Regional Differences in Taste Responsiveness: Effect of Stimulus and Tasting Mode

Previous studies have shown that there are differences in taste responses between various regions of the tongue. Most of those studies used a controlled "passive" tasting mode due to the nature of investigation. However, food is rarely tasted in a passive manner. In addition, recent studies have suggested that humans can taste maltooligosaccharides (MOS) and that the gustatory detection of MOS is independent of the known sweet receptor. It is unknown whether regional differences in responsiveness to MOS exist. This study was set up to revisit previous work by investigating the effects of tasting mode ("passive" vs. "active") on regional differences in taste responsiveness to sucrose, monopotassium glutamate (MPG), and quinine, while also investigating potential regional differences in responsiveness to MOS. The stimuli were applied to 1 of 4 target areas, the left and right sides of the front and back of the tongue, using cotton-tipped swabs. In the passive tasting condition, the front of the tongue was found to be more responsive to both sucrose and MOS, but no regional differences were seen for quinine and MPG. In contrast, in the active tasting condition, the back of the tongue was found to be more responsive to quinine and MPG, but no differences were found for sucrose or MOS. These findings indicate that there are regional differences in taste responsiveness between the front and back of the tongue and that regional responsiveness is dependent on stimulus and tasting mode

Identifying genetic variants underlying medication-induced osteonecrosis of the jaw in cancer and osteoporosis: a case control study

Background Bisphosphonate-induced osteonecrosis of the jaw (BRONJ) presents with a typical pattern of jaw necrosis in patients who have been prescribed bisphosphonates (BPs) and other antiangiogenetic drugs to treat osteoporosis or bone-related complications of cancer. Methods This study divided 38 patients with BRONJ into two groups according to the prescribing causes: cancer (n = 13) and osteoporosis (n = 25), and underwent whole exome sequencing and compared them with normal controls (n = 90). To identify candidate genes and variants, we conducted three analyses: a traditional genetic model, gene-wise variant score burden, and rare-variant analysis methods. Results The stop-gain mutation (rs117889746) of the PZP gene in the BRONJ cancer group was significantly identified in the additive trend model analysis. In the cancer group, ARIDS, HEBP1, LTBP1, and PLVAP were identified as candidate genes. In the osteoporosis group, VEGFA, DFFA, and FAM193A genes showed a significant association. No significant genes were identified in the rare-variant analysis pipeline. Biologically accountable functions related to BRONJ occurrence-angiogenesis-related signaling (VEGFA and PLVAP genes), TGF-β signaling (LTBP1 and PZP genes), heme toxicity (HEBP1) and osteoblast maturation (ARIDS)-were shown in candidate genes. Conclusion This study showed that the candidate causative genes contributing to the development of BRONJ differ according to the BP dose and background disease.This work was supported by the Education and Research Encouragement Fund of Seoul National University Hospital and the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF2018R1D1A1A02086109). There are no conficts of interest to declare

More than smell - COVID-19 is associated with severe impairment of smell, taste, and chemesthesis

Recent anecdotal and scientific reports have provided evidence of a link between COVID-19 and chemosensory impairments such as anosmia. However, these reports have downplayed or failed to distinguish potential effects on taste, ignored chemesthesis, generally lacked quantitative measurements, were mostly restricted to data from single countries. Here, we report the development, implementation and initial results of a multi-lingual, international questionnaire to assess self-reported quantity and quality of perception in three distinct chemosensory modalities (smell, taste, and chemesthesis) before and during COVID-19. In the first 11 days after questionnaire launch, 4039 participants (2913 women, 1118 men, 8 other, ages 19-79) reported a COVID-19 diagnosis either via laboratory tests or clinical assessment. Importantly, smell, taste and chemesthetic function were each significantly reduced compared to their status before the disease. Difference scores (maximum possible change+/-100) revealed a mean reduction of smell (-79.7+/- 28.7, mean+/- SD), taste (-69.0+/- 32.6), and chemesthetic (-37.3+/- 36.2) function during COVID-19. Qualitative changes in olfactory ability (parosmia and phantosmia) were relatively rare and correlated with smell loss. Importantly, perceived nasal obstruction did not account for smell loss. Furthermore, chemosensory impairments were similar between participants in the laboratory test and clinical assessment groups. These results show that COVID-19-associated chemosensory impairment is not limited to smell, but also affects taste and chemesthesis. The multimodal impact of COVID-19 and lack of perceived nasal obstruction suggest that SARS-CoV-2 infection may disrupt sensory-neural mechanisms

Taste perception of cyclic oligosaccharides: α, β, and γ cyclodextrins

Abstract Oligosaccharides, a subclass of complex carbohydrates, occur both naturally in foods and as a result of oral starch digestion. We have previously shown that humans can taste maltooligosaccharides (MOS) and that their detection is independent of the canonical sweet taste receptor. While MOSs most commonly occur in a linear form, they can also exist in cyclic structures, referred to as cyclodextrins (CD). The aim of this study was to investigate how the structure of the MOS backbone (i.e. cyclic form) and the size (i.e. degree of polymerization; DP) affect their taste perception. We tested taste detection of cyclodextrins with DP of 6, 7, and 8 (i.e. α-, β-, and γ-CD, respectively) in the presence and absence of lactisole, a sweet receptor antagonist. We found that subjects could detect the taste of cyclodextrins in aqueous solutions at a significant level (P &amp;lt; 0.05), but were not able to detect them in the presence of lactisole (P &amp;gt; 0.05). These findings suggest that the cyclodextrins, unlike their linear analogs, are ligands of the human sweet taste receptor, hT1R2/hT1R3. Study findings are discussed in terms of how chemical structures may contribute to tastes of saccharides.</jats:p