Femke Mathot

Chapter 8 138 implicate that this combination by definition results in less nerve regeneration enhancement that the combination of MSCs and the NeuraGen® Nerve Guide. In vivo studies using the described techniques should indicate whether MSC-seeding location (inner or outer surface) has implications for their effect on nerve regeneration. Seeding efficiency was indirectly determined by cell-counts in the supernanent after the seeding duration time passed. Although multiple cell counts were performed with small standard errors and subjective assessment of the obtained live/dead and Hoechst images imply high seeding efficiencies, seeding efficiency could theoretically be overestimated by this indirect strategy as MSCs might have attached to the conical tube or have clumped together. 32 Group sizes were limited due to the costs associated with the use of the various products. Another limitation is that we did not test our chimeric cell/graft models yet in animal models. Despite the limitations, this study is a preliminary but essential step towards considering the use of dynamic seeding in a clinical setting. This study clearly demonstrates that MSCs can be seeded on the Avance® Nerve Graft and the NeuraGen® Nerve Guide. MSCs more efficiently adhered to the inner and outer surface of the NeuraGen® Nerve Guide than to the Avance® Nerve Graft, MSCs are evenly distributed on the surface and do not migrate into the nerve or substrate. CONCLUSION The NeuraGen® Nerve Guide and the Avance® Nerve Graft do not negatively influence the viability of human MSCs. After 12 hours of dynamic seeding, 66% (Avance) to 94% (NeuraGen) of the administered dose of MSCs adhered to the nerve substitutes, with a statistically significant higher efficiency for the NeuraGen Nerve Guide. The vast majority of adhered MSCs survived and were distributed in a uniform manner among the surface of both nerve substitutes and did not migrate into the nerve or collagen material. Future human or animal studies will permit determination of the effects of MSCs seeded on nerve graft substitutes on motor regeneration or sensory re-innervation in large nerve deficits. Conflicts of interest The authors have nothing to disclose. This study was funded by the NIH R01, ‘Bridging the gap: angiogenesis and stem cell seeding of processed nerve allograft’. 1 RO1 NS102360-01A1 The Avance® Nerve Grafts used in this study were provided by AxoGen Inc., Alachua, Florida, USA. The NeuraGen® Nerve Guides used in this study were provided by Integra LifeSciences Holdings Corporation, Plainsboro, New Jersey, USA.