Biedermann Thomas, Böttcher-Haberzeth Sophie, Klar Agnieszka S, Pontiggia Luca, Schiestl Clemens, Meuli-Simmen Claudia, Reichmann Ernst, Meuli Martin
Tissue Biology Research Unit, University Children's Hospital Zurich, Zurich, Switzerland.
Pediatr Surg Int. 2013 Jan;29(1):71-8. doi: 10.1007/s00383-012-3208-1.
Tissue engineered skin substitutes are a promising tool to cover large skin defects, but little is known about reinnervation of transplants. In this experimental study, we analyzed the ingrowth of host peripheral nerve fibers into human tissue engineered dermo-epidermal skin substitutes in a rat model. Using varying cell types in the epidermal compartment, we wanted to assess the influence of epidermal cell types on reinnervation of the substitute.
We isolated keratinocytes, melanocytes, fibroblasts, and eccrine sweat gland cells from human skin biopsies. After expansion, epidermal cells were seeded on human dermal fibroblast-containing collagen type I hydrogels as follows: (1) keratinocytes only, (2) keratinocytes with melanocytes, (3) sweat gland cells. These substitutes were transplanted into full-thickness skin wounds on the back of immuno-incompetent rats and were analyzed after 3 and 8 weeks. Histological sections were examined with regard to myelinated and unmyelinated nerve fiber ingrowth using markers such as PGP9.5, NF-200, and NF-145.
After 3 weeks, the skin substitutes of all three epidermal cell variants showed no neuronal ingrowth from the host into the transplant. After 8 weeks, we could detect an innervation of all three types of skin substitutes. However, the nerve fibers were restricted to the dermal compartment and we could not find any unmyelinated fibers in the epidermis. Furthermore, there was no distinct difference between the constructs resulting from the different cell types used to generate an epidermis.
Our human tissue engineered dermo-epidermal skin substitutes demonstrate a host-derived innervation of the dermal compartment as early as 8 weeks after transplantation. Thus, our substitutes apparently have the capacity to attract nerve fibers from adjacent host tissues, which also grow into grafts and thereby potentially restore skin sensitivity.
组织工程皮肤替代物是覆盖大面积皮肤缺损的一种有前景的工具，但对于移植后的再神经支配了解甚少。在本实验研究中，我们在大鼠模型中分析了宿主周围神经纤维向人组织工程真皮 - 表皮皮肤替代物的长入情况。通过在表皮层使用不同的细胞类型，我们想要评估表皮细胞类型对替代物再神经支配的影响。
我们从人皮肤活检组织中分离出角质形成细胞、黑素细胞、成纤维细胞和小汗腺细胞。扩增后，将表皮细胞接种到含有人真皮成纤维细胞的I型胶原水凝胶上，如下：（1）仅角质形成细胞，（2）角质形成细胞与黑素细胞，（3）汗腺细胞。将这些替代物移植到免疫缺陷大鼠背部的全层皮肤伤口上，并在3周和8周后进行分析。使用PGP9.5、NF - 200和NF - 145等标记物对组织学切片进行有髓和无髓神经纤维长入情况的检查。
3周后，所有三种表皮细胞变体的皮肤替代物均未显示宿主神经纤维长入移植体。8周后，我们能够检测到所有三种类型的皮肤替代物均有神经支配。然而，神经纤维仅限于真皮层，在表皮中未发现任何无髓纤维。此外，用于生成表皮的不同细胞类型所产生的构建体之间没有明显差异。
我们的人组织工程真皮 - 表皮皮肤替代物在移植后8周就显示出宿主来源的真皮层神经支配。因此，我们的替代物显然有能力吸引来自相邻宿主组织的神经纤维，这些神经纤维也长入移植物，从而有可能恢复皮肤敏感性。
