title: Proteomic analysis of serum from patients with major depressive disorder to compare their depressive and remission statuses.
abstract: OBJECTIVE
  Currently, there are a few biological markers to aid in the diagnosis and treatment of depression. However, it is not sufficient for diagnosis. We attempted to identify differentially expressed proteins during depressive moods as putative diagnostic biomarkers by using quantitative proteomic analysis of serum.
  
  
  METHODS
  Blood samples were collected twice from five patients with major depressive disorder (MDD) at depressive status before treatment and at remission status during treatment. Samples were individually analyzed by liquid chromatography-tandem mass spectrometry for protein profiling. Differentially expressed proteins were analyzed by label-free quantification. Enzyme-linked immunosorbent assay (ELISA) results and receiver-operating characteristic (ROC) curves were used to validate the differentially expressed proteins. For validation, 8 patients with MDD including 3 additional patients and 8 matched normal controls were analyzed.
  
  
  RESULTS
  The quantitative proteomic studies identified 10 proteins that were consistently upregulated or downregulated in 5 MDD patients. ELISA yielded results consistent with the proteomic analysis for 3 proteins. Expression levels were significantly different between normal controls and MDD patients. The 3 proteins were ceruloplasmin, inter-alpha-trypsin inhibitor heavy chain H4 and complement component 1qC, which were upregulated during the depressive status. The depressive status could be distinguished from the euthymic status from the ROC curves for these proteins, and this discrimination was enhanced when all 3 proteins were analyzed together.
  
  
  CONCLUSIONS
  This is the first proteomic study in MDD patients to compare intra-individual differences dependent on mood. This technique could be a useful approach to identify MDD biomarkers, but requires additional proteomic studies for validation.
authors: Department of Senior Healthcare, BK21 Plus Program, Graduate School, Eulji University, Daejeon, Republic of Korea.
authors: Jiyeong
authors: J
authors: Lee
authors: Department of Neuropsychiatry, School of Medicine, Eulji University, Daejeon, Republic of Korea.
authors: Eun-Jeong
authors: EJ
authors: Joo
authors: Laboratory of Stem Cell Biology, Division of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea.
authors: Hee-Joung
authors: HJ
authors: Lim
authors: College of Pharmacy, Gachon University, Incheon, Republic of Korea.
authors: Jong-Moon
authors: JM
authors: Park
authors: Department of Neuropsychiatry, School of Medicine, Eulji University, Daejeon, Republic of Korea.
authors: Kyu Young
authors: KY
authors: Lee
authors: Department of Senior Healthcare, BK21 Plus Program, Graduate School, Eulji University, Daejeon, Republic of Korea.
authors: Arum
authors: A
authors: Park
authors: Department of Senior Healthcare, BK21 Plus Program, Graduate School, Eulji University, Daejeon, Republic of Korea.
authors: AeEun
authors: A
authors: Seok
authors: College of Pharmacy, Gachon University, Incheon, Republic of Korea.
authors: HooKeun
authors: H
authors: Lee
authors: Department of Senior Healthcare, BK21 Plus Program, Graduate School, Eulji University, Daejeon, Republic of Korea. ; Institute for Senior Industry, Eulji University, Seongnam, Republic of Korea. ; Department of Biomedical Laboratory Science, Graduate School of Health Science, Eulji University, Seongnam, Republic of Korea.
authors: Hee-Gyoo
authors: HG
authors: Kang
keywords: Biomarker; Inflammation; Major depressive disorder; Neurotransmitter; Proteomics