Interaction Between Type 2 Diabetes Prevention Strategies and Genetic Determinants of Coronary Artery Disease on Cardiometabolic Risk Factors

Coronary artery disease (CAD) is more frequent among individuals with dysglycemia. Preventive interventions for diabetes can improve cardiometabolic risk factors (CRFs), but it is unclear whether the benefits on CRFs are similar for individuals at different genetic risk for CAD. We built a 201-variant polygenic risk score (PRS) for CAD and tested for interaction with diabetes prevention strategies on 1-year changes in CRFs in 2,658 Diabetes Prevention Program (DPP) participants. We also examined whether separate lifestyle behaviors interact with PRS and affect changes in CRFs in each intervention group. Participants in both the lifestyle and metformin interventions had greater improvement in the majority of recognized CRFs compared with placebo (P < 0.001) irrespective of CAD genetic risk (P interaction > 0.05). We detected nominal significant interactions between PRS and dietary quality and physical activity on 1-year change in BMI, fasting glucose, triglycerides, and HDL cholesterol in individuals randomized to metformin or placebo, but none of them achieved the multiple-testing correction for significance. This study confirms that diabetes preventive interventions improve CRFs regardless of CAD genetic risk and delivers hypothesis-generating data on the varying benefit of increasing physical activity and improving diet on intermediate cardiovascular risk factors depending on individual CAD genetic risk profile.

Gene Expression Analysis of the Pre-Diabetic Pancreas to Identify Pathogenic Mechanisms and Biomarkers of Type 1 Diabetes

Type 1 Diabetes (T1D) occurs as a result of the autoimmune destruction of pancreatic β-cells by self-reactive T cells. The etiology of this disease is complex and difficult to study due to a lack of disease-relevant tissues from pre-diabetic individuals. In this study, we performed gene expression analysis on human pancreas tissues obtained from the Network of Pancreatic Organ Donors with Diabetes (nPOD), and showed that 155 genes were differentially expressed by ≥2-fold in the pancreata of autoantibody-positive (AA+) at-risk individuals compared to healthy controls. Only 48 of these genes remained changed by ≥2-fold in the pancreata of established T1D patients. Pathway analysis of these genes showed a significant association with various immune pathways. We were able to validate the differential expression of eight disease-relevant genes by QPCR analysis: A significant upregulation of CADM2, and downregulation of TRPM5, CRH, PDK4, ANGPL4, CLEC4D, RSG16, and FCGR2B was confirmed in the pancreata of AA+ individuals versus controls. Studies have already implicated FCGR2B in the pathogenesis of disease in non-obese diabetic (NOD) mice. Here we showed that CADM2, TRPM5, PDK4, and ANGPL4 were similarly changed in the pancreata of pre-diabetic 12-week-old NOD mice compared to NOD.B10 controls, suggesting a possible role for these genes in the pathogenesis of both T1D and NOD disease. The loss of the leukocyte-specific gene, FCGR2B, in the pancreata of AA+ individuals, is particularly interesting, as it may serve as a potential whole blood biomarker of disease progression. To test this, we quantified FCGR2B expression in peripheral blood samples of T1D patients, and AA+ and AA- first-degree relatives of T1D patients enrolled in the TrialNet Pathway to Prevention study. We showed that FCGR2B was significantly reduced in the peripheral blood of AA+ individuals compared to AA- controls. Together, these findings demonstrate that gene expression analysis of pancreatic tissue and peripheral blood samples can be used to identify disease-relevant genes and pathways and potential biomarkers of disease progression in T1D.

Metallothionein 1 negatively regulates glucose-stimulated insulin secretion and is differentially expressed in conditions of beta cell compensation and failure in mice and humans

AIMS/HYPOTHESIS

The mechanisms responsible for beta cell compensation in obesity and for beta cell failure in type 2 diabetes are poorly defined. The mRNA levels of several metallothionein (MT) genes are upregulated in islets from individuals with type 2 diabetes, but their role in beta cells is not clear. Here we examined: (1) the temporal changes of islet Mt1 and Mt2 gene expression in mouse models of beta cell compensation and failure; and (2) the role of Mt1 and Mt2 in beta cell function and glucose homeostasis in mice.

METHODS

Mt1 and Mt2 expression was assessed in islets from: (1) control lean (chow diet-fed) and diet-induced obese (high-fat diet-fed for 6 weeks) mice; (2) mouse models of diabetes (db/db mice) at 6 weeks old (prediabetes) and 16 weeks old (after diabetes onset) and age-matched db/+ (control) mice; and (3) obese non-diabetic ob/ob mice (16-week-old) and age-matched ob/+ (control) mice. MT1E, MT1X and MT2A expression was assessed in islets from humans with and without type 2 diabetes. Mt1-Mt2 double-knockout (KO) mice, transgenic mice overexpressing Mt1 under the control of its natural promoter (Tg-Mt1) and corresponding control mice were also studied. In MIN6 cells, MT1 and MT2 were inhibited by small interfering RNAs. mRNA levels were assessed by real-time RT-PCR, plasma insulin and islet MT levels by ELISA, glucose tolerance by i.p. glucose tolerance tests and overnight fasting-1 h refeeding tests, insulin tolerance by i.p. insulin tolerance tests, insulin secretion by RIA, cytosolic free Ca²⁺ concentration with Fura-2 leakage resistant (Fura-2 LR), cytosolic free Zn²⁺ concentration with Fluozin-3, and NAD(P)H by autofluorescence.

RESULTS

Mt1 and Mt2 mRNA levels were reduced in islets of murine models of beta cell compensation, whereas they were increased in diabetic db/db mice. In humans, MT1X mRNA levels were significantly upregulated in islets from individuals with type 2 diabetes in comparison with non-diabetic donors, while MT1E and MT2A mRNA levels were unchanged. Ex vivo, islet Mt1 and Mt2 mRNA and MT1 and MT2 protein levels were downregulated after culture with glucose at 10-30 mmol/l vs 2-5 mmol/l, in association with increased insulin secretion. In human islets, mRNA levels of MT1E, MT1X and MT2A were downregulated by stimulation with physiological and supraphysiological levels of glucose. In comparison with wild-type (WT) mice, Mt1-Mt2 double-KO mice displayed improved glucose tolerance in association with increased insulin levels and enhanced insulin release from isolated islets. In contrast, isolated islets from Tg-Mt1 mice displayed impaired glucose-stimulated insulin secretion (GSIS). In both Mt1-Mt2 double-KO and Tg-Mt1 models, the changes in GSIS occurred despite similar islet insulin content, rises in cytosolic free Ca²⁺ concentration and NAD(P)H levels, or intracellular Zn²⁺ concentration vs WT mice. In MIN6 cells, knockdown of MT1 but not MT2 potentiated GSIS, suggesting that Mt1 rather than Mt2 affects beta cell function.

CONCLUSIONS/INTERPRETATION

These findings implicate Mt1 as a negative regulator of insulin secretion. The downregulation of Mt1 is associated with beta cell compensation in obesity, whereas increased Mt1 accompanies beta cell failure and type 2 diabetes.

SNP-Based Genetic Risk Score Modeling Suggests No Increased Genetic Susceptibility of the Roma Population to Type 2 Diabetes Mellitus

BACKGROUND

In a previous survey, an elevated fasting glucose level (FG) and/or known type 2 diabetes mellitus (T2DM) were significantly more frequent in the Roma population than in the Hungarian general population. We assessed whether the distribution of 16 single nucleotide polymorphisms (SNPs) with unequivocal effects on the development of T2DM contributes to this higher prevalence.

METHODS

Genetic risk scores, unweighted (GRS) and weighted (wGRS), were computed and compared between the study populations. Associations between GRSs and FG levels and T2DM status were investigated in separate and combined study populations.

RESULTS

The Hungarian general population carried a greater genetic risk for the development of T2DM (GRS_General = 15.38 ± 2.70 vs. GRS_Roma = 14.80 ± 2.68, p < 0.001; wGRS_General = 1.41 ± 0.32 vs. wGRS_Roma = 1.36 ± 0.31, p < 0.001). In the combined population models, GRSs and wGRSs showed significant associations with elevated FG (p < 0.001) and T2DM (p < 0.001) after adjusting for ethnicity, age, sex, body mass index (BMI), high-density Lipoprotein Cholesterol (HDL-C), and triglyceride (TG). In these models, the effect of ethnicity was relatively strong on both outcomes (FG levels: βethnicity = 0.918, p < 0.001; T2DM status: OR_ethnicity = 2.484, p < 0.001).

CONCLUSIONS

The higher prevalence of elevated FG and/or T2DM among Roma does not seem to be directly linked to their increased genetic load but rather to their environmental/cultural attributes. Interventions targeting T2DM prevention among Roma should focus on harmful environmental exposures related to their unhealthy lifestyle.

Sequencing reveals protective and pathogenic effects on development of diabetes of rare GLIS3 variants

Background

Based on the association of common GLIS3 variants with various forms of diabetes and the biological role of GLIS3 in beta-cells, we sequenced GLIS3 in non-diabetic and diabetic Danes to investigate the effect of rare missense variants on glucose metabolism.

Methods

We sequenced 53 patients with maturity-onset diabetes of the young (MODY), 5,726 non-diabetic participants, 2,930 patients with newly diagnosed type 2 diabetes and 206 patients with glutamic acid decarboxylase antibody (GADA) -positive diabetes.

Results

In total we identified 86 rare (minor allele frequency < 0.1%) missense variants. None was considered causal for the presence of MODY. Among patients with type 2 diabetes, we observed a higher prevalence of rare GLIS3 missense variants (2.5%) compared to non-diabetic individuals (1.8%) (odds ratio of 1.37 (interquartile range:1.01–1.88, p = 0.04)). A significantly increased HbA1c was found among patients with type 2 diabetes and with GADA-positive diabetes carrying rare GLIS3 variants compared to non-carriers of rare GLIS3 variants with diabetes (p = 0.02 and p = 0.004, respectively). One variant (p.I28V) was found to have a minor allele frequency of only 0.03% among patients with type 2 diabetes compared to 0.2% among non-diabetic individuals suggesting a protective function (odds ratio of 0.20 (interquartile range: 0.005–1.4, p = 0.1)), an effect which was supported by publically available data. This variant was also associated with a lower level of fasting plasma glucose among non-diabetic individuals (p = 0.046).

