We’re only a week away from the 2010 Winter Olympics opening in Vancouver, and the return of the games brings with it the return of crazy stories about how far world-class athletes will go to get even the tiniest edge, legal or illegal. In the journal Science this week, researchers led by geneticist Theodore Friedmann take the opportunity to warn about gene doping, the next looming crisis in cheating at high-stakes athletics.
Genetic doping isn’t new to the headlines—the International Olympic Committee banned it in 2003. But its prevalence is growing, especially since improving testing is starting to weed out more standard forms of cheating like steroids and EPO, a hormone that boosts red blood cell production. Three years ago, German track coach Thomas Springstein was busted after unsuccessfully trying to score Repoxygen, an experimental gene therapy drug that boosts red blood cell production, for his runners. At the Olympics in Beijing, an unidentified Chinese doctor offered stem cell injections to a German journalist posing as a swim coach [Wired.com].
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The genomes of lung and skin cancer have been decoded by scientists at the UK-based Wellcome Trust Sanger Institute near Cambridge, which is the first time an entire cancer gene map has been created.
The scientists say they have pinpointed specific DNA errors that may cause tumors in these two cancers, both of which have direct known causes—smoking for lung cancer and sun exposure for skin cancer. Researchers predict these maps will offer patients a personalized treatment option that ranges from earlier detection to the types of medication used to treat cancer. The genetic maps will also allow cancer researchers to study cells with defective DNA and produce more powerful drugs to fight the errors, according to the the study’s scientists [CNN]. News reports are heralding the new research as revolutionary, however it will be years, perhaps decades, before the full implications of the work are understood.
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A gene therapy treatment intended to reverse muscle weakness appears to restore muscle mass in monkeys, raising hopes that doctors may soon be able to treat this condition in humans with degenerative diseases like multiple sclerosis and muscular dystrophy. Scientists injected a gene into the monkeys’ thighs that causes cells to produce human follistatin, which interferes with another compound called myostatin. Myostatin breaks down muscle, so in theory adding follistatin should encourage muscles to grow [Reuters].
And grow they did. Within three months the monkeys’ thigh muscle mass increased, and the effect lasted for 15 months, according to the research published in the journal Science Translational Medicine. (Not quite the same effect as the whippet turned hugely muscular by a natural genetic defect.) The relatively long-lasting effect is promising for researchers looking to treat lifelong conditions such as multiple sclerosis and muscular dystrophy. The researchers say the treatment was safe and that no other organs were affected.
But there could be a downside to this promising work–some experts are asking whether this therapeutic technique could be used by unscrupulous athletes looking to tweak their genetics and to build stronger muscles. The drugs companies Amgen and Wyeth have already begun testing myostatin inhibitors in humans and such studies have already prompted fears about the potential for myostatin inhibitors to be abused by athletes hoping to gain the competitive edge. If gene therapy can achieve similar outcomes in humans, such modifications will be even harder to detect [New Scientist]. The World Anti-Doping Authority has banned gene doping in athletic competitions for obvious reasons, even though there’s no evidence that any athletes are tinkering with their genes.
Of course there wouldn’t be: If some jock were gene doping, there would be no way to detect it.
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Image: Wikimedia Commons / Muhammad Mahdi Karim
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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Emphysema and cystic fibrosis patients who need new lungs are faced with a life-threatening problem: more than 80 percent of donated lungs can’t be used—they’re inflamed and barely functional [Scientific American]. Transplanted lungs also fail at a much higher rate than other transplanted organs, as they’re more likely to be rejected by the recipient’s body. But a new procedure that makes use of gene therapy may soon double or triple the supply of undamaged donated lungs, and may also improve their function once transplanted.
In both pre- and post-transplant lungs, the problem is inflammation caused by insufficient amounts of an immune molecule called IL-10. Donated lungs are immediately chilled on ice, which destroys any IL-10 that may remain in the lungs, allowing substantial damage to occur before the organ can be implanted. And a lack of the molecule after transplantation increases the likelihood that inflammation will damage the organ and induce rejection [Los Angeles Times].
To get around these problems, the researchers first built a domed chamber where pig lungs were kept at body temperature with a steady flow of oxygen and nutrients moving through them. That arrangement alone prevented substantial damage to the lungs. Next, in the gene therapy stage, the researchers used a harmless virus to bring a gene that produces IL-10 into the lung cells.
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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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For two squirrel monkeys nicknamed Dalton and Sam, life has gotten a lot more colorful. Researchers used gene therapy to correct the color blindness of the two adult monkeys, giving them the ability to distinguish between red and green for the first time. The fascinating accomplishment suggests that scientists may someday be able to cure other kinds of blindness in humans. And because the treated monkeys were “middle aged”, it challenges the assumption that gene therapies cannot work in adults because their brain connections are too set in their ways to change beneficially [New Scientist].
The field of gene therapy, in which a malfunctioning gene in a patient’s body is replaced with a functional one, fell into disarray one decade ago following the death of an 18-year-old in a clinical trial. But since then scientists have regrouped, using animal studies to probe the technique’s safety. Last year, researchers progressed to the point of safety trials in humans for the treatment of one rare eye condition called Leber congenital amaurosis, and were able to dramatically improve the patients’ sight. Those results were stunning, but they were also achieved in children, whose still-growing brains can rewire themselves on the fly in response to new sources of visual stimuli [Wired.com].
In the new study, published in Nature, the researchers used a type of squirrel monkey in which the males lack a visual pigment called L-opsin. Its absence renders the monkeys color-blind, unable to distinguish reds and green. Most of the females, on the other hand, see in full color. So the scientists got to wondering: what would happen if they gave a boy squirrel monkey the same opsin that girls have [Scientific American]. They used a harmless virus to ferry in the gene that makes opsin, injecting the virus behind the monkeys’ retinas.
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In a remarkable announcement, German researchers have declared that they “functionally cured” a patient of AIDS, eradicating all traces of the virus from his body. The feat was accomplished with a bone marrow transplant from a donor who had a genetic resistance to the virus, and researchers say that 20 months later they can find no trace of the virus in the patient’s blood, bone marrow, or organ tissue.
But the accomplishment shouldn’t be taken as a sign that a cure for the 33 million people living with AIDS is around the corner, researchers are hasty to add. Professor Rodolf Tauber from the [German] clinic said: “This is an interesting case for research. But to promise to millions of people infected with HIV that there is hope of a cure would not be right” [BBC News]. Reasons for this caution include the small number of potential donors with the HIV-resistant mutation, and the difficulty and expense of bone marrow transplants.
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In a promising result for gene therapy, researchers have dramatically improved the vision of several patients with a rare, inherited eye condition called Leber congenital amaurosis. The early study was intended to simply test the safety of the treatment, but the patients displayed such significant improvement that researchers decided to publicize the results.
Gene therapy works on a simple principle – to replace a malfunctioning gene, and restore function to a part of the body affected by a genetic disorder. In practice, however, it has proved very difficult to find ways to introduce the new gene copies in the correct tissues, and experiments in animals have had mixed results [BBC News].
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