The brain relies on a constant composition of its environment for proper development and function, maintained by the ‘brain-barriers’. These barriers also constitute an interface of communication between peripheral cues and the brain. One such source of peripheral signals is the gut-microbiota - an ecosystem of trillions of microorganisms that populate our guts. Though alterations in microbiota are associated with several neurodevelopmental disorders such as autism spectrum disorder (ASD), schizophrenia and attention deficit hyperactivity disorder (ADHD), the exact mechanisms of communication are largely unknown.
The NeuroVascOme project asked whether this microbiota regulates the barriers in the developing brain through compounds that are produced by our gut microbes and reach the circulating blood, and consequently affect brain microenvironment and function.
Understanding this is particularly important given the multiple factors that are known to disrupt our microbiota, such as antibiotics, stress and birth by Caesarean section (C-section). C-section bypasses the birth canal, where the initial microbiota seeding happens, through vertical transmission of vaginal and faecal maternal microbiota to the new born. Moreover, this intervention is highly relevant in our society; according to recent research from World Health Organisation (WHO), C-section use continues to rise globally, now accounting for more than 1 in 5 (21%) of all childbirths. While C-section can be an essential and lifesaving surgery, it can put women and babies at unnecessary risk of short- and long-term health problems if performed when there is not medical need. One of the known risks of C-section, as mentioned above, is the disruption of the vertical transmission of maternal vaginal and faecal microbes to the new born. Moreover, a recent study showed that mice born by C-section display behavioural and cognitive deficits, that can be rescued by gut-microbiota based interventions, such as administration of pre- or probiotics.
Overall, we know little about the impact of gut microbiota disruption on our brains, especially in early life, when the brain is particularly vulnerable. Understanding how C-section can impact the developing brain through the disruption of the early-life microbiome, is essential for developing future microbiota-based strategies to enhance the microbiota composition in this vulnerable population.
