Vitamin A in Brown Fat Activity

Not Applicable

Completed

• Conditions: Brown Adipose Tissue
• Interventions: Other: Cold exposure

• Registration Number: NCT02381483
• Lead Sponsor: Medical University of Vienna

Brief Summary

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.

Detailed Description

Not available

Study Timeline

• Study Start: 2014-02
• Study First Submitted: 2015-02-14
• Study First Submitted QC: 2015-03-05
• Study First Posted: 2015-03-06
• Primary Completion: 2018-04-15
• Study Completion: 2018-04-15
• Status Verified: 2018-08
• Last Update Submitted: 2018-08-16
• Last Update Posted: 2018-08-20

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 66

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)

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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

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Lean	Cold exposure	Cold exposure
Obese	Cold exposure	Cold exposure

Primary Outcome Measures

Name	Time	Method
Correlation between retinol/retinol-binding protein concentrations and cold-induced brown fat acitivity	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 Outcome Measures

Name	Time	Method
Analyses of potential BAT or browning markers in humans	6 years
Identification of new factors related to brown fat function	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.
Association between BAT activity and energy expenditure	6 years

Trial Locations

Locations (1)

Medical University of Vienna; 🇦🇹 Vienna, Austria