A Systematic Review of the Effectiveness of Cell-Based Therapy in Repairing Peripheral Nerve Gap Defects

Abstract

<jats:p>Nerve prostheses are widely utilized to reconstruct segmental (gap) defects in peripheral nerves as an alternative to nerve grafting. However, with increasing gap length, the effectiveness of a nerve prosthesis becomes sub-optimal, which subsequently has made repairing larger gaps in peripheral nerves a significant challenge in the field of regenerative medicine. Recently, the structure of nerve prostheses has been significantly revised, which interestingly, has provided a promising avenue for the housing and proliferation of supportive cells. In this systematic review, cell implantation in synthetic nerve prostheses to enhance the regenerative capability of an injured nerve with a focus on identifying the cell type and mode of cell delivery is discussed. Of interest are the studies employing supportive cells to bridge gaps greater than 10 mm without the aid of nerve growth factors. The results have shown that cell therapy in conjunction with nerve prostheses becomes inevitable and has dramatically boosted the ability of these prostheses to maintain sustainable nerve regeneration across larger gaps and helped to attain functional recovery, which is the ultimate goal. The statistical analysis supports the use of differentiated bone-marrow-derived mesenchymal stem cells suspended in oxygen-carrying hydrogels in chitosan prostheses for bridging gaps of up to 40 mm; however, based on the imperfect repair outcomes, nerve grafting should not yet be replaced altogether.</jats:p>

Influence of Touch-Spun Nanofiber Diameter on Contact Guidance during Peripheral Nerve Repair

“…Peripheral nerve repair across large gaps represents a significant clinical challenge and many efforts have focused on the development of implantable polymeric scaffolds as alternatives to autografts. Axon regeneration occurs naturally across short peripheral nerve gaps (<4 cm); however, despite many advancements in the field of tissue engineering, there are no clinical solutions that allow for the repair of large nerve gaps (>4 cm) that are often due to traumatic injury. , When there are not enough nerve tissues to allow for a tension-free anastomosis, common methods such as autografts, allografts, and hollow nerve guidance conduits are used to bridge the nerve gap . Currently available clinically approved nerve conduits are limited to short nerve gap repair. , Autografts are associated with a variety of clinical complications, including painful neuroma formation, limited supply, second incision, and donor-site morbidity, but they are advantageous due to their immunogenetically inert nature …”

“…Axon regeneration occurs naturally across short peripheral nerve gaps (<4 cm); however, despite many advancements in the field of tissue engineering, there are no clinical solutions that allow for the repair of large nerve gaps (>4 cm) that are often due to traumatic injury. 1,2 When there are not enough nerve tissues to allow for a tension-free anastomosis, common methods such as autografts, allografts, and hollow nerve guidance conduits are used to bridge the nerve gap. 3 Currently available clinically approved nerve conduits are limited to short nerve gap repair.…”

Negative Pressure Neurogenesis: A Novel Approach to Accelerate Nerve Regeneration after Complete Peripheral Nerve Transection

“…2 Various modalities to facilitate nerve regenerationsuch as neurotrophic factors-have been described in the literature with limited success. [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] There have been limited reports of applying electrical fields/gradients across a repaired peripheral nerve to speed up axonal regeneration. [27][28][29][30][31] However, the mechanisms by which electrical stimulation enhances nerve regeneration remain relatively poorly understood, and the misdirection of regenerating axons after surgical repair remains a problem for the appropriate activation of re-innervated muscles.…”