Circulating microRNA profile of long-lived Okinawans identifies novel potential targets for optimizing lifespan and health span.

Nonagenarians and centenarians serve as successful examples of aging and extended longevity, showcasing robust regulation of biological mechanisms and homeostasis. Given that human longevity is a complex field of study that navigates molecular and biological mechanisms influencing aging, we hypothesized that microRNAs, a class of small noncoding RNAs implicated in regulating gene expression at the post-transcriptional level, are differentially regulated in the circulatory system of young, middle-aged, and nonagenarian individuals. We sequenced circulating microRNAs in Okinawan males and females <40, 50-80, and >90 years of age accounting for FOXO3 genetic variations of single nucleotide polymorphism (SNP) rs2802292 (TT - common vs. GT - longevity) and validated the findings through RT-qPCR. We report five microRNAs exclusively upregulated in both male and female nonagenarians with the longevity genotype, play predictive functional roles in TGF-ß, FoxO, AMPK, Pi3K-Akt, and MAPK signaling pathways. Our findings suggest that these microRNAs upregulated in nonagenarians may provide novel insight into enhanced lifespan and health span. This discovery warrants further exploration into their roles in human aging and longevity.

Role of perirenal adiposity in renal dysfunction among CKD individuals with or without diabetes: a Japanese cross-sectional study.

INTRODUCTION: It remains unclear whether increased perirenal fat (PRF) accumulation is equally related to renal involvement in patients with and without diabetes mellitus (DM). We evaluated the association between PRF volume (PRFV) and low glomerular filtration rate (GFR) and proteinuria in people with or without type 2 diabetes mellitus (T2DM). RESEARCH DESIGN AND METHODS: We performed a cross-sectional analysis of 473 individuals without T2DM (non-DM, n=202) and with T2DM (DM, n=271). PRFV (cm3), obtained from non-contrast CT, was indexed as PRF index (PRFV/body surface area, cm3/m2). Multivariate-adjusted models were used to determine the ORs of PRFV and PRFV index for detecting estimated GFR (eGFR) decrease of <60 mL/min/1.73 m2 proteinuria onset, or both. RESULTS: Although body mass index (BMI), visceral fat area, and waist circumference were comparable between the non-DM and DM groups, kidney volume, PRFV, and PRFV index were higher in individuals with T2DM than in those without T2DM. In the multivariate analysis, after adjusting for age, sex, BMI, hypertension, smoking history, and visceral fat area ≥100 cm2, the cut-off values of PRFV index were associated with an eGFR<60 in individuals with DM (OR 6.01, 95% CI 2.20 to 16.4, p<0.001) but not in those without DM. CONCLUSIONS: PRFV is associated with low eGFR in patients with T2DM but not in those without T2DM. This suggests that PRF accumulation is more closely related to the onset and progression of diabetic kidney disease (DKD) than non-DKD. Clarifying the mechanisms through which PRF influences DKD development could pave the way for novel prevention and treatment strategies.

Novel protective effect of the FOXO3 longevity genotype on mechanisms of cellular aging in Okinawans.

The genetic association of FOXO3 genotypes with human longevity is well established, although the mechanism is not fully understood. We now report on the relationship of the FOXO3 longevity variant rs2802292 with telomere length, telomerase activity, FOXO3 expression, and inflammatory cytokine levels in men and women. In agreement with earlier work, the FOXO3 longevity variant conferred protection against telomere shortening of peripheral blood mononuclear cells from adults aged 55 years and older. This was accompanied by higher levels of telomerase activity in mononuclear cells for carriers of the longevity-associated FOXO3 G-allele of SNP rs2802292 (P = 0.015). FOXO3 mRNA expression increased slightly with age in both young (P = 0.02) and old (P = 0.08) G-allele carriers. Older female G-allele carriers displayed a modest decline in levels of pro-inflammatory cytokine IL-6 with age (P = 0.07). In contrast, older male G-allele carriers displayed an age-dependent increase in levels of anti-inflammatory cytokine IL-10 with age (P = 0.04). Thus, FOXO3 may act through several different pro-longevity mechanisms, which may differ by age and sex.

Effect of dapagliflozin on 24-hour glycemic variables in Japanese patients with type 2 diabetes mellitus receiving basal insulin supported oral therapy (DBOT): a multicenter, randomized, open-label, parallel-group study.

