The Effect of Brown Adipose Tissue Activation on Insulin Sensitivity in Humans

Obesity Clinical Trial

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT01791114
• Other study ID #: 11-193
• Status: Completed
• Phase: N/A
• Start date: January 2012
• Est. completion date: December 30, 2018

Study information

• Verified date: January 2019
• Source: Rutgers, The State University of New Jersey
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

Recent findings document the presence of active brown adipose tissue (BAT) in humans. Cold exposure via adrenergic stimulation activates BAT, which combusts significant amounts of blood glucose and free fatty acid (FFA) to produce heat. Animal studies suggest that BAT activation improves insulin sensitivity. However, the effect of cold-induced BAT activation on insulin sensitivity and glucose kinetics in humans remains unknown. The investigators' central hypothesis is that cold-induced BAT activation increases whole body insulin sensitivity in humans via augmented plasma glucose and FFA clearance. The specific aims of this study are to define the effects of prolonged (8h) cold exposure BAT activation on: insulin sensitivity (Aim 1); lipolysis and plasma glucose and FFA kinetics (Aim 2); on thermoregulation (Aim 3). Moreover, the investigators plan to investigate for alternative ways, which can activate BAT including cold water ingestion, a single meal ingestion, and a single bout of moderate intensity exercise (Aim 4). For the cold exposure study, subjects will complete 3 trials: a) 8hrs of cold exposure at their individually determined shivering threshold; b) 8hrs of cold exposure at their individually determined shivering threshold plus propranolol; c) 8hrs in thermoneutral conditions (26 - 28°C). For the rest of the arms of subjects will complete two trials: cold or tepid water ingestion, a single meal ingestion or no food ingestion, and a single bout of moderate intensity exercise or no exercise.To study the above aims, the investigators will use positron emission tomography - computed tomography, hyperinsulinemic euglycemic clamp, infusion of stable isotopes, and tissue biopsies. The findings will illuminate the role of BAT on plasma substrate regulation and insulin sensitivity and may aid in the development of lifestyle recommendations and pharmacotherapy for the prevention and treatment of diabetes and insulin resistance.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 39
• Est. completion date: December 30, 2018
• Est. primary completion date: December 30, 2018
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years to 75 Years

Eligibility

Inclusion Criteria:

• men or women

• 18-75 years old

• BMI 20-40 kg/m2

Exclusion Criteria:

• taking diabetes medications

• liver/renal/endocrine/heart disease

• obstructive disease of the gastrointestinal tract

• impaired gag reflex or swallowing disorder

• history of GI surgery or fenilization of esophagus

• GI hypomotility disorder

• cancer

• thyroid or hormone replacement treatment

• beta-blockers

• anabolic or corticosteroids the last 6 mo

• pregnant/lactating women

• individuals that are likely to need PET/CT in the near future for medical reasons

• bleeding disorders/ anemia

• positive hepatitis or HIV screening

• weight less than 36 kg

• pacemaker or other implanted electromedical device

• alcohol and drug abuse

• tobacco use

• impaired cognition

• asthma

• chronic obstructive pulmonary disease (COPD) or other reactive airway diseases

Related Conditions & MeSH terms

• Hypersensitivity
• Insulin Resistance
• Insulin Sensitivity
• Obesity

Intervention

Other:
• Cold exposure
For the cold exposure trial, the subjects will follow an individualized cold exposure protocol maximize the elicited non-shivering thermogenesis. Subjects will be wearing liquid conditioned garments (Polar Products Inc, Stow, OH). The temperature will initially be set at 18°C, then decreased at 1 degree celsius intervals thought the air- conditioned temperature control bath until subjects report shivering. Electromyography (EMG; Delsys, Bagnoli 8, Boston, MA) will be performed continuously to verify shivering muscle activity. Upon shivering, the temperature will be increased by 1degree Celsius intervals until shivering resides. Subjects' core temperature will be measured at 10-second intervals with the use of a telemetric pill (Core Temp Inc., Palmetto, FL).
• Cold exposure plus propranolol
For the cold exposure plus propanol trial, temperature will be titrated as previously described. The non-selective beta-adrenergic antagonist propranolol (0.5mg/kg and up to 40) will be given orally before the beginning of the study and again after 4-6 hours. In case participant's heart rate after propranolol administration decreases below 50 beats per min or systolic blood pressure below 90 mmHg second dose of propranolol will not be administered. Heart rate and blood pressure will be monitored continuously throughout the study. Propranolol doses up to 80 mg have been shown to significantly reduce fludeoxyglucose (FDG) uptake in brown fat in clinical patients.
• Thermoneutral Conditions
Subjects will be exposed to thermoneutral conditions (26 - 28°C)
• Cold water consumption
Subjects will be asked to consume cold water (4 °C,10 ml/ kg body weight within 10 minutes)
• Tepid water consumption
Subjects will be asked to consume cold water (36 C,10 ml/ kg body weight within 10 minutes)
• Exercise
Subject will be asked to complete four bouts of exercise for 10 min- at 85% of their maximal oxygen consumption (VO2max) with 15-min breaks between each bout
• Meal consumption
Subjects will be asked to consume a high calorie meal (12 kcal/kg, 50% carbohydrates, 30% fat, and 20% protein) within 15 minutes.

Locations

Country	Name	City	State
United States	University of Texas Medical Branch at Galveston	Galveston	Texas

Sponsors (1)

Lead Sponsor	Collaborator
Rutgers University

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Other	Substrate kinetics	We will use a stable isotopes to assess substrate kinetics. Specifically, a primed, constant 4hr infusion of 6,6-D2-glucose to assess glucose kinetics; b) a constant 4hr infusion of potassium uniformly labelled with carbon 13 [U-13C16] palmitate to assess FFA kinetics (27, 28); and c) a primed, constant, 4hr infusion of [1,1,2,3,3-2H5]glycerol dissolved in 0.9% NaCl solution, to assess whole body lipolysis , and) a bolus of labeled with carbon13 sodium bicarbonate(NaHCO3) dissolved in 09% sodium chloride (NaCl) solution to assess substrate oxidation.	During the 8hr study
Other	Thermoregulation	We will use a telemetric pill and wireless thermistors to monitor the body core and skin temperatures of the participants. Moreover, thermal sensation will be assessed using a visual analog scale of the American Society of Heating, Refrigerating, and Air-Conditioning Engineers. Heart rate and blood pressure will be also measured to assess the cardiovascular response to cold exposure.	During the first 5-6 hrs of the cold exposure study
Primary	Insulin Sensitivity	Insulin sensitivity will be measured using the euglycemic hyperinsulinemic insulin clamp method	After 8hrs of cold exposure or thermoneutral conditions
Secondary	Metabolic profile	Evaluation of metabolic profile will include measurement of various metabolites (glucose, triglycerides, very low-density (VLDL)-triglycerides, non-esterified fatty acids, lipoproteins, apo-B) and hormones (leptin, adiponectin, insulin, ghrelin).	During the 8hr trial or on the following day