A taste alteration-related scale assesses megestrol to improve chemotherapy-induced anorexia

PURPOSE

We evaluated the efficacy of megestrol in improving chemotherapy-related anorexia by analyzing the related scales of taste alteration.

METHODS

We conducted the current study on a group of advanced patients with cancer with two or more chemotherapy cycles. The chemotherapy-induced taste alteration scale (CiTAs) scale helped assess the megestrol effects on basic taste perception, aversive taste changes, unpleasant symptoms, and associated concerns. Furthermore, the Short Nutritional Assessment Questionnaire scale (SNAQ) helped measure the impact of megestrol on malnutrition likelihood in patients experiencing chemotherapy-induced anorexia. The World Health Organization Quality of Life (WHOQOL)-BREF Scale was used to evaluate the quality of life of participants, producing scores related to physical health, psychological well-being, environmental factors, and social relationships.

RESULTS

The CiTAs scale assessment indicated that administering megestrol significantly enhanced taste perception among advanced patients with cancer undergoing chemotherapy. Notably, the megestrol group patients showed significantly higher Short Nutritional Assessment Questionnaire (SNAQ) scores than the control group. The megestrol group patients also exhibited higher physiological (PHYS) scores than their control group counterparts. However, this distinction was not statistically significant. The study findings indicate that patients who received megestrol demonstrated significantly higher scores in psychological (PSYCH) and environmental(ENVIR) domains than the control group. Furthermore, megestrol administration was associated with significantly elevated SOCIL and ENVIR levels in patients.

CONCLUSION

The proficient efficacy evaluation of megestrol in enhancing appetite, mitigating malnutrition likelihood, and improving the quality of life of chemotherapy-induced anorexic patients can be achieved through taste-related scales.

Bitter taste receptor activation by cholesterol and an intracellular tastant

Bitter taste sensing is mediated by type 2 taste receptors (TAS2Rs (also known as T2Rs)), which represent a distinct class of G-protein-coupled receptors1. Among the 26 members of the TAS2Rs, TAS2R14 is highly expressed in extraoral tissues and mediates the responses to more than 100 structurally diverse tastants2-6, although the molecular mechanisms for recognizing diverse chemicals and initiating cellular signalling are still poorly understood. Here we report two cryo-electron microscopy structures for TAS2R14 complexed with Ggust (also known as gustducin) and Gi1. Both structures have an orthosteric binding pocket occupied by endogenous cholesterol as well as an intracellular allosteric site bound by the bitter tastant cmpd28.1, including a direct interaction with the α5 helix of Ggust and Gi1. Computational and biochemical studies validate both ligand interactions. Our functional analysis identified cholesterol as an orthosteric agonist and the bitter tastant cmpd28.1 as a positive allosteric modulator with direct agonist activity at TAS2R14. Moreover, the orthosteric pocket is connected to the allosteric site via an elongated cavity, which has a hydrophobic core rich in aromatic residues. Our findings provide insights into the ligand recognition of bitter taste receptors and suggest activities of TAS2R14 beyond bitter taste perception via intracellular allosteric tastants.

Efficacy and Tolerability of Gefapixant for Treatment of Refractory or Unexplained Chronic Cough: A Systematic Review and Dose-Response Meta-Analysis

Importance

Gefapixant represents an emerging therapy for patients with refractory or unexplained chronic cough.

Objective

To evaluate the efficacy and tolerability of gefapixant for the treatment of adults with refractory or unexplained chronic cough.

Data Sources

MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and Web of Science from November 2014 to July 2023.

Study Selection

Two reviewers independently screened for parallel and crossover randomized clinical trials (RCTs) that compared, in patients with refractory or unexplained chronic cough, either gefapixant with placebo, or 2 or more doses of gefapixant with or without placebo.

Data Extraction and Synthesis

Two reviewers independently extracted data. A frequentist random-effects dose-response meta-analysis or pairwise meta-analysis was used for each outcome. The GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach was used to rate the certainty in whether patients would perceive the effects as important (greater than the minimal important difference [MID]) or small (less than the MID).

Main Outcomes and Measures

Cough frequency (measured using the VitaloJAK cough monitor; MID, 20%), cough severity (measured using the 100-mm visual analog scale [VAS]; higher score is worse; MID, 30 mm), cough-specific quality of life (measured using the Leicester Cough Questionnaire [LCQ]; score range, 3 [maximal impairment] to 21 [no impairment]; MID, 1.3 points), treatment-related adverse events, adverse events leading to discontinuation, and taste-related adverse events.

Results

Nine RCTs including 2980 patients were included in the primary analysis. Compared with placebo, gefapixant (45 mg twice daily) had small effects on awake cough frequency (17.6% reduction [95% CI, 10.6%-24.0%], moderate certainty), cough severity on the 100-mm VAS (mean difference, -6.2 mm [95% CI, -4.1 to -8.4]; high certainty), and cough-specific quality of life on the LCQ (mean difference, 1.0 points [95% CI, 0.7-1.4]; moderate certainty). Compared with placebo, gefapixant (45 mg twice daily) probably caused an important increase in treatment-related adverse events (32 more per 100 patients [95% CI, 13-64 more], moderate certainty) and taste-related adverse events (32 more per 100 patients [95% CI, 22-46 more], high certainty). High-certainty evidence suggests that gefapixant (15 mg twice daily) had small effects on taste-related adverse events (6 more per 100 patients [95% CI, 5-8 more]).

Conclusions and Relevance

Compared with placebo, gefapixant (45 mg orally twice daily) led to modest improvements in cough frequency, cough severity, and cough-specific quality of life but increased taste-related adverse events.

The Effects of Adding a Gel-Alike Curcuma longa L. Suspension as Color Agent on Some Quality and Sensory Properties of Yogurt

Color is an important characteristic of food products. This characteristic is related to consumer acceptability. To use the entire rhizome of Curcuma longa (CL) as a food colorant, a novel gel alike stable suspension (CLS) was previously developed using cellulose nanofibers (CNFs). Therefore, the present study was conducted to evaluate the CLS as a color additive on a stirred yogurt. Three concentrations of CLS were studied (0.1, 0.125, and 0.15 wt. %) and compared to yogurt without CLS. The obtained yogurts were characterized through the determination of pH, titratable acidity, syneresis, color and curcumin content after 1, 7, 14, and 21 days of storage. Additionally, rheological and sensory measurements were performed on the samples after one day of storage. Results show that the addition of CLS does not affect the pH and titratable acidity of the samples, but all the yogurts showed an increase in their syneresis during the storage time, showing a breakdown of the gel structure. Furthermore, the CLS suspension has the ability to impart a yellow color to yogurts, a characteristic that was stable during storage. Finally, the addition of 1 wt. % or 1.25 wt. % of CLS allows the development of a yogurt with adequate sensory perception.

The Influence of Hop Phenolic Compounds on Dry Hopping Beer Quality

Background: The article considers the phenolic hop compounds’ effect on the quality indicators of finished beer. The topic under consideration is relevant since it touches on the beer matrix colloidal stability when compounds with potential destabilizing activity are introduced into it from the outside. Methods: The industrial beer samples’ quality was assessed by industry-accepted methods and using instrumental analysis methods (high-performance liquid chromatography methods—HPLC). The obtained statistical data were processed by the Statistics program (Microsoft Corporation, Redmond, WA, USA, 2006). Results: The study made it possible to make assumptions about the functional dependence of the iso-α-bitter resins and isoxanthohumol content in beer samples. Mathematical analysis indicate interactions between protein molecules and different malted grain and hop compounds are involved in beer structure, in contrast to dry hopped beer, where iso-a-bitter resins, protein, and coloring compounds were significant, with a lower coefficient of determination. The main role of rutin in the descriptor hop bitterness has been established in kettle beer hopping technology, and catechin in dry beer hopping technology, respectively. The important role of soluble nitrogen and β-glucan dextrins in the perception of sensory descriptors of various technologies’ beers, as well as phenolic compounds in relation to the formation of bitterness and astringency of beer of classical technology and cold hopping, has been shown. Conclusions: The obtained mathematical relationships allow predicting the resulting beer quality and also make it possible to create the desired flavor profiles.

Additive Effects of L-Ornithine on Preferences to Basic Taste Solutions in Mice

In addition to the taste receptors corresponding to the six basic taste qualities-sweet, salty, sour, bitter, umami, and fatty-another type of taste receptor, calcium-sensing receptor (CaSR), is found in taste-bud cells. CaSR is called the 'kokumi' receptor because its agonists increase sweet, salty and umami tastes to induce 'koku', a Japanese word meaning the enhancement of flavor characters such as thickness, mouthfulness, and continuity. Koku is an important factor for enhancing food palatability. However, it is not well known whether other kokumi-receptors and substances exist. Here, we show that ornithine (L-ornithine but not D-ornithine) at low concentrations that do not elicit a taste of its own, enhances preferences to sweet, salty, umami, and fat taste solutions in mice. Increased preference to monosodium glutamate (MSG) was the most dominant effect. Antagonists of G-protein-coupled receptor family C group 6 subtype A (GPRC6A) abolished the additive effect of ornithine on MSG solutions. The additive effects of ornithine on taste stimuli are thought to occur in the oral cavity, and are not considered post-oral events because ornithine's effects were confirmed in a brief-exposure test. Moreover, the additive effects of ornithine and the action of the antagonist were verified in electrophysiological taste nerve responses. Immunohistochemical analysis implied that GPRC6A was expressed in subsets of type II and type III taste cells of mouse circumvallate papillae. These results are in good agreement with those reported for taste modulation involving CaSR and its agonists. The present study suggests that ornithine is a kokumi substance and GPRC6A is a newly identified kokumi receptor.

