Researchers suggest that a protein, observed in hibernating bears, could be the key to a new treatment for blood clots and venous thrombosis.
- Despite weeks of immobilization, brown bears do not develop thrombosis during hibernation. Faced with this observation, German researchers decided to study the animal.
- They found that brown bears had low levels of a protein called HSP47 during hibernation. He believes that this element can help prevent the formation of blood clots and venous thrombosis.
- However, more research is needed to come up with a new treatment for the disease.
Whether for a hospitalization of several weeks or even for a flight of more than 8 hours, being immobilized for a long period increases the risk of developing blood clots or venous thrombosis in humans. On the other hand, the brown bear can spend the whole cold season sleeping in its den without any worries. Faced with this observation, researchers at the Ludwig-Maximilians University Hospital in Munich (LMU Klinikum) decided to study the blood platelets of hibernating bears more closely. They discovered that these animals had low levels of a protein called HSP47.
Hibernation and blood clot: 55 times lower heat shock protein levels
For this study published in the journal Science on April 13, 2023, scientists traveled to Sweden to take blood samples from 13 brown bears: the first time in the middle of winter while they were hibernating and the second time in the summer during their active period.
They noticed that during hibernation, “the interaction between blood platelets and inflammatory cells of the immune system is slowed down”. For Dr. Tobias Petzold who worked on this experiment, this phenomenon “explains the absence of venous thrombosis”. His team has also noticed similar processes in paraplegic patients as well as in healthy volunteers who have been bedridden for three weeks as part of an experiment conducted by the European and American space agencies.
To better understand this mechanism, they observed the proteins present in the bears’ blood samples. In detail, the rate of 71 proteins was up and down for 80 others. Dr. Johannes Müller-Reif, first author of the study, specifies in a press release from his university : “The platelet protein showing the greatest difference between hibernating and active bears was heat shock protein 47 (HSP47), levels of which were 55 times lower in hibernating bears”.
This protein is known to be present in cells that form connective tissues like bone and cartilage as well as platelets. It binds to collagen, among other things. This can cause the platelets to stick together and form a clot.
Venous thrombosis: protein may lead to new treatment
During their experiments, the researchers were able to show that the negative regulation of HSP47 occurs during long immobilization in different species of mammals: brown bears, pigs, but also humans. Low levels of the protein reduce the interaction of platelets and inflammatory cells. This mechanism would help prevent thrombosis.
“In biomedical terms, this means that if the HSP47 protein could be blocked with an appropriate molecule in immobilized patients, the risk of venous thrombosis could possibly be avoided. Molecules that deactivate HSP47 already exist in the laboratory”, explain the scientists. However, these are not suitable for possible use in humans. The researchers hope to be able to continue their work and come up with new treatments for thrombosis and blood clots.