Abstract 858: Change in Body Sodium Content in PPAR agonist Treatment Detected with Sodium MRI
As an effective insulin sensitizer, rosiglitazone, is currently used for the treatment of hyperglycemia in type 2 diabetes. Its treatment, however, is associated with some common side effects, which include weight gain, fluid retention, etc. Since the body weight gain is partially due to the fluid retention in the form of edema, which is in the form of sodium-rich, extracellular fluid accumulation in tissues, total body sodium is expected to increase as a consequence. Therefore, sodium imaging provides a needed tool for assessing the change in body sodium content. In this study, increase in total body sodium of mice treated with rosiglitazone was quantified non-invasively with sodium MR imaging. Four mouse groups were involved: two wild-type C57 mouse groups (control vs treated, N=6/group) and two PPAR-gamma VEC KO mouse groups (control vs treated, N=6/group). Mice were treated with rosiglitazone (100mpk/day) or vehicle for 14 days. The sodium measurement was done using a Bruker 9.4T MRI system (94/31 Biospec, Ettlingen, Germany). Sodium imaging method was based on a gradient-echo scheme (TR/TE=70/0.90msec, flip angle=60, NSA=4). During imaging, mice were anesthetized with isofluorane (1.0–1.5% iso/O2). The total body sodium was obtained by integrating sodium MR signals from the resulting sodium images. Results showed that total body sodium increased following the treatment in wild type mice (p=0.014) while not in the KO mice (p=0.5). The mean percentage changes in the total body sodium content were 15.3+/−0.4% and 0.1+/−0.1% in wild type and KO groups respectively. This study demonstrates a potential use of the sodium imaging method in quantifying whole body sodium content, which is an important component of weight gain in rosiglitazone treatment. And, the method is translatable to human.