RESEARCH CORNER

COLLECTED BY MATT JACKSON, PHD RESEARCH CORNER

When Combined, THC and CBD Reduced the Progression of Multiple Sclerosis (MS) in an Experimental Mouse Model Research from the University of South Carolina School of Medicine, published in the Frontiers in Immunology journal in August 2019

STUDY DESIGN ● Researchers injected mice with compounds that caused brain inflammation and symptoms of MS, which began progressing about 8–10 days later. At that point, mice were treated with combined THC and CBD (THC+CBD) over the next week, each at 10 mg per kg body weight. ● Researchers rated MS progression from zero to five: zero (no symptoms), one (limp tail), two (weak hind legs), three (paralyzed hind legs), four (partially paralyzed front legs), then five (complete paralysis). ● Mice are typically euthanized if they maintain level four or reach level five, after which researchers examined brain tissue to understand how treatments affected neurological inflammation.

BOTH THC+CBD WERE REQUIRED TO PREVENT MS PROGRESSION, NOT JUST ONE OR THE OTHER ● THC+CBD treatments prevented about 80% of the mice from developing any symptoms of MS (level 0). This was a drastic improvement compared with treatments using only THC or CBD (but not both) and no treatment at all, where MS progressed the same in all cases, with 60% developing level 3–5 symptoms. ● The researchers repeated these experiments with mice specifically bred to genetically lack the cannabinoid receptors CB1 and CB2, and the THC+CBD treatments were no longer effective. This and other data showed THC+CBD activated the endocannabinoid system to prevent MS progression.

WHAT WAS THE BIOLOGICAL BASIS FOR SUCH ASTOUNDING RESULTS? ● MS is an autoimmune disorder where immune cells (specifically T-cells) cross into the brain, cause inflammation, and damage the brain tissue to cause symptoms of MS. ● When researchers examined tissue after THC+CBD treatments, they found fewer molecules that trigger inflammation, fewer T-cells infiltrating the brain, and less brain damage. ● The researchers connected the effectiveness of THC+CBD treatments with changes in genetic molecules called micro-RNAs, which prevented inflammation by causing T-cells to enter a process of controlled cell death.

IS THERE ANY CONNECTION TO CLINICAL TRIALS IN HUMANS? ● This study did not involve humans, but the researchers pointed to Sativex, a pharmaceutical cannabis extract that also has an equal ratio of THC+CBD and is approved in over 25 countries outside the U.S. for treating muscle spasticity in MS.

BOTH THC+CBD WERE REQUIRED TO PREVENT MS PROGRESSION, NOT JUST ONE OR THE OTHER