Shear stress magnitude is critical in regulating the differentiation of mesenchymal stem cells even with endothelial growth medium

摘要

Human mesenchymal stem cells (MSC) were seeded onto the inner surface of a tubular silicon construct and, after 24 h, were exposed to a shearing stress of either 2.5 or 10 dyne/cm2 for 1 day. The fluid contained endothelial growth factors in both cases. Morphological changes and cytoskeletal rearrangements were observed in the stimulated cells. Immunofluorescence staining showed that low (2.5 dyne/cm2) and high shear stress (10 dyne/cm2) resulted in the expression of von Willebrand factor (vWF) and calponin, respectively. At low shear stress, CD31 (PECAM-1) was significantly expressed whereas vWF and KDR expression was only slightly higher than those under 10 dyne/cm2. All three markers related to smooth muscle cells (myocardin, myosin heavy chain, and SM‐22α) had significantly higher expression under shear stress of 10 dyne/cm2 compared with a 2.5 dyne/cm2, even in endothelial growth medium. Shear stress plays a critical role in regulating MSC differentiation and must be considered for bioengineered blood vessels.