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Amino acid metabolites, including branched-chain amino acids (BCAA) and tyrosine (Tyr), affect glucose metabolism. The effects of BCAA on insulin resistance in patients with diabetes seem to conflict with mechanisms determined in animal models and cultured cells. The aim of this study was to clarify the controversy surrounding the effects of BCAA by investigating the physiological effects of BCAA and Tyr on glucose metabolism in healthy community dwellers.We investigated associations among BCAA and Tyr and metabolic parameters in 78 residents (median age, 52 y) of Mie, Japan, who did not have prediabetes, diabetes, or a body mass index30 kg/m(2).Muscle volume, serum BCAA, and Tyr levels were higher in men than in women (n = 32 and 46, respectively; all P 0.0001). Stepwise multiple regression analysis associated BCAA positively with muscle volume (regression coefficient/t/p/95% confidence interval, 281.8/3.7/0.0004/129.7-433.8), fasting blood glucose (FBG; 12699.4/3.22/0.0020/4830.9-20567.8), fasting immunoreactive insulin (IRI; 8505.1/2.75/0.0078/2322.5-14687.6), and homeostasis model assessment of β-cell function (HOMA-β; 893.6/2.58/0.0122/201.8-1585.5), and negatively with the HOMA-insulin resistance (HOMA-IR; -9294.1/-2.89/0.0052/-15711.0 to -2877.1). Tyr positively correlated with fasting IRI (26/2.77/0.0072/7.3-44.7).Insulin sensitivity and muscle volume are positively associated with BCAA in individuals without diabetes. In turn, BCAA correlate with increased FBG and fasting IRI levels. Tyr correlated with fasting IRI, but not with insulin sensitivity.

We have reported that hypertrophic adipocytes release extracellular vesicles (EVs) and the number of circulating adipocyte-derived EVs correlated with insulin and homeostasis model assessment-insulin resistance (HOMA-IR) in a pilot study using obese patients. Here, we explored the association between circulating EV level and various metabolic parameters, including obesity and lipid and glucose metabolisms, among 203 subjects (76 men and 127 women; median age, 54 yr) with or without risk factor for metabolic diseases, who received a 75-g oral glucose tolerance test (OGTT). Circulating EV number was significantly higher in men than in women ( P < 0.001). Circulating EV number in individuals with impaired OGTT pattern was significantly higher compared with those with normal OGTT patterns ( P < 0.05). Multiple regression analysis revealed that circulating EV number correlated most strongly and significantly with elevated triglyceride (TG; t = 8.55, P < 0.001). Additionally, circulating EV number correlated significantly with homeostasis model assessment-β-cell function (HOMA-β; t = 2.38, P < 0.05). Receiver operating characteristic curve revealed that the cutoff value of EV numbers in individuals with elevated serum TG levels (≧150 mg/dl) was identified (136,738 EVs/μl of plasma, P < 0.001, sensitivity 0.842, false-positive rate of 0.257). Perilipin and asialoglycoprotein receptor 1 were detected on a part of isolated circulating EVs, indicating EV release from adipocytes and hepatocytes, which were related to lipid and glucose metabolism. Circulating EVs represent a promising metabolic biomarker for lipid and glucose metabolism and have potential for monitoring metabolic status in humans, including individuals without metabolic risk factors.

In Japan, the incidence of type 2 diabetes mellitus (T2DM) is increasing for several reasons, including increased consumption of sugar-sweetened beverages (SSBs). However, whether SSBs cause T2DM by excess of energy production resulting in obesity remains unclear. Therefore, the present study was designed to evaluate the effects of SSB intake on the development of T2DM in subjects with impaired glucose tolerance (IGT). Ninety-three subjects (30 males and 63 females) with IGT aged 40-69 y and residing in the Mihama district (southern Mie Prefecture, Japan) were included in the study. The mean observational period was 3.6 y. All subjects underwent the 75-g oral glucose tolerance test (OGTT) and completed a lifestyle questionnaire survey related to SSB intake. OGTT results and SSB intake were evaluated before and after the observational period. In addition, the correlation between SSB intake and development of T2DM was investigated. Of the 93 subjects, 20 (21.5%) developed T2DM (T2DM group) and demonstrated a significantly high SSB intake compared with the group that did not develop the disease (non-T2DM group). The odds ratio for the incidence of T2DM based on SSB intake was 3.26 (95% confidence interval, 1.17-9.06). The body mass index (BMI; kg/m(2)) and the homeostasis model assessment for insulin resistance (HOMA-R) values was significantly higher in the T2DM group than in the non-T2DM group, while the insulinogenic indices were significantly lower in the former than in the latter group. The sum of insulin secretion levels during OGTT was not significantly different between groups. SSB intake correlated with the predisposition for developing T2DM, possibly by influencing body weight, insulin resistance, and the ability of the pancreatic beta cells to effectively compensate for the insulin resistance.

Summary Background Limited evidence suggests that multifactorial interventions for control of glucose, blood pressure, and lipids reduce macrovascular complications and mortality in patients with type 2 diabetes. However, safe and effective treatment targets for these risk factors have not been determined for such interventions. Methods In this multicentre, open-label, randomised, parallel-group trial, undertaken at 81 clinical sites in Japan, we randomly assigned (1:1) patients with type 2 diabetes aged 45–69 years with hypertension, dyslipidaemia, or both, and an HbA 1c of 6·9% (52·0 mmol/mol) or higher, to receive conventional therapy for glucose, blood pressure, and lipid control (targets: HbA 1c 1c 1c , and history of cardiovascular disease. Neither patients nor investigators were masked to group assignment. The primary outcome was occurrence of any of a composite of myocardial infarction, stroke, revascularisation (coronary artery bypass surgery, percutaneous transluminal coronary angioplasty, carotid endarterectomy, percutaneous transluminal cerebral angioplasty, and carotid artery stenting), and all-cause mortality. The primary analysis was done in the intention-to-treat population. This study is registered with ClinicalTrials.gov, number NCT00300976. Findings Between June 16, 2006, and March 31, 2009, 2542 eligible patients were randomly assigned to intensive therapy or conventional therapy (1271 in each group) and followed up for a median of 8·5 years (IQR 7·3–9·0). Two patients in the intensive therapy group were found to be ineligible after randomisation and were excluded from the analyses. During the intervention period, mean HbA 1c , systolic blood pressure, diastolic blood pressure, and LDL cholesterol concentrations were significantly lower in the intensive therapy group than in the conventional therapy group (6·8% [51·0 mmol/mol] vs 7·2% [55·2 mmol/mol]; 123 mm Hg vs 129 mm Hg; 71 mm Hg vs 74 mm Hg; and 85 mg/dL vs 104 mg/dL, respectively; all p vs 283 [22%] in the conventional therapy group, p vs 129 [10%], p=0·0001), the frequencies of major adverse events did not differ between groups. Interpretation Our results do not fully support the efficacy of further intensified multifactorial intervention compared with current standard care for the prevention of a composite of coronary events, cerebrovascular events, and all-cause mortality. Nevertheless, our findings suggest a potential benefit of an intensified intervention for the prevention of cerebrovascular events in patients with type 2 diabetes. Funding Ministry of Health, Labour and Welfare of Japan, Asahi Kasei Pharma, Astellas Pharma, AstraZeneca, Bayer, Boehringer Ingelheim, Bristol-Myers Squibb, Daiichi Sankyo, Eli Lilly, GlaxoSmithKline, Kissei Pharmaceutical, Kowa Pharmaceutical, Mitsubishi Tanabe Pharma, Mochida Pharmaceutical, MSD, Novartis Pharma, Novo Nordisk, Ono Pharmaceutical, Pfizer, Sanwa Kagaku Kenkyusho, Shionogi, Sumitomo Dainippon Pharma, Taisho Toyama Pharmaceutical, and Takeda.

