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| ID | Type | Description | Link |
|---|---|---|---|
| 24/SS/0094 | Other Identifier | Health Research Authority (HRA) |
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This clinical trial explores how repeated short-term cold exposure impacts the molecular and physiological function of brown adipose tissue (BAT), a thermogenic organ associated with improved cardiometabolic health. While intermittent cold exposure has been shown to increase BAT activity and mass, as measured by fluorodeoxyglucose (18F-FDG) uptake on positron emission tomography/computed tomography (PET/CT) scans, the molecular adaptations within BAT and other thermogenic tissues including skeletal muscle and white adipose tissue (WAT) remain poorly understood.
Healthy adults aged 18 to 40 years (6 males and 6 females) will participate in a 10-day cold acclimation protocol (2 hours per day using water-perfused cooling blankets). The primary objective is to determine how cold exposure alters cellular heterogeneity and gene expression in BAT, WAT, and skeletal muscle.
Participants will undergo baseline assessments, including measurements of energy expenditure, core and skin temperature, muscle activity, and blood sampling, each performed in both warm and cold conditions. These assessments will be followed by dynamic total-body PET/CT imaging during cold exposure and tissue biopsies from BAT, subcutaneous WAT, and skeletal muscle. These procedures will be repeated after the cold acclimation protocol to evaluate physiological and molecular changes. Additional outcomes include changes in energy expenditure, cold tolerance, and immune cell responses induced by cold exposure.
Twelve healthy adults aged 18-40 years old (6 female, 6 male) will:
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Healthy normal weight subjects | Experimental |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Cooling | Other | Participants will undergo cold exposure during the baseline and final visits (2.5 hours each visit), as well as throughout the 10-day cold acclimation period (2 hours per day). This will be achieved using water-perfused blankets set to individualized temperatures, selected to elicit comparable physiological responses across participants. |
| Measure | Description | Time Frame |
|---|---|---|
| Tissue transcriptional changes derived from cold exposure | We will be analysing and comparing gene expression from nuclei extracted from BAT, WAT and skeletal muscle before and after cold the 10-day cold acclimation protocol. | 1 year |
| Measure | Description | Time Frame |
|---|---|---|
| Changes in brown adipose tissue activity/mass before and after cold acclimation protocol | BAT activity/mass will be measured using the glucose analogue 18-FDG radiotracer combine with PET/CT. | year after |
| Energy expenditure |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Role | Phone | Extension | |
|---|---|---|---|---|
| MarĂa Paula Huertas Caycedo | Contact | 01312429196 | m.p.huertas-caycedo@sms.ed.ac.uk |
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| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Royal Infirmary of Edinburgh | Recruiting | Edinburgh | United Kingdom |
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| ID | Term |
|---|---|
| D064590 | Cool-Down Exercise |
| D001706 | Biopsy |
| D002153 | Calorimetry, Indirect |
| ID | Term |
|---|---|
| D000096063 | Post-Exercise Recovery Techniques |
| D026741 | Physical Therapy Modalities |
| D013812 | Therapeutics |
| D012046 | Rehabilitation |
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| Biopsies | Procedure | Under local anesthesia, biopsies will be obtained from the following sites:
These biopsies will be performed both before and after the 10-day cold acclimation protocol. |
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| Injection of 18F-FDG | Radiation | Intravenous injection of 18F-FDG will be performed after 2 hours of cold exposure. This will be followed by a 30min dynamic total PET/CT scan while cold exposed using water-perfused blankets. These procedures will take place before and after the 10 day-cold acclimation protocol. |
|
| Indirect calorimetry | Other | Participants will rest quietly while oxygen consumption and carbon dioxide production are continuously recorded using a indirect calorimeter. These data will be used to calculate energy expenditure and respiratory exchange ratio. This procedure will take place before and after the 10 day-cold acclimation protocol. |
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| Electromyogram | Other | Skin surface electrodes will be placed on major skeletal muscles to measure shivering and muscle activity during both warm and cold conditions. This procedure will take place before and after the 10 day-cold acclimation protocol. |
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| Core and skin temperature monitoring | Other | Participants will ingest an electronic capsule that wirelessly and continuously monitors core body temperature. This procedure will be conducted before and after the 10-day cold acclimation protocol. Additionally, wireless temperature sensors will placed at multiple standardized sites on the body to measure skin temperature. This procedure will be performed before, during, and after the 10-day cold acclimation protocol. |
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Energy expenditure measured with indirect calorimetry before and after cold acclimation protocol to evaluated any changes in response to intermittent cold exposure.
| year after |
| Skin and core temperature | Measurement of skin and core temperature before and after the cold acclimation protocol | year after |
| Immune cell levels | Analyse the percentage of immune cell populations before and after cold acclimation | year after |
| D015444 | Exercise |
| D009043 | Motor Activity |
| D009068 | Movement |
| D009142 | Musculoskeletal Physiological Phenomena |
| D055687 | Musculoskeletal and Neural Physiological Phenomena |
| D003581 | Cytodiagnosis |
| D003584 | Cytological Techniques |
| D019411 | Clinical Laboratory Techniques |
| D019937 | Diagnostic Techniques and Procedures |
| D003933 | Diagnosis |
| D013048 | Specimen Handling |
| D003949 | Diagnostic Techniques, Surgical |
| D013514 | Surgical Procedures, Operative |
| D008919 | Investigative Techniques |
| D002151 | Calorimetry |
| D002623 | Chemistry Techniques, Analytical |