Tag Archives: Stem Cells

Adult stem cells may lead to new infertility treatment

A special class of adult stem cells, known as human induced pluripotent stem (iPS) cells, has for the first time been reprogrammed into cells that develop into human eggs and sperm. The research, carried out by members of the University of California, Los Angeles (UCLA)’s Broad Stem Cell Research Center, was published in the January 27 online edition of the journal Stem Cells. Derived from adult body cells that have been engineered to return to an embryonic state, iPS cells have the ability to become every cell type in the human body – a characteristic they share with embryonic stem (ES) cells. In this study the iPS cells were coaxed into forming the germ line precursor cells that are capable of giving rise to sperm and eggs. ‘This finding could be important for people who are rendered infertile through disease or injury’. said Amander Clark, the senior author of the study. ‘We may, one day, be able to replace the germ cells that are lost, and these germ cells would be specific and genetically related to that patient’. Many infertile couples would see this process as preferable to using eggs or sperm from a donor who would then become one of the child’s genetic parents. However, Clark cautioned that scientists are still many years from offering treatments involving iPS cells to infertile patients. There are many uncertainties and dangers that need to be resolved. For example, the process of reprogramming involves using viruses to deliver genes to the cells, potentially increasing the likelihood of genetic abnormalities and cancers. Crucially, Clark’s team found that the germ line cells derived from iPS cells did not perform certain key regulatory processes as well as those generated from ES cells. The associated increased risk of chromosomal errors, or abnormal growth, could have serious health consequences for any child conceived using egg or sperm obtained in this way. Therefore Clark believes that it is vital that research using human ES cells continues. These cells can be derived from left over embryos used during in vitro fertilisation, and would otherwise be destroyed, yet their use is controversial and the topic remains fiercely debated.

Sources : Los Angeles Times, IVF News

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Sperm From Female Stem Cells

 

British scientists have created early-stage, human sperm from female stem cells, according to a news reportin New Scientist magazine. It is claimed that the research will pave the way for same sex couples to have children that are genetically their own. However, other scientists are sceptical that this procedure would ever be possible.
Professor Karim Nayernia at the University of Newcastle initially fertilised mice with sperm derived from embryonic stem cells (ESCs) in 2006, which gave rise to seven pups, six of which survived. In more recent work, he took human male stem cells from bone marrow and formed ‘spermatogonia’, primitive sperm cells that can form mature sperm cells by going through a process called meiosis. Nayernia has now apparently done the same using human female stem cells, work that has yet to be published.
The next stage in the process would be to make these primitive sperm cells undergo meiosis, which Nayernia claims he has started to do. The result could be that female eggs are fertilised by ‘female’ sperm, thereby eradicating the need for male gametes. However, Dr Robin Lovell-Badge, a stem cell expert at the National Institute of Medical Research in London, does not think the approach will work. He told the Telegraph newspaper that the ‘presence of two X chromosomes is incompatible with this. Moreover they need genes from the Y chromosome [from the male sperm] to go through meiosis. So they are at least double damned’. Safety issues have also been raised, since the mice pups in Nayernia’s initial study had health problems.
A Brazilian team of scientists lead by Dr Irina Kerkis at the Butantan Institute in Sao Paolo also claim to have made sperm and eggs from male mouse ESCs, and are currently starting to take the work into human cells. The research brings hope to people dealing with infertility, a problem that affects one in six couples, although scientists say the process is still in its infancy and treatments are a long way off.
There is also potential to use ‘induced pluripotent stem cells’, stem cells derived from human skin cells, as a starting point for the process. This could enable gay men to donate skin cells that would be used to create stem cells from which eggs could be formed. The eggs could then be fertilised using sperm from his partner, and placed in a surrogate mother.
Greg Aharonian, a patent analyst in the US, is trying to patent the technology behind ‘female’ sperm and ‘male’ eggs. A self-proclaimed ‘troublemaker’, he wants to undermine the argument that marriage should remain heterosexual because its main purpose is procreation.
The controversial developments have provoked mixed responses in the UK and US. Mike Judge from the Christian Institute faith group says that ‘children need male and a female role models’. Many religious groups still oppose gay marriage. Josephine Quintavalle, from the pro-life lobby group Comment on Reproductive Ethics, says: ‘we are looking at absurd solutions to very obscure situations and not addressing the main issue. Nobody is interested in looking at what is causing infertility – social reasons such as obesity, smoking and age’.