Conclusion

Rare missense variants in GLIS3 associates nominally with increased level of HbA1c and increased risk of developing type 2 diabetes. In contrast, the rare p.I28V variant associate with reduced level of fasting plasma glucose and may be protective against type 2 diabetes.

Reverse GWAS: Using genetics to identify and model phenotypic subtypes

Recent and classical work has revealed biologically and medically significant subtypes in complex diseases and traits. However, relevant subtypes are often unknown, unmeasured, or actively debated, making automated statistical approaches to subtype definition valuable. We propose reverse GWAS (RGWAS) to identify and validate subtypes using genetics and multiple traits: while GWAS seeks the genetic basis of a given trait, RGWAS seeks to define trait subtypes with distinct genetic bases. Unlike existing approaches relying on off-the-shelf clustering methods, RGWAS uses a novel decomposition, MFMR, to model covariates, binary traits, and population structure. We use extensive simulations to show that modelling these features can be crucial for power and calibration. We validate RGWAS in practice by recovering a recently discovered stress subtype in major depression. We then show the utility of RGWAS by identifying three novel subtypes of metabolic traits. We biologically validate these metabolic subtypes with SNP-level tests and a novel polygenic test: the former recover known metabolic GxE SNPs; the latter suggests subtypes may explain substantial missing heritability. Crucially, statins, which are widely prescribed and theorized to increase diabetes risk, have opposing effects on blood glucose across metabolic subtypes, suggesting the subtypes have potential translational value.

High frequency of pathogenic and rare sequence variants in diabetes-related genes among Russian patients with diabetes in pregnancy

AIMS

Diabetes in pregnancy may be associated with monogenic defects of beta-cell function, frequency of which depends on ethnicity, clinical criteria for selection of patients as well as methods used for genetic analysis. The aim was to evaluate the contribution and molecular spectrum of mutations among genes associated with monogenic diabetes in non-obese Russian patients with diabetes in pregnancy using the next-generation sequencing (NGS).

METHODS

188 non-obese pregnant women with diabetes during pregnancy were included in the study; among them 57 subjects (30.3%) met the American Diabetes Association (ADA) criteria of preexisting pregestational diabetes (pre-GDM), whereas 131 women (69.7%) fulfilled criteria of gestational diabetes mellitus (GDM). A custom NGS panel targeting 28 diabetes causative genes was used for sequencing. The sequence variants were rated according to the American College of Medical Genetics and Genomics (ACMG) guidelines.

RESULTS

In total, 23 pathogenic, 18 likely pathogenic and 16 variants of uncertain significance were identified in 59/188 patients (31.4%). The majority of variants (38/59) were found in GCK gene. No significant differences in the number of variants among the two study groups (pre-GDM and GDM) were observed.

CONCLUSIONS

The study suggests that frequency of monogenic variants of diabetes might be underestimated, which warrants a broader use of genetic testing, especially in pregnancy.

Association of Adiponectin and rs1501299 of the ADIPOQ Gene with Prediabetes in Jordan

Type 2 diabetes mellitus (T2DM) is a worldwide health problem caused by resistance to insulin action. This chronic debilitating diseaseis preceded by a stage, known as prediabetes, in which a healthy lifestyle can delay the disease. The discovery of biochemical changes in prediabetes is important to identify individuals at risk of developing T2DM and in explaining disease pathogenesis. Adiponectin is secreted by fat cells and is linked with insulin resistance. Adiponectin levels are dysregulated in prediabetic subjects. This relationship had not been tested in Jordan. We recruited 130 subjects with prediabetes and 130 control subjects. We measured serum levels of adiponectin and genotyped subjects for three single nucleotide polymorphisms (SNPs) in the ADIPOQ gene; rs266729, rs1501299 and rs2241766. In multivariate analysis, we found that serum adiponectin lowers the risk of prediabetes (p = 0.002; odds ratio (OR), 0.764; 95% confidence interval (CI), 0.646⁻0.905). The rs1501299 SNP of the ADIPOQ gene was associated with prediabetes in our population (p = 0.041). Specifically, in multivariate analysis, the GT genotype of rs1501299 increased the risk of prediabetes (p = 0.010; OR, 2.350; 95% CI, 1.231⁻4.486) as well as the TT genotype (p = 0.006; OR, 4.774; 95% CI, 1.551⁻14.693). Our findings indicate that serum adiponectin and SNPs in the ADIPOQ gene are associated with prediabetes in Jordan.

Genetic susceptibility to pre diabetes mellitus and related association with obesity and physical fitness components in Mexican-Mestizos

Pre diabetes mellitus (pre-DM) is considered an early-reversible condition that can progress to Type 2 diabetes mellitus (T2DM) which is the main cause of death for adult Mexican population. Gene variants influencing fasting glucose levels may constitute helpful tool for prevention purposes in pre-DM condition. Physically active Mexican-Mestizo adults (n=565) were genotyped for 6 single nucleotide polymorphisms (SNPs) (ADIPOQ rs2241766, ACSL1 rs9997745, LIPC rs1800588, PPARA rs1800206, PPARG rs1801282 and PPARGC1A rs8192678) related to lipid and carbohydrate metabolism. Fasting glucose was measured and values classified as pre-DM (≥100mg/dL) or normal fasting glucose. Logistic models were used to test associations between pre-DM condition and SNPs, and interaction with Body Mass Index (BMI) and physical fitness components. The A allele of ASCL1 rs9997745 conferred increased risk (OR=3.39, p=0.001) of pre-DM which is modulated by BMI. The A allele of the PPARGC1A rs8192678 showed significant SNP*BMI (OR=1.10, p=0.008) interaction effect for pre-DM risk, meaning that obese subjects showed higher pre-DM risk but normal weight subjects showed lower risk. The effect increased with age and was attenuated by higher cardiorespiratory values. We found that both ACSL1 rs9997745 and PPARGC1A rs8192678 are associated with pre-DM, and that BMI significantly modified their association.

Circulating microRNAs -192 and -194 are associated with the presence and incidence of diabetes mellitus

We sought to identify circulating microRNAs as biomarkers of prevalent or incident diabetes. In a pilot study of 18 sex- and age-matched patients with metabolic syndrome, nine of whom developed diabetes during 6 years of follow-up, an array of 372 microRNAs discovered significantly elevated serum levels of microRNAs -122, -192, -194, and -215 in patients who developed diabetes mellitus type 2 (T2DM). In two cross-sectional validation studies, one encompassing sex- and age-matched groups of patients with T2DM, impaired fasting glucose (IFG) and euglycemic controls (n = 43 each) and the other 53 patients with type 1 diabetes and 54 age- and BMI-matched euglycemic controls, serum levels of miR-192, miR-194, and mi215 were significantly higher in diabetic subjects than in probands with euglycemia or IFG. In a longitudinal study of 213 initially diabetes-free patients of whom 35 developed diabetes during 6 years of follow-up, elevated serum levels of microRNAs 192 and 194 were associated with incident T2DM, independently of fasting glucose, HbA1c and other risk factors. Serum levels of miR-192 and miR-194 were also elevated in diabetic Akt2 knockout mice compared to wild type mice. In conclusion, circulating microRNAs -192 and -194 are potential biomarkers for risk of diabetes.

Gene Expression of Endocannabinoid System Components in Skeletal Muscle and Adipose Tissue of South Asians and White Caucasians with Overweight

OBJECTIVE

The study aimed to investigate whether markers of endocannabinoid signaling differed between men with overweight of South Asian and white Caucasian descent.

METHODS

We included South Asian (n = 10) and white Caucasian (n = 10) men with overweight and prediabetes aged 35 to 50 years. Plasma samples were analyzed for endocannabinoids, their congeners, and lipids. In white adipose tissue (WAT) and skeletal muscle biopsies, mRNA expression of genes involved in the endocannabinoid system (ECS) was assessed using quantitative reverse-transcription polymerase chain reaction (qRT-PCR). Fasting lipid oxidation and glucose oxidation were determined with indirect calorimetry.

RESULTS

Compared to white Caucasians, South Asians had higher levels of plasma 2-linoleoyl glycerol (P < 0.01) and N-linoleoylethanolamine (P < 0.05). Interestingly, in skeletal muscle of South Asians, expression of cannabinoid receptors CB₁ and CB₂ was 10-fold lower (P < 0.001) and that of the endocannabinoid degradation enzyme fatty acid amide hydrolase 2 (FAAH2) was 5-fold lower (P < 0.001) compared to white Caucasians. Expression of genes involved in the ECS in WAT were not different between the two ethnicities. After pooling of both ethnicities, plasma 2-arachidonoylglycerol (2-AG) positively correlated with plasma triglycerides (R = 0.77, P < 0.001) and lipid oxidation (R = 0.55, P < 0.05).

CONCLUSIONS

South Asian men with overweight have higher plasma 2-linoleoyl glycerol and N-linoleoylethanolamine levels and lower expression of CB receptors and the endocannabinoid degradation enzyme FAAH2 in skeletal muscle compared to white Caucasians.

Prevention and Treatment of Type 2 Diabetes: A Pathophysiological-Based Approach

Prediabetes affects approximately 40% of American adults. Randomized trials report that a proportion of individuals with prediabetes develop diabetes despite caloric restriction, physical activity, and/or when treated with metformin, the first-line medication for patients with type 2 diabetes mellitus (T2DM). Currently, there are no valid predictors of the effectiveness of these measures in determining who will and who will not progress to the T2DM state. Few studies have examined the clinical and phenotypic predictors of better and worse glycemic response to lifestyle interventions and metformin in prediabetes and diabetes. Further studies incorporating 'omic' approaches to discover novel markers of phenotypes and treatment effectiveness may pave the way to personalizing the treatment of prediabetes and diabetes.

