The Molecular Basis for a Broad Range of Phenotypes Related to hTAS2R38

NCT01399944 | Completed

• 3 other identifiers: 813211F32DC011975-01A1R01DC011287-01
• Study Type: observational
• Target: 70
• Locations: 1 country
• Sites: 1

Brief Summary

This single-site, within-subject, experimental study is designed to test the hypothesis that individuals express taste receptors differently and have different sensitivities to bitter taste samples, which results from uneven expression. Subjects will include 100 racially and ethnically diverse, healthy adults. All subjects will provide saliva samples for genetic analysis and undergo taste testing with common psychophysical stimuli. From the pool of 100 subjects, 36 subjects from the common heterozygous group (PAV/AVI) and two from each homozygous group (AVI/AVI, nontaster and PAV/PAV, taster) will be invited to return for two additional sessions. During both sessions the investigators will 1) measure bitterness thresholds for PROP, a common psychophysical stimulus; 2) measure bitterness perception of several vegetables; 3) obtain a saliva sample and 4) collect taste papillae. The investigators will then isolate DNA and RNA from the taste papillae and isolate DNA from saliva to evaluate molecular differences over time and between individuals and how it relates to taste psychophysics. All psychophysical and cellular measurements will be done during both sessions so that the investigators can determine how much variation is observed over a one-week time period in both cellular phenotype and psychophysical phenotype.

Conditions

Healthy

Keywords

bitter taste; psychophysics; genetics; epigenetics; bitterness sensitivity

Outcome Measures

Primary Outcomes (4)

• Bitter taste thresholds

  Thresholds for propylthiouracil (PROP) will be measured using modified Harris-Kalmus recognition thresholds.

  2 days of testing (2 hours each)

• Taste intensity and hedonic ratings of vegetables

  Subjects will rate the intensity of five basic taste qualities (bitter, salt, sweet, sour, umami) and the liking of PROP, urea, quinine, caffeine, denatonium solutions and pureed vegetables using the general labelled magnitude scale (gLMS)

  3 days of testing (1-2 hours each)

• TAS2R Genotype

  Genotype of several TAS2Rs will be determined from DNA extracted from a saliva sample.

  1 day of testing (1-1.5 hours)

• mRNA expression levels

  Expression of taste and related genes will be determined from mRNA extracted from human taste tissue obtained via tongue biopsy.

  2 days of testing (2 hours each)

Secondary Outcomes (2)

• Dietary habits

  2 days (2 hours each)

• biometrics

  1 day (1-1.5 hours)

Eligibility Criteria

• Age: 18 Years - 40 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)
• Sampling Method: Non-Probability Sample

Study Population

Adults of all races and both genders (N=100) will be involved in the proposed research. Typically, our population of subjects is approximately 45% African American, 45% Caucasian, 6% Hispanic, and 4% Asian. This increased representation of under-represented minorities in our subject populations is reflective of the greater Philadelphia region and has been achieved, in part, through our outreach efforts advertising in local newspapers throughout the city.

Sponsors & Collaborators

• Monell Chemical Senses Center: lead
• National Institute on Deafness and Other Communication Disorders (NIDCD): collaborator

Study Sites (1)

Monell Chemical Senses Center

Philadelphia, Pennsylvania, 19104, United States

Location

Related Publications (1)

• Lipchock SV, Mennella JA, Spielman AI, Reed DR. Human bitter perception correlates with bitter receptor messenger RNA expression in taste cells. Am J Clin Nutr. 2013 Oct;98(4):1136-43. doi: 10.3945/ajcn.113.066688. Epub 2013 Sep 11.

  PMID: 24025627 DERIVED

Biospecimen

Retention: SAMPLES WITH DNA

Saliva and taste tissue will be collected from individuals enrolled in the study.

Study Officials

• Julie A. Mennella, PhD

  Monell Chemical Senses Center

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: observational
• Observational Model: CASE ONLY
• Time Perspective: CROSS SECTIONAL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Member

Study Record Dates

• First Submitted: July 20, 2011
• First Posted: July 22, 2011
• Study Start: July 1, 2011
• Primary Completion: June 1, 2013
• Study Completion: June 1, 2013
• Last Updated: December 18, 2017

Record last verified: 2017-12

Locations

US (1)