Human Stem Cells
October 5, 2011 by staff
Human Stem Cells, In a provocative experiment, the researchers said they used a cloning technique to create the first human embryonic stages that were part of the diabetic patients of which they were derived.
The experiment, published in the journal Nature, is part of a larger quest to make gentle, patient specific stem cells to treat many difficult diseases. Created 13 cloned human embryos early in partial clones were diabetic patients. Each embryo had three sets of chromosomes, an extra set-which means that they are abnormal and would not have been viable if implanted into a womb and carried to term.
If the technique is becoming a viable treatment, researchers would have to eliminate that extra set of chromosomes and efficient to create a human embryo clone.
The experiment marks closest scientists have come to the cloning of humans since the 2004 work done by a Korean scientist who claimed to have created the first human embryo clone derived from a stem cell line from it;. That work was shown to be fraudulent. While the latest study does not claim the same quantum leap that the experiment of 2004 was likely to cause controversy because it involves cloning human potential and the destruction of embryos.
“It is an early step in research toward a cure … devastating disease,” said Dieter Egli of New York Stem Cell Foundation Laboratory in New York and co-author of the study, which deliberately does not use the word “cloning “to describe the results. “I really do not know how hard it will be” to eliminate the extra set of chromosomes.
Scientists have long hoped to create fresh human tissues and the use of transplantation to treat a range of ailments such as heart disease and Parkinson’s. Ideally, fresh tissue must share the same DNA as the patient to avoid immune rejection, problems.
There are several ways to create fresh tissue. Master of stem cells that give rise to all kinds of tissues in the body, can be extracted from a six-cell embryo. But this approach is ethically controversial and avoid the problem of immune rejection.
Moreover, certain genes may add to the mature cells of a patient. This will reschedule at an embryonic stage and is created as a source of master cells without the problem of immune rejection or ethical controversy. However, this method is still far from safe or useful.
A third way is to use eggs to make the trick of rescheduling. That’s how Dolly the famous cloned sheep was made. Of cells in the skin of his mother was in another sheep’s egg, no longer had its own DNA-containing nucleus. That effectively “reset” the skin cells in an embryonic form, which was completed and resulted in a cloned Dolly.
While these experiments have succeeded in cloning various mammals, the “de-nuclear” egg approach has not worked so far in humans. Now, Dr. Egli and colleagues who have, in part, achieved through a simple movement: it took very core of the egg.
As a first step, we took the core DNA-carrying cells from the skin of diabetic patients and added to human eggs. The eggs are added reprogrammed cells, the creation of blastocysts, which are 6-10-cell embryos, each smaller than a pinhead. The researchers then derived stem cell lines from blastocysts, a movement that destroys the blastocyst.
The ultimate goal would be to transform stem cells into insulin-producing cells and put them back in diabetic patients without fear of immune rejection.
Scientists do not go so far as they knew that the embryos created had an extra set of chromosomes (originating from the egg) and the abnormal.
However, the eggs did successfully reprogram cells from patients skin stem cells teacher. As proof, the team became successful master stem cells in several cell types, including nerves, cartilage and muscle tissue.
“For the first time we have an experiment that really works, so you can optimize from there,” said Dr. Egli.
It will not be easy, since the technique is very inefficient. Dr. Egli and colleagues said they started with 270 eggs and have created 13 embryos in early stage. From these, which won only two viable stem cell lines.
The method also relies on human eggs, which can be difficult to obtain for research purposes.
The biggest technical problem is to get rid of the stem cells of the additional set of chromosomes. The team hopes that by experimenting with some other start-cells of the skin that could get a better result.
An editorial in Nature notes that the cells are still far from being useful outside a research setting “. No one called clinically relevant in the short term”
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