Home News Concordia master’s student studies the effects of cannabinoids on the immune system

Concordia master’s student studies the effects of cannabinoids on the immune system

by Marissa Ramnanan October 15, 2019
Concordia master’s student studies the effects of cannabinoids on the immune system

It’s been a year since cannabis has been legalized in Canada, and the drug is being widely used across the country.

In the second quarter of 2019 alone, Statistics Canada reported that almost 5 million Canadians have reported using cannabis. Since it was only recently legalized, there hasn’t been much research on it or the effects it has on users.

“So many people are using it, so how do we not know exactly what it’s doing to our bodies?” Concordia Psychology MA student, Norhan Mehrez asked. She said it was shocking to her that we still don’t fully understand the mechanism behind some of its effects.

Due to this lag in research, Mehrez said she took it upon herself to study the effects of cannabinoids on people, with a focus on the immune system.

Mehrez’s research is an intersection of three fields: the immune system, circadian rhythms and cannabinoids (THC, CDB and synthetic cannabinoids).

With the help of co-supervisors Shimon Amir, from the department of psychology, and Peter Darlington, an associate professor in the Department of Health, Kinesiology and Applied Physiology, Mehrez aims to understand how cannabinoids affect timekeeping in the immune system.

“We know it affects the immune system in several ways, we know that it may affect timekeeping in different tissues in the body,” said Mehrez. “I’m expecting that [cannabinoids] play some sort of role in maintaining an optimal balance in immune function. We know that cannabinoids affect the immune system, but the actual mechanisms of how it’s having those effects isn’t fully understood.”

The link between circadian rhythms and immune system

Circadian rhythms are the 24-hour cycles in the body that regulate different organs and functions. An example of this is the sleep-wake cycle, which repeats every 24 hours. Mehrez explained we have circadian rhythms in a lot of functions of the body, including the immune system. We also have genes, called clock genes, that ensure the regulation of the circadian rhythm of certain functions, depending on the body’s perceived time of day. The clock genes “keep time” by rhythmically activating along a 24-hour cycle, which in turn leads to rhythms in many bodily processes.

Mehrez explained your immune system seems to function optimally at certain times of the day, where your immune response to fight a pathogen is the strongest, and where you may be more likely to heal from a wound. This is where the immune system and circadian rhythms are tightly linked.

Mehrez said when a person’s sleep-wake cycle is disrupted by working the night shift for example, this also affects other circadian rhythms in the body. Those workers are more likely to develop disorders of the immune system because their time keeping is thrown off.

“On the other hand, if you compromise the immune system in animals or in people, we see that some of their circadian rhythms get disrupted as well,” Mehrez continued.

The link between circadian rhythms and the immune system has been recently investigated, though research is still being done. Mehrez said she wants to learn how cannabinoids affect the immune system as it keeps time.


Mehrez got funding from the Natural Sciences and Engineering Research Council of Canada for her research. She said they recruit healthy participants and screen them to have normal sleep cycles by using different questionnaires. They also have questionnaires to understand their drug habits. The participants’ blood is taken from them once screened and Mehrez then isolates the T cells, a subtype of white blood cells that detects the presence of a foreign invader in the body and creates an immune response to attack it.

Mehrez adds different cannabinoids to the isolated T cells, such as THC, CBD and synthetic cannabinoids, activates the T cells to stimulate an immune response and measures the reaction of the cells every four hours, for 36 hours.

They also look at the expression of the clock genes, which continue to show rhythms for some time even after being removed from the body. Once the researchers activate the T cells and add cannabinoids, they will see whether the cannabinoids affect clock genes and rhythmicity in the T cells.

“Are the cannabinoids going to help cells go back to normal time keeping or are they going to make time keeping worse? We don’t know,” said Mehrez.

Mehrez said, through her research, her team is hoping to uncover whether cannabinoids will help maintain normal time keeping under conditions known to disrupt it or if it will they cause further disruption.

There is a system in the body that has receptors for cannabinoids, generally involved in maintaining balance. For example, maintaining a body temperature of 37º C.

Mehrez said that from past research her team knows that cannabinoids also lowers immune system activity, which could be bad for someone who’s trying to fight off an infection or a cold, because we become more prone to viruses when our immune system is lowered or suppressed. “But it can be a good thing for people who have autoimmune illnesses, because their problem is that their immune system is attacking their own body. Cannabinoids are being shown to be useful in autoimmune illnesses because they are immunosuppressants and because they don’t have many known negative side effects. So, it seems to be very promising as a potential treatment so far.”

“I’m hoping that understanding how [cannabinoids] affects timekeeping [could] give us insight on how it affects the immune system,” said Mehrez.

Mehrez said that understanding how cannabinoids affect T cells will bring her closer to understanding how they affect overall immune function in healthy people. She added she hopes this research can be followed up to understand how cannabinoids might play a role in autoimmune illnesses.


Photo by Mackenzie Lad

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