Release of cartilage and bone macromolecules into synovial fluid: differences between psoriatic arthritis and rheumatoid arthritis.

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Ann Rheum Dis 2001 Jan;60(1):27-31

Release of cartilage and bone macromolecules into synovial fluid: differences

between psoriatic arthritis and rheumatoid arthritis.

Mansson B, Gulfe A, Geborek P, Heinegard D, Saxne T

Department of Rheumatology, Lund University, Lund, Sweden.

[Record supplied by publisher]

OBJECTIVE: To elucidate whether differences in the destructive tissue process in

cartilage and bone in psoriatic arthritis (PsA) and rheumatoid arthritis (RA)

can be recognised by different release patterns of molecular fragments derived

from joint tissue. METHODS: Aggrecan, cartilage oligomeric matrix protein

(COMP), and bone sialoprotein (BSP) were quantified by immunoassays in knee

joint synovial fluid samples. These were obtained early in the disease course of

patients with PsA and RA. At the time of arthrocentesis radiographs of their

knee and hip joints were normal. RESULTS: At follow up no destruction had

developed in the knees and hips of most patients with PsA (n=18), whereas the

patients with RA could be separated into one " destructive " group (n=18) and one

" non-destructive " group (n=25). Patients with PsA had low synovial fluid

aggrecan concentrations (p<0.001 v the RA destructive group) but high COMP

concentrations (p<0.01 and p<0.05 v destructive and non-destructive RA groups,

respectively). Consequently, the aggrecan/COMP ratio was lowest in the PsA group

(p<0.001 and p<0.01 v the destructive and non-destructive RA group,

respectively). The synovial fluid concentrations of BSP did not differ between

the three patient groups. CONCLUSIONS: The release pattern of aggrecan and COMP,

reflecting cartilage turnover, differed between the PsA group and, particularly,

the destructive RA group. This suggests that different pathophysiological

mechanisms for cartilage involvement operate in these conditions, with different

destructive potential. The BSP concentrations did not differ between the

patients groups, which indicates similar levels of bone involvement.

PMID: 11114278