STEM CELL TRACKING: IN VITRO AND IN VIVO APPLICATIONS

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。跟踪标记的干/祖贴壁细胞在体内组织段内的迁移和种子过程。目标是：-帮助确定最佳的播种技术（例如，在组织内或通过动脉/金星注射），使大多数粘附干细胞留在受伤的组织部位。-利用PET开发体内干细胞的独特细胞监测能力。在这个过程中，干细胞是预先标记的thimadine激酶（TK）构建使用lenti载体技术。在细胞标记后，固有的TK切割FHBG PET探针来激活PET信号。在这里，通过允许预先标记的TK干细胞在非特异性时间内粘附在组织成分中，然后在图像采集之前激活PET信号，可以分析体内细胞迁移和聚集的长期研究。-使用MRI阴性对比，我们将同时（与PET一起）监测体内干细胞，因为它们在组织部位内播种。对于这种成像方式，使用独特的微铁颗粒，包括A)外葡聚糖涂层，或B)特异性受体-配体通信（例如EpCAM），以促进铁颗粒的内吞作用，从而使独特的铁浓度位于细胞质内。这种标记过程用于破坏MR信号并促进负信号成像。-量化诱导组织修复所需的细胞数量。-可视化最小聚集体大小的干细胞信号（希望是单细胞悬浮液），当它们在受伤组织的毛细血管床内播种时。目前，干细胞治疗假设种子细胞留在感兴趣的组织内。实际上，许多细胞流经受损组织，并将自己植入全身的各种毛细血管床中。改进的粘着方法是必要的，以可视化细胞的分散，可视化细胞聚集大小，并具体量化留在组织损伤部位的干细胞数量。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. To track labeled stem/progenitor adherent cells as they migrate and seed thoughout in-vivo tissue segements. The goals are: - To help determine the best seeding techniques (e.g. either within tissues or via arterial/venus injections) that would allow most adherent stem cells to remain at the injured tissue sites. - To develop unique cell monitoring capabilities, using PET, of in-vivo stem cells. In this process stem cells are pre-labeled with a thimadine kinase (TK) constructs using lenti vector technologies. After cell labeling, the inherent TK cleaves an FHBG PET probe to activate PET signaling. Here, long term investiagations of in-vivo cell migration and aggregation may be analyzed by allowing pre-labeled TK stemcells to adhere inside tissue components over nonspecific time fames - then activate PET signaling prior to image acquisition. - Using negative contrast MRI, we will concurrently (along with PET) monitor in-vivo stem cells as they are seeded within tissues sites. For this imaging modality, unique micro iron particles that include either A)outer dextran coatings, or B)specific receptor-ligand communications (e.g. EpCAM), are used to promote endocytosis of iron particles such that distinctive iron concentrations are located within the cells cytoplasm. This labeling proces is used to disrupt MR signaling and promote negative signal imaging. - To quantify the amount of cells needed to induce tissue repair. - To visualize a stem cell signal of the smallest aggregate size (hopefully single cell suspensions) as they seed themselves inside capillary beds of injured tissues. At present, stem cell therapies assume that seeded cells remain within the tissues of interest. In reality, many cells flow through the damaged tissues and implant themselves inside various capillary beds throughout the body. Improved tacking methods are necessary to visualize the dispersion of cells, to visualize cell aggregate sizes, and to specifically quantify stem cell numbers that remain at the tissue injury sites.