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Recombinant DNA Technology and Gene Therapy Using Viruses
Published in Patricia G. Melloy, Viruses and Society, 2023
As mentioned in the introduction, induced pluripotent stem cells (iPSCs) are a type of stem cell made by reprogramming adult cells to behave like stem cells. Early work on iPSCs involved using a retroviral-based vector to express a set of genes that turn the clock back on the adult cell nucleus, making it behave like a stem cell present back in early development of the organism. (Alberts et al. 2019; Clarke and Frampton 2020; Kurreck and Stein 2016). Researchers are also working to use adenoviral-based vectors to make iPSCs as well (Stadtfeld et al. 2008). Stem cells are important for regenerative medicine due to their potential to form many cell types of the body, not just one specialized kind. The goal of regenerative medicine is to replace tissues that are affected by disease or worn out with age. Future research will involve further fine-tuning of the iPSC approach to see if these cells can be effectively used to treat patients. Beyond making pluripotent stem cells themselves, researchers are also developing adenoviral vectors to express certain growth factors needed in the tissue specialization process, such as to make bone, to make particular tissues for regenerative purposes (Lee et al. 2017).
Stem cell biology
Published in Christine Hauskeller, Arne Manzeschke, Anja Pichl, The Matrix of Stem Cell Research, 2019
Closely related to the adult/embryonic distinction is the classification of stem cells in terms of ‘potency’. Cognates of this term are qualitative descriptions of the range of mature (specialized) cell types that a given stem cell can give rise to by differentiation (accompanied by cell division). Maximum developmental potential is referred to as totipotency: the capacity to produce an entire organism (and, in mammals, extra-embryonic tissues). In animals, totipotency is limited to the fertilized egg and products of early cell divisions. In the nineteenth and early twentieth century, the term ‘stem cell’ often referred to totipotent cells of early development (Dröscher, 2014). But this usage is no longer standard. The maximum developmental potential for stem cells as the term is used today is pluripotency: the ability to produce all cell types of an adult organism. More restricted stem cells are multipotent: able to produce some, but not all, mature cell types. Stem cells that can give rise to only a few mature cell types are oligopotent. Minimum differentiation potential is unipotency: the capacity to produce only a single cell type. The rough ordering of ‘potencies’ offers a generic way of classifying stem cells. Pluripotent stem cells are the focus of much stem cell research, as they can serve as sources of stem cells with more restricted developmental potential. For example, multipotent hematopoietic or neural stem cells can be produced by differentiation from pluripotent stem cells.
Natural Products and Stem Cells and Their Commercial Aspects in Cosmetics
Published in Heather A.E. Benson, Michael S. Roberts, Vânia Rodrigues Leite-Silva, Kenneth A. Walters, Cosmetic Formulation, 2019
Sonia Trehan, Rose Soskind, Jemima Moraes, Vinam Puri, Bozena Michniak-Kohn
The two main types of stem cells from animals and humans, that have been worked on in the recent times are embryonic and non-embryonic stem cells. Embryonic stem cells are those that are derived from a 5-day preimplantation embryo. These are pluripotent cells that can grow into cells or tissues of any of the three germ layers – ectoderm, mesoderm and endoderm. These can be cultured in vitro to allow proliferation without differentiation for a long time. Non-embryonic stem cells, also known as somatic or adult stem cells are found in organs and differentiated tissues, and have shown to possess limited ability to differentiate and self-renew. Another type of stem cell is induced pluripotent stem cells (iPSCs) that are somatic cells reprogrammed to assume an embryonic stem cell–like state.
Functional role of ascorbic acid in the central nervous system: a focus on neurogenic and synaptogenic processes
Published in Nutritional Neuroscience, 2022
Morgana Moretti, Ana Lúcia S. Rodrigues
Embryonic stem cells are pluripotent cells isolated from the inner cell mass of an early-stage blastocyst [25]. Embryonic stem cells self-renew by dividing and can differentiate into specialized cells, including neurons, oligodendrocytes, and astrocytes [26]. Induced pluripotent stem cells (iPSCs) are pluripotent stem cells generated from adult cells by reprogramming. iPSCs have the same properties as embryonic stem cells, and therefore self-renew and can differentiate into all cell types [27]. It was reported that ascorbic acid improved the speed and efficiency of the generation of mouse and human iPSCs from somatic cells. The increase in the number of iPSCs was dependent on the reduction of p53 levels, the tumor suppressor protein that triggers apoptosis via multiple pathways [28]. In the presence of ascorbic acid, in vitro cultured cells express Jhdm1a/1b, two histone demethylases required for iPSCs production [29]. It was also reported that ascorbic acid markedly increases glial proliferation, neurite growth, and the number of tyrosine hydroxylase staining in mesencephalic cultures [30]. Collectively, these results suggest that vitamin C can regulate positively stem cell generation and proliferation.
Uncontrolled Oxygen Levels in Cultures of Retinal Pigment Epithelium: Have We Missed the Obvious?
Published in Current Eye Research, 2022
For cultures of RPE, cells are either obtained from dissected living tissue or cell lines. Early successful works began with embryonic chicks3 in the 1920th and extended to other non-human species (amphibians and animals) thereafter.4 From the 1960s, notable progress in cell culture technique, especially development of Eagle’s medium,44 has facilitated such in vitro studies. Since the 1970s, human RPE cultures, the best model system, have been in use. Currently two forms of them, fetal and adult, are in practice.45 However, obstacles including ethical considerations and limited access to human donors have encouraged the continuation of using human pluripotent stem cells as well as cells from non-human sources.4 The induced pluripotent stem cell-derived RPE (iPSC-RPE) is a promising alternative to human RPE for various applications such as genetic studies 46 and the development of cell-based regenerative therapies.47 It non-invasively yields unlimited number of cells with the same genetic background.46 Regarding non-human origin, one example is adult porcine RPE cells that can be used easily by bypassing ethical issues, postmortem time and accessibility/age of donors. Although these cells largely resemble adult human RPE cell culture, the porcine eye lacks macula or fovea.45
Bacteria and cells as alternative nano-carriers for biomedical applications
Published in Expert Opinion on Drug Delivery, 2022
Rafaela García-Álvarez, María Vallet-Regí
Up to the 20th century, medical procedures, such as blood transfusion, assisted fertility, or organ transplantation, have become common, as well as using functional tissue for treatment of several diseases. However, the use of donor tissue to treat medical problems was limited to like for like, for instance: blood for blood or skin for skin tissues until the beginning of the 21st century. This paradigm changed with the discovery and description of the ‘stem cells’ by Ernest McCulloch and James Till in the early 1960s [114]. Pluripotent stem cells have the potential of differentiating into many or any tissue type, which can nowadays be achieved owing to the development of the necessary tools for this purpose. These particular cell type is known to be a constituent of embryonic tissue and bone marrow, tissues that are particularly expensive and difficult to obtain. Due to their origin, stem cell use raises some ethical and legal questions regarding their collection and their utilization for commercial purposes [115]. Fortunately, these cells were acknowledged in another kind of tissue, which provided an alternative for the collection, manipulation, and potential use of stem cells – or other different types of undifferentiated cells – for alternative therapies avoiding the need of embryonic or bone marrow materials [116]. This leads to the possibility of commercialization at large scale of cell-therapy products.