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76-493: An organoid is a miniaturised and simplified version of an organ produced in vitro in three dimensions that mimics the key functional, structural, and biological complexity of that organ. It is derived from one or a few cells from a tissue , embryonic stem cells , or induced pluripotent stem cells , which can self-organize in three-dimensional culture owing to their self-renewal and differentiation capacities. The technique for growing organoids has rapidly improved since

152-497: A fully CFTR dependent manner. Whereas organoids from non-cystic fibrosis subjects swell in response to forskolin as a consequence of fluid transport into the organoids' lumens, this is severely reduced or absent in organoids derived from people with cystic fibrosis. Swelling could be restored by therapeutics that repair the CFTR protein (CFTR modulators), indicating that individual responses to CFTR modulating therapy could be quantitated in

228-724: A genetic form of microcephaly , where patient cells were used to make cerebral organoids , which were smaller and showed abnormalities in early generation of neurons. In another example, the genome editing system called CRISPR was applied to human pluripotent stem cells to introduce targeted mutations in genes relevant to two different kidney diseases, polycystic kidney disease and focal segmental glomerulosclerosis . These CRISPR-modified pluripotent stem cells were subsequently grown into human kidney organoids, which exhibited disease-specific phenotypes. Kidney organoids from stem cells with polycystic kidney disease mutations formed large, translucent cyst structures from kidney tubules. When cultured in

304-449: A living thing [there is] truth") is a play on in vino veritas , ("in wine [there is] truth"), a well-known proverb. In microbiology , in vivo is often used to refer to experimentation done in a whole organism , rather than in live isolated cells , for example, cultured cells derived from biopsies . In this situation, the more specific term is ex vivo . Once cells are disrupted and individual parts are tested or analyzed, this

380-433: A manner similar to in vivo , and exhibits the following properties: Organoid formation generally requires culturing the stem cells or progenitor cells in a 3D medium. Stem cells have the ability to self-renew and differentiate into various cell subtypes, and they enable understanding the processes of development and disease progression. Therefore organoids derived from stem cells enable studying biology and physiology at

456-460: A more natural route starting from the intestinal lumen, microinjection of the pathogen is required. In addition, the polarity of intestinal organoids can be inverted, and they can even be dissociated into single cells and cultured as 2D monolayers in order to make both the apical and basolateral sides of the epithelium more easily accessible. Intestinal organoids have also demonstrated therapeutic potential. In order to more accurately recapitulate

532-528: A multitude of organs. In the 1990s, in addition to their role in physical support, the role of ECM components in gene expression by their interaction with integrin-based focal adhesion pathways was reported. In 2006, Yaakov Nahmias and David Odde showed the self-assembly of vascular liver organoid maintained for over 50 days in vitro . In 2008, Yoshiki Sasai and his team at RIKEN institute demonstrated that stem cells can be coaxed into balls of neural cells that self-organize into distinctive layers. In 2009

608-737: A patient with Mainzer-Saldino Syndrome due to compound heterozygous mutations in IFT140 were compared to an isogenic control organoid in which an IFT140 variant giving rise to a non-viable mRNA transcript was corrected by CRISPR. Patient kidney organoids demonstrated abnormal ciliary morphology consistent with existing animal models which was rescued to wild type morphology in the gene corrected organoids. Comparative transcriptional profiling of epithelial cells purified from patient and control organoids highlighted pathways involved in cell polarity , cell-cell junctions and dynein motor assembly, some of which had been implicated for other genotypes within

684-583: A patient's metastatic tumor population , and identified that unlike the patient's primary tumor, the metastasis had both alleles of the TGFBR2 gene mutated. To further assess the role of TGFBR2 in the metastasis, the investigators created organoids where TGFBR2 expression is knocked down, through which they were able to demonstrate that reduced TGFBR2 activity leads to invasion and metastasis of cancerous tumors both in vitro and in vivo . Lingual organoids are organoids that recapitulate, at least partly, aspects of

760-497: A preclinical laboratory setting. Schwank et al. also demonstrated that the intestinal cystic fibrosis organoid phenotype could be repaired by CRISPR-Cas9 gene editing in 2013. Follow-up studies by Dekkers et al. in 2016 revealed that quantitative differences in forskolin-induced swelling between intestinal organoids derived from people with cystic fibrosis associate with known diagnostic and prognostic markers such as CFTR gene mutations or in vivo biomarkers of CFTR function. In addition,

