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Through The Back Door: Expiratory Accumulation of SARS-Cov-2 in the Olfactory Mucosa as Mechanism for CNS Penetration

Introduction: SARS-CoV-2 is a respiratory virus supposed to enter the organism through aerosol or fomite transmission to the nose, eyes and oropharynx. It is responsible for various clinical symptoms, including hyposmia and other neurological ones. Current literature suggests the olfactory mucosa as...

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Autores principales: Pipolo, Carlotta, Bulfamante, Antonio Mario, Schillaci, Andrea, Banchetti, Jacopo, Castellani, Luca, Saibene, Alberto Maria, Felisati, Giovanni, Quadrio, Maurizio
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Ivyspring International Publisher 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8040411/
https://www.ncbi.nlm.nih.gov/pubmed/33859516
http://dx.doi.org/10.7150/ijms.56324
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author Pipolo, Carlotta
Bulfamante, Antonio Mario
Schillaci, Andrea
Banchetti, Jacopo
Castellani, Luca
Saibene, Alberto Maria
Felisati, Giovanni
Quadrio, Maurizio
author_facet Pipolo, Carlotta
Bulfamante, Antonio Mario
Schillaci, Andrea
Banchetti, Jacopo
Castellani, Luca
Saibene, Alberto Maria
Felisati, Giovanni
Quadrio, Maurizio
author_sort Pipolo, Carlotta
collection PubMed
description Introduction: SARS-CoV-2 is a respiratory virus supposed to enter the organism through aerosol or fomite transmission to the nose, eyes and oropharynx. It is responsible for various clinical symptoms, including hyposmia and other neurological ones. Current literature suggests the olfactory mucosa as a port of entry to the CNS, but how the virus reaches the olfactory groove is still unknown. Because the first neurological symptoms of invasion (hyposmia) do not correspond to first signs of infection, the hypothesis of direct contact through airborne droplets during primary infection and therefore during inspiration is not plausible. The aim of this study is to evaluate if a secondary spread to the olfactory groove in a retrograde manner during expiration could be more probable. Methods: Four three-dimensional virtual models were obtained from actual CT scans and used to simulate expiratory droplets. The volume mesh consists of 25 million of cells, the simulated condition is a steady expiration, driving a flow rate of 270 ml/s, for a duration of 0.6 seconds. The droplet diameter is of 5 µm. Results: The analysis of the simulations shows the virus to have a high probability to be deployed in the rhinopharynx, on the tail of medium and upper turbinates. The possibility for droplets to access the olfactory mucosa during the expiratory phase is lower than other nasal areas, but consistent. Discussion: The data obtained from these simulations demonstrates the virus can be deployed in the olfactory groove during expiration. Even if the total amount in a single act is scarce, it must be considered it is repeated tens of thousands of times a day, and the source of contamination continuously acts on a timescale of several days. The present results also imply CNS penetration of SARS-CoV-2 through olfactory mucosa might be considered a complication and, consequently, prevention strategies should be considered in diseased patients.
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spelling pubmed-80404112021-04-14 Through The Back Door: Expiratory Accumulation of SARS-Cov-2 in the Olfactory Mucosa as Mechanism for CNS Penetration Pipolo, Carlotta Bulfamante, Antonio Mario Schillaci, Andrea Banchetti, Jacopo Castellani, Luca Saibene, Alberto Maria Felisati, Giovanni Quadrio, Maurizio Int J Med Sci Research Paper Introduction: SARS-CoV-2 is a respiratory virus supposed to enter the organism through aerosol or fomite transmission to the nose, eyes and oropharynx. It is responsible for various clinical symptoms, including hyposmia and other neurological ones. Current literature suggests the olfactory mucosa as a port of entry to the CNS, but how the virus reaches the olfactory groove is still unknown. Because the first neurological symptoms of invasion (hyposmia) do not correspond to first signs of infection, the hypothesis of direct contact through airborne droplets during primary infection and therefore during inspiration is not plausible. The aim of this study is to evaluate if a secondary spread to the olfactory groove in a retrograde manner during expiration could be more probable. Methods: Four three-dimensional virtual models were obtained from actual CT scans and used to simulate expiratory droplets. The volume mesh consists of 25 million of cells, the simulated condition is a steady expiration, driving a flow rate of 270 ml/s, for a duration of 0.6 seconds. The droplet diameter is of 5 µm. Results: The analysis of the simulations shows the virus to have a high probability to be deployed in the rhinopharynx, on the tail of medium and upper turbinates. The possibility for droplets to access the olfactory mucosa during the expiratory phase is lower than other nasal areas, but consistent. Discussion: The data obtained from these simulations demonstrates the virus can be deployed in the olfactory groove during expiration. Even if the total amount in a single act is scarce, it must be considered it is repeated tens of thousands of times a day, and the source of contamination continuously acts on a timescale of several days. The present results also imply CNS penetration of SARS-CoV-2 through olfactory mucosa might be considered a complication and, consequently, prevention strategies should be considered in diseased patients. Ivyspring International Publisher 2021-03-15 /pmc/articles/PMC8040411/ /pubmed/33859516 http://dx.doi.org/10.7150/ijms.56324 Text en © The author(s) https://creativecommons.org/licenses/by/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/). See http://ivyspring.com/terms for full terms and conditions.
spellingShingle Research Paper
Pipolo, Carlotta
Bulfamante, Antonio Mario
Schillaci, Andrea
Banchetti, Jacopo
Castellani, Luca
Saibene, Alberto Maria
Felisati, Giovanni
Quadrio, Maurizio
Through The Back Door: Expiratory Accumulation of SARS-Cov-2 in the Olfactory Mucosa as Mechanism for CNS Penetration
title Through The Back Door: Expiratory Accumulation of SARS-Cov-2 in the Olfactory Mucosa as Mechanism for CNS Penetration
title_full Through The Back Door: Expiratory Accumulation of SARS-Cov-2 in the Olfactory Mucosa as Mechanism for CNS Penetration
title_fullStr Through The Back Door: Expiratory Accumulation of SARS-Cov-2 in the Olfactory Mucosa as Mechanism for CNS Penetration
title_full_unstemmed Through The Back Door: Expiratory Accumulation of SARS-Cov-2 in the Olfactory Mucosa as Mechanism for CNS Penetration
title_short Through The Back Door: Expiratory Accumulation of SARS-Cov-2 in the Olfactory Mucosa as Mechanism for CNS Penetration
title_sort through the back door: expiratory accumulation of sars-cov-2 in the olfactory mucosa as mechanism for cns penetration
topic Research Paper
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8040411/
https://www.ncbi.nlm.nih.gov/pubmed/33859516
http://dx.doi.org/10.7150/ijms.56324
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