Shear Stress Induces Differentiation Of Bone Marrow Mesenchymal Stem Cells Into Endothelial Cells

AIM: To examine the effect of shear stress on the differentiation of bone marrowmesenchymal stem cells(MSCs). METHOD: The parallel plate flow chambersystem of shear stress was designed. MSCs were subjected to different levels ofshear stress, of 3,8,15 dyn/cm2 respectively, for 24 h. Cell shape and orientationwere observed at oh,24 h during shear stress. Indirect IF staining was employedto identify the endothelial cell-specific marker Von Willebrand factor (vWF). Thefunctional markers of mature endothelial cells were examined by the uptake ofDil labled acetylated low-density lipoproteins(Dil-Ac-LDL)and formation oftube-like structures. RESULTS: The parallel plate flow chamber is transparentand free of toxicity. Steady laminar flow can be formed when fluid is passingthrough the chamber. After subjection to shear stress for 24 h, MSCs tended to bea more rounder, polygon-like cell shape, and aligned parallel to the flow. MSCssubjected to shear stress of 3,8 dyn/cm2 were positive for vWF staining,indicating the endothelial phenotype, and also positive for the uptaking of Dil-Ac-LDL and the formation of tube-like structures,indicating the possession of mature endothelial function. While cells under shear stress of 15 dyn/cm2 were negativefor both the vWF staining and the uptaking of Dil-Ac-LDL, indicating the lack ofdifferentiation. CONCLUSIOCONCLUSION: The parallel plate flow chamber we created canbe adopted as an in vitro cell culture system to generate shear stress. Shear stresscan induces differentiation of bone marrow mesenchymal stem cells intoendothelial cells in a stress levels dependent way.