MR Unit, Department of Radiodiagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Prague, Czech Republic.
Center for Advanced Preclinical Imaging, First Faculty of Medicine, Charles University, Prague, Czech Republic.
Mol Imaging Biol. 2019 Jun;21(3):454-464. doi: 10.1007/s11307-018-1270-3.
Combining specific and quantitative F-19 magnetic resonance imaging (MRI) with sensitive and convenient optical imaging provides complementary information about the distribution and viability of transplanted pancreatic islet grafts. In this study, pancreatic islets (PIs) were labeled with positively charged multimodal nanoparticles based on poly(lactic-co-glycolic acid) (PLGA-NPs) with encapsulated perfluoro-15-crown-5-ether and the near-infrared fluorescent dye indocyanine green.
One thousand and three thousand bioluminescent PIs were transplanted into subcutaneous artificial scaffolds, which served as an alternative transplant site. The grafts were monitored using in vivo F-19 MR, fluorescence, and bioluminescence imaging in healthy rats for 2 weeks.
Transplanted PIs were unambiguously localized in the scaffolds by F-19 MRI throughout the whole experiment. Fluorescence was detected in the first 4 days after transplantation only. Importantly, in vivo bioluminescence correlated with the F-19 MRI signal.
We developed a trimodal imaging platform for in vivo examination of transplanted PIs. Fluorescence imaging revealed instability of the fluorescent dye and its limited applicability for longitudinal in vivo studies. A correlation between the bioluminescence signal and the F-19 MRI signal indicated the fast clearance of PLGA-NPs from the transplantation site after cell death, which addresses a major issue with intracellular imaging labels. Therefore, the proposed PLGA-NP platform is reliable for reflecting the status of transplanted PIs in vivo.
将特异性和定量的 F-19 磁共振成像（MRI）与敏感和便捷的光学成像相结合，可提供有关移植胰岛移植物分布和活力的互补信息。在这项研究中，胰岛（PIs）用基于聚（乳酸-共-乙醇酸）（PLGA-NPs）的带正电荷的多模态纳米颗粒进行标记，这些纳米颗粒封装了全氟-15-冠-5-醚和近红外荧光染料吲哚菁绿。
将 1000 个和 3000 个生物发光胰岛移植到皮下人工支架中，作为替代移植部位。在健康大鼠中，通过体内 F-19 MR、荧光和生物发光成像监测移植后 2 周的移植物。
在整个实验过程中，F-19 MRI 可明确定位移植到支架中的胰岛。仅在移植后第 4 天检测到荧光。重要的是，体内生物发光与 F-19 MRI 信号相关。
我们开发了一种用于体内检查移植胰岛的三模态成像平台。荧光成像显示荧光染料的不稳定性及其对纵向体内研究的有限适用性。生物发光信号与 F-19 MRI 信号之间的相关性表明，在细胞死亡后，PLGA-NPs 从移植部位快速清除，这解决了细胞内成像标记物的一个主要问题。因此，所提出的 PLGA-NP 平台可可靠地反映体内移植胰岛的状态。
