Abstract

During six months of annual hibernation, the brown bear undergoes unique physiological changes to adapt to decreased metabolic rate. We compared cardiac structural and functional measures of hibernating and active bears using comprehensive echocardiography. We performed echocardiography on 13 subadult free-ranging, anaesthetised Scandinavian brown bears (Ursus arctos) during late hibernation and in early summer. Mean heart rate was 26 beats per minute (standard deviation (SD): 8) during hibernation vs 71 (SD: 14) during active state. All left ventricular (LV) systolic and diastolic measures were decreased during hibernation: mean ejection fraction: 44.2% (SD: 6.0) active state vs 34.0 (SD: 8.1) hibernation, P = 0.001; global longitudinal strain: −11.2% (SD: 2.0) vs −8.8 (SD: 3.3), P = 0.03; global longitudinal strain rate: −0.82 (SD: 0.15) vs −0.41 (SD: 0.18), P < 0.001; septal e’: 9.8 cm/s (SD: 1.8) vs 5.2 (SD: 2.7), P < 0.001. In general, measures of total myocardial motion (ejection fraction and global longitudinal strain) were decreased to a lesser extent than measures of myocardial velocities. In the hibernating brown bear, cardiac adaptation included decreased functional measures, primarily measures of myocardial velocities, but was not associated with cardiac atrophy. Understanding the mechanisms of these adaptations could provide pathophysiological insight of human pathological conditions such as heart failure.

Details

Title
Cardiac adaptation in hibernating, free-ranging Scandinavian Brown Bears (Ursus arctos)
Author
Jørgensen, Peter Godsk 1 ; Evans, Alina 2 ; Kindberg Jonas 3 ; Olsen, Lisbeth Høier 4 ; Galatius Søren 5 ; Fröbert Ole 6 

 University of Copenhagen, Department of Cardiology, Gentofte Hospital, Copenhagen, Denmark 
 Inland Norway University of Applied Sciences, Campus Evenstad, Department of Forestry and Wildlife Management, Elverum, Norway (GRID:grid.477237.2) 
 Swedish University of Agricultural Sciences, Umeå, Sweden and Norwegian Institute for Nature Research, Department of Wildlife, Fish and Environmental Studies, Faculty of Forest Sciences, Trondheim, Norway (GRID:grid.420127.2) (ISNI:0000 0001 2107 519X) 
 University of Copenhagen, Department of Veterinary and Animal Sciences, Frederiksberg, Denmark (GRID:grid.5254.6) (ISNI:0000 0001 0674 042X) 
 University of Copenhagen, Department of Cardiology, Bispebjerg Hospital, Copenhagen, Denmark (GRID:grid.5254.6) 
 Örebro University Hospital, Faculty of Health, Department of Cardiology, Örebro, Sweden (GRID:grid.412367.5) (ISNI:0000 0001 0123 6208) 
Publication year
2020
Publication date
2020
Publisher
Nature Publishing Group
e-ISSN
20452322
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2343198451
Copyright
This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.