Schmid W, Vogelsang H, Papay P, Primas C, Eser A, Gratzer C, Handler M, Novacek G, Panzer S. Increased responsiveness to thrombin through protease-activated receptors (PAR)-1 and -4 in active Crohn's disease.
J Crohns Colitis 2014;
8:495-503. [PMID:
24291018 DOI:
10.1016/j.crohns.2013.11.001]
[Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Revised: 10/03/2013] [Accepted: 11/02/2013] [Indexed: 02/08/2023]
Abstract
BACKGROUND AND AIMS
Platelets are essential in hemostasis and inflammation, thereby linking coagulation with inflammation. Abundant thrombin generation in association with inflammation is considered a major reason for the increased risk for thromboembolic events. We therefore investigated platelet responsiveness to thrombin.
METHODS
In this case-control study 85 patients with Crohn's disease (active CD 42, remission 43) and 30 sex- and age-matched controls were enrolled. Clinical disease activity (Harvey-Bradshaw-Index) was assessed and CD-related data were determined by chart review. Platelets' response to protease activated receptor-1 and -4 (PAR-1, -4) was assessed by whole blood platelet aggregometry (MEA), levels of platelets adhering to monocytes (PMA), and platelet surface P-selectin.
RESULTS
Platelets' aggregation after activation with the specific PAR-1 agonist (SFLLRN) and PAR-4 agonist (AYPGKF) was higher in patients with active CD compared to patients in remission and controls (p=0.0068 and p=0.0023 for SFLLRN, p=0.0019 and 0.0003 for AYPGKF). Likewise, levels of PMA after activation with PAR-1 and PAR-4 receptor agonists were higher in patients with active CD compared to patients in remission and controls (p=0.0001 and p<0.0001 for SFLLRN, p=0.0329 and p=0.0125 for AYPGKF). However, P-selectin expression on human platelets showed heterogeneous results. Only PAR-1 activation of platelets resulted in significant differences between CD patients and controls (p=0.0001 and p=0.0022 for active and inactive CD versus controls, respectively).
CONCLUSIONS
Our data suggest a new mechanism of platelet activation which has the potential to increase risk for thromboembolism in patients with active CD which might be due to platelets poised for thrombin-inducible activation.
Collapse