Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 323
Filter
Add more filters

Publication year range
1.
Cereb Cortex ; 33(23): 11225-11234, 2023 11 27.
Article in English | MEDLINE | ID: mdl-37757477

ABSTRACT

Insulin resistance may lead to structural and functional abnormalities of the human brain. However, the mechanism by which insulin resistance impairs the brain remains elusive. In this study, we used two large neuroimaging databases to investigate the brain regions where insulin resistance was associated with the gray matter volume and to examine the resting-state functional connectivity between these brain regions and each hypothalamic nucleus. Insulin resistance was associated with reduced gray matter volume in the regions of the default-mode and limbic networks in the cerebral cortex in older adults. Resting-state functional connectivity was prominent between these networks and the paraventricular nucleus of the hypothalamus, a hypothalamic interface connecting functionally with the cerebral cortex. Furthermore, we found a significant correlation in these networks between insulin resistance-related gray matter volume reduction and network paraventricular nucleus of the hypothalamus resting-state functional connectivity. These results suggest that insulin resistance-related gray matter volume reduction in the default-mode and limbic networks emerged through metabolic homeostasis mechanisms in the hypothalamus.


Subject(s)
Gray Matter , Insulin Resistance , Humans , Aged , Gray Matter/diagnostic imaging , Default Mode Network , Brain Mapping/methods , Magnetic Resonance Imaging , Brain/diagnostic imaging , Cerebral Cortex
2.
BMC Geriatr ; 24(1): 614, 2024 Jul 18.
Article in English | MEDLINE | ID: mdl-39026160

ABSTRACT

BACKGROUND: With the aging of the population worldwide, extending healthy life expectancy is an urgent issue. Muscle mass has been reported to be associated with physical independence and longevity. This study aimed to investigate the characteristics of food intake in urban community-dwelling older adults with low muscle mass. METHODS: This cross-sectional study used baseline data from the Bunkyo Health Study, which included 1618 urban community-dwelling older adults aged 65-84 years. All participants underwent measurement of body composition using bioelectrical impedance analysis and evaluation of nutrient and food intake using the brief-type self-administered diet history questionnaire. Participants were stratified by sex and divided into robust or low skeletal muscle mass index (SMI) groups according to the Asian Working Group for Sarcopenia criteria to compare differences in nutrient and food intake. RESULTS: The mean age and body mass index were 73.1 ± 5.4 years and 22.6 ± 3.1 kg/m2, respectively. The prevalence of low SMI was 31.1% in men and 43.3% in women. In men, all food intake, including total energy intake, was similar between the low SMI group and the robust group. In women, the low SMI group had less total energy intake, and consumed lower amounts of energy-producing nutrients (protein, fat, and carbohydrates), but there were only small differences in the intake of specific foods. CONCLUSIONS: There were sex differences in food intake characteristics between urban community-dwelling older adults with low SMI and those who were robust. Advising women to increase their energy intake may be important in preventing muscle loss, and further research is needed in men.


Subject(s)
Independent Living , Sarcopenia , Urban Population , Humans , Aged , Male , Female , Cross-Sectional Studies , Aged, 80 and over , Independent Living/trends , Sarcopenia/epidemiology , Urban Population/trends , Diet , Japan/epidemiology , Body Composition/physiology , Muscle, Skeletal/physiology , Eating/physiology , Energy Intake/physiology
3.
Neurobiol Dis ; 177: 105990, 2023 02.
Article in English | MEDLINE | ID: mdl-36621631

ABSTRACT

OBJECTIVE: The glymphatic system is a glial-based perivascular network that promotes brain metabolic waste clearance. Reduced glymphatic flow has been observed in rat models of type 2 diabetes and hypertension, indicating the role of vascular risk factors in the glymphatic system. However, little is known about how vascular risk factors affect the human glymphatic system. The present study aims to assess the relationships between metabolic syndrome (MetS), a cluster of vascular risk factors, and the glymphatic system function using diffusion magnetic resonance imaging (MRI)-based measures of water diffusivity in the glymphatic compartments, including the brain interstitial space and perivascular spaces around the deep medullary vein. We hypothesized that vascular risk factors are associated with glymphatic dysfunction, leading to cognitive impairment in older adults. METHODS: This cross-sectional study assessed 61 older adults (age range, 65-82 years) who had participated in the Bunkyo Health Study, including 15 healthy controls (mean age, 70.87 ± 4.90 years) and 46 individuals with MetS (mean age, 71.76 ± 4.61 years). Fractional volume of extracellular-free water (FW) and an index of diffusion tensor imaging along the perivascular space (DTI-ALPS) were used as indirect indicators of water diffusivity in the interstitial extracellular and perivenous spaces of white matter, respectively. RESULTS: After adjusting for age, sex, years of education, total Fazekas scale, Pittsburgh sleep quality index (PSQI) score, and intracranial volume (ICV), a significantly (P = 0.030; Cohen's d = 1.01) higher FW was observed in individuals with MetS than in the healthy controls. Furthermore, individuals with MetS had a significantly (P = 0.031; Cohen's d = 0.86) lower ALPS index than the healthy controls, with age, sex, years of education, total Fazekas scale, PSQI score, ICV, fractional anisotropy, and mean diffusivity included as confounding factors. Higher FW was significantly associated with lower ALPS index (r = -0.37; P = 0.004). Multiple linear regression (MLR) with backward elimination analyses showed that higher diastolic blood pressure (BP; standardized ß = 0.33, P = 0.005) was independently associated with higher FW, whereas higher fasting plasma glucose levels (standardized ß = -0.63, P = 0.002) or higher Brinkman index of cigarette consumption cumulative amount (standardized ß = -0.27, P = 0.022) were associated with lower ALPS index. The lower ALPS index (standardized ß, 0.28; P = 0.040) was associated with poorer global cognitive performance, which was determined using the Japanese version of the Montreal Cognitive Assessment (MOCA-J) scores. Finally, partial correlation analyses showed a significant correlation between higher FW and lower MOCA-J scores (r = -0.35; P = 0.025) and between higher FW and higher diastolic BP (r = 0.32, P = 0.044). CONCLUSION: The present study shows the changes in diffusion MRI-based measures reflected by the higher FW and lower ALPS index in older adults with MetS, possibly due to the adverse effect of vascular risk factors on the glymphatic system. Our findings also indicate the associations between the diffusion MRI-based measures and elevated diastolic BP, hyperglycemia, smoking habit, and poorer cognitive performance. However, owing to the limitations of this study, the results should be cautiously interpreted.


