Sleep like a bear

Abstract

Deep vein thrombosis (DVT) is a common feature of short-term immobilization, which occurs, for example, for patients with acute paralysis. However, in chronic immobilization—e.g., owing to spinal cord injury (SCI)—the incidence of DVT equals that in the general population (1). The mechanisms that protect against DVT during chronic immobilization in SCI patients are unknown. On page 178 of this issue, Thienel et al. (2) report an analysis of the thromboinflammatory machinery in hibernating brown bears (Ursus arctos), which rarely suffer from DVT despite 6 months of immobilization during hibernation (3). They found that platelets from hibernating bears exhibit an antithrombotic signature characterized by decreased expression of heat shock protein 47 (HSP47) and overall reduced biomarkers of thromboinflammation compared with those of active brown bears. Further, this signature is conserved across different animal species, including mice, pigs, and humans, suggesting that this could be a therapeutic target to reduce DVT in immobilized patients.