Scientists in S Korea have cloned 30 human embryos. They hope to obtain cells that could eventually be used to treat disease.
The took the genetic material from normal cells in women donors and combined it with their eggs.
This was done at the Seoul National University by Suk Hwanf and his team.
The embryos were then developed to produce stem cells. These stem cells can divide into any tissue in the body.
These cells will (it is hoped) replace those which have failed, for example, in patients with Alzheimer's disease.
'Because these cells carry the nuclear genome of the individual, after differentiation they could be expected to be transplanted without immune rejection for treatment of degenerative disorders. Our approach opens the door for the use of these specially developed cells in transplantation medicine.' said Professor Hwang.
His research is being published online by the journal Science (Science Express web site).
Mice proof
There have been claims in the past for the creation of human embryo clones to study so-called stem cells - many of them disputed.
But no group has reported producing so many early-stage clones and seen their development progress to such an advanced stage.
The work has also been subjected to the rigorous scrutiny of independent scientists before publication in a major journal.
'These are the most advanced human embryo clones yet produced,' Professor Hwang told BBC News Online.
The team says it sought approval for its work from an ethical review board and obtained informed consent from its women donors before proceeding with the work.
Thirty embryos
The team tells Science Express how it used 242 eggs in its experiments taken from 16 women.
In each case, material was transferred from the nucleus of a non-reproductive (somatic) cell, containing the woman's genetic blueprint, into a nucleus-free egg from the same donor.
Following this transfer, factors within the host egg's exterior, or cytoplasm, are believed to have reprogrammed the new nuclear contents by activating versatile embryonic genes, while silencing the more limited adult somatic cell genes.
In total, 30 embryos - exact genetic copies of their female donors - were then cultured to the so-called blastocyst stage at which stem cells could be extracted.
These special cells were seen to divide into all three of the main tissue types found in the human body, the researchers report.
The cells were even transplanted into mice to show they could differentiate into still more specific cell types, offering further proof of their 'pluripotency'.
The stated intention is to study human embryonic stem cells to see how they could be used as a therapeutic tool to treat disorders, such as diabetes, osteoarthritis, and Parkinson's disease, among others, in which tissues in the body have begun to fail.
Non-egg future
Editor-in-chief of the journal Science, Donald Kennedy, said: 'The potential for embryonic stem cells is enormous, but researchers still must overcome significant scientific hurdles.'
And he added: 'These results seem promising. But, it's important to remember that cell and tissue transplantation and gene therapy are still emerging technologies, and it may be years yet before embryonic stem cells can be used in transplantation medicine.'
Addressing ethical concerns, he also called for a worldwide ban on activities which would seek to use this technology to create living children.
Professor Hwang, whose expertise has been developed in animal cloning, said any attempt to produce a baby would be 'crazy'.
'We will never try to produce cloned human beings,' he said.
'During animal cloning, we experienced so many difficulties and dangers with deformities, especially in the internal organs.'
Commenting on the Korean work, Roger Pedersen, professor of regenerative medicine, at the University of Cambridge, UK, told BBC News Online: 'The present work has substantially advanced the cause of generating transplantable tissues that exactly match the patient's own immune system.
'These researchers' findings also make it possible to learn how to reprogramme the human genome to an embryonic state.
'This will likely accelerate the development of alternative ways of reprogramming human cells, which could in the future diminish the need to use human eggs for this purpose.'
American Association for the Advancement of Science
The embargo on this press release has been lifted ahead of schedule.
SEATTLE, WA--New research - published by Science Magazine within the Science Express Web site and released today at the 2004 AAAS Annual Meeting -- may be a first step toward methods for treating diabetes, osteoarthritis, Parkinson's and other diseases, by producing replacement cells unlikely to trigger immune-system rejection.
Transplantation medicine based on stem cells remains a distant hope for now, Science editors cautioned. But, the Science study describes intriguing early results:
For the first time, researchers have reported the development of versatile 'pluripotent' human embryonic stem cells, potentially capable of becoming any cell in the body, from a cloned human blastocyst.
The stem cells were harvested from a blastocyst produced by transferring the nucleus of a non-reproductive ('somatic') cell, containing a woman's genetic blueprint, into a nucleus-free egg from the same donor.
Following this transfer, factors within the host egg's exterior, or cytoplasm, reprogrammed its new nuclear contents by activating versatile embryonic genes, while silencing the more limited adult somatic cell genes. Researchers were then able to collect embryonic stem cells from the resulting cell mass inside the cloned blastocysts.
In theory: 'Because these cells carry the nuclear genome of the individual, after differentiation they could be expected to be transplanted without immune rejection for treatment of degenerative disorders,' reported Woo Suk Hwang of Seoul National University in Korea.
'Our approach opens the door for the use of these specially developed cells in transplantation medicine.'
Embryonic stem cells have previously been produced with cells from mice using the same method, called 'somatic cell nuclear transfer.' But, achieving this trick with human cells posed unique challenges, said Donald Kennedy, Science's Editor-in-Chief.
The researchers attribute their apparent success to the use of extremely fresh donor eggs, stringent timing protocols, and a special method for gently extruding rather than suctioning the DNA-spindle complex from eggs. Suctioning the DNA may damage spindles, possibly causing chromosomal defects called aneuploidy, they noted.
Hwang and colleagues developed the stem cell line, SCNT-hES-1, after collecting 242 eggs from 16 unpaid volunteers who had signed informed-consent agreements. From these eggs, scientists then cultured 30 blastocysts to obtain 20 suitable inner cell masses. By tweaking the amount of time that elapsed between the transfer of the nucleus and the activation of the newly transplanted genetic material, the team was able to optimize their results:
A two-hour delay seemed to work best, so that 20 percent of all reconstructed eggs formed blastocysts. From the inner cell mass of these blastocysts, a single human embryonic stem cell line was obtained.
The resulting stem cells differentiated into all three of the main tissue types that appear at the beginning stages of development, researchers reported. When transplanted into mice, the stem cells differentiated into still more specific cell types, offering further proof of pluripotency.
Interestingly, the research team harvested eggs as well as somatic cells from the same donors: Nuclear material from the somatic cell was transferred into the nucleus-free or enucleated egg of the same woman.
This unusual experimental design may be more effective than person-to-person transfers because it offered greater compatibility between the genetic components that were fused together.
But, were the stem cells truly derived from the transferred nucleus, or were they the result of an accidental 'parthenote'--an artificially induced blastocyst resulting from an egg that began to spontaneously divide?
To support their claim that the resulting stem cells came from the transplanted nucleus, Hwang's team completed DNA fingerprinting analysis, and also checked the expression of imprinted genes.
The results were consistent with stem cells resulting from transplantation.
Many questions remain, Science's Donald Kennedy said: 'The potential for embryonic stem cells is enormous, but researchers still must overcome significant scientific hurdles,' Kennedy remarked.
'These results seem promising. But, it's important to remember that cell and tissue transplantation and gene therapy are still emerging technologies, and it may be years yet before embryonic stem cells can be used in transplantation medicine.'
The research also raises policy and ethical questions, Kennedy noted, since blastocyst-derived stem cells for tissue repair or transplantation might exacerbate pressures on egg donors in some regions.
The prospect of using cloned human blastocysts to produce new embryonic stem cells lines also is likely to provoke further controversy, he added. 'There is widespread consensus among all responsible, mainstream scientists--including the authors of this paper and AAAS, publisher of Science Magazine--that any attempt to clone a human being would be highly dangerous and wrong, and therefore, all reproductive cloning should be banned,' Kennedy said.
'But, the generation of stem cells by somatic cell nuclear transfer methods involving the same individuals may hold promise for advances in transplantation technology that could help people affected by many devastating conditions.'
