Interactions between noncontiguous haplotypes in the adiponectin gene ACDC are associated with plasma adiponectin

Serum adiponectin levels and adiponectin +276 G/T gene polymorphism in newborns with large and small birth weights

PURPOSE

Adiponectin may be an important indicator in the regulation of fetal and neonatal growth due to its metabolism, energy balance, and insulin-sensitizing action. The current study's goal was to determine if there is a link between adiponectin +276 G/T gene polymorphism and serum adiponectin level in newborns classified as appropriate for gestational age (AGA), small for gestational age (SGA), or large for gestational age (LGA).

METHODS

The study included newborns classified as AGA (n = 65), SGA (n = 65), or LGA (n = 65) according to their gestational age or birth weight. To determine the presence of adiponectin +276 G/T gene polymorphism, genotyping was done using polymerase chain reaction-restriction fragment length polymorphism. Enzyme-linked immunosorbent assay was used to determine the level of adiponectin in the blood.

RESULTS

The SGA newborns had significantly lower levels of serum adiponectin than the AGA and LGA newborns. There were statistically significant differences between the genotype frequencies (GG, GT, TT) of the SGA newborns (29.9%, 45.1%, 13.9%), the AGA newborns (41.6%, 20.7%, 44.4%), and the LGA newborns (28.6%, 34.1%, 41.7%) (chi-square = 15.8; degree of freedom = 4; p = .003). The newborns carrying the GT genotype had an increased risk of being SGA compared to those carrying the GG and TT genotypes (odds ratio [OR] = 3.07; confidence interval [CI] = 95% (1.38-6.64); p = .005 and OR = 6.96; CI = 95% (2.19-22.1); p < .001, respectively). The newborns carrying the GG and TT genotypes had better protection against being SGA than those carrying the GT genotype (OR = 0.33; CI = 95% (0.15-0.72); p = .005 and OR = 0.14; CI = 95% (0.05-0.46); p < .001, respectively). The newborns carrying the GT genotype had lower birth weights, head circumferences, and ponderal indices than those carrying the TT genotype (p < .001). The serum adiponectin levels between adiponectin +276 G/T genotypes did not differ significantly (p = .429). In addition, serum adiponectin level showed a significant positive correlation with birth weight, birth length, head circumference, and ponderal index in all newborns.

CONCLUSION

The results of the current study suggest that the adiponectin +276 G/T gene polymorphism was associated with an increased chance of being born SGA or LGA. The effect of this polymorphism on newborn birth size was independently associated with serum adiponectin levels. Adiponectin may play a role in fetal growth.

Association of maternal dietary habits and ADIPOQ gene polymorphisms with the risk of congenital heart defects in offspring: a hospital-based case-control study

OBJECTIVES

To estimate the association of maternal ADIPOQ gene, dietary habits in early pregnancy, and their interactions with the risk of congenital heart defects (CHDs) in offspring.

METHODS

A case-control study of 464 mothers of CHDs children and 504 mothers of healthy children was included. Maternal dietary habits and genetic polymorphisms of ADIPOQ were the main exposure of interest. Their independent effects and interactions in the development of CHDs were analyzed in our study.

RESULTS

The excessive consumption of pickled vegetables (aOR = 1.58, 95%CI: 1.17-2.12), smoked foods (aOR = 1.84, 95%CI:1.34-2.52), barbecued foods (aOR = 1.62, 95%CI: 1.09-2.39), fish and shrimp (aOR = 0.37, 95%CI: 0.27-50), and milk products (aOR = 0.64, 95%CI: 0.51-80) had a significant association with total CHDs risk. The polymorphisms of ADIPOQ gene at rs1501299 (T/T vs G/G: aOR = 0.27, 95%CI: 0.14-50; G/T vs G/G: aOR = 0.67, 95%CI: 0.46-98) and rs2241766 (G/G vs T/T: aOR = 4.35, 95%CI: 2.23-8.51; T/G vs T/T: aOR = 2.23, 95%CI: 1.51-3.28) showed a significant association with total CHDs risk. Likewise, our results found that maternal dietary habits and ADIPOQ genetic variants also were significantly related to the risk of specific CHDs phenotypes. In addition, gene-diet interaction revealed significant associations between the ADIPOQ gene and maternal dietary habits with total CHDs.

CONCLUSIONS

Maternal dietary habits, ADIPOQ gene, and their interactions show a significant association with the risk of CHDs. However, our study has some limitations, thus our findings need to be taken with caution, which highlights that more studies are required to further corroborate our findings.

Association of Candidate Gene Polymorphism with Metabolic Syndrome among Mongolian Subjects: A Case-Control Study

Metabolic syndrome (MetS) is complex and determined by the interaction between genetic and environmental factors and their influence on obesity, insulin resistance, and related traits associated with diabetes and cardiovascular disease risk. Some dynamic markers, including adiponectin (ADIPOQ), brain-derived neurotrophic factor (BDNF), and lipoprotein lipase (LPL), are implicated in MetS; however, the influence of their genetic variants on MetS susceptibility varies in racial and ethnic groups. We investigated the association of single nucleotide polymorphism (SNP)-SNP interactions among nine SNPs in six genes with MetS's genetic predisposition in Mongolian subjects. A total of 160 patients with MetS for the case group and 144 healthy individuals for the control group were selected to participate in this study. Regression analysis of individual SNPs showed that the ADIPOQ + 45GG (odds ratio (OR) = 2.09, p = 0.011) and P⁺P⁺ of LPL PvuII (OR = 2.10, p = 0.038) carriers had an increased risk of MetS. Conversely, G allele of LPL S447X (OR = 0.45, p = 0.036) and PGC-1α 482Ser (OR = 0.26, p = 0.001) allele were estimated as protective factors, respectively. Moreover, a haplotype containing the G-P⁺-G combination was related to MetS. Significant loci were also related to body mass index (BMI), systolic blood pressure (SBP), serum high-density lipoprotein cholesterol (HDL-C), triglyceride (TG), and fasting blood glucose (FBG), adipokines, and insulin as well as insulin resistance (p < 0.05). Our results confirm that ADIPOQ + 45T > G, LPL PvII, and PGC-1α Gly482Ser loci are associated with MetS in Mongolian subjects.

Adipokine Gene Single-Nucleotide Polymorphisms in Portuguese Obese Adolescents: Associations with Plasma Concentrations of Adiponectin, Resistin, IL-6, IL-1β, and TNF-α

BACKGROUND

The genetic contribution to obesity and to circulating adipokine levels has not been completely clarified. We aimed to evaluate adipokine genes' single-nucleotide polymorphism (SNP) prevalence and its association with circulating adipokine levels and risk factors for cardiovascular disease in an obese Portuguese pediatric population.

METHODS

Two hundred forty-eight obese adolescents (mean age 13.4 years old; 47.2% females) participated in a cohort study. We screened 12 SNPs by direct sequencing in five adipokine genes: adiponectin (ADIPOQ: rs16861194, rs17300539, rs266729, rs2241766, rs1501299), interleukin-1β (IL-1β; rs1143627), IL-6 (IL-6; rs1800795), tumor necrosis factor-α (TNF-α; rs1800629), and resistin (RETN; rs1862513, rs3219177, rs3745367, rs3745368). Biochemical analysis included determination of circulating adipokines, C-reactive protein (CRP) levels, lipid profile, and markers of insulin resistance.

RESULTS

Compared to males, females presented higher circulating levels of insulin, adiponectin, IL-6, resistin, and leptin concentrations, but lower TNF-α levels. No statistically significant differences were found for genotype or allelic distributions between genders. In the whole sample population, adiponectin levels were influenced by ADIPOQ rs17300539 (c.-1138G>A; lower in subjects with GG genotype). When only males were considered, IL-1β, IL-6, and TNF-α levels were associated with ADIPOQ rs1501299 (c.214 + 62G>T; higher in GG subjects). TNF-α concentrations were modulated by TNF-α rs1800629 (c.-488G>A; lower in GG males), RETN rs1862513 (c.-216C>G; higher in CC subjects), and RETN rs3219177 (c.118 + 39C>T; higher in CC subjects). Leptin levels were influenced by IL-1β rs1143627 (c.-118C>T) presenting TT individuals' lower levels.

CONCLUSIONS

Our data demonstrate that in pediatric obese patients, some adipokine gene SNPs have an association with circulating adipokine levels and lipid profile.

