In a discovery that may force biologists to rewrite the textbooks on cell development, researchers succeeded in causing mature neural stem cells - from which the various nerve cells in the nervous system develop - to change their identity and become heart, lung, kidney, intestine, liver and other cells
by Tamara Traubman
"Right now this is basic academic research," said Dr. Jonas Friesen, the leader of the study, in an interview from his office at the Karolinska Institute in Stockholm. However, Friesen said that the discovery strengthens the hope that in the future they will be able to use mature stem cells to replenish the supply of cells that are destroyed in the aging process, such as muscle cells and bone cells, and to cure diseases caused by the destruction of nerve cells, such as Parkinson's.
As known to biologists until recently, only embryonic stem cells could develop into any of the cell types in the body. These are primary cells, which have not yet differentiated into the different cell types and exist only in embryos. However, once an embryonic stem cell develops into a certain type of cell, it cannot become another type of cell.
The breakthrough in embryonic stem cell research was achieved about two years ago, when two teams were able to independently grow human embryonic stem cells in the laboratory and preserve in them the ability to develop into all types of cells found in the body. However, the study of embryonic stem cells has provoked opposition, because the cells for research are taken from human embryos. The US Congress, for example, prohibited funding research in human embryonic stem cells from federal budgets.
The cells tested in the current study, published today in the scientific journal "Science", are mature stem cells. In these cells, the type of cell they will develop into has already been determined and they are found in tissues where a constant turnover of cells is required.
Friesen and his colleagues isolated neural stem cells from adult mice and injected them into mouse embryos and chickens. Examining the embryos revealed that the cells integrated in different places in the embryo - including the spinal cord, liver and stomach - and received the identity of the cells in those organs.
Friesen said he still doesn't know exactly what caused the adult stem cells to change their type. "Apparently, mature neural stem cells respond to molecules secreted by their new neighbors, and are affected by the signals that direct the development of the cells in the new place they have arrived at. But the nature of these signals is not completely known to us yet," he said.
Prof. Eduardo Mitrani, head of the program for developmental cell biology at the Hebrew University, said that Frissen's research is "exciting". According to him, "the research shows once again and in a clearer way that not only that, contrary to what we thought for years, there are cells in the brain that can produce new nerve cells, but that these cells can even produce other types of cells."
Although the first hints that adult stem cells can also develop into other cell types began to be received last year, other researchers had difficulty replicating the results of these studies, and the range of abilities of those cells was not known until now.
Prof. Yosef Itzkovich of Rambam, who was a partner in one of the teams that isolated the embryonic stem cells two years ago, said that the current research is equal in importance to the cloning of Dolly the sheep. "The concept of this research and of parallel works, constitute a concept of a revolution in biology, of paradigms that have completely changed," he said. He said the cloning of Dolly the sheep showed that it is possible to reprogram an adult cell and make it go back in time and become younger, while the current research shows that it is possible to reprogram the identity of cells. Itzkovich added that "these are two concepts that complement each other and make one of the most important revolutions in biology today."
According to Itzkovich, it is wrong to completely abandon the research of embryonic stem cells, because they are easier to produce and their capabilities are still greater than those of adult stem cells. He said that even in the use of adult stem cells, according to the model proposed in the study, ethical problems may arise, since the cells are grown in animal embryos.
{Appeared in Haaretz newspaper, 2/6/2000}
4 תגובות
Come on, why don't they be brave and try it on old people who are going to die anyway, and there are many people who were ready for the experiment,
They should think it's a shame in an advanced generation of the Internet if they don't manage to add 10 years to a person's life, that's how they think and it will work, I have no connection with the family and this strengthened my connection with my grandmother from whom I derive her character who knows how to communicate with people like an actor, and because This is important to me and also for my grandmother who deserves to live
Lisa:
I don't know how you expect Danny Ofen to notice your comment and respond to it.
Studies such as the current study and others (including some of those linked at the bottom of this article) are carried out, mainly to enable treatments of the type you described.
In other words - not only did they think about it in light of the development of technology, but they thought about it long before and following these thoughts they develop the technology.
This is not about replacing cells in the style of removing the damaged cell and inserting another under it (this is impossible with today's technology and probably with any technology that can be expected in the next hundred years) but rather about injecting new cells into the tissue in the hope that they will integrate into it by themselves, begin to function, and repair some of the damage.
I turned to Prof. Danny Ofen following an article I saw about changing stem cells into dedicated cells in the brain - has anyone thought about the experiment of designating stem cells for people who have had a stroke and whose physiological function is impaired? Can we help them? Can the stem cell experiment replace the brain cells damaged in the CVA event? Is it possible to locate the dead cells using SPECT imaging and replace them with stem cells that will be adapted to act in place of those that have died? Are stem cells replaceable at any age? I saw that you took the cells from the bone marrow, can this be done at any age? Is it worth trying to save thousands of people who are motorically or cognitively impaired and return them to the circle of people who can function independently and without the help of others?
I would love to hear your opinion and your answer on this matter.
Thanks in advance
Lisa Blau
Herzliya
experience.