Ageing Muscles May Sacrifice Strength To Prevent Cell Damage, Study Reveals

Scientists have reported that the natural decline in muscle strength during ageing may involve an unexpected protective response rather than simple failure. A recent study conducted by researchers at the University of Copenhagen suggests that ageing muscles might trade strength to protect cells from damage.

Key Findings From The Study

• Cardiolipin Molecule: Researchers identified that cardiolipin, a specialised fat molecule found in mitochondrial membranes, declines in ageing or diseased muscles in both mice and humans.
• Fibre Type Shift: Lower cardiolipin levels prompt a shift from fast-twitch fibres, which generate rapid movements, to slow-twitch fibres, which support sustained activity.
• Protective Signalling: The reduction in cardiolipin causes damaged mitochondria to produce reactive oxygen species (ROS), which act as stress signals triggering the muscle fibre adaptation.
• Metabolic Adaptation: Experiments indicated that muscle cells redirect glucose to produce internal antioxidants rather than energy, helping defend against oxidative stress.

Experimental Results In Mice

When researchers reduced cardiolipin levels in young mice, their muscles showed a similar transition to slow-twitch fibres. Furthermore, restoring cardiolipin to roughly two-thirds of normal levels reversed signs of muscle wasting and prevented premature deaths in the studied mice. Assistant Professor Fabian Finger noted that interfering with this protective response using antioxidants made the muscles fare worse, indicating a trade-off between power and cellular protection.

Future Implications And Limitations

While the findings offer a new perspective on muscle ageing, the therapeutic potential for humans remains unconfirmed. The experiments involving restoration and protective mechanisms were performed on mice, while human samples were only used to confirm declining cardiolipin levels with age.

Researchers noted that existing pathways could eventually be explored. For instance, the US Food and Drug Administration recently granted accelerated approval to elamipretide for Barth syndrome, a rare inherited disorder, as it helps stabilise cardiolipin. However, its efficacy against age-related muscle loss is currently unknown. Associate Professor Zachary Gerhart-Hines highlighted that future research must determine whether similar interventions can safely promote healthy adaptations in humans.

*Readers should consult a qualified healthcare provider for any medical advice or questions regarding health conditions.*