The association of SNPs in ADIPOQ, ADIPOR1, and ADIPOR2 with insulin sensitivity in a cohort of adolescents and their parents

Association study between adiponectin gene variants, serum levels and the risk of type 2 diabetes in Tunisian women: Insights from BMI stratification

Although prior studies have shown that adiponectin synthesis is genetically determined and that its levels influence susceptibility to T2D, the results in this regard have been inconsistent. This study aims, to investigate the relationship between adiponectin gene variants with the risk of developing T2D among Tunisian women and in relation to their BMI status. A cohort of 491 Tunisian T2D women and 373 non-diabetic subjects participated in the study. Nine ADIPOQ variants namely rs16861194, rs17300539, rs266729, rs822395, rs822396, rs2241766, rs1501299, rs2241767 and rs3774261 were selected and genotyped using the TaqMan® SNP genotyping assay. Fasting serum adiponectin levels were quantified using ELISA. The results showed that only the rs17300539 variant exhibited a significant association with the risk of T2D. However, upon considering T2D group stratification based on BMI (normal weight [18-24.99 Kg/m2], overweight [25-29.99 Kg/m2] and obese [30-34.99 Kg/m2]), the ADIPOQ rs2241766 variant emerged as a contributing risk factor for increased BMI in obese women with T2D. Linear regression analysis revealed that the minor allele (A), (GA) and (AA) genotypes of rs17300539 as well as the (G) allele and (GG) genotype of rs2241766 were significantly associated with hypoadiponectinemia in T2D subjects. Two haplotypes namely GGCAATGAA and AGCCGTGGA, were identified as conferring a higher risk of T2D with the GGCAATGAA haplotype also correlating with hypoadiponectinemia. Our study underscores the importance of the rs17300539 variant and the GGCAATGAA haplotype in the risk of T2D and hypoadiponectinemia. Additionally, the presence of the rs2241766 variant highlights its association with 'diabesity' and hypoadiponectinemia among Tunisian T2D women.

Novel Loci (EIF4A2, ADIPOQ, TPRG1) for Triglyceride / High-density Lipoprotein Cholesterol Ratio Longitudinal Change (ΔTHR) among Subjects without Type 2 Diabetes: Evidence from the Long Life Family Study (LLFS) and the Framingham Heart Study (FHS) Offspring Cohort (OS)

Aims/hypothesis

Triglyceride (TG) /High density lipoprotein cholesterol (HDL-C) ratio (THR) represents a single surrogate predictor of hyperinsulinemia or insulin resistance that is associated with premature aging processes, risk of diabetes and increased mortality. To identify novel genetic loci for THR change over time (ΔTHR), we conducted genome-wide association study (GWAS) and genome-wide linkage scan (GWLS) among subjects of European ancestry who had complete data from two exams collected about seven years apart from the Long Life Family Study (LLFS, n=1384), a study with familial clustering of exceptional longevity in the US and Denmark.

Methods

Subjects with diabetes or using medications for dyslipidemia were excluded from this analysis. ΔTHR was derived using growth curve modeling, and adjusted for age, sex, field centers, and principal components (PCs). GWAS was conducted using a linear mixed model accounted for familial relatedness. Our linkage scan was built on haplotype-based IBD estimation with 0.5 cM average spacing.

Results

Heritability of ΔTHR was moderate (46%). Our GWAS identified a significant locus at the LPL (p=1.58e-9) for ΔTHR; this gene locus has been reported before influencing baseline THR levels. Our GWLS found evidence for a significant linkage with a logarithm of the odds (LODs) exceeding 3 on 3q28 (LODs=4.1). Using a subset of 25 linkage enriched families (pedigree-specific LODs>0.1), we assessed sequence elements under 3q28 and identified two novel variants (EIF4A2/ADIPOQ-rs114108468, p=5e-6, MAF=1.8%; TPRG1-rs16864075, p=3e-6, MAF=8%; accounted for ~28% and ~29% of the linkage, respectively, and 57% jointly). While the former variant was associated with EIF4A2 (p=7e-5) / ADIPOQ (p=3.49e-2) RNA transcriptional levels, the latter variant was not associated with TPRG1 (p=0.23) RNA transcriptional levels. Replication in FHS OS observed modest effect of these loci on ΔTHR. Of 188 metabolites from 13 compound classes assayed in LLFS, we observed multiple metabolites (e.g., DG.38.5, PE.36.4, TG.58.3) that were significantly associated with the variants (p<3e-4).

Conclusions

our linkage-guided sequence analysis approach permitted our discovery of two novel gene variants EIF4A2/ADIPOQ-rs114108468 and TPRG1-rs16864075 on 3q28 for ΔTHR among subjects without diabetes selected for exceptional survival and healthy aging.

Dietary intervention with 2 different fat profiles; role of the rs822393 variant in metabolic parameter changes

Introduction

Introduction: rs822393 is related to dietary intervention responses. The aim of our study was to analyze the metabolic effects of 2 hypocaloric diets with a different fat profile during 3 months according to the genetic variant rs822393. Methods: a population of 361 obese patients were randomly allocated to one of two diets; Diet P (enriched in polyunsaturated fatty acids) vs. Diet M (enriched in monounsaturated fatty acids). Adiposity and biochemical parameters were determined. rs822393 was assessed by real-time PCR, with a dominant model analysis (CC vs CT+TT). Results: genotype distribution was: 221 CC (61.2 %), 115 CT (31.9 %) and 25 TT (6.9 %). Basal and post-intervention HDL cholesterol, adiponectin levels and adiponectin/leptin ratio were lower in T-allele than non-T-allele carriers. After both diets, BMI, weight, fat mass, waist circumference, systolic blood pressure, insulin levels, HOMA-IR, leptin, total cholesterol and LDL-cholesterol improved significantly in both genotype groups. After Diet P, HDL-cholesterol (delta: 5.6 ± 1.1 mg/dl vs. 2.7 ± 0.9 mg/dl; p = 0.01), serum adiponectin (20.1 ± 2.9 ng/dl vs. 6.8 ± 3.0 ng/dl; p = 0.02) and adiponectin/leptin ratio (0.57 ± 0.1 units vs. 0.20 ± 0.08 units; p = 0.03) improved in non-T allele carriers. The same improvements were observed after Diet M: HDL-cholesterol (delta: 5.5 ± 0.8 mg/dl vs. 3.1 ± 0.9 mg/dl; p = 0.03), serum adiponectin (19.5 ± 2.9 ng/dl vs. 4.5 ± 2.8 ng/dl; p = 0.01), and adiponectin/leptin ratio (0.54 ± 0.1 units vs. 0.15 ± 0.08 units; p = 0.03). These parameters remained unchanged in T-allele carriers. Conclusion: after two different hypocaloric diets, obese subjects with the T allele of rs822393 did not improve their adiponectin levels, ratio adiponectin/leptin, and HDL-cholesterol, despite loss of weight.