Aims: Chronic hepatitis C virus (HCV) infection is often associated with glucose metabolic disorders and iron overload. It has recently been shown that reactive oxygen species (ROS) increase gluconeogenesis in hepatocytes through the forkhead box-containing protein O subfamily-1 (FOXO1)-dependent pathway. The aim of this study is proving a cause-and-effect relationship between iron-mediated ROS production and insulin resistance (IR) in chronic hepatitis C (CH-C) patients. Methods: The study included 42 patients with CH-C (22 males and 20 females, median age 53 years). Homeostasis model assessment of insulin resistance (HOMA-IR) value was assessed for each patient at entry. Gene expression levels in the biopsied liver tissues were determined by quantitative reverse transcription-polymerase chain reaction (RT- PCR). In addition, the effect of ROS on gluconeogenesis was assessed using HepG2 cells treated with a well-known ROS generator, diethylmaleate (DEM). Results: The serum ferritin levels were significantly correlated with the serum aspartate aminotransferase level, alanine aminotransferase level, HOMA-IR value, grade of fatty accumulation, total hepatic iron score, and 8-OH-deoxy-2’-guanosine (8-OHdG)-positive cell count. FOXO1 expression was correlated with 8-OHdG-positive cell count, phosphoenolpyruvate carboxykinase (PEPCK) expression, and HOMA-IR. In HepG2 cells, the gene transcription of FOXO1 and PEPCK was increased by DEM treatment, which was associated with an increase in non-phosphorylated FOXO1 protein in the nuclear fraction. Conclusions: Iron-mediated ROS production enhances gluconeogenesis through the FOXO1-mediated pathway and is an affecting factor to IR in patients with CH-C.

Diabet. Med. 29, e41–e46 (2012) Abstract Aims Dehydroepiandrosterone exerts a protective effect against cardiovascular diseases. However, the relationship of dehydroepiandrosterone with the anticoagulant factor activated protein C, generated by the thrombin–thrombomodulin complex on vascular endothelial cells, remains unknown. This study aimed at studying the relationship between dehydroepiandrosterone and activated protein C generation in patients with Type 2 diabetes. Methods Sixty-two male patients with Type 2 diabetes were enrolled in this study. Data obtained from 40 healthy male subjects were used as controls. The plasma levels of dehydroepiandrosterone, the activated protein C–protein C inhibitor complex, high-sensitivity C-reactive protein and monocyte chemoattractant protein-1 were measured by enzyme immunoassays. Carotid intima-media thickness was measured by ultrasonography. Results The plasma levels of dehydroepiandrosterone (5.15 ± 2.81 vs. 3.76 ± 2.16 ng/ml; P

Cytokines secreted by T cells play a pivotal role in the pathogenesis of lung injury and fibrosis, and the transcription factors nuclear factor (NF)-kappaB and activator protein (AP)-1 are involved in the expression of cytokines from T cells during lung injury.We assessed the potential therapeutic effect of SP100030, a specific inhibitor of T-cell NF-kappaB and AP-1 in lung fibrosis.The effect of SP100030 was evaluated using a mouse model of chronic lung fibrosis.Mice treated with SP100030, as compared with untreated mice, had significantly less cachexia and less lung injury and had decreased levels of inflammatory cytokines and growth factors, decreased activation of coagulation activation, and decreased collagen deposition in the lung. The inhibitory activity of SP100030 was dose dependent and was effective in acute and chronic phases of lung fibrosis. SP100030 inhibited the activation of the protein kinase C-isoform in T-cell lines and suppressed NF-kappaB-driven cytokine expression in CD4(+) and CD8(+) T cells.These results suggest that the specific inhibition of NF-kappaB could be useful for the treatment of lung fibrosis.

Aims Activated protein C (APC) is a key regulator of the clotting system and immune responses. We studied the relationship between the degree of atherosclerosis as measured by the intima-media thickness (IMT) of carotid artery and APC generation in Type 2 diabetic patients. Methods Eighty-seven Type 2 diabetic patients and 35 control subjects participated. APC generation was assessed by the plasma APC–protein C inhibitor complex (APC-PCI) levels and the mean IMT of carotid artery was measured by ultrasonography. The plasma levels of the thrombin–anti-thromobin complex (TAT) and platelet-derived growth factor (PDGF) were measured by enzyme-linked immunoassays. Results Plasma TAT levels were significantly higher in diabetic patients [2.03 (1.12, 2.56) ng/ml, median (25th, 75th percentile)] compared with control subjects [0.85 (0.55, 2.08) ng/ml, P

We investigated the plasma levels of thrombin-activatable fibrinolysis inhibitor (TAFI), plasminogen activator inhibitor-1 (PAI-1) and their relation with clinical and metabolic parameters in non-obese type 2 diabetic patients. The plasma levels of TAFI and PAI-1 were evaluated in 47 non-obese type 2 diabetic patients and 31 normal subjects. The intra-abdominal visceral and subcutaneous fat areas were measured by computed tomography (CT). The degree of insulin resistance was evaluated by the euglycemic-hyperinsulinemic clamp technique using artificial pancreas. The plasma levels of TAFI (169.0+/-108.8% versus 103.7+/-52.3%; p

To investigate the direct relationship of oxidative stress with obesity and insulin resistance in men, we measured the plasma levels of 8-epi-prostaglandin F2α (PGF2α) in 14 obese and 17 nonobese men and evaluated their relationship with body mass index; body fat weight; visceral, sc, and total fat areas, measured by computed tomography; and glucose infusion rate during a euglycemic hyperinsulinemic clamp study. Obese men had significantly higher plasma concentrations of 8-epi-PGF2α than nonobese men (P < 0.05). The plasma levels of 8-epi-PGF2α were significantly correlated with body mass index (r = 0.408; P < 0.05), body fat weight (r = 0.467; P < 0.05), visceral (r = 0.387; P < 0.05) and total fat area (r = 0.359; P < 0.05) in all (obese and nonobese) men. There was also a significant correlation between the plasma levels of 8-epi-PGF2α and glucose infusion rate in obese men (r = −0.552; P < 0.05) and all men (r = −0.668; P < 0.01). In all subjects, the plasma levels of 8-epi-PGF2α were significantly correlated with fasting serum levels of insulin (r = 0.487; P < 0.01). In brief, these findings showed that the circulating levels of 8-epi-PGF2α are related to adiposity and insulin resistance in men. Although correlation does not prove causation, the results of this study suggest that obesity is an important factor for enhanced oxidative stress and that this oxidative stress triggers the development of insulin resistance in men.

OBJECTIVE—The purpose of this study was to investigate the association between visceral adiposity or triglyceride (TG) metabolism and insulin resistance in metabolically obese, normal weight (MONW) Japanese individuals with normal glucose tolerance. RESEARCH DESIGN AND METHODS—We evaluated body fat areas, lipid profiles, and the glucose infusion rate (GIR) during a euglycemic-hyperinsulinemic clamp study in 20 MONW subjects (BMI RESULTS—MONW subjects showed a significant increase in fasting serum levels of TG (P < 0.01) and a decrease in GIR (P < 0.01) compared with normal subjects. There were significant correlations between visceral fat areas (r = −0.563, P < 0.01) or serum levels of TG (r = −0.474, P < 0.05) and GIR in MONW subjects. Multiple regression analyses showed that visceral fat areas (F = 7.702, P < 0.02) and serum levels of TG (F = 7.114, P < 0.05) were significantly associated with GIR in all (MONW and normal) subjects. CONCLUSIONS—Increased visceral fat and serum levels of TG are associated with insulin resistance in Japanese MONW subjects with normal glucose tolerance. Excess visceral fat and elevated TG levels may play important roles in the development of insulin resistance in Japanese MONW subjects with normal glucose tolerance.

