For the first time, researchers have clearly shown regeneration of a critical type of nerve fiber that travels between the brain and the spinal cord and which is required for voluntary movement. The regeneration was accomplished in a brain injury site in rats by scientists at the University of California, San Diego School of Medicine and is described in a study to be published in the April 6th early on-line edition of the Proceedings of the National Academy of Sciences (PNAS).
“This finding establishes a method for regenerating a system of nerve fibers called corticospinal motor axons. Restoring these axons is an essential step in one day enabling patients to regain voluntary movement after spinal cord injury,” said Mark Tuszynski, MD, PhD, professor of neurosciences, director of the Center for Neural Repair at UC San Diego and neurologist at the Veterans Affairs San Diego Health System.
Most of us are going to live to see the day when tissue engineering biotechnologies make it possible to repair types of damage that we now must live with. Got very worn joints? Damaged tendons that won't heal? Damaged vocal cords? Nerve damage in an extremity? All this stuff is going to become repairable.
Genetic engineering made this possible.
The UC San Diego team achieved corticospinal regeneration by genetically engineering the injured neurons to over-express receptors for a type of nervous system growth factor called brain-derived neurotrophic factor (BDNF). The growth factor was delivered to a brain lesion site in injured rats. There, the axons – because they now expressed trkB, the receptor for BDNF– were able to respond to the growth factor and regenerate into the injury site. In the absence of overexpression of trkB, no regeneration occurred.
Although functional recovery in the animals was not assessed, the new study shows for the first time that regeneration of the corticospinal system – which normally does not respond to treatment – can be achieved in a brain lesion site.
Scientists will continue to find ways to improve genetic engineering techniques. Cells will therefore become more controllable. Humans will become repairable just like cars.
|Share |||Randall Parker, 2009 April 08 10:27 PM Biotech Neuron Repair|