A 67-bp variable duplication in the promoter region of the ADIPOQ is associated with milk traits in Xinjiang brown cattle

Adiponectin, also known as ADIPOQ, is a hormone protein secreted by adipocytes. The ADIPOQ gene is expressed primarily in adipose tissue, and the encoded protein circulates in the bloodstream and has the potential to regulate both animal fat metabolism and hormone production. Our previous work uncovered a 67-bp variable duplication in the promoter region of ADIPOQ, which reduced the basal transcriptional activity of ADIPOQ in the 3T3_L1 cell and also inhibits the ADIPOQ mRNA expression in adipose tissue. Accordingly, the present study aimed to identify the relationship between the 67-bp structural variations in ADIPOQ promoter region and the milk traits of Xinjiang brown cattle (XJBC). The results revealed two genotypes, DD and ID, in the XJBC, and minor allelic frequency (MAF) for the 'I' allele was more than 1%. Moreover, the association analysis revealed that the 67-bp duplication in the promoter region of the ADIPOQ gene was significantly correlated with the 305 days of milk production volume, fat yield, and milk fat percentage in the XJBC (p < 0.05). These results obtained in this study suggested that the identified variable duplication could be considered as the potential genetic marker for improving milk traits of XJBC.

Dietary Intervention during 9 Months with a Hypocaloric Diet, Interaction of the Genetic Variant of Adiponectin Gene rs822393 with Metabolic Parameters

Background and Aims

rs822393 (-4522C/T) genetic variant is associated with hypoadiponectinemia and other metabolic parameters. The aim of our investigation was to analyze the effects of a hypocaloric diet with Mediterranean dietary pattern during 9 months according to genetic variant rs822393 of ADIPOQ gene.

Methods and Results

A sample of 269 obese patients was enrolled. Anthropometric and serum parameters (lipid profile, insulin, homeostasis model assessment (HOMA-IR), glucose, C reactive protein, and adipokines) were determined, at basal time and after 3 and 9 months. All patients were genotyped in the rs822393. The genotype distribution was as follow; 176 patients (65.4%) CC, 83 patients CT (30.9%), and 10 patients TT (3.7%). After dietary intervention, the following parameters improved in non-T allele carriers; BMI, weight, fat mass, waist circumference, systolic blood pressure, insulin levels, HOMA-IR, leptin, total cholesterol, and LDL-cholesterol improved significantly. HDL-cholesterol (delta: 5.7 ± 1.1 mg/dl vs. 1.0 ± 0.8 mg/dl; p = 0.01), serum adiponectin (delta: 14.4 ± 2.0 ng/dl vs. 7.1 ± 3.1 ng/dl; p = 0.02), and adiponectin/leptin ratio (delta: 0.54 ± 0.1 vs. 0.22 ± 0.09 ng/dl; p = 0.03). Basal and postintervention HDL cholesterol, adiponectin levels, and adiponectin/leptin levels were lower in T-allele carriers than non-T Allele carriers.

Conclusion

T allele carriers showed lower levels of HDL-cholesterol, adiponectin, and adiponectin/leptin ratio than non-T allele carriers. A medium-term hypocaloric diet with a Mediterranean partner increased adiponectin levels, ratio adiponectin/leptin, and HDL-cholesterol in non-T allele carriers.

Association of ADIPOQ Single-Nucleotide Polymorphisms with the Two Clinical Phenotypes Type 2 Diabetes Mellitus and Metabolic Syndrome in a Kinh Vietnamese Population

PURPOSE

Genetic factors play an important role in the development of type 2 diabetes mellitus (T2DM) and metabolic syndrome (MetS). However, few genetic association studies related to these disorders have been performed with Vietnamese subjects. In this study, the potential associations of ADIPOQ single nucleotide polymorphisms (SNPs) with T2DM and MetS in a Kinh Vietnamese population were investigated.

PATIENTS AND METHODS

A study with 768 subjects was conducted to examine the associations of four ADIPOQ SNPs (rs266729, rs1501299, rs3774261, and rs822393) primarily with T2DM and secondarily with MetS. The TaqMan SNP genotyping assay was used to determine genotypes from subjects' DNA samples.

RESULTS

After statistical adjustment for age, sex, and body mass index, the ADIPOQ SNP rs266729 was found to be associated with increased risk of T2DM under multiple inheritance models: codominant (OR = 2.30, 95% CI = 1.16-4.58), recessive (OR = 2.17, 95% CI = 1.11-4.26), and log-additive (OR = 1.32, 95% CI = 1.02-1.70). However, rs1501299, rs3774261, and rs822393 were not associated with risk for T2DM. Additionally, rs266729, rs3774261, and rs822393 were statistically associated with MetS, while rs1501299 was not. Haplotype analysis showed a strong linkage disequilibrium between the SNP pairs rs266729/rs822393 and rs1501299/rs3774261, and the haplotype rs266729(G)/rs822393(T) was not statistically associated with MetS.

CONCLUSION

The results show that rs266729 is a lead candidate SNP associated with increased risk of developing T2DM and MetS in a Kinh Vietnamese population, while rs3774261 is associated with MetS only. Further functional characterization is needed to uncover the mechanism underlying the potential genotype-phenotype associations.

Adiponectin gene polymorphisms associated with diabetes mellitus: A descriptive review

Diabetes is currently a growing concern of the age. Prevention and treatment of diabetes is a global health priority. Adiponectin is an adipocyte derived protein hormone that enhances insulin sensitivity and ameliorates diabetes by enhancing fatty acid oxidation and glucose uptake in skeletal muscle and reducing glucose production in the liver. Low serum adiponectin concentrations are associated with diabetes, central obesity, insulin resistance and metabolic syndrome. Adiponectin gene is located on chromosome 3q27, where a locus of susceptibility to diabetes was mapped. Several cross-sectional studies showed that single nucleotide polymorphisms (SNPs) in adiponectin gene (ADIPOQ) were associated with diabetes. SNPs in ADIPOQ help in assessing the association of common variants with levels of adiponectin and the risk of diabetes. Two common SNPs, rs2241766 and rs1501299, have been linked significantly to type 1 diabetes mellitus which endow the world with a block of haplotypes. Experimental evidences also suggest that rs1501299, rs2241766, rs266729, rs17366743, rs17300539, rs182052, rs822396, rs17846866, rs3774261 and rs822393 are significantly associated with type 2 diabetes mellitus which is the predominant form of the disease. In addition, rs2241766 and rs266729 are extensively associated with gestational diabetes, a condition that develops in women during pregnancy. Therefore not a particular single mutation but a number of SNPs in adiponectin gene could be a risk factor for developing diabetes among the individuals worldwide. This study firmly suggests that adiponectin plays a crucial role in the pathogenesis of type 1, type 2 and gestational diabetes mellitus.

