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Abstract Vascular tissue engineering is a promising approach for regenerating damaged blood vessels and developing new therapeutic approaches for heart disease treatment. To date, different sources of cells have been recognized that offer assistance within the recovery of heart supply routes and veins with distinctive capacities and are compelling for heart regeneration. However, some challenges still remain that need to be overcome to establish the full potential application of these cells. In this paper, we review the different cell sources used for vascular tissue engineering, focusing on extraembryonic tissue-derived cells (ESCs), and elucidate their roles in cardiovascular disease. In addition, we highlight the intricate interplay between mechanical and biochemical factors in regulating mesenchymal stem cell (MSC) differentiation, offering insights into optimizing their application in vascular tissues.

Vascular tissue engineering is a promising approach for regenerating damaged blood vessels and developing new therapeutic approaches for heart disease treatment. To date, different sources of cells have been recognized that offer assistance within the recovery of heart supply routes and veins with distinctive capacities and are compelling for heart regeneration. However, some challenges still remain that need to be overcome to establish the full potential application of these cells. In this paper, we review the different cell sources used for vascular tissue engineering, focusing on extraembryonic tissue-derived cells (ESCs), and elucidate their roles in cardiovascular disease. In addition, we highlight the intricate interplay between mechanical and biochemical factors in regulating mesenchymal stem cell (MSC) differentiation, offering insights into optimizing their application in vascular tissues. [ABSTRACT FROM AUTHOR]

Summary: Tissue regeneration upon wounding in plants highlights the developmental plasticity of plants. Previous studies have described the morphological and molecular changes of secondary vascular tissue (SVT) regeneration after large‐scale bark girdling in trees. However, how phytohormones regulate SVT regeneration is still unknown.Here, we established a novel in vitro SVT regeneration system in the hybrid aspen (Populus tremula × Populus tremuloides) clone T89 to bypass the limitation of using field‐grown trees. The effects of phytohormones on SVT regeneration were investigated by applying exogenous hormones and utilizing various transgenic trees. Vascular tissue‐specific markers and hormonal response factors were also examined during SVT regeneration.Using this in vitro regeneration system, we demonstrated that auxin and cytokinin differentially regulate phloem and cambium regeneration. Whereas auxin is sufficient to induce regeneration of phloem prior to continuous cambium restoration, cytokinin only promotes the formation of new phloem, not cambium. The positive role of cytokinin on phloem regeneration was further confirmed in cytokinin overexpression trees. Analysis of a DR5 reporter transgenic line further suggested that cytokinin blocks the re‐establishment of auxin gradients, which is required for the cambium formation. Investigation on the auxin and cytokinin signalling genes indicated these two hormones interact to regulate SVT regeneration.Taken together, the in vitro SVT regeneration system allows us to make use of various molecular and genetic tools to investigate SVT regeneration. Our results confirmed that complementary auxin and cytokinin domains are required for phloem and cambium reconstruction. [ABSTRACT FROM AUTHOR]

Due to the limited success rate of currently available vascular replacements, tissue engineering has received tremendous attention in recent years. A main challenge in the field of regenerative medicine is creating a mechanically functional tissue with a well‐organized extracellular matrix, particularly of collagen and elastin. In this study, the native collagen scaffold derived from decellularized tendon sections, as a scaffold having the potential to be used for vascular tissue engineering applications, was studied. We showed that the elasticity of the scaffolds was improved when crosslinked with the bovine elastin. The effect of different concentrations of elastin on mechanical properties of the collagen scaffolds was evaluated of which 15% elastin concentration was selected for further analysis based on the results. Addition of 15% elastin to collagen scaffolds significantly decreased Young's modulus and the tensile stress at the maximum load and increased the tensile strain at the maximum load of the constructs as compared to those of the collagen scaffolds or control samples. Moreover, tubular elastin modified collagen scaffolds showed significantly higher burst pressure compared to the control samples. Smooth muscle cells and endothelial cells cultured on the elastin modified collagen scaffolds showed high viability (>80%) after 1, 3, and 7 days. Furthermore, the cells showed a high tendency to align with the collagen fibers within the scaffold and produced their own extracellular matrix over time. In conclusion, the results show that the decellularized tendon sections have a great potential to be used as scaffolds for vascular tissue engineering applications. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1225–1234, 2019. [ABSTRACT FROM AUTHOR]

