Thursday, December 15, 2005

Stem Cell Chromosomal Issue Identified

Stem Cell Chromosomal Issue Identified

Researchers at Columbia University Medical Center have found that stem cells and progenitor cells will divide if their chromosomes are tangled, and they speculate that cancer-causing cells are also lacking the mechanism which is supposed to prevent division in this situation. This may also explain how cancer causing cells arise from normal stem cells.

Chromosomes are naturally tangled in a cell, but if they are not disentangled before cell division, the new cells can wind up with the wrong number of chomosomes. According to the press release, available on EurekAlert, “The research also points to potential obstacles involved with stem cell therapies. In the lab, stem cells are pushed to divide many times more than they normally would divide in an organism. The more stem cells divide, the more likely they are to acquire abnormal chromosome constitutions. Further research will be necessary to understand and address these risks.”

Fused Stem Cells Possible?

Fused Stem Cells Possible?

The BBC reports that the New Scientist reports that researchers at Oregon Health and Science University have found “fused” adult stem cells to be effective, but that researchers in the UK are less certain. According to the story, the researchers showed that mice with a particular liver disease can be cured by injecting their livers with adult bone marrow stem cells, which then “fuse” to the existing cells. Previously when stem cells and regular cells fused, the new cell had twice as many chromosomes as normal and had trouble dividing; but this time the cells reverted to the right number of chromosomes, for as yet unknown reasons.

The director of the Stem Cell Biology Laboratory at King's College London, said fusion’s potential was limited and that, “It has to be remembered this is coming out of the US, there is a political agenda.”

How interesting that the federal funding restrictions on embryonic stem cell research are causing other stem cell research to be seen as suspect across the Atlantic.

Feathers and Stem Cells

Feathers and Stem Cells

Move over, hair follicles, here come feathers. Researchers at the University of Southern California have analyzed the stem cells that are involved in the growth of bird feathers. The press release, available on EurekAlert, says,

Feather stem cells are of interest to scientists because of their profound regenerative abilities. A bird in nature molts twice a year. With more than 20,000 feathers on the average bird, [Cheng-Ming] Chuong notes, that means there are a lot of active, ongoing regenerative events in an adult bird.

The researchers identified the stem cells on feather follicles and studied their proliferation and differentiation. They found that when the bird loses its feathers through molting, it leave behind a ring of stem cells in the follicle. This stem cells then generate the replacement father. The scientists also found that the orientation of the ring of stem cells was related to the type of feather generated.

Chuong, the lead researcher, said that what the study really helps with is in identifying how stem cells are involved in the natural process of organ growth and development, which has implications for human organs.

Key Gene in Brain Stem Cell Differentiation Identified

Key Gene in Brain Stem Cell Differentiation Identified

Researcher at the Oregon Health Sciences University have identified a gene which is crucial for stem cells to differentiate into brain cells. The press release can be found on EurekAlert.

Neural stem cells begin by differentiating into neurons, then later start differentiating into glial cells. (Glial cells are “supporting tissue that is intermingled with the essential elements of nervous tissue,” according to a medical dictionary.) The researchers were interested in why the stem cells made this switch.

The scientists did their research on a gene which had been previously studied in relation to cancer but not the nervous system. They bred mice which lacked the gene and found that embryos developed with smaller brains and almost no glial cells. In another experiment, when the gene was removed from neural stem cells in a culture, the stem cells developed into neurons but not glial cells.

The scientists believe that this research has potential for the eventual treatment of neurological disorders such as Parkinson’s, either through drugs or through the replacement of neurons.

Hwang’s Research Alleged to be “Faked”

Hwang’s Research Alleged to be “Faked”

The Times (of London) reports that one of Hwang Woo-suk’s research collaborators said Hwang admitted to fabricating some of the material in his human cloning paper. The research team member, Roh Sung-il, said that Hwang admitted to fabrication when Roh visited him in the hospital. Roh was the doctor who provided compensation to egg donors without Hwang’s knowledge. (See “Korean Donors Were Paid For Eggs,” Blog post 11/21/05.) The article says,

"Professor Hwang admitted to fabrication," Dr Roh told the MBC, a Korean television station. "Hwang said there were no cloned embryonic stem cells at all and he did not know that."

