Clinical trial NCT02941172: CB1 Receptors in Human Brown Adipose Tissue
Official title: Cannabinoid CB1 Receptors in Human Brown Adipose Tissue
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Obesity
Keywords: Brown adipose tissue
Cannabinoid receptor
PET imaging
Metabolism
Lead sponsor: Turku University Hospital
Sponsor class: OTHER_GOV
First posted: 2016-10-21
Enrollment: 18
Sex: MALE
Minimum age (years): 18
Maximum age (years): 60
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: NON_RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: BASIC_SCIENCE

Brief summary: This study investigates cannabinoid CB1 receptors in human brown adipose tissue (BAT) and other tissues using positron emission tomography (PET) imaging. Subjects will be scanned in room temperature conditions and during controlled cold exposure, and the density of CB1 receptors in BAT and other tissues will be quantified. The investigators hypothesize, that cannabinoid signaling is increased in cold conditions, when BAT is metabolically active.

Understanding the mechanisms of BAT activation and the role of endocannabinoids in humans is important and beneficial in fighting against the epidemic of obesity and diabetes.

Detailed description: Endocannabinoids have an important role in regulating energy balance and metabolism. Cannabinoid 1 receptors (CB1) are found in several tissues such as brown adipose tissue (BAT). Endocannabinoids and CB1 receptors participate in the control of lipid and glucose metabolism, and blockage of CB1 receptors has been found to improve metabolic factors linked to obesity and cardiovascular disease, making CB1 antagonists potential drugs against obesity and diabetes.

In this study the investigators use a PET radiotracer \[18F\]FMPEP-d2, which binds to CB1 receptors in vivo, to quantify the CB1 receptor density in BAT, white adipose tissue, muscle and the brain. This study is done once in warm conditions and once during controlled cold exposure. To verify whether the subject has metabolically active BAT, an additional PET scan with the radiotracer \[18F\]FDG is performed.

Eligibility criteria: Inclusion Criteria:

* Healthy volunteer
* Group 1: BMI 20-26 kg/m2, Group2: BMI 27-40 kg/m2

Exclusion Criteria:

* BMI \< 20 kg/m2or BMI \> 40 kg/m2
* Any chronic disease that could affect the study outcome, including medicated type 2 diabetes
* Mental disorder or poor compliance
* Eating disorder or excessive use of alcohol, tobacco smoking or drug use
* Past dose of radiation
* Presence of any ferromagnetic objects that would make MR imaging contraindicated
* Any other condition that in the opinion of the investigator could create a hazard to the subject safety, endanger the study procedures or interfere with the interpretation of study results

Primary outcomes:
measure: CB1 density of brown adipose tissue acquired with PET
timeFrame: within one study day
Secondary outcomes:
measure: Glucose uptake of brown adipose tissue acquired with PET
timeFrame: within one study day
Other outcomes:
Locations:
city: Turku
country: Finland
facility: Turku PET Centre (Turku University Hospital)
Study officials:
affiliation: Turku PET Centre (Turku University Hospital)
name: Pirjo Nuutila, M.D., Ph.D.
role: PRINCIPAL_INVESTIGATOR
References:
citation: Lahesmaa M, Eriksson O, Gnad T, Oikonen V, Bucci M, Hirvonen J, Koskensalo K, Teuho J, Niemi T, Taittonen M, Lahdenpohja S, U Din M, Haaparanta-Solin M, Pfeifer A, Virtanen KA, Nuutila P. Cannabinoid Type 1 Receptors Are Upregulated During Acute Activation of Brown Adipose Tissue. Diabetes. 2018 Jul;67(7):1226-1236. doi: 10.2337/db17-1366. Epub 2018 Apr 12.