Mini-plasminogen-like fragments of plasminogen in synovial fluid in acute inflammatory arthritis.
Neutrophil elastase digests plasminogen to yield a fragment, mini-plasminogen, which is activatable to a mini-plasmin capable of escaping the action of the primary plasmin inhibitor. Such a molecule may play a role in joint destruction, either directly or by activation of procollagenase to collagenase. Synovial fluid samples from 34 acute joint effusions were examined by lysine-Sepharose chromatography and fibrinolytic assay of the fall-through (non-lysine-binding) fractions in presence of urokinase. Fragments similar to mini-plasminogen were found in 20 of 23 inflammatory effusions (cell count greater than 0.5 X 10(3)/microliter) and in none of 11 non-inflammatory (traumatic and osteoarthritic) effusions (cell count less than 0.5 X 10(3)/microliter) (p less than 0.001). Analysis of four inflammatory fluids by gel filtration on Bio-Gel P 100 and enzyme-linked immunoassay for plasminogen antigen revealed plasminogen fragments with molecular weight similar to mini-plasminogen (34,000 daltons) in three, and larger plasminogen fragments (or complexes of mini-plasminogen with other synovial fluid macromolecules) in all four. Fibrinolytic activity was demonstrable in fractions containing plasminogen fragments after treatment with tissue type plasminogen activator. In contrast with non-inflammatory effusions, inflammatory joint fluids contain plasminogen fragments with the properties of mini-plasminogen, suggesting their possible role in inflammatory joint destruction.
D000208:Acute Disease; D001172:Arthritis, Rheumatoid / Q000378:metabolism*; D002850:Chromatography, Gel; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007249:Inflammation; D009504:Neutrophils / Q000201:enzymology; D010196:Pancreatic Elastase / Q000097:blood; D010446:Peptide Fragments / Q000032:analysis*; D010958:Plasminogen / Q000032:analysis*; D013582:Synovial Fluid / Q000032:analysis*
D010446:Peptide Fragments; D010958:Plasminogen; D010196:Pancreatic Elastase