Assessment of Mature Serum Brain-Derived Neurotrophic Factor (BDNF) is Not Superior to Total Serum BDNF in Prediction of Antidepressant Treatment Outcome

BackgroundSerum BDNF levels are decreased in major depressive disorder (MDD) and tend to normalize under antidepressant treatment, serving as a treatment outcome predictor. BDNF is initially synthetized as precursor protein proBDNF and is cleaved to mature BDNF (mBDNF) while only the latter exerts neurotrophic activity.AimThe aim was to explore if a specific enzyme-linked immunosorbent assay (ELISA) kit for mBDNF in serum would be superior to the unspecific assessment of total serum BDNF in predicting treatment response in MDD.MethodsTwenty-five patients with MDD underwent standardized treatment with duloxetine. Severity of depression was measured by Hamilton Depression Rating Scale (HDRS) at baseline (BL), after one (W1), two (W2) and six weeks (W6) of treatment. Treatment response was defined as a HDRS ≥ 50% reduction of BL score at W6. mBDNF and total BDNF serum levels were determined at BL, W1 and W2.ResultsA high and stable correlation was found between mBDNF and total BDNF serum levels over all measurements. The predictive value of mBDNF BL levels and mBDNFΔW1 to response was similar to that of total BDNF BL and total BDNFΔW1. The assessment of serum mBDNF was not superior to total BDNF in prediction of treatment outcome.ConclusionsNot only baseline total BDNF but also mBDNF is predictive to treatment outcome. The later might represent the main player in this respect, which supports the idea of a functional link between neuroplasticity and MDD.Disclosure of interestThe authors have not supplied their declaration of competing interest.