Subject(s)
Diabetes Mellitus, Type 2 , Glymphatic System , Metabolic Syndrome , Humans , Animals , Rats , Aged , Aged, 80 and over , Glymphatic System/diagnostic imaging , Diffusion Tensor Imaging , Metabolic Syndrome/diagnostic imaging , Cross-Sectional Studies , Neuroimaging , Water
4.
Exp Physiol ; 108(7): 940-945, 2023 07.
Article in English | MEDLINE | ID: mdl-37074636

ABSTRACT

NEW FINDINGS: What is the central question of this study? Ageing leads to a loss of mass in skeletal muscle, but the effect of obesity on ageing-related muscle wasting is unclear. In this study, we aimed to demonstrate the specific effect of obesity on fast-twitch skeletal muscle in ageing. What is the main finding and its importance? Our findings show that the obesity induced by long-term ingestion of a high-fat diet does not aggravate muscle wasting in fast-twitch skeletal muscle of aged mice, indicating that the present study provides morphological characteristics for skeletal muscle of sarcopenic obesity. ABSTRACT: Obesity and ageing reduce muscle mass and lead to deficits in muscle maintenance, but it is not known whether obesity accelerates muscle wasting additively in the setting of ageing. We investigated morphological characteristics in fast-twitch extensor digitorum longus (EDL) muscle of mice fed a low-fat diet (LFD) or a high-fat diet (HFD) for 4 or 20 months. The fast-twitch EDL muscle was harvested, and the muscle fibre-type composition, individual muscle cross-sectional area and myotube diameter were measured. We found an increase in the percentage of type IIa and IIx myosin heavy chain fibres in the whole EDL muscle, but a decrease in type IIB myosin heavy chain in both HFD protocols. The cross-sectional area and myofibre diameter were lower in both groups of aged mice (after 20 months of LFD or HFD) compared with young mice (after 4 months of the diets), but there were no differences between mice fed LFD or HFD for 20 months. These data suggest that long-term feeding of HFD does not aggravate muscle wasting in fast-twitch EDL muscle of male mice.


Subject(s)
Muscle Fibers, Fast-Twitch , Muscle Fibers, Slow-Twitch , Mice , Male , Animals , Diet, High-Fat/adverse effects , Myosin Heavy Chains , Muscle, Skeletal/physiology , Muscular Atrophy/etiology , Obesity
5.
Am J Physiol Endocrinol Metab ; 321(6): E766-E781, 2021 12 01.
Article in English | MEDLINE | ID: mdl-34719943

ABSTRACT

Physical inactivity impairs muscle insulin sensitivity. However, its mechanism is unclear. To model physical inactivity, we applied 24-h hind-limb cast immobilization (HCI) to mice with normal or high-fat diet (HFD) and evaluated intramyocellular lipids and the insulin signaling pathway in the soleus muscle. Although 2-wk HFD alone did not alter intramyocellular diacylglycerol (IMDG) accumulation, HCI alone increased it by 1.9-fold and HCI after HFD further increased it by 3.3-fold. Parallel to this, we found increased protein kinase C ε (PKCε) activity, reduced insulin-induced 2-deoxyglucose (2-DOG) uptake, and reduced phosphorylation of insulin receptor ß (IRß) and Akt, key molecules for insulin signaling pathway. Lipin1, which converts phosphatidic acid to diacylglycerol, showed increase of its activity by HCI, and dominant-negative lipin1 expression in muscle prevented HCI-induced IMDG accumulation and impaired insulin-induced 2-DOG uptake. Furthermore, 24-h leg cast immobilization in human increased lipin1 expression. Thus, even short-term immobilization increases IMDG and impairs insulin sensitivity in muscle via enhanced lipin1 activity.NEW & NOTEWORTHY Physical inactivity impairs muscle insulin sensitivity. However, its mechanism is unclear. To model physical inactivity, we applied 24-h hind-limb cast immobilization to mice with normal or high-fat diet and evaluated intramyocellular lipids and the insulin signaling pathway in the soleus muscle. We found that even short-term immobilization increases intramyocellular diacylglycerol and impairs insulin sensitivity in muscle via enhanced lipin1 activity.