Adiponectin gene variant rs266729 interacts with different macronutrient distributions of two different hypocaloric diets during nine months

Introduction

Background: the role of ADIPOQ gene variants on metabolic changes after weight loss secondary to different hypocaloric diets remains unclear and poorly investigated. Objective: we evaluated the effect of polymorphism rs266729 of ADIPOQ gene on biochemical changes and weight loss after a high-protein/low-carbohydrate diet vs a standard severe hypocaloric diet during 9 months. Material and methods: a population of 269 obese patients was enrolled in a randomized intervention trial for 9 months with two diets. Diet HP (high protein) was 33 % of carbohydrates (86.1 g/day), 33 % of fat (39.0 g/day), and 34 % of proteins (88.6 g/day). Diet S (standard) was 1093 cal/day, 53 % carbohydrates (144.3 g/day), 27 % fats (32.6 g), and 20 % proteins (55.6 g/day). Before and after the intervention an anthropometric evaluation, an assessment of nutritional intake, and a biochemical analysis were carried out. Results: all patients lost weight regardless of genotype and diet. After the intervention with a high protein hypocaloric diet (diet HP) only subjects with CC genotype showed significant improvement in cholesterol (14.4 ± 1.8 md/dL vs -5.0 ± 1.9 mg/dL; p = 0.02), LDL-cholesterol (14.4 ± 1.9 mg/dL vs -5.1 ± 1.8 mg/dL; p = 0.01), insulin (-4.1 ± 0.3 mU/L vs -2.0 ± 0.6 mU/L; p = 0.02), HOMA-IR (-1.4 ± 0.2 units vs -0.5 ± 0.3 units; p = 0.02) and adiponectin (10.2 ± 1.4 ng/dL vs 3.1 ± 1.1 ng/dL; p = 0.01) levels. After the second dietary strategy with a standard hypocaloric diet (diet S) only subjects with CC genotype showed significant improvement in total cholesterol (CC vs CG + GG) (-17.1 ± 1.9 md/dL vs -5.3 ± 1.3 mg/dL; p = 0.02), LDL-cholesterol (-12.3 ± 1.9 mg/dL vs -8.0 ± 1.2 mg/dL; p = 0.01), insulin (-4.0 ± 0.9 mU/L vs -1.3 ± 0.5 mU/L; p = 0.02), HOMA-IR (-1.2 ± 0.1 units vs -0.6 ± 0.2 units; p = 0.02), and adiponectin (11.1 ± 2.7 ng/dL vs 3.3 ± 1.2 ng/dL; p = 0.02) levels. Conclusion: non G-allele carriers showed a better response of LDL-cholesterol, HOMA-IR, insulin, and adiponectin levels than G-allele carriers before weight loss with both diets.

Adiponectin receptor 1 gene is potentially associated with severity of postoperative pain but not cancer pain

Adiponectin is an adipose tissue-derived cytokine that exerts its antiinflammatory effects by binding to 2 adiponectin receptors, adiponectin receptor 1 (ADIPOR1) and adiponectin receptor 2 (ADIPOR2). However, the role of these adiponectin receptors on inflammatory pain remains unclear. We investigated the association between single nucleotide polymorphisms (SNPs) of these genes and inflammatory pain, such as postoperative pain and cancer pain.We analyzed 17 SNPs of the ADIPOR1 gene and 27 SNPs of the ADIPOR2 gene in 56 adult patients with postlaparotomy pain. We compared these genotypes with pain intensity and opioid consumption, adjusting for multiple testing. We analyzed the genotypes of 88 patients with cancer pain and examined the association of the relevant SNP(s) with pain intensity and opioid consumption.One variant of the ADIPOR1 gene (rs12045862) showed significant association with postoperative pain intensity; patients with minor allele homozygote (n = 7) demonstrated significantly worse pain intensity than that of combined patient group exhibiting major allele homozygote or the heterozygote (n = 49; Mann-Whitney test, P < .00002), although their opioid consumptions were comparable. Cancer pain intensity between minor allele homozygote patients (n = 7) and other 2 genotype patients (n = 81) were comparable.The rs12045862 SNP of the ADIPOR1 gene was associated with postoperative pain but not cancer pain. This might result from functional alteration of the ADIPOR1 signalling pathways, which influence the inflammatory process. ADIPOR1 may be a novel potential target for developing analgesics of postoperative pain.

Effect of two different dietary fatty acid profiles and variant rs266729 in ADIPOQ on weight loss and adiponectin concentrations

BACKGROUND

The role of ADIPOQ gene rs266729 variants on weight loss after a dietary intervention are still unclear.

OBJECTIVE

To analyze the effects of the ADIPOQ gene rs266729 variant n weight loss, cardiovascular risk factors, and adiponectin levels after two hypocaloric diets with different dietary fatty profiles.

DESIGN

A population of 362 obese patients was enrolled in a randomized clinical trial with two diets (Diet M, monounsaturated fat-enriched diet, and Diet P, polyunsaturated-fat enriched diet). Anthropometric measurements, an assessment of nutritional intake, and biochemical tests were performed at baseline and after 12 weeks.

RESULTS

Weight loss was similar with both diets. After Diet M, only subjects with CC genotype showed significant improvements in total cholesterol (CC vs. CG±GG) (-9.0±1.1mU/L vs. -4.5±2.4mg/dL, p=0.01), LDL cholesterol (-6.0±1.1mg/dL vs. -3.0±0.9mg/dL, p=0.03), glucose (-4.7±1.1mg/dL vs. -0.6±0.5mg/dL, p=0.01), and insulin levels (-2.6±1.0mU/L vs. -0.7±0.3mU/L, p=0.02) and in HOMA-IR (-0.5±0.2 units vs. -0.2±0.4 units, p=0.03). The same improvement was reported after Diet P in all parameters, including total cholesterol (CC vs. CG±GG) (-8.0±1.2mU/L vs. -2.1±1.4mg/dL, p=0.02), LDL cholesterol (-7.3±1.2mg/dL vs. -2.1±0.8mg/dL, p=0.02), glucose (-3.2±0.1mg/dL vs. -0.2±0.5mg/dL, p=0.01), and insulin levels (-2.5±1.0mU/L vs. -1±0.6mU/L, p=0.02) and HOMA-IR (-0.5±0.1 units vs. -0.3±0.4 units, p=0.02). Only subjects with CC genotype showed significant increases in adiponectin levels after both diets: (Diet M: 10.3±2.0ng/dL vs. Diet P: 9.3±2.9ng/dL, p=0.43).

CONCLUSION

The CC genotype of ADIPOQ gene rs266729 variant is associated to increased adiponectin levels and decreases in LDL cholesterol, glucose, insulin, and HOMA-IR levels after weight loss.

Adiponectin Gene Variant rs266729 Interacts with Different Macronutrient Distribution of Two Different Hypocaloric Diets

BACKGROUND

The role of ADIPOQ gene variants in weight loss after different dietary fat amounts remains unclear.

