Prenatal stress, fetal imprinting and immunity

Maternal stress and early-onset colorectal cancer

Early-onset colorectal cancer (EOCRC) is defined as colorectal cancer (CRC) diagnosed before the age of 50. Alarmingly, there has been a significant increase in EOCRC diagnoses' worldwide over the past several decades. Emerging data suggest EOCRCs have distinguishing clinical, pathological, biological and molecular features; and thus, are a fundamentally different subtype of CRCs. Unfortunately, there is no simple explanation for the causes of EOCRC. Scientifically rigorous studies are needed to determine what may be driving the challenging epidemiology of EOCRC. We contend here that a reasonable hypothesis is that prenatal risk factors such as maternal stress and associated sleeping disorders influence offspring epigenetic make-up, and shape immune system and gut health contributing to an increased risk for EOCRC.

Neuroendocrine and immune pathways from pre- and perinatal stress to substance abuse

Early life adversity is a documented risk factor for substance abuse and addiction. The pre- and perinatal period (i.e., from implantation, through pregnancy, to 6 months of age) is a critical period marked by high biological plasticity and vulnerability, making perinatal stress a particularly robust form of adversity. The neuroendocrine and immune systems are key mechanisms implicated in the transmission of addiction risk. We review animal and human studies that provide preliminary evidence for links between perinatal stress, neuroendocrine and immune dysregulation, and risk for substance abuse and addiction. A translational neuroscience perspective is employed to elucidate pre- and perinatally-induced biological mechanisms linked to addiction and discuss implications for prevention and intervention efforts. Significant evidence supports associations between pre- and perinatal stress and dysregulation of the hypothalamic-pituitary-adrenal axis and immune systems as well as links between neuroendocrine/immune functioning and addiction risk. More work is needed to explicitly examine the interplay between pre- and perinatal stress and neuroendocrine/immune disruptions that together heighten substance abuse risk. Future work is needed to fully understand how pre- and perinatal stress induces biological alterations to predispose individuals to higher risk for addiction. Such knowledge will strengthen theoretically-driven and empirically-supported prevention efforts for substance abuse and addiction.

Prenatal stress and enhanced developmental plasticity

Two separate lines of inquiry indicate (a) that prenatal stress is associated with heightened behavioral and physiological reactivity, and (b) that these postnatal phenotypes are associated with increased susceptibility to both positive and negative developmental experiences and environmental exposures. This research considered together raises the intriguing hypothesis first advanced by Pluess and Belsky (Dev Psychopathol 23:29-38, 2011) that prenatal-stress fosters, promotes or "programs" postnatal developmental plasticity. In this paper, we review further evidence consistent with this proposition, including a novel animal study which experimentally manipulated both prenatal stress and postnatal rearing. Directions for future work focused on mechanisms mediating the plasticity-inducing effects of prenatal stress and the moderators of such effects are outlined.

Parents' depression and loneliness during pregnancy and respiratory infections in the offspring: A prospective birth cohort study

Background

An association between maternal prenatal stress and increased rates of respiratory tract infections in the offspring has been described earlier. Data regarding the father’s role is lacking. In this study our aim was to evaluate, whether mothers’ and fathers’ depressive symptoms and loneliness during pregnancy predict higher rates of respiratory tract infections in the offspring.

Methods

In this longitudinal cohort study we gathered information on parental psychological risk during gestational week 20 using the BDI-II and UCLA loneliness scale questionnaires for the parents of 929 children. Loneliness was divided into social and emotional components, the former describing patterns of social isolation and the latter a perceived lack of intimate attachments. Episodes of acute otitis media, physician visits due to respiratory tract infections, and antibiotic consumption relating to respiratory tract infections were documented in the infants, excluding twins, from birth until 10 months of age using study diaries. Analyses were carried out by structural equation modeling, which provides dynamic estimates of covariances.

Results

Maternal depressive symptoms during pregnancy predicted higher rates of acute otitis media in the infant and maternal emotional loneliness predicted higher rates of physician visits. Acute otitis media, physician visits and antibiotic consumption in the infant were slightly less frequent for families who reported social loneliness in the father or mother. Associations remained when taking into account confounders.

Conclusions

Maternal prenatal depression and emotional loneliness predicted a higher burden of respiratory tract infections in the offspring. The protective influence of parental social loneliness on the burden of respiratory tract infections in infants was not in line with our study hypothesis, but could be explained by reduced use of healthcare services in these socially isolated families.

Microglia and the Brain: Complementary Partners in Development and Disease

An explosion of findings driven by powerful new technologies has expanded our understanding of microglia, the resident immune cells of the central nervous system (CNS). This wave of discoveries has fueled a growing interest in the roles that these cells play in the development of the CNS and in the neuropathology of a diverse array of disorders. In this review, we discuss the crucial roles that microglia play in shaping the brain-from their influence on neurons and glia within the developing CNS to their roles in synaptic maturation and brain wiring-as well as some of the obstacles to overcome when assessing their contributions to normal brain development. Furthermore, we examine how normal developmental functions of microglia are perturbed or remerge in neurodevelopmental and neurodegenerative disease.

Newborn infants' hair cortisol levels reflect chronic maternal stress during pregnancy

Cortisol obtained from hair samples represents a retrospective biomarker of chronic stress experienced by the subject in previous months. Although hair cortisol levels have been used to study the relationship between maternal and neonatal stress levels in primates, this has not yet been performed in humans using a longitudinal design and focusing specifically on this association. Therefore, the objective of this study was to determine whether a relationship existed between maternal psychological stress and hair cortisol levels during pregnancy and postpartum, and neonatal hair cortisol levels. The sample consisted of 80 pregnant women and their 80 newborn infants. We conducted a longitudinal assessment of hair cortisol levels, psychological stress, anxiety, and depression in the three trimesters of pregnancy and postpartum. After childbirth, neonatal hair cortisol levels were also measured. We found that maternal hair cortisol levels in the first trimester negatively predicted neonatal hair cortisol levels. Perceived stress in the third trimester of pregnancy also predicted lower neonatal cortisol, whereas pregnancy-specific stress in the same trimester had a positive relation with neonatal cortisol. Cortisol is essential for embryonic and fetal development; consequently, if fetal synthesis of cortisol is affected by high maternal cortisol levels, such development could be impaired.

Maternal late-gestation metabolic stress is associated with changes in immune and metabolic responses of dairy calves

