Editor’s Pick: Mouse model sheds light on mechanisms for smell loss in COVID-19

Reviewing Editor Matthew Grubb, Ph.D. selected this paper and explains why he considers it noteworthy.

Smell loss, or anosmia, remains a prominent but mechanistically mysterious feature of COVID-19. In this careful study of SARS-CoV-2-induced olfactory system pathology, which the reviewers described as "good quality" and as providing "convincing and solid evidence," Martin-Lopez et al. use a specific mouse model to illuminate potential causes of COVID-19-associated anosmia.

In mice expressing the human SARS-CoV-2 receptor ACE2 under the control of the epithelial K18 promoter, the authors find evidence for infection and cellular pathology in projection neurons of central olfactory areas, but not in the sensory neurons of the nasal epithelium. Great care should, of course, be taken when extrapolating from mouse models to the clinic. However, this study supports existing evidence for a non-olfactory route taken by SARS-CoV-2 into the brain, and highlights cell types that may be crucial in better understanding anosmia in COVID-19.

Read the full article:

Inflammatory Response and Defects on Myelin Integrity in the Olfactory System of K18hACE2 Mice Infected with SARS-CoV-2
Eduardo Martin-Lopez, Bowen Brennan, Tianyang Mao, Natalie Spence, Sarah J. Meller, Kimberly Han, Nawal Yahiaoui, Chelsea Wang, Akiko Iwasaki, and Charles A. Greer