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NCT Number: NCT05359887

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

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.

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This study is active but is not currently recruiting participants.

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Key information

Conditions

Obesity Body Weight Nutrition Disorders Nutritional and Metabolic Diseases Overnutrition Overweight Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

MCL

Leeuwarden, Netherlands

Who can participate

Healthy volunteers accepted: No

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

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.

Treatment and study plan

standardized liquid mixed meal Nutridrink®

Other

Administration of food in controlled situation

Primary outcomes

  1. Change in [11C]-raclopride binding potential in the brain's reward system between study groups before and after a food challenge.

    Time frame: -50 minutes (before start of PET scanning), 0 minutes (during PET break, before mixed meal), 30 minutes (after second phase of PET-scanning)

    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

Secondary outcomes

  1. The correlation between [11C]-raclopride binding potential in the brain's reward system and of questionnaires and diaries

    Time frame: Pre-intervention

    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.

  2. The correlation between [11C]-raclopride binding potential in the brain's reward system and of gut hormones.

    Time frame: -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

    The relation between fasting or fed (gut) hormone concentrations and dopamine D2 receptor availability in the reward system.

Sponsors and collaborators

Lead sponsor

University Medical Center Groningen

Other

Registry information

Acronym: ObesiPET

Important dates

Study start
2022
Primary completion
2026
Study completion
2026
First posted
May 4, 2022
Registry last updated
Apr 29, 2026

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

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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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