Haosen Zhang1, Chih-Lung Chen2, Qing Ye1, Kevin Hitchens1, Wen-Yuan Hsieh2, Hsiu-Hua Huang2, Yi-Shan Lin2, HsinHsin Shen2, Mu-Jen Young2, Wei-Lin Yu2, Ying-Ting Huang2, Lesley Foley1, Yijen Wu1, Jassy Wang2, Chien Ho1
1Pittsburgh NMR Center for Biomedical Research, Department of Biological Science , Carnegie Mellon University, Pittsburgh, PA, USA; 2Industrial Technology Research Institute, Taiwan
The aim of this study was to detect the macrophage accumulation by in vivo MRI in a rat heterotopic heart transplantation model of acute rejection using a biodegradable, nano-sized iron oxide particle with high relaxivity. After being labeled ex vivo with ITRI-IOP, punctuate spots of hypointensity were observed on the mid-wall of the transplant heart 24 hrs post injection. Ex vivo imaging of the fixed heart demonstrated abundance of punctuated spots of hypointensity that might be caused by the iron-loaded macrophages. Histological analysis and iron staining confirmed the presence of iron and macrophages in the corresponding tissue section as MRI.