Department of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Songpagu, Seoul, South Korea.
Radiology. 2010 Sep;256(3):847-54. doi: 10.1148/radiol.10091732.
To evaluate the feasibility of MR imaging to depict the in vivo recruitment of superparamagnetic iron oxide (SPIO)-labeled macrophages and to aid diagnosis of graft rejection in kidney transplantation.
This study was approved by the institution's committee on animal research. Eighteen male Lewis rats received a kidney transplant; 12 had an F344 rat donor and six had a Lewis rat donor. Peritoneal macrophages were harvested from thioglycollate-treated Lewis rats, cultured, and labeled with SPIO. After resuspension of macrophages in a concentration of 1 x 10(7) cells per milliliter of Hanks balanced salt solution, 5 x 10(6) of SPIO-labeled macrophages was administered through the tail vein 2 or 5 days after transplantation in each group. The transplanted kidneys were imaged on a 4.7-T MR imager 24 hours after macrophage administration. The Wilcoxon signed rank test was performed for evaluating the differences between the relative signal intensity (SI) before and after SPIO-labeled macrophage administration.
A low-SI zone was predominantly noted in the medulla of the transplanted kidneys, and the relative SI decreased significantly from 1.40 to 0.53 (P < .001) in the allogeneic transplants following SPIO-labeled macrophage administration 5 days after the allogeneic transplantation. In the syngeneic group, the lower-SI zone was not noted in the grafts. At histopathologic examination, the lower-SI zone corresponded to the distribution of the SPIO-labeled macrophages.
This study demonstrates that the homing of intravenously administered SPIO-labeled macrophages can be monitored in the allograft rejection model on in vivo MR images.
评估磁共振成像（MRI）在活体显示超顺磁氧化铁（SPIO）标记的巨噬细胞募集情况中的可行性，并辅助诊断肾移植中的移植物排斥反应。
本研究获得了机构动物研究委员会的批准。18 只雄性 Lewis 大鼠接受了肾移植；其中 12 只接受了 F344 大鼠供体，6 只接受了 Lewis 大鼠供体。从巯基葡萄糖酸盐处理的 Lewis 大鼠中收获腹腔巨噬细胞，进行培养并标记 SPIO。将巨噬细胞重悬于浓度为 1×10(7)个细胞/毫升的 Hank's 平衡盐溶液中，在每组大鼠移植后第 2 天或第 5 天经尾静脉给予 5×10(6)个 SPIO 标记的巨噬细胞。在巨噬细胞给药后 24 小时，在 4.7-T MR 成像仪上对移植肾进行成像。采用 Wilcoxon 符号秩检验评估 SPIO 标记的巨噬细胞给药前后相对信号强度（SI）的差异。
在移植肾的髓质中主要观察到低 SI 区，并且在同种异体移植后第 5 天 SPIO 标记的巨噬细胞给药后，相对 SI 从 1.40 显著降低至 0.53（P<0.001）。在同基因组中，未在移植物中观察到低 SI 区。在组织病理学检查中，低 SI 区与 SPIO 标记的巨噬细胞的分布相对应。
本研究表明，在活体 MRI 图像上可以监测静脉内给予的 SPIO 标记的巨噬细胞在同种异体移植排斥反应模型中的归巢情况。
