Scientists Grow Old Brain Cells from Patients� Skin Cells Researchers from the Salk Institute for Biological Studies have found a way to create aged brain cells from patients� skin samples for the first time.  Fibroblasts, which are cells in connective tissue, from older people are directly converted into induced neurons. 

�This lets us keep age-related signatures in the cells so that we can more easily study the effects of aging on the brain,� said study author Rusty Gage, a professor in the Salk Institute Laboratory of Genetics. 

Researchers believe this technique will be very helpful to scientists studying age-related diseases, such as Parkinson and Alzheimer.

The paper was published Oct. 8 in Cell Stem Cell.

In an older approach, skin cells were taken and turned into induced pluripotent stem cells, which could then be turned into any cell in the body, such as brain cells, for further study.  However, this technique did not guarantee cells with epigenetic signatures of older cells.  This made it difficult to study the aging of the human brain because researchers couldn�t create aged brain cells.

�As researchers starting using these cells more, it became clear that during the process of reprogramming to create stem cells the cell was also rejuvenated in other ways,� said author Jerome Mertens, a postdoctoral research fellow. 

The team attempted a new technique, and showed that it possible to directly convert skin cells to neurons, completely bypassing the stem cell precursor state.

To show this the scientists used both methods to create brain cells from skin cells of 19 people, aged from birth to 89.  In the first technique they prompted the cells to turn into brain cells using the induced pluripotent stem cell approach, and in the second they used the direct conversion method.  After, they compared the patterns of gene expression in the resulting neurons with cells taken from autopsied brains.

Patterns in the neurons resulting from the induced pluripotent stem cell technique were indistinguishable between young and old samples.  Different patterns of gene expression were recognizable using the direct conversion method, depending on the age of the person they were created from.

�The neurons we derived showed differences depending on donor age,� said Mertens. �And they actually show changes in gene expression that have been previously implicated in brain aging.�

For example, levels of a nuclear pore protein, called RanBP17, which plays a role in neurodegenerative diseases, were lower in neurons derived from older patients.

Researchers expect the new method will let scientists create aged heart and liver cells as well, but as of now the work only tested the effectiveness in creating brain cells.