NEWS : TECH (NFPC)

Brain Cells Made from Urine: DNews Nugget

Brain Cells Made from Urine: Scientist have discovered an uncomplicated technique for turning cells discarded in urine into neurons. Other research typically uses embryonic stem cells, which can be coaxed to grow into just about any cell found in the body, including brain cells. But there are certain risks associated with embryonic stem cells, such as the development of tumors after transplant into a body.

Biologist Duanqing Pei and his colleagues at China's Guangzhou Institutes of Biomedicine and Health have shown that kidney epithelial cells in urine can be turned into pluripotent stem cells, which can grow into any cell in the body. The scientists reprogrammed the epithelial cells by inserting new genetic information into the them. Then they allowed the cells to grow. In about twelve days -- about half the time of other procedures -- the pluripotent cells grew into a rosette shape common to neural stem cells. Next, the scientists transplanted the cells into newborn rat brains. Remarkably, the cells did not form tumors and after four weeks had taken on the shape of neurons. via Nature

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Dog Nose Cells Repair Spine: DNews Nugget

Dog Nose Cells Repair Spine: Scientists used nose cells from pet dogs paralyzed in accidents to restore movement to their legs. The clinical trial, which involved 34 pet dogs with spinal cord injuries, is the first to show that using olfactory ensheathing cells could significantly repair damaged spines.

It's been known for more than a decade that these cells support nerve fiber growth. But so far, no one has found a way to effectively use them to treat damaged spinal cords. Professor Robin Franklin, one of the study leaders from Cambridge University, and his colleagues took olfactory ensheathing cells (OECs) from the lining of a group of dogs and injected those cells, with a liquid, into the injury site. Each month, the scientists test the dogs for neurological function. Significant improvement was seen in the dogs injected with OECs, but not those receiving the placebo treatment. The scientists reported their results in the journal Brain.

The researchers cautioned that these are preliminary results and that the new nerve connections that were generated occurred over short distances. That means that the technique might be able to restore a small amount of movement in human patients with spinal cord injuries, but would not likely restore all function.

Yahoo! News

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Vroom! World's Fastest Cells Drag Race

Ladies and gentlemen, start your... Petri dishes.

It may not have been the Indy 500, but a line of fetal mesenchymal bone marrow cells from Singapore recently out-dashed dozens of contenders to take the checkered flag at the World Cell Race. Claiming their title as the world's fastest cells, the microscopic racers zoomed across a Petri dish at the whiplash-inducing speed of 5.2 microns per minute, or 0.000000194 miles per hour.

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Results were announced December 3 at the American Society for Cell Biology's annual meeting in Denver, Colo. Fifty participating labs from around the world used 70 cell lines to not only race, but examine cell movement during the development of embryos, organs and cancer.

Teams shipped the cells frozen to designated laboratories in Boston, London, Heidelberg, Paris, San Francisco and Singapore. Once thawed, the cells were placed in "race tracks" that were 400 microns long (0.015748 inches) and coated with a substance that gave the little guys some tire-like traction. Digital cameras recorded the cells for 24 hours to determine, out of the 200 cells, which one was the fastest to reach the end of the track.

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A line of unaltered breast epithelial cells took second place and third place went to the the same cell type only altered to reflect patterns observed in cancerous cells. Researchers responsible for the winning cells received Nikon digital cameras and World Cell Race medals.

[Via Nature]

Credit: Monya Baker

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Human Skin Cells Turned Into Neurons

Over the past few years, the boiling debate over the ethics of stem cell research has been brought to a slow simmer due to a series of huge advances in cellular reprogramming. The latest of these breakthroughs is the conversion of mature human skin cells into neurons.

A group of scientists led by principal investigator Marius Wernig at Stanford University had already achieved this feat with rodent skin cells in January 2010, but this May they published a paper in Nature announcing the successful conversion using human cells.

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One of the most striking aspects of this achievement is that it bypasses the ‘Induced Pluripotent Stem Cell’ (IPS cell) phase. Human IPS cells were first produced in 2007, heralding a new era of scientific inquiry in which stem cell research is no longer automatically associated with the controversial harvesting of embryonic cells. Although this technique has been refined since then, there are still major obstacles to using IPS cells. One major detriment, for instance, is that some of the proteins that play a role in reprogramming cells can cause tumors.

DNEWS VIDEO: SYNTHETIC LIFE, ENGINEERING TISSUE AND MORE …

The new research announced by Wernig’s team skips the IPS stage completely and instead manipulates four genes in the skin cells, causing a direct conversion to electrically active neurons. However, the team still faces some daunting challenges on the road to achieving highly reliable conversions. The efficiency of the conversion appears to be quite low, with about 2 to 4 percent of the skin cells converting to functioning neurons. Another major obstacle is that almost all the converted cells seem to be responding to only 1 out of the roughly 100 neurotransmitters that are active in humans. Although this puts a significant damper on how much neural disease research can be carried out in the immediate future, it is a very substantial step in the right direction.

Credit: 3d4Medical.com/Corbis

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Are Stem Cells Immortal?

In 1975, biochemist John Cairns published a phenomenal idea: that stem cells retain much of their original DNA strands despite replication. No matter how cancer or aging altered an organism, the original blueprints remained. Cairns called his idea the immortal strand hypothesis.

