MDA Production in Human Platelets Subpopulations after a Single Intake of Aspirin, A Kinetic Study

Kinetics of platelet of various densities was studied using the MDA method. MDA nroduc-tion was stimulated by arachidonic acid (500/μM) and was measured on each four isolated Subpopulation according to Corash. The following points were checked : PRP preparation procedures do not exclude a platelet subpopulatioti with different characteristics of volumes and densities ; MDA production is equivalent whatever the platelet densities ; the reproducibility of the platelet separation into the four subpopulations is good (CV : 5 -10%) After a single intake of 0.50 g of aspirin (with 3 different volunteers) the following results are observed : (1) Between day 1 and 7 the curves of the WA reappearance in the four subpopulations are divergent. (2) On the seventh day, the MDA recovery in light platelets is near 90% but only 50% in the dense ones. (3) Between day 7 and 12, the MDA level in the dense platelets reaches the level of light platelets. These data suogest the two following hypotheses. (A) Young platelets are heterogeneous but mainly light ; during the first days of their life span, they nresent an increase in their density (analoqy with the erythrocytes), (B) The comparison of these results witn those of Corash (Blood, 1378, 52, 726) may suggest that light platelets would present a shorter turn over than heavy platelets.