Genetic and Non-Genetic Determinants of Circulating Levels of Adiponectin in a Cohort of Chilean Subjects

BACKGROUND

Low adiponectin levels have been associated with obesity, diabetes, coronary disease and polymorphisms. The aim of this study was to assess the clinical and genetic factors related to adiponectin levels in a Chilean adult population.

METHODS

Four groups of 27 individuals, stratified by gender and abdominal obesity, were included in this cross-sectional study. Physical activity level, cardiovascular risk factors and therapy were assessed. Anthropometric measurements, adiponectin, glucose, insulin, hs-CRP, rs1501299, rs2241766, rs266729 and rs17300539 single nucleotide polymorphisms of the adiponectin gene were determined.

RESULTS

Adiponectin levels were inversely correlated with waist circumference, waist-to-hip ratio, weight, body mass index, insulin levels, homeostasis model insulin resistance index (HOMA-IR) and physical activity. Mean adiponectin levels were lower in men (10.1 ± 3.6 vs 11.9 ± 2.9 μg/mL, p = 0.0051), obese (9.9 ± 3.2 vs 12.1 ± 3.3, p < 0.01), physically inactive (8.9 ± 3.2 vs 11.0 ± 2.8, p = 0.015) and insulin-resistant individuals (10.2 ± 3.1 vs 12.9 ± 3.9; p = 0.005). Adiponectin levels were lower in subjects with GG genotype (rs1501299) compared with those with TT or GT variants (6.9 ± 4.6 vs 12.2 ± 2.9 and 11.5 ± 3.4 μg/mL, p = 0.006) but were similar in the other polymorphisms studied.

CONCLUSION

Lower adiponectin levels were related to gender, abdominal obesity, physical activity and insulin resistance and were less influenced by the polymorphisms studied.

Genetic polymorphisms associated with overweight and obesity in uncontrolled Type 2 diabetes mellitus

Generally, obese and overweight individuals display higher free fatty acid levels, which stimulate insulin resistance. The combination of overweight or obesity with insulin resistance can trigger Type 2 diabetes mellitus (T2DM) and are primary contributing factors to the development of uncontrolled T2DM. Genetic polymorphisms also play an important role as they can impact a population's susceptibility to becoming overweight or obese and developing related chronic complications, such as uncontrolled T2DM. This review specifically examines the genetic polymorphisms associated with overweight and obesity in patients with uncontrolled T2DM. Particularly, gene polymorphisms in ADIPOQ (rs1501299 and rs17300539), LepR (rs1137101 and rs1045895), IRS2 (rs1805092), GRB14 (rs10195252 and rs3923113) and PPARG (rs1801282) have been associated with overweight and obesity in uncontrolled T2DM.

Effect of adiponectin-encoding gene ADIPOQ single nucleotide polymorphisms +45 and +276 on serum lipid levels after antiretroviral therapy in Japanese patients with HIV-1-infection

Objectives

To investigate the association between single nucleotide polymorphisms (SNPs) in the adiponectin-encoding gene ADIPOQ and changes in serum lipid levels in HIV-1-infected patients after antiretroviral therapy (ART).

Methods

ART-naïve HIV-1-infected patients were recruited to this prospective analysis. SNP +45 and SNP +276 genotype was determined by direct sequencing. Multivariate linear regression analysis was performed to analyse the effects of genotype, and predisposing conditions on serum total cholesterol and triglyceride in the 4 months before and after ART initiation.

Results

The study enrolled 78 patients with HIV-1-infection (73 male, five female; age range 22–67 years). HIV-1 viral load ≥5 log₁₀ copies/ml, baseline total cholesterol ≥160 mg/dl, and CD4⁺ lymphocyte count <200/µl were associated with increased serum total cholesterol levels after ART initiation. Protease inhibitor treatment and body mass index ≥25 kg/m² were associated with increased triglyceride levels after ART initiation. There were no significant associations between SNP +45 or SNP +276 genotype and serum total cholesterol or triglyceride levels.

Conclusions

SNP +45 and SNP +276 genotype is not associated with changes in serum total cholesterol or triglyceride levels after ART initiation.

Gender-specific associations between ADIPOQ gene polymorphisms and adiponectin levels and obesity in the Jackson Heart Study cohort

BACKGROUND

Despite the important role of adiponectin in regulating general metabolic homeostasis, analysis of genetic determinants of adiponectin and the related cardio-metabolic traits in African American population has been limited and inconsistent. Considering the high genetic admixture of African Americans and thus the important population stratification that may confound the genetic-trait associations, the objective of this work was to perform a comprehensive analysis of the associations between ADIPOQ variants and adiponectin levels and obesity phenotypes in a large African American population from the Jackson Heart Study (JHS) cohort.

METHODS

Genotype data was available for 2968 JHS participants (1131men; 1837women). Single Nucleotide Polymorphisms (SNPs) were selected by a Tag-SNP Approach and literature review. The genotype imputation was performed using IMPUTE2 software and reference phased data from the 1000G project. PLINK software was used for the genetic analysis. Plasma specimens were analyzed by ELISA for adiponectin levels. All analyses were controlled for population stratification assessed by Individual Proportions of European Ancestry (PEA) estimates calculated in HAPMIX using ancestry informative markers (AIMs).

RESULTS

We found a gender-dependent association of some ADIPOQ variants and adiponectin levels. In women four of the studied polymorphisms (rs6444174, rs16861205, rs1403697, rs7641507) were associated with adiponectin levels after Bonferroni correction and controlling for the percentage of PEA, age, annual household income and smoking. These results were consistent with the haplotype analysis. The association between the rs12495941 variant and obesity is modulated by the PEA, so that the relationship between the G allele and a higher incidence of obesity was present in those individuals within the lower PEA group. In addition we found an effect modification of obesity on the association between the ADIPOQ rs6444174 SNP and BMI so that the presence of the T allele was negatively and significantly associated with BMI only in participants with a normal weight.

CONCLUSIONS

In this large African American cohort, ADIPOQ variants were associated with adiponectin levels in a gender-dependent manner and the relationship of some of these variants with obesity and BMI was modulated by the PEA and obesity status respectively. This suggests that the effects of these polymorphisms on adiponectin and obesity phenotypes are subject to a strong interaction with genetic and environmental factors in African American population.

Relationship between adiponectin and fertility in the female pig

Adiponectin isoforms may mediate different aspects of the pleiotropic function of the protein, including the reproductive process. We examined the pattern of circulating adiponectin and adiponectin system expression in fat and ovarian tissues of hyperfertile and subfertile sows. We demonstrated the presence of five different isoforms of adiponectin (90, 158, 180, 250 and >250 kDa) in the circulation and identified a subgroup of subfertile females that displayed reduced abundance of all adiponectin isoforms as well as a lack of the 250-kDa adiponectin isoform in both serum and follicular fluid. Subfertility in these animals was associated with fewer large follicles and corpora lutea in the ovaries, as well as lower concentrations of 17β-oestradiol in the follicular fluid of large follicles. In addition, subfertile females showed higher adiponectin mRNA in fat tissue and altered mRNA and protein expression of adiponectin and its receptors in the ovary. Changes in the abundance and pattern of circulating adiponectin isoforms have been associated with reproductive disorders in animals and humans, including polycystic ovarian syndrome (PCOS). Our findings suggest that the adiponectin system may play an important role in controlling ovarian function and influencing porcine fertility.

New insight into adiponectin role in obesity and obesity-related diseases

Obesity is a major health problem strongly increasing the risk for various severe related complications such as metabolic syndrome, cardiovascular diseases, respiratory disorders, diabetic retinopathy, and cancer. Adipose tissue is an endocrine organ that produces biologically active molecules defined “adipocytokines,” protein hormones with pleiotropic functions involved in the regulation of energy metabolism as well as in appetite, insulin sensitivity, inflammation, atherosclerosis, cell proliferation, and so forth. In obesity, fat accumulation causes dysregulation of adipokine production that strongly contributes to the onset of obesity-related diseases. Several advances have been made in the treatment and prevention of obesity but current medical therapies are often unsuccessful even in compliant patients. Among the adipokines, adiponectin shows protective activity in various processes such as energy metabolism, inflammation, and cell proliferation. In this review, we will focus on the current knowledge regarding the protective properties of adiponectin and its receptors, AdipoRs (“adiponectin system”), on metabolic complications in obesity and obesity-related diseases. Adiponectin, exhibiting antihyperglycemic, antiatherogenic, and anti-inflammatory properties, could have important clinical benefits in terms of development of therapies for the prevention and/or for the treatment of obesity and obesity-related diseases.

