males, 71.7%; age, 59.6 ± 10.5 years (mean ± SD)). Serum concentrations of total cholesterol (TC), HDL cholesterol (HDL-C), and triglyceride were measured. LDL cholesterol (LDL-C) level was calculated using the Friedewald formula. The presence of carotid plaque and intima-media thickness (IMT) were evaluated by ultrasonography.A stepwise multivariate regression analysis demonstrated that HDL-C (β = -0.110, p0.001), TC/HDL-C (β = 0.132, p0.001) and LDL-C/HDL-C ratios (β = 0.132, p0.001) were independent determinants of IMT even after adjustment of other conventional risk factors. However, there was no significant correlation between IMT and TC, triglyceride, LDL-C, and non-HDL-C levels. TC/HDL-C and LDL-C/HDL-C ratios and non-HDL-C levels were significantly higher, but HDL-C levels were significantly lower in patients with carotid plaque than those without it (p0.05). There was no significant difference between the groups regarding TC, LDL-C, and triglyceride levels. Furthermore, TC/HDL-C (OR; 1.34, p0.001) and LDL-C/HDL-C (OR; 1.54, p0.001) ratios showed a positive and linear relationship with the prevalence of carotid plaque, whether covariates were adjusted or not.TC/HDL-C and LDL-C/HDL-C ratios are useful as a tool to assess the risk of early stage atherosclerosis in Japanese type 2 diabetic patients.

Objective: Progressive β-cell dysfunction and loss of β-cell mass are fundamental pathogenic features of type 2 diabetes. To examine if anti-diabetic reagents, such as insulin, pioglitazone (pio), and alogliptin (alo), have protective effects on β-cell mass and function in vivo, we treated obese diabetic db/db mice with these reagents. Methods: Male db/db mice were treated with a chow including pio, alo, or both of them from 8 to 16 weeks of age. Insulin glargine (gla) was daily injected subcutaneously during the same period. Results: At 16 weeks of age, untreated db/db mice revealed marked increase of HbA1c level, whereas those treated with pio, pio + alo, or insulin revealed the almost same HbA1c levels as non-diabetic db/m mice. Islet mass evaluated by direct counting in the whole pancreas and insulin content in isolated islets were preserved in pio, pio + alo and gla groups compared with untreated or alo groups, and there was no difference among pio, pio + alo and gla groups. To precisely evaluate islet β-cell functions, islet perifusion analysis was performed. In pio, pio + alo and gla groups, biphasic insulin secretion was preserved compared with untreated or alo groups. In particular, pio + alo as well as gla therapy preserved almost normal insulin secretion, although pio therapy improved partially. To examine the mechanism how these reagents exerted beneficial effects on β-cells, we evaluated expression levels of various factors which are potentially important for β-cell functions by real-time RT-PCR and immunohistochemistry. The results showed that expression levels of MafA and GLP-1 receptor were markedly decreased in untreated and alo groups, but not in pio, pio + alo and gla groups. Conclusion: Combination therapy with pio and alo almost completely normalized β-cell functions in vivo, which was comparable with gla treatment.

膵移植は1型糖尿病において長期のインスリン離脱が期待できる唯一の根治治療である．本邦の膵移植後生存率や膵グラフト生着率は欧米に匹敵する優れた成績であるが，移植後インスリン離脱に時間を要する遷延性膵グラフト機能を呈する場合が多い．この理由として，高齢で死戦期に複数の昇圧剤を用いるマージナルドナーである場合が多いこと，また移植後急性期は免疫抑制薬を高用量必要とすることが挙げられる．そこで，インスリン離脱やグラフト障害を予知するため，移植後早期から膵グラフト機能の正確な評価が必要となる．筆者らは膵移植後72時間に人工膵島を用いた厳格な血糖管理を実施し，その時の必要インスリン量が1年の経過において，膵グラフト機能を反映する指標であることを見出している．これからの膵グラフト機能の長期安定化に向けて，β 細胞保護療法の確立が望まれるが，現状では移植後チーム医療による生活習慣への積極的介入が有効と考えられる．

The aim of this study was to examine the possible association of vitamin D deficiency with diabetic retinopathy in 75 young Japanese type 1 diabetic patients. A multivariate regression analysis, duration of diabetes and vitamin D deficiency were independent determinants of diabetic retinopathy.

We examined the association between diabetic retinopathy and monocyte chemoattractant protein (MCP)-1 A-2518G polymorphism in 3802 Japanese type 2 diabetic subjects. The prevalence of diabetic retinopathy was higher as the number of G alleles increased, suggesting that the G allele of this polymorphism is a susceptibility allele for diabetic retinopathy.

