THC in marijuana could unclog Alzheimer’s brain plaque

JULY 3, 2016 BY MELISSA TAYLOR

A new study suggests that the key agent in marijuana — THC, or tetrahydrocannabinol — just might have an effect in clearing up brain plaque, which is one of Alzheimer’s disease’s key features and one of the key reasons why patients suffer the symptoms they do.

The study, which was published in the journal Aging and Mechanisms of Disease, suggests that THC and other compounds found in marijuana were able to trigger the removal of beta-amyloid protein, which makes up the plaque found in the brain of individuals suffering from Alzheimer’s. Beta-amyloid plaque is a key feature of the disease, and studies have shown that it scrambles communication between brain neurons, thus causing memory problems and other classical symptoms of Alzheimer’s.

Although preventing the buildup of plaque might seem like a no-brainer when it comes to fighting Alzheimer’s disease, the lack of clarity in the role of beta-amyloid in the disease’s progress has made it hard to come up with such a solution. That’s what pushed the researchers to modify nerve cells in order to stimulate protein production.

Based on their findings, heightened production of beta-amyloid did make pro-inflammatory proteins in the nerve cells more expressive, which subsequently resulted in inflammation and nerve cell death.

“Inflammation within the brain is a major component of the damage associated with Alzheimer’s disease, but it has always been assumed that this response was coming from immune-like cells in the brain, not the nerve cells themselves,” said Salk Institute for Biological Studies researcher Antonio Currais, first author of the study.

As the brain’s nerve cells contain receptors which are activated by endocannabinoids, a kind of lipid molecule, the researchers thought of the possibility that marijuana, thanks to its THC content, might prevent the death of nerve cells. They applied THC to the nerve cells which had high beta-amyloid production, and that resulted in reduced beta-amyloid levels, making pro-inflammatory proteins less expressive and preventing the nerve cells from dying.

Although more studies and trials would be needed to prove THC can indeed shield nerve cells from death, the researchers are confident that their findings might inspire the discovery of new treatments for Alzheimer’s, now that the role of beta-amyloid in the development of the disease has become clearer.

“Although other studies have offered evidence that cannabinoids might be neuroprotective against the symptoms of Alzheimer’s, we believe our study is the first to demonstrate that cannabinoids affect both inflammation and amyloid beta accumulation in nerve cells,” said senior author David Schubert, also from the Salk Institute.