Bridging Extended Nerve Defects with an Artifcial Nerve Graft Containing Schwann Cells Pre-Seeded on Polyglactin Filaments

Abstract

A 24 mm long bioartificial nerve graft (BNG) was created to bridge extended peripheral nerve defects of the rat sciatic nerve. In our previous studies, an identical graft had demonstrated good results over nerve gaps of up to 15 mm. The BNG device comprised a collagen-I tube filled with ten Schwann-cell-seeded polyglactin filaments and 106 isogenic Schwann cells suspended in Matrigel which were implanted in 27 rats (group I). Schwann-cell-free grafts (27 rats) and nerve autografts (18 rats) served as controls. Functional recovery was followed over a period of six months using walking track analysis. Terminal analyses of graft efficacy included neurophysiology, muscle weight, and histological assessment of the implants and the distal nerve stumps. In 17/27 cases, axonal regeneration into the distal nerve stump could be detected across the BNG, but all animals in group I and II failed to regain motor function of the hindlimb upon completion of the experiment. Axon diameter and axonal density in the graft and distal nerve stump were greater in group I than in group II. Although Schwann cells had a significant positive effect on axonal regeneration, either granuloma formation or the amount of the inserted foreign material may have impaired nerve regeneration by acting as a physical impediment to nerve regeneration or negatively effecting cell function.

Behavioral evaluation of regenerated rat sciatic nerve by a nanofibrous PHBV conduit filled with Schwann cells as artificial nerve graft

“…Isogeneic SC-seeded guides gave a lower recovery result, while syngeneic SCs did not appear to enhance the regeneration process. Lohmeyer et al (2007) fi lled a collagen conduit with polyglactin (a synthetic absorbable polyester commonly used as suturing material) fi laments seeded with SCs and isogenic SCs suspended in Matrigel and used it to repair a 20-mm sciatic nerve gap in a rat model. Although the number of myelinated axons, which crossed the gap to reach the distal stump, was signifi cantly greater in the SC-seeded conduits than those in unseeded ones, the number of regenerated axons was still insuffi cient to regain the motor function.…”

Biodegradable Cell-Seeded Nanofiber Scaffolds for Neural Repair

“…Isogeneic Schwann cell-seeded guides gave a lower recovery result, while syngeneic Schwann cells did not appear to enhance the regeneration process [209]. Lohmeyer et al [210] filled a collagen conduit with polyglactin (a synthetic absorbable polyester commonly used as suturing material) filaments seeded with Schwann cells and isogenic Schwann cells suspended in Matrigel and used it to repair a 20-mm sciatic nerve gap in a rat model. Although the number of myelinated axons, which crossed the gap to reach the distal stump, was significantly greater in the Schwann-cell seeded conduits than those in unseeded ones, the number of regenerated axons was still insufficient to regain the motor function.…”

“…Although the number of myelinated axons, which crossed the gap to reach the distal stump, was significantly greater in the Schwann-cell seeded conduits than those in unseeded ones, the number of regenerated axons was still insufficient to regain the motor function. This might be due to granuloma formation or the foreign body reaction caused by degraded polyglactin filaments, which either physically hindered the regeneration process or adversely affected cell function [210]. Ishikawa et al examined the effect of chitosan gel sponges containing BMSC derived Schwann cells on peripheral nerve regeneration using a rodent model and concluded that the Schwann-cell seeded chitosan sponge could be a good potential candidate for neural repair [211].…”

Tissue Engineering Strategies Designed to Realize the Endogenous Regenerative Potential of Peripheral Nerves

“…The Schwann cell conduits resulted in larger axonal densities and diameters than the controls without Schwann cells. [129] To attempt to achieve results comparable to those produced by autografts, small intestinal submucosa (SIS) conduits filled with Schwann cells were implanted. These conduits were more effective than conduits without Schwann cells.…”