ObesityNCT03168009
Brown Fat Activity and Bariatric Surgery
A study testing Bariatric Surgery in people with Obesity, run by Medical University of Vienna at 1 site in Austria.
Trial summary
The mechanisms of bariatric surgery-induced weight loss go beyond reductions in calorie intake and may involve several other pathways. Recently, brown adipose tissue (BAT) has been added as another potential player. Activation of BAT results in enhanced energy expenditure and promotes weight loss. Read more about this study
- Who is it for?
- Ages 20 to 50 years
- Conditions the study is for
- Obesity
- What is being tested?
- Bariatric Surgery
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 40 participants
- Where
- 1 siteAustria
- Study dates
- 24 May 2017to 31 Dec 2021
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 20 to 50 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- Age 20 - 50 years
- Body mass index (BMI) 35 - 55kg/m2
Who cannot join
- Endocrine disease (except hyperlipidemia and substituted hypothyroidism or type 2 diabetes with fasting glucose concentrations <120mg/dl), kidney disease, inflammatory bowel disease, autoimmune or rheumatologic diseases that require immunosuppressive treatment, active oncologic disease, heart failure.
- Medication for any of the above mentioned conditions.
- Antibiotic treatment in the past three months
- Pregnancy
Trial locations and contacts
1 site in 1 country.
About this study
Official title: The Role of Alternatively Activated Brown Fat in Bariatric Surgery-mediated Metabolic Improvements
The mechanisms of bariatric surgery-induced weight loss go beyond reductions in calorie intake and may involve several other pathways. Recently, brown adipose tissue (BAT) has been added as another potential player. Activation of BAT results in enhanced energy expenditure and promotes weight loss. Here, the investigators will study the effects of bariatric surgery on BAT function by PET/CT studies and molecular analyses of adipose biopsies. The investigators will explore different pathways that may affect BAT activation in this patient population.
- Conditions
- Obesity
- Being tested
- Bariatric Surgery
- Keywords
- BAT, Bariatric Surgery, Energy Metabolism
- Medical subject headings
- Obesity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Bariatric SurgeryProcedure or surgery
Patients will undergo bariatric surgery as routinely scheduled. The type of bariatric procedure will be suggested by the surgeon based on clinical considerations.
| Study group | Role | What they receive |
|---|---|---|
| Bariatric Surgery | Experimental | Patients will undergo either Omega Loop Gastric Bypass or Sleeve Gastrectomy. The decision which type of surgery will be performed, will by made by the surgeon and the patient based on clinical considerations and the patient's wishes. Receives: Procedure: Bariatric Surgery |
What is being measured
The primary outcome is the main question the study is designed to answer.
Changes in BAT activity after bariatric surgery
The primary outcome of this study is to determine whether Omega Loop Gastric Bypass and Sleeve Gastrectomy result in increased BAT activity
Measured: 4 years
Secondary outcomes (2)
Bariatric surgery-induced changes in gut microbiota, bile acid composition and other circulating factors
Any pre-versus postsurgical changes of the gut microbiota or bile acid composition or other circulating factors will be evaluated.
Measured: 4 years
Association between changes in BAT activity, transcriptional BAT markers and alterations in the gut microbiota profile or bile acid composition
Linear regression analyses will be performed to determine any association between BAT activity or molecular signature and changes in the gut microbiota or bile acids
Measured: 4 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted30 May 2017
- Study start24 May 2017
- Primary completion31 Dec 2021
- Study completion31 Dec 2021
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for ObesityStudies of the same condition, open and under way.
- More trials run by Medical University of ViennaThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 40 participants (actual)
Sponsor and investigators
- Lead sponsor
- Medical University of Vienna
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Dr. Florian Kiefer, Medical University of Vienna
- Investigators
- Florian Kiefer, MD,PHD, Principal investigator, Medical University of Vienna
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03168009
- Sponsor's protocol ID
- 1071/2017
- Status last verified
- Apr 2022
- First submitted
- 23 May 2017
- Last updated
- 12 Apr 2022
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Publications
Kulterer OC, Herz CT, Pils D, Wollenweber T, Fritzer-Szekeres M, Kautzky-Willer A, Calabretta R, Hagn G, Hacker M, Gerner C, Haug AR, Kiefer FW. Active Brown Adipose Tissue Is Associated With Reduced Arterial Inflammation and Less Atherogenic Circulating Factors in Individuals With Obesity. Arterioscler Thromb Vasc Biol. 2026 Jul;46(7):e324200. doi: 10.1161/ATVBAHA.125.324200. Epub 2026 Apr 30.