Association between 276G/T adiponectin gene polymorphism and new-onset diabetes after kidney transplantation

BACKGROUND

New-onset diabetes after transplantation (NODAT) is a well-recognized complication of kidney transplantation and is associated with poor outcomes. Both adiponectin and chemokine ligand 5 (CCL5) proteins are related to glucose metabolism and genetic variations in their genes can lead to development of NODAT. The aim of this study was to investigate the association of adiponectin and CCL5 genes polymorphisms with NODAT in a population of Caucasian kidney transplant recipients.

METHODS

Two hundred seventy Caucasian kidney transplant recipients (83 with NODAT and 187 without NODAT) were included in a nested case-control study. Patients with pretransplantation diabetes mellitus and multiorgan transplantation were excluded. NODAT diagnosis was determined by American Diabetes Association criteria. Subjects were genotyped for 276G/T adiponectin gene polymorphism (rs1501299) and rs2280789 and rs3817655 CCL5 gene polymorphisms by real-time polymerase chain reaction.

RESULTS

The TT genotype of 276G/T adiponectin gene polymorphism was significantly more frequent in NODAT than non-NODAT patients compared with GG/GT genotypes (recessive model; P=0.031). TT genotype was identified as an independent risk factor for NODAT in Caucasian kidney transplant recipients after adjusting for age at transplantation, pretransplantation body mass index, and use of tacrolimus (TT vs. GG/GT, hazard ratio=1.88, 95% confidence interval=1.03-3.45, P=0.041). There were no differences in genotype distribution and allele frequency of rs2280789 and rs3817655 CCL5 gene polymorphisms between NODAT and non-NODAT groups.

CONCLUSIONS

The 276G/T adiponectin gene polymorphism is associated with NODAT in Caucasian kidney transplant recipients.

Current clinical evidence on pioglitazone pharmacogenomics

Pioglitazone is the most widely used thiazolidinedione and acts as an insulin-sensitizer through activation of the Peroxisome Proliferator-Activated Receptor-γ (PPARγ). Pioglitazone is approved for use in the management of type 2 diabetes mellitus (T2DM), but its use in other therapeutic areas is increasing due to pleiotropic effects. In this hypothesis article, the current clinical evidence on pioglitazone pharmacogenomics is summarized and related to variability in pioglitazone response. How genetic variation in the human genome affects the pharmacokinetics and pharmacodynamics of pioglitazone was examined. For pharmacodynamic effects, hypoglycemic and anti-atherosclerotic effects, risks of fracture or edema, and the increase in body mass index in response to pioglitazone based on genotype were examined. The genes CYP2C8 and PPARG are the most extensively studied to date and selected polymorphisms contribute to respective variability in pioglitazone pharmacokinetics and pharmacodynamics. We hypothesized that genetic variation in pioglitazone pathway genes contributes meaningfully to the clinically observed variability in drug response. To test the hypothesis that genetic variation in PPARG associates with variability in pioglitazone response, we conducted a meta-analysis to synthesize the currently available data on the PPARG p.Pro12Ala polymorphism. The results showed that PPARG 12Ala carriers had a more favorable change in fasting blood glucose from baseline as compared to patients with the wild-type Pro12Pro genotype (p = 0.018). Unfortunately, findings for many other genes lack replication in independent cohorts to confirm association; further studies are needed. Also, the biological functionality of these polymorphisms is unknown. Based on current evidence, we propose that pharmacogenomics may provide an important tool to individualize pioglitazone therapy and better optimize therapy in patients with T2DM or other conditions for which pioglitazone is being used.

Association of Adiponectin Gene Polymorphism With Birth Weight in Korean Neonates

Adiponectin has been associated with insulin resistance and type 2 diabetes mellitus and possibly fetal growth. Our aim was to assess the association between the single nucleotide polymorphisms (SNPs) of the adiponectin gene (ADIPOQ) and the birth sizes. We investigated four SNPs of ADIPOQ (rs182052, rs2241766, rs1501299, and rs266729) and birth height and weight in 237 healthy full-term neonates. The neonates with the rs182052 G allele had a greater birth weight (p = .043 in the dominant model) and a higher ponderal index (p = .028 in the additive model). The rs2241766 G allele was associated with a greater birth weight (p = .016 in the recessive model). In a logistic regression analysis, the homozygotes for the rs182052 G allele and those for the rs2241766 G allele showed a significant association with a greater birth weight above 90 percentile (OR 2.75, 95% CI 1.13–6.70 and OR 5.15, 95% CI 1.66–15.99, respectively). In conclusion, we found an association between rs182052 and rs2241766 and birth weight and ponderal index among healthy neonates and suggested that adiponectin might have some roles in fetal growth.

Novel variations in the adiponectin gene (ADIPOQ) may affect distribution of oligomeric complexes

Adiponectin is an obesity related protein that mediates the risk of type 2 diabetes in obese individuals with its anti-inflammatory and insulin-sensitizing properties. To date, five functional variations have been identified in the adiponectin gene. However, these variations are rare, and fail to fully explain adiponectin variability, suggesting unidentified causal variations exist. Thus, our objective was to identify novel, potentially functional amino acid-changing variations in ADIPOQ exonic regions and relate them to oligomeric forms of adiponectin in serum. We sequenced ADIPOQ exons in 30 adolescents chosen from a school-based cohort based on serum adiponectin and insulin levels. Four coding region changes were identified: a methionine initiation skip (MIS), P32L, R55C, and Y111H, of which R55C and Y111H have been previously identified. Individuals with the novel variations and R55C had low levels of adiponectin and decreased adiponectin oligomerization compared to adolescents with similar body mass index and insulin levels. Further, bioinformatic analysis predicted putative functionality of these variations. In our study, Y111H was unrelated to total circulating adiponectin or adiponectin oligomerization. Given the disruption of adiponectin oligomerization in the individuals with MIS, P32L, and R55C coding changes, these variations may lead to increased metabolic disease risk and warrant further examination in larger cohorts.

Genetic variations in ADIPOQ gene are associated with chronic obstructive pulmonary disease

BACKGROUND

Adiponectin is reported to be related to the development of chronic obstructive pulmonary disease (COPD). Genetic variants in the gene encoding adiponectin (ADIPOQ) have been reported to be associated with adiponectin level in several genome-wide linkage and association studies. However, relatively little is known about the effects of ADIPOQ gene variants on COPD susceptibility. We determined the frequencies of single-nucleotide polymorphisms (SNPs) in ADIPOQ in a Chinese Han population and their possible association with COPD susceptibility.

METHODS

We conducted a case-control study of 279 COPD patients and 367 age- and gender-distribution-matched control subjects. Seven tagging SNPs in ADIPOQ, including rs710445, rs16861205, rs822396, rs7627128, rs1501299, rs3821799 and rs1063537 were genotyped by SNaPshot. Association analysis of genotypes/alleles and haplotypes constructed from these loci with COPD was conducted under different genetic models.

RESULTS

The alleles or genotypes of rs1501299 distributed significantly differently in COPD patients and controls (allele: P = 0.002, OR = 1.43 and 95%CI = 1.14-1.79; genotype: P = 0.008). The allele A at rs1501299 was potentially associated with an increased risk of COPD in all dominant model analysis (P = 0.009; OR: 1.54; 95%CI: 1.11-2.13), recessive model analyses (P = 0.015; OR: 1.75; 95% CI: 1.11-2.75) and additive model analyses (P = 0.003; OR: 2.11; 95% CI: 1.29-3.47). In haplotype analysis, we observed haplotypes AAAAACT and GGACCTC had protective effects, while haplotypes AGAACTC, AGGCCTC, GGAACTC, GGACACT and GGGCCTC were significantly associated with the increased risk of COPD.

CONCLUSIONS

We conducted the first investigation of the association between the SNPs in ADIPOQ and COPD risk. Our current findings suggest that ADIPOQ may be a potential risk gene for COPD. Further studies in larger groups are warranted to confirm our results.