Subject(s)
Diglycerides/metabolism , Insulin Resistance , Muscle, Skeletal/metabolism , Phosphatidate Phosphatase/metabolism , Sedentary Behavior , Adult , Animals , Casts, Surgical , Hindlimb Suspension , Humans , Insulin/metabolism , Insulin Resistance/physiology , Male , Mice , Mice, Inbred C57BL , Muscle, Skeletal/pathology , Signal Transduction/physiology , Time Factors , Young Adult
6.
Diabetes Obes Metab ; 23(5): 1092-1100, 2021 05.
Article in English | MEDLINE | ID: mdl-33377253

ABSTRACT

AIM: To investigate whether changes in endogenous glucose production (EGP) and insulin and glucagon levels are elicited by the decrease in plasma glucose (PG) levels induced by the sodium-glucose co-transporter-2 (SGLT2) inhibitor tofogliflozin. MATERIALS AND METHODS: We evaluated EGP in 12 Japanese patients with type 2 diabetes under the conditions of no drugs administered (CON), single administration of the SGLT2 inhibitor tofogliflozin (TOF), and single administration of TOF with adjustment of PG levels with exogenous glucose infusion to mimic changes in PG levels observed with CON (TOF + G). We evaluated changes in EGP and levels of C-peptide and glucagon from baseline to 180 minutes after drug administration. RESULTS: Endogenous glucose production decreased in the CON (-0.22 ± 0.11 mg/kg·min) and TOF + G experiments (-0.31 ± 0.24 mg/kg·min), but not in the TOF experiment (+0.08 ± 0.19 mg/kg·min). The decrease in C-peptide was significantly greater in the TOF experiment (-0.11 ± 0.06 nmol/L) than in the CON (-0.03 ± 0.06 nmol/L) and the TOF + G experiments (-0.01 ± 0.11 nmol/L), while the increase in glucagon was significantly greater in the TOF experiment (+11.1 ± 6.3 pmol/L), but not in the TOF + G experiment (+8.6 ± 7.6 pmol/L) compared to the CON experiment (+5.1 ± 4.3 pmol/L). CONCLUSIONS: These results indicate that the decrease in PG levels induced by SGLT2 inhibitor administration is required for the increase in EGP and decrease in insulin secretion.


Subject(s)
Diabetes Mellitus, Type 2 , Pharmaceutical Preparations , Sodium-Glucose Transporter 2 Inhibitors , Benzhydryl Compounds , Blood Glucose , Diabetes Mellitus, Type 2/drug therapy , Glucose , Glucosides , Humans , Insulin/metabolism , Sodium , Sodium-Glucose Transporter 2
7.
Diabetes Obes Metab ; 20(9): 2200-2209, 2018 09.
Article in English | MEDLINE | ID: mdl-29766636

ABSTRACT

AIMS: This double-blind, randomized, placebo-controlled trial (ClinicalTrials.gov NCT02453555) evaluated the efficacy and safety of empagliflozin (Empa) 10 or 25 mg as add-on to linagliptin (Lina) 5 mg (fixed-dose combination, Empa/Lina 10/5 or 25/5) in insufficiently controlled Japanese type 2 diabetes patients. METHODS: The trial (40 sites; May 2015-March 2017) involved screening 433 adults (≥20 years) who were treatment-naive or were using one oral antidiabetic drug for ≥12 weeks, which was discontinued at enrolment. Patients with HbA1c 7.5%-10.0% after ≥16 weeks of using Lina (pre-enrolment or during a 16-week, open-label period) and 2 weeks of using placebo (Plc) for Empa/Lina 10/5, plus Lina, were randomized (2:1) to once-daily Empa/Lina 10/5 (n = 182) or Plc/Lina 10/5 (n = 93) for 24 weeks. Patients with HbA1c ≥ 7.0% at Week 24 received Empa/Lina up-titrated to 25/5 (n = 126) or the corresponding placebo (n = 80), per randomization, from Week 28; 172 Empa/Lina and 84 Plc/Lina patients completed 52 weeks. RESULTS: Change from baseline in HbA1c was greater (P < .0001) with Empa/Lina than with Plc/Lina at Week 24 (primary outcome, -0.93% vs 0.21%; adjusted mean difference, -1.14%) and Week 52 (-1.16% vs 0.06%; adjusted mean difference, -1.22%). More patients with HbA1c < 7.0% and greater decreases in fasting plasma glucose, body weight and systolic blood pressure were seen in the Empa/Lina group than in the Plc/Lina group. Empa/Lina was well tolerated. The adverse events that were more frequent with Empa/Lina were known empagliflozin-associated events (eg, increased urination, increased blood ketones). There were no adjudication-confirmed diabetic ketoacidosis events or lower limb amputations. CONCLUSIONS: These results support the notion that empagliflozin-linagliptin in fixed-dose combination is a therapeutic option for Japanese patients with type 2 diabetes.


