Displaying publications 1 - 20 of 397 in total

  1. Wong RSY
    Hum Immunol, 2015 Oct;76(10):781-8.
    PMID: 26429327 DOI: 10.1016/j.humimm.2015.09.038
    Spondyloarthritis (SpA) is a family of interrelated inflammatory arthritis that includes ankylosing spondylitis (AS), psoriatic arthritis, reactive arthritis, arthritis related to inflammatory bowel disease and undifferentiated SpA. The classification, epidemiology, pathogenesis and treatment of SpA have been extensively reviewed in the published literature. Reviews on the use of stem cells in various autoimmune diseases in general are also common. However, a review on the role of stem cells in SpA is currently lacking. This review focuses on the involvement of stem cells in the pathogenesis of SpA and the application of different types of stem cells in the treatment of SpA. It also addresses some of the complications which may arise as a result of the use of stem cells in the treatment of SpA.
    Matched MeSH terms: Stem Cells
  2. Sung TC, Su HC, Ling QD, Kumar SS, Chang Y, Hsu ST, et al.
    Biomaterials, 2020 09;253:120060.
    PMID: 32450407 DOI: 10.1016/j.biomaterials.2020.120060
    The current differentiation process of human pluripotent stem cells (hPSCs) into cardiomyocytes to enhance the purity of hPSC-derived cardiomyocytes requires some purification processes, which are laborious processes. We developed cell sorting plates, which are prepared from coating thermoresponsive poly(N-isopropylacrylamide) and extracellular matrix proteins. After hPSCs were induced into cardiomyocytes on the thermoresponsive surface coated with laminin-521 for 15 days, the temperature of the cell culture plates was decreased to 8-9 °C to detach the cells partially from the thermoresponsive surface. The detached cells exhibited a higher cardiomyocyte marker of cTnT than the remaining cells on the thermoresponsive surface as well as the cardiomyocytes after purification using conventional cell selection. The detached cells expressed several cardiomyocyte markers, such as α-actinin, MLC2a and NKX2.5. This study suggested that the purification of hPSC-derived cardiomyocytes using cell sorting plates with the thermoresponsive surface is a promising method for the purification of hPSC-derived cardiomyocytes without conventional laborious processes.
    Matched MeSH terms: Pluripotent Stem Cells*; Induced Pluripotent Stem Cells*
  3. Nordin N, Lai MI, Veerakumarasivam A, Ramasamy R, Abdullah S, Wendy-Yeo WY, et al.
    Med J Malaysia, 2011 Mar;66(1):4-9.
    PMID: 23765134 MyJurnal
    The development of induced pluripotent stem cells (iPSCs) has been met with much enthusiasm and hailed as a breakthrough discovery by the scientific and research communities amidst the divisive and ongoing debates surrounding human embryonic stem cells (hESC) research. The discovery reveals the fact that embryonic pluripotency can be generated from adult somatic cells by the induction of appropriate transcriptional factor genes essential for maintaining the pluripotency. They provide an alternative source for pluripotent stem cells, thus representing a powerful new research tool besides their potential application in the field of regenerative medicine. In this review, the historical background of iPSCs generation will be discussed together with their properties and characteristics as well as their potential therapeutic applications.
    Matched MeSH terms: Induced Pluripotent Stem Cells*
  4. Padma Priya S, Higuchi A, Abu Fanas S, Pooi Ling M, Kumari Neela V, Sunil PM, et al.
    Lab Invest, 2015 Dec;95(12):1344-52.
    PMID: 26367485 DOI: 10.1038/labinvest.2015.108
    The ultimate goal of dental stem cell research is to construct a bioengineered tooth. Tooth formation occurs based on the well-organized reciprocal interaction of epithelial and mesenchymal cells. The dental mesenchymal stem cells are the best explored, but because the human odontogenic epithelium is lost after the completion of enamel formation, studies on these cells are scarce. The successful creation of a bioengineered tooth is achievable only when the odontogenic epithelium is reconstructed to produce a replica of natural enamel. This article discusses the untapped sources of odontogenic epithelial stem cells in humans, such as those present in the active dental lamina in postnatal life, in remnants of dental lamina (the gubernaculum cord), in the epithelial cell rests of Malassez, and in reduced enamel epithelium. The possible uses of these stem cells in regenerative medicine, not just for enamel formation, are discussed.
