Session 6 - Atherosclerosis Flashcards
Define atheroma
Accumulation of Intracellular and extracellular lipid in the intima and media of medium and larger sized vessels
Define Arteriosclerosis
The thickening of walls of arteries and arterioles, usually as a result of hypertension or Diabetes Mellitus
Describe the cellar events leading to the formation of atherosclerotic lesions
- damage to endothelial cells
- platelets adhere, release PDGF -> causes proliferation and migration of smooth muscle cells
- SMC go into intima, take up LDLs -> become foam cells
- monocytes -> macrophages -> take up LDL -> foam cells
- SMC produce collagen and ECF
Name some macroscopic morphological appearances of atherosclerosis
- Fatty Streak: lipid deposits in intima , yellow slightly raised
- Simple Plaque: Raised irregular, yellow white - can enlarge and coalesce
- Complicated Plaque: Some thrombosis, haemorrhage into plaque, calcification and aneurysm formation
Name some microscopic morphological appearances of atherosclerosis
- Early changes: proliferation of SMC, accumulation of foam cells, extracellular lipid
- Later changes: Fibrosis, Necrosis, cholesterol clefts, inflammatory cells
Name some common sites of atherosclerosis
- Aorta - especially abdominal aorta
- coronary arteries
- carotid arteries
- cerebral arteries
- leg arteries
Name some effects of Ischaemic heart disease
- Sudden death
- MI
- Angina pectoris
- Arrythmias
- Cardiac Failure
Name some effects of Cerebral Ischaemia
- transient Ischaemic attack (Infaraction of part of brain - symptoms for 24 hrs)
- cerebral infarction (stroke)
- multi-infarct dementia
Name some Mesenteric Ischaemia
- Ischaemic colitis (inflammation and injury to large intestine)
- malabsorption
- intestinal infarction
- aneurysm due to increased pressure, hardening and weakening
Name some Peripheral vascular disease effects
- intermittent claudication
- Leriche syndrome
- Ischaemic rest pain (intermittent claudication in iliac artery -> gluteal pain)
- Gangrene
Describe the reaction to injury/insulation theory
- endothelial injury leading to inflammation
- Increased permeability to lipid and platelet adhesion
- monocytes penetrate
- smooth muscle proliferation + migration
Describe the monoclonal hypothesis
- each plaque is monoclonal
- smooth muscle proliferation is crucial
- abnormal growth control
- each plaque is a benign tumour?
- atheroma may have viral epidemiology
Describe the thrombogenic theory
- plaques form by repeated thrombi
- lipids are from thrombi
- overlying fibrous cap
Describe the Unifying Hypothesis
- endothelial injury due to- raised LDL, toxins, hypertension
- leads to platelet adhesion, PDGF release, SMC proliferation
- insulation of lipid -> uptaken by SMC and macrophages
- monocytes migrate into intima
- SMC produce matrix material
- foam cells secrete cytotoxins: further SMC stimulation
List the risk factors for atherosclerosis
- Smoking - Excessive alcohol intake
- Hypertension - Apolipoprotein E genotype
- Impaired glucose tolerance - Familial Hyperlipidaemia
- Age - Infection
- Gender (male)
- Hyperlipidaemia
