Patients with the COVID-19 disease can display a variety of respiratory symptoms like coughing, sneezing, fever, and shortness of breath. The disease is transmitted via droplets that are expelled when coughing or sneezing. About a third of COVID-19 patients have nausea and diarrhea, and it has been discovered that the virus can be found in stool long after the respiratory symptoms dissipate. This suggests a possible fecal-oral transmission of the virus.
The ACE-2 receptor is how SARS-CoV-2 enters the body’s cells. Both respiratory and gastrointestinal organs have ACE-2 receptors but until now nobody knew if intestinal cells could be infected with the coronavirus.
Scientists from the Hubrecht Institute in Utrecht, Erasmus MC University Medical Center Rotterdam, and Maastricht University in the Netherlands discovered that coronavirus could infect the cells of the human intestine. Using human intestine cell cultures called organoids, the scientists could grow the virus in vitro and they monitored how the intestinal cells responded to the virus. According to Hans Clevers of the Hubrecht Institute, “These organoids contain the cells of the human intestinal lining, making them a compelling model to investigate infection by SARS-CoV-2."
These findings could explain how so many COVID-19 patients show gastrointestinal symptoms. The study results were published in the May 1st edition of the journal, Science.
The scientists studied the response of the intestinal cells to the virus with RNA sequencing, a method to study which genes are active. What they discovered is that “interferon-stimulated” genes, which are known to help fight viral infection, are activated. The scientists will perform further studies that focus on these genes and their ability to use this information to develop new COVID-19 therapies.
Says Bart Haagmans from Erasmus MC, "The observations made in this study provide definite proof that SARS-CoV-2 can multiply in cells of the gastrointestinal tract. However, we do not yet know whether SARS-CoV-2, present in the intestines of COVID-19 patients, plays a significant role in transmission. Our findings indicate that we should look into this possibility more closely."