Leptin predicts cortical and subcortical gray matter volume recovery in alcohol dependent patients: A longitudinal structural magnetic resonance imaging study

The neuroprotective effects of leptin and its role in addictive disorders has been highlighted by several recent studies. However, its potential effects on morphological alterations in alcohol dependence are yet to be investigated. Associations between leptin and the longitudinal courses of gray matter volume (GMV) and cortical thickness (CT) were investigated in N = 62 alcohol-dependent patients that underwent structural magnetic resonance imaging after a mean abstinence of 12 (baseline) and 27 days (follow-up) respectively. Blood samples were collected at baseline to determine leptin levels. A cohort of N = 74 healthy individuals served as a reference sample. At baseline, alcohol-dependent patients compared to healthy controls displayed smaller GMV in the insula, parts of the superior, middle and inferior frontal gyri and hippocampal regions and thinner CT in the insula, parts of the superior and middle frontal cortices, the lateral orbitofrontal cortex and parts of the occipital and lingual cortices that partially recovered during abstinence (p(FWE) < 0.05). In alcohol-dependent patients, leptin was a significant predictor of GMV and CT recovery in the areas that showed the strongest whole-brain effects, specifically GMV in the right insula (R-2 = 0.070, p(FDR )= 0.040) and left inferior frontal triangular gyrus (R 2 = 0.076, pFDR = 0.040), as well as CT in the left insula (R-2 = 0.158, p(FDR) = 0.004) and right superior frontal cortex (R-2 = 0.180, p(FDR) = 0.004). Present results support the role of leptin in predicting GMV and CT recovery during the first month of abstinence in alcohol-dependent patients.