In addition to Hwang, authors on this Science paper were Young June Ryu, Eul Soon Park, Eu Gene Lee, Hyun Yong Chun, Byeong Chun Lee, Sung Keun Kang, Curie Ahn and Shin Yong Moon, all of Seoul National University; as well as Jong Hyuk Park and Sun Jong Kim of Mizmedi Hospital in Seoul; Ja Min Koo of Gachon Medical School; Jung Hye Hwang of Hanyang University; Ky Young Park of Sunchon National University; and Jose B. Cibelli of Michigan State University.
The American Association for the Advancement of Science (AAAS) is the world's largest general scientific society, and publisher of the journal, Science (www.sciencemag.org). AAAS was founded in 1848, and reports some 265 affiliated societies and academies of science, serving 10 million individuals. Science has the largest paid circulation of any peer-reviewed general science journal in the world, with an estimated total readership of one million. The non-profit AAAS (www.aaas.org) is open to all and fulfills its mission to 'advance science and serve society' through initiatives in science policy; international programs; science education; and more. For the latest research news, log onto EurekAlert!, www.eurekalert.org, the premier science-news Web site, a service of AAAS.
MEDIA NOTE: A newsbriefing on this research will take place at 11:00 a.m. Pacific Time, Thursday, 12 February, during the AAAS Annual Meeting in Seattle, in the Eliza Amphitheater, Grand Hyatt. Further, these and other speakers will take part in a symposium titled, 'Stem Cell Science in the Service of Society,' at 2:30 p.m. Monday, 16 February, Sheraton Hotel, Second Floor, Grand Ballroom C. Press registration is in the AAAS Press Center in Leonesa I of the Grand Hyatt Hotel.
AAAS is the world's largest general scientific society, dedicated to 'Advancing science � Serving society.'
Contact: Ginger Pinholster
gpinhols@aaas.org
206-774-6330
Stem cell research has been given a boost after a new study shows a link between the controversial technique and couples undergoing IVF treatment.
The survey found that 57% of IVF couples would consent to their surplus embryos being used for stem cell research - because they receive better information on the issue.
Medical experts say the number of couples handing over surplus embryos depends upon the quality of information about the needs and benefits of stem cell research given.
Stem cell research has been the target of huge criticism from pro-life campaigners and religious communities who believe embryos are already a human life and should be treated as such.
Professor Alison Murdoch, chairman of the British Fertility Society said: 'Our results are encouraging as they show that couples undergoing IVF understand the need and benefits of embryo research, probably because they have access to good information that the majority of the population do not.
'When people understand this issue they tend to look on it favourably.
'Scientists should not be afraid of engaging the public on this issue.'
Clare Brown, chief executive of Infertility Network UK, added: 'The results of this study highlight the fact that couples are keen to assist others while going through what is an extremely difficult, both physically and emotionally, treatment for themselves personally.
'The key word for couples is obviously `information'.'
Meanwhile, new research shows that sperm counts have dropped by almost a third in a decade.
Drug use, alcohol, smoking and obesity are among the factors most frequently blamed.
Each attempt at IVF treatment costs about �3,000 and the NHS funds only one in five of these attempts.
It is expected that a new recommendation will entitle thousands of women aged between 23 and 39 to free IVF treatment.
A group of researchers from The Scripps Research Institute (USA) has identified a small synthetic molecule that can induce a cell to undergo dedifferentiation--to move backwards developmentally from its current state to form its own precursor cell.
This compound, named reversine, causes cells which are normally programmed to form muscles to undergo reverse differentiation--retreat along their differentiation pathway and turn into precursor cells.
These precursor cells are multipotent; that is, they have the potential to become different cell types. Thus, reversine represents a potentially useful tool for generating unlimited supply of such precursors, which subsequently can be converted to other cell types, such as bone or cartilage.
'This [type of approach] has the potential to make stem cell research more practical,' says Sheng Ding, Ph.D. 'This will allow you to derive stem-like cells from your own mature cells, avoiding the technical and ethical issues associated with embryonic stem cells.'
Ding, who is an assistant professor in the chemistry department at Scripps Research conducted the study--to be published in an upcoming issue of the Journal of the American Chemical Society--with Peter G. Schultz, Ph.D., who is a professor of chemistry and Scripps Family Chair of Scripps Research's Skaggs Institute of Chemical Biology, and their colleagues.
Regenerative Medicine and Stem Cell Therapy
Stem cells have huge potential in medicine because they have the ability to differentiate into many different cell types--potentially providing doctors with the ability to produce cells that have been permanently lost by a patient.
For instance, the damage of neurodegenerative diseases like Parkinson's, in which dopaminergic neurons in the brain are lost, may be ameliorated by regenerating neurons.
Another example of a potential medical application is Type 1 diabetes, an autoimmune condition in which pancreatic islet cells are destroyed by the body's immune system. Because stem cells have the power to differentiate into islet cells, stem cell therapy could potentially cure this chronic condition.
However bright this promise, many barriers must be overcome before stem cells can be used in medicine. Stem cell therapy would be most effective if you could use your own stem cells, since using one's own cells would avoid potential complications from immune rejection of foreign cells.
However, in general it has proven very difficult to isolate and propagate stem cells from adults. Embryonic stem cells (ESCs) offer an alternative, but face both practical and ethical hurdles associated with the source of cells as well as methods for controlling the differentiation of ESCs.
A third approach is to use one's own specialized cells and dedifferentiate them.
Normally, cells develop along a pathway of increasing specialization. Muscles, for instance, develop after embryonic stem cells develop into 'mesenchymal' progenitor cells, which then develop into 'myogenic' cells. These muscle cells fuse and form the fibrous bundles we know as muscles.
In humans and other mammals, these developmental events are irreversible, and in this sense, cell development resembles a family tree. One wouldn't expect a muscle cell to develop into a progenitor cell any more than one would expect a woman to give birth to her own mother.
However, such phenomena do happen in nature from time to time.
Some amphibians have the ability to regenerate body parts that are severed by using dedifferentiation.
When the unlucky amphibian loses a limb or its tail, the cells at the site of the wound will undergo dedifferentiation and form progenitor cells, which will then multiply and redifferentiate into specialized cells as they form an identical replacement to the missing limb or tail.
In humans, the liver is unique in its regenerative capacity, possibly also involving dedifferentiation mechanism.
The Scripps Research scientists hope to find ways of mimicking this natural regeneration by finding chemicals that will allow them to develop efficient dedifferentiation processes whereby healthy, abundant, and easily accessible adult cells could be used to generate stem-like precursor cells, from which they could make different types of functional cells for repair of damaged tissues.
Reversine is one of the first steps in this process.
However, tissue regeneration is years away at best, and at the moment, Schultz and Ding are still working on understanding the exact biochemical mechanism whereby reversine causes the muscle cells to dedifferentiate into their progenitors, as well as attempting to improve the efficiency of the process.
'This [type of research] may ultimately facilitate development of small molecule therapeutics for stimulating the body's own regeneration,' says Ding. 'They are the future regenerative medicine.'
The article, 'Dedifferentiation of Lineage-Committed Cells by a Small Molecule' is authored by Shuibing Chen, Qisheng Zhang, Xu Wu, Peter G. Schultz, and Sheng Ding and is available to online subscribers of the Journal of the American Chemical Society at: http://pubs.acs.org/cgi-bin/asap.cgi/jacsat/asap/html/ja037390k.html. The article will also be published in an upcoming issue of JACS.
This work was supported by The Skaggs Institute for Research and the Novartis Research Foundation.
Studies in zebrafish lead to better understanding of blood formation and leukemia development
Boston--Researchers at Children's Hospital Boston have isolated a gene responsible for making blood stem cells. The findings appear in today's issue of the journal Nature. The gene, called cdx4, is responsible for establishing the location of blood cell formation in the developing embryo.
