54. The spatial energy expenditure configuration and possible applications in an experimental model of arthritis

Abstract

Background: Autoimmune responses with differentiation and proliferation of immune cells and the subsequent tissue-directed inflammatory process in the symptomatic phase of the disease are very energy-demanding. As recent calculations demonstrate, the activated immune system needs approximately 25% of the basal metabolic rate. During rheumatoid arthritis, a reallocation of energy-rich fuels to the activated immune system is necessary in order to nourish the inflammatory process. Energy consumption and, thus, ATP generation can be measured by studying consumption of oxygen. Methods: A new technique termed “spatial energy expenditure configuration (SEEC)” is used to demonstrate bodily areas of high energy demand. SEEC is based on removal of tissue during the course of arthritis, and subsequent determination of oxygen consumption. Small weighed pieces of the respective organ with a size of 4 mm are placed in 24-well multidishes with integrated oxygen sensors, which allows for non-invasive detection of oxygen consumption in vitro. Results: In draining lymphoid nodes, we were able to observe a marked increase in oxygen consumption during the course of arthritis. Sympathectomy prior to immunization increases energy consumption in draining lymph nodes, which is most probably a sign of retention of leucocytes in the lymph node. Conclusions: The SEEC technique enables us to identify locations of high energy demand that are involved in the initiation and continuation of the autoimmune process in an animal model of arthritis.