Statin-induced myopathy SLCO1B1 521T > C is associated with prediabetes, high body mass index and normal lipid profile in Emirati population

BACKGROUND

Statin-induced myopathy has been linked to the C allele of a single nucleotide polymorphism (SNP) (rs4149056) of SLCO1B1 gene. This effect is more significant, but not restricted to simvastatin. Many studies have included European, American, African and Southeast Asian ancestries, but few were carried out on Middle Eastern population.

AIM

To detect the prevalence of SLCO1B1 rs4149056 (521T > C) in Emirati population.

METHOD

We recruited 282 Emiratis through the UAE National Diabetes and Lifestyle Project. Ethical approval was obtained before the study starts. Besides basic data collection, venous blood samples were collected. Fasting blood glucose, Lipid profile, and insulin levels were measured. Genotyping for rs4149056 (521T > C) was tested in triplicates through Real Time-PCR using TaqMan® Drug Metabolism Genotyping Assay. rs2306283 (388A > G) was analyzed for comparison. In addition, presence of minor alleles of both SNPs define stronger association with statin-induced myopathy.

RESULTS

The study included 282 individuals, 52.8% were males with median age of 39.5 years. 10% had Diabetes Mellitus and 23% were hypertensive. Median of body mass index (BMI) was 27.68 kg/m² in males and 28.38 kg/m² in females. One-hundred ninety-seven (69.9%) showed abnormal lipid profile (either increased LDL-cholesterol or triglycerides or both). For rs4149056, C allele was present in 21.3% (2.8% homozygous C and 18.4% heterozygous CT). Although homozygous C genotype prevalence was low, compared with Caucasians (4%) and Africans (0%), C allele was associated with a trend of having higher BMI and abnormal lipid profile. C allele subjects were all pre-diabetics with mean glycated hemoglobin above 6%. Mean BMI in CC, CT, and TT genotypes was 30.91 ± 4.4, 29.48 ± 4.2, 27.96 ± 5.5 kg/m² respectively, with lack of such a trend observed with the different genotypes of the rs2306283 (used for comparison). Abnormal lipid profile was observed in 7/8(87.5%), 38/52(73.1%) and 152/222(70%) of the CC, CT, and TT genotypes respectively.

CONCLUSION

There is lower prevalence of statin-induced myopathy-linked C allele of rs4149056 in SLCO1B1 gene in Emirati population, compared to Caucasians and Africans. However, there is a trend of higher glycosylated hemoglobin and BMI associated with normal lipid profile in patients having this allele.

Loss of B-Cell Anergy in Type 1 Diabetes Is Associated With High-Risk HLA and Non-HLA Disease Susceptibility Alleles

Although B cells reactive with islet autoantigens are silenced by tolerance mechanisms in healthy individuals, they can become activated and contribute to the development of type 1 diabetes. We previously demonstrated that high-affinity insulin-binding B cells (IBCs) occur exclusively in the anergic (B_ND) compartment in peripheral blood of healthy subjects. Consistent with their activation early in disease development, high-affinity IBCs are absent from the B_ND compartment of some first-degree relatives (FDRs) as well as all patients with autoantibody-positive prediabetes and new-onset type 1 diabetes, a time when they are found in pancreatic islets. Loss of B_ND IBCs is associated with a loss of the entire B_ND B-cell compartment consistent with provocation by an environmental trigger or predisposing genetic factors. To investigate potential mechanisms operative in subversion of B-cell tolerance, we explored associations between HLA and non-HLA type 1 diabetes-associated risk allele genotypes and loss of B_NDs in FDRs. We found that high-risk HLA alleles and a subset of non-HLA risk alleles (i.e., PTPN2 [rs1893217], INS [rs689], and IKZF3 [rs2872507]), relevant to B- and T-cell development and function are associated with loss of anergy. Hence, the results suggest a role for risk-conferring alleles in perturbation of B-cell anergy during development of type 1 diabetes.

[Effects of exercise intervention on the relationship between KCNJ11 gene polymorphism and glucose and lipid metabolism in pre-diabetes mellitus]

OBJECTIVE

To investigate the effect of exercise intervention on the relationship between KCNJ11 gene polymorphism and glycolipid metabolism in pre-diabetic population.

METHODS

From January 2017 to March 2017, 5 communities were selected by stratified cluster random sampling method in Liaocheng City, Shandong Province, and 46 cases of pre-diabetes'data were collected through public welfare physical examination activities. The exercise intervention was performed for 8 weeks with their consent and cooperation. The polymorphism of KCNJ11 gene and the index of glucose and lipid metabolism were detected before and after exercise intervention, and the correlation between them was also discussed.

RESULTS

After 8 weeks of exercise intervention, 2 h postprandial blood glucose, fasting glucose, glycosylated hemoglobin and four indicators of blood lipids were significantly improved in pre-diabetes populations(P<0. 05). KCNJ11 gene polymorphism analysis showed that the TG, TC and HDL-C lipid metabolism indexes of CC genotype in rs5219 locus were more significant than those of TT and CT genotypes(t=2. 635, 3. 213 and 2. 048, P=0. 012, 0. 003 and 0. 048)after exercise intervention, the changes of FPG and HbA lc glucose metabolism indexes in GG genotype population of rs2285676 locus were more significant than those in AA and AG genotypes(t=2. 236 and 2. 062, P=0. 034 and 0. 049).

CONCLUSION

The CC genotype of the KCNJ11 gene rs5219 site and the GG genotype of rs2285676 site can be used as the dominant gene to evaluate the change of glucose lipid metabolism in the early stage of diabetes intervention.

Prediabetes is associated with genetic variations in the gene encoding the Kir6.2 subunit of the pancreatic ATP-sensitive potassium channel (KCNJ11): A case-control study in a Han Chinese youth population

BACKGROUND

The E23K variant of the potassium voltage-gated channel subfamily J member 11 (KCNJ11) gene has been reported to be associated with type 2 diabetes (T2D) in many populations. However, little is known about the role of E23K in the development of prediabetes in Chinese youth.

METHODS

To investigate the role of E23K in the development of prediabetes, 279 subjects with prediabetes and 240 normal controls (mean [± SD] age 18.1 ± 3.2 and 17.8 ± 4.3 years, respectively) were recruited to the study. Height, weight, and hip and waist circumferences were measured by trained physicians. Genotyping of KCNJ11 polymorphisms and clinical laboratory tests to determine cholesterol, triglyceride (TG), blood glucose, and insulin levels were performed.

RESULTS

The carrier rate of K23 allele-containing genotypes was higher for prediabetic than control subjects (P = 0.005). Logistic regression analyses revealed that higher body mass index percentiles (P = 0.013), lower insulin levels at 30 min during an oral glucose tolerance test (P = 0.001), a higher ratio of total cholesterol: high-density lipoprotein cholesterol (P = 0.001), and a K allele-containing genotype (P = 0.019) are independent risk factors for prediabetes in Chinese Han youth. Furthermore, K23 allele-containing genotypes were associated with impaired indices of insulin secretion and β-cell function in female youth with prediabetes. These effects were not seen in male youth with prediabetes.

CONCLUSIONS

The results confirm that the common E23K polymorphism of KCNJ11 carries a higher susceptibility to the development of prediabetes in the Chinese Han population. The results suggest that E23K may have a greater effect on the development of T2D in female Chinese youth.

Increased mitochondrial calcium uniporter in adipocytes underlies mitochondrial alterations associated with insulin resistance

Intracellular calcium influences an array of pathways and affects cellular processes. With the rapidly progressing research investigating the molecular identity and the physiological roles of the mitochondrial calcium uniporter (MCU) complex, we now have the tools to understand the functions of mitochondrial Ca²⁺ in the regulation of pathophysiological processes. Herein, we describe the role of key MCU complex components in insulin resistance in mouse and human adipose tissue. Adipose tissue gene expression was analyzed from several models of obese and diabetic rodents and in 72 patients with obesity as well as in vitro insulin-resistant adipocytes. Genetic manipulation of MCU activity in 3T3-L1 adipocytes allowed the investigation of the role of mitochondrial calcium uptake. In insulin-resistant adipocytes, mitochondrial calcium uptake increased and several MCU components were upregulated. Similar results were observed in mouse and human visceral adipose tissue (VAT) during the progression of obesity and diabetes. Intriguingly, subcutaneous adipose tissue (SAT) was spared from overt MCU fluctuations. Furthermore, MCU expression returned to physiological levels in VAT of patients after weight loss by bariatric surgery. Genetic manipulation of mitochondrial calcium uptake in 3T3-L1 adipocytes demonstrated that changes in mitochondrial calcium concentration ([Ca²⁺]_mt) can affect mitochondrial metabolism, including oxidative enzyme activity, mitochondrial respiration, membrane potential, and reactive oxygen species formation. Finally, our data suggest a strong relationship between [Ca²⁺]_mt and the release of IL-6 and TNFα in adipocytes. Altered mitochondrial calcium flux in fat cells may play a role in obesity and diabetes and may be associated with the differential metabolic profiles of VAT and SAT.

Duodenal Sodium/Glucose Cotransporter 1 Expression Under Fasting Conditions Is Associated With Postload Hyperglycemia

CONTEXT

Type 2 diabetes (T2DM) is associated with a higher intestinal expression of the glucose transporters sodium/glucose cotransporter 1 (SGLT-1) and glucose transporter 2 (GLUT-2). It is currently unsettled whether prediabetes conditions characterized by postprandial hyperglycemia, such as impaired glucose tolerance (IGT) and normal glucose tolerance (NGT) with 1-hour postload glucose ≥155 mg/dL (8.6 mmol/L) (NGT-1h-high) are associated with increased expression of these glucose carriers in the intestine.

OBJECTIVE

We evaluated whether duodenal abundance of SGLT-1 and GLUT-2 is augmented in subjects with IGT and NGT-1h-high, in comparison with subjects with NGT and 1-hour postload glucose ˂155 mg/dL (NGT-1h-low).

DESIGN

Cross-sectional.

PATIENTS

A total of 54 individuals underwent an upper gastrointestinal endoscopy.

