Fetal programming for adult disease: where next?

Keap1-Nrf2 regulated redox signaling in utero: Priming of disease susceptibility in offspring

Intrauterine exposure to gestational diabetes, pre-eclampsia or intrauterine growth restriction alters the redox status of the developing fetus. Such pregnancy-related diseases in most cases do not have a readily identifiable genetic cause, and epigenetic 'priming' mechanisms in utero may predispose both mother and child to later-life onset of cardiovascular and metabolic diseases. The concept of 'fetal programing' or 'developmental priming' and its association with an increased risk of disease in childhood or adulthood has been reviewed extensively. This review focuses on adaptive changes in the in utero redox environment during normal pregnancy and the consequences of alterations in redox control associated with pregnancies characterized by oxidative stress. We evaluate the evidence that the Keap1-Nrf2 pathway is important for protecting the fetus against adverse conditions in utero and may itself be subject to epigenetic priming, potentially contributing to an increased risk of vascular disease and insulin resistance in later life.

Impact of maternal obesity on perinatal and childhood outcomes

Maternal obesity is of major consequence, affecting every aspect of maternity care including both short- and long-term effects on the health of the offspring. Obese mothers are at a higher risk of developing gestational diabetes and pre-eclampsia, potentially exposing the foetus to an adverse intrauterine environment. Maternal obesity is linked to foetal macrosomia, resulting in increased neonatal and maternal morbidity. Foetal macrosomia is a result of a change in body composition in the neonate with an increase in both percentage fat and fat mass. Maternal obesity and gestational weight gain are associated with childhood obesity, and this effect extends into adulthood. Childhood obesity in turn increases chances of later life obesity, thus type 2 diabetes, and cardiovascular disease in the offspring. Further clinical trials of lifestyle and, potentially, pharmacological interventions in obese pregnant women are required to determine whether short- and long-term adverse effects for the mother and child can be reduced.

Preterm birth and random plasma insulin levels at birth and in early childhood

IMPORTANCE

Although previous reports have linked preterm birth with insulin resistance in children and adults, it is not known whether altered insulin homeostasis is detectable at birth and tracks from birth through childhood.

OBJECTIVE

To investigate whether preterm birth is associated with elevated plasma insulin levels at birth and whether this association persists into early childhood.

DESIGN, SETTING, AND PARTICIPANTS

A prospective birth cohort of 1358 children recruited at birth from 1998 to 2010 and followed-up with prospectively from 2005 to 2012 at the Boston Medical Center in Massachusetts.

MAIN OUTCOMES AND MEASURES

Random plasma insulin levels were measured at 2 time points: at birth (cord blood) and in early childhood (venous blood). The median age was 1.4 years (interquartile range [IQR], 0.8-3.3) among 4 gestational age groups: full term (≥39 wk), early term (37-38 wk), late preterm (34-36 wk), and early preterm (<34 wk).

RESULTS

The geometric mean of insulin levels at birth were 9.2 µIU/mL (95% CI, 8.4-10.0) for full term; 10.3 µIU/mL (95% CI, 9.3-11.5) for early term; 13.2 µIU/mL (95% CI, 11.8-14.8) for late preterm; and 18.9 µIU/mL (95% CI, 16.6-21.4) for early preterm. In early childhood, these levels were 11.2 µIU/mL (95% CI, 10.3-12.0) for full term; 12.4 µIU/mL (95% CI, 11.3-13.6) for early term; 13.3 µIU/mL (95% CI, 11.9-14.8) for late preterm; and 14.6 µIU/mL (95% CI, 12.6-16.9) for early preterm. Insulin levels at birth were higher by 1.13-fold (95% CI, 0.97-1.28) for early term, 1.45-fold (95% CI, 1.25-1.65) for late preterm, and 2.05-fold (95% CI, 1.69-2.42) for early preterm than for those born full term. In early childhood, random plasma insulin levels were 1.12-fold (95% CI, 0.99-1.25) higher for early term, 1.19-fold (95% CI, 1.02-1.35) for late preterm, and 1.31-fold (95% CI, 1.10-1.52) for early preterm than those born full term. The association was attenuated after adjustment for postnatal weight gain and was not significant after adjustment for insulin levels at birth. Infants ranked in the top insulin tertile at birth were more likely to remain in the top tertile (41.2%) compared with children ranked in the lowest tertile (28.6%) in early childhood.

