969 research outputs found

    Astrocytes in Pathogenesis of ALS Disease and Potential Translation into Clinic

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    Astrocytes are the major cell population in the central nervous system (CNS) and play pivotal role in CNS homeostasis and functionality. Malfunction of astrocytes were implicated in multiple neurodegenerative diseases and disorders, including amyotrophic lateral sclerosis (ALS), spinal cord injury (SCI), brain stroke, Parkinson’s disease (PD), and Alzheimer disease (AD). These new insights led to the rationale that transplantation of healthy and functional human astrocytes could support survival of neurons and be of therapeutic value in treating neurodegenerative diseases. Here, we will mainly focus on the role of astrocytes in ALS disease, the major cell sources for generation of human astrocytes, or astrocyte like cells and show how multiple preclinical studies demonstrate the efficacy of these cells in animal models. In addition, we will cover immerging early stage clinical trials that are currently being conducted using human astrocytes or human astrocyte like cell population

    Establishment of human embryonic stem cell-transfected clones carrying a marker for undifferentiated cells

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    AbstractHuman embryonic stem (ES) cells are pluripotent cell lines that have been derived from the inner cell mass (ICM) of blastocyst stage embryos [1–3]. They are characterized by their ability to be propagated indefinitely in culture as undifferentiated cells with a normal karyotype and can be induced to differentiate in vitro into various cell types [1, 2, 4–6]. Thus, human ES cells promise to serve as an unlimited cell source for transplantation. However, these unique cell lines tend to spontaneously differentiate in culture and therefore are difficult to maintain. Furthermore, colonies may contain several cell types and may be composed of cells other than pluripotent cells [1, 2, 6]. In order to overcome these difficulties and establish lines of cells with an undifferentiated phenotype, we have introduced a reporter gene that is regulated by a promoter of an ES cell-enriched gene into the cells. For the introduction of DNA into human ES cells, we have established a specific transfection protocol that is different from the one used for murine ES cells. Human ES cells were transfected with enhanced green fluorescence protein (EGFP), under the control of murine Rex1 promoter. The transfected cells show high levels of GFP expression when in an undifferentiated state. As the cells differentiate, this expression is dramatically reduced in monolayer cultures as well as in the primitive endoderm of early stage (simple) embryoid bodies (EBs) and in mature EBs. The undifferentiated cells expressing GFP can be analyzed and sorted by using a Fluorescence Activated Cell Sorter (FACS). Thus, we have established lines of human ES cells in which only undifferentiated cells are fluorescent, and these cells can be followed and selected for in culture. We also propose that the pluripotent nature of the culture is made evident by the ability of the homogeneous cell population to form EBs. The ability to efficiently transfect human ES cells will provide the means to study and manipulate these cells for the purpose of basic and applied research

    Is Mesh Becoming More Popular? Dilemmas in Urogynecology: A National Survey

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    The use of vaginal mesh in pelvic organ prolapse (POP) repair surgery has become more common in recent years. The purpose of the current study was to evaluate the common practice of Israeli urogynecologists, and to determine whether surgical practice has changed over the last two years. Methods. In 2009 and again in 2011, a survey was mailed to all urogynecologists affiliated with an academic institute in Israel. The survey consisted of 7 Likert-scale items and 3 open questions; the latter inquired about preferred type of surgery in three clinical scenarios. Results. Of 22 practitioners, 15 responded to the survey. The number of urogynecologists who reported using vaginal mesh for the repair of primary POP increased from 47 to 67% from 2009 to 2011. The number who would not use vaginal mesh in POP repair of elderly patients dropped from 60 to 3%. Finally, for the treatment of a 35-year-old patient with stage III uterine prolapse who desired to preserve fertility, 13% recommended the used vaginal mesh in 2009 compared with 47% in 2011. Conclusion. A survey of practitioners shows that the use of vaginal mesh for the repair of primary and recurrent pelvic organ prolapse has become more common among Israeli urogynecologists

    Endocrine profiles after triggering of final oocyte maturation with GnRH agonist after cotreatment with the GnRH antagonist ganirelix during ovarian hyperstimulation for in vitro fertilization

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    In a randomized multicenter study, the efficacies of two different GnRH agonists were compared with that of hCG for triggering final stages of oocyte maturation after ovarian hyperstimulation for in vitro fertilization. Ovarian stimulation was conducted by recombinant FSH (Puregon), and the GnRH antagonist ganirelix (Orgalutran) was coadministered for the prevention of a premature LH rise. Luteal support was provided by daily progestin administration. Frequent blood sampling was performed at midcycle in the first 47 eligible subjects included in the current study, who were randomized for a single dose of 0.2 mg triptorelin (n = 17), 0.5 mg leuprorelin (n = 15), or 10,000 IU hCG (n = 15). Serum concentrations of LH, FSH, E2, and progesterone (P) were assessed at variable intervals. LH peaked at 4 h after both triptorelin and leuprorelin administration, with median LH levels of 130 and 107 IU/liter (P < 0.001), respectively. LH levels returned to baseline after 24 h. Subjects receiving hCG showed peak levels of 240 IU/liter hCG 24 h after administration. A rise in FSH to 19 IU/liter (P < 0.001) was noted in both GnRH agonist groups 8 h after injection. Within 24 h the areas under the curve for LH and FSH were significantly higher (P < 0.001) in both GnRH agonist groups compared with that for hCG. E2 and P levels were similar for all groups up to the day of oocyte retrieval. Luteal phase areas under the curve for P and E2 were significantly elevated (P < 0.001) in the hCG group. The mean (+/-SD) numbers of oocytes retrieved were 9.8 +/- 5.4, 8.7 +/- 4.5, and 8.3 +/- 3.3; the percentages of metaphase II oocytes were 72%, 85%, and 86%; and fertilization rates were 61%, 62%, and 56% in the triptorelin, leuprorelin, and hCG group, respectively (P = NS for all three comparisons). These findings support the effective induction of final oocyte maturation in both GnRH agonist groups. In summary, after treatment with the GnRH antagonist ganirelix for the prevention of premature LH surges, triggering of final stages of oocyte maturation can be induced effectively by a single bolus injection of GnRH agonist, as demonstrated by the induced endogenous LH and FSH surge and the quality and fertilization rate of recovered oocytes. Moreover, corpus luteum formation is induced by GnRH agonists with luteal phase steroid levels closer to the physiological range compared with hCG. This more physiological approach for inducing oocyte maturation may represent a successful and safer alternative for in vitro fertilization patients undergoing ovarian hyperstimulation

