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18 Cards in this Set
- Front
- Back
what is the process of vascular remodeling in embryonic life?
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- vascular endothelial cell progenitors (angioblasts) --> differentiate & turn into vascular plexus (vasculogenesis)
- early embryonic vasculature then grows by budding (angiogenesis) & by recruiting mural cells (including pericytes & vascular smooth muscle cells) |
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what are mural cells?
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- pericytes or smooth muscle cells
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what are some steps in microvascular maturation?
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growth factor production --> endothelial activation --> changes in permeability --> extracellular remodeling --> pericyte recruitment --> endothelial cell migration --> cell proliferation & lumen formation --> blood flow initiation --> sprouting/angiogenesis
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what is angiogenesis vs vasculogenesis?
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- angiogenesis is budding of new vessel from pre-existing vasculature
- vasculogenesis is de novo formation of new blood vessels from angiobastic precursor during development |
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where does angiogenesis mainly occur from?
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- from the venues
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from looking at a vessel can you tell if it is from vasculogenesis or angiogenesis?
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- no
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what is the difference in endothelial-pericyte interactions in physiologic vs pathologic states?
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- the pericytes are hypercontractile in pathologic states & there is a loss of growth arrest
- normally perictyes have normal basal tone & there is contact-mediated growth arrest |
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what is the difference in acute vs chronic wound healing in terms of angiogenesis?
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- in chronic wound healing there is an inability to recruit progenitors from bone marrow
- healing may takes weeks or years, there is insufficient proliferation, delayed epithelial migration, too much inflammation - basically re epithelialization is retarded in chronic wounds, depressed growth factors, elevated MMPs - impaired angiogenesis |
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what happens in the angiogenesis of wound healing & tumor growth?
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- mother vessels evolve into daughter vessels
- mother vessels bridge they break off into daughter capillaries |
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daughter capillaries arise from mother vessels by what mechanism?
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- internal bridging
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what is the angiogenic switch?
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- blood vessels that are quiescent turn into ones that are actively growing
- basically vascular endothelial cells are stimulated to proliferate |
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tumors are only detectable after what?
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- after the angiogenic switch because then they can grow >2mm
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are all human tumor cells angiogenic?
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- no
- human tumors contain angiogenic & non-angiogenic tumor cells |
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what is the effect of the primary tumor on metastases?
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- when the primary tumor is removed, micrometastases begin growing
- primary tumor alone can inhibitor growth & development of secondary metastases via inhibition of angiogenesis |
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what are two angiogenesis inhibitors secreted by primary tumors?
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1) angiostatin (plasminogen cleavage product)
2) endostatin (collagen XVIII cleavage product) |
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what do pericytes control in the capillary?
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- permeability, growth & contractility
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diabetics have a problem with angiogenesis however what is diabetic retinopathy?
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- however in diabetics there is retinal circulation proliferation
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what is age-related macular degeneration?
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- coroidal microvasculature switches from quiescent endothelium to rapidly growing one
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