Injectable hydrogel embedded with mesenchymal stem cells repairs severe spinal cord injury

Abstract: Mesenchymal stem cell (MSC) transplantation was suggested as a promising approach to treat spinal cord injury (SCI). However, the heterogeneity of MSC and the lack of appropriate delivery methods impede its clinical application. To tackle these challenges, we first generated human MSCs derived from a single cell with a great homogeneity of batch quality and then developed a biocompatible injectable hydrogel to embed these cells to treat severe SCI. In a clinically relevant rat severe SCI model, we showed that the injection of MSC with injectable hydrogel into the lesion site promoted robust functional recovery, while the intrathecal delivery of MSC only resulted in limited therapeutic effects. Mechanistically, the hydrogel protected MSC from the damage of harmful neuroinflammatory microenvironment in the spinal cord lesion. The hydrogel with the survived MSC ameliorates the neuroinflammatory microenvironment of spinal cord lesion, preventing cavity formation and leads to the remnant of spared axons/tissues, which results in a better prognosis in the end.