title: Fatty acid binding protein 3 is associated with skeletal muscle strength in polymyositis and dermatomyositis.
abstract: OBJECTIVE
  To determine serum levels and histopathological characteristics of fatty acid binding protein 3 (FABP3) in patients with polymyositis (PM) and dermatomyositis (DM), and to evaluate the correlation between the FABP3 and muscle strength.
  
  
  METHODS
  The study population included 24 subjects with PM/DM, 12 subjects with asymptomatic or minimally symptomatic hyper-creatine kinase-emia (AMSH), and 10 healthy control subjects. Muscle strength was measured by using the Manual Muscle Test (MMT8). Serum CK, myoglobin and FABP3 levels were tested. Correlations between variables were studied by using Spearman's rank and partial correlation analysis methods. Immunohistochemical and double immunofluorescent stainings of FABP3 were performed to investigate its distribution in skeletal muscle.
  
  
  RESULTS
  PM/DM patients had significantly higher (P < 0.05) serum FABP3 levels (35.46 ± 38.45 ng/mL) than did AMSH patients (3.77 ± 1.21 ng/mL) and healthy control subjects (4.30 ± 3.18 ng/mL). MMT8 scores correlated negatively with CK, myoglobin and FABP3 levels. Partial correlation analysis was performed and showed that the correlation coefficients between MMT8 score and serum CK, myoglobin and FABP3 levels were -0.276 (P > 0.05), -0.228 (P > 0.05) and -0.927 (P < 0.001), respectively. Immunohistochemical and double immunofluorescent staining showed that FABP3 expression increased in the skeletal muscle of PM/DM patients and was mainly distributed in slow twitch muscle fibers.
  
  
  CONCLUSIONS
  Serum levels of FABP3 in PM/DM patients were significantly increased and were mainly distributed in slow twitch muscle fibers, displaying a closer association with muscle weakness than did serum levels of CK and myoglobin. FABP3 is likely to be a useful serum biomarker in PM/DM patients.
authors.affiliation: Department of Rheumatology, China-Japan Friendship Hospital, Beijing, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Rheumatology, Beijing Friendship Hospital Capital Medical University, Beijing, China.
authors.forename: Hang
authors.initials: H
authors.lastname: Zhou
authors.affiliation: Department of Rheumatology, China-Japan Friendship Hospital, Beijing, China.
authors.forename: Qinglin
authors.initials: Q
authors.lastname: Peng
authors.affiliation: Department of Rheumatology, China-Japan Friendship Hospital, Beijing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Jiang
authors.affiliation: Department of Senior Ward, China-Japan Friendship Hospital, Beijing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Qiao
authors.affiliation: Department of Rheumatology, China-Japan Friendship Hospital, Beijing, China.
authors.forename: Guochun
authors.initials: G
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D052283:Creatine Kinase, MM Form / Q000097:blood; D003882:Dermatomyositis / Q000097:blood* / Q000175:diagnosis / Q000503:physiopathology*; D000074026:Fatty Acid Binding Protein 3 / Q000097:blood*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D018656:Muscle Fibers, Fast-Twitch / Q000737:chemistry; D018657:Muscle Fibers, Slow-Twitch / Q000737:chemistry; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000737:chemistry* / Q000503:physiopathology*; D009211:Myoglobin / Q000097:blood; D015854:Up-Regulation; D055815:Young Adult
chemical_list: D015415:Biomarkers; C493408:FABP3 protein, human; D000074026:Fatty Acid Binding Protein 3; D009211:Myoglobin; D052283:Creatine Kinase, MM Form
keywords: dermatomyositis; fatty acid-binding protein 3; muscle strength; polymyositis