Male offspring of pregnant women may be at risk of certain brain disorders that are associated with autism and schizophrenia, due to the woman's hyper immune system.
According to researchers at the Johns Hopkins University School of Medicine, a part of the hippocampus is usually smaller for male offspring of women who were exposed to an overactive immune system in the womb. The hippocampus is responsible for regulating memory and spatial navigation.
The team of researchers, led by Irina Burd, said that fetal mice - particularly males - show symptoms of brain damage which leads into adulthood in the event they are exposed to a maternal immune system that is "kicked into high gear by a serious infection or other malady" in the womb.
"Our research suggests that in mice, males may be more vulnerable to the effects of maternal inflammation than females, and the impact may be life long," said Burd, M.D., Ph.D., an assistant professor of gynecology/obstetrics and neurology at the Johns Hopkins University School of Medicine, said. "Now we wonder if this could explain why more males have diseases such as autism and schizophrenia, which appear to have neurobiological causes."
The study has been published in the online journal Brain, Behavior and Immunity and suggests that certain neurological diseases in humans can similarly be "rooted in prenatal exposure to inflammatory immune responses."
The research also revealed that the males had fewer nerve cells in their brains. Moreover, a type of immune cell which should not be present and is potentially dangerous was there in their brain.
Researchers tried to imitate the effects of a maternal infection or other conditions that lead to inflammation in an expecting mother. To study what happens to the brains of the offspring as they evolve into adults, Burd and her team used a mouse study model an checked if the effects persisted long term.
"One group of pregnant mice got saline injections into the womb, while another group got injections of lipopolysaccharide (LPS), a toxin meant to generate the kind of inflammatory effects of E. coli bacteria without the presence of the germ itself," per the release. "Soon after birth, the LPS group showed poor motor skills and behavioral issues such as hyperactivity. At 60 days post-weaning - the equivalent of mouse adulthood - the LPS mice could walk well, but were still hyperactive, suggesting the motor problems had resolved, possibly through some type of rewiring of the brain, but the behavioral problems had not."
However, all this time, some sort of activity was still on in their brains.
Per Burd, chronic inflammation could play a pivotal role in keeping the hippocampus small. However, the question as to why males and females respond differently to the same "insult in utero" remains a mystery.