AIM Pioglitazone, an agonist of peroxisome proliferator-activated receptor gamma, showed various anti-atherosclerotic effects on type 2 diabetic patients. This retrospective study was done to ascertain which risk factor(s) associate with anti-atherosclerotic effects of pioglitazone. METHODS We enrolled 160 diabetic patients treated through diet only and 62 treated with pioglitazone and annually evaluated carotid maximum (MaxIMT) and averaged intima-media thickness (AveIMT) for 2 years. We analyzed the relation of 99 single-nucleotide polymorphisms (SNP) as well as conventional risk factors with the progression or regression of carotid atherosclerosis. RESULTS The D allele of the angiotensin-converting enzyme (ACE) gene and 677 allele of the methylene-tetrahydrofolate reductase (MTHFR) gene showed a significant association with increases in MaxIMT among the diabetic subjects treated through diet only. The pioglitazone-treated carriers of the D allele showed an attenuation of MaxIMT as compared with the diet-treated carriers. The pioglitazone-treated carriers of the 677T allele carriers showed a significant attenuation of MaxIMT compared with the diet-treated carriers. CONCLUSIONS Pioglitazone may exert anti-atherosclerotic effects on type 2 diabetics carrying the ACE gene's D allele and/or MTHFR gene's 677T allele, who showed a progression of carotid atherosclerosis without the drug.

OBJECTIVE It is believed that disruption of vulnerable atherosclerotic plaque and subsequent thrombus formation play critical roles in the pathogenesis of cerebral infarction. We simultaneously determined four relatively common genetic variants related to plaque rupture or subsequent local thrombus formation and evaluated the combined effect on cerebral infarction. RESEARCH DESIGN AND METHODS We enrolled 3,094 Japanese type 2 diabetic subjects (62.7% male; aged 61.5 ± 8.4 years) and determined their genotypes regarding matrix metalloproteinase 9 C-1562T, coagulation factor XII (F12) C46T, von Willebrand factor (VWF) G-1051A, and plasminogen activator inhibitor (PAI-1) 675 4G/5G polymorphisms. The diagnosis of cerebral infarction was performed based on history, physical examination, and neuroimaging. RESULTS The single association analysis revealed that there were no statistically significant associations between each polymorphism and the prevalence of cerebral infarction. Interestingly, the prevalence of cerebral infarction was higher with the increase of the total number of four concomitant unfavorable proatherothrombotic alleles in each subject (P value for linear trend = 0.004). Furthermore, a multiple logistic regression analysis showed that the number of proatherothrombotic alleles was a risk factor for cerebral infarction independently of conventional risk factors (odds ratio for one-point increase in the number of proatherothrombotic allele 1.15 [95% CI 1.05–1.26], P = 0.004). CONCLUSIONS Accumulation of gene polymorphisms related to plaque rupture and thrombus formation is likely associated with the prevalence of cerebral infarction in type 2 diabetic patients, suggesting that the combined information about these variants is useful to assess the risk of cerebral infarction.

A decrease in the number of functioning pancreatic beta-cells and insufficient insulin biosynthesis and/or secretion are the hallmarks of diabetes. Therefore, the identification of alternative sources to induce insulin-producing surrogate beta-cells is of great importance. For the induction of insulin-producing cells from various cells and/or tissues, it is useful to mimic and reproduce expression alterations of various pancreatic transcription factors observed during normal pancreas development and to induce key pancreatic transcription factors which have the potency to induce insulin and other beta-cell-related genes. MafA, PDX-1 and NeuroD directly bind to the insulin gene promoter and function as very important transcription factors in pancreatic beta-cell differentiation and mature beta-cell function. The combination of MafA, PDX-1 and NeuroD markedly induces insulin biosynthesis in various non-beta-cells and thereby is a useful tool to efficiently induce insulin-producing surrogate beta-cells.

