Preventing muscle wasting with serum from hibernating black bears
Human skeletal muscle cells infused with serum from the blood of hibernating black bears exhibited significant protein growth leading to an increase in muscle mass. The fascinating discovery was made by scientists at Hiroshima University and Hokkaido University in Japan, and highlighted how “hibernating bear serum” could be used to prevent muscle atrophy, or muscle wastage, caused by immobility.
Hibernating bears have been known to stay still for up to seven months without eating or drinking, without severe impacts to their health and physical being, whereas humans are prone to losing muscle mass within just three weeks of inactivity.
The scientists chose to study hibernating bears in the hopes of preventing sedentary lifestyle diseases in humans, including obesity, diabetes, and cardiovascular disease. Unlike serum drawn from hibernating black bears, serum collected during the bears’ active summer season did not induce protein or muscle growth.
The scientists believe this is due to a factor in the hibernating bear serum that suppresses a “destruction mechanism” unique to muscle degradation, which normally kicks into action when we don’t use them. They also attribute bears’ resistance to muscle atrophy to the suppression of a protein called MuRF1 that activates the shredding of unused muscles.
“We have indicated that ‘some factor’ present in hibernating bear serum may regulate protein metabolism in cultured human skeletal muscle cells and contribute to the maintenance of muscle mass. However, the identification of this ‘factor’ has not yet been achieved,” said Mitsunori Miyazaki, Associate professor at Hiroshima University’s Graduate School of Biomedical and Health Sciences.
“By identifying this ‘factor’ in hibernating bear serum and clarifying the unexplored mechanism behind ‘muscles that do not weaken even without use’ in hibernating animals, it is possible to develop effective rehabilitation strategies in humans and prevent [humans] becoming bedridden in the future.”
Further research could inform strategies focused on preventing muscle wastage in people who are immobile due to aging or disease, and additionally open up some exciting possibilities around protecting humans during deep space travel, which poses health risks due to high levels of radiation.
