Highlights
- • We found that the mesenchymal stem cells can be isolated from the second trimester of human amniotic fluid by the adherence method, which is inexpensive and easy to perform. Additionally, the amniocentesis procedure has no problem about contamination.
- • We have demonstrated that the human amniotic fluid-derived mesenchymal stem cells (hAF-MSCs) exhibited typical MSCs characteristics including displaying the fibroblast-liked morphology and the expression of some MSCs markers (CD44, CD73, CD90 and HLA-ABC). Unexpectedly, the CD105 could not be detected from hAF-MSCs. This finding might be associated with the source of MSCs, gestational age and the donor’s heterogeneity. Notably, we have demonstrated that the hAFCs showed negative expression of CD117 and anti-human fibroblasts. The result indicated that hAFCs are mesenchymal stem cells that are distinguished from amniotic fluid stem cells and fibroblasts.
- • We found that hAF-MSCs have the potential to differentiate into endothelial-like cells in the presence of vascular endothelial growth factor (VEGF) only by expressing certain endothelial specific markers (von Willebrand Factor and Vascular endothelial growth factor receptor 2, CD31 or platelet endothelial cell adhesion molecule 1 (PECAM-1) and endothelial nitric oxide synthase. However, the detectable expression levels of the endothelial specific genes are lower than human umbilical vein endothelial cells (HUVECs).
Abstract
Endothelial dysfunction is a principle feature of vascular-related disease. Endothelial cells have been acquired for the purposes of the restoration of damaged tissue in therapeutic angiogenesis. However, their use is limited by expansion capacity and the small amount of cells that are obtained. Human amniotic fluid mesenchymal stem cells (hAF-MSCs) are considered an important source for vascular tissue engineering. In this study, hAF-MSCs were characterized and then induced in order to differentiate into the endothelial-like cells. Human amniotic fluid cells (hAFCs) were obtained from amniocentesis at the second trimester of gestation. The cells were characterized as mesenchymal stem cells by flow cytometry. The results showed that the cells were positive for mesenchymal stem cell markers CD44, CD73, CD90 and HLA-ABC, and negative for CD31, Amniotic fluid stem cells marker: CD117, anti-human fibroblasts, HLA-DR and hematopoietic differentiation markers CD34 and CD45. The hAF-MSCs were differentiated into endothelial cells under the induction of vascular endothelial growth factor (VEGF) and analyzed for the expression of the endothelial-specific markers and function. The expression of the endothelial-specific markers was determined by reverse transcriptase-quantitative PCR (RT-qPCR), while immunofluorescent analysis demonstrated that the induced hAF-MSCs expressed von Willebrand factor (vWF), vascular endothelial growth factor receptor 2 (VEGFR2), CD31 and endothelial nitric oxide synthase (eNOS). The network formation assay showed that the induced hAF-MSCs formed partial networks. All results indicated that hAF-MSCs have the potential to be differentiated into endothelial-like cells, while human amniotic fluid might be a suitable source of MSCs for vascularized tissue engineering.