Platelet reactivity: a contribution to age dependence studies

The authors examined 230 healthy donors (20-90 years) as to basic biochemical and haematological parameters and those parameters characterizing the function of blood platelets. Besides well known age dependences of fibrinogen concentration, AT III, erythrocyte sedimentation, glucose, cholesterol, alpha-2-macroglobulin and circulating immunocomplexes the results are presented showing a pronounced dependence of primary haemostatic system upon age. Within the age groups 65-75 years and those above 75 years there was a significantly higher amount of circulating aggregates (increase up to 152%), elevated concentration of beta-thromboglobulin and F VIII R:Ag. The increased reactivity of platelets is detectable even by applying relatively simple tests such as the determination of heparin-neutralizing activity, aggregation response to lower concentrations of induces or the determination of the amount of circulating aggregates.