Microvascular Physiology

Question 1

What is vascular morphogenesis?

Answer 1

Vascular remodeling

Question 2

Does vascular remodeling occur physiologically throughout a person’s life?

Answer 2

Yeah

Question 3

Can vascular morphogenesis be pathologic?

Answer 3

Yeah

Question 4

What is the difference between angiogenesis and vasculogenesis?

Answer 4

Angiogenesis is the formation/budding of new blood vessels from preexisting vasculature, whereas vasculogenesis is de novo blood vessel formation from angioblastic precursor cells.

Question 5

During vasculogenesis, a _______ microvessel is first formed, after which _______ cells are recruited, forming a stable vessel.

Answer 5

unstable microvessel forms first, then mural cells are recruited, forming a stable vessel.

Question 6

Are endothelial cells heterogeneic?

Answer 6

Yeah!

Question 7

Name the ten steps in microvascular maturation/remodeling.

Answer 7

1. GF (VEGF) production/release by vascular and non-vascular associating cells.
2. Endothelial cell activation.
3. Changes in microvascular permeability.
4. ECM remodeling.
5. Pericyte recruitment.
6. Endothelial cell migration.
7. Cell proliferation/division.
8. Lumen formation.
9. Initiation of blood flow.
10. Sprouting/angiogenesis.

Question 8

How does lumen formation occur?

Answer 8

Dunno!

Question 9

Does blood flow only once a lumen is formed?

Answer 9

Yeah

Question 10

Research has shown that primary tumors _____ the growth of secondary metastases.

Answer 10

inhibit

Question 11

What is a cryptic angiogenesis inhibitor? Name two examples.

Answer 11

The angiogenic inhibitors released by primary tumors. Examples are angiostatin (a cleavage product of plasminogen), and endostatin (a cleavage product of collagen 18).

Question 12

How do tumor cells make angiostatin and endostatin?

Answer 12

They release a protease that cleaves plasminogen and collagen 18 to give rise to the angiogenesis inhibitors.

Question 13

What are mural cells?

Answer 13

Supporting cells like pericytes and smooth muscle cells.

Question 14

What three things can pericytes control?

Answer 14

Vascular permeability, growth, and contractility.

Question 15

Amongst different vessel types, the pericyte : endothelial cell ratio is highly ______.

Answer 15

variable

Question 16

Recruitment of ______ cells is largely responsible in stabilizing a newly formed microvessel.

Answer 16

mural

Question 17

What does ischemia/hypoxic insult do to endothelial cells?

Answer 17

It triggers VEGF gene transcription, leading to VEGF protein production –> angiogenic response by endothelial cells.

Question 18

Do most of us have unknown, dormant microscopic avascular lesions (avascular micrometastatic lesions) in our bodies?

Answer 18

Yeah

Question 19

Mechanical deformation of an endothelial cell by a pericyte can push the endothelial cell out of quiescence and into the _______ cycle.

Answer 19

growth

Question 20

In diabetic retinopathy there is increased _________ in the retina.

Answer 20

angiogenesis

Question 21

Plantar ulcers in diabetics are largely due to _______ angiogenesis.

Answer 21

impaired

Question 22

The ________ switch aids greatly in the generation of an invasive cancer from a microscopic, avascular tumor.

Answer 22

angiogenic

Question 23

What is the difference between angiogenesis in diabetic retinopathy and age-related macular degeneration?

Answer 23

In diabetic retinopathy angiogenesis occurs in the retina, which hemorrhage, causing bind spots in the patient’s field of vision. In AMD, angiogenesis occurs in the choroid plexus behind the eye: endothelial cells invade though the sclera, through Bruch’s membrane, and disturb the macula –> loss of central field of vision.