Physiology Lec 11 - Microvascular

Front 1

what is the process of vascular remodeling in embryonic life?

Back 1

- 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)

Front 2

what are mural cells?

Back 2

- pericytes or smooth muscle cells

Front 3

what are some steps in microvascular maturation?

Back 3

growth factor production --> endothelial activation --> changes in permeability --> extracellular remodeling --> pericyte recruitment --> endothelial cell migration --> cell proliferation & lumen formation --> blood flow initiation --> sprouting/angiogenesis

Front 4

what is angiogenesis vs vasculogenesis?

Back 4

- angiogenesis is budding of new vessel from pre-existing vasculature

- vasculogenesis is de novo formation of new blood vessels from angiobastic precursor during development

Front 5

where does angiogenesis mainly occur from?

Back 5

- from the venues

Front 6

from looking at a vessel can you tell if it is from vasculogenesis or angiogenesis?

Back 6

- no

Front 7

what is the difference in endothelial-pericyte interactions in physiologic vs pathologic states?

Back 7

- 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

Front 8

what is the difference in acute vs chronic wound healing in terms of angiogenesis?

Back 8

- 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

Front 9

what happens in the angiogenesis of wound healing & tumor growth?

Back 9

- mother vessels evolve into daughter vessels

- mother vessels bridge they break off into daughter capillaries

Front 10

daughter capillaries arise from mother vessels by what mechanism?

Back 10

- internal bridging

Front 11

what is the angiogenic switch?

Back 11

- blood vessels that are quiescent turn into ones that are actively growing

- basically vascular endothelial cells are stimulated to proliferate

Front 12

tumors are only detectable after what?

Back 12

- after the angiogenic switch because then they can grow >2mm

Front 13

are all human tumor cells angiogenic?

Back 13

- no

- human tumors contain angiogenic & non-angiogenic tumor cells

Front 14

what is the effect of the primary tumor on metastases?

Back 14

- when the primary tumor is removed, micrometastases begin growing

- primary tumor alone can inhibitor growth & development of secondary metastases via inhibition of angiogenesis

Front 15

what are two angiogenesis inhibitors secreted by primary tumors?

Back 15

1) angiostatin (plasminogen cleavage product)

2) endostatin (collagen XVIII cleavage product)

Front 16

what do pericytes control in the capillary?

Back 16

- permeability, growth & contractility

Front 17

diabetics have a problem with angiogenesis however what is diabetic retinopathy?

Back 17

- however in diabetics there is retinal circulation proliferation

Front 18

what is age-related macular degeneration?

Back 18

- coroidal microvasculature switches from quiescent endothelium to rapidly growing one