Cannabis treatment for endometriosis

Mice with the disease respond to THC, so might the same be true of humans?
05 March 2020

Interview with 

Rafael Maldonado, Universitat Pompeu Fabra, Barcelona


A mouse model of endometriosis, characterised by cyst formation


One in ten women has the condition endometriosis; the consequences can include disabling menstrual pain, and infertility. The disease occurs, we think, when the lining of the uterus, instead of leaving the body as menstrual blood, instead passes in the reverse direction, upwards along the fallopian tubes and into the abdominal cavity, where it implants in various places and produces cysts that bleed painfully and provoke inflammation and adhesions. Now, Rafael Maldonado, from the Universitat Pompeu Fabra, Barcelona, has successfully recreated the condition in mice, and gone on to show that THC, one of the main psychoactive ingredients in cannabis, can reverse the activity of the disease, suggesting that this might be a fruitful avenue to pursue in human patients…

Rafael - I'm Rafael Maldonado, from the Universitat Pompeu Fabra, Barcelona. I'm director of the neuropharmacology research group. What we do is we extract some uterus tissue from normal mouth and we just implant this uterus tissue in the abdominal cavity. And of course we have a control animal where we just implant fat in the same places. Only the animal where we have implanted this uterus tissue is the one that express pain, but also expresses other manifestation similar to women that has endometriosis and emotional alteration and cognitive alteration.

Chris - So women who have endometriosis don't just get pain once a month when they're menstruating. They also get these other consequences you're describing, including decision making and cognitive impairments?

Rafael - That's correct.

Chris - So you've got this animal model then; it develops many of the symptoms of endometriosis. It means that you've now got an opportunity to try various therapies.

Rafael - Yes.

Chris - What did you decide to test?

Rafael - Well, we focused on the endocannabinoid system. This system is involved in the transmission and integration of pain; it's involved in day emotional control; it's involved in the cognitive control. So for these and other reasons, we have arguments to believe that we are going to be able to modify the manifestations of endometriosis.

Chris - What did you do then? You give the mice who've got either the control tissue or the mice that have got the uterine tissue, so they are endometriotic mice. You give them some THC - tetrahydrocannabinol - and you then ask what does this do to their symptomatology?

Rafael - Yeah, we give tetrahydrocannabinol at a dose that is equivalent to a medium dose in humans. We administered this cannabis chronically in the animal. And then the animal feels less pain. Then we evaluate the emotional component and we had decreased the cognitive impairment and we had decreased the size of the cyst at the peripheral level. So, we suppose that this effect is the combination of as central and a peripheral response produced by THC.

Chris - And when you look inside the animals, can you see any differences in the way the tissue is behaving when you treat the animals with THC?

Rafael - Yeah, we do. We observe a decrease in the size of the cyst. We observe a decrease in the size of the cyst that generates this disease that is called endometriosis.

Chris - Do you think it will be possible to dissect away some of the psychoactive effects of THC and still achieve these benefits so that people would potentially get the benefits for endometriosis, but none of the central consequences?

Rafael - Yeah. These are, these are the studies that we are doing right now trying to obtain just the beneficial effects avoiding the central psychoactive effects of THC.


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