Mai Asano

Supplementation of hydrogen-rich water improves lipid and glucose metabolism in patients with type 2 diabetes or impaired glucose tolerance.

Oxidative stress is recognized widely as being associated with various disorders including diabetes, hypertension, and atherosclerosis. It is well established that hydrogen has a reducing action. We therefore investigated the effects of hydrogen-rich water intake on lipid and glucose metabolism in patients with either type 2 diabetes mellitus (T2DM) or impaired glucose tolerance (IGT). We performed a randomized, double-blind, placebo-controlled, crossover study in 30 patients with T2DM controlled by diet and exercise therapy and 6 patients with IGT. The patients consumed either 900 mL/d of hydrogen-rich pure water or 900 mL of placebo pure water for 8 weeks, with a 12-week washout period. Several biomarkers of oxidative stress, insulin resistance, and glucose metabolism, assessed by an oral glucose tolerance test, were evaluated at baseline and at 8 weeks. Intake of hydrogen-rich water was associated with significant decreases in the levels of modified low-density lipoprotein (LDL) cholesterol (ie, modifications that increase the net negative charge of LDL), small dense LDL, and urinary 8-isoprostanes by 15.5% (P < .01), 5.7% (P < .05), and 6.6% (P < .05), respectively. Hydrogen-rich water intake was also associated with a trend of decreased serum concentrations of oxidized LDL and free fatty acids, and increased plasma levels of adiponectin and extracellular-superoxide dismutase. In 4 of 6 patients with IGT, intake of hydrogen-rich water normalized the oral glucose tolerance test. In conclusion, these results suggest that supplementation with hydrogen-rich water may have a beneficial role in prevention of T2DM and insulin resistance.

Relationship between serum bilirubin and albuminuria in patients with type 2 diabetes

Previous studies showed that low serum bilirubin concentrations are associated with increased risk of cardiovascular disease. To explore this further, we evaluated the relationships between serum bilirubin concentrations and the degree of urinary albumin excretion and other markers of subclinical atherosclerosis in 633 consecutive patients with type 2 diabetes. Multiple regression analysis showed that the serum bilirubin concentration was an independent determinant of and had a significant inverse correlation to the log urinary albumin excretion. Serum bilirubin concentrations were significantly lower in patients with than in those without cardiovascular disease. A significant inverse correlation was found between the serum bilirubin concentration and pulse wave velocity, while a significant positive correlation was found to the ankle-brachial index in a subgroup of 386 patients. Our study shows that the serum bilirubin level is associated with microalbuminuria and subclinical atherosclerosis in patients with type 2 diabetes.

Serum uric acid is associated with microalbuminuria and subclinical atherosclerosis in men with type 2 diabetes mellitus

Hyperuricemia has been reported to be associated with increased risk of renal insufficiency as well as cardiovascular events. The aim of this study was to evaluate the relationships between serum uric acid concentration and degree of urinary albumin excretion as well as markers of subclinical atherosclerosis in men with type 2 diabetes mellitus. Serum uric acid concentrations were measured in 343 men with type 2 diabetes mellitus. We then evaluated relationships of serum uric acid concentrations to degree of urinary albumin excretion as well as to major cardiovascular risk factors, including age, blood pressure, serum lipid concentration, and glycemic control (hemoglobin A1c). The relationships between serum uric acid concentration and pulse wave velocity or ankle-brachial index (n=236) and between serum uric acid concentration and carotid intima-media thickness or plaque score (n=125) were investigated additionally in a subgroup of patients. Serum uric acid concentration correlated positively with logarithm of urinary albumin excretion (r=0.302, P<.0001). Positive correlation was found between serum uric acid concentration and intima-media thickness (r=0.233, P=.0087), whereas inverse correlation was found between serum uric acid concentration and ankle-brachial index (r=-0.150, P=.0207). Multiple regression analysis demonstrated that serum uric acid concentration (beta=.281, P<.0001), duration of diabetes (beta=.253, P<.0001), hemoglobin A1c (beta=.166, P=.0034), serum triglyceride concentration (beta=.125, P=.0472), and systolic blood pressure (beta=.275, P=.0013) were independent determinants of logarithm of urinary albumin excretion. In conclusion, serum uric acid concentration is associated with microalbuminuria and subclinical atherosclerosis in men with type 2 diabetes mellitus.

