Brain-derived neurotrophic factor as a possible a biomarker of bipolar disorder activity

  • Dr Brisa Fernandes, Bipolar Disorder Program and Laboratory of Molecular Psychiatry, Hospital de Clínicas de Porto Alegre, Brazil, and INCT for Tra, Brazil
  • Dr Fabiano Gomes, Hospital de Clínicas de Porto Alegre, Brazil, and INCT for Tra, Brazil
  • Gabriel Fries, Bipolar Disorder Program and Laboratory of Molecular Psychiatry, Hospital de Clínicas de Porto Alegre, Brazil, and INCT for Tra, Brazil
  • Laura Stertz, Hospital de Clínicas de Porto Alegre, Brazil
  • Dr Keila Cereser, Bipolar Disorder Program and Laboratory of Molecular Psychiatry, Hospital de Clínicas de Porto Alegre, Brazil, and INCT for Tra, Brazil
  • Cristina Pessoa, Hospital de Clínicas de Porto Alegre, Brazil
  • Dr Clarissa Gama, Hospital de Clínicas de Porto Alegre, Brazil, and INCT for Tra, Brazil
  • Dr Flavio Kapczinski, Hospital de Clínicas de Porto Alegre, Brazil

Introduction: Serum BDNF has been considered a biomarker of activity of bipolar disorder. We set out to assess the properties of serum BDNF levels as a biomarker using Receiver operating characteristics (ROC) curves.
Methods: An exploratory study with 32 patients with BD in manic episode, 20 in depressive episode, 32 in euthymia and 32 controls. Serum BDNF levels were expressed as pg/ug protein. Optimal sensitivity and specificity of serum BDNF for the evaluation of disorder activity in BD were determined by the ROC curve analysis.
Results: Sample: mean age of 40.09 ± 11.39 years (mean ± SD). Forty-four of the 116 subjects (38.30%) were male. Serum BDNF levels during mania and depression were decreased when compared to patients during euthymia and to controls. ROC curve analysis was used to explore discriminatory values of BDNF. The area under the curve of the ROC analysis in mania vs. control was 0.72 (ranged from 0.58 to 0.86). A proposed ‘‘best” cutoff of 0.19 resulted in 75% sensitivity and 50% specificity. The area under the curve of the ROC analysis in depression vs. control was 0.76 (ranged from 0.62 to 0.90). A proposed cutoff of 0.18 resulted in 85% sensitivity and 50% specificity.
Conclusions: Our results suggest that serum BDNF levels may be a useful biomarker of disorder activity in the manic and depressive episodes of BD.