Association of ADIPOQ +45T>G polymorphism with body fat mass and blood levels of soluble adiponectin and inflammation markers in a Mexican-Mestizo population

PURPOSE

Obesity is a disease with genetic susceptibility characterized by an increase in storage and irregular distribution of body fat. In obese patients, the decrease in the Adiponectin gene (ADIPOQ) expression has been associated with a systemic low-grade inflammatory state. Our aim was to investigate the relationship between ADIPOQ +45T>G gene simple nucleotide polymorphism (SNP rs2241766) with serum adiponectin (sAdiponectin), distribution of body fat storage, and inflammation markers.

SUBJECTS AND METHODS

In this cross-sectional study, 242 individuals from Western Mexico characterized as Mexican-Mestizo and classified by body mass index (BMI), were included. Anthropometrics, body composition, body fat distribution, and inflammation markers were measured by routine methods. Genotypes were characterized using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique and sAdiponectin by the ELISA method. A P-value <0.05 was considered the statistically significant threshold.

RESULTS

sAdiponectin is associated with BMI (P < 0.001) and the genotypes (P < 0.001 to 0.0046) GG (8169 ± 1162 ng/mL), TG (5189 ± 501 ng/mL), and TT (3741 ± 323 ng/mL), but the SNP ADIPOQ +45T>G is not associated with BMI. However, the detailed analysis showed association of this SNP with a pattern of fat distribution and correlations (P < 0.05) with inflammation markers and distribution of body fat storage (Pearson's r = -0.169 to -0.465) were found.

CONCLUSION

In this study, we have suggested that the ADIPOQ +45G allele could be associated with distribution of body fat storage in obesity. On the other hand, as no association was observed between ADIPOQ +45T>G gene polymorphism and obesity, it cannot be concluded that the ADIPOQ +45G allele is responsible for the increase of adiponectin levels.

Association of adiponectin gene polymorphism (+T45G) with acute coronary syndrome and circulating adiponectin levels

We investigated the association of adiponectin gene polymorphisms (+T45G and +G276T) and adiponectin levels with acute coronary syndrome (ACS) among Arabs in Qatar. A case-control study was performed in 142 Arab patients with ACS and 122 controls. Genotypes were determined using TaqMan real-time polymerase chain reaction assay. The TT, TG, and GG genotype frequencies of the T45G variant were significantly different among cases and controls (P = .023) but not significant for G276T genotypic frequencies. It was found that only the +45G allele was significantly associated with 3-fold increased risk of ACS (odds ratio = 2.77; 1.03-6.96; P = .043) among patients, using the genetic recessive model. Carriers of GG alleles had significantly lower adiponectin levels compared to TT/TG carriers of T45G in patients with ACS. The present study suggests that only T45G single-nucleotide polymorphism in the adiponectin gene is associated with higher odds for ACS events and has an effect on serum adiponectin levels among Arab populations.

Variants of the adiponectin and adiponectin receptor-1 genes and posttransplantation diabetes mellitus in renal allograft recipients

CONTEXT

Posttransplantation diabetes mellitus (PTDM) is a major metabolic complication in renal transplant recipients. Adiponectin (ADIPOQ) and adiponectin receptor-1 (ADIPOR1) gene polymorphisms have been associated with type 2 diabetes. However, it is unknown whether these polymorphisms are also risk factors for PTDM.

OBJECTIVE

We investigated the association between PTDM and single-nucleotide polymorphisms of ADIPOQ and ADIPOR1 in a cohort of renal allograft recipients.

DESIGN, SETTING, AND PARTICIPANTS

Five hundred seventy-five patients (367 men and 208 women) who received kidney transplants between 1989 and 2007, without a history of diabetes and with a pretransplant fasting glucose concentration less than 5.5 mmol/liter. Patients were followed up for a median 10 yr. Genotypes included single-nucleotide polymorphisms of the following: ADIPOQ rs266729, rs822395, rs822396, rs2241766, and rs1501299 and ADIPOR1 rs2232853, rs12733285, and rs1342387.

RESULTS

TT-homozygotes in ADIPOQ rs1501299 [hazard ratio (HR) = 1.70, P = 0.032] had greater risk of PTDM after adjusting for age, sex, amount of weight gain, and type of immunosuppressant. There was a significant interaction between sex and ADIPOQ rs1501299 genotype (P = 0.037). In men, but not in women, TT-homozygotes in ADIPOQ rs1501299 were more likely to develop PTDM than the wild GG-homozygotes (HR = 2.50, P = 0.002), whereas GT-heterozygotes had nonsignificantly elevated risk (HR = 1.41, P = 0.128).

CONCLUSION

Genetic variation in ADIPOQ rs1501299 is associated with PTDM in a sex-specific manner.

Genetic variants in ADIPOQ gene and the risk of type 2 diabetes: a case-control study of Chinese Han population

This study was to evaluate the association between ADIPOQ gene variants and type 2 diabetes mellitus (T2DM). TaqMan(®) assay was performed to test the genotypes in T2DM patients (n = 1,105) and normal control subjects (n = 1,107). Serum adiponectin concentration was measured by ELISA kit. The variant genotypes rs7649121AT and rs7649121AT/TT, compared with the AA genotype, were associated with a significantly decreased risk of T2DM [Adjusted OR (95% CI) = 0.79(0.66-0.95), 0.80(0.67-0.96), respectively]. In stratified analysis, rs2241767AG genotype increased the risk of T2DM in obesity group [Adjusted OR (95% CI) = 1.32(1.03-1.69)]. Patients with genotype AG/GG of rs2241767 had lower levels of serum adiponectin than those with the genotype AA (P = 0.044). Haplotype analyses were not significant. Crossover analysis of rs7649121 and environmental risk factor (obesity) indicated that the protect effect of rs7649121AT/TT maybe offset by the environmental risk. Those who exposed to environmental risk factor (obesity) had a chance to attack T2DM compared with those who did not expose to the two factors [Adjusted OR (95% CI) = 1.64(1.30-2.06)]. This study suggested that the ADIPOQ gene polymorphisms were associated with the risk of T2DM in a Chinese Han population.

Effect of interaction between PPARG, PPARA and ADIPOQ gene variants and dietary fatty acids on plasma lipid profile and adiponectin concentration in a large intervention study

Unsaturated fatty acids are ligands of PPAR-γ, which up-regulates genes involved in fatty acid transport and TAG synthesis and the insulin-sensitising adipokine adiponectin, which activates fatty acid β-oxidation via PPAR-α action in liver. We investigated the effect of dietary fatty acid interaction with PPARG, PPARA and ADIPOQ gene variants on plasma lipid and adiponectin concentrations in the Reading Imperial Surrey Cambridge King's study, a five-centre, parallel design, randomised controlled trial of 466 subjects at increased cardiometabolic risk. After a 4-week run-in to baseline, SFA was replaced by MUFA or carbohydrate (low fat) in isoenergetic diets for 24 weeks. Habitual dietary PUFA:SFA ratio×PPARG Pro12Ala genotype interaction influenced plasma total cholesterol (P=0·02), LDL-cholesterol (P=0·002) and TAG (P=0·02) concentrations in White subjects. PPARA Val162Leu×PPARG Pro12Ala genotype interaction influenced total cholesterol (P=0·04) and TAG (P=0·03) concentrations at baseline. After high-MUFA and low-fat diets, total cholesterol and LDL-cholesterol were reduced (P<0·001) and gene×gene interaction determined LDL-cholesterol (P=0·003) and small dense LDL as a proportion of LDL (P=0·012). At baseline, ADIPOQ -10066 G/A A-allele was associated with lower serum adiponectin (n 360; P=0·03) in White subjects. After the high-MUFA diet, serum adiponectin increased in GG subjects and decreased in A-allele carriers (P=0·006 for difference). In GG, adiponectin increased with age after the high MUFA and decreased after the low-fat diet (P=0·003 for difference at 60 years). In conclusion, in Whites, high dietary PUFA:SFA would help to reduce plasma cholesterol and TAG in PPARG Ala12 carriers. In ADIPOQ -10066 GG homozygotes, a high-MUFA diet may help to increase adiponectin with advancing age.

The adiponectin gene, ADIPOQ, and genetic susceptibility to colon cancer

In order to evaluate the contribution of polymorphisms of the adiponectin gene, ADIPOQ, to the risk of colon cancer, we conducted a case-control study of 60 colon cancer patients and 60 age, gender and ethnicity-matched controls in the Saudi population. We tested the hypothesis by analyzing the genotypes for two single nucleotide polymorphisms (SNPs), rs1501299 (G276T) and rs2241766 (T45G), in the ADIPOQ gene. In addition, the study was also designed to assess whether the two SNPs contribute to circulating adiponectin levels. We observed an increased risk of colon cancer associated with the 276T allele. The odds ratio (OR) was 2.64 [95% confidence interval (CI), 0.49-14.6]. The G allele at the T45G polymorphism was associated with a lower risk of colon cancer (OR=0.41; 95% CI, 0.19-0.86). Our results suggest that the risk of developing colon cancer may be partially explained by genetic polymorphisms in the ADIPOQ gene.

