Comparing Processed Nerve Allografts and Assessing Their Capacity to Retain and Release Nerve Growth Factor

Abstract

Peripheral nerve gap injuries continue to present a clinical challenge to today's surgeons. One method of surgical repair, implantation of acellular allografts, has been developed with the aim of bridging the gap with a cadaveric graft after removal of its cellular components, thereby accelerating axonal regeneration and eliminating the need for immunosuppression in recipient patients. Although decellularizing allografts reduces rates of graft rejection, the same chemical processing modifies the neural microenvironment, removing neutrotrophic factors and modifying the complex extracellular matrix. In this study, we explore 3 common methods for producing acellular allografts. Extracellular matrix content remaining after processing was investigated and was found to be highly dependent on the decellularization method. In addition, scanning electron micrographs were obtained to evaluate the structural effects of the decellularization methods. Though the content and structure of these processed allografts will contribute to their effectiveness as nerve gap repair candidates, we demonstrate that it also affects their capacity to be supplemented/preloaded with the prototypical neurotrophin, nerve growth factor (NGF), essential to neuronal regeneration. Although all allografts had some capacity for retaining NGF in the first 24 hours, only Sondell-processed grafts retained NGF over the entire experimental period of 21 days. Future studies will include validating these processed and supplemented allografts as viable alternatives to traditional autograft nerve gap repair.

End-to-side neurorrhaphy in the reconstruction of peripheral segmental neural loss: an experimental study

“…Advances in tissue engineering in the last decade have allowed the production of decellularized nerve allografts that, unlike conventional allografts, are depurated of their antigenic component, but which still maintain their three-dimensional structure of the nerve skeleton for axonal growth. Decellularized nerve allografts represent a promising alternative with the potential to be explored 9 , but they have an exorbitant cost 10 – 13 .…”