MAIN OUTCOME MEASURES

Duodenal SGLT-1 and GLUT-2 protein and messenger RNA levels were assessed by Western blot and reverse transcription polymerase chain reaction, respectively.

RESULTS

Of the 54 subjects examined, 18 had NGT-1h-low, 12 had NGT-1h-high, 12 had IGT, and 12 had T2DM. Duodenal SGLT-1 protein and messenger RNA levels were significantly higher in individuals with NGT-1h-high, IGT, or T2DM in comparison with NGT-1h-low subjects. GLUT-2 abundance was higher in individuals with T2DM in comparison with NGT-1h-low subjects; no substantial increase in GLUT-2 expression was observed in NGT-1h-high or IGT individuals. Univariate correlations showed that duodenal SGLT-1 abundance was positively correlated with 1-hour postload plasma glucose levels (r = 0.44; P = 0.003) but not with fasting or 2-hour postload glucose levels.

CONCLUSIONS

Duodenal SGLT-1 expression is increased in individuals with 1-hour postload hyperglycemia or IGT, as well as in subjects with T2DM, and it positively correlates with early postload glucose excursion.

Blood pathway analyses reveal differences between prediabetic subjects with or without dyslipidaemia. The Cardiovascular Risk in Young Finns Study

BACKGROUND

Prediabetes often occurs together with dyslipidaemia, which is paradoxically treated with statins predisposing to type 2 diabetes mellitus. We examined peripheral blood pathway profiles in prediabetic subjects with (PR_D ) and without dyslipidaemia (PR₀ ) and compared these to nonprediabetic controls without dyslipidaemia (C₀ ).

METHODS

The participants were from the Cardiovascular Risk in Young Finns Study, including 1240 subjects aged 34 to 49 years. Genome-wide expression data of peripheral blood and gene set enrichment analysis were used to investigate the differentially expressed genes and enriched pathways between different subtypes of prediabetes.

RESULTS

Pathways for cholesterol synthesis, interleukin-12-mediated signalling events, and downstream signalling in naïve CD8+ T-cells were upregulated in the PR₀ group in comparison with controls (C₀ ). The upregulation of these pathways was independent of waist circumference, blood pressure, smoking status, and insulin. Adjustment for CRP left the CD8+ T-cell signalling and interleukin-12-mediated signalling event pathway upregulated. The cholesterol synthesis pathway was also upregulated when all prediabetic subjects (PR₀ and PR_D ) were compared with the nonprediabetic control group. No pathways were upregulated or downregulated when the PR_D group was compared with the C₀ group. Five genes in the PR₀ group and 1 in the PR_D group were significantly differentially expressed in comparison with the C₀ group.

CONCLUSIONS

Blood cell gene expression profiles differ significantly between prediabetic subjects with and without dyslipidaemia. Whether this classification may be used in detection of prediabetic individuals at a high risk of cardiovascular complications remains to be examined.

Genetic risk of prediabetes and diabetes development in chronic myeloid leukemia patients treated with nilotinib

Impaired fasting glucose and type 2 diabetes represent adverse events in patients with chronic myeloid leukemia (CML) treated with the second generation tyrosine kinase inhibitor nilotinib. An unweighted genetic risk score (uGRS) for the prediction of insulin resistance, consisting of 10 multiple single-nucleotide polymorphisms, has been proposed. We evaluated uGRS predictivity in 61 CML patients treated with nilotinib. Patients were genotyped for IRS1, GRB14, ARL15, PPARG, PEPD, ANKRD55/MAP3K1, PDGFC, LYPLAL1, RSPO3, and FAM13A1 genes. The uGRS was based on the sum of the risk alleles within the set of selected single-nucleotide polymorphisms. Molecular response (MR)^3.0 and MR^4.0 were achieved in 90% and 79% of patients, respectively. Before treatment, none of the patients had abnormal blood glucose. During treatment and subsequent follow-up at 80.2 months (range: 1-298), seven patients (11.5%) had developed diabetes that required oral treatment, a median of 14 months (range: 3-98) after starting nilotinib treatment. Twelve patients (19.7%) had developed prediabetes. Prediabetes/diabetes-free survival was significantly higher in patients with a uGRS <10 than in those with higher scores (100% vs. 22.8 ± 12.4%, p <0.001). Each increment of one unit in the uGRS caused a 42% increase in the prediabetes/diabetes risk (hazard ratio = 1.42, confidence interval: 1.04-1.94, p = 0.026). The presence of more than 10 allelic variants associated with insulin secretion, processing, sensitivity, and clearance is predictive of prediabetes/diabetes development in CML patients treated with nilotinib. In clinical practice, uGRS could help tailor the best tyrosine kinase inhibitor therapy.

Lifestyle determinants of health: Isn't it all about genetics and environment?

PURPOSE

Drawn from one of the keynote addresses at the State of the Science Conference held by the Council for the Advancement of Nursing Science (CANS), the purpose of this paper is to review the evidence from clinical trials about the importance of lifestyle behaviors in human health.

METHODS

Evidence from trials on the impact of lifestyle interventions on outcomes in diabetes and prediabetes are presented.

RESULTS

These findings suggest that lifestyle behaviors are important to diabetes prevention and outcomes in youth and adults.

IMPLICATIONS

More research is needed on the factors that predict these outcomes, especially genetics and environment.

Vitamin D3 supplementation of a high fat high sugar diet ameliorates prediabetic phenotype in female LDLR-/- and LDLR+/+ mice

INTRODUCTION

Fatty liver disease is prevalent in populations with high caloric intake. Nutritherapeutic approaches are being considered, such as supplementary Vitamin D3 , to improve aspects of metabolic syndrome, namely fatty liver disease, hyperlipidemia, and insulin resistance associated with obesity.

METHODS

We analyzed female LDLR-/- and LDLR+/+ mice on a 10-week diabetogenic diet for markers of fatty liver disease, metabolic strain, and inflammation.

RESULTS

The groups on a high fat high sugar diet with supplementary Vitamin D3 , in comparison with the groups on a high fat high sugar diet alone, showed improved transaminase levels, significantly less hypertriglyceridemia and hyperinsulinemia, and histologically, there was less pericentral hepatic steatosis. Levels of non-esterified fatty acids and lipid peroxidation products were significantly lower in the group supplemented with additional Vitamin D3 , as were systemic markers of inflammation (serum endotoxin and IL-6). M2 macrophage phenotype predominated in the group supplemented with additional Vitamin D3 . Beneficial changes were observed as early as five weeks' supplementation with Vitamin D3 and extended to restoration of high fat high sugar diet induced decrease of bone mineral density.

CONCLUSION

In summary, Vitamin D3 was a significantly beneficial dietary additive to blunt a prediabetic phenotype in diet-induced obesity of female LDLR-/- and LDLR+/+ mice.

Serum magnesium and the risk of prediabetes: a population-based cohort study

AIMS/HYPOTHESIS

Previous studies have found an association between serum magnesium and incident diabetes; however, this association may be due to reverse causation, whereby diabetes may induce urinary magnesium loss. In contrast, in prediabetes (defined as impaired fasting glucose), serum glucose levels are below the threshold for urinary magnesium wasting and, hence, unlikely to influence serum magnesium levels. Thus, to study the directionality of the association between serum magnesium levels and diabetes, we investigated its association with prediabetes. We also investigated whether magnesium-regulating genes influence diabetes risk through serum magnesium levels. Additionally, we quantified the effect of insulin resistance in the association between serum magnesium levels and diabetes risk.

METHODS

Within the population-based Rotterdam Study, we used Cox models, adjusted for age, sex, lifestyle factors, comorbidities, kidney function, serum levels of electrolytes and diuretic use, to study the association between serum magnesium and prediabetes/diabetes. In addition, we performed two mediation analyses: (1) to study if common genetic variation in eight magnesium-regulating genes influence diabetes risk through serum magnesium levels; and (2) to quantify the proportion of the effect of serum magnesium levels on diabetes that is mediated through insulin resistance (quantified by HOMA-IR).

RESULTS

A total of 8555 participants (mean age, 64.7 years; median follow-up, 5.7 years) with normal glucose levels (mean ± SD: 5.46 ± 0.58 mmol/l) at baseline were included. A 0.1 mmol/l decrease in serum magnesium level was associated with an increase in diabetes risk (HR 1.18 [95% CI 1.04, 1.33]), confirming findings from previous studies. Of interest, a similar association was found between serum magnesium levels and prediabetes risk (HR 1.12 [95% CI 1.01, 1.25]). Genetic variation in CLDN19, CNNM2, FXYD2, SLC41A2, and TRPM6 significantly influenced diabetes risk (p < 0.05), and for CNNM2, FXYD2, SLC41A2 and TRPM6 this risk was completely mediated by serum magnesium levels. We found that 29.1% of the effect of serum magnesium levels on diabetes was mediated through insulin resistance, whereas for prediabetes 13.4% was mediated through insulin resistance.

CONCLUSIONS/INTERPRETATION

Low serum magnesium levels are associated with an increased risk of prediabetes and this increased risk is similar to that of diabetes. Furthermore, common variants in magnesium-regulating genes modify diabetes risk through serum magnesium levels. Both findings support a potential causal role of magnesium in the development of diabetes, where the hypothesised pathway is partly mediated through insulin resistance.

Hsa_circ_0054633 in peripheral blood can be used as a diagnostic biomarker of pre-diabetes and type 2 diabetes mellitus

AIMS

The purpose of the current study was to investigate the characteristic expression of circular RNAs (circRNAs) in the peripheral blood of type 2 diabetes mellitus (T2DM) patients and their potential as diagnostic biomarkers for pre-diabetes and T2DM.

METHODS

CircRNAs in the peripheral blood from six healthy individuals and six T2DM patients were collected for microarray analysis, and an independent cohort study consisting of 20 normal cases, 20 pre-diabetes patients and 20 T2DM patients was conducted to verify the five chosen circRNAs. We then tested hsa_circ_0054633 in a third cohort (control group, n = 60; pre-diabetes group, n = 63; and T2DM group, n = 64) by quantitative real-time polymerase chain reaction (Q-PCR).