CONCLUSIONS AND RELEVANCE

There was an inverse association between gestational age and elevated plasma insulin levels at birth and in early childhood. The implications for future development of insulin resistance and type 2 diabetes warrant further investigation.

Maternal nutrition and offspring's adulthood NCD's: a review

Overnutrition and undernutrition during pregnancy are closely related to pregnancy outcome as well as neonatal and perinatal outcomes. This and more, from various published data it seems that the effect of maternal nutrition during fetal life stretches far beyond the neonatal period, and influences health issues in adulthood, from cardiovascular and metabolic disorders through mental illnesses. The purpose of this review is to update about overnutrition and undernutrition during pregnancy and their effect on noncommunicable adulthood diseases, and about leading theories on the subject.

Is the birthweight of singletons born after IVF reduced by ovarian stimulation or by IVF laboratory procedures?

Singletons born after IVF are at risk of adverse pregnancy outcome, the cause of which is unknown. The present study investigated the influence of ovarian stimulation and IVF laboratory procedure on birthweight. Birthweight of singleton pregnancies resulting from IVF treatment with (n=161) and without ovarian stimulation (using a modified natural cycle (MNC) protocol; n=158), and spontaneous conceptions in subfertile patients (n=132) were compared. Mean+/-SD birthweight of singletons after conventional IVF with ovarian stimulation, MNC-IVF and natural conception were 3271+/-655, 3472+/-548 and 3527+/-582 g (P=0.001). After adjustment for biological and social confounders, the difference in birthweight between conventional IVF and MNC-IVF was reduced to 88 g and the differences between conventional IVF and MNC-IVF versus spontaneous conceptions to 123 and 23 g, respectively. The results lead to three conclusions. First, a major part of the crude differences in birthweight between the three groups is related to patient and pregnancy characteristics. Second, the IVF laboratory procedure has no influence on birthweight. Third, although a trend towards lower birthweight after ovarian stimulation was found, an adverse effect of ovarian stimulation on birthweight was not substantiated.

The Relationship of Low Birth Weight to Blood Pressure, Cortisol Levels, and Reactivity in African American Adolescents: A Pilot Study

Epidemiological studies show a relationship between low birth weight (LBW) and adult cardiovascular disease. Blood pressure and cortisol hyper-responsiveness during physiologic stress may function as biological markers for hypertension. The purpose of this study was to explore the relationship of blood pressure and cortisol levels with induced physiologic stress to LBW. Forty-eight adolescents, 14 to 16 years old, were tested for blood pressure and cortisol levels at rest and in response to a physiological stressor. A history of LBW was obtained. Multivariate repeated measures analysis and chi-square analyses were used to determine the changes in blood pressure and cortisol.Forty-eight African American adolescents, mean age 14.98 years (SD = 0.33), completed the study. Thirteen adolescents (27%) reported LBW. Although not statistically significant, systolic and diastolic pressures were 6 mmHg and 2 mmHg, respectively, higher in the LBW group when compared with the normal birth weight (NBW) group (p = 0.33 and p = 0.21, and 6 (46%) had elevated blood pressures (p = 0.005)). Blood pressure changes, cardiovascular reactivity, elevated blood, or all of these were significantly higher in LBW African American adolescents (p = 0.006). Cardiovascular reactivity was not significant (p = 0.208)). The mean average cortisol levels were (18.8 nmol/dL (SD = 11.0) but comparable (p = 0.72)). The number of LBW adolescents with cortisol reactivity was significantly higher that in the NBW group (p = 0.041). This study adds support to the association of LBW to biological markers of hypertension in childhood.

