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  (Source: topnews.in)
Research could help those with cancer or anemia

McMaster University researchers from Hamilton, Ontario have found a way to create blood directly from skin without having to change a skin stem cell into a pluripotent stem cell. 

Dr. Mick Bhatia, study leader and scientific director of McMaster's Stem Cell and Cancer Research Institute in the Michael G. DeGroote School of Medicine, along with his team, have created blood directly from human skin in an effort to treat medical conditions such as anemia and cancer. The new technique can also use the blood in surgery from the patients' own skin without having to perform the intermediate step of transforming a human skin cell into a pluripotent stem cell

To do this, Bhatia and his team obtained skin fibroblasts, which is a type of cell that gives skin its form through the "scaffolding" of connective tissues. Once the skin fibroblasts were taken from volunteers, researchers then inserted the gene for OCT4 into the cells using a virus, and grew them in an "infusion of cytokines," which are signaling proteins that stimulate the immune system and communicate between cells. Usually, researchers have to transform a skin stem cell into a pluripotent stem cell before turning it into a blood stem cell, but this new research eliminates the middle step and converts skin cells directly into blood cells. 

"Bhatia's approach detours around the pluripotent stem cell stage and thus avoids many safety issues, increases efficiency, and also has the major benefit of producing adult-type l blood cells instead of fetal blood cells, a major advantage compared to the thus far disappointing attempts to produce blood cells from human ESCs [embryonic stem cells] or IPSCs [induced pluripotent stem cells]," said Cynthia Dunbar, head of the Molecular Hematopoiesis Section of the Hematology Branch of the National Heart, Lung and Blood Institute in the National Institutes of Health in the United States.  

Bhatia and his team worked on the study for two years. It is the first study to show direct conversion to a stem cell, and also the first to show direct conversion from skin cells to other types of human cells. Bhatia's study used young and old volunteers to show that age did not matter in the study.

"We have shown this works using human skin," said Bhatia. "We'll now go on to work on developing other types of human cell types from skin, as we already have encouraging evidence."

This study was published in Nature on November 7. 



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RE: I like the concept...
By jimhsu on 11/8/2010 5:12:54 PM , Rating: 2
This is actually a concern, though not in the sense alluded to here.

Retroviral gene expression in this case (OCT4, a well known proliferation signal for stem cells) is comprised of completely safe DNA (i.e. they aren't using oncogenic markers like c-Myc), and the virus payload is gone, so no crazy replicating viruses. HOWEVER, retroviruses aren't perfectionists when it comes to actually inserting their piece of DNA somewhere safe on your 3 billion plus letter genome. After all, they were designed to infect as many cells as possible, not perform precise surgery. "Most" (99%) of the time, it'll get inserted in some junk region of human DNA, but some of the time, it could be inserted into a functional gene, or even worse, an important tumor suppressor gene on your genome. If that happens ... well, you have all sorts of nasty problems like cancer to deal with.

HENCE, the reason they are looking for more specific vectors and non-retroviral approaches (i.e. plasmid transfection). As someone in the periphery of the field though, I can tell you that the efficiency of all non-retroviral approaches frankly sucks right now.


RE: I like the concept...
By jimhsu on 11/8/2010 5:20:21 PM , Rating: 2
To elaborate a bit more - recently (last few years), there has been work on making retrovirus integration more specific (wikipedia mentions zinc finger nucleases and beta-globin locus control regions), but perfecting it is still an emerging science. http://en.wikipedia.org/wiki/Gene_therapy provides a decent overview of the field.


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