For their investigations, the researchers used a test consisting of a collagen matrix covered with endothelial cells. The researchers applied a nutrient solution of human plasma to this layer together with monocytes that they had isolated from the blood of volunteers.

After 48 hours, they examined how many monocytes, transformed into macrophages, had migrated into the collagen layer and how many of them had turned into foam cells - storage sites for LDL cholesterol and thus starting points for the formation of atherosclerosis. There were far fewer in subjects who had smoked e-cigarettes.

Source:
https://www.aerzteblatt.de/news/e-zigaretten-fordern-atherosklerose-weniger-stark-als-tabakzigaretten-dbfff4fe-34b9-482a-8f7e-ecdb4b9eb57d