Developmental exposure to terbutaline and chlorpyrifos, separately or sequentially, elicits presynaptic serotonergic hyperactivity in juvenile and adolescent rats

Developmental exposure to unrelated neurotoxicants can nevertheless converge on common final targets so as to exacerbate damage or functional deficits. We examined the effects of developmental exposure to terbutaline, a beta2-adrenergic receptor agonist used to arrest preterm labor, and chlorpyrifos, a widely used organophosphate pesticide, on serotonin (5HT) systems. Treatments were chosen to parallel periods typical of human developmental exposures, terbutaline (10 mg/kg) on postnatal days (PN) 2-5 and chlorpyrifos (5 mg/kg) on PN11-14, with assessments conducted in juvenile and adolescent stages (PN21, PN30 and PN45), comparing each agent alone as well as sequential administration of both. By itself, terbutaline produced persistent 5HT presynaptic hyperactivity as evidenced by increased 5HT turnover in brain regions containing 5HT terminal zones; this effect was similar to that seen in earlier studies with chlorpyrifos administration during the same early postnatal period. Later administration of chlorpyrifos (PN11-14) produced a transient increase in 5HT turnover during the juvenile stage, and the sequential exposure paradigm, terbutaline followed by chlorpyrifos, showed a corresponding increase in effect over either agent alone. In combination with our earlier work on 5HT receptors, these results indicate that terbutaline is a developmental neurotoxicant that targets the 5HT system, findings that lend a mechanistic underpinning to clinical indications of elevated childhood psychiatric disorders in the offspring of women treated with beta-agonist tocolytics. Equally importantly, the interaction between terbutaline and chlorpyrifos suggests that tocolytic therapy may alter the subsequent susceptibility to common environmental toxicants.

Dysregulation of the circulating and tissue-based renin-angiotensin system in preeclampsia

The renin-angiotensin system (RAS) participates in preeclampsia; however, the relative contributions from the circulating RAS and the tissue-based, uteroplacental RAS are unknown. We hypothesized that the tissue-based uteroplacental RAS is dysregulated in preeclampsia. We performed microarray and gene expression studies and confirmed the findings on the protein level by immunohistochemistry in ureteroplacental units from 10 preeclamptic women and 10 women with uneventful pregnancies. All of the women were delivered by cesarean section. We also analyzed plasma renin activity and circulating agonistic angiotensin II type 1 (AT1) receptor autoantibodies. In preeclampsia, we found that the angiotensin II AT1 receptor gene was 5-fold upregulated in decidua (maternal origin). We also found AT1 autoantibodies in preeclamptic women and in their offspring by neonatal cardiomyocyte bioassay compared with women with normal pregnancies and their infants (mother: 17.5+/-2.2 versus 0.05+/-0.4; fetus: 14.5+/-1.8 versus 0.5+/-0.5 Deltabpm). Gene expressions for renin (35.0-fold), angiotensin-converting enzyme (2.9-fold), and angiotensinogen (8.9-fold) were higher in decidua than placenta (fetal origin) in both control and preeclamptic women, whereas the AT1 receptor was expressed 10-fold higher in placenta than in decidua in both groups. Our findings elucidate the ureteroplacental unit RAS in preeclamptic and normal pregnancies. We found that, in preeclampsia, the AT1 receptor expression is particularly high in decidua, combined with pregnancy-specific tissue RAS involving decidual angiotensin II production and AT1 autoantibodies. We also showed that AT1 autoantibodies cross the ureteroplacental barrier. These components could participate in the pathophysiology of preeclampsia.

The short- and long-term implications of maternal obesity on the mother and her offspring

Obesity's increasing prevalence has reached epidemic proportions in the USA, with close to one-third of the adult population affected in 2000. Additionally, there is increasing prevalence of obesity in other industrialised areas of the world such as Europe. Of potentially more concern is the potential risks associated with obesity and related metabolic complications in the developing world. The maternal, fetal, peripartum and neonatal complications of obesity in pregnancy have far-reaching implications for both mother and offspring. Of alarming interest is the increasing rate of obesity among adolescents and the cycle of obesity in future generations it portends. The purpose in this review is to briefly review the maternal perinatal morbidities associated with maternal pregravid obesity. Additionally, we will review evidence of both short- and long-term effect of maternal obesity on the in utero environment as it relates to fetal growth, neonatal body composition and adolescent obesity.

