Exercise and cytokines 3.0 Flashcards
Inflammation definition?
a defensive process that a living body initiates against local tissue damage
What can cause inflammation?
Physical agents, chemical agents, biological agents
What are the stages of inflammation?
Onset of inflammation, onset of resolution and resolution
What happens in the onset of inflammation?
Identification of damage, production of proinflammatory mediators, vasodilation and recruitment of white blood cells
Cytokines present in early inflammation?
TNF-alpa, IL1
Cytokines present in resolution of inflammation?
IL-10
What occurs during the onset of resolution of inflammation?
down regulation of pro-inflammatory signals, up regulation of anti-inflammatory signals, destruction of infecte tissue, clotting factors
Role of clotting factors?
stop clotting
What occurs during the resolution of inflammation?
production of anti-inflammatory mediators, apoptosis of immune cells, vascular repair
Five cardinal signs of inflammation?
Redness, heat, swelling, pain, loss of function
Outcome of increased blood flow?
Redness and heat
Outcome of accumulation of fluid?
swelling
Outcome of release of nerve stimulating chemicals?
pain
What are the 5 stages of inflammaiton resolution?
Removal of dead cells, restoration of vascular integrity, regeneration of tissue, remission of fever and relief of pain
Which biomarkers used to assess inflammation?
Acute phase proteins, cytokines
Which proteins increase or decrease in blood acutely in response to inflammation?
Acute phase proteins
What is an example of an acute phase protein?
CRP (C-reactive protein)
What is the role of CRP?
Helps clear dead cells
Where is CRP synthesised?
Liver
What are cytokines?
Small (hormone like) acute phase proteins released by a variety of different cells
What does IL6 do in regards to CRP?
induces its release from the liver
Meaning of pleiotropic?
Affects many different cell types in different ways
Autocrine hormone?
Acts on the cell it was released from
Paracrine action?
Acts on a nearby cell
Endocrine action?
Acts on a distant cell
IL8 role?
Chemokine–> a chemical that promotes chemotaxis
TNF-alpha role?
A pro-inflammatory cytokine that “ramps up” local inflammatory responses
IL1 role?
Affects nearly every cell type in the body, in synergy with TNF-alpha
Which cytokines are generally considered inflammatory?
IL8, TNF-alpha, IL1
Role of IL1RA?
Inhibition of IL1, so anti-inflammatory
Which cells produce IL-10?
macrophages, dendritic cells, t and b cells
Which cytokines are released near the beginning of infection?
TNF-alpha, IL1, IL8
Which cytokine is released in the middle of an infection?
IL6
Which cytokines are released at the end of an infection?
IL-1RA, IL-10
What is a bimodal response?
An acute spike followed by sustained elevation above baseline
What was observed in regard to IL6 levels and exercise?
A spike after exercise, followed by a maintained heightened level after the initial spike
What was initially thought to be the source of IL6? (THIS IS WRONG)
immune cells
What is eccentric exercise?
Uses target muscles to control a weight as it moves in a downward motion
Why is eccentric exercise used to assess the effect of muscle damage?
Eccentric exercise causes a lot of muscle damage in unaccustomed muscle compared to accustomed muscle, so they can be compared
What was observed in the 1999 study regarding IL6 and muscle damage?
There was no difference in IL6 released by muscles even when there were differences in the amount of muscle damage, thus muscle damage doesnt affect IL6
What was observed in the 2000 study regarding the absence of muscle damage on IL6?
IL6 release increased during exercise in the absence of muscle damage (as the exercise was only concentric)
How did the 2000 study show IL6 is produced as a result of exercise?
Did a bike test where one leg was exercising and one wasnt–> exercising leg produced most of the IL6
What was observed regarding the amount of increase in IL6 production over the duration of extended exercise in the 2000 study?
Initial increase was modest, later increase was dramatic
What was observed regarding muscle glycogen content and IL6 release at the start of exercise?
Lower muscle glycogen content caused a higher increase in IL6 during exercise
What was observed regarding muscle glycogen content and IL6 release at the end of exercise?
The muscle glycogen content did not massively affect the amount of IL6 released
What was confirmed regarding muscle glycogen content and IL6 secretion in the 2004 study?
Higher IL6 secretion is associated with depleted muscle glycogen content
Which processes does IL6 stimulate?
glycolysis and lipolysis
What cytokines does IL6 stimulate the release of?
IL-1RA and IL10
What is a myokine?
A signalling cell that is released in response to muscle contraction
What is inflammageing?
A gradual increase in basal inflammation as someone ages
What is inflammageing driven by?
Unresolved inflammation and immune dysregulation with ageing
What is an exokine?
A signalling moiety released in response to acute and/or chronic exercise
How do exokines exert their effects?
Endocrine, paracrine and/or autocrine mechanisms
What types of tissue can release exokines?
Skeletal muscle, heart, liver, WAT, BAT and neurons
What level of CRP is associated with inflammatory diseases?
> 3.0
Association between being physically active and CRP levels?
Being physically active is associated with lower CRP levels