INTRODUCTION: This study aimed to evaluate the impacts of dapagliflozin on 24-hour glucose variability and diabetes-related biochemical variables in Japanese patients with type 2 diabetes who had received basal insulin supported oral therapy (BOT). RESEARCH DESIGN AND METHODS: Changes in mean daily blood glucose level before and after 48-72 hours of add-on or no add-on of dapagliflozin (primary end point) and diabetes-related biochemical variables and major safety variables during the 12 weeks (secondary end point) were evaluated in the multicenter, randomized, two-arm, open-label, parallel-group comparison study. RESULTS: Among 36 participants, 18 were included in the no add-on group and 18 were included in the dapagliflozin add-on group. Age, gender, and body mass index were comparable between the groups. There were no changes in continuous glucose monitoring metrics in the no add-on group. In the dapagliflozin add-on group, mean glucose (183-156 mg/dL, p=0.001), maximum glucose (300-253, p<0.01), and SD glucose (57-45, p<0.05) decreased. Time in range increased (p<0.05), while time above the range decreased in the dapagliflozin add-on group but not in the no add-on group. After 12-week treatment with dapagliflozin add-on, 8-hydroxy-2'-deoxyguanosine (8OHdG), as well as hemoglobin A1c (HbA1c), decreased. CONCLUSIONS: This study showed that the mean daily blood glucose and other daily glucose profiles were amended after 48-72 hours of dapagliflozin add-on in Japanese patients with type 2 diabetes who received BOT. The diabetes-related biochemical variables such as HbA1c and urinary 8OHdG were also obtained during the 12 weeks of dapagliflozin add-on without major adverse events. A preferable 24-hour glucose profile in 'time in ranges' and an improvement in reactive oxygen species by dapagliflozin warrant us to evaluate these benefits in larger clinical studies. TRIAL REGISTRATION NUMBER: UMIN000019457.

Risk Classification for Metabolic Syndrome and the Incidence of Cardiovascular Disease in Japan With Low Prevalence of Obesity: A Pooled Analysis of 10 Prospective Cohort Studies.

Background It is uncertain whether risk classification under the nationwide program on screening and lifestyle modification for metabolic syndrome captures well high-risk individuals who could benefit from lifestyle interventions. We examined the validity of risk classification by linking the incidence of cardiovascular disease (CVD). Methods and Results Individual-level data of 29 288 Japanese individuals aged 40 to 74 years without a history of CVD from 10 prospective cohort studies were used. Metabolic syndrome was defined as the presence of high abdominal obesity and/or overweight plus risk factors such as high blood pressure, high triglyceride or low high-density lipoprotein cholesterol levels, and high blood glucose levels. The risk categories for lifestyle intervention were information supply only, motivation-support intervention, and intensive support intervention. Sex- and age-specific hazard ratios and population attributable fractions of CVD, which were also further adjusted to consider non-high density lipoprotein cholesterol levels, were estimated with reference to nonobese/overweight individuals, using Cox proportional hazard regression. Since the reference category included those with risk factors, we set a supernormal group (nonobese/overweight with no risk factor) as another reference. We documented 1023 incident CVD cases (565 men and 458 women). The adjusted CVD risk was 60% to 70% higher in men and women aged 40 to 64 years receiving an intensive support intervention, and 30% higher in women aged 65 to 74 years receiving a motivation-support intervention, compared with nonobese/overweight individuals. The population attributable fractions in men and women aged 40 to 64 years receiving an intensive support intervention were 17.7% and 6.6%, respectively, while that in women aged 65 to 74 years receiving a motivation-support intervention was 9.4%. Compared with the supernormal group, nonobese/overweight individuals with risk factors had similar hazard ratios and population attributable fractions as individuals with metabolic syndrome. Conclusions Similar CVD excess and attributable risks among individuals with metabolic syndrome components in the absence and presence of obesity/overweight imply the need for lifestyle modification in both high-risk groups.

High FIB4 index is an independent risk factor of diabetic kidney disease in type 2 diabetes.

Nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) may be linked to development of chronic kidney diseases (CKD). The FIB4 index, a noninvasive liver fibrosis score, has been reported to predict CKD in non-diabetic patients, but there are no reports yet in diabetic cases. Therefore, we evaluated the prognostic impact of FIB4 index on the risk of developing diabetic kidney disease (DKD) in Japanese patients with type 2 diabetes in a retrospective cohort study. We assessed patients with type 2 diabetes with an eGFR ≥ 60 mL/min/1.73 m2 and without dipstick positive proteinuria (≥ 1 +) at their first visit to our department. Participants were divided into two groups based on the FIB4 index at their first visit: FIB4 index > 1.3 and FIB4 index ≤ 1.3. The primary endpoint was defined as a decrease in eGFR < 60 mL/min/1.73 m2 or the onset of proteinuria during the course of treatment. The average age of all 584 type 2 diabetic participants (360 [61.6%] men) was 55 ± 11 years. There were 187 patients in the FIB4 index group > 1.3 (32.0%) and the median observation period was 6.0 (3.8-11.0) years. Kaplan-Meier survival analysis indicated that the risks of developing DKD, eGFR < 60 and proteinuria were all higher in FIB4 index > 1.3 patients than in FIB4 ≤ 1.3 patients. In the Cox regression analysis, an FIB4 index > 1.3 was a significant predictor for onset of DKD (HR 1.54, 95% CI 1.15-2.08) and proteinuria (HR 1.55, 95% CI 1.08-2.23), but not for an eGFR < 60 (HR 1.14, 95% CI 0.79-1.99). To the best of our knowledge, this is the first study to demonstrate that an FIB4 index > 1.3 has a prognostic impact on the development of CKD and proteinuria in type 2 diabetic patients. This warrants further investigation of the prognostic impact of the development of DKD or proteinuria.

Regional Variations of Insulin Secretion and Insulin Sensitivity in Japanese Participants With Normal Glucose Tolerance.

Purpose: Regional differences in dietary patterns in Asian countries might affect the balance of insulin response and sensitivity. However, this notion is yet to be validated. To clarify the regional differences in the insulin response and sensitivity and their relationship to nutrients, we compared the insulin secretory response during an oral glucose tolerance test in Japanese participants. Methods: This observational retrospective cohort study analyzed the data from participants with normal glucose tolerance (NGT) from four distinct areas of Japan with regard to the food environment: Fukushima, Nagano, Tokushima, and Okinawa based on data available in the Japanese National Health Insurance database. Results: Although the glucose levels were comparable among the four regions, the insulin responses were significantly different among the regions. This difference was observed even within the same BMI category. The plot between the insulin sensitivity index (Matsuda index) and insulinAUC/glucoseAUC or the insulinogenic index showed hyperbolic relationships with variations in regions. The indices of insulin secretion correlated positively with fat intake and negatively with the intake of fish, carbohydrate calories, and dietary fiber. Conclusions: We found that significant regional differences in insulin response and insulin sensitivity in Japanese participants and that nutritional factors may be linked to these differences independently of body size/adiposity. Insulin response and insulin sensitivity can vary among adult individuals, even within the same race and the same country, and are likely affected by environmental/lifestyle factors as well as genetic traits.

Retrospective exploratory analyses on gender differences in determinants for incidence and progression of diabetic retinopathy in Japanese patients with type 2 diabetes mellitus.

Gender differences in risks for macrovascular complications in type 2 diabetes mellitus (T2DM) have been well established. However, the impact of gender differences on diabetic retinopathy (DR) has not been fully elucidated. We therefore retrospectively explored gender-specific determinants for DR in patients with T2DM in a small sized Japanese cohort in Okinawa. There were 214 patients who were diagnosed as no DR (n = 142) and non-proliferative DR (n = 72) in 2009. During the follow-up of median 7 years, 41/142 of incidence, 26/72 of progression, and 67/214 of incidence and progression were observed, respectively. DR was assessed using the modified international clinical DR severity scales. The risks for incidence, progression as well as incidence and progression of DR were comparable between men and women, respectively. Cox proportional hazard models in multivariate analyses demonstrated that the only common determinant in both men and women for DR was the duration of T2DM. Regarding gender-specific determinants, lower level of serum albumin in men as well as higher HbA1c, lower level of estimated glomerular filtration rate, and lower level of serum uric acid in women were extracted, respectively. Although precise mechanisms for such gender-specific determinants of DR still remain unsolved, the present study would highlight a couple of factors associated with gender-specific determinants for DR in a limited numbers of Japanese cohort. Prospective observational studies on gender-specific determinants of DR in a large scale cohort are warranted to further clarify underlying mechanisms.