Sensory Perception of an Oral Rehydration Solution during Exercise in the Heat

Prolonged exercise in the heat elicits a number of physiological changes as glycogen stores are low and water and electrolytes are lost through sweat. However, it is unclear whether these changes provoke an increase in liking of saltiness and, therefore, palatability of an oral rehydration solution (ORS). Twenty-seven recreationally active participants (n = 13 males; n = 14 females) completed sensory analysis of an ORS, a traditional sports drink (TS), and a flavored water placebo (PL) at rest and during 60 min (3 × 20-min bouts) of cycling exercise at 70% age-predicted maximum heart rate (HR_max) at 35.3 ± 1.4 °C and 41 ± 6% relative humidity. Before and after every 20 min of exercise, drinks were rated (using 20-mL beverage samples) based on liking of sweetness, liking of saltiness, thirst-quenching ability, and overall liking on a nine-point hedonic scale. Hydration status was assessed by changes in semi-nude body mass, saliva osmolality (S_Osm), and saliva total protein concentration (S_PC). After 60 min of exercise, participants lost 1.36 ± 0.39% (mean ± SD) of body mass and there were increases in S_Osm and S_PC. At all time points, liking of sweetness, saltiness, thirst-quenching ability, and overall liking was higher for the TS and PL compared to the ORS (p < 0.05). However, the saltiness liking and thirst-quenching ability of the ORS increased after 60 min of exercise compared to before exercise (p < 0.05). There was also a change in predictors of overall liking with pre-exercise ratings mostly determined by liking of sweetness, saltiness, and thirst-quenching ability (p < 0.001), whereas only liking of saltiness predicted overall liking post-exercise (R² = 0.751; p < 0.001). There appears to be a hedonic shift during exercise in which the perception of saltiness becomes the most important predictor of overall liking. This finding supports the potential use of an ORS as a valuable means of hydration during the latter stages of prolonged and/or intense exercise in the heat.

Genetic deletion of the Tas2r143/Tas2r135/Tas2r126 cluster reveals that TAS2Rs may not mediate bitter tastant-induced bronchodilation

Bitter taste receptors (TAS2Rs) and their signaling elements are detected throughout the body, and bitter tastants induce a wide variety of biological responses in tissues and organs outside the mouth. However, the roles of TAS2Rs in these responses remain to be tested and established genetically. Here, we employed the CRISPR/Cas9 gene-editing technique to delete three bitter taste receptors-Tas2r143/Tas2r135/Tas2r126 (i.e., Tas2r triple knockout [TKO]) in mice. The fidelity and effectiveness of the Tas2r deletions were validated genetically at DNA and messenger RNA levels and functionally based on the tasting of TAS2R135 and TAS2R126 agonists. Bitter tastants are known to relax airways completely. However, TAS2R135 or TAS2R126 agonists either failed to induce relaxation of pre-contracted airways in wild-type mice and Tas2r TKO mice or relaxed them dose-dependently, but to the same extent in both types of mice. These results indicate that TAS2Rs are not required for bitter tastant-induced bronchodilation. The Tas2r TKO mice also provide a valuable model to resolve whether TAS2Rs mediate bitter tastant-induced responses in many other extraoral tissues.

Dietary Supplementation with Monosodium Glutamate Suppresses Chemotherapy-Induced Downregulation of the T1R3 Taste Receptor Subunit in Head and Neck Cancer Patients

(Background) We investigated the effect of dietary supplementation with monosodium glutamate (MSG) on chemotherapy-induced downregulation of the T1R3 taste receptor subunit expression in the tongue of patients with advanced head and neck cancer. (Methods) Patients undergoing two rounds of chemoradiotherapy were randomly allocated to a control or intervention group (dietary supplementation with MSG at 2.7 g/day during the second round of chemotherapy). The relative expression of T1R3, a subunit of both umami and sweet taste receptors, in the tongue was assessed by quantitative polymerase chain reaction analysis. Dysgeusia was assessed with a visual analog scale and daily energy intake was evaluated. (Results) T1R3 expression levels in the tongue, taste sensitivity, and daily energy intake were significantly reduced after the first round of chemotherapy compared with before treatment. Furthermore, these parameters significantly decreased after the second round of chemotherapy, but the extent of decrease was significantly attenuated in the MSG group compared with the control group. (Conclusions) MSG supplementation suppresses chemotherapy-induced dysgeusia, possibly due to the inhibition of the T1R3-containing taste receptor downregulation in the tongue, thereby increasing energy intake in patients with advanced head and neck cancer.

Combination of ozone and ultrasonic-assisted aerosolization sanitizer as a sanitizing process to disinfect fresh-cut lettuce

Reduction of sanitizer dosage and development of non-immersion disinfection methods have become major focuses of research. Here, we examined the disinfection efficacy of combining gaseous ozone (4 and 8 ppm) with aerosolized oxidizing sanitizer [sodium hypochlorite (SH, 100 and 200 ppm)] and aerosolized organic acid [acetic acid (AA, 1% and 2%) and lactic acid (LA, 1% and 2%)]. Notably, 1% AA and 4 ppm gaseous ozone were ineffective for disinfecting Salmonella Typhimurium, and treatment with 1% AA + 8 ppm ozone caused browning of lettuce leaves and stimulated increases in aerobic mesophilic count (AMC), aerobic psychrotrophic count (APC), S. Typhimurium, and Escherichia coli O157:H7. Treatment with 2% LA + 8 ppm ozone resulted in the lowest S. Typhimurium, E. coli O157:H7, Listeria monocytogenes, AMC, APC, and molds and yeasts during storage (0-7 days at 4 °C). Quality analysis indicates that LA + 8 ppm ozone and SH + 8 ppm ozone did not negatively affect L*, a*, b*, polyphenolic content, weight loss, and sensory properties; however, the levels of two individual phenolic compounds (3,4-dihydroxybenzoic acid and vanillin), responsible for phenylpropanoid synthesis, were significantly increased after treatment with 2% LA + 8 ppm ozone. These findings provided insights into the use of LA combined with gaseous ozone for application in disinfecting fresh produce.

Encapsulation of Fruit Flavor Compounds through Interaction with Polysaccharides

Production and storage, the influence of packaging materials and the presence of other ingredients in fruit products can cause changes in flavor compounds or even their loss. Due to these issues, there is a need to encapsulate flavor compounds, and polysaccharides are often used as efficient carriers. In order to achieve effective encapsulation, satisfactory retention and/or controlled release of flavor compounds, it is necessary to understand the nature of the coated and coating materials. Interactions that occur between these compounds are mostly non-covalent interactions (hydrogen bonds, hydrophobic interactions and van der Waals forces); additionally, the formation of the inclusion complexes of flavor compounds and polysaccharides can also occur. This review provides insight into studies about the encapsulation of flavor compounds, as well as basic characteristics of encapsulation such as the choice of coating material, the effect of various factors on the encapsulation efficiency and an explanation of the nature of binding.

The effects of voluntary adolescent alcohol consumption on alcohol taste reactivity in Long Evans rats

RATIONALE

The relationship between age, ethanol intake, and the hedonic value of ethanol is key to understanding the motivation to consume ethanol.

OBJECTIVE

It is uncertain whether ethanol drinking during adolescence changes ethanol's hedonic value into adulthood.

METHODS

The current study compared voluntary intermittent ethanol consumption (IAE; 2-bottle choice; 20%v/v) among adolescent and adult Long-Evans rats to examine the effects of age and IAE on taste reactivity in adulthood. For taste reactivity, orally infused fluids included water, ethanol (5, 20, and 40%v/v), and sucrose (0.01, 0.1, 1M).

RESULTS

IAE results indicate that adolescents drank more ethanol during IAE but had a lower rate of change in ethanol consumption across time than adults due to initially high adolescent drinking. During taste reactivity testing for ethanol, IAE rats had greater hedonic responding, less aversive responding, and a more positive relationship between hedonic responses and ethanol concentration than water-receiving control rats. Hedonic responses had positive, while aversive responses had negative relationships with ethanol concentration and total ethanol consumed during IAE. Adolescent+IAE rats displayed less hedonic and more aversive responses to ethanol than Adult+IAE rats. Sucrose responding was unrelated to ethanol consumption.

CONCLUSIONS

These results suggest that ethanol consumption influences the future hedonic and aversive value of ethanol in a way that makes ethanol more palatable with greater prior consumption. However, it appears that those drinking ethanol as adolescents may be more resistant to this palatability shift than those first drinking as adults, suggesting different mechanisms of vulnerability to consumption escalation for adolescents and adults.

