Regular stoners may be at increased risk of developing heart disease or having a heart attack, according to a new study published in the journal Cell. Researchers found that smoking a joint causes a rapid rise in pro-inflammatory compounds that can damage blood vessels, but a molecule in soy can help alleviate this damage.
Despite the growing interest in medical cannabis, the effects of the drug on cardiovascular health are largely unknown. To clarify the matter, the study authors analyzed the medical records of 157,331 people in the UK, including 34,878 who admitted to using cannabis.
Of these, 11,914 claimed to take the drug more than once a month. Overall, these monthly users were 16 percent more likely to have had a heart attack and were also more susceptible to premature heart attacks before the age of 50.
Delving a little deeper, the researchers analyzed blood samples from 18 people immediately after smoking a joint and found that pro-inflammatory cytokines increased within 90 minutes. These compounds are strongly implicated in atherosclerosis, the thickening of blood vessel walls due to the buildup of fatty plaques.
After applying THC, the psychoactive ingredient in cannabis, to isolated human endothelial cells, the authors found that the compound also suppressed antioxidant genes, further contributing to inflammation within the lining of blood vessels.
Commenting on these findings, study author Mark Chandy explained that “as more states legalize marijuana use, I expect we’ll start to see an increase in heart attacks and strokes in the next few years,” and He added that “THC exposure initiates a damaging molecular cascade in the blood vessels.”
The researchers discovered that the negative effects of THC on blood vessels are mediated by the cannabinoid receptor 1 (CB1). Researchers have tried to counteract the activity of THC using CB1 antagonists, which block the receptor, although most of these compounds are not suitable for use due to their psychiatric side effects.
However, using machine learning techniques to analyze a large database of CB1 antagonists, a compound called genistein was identified as a possible solution to the cardiovascular problems caused by THC. Genistein, found in soy, has a very limited ability to penetrate the brain, which means it shouldn’t produce any of the harmful side effects associated with other CB1 blockers.
To investigate the compound’s efficacy, the team fed mice that had been bred to have high cholesterol a high-fat diet. Adding a standard dose of THC to the rodents’ diets caused them to develop larger plaques inside their blood vessels, but treatment with genistein prevented this increase in plaque size.
“We did not see any blocking of the normal analgesic or sedative effects of THC in the mice that contribute to marijuana’s potentially useful medicinal properties,” Chandy said. “So genistein is potentially a safer drug than previous CB1 antagonists. It’s already used as a nutritional supplement and 99% of it stays outside the brain, so it shouldn’t cause these particular adverse side effects.”
While the use of THC and genistein has yet to be tested in humans, the researchers suggest that this combination may allow medical cannabis users to continue to enjoy the beneficial effects of the drug without increasing their susceptibility to heart disease.