title: Binding of adiponectin and C1q in human serum, and clinical significance of the measurement of C1q-adiponectin / total adiponectin ratio.
abstract: OBJECTIVE
  Adiponectin and C1q have similar sequences, exist abundantly in blood, and are produced by adipose tissues. The aim of this study was to examine whether adiponectin and C1q form protein-complex in blood and to know the clinical significance of the C1q-adiponectin (C1q-APN) complex in serum.
  
  
  METHODS
  The direct interaction between adiponectin and C1q was investigated by far western blotting and co-immunoprecipitation. The relationship between serum C1q-APN and various clinical features was analyzed in 329 Japanese men who underwent health check-up, including measurements of visceral (VFA) and subcutaneous fat area (SFA) by computed tomography (Victor-J study).
  
  
  RESULTS
  Adiponectin bound to C1q in vitro and C1q-APN complex existed in human blood. C1q-APN complexes were identified in high- and middle-molecular weight forms of adiponectin in human serum by gel-filtration chromatography. Stepwise multiple regression analysis identified body mass index, VFA and SFA as significant determinants of serum C1q-APN level. Serum C1q-APN/Total-APN ratio correlated positively with cardiovascular risk factor accumulation in subjects with VFA ≥100 cm(2).
  
  
  CONCLUSIONS
  These results indicate that high- and middle-molecular forms of adiponectin partly consist of adiponectin-complex with other proteins including C1q and that the blood C1q-APN/Total-APN ratio may serve as a biomarker of the metabolic syndrome in general male subjects.
authors: Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan.
authors: Hideaki
authors: H
authors: Nakatsuji
authors: Hironori
authors: H
authors: Kobayashi
authors: Ken
authors: K
authors: Kishida
authors: Tohru
authors: T
authors: Nakagawa
authors: Shigeo
authors: S
authors: Takahashi
authors: Hideaki
authors: H
authors: Tanaka
authors: Suguru
authors: S
authors: Akamatsu
authors: Tohru
authors: T
authors: Funahashi
authors: Iichiro
authors: I
authors: Shimomura
mesh_terms: D052242:Adiponectin / Q000097:blood*; D000328:Adult; D000368:Aged; D000410:Alanine Transaminase / Q000097:blood; D001219:Aspartate Aminotransferases / Q000097:blood; D015415:Biomarkers / Q000097:blood; D015153:Blotting, Western; D015922:Complement C1q / Q000378:metabolism*; D006801:Humans; D047468:Immunoprecipitation; D050152:Intra-Abdominal Fat / Q000378:metabolism; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood* / Q000378:metabolism; D008875:Middle Aged; D012372:ROC Curve; D050151:Subcutaneous Fat / Q000378:metabolism; D014280:Triglycerides / Q000097:blood
chemical_list: D052242:Adiponectin; D015415:Biomarkers; D014280:Triglycerides; D015922:Complement C1q; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase