Clinical Medicine Insights: Psychiatry

We investigated the serum protein profiles of subjects with major depressive disorder (MDD), with (n = 4) and without clinical improvement (n = 4), at the initiation of antidepressant treatment (venlafaxine) (T0) and 4 weeks later (T28), by difference gel electrophoresis in two dimensions (2D-DIGE) and mass spectrometry. The nine proteins displaying differences in composition between the two time points in the group with clinical improvement between T0 and T28 included gelsolin, clusterin, and the activated fragment of complement C3 (C3a). We then analyzed serum samples from MDD subjects receiving different antidepressants between T0 and T28. Subjects were classified into two groups, with (n = 17) or without (n = 14) clinical improvement (>50% decrease in baseline Hamilton Depression Rating Scale score), at T28. Clusterin levels did not differ between groups at either time point. Gelsolin and C3a levels differed between T0 and T28 only in the group presenting clinical improvement. A comparison with serum samples from controls suggested that the levels of these two proteins changed during MDD and were potentially modified after successful antidepressant treatment. Despite the small sample size, the results of this pilot study suggest that several changes in the expression of some serum proteins occur in association with the clinical relevance of the treatment, and indicate changes to general pathways requiring further study.