Medical researchers have found a way to create functional neurons with nothing but a small vial of human blood and four proteins.
T Cells And Nerve Cells
A team of researchers at the Stanford University School of Medicine devised a new method of transforming special immune cells into functional nerve cells for the central nervous system and the peripheral nervous system.
By adding four special proteins into 1 milliliter of human blood, the team was able to convert the blood cells into neurons, sometimes generating as many as 50,000 new neurons per milliliter of blood. They also found that the method works for both fresh and frozen samples of blood.
The findings are instrumental in conducting deeper research on complex neurological disorders, particularly autism and schizophrenia. The method outlined in this study will allow scientists to examine the neurons of patients by simply requesting for a blood sample.
Details of the study are published in the Proceedings of the National Academy of Sciences.
Transdifferentiation, A Direct Approach
Researchers have been able to convert human skin cells in the past. However, unlike the previous method, the new process allows researchers to directly convert blood cells into neurons, bypassing a state called pluripotency where the skin cells can be converted into any type of tissue.
The process is called transdifferentiation, which has been shown to very successful in converting T cells into neurons.
T cells are highly specialized round-shaped cells that protect the human body from cancers and infections by detecting infected cells and killing them. Neurons, on the other hand, are long, thin cells that carry electrical signals and pass them along to other nerve cells.
Despite the differences between these cells, the researchers found it very easy to transform blood cells into neurons.
"It's kind of shocking to find how easy it is to convert T cells into functional neurons in just a few days," senior author and pathology professor Marius Wernig says. "T cells are very specialized immune cells with a simple round shape, so the rapid transformation is somewhat mind-boggling."
The outcome, however, is not perfect. Although the resulting neurons can carry the basic functions of nerve cells, they still cannot build mature connections with one another.
Limitations Of Previous Methods
Wernig and his team first converted skin cells into nerve cells in 2010, when they successfully transformed skin cells harvested from a mouse into nerve cells. They replicated the same method on human cells and successfully converted skin cells and liver cells.
However, their previous method had limitations, especially for doctors studying neurological disorders. For one, it required them to induce the cells into pluripotency, which takes longer than directly converting blood cells into neurons.
Using skin cells from hundreds of patients is also tedious and expensive, not to mention painful and invasive for the person providing the samples. Blood, on the other hand, is very easy to obtain. Practically every person who walks into a hospital has a blood sample taken.