836-427: A three-dimensional structure using rotational bioreactor and develop over the course of months. The procedure has potential applications in the study of brain development, physiology and function. Cerebral organoids may experience "simple sensations" in response to external stimulation and neuroscientists are among those expressing concern that such organs could develop sentience . They propose that further evolution of

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912-778: A valuable model to study intestinal nutrient transport, drug absorption and delivery, nanomaterials and nanomedicine, incretin hormone secretion, and infection by various enteropathogens. For example, Qun Wang's team rationally designed artificial virus nanoparticles as oral drug delivery vehicles (ODDVs) with gut organoid-derived mucosal models and demonstrated a new concept of using newly established colon organoids as tools for high-throughput drug screening, toxicity testing, and oral drug development. Or recently, Sakib, S., and Zou, S. developed graphene oxide nanoparticles for delivering siRNA regulating expression of tumor necrosis factor-α, that aimed to treat intestinal organoids exhibiting an inflammatory phenotype. Intestinal organoids also recapitulate

988-416: A variety of organ systems . These specific systems are widely studied in human anatomy . The functions of these organ systems often share significant overlap. For instance, the nervous and endocrine system both operate via a shared organ, the hypothalamus . For this reason, the two systems are combined and studied as the neuroendocrine system . The same is true for the musculoskeletal system because of

1064-491: A well characterised marker of nephron progenitor cells in the cap mesenchyme , the authors concluded that renal disease frequently seen in Lowe Syndrome (global failure of proximal tubule reabsorption or renal Fanconi syndrome ) could be related to alteration in nephron patterning arising from nephron progenitor cells lacking this important SIX2 gene expression. Other studies have used CRISPR gene editing to correct

1140-687: A whole, are referred to as the Organon because logic is a tool for philosophical thinking. Earlier thinkers, such as those who wrote texts in the Hippocratic corpus , generally did not believe that there were organs of the body but only different parts of the body. Some alchemists (e.g. Paracelsus ) adopted the Hermetic Qabalah assignment between the seven vital organs and the seven classical planets as follows: Chinese traditional medicine recognizes eleven organs, associated with

1216-458: Is known as in vitro . According to Christopher Lipinski and Andrew Hopkins, "Whether the aim is to discover drugs or to gain knowledge of biological systems, the nature and properties of a chemical tool cannot be considered independently of the system it is to be tested in. Compounds that bind to isolated recombinant proteins are one thing; chemical tools that can perturb cell function another; and pharmacological agents that can be tolerated by

1292-579: Is now easily achievable and affords high-throughput screening of these tumors against the current panel of approved drugs form around the world. Self-assembled cell aggregates consisting of BMECs, astrocytes, and pericytes are emerging as a potential alternative to transwell and microfluidic models for certain applications. These organoides can generate many features of the BBB, such as the expression of tight junctions, molecular transporters, and drug efflux pumps, and can therefore be used to model drug transport across

1368-404: Is of great relevance in the context of malabsorption diseases as well as metabolic diseases such as obesity , insulin resistance , and diabetes . Organoids provide an opportunity to create cellular models of human disease, which can be studied in the laboratory to better understand the causes of disease and identify possible treatments. The power of organoids in this regard was first shown for

1444-406: Is the placenta , which has evolved more than 100 times independently in vertebrates, has evolved relatively recently in some lineages, and exists in intermediate forms in extant taxa. Studies on the evolution of the placenta have identified a variety of genetic and physiological processes that contribute to the origin and evolution of organs, these include the re-purposing of existing animal tissues,

1520-607: The Austrian Academy of Sciences established a protocol starting from pluripotent stem cells to generate cerebral organoids that mimic the developing human brain's cellular organization. Meritxell Huch and Craig Dorrell at Hubrecht Institute and University Medical Center Utrecht demonstrated that single Lgr5+ cells from damaged mouse liver can be clonally expanded as liver organoids in Rspo1-based culture medium over several months. In 2014, Artem Shkumatov et al. at

