It was only a few years ago that scientists figured out how to reprogram adult cells to make them act like multipurpose stem cells, but the next discoveries are coming fast and furious. Researchers had previously transformed human skin cells into so-called induced pluripotent stem (iPS) cells that can grow into any type of tissue; now, a new study reports that the same feat has been accomplished with pig cells. The achievement raises the possibility that genetically engineered pigs could be reared as organ donors, researchers say.
The created iPS cells could be genetically altered, and then cloned to produce pigs with certain traits. By adding or deleting certain genes, for example, researchers could produce pigs whose organs can be transplanted into patients without them being recognised and rejected. Efforts to do such xenotransplants have already been under way for at least a decade, but iPS cells are easier to genetically engineer and grow in the lab than pig embryos, opening up new possibilities for xenotransplantation [New Scientist]. Pigs are considered potential organ donors because their organs are already similar to those of humans in size and function.
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Scientists have taken another step in cellular reprogramming that points the way towards the use of a patient’s own cells to treat genetic diseases. In a proof of concept study, researchers took skin cells from patients with a rare condition, Fanconi anemia, which causes skeletal problems and bone-marrow failure, and raises sufferers’ risk of cancer [Technology Review]. In the skin cells, the researchers fixed the genetic defects that caused the disease, and then reprogrammed the cells to act like stem cells capable of growing into any type of tissue.
The corrected stem cells could be grown into blood precursor cells for therapy. As these would carry a patient’s own DNA, except for the mutation responsible for the illness, they could be transplanted without risk of rejection by the body’s immune system [Times Online]. However, the patched up cells were not used to treat patients in this study, because it isn’t yet clear whether such cells are safe. Comments molecular geneticist Chris Mathew: “In future it may become possible to transfer the corrected stem cells back into the patient, but much work remains to be done before this can be transferred from the lab bench to the bedside” [The Scientist].
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Researchers have found a new way to reprogram human skin cells to act like multipurpose stem cells, and say their safe technique produces stem cells that are ready for medical use. If the researchers are right, clinical trials on the induced pluripotent stem (iPS) cells, which can turn into virtually any cell type and potentially be used to treat disorders ranging from spinal cord injury to diabetes, could start within two years [Nature News].
Many experts say that reprogrammed skin cells have several advantages over embryonic stem cells, for reasons both societal and medical. Using adult cells dodges the ethical controversy involved in taking cells from embryos, and it also raises the possibility that patients’ own cells could be used in their medical treatment, negating the chance that the cells would be rejected by their bodies. But reprogramming cells is still a scientific frontier, and researchers have struggled to find safe ways to accomplish the feat.
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Three patients with severe damage to the corneas of their eyes have achieved dramatic improvements in their vision thanks to contact lenses coated with their own stem cells. While the study was extremely small and the results are quite preliminary, the unequivocal improvement seen in the three patients has given doctors hope that the treatment may work for many patients with damaged corneas. Two of the three patients were legally blind in the treated eye; they can now read big letters on the eye chart. The third could read the top few rows of the chart but is now able to pass the vision test for a driving license [The Australian].
The cornea is the transparent layer that covers the eye – but it can lose transparency, damaging sight. In the most serious cases, people can need cornea grafts or transplants. Corneal disease can be caused by genetic disorders, surgery, burns, infections or chemotherapy. In this study, all three patients had damage to the epithelium – the layer of cells covering the front of the cornea [BBC News].
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The beating of the heart inside an embryo doesn’t just circulate blood through the developing creature, it also triggers the formation of blood stem cells, the cells that give rise to all other forms of blood cells, according to two new studies. The surprising findings show that the physical force of the heartbeat and blood flowing through the aorta cause embryonic stem cells to differentiate–although researchers don’t yet understand quite how this is accomplished.
The findings could eventually have practical applications for people with blood cancers and other diseases that are treated with transplants of bone marrow, the site of blood stem cell production. Scientists can make red and white blood cells easily in the laboratory, but bone marrow patients need blood stem cells to constantly replenish their blood supply. Producing these cells, also called hematopoietic stem cells, is much more difficult…. Only about a third of patients who require bone marrow transplants have matching donors. “Basically we cannot offer optimal therapy to two-thirds of patients” [Science News], says Leonard Zon, coauthor of one of the new studies. If researchers can learn how the body stimulates blood stem cell production, they may be able to duplicate the process in the lab, says Zon.
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The Obama administration’s new guidelines for research using human embryonic stem cells have staked out a compromise position, avoiding some controversial areas while still encouraging a large expansion of federally-funded research. The proposed regulations would allow research on stem cells taken from surplus embryos at fertility clinics, where in vitro fertilization generally creates more embryos than will be implanted, and embryos not used are destroyed or kept frozen. The guidelines would allow couples to donate embryos for research, as long as they are not paid and are fully informed of their options [Washington Post].
