[Physical state of lipids accumulated in atherosclerotic lesions (author's transl)]

The work of Small and al. concerning the physical state of lipids accumulated in atherosclerotic plaques, is analysed. This team of biophysicists studies the composition in cholesterol, cholesterol esters and phospholipids, of each type of lesion and reports it on a phase diagram, while identifying the physical state of these lipids by polarizing microscope and by X-ray diffraction. In such a way, they show that the ordinary fatty streak has a composition which situates it in the 2 phases-zone, and actually demonstrate liquid crystals of phospholipids (+ cholesterol + cholesterol esters) and oily droplets of cholesterol esters, but never cholesterol crystals. In the other types of lesions (intermediary lesions, fibrous plaques and atheromatous plaques) they find, in addition to liquid crystals and oily droplets previously mentioned, crystals of cholesterol monohydrate, which leads to 3 phases. These findings are in accord with experimental models studied by the authors, for whom the physical state of lipids plays a very important role in the formation as well as the regression of atherosclerotic plaques.