Novel STAR gene variant in a patient with classic lipoid congenital adrenal hyperplasia and combined pituitary hormone deficiency.

We report the first case of classic lipoid congenital adrenal hyperplasia and combined pituitary hormone deficiency. We identified pathogenic variants in the STAR gene: a novel variant of c.126_127delCCinsG, namely, p.Thr44Profs*2 and an already reported variant of c.634C>T, namely, p.Gln212*. The association with combined pituitary hormone deficiency might be just a coincidence.

Age-Dependent Efficacy of Ezetimibe for Low-Density Lipoprotein Cholesterol Reduction in Japanese Patients with or without Type 2 Diabetes Mellitus.

Ezetimibe reduces cardiovascular risk by lowering the levels of low-density lipoprotein cholesterol (LDL-C). However, there is limited information regarding the factors associated with ezetimibe-mediated LDL-C reduction. We investigated the factors associated with LDL-C reduction after ezetimibe administration in Japanese patients with or without type 2 diabetes mellitus (T2DM). This single-center retrospective observational study enrolled a total of 266 consecutive ezetimibe-naïve patients, of which 154 were excluded because of either switching from statin or fenofibrate to ezetimibe (n = 52) or ezetimibe discontinuation (n = 102). Finally, 112 patients were eligible for analysis. To identify the factors influencing LDL-C levels, univariate and multivariate linear regression analyses were performed after 52 weeks of ezetimibe treatment. Overall, advanced age, T2DM, and high baseline LDL-C were significantly associated with a greater decrease in LDL-C levels. In the non-T2DM group, advanced age and high baseline LDL-C were associated with greater decrease in LDL-C levels. In the T2DM group, baseline LDL-C was the only factor that influenced the change in LDL-C levels. Advanced age was significantly associated with higher LDL-C reduction in non-T2DM patients, but not in T2DM patients. Ezetimibe use might be beneficial in older patients without T2DM. The lack of association between age and the LDL-C lowering effect by ezetimibe in patients with T2DM may be due to yet unknown mechanism except low statistical power.

Dissimilar Effects of Anagliptin and Sitagliptin on Lipoprotein Subclass in Standard or Strong Statin-Treated Patients with Type-2 Diabetes Mellitus: A Subanalysis of the REASON (Randomized Evaluation of Anagliptin versus Sitagliptin on Low-Density LipoproteiN Cholesterol in Diabetes) Trial.

The effects of antidiabetic agents on lipoprotein subclasses are assumed to be pivotal, but this assumption has not been studied. We evaluated lipoprotein subclasses in patients, randomly selected from REASON (Randomized Evaluation of Anagliptin versus Sitagliptin On low-density lipoproteiN cholesterol in diabetes) Trial participants, with type-2 diabetes treated with either anagliptin or sitagliptin. We measured total cholesterol (TC) and triglycerides (TG) in 4 (chylomicron (CM), very low-density lipoprotein (VLDL), low density lipoprotein (LDL), and high-density lipoprotein (HDL)) lipoprotein classes and 20 (2 CM, 5 VLDL, 6 LDL, and 7 HDL) lipoprotein subclasses. Between 0 and 52 weeks, TC and TG in lipoprotein and the lipoprotein subclass were distributed differently in patients treated with anagliptin and sitagliptin. The preferable changes in TC and TG levels were observed dominantly in the anagliptin-treated group under standard statin therapy, but the benefits were observed in both the anagliptin- and sitagliptin-treated groups, at least partially under strong statin therapy. In future studies, the atherogenic properties of lipoprotein subclasses might be considered when employing antidiabetic dipeptidyl peptidase-4 (DPP-4) inhibitors, especially in patients with type-2 diabetes who are at risk of atherosclerotic cardiovascular disease (ASCVD) or are undergoing statin treatment.

Minimal Shortening of Leukocyte Telomere Length Across Age Groups in a Cross-Sectional Study for Carriers of a Longevity-Associated FOXO3 Allele.

FOXO3 is one of the most prominent genes demonstrating a consistently reproducible genetic association with human longevity. The mechanisms by which these individual gene variants confer greater organismal lifespan are not well understood. We assessed the effect of longevity-associated FOXO3 alleles on age-related leukocyte telomere dynamics in a cross-sectional study comprised of samples from 121 healthy Okinawan-Japanese donors aged 21-95 years. We found that telomere length for carriers of the longevity associated allele of FOXO3 single nucleotide polymorphism rs2802292 displayed no significant correlation with age, an effect that was most pronounced in older (>50 years of age) participants. This is the first validated longevity gene variant identified to date showing an association with negligible loss of telomere length with age in humans in a cross-sectional study. Reduced telomere attrition may be a key mechanism for the longevity-promoting effect of the FOXO3 genotype studied.