RESULTS

In total, 489 circRNAs were discovered to be differentially expressed between the two groups, and of these, 78 were upregulated and 411 were downregulated in the T2DM group. Five circRNAs were then selected as candidate biomarkers and further verified in a second cohort. Hsa_circ_0054633 was found to have the largest area under the curve (AUC). The diagnostic capacity of hsa_circ_0054633 was tested in a third cohort. After introducing the risk factors of T2DM, the hsa_circ_0054633 AUCs for the diagnosis of pre-diabetes and T2DM slightly increased from 0.751 (95% confidence interval [0.666-0.835], P < 0.001) to 0.841 ([0.773-0.910], P < 0.001) and from 0.793 ([0.716-0.871], P < 0.001) to 0.834 ([0.762-0.905], P < 0.001), respectively.

CONCLUSIONS

Hsa_circ_0054633 presented a certain diagnostic capability for pre-diabetes and T2DM.

Association of prediabetes-associated single nucleotide polymorphisms with microalbuminuria

Increased glycemic exposure, even below the diagnostic criteria for diabetes mellitus, is crucial in the pathogenesis of diabetic microvascular complications represented by microalbuminuria. Nonetheless, there is limited evidence regarding which single nucleotide polymorphisms (SNPs) are associated with prediabetes and whether genetic predisposition to prediabetes is related to microalbuminuria, especially in the general population. Our objective was to answer these questions. We conducted a genomewide association study (GWAS) separately on two population-based cohorts, Ansung and Ansan, in the Korean Genome and Epidemiology Study (KoGES). The initial GWAS was carried out on the Ansung cohort, followed by a replication study on the Ansan cohort. A total of 5682 native Korean participants without a significant medical illness were classified into either control group (n = 3153) or prediabetic group (n = 2529). In the GWAS, we identified two susceptibility loci associated with prediabetes, one at 17p15.3-p15.1 in the GCK gene and another at 7p15.1 in YKT6. When variations in GCK and YKT6 were used as a model of prediabetes, this genetically determined prediabetes increased microalbuminuria. Multiple logistic regression analyses revealed that fasting glucose concentration in plasma and SNP rs2908289 in GCK were associated with microalbuminuria, and adjustment for age, gender, smoking history, systolic blood pressure, waist circumference, and serum triglyceride levels did not attenuate this association. Our results suggest that prediabetes and the associated SNPs may predispose to microalbuminuria before the diagnosis of diabetes mellitus. Further studies are needed to explore the details of the physiological and molecular mechanisms underlying this genetic association.

Catalase deletion promotes prediabetic phenotype in mice

Hydrogen peroxide is produced endogenously and can be toxic to living organisms by inducing oxidative stress and cell damage. However, it has also been identified as a signal transduction molecule. By metabolizing hydrogen peroxide, catalase protects cells and tissues against oxidative damage and may also influence signal transduction mechanisms. Studies suggest that acatalasemic individuals (i.e., those with very low catalase activity) have a higher risk for the development of diabetes. We now report catalase knockout (Cat^-/-) mice, when fed a normal (6.5% lipid) chow, exhibit an obese phenotype that manifests as an increase in body weight that becomes more pronounced with age. The mice demonstrate altered hepatic and muscle lipid deposition, as well as increases in serum and hepatic triglycerides (TGs), and increased hepatic transcription and protein expression of PPARγ. Liver morphology revealed steatosis with inflammation. Cat^-/- mice also exhibited pancreatic morphological changes that correlated with impaired glucose tolerance and increased fasting serum insulin levels, conditions consistent with pre-diabetic status. RNA-seq analyses revealed a differential expression of pathways and genes in Cat^-/- mice, many of which are related to metabolic syndrome, diabetes, and obesity, such as Pparg and Cidec. In conclusion, the results of the present study show mice devoid of catalase develop an obese, pre-diabetic phenotype and provide compelling evidence for catalase (or its products) being integral in metabolic regulation.

Prevalence of Prediabetes Risk in Offspring Born to Mothers with Hyperandrogenism

Background

Excessive androgen exposure during pregnancy has been suggested to induce diabetic phenotypes in offspring in animal models. The aim of this study was to investigate whether pregestational maternal hyperandrogenism in human influenced the glucose metabolism in offspring via epigenetic memory from mother's oocyte to child's somatic cells.

Methods

Of 1782 reproductive-aged women detected pregestational serum androgen, 1406 were pregnant between 2005 and 2010. Of 1198 women who delivered, 1116 eligible mothers (147 with hyperandrogenism and 969 normal) were recruited. 1216 children (156 children born to mothers with hyperandrogenism and 1060 born to normal mother) were followed up their glycometabolism in mean age of 5 years. Imprinting genes of oocyte from mothers and lymphocytes from children were examined. A pregestational hyperandrogenism rat model was also established.

Findings

Children born to women with hyperandrogenism showed increased serum fasting glucose and insulin levels, and were more prone to prediabetes (adjusted RR: 3.98 (95%CI 1.16–13.58)). Oocytes from women with hyperandrogenism showed increased insulin-like growth factor 2 (IGF2) expression. Lymphocytes from their children also showed increased IGF2 expression and decreased IGF2 methylation. Treatment of human oocytes with dihydrotestosterone upregulated IGF2 and downregulated DNMT3a levels. In rat, pregestational hyperandrogenism induced diabetic phenotypes and impaired insulin secretion in offspring. In consistent with the findings in human, hyperandrogenism also increased Igf2 expression and decreased DNMT3a in rat oocytes. Importantly, the same altered methylation signatures of Igf2 were identified in the offspring pancreatic islets.

Interpretation

Pregestational hyperandrogenism may predispose offspring to glucose metabolism disorder via epigenetic oocyte inheritance.

Clinical trial registry no.: ChiCTR-OCC-14004537; www.chictr.org.

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Maternal hyperandrogenism may increase the risks of glucose metabolism disorder and prediabetes in their children.

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High androgen levels in women may directly increased IGF2 expression and decreased IGF2 methylation in oocytes

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Intergenerational inheritance of epigenetic alteration could be regarded important in determining development of diabetes.

Hyperandrogenemia can be observed in most patients with polycystic ovarian syndrome that is a common endocrine disorder in women of reproductive age, especially in subfertile women. We found that maternal hyperandrogenism may increase the risks of glucose metabolism disorder and prediabetes in their children. Also, Data from human and rat suggest that this glucose metabolism disorder may be mediated by DNA methylation modifications, and this kind of epigenetic modification may be transmitted from oocytes of mothers to somatic cells of offspring. Hence, intergenerational inheritance of epigenetic alteration should be regarded important in determining development of diabetes in the future.

ADIPOQ POLYMORPHISMS AMONG THAIS WITH PRE-DIABETES

Studies have shown that polymorphisms of adiponectin gene (ADIPOQ) are associated with risk of developing type 2 diabetes mellitus (T2DM). However, no studies have investigated the association between genetic variants of ADIPOQ and pre-diabetes, a group at higher risk for developing T2DM. A total of 75 pre-diabetes and 130 normal subjects were recruited from volunteers in Bangkok, Thailand. Individuals with pre-diabetes were selected based on American Diabetes Association diagnostic criteria. Six ADIPOQ polymorphisms were genotyped using polymerase chain reaction-restriction fragment length polymorphism technique. ADIPOQ polymorphism rs266729 C>G is significantly associated with pre-diabetes (p = 0.006). CG/GG genotypes were found among 60% and 40% of pre-diabetes and normal subjects, respectively. SNP rs266729 C>G was associated with increased pre-diabetes risk (OR = 2.64; 95% CI: 1.18-5.89, p = 0.018). No significant differences were found between pre-diabetes and normal subjects for other ADIPOQ polymorphisms. However, haplotype analysis revealed that haplotype GGTAAT is significantly associated with pre-diabetes when compared with GCGAAC reference haplotype (OR = 22.31; 95% CI: 1.37-361.93, p = 0.03). Our data indicate that ADIPOQ rs266729 C>G polymorphism may contribute to the genetic risk of pre-diabetes and provide preliminary data useful in genetic screening for pre-diabetes among Thais.

The role of the p53 tumor suppressor in metabolism and diabetes

In the context of tumor suppression, p53 is an undisputedly critical protein. Functioning primarily as a transcription factor, p53 helps fend off the initiation and progression of tumors by inducing cell cycle arrest, senescence or programmed cell death (apoptosis) in cells at the earliest stages of precancerous development. Compelling evidence, however, suggests that p53 is involved in other aspects of human physiology, including metabolism. Indeed, recent studies suggest that p53 plays a significant role in the development of metabolic diseases, including diabetes, and further that p53's role in metabolism may also be consequential to tumor suppression. Here, we present a review of the literature on the role of p53 in metabolism, diabetes, pancreatic function, glucose homeostasis and insulin resistance. Additionally, we discuss the emerging role of genetic variation in the p53 pathway (single-nucleotide polymorphisms) on the impact of p53 in metabolic disease and diabetes. A better understanding of the relationship between p53, metabolism and diabetes may one day better inform the existing and prospective therapeutic strategies to combat this rapidly growing epidemic.

Diagnosis of prediabetes in cats: glucose concentration cut points for impaired fasting glucose and impaired glucose tolerance

Diabetes is typically diagnosed in cats once clinical signs are evident. Diagnostic criteria for prediabetes in cats have not been defined. The objective of the study was to establish methodology and cut points for fasting and 2-h blood glucose concentrations in healthy client-owned senior cats (≥8 yr) using ear/paw samples and a portable glucose meter calibrated for feline blood. Of the 78 cats, 27 were ideal (body condition score [BCS] 4 or 5 of 9), 31 overweight (BCS 6 or 7), and 20 obese (BCS 8 or 9); 19 were Burmese and 59 non-Burmese. After an 18-24-h fast and an ear/paw blood glucose measurement using a portable glucose meter, glucose (0.5 g/kg bodyweight) was administered intravenous and blood glucose measured at 2 min and 2 h. Cut points for fasting and 2-h glucose concentrations were defined as the upper limits of 95% reference intervals using cats with BCS 4 or 5. The upper cut point for fasting glucose was 6.5 mmol/L. Of the overweight and obese cats, 1 (BCS 7) was above this cut point indicating evidence of impaired fasting glucose. The cut point for 2-h glucose was 9.8 mmol/L. A total of 7 cats (4 with BCS 8 or 9 including 1 Burmese; 3 with BCS 6 or 7, non-Burmese) were above this cut point and thus had evidence of impaired glucose tolerance. In conclusion, the methodology and cutpoints for diagnosis of prediabetes are defined for use in healthy cats 8 yr and older with a range of BCSs.

