Organoids

Gastric cancer (GC) presents a significant health challenge and ranks as the fifth most common cancer in the world. Unfortunately, most patients with GC exhaust standard care treatment options due to late diagnosis and tumour heterogeneity that leads to drug resistance, resulting in poor survival outcomes. Potentially, this situation can be improved by personalising treatment choice. Organoids are an emerging cell model system that recapitulates tumour heterogeneity and drug responses. Coupled with genomic analysis, organoid culture can be used to guide personalised medicine. The GC organoid field, however, lacks standardised methodologies for assessing organoid drug sensitivities. Comparing results across different GC organoid studies and correlating organoid drug responses with patient outcomes is challenging. Hence, we aim to summarise the methodologies used in GC organoid drug testing and correlation with clinical outcomes and discuss design considerations and limitations to enhance the robustness of such studies in the future. Full article

Tooth and periodontal organoids from stem and progenitor cells represent a significant advancement in regenerative dentistry, offering solutions for tooth loss and periodontal diseases. These organoids, which mimic the architecture and function of real organs, provide a cutting-edge platform for studying dental biology and developing therapies. Recent methodologies have been developed to optimize conditions for organoid production, advancing dental regenerative medicine, disease modeling, and developmental studies. The integration of bioengineering strategies with culture techniques enhances both our understanding and the therapeutic potential of these organoids. Additionally, factors such as the extracellular matrix, growth factors, and culture systems profoundly influence organoid formation and maturation. This review explores various bioengineering approaches for generating organoids, emphasizing the pivotal role of stem and progenitor cells. Full article

Recent advancements in vascular organoid (VO) and vessel-on-chip (VoC) technologies have revolutionized our approach to studying human diseases, offering unprecedented insights through more physiologically relevant models. VOs generated from human pluripotent stem cells exhibit remarkable self-organization capabilities, forming complex three-dimensional structures that closely mimic human blood vessel architecture and function, while VoCs are engineered with microfluidic systems that meticulously recreate the physical and functional attributes of blood vessels. These innovative constructs serve as powerful tools for investigating vascular development, disease progression, and therapeutic efficacy. By enabling the creation of patient-specific VOs and VoCs, they pave the way for personalized medicine approaches, allowing researchers to delve into genetic variations, intricate cellular interactions, and dynamic processes with exceptional resolution. The synergy between VOs and VoCs with newly developed cutting-edge technologies has further amplified their potential, unveiling novel mechanisms underlying human pathologies and identifying promising therapeutic targets. Herein, we summarize different types of VOs and VoCs and present an extensive overview on the generation and applications of VOs and VoCs. We will also highlight clinical and translational challenges and future perspectives around VOs and VoCs. Full article

Colorectal cancer (CRC) is the third most common cancer worldwide and it is the second leading cause of cancer death. In CRC, as in most cancers, the formation of metastasis through the migration and invasion of cancer cells to distant organs is associated with a dismal prognosis. The study of the mechanisms associated with cancer, and, in particular, CRC, changed in the last decade due to the introduction of organoids. These represent a step forward in terms of complexity from cell lines and allowed the use of mouse models in cancer research to be limited. Although organoids faithfully model the cellular complexity of CRC, current protocols do not allow for the use of organoids in some crucial processes of metastasis, such as migration and invasion. In this study, a method to study migration and invasion using mouse intestinal organoids in vitro is presented. This protocol provides researchers with the opportunity to investigate the migratory behavior of organoid lines and study the impact of distinct mutations on the migratory and invasive capacity of cancer cells. Full article

First trimester placental development comprises some of the most critical yet understudied events that impact fetal development. Improper placentation leads to a host of health issues that not only impact the fetal period but also influence offspring throughout their lives. Thus, a paradigm to study early placental development is necessary, and this has spurred on the pursuit of new in vitro model systems that recapitulate specific aspects of placentation. One of the most complex and translationally valid models to arise are organoids, three-dimensional structures comprising multiple differentiated cell types that originate from a common progenitor population. Trophoblasts are the progenitor cells of the placenta, serving as the proliferative base for placental development. Recent advances have enabled the derivation of organoids from primary tissue, yet access to first trimester human samples is ethically constrained; derivation from established trophoblast stem cell lines is an alternative source. Organoids have already proven useful in generating insights into molecular events that underlie trophoblast differentiation, with the identification of new cell subtypes that are primed to differentiate down different paths. In this review, (1) we recap early pregnancy development events, (2) provide an overview of the cellular complexity of the placenta, (3) discuss the generation of organoids from tissue versus cellular sources, (4) highlight the value of translational animal models, and (5) focus on the complexities of the molecular regulation of trophoblast organoid development, differentiation, and function. Full article