Cdx4 works by altering the expression of HOX genes, which are involved in making the body plan. Surprisingly, the authors found that overexpression of cdx4 in zebrafish embryos, or in mouse embryonic stem cells, induces the new production of early blood cells.
'We have been searching for genes in the zebrafish that participate in making blood stem cells,' according to lead author, Leonard Zon, MD., of Children's Hospital Boston.
'Now that we have these genes, we are one step closer to growing more blood stem cells. This will be potentially useful for patients with severe congenital anemias or bone marrow transplantation for cancer,' adds Zon.
Scientists studied a mutant that had a severe anemia because it had few blood stem cells, and also had a tail defect. The zebrafish mutants generally die within seven to ten days after fertilization.
They discovered the mutation in the cdx4 gene, which is associated with the early blood deficiency as well as abnormal developmental patterning, including aberrant hox gene expression.
When researchers injected the mutants with hox genes, such as hoxb7a and hoxa9a, it resulted in almost complete rescue of the deficient blood cells. Another hox gene, hoxb6b showed some improvement, but hoxb8a did not have any effect on the blood defect.
Researchers believe this shows blood cell development is dependent on the proper expression of these hox genes, and that overexpression of these genes can reverse a fatal deficiency in these blood cells.
'These zebrafish findings will allow us to better understand normal blood development, with the hopes of eventually developing more effective treatments for these devastating blood disorders such as leukemia,' says Zon.
Children's Hospital Boston is home to the world's largest research enterprise based at a pediatric medical center, where its discoveries have benefited both children and adults for over 100 years. More than 500 scientists, including seven members of the National Academy of Sciences, nine members of the Institute of Medicine and nine members of the Howard Hughes Medical Institute comprise Children's research community. Founded in 1869 as a 20-bed hospital for children, Children's Hospital Boston today is a 300-bed comprehensive center for pediatric and adolescent health care grounded in the values of excellence in patient care and sensitivity to the complex needs and diversity of children and families. It is also the primary pediatric teaching affiliate of Harvard Medical School. For more information about the hospital visit: www.childrenshospital.org.
Embryonic stem cells have been encouraged to grow into sperm cells for the first time, Japanese scientists report.
The work is very preliminary, and was done in the laboratory with mouse stem cells. The next step would be to see if it can be repeated in live animals.
Stem cells are the basic building blocks of animals, forming in the new embryo and later developing into the various organs and tissues as the fetus grows.
Researchers have grown stem cells into many other types of cells, including egg cells, but this is the first time a sperm cell has been developed, the scientists said.
The work was headed by Toshiaki Noce of Mitsubishi Kagaku Institute of Life Science in Japan. The results are reported in this week's online issue of Proceedings of the National Academy of Science.
Noce and his team incubated the stem cells with other cells that produce a protein called BMP4, which is known to stimulate formation of sperm cells during the development of an embryo. In their laboratory, some of the stem cells began developing into sperm cells within one day, a process that takes three days in the embryo.
Bert Vogelstein, a professor at Johns Hopkins University who headed an Academy panel on stem cells, said the work is 'novel and provides a wonderful example of how new technologies can provide diverse cell types in the test tube that may prove useful for biomedical applications in the future.'
Growing stem cells into other tissues has been hailed as a source of major potential therapies in the future. However, the process is controversial because many stem cells are harvested from discarded embryos.
The Bush administration has limited federal funding for stem cell research to lines of cells that already exist, although new stem cell lines can be developed using private funds and in some other countries.
Study adds to evidence of adult stem cells' promising therapeutic role
BURLINGTON, VT (USA) - For the first time, researchers have demonstrated that adult human stem cell transplantation results in spontaneous cell regeneration in damaged lung tissue.
Published in the August 1 issue of the American Journal of Respiratory and Critical Care Medicine, the study further supports an existing body of research that suggests blood- and marrow-derived stem cells have the capacity to become many different human tissues.
'Many of the body's tissues once thought to be only locally regenerative may, in fact, be actively replaced by circulating stem cells after hematopoietic or blood-forming stem cell transplantation,' says lead author Benjamin Suratt, M.D., assistant professor of medicine and Vermont Lung Center researcher at the University of Vermont College of Medicine.
'This finding is of note not only for its novelty as a regenerative mechanism of the lung, but also for its vast therapeutic implications for any number of lung diseases.'
According to Suratt, the study's findings indicate that circulating stem cells are going into organ tissue and repairing damage, which could have a huge impact on the treatment of such devastating lung diseases as emphysema or cystic fibrosis.
Supported by funding from the National Institutes of Health and a National Center for Research Resources Centers for Biomedical Research Excellence grant, Suratt and his colleagues are currently looking further into what types of cells have the capacity to differentiate and generate a different type of cell, and whether these cells might be used to treat cystic fibrosis.
For more information on research taking place at the Vermont Lung Center at the University of Vermont, go to www.vermontlung.org
To link to the article abstract, go to:
ajrccm.atsjournals.org/cgi/content/abstract/168/3/318
Mike May, of California, had been blind for 40 years since an accident at the age of three where he lost one eye and was blinded in the other.
During that time he had some ability to perceive light, but could not make out form or contrast.
He said he had no visual memories from his early childhood.
The operation transplanted corneal and limbal stem cells into his right eye.
The cornea is the clear part of the outer layer of the eye that covers the iris and the pupil. The limbus is the thin area that connects the cornea and the sclera, the white part of the eye.
Shapes
Researchers followed his recovery in order to study how Mr May learned to see again.
They measured areas such as how he perceived shapes, his spatial awareness and how he saw 3D images.
When he was tested five months after surgery, the patient was able to perceive slight movements of a bar and was able to recognise simple shapes.
Two years after the surgery, Mr May was able to see form, colour and motion almost normally.
However, his 3D perception and face and object recognition was still severely impaired.
Mr May could only identify around a quarter of common objects shown to him.
And he was also only able to tell if an unfamiliar face was male or female 70% of the time.
His perception of motion was found to be the most well-preserved visual faculty.
Frightened
But Mr May was not fully comfortable with his newly gained sight.
Before the operation he had been a keen skier, using verbal directions as a guide.
But after he recovered his sight, he was frightened he would crash into something.
Over two years, he has learnt to use shading patterns on the snow to estimate the shape of the slope.
Mr May is also nervous of crossing the road, where he was confident of doing so while blind.
He said: 'The difference between today and over two years ago is that I can better guess what I am seeing. What is the same is that I am still guessing.'
The details of Mr May's case are published in the journal Nature Neuroscience.
The body's master cells can repair the damage caused by a heart attack, a study suggests.
Tests on rats have shown that stem cells can restore up to 90% of the heart's ability to pump blood around the body, which is often reduced following an attack.
Stem cells, which can be obtained from bone marrow, are unique in that they have the potential to turn into any other cell in the body.
Doctors have injected these cells into a small number of patients with heart disease. However, the results of these trials are not yet known.
This latest study adds to the growing body of evidence that stem cells could provide real hope to patients with heart problems.
Difficult procedure
Up until now, the technique has proved problematic because the stem cells tended to die shortly after being transplanted.
This has meant that the stem cells have not been able to turn into new muscle, replacing tissue that has died as a result of a heart attack.
Dr Victor Dzau and colleagues at Brigham & Women's Hospital in Boston, United States, have tried to get around this problem by engineering these cells to enable them to survive longer.
They added the Akt gene to cells in the laboratory. Akt is a protein that prevents cell death.
These engineered cells were then injected into the hearts of rats, which had had a heart attack.
Tests showed that cells with this gene were much more likely to survive compared to other stem cells.
The treatment restored between 80% and 90% of the heart's volume.