Hypofibrinolysis is a common finding in patients with diabetes mellitus and a risk factor for diabetic nephropathy. Recently, a new potent inhibitor of fibrinolysis, the thrombin-activatable fibrinolysis inhibitor (TAFI), has been isolated from human plasma. The possibility that TAFI also participates in the mechanism of hypofibrinolysis has not been appraised in diabetic patients with microalbuminuria. In the present study, we investigated the plasma levels of TAFI and its relation to urinary albumin excretion in normotensive diabetic patients with normo- and microalbuminuria. Thirty-nine normotensive nonobese type 2 diabetic patients (27 with normoalbuminuria, 12 with microalbuminuria) and 20 age-matched normal subjects were enrolled in this study. The plasma level of thrombin-antithrombin complex was significantly increased (22.1 +/- 2.6 vs. 8.3 +/- 1.0 nmol/liter; P < 0.05), whereas the D-dimer/thrombin-antithrombin complex ratio was significantly decreased (15.7 +/- 1.4 vs. 26.5 +/- 2.2; P < 0.05), showing the occurrence of hypercoagulability and hypofibrinolysis in diabetic patients. The plasma level of TAFI in diabetic patients was significantly elevated, compared with normal subjects (147.4 +/- 11.6 vs. 99.5 +/- 4.9%; P < 0.05). The plasma level of TAFI in diabetic patients with microalbuminuria was significantly higher than the level in diabetic patients with normoalbuminuria (194.1 +/- 24.5 vs. 128.8 +/- 12.3%; P < 0.02) or normal subjects (194.1 +/- 24.5 vs. 99.5 +/- 4.9%; P < 0.005). Univariate analysis showed that the plasma TAFI levels are significantly and proportionally correlated with urinary albumin excretion rate (r = 0.58; P < 0.005) and with plasma soluble thrombomodulin level, a marker of endothelial cell damage, in all diabetic patients (r = 0.42; P < 0.01). These data suggest that increased plasma level of TAFI may be involved in the mechanism of vascular endothelial damage in patients with type 2 diabetes mellitus.

To clarify whether homeostasis model assessment (HOMA IR) and quantitative insulin sensitivity check index (QUICKI) may be indicators of insulin resistance in elderly patients with type 2 diabetes mellitus, their relationship with the glucose infusion rate during the euglycemic hyperinsulinemic clamp study (clamp IR) was assessed. This study comprised 56 Japanese patients with type 2 diabetes mellitus; of these, 28 were 70 yr of age or older (group 1) and 28 were less than 70 yr of age (group 2). Their blood sugars were in poor control (fasting plasma glucose levels: group 1, 9.0 2.6 mmol/liter; group 2, 8.9 2.3 mmol/liter; hemoglobin A1c: group 1, 9.5 2.0%; group 2, 9.2 1.7%). Log-transformed HOMA IR was significantly correlated with the clamp IR in group 2 patients (r 0.51, P < 0.01), but not in group 1 patients (r 0.28, P 0.15). There was a significant positive correlation between QUICKI and clamp IR in group 2 patients (r 0.50, P < 0.01). However, no significant correlation was observed between QUICKI and clamp IR in group 1 patients (r 0.31, P 0.12). There was a significant correlation between log-transformed HOMA IR (r 0.37, P < 0.01) or QUICKI (r 0.37, P < 0.01) and clamp IR when both groups were combined. In conclusion, neither HOMA IR nor QUICKI should be used as an index of insulin resistance in elderly patients with poorly controlled type 2 diabetes mellitus. The results of this study suggest the need for developing a new noninvasive method for evaluating insulin resistance in those patients. (J Clin Endocrinol Metab 87: 5332–5335, 2002)

Troglitazone has been shown to improve peripheral insulin resistance in type 2 diabetic patients and animal models. We examined the effect of troglitazone on the expression of glucose transporter 4 (GLUT4) in muscle and adipose tissue from Otsuka Long-Evans Tokushima Fatty (OLETF) rat, an animal model of obese type 2 diabetes mellitus. In addition, the effects of troglitazone on GLUT4 translocation and on glucose transport activity in adipocytes were also evaluated. Muscle and adipose tissues were isolated from 35-week-old male troglitazone-treated and untreated OLETF rats at a dose of 150 mg/kg per day for 14 days. In skeletal muscle, the protein and mRNA levels of GLUT4 were not significantly different between OLETF and control rats and they were not affected by troglitazone. On the other hand, GLUT4 protein and mRNA levels in adipose tissue from OLETF rats were significantly decreased (P

We investigated the relationship of the A/G variant of the tumor necrosis factor-alpha (TNF-alpha) gene promoter at position -308 with insulin resistance and abdominal fat distribution in type 2 diabetic patients in the Japanese population. The TNF-alpha polymorphism was evaluated by polymerase chain reaction-restriction fragment length polymorphism in 142 healthy volunteers and 132 type 2 diabetic patients. Insulin sensitivity was assessed by homeostasis model assessment (HOMA) index in healthy subjects and hyperinsulinemic euglycemic clamp in type 2 diabetic patients. Abdominal fat distribution was evaluated by computed tomography (CT) scanning in diabetic patients. The TNF-alpha polymorphism was detected in three healthy volunteers and three type 2 diabetic patients, all of them being heterozygotes. There was no significant difference in allele frequencies of the -308 polymorphism between healthy subjects (0.0106) and type 2 diabetic patients (0.0114). HOMA index was no significant difference between healthy subjects with and without polymorphism (1.09 +/- 0.03 vs. 1.02 +/- 0.05). Glucose infusion rate (GIR), an index of insulin sensitivity, was not significantly different between diabetic patients with and without TNF-alpha polymorphism (40.4 +/- 4.1 vs. 45.0 +/- 1.8 micromol/kg per min). Moreover, no remarkable effect of TNF-alpha polymorphism on abdominal fat distribution was observed in diabetic patients. These results suggest that A/G heterozygotes of the TNF-alpha gene promoter at position -308 play no major role in the pathogenesis of insulin resistance or abdominal fat distribution in Japanese type 2 diabetic patients.

Hypofibrinolysis is a common finding in patients with diabetes mellitus (DM) and obesity and a risk factor for the development of cardiovascular disease. Recently, a new potent inhibitor of fibrinolysis, the thrombin-activatable fibrinolysis inhibitor (TAFI) has been isolated and characterized from human plasma. The present study was undertaken to assess the activity and circulating level of TAFI and its relation to fibrinolytic function and obesity in patients with type 2 DM. Fifty-seven patients with type 2 DM (38 men, 19 women) were enrolled in this study. DM patients were categorized in age-matched obese [body mass index (BMI) ≥ 25] and nonobese (BMI < 25) groups. The plasma concentration and activity of TAFI were significantly (P < 0.05) higher in DM patients than in healthy controls. The plasma levels and activity of TAFI were significantly (P < 0.05) elevated in obese DM patients compared with nonobese DM and nonobese healthy subjects. RT-PCR demonstrated the expression of TAFI in human adipose tissue and in human endothelial cells. The plasma levels of TAFI were independently and significantly correlated with glucose intolerance (HbA1c), with obesity (BMI, visceral fat area), and with an indicator of insulin resistance (glucose infusion rate). This study showed that increased circulating level of TAFI may be an important causative factor of hypofibrinolysis in patients with type 2 diabetes, obesity and insulin resistance.

