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Background: The superior effects of gastric bypass surgery in preventing cardiovascular diseases compared with sleeve gastrectomy are well-established. However, whether these effects are independent of weight loss is not known., Methods: In this retrospective cohort study, we compared the change in cardiometabolic risks of 1073 diabetic patients undergoing Roux-en-Y gastric bypass (RYGB) (n = 265), one-anastomosis gastric bypass (OAGB) (n = 619), and sleeve gastrectomy (SG) (n = 189) with equivalent weight loss from the Min-Shen General Hospital. Propensity score-weighting, multivariate regression, and matching were performed to adjust for baseline differences., Results: After 12 months, OAGB and, to a lesser extent, RYGB exhibited superior effects on glycemic control compared with SG in patients with equivalent weight loss. The effect was significant in patients with mild-to-modest BMI reduction but diminished in patients with severe BMI reduction. RYGB and OAGB had significantly greater effects in lowering total and low-density lipoprotein cholesterol than SG, regardless of weight loss. The results of matching patients with equivalent weight loss yielded similar results. The longer length of bypassed biliopancreatic (BP) limbs was correlated with a greater decrease in glycemic levels, insulin resistance index, lipids, C-reactive protein (CRP) levels, and creatinine levels in patients receiving RYBG. It was correlated with greater decreases in BMI, fasting insulin, insulin resistance index, and C-reactive protein levels in patients receiving OAGB., Conclusion: Diabetic patients receiving OAGB and RYGB had lower glucose and cholesterol levels compared with SG independent of weight loss. Our results suggest diabetic patients with cardiovascular risk factors such as hypercholesterolemia to receive bypass surgery., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Distinct tissue-specific mechanisms mediate insulin action in fasting and postprandial states. Previous genetic studies have largely focused on insulin resistance in the fasting state, where hepatic insulin action dominates. Here we studied genetic variants influencing insulin levels measured 2 h after a glucose challenge in >55,000 participants from three ancestry groups. We identified ten new loci (P < 5 × 10 -8 ) not previously associated with postchallenge insulin resistance, eight of which were shown to share their genetic architecture with type 2 diabetes in colocalization analyses. We investigated candidate genes at a subset of associated loci in cultured cells and identified nine candidate genes newly implicated in the expression or trafficking of GLUT4, the key glucose transporter in postprandial glucose uptake in muscle and fat. By focusing on postprandial insulin resistance, we highlighted the mechanisms of action at type 2 diabetes loci that are not adequately captured by studies of fasting glycemic traits., (© 2023. The Author(s), under exclusive licence to Springer Nature America, Inc.)

Background/purpose: Hypertension is a risk factor of incident diabetes. In 2017, the ACC/AHA updated the definition of hypertension to above 130/80 mmHg, while the 2018 ESC/ESH guideline and the JNC7 criteria remained the cutoff of 140/90 mmHg. This study was aimed to investigate how different cutoffs of hypertension affect the association of hypertension to incident diabetes and the progression of insulin resistance., Methods: A total of 1177 subjects without diabetes at baseline were followed for 4.5 years. Diabetes was diagnosed by the results of oral glucose tolerance tests and hemoglobin A1c, or if anti-diabetic agents were used., Results: Hypertension by both criteria was associated with incident diabetes. Change of HOMA2-IR every 5 years (ΔHOMA2-IR/5 yr) was higher in subjects with hypertension than those without (adjusted p = 0.044). Subjects with treated hypertension had the highest risk of diabetes (HR 2.98, p < 0.001) and ΔHOMA2-IR/5 yr, compared with subjects with normal blood pressure. However, the associations of hypertension, HR of incident diabetes and ΔHOMA2-IR/5 yr were attenuated by the 2017 ACC/AHA criteria, as compared with that by the JNC7 and 2018 ESC/ESH criteria., Conclusion: Hypertension by both criteria is associated with incident diabetes and accelerated progression of insulin resistance, and the associations are attenuated by the 2017 ACC/AHA criteria., (Copyright © 2021 Formosan Medical Association. Published by Elsevier B.V. All rights reserved.)

Metformin improves mitochondrial function and enhances autophagy of T helper 17 cells, leading to decreased inflammation. This highlights the importance of metabolic modulation of immune cells., (© 2021 The Authors. Journal of Diabetes Investigation published by Asian Association for the Study of Diabetes (AASD) and John Wiley & Sons Australia, Ltd.)