Metabolic stress in periparturient dairy cows is characterized by excessive lipid mobilization, inflammation, and oxidative stress that is associated with immune dysfunction. Thus, metabolic stress around the time calving is linked to the development of various early-lactation health disorders. Maternal status during late pregnancy can have carryover effects on several health and production variables of neonatal calves. However, the effects of metabolic stress during gestation on metabolic and immune responses of newborn calves remain unknown. Thus, we aimed to investigate whether metabolic stress in late-gestation dairy cows is associated with changes in the metabolic and immune responses of their offspring during the first month of life. Holstein-Friesian cows (n = 12) were blood sampled at 28 and 15 d before expected calving. The average between these 2 sampling points in the serum concentrations of nonesterified fatty acids (NEFA), haptoglobin (Hp), and oxidant status index (OSi)-defined as the ratio between reactive oxygen and nitrogen species and total antioxidant potential-were calculated as indicators of the degree of lipid mobilization, inflammation, and oxidant status (OS), respectively. Calves were subsequently divided into groups (n = 6 each) according to their dams' high or low degree of lipid mobilization, inflammation, and OS. The metabolic responses of calves in each of these groups were compared weekly throughout their first month of life by assessing serum concentration of NEFA, Hp, and OSi. Additionally, whole blood was obtained from calves at each sampling period and subjected to a lipopolysaccharide (LPS)-stimulated tumor necrosis factor-α (TNF-α) production assay to assess cell-mediated innate immunity against induced inflammatory responses, using high (5 μg/mL of blood) and low (10 ng/mL) concentrations of LPS. Calves born to cows with higher NEFA or OSi showed lower body weight at birth and throughout the study, whereas no association between any of the maternal groups and average daily gain at 4 wk of age was identified. Serum concentrations of reactive oxygen and nitrogen species were higher in calves exposed to higher maternal NEFA concentrations or OSi when compared with calves born to cows with lower values of these biomarkers. Calves exposed to high maternal OS also had higher circulating concentrations of Hp and TNF-α, indicating greater basal inflammatory responses when compared with calves born to cows with a lower OSi. In contrast, LPS-induced inflammatory responses were less robust in calves exposed to higher maternal biomarkers of inflammation or OS, suggesting compromised immune responses to microbial agonists. Collectively, these data suggest that prenatal exposure to maternal parameters of metabolic stress may adversely affect some metabolic and inflammatory responses of the offspring that could influence disease susceptibility.

The role of folic acid and selenium against oxidative damage from ethanol in early life programming: a review

There are disorders in children, covered by the umbrella term “fetal alcohol spectrum disorder” (FASD), that occur as result of alcohol consumption during pregnancy and lactation. They appear, at least in part, to be related to the oxidative stress generated by ethanol. Ethanol metabolism generates reactive oxygen species and depletes the antioxidant molecule glutathione (GSH), leading to oxidative stress and lipid and protein damage, which are related to growth retardation and neurotoxicity, thereby increasing the incidence of FASD. Furthermore, prenatal and postnatal exposure to ethanol in dams, as well as increasing oxidation in offspring, causes malnutrition of several micronutrients such as the antioxidant folic acid and selenium (Se), affecting their metabolism and bodily distribution. Although abstinence from alcohol is the only way to prevent FASD, it is possible to reduce its harmful effects with a maternal dietary antioxidant therapy. In this review, folic acid and Se have been chosen to be analyzed as antioxidant intervention systems related to FASD because, like ethanol, they act on the methionine metabolic cycle, being related to the endogenous antioxidants GSH and glutathione peroxidase. Moreover, several birth defects are related to poor folate and Se status.

Stress-related hormonal alterations, growth and pelleted starter intake in pre-weaning Holstein calves in response to thermal stress

This study aimed to investigate the effect of heat stress and month of birth on growth performance, pelleted starter intake, and stress-related hormones in Holstein calves. Birth weight and growth records, representing 4735 Holstein calves from a large commercial dairy herd in northern Mexico (25° N; 22.3 °C mean annual temperature) from 2013 to 2015, were analyzed. Temperature-humidity index (THI) at calving, season of birth, and month of birth were the independent variables, whereas growth traits were the dependent variables. Increased THI at birth from < 65 to > 85 units was associated with a decrease in birth weight from 39.3 to 38.7 kg. Calves subjected to high THI (> 75 units) at calving showed lesser (P < 0.01) pre-weaning gains (405 ± 97 g/calf/day), whereas those calves born with THI < 70 units presented the highest gains (466 ± 112 g/calf/day). Birth during the fall months reduced (P < 0.01) weaning weight by about 5 kg compared with winter months. Also, the pre-weaning average daily gain for calves born in the fall was about 70 g less (P < 0.01) than calves delivered in winter months. Plasma triiodothyronine and tetraiodothyronine levels were lower (1.02 ± 0.21 and 48 ± 7.9 ng/mL, respectively; P < 0.01) in summer and highest in winter (1.64 ± 0.48 and 66 ± 11 ng/mL, respectively). Mean plasma cortisol concentration was higher in heat-stressed calves born in summer (59 ± 40 ng/mL) than calves born in winter (20 ± 28 ng/mL). Pelleted starter intake 1 week before weaning was lowest (P < 0.01) in the fall (0.82 ± 0.26 kg/calf/day; mean ± SD) and highest in spring (1.26 ± 0.43 kg/calf/day). It was concluded that in this particular environment, heat stress affects birth weight and growth rate of Holstein calves. Thus, environmental management of the newborn calf during hot spring and summer months is warranted to optimize pelleted starter intake and calf growth rates.

Social determinants and BCG efficacy: a call for a socio-biological approach to TB prevention

A high burden of TB mortality persists despite the long-term availability of the bacillus Calmette-Guérin (BCG) vaccine, whose efficacy has been highly variable across populations. Innovative and alternative approaches to TB prevention are urgently needed while optimal biomedical tools continue to be developed. We call for new interdisciplinary collaborations to expand and integrate our understanding of how social determinants influence the biological processes that lead to TB disease, how this translates into differential BCG efficacy and, ultimately, how social protection interventions can play a role in reducing the global burden of TB. After providing an overview of the immune pathways important for the establishment of a response to the BCG vaccine, we outline how social determinants and psychosocial stressors can contribute to the observed variation in BCG efficacy above and beyond these biological factors. We conclude by proposing a new interdisciplinary research model based on the integration of social epidemiology theories with biomedical knowledge.

Prenatal maternal psychosocial stress and offspring's asthma and allergic disease: A systematic review and meta-analysis

BACKGROUND

Prenatal maternal stress may influence offspring's atopic risk through sustained cortisol secretion resulting from activation of the hypothalamic-pituitary axis (HPA), leading to Th2-biased cell differentiation in the foetus. We undertook a systematic review and meta-analysis investigating the relationship between prenatal maternal psychosocial stress and risk of asthma and allergy in the offspring.

METHODS

We searched 11 electronic databases from 1960 to 2016, searched the grey literature and contacted experts in the field. Type of stress indicator included mood disorders, anxiety, exposure to violence, bereavement and socio-economic problems occurring during pregnancy, both objectively and subjectively measured. We included all possible asthma and IgE-mediated allergy outcomes. We conducted random-effects meta-analyses to synthesize the data.

RESULTS

We identified 9779 papers of which 30 studies (enrolling >6 million participants) satisfied inclusion criteria. The quality of 25 studies was moderate, 4 were strong, and one was weak. Maternal exposure to any type of stressors was associated with an increased risk of offspring atopic eczema/dermatitis (OR 1.34, 95% CI 1.22-1.47), allergic rhinitis (OR 1.30, 95% CI 1.04-1.62), wheeze (OR 1.34, 95% CI 1.16-1.54) and asthma (OR 1.15, 95% CI 1.04-1.27). Exposure to anxiety and depression had strongest effect compared to other stressors. Exposure during the third trimester had the greatest impact compared to first and second trimesters. The increased risk was stronger for early-onset and persistent than for late-onset wheeze. Bereavement of a child (HR 1.28, 95% CI 1.10-1.48) or a spouse (HR 1.40, 95% CI 1.03-1.90) increased the risk of offspring asthma.

CONCLUSIONS

Exposure to prenatal maternal psychosocial stress was associated with increased risk, albeit modestly, of asthma and allergy in the offspring. The pronounced risk during the third trimester may represent cumulative stress exposure throughout pregnancy rather than trimester-specific effect. Our findings may represent a causal effect or a result of inherent biases in studies, particularly residual confounding.

