Expressão de ECA2 e TMPRSS2 nas células do epitélio oral e o papel da saliva na pandemia da COVID-19

Abstract

This study aims to review the relevant role saliva plays in transmission, monitoring and diagnosis of COVID-19, through the relationship between the new coronavirus and ACE2 and TMPRSS2 receptors found in the oral cavity. The literature review was carried by accessing the following data base, from 2003 to 2022: Pubmed, Medline, ResearchGate and Wiley Online Library. The review emphasized papers published from january 2020 on (the beginning of the pandemic). The literature review allowed to verify that SARS-CoV-2 uses ACE2 and TMPRSS2 as functional receptors, since it needs both to bind and cleave its spike protein. The expression of ACE2 and TMPRSS2 in the tongue, lips, cheeks cells and salivary glands make the oral cavity a potential gateway to the new coronavirus. Also, it allows its transmission through the saliva after virus replication in those structures. Furthermore, transmission can take place in pre, symptomatic and post symptomatic period, mainly by aerosols, direct or indirectly. On the other hand, we also noticed saliva plays a relevant role with respect to diagnosis and monitoring of the disease. Saliva testing provides a reliable, consistent and similar results when compared to nasopharyngeal swabs, and also allows a viral detection in different phases of the disease unlike other methods. In adiction to make possible the self saliva collection by patient, saliva testing is non-invasive, affordable, less uncomfortable and more safe in comparison to other methods, because it reduces the exposure of health professionals to the contamination. Because the pandemic is too recent it claims for more researchs aiming to consolidate the link between the presence of receptors in the oral epithelium and new oronavirus in saliva, especially regarding to variants and its constant mutation in its spike protein, increasing infectivity. In addition, severe biosecurity measures must be applied during dental practice focusing on reduce the risk of contamination through saliva, due to proximity between patient and dentist.