Growth factor enhancement of peripheral nerve regeneration through a novel synthetic hydrogel tube

Object. The authors’ long-term goal is repair of peripheral nerve injuries by using synthetic nerve guidance devices that improve both regeneration and functional outcome relative to an autograft. They report the in vitro processing and in vivo application of synthetic hydrogel tubes that are filled with collagen gel impregnated with growth factors.Methods. Poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) (PHEMA-MMA) porous 12-mm-long tubes with an inner diameter of 1.3 mm and an outer diameter of 1.8 mm were used to repair surgically created 10-mm gaps in the rat sciatic nerve. The inner lumen of the tubes was filled with collagen matrix alone or matrix supplemented with either neurotropin-3 at 1 g/ml, brain-derived neurotrophic factor at 1 g/ml, or acidic fibroblast growth factor (FGF-1) at 1 or 10 g/ml. Nerve regeneration through the growth factor–enhanced tubes was assessed at 8 weeks after repair by histomorphometric analysis at the midgraft level and in the nerve distal to the tube repair. The tubes were biostable and biocompatible, and supported nerve regeneration in more than 90% of cases. Nerve regeneration was improved in tubes in which growth factors were added, compared with empty tubes and those containing collagen gel alone (negative controls). Tubes filled with 10 g/ml of FGF-1 dispersed in collagen demonstrated regeneration comparable to autografts (positive controls) and showed significantly better regeneration than the other groups.Conclusions. The PHEMA-MMA tubes augmented with FGF-1 in their lumens appear to be a promising alternative to autografts for repair of nerve injuries. Studies are in progress to assess the long-term biocompatibility of these implants and to enhance regeneration further

Characterization of neural stem cells on electrospun poly(epsilon-caprolactone) submicron scaffolds: evaluating their potential in neural tissue engineering

Development of biomaterials with specific characteristics to influence cell behaviour has played an important role in exploiting strategies to promote nerve regeneration. The effect of three-dimensional (3D) non-woven electrospun poly(ε-caprolactone) (P

Tissue engineered alternatives to nerve transplantation for repair of peripheral nervous system injuries

To date the best regenerative strategies to repair peripheral nerve injuries (PNI) have used peripheral nerve grafts.[1] However, this strategy is inherently flawed, requiring that a second injury be created to harvest the tissue for the primary injury repair. A better strategy would be to prepare a synthetic graft that mimics the properties of a peripheral nerve graft. Non-nerve biologic tissue and synthetic biodegradable material as bridges for neural repair have been utilized for over a century (reviewed by Doolabh et al [2]). Although offering considerable promise, artificial conduits have had only limited success, possibly due to their simple design and the lack of multiple stimuli of regeneration. In developing a bioengineered nerve graft, we have been systematically investigating a number of strategies to optimize nerve regeneration through tubular devices. We report our initial results with the use of bioengineered nerve grafts for repair of PNI in a rat model