Last reviewed and revised on March 1, 2012 By Anthony L.
Komaroff, M.D. Brigham and Women's Hospital Most diseases are
caused by the death of healthy cells in a particular organ. For
example, Alzheimer's disease is caused by the death of brain
cells (neurons) that are important in thinking and memory;
diabetes is caused by the death of insulin-producing cells in
the pancreas (an organ that lies beneath the stomach);
Parkinson's disease is caused by the death of brain cells that
produce a chemical called dopamine; and heart attacks cause the
death of heart muscle cells. Almost all the organs in our bodies
cannot, on their own, replace the cells that die (the liver is
an exception). Nor have we discovered medicines that prompt our
bodies to replace dead cells. Stem cells have the capability to
replace cells that have died, in different organs. In mice, stem
cells have in fact replaced dead cells, and cured the mice of
particular diseases (including heart muscle damage). That is why
there is such excitement abou