Researchers may have taken a step towards curing the rare, inherited brain disease made famous by the movie Lorenzo’s Oil–and also towards ushering a new era of gene therapy. To help two young boys suffering from the disease, researchers tried an experimental treatment using a deactivated version of the HIV virus. The virus delivered working copies of a gene to stem cells from the patients’ bone marrows. The HIV virus, stripped of genetic material that makes it toxic, integrates permanently into the DNA of cells it enters, scientists said. That means the modified gene remains in the blood-forming stem cells for the life of the patient [Bloomberg].
Adrenoleukodystrophy, or ALD, is a progressive disease characterized by the gradual destruction of the myelin sheaths that insulate neurons and nerves, allowing electrical signals to be transmitted through them. The disease is caused by a genetic defect, which prevents cells in the bone marrow from producing a crucial protein necessary for the formation of the myelin sheaths. Typically, children with ALD are given bone marrow transplants to provide them with healthy blood-forming stem cells, but in the two cases described in the study, no matching donors could be found.
In the experimental treatment, described in a paper published in Science, researchers took blood stem cells from the patients’ bone marrow and used the new vector system to genetically alter them by inserting a working copy of the … gene. The modified cells were then put back into the patients [Reuters].
(more…)
The South Korean stem cell scientist who falsified cloning data was convicted today of embezzlement and illegally buying human eggs. The Seoul Central District Court sentenced Hwang Woo-suk to two years in prison for embezzling research funds and illegally buying human eggs. However, it suspended the penalty, allowing him to stay free if he breaks no laws for three years [Washington Post]. The judge stated Hwang has shown remorse and said that despite his fraudulent research the scientist has made other genuine advancements in cloning.
In May 2005, Hwang published a paper in the journal Science, saying his team had extracted material from cloned human embryos that identically matched the DNA of 11 patients. It was claimed such a technique could be the key to providing personalized cures for diseases such as cancer, Alzheimer’s and Parkinson’s [BBC News]. The paper garnered worldwide attention, along with heightened suspicion, because cloning embryonic stem cells was thought to be impossible due to the complexities of human cells. Proving the critics right, an investigation later concluded that the data were intentionally fabricated. Hwang later confessed to obtaining eggs for the research from his female colleagues, a clear violation of research ethics guidelines. However, he maintained that he did not fake his research, and is still working on animal cloning at a local institute.
Related Content:
80beats: Obama’s Guidelines for Stem Cell Research Dodge Controversial Bullets
80beats: Is It Ethical to Pay Women to Donate Eggs for Medical Research?
80beats: Disgraced South Korean Cloning Scientist May Face Jail Time
Image: iStockphoto
A new study may have hit upon another way to improve stem cells‘ ability to help repair damaged tissue. While stem cells can rapidly grow into any kind of new tissue, they aren’t always able to encourage new blood vessels to grow so that the tissue stays alive. But in a new study, published in the Proceedings of the National Academy of Sciences, scientists describe a way around the problem. The researchers used nanoparticles to ferry a key gene into the stem cells, which caused the cells to recruit new blood vessels, thus fueling tissue growth.
The nanoparticles carried a gene (VEGF) that is known to stimulate new blood vessel growth. When the modified cells were injected into mice whose hind limbs had been injured, the tissue that regrew to repair the damage had three times the blood vessel density of similar tissue in mice given unmodified cells. Four weeks later, only 20 per cent of the mice given modified cells had lost limbs, compared with 60 per cent in mice that received unmodified cells [New Scientist].
(more…)
This year, the most prestigious medical awards in the United States have been given to two stem cell researchers, three cancer researchers, and one New York City mayor. Each year, the three prestigious Lasker Awards are given to those who have made great progress in combatting human disease, and they come with a prize of $250,000 in each category. They are sometimes called “America’s Nobels,” in part because 76 Lasker laureates have gone on to receive the Nobel Prize [USA Today].
The basic medical research prize went to John Gurdon and Shinya Yamanaka; although their breakthroughs were separated by 50 years, both researchers’ work led to the current technique of turning ordinary skin cells into multipurpose stem cells. Lasker Foundation president Maria Freire explains that Gurdon’s work showed that the nucleus of every cell retains a latent ability to become any other cell type and Yamanaka showed how that capacity can be unleashed…. “These two pieces of research allow us to understand different aspects of stem cells,” she said. “I think it could lead to personalized replacement therapy to fix cells or damaged tissue” [Bloomberg].
(more…)
The movie Fight Club may have been on the right track when it suggested that the fat left over from liposuction procedures was too valuable to throw away–although the idea of making soap from forsaken flab is too gross to catch on. Instead, researchers have found a way to turn fat cells into stem cells, and say the process is much more efficient than the standard technique for stem cell production, which uses human skin cells.
