Sarcopenia in Ageing: Why Muscle Loss Isn’t Just Senior Problem - Dr Brahmaraju T J

Sarcopenia, a term proposed by Rosenberg in 1989, is derived from the Greek words sarx (flesh) and penia (poverty), meaning the "poverty of flesh." It is a progressive syndrome characterized by the generalized loss of skeletal muscle mass and strength, leading to an increased risk of adverse outcomes such as physical disability, poor quality of life, and even death.

Causes of Sarcopenia

Sarcopenia is primarily associated with ageing, but several compounding factors accelerate its progression, including:

• Sedentary Lifestyle: Lack of physical activity contributes significantly to muscle atrophy.
• Poor Nutrition: Inadequate intake of proteins, vitamin D, and calcium negatively impacts muscle health.
• Underlying Diseases: Chronic conditions such as diabetes mellitus (DM) and chronic kidney disease (CKD) exacerbate muscle loss.
• Hormonal Changes: Reduced levels of anabolic hormones like testosterone, growth hormone, and insulin-like growth factor-1 (IGF-1) contribute to muscle deterioration.

Prevalence of Sarcopenia

Sarcopenia is a growing global health concern, affecting:

• 5–13% of individuals aged 60–70 years
• 11–50% of those over 80 years
• More than 50 million people worldwide today, with projections exceeding 200 million in the next 40 years

Effects of Sarcopenia

Sarcopenia becomes noticeable after the age of 40, leading to a progressive decline in skeletal muscle mass and function. This deterioration results in:

• Decreased Strength: Reduced muscle power impacts daily activities and independence.
• Increased Fat Deposition: Loss of muscle mass is often accompanied by fat infiltration, reducing overall metabolic efficiency.
• Decline in Muscle Function: Weakening muscles affect balance, mobility, and posture, increasing the risk of falls and injuries.

Consequences of Sarcopenia

The impact of sarcopenia extends beyond muscle loss, contributing to several critical health risks:

• Reduced Physical Activity: Weak muscles discourage movement, leading to a further decline in strength.
• Increased Fall Risk: Impaired balance and coordination raise the likelihood of falls.
• Higher Hospitalization Rates: Sarcopenia-related injuries often require prolonged medical care.
• Increased Morbidity and Mortality: Sarcopenia is associated with higher risks of fractures, prolonged immobilization, and reduced life expectancy.

Assessment of Sarcopenia

Sarcopenia is diagnosed through a multi-step evaluation process:

1. Identifying Cases: The SARC-F questionnaire is a simple screening tool assessing strength, assistance in walking, rise from a chair, climbing stairs, and falls.

2. Assessing Muscle Mass and Function:

• Imaging Techniques: MRI, DXA (Dual-energy X-ray absorptiometry), and CT scans measure muscle mass accurately.
• Muscle Strength Tests: Handgrip strength, knee extensor tests, and chair stand assessments evaluate functional capacity.
• Physical Performance Tests: Short Physical Performance Battery (SPPB), gait speed, and the Timed Up and Go (TUG) test assess mobility and balance.
• Biomarkers: Pro-inflammatory markers such as TNF-α, IL-6, and microRNAs indicate sarcopenic changes at the molecular level.

3. Confirming Diagnosis: A combination of low muscle mass, reduced strength, and impaired physical function confirms sarcopenia.

4. Grading Severity: Standard diagnostic criteria classify sarcopenia severity to guide treatment strategies.

Treatment and Advances in Managing Sarcopenia

1. Lifestyle Interventions

• Resistance Training: Strength exercises are the cornerstone of sarcopenia management, stimulating muscle hypertrophy and improving function.
• Nutritional Support: A diet rich in high-quality proteins, vitamin D, and essential amino acids supports muscle regeneration.
• Aerobic Exercise: Activities such as walking and cycling enhance overall endurance and cardiovascular health.

2. Emerging Therapeutic Strategies

• Muscle Regeneration Techniques: Research is focusing on stimulating myosatellite cell activation, which plays a vital role in muscle repair and growth.
• Targeted Molecular Pathways: Advances in modulating signalling pathways, such as IGF-1 and myostatin inhibition, aim to slow muscle degradation.
• Controlling Chronic Inflammation: Anti-inflammatory interventions targeting cytokines like TNF-α and IL-6 help reduce muscle wasting.

3. Advanced Medical Innovations

• Gene Editing and Stem Cell Therapy: Experimental approaches like CRISPR-based gene editing and stem cell transplantation show promise in enhancing muscle regeneration.
• MicroRNA Modulation: Targeting specific microRNAs involved in muscle degradation could revolutionize sarcopenia treatment.
• Pharmacological Interventions: Novel drugs are being developed to counter anabolic resistance and improve neuromuscular junction integrity.

Sarcopenia is a major challenge in ageing populations, significantly impacting mobility, independence, and overall health. Early identification and targeted interventions, including resistance training, proper nutrition, and emerging regenerative therapies, can help mitigate its effects.

Ongoing research in gene editing, stem cell therapy, and anti-inflammatory strategies holds immense potential in transforming sarcopenia management. A multidisciplinary approach involving orthopaedists, physiotherapists, nutritionists, and geriatric specialists is crucial to improving outcomes and enhancing the quality of life for ageing individuals.