Visit-to-visit variability in systolic blood pressure is correlated with diabetic nephropathy and atherosclerosis in patients with type 2 diabetes

OBJECTIVE Recent studies make remarks on the effect of variability in systolic blood pressure (SBP) on the development of cardiovascular disease. The aim of this study was to investigate the relationship between the variability in SBP and the degree of diabetic nephropathy and atherosclerosis in patients with type 2 diabetes. METHODS We measured SBP in 422 consecutive patients with type 2 diabetes at every visit during a year, and we calculated the coefficient of variation (CV) of SBP. Then, we evaluated relationships of variability of SBP to degree of urinary albumin excretion (UAE), which is a useful marker for cardiovascular disease as well as diabetic nephropathy, ankle-brachial index (ABI) and pulse wave velocity (PWV). RESULTS CV of SBP positively correlated with logUAE (r=0.210, P<0.0001) or PWV (r=0.409, P<0.0001), whereas CV of SBP inversely correlated with ABI (r=-0.098, P=0.0463). Multiple regression analysis demonstrated that CV of SBP independently correlated with logUAE (β=0.149, P=0.0072), PWV (β=0.337, P<0.0001) or ABI (β=-0.162, P=0.0101). CONCLUSIONS Not only average SBP but also variability in SBP is correlated with diabetic nephropathy and atherosclerosis in patients with type 2 diabetes.

Metabolically Healthy Obesity and Risk of Incident CKD

BACKGROUND AND OBJECTIVES Metabolically healthy obesity (MHO) is a unique obesity phenotype that apparently protects people from the metabolic complications of obesity. The association between MHO phenotype and incident CKD is unclear. Thus, this study investigated the association between MHO phenotype and incident CKD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS A total of 3136 Japanese participants were enrolled in an 8-year follow-up cohort study in 2001. Metabolically healthy status was assessed by common clinical markers: BP, triglycerides, HDL cholesterol, and fasting plasma glucose concentrations. Body mass index ≥25.0 kg/m(2) was defined as obesity. CKD was defined by proteinuria or eGFR of <60 ml/min per 1.73 m(2). To calculate the odds ratio for incident CKD, logistic regression analyses were performed. RESULTS The crude incidence proportions of CKD were 2.6% (56 of 2122 participants) in participants with the metabolically healthy nonobesity phenotype, 2.6% (8 of 302) in those with the MHO phenotype, 6.7% (30 of 445) in those with the metabolically abnormal nonobesity phenotype, and 10.9% (29 of 267) in those with the metabolically abnormal obesity phenotype. Compared with metabolically healthy nonobesity phenotype, the odds ratios for incident CKD were 0.83 (95% confidence interval [95% CI], 0.36 to 1.72; P=0.64) for MHO, 1.44 (95% CI, 0.80 to 2.57; P=0.22) for metabolically abnormal nonobesity, and 2.80 (95% CI, 1.45 to 5.35; P=0.02) for metabolically abnormal obesity phenotype after adjustment for confounders, including age, sex, smoking statues, alcohol use, creatinine, uric acid, systolic BP, HDL cholesterol, and impaired fasting glucose or diabetes. CONCLUSION MHO phenotype was not associated with higher risk of incident CKD.

Visit-to-Visit Blood Pressure Variability Is a Novel Risk Factor for the Development and Progression of Diabetic Nephropathy in Patients With Type 2 Diabetes

OBJECTIVE Recent study has suggested that not only the presence of hypertension but also the variability in systolic blood pressure (SBP) are risk factors for vascular disease and organ damage. The aim of this study was to investigate the relationship between visit-to-visit variability in SBP and change in urinary albumin excretion (UAE) or development of albuminuria in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS We measured SBP in 354 consecutive patients at every visit during 1 year and calculated the coefficient of variation (CV) of SBP. We performed a follow-up study to assess change in UAE or development of albuminuria, the mean interval of which was 3.76 ± 0.71 years. Then, we evaluated relationships of variability of SBP to diabetic nephropathy using multiple regression analysis and multiple Cox regression model. RESULTS Multiple regression analysis demonstrated that CV of SBP was independently associated with change in UAE (β = 0.1758; P = 0.0108). Adjusted Cox regression analyses demonstrated that CV of SBP was associated with an increased hazard of development of albuminuria; hazard ratio was 1.143 (95% CI 1.008–1.302). CONCLUSIONS Visit-to-visit variability in SBP could be a novel risk factor for the development and progression of diabetic nephropathy in patients with type 2 diabetes.

