Embryo free way to make cells 'safe'

Evidence that it should be possible to take skin cells and safely turn them into embryonic like cells to treat a vast range of diseases is published today.

The work takes doctors one step closer to the day that doctors will not need to clone embryos in order to create an unlimited supply of any of a patient's own cells and tissues for novel treatments and transplants, whether to treat diabetes or Parkinson's disease.

Researchers recently showed that adult human and mouse skin cells could be "reprogrammed" to be capable of generating any type of cell in a manner similar to embryonic stem cells, sidestepping many ethical objections to this work.

Now the pioneer of this method, Prof Shinya Yamanaka of Kyoto University, reports today in the journal Science that his team has moved another step closer to understanding how these "induced pluripotent stem cells" or iPS cells might be reprogrammed without causing tumours when they are transplanted into the body, a crucial step if they are used to study disease or developed for human therapies.

Dr Takashi Aoi and his other colleagues reprogrammed adult mouse liver and stomach lining cells into iPS cells by genetically altering the cell by introducing three new genes with a kind of virus, called a retrovirus.

There have been concerns that the retrovirus could trigger cancer, by introducing the new genes in such a way to cause problems to useful stretches of DNA, for instance genes that suppress tumour growth.

The team was able to confirm in iPS cells made from adult cells that the virus did not insert genes this way. Mice implanted with the rejuvenated cells remained tumour-free six months after receiving the new cells.

But he tells the Telegraph that practical uses of the reprogrammed cells are still years away.

"In order to apply this technology to clinics, we still have to study the safety of iPS cells in bigger animals such as monkeys," he says. "It will take years to do this."

"It is very encouraging that the method does not lead to preferential insertion of the retroviruses into tumour suppressor genes," comments Dr Robin Lovell-Badge of the National Institute for Medical Research, London.

"However, even if rare, this may happen occasionally, so some caution is still needed. The insertions could also effect genes required for the iPS cells to form the specific cell types that might be required for cell-based therapies.

"So it would still be better if the reprogramming method could avoid the use of these viruses. This is one reason why it is still desirable to pursue other methods of reprogramming, such as so-called "therapeutic cloning". Once we understand how reprogramming works we can devise the ideal way to achieve it safely."

Prof Yamanka's work is a remarkable advance that prompted Sir Ian Wilmut, who led the team that cloned Dolly the sheep, to tell The Daily Telegraph that he would adopt the new method rather than the nuclear transfer method that his team used to create Dolly.

The Japanese work has now been confirmed in other laboratories. A few days ago, UCLA stem cell scientists led by Kathrin Plath and William Lowry used genetic alteration to turn back the clock on human skin cells and create cells that are nearly identical to human embryonic stem cells, iPS cells.

"Our reprogrammed human skin cells were virtually indistinguishable from human embryonic stem cells," says Dr Plath. "We are very excited about the potential implications."

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Jumper's Tricked-Out Teleportation: Hollywood Sci-Fi vs. Reality

Director Doug Liman (inset) did some DIY jump-cut teleportation in his office before digitally zapping Hayden Christensen around the world. (Images courtesy of 20th Century Fox)

Teleportation has long been the object of real-world desire—not to mention sci-fi speculation, from Star Trek to The Twilight Zone to Heroes. Though scientists have actually had some success in the lab, the fact remains that you can’t spontaneously disappear and travel wherever you want. And that, according to director Doug Liman, is the sole fallacy of physics he accepted when filming Jumper, featuring Star Wars vet Hayden Christensen as a kid with a genetic anomaly that allows him to skip through wormholes across the world. “What if somebody had this power?” Liman asks. “That’s the only leap of faith that I took in the movie. Everything else is grounded in the real physics of our world.”

The Director’s Take

After guiding Matt Damon through amnesia in The Bourne Identity and now getting set for a modern-day, DIY recreation of the Apollo missions for his next film, Liman is happy to call himself a science geek—honest portrayals are the key to his films, even since playing it indie cool during his Swingers years. “I wanted to keep the physics everywhere else as honest as possible,” he tells PM. “Other films that have had super powers say, ‘Well, now that there’s a super power—we’re going to ignore every law of physics on the planet.’ That’s why you end up with Spider-Man existing in a [place] that feels nothing like our world, [where] everybody else can do extraordinary things. Gravity doesn’t even seem to apply because there [are] people zipping around on anti-gravity boards. Those things feel like cartoons to me.”

