Human embryonic stem cells have the potential to develop into eggs and sperm in the laboratoryJune 20, 2005Copenhagen, Denmark: Scientists in the UK have proved that human embryonic stem cells can develop in the laboratory into the early forms of cells that eventually become eggs or sperm. Their work opens up the possibility that eggs and sperm could be grown from stem cells and used for assisted reproduction, therapeutic cloning and the creation of more stem cells for further research and for the improved treatments for patients suffering from a range of diseases. Behrouz Aflatoonian will tell the 21st annual conference of the European Society of Human Reproduction and Embryology today (Monday 20 June) that the research also solves the practical and ethical problems associated with obtaining human samples of primordial germ cells (PGCs), which are the ancestral cells that eventually form eggs and sperm (gametes). "Investigating the mechanisms of human primordial germ cell and gamete development is important for understanding the causes of infertility and the potential harmful effects of environmental chemicals on reproductive development," he will say. "But at present it is very difficult to obtain human samples of these cells as they only occur early in development." Mr Aflatoonian, who is a PhD student in Professor Harry Moore's laboratory at the Centre for Stem Cell Biology, University of Sheffield, UK, said that studies with mice embryonic stem cells had shown that they were capable of differentiating into PGCs and subsequently eggs and sperm, so he set out to see if the same applied to human embryonic stem cells (HESCs). "We derived six embryonic stem cell lines from embryos donated for research under HFEA regulations by couples undergoing IVF treatment. In addition, we utilised cell lines from the University of Wisconsin. "The human embryonic stem cells were allowed to develop into collections of cells called embryoid bodies. The embryoid bodies were tested to see which genes were active, or 'expressed', in them and it was found that within two weeks a very tiny proportion of cells in the embryoid bodies began to express some of the genes that are found in human primordial germ cells. Some cells also expressed proteins only found in maturing sperm. This suggests that HESCs may have the ability to develop into PGCs and early gametes as has been shown previously for mouse embryonic stem cells." However, Mr Aflatoonian stressed that there was still a lot of work to be done before the promise of these early results could be translated into reality. "Embryoid bodies can differentiate into all sorts of tissue types, so we need to choose the cells that are going to develop into PGCs and then work out how we can encourage them to grow into gametes. "Producing functional gametes is much more difficult, because we have to recreate for the cultured cells the environment of the developing follicle for egg development or the tissue of the testis for sperm. We want to test whether HESCs can differentiate to cells that produce the hormones for sperm and egg development and isolate these as well. What is extraordinary is that the embryoid bodies seem to produce spontaneously the tissue and environment conducive for sperm and egg development in quite a short time in culture." Speaking before the conference, Prof Moore said: "One of the reasons for doing this research is that it may allow us to investigate the very earliest processes of how a human gamete and gonad (ovary and testis) develops. Many scientists believe that environmental chemical pollutants that mimic the action of hormones (so called endocrine disrupting chemicals) might interfere with human development at this stage and cause congenital abnormalities, infertility and possibly cancer (in particular testicular cancer). By developing suitable tests with embryonic stem cells as they differentiate to germ cells we can investigate the action of these chemicals in the laboratory. "Ultimately it might be possible to produce sperm and eggs for use in assisted conception treatments. This is a long way off and we would have to prove it was safe because, for example, the culture process may cause genetic changes. For some men and women this would be the only route for producing sperm and eggs. It would not be reproductive cloning as fertilisation would involve only one set of gametes produced in this way and therefore a unique embryo would form. "In addition, if we could produce eggs from HESCs they could also be used for therapeutic cloning (somatic nuclear replacement) circumventing the need for eggs from patients who donate them, as this is a major limitation of this technique at the moment. We would then have completed the circle of making HESCs from eggs that came from HESCs - what came first the chicken or the egg?!" European Society for Human Reproduction and Embryo |
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| Related Embryonic Stem Cells Current Events and Embryonic Stem Cells News Articles 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. Liver cells grown from patients' skin cells Scientists at The Medical College of Wisconsin in Milwaukee have successfully produced liver cells from patients' skin cells opening the possibility of treating a wide range of diseases that affect liver function. Major improvements made in engineering heart repair patches from stem cells University of Washington (UW) researchers have succeeded in engineering human tissue patches free of some problems that have stymied stem-cell repair for damaged hearts. More Embryonic Stem Cells Current Events and Embryonic Stem Cells News Articles |
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