How Does It Work? Stem Cells
We’ve all heard about stem cells and their use in medical research. These days they are in the news as often as global warming, but what do they do, why are they important and how can they be so controversial?
Even though they are no bigger than a full stop, every developing embryo contains dozens of stem cells. They are the building blocks of the human body, starting off with no assigned jobs but having the potential to become any cell, tissue and organ in the human body; such cells are called pluripotent cells and they can self-renew or reproduce themselves.
There are two kinds of stem calls: embryonic and adult. Embryonic cells grow into a foetus and become all the different cells required by the body. Adult stem cells are found in the brain, bone marrow and other organs, and help repair damaged cells in other parts of the body. The embryos are obtained from reproduction or cloning; the way scientists do this is by taking the inner cells (usually where the stem cells are) from a three or four day old embryo (which has about 100 cells) and culturing them in the laboratory where they are left to replicate. Those that do not turn into a specific organ (called stem cell line) can then become any cell. Adult stem cells are made in the same way but are harder to grow in the lab.
Although scientists know how to extract and grow stem cells, they still don’t know the mechanisms by which they change into the separate organs. There are a lot of triggers and chemical changes involved with growing these cells that have to be correct before organs can be re-grown. The other problem with growing these cells is that there is always a chance that the body rejects them when they’re put inside a new patient. Adult stem cells have a lower rejection rate than embryonic ones. Potentially, they can be used for two functions. The first of these is to test products on cells that belong to specific organs or that are essentially natural, this would give a far quicker response than waiting for the results of long medical trials. Secondly, you can use the stem cells for cell-based therapy - repairing cells or tissues that have been damaged during an injury or through disease. Damaged heart cells following a heart attack in rats have been repaired in this way.
You could return memory to an Alzheimer’s patient, replace skin lost after a bad burn or enable someone in a wheelchair to walk again. They may also be able to grow whole organs in a laboratory then transplant them back into a patient who has had liver, kidney or lung damage - the possibilities are limitless.
Stem Cell Controversy
The debate surrounding stem cells comes from how the cells are harvested. Whether the embryo is conceived or cloned, it must be subsequently destroyed; many people, in particular religious leaders, claim that this is tantamount to murder. Adult stem cells can certainly be used instead of embryonic cells, and altered to act like those from embryos - it seems adult cells are more versatile than previously thought. The second problem, surrounds whether it is morally right to take cells that come from a cloned embryo and implant them into a woman so she can give birth. The issue of cloning has already brought up some heated ethical and political debate in labs, churches and homes around the world: stem cell research adds a frighteningly realistic slant on the debate. This technology is no longer the stuff of science fiction, it’s here now.
How other stuff works:
- 'Musical' - Didgeridoo
- Interesting - A is for Amino Acids
- Cool - B is for Black Holes
- Background - C is for Cells
- Essential - G is for Genes
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