title: Brain-derived neurotrophic factor and subcallosal deep brain stimulation for refractory depression.
abstract: OBJECTIVE
  Subcallosal cingulate (SCC) deep brain stimulation (DBS) is a promising experimental treatment for treatment-resistant depression (TRD). Given the role of brain-derived neurotrophic factor (BDNF) in neuroplasticity and antidepressant efficacy, we examined the effect of SCC-DBS on serum BDNF in TRD.
  
  
  METHODS
  Four patients with TRD underwent SCC-DBS treatment. Following a double-blind stimulus optimization phase of 3 months, patients received continuous stimulation in an open label fashion for 6 months. Clinical improvement in depressive symptoms was evaluated bi-weekly for 6 months using the Hamilton Depression Rating Scale (HDRS). Mature serum BDNF levels were measured before and 9-12 months after surgery.
  
  
  RESULTS
  Three patients responded to SCC-DBS: two showed full clinical response (50% reduction in HDRS scores) and one had partial response (35% reduction in HDRS scores) at the clinical endpoint. Interestingly, all four patients showed reduction in serum BDNF concentration from pre-DBS baseline.
  
  
  CONCLUSIONS
  SCC-DBS for TRD may be associated with decreased levels of serum BDNF. Longitudinal studies with multiple measurements in a larger sample are required to determine the role of BDNF as a biomarker of SCC-DBS antidepressant efficacy.
authors.affiliation: Departments of Psychiatry, University of Calgary , Calgary, AB , Canada.
authors.forename: Rajamannar
authors.initials: R
authors.lastname: Ramasubbu
authors.forename: Haley A
authors.initials: HA
authors.lastname: Vecchiarelli
authors.forename: Matthew N
authors.initials: MN
authors.lastname: Hill
authors.forename: Zelma H T
authors.initials: ZH
authors.lastname: Kiss
mesh_terms: D015415:Biomarkers / Q000097:blood; D019208:Brain-Derived Neurotrophic Factor / Q000097:blood*; D046690:Deep Brain Stimulation; D003865:Major Depressive Disorder / Q000628:therapy*; D061218:Depressive Disorder, Treatment-Resistant / Q000628:therapy*; D005260:Female; D006179:Gyrus Cinguli / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; D019208:Brain-Derived Neurotrophic Factor
keywords: biomarker; brain-derived neurotrophic factor; deep brain stimulation; depression; subcallosal cingulate region