Cardiology

Cannabinoids protect the heart

Cannabinoids have a protective effect on the heart when it’s been deprived of blood flow (ischemia), which can lead to infarctus, according to a study by Daniel Lamontagne, a full professor in the Faculty of Pharmacy at the Université de Montréal. Heart disease claims the lives of nearly 80,000 Canadians every year.

Lamontagne’s research term observed a reduction of more than 50% in the severity of infarctus in a rat perfused with cannabinoids.  Cannabinoids have a protective effect on the heart, says Lamontagne, Vice-Dean of Graduate Studies and Research for the Faculty. “It’s one of the natural protective mechanisms whereby the heart can protect itself from the deleterious effects of ischemia.”

Japanese researchers isolated the first cannabinoid receptor, located in the central nervous system, around 1990. “Then we began to identify substances produced by the human body that can stimulate these receptors and have physiological effects,” explains Lamontagne, who’s been working on endocannabinoids for the past six years. Since the discovery of the first endocannabinoid in the human brain, anandamid (from the Sanskrit word ananda, which means bliss), interest from the scientific community has continued to grow.

Cannabis has been known for its therapeutic uses for many millennia. For example, it can be used to prevent nausea in chemotherapy patients. But does that mean the principal active agent in marijuana, delta-9-tetrahydrocannabinol (THC), could have beneficial effects for the heart? “We can’t necessarily conclude that consuming cannabis would have a protective effect. When you smoke cannabis, you inhale a huge number of noxious substances, such as tar, which are harmful and can even reverse the effects,” says Lamontagne. “As I often tell my students, if nature endowed the human body with cannabinoid receptors it wasn’t just so you can smoke your joint on Saturday night.  It’s because there is an endogenous cannabis system that will act on those receptors and play a physiological function. ”

When basic research bears fruit the most interesting part is, of course, the clinical applications. “There’s many a slip ‘twixt the cup and the lip, since our experiments are performed on rats. Would we observe the same effects in humans? That remains to be shown,” warns Lamontagne. Clinical trials with human subjects are unlikely to start in the short term, so it’s too soon to envisage applications. “If there were eventually some applications, it would not be through cannabis consumption but via the administration of synthetic compounds,” Lamontagne points out.

In the meantime, other research pathways are opening up. Pierre Beaulieu, an associate professor in the Faculty of Medicine, is analyzing the analgesic effects of endocannabinoids. A colleague from the School of Optometry, Jean-François Bouchard, is working on how cannabis affects neurons. The endocannabinoid system, a relatively recent field of research, is starting to reveal its secrets.