Nicotinamide Adenine Dinucleotide (NAD+) Metabolism in Human Brown Adipose Tissue

Inclusion criteria

• Willingness to provide informed consent to participate in the BATNAD study
• Must be able to read and speak English/Finnish/Swedish well enough to completely understand the instructions and provide informed consent
• Age 30-55 (sedentary lifestyle)
• BMI = 18-25 kg/m2 (normal-weight subjects)
• BMI ≥ 28 kg/m2 and waist circumference more than 100 cm in men and more than 90 cm in women (subjects with obesity)

Exclusion criteria

• Inability to have PET/CT (claustrophobia, metal implants, recent tattoo including metal components, weight > 200 kg)
• Pregnancy and pregnancy related conditions (postpartum/lactation during the last 12 months, or planning to become pregnant soon)
• Major alterations in the menstrual cycle (e.g., amenorrhea)
• Use of nicotine based products
• Hypo- or hyper- thyroidism (medical history, TSH, T3 or T4 levels out of the normal range)
• Diabetes mellitus (fasting Hb1Ac >6.5% or fasting glycaemia> 7.0 mmol/)
• Abnormal oral glucose tolerance test (2h OGTT > 11.1 mmol/L)
• Hypertension (blood pressure > 160/100 mmHg)
• Abnormal cardiovascular status (arrhythmia and/or long QTc in ECG, abnormal cardiac murmur, previous history of cardiovascular disease)
• Abnormal coagulopathy (e.g., clotting abnormality)
• Malignancies
• Immunological, autoimmune and primary/secondary immunodeficiency disorders (including or not any active treatment)
• Virus or bacterial infection (both asymptomatic and symptomatic picture) within the 45 days prior to the study start
• Vaccination within the 45 days prior to the study start
• Episode of fever or major surgery, burns and traumas within the month prior to the study start
• Chronic infections requiring chronic antibiotic or anti-viral treatment
• Whole blood donation in the last 3 months (>400 mL of blood) or plans for blood donation during the entire protocol period
• Weight change (intentional or not) over the last 6-months more than 5% of body weight, or plan to lose weight during the study
• Allergy to lidocaine or epinephrine, or other local anaesthetics
• Previous participation to studies where PET or CT method is used
• Use of any medication that, in the opinion of local clinician/researcher, would negatively impact or mitigate full participation and completion, or could influence the study results. This especially applies to the use of β or α adrenergic receptors agonists/antagonists (e.g., β-blockers).
• Any other cardiovascular, pulmonary, orthopaedic, neurologic, psychiatric or other conditions that, in the opinion of the local clinician/researcher, would preclude participation and successful completion of the protocol, or that would negatively impact or mitigate participation in and completion of the protocol