Early-life risk factors for Alzheimer disease

Research findings obtained over the past 20 years suggest that Alzheimer disease (AD) may have its origins in early life. In this review, we consider the evidence for early-life risk factors for this illness. We propose that risk factors that predict neuropathology are largely distinct from those related to the clinical expression of Alzheimer disease. Early-life risk factors for pathology include genes, chromosomal abnormalities, head injury, insulin resistance, and inflammation. With regard to risk factors for clinical expression of Alzheimer disease, six general groups of childhood exposures are reviewed: (1) perinatal conditions, (2) early-life brain development, (3) early-life body growth, (4) early-life socioeconomic conditions, (5) environmental enrichment, and (6) cognitive reserve. The literature reviewed suggests that risk of Alzheimer disease is probably not determined in any single time period but results from the complex interplay between genetic and environmental exposures throughout the life course. Enhancement or preservation of brain or cognitive reserve could delay the onset of Alzheimer disease and in some cases prevent the disease from occurring altogether.

Workgroup report: Implementing a national occupational reproductive research agenda--decade one and beyond

The initial goal of occupational reproductive health research is to effectively study the many toxicants, physical agents, and biomechanical and psychosocial stressors that may constitute reproductive hazards in the workplace. Although the main objective of occupational reproductive researchers and clinicians is to prevent recognized adverse reproductive outcomes, research has expanded to include a broader spectrum of chronic health outcomes potentially affected by reproductive toxicants. To aid in achieving these goals, the National Institute for Occupational Safety and Health, along with its university, federal, industry, and labor colleagues, formed the National Occupational Research Agenda (NORA) in 1996. NORA resulted in 21 research teams, including the Reproductive Health Research Team (RHRT). In this report, we describe progress made in the last decade by the RHRT and by others in this field, including prioritizing reproductive toxicants for further study; facilitating collaboration among epidemiologists, biologists, and toxicologists; promoting quality exposure assessment in field studies and surveillance; and encouraging the design and conduct of priority occupational reproductive studies. We also describe new tools for screening reproductive toxicants and for analyzing mode of action. We recommend considering outcomes such as menopause and latent adverse effects for further study, as well as including exposures such as shift work and nanomaterials. We describe a broad domain of scholarship activities where a cohesive system of organized and aligned work activities integrates 10 years of team efforts and provides guidance for future research.

Disruption of rat forebrain development by glucocorticoids: critical perinatal periods for effects on neural cell acquisition and on cell signaling cascades mediating noradrenergic and cholinergic neurotransmitter/neurotrophic responses

Glucocorticoids are the consensus treatment for the prevention of respiratory distress in preterm infants, but there is evidence for increased incidence of neurodevelopmental disorders as a result of their administration. We administered dexamethasone (Dex) to developing rats at doses below or within the range of those used clinically, evaluating the effects on forebrain development with exposure in three different stages: gestational days 17-19, postnatal days 1-3, or postnatal days 7-9. At 24 h after the last dose, we evaluated biomarkers of neural cell acquisition and growth, synaptic development, neurotransmitter receptor expression, and synaptic signaling mediated by adenylyl cyclase (AC). Dex impaired the acquisition of neural cells, with a peak effect when given in the immediate postnatal period. In association with this defect, Dex also elicited biphasic effects on cholinergic presynaptic development, promoting synaptic maturation at a dose (0.05 mg/kg) well below those used therapeutically, whereas the effect was diminished or lost when doses were increased to 0.2 or 0.8 mg/kg. Dex given postnatally also disrupted the expression of adrenergic receptors known to participate in neurotrophic modeling of the developing brain and evoked massive induction of AC activity. As a consequence, disparate receptor inputs all produced cyclic AMP overproduction, a likely contributor to disrupted patterns of cell replication, differentiation, and apoptosis. Superimposed on the heterologous AC induction, Dex impaired specific receptor-mediated cholinergic and adrenergic signals. These results indicate that, during a critical developmental period, Dex administration leads to widespread interference with forebrain development, likely contributing to eventual, adverse neurobehavioral outcomes.