Senescence Marker Protein-30/Gluconolactonase Deletion Worsens Glucose Tolerance through Impairment of Acute Insulin Secretion

Senescence marker protein-30 (SMP30) is an androgen-independent factor that decreases with age. We recently identified SMP30 as the lactone-hydrolyzing enzyme gluconolactonase (GNL), which is involved in vitamin C biosynthesis in animal species. To examine whether the age-related decrease in SMP30/GNL has effects on glucose homeostasis, we used SMP30/GNL knockout (KO) mice treated with L-ascorbic acid. In an ip glucose tolerance test at 15 wk of age, blood glucose levels in SMP30/GNL KO mice were significantly increased by 25% at 30 min after glucose administration compared with wild-type (WT) mice. Insulin levels in SMP30/GNL KO mice were significantly decreased by 37% at 30 min after glucose compared with WT mice. Interestingly, an insulin tolerance test showed a greater glucose-lowering effect in SMP30/GNL KO mice. High-fat diet feeding severely worsened glucose tolerance in both WT and SMP30/GNL KO mice. Morphometric analysis revealed no differences in the degree of high-fat diet-induced compensatory increase in beta-cell mass and proliferation. In the static incubation study of islets, insulin secretion in response to 20 mm glucose or KCl was significantly decreased in SMP30/GNL KO mice. On the other hand, islet ATP content at 20 mm in SMP30/GNL KO mice was similar to that in WT mice. Collectively, these data indicate that impairment of the early phase of insulin secretion due to dysfunction of the distal portion of the secretion pathway underlies glucose intolerance in SMP30/GNL KO mice. Decreased SMP30/GNL may contribute to the worsening of glucose tolerance that occurs in normal aging.

Telmisartan, an angiotensin II type 1 receptor blocker, prevents the development of diabetes in male Spontaneously Diabetic Torii rats

To assess the beneficial effects of the angiotensin II type 1 receptor blocker telmisartan on a non-obese animal model of reduced function and mass of islet beta-cells prior to the development of diabetes, Spontaneously Diabetic Torii (SDT) rats were treated with telmisartan at 8 weeks of age. At 24 weeks of age, the treatment with telmisartan dose-dependently ameliorated hyperglycemia and hypoinsulinemia, and high-dose (5 mg/kg/day) treated SDT rats did not developed diabetes. Real-time RT-PCR analysis revealed that treatment with high-dose telmisartan reduced mRNA expression of local renin-angiotensin system (RAS) components, components of NAD(P)H oxidase, transforming growth factor-beta1 and vascular endothelial growth factor in the pancreas of male SDT rats. Immunohistochemical and Western blot analyses revealed that treatment with telmisartan also reduced expression of p47(phox). These results suggest that treatment with telmisartan reduces oxidative stress by local RAS activation and protects against islet beta-cell damage and dysfunction. These findings provide at least a partial explanation for the reduced incidence of new-onset diabetes that has been observed in several clinical trials involving angiotensin II type 1 receptor blockers and ACE inhibitors.

Low serum bilirubin concentration is a predictor of chronic kidney disease.

OBJECTIVE Chronic kidney disease (CKD) is a worldwide public health problem. It is very important to identify the factors that affect CKD. Previous studies have reported that serum bilirubin concentration was positively correlated with renal function in a cross-sectional study. The aim of this study was to investigate the relationship between serum bilirubin concentration and the progression of CKD. METHODS A cohort study was performed on a consecutive series of 2784 subjects without CKD, defined as estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m(2), at baseline. We analyzed the relationship between serum total bilirubin concentration at baseline and new-onset CKD in the general population. RESULTS We followed the subjects for a median period of 7.7 years. There were 1157 females and 1627 males, and 231 females and 370 males developed CKD during this period. Multiple Cox regression analyses revealed that serum total bilirubin concentration (hazard ratio (HR) per 1.0 μmol/L increase 0.97 (95% CI 0.95-0.99), P = 0.0084) in addition to age, gamma-glutamyl transpeptidase (GGT), uric acid (UA), creatinine and medication for hypertension in men and serum total bilirubin concentration (HR per 1.0 μmol/L increase 0.96 (95% CI 0.93-1.00), P = 0.0309) in addition to age, GGT, alanine aminotransferase, UA, creatinine and medication for dyslipidemia in women were independent predictors of new-onset CKD, after adjusting for confounders. CONCLUSION Our study demonstrated that serum total bilirubin concentration could be a novel risk factor for the progression of CKD, defined as eGFR <60 ml/min/1.73 m(2), in the general population.

Impact of low‐carbohydrate diet on body composition: meta‐analysis of randomized controlled studies

The effect of low‐carbohydrate diet (LCD) on body composition, especially fat mass, in obese individuals remains to be elucidated.