Stories tagged Stem cells

Feb
05
2008

Hetero, homo, and 3-way embryo creation

Embryo - 5 weeks
Embryo - 5 weeksCourtesy Ed Uthman
Lesbian couples could one day have children who share both their genes. Karim Nayernia, Professor of Stem Cell Biology at Newcastle University, has applied for ethical approval from the university to use bone marrow stem cells from women to start experiments to derive female sperm.

“I think, in principle, it will be scientifically possible,” Prof Nayernia told New Scientist.

Babies from two men

Other research is setting the stage for a gay man to donate skin cells that could be used to make eggs, which could then be fertilized by his partner’s sperm. A surrogate's uterus would be needed to bring the baby to term.

In Brazil, a team led by Dr Irina Kerkis of the Butantan Institute in Saõ Paulo claims to have made both sperm and eggs from cultures of male mouse embryonic stem cells in the journal Cloning and Stem Cells.

Babies from a man and two women

A whole class of hereditary diseases, including some forms of epilepsy, result from faulty DNA related to mitochondria. Starting with 10 severely abnormal embryos left over from traditional fertility treatment, researchers removed the nucleus, containing DNA from the mother and father, from the embryo, and implanted it into a donor egg whose DNA had been largely removed. The only genetic information remaining from the donor egg was the tiny bit that controls production of mitochondria. The embryos then began to develop normally, but were destroyed within six days.

"We believe that from this work, and work we have done on other animals that in principle we could develop this technique and offer treatment in the forseeable future that will give families some hope of avoiding passing these diseases to their children." said Patrick Chinnery, a member of the Newcastle team.

If you have an opinion on these types of research, feel free to comment.

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Nov
20
2007

Stem cell research milestone

Cut spinal cords, destroyed brain tissue, or damaged heart muscle can be repaired by injecting stem cells into the damaged area. Embryonic stem (ES) cells are like blank cells that give rise to every type of cell and tissue in the body. Using human embryos or unfertilized human eggs as a source of stem cells raised show-stopping opposition. Now stem cells have been produced from skin.

Human stem cells from skin

Two separate teams of researchers announced on Tuesday they had transformed ordinary skin cells into batches of cells that look and act like embryonic stem cells -- but without using cloning technology and without making embryos.

Both teams call the new cells induced pluripotent stem (iPS) cells and say they look and act like embryonic stem cells.

The research was published online Tuesday by two journals, Cell and Science. The Cell paper is from a team led by Dr. Shinya Yamanaka of Kyoto University; the team published by Science was led by Junying Yu, working in the lab of stem-cell pioneer James Thomson of the University of Wisconsin-Madison.

Thompson said the technique is so simple that "thousands of labs in the United States can do this, basically tomorrow." In contrast, the cloning approach is so complex and expensive that many scientists say it couldn't be used routinely to supply stem cells for therapy.

Learn more

Remember the fraudulent research of South Korean scientist Hwang Woo-suk? A new analysis of Hwang's research indicates that the disgraced scientist actually did reach a long-sought scientific goal. It's just not the one he claimed.

Jun
09
2007

New source of stem cells without destroying embryos.

Stem cells from mouse tails: Photo adapted from Kadath
Stem cells from mouse tails: Photo adapted from Kadath

Stems cells can self-renew or go through numerous cycles of cell division while maintaining their undifferentiated state. Stem cells also have the capacity to differentiate into any mature cell type. These unique properties make stem cells very promising in research toward fixing damaged nerves, diabetes, and Alzheimer's. But research involving stem cells has been limited because obtaining stem cells involved destroying human embryos.

Piece of mouse's tail transformed into living mouse.

Researchers found a way to use skin cells from an adult mouse to create stem cells like that of an embryo.

Four genes, which code for four specific proteins known as transcription factors, are transferred into the cells using retroviruses. The proteins trigger the expression of other genes that lead the cells to become pluripotent, meaning that they could potentially become any of the body's cells. Yamanaka calls them induced pluripotent stem cells (iPS cells). "It's easy. There's no trick, no magic," says Yamanaka. Nature.

Principle proven, but not for humans, yet.

But the iPS cells aren't perfect, and could not be used safely to make genetically matched cells for transplant in, for example, spinal-cord injuries. Yamanaka found that one of the factors seems to contribute to cancer in 20% of his chimaeric mice. He thinks this can be fixed, but the retroviruses used may themselves also cause mutations and cancer.

"This is really dangerous. We would never transplant these into a patient," says Jaenisch.