Objective The aim of this study was to assess the significance and degree of correlation between the intake of fish oil, magnesium (Mg), and zinc (Zn) and metabolic parameters. Methods Correlation coefficients among nutrient intake and physical and laboratory parameters were determined using Spearman's rho (ρ) test or a multiple regression model among Japanese individuals (male:female, 37:66; median age, 55 y) who completed a semiquantitative food questionnaire and underwent testing for diabetes. Individuals with diabetes were excluded. Results Spearman's test revealed several weak but significant correlations between intake of fish oil including ω-3 polyunsaturated fatty acids (PUFAs) and various metabolic parameters. The test showed that Zn intake in women significantly correlated with reduced systolic blood pressure (SBP), alanine aminotransferase (ALT), γ-glutamyl transpeptidase (γ-GPT), and homeostasis model assessment–insulin resistance (HOMA-IR). Multivariate analysis revealed that intake of fish oil, eicosapentaenoic acid (EPA), and Zn was significantly associated with increased serum levels of high-density lipoprotein cholesterol (HDL-C; fish oil versus HDL-C, P = 0.0438; 95% confidence interval [CI], 0.0055–0.3724; EPA versus HDL-C, P = 0.0439; 95% CI, 0.0053–0.3724; Zn versus HDL-C, P = 0.0041; 95% CI, 0.0890–0.4609). Multivariate analysis revealed that ω-3 PUFAs were associated with decreased serum ALT levels (P = 0.0240; 95% CI, −5.000 to −0.0367) and that Zn correlated with SBP (P = 0.0239; 95% CI, −0.5149 to −0.0377) in women. Conclusion Intake of fish oil, Mg, and Zn was associated with some metabolic parameters. Abundant intake of fish oil including ω-3 PUFAs and Zn can exert antiarteriosclerotic effects through increasing serum levels of HDL-C. ω-3 PUFAs can reduce liver inflammation and Zn can reduce SBP in women.

To investigate the relationship between peripheral blood levels of agouti-related protein (AGRP) and various parameters of obesity, we measured the plasma level of AGRP in 15 obese and 15 nonobese men and evaluated its relationship with body mass index (BMI), body fat weight, and visceral, sc, and total fat areas measured by computed tomography, fasting insulin levels, glucose infusion rate during an euglycemic hyperinsulinemic clamp study, serum leptin, and plasma alpha-MSH. Obese men had significantly higher plasma concentrations of AGRP than nonobese men (P0.01). Univariate analysis showed that the plasma levels of AGRP are proportionally correlated with BMI, body fat weight, and sc fat area in obese men (BMI: r = 0.732, P0.01; body fat weight: r = 0.603, P0.02; sc fat area: r = 0.668, P0.01) and in all men (BMI: r = 0.839, P0.0001; body fat weight: r = 0.818, P0.0001; sc fat area: r = 0.728, P0.0001). In all men, the plasma levels of AGRP were significantly correlated with the visceral fat area (r = 0.478, P0.01), total fat area (r = 0.655, P0.0001), fasting insulin level (r = 0.488, P0.01), glucose infusion rate (r = -0.564, P0.01), serum level of leptin (r = 0.661, P0.0001), and the plasma level of alpha-MSH (r = 0.556, P0.01). In all subjects, multiple regression analysis showed that the plasma levels of AGRP are significantly (F = 15.522, r = 0.801, P0.03) correlated with the plasma levels of alpha-MSH, independently from the total fat area. However, the correlation between plasma levels of AGRP and serum levels of leptin was found to be dependent on the total fat area. In brief, these findings showed that the circulating levels of AGRP are increased in obese men and that they are correlated with various parameters of obesity. Although correlation does not prove causation, the results of this study suggest that peripheral AGRP may play a role in the pathogenesis of obesity.

OBJECTIVE— To investigate the usefulness of the homeostasis model assessment as an index of insulin resistance (HOMA-IR) for evaluating the clinical course of patients with type 2 diabetes. RESEARCH DESIGN AND METHODS— The usefulness of HOMA-IR and its relationship with insulin resistance assessed by the hyperinsulinemic-euglycemic clamp study (clamp IR) were evaluated in 55 Japanese patients with type 2 diabetes before and after treatment. The patients were subjected to diet (∼1,440-1,720 kcal/day) and exercise therapy (walking 10,000 steps daily) for 6 weeks during their hospitalization. RESULTS— Univariate regression analysis disclosed a significant correlation between log-transformed HOMA-IR and log-transformed clamp IR before (r = -0.613, P < 0.0001) and after(r = -0.734, P < 0.0001) treatment. Neither the slopes(-0.71 ± 0.12 vs. -0.79 ± 0.09, F = 0.25, P =0.61) nor the intercepts (y-intercept = 1.67 vs. 1.70, x-intercept = 2.36 vs. 2.15, F = 0.02, P = 0.88) of the regression lines between HOMA-IR and clamp IR were significantly different before and after treatment. There was a significant correlation between the decrease in log-transformed HOMA-IR and the increase in clamp IR during treatment (r = -0.617, P < 0.0001). CONCLUSIONS— HOMA-IR may constitute a useful method not only for diagnosing insulin resistance, but also for follow-up during the treatment of patients with type 2 diabetes.

OBJECTIVE: The role of α-melanocyte stimulating hormone (MSH) in obesity has been well-documented. However, circulating α-MSH concentrations in obese men and their relationship with clinical indicators of obesity and glucose metabolism have not as yet been evaluated. METHODS: We measured the plasma concentrations of α-MSH in 15 obese and 15 non-obese male subjects. The relationship of the plasma concentrations of α-MSH with body mass index (BMI), body fat mass (measured by bioelectric impedance), body fat distribution (measured by computed tomography), insulin levels, insulin resistance (assessed by the glucose infusion rate (GIR) during an euglycemic hyperinsulinemic clamp study) and with the serum concentrations of leptin and TNF-α were also evaluated. RESULTS: In obese men, the plasma α-MSH concentrations were significantly increased compared with those in non-obese men (P

Summary Aim To determine the relationship of the polymorphism at codon 54 of the intestinal fatty acid binding protein gene (FABP2) with insulin resistance and susceptibility to Type 2 diabetes mellitus (DM) in the Japanese population. Methods We evaluated the polymorphism by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in 150 Type 2 DM patients and 147 healthy control subjects. The frequency of alleles encoding threonine (Thr54) and alanine (Ala54) at codon 54 of FABP2 in Type 2 DM patients was compared with that of healthy controls. Insulin sensitivity was assessed by the hyperinsulinaemic euglycaemic clamp in Type 2 DM patients with Ala54 homozygotes, Ala54/Thr54 heterozygotes and Thr54 homozygotes and by homeostasis model assessment (HOMA) in the nondiabetic group. Results The frequency of alleles encoding Ala54 and Thr54 was 0.59 and 0.41 in Type 2 DM patients, respectively, similar to that observed in nondiabetic controls (0.64 for Ala54 and 0.36 for Thr54). Insulin sensitivity was not significantly different between subjects with and without Thr54 allele either within the DM group or healthy controls. Conclusions The allele encoding threonine in the FABP2 does not predispose to Type 2 DM or insulin resistance in the Japanese population Diabet. Med. 16, 119–124 (1999)