Prenatal Maternal Stress and the Risk of Lifetime Wheeze in Young Offspring: An Examination by Stressor and Maternal Ethnicity

Prenatal psychosocial stressors may increase the risk of wheeze in young offspring, yet little attention has been given to the effects that maternal ethnicity may have on this relationship. From a population-based cohort of 1193 children, we assessed the effect of maternal prenatal stressors on the risk of lifetime wheeze in young offspring. We further studied whether maternal Latina ethnicity modified these associations. The risk of wheeze in the offspring was increased from high levels of pregnancy anxiety (aRR 1.40, 95 % CI 1.07, 1.83), negative life events (aRR 1.36, 95 % CI 1.06, 1.75), or low paternal support (aRR 1.41, 95 % CI 1.02, 1.96). The risk of lifetime wheeze was stronger in the offspring of Latina mothers than of White mothers for these same stressors. Multiple maternal prenatal stressors are associated with increased risk of lifetime wheeze in young offspring, with slight effect modification by Latina ethnicity.

Impact of prenatal stress on mother-infant dyadic behavior during the still-face paradigm

BACKGROUND

Mother-infant interaction provides important training for the infant's ability to cope with stress and the development of resilience. Prenatal stress (PS) and its impact on the offspring's development have long been a focus of stress research, with studies highlighting both harmful and beneficial effects. The aim of the current study was to examine the possible influence of both psychological stress and hypothalamic-pituitary-adrenal (HPA) axis activity during pregnancy with mother-child dyadic behavior following stress exposure.

METHODS

The behavior of 164 mother-infant dyads during the still-face situation was filmed at six months postpartum and coded into three dyadic patterns: 1) both positive, 2) infant protesting-mother positive, and 3) infant protesting-mother negative. PS exposure was assessed prenatally according to psychological measures (i.e., psychopathological, perceived and psychosocial PS; n = 164) and HPA axis activity measures (maternal salivary cortisol, i.e., cortisol decline and area under the curve with respect to ground (AUCg); n = 134).

RESULTS

Mother-infant dyads in both the high- and low-stress groups showed decreasing positive and increasing negative dyadic behavior in the reunion episode, which is associated with the well-known "still-face" and "carry-over" effect. Furthermore, mother-infant dyads with higher psychosocial PS exhibited significantly more positive dyadic behavior than the low psychosocial PS group in the first play episode, but not in the reunion episode. Similarly, mother-infant dyads with high HPA axis activity (i.e. high AUCg) but steeper diurnal cortisol decline (i.e. cortisol decline) displayed significantly less negative behavior in the reunion episode than dyads with low HPA axis activity. No significant results were found for psychopathological stress and perceived stress.

CONCLUSIONS

The results suggest a beneficial effect of higher psychosocial PS and higher prenatal maternal HPA axis activity in late gestation, which is in line with "stress inoculation" theories.

Developmental corticosterone treatment does not program immune responses in zebra finches (Taeniopygia guttata)

Developmental conditions may impact the expression of immune traits throughout an individual's life. Early-life challenges may lead to immunological constraints that are mediated by endocrine-immune interactions. In particular, individual differences in the ability to mount immune responses may be programmed by exposure to stressors or glucocorticoid hormones during development. To test this hypothesis, we experimentally elevated levels of the glucocorticoid hormone corticosterone during the nestling and fledgling periods in captive zebra finches (Taeniopygia guttata). We subsequently challenged birds with the antigen lipopolysaccharide (LPS) on days 60 and 100 post-hatch to determine if developmental exposure to elevated corticosterone impacted the later response to LPS. As measures of immune function, we quantified bacteria killing ability, haptoglobin concentrations, and LPS-specific antibody responses at multiple time points. We also measured circulating corticosterone concentrations during the experimental period and on day 60 before and after endotoxin challenge. During the experimental period, corticosterone treatment elevated corticosterone levels. Corticosterone treatment did not induce programming effects on immune function or corticosterone production. Independent of treatment, individuals with higher corticosterone concentrations during the nestling period had lower bacteria killing ability on day 36 and higher baseline corticosterone concentrations on day 60 post-hatch. These results suggest a limited role for corticosterone exposure during early life to mediate immunological constraints later in life. Manipulation of cortisol may be necessary to conclusively determine if developmental glucocorticoid exposure can program immune function in birds. To determine if developmental stress can program the immune response, exposure to environmentally relevant stressors should also be manipulated.

Acute maternal oxidant exposure causes susceptibility of the fetal brain to inflammation and oxidative stress

Background

Maternal exposure to environmental stressors poses a risk to fetal development. Oxidative stress (OS), microglia activation, and inflammation are three tightly linked mechanisms that emerge as a causal factor of neurodevelopmental anomalies associated with prenatal ethanol exposure. Antioxidants such as glutathione (GSH) and CuZnSOD are perturbed, and their manipulation provides evidence for neuroprotection. However, the cellular and molecular effects of GSH alteration in utero on fetal microglia activation and inflammation remain elusive.

Methods

Ethanol (EtOH) (2.5 g/kg) was administered to pregnant mice at gestational days 16–17. One hour prior to ethanol treatment, N-acetylcysteine (NAC) and L-buthionine sulfoximine (BSO) were administered to modulate glutathione (GSH) content in fetal and maternal brain. Twenty-four hours following ethanol exposure, GSH content and OS in brain tissues were analyzed. Cytokines and chemokines were selected based on their association with distinctive microglia phenotype M1-like (IL-1β, IFN γ, IL-6, CCL3, CCL4, CCL-7, CCL9,) or M2-like (TGF-β, IL-4, IL-10, CCL2, CCL22, CXCL10, Arg1, Chi1, CCR2 and CXCR2) and measured in the brain by qRT-PCR and ELISA. In addition, Western blot and confocal microscopy techniques in conjunction with EOC13.31 cells exposed to similar ethanol-induced oxidative stress and redox conditions were used to determine the underlying mechanism of microglia activation associated with the observed phenotypic changes.

Results

We show that a single episode of mild to moderate OS in the last trimester of gestation causes GSH depletion, increased protein and lipid peroxidation and inflammatory responses inclined towards a M1-like microglial phenotype (IL-1β, IFN-γ) in fetal brain tissue observed at 6–24 h post exposure. Maternal brain is resistant to many of these marked changes. Using EOC 13.31 cells, we show that GSH homeostasis in microglia is crucial to restore its anti-inflammatory state and modulate inflammation. Microglia under oxidative stress maintain a predominantly M1 activation state. Additionally, GSH depletion prevents the appearance of the M2-like phenotype, while enhancing morphological changes associated with a M1-like phenotype. This observation is also validated by an increased expression of inflammatory signatures (IL-1β, IFN-γ, IL-6, CCL9, CXCR2). In contrast, conserving intracellular GSH concentrations eliminates OS which precludes the nuclear translocation and more importantly the phosphorylation of the NFkB p105 subunit. These cells show significantly more pronounced elongations, ramifications, and the enhanced expression of M2-like microglial phenotype markers (IL-10, IL-4, TGF-β, CXCL10, CCL22, Chi, Arg, and CCR2).

Conclusions

Taken together, our data show that maintaining GSH homeostasis is not only important for quenching OS in the developing fetal brain, but equally critical to enhance M2 like microglia phenotype, thus suppressing inflammatory responses elicited by environmental stressors.

