How marijuana smoking changes bacterial communities in the mouth and affects the brain

Inspiration pops up
when you least expect it.
For Wei Jiang, a professor of microbiology and immunology at the Medical University of South Carolina (MUSC), inspiration came from a smoky cruise through Amsterdam during an international conference in 2018
.

"Everyone smokes marijuana
except me.
" "I was studying the microbiome at the time, so after talking to them, I found that their oral health was affected by smoking, and I wanted to know more about that
.
"

In the years since, Jiang has focused on studying how smoking cannabis changes the oral microbiome, or the community of
bacteria that live in the mouth.
The South Carolina Clinical and Translational Institute provided pilot funding
for Chiang's research.

Now, with a recent $3.
7 million grant from the National Institute on Drug Abuse (NIDA), Jiang and her collaborator, Dr.
Sylvia Fitting of the University of North Carolina at Chapel Hill, will delve into the impact of marijuana-induced changes in the oral microbiota and their impact
on neurological disorders.

"This will be the first study to investigate how cannabis alters the oral microbiome and its effects on the brain," Jiang said
.

Marijuana is the most widely used drug in the United States and has positive psychiatric effects, such as reducing anxiety
.
However, long-term use can lead to impaired
memory, learning, and motor skills.
Smoke also contains harmful compounds produced by combustion, which can affect oral health
.

Changes in oral bacteria have been linked
to cardiovascular disease, premature birth and even Alzheimer's disease.
Unnatural changes in the oral microbiome, so-called dysbiosis, allow harmful bacteria to multiply in the mouth and even enter the bloodstream, damaging other organs, such as the brain
.

Jiang and her collaborators showed in a December 2021 electronic biomedical study that frequent cannabis use alters the oral microbiome
.
They found that levels of A.
meyeri were unusually high in people who regularly smoked marijuana, but not in tobacco or cocaine users
.

"In general, in a healthy oral microbiome, a.
The number of meyeri should be very low," Jiang said
.

Oral A.
Mice at 6 months of Meyeri showed increased inflammation and increased
amyloid in the brain.
These proteins are thought to be linked
to long-term memory loss and Alzheimer's disease.

"After we saw these changes in mice injected with this bacteria, we were very interested in what was happening in
their brains," Chiang said.

The new grant funding will allow the team to explore high levels of A in the oral microbiome of frequent marijuana smokers.
The mechanism
of the link between meyeri and neurological disorders.

"Psychological dependence on drugs can have harmful effects on the nervous system, but we don't know what causes heavy cannabis users to have these effects," Jiang said
.
"We know that oral health can affect your mental health
.
However, we don't know exactly what role the microbiome
plays.
”

Although Jiang's earlier work showed that cannabis' altered oral microbiome played a role in changes in the nervous system, it did not specifically study what components of cannabis caused those changes
.
Cannabis contains psychoactive ingredients (THC) and non-psychoactive ingredients (CBD), which interact
with the brain and nervous system in different ways.

"Now, we want to determine the specific effects of THC and CBD on oral microbiota dysbiosis and mental health," Jiang said
.

Jiang plans to expose mice to different levels of THC and CBD to determine their effects on the oral microbiome.
Effects of
meyeri levels.

"We believe that long-term exposure to THC, rather than CBD, increases A.
MEYERI levels and led to harmful effects on the nervous system of mice," Chiang said
.

In the new study, Jiang will also expand from a mouse model to humans with cannabis use disorder to see how changes in the oral microbiota affect memory
.

Jiang said: "We expected that people who regularly used marijuana had higher levels of memory-related deficits compared to those who did not use cannabis.
Meyeri related
.
”

Professor Jiang's research highlights the importance of oral health and its complex relationship with
other diseases.

"Anyone who regularly uses cannabis should pay special attention to their oral hygiene"
.

With support from NIDA grants, Jiang plans to lay the groundwork for the
development of treatments that target the oral microbiota of frequent cannabis users with neurological disorders.

"If our hypothesis is correct, target a .
Meyeri's therapeutic strategies can reduce brain function irregularities in people who regularly smoke marijuana," Jiang said
.
"In the future, screening certain bacteria for different diseases that affect the brain, such as Alzheimer's disease, may also be useful
.
"