Human brain tissue has been transplanted into the brain of rats to pave the way to treat major brain injuries.
A groundbreaking study by neurosurgeons showed that ‘human brain organoids’ or sesame seed-sized balls of neurons were able to integrate into rats’ brains, linking up with their blood supplies and communicating with the rat neurons.
This could eventually lead to doctors being able to grow blobs of brain tissue from a patient’s own cells in the lab and use them to repair brain injuries caused by stroke or trauma.
This is the first time that lab-grown brain tissue has been successfully implanted into an injury site to repair an adult brain, suggesting there could be future clinical applications.
‘This is incredibly exciting to me as a physician,’ said Isaac Chen, a physician and assistant professor of neurosurgery at the University of Pennsylvania.
The study shows that when cultivated in the right conditions, neurons begin to form tiny brain-like structures.
This allows scientists to investigate developmental conditions such as autism and a wide range of basic neuroscience questions.
The researchers grew human brain organoids in a dish until they were about 1.5mm in diameter.
The tissues were then transplanted into the brains of adult rats that had sustained injuries to their visual cortex.
Within three months, the grafted organoids had integrated with their host’s brain, hooking up with the blood supply, expanding to several times the initial volume and sending out projections that linked up with the rat’s neurons, according to the study published in Cell Stem Cell.
‘We were not expecting to see this degree of functional integration so early.’ said Chen.
While it was unclear how well the rats’ vision was improved, tests showed that the human neurons fired electrical signals when the rats were exposed to flashing lights.
Chen said that this supported the idea that the brain could absorb organoids and use them to rebuild itself after an injury.
‘By rationally introducing these engineered processing units to specific areas of the injured brain, we think that the increased computational capacity of those areas would result in sufficient restoration of brain networks to restore neurological function,’ said Chen.
In theory, personalised brain organoids could be created in the lab from a patient’s own cells, although Chen predicted that clinical applications would be at least five to 10 years away.
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