• Question: Mainly aimed at Susanne, but I welcome answers from others. Tell me more about stem cells please, I hear about them often enough, but don't always understand!

    Asked by jackyboy1999 to Clare, Mariana, Robert, Susanne on 21 Nov 2012.
    • Photo: Robert Insall

      Robert Insall answered on 21 Nov 2012:

      Jackyboy,

      The idea about stem cells is that there are cells specialized to be parents. They grow and divide like others, but instead of specializing in a particular job they specialize in deciding whether or not to grow and inseeding all the other cell types.

      It’s particularly important for cancer, because there are (probably) cancer stem cells – they are different from the body of most tumours, and much harder to kill with chemotherapy.

      Susanne will surely give you a longer answer.

    • Photo: Susanne Muekusch

      Susanne Muekusch answered on 21 Nov 2012:

      Hi jackyboy,

      uuuh, this is a tough one. I will try to give you a focused overview- if you have any follow up questions please leave a comment!

      As Robert already said stem cells are “unspecialised” cells. They are able to produce more of their own kind and plus specialised cells. That’s the definition of a stem cell! But what does that mean? Here come a few examples about what stem cells do, what different types of stem cells there are and where you might have heard about them.

      We all started out as a single stem cell in the womb- the fertilised egg, which is a so called embryonic stem cell. When it fist starts dividing, all the cells are equal and they are all embryonic stem cells. This cells are able to give rise to ALL cell types found in the human body- and will do so to form a baby. Along the process, the embryonic stem cells will specialize themselves into tissue specific stem cells. Although they are still stem cells, they can now only produce the different cell types found in one tissue. There is for example a blood stem cell, which can produce all the different blood cells, but it cannot produce nerve cells. And there is a neural stem cell, which can produce the different brain cells but no blood cells. These tissue specific stem cells are still present in grown ups, unlike embryonic stem cells.

      Stem cells are sometimes in the media because of their therapeutic potential. Some diseases (or their symptoms) are caused by specialised cells which are dying, like in Parkinsons disease or multiple sclerosis. In this two diseases nerve cells are dying. The idea with the stem cells is that they can be a source of new nerve cells. Unfortunately, this does not really work yet. While we do understand how to get new nerve cells, the problem is to get new nerve cells that are wired in the right way to all the other nerve cells in the brain.

      Maybe you have heard about bone marrow transplantation for people with leukemia. In the bone marrow are blood stem cells, so it is a stem cell transplant! It is necessary because the leukemia treatment kills both leukemic cells and stem cells.

      Stem cells from the umbilical cord. When a baby is born some companies offer the parents to isolate stem cells and store them (for a lot of money). Personally, I think the applications and number of diseases you could use them for, are so limited that it is not worth the money. Right now it is a lot of “they might be helpful in future to cure a lot of diseases” or they might not.

      Human embryonic stem cells have been critiqued a lot because of ethical reasons- you have to kill an embryo to get them. In Germany it is forbidden to create new embryonic stem cell lines.

    • Photo: Mariana Campos

      Mariana Campos answered on 21 Nov 2012:

      The controversy that Susanne talk about with stem cells comes from the fact that they come from an embryo, so one would need to generate an embryo, get the stem cells and then destroy it. This, of course, generated discussion between the public, politicians, scientists and religious groups. Because an embryo is destroyed after stem cells are removed, some people think that is the equivalent of killing a potential life.
      Scientists are trying to find better techniques that would avoid destroying the embryo. Some scientists managed to do the reverse of what usually happens in the human body: they took adult cells that were completely specialized and they gave them the right chemicals. With this they manage to create stem cells out of them. This was a major discovery and would allow us to get stem cells without needing to generate and destroy embryos. Was such a big the discovery that the scientists got the Nobel prize this year.

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