Yamaguchi Yuji, Hearing Vincent J, Itami Satoshi, Yoshikawa Kunihiko, Katayama Ichiro
Department of Dermatology, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita-shi, Osaka 565-0871, Japan.
J Dermatol Sci. 2005 Oct;40(1):1-9. doi: 10.1016/j.jdermsci.2005.04.006.
Since trunk skin (or non-palmoplantar skin) is less durable under mechanical stress than sole skin (palm, plantar or palmoplantar skin), conventional trunk-derived skin grafts (including the trunk dermis) commonly result in erosion and ulceration when transplanted on to plantar wounds caused by various injuries including, diabetes mellitus or collagen diseases (including systemic sclerosis, polyarthritis nodosa and rheumatoid arthritis). However, trunk-derived epidermis can adopt a plantar phenotype, characterized by keratin 9 expression, hypopigmentation and thick suprabasal layers, through factors derived from plantar dermal fibroblasts in the wounds. Thus, intractable plantar wounds with exposed bones can be treated with the combination of bone marrow exposure, occlusive dressing and epidermal grafting. The higher expression of dickkopf 1 (DKK1), an inhibitor of canonical Wnt/beta-catenin signals, in the plantar dermis partly explains these phenomena. Thus, mesenchymal-epithelial interactions play important roles not only in embryogenesis (the embryonic development) but also in maintaining the homeostasis of adult tissue. The topographical (site-specific) interactions of growth factors and substances, including DKKs, fibroblast growth factors (FGFs) and transforming growth factor-beta (TGF-beta) family proteins including bone morphogenetic proteins (BMPs), may explain the site-specific differences in the skin in addition to the expression patterns of HOX genes and sonic hedgehogs (Shhs). We review the importance of dermal-epidermal interactions in tissue homeostasis and regeneration, especially in palms and soles.
由于躯干皮肤（或非掌跖皮肤）在机械应力下的耐久性低于足底皮肤（手掌、足底或掌跖皮肤），传统的源自躯干的皮肤移植（包括躯干真皮）在移植到由各种损伤（包括糖尿病或胶原疾病，如系统性硬化症、结节性多关节炎和类风湿性关节炎）引起的足底伤口上时，通常会导致糜烂和溃疡。然而，源自躯干的表皮可以通过伤口中足底真皮成纤维细胞衍生的因子，呈现出足底表型，其特征为角蛋白9表达、色素减退和基底层上的增厚层。因此，对于伴有骨质外露的难治性足底伤口，可采用骨髓暴露、封闭敷料和表皮移植相结合的方法进行治疗。典型Wnt/β-连环蛋白信号抑制剂Dickkopf 1（DKK1）在足底真皮中的高表达部分解释了这些现象。因此，间充质-上皮相互作用不仅在胚胎发生（胚胎发育）中起重要作用，而且在维持成年组织的稳态中也起重要作用。生长因子和物质（包括DKK、成纤维细胞生长因子（FGF）以及包括骨形态发生蛋白（BMP）在内的转化生长因子-β（TGF-β）家族蛋白）的拓扑学（位点特异性）相互作用，除了HOX基因和音猬因子（Shh）的表达模式外，可能还解释了皮肤的位点特异性差异。我们综述了真皮-表皮相互作用在组织稳态和再生中的重要性，特别是在手掌和足底。
