In vivo implant of a new generation of neural collagen-based guides

The use of a tubular construct (termed conduit) to reconnect the proximal and distal stumps of a transected nerve, and induce regeneration of the lost nerve trunk, has been the subject of a large number of investigations. While the presence of a conduit between the transected stumps is sufficient to induce regeneration, the microstructural, mechanical and compositional features of the tubular construct itself, and of any material inserted within the tube lumen, have been observed to significantly affect the quality of regeneration. An ideal conduit should protect the site of injury from the infiltration of surrounding tissues, at the same time retaining a certain degree of porosity to allow diffusion of soluble factors (SFs) through the tube wall. Moreover, it should affect the migration and organization of myofibroblasts, which are responsible for the undesired synthesis of scar tissue. The conduit should also provide adequate mechanical strength and flexibility to support the regenerating nerve fibers, and should be biocompatible and biodegradable.Pioneering studies on peripheral nerve regeneration made extensive use of biodurable conduits, such as silicone tubes and, recently, a wide variety of biodegradable materials, including synthetic and natural polymers, and different conduit geometries have been examined. Collagen has been identified as one of the most promising materials for the production of conduits due to its biocompatibility and the observed enhanced cell attachment within collagen scaffolds. A new type of neural guide based on highly engineered collagenic porous matrices has been developed and patented. They are characterized by the presence of a radially micropatterned porosity, obtained acting on the thermodynamic of crystallization and playing with a sedimentation effect promoted by a spinning device. A full in vivo preclinical study has been performed and the approval from the ethical committee of the San Raffaele Hospital has been obtained to perform an human study on the regeneration of the sural nerve