Writing in the journal Nature Medicine, they said it also dramatically improved the heart's ability to pump blood around the body.
'Stem cells genetically enhanced with Akt can repair infracted myocardium, prevent remodelling and nearly normalize cardiac performance,' they said.
Doctors elsewhere in the US announced in April that they had carried out stem cell transplants on 15 patients with advanced heart disease.
One of these patients died 14 weeks later. Doctors at the Texas Heart Institute have yet to reveal how the other patients have fared.
They are also considering carrying out much larger trials. If successful, they could pave the way for stem cell transplants for other patients with heart disease around the world.
The European Commission has said the EU should fund research which involves harvesting stem cells from frozen human embryos - but not in countries where the technique is banned.
However those countries may still oppose the introduction of the new rules on moral grounds.
Sweden, Finland, Greece, the Netherlands and Britain allow stem cells to be harvested from 'spare' IVF embryos.
But taking stem cells from embryos is illegal in countries such as Germany, France, Ireland and Spain and blocked elsewhere.
The European Commission hopes the rules can be introduced by 31 December this year when a moratorium on EU funding for stem cell research ends.
But all member states must approve the rules before they can be introduced.
Laboratory sources
Supporters of stem cell research say it could hold the key to cures for a wide range of serious diseases, including Alzheimer's and Parkinson's.
Stem cells are cells at an early stage of development which have the potential to turn into many different types of tissue.
But critics say existing sources of stem cells - so-called 'lines' which can be grown in laboratories, can supply enough for research and would eradicate the need for embryos to be used in research.
In Germany, the law states research on stem cells is only allowed if they were imported and existed before 1 January 2002.
It is understood Germany wants the EU to introduce similar rules.
The European Commission has set a cut-off date of 27 June 2002 for when embryos must have been created - but it does not set a date for when stem cells should have been created by.
Foresight
EU Research Commissioner Philippe Busquin said the main aim was to stop a 'brain drain' of the brightest scientists leaving Europe to work in countries like the US, Australia and Singapore.
He said: 'Europe is in relatively weak position.
'Obviously there are ethical concerns. But the real question is 'Are we able to have excellence in this field in Europe?'.'
He said countries could continue to choose whether they funded embryonic stem cell research themselves, but that the EU felt it was important to encourage as much research as possible.
Sir George Radda, chief executive of the Medical Research Council, said: 'The decision to set a cut-off date for which embryos can be used is limiting and may mean fewer high-quality embryos available for research, but we recognise compromise was needed given the disparate views of member states.
'Overall we're pleased that the Commission has recognised the importance of granting funding to allow researchers to generate stem cells using freely donated embryos left over from IVF research.
'The MRC sees stem cell research as a key research priority over the coming decades and the UK government has had the foresight to put in place legislation that will enable ethical and beneficial research into heath and human disease to be carried out.
'It's good to see this being echoed in EC policy, as we are on the brink of real medical progress.'
A spokesman for the Parkinson's Disease Society said: 'The use of stem cell research offers real hope that lost dopamine-producing cells can be replaced with new healthy cells.
'This could be the first treatment to reverse the symptoms of Parkinson's and could therefore effectively lead to a cure.
Embryonic stem cells (ESCs) have huge potential use for scientists because they have the ability to turn into many different forms of tissue. However, their use remains highly controversial.
Britain has allowed scientists to conduct embryonic stem cell experiments, but they could soon be banned by the European Union, and the US is still considering the issue.
New Scientist magazine reports that the US team harvested cells from human embryos at an early stage of development.
They then manipulated them in the laboratory to turn them into specialised cells that form myelin, the insulating layer than surrounds nerve fibres.
These cells were transplanted into paralysed rats with bruised spines.
After nine weeks, the rats fully regained the ability to walk.
Analysis of the rats' spinal cords showed that the cells had wrapped themselves around nerve cells and formed new myelin sheaths.
They also secreted substances that appeared to have stimulated the formation of new nerves.
Recent injuries
Dr Hans Keirstead and his team from the University of California at Irvine now plan to use the same technique to treat human patients who have sustained recent spinal cord injuries.
However, treating people who have been paralysed for years or suffer from degenerative nerve diseases will be far more difficult.
Scientists have tried using adult stem cells derived from bone marrow and nerve cells repair damaged spines.
But Thomas Okarma, of US biotech company Geron Corporation which funded the new research, believes only ESCs stand a real chance of success.
They are more versatile than adult stem cells, and, unlike them, can be mass-produced.
Mr Okarma said: 'At this moment, there is very little hard evidence that a bone marrow stem cell can turn into anything but blood or that a skin stem cell can become anything but skin.
Royal Society Response To Joint Committee Report On Draft Human Tissues And Embryos Bill, UK
0 ความคิดเห็น ที่ 04:39
"We hope that the new legislation permits the creation of all types of human-animal embryos for research, under the control of the relevant regulatory authority. It is crucial that regulators are allowed to do the job they were created to undertake. Clarifying the remits of such authorities will streamline the licensing process which is essential for fast moving scientific fields such as stem cell research."
The Royal Society is an independent academy promoting the natural and applied sciences. Founded in 1660, the Society has three roles, as the UK academy of science, as a learned Society, and as a funding agency. It responds to individual demand with selection by merit, not by field. As we prepare for our 350th anniversary in 2010, we are working to achieve five strategic priorities, to:
-- Invest in future scientific leaders and in innovation
-- Influence policymaking with the best scientific advice
-- Invigorate science and mathematics education
-- Increase access to the best science internationally
-- Inspire an interest in the joy, wonder and excitement of scientific discovery
http://www.royalsoc.ac.uk
Missouri's Constitutional Amendment Protecting Stem Cell Research Encounters 'Political, Financial Roadblocks,' New York Times Reports
0 ความคิดเห็น ที่ 04:34
A constitutional amendment approved by Missouri voters in November 2006 that was expected to expand and protect human embryonic stem cell research in the state has "run into political and financial roadblocks, putting the future of the research in doubt," the New York Times reports. According to the Times, the debate over the amendment has become a "fight over what constitutes 'cloning.'"
Supporters of the amendment say that it bans human cloning, which is defined in the amendment as an act that could result in a pregnancy and the creation of a human fetus inside a woman's uterus. Opponents say that cloning is the replication of cells, regardless of implantation in the uterus. Some state lawmakers who oppose the amendment said they will continue to fight it by introducing new bills that would ban some types of stem cell research.
"We think it's a false distinction to say that a clone exists only based on geography," Pam Fichter, president of Missouri Right to Life, said, adding that the group supports "ethical stem cell research, and we think cloning was misrepresented to voters. We know that a majority of Missourians oppose cloning." Donn Rubin -- chair of the Missouri Coalition for Lifesaving Cures, which led efforts to pass the amendment -- said that reproductive cloning was a major concern among voters. "What we protect is a very promising form of medical research that involves cells in a lab dish, not something that involves pregnancy," Rubin said.
Jaci Winship, executive director of Missourians Against Human Cloning, said the group is considering the possibility of a new initiative against the amendment, perhaps as soon as next year. Members of MRTL have been gathering signatures and contributions for the effort, the Times reports. According to Rubin, MCLC has continued raising money to prepare for another fight over the amendment.
Future of Research
According to the Times, although legislative efforts have failed so far, the "uncertainty" of the research's future in the state has made it difficult for facilities to attract stem cell specialists (Davey, New York Times, 8/10).
Many scientists who considered moving to Missouri to conduct stem cell research will not come to the state because of the uncertainty over whether the legislation will be overturned. The Stowers Institute for Medical Research in late July canceled plans to expand in Kansas City, Mo., because it was unable to recruit top stem cell researchers. The institute also transferred a large portion of its $2 million endowment to Delaware because the political climate in Missouri was too hostile (Kaiser Daily Women's Health Policy Report, 8/1).
