THC in cannabis may potentially fight a deadly lung infection that is a common symptom of COVID-19.
Could THC improve the survival rate of COVID-19 patients suffering from the often deadly lung infection known as Acute Respiratory Distress Syndrome and Toxicity (ARDS)? That’s one theory from a new study from a team at the University of South Carolina and the University of Nebraska, Omaha.1)Mohammed, A., Alghetaa, H., Sultan, M., Singh, N. P., Nagarkatti, P., & Nagarkatti, M. (2020). Administration of Δ9-Tetrahydrocannabinol (THC) Post-Staphylococcal Enterotoxin B Exposure Protects Mice From Acute Respiratory Distress Syndrome and Toxicity. Frontiers in Pharmacology, 11, 893. https://doi.org/10.3389/fphar.2020.00893
THC’s anti-inflammatory superpowers demonstrate a unique ability to reduce the severity of ARDS symptoms — at least among lab mice. The researchers behind this new study are pushing to make the connection between THC and ARDS, for the possibility it may evolve into a new treatment for COVID-related ARDS.
Although this study is just based on lab mice and in the very early stages, its results are nevertheless fascinating. With COVID-19 infections continuing to speed up, shouldn’t we pursue all possible avenues?
What is ARDS?
Acute Respiratory Distress Syndrome (ARDS) is a deadly lung infection triggered by an acute systemic inflammatory response in the respiratory system. This response may come from an infection, lung disease, or any other number of conditions. As one research paper explained, ARDS comes from “insults on the lungs.”2)Li, X., Ma, X. Acute respiratory failure in COVID-19: is it “typical” ARDS?. Crit Care 24, 198 (2020). https://doi.org/10.1186/s13054-020-02911-9
ARDS causes severe damage to the specialized cells which line the lungs, called alveoli. When functioning properly, these cells are responsible for rapid gaseous exchange, fundamentally transforming a breath of air into a usable format within the body.
Eventually, these tiny, yet utterly important alveoli fill with fluid, preventing big deep breaths, and limiting oxygen intake. Most people who develop ARDS following injury (or insult) to the lungs die. Few survivors completely recover, and many live with lifelong damage to their respiratory tract.
What Does ARDS Have to Do With COVID-19?
COVID-19 is a potentially deadly lung disease. In severe cases, many patients suffer immense damage to their lungs, which eventually can transform into ARDS. While not all respiratory failures related to COVID-19 are ARDS, there are enough to warrant study.
In Critical Care, Chinese researchers published a paper examining the relationship between COVID-19 and ARDS. In their assessment, many features of COVID-19 related ARDS were identical to other instances, but not all. COVID-19 related cases had a longer period of onset, and triggered less damage to other organs than traditional ARDS, among a few other differences. These differences may be clinically insignificant when it comes to treatment options for COVID-19 cases. On the flip side, they may make traditional interventions more challenging (like the High-flow nasal cannula (HFNC) machine now an infamous reminder to the pandemic). We just don’t know yet.
These differences are also significant for assessments of this new study on THC to treat ARDS. The researchers in this study relied on a different form of ARDS, which may have implications for their findings in relation to COVID-19.
A New Discovery: THC Protects Against Inflammation in ARDS
The authors behind the 2020 publication in Frontiers in Pharmacology investigated THC for the treatment of ARDS in mice. Although they likely started their research before the COVID-19 pandemic began, this fortuitously timed paper is now critical. Could THC be the answer to COVID-19 related ARDS?
The team infected laboratory mice with Staphylococcal enterotoxin B (SEB) to stimulate a “cytokine storm” and severe lung injury. For the layperson, a cytokine storm is, “A severe immune reaction in which the body releases too many cytokines into the blood too quickly. Cytokines play an important role in normal immune responses, but having a large amount of them released in the body all at once can be harmful,” as detailed by the National Cancer Institute. A cytokine storm can happen following infection, autoimmune reaction, or other illnesses, like COVID-19.
These symptoms, the storm, and the lung injury triggered the onset of ARDS in the lab mice. Following the onset, researchers then gave one group of mice with three doses of THC. The results for these THC-dosed mice are nothing short of incredible.
The scientists report that 100 percent of mice infected with SEB died within seventy-two to 102 hours after exposure. But what about the mice who received treatment with THC? One hundred percent survived. As the authors detailed, much of the ARDS-related damages recorded to lung tissue, and respiratory function from SEB infection were reversed with THC.
Too Soon to Treat COVID-19 Patients With THC
This Frontiers in Pharmacology study is exciting news, both for the global rush to find a suitable treatment for COVID-19 and medical cannabis advocates. But, the validity of THC for a deadly lung disease is still only a strong hypothesis at best.
There need to be new rounds of animal studies, seeking to answer some of the questions brought up in this initial trial. Even the authors note, “clearly additional studies are needed to investigate if the mechanisms involved are similar and whether cannabinoids can be used to treat COVID-19 related ARDS.”
Given the pace of COVID-19 related research, the next steps are likely to occur in rapid succession. It may only be months before the next round completes.
References [ + ]
|1.||↑||Mohammed, A., Alghetaa, H., Sultan, M., Singh, N. P., Nagarkatti, P., & Nagarkatti, M. (2020). Administration of Δ9-Tetrahydrocannabinol (THC) Post-Staphylococcal Enterotoxin B Exposure Protects Mice From Acute Respiratory Distress Syndrome and Toxicity. Frontiers in Pharmacology, 11, 893. https://doi.org/10.3389/fphar.2020.00893|
|2.||↑||Li, X., Ma, X. Acute respiratory failure in COVID-19: is it “typical” ARDS?. Crit Care 24, 198 (2020). https://doi.org/10.1186/s13054-020-02911-9|