    Matched MeSH terms: Stem Cells*
  5. Chin JJ
    Med J Malaysia, 2003 Mar;58 Suppl A:111-8.
    PMID: 14556358
    Like most cutting edge medical technology, human stem cell research raises a number of difficult and important ethical issues and concerns, requiring potential benefits to be balanced against the need to protect the rights and welfare of citizens. Much of the debate involves research using embryonic stem (ES) cells, which in turns revolves around the moral status of the human embryo, and the level of respect and protection that should be accorded. This is an especially sensitive issue in pluralistic societies where different, if not conflicting, cultural and religious perspectives exist. Another contentious issue as far as the derivation of ES cells is concerned is the intent involved in producing the embryos, specifically whether it is ethically permissible to allowing embryos to be made solely for the purpose of research. These and several other relevant ethical issues will be discussed, including a comparison of guidelines and positions adopted in different countries.
    Matched MeSH terms: Stem Cells*
  6. Ali F, Taresh S, Al-Nuzaily M, Mok PL, Ismail A, Ahmad S
    Eur Rev Med Pharmacol Sci, 2016 Oct;20(20):4390-4400.
    PMID: 27831631
    Numerous lines of evidence support that bone marrow is a rich source of stem cells that can be used for research purposes and to treat some complex blood diseases and cancers. Stem cells are a potential source for regenerative medicine and tissue replacement after injury or disease, and mother cells that possess the capacity to become any type of cell in the body. They are cells without specific structure and characterized by their ability to self-renew or multiply while maintaining the potential to develop into other types of cells. Stem cells can normally become cells of the blood, heart, bones, skin, muscles or brain. Although, there are different sources of stem cells, all types of stem cells have the same capacity to develop into multiple types of cells. Stem cells are generally described as unspecialized cells with unlimited proliferation capacity that can divide (through mitosis) to produce more stem cells. Several types of adult stem cells have been characterized and can be cultured in vitro, including neural stem cells, hematopoietic stem cells, mesenchymal stem cells, cardiac stem cells and epithelial stem cells. They are valuable as research tools and might, in the future, be used to treat a wide range of diseases such as hematological hereditary diseases, Parkinson's disease, diabetes mellitus, heart disease and many other diseases. Currently, two types of stem cells have been identified based on their origins, namely embryonic stem cells and adult stem cells. Collectively, although many kinds of literature have been studying stem cell application in terms of clinical practice, stem cell-based therapy is still in its infancy stage.
    Matched MeSH terms: Stem Cells/cytology; Embryonic Stem Cells; Adult Stem Cells*
  7. Heng BC, Jiang S, Yi B, Gong T, Lim LW, Zhang C
    Arch Oral Biol, 2019 Jun;102:26-38.
    PMID: 30954806 DOI: 10.1016/j.archoralbio.2019.03.024
    OBJECTIVE: Dental-derived stem cells originate from the embryonic neural crest, and exhibit high neurogenic potential. This study aimed to investigate whether a cocktail of eight small molecules (Valproic acid, CHIR99021, Repsox, Forskolin, SP600125, GO6983, Y-27632 and Dorsomorphin) can enhance the in vitro neurogenic differentiation of dental pulp stem cells (DPSCs), stem cells from apical papilla (SCAPs) and gingival mesenchymal stem cells (GMSCs), as a preliminary step towards clinical applications.

    MATERIALS AND METHODS: Neural induction was carried out with a small molecule cocktail based two-step culture protocol, over a total duration of 14 days. At the 8 and 14 day timepoints, the cells were analyzed for expression of neural markers with immunocytochemistry, qRT-PCR and Western Blot. The Fluo 4-AM calcium flux assay was also performed after a further 14 days of neural maturation.

