RT Journal Article
SR Electronic
T1 Plasminogen activators and their inhibitors in synovial fluids from normal, osteoarthritis, and rheumatoid arthritis knees.
JF Annals of the Rheumatic Diseases
JO Ann Rheum Dis
FD BMJ Publishing Group Ltd and European League Against Rheumatism
SP 230
OP 236
DO 10.1136/ard.55.4.230
VO 55
IS 4
A1 C Belcher
A1 F Fawthrop
A1 R Bunning
A1 M Doherty
YR 1996
UL http://ard.bmj.com/content/55/4/230.abstract
AB OBJECTIVES: To establish baseline concentrations of plasminogen activators and their inhibitors in normal knee synovial fluids, and to compare them with well characterised osteoarthritis (OA) and rheumatoid arthritis (RA) knee fluids. METHODS: A total of 26 normal subjects, 71 patients with OA, and 17 patients with RA underwent knee aspiration. Patients with OA were subclassified according to presence of nodal generalised OA (NGOA) and synovial fluid calcium pyrophosphate crystals. Clinical assessment of inflammation (graded 0-6) was undertaken in OA and RA patients. Plasminogen activator (PA), plasminogen activator inhibitor (PAI), and urokinase-type PA receptor (uPAR) antigen concentrations were determined by enzyme linked immunosorbent assay. The species of PAs present were determined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. RESULTS: Concentrations of all antigens (uPA, tissue-type PA (tPA), uPAR, and PAI-1), were significantly greater in RA than OA; those in OA were significantly greater than normal. The concentrations showed no direct association with clinically assessed inflammation of the knee. In normal fluids, no associations with age were observed. Antigen concentrations (uPA, tPA, and uPAR) in NGOA differed from those in other subclasses of OA, but the species of PA present did not appear to vary between disease groups. The predominant PA appeared to have identity with uPA. CONCLUSION: Because of the greater concentrations of these antigens in OA compared with normal fluids, OA cannot be used as a surrogate normal control in studies of the PA/PAI system. Alteration of the PA/PAI system was confirmed in RA and OA knee fluids, with greater changes evident in RA. The finding of different concentrations of PA antigens in NGOA compared with other OA fluids further supports a different pathogenic mechanism in this subset.