Anthropologists have observed that the members of a tribe in Africa’s Congo Basin who regularly smoke marijuana have far fewer intestinal parasites than tribe members who don’t use cannabis.
It was a curious finding that suggested an interesting, if unintentional, example of medical marijuana.Now a University of Toledo researcher believes he knows why — and potentially how to harness that knowledge to develop new treatments that could rid humans and livestock of roundworms without relying on traditional anthelmintic drugs.
“Studying how nematodes reacted to cannabis gave us a window into a potential new mode of action,” said Dr. Richard Komuniecki, Distinguished University Professor Emeritus of Biological Sciences at The University of Toledo. “Cannabis really limits locomotion in these animals, and they exhibit a dazed and confused behavior. They can’t decide whether to move forward or backward, which is a druggable phenotype.”
Most anti-parasitic drugs currently on the market to treat intestinal parasites work by causing paralysis in the worms, allowing the body to expel them. It is possible the limited locomotion Komuniecki’s work has observed could be enough to release the worm from the host.
While additional animal testing is needed to confirm the theory, the early findings from Komuniecki and his graduate student researchers, Wenjin Law and Mitchell Oakes, are significant because of their potential to add a new treatment in an area that hasn’t seen much recent development.
“In contrast to things like bacteria where we can develop antibiotics, these animals are so closely related to humans that usually compounds that kill nematodes also kill humans,” Komuniecki said. “Anthelmintic drug discovery has been very slow for that reason. Also, resistance is beginning to arise in a lot of the compounds on the market today.”
For his initial research, Komuniecki introduced cannabinoids to a non-parasitic nematode, or roundworm, known as Caenorhabditis elegans. The tiny worms, which have long been used in scientific research, stopped feeding and exhibited erratic motor function once they were exposed to the compounds.
After studying the worm’s reaction, UT researchers determined they could produce the same reaction by targeting the worms’ serotonin receptors. Komuniecki has worked with Dr. Paul Erhardt, Distinguished University Professor and director of UT’s Center for Drug Design and Development, to identify compounds that could be used as treatment.
“The cannabis work allowed us to identify these receptors as novel drug targets,” Komuniecki said.
More than 2 billion people worldwide are affected by parasites, while the global agricultural industry loses billions of dollars a year to parasitic infections.
Komuniecki’s work on parasitic worms has been continuously funded by the National Institutes of Health for more than 35 years.