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Author

Georg Bartsch

Other affiliations: Boston Children's Hospital
Bio: Georg Bartsch is an academic researcher from Wake Forest Institute for Regenerative Medicine. The author has contributed to research in topics: Amniotic stem cells & Amniotic epithelial cells. The author has an hindex of 4, co-authored 5 publications receiving 2157 citations. Previous affiliations of Georg Bartsch include Boston Children's Hospital.

Papers
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Journal ArticleDOI
TL;DR: The isolation of human and rodent amniotic fluid–derived stem (AFS) cells that express embryonic and adult stem cell markers are reported and examples of differentiated cells derived from human AFS cells and displaying specialized functions include neuronal lineage cells secreting the neurotransmitter L-glutamate or expressing G-protein-gated inwardly rectifying potassium channels.
Abstract: Stem cells capable of differentiating to multiple lineages may be valuable for therapy. We report the isolation of human and rodent amniotic fluid-derived stem (AFS) cells that express embryonic and adult stem cell markers. Undifferentiated AFS cells expand extensively without feeders, double in 36 h and are not tumorigenic. Lines maintained for over 250 population doublings retained long telomeres and a normal karyotype. AFS cells are broadly multipotent. Clonal human lines verified by retroviral marking were induced to differentiate into cell types representing each embryonic germ layer, including cells of adipogenic, osteogenic, myogenic, endothelial, neuronal and hepatic lineages. Examples of differentiated cells derived from human AFS cells and displaying specialized functions include neuronal lineage cells secreting the neurotransmitter L-glutamate or expressing G-protein-gated inwardly rectifying potassium channels, hepatic lineage cells producing urea, and osteogenic lineage cells forming tissue-engineered bone.

1,843 citations

Book ChapterDOI
TL;DR: A subset of cells found in amniotic fluid and placenta has been isolated and found to be capable of maintaining prolonged undifferentiated proliferation as well as able to differentiate into multiple tissue types encompassing the three germ layers.
Abstract: Human amniotic fluid has been used in prenatal diagnosis for more than 70 years. It has proven to be a safe, reliable, and simple screening tool for a wide variety of developmental and genetic diseases. However, there is now evidence that amniotic fluid may have more use than only as a diagnostic tool and may be the source of a powerful therapy for a multitude of congenital and adult disorders. A subset of cells found in amniotic fluid and placenta has been isolated and found to be capable of maintaining prolonged undifferentiated proliferation as well as able to differentiate into multiple tissue types encompassing the three germ layers. It is possible that in the near future, we will see the development of therapies using progenitor cells isolated from amniotic fluid and placenta for the treatment of newborns with congenital malformations as well as of adults, using cryopreserved amniotic fluid and placental stem cells. In this chapter, we describe a number of experiments that have isolated and characterized pluripotent progenitor cells from amniotic fluid and placenta. We also discuss various cell lines derived from amniotic fluid and placenta and future directions for this area of research.

241 citations

Journal ArticleDOI
15 Dec 2002-Blood
TL;DR: Results demonstrate that angiogenic factors such as VEGF promote AML progression in vivo and offer a potential treatment for AML, and a novel in vivo drug delivery model may be useful for testing the activities of other peptide antiangiogenic Factors.

150 citations

Journal ArticleDOI
TL;DR: It is affirm that stem cells capable of extensive self-renewal can routinely be obtained from human amniotic fluid and that AFS cells are pluripotent stem cells.
Abstract: Amniotic fluid contains multiple cell types derived from the developing fetus, including some that can give rise to differentiated adipose, muscle, bone, and neuronal cell lines. The present investigators have identified lines of broadly multipotent amniotic fluid-derived stem (AFS) cells that can give rise to a wide range of lineages including those in all embryonic germ layers, thereby meeting the criterion for pluripotent stem cells. Immunoselection with magnetic microspheres was used to isolate, from cultures of human amniocentesis specimens taken for prenatal genetic diagnosis, cells bearing the surface antigen c-Kit, the receptor for stem cell factor. Flow cytometry served to assess markers expressed by human AFS cells. AFS cells from 19 amniocentesis donors were able to differentiate along adipogenic, osteogenic, myogenic, endothelial, neurogenic, and hepatic pathways. Induced differentiation along multiple pathways was documented by the expression of mRNAs for lineage-specific genes. Multilineage differentiation was characteristic of AFS cells that were cloned by limiting dilution. Studies based on marking with a retroviral vector confirmed that cloned AFS cells and their differentiated derivatives did in fact descend from a single cell, and that the AFS cells are pluripotent stem cells. Feeders were not necessary for the undifferentiated AFS cells to expand extensively. The cells doubled in 36 hours and were not tumorigenic. Lines maintained for more than 250 population doublings continued to have long telomeres and normal karyotypes. The differentiated cells derived from AFS cells included neuronal lineage cells secreting the neurotransmitter L-glutamate or expressing G-protein-gated inwardly rectifying potassium channels, hepatic lineage cells producing urea, and osteogenic lineage cells that formed tissue-engineered bone. These studies affirm that stem cells capable of extensive self-renewal can routinely be obtained from human amniotic fluid. AFS cells can serve as precursors to a broad range of differentiated cell types that potentially have therapeutic applications. Banking of cells that would otherwise be discarded could provide a convenient source not only for autologous treatment later in life, but for matching of histocompatible donor cells with prospective recipients.

