Interspecies differences in coagulation profile

Many animals are used in research on blood coagulation and fibrinolysis, but the relevance of animal models to human health is often questioned because of differences between species. The objective was to find an appropriate animal species, which mimics the coagulation profile in humans most adequately. Species differences in the coagulation profile with and without thrombin stimulation in vitro were assessed in whole blood by Rotation Thromboelastometry (ROTEM). Endogenous thrombin generation was measured in platelet-poor plasma. Measurements were performed in blood from five different species: humans, rats, pigs, sheep and rabbits. In humans and sheep, the clotting time (ROTEM) was in the same range with or without thrombin stimulation and a 100-fold lower dose of thrombin (0.002 IU) was required to cause a shortening in the clotting time as compared to rats, pigs and rabbits (0.2 IU) (p<0.05). Similarly, the endogenous thrombin potential (ETP) was in the same range in humans and sheep. The maximum clot firmness with or without thrombin stimulation was similar in rabbits and humans. The maximum lysis with or without thrombin stimulation was similar in humans and pigs. Significant species differences exist in the coagulation profile with or without thrombin stimulation. Most importantly, sheep had a clotting time most similar to humans and could thus be a suitable species for translational coagulation studies. Moreover, our findings confirm the potential usefulness of pigs as an experimental species to study fibrinolytic pathway and support the usefulness of rabbits as a species for examining platelets.