It seems that there’s a laundry list of illnesses these days that can be traced back to the state of our gut, and scientists are now adding COVID-19 to it. Researchers from Flinders University in Australia have shown a molecular link between COVID-19 and serotonin cells in the gut, which could be key to understanding infection and severity of the virus.
“Our study endeavoured to understand whether the gut could be a site of disease transmission and what genes might be associated with the virus entering the cells lining the gut wall,” says study senior author Damien Keating, Deputy Director of the Flinders Health and Medical Research Institute, in a statement.
To conduct their work, researchers began by examining different cell types within the gut lining, analyzing whole genome sequences from thousands of cells in the intestine. They discovered that certain cells in the gut capable of synthesizing and releasing serotonin also have strong expression of SARS-CoV-2 receptors. These cell types were the only ones capable of expressing all genes related to the virus.
“Many genes linked to COVID-19 were found expressed in the different cell types lining the gut wall, but only serotonin cells expressed all three receptors for the virus,” explains Professor Keating.
Thus, these genes are clearly very strong. The fact that they can express all three receptors means that they are also able to triple the infection rate, according to Keating.
Despite being roughly three years into the pandemic, the leading determinant for developing severe COVID-19 and where exact sites of infection are remain not well-understood. However, the authors are proud of the work they’ve done and how they’ve demonstrated that the gut indeed plays a role in the virus. They express that their findings support the notion that COVID-19 is able to jack up serotonin levels by how it acts on specialized gut cells, which can consequently lead to more severe disease outcomes.
Study authors even began to think about how their results may be transferrable for mental health research and related therapeutic options. They believe that it further solidifies the importance of prescribing antidepressant treatment options that are able to inhibit serotonin activity around the body, such as SSRIs. Since COVID-19 won’t entirely go away, they conclude that it’s crucial to keep building on this research and to find ample treatment that works during severe disease to support vaccination prevention efforts.
This study is published in the journal Gut.