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Insulin-secreting cells produced by stem cells


Scientists in the US have derived insulin-producing cells from human embryonic stem cells (hESCs), and have successfully implanted them into mice. The achievement, reported last week in the journal Nature Biotechnology, could help push forward research into therapies for diabetes. Type 1 diabetes, and some forms of type 2 diabetes, are caused by a deficiency of pancreatic beta cells. These are cells that produce insulin, the hormone that helps control blood glucose levels, and are part of clusters of hormone-producing cells in the pancreas called the islets of Langerhans. The disease is characterised by a lack of insulin and subsequent misregulation of blood glucose, a condition that can be fatal. Diabetes is currently the seventh leading cause of death in the US, with 200,000 deaths reported per year.
The scientists at Novocell Inc. in San Diego, led by Dr Emmanuel E. Baetge, the chief scientific officer, derived immature precursor pancreatic beta cells from hESCs. They then implanted them into mice whose own beta cells had been destroyed by chemical treatment. After 90 days, the mice had switched the precursor cells into mature beta cells that produced insulin again, which helped control blood glucose. The implanted cells were said to be ‘functionally and morphologically similar’ to normal beta cells.Transplanting human islet cells into diabetic patients from donated pancreases has been proven to help treat the symptoms of diabetes, but this technique relies upon donations, of which there is not a consistent supply. There is also a risk of transplanting infected or contaminated cells. The new technology could provide a readily available and renewable bank of clean cells for treatment when the patient needed it.
The scientists say that there is a long way to go before this can be taken into humans. There are safety issues still apparent as some of the mice in the study developed tumours, called ‘teratomas’. Some critics are also concerned with whether the transplanted hESC derived cells would be destroyed by the recipient’s body, just as their own original beta cells were.Experts, however, are in no doubt that this is an exciting advancement. ‘This for the first time validates that you can use human embryonic stem cells to produce fully functional human islets’, says Dr Baetge.

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Stem-Cell Tourism condemned

The increasing problem of ‘stem-cell tourism’ – patients travelling to developing countries seeking costly and unproven stem cell treatments – have prompted leading experts to join in an international effort to establish standards for the development of stem cell treatments. The 30-member committee, comprised of scientists and ethicists from 13 nations, was to release a draft guide at the International Society for Stem Cell Research (ISSCR) annual meeting in Philadelphia last week but discussions have delayed it. They now hope to have a draft ready in one month, said George Daley, president of the ISSCR, which created the task-force committee. The committee will also collaborate with patient groups to publish a shorter document of frequently asked questions to help explain the guidelines and assist individuals to evaluate the merits of advertised therapies.
The therapeutic benefit of stem cells – cells which can regenerate damaged tissue and organs – are still many years away. Daley told a news conference that he is particularly concerned that stem cell science in its infancy is ‘fertile ground for exploitation’ because so little is yet understood but the therapeutic potential is so great and ‘patients who are desperate will misunderstand the amount of progress in the field’ and become vulnerable to ‘snake oil’ ‘medical fraud’. ‘We need to be strong in condemning this kind of medical tourism’, agreed Olle Lindvall, committee co-chair and neurologist at the University of Lund in Sweden.
The guidelines will provide criteria for the characterisation and production of stem cells eventually intended for human transplantation as well as the level of evidence that should be required through lab and animal studies before conducting human clinical trials. While the guidelines are not legally binding, the members hope they will serve as regulatory guideposts for countries to translate into laws that protect patients from being swindled or harmed.
The only proven stem cell therapies are for blood disorders, certain cancers and rare immune deficiencies. Yet, a proliferation of internet websites offer costly stem-cell nostrums as cure-alls for conditions ranging from Parkinson’s disease, stroke and paralysis to anti-ageing treatments available in countries including China, Thailand and Costa Rica which Daley dismisses as ‘snake oil’. None of these therapies are scientifically proven to be safe and effective, according to Lindvall.
The numbers of individuals travelling for stem cell treatment is unknown but a team led by Timothy Caulfield at the University of Alberta ‘s Health Law Institute in Canada, surveyed 32 websites offering treatments – identified from the media and Google searches – and found that only one site described the procedure as experimental and 26 sites advertised it as being routine. Only four websites referred to peer-reviewed studies. Additionally, the treatments are expensive – 13 sites detailed prices and the average cost for a course of treatment is over INR 360,000 but if combined with cosmetic and lifestyle procedures offered then the figure increases to roughly INR 10,80,000. Insoo Hyun, a bioethicist at Case Western Reserve University in Ohio and co-chair of the committee agrees that a ‘strong statement’ is required and the wording of the draft in progress reflects this: ‘The ISSCR condemns the administration of stem cells or their direct derivatives to… patients as unproven medical innovation outside of a clinical trial, particularly when patients in these circumstances are charged for advertised medical services’. It is questionable whether these guidelines will really deter desperate individuals. Many advocacy groups offer patient guidelines and most countries, developing or otherwise, already have regulations for allowing research to enter clinical trials (albeit with varied levels of enforcement). However, most of these rules are non-specific and were created before stem cell treatments entered the limelight.

