A study of newborn piglets found that influenza A infection disrupted both nasal and gut microbiomes and triggered potentially harmful changes in gene activity in the hippocampus a key brain region for learning and memory. Vaccinating pregnant sows appeared to provide some protection against these effects in their offspring.

The CDC notes that infants under six months are at the highest risk for hospitalization due to influenza A infection. With immature immune systems newborns face increased risks of complications including brain inflammation which can sometimes be fatal or impair brain development in survivors.

Infants infected with influenza A within their first six months face a higher risk of long-term complications such as diabetes asthma allergies and cognitive impairments. According to Ying Fang professor of pathobiology at the University of Illinois Urbana-Champaign vaccination during pregnancy is the most effective way to protect newborns from these outcomes. Fang led the research alongside fellow pathobiology professor Christopher Gaulke.

Fang, a microbiologist specializing in pathogenic viruses is developing a new influenza A vaccine a version of which was tested in pregnant sows for this study. Gaulke also a microbiologist focuses on how the microbiome influences health and disease.

While prior studies have connected disease-driven gut microbiome changes to shifts in brain gene expression most of this research has centered on adults the team noted.We are the first to use a neonatal piglet model to explore how the microbiome interacts with brain gene function Fang said. She noted that pigs serve as an excellent model for studying human infections due to their physiological similarities to humans and their susceptibility to many of the same zoonotic viruses.

Many studies have linked the microbiome to healthy brain development throughout life especially in early stages Gaulke said. The microbiome seems to help establish proper brain function and disruptions in animal models can lead to negative outcomes including neurocognitive issues.

In this new study the researchers compared changes in microbiomes and hippocampal gene expression in piglets born to vaccinated and unvaccinated sows after influenza A infection. A third control group consisted of uninfected piglets whose mothers received a placebo vaccine during pregnancy.

They found clear differences in gut and nasal microbiota as well as hippocampal gene expression following infection. While beneficial microbes in the nose and gut increased in all groups post-infection the rise was smaller in piglets from unvaccinated sows. These piglets also showed greater increases in potentially harmful microbes especially in the nasal cavity changes that closely mirrored negative shifts in hippocampal gene expression.

We knew that influenza during pregnancy or early life can harm brain development Gaulke said. And we knew that the microbiome plays a role in early brain function and that influenza affects both respiratory and gut microbiota. But no one had connected all these factors in a neonatal model. Our study examined how the microbiome may influence hippocampal function during influenza infection.

The results suggest that maternal vaccination can lessen the damaging effects of influenza infection on both the microbiome and hippocampal development in offspring. The team notes that further research is needed to clarify the mechanisms behind these changes and their impact on brain health.

Source: https://news.illinois.edu/study-links-influenza-a-viral-infection-to-microbiome-brain-gene-expression-changes/