Vascular Remodelling Flashcards
Layers of vessel
Tunica externa
Tunica media
Tunica intima
Tunica externa of artery
vasa vasorum
nervi vasorum
Tunica media of artery
external elastic membrane
smooth muscle
elastic fibre
Tunica intima of artery
internal elastic membrane
endothelium
tunica externa of vein
vasa vasorum
smooth muscle
tunica media of vein
smooth muscle
tunica intima of vein
endothelium
Features of endothelial cells
main cellular component of blood vessels vessel wall homeostasis non-thrombogenic interface vascular resistance metabolise hormones regulate inflammation affect growth of other cells tight endothelial junctions
4 endothelial cell functions
haemostatic functions
barrier + transduction functions
control of vascular wall functions
leukocyte/endothelial cell adhesive function
Haemostatic functions of endothelial cells
Provide TF = encourage clot formation
PROTHROMBOTIC MOLECULES - VWF/TF/Plasminogen activator inhibitor
Barrier + transducing functions of endothelial cells
maintenance of permeability + regulation of cell growth
- stimulator
Control of vascular wall functions endothelial cells
vasoconstrictors = endothelin/ ACE
vasodilator - NO/ Prostacyclin
Leukocyte/endothelial cell adhesive function - endothelial cells
regulation of inflammation + immunity
chemokines + adhesion molecules
Intimal thickening process
1) migration (+ proliferation) of smooth muscle cells to intima
2) smooth muscle mitosis
3) elaboration of extracellular matrix
endothelial activation - types
inflammation - cytokines/bacteria
atherosclerosis - haemodynamic stress/lipids
diabetes - glycosylation end products
result of endothelial activation
production of cytokines/growth factors + vasoactive molecules
affect vasoreactivity of smooth muscle
- relax (NO) + contract (endothelin)
endothelial dysfunction
altered phenotype impairs vasoreactivity + induces thrombogenic surface/ abnormally adhesive to inflammatory cells
thrombus + atherosclerosis + vascular lesions of hypertension
Inflammation
1) adhesion to monocytes + T cells
2) adhere + migrate to intima
3) macrophages engulf lipoproteins
3) activated macrophages
4) smooth muscle cell proliferation
5) T cells activated inflammatory cytokines
6) stimulate macrophages + EC + smooth muscle
7) growth factor release + smooth muscle proliferation + extracellular matrix synthesis
Vascular remodelling definition
active process of structural change
- cell growth/cell death/cell migration + synthesis or degradation of extracellular matrix
- can contribute to vascular disease
remodelling in hypertension
increased width to lumen ratio
remodelling due to aneurysm
cell loss/matrix proteolysis
Remodelling process
changes in haemodynamic conditions
relay of signal within and in adjacent cells
synthesis/release of cell growth/death/migration substances
structural changes in vessel wall
Saccular aneurysm
TRUE
one sided
- intact wall
Fusiform aneurysm
TRUE
2 sided
intact wall
False aneurysm
wall defect - blood through defect to media and adventitia
causes - haematoma + dilation
Dissecting aneurysm
dual flow - intima/media
blood enters through wall - defect in intima = creates turbulent flow
HAEMATOMA
vasa vasorum can’t reach endothelial cells
Aneurysm definition
localised abnormal dilation of a blood vessel or the heart
- congenital or acquired
Cause of aneurysm in ascending aorta
hypertension
