Tissue engineering strategies for neural tissue using adult stem cells.

摘要

The inability of the spinal cord to repair and regenerate following injury has been attributed, in part, to a lack of sufficient stem cells that can proliferate and regenerate the cellular phenotypes found in nervous tissue. Stem cells from various sources such as embryonic, neural tissue, and bone marrow, have been tested for recovery of function in the injured spinal cord. Limitations exist in terms of availability, suitability, or potential to differentiate and integrate with host tissure in a functional manner. In this study, human adult stem cells were derived from skeletal muscle and induced into all three of the neural lineages in vitro, by two different methods. Once it was determined that human adult stem cells could differentiate into neural phenotypes, the adult stem cells became a possible treatment for central nervous system injury. The NYU model of spinal cord contusion injury was produced in rats with a weight drop device at T10. Cultured adult stem cells, isolated from the skeletal muscle of an adult ROSA (LacZ+) mouse, were injected into the spinal cord injury site (3 x 105 cells in 10 mul saline). Locomotor function was determined for 6 weeks following injury with the BBB locomotor scale. Transplanted adults stem cells and neural phenotypes were identified immunohistochemically in longitudinal spinal cord sections. Locomotor function was significantly greater in the adult stem cell-injected rats (n=11) than in the saline vehicle-injected (n=6) control rats. The final mean BBB scores for the adult stem cell-injected rats was 9.1 and the final mean BBB scores for the saline injected rats was 5.0 (P0.05). Double fluorescent immunolabeling indicated the presence of adult stem cells expressing markers for neurons, astrocytes, and oligodendrocytes as well as undifferentiated adult stem cells. These results may indicate that adult stem cell implantation is a potential tissue engineering treatment for paralysis due to spinal cord injury.