OBJECTIVE

Our aim was to analyze the effects of ADIPOQ gene polymorphism rs266729 on metabolic changes after two different amounts of dietary fat in two hypocaloric diets.

DESIGN

A population of 283 obese patients was recruited in a randomized clinical trial with two diets: Diet HF (high-fat diet: 38% carbohydrates, 24% proteins, and 38% fats) versus Diet LF (low-fat diet: 53% carbohydrates, 20% proteins, and 27% fats). Before and after 3 months, an anthropometric evaluation, an assessment of nutritional intake, and a biochemical analysis were carried out. The variant of the ADIPOQgene was assessed by real-time PCR.

RESULTS

Weight loss was similar with both diets in both genotypes (CC vs. CG+GG). After dietary intervention with Diet HF, only subjects with CC genotype showed a significant improvement in insulin levels (-3.3 ± 0.6 vs. -1.8 ± 0.9 mU/L; p = 0.03) and the homeostasis model assessment for insulin resistance (HOMA-IR) (-1.3 ± 0.1 vs. -0.8 ± 0.2 units; p = 0.02). After Diet LF, subjects with CC genotype showed a significant improvement in total cholesterol levels (CC vs. CG+GG) (-15.3 ± 1.4 vs. -6.4 ± 1.3 mg/dL; p = 0.01), LDL cholesterol (-14.6 ± 1.8 vs. -6.4 ± 1.3 mg/dL; p = 0.01), insulin levels (-4.6 ± 1.0 vs. -1.6 ± 0.5 mU/L; p = 0.01), and HOMA-IR (-1.6 ± 0.1 vs. -1.0 ± 0.2 units; p = 0.02). Only subjects with CC genotype showed a significant increase of adiponectin levels after both diets (CC vs. CG+GG): Diet HF (10.6 ± 2.0 vs. 1.8 ± 1.0 ng/dL; p = 0.01) and Diet LF (16.1 ± 2.8 vs. 1.3 ± 1.0 ng/dL: p = 0.03).

CONCLUSION

CC genotype of ADIPOQgene variantrs266729 was associated with a better metabolic response after both diets. Additionally, Diet LF produced a significant improvement in lipid profile in noncarriers of allele G.

Adiponectin gene variant RS rs266729: Relation to lipid profile changes and circulating adiponectin after bariatric surgery

BACKGROUND

ADIPOQ rs266729 have been associated with body mass index and metabolic parameters.

OBJECTIVES

Our aim was to assess the contribution of this genetic variant on lipid profile and serum adiponectin levels after biliopancreatic diversion surgery in morbidly obese patients in a 3-year prospective study.

SETTING

Tertiary Hospital.

METHODS

A prospective cohort study (sample) of 149 patients with morbid obesity was evaluated. Biochemical and anthropometric parameters were studied at baseline and every year for a 3-year-follow-up period.

RESULTS

Percentage of excess weight loss (65.9% versus 66.0%:ns), body mass index, weight, waist circumference, fat mass, blood pressure, fasting glucose, low-density lipoprotein cholesterol, total cholesterol, insulin, homeostasis model assessment of insulin resistance, and triglyceride levels improved in both genotype groups. A decrease in fasting insulin levels, homeostasis model assessment of insulin resistance, total cholesterol, low-density lipoprotein cholesterol, and triglycerides was higher in non-G-allele carriers than G-allele carriers. The increase of adiponectin levels (at 1 yr) found after 1 (delta: 16.2 ± 3.1 ng/mL versus 2.1 ± 1.0 ng/mL; P = .02), 2 (delta: 24.2 ± 3.1 ng/mL versus 3.1 ± 1.1 ng/mL; P = .02), and 3 years (delta: 33.2 ± 3.9 ng/mL versus 4.7 ± 1.8 ng/mL; P = .01) was higher in non-G-allele carriers than G carriers. At all times, adiponectin levels were higher in patients with genotype CC.

CONCLUSIONS

Non-G allele of ADIPOQ gene variant (rs266729) is associated with increases in adiponectin levels and better improvement of low-density lipoprotein cholesterol, triglycerides, insulin, and homeostasis model assessment of insulin resistance after biliopancreatic diversion massive weight loss than G-allele carriers.

Variations in ADIPOR1 But Not ADIPOR2 are Associated With Hypertriglyceridemia and Diabetes in an Admixed Latin American Population

BACKGROUND

Adiponectin is a hormone secreted by adipose tissue. It regulates glycolysis and lipolysis and is involved in the pathophysiology of diabetes and related disorders. Its activity is mainly mediated by the transmembrane receptors AdipoR1 and AdipoR2, which are encoded by ADIPOR1 (1q32.1) and ADIPOR2 (12p13.33) genes, respectively. In genetic association studies, single nucleotide polymorphisms (SNPs) in or near these genes have been associated with metabolic alterations. However, these relationships are still controversial.

AIM

The aim of this work was to analyze possible associations between ADIPOR1/2 and diabetes and other metabolic disorders.

METHODS

A genetic association study was carried out in an admixed Latin American population. A sample of 200 adults was analyzed. Clinical and serum-biochemical characteristics were measured to diagnose obesity, abdominal obesity, hypertension, hyperglycemia, hypertriglyceridemia, low HDLc, insulin resistance (HOMA-IR), and diabetes. Three SNPs were genotyped in ADIPOR1 (rs10494839, rs12733285, and rs2275737) and ADIPOR2 (rs11061937, rs11612383, and rs2286383). For the association analysis, an additive model was assessed through logistic regression. An admixture adjustment was performed using a Monte-Carlo-Markov-Chain method, assuming a three-hybrid substructure (k = 3).

RESULTS

Two SNPs in ADIPOR1 were associated with diabetes: rs10494839 (OR = 3.88, adjusted p < 0.03) and rs12733285 (OR = 4.72, adjusted p < 0.03). Additionally, rs10494839 was associated with hypertriglyceridemia (OR = 2.16, adjusted p < 0.01). None of the SNPs in ADIPOR2 were associated with metabolic disorders.

CONCLUSIONS

ADIPOR1 was consistently associated with diabetes and hypertriglyceridemia. This association was maintained even after adjusting for genetic stratification. There were no significant associations involving ADIPOR2.

Baseline metabolic disturbances and the twenty-five years risk of incident cancer in a Mediterranean population

BACKGROUND AND AIMS

Obesity is predictive of metabolic syndrome (metS), type 2 diabetes, cardiovascular (CV) disease and cancer. The aim of the study is to assess the risk of incident cancer connected to obesity and metS in a Mediterranean population characterized by a high prevalence of obesity.

