Neural Stem Cell Exits Throughout Our Lives
Neural stem cells found in adult brains exit throughout our lives. Neural stem cells form into three types of cells: oligodendrocytes, astrocytes, and neurons. Of the three types, neurons hold the most interest for scientists because neurons control the functions of the brain. Scientists are interested in learning if stem cells could be used to repair damaged neurons in the human brain. One specific possible use of neural stem cells is to treat Parkinson's disease. In Parkinson patients, the neurons that produce dopamine are damaged and destroyed. If specific dopamine-producing neurons could be created from neural stem cells, then perhaps these damaged neurons in Parkinson's patients could be replaced.
Parkinson's disease is named after the doctor who first wrote about it, Dr. James Parkinson. In 1817, he described the disease, which results when cells are damaged or die in the midbrain. These midbrain cells produce the chemical dopamine, which transmits signals in the brain. If these cells aren't healthy, then the signals between areas of the brain are disturbed. When enough cells that produce dopamine die, the patient develops Parkinson's disease symptoms. Treating Parkinson's disease with neural stem cells is important because this disease greatly impacts the lives of patients. Parkinson patients have problems that include limbs shaking, poor balance, stiff limbs, and slow movements. When these symptoms occur, the patients have trouble sustaining normal motion. Studies that have been done on primates with Parkinson's disease have been very successful. When they were injected with healthy neural stem cells from humans, primates who had severe cases of Parkinson's disease showed great improvements. These primates could eat and move better, they had fewer tremors, and were able to walk. One study in particular was conducted by a team made up of researchers from Harvard, Yale, the Burnham Institute, and the University of Colorado. These researchers used a group of eight monkeys in the study. All eight of these monkeys had severe Parkinson's disease. Human neural stem cells were injected into five of the monkeys. The other three monkeys did not receive neural stem cells. The monkeys who received the human neural stem cells improved greatly. The monkeys who did not receive the injections did not improve. This study is very encouraging. It shows the potential to use neural stem cells to help human patients. Equally important to the improvement the monkeys showed is that they did not have any adverse side effects. In the eight months following the injection of human neural stem cells, no tumors or toxic effects appeared in the monkeys. Although the studies are encouraging, transferring this result into therapies for humans is still a long way off. Many more studies need to be conducted and more needs to be learned about ways to correctly utilize neural stem cells. But considering how severe and debilitating Parkinson's disease is, this research really brings a great deal of hope to sufferers. If neural stem cells could be used to treat human patients the way these were used to treat the monkeys in this study, the impact could be immense. |