Impaired glucose tolerance is a risk factor for stroke in a Japanese sample--the Funagata study.

Impaired glucose tolerance (IGT) is a known risk factor for cardiovascular disease, which includes stroke as well as coronary heart disease (CHD). We investigated whether IGT is a risk factor for stroke. The incidence of stroke and CHD in a cohort population (n = 2938) consisting of participants of the 1990-1997 Funagata study was assessed through interviews with the participants and their family members and reviews of death certificates and residence transfer documents through 2002. Glucose tolerance at the baseline was classified according to the criteria of the 1998 World Health Organization (normal glucose tolerance, n = 2189; IGT, n = 320; and diabetes, n = 286). The cumulative incidences among the groups were compared using the Kaplan-Meier product-limit method, and the risks of these conditions were evaluated by person-year and Cox proportional hazard methods. During the 147-month (mean, 116.5 months) follow-up, 158 (normal glucose tolerance, IGT, and diabetes: 94, 35, and 29, respectively) participants experienced a stroke and 94 (54, 16, and 24, respectively) experienced CHD. By the person-year method, IGT and diabetes were shown to be significant risk factors for stroke and CHD (odds ratio, 1.87 [95% confidence interval, 1.73-2.03] and 3.57 [3.21-3.98] for stroke; 1.53 [1.31-1.78] and 3.47 [2.91-4.14] for CHD, respectively). Cox proportional hazard analysis showed that IGT was a risk factor for stroke (age-, sex-, and hypertension-adjusted hazard ratio: 1.51 [95% confidence interval, 1.02-2.24], P = .039) but not for CHD (1.21 [0.69-2.313], .509). Impaired glucose tolerance is a risk factor for future stroke in a Japanese population.

Ghrelin infused into the portal vein inhibits glucose-stimulated insulin secretion in Wistar rats.

Although accumulating evidence has shown crucial roles of ghrelin and insulin in food intake and energy metabolism, the exact relationship between these hormones remains unclear. In this study, we determined the in vivo effect of ghrelin on insulin secretion. We demonstrated that ghrelin inhibited the glucose-stimulated release of insulin when infused into the portal vein of Wistar rats. However, ghrelin infusion into the femoral vein did not induce such an inhibitory effect. Hepatic vagotomy or coinfusion with atropine methyl bromide diminished the inhibitory effect of ghrelin on glucose-stimulated insulin secretion. In conclusion, ghrelin exerts an inhibitory effect on glucose-stimulated insulin secretion via the hepatic portal system and the vagus nerve. The decrease in ghrelin level after a meal is important for the occurrence of the incretin effect in rats.

Correlation between change in body weight rather than current body weight and change in serum adiponectin levels in a Japanese population -- the Funagata study.

Serum adiponectin levels are decreased in obese subjects. We examined the association of current body weight (BW) and its change with a change in serum adiponectin levels. Serum adiponectin levels at the baseline (from 1995 to 1997) and the 5-year follow-up (from 2000 to 2002) examinations were evaluated in 1003 (M/F, 425/578; age at the baseline examinations, 58.3 +/- 11.7/57.5 +/- 11.0 years) Japanese subjects from a cohort population (N = 2013) of the Funagata study. Correlations and associations of BW at the baseline examinations and changes in BW between the baseline and the follow-up examinations (deltaBW) with changes in the serum adiponectin levels in the study period (deltaAdiponectin) were examined. Stepwise regression analyses revealed a significant correlation of the deltaBW (r = -0.233 and -0.204 for men and women, respectively; r = -0.324 for the upper tertile group divided based on their body mass index in women) with the deltaAdiponectin. However, the BW at the baseline examinations was not significantly correlated in both sexes. Multiple logistic regression analyses revealed that subjects who reduced their BW by 2 kg or more were 2.56 (95% confidence interval, 1.21-5.42; P = .014) and 8.24 times (95% confidence interval, 3.59-18.9; P < .001) more likely to be in the upper tertile of the deltaAdiponectin than those who increased their BW by 2 kg or more in men and women, respectively, independent of their BW at the baseline examinations. In conclusion, we showed here that the deltaBW was strongly associated with the deltaAdiponectin in both sexes, whereas the BW at the baseline examinations was not associated with the deltaAdiponectin, at least in women.

Association of decrease in serum dehydroepiandrosterone sulfate levels with the progression to type 2 diabetes in men of a Japanese population: the Funagata Study.