METHODS AND RESULTS

As many as 1133 subjects were enrolled in two phases and followed for 25 years (859 subjects) or 11 years (274 subjects) and incident cancer was registered in the follow-up period. Anthropometric measures and biochemical parameters were filed at baseline and evaluated as predictors of incident cancer by measuring hazards ratios (HR) using multivariate Cox parametric hazards models. Best predictive threshold for metabolic parameters and metS criteria were recalculated by ROC analysis. Fasting Blood Glucose >5.19 mmol/L [HR = 1.58 (1.0-2.4)] and the TG/HDL ratio (log₁₀) (Males > 0.225, Females > 0.272) [HR = 2.44 (1.3-4.4)] resulted independent predictors of survival free of cancer with a clear additive effect together with age classes [45-65 years, HR = 2.47 (1.3-4.4), 65-75 years HR = 3.80 (2.0-7.1)] and male gender [HR = 2.07 (2.3-3.1)].

CONCLUSIONS

Metabolic disturbances are predictive of cancer in a 25 years follow-up of a Mediterranean population following a traditional Mediterranean diet. The high prevalence of obesity and metS and the observed underlying condition of insulin resistance expose this population to an increased risk of cardiovascular disease and cancer despite the healthy nutritional habits.

A Variant in ADIPOR2 Is Associated with Increased Free Fatty Acid Levels in Chinese Population

BACKGROUND

Elevated free fatty acids (FFAs) are thought to play an important role in the development of insulin resistance. Adiponectin is an adipose tissue-secreted protein known for its effects on the stimulation of fatty acid oxidation. The aim of this study was to investigate the association of adiponectin receptor 2 gene variations with FFAs levels in subjects with normal fasting glucose levels in Chinese Han population.

METHODS

Four common single nucleotide polymorphisms of ADIPOR2 were genotyped using the TaqMan method to perform association studies with metabolic parameters in 1819 subjects among Chinese Han population. All the subjects were divided into two groups: normal FFAs group (FFAs ≤0.88 mmol/L) and high FFAs group (FFAs >0.88 mmol/L).

RESULTS

There was a significant association of rs2370055 with higher FFA levels in major T-allele carriers (P = 0.000). There was a significant difference in the distribution of genotypes of polymorphism rs2370055 between normal and high FFA groups. The frequencies of TT and CT genotypes are significantly higher in subjects with high FFA level than those in the normal FFAs group (P = 0.013 and P = 0.004, respectively). After adjustment for age, sex, body mass index, triglyceride, total cholesterol, high-density lipoprotein cholesterol, and low-density lipoproteincholesterol, the TT and CT genotypes are both independent risk factors for high FFAs level.

CONCLUSIONS

Our findings suggest that variants of ADIPOR2 could be a determinant for higher FFA levels, and among Chinese Han population, carriers of the CT and TT genotypes for rs2370055 even with normal glucose levels may have significantly higher insulin resistance susceptibility.

Association of adiponectin gene polymorphisms and additional gene-gene interaction with nonalcoholic fatty liver disease in the Chinese Han population

PURPOSE

To investigate the association between the single nucleotide polymorphisms (SNPs) of the adiponectin gene and nonalcoholic fatty liver disease (NAFLD) as well as the impact of the interaction of multiple SNPs on NAFLD risk, based on a Chinese population study.

METHODS

A total of 612 subjects (411 male, 201 female) were selected, including 302 NAFLD patients and 310 controls. Three SNPs were selected for genotyping in the case-control study: rs266729, rs822393, and rs1501299. A logistic regression model was used to examine the interaction between the SNPs and NAFLD. The odds ratio (OR) and 95 % confidence interval (95 % CI) were calculated. Generalized multifactor dimensionality reduction (GMDR) was employed to analyze the interaction among SNPs.

RESULTS

Logistic analysis showed a significant association between genotypes of variants in rs266729 and rs822393 and increased NAFLD risk. The carriers of the homozygous mutant of two SNP polymorphisms revealed increased NAFLD risk compared to those with wild-type homozygotes; ORs (95 % CI) were 1.31 (1.14-1.81) (p = 0.001) and 1.18 (1.05-1.71) (p = 0.005), respectively. There was a significant two-locus model (p = 0.0010) involving rs266729 and rs822393, indicating a potential gene-gene interaction between rs266729 and rs822393. Overall, the two-locus models had a cross-validation consistency of 10 and testing accuracy of 62.17 %. Subjects with the CG or GG and CT or TT genotype have the highest NAFLD risk compared to subjects with the CC-CC genotype; the OR (95 % CI) was 2.52 (1.31-3.82), p < 0.001, after covariate adjustment.

CONCLUSIONS

Our results support an important association of the rs266729 (-11377 G/C) and rs822393 (-4522 C/T) polymorphism with increased risk of NAFLD. The interaction analysis showed a combined effect of rs266729 and rs822393 on NAFLD.

Genetic association of ADIPOQ gene variants with type 2 diabetes, obesity and serum adiponectin levels in south Indian population

OBJECTIVE

To investigate the genetic association of eight variants of the adiponectin gene with type 2 diabetes mellitus (T2DM), obesity and serum adiponectin level in the south Indian population.

METHODS

The study comprised of 1100 normal glucose tolerant (NGT) and 1100 type 2 diabetic, unrelated subjects randomly selected from the Chennai Urban Rural Epidemiology Study (CURES), in southern India. Fasting serum adiponectin levels were measured by radioimmunoassay. The variants were screened by polymerase chain reaction-restriction fragment length polymorphism. Linkage disequilibrium was estimated from the estimates of haplotype frequencies.

RESULTS

Of the 8 variants, four SNPs namely, +276 G/T (rs1501299), -4522 C/T (rs822393), -11365 C/G (rs266729), and +712 G/A (rs3774261) were significantly associated with T2DM in our study population. The -3971 A/G (rs822396) and -11391 G/A (rs17300539) SNPs' association with T2DM diabetes was mediated through obesity (where the association with type 2 diabetes was lost after adjusting for BMI). There was an independent association of +276 G/T (rs1501299) and -3971 A/G (rs822396) SNPs with generalized obesity and +349 A/G (rs2241767) with central obesity. Four SNPs, -3971 A/G (rs822396), +276 G/T (rs1501299), -4522 C/T (rs822393) and Y111H T/C (rs17366743) were significantly associated with hypoadiponectinemia. The haplotypes GCCATGAAT and AGCGTGGGT conferred lower risk of T2DM in this south Indian population.

CONCLUSION

The adiponectin gene variants and haplotype contribute to the genetic risk towards the development of type 2 diabetes, obesity and hypoadiponectinemia in the south Indian population.