Subject(s)
Benzhydryl Compounds/administration & dosage , Diabetes Mellitus, Type 2/drug therapy , Glucosides/administration & dosage , Hypoglycemic Agents/administration & dosage , Linagliptin/administration & dosage , Aged , Blood Glucose/drug effects , Body Weight/drug effects , Diabetes Mellitus, Type 2/blood , Double-Blind Method , Drug Therapy, Combination , Female , Glycated Hemoglobin/drug effects , Humans , Male , Middle Aged , Treatment Outcome
8.
Neuroimage ; 162: 1-12, 2017 11 15.
Article in English | MEDLINE | ID: mdl-28844890

ABSTRACT

The hypothalamus consists of numerous nuclei, and is regarded as the highest center for various autonomic functions. Although each hypothalamic nucleus implements a distinct function, it remains difficult to investigate the human hypothalamus at the nucleus level. In the present high-resolution functional MRI study, we utilized areal parcellation to discriminate individual nuclei in the human hypothalamus based on areal profiles of resting-state functional connectivity. The areal parcellation detected ten foci that were expected to represent hypothalamic nuclei, and the locations of the foci were consistent with those of the hypothalamic nuclei identified in previous histological studies. Regions of interest (ROI) analyses revealed contrasting brain activity changes following glucose ingestion: decrease in the ventromedial hypothalamic nucleus and increase in the lateral hypothalamic area in parallel with blood glucose increase. Moreover, decreased brain activity in the arcuate nucleus predicted future elevation of blood insulin during the first 10 min after glucose ingestion. These results suggest that the hypothalamic nuclei can putatively be determined using areal parcellation, and that the ROI analysis of the human hypothalamic nuclei is useful for future scientific and clinical investigations into the autonomic functions.


Subject(s)
Glucose/metabolism , Hypothalamus/diagnostic imaging , Hypothalamus/metabolism , Magnetic Resonance Imaging/methods , Neuroimaging/methods , Adult , Female , Humans , Image Processing, Computer-Assisted , Male , Young Adult
9.
Heart Vessels ; 32(2): 166-174, 2017 Feb.
Article in English | MEDLINE | ID: mdl-27142065

ABSTRACT

Proton magnetic resonance spectroscopy (1H-MRS) enables the assessment of myocardial triglyceride (TG) content, which is reported to be associated with cardiac dysfunction and morphology accompanied by metabolic disorder and cardiac hemodynamic status. The clinical usefulness of myocardial TG content measurements in patients with left ventricular hypertrophy (LVH) has not been fully investigated. We examined whether myocardial TG content assessed by 1H-MRS was useful for diagnosis in patients with LVH. To quantify myocardial TG content, we conducted 1H-MRS in 35 subjects with LVH. Left ventricular function was measured by cardiac magnetic resonance imaging. Patients were assigned to a hypertensive heart disease (HHD, n = 10) or hypertrophic cardiomyopathy (HCM, n = 25) group based on the histology and/or late gadolinium enhancement pattern. The myocardial TG content was significantly higher in the HHD group than in the HCM group (2.14 ± 1.29 vs. 1.09 ± 0.72 %, P < 0.001). Myocardial TG content were significantly and negatively correlated with LV mass (r = -0.41, P < 0.04) and stroke volume (r = -0.64, P < 0.05) in the HCM group and HHD group, respectively. In a multivariate analysis, LV mass volume and diagnosis of HCM or HHD were independent factors of the myocardial TG content. The results suggest that myocardial metabolism may differ between HCM and HHD patients and that measurement of myocardial TG content by 1H-MRS may be useful for evaluating the myocardial metabolic features of LVH.


Subject(s)
Cardiomyopathy, Hypertrophic/physiopathology , Hypertension/physiopathology , Hypertrophy, Left Ventricular/diagnostic imaging , Myocardium/chemistry , Triglycerides/analysis , Adult , Aged , Cardiomyopathy, Hypertrophic/complications , Cross-Sectional Studies , Echocardiography , Female , Gadolinium/chemistry , Humans , Hypertension/complications , Japan , Linear Models , Male , Middle Aged , Proton Magnetic Resonance Spectroscopy , Stroke Volume , Ventricular Function, Left
10.
J Clin Lab Anal ; 31(1)2017 Jan.
Article in English | MEDLINE | ID: mdl-27386821

ABSTRACT

BACKGROUND: Glycated albumin (GA) reflects shorter-term glycemic control than HbA1c. We have reported that HbA1c is paradoxically increased in diabetic patients whose glycemic control deteriorated before ameliorating. In this study, we analyzed paradoxical increases of glycemic control indicators after treatment in patients with fulminant type 1 diabetes (FT1D). We also investigated whether the GA/HbA1c ratio may reflect shorter-term glycemic control than GA. METHODS: Five FT1D patients whose post-treatment HbA1c and GA levels were measured were enrolled. We also used a formula to estimate HbA1c and GA from the fictitious models of changes in plasma glucose in FT1D patients. In this model, the periods during which HbA1c, GA, and the GA/HbA1c ratio were higher than at the first visit were compared. In addition, the half-life for the GA/HbA1c ratio was calculated in accordance with the half-lives for HbA1c and GA (36 and 14 days, respectively). RESULTS: In all FT1D patients, HbA1c levels 2-4 weeks after treatment were increased, with three patients (60%) experiencing an increase of GA levels. In contrast, an increase of the GA/HbA1c ratio was observed in only one patient. In all of the different models of changes in plasma glucose in FT1D patients, the length of time during which the values were higher than at the first visit was in the order of HbA1c > GA > GA/HbA1c ratio. The half-life for the GA/HbA1c ratio was 9 days, shorter than GA. CONCLUSIONS: These findings suggest that the GA/HbA1c ratio reflects shorter-term glycemic control than GA.


