Impact Of Endothelial Cells Research Articles

Impact of endothelial cells on the engineered liver recellularized with primary rat hepatocytes

Impact of endothelial cells on the engineered liver recellularized with primary rat hepatocytes

An endothelialized urothelial cell-seeded tubular graft for urethral replacement.

Many efforts are used to improve surgical techniques and graft materials for urethral reconstruction. We developed an endothelialized tubular structure for urethral reconstruction. Two tubular models were created in vitro. Human fibroblasts were cultured for 4 weeks to form fibroblast sheets. Then, endothelial cells (ECs) were seeded on the fibroblast sheets and wrapped around a tubular support to form a cylinder for the endothelialized tubular urethral model (ET). No ECs were added in the standard tubular model (T). After 21 days of maturation, urothelial cells were seeded into the lumen of both models. Constructs were placed under perfusion in a bioreactor for 1 week. At several times, histology and immunohistochemistry were performed on grafted nude mice to evaluate the impact of ECs on vascularization. Both models produced an extracellular matrix, without exogenous material, and developed a pseudostratified urothelium. Seven days after the graft, mouse red blood cells were present only in the outer layers in T model, but in the full thickness of ET model. After 14 days, erythrocytes were present in both models, but in a greater proportion in ET model. At day 28, both models were well-vascularized, with capillary-like structures in the whole thickness of the tubes. Incorporating endothelial cells was associated with an earlier vascularization of the grafts, which could decrease the necrosis of the transplanted tissue. As those models can be elaborated with the patient's cells, this tubular urethral graft would be unique in its autologous property.

Impact of Endothelial Cells on 3D Cultured Smooth Muscle Cells in a Biomimetic Hydrogel

For the development of vascular tissue engineering, the impact of endothelial cells (ECs) on smooth muscle cell (SMC) spreading, proliferation, and differentiation is explored in the current study using a coculture model. In this coculture model, SMCs were encapsulated in a biomimetic hydrogel based on methacrylated dextran-graft-lysine (Dex-MA-LA) and methacrylamide-modified gelatin (Gel-MA), and exposed to a monolayer of ECs. With EC coculture, SMC proliferation in 3D hydrogel was promoted at initial period, and the formation of denser cellular networks was enhanced. ECs dynamically modulated SMC phenotype by promoting a more contractile SMC phenotype initially (on day 2), indicated by the upregulated expression of contractile genes α-actin, calponin, smooth muscle-myosin heavy chain (SM-MHC), and smoothelin; however, the onset of maximum expressions was delayed by ECs. Full differentiation of SMCs was not obtained even with EC coculture. Higher level of platelet-derived growth factor (PDGF)-BB and latent transforming growth factor (TGF)-β1 were detected in medium of coculture. These biochemical cues together with the physical cue of tensional force within cellular networks may be responsible for the dynamic modulation of SMC phenotype in coculture. Synthesis of elastin was promoted by ECs at transcriptional level. The formation of denser cellular networks and synthesis of elastin suggest that coculture with ECs is a potential method to construct functional vessel media layer in vitro.

Impact of Endothelial Cells and Mechanical Conditioning on Smooth Muscle Cell Extracellular Matrix Production and Differentiation

The aim of the current study was to explore the separate and coupled effects of endothelial cell (EC) presence and mechanical conditioning on smooth muscle cell (SMC) responses by combining bilayered poly(ethylene glycol) diacrylate (PEGDA) hydrogels with a pulsatile flow bioreactor. Each construct was composed of an outer PEGDA layer containing SMC and an inner PEGDA layer, either with or without EC. After an initial 3 days of static culture, EC(+) and EC(-) constructs were each further divided into two subgroups, half of which received mechanical conditioning mimetic of late gestation (mean pressures of approximately 50 mmHg and peak-to-trough pressure differentials of approximately 20 mmHg at approximately 140-180 beats/min) and half of which were cultured statically. After 18 additional days of culture, the SMC-containing layer of each construct was harvested, and western blots and quantitative histology were conducted to compare collagen type I, collagen type III, and elastin levels among treatment groups. SMC differentiation was evaluated by focusing on SMC marker calponin h1 and direct regulators of its gene expression-the transcription factor serum response factor (SRF) and two of its binding partners, myocardin and Elk-1. Combined EC and pulsatile flow conditioning increased elastin production, but decreased collagen type I deposition. Further, combined EC presence and mechanical stimulation increased SRF levels and the ratio of myocardin to active, phosphorylated Elk-1. This modulation of SRF and its binding partners appeared to result in a net increase in SMC differentiation, as evidenced by an associated increase in calponin h1 levels.