Researchers at North Carolina State University and the University of North Carolina-Chapel Hill have performed successful studies on a nasal spray that can potentially help treat COVID-19.
The researchers developed cells that are very similar to a type of cell found in the lungs. Using a nasal spray device, the user can inhale those mimicking cells. When the virus that causes COVID-19, known as SARS-CoV-2, enters the body, it is overwhelmed by the fake cells and cannot find the real lung cells.
When the virus binds to the surfaces of the fake cells, it is not able to infect them, replicate itself and then go infect other cells. The body’s immune system is able to clear the virus as it sits idly on the fake cells.
The nasal spray used to get the fake cells into the body is made by first putting the fake cells in saline. A nebulizer turns the liquid — the saline and the fake cells — into a mist that the user inhales.
To test the therapy, the researchers inserted a virus that closely resembles the SARS-CoV-2 virus into mice and monkeys and had them inhale the nasal spray. They found that the therapy quickly cleared the virus from the animals’ bodies. The fake cells remained in the mice’s lungs for 72 hours, and the researchers also noted reduced inflammation and fibrosis — tissue growth in response to damage — in the monkeys’ lungs.
What are ‘nanodecoys’ and how are they made?
The researchers put several types of cells into a culture where they could multiply and form cell clusters. These clusters of cells are known as lung spheroid cells (LSCs), which were then pushed through a series of filters in a process known as microextrusion.
As the LSCs moved through the filters, they were separated into many small vesicles called nanodecoys. Each nanodecoy is about 200 to 300 nanometers in size. A human hair is about 80,000 to 100,000 nanometers wide.
This method is why the therapy will presumably work with coronavirus variants. The surface of the nanodecoys is the same as the surface of the lung cells from which they are made. As long as the virus can bind to the surface of real lung cells, it can also bind to the fake cells.
“Based on the evolution, whatever the various variants are, no matter how much they change, as long as they enter the lung cells, we can attack them because we’re using the membrane of our own lung cells to bind the virus,” explained Dr. Ke Cheng, Randall B. Terry Jr. Distinguished Professor in Regenerative Medicine at North Carolina State University and a professor in the NC State/UNC-Chapel Hill Joint Department of Biomedical Engineering. Cheng was a coauthor of the study,
Each LSC can filter into about 11,000 nanodecoys. Nanodecoys are not living cells, which is why the virus cannot infect them or replicate when it binds to them. They are safe, as they are less likely to cause tumors or generate a harmful immune response than real cells would be. Because they are so small, it’s also very easy for immune cells to get rid of them when they’re no longer needed. They have been used before to investigate other viruses in animals, such as human immunodeficiency virus, or HIV.
When will this therapy be ready for use in humans?
The researchers now need to figure out how to translate the therapy to be tested in humans and the specific methods the body uses to clear out the nanodecoys.
Cheng told The News & Observer that he is “on the confident side, but wouldn’t say 100% confident” about how the therapy will perform in human trials.
The researchers need approval from the Food and Drug Administration before they’re able to test the therapy in humans. Cheng said this process is likely to take months.
He noted that they are hoping to receive an Emergency Use Authorization from the FDA, “especially for severely ill patients where they’ve tried everything.” EUAs have been used for COVID-19 treatments, such as the antiviral drug remdesivir in 2020, and several vaccines.
“If the remdesivir or monoclonal antibodies aren’t working, particularly in those cases, we would like to apply for emergency use if the clinical trial data is positive,” Cheng said.
Dr. Jason Lobo, a pulmonologist at UNC, was also a coauthor of the study. He did not respond to multiple email requests for an interview.