ACE2 and TAS2R38 receptor expression in pediatric and adult patients in the nasal and oral cavity.

ABSTRACT

Objective: To investigate differences in angiotensin-converting-enzyme-2 (ACE2) and bitter taste receptor (TAS2R38) expression between patient age groups and comorbidities to characterize the pathophysiology of coronavirus 19(COVID-19) pandemic. ACE2 is the receptor implicated to facilitate SARS-CoV-2 infections and levels of expression may correlate to the severity of COVID-19 infection. TAS2R38 has many non-gustatory roles in disease, with some evidence of severe COVID-19 disease in certain receptor phenotypes. Methods: We conducted a prospective cohort study and collected nasal and lingual tissue from healthy pediatric (n = 22) and adult (n = 25) patients undergoing general anesthesia for elective procedures. RNA isolation and qPCR were performed with primers targeting ACE2 and TAS2R38. Results: A total of 25 adult (52% male; 44% obese) and 22 pediatric (50% male; 36% obese) patients were enrolled, pediatric tissue had 43% more nasal ACE2 RNA expression than adults with a median fold change of 0.69 (IQR 0.37, 0.98) in adults and 0.99 (IQR 0.74, 1.43) in children (p < .05). There were no differences between the age groups in ACE2 expression of lingual tissue (p = .14) or TAS2R38 expression collected from either nasal (p = 049) or lingual tissue (p = .49). Stratifying for obesity yielded similar differences between nasal ACE2 expression between adults and children with median fold change of 0.56 (IQR 0.32, 0.87) in adults and 1.0 (IQR 0.82, 1.52) in children (p < .05). Conclusions: ACE2 receptor expression is higher in nasal tissue collected from children compared to adults, suggesting COVID-19 infectivity is more complicated than ACE2 and TAS2R38 mRNA expression. Level of Evidence NA.