The Metabolic Unit within HDDC Core D: Gnotobiotic Mice, Microbiology and Metagenomics exists to provide the Harvard Medical School and area scientific community with access to cutting-edge resources for the comprehensive measurement and analysis of feeding and metabolism in mice.
The Energy Balance Core provides an extensive and growing variety of services to measure a range of metabolic parameters in mice, including: oxygen consumption (VO2), carbon dioxide production (VCO2), respiratory exchange ratios (RER), food consumption, basal locomotor activity levels, core body temperature and heart rate, body composition, heat lost due to thermal radiation, food metabolism efficiency, and exercise tolerance. Our indirect calorimeters are specialized, allowing for the precise control of ambient temperature ranging from thermoneutrality (30°C) to cold (4°C). The use of indirect calorimetry in our studies has revealed profound changes in energy substrate utilization and induction of thermogenesis in multiple mouse models. We also have the ability to moniter germ-free mice. Germ-free mice can be examined using isolator cages. With this approach, we can examine the metabolic profile of germ-free mice or mice colonized with specific microbes.
The Metabolic Unit offers a full suite of services for the analysis of mouse metabolism. The core’s Columbus Instruments Comprehensive Lab animal Monitering (CLAMS) system allows for simultaneous measurement of key metabolic parameters in mice.
The CLAMS is complemented by other instruments that allow for noninvasive quantitation of whole-body fat and lean mass; EchoMRI Body Composition Analyzers and DEXA for the precise measurement of body composition, a thermal imaging system for the measurement of heat lost due to thermal radiation (FLIR camera), an oxygen bomb calorimetry for the assessment of food metabolism efficiency in mice, and energy consumed but not absorbed (fecal bomb calorimetry). We also utilize continuous glucose monitoring in mice with the Data Sciences International (DSI) HD-XG system. As of summer 2021, we also measure non-invasive isotopic substrate oxidation in live mice with 13C-glucose or other substrates when metabolized to 13CO2.
New software available from the Metabolic Unit:
- CalR – A web Application for Indirect Calorimetry Analysis
People and contact information
Director: Alexander S. Banks, PhD
Core Manager: Marissa Cortopassi
Location
BIDMC Center for Life Sciences
330 Brookline Avenue, CLS 728
Boston, MA, 02115
Services
Comprehensive Lab Animal Monitoring System (CLAMS)
The Columbus Instruments Comprehensive Lab Animal Monitoring System (CLAMS) is a system of metabolic cages which allows for simultaneous measurement of numerous metabolic parameters including oxygen consumption (VO2), carbon dioxide production (VCO2), respiratory exchange ratio (RER), food consumption, locomotor activity levels, and (using implantable transmitters) core body temperature and heart rate.
The cages are enclosed in a light- and temperature-controlled environment, enabling the user to collect data at varied ambient temperatures. Each runs lasts 3-12 days depending on the requirements of varying ambient temperatures or dosing schedule for exogenous compounds. Typically, mice are allowed to acclimate in the cages for 2 days and then data are collected for 1 day. When varying the ambient temperature, mice are again acclimated for 2 days followed by 1 day of data collection. To monitor core body temperatures, surgery to implant temperature transmitters is performed one week prior to entering the CLAMS. This allows mice to fully recover from surgery prior to experiments.
EchoMRI
The BWH Metabolic Core has acquired two EchoMRI 3-in-1 Body Composition Analyzers. These instruments provide precise body composition measurements of fat, lean, free water, and total water masses in either tissue samples or live animals weighing up to 100 grams.
As well as providing important data in its own right, the ability to measure body composition is critical to interpretation of metabolic rates.
Germ-Free CLAMS Cages
The BWH Metabolic Core has 6 germ-free CLAMS cages available for CLAMS studies. Germ-free mice will be housed in individually ventilated cages and maintained in sterile conditions, on a commercial laboratory diet. The CLAMS studies include measurement of numerous metabolic parameters including oxygen consumption (VO2), carbon dioxide production (VCO2), respiratory exchange ratio (RER), food consumption, locomotor activity levels, and (using implantable transmitters) core body temperature and heart rate.
FLIR Infrared Camera
The BWH Metabolic Core FLIR T420SC Thermal Imaging Camera and ResearchIR software enable users to measure heat lost due to thermal radiation, a potentially significant mechanism of weight loss and energy homeostasis.
The camera allows imaging resolution to within 0.2C, allowing for the measurement of vasodialation or constriction.
Oxygen Bomb Calorimetry
A Parr 6725EA Semimicro Calorimeter and 1107 Oxygen Bomb allow the BWH Metabolic Core to measure the energy content of fecal waste from mice following different genetic or environmental stimuli, enabling crucial assessment of food metabolism efficiency in experimental mice.
Pricing
Pricing and other information and services can be found at metabolic.bwh.harvard.edu.