1596-528: The LGR5 + or CD44 + stem/progenitor cells of circumvallate (CV) papilla tissue. These taste bud organoids have been successfully created both directly from isolated Lgr5- or LGR6 -expressing taste stem/progenitor cells. and indirectly, through the isolation, digestion, and subsequent culturing of CV tissue containing Lgr5+ or CD44+ stem/progenitor cells. 3D organoid models of brain cancer derived from either patient derived explants (PDX) or direct from cancer tissue

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1672-425: The crypt-Villus structure to such a high degree of fidelity that they have been successfully transplanted to mouse intestines, and are hence highly regarded as a valuable model for research. One of the fields of research that intestinal organoids have been utilized is that of stem cell niche. Intestinal organoids were used to study the nature of the intestinal stem cell niche , and research done with them demonstrated

1748-431: The five Chinese traditional elements and with yin and yang , as follows: The Chinese associated the five elements with the five planets (Jupiter, Mars, Venus, Saturn, and Mercury) similar to the way the classical planets were associated with different metals. The yin and yang distinction approximates the modern notion of solid and hollow organs. In vivo Studies that are in vivo ( Latin for "within

1824-408: The gastrointestinal tract . The gastrointestinal tract arises from the endoderm , which during development forms a tube that can be divided in three distinct regions, which give rise to, along with other organs, the following sections of the gastrointestinal tract: Organoids have been created for the following structures of the gastrointestinal tract: Intestinal organoids have thus far been among

1900-418: The haruspices or the augurs in order to divine the future by their shape, dimensions or other factors. This practice remains an important ritual in some remote, tribal societies. The term "visceral" is contrasted with the term " parietal ", meaning "of or relating to the wall of a body part, organ or cavity " The two terms are often used in describing a membrane or piece of connective tissue, referring to

1976-424: The pathogenesis of disease by comparing the effects of bacterial infection with the effects of purified bacterial toxins ; the development of non-antibiotics, antiviral drugs, and new drugs generally; and new surgical procedures. Consequently, animal testing and clinical trials are major elements of in vivo research. In vivo testing is often employed over in vitro because it is better suited for observing

2052-417: The stomach , intestines , gallbladder , bladder , and rectum . In the thoracic cavity , the heart is a hollow, muscular organ. Splanchnology is the study of the viscera. The term "visceral" is contrasted with the term " parietal ", meaning "of or relating to the wall of a body part, organ or cavity ". The two terms are often used in describing a membrane or piece of connective tissue, referring to

2128-461: The 20th century, organ transplants began to take place as scientists knew more about the anatomy of organs. These came later in time as procedures were often dangerous and difficult. Both the source and method of obtaining the organ to transplant are major ethical issues to consider, and because organs as resources for transplant are always more limited than demand for them, various notions of justice, including distributive justice , are developed in

2204-404: The BBB. Also, they can serve as a model for evaluating the interactions between the BBB and adjacent brain tissue and provide a platform for understanding the combined abilities of a new drug to overcome the BBB and its effect on brain tissue. In addition, such models are highly scalable and easier to manufacture and operate than microfluidic devices. However, they have limited ability to reconstruct

2280-488: The CRISPR mutations. Comparison of these organoid phenotypes to diseased tissues from mice and humans suggested similarities to defects in early development. As first developed by Takahashi and Yamanaka in 2007, induced pluripotent stem cells (iPSC) can also be reprogrammed from patient skin fibroblasts. These stem cells carry the exact genetic background of the patient including any genetic mutations which might contribute to

2356-617: The Laboratory of Hans Clevers at Hubrecht Institute and University Medical Center Utrecht , Netherlands, showed that single LGR5 -expressing intestinal stem cells self-organize to crypt-villus structures in vitro without necessity of a mesenchymal niche, making them the first organoids. In 2010, Mathieu Unbekandt & Jamie A. Davies demonstrated the production of renal organoids from murine fetus-derived renogenic stem cells. In 2014, Qun Wang and co-workers engineered collagen-I and laminin based gels and synthetic foam biomaterials for