Kevin Eggan, an assistant professor of molecular and cellular biology at Harvard University, said he strongly considered moving to Stowers but delayed his plans. "Everybody hoped that Missouri was going to be a good test case," Eggan said, adding, "It was exciting to us that stem cell research was being voted in a state which has very restrictive abortion laws. But it has turned out to be a big disappointment."
Sen. Chuck Graham (D) said, "For a bright shining moment in time, we were moving ahead as a state to protect research." He added, "But now the other side wants to walk away, not only from stem cell research, but all research. Their attitude now is, if there's a beaker or a Petri dish involved, we're not going to fund it." Rep. Jim Lembke (R), who opposes embryonic stem cell research and proposed legislation outlawing elements of the research, said, "As people are educated about this issue, they come around" (New York Times, 8/10).
"Reprinted with permission from http://www.kaisernetwork.org. You can view the entire Kaiser Daily Health Policy Report, search the archives, or sign up for email delivery at http://www.kaisernetwork.org/dailyreports/healthpolicy. The Kaiser Daily Health Policy Report is published for kaisernetwork.org, a free service of The Henry J. Kaiser Family Foundation . © 2005 Advisory Board Company and Kaiser Family Foundation. All rights reserved.
PATIENT EXPERIENCE – ATAXIA
George's Blog: http://www.georgearruda.blogspot.com/
NAME: George ArrudaGeorge Arruda
COUNTRY: Canada
AGE: 33
DIAGNOSIS: Sporadic Spinocerebellar Ataxia 3, Machado-Joseph Disease (MJD) (May 2004)
REASON FOR COMING FOR TREATMENT: George was diagnosed with SCA type 3 - Machado-Joseph Disease (MJD) in January of 2002. His father and grandfather also had SCA3. He had a fairly fast progression since the onset of the disease. He had heard about Kim Poor having success with the treatment and decided he wanted to try the treatment as well.
TREATMENT: Umbilical Cord Stem Cell and Nerve Growth Factor Injections with Rehabilitation Therapy
START OF THE TREATMENT: January 1, 2007
BEFORE THE TREATMENT: He had severe loss of balance and coordination, double vision, dizziness, and choking problems. He felt pain and weakness in his legs as well as lack of feeling parts of in his legs. He had eye spasms.
AFTER THE TREATMENT: He regained feeling in his legs. He had less dizziness or “buzz” in his head. His balance and walking improved considerably. He could speak faster.
Jan 3rd (Before): Parallel Walking, Rollator Walking, Walking with Help, Throwing Ball
Jan 10th (One Injection): Parallel Walking 1, Parallel Walking 2, Arms Out Walking
Jan 19th (Three Injections): Walking
Jan 23rd: (Four Injections): Walking Slope
Jan 29th: (Five Injections): Walking Arms Out Narrow
Jan 30th: (Five Injections): Walking Stairs
Jan 31st: (Five Injections): Walking Arms Out Slope, Throwing Ball, Walking Narrow, Walking, Summary, About Staff and Hospital
Update (Feb 18 - from an Email):
George is doing well. The walker is gathering dust as it just sits unused since our return. George is feeling stronger, and has not been sick, despite the fact that I came down with a nasty two week long cold. He managed to avoid it. He is able to get up and get going earlier in the morning, and his speech has been clearer and people have commented on how much easier he is to understand. He is not choking on his meals as often. He is exercising a little bit, but we still need to figure out some kind of a routine. For now he is doing a little bit on the treadmill each day and walking short distances.
PATIENT INTERVIEW – ALS
NAME: Kelly Reynolds
COUNTRY: U.S.A.Kelly Reynolds
AGE: 39
DIAGNOSIS: Bulbar ALS – January, 2005
REASON FOR COMING FOR TREATMENT: First symptoms started in June 2004. The disease progressively got worse until right before the treatment when he was confined to a wheelchair and had limited use of his hands.
TREATMENT: Umbilical Cord Stem Cell and Nerve Growth Factor Injections with Rehabilitation Therapy]
START OF TREATMENT: February 12,
2006 BEFORE THE TREATMENT: He could not get up out of his wheelchair without assistance and would otherwise risk losing his balance. He could only raise his hands to chest when laying on a bed. He had trouble swallowing. He could not move his facial muscles well or stick out his tongue. He was taking Baclofen, 10 mg, three times a day to prevent muscle spasticity. See Videos - Interview , Kelly Stands Up and Kelly Adjusts His Wheelchair
AFTER THE TREATMENT: He had increased mobility in his hands. He could get out of his wheelchair by himself. He could walk on his own. He had an easier time swallowing. He could move his facial muscles when having a shave. He could stick out his tongue. He could turn his hands out more and move them out to the sides more. He only needed to take Baclofen 10mg once every one or two days. OTHER NOTES: Kelly was on a high protein diet and taking a cocktail of medicines including the experimental drug IGF which he feels may have helped to make the stem cells more effective more quickly. When Kelly came for the treatment, he did not bring his IGF but was able to substitute HGH for it. HGH raises the level of IGF in the body. Soon after hearing that Kelly was taking HGH, the other ALS patients wanted it too.
PATIENT EXPERIENCE - BRAIN INJURY
NAME: Lukas Nguyen Lukas
COUNTRY: U.S.A.
AGE: 3 yrs
DIAGNOSIS: Traumatic brain injury (TBI) leading to Cerebral Palsy, diagnosed February 12, 2005
See here for a full youtube video documenting Lukas' treatment and recovery
REASON FOR COMING FOR TREATMENT: Lukas had been on medication and received regular physiotherapy since his injury in 2005, but had not seen any significant improvement. As a result, his parents decided to bring him to China for stem cell treatment in October 2006. Lukas saw several great improvements after his first round of treatment (as detailed below), and so his parents decided to bring him for a second series of injections in April 2007.
TREATMENT: Oct. 2006: Umbilical Cord Stem Cell and Nerve Growth Factor Injections with Rehabilitation Therapy, Apr. 2007: Umbilical Cord Stem Cell and Nerve Growth Factor Injections with Rehabilitation Therapy
START OF TREATMENT: First treatment: October 9, 2006 Second treatment: April 19, 2007
BEFORE THE TREATMENT: Lukas sustained a severe brain injury in January 2005 when he fell down seven steps on a staircase with his nanny. His brain mass was reduced by 40%, and a fluid sac developed that covered around 35% of his brain. He was in a coma for seven days, and after he came to he had forgotten how to do many of the things he could do before. He had poor trunk strength, and could not stand or sit still without assistance. He could not eat solids. He was also on medication for acid reflux, bowel movements, sleeping problems and irritability. Although he could recognize people that were important to him, such as family members and his doctors, he had problems with objects. He would not make eye contact with those around him, and was generally unresponsive to the world around him.
AFTER THE FIRST TREATMENT: Lukas’ trunk strength improved after treatment, and he was able to sit on his own for long periods of time. He was able to eat solid foods, and his appetite increased. His cognitive skills increased significantly. He was far better at processing visual information, and as a result was much more responsive to the world around him. He could interact with people and objects and was much more playful. Most significantly, a scan taken five months after his return to the United States revealed that the fluid sac that covered his brain had significantly decreased in size. According to his neurosurgeon, it had resolved by 85%. His medications were stopped, and he graduated from all his doctors at home, who were amazed with his progress.
AFTER THE SECOND TREATMENT: Lukas’ muscle strength continued to improve. He could pull himself to a sitting position from a lying position. He was now able to stand on his own for up to two minutes, and it is hoped that he will be able to sit and walk normally in the future. He started speaking more, and was generally calmer and happier than before. The fluid sac covering his brain was now 95% resolved. At the most recent visit to see his neurologist, Lukas was told that he will walk independently and that his gross motor skills can recover greatly.
