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Completed

NCT Number: NCT02381483

Vitamin A in Brown Fat Activity

Vitamin A metabolites (retinoids) have shown to activate brown fat function in preclinical studies, however the role of retinoids in human brown fat physiology and energy metabolism remains elusive. This study aims to identify a possible association between retinoid metabolism, brown fat activity, and energy expenditure in lean and obese subjects by using FDG-PET-CT, PET-MR Scans and indirect calorimetry. Additionally we will analyze the genetic profile of white and brown neck fat biopsies at room temperature and cold conditions in a subset of the study participants. More detailed molecular studies (involving other potential browning markers) will also be performed in adipocytes derived from human SVC.

The optimal duration of cold exposure will be determined in a pilot study. Therefore subjects will be repeatedly exposed to cold and circulating retinoid levels and other plasma parameters will be measured at various time points.

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Key information

Conditions

Brown Adipose Tissue

Age range

20 year–45 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Medical University of Vienna

Vienna, 1090, Austria

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age 20 - 45 years.
  • Body mass index (BMI) 18.5 - 24.9 kg/m2 (lean) or 30.0 - 38.0 kg/m2 (obese)

Exclusion criteria

  • Endocrine (except hyperlipidemia), cardiovascular (except hypertension), liver, kidney, inflammatory bowel, rheumatic, oncologic disease or any other chronic condition.
  • Medication for any of the above mentioned conditions.
  • Pregnancy
  • Metallic implants that are not MRI compatible

Treatment and study plan

Cold exposure

Other

Primary outcomes

  1. Correlation between retinol/retinol-binding protein concentrations and cold-induced brown fat acitivity

    Time frame: 6 years

    A possible association between serum retinol and retinol-binding protein concentrations and cold-induced brown fat activity in lean and obese subjects, respectively, will be analyzed.

Secondary outcomes

  1. Analyses of potential BAT or browning markers in humans

    Time frame: 6 years

  2. Association between BAT activity and energy expenditure

    Time frame: 6 years

  3. Identification of new factors related to brown fat function

    Time frame: 6 years

    This is a very exploratory aim that involves a number of molecular tests. Therefore no single outcome measure can be defined here. Briefly, we will perform mRNA and miRNA analyses from BAT biopsies and plasma before and after cold exposure to identify new factors related to BAT function. Potential candidates will be tested in loss- or gain-of-function models in isolated human and/or murine adipocytes. In addition, the thermogenic effects of commercially available peptides, hormones, lipids, or steroid acids, will be tested in primary adipocytes.

Sponsors and collaborators

Lead sponsor

Medical University of Vienna

Other

Registry information

Official study title

The Role of Vitamin A in Brown Fat Activity and Energy Metabolism

Important dates

Study start
2014
Primary completion
2018
Study completion
2018
First posted
Mar 6, 2015
Registry last updated
Aug 20, 2018

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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