Inhibition of Bitter Taste from Oral Tenofovir Alafenamide

Children have difficulty swallowing capsules. Yet, when presented with liquid formulations, children often reject oral medications due to their intense bitterness. Presently, effective strategies to identify methods, reagents, and tools to block bitterness remain elusive. For a specific bitter-tasting drug, identification of the responsible bitter receptors and discovery of antagonists for those receptors can provide a method to block perceived bitterness. We have identified a compound (6-methylflavone) that can block responses to an intensely bitter-tasting anti-human immunodeficiency virus (HIV) drug, tenofovir alafenamide (TAF), using a primary human taste bud epithelial cell culture as a screening platform. Specifically, TAS2R39 and TAS2R1 are the main type 2 taste receptors responding to TAF observed via heterologously expressing specific TAS2R receptors into HEK293 cells. In this assay, 6-methylflavone blocked the responses of TAS2R39 to TAF. In human sensory testing, 8 of 16 subjects showed reduction in perceived bitterness of TAF after pretreating (or "prerinsing") with 6-methylflavone and mixing 6-methylflavone with TAF. Bitterness was completely and reliably blocked in two of these subjects. These data demonstrate that a combined approach of human taste cell culture-based screening, receptor-specific assays, and human psychophysical testing can successfully discover molecules for blocking perceived bitterness of pharmaceuticals, such as the HIV therapeutic TAF. Our hope is to use bitter taste blockers to increase medical compliance with these vital medicines. SIGNIFICANCE STATEMENT: Identification of a small molecule that inhibits bitter taste from tenofovir alafenamide may increase the compliance in treating children with human immunodeficiency virus infections.

Chloroquine: Autophagy inhibitor, antimalarial, bitter taste receptor agonist in fight against COVID-19, a reality check?

The recent SARS-CoV-2 pandemic poses one of the greatest challenges to modern medicine. Therefore, identification of new therapeutic strategies seems essential either based on novel vaccines or drugs or simply repurposing existing drugs. Notably, due to their known safety profile, repurposing of existing drugs is the fastest and highly efficient approach to bring a therapeutic to a clinic for any new indication. One such drug that has been used extensively for decades is chloroquine (CQ, with its derivatives) either for malaria, lupus and rheumatoid arthritis. Accumulating body of evidence from experimental pharmacology suggests that CQ and related analogues also activate certain pathways that can potentially be exploited for therapeutic gain. For example, in the airways, this has opened an attractive avenue for developing novel bitter taste ligands as a new class of bronchodilators for asthma. While CQ and its derivatives have been proposed as a therapy in COVID-19, it remains to be seen whether it really work in the clinic? To this end, our perspective aims to provide a timely yet brief insights on the existing literature on CQ and the controversies surrounding its use in COVID-19. Further, we also highlight some of cell-based mechanism(s) that CQ and its derivatives affect in mediating variety of physiological responses in the cell. We believe, data emanating from the clinical studies and continual understanding of the fundamental mechanisms may potentially help in designing effective therapeutic strategies that meets both efficacy and safety criteria for COVID-19.

Mechanisms of DEET gustation in Drosophila

DEET is the most widely used active ingredient in insect repellents and offers protection against insect bites. We previously reported that DEET suppresses the feeding behavior of Drosophila, which is guided by gustatory receptors (GRs) in bitter-sensing gustatory receptor neurons. Here, we sought to identify new candidates using egg-laying assays. Upon screening all GR mutants, GR89a was identified as a potential DEET receptor. Gr89a mutants exhibited reduced oviposition avoidance, feeding avoidance, and electrophysiological responses compared to Gr32a, Gr33a, and Gr66a mutants. However, GR89a was found to modulate DEET avoidance, as demonstrated by genetic and RNA interference assays. Furthermore, we found that DEET ingestion severely affected larval and pupal development and survival, and therefore may act as an effective larvicide.

Sex differences in fat taste responsiveness are modulated by estradiol

Sex as a biological variable has been the focus of increasing interest. Relatively few studies have focused, however, on differences in peripheral taste function between males and females. Nonetheless, there are reports of sex-dependent differences in chemosensitivity in the gustatory system. The involvement of endogenous changes in ovarian hormones has been suggested to account for taste discrepancies. Additionally, whether sex differences exist in taste receptor expression, activation, and subsequent signaling pathways that may contribute to different taste responsiveness is not well understood. In this study, we show the presence of both the nuclear and plasma membrane forms of estrogen receptor (ER) mRNA and protein in mouse taste cells. Furthermore, we provide evidence that estrogen increases taste cell activation during the application of fatty acids, the chemical cue for fat taste, in taste receptor cells. We found that genes important for the transduction pathway of fatty acids vary between males and females and that these differences also exist across the various taste papillae. In vivo support for the effect of estrogens in taste cells was provided by comparing the fatty acid responsiveness in male, intact female, and ovariectomized (OVX) female mice with and without hormone replacement. In general, females detected fatty acids at lower concentrations, and the presence of circulating estrogens increased this apparent fat taste sensitivity. Taken together, these data indicate that increased circulating estrogens in the taste system may play a significant role in physiology and chemosensory cellular activation and, in turn, may alter taste-driven behavior.NEW & NOTEWORTHY Using molecular, cellular, and behavioral analyses, this study shows that sex differences occur in fat taste in a mouse model. Female mice are more responsive to fatty acids, leading to an overall decrease in intake and fatty acid preference. These differences are linked to sex hormones, as estradiol enhances taste cell responsiveness to fatty acids during periods of low circulating estrogen following ovariectomy and in males. Estradiol is ineffective in altering fatty acid signaling during a high-estrogen period and in ovariectomized mice on hormone replacement. Thus, taste receptor cells are a direct target for actions of estrogen, and there are multiple receptors with differing patterns of expression in taste cells.

Cucurbitacin B Suppresses Hyperglycemia Associated with a High Sugar Diet and Promotes Sleep in Drosophila melanogaster

Secondary metabolites enable plants to protect themselves from herbivorous insects. Among these, cucurbitacin B (cuc-B) is a bitter-tasting compound with promising pharmacological potential. Dietary exposure to cuc-B lowered the hemolymph glucose levels of Drosophila melanogaster fed with a high carbohydrate diet, which is homologous to high blood glucose in humans, and its effect was comparable to that of metformin, a well-known glucose-lowering drug. Furthermore, cuc-B reduced tissue sugar levels and glycogen levels, as well as triacylglycerol levels. Our results thus highlight the potential applicability of this compound to treat chronic metabolic diseases such as diabetes and obesity. Additionally, we analyzed sleep quality and taste-associative memory enhancement after cuc-B and metformin treatment. Both supplements increased nighttime bout length and metformin increased memory consolidation. Therefore, discarded shell of Cucurbitaceae could be processed into health supplements.

Cooling e-cigarette flavors and the association with e-cigarette use among a sample of high school students

INTRODUCTION

E-liquid flavor is typically presented by flavor category (e.g. menthol, mint, fruit, dessert). Cooling sensations produced by flavor additives such as menthol enhance appeal of e-cigarettes among youth, but not all e-liquids that produce cooling sensations are labeled as menthol. Sensory experiences produced by flavors may allow for a new way to capture e-cigarette flavor use. This study aims to examine use of flavors that produce cooling sensations among youth and its association with e-cigarette use behaviors.

METHODS

A 2019 survey of high school students (n = 4875) examined use of e-cigarette flavors that produced cooling sensations (cooling flavors) among past 30-day e-cigarette users. E-cigarette use behaviors (flavor use, nicotine use, frequency of use) were examined between those who did and did not use cooling flavors. A binary logistic regression was used to examine associations between vaping frequency, nicotine (vs. non-nicotine) use, and vaping cooling flavors while controlling for demographics, number of flavors vaped in the past month, and vaping age of onset.

RESULTS

51.6% (n = 473/916) of the analytic sample endorsed vaping cooling flavors. There were no demographic differences by vaping cooling flavors. Vaping cooling flavors was associated with vaping more frequently (AOR:1.04,95% CI:1.03,1.05) and vaping nicotine (AOR:2.37,95% CI:1.53,3.67).

CONCLUSION

Vaping cooling flavors was associated with greater nicotine vaping and frequency of e-cigarette use. Assessing sensory experience, such as cooling, in addition to flavor category may more fully capture e-cigarette flavor use and its impacts on youth e-cigarette use behaviors.

