An experiment conducted by a team of Japanese researchers from the Keio University School of Medicine, offers new hope for patients with spinal cord injuries. They managed to obtain motor functional recovery after injecting neural stem / progenitor cells (NS / PCs ) in mice. It was known for some time that transplantation of neural stem / progenitor cells (NS / PCs ) promotes functional recovery in spinal cord injury, but it was not very clear what is the optimal transplantation site. Therefore, researchers made an experiment in which they injected NS / PCs in four groups of mice in several sites : at the lesion epicenter, caudal and rostral sites; the control group received phosphate buffered saline. It should be noted that all mice included in the study received contusive spinal cord injury at the T10 level.
Dr. Masaya Nakamura of the Department of Orthopedic Surgery at the Keio University School of Medicine, emphasized that it is critical to determine the optimal site for transplanting NS / PCs designed to treat spinal cord injury. Previous studies conducted by the same team showed that NS / PCs injected intravenously or intrathecally in non – injury sites, did not engraft at the lesion site in sufficient numbers; the researchers observed that instead these NS / PCs were trapped in the lungs or kidney. In this way they concluded that the optimal outcome for transplantation of NS / PCs can be obtained by intralesional application. To determine how effective is intralesional injection, researchers conducted another study on laboratory mice with spinal cord injury. They injected NS / PCs taken from transgenic mice for Venus and luciferase fusion protein, a method that allowed the researchers to track the cells after transplantation by bioluminescence imaging ( BLI ).
Dr. Nakamura explained that wild-type mice received a spinal cord injury at T10 and that low and high doses of NS / PCs taken from fetal transgenic mice were administered to four groups of mice; the fifth group received phosphate buffered saline. Researchers reported that all four groups of mice had functional motor recovery while mice in the control group did not. The researchers also mentioned that in all four groups, the photon counts from BLI transplant were similar. In other words, the survival of stem cells was uniform when it was transplanted more than a certain threshold number of cells. However, it seems that there is a difference between rostral and caudal (RC ) sites and lesion epicenter (E ) because brain -derived neurotropic factor expression was higher in RC. “This may mean that the microenvironments of the E and RC sites are similarly able to support NS/PCs transplanted during the sub-acute phase of SCI,” researchers said.