Globally, a number of diseases impact us and while treatment options exist, it is often found that similar treatments have variable effects on different patients with the same disease. Particularly in the case of conditions that are closely associated with genetics (like cancer), the intensity and results of a treatment vary between patients. Even for diseases like arthritis it is not uncommon for only a fraction of patients to achieve remission with the same therapeutic approach. With millions suffering from diseases like cancer and arthritis, precision medicine (PM) has been at the forefront of biomedical and pharmaceutical research since 2015. PM focusses on understanding the genetic and environmental factors affecting the patients and has several platforms. One of the platforms is the use of three-dimensional (3D) in vitro models, especially those derived from the patient themselves. These models, like organ-on-chip (OOC), organoid and spheroid models, 3D biomaterial scaffolds and others, have several advantages over traditional two-dimensional (2D) cell culture approaches. In this opinion paper, the author briefly discusses the different platforms used for PM. Then, the advantages that 3D in vitro models have over traditional 2D models and in vivo models are considered and an overview of their applications is provided. Finally, the author outlines the challenges and future directions and shares their opinion about using 3D in vitro models as a tool for PM towards enhanced patient outcomes. Full article

In zebrafish and various mammalian species, HB-EGF has been shown to promote Müller glia proliferation and activation of repair mechanisms that have not been fully investigated in human retina. In the current study, 70- to 90-day-old human retinal organoids were treated with 20 μM 4-hydroxytamoxifen (4-OHT), and CRX, REC, NRL, PAX6, VIM, GFAP, and VSX2 gene and protein expression were assessed at various times points after treatment. Organoids with or without 4-OHT-induced damage were then cultured with HB-EGF for 7 days. We showed that 20 μM 4-OHT caused a reduction in the number of recoverin-positive cells; an increase in the number of TUNEL-positive cells; and downregulation of the photoreceptor gene markers CRX, NRL, and REC. Culture of organoids with HB-EGF for 7 days after 4-OHT-induced damage caused a marked reduction in the number of TUNEL-positive cells and small increases in the number of Ki67-positive cells and PAX6 and NOTCH1 gene expression. The current results suggest that treatment of human ESC-derived retinal organoids with 4-OHT may be used as a model of retinal degeneration in vitro. Furthermore, HB-EGF treatment of human retinal organoids increases proliferating Müller cells, but only after 4-OHT induced damage, and may be an indication of Muller reactivity in response to photoreceptor damage. Further studies will aim to identify factors that may induce Müller cell-mediated regeneration of the human retina, aiding in the development of therapies for retinal degeneration. Full article

The mesolimbic pathway connects ventral tegmental area dopaminergic neurons and striatal medium spiny neurons, playing a critical role in reward and stress behaviors. Exposure to substances of abuse during development and adulthood has been linked to adverse outcomes and molecular changes. The rise of human cell repositories and whole-genome sequences enables human functional genomics ‘in a dish’, offering insights into human-specific responses to substances of abuse. Continued development of new models is needed, and the characterization of in vitro models is also necessary to ensure appropriate experimental designs and the accurate interpretation of results. This study introduces new culture conditions for generating medium spiny neurons and dopaminergic neurons with an early common media, allowing for coculture and assembloid generation. It then provides a comprehensive characterization of these and prior models and their responses to substances of abuse. Single-cell analysis reveals cell-type-specific transcriptomic responses to dopamine, cocaine, and morphine, including compound and cell-type-specific transcriptomic signatures related to neuroinflammation and alterations in signaling pathways. These findings offer a resource for future genomics studies leveraging human stem cell-derived models. Full article

In recent years, 3D cell culture systems have emerged as sophisticated in vitro models, providing valuable insights into human physiology and diseases. The transition from traditional 2D to advanced 3D cultures has introduced novel obstacles, complicating the characterization and analysis of these models. While the lactate dehydrogenase (LDH) activity assay has long been a standard readout for viability and cytotoxicity assessments in 2D cultures, its applicability in long-term 3D cultures is hindered by inappropriate normalization and low LDH stability over time. In response to these challenges, we propose an optimization of LDH assays, including a crucial normalization step based on total protein quantification and a storage method using an LDH preservation buffer. We applied it to compare unexposed cerebral organoids with organoids exposed to a toxic dose of valproic acid, and showed efficient normalization of cellular viability as well as enhanced LDH stability within the buffer. Importantly, normalized LDH activity results obtained were independent of organoid dimension and cell density. This refined LDH assay, tailored to address 3D culture constraints, allows for the transposition of this routine test from 2D to 3D cultures. Full article

