New model of human nose teaches us about viruses

By Gwyn Wright via SWNS

A model of the human nose which captures how viruses such as COVID-19 travel through it has been developed by scientists.

The lab model tracks how coronavirus and respiratory syncytial virus, which tends to cause a common cold in children, travel up our nostrils in the early stages of an infection.

It allows scientists to compare and contrast the pathogens and could offer the clue to vital new therapies for coronavirus and other bugs.

The model, called a human nose organoid system, also found palivizumab, a drug that treats respiratory syndical virus in children, was effective against it.

Respiratory infections such as coronavirus begin in the nose when we breathe in the bug.

For the study, researchers from Baylor College of Medicine in Texas developed a human nose organoid, a lab representation of the cells on the inside of the nose when a respiratory infection first enters it.

They have developed noise organoids from both adults and children.

The cells which exist inside our noses were exposed to air on the top side and our blood circulatory system below it.

To test how each virus behaved, the team placed both the coronavirus and respiratory syncytial virus on the air side and observed how the nose model responded to them.

Its response to each virus was strikingly different.

The coronavirus caused damage to the epithelium in the nose but did not cause much mucus secretion.

Strikingly, an antiviral first response called the interferon response did not take place.

In contrast, exposure to respiratory syncytial virus activated the interferon response and caused mucus to secrete.

The team also found palivizumab was effective at stopping infection with respiratory syncytial virus.

The model could soon be used to work out what makes one person more susceptible to a respiratory virus than another.

It could also be used to examine other respiratory viruses and disease-causing microbes in future, the researchers added.

Corresponding author Dr. Pedro Piedra said: “In the case of respiratory viruses, such as SARS-CoV-2 and RSV, the infection begins in the nose when one breathes in the virus.

“The human nose organoids we have developed provide access to the inside of the human nose, enabling us to study the early events of the infection in the lab, something we had not had before.

“We have successfully developed human nose organoids from both adults and infants.”

“In this study, for the first time, the team described a non-invasive, reproducible and reliable approach to establish human nose organoids that allow for long-term studies.

“Previous models were produced using invasive lung or nose biopsy or broncho alveolar lavage.

“The ease in obtaining the nasal swab samples facilitates our non-invasive approach in the general adult population as well as the vulnerable paediatric population.

“Another advantage of using this novel human nose organoid system is that it can reveal how a person’s initial control of the infection occurs and provide insights into what would make a person more susceptible to a virus than another.

“This system also can be used to study other respiratory viruses and potentially other disease-causing microbes.”

Study co-author Dr Vasanthi Avadhanula said: “We observed divergent responses to SARS-CoV-2 and RSV infection.

“SARS-CoV-2 induces severe damage to the epithelium, no interferon response (an antiviral first defence response), and minimal mucus secretion.

“In striking contrast, RSV induces abundant mucus secretion and a profound interferon response."

Dr Avadhanula added: “In our model, palivizumab effectively prevented RSV infection in a concentration-dependent manner.”

The findings were published in the journal mBio.