In his view, research into embryonic stem cells made by cloning remains "absolutely essential". ScienceBlogs.com

"Human embryonic stem cells remain the gold standard for pluripotent cells, and it is a necessity to continue studying embryonic stem cells through traditional means." Jaenisch, MIT.edu/news

Barriers to embryonic research are breaking

After more than two years of legal wrangling, California is free to spend over $3 billion during the next decade on stem cell research. California Institute for Regenerative Medicine (CIRM) is now free to raise some $300 million per year by selling bonds. New Scientist

In the United Sates Congress, the House gave final approval on Thursday to legislation aimed at easing restrictions on federal financing of embryonic stem cell research, but Democratic leaders in both chambers conceded they were short of the votes needed to override a veto threatened by President Bush. Any effort to override a veto would begin in the Senate, where the bill passed April 11 on a 63-45 vote. Even counting the three Senate Democrats who were not present for the vote, passage was one vote shy of the two-thirds majority needed to override a veto. New York Times.

Research paper in Stem Cell journal

Feb
24
2007

Mouse embryonic stem cells stained with a fluorescent green marker.: Image courtesy: Niels Geijsen, Massachusetts General Hospital/National Science Foundation
Mouse embryonic stem cells stained with a fluorescent green marker.: Image courtesy: Niels Geijsen, Massachusetts General Hospital/National Science Foundation
Meri Firpo, a former featured Scientist on the Spot, has been accused by a member of the Minnesota House of Representatives of breaking the law. According to Representative Dan Severson (R-Sauk Rapids) a 1973 state statue on human research appears to make the embryonic research that Dr. Fripo conducts illegal. The accusations came as state lawmakers debated in committee funding for embryonic stem cell research.

According to a recent Star Tribune article, “At the Stem Cell Institute, much of Firpo's work takes place within a locked, windowless 250-square-foot lab where every pen, every vial -- even the lab's share of ventilation -- must be carefully documented to ensure that it isn't paid for with federal dollars. The university is scrupulous about not using any of its state funding as well. With a budget of $250,000 scrounged from private donations, Firpo and others hunt for the information that will eventually, they believe, lead to cures for diabetes and other illnesses.”

Many other states, like Wisconsin, support stem cell research with state funding. Minnesota does not. Governor Tim Pawlenty campaigned for reelection as a supporter of stem cell research, but since the election has slid on the issue, and now says he would only support public funding if it did not include destroying embryos. The alternatives he supports, such as research that uses stem cells which are found in adults and in umbilical cords is not generally considered controversial.

As for the stem cells that come from embryos, the embryo is always destroyed in the process of harvesting the stem cells – a method of harvesting stem cells without destroying the embryo has not been developed. Dr. Firpo stated in her Scientist on the Spot feature, “The embryos we used to make human embryonic stem cell lines were from donors undergoing fertility treatments in a clinic. There were two types of embryos donated to my research program. The first (and most common) were those embryos that were discarded because they were determined to be too poor quality to make a woman pregnant. The second source was embryos that were frozen for the donor's use that were good quality, but were not needed for the donor's fertility treatment. The donors choose whether to keep the embryos, donate them or discard them. If they are discarded, they can choose to destroy them or to donate them for research.”

The University of Minnesota’s own Center for Bioethics has some great questions about embryonic stem cells and their use in medical research:

• When does a human embryo become a person?
• Should we use research methods that destroy human embryos to search for new therapies that could help people in the future?
• How far are we as a society willing to go to improve our health and lives?
• Where should the embryos for stem cell research come from?
• Will stem cell research lead to future genetic manipulation of cells? Will we cease to be human if that happens?
• What are we willing to spend on medical research and who should decide what is morally appropriate?

As for the accusations that Firpo’s research is illegal, Firpo states that she has been assured by the University that her research is legal, and that the statue Representative Severson referred to does not apply in this case.

With the federal government refusing to fund research into new embryonic stem cell lines, reports this week of a process that created them without destroying embryos in the process had scientists excited. But critics are claiming that the researchers overstated the implications of their work.

On July 25, 1997, researchers from Johns Hopkins University announced, at an international symposium on the ethics of human cloning and stem cells, that they had cultured human stem cells in their lab, using tissue taken from aborted human embryos. (Stem cells are the basic, unspecialized cells from which all other cells develop.) The researchers made the announcement before their research was published because they wanted to spark discussion that would establish guidelines for the ethical use of embryonic stem cells--a discussion that continues today.

Jul
19
2006

On Tuesday, the US Senate passed three bills regarding stem cell research.

Two were pretty uncontroversial: one encouraged stem-cell research using cells from sources other than embryos—adult bone marrow or hair follicles, or umbilical cord/placental blood. (The National Institutes of Health is already spending $571 million this fiscal year on this kind of stem cell research.) And one prohibited “fetal farming”—gestating fetuses for the purpose of providing tissue and other material for research.

The House of Representatives passed the bill about fetal farming, but voted down the bill promoting alternative stem cell sources. President Bush signed the ban on the commercial production of human fetal tissue into law today.

