HDL serves as a chemical shuttle that transports excess cholesterol from peripheral tissues to the liver. This pathway is called the RCT system. In this system, plasma HDL takes up cholesterol from the peripheral tissues, such as fibroblasts and macrophages. (A study by El Khoury et al indicated that in persons with HALP, macrophages have an increased plasma cholesterol efflux capacity.  ) This may occur by passive diffusion or may be mediated by the adenosine triphosphate (ATP)–binding cassette transporter 1. The latter interacts directly with free apo A-I, generating nascent, or so-called discoidal, HDL. Cholesterol undergoes esterification by lecithin-cholesterol acyltransferase (LCAT) to produce cholesteryl ester, which results in the production of the mature spherical HDL. Cholesterol is also taken up from triglyceride-rich lipoproteins in a process mediated by a phospholipid transfer protein (ie, CETP). [19, 20, 21, 22]
Cholesterol is then returned to the liver by multiple routes. In the first route, cholesterol esters may be transferred from HDL to the apo B–containing lipoproteins, such as very–low-density lipoprotein (VLDL) or intermediate-density lipoprotein (IDL), by CETP. These lipoproteins undergo metabolism and subsequent uptake by the liver, primarily by a process mediated by the B,E receptor. In the second route, HDL particles may be taken up directly by the liver. In the third, free cholesterol may be taken up directly by the liver. Finally, HDL cholesterol esters may be selectively taken up via the scavenger receptor SR-B1.
It’s about time you figure out how to eat this darn thing, because an artichoke is a heart-healthy powerhouse that may help raise levels of HDL, according to research published in the journal International Journal of Food Sciences and Nutrition! With about 10.3 grams of fiber per each boiled head, this makes artichoke one of the highest fiber vegetables in the entire produce aisle.