Nerves in a test tube – another step
Scientists at the University of Pennsylvania, working under the guidance of Professor Douglas H. Smith, have demonstrated the possibility of growing three-dimensional structures from nerve cells, which over time can be used to repair damaged areas of the nervous system.
Despite the fact that the transplantation of neurons in order to repair damage to the nervous system has shown good results in animal experiments, the transfer of this approach to clinical practice is practically impossible today. The reasons for this are the lack of sources of viable neurons suitable for clinical use and appropriate techniques for repairing extensive damage to nervous tissue.
In an earlier work, the authors showed the ability to control the direction of growth of axons – large processes of nerve cells – using mechanical stress. To do this, they cultured the neurons of the nerve nodes of the posterior roots of the spinal cord of rats in plastic cups with a nutrient medium. Gradually, the axons of neurons growing on different cups stretched out and formed synapses. Over a period of time, the cups were very slowly moved away from each other using a computer-controlled system. As a result, long strands of living axons were formed. Such cultures were placed in a collagen matrix and rolled into "tubes", which were implanted in mice with spinal cord injuries. 4 weeks after the procedure, the authors found that the transplanted neurons not only remained viable, but also formed contacts with the recipient's neurons, thus forming a kind of "bridge" at the site of nerve tissue damage.
As part of the new work, the authors applied the described method to living human nerve cells. Neurons of the posterior roots of the spinal cord were obtained from 16 living patients during elective gangliectomy, and four neurons of the thoracic nerve were obtained from organ donors. The neurons were cleaned and placed in a specially designed container. Gradually stretching the axons in opposite directions, scientists have achieved the desired length of the processes.
The picture above shows individual neurons of the posterior–radicular ganglia (colored with various dyes); at the bottom is the central part of an artificial human nerve.
The neurons remained viable and capable of generating bioelectric potential–an electrical signal transmitted through nerve fibers–for at least three months. Axons grew at a rate of about 1 mm per day to a maximum length of 1 cm and formed the first artificially created structures of nervous tissue.
The results of the work indicate the possibility of using adult neurons for autologous and allogeneic transplants.
Portal "Eternal youth" www.vechnayamolodost.ru based on the materials of ScienceDaily
28.02.2008