Effect of treatment on serum glial cell line-derived neurotrophic factor in depressed patients

Post-mortem studies have demonstrated a decreased number of glia, reduced glial density, and a decreased glia/neuron ratio in different brain areas of patients diagnosed with a major depressive disorder (MDD). Researchers have therefore suggested that neurotrophic growth factor systems might be involved in the aetiology of MDD. This study aimed to test whether glial cell line-derived neurotrophic factor (GDNF), a member of the transforming growth factor beta family, in serum was associated with MDD. Serum concentrations were measured in MDD patients before treatment (n=76), after 8 weeks of antidepressant treatment (n=39), and in control subjects (n=50) using a sandwich ELISA method. Serum GDNF was significantly lower in MDD patients before treatment than in control subjects (P0.001). From baseline to remission after 8 weeks of treatment, the increase in serum GDNF was statistically significant (P0.001). The present study suggests that lower serum GDNF might be involved in the pathophysiology of MDD and antidepressant treatment increases the GDNF in MDD.