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

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

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.

Study Overview

• Status: Completed
• Conditions: Dysgeusia

Detailed Description

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.

• Study Type: Observational
• Enrollment (Actual): 170

Contacts and Locations

Study Locations

• Italy
  • Ca
    • Cagliari, Ca, Italy, 09124
      • Sezione di Farmacologia Clinica del Dipartimento di Neuroscienze, San Giovanni di Dio Azienda Ospedaliero Universitaria di Cagliari

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 20 years to 30 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Probability Sample

Study Population

Seventy-five non-smoking volunteers (28 men and 47 women) were recruited for the study. Participants between 20-30 years were eligible for the study. Thresholds for the 4 basic tastes were evaluated in all subjects in order to rule out any gustatory impairment. The volunteers showed no variation of body weight > 5 kg over the last 3 mo. They were not following a prescribed diet or using medications that might interfere with taste perception; none had food allergies. They were assessed for cognitive eating behaviours using the Three-Factor Eating Questionnaire

Description

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

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Prospective

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
PROP taste sensitivity; 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?

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

Collaborators and Investigators

• Sponsor: University of Cagliari
• Investigators: Principal Investigator: Iole Tomassini Barbarossa, PhD, Dip. Scienze Biomediche Sezione di Fisiologia Università di Cagliari

Publications and helpful links

General Publications

• Padiglia A, Zonza A, Atzori E, Chillotti C, Calo C, Tepper BJ, Barbarossa IT. Sensitivity to 6-n-propylthiouracil is associated with gustin (carbonic anhydrase VI) gene polymorphism, salivary zinc, and body mass index in humans. Am J Clin Nutr. 2010 Sep;92(3):539-45. doi: 10.3945/ajcn.2010.29418. Epub 2010 Jul 14.

Study record dates

Study Major Dates

• Study Start: October 1, 2009
• Primary Completion (Actual): December 1, 2009
• Study Completion (Actual): June 1, 2016

Study Registration Dates

• First Submitted: April 1, 2010
• First Submitted That Met QC Criteria: April 1, 2010
• First Posted (Estimate): April 2, 2010

Study Record Updates

• Last Update Posted (Actual): December 21, 2018
• Last Update Submitted That Met QC Criteria: December 20, 2018
• Last Verified: December 1, 2018

More Information

Terms related to this study

• Keywords: BMI; PROP taste sensitivity; Gustin (CAVI) polymorphism; Salivary zinc; Electrophysiological recording from the tongue
• Additional Relevant MeSH Terms: Nervous System Diseases; Neurologic Manifestations; Sensation Disorders; Taste Disorders; Dysgeusia
• Other Study ID Numbers: UNICADBSITB-1

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Undecided
• IPD Plan Description: Data of this study are available from the principal investigator of this study upon request