Increased aggregation response of platelets in patients with inflammatory bowel disease.
BACKGROUND
Platelets play an important role in hemostatic and inflammatory responses. To evaluate any potential enhancement of platelet activity in patients with inflammatory bowel disease (IBD), we measured the platelet aggregation responses to various stimuli.


METHODS
Twenty-two healthy controls, 24 patients with ulcerative colitis (UC) and 25 patients with Crohn's Disease (CD) were studied. The aggregation responses induced by three agonists (epinephrine, collagen, and ADP) were measured by an 8-channel aggregometer. The platelet-derived microparticles (PDMP) levels were measured by an enzyme-linked immunosorbent assay.


RESULTS
Twenty-one out of the 22 healthy controls did not respond to epinephrine (0.1 microg/ml), collagen (0.2 microg/ml), or ADP (1.0 microM). Eight out of the 12 active UC patients were sensitive to all agonists, and 4 patients showed increased sensitivity to epinephrine/collagen or epinephrine/ADP. Three out of the 12 inactive UC patients were normal, but 9 of these patients showed increased sensitivity, mainly to epinephrine. Ten out of the 12 active CD patients were sensitive to all agonists, and 2 active CD patients were sensitive to epinephrine/collagen or epinephrine/ADP. Eight out of the 13 inactive CD patients were sensitive to two or all agonists. Even after remission, almost all of the UC and CD patients showed some increased sensitivity to the agonists. The platelet number and the plasma PDMP levels were significantly higher in the active IBD patients than in the control group.


CONCLUSIONS
Platelet aggregation responses are enhanced in IBD, even in inactive-phase patients. This increased sensitivity of the platelets may play an important role in the pathophysiology of IBD.
Andoh
Akira
A
Department of Internal Medicine, Shiga University of Medical Science, Seta-Tsukinowa, Otsu, 520-2192, Japan.
Yoshida
Takashi
T
Yagi
Yuki
Y
Bamba
Shigeki
S
Hata
Kazunori
K
Tsujikawa
Tomoyuki
T
Kitoh
Katsuyuki
K
Sasaki
Masaya
M
Fujiyama
Yoshihide
Y
D000244:Adenosine Diphosphate / Q000494:pharmacology; D000328:Adult; D001777:Blood Coagulation / Q000502:physiology; D003094:Collagen / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D004837:Epinephrine / Q000494:pharmacology; D005260:Female; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000097:blood*; D008297:Male; D010974:Platelet Aggregation / Q000187:drug effects / Q000502:physiology*; D012720:Severity of Illness Index
D000244:Adenosine Diphosphate; D003094:Collagen; D004837:Epinephrine