Anatomical barriers against SARS-CoV-2 neuroinvasion at vulnerable interfaces visualized in deceased COVID-19 patients

Mona Khan; Marnick Clijsters; Sumin Choi; Wout Backaert; Michiel Claerhout; Floor Couvreur; Laure Van Breda; Florence Bourgeois; Kato Speleman; Sam Klein; Johan Van Laethem; Gill Verstappen; Ayse Sumeyra Dereli; Seung-Jun Yoo; Hai Zhou; Thuc Nguyen Dan Do; Dirk Jochmans; Lies Laenen; Yves Debaveye; Paul De Munter; Jan Gunst; Mark Jorissen; Katrien Lagrou; Philippe Meersseman; Johan Neyts; Dietmar Rudolf Thal; Vedat Topsakal; Christophe Vandenbriele; Joost Wauters; Peter Mombaerts; Laura Van Gerven

doi:10.1016/j.neuron.2022.11.007

Anatomical barriers against SARS-CoV-2 neuroinvasion at vulnerable interfaces visualized in deceased COVID-19 patients

Neuron. 2022 Dec 7;110(23):3919-3935.e6. doi: 10.1016/j.neuron.2022.11.007. Epub 2022 Nov 10.

Authors

Mona Khan¹, Marnick Clijsters², Sumin Choi¹, Wout Backaert³, Michiel Claerhout⁴, Floor Couvreur⁴, Laure Van Breda⁴, Florence Bourgeois⁵, Kato Speleman⁵, Sam Klein⁶, Johan Van Laethem⁷, Gill Verstappen⁸, Ayse Sumeyra Dereli¹, Seung-Jun Yoo⁹, Hai Zhou¹, Thuc Nguyen Dan Do¹⁰, Dirk Jochmans¹⁰, Lies Laenen¹¹, Yves Debaveye¹², Paul De Munter¹³, Jan Gunst¹², Mark Jorissen¹⁴, Katrien Lagrou¹⁵, Philippe Meersseman¹³, Johan Neyts¹⁰, Dietmar Rudolf Thal¹⁶, Vedat Topsakal⁸, Christophe Vandenbriele¹⁷, Joost Wauters¹³, Peter Mombaerts¹⁸, Laura Van Gerven¹⁹

Affiliations

¹ Max Planck Research Unit for Neurogenetics, Frankfurt, Germany.
² Department of Neurosciences, Experimental Otorhinolaryngology, Rhinology Research, KU Leuven, Leuven, Belgium.
³ Department of Otorhinolaryngology, Head and Neck Surgery, University Hospitals Leuven, Leuven, Belgium; Department of Microbiology, Immunology and Transplantation, Allergy and Clinical Immunology Research Group, KU Leuven, Leuven, Belgium.
⁴ Department of Otorhinolaryngology, Head and Neck Surgery, University Hospitals Leuven, Leuven, Belgium.
⁵ Department of Otorhinolaryngology, Head and Neck Surgery, AZ Sint-Jan Brugge-Oostende AV, Bruges, Belgium.
⁶ Department of Neurosurgery, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Brussels, Belgium.
⁷ Department of Infectious Diseases, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Brussels, Belgium.
⁸ Department of Otorhinolaryngology - Head and Neck Surgery, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Brussels, Belgium.
⁹ Max Planck Research Unit for Neurogenetics, Frankfurt, Germany; Department of Life Science, College of Natural Sciences, Hanyang University, Seoul, Republic of Korea.
¹⁰ Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, KU Leuven, Leuven, Belgium.
¹¹ Department of Laboratory Medicine & National Reference Center for Respiratory Pathogens, University Hospitals Leuven, Leuven, Belgium.
¹² Intensive Care Medicine, University Hospitals Leuven, Leuven, Belgium; Department of Cellular and Molecular Medicine, Laboratory of Intensive Care Medicine, KU Leuven, Leuven, Belgium.
¹³ Department of General Internal Medicine, University Hospitals Leuven, Leuven, Belgium; Department of Microbiology, Immunology and Transplantation, Laboratory for Clinical Infectious and Inflammatory Disorders, KU Leuven, Leuven, Belgium.
¹⁴ Department of Neurosciences, Experimental Otorhinolaryngology, Rhinology Research, KU Leuven, Leuven, Belgium; Department of Otorhinolaryngology, Head and Neck Surgery, University Hospitals Leuven, Leuven, Belgium.
¹⁵ Department of Laboratory Medicine & National Reference Center for Respiratory Pathogens, University Hospitals Leuven, Leuven, Belgium; Department of Microbiology, Immunology and Transplantation, Laboratory of Clinical Bacteriology and Mycology, KU Leuven, Leuven, Belgium.
¹⁶ Department of Pathology, University Hospitals Leuven, Leuven, Belgium; Laboratory of Neuropathology, Department of Imaging & Pathology and Leuven Brain Institute, KU Leuven, Leuven, Belgium.
¹⁷ Department of Cardiovascular Diseases, University Hospitals Leuven, Leuven, Belgium; Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium.
¹⁸ Max Planck Research Unit for Neurogenetics, Frankfurt, Germany. Electronic address: [email protected].
¹⁹ Department of Neurosciences, Experimental Otorhinolaryngology, Rhinology Research, KU Leuven, Leuven, Belgium; Department of Otorhinolaryngology, Head and Neck Surgery, University Hospitals Leuven, Leuven, Belgium; Department of Microbiology, Immunology and Transplantation, Allergy and Clinical Immunology Research Group, KU Leuven, Leuven, Belgium. Electronic address: [email protected].

Abstract

Can SARS-CoV-2 hitchhike on the olfactory projection and take a direct and short route from the nose into the brain? We reasoned that the neurotropic or neuroinvasive capacity of the virus, if it exists, should be most easily detectable in individuals who died in an acute phase of the infection. Here, we applied a postmortem bedside surgical procedure for the rapid procurement of tissue, blood, and cerebrospinal fluid samples from deceased COVID-19 patients infected with the Delta, Omicron BA.1, or Omicron BA.2 variants. Confocal imaging of sections stained with fluorescence RNAscope and immunohistochemistry afforded the light-microscopic visualization of extracellular SARS-CoV-2 virions in tissues. We failed to find evidence for viral invasion of the parenchyma of the olfactory bulb and the frontal lobe of the brain. Instead, we identified anatomical barriers at vulnerable interfaces, exemplified by perineurial olfactory nerve fibroblasts enwrapping olfactory axon fascicles in the lamina propria of the olfactory mucosa.

Keywords: COVID-19; Coronavirus; Delta; Omicron; RNAscope; SARS-CoV-2; Virchow-Robin space; blood-brain barrier; brain parenchyma; frontal lobe; glia limitans perivascularis; leptomeninges; neuroinvasion; neurotropism; olfactory; olfactory bulb; olfactory sensory neuron; perineurial olfactory nerve fibroblast.

MeSH terms

Brain
COVID-19*
Humans
Olfactory Bulb
SARS-CoV-2*
Smell