• Question: how do stem cells help in brain development?

    Asked by bcarter to Emma, James, Jayne, Kara, Sharon on 24 Mar 2011 in Categories: .
    • Photo: Sharon Sneddon

      Sharon Sneddon answered on 18 Mar 2011:

      Hi bcarter.
      Stem cells are really important in brain development.
      The brain grows at an amazing rate during development. At times during brain development, 250,000 neurons are added every minute! At birth, almost all the neurons that the brain will ever have are present. However, the brain continues to grow for a few years after birth. By the age of 2 years old, the brain is about 80% of the adult size.

      Brain stem cells are called neural stem cells and it is these that are responsible for dividing to populate the brain with all the cells it needs during development. Neural stem cell (NSCs) are the self-renewing that generate the main cell types of the brain and the nervous system, so without stem cells, you wouldn’t have a brain!

      If you take the cells out of a developing brain, they will make neurons and astrocytes and glial cells and grow in culture showing that these cells are stem cells.

      After birth, new neurons are also made by stem cells, but not as in such great number as when the brain is developing. This happens in 2 main areas, the subventricular zone which line the lateral ventricles of the brain, this is where the new cells migrate to the olfactory bulb, and in the subgranular zone which is part of the “dentate gyrus of hippocampus” I’m not really a brain expert, so I’m not sure what that part of the brain does, but it sounds important!
      It’s thought that making new neurons in adulthood is important for learning and memory.

      For people with diseases like Parkinsons or Alzheimer’s, stem cell therapies show great promise as if we can develop ways of transplanting in nice new healthy neurons, or dopamine producing cells, we may be able to reverse the effects of these diseases.

      You may wonder, “How does the brain continue to grow, if the brain has most of the neurons it will get when you are born?”. The answer is in glial cells. Glia continues to divide and multiply. Glia carries out many important functions for normal brain function including insulating nerve cells with myelin. The neurons in the brain also make many new connections after birth.

    • Photo: Kara Cerveny

      Kara Cerveny answered on 18 Mar 2011:

      Great question that I’ll try to answer. In terms of brain development, embryonic stem cells are sequentially specified first to turn into cells that will part of the nervous system and then depending where they are in the embryo (and what external signals they receive and where/if they migrate to another section of the embryo) they either stay as neural stem cells or become neurons or support cells (called glia). If the neural cells are not properly regulated by the milieu around them, then they can either make too few or too many of particular types of neurons. This is one of those questions that could be more easily answered with a picture and animations and I’ll try to find one and send it.

    • Photo: James Chan

      James Chan answered on 18 Mar 2011:

      hi there, that’s an intriguing question.
      Brain development is fascinating. My best friend is a brain surgeon and he tells me that he sees some very young babies who have suffered massive brain damage. If this had happened to an adult, this would have made them completely disabled for the rest of their lives, but the amazing thing is, babies have this ability to adapt so that the remaining healthy part of their brain can take over. So if very young people have such an amazing capacity to recover, then you could argue that stem cells may not be needed in a lot of cases. Where there IS a lot of research in stem cells in brain problems is in dementia, and things like Parkinson’s disease and multiple sclerosis. There is a Brain Repair Centre in Cambridge that specially looks at these and they have been trying transplanting stem cells in patients with parkinson’s disease. It’s pretty cool stuff.

    • Photo: Emma King

      Emma King answered on 21 Mar 2011:

      hi bcarter – stem cells help in brain development because they grow neural cells, which allow us to think. One of the stem cell therapy trials which has just started is looking at ways to regrow brain tissue after a stroke. The symptoms of stroke are normally due to brain tissue being lost, so there is a hope that stem cells can alleviate those symptoms by regrowing parts of the brain. I hope that the technology works!

    • Photo: Jayne Charnock

      Jayne Charnock answered on 24 Mar 2011:

      Hi bcarter

      Great question. Well, we all start off life as a stem cell, and that stem cell makes more of itself, and they then decided to become different sorts of cells, some of which will be nervous cells or neurons. what is really interesting is how those cells then know where to go to form the brain, we call this ‘patterning’ and its the result of lots of different clever signals being sent to direct the cells. stem cells have really helped us understand alot more about human development because we can reproduce (or try to!) what is happening in human development but on a smaller scale in the lab

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