We investigated that the association of MCP-1 polymorphism at position −2518 with insulin sensitivity and insulin secretion by measuring the fasting and post-challenge glucose and insulin levels during 75 g OGTT in 409 non-diabetic Japanese subjects. The blood sampling was performed before glucose loading and after 30 and 120 min. Polymorphism was evaluated by PCR-RFLP method by genomic DNA isolated from peripheral blood leukocytes. The genotype distribution was 44.8% for G/G, 46.0% for G/A and 9.2% for A/A. The plasma glucose levels were significantly increased in A/A as compared to G/G (p < 0.05), but it was not compared with G/A at 120 min. The serum insulin levels were significantly increased in A/A as compared to G/A (p < 0.05) or G/G (p < 0.05) at 30 min. Moreover, the serum insulin levels in A/A were significantly increased compared with G/A (p < 0.02) or G/G (p < 0.005) at 120 min. Elevation in post-challenge glucose (120 min) and insulin levels (30 and 120 min) suggests that reduced insulin sensitivity during glucose loading occurs in subjects with A/A polymorphism. The present study demonstrates that the A/A polymorphism of the MCP-1 gene at position −2518 is associated with insulin resistance during glucose loading in non-diabetic Japanese subjects.

To clarify the significance of the serum levels of tumor necrosis factor-alpha (TNF-alpha) in the mechanism of insulin resistance, we studied 12 obese patients with noninsulin-dependent diabetes mellitus (NIDDM). We evaluated the relationship of TNF-alpha levels with the visceral, subcutaneous, and total fat areas measured by computed tomography (CT), and with insulin resistance evaluated by the glucose infusion rate (GIR) observed during an euglycemic hyperinsulinemic clamp study. Controls consisted of 12 normal subjects and 12 nonobese patients with NIDDM. TNF-alpha levels were measured using a high sensitivity enzyme-linked immunosorbent assay. Following admission, all patients with NIDDM participated in a 4-week program of diet and exercise. After this treatment, we evaluated the relationship of the serum levels of TNF-alpha with the area of body fat, the GIR, and the resultant change in the TNF-alpha level. Serum levels of TNF-alpha in the obese patients with NIDDM significantly exceeded those observed in normal subjects (P < 0.01) or in the nonobese patients with NIDDM (P < 0.01). Serum levels of TNF-alpha in obese NIDDM patients showed a significant positive correlation with the area of visceral fat before (r = 0.662, P < 0.03) and after (r = 0.508, P < 0.05) the treatment; similar correlation was observed in all patients with NIDDM before (r = 0.537, P < 0.02) and after (r = 0.430, P < 0.05) the treatment. Serum levels of TNF-alpha in obese NIDDM patients showed a significant negative correlation with GIR after the treatment (r = -0.595, P < 0.05). Serum levels of TNF-alpha were significantly reduced in the obese patients with NIDDM after the treatment (P < 0.01), while those in the nonobese NIDDM patients were unchanged. These results suggest that serum TNF-alpha levels may play an important role in mechanism of insulin resistance associated with obesity.

Thickening of the basement membrane and other structural alterations of the vascular walls occur frequently in patients with diabetes. The vascular response to atrial natriuretic peptide (ANP) is also altered in these patients. Abnormal vascular response in diabetes may be due to alteration of vascular physicochemical properties induced by accumulation of components of vascular basement membrane. The aim of this study was to evaluate the relationship between circulating levels of the 7 S domain of type IV collagen (7 S-collagen), and ANP in normotensive type 2 diabetic patients with or without retinopathy. Forty-one normotensive type 2 diabetic patients (n = 19 with and n = 22 without retinopathy) and 18 age-matched control subjects participated in the study. Serum 7 S-collagen and plasma ANP levels were measured by radioimmunoassays. Serum 7 S-collagen (4.4 +/- 0.1 vs 3.5 +/- 0.1 ng/ml; p < 0.01) levels and plasma ANP (20.8 +/- 1.0 vs 15.5 +/- 1.0 pg/ml; p < 0.01) were significantly higher in diabetic patients than in normal subjects. Serum 7 S-collagen increased significantly in diabetic patients without retinopathy compared with normal subjects (4.1 +/- 0.1 vs 3.5 +/- 0.1 ng/ml; p < 0.01). Diabetic patients with retinopathy showed significantly higher circulating concentrations of 7 S-collagen (4.6 +/- 0.1 vs 4.1 +/- 0.1 ng/ml; p < 0.01) and ANP (22.9 +/- 1.4 vs 18.9 +/- 1.3 pg/ml; p < 0.05) than those without retinopathy. There was a significant and positive correlation (r = 0.51, p < 0.01) between the circulating levels of 7 S-collagen and ANP in all patients. The results of this investigation showed that increased circulating levels of ANP correlate with the abnormal metabolism of the vascular basement membrane observed in diabetic patients with microangiopathy.

The in vitro effect of thyroid hormones on glucose transport in insulin-stimulated muscle cells or adipocytes is still unclear. The objective of the present study was to assess the direct effect of 3,3′,5-triiodothyronine (T3) on glucose transport and on the translocation of insulin-regulatable glucose transporter (GLUT4) in insulinstimulated rat adipocytes. This evaluation was performed using an in vitro assay to avoid the well-known systemic effects of this hormone (e.g.: hyperinsulinemia). Adipocytes were isolated from epididymal adipose tissue of Sprague-Dawley rats. Glucose transport assay and immunoblot analysis of GLUT4 were carried out in insulin-stimulated and unstimulated adipocytes after treating with or without T3. The results were as follows; 1) T3 inhibited the glucose transport in insulin-stimulated and unstimulated adipocytes in a dose-dependent manner. 2) T3 decreased the maximal response level (Vmax) but did not alter the sensitivity (Km) of glucose transport to insulin. 3) T3 did not affect the translocation of GLUT4 from the intracellular pool to the plasma membrane. We concluded that T3 inhibits the glucose transport in insulinstimulated adipocytes in a post-receptor level without affecting the translocation of GLUT4 from the intracellular pool to the plasma membrane. This suggests that T3 acts by decreasing the intrinsic activity or the accessibility of GLUT4 in the plasma membrane.

A 24-week study was conducted to evaluate the effects of the dihydropyridine calcium channel blocker nilvadipine on urinary albumin excretion in eight microalbuminuric hypertensive patients with non-insulin-dependent (type II) diabetes mellitus. Blood pressure and urinary albumin excretion measurements before the administration of nilvadipine (8 mg) were compared with those after 4, 8, 12 and 24 weeks of treatment. No significant changes were observed in the mean values of haemoglobin A1C. Systolic blood pressure was significantly reduced from 174 ± 23 mmHg before treatment to 144 ± 13 mmHg after 24 weeks of treatment ( P < 0.02). Diastolic blood pressure was significantly reduced from 93 ± 11 mmHg at baseline to 79 ± 8 mmHg after 24 weeks of treatment ( P < 0.05). Urinary albumin excretion was significantly reduced from 65.4 ± 37.4 mg/g creatinine at baseline to 51.6 ± 41.1 mg/g creatinine ( P < 0.05) after 4 weeks, and to 39.1 ± 26.9 mg/g creatinine ( P < 0.02) after 24 weeks of treatment. These data suggest that in hypertensive microalbuminuric patients with non-insulin-dependent diabetes mellitus, treatment of hypertension with the calcium blocker nilvadipine may slow the progression of diabetic nephropathy.

