Beyond organoids: In vitro vasculogenesis and angiogenesis using cells from mammals and zebrafish

Hydrogel/microcarrier cell scaffolds for rapid expansion of satellite cells from large yellow croakers: Differential analysis between 2D and 3D cell culture

Cell culture meat is based on the scaled-up expansion of seed cells. The biological differences between seed cells from large yellow croakers in the two-dimensional (2D) and three-dimensional (3D) culture systems have not been explored. Here, satellite cells (SCs) from large yellow croakers (Larimichthys crocea) were grown on cell climbing slices, hydrogels, and microcarriers for five days to analyze the biological differences of SCs on different cell scaffolds. The results exhibited that SCs had different cell morphologies in 2D and 3D cultures. Cell adhesion receptors (Itgb1andsdc4) and adhesion spot markervclof the 3D cultures were markedly expressed. Furthermore, myogenic decision markers (Pax7andmyod) were significantly enhanced. However, the expression of myogenic differentiation marker (desmin) was significantly increased in the microcarrier group. Combined with the transcriptome data, this suggests that cell adhesion of SCs in 3D culture was related to the integrin signaling pathway. In contrast, the slight spontaneous differentiation of SCs on microcarriers was associated with rapid cell proliferation. This study is the first to report the biological differences between SCs in 2D and 3D cultures, providing new perspectives for the rapid expansion of cell culture meat-seeded cells and the development of customized scaffolds.

Establishment of a 3D multicellular placental microtissues for investigating the effect of antidepressant vortioxetine

The placenta is a unique organ with an active metabolism and dynamically changing physiology throughout pregnancy. It is difficult to elucidate the structure of cell-cell and cell-extracellular matrix interactions of the placenta in in vivo studies due to interspecies differences and ethical constraints. In this study, human umbilical cord vein cells (HUVEC) and human placental choriocarcinoma cells (BeWo) were co-cultured for the first time to form spheroids (microtissues) on a three-dimensional (3D) Petri Dish® mold and compared with a traditional two-dimensional (2D) system. Vortioxetine is an antidepressant with a lack of literature on its use in pregnancy in established cultures, the toxicity of vortioxetine was studied to investigate the response of spheroids representing placental tissue. Spheroids were characterised by morphology and exposed to vortioxetine. Cell viability and barrier integrity were then measured. Intercellular junctions and the localisation of serotonin transporter (SERT) proteins were demonstrated by immunofluorescence (IF) staining in BeWo cells. Human chorionic gonadotropin (beta-hCG) hormone levels were also measured. In the 3D system, cell viability and hormone production were higher than in the 2D system. It was observed that the barrier structure was impaired, the structure of intracellular skeletal elements was altered and SERT expression decreased depending on vortioxetine exposure. These results demonstrate that the multicellular microtissue placenta model can be used to obtain results that more closely resemble in vivo toxicity studies of various xenobiotics than other 2D and mono-culture spheroid models in the literature. It also describes the use of 3D models for soft tissues other than the placenta.

Multi-biological functions of intermedin in diseases

Intermedin (IMD) is a member of the calcitonin gene-related peptide (CGRP)/calcitonin (CT) superfamily, and it is expressed extensively throughout the body. The typical receptors for IMD are complexes composed of calcitonin receptor-like receptor (CLR) and receptor activity-modifying protein (RAMP), which leads to a biased activation towards Gαs. As a diagnostic and prognostic biomarker, IMD regulates the initiation and metastasis of multiple tumors. Additionally, IMD functions as a proangiogenic factor that can restrain excessive vascular budding and facilitate the expansion of blood vessel lumen, ultimately resulting in the fusion of blood vessels. IMD has protective roles in various diseases, including ischemia-reperfusion injury, metabolic disease, cardiovascular diseases and inflammatory diseases. This review systematically elucidates IMD's expression, structure, related receptors and signal pathway, as well as its comprehensive functions in the context of acute kidney injury, obesity, diabetes, heart failure and sepsis. However, the precise formation process of IMD short peptides in vivo and their downstream signaling pathway have not been fully elucidated yet. Further in-depth studies are need to translate IMD research into clinical applications.

