Institute of Cell Biology, Histology, and Embryology, Medical University of Graz, Graz, Austria.
Stem Cells Dev. 2012 May 20;21(8):1309-20. doi: 10.1089/scd.2011.0223. Epub 2011 Sep 6.
Mesenchymal stromal cells derived from the human amnion (hAMSC) currently play an important role in stem cell research, as they are multipotent cells that can be isolated using noninvasive methods and are immunologically tolerated in vivo. The objective of this study was to evaluate their endothelial differentiation potential with regard to a possible therapeutic use in vascular diseases. hAMSC were isolated from human term placentas and cultured in Dulbecco's modified Eagle's medium (DMEM) (non-induced hAMSC) or endothelial growth medium (EGM-2) (induced hAMSC). Induced hAMSC changed their fibroblast-like toward an endothelial-like morphology, and were able to take up acetylated low-density lipoprotein and form endothelial-like networks in the Matrigel assay. However, they did not express the mature endothelial cell markers von Willebrand factor and vascular endothelial-cadherin. Gene expression analysis revealed that induced hAMSC significantly downregulated pro-angiogenic genes such as tenascin C, Tie-2, vascular endothelial growth factor A (VEGF-A), CD146, and fibroblast growth factor 2 (FGF-2), whereas they significantly upregulated anti-angiogenic genes such as serpinF1, sprouty1, and angioarrestin. Analysis of protein expression confirmed the downregulation of FGF-2 and Tie-2 (27%±8% and 13%±1% of non-induced cells, respectively) and upregulation of the anti-angiogenic protein endostatin (226%±4%). Conditioned media collected from hAMSC enhanced viability of endothelial cells and had a stabilizing effect on endothelial network formation as shown by lactate dehydrogenase and Matrigel assay, respectively. In summary, endothelial induced hAMSC acquired some angiogenic properties but resisted undergoing a complete differentiation into mature endothelial cells by upregulation of anti-angiogenic factors. Nevertheless, they had a survival-enhancing effect on endothelial cells that might be useful in a variety of cell therapy or tissue-engineering approaches.
人羊膜间充质干细胞（hAMSC）目前在干细胞研究中发挥着重要作用，因为它们是多能细胞，可以通过非侵入性方法分离，并且在体内具有免疫耐受性。本研究旨在评估其内皮细胞分化潜能，以期在血管疾病的治疗中得到应用。hAMSC 从人足月胎盘分离出来，在 Dulbecco 改良 Eagle 培养基（DMEM）中培养（未诱导的 hAMSC）或内皮细胞生长培养基（EGM-2）中培养（诱导的 hAMSC）。诱导的 hAMSC 改变了其成纤维细胞样形态，向内皮样形态转变，并能够摄取乙酰化低密度脂蛋白，并在 Matrigel 测定中形成内皮样网络。然而，它们并不表达成熟的内皮细胞标志物 von Willebrand 因子和血管内皮钙黏蛋白。基因表达分析显示，诱导的 hAMSC 显著下调了促血管生成基因，如 tenascin C、Tie-2、血管内皮生长因子 A（VEGF-A）、CD146 和成纤维细胞生长因子 2（FGF-2），而显著上调了抗血管生成基因，如 serpinF1、sprouty1 和 angioarrestin。蛋白表达分析证实了 FGF-2 和 Tie-2 的下调（分别为非诱导细胞的 27%±8%和 13%±1%）和抗血管生成蛋白 endostatin 的上调（226%±4%）。hAMSC 收集的条件培养基提高了内皮细胞的活力，并通过乳酸脱氢酶和 Matrigel 测定分别对内皮网络形成具有稳定作用。总之，诱导的 hAMSC 获得了一些血管生成特性，但通过上调抗血管生成因子，抵抗完全分化为成熟的内皮细胞。然而，它们对内皮细胞具有增强生存的作用，这在各种细胞治疗或组织工程方法中可能是有用的。
