SNP276G>T polymorphism in the adiponectin gene is associated with metabolic syndrome in patients with Type II diabetes mellitus in Korea

Serum adiponectin and cortisol levels are not affected by studied ADIPOQ gene variants: Tehran lipid and glucose study

BACKGROUND

Obesity is a major public health concern in developed and even developing countries worldwide. Adiponectin is a protein secreted by adipose tissue that modulates many metabolic processes and plays a vital role in obesity. This study aimed to determine the association of four variants of the ADIPOQ gene with serum adiponectin, cortisol levels and obesity status.

METHODS

This case-control study was performed on 164 obese individuals compared by 156 control from the Tehran Lipid and Glucose Study (TLGS). Standard procedures obtained anthropometric measures and metabolic parameters. Cortisol and adiponectin levels were measured by ELISA method. rs1501299, rs266729, rs17300539, and rs17366743 on the ADIPOQ gene were genotyped using the PCR-RFLP. The correlation between adiponectin gene SNPs and obesity were calculated by Additive, dominant, and recessive genetic models. Pearson's or Spearman's found correlations between adiponectin levels and metabolic and anthropometric variables. Data were analyzed using SPSS software Version 20.

RESULTS

Adiponectin and cortisol levels were significantly lower in obese subjects compared to the control group (p < 0.05). There was a significant negative correlation between serum adiponectin level and BMI, waist circumference (WC), waist-hip ratio, hip circumference (HC), Fasting blood sugar (FBS) Triglyceride (TG), Total cholesterol (TC), Systolic blood pressure (SBP), Diastolic blood pressure (DBP) (r = - 0.147, r = - 0.324, r = 0.371, r = - 0.179, r = - 0.299, r = - 0.277, r = - 0.041, r = - 0.134, and r = - 0.149, respectively). A positive correlation was found between adiponectin and high-density lipoprotein cholesterol (HDL-C) (r = 0.29), but no significant correlations were found between adiponectin and Low-density lipoprotein cholesterol(LDL-C) and cortisol. ADIPOQ variant rs1501299 was significantly associated with cortisol levels in subjects with BMI ≥ 25 (P-value =0.039).

CONCLUSIONS

Adiponectin and cortisol levels were associated with obesity. No ADIPOQ gene variants and haplotypes were associated with cortisol, Adiponectin, and obesity.

Association of polymorphisms in leptin and adiponectin genes with long-term outcomes in renal transplant recipients

The effect of polymorphims in leptin and adiponectin genes on long-term outcomes of renal transplantation is unknown. In 349 renal transplant recipients (RTR), we aimed to determine associations between five SNPs in the leptin receptor (LEPR) and adiponectin (ADIPOQ) genes and these outcomes. Follow-up time ranged from 2 to 25 years (mean 10.29 ± 5.16 years). Two SNPs showed associations with long-term outcomes and their statistical significance greatly increased after 39 RTR with a history of cardiovascular events prior to transplantation were removed from the analysis. Adjusted odds ratios (OR) for LEPR rs1805094 and ADIPOQ rs1501299 and risk of graft loss were 0.35 (0.16-0.74) p = 0.006 and 2.37 (1.28-4.37) p = 0.006, respectively. The assessment of risk for global mortality revealed OR values of 0.20 (0.06-0.62), p = 0.005, and 2.43 (1.08-5.44), p = 0.031 for LEPR rs1805094 and ADIPOQ rs1501299, respectively. Our results show that polymorphism in genes involved in leptin and adiponectin function modify long-term outcomes in renal transplantation.

Association of adiponectin and resistin gene polymorphisms in South Indian women with polycystic ovary syndrome

OBJECTIVES

To investigate whether genetic polymorphisms in the resistin and adiponectin genes cause a predisposition towards polycystic ovary syndrome (PCOS) in a South Indian women population.

STUDY DESIGN

This case controlled study included samples from 484 study subjects (282 diagnosed with PCOS and 200 normal controls). The clinical and biochemical parameters of the samples assayed included BMI, LH, FSH, testosterone, fasting glucose, adiponectin and resistin levels. Three single nucleotide polymorphisms of the resistin (RETN) gene 420(C→G) (rs1862513), 299(G→A) (rs3745367), and 62(G→A) (rs3745368), and two single nucleotide polymorphisms of the adiponectin (ADPIOQ) gene 45(T→G) (rs2241766), and 276(G→T) (rs1501299), were analyzed using a PCR-RFLP method. Statistical analysis was carried out to determine the association of the genotypic and allelic variations with the syndrome and also analyze the influence of genotypic variations on adipokine levels.