    RESULTS: More pronounced morphological changes characteristic of the neural lineage (i.e. neuritogenesis) were observed in all three cell types treated with small molecules, as compared to the untreated controls. This was corroborated by the immunocytochemistry, qRT-PCR and western blot data, which showed upregulated expression of several early and mature neural markers in all three cell types treated with small molecules, versus the corresponding untreated controls. Finally, the Fluo-4 AM calcium flux assay showed consistently higher calcium transient (F/Fo) peaks for the small molecule-treated versus untreated control groups.

    CONCLUSIONS: Small molecules can enhance the neurogenic differentiation of DPSCs, SCAPs and GMSCs, which offer much potential for therapeutic applications.

    Matched MeSH terms: Stem Cells; Adult Stem Cells*
  8. Gao L, Thilakavathy K, Nordin N
    Cell Biol Int, 2013 Sep;37(9):875-87.
    PMID: 23619972 DOI: 10.1002/cbin.10120
    At the early stages of mammalian development, a number of developmentally plastic cells appear that possess the ability to give rise to all of the differentiated cell types normally derived from the three primary germ layers - unique character known as pluripotency. To date, embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) have been shown to be truly pluripotent. However, recent studies have revealed a variety of other cells that demonstrate pluripotentiality, including very small embryonic-like stem cells (VSELs), amniotic fluid stem cells (AFSCs), marrow-isolated adult multilineage inducible cells (MIAMI) and multipotent adult precursor cells (MAPCs). This review summarises key features of these six kinds of pluripotent and potentially pluripotent stem cells (ESCs, iPSCs, VSELs, AFSCs, MIAMI and MAPCs) and the evidence for their pluripotency properties.
    Matched MeSH terms: Multipotent Stem Cells/cytology*; Multipotent Stem Cells/metabolism; Embryonic Stem Cells/cytology*; Embryonic Stem Cells/metabolism; Adult Stem Cells/cytology*; Adult Stem Cells/metabolism; Induced Pluripotent Stem Cells/cytology*; Induced Pluripotent Stem Cells/metabolism
  9. Higuchi A, Hirad AH, Kumar SS, Munusamy MA, Alarfaj AA
    Acta Biomater, 2020 10 15;116:162-173.
    PMID: 32911107 DOI: 10.1016/j.actbio.2020.09.010
    Thermoresponsive surfaces enable the detachment of cells or cell sheets by decreasing the temperature of the surface when harvesting the cells. However, human pluripotent stem cells (hPSCs), such as embryonic stem cells and induced pluripotent stem cells, cannot be directly cultured on a thermoresponsive surface; hPSCs need a specific extracellular matrix to bind to the integrin receptors on their surfaces. We prepared a thermoresponsive surface by using poly(N-isopropylacrylamide-co-butylacrylate) and recombinant vitronectin to provide an optimal coating concentration for the hPSC culture. hPSCs can be cultured on the same thermoresponsive surface for 5 passages by partial detachment of the cells from the surface by decreasing the temperature for 30 min; then, the remaining hPSCs were subsequently cultured on the same dishes following the addition of new cultivation media. The detached cells, even after continual culture for five passages, showed high pluripotency, the ability to differentiate into cells derived from the 3 germ layers and the ability to undergo cardiac differentiation.
    Matched MeSH terms: Pluripotent Stem Cells*; Embryonic Stem Cells
  10. Jeganathan VS, Palanisamy M
    Curr Opin Ophthalmol, 2010 May;21(3):213-7.
    PMID: 20393292 DOI: 10.1097/ICU.0b013e32833867ad
    Adult ocular stem cells have the potential to restore vision in patients previously deemed incurable. This review summarizes strides in stem cell research and stumbling blocks that must be overcome to enable treatment viability in ophthalmology.
    Matched MeSH terms: Embryonic Stem Cells*; Adult Stem Cells*
  11. Higuchi A, Ling QD, Kumar SS, Munusamy MA, Alarfaj AA, Chang Y, et al.
    Lab Invest, 2015 Jan;95(1):26-42.
