Swiss Army knife bears reveal anti-blood-clotting secret

If you've ever taken a long airplane ride, you've no doubt heard that you should get up and move periodically to avoid developing blood clots. That's because when our bodies are stationary for long periods of time, the odds of our blood pooling, coagulating, and clotting go up.

Yet bears can spend months in the same position in their caves while hibernating without this concern. New research has uncovered why that is, and the findings could have implications to create better anti-clotting treatments for people.

In a study that was over a decade long, a team led by researchers from German and Swedish institutions took blood samples from brown bears in Sweden during the depths of their hibernation phase in winter, as well as during their active periods in the summer months.

They found that when the bears were hibernating, a protein known as HSP47 was nearly absent in the blood samples. This protein covers the surface of blood platelets, and helps attract and bind to white blood cells to create the net-like structures involved in clot formation. When the bears returned to their active periods, levels of HSP47 increased.

Building on this knowledge, the researchers genetically engineered mice to not produce HSP47. The result was that the mice's ability to form blood clots greatly diminished.

Image source: Frobert & Tobias Petzold.