Electronic supplementary material

The online version of this article (10.1186/s12974-017-0965-8) contains supplementary material, which is available to authorized users.

Maternal late pregnancy anxiety and stress is associated with children's health: a longitudinal study

AIM

Maternal prenatal anxiety and stress (PNS) have been positively associated to physical health prob lems in offspring in the first year of life. Whether these associations are transient, persistent, or even progressive over time, is as yet unknown. The goal of this study is to investigate associations between late pregnancy PNS and child health from 18 months to age 6.

METHODS

Mothers were recruited in late pregnancy, and had uncomplicated, singleton pregnancies without physical health problems. Around week 37 of pregnancy, mothers reported on their PNS by means of questionnaires, and provided saliva for determination of circadian cortisol concentrations. Children's illnesses in the preceding year were assessed using maternal reports at 30, 48, 60, and 72 months. Antibiotic use was obtained from medical records between one and six years. Multilevel models (N¼174) showed a positive relation between maternal prenatal general and pregnancy-specific anxiety during late pregnancy and offspring respiratory illnesses and symptoms. Interaction effects with time indicated that more PNS was related to more respiratory illnesses until toddlerhood, but not later in life. Furthermore, maternal prenatal cortisol concentrations were related to child digestive illnesses. A steeper maternal cortisol decline over the day was related to more child digestive illnesses, until around three years of age. Finally, children of mothers who suffered more from daily hassles during pregnancy received more antibiotics between one and six years of age. PNS was not related to general and skin illnesses.

CONCLUSION

Summarizing, this study showed that late pregnancy anxiety and cortisol was associated with children's respiratory and digestive illnesses till the age of 3.0-3.5 years. Additionally, more daily hassles were related to more prescribed antibiotics between one and six years. These findings point in the direction of possible effects of PNS persisting beyond the first year of life and into toddlerhood, but disappearing at older ages.

Maternal programming of sex-specific responses to predator odor stress in adult rats

Prenatal stress mediated through the mother can lead to long-term adaptations in stress-related phenotypes in offspring. This study tested the long-lasting effect of prenatal exposure to predator odor, an ethologically relevant and psychogenic stressor, in the second half of pregnancy. As adults, the offspring of predator odor-exposed mothers showed increased anxiety-like behaviors in commonly used laboratory tasks assessing novelty-induced anxiety, increased defensive behavior in males and increased ACTH stress reactivity in females in response to predator odor. Female offspring from predator odor-exposed dams showed increased transcript abundance of glucocorticoid receptor (NR3C1) on the day of birth and FK506 binding protein 5 (FKBP5) in adulthood in the amygdala. The increase in FKBP5 expression was associated with decreased DNA methylation in Fkbp5 intron V. These results indicate a sex-specific response to maternal programming by prenatal predator odor exposure and a potential epigenetic mechanism linking these responses with modifications of the stress axis in females. These results are in accordance with the mismatch hypothesis stating that an animal's response to cues within its life history reflects environmental conditions anticipated during important developmental periods and should be adaptive when these conditions are concurring.

Climatic anomaly affects the immune competence of California sea lions

The past decades have been characterized by a growing number of climatic anomalies. As these anomalies tend to occur suddenly and unexpectedly, it is often difficult to procure empirical evidence of their effects on natural populations. We analysed how the recent sea surface temperature (SST) anomaly in the northeastern Pacific Ocean affects body condition, nutritional status, and immune competence of California sea lion pups. We found that pup body condition and blood glucose levels of the pups were lower during high SST events, although other biomarkers of malnutrition remained unchanged, suggesting that pups were experiencing early stages of starvation. Glucose-dependent immune responses were affected by the SST anomaly; specifically, pups born during high SST events had lower serum concentrations of IgG and IgA, and were unable to respond to an immune challenge. This means that not only were pups that were born during the SST anomaly less able to synthesize protective antibodies; they were also limited in their ability to respond rapidly to nonspecific immune challenges. Our study provides empirical evidence that atypical climatic conditions can limit energetic reserves and compromise physiological responses that are essential for the survival of a marine top predator.

Function and Dysfunction of Microglia during Brain Development: Consequences for Synapses and Neural Circuits

Many diverse factors, ranging from stress to infections, can perturb brain homeostasis and alter the physiological activity of microglia, the immune cells of the central nervous system. Microglia play critical roles in the process of synaptic maturation and brain wiring during development. Any perturbation affecting microglial physiological function during critical developmental periods could result in defective maturation of synaptic circuits. In this review, we critically appraise the recent literature on the alterations of microglial activity induced by environmental and genetic factors occurring at pre- and early post-natal stages. Furthermore, we discuss the long-lasting consequences of early-life microglial perturbation on synaptic function and on vulnerability to neurodevelopmental and psychiatric disorders.

Associations of Maternal Testosterone and Cortisol Levels With Health Outcomes of Mothers and Their Very-Low-Birthweight Infants

OBJECTIVE

Although the roles of testosterone and cortisol in various health problems have been extensively investigated, little is known about their associations with health outcomes in mothers and their very-low-birthweight (VLBW) infants when maternal testosterone and cortisol are examined together during the postpartum period.

METHOD

The 101 mother-VLBW infant pairs were recruited from the neonatal intensive care unit of a tertiary medical center in the southeastern United States. Demographic information, pregnancy and labor complications of mothers, and health and growth outcomes of infants were obtained from medical records and interviews with mothers. Maternal salivary testosterone and cortisol levels were determined using enzyme immunoassay.

RESULTS

Linear regression showed that mothers who were older and had a larger body mass index experienced more pregnancy complications, whereas mothers who were single and had a cesarean section experienced more labor complications. Generalized linear models showed that mothers with high cortisol levels had more antepartum hemorrhage, whereas infants of mothers with high cortisol levels had fewer neurological insults and shorter hospitalizations than other infants. More mothers experienced premature prolonged rupture of membranes (PPROM) than chorioamnionitis, and maternal medical complications were negatively associated with infant health outcomes except PPROM, which was positively associated with infant outcomes.

CONCLUSIONS

High maternal cortisol levels were associated with maternal health problems during pregnancy. Beneficial effects of PPROM and high maternal cortisol levels on infant health outcomes were important findings, and understanding the mechanisms of these relationships may be of practical value for clinicians and researchers.

Prenatal stress from trawl capture affects mothers and neonates: a case study using the southern fiddler ray (Trygonorrhina dumerilii)

Assessing fishing effects on chondrichthyan populations has predominantly focused on quantifying mortality rates. Consequently, sub-lethal effects of capture stress on the reproductive capacity of chondrichthyans are largely unknown. We investigated the reproductive consequences of capture on pregnant southern fiddler rays (Trygonorrhina dumerilii) collected from Swan Bay, Australia, in response to laboratory-simulated trawl capture (8 h) followed immediately by air exposure (30 min). Immediately prior to, and for up to 28 days post trawling, all females were measured for body mass (BM), sex steroid concentrations (17-β estradiol, progesterone, testosterone) and granulocyte to lymphocyte (G:L) ratio. At parturition, neonates were measured for total length (TL), BM and G:L ratio. Trawling reduced maternal BM and elevated the G:L ratio for up to 28 days. Trawling did not significantly affect any sex steroid concentrations relative to controls. Neonates from trawled mothers were significantly lower in BM and TL than control animals, and had an elevated G:L ratio. Our results show that capture of pregnant T. dumerilii can influence their reproductive potential and affect the fitness of neonates. We suggest other viviparous species are likely to be similarly affected. Sub-lethal effects of capture, particularly on reproduction, require further study to improve fisheries management and conservation of chondrichthyans.