Aims: Insulin resistance (IR) changes over time during the development of type 2 diabetes. Some reports showed that obesity was associated with progression of IR. However, no study has explored if change of IR predicts incident diabetes, and no study has investigated other factors associated with the change., Methods: In this study, 1184 subjects without diabetes at baseline were enrolled in 2006-2016 with a median follow-up period of 4.5 years. Diabetes was diagnosed by oral glucose tolerance test and hemoglobin A1c, or if anti-diabetic agents were used. HOMA2-IR and ISI 0,120 were used to estimate IR., Results: The annual changes of HOMA2-IR(ΔHOMA2-IR/year) and ISI 0,120 (ΔISI 0,120 /year) were associated with BMI, waist circumference(WC), glucose, HbA1c, triglyceride and HDL-cholesterol. Subjects with pre-diabetes or metabolic syndrome were associated with a more rapid increase of IR. ΔHOMA2-IR/year and ΔISI 0,120 /year were correlated with annual changes of BMI and WC. The hazard ratios for ΔHOMA2-IR/year and ΔISI 0,120 /year to predict incident diabetes were 1.39 (95% CI 1.22-1.59, p < 0.001) and 0.13 (95% CI 0.09-0.19, p < 0.001) in adjusted models, respectively., Conclusions: Change of IR can be used as a surrogate marker of incident diabetes. The progression of IR is an important pathophysiologic link between risk factors and the incidence of diabetes., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Objectives: Growth arrest-specific 6 (Gas6), a vitamin K-dependent protein, has been implicated in systemic inflammation, obesity, and insulin resistance (IR). Data from recent studies suggest that polymorphisms in the Gas6 gene are associated with cardiovascular disorders and type 2 diabetes (T2D). However, the association of Gas6 gene variants with obesity, IR, and T2D development has not been explored., Materials and Methods: Four common single nucleotide polymorphisms (SNPs) in the Gas6 gene were genotyped in 984 participants from the Stanford Asia-Pacific Program for Hypertension and Insulin Resistance (SAPPHIRe) family cohort. An insulin suppression test was performed to determine IR based on steady-state plasma glucose (SSPG). Associations between IR indices and obesity, and SNP genotypes, based on previously-reported data for this cohort (Phase I), were analyzed. In the present follow-up study (Phase II), the effects of gene variants of Gas6 on the progression to T2D were explored in individuals who were free of T2D in Phase I. The mean follow-up period for Phase II was 5.7 years., Results: The mean age of the study population in Phase I was 49.5 years and 16.7% of individuals developed T2D during follow-up. After adjusting for covariates, three SNPs (rs8191973, rs8197974, and rs7323932) were found to be associated with SSPG levels (p = 0.007, p = 0.03, and p = 0.011, respectively). This association remained significant after multiple testing and showed a significant interaction with physical activity for SNP rs8191973. However, no other significant correlations were observed between Gas6 polymorphisms and other indices of IR or obesity. A specific haplotype, AACG (from rs8191974, rs7323932, rs7331124, and rs8191973), was positively associated with SSPG levels (p = 0.0098). None of the polymorphisms were associated with an increased risk of T2D development., Conclusions: Our results suggest that Gas6 gene variants are associated with IR, although their effects on subsequent progression to T2D were minimal in this prospective Asian cohort.

Background: This study investigated the differences in exercise self-efficacy, compliance, and effectiveness of home-based exercise in individuals with and without metabolic syndrome (MetS)., Methods: One hundred and ten individuals at risk for diabetes participated in this study. Subjects were categorized into individuals with MetS and individuals without MetS. Metabolic risk factors and exercise self-efficacy were evaluated for all subjects before and after 3 months of home-based exercise. Univariate analysis of variance was used to compare the effectiveness of a home-based exercise program between individuals with and without MetS., Results: The home-based exercise program improved body mass index and lipid profile in individuals at risk for diabetes, regardless of MetS status at baseline. Individuals without MetS had higher exercise self-efficacy at baseline and performed greater exercise volume compared with individuals with MetS during the intervention. The increased exercise volume in individuals without MetS may contribute to their better control of insulin resistance than individuals with MetS. Furthermore, baseline exercise self-efficacy was correlated with exercise volume executed by subjects at home., Conclusions: We conclude that home-based exercise programs are beneficial for individuals at risk for diabetes. However, more intensive and/or supervised exercise intervention may be needed for those with MetS.

In this paper we try to define insulin resistance (IR) precisely for a group of Chinese women. Our definition deliberately does not depend upon body mass index (BMI) or age, although in other studies, with particular random effects models quite different from models used here, BMI accounts for a large part of the variability in IR. We accomplish our goal through application of Gauss mixture vector quantization (GMVQ), a technique for clustering that was developed for application to lossy data compression. Defining data come from measurements that play major roles in medical practice. A precise statement of what the data are is in Section 1. Their family structures are described in detail. They concern levels of lipids and the results of an oral glucose tolerance test (OGTT). We apply GMVQ to residuals obtained from regressions of outcomes of an OGTT and lipids on functions of age and BMI that are inferred from the data. A bootstrap procedure developed for our family data supplemented by insights from other approaches leads us to believe that two clusters are appropriate for defining IR precisely. One cluster consists of women who are IR, and the other of women who seem not to be. Genes and other features are used to predict cluster membership. We argue that prediction with "main effects" is not satisfactory, but prediction that includes interactions may be.

