Expression levels of taste genes, TAS1R1, TAS1R2 and TAS1R3 among SARS-CoV-2 patients

Abstract Background The most common symptoms of COVID-19 infection include fever, myalgia, cough, dyspnea, and loss of smell and taste. Some studies have suggested that a COVID-19-related reduction in taste receptor expression may lead to the loss of taste. Therefore, this study aimed to assess the expression levels of taste receptor genes in COVID-19 patients. Gene expression levels of TAS1R1, TAS1R2, and TAS1R3 were analyzed in 100 COVID-19 patients (50 with loss of taste and 50 without) and 50 SARS-CoV-2 RT-qPCR-negative individuals. Methods 150 nasopharyngeal swab samples were collected from Iranian COVID-19 patients (50 with loss of taste and 50 without) and SARS-CoV-2 negative persons as a control group and evaluated for TAS1R1, TAS1R2, and TAS1R3 gene expression using mRNA measurement. Gene expression was evaluated using two-step real-time PCR, and RPLP0 was used as a reference gene. Result The expression levels of taste genes did not show a significant difference between healthy individuals and infected patients with and without loss of taste. There was also no significant difference between the gene expression levels in each group. Conclusions Although our findings were not statistically significant, temporary ageusia may be attributed to the high replication rate of SARS-CoV-2 in infected gustatory cells within the taste buds. This replication could induce inflammation and potentially lead to cell destruction.