New type 2 diabetes risk genes provide new insights in insulin secretion mechanisms

Type 2 diabetes results from the inability of beta cells to increase insulin secretion sufficiently to compensate for insulin resistance. Insulin resistance is thought to result mainly from environmental factors, such as obesity. However, there is compelling evidence that the decline of both insulin sensitivity and insulin secretion have also a genetic component. Recent genome-wide association studies identified several novel risk genes for type 2 diabetes. The vast majority of these genes affect beta cell function by molecular mechanisms that remain unknown in detail. Nevertheless, we and others could show that a group of genes affect glucose-stimulated insulin secretion, a group incretin-stimulated insulin secretion (incretin sensitivity or secretion) and a group proinsulin-to-insulin conversion. The most important so far type 2 diabetes risk gene, TCF7L2, interferes with all three mechanisms. In addition to advancing knowledge in the pathophysiology of type 2 diabetes, the discovery of novel genetic determinants of diabetes susceptibility may help understanding of gene-environment, gene-therapy and gene-gene interactions. It was also hoped that it could make determination of the individual risk for type 2 diabetes feasible. However, the allelic relative risks of most genetic variants discovered so far are relatively low. Thus, at present, clinical criteria assess the risk for type 2 diabetes with greater sensitivity and specificity than the combination of all known genetic variants.

Single nucleotide polymorphisms at the ADIPOQ gene locus interact with age and dietary intake of fat to determine serum adiponectin in subjects at risk of the metabolic syndrome

BACKGROUND

Adiponectin gene expression is modulated by peroxisome proliferator-activated receptor γ, which is a transcription factor activated by unsaturated fatty acids.

OBJECTIVE

We investigated the effect of the interaction between variants at the ADIPOQ gene locus, age, sex, body mass index (BMI), ethnicity, and the replacement of dietary saturated fatty acids (SFAs) with monounsaturated fatty acids (MUFAs) or carbohydrates on serum adiponectin concentrations.

DESIGN

The RISCK (Reading, Imperial, Surrey, Cambridge, and Kings) study is a parallel-design, randomized controlled trial. Serum adiponectin concentrations were measured after a 4-wk high-SFA (HS) diet and a 24-wk intervention with reference (HS), high-MUFA (HM), and low-fat (LF) diets. Single nucleotide polymorphisms at the ADIPOQ locus -11391 G/A (rs17300539), -10066 G/A (rs182052), -7734 A/C (rs16861209), and +276 G/T (rs1501299) were genotyped in 448 participants.

RESULTS

In white Europeans, +276 T was associated with higher serum adiponectin concentrations (n = 340; P = 0.006) and -10066 A was associated with lower serum adiponectin concentrations (n = 360; P = 0.03), after adjustment for age, BMI, and sex. After the HM diet, -10066 G/G subjects showed a 3.8% increase (95% CI: -0.1%, 7.7%) and G/A+A/A subjects a 2.6% decrease (95% CI: -5.6%, 0.4%) in serum adiponectin (P = 0.006 for difference after adjustment for the change in BMI, age, and sex). In -10066 G/G homozygotes, serum adiponectin increased with age after the HM diet and decreased after the LF diet.

CONCLUSION

In white -10066 G/G homozygotes, an HM diet may help to increase adiponectin concentrations with advancing age. This trial was registered at clinicaltrials.gov as ISRCTN29111298.

Adiponectin level as a consequence of genetic variation, but not leptin level or leptin: adiponectin ratio, is a risk factor for carotid intima-media thickness

BACKGROUND AND PURPOSE

The adipocytokines adiponectin and leptin have been suggested as risk factors for cardiovascular disease, including stroke, acting through atherosclerosis. However, studies have provided conflicting results in underpowered cohorts with some suggesting that the leptin:adiponectin ratio is a better predictor of risk. We examined these associations with carotid intima-media thickness (IMT), a marker of early atherosclerosis and arterial remodeling and an independent predictor of stroke. We also examined association between genetic variants in the leptin and adiponectin genes and IMT.

METHODS

Adiponectin and leptin levels were determined in 990 individuals from the community Carotid Atherosclerosis Progression Study. Five variants in the gene encoding adiponectin and 7 in the gene encoding leptin were genotyped and their effects on circulating levels assessed. Both were then correlated with IMT.

RESULTS

Adiponectin levels negatively correlated with IMT (-0.079, P=0.013). There was no correlation between leptin levels or leptin:adiponectin ratio and IMT. Two variants in the ADIPOQ gene encoding adiponectin were associated with altered adiponectin levels, 1 of which (rs266729) was associated with IMT. There was also an interaction with body mass index (P=0.019) with the association being present in obese subjects (P=0.02).

CONCLUSIONS

Our results support a causal role for adiponectin in early carotid IMT and suggest it may act through interaction with obesity. In contrast, we found no evidence of a role for leptin and no evidence that leptin:adiponectin ratio is a better predictor of risk that adiponectin levels alone.

ADIPOQ SNP45 associated with lean body mass in physically active normal weight adolescent girls

Recently, two single nucleotide polymorphisms at position 45 and 276 on the adiponectin gene (ADIPOQ) have been recognized as determinants of total adiponectin levels, insulin resistance, and risk for diabetes in various obese populations.

OBJECTIVES

The aim of this study was to determine whether these two polymorphisms are indeed determinants in the development of metabolic disorders or whether they are secondary to other confounding factors.

METHODS

To do so, we have selected 170 physically active adolescent girls (mean age, 14.03 ± 1.5 years and mean body mass index, 19.98 ± 2.5 kg/m²) devoid of any metabolic diseases or confounding factors, to better attribute any findings to genotype effects. Concentration of adiponectin, insulin, and glucose were determined from blood samples with appropriate kits. Body fat parameters were evaluated with dual-energy X-ray absorptiometry, and genotype was analyzed with DNA extracted from whole blood samples followed by polymerase chain reaction and electrophoresis to separate alleles.

RESULTS

Neither single nucleotide polymorphism +45T/G nor +276G/T was related to homeostasis model assessment index or adiponectin levels; however, the presence of the G allele on site 45 favored a significant decrease in lean body mass compared with those who were T homozygous (TG:36.90/TT:41.07 kg, P < 0.05).

CONCLUSIONS

Results suggest that the reported increase in the risk of diabetes in subjects that were G allele carriers at site 45 in obese populations compared with normal-weight populations can be linked instead to a change in muscle mass or the muscle itself present in this genotype group.

Variations in Adipokine Genes AdipoQ, Lep, and LepR are Associated with Risk for Obesity-Related Metabolic Disease: The Modulatory Role of Gene-Nutrient Interactions

Obesity rates are rapidly increasing worldwide and facilitate the development of many related disease states, such as cardiovascular disease, the metabolic syndrome, type 2 diabetes mellitus, and various types of cancer. Variation in metabolically important genes can have a great impact on a population's susceptibility to becoming obese and/or developing related complications. The adipokines adiponectin and leptin, as well as the leptin receptor, are major players in the regulation of body energy homeostasis and fat storage. This paper summarizes the findings of single nucleotide polymorphisms in these three genes and their effect on obesity and metabolic disease risk. Additionally, studies of gene-nutrient interactions involving adiponectin, leptin, and the leptin receptor are highlighted to emphasize the critical role of diet in susceptible populations.

HRAS1 and LASS1 with APOE are associated with human longevity and healthy aging

The search for longevity-determining genes in human has largely neglected the operation of genetic interactions. We have identified a novel combination of common variants of three genes that has a marked association with human lifespan and healthy aging. Subjects were recruited and stratified according to their genetically inferred ethnic affiliation to account for population structure. Haplotype analysis was performed in three candidate genes, and the haplotype combinations were tested for association with exceptional longevity. An HRAS1 haplotype enhanced the effect of an APOE haplotype on exceptional survival, and a LASS1 haplotype further augmented its magnitude. These results were replicated in a second population. A profile of healthy aging was developed using a deficit accumulation index, which showed that this combination of gene variants is associated with healthy aging. The variation in LASS1 is functional, causing enhanced expression of the gene, and it contributes to healthy aging and greater survival in the tenth decade of life. Thus, rare gene variants need not be invoked to explain complex traits such as aging; instead rare congruence of common gene variants readily fulfills this role. The interaction between the three genes described here suggests new models for cellular and molecular mechanisms underlying exceptional survival and healthy aging that involve lipotoxicity.