Objective Advanced glycation end-products (AGEs) and the receptor for AGEs (RAGE) system plays an important role in the development of atherosclerosis. It has been recently reported that endogenous secretory RAGE (esRAGE) and total soluble RAGE (sRAGE) levels are associated with diabetic complications. The aim of the present study is to longitudinally evaluate the association between esRAGE and sRAGE levels and the progression of carotid intima-media thickness (IMT), a surrogate marker of atherosclerosis. Methods and results Japanese type 1 diabetic patients ( n =47, aged 24.0±3.1 years) were enrolled into a 4-year follow-up study and annual measurements of serum esRAGE and sRAGE levels and IMTs were performed. At baseline, mean-IMT was inversely correlated with circulating esRAGE levels ( r =−0.317, p =0.0292), whereas there was not statistical significance between mean-IMT and sRAGE levels. Mean-IMT significantly increased during the follow-up period (from 0.63±0.10 to 0.67±0.10mm, p =0.0022). Annual increase in mean-IMT (=(mean-IMT after 4 years−mean-IMT at baseline)/4) was positively correlated with the arithmetic average of systolic blood pressure ( r =0.310, p =0.0332) and triglyceride ( r =0.337, p =0.0201), and inversely correlated with circulating esRAGE levels ( r =−0.360, p =0.0124) and sRAGE levels ( r =−0.406, p =0.0042) during the follow-up period. Furthermore, stepwise multivariate regression analyses revealed that continuous low levels of circulating esRAGE and sRAGE were determinants of the progression of mean-IMT independently of conventional risk factors. Conclusions Circulating esRAGE level as well as sRAGE level was an independent risk factor for the progression of carotid IMT in type 1 diabetic subjects.

It is well known that oxidative stress plays critical roles in the pathogenesis of atherosclerosis. In this study, we enrolled 1746 type 2 diabetic subjects, determined 4 common genetic variants related to oxidative stress (glutamate-cysteine ligase modifier subunit (GCLM) C-588T, myeloperoxidase G-463A, human paraoxonase 1 Gln192Arg and NAD(P)H oxidase p22phox C242T polymorphisms), and measured carotid intima-media thickness (IMT) as a surrogate marker for atherosclerosis. GCLM C-588T polymorphism was associated with average IMT (AveIMT) (r=0.090, p=0.0008), but the association between the other 3 polymorphisms and AveIMT did not reach the statistical significance. However, AveIMT was significantly greater as the total number of 4 concomitant "pro-oxidant alleles" in each subject was increased (r=0.108, p0.0001). Furthermore, the number of "pro-oxidant alleles" was a risk factor for a high AveIMT independently of conventional risk factors (p=0.0003). In conclusion, accumulation of oxidative stress-associated alleles was associated with carotid atherosclerosis in type 2 diabetic patients.

To identify the location of pancreatic endocrine tumors, arterial stimulation and venous sampling (ASVS) is known to be useful for insulinoma and gastrinoma, but its usefulness for glucagonoma has not been verified to date. Here we report a case of glucagonoma that was diagnosed by ASVS with calcium loading, in which an approximately 6-fold increase of glucagon was observed in the splenic artery territory. MEN1 gene analysis verified the presence of a mutation and the glucagonoma was confirmed after operation. In conclusion, ASVS could be useful for the diagnosis of glucagonoma.

It is known that endoplasmic reticulum (ER) stress is provoked under diabetic conditions and is possibly involved in the development of insulin resistance. In this study, using ER stress-activated indicator (ERAI) transgenic mice which express green fluorescent protein under ER stress conditions, we directly evaluated the effects of a diabetic agent pioglitazone on in vivo ER stress under diabetic conditions. In high fat and high sucrose diet-induced diabetic ERAI transgenic mice, 8 weeks of pioglitazone treatment reduced the accumulation of fat droplets in the liver and attenuated the development of insulin resistance. In the liver of the ERAI transgenic mice, ERAI fluorescence activity was clearly reduced as early as after 4 weeks of pioglitazone treatment, preceding the improvement of insulin resistance. In addition, after the pioglitazone treatment, serum free fatty acid and triglyceride levels were decreased, and serum adiponectin levels were increased. These data indicate that pioglitazone treatment suppresses ER stress in the liver which may explain, at least in part, the pharmacological effects of pioglitazone to reduce insulin resistance.

Integrated backscatter (IBS) signal obtained by extracranial ultrasound examination of the carotid artery can be used to evaluate the tissue characteristics of arterial plaque. To examine whether clustering of several cardiovascular risk factors, metabolic syndrome (MetS), affects the tissue characteristics of the carotid artery, we measured Calibrated-IBS values of the intima–media complex in the carotid artery for 142 patients (61.6±9.5 years old) with at least one component of MetS. Calibrated-IBS values were inversely correlated with the number of MetS components ( r =−0.224, p =0.0073). Furthermore, the number of MetS components was an independent risk factor for a low Calibrated-IBS. The subjects with coronary heart disease (CHD) ( n =20) showed significantly lower Calibrated-IBS than those without it ( n =122) (−17.8±5.1 vs. −21.7±5.5dB, p =0.0020), and the logistic regression analysis showed that the presence of CHD was associated with Calibrated-IBS (RR=0.898, 95%CI: 0.811–0.994, p =0.0374). These results suggest that clustering of the cardiovascular risk factors affects the Calibrated-IBS, an acoustic parameter of tissue characteristics of the intima–media complex in the carotid artery.

