title: Platelets circulate in an activated state in inflammatory bowel disease.
abstract: OBJECTIVE
  Platelets show proinflammatory as well as prothrombotic properties. Patients with inflammatory bowel disease are at increased risk of systemic thromboembolism, and multifocal microvascular infarction has been proposed as a pathogenetic mechanism in Crohn's disease. The aim of this study was to determine if inflammatory bowel disease is associated with abnormal platelet behavior.
  
  
  METHODS
  Platelet activation and aggregability were assessed using flow cytometry, Born aggregometry, and the modified method of Wu and Hoak. Serum beta-thromboglobulin was measured in patients with Crohn's disease and ulcerative colitis and, as controls, in healthy volunteers and patients with active rheumatoid arthritis.
  
  
  RESULTS
  Platelet surface expression of P-selectin and GP53 (markers of activation) were increased in Crohn's disease (13 of 30 patients abnormal for P-selectin; 9 of 28 abnormal for GP53) (P < 0.01) and ulcerative colitis (9 of 21 for P-selectin; 10 of 21 for GP53) (P < 0.01) compared with healthy controls. Increased circulating platelet aggregates (15 of 24 patients with Crohn's disease and 8 of 16 with ulcerative colitis) (P < 0.01), platelet aggregability in vitro, and serum beta-thromboglobulin were detected in active inflammatory bowel disease compared with healthy controls. Platelet behavior in active rheumatoid arthritis resembled that in healthy controls.
  
  
  CONCLUSIONS
  Increased platelet activation and aggregation are features of inflammatory bowel disease and may contribute to the risk of systemic thromboembolism and the pathogenesis of mucosal inflammation. Therefore, antiplatelet agents may be valuable in the management of inflammatory bowel disease.
authors.affiliation: Gastrointestinal Science Research Unit, London Hospital Medical College, Whitechapel, England.
authors.forename: C E
authors.initials: CE
authors.lastname: Collins
authors.forename: M R
authors.initials: MR
authors.lastname: Cahill
authors.forename: A C
authors.initials: AC
authors.lastname: Newland
authors.forename: D S
authors.initials: DS
authors.lastname: Rampton
mesh_terms: D000328:Adult; D001792:Blood Platelets / Q000502:physiology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000097:blood*; D008297:Male; D008875:Middle Aged; D015539:Platelet Activation; D010974:Platelet Aggregation; D012016:Reference Values