Serum microRNA-196 and microRNA-200 in pancreatic ductal adenocarcinoma of patients with diabetes mellitus

BACKGROUND/OBJECTIVES

Our aim was to compare expressions of 6 microRNAs (miRNAs) in patients with pancreatic ductal adenocarcinoma (PAC) and non-cancer patients, moreover according to the presence or absence of diabetes mellitus.

METHODS

Expressions of miRNA-192, -196, -200, -21, -30 and -423 were measured in 77 patients with PAC and 64 non-cancer patients (34 patients with type 2 DM and 30 control persons). 60 patients with PAC (78%) had DM or prediabetes and it was of new-onset (less than 2 years before the cancer diagnosis) in 44 out of them.

RESULTS

The expressions of all microRNAs were 1.4-3.7 times higher (significantly) in the PAC group compared to non-cancer patients. No difference was found between PAC diabetic and PAC non-diabetic patients. MicroRNA-200 was significantly higher in PAC patients with significant body weight loss against those without weight loss. Adding miRNA-196 and -200 to the current marker CA 19-9 improved the discriminative ability of the test (compared to CA 19-9 alone).

CONCLUSION

MicroRNA-196 and -200 could be used as additional markers in PAC diagnosis.

Effects of vitamin D binding protein phenotypes and vitamin D supplementation on serum total 25(OH)D and directly measured free 25(OH)D

OBJECTIVE

To determine the relationship between serum total 25-hydroxyvitamin D (25(OH)D), directly measured free 25(OH)D and calculated free 25(OH)D with regard to vitamin D-binding protein (DBP) phenotypes, sex, BMI, age and season, and their interrelationship to vitamin D supplementation.

DESIGN, PATIENTS AND INTERVENTIONS

A randomized controlled trial with 20 000 IU of vitamin D3 per week or placebo for 12 months was designed. A total of 472 subjects, 236 in each of the intervention groups, were included in the analyses.

MAIN OUTCOME MEASURES

Baseline serum concentrations and increases in serum total 25(OH)D, directly measured free 25(OH)D, calculated free 25(OH)D and DBP.

RESULTS

Serum total 25(OH)D and DBP concentrations were significantly lower in subjects with the phenotype Gc2/Gc2 compared to phenotypes with the Gc1S allele, and lower in males compared to females. When using directly measured free 25(OH)D, the differences related to DBP phenotypes and sexes were clearly diminished. All calculated free 25(OH)D concentrations were overestimated compared to the directly measured free 25(OH)D. Serum parathyroid hormone showed an inverse correlation with all vitamin D parameters analyzed. The increases after 12 months of vitamin D supplementation were not significantly different for any of the vitamin D parameters regardless of DBP phenotype, sex or age. Supplementation with vitamin D did not affect serum DBP.

CONCLUSION

Direct measurements of free 25(OH)D reduce the differences seen in total 25(OH)D between DBP phenotype groups and sexes, probably caused by differences in DBP concentrations. With conditions affecting serum DBP concentrations, direct measurements of free 25(OH)D should be considered.

Reduced β-cell function in early preclinical type 1 diabetes

OBJECTIVE

We aimed to characterize insulin responses to i.v. glucose during the preclinical period of type 1 diabetes starting from the emergence of islet autoimmunity.

DESIGN AND METHODS

A large population-based cohort of children with HLA-conferred susceptibility to type 1 diabetes was observed from birth. During regular follow-up visits islet autoantibodies were analysed. We compared markers of glucose metabolism in sequential intravenous glucose tolerance tests between 210 children who were positive for multiple (≥2) islet autoantibodies and progressed to type 1 diabetes (progressors) and 192 children testing positive for classical islet-cell antibodies only and remained healthy (non-progressors).

RESULTS

In the progressors, the first phase insulin response (FPIR) was decreased as early as 4-6 years before the diagnosis when compared to the non-progressors (P=0.001). The difference in FPIR between the progressors and non-progressors was significant (P<0.001) in all age groups, increasing with age (at 2 years: difference 50% (95% CI 28-75%) and at 10 years: difference 172% (95% CI 128-224%)). The area under the 10-min insulin curve showed a similar difference between the groups (P<0.001; at 2 years: difference 36% (95% CI 17-58%) and at 10 years: difference 186% (95% CI 143-237%)). Insulin sensitivity did not differ between the groups.

CONCLUSIONS

FPIR is decreased several years before the diagnosis of type 1 diabetes, implying an intrinsic defect in β-cell mass and/or function.

[Association between VDR gene polymorphisms and HOMA index for prediabetes in Ningxia]

OBJECTIVE

To explore the association between the vitamin D receptor (VDR) gene polymorphisms and HOMA index in prediabetes.

METHODS

On the basis of a cross-sectional study which was conducted in Ningxia during 2008-2012, 339 controls and 468 subjects with prediabetes were selected according to ADA diabetes diagnosis standards. Anthropometric data and blood samples were collected in the field investigation. Blood biochemistry analyses and insulin determination were carried out in the laboratory. The whole blood DNA was extracted for genotyping.

RESULTS

The BMI, WC, FPG and HOMA-IR of individuals with prediabetes were higher than those of the controls, while the HOMA-B and HOMA-S in cases were lower than those of the controls (P < 0.05). In BsmI, individuals with prediabetes carrying genotype BB/Bb showed lower HOMA-B than bb carrier, and they showed significantly higher HOMA-S than bb carriers (P < 0.05). After adjusting age, sex, BMI, TC, TG and SBP, low level HOMA-B index was the risk factor of prediabetes in individuals who carried genotype BB/Bb for BsmI and genotype FF/Ff/ff for FokI (OR > 1 , P < 0.05 ), and the genotype ff got the highest risk level (OR = 10.59). In FokI, the Ff carriers with low level HOMA-S and HOM-IR were also the risk factors of prediabetes (OR > 1, P < 0.05).

CONCLUSION

The VDR gene polymorphisms appeared to be associated with HOMA index in prediabetes. The BsmI polymorphism seemed to influence HOMA-B, while the FokI polymorphism influence HOMA-B and HOMA-IR at different levels.

Ovariectomy is associated with metabolic impairments and enhanced mammary tumor growth in MKR mice

Obesity and type 2 diabetes (T2D) are associated with an increased risk of breast cancer incidence and mortality. Common features of obesity and T2D are insulin resistance and hyperinsulinemia. A mammary tumor promoting effect of insulin resistance and hyperinsulinemia was demonstrated in the transgenic female MKR mouse model of pre-diabetes inoculated with mammary cancer cells. Interestingly, in MKR mice, as well as in other diabetic mouse models, males exhibit severe hyperglycemia, while females display insulin resistance and hyperinsulinemia with only a mild increase in blood glucose levels. This gender-specific protection from hyperglycemia may be attributed to estradiol, a key player in the regulation of the metabolic state, including obesity, glucose homeostasis, insulin resistance, and lipid profile. The aim of this study was to investigate the effects of ovariectomy (including the removal of endogenous estradiol) on the metabolic state of MKR female mice and subsequently on the growth of Mvt-1 mammary cancer cells, inoculated into the mammary fat pad of ovariectomized mice, compared with sham-operated mice. The results showed an increase in body weight, accompanied by increased fat mass, elevated blood glucose levels, and hypercholesterolemia, in ovariectomized MKR mice. In addition, mammary tumor growth was significantly higher in these mice. The results suggest that ovarian hormone deficiency may promote impaired metabolic homeostasis in the hyperinsulinemic MKR female mice, which in turn is associated with an increased growth of mammary tumors.

HHEX_23 AA Genotype Exacerbates Effect of Diabetes on Dementia and Alzheimer Disease: A Population-Based Longitudinal Study

BACKGROUND

Research has suggested that variations within the IDE/HHEX gene region may underlie the association of type 2 diabetes with Alzheimer disease (AD). We sought to explore whether IDE genes play a role in the association of diabetes with dementia, AD, and structural brain changes using data from two community-based cohorts of older adults and a subsample with structural MRI.

METHODS AND FINDINGS

The first cohort, which included dementia-free adults aged ≥75 y (n = 970) at baseline, was followed for 9 y to detect incident dementia (n = 358) and AD (n = 271) cases. The second cohort (for replication), which included 2,060 dementia-free participants aged ≥60 y at baseline, was followed for 6 y to identify incident dementia (n = 166) and AD (n = 121) cases. A subsample (n = 338) of dementia-free participants from the second cohort underwent MRI. HHEX_23 and IDE_9 were genotyped, and diabetes (here including type 2 diabetes and prediabetes) was assessed. In the first cohort, diabetes led to an adjusted hazard ratio (HR) of 1.73 (95% CI 1.19-2.32) and 1.66 (95% CI 1.06-2.40) for dementia and AD, respectively, among all participants. Compared to people carrying the GG genotype without diabetes, AA genotype carriers with diabetes had an adjusted HR of 5.54 (95% CI 2.40-7.18) and 4.81 (95% CI 1.88-8.50) for dementia and AD, respectively. There was a significant interaction between HHEX_23-AA and diabetes on dementia (HR 4.79, 95% CI 1.63-8.90, p = 0.013) and AD (HR 3.55, 95% CI 1.45-9.91, p = 0.025) compared to the GG genotype without diabetes. In the second cohort, the HRs were 1.68 (95% CI 1.04-2.99) and 1.64 (1.02-2.33) for the diabetes-AD and dementia-AD associations, respectively, and 4.06 (95% CI 1.06-7.58, p = 0.039) and 3.29 (95% CI 1.02-8.33, p = 0.044) for the interactions, respectively. MRI data showed that HHEX_23-AA carriers with diabetes had significant structural brain changes compared to HHEX_23-GG carriers without diabetes. No joint effects of IDE_9 and diabetes on dementia were shown. As a limitation, the sample sizes were small for certain subgroups.