However, the guidelines do not sanction the use of embryos created specifically for research purposes, an extra step that officials say does not yet have public or political support. The draft guidelines also forbid funding for lines derived through parthenogenesis, a form of asexual reproduction in which an unfertilized egg is developed into an embryo. The International Stem Cell Corporation, a California company, has reported deriving stem cells from parthenotes [Nature News]. Finally, the guidelines prohibit the use of stem cells from human embryos created by cloning, although no such embryos are known to exist.
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Stem cell transplants may free type I diabetics of the need for insulin injections, according to a small study in which 20 of 23 patients became insulin-free for up to four years. The study, published in the Journal of the American Medical Association, involved injecting people with stem cells made from their bone marrow cells [Reuters]. Twelve of the patients went for an average of 31 months with no insulin injections. Eight other study participants experienced “transient” insulin independence, meaning they had to start taking insulin again at lower levels [U.S. News and World Report].
The treatment was designed for patients newly diagnosed with type 1 diabetes, a condition that usually develops in childhood and occurs when the immune system goes haywire and starts attacking itself, destroying insulin-producing cells in the pancreas needed to control blood sugar [Reuters]. These beta cells are produced in a part of the pancreas called the islets of Langerhans. In the study, the stem cells were first frozen. The patients were next given a large dose of drugs to knock down their immune systems. The stem cells were then thawed and re-injected back into their bloodstream over about 15 minutes [Australian Broadcasting Corporation]. Over the following days, months, and years, researchers measured their patients’ levels of C-peptides, molecules that indicate how well the body is producing insulin. They found that the stem cell transplants resulted in higher C-peptide levels, indicating healthy beta cells.
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A group of researchers has found stem cells in the ovaries of mice that they say can be prodded to become new eggs, which can then be fertilized to produce healthy offspring. The provocative findings challenge one of the most fundamental assumptions in biology: that female mammals, including women, are born with all the eggs they will ever have…. While much more research is needed to confirm and explore the findings, the work raises the tantalizing possibility that it could someday lead to new ways to fight a woman’s biological clock, perhaps by stockpiling her egg-producing cells or by stimulating them to make eggs again [Washington Post].
In the study, published in the journal Nature Cell Biology, researchers wrote that the stem cells were cultured for more than six months and then transplanted into the ovaries of infertile female mice, … adding that eighty percent of these mice went on to produce offspring after natural mating [Reuters].
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Stem cells may one day provide a cure for deafness, if scientists can build on recent experiments in which a British research team grew the very delicate hair cells of the inner ear from fetal stem cells. These inner ear cells are crucial for hearing but are also irreplaceable and extremely frail. The new study marks the first time they’ve been grown in a laboratory.
The use of stem cells is promising because they can become any kind of cell in the body, and could thus not only be used to replace the lost hair cells, but also any damaged nerve cells along which the signals generated by the hair cells are transmitted to the brain [BBC]. The researchers grew the hair cells from cochlear stem cells they’d isolated from fetuses, cells which are only produced from 9 to 11 weeks into a pregnancy. “That’s why deafness is permanent, because we don’t have the stem cells to replace damaged cells in the ear” [New Scientist], says Marcelo Rivolta, lead researcher of the study published in the journal Stem Cells. The stem cells were taken from aborted fetuses, with full consent of the women involved.
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A high-powered consortium in the United Kingdom has declared a push to create synthetic blood from embryonic stem cells over the next decade. “In principle, we could provide an unlimited supply of blood in this way” [BBC News], says researcher Marc Turner. Synthetic blood would be guaranteed to be free of viruses like HIV, and could also prevent shortages at blood banks, emergency rooms, and battlefield operations.
While the American biotech company Advanced Cell Technology (ACT) announced last August that they had developed a technique of creating blood from embryonic stem cells, the new UK effort has more significant institutional backing. The multimillion-pound deal involving NHS [National Health Service] Blood and Transplant, the Scottish National Blood Transfusion Service and the Wellcome Trust, the world’s biggest medical research charity, means Britain will take centre stage in the global race to develop blood made from embryonic stem cells [The Independent].
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Researchers have developed a treatment based on an injection of neural stem cells encased in a biodegradable polymer that replaced the brain tissue in rats that had been damaged by stroke. Led by British neurobiologist Mike Modo, the team was able to show that the hole in the brains of rats caused by a stroke was completely filled with “primitive” new nerve tissue within seven days. This raises the possibility of radically better treatments for a condition that is the leading cause of adult disability in industrialized countries [Technology Review].
