Washington, Apr 8 : Researchers have shown that dopamine-producing neurons, when transplanted into adult rat brains, may help in the treatment of behavioural symptoms linked to low dopamine levels, like Parkinson's disease.
In the study, led by Marius Wernig, a postdoctoral researcher in Whitehead Member Rudolf Jaenisch's lab, the researchers used rodent model for transplanting the neurons taken from reprogrammed adult skin cells, which were successfully integrated into foetal mouse brains and resulted in a reduction in Parkinson's disease symptoms.
"This is the first demonstration that reprogrammed cells can integrate into the neural system or positively affect neurodegenerative disease," said Wernig.
This study comes in line with an earlier research showing that mice with a human sickle-cell anemia disease trait could be treated with adult skin cells that had been reprogrammed to an embryonic stem cell-like state.
However, in the neural experiments the researchers induced pluripotent stem cells (IPS cells), created by reprogramming adult skin cells using retroviruses to express four genes (Oct4, Sox2, c-Myc and Klf4) into the cells' DNA. Later, they used techniques originally developed in embryonic stem cells to differentiate these IPS cells into neural precursor cells and dopamine neurons.
In order to find out the therapeutic potential of the IPS cells, the researchers used a rat model for Parkinson's disease, a human condition caused by insufficient levels of the hormone dopamine in a specific part of the midbrain. Later, they killed the dopamine-producing neurons on one side of the rat brains to mimic this state. After that, the differentiated dopamine neurons were grafted into a part of the rat brains called the striatum.
After eight weeks of transplantation, the researchers discovered that the dopamine neurons had extended into the surrounding brain.
"This experiment shows that in vitro reprogrammed cells can in principle be used to treat Parkinson's disease. It's a proof of principle experiment that argues, yes, these cells may have the therapeutic promise that people ascribe to them," said Jaenisch.
The researchers are hopeful that this work could eventually be applied to human patients.
The study was published recently in the online Early Edition of PNAS.