Cholesterol question

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Phloston

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P. 120 of FA says, for HDL (to the right of the orange circle that says "mature HDL"): "transfer of cholesterol esters to VLDL, IDL, LDL."

HDL functions in reverse cholesterol transport (i.e. bringing it from the periphery to the liver [as specified on p. 121]), so why would it transfer cholesterol esters to LDL, considering LDL only brings cholesterol to the periphery?

Should p. 120 instead say "transfer of cholesterol esters to VLDL, IDL"?
 
P. 120 of FA says, for HDL (to the right of the orange circle that says "mature HDL"): "transfer of cholesterol esters to VLDL, IDL, LDL."

HDL functions in reverse cholesterol transport (i.e. bringing it from the periphery to the liver [as specified on p. 121]), so why would it transfer cholesterol esters to LDL, considering LDL only brings cholesterol to the periphery?

Should p. 120 instead say "transfer of cholesterol esters to VLDL, IDL"?


that's correct.
 
P. 120 of FA says, for HDL (to the right of the orange circle that says "mature HDL"): "transfer of cholesterol esters to VLDL, IDL, LDL."

HDL functions in reverse cholesterol transport (i.e. bringing it from the periphery to the liver [as specified on p. 121]), so why would it transfer cholesterol esters to LDL, considering LDL only brings cholesterol to the periphery?

Should p. 120 instead say "transfer of cholesterol esters to VLDL, IDL"?

I think FA is right. Two other important functions of HDL are to 1) collect and transfer cholesterol esters to LDL via CEPT and 2) esterify free cholesterol/cholesterol on the surface of LDL via Apo A-> LCAT. In both cases, HDL does so to sequester cholesterol in VLDL/IDL/LDL by esterifying them and thus making them more hydrophobic. Remember, free cholesterol is dangerous, because it can modify cell membrane fluidity (among other things).

Regarding 1): There's a whole class of drugs under development that inhibit CEPT for the very reason of keeping cholesterol esters out of LDL, where they can get 'stranded' if B-100 gets oxidized or glycosylated. They also seem to increase HDL, probably by a removal of inhibition effect.

http://www.nejm.org/doi/full/10.1056/NEJMe078029
 
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