Stem cell use in animals
Horses
Stem cell treatment has begun on horses, or mainly to treat injuries to the tendons, ligaments, and joints of sport horses or racehorses. Fat is harvested from the tail head and processed, and an animal may receive treatment within three days after the sample is taken. Injuries that may be treated include Degenerative Joint Disease, soft-tissue injuries, Osteochondrosis, fractures, and sub-chonral bone cysts. Currently, research is also being performed on stem cell application in laminitis and COPD.
Dogs
There is currently research being performed on the usefulness of stem cells (mesoangioblasts) in canine muscular dystrophy. This work, which has been successfully translated from mice to dogs could provide a means of treating muscular dystrophy in humans.
Controversy
Main article: Stem cell controversy
There is wide spread controversy over the use of embryonic stem cells. This controversy is over the technique used to create new embryonic stem cell lines, which often requires the destruction of the blastocyst.
Many groups oppose the use of human embryonic stem cells in research based on moral or religious objections. Others point to the success already being achieved with stem cell therapy that does not result in the destruction of a developing human being, such as the use of cord blood cells to treat spinal cord injury paralysis or recent research in turning skin fibroblasts into embryonic stem cell-like cells, and argue that research should be aimed in those avenues with a proven safety and efficacy.
Potential treatments
Brain damage
Stroke and traumatic brain injury lead to cell death characterized by a loss of neurons and oligodendrocytes within the brain. Healthy adult brains contain neural stem cells that divide, and act to maintain stem cells numbers or become progenitor cells. In healthy adult animals, progenitor cells migrate within the brain and function primarily to maintain neuron populations for olfaction (the sense of smell). Interestingly, in pregnancy and after injury this system appears to be regulated by growth factors and can increase the rate at which new brain matter is formed. In the case of brain injury, although the reparative process appears to initiate, substantial recovery is rarely observed in adults suggesting a lack of robustness. Recently, results from research conducted in rats subjected to stroke suggested that administration of drugs to increase the stem cell division rate and direct the survival and differentiation of newly formed cells could be successful. In the study referenced below, biological drugs were administered after stroke to activate two key steps in the reparative process. Findings from this study seem to support a new strategy for the treatment of stroke using a simple elegant approach aimed at directing recovery from stroke by potentially protecting and/or regenerating new tissue. The authors found that, within weeks, recovery of brain structure is accompanied by recovery of lost limb function suggesting the potential for development of a new class of stroke therapy or brain injury therapy in humans.
Cancer
Research injecting neural (adult) stem cells into the brains of dogs can be very successful in treating cancerous tumors. With traditional techniques brain cancer is almost impossible to treat because it spreads so rapidly. Researchers at the Harvard Medical School caused intracranial tumours in rodents. Then, they injected human neural stem cells. Within days the cells had migrated into the cancerous area and produced cytosine deaminase, an enzyme that converts a non-toxic pro-drug into a chemotheraputic agent. As a result, the injected substance was able to reduce tumor mass by 80 percent. The stem cells neither differentiated nor turned tumorigenic.
Spinal cord injury
A team of Korean researchers reported on November 25, 2004, that they had transplanted multipotent adult stem cells from umbilical cord blood to a patient suffering from a spinal cord injury and she can now walk on her own, without difficulty. The patient had not been able stand up for the last 19 years. The team was co-headed by researchers at Chosun University, Seoul National University and the Seoul Cord Blood Bank (SCB). For the unprecedented clinical test, the scientists isolated adult stem cells from umbilical cord blood and then injected them into the damaged part of the spinal cord.
The Korean researchers have followed up on their original work. The original treatment was conducted in November 2004. On April 18, 2005, the researchers announced that they will be conducting a second treatment on the woman.[6] The researchers have followed up with a case study write-up on their work. It is located in the journal Cytotherapy.[7]
According to the October 7, 2005 issue of The Week, University of California researchers injected human embryonic stem cells into paralyzed mice, which resulted in the mice regaining the ability to move and walk four months later. The researchers discovered upon dissecting the mice that the stem cells regenerated not only the neurons, but also the cells of the myelin sheath, a layer of cells which insulates neural impulses and speeds them up, facilitating communication with the brain (damage to which is often the cause of neurological injury in humans).
In January 2005, researchers at the University of Wisconsin-Madison differentiated human blastocyst stem cells into neural stem cells, then into the beginnings of motor neurons, and finally into spinal motor neuron cells, the cell type that, in the human body, transmits messages from the brain to the spinal cord. The newly generated motor neurons exhibited electrical activity, the signature action of neurons. Lead researcher Su-Chun Zhang described the process as "you need to teach the blastocyst stem cells to change step by step, where each step has different conditions and a strict window of time."
Transforming blastocyst stem cells into motor neurons had eluded researchers for decades. The next step will be to test if the newly generated neurons can communicate with other cells when transplanted into a living animal; the first test will be in chicken embryos. Su-Chun said their trial-and-error study helped them learn how motor neuron cells, which are key to the nervous system, develop in the first place. The new cells could be used to treat diseases like Lou Gehrig's disease, muscular dystrophy, and spinal cord injuries.
Heart damage
Several clinical trials targeting heart disease have shown that adult stem cell therapy is safe. However, none of these trials have proven efficacy. Adult stem cell therapy for heart disease is commercially available. Patients such as the late Jeannine Lewis, who died less than one year after treatment, [9] and the late Hawaiian crooner Don Ho, who died within 15 months of treatment, [10] have traveled to Thailand to receive stem cell therapy for their heart disease.
Using the patient's own bone marrow derived stem cells, Dr. Amit Patel at the University of Pittsburgh, McGowan Institute of Regenerative Medicine has shown a dramatic increase in ejection fraction for patients with congestive heart failure. He has worked with many other countries such as Argentina, Uruguay, Ecuador, Greece, Japan, and Thailand where he has taught minimally invasive techniques for the treatment of non-ischemic (idiopathic) and ischemic heart failure.
A Brazilian stem cell bank, has performed sample manipulation in more than 30 cell therapy procedures in cardiac patients.
Haematopoiesis (blood cell formation)
In December 2004, a team of researchers led by Dr. Luc Douay at the University of Paris developed a method to produce large numbers of red blood cells. The Nature Biotechnology paper, entitled Ex vivo generation of fully mature human red blood cells, describes the process: precursor red blood cells, called hematopoietic stem cells, are grown together with stromal cells, creating an environment that mimics the conditions of bone marrow, the natural site of red blood cell growth. Erythropoietin, a growth factor, is added, coaxing the stem cells to complete terminal differentiation into red blood cells.
Further research into this technique will have potential benefits to gene therapy, blood transfusion, and topical medicine.
Baldness
Hair follicles also contain stem cells, and some researchers predict research on these follicle stem cells may lead to successes in treating baldness through "hair multiplication", also known as "hair cloning", as early as 2007. This treatment is expected to work through taking stem cells from existing follicles, multiplying them in cultures, and implanting the new follicles into the scalp. Later treatments may be able to simply signal follicle stem cells to give off chemical signals to nearby follicle cells which have shrunk during the aging process, which in turn respond to these signals by regenerating and once again making healthy hair. Hair Cloning Nears Reality as Baldness Cure (WebMD November 2004)
Missing teeth
In 2004, scientists at King's College London discovered a way to cultivate a complete tooth in mice and were able to grow them stand-alone in the laboratory. Researchers are confident that this technology can be used to grow live teeth in human patients.
In theory, stem cells taken from the patient could be coaxed in the lab into turning into a tooth bud which, when implanted in the gums, will give rise to a new tooth, which would be expected to take two months to grow. It will fuse with the jawbone and release chemicals that encourage nerves and blood vessels to connect with it. The process is similar to what happens when humans grow their original adult teeth.