    PMID: 25365202 DOI: 10.1038/labinvest.2014.132
    Induced pluripotent stem cells (iPSCs) provide a platform to obtain patient-specific cells for use as a cell source in regenerative medicine. Although iPSCs do not have the ethical concerns of embryonic stem cells, iPSCs have not been widely used in clinical applications, as they are generated by gene transduction. Recently, iPSCs have been generated without the use of genetic material. For example, protein-induced PSCs and chemically induced PSCs have been generated by the use of small and large (protein) molecules. Several epigenetic characteristics are important for cell differentiation; therefore, several small-molecule inhibitors of epigenetic-modifying enzymes, such as DNA methyltransferases, histone deacetylases, histone methyltransferases, and histone demethylases, are potential candidates for the reprogramming of somatic cells into iPSCs. In this review, we discuss what types of small chemical or large (protein) molecules could be used to replace the viral transduction of genes and/or genetic reprogramming to obtain human iPSCs.
    Matched MeSH terms: Pluripotent Stem Cells/cytology*
  12. Ibtisham F, Awang-Junaidi AH, Honaramooz A
    Cell Tissue Res, 2020 May;380(2):393-414.
    PMID: 32337615 DOI: 10.1007/s00441-020-03212-x
    Spermatogonial stem cells (SSCs) are a rare group of cells in the testis that undergo self-renewal and complex sequences of differentiation to initiate and sustain spermatogenesis, to ensure the continuity of sperm production throughout adulthood. The difficulty of unequivocal identification of SSCs and complexity of replicating their differentiation properties in vitro have prompted the introduction of novel in vivo models such as germ cell transplantation (GCT), testis tissue xenografting (TTX), and testis cell aggregate implantation (TCAI). Owing to these unique animal models, our ability to study and manipulate SSCs has dramatically increased, which complements the availability of other advanced assisted reproductive technologies and various genome editing tools. These animal models can advance our knowledge of SSCs, testis tissue morphogenesis and development, germ-somatic cell interactions, and mechanisms that control spermatogenesis. Equally important, these animal models can have a wide range of experimental and potential clinical applications in fertility preservation of prepubertal cancer patients, and genetic conservation of endangered species. Moreover, these models allow experimentations that are otherwise difficult or impossible to be performed directly in the target species. Examples include proof-of-principle manipulation of germ cells for correction of genetic disorders or investigation of potential toxicants or new drugs on human testis formation or function. The primary focus of this review is to highlight the importance, methodology, current and potential future applications, as well as limitations of using these novel animal models in the study and manipulation of male germline stem cells.
    Matched MeSH terms: Adult Germline Stem Cells/physiology*
  13. Abdul Wahab AY, Md Isa ML, Ramli R
    Malays J Med Sci, 2016 May;23(3):40-8.
    PMID: 27418868
    Spermatogonial stem cells (SSCs) are classifiedas a unique adult stem cells that have capability to propagate, differentiate, and transmit genetic information to the next generation. Studies on human SSCs may help resolve male infertility problems, especially in azoospermia patients. Therefore, this study aims to propagate SSCs in-vitro with a presence of growth factor and detect SSC-specific protein cell surface markers.
    Matched MeSH terms: Adult Stem Cells; Adult Germline Stem Cells
  14. Alqarni AJ, Rambely AS, Alharbi SA, Hashim I
    Math Biosci Eng, 2021 07 19;18(5):6288-6304.
    PMID: 34517534 DOI: 10.3934/mbe.2021314
    Stem cells play a critical role in regulatory operations, overseeing tissue regeneration and tissue homeostasis. In this paper, a mathematical model is proposed and analyzed to study the impact of stem cell transplantation on the dynamical behavior of stroke therapy, which is assumed to be based on transplanting dead brain cells following a stroke. We transform the method of using hierarchical cell systems into a method of using different compartment variables by using ordinary differential equations, each of which elucidates a well-defined differentiation stage along with the effect of mature cells in improving the brain function after a stroke. Stem cells, progenitor cells, and the impacts of the stem cells transplanted on brain cells are among the variables considered. The model is studied analytically and solved numerically using the fourth-order Runge-Kutta method. We analyze the structure of equilibria, the ability of neural stem cells to proliferate and differentiate, and the stability properties of equilibria for stem cell transplantation. The model is considered to be stable after transplantation if the stem cells and progenitor cells differentiate into mature nerve cells in the brain. The results of the model analysis and simulation facilitate the identification of various biologically probable parameter sets that can explain the optimal time for stem cell replacement of damaged brain cells. Associating the classified parameter sets with recent experimental and clinical findings contributes to a better understanding of therapeutic mechanisms that promote the reconstitution of brain cells after an ischemic stroke.
