High-density lipoprotein: Quality is more important than quantity!

High density lipoproteins (HDLs) are complex lipid carriers which replace their own structures and functions according to different conditions including healthy or pathological status. HDL has substantial roles in reverse cholesterol transport system for regulation of lipid metabolism. Also HDL has many functions such as antiinflammation, antioxidation, antithrombotic and vasodilator actions. However, these functions may be compromised under pathological conditions. Nowadays, it’s known that the function of HDL is more important than it’s dose for preventing against cardiovascular diseases. This review mostly summarizes available information of HDL structure, metabolism and the real information related to the physicochemical changes of HDLs causing their different functions. Also HDLs, that lost their protective functions have been associated with oxidative stress and systemic inflammation diseases.