Identification and Comparison of Peptides from Chickpea Protein Hydrolysates Using Either Bromelain or Gastrointestinal Enzymes and Their Relationship with Markers of Type 2 Diabetes and Bitterness

The chickpea (Cicer arietinum L.) is one of the most important pulses worldwide. The objective was to identify, compare and evaluate peptides from chickpea hydrolysates produced by two enzymatic treatments. The antidiabetic potential and bitterness of the peptides and induction of bitter receptors were identified in silico. Proteins were isolated from the Kabuli variety. Peptides were produced from the proteins using a simulated digestive system (pepsin/pancreatin, 1:50 Enzyme/Protein, E/P), and these peptides were compared with those produced via bromelain hydrolysis (1:50 E/P). The protein profiles, sequences and characteristics of the peptides were evaluated. The biochemical inhibition and molecular docking of dipeptidyl peptidase-IV (DPP-IV), α-amylase and α-glucosidase were also studied. The molecular docking identified peptides from enzymatic hydrolysis as inhibitors of DPP-IV. The high hydrophobicity of the peptides indicated the potential for bitterness. There was no correlation between peptide length and DPP-IV binding. Peptides sequenced from the pepsin/pancreatin hydrolysates, PHPATSGGGL and YVDGSGTPLT, had greater affinity for the DPP-IV catalytic site than the peptides from the bromelain hydrolysates. These results are in agreement with their biochemical inhibition, when considering the inhibition of sitagliptin (54.3 µg/mL) as a standard. The bitter receptors hTAS2R38, hTAS2R5, hTAS2R7 and hTAS2R14 were stimulated by most sequences, which could be beneficial in the treatment of type 2 diabetes. Chickpea hydrolysates could be utilized as functional ingredients to be included in the diet for the prevention of diabetes.

Genetic recombination in disgust-associated bitter taste-responsive neurons of the central nucleus of amygdala in male mice

A bitter substance induces specific orofacial and somatic behavioral reactions such as gapes in mice as well as monkeys and humans. These reactions have been proposed to represent affective disgust, and therefore, understanding the neuronal basis of the reactions would pave the way to understand affective disgust. It is crucial to identify and access the specific neuronal ensembles that are activated by bitter substances, such as quinine, the intake of which induces disgust reactions. However, the method to access the quinine-activated neurons has not been fully established yet. Here, we show evidence that a targeted recombination in active populations (TRAP) method, induces genetic recombination in the quinine-activated neurons in the central nucleus of the amygdala (CeA). CeA is one of the well-known emotional centers of the brain. We found that the intraoral quinine infusion, that resulted in disgust reactions, increased both cFos-positive cells and Arc-positive cells in the CeA. By using Arc-CreER;Ai3 TRAP mice, we induced genetic recombination in the quinine-activated neurons and labelled them with fluorescent protein. We confirmed that the quinine-TRAPed fluorescently-labelled cells preferentially coexpressed Arc after quinine infusion. Our results suggest that the TRAP method can be used to access specific functional neurons in the CeA.

Effect of CO2 Preservation Treatments on the Sensory Quality of Pomegranate Juice

Due to the interest in identifying cost-effective techniques that can guarantee the microbiological, nutritional, and sensorial aspects of food products, this study investigates the effect of CO2 preservation treatment on the sensory quality of pomegranate juice at t0 and after a conservation period of four weeks at 4 °C (t28). The same initial batch of freshly squeezed non-treated (NT) juice was subjected to non-thermal preservation treatments with supercritical carbon dioxide (CO2), and with a combination of supercritical carbon dioxide and ultrasound (CO2-US). As control samples, two other juices were produced from the same NT batch: A juice stabilized with high pressure treatment (HPP) and a juice pasteurized at high temperature (HT), which represent an already established non-thermal preservation technique and the conventional thermal treatment. Projective mapping and check-all-that-apply methodologies were performed to determine the sensory qualitative differences between the juices. The volatile profile of the juices was characterized by gas chromatography-mass spectrometry. The results showed that juices treated with supercritical CO2 could be differentiated from NT, mainly by the perceived odor and volatile compound concentration, with a depletion of alcohols, esters, ketones, and terpenes and an increase in aldehydes. For example, in relation to the NT juice, limonene decreased by 95% and 90%, 1-hexanol decreased by 9% and 17%, and camphene decreased by 94% and 85% in the CO2 and CO2-US treated juices, respectively. Regarding perceived flavor, the CO2-treated juice was not clearly differentiated from NT. Changes in the volatile profile induced by storage at 4 °C led to perceivable differences in the odor quality of all juices, especially the juice treated with CO2-US, which underwent a significant depletion of all major volatile compounds during storage. The results suggest that the supercritical CO2 process conditions need to be optimized to minimize impacts on sensory quality and the volatile profile.

Prognostic factors of recovery with medication in patients with taste disorders

Objectives

We aimed to elucidate the prognostic factors of the patients with taste disorders who were treated with popular and common medication in Japan.

Materials and methods

A retrospective study on the medical charts of a total of 255 patients with taste disorders who were treated primarily with oral medication including a zinc agent.

Results

The factors below were significantly linked with poor prognosis: 1) male gender, 2) taste disorders that began 3 months before starting treatment and 3) a severe taste disorder grade at the initial visit.

Conclusions

We have concluded that the prognosis for the patients with taste disorders who were treated by popular and standard medication therapy in Japan recently was significantly linked to gender, the period of 3 months before starting the treatment and the severity of the disorder at the time of diagnosis. In addition, we recognized some limitations we should resolve in further research including a method of measuring “umami” and so on.

Clinical relevance

Better awareness of these factors should be clinically useful when we manage patients with taste disorders. Earlier treatment should be started to cure the symptoms.

Identification of two bitter components in Zanthoxylum bungeanum Maxim. and exploration of their bitter taste mechanism through receptor hTAS2R14

Bitterness is an inherent organoleptic characteristic affecting the flavor of Zanthoxylum bungeanum Maxim. In this study, the vital bitter components of Z. bungeanum were concentrated through solvent extraction, sensory analysis, silica gel chromatography, and thin-layer chromatographic techniques and subsequently identified by UPLC-Q-TOF-MS. Two components with the highest bitterness intensities (BIs), such as 7-methoxycoumarin and 8-prenylkaempferol were selected. The bitter taste perceived thresholds of 7-methoxycoumarin and 8-prenylkaempferol were 0.062 mmol/L and 0.022 mmol/L, respectively. Moreover, the correlation between the contents of the two bitter components and the BIs of Z. bungeanum were proved. The results of siRNA and flow cytometry showed that 7-methoxycoumarin and 8-prenylkaempferol could activate the bitter receptor hTAS2R14. The results concluded that 7-methoxycoumarin and 8-prenylkaempferol contribute to the bitter taste of Z. bungeanum.

Smell and taste recovery in coronavirus disease 2019 patients: a 60-day objective and prospective study

BACKGROUND

The long-term recovery rate of chemosensitive functions in coronavirus disease 2019 patients has not yet been determined.

METHOD

A multicentre prospective study on 138 coronavirus disease 2019 patients was conducted. Olfactory and gustatory functions were prospectively evaluated for 60 days.

RESULTS

Within the first 4 days of coronavirus disease 2019, 84.8 per cent of patients had chemosensitive dysfunction that gradually improved over the observation period. The most significant increase in chemosensitive scores occurred in the first 10 days for taste and between 10 and 20 days for smell. At the end of the observation period (60 days after symptom onset), 7.2 per cent of the patients still had severe dysfunctions. The risk of developing a long-lasting disorder becomes significant at 10 days for taste (odds ratio = 40.2, 95 per cent confidence interval = 2.204-733.2, p = 0.013) and 20 days for smell (odds ratio = 58.5, 95 per cent confidence interval = 3.278-1043.5, p = 0.005).

CONCLUSION

Chemosensitive disturbances persisted in 7.2 per cent of patients 60 days after clinical onset. Specific therapies should be initiated in patients with severe olfactory and gustatory disturbances 20 days after disease onset.

Cucurbitacin B Activates Bitter-Sensing Gustatory Receptor Neurons via Gustatory Receptor 33a in Drosophila melanogaster

The Gustatory system enables animals to detect toxic bitter chemicals, which is critical for insects to survive food induced toxicity. Cucurbitacin is widely present in plants such as cucumber and gourds that acts as an anti-herbivore chemical and an insecticide. Cucurbitacin has a harmful effect on insect larvae as well. Although various beneficial effects of cucurbitacin such as alleviating hyperglycemia have also been documented, it is not clear what kinds of molecular sensors are required to detect cucurbitacin in nature. Cucurbitacin B, a major bitter component of bitter melon, was applied to induce action potentials from sensilla of a mouth part of the fly, labellum. Here we identify that only Gr33a is required for activating bitter-sensing gustatory receptor neurons by cucurbitacin B among available 26 Grs, 23 Irs, 11 Trp mutants, and 26 Gr-RNAi lines. We further investigated the difference between control and Gr33a mutant by analyzing binary food choice assay. We also measured toxic effect of Cucurbitacin B over 0.01 mM range. Our findings uncover the molecular sensor of cucurbitacin B in Drosophila melanogaster. We propose that the discarded shell of Cucurbitaceae can be developed to make a new insecticide.

Flavor-specific enhancement of electronic cigarette liquid consumption and preference in mice

BACKGROUND

The use of electronic cigarettes has increased over the past decade. To determine how the abuse liability of electronic cigarette liquids (e-liquids) differs from nicotine alone, and to determine the impact of flavor, we compared nicotine-containing fruit- and tobacco-flavored e-liquids, and their nicotine-free versions, to nicotine alone in mouse models of oral consumption, reward and aversion.

