title: Decreased serum levels of mature brain-derived neurotrophic factor (BDNF), but not its precursor proBDNF, in patients with major depressive disorder.
abstract: BACKGROUND
  Meta-analyses have identified serum levels of brain-derived neurotrophic factor (BDNF) as a potential biomarker for major depressive disorder (MDD). However, at the time, commercially available human ELISA kits are unable to distinguish between proBDNF (precursor of BDNF) and mature BDNF because of limited BDNF antibody specificity. In this study, we examined whether serum levels of proBDNF, mature BDNF, and matrix metalloproteinase-9 (MMP-9), which converts proBDNF to mature BDNF, are altered in patients with MDD.
  
  
  RESULTS
  Sixty-nine patients with MDD and 78 age- and gender-matched healthy subjects were enrolled. Patients were evaluated using 17 items on the Structured Interview Guide for the Hamilton Depression Rating Scale. Cognitive impairment was evaluated using the CogState battery. Serum levels of proBDNF, mature BDNF, and MMP-9 were measured using ELISA kits. Serum levels of mature BDNF in patients with MDD were significantly lower than those of normal controls. In contrast, there was no difference in the serum levels of proBDNF and MMP-9 between patients and normal controls. While neither proBDNF nor mature BDNF serum levels was associated with clinical variables, there were significant correlations between MMP-9 serum levels and the severity of depression, quality of life scores, and social function scores in patients.
  
  
  CONCLUSIONS
  These findings suggest that mature BDNF may serve as a biomarker for MDD, and that MMP-9 may play a role in the pathophysiology of MDD. Further studies using larger sample sizes will be needed to investigate these results.
authors.affiliation: Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, Chiba, Japan.
authors.forename: Taisuke
authors.initials: T
authors.lastname: Yoshida
authors.forename: Masatomo
authors.initials: M
authors.lastname: Ishikawa
authors.forename: Tomihisa
authors.initials: T
authors.lastname: Niitsu
authors.forename: Michiko
authors.initials: M
authors.lastname: Nakazato
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Watanabe
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Shiraishi
authors.forename: Akihiro
authors.initials: A
authors.lastname: Shiina
authors.forename: Tasuku
authors.initials: T
authors.lastname: Hashimoto
authors.forename: Nobuhisa
authors.initials: N
authors.lastname: Kanahara
authors.forename: Tadashi
authors.initials: T
authors.lastname: Hasegawa
authors.forename: Masayo
authors.initials: M
authors.lastname: Enohara
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kimura
authors.forename: Masaomi
authors.initials: M
authors.lastname: Iyo
authors.forename: Kenji
authors.initials: K
authors.lastname: Hashimoto
mesh_terms: D000328:Adult; D019208:Brain-Derived Neurotrophic Factor / Q000097:blood*; D016022:Case-Control Studies; D003710:Demography; D003865:Major Depressive Disorder / Q000097:blood* / Q000201:enzymology; D005260:Female; D006801:Humans; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000097:blood; D008875:Middle Aged; D011498:Protein Precursors / Q000097:blood*; D055815:Young Adult
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D011498:Protein Precursors; C426674:brain-derived neurotrophic factor precursor; D020780:Matrix Metalloproteinase 9