Prenatal stress enhances postnatal plasticity: The role of microbiota

Behavioral Development of Pediatric Exotic Pets and Practical Applications

The discovery of epigenetics and the interaction between genes and the environment have moved our understanding of how animal behavior develops from gestation to adulthood, and even throughout generations, to a new level. Studying the natural biology of exotic pets is key to providing them with a rich social and physical environment that will encourage species-specific behaviors. Combining parent-raising with appropriately timed human handling is likely to result in individuals with more resilience to stress. Using operant conditioning techniques early in life to train the animals' basic behaviors gives them control over their environment, empowering them through their social interactions.

Development programming: Stress during gestation alters offspring development in sheep

Inappropriate management practices of domestic animals during pregnancy can be potential stressors, resulting in complex behavioural, physiological and neurological consequences in the developing offspring. Some of these consequences can last into adulthood or propagate to subsequent generations. We systematically summarized the results of different experimental patterns using artificially increased maternal glucocorticoid levels or prenatal maternal physiological stress paradigms, mediators between prenatal maternal stress (PMS) and programming effects in the offspring and the effects of PMS on offspring phenotypes in sheep. PMS can impair birthweight, regulate the development of the hypothalamic-pituitary-adrenal axis, modify behavioural patterns and cognitive abilities and alter gene expression and brain morphology in offspring. Further research should focus on the effects of programming on gene expression, immune function, gut microbiome, sex-specific effects and maternal behaviour of offspring, especially comparative studies of gestational periods when PMS is applied, continual studies of programming effects on offspring and treatment strategies that effectively reverse the detrimental programming effects of prenatal stress.

Prenatal programming of environmental sensitivity

According to several theories, people differ in their sensitivity to environmental influences with some more susceptible than others to both supportive and adverse contextual conditions. Such differences in environmental sensitivity have a genetic basis but are also shaped by environmental factors. Herein we narratively build on our previous work proposing that prenatal experiences contribute to the development of environmental sensitivity. This hypothesis of prenatal programming of postnatal plasticity has considerable empirical support. After presenting illustrative animal and human evidence consistent with this claim, we discuss a range of biological mechanisms likely involved in the pathway from prenatal stress exposure to postnatal environmental sensitivity. We also consider work suggesting that genetic differences, gender, as well as the timing, duration and intensity of prenatal exposures may moderate the effects of prenatal programming on postnatal environmental susceptibility or sensitivity. Before concluding, we highlight "unknowns in the prenatal programming of environmental sensitivity" and their practical implications. Ultimately, we conclude that prenatal stress does not necessarily predispose individuals to problematical development, but rather increases sensitivity to both adverse and supportive postnatal contexts. Thus, prenatal stress may actually foster positive development if paired with supportive and caring postnatal environments.

Maternal stress and the maternal microbiome have sex-specific effects on offspring development and aggressive behavior in Siberian hamsters (Phodopus sungorus)

The gut microbiome, a community of commensal, symbiotic and pathogenic bacteria, fungi, and viruses, interacts with many physiological systems to affect behavior. Prenatal experiences, including exposure to maternal stress and different maternal microbiomes, are important sources of organismal variation that can affect offspring development. These physiological systems do not act in isolation and can have long-term effects on offspring development and behavior. Here we investigated the interactive effects of maternal stress and manipulations of the maternal microbiome on offspring development and social behavior using Siberian hamsters, Phodopus sungorus. We exposed pregnant females to either a social stressor, antibiotics, both the social stressor and antibiotics, or no treatment (i.e., control) over the duration of their pregnancy and quantified male and female offspring growth, gut microbiome composition and diversity, stress-induced cortisol concentrations, and social behavior. Maternal antibiotic exposure altered the gut microbial communities of male and female offspring. Maternal treatment also had sex-specific effects on aspects of offspring development and aggressive behavior. Female offspring produced by stressed mothers were more aggressive than other female offspring. Female, but not male, offspring produced by mothers exposed to the combined treatment displayed low levels of aggression, suggesting that alteration of the maternal microbiome attenuated the effects of prenatal stress in a sex-specific manner. Maternal treatment did not affect non-aggressive behavior in offspring. Collectively, our study offers insight into how maternal systems can interact to affect offspring in sex-specific ways and highlights the important role of the maternal microbiome in mediating offspring development and behavior.

Prenatal food insecurity post Hurricane Maria is associated with decreased Veillonella in the infant gut

BACKGROUND

Hurricane Maria struck Puerto Rico on 20 September 2017 causing catastrophic devastation. Prolonged shortage of food had been a substantial challenge to the residents after Maria. Experiencing food insecurity in utero has been associated with negative health outcomes later in life. We aim to examine whether there is any alteration in the infant gut microbiome that is associated with prenatal food insecurity.

METHODS

We established a cohort of infants aged 2-6 months who were exposed in utero to Hurricane Maria near San Juan, Puerto Rico and examined the gut microbiota (n = 29) using 16S ribosomal RNA gene sequencing.

