Repairing Large Radial Nerve Defects by Acellular Nerve Allografts Seeded with Autologous Bone Marrow Stromal Cells in a Monkey Model

In this study, we aimed to evaluate the potential of tissue-engineered nerve grafts created from acellular allogenic nerve tissues combined with autologous bone marrow stromal cells (BMSCs) for repairing large peripheral nerve lesions. In a rhesus monkey model, a 2.5-cm-long gap was created in the radial nerve, followed by implantation of either autografts or acellular allografts seeded with autologous BMSCs, Schwann cells (SCs), or no cells. Five months after surgery nerve regeneration was assessed functionally, electrophysiologically, and histomorphometrically. Compared to non-cell-laden allografts, BMSC-laden allografts remarkably facilitated the recovery of the grasping functions of the animals. This functional improvement was coupled with increased nerve conduction velocities and peak amplitudes of compound motor action potentials, and greater axon growth, as well as higher target muscle weight. Moreover, the intensities of nerve regeneration in the BMSC-laden group were comparable to those achieved with SC-laden allografts and autografts. Our data highlight the potential of BMSC-seed allografts for the repair of long peripheral nerve lesions, and reveal comparable regeneration intensities achieved by BMSC-, and SC-laden allografts, as well as autografts. Given their wide availability, BMSCs may represent a promising cell source for tissue-engineered nerve grafts.