So Liman did his own prep work on the circumstances around a jump, experimenting with its look and its scientific premise at the same time. “[I] basically started with someone sitting in my office and pointing a video camera at them and being like, ‘Okay, I’m going to teleport them out of the chair’—starting with the most rudimentary, which is you pause the camera and they leave the frame and you start the camera again,” he says. Then came the physics: With a character’s weight shifting off the chair, the air vacuum and surrounding environment in a teleportation scene would be more crucial than the jump itself. “The jump is extraordinarily unimpressive,” Liman admits, “because I felt anything that powerful and that violent would happen in a split second, which means you basically can’t see it.” Indeed, we get no wormholes, no slo-mo—just some post-teleport scars, from frost on a windshield to oil floating on the surface of water.

Liman was also preoccupied with what would happen when ordinary nonjumpers were exposed to the wormholes left behind by the likes of Christensen and Samuel L. Jackson. “If you opened a temporary wormhole between two places, before it closed up, that would be something extraordinarily violent and dangerous,” he says. “One of the rules of science is that everything that we do in this world, there’s a price to be paid—nothing comes for free. And one of the prices to be paid is that, if you jump, you leave this wormhole behind. That wormhole is dangerous for people who might stumble across it before it evaporates.”

The wormholes that bad guy Samuel L. Jackson flies through in Jumper are nothing compared to the unstable ones physicists have found in the real world. "If you try to fly through them," says MIT professor Max Tegmark (inset), "the whole thing collapses into a black hole." (Still courtesy of 20th Century Fox)

The Physics Reality

Dr. Max Tegmark, a physics professor at MIT who recently participated in a teleportation panel discussion with Liman, says he was impressed by the filmmaker’s ambition to get the physics right. “It was very good to see a movie director trying to make things as realistic as he could, at least within the confines of the script,” Tegmark says of Jumper, which is based on a Steven Gould sci-fi novel. Some of Liman’s leaps of scientific intuition, such as environmental disruption based on air pockets left by the jumper, “make perfect sense,” Tegmark says.

And make no mistake: While Liman and his team just assumed that humans can’t jump in real life, teleportation does exist—just not the way it’s portrayed on screen. The physical particles don’t move, but their quantum information does—essentially cloning them at a distance. So electrons and ions have “teleported” before, and last year scientists beamed data from photons almost 90 miles between two of the Canary Islands. But even teleporting one particle at a time—say, an electron—is not a simple process. It requires three electrons—the one you want to teleport, and a pair of entangled electrons that split. One electron learns information about the electron to be teleported while the third receives that information at the destination, creating a perfect clone down to the electron’s quantum state; the information about the original is then destroyed. “You don’t want to teleport yourself unless you’re really confident that it’s going to work,” Tegmark says.

Physicists, meanwhile, aren’t sure that traversable wormholes are even possible. “I think Liman had in mind that there was supposed to be some kind of wormhole through space-time, and that’s how it was supposed to work,” Tegmark says. “The ones we know of in physics don’t just appear out of nowhere, and they’re very unstable. If you try to fly through them, the whole thing collapses into a black hole. It’s still an open problem in physics—whether all wormholes are unstable or whether by putting dark energy in them you can make them stable, and whether or not traversable wormholes are actually possible.” Regardless, he says, stabilized, traversable wormholes aren’t coming anytime soon.

One real world physics conundrum the script leaves out, Tegmark says, is energy conservation. “As you convert yourself into pure energy, you correspond to many, many megatons of energy,” he explains. “If you unleash that in an uncontrolled way, it would look like a giant nuclear bomb—and you didn’t see anything like that in the movie.”

One thing’s for certain: It will be a long time before we’re teleporting humans, “not because it’s impossible, but because there’s not much incentive to do it,” says Tegmark, who pinpoints information transfer as the most apt use for teleportation. “If you send an encrypted message over the Internet from the White House to the Pentagon, you’re always worried that someone’s going to eavesdrop on you,” he says. “But if you teleport your information through fiberoptic wires, we know from the basic principles of quantum mechanics that no one can eavesdrop on you. No one can get to that message without the message self-destructing.”

