Ultrastructural analysis of nasopharyngeal epithelial cells from patients with SARS-CoV-2 infection

  1. Karina Lidianne Alcântara Saraiva
  2. Luydson Richardson Silva Vasconcelos
  3. Matheus Filgueira Bezerra
  4. Rodrigo Moraes Loyo Arcoverde
  5. Sinval Pinto Brandão-Filho
  6. Constância Flávia Junqueira Ayres
  7. Regina Célia Bressan Queiroz de Figueiredo
  8. Antonio Pereira-Neves

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Abstract

The nasal epithelium is an initial site for SARS-CoV-2 infection, responsible for the ongoing COVID-19 pandemic. However, the pathogenicity and morphological impact of SARS-CoV-2 on the nasopharynx cells from symptomatic patients with different viral loads remain poorly understood. Here, we investigated the ultrastructure of nasal cells obtained from individuals at distinct disease days and with high and low SARS-CoV-2 loads. Squamous and ciliated cells were the main cells observed in SARS-CoV-2 negative samples. We identified virus-like particles (VLPs) and replication organelles (RO)-like structures in the squamous cells from high viral load samples after 3- and 4-days of symptoms. Ultrastructural changes were found in those cells, such as the loss of microvilli and primary cilium, the increase of multivesicular bodies and autophagosomes, and signs of cell death. No ciliated cells were found in those samples. Squamous cells from low viral load sample after 5 days of symptoms showed few microvilli and no primary cilium. VLPs and RO-like structures were found in the ciliated cells only. No ultrastructural alterations were seen in the cells from low viral load individuals after 10- and 14-days of symptoms. Our results shed light on the ultrastructural effects of SARS-CoV-2 infection on the human nasopharyngeal cells.

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  1. ScreenIT

    SciScore for 10.1101/2021.07.08.451607: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    EthicsConsent: They signed consent and filled out a form including demographic and clinical information.
    IRB: This work was approved by the Aggeu Magalhaes Institute Ethical Committee – CAAE 32333120.4.0000.5190.
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.

    Table 2: Resources

    No key resources detected.

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    One of the limitations in our work is the lack or unavailability of infected individuals with (a) high SARS-CoV-2 loads after more than 4 days of symptoms, and (b) low viral loads with days of symptoms lower than 5. Nevertheless, the results reported here should bring new insights into the impact of SARS-CoV-2 infection on the upper airway epithelial cells and have implications for the understanding of viral transmission and pathogenesis, especially during the first week of symptoms, when the virus shedding is very high57.

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    Results from scite Reference Check: We found no unreliable references.

    About SciScore

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  2. Version published to 10.1101/2021.07.08.451607v1 on bioRxiv