    Extracellular Matrix Aggregates from Differentiating Embryoid Bodies as a Scaffold to Support ESC Proliferation and Differentiation

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    Embryonic stem cells (ESCs) have emerged as potential cell sources for tissue engineering and regeneration owing to its virtually unlimited replicative capacity and the potential to differentiate into a variety of cell types. Current differentiation strategies primarily involve various growth factor/inducer/repressor concoctions with less emphasis on the substrate. Developing biomaterials to promote stem cell proliferation and differentiation could aid in the realization of this goal. Extracellular matrix (ECM) components are important physiological regulators, and can provide cues to direct ESC expansion and differentiation. ECM undergoes constant remodeling with surrounding cells to accommodate specific developmental event. In this study, using ESC derived aggregates called embryoid bodies (EB) as a model, we characterized the biological nature of ECM in EB after exposure to different treatments: spontaneously differentiated and retinoic acid treated (denoted as SPT and RA, respectively). Next, we extracted this treatment-specific ECM by detergent decellularization methods (Triton X-100, DOC and SDS are compared). The resulting EB ECM scaffolds were seeded with undifferentiated ESCs using a novel cell seeding strategy, and the behavior of ESCs was studied. Our results showed that the optimized protocol efficiently removes cells while retaining crucial ECM and biochemical components. Decellularized ECM from SPT EB gave rise to a more favorable microenvironment for promoting ESC attachment, proliferation, and early differentiation, compared to native EB and decellularized ECM from RA EB. These findings suggest that various treatment conditions allow the formulation of unique ESC-ECM derived scaffolds to enhance ESC bioactivities, including proliferation and differentiation for tissue regeneration applications. © 2013 Goh et al

    Human embryonic stem cells from aneuploid blastocysts identified by pre-implantation genetic screening

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    Human embryonic stem cells are derived from the inner cell mass of pre-implantation embryos. The cells have unlimited proliferation potential and capacity to differentiate into the cells of the three germ layers. Human embryonic stem cells are used to study human embryogenesis and disease modeling and may in the future serve as cells for cell therapy and drug screening. Human embryonic stem cells are usually isolated from surplus normal frozen embryos and were suggested to be isolated from diseased embryos detected by pre-implantation genetic diagnosis. Here we report the isolation of 12 human embryonic stem cell lines and their thorough characterization. The lines were derived from embryos detected to have aneuploidy by pre-implantation genetic screening. Karyotype analysis of these cell lines showed that they are euploid, having 46 chromosomes. Our interpretation is that the euploid cells originated from mosaic embryos, and in vitro selection favored the euploid cells. The undifferentiated cells exhibited long-term proliferation and expressed markers typical for embryonic stem cells such as OCT4, NANOG, and TRA-1-60. The cells manifested pluripotent differentiation both in vivo and in vitro. To further characterize the different lines, we have analyzed their ethnic origin and the family relatedness among them. The above results led us to conclude that the aneuploid mosaic embryos that are destined to be discarded can serve as source for normal euploid human embryonic stem cell lines. These lines represent various ethnic groups; more lines are needed to represent all populations

    Physical Passaging of Embryoid Bodies Generated from Human Pluripotent Stem Cells

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    Spherical three-dimensional cell aggregates called embryoid bodies (EBs), have been widely used in in vitro differentiation protocols for human pluripotent stem cells including human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs). Recent studies highlight the new devices and techniques for hEB formation and expansion, but are not involved in the passaging or subculture process. Here, we provide evidence that a simple periodic passaging markedly improved hEB culture condition and thus allowed the size-controlled, mass production of human embryoid bodies (hEBs) derived from both hESCs and hiPSCs. hEBs maintained in prolonged suspension culture without passaging (>2 weeks) showed a progressive decrease in the cell growth and proliferation and increase in the apoptosis compared to 7-day-old hEBs. However, when serially passaged in suspension, hEB cell populations were significantly increased in number while maintaining the normal rates of cell proliferation and apoptosis and the differentiation potential. Uniform-sized hEBs produced by manual passaging using a 1∶4 split ratio have been successfully maintained for over 20 continuous passages. The passaging culture method of hEBs, which is simple, readily expandable, and reproducible, could be a powerful tool for improving a robust and scalable in vitro differentiation system of human pluripotent stem cells
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