Within the last 20 years neuroscientists have shown that new neurons are generated in the brain throughout the lifespan. This finding opened a new area of research aimed at understanding if adult neural stem cells can be used in therapies for neurodegenerative diseases.
A challenge with this approach is that there are fewer neural stem cell in the aged brain and the loss of stem cells occurs at just the time when neurodegenerative diseases are most common. But a new study is providing important information that neural stem from an aged brain still have the capacity to mature into functional neurons.
A team of researchers from the Wallenberg Neuroscience Center in Lund Sweden led by Dr. Zaal Kokaia examined the properties of neural stem cells at different stages of the lifespan. In an elegant set of experiments they characterized changes in key genes that effect the ability of neural stem cells to proliferate and mature into functional neurons.
The research group confirmed that there are fewer neural stem cells in the aged brain. It is both the environment in the aged brain and changes in the stem cells that reduce their ability to generate new neurons. Stem cells from the aged brain express less of important neural stem cell markers, key transcription factors, and neurogenic factors. But all is not lost. The neural stem cell that remain in the aged brain can produce functional neurons if the cells are cultured outside of the aged brain environment. Furthermore, the new neurons functioned just like those from younger brains.
Dr. Kokaia's research provides an important new finding about the capacity of adult neural stem cells to proliferate and mature into new neurons. Embryonic stem cells give rise to the largest number of functional neurons and will continue to be the most suitable for transplant purposes. This study shows that neural stem cells from aged brains can produce functional neurons, giving new hope that adult stems cells can be used to treat neurodegenerative disease in the elderly.
For more information about Dr. Kokaia's research you can look at his website.
For more information about the research paper on neural stem cells in the aged brain you can read the abstract for the paper published in the Journal of Neuroscience.
The Journal of Neuroscience, April 8, 2009, 29(14):4408-4419;
Neural Stem and Progenitor Cells Retain Their Potential for Proliferation and Differentiation into Functional Neurons Despite Lower Number in Aged Brain
Henrik Ahlenius,1,4 Violeta Visan,2,4 Merab Kokaia,3 Olle Lindvall,2,4 and Zaal Kokaia1,4
1Laboratory of Neural Stem Cell Biology, 2Laboratory of Neurogenesis and Cell Therapy, and 3Experimental Epilepsy Group, Section of Restorative Neurology, Wallenberg Neuroscience Center, University Hospital, SE-221 84 Lund, Sweden, and 4Lund Stem Cell Center, SE-221 84 Lund, Sweden