METHODS

Adult male C57BL/6 J mice voluntarily consumed oral nicotine, equivalent nicotine concentrations of fruit- and tobacco-flavored e-liquid, and equivalent dilutions of the nicotine-free versions in 2-bottle choice tests. Conditioned place preference and place aversion were assessed with peripherally administered e-liquids or nicotine. Serum nicotine and cotinine levels were measured after subcutaneous injections of e-liquid or nicotine.

RESULTS

Mice showed higher consumption and preference for the fruit-flavored e-liquid compared with nicotine alone. This increase was not due to the flavor itself as consumption of the nicotine-free fruit-flavored e-liquid was not elevated until the highest concentration tested. The increased consumption and preference were not observed with the tobacco-flavored e-liquid. The conditioned place preference, place aversion and nicotine pharmacokinetics of the fruit-flavored e-liquid were not significantly different from nicotine alone.

CONCLUSIONS

Our data suggest that fruit, but not tobacco flavor, increased the oral consumption of e-liquid compared with nicotine alone. Moreover, this enhancement was not due to increased consumption of the flavor itself, altered rewarding or aversive properties after peripheral administration, or altered pharmacokinetics. This flavor-specific enhancement suggests that some flavors may lead to higher nicotine intake and increased use of e-liquids compared with nicotine alone.

Effects of Metformin and Sitagliptin Monotherapy on Expression of Intestinal and Renal Sweet Taste Receptors and Glucose Transporters in a Rat Model of Type 2 Diabetes

Disordered intestinal sweet taste receptors (STRs) are implicated in glucose homeostasis by involving in incretin secretion and glucose absorption. However, the effects of antidiabetic medications on STRs, downstream molecules, and glucose transporters expression are unknown. In our study, ZDF rats (n=24) were randomly treated by metformin (MET, 215.15 mg/kg), sitagliptin (SIT, 10.76 mg/kg), or saline for 4 weeks. Fasting blood glucose and insulin levels were measured, and HOMA-IR and QUICKI index were calculated. One week later, we detected relative mRNA expression of T1R2/T1R3, α-gustducin, TRPM5 and glucose transporters including SGLT1, SGLT2, and GLUT2 in the small intestine and kidney. We found that though both metformin and sitagliptin effectively decreased fasting blood glucose, only metformin improved HOMA-IR and QUICKI (p<0.05). MRNA levels of STRs and sweet taste molecules in duodenum and jejunum were not different among three groups, but those in ileum were dramatically upregulated after SIT (vs. MET p<0.05; vs. CON p<0.01). SGLT1 and GLUT2 in ileum were markedly increased after SIT (p<0.01). In the kidney, expression of SGLT2 and GLUT2 were downregulated in both SIT and MET group (p<0.05). In conclusion, metformin and sitagliptin exerted different effects on expression of STRs and glucose transporters in the gut and kidney. STRs, downstream molecules, and glucose transporters in distal small intestinal were sensitively increased in response to sitagliptin than metformin treatment. Renal glucose transporters were downregulated after metformin and sitagliptin treatment.

GLP-1 Analog Modulates Appetite, Taste Preference, Gut Hormones, and Regional Body Fat Stores in Adults with Obesity

PURPOSE

Obesity is associated with alterations in appetite, gastrointestinal hormone levels and excessive fat mass. We previously published a double-blind, placebo-controlled, randomized, 16-week trial on effects of once-daily glucagon-like peptide-1 (GLP-1) analog, liraglutide on weight, satiation, and gastric functions in obese volunteers. The aim of this substudy is to compare to placebo the effects of liraglutide on appetite, taste preference, regional body fat stores, and anthropometric measurements.

METHODS

Forty obese adults received standard instruction for weight management, monthly behavioral intervention utilizing motivational interviews, and 16-week treatment of once-daily liraglutide (escalated to 3 mg SQ daily). At baseline and 16 weeks, the following were measured: appetite and taste preferences rated every 30 min for 5 h after ingesting 300 mL Ensure®; maximal tolerated volume (MTV) with a nutrient drink test; fasting and postprandial bioactive GLP-1 (7-36) and peptide YY (PYY) levels; total and regional body fat with dual-energy X-ray absorptiometry, and waist and hip circumference.

RESULTS

Thirty-five participants (17 liraglutide; 18 placebo) completed the trial. Compared to placebo group, liraglutide group had significant reductions in MTV; prospective food consumption score; desire to eat something sweet, salty, savory or fatty; and an increase in perceived fullness. Postprandial plasma levels of GLP-1 decreased and PYY levels increased with liraglutide relative to baseline. Significant reductions in total body, trunk, and upper and lower body fat without reduction in lean body mass were observed.

CONCLUSION

Liraglutide 3 mg SQ modulates appetite, taste preference, gut hormones, and regional body fat stores in adults with obesity without reduction in lean body mass.

Two neuronal groups for NaCl with differential taste response properties and topographical distributions in the rat parabrachial nucleus

It is crucial for animals to discriminate between palatable (safe) and aversive (toxic) tastants. The mechanisms underlying neuronal discrimination of taste stimuli remain unclear. We examined relations between taste response properties (spike counts, response duration, and coefficient of variation [CV]) and location of taste-sensitive neurons in the pontine parabrachial nucleus (PBN). Extracellular single units' activity in the PBN of Wistar rats was recorded using multibarrel glass micropipettes under urethane anesthesia. Forty taste-sensitive neurons were classified as NaCl (N)-best (n = 15), NaCl/HCl (NH)-best (n = 14), HCl (H)-best (n = 8), and sucrose (S)-best (n = 3) neurons. The net response to NaCl (15.2 ± 2.3 spikes/s) among the N-best neurons was significantly larger than that among the NH-best (4.5 ± 0.8 spikes/s) neurons. The response duration (4.5 ± 0.2 s) of the N-best neurons to NaCl was significantly longer than that of the NH-best (2.2 ± 0.3 s) neurons. These differences in the spike counts and the response durations between the two neuronal types in the PBN were similar to that previously reported in the rostral nucleus of the solitary tract (rNST). The CVs in the N-best and the NH-best neurons were significantly smaller in the PBN than those in the rNST. Histologically, most N-best neurons (12/13, 92%) were localized to the medial region, while NH-best neurons (11/13, 85%) were primarily found within the brachium conjunctivum. These results suggest that NaCl-specific taste information is transmitted by two distinct neuronal groups (N-best and NH-best), with different taste properties and locations within rNST to PBN tractography. Future studies on the higher order nuclei for taste could reveal more palatable and aversive taste pathways.

Suppression of Oral Sweet Sensations during Consumption of Sweet Food in Humans: Effects on Gastric Emptying Rate, Glycemic Response, Appetite, Food Satisfaction and Desire for Basic Tastes

Suppression of oral sweet sensation (OSS) acutely reduces intake of sweet-tasting food due to lower liking. However, little is known about other physiological responses during both the prandial and postprandial phase. Here, we explored the effects of Gymnema sylvestre (GS)-based suppression of OSS of several types of sweet-tasting food (muffin, sweet yogurt, banana) on gastric emptying, blood glucose (BG), plasma insulin (PI), appetite indices (hunger, fullness and prospective consumption), satisfaction and desire for tastes. Fifteen healthy subjects (22 ± 3 years, 9 women) took part in the study. Subjects rinsed their mouth with either GS solution or distilled water before eating the sweet-tasting food. Subjects felt decreased sweet taste intensity and reduced taste liking associated with GS rinsing after consuming each food, compared with rinsing with distilled water (p < 0.05). Gastric emptying, BG, PI and appetite indices during and after the prandial phase did not significantly change with GS rinsing compared to rinsing with distilled water (p > 0.05). Higher desire for sweet taste as well as lower satisfaction (p < 0.05) in the postprandial phase were observed with GS rinsing. These results suggest that the suppression of OSS does not affect gastric emptying, glycemic response and appetite during and after consumption of sweet-tasting food.

Kokumi Taste Active Peptides Modulate Salt and Umami Taste

Kokumi taste substances exemplified by γ-glutamyl peptides and Maillard Peptides modulate salt and umami tastes. However, the underlying mechanism for their action has not been delineated. Here, we investigated the effects of a kokumi taste active and inactive peptide fraction (500-10,000 Da) isolated from mature (FII_m) and immature (FII_im) Ganjang, a typical Korean soy sauce, on salt and umami taste responses in humans and rodents. Only FII_m (0.1-1.0%) produced a biphasic effect in rat chorda tympani (CT) taste nerve responses to lingual stimulation with 100 mM NaCl + 5 μM benzamil, a specific epithelial Na⁺ channel blocker. Both elevated temperature (42 °C) and FII_m produced synergistic effects on the NaCl + benzamil CT response. At 0.5% FII_m produced the maximum increase in rat CT response to NaCl + benzamil, and enhanced salt taste intensity in human subjects. At 2.5% FII_m enhanced rat CT response to glutamate that was equivalent to the enhancement observed with 1 mM IMP. In human subjects, 0.3% FII_m produced enhancement of umami taste. These results suggest that FII_m modulates amiloride-insensitive salt taste and umami taste at different concentration ranges in rats and humans.

