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Stem cells are the body’s “master” cells.
A growing embryo must produce all the different cells that make up the human body.
It contains stem cells – cells which have the ability to be transformed into any cell needed for blood, bone or the brain.
Scientists believe that this ability of stem cells could be harnessed to provide medical treatments.
Stem cell uses
In some diseases, cells are lost or damaged.
Researchers are exploring ways of using stem cells to produce cells which could replace these.
Much research is currently focused on using new heart muscle cells to help heart failure patients, and on producing new brain neurons to treat people with Parkinson’s or Alzheimer’s diseases.
Stem cell sources
The most obvious source of stem cells is from embryos, just a few days after conception. An embryo’s centre is made up of a bundle of stem cells which can be extracted.
Stem cells which are more differentiated and therefore closer in form to specific cells – such as blood or brain cells – can be found in older foetuses.
Adult stem cells
The use of embryonic and foetal stem cells is controversial – many people believe that the early embryo is sacrosanct.
An alternative might be to find a source of stem cells in adults.
Scientists have found that certain bone marrow cells behave very like embryonic cells and can be transformed into different types of cell.
Stem cell potential
There are still many technological obstacles and ethical considerations to be overcome before stem cell therapy could be routinely used.
But there is potential for stem cells to be used to treat a wide variety of conditions – from diabetes, to strokes, to blindness.
A few clinical trials have already been carried out in humans.
http://www.cbsnews.com/stories/2004/07/28/politics/main632553.shtml