Association of genetic variants in the adiponectin encoding gene (ADIPOQ) with type 2 diabetes in Japanese Brazilians

AIM

The objective of this study is to assess the contribution of ADIPOQ variants to type 2 diabetes in Japanese Brazilians.

METHODS

We genotyped 200 patients with diabetes mellitus (100 male and 100 female, aged 55.0 years [47.5-64.0 years]) and 200 control subjects with normal glucose tolerant (NGT) (72 male and 128 female, aged 52.0 years [43.5-64.5 years]).

RESULTS

Whereas each polymorphism studied (T45G, G276T, and A349G) was not significantly associated with type 2 diabetes mellitus, the haplotype GGA was overrepresented in our diabetic population (9.3% against 3.1% in NGT individuals, P=.0003). Also, this haplotype was associated with decreased levels of adiponectin. We also identified three mutations in exon 3: I164T, R221S, and H241P, but, owing to the low frequencies of them, associations with type 2 diabetes could not be evaluated. The subjects carrying the R221S mutation had plasma adiponectin levels lower than those without the mutation (2.10 microg/ml [1.35-2.55 microg/ml] vs. 6.68 microg/ml [3.90-11.23 microg/ml], P=.015). Similarly, the I164T mutation carriers had mean plasma adiponectin levels lower than those noncarriers (3.73 microg/ml [3.10-4.35 microg/ml] vs. 6.68 microg/ml [3.90-11.23 microg/ml]), but this difference was not significant (P=.17).

CONCLUSIONS

We identified in the ADIPOQ gene a risk haplotype for type 2 diabetes in the Japanese Brazilian population.

Concordance of two multiple analytical approaches demonstrate that interaction between BMI and ADIPOQ haplotypes is a determinant of LDL cholesterol in a general French population

Genetic and environmental factors are involved in insulin resistance (IR). IR and dyslipidemia associate with increased risk of cardiovascular diseases. Plasma low-density lipoprotein cholesterol (LDL-C) level is a marker of cardiovascular risk. In a Caucasian general population we aimed at determining the multifactorial components of LDL-C levels using 10 genes and 3 phenotypes. In the PPARG, UCP3, ADIPOQ, TNF, LIPC, CARTPT, PCSK9, SCAP, SCARB1 and ENPP1 genes known to be associated with IR or dyslipidemia we genotyped 19 single nucleotide polymorphisms (SNPs) in 846 subjects. When several SNPs were genotyped for a given gene we constructed haplotypes. Including genetic and environmental variables (gender, body mass index (BMI) and adiponectin level) we used (1) the multifactor dimensionality reduction method to explain clusters of high and low LDL-C, and (2) the restricted partition method to explain LDL-C levels. Both methods showed that BMI and haplotypes at the ADIPOQ adiponectin encoding gene but not adiponectin level itself, were discriminant regarding to LDL-C. Subjects bearing an at-risk combination of BMI and ADIPOQ genotypes were prone to have a higher LDL-C (OR=3.13, 95% CI=2.20-4.46, P<0.0001). Our results suggest that in interaction with BMI, ADIPOQ haplotypes capture genetic variation(s) from neighboring gene(s) that would modulate LDL-C level.

Adiponectin gene polymorphisms in obese Greek youth

We investigated single nucleotide polymorphisms 45T --> G and 276G --> T of the adiponectin gene in 48 obese Greek children and adolescents (3.58-16.25 years old) and examined their association with adiponectin levels and insulin resistance (IR), estimated with HOMA-IR, AUC(insulin) and WBISI. The polymorphisms were: 45T/G in 13/48 (27%) and 45G/G in 2 (4%) individuals; 276G/T in 21/41 (51%) and 276T/T in 3 (8%) individuals. Adiponectin in carriers of one or two G-alleles at position 45 was comparable to 45T/T (10.11 +/- 6.19 vs 8.03 +/- 4.96 microg/ml). Adiponectin in carriers of one or two T-alleles at position 276 was comparable to 276G/G (9.73 +/- 5.19 vs 7.77 +/- 5.65 microg/ml). SNP 45T --> G was not associated with IR. SNP276G --> T was associated with decreased risk for IR (OR = 3.05, 95% CI = 1.2384-11.13). In conclusion, SNPs 45T --> G and 276G --> T are common in obese young Greeks. SNP276G --> T might be protective against 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.

APM1 gene variants -11377C/G and 4545G/C are associated respectively with obesity and with non-obesity in Chinese type 2 diabetes

In order to explore the different genetic backgrounds of non-obese and obese type 2 diabetes, we tried to genotype six SNPs (-11391G/A, -11377C/G, -10068G/A, G54V, Y111H and 4545G/C) in the adipose most abundant gene transcript-1 (APM1) gene in 338 type 2 diabetes (T2D) patients and 460 non-diabetic subjects by PCR-RFLP. Among these mutations, the 4545G/C mutation (rs1063539) contributed to the genetic risk of T2D in the non-obese group (OR=2.34, 95%CI: 1.31-4.21, P=0.004), and 57% of the risk is related to this polymorphism. On the contrary, -11377C/G (rs266729) was associated with type 2 diabetes in the obese group only (OR=2.45, 95%CI: 1.13-5.31, P=0.02), and 59% risk of diabesity could be attributed to that. All the associations above were adjusted for age and gender in unconditional logistic regression. Besides, the -11377G/4545C haplotype was merely related to obese diabetes (OR=2.12, 95%CI: 1.08-4.14, P=0.03). In addition, the obese diabetic group had significantly higher levels of triglyceride and insulin, better beta-cell function but lower glucose levels than the non-obese group (all P values <0.01). This study suggests that the genetic susceptibility is different between type 2 diabetes with and without obesity in Chinese Han population.

Adiponectin and functional adiponectin receptor 1 are expressed by airway epithelial cells in chronic obstructive pulmonary disease

We screened bronchoalveolar lavage (BAL) fluids from COPD-E (chronic obstructive pulmonary disease-Emphysema) and control subjects using a 120 Ab cytokine array and demonstrated that adiponectin was highly expressed in BAL in COPD-E. An adiponectin ELISA confirmed that adiponectin was highly expressed in BAL in COPD-E compared with smokers and healthy control subjects. Immunohistochemistry studies of lung sections from subjects with COPD-E demonstrated that airway epithelial cells expressed significant levels of adiponectin and adiponectin receptor (AdipoR) 1 but not AdipoR2. In vitro studies with purified populations of human lung A549 epithelial cells demonstrated that they expressed both adiponectin and AdipoR1 (but not AdipoR2) as assessed by RT-PCR, Western blot, and immunohistochemistry. Lung A549 epithelial AdipoR1were functional as incubation with adiponectin induced release of IL-8, which was inhibited by small interfering RNA to AdipoR1. Using a mouse model of COPD, tobacco smoke exposure induced both evidence of COPD as well as increased levels of adiponectin in BAL fluid and increased adiponectin expression by airway epithelial cells. As adiponectin expression in adipocytes is dependent upon NF-kappaB we determined levels of adiponectin in tobacco smoke exposed CC10-Cre(tg)/Ikkbeta(Delta/Delta) mice (deficient in the ability to activate NF-kappaB in airway epithelium). These studies demonstrated that CC10-Cre(tg)/Ikkbeta(Delta/Delta) and wild-type mice had similar levels of BAL adiponectin and airway epithelial adiponectin immunostaining. Overall, these studies demonstrate the novel observation that adiponectin and functional AdipoR1are expressed by lung epithelial cells, suggesting a potential autocrine and/or paracrine pathway for adiponectin to activate epithelial cells in COPD-E.

Association of adiponectin gene polymorphisms with type 2 diabetes in an African American population enriched for nephropathy

OBJECTIVE

Polymorphisms in the adiponectin gene (ADIPOQ) have been associated with type 2 diabetes and diabetic nephropathy in type 1 diabetes, in mostly European-derived populations.

