Trigger 1: Sarcopenia Flashcards
What is the primary role of leucine in muscle protein synthesis?
A. Breakdown of autophagy
B. Inhibition of mTOR pathway
C. Direct initiation of mRNA translation
D. Reduction of inflammatory markers
C. Direct initiation of mRNA translation
Skeletal muscle hypertrophy is a ______ process.
Local
Chronic low-grade inflammation is positively correlated with muscle strength and mass. True or False.
False
Name one factor associated with anabolic resistance in older adults.
Hormonal changes
Match the following pathway with its role: PI3K-Akt-mTOR.
A. Autophagy initiation
B. Protein synthesis activation
PI3K-Akt-mTOR: B. Protein synthesis activation
Describe the mechanism by which leucine modulates the mTOR pathway.
Leucine modulates mTOR via the RAG GTPase pathway, forming an active Rag complex that recruits and activates mTORC1. This activation leads to phosphorylation of downstream targets, including p70S6K and 4E-BP1, promoting protein synthesis and inhibiting autophagy.
Explain how chronic inflammation in aging individuals contributes to muscle loss.
Chronic inflammation, combined with aging, increases fat content, leading to fat infiltration in myocytes. This induces mitochondrial dysfunction, elevating ROS through lipid oxidation. The enhanced IGF-1-PI3K-mTOR pathway is then activated, resulting in reduced protein synthesis and contributing to muscle atrophy.
What is the primary storage site for amino acids in the body?
Skeletal muscle
The breakdown of autophagy balance can impair muscle function due to the dysfunction of autophagy in the process of mitochondrial clearance. Which of the following is responsible for initiating autophagy?
A. Leucine
B. mTOR
C. IGF-1
D. AMPK
D. AMPK
Anabolic resistance in older adults is closely associated with the loss of muscle mass, strength, and function, and may be related to the non-response of ERK1/2 signal and ______ activation in aging muscles.
AMPK
Omega-3 fatty acids, particularly EPA and DHA, have been shown to have pro-inflammatory effects. True or false.
False
Match the muscle-related factor with its characteristic.
A. Sarcopenia
B. Hypertrophy
C. Anabolic resistance
A. Loss of muscle mass with aging
B. Increase in muscle fiber size
C. Reduced response to anabolic signals
Sarcopenia: A. Loss of muscle mass with aging
Hypertrophy: B. Increase in muscle fiber size
Anabolic resistance: C. Reduced response to anabolic signals
Describe the mechanism by which IGF-1 activates the PI3K-Akt-mTOR pathway.
IGF-1 binds to the IGF-1 receptor on the surface of muscle cells which activated the intracellular adaptor protein IRS-1, initiating a cascade of events that involve activation of PI3K is thus phosphorylated and Akt, subsequently activating Akt.Pi3K converts PIP2-PIP3 which binds to PKB/Akt activating it. PKB/Akt then activated mTOR. This pathway leads to increased protein synthesis and muscle growth.
How does leucine modulate the mTOR pathway, and what role does it play in the aging muscle response to amino acid intake?
Leucine modulates mTOR via the RAG GTPase pathway, forming an active Rag complex that activates mTORC1. This activation promotes protein synthesis and inhibits autophagy. In aging muscles, leucine supplementation improves the slow response to amino acid intake, contributing to increased protein synthesis.
What is the primary function of satellite cells in muscle tissue?
Satellite cells are muscle-resident stem cells essential for muscle tissue repair and regeneration.
Omega-3 fatty acids, particularly EPA and DHA, have been shown to stimulate muscle protein synthesis, especially in _______ adults.
Older
Which of the following is a potential role of myostatin inhibitors in addressing muscle atrophy?
- A. Increase in muscle protein breakdown
- B. Inhibition of muscle growth
- C. Stimulation of satellite cell activity
- D. Reduction in protein synthesis
C. Stimulation of satellite cell activity
Myostatin, also known as GDF-8, promotes skeletal muscle growth. True or False.
False
Explain the term “anabolic resistance” in the context of aging muscles.
Anabolic resistance refers to the reduced ability of aging muscles to respond to anabolic signals, leading to decreased protein synthesis and muscle growth.
Compare and contrast the mechanisms of action between selective androgen receptor modulators (SARMs) and anabolic steroids.
SARMs selectively bind to androgen receptors, promoting protein synthesis in muscle tissue with fewer side effects. Anabolic steroids, on the other hand, replicate the effects of testosterone, affecting various tissues and organs.
What are some health considerations associated with the use of NSAIDs in older individuals?
NSAIDs elevate the risk of myocardial infarction, stroke, gastrointestinal bleeding, and acute renal failure in older patients.
Propose a non-pharmaceutical intervention to reduce age-related muscle atrophy for an elderly individual with limited mobility.
Implement resistance training tailored to the individual’s abilities, focusing on exercises that target major muscle groups and stimulate protein synthesis.
What is the primary role of leucine in regulating muscle protein synthesis?
A. Inhibition of mTOR pathway
B. Activation of autophagy
C. Stimulation of mRNA translation
D. Reduction of amino acid storage
C. Stimulation of mRNA translation
Autophagy is a cellular process that promotes muscle protein synthesis. True or False
False