phytoesterogens

Question 1

phytoestrogens

Answer 1

plant derived compounds, mimic estrogen at specific sites in the body

Question 2

phytoestrogen in bones

Answer 2

decrease bone resorption and delay osteoporosis progression

Question 3

aglycones

Answer 3

phytoestrogen after removal of sugar group, active form
cleaved after ingestion

Question 4

estrogen receptors

Answer 4

ERa and ERB
facilitate actions at the level of DNA transcription and signaling cascades

ERa: uterus, vagina, ovaries, mammary gland, hypothalamus

ERB: prostate and ovaries, lungs brain bones

bind phytoestrogens

Question 5

estradiol (E2)

Answer 5

natural estrogen
phenolic A ring responsible for selective high-affinity binding to ER

phytoestrogens have lower affinity but higher concentration than natural estrogen

shown to promote vascular relaxation

Question 6

vasodilators

Answer 6

NO, prostaglandin I2 (PGI2)

Question 7

vasoconstrictors

Answer 7

angiotensin II, endothelin (ET)

Question 8

phytoestrogen and Ca+ mechanism

Answer 8

phytoestrogens stimulate NO, which triggers the removal of Ca2+ in VSM cells through pumps > muscle relaxation and vasodilation

also through PGI2-cAMP-PKA pathway > removal of Ca2+

Question 9

mechanisms in which phytoestrogens affect vascular smooth muscle (also applies to epicatechin)

Answer 9

1) Ca2+/calmodulin pathway
2) PI3K/AKT pathway

Both activate eNOS

Question 10

phytoestrogens have shown to inhibit osteoclastogenesis

Answer 10

inhibit bone resorption

Question 11

ET-1

Answer 11

causes Ca2+ influx into VSM, vasoconstriction
inhibited by phytoestrogens

Question 12

osteoblast vs osteoclasts

Answer 12

bone forming vs bone resorbing (break down bone tissue)

Question 13

RANKL

Answer 13

produced in osteoblasts, binds to osteoclasts
induces osteoclastogenesis
activates MAPK, AKT, NFkB downstream

Question 14

BMPs (Bone morphogenetic proteins)

Answer 14

critical in osteogenesis
stimulates transcription factors Runx2 and Smads (facilitates differentiation to osteoblasts)

BMP-activated MAPKs and Smads control MSCs differentiation through Runx2

Question 15

how do osteoclasts develop??

Answer 15

RANKL > MAPKs > NFkB activation > osteoclasts development and proliferation

Question 15

how do phytoestrogens promote bone growth?

Answer 15

upregulate the BMP/Smad/Runx2 signaling pathway

Question 16

how do phytoestrogens inhibit pro-osteoclast signaling?

Answer 16

inhibiting RANKL/NFkB mediated activation of osteoclasts

Question 17

Phytoestrogen and epicatechin have two common proposed pathways by which they reduce blood pressure. Briefly, what are they?

Answer 17

1) Activation of eNOS via PI3K/AKT pathway

2) Activation of eNOS via Ca2+
Phytoestrogens release NO in vascular smooth muscle → decrease of Ca2+ in VSM via uptake pumps → VSM relaxation, vasodilation
Epicatechin triggers an increase in intracellular Ca2+, increase in calmodulin → eNOS activation