Lipopolysaccharide-Induced Inflammatory Cytokine Expression in Taste Organoids

Inflammatory cytokines are signaling molecules that regulate numerous physiological processes, from tissue homeostasis to metabolism and food intake. Expression of certain cytokines can be markedly induced in subsets of taste bud cells under acute and chronic inflammation. This may contribute to altered taste perception and preference associated with many diseases. Although the pathways of cytokine induction are well studied in immune cells, they remain poorly characterized in taste cells, in part due to the difficulties of performing biochemical analyses with a limited number of taste cells. The recently developed taste organoid model provides an opportunity to carry out these mechanistic studies in vitro. However, it was unknown whether taste organoids respond to inflammatory stimuli as do in vivo native taste buds. Here we analyze lipopolysaccharide (LPS)-induced expression and secretion of two inflammatory cytokines, tumor necrosis factor (TNF), and interleukin-6 (IL-6). We show that, similarly to native mouse taste epithelia, organoids derived from mouse circumvallate stem cells express several toll-like receptors (TLRs), including TLR4-the primary receptor for LPS. Organoids and native taste epithelia express all five genes in the nuclear factor-κb (Nfkb) family that encode the transcription factor NF-κB, a critical regulator of inflammatory responses. LPS stimulates fast induction of TNF and IL-6 with similar induction kinetics in organoids and native taste epithelia. These results show that taste epithelial cells possess necessary components for inflammatory cytokine induction and secretion and suggest that the organoid model can be a useful tool to dissect the underlying mechanisms.

Sweet Thermal Taste: Perceptual Characteristics in Water and Dependence on TAS1R2/TAS1R3

The initial objective of this study was to determine if activation of the sweet taste receptor TAS1R2/TAS1R3 is necessary for perception of sweet thermal taste (swTT). Our approach was to inhibit the receptor with the inverse agonist lactisole using a temperature-controlled flow gustometer. Because all prior studies of thermal taste (TT) used metal thermodes to heat the tongue tip, we first investigated whether it could be generated in heated water. Experiment 1 showed that sweetness could be evoked when deionized water was heated from 20 to 35 °C, and testing with static temperatures between 20 and 35 °C demonstrated the importance of heating from a cool temperature. As in previous studies, thermal sweetness was reported by only a subset of participants, and replicate measurements found variability in reports of sweetness across trials and between sessions. Experiment 2 then showed that exposure to 8 mM lactisole blocked perception of swTT. Confirmation of the involvement of TAS1R2/TAS1R3 led to an investigation of possible sensory and cognitive interactions between thermal and chemical sweetness. Using sucrose as a sweet stimulus and quinine as a nonsweet control, we found that dynamic heating capable of producing thermal sweetness did not increase the sweetness of sucrose compared with static heating at 35 °C. However, swTT was disrupted if trials containing sucrose (but not quinine) were interspersed among heating-only trials. These findings provide new information relevant to understanding the perceptual processes and receptor mechanisms of swTT, as well as the heat sensitivity of sweet taste in general.

Therapeutic potential and challenges of bitter taste receptors on lung cells

Airway smooth muscle (ASM) hyperresponsiveness and airway remodeling are pathological drivers of disease progression and mortality in asthma. Importantly, approximately 50% of affected individuals are unable to reliably manage disease symptoms using the current standard of care. Recently, T2Rs have been identified as a novel class of G protein-coupled receptors expressed in the airway that on activation can induce ASM relaxation and reduction in airway tone. Further, agonists of T2Rs may also remedy airway remodeling, which has been difficult to manage with currently available medications. In this review, we will discuss the recent developments in T2R biology and their role in cellular physiology (particularly ASM) and expand on the therapeutic potential of T2R agonists in treatment of asthma.

Gastrointestinal taste receptors: could tastants become drugs?

PURPOSE OF REVIEW

Numerous studies have pointed to profound nongustatory roles of tastants and the corresponding taste receptors expressed in the alimentary canal in the modulation of digestive and metabolic functions. Already in early reports, the intriguing possibility to use tastants as drug-like effectors for the treatment of metabolic diseases was raised. With this review, focusing on the most recent literature, we intend to question how close we meanwhile came to the initial promise - the use of tastants as medicines.

RECENT FINDINGS

Although the enormous complexity and experimental variability of studies investigating the effects of tastants on physiological functions still has not revealed a common fundament from which subsequent therapeutic measures could be designed, more and more evidence is mounting on an involvement of taste receptors and taste signaling molecules in the maintenance and fine regulation of gastrointestinal functions and immunity.

SUMMARY

Although the initial goal - using tastants to treat metabolic disorders - has, by far, not been reached, numerous promising findings suggest that dietary interventions could be devised to support conventional therapies in the future.

A Fatty Acid Mouth Rinse Decreases Self-Reported Hunger and Increases Self-Reported Fullness in Healthy Australian Adults: A Randomized Cross-Over Trial

Fatty acid (FA) chemoreception in the oral cavity, known as fat taste, may trigger a satiety response that is homologous to FA chemoreception in the gastrointestinal tract. In addition, individuals with an impaired fat taste sensitivity are more likely to have an impaired satiety response. This study aimed to assess the effect of an FA mouth rinse on self-reported appetite, and to determine if the effect is modified by fat taste sensitivity. Thirty-one participants (age, 32.0 ± 8.4 y; body mass index (BMI), 26.1 ± 8.1 kg/m²) were studied on four separate days to evaluate the effect of a 20 mM oleic acid (OA) mouth rinse (in duplicate) compared to a control (in duplicate) on self-reported appetite by using a visual analogue scale (VAS) every 30 min for three hours following a standardized low-fat breakfast. The area under the curve ratings for fullness were greater (p = 0.003), and those for hunger were lower (p = 0.002) following the OA rinse compared to the control. The effect of the OA rinse was greater in individuals who were hypersensitive to fat taste compared to moderately sensitive and hyposensitive individuals for fullness (p < 0.010) and hunger (p < 0.010) ratings. In summary, an OA mouth rinse decreases self-reported hunger and increases self-reported fullness, particularly in those who are more sensitive to fat taste. FA receptors in the oral cavity may be potential targets to regulate appetite.

Associations between Cadmium Exposure and Taste and Smell Dysfunction: Results from the National Health and Nutrition Examination Survey (NHANES), 2011-2014

Background: Cadmium is a ubiquitous environmental pollutant and has been associated with many adverse health outcomes. However, little is known about the effect of cadmium exposure on taste and smell dysfunction. Methods: We used the National Health and Nutrition Examination Survey (NHANES) 2011–2014 to investigate the associations between blood cadmium and taste and smell dysfunction among 5038 adults aged 40–80 years old. Taste and smell dysfunction were defined by questionnaires, examinations, or both criteria. Results: In survey weighted logistic regression models adjusting for age, gender, race/ethnicity, income-to-poverty ratio (IPR), and education, individuals with a blood cadmium level in the highest tertiles had significantly higher odds of having perceived smell dysfunction (odds ratio (OR) = 1.41, 95% confidence interval (CI): 1.08, 1.84), perceived taste dysfunction (OR = 1.48, 95% CI: 1.16, 1.89), and taste dysfunction defined by both self-reported and objectively measured data (OR = 1.46, 95% CI: 1.03, 2.07). After further adjusting for body mass index (BMI), cigarette smoking, and alcohol drinking, consistent results were observed for perceived taste dysfunction (OR = 1.49, 95% CI: 1.10, 2.00), and no significant associations were found between cadmium exposure and other outcomes. Conclusions: Our findings suggest that cadmium exposure is associated with perceived taste dysfunction.

Intragastric administration of the bitter tastant quinine lowers the glycemic response to a nutrient drink without slowing gastric emptying in healthy men

The rate of gastric emptying and the release of gastrointestinal (GI) hormones are major determinants of postprandial blood-glucose concentrations and energy intake. Preclinical studies suggest that activation of GI bitter-taste receptors potently stimulates GI hormones, including glucagon-like peptide-1 (GLP-1), and thus may reduce postprandial glucose and energy intake. We evaluated the effects of intragastric quinine on the glycemic response to, and the gastric emptying of, a mixed-nutrient drink and the effects on subsequent energy intake in healthy men. The study consisted of 2 parts: part A included 15 lean men, and part B included 12 lean men (aged 26 ± 2 yr). In each part, participants received, on 3 separate occasions, in double-blind, randomized fashion, intragastric quinine (275 or 600 mg) or control, 30 min before a mixed-nutrient drink (part A) or before a buffet meal (part B). In part A, plasma glucose, insulin, glucagon, and GLP-1 concentrations were measured at baseline, after quinine alone, and for 2 h following the drink. Gastric emptying of the drink was also measured. In part B, energy intake at the buffet meal was quantified. Quinine in 600 mg (Q600) and 275 mg (Q275) doses alone stimulated insulin modestly (P < 0.05). After the drink, Q600 and Q275 reduced plasma glucose and stimulated insulin (P < 0.05), Q275 stimulated GLP-1 (P < 0.05), and Q600 tended to stimulate GLP-1 (P = 0.066) and glucagon (P = 0.073) compared with control. Quinine did not affect gastric emptying of the drink or energy intake. In conclusion, in healthy men, intragastric quinine reduces postprandial blood glucose and stimulates insulin and GLP-1 but does not slow gastric emptying or reduce energy intake under our experimental conditions.

