Whole blood platelet aggregation in humans and animals: A comparative study

Background. Many animal species are used to evaluate the performance and bl ood compatibility of cardiovascular devices, but interspecies differences i n platelet activity have not been well characterized. This study measures p latelet response to six agonists in human, dog, and calf blood. Materials and methods. We used whole blood impedance lumi-aggregometry to m easure platelet aggregation and ATP release in blood samples from adult hum ans (n = 19), mongrel dogs (n = 19), and Holstein calves (n = 7). The agoni sts were collagen, ristocetin, arachidonic acid, thrombin, and three concen trations of both ADP and epinephrine. Results. Only collagen (1 mu g/ml) and ADP (5, 10, and 20 mu M) caused aggr egation and ATP release in all samples. Canine platelets responded to all s ix agonists at all doses. Human platelets responded to everything except ep inephrine at 2 and 100 mu M. Bovine platelets responded only to collagen, A DP, and thrombin. In bovine platelets, aggregation from collagen and ATP re lease from thrombin were significantly lower than the corresponding respons es in human and canine blood. The aggregation induced by 10 mu M ADP was si gnificantly higher in canine than in human platelets. Conclusion, Human, canine, and bovine platelets have very different respons es to agonists. In these models, collagen (1 mu g/ml) and ADP (10 mu M) are the agonists of choice for investigating whole blood platelet aggregation because they provide the most consistent results between species. For ATP r elease, 1 U/ml thrombin is the recommended agonist and the dose for all thr ee species, (C) 1999 Academic Press.