Tissue-like cultured fish fillets through a synthetic food pipeline

Tissue-like cultured meats of some livestock have successfully been established by different approaches. However, the production of a structure similar to fish fillets is still challenging. Here, we develop tissue-like cultured fish fillets by assembly of large yellow croaker muscle fibers and adipocytes with 3D-printed gel. Inhibition of Tgf-β and Notch signals significantly promoted myogenic differentiation of piscine satellite cells (PSCs). The mixture of fish gelatin and sodium alginate combined with a p53 inhibitor and a Yap activator supported PSC viability and proliferation. Based on the texture of fish muscle tissue, a 3D scaffold was constructed by gelatin-based gel mixed with PSCs. After proliferation and differentiation, the muscle scaffold was filled with cultured piscine adipocytes. Finally, tissue-like fish fillets with 20 × 12 × 4 mm were formed, consisting of 5.67 × 10⁷ muscles and 4.02 × 10⁷ adipocytes. The biomanufacture of tissue-like cultured fish fillet here could be a promising technology to customize meat production with high fidelity.

Physical and biological advances in endothelial cell-based engineered co-culture model systems

Scientific knowledge in the field of cell biology and mechanobiology heavily leans on cell-based in vitro experiments and models that favor the examination and comprehension of certain biological processes and occurrences across a variety of environments. Cell culture assays are an invaluable instrument for a vast spectrum of biomedical and biophysical investigations. The quality of experimental models in terms of simplicity, reproducibility, and combinability with other methods, and in particular the scale at which they depict cell fate in native tissues, is critical to advancing the knowledge of the comprehension of cell-cell and cell-matrix interactions in tissues and organs. Typically, in vitro models are centered on the experimental tinkering of mammalian cells, most often cultured as monolayers on planar, two-dimensional (2D) materials. Notwithstanding the significant advances and numerous findings that have been accomplished with flat biology models, their usefulness for generating further new biological understanding is constrained because the simple 2D setting does not reproduce the physiological response of cells in natural living tissues. In addition, the co-culture systems in a 2D stetting weakly mirror their natural environment of tissues and organs. Significant advances in 3D cell biology and matrix engineering have resulted in the creation and establishment of a new type of cell culture shapes that more accurately represents the in vivo microenvironment and allows cells and their interactions to be analyzed in a biomimetic approach. Contemporary biomedical and biophysical science has novel advances in technology that permit the design of more challenging and resilient in vitro models for tissue engineering, with a particular focus on scaffold- or hydrogel-based formats, organotypic cultures, and organs-on-chips, which cover the purposes of co-cultures. Even these complex systems must be kept as simplified as possible in order to grasp a particular section of physiology too very precisely. In particular, it is highly appreciated that they bridge the space between conventional animal research and human (patho)physiology. In this review, the recent progress in 3D biomimetic culturation is presented with a special focus on co-cultures, with an emphasis on the technological building blocks and endothelium-based co-culture models in cancer research that are available for the development of more physiologically relevant in vitro models of human tissues under normal and diseased conditions. Through applications and samples of various physiological and disease models, it is possible to identify the frontiers and future engagement issues that will have to be tackled to integrate synthetic biomimetic culture systems far more successfully into biomedical and biophysical investigations.

Endothelial Reprogramming in Sports Traumatology: Role of the Widespread Neuro-Immuno-Endocrine-Endothelial System

This paper deals with the role of the widespread neuro-immuno-endocrine-endothelial system in sport traumatology. The aim of this work is to see if sport or regular physical activity is able to reprogram the endothelium, to advance the new concept of neuro-immuno-endocrine-endothelial diffused system, and to introduce in the practice of sport medicine a new test in the fields of “Athlete functional evaluation” and “Sports fitness”. The first object of this paper is to see whether sport or regular physical activity can change the functional structure of the endothelium. The second goal is to frame under a general view the knowledge and individual lines of research on endothelium, to highlight what we believe is, in the organization of homeostasis, the location of this ‘organ’, namely in the neuro-immune-endocrine system spread.

Precision oncology using ex vivo technology: a step towards individualised cancer care?

