When a person’s cornea is burned it’s not necessarily the splashed chemicals or hot liquids that causes blindness, but the eye’s recovery. Scar tissue, formed from cells in the white part of the eye, can cover the cornea in a cloudy haze. But researchers have found that cells drawn from another part of the body can correct the problem.
A paper published yesterday in the New England Journal of Medicine brings news of a regenerative stem cell treatment that has had striking success: It restored sight to 82 of 117 eyes with burnt corneas, and worked partially on 14 others. The treatment also seems to have a long-lasting impact; in one patient, the beneficial effect has lasted for ten years and counting.
The treatment offers hope to those who received little benefit from existing therapies–such as artificial cornea replacements, which can also be overpowered and clouded by white-colored cells, or stem cell or cornea transplants from cadavers, which patients can reject.
“[The patients] were incredibly happy. Some said it was a miracle,” said one of the study leaders, Graziella Pellegrini of the University of Modena’s Center for Regenerative Medicine in Italy. “It was not a miracle. It was simply a technique.” [AP]
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The International Society for Stem Cell Research has had enough. When the organization of stem cell scientists met last week in San Francisco, its leaders promised to get serious about unregulated stem cell treatments.
First, society president Irving Weissman declared his intention to “smoke out the charlatans,” New Scientist reported. The ISSCR is investigating its members who provide advice to clinics that offer experimental stem cell treatments (no such treatments have yet received FDA approval).
At a press briefing on 17 June, he revealed that these members are being told to explain their connections with such clinics. Expulsion from the society was a possibility for members who continue to associate themselves with unproven “therapies”, added Sean Morrison of the University of Michigan in Ann Arbor, a member of the ISSCR board of directors [New Scientist].
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A woman with kidney disease has died after receiving an experimental stem cell treatment at a private clinic in Thailand, and a postmortem examination of her kidneys revealed that the treatment was almost certainly responsible for her death. Last week we reported that Costa Rica’s health ministry had closed a stem cell clinic that catered to foreigners, which sparked lively debates around the Internet about whether patients should be able to willingly take on risks associated with experimental treatments. This new case offers a sobering reminder of what can happen when patients travel abroad looking for a miracle cure.
The woman suffered from lupus nephritis, a disease in which the immune system attacks the kidneys. When medications no longer controlled her disease, she went to a still-unnamed clinic in Bangkok where doctors said they could treat her disease using stem cells drawn from her own bone marrow. There was some medical rationale for this:
Bona-fide trials in European clinics about six years ago showed that some people with similar kidney disease benefited if stem cells from their own bone marrow were injected into their blood. The body’s immune system was first deliberately destroyed with powerful immunosuppressive drugs, then the reinjected stem cells helped to stop the attacks on the kidney by rebuilding and rebalancing the immune system. [New Scientist]
However, the Thai clinic didn’t inject the stem cells into the patient’s blood stream, instead they injected them directly into her kidneys. That means the stem cells did nothing to stop the immune system’s attack on the organs–and they instead produced never-before-seen side effects.
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When it comes to research on HIV and AIDS treatments, it can be hard to know when to celebrate a small advance–everyone wants to see progress, but so many experimental avenues that seemed promising have turned out to be dead ends. Still, a new study that tried a sophisticated form of gene therapy as an HIV treatment seems cause for cautious optimism. If it bears out under further testing, the technique could lead to a one-shot, long-lasting treatment that could replace the punishing regimen of daily medications.
Treating HIV currently comes down to managing the viral load with a mixture antiretroviral drugs. Researcher John Rossi and his colleagues tried to craft a more direct treatment by genetically modifying the HIV-infected patients’ own blood stem cells and increasing the cells’ ability to fight off the virus. The researchers weren’t able to truly combat the virus in this experiment–the patients’ viral loads remained the same–but their work moved beyond previous attempts in two ways: They successfully modified blood stem cells by giving them anti-HIV genes, and those cells survived for two years in patients.
Earlier clinical studies the group conducted with the same strategy made little headway, but now the researchers have overcome two key obstacles, says Rossi, a molecular geneticist. One is that they managed to stitch the anti-HIV genes into a high percentage of the appropriate stem cells. The other is that the cells lived for a long time. “If we could increase the number of modified cells by 10- or 100-fold, we might be able to stop the virus itself,” says Rossi. [ScienceNow]
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Last month, Costa Rica’s health ministry halted treatments at the country’s largest stem cell clinic, arguing that the treatments are unproven and possibly unsafe.
Though the Obama administration has expanded federal funding of stem cell research and there are ongoing clinical trials, there are currently no FDA-approved stem cell treatments. So some Americans, suffering from conditions ranging from cancer to spinal injuries, have looked elsewhere for experimental stem cell-based remedies, and clinics in countries such as Costa Rica, China, India, and Mexico have grown into stem cell tourist destinations.
Costa Rica’s largest clinic, the Institute of Cellular Medicine in San Jose, was operated by American entrepreneur Neil Riordan; it attracted about 400 patients for these treatments. The clinic used adult stem cells, which Costa Rica’s government had allowed the clinic to take from patients’ fat and bone marrow. The government had not authorized the clinic to use these cells for treatment.
