Toward anIn VitroVasculature: Differentiation of Mesenchymal Stromal Cells Within an Endothelial Cell-Seeded Modular Construct in a Microfluidic Flow Chamber

Abstract

An in vitro tissue construct amenable to perfusion was formed by randomly packing mesenchymal stromal cell (MSC)-embedded, endothelial cell (EC)-coated collagen cylinders (modules) into a microfluidic chamber. The interstices created by the random packing of the submillimeter-sized modules created EC-lined channels. Flow caused a greater than expected amount of contraction and remodeling in the modular constructs. Flow influenced the MSC to develop smooth muscle cell markers (smooth muscle actin-positive, desmin-positive, and von Willebrand factor-negative) and migrate toward the surface of the modules. When modules were coated with EC, the extent of MSC differentiation and migration increased, suggesting that the MSC were becoming smooth muscle cell-or pericyte-like in their location and phenotype. The MSC also proliferated, resulting in a substantial increase in the number of differentiated MSC. These effects were markedly less for static controls not experiencing flow. As the MSC migrated, they created new matrix that included the deposition of proteoglycans. Collectively, these results suggest that MSC-embedded modules may be useful for the formation of functional vasculature in tissue engineered constructs. Moreover, these flow-conditioned tissue engineered constructs may be of interest as three-dimensional cell-laden platforms for drug testing and biological assays.

Bone Marrow-Derived Mesenchymal Stromal Cells Enhance Chimeric Vessel Development Driven by Endothelial Cell-Coated Microtissues

“…The ability of bmMSCs, in the context of modules, to differentiate into a pericyte-like cell type has been confirmed by in vitro experiments, where bmMSCs become SMA and desmin positive in the presence of ECs when subject to flow in a microfluidic remodeling chamber. 43 These observations are consistent with other reports in which bmMSCs have also been shown to differentiate into both vWF + ECs and SMA + pericytes after implantation into a hind-leg ischemia model. 44 As it has become clear that bmMSCs and perhaps almost all MSCs are normally resident as pericytes before isolation, 12,13 it is perhaps not surprising that the bmMSCs express aspects of the pericyte phenotype upon implantation with vessel-forming ECs.…”

The role of mechanical stimuli in the vascular differentiation of mesenchymal stem cells

“…Tubular shear stress systems perfuse medium through a tubular scaffold, the inner layer of which is seeded with MSCs Dong et al, 2009;O'Cearbhaill et al, 2008). Microfluidic systems contain submillimeter-sized modules that are made out of gel, such as collagen, and filled with the cells of choice; these modules are then packed into a chamber with pillars to hold them in place, before the chamber is connected to a flow circuit to undergo fluid perfusion (Bruzewicz et al, 2008;Khan and Sefton, 2010;Khan et al, 2012).…”

Cotransplantation of Adipose-Derived Mesenchymal Stromal Cells and Endothelial Cells in a Modular Construct Drives Vascularization in SCID/bg Mice

“…n = 4 implants. Color images available online at www.liebertpub.com/tea considerable migration to a ''pericyte-like'' position and proliferation of the bmMSC in vitro 41 and in vivo 21 so that the direct cell contact emerges over time.…”