Time-dependent changes in non-COX-1-dependent platelet function with daily aspirin therapy
Published Date:Apr 2012
Source:J Thromb Thrombolysis. 33(3):246-257.
Pubmed Central ID:PMC3337886
Funding:5RC1GM091083/GM/NIGMS NIH HHS/United States
5T32HL007101/HL/NHLBI NIH HHS/United States
5U01DD000014-06/DD/NCBDD CDC HHS/United States
5UL1RR024128/RR/NCRR NIH HHS/United States
RC1 GM091083/GM/NIGMS NIH HHS/United States
RC1 GM091083-02/GM/NIGMS NIH HHS/United States
To develop an integrated metric of non COX-1 dependent platelet function (NCDPF) to measure the temporal response to aspirin in healthy volunteers and diabetics.
NCDPF on aspirin demonstrates wide variability, despite suppression of COX-1. Although a variety of NCDPF assays are available, no standard exists and their reproducibility is not established.
We administered 325mg/day aspirin to two cohorts of volunteers (HV1, n = 52, and HV2, n = 96) and diabetics (DM, n = 74) and measured NCDPF using epinephrine, collagen, and ADP aggregometry and PFA100 (collagen/epi) before (Pre), after one dose (Post), and after several weeks (Final). COX-1 activity was assessed with arachidonic acid aggregometry (AAA). The primary outcome of the study, the platelet function score (PFS), was derived from a principal components analysis of NCDPF measures.
The PFS strongly correlated with each measure of NCDPF in each cohort. After two or four weeks of daily aspirin the Final PFS strongly correlated (r > 0.7, p<0.0001) and was higher (p < 0.01) than the Post PFS. The magnitude and direction of the change in PFS (Final - Post) in an individual subject was moderately inversely proportional to the Post PFS in HV1 (r = −0.45), HV2 (r = −0.54), DM (r = −0.68), p<0.0001 for all. AAA remained suppressed during aspirin therapy.
The PFS summarizes multiple measures of NCDPF. Despite suppression of COX-1 activity, NCDPF during aspirin therapy is predictably dynamic: those with heightened NCDPF continue to decline whereas those with low/normal NCDPF return to pre-aspirin levels over time.
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