“If (stem cell treatment’s) efficiency and safety has not been proven, we don’t believe it should be used,” said Dr. Ileana Herrera, chief of the ministry’s research council. “As a health ministry, we must always protect the human being.” [Reuters]
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When a person has a heart attack, the heart repairs its damaged muscle by forming scar tissue. As a result, the heart never truly goes back to the way it was. But when a zebrafish has a heart injury, like having a large chunk of it chopped off, it grows a brand new piece to replace it.
Two independent reports published in the journal Nature show that within days of an injury to its heart, the zebrafish has the remarkable ability to regenerate most of the missing cardiac tissue using mature heart cells–not stem cells, as some researchers had suspected.
The findings help explain why human beings can’t regenerate a heart or missing limbs. The reports contradict a previous study (pdf) done by one of the research teams in 2006 that suggested that stem cells, the general all-purpose cells that develop into all the mature and functional cells of the body, were responsible for self-repair.
The finding suggest that doctors have been on the wrong track with recent stem cell-based therapies for heart attack patients. Many heart patients have received injections of stem cells, often ones taken from their own bone marrow. But the beneficial effects have generally been unremarkable [The New York Times].
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When scientists first created induced pluripotent stem cells (iPS cells) three years ago, they were hailed as a game-changing advance for medicine: Scientists hoped the engineered cells could duplicate the talents of embryonic stem cells, which can develop into any kind of cell in the body, while avoiding the destruction of embryos. However, a new study by one of the leading U.S. cell labs suggests that iPS cells, at least right now, have serious problems keeping them from reaching their potential.
Advanced Cell Technologies, the Massachusetts lab led by stem cell guru Robert Lanza, released a study of 25 embryonic lines and eight iPS lines in the journal Stem Cells last week. At first they found that human iPS cells could indeed generate blood vessel, blood precursor and retinal cells with characteristics similar to ones derived from embryonic stem cells, albeit with significantly reduced efficiency [Scientific American]. But the blood and retinal cells showed much higher rates of cell death and premature aging. According to Lanza, “there was a 1,000- to 5,000-fold difference” between the iPS cells’ ability to keep growing and dividing and the true embryonic cells’ ability, he says. “In terms of whether you can use the cells therapeutically or to study disease, that’s the difference between getting the study to work and being dead in the water” [Newsweek].
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Last year DISCOVER asked the question, “Did We Mate With Neanderthals, or Did We Murder Them?” Now, Zach Zorich at Archaeology magazine is asking another big question about our hominid siblings: Should we bring them back?
Thanks to a slew of recent advances, the possibility is getting closer. 80beats reported a year ago that researchers had published the rough draft of the Neanderthal genome. However, that’s likely to contain many errors because it’s so difficult to reconstruct ancient DNA. Within hours of death, cells begin to break down in a process called apoptosis. The dying cells release enzymes that chop up DNA into tiny pieces. In a human cell, this means that the entire three-billion-base-pair genome is reduced to fragments about 50 base-pairs long [Archaeology].
Even if scientists succeed in figuring out the entire Neanderthal genome, they’d be faced with another problem before they could even consider the possibility of cloning one of these ancient hominids: We don’t have any living Neanderthal cells to work with. Thus, researchers will have to figure out how to put DNA into chromosomes, and how to get those chromosomes into the nucleus of a cell. What about altering the DNA inside a living human cell, and tweaking our genetic code to match the Neanderthal’s? This kind of genetic engineering can already be done, but very few changes can be made at one time. To clone a Neanderthal, thousands or possibly millions of changes would have to be made to a human cell’s DNA [Archaeology].
Even if scientists manage to put Neanderthal DNA in a cell nucleus, their problems aren’t over. The next step in creating a baby clone is to move the cell nucleus into the egg of a related species in a technique called nuclear transfer, and then implanting the altered egg in a female who can bear it to term. But in this process, which has been extensively tested on animals, cells often get sick or die, causing fetuses to die in the womb or clones to die young. That’s why the vast majority of scientists oppose using this method on people. Even if nuclear transfer cloning could be perfected in humans or Neanderthals, it would likely require a horrifying period of trial and error [Archaeology].
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Cells just keep surprising us. Researchers have now found that, with a little genetic tweaking, they can transform skin cells into brain cells without having to first reprogram them to act like multipurpose stem cells. This finding, the first of its kind, is in this week’s edition of the journal Nature.
The researchers did their study on mice. They induced the change by inserting only three genes into cultured skin cells. Once those three genes activated, the skin cells converted into fully functioning nerve cells that even formed synapse connections with the other converted nerve cells [Popular Science]. That change took less than a week, a surprisingly rapid rate. Said team member Marius Wernig: “These are fully functional neurons. They can do all the principal things that neurons in the brain do” [AFP].
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President Obama followed through yesterday on his plan to ease restrictions on stem cell use in research funded by taxpayer money. National Institutes of Health leader Francis Collins announced that the organization has approved 13 new lines of embryonic stem cells for research, and will consider 96 more lines for approval.
In March, Obama lifted President Bush’s restrictions on federally-funded research on embryonic stem cells, which limited research to a handful of lines created before August 2001. Obama could not on his own reverse the Congressional ruling that forbids scientists from using taxpayer money to create new stem cell lines from embryos, but the ruling allows researchers to use cell lines created by others in an ethical fashion. The NIH set up a panel to decide which stem cell lines met strict ethical restrictions. The cells, for instance, have to have been made using an embryo donated from leftovers at fertility clinics, and parents must have signed detailed consent forms [Reuters].
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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].
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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].
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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].
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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].
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