Relationships among Maternal Stress and Depression, Type 2 Responses, and Recurrent Wheezing at Age 3 Years in Low-Income Urban Families

RATIONALE

Maternal depression and prenatal and early life stress may influence childhood wheezing illnesses, potentially through effects on immune development.

OBJECTIVES

To test the hypothesis that maternal stress and/or depression during pregnancy and early life are associated with recurrent wheezing and aeroallergen sensitivity and altered cytokine responses (enhanced type 2 or reduced virus-induced cytokine responses) from stimulated peripheral blood mononuclear cells at age 3 years.

METHODS

URECA (Urban Environment and Childhood Asthma) is a birth cohort at high risk for asthma (n = 560) in four inner cities. Maternal stress, depression, and childhood wheezing episodes were assessed by quarterly questionnaires beginning at birth. Logistic and linear regression techniques were used to examine the relation of maternal stress/depression to recurrent wheezing and peripheral blood mononuclear cell cytokine responses at age 3 years.

MEASUREMENTS AND MAIN RESULTS

Overall, 166 (36%) children had recurrent wheeze at age 3 years. Measures of maternal perceived stress at Years 2 and 3 were positively associated with recurrent wheeze (P < 0.05). Maternal depression (any year) was significantly associated with recurrent wheezing (P ≤ 0.01). These associations were also significant when considered in a longitudinal analysis of cumulative stress and depression (P ≤ 0.02). Neither stress nor depression was significantly related to aeroallergen sensitization or antiviral responses. Contrary to our original hypothesis, prenatal and Year 1 stress and depression had significant inverse associations with several type 2 cytokine responses.

CONCLUSIONS

In urban children at high risk for asthma, maternal perceived stress and depression were significantly associated with recurrent wheezing but not increased atopy or reduced antiviral responses.

Influence of the housing environment during sow gestation on maternal health, and offspring immunity and survival

In pig husbandry, pregnant females are often exposed to stressful conditions that may affect their physiology, behaviour or health and consequently the ability of their offspring to survive and develop. This study compared two different housing systems from insemination to 106 days of gestation, a conventional (C) and an enriched one (E), for maternal cortisol and immune parameters, as well as for the immune function and survival of their offspring. The C and E systems differed essentially for the housing design (slatted floor, 2.4 m2 per sow vs a deep straw litter and 3.4 m2 per sow). Results from Expt 1 (n = 108) demonstrated that C sows had higher salivary cortisol than E sows at gestational Day 102 (DG 102). Results from Expt 2 (n = 48) showed that, at DG 102, C sows had higher granulocyte counts and total plasma immunoglobulin G concentration than E sows, whereas lymphocyte number, haematocrit and haptoglobin plasma concentration were similar. Results from Expt 3 (n = 47) showed that plasma immunoglobulin G level at 5 and 27 days of age, hematocrit, white blood cell numbers and in vitro lymphocyte proliferation of piglets at 27 days of age were not influenced by maternal housing conditions. However, reproductive data collected in Expt 2 and 3 indicated that pre-weaning mortality was higher in C than E litters. In conclusion, the C system was associated with markers of increased stress and microbial aggression in gestating sows, and with greater piglet mortality during the suckling period without identified alterations in piglet immune function.

Prenatal Maternal Distress and Allergic Diseases in Offspring: Review of Evidence and Possible Pathways

Recent studies have suggested a close association between prenatal maternal distress and allergic diseases in the offspring. We selected relevant birth-cohort or national registry studies using a keyword search of the PubMed database and summarized current evidence on the impact of prenatal maternal distress on the development of offspring's allergic diseases. Moreover, we postulated possible pathways linking prenatal distress and allergic diseases based on relevant human and animal studies. Both dysregulated hypothalamic-pituitary-adrenal axis and increased oxidative stress may cause structural (altered brain/lung development) and functional (skewed immune development) changes, which may predispose the fetus to developing allergic diseases during childhood. Although many facts are yet to be discovered, changes in the placental response and epigenetic modification are presumed to mediate the whole process from maternal distress to allergic diseases. Maternal prenatal distress can also interact with other physical or environmental factors, including familial or physical factors, indoor and outdoor pollutants, and early childhood psychological distress. The gut-microbiome-brain axis and the role of the microbiome as an immune modulator should be considered when investigating the stress-allergy relationship and exploring potential intervention modalities. Further research is needed, and particular attention should be given to defining the most vulnerable subjects and critical time periods. To this end, studies exploring relevant biomarkers are warranted, which can enable us to explore adequate intervention strategies.

Prenatal Maternal Stress and the Risk of Asthma in Children

Emerging evidence indicate that maternal prenatal stress (MPS) can result in a range of long-term adverse effects in the offspring. The underlying mechanism of MPS is not fully understood. However, its complexity is emphasized by the number of purportedly involved pathways namely, placental deregulated metabolism of maternal steroids, impaired maturation of fetal HPA axis, imbalanced efflux of commensal bacteria across the placenta, and skewed immune development toward Th2. Fetal programming probably exerts a pivotal role in the end result of the above pathways through the modulation of gene expression. In this review, we highlight the current knowledge from epidemiological and experimental studies regarding the effects of MPS on asthma development in the offspring.

Evidence for an immune signature of prenatal alcohol exposure in female rats

Evidence for immune/neuroimmune disturbances as a possible root cause of a range of disorders, including neurodevelopmental disorders, is growing. Although prenatal alcohol exposure (PAE) impacts immune function, few studies to date have examined immune function in relation to long-term negative health outcomes following PAE, and most have focused on males. To fill this gap, we utilized a rat model to examine the effects of PAE on immune/neuroimmune function during early-life [postnatal day 1 (P1), P8, and P22] in PAE and control females. Due to the extensive interplay between the immune and endocrine systems, we also measured levels of corticosterone and corticosterone binding globulin (CBG). While corticosterone levels were not different among groups, CBG levels were lower in PAE offspring from P1 to P8, suggesting a lower corticosterone reservoir that may underlie susceptibility to inflammation. Spleen weights were increased in PAE rats on P22, a marker of altered immune function. Moreover, we detected a unique cytokine profile in PAE compared to control offspring on P8 - higher levels in the PFC and hippocampus, and lower levels in the hypothalamus and spleen. The finding of a specific immune signature in PAE offspring during a sensitive developmental period has important implications for understanding the basis of long-term immune alterations and health outcomes in children with Fetal Alcohol Spectrum Disorder (FASD). Our findings also highlight the future possibility that immune-based intervention strategies could be considered as an adjunctive novel therapeutic approach for individuals with FASD.

Prenatal maternal stress and wheeze in children: novel insights into epigenetic regulation

Psychological stress during pregnancy increases the risk of childhood wheeze and asthma. However, the transmitting mechanisms remain largely unknown. Since epigenetic alterations have emerged as a link between perturbations in the prenatal environment and an increased disease risk we used whole genome bisulfite sequencing (WGBS) to analyze changes in DNA methylation in mothers and their children related to prenatal psychosocial stress and assessed its role in the development of wheeze in the child. We evaluated genomic regions altered in their methylation level due to maternal stress based of WGBS data of 10 mother-child-pairs. These data were complemented by longitudinal targeted methylation and transcriptional analyses in children from our prospective mother-child cohort LINA for whom maternal stress and wheezing information was available (n = 443). High maternal stress was associated with an increased risk for persistent wheezing in the child until the age of 5. Both mothers and children showed genome-wide alterations in DNA-methylation specifically in enhancer elements. Deregulated neuroendocrine and neurotransmitter receptor interactions were observed in stressed mothers and their children. In children but not in mothers, calcium- and Wnt-signaling required for lung maturation in the prenatal period were epigenetically deregulated and could be linked with wheezing later in children’s life.