Organoids present immense promise for studying organ systems and their functionality. Recently, they have become the subject of exploration outside of purely biomedical uses in multiple directions. We will explore the rapidly evolving landscape of organoid research over the 21st century, discussing significant advancements in organoid research and highlighting breakthroughs, methodologies, and their transformative impact on our understanding of physiology and modeling. In addition, we will explore their potential use for biocomputing and harnessing organoid intelligence, investigate how these miniaturized organ-like structures promise to create novel computational models and processing platforms allowing for innovative approaches in drug discovery, personalized medicine, and disease prediction. Lastly, we will address the ethical dilemmas surrounding organoid research by dissecting the intricate ethical considerations related to the creation, use, and potential implications of these in vitro models. Through this work, the goal of this paper is to provide introductory perspectives and bridges that will connect organoids to cybersecurity applications and the imperative ethical discourse accompanying its advancements with commentary on future uses. Full article

For over 150 years, researchers have studied the (patho)physiology of the endocrine pancreas and devised treatment options for diabetes mellitus (DM). However, no cure has been developed so far. In dogs, diabetes mellitus type 1 (T1DM) is the most common presentation. Treatment consists of twice daily insulin injections, monitored by spatial blood glucose measurements. Even though dogs were instrumental in the discovery of insulin and islet transplantations, the treatment in diabetic dogs has remained unchanged for decades. Providing twice daily insulin injections is demanding for both owners and dogs and may result in hypoglycaemic events, creating the need for new treatment strategies. Novel regenerative medicine-based tools, such as improved β-cell culture protocols and artificial devices, have sparked hope for a cure. In human medicine, emerging technologies such as the transplantation of insulin-producing β-cells, generated by stem cell differentiation, with or without an encapsulation device, are currently tested in phase I/II clinical trials. As the pathogenesis of T1DM is remarkably similar between humans and dogs, novel treatment methods could be implemented in canine medicine. This review briefly summarises the physiology of the canine endocrine pancreas and the pathophysiology of canine DM before exploring current and possible future treatment options for canine DM. Full article

Studying human placental development and function presents significant challenges due to the inherent difficulties in obtaining and maintaining placental tissue throughout the course of an ongoing pregnancy. Here, we provide a detailed protocol for generating trophoblast organoids from chorionic villi obtained during ongoing pregnancy. Our method results in efficient generation of trophoblast organoids from chorionic villus sampling, does not require preselection of chorionic villi, and controls contamination of decidual gland organoids. The resulting trophoblast organoids spontaneously form syncytiotrophoblasts that start secreting hCG hormone amongst other placenta-specific factors. Our approach facilitates the generation of trophoblast organoids from a variety of genetic backgrounds, including trisomies and gene mutations, and can be aligned with prenatal diagnostic routines. The protocol requires up to 14 days and can be carried out by users with expertise in cell culture. Full article

Osteosarcomas are the most common primary malignant bone tumors and mostly affect children, adolescents, and young adults. Despite current treatment options such as surgery and polychemotherapy, the survival of patients with metastatic disease remains poor. In recent studies, punicalagin has reduced the cell viability, angiogenesis, and invasion in cell culture trials. The aim of this study was to examine the effects of punicalagin on osteosarcomas in a 3D in vivo tumor model. Human osteosarcoma biopsies and SaOs-2 and MG-63 cells, were grown in a 3D in vivo chorioallantoic membrane (CAM) model. After a cultivation period of up to 72 h, the tumors received daily treatment with punicalagin for 4 days. Weight measurements of the CAM tumors were performed, and laser speckle contrast imaging (LSCI) and a deep learning-based image analysis software (CAM Assay Application v.3.1.0) were used to measure angiogenesis. HE, Ki-67, and Caspase-3 staining was performed after explantation. The osteosarcoma cell lines SaOs-2 and MG-63 and osteosarcoma patient tissue displayed satisfactory growth patterns on the CAM. Treatment with punicalagin decreased tumor weight, proliferation, and tumor-induced angiogenesis, and the tumor tissue showed pro-apoptotic characteristics. These results provide a robust foundation for the implementation of further studies and show that punicalagin offers a promising supplementary treatment option for osteosarcoma patients. The 3D in vivo tumor model represents a beneficial model for the testing of anti-cancer therapies. Full article

