title: Serum complement C3f and fibrinopeptide A are potential novel diagnostic biomarkers for non-alcoholic fatty liver disease: a study in Qingdao Twins.
abstract: OBJECTIVE
  To compare the different serum peptidome patterns between twins with and without non-alcoholic fatty liver disease (NAFLD) in order to help understand the pathogenesis of NAFLD and to identify potential diagnostic and therapeutic targets.
  
  
  METHODS
  The peptidomics patterns of 63 cases with NAFLD were compared with their twin healthy controls in Qingdao, China. Peptides between 800 Da and 3,500 Da were captured and concentrated using C18 reversed-phase columns, followed by MALDI-TOF mass spectrometry. The sequences of peptides associated with NAFLD were further identified by MALDI-TOF-TOF. Further validation studies were conducted. One hundred additional serum samples were detected by commercially available ELISA kits to calculate the concentrations of complement C3f and fibrinopeptide A, respectively. The differences of these two peptides in the NAFLD and control groups were compared using SPSS 17.0, respectively.
  
  
  RESULTS
  Compared with healthy controls, eleven peaks (861.1, 877.07, 904.5, 1206.57, 1350.64, 1518.7, 1690.9, 1777.94, 2931.29, 3190.4, 3261.4) were up-regulated and 7 peaks (942.44, 1020.47, 1060.06, 1211.7, 1263.63, 1449.76, 2768.3) were down-regulated in the NAFLD group. Two peptides derived from complement C3f and fibrinopeptide A, respectively, had the highest ROC values indistinguishing NAFLD cases from their normal controls. In the validation group, the concentrations of complement C3f and fibrinopeptide A (1466.929 ± 78.306 pg/ml, 4.189 ± 0.326 ng/ml, respevtively) in NAFLD group was higher than in control group (complement C3f 1159.357 ± 99.624 pg/ml, FPA 3.039 ± 0.483 ng/ml; P<0.05).
  
  
  CONCLUSIONS
  In this study, we established apeptidomics pattern that could help distinguish NAFLD patients from their twin controls. The differently-regulated peptides identified in our study may be potential diagnostic markers or therapeutic targets for NAFLD.
authors.affiliation: Qingdao Municipal Hospital, Qingdao, Shandong Province, PR China.
authors.forename: Yong-Ning
authors.initials: YN
authors.lastname: Xin
authors.affiliation: School of Medicine, Qingdao University, Qingdao, Shandong Province, PR China.
authors.forename: Ning
authors.initials: N
authors.lastname: Geng
authors.affiliation: Qingdao Municipal Hospital, Qingdao, Shandong Province, PR China.
authors.forename: Zhong-Hua
authors.initials: ZH
authors.lastname: Lin
authors.affiliation: Key Laboratory of Ministry of Health for Biotech-Drug, Key Laboratory for Modern Medicine and Technology of Shandong Province, Shandong Medicinal Biotechnology Center, Shandong Academy of Medical Sciences, Jinan, PR China.
authors.forename: Ya-Zhou
authors.initials: YZ
authors.lastname: Cui
authors.affiliation: Qingdao Municipal Centers for Disease Control and Prevention, Qingdao, Shandong Province, PR China.
authors.forename: Hai-Ping
authors.initials: HP
authors.lastname: Duan
authors.affiliation: Qingdao Municipal Hospital, Qingdao, Shandong Province, PR China.
authors.forename: Mei
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Qingdao Municipal Hospital, Qingdao, Shandong Province, PR China.
authors.forename: Shi-Ying
authors.initials: SY
authors.lastname: Xuan
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000032:analysis / Q000097:blood*; D002681:China / Q000453:epidemiology; D003179:Complement C3b / Q000032:analysis*; D005260:Female; D005344:Fibrinopeptide A / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D065626:Non-alcoholic Fatty Liver Disease / Q000097:blood* / Q000175:diagnosis* / Q000453:epidemiology; D014427:Twins
chemical_list: D015415:Biomarkers; C046821:complement C3f; D005344:Fibrinopeptide A; D003179:Complement C3b