BDNF CpG methylation and serum levels covary during alcohol withdrawal in patients with alcohol use disorder: A pilot study.

OBJECTIVES:Brain-derived neurotrophic factor (BDNF) levels vary in various conditions including alcohol use disorder (AUD). We aimed to identify drivers of these variations. METHODS:Twelve patients with AUD were assessed at hospitalisation for alcohol withdrawal and four months later. We looked for associations between the change in serum BDNF levels and (1) length of abstinence, (2) anxiety (Hamilton Anxiety Scale) and depression (Beck-Depression Inventory), (3) one functional BDNF genotype (rs6265) and (4) methylation levels of 12 CpG sites within the BDNF gene (located in exons I, IV and IX). RESULTS:While abstinence remained, serum BDNF level increased. This increase correlated with the variation of methylation levels of the BDNF gene, and more specifically of exon I. We found no significant effect of length of abstinence, rs6265, depression or anxiety on serum BDNF level. CONCLUSIONS:Epigenetic regulation of the BDNF gene may be involved in variations of BDNF blood level associated with alcohol abstinence.