Subject(s)
Diabetes Mellitus, Type 1/blood , Glycated Hemoglobin/analysis , Hyperglycemia/blood , Serum Albumin/analysis , Adult , Aged , Blood Glucose/analysis , Glycation End Products, Advanced , Half-Life , Humans , Middle Aged , Models, Biological , Glycated Serum Albumin
11.
Nat Genet ; 40(9): 1098-102, 2008 Sep.
Article in English | MEDLINE | ID: mdl-18711366

ABSTRACT

We conducted a genome-wide association study using 207,097 SNP markers in Japanese individuals with type 2 diabetes and unrelated controls, and identified KCNQ1 (potassium voltage-gated channel, KQT-like subfamily, member 1) to be a strong candidate for conferring susceptibility to type 2 diabetes. We detected consistent association of a SNP in KCNQ1 (rs2283228) with the disease in several independent case-control studies (additive model P = 3.1 x 10(-12); OR = 1.26, 95% CI = 1.18-1.34). Several other SNPs in the same linkage disequilibrium (LD) block were strongly associated with type 2 diabetes (additive model: rs2237895, P = 7.3 x 10(-9); OR = 1.32, 95% CI = 1.20-1.45, rs2237897, P = 6.8 x 10(-13); OR = 1.41, 95% CI = 1.29-1.55). The association of these SNPs with type 2 diabetes was replicated in samples from Singaporean (additive model: rs2237895, P = 8.5 x 10(-3); OR = 1.14, rs2237897, P = 2.4 x 10(-4); OR = 1.22) and Danish populations (additive model: rs2237895, P = 3.7 x 10(-11); OR = 1.24, rs2237897, P = 1.2 x 10(-4); OR = 1.36).


Subject(s)
Asian People/genetics , KCNQ1 Potassium Channel/genetics , White People/genetics , Case-Control Studies , Diabetes Mellitus, Type 2/genetics , Gene Expression , Genetic Predisposition to Disease , Genome-Wide Association Study , Humans , Polymorphism, Single Nucleotide , Singapore
12.
Am J Physiol Endocrinol Metab ; 310(1): E32-40, 2016 Jan 01.
Article in English | MEDLINE | ID: mdl-26487001

ABSTRACT

The accumulation of intramyocellular lipid (IMCL) is recognized as an important determinant of insulin resistance, and is increased by a high-fat diet (HFD). However, the effects of HFD on IMCL and insulin sensitivity are highly variable. The aim of this study was to identify the genes in muscle that are related to this inter-individual variation. Fifty healthy men were recruited for this study. Before and after HFD for 3 days, IMCL levels in the tibialis anterior were measured by (1)H magnetic resonance spectroscopy, and peripheral insulin sensitivity was evaluated by glucose infusion rate (GIR) during the euglycemic-hyperinsulinemic clamp. Subjects who showed a large increase in IMCL and a large decrease in GIR by HFD were classified as high responders (HRs), and subjects who showed a small increase in IMCL and a small decrease in GIR were classified as low responders (LRs). In five subjects from each group, the gene expression profile of the vastus lateralis muscle was analyzed by DNA microarray analysis. Before HFD, gene expression profiles related to lipid metabolism were comparable between the two groups. Gene Set Enrichment Analysis demonstrated that five gene sets related to lipid metabolism were upregulated by HFD in the HR group but not in the LR group. Changes in gene expression patterns were confirmed by qRT-PCR using more samples (LR, n = 9; HR, n = 11). These results suggest that IMCL accumulation/impaired insulin sensitivity after HFD is closely associated with changes in the expression of genes related to lipid metabolism in muscle.


Subject(s)
Diet, High-Fat , Insulin Resistance/genetics , Lipid Metabolism/genetics , Muscle Fibers, Skeletal/metabolism , Adult , DNA Copy Number Variations/drug effects , DNA, Mitochondrial/genetics , Dietary Fats/administration & dosage , Gene Expression Profiling , Humans , Lipid Metabolism/drug effects , Male , Muscle Fibers, Skeletal/drug effects , Muscle, Skeletal/drug effects , Muscle, Skeletal/metabolism , Oligonucleotide Array Sequence Analysis , Young Adult
13.
Hum Mol Genet ; 23(1): 239-46, 2014 Jan 01.
Article in English | MEDLINE | ID: mdl-23945395

