Distribution and genotype frequency of adiponectin (+45 T/G) and adiponectin receptor2 (+795 G/A) single nucleotide polymorphisms in Iranian population

ADIPOQ + 45T≥G Polymorphism, Food Ingestion, and Metabolic Syndrome in Elderly Persons

INTRODUCTION

The current nutritional transition process contributes further to accelerate the onset of metabolic disorders, as do a number of environmental factors that lead to the diagnosis of chronic diseases, as a diet of low nutritional value, is possibly related to the incidence of metabolic syndrome. In addition to these factors, metabolic syndrome may also be related to genetic factors, the ADIPOQ + 45T> G polymorphism has been associated with serum adiponectin levels, insulin sensitivity, and obesity, which affects adiponectin levels act as protective factor for cardiovascular disease. In this way, the present study aimed to analyze the possible association between the ADIPOQ + 45T> G gene polymorphism, usual diet and metabolic syndrome in the elderly.

METHODS

We evaluated inflammatory and biochemical markers compared with older age groups (age 60 years) with and without metabolic syndrome. In addition to the anthropometric measurements of weight, height and waist circumference, the ADIPOQ + 45T> G gene polymorphism was determined by PCR- RFLP, and food consumption was investigated using a food frequency questionnaire.

RESULTS

The study included 111 elderly individuals. Our main results show that there was a significant relationship between the habitual consumption of milk for the group that had metabolic syndrome (p < 0.05). HDL-c levels, glucose, triglycerides, diastolic blood pressure and weight, height and waist circumference had to be altered in patients with metabolic syndrome. There was an association between habitual dietary intake of white meat with haplotypes TG and GG.

CONCLUSION

We conclude that the relationship between the habitual consumption of certain food groups and ADIPOQ indicates the need for further studies to develop a better understanding of this relationship; however, there was no association between the ADIPOQ + 45T> G gene polymorphism and metabolic syndrome in the group of elderly studied.

Prevalence Rates of ADIPOQ Polymorphisms in Indian Population and a Comparison with Other Populations

INTRODUCTION

The adiponectin gene, ADIPOQ, encodes an adipocytokine, known as adiponectin hormone. This hormone is known to be associated with insulin sensitization, fat metabolism, immunity, and inflammatory response. Polymorphisms in ADIPOQ gene lower the adiponectin levels, increasing the risk for diabetes and cardiovascular diseases.

AIMS

The study aimed to calculate the prevalence rates of ADIPOQ polymorphisms in Indian population and to compare those prevalence rates with that of other populations.

SUBJECTS AND METHODS

Microarray-based genotypic data of 14 ADIPOQ polymorphisms from 703 individuals of Indian origin were used.

STATISTICAL ANALYSIS USED

Frequency estimation, identity-by-descent, Hardy-Weinberg equilibrium, Chi-square test of significance were used for statistical analysis.

RESULTS

Allelic and genotypic frequencies of ADIPOQ polymorphisms, Chi-square tests of significance for allelic and genotypic frequencies across various populations.

CONCLUSIONS

East Asians are very different from Indians in terms of allelic and genotypic frequencies of ADIPOQ polymorphisms. Europeans have similar genotypic and allelic patterns with Indians. Admixture Americans and Africans also showed significant differences with polymorphisms of the Indian population.

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.

The association of circulating adiponectin and + 45 T/G polymorphism of adiponectin gene with gestational diabetes mellitus in Iranian population

Background

Adiponectin is an adipokine with insulin-sensitizing effects. We investigated the relationship between the single nucleotide polymorphism (SNP) +45 T > G ( rs 2241766 ;Gly15Gly) in the adiponectin gene, serum adiponectin levels, insulin resistance and risk of gestational diabetes (GDM) in Iranian population.

Methods

65 GDM patients and 70 healthy pregnant women were enrolled in this study. Genotyping for SNP +45 T > G in the adiponectin gene ( rs 2241766 ) was performed by the polymerase chain reaction-restriction fragment length polymorphism method. The level of fasting serum adiponectin, insulin, glucose, and lipid levels were measured. Insulin resistance was estimated using homeostasis model of assessment for insulin resistance (HOMA-IR).

Results

The G allele and TG/GG genotype of rs 2241766 were more frequent than the T allele and TT genotype in GDM patients compared to the controls (p < 0.05). Multiple logistic regression analysis revealed that the risk of GDM was significantly higher in subjects with the TG/GG genotype to those with TT genotype [odds ratio = 2.38, 95% CI 1.09-5.22, p = 0.030]. No significant association was observed between genotypes of rs 2241766 and circulating concentrations of adiponectin. Multiple regression analysis showed that serum adiponectin levels was negatively associated with HOMA-IR in GDM patients (β = −0.385, p <0.01).

