At present there is no effective treatment for Huntington's disease - a progressive disorder in which nerve cells in certain parts of the brain waste away or degenerate and affects muscle coordination.
However, according to a study published March 15 in the journal Cell Stem Cell, a special type of brain cell created from stem cells could help restore the muscle coordination deficits that are responsible for uncontrollable spasms, a characteristic of the disease. The researchers demonstrated that movement in mice with a Huntington's-like condition could be restored.
Su-Chun Zhang, a University of Wisconsin-Madison neuroscientist and the senior author of the study, said:
"This is really something
In the study Zhang, who is an expert in creating various types of brain cells from human embryonic or induce pluripotent stem cells, and his team focused on GABA neurons. The degradation of GABA cells causes the breakdown of a vital neural circuit and loss of motor function in individuals suffering from Huntington's disease.
According to Zhang, GABA neurons generate a vital neurotransmitter, a chemical that helps support the communication network in the brain that coordinates movement.
Zhang and his team at the UW-Madison Waisman Center, discovered how to generate large quantities of GABA neurons from human embryonic stem cells. The team's goal was to determine whether these cells would safely integrate into the brain of a mouse model of Huntington's disease.
The researchers discovered that not only did the cells integrate, they were projected to the right target and were able to effectively restore the damaged communication network and restore motor function.
Zhang says that the results were astonishing, as GABA neurons reside in the basal ganglia, a part of the brain which plays a vital role in voluntary motor coordination. However, the GABA neurons exert their influence at a distance on cells in the midbrain via the circuit powered by the GABA neuron chemical neurotransmitter.
"This circuitry is essential for motor coordination and it is what is broken in Huntington patients. The GABA neurons exert their influence at a distance through this circuit. Their cell targets are far away.
Many in the field feel that successful cell transplants would be impossible because it would require rebuilding the circuitry. But what we've shown is that the GABA neurons can remake the circuitry and produce the right neurotransmitter."
The findings from the study are vital as they indicate that cell therapy may be used in the future to treat Huntington's disease, and they also indicate that the adult brain may be more malleable than they previously thought.
Neuroscientists believe that the adult brain is stable and not easily receptive to treatments that aim to fix things, such as destroyed circuits at the root of diseases like Huntington's. In order for a treatment to work, it has to be created so that only the cells of interest are affected.
"The brain is wired in such a precise way that if a neuron projects the wrong way,
it could be chaotic."
According to Zhang, although the new study holds promise, it will take a considerable amount of time and effort in order to work up from the mouse model to human patients. However, as there is currently no effective treatment for the disease, the work could become the best hope for individuals suffering with Huntington's.
The study was supported by the U.S. National Institutes of Health and the Chinese Ministry of Science and Technology.
Written by Grace Rattue