If someone could only figure out how to get those pesky embryos to actually stick once they are put in place! If the embryos "look good" enough to transplant and they "should" implant, well then WHY don't they? I am posting here the link to this entire article however I didn't want you to miss the simple explanation:
"Implantation relies on a set of closely coordinated events occurring between a very early stage embryo and the lining of the womb. The embryo must initially attach to and form a contact with the lining. Then cells from the embryo begin to invade the womb lining, eventually connecting with the mother's blood vessels and forming the placenta.
'The embryo and womb lining talk to each other, molecularly speaking, which allows them to interact,' explains Professor Mardon. 'When the embryo lands on the surface of the uterus wall, it triggers a cascade of signals in both the embryo and uterus. The resulting changes allow the embryo to invade the lining.'
'This invasion process has to be tightly regulated for a placenta to form correctly and hook up with the maternal blood supply,' Professor Helen J. Mardon adds.
So what I am reading here is that the embryos can be deemed "perfect" but if the uterine lining isn't up to having a "conversation" with the embryo then all bets are off. I don't believe that this is new news...just put out there in more simplistic terms....
Sharon LaMothe
www.InfertilityAnswers.net
Understanding Embryo Implantation Offers Insight Into Infertility
Article Date: 28 Sep 2008
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A process that governs embryo implantation in the womb in humans has been identified for the first time. The Oxford University research, published in the journal PNAS, could shed light on what goes wrong when embryos fail to implant in the lining of the womb, a leading cause of infertility.
'In many women, attachment and implantation doesn't happen and this is a major cause of infertility,' says Professor Helen J. Mardon of the Nuffield Department of Obstetrics and Gynaecology and St Catherine's College, University of Oxford, who led the study. 'By understanding how this process works, we may be able to inform the development of drugs to help embryos implant properly.'
Implantation relies on a set of closely coordinated events occurring between a very early stage embryo and the lining of the womb. The embryo must initially attach to and form a contact with the lining. Then cells from the embryo begin to invade the womb lining, eventually connecting with the mother's blood vessels and forming the placenta.
'The embryo and womb lining talk to each other, molecularly speaking, which allows them to interact,' explains Professor Mardon. 'When the embryo lands on the surface of the uterus wall, it triggers a cascade of signals in both the embryo and uterus. The resulting changes allow the embryo to invade the lining.'
'This invasion process has to be tightly regulated for a placenta to form correctly and hook up with the maternal blood supply,' she adds.
The Oxford team, along with Professor Anne J. Ridley at King's College, London, have now identified molecules that are responsible for controlling the invasion of human embryo cells into the womb lining. Their research, funded by the Wellcome Trust and Medical Research Council, showed two proteins belonging to a family called Rho GTPases are involved. These proteins ensure cells in a small area of the womb lining move out of the way to allow cells from the embryo to invade.
'We have shown that two proteins, called Rac1 and RhoA, control the invasion,' says Professor Mardon. 'The first stimulates cells in the womb lining to move and allow the embryo to invade and implant properly while the second inhibits this. We believe this controlled balance of the two proteins is critical for successful implantation of the embryo.'
'If the balance of the Rho GTPases is altered, the cells of the womb lining don't migrate and the embryo doesn't implant.'
The researchers had to develop a way to investigate the molecular process of human implantation in the lab. Embryos were added to a layer of cells from the womb lining in a culture dish. The research team were then able to video embryos implant themselves in the cell layer.
'Essentially what we've done is to capture a particular stage of implantation going on in a petri dish,' says Professor Mardon. 'The experiment mimics the stage in which an early-stage human embryo invades the lining of the womb, and allows us to dissect the molecular processes that control this critical stage of implantation.'
'Implantation of the human embryo requires Rac1-dependent endometrial stromal cell migration' by Seema Grewal, Janet G. Carver, Anne J. Ridley and Helen J. Mardon is to be published in PNAS. It is embargoed until 22:00 BST / 17:00 EDT on Monday 29 September 2008.
Endometrial tissue samples were obtained with informed consent in accordance with the requirements of the Central Oxford Research Ethics Committee. Embryos were donated for research with informed consent by patients attending the Oxford Fertility Unit at the John Radcliffe Hospital, Oxford. Experiments were performed with ethical approval from the Oxfordshire Research Ethics Committee, and a research license was granted by the Human Fertilization and Embryology Authority.
Oxford University's Medical Sciences Division is one of the largest biomedical research centres in Europe. It represents almost one-third of Oxford University's income and expenditure, and two-thirds of its external research income. Oxford's world-renowned global health programme is a leader in the fight against infectious diseases (such as malaria, HIV/AIDS, tuberculosis and avian flu) and other prevalent diseases (such as cancer, stroke, heart disease and diabetes). Key to its success is a long-standing network of dedicated Wellcome Trust-funded research units in Asia (Thailand, Laos and Vietnam) and Kenya, and work at the MRC Unit in The Gambia. Long-term studies of patients around the world are supported by basic science at Oxford and have led to many exciting developments, including potential vaccines for tuberculosis, malaria and HIV, which are in clinical trials.
http://www.medsci.ox.ac.uk
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