What's the truth behind this idea? Are stem cells really immortal?

When Cairns was formulating his hypothesis, scientists had already observed that newly formed stem cell chromosomes consisted of an older grandparent template DNA strand and a newly synthesized parent DNA strand. Of these two, the younger DNA strand was more likely to contain replication errors.

Imagine a whisper passed around a room in a parlor game, or a photocopy of a copy and you get a rough idea of what's going on. Only the accumulated changes in DNA don't merely mix up words or obscure typography. They can cause permanent mutations and ultimately lead to cancer.

Cairns theorized that when a stem cell divides, a mechanism sorts all of the chromatids (or twin halves of a replicated chromosome) containing older, more pristine grandparent templates into one daughter cell. The other daughter cell received all of the chromatids containing potentially mutated parent templates.

The inheritance was a bit lopsided, or asymmetrical.

 

WATCH VIDEO: Scientists from the J. Craig Venter Institute have produced a living cell powered by manmade DNA, creating what they call the world's first synthetic cell. Lead researcher Craig Venter talks about what this milestone means.

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Testing Asymmetrical Segregation
The immortal strand hypothesis hinges on this very mechanism of asymmetrical segregation, according to Sean Morrison, director of the University of Michigan's Center for Stem Cell Biology.

"The idea only makes sense if the stem cell is dividing asymmetrically," Morrison says, "One daughter cell is a stem cell, and the other daughter cell differentiates."

In an attempt to prove or disprove the immortal strand hypothesis, various researchers set out to track stem cell replication.

"A bunch of papers have been published offering evidence in support of this immortal strand idea," Morrison says. "But the problem is that many people have not been convinced by the published evidence because in the majority of the papers that have been published, researchers have not had the benefit of rigorous stem cell markers that could really distinguish stem cells from other cells."

As a result, numerous published papers in support of immortal strand hypothesis still left some scientists skeptical. Laboratories such as Morrison's continue to test the immortal strand theory with stem cell markers.

"Our paper was the first that really did a careful job of sorting out the stem cells," Morrison says, "We looked very hard for whether we could see any evidence of asymmetric chromosome segregation either in vivo or in culture, and we absolutely couldn’t see it."

Yet even if the immortal strand hypothesis doesn't fly, Morrison says that it doesn't rule out the possibility that some varieties of stem cells are carrying out asymmetrical reproduction.

In Support of the Immortal Strand Hypothesis
Boston Biomedical Research Institutes' James Sherley, on the other hand, says that a lot of the evidence to support immortal strand hypothesis is already on the table.  

"There are maybe all together now maybe 10 reports of immortal DNA strand co-segregation, three in tissues and the other ones in culture systems," Sherley says. "If you look at the reports that say to the contrary, there are only five."

Sherley believes that the problem with the dissenting papers is that they ignore cells that have properties consistent with immortal DNA asymmetric segregation.

"The reason [some researchers] ignore them is that they make a statistical error," Sherley says. "The [tests for asymmetric segregation] are fairly complicated, and the interpretation is even more complicated. One of the things that we've been trying to do is develop a simpler assay."

So Sherley hopes to develop not only another way of looking at DNA segregation, but also a method that results in fewer difficulties interpreting the data. As for continuing disagreements among researchers about the famous hypothesis, Sherley is hopeful for reconciliation.

"I think it's going to be ironed out in the next five years or so," Sherley says.

Credit: iStockphoto

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Biotech Could Take Rabbits Off Lab Duty

When Ken Aldrich describes the cornea forming in a petri dish at his company's lab, it sounds crazy. But these little ball of cells might actually spare animals from lab testing and be used for transplants in humans.

Aldrich is chairman of International Stem Cell Corporation, a biotech company headquartered in Oceanside, California. ISCO has deftly avoided the ethics debate with its parthenogenetic stem cell technology. Their process uses unfertilized eggs not needed for IVF, with consent. Scientists then use a combination of chemicals, temperature, and oxygen control to prompt cell division, which creates a group of cells called a blastocyst to make a stem cell line. No sperm needed. (The results were published in peer-reviewed Cloning & Stem Cells Journal.)

While growing stem cells in the lab using blastocysts, researchers spotted something in the waste products usually discarded from the petri dish. "One of them saw a translucent ball like a teeny tiny marble that we’d never seen before and had the good sense to put it aside," Aldrich told me over the phone. "It turned out to be a human cornea." At this point I shivered involuntarily.

Cells don't normally assemble themselves in a petri dish, but some are programmed with certain tendencies. Heart cells will beat, for example. Aldrich says they're not sure exactly why the cells formed a ball with layers, but the company's scientists were able to show that their discovery really was a human cornea and even replicate the result.

Many cosmetics, drug, and chemical companies still put their products in live rabbits' eyes for safety testing--a process that's not only awful for the animals but time-consuming and expensive. Aldrich says that with the ISCO corneas, an initial round of testing demonstrated that they have the same permeability as the rabbit eyes. The lab-grown corneas also have the potential to be transplanted into humans one day. Aldrich says that this could make a big difference in countries where it's difficult to get refrigerated donor corneas to patients in time.

Currently the company is repeating a round of validation testing to confirm its permeability results. I can't wait to see what happens. 

Photo: It's an eye! Courtesy Ken Aldrich/ISCO.