 

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Disgraced Stem Cell Scientist to Offer Dog Cloning Services

US company BioArts International has teamed up with disgraced South Korean scientist Hwang Woo-Suk to offer dog cloning services to the public. Five dog owners will be given the opportunity to have their pet cloned in a worldwide auction on 18 June this year, where bidding will start at $100,000. BioArts chief executive, Lou Hawthorne, had previously attempted to
commercially exploit cloning technology by offering customers the chance to clone their pet cats for $50,000, through a company named Genetic Savings. The project failed and Genetic Savings ceased operations in 2006, but Hawthorne says the technology for the dog cloning project – named ‘Best Friends Again’ – has since improved. BioArts claims it is the only company with the legal rights to clone dogs, using a technique pioneered by researchers at the Roslin Institute in the UK, used to create Dolly the sheep. To do this, it has enlisted the help of the SooAm Biotech Research Foundation, headed by Hwang.
The decision is controversial, however, as Hwang is currently on trial in South Korea for fraud and embezzlement, after his claim to have created the world’s first cloned human embryonic stem cell line was revealed to be fraudulent. It is also alleged that he used eggs obtained from a junior researcher working on his team, breaching international ethical codes of practice. ‘I know the association with Dr. Hwang is going to be controversial,’ said Hawthorne, adding ‘one of the contradictions of Dr
Hwang is that he made mistakes on his human stem-cell research, and he’s the first to admit that.’
Of the discredited research carried out by Hwang at Seoul National University (SNU) only the creation of a cloned dog named Snuppy, a male Afghan hound, was found to be genuine. Since then Hwang has successfully cloned three female Afghan hounds, and the cloning of grey wolves by his team at the SNU has also been upheld as genuine. ‘Our main concern is simply
he’s the best when it comes to dog cloning,’ said Hawthorne, ‘and for that reason it behooves us to work with him’. Although the dogs will be genetically identical, the cloned animals will not behave in the same way as their twin, and bioethicist Arthur Caplan, of the University of Pennsylvania, said owners should not expect to get their old dog back. ‘People believe they’re going to get their pet back through cloning, but the new cloned dog won’t know the old pet’s tricks’, he said. ‘It’s a false promise to say you can get your pet back’, he warned.
It is likely that the successful bidders will be refunded if the cloning process is unsuccessful or if the cloned animal does not meet their expectations. BioArts has said it will not spend the money unless the dog has been ‘signed off’. All the dogs will be examined by a veterinarian prior to delivery and come with one year’s health warranty.

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