Behavioural traits propagate across generations via segregated iterative-somatic and gametic epigenetic mechanisms

Parental behavioural traits can be transmitted by non-genetic mechanisms to the offspring. Although trait transmission via sperm has been extensively researched, epidemiological studies indicate the exclusive/prominent maternal transmission of many non-genetic traits. Since maternal conditions impact the offspring during gametogenesis and through fetal/early-postnatal life, the resultant phenotype is likely the aggregate of consecutive germline and somatic effects; a concept that has not been previously studied. Here, we dissected a complex maternally transmitted phenotype, reminiscent of comorbid generalized anxiety/depression, to elementary behaviours/domains and their transmission mechanisms in mice. We show that four anxiety/stress-reactive traits are transmitted via independent iterative-somatic and gametic epigenetic mechanisms across multiple generations. Somatic/gametic transmission alters DNA methylation at enhancers within synaptic genes whose functions can be linked to the behavioural traits. Traits have generation-dependent penetrance and sex specificity resulting in pleiotropy. A transmission-pathway-based concept can refine current inheritance models of psychiatric diseases and facilitate the development of better animal models and new therapeutic approaches.

Physiological effects of psychological stress and infection in mothers can increase the incidence of anxiety and psychiatric diseases in offsprings and in subsequent generation. Here, Miklos Toth and colleagues show that intergenerational inheritance of neurological traits is propagated across multiple generations independently by parallel non-genetic mechanisms involving independent segregation of epigenetic specific loci.

Early life programming of pain: focus on neuroimmune to endocrine communication

Chronic pain constitutes a challenge for the scientific community and a significant economic and social cost for modern societies. Given the failure of current drugs to effectively treat chronic pain, which are based on suppressing aberrant neuronal excitability, we propose in this review an integrated approach that views pain not solely originating from neuronal activation but also the result of a complex interaction between the nervous, immune, and endocrine systems. Pain assessment must also extend beyond measures of behavioural responses to noxious stimuli to a more developmentally informed assessment given the significant plasticity of the nociceptive system during the neonatal period. Finally integrating the concept of perinatal programming into the pain management field is a necessary step to develop and target interventions to reduce the suffering associated with chronic pain. We present clinical and animal findings from our laboratory (and others) demonstrating the importance of the microbial and relational environment in programming pain responsiveness later in life via action on hypothalamo-pituitary adrenal (HPA) axis activity, peripheral and central immune system, spinal and supraspinal mechanisms, and the autonomic nervous system.

Prenatal and postnatal stress and wheeze in Mexican children: Sex-specific differences

BACKGROUND

Increasing evidence links early-life exposure to psychosocial stress with adverse childhood respiratory outcomes. The influence of exposure timing has not been completely elucidated.

OBJECTIVE

To examine the association between prenatal and postnatal maternal stress and wheeze in 417 children enrolled in a prospective birth cohort in Mexico City.

METHODS

Maternal negative life event (NLE) scores were ascertained in the second or third trimester of pregnancy and at the 48-month postnatal visit. Children's respiratory outcomes, caregiver report of ever wheeze, and wheeze in the past 12 months were obtained from the International Study of Asthma and Allergies in Childhood survey administered at 48 months. Associations between prenatal and postnatal NLE scores and wheeze were analyzed using a modified Poisson regression approach adjusting for covariates.

RESULTS

In separate models, higher maternal psychosocial stress during pregnancy (relative risk [RR], 1.12; 95% CI, 1.00-1.26) and postnatally (RR, 1.21; 95% CI, 1.08-1.35) were associated with increased risk of wheeze in the past 12 months with an evident exposure-response relationship. There was a significant interaction between postnatal stress and sex in relation to current wheeze. In a sex-stratified model, the association between postnatal stress and risk of wheeze in the past 12 months was stronger in girls (RR, 1.35; 95% CI, 1.13-1.61) than in boys (RR, 1.11; 95% CI, 0.97-1.27) (P for interaction = .04).

CONCLUSION

Prenatal and postnatal stress in mothers was associated with wheeze in preschool-aged children, and the effect of postnatal stress was stronger in girls. Understanding the temporal- and sex-specific effects of stress may better inform prevention strategies.

Effects of wildfire disaster exposure on male birth weight in an Australian population

Background and objectives: Maternal stress can depress birth weight and gestational age, with potential health effects. A growing number of studies examine the effect of maternal stress caused by environmental disasters on birth outcomes. These changes may indicate an adaptive response. In this study, we examine the effects of maternal exposure to wildfire on birth weight and gestational age, hypothesising that maternal stress will negatively influence these measures.

Methodology: Using data from the Australian Capital Territory, we employed Analysis of Variance to examine the influence of the 2003 Canberra wildfires on the weight of babies born to mothers resident in fire-affected regions, while considering the role of other factors.

Results: We found that male infants born in the most severely fire-affected area had significantly higher average birth weights than their less exposed peers and were also heavier than males born in the same areas in non-fire years. Higher average weights were attributable to an increase in the number of macrosomic infants. There was no significant effect on the weight of female infants or on gestational age for either sex.

Conclusions and implications: Our findings indicate heightened environmental responsivity in the male cohort. We find that elevated maternal stress acted to accelerate the growth of male fetuses, potentially through an elevation of maternal blood glucose levels. Like previous studies, our work finds effects of disaster exposure and suggests that fetal growth patterns respond to maternal signals. However, the direction of the change in birth weight is opposite to that of many earlier studies.

Marital Quality and Stress in Pregnancy Predict the Risk of Infectious Disease in the Offspring: The Norwegian Mother and Child Cohort Study

OBJECTIVES

The aim of this study was to explore the degree to which couples' relationship dissatisfaction and stressful life events during pregnancy predict the risk of infectious disease in the offspring during their first year of life.

METHODS

Data were obtained from the Norwegian Mother and Child Cohort Study, conducted by the Norwegian Institute of Public Health. Pregnant women completed questionnaires in week 30 of pregnancy concerning the couples' relationship satisfaction and stressful life events. In follow-up questionnaires, the women reported whether their children (n = 74,801) had been subject to various categories of infectious disease: the common cold, throat infection, bronchitis, RS virus, pneumonia, pseudocroup, gastric flu, ear infection, conjunctivitis and urinary tract infection. Reports from two age groups of infants were used. Associations between the predictor and outcome variables were assessed via logistic regression and linear regression analyses.

RESULTS

Separate logistic regression analyses for each disease and age group showed that prenatal relationship dissatisfaction and stressful life events were significantly associated with all reported categories of infectious disease. After controlling for socioeconomic factors, social support, smoking, breastfeeding, maternal depression, the sex of the offspring, and use of child care, 29 out of 32 tested associations were statistically significant. Finally, multivariate linear regression analyses showed that prenatal relationship dissatisfaction and stressful life events were significantly associated with the frequency, as well as the variety, of infectious disease in the offspring.