Type 2 diabetes is frequently associated with metabolic syndrome (MetS). Insulin resistance (IR) is thought to be the underlying pathophysiology of MetS. The purpose of this study is to examine the association of MetS with IR and beta cell function. This is a cross-sectional study in NHANES 1999-2000 participants who were at least 18 years old, including 911 non-Hispanic whites (NHW), 398 non-Hispanic blacks (NHB), and 595 Mexican-Americans (MA). MetS was defined based on the revised ATP III. IR and beta cell function were calculated using homeostasis model assessment (HOMA-IR and HOMA-B). The high-risk tertile was defined as the highest HOMA-IR and lowest HOMA-B. The odds ratio (OR) was calculated against the other two tertiles. The relationship of HOAM-IR and HOMA-B with the components of MetS was also examined. IR was a risk factor of MetS in all three ethnic groups (OR 4.17-12.01, P < 0.0001). Fasting glucose, triglycerides, and HDL cholesterol were associated with IR (P < 0.001) and correlated with HOMA-IR (P < 0.001), while inconsistent results were noted in blood pressure and waist circumference among three racial/ethnic groups. However, in the MetS subjects, 32 % of NHW, 28 % of NHB, and 44 % of MA were not in the IR tertile and in the IR subjects, 25 % of NHW, 36 % NHB, and 30 % of MA did not have MetS. No relationship was found between beta cell function and MetS. Although IR is a risk factor for MetS, IR is neither necessary nor required for MetS.

The deadenylase nocturnin (Noc, Ccrn4l) has been recently found to regulate lipid metabolism and to control preadipocyte differentiation. Here, we showed that among the five deadenylases tested, Noc and Pan2 exhibited a biphasic expression which is out of phase to each other during adipocyte differentiation of 3T3-L1 cells. The expression levels of other deadenylases, including Parn, Ccr4, and Caf1, were relatively unchanged or reduced. The immediate early expressed Noc during 3T3-L1 adipogenesis was involved in regulating mitotic clonal expansion (MCE) and cyclin D1 expression, as demonstrated in Noc-silenced 3T3-L1 cells and Noc(-/-) primary mouse embryonic fibroblasts (MEFs). Transcriptional profiling of Noc-depleted 3T3-L1 adipocytes revealed that most of the differentially expressed genes were related to cell growth and proliferation. In human adipose tissue, NOC mRNA level negatively associated with both fasting serum insulin and homeostasis model assessment of insulin resistance, and positively associated with both adiponectin mRNA levels and circulating adiponectin levels. Taken together, these results suggest the role of Noc in the modulation of early adipogenesis as well as systemic insulin sensitivity.

Prostaglandins are potent modulators of insulin sensitivity. We systemically evaluated the association of 61 tag single-nucleotide polymorphisms (SNP) in 14 genes involved in prostaglandin metabolism with type 2 diabetes. Among all genotyped SNPs, rs10483032 in the CBR3 (carbonyl reductase 3) gene, which encodes for an enzyme converting prostaglandin E(2) to prostaglandin F2(α), was associated with type 2 diabetes in 760 type 2 diabetic cases and 760 controls (stage-1 study) (P = 2.0 × 10(-4)). The association was validated in 1,615 cases and 1,162 controls (stage-2 study) (P = 0.009). The A allele at rs10483032 was associated with increased risk of type 2 diabetes (odds ratio = 1.29; 95% confidence interval = 1.14-1.47; combined P < 0.0001). The association was externally validated in the Finland-United States Investigation of NIDDM Genetics (FUSION) study (P = 3.7 × 10(-4)). The risk A allele was associated with higher homeostasis model assessment of insulin resistance (HOMA-IR) in 1,012 non-diabetic controls and 1,138 non-diabetic subjects from the Stanford Asia-Pacific Program for Hypertension and Insulin Resistance (SAPPHIRe) family study. CBR3 gene expression in human abdominal adipose tissue was negatively associated with fasting insulin and HOMA-IR. CBR3 gene expression increased during differentiation of 3T3-L1 preadipocytes into adipocytes. Knockdown of CBR3 in 3T3-L1 preadipocytes enhanced adipogenesis and peroxisome proliferator-activator receptor-γ response element reporter activity. Our results indicated that genetic polymorphism in the CBR3 gene conferred risk of type 2 diabetes and insulin resistance in Chinese. The association was probably mediated through modulation of adipogenesis.

