Epigenetics could contribute to explain individual differences in weight loss after an energy restriction intervention. Here, we identify novel potential epigenetic biomarkers of weight-loss comparing DNA methylation patterns of high and low responders to a 2 hypocaloric diet. Twenty-five overweight/obese men followed an 8-week caloric restriction intervention. DNA was isolated from peripheral blood mononuclear cells and treated with bisulfite. The basal and endpoint epigenetic differences between high and low responders were analysed by methylation microarray, which was also useful to compare the epigenetic changes due to the nutrition intervention. Subsequently, Sequenom EpiTYPER technology was used to validate several relevant CpGs and the surrounding regions.DNA methylation levels in several CpGs located in ATP10A and CD44 genes showed statistical baseline differences depending on the weight-loss outcome. At the treatment endpoint, DNA methylation levels of several CpGs on WT1 promoter were statistically more methylated in the high than in the low responders. Finally, different CpG sites from WT1 and ATP10A were significantly modified as a result of the intervention.In summary, hypocaloric diet-induced weight loss in humans could alter DNA methylation status of specific genes. Moreover, baseline DNA methylation patterns may be used as epigenetic markers that could help to predict weight loss.

Subjects with higher plasma leptin and lower ghrelin levels at baseline could be more prone to regain lost weight, and hormones levels could be proposed as biomarkers for predicting obesity-treatment outcomes.

Leptin is an adipokine involved in body weight and food intake regulation whose promoter region presents CpG islands that could be subject to dynamic methylation. This methylation process could be affected by environmental (e.g. diet) or endogenous (e.g., adipocyte differentiation, inflammation, hypoxia) factors, and could influence adipocyte leptin gene expression. The aim of this article was to study whether a high-energy diet may affect leptin gene promoter methylation in rats. A group of eleven male Wistar rats were assigned into two dietary groups, one fed on a control diet for 11 weeks and the other on a high-fat cafeteria diet. Rats fed a high-energy diet become overweight and hyperleptinemic as compared to the controls. DNA isolated from retroperitoneal adipocytes was treated with bisulfite and a distal portion of leptin promoter (from -694 to -372 bp) including 13 CpG sites was amplified by PCR and sequenced. The studied promoter portion was slightly more methylated in the cafeteria-fed animals, which was statistically significant (p < 0.05) for one of the CpG sites (located at the position -443). In obese rats, such methylation was associated to lower circulating leptin levels, suggesting that this position could be important in the regulation of leptin gene expression, probably by being a target sequence of different transcription factors. Our findings reveal, for the first time, that leptin methylation pattern can be influenced by diet-induced obesity, and suggest that epigenetic mechanisms could be involved in obesity by regulating the expression of important epiobesigenic genes.