Smoking-induced changes in leptin serum levels and c/EBPalpha-related methylation status of the leptin core promotor during smoking cessation

Introduction:

Previous studies have provided evidence of an association between serum leptin levels and smoking as well as craving during smoking cessation. As promoter methylation also regulates leptin expression, we investigated the leptin gene promoter region of smokers before and after smoking cessation. Since leptins core promoter region contains an essential c/EBPalpha transcription binding site, we narrowed our investigation to C-300 (-300 base pairs from the transcription start site) of that binding site.

Methods:

Fasted blood samples were drawn from tobacco dependent patients on the first day (T0, right after smoking the last cigarette), as well as on day 7 (T7) and day 14 (T14) after smoking cessation on T0. Leptin measurement was performed using the human leptin ELISA. Methylation status of the leptin core promotor was analysed.

Results:

Female smokers showed hypermethylation of C-300 compared to non-smokers. Global methylation status is associated with higher craving and the degree of dependence in female smokers. Serum leptin levels in female smokers were significantly higher than in non-smokers.

Conclusion:

These findings support previous results and, for the first time, point to a pathophysiological role of c/EBPalpha-related C-300 methylation in tobacco dependence.