A postmortem analysis of male patients revealed differences in the cellular composition of the brain in those who died by suicide compared with those who died suddenly from other causes, according to a study published online in Frontiers in Psychiatry.
The men who died by suicide had depression, while the men who died by other means had no psychiatric disorders. Naguib Mechawar, PhD, and colleagues at McGill University, Montreal, Canada, conducted the postmortem analysis to investigate the potential role astrocytes play in major depressive disorder.
“We found a reduced number of astrocytes, highlighted by staining the protein vimentin, in many regions of the brain in depressed adults,” said Dr. Mechawar, a senior author of the study and a psychiatry professor at McGill. “These star-shaped cells are important because they support the optimal function of brain neurons. Our findings confirm and extend previous research implicating astrocytes in the pathology of depression.”
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“We analyzed the astrocytes in the brain by staining specific proteins found in their structure—vimentin and glial fibrillary acidic protein,” researcher Liam O’Leary, a PhD student, explained. “Vimentin staining has not been used before in this context, but it provides a clear, complete, and unprecedented view of the entire microscopic structure of these cells.”
Researchers found the number of astrocytes were globally reduced in men who died by suicide compared with those who died by other causes. However, the structure of astrocytes between the 2 groups were similar.
Plans call for similar investigations in women, researchers said, since the neurobiology of depression is known to differ between the sexes. Nevertheless, the findings offer hope for the development of targeted treatment options.
“Our study provides a strong rationale for developing drugs that counteract the apparent loss of astrocytes in depression,” O’Leary said. “No antidepressants have yet been developed to target these cells directly, although the leading theory for the rapid antidepressant action of ketamine, a relatively new treatment option, is that it corrects for astrocyte abnormality.”
—Jolynn Tumolo
References
O'Leary LA, Belliveau C, Davoli MA, et al. Widespread decrease of cerebral vimentin-immunoreactive astrocytes in depressed suicides. Frontiers in Psychiatry. 2021;12:640963.