Muscle loss

Extracted Attributes

• Mechanism

  Imbalance between protein synthesis and protein degradation

• Definition

  Loss of skeletal muscle mass

• Alternative Names

  Muscle atrophy, Sarcopenia (age-related muscle atrophy), Cachexia (wasting syndrome due to underlying disease), Volumetric muscle loss (VML)

• Primary Consequence

  Muscle weakness and disability

• Treatment Approaches

  Addressing underlying cause, exercise, adequate nutrition, minimizing immobility

• Reversibility - Cachexia

  Not completely reversible with nutritional therapy

• Reversibility - Sarcopenia

  Can be slowed or mitigated by exercise

• Reversibility - Disuse Atrophy

  Often fully reversible with activity

• Skeletal Muscle Body Mass Contribution

  40%-45% of total body mass

• Skeletal Muscle Regenerative Potential

  High adaptability; can compensate up to 20% loss, but beyond that, full regeneration is impaired

• Reversibility - Malnutrition-induced Atrophy

  Reversible with nutritional therapy

Timeline

• Most adult humans achieve peak muscle mass sometime during their early 40s. (Source: web_search_results)

  Unknown

• After peak muscle mass (early 40s), a gradual deterioration/loss of muscle mass begins. (Source: web_search_results)

  Unknown

• Sarcopenia was recently recognized as a disease with an International Classification of Disease (ICD) code. (Source: web_search_results)

  Unknown

Muscle atrophy

Muscle atrophy is the loss of skeletal muscle mass. It can be caused by immobility, aging, malnutrition, medications, or a wide range of injuries or diseases that impact the musculoskeletal or nervous system. Muscle atrophy leads to muscle weakness and causes disability. Disuse causes rapid muscle atrophy and often occurs during injury or illness that requires immobilization of a limb or bed rest. Depending on the duration of disuse and the health of the individual, this may be fully reversed with activity. Malnutrition first causes fat loss but may progress to muscle atrophy in prolonged starvation and can be reversed with nutritional therapy. In contrast, cachexia is a wasting syndrome caused by an underlying disease such as cancer that causes dramatic muscle atrophy and cannot be completely reversed with nutritional therapy. Sarcopenia is age-related muscle atrophy and can be slowed by exercise. Finally, diseases of the muscles such as muscular dystrophy or myopathies can cause atrophy, as well as damage to the nervous system such as in spinal cord injury or stroke. Thus, muscle atrophy is usually a finding (sign or symptom) in a disease rather than being a disease by itself. However, some syndromes of muscular atrophy are classified as disease spectrums or disease entities rather than as clinical syndromes alone, such as the various spinal muscular atrophies. Muscle atrophy results from an imbalance between protein synthesis and protein degradation, although the mechanisms are incompletely understood and are variable depending on the cause. Muscle loss can be quantified with advanced imaging studies but this is not frequently pursued. Treatment depends on the underlying cause but will often include exercise and adequate nutrition. Anabolic agents may have some efficacy but are not often used due to side effects. There are multiple treatments and supplements under investigation but there are currently limited treatment options in clinical practice. Given the implications of muscle atrophy and limited treatment options, minimizing immobility is critical in injury or illness.

Web Search Results

• Slowing or reversing muscle loss - Mayo Clinic

  "Without question, exercise is the most powerful intervention to address muscle loss, whether it occurs in the context of advancing age or debilitating chronic or acute diseases," explains Nathan K. LeBrasseur, Ph.D., of the Department of Physical Medicine and Rehabilitation at Mayo Clinic in Rochester, Minn. "However, researchers are also searching for pharmacological therapies to help improve skeletal muscle mass among people who are bedbound or unable to exercise for other reasons." [...] Most adult humans achieve peak muscle mass sometime during their early 40s. After that point, a gradual deterioration begins. The progressive loss of skeletal muscle mass that accompanies aging (sarcopenia) and disease (cachexia) can impair muscle performance, physical function and whole-body metabolism. The declines in physical function and mobility associated with sarcopenia and cachexia can lead to falls, loss of independence, institutionalization and even death. Given the severity of these [...] (hypertrophy). These observations have led to the hypothesis that myostatin inhibition could serve as a means to attenuate or reverse skeletal muscle mass loss in patients affected by sarcopenia, cachexia and genetic disorders such as muscular dystrophy.

