title: Longitudinal monitoring of the serotonin transporter gene expression to assess major depressive episode evolution.
abstract: BACKGROUND
  Mood disorders are frequently characterized by uncertain prognosis and studying mRNA expression variations in blood cells represents a promising avenue of identifying biomarkers for mood disorders. State-dependent gene expression variations have been described during a major depressive episode (MDE), in particular for SLC6A4 mRNA, but how this transcript varies in relation to MDE evolution remains unclear. In this study, we prospectively assessed time trends of SCL6A4 mRNA expression in responder and nonresponder patients.
  
  
  METHODS
  We examined SLC6A4 mRNA expression in blood samples from 13 patients treated for severe MDE and their matched controls by reverse transcription and quantitative PCR. All subjects were followed for 30 weeks. Patients were classified as either responders or nonresponders based on improvement of depression according to the 17-item Hamilton Depression Rating Scale. Using a longitudinal design, we ascertained mRNA expression at baseline, 2, 8, and 30 weeks and compared mRNA expression between responder and nonresponder patients, and matched controls.
  
  
  RESULTS
  We observed a decrease of SLC6A4 mRNA expression in responder patients across a 30-week follow-up, while nonresponder patients exhibited up-regulated SLC6A4 mRNA.
  
  
  CONCLUSIONS
  Peripheral SLC6A4 mRNA expression could serve as a biomarker for monitoring and follow-up during an MDE and may help to more appropriately select individualized treatments.
authors.affiliation: Aix-Marseille Université, CNRS, CRN2M UMR 7286, Marseille, France.
authors.forename: Raoul
authors.initials: R
authors.lastname: Belzeaux
authors.forename: Anderson
authors.initials: A
authors.lastname: Loundou
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Azorin
authors.forename: Jean
authors.initials: J
authors.lastname: Naudin
authors.forename: El Chérif
authors.initials: EC
authors.lastname: Ibrahim
mesh_terms: D000328:Adult; D000368:Aged; D000928:Antidepressive Agents / Q000627:therapeutic use; D015415:Biomarkers / Q000097:blood; D003865:Major Depressive Disorder / Q000097:blood / Q000188:drug therapy / Q000235:genetics*; D005260:Female; D015870:Gene Expression; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000097:blood; D050486:Serotonin Plasma Membrane Transport Proteins / Q000097:blood / Q000235:genetics*; D016896:Treatment Outcome
chemical_list: D000928:Antidepressive Agents; D015415:Biomarkers; D012333:RNA, Messenger; C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins