Ambiguous myelin
In recent years, researchers have increasingly considered stem cell-based therapy as a potential method for repairing damaged nerve cells. However, there are numerous natural barriers – various proteins and lipids that accelerate the transmission of impulses through adult nerve fibers, but at the same time prevents the growth of neurons.
Scientists from the University of California, San Diego, led by Professor Mark Tuszynski, found that the myelin protein in adult rats stimulated the growth of axons in rat neuron progenitor cells (CPN) and neuron stem cells (SCN) formed from induced pluripotent human stem cells.
Tushinski's laboratory, together with colleagues from Germany and Singapore, observed the appearance of neuronal processes from CPN and TFR growing on a myelin substrate in Petri dishes. Processes (neurites) are of two types: axons that transmit a signal to other neurons, and dendrites that receive signals. Both of them added up to 50 millimeters in the experiment. For comparison, adult axons grow by 1 mm during the same time.
Other studies have been conducted on rats after spinal cord injury. The authors found that rat CPN and SCN from induced pluripotent human stem cells after implantation into the injury zone caused the appearance of a large number of axons going mainly into the white matter.
By studying in detail the structure of myelin, which is known to inhibit the growth of axons of adult neurons, Tushinsky and his colleagues identified a neuronal growth regulator (1Negr1). It is a potential mediator between myelin and axons, contributing to their growth. Negr1 is involved in the processes by which neighboring cells interact with each other. Growth factor plays an important role during embryonic development, when neurons grow rapidly, but subsequently myelin begins to have an inhibitory effect.
The obtained data demonstrate the advantage of implantation of stem nerve cells over stimulation of restoration of damaged axons of adult neurons.
The results also confirm the validity of the developing approach based on neuronal progenitor cells and stem cells as a promising method for repairing spinal cord injuries. The authors note the need for further study of the stimulating effects of myelin on these cells. The information obtained can be used to restore nerves after spinal cord injury.
Article by Gunnar H. D. Poplawski et al. Adult rat myelin enhances axonal outgrowth from neural stem cells is published in the journal Science Translational Medicine.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru According to UC San Diego News Center: In a Break with Dogma, Myelin Boosts Neuron Growth in Spinal Cord Injuries.