Scientists have grown miniature human brains in the skulls of mice. (File photo)
In a first, US scientists have grown miniature human brains or human brain organoids, in the skulls of mice, a breakthrough that could boost stem cell research as well as provide insight into neurological disorders such as autism, dementia, and schizophrenia.
Scientists from the Salk Institute grafted human stem-cell-based organoids into a blood-vessel-rich area of the mouse brain.
The grafted human organoids integrated into the host environment, formed both neurons and neuronal support cells called astrocytes, and were surveyed by immune cells.
Significantly, the team saw not only native blood vessels, but vessels with blood flowing through them - a first for organoids, revealed the paper detailed in the journal Nature Biotechnology.
"That was a big accomplishment," lead author Abed AlFattah Mansour, a research associate at Salk, said in a statement.
"We saw infiltration of blood vessels into the organoid and supplying it with blood, which was exciting because it's perhaps the ticket for organoids' long-term survival," Mansour added.
In the study, the team divided each organoid in half before transplantation, and maintained one of the halves in culture so they could directly compare the benefit of both environments.
They found that the cultured halves were filled with dying cells after a few months, while the age-matched organoids in the rodents were healthy.
Human transplantation in animals has been used for decades in brain and other tissues to enhance survival and test for mature function.
But, the new approach can develop more sophisticated organoid models by ensuring they receive sufficient oxygen and other nutrients via transplantation into rodents.
The work could yield insights into the development of cures for brain disorders, speed up the testing of drugs, and even pave the way for someday transplanting healthy populations of human cells into people's brains to replace damaged or dysfunctional tissue, the researchers said.