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Experimental Results on Cellular and Subcellular Systems Exposed to Low-Frequency and Static Magnetic Fields
Published in Ben Greenebaum, Frank Barnes, Biological and Medical Aspects of Electromagnetic Fields, 2018
Myrtill Simkó, Mats-Olof Mattsson
Apoptosis is a normal physiological process essential for the balanced tissue homeostasis and is thus part of cell growth. There are several lines of evidence that apoptosis and proliferation are strongly connected. Nevertheless, apoptosis can also be induced by a variety of pathologic stimuli. Differentiation is a common process whereby, e.g., stem cells divide and generate fully differentiated daughter cells during tissue repair and during normal cell turnover. Apoptosis is an important process during the differentiation process. Thus, cell proliferation, apoptosis, and differentiation are strongly connected to each other.
Principles and applications of bioprinting
Published in Ali Khademhosseini, Gulden Camci-Unal, 3D Bioprinting in Regenerative Engineering, 2018
Stem cells are defined by their ability to self-renew and produce progeny that can differentiate into specific functional cells.79–82 Stem cells are typically broken down into four types. Embryonic stem cells (ESCs) are derived from the inner cell mass of an embryo and are considered pluripotent—the ability to differentiate into all three germ layers. Second, adult stem cells exist in most tissues in the body and are generally constricted to differentiation into only the cell types that reside in that tissue. Third, perinatal stem cells (PSCs), which can be isolated from perinatal environments such as the placenta, umbilical cord, and amniotic fluid, are often considered to have plasticity somewhere between ESCs and adult stem cells. Finally, laboratory-generated, induced pluripotent stem (iPS) cells result from reprogramming terminally differentiated cells. Each of these stem cell types has advantages and disadvantages in TE and bioprinting applications. ESCs are attractive for their ability to differentiate into potentially any other cell type, thus, in theory, being able to repopulate any tissue in the human body. However, there are ethical concerns associated with procurement of ESCs, and on transplantation, they often form teratomas, thereby drastically limiting their clinical use. Adult stem cells such as bone marrow-derived mesenchymal cells (BM-MSCs) are currently being used clinically for a small set of indications and are continuing to work their way through the regulatory pathways for a variety of applications, 83,84 but their use is often restricted by limited proliferative capacity in vitro. Moreover, there is an inherent limit on differentiation potential MSCs placed on them by already being partially differentiated. iPS cells are less well characterized but have been shown to sometimes form teratomas after transplantation.85 Our laboratory has extensively explored the use of PSCs, particularly those isolated from the amniotic fluid. However, they can be isolated from additional sources, such as amniotic membrane, placenta, umbilical cord, and Wharton’s jelly.86 Unlike ESCs, FSCs carry with them no ethical concerns because their isolation does not put the developing fetus at risk. Since cells in the extraembryonic environment arise early during pregnancy may give them with a higher degree of plasticity than adult stem cells, such as BM-MSCs or adipose-derived stem cells.79 Most importantly, like MSCs, amniotic fluid-derived stem (AFS) cells, and likely other FSCs, secrete a wide range of trophic factors that are immunomodulatory and promote regeneration.75,87,88 Moreover, cells and biological compounds from the perinatal environment have recently been shown to have beneficial effects in regenerative medicine-based technologies such as wound healing and skin regeneration.43,75,89
The controlled release, bioactivity and osteogenic gene expression of Quercetin-loaded gelatin/tragacanth/ nano-hydroxyapatite bone tissue engineering scaffold
Published in Journal of Biomaterials Science, Polymer Edition, 2023
Parisa Madani, Saeed Hesaraki, Maryam Saeedifar, Navid Ahmadi Nasab
Osteogenesis is an outcome of a sequence of complicated actions containing differentiation of MSCs into osteoblasts. MSCs are mature, multipotent and can differentiate into different cells. The fate of these cells differentiation is highly dependent of the signals received from the microenvironment and is regulated by multiple pathways that activate specific transcription factors [54]. Among these factors that involve with osteogenic differentiation, Osterix or SP7 has a key role and is absolutely essential for bone homeostasis. Osteogenic differentiation goes forward through activation of cell signaling pathways including Wnt, TGF-β, BMP, FGF and Hedgehog at the early stages. At the transcription phase, there are many factors having key roles in primary and subsequent differentiation like Runx-2, Osterix, SMAPs, TCF/LEF, NFATc1, Twist, AP-1 and ATF-4. These factors do not act on their own, but have interactions and integrate different received signals and regulate gene expression [55]. Runx-2 is the first main transcription factor, which is responsible for gaining osteochondroblastic characteristics and simultaneous repression of the cells differentiation into adipocytic phenotype. Osterix belongs to the subfamily of transcription factors SP/XKLF super family and creates complexes with NFATc1 [56] that activate transcription factors relating to osteogenic genes that finally result in upregulating the expression of Col I and BGLAP (Osteocalcin).