Despite advances in cancer genomics and the increased use of genomic medicine, metastatic cancer is still mostly an incurable and fatal disease. With diminishing returns from traditional drug discovery strategies, and high clinical failure rates, more emphasis is being placed on alternative drug discovery platforms, such as ex vivo approaches. Ex vivo approaches aim to embed biological relevance and inter-patient variability at an earlier stage of drug discovery, and to offer more precise treatment stratification for patients. However, these techniques also have a high potential to offer personalised therapies to patients, complementing and enhancing genomic medicine. Although an array of approaches are available to researchers, only a minority of techniques have made it through to direct patient treatment within robust clinical trials. Within this review, we discuss the current challenges to ex vivo approaches within clinical practice and summarise the contemporary literature which has directed patient treatment. Finally, we map out how ex vivo approaches could transition from a small-scale, predominantly research based technology to a robust and validated predictive tool. In future, these pre-clinical approaches may be integrated into clinical cancer pathways to assist in the personalisation of therapy choices and to hopefully improve patient experiences and outcomes.

Biomaterial strategies for the application of reproductive tissue engineering

Human reproductive organs are of vital importance to the life of an individual and the reproduction of human populations. So far, traditional methods have a limited effect in recovering the function and fertility of reproductive organs and tissues. Thus, aim to replace and facilitate the regrowth of damaged or diseased tissue, various biomaterials are developed to offer hope to overcome these difficulties and help gain further research progress in reproductive tissue engineering. In this review, we focus on the biomaterials and their four main applications in reproductive tissue engineering: in vitro generation and culture of reproductive cells; development of reproductive organoids and models; in vivo transplantation of reproductive cells or tissues; and regeneration of reproductive tissue. In reproductive tissue engineering, designing biomaterials for different applications with different mechanical properties, structure, function, and microenvironment is challenging and important, and deserves more attention.

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Various biomaterials have been developed and used in reproductive tissue engineering.

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3D culture systems can lead to better cell-cell interactions for in vitro production of reproductive cells.

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Reproductive organoids and models are formed by biomaterials to simulate the environment of natural reproductive organs.

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Biomaterials should promote vascular regeneration and resist inflammation for in-situ reproductive tissue regeneration.

In Vitro Disease Models of the Endocrine Pancreas

The ethical constraints and shortcomings of animal models, combined with the demand to study disease pathogenesis under controlled conditions, are giving rise to a new field at the interface of tissue engineering and pathophysiology, which focuses on the development of in vitro models of disease. In vitro models are defined as synthetic experimental systems that contain living human cells and mimic tissue- and organ-level physiology in vitro by taking advantage of recent advances in tissue engineering and microfabrication. This review provides an overview of in vitro models and focuses specifically on in vitro disease models of the endocrine pancreas and diabetes. First, we briefly review the anatomy, physiology, and pathophysiology of the human pancreas, with an emphasis on islets of Langerhans and beta cell dysfunction. We then discuss different types of in vitro models and fundamental elements that should be considered when developing an in vitro disease model. Finally, we review the current state and breakthroughs in the field of pancreatic in vitro models and conclude with some challenges that need to be addressed in the future development of in vitro models.

Central nervous system tumors and three-dimensional cell biology: Current and future perspectives in modeling

Central nervous system (CNS) tumors are a variety of distinct neoplasms that present multiple challenges in terms of treatment and prognosis. Glioblastoma, the most common primary tumor in adults, is associated with poor survival and remains one of the least treatable neoplasms. These tumors are highly heterogenous and complex in their nature. Due to this complexity, traditional cell culturing techniques and methods do not provide an ideal recapitulating model for the study of these tumors’ behavior in vivo. Two-dimensional models lack the spatial arrangement, the heterogeneity in cell types, and the microenvironment that play a large role in tumor cell behavior and response to treatment. Recently, scientists have turned towards three-dimensional culturing methods, namely spheroids and organoids, as they have been shown to recapitulate tumors in a more faithful manner to their in vivo counterparts. Moreover, tumor-on-a-chip systems have lately been employed in CNS tumor modeling and have shown great potential in both studying the pathophysiology and therapeutic testing. In this review, we will discuss the current available literature on in vitro three-dimensional culturing models in CNS tumors, in addition to presenting their advantages and current limitations. We will also elaborate on the future implications of these models and their benefit in the clinical setting.

