TY - JOUR
T1 - Postmortem Assessment of Olfactory Tissue Degeneration and Microvasculopathy in Patients with COVID-19
AU - Ho, Cheng Ying
AU - Salimian, Mohammad
AU - Hegert, Julia
AU - O'Brien, Jennifer
AU - Choi, Sun Gyeong
AU - Ames, Heather
AU - Morris, Meaghan
AU - Papadimitriou, John C.
AU - Mininni, Joseph
AU - Niehaus, Peter
AU - Burke, Allen
AU - Canbeldek, Leyla
AU - Jacobs, Jonathan
AU - Larocque, Autumn
AU - Patel, Kavi
AU - Rice, Kathryn
AU - Li, Ling
AU - Johnson, Robert
AU - Lefevre, Alexandra
AU - Blanchard, Thomas
AU - Shaver, Ciara M.
AU - Moyer, Ann
AU - Drachenberg, Cinthia
N1 - Publisher Copyright:
© 2022 American Medical Association. All rights reserved.
PY - 2022/6
Y1 - 2022/6
N2 - Importance: Loss of smell is an early and common presentation of COVID-19 infection. Although it has been speculated that viral infection of olfactory neurons may be the culprit, it is unclear whether viral infection causes injuries in the olfactory bulb region. Objective: To characterize the olfactory pathology associated with COVID-19 infection in a postmortem study. Design, Setting, and Participants: This multicenter postmortem cohort study was conducted from April 7, 2020, to September 11, 2021. Deceased patients with COVID-19 and control individuals were included in the cohort. One infant with congenital anomalies was excluded. Olfactory bulb and tract tissue was collected from deceased patients with COVID-19 and appropriate controls. Histopathology, electron microscopy, droplet digital polymerase chain reaction, and immunofluorescence/immunohistochemistry studies were performed. Data analysis was conducted from February 7 to October 19, 2021. Main Outcomes and Measures: (1) Severity of degeneration, (2) losses of olfactory axons, and (3) severity of microvasculopathy in olfactory tissue. Results: Olfactory tissue from 23 deceased patients with COVID-19 (median [IQR] age, 62 [49-69] years; 14 men [60.9%]) and 14 control individuals (median [IQR] age, 53.5 [33.25-65] years; 7 men [50%]) was included in the analysis. The mean (SD) axon pathology score (range, 1-3) was 1.921 (0.569) in patients with COVID-19 and 1.198 (0.208) in controls (P <.001), whereas axon density was 2.973 (0.963) × 104/mm2in patients with COVID-19 and 3.867 (0.670) × 104/mm2in controls (P =.002). Concomitant endothelial injury of the microvasculature was also noted in olfactory tissue. The mean (SD) microvasculopathy score (range, 1-3) was 1.907 (0.490) in patients with COVID-19 and 1.405 (0.233) in control individuals (P <.001). Both the axon and microvascular pathology was worse in patients with COVID-19 with smell alterations than those with intact smell (mean [SD] axon pathology score, 2.260 [0.457] vs 1.63 [0.426]; P =.002; mean [SD] microvasculopathy score, 2.154 [0.528] vs 1.694 [0.329]; P =.02) but was not associated with clinical severity, timing of infection, or presence of virus. Conclusions and Relevance: This study found that COVID-19 infection is associated with axon injuries and microvasculopathy in olfactory tissue. The striking axonal pathology in some cases indicates that olfactory dysfunction in COVID-19 infection may be severe and permanent.
AB - Importance: Loss of smell is an early and common presentation of COVID-19 infection. Although it has been speculated that viral infection of olfactory neurons may be the culprit, it is unclear whether viral infection causes injuries in the olfactory bulb region. Objective: To characterize the olfactory pathology associated with COVID-19 infection in a postmortem study. Design, Setting, and Participants: This multicenter postmortem cohort study was conducted from April 7, 2020, to September 11, 2021. Deceased patients with COVID-19 and control individuals were included in the cohort. One infant with congenital anomalies was excluded. Olfactory bulb and tract tissue was collected from deceased patients with COVID-19 and appropriate controls. Histopathology, electron microscopy, droplet digital polymerase chain reaction, and immunofluorescence/immunohistochemistry studies were performed. Data analysis was conducted from February 7 to October 19, 2021. Main Outcomes and Measures: (1) Severity of degeneration, (2) losses of olfactory axons, and (3) severity of microvasculopathy in olfactory tissue. Results: Olfactory tissue from 23 deceased patients with COVID-19 (median [IQR] age, 62 [49-69] years; 14 men [60.9%]) and 14 control individuals (median [IQR] age, 53.5 [33.25-65] years; 7 men [50%]) was included in the analysis. The mean (SD) axon pathology score (range, 1-3) was 1.921 (0.569) in patients with COVID-19 and 1.198 (0.208) in controls (P <.001), whereas axon density was 2.973 (0.963) × 104/mm2in patients with COVID-19 and 3.867 (0.670) × 104/mm2in controls (P =.002). Concomitant endothelial injury of the microvasculature was also noted in olfactory tissue. The mean (SD) microvasculopathy score (range, 1-3) was 1.907 (0.490) in patients with COVID-19 and 1.405 (0.233) in control individuals (P <.001). Both the axon and microvascular pathology was worse in patients with COVID-19 with smell alterations than those with intact smell (mean [SD] axon pathology score, 2.260 [0.457] vs 1.63 [0.426]; P =.002; mean [SD] microvasculopathy score, 2.154 [0.528] vs 1.694 [0.329]; P =.02) but was not associated with clinical severity, timing of infection, or presence of virus. Conclusions and Relevance: This study found that COVID-19 infection is associated with axon injuries and microvasculopathy in olfactory tissue. The striking axonal pathology in some cases indicates that olfactory dysfunction in COVID-19 infection may be severe and permanent.
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U2 - 10.1001/jamaneurol.2022.0154
DO - 10.1001/jamaneurol.2022.0154
M3 - Article
C2 - 35404378
AN - SCOPUS:85128365272
SN - 2168-6149
VL - 79
SP - 544
EP - 553
JO - JAMA neurology
JF - JAMA neurology
IS - 6
ER -