title: Decreased plasma levels of brain-derived neurotrophic factor (BDNF) during mixed episodes of bipolar disorder.
abstract: BACKGROUND
  Brain-derived neurotrophic factor (BDNF) is a neurotrophin involved in neurogenesis and neuroplasticity. Decreased blood levels of BDNF have been found during acute manic and depressive states. BDNF has been proposed as a biomarker in illness phases of mood disorders. No information is available regarding BDNF levels during the mixed states of bipolar disorder (BD). The aim of this study was to evaluate BDNF levels during mixed episodes of BD patients and compare them with those of healthy subjects and depressed patients.
  
  
  METHODS
  Plasma BDNF levels were measured by an ELISA assay in 18 patients with major depressive episode (MDE), 19 patients with mixed episode (ME) and 15 healthy subjects (HS).
  
  
  RESULTS
  BDNF levels were significantly higher in HS, as compared with patients׳ samples (HS vs. MDE patients: p<001; HS vs. ME patients: p=.022). No significant differences were found between BDNF levels of ME and MDE patients. The severity of illness as assessed by CGI-S was significantly higher in ME than in MDE patients (p=.01).
  
  
  CONCLUSIONS
  The small sample size may have weakened the power of statistical analyses. All patients received mood-stabilizing and antidepressant treatments which have been reported to influence peripheral BDNF levels.
  
  
  CONCLUSIONS
  Our results are consistent with previous studies showing reduced BDNF during both manic and depressive episodes. This finding supports the role of BDNF as a state-marker of mood episodes, and may represent a contribution to a unitary approach model between unipolar and BDs, as well as to the manic-depressive spectrum model.
authors.affiliation: Department of Clinical and Experimental Medicine, University of Pisa, Via Savi 10, 56126 Pisa, Italy. Electronic address: armando.piccinni@gmail.com.
authors.forename: Armando
authors.initials: A
authors.lastname: Piccinni
authors.affiliation: Department of Clinical and Experimental Medicine, University of Pisa, Via Savi 10, 56126 Pisa, Italy.
authors.forename: Antonello
authors.initials: A
authors.lastname: Veltri
authors.affiliation: Department of Clinical and Experimental Medicine, University of Pisa, Via Savi 10, 56126 Pisa, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Costanzo
authors.affiliation: Department of Clinical and Experimental Medicine, University of Pisa, Via Savi 10, 56126 Pisa, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Vanelli
authors.affiliation: Department of Clinical and Experimental Medicine, University of Pisa, Via Savi 10, 56126 Pisa, Italy.
authors.forename: Caterina
authors.initials: C
authors.lastname: Franceschini
authors.affiliation: Department of Clinical and Experimental Medicine, University of Pisa, Via Savi 10, 56126 Pisa, Italy.
authors.forename: Ilenia
authors.initials: I
authors.lastname: Moroni
authors.affiliation: Neuroscience Institute, National Research Council, Via Moruzzi 1, 56124 Pisa, Italy; Department DISCAB, University of L'Aquila, Via Vetoio, 67100 L'Aquila, Italy.
authors.forename: Luciano
authors.initials: L
authors.lastname: Domenici
authors.affiliation: Neuroscience Institute, National Research Council, Via Moruzzi 1, 56124 Pisa, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Origlia
authors.affiliation: Department of Clinical and Experimental Medicine, University of Pisa, Via Savi 10, 56126 Pisa, Italy.
authors.forename: Donatella
authors.initials: D
authors.lastname: Marazziti
authors.affiliation: International Mood Center, University of California, San Diego, CA, USA.
authors.forename: Hagop Souren
authors.initials: HS
authors.lastname: Akiskal
authors.affiliation: Department of Clinical and Experimental Medicine, University of Pisa, Via Savi 10, 56126 Pisa, Italy.
authors.forename: Liliana
authors.initials: L
authors.lastname: Dell'Osso
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood; D001714:Bipolar Disorder / Q000097:blood*; D019208:Brain-Derived Neurotrophic Factor / Q000097:blood*; D003865:Major Depressive Disorder / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; D019208:Brain-Derived Neurotrophic Factor
keywords: BDNF; Biomarkers; Bipolar disorder; Bipolar spectrum; DSM-5; Mixed state