Babies, bugs and brains: How the early microbiome associates with infant brain and behavior development

Relationships of Personality Traits With the Taxonomic Composition of the Gut Microbiome Among Psychiatric Inpatients

OBJECTIVE

Through the brain-gut-microbiome axis, myriad psychological functions that affect behavior share a dynamic, bidirectional relationship with the intestinal microbiome. Little is known about the relationship between personality-a stable construct that influences social- and health-related behaviors-and the bacterial ecosystem. The authors of this exploratory study examined the relationship between general and maladaptive personality traits and the composition of the gut microbiome.

METHODS

In total, 105 psychiatric inpatients provided clinical data and fecal samples. Personality traits were measured with the five-factor model of personality, the Structured Clinical Interview for DSM-IV Axis II Personality Disorders, and the Personality Inventory for DSM-5; 16S ribosomal DNA sequencing and whole-genome shotgun sequencing methods were used on fecal samples. Machine learning (ML) was used to identify personality traits associated with bacterial variability and specific taxa.

RESULTS

Supervised ML techniques were used to classify traits of social detachment (maximum area under the receiver operating characteristic curve [AUROC]=0.944, R2>0.20), perceptual disturbance (maximum AUROC=0.763, R2=0.301), and hoarding behaviors (maximum AUROC=0.722) by using limited sets of discriminant bacterial species or genera. Established bacterial genera associated with psychosis (e.g., Peptococcus and Coprococcus) were associated with traits of perceptual disturbance. Hoarding behaviors were associated with a defined gut microbial composition that included Streptococcus, a known contributor to the development of pediatric autoimmune neuropsychiatric disorders.

CONCLUSIONS

Observations from this study are consistent with recent findings demonstrating person-to-person interactions as a mode of gut microbiome transmission. This study adds to the emerging literature on the intricate connections between brain and gut function, expanding the interdisciplinary field of psychiatric microbiology.

Evaluation of Faecal Microbiota Following Probiotics in Infants of Mothers with Gestational Diabetes Mellitus Trial: Protocol for Double-Blind Placebo-Controlled Randomized Trial

(1) Background: The incidence of gestational diabetes mellitus (GDM) is rising globally. The current evidence indicates that GDM, especially in conjunction with maternal overweight, can alter the composition of infants' gut microbiota, potentially increasing the risk of inflammatory diseases, metabolic disorders, and neurodevelopmental issues later in life. Probiotic supplantation early in life might establish eubiosis and mitigate future complications. To best of our knowledge, no study has evaluated the effects of probiotics on gut dysbiosis in the infants of mothers with GDM. (2) Methods: This study will be a single-centre, double-blind, randomized, placebo-controlled trial enrolling sixty neonates born after 35 weeks of gestation to mothers with GDM. The participants will be randomly assigned to receive either a triple-strain probiotic or a placebo for four months. The primary objective is to assess the effectiveness of probiotic supplementation in correcting gut dysbiosis in the infants of mothers with GDM at four months of age. Faecal microbiome composition shall be estimated using 16SrRNA and shotgun sequencing. The secondary outcomes will include the quantification of faecal short-chain fatty acids at birth and at four months, as well as growth and developmental assessments at four, twelve, and twenty-four months. (3) Trial registration: This trial protocol is registered (ACTRN12624000930583p) in the Australian Clinical Trials registry (ANZCTR).

The neonatal gut microbiota: A role in the encephalopathy of prematurity

Preterm birth correlates with brain dysmaturation and neurocognitive impairment. The gut microbiome associates with behavioral outcomes in typical development, but its relationship with neurodevelopment in preterm infants is unknown. We characterize fecal microbiome in a cohort of 147 neonates enriched for very preterm birth using 16S-based and shotgun metagenomic sequencing. Delivery mode strongly correlates with the preterm microbiome shortly after birth. Low birth gestational age, infant sex assigned at birth, and antibiotics associate with microbiome composition at neonatal intensive care unit discharge. We integrate these data with term-equivalent structural and diffusion brain MRI. Bacterial community composition associates with MRI features of encephalopathy of prematurity. Particularly, abundances of Escherichia coli and Klebsiella spp. correlate with microstructural parameters in deep and cortical gray matter. Metagenome functional capacity analyses suggest that these bacteria may interact with brain microstructure via tryptophan and propionate metabolism. This study indicates that the gut microbiome associates with brain development following preterm birth.

Role of Human Milk Microbiota in Infant Neurodevelopment: Mechanisms and Clinical Implications

BACKGROUND

Human milk (HM) is recognized as an ideal source of nutrition for newborns; as a result, its multiple bioactive molecules can support the growth of healthy newborns and reduce the risk of mortality and diseases such as asthma, respiratory infections, diabetes (type 1 and 2), and gastrointestinal disorders such as ulcerative colitis and Crohn's disease. Furthermore, it can reduce the severity of necrotizing enterocolitis (NEC) in preterm infants. Moreover, human milk oligosaccharides (HMOs) present in breast milk show an immunomodulatory, prebiotic, and neurodevelopmental effect that supports the microbiota-gut-brain axis.

MATERIAL AND METHODS

This study examined the state-of-the-art research, using keywords such as "breastfeeding", "human milk oligosaccharides", "microbiota-gut-brain axis", "infants", and "malnutrition". The literature review was conducted by selecting articles between 2013 and 2024, as the most recent ones. The databases used were Web Science, PubMed, and Scopus.

RESULTS

We found multiple studies examining the composition of HM and infant formula (IF). However, further longitudinal studies and randomized control trials (RCTs) are needed to better understand the clinical outcomes that bioactive components exert on healthy and hospitalized children and how, in conditions of malnutrition, it is necessary to support the growth of the newborn.

CONCLUSIONS

In this review, we affirm the importance of human milk and, through it, the modulation of the microbiota and the neuroprotective role in newborns, determining the health of the following years of life.

Microbiome and its impact on fetal and neonatal brain development: current opinion in pediatrics

PURPOSE OF REVIEW

Emerging evidence suggests that the gut microbiota and its metabolites regulate neurodevelopment and cognitive functioning via a bi-directional communication system known as the microbiota-gut-brain axis (MGBA).

RECENT FINDINGS

The MGBA influences brain development and function via the hypothalamic-pituitary axis, the vagal nerve, immune signaling, bacterial production of neurotransmitters, and microbial metabolites like short-chain fatty acids, tryptophan derivatives, and bile acids. Animal studies show fetal neurodevelopment is mediated by maternal microbiota derivatives, immune activation, and diet. Furthermore, manipulation of the microbiota during critical windows of development, like antibiotic exposure and fecal microbiota transplantation, can affect cognitive functioning and behavior in mice. Evidence from human studies, particularly in preterm infants, also suggests that a disrupted gut microbiota colonization may negatively affect neurodevelopment. Early microbial signatures were linked to favorable and adverse neurodevelopmental outcomes.

SUMMARY

The link between the gut microbiota and the brain is evident. Future studies, including experimental studies, larger participant cohort studies with longitudinal analyses of microbes, their metabolites, and neurotransmitters, and randomized controlled trials are warranted to further elucidate the mechanisms of the MGBA. Identification of early, predictive microbial markers could pave the way for the development of novel early microbiota-based intervention strategies, such as targeted probiotics, and vaginal or fecal microbiota transplantation, aimed at improving infant neurodevelopment.