Sarcopenia: etiology, clinical consequences, intervention, and assessment

Area of Science:

• Gerontology
• Skeletal Muscle Physiology
• Cellular Biology

Background:

• Aging is characterized by progressive loss of muscle mass and strength, termed sarcopenia.
• Sarcopenia encompasses cellular mechanisms driving skeletal muscle loss and clinical outcomes.
• Age-related cellular changes include reduced anabolic factors and increased inflammatory and catabolic factors.

Purpose of the Study:

• To review the mechanisms underlying sarcopenia and age-related muscle changes.
• To discuss the impact of these changes on muscle morphology and function.
• To examine the long-term consequences of sarcopenia, including frailty and loss of independence.

Main Methods:

• Literature review of current understanding of sarcopenia mechanisms.
• Analysis of cellular and molecular processes contributing to muscle loss.
• Synthesis of research on the functional and clinical manifestations of sarcopenia.

Main Results:

• Cellular changes involve impaired muscle anabolism and enhanced catabolism.
• Muscle fiber cross-sectional area decreases, innervation is lost, and motor unit composition shifts.
• These changes result in reduced muscle mass, strength, and physical performance.

Conclusions:

• Sarcopenia is a multifactorial condition driven by complex cellular and molecular alterations.
• The functional decline associated with sarcopenia increases the risk of falls, injuries, and frailty.
• Understanding these mechanisms is crucial for addressing age-related functional decline and maintaining independence.