ABSTRACT

Although over 60 loci for type 2 diabetes (T2D) have been identified, there still remains a large genetic component to be clarified. To explore unidentified loci for T2D, we performed a genome-wide association study (GWAS) of 6 209 637 single-nucleotide polymorphisms (SNPs), which were directly genotyped or imputed using East Asian references from the 1000 Genomes Project (June 2011 release) in 5976 Japanese patients with T2D and 20 829 nondiabetic individuals. Nineteen unreported loci were selected and taken forward to follow-up analyses. Combined discovery and follow-up analyses (30 392 cases and 34 814 controls) identified three new loci with genome-wide significance, which were MIR129-LEP [rs791595; risk allele = A; risk allele frequency (RAF) = 0.080; P = 2.55 × 10(-13); odds ratio (OR) = 1.17], GPSM1 [rs11787792; risk allele = A; RAF = 0.874; P = 1.74 × 10(-10); OR = 1.15] and SLC16A13 (rs312457; risk allele = G; RAF = 0.078; P = 7.69 × 10(-13); OR = 1.20). This study demonstrates that GWASs based on the imputation of genotypes using modern reference haplotypes such as that from the 1000 Genomes Project data can assist in identification of new loci for common diseases.


Subject(s)
Diabetes Mellitus, Type 2/genetics , Genome-Wide Association Study , Guanine Nucleotide Dissociation Inhibitors/genetics , Monocarboxylic Acid Transporters/genetics , Genetic Loci , Genetic Predisposition to Disease , Genetic Variation , Genome, Human , Haplotypes , Humans , Leptin/genetics , MicroRNAs/genetics , Polymorphism, Single Nucleotide
14.
Biochem Biophys Res Commun ; 473(4): 947-952, 2016 05 13.
Article in English | MEDLINE | ID: mdl-27040770

ABSTRACT

A single bout of exercise is known to increase the insulin sensitivity of skeletal muscle; however, the underlying mechanism of this phenomenon is not fully understood. Because a single bout of exercise induces a transient increase in blood interleukin-6 (IL-6) level, we hypothesized that the enhancement of insulin sensitivity after a single bout of exercise in skeletal muscle is mediated at least in part through IL-6-dependent mechanisms. To test this hypothesis, C57BL6J mice were intravenously injected with normal IgG or an IL-6 neutralizing antibody before exercise. Twenty-four hours after a single bout of exercise, the plantaris muscle was harvested to measure insulin sensitivity and glucose transporter (GLUT)-4 expression levels by ex-vivo insulin-stimulated 2-deoxyglucose (2-DG) uptake and Western blotting, respectively. Compared with sedentary mice, mice that performed exercise showed enhanced IL-6 concentration, insulin-stimulated 2-DG uptake, and GLUT-4 expression in the plantaris muscle. The enhanced insulin sensitivity and GLUT4 expression were canceled by injection of the IL-6 neutralizing antibody before exercise. In addition, IL-6 injection increased GLUT4 expression, both in the plantaris muscle and the soleus muscle in C57BL6J mice. Furthermore, a short period of incubation with IL-6 increased GLUT4 expression in differentiated C2C12 myotubes. In summary, these results suggested that IL-6 increased GLUT4 expression in muscle and that this phenomenon may play a role in the post-exercise enhancement of insulin sensitivity in skeletal muscle.


Subject(s)
Glucose Transporter Type 4/metabolism , Insulin/pharmacology , Interleukin-6/physiology , Muscle, Skeletal/metabolism , Physical Conditioning, Animal , Animals , Cells, Cultured , Interleukin-6/antagonists & inhibitors , Interleukin-6/blood , Male , Mice , Mice, Inbred C57BL , Muscle, Skeletal/drug effects , Muscle, Skeletal/enzymology , Proto-Oncogene Proteins c-akt/metabolism
15.
Nihon Rinsho ; 73(3): 363-72, 2015 Mar.
Article in Japanese | MEDLINE | ID: mdl-25812360

ABSTRACT

Type 2 diabetes mellitus (T2DM) is widely accepted as the progressive disease. It is natural to think, if the newly diagnosed patient does not change the life-style habits and does not receive any medications, the state of T2DM will become more seriously. However, in this article, how to arrest the natural history of T2DM will be discussed by summarizing the recent findings on this topic. Those are; autophagy of pancreatic ß cell: a sweet process to diabetes, hyperglycemia-induced oxidative stress on ß cell function, zinc, insulin and the liver, and so on. In short, the important things are; people should know the reasons why minor abnormalities have happened, and the practitioners have to try hard to remove such causes triggering T2DM.


Subject(s)
Diabetes Mellitus, Type 2/physiopathology , Blood Glucose/metabolism , Glucose Tolerance Test , Humans , Insulin/metabolism , Insulin Secretion , Insulin-Secreting Cells/pathology
16.
Hum Mol Genet ; 21(13): 3042-9, 2012 Jul 01.
Article in English | MEDLINE | ID: mdl-22456796

