Gustin Gene Polymorphism and 6-n-propylthiouracil (PROP) Taste

Study Overview
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Brief Summary
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The investigators evaluate the possible association of PROP taste with gustin gene polymorphism rs2274333 (A/G), salivary zinc ion concentration and BMI. In addition, it has also been evaluated PROP taste sensitivity by recording monophasic potentials from the tongue.

Detailed Description
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The investigators evaluate the possible association of PROP taste with gustin gene polymorphism rs2274333 (A/G), salivary zinc ion concentration and BMI. Furthermore, we apply direct measures of the gustatory system activation following stimulation with PROP, obtained by electrophysiological recordings from the tongue of subjects classified for taster status, genotyped for the specific receptor gene (TAS2R38), and in which papilla density was determined.

Official Title
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Sensitivity to 6-n-propylthiouracil (PROP) Association With Gustin (CA6) Gene Polymorphism, Salivary Zinc and BMI in Humans

Conditions
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Dysgeusia

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: no variation of body weight > 5 kg over the last 3 mo BMI within 20-25 Age between 20-30 Exclusion Criteria: gustatory impairment following a prescribed diet or using medications that might interfere with taste perception food allergies smokers

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 30 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| PROP taste sensitivity<br>PROP Sensitive and non sensitive individuals are defined as Tasters and Non-tasters, respectively. Taster are further divided in Super-taster who perceived PROP as extremely bitter and Medium tasters who perceived PROP as moderately bitter. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Association Between Gustin Gene Polymorphism and PROP Sensitivity | We examine associations between PROP status and the polymorphism rs2274333 (A/G) of the gene that codify for the salivary protein, gustin/CA6, Which has been suggested as a trophic factor that promotes growth and development of taste buds by acting on taste bud stem cells. The intensity of taste perception evoked by PROP and NaCl solutions was estimated to evaluate PROP taster status and molecular analysis of the gustin gene polymorphism was performed in individuals classified by PROP status using PCR techniques. | 7 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Association Between PROP Sensitivity and Saliva Zinc Ion Concentration | Since the enzymatic function of gustin (CA6) depends upon the presence of Zn at its active site we measured the salivary zinc ion concentration in subjects classified as super-taster, medium taster and non-taster.The salivary Zn2+ concentration was measured with a QuantiChromTM zinc Assay kit (Gentaur, Brussels, Belgium) where the color intensity is directly proportional to the Zn2+ concentration in the sample. | 7 months | 
| Association Between PROP Sensitivity and BMI | Since individual ability to taste PROP may be correlated with BMI, we determined BMI (kg/m^2) in subjects classified as super-taster, medium taster and non-taster.Weight (kg) and height (m) were recorded for each subject. | 7 months | 
| Electrophysiological Recordings From the Tongue for the Objective Evaluation of Individual Variations of 6-n-propylthiouracil (PROP) Sensitivity | electrophysiological recordings from the tongue of 43 subjects classified for their taste sensitivity to 6-n- propyltiouracil (PROP) and genotyped for the specific receptor gene, TAS2R38. Density of fungiform papillae was also determined in each subject. The biopotentials were recorded by means of differential electrophysiological derivations between two silver electrodes, one in contact with the ventral surface of the tongue and one in perfect adhesion with the dorsal surface. | 1 year | 
| Association Between PROP Sensitivity and Fungiform Papilla Density | 43 subjects were classified for their taste sensitivity to 6-n- propyltiouracil (PROP) and density of fungiform papillae was determined in each subject. | 6 months | 
| Taste Perception of Sweet, Sour, Salty, Bitter and Umami and Changes Due to L-Arginine Supplementation, as a Functin of Genetic Ability to Taste PROP. | Taste perception was assessed by testing the ability to recognize, and the responsiveness to, representative solutions of the five taste qualities, also when supplemented with L-Arg, in subjects classified as PROP-tasters. | 8 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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BMI, PROP taste sensitivity, Gustin (CAVI) polymorphism, Salivary zinc, Electrophysiological recording from the tongue