Application of amniotic fluid stem cells in repairing sciatic nerve injury in minipigs

Many studies have demonstrated that combining nerve conduits with neural stem cells or growth factors can repair peripheral nerve injury in rodents. However, nerve damage does occur with longer gaps in human than in rodents, thus findings from rodent studies are difficult to translate to clinical practice. Minipigs have a longer gap that is more closely applicable to the challenge of human nerve grafting in extensive traumatic nerve damage. In this study, human amniotic fluid stem cells (AFSCs) and polylactate nerve conduits were used to repair sciatic nerve injury in minipigs. The AFSCs exhibited the properties of mesenchymal stem cells with a propensity toward neural stem cells. Measurements of compound muscle action potential implied that administration of conduits with AFSCs was beneficial in function recovery in the minipig model compared with conduits alone. The results of diffusion tensor magnetic resonance imaging (DTI) based fiber tractography assay in the minipig model suggest that combining AFSCs with conduits could expedite the repair of sciatic nerve injury. Further, MR-based DTI provides an effective and non-invasive method to visualize the sciatic nerve and to monitor the regeneration progress of injured nerve in a longitudinal study.