Neurons from stem cells take root in the brain

According to the article "Murine Embryonic Stem Cell-Derived Pyramidal Neurons Integrate into the Cerebral Cortex and Appropriately Project Axons to Subcortical Targets" published in The Journal of Neuroscience on January 20 According to the results of the work of scientists at the Stanford University Medical School (California), working under the guidance of Dr. James Weimann, neurons grown from embryonic stem cells, when transplanted to young animals, are able to fully integrate into brain tissue.

Healthy brain cells form clear stable relationships that ensure the normal functioning of the body. In experiments on mice, the authors demonstrated that stem cells can be pushed not only to transform into specific brain cells, but also to form the necessary relationships for the body.

The researchers devoted their work to the pyramidal neurons of the cerebral cortex, transmitting information to various organs and tissues of the body. Some of these cells provide muscle control. The death of these neurons in spinal cord injuries and amyotrophic lateral sclerosis (Charcot's disease) leads to muscle atrophy and paralysis. The results obtained by the authors give hope that over time these diseases can be treated by replacing dead cells with neurons grown from stem cells.

During the experiments, the scientists cultured embryonic stem cells for two weeks according to two specially developed protocols, only one of which brought them the desired results. By the end of the first "induction" week, the cells began to express genes characteristic of forebrain progenitor cells. During the second week, the cells differentiated and acquired signs of mature pyramidal neurons. After that, young neurons were transplanted into the brains of newborn mice, namely into the regions of the cerebral cortex responsible for vision, touch and motor activity.

Until now, specialists involved in the development of methods of cellular therapy of diseases of the nervous system have not been able to achieve the formation of full-fledged interneuronal contacts. In this case, as the transplanted neurons matured, their axons integrated into strictly defined areas of the brain, avoiding, no less importantly, inappropriate areas. For example, the processes of neurons transplanted into the visual cortex reached out to two structures located in the deep layers of the brain, the upper tubercle and the Varolian bridge, but did not integrate into the spinal cord, whereas the axons of neurons transplanted into the area of the cortex responsible for motor activity integrated exclusively into the spinal cord.

(The picture shows a neuron grown from a stem cell that migrated from the transplantation zone in the cerebral cortex and turned into a fully mature cell. The nuclei of the animal's own nerve cells are colored with blue dye.)

In their future work, the authors plan to reproduce the results obtained in adult animals and, eventually, in humans. They also hope to understand the mechanisms by which transplanted cells direct the growth of axons in the right direction, as well as to study the ability of these cells to restore given body functions, such as vision and the ability to move.

Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru According to ScienceDaily: Neurons Developed from Stem Cells Successfully Wired With Other Brain Regions in Animals.

25.01.2010