The consequences of early parental separation on gut bacteria and brain function in human children and adolescents.

• In Event: 3-170 - The Microbiome at the Interface of Development and Health

Integrative Statement

Introduction. Separation from caregivers in infancy and early childhood is a serious deviation from species expectations, representing a survival threat to the developing individual. In studies on rodents and monkeys, such early caregiver separations are associated with a range of adverse emotional and physical health consequences, including increased anxiety (Daniels et al., 2004), as well functional gastrointestinal (GI) complaints, such as irritable bowel syndrome (Ren et al., 2007). Moreover, evidence implicating GI bacteria (i.e., the microbiome) in such mental and physical health outcomes is accumulating (O’Mahoney et al., 2011; Bailey & Coe, 1999). In humans, studies performed in adults agree that early caregiving adversity is associated with increased risk for both anxiety (Kessler et al., 2010) and functional GI complaints (Bradford et al., 2012), and circumstantial evidence suggests that the GI microbiome may also be involved (Stern & Brenner, 2018). While these associations are intriguing, understanding the developmental pathways that lead to these adult outcomes is essential for adversity prevention and treatment, and is currently underexplored in humans. In the current series of studies, we took a developmental focus to examine how a time-limited form of early adversity (parental deprivation, followed by adoption) was associated with anxiety neurobiology, functional GI complaints, and the GI microbiome.
Hypotheses. It was hypothesized that early life exposure to parental deprivation would be associated with elevated anxiety symptoms, increased functional GI complaints, and changes in the GI microbiome.
Study population. Children and adolescents were enrolled in the study when they were between 4-17 years of age. Approximately half of the children had a history of parental deprivation, followed by international or domestic adoption. The remaining children had always remained with their biological parents.
Methods. Children and adolescents came into the research lab with their parents on two different days. On the first day, parents and their child/adolescent answered questionnaires about emotional functioning and GI health, and the parent was interviewed about their child’s/adolescent’s mental health using the semi-structured Kiddie Schedule for Affective Disorders interview. On the second day, children/adolescents received a functional magnetic resonance imaging (fMRI) scan and were given a kit to collect a stool sample in the weeks after the MRI scan. Children returned their collected stool to the lab via registered post. Bacteria in stool were sequenced using 16s rRNA to reveal taxonomic composition of the GI microbiome.
Results. In a pilot study, prior caregiving adversity was associated with increased anxiety symptoms, as well as increased GI complaints. The composition of the GI microbiome was also different between children/adolescents according to caregiving history, with the youth exposed to earlier parental deprivation having fewer bacterial groups represented in the stool than non-parentally deprived youth (alpha-diversity), and the bacterial communities between the two groups did not exhibit a great degree of overlap (beta-diversity). The current talk will present those pilot data, as well as the same analyses on the recently completed study in the larger population of youth.

Author

• Bridget Callaghan, Columbia
  Presenting Author