Reprogramming human skin cells remains woefully inefficient; typically, it takes about a month for 1 in 10,000 fibroblast skin cells to give rise to induced pluripotent stem (iPS) cells. Such iPS cells can, like embryonic stem cells, develop into any cell type. So researchers have been on the lookout for tissue types that can more speedily and easily be turned pluripotent [Nature News].
(more…)
Using a bit of biotech wizardry that is becoming increasingly mundane, researchers took skin cells from patients with type 1 diabetes, and turned them first into induced pluripotent stem cells (iPS cells), the rough equivalent to the embryonic stem cells that can develop into any kind of tissue. Then researchers directed the cells to develop into insulin-producing beta cells, the type of cells that are destroyed by the immune system in type 1 diabetes.
Stem cell expert Meri Firpo notes that this technology could one day be used to create pancreatic beta cells for transplant from a person’s own skin cells. That way, there would be no need for immunosuppressive medications. However, because the current technique uses genetic manipulation to change the cell, Firpo said long-term safety issues would have to be addressed. Mouse cells that have been similarly manipulated have developed benign tumors, she said. So, using such cells for transplant is definitely not “a near-term thing,” she stressed [HealthDay News].
(more…)
A week-and-a-half after the first-ever human clinical embryonic stem cell trial was put on hold, Geron Corp. announced why: microscopic cysts that arose in laboratory animals but did not spread to other locations in the animals’ bodies.
In January, the FDA granted the company permission to begin using its stem cell treatment on patients with spinal cord injuries–but then the trial was delayed before the first patient could be enrolled. Although cysts developed occasionally during previous animal trials, they occurred more frequently in the more recent experiment. Geron was quick to point out, however, that the cysts were small and did not appear to be harmful in any way. In fact, the statement pointed out, cysts are not uncommon in victims of spinal cord injury, developing in the spinal cord scar tissue in up to 50% of patients [The Scientist]. In addition, the cysts did not develop into teratomas, a type of tumor that develops from pluripotent stem cells.
Geron said the company is working with the FDA to investigate the issue, and company officials are confident that the trial will soon be back on track. The FDA offered no comment regarding Geron’s announcement, saying they “neither confirm nor comment on clinical holds” [The Scientist].
Related Content:
80beats: FDA Approves the First Clinical Trials Using Embryonic Stem Cells
80beats: GE Plans to Use Human Embryonic Stem Cells as Lab Rats
80beats: Adult Mouse Gets a New Tooth, Grown From Embryonic Cells
Image: iStockPhoto
In a discovery that could be good news for denture users, scientists have grown teeth in adult mice using cells taken from a mouse embryo, according to a study published in Proceedings of the National Academy of Sciences. The method could pave the way towards the regeneration not just of teeth, but also human organs like livers and kidneys.
Scientists took tissue known as “tooth germ” from a mouse embryo and separated out two types of cells, which they recombined into a new bioengineered tooth germ. That tissue was then implanted into tooth sockets in the mouths of laboratory mice. After 37 days each clump of cells, which originally measured 500 micrometers, or 0.02 inches, had grown into a tooth visibly sprouting from the jawbones of the mice. The researchers also tracked gene expression in the engineered tooth “germ” with a fluorescent protein. This revealed that genes that were normally activated in tooth development were also active during growth of the engineered replacement [BBC News]. The implantation of the tooth “germ” was made possible by a method developed by the same team of scientists in 2007, which allowed them to grow immature teeth inside of the stomachs of embryonic mice.
(more…)
Injecting a certain protein into mice and rats stimulated their heart cells to multiply after a heart attack, improving cardiac function. The experiment’s results point to a possible method to regenerate damaged human heart tissue, according to a study published in the journal Cell.
The adult heart is remarkably static. Although research this year revealed that a tiny number of new heart muscle cells are created in adulthood, that cellular regeneration tapers off throughout life, so heart damage inflicted during a heart attack does not heal naturally. But scientists found that injecting a growth factor called neuregulin1 (NRG1) into mice and rats stimulated the animals’ heart cells to divide. After 12 weeks of daily injections, the animals’ hearts showed less hypertrophy, or enlargement, and improved function. For instance, the hearts had about a 10 percent increase in ejection fraction–the fraction of blood pumped out of the left ventricle with each beat. The treatment “didn’t make the damage go away completely, … but it did make the heart work significantly better” [Technology Review], says lead researcher Bernhard Kühn.
(more…)
From reprogrammed skin cells, scientists have made live mice.
The accomplishment is the latest step forward in the exciting new field of reprogrammed cells, which may offer an alternative to embryonic stem cells…. [It's] the most definitive evidence yet that the technique could help sidestep many of the explosive ethical issues engulfing the controversial field [Washington Post]. Two new studies describe the process, and one team of researchers reports producing 27 live mice. While there were abnormalities and unusual deaths with some of the first generation of mice, [the] team produced enough normal mice this way to create hundreds of second and third generation mice [AP].
