A new study suggests the active ingredient in marijuana delays the rejection of incompatible organs in mice. The results were published in the Journal of Leukocyte Biology.
For the study, researchers transplanted the skin from one group of mice to a group of genetically different mice. The incompatible skin was treated with either a placebo or THC, the active compound in cannabis.
Due to the genetically different nature of the transplants, the mice's immune systems should have recognised the tissue as foreign and rejected it. However, the THC-treated transplants delayed rejection of the skin grafts when compared to the placebo group.
"We are excited to demonstrate for the first time that cannabinoid receptors play an important role in the prolongation of rejection of a foreign graft by suppressing immune response in the recipient," said Mitzi Nagarkatti, co-author of the study from the University of South Carolina School of Medicine, in a statement.
If the same holds true for humans, THC could be used as an anti-rejection therapy – especially for patients whose transplanted organ is not adapting well to its new host.
"This opens up a new area of research that would lead to better approaches to prevent transplant rejection as well as to treat other inflammatory diseases,” added Nagarkatti.
To delve into this connection further, the researchers examined the possible reason for this delayed rejection. It turns out, the active ingredient in marijuana reduced T-cell proliferation and decreased early stage rejection-indicator cytokines.
"More and more research is identifying potential beneficial effects of substances contained in marijuana, but a major challenge has been identifying the molecular pathways involved," said John Wherry, deputy editor of the Journal of Leukocyte Biology, in the statement. "These new studies point to important roles for the cannabinoid receptors as targets that might be exploited using approaches that refine how we think about substances derived from marijuana."
As this study was only performed on mice, more research is needed to determine if the results can be replicated in humans. Transplant patients should only use marijuana with their physician's consent and in accordance to local laws.