Decreased levels of whole blood glial cell line-derived neurotrophic factor (GDNF) in remitted patients with mood disorders

Recent post-mortem and imaging studies provide evidence for a glial reduction in different brain areas in mood disorders. This study was aimed to test whether glial cell line-derived neurotrophic factor (GDNF), a member of transforming growth factor (TGF)- β superfamily, in blood levels was associated with mood disorders. We measured GDNF and TGF- β levels in whole blood in remitted patients with mood disorders [ n =56; major depressive disorders (MDD) 39, bipolar disorders (BD) 17] and control subjects ( n =56). GDNF and TGF- β were assayed with the sandwich ELISA method. Total GDNF levels were significantly lower in MDD and in BD than in control subjects (MDD, p =0.0003; BD, p =0.018), while no significant difference in total TGF- β 1 or total TGF- β 2 levels was found in these groups. Our study suggests that lower GDNF levels might be involved in the pathophysiology of mood disorders, although this preliminary study has several limitations.