title: Unfavorably altered fibrin clot properties in patients with active rheumatoid arthritis.
abstract: OBJECTIVE
  Altered fibrin clot properties have been reported in cardiovascular diseases (CVD) and inflammatory states. Given increased prevalence of CVD in patients with rheumatoid arthritis (RA), we investigated whether fibrin characteristics are also altered in RA patients.
  
  
  METHODS
  We studied 46 consecutive RA patients versus 50 controls matched for age and gender. Ex vivo plasma clot permeability, turbidity, tissue-type plasminogen activator (tPA)-induced fibrinolysis, and scanning electron microscopy (SEM) images of clots were evaluated.
  
  
  RESULTS
  Patients with RA had lower clot permeability, faster clot formation, higher maximum clot absorbency indicating thicker fibrin fibers, maximum clot mass and prolonged fibrinolysis time than controls. Maximum rates of clot lysis were similar in both groups. SEM images showed formation of dense clots with many projections on fibrin fibers. Clot permeability inversely correlated with fibrinogen, tPA, plasminogen activator inhibitor-1 (PAI-1), CRP, platelet count, disease activity score (DAS28) and a marker of oxidative stress, 8-iso-prostaglandin F2alpha (r from -0.44 to -0.79; all, p<0.0001). Similar positive associations were found for clot lysis time (r 0.44 to 0.69; all, p<0.01). Multiple regression analysis showed that fibrinogen was the only independent predictor of clot permeability (R2=0.87, p<0.0001) and lysis time (R2=0.80, p<0.003) in RA. Maximum D-dimer levels released from clots, maximum clot turbidity and the time of clot formation were predicted by PAI-1 (all, p<0.05).
  
  
  CONCLUSIONS
  We showed unfavorably altered plasma fibrin clot structure and function in RA, which might contribute to an increased risk of thrombotic events in this disease.
authors.affiliation: Department of Rheumatology, Jagiellonian University School of Medicine, Krakow, Poland.
authors.forename: Beata
authors.initials: B
authors.lastname: Kwasny-Krochin
authors.forename: Piotr
authors.initials: P
authors.lastname: Gluszko
authors.forename: Anetta
authors.initials: A
authors.lastname: Undas
mesh_terms: D000328:Adult; D000368:Aged; D001780:Blood Coagulation Tests; D002318:Cardiovascular Diseases / Q000150:complications; D016022:Case-Control Studies; D005260:Female; D005337:Fibrin / Q000737:chemistry*; D005338:Fibrin Fibrinogen Degradation Products; D005340:Fibrinogen; D005342:Fibrinolysis; D006801:Humans; D007249:Inflammation / Q000150:complications; D008297:Male; D008875:Middle Aged; D010539:Permeability; D017395:Plasminogen Activator Inhibitor 1; D013927:Thrombosis / Q000097:blood / Q000209:etiology*; D010959:Tissue Plasminogen Activator; D055815:Young Adult
chemical_list: D005338:Fibrin Fibrinogen Degradation Products; D017395:Plasminogen Activator Inhibitor 1; C036309:fibrin fragment D; D005337:Fibrin; D005340:Fibrinogen; D010959:Tissue Plasminogen Activator