A cannabinoid science lab led by Prakash Nagarkatti at the University of South Carolina is
also pioneering investigations into the ECS, the gut microbiome, and disease. It may even have found a clue for treating one of the most harmful complications of COVID-19 in some patients.
In a June 2020 study published in Frontiers in Pharmacology, Nagarkatti and colleagues demonstrated that administering THC to mice affected with a form of acute respiratory distress syndrome (ARDS) could stop the condition in its tracks.
A severe consequence of the runaway immune response known as a cytokine storm, ARDS occurs in a small percentage of COVID-19 patients but is often fatal.
THC alters the microbiome in the gut in a way that’s beneficial in suppressing inflammation because bacteria that are favored by THC seem to produce short-chain fatty acids that suppress inflammation.”
“We have a mouse model of ARDS, where we inject Staphylococcal enterotoxin B [a bacterial toxin], and the mice die within four or five days because of cytokine storm and ARDS in the lungs,” Nagarkatti says. “And we found that if you give THC, it cures the mice. They are just running around healthy. That was amazing.”
Nagarkatti doesn’t know exactly how it happens, but he does know it involves the microbiome. “What we found was that THC was changing the gut microbiome, as well as the microbiome in the lungs, and there were similar changes in the gut as well as in the lungs, and then on top of that, when we transplanted the fecal material from the cannabinoid-injected mice into the normal mice, even they became resistant to the ARDS or cytokine storm.”
Though this was demonstrated in mice and is therefore not directly transferable to humans – or COVID-19, for that matter – this is perhaps the first evidence that cannabinoids’ alteration of the gut microbiome can play a role in suppressing the systemic inflammation seen in a cytokine storm, Nagarkatti says.
Interestingly, in one of its first papers on the ECS and the microbiome back in 2017, Nagarkatti’s lab also demonstrated that treatment with a combination of THC and CBD altered the gut microbiome in mice in a way that reduced inflammation, in this case with beneficial implications for autoimmune disease.
“Suppressing inflammation in the colon as well as systemically is very critical for preventing any type of disease, because right now inflammation is considered to be the underlying cause of everything, not only autoimmune disease but cardiovascular and neurodegenerative diseases, PTSD, Alzheimer’s, obesity, cancers, COVID-19,” Nagarkatti says. “You name it and there is inflammation.”
While the molecular mechanisms still need to be worked out, the ECS plays an important role in modulating inflammation through gut microbiota.
Nagarkatti reports: “THC alters the microbiome in the gut in a way that seems to be beneficial in suppressing inflammation because bacteria that are favored by THC or cannabinoids seem to produce short-chain fatty acids that suppress inflammation.”