A nasal spray against COVID-19

One of the main accesses of the SARS-CoV-2 viral particles to the human body is the nasopharyngeal route. For this reason, being able to pharmacologically block this access, especially in populations that are highly exposed to infection such as health staff, could help to reduce the number of cases of COVID-19.

Carrageenans are polysaccharides (union of many monosaccharides or sugars) produced by some red algae that were discovered six hundred years ago in Carraghen, Ireland. Since then, they have been used as thickeners and food stabilizers. Currently, it is used in the food, pharmaceutical and cosmetic industries. 

More than six decades ago, the antiviral properties of carrageenan began to be successfully tested. thus , different studies, in vitro and in animal models, scientists tested its ability to inhibit different enveloped viruses, such as influenza B virus, herpes types 1 and 2 viruses, human immunodeficiency virus, human papilloma, influenza A H1N1, dengue, rhinovirus, hepatitis A, enterovirus and some coronaviruses. 

The antiviral action of carrageenan would function as an electrical barrier that, due to its negative charge, would bind to viral particles, whose envelope contain positively charged proteins. Thus preventing the virus from binding to one of the cell surfaces and blocking its entrance to them. The Carrageenan can also “catch” viral particles released by the cell that have already been infected. 

“This allows us to think that carrageean, applied through nasal spray, can have two different objectives in relation to SARS-CoV-2. On the one hand, stopping the infection via the nasal route in healthy individuals, by shielding the cells that form the epithelium of the nasopharyngeal mucosa. On the other hand, in the case of newly diagnosed infected patients, it can prevent the viral particles released by the dying cells from colonizing new cells, such as the olfactory epithelium, and that allows the pathogen to spread to new pathways, to end up reaching the central nervous system; or to infer more cells of the respiratory epithelium, on the way to the lower respiratory system,” says Osvaldo Uchitel, scientific director of the project and CONICET senior researcher at the ‘Institute of Physiology, Molecular Biology and Neurosciences’ (IFIBYNE, CONICET-UBA), and its first director. 

“If we manage to prevent the virus from reaching the brain or the bronchi and lungs, then the respiratory system would not be compromised, and we could help reduce the number of patients with COVID-19 in serius, or even moderate, condition,” stresses Diana Jerusalinsky, one of the members of the project and CONICET principal researcher at the ‘Institute for Cellular Biology and Neurosciences “Profesor Eduardo de Robertis” (IBCN; CONICET-UBA).’

A frequent symptom of COVID-19 is anosmia or loss of smell. For the researchers, this would occur due to the virus colonization of olfactory epithelial cells, from where it can travel directly to the central nervous system to attack the respiratory center and affect neurons there directly or indirectly through inflammatory processes. For neuroscience specialists Uchitel and Jerusalinsky, preventing this from happening by means of an early treatment is key to preventing SARS-CoV-2 infections from compromising the functioning of the respiratory system. 

“The idea is to undertake two clinical trials. One that will involve the participation of health personnel of from AMBA hospitals, and that will allow us to know to what extent the spray can help present SARS-CoV-2  in people with high exposure to the virus (there will be two populations: one that will be treated with carrangeenan and another, control, who will receive a spray without carrageenan as placebo). The other trial will be conducted with newly diagnosed COVID-19 patients (no longer than 48 hours) with mild symptoms, and will aim to see if the carrageenan applied through nasal spray can help prevent viral particles from reaching the central nervous system,” explains Uchitel. 

Both the results of the experiments undertaken with animal models and in vitro cell lines (which are recorded in the literature), as well as the clinical trials that verified the efficiency of the nasal spray to treat common colds (which involve, in some cases, viruses from the coronavirus family), allow the researchers to be optimistic. 

The other two researchers participating in this study, Juan Manuel Figueroa, clinical director of the project and head of the Child Pneumonology Section of the ‘José San Martín Clinic Hospital,’ and Lorena Itatí Ibáñez,  CONICET researcher at the ‘Institute of Science and Technology César Milstein’ (ICT Milstein, CONICET-Fundación Pablo Cassará), presented in 2015, on the 7th Argentine Congress of Pediatric Pneumonology, a study that showed that carrageenan inhibits viral replication in cultures of a human respiratory epithelial cell line infected with the H1N1 influenza virus. 

“Another significant aspect of this initiative is that in case the results of the clinical trials are what we expect -that is, they show the ability of the spray to decrease cases with COVID-19 among health personnel, to prevent the virus from compromising the respiratory system in patients with a short time of infection, preventing the case from getting worse-, it would be feasible to produce the drug massively and economically. It is worth mentioning that carrageenan is also used in other pharmacological products (in addition to food and cosmetics), and that it is proven that it does not produce adverse effects,” concludes Jerusalinsky.