Platelet function in brown bear (Ursus arctos) compared to man
1 Department of Cardiology, Örebro University Hospital, Sweden
2 Department of Clinical Sciences, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, Uppsala, Sweden
3 Department of Veterinary Clinical and Diagnostic Sciences, Faculty of Veterinary Medicine, University of Calgary, Calgary, Canada
4 The Scandinavian Brown Bear Research Project, Tackåsen, Orsa, Sweden
5 Department of Clinical Medicine, School of Health and Medical Sciences, Örebro University, Sweden
6 Department of Ecology and Natural Resources Management, Norwegian University of Life Sciences, Ǻs, Norway. and Norwegian Institute for Nature Research, Trondheim, Norway
7 Department of Wildlife, Fish and Environmental Studies, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Umeå, Sweden
8 Faculty of Forestry and Wildlife Management, Hedmark University College, Campus Evenstad, Norway
Thrombosis Journal 2010, 8:11 doi:10.1186/1477-9560-8-11Published: 2 June 2010
Information on hemostasis and platelet function in brown bear (Ursus arctos) is of importance for understanding the physiological, protective changes during hibernation.
The study objective was to document platelet activity values in brown bears shortly after leaving the den and compare them to platelet function in healthy humans.
Blood was drawn from immobilized wild brown bears 7-10 days after leaving the den in mid April. Blood samples from healthy human adults before and after clopidogrel and acetylsalicylic acid administration served as control. We analyzed blood samples by standard blood testing and platelet aggregation was quantified after stimulation with various agonists using multiple electrode aggregometry within 3 hours of sampling.
Blood samples were collected from 6 bears (3 females) between 1 and 16 years old and from 10 healthy humans. Results of adenosine diphosphate, aspirin, and thrombin receptor activating peptide tests in bears were all half or less of those in humans. Platelet and white blood cell counts did not differ between species but brown bears had more and smaller red blood cells compared with humans.
Using three different tests, we conclude that platelet function is lower in brown bears compared to humans. Our findings represent the first descriptive study on platelet function in brown bears and may contribute to explain how bears can endure denning without obvious thrombus building. However, the possibility that our findings reflect test-dependent and not true biological variations in platelet reactivity needs further studies.