It's estimated that it may take until 2009 before the technology is widely available to the general public, but the genetic research scientist behind the technique, Professor Paul Sharpe of King's College, estimates the method could be ready to test on patients by 2007.[13] His startup company, Odontis, fully expects to offer tooth replacement therapy by the end of the decade.
In 2005, Cryopraxis a stem cell bank in Brazil, collected baby tooth stem cells and harvested different types of differentiated cell types including neurons. This technology may one day make baby tooth a good source of stem cells.
In the next three years, Paul Sharpe hopes to identify more-accessible stem cells that may be able to form not only teeth, but also--and more importantly--roots.[14]
Deafness
There has been success in regrowing cochlea hair cells with the use of stem cells.[15]
Blindness and vision impairment
Since 2003, researchers have successfully transplanted retinal stem cells into damaged eyes to restore vision. Using embryonic stem cells, scientists are able to grow a thin sheet of totipotent stem cells in the laboratory. When these sheets are transplanted over the damaged retina, the stem cells stimulate renewed repair, eventually restoring vision.[16] The latest such development was in June 2005, when researchers at the Queen Victoria Hospital of Sussex, England were able to restore the sight of forty patients using the same technique. The group, led by Dr. Sheraz Daya, was able to successfully use adult stem cells obtained from the patient, a relative, or even a cadaver. Further rounds of trials are ongoing.[17]
In April 2005, doctors in the UK transplanted corneal stem cells from an organ donor to the cornea of Deborah Catlyn, a woman who was blinded in one eye when an acid was thrown in her eye at a nightclub. The cornea, which is the transparent window of the eye, is a particularly suitable site for transplants. In fact, the first successful human transplant was carried out in 1905 on a cornea by Dr. Eduard Zirm. The recipient was Alois Gloger, a labourer who had been blinded in an accident. The cornea has the remarkable property that it does not contain any blood vessels, making it relatively easy to transplant. The majority of corneal transplants carried out today are due to a degenerative disease called keratoconus which causes vision imapairment and has no known cure even after corneal transplant. It is hoped that stem cell research will one day provide a cure to such debilitating corneal disorders.
As more research yields increasingly precise techniques, stem cell transplantation to restore vision may become viable on a large scale. The success rate of the procedure is currently from 20 to 70 percent,[18] and further stem cell research is required.
ALS (Lou Gehrig's Disease)
In the April 4, 2001 edition of JAMA (Vol. 285, 1691-1693),[19] Drs. Gearhart and Kerr of Johns Hopkins University used stem cells to cure rats of an ALS-like disease. The rats were injected with a virus to kill the spinal cord motor nerves related to leg movement. Dr. Gearhart and Dr. Kerr then injected the spinal cords of the rats with stem cells. These migrated to the sites of injury where they were able to regenerate the dead nerve cells restoring the rats which were once again able to walk.
Current treatments
For over 30 years, bone marrow and more recently umbilical cord blood stem cells have been used to treat cancer patients with conditions such as leukemia and lymphoma. During chemotherapy, most growing cells are killed by the cytotoxic agents. These agents not only kill the leukemia or neoplastic cells, but also those which release the stem cells from the bone marrow. It is this unfortunate side effect of the chemotherapy that the Stem Cell Transplant attempts to reverse; by introducing a Donor's healthy Stem Cells the damaged or destroyed Blood Producing Cells of the patient are replaced. In all current Stem Cell treatments obtaining Stem Cells from a matched Donor is preferable to using the patients own. If (always as a last resort and usually because no matched Donor can be found) it is deemed necessary for the patients own stem cells to be used and the patient has not stored their own collection of stem cells (umbilical cord blood), bone marrow samples must therefore be removed before chemotherapy, and are re-injected afterwards.
Stem cell treatments
Medical researchers believe that stem cell therapy has the potential to radically change the treatment of human disease. A number of adult stem cell therapies already exist, particularly bone marrow transplants that are used to treat leukemia.[25] In the future, medical researchers anticipate being able to use technologies derived from stem cell research to treat a wider variety of diseases including cancer, parkinson's disease, spinal cord injuries, and muscle damage, amongst a number of other impairments and conditions.[26][27] However, there still exists a great deal of social and scientific uncertainty surrounding stem cell research, which could possibly be overcome through public debate and future research.
Stem cells, however, are already used extensively in research, and some scientists do not see cell therapy as the first goal of the research, but see the investigation of stem cells as a goal worthy in itself
Controversy surrounding stem cell research.
There exists a widespread controversy over stem cell research that emanates from the techniques used in the creation and usage of stem cells. Human embryonic stem cell research is particularly controversial because, with the present state of technology, starting a stem cell line requires the destruction of a human embryo and/or therapeutic cloning. However, recently, it has been shown in principle that embryonic stem cell lines can be generated using a single-cell biopsy similar to that used in preimplantation genetic diagnosis that may allow stem cell creation without embryonic destruction.
Opponents of the research argue that embryonic stem cell technologies are a slippery slope to reproductive cloning and can fundamentally devalue human life. Those in the pro-life movement argue that a human embryo is a human life and is therefore entitled to protection.
Contrarily, supporters of embryonic stem cell research argue that such research should be pursued because the resultant treatments could have significant medical potential. It is also noted that excess embryos created for in vitro fertilisation could be donated with consent and used for the research.
The ensuing debate has prompted authorities around the world to seek regulatory frameworks and highlighted the fact that stem cell research represents a social and ethical challenge.
To ensure self-renewal, stem cells undergo two types of cell division (see Stem cell division and differentiation diagram). Symmetric division gives rise to two identical daughter cells both endowed with stem cell properties. Asymmetric division, on the other hand, produces only one stem cell and a progenitor cell with limited self-renewal potential.
Progenitors can go through several rounds of cell division before terminally differentiating into a mature cell. It is possible that the molecular distinction between symmetric and asymmetric divisions lies in differential segregation of cell membrane proteins (such as receptors) between the daughter cells.[21] An alternative theory is that stem cells remain undifferentiated due to environmental cues in their particular niche. Stem cells differentiate when they leave that niche or no longer receive those signals.
Studies in Drosophila germarium have identified the signals dpp and adherins junctions that prevent germarium stem cells from differentiating[22][23]. The signals that lead to reprogramming of cells to an embryonic-like state are also being investigated. These signal pathways include several transcription factors including the oncogene c-Myc. Initial studies indicate that transformation of mice cells with a combination of these anti-differentiation signals can reverse differentiation and may allow adult cells to become pluripotent.[24] However, the need to transform these cells with an oncogene may prevent the use of this approach in therapy.
Adult stem cell
The term Adult stem cell refers to any cell which is found in a developed organism that has two properties: the ability to divide and create another cell like itself and also divide and create a cell more differentiated than itself. Also known as somatic (from Greek Σωματικóς, of the body) stem cells, they can be found in children, as well as adults[13]. Pluripotent adult stem cells are rare and generally small in number but can be found in a number of tissues including umbilical cord blood.[14] Most adult stem cells are lineage restricted (multipotent) and are generally referred to by their tissue origin (mesenchymal stem cell, adipose-derived stem cell, endothelial stem cell, etc.)[15][16]
A great deal of adult stem cell research has focused on clarifying their capacity to divide or self-renew indefinitely and their differentiation potential.[17] In mice, pluripotent stem cells can be directly generated from adult fibroblast cultures.[18]
While embryonic stem cell potential remains untested, adult stem cell treatments have been used for many years to successfully treat leukemia and related bone/blood cancers through bone marrow transplants.[19] The use of adult stem cells in research and therapy is not as controversial as embryonic stem cells, because the production of adult stem cells does not require the destruction of an embryo. Consequently, more US government funding is being provided for adult stem cell research[20].