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2432-568: The University of Illinois at Urbana-Champaign demonstrated that cardiovascular organoids can be formed from ES cells through modulation of the substrate stiffness, to which they adhere. Physiological stiffness promoted three-dimensionality of EBs and cardiomyogenic differentiation. Lancaster and Knoblich define an organoid as a collection of organ-specific cell types that develops from stem cells or organ progenitors, self-organizes through cell sorting and spatially restricted lineage commitment in

2508-414: The absence of adherent cues (in suspension), these cysts reached sizes of 1 cm in diameter over several months. Kidney organoids with mutations in a gene linked to focal segmental glomerulosclerosis developed junctional defects between podocytes, the filtering cells affected in that disease. Importantly, these disease phenotypes were absent in control organoids of identical genetic background, but lacking

2584-441: The acquisition of new functional properties by these tissues, and novel interactions of distinct tissue types. The study of plant organs is covered in plant morphology . Organs of plants can be divided into vegetative and reproductive. Vegetative plant organs include roots , stems , and leaves . The reproductive organs are variable. In flowering plants , they are represented by the flower , seed and fruit . In conifers ,

2660-440: The advancements in 3D culturing techniques allowed for the creation of organoids that recapitulate the properties of various specific subregions of a multitude of organs. The use of these organoids has thus greatly contributed to expanding our understanding of the processes of organogenesis , and the field of developmental biology. In central nervous system development, for example, organoids have contributed to our understanding of

2736-452: The authors demonstrated that CFTR modulator responses in intestinal organoids with specific CFTR mutations correlated with published clinical trial data of these treatments. This led to preclinical studies where organoids from patients with extremely rare CFTR mutations for who no treatment was registered were found to respond strongly to a clinically available CFTR modulator. The suggested clinical benefit of treatment for these subjects based on

2812-491: The culture and delivery of intestinal organoids and encapsulated DNA-functionalized gold nanoparticles into intestinal organoids to form an intestinal Trojan horse for drug delivery and gene therapy. Subsequent reports showed significant physiological function of these organoids in vitro and in vivo . Other significant early advancements included in 2013, Madeline Lancaster at the Institute of Molecular Biotechnology of

2888-399: The development of human disease. Differentiation of these cells into kidney organoids has been performed from patients with Lowe Syndrome due to ORCL1 mutations. This report compared kidney organoids differentiated from patient iPSC to unrelated control iPSC and demonstrated an inability of patient kidney cells to mobilise transcription factor SIX2 from the golgi complex . Because SIX2 is

2964-573: The development of the complex 3-dimensional structures of organs. Utilization of 3D media culture media methods for the structural organization was made possible with the development of extracellular matrices (ECM). In the late 1980s, Bissell and colleagues showed that a laminin rich gel can be used as a basement membrane for differentiation and morphogenesis in cell cultures of mammary epithelial cells. Since 1987, researchers have devised different methods for 3D culturing, and were able to utilize different types of stem cells to generate organoids resembling

3040-642: The duodenum of mice has been shown to aid in the recovery of mucosal damages on mice with ischemia-reperfusion injury. The first successful transplantation of an organoid into a human, a patient with ulcerative colitis whose cells were used for the organoid, was carried out in 2022. Organoids offer researchers an exceptional model to study developmental biology . Since the identification of pluripotent stem cells , there have been great advancements in directing pluripotent stem cells fate in vitro using 2D cultures. These advancements in PSC fate direction, coupled with

3116-414: The early 2010s, and The Scientist named it one of the biggest scientific advancements of 2013. Scientists and engineers use organoids to study development and disease in the laboratory , for drug discovery and development in industry, personalized diagnostics and medicine, gene and cell therapies, tissue engineering, and regenerative medicine. Attempts to create organs in vitro started with one of

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3192-402: The ethical analysis. This situation continues as long as transplantation relies upon organ donors rather than technological innovation, testing, and industrial manufacturing. The English word "organ" dates back to the twelfth century and refers to any musical instrument. By the late 14th century, the musical term's meaning had narrowed to refer specifically to the keyboard-based instrument . At

3268-577: The first application of organoids for personalised treatment. Cystic fibrosis is an inherited disease that is caused by gene mutations of the cystic fibrosis transmembrane conductance regulator gene that encodes an epithelial ion channel necessary for healthy epithelial surface fluids. Studies by the laboratory of Jeffrey Beekman (Wilhelmina Children's Hospital, University Medical Center Utrecht, The Netherlands) described in 2013 that stimulation of colorectal organoids with cAMP-raising agonists such as forskolin or cholera toxin induced rapid swelling of organoids in