Association of serum dehydroepiandrosterone sulfate (DHEAS) levels with insulin resistance and impairment of insulin secretion have been reported. We here examined the association of serum DHEAS levels with type 2 diabetes mellitus (DM) and the progression to DM. The serum DHEAS levels at baseline (from 1995 to 1997) were evaluated in 1709 individuals (998 women and 711 men) from a cohort population (n = 3706) of the Funagata Study. Glucose tolerance was evaluated at baseline as well as at 5-year follow-up examinations (n = 970, follow-up rate, 56.8%) according to the 1985 World Health Organization criteria. The statistical significance of the difference between any 2 groups was determined by the Student t test. Multiple logistic regression analysis determined the association of the traits with the progression to DM at the 5-year follow-up examinations. P < .05 was accepted as statistically significant. The serum DHEAS levels were significantly lower in DM than in normal glucose tolerance. However, this difference was not significant when adjusted for age. In men, the decrease in serum DHEAS levels by the 5-year follow-up examinations was significantly larger in the subjects who became diabetic than in the subjects who remained normal glucose tolerance, even when adjusted for age ( P = .0003). Multiple logistic regression analysis revealed a significant association of the decrease in serum DHEAS levels with the progression to DM, with an odds ratio (per 0.1 log ng/mL) of 1.410 (95% confidence interval [CI], 1.020-1.948, P = .038), independently from age, height, and 2-hour plasma glucose in men. A decrease in serum DHEAS levels seems to be associated with the progression to DM in Japanese men.

Insulin inhibits glucagon-induced glycogenolysis normally in perivenous hepatocytes of Wistar fatty rats.

Wistar fatty (WF) rats are obese, hyperinsulinemic and hyperglycemic, and thus a model of type 2 diabetes mellitus. Since we have found that insulin specifically inhibits glucagon-induced glycogenolysis in perivenous hepatocytes (PVH) from normal rats, we examined the inhibitory effect of insulin on glucagon-induced glycogenolysis in PVH of hyperinsulinemic WF rats. Basal glucose release was 64.0+/-4.1 nmol/mgprotein/30 min from PVH of lean littermates (WL rats) and 137.0+/-19.3 nmol/mgprotein/30 min from that of WF rats (p<0.01). These were proportional to the glycogen content in PVH of WL and WF rats (56.7+/-7.2 and 131.0+/-20.3 microg/mgprotein, p<0.01), and increased to 109.0+/-8.8 and 225.8+/-17.9nmol/mgprotein/30min, respectively, with 0.1 nmol/l glucagon. When 10 nmol/l insulin was coincubated, 0.1 nmol/l glucagon-induced increase in glucose release decreased to 93.3+/-10.9 nmol/mgprotein/30 min in PVH of WL rats (p<0.01) and to 181+/-20.7 nmol/mgprotein/30 min in PVH of WF rats (p<0.01). Thus, insulin antagonized glucagon-induced glycogenolysis in PVH similarly between WL and WF rats, to 56.7+/-13.3% and to 46.1+/-7.5%, respectively. Thus, the antagonizing effect of insulin on glucagon-induced increase in glycogenolysis was preserved in PVH of hyperinsulinemic and hyperglycemic WF rats.

Decreased serum levels of adiponectin are a risk factor for the progression to type 2 diabetes in the Japanese Population: the Funagata study.

OBJECTIVE: To examine whether decreased serum levels of adiponectin are an independent risk factor for the progression to type 2 diabetes in a Japanese population. RESEARCH DESIGN AND METHODS: The serum levels of adiponectin and tumor necrosis factor-alpha (TNF-alpha) at baseline (from 1995 to 1997) were evaluated in 1,792 individuals (1,023 women and 769 men, aged 58.5 +/- 12.5 years) from a cohort population (n = 3,706) of the Funagata study. Glucose tolerance was evaluated at baseline and also at 5-year follow-up examinations (n = 978, follow-up rate, 54.6%) according to the 1985 World Health Organization criteria. The correlation of clinical traits with serum levels of adiponectin was examined. The association of the traits with the progression to type 2 diabetes at the 5-year follow-up was also examined. RESULTS: Among the traits examined, the correlation with aging was highest (r = 0.312, P < 0.001). Eighteen subjects with normal glucose tolerance (NGT) developed diabetes, and 709 remained NGT at the 5-year follow-up examinations. The subjects who became diabetic had decreased serum levels of adiponectin (7.29 +/- 2.35 vs. 9.13 +/- 2.35 10 x log microg/ml, P = 0.009). Multiple logistic regression analysis with age, sex, waist-to-hip ratio, and 2-h plasma glucose as the variables revealed that serum adiponectin level (odds ratio [per 0.1 log microg/ml] 0.766, P = 0.029) was an independent risk factor for the progression to type 2 diabetes. The subjects whose serum levels of adiponectin were in the lowest tertile were 9.320 times (95% CI 1.046-83.1) more likely to develop diabetes than those in the highest tertile (P = 0.046). CONCLUSIONS: Decreased serum adiponectin level is an independent risk factor for progression to type 2 diabetes.

