Although severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections mainly attack the lungs, in many cases they can also damage other organs, such as the colon: Around 60% of patients, in fact, experience digestive tract impacts. Researchers at MedUni Vienna, Austria, have analyzed the manifestations of COVID-19 in the lungs and colon and pinpointed the differences at
a molecular level.

Their findings, published recently in the International Journal of Molecular Sciences, may form the basis for the identification of novel biomarkers and the development of new treatment strategies.

The team led by Diana Mechtcheriakova from MedUni Vienna’s Institute of Pathophysiology and Allergy Research studied the singularities and commonalities in the impact of COVID-19 on the lungs and other organs. Using complex dataset analyses, the researchers recognized that a different molecular mechanism is involved in pulmonary and gastrointestinal (GI) manifestations. While SARS-CoV-2 infections of the lungs elicit classic immune system responses, in the GI tract they elicit responses related to liver and lipid metabolism.

The fact that SARS-CoV-2 infections not only manifest in the lungs but frequently also manifest in other organs, such as the heart, kidneys, skin, or gut, can be attributed to the particular structure of the virus. During the course of COVID-19, up to 60% of patients experience GI symptoms, which may be associated with a longer duration of disease and/or a worse outcome. The results of this study will add to our understanding of the organ- and tissue-specific molecular processes triggered by SARS-CoV-2.

“Our findings can advance the identification of new biomarkers and treatment strategies for COVID-19, taking account of the specific responses in manifestations outside the lung,” said Dr. Mechtcheriakova.

In other research, findings from Flinders University in Adelaide, Australia, demonstrate a molecular link between COVID-19 and serotonin cells in the GI tract. The study, published in the journal Gut, could help provide further clues to what could be driving COVID-19 infection and disease severity and supports previous evidence that selective serotonin reuptake inhibitors could reduce the severity of COVID-19 symptoms.

COVID-19 displays an array of symptoms, which can include GI issues such as diarrhea. Recent research has indicated that these gut symptoms in COVID-19 patients worsen with disease severity, and this is linked to heightened gut-derived serotonin released to cause gut dysfunction, increasing the body’s immune response and potentially worsening outcomes.

“Our study endeavored 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,” said study senior author Damien Keating, deputy director of the Flinders Health and Medical Research Institute and head of the Gut Sensory Systems research group.

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