Developmental biologist Lorraine Iacovitti, Ph.D., associate director of the Farber Institute for Neurosciences at Thomas Jefferson University in Philadelphia and her co-workers had previously shown that by using a potion of growth factors and other nutrients in the laboratory, they were able to convert adult human bone marrow stem cells into adult brain cells. Human adult bone marrow stem cells also known as pluripotent stem cells normally give rise to human bone, muscle, cartilage and fat cells.
While nearly all cells looked like neurons with axonal processes, they invariably reverted back to their original undifferentiated state in two to three days.
Dr. Iacovitti and her co-workers instead attempted to grow the cells in a different way. Rather than an attached monolayer of skin-like cells, they grew the bone marrow cells in suspension as neurospheres groups of cells early in development akin to the way neural stem cells are grown.
They found that the newly differentiated cells didn't merely look like dopamine neurons, but expressed traits of neurons and related cells called astrocytes and oligodendrocytes cells derived from neural stem cells. What's more, the neurons produced tyrosine hydroxylase, an enzyme needed to make dopamine.
She reports her team's findings October 25, 2004 at the annual meeting of the Society for Neuroscience in San Diego.
The Jefferson scientists also found a second enzyme involved in dopamine production, and an important molecule called the dopamine transporter.
Interestingly, Dr. Iacovitti notes, some of the cellular markers that would be expected to be expressed