Glucagon-like peptide-1 inhibits glucagon-induced glycogenolysis in perivenous hepatocytes specifically.

Hepatocytes form the hepatic acinus as a unit of microcirculation. Following the bloodstream, at least two different zones can be discerned: the periportal (PPH) and the perivenous (PVH) zones. Recently, we found that insulin inhibits glucagon-induced glycogenolysis in PVH specifically. We therefore investigated the region-specific functional effects of glucagon-like peptide-1 (GLP-1), which is known to have an insulin-like activity, on glucagon-induced glycogenolysis in isolated PPH and PVH prepared by the digitonin-collagenase method. GLP-1 inhibited 0.1 nM glucagon-induced increase in glucose release from the PVH of fed rats specifically (p < 0.01) and had an additive effect with insulin. Insulin binding did not differ between PPH and PVH of fed rats. GLP-1 did not displace [125I]-glucagon binding to the purified hepatic cell membrane. Thus, it is directly confirmed that GLP-1 has an insulin-like activity in the liver.

Clinical utility and approach to estimate postprandial hypertriglycemia by a newly designed oral fat-loading test.

The objective of this study was to estimate postprandial hypertriglycemia by a newly designed oral fat-loading test. Twenty-three healthy normolipidemic volunteers were orally administered a test meal consisting of a mixture of Telmeal 2.0 and 20 g of salt-free butter after fasting for 12 h. To measure the levels of total cholesterol (T-Cho), triglycerides (TG), high-density lipoprotein-cholesterol (HDL-C), remnant-like particle-cholesterol (RLP-C), lipoprotein (a) [Lp (a)], free fatty acid, apolipoproteins (Apos), plasma glucose (PG), immunoreactive insulin (IRI), and high-sensitivity C-reactive protein (hs-CRP), venous blood samples were collected before the meal and at each hour until 9 h after fat-loading. The levels of both TG and RLP-C were drastically elevated at 2 h after fat-loading and these levels remained high until 4 h (p < 0.01). A significant correlation between TG and RLP-C was also observed at 2, 3 and 4 h, and the values of the correlation coefficients (r) were 0.837, 0.838, and 0.908, respectively. In contrast, the levels of T-Cho, HDL-C, Lp (a), Apos, PG, and hs-CRP did not change. Furthermore, there were no gastrointestinal symptoms during or after the study. These results strongly suggested that this newly designed fat-loading test was very useful for evaluating postprandial hypertriglycemia, including remnant concentrations.

Calpain 10 gene polymorphisms are related, not to type 2 diabetes, but to increased serum cholesterol in Japanese.

A G-to-A (UCSNP-43) polymorphism of the calpain-10 gene was significantly associated with type 2 diabetes (DM) in Mexican-American, and was postulated, together with a T-to-C (UCSNP-44) polymorphism, as a risk factor for DM. We examined the association of these genotypes with DM in Japanese. Eighty-one subjects with DM and 81 non-diabetic subjects (NGT) were recruited. The number of subjects with genotypes UCSNP-43 G/G, G/A and A/A were 76, 5 and 0, respectively, for the DM and NGT groups. The number of subjects with genotypes UCSNP-44 T/T, T/C and C/C were 66, 14 and 1 for the DM group and 64, 17 and 0 for the NGT group. There was no difference between the groups in terms of frequency of any genotype combinations. No association between the genotypes and DM was observed. We next examined the differences between the genotypes or genotype combinations in terms of the traits related to DM, obesity, hypertension and dyslipidemia. No differences were observed between the genotypes UCSNP43 G/G and G/A, between UCSNP-44 T/T and the others, or between the genotype combination UCSNP-43 G/G and UCSNP-44 T/T and the others, except that the individuals with the genotype combination had significantly increased serum cholesterol levels (212.6 +/- 34.3 vs. 198.5 +/- 29.9, P=0.020). The genotype combination might be a risk factor, not for DM, obesity and hypertension, but for increased serum cholesterol.