The correlation between the degree of sympathetic denervation measured through 123I-MIBG Myocardial Scintigraphy and Power Spectral Analysis of consecutive R-R records was investigated in order to evaluate their potential application for the assessment of myocardial autonomic neuropathy in patients with diabetes mellitus. This study comprised 42 patients with Type 2 diabetes. Low frequency (0.02-0.09 Hz) components of the power spectral density were measured as markers of sympathetic activity. The myocardial uptake of 123I-MIBG was measured by using the single photon emission computed tomography (SPECT) and the early and delayed images were recorded. Scoring from 0 to 3 of the 123I-MIBG uptake of various cardiac segments (7) was performed and the total uptake was calculated. The washout rate in the whole myocardium was determined. The values obtained in the group with diabetic autonomic neuropathy (DAN) without orthostatic hypotension (OH) were significantly lower as compared to those of the (DAN (-)) group in the delayed images. The washout rate of the OH (-) group was also significantly higher than the DAN (-) group. There was significant difference between the images and the washout rate of OH (+) and OH (-) groups. There was a significant correlation between Power Spectral Analysis and SPECT (early, delayed images, and washout rate). Of these, the delayed image showed the strongest correlation (r = 0.55, p < 0.01). Further, the QTc interval showed a significant inverse correlation with the delayed image (r = -0.44, p < 0.05). In conclusion, these results suggest that the cardiac 123I-MIBG scintigraphy could be a useful method for the assessment of the myocardial autonomic neuropathy in patients with diabetes mellitus.

Endothelial nitric oxide synthase (eNOS) catalyzes NO production in vascular endothelial cells, and NO regulates local blood flow by inducing vasodilation (1). Enhancement of skeletal muscle glucose uptake occurs during elevation of muscle blood flow, which is induced by increased eNOS expression and activated by insulin stimulation (2–4). It was previously reported that low production of NO in eNOS knockout mice causes reduction of insulin-induced blood flow and glucose uptake in whole body (5). These findings suggest that eNOS plays an important role in the regulation of insulin-induced glucose uptake in whole body. Polymorphism in eNOS exon 7 with G→T conversion at nucleotide position 894 results in amino acid substitution of glutamic acid for aspartic acid in amino acid residue 298 (Glu298Asp). Structural alteration in this variant affects the susceptibility to cleavage and reduces activity of this enzyme (6,7). Dysfunction of eNOS by this polymorphism may cause reduction of insulin-induced blood flow and glucose uptake. It was recently demonstrated that insulin secretion and sensitivity could be assessed by 75-g oral glucose tolerance test (8,9). Therefore, we examined the association of this polymorphism with fasting and postchallenge glucose and insulin levels …

Although it has been firmly established that D-glucose inhibits glucagon secretion from pancreatic A cells, the regulatory mechanism of glucagon secretion by D-glucose has not been elucidated. To study this regulatory mechanism by D-glucose, the effects of hexoses and their derivatives on glucagon secretion from the A cells of isolated perfused rat pancreas were investigated. When these cells were perfused with D-glucose, D-fructose, D-sorbitol, D-galactose, 2-deoxy-D-glucose, D-gluconic acid sodium salt and D-glucosamine HCl salt, glucagon secretion was significantly inhibited. None of the hexoses or their derivatives tested were found to stimulate glucagon secretion. The effects of these sugars on glucagon secretion were independent of their metabolism in the cells. From the findings that the sugars both metabolized and unmetabolized in the cells demonstrated comparable inhibition of glucagon secretion from the isolated perfused rat pancreas, it is speculated that the recognition system for these sugars may be probably present on the A cell membrane and responsible for mediating these inhibitory effects of glucagon secretion.

The effects of fluorescein isothiocyanate II (FITC) on the actions of insulin in rat adipocytes were studied. When adipocytes were incubated with FITC at pH 7.4 (2 mM agent, 8 min), the cells were completely deprived of their specific insulin-binding activity and rendered unresponsive to the hormone. The effect of FITC on the insulin-binding activity was milder at pH 9.0, and cAMP phosphodiesterase in cells exposed to FITC at pH 9.0 was maximally stimulated if the insulin concentration was increased to 100 nM. Under identical conditions, however, glucose transport activity was rendered not only less sensitive but also less responsive to the hormone. When FITC was added to cells after insulin at pH 9.0, the glucose transport activity that had been stimulated by the hormone was considerably reduced. This reduction was largely, but not entirely, prevented if the cells were deprived of ATP, suggesting that FITC (a) elicited the ATP-dependent reversal of the hormonal effect and, simultaneously, (b) mildly inhibited the transport activity per se. Western blot assay of GLUT-4 (a major isoform of glucose transporter in adipocytes) indicated that FITC (a) partially blocked insulin-dependent translocation of GLUT-4 from the intracellular site to the plasma membrane while it (b) induced a mild "insulin-like" effect. It is concluded that FITC at pH 9.0 (a) renders both glucose transport and phosphodiesterase activities less insulin sensitive presumably by modifying the cellular hormone receptor and (b) makes glucose transport activity less responsive to insulin presumably by (i) blocking hormone-dependent translocation of glucose transporter and (ii) mildly inhibiting intrinsic glucose transport activity.

We evaluated the effect of troglitazone (given orally 400 mg/day) on glucose intolerance and on the plasma levels of tumour necrosis factor-alpha (TNF-alpha) in 12 obese patients with type 2 diabetes for 12 weeks. Troglitazone significantly decreased fasting plasma glucose, serum C-peptide, serum insulin and HbA1c levels. Plasma levels of TNF-alpha were significantly reduced by troglitazone administered for 8 and 12 weeks. Troglitazone administration significantly improved insulin resistance, but did not affect pancreatic beta-cell function as evaluated by the homeostasis model assessment (HOMA). In the present study, we reported for the first time that troglitazone administration significantly reduces plasma levels of TNF-alpha in obese patients with type 2 diabetes.

A 39-year-old woman with hyperglycemia and ketonuria but with normal HbA1c level was diagnosed as having fulminant type 1 diabetes. The patient had 8-fold increase in the plasma titer of coxsackie B4 virus neutralizing antibody. Infection with coxsackie B4 virus was associated with fulminant type 1 diabetes.

SummaryThe activity of plasmin plays a critical role in the development of chronic glomerulonephritis. Thrombin-activatable fibrinolysis inhibitor (TAFI) is a potent inhibitor of plasmin generation. We hypothesized thatTAFI is involved in the pathogenesis of glomerulonephritis because it inhibits plasmin generation. To demonstrate this hypothesis, we compared the development of immune complex-mediated glomerulonephritis in wild-type and TAFI-deficient mice. After six weeks of treatment with horse spleen apoferritin and lipoplysaccharide to induce glomerulonephritis, mice deficient in TAFI had significantly better renal function as shown by lower concentrations of albumin in urine and blood urea nitrogen compared to wild-type mice. In addition, the activity of plasmin and matrix metalloproteinases was significantly increased, and mesangial matrix expansion and the deposition of collagen and fibrin in kidney tissues were significantly decreased in TAFI-knockout mice as compared to their wildtype counterparts. Depletion of fibrinogen by batroxobin (Defibrase) treatment led to equalization of the renal function and the amount of collagen deposition in the kidneys of TAFI-knockout and wild-type mice with immune complex-mediated glomerulonephritis. Together these observations suggest that TAFI-mediated inhibition of plasmin generation plays a role in the pathogenesis of glomerulonephritis, and that it may constitute a novel molecular target for the therapy of this disease.

