Metabolic response to injury and infection Flashcards
Explain what happens to energy metabolism in burns (being burnt):
- EE is raised quite dramatically
- increased utilisation and oxidation of fatty acids
- increase in REE/oxygen usage
What drives hypermetabolism and hypercatabolism?
hormonal activation (heightened catabolic hormones and cytokines) - catecholamines
What happens as a result of hypermetabolism and hypercatabolism?
- lypolysis
- glycogenolysis
- cortisol and inflammatory - - cytokines cause muscle protein breakdown
- raised gluconeogenesis
What happens as a consequence of anabolic resistance?
- during stress response, androgens and other anabolic mediators are suppressed (reduction in LH production)
- insulin resistance (a major anabolic hormone)
- GH raised, but IGF-1 from liver is reduced
- binding proteins are altered
What is the purpose of a stress response?
Reprioritisation of activities towards immune activity/function and hepatic synthesis of acute phase proteins, APPs (and gluconeogenesis)
What is the inflammatory cytokines role in the stress response?
orchestrates the response
What happens as a result of inflammatory cytokines orchestrating stress response?
- Reduced muscle protein synthesis
- increased breakdown
- net release of amino acids
What are one of the side effects of illness/injury?
muscle wasting
What are the effects of protein metabolism in combination with bed rest/reduced physical activity/anorexia?
- loss of lean tissue from muscles (depends on severity/duration)
- increases morbidity and mortality
What is common in sepsis?
mitochondrial dysfunction
What happens as a result of mitochondrial dysfunction in sepsis?
- lead to organ failure
- associated with risk of death
What are the effects of systemic inflammation in sepsis?
- heightened inflammatory cytokine release
- ROS production
- Catabolic hormone mediators
- impaired perfusion early in shock, reduced O2
- ROS effects on complex activity in mitochondria
- Effects on gene transcription of mito. biogenesis markers
- Low T3
- Damaged mito. undergo mitophagy
What are some examples of ROS?
- Nitric oxide
- Hydrogen sulphide
- carbon monoxide
What are some examples of mitochondria biogenesis markers?
- PGC-1a
- NRFs
What is T3’s role on mitochondria?
Has potent effect on mito. function and biogenesis