A novel insulinotropic mechanism of whole grain-derived γ-oryzanol via the suppression of local dopamine D2 receptor signalling in mouse islet.

BACKGROUND AND PURPOSE: γ-Oryzanol, derived from unrefined rice, attenuated the preference for dietary fat in mice, by decreasing hypothalamic endoplasmic reticulum stress. However, no peripheral mechanisms, whereby γ-oryzanol could ameliorate glucose dyshomeostasis were explored. Dopamine D2 receptor signalling locally attenuates insulin secretion in pancreatic islets, presumably via decreased levels of intracellular cAMP. We therefore hypothesized that γ-oryzanol would improve high-fat diet (HFD)-induced dysfunction of islets through the suppression of local D2 receptor signalling. EXPERIMENTAL APPROACH: Glucose metabolism and regulation of molecules involved in D2 receptor signalling in pancreatic islets were investigated in male C57BL/6J mice, fed HFD and treated with γ-oryzanol . In isolated murine islets and the beta cell line, MIN6 , the effects of γ-oryzanol on glucose-stimulated insulin secretion (GSIS) was analysed using siRNA for D2 receptors and a variety of compounds which alter D2 receptor signalling. KEY RESULTS: In islets, γ-oryzanol enhanced GSIS via the activation of the cAMP/PKA pathway. Expression of molecules involved in D2 receptor signalling was increased in islets from HFD-fed mice, which were reciprocally decreased by γ-oryzanol. Experiments with siRNA for D2 receptors and D2 receptor ligands in vitro suggest that γ-oryzanol suppressed D2 receptor signalling and augmented GSIS. CONCLUSIONS AND IMPLICATIONS: γ-Oryzanol exhibited unique anti-diabetic properties. The unexpected effects of γ-oryzanol on D2 receptor signalling in islets may provide a novel; natural food-based, approach to anti-diabetic therapy.

Subclinical Carotid Atherosclerosis Burden in the Japanese: Comparison between Okinawa and Nagano Residents.

AIM: The prevalence of overweight and a change in atherosclerotic lipid profiles may be linked to region-specific differences in atherosclerotic diseases. We evaluated whether the lipid phenotype could be linked to region- and sex-specific differences in the degree of atherosclerosis. METHODS: Non-diabetic subjects included Okinawa (n=1674) and Nagano (n=1392) residents aged 30-75 years who underwent carotid ultrasonography for the measurement of maximum intima-media thickness (max IMT). RESULTS: Average max IMT was higher in Okinawa men and women, and the increase in max IMT with age was enhanced in men. Multiple regression analysis showed that in addition to age and systolic blood pressure, low-density lipoprotein cholesterol and non-high-density lipoprotein cholesterol were IMT determinants only in men for both Okinawa and Nagano. Meanwhile, HDL-cholesterol was a determinant for Okinawa men and women, but not for Nagano men and women. CONCLUSIONS: This is the first report to show region- and sex-specific differences in the determinants for max IMT in a Japanese population. The evaluation of the relationship between lipid profile patterns and region- and sex-specific differences in carotid atherosclerosis burden may be required.

γ-Oryzanol protects pancreatic ß-cells against endoplasmic reticulum stress in male mice.