ABSTRACT

To identify a novel susceptibility locus for type 2 diabetes, we performed an imputation-based, genome-wide association study (GWAS) in a Japanese population using newly obtained imputed-genotype data for 2 229 890 single-nucleotide polymorphisms (SNPs) estimated from previously reported, directly genotyped GWAS data in the same samples (stage 1: 4470 type 2 diabetes versus 3071 controls). We directly genotyped 43 new SNPs with P-values of <10(-4) in a part of stage-1 samples (2692 type 2 diabetes versus 3071 controls), and the associations of validated SNPs were evaluated in another 11 139 Japanese individuals (stage 2: 7605 type 2 diabetes versus 3534 controls). Combined meta-analysis using directly genotyped data for stages 1 and 2 revealed that rs515071 in ANK1 and rs7656416 near MGC21675 were associated with type 2 diabetes in the Japanese population at the genome-wide significant level (P < 5 × 10(-8)). The association of rs515071 was also observed in European GWAS data (combined P for all populations = 6.14 × 10(-10)). Rs7656416 was in linkage disequilibrium to rs6815464, which had recently been identified as a top signal in a meta-analysis of East Asian GWAS for type 2 diabetes (r(2) = 0.76 in stage 2). The association of rs7656416 with type 2 diabetes disappeared after conditioning on rs6815464. These results indicate that the ANK1 locus is a new, common susceptibility locus for type 2 diabetes across different ethnic groups. The signal of association was weaker in the directly genotyped data, so the improvement in signal indicates the importance of imputation in this particular case.


Subject(s)
Ankyrins/genetics , Asian People/genetics , Diabetes Mellitus, Type 2/ethnology , Diabetes Mellitus, Type 2/genetics , Polymorphism, Single Nucleotide , Cells, Cultured , Genetic Predisposition to Disease , Genome-Wide Association Study , Genotype , Humans , Japan
17.
Clin Exp Hypertens ; 36(4): 236-43, 2014.
Article in English | MEDLINE | ID: mdl-23865387

ABSTRACT

To identify risk factors for cardiovascular disease (CVD) in hypertensive patients with no history of CVD being treated with antihypertensive drugs, we examined subgroup data (n = 13 052) from the prospective, observational Olmesartan Mega Study to Determine the Relationship between Cardiovascular Endpoints and Blood Pressure Goal Achievement (OMEGA) study. Risk factors for CVD, stroke and coronary heart disease (CHD) were examined using a Cox proportional hazards model. In addition, the effect of statin therapy at baseline on CHD prevention was analyzed in dyslipidemic patients. The factors significantly related to CVD were female (hazard ratio [HR] = 0.637, 95% confidence interval [CI] 0.428-0.948), older age (65-69 years: HR = 2.165, 95% CI 1.214-3.861; 70-74 years: HR = 2.324, 95% CI 1.294-4.174; ≥75 years: HR = 2.448, 95% CI 1.309-4.578), family history of CHD (HR = 1.993, 95% CI 1.249-3.179), diabetes (HR = 2.287, 95% CI 1.700-3.078), current smoking (HR = 2.289, 95% CI 1.512-3.466) and alcohol drinking socially (HR = 0.589, 95% CI 0.379-0.913). Diabetes was a risk factor for both stroke and CHD, while age, family history of CHD, and sodium intake score were risk factors for stroke alone. Sex, dyslipidemia, smoking and exercise habits were risk factors for CHD alone. The risk of CHD in dyslipidemic patients on statin treatment was comparable to the risk in patients without dyslipidemia (HR = 1.134, 95% CI 0.604-2.126). However, in dyslipidemic patients not on statin treatment, the HR increased to 1.807 (95% CI 1.156-2.825). In conclusion, some risk factors for CVD in hypertensive patients being treated with antihypertensive drugs with no history of CVD differed between CHD and stroke. These results suggest the importance of managing dyslipidemia with a statin for primary prevention of CHD, as well as the importance of hypertension therapy.


Subject(s)
Cardiovascular Diseases/prevention & control , Hypolipidemic Agents/therapeutic use , Imidazoles/therapeutic use , Lipids/blood , Primary Prevention/methods , Risk Assessment/methods , Tetrazoles/therapeutic use , Aged , Angiotensin II Type 1 Receptor Blockers/therapeutic use , Cardiovascular Diseases/blood , Cardiovascular Diseases/epidemiology , Female , Follow-Up Studies , Humans , Japan/epidemiology , Male , Middle Aged , Retrospective Studies , Risk Factors , Treatment Outcome
18.
Int Heart J ; 55(2): 146-52, 2014.
Article in English | MEDLINE | ID: mdl-24632963

ABSTRACT

Carotid intima-media thickness (IMT), a measure of atherosclerosis, is modulated by multiple risk factors. Accordingly, comprehensive control of risk factors is indispensable for management of atherosclerosis. In this study, as a posthoc analysis of the JART Study we planned two analyses. In the main analysis, we evaluated the effect of intensive lipid-lowering therapy with rosuvastatin on carotid IMT in high-risk patients. We also evaluated efficacy in the presence or absence of each risk factor using the full analysis population in the JART Study. Patients with low-density lipoprotein cholesterol (LDL-C) ≥ 140 mg/dL and max-IMT ≥ 1.1 mm were randomized to rosuvastatin or pravastatin therapy for 12 months. Dosages were allowed to increase to 10 mg/day and 20 mg/day to achieve LDL-goals (aggressive goals for rosuvastatin group and guideline goals for pravastatin group). For the main analysis, we assessed 200 high-risk patients (105 in the rosuvastatin group), as category III or secondary prevention according to the Japan Atherosclerosis Society guideline 2007, whereas we assessed 289 patients in the other analysis. Rosuvastatin significantly slowed the percentage change in mean-IMT at 12 months compared with pravastatin (1.40 ± 10.03% versus 6.43 ± 13.77%, P = 0.005). LDL-C was reduced by 48.1% in the rosuvastatin group and 27.9% in the pravastatin group. The rate of achieving the LDL-C goal was significantly greater in the rosuvastatin group compared with the pravastatin group (P < 0.001). Rosuvastatin slowed the change in mean-IMT in the presence of every risk factor. Thus, intensive lipid-lowering therapy reduced progression of carotid IMT in high-risk patients.