The third bill—which President Bush has just vetoed—would have expanded federal support of medical research using embryonic stem cells. Right now, researchers using federal funds can only study a handful of embryonic stem cell lines that existed before August 2001. The failed bill would have allowed federal funding for research on stem cells from thousands of unneeded embryos created in fertility clinics. (Couples with extra embryos resulting from fertility treatments would have had the option of donating them to research instead of having them destroyed by the clinic.) An override of the veto is unlikely.

What ARE stem cells?
Stem cells are simply cells that can develop into other types of cells. They can make copies of themselves indefinitely, and can become specialized for various body tissues. They are produced by embryos and also found in limited numbers in adults, but embryonic stem cells are pluripotent--they can become almost any kind of cell in the body--while adult stem cells are more limited. Scientists think they might be able to grow replacements for damaged tissues if they can coax stem cells to become the specific types of cells needed. Stem cells could someday provide treatments or cures for cancer, spinal cord injuries, burns, strokes, heart disease, Alzheimer’s and Parkinson’s, diabetes, and other ailments.

Mouse stem cells: (Courtesy NSF)
Mouse stem cells: (Courtesy NSF)

Why not use the pre-2001 stem cell lines?

In August 2001, the Bush administration and National Institutes of Health said that 60 stem cell lines had already been developed. Federal funds would be limited to research on those lines, and could not be used to create any more. But further investigation showed that less than 22 lines were actually available, and all of them had been maintained in culture dishes with blood products from rodents--scientists say the cells can’t ethically be used to treat people because of the danger of animal viruses and other contamination. Many of the lines aren’t aging well; if they don’t keep growing and dividing, they die, and some lines are accumulating mutations and other defects. Most research is limited to six of the stem cell lines. And they aren’t a very genetically diverse lot.

But the White House says,

"The use of mouse cells is standard scientific practice. ... As the Food and Drug Administration has indicated, the resulting stem cell lines can be carefully screened to ensure they are safe for use in any future clinical trials. Drug and biological products are routinely co-cultured with animal cells with no adverse consequences for the millions of people who have benefited from them."

Why not use private money?
Some labs have produced additional stem cell lines using private money, but researchers have to be scrupulous about segregating work on the newer cells from work done with federal money. The University of California, San Francisco, for example, is spending $5 million to set up a separate stem cell research lab where scientists can work without the federal restrictions. All the lab equipment they need already exists elsewhere on campus, but it can't be used for new stem cell work.

Some states see an opportunity in the federal restrictions. California announced that state money--$3 billion over 10 years--would be available for research into embryonic stem cells and therapeutic cloning. But the initiative is being fought in court. Connecticut has an 10-year, $100 million initiative. Illinois spent $10 million last year. New Jersey spent about $25 million in the last two years. And Maryland has approved a $15 million budget. But scientists in other countries are doing far more work with embryonic stem cells than scientists in the US. And losing out now means that the US could lose the eventual commercial applications developed through such research to the countries with looser regulations.

What's the issue with using embryonic stem cells?
Harvesting stem cells destroys a developing embryo. That's the crux of the whole issue. Those who oppose embryonic stem cell research say that the potential cures promised by stem cell research supporters offer false hope to some suffering Americans while encouraging the destruction of embryos to provide the cells. Members of the US Senate, debating earlier this week, expressed the gamut of opinions:

Senator Orrin Hatch (R-Utah) said,

"I do not question that an embryo is a living cell. But I do not believe that a frozen embryo in a fertility clinic freezer constitutes human life."

Senator Bill Frist (R-Tenn.), the Senate majority leader and a transplant surgeon, said,

"I believe that the progress of science and a pro-life position demand that Congress can send a message. I hope that we can redeem this loss of life in part by using these embryos to seed research that will save lives in the future."

Senator David Vitter (R-Louisiana) said,

"...I firmly believe that [neither] Congress, independent researchers nor any human being should be allowed, in effect, to play God by determining that one life is more valuable than another."

Senator Tom Coburn (R-Oklahoma), who is also a physician, said,

"The fact is, there is not one cure in this country today from embryonic stem cells."

Senator Tom Harkin (D-Iowa) said,

"So the choice is this ... throw [the embryos] away or use them to ease suffering and, hopefully, cure diseases."

Senator Sam Brownback (R-Kansas) said,

"We do not need to treat humans as raw material."

and

"It is immoral to destroy the youngest of human lives for research purposes. We don't need to do it."

Public opinion polls show that 70% of Americans support embryonic stem cell research. What do YOU think? Should the US government help fund it?

American universities (including University of California, San Francisco) are trying to create stem cell lines using cloned human embryos. (This is what South Korean researchers claimed to have done in 2004 and 2005; the lab later admitted that they'd fabricated their research.) Check the NPR story on who's in the business, how they're paying for it, and what the ethical issues are.