Dr. Patricia Braga and her team at the University of Sao Paolo, in collaboration with Alysson Muotri, professor of pediatrics and cellular and molecular medicine at UC San Diego, are using dental stem cells from donated baby teeth to grow neurons and examine the role of astrocytes in the expression of Autistic traits such as language impairment, repetitive behaviors and sleeping difficulties. Dr. Braga has used dental pulp stem cells from two groups of patients - children with Autism and a non-autistic control group, and directed their stem cells to differentiate into brain cells in vitro. When allowed to grow, the stem cells developed into clusters that contained the star-shaped brain cells called astrocytes, as well as fully grown neurons. Upon closer inspection, the astrocytes and neurons from children with Autism showed significant functional differences compared to the control group cells. Autistic astrocytes release excessive amounts of an inflammatory molecule called interleukin-6 (or IL6), which, in concentrated amounts, can harm nearby neurons and hinder their functionality. Additionally, the neurons from Autistic children were found to fire less frequently, form fewer synapses (connections with other neurons) and release less glutamate, which is used to excite surrounding neurons and transmit signals.
Researchers led by Dr. Su-Chun Zhang at the University of Wisconsin-Madison Waisman Center are utilizing stem cells in a pre-clinical trial to determine the role of human astrocytes in neurodegenerative diseases such as ALS, Huntington’s disease, and Rhett Syndrome. The team found that, upon integration into the central nervous system, stem cell-derived astrocytes from patients with ALS replace the astrocytes of the host while disrupting motor function, as though the host also had ALS.