Maternal infections during pregnancy can impair fetal brain development and lead to cognitive problems, according to a new Danish study conducted on mice. The researchers believe these impairments help explain why infections during pregnancy have been linked to psychiatric disorders, such as schizophrenia and autism.
The findings are published in the journal Molecular Psychiatry.
A pregnant mother’s health is vital for fetal brain development. Many factors play key roles for healthy brain development, including nutrition, stress, hormonal balance and the mother’s immune system.
It has been observed in both humans and animals that severe infections in the pregnant mother are a risk factor for developing psychiatric disorders such as schizophrenia and autism spectrum disorders later in life for the offspring.
“The connection has been made in animal studies and clinical observation studies. However, this is the first time that we show how infections during pregnancy affect brain development and can lead to cognitive impairment,” said Dr. Konstantin Khodosevich, associate professor in the Biotech Research and Innovation Centre (BRIC).
“While many factors have been hypothesised or indicated, it is important that we show the steps of neuronal development that are actually affected.”
For the study, the researchers examined the development of neurons in mice. The mother’s immune response to infection had an effect stretching from stem cells and precursor cells to neuronal cells leading to profound disruption in their brain development.
More specifically, the development of cortical GABAergic interneurons — the key neurons that provide inhibition in the brain — was impaired.
The effect was immediate and cascaded to dramatic long-lasting impairments, thus resulting in multiple “hits” from the time neurons were born to the time they matured.
Furthermore, the researchers also concluded that the newborn mice showed symptoms resembling those from human psychiatric disorders including decreased startle response, altered social interactions and cognitive decline.
“There are big technological and ethical issues about studying this in humans because of the vulnerability of pregnant women. That is why we study how the mechanisms work in mice. Psychiatric disorders are really complex and for some of them, we are still only guessing how they arise. We really want to contribute to the scientific understanding of these diseases,” Khodosevich said.
The study also shed light on the effects of infections at different times during pregnancy. Depending on the time of infection, different precursor cells and thus different neurons were impacted.
This means that the timing of infection is very important and can lead to varying outcomes based on which stage of brain development is affected.