Existing mRNA COVID-19 vaccines have shown efficacy in reducing severe cases and fatalities. However, their effectiveness against infection caused by emerging SARS-CoV-2 variants has waned considerably, necessitating the development of variant vaccines. Ideally, next-generation vaccines will be capable of eliciting broader and more sustained immune responses to effectively counteract new variants. Additionally, in vitro assays that more closely represent virus neutralization in humans would greatly assist in the analysis of protective vaccine-induced antibody responses. Here, we present findings from a SARS-CoV-2 VLP vaccine encompassing three key structural proteins: Spike (S), Envelope (E), and Membrane (M). The VLP vaccine effectively produced neutralizing antibodies as determined by surrogate virus neutralization test, and induced virus-specific T-cell responses: predominantly CD4⁺, although CD8⁺ T cell responses were detected. T cell responses were more prominent with vaccine delivered with AddaVax compared to vaccine alone. The adjuvanted vaccine was completely protective against live virus challenge in mice. Furthermore, we utilized air–liquid-interface (ALI)-differentiated human nasal epithelium (HNE) as an in vitro system, which authentically models human SARS-CoV-2 infection and neutralization. We show that immune sera from VLP-vaccinated mice completely neutralized SARS-CoV-2 virus infection, demonstrating the potential of ALI-HNE to assess vaccine induced Nab. Full article

Although significant improvements have been made in the treatment of pancreatic cancer, its prognosis remains poor with an overall 5-year survival rate of less than 10%. New experimental approaches are necessary to develop novel therapeutics. In this study, the investigation of pancreatic cancer tissue growth in the chorioallantoic membrane (CAM) model and the subsequent use of indocyanine green (ICG) injections for the verification of intratumoral perfusion was conducted. ICG was injected into the CAM vasculature to visualize the perfusion of the tumor tissue. The presence of metastasis was investigated through PCR for the human-specific ALU element in the liver of the chicken embryo. Additionally, the usage of cryopreserved pancreatic tumors was established. Intratumoral perfusion of tumor tissue on the CAM was observed in recently obtained and cryopreserved tumors. ALU-PCR detected metastasis in the chick embryos’ livers. After cryopreservation, the tissue was still vital, and the xenografts generated from these tumors resembled the histological features of the primary tumor. This methodology represents the proof of principle for intravenous drug testing of pancreatic cancer in the CAM model. The cryopreserved tumors can be used for testing novel therapeutics and can be integrated into the molecular tumor board, facilitating personalized tumor treatment. Full article

Organoids have emerged as a powerful tool for studying organ development, disease modeling, and drug discovery due to their ability to mimic the in vivo structure and function of organs in a three-dimensional in vitro model. During in vivo organ maturation, the process of vascularization is crucial for the provision of nutrients and oxygen to cells and the removal of waste products as the organ increases in size. Similarly, organoids can grow to sizes greater than the millimeter scale, yet transport of oxygen and nutrients to the center becomes increasingly difficult, often resulting in the formation of a necrotic core. Herein, we provide a concise summary of the recent development of methods to initiate and maintain vascularization of organoids. Broadly, vascularization of organoids has been achieved primarily by two means: generating organoids that contain endothelial cells or employing the secretion of vascular growth factors to promote vascularization. Growth factors play a fundamental role in regulating blood vessel formation through chemical signals that cause changes in the cell–cell adhesions and ultimately the migration of endothelial cells. Furthermore, models with perfusable systems demonstrate that through the application of growth factors and cells, the vascular network in vascularization-based organoids can administer biological substances to the interior of the organoid, opening up new possibilities for long-term organoid culture in vitro. This goal is being realized through the development of bioengineering tools, such as vascularized organoids on a chip, which are currently tested for various organ systems, including the lung, brain, kidney, and tumors, with applications in cancer angiogenesis and metastasis research. Taken together, our review underlines the vast potential of vascularized organoids to improve the understanding of organ development, while also proposing exciting avenues of organoid-on-a-chip and disease modeling. Full article

While research on stem cell-derived tissues and organoids is rapidly expanding, the technically related creation of complex embryoids has recently excited a vivid discussion since it raises ethical questions about individuation and the possible gain of viability. The present study focuses on the onset of organismic development and the proposed biological and legal definitions for the terms embryo, embryoid, and organoid. It is concluded that such considerations have become important for investigators’ choices of the appropriate in vitro model systems, allowing the formation of organoids vs. complex embryoids. Full article

Meningiomas are the most common tumours of the central nervous system. According to the World Health Organization (WHO), this disease is classified into three different grades: 80% of meningioma patients present with benign grade I tumours, while less than 2% present with malignant grade III meningiomas. Despite affecting thousands of people worldwide, much remains unknown about this disease, and the development of systemic treatments is still far behind in comparison to other types of tumours. Therefore, forming 3D structures (spheroids and organoids) could facilitate research on the mechanisms of formation, proliferation, migration, and invasion of these, for the most part, benign tumours, while also helping in the process of drug development. To date, there are three published methods for the formation of meningioma organoids primarily derived from patient tissue samples. Organoids offer many advantages in the development of treatments because they recapitulate the cellular complexity within tumours. These new methodological advances could open a substantial number of possibilities for the further characterisation and treatment of meningiomas. This review includes an overview of the disease and a description and comparison of established protocols for meningioma organoid formation. Full article