3344-461: The first dissociation-reaggregation experiments where Henry Van Peters Wilson demonstrated that mechanically dissociated sponge cells can reaggregate and self-organize to generate a whole organism. In the subsequent decades, multiple labs were able to generate different types of organs in vitro through the dissociation and reaggregation of organ tissues obtained from amphibians and embryonic chicks. The formation of first tissue-like colonies in vitro

3420-705: The gut organoids generated directly from intestinal tissues or pluripotent stem cells. One way human pluripotent stem cells can be driven to form intestinal organoids is through first the application of activin A to drive the cells into a mesoendodermal identity, followed by the pharmacological upregulation of Wnt3a and Fgf4 signaling pathways as they have been demonstrated to promote posterior gut fate. Intestinal organoids have also been generated from intestinal stem cells, extracted from adult tissue and cultured in 3D media. These adult stem cell-derived organoids are often referred to as enteroids or colonoids, depending on their segment of origin, and have been established from both

3496-409: The human and murine intestine. Intestinal organoids consist of a single layer of polarized intestinal epithelial cells surrounding a central lumen. As such, recapitulate the crypt-villus structure of the intestine, by recapitulating its function, physiology and organization, and maintaining all the cell types found normally in the structure including intestinal stem cells. Thus, intestinal organoids are

3572-525: The inner mass of organoids can be achieved through microfluidic systems, vascular endothelial growth factor delivery systems, and endothelial cell-coated modules. With patient-derived induced pluripotent stem cells (iPSCs) and CRISPR/Cas -based genome editing technologies, genome-edited or mutated pluripotent stem cells (PSCs) with altered signaling cues can be generated to control intrinsic cues within organoids. A multitude of organ structures have been recapitulated using organoids. This section aims to outline

3648-425: The intestine in vivo , co-cultures of intestinal organoids and immune cells have been developed. Furthermore, organ-on-a-chip models combine intestinal organoids with other cell types such as endothelial or immune cells as well as peristaltic flow. Gastric organoids recapitulate at least partly the physiology of the stomach . Gastric organoids have been generated directly from pluripotent stem cells through

3724-468: The liver and heart evolved in the chordates about 550-500 million years ago, while the gut and brain are even more ancient, arising in the ancestor of vertebrates, insects, molluscs, and worms about 700–650 million years ago. Given the ancient origin of most vertebrate organs, researchers have looked for model systems, where organs have evolved more recently, and ideally have evolved multiple times independently. An outstanding model for this kind of research

3800-526: The living"; often not italicized in English ) are those in which the effects of various biological entities are tested on whole, living organisms or cells , usually animals , including humans , and plants, as opposed to a tissue extract or dead organism. This is not to be confused with experiments done in vitro ("within the glass"), i.e., in a laboratory environment using test tubes , Petri dishes , etc. Examples of investigations in vivo include:

3876-399: The mid-1950s found that sterile filtrates of serum from animals infected with Bacillus anthracis were lethal for other animals, whereas extracts of culture fluid from the same organism grown in vitro were not. This discovery of anthrax toxin through the use of in vivo experiments had a major impact on studies of the pathogenesis of infectious disease. The maxim in vivo veritas ("in

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3952-420: The morphology and physiology of the BBB and are unable to simulate physiological flow and shear stress . Organoids enable to study how cells interact together in an organ, their interaction with their environment, how diseases affect them and the effect of drugs. In vitro culture makes this system easy to manipulate and facilitates their monitoring. While organs are difficult to culture because their size limits

4028-467: The new generation of plants (see clonal colony ). Many societies have a system for organ donation , in which a living or deceased donor's organ are transplanted into a person with a failing organ. The transplantation of larger solid organs often requires immunosuppression to prevent organ rejection or graft-versus-host disease . There is considerable interest throughout the world in creating laboratory-grown or artificial organs . Beginning in

4104-403: The opposing sides. Aristotle used the word frequently in his philosophy, both to describe the organs of plants or animals (e.g. the roots of a tree, the heart or liver of an animal) because, in ancient Greek, the word ' organon ' means 'tool', and Aristotle believed that the organs of the body were tools for us by means of which we can do things. For similar reasons, his logical works, taken as