Transcriptomic and Epigenetic Profiling of the Lung of Influenza-Infected Pigs: A Comparison of Different Birth Weight and Susceptibility Groups

Influenza viruses are a common cause of respiratory disease in swine. Infections range in severity from asymptomatic to causing significant morbidity. The main objective of this study was to compare lung transcriptomic and epigenetic responses to influenza infection in pigs from high or low birth weight litters. The latter is a potential indicator of intrauterine growth restriction, a significant risk factor for prenatal programming effects. Individual pigs from high (HBW) or low birth weight (LBW) litters (n = 17) were inoculated with influenza A virus and euthanized 48 hours later. Lesion severity and viral loads were assessed as previously described. The transcriptional response to infection in LBW and HBW groups (n = 16) was assessed by microarray. A separate analysis of pigs classified as 'Resilient' (RES) or 'Susceptible' (SUS) (n = 6) on the basis of severity of lung pathology was also conducted. Eight genes were confirmed as differentially expressed for the birth weight comparison, including three antiviral genes with lower expression in LBW: ISG15, OAS1, and OAS2 (P<0.05). The promoter region methylation status of these three genes was assessed for each birth weight group, and no differences were found. These expression data are consistent with our previous finding that LBW pigs had less severe lesion scores and a trend towards lower viral titres in lung than the HBW cohort. The SUS v RES comparison identified 91 differentially expressed genes (FDR<0.05) that were enriched with functional annotation terms and pathways associated with inflammation. The cytokine genes IL6, IL8, and CCL2 were all upregulated in SUS pigs, and may have driven disease severity in these animals. In conclusion, this study found no evidence that the transcriptional immune response to influenza was adversely affected by low litter birth weight, but did identify several candidate genes for driving disease pathology.

The synergistic effect of density stress during the maternal period and adulthood on immune traits of root vole (Microtus oeconomus) individuals-a field experiment

The literature reveals that stress in early life or adulthood can influence immune function. As most studies on this are from the laboratory, there is a need for replicated studies in wild animals. This study aims to examine the effects of density stress during the maternal period and adulthood on immune traits of root vole (Microtus oeconomus) individuals. Four replicated high- and low-density parental populations were established, from which we obtained offspring and assigned each into four enclosures, two for each of the two density treatments used in establishing parental populations. The F1 offspring fecal corticosterone metabolite response to acute immobilization stress, anti-keyhole limpet hemocyanin immunoglobulin G (anti-KLH IgG) level, phytohemagglutinin (PHA)-delayed hypersensitivity and hematology at the end of the first breeding season, and prevalence and intensity of coccidial infection throughout the two breeding seasons, were tested. Density-induced maternally stressed offspring had delayed responses to acute immobilization stress. Density-stressed offspring as adults had reduced anti-KLH IgG levels and PHA responses, and the effects further deteriorated in maternally stressed offspring, leading to higher coccidial infection in the first breeding season than in the second. No correlations were found between immune traits or coccidial infection and survival over winter. These findings indicated that the combined density stresses during the maternal period and adulthood exhibited negative synergistic effects on immune traits. The synergistic effects lead to higher coccidial infection; however, this consequently reduced the risk of subsequent infection. The increased coccidial infection mediated by the synergistic effects may have an adaptive value in the context of the environment.

Acute brief heat stress in late gestation alters neonatal calf innate immune functions

Heat stress, as one of the environmental stressors affecting the dairy industry, compromises the cow milk production, immune function, and reproductive system. However, few studies have looked at how prenatal heat stress (HS) affects the offspring. The objective of this study was to evaluate the effect of HS during late gestation on calf immunity. Calves were born to cows exposed to evaporative cooling (CT) or HS (cyclic 23-35°C) for 1 wk at 3 wk before calving. Both bull and heifer calves (CT, n=10; HS, n=10) were housed in similar environmental temperatures after birth. Both CT and HS calves received 3.78 L of pooled colostrum within 12 h after birth and were fed the same diet throughout the study. In addition to tumor necrosis factor α, IL-1β, IL-1 receptor antagonist (IL-1RA), and toll-like receptor (TLR)2, and TLR4 mRNA expression, the expression of CD14(+) and CD18(+) cells, and DEC205(+) dendritic cells were determined in whole blood samples at d 0, 3, 7, 14, 21, and 28. The neutrophil to lymphocyte ratio, differential cell counts, and the hematocrit were also determined. During late gestation, the HS cows had greater respiration rates, rectal temperatures, and tended to spend more time standing compared with the CT cows. The HS calves had less expression of tumor necrosis factor-α and TLR2 and greater levels of IL-1β, IL-1RA, and TLR4 compared with CT calves. The HS calves also had a greater percentage of CD18(+) cells compared with the CT calves. Additionally, a greater percentage of neutrophils and lesser percentage of lymphocytes were in the HS calves compared with the CT calves. The results indicate that biomarkers of calves' immunity are affected in the first several weeks after birth by HS in the dam during late gestation.

Long-Term Changes in Proliferative Capacity of Thymocytes and Splenocytes in Mouse Progeny after Stimulation of Maternal Lymphocyte Proliferation at Early Terms of Pregnancy

We studied the possibility of prenatal programming of proliferative potential of thymocytes and splenocytes in the offspring of C57Bl/6 mice via concanavalin A mitogen stimulation of lymphocyte proliferation in maternal organism at the early terms of pregnancy before the formation of immune system organs in the embryo. The offspring demonstrated elevated proliferative activity of thymocytes and splenocytes, enhanced lymphocyte proliferation, and increased production of IL-2 in in vitro response to concanavalin A during the prepubertal period and puberty. Mitogen stimulation of the maternal immune system in early pregnancy results in long-term enhancement of the proliferative potential of thymus and splenic cells in the offspring.

Abnormal immune system development and function in schizophrenia helps reconcile diverse findings and suggests new treatment and prevention strategies

Extensive research implicates disturbed immune function and development in the etiology and pathology of schizophrenia. In addition to reviewing evidence for immunological factors in schizophrenia, this paper discusses how an emerging model of atypical immune function and development helps explain a wide variety of well-established - but puzzling - findings about schizophrenia. A number of theorists have presented hypotheses that early immune system programming, disrupted by pre- and perinatal adversity, often combines with abnormal brain development to produce schizophrenia. The present paper focuses on the hypothesis that disruption of early immune system development produces a latent immune vulnerability that manifests more fully after puberty, when changes in immune function and the thymus leave individuals more susceptible to infections and immune dysfunctions that contribute to schizophrenia. Complementing neurodevelopmental models, this hypothesis integrates findings on many contributing factors to schizophrenia, including prenatal adversity, genes, climate, migration, infections, and stress, among others. It helps explain, for example, why (a) schizophrenia onset is typically delayed until years after prenatal adversity, (b) individual risk factors alone often do not lead to schizophrenia, and (c) schizophrenia prevalence rates actually tend to be higher in economically advantaged countries. Here we discuss how the hypothesis explains 10 key findings, and suggests new, potentially highly cost-effective, strategies for treatment and prevention of schizophrenia. Moreover, while most human research linking immune factors to schizophrenia has been correlational, these strategies provide ethical ways to experimentally test in humans theories about immune function and schizophrenia. This article is part of a Special Issue entitled SI: Neuroimmunology in Health And Disease.

