Assessment of serum levels of mature brain-derived neurotrophic factor (mBDNF) is not superior to total (tot)BDNF in prediction of antidepressant treatment outcome

Abstract

Background/Aims: Serum BDNF levels are commonly decreased in major depression, and low baseline BDNF serum levels are predictive to poor treatment outcome [1]. In most previous clinical studies, total (tot)BDNF was assessed with enzyme-linked immunosorbent assay (ELISA) kits that did not distinguish between precursor protein proBDNF and mature (m)BDNF. Therefore, our aim was to explore if assessment of mBDNF in serum would be superior to assessment of totBDNF in predicting treatment response in major depression. Methods: In a sample of twenty-five patients with major depressive disorder who underwent a standardized treatment with duloxetine over six weeks, severity of depression (Hamilton Depression Rating Scale (HDRS)), mBDNF and totBDNF were assessed at baseline and after one and six weeks of treatment. Treatment response was defined as a HDRS ≥ 50% reduction of baseline score at week 6. Results: Serum levels of mBDNF and totBDNF were strongly and positively correlated. In responders (N = 18), baseline serum levels of both, mBDNF and totBDNF, were significantly higher than in non-responders (N = 7). Moreover, a steep early rise between baseline and week 1 of both, mBDNF and totBDNF, was associated with poor treatment outcome. Conclusion: Due to the high correlation between mBDNF and totBDNF serum levels, assessment of mBDNF was not superior to totBDNF in prediction of treatment response.