Hinds Kathleen A, Hill Jonathan M, Shapiro Erik M, Laukkanen Mikko O, Silva Alfonso C, Combs Christian A, Varney Timothy R, Balaban Robert S, Koretsky Alan P, Dunbar Cynthia E
Hematology Branch, Laboratory of Molecular Biology, Laboratory National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health, Bethesda, MD 20892, USA.
Blood. 2003 Aug 1;102(3):867-72. doi: 10.1182/blood-2002-12-3669. Epub 2003 Apr 3.
Tracking transplanted stem cells using magnetic resonance imaging (MRI) could offer biologic insight into homing and engraftment. Ultrasmall dextran-coated iron oxide particles have previously been developed for uptake into cells to allow MRI tracking. We describe a new application of much larger, micron-scale, iron oxide magnetic particles with enhanced MR susceptibility, which enables detection of single cells at resolutions that can be achieved in vivo. In addition, these larger particles possess a fluorophore for histologic confirmation of cell distribution. We demonstrate highly efficient, nontoxic, endosomal uptake of these particles into hematopoietic CD34+ cells and mesenchymal stem cells documented by confocal and electron microscopy. Labeled cells retain biologic activity with preservation of colony-forming ability and differentiation capacity. MRI studies could detect labeled CD34+ cells and mesenchymal stem cells (MSCs) at single cell resolution. This appears to be a promising tool for serial noninvasive monitoring of in vivo cell homing and localization using MRI.
利用磁共振成像（MRI）追踪移植的干细胞能够为归巢和植入提供生物学见解。此前已开发出超小的葡聚糖包被氧化铁颗粒，可被细胞摄取以实现MRI追踪。我们描述了一种新的应用，即使用更大的、微米级的具有增强磁共振敏感性的氧化铁磁性颗粒，这能够在体内可实现的分辨率下检测单个细胞。此外，这些较大的颗粒带有一种荧光团，用于对细胞分布进行组织学确认。我们通过共聚焦显微镜和电子显微镜证明，这些颗粒能高效、无毒地以内吞方式进入造血CD34+细胞和间充质干细胞。标记后的细胞保留了生物学活性，同时保持了集落形成能力和分化能力。MRI研究能够在单细胞分辨率下检测标记的CD34+细胞和间充质干细胞（MSC）。这似乎是一种很有前景的工具，可用于使用MRI对体内细胞归巢和定位进行连续无创监测。
