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Objective To investigate the effect of brain microvascular endothelial cells (BMECs) on mesenchymal stem cells (MSCs) expressing fetal liver kinase-1(Flk-1) and von Willebrand factor (vWF) under normal and hypoxic conditions. Methods Human bone marrow MSCs and rat BMECs were isolated, cultured and identified. We used direct and indirect co-culture to induce the differentiation of MSCs. The expression of Flk-1 and vWF after induction was observed and analyzed by flow cytometry and immunofluorescence staining. Results Undifferentiated MSCs did not express Flk-1 or vWF. In indirect co-culture group, indirect co-culture under hypoxic conditions induced (7.58?0.58)% (n=6, P=0.034) MSCs to express Flk-1 but not vWF, while in normoxic indirect co-culture, MSCs expressed neither. In direct co-culture group, after 5-day direct co-culture with BMECs under normoxia or hypoxia, MSCs expressing Flk-1 accounted for (13.76?1.67)% (n=6, P
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AIM:To investigate the paracrine actions of mesenchymal stem cells(MSCs)to brain microvascular endothelial cells(BMECs)in hypoxic conditions.METHODS:Human bone marrow MSCs and rat BMECs were isolated,cultured and identified.The contents of VEGF and MMP-9 were confirmed using ELISA assays of the conditioned media.The transendothelial electrical resistance(TEER)was detected to reflect the permeability of the BMECs monolayer.The effects of different conditioned media on BMECs were investigated in hypoxic conditions.RESULTS:The contents of VEGF and MMP-9 in conditioned media were induced to increase significantly by the hypoxic stress,which were much lower in BMECs conditioned media than that in MSCs conditioned media.Hypoxia induced a significant increase in VEGF and MMP-9 in MSCs conditioned media collected in comparison to those in normal conditions.In hypoxic conditions,MSCs conditioned media enhanced the proliferation(optical density values:0.947?0.103 vs 0.254?0.024,P