Cannabis may help keep arteries clear

The New Scientist

Eating low doses of THC, the active ingredient in cannabis, helps prevent arteries clogging up, at least in mice.

THC binds to two receptors in the body. One is found mostly on brain cells and is responsible for the chemical's psychotropic effects. The other receptor is found mostly on immune cells, and THC has been shown to suppress the immune response to infections and cancer.

François Mach at University Hospital in Geneva, Switzerland, wondered if this effect might also help prevent the build-up of fatty deposits in arteries, or atherosclerosis, by reducing the inflammation associated with this process. Sure enough, when his team fed 1 milligram of THC per kilogram of bodyweight - a low dose that should not have any psychotropic effects - to mice susceptible to atherosclerosis, it greatly slowed the progress of the disease (Nature, vol 434, p 782).

The results are striking, says Michael Roth of the University of California, Los Angeles, who wrote a commentary for Nature. He stresses that the findings do not prove that smoking cannabis will prevent atherosclerosis, pointing out that the mouse study suggests the effect is dose-dependent and too little or too much THC has no protective effect.

Rather than feeding people THC, Roth says, researchers should try to develop drugs that bind only to the cannabinoid receptor found on immune cells.