Subject(s)
Atherosclerosis/diagnostic imaging , Carotid Intima-Media Thickness , Lipids/blood , Pravastatin/administration & dosage , Aged , Anticholesteremic Agents/administration & dosage , Atherosclerosis/blood , Atherosclerosis/drug therapy , Cholesterol, LDL/blood , Cholesterol, LDL/drug effects , Disease Progression , Dose-Response Relationship, Drug , Double-Blind Method , Female , Fluorobenzenes/administration & dosage , Follow-Up Studies , Humans , Male , Middle Aged , Prospective Studies , Pyrimidines/administration & dosage , Risk Factors , Rosuvastatin Calcium , Sulfonamides/administration & dosage , Treatment Outcome
19.
Diabetes Ther ; 2024 Sep 30.
Article in English | MEDLINE | ID: mdl-39347897

ABSTRACT

INTRODUCTION: Imeglimin is a first-in-class, novel, oral glucose-lowering agent for the treatment of type 2 diabetes mellitus. The efficacy and safety of imeglimin as an antidiabetic agent have been investigated in clinical trials. However, its metabolic effects in humans have not yet been fully elucidated. METHODS: The Study to InveStIgate the Metabolic Action of Imeglimin on patients with type 2 diabetes mellitus (SISIMAI) is a single-arm intervention study. In this study, we have recruited 25 patients with type 2 diabetes to receive 2000 mg/day imeglimin for 20 weeks. We perform a 75-g oral glucose tolerance test (OGTT) with double-glucose tracers, a two-step hyperinsulinemic-euglycemic clamp with glucose tracer, ectopic fat measurement by proton magnetic resonance spectroscopy, visceral/subcutaneous fat area measurement by magnetic resonance imaging, muscle biopsy, and evaluation of fitness level by cycle ergometer before and after imeglimin administration. PLANNED OUTCOMES: The primary outcome is the change in area under the curve of glucose levels during the OGTT after 20 weeks of imeglimin treatment. We also calculate the endogenous glucose production, rate of oral glucose appearance, and rate of glucose disappearance from the data during the 75-g OGTT and compare them between pre- and post-treatment. Additionally, we will compare other parameters, such as the changes in tissue-specific insulin sensitivity, ectopic fat accumulation, visceral/subcutaneous fat area accumulation, and fitness level between each point. This is the first study to investigate the organ-specific metabolic action of imeglimin in patients with type 2 diabetes mellitus using the 75-g OGTT with the double tracer method. The results of this study are expected to provide useful information for drug selection based on the pathophysiology of individual patients with type 2 diabetes mellitus. TRIAL REGISTRATION: jRCTs031210600.

20.
Front Endocrinol (Lausanne) ; 15: 1390778, 2024.
Article in English | MEDLINE | ID: mdl-39377071

ABSTRACT

Objective: The proportion of young Japanese women who are underweight is exceptionally high. We previously showed that the prevalence of impaired glucose tolerance (IGT) was high in underweight young Japanese women, and that IGT was characterized by high free fatty acid levels and adipose tissue insulin resistance (ATIR). As the next step, this study aimed to explore factors associated with elevated ATIR in this population. Participants: Ninety-eight young, healthy, underweight women participated in this study. Design: To investigate the relationship between ATIR and metabolic parameters, participants were divided into three groups (Low, Medium, and High) according to ATIR level. Body composition examination, oral glucose tolerance testing, and blood biochemical analysis were performed; Adipo-IR and the Matsuda index were used as indices of ATIR and systemic insulin sensitivity, respectively. Results: Participants in the High ATIR group had the highest prevalence of IGT (25%), and significantly higher body fat percentage, whole-body insulin resistance, and levels of insulin-like growth factor-1 and dehydroepiandrosterone sulfate (DHEA-S) than the other two groups. They were also significantly younger and had higher systolic blood pressure than the Low ATIR group. Multiple regression analysis showed that DHEA-S, which is known to enhance lipolysis in adipose tissue, was an independent correlate of ATIR. Conclusions: Underweight Japanese women with high ATIR had impaired metabolism, a higher prevalence of IGT, higher systemic insulin resistance, and higher systolic blood pressure. DHEA-S was a determinant of high ATIR levels.


Subject(s)
Adipose Tissue , Dehydroepiandrosterone Sulfate , Insulin Resistance , Humans , Female , Dehydroepiandrosterone Sulfate/blood , Dehydroepiandrosterone Sulfate/metabolism , Adult , Japan/epidemiology , Young Adult , Adipose Tissue/metabolism , Glucose Intolerance/metabolism , Glucose Intolerance/epidemiology , Thinness/metabolism , Thinness/epidemiology , Body Composition , Glucose Tolerance Test , Blood Glucose/metabolism , Blood Glucose/analysis , East Asian People
SELECTION OF CITATIONS
SEARCH DETAIL