Next Generation Tissue Engineering Strategies by Combination of Organoid Formation and 3D Bioprinting
Naznin Sultana, Sanchita Bandyopadhyay-Ghosh, Chin Fhong Soon in Tissue Engineering Strategies for Organ Regeneration, 2020
Another significant event during embryogenesis is gastrulation that involves patterning of pluripotent epiblast into the three germ layers that later develops into the embryo. This event involves a signaling pathway involving the BMP, Wnt and Nodal pathways (Chhabra et al. 2018). Thus, replication of such events seems quintessential to the approach of developmental biology inspired tissue engineering strategies (Fig. 4.2). This section would be incomplete without the mention of another interesting phenomenon of developmental biology, that is, directed tissue assembly, a process where closely placed tissue spheroids undergo fusion to replicate this fundamental biophysical and biological principle of directed tissue assembly (Mironov et al. 2009). Tissue engineers tried to take cues from this process and incorporated those features with 3D bioprinting, that led to the emergence of the new field of organ printing that holds promise to design and fabricate engineered tissue/mini organs for repair, regeneration and replacement of injured or damaged organs. One of our studies represents a true example of such an approach, where we first developed 3D spheroids of MSCs and chondrocytes for successful replication of mesenchymal condensation involving cell-cell adhesion formation through neural cell adhesion molecule (NCAM). These spheroids probably provided in vivo like microenvironment for development of stable cartilage tissue equivalent. Then these spheroids were combined with silk-gelatin hydrogel to develop 3D bioprinted cartilage tissue equivalents (Chameettachal et al. 2016) (Fig 4.3).
Current developments in human stem cell research and clinical translation
Christine Hauskeller, Arne Manzeschke, Anja Pichl in The Matrix of Stem Cell Research, 2019
After the implantation of the blastocyst on days 7–9 the ICM develops into the epiblast (De Paepe et al., 2014). Epiblast stem cells are still pluripotent but as they have undergone more developmental stages they are referred to as primed pluripotent stem cells to distinguish them from naïve pluripotent stem cells of the pre-implantation ICM (Boroviak and Nichols, 2014). Epiblast stem cells lose their pluripotency when a thickened structure, called the primitive streak, is formed along the midline of the epiblast, which at this stage defines the body axes and orientations of the future embryo: cranial (head) versus caudal (feet), anterior (front) versus posterior (back), as well as left versus right end. During this process (known as gastrulation) the single-layered epiblast is reorganized into a three-layered gastrula forming the three germ layers: ectoderm (outer layer), mesoderm (middle layer), and endoderm (inner layer).
Fertilization and normal embryonic and early fetal development
Hung N. Winn, Frank A. Chervenak, Roberto Romero in Clinical Maternal-Fetal Medicine Online, 2021
Along with the implantation process, changes occur in the embryoblast to produce a bilaminar embryonic disc, composed of the epiblast and the hypoblast. Early in the 2nd week, the amniotic cavity appears as a space lined with amnioblasts derived from the epiblast. By the end of the 2nd week, the embryonic disc becomes oval in shape. Along the median line in the posterior region of the embryonic disc, a thickening of the epiblast called the primitive streak appears, and it defines the longitudinal axis of the embryo. During the 3rd week, lateral epiblast cells migrate medially, enter the primitive streak, and then converge to form the primitive groove.
Split cord malformation associated with congenital dermoid cyst and myeloschisis – case-based literature review on possible embryonic derivation and implications
Published in British Journal of Neurosurgery, 2020
Suhas Udayakumaran, Chiazor U. Onyia
We try to explain this unusual presentation based on previous theories in the literature. From the discussion, two conclusions may be drawn. First, these anomalies involve all three primary germ layers and therefore, they share a common embryonic origin from the epiblast. Secondly, they likely occurred as a result of abnormal ecto-endodermal adhesion between the yolk sac and amnion. Thus, theory of notochordal splitting and endomesechymal tract formation consequent on endodermal-ectodermal adhesion as postulated by Beardmore and Wigglesworth appears to be the most plausible explanation. Interestingly however, the theory suggesting disordered gastrulation proposed by Dias and Walker on related embryopathy is a more recent explanation than notochordal splitting and endomesechymal tract formation by Beardmore and Wigglesworth.23,26,27 This hence suggests that these currently accepted theories on pathologies of development during intrauterine life may still fall short of fully explaning a few rare exceptions such as observed with our two patients. However, we acknowledge that our deductions may not be entirely accurate and further studies of such embryopathy may explain the occurrence more accurately than existing theories.
Application of amniotic membrane in reconstructive urology; the promising biomaterial worth further investigation
Published in Expert Opinion on Biological Therapy, 2019
Jan Adamowicz, Shane Van Breda, Dominik Tyloch, Marta Pokrywczynska, Tomasz Drewa
The mammalian embryo is enclosed in the fluid filed amniotic sac of the placenta, surrounded by the AM. In humans, 6–7 days after fertilization, AM starts to develop during blastocyst implantation in the endometrium [6]. Subsequently, the embryoblast (inner cell mass within the blastocyst) differentiates into a bilaminar disc composed of the hypoblast and epiblast. Eventually, amnioblasts derived from the epiblast invade the space between the trophoblast and the embryonic disc, migrating to the inner amniotic layer and gradually constitute the external lining of the amniotic cavity. The amniotic and chorionic fetal membranes separate the embryo from the endometrium. The amniochorionic membrane forms the outer limits of the sac that encloses the embryo, while the innermost layer of the sac is the AM [7].
The role of stem cells in cystic fibrosis disease modeling and drug discovery
Published in Expert Opinion on Orphan Drugs, 2018
Massimo Conese, Elisa Beccia, Annalucia Carbone, Stefano Castellani, Sante Di Gioia, Fabiola Corti, Antonella Angiolillo, Carla Colombo
The isolation of MSCs from bone marrow is not devoid of risks, such as morbidity at the donor site and the limited number of MSCs obtained [75]. As an alternative, MSCs can be isolated from other more fruitful and ethical sources. The placenta is an organ discarded after childbirth. However, it contains cells which derive early in the embryo i.e. amnioblasts, deriving from the pluripotent epiblast [76]. Moreover, their yield upon isolation is high and they can be easily expanded and passaged. Amniotic and chorionic membranes, as well as the trophoblast, contain such cells. As far as the amniotic membrane is concerned, we focused on MSCs because of their antibacterial and immune-suppressive properties, which could be useful in therapeutic approaches to CF [77]. As in the case of iPSCs, their effects should not be class mutation dependent (Figure 1).
Related Knowledge Centers
- Ectoderm
- Endoderm
- Germ Layer
- Hypoblast
- Inner Cell Mass
- Mesoderm
- Embryo
- Blastocyst
- Animal Embryonic Development
- Blastulation