Schizophrenia May Be Diagnosed By Testing Nerve Cells From The Nose
A report on the study is due to be published in the July 2013 print issue of Neurobiology of Disease, a version of which is already available to view online.
At present, schizophrenia can only be confirmed physiologically through sampling the brain during an autopsy. So diagnosis relies on psychiatrists giving patients batteries of psychological tests, and interviewing patients, their families and their friends.
In their study paper, Noam Shomron of TAU's Sackler Faculty of Medicine, and colleagues, describe how they developed a potential way of diagnosing schizophrenia by testing microRNA molecules in neurons removed from the nose via a simple biopsy.
Shomron says in a statement released this week that he and his colleagues anticipate this could lead to a "more sure-fire" way of diagnosing schizophrenia than ever before. It could also lead to earlier detection of the disease, which could vastly improve treatment.
Before this study, the only way to test for biomarkers for schizophrenia was to sample cells taken from the brain, which could only be done after death.
But then Shomron and colleagues had a hunch that perhaps olfactory neurons located in the upper part of the inner nose might also offer some biomarkers.
For their study, they collected olfactory neurons from patients diagnosed with schizophrenia and a control group of individuals without the disease, and ran them through high-throughput sequencers that can scan the microRNA molecules in the cells. MicroRNA molecules don't code for proteins but they help to regulate gene expression.
The results showed that nose neurons from the schizophrenia patients had much higher levels of one particular microRNA (called miR-382) than those taken from the unaffected controls, as Shomron explains:
"We were able to narrow down the microRNA to a differentially expressed set, and from there down to a specific microRNA which is elevated in individuals with the disease compared to healthy individuals."
After some more research, the team found that this particular microRNA molecule regulates the expression of genes that are involved in the creation of neurons.
A clinical test based on this method would involve taking a small biopsy using a local anesthetic. This could easily be done as an outpatient procedure, says Shomron.
And with today's microRNA sequencers, the profiling could be ready in hours.
The researchers say their method could lead to a simple, quick and accurate test for a complicated illness.
Although Shomron has high hopes, he says there are still some questions to answer with further studies before we can be sure such a test is viable.
For instance, it is not clear whether the changes to microRNA expression begin before schizophrenic symptoms show, or after. If it happens before, or near the beginning of the timeline of the disease, then the test would be an invaluable diagnostic tool because it would help early detection, which would mean earlier treatment.
It could even, perhaps, increase the chances of delaying symptoms. For instance, in people with a family history of schizophrenia, such a test could show whether they also have it.
And while such early warning doesn't mean a cure is imminent, it does help patient and doctor prepare for what may lie in store.
The study also shows there could be potential for using nose neurons as surrogates for brain neurons in other types of research.
In another recently published study, researchers from Columbia University Medical Center suggest that an excess of the brain neurotransmitter glutamate may trigger psychosis in people who are at risk for schizophrenia.
Written by Catharine Paddock PhD