Genetic variants in the ADIPOQ gene and the risk of metabolic syndrome: a case-control study of a Chinese Han population

Our aim was to investigate whether the ADIPOQ gene polymorphisms are associated with the metabolic syndrome (MetS). Genotypes of MetS patients (n=1049) and normal controls (n= 1092) were analysed by TaqMan® assay, and serum adiponectin concentration was measured by ELISA. The variant genotypes rs266729CG; rs1063539GC, GC/CC; rs16861205AA and rs7649121AT, AT/TT (Adjusted P=0.037, 0.044, 0.025, 0.011, 0.019, 0.020, respectively) of the ADIPOQ gene were associated with MetS. Patients with rs266729CG, CG/GG genotypes (P=0.034, 0.035) and rs7649121AT, AT/TT genotypes (P=0.013, 0.022) had higher levels of serum adiponectin than those with the CC and AA genotypes respectively. Furthermore, the prevalence of haplotypes GGAAAATC and GGGTAACC was lower in cases (10.7% and 4.5%) than in controls (12.1% and 5.9%) [Adjusted ORs (95% CIs)=0.70 (0.54–0.91), 0.65 (0.46–0.92)]. The ADIPOQ gene variants associated with the risk of MetS in this study must be validated by further functional studies to reveal any potential effects on metabolism.

The use of race, ethnicity and ancestry in human genetic research

Post-Human Genome Project progress has enabled a new wave of population genetic research, and intensified controversy over the use of race/ethnicity in this work. At the same time, the development of methods for inferring genetic ancestry offers more empirical means of assigning group labels. Here, we provide a systematic analysis of the use of race/ethnicity and ancestry in current genetic research. We base our analysis on key published recommendations for the use and reporting of race/ethnicity which advise that researchers: explain why the terms/categories were used and how they were measured, carefully define them, and apply them consistently. We studied 170 population genetic research articles from high impact journals, published 2008-2009. A comparative perspective was obtained by aligning study metrics with similar research from articles published 2001-2004. Our analysis indicates a marked improvement in compliance with some of the recommendations/guidelines for the use of race/ethnicity over time, while showing that important shortfalls still remain: no article using 'race', 'ethnicity' or 'ancestry' defined or discussed the meaning of these concepts in context; a third of articles still do not provide a rationale for their use, with those using 'ancestry' being the least likely to do so. Further, no article discussed potential socio-ethical implications of the reported research. As such, there remains a clear imperative for highlighting the importance of consistent and comprehensive reporting on human populations to the genetics/genomics community globally, to generate explicit guidelines for the uses of ancestry and genetic ancestry, and importantly, to ensure that guidelines are followed.

Adiponectin gene polymorphisms (T45G and G276T), adiponectin levels and risk for metabolic diseases in an Arab population

In this study we examined the association of adiponectin gene variants with circulating adiponectin, and known metabolic diseases in 298 healthy controls and 297 Saudi subjects with type 2 diabetes mellitus (T2DM). Anthropometric and biochemical parameters were measured by standard procedures. Genotyping of T45G and G276T single nucleotide polymorphisms of adiponectin gene was carried out by PCR-RFLP analysis. No significant differences in the genotype distribution of T45G and G276T polymorphism were found between control and diabetic subjects. Neither SNP conferred an association with T2DM, obesity, hypertension or dyslipidemia. Despite a marked decrease in patients as opposed to controls, adiponectin levels were not different according to genotypes of T45G and G276T polymorphisms in control and patients. Thus, neither adiponectin SNPs independently conferred increased T2DM risk nor in other metabolic conditions considered such as obesity, hypertension or dyslipidemia. These findings support the existence of population based differences in the association of adiponectin gene variants with metabolic phenotypes and emphasize the importance of studying multiple polymorphisms, sufficient enough to identify the adiponectin gene as a genetic marker for several non-chronic communicable diseases.

Genetic polymorphisms in obesity-related genes and endometrial cancer risk

BACKGROUND

Obesity is associated with circulating levels of adiponectin and leptin and endometrial cancer risk. Little is known about whether single nucleotide polymorphisms (SNPs) in the genes that encode adiponectin (ADIPOQ), leptin (LEP), adiponectin receptor 1 (ADIPOR1), adiponectin receptor 2 (ADIPOR2), and leptin receptor (LEPR) are associated with endometrial cancer.

METHODS

The authors selected 87 tagging SNPs to capture common genetic variants in these 5 genes. These SNPs were evaluated in 1028 endometrial cancer cases and 1932 community controls recruited from Chinese women. Logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs).

RESULTS

Three of the 10 SNPs evaluated in the ADIPOQ gene were significantly associated with reduced cancer risk. The OR for women homozygous for the minor allele (A/A) for rs3774262 was 0.68 (95% CI, 0.48-0.97) compared with women homozygous for the major allele (G/G). Similar results were found for SNPs rs1063539 and rs12629945 in ADIPOQ, which were in linkage disequilibrium with rs3774262. These associations became nonsignificant after Bonferroni correction was applied. Controls with the minor allele A at rs3774262 had lower weight, smaller waist and hip circumferences, and lower body mass index than controls with the major allele G (all P < .05). Women homozygous for the minor allele (T/T) of rs2071045 in the LEP gene also had significantly lower risk (OR, 0.70; 95% CI, 0.54-0.90) than women homozygous for the major allele (C/C). No other SNPs in the LEP, ADIPOR1, ADIPOR2, or LEPR genes were found to be associated with cancer risk.

CONCLUSIONS

Although a chance finding cannot be ruled out, the consistency of findings for gene-endometrial cancer risk and gene-obesity measurements suggests that genetic polymorphisms in the ADIPOQ gene may play a role in endometrial cancer development.

Association of ADIPOR2 gene variants with cardiovascular disease and type 2 diabetes risk in individuals with impaired glucose tolerance: the Finnish Diabetes Prevention Study

BACKGROUND

Adiponectin is an adipokine with insulin-sensitising and anti-atherogenic effects. Two receptors for adiponectin, ADIPOR1 and ADIPOR2, have been characterized that mediate effects of adiponectin in various tissues. We examined whether genetic variation in ADIPOR2 predicts the development of cardiovascular disease (CVD) and/or Type 2 Diabetes (T2DM) in individuals with impaired glucose tolerance (IGT) participating the Finnish Diabetes Prevention Study (DPS).

METHODS

CVD morbidity and mortality data were collected during a median follow-up of 10.2 years (range 1-13 years) and conversion from IGT to T2DM was assessed during a median follow-up of 7 years (range 1-11 years). Altogether eight SNPs in the ADIPOR2 locus were genotyped in 484 participants of the DPS. Moreover, the same SNPs were genotyped and the mRNA expression levels of ADIPOR2 were determined in peripheral blood mononuclear cells and subcutaneous adipose tissue samples derived from 56 individuals participating in the Genobin study.

RESULTS

In the DPS population, four SNPs (rs10848554, rs11061937, rs1058322, rs16928751) were associated with CVD risk, and two remained significant (p = 0.014 for rs11061937 and p = 0.020 for rs1058322) when all four were included in the same multi-SNP model. Furthermore, the individuals homozygous for the rare minor alleles of rs11061946 and rs11061973 had increased risk of converting from IGT to T2DM. Allele-specific differences in the mRNA expression levels for the rs1058322 variant were seen in peripheral blood mononuclear cells derived from participants of the Genobin study.