To clarify factors determining the preference for a self-monitoring blood glucose (SMBG) system in patients with diabetes mellitus. A total of 52 Japanese inpatients with diabetes mellitus were recruited into a single-center trial. After the patients got used to one SMBG system, the SMBG system was substituted with another one of the three, and the subjects were given questionnaires. The following parameters were identified as independent factors associated with the preference of SMBG: display (P0.0001), operation for inserting strips (P=0.0004), and lancing-device operation (P0.05). When the subjects were divided according to age, the independent variables associated with overall preference in the older group (or=60 years) were display (P=0.001) and procedure for detaching a used needle (P=0.01), whereas those in the younger group (age60 years) were operation of the lancing device (P0.0001), operation to apply blood to strip (P=0.001), and amount of blood (P=0.04). These data suggest that in elderly patients with diabetes, display and detachment of the needle are important factors affecting the choice of SMBG system, whereas younger subjects give weight to skin puncture-related issues in choosing an SMBG system.

New-onset diabetes after renal transplantation (NODAT) is known to be a potent risk factor for cardiovascular events. We therefore investigated the incidence and risk factors for NODAT, and evaluated surrogate endpoints of atherosclerosis in Japanese patients with stable renal function after renal transplantation. Seventy-nine patients were enrolled in the study, and a 75 g oral glucose tolerance test (OGTT) was performed in subjects excluding patients with known NODAT. We evaluated the risk factors for NODAT and the degree of atherosclerosis, determined by brachial-ankle pulse wave velocity (baPWV), ankle-brachial blood pressure index (ABPI) and intima-media thickness (IMT) of the carotid artery. Eleven patients diagnosed as NODAT had significantly higher fasting plasma glucose before transplantation, blood pressure, and incidence of hepatitis C virus (HCV) infection than patients without NODAT. Multivariate regression analysis revealed that the independent determinant of NODAT was fasting plasma glucose pre-transplantation, HCV infection and systolic blood pressure. The baPWV in patients with NODAT was significantly higher compared to that in patients without NODAT. In addition, the independent determinant of baPWV evaluated by multivariate regression analysis was an increase in systolic blood pressure and age, and a decrease of adiponectin levels. In conclusion, we found that high fasting plasma glucose prior to transplantation, HCV infection and high blood pressure are risk factors for NODAT in Japanese patients after renal transplantation. Since NODAT patients have advanced arterial stiffness probably due to high blood pressure, strict control of blood pressure will be important for preventing the development of cardiovascular disease in NODAT.

Insulin transcription factor MafA is unique in being exclusively expressed at the secondary and principal phase of insulin-expressing cell production during pancreas organogenesis and is the only transcriptional activator present exclusively in islet β-cells. Here we show that ectopic expression of MafA is sufficient to induce a small amount of endogenous insulin expression in a variety of non-β-cell lines. Insulin mRNA and protein expression was induced to a much higher level when MafA was provided with two other key insulin activators, pancreatic and duodenal homeobox (PDX-1) and BETA2. Potentiation by PDX-1 and BETA2 was entirely dependent upon MafA, and MafA binding to the insulin enhancer region was increased by PDX-1 and BETA2. Treatment with activin A and hepatocyte growth factor induced even larger amounts of insulin in AR42J pancreatic acinar cells, compared with other non-β endodermal cells. The combination of PDX-1, BETA2, and MafA also induced the expression of other important regulators of islet β-cell activity. These results support a critical role of MafA in islet β-cell function.

Insulin resistance is the principal cause of glucose intolerance and type 2 diabetes and induces progression of severe atherosclerosis in these patients. Adiponectin, the adipose-specific proteins, is known to correlate negatively with insulin resistance in patients with obesity and type 2 diabetes. The purpose of this study was to evaluate the potential of using serum adiponectin levels as a marker of insulin resistance in various states of insulin resistance. Furthermore, we attempted to establish a modified index of the homeostasis model assessment index (HOMA-IR), calculated from the product of serum insulin and plasma glucose levels divided by serum adiponectin levels (HOMA-AD). We recruited 117 Japanese subjects with various degrees of glucose tolerance and determined serum adiponectin levels and insulin sensitivity (M-value) by using the euglycemic hyperinsulinemic clamp technique. M-value, the gold standard index of insulin resistance, correlates significantly and independently with fasting insulin (r=-0.313, P0.001), glucose (r=-0.319, P0.001), and adiponectin (r=0.241, P0.002) levels. M-values were more significantly correlated with HOMA-AD (r=-0.643, P0.001) than HOMA-IR values (r=-0.591, P0.001). In subjects with moderate hyperglycemia (fasting glucose levels8.0mmol/L, n=30), HOMA-AD showed a more significant correlation with the M-value than HOMA-IR (r=-0.535, P=0.005 versus r=-0.461, P=0.010). We would therefore like to propose a novel index, HOMA-AD, as a simple and adequate index for determining insulin resistance even in diabetic patients with overt hyperglycemia.

