Why the HDL-Cholessterin is the "good" one

The importance of the role of HDL cholesterol further elucidated

Even laypeople now know that a high concentration of blood lipids (cholesterol) means a risk for vascular diseases, especially heart attacks and strokes. However, high blood cholesterol alone says little about the dangers. Rather, it is the individual fractions of blood lipids that are decisive: it turned out years ago that the so-called HDL cholesterol is not dangerous;

Why, however, has remained largely unclear so far. Now a group of scientists from Münster, Düsseldorf, Essen, Tokyo and Berlin, in which Professor Dr. Markus van der Giet from the "Medical Clinic IV" of the Charité played a major role in the solution to the riddle: The group found that HDL is a decisive regulator of the so-called vascular tone, the narrowing or widening of blood vessels. HDL stimulates the formation and release of the volatile gas nitrogen monoxide (NO) from the endothelial cells, the cells that form the inner lining of the blood vessels. HDL binds to the corresponding receptor in the wall of these cells. As soon as NO is released from it, the muscle cells in the deeper layers of the vascular wall relax and the vascular clearing expands.

If, on the other hand, there is a lack of HDL, then relatively too little NO is formed: there is no relaxation of the vessels. In the long run, the vessel wall then changes: immune cells grow in, the formation of thrombi is paved, and arteriosclerosis paves the way. The researchers also realized that the entire HDL molecule is not responsible for the release of NO. Rather, its vascular-active effects can be achieved through three of its components, the so-called lysophospholipids S1P, SPC and LSF, and with each one individually. These substances should therefore be interesting objects for the pharmaceutical industry, for example for combating arteriosclerosis. The scientists found the connections between HDL and N0 in isolated arteries but also in animals (rats and mice) and published their findings today, February 16, in the renowned journal "The Journal of Clinical Investigation" (Nofer J.-R., van der Giet, M et al 113 [2004] 569-581).

(The discovery that NO is the substance in the endothelial cells of the vessel wall that causes the vessel to relax was what brought Professor Louis Ignarro from Los Angeles the Nobel Prize in 1998. Now we know another important substance that is responsible for the formation of NO: HDL cholesterol.)

Source: Berlin [ Charité ]