There are four different types of stem cells: Embryonic, fetal, umbilical and adult stem cells. Embryonic cells are taken from human embryos, fetal cells are taken from aborted fetal tissue, umbilical cells are taken from umbilical cords, and adult cells are taken from adult tissue.
Stem cells are able to transform into many different types of cells, such as bone, muscle and cartilage cells. Because of this ability, stem cells have potential to treat diseases where different cells in the body are damaged or lost and need to be replaced.
A report in this week's Science supports the incredible potential that this kind of research offers in treating humans.
In certain mouse embryos, severe cardiac defects occur that are invariably lethal. Injecting stem cells (ES) into mutant blastocysts can rescue these organisms from mid-gestational lethality, restoring the mutant cells to normalcy. In addition, some benefit is also derived from injecting these cells into the female mouse peritoneum before conception.
Thus, ES cells have the potential to reverse congenital defects in a mammalian embryo even though the stem cells themselves do not become heart tissue. They secrete certain molecules that signal the heart cells to repair the defects developing in those tissues.
(Science, Vol 306, Issue 5694, 247-252 , 8 October 2004)
http://www.sciencemag.org
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