4180-406: The opposing sides. The organ level of organisation in animals can be first detected in flatworms and the more derived phyla , i.e. the bilaterians . The less-advanced taxa (i.e. Placozoa , Porifera , Ctenophora and Cnidaria ) do not show consolidation of their tissues into organs. More complex animals are composed of different organs, which have evolved over time. For example,

4256-484: The organ level. The 3D medium can be made using an extracellular matrix hydrogel such as Matrigel or Cultrex BME, which is a laminin -rich extracellular matrix that is secreted by the Engelbreth-Holm-Swarm tumor line. Organoid bodies can then be made through embedding stem cells in the 3D medium. When pluripotent stem cells are used for the creation of the organoid, the cells are usually, but not all

4332-514: The organ that bears the reproductive structures is called a cone . In other divisions ( phyla ) of plants, the reproductive organs are called strobili , in Lycopodiophyta , or simply gametophores in mosses . Common organ system designations in plants include the differentiation of shoot and root. All parts of the plant above ground (in non- epiphytes ), including the functionally distinct leaf and flower organs, may be classified together as

4408-477: The overall effects of an experiment on a living subject. In drug discovery , for example, verification of efficacy in vivo is crucial, because in vitro assays can sometimes yield misleading results with drug candidate molecules that are irrelevant in vivo (e.g., because such molecules cannot reach their site of in vivo action, for example as a result of rapid catabolism in the liver). The English microbiologist Professor Harry Smith and his colleagues in

4484-422: The patient's mutation in the patient iPSC cells to create an isogenic control, which can be performed simultaneously with iPSC reprogramming. Comparison of a patient iPSC derived organoid against an isogenic control is the current gold standard in the field as it permits isolation of the mutation of interest as the only variable within the experimental model. In one such report, kidney organoids derived from iPSC of

4560-439: The penetration of nutrients, the small size of organoids limits this problem. On the other hand, they do not exhibit all organ features and interactions with other organs are not recapitulated in vitro . While research on stem cells and regulation of stemness was the first field of application of intestinal organoids, they are now also used to study e.g. uptake of nutrients, drug transport and secretion of incretin hormones. This

4636-514: The phenotypic family of renal ciliopathies. Another report utilising an isogenic control demonstrated abnormal nephrin localisation in the glomeruli of kidney organoids generated from a patient with congenital nephrotic syndrome . Things such as epithelial metabolism can also be modelled. Intestinal organoids grown from rectal biopsies using culture protocols established by the Clevers group have been used to model cystic fibrosis , and led to

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4712-403: The physical forces that underlie retinal cup formation. More recent work has extended cortical organoid growth periods extensively and at nearly a year under specific differentiation conditions, the organoids persist and have some features of human fetal development stages. Organ (anatomy) An organ's tissues can be broadly categorized as parenchyma , the functional tissue, and stroma ,

4788-440: The positive role IL-22 has in maintaining in intestinal stem cells, along with demonstrating the roles of other cell types like neurons and fibroblasts in maintenance of intestinal stem cells. In the field of infection biology, different intestinal organoid-based model systems have been explored. On one hand, organoids can be infected in bulk by simply mixing them with the enteropathogen of interest. However, to model infection via

4864-670: The preclinical organoid test was subsequently confirmed upon clinical introduction of treatment by members of the clinical CF center under supervision of Kors van der Ent (Department of Paediatric Pulmonology, Wilhelmina Children's Hospital, University Medical Center Utrecht, The Netherlands). These studies show for the first time that organoids can be used for the individual tailoring of therapy or personalised medicine . The self-renewal and regenerative properties of intestinal organoids make them promising candidates for transplantation therapies, particularly for disease involving epithelial barrier disruption. Notably, transplantation of organoids into

4940-413: The relationship between the muscular and skeletal systems . In the study of anatomy , viscera ( sg. : viscus ) refers to the internal organs of the abdominal , thoracic , and pelvic cavities . The abdominal organs may be classified as solid organs or hollow organs . The solid organs are the liver , pancreas , spleen , kidneys , and adrenal glands . The hollow organs of the abdomen are