RESULTS

Serum levels of testosterone, LH, fasting glucose and resistin were found to be significantly increased in the PCOS patients when compared to controls, while adiponectin was found to be significantly lower (P<0.05). BMI was found to positively correlate with resistin levels and negatively correlate with adiponectin levels. A positive association was found between the RETN promoter 420 (C→G) SNP and the intron 2 299 (G→A) variant of the resistin gene, while no association was found between the ADPIOQ gene polymorphisms and PCOS. The 'GG' variant of the adiponectin 45 (T→G) variant showed a near-significant tendency towards a decreased concentration of adiponectin in PCOS patients.

CONCLUSIONS

Polymorphisms of the resistin gene could be assigned to play a role in increasing the risk of PCOS. However, the adiponectin gene does not seem to play a major role in PCOS susceptibility in a South Indian population. Serum adiponectin and resistin levels were more dependent on BMI rather than the presentation of PCOS. Obesity plays a major role in aggravating the hormonal disturbances found associated with PCOS.

Association of two Common Single Nucleotide Polymorphisms (+45T/G and +276G/T) of ADIPOQ Gene with Coronary Artery Disease in Type 2 Diabetic Patients

Background:

Adiponectin, an adipocyte-secreted hormone, is known to have anti-atherogenic, anti-inflammatory, and anti-diabetic properties. In the present study, the association between two common single nucleotide polymorphisms (SNPs) (+45T/G and +276G/T) of ADIOPQ gene and coronary artery disease (CAD) was assessed in the subjects with type 2 diabetes (T2DM).

Methods:

Genotypes of two SNPs were determined by polymerase chain reaction-restriction fragment length polymorphism in 200 subjects with T2DM (100 subjects with CAD and 100 without CAD).

Results:

The frequency of TT genotype of +276G/T was significantly elevated in CAD compared to controls (χ²=7.967, P=0.019). A similar difference was found in the allele frequency of +276G/T between two groups (χ²=3.895, P=0.048). The increased risk of CAD was associated with +276 TT genotype when compared to reference GG genotype (OR=5.158; 95% CI=1.016-26.182, P=0.048). However, no similar difference was found in genotype and allele frequencies of SNP +45T/G between two groups. There was a CAD protective haplotype combination of +276 wild-type and +45 mutant-type allele (276G-45G) (OR=0.37, 95% CI=0.16-0.86, P=0.022) in the subject population.

Conclusion:

Our findings indicated that T allele of SNP +276G/T is more associated with the increased risk of CAD in subjects with T2DM. Also, a haplotype combination of +45G/+276G of these two SNPs has a protective effect on the risk of CAD.

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.

Association of the adiponectin gene rs1501299 G>T variant, serum adiponectin levels, and the risk of coronary artery disease in a Chinese population

BACKGROUND

The present study aimed to investigate whether the single nucleotide polymorphism (SNP) 276G>T (rs1501299) of the adiponectin (ADIPOQ) gene was associated with the risk of coronary artery disease (CAD) and serum adiponectin levels in a Chinese population.

METHODS

The rs1501299 polymorphism of the ADIPOQ gene was genotyped in 438 subjects with angiographically diagnosed CAD and 443 controls. Levels of serum adiponectin were determined in 152 CAD subjects and 155 controls.

RESULTS

The CAD subjects had GT and TT genotypes more frequently, and had GG genotype less frequently than the controls. The OR increased and was significant after adjustment for known CAD risk factors. Significant difference was also observed with T allele being more frequent among the CAD subjects. The T allele at the rs1501299 polymorphism was associated with a higher risk of CAD. The mean adiponectin levels of CAD patients were lower than control subjects. No significant correlation was seen of different genotypes with serum adiponectin levels.

CONCLUSIONS

The adiponectin rs1501299 G>T variant was positively related with an increased risk of CAD, and the CAD patients had lower adiponectin levels which were not affected by the different genotypes of rs1501299 in the present study.

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 variants and the metabolic syndrome: a systematic review

Several candidate gene studies on the metabolic syndrome (MetS) have been conducted. However, for most single nucleotide polymorphisms (SNPs) no systematic review on their association with MetS exists. A systematic electronic literature search was conducted until the 2nd of June 2010, using HuGE Navigator. English language articles were selected. Only genes of which at least one SNP-MetS association was studied in an accumulative total population ≥ 4000 subjects were included. Meta-analyses were conducted on SNPs with three or more studies available in a generally healthy population. In total 88 studies on 25 genes were reviewed. Additionally, for nine SNPs in seven genes (GNB3, PPARG, TCF7L2, APOA5, APOC3, APOE, CETP) a meta-analysis was conducted. The minor allele of rs9939609 (FTO), rs7903146 (TCF7L2), C56G (APOA5), T1131C (APOA5), C482T (APOC3), C455T (APOC3) and 174G>C (IL6) were more prevalent in subjects with MetS, whereas the minor allele of Taq-1B (CETP) was less prevalent in subjects with the MetS. After having systematically reviewed the most studied SNP-MetS associations, we found evidence for an association with the MetS for eight SNPs, mostly located in genes involved in lipid metabolism.

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.