Estrogen receptor α is not a candidate gene for metabolic syndrome in Caucasian elderly subjects

Transcription factor 7-like 2 polymorphism and context-specific risk of metabolic syndrome, type 2 diabetes, and dyslipidemia

BACKGROUND

The transcription factor 7-like 2 gene (TCF7L2) is an element of the Wnt signaling pathway. There is lack of evidence if TCF7L2 has a functional role in lipid metabolism and regulation of the components constitutes the metabolic syndrome (MetSyn). The aims of this study were to evaluate whether the risk allele of TCF7L2 gene polymorphism is associated with dyslipidemia and MetSyn.

MATERIALS AND METHODS

The MetSyn subjects were participated only based on the National Cholesterol Education Program - Third Adult Treatment Panel criteria. In this case-control study, the DNA from MetSyn patients without (n = 90) and with type 2 diabetes (T2D) (n = 94) were genotyped.

RESULTS

The results show that the genotype-phenotype for CC, CT/TT of TCF7L2 gene polymorphism correlated with body mass index and waist circumference in MetSyn and MetSyn + T2D subjects (r = -0.949 and r = -0.963, respectively). The subjects that only possess MetSyn but are not diabetics show the 2 h postprandial glucose and fasting blood glucose, glycated hemoglobin significantly lower (P < 0.05) than those subjects have both abnormality. The level of triglyceride in CT/TT carriers in MetSyn was higher than CC carriers (P = 0.025). A comparison with the controls subjects, the frequencies of the T allele in the groups of MetSyn (46.66%) and MetSyn + T2D (47.34%) show significantly different (P < 0.05). The odds ratios for T allele in (MetSyn)/(normal), (MetSyn + T2D)/(normal), and in (MetSyn + T2D)/(MetSyn) were 3.59 (95% confidence interval [CI], 1.33-9.67, P = 0.0093), 3.76 (95% CI, 1.40-10.07, P = 0.0068), and 1.08 (95% CI: 0.55- 2.11, P = 0.834), respectively.

CONCLUSION

The results revealed the important insights essential for the role of TCF7L2 that the T allele of TCF7L2 plays a significant role in the susceptibility to dyslipidemia, MetSyn, and T2D.

Associations of estrogen receptor alpha and Beta gene polymorphisms with lipid levels and insulin resistance in men

OBJECTIVE

The association of four single nucleotide polymorphisms in estrogen receptor alpha (ESR1) and beta (ESR2) genes with lipid levels and insulin resistance in men.

DESIGN AND METHODS

Lipids, glucose, insulin and HOMA-IR were determined, in a population-based, cross-sectional, cohort of 170 apparently healthy middle-aged Greek men, along with body mass index (BMI), waist circumference (WC) and percentage of body fat content (%fat). Genotyping of ESR1 for PvuII and XbaI and ESR2 for RsaI and AluI polymorphisms was performed.

RESULTS

Associations of AluI with LDL-Chol (mean ± SD, aa 4.3 ± 1.1 vs. Aa 3.7 ± 1.0 and ΑΑ 4.2 ± 1.1, p = 0.023) and RsaI with HOMA-IR [median (IQR), RR 1.55 (0.88-2.49) vs. Rr/rr 1.69 (0.72-2.29), p = 0.032] were found. Synergistic effects of RsaI and AluI of ESR2 gene on LDL-Chol levels, %fat and WC, as well as a synergistic effect of both ESR1 and ESR2 genes on levels of TChol (p = 0.01) and LDL-Chol (p = 0.027) were also shown. These findings remained significant after adjustment for potential confounders. Significant independent associations of PvuII with %fat (mean ± SD, pp 24.6 ± 5.3 vs Pp 22.4 ± 5.2 and PP 21.2 ± 6.7, p = 0.044), and RsaI with %fat (RR 22.6 ± 5.5 vs. Rr/rr 25.2 ± 6.3, p = 0.015) and WC (mean ± SD, RR 97.4 ± 10.4 vs. Rr/rr 102.6 ± 12.6, p = 0.013) were found. Synergistic effects on %fat, between the ESR1 polymorphisms (p = 0.004), between the ESR2 polymorphisms and among all four ESR polymorphisms studied were also present.

CONCLUSIONS

ESR2 is associated with LDL-Chol levels and HOMA-IR in men independently of confounders. Body fat is affected by both genes. Furthermore, a synergistic effect of ESR1 and ESR2 on TChol, LDL-Chol and %fat, was shown.