Recent Developments in Medicinal Cannabis Research

March 2000

Two papers published this month add to the growing body of scientific evidence as to the effectiveness of cannabis or cannabinoids in two quite different medical conditions.

Cannabis 'May trigger cancer cell suicide'

Scientists at Complutense University in Madrid, led by Dr Manuel Guzman, found THC infusions to kill cancerous 'glioma' cells in the brains of mice. Glioma is a rare form of malignant brain cancer, and affects around 1800 people a year in the UK. Gliomas are extremely difficult to treat. Even after a course of surgery, radiation and chemotherapy, the median survival rate is less than a year.

Researchers induced tumours in the brains of 45 rats. A third were given THC, the main active chemical in cannabis, a third were given a synthetic cannabinoid, while the rest were used as controls.

Within 18 days the untreated rats died but, when THC and the man-made cannabinoid were injected directly in the tumours over seven days, they had a dramatic effect. The chemicals destroyed the tumours in a third of the mice and prolonged the life of another third by up to six weeks. Guzman reported "These results may provide the basis for a new therapeutic approach for the treatment of malignant gliomas"

The team believe that cannabinoids trigger the build-up of a chemical messenger, ceramide, which in turn leads to programmed cell death in the tumour in a selective way, only triggering cell death in cancerous brain cells - stimulating the cancer cells to commit suicide in a natural process called apoptosis. Future studies will try to discover why cannabinoids appear to have no effect on healthy brains and whether they can be used on people.

Pharmacologist Daniele Piomelli, who wrote a commentary for the Spanish research, published in the March 2000 issue of 'Nature Medicine', commented to the UPI press agency:

"This is the first convincing study to show that a marijuana-based drug treatment may combat cancer. If the drug works as well in humans, then this will be a paper of great importance."

THC causes instant symptom relief in mice with MS

Meanwhile, a report in Nature from a team of scientists led by David Baker of the Institute of Neurology in London have provided further evidence of the effectiveness of cannabinoids in treating Multiple Sclerosis. Investigating the effects of tremor in mice, the team found THC and similar compounds (CB1 receptor agonists) to abolish tremor virtually immediately, an effect which was blocked or reversed by CB1 receptor antagonists (blockers). Mice suffering from chronic allergic encephalomyelitis (CREAE) - an animal model for MS - were injected with THC as well as three synthetic cannabinoids, including methanandamide which is similar to the main cannabinoid produced naturally in the body. All had a significant ability to reduce both tremor and spasticity. The powerful CB1 agonist WIN55212 proved the most effective.

The paper concluded that a natural control mechanism was being influenced as well as the effect of the compounds,suggesting the purpose of the receptors - and the natural cannabinoids which bind to them - is to maintain motor control.

Baker told the Times "One of their functions is to provide a protective filter mechanism to limit excess excitation of the nerves. In a normal animal or human being it provides fine control over motor function."

Quoted in the Guardian, Baker stated "Although not a cure, our research suggests that cannabinoids can play a crucial role in controlling some of the neuromuscular problems seen with MS."

Reuters quoted Lorna Layward of the MS society, and co-author of the report: "This is the first time it has been shown objectively and scientifically that cannabis derivatives can control some of the symptoms of multiple sclerosis"

Nature 2000;404:84-87

Marijuana Skin Patch developed in USA

Dr. Audra Stinchcomb, from the Albany College of Pharmacy in New York, who has spent the past two years developing a slow-release skin patch, christened the "pot patch" or "doobie derm" by colleagues, was in January awarded was a $361,000 grant from the American Cancer Society. The project was screened by three panels of doctors, scientists and staff members as part of the application process, and has also been approved by the US Drug Enforcement Administration, which regulates experiments with illegal drugs. The patch would use synthetic cannabinoids created in a laboratory and is years away from being tested on people.

Dr. Eric Voth, chairman of the US based International Drug Strategy Institute, a pro drug-war organization which reviews drug policies, said the patch could pass along the therapeutic effects of marijuana without making the drug available.

``It's no more a marijuana patch than a nicotine patch is a tobacco patch,'' Voth said. ``I'm all for trying to find pure, reliable medicine, but I do not support the idea of smoking weed for medicinal purposes.''

Source: San Francisco Chronicle, Thu, 03 Feb 2000