The human amniotic membrane (hAM) is an attractive biomaterial for regenerative medicine, as it contains amniotic mesenchymal stromal cells (hAMSC), epithelial cells (hAEC) and growth factors. We examined the potential use of hAM in orthopaedic and maxillofacial bone surgery, integrating the requirements of current regulations regarding advanced therapy medicinal products (ATMP) in the European Union. Previous studies have described the potential osteodifferentiation of intact hAM during whole-tissue culture in osteogenic conditions. The present study aims to determine whether in vitro osteodifferentiation of hAM is needed in the context bone repair, and the influence of this process on tissue structure, cell phenotype and cell function. Different conditions (fresh or cultured hAM; intact or hAM-derived cells) were tested. Phenotypic and functional analyses were performed with standard approaches (cell culture and staining, histological and immunolabelling) as well as original approaches (tissue staining, energy dispersive X-ray and X-ray diffraction). In our study, non-osteodifferentiated hAM (i.e., fresh or native hAM) exhibited innate pre-osteoblastic potential. Osteodifferentiation of fresh hAM induced a change in tissue structure, cell phenotype and function. Therefore, we hypothesize that pre-osteodifferentiation may not be necessary, especially if it induces unwanted changes. To our surprise, in these osteogenic conditions, hAEC had a mesenchymal phenotype with osteocyte function, and even native synthesis of hydroxyapatite, focusing osteogenic potential mainly in this epithelial layer. In conclusion, in vitro osteodifferentiation by tissue culture does not appear to be necessary for hAM to be used as an innovative ATMP for bone repair.

中文翻译：

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完整的人羊膜的体外骨分化在骨修复的背景下是无益的。

人羊膜（hAM）是一种用于再生医学的有吸引力的生物材料，因为它包含羊膜间充质基质细胞（hAMSC），上皮细胞（hAEC）和生长因子。我们研究了hAM在整形外科和颌面部骨外科中的潜在用途，并结合了欧盟有关先进治疗药物（ATMP）的现行法规要求。先前的研究描述了成骨条件下完整组织培养过程中完整hAM的潜在骨分化。本研究旨在确定在骨修复环境中是否需要进行hAM的体外骨分化，以及该过程对组织结构，细胞表型和细胞功能的影响。测试了不同的条件（新鲜或培养的hAM；完整或hAM衍生的细胞）。使用标准方法（细胞培养和染色，组织学和免疫标记）以及原始方法（组织染色，能量色散X射线和X射线衍射）进行表型和功能分析。在我们的研究中，非骨分化的hAM（即新鲜的或天然的hAM）表现出先天的成骨前细胞的潜力。新鲜hAM的骨分化诱导了组织结构，细胞表型和功能的改变。因此，我们假设前骨分化可能不是必需的，特别是如果它诱导了不必要的变化。令我们惊讶的是，在这些成骨条件下，hAEC具有具有骨细胞功能的间充质表型，甚至是羟基磷灰石的天然合成，主要将成骨潜能集中在该上皮层上。结论，