TCF7L2 genetic variants were associated with progression to type 2 diabetes in Europeans. However, the role of TCF7L2 in type 2 diabetes remained uncertain in Chinese. Seventeen tag single nucleotide polymorphisms were genotyped in 1,094 subjects of Chinese origin from the Stanford Asia-Pacific Program for Hypertension and Insulin Resistance family study. At baseline, the rs7903146 T allele in the exon 4 linkage disequilibrium (LD) block were associated with lower insulinogenic index at 60 min (P = 0.01), while the rs290481 G allele near the 3' end was associated with higher 2-h post-challenge glucose (P = 0.003) and insulin concentration (P = 0.02), elevated systolic (P = 0.01) and diastolic blood pressure (P = 0.006), lower waist circumference (P = 0.01), and increased steady-state plasma glucose (SSPG) concentration measured with modified insulin suppression test (P = 0.02). Over an average follow-up period of 5.43 years, participants with the rs7903146 T allele or variants in the same LD block, but not those with the rs290481 G allele, were more likely to progress to diabetes (hazard ratio = 2.61, 95% confidence interval, 1.27-5.39, P = 0.009) than were non-carriers. TCF7L2 gene expression was inversely associated with SSPG in human visceral (r = -0.73, P = 0.006) and subcutaneous adipose tissue (r = -0.62, P = 0.03). TCF7L2 may exert pleiotropic effects on insulin secretion or insulin resistance. However, only variants associated with impaired beta-cell function predict progression to diabetes in Chinese.

Visfatin/pre-B-cell colony-enhancing factor (PBEF)/nicotinamide phosphoribosyltransferase (Nampt) has been proposed as an insulin-mimicking adipocytokine predominantly secreted from visceral adipose tissue (VAT) and correlated with obesity. However, recent evidence challenged this proposal and instead suggested visfatin/PBEF/Nampt as a proinflammatory cytokine. The study aimed to examine whether visfatin/PBEF/Nampt was predominantly expressed in VAT and was correlated with obesity. The relationship of visfatin/PBEF/Nampt gene expression in adipose tissues with proinflammatory gene expression and metabolic phenotypes was also examined. The relative messenger RNA (mRNA) levels of visfatin/PBEF/Nampt, macrophage-specific marker CD68, and proinflammatory genes were measured in paired abdominal VAT and subcutaneous adipose tissues (SAT) and from 53 nondiabetic adults using quantitative real-time polymerase chain reaction. Fasting glucose, insulin, triglyceride, cholesterol, and uric acid levels were measured; and systemic insulin sensitivity was quantified with modified insulin suppression tests. There was no difference in visfatin/PBEF/Nampt mRNA levels between VAT and SAT, and neither was associated with measures of obesity. Visfatin/PBEF/Nampt mRNA levels were strongly correlated with proinflammatory gene expression including CD68 and tumor necrosis factor-alpha gene in both VAT and SAT. The VAT and SAT visfatin/PBEF/Nampt mRNA expressions were positively correlated with steady-state plasma glucose concentrations measured with modified insulin suppression tests, a direct measurement of systemic insulin resistance (r = 0.42, P = .03 and r = 0.44, P = .03, respectively). The VAT visfatin/PBEF/Nampt mRNA expression was also positively correlated with fasting triglyceride (r = 0.42, P = .002) and total cholesterol levels (r = 0.37, P = .009). Visfatin/PBEF/Nampt is not predominantly secreted from VAT and is not correlated with obesity. Our findings suggest that visfatin/PBEF/Nampt is a proinflammatory marker of adipose tissue associated with systemic insulin resistance and hyperlipidemia.

Objectives: The effect of TCF7L2 rs7903146 on glucose homeostasis is considered primarily due to impaired insulin secretion in European populations. Because we previously demonstrated that TCF7L2 rs290487 near the 3' end of TCF7L2 was significantly associated with type 2 diabetes (T2D) in Taiwanese subjects, we aimed to investigate potential mechanisms underlying the associations of rs290487 with T2D., Methods: Eighteen single nucleotide polymorphisms (SNPs) were tested for association with glucose/insulin homeostasis as well as other quantitative metabolic phenotypes using the quantitative transmission disequilibrium test in 525 Taiwanese adolescent twin-pairs and siblings. The results were further replicated in 116 nondiabetic normotensive Caucasian young adults., Results: Among the 18 SNPs, rs290487 C allele was significantly associated with higher 60-, 90-, and 120-min glucose concentrations (P = 0.001, 0.01, and 0.02, respectively); higher 60- and 90-min insulin concentrations (P = 0.01 and 0.01, respectively); and a lower insulin sensitivity index (P = 0.04). No association was found for rs290487 with measures of insulin secretion. The rs290487 C allele was also associated with HOMA-IR (P = 0.005) and insulin sensitivity index (P = 0.01) in Caucasian young adults. Another SNP, rs10749127 C allele located in intron 4, was also associated with features of the metabolic syndrome, including elevated systolic (P = 0.02) and diastolic (P = 2.0 x 10(-4)) blood pressure, triglycerides (P = 7.0 x 10(-4)), and uric acid (P = 0.03). In a meta-analysis, the rs290487 C allele was confirmed to be associated with an increased risk of T2D (odds ratio, 1.11; 95% confidence interval, 1.03-1.19; P = 0.005) across East Asian populations., Conclusions: These findings support an important role for T2D risk-conferring gene TCF7L2 in insulin resistance in both Taiwanese and Caucasian youth and underscore the emerging role of Wnt signaling in insulin resistance.