Rapid fabrication of gelatin-based scaffolds with prevascularized channels for organ regeneration

One of the biggest hinders in tissue engineering over the last decades was the complexity of the prevascularized channels of the engineered scaffold, which was still lower than that of human tissues. Another relative trouble was lacking precision molding capability, which restricted the clinical applications of the huge engineered scaffold. In this study, a promising approach was proposed to prepare hydrogel scaffold with prevascularized channels by liquid bath printing, which chitosan/β-sodium glycerophosphate (CS/β-GP) severed as the ink hydrogel, and gelation/nanoscale bacterial cellulose (Gel/BC) acted as the supporting hydrogel. Here, the ink hydrogel was printed by a versatile nozzle and embedded in the supporting hydrogel. Ink hydrogel transformed into liquid effluent at low temperature after cross-linking of gelatin by microbial transglutaminase (mTG). No residual template was seen on the channel surface after template removal. This preparation had a high degree of freedom in the geometry of the channel, which was demonstrated by making various prevascularized channels including circular, branched, and tree-shaped networks. The molding accuracy of the channel was detected by studying the roundness of the cross-section of the molded hollow channel, and the effect of the mechanical properties by adding BC to supporting hydrogel was analyzed. Human umbilical vein endothelial cells (HUVECs) were injected into the aforementioned channels and formed confluent and homogeneous distribution on the surface of channels. Altogether, these results showed that this approach can construct hydrogel scaffold with complex and accurate molding prevascularized channels, and had great potential to resolve urgent vascularization issue of bulk tissue-engineering scaffold.

Exosomes in Angiogenesis and Anti-angiogenic Therapy in Cancers

Angiogenesis is the process through which new blood vessels are formed from pre-existing ones. Exosomes are involved in angiogenesis in cancer progression by transporting numerous pro-angiogenic biomolecules like vascular endothelial growth factor (VEGF), matrix metalloproteinases (MMPs), and microRNAs. Exosomes promote angiogenesis by suppressing expression of factor-inhibiting hypoxia-inducible factor 1 (HIF-1). Uptake of tumor-derived exosomes (TEX) by normal endothelial cells activates angiogenic signaling pathways in endothelial cells and stimulates new vessel formation. TEX-driven cross-talk of mesenchymal stem cells (MSCs) with immune cells blocks their anti-tumor activity. Effective inhibition of tumor angiogenesis may arrest tumor progression. Bevacizumab, a VEGF-specific antibody, was the first antiangiogenic agent to enter the clinic. The most important clinical problem associated with cancer therapy using VEGF- or VEFGR-targeting agents is drug resistance. Combined strategies based on angiogenesis inhibitors and immunotherapy effectively enhances therapies in various cancers, but effective treatment requires further research.

The growth of endothelial-like cells in zebrafish embryoid body culture

There is increasing interest in the possibility of culturing organ-like tissues (organoids) in vitro for biomedical applications. The ability to culture organoids would be greatly enhanced by having a functional circulation in vitro. The endothelial cell is the most important cell type in this context. Endothelial cells can be derived from pluripotent embryonic blastocyst cells in aggregates called embryoid bodies. Here, we examine the yield of endothelial-like cells in embryoid bodies (EBs) developed from transgenic zebrafish fli:GFP and kdrl:GFP blastocyst embryos. The isolated blastocyst cells developed into EBs within the first 24 h of culture and contained fli:GFP⁺ (putative endothelial, hematopoietic and other cell types); or kdrl:GFP⁺ (endothelial) cells. The addition of endothelial growth supplements to the media and culture on collagen type-I substratum increased the percentages of fli:GFP⁺ and kdrl:GFP⁺ cells in culture. We found that EBs developed in hanging-drop cultures possessed a higher percentage of fli:GFP⁺ (45.0 ± 3.1%) and kdrl:GFP⁺ cells (8.7 ± 0.7%) than those developed on conventional substrata (34.5 ± 1.4% or 5.2 ± 0.4%, respectively). The transcriptome analysis showed a higher expression of VEGF and TGFβ genes in EB cultures compared to the adherent cultures. When transferred to conventional culture, the percentage of fli:GFP⁺ or kdrl:GFP⁺ cells declined significantly over subsequent days in the EBs. The fli:GFP⁺ cells formed a monolayer around the embryoid bodies, while the kdrl:GFP⁺ cells formed vascular network-like structures in the embryoid bodies. Differences were observed in the spreading of fli:GFP⁺ cells, and network formation of kdrl:GFP⁺ cells on different substrates. The fli:GFP⁺ cells could be maintained in primary culture and sub-cultures. By contrast, kdrl:GFP⁺ cells were almost completely absent at 8d of primary culture. Our culture model allows real-time observation of fli:GFP⁺ and kdrl:GFP⁺ cells in culture. The results obtained from this study will be important for the development of vascular and endothelial cell culture using embryonic cells.