Regardless of whether or not Liman has his science right, Tegmark applauds the film. “I think it’s great that Hollywood makes you think about what’s possible in physics and what’s not,” he says. “In my experience as a scientist, it’s not always about finding the right answer but finding the right question.”

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Green Basics: Carbon Footprint

In addition to metrics like ecological footprint, each of us (and each of the products and services we use and consume every day) has a carbon footprint; it's a way to measure the relative impact of our actions -- as individuals, as businesses, communities and countries, as we eat, work, travel, play, etc. -- in terms of the contribution made to global climate change. Measured in carbon emissions (usually in pounds, tons or kilograms), it's become an increasingly useful and popular tool to help contextualize global warming in our daily routines and lives.

A carbon footprint is the total amount of carbon dioxide (CO2) and other greenhouse gases emitted over the full life cycle of a product or service, and everything has one, from the computer you used to find this article to the next meal you eat (and the one after that, and after that, and so on...) to the shoe that will leave a physical footprint on the ground the next time you walk outside. But that's only part of the story.

First of all, carbon footprints can be calculated in one of two ways: using a Life Cycle Assessment (LCA) method (more accurate and specific), or it can be restricted to the immediately attributable emissions from energy use of fossil fuels (more general). To use your car's carbon footprint as an example: the first method would take into account all carbon emissions required to build the car (including all the metal, plastic, glass and other materials), drive the car and dispose of the car; the second would account only for the fossil fuels that resulted from building, driving and disposing of it.

Further, there's more than one way to run the numbers, depending on how they're going to be used. Top-down calculations, like those done in the world map above and the US state map below, that calculate per capita carbon footprints, take total emissions from a country (or other high-level group, organization, etc.) and divide these emissions among the residents or otherwise applicable group. Bottom-up calculations, like with your car's carbon emissions from the example above, sum attributable carbon emissions from individual actions.
Okay, so everything has a carbon footprint, and each can be measured a couple different ways, but it's not just a matter of carbon dioxide, though that is the most common of greenhouse gases (GHGs) other than water vapor; other GHGs include (but aren't limited to) methane, ozone, nitrous oxide, sulfur hexafluoride, hydrofluorocarbons, perfluorocarbons and chlorofluorocarbons (see the IPCC list of greenhouse gases for a more thorough list). Given this, still, most carbon footprint calculations include all applicable gases, as they all contribute to the greenhouse effect and our persistently warming globe.

Though a fairly complex calculation, with many variables that are different for each person, carbon footprint calculations generally include energy used to power our homes and transport, including travel by car, airplane, rail and other public transport, as well as all the consumables we use on a regular (and irregular) basis; many of the individual factors above can be calculated separately (e.g. an individual carbon footprint for your home, travel, food, etc.). Once you understand what goes in to your carbon footprint, and, probably more importantly, what your carbon footprint is, you can start reducing it; indeed, for as many ways as there are to create a carbon footprint, there are ways to reduce it.

Increasing the efficiency of our energy use, reducing our energy use and changing a few habits (like eating less meat, eating more local food, not traveling by airplane as much) are some of the quick, easy ways to cut back on the size our individual carbon footprints. After increasing efficiency and reducing use, carbon offsets are also an increasingly popular (and increasingly controversial) way to help mitigate our carbon footprints -- see TreeHugger's How to Green Your Carbon Offsets guide for more on that. But the point remains: there are many, many ways to reduce and even eliminate your carbon footprint; most every article you'll read on TreeHugger will be related to carbon footprints and emissions, though some more directly than others.

Moving forward, we expect to see more and more information about the carbon footprints of the things we encounter and use every day; carbon labeling for produce is catching on the UK, and we've seen carbon footprint measurements for everything from cheeseburgers to Christmas, and sushi to Shaq. Want more? Type 'carbon footprint' into our search engine, above, on the right, and go nuts.

Ready to find out what your carbon footprint is? There are a handful of calculators out there; try The Nature Conservancy's Carbon Footprint Calculator and the calculator at ClimateCrisis.net (yep, the site for An Inconvenient Truth) for starters.

Quench your thirst for more green knowledge with our Green Basics column, which appears on TreeHugger on Thursdays.

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