Background: Oxidative stress plays an important role in the pathogenesis of chronic liver diseases. The plasma level of 8-isoprostane, a product of lipid peroxidation, is a marker of oxidative stress in vivo. The aim of the present study was to clarify whether the degree of lipid peroxidation, as measured by the plasma level of 8-isoprostane, influences the progression of chronic liver diseases and hepatocarcinogenesis. Methods: Plasma 8-isoprostane levels were investigated in 14 patients with non-alcoholic fatty liver disease (NAFLD), 75 with chronic hepatitis C (CH-C), 14 with cured CH-C, 14 with HCV-positive hepatocellular carcinoma (HCC-C) and 38 healthy volunteers. 8-Isoprostane was measured by enzyme immunoassay after affinity column purification. Results: Plasma 8-isoprostatne was significantly elevated in NAFLD (11.9 [3.8–56.8] pg/mL), CH-C (10.1 [4.2–134.5] pg/mL) as compared to controls (6.3 [3.6–11.1] pg/mL). Plasma 8-isoprostane values were positively correlated with body mass index in NAFLD (P

Objective: To investigate the relationship between active ghrelin and oxidative stress in obese subjects. Design: We measured the plasma levels of free 8-epi-prostaglandin F2α (8-epi-PGF2α, a reliable and systemic marker of oxidative stress) and the active form of ghrelin in 17 obese and 17 normal subjects. The biologically active forms of ghrelin were measured using a commercially available radio-immunoassay kit and free 8-epi-PGF2α was measured using an enzyme immunoassay kit. Results: The circulating level of active ghrelin was significantly decreased (20.4 ± 2.6 vs 40.9 ± 3.9 fmol/ml, P < 0.01) while that of 8-epi-PGF2α was significantly increased (61.5 ± 9.6 vs 17.3 ± 3.4 pg/ml, P < 0.01) in obese subjects compared with normal subjects. The plasma levels of active ghrelin and 8-epi-PGF2α were significantly correlated in obese (r = −0.507, P < 0.05) and in all (r = −0.577, P < 0.01) subjects. Multivariate analysis showed that the plasma levels of active ghrelin and 8-epi-PGF2α were significantly and independently correlated in all subjects (F = 7.888, P < 0.01). Conclusions: There is an inverse correlation between circulating levels of active ghrelin and oxidative stress in obesity. Low circulating levels of active ghrelin may enhance oxidative stress and the process of atherosclerosis in obese subjects.

Hepatic lipase (HL) is synthesized in the liver and hydrolyses triglyceride and phospholipids. C-514T polymorphism in HL gene promoter was reported to associate with hepatic lipase activity and plasma lipid levels. We examined whether C-514T polymorphism affects glucose metabolism beyond its effect on plasma lipid levels in nondiabetic Japanese subjects. Gene frequencies of C/C homozygote, C/T heterozygote and T/T homozygote were 18, 51 and 31%, respectively. The allelic frequencies of C and T were 44 and 56%, respectively. T allele frequency was much higher than in Caucasian subjects. Moreover, -514T allele carriers had higher levels of triglyceride (P=0.027), fasting insulin (P=0.016) and HOMA-IR (P=0.033) than non-carriers. In contrast to some former studies, -514T allele affected triglyceride levels and insulin sensitivity. Taken together, HL gene might be one of the important susceptibility genes of type 2 diabetes and the high incidence of type 2 diabetes could be explained by high frequency of -514T allele in the Japanese population. Moreover, since HL and adiponectin showed an additive effect on insulin sensitivity, these genetic variations can be independently associated with insulin sensitivity.

To investigate the relationship between oxidative stress and circulating levels of adiponectin in Japanese metabolically obese, normal-weight [MONW; BMI25 and visceral fat area; VFAor =100 cm2 by abdominal computed tomography (CT) scanning] men with normal glucose tolerance (NGT), we measured the plasma levels of free 8-epi-prostaglandin F2alpha (8-epi-PGF2alpha) and adiponectin in 28 MONW and 23 normal men. The plasma levels of free 8-epi-PGF2alpha were measured using a commercially available enzyme immunoassay (EIA) kit (Cayman Chemical, Ann Arbor, MI). The plasma levels of adiponectin were measured using a radioimmunoassay kit (LINCO Research, St. Charles, MO). Plasma levels of 8-epi-PGF2alpha in MONW subjects (30.4+/-4.0 pg/ml; P0.01) were significantly increased compared to controls (8.1+/-1.3 pg/ml). The plasma levels of adiponectin were significantly decreased in MONW subjects (8.6+/-0.9 microg/ml; P0.01) as compared to normal subjects (11.6+/-0.6 microg/ml). The plasma levels of 8-epi-PGF2alpha and adiponectin were significantly correlated in MONW (r=-0.617, P0.01) and in all (MONW+normal) (r=-0.620, P0.01) subjects. The plasma levels of 8-epi-PGF2alpha and adiponectin were significantly correlated after adjustment for VFA in MONW subjects (F=11.042, P0.01). The present study showed that systemic increase in oxidative stress correlates with decreased circulating levels of adiponectin in Japanese MONW men with NGT. Although correlation does not prove causation, this observation suggests that increased oxidative stress may decrease the production of adiponectin in Japanese MONW men with NGT.

To clarify whether quantitative insulin sensitivity check index (QUICKI) is useful as an indicator of insulin resistance in Japanese metabolically obese, normal-weight (MONW, body mass index (BMI)

Metformin is thought to decrease blood glucose levels by reducing hepatic glucose output. To elucidate the pharmacological action of metformin on hepatic glucose production, we examined its effect on the gene expression of glucose-6-phosphatase (G6Pase), a key enzyme of gluconeogenesis, in H4IIE rat hepatoma cell line by RT-PCR and quantitative real-time PCR. Metformin suppressed dexamethasone/cAMP-induced expression of G6Pase mRNA in a dose dependent manner, its maximum effect being observed at 2 mM (79.3% inhibition, P

Thrombin-activable fibrinolysis inhibitor (TAFI) is a key modulator of fibrinolysis. We have reported the elevated levels of plasma TAFI and their correlation with visceral fat area and insulin resistance in the patients with type 2 diabetes. Furthermore, the expression of TAFI was demonstrated in adipose tissues. Thus, we hypothesized that TAFI secreted from adipose tissues might be an important causative factor of hypofibrinolysis in patients with insulin resistance and that insulin was a modulator of the gene expression of TAFI. To evaluate this hypothesis, we examined the regulation of TAFI expression by insulin in adipocytes. TAFI mRNA was induced dose-dependently by insulin in 3T3-L1 adipocytes. PI3 kinase inhibitor wortmannin inhibited insulin-induced expression, but MEK1 inhibitor PD98059 had no effects. These data suggested that the gene expression of TAFI was regulated by PI3 kinase signaling pathway. Moreover, activated Akt induced the expression of TAFI mRNA to a similar extent by insulin in 3T3-L1 adipocytes expressing tamoxifen-regulatable Akt. In conclusion, TAFI was induced by insulin through PI3 kinase/Akt pathway in adipocytes. It is supposed that plasma TAFI levels are regulated at least in part by transcription levels in adipose tissues of patients with insulin resistance.

Adiponectin is an adipocyte-secreted protein that is known to modulate insulin sensitivity and glucose homeostasis. A number of genetic variations have been studied. Among them, two single-nucleotide polymorphisms (SNP45T>G, SNP276G>T) showed an association with type 2 diabetes in the Japanese population. In this study, we examined the association between these SNPs and risk factors of type 2 diabetes in 194 non-diabetic Japanese subjects. SNP45 was associated with insulin sensitivity (determined by HOMA-IR, p=0.046) and obesity (body mass index; BMI, p=0.043). SNP276 showed a stronger association with HOMA-IR (p=0.018) and BMI (p=0.017). However, neither SNP had an association with insulin secretion (insulinogenic index) and plasma lipid levels. Moreover, a linkage dis-equilibrium was observed between SNP45 and SNP276. Carriers with SNP45G-SNP276G haplotype had higher BMI (p=0.034) and carriers with SNP45T-SNP276T haplotype had lower BMI (p=0.005) and HOMA-IR (p=0.037). Adiponectin gene variations showed an association with obesity and insulin sensitivity, and adiponectin genotypes may predict the increasing risk for type 2 diabetes in non-diabetic subjects.

