Self-organized vascular networks from human pluripotent stem cells in a synthetic matrix

Abstract

The success of tissue regenerative therapies is contingent on functional and multicellular vasculature within the redeveloping tissue. Although endothelial cells (ECs), which compose the vasculature's inner lining, are intrinsically able to form nascent networks, these structures regress without the recruitment of pericytes, supporting cells that surround microvessel endothelium. Reconstruction of typical in vivo microvascular architecture traditionally has been done using distinct cell sources of ECs and pericytes within naturally occurring matrices; however, the limited sources of clinically relevant human cells and the inherent chemical and physical properties of natural materials hamper the translational potential of these approaches. Here we derived a bicellular vascular population from human pluripotent stem cells (hPSCs) that undergoes morphogenesis and assembly in a synthetic matrix. We found that hPSCs can be induced to codifferentiate into early vascular cells (EVCs) in a clinically relevant strategy amenable to multiple hPSC lines. These EVCs can mature into ECs and pericytes, and can self-organize to form microvascular networks in an engineered matrix. These engineered human vascular networks survive implantation, integrate with the host vasculature, and establish blood flow. This integrated approach, in which a derived bicellular population is exploited for its intrinsic self-assembly capability to create microvasculature in a deliverable matrix, has vast ramifications for vascular construction and regenerative medicine.codifferentiation | hydrogels

Harnessing developmental processes for vascular engineering and regeneration

“…Whereas the cell types that form the vasculature in vivo are limited to ECs and mural cells, approaches to generate de novo human vasculature have used a much wider variety of cell types (see Table 1). These include primary ECs (Baranski et al, 2013) and endothelial progenitor cells (EPCs) as cell sources for the vessel inner lining, as well as mesenchymal stem cells (MSCs) (Stratman and Davis, 2012) and pluripotent stem cells (PSCs) (Kusuma et al, 2013;Samuel et al, 2013), which have a wider lineage potential. Primary ECs can be derived from various tissues, including umbilical cord blood vessels, the dermal vasculature, the lungs and the pulmonary artery.…”

“…Ideally, vasculature would be created from only a single progenitor cell that gives rise to both cell types needed. Recently, we characterized a unique bipotential cell population derived from human PSCs (hPSCs) called early vascular cells (EVCs) that can differentiate into both ECs and perivascular cells, which then self-organize into microvascular networks within an engineered matrix (Kusuma et al, 2013). The ability to generate both ECs and perivascular cells from a single vascular progenitor population may help to reduce the time, effort and cost of vascular differentiation protocols, as well as to generate more stable engineered vasculature.…”

“…Integrin-mediated cell adhesion, (Hodivala-Dilke, 2008;Desgrosellier and Cheresh, 2010), matrix metalloproteinase (MMPs)-mediated matrix remodeling (Iruela-Arispe and Davis, 2009;Stratman et al, 2009;Hanjaya-Putra et al, 2011) and matrix stiffness (Sieminski et al, 2007;Moon et al, 2010;Hanjaya-Putra et al, 2012) have been implicated as key parameters supporting vascular development, including vascular morphogenesis, differentiation and network formation. We and others have demonstrated that incorporating an integrin-binding peptide [Arg-Gly-Asp (RGD)] within the synthetic matrix promotes vascular lumen and capillary formation via integrinmediated cell adhesion and morphogenesis (Moon et al, 2010;Hanjaya-Putra et al, 2011;Kusuma et al, 2013). In addition, Davis and collaborators reported that a specific MMP, membrane-type 1 MMP (MT1-MMP), plays a crucial role in the formation of lumens and the network formation of ECs within the 3D HA and collagen matrix (Stratman et al, 2009;Hanjaya-Putra et al, 2011).…”

“…The current state-of-the-art technology in engineering and cellular therapies allow an unprecedented level of control over the patient specificity of vascular therapeutics (Sun et al, 2011;Chen et al, 2012;Cuchiara et al, 2012;Kusuma et al, 2013). Tailor-made biomaterials and patient-specific stem cells are only part of the promise held by regenerative medicine, but whereas advanced engineering approaches can provide effective therapies and implantable vasculatures, obstacles Box 1.…”

Human induced pluripotent stem cells derived endothelial cells mimicking vascular inflammatory response under flow

“…6,7 Due to their capacity for long-term self-renewal and multipotent differentiation, human iPSCs are highly promising cell sources for a wide range of biomedical applications, including disease mechanism research, tissue/organ engineering, cellular replacement therapies, and pharmacology and toxicology screening. [8][9][10] The capacity of hiPSCs to differentiate into particular cellular lineages is undergoing intensive study. Recently, hiPSCs have been differentiated into cardiomyocytes, pancreatic b-like cells, endothelial cells, and other cell types.…”