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: Hideaki Nakatsuji, Hironori Kobayashi, Ken Kishida, Tohru Nakagawa, Shigeo Takahashi, Hideaki Tanaka, Suguru Akamatsu, Tohru Funahashi, Iichiro Shimomura
• Journal: Metabolism: clinical and experimental (Metabolism) Vol. 62 Issue 1 Pg. 109-20 (Jan 2013) ISSN: 1532-8600 [Electronic] United States
• PMID: 22819529 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2013 Elsevier Inc. All rights reserved.

Chemical References

• Adiponectin
• Biomarkers
• Triglycerides
• Complement C1q
• Aspartate Aminotransferases
• Alanine Transaminase

Topics

• Adiponectin (blood)
• Adult
• Aged
• Alanine Transaminase (blood)
• Aspartate Aminotransferases (blood)
• Biomarkers (blood)
• Blotting, Western
• Complement C1q (metabolism)
• Humans
• Immunoprecipitation
• Intra-Abdominal Fat (metabolism)
• Male
• Metabolic Syndrome (blood, metabolism)
• Middle Aged
• ROC Curve
• Subcutaneous Fat (metabolism)
• Triglycerides (blood)