Human Umbilical Vein Endothelial Cells (HUVECs) Co-Culture with Osteogenic Cells: From Molecular Communication to Engineering Prevascularised Bone Grafts

The repair of bone defects caused by trauma, infection or tumor resection is a major clinical orthopedic challenge. The application of bone grafts in orthopedic procedures is associated with a problem of inadequate vascularization in the initial phase after implantation. Meanwhile, the survival of cells within the implanted graft and its integration with the host tissue is strongly dependent on nutrient and gaseous exchange, as well as waste product removal, which are effectuated by blood microcirculation. In the bone tissue, the vasculature also delivers the calcium and phosphate indispensable for the mineralization process. The critical role of vascularization for bone healing and function, led the researchers to the idea of generating a capillary-like network within the bone graft in vitro, which could allow increasing the cell survival and graft integration with a host tissue. New strategies for engineering pre-vascularized bone grafts, that apply the co-culture of endothelial and bone-forming cells, have recently gained interest. However, engineering of metabolically active graft, containing two types of cells requires deep understanding of the underlying mechanisms of interaction between these cells. The present review focuses on the best-characterized endothelial cells-human umbilical vein endothelial cells (HUVECs)-attempting to estimate whether the co-culture approach, using these cells, could bring us closer to development and possible clinical application of prevascularized bone grafts.

Glioblastoma Model Using Human Cerebral Organoids

We have developed a cancer model of gliomas in human cerebral organoids that allows direct observation of tumor initiation as well as continuous microscopic observations. We used CRISPR/Cas9 technology to target an HRas^G12V-IRES-tdTomato construct by homologous recombination into the TP53 locus. Results show that transformed cells rapidly become invasive and destroy surrounding organoid structures, overwhelming the entire organoid. Tumor cells in the organoids can be orthotopically xenografted into immunodeficient NOD/SCID IL2RG^−/− animals, exhibiting an invasive phenotype. Organoid-generated putative tumor cells show gene expression profiles consistent with mesenchymal subtype human glioblastoma. We further demonstrate that human-organoid-derived tumor cell lines or primary human-patient-derived glioblastoma cell lines can be transplanted into human cerebral organoids to establish invasive tumor-like structures. Our results show potential for the use of organoids as a platform to test human cancer phenotypes that recapitulate key aspects of malignancy.

Brain Organoids: A New, Transformative Investigational Tool for Neuroscience Research

Brain organoids are self-assembled, three-dimensionally structured tissues that are typically derived from pluripotent stem cells. They are multicellular aggregates that more accurately recapitulate the tissue microenvironment compared to the other cell culture systems and can also reproduce organ function. They are promising models for evaluating drug leads, particularly those that target neurodegeneration, since they are genetically and phenotypically stable over prolonged durations of culturing and they reasonably reproduce critical physiological phenomena such as biochemical gradients and responses by the native tissue to stimuli. Beyond drug discovery, the use of brain organoids could also be extended to investigating early brain development and identifying the mechanisms that elicit neurodegeneration. Herein, the current state of the fabrication and use of brain organoids in drug development and medical research is summarized. Although the use of brain organoids represents a quantum leap over existing investigational tools used by the pharmaceutical industry, they are nonetheless imperfect systems that could be greatly improved through bioengineering. To this end, some key scientific challenges that would need to be addressed in order to enhance the relevance of brain organoids as model tissue are listed. Potential solutions to these challenges, including the use of bioprinting, are highlighted thereafter.

