Background: Platelets play an important role in inflammation and are activa
ted in inflammatory bowel disease, Micro-vascular thrombosis in the gut wal
l leading to intestinal micro-infarction may be a pathogenic feature of Cro
hn's disease. 5-Aminosalicylic acid is an effective treatment for patients
with inflammatory bowel disease.
Aims: To assess the effects of 5-aminosalicylic acid on platelet activation
, when taken orally and in vitro by patients with inflammatory bowel diseas
e. Methods: Spontaneous and thrombin-induced platelet activation were studi
ed using fluorescent antibodies to the activated platelet surface glycoprot
ein P-selectin and flow cytometry.
Results: Baseline platelet activation in inflammatory bowel disease was sig
nificantly greater than that in controls (P = 0.0003). Independent of diagn
osis or disease activity, spontaneous ex-vivo platelet activation was 50% l
ower in patients with inflammatory bowel disease taking 5-aminosalicylic ac
id orally than in those not on such treatment (P < 0.05), In vitro, 5-amino
salicylic acid significantly reduced both spontaneous (P < 0.03 for > 1 mu
M 5-aminosalicylic acid) and thrombin-induced platelet activation (P < 0.02
for greater than or equal to 1 mu M 5-aminosalicylic acid).
Conclusions: 5-Aminosalicylic acid given either orally or in vitro inhibits
platelet activation. If this effect reflects an in vivo action in the gut,
it could contribute to the beneficial actions of 5-aminosalicylic acid in
inflammatory bowel disease.