Tumor necrosis factor alpha -308 promoter polymorphism and insulin resistance inoverweight and obese adolescent

Abstract

Study Model/Methodology: This is a cross-sectional study with a sample of 104 overweight/obese adolescents, with a mean weight of 52.98 kg ± 22.00, mean age 16.01 ± 2.91 years. We used the homeostasis model assessment-estimated IR (HOMA-IR) index to quantify the insulin resistance (IR). The -308 polymorphism of the promoter of TNF-α was performed using polymerase chain reactionrestriction fragment length polymorphism technique. Statistical analysis of the quantitative measures was conducted with a student’s t-test. For correlation between the genotype and alleles, we used chisquare statistical test. To test the heterogeneity between HOMA-IR and the anthropometric parameters the Mann-Whitney test was used, associated with the Hardy-Weinberg equilibrium. The association between -308G/A polymorphism of the promoter of TNF-α and HOMA-IR was tested by univariate linear regression analysis. Objective: Investigate the association between -308G/A polymorphism in the promoter of tumor necrosis factor-alpha (TNF-α) and susceptibility to IR in overweight/obese adolescents. Results: The prevalence of IR was 18.30% according to the HOMA-IR. The frequency of GG, AG and AA genotype was found 75 (72.12%), 28 (26.92%) and 1.0 (0.96%) respectively. Allele frequencies for guanine (G) and adenine (A) were 178 (85.58%) and 30 (14.42%), respectively. The allele A as well as GA and AA genotype contributed to increase RI (14.42% and 27.88% respectively). Conclusion: The - 308 G/A polymorphism of the promoter of TNF-α can contribute to the IR increase in obese adolescents with GA and AA genotypes.

Obesity and the role of genetic polymorphism: A review of genes as the risk of obesity

“…Other studies have also found that AA and GA genotypes are more common in male obese individuals, whereas in female individuals AG genotype is associated with a higher risk of obesity. 71 In another study in Brazil, -308G/A polymorphism in TNF-α promoters, A allele, GA, and AA genotypes contribute to increased insulin resistance and excess body weight in adult. 73 In the Javanese population, this gene polymorphism showed that GA genotype patients have lipid and TNF-α levels higher than the GG genotype, and variation of -308 G/A TNF-α gene plays a role in a higher risk of obesity, 74,75 risk of breast cancer, 76 hypertension, 77 and inflammatory bowel disease.…”

“…Activation of the immunologic system during infection or injury causes metabolic changes. 71 TNF-α is expressed on the surface of transmembrane protein cells and is involved in the pathogenesis of various inflammatory diseases. The TNF-α gene is located on chromosome 6.p21.1-21.3.…”