L11 - atherosclerosis Flashcards
Define ‘atherosclerosis’
The accumulation of lipid in the intima and media of medium and larger arteries
Define ‘arteriosclerosis’
The hardening of artery walls as a consequence of atherosclerosis’
What are the macroscopic features of atherosclerosis?
Presence of fatty streaks and plaques
What are ‘fatty streaks’?
Accumulation of foam cells in the artery walls
What are the three major components of an atherosclerotic plaque?
Cells (macrophages, SMC’s, leukocytes)/lipid/ECM
Give two common sites where atherosclerosis takes place
Aorta/coronary arteries/carotid arteries/cerebral arteries/leg arteries
Give the early microscopic features of atherosclerosis
Proliferation of SMC’s/accumulation of foam cells/ EC lipid deposition
Give some late microscopic features of atherosclerosis
Fibrosis/plaque necrosis/cholesterol clefts/inflammatory cells/plaque fissures/ingrowth of blood vessels
Describe the cellular events leading to the formation of atherosclerotic lesions
1) Chronic endothelial injury
2) Lipid accumulation by LDL’s in the wall and formation of foam cells
3) Endothelium bulges due to accumulation of foam cells -> this is a fatty streak
4) SMC’s proliferation and formation of a fibrous plaque and a fibrous cap
5) Central necrosis of the plaque, small blood vessels grow into the plaque
6) Plaque injury resulting in thrombosis or haemorrhage
Distinguish between thrombosis and atherosclerosis
Atherosclerosis is the deposition of lipids in arterial walls
Thrombosis is a local solid blood clot in the circulatory system
What can make a plaque ‘complicated’?
Ulceration (exposure of the central plaque which is highly thrombogenic)/haemorrhage/thrombosis
How are foam cells formed?
Lipid accumulates in the intima, LDL’s are oxidised and ingested by macrophages -> formation of foam cells
What is the main difference between an early and late atheromatous plaque?
Inovlement of the tunic media
What are some local complications of atheroma?
Calcification/ulceration/rupture/thrombosis/aneurysm formation/downstream ischaemia/emobolism
Give the effects of severe atherosclerosis at the following sites:
- Iscahemic heart disease
- cerebral ischaemia
- mesenteric ischaemia
- peripheral vascular disease
- abdominal aortic -aenurysm
IHD - death/MI/angina/arrythmias/heart failure
Cerebral ischaemia - Stroke/multi-infarct dementia/TIA (transient ischaemic attack, brief episode of loss of neurological function)
Mesenteric ischaemia - malabsorption/intestinal infacrtion/ischaemic colitis
Peripheral vascular disease - intermittent claudication/Leriche syndrome (claudication in the buttocks due ot ischaemia)/gangrene/ischaemic rest pain
Abdominal aortic aneurysm - Exsanguination (bleeding out)/embolism
Give four major risk factors for atherosclerosis
Cigarette smoking/diabetes mellitus/alcohol/infection/hypertension/hyperlipidaemia/age/apoE genotype
Polymorphisms of which apolipoprotein are assoiated with high LDL levels?
ApoE
Familial hyperlipidaemia (main one is famililal hypercholesterolemia) is a genetic disorder characterised by naturally very high levels of LDL -> longer half life -> increased risk of fatty streak formation. What are some associated physical signs of this condition?
Corneal arcus/tendon xanthomas (tendon nodules)/xanthelasma (yellowed eyelids)
There is a protective effect against atherosclerosis in _______ women.
Menopausal
WHat infection causing bacteria are most atherosclerotic?
Chlamydia pneumoniae/Helicobacter pylori/Cytomegalovirus
Briefly describe the insudation theory of atherogenesis
NOTE you only need to understand the hypotheses not be able to quote them
endothelial injury -> inflammation -> increased permeabilty for lipids to enter the wall from the plasma
Briefly describe the reaction to injury hypothesis
plaques form in response to endothelial injury -> injury increases permeability -> ->SMC’s migrate in an proliferate
What is the monoclonal hypothesis?
Idea that each plaque is monoclonal and is an abnormal growth that might act like a benign tumour
Briefly explain the unifying hypothesis
Atherosclerosis is a result of endothelial injury due to rasied LDL, toxins, hypertension and haemodynamic stress
