Some VLDL's are further depleted of TG's and become LDL's. LDL receptors are an important regulator of cholesterol uptake. They are effective in extending the lives of those with hypercholesterolemia. How cholesterol is associated with heart disease is still not completely understood. LDL's are considered 'bad' cholesterol, while HDL's are considered 'good' cholesterol and there is some correlation with these levels and heart disease.
Cholesterol is transported in two forms - free cholesterol and esterified cholesterol .
HDL are synthesized in the liver and gut and engage in 'reverse cholesterol transport'. They transfer ApoE and ApoCII to VLDL and chylomicrons and pick up cholesterol from cholesterol-rich cells. HDL will esterify cholesterol via LCAT and transport cholesterol esters back to the liver and to tissues that make steroid hormones. They also transfer cholesterol esters to VLDL in exchange for TG's and will take back ApoCII, ApoE from VLDL remnants. HDL's thus scavenge cholesterol, preventing it from accumulating and doing damage.