EMBRYONIC STEM CELLS VS. FETAL TISSUE

   More than a year ago, controversy erupted over the University of Nebraska Medical Center's use of aborted fetal tissue for research on Alzheimer's disease.
    Now there's debate over embryonic stem cell research, which Medical Center researchers say they are not doing.
    What's the difference?
    Plenty, say the scientists.
    "A stem cell is a cell that hasn't decided what it wants to be in the future. It has the potential of becoming anything," said Anuja Ghorpade, a senior scientist with the Medical Center's Center for Neurovirology and Neurodegenerative Disorders.
    Embryonic stem cells come either from embryos in the first few days after conception or from the developing sperm and egg cells from aborted fetuses.
    Fetal tissue research uses cells that have already made that decision. They have become neurons, astrocytes and microglia - the three specialized types of cells found in the brain.
    Ghorpade and other researchers use those cells to understand what happens when people suffer from Alzheimer's disease and other progressive brain disorders.
    "Many of the human degenerative diseases are unique to humans," she said. "We use animal models, we use transformed (cancerous) cell lines, but fetal neurons are important because they are the primary cells that are affected in the brain.
    The Medical Center researchers use brain cells primarily from aborted fetuses. So far, fetuses provide the only source of neurons that will stay alive and develop networks in the laboratory, Ghorpade said. The other two types of brain cells have been obtained through rapid autopsies of both children and adults.
    Whether Medical Center scientists ever embark on human embryonic stem cell research, fetal brain cells likely would be needed for the neurodegenerative disease research, Ghorpade said.
    "Right now we don't know what is going wrong in Alzheimer's disease so we want to use cells that have the closest function," she said. "I don't see any particular benefit of using embryonic stem cells except that we would get even more controversy."