symbioidlj | from arstechnica (Reply)

Heart attacks. Cardiovascular disease. Atherosclerosis. We hear these words everyday, even if, unlike me, you don't work in the field. That's because this growing epidemic is responsible for so many deaths each year in industrialised nations. A combination of our diet, habits like smoking, not exercising enough, gum disease, industrial pollutants and genetics are combining to cause the greatest cause of death for men and women.

Scarcely a day goes by when another item is added to the list we mentally keeped taped to the fridge, entitled "More things that will kill me." Less frequently, items get added to the other list, "things that might keep me alive." Recently, it was announced that a compound in red wine, resveratrol, could be beneficial in warding off heart disease. Now we might be able to add its less socially-accepted colleague, cannabis (subscription required).

THC, one of the active ingredients in cannabis, acts on a family of receptors called CB receptors. There are two subclasses of CB receptor, CB1 and CB2. CB1 receptors are present in blood vessels, amongst other tissues, and they cause blood vessels to dilate. The role of CB2 receptors is less well understood, but they are expressed on circulating immune cells like macrophages.

These cells are critically important in many inflammatory auto-immune diseases, and in atherosclerosis the disease is driven by the recruitment of circulating macrophages into the wall of the blood vessel, where they take up deposits of cholesterol and lipids. Steffens et al. have shown that adding THC reduces the development of atherosclerosis in mice, and that activation of the CB2 receptor by THC affects their activation and recruitment to the plaque.

Now at this point I ought to point out that smoking cannabis isn't necessarily going to be beneficial for you — the sedentary life style, the hypotension, and the fact that smoking anything is bad for the lungs and circulation. It is possible that we will see drugs targeting CB2 receptors being developed however, as oral or transdermal administration are both better routes of administration.