Synergistic effects of self-assembling peptide and neural stem/progenitor cells to promote tissue repair and forelimb functional recovery in cervical spinal cord injury.

While neural stem/progenitor cells (NPCs) show promise for traumatic spinal cord injury (SCI), their efficacy in cervical SCI remains to be established. Moreover, their application to SCI is limited by the challenges posed by the lesion including the glial scar and the post-traumatic cavitation. Given this background, we sought to examine the synergistic effect of self-assembling peptide (SAP) molecules, designed to optimize the post-traumatic CNS microenvironment, and NSCs in a clinically-relevant model of contusive/compressive cervical SCI. We injected K2(QL)6K2 (QL6) SAPs into the lesion epicenter 14 days after bilateral clip compression-induced cervical SCI in rats, combined with simultaneous transplantation of neural stem/progenitor cells (NPCs) intraspinally adjacent to the lesion epicenter. The QL6 SAPs reduced the volume of cystic cavitation in the spinal cord lesion. Simultaneously engrafted NPCs preserved motor neurons and attenuated perilesional inflammation. The combination of QL6 and NPCs promoted forelimb neurobehavioral recovery and was associated with significant improvement in forelimb print area and stride length. In summary, we report for the first time histologic and functional benefits in a clinically-relevant model of cervical SCI through the synergistic effects of combined SAP and NPCs.