Nerve Allotransplantation for Traumatic Nerve Injury

周围神经的损伤会导致严重的永久性功能缺陷。同种异体神经移植提供了 无限来源的神经移植材料，临床上用于重建严重的，否则无法修复的 创伤性神经损伤。FK506可促进神经再生，是治疗以下疾病的首选免疫抑制剂 防止同种异体移植排斥反应，但可能导致显著的患者发病率。这样做的长期目标是 建议开发预防同种异体神经移植排斥反应的策略，同时最大限度地减少 免疫抑制，从而提高了安全性，拓宽了周围神经的临床适应证 同种异体移植。共刺激阻断诱导的供体特异性免疫无反应 在几种动物模型中显示允许通过同种异体移植再生神经，同时保持全身 免疫能力。同样地，同种异体神经移植物也可以冷藏以降低抗原性并种植。 与宿主雪旺细胞共同促进神经再生。加深对同种异体神经移植的认识 反应、冷保存效果和雪旺细胞迁移到神经移植物中提供了基础 将宿主免疫抑制需求降至最低的策略。同种异体神经移植的补充 改良的宿主雪旺细胞可通过同种异体神经移植促进再生。这些方法将 扩大同种异体神经移植的适应症，包括自体神经移植的较轻损伤 当前使用的。在目标1a中，同种异体抗原的直接和间接途径的相对贡献 同种异体周围神经移植中的表达以CD4+和CD8+基因敲除和MHC分类为特征 L1缺陷小鼠。目的1b研究冷保存同种异体神经移植对上述通路的影响。 STAT4和STAT6基因敲除小鼠。在目标2a中，评估了同种异体神经移植的再生。 同时阻断CD28/B7和CD40共刺激通路。在目标2b中，同种异体神经移植 冷保存，以优化共刺激阻断的效果，以允许同种异体移植接受。在AIM 3A，Thy1-CFP/S100-GFP小鼠用于研究雪旺细胞的迁移、分化和 冷冻保存的同种异体神经移植后的成熟度。在Aim 3b中，同种异体神经移植是冷保存的。 7周，然后接种过表达GDNF的培养的自体雪旺细胞 在没有任何免疫抑制的情况下通过同种异体神经移植进行再生。在Aim 3c中，同样的结构是 在长时间的猪同种异体移植模型中进行评估，该模型与遇到的长时间神经缺损非常相似 临床上，并将允许翻译到神经损伤的患者。

Injury to peripheral nerves can result in significant and permanent functional deficits. Nerve allografts offer a limitless source of nerve graft material that is used clinically to reconstruct severe otherwise irreparable traumatic nerve injuries. FK506 enhances nerve regeneration and is the immunosuppressant of choice for preventing allograft rejection, but can cause significant patient morbidity. The long-term objective of this proposal is to develop strategies to prevent nerve allograft rejection while minimizing the side effects of immunosuppression, thereby improving safety and broadening the clinical indications for peripheral nerve allotransplantation. Donor-specific immune unresponsiveness induced by costimulation blockade has been shown to permit nerve regeneration through allografts in several animal models while maintaining general immunocompetence. Similarly nerve allografts can be cold preserved to decrease antigenicity and seeded with host Schwann cells to facilitate nerve regeneration. A better understanding of the nerve allograft response, the effects of cold preservation, and Schwann cell migration into nerve grafts provides a basis for strategies to minimize requirements for host immunosuppression. Supplementation of nerve allografts with modified host Schwann cells may enhance regeneration through nerve allografts. These approaches will expand the indications for nerve allotransplantation to include less severe injuries where nerve autografts are currently used. In aim 1 a the relative contributions of the direct and indirect pathways of alloantigen presentation in peripheral nerve allografts are characterized using CD4+ and CD8+ knockout and MHC class ll-deficient mice. Aim 1b studies the effects of cold preservation of nerve allografts on these pathways using STAT4 and STAT6 gene knockout mice. In aim 2a, regeneration through nerve allografts is evaluated following simultaneous blockade of CD28/B7 and CD40 costimulatory pathways. In aim 2b, nerve allografts are cold preserved to optimize the efficacy of costimulatory blockade to permit allograft acceptance. In aim 3a, Thy1-CFP/S100-GFP mice are used to characterize Schwann cell migration, differentiation, and maturation when repopulating a cold preserved nerve allograft. In aim 3b, nerve allografts are cold preserved for 7 weeks and then seeded with cultured autologous Schwann cells that overexpress GDNF to permit regeneration through nerve allografts without any immunosuppression. In aim 3c this same construct is evaluated in a long swine allograft model that closely resembles the long nerve defects encountered clinically and will allow translation to the nerve-injured patient.