    Matched MeSH terms: Neural Stem Cells*
  15. Chen YM, Chen LH, Li MP, Li HF, Higuchi A, Kumar SS, et al.
    Sci Rep, 2017 03 23;7:45146.
    PMID: 28332572 DOI: 10.1038/srep45146
    Establishing cultures of human embryonic (ES) and induced pluripotent (iPS) stem cells in xeno-free conditions is essential for producing clinical-grade cells. Development of cell culture biomaterials for human ES and iPS cells is critical for this purpose. We designed several structures of oligopeptide-grafted poly (vinyl alcohol-co-itaconic acid) hydrogels with optimal elasticity, and prepared them in formations of single chain, single chain with joint segment, dual chain with joint segment, and branched-type chain. Oligopeptide sequences were selected from integrin- and glycosaminoglycan-binding domains of the extracellular matrix. The hydrogels grafted with vitronectin-derived oligopeptides having a joint segment or a dual chain, which has a storage modulus of 25 kPa, supported the long-term culture of human ES and iPS cells for over 10 passages. The dual chain and/or joint segment with cell adhesion molecules on the hydrogels facilitated the proliferation and pluripotency of human ES and iPS cells.
    Matched MeSH terms: Pluripotent Stem Cells/cytology*; Pluripotent Stem Cells/metabolism*; Embryonic Stem Cells/cytology; Embryonic Stem Cells/metabolism
  16. Sung TC, Li HF, Higuchi A, Ling QD, Yang JS, Tseng YC, et al.
    J Vis Exp, 2018 02 03.
    PMID: 29443075 DOI: 10.3791/57314
    The effect of physical cues, such as the stiffness of biomaterials on the proliferation and differentiation of stem cells, has been investigated by several researchers. However, most of these investigators have used polyacrylamide hydrogels for stem cell culture in their studies. Therefore, their results are controversial because those results might originate from the specific characteristics of the polyacrylamide and not from the physical cue (stiffness) of the biomaterials. Here, we describe a protocol for preparing hydrogels, which are not based on polyacrylamide, where various stem, cells including human embryonic stem (ES) cells and human induced pluripotent stem (iPS) cells, can be cultured. Hydrogels with varying stiffness were prepared from bioinert polyvinyl alcohol-co-itaconic acid (P-IA), with stiffness controlled by crosslinking degree by changing crosslinking time. The P-IA hydrogels grafted with and without oligopeptides derived from extracellular matrix were investigated as a future platform for stem cell culture and differentiation. The culture and passage of amniotic fluid stem cells, adipose-derived stem cells, human ES cells, and human iPS cells is described in detail here. The oligopeptide P-IA hydrogels showed superior performances, which were induced by their stiffness properties. This protocol reports the synthesis of the biomaterial, their surface manipulation, along with controlling the stiffness properties and finally, their impact on stem cell fate using xeno-free culture conditions. Based on recent studies, such modified substrates can act as future platforms to support and direct the fate of various stem cells line to different linkages; and further, regenerate and restore the functions of the lost organ or tissue.
    Matched MeSH terms: Pluripotent Stem Cells/cytology; Pluripotent Stem Cells/metabolism*; Induced Pluripotent Stem Cells/cytology
  17. Ho SY, Goh CW, Gan JY, Lee YS, Lam MK, Hong N, et al.
    Zebrafish, 2014 Oct;11(5):407-20.
