Researchers at Johns Hopkins University School of Medicine in Baltimore, Maryland want to know more about one of the strangest side effects of the coronavirus: loss of smell.
Professor Andrew Lane, director of the division of rhinology and skull base surgery, and Dr. Mengfei Chen, a research associate, recently conducted a study to explore this unlikely phenomenon.
The research study, which was published in the European Respiratory Journal in late August, suggests that “this area of the nose could be where the coronavirus is gaining entry to the body,” according to Chen.
Why Does COVID-19 Cause Loss of Smell?
As part of their study, Lane and Chen removed tissue from patients’ noses during surgery. They used fluorescent dyes on the tissue samples to detect and visualize the presence of ACE-2 in the nose cells.
The ACE-2 enzyme has become notorious since the coronavirus pandemic began. It’s the enzyme believed to be the “gateway” that allows COVID-19 to latch onto cells, enter the body, and cause infection.
Through their research, Lane and Chen discovered extremely high levels of ACE-2 in the nose, but only in the “olfactory epithelium” area responsible for detecting smells. Levels of ACE-2 weren’t just “slightly” higher in this area, either; they were between 200 and 700 times higher than other tissue in the nose and trachea, according to Chen.
The olfactory epithelium is quite an easy part of the body for a virus to reach, it’s not buried away deep in our body, and the very high levels of ACE-2 that we found there might explain why it’s so easy to catch COVID-19,” Chen said.
How Can Doctors Use This Information to Treat COVID-19 Patients?
The coronavirus isn’t the only infection to cause temporary loss of smell. Many common respiratory infections, such as coughs and colds, cause this symptom. However, the behavior of ACE-2 enzymes in the olfactory epithelium could help doctors understand why COVID-19 is so infectious and potentially offer more effective treatments.
As explained by Tobias Welte, a professor of pulmonary medicine and director of the Department of Pulmonary and Infectious Diseases at Hannover University School of Medicine, Germany, “It suggests that the part of our nose responsible for smelling could also be the place where the coronavirus gains a foothold in the body. This finding will need to be confirmed, but it offers possible new avenues for treating the infection.”
Identifying the nose as a significant entry point of infection could help doctors prioritize antiviral therapies delivered directly through the nose. It’s an important step in the battle against COVID-19, especially given the unpredictable nature of this pandemic.
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