ABSTRACT
Background: Bitter taste-sensing type 2 receptor (T2Rs or TAS2Rs) found on ciliated epithelial cells and solitary chemosensory cells have a role in respiratory tract immuni-ty. T2Rs have shown protection against SARS-CoV-2 by enhancing the innate immune response. The purpose of this review is to outline the current sphere of knowledge re-garding this association. Method(s): A narrative review of the literature was done by searching (T2R38 OR bitter taste receptor) AND (COVID-19 OR SARS-CoV-2) keywords in PubMed and google scholar. Result(s): T2R38, an isoform of T2Rs encoded by the TAS2R38 gene, may have a potential association between phenotypic expression of T2R38 and prognosis of COVID-19. Current studies suggest that due to different genotypes and widespread distributions of T2Rs within the respiratory tract and their role in innate immunity, treatment protocols for COVID-19 and other respiratory diseases may change accordingly. Based on the phenotypic expression of T2R38, it varies in innate immunity and host response to respiratory infection, systemic symptoms and hospitalization. Conclusion(s): This review reveals that patients' innate immune response to SARS-COV-2 could be influenced by T2R38 receptor allelic variations.Copyright © 2023, Avicenna Journal of Medical Biotechnology.
ABSTRACT
Objective: Hyposmia and anosmia are the most frequent complaints of patients with COVID-19. It can disappear after a short time or can last for an unknown period. Finding a suitable treatment for restoring the patients' smell. The objective of this study is to review the effects of numerous types of corticoids on COVID-19-induced hyposmia and anosmia. Method(s): A narrative literature review was performed to analyze the effects of different forms of corticosteroids in various dosages for the treatment of COVID-19-induced hyposmia and anosmia. Result(s): There is not a lot of data on the effects of corticosteroids on COVID-19-induced hyposmia and anosmia;however, despite little evidence for the efficacy of these drugs in hyposmia and anosmia caused by COVID-19, their effect in improving these symptoms whether in oral or nasal spray forms has been reported in recent literature. Most of the studies show that corticosteroids, whether nasal or systemic, are not as effective as they are thought to be. Conclusion(s): Using topical corticosteroids as nasal sprays or systemic corticosteroids cannot help to improve the patient's ability to smell. These methods were sometimes mixed with other methods such as olfactory training to improve the patient's olfactory sense. However, the results of the studies showed diversity in the efficacies of each treatment plan. In most of the studies which used olfactory training along with corticosteroid therapy as a therapy for hyposmia/anosmia induced by COVID-19, olfactory training showed a better result. Copyright@Author(s).