Cannabis could help reduce systemic inflammation

A recent study has shown that a compound found in cannabis could help reduce systemic inflammation and immune activation.

Regardless of its legal status, cannabis is a widely used drug across much of the world. Even though it is widespread, cannabis use is disproportionately high in Americans living with HIV – ranging between 20 and 40 per cent.

Conflicting information exists about the impact of cannabis use on HIV positive individuals: some work associates it with a lower viral load (a measure of virus particles in the blood), some suggests it has no effect, some suggests it has a negative effect, being associated with missing doctor’s appointments and cardiovascular disease.

One investigation showed that rhesus macaque monkeys with Simian Immunodeficiency Virus (SIV – the monkey equivalent of HIV, which crossed species into humans and became HIV) given tetrahydrocannabinol (THC – the principal psychoactive component of cannabis) showed reduced inflammation and viral load.

Interestingly, this finding was true for male rhesus macaques, but couldn’t be replicated in females, suggesting a sex specific mechanism.

A team of 14 researchers spread across seven research institutions in America decided to investigate the inflammatory aspect of cannabis.

The team hypothesised that regular cannabis use would be associated with reduced inflammatory cells, and reduced markers of immune activation.

The researchers used samples from 198 HIV positive volunteers from the pre-existing SCOPE study, an ongoing study of both HIV positive and non-HIV positive volunteers based in the University of California, San Francisco, who used cannabis at varying rates and investigated immune cell frequency and activation.

The results demonstrated heavy cannabis use is associated with reduced immune cell frequency and activation.

More specifically, the team found that heavy cannabis users had a reduced frequency of T cells (a white blood cell that plays a central role in immunity) and antigen presenting cells (an immune cell that holds foreign substances in place and presents it for immune cells to recognise) compared to non-cannabis users.

The team also found that the results were the same for male and female humans, even though it doesn’t seem to be true for both male and female rhesus macaques.

One major strength of the work was how the researchers grouped volunteers into cannabis using rate groups – whereas previous studies have done this by self-reporting, the team instead did this by using mass spectrometry (a technique that detects chemicals in a sample based on their mass) to identify THC and its metabolised forms. As a result, the team could, numerically and very directly, show the relationship between cannabis use and immune cell activation.

However, one caveat is that this study was done in HIV positive individuals, so we can’t yet say for sure whether the same is true in non-HIV postive individuals.

But, with this initial finding, and with the high rate of cannabis use in society, it can’t be long before a group attempts to replicate the study in those not infected with HIV.

If and when that study is carried out, The Student will be there to update you!

Image credit: thoughtcatalog via unsplash

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