Background and Purpose: Physical inactivity has been well documented as a risk factor for type 2 diabetes. Previous studies measured the level of physical activity either with questionnaires or with direct measurements of maximum oxygen uptake. However, questionnaires are patient-report measures, and methods for obtaining direct maximum oxygen uptake measurements often are not available clinically. The purpose of this study was to investigate whether clinical measurement of health-related physical fitness with a simple test battery can predict insulin resistance, a precursor of type 2 diabetes, in people at risk for diabetes., Subjects and Methods: A total of 151 volunteers with at least one diabetes risk factor (overweight, hypertension, dyslipidemia, family history, impaired glucose tolerance, gestational diabetes, or delivering a baby weighing more than 4.0 kg) were recruited. Insulin resistance (as determined with the homeostasis model assessment of insulin resistance [HOMA-IR]), physical fitness (including body composition, as determined with the body mass index and waist circumference), muscle strength (handgrip strength [force-generating capacity]), muscle endurance (sit-up test), flexibility (sit-and-reach test), and cardiorespiratory endurance (step test) were measured, and a physical activity questionnaire was administered. Backward regression analysis was used to build the prediction models for insulin resistance from components of physical fitness and physical activity., Results: Body mass index, muscle strength, and cardiorespiratory fitness predicted HOMA-IR in men (adjusted R(2)=.264). In women, age, waist circumference, and cardiorespiratory fitness were the predictors of HOMA-IR (adjusted R(2)=.438)., Discussion and Conclusion: Clinical measures of physical fitness can predict insulin resistance in people at risk for diabetes. The findings support the validity of clinical measures of physical fitness for predicting insulin resistance in people at risk for diabetes.

In this ongoing longitudinal study of adolescent twins/sibling pairs and their parents in Taipei, we aimed to investigate the genetic and environmental influences on adolescent behavioral development, metabolic risk factors, and the associations between the two. Special focus is on anxious depression, metabolic profile, and hormonal factors such as cortisol and leptin. The first wave of assessment was completed during the period of 2002 to 2005 and included 192 twin pairs, 6 triplets, 56 sibling pairs and their first-degree relatives (484 parents and 142 siblings). We are currently in the process of a second wave assessment as follow-up. Dimensional psychological assessments using self-report questionnaires, as well as categorical assessments based on semistructured clinical interviews, were performed. All subjects received a 2-hour oral glucose tolerance test at the examination site. The metabolic phenotypes including body mass index, blood pressure, levels of glucose, insulin, and lipid profile as well as related hormonal levels were measured. Zygosity was determined using DNA, except for a few twins whose DNA was not available. Such a combination of detailed psychological assessments and metabolic function tests is expected to help shed light on the interrelation of psychological well-being and metabolic functioning.

Objectives: Alternation in lipid metabolism can affect both insulin sensitivity and beta-cell function. Apolipoprotein A5 (APOA5) is an important determinant of lipid metabolism. The impact of the APOA5 gene on insulin sensitivity and beta-cell function has not been examined., Methods: We examined the influence of 2 amino acid polymorphisms (V150M and G182C) in the APOA5 gene on insulin sensitivity and beta-cell function in 67 glucose-tolerant white subjects. Insulin sensitivity index (ISI) and first- and second-phase insulin responses (1stIR and 2ndIR) were assessed using a hyperglycemic clamp technique., Results: We identified 59 VV and 8 VM subjects, and none had either the GC or CC genotype. Although no association was found with fasting lipid profile and plasma glucose concentrations during oral glucose tolerance test, the V150M was associated with higher 1stIR (P = 0.0010) and 2ndIR (P = 0.0016) and lower ISI (P = 0.0135). The associations of this polymorphism with 1stIR (P = 0.0081) and 2ndIR (P = 0.0087) were independent of sex, age, and body mass index, but not ISI., Conclusions: The V150M polymorphism had an independent influence on 1stIR and 2ndIR. Although the biologic consequence of this polymorphism remains to be determined, the V150M polymorphism in the APOA5 gene is a genetic marker for beta-cell function.