• Current Methods for Skeletal Muscle Tissue Repair and Regeneration

  Progressive muscle loss can result from metabolic disorders or inherited genetic diseases such as Duchenne muscular dystrophy, Amyotrophic Lateral Sclerosis, and pediatric Charcot-Marie-Tooth disease [10–13]. Muscle atrophy can also be a consequence of peripheral nerve injuries, chronic kidney disease, diabetes, and heart failure [14, 15]. Up to 20% loss of muscle mass can be compensated by the high adaptability and regenerative potential of skeletal muscle. Beyond this threshold functional [...] Skeletal muscle injury or loss occurs in many clinical situations. Surgical techniques are highly developed and can provide good results for reconstructing muscle function, if all goes well. Surgery is always associated with considerable risks and high costs and even if successful, usually better function at one location is traded for impaired function at another location that is less important for the patient. Research into tissue engineering and regenerative cell therapy may overcome these [...] Skeletal muscle is one of the most abundant tissues in the human body. It accounts for 40%–45% of the total body mass and is necessary for generating forces for movement . Up to a certain threshold, skeletal muscle has the capability of regenerating lost tissue upon injury . Beyond this threshold, the remaining muscle tissue is unable to fully regenerate its function. This loss of skeletal muscle with lasting functional impairment is defined as “volumetric muscle loss” (VML) [3–5]. It can

• Muscle Atrophy: Causes, Symptoms & Treatment - Cleveland Clinic

  Muscle atrophy is the loss or thinning of your muscle tissue. If you have atrophied muscles, you’ll see a decrease in your muscle mass and strength. With muscle atrophy, your muscles look smaller than normal. Muscle atrophy can occur due to malnutrition, age, genetics, a lack of physical activity or certain medical conditions. Disuse (physiologic) atrophy occurs when you don’t use your muscles enough. Neurogenic atrophy occurs due to nerve problems or diseases. Advertisement [...] ### What is the difference between muscle atrophy and muscle hypertrophy? Muscle atrophy is a loss of muscle mass. Muscle hypertrophy is an increase of your muscle mass. Your muscle fibers get bigger or thicken. Muscle hypertrophy occurs due to an increase in the volume of your muscle cells. You may experience muscle hypertrophy through workout routines such as strength training or high-intensity interval training (HIIT). ### A note from Cleveland Clinic [...] Gray gradient Gray gradient Search Icon Blue Cleveland Clinic logo # Muscle Atrophy Muscle atrophy is the wasting or thinning of muscle mass. It can be caused by disuse of your muscles or neurogenic conditions. Symptoms include a decrease in muscle mass, one limb being smaller than the other, and numbness, weakness and tingling in your limbs. Disuse atrophy can be reversed with exercise and a healthy diet. Advertisement

• Sarcopenia (Muscle Loss): Symptoms & Causes - Cleveland Clinic

  ### A note from Cleveland Clinic Everyone experiences some amount of muscle loss as they age. But with sarcopenia, this muscle loss happens faster. The good news is, there are ways to treat and even reverse the effects of the condition. If you’ve experienced muscle weakness, loss of endurance or any other symptoms of sarcopenia, call your healthcare provider. They can diagnose the condition and develop a treatment plan for you to revert the muscle loss and improve your condition. [...] The medical definition of sarcopenia is the gradual loss of muscle mass, strength and function. The condition commonly affects the elderly population and is thought to occur due to aging. Sarcopenia can greatly impact your quality of life by reducing your ability to perform daily tasks. It can lead to the loss of your independence and the need for long-term care. Advertisement [...] ### What’s the difference between sarcopenia and muscle atrophy? Sarcopenia is a type of muscle atrophy that specifically affects people as they grow older. Muscle atrophy is the loss of muscle tissue. The two conditions share common features of muscle loss, but the processes behind them are different. A decrease in the size and number of your muscle fibers causes sarcopenia. With muscle atrophy, there’s a reduction in the size of the fibers, but the amount of fibers stays the same.

• Nutritional strategies for maintaining muscle mass and strength from ...

  2022, Ageing Research Reviews Show abstract The loss of muscle mass, strength and function, known as sarcopenia, is common in older adults, and is associated with falls, fractures, cardiometabolic diseases, and lower quality of life. Sarcopenia can also occur secondarily to chronic diseases. Recently, sarcopenia was recognized as a disease with an International Classification of Disease (ICD) code, yet, at least five definitions for its clinical identification exist. Most definitions include [...] independent of muscle mass loss . Lower body strength declines by 3 %–4 % annually, even though only approximately 1 % of leg lean mass is lost annually . In healthy older adults, muscle power declines more quickly than muscle strength . [...] Inadequate fruit and vegetable intake increases the diet’s net acid load, which is associated with loss of muscle mass. In addition, acidogenic diets may stimulate proteolysis and amino acid catabolism, increasing muscle-protein breakdown . With aging, the ability to excrete hydrogen ions declines, and other means are employed to preserve a neutral pH. These include bone resorption, a process that releases alkali into the circulation, and also muscle degradation, which facilitates the renal