Developmental exposure to terbutaline and chlorpyrifos: pharmacotherapy of preterm labor and an environmental neurotoxicant converge on serotonergic systems in neonatal rat brain regions

Developmental exposure to unrelated neurotoxicants can nevertheless produce similar neurobehavioral outcomes. We examined the effects of developmental exposure to terbutaline, a tocolytic beta2-adrenoceptor agonist used to arrest preterm labor, and chlorpyrifos (CPF), a widely used organophosphate pesticide, on serotonin (5HT) systems. Treatments were chosen to parallel periods typical of human developmental exposures, terbutaline (10 mg/kg) on postnatal days (PN) 2-5 and CPF (5 mg/kg) on PN11-14, with assessments conducted on PN45, comparing each agent alone as well as sequential administration of both. Although neither treatment affected growth or viability, each elicited similar alterations in factors that are critical to the function of the 5HT synapse: 5HT1A receptors, 5HT2 receptors, and the presynaptic 5HT transporter (5HTT). Either agent elicited global increases in 5HT receptors and the 5HTT in brain regions possessing 5HT cell bodies (midbrain, brainstem) as well as in the hippocampus, which contains 5HT projections. For both terbutaline and CPF, males were affected more than females, although there were some regional disparities in the sex selectivity between the two agents. Both altered 5HT receptor-mediated cell signaling, suppressing stimulatory effects on adenylyl cyclase and enhancing inhibitory effects. When animals were exposed sequentially to both agents, the outcomes were no more than additive and, for many effects, less than additive, suggesting convergence of the two agents on a common set of developmental mechanisms. Our results indicate that 5HT systems represent a target for otherwise unrelated neuroteratogens.

Developmental and metabolic implications of the hypoxic ventilatory response

This review explores the evidence to support the leading hypothesis that the metabolic response to hypoxia early in life provides the pathophysiological basis for the metabolic syndrome. Hypoxia is a frequent occurrence during early development and induces a state of energy depletion that triggers a wide range of 'metabolic' responses to preserve homeostasis. Recent interest in the sequelae of energy depletion through hypoxic mechanisms has grown, particularly because of demonstrated links with ensuing metabolic abnormalities and increased risk for future cardiovascular disease. The 'metabolic syndrome' refers to the combination of obesity, hyperinsulinaemia, dyslipidaemia and hypertension in adults. The metabolic responses to energy depletion during early development provide explanations for some of the mechanisms that ultimately lead to serological features of metabolic dysfunction in children with sleep-disordered breathing. Thus, the acute compensatory response of energy conservation to hypoxia during early development at the cellular, serological and whole organism levels suggests that the metabolic abnormalities that develop later in life may in fact originate very early in life; in other words, constitute early life antecedents of adult disease. Evidence regarding the circumstances under which responses to hypoxia become maladaptive will be discussed, with a focus on chronic conditions and those associated with intermittent respiratory dysfunction such as sleep-disordered breathing.

Women's mental health during pregnancy influences fetal and infant developmental and health outcomes

Women's mental health during pregnancy has important implications not only for the well-being of the mother, but also for the development, health, and well-being of her unborn child. A growing body of empirical evidence from population-based studies suggests that two indicators of women's mental health during pregnancy--psychosocial stress and social support--may exert a significant influence on fetal development and infant birth outcomes, such as birth weight and length of gestation, even after controlling for the effects of established sociodemographic, obstetric, and behavioral risk factors. This paper describes the role of three major biological systems involved in the physiology of pregnancy and stress physiology: neuroendocrine, immune/inflammatory, and cardiovascular systems. These systems have been hypothesized to mediate the effects of maternal mental health on fetal developmental and health outcomes, and a central role has been proposed for placental corticotropin-releasing hormone in this process. However, not all women reporting high prenatal stress and/or low social support proceed to develop adverse birth outcomes, raising the question of the determinants of susceptibility/vulnerability in the context of high stress and/or low social support. In this context, the role of race/ethnicity and genetic predisposition are discussed as two promising avenues of further investigation.