Endoplasmic reticulum (ER) stress is profoundly involved in dysfunction of ß-cells under high-fat diet and hyperglycemia. Our recent study in mice showed that γ-oryzanol, a unique component of brown rice, acts as a chemical chaperone in the hypothalamus and improves feeding behavior and diet-induced dysmetabolism. However, the entire mechanism whereby γ-oryzanol improves glucose metabolism throughout the body still remains unclear. In this context, we tested whether γ-oryzanol reduces ER stress and improves function and survival of pancreatic ß-cells using murine ß-cell line MIN6. In MIN6 cells with augmented ER stress by tunicamycin, γ-oryzanol decreased exaggerated expression of ER stress-related genes and phosphorylation of eukaryotic initiation factor-2α, resulting in restoration of glucose-stimulated insulin secretion and prevention of apoptosis. In islets from high-fat diet-fed diabetic mice, oral administration of γ-oryzanol improved glucose-stimulated insulin secretion on following reduction of exaggerated ER stress and apoptosis. Furthermore, we examined the impact of γ-oryzanol on low-dose streptozotocin-induced diabetic mice, where exaggerated ER stress and resultant apoptosis in ß-cells were observed. Also in this model, γ-oryzanol attenuated mRNA level of genes involved in ER stress and apoptotic signaling in islets, leading to amelioration of glucose dysmetabolism. Taken together, our findings demonstrate that γ-oryzanol directly ameliorates ER stress-induced ß-cell dysfunction and subsequent apoptosis, highlighting usefulness of γ-oryzanol for the treatment of diabetes mellitus.

Effects of the brown rice diet on visceral obesity and endothelial function: the BRAVO study.

Brown rice (BR) and white rice (WR) produce different glycaemic responses and their consumption may affect the dietary management of obesity. In the present study, the effects of BR and WR on abdominal fat distribution, metabolic parameters and endothelial function were evaluated in subjects with the metabolic syndrome in a randomised cross-over fashion. In study 1, acute postprandial metabolic parameters and flow- and nitroglycerine-mediated dilation (FMD and NMD) of the brachial artery were determined in male volunteers with or without the metabolic syndrome after ingestion of either BR or WR. The increases in glucose and insulin AUC were lower after ingestion of BR than after ingestion of WR (P= 0·041 and P= 0·045, respectively). FMD values were decreased 60 min after ingestion of WR (P= 0·037 v. baseline), but the decrease was protected after ingestion of BR. In study 2, a separate cohort of male volunteers (n 27) with the metabolic syndrome was randomised into two groups with different BR and WR consumption patterns. The values of weight-based parameters were decreased after consumption of BR for 8 weeks, but returned to baseline values after a WR consumption period. Insulin resistance and total cholesterol and LDL-cholesterol levels were reduced after consumption of BR. In conclusion, consumption of BR may be beneficial, partly owing to the lowering of glycaemic response, and may protect postprandial endothelial function in subjects with the metabolic syndrome. Long-term beneficial effects of BR on metabolic parameters and endothelial function were also observed.

Lipid deposition in various sites of the skeletal muscles and liver exhibits a positive correlation with visceral fat accumulation in middle-aged Japanese men with metabolic syndrome.

Objective In addition to excess visceral fat, lipid deposition in the liver and skeletal muscle has been implicated in the pathophysiology of type 2 diabetes and metabolic syndrome. This study was designed to explore the relationship between hepatic and muscular lipid deposition and visceral fat accumulation in 105 middle-aged men with metabolic syndrome. Methods Abdominal computed tomography (CT) was used to simultaneously evaluate the visceral fat area (VFA) and CT Hounsfield unit (HU) values of three different portions of skeletal muscle and the liver. Results A significant inverse correlation was observed between the VFA and the CT HU values of the iliopsoas muscle, back muscle, rectus abdominis muscle and liver. Three types of interventions, i.e., lifestyle modification and treatment with antidiabetic drugs, such as Pioglitazone or Miglitol, caused significant decreases in visceral fat accumulation. The extent of lipid deposition in the liver was strongly correlated with the levels of glucose-lipid metabolic markers, which decreased significantly following Pioglitazone treatment. On the other hand, the amount of lipid deposition in the three skeletal muscles and the liver did not decrease after Miglitol treatment. Conclusion Visceral fat accumulation is accompanied by excess lipid deposition in skeletal muscle and the liver in patients with metabolic syndrome. The CT-based simultaneous, concise evaluations of ectopic lipid deposition and visceral fat mass used in the present study may provide unique information for assessing cardiometabolic risks and the therapeutic impact in patients with diabetes-obesity syndrome.

Ectopic fat deposition and global cardiometabolic risk: new paradigm in cardiovascular medicine.