    PMID: 24967707 DOI: 10.1089/zeb.2013.0879
    Existing zebrafish embryonic stem (ES) cell lines are derived and maintained using feeder layers. We describe here the derivation and long-term culture of an ES cell-like line derived from zebrafish blastomeres without the use of feeder cells. This line, designated as ZES1, has been maintained for more than 800 days in defined Dulbecco's modified Eagle's medium supplemented with fetal bovine serum, zebrafish embryo extract, trout serum, and human basic fibroblast growth factor. ZES1 cells possessed a morphology typical of ES cells, being round or polygonal in shape with a large nucleus and sparse cytoplasm and were mostly diploid. The cells formed individual colonies consisting of tightly packed cells that stained positively for alkaline phosphatase. ZES1 cells also formed embryoid bodies when transferred onto uncoated wells. The pluripotent nature of ZES1 cells was confirmed when they could be induced to differentiate in vitro into several cell types, through low- or high-density culture conditions. Treatment with retinoic acid also induced the differentiation of ZES1 cells into primarily neuronal cells. Using immunostaining and real-time polymerase chain reaction, we showed that Sox2, a known pluripotent marker in mammalian ES cells, was also present in ZES1 cells. Chimera experiments revealed that fluorescent-labeled ZES1 cells microinjected into zebrafish blastulas participated in the formation of all three germ layers. Using GFP-labeled ZES1 cells, chimera germline transmission was also demonstrated at the F1 generation. In conclusion, ZES1 cells possess both in vitro and in vivo pluripotency characteristics, indicating that nonmammalian ES cells can be readily derived and maintained for a long term under feeder-free culture conditions.
    Matched MeSH terms: Embryonic Stem Cells/cytology; Embryonic Stem Cells/metabolism*
  18. Das AK, Gopurappilly R, Parhar I
    Curr Stem Cell Res Ther, 2011 Jun;6(2):93-104.
    PMID: 21190537
    Spinal cord injuries (SCIs) are a common form of trauma that leaves a huge trail of morbidity and human suffering in its wake. They occur mostly among the young, causing severe physical, psychological, social and economic burdens. The treatment of this condition has rather been disappointing; most of the management strategies being mainly supportive and prophylactic. In recent years there has been an emerging interest in the use of stem cells to regenerate the nervous tissue that has been damaged or lost. Although there has been much hype and unfounded hope, modest successes have been witnessed, and it is possible that these therapeutic strategies may have much more to offer in the future. This paper will review the current strategies of exploring cell-based therapies, mainly different types of stem cells to treat SCI along with the evidence that has been accumulated over the past decade in a rational bench-to-bedside approach. Furthermore, critical aspects such as the mode of delivery and ethical considerations are also discussed along with feasible suggestions for future translational research to provide a contextual picture of the current state of advancements in this field. The impediments to regeneration in the site of injury are briefly explained along with the benefits and drawbacks of different cell types used in the treatment of this condition. We hope that this review will offer a significant insight into this challenging clinical condition.
    Matched MeSH terms: Stem Cells/cytology*; Stem Cells/physiology*
  19. Khoo TS, Jamal R, Abdul Ghani NA, Alauddin H, Hussin NH, Abdul Murad NA
    Stem Cell Rev Rep, 2020 04;16(2):251-261.
    PMID: 32016780 DOI: 10.1007/s12015-020-09956-x
    The discovery of induced pluripotent stem (iPS) cells in 2006 marked a major breakthrough in regenerative medicine, enabling reversal of terminally differentiated somatic cells into pluripotent stem cells. The embryonic stem (ES) cells-like pluripotency and unlimited self-renewal capability of iPS cells have granted them enormous potential in many applications, particularly regenerative therapy. Unlike ES cells, however, iPS cells exhibit somatic memories which were carried over from the tissue of origin thus limited its translation in clinical applications. This review provides an updated overview of the retention of various somatic memories associated with the cellular identity, age and metabolism of tissue of origin in iPS cells. The influence of cell types, stage of maturation, age and various other factors on the retention of somatic memory has been discussed. Recent evidence of somatic memory in the form of epigenetic, transcriptomic, metabolic signatures and its functional manifestations in both in vitro and in vivo settings also have been reviewed. The increasing number of studies which had adopted isogenic cell lines for comparisons in recent years had facilitated the identification of genuine somatic memories. These memories functionally affect iPS cells and its derivatives and are potentially tumorigenic thus, raising concerns on their safety in clinical application. Various approaches for memory erasure had since being reported and their efficacies were highlighted in this review.
    Matched MeSH terms: Induced Pluripotent Stem Cells/cytology*; Induced Pluripotent Stem Cells/metabolism*
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