CONCLUSIONS

A variant in the HHEX_23 gene interacts with diabetes to be associated with a substantially increased risk of dementia and AD, and with structural brain changes among dementia-free elderly people.

Prevalence of abnormal glycometabolism in treatment-naive patients with hepatitis C virus infection in a Chinese Han population

BACKGROUND AND AIM

The hepatitis C virus (HCV) may promote pancreatic β-cell apoptosis-like cell death through a caspase 3-dependent pathway, initiating the onset of type 2 diabetes mellitus (T2DM); however, the risk factors for development of T2DM and other abnormal glycometabolic factors in HCV patients of the Chinese Han ethnicity have been poorly explored.

METHODS

A total of 947 patients Chinese Han patients with confirmed HCV infection were enrolled in a multicenter study in order to examine the genetic and physiological parameters associated with the onset of abnormal glycometabolic conditions, including T2DM and prediabetes.

RESULTS

HCV genotype 1b and host interleukin-28B CC genotype were most commonly observed. A total of 145 (15.3%) patients were diagnosed with T2DM and prediabetes. Elevated age, waist circumference, smoking duration, and systolic and diastolic blood pressure were shown to increase risks for abnormal glycometabolism. Liver dysfunction was shown to have positive correlations with abnormal glycometabolism in HCV patients. Genome-wide association studies indicated that certain genetic encoding inosine triphosphatase polymorphs (rs6051702) were associated with elevated risks for abnormal glycometabolism. Coupled with previous research data, it is likely that abnormal glycometabolism may be a useful predictor of risk for poor response to antiviral therapies and treatment-induced complications, such as anemia, in treatment naïve patients.

CONCLUSIONS

Abnormal glycometabolism and other such complications of HCV and HCV treatment may share critical metabolic and genetic pathways, providing potentially novel targets for future antiviral therapies for treatment resistant HCV genotypes.

Retinol binding protein-4 predicts incident diabetes in Asian Indian men with prediabetes

The association of retinol binding protein-4 (RBP4) with incident type 2 diabetes (T2DM) in Asian Indian middle-aged men with impaired glucose tolerance (IGT) was studied. This was an ancillary analysis of a subsample from a cohort of participants with IGT in a 2 year prospective diabetes prevention program in India. For this analysis, 71 incident T2DM and 76 non-diabetic cases (non-progressors) based on the final glycemic outcome were selected. Baseline serum RBP4 was measured using competitive enzyme immunoassay. Correlations of RBP4 with relevant anthropometric and biochemical variables and also its association with diabetes were assessed using appropriate statistical analyses. Participants who developed T2DM had higher levels of serum RBP4 (21.3 [IQR: 17.7-24.9] µg/mL) compared with non-progressors (17.3 [IQR: 13.1-21.0] µg/mL; P = 0.001). Levels of RBP4 were lower than in Caucasians. Stepwise linear regression analysis showed that body mass index (BMI), systolic blood pressure, triglycerides, and HbA1c had independent associations with RBP4 levels. Multiple logistic regression analyses showed that RBP4 was independently associated with incident diabetes (odds ratio [OR] [95%confidence interval (CI)]: 1.69 [1.18-2.41]; P = 0.004). Adjustment for study group, age, BMI, waist circumference, 2 H plasma glucose, triglycerides, gamma glutamyl transferase, and insulin resistance weakened the significance of its association (OR [95%CI]: 1.65 [1.03-2.66]; P = 0.038).The results of this preliminary analyses showed that baseline serum RBP4 levels were independently associated with incident diabetes in Asian Indian men with IGT. It may be used as an additional predictor of future diabetes.

Habitual coffee intake, genetic polymorphisms, and type 2 diabetes

BACKGROUND

The association between coffee intake and type 2 diabetes may be modulated by common genetic variation.

OBJECTIVE

The purpose of this study was to examine the association between habitual coffee intake and the risk of type 2 diabetes and to determine whether this association varied by genetic polymorphisms related to type 2 diabetes in Korean adults.

DESIGN AND METHODS

A population-based cohort study over a follow-up of 4 years was conducted. A total of 4077 Korean men and women aged 40-69 years with a normal glucose level at baseline were included. Coffee intake was assessed using a validated food frequency questionnaire, and incident type 2 diabetes or prediabetes was defined by oral glucose tolerance test or fasting blood glucose test. The genomic DNA samples were genotyped with the Affymetrix Genome-Wide Human SNP Array 5.0, and nine single-nucleotide polymorphisms related to type 2 diabetes in East Asian populations were extracted.

RESULTS

A total of 120 cases of type 2 diabetes and 1128 cases of prediabetes were identified. After adjustment for potential confounding factors, we observed an inverse association, but without any clear linear trend, between coffee intake and the combined risk of type 2 diabetes and prediabetes. We found that inverse associations between habitual coffee intake and the combined risk of type 2 diabetes and prediabetes were limited to those with the T-allele (GT/TT) of rs4402960 in IGF2BP2, those with the G-allele (GG/GC) of rs7754840 in CDKAL1, or those with CC of rs5215 in KCNJ11.

CONCLUSION

We found a lower risk of prediabetes and type 2 diabetes combined with coffee intake among individuals with the GT/TT of IGF2BP2 rs4402960, GG/GC of CDKAL1 rs7754840, or CC of KCNJ11 rs5215, which are known to be related to type 2 diabetes in East Asians.

A common variant in the MTNR1b gene is associated with increased risk of impaired fasting glucose (IFG) in youth with obesity

OBJECTIVE

To explore the role of MTNR1B rs10830963 and G6PC2 rs560887 variants in the pathogenesis of impaired fasting glucose (IFG) in obese adolescents.

METHODS

A total of 346 Caucasians, 218 African-Americans, and 217 Hispanics obese children and adolescents underwent an oral glucose tolerance test (OGTT) and 518 underwent the evaluation of insulin secretion by the oral minimal model (OMM). Also, 274 subjects underwent a second OGTT after 3.0 ± 2.1 years.

RESULTS

The MTNR1B rs10830963 variant was associated with higher fasting glucose levels and lower dynamic beta-cell response in Caucasians and Hispanics (P < 0.05) and conferred an increased risk of showing IFG to Caucasians (P = 0.05), African-Americans (P = 0.0066), and Hispanics (P = 0.024). Despite the association between the G6PC2 rs560887 and higher fasting glucose levels (P < 0.05), there was no association between this variant and IFG at baseline or at follow-up (all P > 0.10).

CONCLUSIONS

It has been shown for the first time in obese youth that the MTNR1B variant is associated with an increased risk of IFG.

Characterization of the Prediabetic State in a Novel Rat Model of Type 2 Diabetes, the ZFDM Rat

We recently established a novel animal model of obese type 2 diabetes (T2D), the Zucker fatty diabetes mellitus (ZFDM) rat strain harboring the fatty mutation (fa) in the leptin receptor gene. Here we performed a phenotypic characterization of the strain, focusing mainly on the prediabetic state. At 6-8 weeks of age, fa/fa male rats exhibited mild glucose intolerance and severe insulin resistance. Although basal insulin secretion was remarkably high in the isolated pancreatic islets, the responses to both glucose stimulation and the incretin GLP-1 were retained. At 10-12 weeks of age, fa/fa male rats exhibited marked glucose intolerance as well as severe insulin resistance similar to that at the earlier age. In the pancreatic islets, the insulin secretory response to glucose stimulation was maintained but the response to the incretin was diminished. In nondiabetic Zucker fatty (ZF) rats, the insulin secretory responses to both glucose stimulation and the incretin in the pancreatic islets were similar to those of ZFDM rats. As islet architecture was destroyed with age in ZFDM rats, a combination of severe insulin resistance, diminished insulin secretory response to incretin, and intrinsic fragility of the islets may cause the development of T2D in this strain.

Serum 25-hydroxyvitamin D and adipose tissue vitamin D receptor gene expression: relationship with obesity and type 2 diabetes

CONTEXT

The relationship between 25-hydroxyvitamin D [25(OH)D] and obesity and type 2 diabetes is not completely understood. Vitamin D receptor (VDR) expression in adipose tissue (AT) is related to obesity and might be regulated by 1,25-dihydroxyvitamin D3 [1,25(OH)2D3].

OBJECTIVE

To analyze serum 25(OH)D and VDR gene expression in AT according to body mass index (BMI) and glycemic status and the effect of 1,25(OH)2D3 on AT according to BMI.

DESIGN AND PATIENTS

Two cohorts were studied: 1) 118 subjects classified according to their BMI (lean, overweight, obese, or morbidly obese [MO]) and their glycemic status (normoglycemic [NG] and prediabetic and diabetic [P&D]); and 2) 30 obese subjects (BMI > 30 kg/m(2)) classified as NG and P&D. VDR gene expression was analyzed during preadipocyte differentiation and in vitro stimulation with 1,25(OH)2D3 of AT explants from donors with different BMI values.

SETTING

University Hospital.

MAIN OUTCOME MEASURES

Serum 25(OH)D, parathyroid hormone (PTH), and AT VDR gene expression.

RESULTS

25(OH)D levels were lower in P&D than NG subjects, significantly so in the lean and MO groups (P < .05). 25(OH)D levels correlated negatively with homeostasis model of assessment for insulin resistance (HOMA-IR) (r = -0.200; P = .032) and glucose (r = -0.295; P = .001), but not with BMI. VDR gene expression was higher in MO than in the other BMI groups (P < .05). 1,25(OH)2D3 increased VDR gene expression in AT from obese patients (P < .05) but not from lean subjects.

CONCLUSIONS

25(OH)D levels are diminished in P&D compared to NG subjects, independently of BMI, and are closely related to glucose metabolism variables, suggesting that vitamin D deficiency is associated more with carbohydrate metabolism than with obesity. Moreover, AT has a different response to 1,25(OH)2D3 depending on the degree of obesity.