The vascular endothelium constitutes the inner lining of the blood vessel, and malfunction and injuries of the endothelium can cause cardiovascular diseases as well as other diseases including stroke, tumor growth, and chronic kidney failure. Generation of effective sources to replace injured endothelial cells (ECs) could have significant clinical impact, and somatic cell sources like peripheral or cord blood cannot credibly supply enough endothelial cell progenitors for multitude of treatments. Pluripotent stem cells are a promising source for a reliable EC supply, which have the potential to restore tissue function and treat vascular diseases. We have developed methods to differentiate induced pluripotent stem cells (iPSCs) efficiently and robustly across multiple iPSC lines into nontissue-specific pan vascular ECs (iECs) with high purity. These iECs present with canonical endothelial cell markers and exhibit measures of endothelial cell functionality with the uptake of Dil fluorescent dye-labeled acetylated low-density lipoprotein (Dil-Ac-LDL) and tube formation. Using proteomic analysis, we revealed that the iECs are more proteomically similar to established human umbilical vein ECs (HUVECs) than to iPSCs. Posttranslational modifications (PTMs) were most shared between HUVECs and iECs, and potential targets for increasing the proteomic similarity of iECs to HUVECs were identified. Here we demonstrate an efficient robust method to differentiate iPSCs into functional ECs, and for the first time provide a comprehensive protein expression profile of iECs, which indicates their similarities with a widely used immortalized HUVECs, allowing for further mechanistic studies of EC development, signaling, and metabolism for future regenerative applications. NEW & NOTEWORTHY We have developed methods to differentiate induced pluripotent stem cells (iPSCs) across multiple iPSC lines into nontissue-specific pan vascular ECs (iECs) and demonstrated the proteomic similarity of these cells to a widely used endothelial cell line (HUVECs). We also identified posttranslational modifications and targets for increasing the proteomic similarity of iECs to HUVECs. In the future, iECs can be used to study EC development, signaling, and metabolism for future regenerative applications.

The Arg-Gly-Asp (RGD) sequence is one of the most effective cellular adhesion ligands and has been used to improve cellular activity of biomaterials for tissue regenerative medicine. The aim of this study was to develop new facile immobilization methods of RGD on electrospun polyurethane (PU) meshes, using tyrosinase (Ty), to promote attachment and proliferation of human umbilical vein endothelial cells (HUVECs). The RGD peptides were readily immobilized on PU substrates, for 1 h, using 0.4 kU/mL of Ty. Water contact angles and X-ray photoelectron spectroscopy (XPS) were used in order to verify that the RGD peptide was effectively conjugated onto the PU (0.120 nmol/mg-mesh); surface concentration was shown to be proportional to the peptide feed concentration. Enhanced HUVEC attachment onto the polymer substrate was observed after 1 day, and the immobilized RGD was clearly demonstrated to promote the proliferation and spreading of cells on the surface, indicating that the method developed for the conjugation of the peptides on the PU was efficient. These results suggest that this enzyme-triggered immobilization method for the cellular adhesion ligand, RGD, onto the PU mashes may be an efficient tool for improving the biological activity of substrates, especially for vascular tissue engineering. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

As a vascular scaffold, it should have proper mechanical property to match autologous tissue and resist the blood pressure. The development of a biomimetic surface with biomolecules which is able to mimic the anticoagulation properties is fundamental and difficult in the research for blood vessel substitutes to overcome the formation of thrombi. In the present research, heparin-grafted poly(ester-urethane)urea/gelatin (PU75-E/N-Hep) nanofibrous tubular scaffold was prepared via electrospinning technique followed by heparin grafting. The fabricated PU75-E/N-Hep nanofibrous tubular scaffold showed higher hydrophilicity, matched mechanical properties and improved blood compatibility. Furthermore, cell viability, cell morphology from cells culture in vitro and H&E staining, Masson's trichrome staining, immunohistochemistry staining, immunofluorescent staining were proceeded after implanted in rat's abdominal arterues for 1 week and 4 weeks, demonstrating that scaffold contributed to facilitating the migration and growth of smooth muscle cells as well as inducing rapid adhesion of endothelial cells. Hence, the PU75-E/N-Hep nanofibrous tubular scaffold is a promising candidate which can not only prevent acute thrombosis but also promote rapid regeneration of vascular tissue. • The scaffold could facilitate the migration and growth of smooth muscle cells and induce rapid adhesion of endothelial cells. [ABSTRACT FROM AUTHOR]