Autologous exosome facilitates load and target delivery of bioactive peptides to repair spinal cord injury

Spinal cord injury (SCI) causes motor, sensory and automatic impairment due to rarely axon regeneration. Developing effective treatment for SCI in the clinic is extremely challenging because of the restrictive axonal regenerative ability and disconnection of neural elements after injury, as well as the limited systemic drug delivery efficiency caused by blood spinal cord barrier. To develop an effective non-invasive treatment strategy for SCI in clinic, we generated an autologous plasma exosome (AP-EXO) based biological scaffold where AP-EXO was loaded with neuron targeting peptide (RVG) and growth-facilitating peptides (ILP and ISP). This scaffold can be targeted delivered to neurons in the injured area and elicit robust axon regrowth across the lesion core to the levels over 30-fold greater than naïve treatment, thus reestablish the intraspinal circuits and promote motor functional recovery after spinal cord injury in mice. More importantly, in ex vivo, human plasma exosomes (HP-EXO) loaded with combinatory peptides of RVG, ILP and ISP showed safety and no liver and kidney toxicity in the application to nude SCI mice. Combining the efficacy and safety, the AP-EXO-based personalized treatment confers functional recovery after SCI and showed immense promising in biomedical applications in treating SCI. It is helpful to expand the application of combinatory peptides and human plasma derived autologous exosomes in promoting regeneration and recovery upon SCI treatment.