It was only three years ago that Japanese stem cell researchers found a way to reprogram ordinary skin cells to behave like embryonic stem cells, which are thought to hold vast potential for medical research because they can develop into any kind of body tissue–from heart cells to toenail cells. But researchers didn’t know if the reprogrammed adult cells, known as induced pluripotent stem cells or iPS cells, were capable of differentiating into every type of tissue, the way embryonic stem cells do.
(more…)
To obtain a steady supply of unfertilized human eggs for medical research, New York’s Empire State Stem Cell Board recently authorized paying women to donate their eggs. The decision has set off a new round of discussion about whether paying for eggs is ethical. The board agreed that women can receive up to $10,000 for donating eggs, a painful and sometimes risky process…. Proponents say compensating women for their eggs is necessary for research, and point out that women who give their eggs for fertility purposes are already paid. Others worry that the practice will commodify the human body and lead to the exploitation of women in financial need [The New York Times].
At the annual meeting of the International Society for Stem Cell Research this week, British researcher Alison Murdoch described a less controversial “egg sharing” program that has met with success. Women struggling to conceive can obtain IVF at a discounted rate, in exchange for donating some of their eggs for research…. In 2008, Murdoch’s team had 191 enquiries from interested women and ended up obtaining 199 eggs from 32 couples. “We are getting donors and we are getting eggs,” says Murdoch. The team is using the eggs in experiments into “therapeutic cloning”, which could ultimately produce stem cells matched to individual patients [New Scientist].
(more…)
British researcher Karim Nayernia says he has produced human sperm from embryonic stem cells for the first time, but his claims have been met with some skepticism. Embryonic stem cells can develop into any kind of cell in the body, but researchers have struggled for years to produce reproductive cells from stem cells. The task is particularly difficult because it requires a complex form of cell division called meiosis, which reduces the number of chromosomes per cell by half [Nature News]. In the new study, published in the journal Stem Cells and Development, Nayernia says his team used a special cocktail of growth factors to transform stem cells into sperm.
But male fertility expert Allan Pacey says the lab’s creations are too abnormal to be called sperm. “I am unconvinced from the data presented in this paper that the cells produced by Professor Nayernia’s group from embryonic stem cells can be accurately called ’spermatazoa.” … Pacey said in a statement that the sperm created by Nayernia did not have the specific shape, movement and function of real sperm [AP].
(more…)
Scientists have identified the “master” stem cell that gives rise to the three types of heart cells, possibly opening the door for new methods of pharmaceutical research and heart therapies, such as growing a patch to repair cardiac tissue damaged by heart disease, according to a study published in Nature.
The research illuminates a crucial facet of how heart tissue develops and shows why past studies to repair heart tissue with stem cells had poor results: the cells used were not the heart tissue progenitors that lead author Kenneth Chien and his team identified. The researchers then purified the cells, cloned them and tracked their journey from single stem cell to the three major lineages of heart cells — smooth muscle, cardiomyocyte [or striated] muscle and endothelial cells [U.S. News and World Report], which line the inside of the heart. For years, scientists have studied the development of the heart in animals like the zebra fish, but this finding will allow researchers to closely examine the genesis of human cardiac tissue in unprecedented detail.
(more…)
Although ethical debates about the use of embryonic stem cells continue to rage, stem cell technology is beginning to make its way into the medical marketplace. Yesterday, General Electric division GE Healthcare announced that it’s teaming up with the biotechnology company Geron in a venture that will use embryonic stem cells to develop products that could give drug developers an early warning of whether new medicines are toxic [Reuters].
The agreement marks the first time that a company of GE’s stature and size has announced a business venture involving the controversial field of embryonic stem cells. That could reflect a more tolerant climate for the technology in the wake of the Obama administration’s recent relaxation of restrictions on embryonic stem-cell research [The Wall Street Journal]. Supporters of embryonic stem cell research say the work will lead to a host of treatments for cancer and other diseases, while opponents believe that the destruction of any human embryo is unacceptable.
(more…)
The question of how salamanders regenerate their legs when amputated is an ancient one that dates back to the days of Aristotle. Now scientists have come one step closer to solving the mystery. Contrary to what researchers previously believed, when a salamander’s legs are removed the cells near the amputation site revert to adult stem cells, but do not become pluripotent, or capable of developing into any body part. That explains why a salamander who loses a tail doesn’t regrow a leg in its place.
In the study, published in Nature, scientists explain that when a salamander’s limb is amputated, the muscle, bone, and skin cells at the amputation site change into a clump of adult stem cells called a blastema. Before this experiment, researchers had hypothesized that these undifferentiated blastema cells — which all look identical — are pluripotent and thus able to form many different cells types. But it was not clear how the original cells from adult tissue were reprogrammed, or how the blastema cells went on to form the correct tissue types [Nature News].
(more…)