Influence of extracellular cues of hydrogel biomaterials on stem cell fate
Published in Journal of Biomaterials Science, Polymer Edition, 2022
Haley Barnett, Mariya Shevchuk, Nicholas A. Peppas, Mary Caldorera-Moore
Advances in the field of tissue engineering have occurred in parallel with innovations in stem cell research as stem cells provide a source of self-renewing, multipotent cells for autologous treatments. The cellular component of tissue constructs is arguably one of the most challenging aspects, as the type of cell, mainly primary or stem cells, used will influence the function of the scaffold. Primary cells are fully differentiated cells that are harvested from tissue-specific locations [9] while stem cells retain self-renewal capabilities and have the ability to differentiate into multiple cell types [10]. The determination of which cell type is better suited will vary from application to application. For example, primary cells are harvested from autologous tissue, which may not be feasible in severely damaged tissue or for some cell types such as spinal cord neurons. By contrast, stem cells can be isolated from embryos or from adult tissue, and can be differentiated into a range of phenotypes, making them a virtually limitless cell source [9]. Therefore, recent tissue engineering strategies have focused on the use of stem cells and on promoting the differentiation of these cells to specific lineages.
Comparing hydroxyapatite with osteogenic medium for the osteogenic differentiation of mesenchymal stem cells on PHBV nanofibrous scaffolds
Published in Journal of Biomaterials Science, Polymer Edition, 2019
Lan-Xin Lyu, Xiao-Feng Zhang, Anthony J. Deegan, Gao-Feng Liang, Hong-Ning Yang, Shu-Qun Hu, Xian-Liang Yan, Ning-Ping Huang, Tie Xu
Directional differentiation of MSCs plays a vital role in tissue engineering. Besides chemical regents, MSCs can also be induced down different cell linages by culture substrate stiffness, topography, and chemical groups [24,25]. In our previous studies, we investigated substrate influences and found that both HA-NF and stretched inversed opal films could induce osteogenic differentiation of MSCs though BMP-Smad and MAPK signaling pathways in the absence of OIM [11,26]. Yi Deng et al. found that PPS/Nano-HA composites evoked better osteo-differentiation on account of the contribution of the doped nano-HA [9]. Yicong Zuo et al. demonstrated that GelMA-HA composite hydrogel system could enhance osteogenesis of human osteoblast-like cells [10]. These studies, involved with three substrates with various stiffness, indicated that HA rather than substrate stiffness plays the main effect on osteogenesis and the mechanism underneath needs to be revealed. Zhiwei Zhang and his group have reported the pure HA disc effect on osteogenesis of MSCs through ERK1/2 or JNK MAPK pathways [2]. According to Lixin Wang’s study, PEEK/HA with rough surface can induce higher ALP activity and mineralization of human osteoblast-like MG-63 cells, indicating that surface roughness could act as a promoter of osteogenic differentiation [8].