Sarcopenia--The search for emerging biomarkers

Area of Science:

• Gerontology and Muscle Physiology
• Molecular Mechanisms of Aging

Background:

• Sarcopenia, an age-related decline in skeletal muscle mass and function, significantly impacts the quality of life for the elderly and poses a substantial burden on healthcare systems.
• Despite consensus on its multifactorial nature, the precise etiology, mechanisms, and definition of sarcopenia remain unclear, hindering effective treatment development.

Purpose of the Study:

• To critically analyze potential sarcopenia biomarkers by examining their molecular mechanisms in sarcopenia pathogenesis.
• To propose emerging biomarkers based on the proposed shift in molecular balance underlying sarcopenia.

Main Methods:

• Review of literature on molecular regulators of muscle mass and function.
• Analysis of the proposed shift in the balance between positive and negative regulators of muscle growth.
• Investigation of the role of C-terminal agrin fragment (CAF) and skeletal muscle-specific troponin T (sTnT) in sarcopenia.

Main Results:

• Normal muscle maintenance depends on a balance between muscle growth promoters (e.g., BMPs, BDNF, FST, irisin) and inhibitors (e.g., TGFβ, myostatin, activins, GDF-15).
• A shift towards muscle growth inhibitors, coupled with increased CAF and sTnT expression, is hypothesized as a primary mechanism in sarcopenia.
• CAF is linked to age-dependent neuromuscular junction (NMJ) dysfunction, and sTnT is a key contractile machinery component.

Conclusions:

• The identified molecules, including growth inhibitors, CAF, and sTnT, represent emerging biomarkers for sarcopenia.
• Understanding these molecular players and their imbalance is critical for developing targeted sarcopenia treatments.
• Further research into these biomarkers could elucidate sarcopenia pathogenesis and inform therapeutic strategies.