By using genetic material from human blood and lab-grown brain cells, a team led by Johns Hopkins’ Sarven Sabunciyan has made progress in developing a blood test to identify disease-associated changes in the brain specifically linked to postpartum depression and other psychiatric and neurological disorders.

“This is very exciting, because right now, there isn’t a blood marker for disorders affecting the brain. Essentially, these conditions are diagnosed by clinical interviews between patients and providers,” says Lena Smirnova, an assistant professor at the Johns Hopkins Bloomberg School of Public Health and co-author of the research, published in Molecular Psychiatry.

The scientists focused on identifying the “footprints” of brain cell-derived mRNAs in blood circulating outside the brain. These blood extracellular vesicles carry brain-specific pieces of genetic material that potentially allow researchers to detect disease-associated changes in gene activity inside the brain. Extracellular vesicles (EVs), fatty sacs of genetic material essential to communication among cells, carry messenger RNA (mRNA) and are released by every tissue in the body, including the brain.

The new research was inspired by results of an earlier study led by Sabunciyan, an assistant professor of pediatrics, which discovered EV communication is altered in pregnant women who go on to develop postpartum depression after giving birth.

The goal, Sabunciyan says, is to develop a simple blood test to detect changes such as higher or lower levels of blood EV mRNAs directly linked to changes in the brain associated with mental disorders without having access to the brain itself. Eventually, he adds, the availability of such blood tests could enable detection of early signs of mental health emergencies, such as suicidal behavior, in time to intervene and possibly prevent negative outcomes.