Biology 11th Edition by Cecie Starr ,Ralph Taggart

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Cholesterol from food or synthesized in the liver is too hydrophobic to circulate in blood; complexes of protein and lipids ferry it around. Low density lipoprotein, or LDL , transports cholesterol out of the liver and into cells.
High density lipoprotein, or HDL , ferries the cholesterol that is released from dead cells back to the liver.
High LDL levels are implicated in atherosclerosis, heart problems, and strokes. The main protein in LDL is called ApoA1. A mutant form of ApoA1 has the wrong amino acid (cysteine instead of arginine) at one place in its primary sequence. Carriers of this LDL mutation have very low levels of HDL, which is typically predictive of heart disease. Yet the carriers have no heart problems.
Some heart patients received injections of the mutant LDL, which acted like a drain cleaner. It quickly reduced the size of cholesterol deposits in the patients arteries.
A few years from now, such a treatment may reverse years of damage. However, many researchers caution that a low-fat, low-cholesterol diet is still the best assurance of long-term health. Would you choose artery-cleansing treatments over a healthy diet