Development of fibroblast/endothelial cell‐seeded collagen scaffolds for in vitro prevascularization

Abstract

The development of vascularized scaffolds remains one of the major challenges in tissue engineering, and co-culturing with endothelial cells is known as one of the possible approaches for this purpose. In this approach, optimization of cell culture conditions, scaffolds, and fabrication techniques is needed to develop tissue equivalents that will enable in vitro formation of a capillary network. Prevascularized equivalents will be more physiologically comparable to the native tissues and potentially prevent insufficient vascularization after implantation. This study aimed to culture human umbilical vein endothelial cells (HUVECs), alone or in co-culture with fibroblasts, on collagen scaffolds prepared by simple fabrication approaches for in vitro prevascularization. Different concentrations and ratios of HUVECs and fibroblasts seeded on collagen gel and sponge scaffolds under several culture conditions were examined. Cell viability, scaffolds morphology, and structure were analyzed. Collagen gel scaffolds showed good cell proliferation and viability, with higher proliferation rates for cells cultured in a 2:1 (fibroblasts: HUVECs) ratio and kept in endothelial cell growth medium. However, these matrices were unable to support endothelial cell sprouting. Collagen sponges were highly porous and showed good cell viability. However, they became fragile over time in culture, and they still lack signs of vascularization. Collagen scaffolds were a good platform for cell growth and viability. However, under the experimental conditions of this study, the HUVEC/fibroblast-seeded scaffolds were not suitable platforms to generate in vitro prevascularized equivalents.Our findings will be a valuable starting point to optimize culture microenvironments and scaffolds during fabrication of prevascularized scaffolds.

Porous collagen scaffolds enable endothelial lumen formation in vitro under both static and dynamic growth conditions

“…These comprise an extracellular environment that enables not only the attachment but also the migration of the cells. 35 Moreover, the provision of cues to initiate the assembly of the cells into vessel-like structures should be ensured. Under physiological conditions, the extracellular matrix in most tissues is made up of collagen.…”

“…In order to initiate the self‐assembly of endothelial cells, they require optimal culturing conditions defined by specific biochemical and biophysical conditions. These comprise an extracellular environment that enables not only the attachment but also the migration of the cells 35 . Moreover, the provision of cues to initiate the assembly of the cells into vessel‐like structures should be ensured.…”

Fabricating Multiphasic Angiogenic Scaffolds Using Amyloid/Roxadustat-Assisted High-Temperature Protein Printing

“…Without digging into the mechanism in our previous study, we have already seen that with the coculture of two PDLF and HUVEC, the stability of HUVEC communities will be improved. 76 In this research, mechanistically, by comparison with HUVEC alone, the set of HUVEC +PDLF was studied in two soft and hard tissues. For the hydrogel part, Matrigel was considered as a control.…”

Tissue‐engineered tracheal implants: Advancements, challenges, and clinical considerations

“…Examples encompass patterned 2‐hydroxyethyl methacrylate hydrogels, closely mimicking the mechanical properties of native airway, 94 and type I collagen, hydrogels like fibrin and agarose, which have demonstrated efficacy in supporting the growth of cultured respiratory ciliated epithelium and vascular venation. 95 While the use of hydrogels as artificial prosthetics is presently constrained, preliminary investigations in line with graft requirements have yielded promising results. However, additional studies are imperative to evaluate the mechanical integrity and feasibility of tubular constructs based on hydrogels.…”