Conclusion

The findings demonstrated that TG/GG genotype of rs 2241766 was an independent risk factor of GDM in our population. Furthermore, circulating adiponectin level was negatively correlated with insulin resistance in GDM patients.

SNPs in the adiponectin receptor 2 gene and their associations with chicken performance traits

The adiponectin receptor 2 (ADIPOR2) is a receptor for both globular and full-length adiponectin. In the current study, two genetic variations in ADIPOR2 gene were identified in an F2 resource population of Gushi chicken and Anka broiler. Association analysis between the two SNPs and chicken performance traits were determined using the linear mixed model. The data revealed that the g.34490C > T mutation in intron 3 was significantly associated with liver weight and globulin, the g.35363T > C polymorphism in exon 5 was significantly associated with body weights at 6, 10, and 12 weeks of age. Both polymorphisms have no significant effects on serum glucose and fat-related traits. The g.34490C > T mutation might play an important role in regulating liver weight. The g.35363T > C polymorphism does contribute in a significant manner to growth traits at the medium and later development stage but it is uncertain whether it could be a molecular marker for liver disease.

Adiponectin gene polymorphisms may not be associated with idiopathic premature ovarian failure

Premature ovarian failure (POF) is a syndrome characterized by loss of ovarian function before the age of 40 years. Adiponectin, a protein secreted by adipose tissue, exerts beneficial effects on glucose and lipid metabolism. Transcription of adiponectin and its receptor gene is correlated with follicular development. POF, as a type of pathological ovarian aging, is associated with an increase in fat mass and body weight, in which adiponectin may be involved. The present study aimed to investigate the relationship between adiponectin gene polymorphisms and idiopathic POF in Chinese women. We examined DNA samples of the variant SmaI (rs2241766) and BsmI (rs1501299) loci of the adiponectin gene in 120 POF patients and 104 controls. Polymerase chain reaction and restriction fragment length polymorphism were used to assess these genotype variants. Our results showed that the genotype distributions of the SmaI and BsmI polymorphisms did not significantly differ between the patients with idiopathic POF and the controls. Moreover, no significant difference was found between the controls and POF patients in the haplotype analysis. This suggests that the SmaI and BsmI polymorphisms of adiponectin gene might not be responsible for idiopathic POF, at least, in the Chinese population. More researches are required to determine whether these findings can be extrapolated to other populations.

Associations of the TNF-alpha -308 G/A, IL6 -174 G/C and AdipoQ 45 T/G polymorphisms with inflammatory and metabolic responses to lifestyle intervention in Brazilians at high cardiometabolic risk

BACKGROUND

Cytokines secreted by the adipose tissue influence inflammation and insulin sensitivity, and lead to metabolic disturbances. How certain single-nucleotide polymorphisms (SNPs) interfere on lifestyle interventions is unclear. We assessed associations of selected SNPs with changes induced by a lifestyle intervention.

METHODS

This 9-month intervention on diet and physical activity included 180 Brazilians at high cardiometabolic risk, genotyped for the TNF-α -308 G/A, IL-6 -174 G/C and AdipoQ 45 T/G SNPs. Changes in metabolic and inflammatory variables were analyzed according to these SNPs. Individuals with at least one variant allele were grouped and compared with those with the reference genotype.

RESULTS

In the entire sample (66.7% women; mean age 56.5 ± 11.6 years), intervention resulted in lower energy intake, higher physical activity, and improvement in anthropometry, plasma glucose, HOMA-IR, lipid profile and inflammatory markers, except for IL-6 concentrations. After intervention, only variant allele carriers of the TNF-α -308 G/A decreased plasma glucose, after adjusting for age and gender (OR 2.96, p = 0.025). Regarding the IL6 -174 G/C SNP, carriers of the variant allele had a better response of lipid profile and adiponectin concentration, but only the reference genotype group decreased plasma glucose. In contrast to individuals with the reference genotype, carriers of variant allele of AdipoQ 45 T/G SNP did not change plasma glucose, apolipoprotein B, HDL-c and adiponectin concentrations in response to intervention.

