Association between metabolic status and the methylation level of genes involved in metabolic disorders and obesity

Abstract

Objectives: DNA methylation is one of the epigenetic mechanims to control gene expression, and it is believed to be modulated by environmental and nutritional factors. Thus, epigenetics provides a mechanism which may explain the etiology of type 2 diabetes and obesity. The aim of this study is to analyse the methylation level in visceral adipose tissue (VAT) of PPARa, RXRa, LPL and LEP, genes related to the HOMAIR and BMI. Methods: A total of 61 VAT samples were obtained during bariatric or hiatal hernia surgeries. Biochemical parameters from these patients were measured. Samples were assigned to four groups attending their BMI:: normalweigh, overweigh, obese and morbidly obese (<25, 25.1-30, 30.1- 40, >40.1). Furthermore, the patients were classified in two groups ac- cording to the HOMA-IR (HOMA-IR<4 and HOMA-IR 4.1-7.5). Methylation level was measured through pyrosequentation, using the Pyromark tech- nology and predesigned CpG methylation assays (Qiagen). The results were analyzed using the CpG methylation software (Qiagen) and the sta- tistical package SPSS. Results: We found a negative correlation between RXRa methylation level and the BMI. In the case of PPARa existed a positive correlation with the HOMA-IR, while LPL correlated positively with both, preprandial and postprandial triglycerid levels, and with the HOMA-IR. Furthermore, we found significative differences in the methylation levels of PPARa by BMI and HOMA-IR, and by HOMA-IR for LPL Conclusion: A relationship exists between the methylation level of the studied genes and the HOMA-IR and BMI. Moreover,there is an association of PPARa with the BMI and LPL with the metabolic state.