(V)LDL transports Cholesterol in blood vessels where it’s needed. It is often called the bad Cholesterol.HDL  is able to catch unneeded Cholesterol and is able to reduce the danger of arteriosclerosis.In the liver Cholesterol and fat is produced and transported to the cells as VLDL. In the blood vessels VLDL becomes LDL. Cholesterol is needed to produce hormones and cell membranesLDL can release Cholesterol to the cells.HDL takes unneeded Cholesterol. So the danger of arteriosclerosis is lower. Fully loaded HDL transfers Cholesterol to empty LDL which brings it to the liver where it is modified to gall for the gall bladder / intestine.

Anatomy of the heart