Epipharyngeal Abrasive Therapy Down-regulates the Expression of SARS-CoV-2 Entry Factors ACE2 and TMPRSS2

Background: The epipharynx, with its high expression of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) entry factors angiotensinconverting enzyme 2 (ACE2) and transmembrane protease, serine 2 (TMPRSS2), is a primary target for SARS-CoV-2 replication in the early stage of Coronavirus Disease 19 (COVID-19). Epipharyngeal abrasive therapy (EAT) is a treatment for epipharyngitis in Japan which involves applying zinc chloride to the epipharyngeal mucosa. In this study, we evaluated the expression patterns of ACE2 and TMPRSS2 in tissue samples from patients before and after EAT. Patients and Methods: The study subjects were seven patients that had not been treated with EAT and 11 patients that had. For immunohistochemical assessment of the epipharyngeal mucosa, the staining intensity of ACE2 and TMPRSS2 was described as an immunohistochemical score (IHC score). Results: The IHC scores for ACE2 and TEMPRSS2 in the EAT-treated group were 3.40-fold and 1.81-fold lower, respectively, than those in the non-treated group (p=0.0208 and p=0.0244, respectively). Conclusion: EAT down-regulates the expression of SARS-CoV-2 entry factors ACE2 and TMPRSS2. Thus, EAT has potential as a novel COVID-19 preventative method.

Automated summary

This study evaluated the expression patterns of ACE2 and TMPRSS2 in tissue samples before and after epipharyngeal abrasive therapy (EAT). The results showed that the expression of ACE2 and TMPRSS2 was decreased in the EAT-treated group compared to the non-treated group. Therefore, EAT has the potential to be a novel preventive method for COVID-19.