The obesity epidemic is a global public health concern that increases the likelihood of morbidity and mortality of metabolic and cardiovascular disease (CVD) and threatens to reduce life expectancy around the world. The concept of the metabolic syndrome (MetS) takes into account that visceral fat plays an essential role in the development of metabolic and cardiovascular diseases. However, MetS cannot be used to assess global CVD risk but is at best one more modifiable CVD risk factor. Thus, global cardiometabolic risk (the global risk of cardiovascular disease resulting from traditional risk factors combined with the additional contribution of the metabolic syndrome and/or insulin resistance) should be considered individually. There is solid evidence supporting the notion that excess abdominal fat is predictive of insulin resistance and the presence of related metabolic abnormalities currently referred to as MetS. Despite the fact that abdominal obesity is a highly prevalent feature of MetS, the mechanisms by which abdominal obesity is causally related to MetS are not fully elucidated. Besides visceral fat accumulation, ectopic lipid deposition, especially in liver and skeletal muscle, has been implicated in the pathophysiology of diabetes, insulin resistance and obesity-related disorders. Also, ectopic fat deposition could be deteriorated in the heart components such as (1) circulatory and locally recruited fat, (2) intra- and extra-myocellular fat, (3) perivascular fat, and (4) pericardial fat. In this review, the contribution of ectopic lipid deposition to global cardiometabolic risk is reviewed and also discussed are potential underlying mechanisms including adipocytokine, insulin resistance and lipotoxicity.

Miglitol, α-glycosidase inhibitor, reduces visceral fat accumulation and cardiovascular risk factors in subjects with the metabolic syndrome: a randomized comparable study.

BACKGROUND/OBJECTIVES: Visceral fat obesity plays an essential role in the clustering of cardiovascular risk factors. This study aimed to clarify the effects of miglitol, α-glycosidase inhibitor, on body weight, fat distribution and cardiovascular risk factors in patients with the metabolic syndrome. METHODS AND RESULTS: One hundred and eleven drug naive patients with the metabolic syndrome were continuously recruited and randomly allocated to a group of life style modification (LSM) alone or a group of LSM with miglitol per os 50 mg × 3 (LSM+miglitol). After 12 weeks of treatment, body weight (5.1%), body mass index (4.9%) and waist circumference were greatly reduced in miglitol group (n=42) than in LSM group (n=43). Plasma levels of insulin and glucose during an oral 75 g glucose loading were decreased only in miglitol group. Visceral fat area, determined by abdominal computed tomography, was greatly reduced in miglitol group (baseline 188 vs 12 weeks 161 cm(2), p<0.0001) than in LSM group (184 vs 174 cm(2), p<0.05). Subcutaneous fat area was reduced only in miglitol group (p<0.001). Systolic blood pressure was reduced in miglitol group (142 vs 133 mm Hg, p<0.001), but not in control group (137 vs 134 mm Hg). Serum levels of triglyceride, LDL-cholesterol, γ-GTP, and high-sensitive CRP were decreased and adiponectin was increased only in miglitol group. CONCLUSIONS: Our results indicated that miglitol showed an anti-obesity potential, which was achieved by reducing abdominal fat accumulation and/or enhanced insulin requirement, and then corrected both the metabolic and hemodynamic aberrations seen in patients with the metabolic syndrome (UMIN Clinical Trial Registry UMIN000007650).

Brown rice and its component, γ-oryzanol, attenuate the preference for high-fat diet by decreasing hypothalamic endoplasmic reticulum stress in mice.

Brown rice is known to improve glucose intolerance and prevent the onset of diabetes. However, the underlying mechanisms remain obscure. In the current study, we investigated the effect of brown rice and its major component, γ-oryzanol (Orz), on feeding behavior and fuel homeostasis in mice. When mice were allowed free access to a brown rice-containing chow diet (CD) and a high-fat diet (HFD), they significantly preferred CD to HFD. To reduce hypothalamic endoplasmic reticulum (ER) stress on an HFD, mice were administered with 4-phenylbutyric acid, a chemical chaperone, which caused them to prefer the CD. Notably, oral administration of Orz, a mixture of major bioactive components in brown rice, also improved glucose intolerance and attenuated hypothalamic ER stress in mice fed the HFD. In murine primary neuronal cells, Orz attenuated the tunicamycin-induced ER stress. In luciferase reporter assays in human embryonic kidney 293 cells, Orz suppressed the activation of ER stress-responsive cis-acting elements and unfolded protein response element, suggesting that Orz acts as a chemical chaperone in viable cells. Collectively, the current study is the first demonstration that brown rice and Orz improve glucose metabolism, reduce hypothalamic ER stress, and, consequently, attenuate the preference for dietary fat in mice fed an HFD.