Mesenchymal Stem Cells Can Be Differentiated Into Endothelial Cells In Vitro

TLDR

Human bone marrow–derived mesenchymal stem cells can differentiate into osteocytes, chondrocytes, and adipocytes in vitro and in vivo. This study aimed to determine whether MSCs can be directed to an endothelial phenotype in vitro. MSCs were isolated from donor bone marrow mononuclear cells, characterized by flow cytometry, and induced to differentiate into endothelial‑like cells by culturing confluent cells with 2 % fetal calf serum and 50 ng ml⁻¹ VEGF, followed by functional angiogenesis assays. The differentiated cells expressed endothelial markers KDR, FLT‑1, and von Willebrand factor, formed capillary‑like structures in vitro, and thus demonstrate that adult MSCs can acquire phenotypic and functional endothelial characteristics, offering a basis for vascularized tissue engineering.

Abstract

Human bone marrow‐derived mesenchymal stem cells (MSCs) have the potential to differentiate into mesenchymal tissues like osteocytes, chondrocytes, and adipocytes in vivo and in vitro. The aim of this study was to investigate the in vitro differentiation of MSCs into cells of the endothelial lineage. MSCs were generated out of mononuclear bone marrow cells from healthy donors separated by density gradient centrifugation. Cells were characterized by flow cytometry using a panel of monoclonal antibodies and were tested for their potential to differentiate along different mesenchymal lineages. Isolated MSCs were positive for the markers CD105, CD73, CD166, CD90, and CD44 and negative for typical hematopoietic and endothelial markers. They were able to differentiate into adipocytes and osteocytes after cultivation in respective media. Differentiation into endothelial‐like cells was induced by cultivation of confluent cells in the presence of 2% fetal calf serum and 50 ng/ml vascular endothelial growth factor. Laser scanning cytometry analysis of the confluent cells in situ showed a strong increase of expression of endothelial‐specific markers like KDR and FLT‐1, and immunofluorescence analysis showed typical expression of the von Willebrand factor. The functional behavior of the differentiated cells was tested with an in vitro angiogenesis test kit where cells formed characteristic capillary‐like structures. We could show the differentiation of expanded adult human MSCs into cells with phenotypic and functional features of endothelial cells. These predifferentiated cells provide new options for engineering of artificial tissues based on autologous MSCs and vascularized engineered tissues.