OBJECTIVE: To investigate the relationship between the circulating level of active ghrelin and abdominal adiposity, serum levels of insulin or insulin resistance in patients with type 2 diabetes mellitus. DESIGN: We measured the plasma levels of the active form of ghrelin in 18 obese and 18 nonobese patients with type 2 diabetes mellitus using a radioimmunoassay (RIA) kit. Body fat accumulation was measured by computed tomography (CT) and insulin resistance by the glucose infusion rate (GIR) during an euglycemic hyperinsulinemic clamp study. RESULTS: Plasma levels of ghrelin in obese patients with type 2 diabetes mellitus were significantly decreased compared with nonobese patients. There were significant correlations between the plasma levels of ghrelin and BMI (r=-0.505, P

OBJECTIVE: It is well known that nitric oxide synthase (NOS) is expressed and that it modulates glucose transport in skeletal muscles. Recent studies have shown that adipose tIssues also express inducible and endothelial nitric oxide synthase (eNOS). In the present study, we investigated whether nitric oxide (NO) induces glucose uptake in adipocytes, and the signaling pathway involved in the NO-stimulated glucose uptake in 3T3-L1 adipocytes. METHODS: First, we determined the expression of eNOS in 3T3-L1 adipocytes, and then these cells were treated with the NO donor sodium nitroprusside (SNP) and/or insulin, and glucose uptake and phosphorylation of insulin receptor substrate (IRS)-1 and Akt were evaluated. Moreover, we examined the effects of a NO scavenger, a guanylate cyclase inhibitor or dexamethasone on SNP-stimulated glucose uptake and GLUT4 translocation. RESULTS: SNP at a concentration of 50 mmol/l increased 2-deoxyglucose uptake (1.8-fold) without phosphorylation of IRS-1 and Akt. Treatment with the NO scavenger or guanylate cyclase inhibitor decreased SNP-stimulated glucose uptake to the basal level. Dexamethasone reduced both insulin- and SNP-stimulated glucose uptake with impairment of GLUT4 translocation. CONCLUSION: NO is capable of stimulating glucose transport through GLUT4 translocation in 3T3-L1 adipocytes, via a mechanism different from the insulin signaling pathway.

Previous studies have demonstrated that oxidative stress is associated not only with hyperglycemia and hypertension but also with the metabolic syndrome and cadiovascular disease (1–3). Adrenomedullin (AM) is a novel vasorelaxant peptide isolated from human pheochromocytoma (4,5). Oxidative stress enhances AM production from endothelium and vascular smooth muscle cells in vitro (6,7). However, whether oxidative stress is associated with circulating levels of AM in vivo is unknown. In the present study, we evaluated the relationship between the plasma levels of 8-epi-prostaglandinF2α (8-epi-PGF2α; currently regarded as the most reliable marker for the assessment of oxidative stress in humans) (8,9) and AM in normal subjects and hypertensive patients with type 2 diabetes. This study comprised 17 hypertensive patients with type 2 diabetes (15 men and 2 women, age 47.3 ± 3.0 years [mean ± SE], BMI 23.2 ± 0.8 kg/m2, fasting plasma glucose 8.2 ± 0.5 mmol/l, HbA1c 9.9 ± 0.5%, fasting serum insulin 30.6 ± 3.0 …

OBJECTIVE: To investigate the effect of acute hyperinsulinemia on the plasma levels of adrenomedullin (AM) in patients with type 2 diabetes mellitus. DESIGN: We measured the plasma levels of AM in 18 patients with type 2 diabetes mellitus and in 19 normal subjects before and during a euglycemic hyperinsulinemic clamp study (the goal was for blood sugar levels of 5.24 mmol/l and insulin levels of 1200 pmol/l). Both plasma AM and serum insulin were measured by immunoradiometric assays. RESULTS: Before the glucose clamp study there was no significant difference in the plasma levels of AM between patients with type 2 diabetes mellitus and normal subjects. During the glucose clamp study, the serum levels of insulin significantly increased (from 33.0+/-3.6 to 1344.6+/-67.8 pmol/ml, P

The patient was a 32-year-old obese woman with a history of type 2 diabetes and hypertension for 6 years. Although she was treated with antihypertensive agents and intensive insulin therapy, her hyperglycemia was difficult to control. She wanted to have a baby but pregnancy was not recommended because her diabetes was under poor control and the use of antihypertensive medication. To achieve good control of obesity, diabetes and hypertension, she was admitted to our clinical department for weight reduction using very low calorie diet (VLCD). During VLCD she had a 19.8 kg reduction in body weight and her blood glucose and blood pressure were in good control without the use of drugs. Five months later, she became pregnant after the fourth trial of intrauterine insemination (IUI) and gave birth to a female baby under insulin therapy. This is the first report that showed the usefulness of VLCD for prepregnant control of glucose metabolism and blood pressure in an obese hypertensive patient with type 2 diabetes mellitus.

We investigated the relationship of codon 972 polymorphism of the insulin receptor substrate-1 (IRS-1) gene with insulin resistance in the Japanese population. Among 130 patients with type-2 diabetes mellitus (DM), we identified 6 who were heterozygous for the Gly972Arg mutation. Among 144 healthy subjects, 6 were heterozygous and 1 was homozygous for the mutation. A hyperinsulinemic euglycemic clamp study was performed in 3 of 6 diabetic patients with the heterozygous Gly972Arg mutation and in 60 without it. Both groups showed almost the same levels of insulin sensitivity (glucose infusion rate, GIR = 50.2 ± 3.0 vs. 51.3 ± 12.1 μmol/kg/min). Similarly, there was no difference in insulin sensitivity between healthy subjects with and without the mutation using the homeostasis model assessment (HOMA index = 1.14 ± 0.50 vs. 1.02 ± 0.63). The frequency of the Gly972Arg allele was not increased in diabetic patients compared with control subjects even in aged (>50 years old) or obese (BMI ≥25) subjects. Among healthy subjects, we identified a 25-year-old male with the homozygous Gly972Arg allele. He was slightly obese (BMI = 25.5) but showed relatively high insulin sensitivity, almost equal to that of healthy subjects without the mutation (GIR = 67.2 vs. 71.8 ± 22.0 μmol/kg/min). Because the GIR in healthy subjects was significantly higher compared with that in type-2 DM patients, we speculate that another genetic or environmental factor producing a more deleterious effect on insulin sensitivity may exist in diabetic patients. We conclude that this gene abnormality does not play a role in the pathogenesis of insulin resistance and type-2 DM.

A 39-year-old man with chief complaints of aphasia, disorientation and acalculia was admitted to our hospital. He was diagnosed as a clinically probable case of multiple sclerosis (MS) and his symptoms improved while on steroid pulse therapy. The patient had been diagnosed as having diabetes mellitus 16 years before the onset of MS and his insulin secretion further decreased with time. Slight insulin resistance was observed during a euglycemic hyperinsulinemic clamp study. These results suggested that this patient developed diabetes mellitus mainly due to the decrease of insulin secretion.