RESEARCH DESIGN AND METHODS

A comprehensive association analysis of 24 single-nucleotide polymorphisms (SNPs) in the adiponectin gene was performed for type 2 diabetes and diabetic nephropathy in African Americans.

RESULTS

The minor allele (A) in a single SNP in intron 1 (rs182052) was associated with diabetic nephropathy (P = 0.0015, odds ratio [OR] 1.37, CI 1.13-1.67, dominant model) in an African American sample of 851 case subjects with diabetic nephropathy and 871 nondiabetic control subjects in analyses incorporating adjustment for varying levels of racial admixture. This association remained significant after adjustment of the data for BMI, age, and sex (P = 0.0013-0.0004). We further tested this SNP for association with longstanding type 2 diabetes without nephropathy (n = 317), and evidence of association was also significant (P = 0.0054, OR 1.46, CI 1.12-1.91, dominant model) when compared with the same set of 871 nondiabetic control subjects. Combining the type 2 diabetes and diabetic nephropathy samples into a single group of case subjects (n = 1,168) resulted in the most significant evidence of association (P = 0.0003, OR 1.40, CI 1.17-1.67, dominant model). Association tests between age at onset of type 2 diabetes and the rs182052 genotypes also revealed significant association between the presence of the minor allele (A/A or A/G) and earlier onset of type 2 diabetes.

CONCLUSIONS

The SNP rs182052 in intron 1 of the adiponectin gene is associated with type 2 diabetes in African Americans.

The cost-effectiveness of insulin glargine vs. neutral protamine Hagedorn insulin in type 2 diabetes: a focus on health economics

Diabetes mellitus is a major public health problem, in particular because of long-term complications affecting essential organs, such as the eyes and kidneys, which can lead to a reduction in life expectancy and high healthcare costs. The number of individuals with diabetes mellitus is projected to rise worldwide from 171 million people in 2000 to 366 million people in 2030. With the number of patients with diabetes continually growing, the burden of pressure on worldwide health systems is huge. Accordingly, regulatory and marketing approvals of new medicines are beginning to incorporate economic evaluation techniques to determine their cost-effectiveness. Overall, the studies included in this review show that the initiation of insulin glargine is cost-effective and is expected to lead to substantial improvements in both life years (LYs) and quality-adjusted LYs compared with neutral protamine Hagedorn insulin.

Adiponectin gene ADIPOQ SNP associations with serum adiponectin in two female populations and effects of SNPs on promoter activity

Adiponectin is an insulin sensitiser in muscle and liver, and low serum levels characterise obesity and insulin resistance. Eight tagging single nucleotide polymorphisms (tSNPs) in the ADIPOQ gene and promoter were selected, and association with serum adiponectin was tested, in two independent samples of Caucasian women: the Chingford Study (n = 808, mean age 62.8 +/- 5.9 years) and Twins UK (n = 2,718, mean age 47.4 +/- 12.6 years). In the Chingford cohort, -11391 G/A, -10066 G/A (rs182052), -7734 C/A (rs16861209), +276 G/T (rs1501299) and +3228 C/T (rs1063537) were significantly associated with fasting serum adiponectin (Ps = 1.00 x 10(-4) to 1.40 x 10(-2)). Associations with all except +3228 C/T were replicated in the Twins UK cohort (Ps = 3.19 x 10(-9) to 6.00 x 10(-3)). In Chingford subjects, the 12 most common 8-SNP haplotypes (frequency 1.90%) explained 2.85% (p = 5.00 x 10(-2)) and in Twins UK subjects, the four most common 5-SNP haplotypes (frequency > 5.00%) explained 1.66% of the variance (p = 5.83 x 10(-7)). To investigate effects of -11391 G/A (rs17300539) and -11377 C/G (rs266729) on promoter activity, 1.2 kb of the ADIPOQ promoter region was cloned in a luciferase reporter plasmid, and the four haplotypes were transfected in differentiated 3T3-L1 adipocytes. No significant allelic effects on promoter activity were found.

Genetic polymorphisms of adiponectin and tumor necrosis factor-alpha and nonalcoholic fatty liver disease in Chinese people

BACKGROUND AND AIM

Hypoadiponectinemia and high tumor necrosis factor-alpha (TNF-alpha) levels are associated with the development of nonalcoholic fatty liver disease (NAFLD). This study aimed to investigate the genetic polymorphisms of adiponectin and TNF-alpha in Chinese NAFLD patients and their association with disease severity.

METHODS

Seventy-nine patients with histology-proven NAFLD (61 with simple steatosis and 18 with stage 2-4 fibrosis) and 40 controls were tested for the nucleotide polymorphisms at adiponectin -11 391, -11 377, +45, and +276 and TNF-alpha promoters -863, -308, and -238.

RESULTS

There was no significant deviation in the adiponectin and TNF-alpha gene polymorphisms between NAFLD patients and controls, or between patients with simple steatosis and those with stage 2-4 fibrosis. NAFLD patients with -11377G and +45G at the adiponectin gene were more likely to have hypertriglyceridemia. On multivariate analysis, older age, higher body mass index, and higher fasting glucose were independent factors associated with stage 2-4 fibrosis in NAFLD patients.

CONCLUSIONS

Adiponectin and TNF-alpha gene polymorphisms were not shown to be associated with NAFLD or significant fibrosis in Chinese people. The adiponectin -11377G and +45G alleles were associated with hypertriglyceridemia in NAFLD patients. Since the current study is not adequately powered to detect smaller differences in allele frequencies, larger-sized studies in different ethnic groups are required.

A novel association of a polymorphism in the first intron of adiponectin gene with type 2 diabetes, obesity and hypoadiponectinemia in Asian Indians

Adiponectin is an adipose tissue specific protein that is decreased in subjects with obesity and type 2 diabetes. The objective of the present study was to examine whether variants in the regulatory regions of the adiponectin gene contribute to type 2 diabetes in Asian Indians. The study comprised of 2,000 normal glucose tolerant (NGT) and 2,000 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. We identified two proximal promoter SNPs (-11377C-->G and -11282T-->C), one intronic SNP (+10211T-->G) and one exonic SNP (+45T-->G) by SSCP and direct sequencing in a pilot study (n = 500). The +10211T-->G SNP alone was genotyped using PCR-RFLP in 4,000 study subjects. Logistic regression analysis revealed that subjects with TG genotype of +10211T-->G had significantly higher risk for diabetes compared to TT genotype [Odds ratio 1.28; 95% Confidence Interval (CI) 1.07-1.54; P = 0.008]. However, no association with diabetes was observed with GG genotype (P = 0.22). Stratification of the study subjects based on BMI showed that the odds ratio for obesity for the TG genotype was 1.53 (95%CI 1.3-1.8; P < 10(-7)) and that for GG genotype, 2.10 (95% CI 1.3-3.3; P = 0.002). Among NGT subjects, the mean serum adiponectin levels were significantly lower among the GG (P = 0.007) and TG (P = 0.001) genotypes compared to TT genotype. Among Asian Indians there is an association of +10211T-->G polymorphism in the first intron of the adiponectin gene with type 2 diabetes, obesity and hypoadiponectinemia.

Associations between glucose tolerance, insulin sensitivity and insulin secretion phenotypes and polymorphisms in adiponectin and adiponectin receptor genes in the Quebec Family Study

AIMS

Studies suggest that adiponectin (APM1) and its receptors 1 and 2 (AdipoR1 and AdipoR2) play an important role in the development of insulin resistance (IR). Our objective was to examine associations between APM1 (+45T>G, +276G>T and -3971A>G), AdipoR1 (-100G>T and -3882T>C) and AdipoR2 (-35361A>G and -1352G>A) genes single-nucleotide polymorphisms (SNPs) and adiponectin plasma levels, indicators of glucose tolerance, insulin sensitivity (IS) and insulin secretion.

METHODS

Six hundred and twenty-two non-diabetic subjects from the Quebec Family Study (QFS) underwent a 75-g oral glucose tolerance test (OGTT), with measurement of fasting adiponectin, glucose, insulin and C-peptide levels. Indices of glucose tolerance, IS and insulin secretion were derived from fasting and OGTT measurements.

