PET-study on the Role of the Reward System in Weight Loss After Bariatric Surgery (ObesiPET)

Bariatric surgery (BS) is currently the most effective treatment in severe obesity. However, a considerable percentage of patients undergoing BS fail to lose sufficient weight or regain weight after initial weight loss during long-term follow-up, which may be attributed to personality traits and pathological eating behaviour. Previous positron emission tomography (PET) studies have shown reduced dopamine D2 receptor availability in obese patients and upregulation of this availability following successful BS in the brain's reward system. Dopamine D2 receptor availability in patients with unsuccessful BS has not been investigated to date.

Study Overview

• Status: Active, not recruiting
• Conditions: Obesity
• Intervention / Treatment: Other: standardized liquid mixed meal Nutridrink®

• Study Type: Interventional
• Enrollment (Estimated): 30
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Netherlands
  • Leeuwarden, Netherlands
    • MCL

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Bariatric surgery 24-36 months prior to the study
• Adult (over 18y old)
• Mentally capable to understand the consequences of the procedure and make his or her own choice without coercion
• Able to undergo PET and MRI, according to the investigator's assessment
• Native speaking
• Able to participate in follow-up
• Written informed consent

Exclusion Criteria:

• Presence of a DSM-IV axis 1 disorder
• The use of drugs that bind to dopamine D2/3 receptors, including various classes of antipsychotics and antidepressants
• History of stroke, brain tumor, Parkinson's Disease or dementia
• History of head trauma with loss of consciousness
• Alcohol or substance abuse in the last 6 months
• Alcohol consumption 24h prior to PET scanning
• Smoking or other forms of nicotine intake 12 hours prior to PET scanning
• Use of anorectic drugs in the last 6 months
• Current pregnancy
• Medication for Diabetes Mellitus
• Claustrophobia
• The presence of implanted metal objects of the type which may concentrate radiofrequency fields or cause tissue damage from twisting in a magnetic field (such as certain implanted devices, shrapnel, ocular metal shavings)
• Patients with a bodyweight > 200kg will be excluded to ensure the maximum load of the camera bed of the PET-scanner (227 kg) is not exceeded.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Unsuccessful BS (Total Weight Loss (TWL) < 20%); Fifteen who had unsuccessful BS (Total Weight Loss (TWL) < 20%)	Other: standardized liquid mixed meal Nutridrink®; Administration of food in controlled situation
Experimental: Successful BS (TWL > 25%).; Fifteen who had successful BS (TWL > 25%).	Other: standardized liquid mixed meal Nutridrink®; Administration of food in controlled situation

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in [11C]-raclopride binding potential in the brain's reward system between study groups before and after a food challenge.	Pre- and post-eating changes in dopamine D2 receptor availability as indexed by the [11C]-raclopride binding potential in the brain's reward system between subjects who underwent successful vs unsuccessful bariatric surgery	-50 minutes (before start of PET scanning), 0 minutes (during PET break, before mixed meal), 30 minutes (after second phase of PET-scanning)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The correlation between [11C]-raclopride binding potential in the brain's reward system and of questionnaires and diaries	The correlation between questionnaires on eating habits (EDE-Q, REO, YFAS) and quality of life (OBESI-Q) in patients who had successful vs unsuccessful BS and [11C]-raclopride binding potential.	Pre-intervention
The correlation between [11C]-raclopride binding potential in the brain's reward system and of gut hormones.	The relation between fasting or fed (gut) hormone concentrations and dopamine D2 receptor availability in the reward system.	-50 minutes (before start of PET scanning), 0 minutes (during PET break, before mixed meal), 30 minutes (after second phase of PET-scanning), 60 - 90 - 120 minutes

Collaborators and Investigators

• Sponsor: University Medical Center Groningen

Study record dates

Study Major Dates

• Study Start (Actual): December 1, 2022
• Primary Completion (Estimated): December 31, 2026
• Study Completion (Estimated): December 31, 2026

Study Registration Dates

• First Submitted: April 12, 2022
• First Submitted That Met QC Criteria: April 28, 2022
• First Posted (Actual): May 4, 2022

Study Record Updates

• Last Update Posted (Actual): April 29, 2026
• Last Update Submitted That Met QC Criteria: April 28, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Obesity; Reward system; PET-scan; [11C]-Raclopride
• Additional Relevant MeSH Terms: Nutrition Disorders; Overnutrition; Body Weight; Overweight; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Obesity
• Other Study ID Numbers: UMCG202100632

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No