5016-534: The same germ layer . Organs exist in most multicellular organisms . In single-celled organisms such as members of the eukaryotes , the functional analogue of an organ is known as an organelle . In plants, there are three main organs. The number of organs in any organism depends on the definition used. There are approxiamately 79 Organs in the human body,but it is something that is debated as not all scientist agree on what counts as an organ. Except for placozoans , multicellular animals including humans have

5092-489: The same time, a second meaning arose, in reference to a "body part adapted to a certain function". Plant organs are made from tissue composed of different types of tissue. The three tissue types are ground, vascular, and dermal. When three or more organs are present, it is called an organ system. The adjective visceral , also splanchnic , is used for anything pertaining to the internal organs. Historically, viscera of animals were examined by Roman pagan priests like

5168-409: The shoot organ system. The vegetative organs are essential for maintaining the life of a plant. While there can be 11 organ systems in animals, there are far fewer in plants, where some perform the vital functions, such as photosynthesis , while the reproductive organs are essential in reproduction . However, if there is asexual vegetative reproduction , the vegetative organs are those that create

5244-444: The state of the field as of now through providing an abridged list of the organoids that have been successfully created, along with a brief outline based on the most recent literature for each organoid, and examples of how it has been utilized in research. A cerebral organoid describes artificially grown, in vitro , miniature organs resembling the brain . Cerebral organoids are created by culturing human pluripotent stem cells in

5320-516: The structural tissue with supportive, connective, or ancillary functions. For example, the gland 's tissue that makes the hormones is the parenchyma , whereas the stroma includes the nerves that innervate the parenchyma, the blood vessels that oxygenate and nourish it and carry away its metabolic wastes, and the connective tissues that provide a suitable place for it to be situated and anchored. The main tissues that make up an organ tend to have common embryologic origins, such as arising from

5396-443: The technique needs to be subject to a rigorous oversight procedure. In 2023, researchers have built a hybrid biocomputer that combines laboratory-grown human brain organoids with conventional circuits, and can complete tasks such as voice recognition. Cerebral Organoids are currently being used to research and develop Organoid Intelligence (OI) technologies. Gastrointestinal organoids refer to organoids that recapitulate structures of

5472-473: The temporal manipulation of the FGF , WNT , BMP , retinoic acid and EGF signalling pathways in three-dimensional culture conditions. Gastric organoids have also been generated using LGR5 expressing stomach adult stem cells . Gastric organoids have been used as model for the study of cancer along with human disease and development. For example, one study investigated the underlying genetic alterations behind

5548-722: The time, allowed to form embryoid bodies . Those embryoid bodies are then pharmacologically treated with patterning factors to drive the formation of the desired organoid identity. Organoids have also been created using adult stem cells extracted from the target organ, and cultured in 3D media. Biochemical cues have been incorporated in 3D organoid cultures and with exposure of morphogenes, morphogen inhibitors, or growth factors, organoid models can be developed using embryonic stem cells (ESCs) or adult stem cells (ASCs). Vascularization techniques can be utilized to embody microenvironments that are close to their counterparts, physiologically. Vasculature systems that can facilitate oxygen or nutrients to

5624-427: The tongue physiology. Epithelial lingual organoids have been generated using BMI1 expressing epithelial stem cells in three-dimensional culture conditions through the manipulation of EGF , WNT , and TGF-β . This organoid culture, however, lacks taste receptors , as these cells do not arise from Bmi1 expressing epithelial stem cells. Lingual taste bud organoids containing taste cells, however, have been created using

5700-414: Was observed for the first time by co-culturing keratinocytes and 3T3 fibroblasts. The phenomena of mechanically dissociated cells aggregating and reorganizing to reform the tissue they were obtained from subsequently led to the development of the differential adhesion hypothesis by Malcolm Steinberg . With the advent of the field of stem cell biology, the potential of stem cells to form organs in vitro

5776-400: Was realized early on with the observation that when stem cells form teratomas or embryoid bodies , the differentiated cells can organize into different structures resembling those found in multiple tissue types. The advent of the field of organoids, started with a shift from culturing and differentiating stem cells in two dimensional (2D) media, to three dimensional (3D) media to allow for

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