Previous stem cell research in rats with stroke damage had seen some success, but was limited by the tendency of the cells, which lack structural support, to migrate into tissue outside the targeted area. For the new study, which will be published in Biomaterials, the researchers used the polymer PLGA to construct tiny balls one-tenth of a millimeter thick, and loaded them with neural stem cells. These were injected into holes in the brain created when the immune system removes dead tissue caused by a stroke. The polymer’s ready-made support structure helped the stem cells to form new brain tissue in the cavity [BBC].
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President Obama will lift restrictions on human embryonic stem cell research today, reversing the policy put into place by George W. Bush eight years ago that strictly limited federal financing of the research. By signing an executive order today, President Obama will fulfill a campaign promise to encourage medical research on embryonic stem cells, which scientists believe hold enormous potential to treat a host of diseases and injuries. Researchers who have struggled to find funding for embryonic stem cell work are rejoicing over the decision. “Hallelujah! This marks the end of a long and repressive chapter in scientific history. It’s the stem cell ‘emancipation proclamation’,” said Dr. Robert Lanza of Advanced Cell Technology in Massachusetts [Reuters].
A science adviser to the president also said that Obama will issue a memorandum to “restore public confidence in the process by which scientific policy is used to guide government action,” by directing his administration to draft guidelines for the use of scientific information and the appointment of outside science advisers [The New York Times]. Science advisers say the president wants to make clear that his political agenda will not trump scientific judgment, in sharp contrast to the previous administration. The decision by President George W. Bush to restrict funding for stem cell research has been seen by critics as part of a pattern of allowing political ideology to influence scientific decisions across an array of issues, including climate change and whether to approve the morning-after pill Plan B for over-the-counter sales [Washington Post].
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The controversy surrounding stem cell research might soon be moot, with new research showing that ordinary skin cells can be transformed into an equivalent of embryonic stem cells, which have been the focus of research because of their ability to become any kind of cell in the human body. This is known as a pluripotent state, and the new research, published in two articles in Nature, marks the first time that scientists have turned skin cells into induced pluripotent stem cells or iPS cells—which look and act like embryonic stem cells—without having to use viruses in the process [Reuters].
Scientists have been able to make stem cells from adult cells for more than a year, but relied on the injection of a virus to trigger the transformation of the cell into the embryonic state. These cells could not be used on patients, however, because of the risk they presented of developing cancer. Now, researchers in Britain and Canada have produced the cells by using strands of genetic material, instead of potentially dangerous genetically engineered viruses, to coax skin cells into a state that appears biologically identical to embryonic stem cells [Washington Post].
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A new study shows that teenage boy developed cancerous tumors because of the stem cell therapy he received years ago for a rare genetic condition. The boy, now 17, suffered from ataxia telangiectasia, or AT, a neurodegenerative disease that interferes with the part of the brain that controls movement and speech. AT patients do not usually live past their teens or 20s, and the Israeli boy, whose identity was not publicly revealed, was taken to Russia for experimental treatment. The first neural stem cells, taken from fetuses, were first injected into his brain and spinal cord when he was nine, and he received further injections at ages 10 and 12.
His condition deteriorated and he was using a wheelchair by age 13, when he also began to complain of headaches. Tests showed two growths, one pushing on his brain stem and the other on his spinal cord. The tumors were removed in 2006 and his health has since remained stable. But scientists at Tel Aviv University who wanted to determine the origin of the cancer have been in the lab ever since, and their findings have just been published in PLoS Medicine. The team found that the tumor could not have arisen from the boy, because he [has two disease-causing versions of the gene] that causes AT, while the DNA from the tumor cells carried only the normal version [The Scientist].
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After years of fiddling with human, mouse, rabbit, and cow cells, researcher Robert Lanza has declared that it’s impossible to create human-animal hybrid embryos, but that human cloning appears to be eminently doable.
Lanza wasn’t trying to create some freakish chimera, nor did he intend to bring forth a squalling baby as the world’s first human clone. But ever since researchers cloned Dolly the sheep in 1996 by transferring the nucleus of one of her cells into the nucleus-free egg of another sheep, scientists, ethicists, politicians, and the public have wondered whether a person could be cloned in the same way [ScienceNOW Daily News]. While human cloning has largely been rejected as unethical, many researchers are excited by the idea of “therapeutic” cloning, in which the same technique could be used to create embryos that would be harvested for medically useful stem cells. Those stem cells would have the same genetic profile as a patient and would thus avoid immune-rejection issues [ScienceNOW Daily News].
Because of the shortage of human egg donors, the hybrids were proposed as a way of creating large numbers of human embryo clones to harvest stem cells in bulk [Telegraph]. Lanza’s stem cell company, Advanced Cell Technology, has spent several years inserting human nuclei into egg cells from mice, rabbits, and cows, but all of the thousands of embryos they created in this way failed to develop. “At first we thought it would just be a matter of tweaking the culture conditions,” says Lanza. But “the problem was far more fundamental” [Nature News].
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