Artificial taste avoidance memory induced by coactivation of NMDA and β-adrenergic receptors in the amygdala

The association between a taste and gastric malaise allows animals to avoid the ingestion of potentially toxic food. This association has been termed conditioned taste aversion (CTA) and relies on the activity of key brain structures such as the amygdala and the insular cortex. The establishment of this gustatory-avoidance memory is related to glutamatergic and noradrenergic activity within the amygdala during two crucial events: gastric malaise (unconditioned stimulus, US) and the post-acquisition spontaneous activity related to the association of both stimuli. To understand the functional implications of these neurochemical changes on avoidance memory formation, we assessed the effects of pharmacological stimulation of β-adrenergic and glutamatergic NMDA receptors through the administration of a mixture of L-homocysteic acid and isoproterenol into the amygdala after saccharin exposure on specific times to emulate the US and post-acquisition local signals that would be occurring naturally under CTA training. Our results show that activation of NMDA and β-adrenergic receptors generated a long-term avoidance response to saccharin, like a naturally induced rejection with LiCl. Moreover, the behavioral outcome was accompanied by changes in glutamate, norepinephrine and dopamine levels within the insular cortex, analogous to those displayed during memory retrieval of taste aversion memory. Therefore, we suggest that taste avoidance memory can be induced artificially through the emulation of specific amygdalar neurochemical signals, promoting changes in the amygdala-insular cortex circuit enabling memory establishment.

Appeal of JUUL among adolescents

INTRODUCTION

JUUL is a closed-system e-cigarette that uses disposable pods with high concentrations of nicotine. JUUL use among youth arose exponentially since 2015, thus, it is essential to understand youths' reasons for liking/disliking JUUL to inform the regulation of the product.

METHODS

A cross-sectional survey was conducted in 4 high schools in Connecticut in 2018 (N = 3170). The survey assessed JUUL use in the past month and reasons for liking/disliking JUUL, which included pharmacological effects (e.g., subjective nicotine and/or flavor effects), product characteristics (e.g., flavors, nicotine, shape), peer influence (e.g., friends' use), comparisons to other e-cigarettes (e.g., lower harm), and concealability (e.g., hide from authority).

RESULTS

30.2% (N = 956) were past-month users who used a JUUL on an average of 13.6 days (SD = 11.7; 25% reported daily use). The top reasons for liking JUUL were: "it gives me a buzz" (52%), "I like the flavors" (43%), and "my friends use it" (36%). The top reasons for disliking JUUL were: "the pods are expensive" (57%), "nicotine is too high" (20%), and "it gives me a headache" (18%). Regression models indicated that liking JUUL because of the buzz, ability to help concentrate, nicotine level, and ease of hiding it from teachers were associated with more days of use in the past month, while peer influence was negatively associated. Furthermore, disliking the high cost of pods was associated with more frequent use.

CONCLUSIONS

Comprehensive policies that regulate device characteristics that appeal to youth (e.g., nicotine level, flavors) are needed to prevent JUUL use among youth.

Co-occurring Gastrointestinal Symptoms Are Associated With Taste Changes in Oncology Patients Receiving Chemotherapy

CONTEXT

Over 80% of patients with cancer report taste changes. Despite the high prevalence of this symptom and its negative effects on health, few studies have assessed its association with other gastrointestinal (GI) symptoms.

OBJECTIVES

Determine the occurrence, frequency, severity, and distress of patient-reported "change in the way food tastes" (CFT) and identify phenotypic and GI symptoms characteristics associated with its occurrence.

METHODS

Patients receiving chemotherapy for breast, GI, gynecological, or lung cancer completed demographic and symptom questionnaires prior to their second or third cycle of chemotherapy. CFT was assessed using the Memorial Symptom Assessment Scale. Differences in demographic, clinical, and GI symptom characteristics were evaluated using parametric and nonparametric tests.

RESULTS

Of the 1329 patients, 49.4% reported experiencing CFT in the week prior to their second or third cycle of chemotherapy. In the univariate analysis, patients who reported CFT had fewer years of education; were more likely to be black or Hispanic, mixed race, or other; and had a lower annual household income. A higher percentage of patients with CFT reported the occurrence of 13 GI symptoms (e.g., constipation, diarrhea, abdominal cramps, feeling bloated). In a multivariable logistic regression analysis, compared with patients with breast cancer, patients with lung cancer (odds ratio = 0.55; P = 0.004) had a decrease in the odds of being in the CFT group. Patients who received a neurokinin-1 receptor antagonist and two other antiemetics were at an increased odds of being in the CFT group (odds ratio = 2.51; P = 0.001). Eight of the 13 GI symptoms evaluated were associated with an increased odds of being in the CFT group.

CONCLUSIONS

This study provides new evidence on the frequency, severity, and distress of CFT in oncology patients undergoing chemotherapy. These findings suggest that CFT is an important problem that warrants ongoing assessments and nutritional interventions.

Bioavailability testing of a newly developed clindamycin oral suspension in a pediatric porcine model

Background: Clindamycin's bitter taste and odor is known to affect treatment adherence in children. Recently, a formulation of clindamycin HCl complexed with ion exchange resin IRP 69 was shown to mask the bitter taste. Because of the potential benefit of this formulation for children, a pilot study using a porcine model was conducted to evaluate its relative bioavailability. Methods: A randomized two-way crossover study design using six (n = 6) healthy male piglets 10-12 kg was used to evaluate the absorption profiles and pharmacokinetic parameters of clindamycin from the resinate complex formulation (Test) compared to a commercialized reference suspension. A dose of 15 mg/kg was administered orally by gastric gavage to each piglet followed by repeated blood sampling over 12 h. A wash-out period of 48 h occurred between treatments. Plasma concentration vs. time data was analyzed by non-compartmental analysis. Results: The mean relative bioavailability of clindamycin from the resinate formulation was 78.8%. A two-tailed, paired Student t test yielded a p < 0.05 for AUC∞ and Tmax parameters. A two one-sided test (TOST) suggested a difference in AUC∞ and Cmax for the Test formulation compared to the reference formulation according to the FDA's criteria for bioequivalence. Conclusion: The bioavailability of clindamycin from this novel oral formulation supports continued evaluation of the drug in humans for potential pediatric applications.

Bitter taste signaling mediated by Tas2r144 is down-regulated by 17β-estradiol and progesterone in the rat choroid plexus

The blood-cerebrospinal fluid barrier is constituted by choroid plexus epithelial cells (CPEC) that regulate molecular trafficking between the blood and the cerebrospinal fluid. We hypothesize that taste receptors expressed in CPEC monitor the composition of these body fluids in a sex hormone dependent way. Thus, we compared the expression of taste related genes in the choroid plexus of sham and ovariectomized female rats, and then studied the effect of 17β-estradiol and progesterone in their expression and function. We found that the bitter receptors Tas2r109, Tas2r144, and the taste-related genes Plcb2 and Trpm5 were down-regulated by ovarian hormones in vivo and ex vivo with functional implications. Knocking-down Tas2r144 with a specific siRNA in a CPEC line (Z310) effectively reduced the Ca²⁺ response to the bitter compound denatonium benzoate, in a similar manner to female sex hormones alone, suggesting that female sex hormones downregulated the responses of CPEC to chemical stimuli by reducing Tas2r144.

Glycated Beef Protein Hydrolysates as Sources of Bitter Taste Modifiers

Being averse to bitter taste is a common phenomenon for humans and other animals, which requires the pharmaceutical and food industries to source compounds that can block bitterness intensity and increase consumer acceptability. In this work, beef protein alcalase hydrolysates (BPAH) and chymotrypsin hydrolysates (BPCH) were reacted with glucose to initiate Maillard reactions that led to the formation of glycated or advanced glycation end products (AGEs), BPAH-AGEs and BPCH-AGEs, respectively. The degree of glycation was higher for the BPAH-AGEs (47-55%) than the BPCH-AGEs (30-38%). Analysis by an electronic tongue instrument showed that BPAH-AGEs and BPCH-AGEs had bitterness scores that were significantly (p < 0.05) less than quinine. The addition of BPAH-AGEs or BPCH-AGEs to quinine led to significant (p < 0.05) reductions (up to 38%) in bitterness intensity of quinine. The use of 3% hydrolysate to react with glucose yielded glycated peptides with a stronger ability to reduce quinine bitterness than when 1% was used. Calcium release from HEK293T cells stably expressing the T2R4 human bitter taste receptor was significantly (p < 0.05) attenuated by BPAH-AGEs (up to 96%) and BPCH-AGEs (up to 92%) when compared to the BPAH (62%) and BPCH (3%) or quinine (0%). We concluded that BPAH-AGEs and BPCH-AGEs may be used as bitter taste blockers to formulate better tasting foods.

