The three magic words to coax human nerve cells to thrive in a laboratory are location, location, location.
Many experiments involve growing human nerve cells in lab petri dishes. A new study involves enlisting some real estate that’s a bit more unusual: the brain of a rat. Clusters of human neurons that are implanted grow big in size and are more complex than their cohorts cultivated in dishes, report researchers in an online edition of Nature.
Furthermore, human cells appear functional, however, in very limited ways. The implanted human cells work in two ways: receive signals from rat cells control behaviour of rats, connections that showcase more substantial integration of transplanted neurons. This is a significant advancement.
Over the last decade, scientists have been creating increasingly complex brain organoids, 3-D clusters of cells obtained from stem cells that grow and imitate the human brain. In fact, these organoids don’t recreate the full complexity of human neurons that develop in an actual brain. But the organoids can be windows into an otherwise puzzling process – human brain development and how it can go inaccurate. Even if not perfect, these models are surrogates for human cells in a way that animals are not. And this is really exciting.
Meanwhile, to push the cells to their full potential, a neuroscientist and his colleagues at the Stanford School of Medicine surgically placed human cerebral organoids in the brains of newborn rats. The human organoids began to grow along with their hosts. Three months later, the organoids were almost nine times of the volume they started with, ultimately making up about a third of one side of the cortex of the host rat, which is the outer layer of the brain.
“It pushes the rat cells aside,” stated the neuroscientist.