Advanced glycation end-products (AGEs) are thought to play a major role in the pathogenesis of diabetic vascular complications. Skin autofluorescence (AF) was recently reported to represent tissue AGEs accumulation with a non-invasive method. The aim of the present study was to evaluate association between AF value and diabetic vascular complications, such as retinopathy, nephropathy and cervical atherosclerosis using the carotid intima-media thickness (IMT), an established marker of cardiovascular disease in patients with type 2 diabetes. A total of 68 patients with type 2 diabetes were enrolled in a cross-sectional manner. AGEs accumulation was measured with AF reader. Clinical parameters were collected at the time of AF and IMT measurement. Max-IMT was correlated with age and AF (r=0.407, p=0.001), but not with HbA1c, GA, and pentosidine. Also, AF was not correlated with HbA1c, GA and pentosidine, but was correlated with age (r=0.560, p

Several guidelines have recently recommended exercise for prevention and treatment of type 2 diabetes. However, determining the optimum exercise conditions, e.g., the intensity, amount, frequency, and type of exercise, is difficult, particularly by patients themselves. We have investigated the acute effect of fast walking on postprandial blood glucose levels among patients with type 2 diabetes.Fourteen patients diagnosed with type 2 diabetes at least 1 year previously were eligible for inclusion in this study during educational hospitalization. Three walking programs, natural walking (walking at a natural speed), 10 % fast walking, and 20 % fast walking, were performed 1 h after lunch in a randomized sequence with a washout period of 1 day. Walking time was 30 min in all the programs. Primary outcome was determined by self-monitoring of blood glucose. Blood glucose levels were measured before walking, after walking for 15 min, and at the end of walking. Heart rate and systolic and diastolic pressure were also measured for safety reasons.All the participants completed the study with no adverse effects. Compared with natural walking, fast walking markedly improved postprandial glucose excursion in an intensity-dependent manner without any adverse effects.Fast walking acutely reduced postprandial blood glucose levels among patients with type 2 diabetes. Our method has major implications for the practice of diabetes education in clinical rehabilitation.

Nateglinide, a rapid insulin secretagogue, is known to facilitate the early phase of insulin secretion and has been used for the treatment of type 2 diabetic patients with postprandial hyperglycemia. The aim of this study is to evaluate the effect of nateglinide on insulin resistance as well as insulin secretory defects in type 2 diabetic patients. Insulin secretion ability was evaluated by the hyperglycemic clamp test, and insulin sensitivity was evaluated by the euglycemic hyperinsulinemic clamp test, using an artificial pancreas. The hyperglycemic clamp test showed that a 7-day treatment with nateglinide significantly increased insulin secretion in response to high glucose. Interestingly, although nateglinide is known to facilitate insulin secretion, daily urinary C-peptide excretion was decreased after nateglinide treatment. Moreover, in the euglycemic hyperinsulinemic clamp test, glucose infusion rate was significantly increased by nateglinide treatment, indicating that nateglinide functions to decrease insulin resistance. Nateglinide ameliorates insulin resistance as well as insulin secretory defects in type 2 diabetic patients.

It has been shown that oxidative stress and activation of the c-Jun N-terminal kinase (JNK) pathway induce the nucleocytoplasmic translocation of the pancreatic transcription factor PDX-1, which leads to pancreatic beta-cell dysfunction. In this study, we have shown that the forkhead transcription factor Foxo1/FKHR plays a role as a mediator between the JNK pathway and PDX-1. Under oxidative stress conditions, Foxo1 changed its intracellular localization from the cytoplasm to the nucleus in the pancreatic beta-cell line HIT-T15. The overexpression of JNK also induced the nuclear localization of Foxo1, but in contrast, suppression of JNK reduced the oxidative stress-induced nuclear localization of Foxo1, suggesting the involvement of the JNK pathway in Foxo1 translocation. In addition, oxidative stress or activation of the JNK pathway decreased the activity of Akt in HIT cells, leading to the decreased phosphorylation of Foxo1 following nuclear localization. Furthermore, adenovirus-mediated Foxo1 overexpression reduced the nuclear expression of PDX-1, whereas repression of Foxo1 by Foxo1-specific small interfering RNA retained the nuclear expression of PDX-1 under oxidative stress conditions. Taken together, Foxo1 is involved in the nucleocytoplasmic translocation of PDX-1 by oxidative stress and the JNK pathway.

