Human sperm created from embryonic stem cellsJuly 08, 2009Human sperm have been created using embryonic stem cells for the first time in a scientific development which will lead researchers to a better understanding of the causes of infertility. Researchers led by Professor Karim Nayernia at Newcastle University and the NorthEast England Stem Cell Institute (NESCI) have developed a new technique which has made the creation of human sperm possible in the laboratory. The work is published today (8th July 2009) in the academic journal Stem Cells and Development. The NorthEast England Stem Cell Institute (NESCI) is a collaboration between Newcastle and Durham Universities, Newcastle NHS Foundation Trust and other partners. Professor Nayernia says: "This is an important development as it will allow researchers to study in detail how sperm forms and lead to a better understanding of infertility in men - why it happens and what is causing it. This understanding could help us develop new ways to help couples suffering infertility so they can have a child which is genetically their own." "It will also allow scientists to study how cells involved in reproduction are affected by toxins, for example, why young boys with leukaemia who undergo chemotherapy can become infertile for life - and possibly lead us to a solution." The team also believe that studying the process of forming sperm could lead to a better understanding of how genetic diseases are passed on. In the technique developed at Newcastle, stem cells with XY chromosomes (male) were developed into germline stem cells which were then prompted to complete meiosis - cell division with halving of the chromosome set. These were shown to produce fully mature, sperm called scientifically, In Vitro Derived sperm (IVD sperm). In contrast, stem cells with XX chromosomes (female) were prompted to form early stage sperm, spermatagonia, but did not progress further. This demonstrates to researchers that the genes on a Y chromosome are essential for meiosis and for sperm maturation. IVD sperm The IVD sperm will not and cannot be used for fertility treatment. As well as being prohibited by UK law, the research team say fertilization of human eggs and implantation of embryos would hold no scientific merit for them as they want to study the process as a model for research. "While we can understand that some people may have concerns, this does not mean that humans can be produced 'in a dish' and we have no intention of doing this. This work is a way of investigating why some people are infertile and the reasons behind it. If we have a better understanding of what's going on it could lead to new ways of treating infertility," adds Professor Nayernia. Technique The Newcastle University team have developed a method for establishing early stage sperm from human embryonic stem cells in the laboratory. The embryonic stem cells were cultured in a new medium containing vitamin A derivative (retinoic acid), in a new technique established by the team. Based on this technique, the cells differentiated into germline stem cells. These expressed a protein which was stained with a green fluorescent marker and they were separated out by FACSTM (Fluorescence-activated cell sorting) using a laser. After further differentiation, these in vitro derived germline stem cells expressed markers which are specific to primordial germ cells, spermatogonial stem cells, meiotic (spermatocytes) and post meiotic germ cells (spermatids and sperm). These results indicated maturation of the primordial germ cells to haploid male gametes - called IVD sperm - characterised by containing half a chromosome set (23 chromosomes). Newcastle University |
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| Related Embryonic Stem Cells Current Events and Embryonic Stem Cells News Articles First reconstitution of an epidermis from human embryonic stem cells Stem cell research is making great strides. This is yet again illustrated by a study carried out by the I-STEM* Institute (I-STEM/ Inserm UEVE U861/AFM), published in the Lancet on 21 November 2009. The I-STEM team, directed by Marc Peschanski has just succeeded in recreating a whole epidermis from human embryonic stem cells. UCI embryonic stem cell therapy restores walking ability in rats with neck injuries The first human embryonic stem cell treatment approved by the FDA for human testing has been shown to restore limb function in rats with neck spinal cord injuries - a finding that could expand the clinical trial to include people with cervical damage. Of mice and men: Stem cells and ethical uncertainties The recent creation of live mice from induced pluripotent stem cells (iPSCs) not only represents a remarkable scientific achievement, but also raises important issues, according to bioethicists at The Johns Hopkins University's Berman Institute of Bioethics. NIH-funded researchers transform embryonic stem cells into human germ cells Researchers funded in part by the National Institutes of Health have discovered how to transform human embryonic stem cells into germ cells, the embryonic cells that ultimately give rise to sperm and eggs. Placental precursor stem cells require testosterone-free environment to survive Trophoblast stem cells (TSCs), cells found in the layer of peripheral embryonic stem cells from which the placenta is formed, are thought to exhibit "immune privilege" that aids cell survivability and is potentially beneficial for cell and gene therapies. Endocrine Society calls for expanded scope and funding for stem cell research Stem cell research holds great promise for the treatment of millions of Americans with debilitating and possibly fatal diseases. Small mechanical forces have big impact on embryonic stem cells Applying a small mechanical force to embryonic stem cells could be a new way of coaxing them into a specific direction of differentiation, researchers at the University of Illinois report. Applications for force-directed cell differentiation include therapeutic cloning and regenerative medicine. Fate Therapeutics announces creation of small molecule platform for commercial-scale reprogramming Fate Therapeutics, Inc. announced today the generation of human induced-pluripotent stem cells (iPSCs) using a combination of small molecules that significantly improves the speed and efficiency of reprogramming. A major step in making better stem cells from adult tissue October 15, 2009 A team led by scientists from The Scripps Research Institute has developed a method that dramatically improves the efficiency of creating stem cells from human adult tissue, without the use of embryonic cells. New strategy for mending broken hearts? By mimicking the way embryonic stem cells develop into heart muscle in a lab, Duke University bioengineers believe they have taken an important first step toward growing a living "heart patch" to repair heart tissue damaged by disease. More Embryonic Stem Cells Current Events and Embryonic Stem Cells News Articles |
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