RESULTS

Among the enrolled infants, 30% of their mothers experienced "post-Maria poor access to food" for at least 1 month during pregnancy. The relative abundance of gut Veillonella spp. is significantly decreased among infants who experienced prenatal food insecurity, compared to those who did not (adjusted p = 0.025). There is no significant difference observed by prenatal food insecurity at the microbial community level in this cohort.

CONCLUSIONS

Our finding indicated that infants who experienced prenatal food insecurity post hurricane harbor microbial alternations of specific bacterial taxa, which may further influence the microbial maturation and place the individual at a high-risk health trajectory.

IMPACT

We identified that in utero exposure to food insecurity post Hurricane Maria is associated with decreased abundance of Veillonella in the infant gut. Our findings indicated that infants who experienced prenatal food insecurity post hurricane may harbor alterations of specific bacterial taxa in their gut microbiota. This study showed the association between prenatal adverse exposure and alterations of gut microbiome early in life in the context of an extreme event. This study provided insights into the mechanisms underlying prenatal adverse exposure and increased disease risks later in life. Our findings will potentially raise awareness of the negative impact of extreme climate events on the unborn.

Moving the dial on prenatal stress mechanisms of neurodevelopmental vulnerability to mental health problems: A personalized prevention proof of concept

Prenatal stress exposure increases vulnerability to virtually all forms of psychopathology. Based on this robust evidence base, we propose a "Mental Health, Earlier" paradigm shift for prenatal stress research, which moves from the documentation of stress-related outcomes to their prevention, with a focus on infant neurodevelopmental indicators of vulnerability to subsequent mental health problems. Achieving this requires an expansive team science approach. As an exemplar, we introduce the Promoting Healthy Brain Project (PHBP), a randomized trial testing the impact of the Wellness-4-2 personalized prenatal stress-reduction intervention on stress-related alterations in infant neurodevelopmental trajectories in the first year of life. Wellness-4-2 utilizes bio-integrated stress monitoring for just-in-time adaptive intervention. We highlight unique challenges and opportunities this novel team science approach presents in synergizing expertise across predictive analytics, bioengineering, health information technology, prevention science, maternal-fetal medicine, neonatology, pediatrics, and neurodevelopmental science. We discuss how innovations across many areas of study facilitate this personalized preventive approach, using developmentally sensitive brain and behavioral methods to investigate whether altering children's adverse gestational exposures, i.e., maternal stress in the womb, can improve their mental health outlooks. In so doing, we seek to propel developmental SEED research towards preventive applications with the potential to reduce the pernicious effect of prenatal stress on neurodevelopment, mental health, and wellbeing.

Sensitive phases in the development of rodent social behavior

Here, we summarize recent advances on how environmental influences during sensitive phases alter the social behavioral phenotype of rodents later in life. Current studies support the view that the prenatal, early postnatal and adolescent periods of life can be regarded as sensitive phases. Environmental cues acting on the organism during these phases have a wide variety of effects on adult social behavior. One pattern that emerges across species and sensitive phases is that adversity tends to reduce social interactions and particularly affiliative social behavior. Concerning underlying mechanisms, various hormones can be involved; however, glucocorticoids frequently serve as the signal instigating plasticity. There is also increasing appreciation of non-endocrine mechanisms, specifically epigenetics and the microbiome. Concerning function, some evidence exists that sensitive phase outcomes adjust the individual's social phenotype to the nature of the social environment to be present during adulthood and breeding, though additional empirical support is still needed.

External environment and internal state in relation to life-history behavioural profiles of adolescents in nine countries

The external environment has traditionally been considered as the primary driver of animal life history (LH). Recent research suggests that animals' internal state is also involved, especially in forming LH behavioural phenotypes. The present study investigated how these two factors interact in formulating LH in humans. Based on a longitudinal sample of 1223 adolescents in nine countries, the results show that harsh and unpredictable environments and adverse internal states in childhood are each uniquely associated with fast LH behavioural profiles consisting of aggression, impulsivity, and risk-taking in adolescence. The external environment and internal state each strengthened the LH association of the other, but overall the external environment was more predictive of LH than was the internal state. These findings suggest that individuals rely on a multitude and consistency of sensory information in more decisively calibrating LH and behavioural strategies.

Impact of gut microbiota on neurogenesis and neurological diseases during infancy

The first years of life constitute a crucial period for neurodevelopment and a window of opportunity to develop new strategies to prevent neurological and mental diseases. Different studies have shown the influence of gut bacteria in neurogenesis and a functional relationship between gut microbiota and the brain, known as 'gut-brain axis', in which the intestinal microbiota is proposed to play a key role in neurophysiological processes. It has been observed that certain microbiome metabolites could be related to the development of neurological disorders through mechanisms still unknown. Then, more studies are needed to broaden the knowledge regarding the relationship between the Central Nervous System and the gastrointestinal tract, which could help to develop new preventive and treatment protocols.