Transcriptomic identification of ADH1B as a novel candidate gene for obesity and insulin resistance in human adipose tissue in Mexican Americans from the Veterans Administration Genetic Epidemiology Study (VAGES)

Type 2 diabetes (T2D) is a complex metabolic disease that is more prevalent in ethnic groups such as Mexican Americans, and is strongly associated with the risk factors obesity and insulin resistance. The goal of this study was to perform whole genome gene expression profiling in adipose tissue to detect common patterns of gene regulation associated with obesity and insulin resistance. We used phenotypic and genotypic data from 308 Mexican American participants from the Veterans Administration Genetic Epidemiology Study (VAGES). Basal fasting RNA was extracted from adipose tissue biopsies from a subset of 75 unrelated individuals, and gene expression data generated on the Illumina BeadArray platform. The number of gene probes with significant expression above baseline was approximately 31,000. We performed multiple regression analysis of all probes with 15 metabolic traits. Adipose tissue had 3,012 genes significantly associated with the traits of interest (false discovery rate, FDR ≤ 0.05). The significance of gene expression changes was used to select 52 genes with significant (FDR ≤ 10(-4)) gene expression changes across multiple traits. Gene sets/Pathways analysis identified one gene, alcohol dehydrogenase 1B (ADH1B) that was significantly enriched (P < 10(-60)) as a prime candidate for involvement in multiple relevant metabolic pathways. Illumina BeadChip derived ADH1B expression data was consistent with quantitative real time PCR data. We observed significant inverse correlations with waist circumference (2.8 x 10(-9)), BMI (5.4 x 10(-6)), and fasting plasma insulin (P < 0.001). These findings are consistent with a central role for ADH1B in obesity and insulin resistance and provide evidence for a novel genetic regulatory mechanism for human metabolic diseases related to these traits.

Circulating miR-192 and miR-193b are markers of prediabetes and are modulated by an exercise intervention

CONTEXT

Diabetes is frequently diagnosed late, when the development of complications is almost inevitable, decreasing the quality of life of patients. However, early detection of affected individuals would allow the implementation of timely and effective therapies.

OBJECTIVE

Here we set to describe the profile of circulating microRNAs (miRNAs) in prediabetic patients with the intention of identifying novel diagnostic and therapeutic tools.

DESIGN

We used real-time RT-PCR to measure the abundance of 176 miRNAs in serum of a cohort of 92 control and prediabetic individuals with either impaired fasting glucose or impaired glucose tolerance, as well as newly diagnosed diabetic patients. We validated the results in a second cohort of control and prediabetic subjects undergoing a therapeutic exercise intervention, as well as in a mouse model of glucose intolerance.

RESULTS

We identified two miRNAs, miR-192 and miR-193b, whose abundance is significantly increased in the prediabetic state but not in diabetic patients. Strikingly, these miRNAs are also increased in plasma of glucose-intolerant mice. Moreover, circulating levels of miR-192 and miR-193b return to baseline in both prediabetic humans and glucose-intolerant mice undergoing a therapeutic intervention consisting in chronic exercise, which succeeded in normalizing metabolic parameters.

CONCLUSIONS

Our data show that the pattern of circulating miRNAs is modified by defects in glucose metabolism in a similar manner in mice and humans. This circulating miRNA signature for prediabetes could be used as a new diagnostic tool, as well as to monitor response to intervention.

Impact of variants of the EXT2 gene on Type 2 diabetes and its related traits in the Chinese han population

PURPOSE/AIM OF THE STUDY

Exostosin 2 (EXT2) is involved in early pancreatic development and the regulation of insulin synthesis. In this study, we aim to evaluate the contribution of EXT2 to the genetic pathogenesis of type 2 diabetes and its related traits in the Chinese population.

MATERIALS AND METHODS

A case-control study in a Chinese Han population was conducted that included 4766 patients with type 2 diabetes and 4596 control subjects from 14 different regions of China. Three single nucleotide polymorphism (SNP), rs3740878, rs11037909 and rs1113132, in the EXT2 gene were genotyped using the Illumina GoldenGate Genotyping assay.

RESULTS

After adjusting for sex, age and body mass index, logistic regression analysis revealed that the EXT2 gene had no association with type 2 diabetes using an additive genetic model [rs3740878 (Odds Ratio (OR) = 0.996, 95% confidence interval (CI) 0.928-1.069, p = 0.910), rs11037909 (OR = 1.003, 95%CI 0.933-1.078, p = 0.931), and rs1113132 (OR = 0.993, 95% CI 0.925-1.065, p = 0.842)]. None of these SNPs were associated with beta cell function as determined using the baseline disposition index, early phase insulin secretion and Oral Glucose Tolerance Test (OGTT) total disposition index.

CONCLUSIONS

Our study suggests that the EXT2 gene might not have a major role in the development of type 2 diabetes in the Chinese population.

Enhanced insulin sensitivity and acute regulation of metabolic genes and signaling pathways after a single electrical or manual acupuncture session in female insulin-resistant rats

AIM

To compare the effect of a single session of acupuncture with either low-frequency electrical or manual stimulation on insulin sensitivity and molecular pathways in the insulin-resistant dihydrotestosterone-induced rat polycystic ovary syndrome (PCOS) model. Both stimulations cause activation of afferent nerve fibers. In addition, electrical stimulation causes muscle contractions, enabling us to differentiate changes induced by activation of sensory afferents from contraction-induced changes.

MATERIALS AND METHODS

Control and PCOS rats were divided into no-stimulation, manual-, and electrical stimulation groups and insulin sensitivity was measured by euglycemic hyperinsulinemic clamp. Manually stimulated needles were rotated 180° ten times every 5 min, or low-frequency electrical stimulation was applied to evoke muscle twitches for 45 min. Gene and protein expression were analyzed by real-time PCR and Western blot.

RESULTS

The glucose infusion rate (GIR) was lower in PCOS rats than in controls. Electrical stimulation was superior to manual stimulation during treatment but both methods increased GIR to the same extent in the post-stimulation period. Electrical stimulation decreased mRNA expression of Adipor2, Adrb1, Fndc5, Erk2, and Tfam in soleus muscle and increased ovarian Adrb2 and Pdf. Manual stimulation decreased ovarian mRNA expression of Erk2 and Sdnd. Electrical stimulation increased phosphorylated ERK levels in soleus muscle.

CONCLUSIONS

One acupuncture session with electrical stimulation improves insulin sensitivity and modulates skeletal muscle gene and protein expression more than manual stimulation. Although electrical stimulation is superior to manual in enhancing insulin sensitivity during stimulation, they are equally effective after stimulation indicating that it is activation of sensory afferents rather than muscle contraction per se leading to the observed changes.

Obesity has an interactive effect with genetic variation in the activating transcription factor 6 gene on the risk of pre-diabetes in individuals of Chinese Han descent

Endoplasmic reticulum (ER) stress is one of the contributing factors to the development of β-cell failure in type 2 diabetes. ER stress response through ATF6 has been shown to play an important role in insulin resistance and pancreatic β-cell function. We investigated whether genetic polymorphisms in ATF6 were associated with the risk of pre-diabetes in a Chinese Han population, and whether they had a synergistic effect with obesity. Our samples included 828 individuals who were diagnosed as pre-diabetic, and 620 controls. The minor allele A at rs2340721 was associated with increased risk for pre-diabetes(p = 0.013), and this association was still significant after adjusting for gender, age, body mass index (BMI), and waist-hip ratio(p' = 0.011). BMI, treated as a continuous variable, and rs2340721 had an interactive effect on pre-diabetic risk(p for interaction = 0.003, β = 0.106). Carriers of GG at rs7522210 were also at a higher risk compared to non-carriers (OR = 1.390, 95%CI:1.206-1.818, p = 0.013, adjusted OR' = 1.516, 95%CI:1.101-2.006, p' = 0.006). GG homozygotes had increased fasting blood glucose (FBG) levels(GG vs CX: 5.6 ± 0.52 vs 5.5 ± 0.57 mmol/L, p = 0.016), lower insulin levels (0,30,120 minutes after glucose load) (p < 0.05), and reduced areas under the insulin curve than non-carriers(GG vs CX:67.3(44.2-102.3) vs 73.1(49.4-111.4), p = 0.014). rs10918270 was associated with FBG, and rs4657103 with 2 hour glucose levels after a 75 g glucose load. We also identified a haplotype of TTAG composed of rs4657103, rs2134697, rs2340721, and rs12079579, which was associated with pre-diabetes. The genetic variation in ATF6 is associated with pre-diabetes and has interactive effects with BMI on pre-diabetes in the Chinese Han population.

Serum miR-23a, a potential biomarker for diagnosis of pre-diabetes and type 2 diabetes

MicroRNAs (miRNAs) play a crucial role in the pathogenesis of type 2 diabetes (T2D); they regulate several metabolic pathways including insulin secretion, glucose homeostasis, so their potential as biomarkers of diagnosis and prognosis has became increasingly appreciated. In this study, we explore serum miRNA profiles in T2D patients. A total of ten candidate miRNAs were identified by Solexa sequencing scanning and followed by a stem-loop quantitative reverse transcription PCR (qRT-PCR) to assess these candidate serum miRNAs. The results of qRT-PCR assessment revealed low serum levels of miR-23a, let-7i, miR-486, miR-96, miR-186, miR-191, miR-192, and miR-146a in T2D. Except for significantly lower in T2D and pre-diabetes patients compared with normal glucose tolerance (NGT) controls (P = 2.87E-05 and P = 3.75E-02), the levels of miR-23a demonstrated also significant decline in T2D patients compared with pre-diabetes patients (P = 1.06E-02). This marker yielded an AUC of 0.835 (95 % CI 0.717-0.954). At a cutoff value of 1.645, the sensitivity was 79.2 % and the specificity was 75.0 % in discriminating T2D patients from NGT normal controls. These results revealed that serum miR-23a was a valuable biomarker for early detection of T2D and pre-diabetes with NGT.