OBJECTIVE—The binding of advanced glycation end products (AGEs) to their receptor (RAGE) plays an important role in the development of diabetic vascular complications. In the present study, we examined circulating endogenous secretory RAGE (esRAGE) levels in subjects with type 1 diabetes and explored the possible association between esRAGE levels and the severity of diabetic vascular complications. RESEARCH DESIGN AND METHODS—Circulating esRAGE levels in serum were examined in 67 Japanese type 1 diabetic patients (22 men and 45 women, age 24.0 ± 4.4 years [means ± SD]) and 23 age-matched healthy nondiabetic subjects (10 men and 13 women aged 24.9 ± 1.4 years). Daily urinary albumin excretion, the presence of retinopathy, and intima-media thickness (IMT) of the carotid artery were also evaluated. We further explored the association between esRAGE levels and severity of diabetic vascular complications. RESULTS—Circulating esRAGE levels were significantly lower in subjects with type 1 diabetes than in nondiabetic subjects (0.266 ± 0.089 vs. 0.436 ± 0.121 ng/ml, respectively, P < 0.0001) and was inversely correlated with HbA1c (A1C) levels (r = −0.614, P < 0.0001). In addition, multivariate regression analysis demonstrated that A1C was an independent risk factor for a low esRAGE value. Furthermore, circulating esRAGE levels were inversely correlated with carotid IMT (r = −0.325, P = 0.0017) and was one of the independent risk factors for IMT thickening. Furthermore, there was a significant difference (P = 0.0124) in esRAGE levels between patients without retinopathy (0.286 ± 0.092 ng/ml) and those with retinopathy (0.230 ± 0.074 ng/ml). CONCLUSIONS—Circulating esRAGE levels were significantly lower in type 1 diabetic patients than in nondiabetic subjects and were inversely associated with the severity of some diabetic vascular complications.

Peripheral vascular disease (PVD) has been reported to cause deterioration in insulin sensitivity. The precise mechanism of insulin resistance induced by PVD has not been clarified. To elucidate the mechanism causing impaired insulin action and glucose metabolism under peripheral ischemic conditions, we determined glucose turnover and glucose tolerance in hindlimb-ischemic (FAL) rats. The right femoral artery was ligated in hindlimb-ischemic (FAL) rats, while the artery was only exposed in the Sham operated (Sham) rats used as a control. Two weeks after the ligation, glucose tolerance was impaired and plasma insulin levels were significantly increased in FAL rats compared with Sham rats after intraperitoneal glucose loading (2 g kg(-1)). Under euglycemic hyperinsulinemic clamp conditions, the glucose infusion rate was significantly lower in FAL rats compared with Sham rats, but there was no significant difference in the glucose disappearance rate between the two groups. Hyperinsulinemia suppressed endogenous glucose production by 50% in Sham rats, while the suppression was 20% in FAL rats, indicating hepatic insulin resistance in FAL rats. mRNA analysis of isolated liver after the clamp experiment revealed that glucokinase mRNA, but not PEPCK and glucose-6-phosphatase mRNA, was significantly lower in FAL rats compared with Sham rats. In conclusion, chronic hindlimb ischemia impaired glucose tolerance associated with insulin resistance in the liver rather than the peripheral tissues.

Insulin resistance as well as pancreatic β-cell dysfunction is observed in type 2 diabetes. Recently, it has been shown that increase of endoplasmic reticulum (ER) stress and activation of the c-Jun N-terminal kinase (JNK) pathway are involved in the progression of insulin resistance found in diabetes. Indeed, suppression of ER stress or the JNK pathway in diabetic mice improves insulin resistance and ameliorates glucose tolerance. Thus, increase of ER stress and activation of the JNK pathway play a central role in pathogenesis of type 2 diabetes and could be a potential target for diabetes therapy.

