Preclinical evaluation of aligned fibrin nanofibre hydrogels in a non-human primate model of spinal cord injury: A pilot study.

Spinal cord injury (SCI) often leads to partial or complete loss of motor, sensory, and autonomic functions. We have previously shown that the transplantation of hierarchically aligned fibrin nanofibre hydrogel scaffolds (AFGs) facilitates robust neuroregeneration and functional recovery in rat and dog SCI models. Given these positive results, we aimed to evaluate the biosafety and efficacy of AFGs in a non-human primate SCI model before exploring its potential in the clinic. In the present study, no significant adverse reactions were observed over 24 weeks following AFG implantation into 1-cm gaps in the hemisected thoracic spinal cords of monkeys (Macaca fascicularis). Scaffold implantation also reduced cystic cavity formation and encouraged axonal sprouting across the lesion site. Notably, detailed histological analysis demonstrated that AFG promoted high-density, sequential, and aligned nerve fibre regeneration, resulting in remyelination and vascularisation, ultimately leading to remarkable motor function recovery. These results indicate that AFG transplantation exhibits reliable biocompatibility and effectiveness in promoting spinal cord repair in a non-human primate SCI model. Owing to the similarities in genetics and physiology between non-human primates and humans, AFG transplantation therapy is likely suitable for use in human spinal cord repair.