Taste receptors in chronic rhinosinusitus, what is the evidence? A systematic review

Abstract

Background Bitter and sweet taste receptors (T2Rs and T1Rs), respectively, are involved in the innate immune response of the sinonasal cavity and associated with chronic rhinosinusitis (CRS). Growing evidence suggests extraoral TRs as relevant biomarkers, but the current understanding is incomplete. This systematic review synthesizes current evidence of extraoral taste receptors in CRS. Methods PubMed, Embase, Cochrane, Web of Science, and Scopus were reviewed in accordance with Preferred Reporting Items for Systemic Reviews and Meta‐Analyses guidelines and included studies of genotypic and phenotypic T2R/T1R status in CRS patients. Results Twenty‐two studies with 3845 patients were included. Seventeen studies evaluated genotype and 10 evaluated taste phenotypes. Four of 6 studies examining the haplotype distribution of the T2R, TAS2R38, demonstrated increased AVI/AVI haplotype (“nontaster”) frequency in CRS. Meanwhile, 2 studies demonstrated decreased bitter sensitivity in CRS with nasal polyposis (CRSwNP), whereas 3 other studies reported decreased bitter sensitivity only in CRS without nasal polyposis (CRSsNP). Findings regarding sweet sensitivity were mixed. Three studies with cystic fibrosis patients (n = 1393) were included. Studies investigating the association between clinical outcomes and TAS2R38 alleles were limited, but the nonfunctional combination of AVI/AVI was associated with increased utilization of sinus surgery and, in CRSsNP patients, with poorer improvement of symptoms postoperatively. Conclusion Both genotypic and phenotypic assessments of T2Rs suggest a potential association with CRS, particularly CRSsNP. However, limited evidence and mixed conclusions cloud the role of T2Rs in CRS. Future investigations should aim to increase diverse populations, broaden institutional diversity, examine T1Rs, and utilize uniform assessments.

Genetic variations in bitter and sweet taste receptors in Taiwanese patients with chronic rhinosinusitis

“…Recently, a systematic review explored the association of taste receptors with CRS 8 . The review collected 17 studies that had investigated the genotypes of taste receptors and concluded that TAS2R s may have a potential association with CRS, particularly CRSsNP.…”

“…Recently, a systematic review explored the association of taste receptors with CRS. 8 The review collected 17 studies that had investigated the genotypes of taste receptors and concluded that TAS2Rs may have a potential association with CRS, particularly CRSsNP. All 17 of those studies evaluated Western populations, so it was suggested that future investigations involving more diverse institutions and populations be conducted.…”

Scientific Advancements That Empower Us to Understand CRS Pathophysiology

“…Wang et al 29 SNPs in the bitter taste receptor gene TAS2R38 appear to be associated with CRS. 25,26 20 Whole genome sequencing techniques, such as NGS, are becoming more increasingly available and provide a powerful tool to generate "big data," which offer a unique opportunity to gain insights into the mechanisms of complex diseases such as CRSwNP. Proteomics using mass spectrometry and transcriptomics, such as RNA sequencing (RNA-seq), are newer techniques that allow us to gain additional insights and are also becoming more accessible.…”

Year in review: 2021 IFAR article summary

“…Meanwhile, attempting to elucidate the clinical relevance of extraoral taste receptors in CRS, a systematic review studies with genotypic and phenotypic taste receptor profiles analysis concluded that there is mounting evidence of an association of bitter taste receptors in CRS, particularly in CRSwNP; however, limited evidence and mixed conclusions highlight the need for further study. 43 Finally, Deng et al 44 examined differences in the innervation and the cholinergic receptor patterns in solitary chemosensory cells (SCCs) between inferior turbinate and nasal polyp tissue, and their findings suggested that the lack of trigeminal innervation in nasal polyp tissue may be associated with the SCC proliferation seen in nasal polyps in the setting of type 2 inflammation.…”

“…Both studies give further credence to a potential underlying difference in innate immunity that is mediated by bitter and sweet taste receptors in patients with CRS. Meanwhile, attempting to elucidate the clinical relevance of extraoral taste receptors in CRS, a systematic review studies with genotypic and phenotypic taste receptor profiles analysis concluded that there is mounting evidence of an association of bitter taste receptors in CRS, particularly in CRSwNP; however, limited evidence and mixed conclusions highlight the need for further study 43 . Finally, Deng et al 44 .…”