CONCLUSIONS

Our results suggest that SNPs in the ADIPOR2 may modify the risk of CVD in individuals with IGT, possibly through alterations in the mRNA expression levels. In addition an independent genetic signal in ADIPOR2 locus may have an impact on the risk of developing T2DM in individuals with IGT.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov NCT00518167.

Influence of the interaction between the adiponectin G276T polymorphism and body mass index on lipid levels in healthy children

Adiponectin is an adipose tissue-specific hormone which is inversely associated with metabolic alterations related to atherosclerosis. Polymorphisms in the adiponectin gene (AdipoQ) have been related to low adiponectin levels as well as several cardiovascular risk factors, but this association remains controversial. In our study we investigated the relationship between the AdipoQ T45G (rs: 2241766) and G276T (rs: 1501299) polymorphisms and adiponectin concentrations, blood pressure, and lipid and insulin levels, in a population-based sample of 12- to 16-year-old children. The study included 815 healthy Spanish children (388 boys and 427 girls). Plasma glucose and lipid levels were determined by standard methods. Insulin concentrations were measured by RIA, and serum adiponectin levels were determined by ELISA. The AdipoQ T45G and AdipoQ G276T polymorphisms were determined by TaqMan(®) allelic discrimination assays. ANOVA or t test allowed for comparison of the studied parameters across genotypes or genotype groups, respectively. A linear regression analysis was performed to examine the independent relationships of the lipid variables with BMI (body mass index), AdipoQ G276T polymorphism and the interaction between the two. When independently comparing the effect of these polymorphisms in normal-weight and overweight children, we observed that overweight boys carriers of the minor allele T had significantly lower TC, LDL-C and apo A-I levels than non-carriers, but these differences were not apparent in normal-weight boys. Furthermore, linear regression analysis demonstrated that interaction between the BMI and the AdipoQ G276T polymorphism is a significant factor explaining the variations of TC and LDL-C levels. To our knowledge, this is the first study to report an association between the AdipoQ G276T polymorphism and lipid levels in overweight boys alone, thereby suggesting that the influence of the AdipoQ polymorphisms on cardiovascular risk factors may be dependent on BMI.

Body mass index and obesity- and diabetes-associated genotypes and risk for pancreatic cancer

BACKGROUND

The genetic factors predisposing individuals with obesity or diabetes to pancreatic cancer have not been identified.

AIMS

To investigate the hypothesis that obesity- and diabetes-related genes modify the risk of pancreatic cancer.

METHODS

We genotyped 15 single nucleotide polymorphisms of fat mass and obesity-associated (FTO), peroxisome proliferators-activated receptor gamma (PPARγ), nuclear receptor family 5 member 2 (NR5A2), AMPK, and ADIPOQ genes in 1,070 patients with pancreatic cancer and 1,175 cancer-free controls. Information on risk factors was collected by personal interview. Adjusted ORs (AOR) and 95% CIs were calculated using unconditional logistic regression.

RESULTS

The PPARγ P12A GG genotype was inversely associated with risk of pancreatic cancer (AOR, 0.21; 95% CI, 0.07-0.62). Three NR5A2 variants that were previously identified in a genome-wide association study were significantly associated with reduced risk of pancreatic cancer, AORs ranging from 0.57 to 0.79. Two FTO gene variants and one ADIPOQ variant were differentially associated with pancreatic cancer according to levels of body mass index (BMI; P(interaction) = 0.0001, 0.0015, and 0.03). For example, the AOR (95% CI) for FTO IVS1-2777AC/AA genotype was 0.72 (0.55-0.96) and 1.54 (1.14-2.09) in participants with a BMI of less than 25 or 25 kg/m(2) or more, respectively. We observed no significant association between AMPK genotype and pancreatic cancer and no genotype interactions with diabetes or smoking.

CONCLUSION

Our findings suggest the PPARγ P12A GG genotype and NR5A2 variants may reduce the risk for pancreatic cancer. A positive association of FTO and ADIPOQ gene variants with pancreatic cancer may be limited to persons who are overweight.

IMPACT

The discovery of genetic factors modifying the risk of pancreatic cancer may help to identify high-risk individuals for prevention efforts.

Body mass index and obesity- and diabetes-associated genotypes and risk for pancreatic cancer

BACKGROUND

The genetic factors predisposing individuals with obesity or diabetes to pancreatic cancer have not been identified.

AIMS

To investigate the hypothesis that obesity- and diabetes-related genes modify the risk of pancreatic cancer.

METHODS

We genotyped 15 single nucleotide polymorphisms of fat mass and obesity-associated (FTO), peroxisome proliferators-activated receptor gamma (PPARγ), nuclear receptor family 5 member 2 (NR5A2), AMPK, and ADIPOQ genes in 1,070 patients with pancreatic cancer and 1,175 cancer-free controls. Information on risk factors was collected by personal interview. Adjusted ORs (AOR) and 95% CIs were calculated using unconditional logistic regression.

RESULTS

The PPARγ P12A GG genotype was inversely associated with risk of pancreatic cancer (AOR, 0.21; 95% CI, 0.07-0.62). Three NR5A2 variants that were previously identified in a genome-wide association study were significantly associated with reduced risk of pancreatic cancer, AORs ranging from 0.57 to 0.79. Two FTO gene variants and one ADIPOQ variant were differentially associated with pancreatic cancer according to levels of body mass index (BMI; P(interaction) = 0.0001, 0.0015, and 0.03). For example, the AOR (95% CI) for FTO IVS1-2777AC/AA genotype was 0.72 (0.55-0.96) and 1.54 (1.14-2.09) in participants with a BMI of less than 25 or 25 kg/m(2) or more, respectively. We observed no significant association between AMPK genotype and pancreatic cancer and no genotype interactions with diabetes or smoking.

CONCLUSION

Our findings suggest the PPARγ P12A GG genotype and NR5A2 variants may reduce the risk for pancreatic cancer. A positive association of FTO and ADIPOQ gene variants with pancreatic cancer may be limited to persons who are overweight.

IMPACT

The discovery of genetic factors modifying the risk of pancreatic cancer may help to identify high-risk individuals for prevention efforts.

Association of ADIPOQ gene variants with body weight, type 2 diabetes and serum adiponectin concentrations: the Finnish Diabetes Prevention Study

BACKGROUND

Adiponectin, secreted mainly by mature adipocytes, is a protein with insulin-sensitising and anti-atherogenic effects. Human adiponectin is encoded by the ADIPOQ gene on the chromosomal locus 3q27. Variations in ADIPOQ are associated with obesity, type 2 diabetes (T2DM) and related phenotypes in several populations. Our aim was to study the association of the ADIPOQ variations with body weight, serum adiponectin concentrations and conversion to T2DM in overweight subjects with impaired glucose tolerance. Moreover, we investigated whether ADIPOQ gene variants modify the effect of lifestyle changes on these traits.

