Human induced pluripotent stem cells generated from intervertebral disc cells improve neurologic functions in spinal cord injury

We generated iPSCs from human intervertebral disc cells which were obtained during spine fusion surgery of patients with spinal cord injury. The disc cell-derived iPSCs (diPSCs) showed similar characteristics to human embryonic stem cells (hESCs) and were efficiently differentiated into neural progenitor cells (NPCs) with the capability of differentiation into mature neurons in vitro. To examine whether the transplantation of NPCs derived from the diPSCs showed therapeutic effects, the NPCs were transplanted into mice at 9 days post-spinal cord injury. We detected a significant amelioration of hind limb dysfunction during the follow up recovery periods. Histological analysis at 5 weeks post-transplantation, we could identify undifferentiated human NPCs (Nestin+) as well as early (TUJ1+) and mature neurons (MAP2+) derived from the NPCs. Furthermore, the NPC transplantation demonstrated a preventive effect on the spinal cord degeneration resulting from the secondary injury. This study revealed that the intervertebral disc, a to-be-waste tissue, removed from the surgical procedure, could provide a unique opportunity to study iPSCs derived from hardly accessible somatic cells in normal situation and also be a useful therapeutic resource to generate autologous neural cells to treat patients suffering from spinal cord injury.

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