IN VIVO DIFFERENTIATION AND MIGRATION PROPERTIES OF STEM CELLS

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. There is increasing evidence that mesenchymal stem cells (MSCs) isolated from the bone marrow or adipose tissue are multipotent cells that can engraft and differentiate in the CNS. MSCs may offer advantages if developed for cell therapy because these cells are relatively easy to isolate from small volume of lipoaspirate or of bone marrow aspirate and can be readily expanded to provide a sufficient number of cells for transplantation. In this study, a series of CNS transplantation experiments were performed to characterize the engraftment, migration, homing, and differentiation patterns of human MSCs. Cell lines generated from human bone marrow derived MSCs (BMSCs) and adipose tissue derived MSC (ASCs) were injected into lateral ventricle of brain of NIHIII immune deficient mice by stereotaxic injection. The fate of MSCs was monitored by immunohistochemistry and PCR analyses 15 and 30 days post-injection. MSCs migrated along ventricular area both rostrally and caudally from the injection site. Cells were distributed throughout the entire rostro-caudal extent of ventricular zone. Many MSCs also were detected lining the ependyma throughout the ventricle. A significant number of donor cells were distributed along the length of the spinal cord. A higher frequency of MSCs was detected in animals injected with ASCs than BMSCs at 15 days following injection. Donor cells were dispersed into both lobes of the brain, numerous cells were detected in the cortex and different areas of cerebrum such as semilunar lobules, paraflocculus, postsuperior, fissure areas, and external and internal granular layers. Detailed analysis revealed that MSCs were predominantly seen in perivascular space in the brain. In animals injected with ASCs, the total number of detectable cells was significantly higher in 30 days post-engraftment than 15 days, though the distribution pattern was unchanged. A significantly higher number of engrafted BMSCs were detected in the spinal cord of 30 days group. BMSCs were widely distributed throughout the brain at both time points. The distribution pattern of BMSCs at 15 days post engraftment was similar to ASCs. At 30 days, the majority of cells were found in the ventral areas of brain, with many detected in the immediate periphery of basilary artery. The results form these studies suggest that the MSCS effectively migrate throughout the CNS via the cerebrospinal fluid, as the pattern of detection of cells parallels the flow of cerebrospinal fluid in the brain. Numerous MSCs were found to be reactive to some specific neuronal antibodies such as NSE and MAP-2 at 30 days following engraftment indicating the differentiation of the grafted cells. The results of these studies demonstrated that transplantation of both types of MSCs into the ventricle resulted in the migration of MSCs throughout the brain within striatal, cortical, and cerebellar regions as well as and spinal cord.