Objective: Although the role of the leptin receptor (LEPR) in obesity is well recognized, its role in insulin sensitivity remains unknown., Design: This was a cross-sectional study to investigate the impact of the Q223R polymorphism of the LEPR gene on insulin sensitivity., Methods: Sixty-seven glucose-tolerant Caucasians were enrolled. The insulin sensitivity index and glucose clearance were measured using a hyperglycemic clamp. Genomic DNA was extracted for genotyping., Results: We identified 20 QQ, 31 QR, and 16 RR subjects. The three genotypic groups were similar in age, gender distribution, body mass index, waist-hip ratio, and blood pressure, but differed in the insulin sensitivity index (P=0.0180) and in glucose clearance (P=0.0220). Multivariate analyses showed that the Q223R polymorphism was independently associated with the insulin sensitivity index (P=0.0317) and glucose clearance (P=0.0436). A trend of increasing low density lipoprotein cholesterol concentration was also observed (P=0.0447)., Conclusion: We have reported the first association of the Q223R polymorphism of the LEPR gene with insulin resistance.

Objective: To study the effect of body composition and adiponectin on insulin resistance and beta-cell function in schoolchildren during puberty., Research Design and Methods: Plasma adiponectin level and its relationships with insulin sensitivity and beta-cell function were analyzed in 500 randomly recruited nondiabetic Taiwanese schoolchildren (245 boys and 255 girls) aged 6-18 years in a national survey program for diabetes in 1999. Insulin resistance and beta-cell function were evaluated by homeostasis model assessment (HOMA). Plasma adiponectin concentrations were determined with radioimmunoassay., Results: Plasma glucose levels remained stable, whereas insulin resistance increased with a compensatory rise in beta-cell function during this period. A transient drop of adiponectin level with a trough at 10-12 years was found in boys but not in girls. This pubertal drop of adiponectin levels in boys coincides with the sharp rise in testosterone concentration. A negative correlation between testosterone levels and adiponectin concentration was also noted in boys (r = -0.142, P = 0.032). Plasma adiponectin levels correlated inversely with relative body weight, fasting insulin concentrations, and insulin resistance index by HOMA in boys aged 15-18 years and in girls aged 11-14 years. No association was observed between adiponectin levels and beta-cell function by HOMA., Conclusions: There is a transient drop in the level of adiponectin during male puberty, correlated with the increase in testosterone level in boys. Plasma adiponectin levels were inversely correlated with obesity and insulin resistance in boys and girls during the pubertal period.

The clustering between hypertension and other metabolic abnormalities related to insulin resistance syndrome (IRS) has been investigated in cross-sectional and prospective studies. Offspring studies have revealed that the clustering characteristics of IRS have familial components. However, it is not known whether the clustering also occurs in siblings (sibs) with different levels of blood pressure (BP). In addition, the genetic susceptibility accounting for the clustering in hypertensive families has not been determined. Siblings with Japanese or Chinese ancestry and having either similar BP levels (concordant sibs) or different BP levels (discordant sibs) were recruited. The delta method and variance component model were applied to analyze the differences in metabolic variables between hypertension (HTN) and low BP (LBP) sibs, and to compute the polygenic heritabilities for these metabolic variables and insulin sensitivity. After adjustment for age, gender and body mass index (BMI), HTN (n=393) sibs had higher levels of triglyceride (p < 0.0001), VLDL-cholesterol (p<0.0001), fasting insulin (p < 0.05), and homeostasis model assessment of insulin resistance (HOMAir) (p < 0.05) than LBP sibs (n = 389), but there were no differences in fasting glucose or high density lipoprotein (HDL)-cholesterol. The HTN sibs also had higher plasma glucose and insulin levels at 2 h after 75 g oral glucose loading (p<0.001 and p<0.01, respectively). The heritability estimates for fasting glucose, fasting insulin and HOMAir were 0.58, 0.43 and 0.46, respectively; for triglyceride, HDL-cholesterol, and BMI they were 0.60, 0.63 and 0.54, respectively. In hypertensive families, sibs with extreme levels of BP have significant differences in IRS-associated metabolic variables. The clustering characteristics and the significance of heritability estimation for these metabolic variables indicate that IRS is familial in nature and heritable in Chinese and Japanese hypertensive families.

