9 - Vascular Endothelium 2 Flashcards
What stresses activate the endothelium?
- mechanical stress
- inflammation
- high BP
- smoking viruses
- oxLDL
- high glucose
What are the functions of endothelial cells?
- angiogenesis
- thrombosis and haemostasis
- inflammation
- vascular tone permeability
What is the resting state of endothelial cells?
- anti-inflammatory
- anti-thrombotic
- anti-proliferative
What is the activated state of endothelial cells?
- pro-inflammatory
- pro-thrombotic
- pro-proliferative
What are the risk factors of increased vascular permeability?
- smoking
- raised BP
- dyslipidaemia (abnormal amounts of lipids)
How are foam cells formed?
- lipoproteins get through endothelium and bind to proteoglycans
- lipoproteins oxidised
- macrophages gobble up oxidised lipoproteins and form a foam cell
What is atherosclerosis?
inflammatory disease of arteries in response to injury
What are the three main pathogenetic stages of atherosclerosis?
- endothelial dysfunction
- fatty streak formation
- formation of advanced complicated lesion
What are the features of endothelial dysfunction in atherosclerosis?
- increased endothelial permeability to lipoproteins
- leukocyte migration to artery wall
- up-regulation of endothelial adhesion molecules
- up-regulation of leukocyte adhesion molecules
What are the features of fatty streak formation in atherosclerosis?
- smooth muscle migration
- foam cell formation
- t-cell activation
- platelet adherence and aggregation
- leukocyte adherence and entry
What are the features of the formation of an advanced complicated lesion of atherosclerosis?
- macrophage accumulation
- formation of necrotic core
- fibrous-cap formation
- senescence and angiogenesis
What is the process of leukocyte recruitment in atherosclerosis?
during inflammation:
- leukocyte adheres to endothelium of post-capillary venules
- transmigrate into tissues (using enzymes to leave vessel)
in atherosclerosis:
- leukocytes adhere to activated endothelium of large arteries
- get stuck in sub-endothelial space
What does laminar flow promote?
- anti-thrombotic and anti-inflammatory factors
- NO production
- inhibition of SMC proliferation
What does turbulent flow promotes?
- coagulation
- leukocyte adhesion
- SMC proliferation
- endothelial apoptosis
- reduced NO production
What does laminar flow downregulate?
- expression of DNA methyltransferases
- promoter of antiatherogenic genes remain demethylated
- genes expressed