Sulodexide inhibits angiogenesis via decreasing Dll4 and Notch1 expression in mouse proepicardial explant cultures

Sulodexide (SDX) is a mixed drug containing low-molecular-weight heparin sulfate and dermatan sulfate. It exerts mild anticoagulant action but can also affect leukocytes, macrophages, and cell-cell adhesion and may interact with growth factors although its direct influence on endothelial cells is not well described. Clinically, SDX is used for the treatment of cardiovascular diseases, where it exerts anti-inflammatory and endothelial protective effects. The aim of this study was to determine the influence of SDX on tubule formation and angiogenesis-related proteins' mRNA expression in endothelial cell line C166 and mouse proepicardial explants. C166 cells and explants were stimulated with a proangiogenic cocktail containing bFGF/VEGF-A₁₂₀ /VEGF-A₁₆₄ enriched with SDX. After stimulation, the number and morphology of tubules stained with anti-CD31 antibody were examined under confocal microscope and expression of mRNA for VEGF-A, VEGF-B, VEGF-C, bFGF, IGF-1, Dll4, and Notch1 was measured with real-time PCR. In C166 cell line, there was no difference in tubule formation and mRNA expression, but in proepicardial explants, we observed reduction in tubule number and in mRNA level for DLL4 and Notch1 after SDX administration. In conclusion, SDX indirectly inhibits angiogenesis in mouse proepicardial explant cultures but has no direct effect on the C166 endothelial cell line.

The therapeutic potential of targeting the endothelial-to-mesenchymal transition

Endothelial cells (ECs) have been found to be capable of acquiring a mesenchymal phenotype through a process known as endothelial-to-mesenchymal transition (EndMT). First seen in the developing embryo, EndMT can be triggered postnatally under certain pathological conditions. During this process, ECs dedifferentiate into mesenchymal stem-like cells (MSCs) and subsequently give rise to cell types belonging to the mesoderm lineage. As EndMT contributes to a multitude of diseases, pharmacological modulation of the signaling pathways underlying EndMT may prove to be effective as a therapeutic treatment. Additionally, EndMT in ECs could also be exploited to acquire multipotent MSCs, which can be readily re-differentiated into various distinct cell types. In this review, we will consider current models of EndMT, how manipulation of this process might improve treatment of clinically important pathologies and how it could be harnessed to advance regenerative medicine and tissue engineering.

Shear stress: An essential driver of endothelial progenitor cells

The blood flow through vessels produces a tangential, or shear, stress sensed by their innermost layer (i.e., endothelium) and representing a major hemodynamic force. In humans, endothelial repair and blood vessel formation are mainly performed by circulating endothelial progenitor cells (EPCs) characterized by a considerable expression of vascular endothelial growth factor receptor 2 (VEGFR2), CD34, and CD133, pronounced tube formation activity in vitro, and strong reendothelialization or neovascularization capacity in vivo. EPCs have been proposed as a promising agent to induce reendothelialization of injured arteries, neovascularization of ischemic tissues, and endothelialization or vascularization of bioartificial constructs. A number of preconditioning approaches have been suggested to improve the regenerative potential of EPCs, including the use of biophysical stimuli such as shear stress. However, in spite of well-defined influence of shear stress on mature endothelial cells (ECs), articles summarizing how it affects EPCs are lacking. Here we discuss the impact of shear stress on homing, paracrine effects, and differentiation of EPCs. Unidirectional laminar shear stress significantly promotes homing of circulating EPCs to endothelial injury sites, induces anti-thrombotic and anti-atherosclerotic phenotype of EPCs, increases their capability to form capillary-like tubes in vitro, and enhances differentiation of EPCs into mature ECs in a dose-dependent manner. These effects are mediated by VEGFR2, Tie2, Notch, and β1/3 integrin signaling and can be abrogated by means of complementary siRNA/shRNA or selective pharmacological inhibitors of the respective proteins. Although the testing of sheared EPCs for vascular tissue engineering or regenerative medicine applications is still an unaccomplished task, favorable effects of unidirectional laminar shear stress on EPCs suggest its usefulness for their preconditioning.