Indirect calorimetry system for research in human metabolism - Abstract The Metabolism Core Laboratory at the University of Alabama at Birmingham (UAB) proposes to purchase and install an indirect calorimeter system to support leading research programs in metabolism, nutrition, diabetes, obesity, and other chronic metabolic diseases. Indirect calorimetry, via a whole-room indirect calorimeter system, is the gold standard for measuring gas exchange to estimate energy expenditure (EE) via oxygen consumption and carbon dioxide production, providing precise and accurate measures under regulated environmental conditions. UAB has a history of innovation in studies of metabolism utilizing indirect calorimetry and, in the 1990s, was among the first to install an indirect calorimeter in an academic research facility. This original indirect calorimeter reached the end of its functionality following 20 years of service, and researchers have been required to shift measurement modalities toward mobile metabolic monitors or doubly labeled water, both of which have significant limitations relative to the 24-hour measurement capability of a whole-room indirect calorimeter. Despite these limitations, multiple NIH-funded investigators have incorporated measures of EE into study designs, resulting in high-impact scientific studies and publications while demonstrating a sustained need for the return of whole-room indirect calorimetry capabilities. The room calorimeter system proposed in this application will meet these research needs and provide a replacement for the previous system to again enable appropriate, controlled environmental conditions for both short- and long-term EE measures. Components of daily EE include resting EE, activity-related EE (both exercise/physical activity and non-exercise activity), thermic effect of feeding, respiratory exchange ratio (for nutrient substrate utilization), sleeping metabolic rate, total daily EE, and other measures as required by study designs. While some aspects of these comprehensive EE measures may be collected via a portable metabolic monitor or doubly labeled water techniques, effects on EE associated with nutrition composition, timing of feeding, energy balance, and health and disease states often require the precision and accuracy available only in the whole-room indirect calorimeter system. Combined with the ability to deliver interventions (nutrition, activity, pharmaceutical, environmental), the room calorimeter system will support the current research base and be available to a broad network of investigators connected to the UAB Nutrition Obesity Research Center, Diabetes Research Center, and O’Neal Comprehensive Cancer Center and restore indirect calorimetry capabilities to the state of Alabama and the broader region, where none currently exist.
