Tissue‐Engineered Peripheral Nerve

Abstract

Peripheral nerves can be injured by a variety of mechanisms but can regenerate on their own if the injury is not extensive. Nerve grafts, the current standard of surgical care for repairing large nerve gaps, are successful, but they can be associated with several major drawbacks. To overcome these disadvantages, researchers are designing “off‐the‐shelf” nerve guide implants; thus, a multidisciplinary effort is underway to engineer nerve repair through a deeper understanding of the dynamic cell–cell and cell–environment interactions that occur during regeneration. This entry, which focuses on literature published in the last 5 years, first emphasizes new nerve guide designs that have been demonstrated to improve functional regeneration in vivo . The second section reviews studies that have deepened our understanding of in vitro and in vivo neural regenerative responses via new biomaterials technologies and imaging techniques. These critical advancements in peripheral nerve tissue engineering provide templates for future mechanistic studies and improved strategies to aid functional regeneration in vivo .

Stem Cells and Nanostructures for Advanced Tissue Regeneration

“…Injury typically results in the loss of motor and sensory function, or both [153]. Neural diseases represent a very complicated and significant clinical problem; for example, in the USA alone, there are about 250,000-400,000 people living with spinal cord injury and nearly 13,000 additional people suffer spinal cord injuries each year [154].…”

Additive manufactured biodegradable poly(glycerol sebacate methacrylate) nerve guidance conduits

“…Commonly the sensory sural nerve, which innervates the foot, is used. However, studies have shown a loss in sensitivity and pain can be caused by the removal of the sural nerve [3,9,10]. The requirement of multiple surgeries is not unusual and there are a limited number of autologous donor nerves available.…”

“…The requirement of multiple surgeries is not unusual and there are a limited number of autologous donor nerves available. Allografts are undesirable due to the need for immunosuppressants [3,11,12].…”

“…This takes the form of a biocompatible tube of either natural or synthetic materials, used to bridge the nerve gap, minimize axonal dispersion, direct Schwann cell migration, prevent scar formation and create an appropriate microenvironment for nerve repair [3].S y nthetic polymer NGCs allows for control over reproducibility and degradation rates of nerve guides, however there may be a lack of cell migration and biological integration. Natural materials (e.g.…”

Salicylic acid‐derived poly(anhydride‐ester) electrospun fibers designed for regenerating the peripheral nervous system

“…The biomedical functionality of aligned fiber constructs has been demonstrated with several types of cells (fibroblasts,24 endothelial cells,25 smooth muscle cells,26 and chondrocytes27) orientating parallel to aligned fibers. For the peripheral nervous system, previous research has demonstrated that regenerating axons follow winding, inefficient pathways, often resulting in misdirected re‐enervation between sensory and motor axons and their targets 28, 29. Aligned fibers within an NGC afford favorable topographical features for proficient glial and axon guidance from nerve stump to nerve stump.…”