A class of Lipoproteins of small size (4-13 nm) and dense (greater than 1.063 g/ml) particles. HDL Lipoproteins, synthesized in the liver without a lipid core, accumulate Cholesterol Esters from peripheral Tissues and transport them to the liver for re-utilization or elimination from the body (the reverse Cholesterol transport). Their major protein component is Apolipoprotein A-I. HDL also shuttle Apolipoproteins C and Apolipoproteins E to and from triglyceride-rich Lipoproteins during their catabolism. HDL Plasma level has been inversely correlated with the Risk of Cardiovascular Diseases.