THE blood-brain barrier shields the central nervous system, which comprises the brain and spinal cord, from the immune system.
In a new study, researchers have hypothesized that if this barrier is compromised, it could cause inflammation in the brain, which may, in turn, trigger schizophrenia.
To investigate this relationship, they used cells isolated from healthy individuals and from people with a rare genetic disorder that increases the risk of schizophrenia.
The blood-brain barriers derived from cells of the latter group were more ‘leaky’ and produced more inflammatory molecules.
Schizophrenia is a psychiatric condition that is characterized by “positive” symptoms, such as hallucinations and delusions, and “negative” symptoms, such as social withdrawal and apathy.
For almost a century, scientists have speculated about a possible link between the immune system and schizophrenia.
Several lines of evidenceTrusted Source suggest that the inflammation provoked by a viral infection, either before birth or during childhood, could trigger the condition in adulthood.
Some studiesTrusted Source have also found changes in the blood-brain barriers of people with schizophrenia.
The blood-brain barrierTrusted Source comprises the tightly packed layer of cells that line the blood vessels in the brain and spinal cord. It prevents blood-borne immune cells from gaining entry to the central nervous system.
This is sometimes known as conferring “immune privilege” on the brain — in other words, protecting it from harmful inflammation.
Researchers at the University of Pennsylvania’s School of Veterinary Medicine in Philadelphia wondered whether a compromised blood-brain barrier in people with a rare genetic disorder known as DiGeorge syndrome or 22qDS, a genetic deletion syndrome, could be responsible for their increased risk of schizophrenia.
People born with the condition have a 1 in 4 risk of developing schizophrenia later in life.
This is compared with an overall risk of schizophrenia of around 1 in 100 in the wider adult population.