An Amino Acid Mixture to Counteract Skeletal Muscle Atrophy: Impact on Mitochondrial Bioenergetics

Area of Science:

• Mitochondrial biology
• Skeletal muscle physiology
• Nutritional science

Background:

• Skeletal muscle atrophy (SMA) involves increased muscle breakdown and decreased protein synthesis, leading to mass and function loss.
• Mitochondrial dysfunction is implicated in the pathophysiology of SMA.
• Amino acids play a crucial role in muscle protein metabolism and mitochondrial function.

Purpose of the Study:

• To investigate the efficacy of an amino acid mixture (AA) in preventing skeletal muscle atrophy (SMA).
• To elucidate the role of mitochondria in AA's protective effects against SMA.
• To characterize the impact of AA on muscle mass, function, and mitochondrial bioenergetics in SMA models.

Main Methods:

• Induced skeletal muscle atrophy in C57/Bl6 mice via hindlimb immobilization (I) or cardiotoxin injection (C).
• Administered an amino acid mixture (AA) or placebo to mice for 10 days.
• Assessed muscle function (running time, distance, grip strength), muscle weight, myofiber size, and mitochondrial yield and bioenergetics in tibialis anterior (TA) muscles.

Main Results:

• Immobilization and cardiotoxin injury significantly reduced muscle function, mass, and myofiber size compared to controls.
• AA treatment prevented the loss of running time, distance, and grip strength.
• AA administration mitigated TA atrophy, preserved mitochondrial yield, and maintained mitochondrial bioenergetics in injured muscles.

Conclusions:

• An amino acid mixture (AA) effectively prevents skeletal muscle atrophy (SMA) in mouse models.
• AA protects against muscle mass and function loss by preserving mitochondrial integrity and bioenergetics.
• Targeting mitochondria with amino acids represents a promising therapeutic strategy for SMA.