RESULTS

Significant evidence of association was found between indices of IS and APM1 and AdipoR1 SNPs. The APM1 -3971G/G homozygotes exhibited a reduced area under the curve of insulin during the OGTT (P = 0.007) and higher Cederholm index (P = 0.01) compared to the A/A homozygotes. The APM1+45T>G variant was also associated with fasting (P = 0.002) and 2-h (P = 0.007) glucose values as well as with higher Cederholm index (P = 0.04) and disposition index (P = 0.02). Finally, the AdipoR1-3882T>C SNP was associated with fasting glucose (P = 0.03), the homeostasis model assessment for insulin resistance (P = 0.04) and an index of insulin secretion (P30/G30, P = 0.02). No evidence of association was found with plasma adiponectin levels.

CONCLUSIONS

These results provide evidence for an influence of common SNPs in the APM1 and AdipoR1 genes on different phenotypes of glucose and insulin metabolism associated with increased risk of type 2 diabetes.

Adiponectin levels are reduced, independent of polymorphisms in the adiponectin gene, after supplementation with alpha-linolenic acid among healthy adults

Our first aim was to determine whether an isocaloric intervention using alpha-linolenic acid (ALA) in the form of flaxseed oil would alter adiponectin levels among overweight, otherwise healthy, males and females, and our second aim was to test for any potential modification of this intervention by 2 single nucleotide polymorphisms (276 and 45) in the adiponectin gene. Subjects included healthy adult males and females (approximately 81% female; average age, 38 years) with increased waist circumference (mean, 99 cm) and body mass index (mean, 30 kg/m(2)) who were free of chronic disease, not taking medications, and sedentary. Subjects met weekly with a registered dietician for 8 weeks. The control subjects (n = 27) were instructed not to alter their habitual diet and the ALA group (n = 30) was instructed to follow an enriched ALA diet by using flaxseed oil capsules (increasing ALA to 5% of total energy intake) and to lower their dietary fat consumption by a commensurate amount. Diets were analyzed using the Food Intake and Analysis System (v. 3.0, University of Texas School of Public Health, 1998). Fasting blood samples were obtained before and after the 8-week intervention. We found significant decreases (P = .02) in adiponectin (10.12 microg/mL pre, 9.23 microg/mL post) in the ALA group as compared with the control group (7.93 microg/mL pre, 8.10 microg/mL post) after the intervention. We also saw a decline in adiponectin in all genotype groups with the greatest decline among those carrying the rare T allele of single nucleotide polymorphism 276. There were no significant changes in fasting insulin, glucose, or quantitative insulin sensitivity check index values as a result of this intervention. In conclusion, this study suggests that supplementing with ALA for 8 weeks may lower adiponectin levels among healthy individuals, and this effect appears to be independent of polymorphisms in the adiponectin gene. Although the change in adiponectin in response to the omega-3 fatty acids was not accompanied by any change in glucose, insulin, or quantitative insulin sensitivity check index, long-term implications of such a decrease should be considered in future studies.

Associations of adiponectin with body fat distribution and insulin sensitivity in nondiabetic Hispanics and African-Americans

CONTEXT

Hypoadiponectinemia has emerged as an independent risk factor for type 2 diabetes and cardiovascular disease. Although associations of adiponectin with central obesity and insulin resistance have been reported, very little data are available from studies using detailed measures of insulin sensitivity (S(I)) and/or body fat distribution in ethnic groups at high risk for metabolic disease.

OBJECTIVE

The aim of the study was to identify the correlates of adiponectin in 1636 nondiabetic Hispanics and African-Americans.

DESIGN

A cross-sectional analysis of participants in the Insulin Resistance Atherosclerosis Family Study was conducted. S(I) was determined from frequently sampled iv glucose tolerance tests with minimal model analysis. Subcutaneous and visceral adipose tissues (SAT, VAT, respectively) were determined with computed tomography. Triglyceride, high-density lipoprotein, C-reactive protein, and adiponectin were measured in fasting samples. Generalized estimating equation (GEE) models were used to identify factors associated with adiponectin concentration.

SETTING

A multicenter study using a family-based design was conducted.

PARTICIPANTS

A total of 1636 nondiabetic Hispanic and African-American subjects participated.

MAIN OUTCOME MEASURES

Circulating adiponectin concentration was measured.

RESULTS

Age, female gender, high-density lipoprotein, SAT, and S(I) were positive independent correlates of adiponectin, whereas glucose, CRP, and VAT were negative independent correlates (all P < 0.05). Ethnicity was not an independent correlate of adiponectin in this model (P = 0.27); however, an ethnicity by VAT interaction term was retained, indicating a stronger negative association of VAT with adiponectin in African-Americans compared with Hispanics.

CONCLUSION

Directly measured S(I), VAT, and SAT were independently correlated with adiponectin in Hispanic and African-American subjects. The inverse association of VAT with adiponectin was stronger in African-Americans compared with Hispanics, a finding that suggests possible ethnic differences in the effects of visceral obesity.

Common adiponectin gene variants show different effects on risk of cardiovascular disease and type 2 diabetes in European subjects

Alterations in the secretion of adipokines may explain the link between obesity, type 2 diabetes (T2DM) and coronary artery disease (CAD). These conditions have been associated with variation in the adiponectin gene, although evidence for this relationship has been variable, with differences found even in similar samples. This study aims to clarify these inconsistencies by determining the impact of identified adiponectin gene (ADIPOQ) variants (-11391G>A,-1377C>G[promoter] and +45T>G[exon 2] and +276G>T[intron 2]) on the prospective risk of CAD and T2DM in healthy men, and on adverse metabolic markers, in myocardial infarct survivors and controls from different parts of Europe. The hazard ratio for cardiovascular disease varied across the -11391GG/GA/AA(p = 0.03) and -11371CC/CG/GG(p = 0.05) genotypes only. In contrast, only the +45T>G variant (3.80[1.76-8.24]) was associated with T2DM, while two haplotypes GCTT/GCGG (p < 0.05) and +276G>T(p = 0.01) increased risk in interaction with obesity. The variants were associated with a number of biomarkers in Southern but not Northern Europe (p = 0.01), despite no significant differences in allele or haplotype frequencies (p > 0.44). A risk haplotype could not be identified in either sample. Adiponectin gene variants are hence currently poor markers for the development of T2DM and CAD. Their influence on risk depends significantly on interactions that are not currently understood with either genetic variation elsewhere or the environment of the sample studied.

Adiponectin and adiponectin receptors in insulin resistance, diabetes, and the metabolic syndrome

Adiponectin is an adipokine that is specifically and abundantly expressed in adipose tissue and directly sensitizes the body to insulin. Hypoadiponectinemia, caused by interactions of genetic factors such as SNPs in the Adiponectin gene and environmental factors causing obesity, appears to play an important causal role in insulin resistance, type 2 diabetes, and the metabolic syndrome, which are linked to obesity. The adiponectin receptors, AdipoR1 and AdipoR2, which mediate the antidiabetic metabolic actions of adiponectin, have been cloned and are downregulated in obesity-linked insulin resistance. Upregulation of adiponectin is a partial cause of the insulin-sensitizing and antidiabetic actions of thiazolidinediones. Therefore, adiponectin and adiponectin receptors represent potential versatile therapeutic targets to combat obesity-linked diseases characterized by insulin resistance. This Review describes the pathophysiology of adiponectin and adiponectin receptors in insulin resistance, diabetes, and the metabolic syndrome.

Hypoadiponectinemia is associated with progression toward type 2 diabetes and genetic variation in the ADIPOQ gene promoter

OBJECTIVE

Adiponectin encoded by the ADIPOQ gene modulates insulin sensitivity and glucose homeostasis. The aim of the current study was to investigate whether ADIPOQ gene variants in the promoter region predict adiponectin levels and type 2 diabetes progression.

RESEARCH DESIGN AND METHODS

A total of 550 subjects with increased risk of type 2 diabetes were investigated; they underwent a 75-g oral glucose tolerance test, repeated after 3 years. Adiponectin levels were analyzed, and two ADIPOQ promoter variant single nucleotide polymorphisms, -11391G>A and -11377C>G, were genotyped.

RESULTS

Tertiles of the adjusted adiponectin levels were associated with single nucleotide polymorphism -11391G>A and -11377C>G haplotypes (P < 0.0001). Carriers of the intermediate/high-level haplotype combination showed a bisected diabetes risk at the 3-year follow-up and were characterized by a "regression" of glucose tolerance. Evolution of disease status correlates with preexisting low adiponectin levels at inclusion rather than with variation in adiponectin levels.

CONCLUSIONS

We present data that gene variants in the ADIPOQ promoter region are associated with variations in adiponectin levels and thus with future type 2 diabetes and disease progression.