Diabetes is the most prevalent and serious metabolic disease, and the number of diabetic patients worldwide is increasing. The reduction of insulin biosynthesis in pancreatic β-cells is closely associated with the onset and progression of diabetes, and thus it is important to search for ways to induce insulin-producing cells in non−β-cells. In this study, we showed that a modified form of the pancreatic and duodenal homeobox factor 1 (PDX-1) carrying the VP16 transcriptional activation domain (PDX-1/VP16) markedly increases insulin biosynthesis and induces various pancreas-related factors in the liver, especially in the presence of NeuroD or neurogenin 3 (Ngn3). Furthermore, in streptozotocin-induced diabetic mice, PDX-1/VP16 overexpression, together with NeuroD or Ngn3, drastically ameliorated glucose tolerance. Thus PDX-1/VP16 expression, together with NeuroD or Ngn3, markedly induces insulin gene transcription and ameliorates glucose tolerance. This approach warrants further investigation and may have utility in the treatment of diabetes.

Pancreatic beta-cell dysfunction and insulin resistance are observed in type 2 diabetes. Under diabetic conditions, oxidative stress and ER stress are induced in various tissues, leading to activation of the JNK pathway. This JNK activation suppresses insulin biosynthesis and interferes with insulin action. Indeed, suppression of the JNK pathway in diabetic mice improves insulin resistance and ameliorates glucose tolerance. Thus, the JNK pathway plays a central role in pathogenesis of type 2 diabetes and may be a potential target for diabetes therapy.

An open randomized prospective study was performed to elucidate the effect of an alpha-glucosidase inhibitor, voglibose, on the progression of atherosclerosis in subjects with type 2 diabetes.Voglibose at a dose of 0.4-0.6 mg/day was added on 51 subjects out of 101 type 2 diabetic patients being treated with diet, sulphonylurea (SU) or insulin injections, and the average (AveIMT) and maximum intima-media thickness (MaxIMT) of their carotid arteries were examined for 3 years.Irrespective of the differences in treatments, addition of voglibose reduced the progression of AveIMT and MaxIMT to -0.024 +/- 0.047 (+/-S.D.) and -0.021 +/- 0.144 mm/year, respectively. Without voglibose, diabetic patients showed significant (P0.0001) progression of AveIMT and MaxIMT (0.056 +/- 0.046 and 0.098 +/- 0.122 mm/year, respectively). The administration of voglibose resulted in a significant reduction of hemoglobin A1c (HbA1c), total cholesterol and triglyceride concentrations, as well as an increase in HDL cholesterol concentration. Multivariate regression analysis showed that administration of voglibose independently reduced the progression of AveIMT by 0.069 mm/year (P0.0001).These results suggest that voglibose reduces the progression of IMT and may be a candidate for an anti-atherosclerotic drug for type 2 diabetic patients.

Under diabetic conditions, oxidative stress is induced and the JNK pathway is activated, which is involved in deterioration of pancreatic beta-cell function found in diabetes. Oxidative stress and/or activation of the JNK pathway suppress insulin gene expression, accompanied by reduction of PDX-1 DNA binding activity. Treatment with antioxidants and/or suppression of the JNK pathway protect beta-cells from some of the toxic effects of hyperglycemia. The JNK pathway is also involved in the progression of insulin resistance; suppression of the JNK pathway in obese diabetic mice markedly improves insulin resistance and ameliorates glucose tolerance. The phosphorylation state of key molecules for insulin signaling is altered upon modification of the JNK pathway. Taken together, the JNK pathway plays a crucial role in progression of insulin resistance as well as beta-cell dysfunction found in diabetes and thus could be a potential therapeutic target for diabetes.

The proliferation of vascular smooth muscle cells (VSMCs) and alterations of their phenotype are implicated in the pathogenesis of atherosclerosis. Arterial wall injury induces the expression of proto-oncogenes, leading to the proliferation of VSMCs. In particular, c-Myc and c-Myb play a central role in cell cycle progression and are essential for VSMC replication. The protooncogene Pim-1 cooperates with c-Myc and enhances the transcriptional activity of c-Myb in hematopoietic cells, suggesting that Pim-1 is involved in cell cycle regulation. The aim of this study was to examine the possible involvement of Pim-1 in VSMC proliferation. Pim-1 was substantially induced in neointimal VSMCs of balloon-injured rat carotid arteries, and in vivo infection with a dominant negative Pim-1-expressing adenovirus (Ad-DN-Pim-1) markedly suppressed neointima formation and cell cycle progression in the balloon-injured arteries. In cultured VSMCs, treatment with serum or H(2)O(2) induced Pim-1 expression, and H(2)O(2)- or serum-stimulated cell cycle progression and DNA synthesis were almost completely inhibited by DN-Pim-1 overexpression. Furthermore, we performed immunohisto-chemical staining for Pim-1 in human thoracic aortas and coronary arteries obtained from six individuals at autopsy and found that Pim-1-positive cells are observed predominantly in the thickened intima of the aortas and coronary arteries. To the best of our knowledge, this is the first report showing Pim-1 expression in rodent and human arterial walls. To summarize, Pim-1 expression was observed in the neointima of balloon-injured rat carotid arteries and in human thoracic aortas and coronary arteries showing intimal thickening, and the specific inhibition of Pim-1 function markedly suppressed neointima formation after balloon injury and the proliferation of cultured VSMCs, suggesting that Pim-1 plays a role in VSMC proliferation.