PubMed 42059078Herz CT, Kulterer OC, Prager M, Marculescu R, Prager G, Kautzky-Willer A, Hacker M, Trajanoski S, Kofeler HC, Galle B, Haug AR, Berry D, Kiefer FW. Bariatric surgery promotes recruitment of brown fat linked to alterations in the gut microbiota. Eur J Endocrinol. 2025 Apr 30;192(5):603-611. doi: 10.1093/ejendo/lvaf081.
PubMed 40366070
Study at a glance
From the registry record, last updated by the sponsor on 12 Apr 2022. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Role of Alternatively Activated Brown Fat in Bariatric Surgery-mediated Metabolic Improvements
- ClinicalTrials.gov ID
- NCT03168009
- Acronym / sponsor ID
- 1071/2017
- Conditions
- Obesity
- Keywords
- BAT, Bariatric Surgery, Energy Metabolism
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 40 participants (actual)
- Lead sponsor
- Medical University of ViennaUniversity, hospital or other
- Study start
- 24 May 2017 (actual)
- Primary completion
- 31 Dec 2021 (actual)
- Study completion
- 31 Dec 2021 (actual)
- First posted
- 30 May 2017 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The mechanisms of bariatric surgery-induced weight loss go beyond reductions in calorie intake and may involve several other pathways. Recently, brown adipose tissue (BAT) has been added as another potential player. Activation of BAT results in enhanced energy expenditure and promotes weight loss. Here, the investigators will study the effects of bariatric surgery on BAT function by PET/CT studies and molecular analyses of adipose biopsies. The investigators will explore different pathways that may affect BAT activation in this patient population.
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Bariatric Surgery | Experimental | Procedure: Bariatric SurgeryPatients will undergo either Omega Loop Gastric Bypass or Sleeve Gastrectomy. The decision which type of surgery will be performed, will by made by the surgeon and the patient based on clinical considerations and the patient's wishes. |
Who may qualify
- Ages
- 20 to 50 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (2 listed)
- Age 20 - 50 years
- Body mass index (BMI) 35 - 55kg/m2
Key exclusion criteria (4 listed)
- Endocrine disease (except hyperlipidemia and substituted hypothyroidism or type 2 diabetes with fasting glucose concentrations <120mg/dl), kidney disease, inflammatory bowel disease, autoimmune or rheumatologic diseases that require immunosuppressive treatment, active oncologic disease, heart failure.
- Medication for any of the above mentioned conditions.
- Antibiotic treatment in the past three months
- Pregnancy
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Bariatric SurgeryPatients will undergo bariatric surgery as routinely scheduled. The type of bariatric procedure will be suggested by the surgeon based on clinical considerations. | Procedure or surgery | Bariatric Surgery |
Primary outcome
Changes in BAT activity after bariatric surgery
Time frame: 4 years
The primary outcome of this study is to determine whether Omega Loop Gastric Bypass and Sleeve Gastrectomy result in increased BAT activity
2 secondary outcomes
Bariatric surgery-induced changes in gut microbiota, bile acid composition and other circulating factors
Time frame: 4 years
Association between changes in BAT activity, transcriptional BAT markers and alterations in the gut microbiota profile or bile acid composition
Time frame: 4 years
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 12 Apr 2022.
- Derived from this study: PubMed 42059078Kulterer OC, Herz CT, Pils D, Wollenweber T, Fritzer-Szekeres M, Kautzky-Willer A, Calabretta R, Hagn G, Hacker M, Gerner C, Haug AR, Kiefer FW. Active Brown Adipose Tissue Is Associated With Reduced Arterial Inflammation and Less Atherogenic Circulating Factors in Individuals With Obesity. Arterioscler Thromb Vasc Biol. 2026 Jul;46(7):e324200. doi: 10.1161/ATVBAHA.125.324200. Epub 2026 Apr 30.
- Derived from this study: PubMed 40366070Herz CT, Kulterer OC, Prager M, Marculescu R, Prager G, Kautzky-Willer A, Hacker M, Trajanoski S, Kofeler HC, Galle B, Haug AR, Berry D, Kiefer FW. Bariatric surgery promotes recruitment of brown fat linked to alterations in the gut microbiota. Eur J Endocrinol. 2025 Apr 30;192(5):603-611. doi: 10.1093/ejendo/lvaf081.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Florian Kiefer, MD,PHD principal investigator
Medical University of Vienna
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Bariatric Surgery in people with Obesity, run by Medical University of Vienna at 1 site in Austria.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 12 Apr 2022. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Austria. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Changes in BAT activity after bariatric surgery (time frame: 4 years). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT03168009, which also lists 2 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 12 Apr 2022; AzTrials last refreshed its copy on 28 Oct 2026.