Can a Small Intestine Segment Be an Alternative Biological Conduit for Peripheral Nerve Regeneration?

Abstract

Background:Autologous nerve grafts are used to bridge peripheral nerve defects. Limited sources and donor site morbidity are the major problems with peripheral nerve grafts. Although various types of autologous grafts such as arteries, veins and muscles have been recommended, an ideal conduit has not yet been described.Aims:To investigate the effectiveness of a small intestinal conduit for peripheral nerve defects.Study Design:Animal experimentation.Methods:Twenty-one rats were divided into three groups (n=7). Following anaesthesia, sciatic nerve exploration was performed in the Sham group. The 10 mm nerve gap was bridged with a 15 mm ileal segment in the small intestinal conduit group and the defect was replaced with orthotopic nerve in autologous nerve graft group. The functional recovery was tested monthly by walking-track analysis and the sciatic functional index. Histological evaluation was performed on the 12th week.Results:Sciatic functional index tests are better in autologous nerve graft group (-55.09±6.35); however, during follow-up, progress in sciatic functional index was demonstrated, along with axonal regeneration and innervation of target muscles in the small intestinal conduit group (-76.36±12.08) (p<0.05). In histologic sections, distinctive sciatic nerve regeneration was examined in the small intestinal conduit group. The expression of S-100 and neurofilament was observed in small intestinal conduit group but was less organised than in the autologous nerve graft group. Although the counted number (7459.79±1833.50 vs. 4226.51±1063.06 mm2), measured diameter [2.19 (2.15-2.88) vs. 1.74 (1.50-2.09) µm] and myelin sheath thickness [1.18 (1.09-1.44) vs. 0.66 (0.40-1.07) µm] of axons is significantly high in the middle sections of autologous nerve graft compared to the small intestinal conduit group, respectively (p<0.05), the peripheral nerve regeneration was also observed in the small intestinal conduit group.Conclusion:Small intestinal conduit should not be considered as an alternative to autologous nerve grafts in its current form; however, the results are promising. Even though the results are no better than autologous nerve grafts, with additional procedures, it might be a good alternative due to harvesting abundant sources without donor site morbidity.

Engineered Neural Tissue Made Using Hydrogels Derived from Decellularised Tissues for the Regeneration of Peripheral Nerves

“…Desirable features of NGCs include biocompatibility with the surrounding tissue, flexibility, the ability to be sutured into the injury site, and the incorporation of chemotactic, structural, and topographical cues for directional axonal regeneration [3,4]. Tissue derived NGCs have included autologous transplants of skeletal muscle, with its basal lamina and anisotropy, tendon, and vein [5], or rinsed small intestinal segments [6], with each displaying variable abilities to repair peripheral nerve lesions. Decellularised nerve allografts have shown promise in bridging small gap injuries [1,2] and, whilst they contain tissue specific ECM, they lack the necessary cellular support required for regeneration across long gaps [2,7].…”