Metformin is a well-known oral hypoglycaemic agent and has been commonly used, in combination with sulphonylurea, to treat type 2 diabetes. However, the advantageous effect of metformin plus sulphonylurea on diabetic macroangiopathy has yet to be clarified. To evaluate whether sulphonylurea or sulphonylurea plus metformin prevent diabetic macroangiopathy, we examined the progression of carotid artery intima-media thickness (IMT) as a surrogate end point.Subjects with type 2 diabetes were divided into three groups, receiving the following treatments: (i) glibenclamide (n=59); (ii) gliclazide (n=30); and (iii) glibenclamide + metformin (n=29). Maximum IMT and average IMT (the greatest value among 6 average values of each 3 points including greatest thickness) were measured at the beginning and end of the observation period.For the follow-up period of 3 years, the annual change in average IMT of the glibenclamide plus metformin group (0.003+/-0.048 mm) was smaller than that of the glibenclamide group (0.064+/-0.045 mm) and gliclazide group (0.032+/-0.036 mm) (p0.0001 and p=0.043 respectively). In the gliclazide group, average IMT increased during the follow-up period, but annual change in average IMT was significantly smaller than that of the glibenclamide group (p=0.005). Glibenclamide + metformin or gliclazide also attenuated the progression of maximum IMT, compared with that of glibenclamide (0.041+/-0.105, 0.044+/-0.106, 0.114+/-0.131 mm/year respectively, p=0.029 and p=0.035 respectively). Multivariable regression analysis implied that administration of metformin or gliclazide significantly and independently (p0.05) reduces the progression of average IMT, compared with glibenclamide monotherapy.These data indicate that metformin or gliclazide, rather than glibenclamide, have a potent anti-atherogenic effect in type 2 diabetes.

Objective: This study was conducted to examine whether tissue characterization of the carotid artery wall by determining integrated backscatter (IBS) can identify subjects with a recent history of acute coronary syndrome (ACS) or atherothrombotic infarction (ATI). Research design and methods: The maximum thickness (Max-IMT) and IBS value (corrected-IBS) of the carotid artery intima–media complex were measured ultrasonographically for 132 type 2 diabetic subjects (62.9±8.5 (±S.D.) years old, 87 men and 45 women) with or without cardiovascular diseases. Results: The diabetic patients with recent ACS or ATI had a significantly lower corrected-IBS and higher Max-IMT than those with Max-IMT ≧ 1.1mm but without cardiovascular diseases. The product of Max-IMT and corrected-IBS (IMT-IBS product) of the patients with recent ACS was significantly lower than that of the patients with chronic stable angina. The multiple logistic model showed that only the IMT-IBS product was associated with a recent history of ACS (odds ratio 0.94, P P Conclusions: Diabetic patients who had a recent history of ACS or ATI showed a lower IBS value and higher IMT for their carotid artery. Both the size and tissue characteristics of the carotid plaque may identify subjects with a high risk of cardiovascular disease.

Brain-derived neurotrophic factor (BDNF), a member of the neurotrophins, has been reported to ameliorate hyperglycemia in obese diabetic animal models. To elucidate the mechanism of BDNF on glucose metabolism, we determined the glucose turnover under basal and euglycemic hyperinsulinemic (insulin infusion rate, 54 pmol · kg−1 · min−1) clamp conditions in obese insulin-resistant rats, male Zucker fatty rats, which had been acutely administered a subcutaneous injection of BDNF (20 mg/kg) (n = 9, BDNF) or vehicle (n = 8, vehicle). Under the basal condition, acute administration of BDNF did not affect the blood glucose level, plasma insulin level, rate of glucose disappearance (Rd), and endogenous glucose production (EGP). Under the clamp condition, the glucose infusion rate (GIR) was significantly higher in BDNF than in vehicle (mean ± SD, 61.4 ± 19.1 v 41.4 ± 4.9 μmol · kg−1 · min−1, P

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