Early adversity, immunity and infectious disease

Complex interactions between biological, behavioral and environmental factors are involved in mediating individual differences in health and disease. In this review, we present evidence suggesting that increased vulnerability to infectious disease may be at least, in part, due to long-lasting effects of early life psychosocial adversities. Studies have shown that maternal psychosocial stress during pregnancy is associated with long lasting changes in immune function and disease resistance in the offspring. Studies further indicated that harsh environmental conditions during the neonatal period may also cause lasting changes in host response to infectious disease. Although the mechanisms involved in these effects have not been fully examined, several potential mediators have been described, including changes in the development of the offspring hypothalamic-pituitary-adrenal axis, alterations in epigenetic pathways, stress-related maternal health risk behavior and infection during pregnancy. Although there are ample literature indicating that perinatal psychosocial stress increases vulnerability to disease, other reports suggest that mild predictable stressors may benefit the organism and allow better coping with future stressors. Thus, understanding the possible consequences of perinatal adversities and the mechanisms that are involved in immune regulation is important for increasing awareness to the potential outcomes of early negative life events and providing insight into potential therapies to combat infection in vulnerable individuals.

Effect of maternal anxiety on maternal serum and fetal cord blood cortisol

INTRODUCTION

Prenatal exposure to maternal anxiety and inappropriate levels of glucocorticoids may influence intrauterine growth and affect later health outcomes. We examined the relationship between maternal anxiety, maternal serum, and fetal cord blood cortisol.

METHODS

Eighty-four pregnant women with gestational age above 37 weeks admitted for elective caesarian section were studied. The Spielberger State-Trait Anxiety Inventory was used to assess maternal anxiety. Maternal blood was sampled immediately before caesarean section. Cord blood sample was taken immediately after birth. Multiple regression analysis was performed.

RESULTS

Maternal trait anxiety score, maternal serum cortisol, and neonatal weight were associated with the fetal cord blood cortisol (r = 0.21, P = 0.04). Bivariate correlation analysis revealed a positive correlation between maternal trait anxiety and fetal cord blood cortisol (r = 0.21, P = 0.03).

CONCLUSIONS

These data suggested that high maternal trait anxiety increases fetus cord blood cortisol and may regulate fetal growth.

Prenatal arsenic exposure alters the programming of the glucocorticoid signaling system during embryonic development

The glucocorticoid system, which plays a critical role in a host of cellular functions including mood disorders and learning and memory, has been reported to be disrupted by arsenic. In previous work we have developed and characterized a prenatal moderate arsenic exposure (50ppb) model and identified several deficits in learning and memory and mood disorders, as well as alterations within the glucocorticoid receptor signaling system in the adolescent mouse. In these present studies we assessed the effects of arsenic on the glucocorticoid receptor (GR) pathway in both the placenta and the fetal brain in response at two critical periods, embryonic days 14 and 18. The focus of these studies was on the 11β-hydroxysteroid dehydrogenase enzymes (11β-HSD1 and 11β-HSD2) which play a key role in glucorticoid synthesis, as well as the expression and set point of the GR negative feedback regulation. Negative feedback regulation is established early in development. At E14 we found arsenic exposure significantly decreased expression of both protein and message in brain of GR and the 11β-HSD1, while 11β-HSD2 enzyme protein levels were increased but mRNA levels were decreased in the brain. These changes in brain protein continued into the E18 time point, but mRNA levels were no longer significantly altered. Placental HSD11B2 mRNA was not altered by arsenic treatment but protein levels were elevated at E14. GR placental protein levels were decreased at E18 in the arsenic exposed condition. This suggests that arsenic exposure may alter GR expression levels as a consequence of a prolonged developmental imbalance between 11β-HSD1 and 11β-HSD2 protein expression despite decreased 11HSDB2 mRNA. The suppression of GR and the failure to turn down 11β-HSD2 protein expression during fetal development may lead to an altered set point for GR signaling throughout adulthood. To our knowledge, these studies are the first to demonstrate that gestational exposure to moderate levels of arsenic results in altered fetal programming of the glucocorticoid system.

Mechanisms underlying the effects of prenatal psychosocial stress on child outcomes: beyond the HPA axis

Accumulating evidence from preclinical and clinical studies indicates that maternal psychosocial stress and anxiety during pregnancy adversely affect child outcomes. However, knowledge on the possible mechanisms underlying these relations is limited. In the present paper, we review the most often proposed mechanism, namely that involving the HPA axis and cortisol, as well as other less well-studied but possibly relevant and complementary mechanisms. We present evidence for a role of the following mechanisms: compromised placental functioning, including the 11β-HSD2 enzyme, increased catecholamines, compromised maternal immune system and intestinal microbiota, and altered health behaviors including eating, sleep, and exercise. The roles of (epi)genetics, the postnatal environment and the fetus are also discussed. We conclude that maternal prenatal psychosocial stress is a complex phenomenon that affects maternal emotions, behavior and physiology in many ways, and may influence the physiology and functioning of the fetus through a network of different pathways. The review concludes with recommendations for future research that helps our understanding of the mechanisms by which maternal prenatal stress exerts its effect on the fetus.

The effect of perinatal anxiety on bronchiolitis is influenced by polymorphisms in ROS-related genes

Background

Exposure to perinatal anxiety affects disease susceptibility in offspring but studies on the association between perinatal anxiety and gene polymorphisms are lacking. This study aimed to elucidate the interaction between perinatal anxiety and polymorphisms in antioxidant defense and innate immunity genes on the development of respiratory tract infections (RTIs) during early infancy.

Methods

Trait anxiety levels in 440 women were assessed by the State-Trait Anxiety Inventory during late gestation. The occurrence of RTIs, including bronchiolitis, during the first year of life was assessed by parent-reported doctor diagnosis. Polymorphisms in glutathione S-transferase P-1 (GSTP1, rs1695) and CD14 (rs2569190) were genotyped using the TaqMan assay. Copy number variations of GSTT1 were measured by real-time polymerase chain reaction.

Results

Exposure to high levels of perinatal anxiety increased the risk of bronchiolitis in the first year of life (adjusted odds ratio [aOR], 1.30; 95% confidence interval [CI]: 1.00–1.80), in particular among children with the AG + GG genotype of GSTP1 or the GSTT1 null genotype (aOR 3.36 and 2.79). In infants with the TC + CC genotype of CD14, high levels of perinatal anxiety were associated with an increased risk of upper RTI, lower RTI, and bronchiolitis (aOR 2.51, 4.60, and 4.31, respectively).

Conclusions

Perinatal maternal anxiety levels affect the occurrence of bronchiolitis in offspring. The effect of perinatal anxiety on the occurrence of bronchiolitis during infancy was influenced by genetic polymorphisms in antioxidant defense and innate immunity genes.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2466-14-154) contains supplementary material, which is available to authorized users.

Pre-birth world and the development of the immune system: mum's diet affects our adult health: new insight on how the diet during pregnancy permanently influences offspring health and immune fitness

Secondary lymphoid organs form in utero through an inherited and well-established developmental program. However, maternal non-heritable features can have a major impact on the gene expression of the embryo, hence influencing the future health of the offspring. Recently, maternal retinoids were shown to regulate the formation of immune structures, shedding light on the role of maternal nutrition in the genetic signature of emergent immune cells. Here we highlight evidence showing how the maternal diet influences the establishment of the immune system, and we also discuss how unbalanced maternal diets may set the response to infection and vaccination in the progeny.