Promoter Methylation of LEP and LEPR before and after Bariatric Surgery: A Cross-Sectional Study

Abstract

<b><i>Introduction:</i></b> DNA methylation constitutes one important epigenetic mechanism that regulates gene expression in human cells. With regard to obesity, bariatric surgery-induced weight loss has been associated with promoter methylation changes in several genes. Hyperleptinemia is a characteristic feature of obesity. The underlying regulating mechanisms have not yet been completely elucidated. <b><i>Methods:</i></b> We investigated the methylation of the promoters of the leptin gene (<i>LEP</i>) and the leptin receptor gene (<i>LEPR</i>) as well as leptin expression in pre- and postbariatric surgery patients using a comparative cross-sectional design. <b><i>Results:</i></b> Our results revealed significantly higher <i>LEP</i> promoter methylation patterns in prebariatric surgery patients compared to postoperatively. DNA methylation of the <i>LEPR</i> promoter was significantly higher in the postoperative group. Moreover, we found significantly higher leptin serum levels in patients before the bariatric surgery than afterwards. <b><i>Discussion:</i></b> These findings strengthen the suggestion that there is an association between LEP expression and <i>LEP</i> methylation in obesity. We suggest that the epigenetic profile of <i>LEP</i> might be influenced by leptin serum levels in the form of a regulating feedback mechanism.