Embryonic stem cells.
Embryonic stem cell lines (ES cell lines) are cultures of cells derived from the epiblast tissue of the inner cell mass (ICM) of a blastocyst or earlier morula stage embryos [6]. A blastocyst is an early stage embryo - approximately 4 to 5 days old in humans and consisting of 50-150 cells. ES cells are pluripotent, and give rise during development to all derivatives of the three primary germ layers: ectoderm, endoderm and mesoderm. In other words, they can develop into each of the more than 200 cell types of the adult body when given sufficient and necessary stimulation for a specific cell type. They do not contribute to the extra-embryonic membranes or the placenta. Nearly all research to date has taken place using mouse embryonic stem cells (mES) or human embryonic stem cells (hES). Both have the essential stem cell characteristics, yet they require very different environments in order to maintain an undifferentiated state. Mouse ES cells are grown on a layer of gelatin and require the presence of Leukemia Inhibitory Factor (LIF).[7]
Human ES cells are grown on a feeder layer of mouse embryonic fibroblasts (MEF's) and require the presence of basic Fibroblast Growth Factor (bFGF or FGF-2).[8] Without optimal culture conditions or genetic manipulation[9] embryonic stem cells will rapidly differentiate. A human embryonic stem cell is also defined by the presence of several transcription factors and cell surface proteins. The transcription factors Oct-4, Nanog, and Sox2 form the core regulatory network which ensures the suppression of genes that lead to differentiation and the maintenance of pluripotency.[10] The cell surface proteins most commonly used to identify hES cells are the glycolipids SSEA3 and SSEA4 and the keratan sulfate antigens Tra-1-60 and Tra-1-81.
The molecular definition of a stem cell includes many more proteins and continues to be a topic of research.[11] After 20 years of research, there are no approved treatments or human trials using embryonic stem cells. Their tendency to produce tumors and malignant carcinomas, cause transplant rejection, and form the wrong kinds of cells are just a few of the hurdles that embryonic stem cell researchers still face.[12] Many nations currently have moratoria on either ES cell research or the production of new ES cell lines. Because of their combined abilities of unlimited expansion and pluripotency, embryonic stem cells remain a theoretically potential source for regenerative medicine and tissue replacement after injury or disease.
Pluripotent, embryonic stem cells originate as inner mass cells with in a blastocyst. The stem cells can become any tissue in the body, excluding a placenta. Only the morula's cells are totipotent, able to become all tissues and a placentaStem cell properties Defining properties
The rigorous definition of a stem cell requires that it possesses two properties:
* Self-renewal - the ability to go through numerous cycles of cell division while maintaining the undifferentiated state.
* Unlimited potency - the capacity to differentiate into any mature cell type. In a strict sense, this requires stem cells to be either totipotent or pluripotent, although some multipotent and/or unipotent progenitor cells are sometimes referred to as stem cells.
These properties can be illustrated in vitro, using methods such as clonogenic assays, where the progeny of single cell is characterized.[4][5] However, in vitro culture conditions can alter the behavior of cells, making it unclear whether the cells will behave in a similar manner in vivo. Considerable debate exists whether some proposed adult cell populations are truly stem cells.
Potency definitions
Pluripotent, embryonic stem cells originate as inner mass cells with in a blastocyst. The stem cells can become any tissue in the body, excluding a placenta. Only the morula's cells are totipotent, able to become all tissues and a placenta.
Pluripotent, embryonic stem cells originate as inner mass cells with in a blastocyst. The stem cells can become any tissue in the body, excluding a placenta. Only the morula's cells are totipotent, able to become all tissues and a placenta.
Potency specifies the differentiation potential (the potential to differentiate into different cell types) of the stem cell.
* Totipotent stem cells are produced from the fusion of an egg and sperm cell. Cells produced by the first few divisions of the fertilized egg are also totipotent. These cells can differentiate into embryonic and extraembryonic cell types.
* Pluripotent stem cells are the descendants of totipotent cells and can differentiate into cells derived from any of the three germ layers.
* Multipotent stem cells can produce only cells of a closely related family of cells (e.g. hematopoietic stem cells differentiate into red blood cells, white blood cells, platelets, etc.).
* Unipotent cells can produce only one cell type, but have the property of self-renewal which distinguishes them from non-stem cells.
Embryonic stem cells
Main article: Embryonic stem cell
Embryonic stem cell lines (ES cell lines) are cultures of cells derived from the epiblast tissue of the inner cell mass (ICM) of a blastocyst or earlier morula stage embryos [6]. A blastocyst is an early stage embryo - approximately 4 to 5 days old in humans and consisting of 50-150 cells. ES cells are pluripotent, and give rise during development to all derivatives of the three primary germ layers: ectoderm, endoderm and mesoderm. In other words, they can develop into each of the more than 200 cell types of the adult body when given sufficient and necessary stimulation for a specific cell type. They do not contribute to the extra-embryonic membranes or the placenta.
Nearly all research to date has taken place using mouse embryonic stem cells (mES) or human embryonic stem cells (hES). Both have the essential stem cell characteristics, yet they require very different environments in order to maintain an undifferentiated state. Mouse ES cells are grown on a layer of gelatin and require the presence of Leukemia Inhibitory Factor (LIF).[7] Human ES cells are grown on a feeder layer of mouse embryonic fibroblasts (MEF's) and require the presence of basic Fibroblast Growth Factor (bFGF or FGF-2).[8] Without optimal culture conditions or genetic manipulation[9] embryonic stem cells will rapidly differentiate.
A human embryonic stem cell is also defined by the presence of several transcription factors and cell surface proteins. The transcription factors Oct-4, Nanog, and Sox2 form the core regulatory network which ensures the suppression of genes that lead to differentiation and the maintenance of pluripotency.[10] The cell surface proteins most commonly used to identify hES cells are the glycolipids SSEA3 and SSEA4 and the keratan sulfate antigens Tra-1-60 and Tra-1-81. The molecular definition of a stem cell includes many more proteins and continues to be a topic of research.[11]
After 20 years of research, there are no approved treatments or human trials using embryonic stem cells. Their tendency to produce tumors and malignant carcinomas, cause transplant rejection, and form the wrong kinds of cells are just a few of the hurdles that embryonic stem cell researchers still face.[12] Many nations currently have moratoria on either ES cell research or the production of new ES cell lines. Because of their combined abilities of unlimited expansion and pluripotency, embryonic stem cells remain a theoretically potential source for regenerative medicine and tissue replacement after injury or disease.
What is StemCell ?
Stem cells are primal cells found in all multi-cellular organisms. They retain the ability to renew themselves through mitotic cell division and can differentiate into a diverse range of specialized cell types. Research in the human stem cell field grew out of findings by Canadian scientists Ernest A. McCulloch and James E. Till in the 1960s.[1][2]
Mouse embryonic stem cells with fluorescent marker.
The three broad categories of mammalian stem cells are: embryonic stem cells, derived from blastocysts, adult stem cells, which are found in adult tissues, and cord blood stem cells, which are found in the umbilical cord. In a developing embryo, stem cells can differentiate into all of the specialized embryonic tissues. In adult organisms, stem cells and progenitor cells act as a repair system for the body, replenishing 
As stem cells can be grown and transformed into specialized cells with characteristics consistent with cells of various tissues such as muscles or nerves through cell culture, their use in medical therapies has been proposed. In particular, embryonic cell lines, autologous embryonic stem cells generated through therapeutic cloning, and highly plastic adult stem cells from the umbilical cord blood or bone marrow are touted as promising candidates
Human Embryonic Stem cell colony on mouse embryonic fibroblast feeder layer.