Angiopoietin-like 4 (ANGPTL4) is an endogenous inhibitor of lipoprotein lipase that modulates lipid levels, coronary atherosclerosis risk, and nutrient partitioning. We hypothesize that loss of ANGPTL4 function might improve glucose homeostasis and decrease risk of type 2 diabetes (T2D). We investigate protein-altering variants in ANGPTL4 among 58,124 participants in the DiscovEHR human genetics study, with follow-up studies in 82,766 T2D cases and 498,761 controls. Carriers of p.E40K, a variant that abolishes ANGPTL4 ability to inhibit lipoprotein lipase, have lower odds of T2D (odds ratio 0.89, 95% confidence interval 0.85-0.92, p = 6.3 × 10-10), lower fasting glucose, and greater insulin sensitivity. Predicted loss-of-function variants are associated with lower odds of T2D among 32,015 cases and 84,006 controls (odds ratio 0.71, 95% confidence interval 0.49-0.99, p = 0.041). Functional studies in Angptl4-deficient mice confirm improved insulin sensitivity and glucose homeostasis. In conclusion, genetic inactivation of ANGPTL4 is associated with improved glucose homeostasis and reduced risk of T2D.

The ALDH2 gene encodes the mitochondrial aldehyde dehydrogenase 2 (ALDH2), a critical enzyme involved in ethanol clearance through acetaldehyde metabolism. ALDH2 also catalyzes the metabolism of other bioreactive aldehydes, including propionaldehyde, butyraldehyde, and 4-hydroxykenals (4-HNE). Increased levels of 4-HNE in adipose tissue positively correlate with obesity and insulin resistance. However, it remains unclear whether ALDH2 is involved in regulation of adipocyte differentiation. Here, we found that ALDH2 protein levels were lower in white adipose tissue of high-fat diet-fed mice and ob/ob mice relative to lean mice. Knockdown of ALDH2 expression in 3T3-L1 preadipocytes caused an increase in intracellular 4-HNE, thereby attenuated adipocyte differentiation. By contrast, an ALDH2 activator, Alda-1, significantly accelerated adipogenesis, which was accompanied by an increase in adipogenic gene expression. Consistently, adipogenesis was reduced when protein kinase C ε (PKCε), an ALDH2 phosphorylating activator, was silenced in 3T3-L1 preadipocytes, whereas treatment with a PKCε agonist in 3T3-L1 preadipocytes enhanced adipogenesis. Whole-genome microarray profiling of Alda-1-treated cells demonstrated several upregulated transcripts encoding proteins involved in metabolism and the majority of these transcripts are for proteins involved in PPAR signaling pathways. Furthermore, PKCε-ALDH2 interaction alleviates 4-HNE induced aberrant PPARγ regulation on adipogenesis. Taken together, these results demonstrate that ALDH2 activation enhances adipogenesis and signaling pathways involving PPARγ. Thus, activation of PKCε-ALDH2 regulatory axis may be a therapeutic target for treating obesity and type 2 diabetes. [ABSTRACT FROM AUTHOR]

The peroxisome proliferator activated receptor (PPAR) γ2 is a transcription factor that has been shown to be involved in adipocyte differentiation, adipogenesis, and insulin sensitivity. To address the role of PPARγ2 in glucose homeostasis and insulin sensitivity, among many other objectives, we conducted a sibling-controlled association study in a multicenter program – the Stanford Asian-Pacific Program in Hypertension and Insulin Resistance (SAPPHIRe). Approximately 2525 subjects in 734 Chinese and Japanese families have been recruited from six field centers for SAPPHIRe. In total, 1702 subjects including parents and siblings from 449 families have been genotyped for PPARγ2, of which 328 families were Chinese and 121 Japanese. Only 88 subjects of the 1525 siblings screened for the P12A polymorphism were found to be carriers of the A variant, the most common variant of the PPARγ2 gene. A variant frequencies of the siblings were 4.27% in Chinese and 2.72% in Japanese. A sibling-controlled association study was performed through genetically discordant sibships (i.e., P/P genotype vs. P/A + A/A genotypes). Specifically, we examined whether there were differences in metabolic variables between the discordant siblings within families. In total, 88 subjects carrying either 1 or 2 A alleles had at least one sibling who was discordant for the P12A polymorphism, yielding a total of 180 individuals from 47 families for analyses, among which 92 siblings were homozygous for wild-type P allele. Siblings with the A variant tended to have lower levels of fasting plasma glucose (OG-10), and lower glucose levels at 60 min following oral glucose loading after adjusting for age, gender, and body mass index. Using a mixed model treating family as a random effect, we found that P12A polymorphism of the PPARγ2 gene contributes significantly to the variance in fasting plasma glucose, glucose level at 60 min, and insulin-resistance homeostasis model assessment. Our results suggest that within families siblings with the A variant in the PPARγ2 gene may be more likely to have better glucose tolerance and insulin sensitivity independent of obesity in Chinese and Japanese populations. [ABSTRACT FROM AUTHOR]