Low intake of digestible carbohydrates ameliorates duodenal absorption of carbohydrates in mice with glucose metabolism disorders induced by artificial sweeteners

BACKGROUND

Long-term artificial sweetener consumption has been reported to induce glucose intolerance, and the intestinal microbiota seems as an important target. While the impacts of artificial sweeteners on energy balance remain controversial, this work aimed to evaluate the protective effects in mice of a low digestible carbohydrate (LDC) diet on plasma glucose, plasma fasting insulin, sweet taste receptors, glucose transporters, and absorption of carbohydrates, together with consumption of acesulfame potassium (AK) or saccharin (SAC).

RESULTS

Artificial sweetener was administered to mice for 12 weeks to induce glucose metabolism disorders; mice were treated with an LDC diet for the final 6 weeks. The experimental groups were treated with an LDC diet that had the same energy as the normal-diet group. Prolonged administration of artificial sweeteners led to metabolic dysfunction, characterized by significantly increased plasma glucose, insulin resistance, sweet taste receptors, glucose transporters, and absorption of carbohydrates. Treatment with an LDC diet positively modulated these altered parameters, suggesting overall beneficial effects of an LDC diet on detrimental changes associated with artificial sweeteners.

CONCLUSIONS

Reducing digestible carbohydrates in the diet can significantly reduce the absorption of carbohydrates and improve glucose metabolism disorders caused by dietary factors. These effects may be due to the fact that reducing the amount of digestible carbohydrates in the feed can reduce the number of intestinal sweet receptors induced by exposure to artificial sweeteners. © 2019 Society of Chemical Industry.

Taste Receptors in Upper Airway Innate Immunity

Taste receptors, first identified on the tongue, are best known for their role in guiding our dietary preferences. The expression of taste receptors for umami, sweet, and bitter have been demonstrated in tissues outside of the oral cavity, including in the airway, brain, gastrointestinal tract, and reproductive organs. The extra-oral taste receptor chemosensory pathways and the endogenous taste receptor ligands are generally unknown, but there is increasing data suggesting that taste receptors are involved in regulating some aspects of innate immunity, and may potentially control the composition of the nasal microbiome in healthy individuals or patients with upper respiratory diseases like chronic rhinosinusitis (CRS). For this reason, taste receptors may serve as potential therapeutic targets, providing alternatives to conventional antibiotics. This review focuses on the physiology of sweet (T1R) and bitter (T2R) taste receptors in the airway and their activation by secreted bacterial products. There is particular focus on T2R38 in sinonasal ciliated cells, as well as the sweet and bitter receptors found on specialized sinonasal solitary chemosensory cells. Additionally, this review explores the impact of genetic variations in these receptors on the differential susceptibility of patients to upper airway infections, such as CRS.

Postprandial metabolic effects of fructose and glucose in type 1 diabetes patients: a pilot randomized crossover clinical trial

OBJECTIVE

To test the influence of oral fructose and glucose dose-response solutions in blood glucose (BG), glucagon, triglycerides, uricaemia, and malondialdehyde in postprandial states in type 1 diabetes mellitus (T1DM) patients.

SUBJECTS AND METHODS

The study had a simple-blind, randomized, two-way crossover design in which T1DM patients were selected to receive fructose and glucose solutions (75g of sugars dissolved in 200 mL of mineral-water) in two separate study days, with 2-7 weeks washout period. In each day, blood samples were drawn after 8h fasting and at 180 min postprandial to obtain glucose, glucagon, triglycerides, uric acid, lactate, and malondialdehyde levels.

RESULTS

Sixteen T1DM patients (seven men) were evaluated, with a mean age of 25.19 ± 8.8 years, a mean duration of disease of 14.88 ± 4.73 years, and glycated hemoglobin of 8.13 ± 1.84%. Fructose resulted in lower postprandial BG levels than glucose (4.4 ± 5.5 mmol/L; and 12.9 ± 4.1 mmol/L, respectively; p < 0.01). Uric acid levels increased after fructose (26.1 ± 49.9 µmol/L; p < 0.01) and reduced after glucose (-13.6 ± 9.5 µmol/L; p < 0.01). The malondialdehyde increased after fructose (1.4 ± 1.6 µmol/L; p < 0.01) and did not change after glucose solution (-0.2 ± 1.6 µmol/L; p = 0.40). Other variables did not change.

CONCLUSIONS

Fructose and glucose had similar sweetness, flavor and aftertaste characteristics and did not change triglycerides, lactate or glucagon levels. Although fructose resulted in lower postprandial BG than glucose, it increased uric acid and malondialdehyde levels in T1DM patients. Therefore it should be used with caution. ClinicalTrials.gov registration: NCT01713023.

Peracetic acid reduces Campylobacter spp. on turkey skin: Effects of a spray treatment on microbial load, sensory and meat quality during storage

Handling and consumption of Campylobacter-contaminated poultry meat is the most common cause of human campylobacteriosis. While many studies deal with interventions to reduce Campylobacter spp. on chicken carcasses, studies on other poultry species are rare. In the present study, a spray treatment with peracetic acid (PAA) on turkey carcasses was evaluated. For this, parts of breast fillets with skin and Campylobacter (C.) jejuni DSM 4688 (108 cfu/ml) inoculated drumsticks were sprayed for 30 s with PAA (1200 ppm) or water as control solution. Samples were packaged under modified atmosphere and stored at 4°C until analysis on day 1, 6 and 12. The breast fillets were used for determination of the total viable count, sensory and meat quality examination as well as myoglobin content and biogenic amines. The drumsticks were used for C. jejuni counts. PAA had a significant effect in reducing total viable counts on all days by up to 1.2 log10 compared to the untreated control. Treatment with water alone showed no effect. C. jejuni counts were significantly reduced by PAA (0.9-1.3 log10), while water achieved a 0.5 log10 reduction on C. jejuni counts on day 1. No differences in sensory, pH, electrical conductivity and myoglobin content could be found. The skin of the PAA treated fillets had lower redness values than the water control on day 1, whereas on day 12 parts of the water treated muscles were lighter than the untreated control. A lower putrescine content of the water sprayed fillets in comparison to the control sample on day 12 was the only significant difference concerning the biogenic amines. Results from this study indicate that a spray treatment with 1200 ppm PAA would be a useful measure to lower the Campylobacter spp. counts on turkey carcasses without having a negative influence on product quality.

Bitter-Induced Salivary Proteins Increase Detection Threshold of Quinine, But Not Sucrose

Exposures to dietary tannic acid (TA, 3%) and quinine (0.375%) upregulate partially overlapping sets of salivary proteins which are concurrent with changes in taste-driven behaviors, such as rate of feeding and brief access licking to quinine. In addition, the presence of salivary proteins reduces chorda tympani responding to quinine. Together these data suggest that salivary proteins play a role in bitter taste. We hypothesized that salivary proteins altered orosensory feedback to bitter by decreasing sensitivity to the stimulus. To that end, we used diet exposure to alter salivary proteins, then assessed an animal's ability to detect quinine, using a 2-response operant task. Rats were asked to discriminate descending concentrations of quinine from water in a modified forced-choice paradigm, before and after exposure to diets that alter salivary protein expression in a similar way (0.375% quinine or 3% TA), or 1 of 2 control diets. Control animals received either a bitter diet that does not upregulate salivary proteins (4% sucrose octaacetate), or a nonbitter diet. The rats exposed to salivary protein-inducing diets significantly decreased their performance (had higher detection thresholds) after diet exposure, whereas rats in the control conditions did not alter performance after diet exposure. A fifth group of animals were trained to detect sucrose before and after they were maintained on the 3% TA diet. There was no significant difference in performance, suggesting that these shifts in threshold are stimulus specific rather than task specific. Taken together, these results suggest that salivary proteins reduce sensitivity to quinine.

Cyclophosphamide and the taste system: Effects of dose fractionation and amifostine on taste cell renewal

Chemotherapy often causes side effects that include disturbances in taste functions. Cyclophosphamide (CYP) is a chemotherapy drug that, after a single dose, elevates murine taste thresholds at times related to drug-induced losses of taste sensory cells and disruptions of proliferating cells that renew taste sensory cells. Pretreatment with amifostine can protect the taste system from many of these effects. This study compared the effects of a single dose (75 mg/kg) of CYP with effects generated by fractionated dosing of CYP (5 doses of 15 mg/kg), a dosing approach often used during chemotherapy, on the taste system of mice using immunohistochemistry. Dose fractionation prolonged the suppressive effects of CYP on cell proliferation responsible for renewal of taste sensory cells. Fractionation also reduced the total number of cells and the proportion of Type II cells within taste buds. The post-injection time of these losses coincided with the life span of Type I and II taste cells combined with lack of replacement cells. Fractionated dosing also decreased Type III cells more than a single dose, but loss of these cells may be due to factors related to the general health and/or cell renewal of taste buds rather than the life span of Type III cells. In general, pretreatment with amifostine appeared to protect taste cell renewal and the population of cells within taste buds from the cytotoxic effects of CYP with few observable adverse effects due to repeated administration. These findings may have important implications for patients undergoing chemotherapy.