Insulin-like growth factor I and its binding proteins 3 and 4 are increased in Human inflammatory synovial fluid.
OBJECTIVE
To measure insulin-like growth factor I (IGF-I) and its binding proteins (IGFBP) in human synovial fluid (SF), as IGF-I resistance in the chondrocyte was implicated in the pathogenesis of inflammatory arthritis.


METHODS
Ten patients with inflammatory arthritis and 7 controls were evaluated. IGF-I and IGFBP-3 were measured by radioimmunoassay while all IGFBP were evaluated by Western ligand blotting.


RESULTS
Serum IGF-I did not differ between patients and controls (22.3 +/- 2.9 vs 22.0 +/- 3.0 nmol/l), while significantly higher values were found in inflammatory SF compared with noninflammatory SF (14.7 +/- 1.5 vs 10.2 +/- 1.2 nmol/l; p = 0.05). IGFBP-3 and IGFBP-4 were the most prominent bands found in inflammatory SF by Western ligand blotting. The 24 kDa IGFBP-4 band appeared faintly in 2 noninflammatory effusions and was nearly absent in others. IGFBP-3 levels in sera from the 2 groups did not differ (2.9 +/- 0.3 vs 2.5 +/- 0.3 mg/l), but were significantly higher in inflammatory compared with noninflammatory effusions (1.5 +/- 0.2 vs 0.9 +/- 0.2 mg/l; p = 0.05).


CONCLUSIONS
The pattern of IGFBP in SF differs in inflammatory versus noninflammatory joints.
Kanety
H
H
Department of Internal Medicine, Chaim Sheba Medical Center, Tel-Hashomer, Israel.
Shimon
I
I
Ehrenfeld
M
M
Israeli
A
A
Pariente
C
C
Karasik
A
A
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001170:Arthritis, Infectious / Q000378:metabolism*; D015153:Blotting, Western; D005260:Female; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000032:analysis* / Q000097:blood; D018974:Insulin-Like Growth Factor Binding Protein 4 / Q000032:analysis* / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D013582:Synovial Fluid / Q000737:chemistry*
D018972:Insulin-Like Growth Factor Binding Protein 3; D018974:Insulin-Like Growth Factor Binding Protein 4; D007334:Insulin-Like Growth Factor I