OBJECTIVE As type 2 diabetes results from an imbalance between insulin sensitivity and beta cell function, either or both may worsen with age. However, existing data are controversial on the effect of ageing on both insulin sensitivity and beta cell function. SUBJECTS AND DESIGN We enrolled 149 healthy, glucose tolerant and normotensive Caucasians (age 35 ± 1 years, body mass index 26.07 ± 0.44 kg/m2, waist-hip ratio 0.842 ± 0.009 cm/cm, mean ± standard error). A cross-sectional study was designed to examine the impact of age on insulin sensitivity and beta cell function. Their beta cell function (percentage B [%B]) and insulin sensitivity (percentage S [%S]) were estimated using the homeostasis model assessment. RESULTS Simple regression analysis revealed that %B declined with age (P = 0.008) while no relation was found between %S and age (P = 0.769). A stepwise regression analysis revealed that body mass index and diastolic blood pressure explained 14.7% of variation in %S, while age, waist-hip ratio, gender, and systolic blood pressure had no influence on %S. Age, body mass index and diastolic blood pressure together accounted for 21.7% of variation in %B, with age being an independent variable. CONCLUSIONS In the present study, we showed that beta cell function declined with age at a rate of about 1% per year. In contrast, insulin sensitivity was not affected by ageing. Our observations suggest that the age-related decline in glucose tolerance is primarily related to the loss of beta-cell function. [ABSTRACT FROM AUTHOR]

A correction to the article "Genetic variation in the carbonyl reductase 3 gene confers risk of type 2 diabetes and insulin resistance: A potential regulator of adipogenesis" that was published in the May 31, 2012 issue is presented.

Abstract: Objective: To evaluate short- (3months) and long-term (9months) effects of home-based exercise on adiponectin, exercise behavior and metabolic risk factors in middle-aged adults at diabetic risk. Methods: One hundred and thirty-five middle-aged adults (38 men, 97 women) with at least one diabetic risk factor were randomly assigned to either a home-based exercise group (Ex-group) or a usual care group (C-group). Outcome measures included plasma adiponectin, exercise self-efficacy, physical activity, and metabolic risk factors, as follows: insulin levels, insulin resistance by homeostasis model assessment (HOMA-IR), physical fitness, and components of metabolic syndrome. This study was conducted in metropolitan Taipei from 2004 to 2005. Results: The Ex-group had improvements in exercise self-efficacy (+2.5, p =0.01), body mass index (BMI) (−0.6kg/m2, p <0.001) and flexibility (+2.4cm, p <0.001) at 3-month follow-up and maintained BMI and flexibility at 9-month follow-up. The Ex-group exhibited significantly increased physical activity while the C-group exhibited decreased physical activity at 9-month follow-up (p <0.001). No intervention effect was found on adiponectin (p =0.64) or other outcome measures over time. Conclusions: Home-based exercise did not improve adiponectin levels, but significantly improved exercise behavior, and certain metabolic risk factors, with the effects maintained for 9-months in subjects with type 2 diabetic risk. [Copyright &y& Elsevier]

Abstract: Background: A previous study has reported that the Ile227 and Ala357 genetic variants of human urea transporter-2 (HUT2) were associated with blood pressure in males in Asian population. In this study, we aimed to investigate five known HUT2 genetic variants with metabolic syndrome (MetS) and its related traits in the Stanford Asia-Pacific Program for Hypertension and Insulin Resistance (SAPPHIRe) study cohort. Methods: Five HUT2 single nucleotide polymorphisms (SNPs) were selected and genotyped among 1791 subjects in the SAPPHIRe study cohort. We first computed allele frequency and performed Hardy–Weinberg equilibrium (HWE) test in controls for each SNP. Next, we tested genotype associations with metabolic syndrome using multiple generalized estimating equations (GEE) models with covariate adjustment. Furthermore, multi-marker and multi-trait association tests were carried out using FBAT program. To account for multiple testing, Bonferroni correction was applied in this study. Results: Among those 5 HUT2 SNPs, SNPs 1, 2 and 3 were significantly associated with MetS in the total sample and females, separately (9×10−4 ≤ p ≤0.04), but only the association between SNP 1 and MetS in females remained statistically significant after Bonferroni correction. When testing 5 SNPs simultaneously, significant associations were found with triglycerides (TG) (p =0.04). Likewise, significant multi-trait association (combining the data of waist circumference, TG, high density lipoprotein (HDL) cholesterol and fasting glucose together) was found with SNP 2 (p =0.04), but both results of multi-maker and multi-trait associations did not remain significant after multiple testing correction. Conclusion: The results have provided evidence that the HUT2 gene may play a certain role in developing MetS and its related traits in Asian population. Further investigation of the HUT2 gene influencing MetS and its related traits will be warranted. [Copyright &y& Elsevier]