Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Human embryonic stem cells may promise medical advances

12.02.2004


New research – published by Science Magazine within the Science Express Web site and released today at the 2004 AAAS Annual Meeting -- may be a first step toward methods for treating diabetes, osteoarthritis, Parkinson’s and other diseases, by producing replacement cells unlikely to trigger immune-system rejection.



Transplantation medicine based on stem cells remains a distant hope for now, Science editors cautioned. But, the Science study describes intriguing early results:

For the first time, researchers have reported the development of versatile "pluripotent" human embryonic stem cells, potentially capable of becoming any cell in the body, from a cloned human blastocyst. The stem cells were harvested from a blastocyst produced by transferring the nucleus of a non-reproductive ("somatic") cell, containing a woman’s genetic blueprint, into a nucleus-free egg from the same donor.


Following this transfer, factors within the host egg’s exterior, or cytoplasm, reprogrammed its new nuclear contents by activating versatile embryonic genes, while silencing the more limited adult somatic cell genes. Researchers were then able to collect embryonic stem cells from the resulting cell mass inside the cloned blastocysts.

In theory: "Because these cells carry the nuclear genome of the individual, after differentiation they could be expected to be transplanted without immune rejection for treatment of degenerative disorders," reported Woo Suk Hwang of Seoul National University in Korea. "Our approach opens the door for the use of these specially developed cells in transplantation medicine."

Embryonic stem cells have previously been produced with cells from mice using the same method, called "somatic cell nuclear transfer." But, achieving this trick with human cells posed unique challenges, said Donald Kennedy, Science’s Editor-in-Chief.

The researchers attribute their apparent success to the use of extremely fresh donor eggs, stringent timing protocols, and a special method for gently extruding rather than suctioning the DNA-spindle complex from eggs. Suctioning the DNA may damage spindles, possibly causing chromosomal defects called aneuploidy, they noted.

Hwang and colleagues developed the stem cell line, SCNT-hES-1, after collecting 242 eggs from 16 unpaid volunteers who had signed informed-consent agreements. From these eggs, scientists then cultured 30 blastocysts to obtain 20 suitable inner cell masses. By tweaking the amount of time that elapsed between the transfer of the nucleus and the activation of the newly transplanted genetic material, the team was able to optimize their results: A two-hour delay seemed to work best, so that 20 percent of all reconstructed eggs formed blastocysts. From the inner cell mass of these blastocysts, a single human embryonic stem cell line was obtained.

The resulting stem cells differentiated into all three of the main tissue types that appear at the beginning stages of development, researchers reported. When transplanted into mice, the stem cells differentiated into still more specific cell types, offering further proof of pluripotency.

Interestingly, the research team harvested eggs as well as somatic cells from the same donors: Nuclear material from the somatic cell was transferred into the nucleus-free or enucleated egg of the same woman. This unusual experimental design may be more effective than person-to-person transfers because it offered greater compatibility between the genetic components that were fused together.

But, were the stem cells truly derived from the transferred nucleus, or were they the result of an accidental "parthenote"--an artificially induced blastocyst resulting from an egg that began to spontaneously divide? To support their claim that the resulting stem cells came from the transplanted nucleus, Hwang’s team completed DNA fingerprinting analysis, and also checked the expression of imprinted genes. The results were consistent with stem cells resulting from transplantation.

Many questions remain, Science’s Donald Kennedy said: "The potential for embryonic stem cells is enormous, but researchers still must overcome significant scientific hurdles," Kennedy remarked. "These results seem promising. But, it’s important to remember that cell and tissue transplantation and gene therapy are still emerging technologies, and it may be years yet before embryonic stem cells can be used in transplantation medicine."

The research also raises policy and ethical questions, Kennedy noted, since blastocyst-derived stem cells for tissue repair or transplantation might exacerbate pressures on egg donors in some regions. The prospect of using cloned human blastocysts to produce new embryonic stem cells lines also is likely to provoke further controversy, he added. "There is widespread consensus among all responsible, mainstream scientists--including the authors of this paper and AAAS, publisher of Science Magazine--that any attempt to clone a human being would be highly dangerous and wrong, and therefore, all reproductive cloning should be banned," Kennedy said. "But, the generation of stem cells by somatic cell nuclear transfer methods involving the same individuals may hold promise for advances in transplantation technology that could help people affected by many devastating conditions."

In addition to Hwang, authors on this Science paper were Young June Ryu, Eul Soon Park, Eu Gene Lee, Hyun Yong Chun, Byeong Chun Lee, Sung Keun Kang, Curie Ahn and Shin Yong Moon, all of Seoul National University; as well as Jong Hyuk Park and Sun Jong Kim of Mizmedi Hospital in Seoul; Ja Min Koo of Gachon Medical School; Jung Hye Hwang of Hanyang University; Ky Young Park of Sunchon National University; and Jose B. Cibelli of Michigan State University.


´´
The American Association for the Advancement of Science (AAAS) is the world’s largest general scientific society, and publisher of the journal, Science (www.sciencemag.org). AAAS was founded in 1848, and reports some 265 affiliated societies and academies of science, serving 10 million individuals. Science has the largest paid circulation of any peer-reviewed general science journal in the world, with an estimated total readership of one million. The non-profit AAAS (www.aaas.org) is open to all and fulfills its mission to "advance science and serve society" through initiatives in science policy; international programs; science education; and more. For the latest research news, log onto EurekAlert!, www.eurekalert.org, the premier science-news Web site, a service of AAAS.

MEDIA NOTE: A newsbriefing on this research will take place at 11:00 a.m. Pacific Time, Thursday, 12 February, during the AAAS Annual Meeting in Seattle, in the Eliza Amphitheater, Grand Hyatt. Further, these and other speakers will take part in a symposium titled, "Stem Cell Science in the Service of Society," at 2:30 p.m. Monday, 16 February, Sheraton Hotel, Second Floor, Grand Ballroom C. Press registration is in the AAAS Press Center in Leonesa I of the Grand Hyatt Hotel.

AAAS is the world’s largest general scientific society, dedicated to "Advancing science · Serving society."

Ginger Pinholster | EurekAlert!
Further information:
http://www.aaas.org/

More articles from Health and Medicine:

nachricht New discoveries predict ability to forecast dementia from single molecule
12.12.2018 | UT Southwestern Medical Center

nachricht Pain: Perception and motor impulses arise in the brain independently of one another
12.12.2018 | Technische Universität München

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Lethal combination: Drug cocktail turns off the juice to cancer cells

A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.

The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...

Im Focus: New Foldable Drone Flies through Narrow Holes in Rescue Missions

A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.

Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...

Im Focus: Topological material switched off and on for the first time

Key advance for future topological transistors

Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...

Im Focus: Researchers develop method to transfer entire 2D circuits to any smooth surface

What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.

Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices...

Im Focus: Three components on one chip

Scientists at the University of Stuttgart and the Karlsruhe Institute of Technology (KIT) succeed in important further development on the way to quantum Computers.

Quantum computers one day should be able to solve certain computing problems much faster than a classical computer. One of the most promising approaches is...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

 
Latest News

New discoveries predict ability to forecast dementia from single molecule

12.12.2018 | Health and Medicine

CCNY-Yale researchers make shape shifting cell breakthrough

12.12.2018 | Physics and Astronomy

Pain: Perception and motor impulses arise in the brain independently of one another

12.12.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>