A palatinose-based balanced formula improves glucose tolerance, serum free fatty acid levels and body fat composition.

Palatinose is a disaccharide present in honey, which has the characteristics of delayed digestion and absorption. We developed a palatinose-based balanced formula (PBF) and reported its beneficial effects on metabolic syndrome-related parameters in rats. To examine the effects of PBF in humans, we here conducted a crossover study using twenty-three subjects with impaired glucose tolerance. The subjects were divided into two groups: intervention to control (I/C) and control to intervention (C/I) groups. The I/C group consumed PBF (250 kcal) together with foods that were 250 kcal less than their usual breakfast (intervention meal) for the first 12 weeks, followed by their usual breakfast (control meal) for the last 12 weeks. The protocol for the C/I group was opposite in order: the control meal for the first 12 weeks, followed by the intervention meal for the last 12 weeks. In the first 12-week period, the intervention meal decreased 2-hr plasma glucose levels after 75-g oral glucose tolerance test (-15.7 +/- 20.1% change), while the control meal did not (0.8 +/- 31.6% change). The difference between these changes was significant (p = 0.038). The similar results were obtained from the comparison of the changes between the first and the last 12-week periods in the two groups combined (intervention vs control: -11.8 +/- 22.5 vs 11.2 +/- 30.2% change, p = 0.024). PBF also had the beneficial effects on serum free fatty acids levels and visceral fat area. In conclusion, PBF consumption has beneficial effects on metabolic syndrome-related parameters in humans.

Association of the ABCA1 gene polymorphisms with type 2 DM in a Japanese population.

To examine the association of the ATP-binding cassette transporter 1 (ABCA1) gene with type 2 diabetes (DM), we studied genetic polymorphisms of the ABCA1 gene including its linkage disequilibrium (LD) and haplotype analyses using a Japanese population. A sample set (DM:72, IGT:75, and NGT:227) was genotyped with 34 SNPs distributed from the promoter region to the last exon of the ABCA1 gene. LD between SNPs was assessed in pairwise manner. Among 13 LD blocks constructed, an LD block at the 5'-region showed a significant difference in the haplotype distribution between the study groups (NGT vs. IGT + DM: overall p = 0.0180; NGT vs. DM: 0.0001). Fisher's exact probability test (NGT vs. DM) showed a significant association of the haplotype 2 of the LD block (p = 0.0001), with an odds ratio (OR) of 2.53 (95%CI:1.62-4.12). Diplotype analysis also showed a significant association of the diplotypes with the haplotype 2 (OR:2.59, 95%CI:1.48-4.54, p = 0.0013).

Mechanisms of inhibitory effects of cerivastatin on rat vascular smooth muscle cell growth.

The aim of this study was to clarify the mechanism(s) of an inhibitory effect of cerivastatin on cultured rat vascular smooth muscle cell (VSMC) growth. After being starved, cultured VSMCs were stimulated by 5% fetal bovine serum with either various concentrations of cerivastatin or 10-4 M of mevalonate. Cerivastatin dose-dependently decreased the values of [3H]-thymidine incorporation and cell numbers and the level of phosphorylated extracellular signal-regulated protein kinase 1/2. It also suppressed the level of proliferative cell nuclear antigen in a dose-dependent manner. These reductions were abolished by the addition of mevalonate. Similarly, the level of phosphorylated p38 was also decreased by cerivastatin. In contrast, cerivastatin dose-dependently activated the phosphorylation of both c-jun NH2-terminal protein kinase and activating transcription factor-2, and these activations were abolished by the addition of mevalonate. The levels of phosphorylated Akt and p70 S6 kinase as well as those of Bcl-2 were dose-dependently reduced by cerivastatin, and these reductions were abolished by the addition of mevalonate. Cerivastatin could dose-dependently elevate the levels of CPP32/caspase-3 activity and cytoplasmic histone-associated DNA fragments in VSMCs without causing cytotoxicity. These results indicate that cerivastatin suppresses cell survival and activates the apoptotic cellular signaling in VSMCs, suggesting that it could be effective for preventing the progression of restenosis after angioplasty.

Increased urinary levels of pentosidine, pyrraline and acrolein adduct in type 2 diabetes.