(MBC is the television station that has come under fire amidst allegations that journalists working on a documentary program which was to expose Hwang’s work as fabricated coerced people to lie about Hwang. Will they now be exonerated? Or are there still journalistic ethical issues? Who lied when?)

Gerald Schatten of the University pf Pittsburgh, whose withdrawal from collaboration with Hwang began the extensive round of questions and doubts, has now asked that his name be removed from the paper that was published in Science. According to the Times, Roh said that Hwang would ask for a formal retraction of the article; the journal has not yet received a request, though it was contacting Hwang for clarification.

The Times says,

Dr Roh, who provided Professor Hwang with the eggs he used as raw material for his cloning experiments, said that while the scientist appeared to have successfully created cloned stem cells in the first place, most of these had subsequently died because of a virus infection. The team then substituted other stem cell lines, and manipulated data to make it look as if they shared the DNA of the patients from whom they were supposed to have been cloned, he said. The remaining two lines of cloned stem cells were frozen, but it was not known whether they had survived.

Another source, The Korea Times, further quotes Roh as saying that, “But I decided to go public because Hwang today made comments totally contrary to what we have believed is right. I need to clear away people’s suspicion and anguish.” It also reports that a professor at Seoul National University confirmed Roh’s claims and said there are no embryonic stem cells. The two (out of 11) stem cells lines that are still claimed to be genuine are frozen, and members of the team are trying to thaw them to prove that they are cloned.

A New York Times article reprinted in the International Herald Tribune describes the issue of the duplicate photograph:

In the Science article, the cell colony is labeled as being the fifth of Hwang's human embryonic cell lines derived from a patient's cells, but in the Biology of Reproduction article it is designated as an ordinary embryonic cell line generated in the MizMedi hospital in Korea, presumably from surplus embryos created in a fertility clinic.
The story also reports that critics say a prior article, the first (and apparently only) one to describe successful somatic cell nuclear transfer (cloning), shows evidence of either an abnormality in a DNA trace machine or hand manipulation of the data.

A Reuters story reports that there will be a news conference by members of Hwang’s research team tomorrow.

Personal note here—was I too quick to believe in Hwang when the MBC TV station accused him of faking his results? Well, I don’t know. No other scientist had admitted to doubt at that time—as of last week, the journal Science was still saying that the duplicate photos were an error. Schatten had withdrawn citing ethical issues about the egg source, not fraudulent data. At the time I was going with what seemed to be the consensus of the scientific community, that the ethical violations did not change the results of the research. Right now I am in a position where my faith in the peer review and collaborative research process is somewhat shaken—why didn’t Schatten see these errors? Why didn’t the journal editors at Science? Why did all of Hwang’s team stay silent until now? (I can see multiple motives, including the possibility that the work was done in such a way that they did not actually know about the results, so I don’t want to appear to cast blame on them at this point—I just want to hear their story.) If Roh had not come forward, would the university’s inquiry have eventually revealed the deception?

My whole feeling is one of sadness.

I want to end with a statement from Scientific American, which I will quote at length because I think is important to see their words and not my paraphrase of them:

With considerable disappointment, the editors of Scientific American are immediately removing Dr. Woo Suk Hwang from his honored position as Research Leader of the Year on the 2005 Scientific American 50 list. . . .

The allegations of ethical misconduct were very troubling, but Scientific American’s editors felt it was important to give Dr. Hwang the benefit of the doubt until their veracity could be determined. Even when those charges were borne out, we respected that the ethics of accepted practice in this area of science were still somewhat murky, and we declined to judge him too quickly, although his cover-up of those problems was clearly wrong.

However, scientific fraud is an unforgivable offense against the enterprise of research, and in this case, it completely invalidates the selection of Dr. Hwang for inclusion in the Scientific American 50. Dr. Hwang’s deceit misled Scientific American along with the international scientific community. We regret, in writing about his work and awarding him a place among key technology leaders, having unknowingly misinformed readers about his actual accomplishments. We are also deeply concerned about the lasting damage that this fraud may do to the reputation of stem cell research, which we continue to regard as a highly worthy endeavor generally pursued by scientists keeping to a far higher standard of honesty and ethics. --The Editors