Return to Website

Movers & Shakers Forum

Welcome to our forum. Feel free to post a message.

Movers & Shakers Forum
Start a New Topic 
Author
Comment
View Entire Thread
Researchers Create Stem Cells Without Destroying Embryos

Researchers Create Stem Cells Without Destroying Embryos

By GAUTAM NAIK
November 20, 2007 8:55 a.m.


In the quest to treat difficult diseases, researchers have created human embryonic stem cells without destroying embryos or using hard-to-get eggs. The technique may prove to be easier, cheaper, and more ethically appealing than an alternative approach that requires cloning.

Two separate teams of researchers say they have sidestepped the cloning method and reprogrammed mature human cells into a primordial, embryonic-like state. Those cells were then transformed into other tissue types, such as heart cells. The long-term hope is that such freshly-created tissue may, for example, be used to heal a heart-attack patient.

Unlike cloning, "the wonderful thing about this approach is that it's easy. You're going to see lots and lots of labs give it a try," predicts Robert Blelloch, a stem cell biologist at the University of California, San Francisco, who has performed his own reprogramming experiments. He says he read the latest studies but wasn't involved in them.

One set of experiments, published today in the journal Cell, was led by Shinya Yamanaka of Kyoto University. A second paper was published in Science by researchers at the lab of James Thomson of the University of Wisconsin, who created the first human stem-cell line in 1998.

The Science and Cell papers were embargoed for general release until noon, New York time, but an Australian paper broke the embargo.

In both experiments, the scientists inserted several genes into a mature human cell. For reasons that no one can yet fully explain, this essentially reset the molecular clock and turned older, mature cells into embryonic-like cells.

There are several limitations to the current approach. For now, both teams had to use dangerous viruses to effectively transport the genes into the cell, which could have deadly consequences if it was immediately applied to humans. Dr. Yamanaka and others say they are testing other viruses in the hopes of finding a non-harmful one.

And before the reprogramming technique can be applied to human patients, it needs to be tested on large animal models to ensure that it's safe and effective.

Still, the latest results are a big step up from similar breakthroughs in mice, separately reported this summer by Dr. Yamanaka's group and two other research teams in the U.S. The Kyoto team reported that embryonic-like cells developed with the new technique could even help form a new mouse -- a gold-standard test for the viability of the created tissue.

Almost nobody predicted that the same feat could be repeated with human cells quite so quickly.

"We were very surprised because human and mouse embryonic cells are very different," says Dr. Yamanaka, who is also a senior investigator at the Gladstone Institute of Cardiovascular Disease in San Francisco, and is rapidly emerging as the leading scientist in his field. Much of the reprogramming experiments published this summer was sparked by a landmark paper he published in 2006.

Many scientists have believed that stem cells' grand promise would more likely be fulfilled if they created an embryonic clone of a patient, and then harvested that clone for fresh tissue. Heart, nerve or other cells obtained that way would have a singular advantage: They wouldn't trigger an immune response from patient because they'd share the same DNA.

There aren't any sizable ethical concerns or immune-response worries with reprogramming. But to many, the science seems daunting, even implausible.

"You have this extremely strong arrow of time -- and it's is going completely backwards," says Dr. Thomson. His team, including researcher Junying Yu, also used four genes to reprogram the human cell. Two of the genes they used were different from the ones tested by their counterparts in Japan.

Despite the latest breakthroughs, the nuclear transfer approach - which uses a cloning step to get embryonic stem cells - isn't likely to disappear. Just last week, for example, researchers in Oregon created embryonic clones of monkeys, suggesting that the nuclear-transfer method still hold considerable promise.

However, nuclear-transfer is being held back by several problems. It's hard to get human eggs; the technology is expensive and tricky; and funding isn't so readily available. A major scandal has hurt, too. In 2005, a Korean researcher published a study that appeared to show that he had created human-embryonic clones, but the claim turned out to be fraudulent.

So it's not such a surprise that Ian Wilmut, the man who cloned Dolly the sheep a decade ago, recently said he has been persuaded to give up his own cloning experiments, thanks to news of Dr. Yamanaka's successes.

"Any scientist with basic technology in molecular and cell biology can do reprogramming," says Dr. Yamanaka. "If we can overcome the issue [of having to use dangerous viruses to ferry the genes into cell

Neupro Recall

UCB Advises US-Physicians to Down-Titrate Patients on Neupro In View of Out-of-Stock Situation
PharmaLive.com - BRUSSELS, Belgium - March 20, 2008 at 7:00 am CET - UCB announced today that the company will be recalling Neupro® (rotigotine transdermal system) in the United States and certain batches in Europe. The recall decision resulted from ongoing monitoring of marketed product, which revealed a deviation from the approved product specification. As a result, there will be an out-of-stock situation with Neupro® in the United States in late April 2008. In the European Union and most other regions Neupro® supply is sufficient.

"We have informed the FDA and agreed to actions to inform healthcare providers and patients," said Iris Loew-Friedrich, MD, PhD, Chief Medical Officer, UCB. "We advise patients in the US to contact their healthcare provider to begin the down-titration of Neupro® as per the guidelines in the label. It is strongly advised that patients do not discontinue therapy abruptly. I also want to emphasize that the issue is not one of product contamination or toxicity but rather one of possibly reduced clinical performance of some patches."

Down-titration (reduction of the dose) should be gradual and performed under medical supervision. Rapid reduction of therapy for Parkinson's disease has been associated with a symptom complex resembling neuroleptic malignant syndrome or akinetic crises.