Abstract 14921: Sulfated Dextran-coated Iron Oxide Nanoparticles Detect Inflammation in the Acute Phase of Myocardialsulfated Dextran-coated Iron Oxide Nanoparticles Detect Inflammation in the Acute Phase of Myocardial Infarction

Introduction: We investigated whether the negatively-charged sulfated dextran-coated iron oxide (SDIO) nanoparticles with higher affinity with macrophage can delineate inflammation more efficiently compared to non-sulfated dextran-coated iron oxide (DIO) nanoparticles in mice LAD ligation model. Methods: After mice were induced with LAD ligation, SDIO or DIO nanoparticles (15mg/kg) were injected intravenously at either day 1, day 3, day 5, and day 7. MRI was performed pre- and post-24 hours later. Dephasing signal loss caused by iron-oxide nanoparticles was detected by gradient echo sequence. Iron uptake was quantified by T2* mapping and calculated as delta R2* (=1/T2*(post)-1/T2*(post)) in the region of interest in the infarct, peri-infarct, and remote zones. Results: SDIO injection produced clear signal voids in the peri-infarct zone at day 3 (n=8), which extend into the infarct zone at day 5 (n=3) (figure). The signal was remarkably decreased at day 7 (n=7). Iron uptake represented by delta R2* in the peri-infarct (80.6±35.7 s -1 ) was significantly higher than that in the infarct (32.3±32.6 s -1 , p<0.001) and the remote (5.1±16.7 s -1 , p<0.0001) at day 3. At day 5, delta R2* in the infarct (91.6±5.4 s -1 , p<0.001) and the peri-infarct (41.0±33.3 s -1 ,p=0.04) were significantly higher than the remote (4.2±14.1 s -1 , p<0.001). DIO did not produce significant change in delta R2* in the peri-infarct or infarct at each time phase. The MRI signals of SDIO corresponded with the area of enhanced vascular permeability peaking at day 3-5, which precedes the macrophage infiltration. Conclusions: SDIO can detect inflammation in the peri-infarct region in the early phase of acute myocardial infarction.