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Nanotechnology in Stem Cell Regenerative Therapy and Its Applications
Published in Harishkumar Madhyastha, Durgesh Nandini Chauhan, Nanopharmaceuticals in Regenerative Medicine, 2022
Totipotent stem cells are competent to form a whole organism such as a zygote. They possess an incredible ability to extend into germ cell layers of the embryonic and extra-embryonic tissues, thus shaping into embryo and placenta (Rossant 2001). Totipotent cells originate from the early development stage, and these undifferentiated cells can develop into any type of cells further.
Dentin-Pulp Complex Regeneration
Published in Vincenzo Guarino, Marco Antonio Alvarez-Pérez, Current Advances in Oral and Craniofacial Tissue Engineering, 2020
Amaury Pozos-Guillén, Héctor Flores
All tissues originate from stem cells, which play an indispensable role in embryonic development and tissue regeneration. These cells are capable of self-renewal, proliferation, and differentiation into multiple mature cell types. Stem cell potency describes the potential of the cell to divide and express different cell phenotypes. Totipotent stem cells are able to divide and produce all the cells in an individual. Pluripotent stem cells have not completely divided and can become many cells, but not all lineages. They are able to differentiate into any of the three germ layers: endoderm, mesoderm or ectoderm, where the progeny has multiple distinct phenotypes, whilst multipotent stem cells can differentiate into cells from multiple, but a limited number of lineages (Robey 2000).
Cell structure, function and adaptation
Published in C. Simon Herrington, Muir's Textbook of Pathology, 2020
An extension of this work, with important ethical implications, is the use of near-totipotent stem cells derived from human embryos fertilized in vitro. Basic genetic research is addressing how stem cells are controlled and, in particular, how many classes of gene can be switched on or off depending on differentiation status. This has led to the development of cloning, where a single nucleus from a differentiated cell can be conditioned to behave like a totipotent fertilized germ cell and give rise to a genetically identical offspring. This requires the pseudo-fertilization stimulation of a nucleus inserted into the empty cytoplasm of an ovum. To date, cloned progeny include sheep (e.g. Dolly), cats, and mice. There is a high loss of embryos due to malformation, and the effects on ageing and disease susceptibility are being studied to determine whether the cloned animals retain the memory of their originating cell's ‘age’, or whether their replicative clock is reset to zero.
Spermatogonial stem cell transplantation and male infertility: Current status and future directions
Published in Arab Journal of Urology, 2018
Connor M. Forbes, Ryan Flannigan, Peter N. Schlegel
Stem cells are defined as cells with the ability to make copies of themselves indefinitely (self-renewal), and also with the ability to differentiate into other cell types [9]. Totipotent stem cells can differentiate into all cell types including extra-embryonal cells, whilst pluripotent cells can differentiate into every cell in the human body but not extra-embryonal cells [9]. Multipotent cells can differentiate into multiple cell types within one germ layer, and unipotent cells can differentiate into several or only one cell type [10].
Treating childhood traumatic brain injury with autologous stem cell therapy
Published in Expert Opinion on Biological Therapy, 2018
Shyam Dewan, Samantha Schimmel, Cesar V. Borlongan
Stem cells are undifferentiated cells that can replicate even after periods of inactivity and can be induced to become cells with specific functions such as tissue cells and organ-specific cells [4,5]. The unique properties of stem cells provide the basis for their use as transplantable cells in treating many conditions and diseases. The most common form of stem cell therapy is the use of blood stem cells derived from the bone marrow to treat diseases and conditions of the blood and immune system [4]. Types of stem cells include embryonic, fetal, neonatal (e.g. placenta, umbilical cord blood and tissues, amnion fluid and tissues, Wharton jelly), and adult tissues [1–3]. Embryonic stem cells are derived from the inner cell mass of a blastocyst, an early stage of embryonic development [4]. Adult stem cells are undifferentiated somatic cells found throughout the body that remain undifferentiated to replenish dying and damaged tissues; an example is cells in the bone marrow [4]. Induced pluripotent stem cells are produced from differentiated somatic cells, which when exposed to stem cell inducing elements (i.e. oncogenic factors) can revert to naive cells with stem cell properties [4]. Stem cells can also fall into the categories of totipotent, pluripotent, and multipotent. Totipotent stem cells can divide and specialize into any body cell, while pluripotent stem cells can differentiate into any of the three germ layers: endoderm, mesoderm, and ectoderm [4,5]. Multipotent stem cells have more limited differentiation potential, able to differentiate into many cells of one tissue, such as differentiation into multiple blood cells or different nervous cells [4]. Additionally, different approaches to transplant stem cells in CNS disorders have been investigated. Autologous transplantation refers to a process by which stem cells are harvested from a patient and later returned to the patient for treatment [1,4]. Allogeneic transplants differ in that stem cells are harvested from a donor (with similar immune system markers to the recipient) and transplanted to the recipient [1,4]. Closely related family members are often the most effective allogeneic donors because their immune systems are the most similar to the recipients [1,4]. Xenogeneic transplants are similar to allogeneic transplants in that there is a mismatch in the donor and the recipient, but xenogeneic transplants involve a donor of a different species than the recipient [1,4].