Mechanisms of vasculogenesis in 3D fibrin matrices mediated by the interaction of adipose-derived stem cells and endothelial cells

Abstract

Vascularization of tissue-engineered constructs is essential to provide sufficient nutrient supply and hemostasis after implantation into target sites. Co-cultures of adipose-derived stem cells (ASC) with outgrowth endothelial cells (OEC) in fibrin gels were shown to provide an effective possibility to induce vasculogenesis in vitro. However, the mechanisms of the interaction between these two cell types remain unclear so far. The aim of this study was to evaluate differences of direct and indirect stimulation of ASC-induced vasculogenesis, the influence of ASC on network stabilization and molecular mechanisms involved in vascular structure formation. Endothelial cells (EC) were embedded in fibrin gels either containing non-coated or ASC-coated microcarrier beads as well as ASC alone. Moreover, EC-seeded constructs incubated with ASC-conditioned medium were used in addition to constructs with ASC seeded on top. Vascular network formation was visualized by green fluorescent protein expressing cells or immunostaining for CD31 and quantified. RT-qPCR of cells derived from co-cultures in fibrin was performed to evaluate changes in the expression of EC marker genes during the first week of culture. Moreover, angiogenesis-related protein levels were measured by performing angiogenesis proteome profiler arrays. The results demonstrate that proximity of endothelial cells and ASC is required for network formation and ASC stabilize EC networks by developing pericyte characteristics. We further showed that ASC induce controlled vessel growth by secreting pro-angiogenic and regulatory proteins. This study reveals angiogenic protein profiles involved in EC/ASC interactions in fibrin matrices and confirms the usability of OEC/ASC co-cultures for autologous vascular tissue engineering.

Adipose derived stem cell transplantation is better than bone marrow mesenchymal stem cell transplantation in treating hindlimb ischemia in mice

“…AD-MSCs produce and secrete many angiogenic factors, such as VEGF (Lauvrud et al, 2016) and HGF (Suga et al, 2009 (Verseijden et al, 2010). ADMSCs can produce growth factors and cytokines such as HGF, TNF-alpha (Kachgal and Putnam, 2011), PD-ECGF, FGF-2, MMP-9, Ang-2, pentraxin-3 (Rohringer et al, 2014), collagen IV, and fibronectin (MerfeldClauss et al, 2010). AD-MSCs have also been shown to have a high proliferative potential than BM-MSCs (Li et al, 2015).…”

Adipose Tissue-Derived Stem Cells in Regenerative Medicine

“…Interestingly, ADSCs appear to be key regulators of new blood vessel formation and have been demonstrated to differentiate easily to endothelial cells and to form quickly and simply vessel-like structures in Matrigel® substrates with assumed endothelial function [40]. Moreover, in different studies, regarding for instance cardiac infarct treatment, epithelial regeneration or neural tissue healing, vessel formation has been observed after injection of ADSCs alone or in the combination with other cell types [61,62]. …”

Human adipose-derived stromal cells for the production of completely autologous self-assembled tissue-engineered vascular substitutes

“…Moreover, based on recent studies, the endothelialization of ASC-TEVS could have a beneficial side effect since ASC have been shown to differentiate along a smooth muscle lineage pathway upon EC contact [16,20]. This means that ASC-TEVS endothelialization could induce a myogenic differentiation of ASC located directly under the endothelium leading to the formation of a media-like layer.…”

“…Many studies have confirmed the adipose-derived stromal cells (ASC) potential for multilineage differentiation as well as their low immunogenicity [15][16][17][18][19]. More recently, ASC have also been investigated in the context of vascular tissue engineering [16,[20][21][22]. Indeed, given ASC's differentiation capabilities, they were evaluated both as an EC source to form an endothelium-like monolayer in grafts lumen; or as a SMC source to seed vascular scaffolds.…”