METHODS

Participants in the Finnish Diabetes Prevention Study were randomly assigned to a lifestyle intervention group or a control group. Those whose DNA was available (n = 507) were genotyped for ten ADIPOQ single nucleotide polymorphisms (SNPs). Associations between SNPs and baseline body weight and serum adiponectin concentrations were analysed using the univariate analysis of variance. The 4-year longitudinal weight data were analysed using linear mixed models analysis and the change in serum adiponectin from baseline to year four was analysed using Kruskal-Wallis test. In addition, the association of SNPs with the risk of developing T2DM during the follow-up of 0-11 (mean 6.34) years was analysed by Cox regression analysis.

RESULTS

rs266729, rs16861205, rs1501299, rs3821799 and rs6773957 associated significantly (p < 0.05) with body weight at baseline and in the longitudinal analyses. The rs266729 C allele and the rare minor alleles of rs2241766 and rs2082940 were associated with an increased adjusted hazard ratio of developing T2DM. The differences in baseline serum adiponectin concentrations were seen according to rs16861210, rs17366568, rs2241766, rs6773957 and rs2082940 and differences in the change of serum adiponectin levels from baseline to the four year examination were seen according to rs16861205, especially in subjects who were able to lose weight during the first year of intervention.

CONCLUSIONS

These results from the Finnish Diabetes Prevention Study support the concept that genetic variation in ADIPOQ locus contributes to variation in body size and serum adiponectin concentrations and may also modify the risk of developing T2DM.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov NCT00518167.

Genetic variation in adiponectin (ADIPOQ) and the type 1 receptor (ADIPOR1), obesity and prostate cancer in African Americans

Background

Adiponectin is a protein derived from adipose tissue suspected to play an important role in prostate carcinogenesis. Variants in the adiponectin gene (ADIPOQ) and its type I receptor (ADIPOR1) have been recently linked to risk of both breast and colorectal cancer. Therefore, we set out to examine the relationship between polymorphisms in these genes, obesity and prostate cancer in study of African American men.

Methods

Ten single nucleotide polymorphisms (SNPs) in ADIPOQ and ADIPOR1 were genotyped in DNA samples from 131 African American prostate cancer cases and 344 controls participating in the Flint Men's Health Study. Logistic regression was then used to estimate their association with prostate cancer and obesity.

Results

While no significant associations were detected between any of the tested SNPs and prostate cancer, the rs1501299 SNP in ADIPOQ was significantly associated with body mass (p=0.03).

Conclusions

Genetic variation in ADIPOQ and ADIPOR1 did not predict risk of prostate cancer in this study of African American men. However, the rs1501299 SNP in ADIPOQ was associated with obesity. Further investigation is warranted to determine if racial differences exist in the influence of the adiponectin pathway on prostate cancer risk.

A common variant in the adiponectin gene on weight loss and body composition under sibutramine therapy in obesity

In this study, we aimed to explore whether a common single nucleotide polymorphism (SNP), rs266729 (-11,377C > G), in the adiponectin C1Q and collagen domain containing (ADIPOQ) gene could influence weight reduction and fat change under sibutramine therapy in an obese population. There were 131 obese Taiwanese patients, including 44 in the placebo group and 87 in the sibutramine (10 mg daily) group. We assessed the measures of weight loss and body fat reduction at the end of the 12-week treatment period by analysis of covariance (ANCOVA) models using gender, baseline weight, and baseline percent body fat as covariates. By comparing the placebo and sibutramine groups with ANCOVA, our data revealed a strong effect of sibutramine on percent body fat loss (1.9 ± 0.3 vs 4.6 ± 0.5%; P < 0.001) and on weight reduction (2.8 ± 2.0 vs 7.9 ± 1.6 kg; P < 0.001) for subjects with the CC genotype. On the contrary, sibutramine had no significant effect on percent body fat loss or on weight loss in the GG and GC individuals. The results suggest that the SNP rs266729 of the ADIPOQ gene may contribute to weight reduction and fat loss in response to sibutramine therapy in Taiwanese obese patients.

Genetic architecture of plasma adiponectin overlaps with the genetics of metabolic syndrome-related traits

OBJECTIVE

Adiponectin, a hormone secreted by adipose tissue, is of particular interest in metabolic syndrome, because it is inversely correlated with obesity and insulin sensitivity. However, it is not known to what extent the genetics of plasma adiponectin and the genetics of obesity and insulin sensitivity are interrelated. We aimed to evaluate the heritability of plasma adiponectin and its genetic correlation with the metabolic syndrome and metabolic syndrome-related traits and the association between these traits and 10 ADIPOQ single nucleotide polymorphisms (SNPs).

RESEARCH DESIGN AND METHODS

We made use of a family-based population, the Erasmus Rucphen Family study (1,258 women and 967 men). Heritability analysis was performed using a polygenic model. Genetic correlations were estimated using bivariate heritability analyses. Genetic association analysis was performed using a mixed model.

RESULTS

Plasma adiponectin showed a heritability of 55.1%. Genetic correlations between plasma adiponectin HDL cholesterol and plasma insulin ranged from 15 to 24% but were not significant for fasting glucose, triglycerides, blood pressure, homeostasis model assessment of insulin resistance (HOMA-IR), and C-reactive protein. A significant association with plasma adiponectin was found for ADIPOQ variants rs17300539 and rs182052. A nominally significant association was found with plasma insulin and HOMA-IR and ADIPOQ variant rs17300539 after adjustment for plasma adiponectin.

CONCLUSIONS

The significant genetic correlation between plasma adiponectin and HDL cholesterol and plasma insulin should be taken into account in the interpretation of genome-wide association studies. Association of ADIPOQ SNPs with plasma adiponectin was replicated, and we showed association between one ADIPOQ SNP and plasma insulin and HOMA-IR.

Pathomechanisms of type 2 diabetes genes

Type 2 diabetes mellitus is a complex metabolic disease that is caused by insulin resistance and beta-cell dysfunction. Furthermore, type 2 diabetes has an evident genetic component and represents a polygenic disease. During the last decade, considerable progress was made in the identification of type 2 diabetes risk genes. This was crucially influenced by the development of affordable high-density single nucleotide polymorphism (SNP) arrays that prompted several successful genome-wide association scans in large case-control cohorts. Subsequent to the identification of type 2 diabetes risk SNPs, cohorts thoroughly phenotyped for prediabetic traits with elaborate in vivo methods allowed an initial characterization of the pathomechanisms of these SNPs. Although the underlying molecular mechanisms are still incompletely understood, a surprising result of these pathomechanistic investigations was that most of the risk SNPs affect beta-cell function. This favors a beta-cell-centric view on the genetics of type 2 diabetes. The aim of this review is to summarize the current knowledge about the type 2 diabetes risk genes and their variants' pathomechanisms.