This study investigates whether urinary levels of pentosidine, pyrraline and acrolein adduct are increased in type 2 diabetes (DM), and whether these levels are correlated with glycemic control and clinical traits. Urinary levels of pentosidine, pyrraline and acrolein adduct in DM patients (n = 100) recruited from the outpatient clinic of our university hospital were compared with those of age- and sex-matched non-diabetic subjects (n = 50). The correlation of these urinary levels with the glycemic control and the clinical traits were examined. Furthermore, the influence of smoking habit on the levels of acrolein adduct was examined. Urinary levels of pentosidine, pyrraline and acrolein adduct were all significantly (p<0.001) higher in the DM group than in the non-DM group (pentosidine (log(pmol/mgCr)), 1.579 +/- 0.147 vs 1.427 +/- 0.142; pyrraline (log(nmol/mgCr)), 0.888 +/- 0.402 vs 0.581 +/- 0.336; acrolein adduct (log(nmol/mgCr)), 2.316 +/- 0.221 vs 2.051 +/- 0.201). Glycemic control parameters, such as fasting plasma glucose (FPG) and HbA1c, were significantly correlated with these urinary levels. Age was correlated with the urinary levels of pentosidine but not with those of pyrraline and acrolein adduct. The urinary albumin excretion rate did not correlate with any of these urinary levels. The levels of acrolein adduct were higher in the subjects with smoking habit than in those without the habit in the DM group as well as in the non-DM group (DM, 2.391 +/- 0.230 and 2.212 +/- 0.190, p=0.0004; Non-DM, 2.120 +/- 0.171 and 1.993 +/- 0.206, p=0.0503). The urinary levels of pentosidine, pyrraline and acrolein adduct were increased in DM and were significantly correlated with glycemic control levels. In addition, smoking habit seems to increase the urinary levels of acrolein adduct.

The D allele of the angiotensin-converting enzyme insertion/ deletion (I/D) polymorphism is a risk factor for type 2 diabetes in a population-based Japanese sample.

The association of the ACE gene I/D polymorphism with type 2 diabetes (DM) was examined in a population-based Japanese sample. A total of 902 individuals (490 females and 412 males, age 58.8 +/- 12.2 yr) from a cohort population (n = 3,706) of the Funagata diabetes study were divided into three groups according to genotype: D/D (n = 104), I/D (n = 436) and I/I (n = 362). Chi-square test and ANOVA were used for association studies and to assess the differences in the traits' values, respectively. More individuals with the genotypes D/D and I/D were diabetic (8.7% and 4.1%, respectively) than those with the genotype I/I (2.8%, p = 0.008 and p = 0.032, respectively). The genotype D/D was a risk factor for DM (relative risk (RR) 3.13, 95% CI 1.31-7.51), and also for DM and IGT (RR 1.78, 95% CI 14-2.76). Multiple logistic regression analysis also showed that the genotypes with the D allele were risk factors for DM and IGT even when adjusting for age, sex, hypertension and serum total cholesterol levels (odds ratio 1.49, 95% CI 1.01-2.21). The D allele of the ACE gene I/D polymorphism is a risk factor for DM.

Progression of diabetic nephropathy enhances the plasma osteopontin level in type 2 diabetic patients.

Osteopontin (OPN) is thought to play multiple roles in the progression of atherosclerotic plaque including diabetic vascular complications. However, it still remains unclear whether the level of OPN in vivo is indeed clinically associated with the progression of diabetic complications. This study evaluated whether the levels of OPN in plasma and urine are correlated with the progression of diabetic complications, such as retinopathy, neuropathy, and nephropathy in patients with type 2 diabetes. In 229 patients with type 2 diabetes, OPN level in plasma and urine was evaluated by both the severity of diabetic complications, such as retinopathy, neuropathy, and nephropathy, and the clinical characteristics and the substantial laboratory findings. Plasma OPN level increased significantly with aging and the progression of diabetic nephropathy, especially at the stage of renal failure (p<0.05). However, the level was not related to the progression of retinopathy or neuropathy, or to laboratory findings, such as HbA1c or serum lipids. In contrast, urinary OPN level was not associated with diabetic complications in any of the subjects. There was no correlation between the plasma and urinary values of OPN. The results established that the plasma OPN was elevated in proportion to the progression of diabetic nephropathy, indicating that the plasma concentration may be a potential diagnostic predictor of diabetic end-stage renal disease.