Cardiophysiology: Pathogenesis of Obesity Flashcards
(38 cards)
What happens to adipocytes when they experience excessive growth?
Apoptosis and necrosis which leads to inflammation.
What are leptin’s functions?
Reduces appetite (binds to neurons in the brain)
Affects milk production
Affects fetal growth
Why do fat cunts still eat so much with so much fat?
Obese people develop leptin resistance.
What happens to leptin levels during cardiac failure and ischaemia?
they rise independently of obesity
What is the other effect that leptin has on the brain?
Acts on the ventromedium hypothalamus which acts on the sympathetic nervous system.
What effect does increased leptin have on sympathetic activity and how does it do this?
The ventromedium hypothalamus does not lose sensitivity as quickly as the neurons in the brain responsible for appetite do.. As a result sympathetic activity increases
What happens to lean animals when acutely given leptin?
Increased natriuresis
Increased NO production
Decrease in Na+ transporter expression and as a result less Na+ retention
What happens in animals with chronic hyperleptinaemia?
Increase in sodium retention.
NO deficiency
Increase in renal oxidative stress
What is TNF-alpha?
Pro inflammatory cytokine produced by immunocytes
What is TNF-alpha produced in response to?
Leptin
What cells produce TNF-alpha?
monocytes and macrophages
What does weight loss do to TNF-alpha levels?
It drops TNF-alpha levels which decreases insulin resistance.
What is the function of TNF-alpha?
Pro inflammatory
Correlated with insulin resistance
What effect does increased TNF-alpha have in obese people?
An increase in TNF-alpha causes people to develop metabolic conditions more often
What conditions result from too much TNF-alpha?
TNF-alpha is associated with increase in acute and chronic ischaemia and heart failure.
TNF-alpha induces migration, inflammation, and apoptosis of smooth muscle and this is associated with vascular degeneration.
Adhesion molecule formation
How does TNF-alpha cause vascular degeneration?
TNF-alpha induces migration, inflammation, and apoptosis of smooth muscle
What is adiponectin?
Anti-inflammatory adipokine that is reduced in obese individuals and higher in lean individuals.
What is low adiponectin a marker of?
Type 2 diabeetus
Left ventricular hypertrophy
myocardial infarction
coronary artery disease
How is adiponectin reduced?
It is reduced in obese individuals by leptin and tnf-alpha expression
What does adiponectin do?
Reduces inflammation
exerts protective effects on endothelial cells and cardiomyocytes
What happened to knock out mice after they were given adiponectin?
Revascularization of ischaemic limbs
Reduced cerebral reperfusion injuries
What happens to blood pressure in adiponectin deficient mice?
Salt-sensitive hypertension develops.
Nitric Oxide production is reduced resulting in less vasodilation and in turn higher blood pressure
What effect does adiponectin have on atherosclerosis?
overexpression inhibits in lesion formation
Deficiency augments atherosclerosis
What happens to insulin resistance with high adiponectin levels?
it is reduced
