Recent Strategies in Tissue Engineering for Guided Peripheral Nerve Regeneration

Abstract

The repair of large crushed or sectioned segments of peripheral nerves remains a challenge in regenerative medicine due to the complexity of the biological environment and the lack of proper biomaterials and architecture to foster reconstruction. Traditionally such reconstruction is only achieved by using fresh human tissue as a surrogate for the absence of the nerve. However, recent focus in the field has been on new polymer structures and specific biofunctionalization to achieve the goal of peripheral nerve regeneration by developing artificial nerve prostheses. This review presents various tested approaches as well their effectiveness for nerve regrowth and functional recovery.

Biotechnological Management of Skin Burn Injuries: Challenges and Perspectives in Wound Healing and Sensory Recovery

“…Several bioengineered conduits have already been commercialized for clinical applications in order to replace a sectioned or crushed nerve (169), yet none of these products present a full functional recovery. Moreover, these kind of tridimensional materials do not address directly the problem of skin reinnervation and some modifications in the structure or the shape of the biomaterials are needed to be used to this specific aim.…”

“…Various strategies have been tested in order to give specific functions to the biomaterials either based on structural modifications of the material in order to enhance cell adhesion (205) or to stimulate cell growth at its contact (169). Specifically for neuronal-related application, the option of grafting or adding a neurotrophic factor to the biomaterial has been widely studied.…”

Olfactory Mucosa Mesenchymal Stem Cells and Biomaterials: A New Combination to Regenerative Therapies after Peripheral Nerve Injury

“…They are usually applied to smaller nerves and overcome the disadvantages of the organic options [45]. To ensure its functionality, the characteristics of the NGCs used must comply with all the criteria established for this type of biomaterials: the material used must be (i) biocompatible with the regenerating tissue where it will be applied and should never trigger any local or systemic inlammatory response [46]; (ii) biodegradable, while ensuring mechanical and architectural stability during the regenerative process and resisting to the application of sutures and to inlammatory tissue reaction [47]; (iii) lexible and resistant in a balanced way in order to avoid compression of the regenerating axons and to limit tissue inlammation [48]; (iv) capable of preventing the growth of excessive ibrous tissue associated with the site of injury and reducing the loss of neurotrophic factors secreted by damaged nerve endings [44]; (v) capable to provide an orientation line to the growth cone through a 3-D tubular structure, thereby diminishing misdirection phenomena [49]; (vi) semi-permeable and with pores of adequate diameter that allow the inlux of oxygen and interstitial nutrients to nourish the growing axon that simultaneously prevent the entry of inlammatory cells and the loss of growth factors [50]; technically eicient, ensuring requirements related to production, sterilization, storage and handling [51]. Adapted in each case, these biomaterials must have appropriate dimensions that allow the connection of the nerve defects without tension, and the diameter of the conduit and the thickness of the wall should be suicient to accommodate the two stumps at the nerve ends without any compression being exerted.…”

Biodegradable Nerve Guidance Conduit with Microporous and Micropatterned Poly(lactic‐co‐glycolic acid)‐Accelerated Sciatic Nerve Regeneration

“…Considering that spontaneous nerve regeneration rate is 1 mm per day in humans, functional recovery requires at least 100 days for nerve injuries with distance of approximately 100 mm . However, for more severe injuries with distance up to 200 mm, spontaneous regeneration might have little or no restoration of nerve functions based on clinical treatment cases . Although several efforts have been made to regenerate nerve injury, autologous nerve graft is one of the major therapeutic techniques for peripheral nerve regeneration when nerve injury is occurred even longer than 5 cm .…”