Lecture 23 Flashcards
What is the inflammation required for muscle hypertrophy?
acute inflammation
What are the inflammatory response mediators?
Inflammatory response is mediated by macrophages neutrophils and monocytes or by cytokines/chemokines.
What are some potential causes of the inflammatory response?
saturated fatty acids, bacterial products, and mechanical stress can cause inflammatory response.
What is the function of immune cells in the inflammatory response?
macrophages monocytes and neutrophils mediate pathogen clearance followed by satellite cell repair.
What are the steps of responding to muscle injury?
Destruction ->repair->remodelling
How long are immune cells typically involved in inflammation for?
immune cell involvement occurs for 14 days
What happens to inflamed muscles if macrophages are not present?
When macrophages are knocked out response of mice to muscle damage is slowed down until macrophages were reintroduced.
Macrophages are necessary for skeletal muscle repair.
What cytokines are expected to be found during sepsis?
TNF, IL-6, IL-10 and other cytokines.
What cytokine is not found in the exercise response but is found during sepsis?
TNF is not activated by exercise. IL-6 is the main cytokine to respond to exercise.
What regulates the amount of IL-6 produced?
IL-6 gets upregulated depending on muscles recruited, exercise intensity, and duration.
What is the function of myokines?
myokines ‘talk’ to other tissue as well as the muscles themselves. these myokines effect muscle hypertrophy, angiogenesis, and fat oxidation, and lipolysis in other tissue.
What is the function of IL-6 in hypertrophy?
IL-6 promotes satellite cell activation and hypertrophy. It activates a receptor called GP130 and this activates the JAK/STAT pathway.
JAK/STAT pathway is linked to the Akt pathway which is involved in inhibiting protein degradation and stimulating protein synthesis.
How does IL-6 binding to GP130 affect JAK and STAT3?
Phosphorylation
Which STAT does IL-6 signal through?
IL-6 generally signals through STAT3.
What happens to LIF during and after exercise?
LIF is significantly upregulated during and after exercise.
What does STAT3 do in the cell?
STAT3 colocalizes to nuclei and acts directly on transcription.
Which exercise does STAT5 respond to?
STAT5 is phosphorylated after aerobic exercise and not resistance exercise.
What is the hypothesized activator of STAT5?
STAT5 activation is thought to be caused by exercise induced growth hormone.
What are some factors that influence the inflammatory response?
Training status
Aging
Gender
Medications
How does IL-6 release respond to training? (trained vs untrained)
How are STAT3 and SOC6 affected?
single boat of HIIT upregulates IL-6. But this does not change with more training.
STAT3 and SOC6 are not decreased with training.
Why doesn’t IL-6 change in response to becoming trained?
Despite conditioning of the muscle there is still a need for the inflammatory response to occur.
How does aging affect inflammation?
With aging there is a chronic basal level of inflammation that is present.
Aging is associated with increase in free radical generation? These free radicals can cause modification of protein, lipids, and DNA.
Inflammatory response to mechanical stress may be altered with age.
How does white blood cell release response to exercise change in elderly and young people?
White blood cell release does not change in response to exercise between young and elderly.
How does macrophage response to exercise change in young people compared to old? (answer is weird needs more research)
Greater macrophage response in young people in response to exercise compared to older people.
What is the difference between PLASMA IL-6 levels between young and elderly before and after exercise?
PLasma IL-6 levels at rest are greater in elderly compared to young.
Plasma IL-6 response to exercise is higher in young people compared to elderly.
What is the difference between MUSCULAR IL-6 levels between young and elderly before and after exercise?
Upregulation of IL-6/STAT3 following exercise
During exercise it’s greater in elderly compared to young people.
How are SOCS3 levels different in elderly compared to young people?
SOCS3 is higher in elderly following exercise compared to young person.
What is the higher levels of SOCS3 in elderly evidence of?
Exercise induced translation of SOCS3 the negative regulator of STAT3 is dysregulated with age.
How does neutrophil production differ between genders?
2 hours after exercise women express different amounts of neutrophils to men and this effect diminishes after 4 hours.
What happens to the immune response difference between genders over an extended period of time?
females have an elevated initial immune response this is not reflected by the infiltration of macrophages 24 hours post exercise
How are IL-6/STAT3 levels different in males and females?
No difference in IL-6/STAT3 between young (and old) males and females following exercise.
What is the effect of anti inflammatory drugs on hypertrophy?
anti inflammatory drugs decrease the effect of inflammation which is essential for hypertrophy. These drugs decrease inflammation.
satellite cells in muscle repair are inhibited by anti inflammatory drugs.