CONCLUSION

The TNFα -308 G/A SNP may predispose a better response of glucose metabolism to lifestyle intervention. The IL-6 -174 G/C SNP may confer a beneficial effect on lipid but not on glucose metabolism. Our findings reinforce unfavorable effects of the AdipoQ 45 T/G SNP in lipid profile and glucose metabolism after intervention in Brazilians at cardiometabolic risk. Further studies are needed to direct lifestyle intervention to subsets of individuals at cardiometabolic risk.

Amerindians show association to obesity with adiponectin gene SNP45 and SNP276: population genetics of a food intake control and "thrifty" gene

Adiponectin gene polymorphisms SNP45 and SNP276 have been related to metabolic syndrome (MS) and related pathologies, including obesity. However results of associations are contradictory depending on which population is studied. In the present study, these adiponectin SNPs are for the first time studied in Amerindians. Allele frequencies are obtained and comparison with obesity and other MS related parameters are performed. Amerindians were also defined by characteristic HLA genes. Our main results are: (1) SNP276 T is associated to low diastolic blood pressure in Amerindians, (2) SNP45 G allele is correlated with obesity in female but not in male Amerindians, (3) SNP45/SNP276 T/G haplotype in total obese/non-obese subjects tends to show a linkage with non-obese Amerindians, (4) SNP45/SNP276 T/T haplotype is linked to obese Amerindian males. Also, a world population study is carried out finding that SNP45 T and SNP276 T alleles are the most frequent in African Blacks and are found significantly in lower frequencies in Europeans and Asians. This together with the fact that there is a linkage of this haplotype to obese Amerindian males suggest that evolutionary forces related to famine (or population density in relation with available food) may have shaped world population adiponectin polymorphism frequencies.

Association of adiponectin gene functional polymorphisms (-11377C/G and +45T/G) with nonalcoholic fatty liver disease

Adiponectin levels are reduced in NAFLD patients and genetic variants of adiponectin have been frequently associated with type 2 diabetes and insulin resistance. To determine the genotypic frequencies of adiponectin functional polymorphisms (-11377C/G and +45T/G) and their subsequent effect on disease progression and plasma adiponectin levels in the patients with NAFLD. A total of 137 NAFLD patients and 250 matched controls were enrolled in the study. DNA sequencing and genotyping were performed to identify the genetic variants. The plasma adiponectin levels were assessed by ELISA. Homozygous mutant genotype of adiponectin SNPs, -11377C/G and +45T/G, were significantly more prevalent in NAFLD patients than controls (Bonferroni corrected p=0.014 and 0.018, respectively). Plasma adiponectin levels were significantly lower in the NAFLD patients as compared to controls. Moreover, presence of 'G' allele at position -11377C/G and +45T/G was found to be associated with necroinflammatory grade and reduced adiponectin levels, (p values 0.02 and 0.01) respectively. -11377G and +45G alleles are associated with severity of liver disease and hypoadiponectemia, in the patients with NAFLD, respectively.

Polymorphism of adiponectin (45T/G) and adiponectin receptor-2 (795G/A) in an Iranian population: relation with insulin resistance and response to treatment with pioglitazone in patients with type 2 diabetes mellitus

Adiponectin, an adipose-derived plasma protein, is reduced in patients with obesity and type 2 diabetes. Thiazolidinediones can increase adiponectin levels and improve insulin sensitivity. This study investigated the associations between type 2 diabetes and two single-nucleotide polymorphisms in the adiponectin (45T/G) and adiponectin receptor-2 gene (795G/A), and investigated whether these genetic variants affect the response to pioglitazone in Iranian patients with type 2 diabetes. We genotyped 128 non-diabetic participants and 101 patients with type 2 diabetes for 45T/G and 795G/A with polymerase chain reaction-restriction fragment length polymorphism assays. Patients were treated with pioglitazone for 12 weeks, after which we compared laboratory parameters in these two groups. Fasting blood sugar differed significantly in individuals with different 795G/A genotypes after pioglitazone treatment (P = 0.009). The mean decrease in insulin/glucose ratio after treatment also differed significantly in individuals with different 45T/G genotypes (P = 0.035). The T allele frequency for 45T/G was 87.11% in controls versus 81.68% in patients (P = 0.071). The TG and GG genotypes were more frequent in patients (P = 0.032). The G allele frequency for 795G/A was 76.17% in controls versus 80.20% in patients (P = 0.179). 795G/A variants were not significantly different between patient and control group. The adiponectin gene 45T/G mutation may be an important determinant of type 2 diabetes in the Iranian population. However, adiponectin 45T/G and adiponectin receptor-2 795G/A polymorphisms were not significantly associated with the response to pioglitazone in our sample.