Determination of Toxicity
David Woolley, Adam Woolley in Practical Toxicology, 2017
The subject of cells in culture should not be left without considering the potential impact of stem cells. Stem cells have two properties that are attractive to the toxicologists; they reproduce themselves identically, and they can give rise to different cell types, such as heart, liver, kidney, or pancreatic islet cells. There are two basic types of stem cell–embryonic stem cells and adult stem cells, which go by a variety of names. Davila et al. (2004) carried out a review of the use of stem cells in toxicology and concluded that they have considerable potential in toxicity testing. If a range of human-derived cell lines that are similar in every respect to their tissue analogs can be produced, and if these cells can be used in assays that are reproducible, their impact could be immense. In particular, these authors single out that hepatotoxicity and cardiac effects (QT prolongation) could be beneficiaries of the use of stem cells. Although such cells have huge potential in toxicity testing, it should be remembered that the cells that are derived should be reproducible. There is little sense in deriving hepatocytes from a stem cell line on several occasions if the cells that result each time are different in subtle ways. An immortal culture of human hepatocytes that maintained its metabolic capability without change is likely to be more useful than a multiple derivation of hepatocytes from stem cells that are not the same each time.
ENTRIES A–Z
Philip Winn in Dictionary of Biological Psychology, 2003
Embryonic stem cells are able to give rise to all types of cells in the body: they are the precursors of all cells. In the adult body there are various types of stem cells—intestinal stem cells, skin stem cells and neural stem cells - that are involved in the regeneration and repair of tissues (though note that different tissues contain different amounts of stem cells: the heart for example has relatively few, the intestine a relatively large number). When stem cells divide, some of the progeny differentiate into specialized cells, others remain as stem cells. The discovery of stem cells—a recent event—has opened the possibility that neuro-degenerative diseases such as PARKINSON'S DISEASE could be treated by administration of stem cells to replace those that had been lost, though of course, whatever process was causing NEURON destruction in the first place would need to be understood and controlled to prevent the possibility of replacement cells being destroyed as the originals had been.
Tissue Engineering of Articular Cartilage
Kyriacos A. Athanasiou, Eric M. Darling, Grayson D. DuRaine, Jerry C. Hu, A. Hari Reddi in Articular Cartilage, 2017
Another possible cell source akin to progenitor populations is embryonic stem cells. While progenitor cells are highly proliferative, extensive expansion in monolayer culture can retard growth rates, shorten telomeres, and reduce multipotency (Bruder et al. 1997; Banfi et al. 2002; Baxter et al. 2004; Parsch et al. 2004; Vacanti et al. 2005). Embryonic stem cells, however, have an unlimited capacity for proliferation, and, hence, are attractive for tissue engineering endeavors that require large cell numbers (Mikos et al. 2006; Koay et al. 2007). These cells are truly pluripotent, showing a capacity to differentiate into any cell type in the body. However, researchers do not currently know the best ways to differentiate embryonic stem cells along every lineage. Some protocols have better efficacy than others, though; for example, by using established differentiation protocols, good results have been obtained for the chondrocytic lineage of human embryonic stem cells (Koay et al. 2007; Hoben et al. 2008; Koay and Athanasiou 2008, 2009; Hwang and Elisseeff 2009). As with all treatments using embryonic stem cells, there are potential problems with teratoma formation, poorly controlled cell proliferation or differentiation, and possible immunogenicity issues since the cells come from an allogeneic source. Ethical concerns have also been raised since an embryo typically has to be destroyed to establish a population of embryonic stem cells.
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.
Biological therapy for non-obstructive azoospermia
Published in Expert Opinion on Biological Therapy, 2018
Sarah C. Vij, Edmund Sabanegh, Ashok Agarwal
Ethical limitations create a significant barrier to performing the appropriate studies in humans. In the prepubertal patient population, storage of testicular tissue, SSCs, or stem cells is controversial, given the patient’s inability to provide his own consent or truly understand the implications of the procedure. Moreover, the use of embryonic stem cells is surrounded by controversy. Obtaining embryonic stem cells requires destruction of the embryo. The struggle to balance the need to cure disease with the moral obligation to protect future human life is inherent to the use of embryonic stem cells. Gene therapy for male infertility is similarly wrought with ethical concerns as manipulating the germline could have significant implications as a therapeutic option but also as a gateway to selecting characteristics to alter the genetics of populations.
Role of curcumin and its nanoformulations in the treatment of neurological diseases through the effects on stem cells
Published in Journal of Drug Targeting, 2023
Nasim Sabouni, Hadi Zare Marzouni, Sepideh Palizban, Sepideh Meidaninikjeh, Prashant Kesharwani, Tannaz Jamialahmadi, Amirhossein Sahebkar
Embryonic stem cells are pluripotent cells. They can to differentiate into all derivatives of the three lineages: ectoderm, endoderm, and mesoderm. Their excellent ability to generate partially all types of somatic cells of the adult body, such as neuronal cells, has made ESC a hopeful agent to ameliorate neurological injuries through stem cell therapy [15]. It has been demonstrated that low doses of curcumin induce the differentiation of embryonic stem cells by adjusting the nitric oxide-cyclic GMP pathway [190]. Moreover, in a study considering the effects of chemopreventive agents on the differentiation of mouse embryonic stem cells, it was found that curcumin significantly enhanced the differentiation of ESCs towards ectodermal lineages. Indeed, it could increase the expression of ectodermal transcripts at 0.4 µM [191].
Related Knowledge Centers
- Diabetes
- Fertilization
- Implantation
- Inner Cell Mass
- Embryo
- Cardiovascular Disease
- Stem Cell
- Blastocyst
- Immunosurgery
- Stem Cell Controversy