Brain, Heal Thyself

In our bodies, organs have their own stem cells that replace injured and dead cells. But according to the conventional wisdom, the brain doesn't have stem cells. Instead, nature gives us need replacement. Nevertheless, the conventional wisdom on brain stem cell is changing these day. Samuel Weiss and other researchers maded mouse brain cells act like stem cells in the experiment. The result is that it can be possible to get cell in brain to act like stem cells for only one day. In 1992, Evan Snyder and his colleagues had removed stemlike cells from the newborn mice' brain. Snyder said that his manipulated cells meet the requirements of true stem cell. They can reproduce and maintain themselves, and they can give rise to all the major cell types in the brain. The marked cells had indeed differentiated in to neurons and other brain cells. After differentiating, the cell stopped dividing, just like normal brain cells because of some innate brain signal that dampens division. Snyder had found that his implanted cells could repair some kinds of brain damage. The cells get injured easily when the oxygen supply is cut off. Normal mature brain cells lost the ability to respond to brain signals, or the signals may have been suppressed. Snyder and his colleagues used stem cells to gene therapy. They put a gene into the cells that codes for an enzyme missing. The enzyme breaks down a cellular waste product in brain. The waste accumulates if there is no enzyme and it causing severe mental retardation and death. Snyder found the genetically enginered cells began producing the enzyme at levels thought to be sufficient to alleviate symptoms of the disease. The stem cells might naturally tend to spread and produce their crucial enzyme throughout the damaged brain. Weiss injection of egf into mouse brains spurred the growth of new neurons. These cells spread into regions near the subependmal layer and the striatum. This is so improtant because in people with Huntington's disease, neurons in this region die. The gap between experiments with mice and human cell therapy for brain damage is huge. Snyder and Weiss' experiment show us the human brain has the protenial to repair itself, and brain may have stem cells.


http://discovermagazine.com/1996/aug/brainhealthyself847/?searchterm=brain heal thyself