“Reduced ATP turnover during hibernation in relaxed skeletal muscle” is the title of the study published in the prestigious international journal Nature Communications by the research team led by Bert Blaauw, Full Professor at the Department of Biomedical Sciences, University of Padua, and Principal Investigator at VIMM.

The study uncovered a fascinating physiological adaptation in brown bears during hibernation: despite months of inactivity, they do not suffer from muscle wasting. The research identified a key mechanism behind this adaptation — a significant modulation of myosin ATPase activity in resting skeletal muscle. This enzymatic alteration plays a crucial role in energy conservation, allowing bears to preserve muscle mass throughout the long winter months of hibernation.

The analysis of single muscle fibers, collected from bears both during hibernation and in summer, revealed major changes occurring during overwintering. The fibers of hibernating bears showed a slight decrease in force production, accompanied by a marked reduction in myosin ATPase activity at rest. Myosin, the molecular motor of skeletal muscle, therefore exhibits a substantial decrease in enzymatic activity when the muscle is in a quiescent state during hibernation. These results highlight a physiological adaptation that contributes to energy saving during this period.

“Our findings demonstrate that skeletal muscle limits energy loss by reducing myosin ATPase activity, suggesting its potential role in multiple conditions of muscle atrophy,” explained Professor Blaauw. “This research opens up new therapeutic perspectives, suggesting potential strategies to counteract the loss of muscle mass and strength associated with prolonged inactivity or aging in humans. The insights gained from the adaptive mechanisms of hibernating bears could provide valuable guidance for developing targeted interventions to preserve muscle function in conditions of disuse or senescence.”