Development of Tissue Engineered Neuromuscular Interfaces from GalSafe Neurons

PROJECT SUMMARY Major peripheral nerve injury (PNI) is classified as an injury with a long defect (≥3cm) or occurring proximally, requiring long regenerative distances of the host nerve to distal structures (distal nerve, target muscle, etc.). These features result in minimal, if any, functional regeneration as the distal nerve and muscle often degenerate before the host nerve is able to reinnervate these structures due to inherently slow regeneration rates. Since current standard clinical practices delay repairing nerve injuries until the patient (in cases of polytrauma) or the injury site is stabilized, functional recovery is often extremely limited. In order to maintain the innervation capability of nerves and muscles following injury, the team at Axonova Medical has developed a proxy for these degenerating axons to maintain or “babysit” the distal structures until the host axons are able to reinnervate the distal targets. This product, the micro-tissue engineered nerve graft (µTENG), which acts as a tissue engineered neuromuscular interface, consists of axon tracts spanning a discrete population of neurons within a hydrogel column. Notably, the diameter of µTENGs is designed to be on the scale of micrometers, making them injectable to facilitate incorporation into current standard of care practices in the clinic. In pre-clinical rodent studies, µTENGs have been seen to extend axons into distal structures post implantation, resulting in babysitting of distal nerve, therefore keeping the muscle receptive to eventual host axon reinnervation. Previously, larger laboratory-grade µTENGs have been fabricated using primary rat and porcine neurons within an agarose microcolumn. Through the Phase I studies, a clinically relevant product was developed and characterized using GalSafe® neurons within a chitosan microcolumn, with a 200-200µm diameter. Through the successful completion of this proposal, we will advance µTENGs to the clinic by establishing current good manufacturing practices (cGMP)-like manufacturing, critical quality attributes, release criteria, and an effective dosing paradigm. We will also complete in vivo studies in a porcine model of PNI to determine the efficacy of µTENGs to promote functional recovery following delayed repair. Successful execution of these studies will accelerate preclinical safety and efficacy studies and will be incorporated in Axonova’s IND application. Overall, µTENGs hold promise in transforming the field of nerve repair by significantly increasing the clinical window for PNI repair.