66 citations

Book ChapterDOI
01 Jan 2002

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Journal ArticleDOI
TL;DR: 3D bioprinting is being applied to regenerative medicine to address the need for tissues and organs suitable for transplantation and developing high-throughput 3D-bioprinted tissue models for research, drug discovery and toxicology.
Abstract: Additive manufacturing, otherwise known as three-dimensional (3D) printing, is driving major innovations in many areas, such as engineering, manufacturing, art, education and medicine. Recent advances have enabled 3D printing of biocompatible materials, cells and supporting components into complex 3D functional living tissues. 3D bioprinting is being applied to regenerative medicine to address the need for tissues and organs suitable for transplantation. Compared with non-biological printing, 3D bioprinting involves additional complexities, such as the choice of materials, cell types, growth and differentiation factors, and technical challenges related to the sensitivities of living cells and the construction of tissues. Addressing these complexities requires the integration of technologies from the fields of engineering, biomaterials science, cell biology, physics and medicine. 3D bioprinting has already been used for the generation and transplantation of several tissues, including multilayered skin, bone, vascular grafts, tracheal splints, heart tissue and cartilaginous structures. Other applications include developing high-throughput 3D-bioprinted tissue models for research, drug discovery and toxicology.

4,841 citations

Journal ArticleDOI
TL;DR: An integrated tissue–organ printer (ITOP) that can fabricate stable, human-scale tissue constructs of any shape is presented and the incorporation of microchannels into the tissue constructs facilitates diffusion of nutrients to printed cells, thereby overcoming the diffusion limit of 100–200 μm for cell survival in engineered tissues.
Abstract: A challenge for tissue engineering is producing three-dimensional (3D), vascularized cellular constructs of clinically relevant size, shape and structural integrity. We present an integrated tissue-organ printer (ITOP) that can fabricate stable, human-scale tissue constructs of any shape. Mechanical stability is achieved by printing cell-laden hydrogels together with biodegradable polymers in integrated patterns and anchored on sacrificial hydrogels. The correct shape of the tissue construct is achieved by representing clinical imaging data as a computer model of the anatomical defect and translating the model into a program that controls the motions of the printer nozzles, which dispense cells to discrete locations. The incorporation of microchannels into the tissue constructs facilitates diffusion of nutrients to printed cells, thereby overcoming the diffusion limit of 100-200 μm for cell survival in engineered tissues. We demonstrate capabilities of the ITOP by fabricating mandible and calvarial bone, cartilage and skeletal muscle. Future development of the ITOP is being directed to the production of tissues for human applications and to the building of more complex tissues and solid organs.

1,960 citations

Journal ArticleDOI
15 Nov 2007-Blood
TL;DR: The aim of this review is to critically discuss the immunogenicity and immunomodulatory properties of MSCs, both in vitro and in vivo, the possible underlying mechanisms, the potential clinical use of M SCs as modulators of immune responses in vivo and to indicate clinical safety concerns and recommendations for future research.

1,683 citations

Journal ArticleDOI
22 Feb 2008-Cell
TL;DR: In this article, the authors review strategies to reprogram somatic cells to a pluripotent embryonic state and discuss their understanding of the molecular mechanisms of reprogramming based on recent insights into the regulatory circuitry of the PLSTM.

1,450 citations

Journal ArticleDOI
TL;DR: MSC derived from different adult and neonatal tissues are compared with respect to their cell biological properties, surface marker expression and proliferative capacities and several MSC functions including in vitro and in vivo differentiation capacities within a variety of lineages and immune-modulatory properties are highlighted.
Abstract: The mesenchymal stroma harbors an important population of cells that possess stem cell-like characteristics including self renewal and differentiation capacities and can be derived from a variety of different sources. These multipotent mesenchymal stem cells (MSC) can be found in nearly all tissues and are mostly located in perivascular niches. MSC have migratory abilities and can secrete protective factors and act as a primary matrix for tissue regeneration during inflammation, tissue injuries and certain cancers. These functions underlie the important physiological roles of MSC and underscore a significant potential for the clinical use of distinct populations from the various tissues. MSC derived from different adult (adipose tissue, peripheral blood, bone marrow) and neonatal tissues (particular parts of the placenta and umbilical cord) are therefore compared in this mini-review with respect to their cell biological properties, surface marker expression and proliferative capacities. In addition, several MSC functions including in vitro and in vivo differentiation capacities within a variety of lineages and immune-modulatory properties are highlighted. Differences in the extracellular milieu such as the presence of interacting neighbouring cell populations, exposure to proteases or a hypoxic microenvironment contribute to functional developments within MSC populations originating from different tissues, and intracellular conditions such as the expression levels of certain micro RNAs can additionally balance MSC function and fate.

1,369 citations